(12)
`
`United States Patent
`Shaw et al.
`
`(10) Patent N0.:
`45 Date of Patent:
`
`US 6,587,093 B1
`Jul. 1 2003
`
`a
`
`US006587093B1
`
`(54) CAPACITIVE MOUSE
`
`3,296,522 A
`
`1/1967 Wolfendale
`
`(75) Inventors: Scott J. Shaw, Fremont, CA (US);
`Shawn B Day’ San Jose’ CA (Us);
`Raymond A. Trent, Jr., San Jose, CA
`(Us); David W- Gillesple’ _Los Gatos’
`CA(U$);AI1dreW M- Errlllgt?ll,
`Milpitas, CA (US)
`
`(List COIlIiIllled On neXt page.)
`FOREIGN PATENT DOCUMENTS
`
`EP
`JP
`
`0 226 716 A2
`03-202774 A
`
`7/1987
`9/1991
`
`.......... .. G01D/5/24
`......... .. G01P/3/483
`
`OTHER PUBLICATIONS
`
`K. Hinkley et al., “Touch—Sensing Input Device”, ACM
`CHI’99 Conference on Human Factors in Computing Sys
`[ems’ pp 223_230, May 1999
`
`Primary Examiner—Steven Saras
`Assistant Examiner—Paul Bell
`(74) Attorney, Agent, or Firm—Sierra Patent Group, Ltd.
`(57)
`ABSTRACT
`
`A pointing device some or all of Whose elements are made
`from capacitive sensors. Such elements may include a rotary
`motion detector Which includes a rotating member and a
`plurality of ?Xed capacitive detecting members; a rolling
`ball With patterned conductive surface and a plurality of
`?xed Capacitl"? detefzting members; Capacitive touch Sen‘
`sors or capacitive switches to serve as mouse buttons; and a
`scrolling Wheel, knob, or touch surface built from capacitive
`sensors, Thepointing device further includes a capacitance
`measuring circuit and processor to measure variations of
`capacitance on the various capacitive elements and to deter
`mine the movement of and other activations of the mouse.
`
`_
`(73) Ass1gnee: Synaptics Incorporated, San Jose, CA
`(Us)
`_
`_
`_
`_
`Sub]ect' to any disclaimer, the term of this
`patent is extended or adJusted under 35
`U.S.C.154b b 0d .
`( ) y
`ays
`
`*
`
`_
`) Notice:
`
`(
`
`(21) Appl' NO‘: 09/705’593
`(22) Filed:
`Nov. 3, 2000
`
`_ Relatul Uis- Application Data
`_
`(60) PTOVlSlOnal apphcatlon N°~ 60/163535: ?led on N°V~ 4:
`1999'
`(51) Int. Cl.7 ......................... .. G09G 5/08; G01R 27/26
`(52) US. Cl. ...................................... .. 345/163; 324/660
`(58) Field of Search ............................... .. 345/156, 157,
`345/163, 164, 167, 173, 174, 184; 341/20,
`22, 33; 178/1806, 1906; 324/658, 660,
`661, 662, 686725; ZOO/600; 340/870_37
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`3,214,663 A 10/1965 KreutZer ................... .. 318/138
`
`31 Claims, 10 Drawing Sheets
`
`302
`
`1304
`/
`
`312
`
`310
`
`Microsoft Ex. 1019
`Microsoft v. Philips - IPR2018-00025
`Page 1 of 21
`
`

