Apple Inc. v. Samsung Electronics Co. Ltd. et al

Filing 561

Declaration in Support of #559 Declaration in Support, filed byApple Inc.. (Attachments: #1 Exhibit 3.02, #2 Exhibit 3.03, #3 Exhibit 3.04, #4 Exhibit 3.05, #5 Exhibit 3.06, #6 Exhibit 3.07, #7 Exhibit 3.08, #8 Exhibit 3.09, #9 Exhibit 3.10, #10 Exhibit 3.11, #11 Exhibit 3.12, #12 Exhibit 3.13, #13 Exhibit 3.14, #14 Exhibit 3.15, #15 Exhibit 3.16, #16 Exhibit 3,17, #17 Exhibit 3.18, #18 Exhibit 3.19, #19 Exhibit 3.20, #20 Exhibit 3.21, #21 Exhibit 3.22, #22 Exhibit 3.23, #23 Exhibit 3.24)(Related document(s) #559 ) (Jacobs, Michael) (Filed on 12/29/2011)

EXHIBIT 3.10

WO 97/23738

PCT/US96/20664

26

6) In a capacitive sensor that measures the capacitance to a ground of a plate, the plate electrically connected to the

ground by a shunting conductor that is not part of the sensor, the shunting conductor substantially conducting
electncal current puises having durations greater than a first predetermined value, the shunting conductor not
5

conducting current pulses having durations substantially less than a second predeterrmned value, an improved
capacanve measurement means compnsmg:
a source of de voltage;
pulse generating means generating a charging pulse and a subsequent dischargmg pulse, at least
one of the charging and the dischargmg pulses having a duration less than the second

10

predetermined value;

a charging switch having an open state and a closed state, the charging switch moving from its
open to its closed state responsive to the charging pulse, the charging switch connecting the

voltage source to the plate when in its closed state, the chargmg switch otherwise disconnecting
the voltage source from the plate;
15

a dischargmg switch having an open state and a closed state, the discharging switch moving from

its open state to its closed state responsive to the discharging pulse, the dischargmg switch
connecting the plate to a charge measuring means when in its closed state, the dischargmg
switch otherwise not connecting the plate to the charge measuring means;

20

whereby a quantity of charge representative of the capacatance of the plate is transferred to the charge
measurement means.

7) The capacitive sensor of Claim 6 further comprising a controller having an output responsive to a change in the
measured capacitance, the change associated with motion of an object proximate the plate.

25
8) Re capacitive sensor of Claim 6 wherein the charge measurement means comprises a charge detecting
capacitor.

9) Re capacitive sensor of Claim 8 further comprising an analog to digital converter electrically connected
30

intermediate the charge detecting capacitor and a microprocessor, the analog to digital converter controlled by the
microprocessor to provide a digital representation of a voltage across the detection capacitor.

10) He capacitive sensor of Oaim 8 further comprising a charge subtractor controlled by the microprocessor to
subtract a predetermined quantity of charge from the charge detectmg capacitor.

35
11) Re capacitive sensor of Gaim 8 wherein the charge measurement means further comprises a reset transistor
and wherein both the charging and the discharging switches comprise transistors.
12) The capacitive sensor of Qaim 6 further comprising means controlling the pulse generating means to supply a

40

predetermined number of the charging pulses and the same predetermined number of the discharging pulses, each
of the discharging pulses being generated subsequent to one of the charging pulses and before the next sequential

AMBIDED SHEET (MRCLE W)

APLNDC00026040

WO 97/23738

PCT/US96/20664

27
one of the charging pulses, whereby the charging and discharging switches close in sequence the predetermined
number of times.
13) The capacitive sensor of Qaim 6 further comprising means controlling the pulse generatmg means to van an
5

mterval having a pseudo-random duration subsequent to the charging and dischargmg switches closing in sequence
the predetermined number of times and to thereafter again supply the predetermined number of the charging and

the discharging pulses.
14) The capacitive sensor of Gaim 6 further comprising means controlling the pulse generating means to supply a

10

predetermined number of the chargmg pulses and the predeternined number of the discharging pulses, each of the
discharging pulses being generated subsequent to one of the chargmg pulses and before the next seguemial one of
the charging pulses, whereby the charging and discharging switches close in sequence the predetermined number

of times.

15

15) The capacitive sensor of Claim 6 wherein the shunting conductor comprises water spilled about a spout and
wherein the charge measurement means suppbes an input to a controDer havmg a stored value representative of a

predetermined value of the input , the controller providing a control output controlling an electrically-actuated
valve to open when the input exceeds the predetermined value, the valve, when open, supplying water to the
spout.

20
16) The capacitive sensor of Claim 15 wherein the spout comprises a bubbler portion of a water fountain, wherein

the plate comprises a metallic basin of the water fountain, the basin having no metallic electrical connection to a
grounded metallic portion of the water fountain.
25

17) The capacitive sensor of Qaim 15 wherein a metal body adjacent a wash-basin comprises the spour and the
plate, the apparatus further comprising a dielectric tubular member conveying water from the valve to the spout..

18) He capacitive sensor of Gaim 6 wherein the charging pulse has a duration less than the second predetermined
value.

30
19) Re capacitive sensor of Qaim 18 wherein the discharging pulse has a duration less than the second
predetermined value.

20) The capacitive sensor of Claim 6 wherein the dischargyng pulse has a duration tess than the second
35

predetermined value.

AMENDED SHEET (ARTICLE 19)

APLNDC00026041

WO 97/23738

PCT/US96/20664

28
21) In a capacitive sensor sensing an object adjacent thereto by measuring the capacitance to an electnc ground of
a plate connected to the ground by a shunting conductor that is not a portion of the sensor, the shunting

conductor substantially conducting electrical current pulses having durations greater than a first predetermined
value, the shunting conductor substantially not conducting current pulses having durations less than a second

5

predetermined value, a method of measunng the capacitance, the method comprising the steps of:
a)

closing a charging switch to connect the plate to a source of charging voltage for a charging
interval having a predetermined chargmg duration and thereafter opemng the charging

switch to disconnect the plate from the voltage source;

10
b)

closing a discharging switch to connect the plate to a charge measurement means having an
output representative of the electrical charge transferred thereinto, the plate connected to
the charge measurement means for a discharging interval having a predetermined discharge
duration, and thereafter opening the dischargmg switch; and

15
c)

reading the output of the charge measur•,tentmeans,

wherein at least one of the charging and discharging durations is less than the second predetermined value.
20

22) The method of Claim 21 wherein both the charging duration and the discharging duration are less than the
second predetermined valne..

23) The method of Gaim 21 wherein the step of closing the dischargmg switch is carried out only after the
charging switch has been opened to disconnect the plate from the voltage source.

25
24) The method of Gaim 21 comprising an additional step bl intermediate step b) and step c) of repeating steps a)
and b) a predetermined number of times before carrying out step c).

25) The method of Qaim 21 comprising additional steps b1 and b2 intermediate steps b) and c) of:
30

bt) waiting for a delay time interval having a duration less than the first predetermined value, and
b2) repeating steps a), b) and b1) a predetermined number of times before doing step c).

26) The method of Qaim 21 compnsing additional steps bl and b2intermediate steps b) and c) of:
bt) waiting for a delay time interval having a duration greater than the 6rst predetermined value, and

35

b2) repeating steps a), b) and bt) a predetermined number of times before doing step c).
27) The method of Qaim 21 wherein the charge measurement means comprises a charge detecting capacitor, and
wherein step c) comprises the substeps of: ct) connecting the charge detecting capacitor to an analog-to-digital
converter, c2) digitizing the magnitude of a voltage on the detection capacitor, and c3) communicating the

40

digitized voltage to a microprocessor.

AMENDED SHEET (ARTICLE 19)

APLNDC00026042

WO 97/23738

PCT/US96/20664

29
28) In a capacitive sensor measuring a change in capacitance between a capacitive coupling plate and an electrical
ground, the change in capacitance operatively associated with the presence of a user proximate the plate, the sensor

having an output to a control means for controlling the actuation of an electrically-operated valve supplying water
5

to a spout, an improvement comprising
a means of generating electrical pulses;
a source of DC voltage;
a charging switch intermediate the voltage source and the plate, the charging switch having a
closed state electrically connecting the source to the plate and an open state electncally

10

disconnecting the source from the plate, the chargmg switch switching between the closed and
the open states responsive to a first pulse from the pulse generating means;
a discharging switch intermediate the plate and a charge measuring means having an output, the
dischargmg switch having a closed state electrically connecting the plate to the charge measuring
means and an open state electrically discannecting the plate from the charge measuring means,

15

the discharging switch switching between the closed and the open states responsive to a second
pulse from the pulse generating means; and

wherein the control means stores a predetermined electric charge value, the control means receiving the output of

the charge measunng means and controlling the valve to be open if the output from the charge measuring means is
20

greater than the predetermined charge value, the control means otherwise controlling the valve to be closed.

29) Apparatus of Gaim 28 wherein the spout comprises a water fountain bubbler, wherein the coupling plate
compnses a porton of a basin of the water fountain, the basin of the water fountain having no metallic conducting
path to a grounded metallic portion of the water fountain.
2$

30) Apparatus of Gaim 28 further comprising a dielectric tubular member connected intermediate the valve and a

metal body, the metal body comprising both the spour and the coupling plate, the metal body electrically
connected to the controller.
30

31) The improved sensor of Gaim 28 wherein the 6rst pulse has a first duration when the valve is closed and a
second duration, longer than the 6tst duration, when the valve is open, and wherein the second pulse has a third
duration when the valve is closed and a fourth duration, longer than the third duration, when the valve is open.

32) Apparatus of Gaim 28 wherein the control means comprises means replacing the stored predetermined charge
35

vaine with a second stored predetermined charge value responswe to an mput representative of a change in an

ambient condition.

AMENDED SHEET (ARTICLE 19)

APLNDC00026043

WO 97/23738

PCT/US96/20664

30
41) A method of operating a capacitive sensor wherein the presence of an object proximate the sensor is detected
by measunng a change m a capactance to an electrical ground of a sensing plate, the method comprising the steps
oE

5
a) setting an output of a charge detector to a first predetermined voltage;
b) chargmg the plate from a DC voltage source to a second predetermined voltage;

10

c) connecting, for a predetermined dischargog interval, the plate to the charge detector, and

d) digitizing the output of the charge detector;
e) storing the digitized output of the charge detector as a value in a memory operatively associated with a
15

microprocessor,

f) setting the output voltage of the charge detector to the first predetermined vohage;
g) repeating steps b) through d); and

20
h) combining, by means of an algorithm performed by the microprocessor, the current digitized output of
the charge detector and the value earlier stored in the memory.

42) The method of Gaim 41 further comprising a step subsequent to step c) and prior to step g) of waiting for an
25

interval of pseudo-random duration.

43) The method of Gaim 41 further comprising a step intermediate steps b) and d) of reducing, by means of a
charge subtractor circuit, the output voltage of the charge detector by a predetermined incremental value.

