US005543591A
`5,543,591
`[11] Patent Number:
`United States Patent
`Gillespie et al.
`[45] Date of Patent:
`Aug. 6, 1996
`
`
`NT AAAEA
`
`[54] OBJECT POSITION DETECTOR WITH 4,148,014—A/1979 Burson sesccssssssssessssssessessssesseee 340/709
`
`EDGE MOTION FEATURE AND GESTURE
`4,198,539
`4/1980 Pepper, Jr.
`wssssssssesssssssasessessnee 178/18
`RECOGNITION
`4,293,734 10/1981 Pepper, Jr.
`eee 178/18
`oo...
`4,302,011
`11/1982 Pepper, Jr.
`ssssssssssssasercssssenen 273/85
`4,313,113
`1/1982. Thomburg ....
`~- 340/709
`4,371,746
`2/1983 Pepper, Jr. ws
`secssessesesseretssesneane 178/18
`4,430,917
`2/1984 Pepper, Jr
`84/1.01
`paee
`Pper
`vr oe
`ee)
`A51L,760
`4/1985 Garwin et al.
`ceccseecsssceseesennee 178/18
`4,734,685
`3/1988 Watanabe ou...ccsesseccceeseresees 340/710
`..eseecesseessesssssreesesen 340/709
`4,766,423
`8/1988 Ono et al.
`
`issssssssssssessesssssne 178/18
`4,918,262
`4/1990 Flowerset al.
`4,988,982
`1/1991 Raymeret al. vesesescsuseeseseeee 345/173
`FOREIGN PATENT DOCUMENTS
`2139762
`11/1984 United Kingdom ....0... GO6F 3/033
`Primary Examiner—Stephen Chin
`Assistant Examiner—Kevin Kim
`Attorney, Agent, or Firm—D’Alessandro & Ritchie
`[57]
`ABSTRACT
`:
`.:
`.
`Methods for recognizing gestures made by a conductive
`object on a touch-sensor pad are disclosed. Tapping, push-
`ing, hopping, and zigzag gestures are recognized by analyz-
`ing the position, pressure, and movementof the conductive
`object on the sensor pad during the time of a suspected
`gesture, and signals are sent to a host indicating the occur-
`rence of these gestures. Signals for compensating for unin-
`tended motion of the conductive object on the touch-sensor
`pad during the gestures are also sent to the host.
`
`[75]
`
`Inventors: David Gillespie, Palo Alto; Timothy P.
`Allen, