THI T
`
`ALUTULUMTIH
`
`US009746967B2
`
`( 12 ) United States Patent
`Krah et al .
`
`( 10 ) Patent No . :
`( 45 ) Date of Patent :
`
`US 9 , 746 , 967 B2
`Aug . 29 , 2017
`
`( 54 ) CONCURRENT TOUCH AND NEGATIVE
`PIXEL SCAN
`( 75 ) Inventors : Christoph Horst Krah , Los Altos , CA
`( US ) ; Marduke Yousefpor , San Jose ,
`CA ( US )
`( 73 ) Assignee : Apple Inc . , Cupertino , CA ( US )
`Subject to any disclaimer , the term of this
`( * ) Notice :
`patent is extended or adjusted under 35
`U . S . C . 154 ( b ) by 1515 days .
`( 21 ) Appl . No . : 13 / 234 , 095
`Sep . 15 , 2011
`( 22 ) Filed :
`Prior Publication Data
`( 65 )
`US 2013 / 0069905 A1 Mar . 21 , 2013
`( 51 ) Int . CI .
`( 2006 . 01 )
`GOOF 3 / 044
`( 2006 . 01 )
`G06F 3 / 041
`U . S . CI .
`CPC . . . . . . . . . . . G06F 3 / 044 ( 2013 . 01 ) ; G06F 3 / 0418
`( 2013 . 01 )
`( 58 ) Field of Classification Search
`??? . . . . . . . . . . . . . . . . . . GO6F 3 / 0418 ; G06F 3 / 044 ; G06F
`2203 / 04104
`USPC . . . . . . . . . 345 / 173 - 179 ; 178 / 18 . 01 – 18 . 11 , 19 . 01
`See application file for complete search history .
`References Cited
`U . S . PATENT DOCUMENTS
`5 , 483 , 261 A
`1 / 1996 Yasutake
`5 , 488 , 204 A
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`11 / 1998 Shieh
`3 / 1999 Gillespie et al .
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`10 / 2001 Beaton et al .
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`( 52 )
`
`( 56 )
`
`csy Marduke Yousef
`
`6 , 323 , 846 B1 11 / 2001 Westerman et al .
`6 , 690 , 387 B2
`2 / 2004 Zimmerman et al .
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`3 / 2006 Morohoshi
`7 , 184 , 064 B2
`2 / 2007 Zimmerman et al .
`7 , 663 , 607 B2
`2 / 2010 Hotelling et al .
`8 , 479 , 122 B2
`7 / 2013 Hotelling et al .
`2006 / 0026521 A1 2 / 2006 Hotelling et al .
`2006 / 0197753 AL
`9 / 2006 Hotelling
`2009 / 0009483 A1 *
`1 / 2009 Hotelling et al .
`2009 / 0250268 A1 *
`10 / 2009 Staton et al .
`. . . . .
`2010 / 0060590 A1
`3 / 2010 Wilson et al .
`( Continued )
`FOREIGN PATENT DOCUMENTS
`2000 - 163031 A
`6 / 2000
`2002 - 342033 A
`11 / 2002
`
`JP
`
`345 / 173
`. . . . . . . . 178 / 18 . 06
`
`OTHER PUBLICATIONS
`Lee , S . K . et al . ( Apr . 1985 ) . “ A Multi - Touch Three Dimensional
`Touch - Sensitive Tablet , ” Proceedings of CHI : ACM Conference on
`Human Factors in Computing Systems , pp . 21 - 25 .
`( Continued )
`Primary Examiner — Kent Chang
`Assistant Examiner — Scott Au
`( 74 ) Attorney , Agent , or Firm — Morrison & Foerster ,
`LLP
`( 57 )
`ABSTRACT
`A concurrent touch and negative pixel scan performed at a
`touch panel is disclosed . The concurrent scan can include
`sensing an object proximate to the touch panel and sensing
`a negative pixel effect , based the object ' s grounding condi
`tion , at the touch panel , at the same time . As a result , sense
`signals indicative of the proximity of the object and coupling
`signals indicative of the negative pixel effect ' s magnitude
`can be captured concurrently . Because the negative pixel
`effect can cause errors or distortions in the sense signals , the
`coupling signals can be used to compensate the sense signals
`for the negative pixel effect .
`12 Claims , 10 Drawing Sheets
`
`VSTM
`
`116
`
`- D0
`
`| |
`
`P
`
`=
`
`VSTIM —
`
`- 24
`
`PIXEL
`- 126 - a 1
`
`* from 126 - 6
`126 135
`
`126 - d 1
`
`TOUCH PANEL
`124
`
`SENSE LINE
`102
`
`50
`
`51
`
`52
`
`101
`DRIVE LINE
`
`53 * * *
`
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`

`US 9 , 746 , 967 B2
`Page 2
`
`( 56 )
`
`References Cited
`U . S . PATENT DOCUMENTS
`2010 / 0060593 AL
`3 / 2010 Krah
`345 / 174
`2010 / 0060608 A1 *
`3 / 2010 Yousefpor . . . . . . . . . . . . . . . . .