30

44) The method of Gaim 41, wherein the plate is connected to a shunting conductor that is not a portion of the
sensor, the shunting conductor substantially conducting electrical current pulses having durations greater than a
first predetermined duration, the shunting conductor substantially not conducting current pulses having durations
less than a second predetermined duration, and wherein the predetermined discharging interval is shorter than the
second predetermined duration..

35
45) The method of Osim 41 further comprising a step intermediate steps c) and d) of repeating steps b) through c)
a predetermined number of times.

46) The method of Gaim 41 further comprising a step bl) intermediate steps b) and c) of bt) disconnecting the
40

plate from the DC vohage source.

AMENDED SHEET (ARflCLE 19)

APLNDC00026044

WO 97/23738

PCT/US96/20664

31
47) A method of operating a capacitive sensor wherein the presence of an ob¡cct proximate the sensor is detected
by measuring a change in a capacitance to an electrical ground of a sensing plate, the method comprising the steps
of:

5
a) setting an output of a charge detector to a first predetermined voltage;

b) connecting the plate to a source of DC voltage for a chargmg interval having a first predetemuned
duration;

10
c) connecting, for a discharging interval having a second predetemuned duration, the plate to the charge
detector,

d) disconnecting the plate from the charge detector, and

15
e) digitizing the output of the charge detector, the digitized output representing the capacitance;
f) storing the digitized output of the charge detector as a value in a memory operatively associated with a

smcroprocessor,

20
g) repeating steps b) through e); and
h) combining, by means of an algorithm performed by the microprocessor, the current digitized output of
the charge detector and the value eadier stored in the memory.

25
48) The method of Qaim 47 further comprising a step following step d) of repeanng steps b) through d) a
predetermined number of repetitions.
49) The method of Claim 47 further comprising a step intermediate steps b) and e) of reducing, by means of a

30

charge subtractor circuit, the output voltage of the charge detector for a predetermined incremental value
50) The method of Gaim 47, wherein the plate is connected to a shunang conductor that is not a portion of the
sensor, the shunting conductor substantially conducting electncal current pulses having durations greater than a
first predetermined duration, the shunting conductor substantially not conducting current pulses having durations

35

less than a second predetermined duration, and wherein the predetermined dischargmg interval is shorter than the

second predetermined duration.
51) The method of Gaim 47 furtber comprising a step bl) intermediate steps b) and c) of bl) disconnecting the

plate from the DC voltage source.
40

AMENDED SHEET (ARTICLE 19)

APLNDC00026045

WO 97/23738

PCT/US96/20664

32
52) A method of operating a capacitive sensor wherein the presence of an object proximate the sensor is detected

by measuring a change in a capacitance to an electrical ground of a sensing plate, the method using a DC voltage
source and a charge detector, the method comprising the steps of:

5

a) setting an output of the charge detector to a first predetermined value;
b) charging the plate from the DC voltage source to a second predetermined value;

c) connecting, for a predetermined discharging interval, the plate to the charge detector;

10
d) repeating steps b) and c) a 6rst predetennined number of times, the first predetermined number equal
to or greater than zero;

e) measuring the output of the charge detector;

15
f) storing the measured output as a representation of the capacitance;

g) repeatmg steps a) through f) a second predetermined number of times, thereby obtaining one more
than the •eccad predetermined number of representations of the capacitance; and

20
h) combimng the one more than the second predetermined number of representations of the capacitance
to create an aggregate representation of the capacitance.

AMENDED SHEET (ARTICLE 19)

APLNDC00026046

WO 97/23738

PCT/US96/20664

33

Statement under Article 19(1)

Amendments are made to clearly distinguish the invention from the prior art. The present
invention provides a "single-plate" capacitive sensor in which changes in the capacitance between a single
sensing plate and a ground are indicative of an object proximate the sensor. The Kerber reference, cited in
the International Search Report, describes a "double-plate" charge transfer capacitive measurement
2trangement requiring portions of the sensing circuit to be directly connected to both plates of a capacitor

under test. Kerber provides no teaching on proximitv sensing, nor is his arrangement adaptable thereto.
The cited Gorski reference describes a dual-plate capacitive proximity sensor that does not use charge
transfer methods.

APLNDC00026047

WO 97/23738

PCT/US96/20664

1/9

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WO97/23738

PCT/US96/20664

2/9
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APLNDC00026049

WO97/23738

PCT/US96/20664

3/9

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APLNDC00026050

WO 97/23738

PCT/US96/10664

4/9

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APLNDC00026053

WO97/23738

PCT/US96/20664

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APLNDC00026054

WO97/23738

PCT/US96/20664

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APLNDC00026055

WO 97/13738

PCT/US96/20664

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APLNDC00026056

INTERNATIONAL SEARCH REPORT

Ina .ional appücation No.
PCTIUS96/20664

A.

CLASSIFICATION OF SUBJECT MATTER

IPC(6) :F16K 31/06; EO3C 1/05; GOIR 27/26
US CL : 251/129.04; 4/623; 239/24; 324/678
According to international Patent Classification (IPC) or to both national classification and IPC

B.

FIELDS SEARCHED

Minimum documentation searched (classification system followed by classification symbols)

U.S. :

251/129.04; 4/623; 239/16,24; 222/52; 324/677,678

Documentationscarchedotherthan minimum documentation to the extent that such documents are included in the ficids scarched

Electronic data base consuhed during the intemational search (name of data base and, where practicable, search terms used)

C.

DOCUMENTS CONSIDERED TO BE RELEVANT

Category•

Citation of document, with indication, where appropriate, of the relevant passages

Relevant to claim No.

X
Y

US 4,806,846 A (KERBER) 21 February 1989, fig. 1 and col. 1,3,6,8,12,14,
2, line 58 through col. 6, line 5.
21-23

Y

US 3,333,160 A (GORSKI) 25 July 1967, fig. 2 and col. 2, 7,28,33,34,39,
line 23 through col. 4, line 64.
4 1 , 42 , 4448,50-55

Y

US 5,159,276 A (REDDY, 111) 27 October 1992, figs. 3 and 4,5,13
5 and col. 3, line 58 through col. 6, line 40.

4, 5,7,13,1820 , 24-2 6, 2
8,33,34,39,41,
42,44-48,50-55

O Further documents are listed in the continuation of Box C.
•

s,-a....ugonce of casi documcata

'A'

docannmadefining the generainme of the art which is not
to be of particular selevance

.E'

cartier et---•publishedon or aner the international filing date

•L'

a---•which may throw doubts on priority claim(s) or which is
cited to establish the publimtion dale of another cilstian or other
(v specify

O'

A---•referring to an oral

See pa m famBy onex.
'T

taler documunghshmi anar de internstml fding dem orgmity
date and not in connicswith the application but cited to u::dcas:==dthe
principle er theory underlying ibe invention

'X'

of-œ: c
Ibe
when the docmacnt is thkin SÎDOS

'Y

of particular relevance: the claimed învcelion teamat be
to involve an inventive step when the A---* is

-i-•e, nac. exhibaion or other

combined with one or more other auch docmncats, such combination

means
P"

being obvioamin a person skilled in the art

a---•publishedprior to the intemationalfding date but inter than

the priority deze claimed

Date of the actual compiction of the international search

•&'

docuissent Izzesaber of the same patent fainDy

Date of mailing of the intemational scarch report

21 APRIL 1997
Name and mailing address of the ISAIUS

Authorized officer

Commissioner of Patents and Trademarks

Box FCI
Washington, D.C. 2023)

Fa synje Ng

µ03) ggggg

JOHN RIVELL
Telephone No.

(703} 308-2599

Form PCTilSAl210 (second sheetXJuly 1992)*

APLNDC00026057

(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)

(19) World Intellectual Property Organization
(43) International Publication Date

(10) International Publication Number

23 October 2003 (23.10.2003)

PCT

(51) International Patent Classification':
GO9G 3/02

G08C 21/00,

(21) International Application Number:

PCT/USO3/l1015

(22) International Filing Date:

(81) Designated States (national): AE, AG, AL, AM, KI, AU,
AZ, BA, BB, BG, BR, BY, BZ, CA, CH, CN, CO, CR, CU,

CZ, DE, DK, DM, DZ, EC, EE, ES, FI, GB, GD, GE, GH,
GM, HR, HU, ID, IL, lN, IS, JP, KE, KG, KP, KR, KZ, LC,
LK, LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW,
MX, MZ, NI, NO, NZ, OM, PH, PL, PT, RO, RU, SC, SD,

10 April 2003 (10.04.2003)

(25) Filing Language:

English

(26) Publication Language:

WO 03/088176 A1

English

(30) Priority Data:
60/372,009
10/338,765

11 April 2002 (11.04.2002)
7 January 2003 (07.0L2003)

US
US

(71) Applicant: SYNAPTICS, INC. [US/US]; 2381 Bering

SE, SG, SK, SL, TJ, TM, TN, TR, TT, TZ, UA, UG, UZ,
VC, VN, YU. ZA, ZM, ZW.
(84) Designated States (regional): ARIPO patent (GH, GM,
KE, LS, MW, MZ, SD, SL, SZ, TZ, UG, ZM, ZW),
Eurasian patent (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM),
European patent (AT, BE, BG, CH, CY, CZ, DE, DK, EE,
ES, FI, FR, GB, GR, HU, IE, IT, LU, MC, NL, PT RO,
SE, SI, SK, TR), OAPI patent (BF, BJ, CF, CG, CI, CM,

Drive, San Jose, CA 95131 (US)
(72) Inventors: TRENT, Raymond, A., Jr.; 1177 Hanchett
Avenue, San Jose, CA 95126 (US). SHAW, Scott, J.; 4221
San Juan Avenue, Fremont, CA 94536 (US). GILLESPIE,
David, W.; 16100 Soda Springs Road, Los Gatos, CA
95033 (US). HEINY, Christopher; 2381 Bering Drive,
San Jose, CA 95131 (US). HUIE, Mark, A.; 801 Walnut
Street #9, San Carlos, CA 94070 (US).

(74) Agent: COPPES-GATHY, Nicole, E.; Sierra Patent
Group, Ltd., P.O. Box 6149, Stateline, NV 89449 (US).

GA, GN, GQ, GW, ML, MR, NE, SN, TD, TG).
Published:
-

with international search report

-

before the expiration of the time limit for amending the
claims and to be republished in the event of receipt of
amendments

For two-letter codes and other abbreviations, refer to the "Guidance Notes on Codes andAbbreviations"appearing at the beginning ofeach regular issue ofthe PCT Gazette.

(54) Title: CLOSED-LOOP SENSOR ON A SOLID-STATE OBJECT POSITION D

94

GO

00
CD

I
I

-

92

94

N (57) Abstract: The technical features mentioned in the abstract do not include a reference sign between parentheses (PCT Rule
8.l(d)). The present invention discloses an object position detector. The object position detector comprises a touch sensor (10)
formed as a closed loop (12) and having a physical constraint formed on an upper surface of the touch sensor (10) and coextensive
with the closed loop (12). The touch sensor (10) is configuæd to sense motion of an object proximate to the closed loop (12). The
object position detector also comprises a processor (16) coupled to the touch sensor (10) and is programmed to generate an action in
response to the motion on the touch sensor (10).