`

`US 6,587,093 B1
`Page 2
`
`US. PATENT DOCUMENTS
`
`3,541,541 A 11/1970 Engelbart ................. .. 340/324
`3,873,916 A * 3/1975 Sterki ----------------------- -- 324/725
`3,938,113 A
`2/1976 Dobson 9t a1~
`3961318 A
`6/1976 Farrand er 91-
`4,221,975 A
`9/1980 Ledniczki et a1. ........ .. 307/116
`4,238,781 A 12/1980 Vercellotti et a1.
`340/870.37
`4,350,981 A
`9/1982 Tanaka et 91-
`4,364,035 A 12/1982 Kirsch ...................... .. 340/710
`4367385 A
`1/1983 Frflme -------- --
`4,404,560 A
`9/1983 wllllamsplr
`-~
`4,464,652 A
`8/1984 Lapson et a1. ............ .. 340/710
`4550221 A 10/1985 Mabusth
`4,631,524 A 12/1986 Brooke 91 a1~ --------- --
`4,720,698 A
`1/1988 Brooke et 211.
`4,843,387 A * 6/1989 Arai et a1. .
`4,862,752 A
`9/1989 HOYt ---- --
`4,870,302 A
`9/1989 Freeman-
`5,028,875 A * 7/1991 Peters
`5,122,785 A
`6/1992 Cooper ---- --
`5212452 A
`5/1993 Mayer et a1- -
`--
`5288993 A
`2/1994 Bidiville 9t 91-
`5313229 A
`5/1994 Gilligan er a1- ----------- -- 345/157
`5,414,420 A
`5/1995 Puckette
`5,530,455 A
`6/1996 Gillick et a1.
`
`5,583,541 A 12/1996 Solhjell
`5,644,127 A * 7/1997 Ohmae ..................... .. 345/164
`5,657,012 A
`8/1997 Tait
`5,691,646 A 11/1997 Sasaki ...................... .. 324/662
`5,736,865 A
`4/1998 Nelson et a1.
`324/660
`5,748,185 A
`5/1998 Stephan et a1. ........... .. 345/173
`5,805,144 A
`9/1998 Scholder et a1_
`5,861,875 A
`1/1999 Gerpheide
`5,867,111 A
`2/1999 Caldwell et a1. ............ .. 341/33
`5,872,408 A
`2/1999 Rakov ____________ u
`u 310/68 B
`5,880,411 A
`3/1999 Gillespie et a1. ..
`178/1801
`5,883,619 A
`3/1999 H0 et a1. ........... ..
`345/163
`5,907,152 A
`5/1999 Dandliker et a1_ ________ __ 250/221
`5,920,307 A
`7/1999 Blonder et 211.
`5,941,122 A
`8/1999 Nelson et a1. .............. .. 73/314
`5,943,052 A
`8/1999 Allen et a1_
`5,949,354 A
`9/1999 Chang
`5,963,197 A * 10/1999 Bacon et a1. ............. .. 345/163
`6,043,809 A * 3/2000 Holehan ...... ..
`345/168
`6,204,839 B1
`3/2001 Mato, Jr. ..... ..
`345/168
`6,211,878 B1 * 4/2001 Cheng et a1. ..
`345/169
`6,219,037 B1
`4/2001 Lee ................ ..
`.345/167
`6,449,853 B1
`9/2002 Brueggemann
`33/1 PT
`6,492,911 B1
`12/2002 NetZer ................. .. 340/870.37
`
`* cited by examiner
`
`Microsoft Ex. 1019
`Microsoft v. Philips - IPR2018-00025
`Page 2 of 21
`
`

`

`U.S. Patent
`
`Jul. 1, 2003
`
`Sheet 1 0f 10
`
`US 6,587,093 B1
`
`/ //?\
`
`r
`\
`
`118
`
`Fig. 1A
`(PRIOR ART)
`
`Fig. 1B
`(PRIOR ART)
`
`202
`
`1204
`/
`
`208
`
`214
`
`210
`
`Flg. 2A
`(PRIOR ART)
`
`Microsoft Ex. 1019
`Microsoft v. Philips - IPR2018-00025
`Page 3 of 21
`
`

`

`U.S. Patent
`
`Jul. 1, 2003
`
`Sheet 2 0f 10
`
`US 6,587,093 B1
`
`222 220 206
`
`226
`
`/\
`
`224
`
`228
`Fig. 2B
`(PRIOR ART)
`
`Detector 220
`
`302
`
`Microsoft Ex. 1019
`Microsoft v. Philips - IPR2018-00025
`Page 4 of 21
`
`

`

`U.S. Patent
`
`Jul. 1, 2003
`
`Sheet 3 0f 10
`
`US 6,587,093 B1
`
`322 320 306
`
`326 K
`
`324
`
`Fig. 38
`
`Plate 320 A
`
`Plate 322 m
`Fig. 3c
`
`Plate 320 I
`
`Plate 322 __ _____
`
`348
`
`__
`350
`_—Z_
`
`Fig. 3E
`
`Microsoft Ex. 1019
`Microsoft v. Philips - IPR2018-00025
`Page 5 of 21
`
`

`

`U.S. Patent
`
`Jul. 1, 2003
`
`Sheet 4 0f 10
`
`US 6,587,093 B1
`
`400
`
`402
`
`Microsoft Ex. 1019
`Microsoft v. Philips - IPR2018-00025
`Page 6 of 21
`
`

`

`U.S. Patent
`
`Jul. 1, 2003
`
`Sheet 5 0f 10
`
`US 6,587,093 B1
`
`71 0
`
`712
`
`702
`
`708
`
`706
`/
`
`!
`
`%704
`
`714
`¥___w—)
`700
`Fig. 7
`
`800
`\
`
`802
`/
`
`806
`/
`
`K E
`
`~804
`
`Fig. 8A
`820
`
`822
`/
`
`826
`‘——['—‘\‘828
`\830
`
`824
`
`Fig. 8B
`
`902
`
`900 \ A
`
`906
`\
`
`O
`
`904
`
`Microsoft Ex. 1019
`Microsoft v. Philips - IPR2018-00025
`Page 7 of 21
`
`