`2010 / 0073301 A1 *
`3 / 2010 Yousefpor et al . . . . . . . . . . . 345 / 173
`2010 / 0079401 A1 4 / 2010 Staton
`2010 / 0079402 A1
`4 / 2010 Grunthaner et al .
`2010 / 0097343 A1 *
`4 / 2010 Fang .
`. . . . . . . . . . .
`2011 / 0006832 AL
`1 / 2011 Land et al .
`2011 / 0061949 Al
`3 / 2011 Krah et al .
`345 / 174
`2011 / 0102361 A1 *
`5 / 2011 Philipp . . . . . . . . . . . . . . . . .
`345 / 173
`2011 / 0298734 A1 * 12 / 2011 Ho et al . . . . . . . . . . . . . . . . . .
`2012 / 0105353 A1 *
`5 / 2012 Brosnan . . . . . . . . . . . . . . . . . . G06F 3 / 044
`345 / 174
`
`345 / 174
`
`OTHER PUBLICATIONS
`Rubine , D . H . ( Dec . 1991 ) . “ The Automatic Recognition of Ges
`tures , ” CMU - CS - 91 - 202 , Submitted in Partial Fulfillment of the
`Requirements for the Degree of Doctor of Philosophy in Computer
`Science at Carnegie Mellon University , 285 pages .
`Rubine , D . H . ( May 1992 ) . “ Combining Gestures and Direct
`Manipulation , ” CHI ’ 92 , pp . 659 - 660 .
`Westerman , W . ( Spring 1999 ) . “ Hand Tracking , Finger Identifica
`tion , and Chordic Manipulation on a Multi - Touch Surface , ” A
`Dissertation Submitted to the Faculty of the University of Delaware
`in Partial Fulfillment of the Requirements for the Degree of Doctor
`of Philosophy in Electrical Engineering , 364 pages .
`* cited by examiner
`
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`U . S . Patent
`
`Aug . 29 , 2017
`
`Sheet 1 of 10
`
`US 9 , 746 , 967 B2
`
`TOUCH PANEL
`124
`
`PIXEL
`- 126 - a tv o
`
`126 -
`
`116
`
`8
`
`8
`
`VSTIM —
`
`D2
`
`1260 I
`126 - d
`.
`
`A
`
`126 - C
`
`8
`
`SO
`
`S1
`
`S2
`
`FIG . 1
`
`SENSE LINE
`102
`
`101
`DRIVE LINE
`S3
`
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`U . S . Patent
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`Aug . 29 , 2017
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`Sheet 2 of 10
`
`US 9 , 746 , 967 B2
`
`INTEGRATER - 242 - C
`220
`MIXER 242 - b
`DIGITAL DEMODULATOR 248 242
`2412 e
`ADC
`
`219 - 2
`
`
`
`VECTOR OPERATOR 244
`
`244 - b INTEGRATER
`po 5 - Cos
`244 - a MIXER
`
`- Cod
`
`DECODE MATRIX M '
`
`244
`
`VECTOR OPERATOR
`CROSS - COUPLING MATRIXN
`242 DIGITAL DEMODULATOR
`
`ADC H DELAY - 0 - 5 - 0 - -
`
`ADC
`
`FIG . 2
`
`AAF
`246
`
`234
`
`AMPLIFIER
`SENSE
`
`
`
`SENSE LINE
`
`- 202
`
`M
`
`| Cdd +
`
`
`TOUCH PANEL
`TOUCH PANEL 224
`
`
`DRIVE LINE 201
`
`DRIVE LINE
`201
`VSTIM + Vdd 1
`MUX
`
`
`
`TOUCH SENSITIVE DEVICE 200
`
`VSTIMN . Rfb - Ex
`TOUCH BUFFER 220
`
`
`
`222 - a
`
`Vadovado
`
`SEL
`
`222 - 6
`
`MUX
`
`vstu * You
`VSTIM + Ved
`SEL
`
`|
`
`Vodi
`
`Vodo
`
`hopen
`
`Riflo - tx
`
`len
`
`VSTi
`VSTIM
`
`
`
`TOUCH BUFFER 220
`
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`U . S . Patent
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`Aug . 29 , 2017
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`Sheet 3 of 10
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`US 9 , 746 , 967 B2
`
`234 SENSE AMPLIFIER
`
`S8 + 421
`- Vref
`MUX 326
`SENSE LINE 302
`
`
`
`301 DRIVE LINE
`
`LSEL
`
`FIG . 3A
`
`concesto
`
`LSEL
`
`301 Idd - sig
`
`DRIVE LINE
`
`
`
`TOUCH PANEL 224
`
`SENSE LINE
`302
`MUX
`322
`
`Rfb - tx
`
`
`
`TOUCH SENSITIVE DEVICE 300
`
`
`
`TOUCH BUFFER
`
`220
`
`N
`
`VSTIM
`
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`U . S . Patent
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`Aug . 29 , 2017
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`Sheet 4 of 10
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`US 9 , 746 , 967 B2
`
`DRIVE LINE
`
`301
`
`DO - 8 .