BEST AVAl .ABLE COPY
APLNDC00026058

WO 03/088176

PCT/USO3/11015

5

CLOSED-LOOP SENSOR ON A SOLID-STATE OBJECT
POSITION D- - -- - OR
10

BACKGROUND
User interfaces on digital information processing devices often have more
information and options than can be easily handled with buttons or other physical controls.

15

In particular, scrolling of documents and data, selection of menu items, and continuous value
controls, such as volume controls, can be difficult to control with buttons and general
purpose pointing devices. These buttons and pointing devices are inherently limited in how
far they can move or how many options can be selected. For example, a computer mouse,
though it can - - a pointer or cursor indefinitely, has limits to how far it can move without

20

being picked up and repositioned, which limits its usability in these situations.
Solutions to this problem have included:
a.

Keys, such as "page up" and "page down" and arrow keys, that are

specifically designated to maneuver through or control data;
b.
25

Provisions for scrollbars in a user interface which can be used to

scroll data long distances by using a standard computer pointing device controlling a cursor;

c.

Similarly controlled (as in b.) hierarchical menus or choices;

d.

Graphical user interface elements such as "slider bars" and "spin

controls",to vary a parameter over an arbitrary range;
e.
30

Scrolling "wheels" on standard pointing devices;

f.

Physical knob controls, which, when used to control a user interface

are often referred to in the art as "jog dials". Some knobs and dials output quadrature

signals to indicate direction of motion;
g.

Trackballs that rely on optically or mechanically sensed spherical

controls to provide two-dimensional sensing; and

35

h.

A capacitive two-dimensional object position sensor that can be used

for scrolling by providing a "scrolling region", where users can slide their fingers to

generating scrolling actions.
1

APLNDC00026059

WO 03/088176

PCT/USO3/11015

SYN-113PCT
5

The disadvantages of these prior solutions are as follows:
a.

Designated Keys: These typically require designated space on the

keyboard as well as supporting electronics and physical stmetures. Keys usually limit the
control they offer to the user over the information being scrolled or the function being
performed to distinct values. For example, page up and page down keys enable the user to
10

increment through a document at a constant rate of page by page only.

b.

Scroll bars controlled by a pointing device and a cursor: These

elements require the user to move long distances across a display and/or select relatively
small controls in order to scroll the data. Additionally, these scroll bars take up room on the

display that can be used for other purposes.
15

c.

Hierarchical menus controlled by a pointing device or by key

combinations: These have a similar problem to scroll bars, in terms of the complexity of the
targeting task that faces the user. First, the user must hit a small target near the edge of a
screen, and then the user must navigate along narrow paths to open up additional layers of
menu hierarchy. Shortcut keys, which usually consist of key combinations, are typically
20

non-intuitive and hard to remember.
d.

"Sliders" and "spin controls" controlled by a pointing device or by

key combinations: These have targeting problems similar to scroll bars and hierarchical
menus (sometimes exacerbated by the targets usually being even smaller than in the cases of
scrollbars and menus).

25

e.
Physical Scroll Wheels on mice: The user is unable to scroll very far
with these wheels due to mechanical limitations in how far the user can move the wheel in a
single stroke. These mechanical limitations are because of the construction of the wheel
itself or because of interactions between the wheel and nearby physical features (such as the
wheel mounting or the device housing). The limits on the practicallcomfortable length of

30

the basic finger motion also severely restrict the ability of the user to scroll significant

distances in one stroke. Additionally, these wheels are mechanically complex and take up a
lot of space.
f.

Physical knobs or "Jog Dial" controls: %ese have the disadvantages

of being relatively large and mechanically complex. Similar to the scroll wheel, the knob or
35

dial requires some amount of friction to limit accidental activation, which increases the

difficulty of fine adjustments. Additionally, it is difficult to use a physical knob or dial with
a great degree of accuracy, and the knob or dial inherently has inertia that may cause
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overshoot in large motions. The physical knobs or dials are often mechanically limited in
range of rotation imposed by the construction or by the interactions of the knob or dial with
nearby physical features.
g.

Trackballs: These are similar to the physical knobs in that they have

the disadvantages of being bulky and mechanically complex. The trackball is difficult to use
10

with a great degree of accuracy, and the trackball inherently has inertia that may cause

overshoot in large motions. Additionally, the trackball presents additional complexity in
that it presents control of two dimensions of motion in a way that makes it difficult for users
to limit their inputs to a single dimension. Finally, the input is limited either by the
construction of the trackball and its housing, or by natural limits on comfortable/practical .

15

finger motion, or both.
h.

Scroll Regions: These are limited by the physical limitation that a

user's finger will eventually reach the end of the scrolling region and the user will have to
lift their finger, replace it on the sensor inside the region, and continue the motion. The user
must perform many repetitive motions of the same finger to scroll long distances with a
20

scroll region.
The disadvantages of the prior art can be remedied by devising a user interface that
enables scrolling, selecting, and varying controls over a long range of possible positions and
values.

25

SUMMARY
The drawbacks and disadvantages of the prior art are overcome by a closed-loop
sensor on a solid-state object position detector.
The present disclosure discloses a solid-state object position detector. The solid-state
object position detector comprises a touch sensor formed as a closed loop having a physical

30

constraint formed on an upper surface of the touch sensor and coextensive with the closed

loop. The touch sensor is configured to sense motion of an object proximate to the closed
loop. The object position detector also comprises a processor coupled to the touch sensor
and is programmed to generate an action in response to the motion on the touch sensor.
The present disclosure also discloses a solid-state object position detector,

35

comprising a two-dimensional touch sensor having a tactile guide formed on an upper
surface of, and coextensive with, the two-dimensional touch sensor. The two-dimensional
touch sensor is configured to sense motion of an object proximate to the two-dimensional
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touch sensor. The solid-state object position detector also comprises a processor coupled to
the two-dimensional touch sensor and configured to report only one variable indicating the
position, such as the angular position, of an object proximate to the two-dimensional touch
sensor. The processor is programmed to generate an action in response to the motion on the
two-dimensional touch - --

10

The present disclosure also discloses a combination comprising a solid-state object
position detector, a pointing input device, and a processor. The solid-state object position
detector has a touch sensor formed as a closed loop. The solid-state object position detector
has a tactile guide formed on an opper surface of the touch sensor and coextensive with the
closed loop. The touch sensor is configured to sense a first position of an object proximate

15

to the closed loop. The pointing input device is disposed proximate-to the solid-state object
position detector and is configured to sense a first pointing input of a user. The processor is
coupled to the solid-state object position detector and to the pointing input device. The
processor is programmed to generate at least one action in response to the first position and

at least one action in response to the first pointing input. The pointing input device can be a
20

mouse, a touch pad, a pointing stick, a slider, a joystick, a touch screen, a trackball or
another solid-state object position detector.
The present disclosure also discloses another embodiment of a combination
comprising a solid-state object position detector, a control input device, and a processor.
The solid-state object position detector has a touch sensor formed as a closed loop. The

25

solid-state object position detector has a tactile guide formed on an upper surface of the

touch sensor and coextensive with the closed loop. The touch sensor is configured to sense a
first position of an object proximate to the closed loop. The control-input device is disposed
proximate to the solid-state object position detector and is configured to sense a first control
input of a user. The pv -ema is coupled to the solid-state object position detector and to the
30

control input device. The processor is programmed to generate at least one action in
response to the first position and at least one action in response to the first control input.
The control input device can be a button, a key, a touch sensitive zone, a scrolling region, a

scroll wheel, a jog dial, a slider, a touch screen, or another solid-state object position
detector.
35

The present disclosure also discloses a solid-state object position detector,
comprising a touch sensor having a first electrode and a plurality of second electrodes

disposed in a one-dimensional closed loop and proximate to the first electrode. The solid4

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state object position detector also comprises a processor coupled to the touch sensor. The
processor generates an action in response to user input on the touch sensor. The complexity
of the sensing circuitry used in the plurality of second electrodes can be reduced, such that
when only relative positioning is necessary, at least two of the plurality of second electrodes
are electrically connected or wired together.

10

The present disclosure also discloses a combination comprising a solid-state object
position detector, a touch pad, and a processor. The solid-state object position detector
comprises a touch sensor having a first electrode and a plurality of second electrodes
disposed in a one-dimensional closed loop and proximate to the first electrode. The touch

pad has a plurality of X electrodes and a plurality of Y electrodes. The first electrode is
15

electrically coupled to at least one of the plurality of X electrodes and the plurality of Y
electrodes. The processor is coupled to the touch sensor and to the input device. The

pr

r generates an action in response to user input on at least one of the touch sensor

and the touch pad. The complexity of the sensing circuitry used in the plurality of second
electrodes can be reduced, such that when only relative positioning is necessary, at least two
20

of the plurality of

d electrodes are electrically connected or wired together.

The present disclosure also discloses a solid-state object position detector,
comprising a touch sensor having a plurality of interleaving electrodes disposed proximate
to a one-dimensional closed loop; wherein each electrode is interdigitated with an adjacent

neighboring electrode. The solid-state object position detector also comprises a processor
25

coupled to the touch sensor. The processor generates an action in response to user input on

the touch sensor.
.

The present disclosure also discloses a solid-state object position detector,

comprising a touch sensor having a plurality of self-interpolating electrodes disposed
proximate to a closed loop. The solid-state object position detector also comprises a
30

processor coupled to the touch sensor. The processor generates an action in response to user

input on the touch sensor.
The present disclosure also discloses a method of calculating a position of an object
on an object position detector comprising receiving positional data from the object on a
touch sensor having a closed loop and interpolating the positional data to dete----L-- a

35

position of the object on the one-dimensional closed loop. The interpolating aspect of the
method further includes performing a quadratic fitting algorithm, a centroid interpolation

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algorithm, a trigonometric weighting algorithm, or a quasi-trigonometric weighting
algorithm.
The present disclosure also discloses a method of determining motion of an object on
a touch sensor of an object position detector. The method comprises receiving data of a first
position of the object on a closed loop on a touch sensor of the object position detector,

10

receiving data of a second position of the object on the closed loop, and calculating motion
from the second position and the first position.

The method can further comprise

determining if the motion is equal to or greater than a maximum angle and adjusting the
motion based on whether the motion is equal or greater than the maximum angle. The
method of adjusting the motion can be subtracting 360° from the motion. The method can
15

further comprise determining if the motion is less than a minimum angle and adjusting the
motion based on whether the motion is less than the ---:--:---um angle. The method of
adjusting the motion can be adding 360°to the motion.
BRIEF DES= = = •ON OF FIGURES

20

Referring now to the figures, wherein like elements are numbered alike:
FIG. 1 illustrates a block diagram of a solid-state closed-loop sensor;
FIG. 2 illustrates a location of a closed-loop sensor on a laptop near a keyboard;

FIG. 3 illustrates a closed-loop sensor disposed on a conventional pointing device;

FIG. 4 illustrates wedge-shaped electrodes of a closed-loop sensor;
25

FIG. 5 illustrates lightning-bolt-shaped electrodes of a closed-loop sensor;

FIG. 6 illustrates triangle-shaped electrodes of a closed-loop sensor;
FIG. 7 illustrates rectangular-shaped electrodes that may be used in a linear section
of a closed-loop sensor;
FIG. 8 illustrates rectangular-shaped electrodes that may be used in a rectangular30

shaped closed-loop sensor;
FIG. 9 illustrates another example of triangle-shaped electrodes of a closed-loop
sensor;

FIG. 10 illustrates spiral-shaped electrodes of a closed-loop sensor;
FIGS. 11 to 17 illustrate various shapes of the path utilized on a closed-loop sensor;

35

FIG. 18 illustrates a cross-sectional view of V-shaped depressed grooves that define
the path on a closed-loop ,, 22,,;

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FIG. 19 illustrates a cross-sectional view of a raised projection that defines the path
on a closed-loop sensor;
FIG. 20 illustrates a cross-sectional view of U-shaped depressed grooves that define
the path on a closed-loop sensor;

10

FIG. 21 illustrates a cross-sectional view of a bezel that defines the path on a closedloop sensor;
FIGS. 22 and 23 illustrate the motions of an input object on a closed-loop sensor and
the effects on a host device;

FIG. 24 illustrates a motion on a closed-loop sensor for navigating menus;
FIG. 25 illustrates a motion on a closed-loop sensor for vertically navigating menus
15

using an additional key;
FIG. 26 illustrates a motion on a closed-loop sensor for horizontally navigating
witlun open menus;

FIG. 27 illustrates a motion on a closed-loop sensor for a value setting control;
FIG. 28 illustrates a closed-loop sensor electrically
20

ted to a touch pad;

FIG. 29 illustrates the potential electrical connections of two closed-loop sensors to a
touch pad;
FIG. 30 illustrates several closed-loop sensors electrically connected to a touch pad;
FIG. 31 illustrates two closed-loop sensors with indicator electrodes electrically
connected to a touch pad;

25

FIG. 32 illustrates a graph of the signals from a closed-loop sensor with an indicator

electrode electrically connected to a touch pad;
FIG. 33 illustrates a top view of an exemplary closed-loop sensor;
FIG. 34 illustrates a side view of the cross-section of the exemplary closed-loop

sensor of FIG. 33;
30

FIG. 35 illustrates the lightning-bolt-shaped electrodes of an exemplary closed-loop
sensor having an interior opening and four exterior regions;
FIG. 36 illustrates a plurality of closed-loop sensors to vary the settings of audio
controls;

FIG. 37 illustrates two sets of two closed-loop sensors formed concentrically about a
35

single origin for an audio system;

FIG. 38 illustrates four closed-loop sensors for an audio system formed in concentric
circles about a single origin;
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FIG. 39 is a flow chart of a method of calculating a position of an object on a closedloop sensor by performing a quadratic fitting algorithm;

FIG. 40 is a graph of the second quadratic fitting step in which the three capacitance
measurements from the three adjacent electrodes are fitted to an inverted parabola;
10

FIG. 41 is a flow chart of a method of calculating a position of an object on a closedloop sensor by performing a centroid interpolation algorithm;
FIG. 42 is a flow chart of a method of calculating a position of an object on a closedloop sensor by performing a trigonometric weighting algorithm;
FIG. 43 is a flow chart of a method of calculating a position of an object on a closedloop

15

r by performing a quasi-trigonometric weighting algorithm;
FIG. 44 is a flow chart of a method of determining relative motion of an object on a

closed-loop won and
FIG. 45 is a flow chart of a method of using the angular component to determine the

sign of the traversal along the closed-loop path.
20

DET-

••DES•

« ·ON

Those of ordinary skill in the art will realize that the following description of the
present invention is illustrative only and not in any way limiting. Other embodiments of the
present invention will readily suggest themselves to such skilled persons.

An object position detector is disclosed comprising a touch (or proximity) sensor (or
25

touch pad or touch screen or tablet), such as a capacitive, resistive, or inductive sensor
designed to sense motions along a substantially closed loop, and referred to herein as a

closed-loop sensor. This closed-loop sensor can be used to enhance the user interface of an
information-processing device. A loop area on a closed-loop sensor can be defined by a
tactile guide. Preferably, the closed-loop sensor is defined by a physical constraint. The

30

position of an input object (or finger or pointer or pen or stylus or implement) is measured
along this loop. When the input object moves along this loop, a signal (or instruction) is
generated that causes an action at the host device. For example, when the input object
moves in the clockwise direction along this loop, a signal is generated that can cause the

data, menu option, three dimensional model, or value of a setting to traverse in a particular
35

direction; and when the input object moves in the counter-clockwise direction, a signal is
generated that can cause traversal in an opposite direction. This looping motion of the input
object within the loop area need only be partially along the loop, or if the looping motion
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completes one or more loops, be approximate and notional. A strict loop can imply that the
input object would eventually return to exactly the same position on the sensor at some
point. However, the sensor may report the input object's position with greater accuracy than
the input object can actually repeatably indicate a position. Hence, enabling the sensor to
accept a close approximation to a loop as a completed loop is desirable.

10

A closed-loop sensor can be physically designed or electrically laid out in such a way
as to naturally report in only one coordinate. This single coordinate design, which will be
referred to as "one-dimensional" within this document, is one-dimensional in that the closedloop sensor inherently outputs information only in one variable; the closed-loop sensor itself
may physically span two or more dimensions. For example, a closed-loop sensor can consist

15

of a loop of capacitive electrodes arranged along the perimeter of a closed loop of any shape
herein described. The absolute position of the input object on a one-dimensional closedloop sensor can be reported in a single coordinate, such as an angular (0) coordinate, and the

relative positions (or motions) of the input object can be reported in the same (such as
angular) units as well.
20

The operation of the present invention with a host device is illustrated in the block

diagram of FIG. 1. A signal is generated at the closed-loop sensor 10 and is then decoded by
the closed-loop path decoder 12. A message is generated by the message generator 14 and

the message is transmitted to the host device 16. The host device 16 then interprets the
message and causes the appropriate action on a display (not shown).
25

Host device 16 is a processing system. The following is a description of an
exemplary processing system. However, the exact configuration and devices connected to

the processing system may vary.
The processing system has a Central Processing Unit (CPU). The CPU is a
processor, microprocessor, or any combination of processors and/or microprocessors that
30

execute instructions stored in memory to perform an application or process. The CPU is
connected to a memory bus and an Input/Output (I/O) bus.
A non-volatile memory such as Read Only Memory (ROM) is connected to CPU via
the memory bus. The ROM -t-- instructions for initialization and other systems commands
of the processing system. One skilled in the art will recognize that any memory that cannot

35

be written to by the CPU may be used for the functions of the ROM.

A volatile memory such as a Random Access Memory (RAM) is also connected to
the CPU via the memory bus. The

^M stores instructions for processes being executed
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and data operated upon by the executed p--es. One skilled in the art will recognize that
other types of memories, such as flash, DR M and SRAM, may also be used as a volatile
memory and that memory caches and other memory devices may also be connected to the
memory bus.
Peripheral devices including, but not limited to, a storage device, a display, an I/O

10

device, and a network connection device are connected to the CPU via an I/O bus. The I/O
bus carries data between the devices and the CPU. The storage device stores data and
instructions for processes unto a media. Some examples of a storage device include
read/write compact discs (CDs), and magnetic disk drives. The display is a monitor or other
visual display and associated drivers that convert data to a display. An I/O device is a

15

keyboard, a pointing device or other device that may be used by a user to input data. A

network device is a modem, Ethernet "card", or other device that connects the processing
system to a network. One skilled in the art will recognize that exact configuration and
devices included in or connected to a processing system may vary depending upon the
operations that the processing system performs.
20

The closed-loop sensor (or several closed-loop sensors) can be disposed in any

location that is convenient for its use with a host device, and optional other input devices. A
host system can be a computer, a laptop or handheld computer, a keyboard, a pointing
device, an input device, a game device, an audio or video system, a thermostat, a knob or

dial, a telephone, a cellular telephone, or any other similar device. For example, the closed25

loop sensor can be positioned on a laptop near the keyboard as illustrated in FIG. 2. The
base 20 of the laptop is illustrated having a keyboard 22, a touch pad (or touch screen) 24,

and a closed-loop sensor 26. Alternative positions include positioning the closed-loop
sensor on or connecting it to a conventional computer or keyboard. FIG. 3 illustrates the
closed-loop sensor 26 disposed on a conventional pointing device 28. Conventional pointing
30

device 28 may have other features, such as left click or right click buttons, which are not
shown.
The closed-loop sensor of the present invention can also be implemented as a standalone device, or as a separate device to be used with another pointing input device such as a

touch pad or a pointing stick. The closed-loop sensor of the present invention can either use

35

its own resources, such as a processor and sensors, or share its resources with another
device. The closed-loop sensor can be a capacitive, resistive, or inductive touch or
proximity (pen or stylus) sensor. A capacitive sensor is preferred, and is illustrated herein.
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The closed-loop sensor can be implemented as a stand-alone sensor, which can then
be used as a replacement for one or more knobs, sliders, or switches on any piece of
electronic equipment. In some cases, it might be desirable to provide visual feedback

indicating the "current" setting of the virtual knob, such as a ring of light emitting diodes
(LEDs) surrounding the closed-loop region. An Etch-a-Sketch= type of electronic toy can
10

be implemented using a single position detector with two closed-loop sensors or two
position detectors with one closed-loop sensor each. Many other toys and consumer
appliances currently have knobs used in similar ways that can benefit from the present
invention.
The closed-loop sensor can have electrodes (or sensor pads) that are of various

15

shapes and designs (e.g., a simple wedge or pie-shape, a lightning-bolt or zigzag design,
triangles, outward spirals, or the like) configured in a closed-loop path. A closed-loop
sensor 30 having wedge-shaped electrodes is illustrated in FIG. 4, while a closed-loop sensor

34 having lightning-bolt-shaped electrodes is illustrated in FIG. 5. The sensor pattern can be
designed so that it can have continuous interpolation between the electrodes. The sensor
20

pattern can also be designed so that the electrodes interleave between each other to help

spread the user's input signal over several electrodes.

FIG. 4 illustrates the wedge- (or pie-) shaped electrodes in a closed-loop capacitive
sensor 30. When an input object (or finger or pointer or stylus or pen or implement) is over
first electrode 31, only the first electrode 31 senses the largest change in capacitance. As the

25

input object moves clockwise toward electrodes 32 and 33, the signal registered by first
electrode 31 gradually decreases as the signal registered by the second electrode 32

increases; as the input object continues to move further clockwise toward third electrode 33,
the first electrode 31 signal drops off and the third electrode 33 starts picking up the input

object, and so on. By processing the electrode signals in largely the same way as for a
30

standard linear sensor, and taking into account that there is no true beginning or end to the
closed-loop sensor, the object position detector having the wedge sensor can interpolate the
input object's position accurately.