`

`U.S. Patent
`
`Jul. 1, 2003
`
`Sheet 6 0f 10
`
`US 6,587,093 B1
`
`1008
`
`1100
`
`\
`
`1102
`
`1106
`
`\ a???
`
`1002
`
`1006
`
`1012
`
`\O~1o04
`1010T§1008
`
`1014/
`
`Fig. 10
`
`Fig. 11A
`
`\4104
`
`1130
`
`Fig. 11C
`
`1100
`
`
`
`\ - Fig. 11D
`
`Microsoft Ex. 1019
`Microsoft v. Philips - IPR2018-00025
`Page 8 of 21
`
`

`

`U.S. Patent
`
`Jul. 1, 2003
`
`Sheet 7 0f 10
`
`US 6,587,093 B1
`
`1200
`
`1202
`
`\1208
`
`1202
`1200
`\ f‘5
`
`Fig. 12A
`
`1206
`\1208
`
`1204
`
`Fig. 128
`
`1202
`1200
`\ /—4a
`1204
`
`1206
`
`1210
`
`\1208
`Fig. 12C
`
`:1 c1 :1 1:1 1:
`
`1200
`1202
`\ /__%
`\1204
`Fig. 12E
`
`L1204
`
`1200 1212
`\ 1
`
`i202
`
`/ :1206
`
`\1208
`
`-
`F19. 12D
`
`Microsoft Ex. 1019
`Microsoft v. Philips - IPR2018-00025
`Page 9 of 21
`
`

`

`U.S. Patent
`
`Jul. 1, 2003
`
`Sheet 8 0f 10
`
`US 6,587,093 B1
`
`Fig. 13A
`
`1300
`
`-1302
`
`1304
`
`CD
`
`‘1304
`
`1308/
`
`Fig. 130
`
`Fig. 13D
`
`Microsoft Ex. 1019
`Microsoft v. Philips - IPR2018-00025
`Page 10 of 21
`
`

`

`U.S. Patent
`
`Jul. 1, 2003
`
`Sheet 9 0f 10
`
`US 6,587,093 B1
`
`1400
`
`\
`
`Fig. 14
`
`1700
`
`\
`
`1710
`/
`
`m x
`
`I
`1
`?/wos 1704
`1706
`
`)
`1702
`
`Fig. 17
`
`[100000
`
`1802/
`
`1804 /'
`
`1806 (J; Fig. 1a
`
`Microsoft Ex. 1019
`Microsoft v. Philips - IPR2018-00025
`Page 11 of 21
`
`

`

`U.S. Patent
`
`Jul. 1, 2003
`
`Sheet 10 of 10
`
`US 6,587,093 B1
`
`Time
`
`Capacitance
`
`1
`
`I
`
`l
`
`Third
`Button
`Signal
`
`Fig. 15
`
`Finger
`
`__
`
`+
`
`Motion
`
`0 ——
`
`Scroll
`
`+
`
`0 ———-—I—\J
`Flg. 16A
`
`Finger
`
`_
`
`+
`
`Motion
`
`0 —
`
`+
`
`800i
`
`0 _W
`Fig. 16B
`
`+
`
`Scroll
`
`0 M
`Fig. 16C
`
`Microsoft Ex. 1019
`Microsoft v. Philips - IPR2018-00025
`Page 12 of 21
`
`