`
`D1 -
`
`301
`DRIVE LINE
`
`FINGER
`
`Ctók / FINGER
`Vlcio
`Cond S
`
`CITOT - CIDO - CID?
`? CITOT - Cipo - Cfp1
`
`FIG . 3B
`
`50
`
`51
`
`302
`SENSE LINE
`
`302
`SENSE LINE
`
`y como
`
`ICtor - Crico - City
`+ cftot - Ciso - Cis1
`
`FINGER
`
`FIG . 3C
`
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`U . S . Patent
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`Aug . 29 , 2017
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`Sheet 5 of 10
`
`US 9 , 746 , 967 B2
`
`244
`
`242
`
`- 454 452 - d
`A DC * @
`
`248
`
`VECTOR OPERATOR
`VECTOR OPERATOR
`VECTOR
`DIGITAL DEMOD .
`bet
`DIGITAL DEMOD . DIGITAL
`ADC ADC NO
`SCALER
`RR154
`SCALE
`vir SCALE FACTOR
`DI
`Vref
`TOUCH
`TOUCH PANEL
`224 224
`
`AAF 246
`
`
`
`SENSE AMPLIFIER 234
`
`Vdd + Vcom + V
`
`238
`
`ADC
`
`244
`
`242
`
`452 - a
`
`244
`
`242
`
`VECTOR OPERATOR
`DIGITAL DEMOD .
`
`452 - C
`
`SCALER 456
`
`458
`
`Vdc
`
`DELAY
`DELAY
`NCO
`
`452 - b 452 - 6
`
`SCALE FACTOR
`
`Vad + Vcom + Vd
`
`FIG . 4
`
`238
`
`ADC
`
`AAF 236
`236
`VSTIMN VSTIM + Ved + Vcom
`ddo
`7 ddo AAF
`
`
`
`E
`&
`
`MUX
`
`Vodit222
`
`Rfb - tx
`
`
`
`TOUCH BUFFER 220
`
`VSTIM + Vad + Vcom AAF AF 236
`
`ddo
`
`N
`
`
`
`TOUCH BUFFER 220
`VSTIM
`
`
`
`TOUCH SENSITIVE DEVICE
`
`400
`
`H
`Vado
`Vodi
`Vadi
`
`Rfb - tx
`
`222 MUX
`
`Cod
`
`LCD
`
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`U . S . Patent
`
`Aug . 29 , 2017
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`Sheet 6 of 10
`
`US 9 , 746 , 967 B2
`
`PERFORM CONCURRENT
`TOUCH & NEGATIVE PIXEL SCAN
`
`- 505
`
`CAPTURE CROSS - COUPLING
`SIGNALS & SENSE SIGNALS
`
`- 510
`
`PROCESS SENSE SIGNALS &
`CROSS - COUPLING SIGNALS
`
`- 520
`
`USE CROSS - COUPLING SIGNALS
`TO COMPENSATE SENSE SIGNALS
`FOR NEGATIVE PIXEL EFFECT
`
`1525
`
`FIG . 5
`
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`atent
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`Aug . 29 , 2017
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`Sheet 7 of 10
`
`US 9 , 746 , 967 B2
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`PERFORM 1ST CONCURRENT
`TOUCH & NEGATIVE PIXEL SCAN
`
`1605
`
`CAPTURE 1ST CROSS - COUPLING
`SIGNALS & SENSE SIGNALS
`
`610
`
`SWITCH TO DIFFERENT
`DRIVE - SENSE CONFIGURATION
`
`- 620
`
`PERFORM 2ND CONCURRENT
`TOUCH & NEGATIVE PIXEL SCAN
`
`1630
`
`CAPTURE 2ND CROSS - COUPLING
`SIGNALS & SENSE SIGNALS
`
`- 635
`
`PROCESS 1ST & 2ND
`SETS OF SIGNALS
`
`645
`
`USE 1ST & 2ND CROSS - COUPLING
`SIGNALS TO COMPENSATE SENSE
`SIGNALS FOR NEGATIVE PIXEL EFFECT
`
`FIG . 6
`
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`U . S . Patent
`
`Aug . 29 , 2017
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`Sheet 8 of 10
`
`US 9 , 746 , 967 B2
`
`PERFORM CONCURRENT
`TOUCH & NEGATIVE PIXEL SCAN
`
`705
`
`CAPTURE CROSS - COUPLING SIGNALS , \
`SENSE SIGNALS , & NOISE SIGNALS
`
`710
`
`REJECT NOISE SIGNALS
`
`RELECT MOISE SIGNALS
`
`PROCESS SENSE SIGNALS &
`CROSS - COUPLING SIGNALS
`
`725
`
`USE CROSS - COUPLING SIGNALS
`TO COMPENSATE SENSE SIGNALS
`FOR NEGATIVE PIXEL EFFECT
`
`1730
`
`FIG . 7
`
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`U . S . Patent
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`Aug . 29 , 2017
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`Sheet 9 of 10
`
`US 9 , 746 , 967 B2
`
`S T
`
`E
`
`mund
`800
`
`SENSOR
`
`1
`
`1
`
`830
`
`DISPLAY
`DEVICE
`
`PROCESSOR
`
`???