FIG. 5 illustrates the lightning-bolt-shaped electrodes in a closed-loop sensor 34.
The lightning-bolt design helps spread out the signal associated with an input object across
35

many electrodes by interleaving adjacent electrodes. The signals on a closed-loop sensor
with lightning-bolt shaped electrodes are spread out in such a way that the electrode closest
to the actual position of the input object has the largest signal, the nearby electrodes have the
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next largest signal, and the farther electrodes have small or negligible signals. However,
comparing a lighting-bolt sensor with a wedge sensor with a similar size and number of
electrodes, an input object on the lightning-bolt sensor will typically couple to more
electrodes than in the wedge sensor. This means that the lighting-bolt sensor will have more
information about the input object's position than a wedge sensor, and this effect helps

10

increase sensor resolution and accuracy m sensmg the input object's position. For best
results, the electrodes of the lightning bolt sensor need to be sufficiently jagged in shape
such that the input object on the sensor will always cover more than one electrode. The
interleaving nature of this electrode design means that the spacing from one electrode to the
next can be larger than in the wedge sensor while still providing similar resolution and

15

- ma y. The spacing from one electrode to the next with such an interdigitated electrode
design may even be considerably larger than the expected input object.

Another example is a closed-loop sensor 35 having triangle-shaped electrodes, as
illustrated in FIG. 6. In this case, the odd-numbered triangle-shaped electrodes (e.g. 37, 39)
are wider toward the outer edge of the closed-loop area and narrower toward the inner edge
20

of the closed-loop area, while the even-numbered triangle-shaped electrodes (e.g. 36, 38)
have the opposite positioning. To compute the input object's angular position around the
closed-loop sensor, the same interpolation algorithm used for other closed-loop sensors can
be used. As long as the input object is wide enough to cover at least two even-numbered
electrodes (e.g., 36, 38) and at least two odd-numbered electrodes (e.g., 37, 39),

25

interpolation to calculate position along the loop will mostly compensate for the difference
in the shapes of the even electrodes versus odd electrodes. To compute the input objects

radial position, or position between the inner and outer edges of the closed-loop sensor area,
the total capacitance CEVEN on the even-numbered electrodes and similarly the total
capacitance Copa of the odd-numbered electrodes should be calculated. The radial position
30

is given by Coco / (CEVE

ODD). If Only radial information is desired of the closed-loop

sensor, then only two distinct electrode sets are needed - all of the odd-numbered electrodes

can be electrically connected or ,,LJ together, and all of the even-numbered electrodes can

be electrically connected or wired together. The triangle design is also self-interpolating in
the radial position in that the odd-number electrodes (e.g., 37, 39) will naturally increase in
35

signal and the even-number electrodes (e.g. 36, 38) will naturally decrease in signal, when

the input object moves from the inner edge of the closed-loop sensor towards the outer edge
of the closed-loop sensor; these natural effects facilitate determination of the radial position.
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As shown in Figure 6, the odd-number electrodes (e.g., 37, 39) are larger in area than
the even-number electrodes (e.g., 36, 38). This means that the odd-number electrodes (e.g.,

37, 39) may produce a larger signal than the even-number electrodes (e.g., 36, 38) in
response to the same type of input and cause the simple Coco / (Cr>VEN

ODD) CRÎCUÎßÍÎOR Of

radial position to favor the outer edge. There are many ways to prevent the closed-loop
10

sensor 35 from biasing toward the outer edge when calculating radial position. For

ple,

the signals from either the odd-number electrodes (e.g., 37, 39), or the even-number
electrodes (e.g., 36, 38), or both, can be scaled based on size prior to calculating radial
position, or the radial position produced can be adjusted based on electrode sizes. This
unbalanced signal effect is due to having to accommodate the circular shape of closed-loop
15

sensor 35; for example, a linear sensor with triangular electrodes can easily have equally
sized triangular electrodes.

Rectangle-shaped electrodes 40, 41 can also be utinzed, as illustrated in FIG. 7 and
8, respectively. Another example is a closed-loop sensor 42 having triangle-shaped
electrodes that are rounded, similar to petals of a flower, as illustrated in FIG. 9. The design
20

shown in FIG. 9 is a method of reducing the unbalanced signal effect described above by
adjusting the triangle electrodes such that all of the electrodes are similar in size. Another

example of electrode shapes is shown by a closed-loop sensor 43 having spiral-shaped
electrodes, as illustrated in FIG. 10.
The closed-Ioop sensor generally utilizes sensor electrodes arranged along the shape
25

of a closed, or substantially closed, path (or loop). Several shapes may be used, although a
circular path is preferred. FIGS. 11 to 17 illustrate various shapes contemplated. The
shapes contemplated include a circle, an oval, a triangle, a square, a rectaugle, an ellipse, a

convex or concave polygon, a figure eight, a spiral, a complex mate-like path, and the like.
Other more complex paths are possible and might be more desirable or more appropriate in

30

some situations. In addition, the loop sensor can also be nonplanar; for example, it may be
arranged on the surface of a cylinder, a cone, a sphere, or other 3-D surface. Also, the loop
path may be defined for input objects of various sizes, perhaps as small as a pen tip and as
large as a hand.
It is desirable to communicate a definition of the loop path to the user. There are

35

several means possible to define the path of the closed-loop sensor including tactile guides
and physical constraints. As illustrated in FIGS. 18 and 20, a physical constraint in the form
of a depressed groove can be used to define the path on the closed-loop sensor. The
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depressed groove can be U-shaped 46, V-shaped 44, or some other cross-sectional shape.
FIG. 19 illustrates the use of a physical constraint in the form of a raised ridge 45, while
FIG. 21 illustrates the use of a physical constraint in the form of a bezel 48 to define the path
on the closed-loop sensor. Other tactile options are also contemplated, including a depressed
region, a cutout, a textured region, a tactile label (such as a label with embossing, stamping,

10

or raised printing), a rounded protrusion, and the like. The path can also be indicated in a
non-tactile manner, such as by LCD projections, non-tactile graphics printed on a label

covering the sensor or on the sensor housing, or a display associated with a transparent
closed-loop sensor. A tactile guide is preferred when practiced.

There are distinct advantages of having a tactile guide that help retain the input
15

object along the closed-loop path. Without such a guide, the input object tends to stray as
the user cannot track the loop perfectly, and especially as the user shifts attention between
keeping the input object within the loop and monitoring the resulting actions in response to
input along the loop. Even with methods to try to compensate for the deviation from the
defined loop (as discussed further herein), the resulting interface is not as user friendly or as

20

amenable to user control as a guide that help retain the input object. There are distinct
advantages to marking the loop path appropriately for the expected input object. For
example, if a finger is utilized, a groove designed to retain and guide the finger can be used.
If a stylus is utilized, a smaller groove can be used to retain the stylus. If a hand is utilized, a

larger groove can be used.
25

Multiple closed paths can be defined on a single input device, each of which controls
different features of the user interface. In this case, it is especially desirable to make the

location of each loop path readily apparent to the user by use of one of the above-mentioned
means, such as a bezel with multiple openings.
There are many ways of decoding the user's position along the path. The hardware
30

of the sensor may be designed, for example, with the loop path physically laid out in such a
way that the only coordinate reported to the host computer is already in the desired form.
Alternately, for some loop paths, X/Y coordinates on a traditional two-dimensional
sensor can be converted into polar coordinates (with the origin preferably located in the
center of the loop) and the angle component used as the user's position. Multiple closed

35

loops can be defined on a single two-dimensional position detector and resolved by

calculating multiple sets of polar coordinates with different origins and choosing the closed
loop yielding the smallest radial coordinate. More complicated path-based decoding can
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also be performed by dividing the path into geometrically simpler regions, and using various
methods designed to determine which region contains an input.
Once the user's position on the loop path is de ---7--ed using above-referenced

methods, this information can be used in many ways. Successive user locations can be
subtracted to decode motion direction or magnitude. This motion can, for example, be
10

converted into scrolling signals or keystrokes that the user interface can interpret.
In a preferred embodiment, this user motion is only interpreted in a relative manner.
That is, the absolute position of the input object in the loop path is insignificant. This can be
advantageous because it frees the user from having to target an exact starting position along
the loop. However, it may occasionally be useful to use this absolute position (i.e., an exact

15

starting point), for example, to indicate a starting value for a controlled parameter or to
indicate the desired parameter to be varied.

One of the user interface problems that can benefit from the present invention is
scrolling. To solve the scrolling problem, the motion of the user's position on the closedloop sensor is converted to signals (or instructions) that would cause the user interface to
20

scroll the currently viewed data in the corresponding direction. FIGS. 22 and 23 illustrate
the motions (illustrated by arrow 50) of an input object on a closed-loop sensor of an object

position detector 52 and the effect on a host device. For the purposes of this disclosure,
numeral 52 represents an object position detector. As disclosed herein, the object position
detector could be any shape.

25

As the input object moves on the closed loop sensor of the object position detector
52, a document on a computer screen 54, for example, is scrolled either up or down
depending upon the direction of the movement of the input object. For example, in the case
of FIG. 22, the counterclockwise motion shown by arrow 50 can

the document 54 to

be scrolled up as indicated by arrow 56, while FIG. 23 illustrates the scrolling of the
30

ds,s ,«- ut down as indicated by arrow 58 with a clockwise motion (shown by arrow 50) on
the closed-loop sensor of the object position detector 52.
Navigating through menus is also easier with the present invention. As illustrated in
FIG. 24, a motion either clockwise or counterclockwise (illustrated by arrow 60), on the
closed-loop sensor of the object position detector 62 would cause the drop down of menu

35

items 64 on, for example, a computer screen 66. For the purposes of this disclosure,
numeral 62 represents an object position detector. As disclosed herein, the object position
detector could be any shape. The simplest instance of this is to convert the relative position
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signal (or instruction) in such a way that the menu is navigated depth-first by sending
keystrokes or other messages understood by the graphical user interface (GUI) to indicate

intent to navigate a menu. One alternative solution for complex menus is to traverse only the
current menu hierarchy level by using the loop method of the closed-loop sensor, and a
separate mechanism to switch between levels in the menu. There are many applicable
10

mechanisms, including physical switches that the user presses, regions on the sensor where
the user can tap or draw a suggestive gesture, and the like.
It is possible to overload the user interface element controlled by the closed-loop
sensor using physical or virtual "shift" keys or switches, which is similar to the way that the
shift key on a keyboard overloads the meaning of the keys. For example, the system can be

15

configured so that unmodified traversal along the path would control scrolling of the current
application, but modified traversal by holding down a keyboard's "shift" key can control the

volume setting of the audio output. This can be accomplished with a single sensor by way
of mode switching, or by multiple sensors or regions of a single sensor, as will be illustrated

further herein.
20

This mode switching means, such as a "shift key" or other appropriate key, can cause
input on the closed-loop sensor of the object position detector 62 to traverse the menu

hierarchy orthogonal to the current level. FIG. 25 illustrates the activation of a "oLJt" key
68 combined with a motion (illustrated by arrow 60) on the closed-loop sensor of the object
position detector 62 to move through the menu items 64 on, for example, a computer - su
25

66. FIG. 25 illustrates the vertical movement (illustrated by arrow 74) through menus with

the shift key 68 activated, while FIG. 26 illustrates the horizontal movement (illustrated by
arrow 76) through horizontal menu items 72 with the shift key unactivated. It is also

possible to reverse the function of shift key 68, such that not depressing shift key 68 results
30

in vertical motion through the menu items 64, while depressing shift key 68 results in
horizontal movement between menu layers.
The closed-loop

r of the object position detector 62 also addresses the "deep

menu" problem by enabling the menu to be presented in flatter form on the computer screen

66. Studies have shown that humans are capable of using, and may even prefer to use,
menus in which the submenus are displayed in indented form (not shown). However, users

35

have traditionally had trouble with such menus since maneuvering down such a list may
require fine steering control of the cursor or multiple scrolling motions. The present

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invention, which allows infinite scrolling along a menu, enables the deeper menu to be
presented as a longer list, and the depth of the menu reduced.