`

`US 6,587,093 B1
`
`1
`CAPACITIVE MOUSE
`
`This application claims the bene?t of Ser. No. 60/163,
`635, ?led Nov. 4, 1999.
`This patent discloses a computer mouse implemented
`partially or Wholly using capacitive sensors.
`
`BACKGROUND OF THE INVENTION
`
`Pointing devices are an essential component of modern
`computers. One common type of pointing device is the
`mouse. Computer mice have been Well knoWn for many
`years. US. Pat. No. 3,541,541 to Engelbart discloses an
`early mouse implementation using either potentiometers or
`Wheels With conductive patterns to measure the motion. The
`conductive patterns on these Wheels are measured by direct
`electrical contact. Direct electrical contact to moving objects
`has many Well-knoWn disadvantages, such as increased
`friction, and Wear and corrosion of contacts.
`Modern mice folloW a plan similar to that of US. Pat. No.
`4,464,652 to Lapson et al, With a rolling ball mechanically
`coupled to optical rotary motion encoders. The mouse also
`includes one or several buttons that operate mechanical
`sWitches inside the mouse. Recent mouse designs also
`feature a Wheel for scrolling; US. Pat. No. 5,530,455 to
`Gillick et al discloses a mouse With a scroll Wheel mechani
`cally coupled to another optical rotary encoder. Such
`mechano-optical mice are Widely used and Well understood,
`but they do suffer several draWbacks. First, as moving parts
`they are susceptible to mechanical failure and may need
`periodic cleaning. Second, they are eXposed to dirt,
`moisture, and other contaminants and environmental effects.
`Third, as loW-cost mechanical devices they may be less
`sensitive to ?ne movements than fully electronic devices.
`Fourth, electromechanical sensors may be more expensive
`than purely electronic sensors. And ?fth, optical sensors
`draW a signi?cant amount of poWer due to their use of light
`emitting diodes.
`Another Well-knoWn type of mouse measures motion by
`direct optical sensing of the surface beneath the mouse. US.
`Pat. No. 4,364,035 to Kirsch discloses an optical mouse that
`Worked With patterned surfaces, and US. Pat. No. 5,907,152
`to Dandliker et al discloses a more sophisticated eXample
`that Works With natural surfaces. US. Pat. No. 5,288,993 to
`Bidiville et al discloses a pointing device Which includes a
`rotating ball but measures the rotation of the ball by purely
`optical means. Optical mice eliminate the difficulties asso
`ciated With moving parts in the motion sensor, but even they
`must typically use mechanical mouse buttons and a
`mechanical scroll Wheel.
`Many alternatives to scroll Wheels have been tried. US.
`Pat. No. 5,883,619 to Ho et al discloses a mouse With a
`four-Way scrolling button. US. Pat. No. 5,313,229 to Gil
`ligan et al discloses a mouse With a thumb-activated scroll
`ing knob. US. Pat. No. 5,122,785 to Cooper discloses a
`mouse that is squeeZed to initiate scrolling. The ScrollPoint
`Mouse from International Business Machines includes an
`isometric joystick for scrolling, and the ScrollPad Mouse
`from Fujitsu includes a resistive touch sensor for scrolling.
`The proliferation of such devices shoWs both that there is a
`need for a good scrolling device for use With mice, and that
`none of the technologies tried so far are completely satis
`factory.
`Capacitive touch pads are also Well knoWn in the art; US.
`Pat. No. 5,880,411 discloses a touch pad sensor and asso
`ciated features. Touch pads can simulate the motion detector
`and buttons of a mouse by measuring ?nger motion and
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`55
`
`60
`
`65
`
`2
`detecting ?nger tapping gestures. Touch pads can also be
`used for scrolling, as disclosed in US. Pat. No. 5,943,052.
`Capacitive touch pads are solid state electronic devices that
`avoid many of the pitfalls of mechanical sensors. HoWever,
`many users prefer mice over touch pads for reasons of
`ergonomics or familiarity.
`Capacitive touch sensors for use as sWitches are Well
`knoWn in the art. For example, US. Pat. No. 4,367,385 to
`Frame discloses a membrane pressure sWitch that uses
`capacitance to detect activation. US. Pat. No. 5,867,111 to
`CaldWell et al discloses a capacitive sWitch that directly
`detects the capacitance of the user. The circuits of the ’411
`patent already cited could also be used to implement a
`capacitive sWitch. Applications of capacitive sWitches to
`mice are relatively rare, but in the paper “Touch-Sensing
`Input Devices” (ACM CHI ’99, pp. 223—230), Hinckley and
`Sinclair disclose an experimental mouse With capacitive
`touch sensors to detect the presence of the user’s hand on or
`near various mouse controls.
`US. Pat. No. 5,805,144 to Scholder et al discloses a
`mouse With a touch pad sensor embedded in it. HoWever,
`Scholder only considers resistive and thermal touch sensors,
`Which are less sensitive and less able to be mounted Within
`the plastic enclosure of the mouse than capacitive sensors.
`Scholder suggests using the touch sensor in lieu of mouse
`buttons, but does not consider the use of the touch sensor for
`scrolling.
`The purpose of the present invention is to create a device
`With the familiar form and function of a mouse, Wherein
`some or all of the mechanical functions of the mouse have
`been replaced by capacitive sensors.
`
`SUMMARY OF THE INVENTION
`The present invention is directed toWard a pointing device
`similar to a conventional mouse, but some or all of Whose
`elements are made from capacitive sensors. Such elements
`may include a rotary motion detector Which includes a
`rotating member and a plurality of ?Xed capacitive detecting
`members; a rolling ball With patterned conductive surface
`and a plurality of ?Xed capacitive detecting members;
`capacitive touch sensors or capacitive sWitches to serve as
`mouse buttons; and a scrolling Wheel, knob, or touch surface
`built from capacitive sensors. The pointing device further
`includes a capacitance measuring circuit and processor to
`measure variations of capacitance on the various capacitive
`elements and to determine the movement of and other
`activations of the mouse.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1A is a side plan vieW of a mouse typical of the prior
`art.
`FIG. 1B is a top plan vieW of a mouse typical of the prior
`art.
`FIG. 2A is a schematic vieW of a typical prior art rotary
`encoder.
`FIG. 2B is a partial side plan vieW of a rotary disk and
`light detector employed by mice of the prior art.
`FIG. 2C is a digital quadrature Waveform generated by the
`rotary disk of FIG. 2B.
`FIG. 2D shoWs an alternative Waveform to that of FIG.
`2C.
`FIG. 3A is a schematic vieW of a rotary encoder that
`operates on capacitive principles rather than that Which
`operates on optical principles as depicted in FIG. 2A.
`FIG. 3B is a partial side plan vieW of a notched disk and
`related capacitance detector.
`
`Microsoft Ex. 1019
`Microsoft v. Philips - IPR2018-00025
`Page 13 of 21
`
`