`
`wwwton
`
`PROGRAM
`STORAGE
`
`828 618
`SECTION ? RAM
`
`??
`
`PROCESSOR ( - 802
`SUBSYSTEM
`1
`
`DEMOD .
`
`SUKAN
`
`810
`
`5
`
`CHARGE
`PUMP
`
`814
`
`- 806
`TOUCH
`CONTROLLER
`
`STIMULATION
`SIGNALS
`
`Hartmann
`
`m
`
`haran
`
`RECEIVE
`SECTION
`
`PANEL SCAN
`LOGIC
`
`TRANSMIT
`SECTION
`
`wwwwwwwwwwwwwww
`
`wwwwwwwwwwwwwww
`
`CONTROL SIGNALS
`
`TOUCH SENSOR
`PANEL
`TOUCH SIGNALS
`824 C?iG
`LA www G VW
`
`026 PIXEL
`
`FIG . 8
`
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`U . S . Patent
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`Aug . 29 , 2017
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`Sheet 10 of 10
`
`US 9 , 746 , 967 B2
`
`B * *
`TELEPHONE
`900
`
`DISPLAY
`DEVICE
`936
`
`nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
`
`TOUCH
`SENSOR
`PANEL
`
`4
`
`FIG . 9
`
`MEDIA
`PLAYER
`1000
`
`PERSONAL
`COMPUTER
`1100
`
`www DISPLAY
`DEVICE
`TOUCH
`1036
`SENSOR PANEL
`
`are create
`
`ww
`
`1024
`
`w
`
`www
`
`W FIG . 10
`
`W
`
`W WWWWWYYYYYYYYYYYYYYYYYYYY
`Wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww
`wwwwwwwwwwwwwwwwwwwwwwwwwwwwwww
`1111100011
`
`gere
`w
`wwwwwww wiu
`
`sunkband kuingia
`
`ANNON
`
`KKKKKKKKKKKKKKK
`
`K KKALAU DISPLAY
`- 1136
`
`_ TRACKPAD
`
`TRACKPAD
`m 1124
`
`wwwwwwwwwwwwwwww
`Uw W
`WWWWWWWWWW
`+ + + + +
`+ + +
`+ + + + + + + + + + + +
`
`FIG . 11
`
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`US 9 , 746 , 967 B2
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`10 10
`
`50
`
`CONCURRENT TOUCH AND NEGATIVE
`PIXEL SCAN
`
`a scan period . In another example , multiple successive
`concurrent scans can be performed at the touch panel during
`a scan period . By performing the touch and negative pixel
`scan concurrently , rather than sequentially , the touch sensi
`FIELD
`5 tive device can advantageously save processing time and
`power consumption , while improving touch and hover sens
`This relates generally to touch panels and more particu
`ing , particularly for multiple simultaneous touch or hover
`larly to concurrent scans of touch panels .
`events .
`BACKGROUND
`BRIEF DESCRIPTION OF THE DRAWINGS
`Many types of input devices are presently available for
`FIG . 1 illustrates an exemplary touch panel that can have
`performing operations in a computing system , such as
`a concurrent touch and negative pixel scan according to
`buttons or keys , mice , trackballs , joysticks , touch sensor
`various embodiments .
`panels , touch screens and the like . Touch sensitive devices
`FIG . 2 illustrates an exemplary touch sensitive device that
`in particular are popular because of their ease and versatility 15
`can perform a concurrent touch and negative pixel scan at a
`of operation as well as their declining price . A touch
`touch panel according to various embodiments .