A value setting control, such as a "spin control" or slider, can be varied according to
the user's input on a closed-loop sensor in a similar manner by sending keystrokes or other
messages understood by the user interface as indicating an attempt by the user to increment
10

or decrement the value of the control. FIG. 27 illustrates an example of a value setting
control that controls the volume settings. As illustrated in FIG. 27, a motion, either
clockwise or counterclockwise, (illustrated by arrow 80) on the closed-loop sensor of the
object position detector 82 would cause the setting of the volume control 84 to either
increase or decrease (as indicated by arrow 86) on, for example, a computer screen 66. For

15

the purposes of this disclosure, numeral 82 represents an object position detector. As
disclosed herein, the object position detector could be any shape.
-

For two-dimensional and three-dimensional graphical presentations, such as

computer aided drafting (CAD), solid modeling, or data visualization, the relative motion of

the user's input on the closed-loop sensor can be converted by the software directly into
20

translation, rotation, and/or scaling of the model or viewport.
Many user interface elements can benefit from the closed-loop sensor. Most can be

categorized as being similar to controls for scrolling, menus, or value setting controls. For
example, selection among icons on a "desktop" can be performed using this method, with a
means (such as a gesture on the sensor, a tap on the sensor, a button, or a key) provided for
25

launching the corresponding program once the user is satisfied with the selection. This task
can be considered analogous to navigating a menu.

Navigation along the "tab order" of the elements of a graphical user interface can be

performed with a closed-loop sensor. Similarly, navigation between multiple running
applications, multiple documents edited by the
30

t application, or multiple modes of a

particular application can be accomplished with this control.
As an alternative to a separate sensor with a defined path, a special mode can be
implemented on an existing touch pad-style pointing device to perform the same function as

the closed-loop sensor of the present disclosure. For example, a touch pad of a notebook
computer is primarily used for moving a pointer and selecting elements in the user interface.
35

A button, switch, or mode changing tap region on the touch pad can be defined to change the
mode of the touch pad so that it operates as a loop-scrolling device. The user would activate
this mode-switching control, and then move in an approximately closed loop path,
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¯

¯

preferably circular, on the touch pad. While this mode is selected, this motion is interpreted
as a scrolling action rather than as the typical pointing action.
Another mode switching method is possible if the closed-loop sensor can distinguish
the number of input objects present. Moving in a circle with two input objects (both input
objects moving in the same direction, as opposed to when the input objects move in opposite

10

directions or when one of the input objects does not move significantly) on the closed-loop
sensor, for example, can scroll through a set of data, while moving a single input object can
be interpreted as a pointing action. Due to the flexible nature of the closed-loop sensor,
other usage modalities are possible in combination with this fundamental mode of operation.

As stated above, the closed-loop sensor can also share the resources of a separate
15

touch pad or touch sensor. FIG. 28 illustrates the electrical leads 94 connecting the closedloop sensor electrodes 91 of a closed-loop sensor 90 with Y axis electrodes 93 (eight are
illustrated) of a touch pad 92. For the purposes of this disclosure, numeral 90 represents an
exemplary closed-loop sensor and numeral 92 represents an exemplary touch pad. One
skilled in the art would recognize that the touch pad 92 could be any shape, design or

20

configuration. The X axis electrodes of touch pad 92 are not shown. The leads 94 transmit
signals from the Y axis electrodes 93 or the closed-loop sensor electrodes 91, or both, to the
Y axis sensor inputs (not shown) of the processor (not shown). Additional leads (not shown)
connect the X axis electrodes (not shown) to the X axis sensor inputs (not shown). When an

input object touches the touch pad 92, the input results in changes in the signals of both the
25

Y sensor inputs and the X sensor inputs. In contrast, when an input object touches the
closed-loop sensor 90, the input is read by the electrodes as changes in the Y sensor inputs
only. By checking if the X axis signals have changed, the host system can distinguish

between user input on the touch pad 92 and the closed loop sensor 90. If desired, the X
sensor inputs can be connected to the closed-loop sensor instead of the Y sensor inputs.

30

Alternatively, additional closed-loop sensors can also be disposed and electrically connected
to the X sensor inputs of the touch pad.
As illustrated in FIG. 29, one axis of electrodes 95 of a touch pad 92 can support

more than one closed-loop sensor. Arrow 96 indicates the potential positioning of leads to a
first closed-loop sensor that has six distinct electrodes, while arrow 98 indicates the potential
35

positioning of leads to a second closed-loop sensor.
FIG. 30 illustrates the ability to have several closed-loop sensors 90 working in
conjunction with a touch pad 92. The leads connecting the electrodes of four separate
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closed-loop sensors 90 to the electrodes of a single touch pad 92 are illustrated. As shown
by closed-loop sensors 90, if absolute position information is not necessary, and only
relative motion is needed, the electrodes of the closed-loop sensor can be laid out as
repeating pattems of subsets of three or more sensor electrodes. When the same subsets are
repeated multiple times in each closed-loop sensor, the sensor signals cannot be used to

10

determine which of the subsets is interacting with the input object. However, the position of
the input object can be determined within the subset and, if the subset is large enough such
that the input object will not move beyond the subset before the next data sample is taken,
relative position of the input object can be determined between consecutive positions and
compared to calculate motion of the input object.

15

Repeated subsets of electrodes are especially useful if the closed-loop sensor is large,
since each electrode in the repeated pattern can remain small to retain adequate resolution
without increasing the complexity of sensor circuitry significantly. Repeated subsets are
also useful if fine resolution is needed as many more sensor electrodes can be put in a small
distance to increase the resolution without increasing the complexity of sensor circuitry.

20

Repeated electrodes are also useful if it is desirable to control many relative position closedloop sensors with a single integrated circuit, because it reduces the number of distinct sensor
inputs (or input lines) that need to be supported in the circuit. Additional methods can be
used to further decrease the number of distinct sensor inputs, such as multiplexing the

sensing circuitry across multiple sensor electrodes.

25

FIG. 31 illustrates another way that one Cartesian touch pad can be used to control a
plurality of closed-loop sensors. Each of the closed-loop sensors can be linked to the same
set of sensor inputs that is associated with the first axis of the Cartesian touch pad. Thus, the
corresponding electrodes on each closed-loop sensor will be linked to the same sensor input.
Each of the closed-loop sensors can also be linked to distinct ones of the electrodes of the

30

second axis of the Cartesian touch pad. This can be accomplished by running a separate

"indicator" sense electrode along the loop path of each closed-loop

and linking these

indicator electrodes to distinct sensor inputs on the second axis. The indicator electrode can
be located anywhere near the closed loop, and of any shape, as long as it will indicate user

input when the user interacts with the relevant closed loop.
35

With indicator electrodes linked to the sensor inputs of the second axis of the

Cartesian touch pad, if the signals from the sensor inputs of the second axis are similar to
that expected when the Cartesian touch pad is being used, then the host device can determine
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that the Cartesian touch pad is being used. For example, an input object on a typical
capacitive touch pad causes the capacitance registered by the sensor inputs to change in a

characteristic manner; the sensor inputs associated with the electrodes closest to the input
object indicate the greatest change in capacitance; the sensor inputs associated with
electrodes further from the input object indicate smaller changes in capacitance; the sensor

10

inputs associated with electrodes furthest from the input object indicate the smallest changes.
Thus, the configuration above in which indicator electrodes are linked to the second
axis can indicate when a closed-loop sensor is being used. For example, a user placing an
input object on a closed-loop sensor with an indicator electrode coupled to a touch pad will
cause the sensor input associated with the indicator electrode to indicate a large change in

15

capacitance. However, the input object will not cause the sensor inputs associated with
adjacent electrodes of the second axis to vary in the characteristic pattern described above

that is associated with an input object on the touch pad. Thus, the host device can determine
that a closed-loop sensor is being used and act accordingly. In one embodiment, the
indicator electrodes are laid out and shielded such that minimal capacitive coupling occurs
20

between the input object and the indicator electrodes of the closed-loop sensors not being

touched by the input object; with this embodiment, significant signal on the sensor inputs of
the second axis comes from only the

r input associated with the indicator electrode of

the closed-loop sensor being touched, and negligible signal comes on the other sensor inputs

of the second axis. Signals from the first axis would indicate position and motion on the

25

closed-loop sensor, while signals from the second axis would indicate which closed-loop
sensor is being used.
FIG. 31 illustrates two closed-loop sensors 90 electrically connected with a touch pad

92. When an input object touches the touch pad 92, the input is read by the sensor inputs as
changes in adjacent ones of second axis ,ar inputs (demarked by x's and represented by

30

numeral 103 in FIG. 32). In contrast, when an input object touches the closed-loop sensor
90, the input is read as changes (demarked by o's and represented by numeral 101 in FIG

32) in the sensor input associated with indicator electrode 100 (represented by sensor input 1
in FIG. 32). This enables the processor (not shown) to determine which device is being
utilized for the present function. Although two closed-loop sensors 90 are illustrated,
35

several other closed-loop sensors may also be connected to the touch pad 92 and can also

have indicator electrodes. These indicator electrodes may be connected at any one of the
positions illustrated by arrows 102.
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In another embodiment, control electronics designed for a Cartesian touch pad can
be used in the manner of FIG. 31, but without an actual touch pad sensor, as a simple costeffective way to implement a collection of closed-loop sensors.
In the case that multiple closed-loop sensors are being operated at once, or closedloop sensors and the touch pad are being operated simultaneously, the characteristic signal

10

shape (such as spikes of large changes in capacitance on some sensor inputs and not others)
can be used to indicate which closed-loop sensors are being used and the signals can be
decomposed appropriately. In cases where the host device cannot determine which sensors
are being used, then another indication of which

are used can be indicated through

key presses, button clicks, gestures on the touch pad, or other input. This would enable the
15

host device to extract useful information about which sensor is being touched from the

superimposed signals, or the system can use this information to reject simultaneous input on
multiple sensors.
In addition to using indicator loop electrodes, multiplexing inputs and outputs in time
can also be used to determine which of a plurality of closed-loop sensors have caused an
20

input. Other methods of multiplexing over time or over separate sensor inputs and driving
circuitry are also viable.
The present invention can have an inactive region in the center of the loop path that

comprises a protrusion, a depression, or a surface in the same plane as the sensor.
Alternatively, the closed-loop sensor can also have a physical button, or multiple buttons, in

25

the center. The closed-loop sensor can have a hole for a physical button in the center or the
center can be one or more touch sensitive zones (or activation zones), which can also be
used to emulate one or more buttons. The closed-loop sensor can have a pointing stick,
track ball, small touch pad, or other input device in the center. The closed-loop sensor can
have one or more physical buttons beneath it that are activated by pressing on the closed-

30

loop sensor.