`

`US 6,587,093 B1
`
`3
`FIG. 3C is a depiction of a Waveform as generated by the
`notched disk and capacitance detector of FIG. 3B.
`FIGS. 3D and 3E are depictions of Waveforms as gener
`ated by the notched disk and capacitance detector of FIG. 3B
`Where the capacitance plates rotate in an opposite direction
`to that of FIG. 3C.
`FIG. 4 is a partial schematic side vieW of a capacitive
`rotary encoder for use herein.
`FIG. 5 is a partial side plan vieW of a rotary encoder as an
`enhancement of the encoder depicted in FIG. 3A.
`FIG. 6 is a partial schematic side vieW of a mechanism for
`capacitively sensing mouse motion.
`FIG. 7 is a partial schematic side vieW of a capacitance
`detector and capacitance measurement circuit for use herein.
`FIGS. 8A and 8B are side vieWs of typical capacitive
`sWitches housed Within a mouse enclosure.
`FIG. 9 is a partial schematic side vieW of a scrolling
`Wheel, capacitive rotary encoder and processor for use
`herein.
`FIG. 10 is a partial schematic vieW of a further version of
`a capacitive scrolling control for use in the present inven
`tion.
`FIGS. 11A through 11D are side and top plan vieWs,
`respectively, of a mouse enclosure shoWing plates for
`capacitive sensing.
`FIGS. 12A through 12E are side vieWs of sensors
`mounted for use herein.
`FIGS. 13A through 13D are schematic vieWs of alterna
`tive patterns for sensors for use herein.
`FIG. 14 is a top plan vieW of a mouse enclosure and
`scrolling area for use in creating the present capacitive
`mouse.
`FIG. 15 are graphical depictions shoWing total summed
`capacitance signal over time in employing the capacitive
`mouse of the present invention.
`FIGS. 16A through 16C are graphical depictions of the
`coasting feature of the present invention.
`FIG. 17 is a side vieW of a mouse enclosure housing the
`capacitive features of the present invention.
`FIG. 18 is a schematic vieW of a scrolling module for use
`as a component of the present capacitive mouse.
`
`DESCRIPTION OF PREFERRED EMBODIMENT
`
`For reference, FIG. 1A shoWs the elements of a conven
`tional prior art mouse 100 in side vieW. Enclosure 102,
`typically of hard plastic, forms the body of the mouse. Ball
`104 protrudes from the bottom of enclosure 102 through a
`small hole. Motion of the mouse over a ?at surface causes
`ball 104 to rotate; this rotation is measured by rotary
`encoders 106. Typically tWo rotary encoders are used to
`measure motion of the mouse in tWo orthogonal aXes.
`Buttons 108 form part of the top surface of enclosure 102.
`Finger pressure on buttons 108 is detected by sWitches 110
`mounted beloW the buttons. Scroll Wheel 112 is mounted
`betWeen buttons 108; its rotation is measured by rotary
`encoder 114. Inputs from rotary encoders 106 and 114 and
`sWitches 110 are combined by processor 116 and transmitted
`to a host computer via cable 118.
`FIG. 1B shoWs the same mouse 100 in top vieW, featuring
`enclosure 102, ball 104, buttons 108, scroll Wheel 112, and
`cable 118.
`FIG. 2A shoWs a typical prior art rotary encoder 200.
`Rotation of ball 202 causes shaft 204 to spin, thus rotating
`
`15
`
`25
`
`35
`
`45
`
`55
`
`65
`
`4
`notched disc 206. Light emitter 208 passes light beam 214
`through the notches of disc 206 to light detector 210. As disc
`214 spins, the pattern of signals from detector 210 alloWs
`processor 212 to deduce the direction and speed of rotation.
`Note that shaft 204 is eXcited only by rotation of ball 202
`about an aXis parallel to shaft 204. By mounting a second
`rotary decoder (not shoWn) perpendicular to rotary decoder
`200, rotation of ball 202 about tWo aXes, and hence motion
`of the mouse in a tWo-dimensional plane, can be detected.
`FIG. 2B shoWs a detail vieW of notched disc 206 and light
`detector 210. Detector 210 actually contains tWo light sen
`sitive elements 220 and 222 spaced closely together relative
`to the spacing of notches 224. As disc 206 rotates in the
`direction indicated by arroW 226, light sensitive elements
`220 and 222 are ?rst both eXposed to light through notch
`224, then element 220 is eclipsed by the body of disc 206,
`then element 222 is also eclipsed, then element 220 is
`eXposed to light through adjacent notch 228, then element
`222 is also eXposed to light through notch 228. Sensors 220
`and 222 thus generate the digital quadrature Waveform
`shoWn in FIG. 2C over time. If disc 206 rotates in the
`direction opposite arroW 226, the sensors are eclipsed in the
`opposite order and they generate the digital Waveform
`shoWn in FIG. 2D. By digitally reading the outputs of light
`sensors 220 and 222 and decoding the quadrature signals
`therein, the processor can determine the direction and
`amount of motion of disc 206.
`In an alternate embodiment, light sensitive elements 220
`and 222 can be separated and placed at analogous positions
`Within tWo distinct notch positions of disc 206. This embodi
`ment is preferable if the light sensors 220 and 222 are too
`large to be placed closely together; the disadvantage is that
`it is more difficult to align sensors 220 and 222 precisely
`relative to one another.
`FIG. 3A shoWs a rotary encoder 300 that operates on
`capacitive instead of optical principles. Ball 302 spins shaft
`304 and notched disc 306. Shaft 304 and disc 306 are made
`of a conductive material such as metal, and the assembly
`consisting of shaft 304 and disc 306 is electrically grounded
`by grounding element 308. Capacitance detector 310 mea
`sures the capacitive effects of grounded disc 306. Various
`methods for grounding a spinning object, such as metal
`brushings, are knoWn in the art. Alternatively, only disc 306
`can be made conductive, With ground 308 applied directly to
`disc 306. In yet another alternative embodiment, disc 306 is
`capacitively coupled to a nearby grounded object. In yet
`another embodiment, a transcapacitance measurement may
`be done betWeen the body of disc 306 and detector 310,
`possibly by driving a time-varying signal into disc 306 and
`measuring the amplitude of coupling of that signal onto
`detector 310. In any case, capacitance detector 310 measures
`the position of disc 306 by its capacitive effects, and the
`resulting signals are read by processor 312.
`FIG. 3B shoWs a detail vieW of notched disc 306 and
`capacitance detector 310. As in the case of the optical
`detector of FIG. 2B, capacitance detector 310 is formed of
`tWo conductive plates 320 and 322 placed near but not
`touching the plane of disc 306. When notch 324 of disc 306
`is situated adjacent to plates 320 and 322, those plates each
`have a loW capacitance to ground. As the body of disc 306
`moves to be adjacent to plate 320 and then to plate 322, the
`capacitance to ground of these plates rises to a higher level.
`Because capacitance is linearly related to the area of overlap
`of conductive plates, this rise of capacitance of plate 320 is
`linear. As disc 306 completely covers plate 320 and begins
`to cover plate 322, the capacitance of plate 320 stays
`relatively constant While the capacitance of plate 322 lin
`
`Microsoft Ex. 1019
`Microsoft v. Philips - IPR2018-00025
`Page 14 of 21
`
`