`sensitive device can include a touch sensor panel , which can
`FIGS . 3A , 3B , and 3C illustrate an exemplary touch
`be a clear panel with a touch sensitive surface . In some
`sensitive device that can switch touch panel configuration
`instances , a touch sensitive device can also include a display
`device such as a liquid crystal display ( LCD ) that can be 20 for a concurrent touch and negative pixel scan according to
`positioned partially or fully behind the panel or integrated
`various embodiments .
`with the panel so that the touch sensitive surface can cover
`FIG . 4 illustrates an exemplary touch sensitive device that
`at least a portion of the viewable area of the display device .
`can perform noise rejection during a concurrent touch and
`The touch sensitive device can allow a user to perform
`negative pixel scan at a touch panel according to various
`various functions by touching or hovering over the touch 25 embodiments .
`sensor panel using a finger , stylus or other object at a
`FIG . 5 illustrates an exemplary method for performing a
`location on the panel . In the instance of the display device ,
`concurrent touch and negative pixel scan at a touch panel
`the touching or hovering location can often be dictated by a
`according to various embodiments .
`user interface ( UI ) being displayed by the display device . In
`FIG . 6 illustrates another exemplary method for perform
`general , the touch sensitive device can recognize a touch or 30 ing a concurrent touch and negative pixel scan at a touch
`hover event and the position of the event on the touch sensor
`panel according to various embodiments .
`panel . The computing system can then interpret the event
`FIG . 7 illustrates an exemplary method for performing a
`and thereafter can perform one or more functions based
`concurrent touch and negative pixel scan at a touch panel
`and for rejecting noise in the panel according to various
`thereon .
`When the object touching or hovering over the touch 35 embodiments .
`FIG . 8 illustrates an exemplary computing system that can
`sensor panel is poorly grounded , data outputs indicative of
`the touch or hover event can be erroneous or otherwise
`perform a concurrent touch and negative pixel scan at the
`distorted . The possibility of such erroneous and distorted
`system ' s touch panel according to various embodiments .
`outputs can further increase when two or more simultaneous
`FIG . 9 illustrates an exemplary mobile telephone that can
`touch or hover events occur at the touch sensor panel .
`40 perform a concurrent touch and negative pixel scan at the
`Many touch sensitive devices are now recognizing simul -
`telephone ' s touch panel according to various embodiments .
`taneous touch or hover events , in addition to single touch or
`FIG . 10 illustrates an exemplary digital media player that
`hover events , as additional inputs to allow the user to
`can perform a concurrent touch and negative pixel scan at
`perform various functions associated with the simultaneous
`the player ' s touch panel according to various embodiments .
`events . As such , techniques to address poorly grounded 45
`FIG . 11 illustrates an exemplary portable computer that
`objects that cause the simultaneous events are becoming
`can perform a concurrent touch and negative pixel scan at
`quite important . The challenge is to develop a technique that
`the computer ' s touch panel according to various embodi
`appropriately addresses the erroneous of distorted outputs ,
`ments .
`yet does so in an efficient , effective manner .
`DETAILED DESCRIPTION
`SUMMARY
`In the following description of example embodiments ,
`reference is made to the accompanying drawings in which it
`This relates to a concurrent touch and negative pixel scan
`is shown by way of illustration specific embodiments that
`performed at a touch panel of a touch sensitive device . The
`concurrent scan can include sensing an object proximate to 55 can be practiced . It is to be understood that other embodi
`the touch panel and sensing a negative pixel effect , based the
`ments can be used and structural changes can be made
`object ' s grounding condition , on the touch panel , at the same
`without departing from the scope of the various embodi
`time . As a result , sense signals indicative of the proximity of
`ments .
`the object and coupling signals indicative of the negative
`This relates to a concurrent touch and negative pixel scan
`pixel effect ' s magnitude can be captured concurrently . The 60 performed at a touch panel of a touch sensitive device . The
`negative pixel effect can cause errors or distortions in the
`concurrent scan can include sensing an object proximate to
`sense signals , particularly when the sense signals indicate
`the touch panel , i . e . , the “ touch ” scan , and sensing a negative
`the proximate object touching or hovering over multiple
`pixel effect , based the object ' s grounding condition , at the
`touch panel locations . Accordingly , the coupling signals can
`touch panel , i . e . , the “ negative pixel ” scan , at the same time .
`be applied to the sense signals to compensate the sense 65 As a result , sense signals indicative of the proximity of the
`signals for the negative pixel effect . In one example , a single
`object and coupling signals indicative of the negative pixel
`concurrent scan can be performed at the touch panel during
`effect ' s magnitude can be captured concurrently . Because
`
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`US 9 , 746 , 967 B2
`
`Accordingly , the Csig signals captured during the scan can
`the negative pixel effect can cause errors or distortions in the
`be attenuated . In this example , drive lines DO , D2 can be
`sense signals , particularly when the sense signals indicate
`stimulated with stimulation signals 116 , forming a mutual
`the proximate object touching or hovering over multiple
`capacitance Csig between the stimulated drive line D0 and
`touch panel locations , the coupling signals can be applied to
`the sense signals to compensate the sense signals for the 5 the crossing sense lines SO - S3 and between the stimulation
`negative pixel effect .