FIG. 33 illustrates a top view of an exemplary closed-loop sensor 110 having a
pointing stick 112 disposed in the center of a bezel of-the closed-loop sensor 110. For the
purposes of this disclosure, numeral 112 represents an exemplary pointing stick. One skilled
in the art would recognize that the pointing stick 112 could be any shape, design or
35

configuration. FIG. 34 illustrates a side view of the cross-section of the closed-loop sensor

110. The pointing stick 112 is disposed in the center of the closed-loop sensor 110
surrounded by an interior portion 114 of the bezel. The loop path 116 is defined by interior
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portion 114 and also by an exterior portion 115 of the bezel. In one application of the
arrangement in FIG. 33, pointing stick 112 can serve as the pointing device for a laptop

computer, and the closed-loop sensor 110 can serve as the scrolling device.
FIG. 35 illustrates the lightning-bolt design sensor 120 having an interior opening
122 for the installation of, for example, a pointing stick, and four exterior regions 124 that
10

can be touch sensitive zones (or activation zones) that emulate buttons. If desired, the touch
sensitive zones can also be used to estimate pressure of contact if the input object is similar
to a finger in its tendency to spread out and cover a greater area of the sensor with increased
contact pressure. This additional information can be used to increase the functionality of the

sensor. The closed-loop sensor can detect taps, presses, and other gestures, which can be
15

used to control general-purpose input/output (GPIO) pins or reported in a data packet.
Multiple closed-loop sensors can be implemented as a set of nested closed-loop
sensors defined on a single position detector, or on multiple position detectors, with each
closed-loop sensor controlling a different feature of the user interface. Determining the
angular 6 position of the input object in such a set of nested closed-loop sensors is the same

20

as in determining the angular 0 position of the input object in a single closed-loop sensor.
These nested closed-loop sensors can act as independent input devices. They can also be
used together as parts of one control - such as in a vernier-type control in which outer loops
are associated with coarser control and inner loops are associated with finer adjustment.
Nested closed-loop sensors can also be used together to generate a one-and-a-half

25

dimensional or a two-dimensional input device. For example, a set of nested closed-loop
sensor can be formed from a concentric set of circular closed-loop sensors having varying
radii. In the one-and-a-half dimensional version, the position detector monitors which
closed-loop sensor has the strongest input signal to make a gross estimate of the input object

position.
30

In the two-dimensional version, signals from the set of nested closed-loop sensors are
interpolated to more a

tely generate a radial r position of the input object. Algorithms

similar to those used to calculate linear coordinates can be used for calculating the radial r
coordinates. Depending on the design of the radial sensor electrodes, scaling or weighting

of individual electrode signals may be necessary to ac
35

odate for the larger or more

numerous sensor electrodes in the loops farther away from the center of the nested sensors.
However, after such scaling (if necessary), conventional methods for interpolation to
estimate position and for estimating motion can be used. Since the radial r position is
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known to a finer resolution than the number of concentric closed-loop sensors in the set of
nested sensors, the r information can be used to enable the set of nested sensors to emulate

more closed-loop sensors than the actual number of closed-loop sensors physically in the
nested set. The preceding applications of buttons, keys, pointing sticks, touch screens, touch
sensitive zones, and the like, with a single closed-loop sensor can also be applied to a
10

position detector having multiple closed-loop sensors.
FIG. 36 illustrates an object position detector 130 having four closed-loop sensors to
vary the settings of audio controls. Although four separate closed-loop sensors are shown,
any number of closed-loop sensors can be utilized. Using the volume control closed-loop
sensor 132 as an example, the motions (illustrated by -- 134) of an input object on the

15

volume control closed-loop sensor 132 will cause the volume of the audio system to either
or decrease. Likewise, other closed-loop sensors on object position detector 130
can be used for balance and the levels of treble and bass for an audio system.
The multiple closed-loop system can be applied in alternative ways. FIG. 37

illustrates another object position detector 140 for an audio system having two sets of nested
20

sensors (142 and 144) consisting of concentric circles of two closed-loop sensors. Each of
the two sets of nested sensors (142 and 144) has separate closed-loop sensors to control

separate functions for the audio system. For example, nested set of sensors 142 has a first
closed-loop sensor 146 for bass and a m ULtd closed-loop sensor 148 for treble. Other
nested closed-loop sensor shapes are contemplated in addition to concentric circles.
25

Another altemative multiple closed-loop system is an object position detector 150 for
an audio system having four closed-loop sensors disposed in concentric circles (or other

appropriate shapes) as illustrated in FIG. 38. The four separate closed-loop sensors each
control a separate function in the audio system. For example, closed-loop sensor 152
controls volume, closed-loop sensor 154 controls balance, closed-loop sensor 156 controls
30

treble, and closed-loop sensor 158 controls bass.

Position algorithms can be used to calculate the position along a closed loop, which
can be expressed as angular coordinates for roughly circular closed-loop sensor designs, of
an input object, including a quadratic fitting method, a centroid interpolation method, a
trigonometric weighting method, and a quasi-trigonometric weighting method. When the
35

closed-loop sensor is implemented as a capacitive sensor, the capacitance measurements

from the sensor electrodes are preferably combined using an interpolation algorithm for
greater precision.
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¯¯ ¯¯

A preferred interpolation method is quadratic fitting, as illustrated in FIG. 39. This
method typically involves three steps. In the first "peak detection" step, the electrode with
largest capacitance measurement is determined to be electrode number i, where the N
electrodes are numbered from 0 to N-1. The number i is an initial, coarse estimate of the
input object position. The capacitance measurements are normally made against a non-zero

10

background capacitance on each electrode. This background (no input object) capacitance
arises from a number of factors such as chip pin capacitance and circuit board ground plane
capacitance. Many of these effects vary from sensor to sensor and vary over time, so it is
preferable to use a dynamic calibration algorithm to subtract out the baseline. First, the
capacitances C'(j) of all the electrodes 0 < j < N are measured at a time when no input object

15

is present; and stored in a table Co(j). Then, when an input object is present, the electrode
input object capacitance measurement, C(j), is preferably computed from the capacitances of

all of the electrodes C'(j) as C(j) = C'(j) - Co(j).
In the second "quadratic fitting" step, the three capacitance measurements from the
three adjacent electrodes numbered i-1, i, and i+1 are fitted to an inverted parabola, as is
20

illustrated in the graph in FIG. 40. The three (x, y) coordinate points (i-1, C(i-1)), (i, C(i)),
and (i+1,C(i+1)) define a unique parabola or quadratic function by well-known
mathematical principles. In a closed-loop sensor, the electrode numbering is taken modulo

N so that electrodes 0 and N-1 are adjacent. Once the parameters of the parabola fitting the
three electrodes are det, mined, the true mathematical center point X (indicated by arrow
25

172) of this parabola is calculated. This will be a fractional number near the value i. The

number X can be reduced modulo Nif necessary.
In the third, optional, "adjustment" step, the value X is passed through a non-linear
function designed to compensate for any non-linearities due to non-idealities in the electrode
design. It is realized that no sensor pattern will produce a completely ideal result for any
30

particular interpolation algorithm. Therefore, the computed position will have some
"wobble" as the input object moves around the length of the sensor.
However, because the sensor electrode pattern is rotationally symmetric, this wobble
will repeat in equivalence to the spaces between the electrodes. The wobble will depend on
where the input object is between two electrodes, and not on which electrode the input

35

object is disposed. Mathematically, if the true input object position is X, and the interpolated
position is X, then X = w(X)) for some "wobble" function w(x). Because w(x) is periodic, the
position can be written in terms of its integer and fractional parts as X) = int(X,) + frac(X,),
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and the wobble can be expressed as X = int(X,) + w(frac(X,)). The nature of w(x) can be
determined theoretically or by experimental measurements; its inverse c(x) can then easily
be computed or approximated using well-known techniques in the art. Because c is the
inverse of w, the fmal computed position is X' = c(X) = c(w(Xy)) = X,, so that X ' is
compensated to reproduce the true input object position Xy. Because w(x) is a periodic

10

function, its inverse c(x) will also be periodic. Thus, the final computed position is
calculated as X' = int(X) + c(frac(X)) = int(X,) + c(w(frac(X,)) = int(X,) + frac(Xy) = Xy.
This analysis assumes 0 K w(x) < 1, which is not necessarily true; a somewhat more
elaborate analysis shows that the technique works for any invertible periodic function w(x).
It will be obvious to those skilled in the art that an analogous adjustment step can be used

15

with any interpolation method on circular sensors.
The resulting position X', falling in the range 0 E X' < N, represents the angular
position of the input object in units of electrodes. The number X' can be multiplied by
360/N to convert it into an angular position in degrees.
An alternate interpolation method, often used in the art, is centroid interpolation, as

20

illustrated in FIG. 41. This method computes the mathematical centroid of the curve of
capacitance measurements and is adapted to closed-loop sensors by locating the peak
electrode number i, and then rotating the coordinate system by renumbering each electrode j

to (j - i + N/2) modulo N. This moves peak electrode i to the approximate center of the
sensor for purposes of the centroid calculation. After the centroid calculation produces a

25

position X, the -, -- rotation is applied, X' = (X + i - N/2) modulo N, to produce the final
angular input object position.
A second way to adapt the centroid method is to use trigonometric weights, as

illustrated in FIG. 42.

In this method, a numerator N is computed as N =

sum(sin(i*2*pi/N)*C(i)) and a denominator D is computed as D = sum(cos(i*2*pi/N)*C(i)),
30

where C(i) is the capacitance measurements of the N electrodes and i ranges from 0 to N-1 in

the sums.

The arctangent atan(N/D) then yields the desired input object position.