`

`US 6,587,093 B1
`
`5
`early rises. As disc 306 continues to rotate in the direction
`of arroW 326, the capacitance of plate 320 and then plate 322
`falls linearly, as depicted in the Waveforms of FIG. 3C. If
`disc 306 rotates in a direction opposite arroW 326, the
`capacitances of plates 320 and 322 instead generate the
`Waveform of FIG. 3D.
`Those experienced in the art Will recognize that plates 320
`and 322 may be actual metal plates, or they may equiva
`lently be conductive regions formed in a variety of Ways,
`including but not limited to conductive ink painted or
`screened on a surface or substrate, conductive material such
`as metal or indium tin oxide plated or otherWise disposed on
`a surface or substrate, or any other conductive object With at
`least one substantially ?at portion placed in close proximity
`to disc 306. Similarly, the conductive notched disc 306 may
`be an actual notched metal disc, or it may be a notched
`conductive pattern formed on a disc-shaped substrate. The
`dielectric component of the capacitance betWeen plates 320
`and 322 and disc 306 may be an empty gap, a coating,
`surface, substrate, or other intermediary object, or some
`combination thereof Whose thickness and dielectric constant
`yield a conveniently measurable capacitance.
`Those experienced in the art Will further recogniZe that
`rotary capacitive sensors are not limited to the disc con?gu
`ration. Any arrangement in Which an irregular conductive
`object rotates near a conductive sensor Will Work equally
`Well. In one alternate embodiment, disc 306 is extruded to
`form a rotating drum With a notched or patterned conductive
`surface, and plates 320 and 322 are oriented along the long
`dimension of the drum. The drum embodiment is bulky and
`mechanically more complex, but alloWs a larger area of
`capacitive overlap and hence a stronger capacitance signal.
`In another alternate embodiment, the notched disc could be
`simpli?ed to a single “notch,” resulting in a semicircular
`conductive cam facing quarter-circle plates 320 and 322.
`One Way to process the capacitance signals from plates
`320 and 322 is to compare them against ?xed capacitance
`thresholds. Referring to FIGS. 3D and 3E, comparing
`capacitance 340 against threshold 344 yields digital Wave
`form 348; similarly, comparing capacitance 342 against
`threshold 346 yields digital Waveform 350. Note that Wave
`forms 348 and 350 of FIG. 3E are identical in nature to the
`digital Waveforms of FIG. 2D. Hence, if threshold compari
`son is used in this manner to generate digital Waveforms,
`these digital Waveforms can be processed by a processor 312
`identical to processor 212 of the conventional optical rotary
`encoder of FIG. 2B.
`Capacitance detector 310 can use any of a number of
`methods for measuring capacitance as are knoWn in the art.
`US. Pat. No. 5,880,411 discloses one such capacitance
`measuring circuit.
`As in the case of the optical encoder of FIG. 2A, note that
`plates 320 and 322 may be placed adjacent to different
`notches as long as their positioning Within their respective
`notches is maintained. HoWever, since plates 320 and 322 do
`not require housings or packages outside the plates
`themselves, it is convenient to place them side by side
`mounted on a common substrate in order to ensure that they
`Will remain aligned to each other.
`One skilled in the art Will observe that by examining the
`original analog capacitance Waveforms of FIGS. 3C and 3D,
`it is possible to locate disc 306 to a much ?ner resolution
`than the notch spacing. This is because at any given point in
`time, one of the capacitance signals is varying linearly With
`disc rotation While the other is constant. By tracking these
`linear variations, processor 312 can track disc rotation at a
`
`10
`
`15
`
`25
`
`35
`
`45
`
`55
`
`65
`
`6
`resolution limited only by the resolution and linearity of the