`drive line D2 and the crossing sense lines SO - S3 . When
`In some embodiments , a single concurrent scan can be
`poorly grounded objects touch or hover over the panel 124
`performed at the touch panel during a scan period . In
`at stimulated pixels 126 - a and 126 - c formed by drive line DO
`alternate embodiments , multiple successive concurrent
`and sense line S1 and by drive line D2 and sense line S2 ,
`scans can be performed at the touch panel during a scan 10 respectively , the mutual capacitance Csig at pixels 126 - a and
`period , where each scan can be performed with a different
`126 - c can only be reduced by ( ACsig - Cneg ) , thereby attenu
`touch panel configuration .
`ating the sense signals transmitted on sense lines S1 , S2 and
`In some embodiments , noise can be introduced into the
`captured during the panel scan .
`touch panel by adjacent circuitry . Accordingly , the concur -
`Not only can the pixels 126 - a and 126 - c where the touch
`rent scan can further include sensing the introduced noise . 15 or hover occurs be affected , but adjacent pixels 126 - b and
`The introduced noise can then be rejected from the touch
`126 - d that are not being touched or hovered over can also be
`panel while the sense signals and coupling signals are being
`affected . Rather than experience no change in capacitance
`Csig , the adjacent pixels 126 - b and 126 - d can give the
`processed .
`USIS
`Some present techniques perform the touch scan and the
`appearance of a so - called " negative pixel ” or a theoretical
`negative pixel scan separately , in sequence , either during a 20 negative amount of touch , i . e . , an increase in Csig . This can
`scan period or during successive scan periods . By perform -
`be because the poorly grounded object can couple some of
`ing the touch and negative pixel scan concurrently , accord -
`the charge from the stimulated pixel 126 - a and 126 - c back
`ing to various embodiments , the touch sensitive device can
`into the panel 124 , which can cause an apparent increase in
`advantageously save processing time and power consump -
`charge at pixel 126 - b and an apparent increase in charge at
`tion , while improving touch and hover sensing , especially 25 pixel 126 - d when the sense lines are scanned for touch
`activity . Accordingly , the Csig signals for the adjacent pixels
`for multiple simultaneous touch or hover events .
`FIG . 1 illustrates an exemplary touch panel that can have
`126 - b and 126 - d can have “ negative pixel ” values captured
`a concurrent touch and negative pixel scan according to
`during the scan .
`various embodiments . In the example of FIG . 1 , touch
`When the drive lines 101 are stimulated , they can capaci
`sensor panel 124 can include an array of pixels 126 that can 30 tively cross - couple with other drive lines through the touch
`be formed at the crossings of rows of drive lines 101
`ing or hovering objects . In this example , stimulated drive
`( DO - D3 ) and columns of sense lines 102 ( SO - S3 ) . The drive
`line DO can capacitively cross - couple ( illustrated by Cdd )
`lines 101 can be used to drive the panel 124 with stimulation
`with drive line D1 through the touching or hovering objects ,
`signals Vstim 116 . The sense lines 102 can be used to
`and with other drive lines D2 , D3 as well . For example , as
`transmit sense signals , in response to the stimulation signals 35 the objects touch or hover over the panel 124 at stimulated
`116 , indicative of a touch or hover at the panel 124 . Each
`pixels 126 - a and 126 - c , cross - coupling between the corre
`pixel 126 can have an associated mutual capacitance Csig
`sponding drive lines DO and D2 can increase . Because of the
`when the drive line 101 forming the pixel is stimulated with
`negative pixel effect , the cross capacitance Cdd can be
`a stimulation signal 116 .
`stronger than it would have been otherwise . The cross
`When an object , e . g . , a finger , touches or hovers over the 40 capacitance Cdd signals on the drive lines can be captured
`panel 124 at the location of the stimulated pixel 126 , the
`during a panel scan for processing by the sense circuitry .
`capacitance Csig can reduce by ACsig due to charge being
`A
`ccordingly , during a panel scan , two capacitance mea
`shunted from the stimulated pixel through the touching or
`surements can be captured cross capacitance Cdd , indica
`hovering object to ground . The reduced Csig can be trans
`tive of the negative pixel effect , and mutual capacitance Csig
`mitted by the associated sense lines 102 and captured during 45 adjusted either by a proper touch or hover or by the negative
`a panel scan for processing by sense circuitry ( not shown ) .