Preferably, a four-quadrant arctangent, commonly written atan2(N,D), is used to obtain an

angular position over the full circle. The sine and cosine weight factors are constants that
can be pre-computed and tabulated. Because the sums N and D are linear in C(i), it is

35

possible to distribute out the baseline subtraction C(i) = C'(i) - Co (i) to become a simple

subtraction of baseline sums No and Do. It may be preferable to use the trigonometric

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method when memory resources are too limited to store a full set of baseline capacitance
values.
A useful generalization of the above method is to use a quasi-trigonometric
weighting method, as illustrated in FIG. 43. In substitution of standard sine, cosine, and
arctangent trigonometric functions, other periodic functions fs, and fc,, such as triangle

10

waves, and corresponding inverse function f,(fs, fc), can be used. In the case of triangle
waves, some loss of resolution is traded for greater linearity and simpler math calculations.
The primary cause of this loss in resolution is due to the discontinuities in the triangle wave
that generates discontinuities in the interpolation.
A loop path that inherently closes on itself poses an interesting challenge in

15

determining motion from the positional data from the sensor. If data is sampled at discrete
times, then the change in position at two different times can have occurred via two different
directions. The method for determining motion for a closed-loop sensor is described as

follows and is illustrated in FIG. 44.
20

After each sampling period, the input object position NewPos is calculated and it is
determined whether an input object (e.g., finger, stylus, pen, implement, or other input
object) is or is not present on the sensor. If the input object was not on the sensor during the
previous sample, NewPos is copied into OldPos. If an input object is present, the following

method is completed. Because the sensor is a closed loop, there are two paths an input
object can take between any two points on the sensor. For example, if the first position
25

(OldPos) is at 0 degrees and the second position (NewPos) is at 90 degrees, then the input
object can have traveled 90 degrees from 0, 1, 2, ... , 88, 89, to 90 or the input object can

have traveled 270 degrees from 0, 359, 358, ... , 92, 91, to 90. To resolve this, the
assumption is made that the input object cannot travel more than 180 degrees around the

sensor between two consecutive samples. To calculate motion, OldPos is subtracted from
30

NewPos to determine the amount of motion between the two samples (Motion = NewPos OldPos). If the resulting Motion is 180 degrees or more, the assumption is that the input
object must have traveled the other direction,.so 360 degrees is subtracted from Motion.

Likewise, if the resulting Motion is less than -180 degrees, the assumption is that the input
object must have traveled in the opposite direction, so 360 degrees is added to Motion. The
35

"signed" modulo 360 of the result is thus taken such that the ultimate result of this motion
calculation from one sample to the next, is constrained to, for example, -180 £Motion <180
degrees around the sensor. The sign of Motion gives the direction of travel and the absolute
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value of Motion gives the magnitude or distance of travel. In all cases, the algorithm
completes by copying NewPos onto OldPos.
This algorithm of det- ----°--I--g motion, in which the input object is assumed to travel
an angle of -180 & Motion < 180 degrees between two consecutive samples, can be
generalized to accommodate different sampling rates and shapes or sizes of the loop. For

10

alternate shapes or sizes of closed-loop sensors, appropriate assumptions of a Luum angle,
minimum angle, or ma/,ws distance of travel can be made based on the closed-loop path
layout and the sampling period. In the case of very long sampling periods or very small loop
paths, when the maximum angle, minimum angle, or distance of travel is no longer sufficient
for determining the path of travel of the object between two samples, then an assumption can

15

be made about the more likely path (such as that the shorter path is more likely) or additional

information can be used (such as using history of motion in the form of three or more
samples to estimate the direction of travel).

The motion information output of this closed-loop sensor can be implemented in
many ways and contain various amounts of information, including absolute positions or

20

relative positions (i.e., motions). The motion output can also be used to emulate a physical
wheel encoder and output two-bit gray code (sometimes called "quadrature states"), in

which case the closed-loop sensor can be added to any existing device which accepts two-bit
gray code with no modification to the original device's electronics.
When using a closed-loop sensor implemented on a two-dimensional touch sensor
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having both radial and circular -"^ electrodes but without a physical constraint (or tactile

guide) defining the closed-loop path, it is possible that the input object will gradually move
out of the defined loop path. This may result in a variable scaling of the distance traveled to
angular velocity, depending on the location of the motion with respect to the center of the
motion, which may result in a calculated magnitude of input significantly different from that
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intended by the user. For example, small motions near the center of the defined loop path
map to larger angular velocities than the same small motions near the periphery of the loop

path. Users are typically more able to control the absolute distance traveled of the input
object than the angle traveled by the input object relative to a defined center. Thus, for an

input, in which the distance from the center is not useful, such as scrolling along a page or
35

controlling the volume, users typically expect the output to be mapped to the distance
traveled rather than to the angle, and may prefer small motions anywhere in the loop path to
generate similar outputs.
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Therefore, in the case where the user's input object is not physically constrained to a
particular closed-loop path, some adjustment is desirable in the angular speed due to the user
wandering closer and farther from the center point. If no adjustment were completed,
positions closer to the center point would cause more angular change for a given amount of

motion, which is not desirable from a human-factors point of view. Several adjustments are
10

possible, including simply scaling the angular speed by 1/R, as well as more complicated
and error prone scaling mechanisms, such as varying the center point to compensate for the
estimated user deviation from the center of the loop path. Scaling the angular speed by 1/R
involves dividing the angular speed by R (the radius from the center) of the system such that
small motions near the center will not result in large outputs.

15

Another method is to use the angular component solely to determine the sign of the
traversal along the closed-loop path, and calculate the speed based only on the absolute
motion of the object, as illustrated in FIG. 45. For example, given two consecutive points
sampled from the closed-loop sensor, the straight-line distance is calculated between these

two points (with an approximation to the Pythagorean Theorem or equivalent polar
20

coordinate equations). Additionally, the angular positions corresponding to these two points
along the closed-loop path are calculated by one of the means previously discussed. The
angle of the second point is subtracted from the angle of the first point, and the sign of this
result is used to indicate the direction of motion, while the absolute distance is used to
indicate the amount of motion. This results in a more natural feeling correspondence

25

between the motion of the user's input object and the corresponding variation in the
controlled parameter (e.g., scrolling distance, menu traversal, or setting value).
In the case that the closed-loop sensor is not circular or substantially circular, the
algorithms used to calculate position for a circular sensor could still be used to estimate an

input object's position. In this case, the algorithm will indicate where the input object(s)
30

is(are) in the closed loop of the closed-loop sensor, and software can decode the exact

location based on knowledge of the local electrode design. For example, a closed-loop
sensor having a rectangular loop with rounded corners can have software that can
differentiate the signals generated by an object very near, or on, the corners versus the
signals generated by an object along a linear portion of the rectangle. The previously

35

discussed algorithms can generate this information and compensate.
The present disclosure discloses several advantages. A touch sensor is disclosed
having a closed-loop sensor, or a designated loop path along which a user can move an input
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object, where the action of scrolling/selecting/varying is controlled by the motion of the
input object along the loop path. For example, the direction, the distance of travel, or the

spéed of the input object can provide the control input. The closed-loop sensor also has the
additional advantage of not being limited by mechanical design or human anatomy in
enabling a user to maneuver through a document, through menus, or along a range of values
10

for a control. For example, a user can easily move an input object around a closed-loop
sensor in a continuous ------er, and draw a plurality of loops within the sensor area, with the
number of loops drawn limited only by the fatigue of the user or the functional life of the
sensor.
The present invention has many uses, incluc.ling for scrolling, moving through a

15

menu, A/V uses (fast forward, rewind, zoom, pan, volume, balance, etc.), twodimensional/three dimensional data presentation, selection, drag-and-drop, cursor control,

and the like. Many applications have application-specific elements that can benefit from the
type of control achieved by using the closed-loop sensor of the present invention. For
example, a game can benefit from having a continuously variable control that can be used as

20

a steering wheel, a dial, or other control that indicates direction and magnitude of motion.
Another example is for use with a CAD program that allows the user to rotateltranslatelscale

the viewpoint of a model or to vary the color of an element smoothly. A further example is
a text editor, which can benefit from a smooth and continuously varying input to control the.

zoom level of its text. In general, any application p
25

ter or control that needs to vary

over a large range of possible values can benefit from the present invention. Physical
processes (e.g., to control the position of a platform, the speed of a motor, the temperature or
lighting in a compartment, and the like) can also benefit from the use of closed-loop sensors.
The closed-loop sensor of the present disclosure frees users from targeting tasks or
from remembering complex combinations of controls by allowing designers of applications

30

or operating systems to reduce scroll bars and other similar display controls to mere

indicators of the current scrolled position or control value. If scroll bars and similar display
controls can be reduced to mere indicators, their size can be reduced and their positions at
the edge of the screen, edge of a window, or other specific location on the screen or window
will consume negligible space. Additionally, the freedom offered by reducing scroll bars

35

and similar display controls might allow menus to be less hierarchical, which further reduces
control and display complexity.

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° ~

~

~¯

The manufacturing cost and complexity of a host system can be reduced by using a
single solid state sensor with multiple closed loops to replace many of the various controls
currently present on such systems. The manufacturing cost and complexity of incorporating
closed-loop sensors into a host system can also be reduced by integrating the closed-loop
sensor with existing object position sensors (e.g. touch pads and touch screens) and taking

10

advantage of existing sensor inputs to the electronics of the existing position sensor.
Portions of a general-purpose position sensor, such as the sensor regions, the electronics, and
the firmware or driver of the general-purpose position sensor, can be reused with closedloop sensors, which can provide further savings in space and money.
Additionally, the solid-state nature of capacitive and inductive closed-loop sensors

15

makes them more reliable and durable.

Such sensors can be sealed and used in

environments where knobs and other physical controls are impractical. The present
invention can also be made smaller than knobs or other physical controls, and requires very
little space and can be custom made to almost any size. Additionally, the operation of the
sensor.has low power requirements, making it ideal for portable notebook computers,
20

personal digital assistants (PDAs), and personal entertainment devices.

The closed-loop sensor can also be used to provide additional information that a
knob or scroll bar would not, such as the size of the contact between the object on the s

and the sensor itself. Additionally, some closed-loop sensors may be able to distinguish
between a finger and a pen, or indicate some other quality or orientation of the input object.
25

This information can further be used to increase the functionality of the controller through

"gestures" on the closed-loop sensor. For example, the speed or range of scrolling or display
adjustment can be adjusted as a function of the speed of the input object's motion or the
distance traveled by the input object. Additional gestures, such as tapping, executing
predefined motion patterns, having a stationary input object and a moving input object
30

simultaneously, or moving two input objects in two directions along the loop of the sensor,
can indicate different actions to the host device. The starting point of contact of the input
object to the host- device program for the input can also be used. For

ample, a motion

starting from a first region of the sensor and progressing in a first direction can indicate
panning of the display, while motion starting from the same first region and progressing in a

35

second direction can indicate zooming of the display. Meanwhile, a motion starting from a
second region can indicate a desire to scroll horizontally, and the direction of motion can

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indicate the direction of scroll. This can be extrapolated to additional regions that map to
additional functions.
While the invention has been described with reference to an exemplary embodiment,
it will be understood by those skilled in the art that various changes may be made and
equivalents may be substituted for elements thereof without departing from the scope of the

10

present invention. In addition, many modifications may be made to adapt a particular
situation or material to the teachings without departing from the essential scope thereof.

Therefore, it is intended that the invention not be limited to the particular embodiments
disclosed as the best mode contemplated for carrying out the present invention, but that the

present invention will include all embodiments falling within the scope of the claims.

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