`capacitance measurements. In the preferred embodiment,
`the circuits disclosed in US. Pat. No. 5,880,411 are used to
`perform these precise capacitance measurements.
`Because disc rotation can be measured to much higher
`resolution than the notch spacing, it is possible to use much
`larger notches on disc 306, and correspondingly larger plates
`320 and 322, than are feasible for the analogous notches and
`sensors of the optical encoder of FIG. 2A. Larger notches
`and plates alloW mechanical tolerances of the assembly to be
`relaxed, yielding potentially loWer costs. Even With larger
`notches and plates, a capacitive rotary encoder can produce
`higher-resolution data than an optical rotary encoder if a
`suf?ciently high-resolution capacitance detector is used.
`Larger plates 320 and 322 also result in a larger capacitance
`signal Which is easier for detector 310 to measure.
`The plates 320 and 322 and grounding mechanism 308,
`being simple formed metal pieces or plated conductive
`patterns, may also be less costly than the semiconductor
`light emitters and sensors of FIG. 2A.
`Another advantage of the capacitive rotary encoder is that
`it is not affected by optically opaque foreign matter, such as
`dirt, Which may be picked up and introduced into the
`assembly by ball 306. The looser mechanical tolerances
`alloWed by the capacitive rotary encoder may also make it
`more resistant to jamming by foreign matter.
`FIG. 4 shoWs a side vieW of the capacitive rotary encoder,
`With disc 400 and plates 402 and 404 separated by a gap 406.
`Gap 406 is draWn large for illustrative purposes, but in the
`preferred embodiment gap 406 is kept as small as possible
`to maximiZe the capacitance betWeen disc 400 and plates
`402 and 404. If gap 406 is small, and the tolerances of the
`encoder assembly are loose as previously disclosed, then
`movement of disc 400 along the axis of shaft 408 Will have
`a proportionately large effect on the Width of gap 406. This
`variation can impact the accuracy of the capacitance mea
`surements of plates 402 and 404. FIG. 5 shoWs an enhance
`ment to the arrangement of FIG. 3A that solves this problem.
`In FIG. 5, disc 500 is adjacent to three plates 502, 504, and
`506. Plates 502 and 504 are identical to plates 320 and 322
`of FIG. 3A. Plate 506 is the siZe of plates 502 and 504
`combined, and is located near plates 502 and 504; in FIG. 5,
`plate 506 occupies the next notch space after plates 502 and
`504. In an alternative embodiment, matching could be
`improved by splitting plate 506 into tWo half-plates each
`exactly the siZe of plates 502 and 504. In the system of FIG.
`5, the processor computes the sum of the capacitance
`measurements from plates 502, 504, and 506. Note that the
`total overlap area betWeen disc 500 and plates 502, 504, and
`506 is constant regardless of the rotary position of disc 500.
`Hence, the summed capacitance of plates 502, 504, and 506
`should be constant. Variation in this sum indicates that disc
`500 has shifted relative to plates 502, 504, and 506, for
`example, by moving along the axis as shoWn in FIG. 4. The
`processor divides each plate capacitance measurement by
`the summed capacitance in order to normaliZe the capaci
`tance measurements. These normaliZed measurements are
`invariant of the Width of gap 406 of FIG. 4, and are suitable
`for use in the position computations previously discussed.
`FIG. 6 shoWs an alternative mechanism for capacitively
`sensing mouse motion. This mechanism employs a rolling
`ball 602 protruding from a hole in enclosure 600 similar to
`that of a conventional mouse. The surface of ball 602 is
`patterned With regions 604 of higher and loWer conductivity.
`This patterning can be accomplished by forming the ball of
`material such as rubber of varying conductivity, or by
`
`Microsoft Ex. 1019
`Microsoft v. Philips - IPR2018-00025
`Page 15 of 21
`
`