`pixel effect , indicative of a touch or hover at the panel in
`In this example , drive line DO can be stimulated with the
`essence , performing a touch scan and a negative pixel scan
`stimulation signal 116 , forming a mutual capacitance Csig
`concurrently . The cross capacitance Cdd can be used to
`between the stimulated drive line DO and the crossing sense
`determine the negative pixel effect and to compensate the
`lines SO - S3 . When an object touches or hovers over the 50 mutual capacitance Csig therefor . Various embodiments
`panel 124 at stimulated pixel 126 - a formed by drive line DO
`described below can measure Cdd and changes in Csig ,
`and sense line S1 , the mutual capacitance Csig at pixel 126 - a
`determine the negative pixel effect from Cdd , and compen
`sate Csig therefor .
`can be reduced by ACsig .
`In some embodiments , multiple drive lines 101 can be
`Although various embodiments can be described and
`concurrently stimulated with stimulation signals 116 to 55 illustrated herein in terms of multi - touch , mutual capaci
`detect multiple objects , e . g . , multiple fingers , touching or
`tance touch panels , it should be understood that the various
`hovering over the panel 124 . If the objects are properly
`embodiments are not so limited , but can be additionally
`grounded , multiple reduced Csig signals can be transmitted
`applicable to self capacitance panels and single stimulus
`by the associated sense lines 202 and captured during a panel
`touch panels . It should be further understood that the various
`scan for processing by the sense circuitry .
`60 embodiments are not limited to the drive and sense line
`However , if the objects are not properly grounded , they
`configuration described and illustrated herein , but can
`can capacitively couple with the panel 124 , sending some of
`include other configurations according to the needs of the
`the charge from the stimulated pixels 126 back into the
`touch panel .
`panel . As a result , instead of the capacitance Csig being
`FIG . 2 illustrates an exemplary touch sensitive device that
`reduced by ACsig at the pixels 126 where the touch or hover 65 can perform a concurrent touch and negative pixel scan of a
`occurs , Csig can only be reduced by ( ACsig - Cneg ) , where
`touch panel according to various embodiments . In the
`Cneg can represent a so - called “ negative capacitance . "
`example of FIG . 2 , touch sensitive device 200 can include
`
`DELL EXHIBIT 1007 PAGE 14
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`DELL EXHIBIT 1007 PAGE 14
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`

`

`US 9 , 746 , 967 B2
`
`un
`In some embodiments , multiple sense lines 202 can share a
`touch panel 224 , drive circuitry , and sense circuitry . The
`sense amplifier 234 , with a switch between the sense lines
`drive circuitry can include touch buffers 220 coupled to
`and the sense amplifier to sequentially connect each sense
`drive lines 201 of the touch panel 224 to transmit stimulation
`line to the amplifier . During a panel scan , scan logic ( not
`signals Vstim to the panel to drive the panel . Vstim can be
`5 shown ) can control the sense circuitry for capturing and
`either a positive ( + ) phase stimulation signal Vstim + or a
`processing the sense signals .
`negative ( - ) phase stimulation signal Vstim , having the
`The sense circuitry can also include AAF 246 , ADC 248 ,
`same waveform as Vstim + inverted about a common volt
`digital demodulator 242 , and vector operator 244 to process
`age . Each buffer 220 can transmit either Vstim + or Vstim -
`the sense signals . The AAF 246 can receive a sense signal
`based on the drive pattern of the device 200 . In some
`embodiments , the drive pattern can be defined by a stimulus 10 from a sense amplifier 234 and low - pass filter the received
`matrix M , which can include data to generate the stimulation
`signal . The ADC 248 can receive the filtered signal from the
`signals , such as the phases of the stimulation signals for each
`AAF 246 and convert the filtered signal to a digital signal .
`drive line , which drive lines are stimulated concurrently , and
`The digital demodulator 242 can receive a digital sense
`so on . During a panel scan , scan logic ( not shown ) can use
`signal from the ADC 248 and use programmable delay
`the stimulus matrix M data to control the drive pattern .
`15 242 - a to phase shift the sense signal so as to align the signal
`As stated previously , the drive lines 201 can capacitively
`with a demodulation signal generated by a receive NCO ( not
`cross - couple ( illustrated by Cdd ) with each other , either
`shown ) in order to maximize the demodulation gain , mixer
`through the panel 224 or through objects touching or hov
`242 - b to multiply the phase - shifted sense signal with the
`ering over the drive lines . As illustrated in FIG . 2 , the
`demodulation signal so as to demodulate the sense signal ,
`cross - coupling between two drive lines 201 can induce a 20 and integrator 242 - c to integrate the demodulated sense
`voltage Vdd at the output of each touch buffer 220 of the
`signal . The vector operator 244 can receive an integrated
`coupled drive lines . As a result , each buffer 220 can output
`sense signal from the demodulator 242 and output touch
`a composite signal that includes a stimulation signal Vstim
`panel pixel capacitances Cds , indicative of the coupling
`and a drive coupling signal Vdd to drive the touch panel 224 .
`between drive and sense lines , using mixer 244 - a to multiply
`Each buffer 220 can include a resistor Rfb _ tx in a feedback 25 the integrated signal with a decode matrix M ' to decode the
`loop of the buffer to sense the Vdd signal in preparation for
`signal and using integrator 244 - b to integrate the decoded
`negative pixel compensation based on the Vdd signal . The
`sense signal , thereby obtaining the pixel capacitances . In
`voltage drop across the resistor Rfb _ tx , amounting to the
`some embodiments , the decode matrix M ' can be the inverse
`Vdd signal , can be a function of the cross - coupling capaci
`of the stimulus matrix M . The decode matrix M ' can include
`tance Cdd and can be defined as follows .
`30 data for decoding the integrated sense signal . As described
`previously , the drive line cross - coupling can induce a Vdd
`Vdd ( n , m , 5 , 1 ) = WSIMRfb _ tx ( n ) Cdd ( n , m ) . Vstim [ Mín ,
`signal into the panel 224 . As a result , the outputted capaci
`( 1 )
`) - M ( m , s ) ] - cos ( WSTMT ) ,
`tances Cds from the vector operator 244 can include the
`cross - coupling capacitances Cdd and , hence , the negative
`where Vdd ( n , m , s , t ) = voltage across Rfb _ tx ( n ) due to cou
`pling between touch buffer n and touch buffer m
`for panel 35 pixel effect to be compensated for .
`scan step s , WSTy stimulus frequency in radians , Rfb _ tx ( n )
`The digital demodulator 242 and the vector operator 244
`= feedback resistance of touch buffers n and m , Cdd ( n , m )
`can also be used to process the Vdd signals to output the
`= coupling between touch buffers n and m , Vstim = amplitude
`cross - coupling capacitances Cdd , indicative of the negative
`of sinusoidal stimulation signal , M ( n , s ) - touch scan stimulus
`pixel effect . The demodulator 242 can receive a Vdd signal
`matrix M coefficient for touch buffer n and panel scan step 40 from the differential ADC 238 and use the programmable
`s , and M ( m , s ) = touch scan stimulus matrix M coefficient for
`delay 242 - a , the mixer 242 - b , and the integrator 242 - c to
`touch buffer m and panel scan step s . For a given touch
`process the Vdd signal , in the same manner as described
`buffer , a total of r : ( r - 1 ) coupling terms can be resolved ,
`previously regarding the sense signal . The vector operator
`244 can receive an integrated Vdd signal from the demodu
`where r = total number of touch buffers .
`To isolate the sensed Vdd signal , the drive circuitry can 45 lator 242 and , using a cross - coupling matrix N at the mixer
`include multiplexers 222 , differential anti - aliasing filter
`224 - a , output drive line cross - coupling capacitances Cdd . In
`( AAF ) 236 , and differential analog - to - digital converter
`some embodiments , the cross - coupling matrix N can be the
`( ADC ) 238 . Multiplexer 222 - a can receive the downstream
`inverse of the stimulus matrix M . In other embodiments , the
`resistor Vdd signals Vddo of the coupled buffers 220 .
`cross - coupling matrix N can be slightly different from the
`Similarly , multiplexer 222 - b can receive the upstream resis - 50 inverse of the stimulus matrix M , where the cross - coupling
`tor Vdd signals Vddi of the coupled buffers 220 . The
`matrix N can include some data modifications , e . g . , based on
`multiplexers 222 can select one of the Vddo and Vddi
`the stimulation signal Vstim phases between the cross
`signals based on selection signal SEL and can input the
`coupled drive lines . The cross - coupling matrix N can
`selected signals to the AAF 236 and the ADC 238 . The ADC
`include data for decoding the integrated Vdd signal . During
`238 can then output a digital signal proportional to the 55 a panel scan , scan logic ( not shown ) can control the sense
`voltage drop across the resistor , i . e . , the Vdd signal , in
`circuitry for capturing and processing the cross - coupling
`preparation for negative pixel compensation based on the
`signals . An example multi - stimulus demodulation process is
`Vdd signal . In these embodiments , the multiplexers 222 can
`described in
`U . S . Patent Application No . 2010 - 0060593 ,
`allow sharing of the AAF 236 and ADC 238 between
`“ Phase Compensation for Multi - Stimulus Controller . "
`multiple touch buffers 220 . In alternate embodiments , the 60
`A processor ( not shown ) can receive the pixel capaci
`multiplexers 222 can be omitted and each touch buffer 220
`t