`

`US 6,587,093 B1
`
`7
`treating the surface of the ball With conductive substances
`such as paint or metal. The conductive surface of the ball
`may be protected if necessary by a dielectric outer layer 606.
`Capacitance detectors 608 are placed in several locations
`proximate to ball 602. As the ball rolls, the conductive
`regions 604 Will move from one capacitance detector to
`another; processor 610 correlates these signals to measure
`the movement of ball 602. Because the capacitance mea
`surements vary linearly as conductive region 604 moves
`from one detector 608 to another, processor 610 can inter
`polate in order to measure movement of the ball to very high
`resolution.
`The system of FIG. 6 requires several sensors 608 in order
`to ensure that at least one conductive region 604 is detect
`able at all times. Conductive regions 604 should be as large
`as possible in order to maXimiZe the capacitive signal,
`subject to the constraint that different regions 604 should be
`separated by enough distance to alloW individual regions
`604 and the spaces betWeen them to be resolved by detectors
`608. Hence, the spaces betWeen regions 604 should be at
`least comparable to the siZe of detectors 608, and the
`conductive regions 604 should be at least a signi?cant
`fraction of the siZe of detectors 608.
`FIG. 6 depicts a linear roW of sensors 608 curved around
`the surface of ball 602. Such an arrangement can detect
`rolling of the ball in one dimension; the eXample of FIG. 6
`Would detect the rolling resulting from motion of the mouse
`along aXis 612. In the preferred embodiment, other sensors
`(not shoWn) are arranged in a roW perpendicular to the roW
`of sensors 608 in order to measure motion of the mouse in
`tWo dimensions.
`In one embodiment, the conductive regions in the ball are
`grounded to facilitate capacitance measurements by simple
`conductive plates. HoWever, grounding the conductive
`regions of the ball may be impractical, so in the preferred
`embodiment, capacitance detectors 608 measure tran
`scapacitance.
`FIG. 7 shoWs one simple Way to measure transcapaci
`tance. The capacitance detector 700 consists of tWo plates
`702 and 704. Plate 702 is connected to ground, and plate 704
`is connected to a capacitance measurement circuit 706.
`Proximity to an electrically ?oating conductor 708 Within
`ball 710 creates a capacitive coupling 712 from plate 702 to
`conductor 708, and a capacitive coupling 714 from conduc
`tor 708 to plate 704, hence effectively coupling plate 702 to
`plate 704 through tWo series capacitances. Those experi
`enced in the art Will recogniZe that many other con?gura
`tions of plates 702 and 704 are possible, such as interdigi
`tated lines or concentric circles and toroidal shapes. In still
`another embodiment of capacitance detector 700, plate 702
`could be driven With a time-varying signal Which is capaci
`tively coupled onto plate 704 and detected by circuit 706.
`The motion sensor of FIG. 6 requires even feWer moving
`parts than that of FIG. 3, and thus can lead to an even
`cheaper and more physically robust mouse. HoWever, the
`system of FIG. 6 has the disadvantage of requiring more
`complex processing in processor 610.
`Other methods for detecting mouse motion are k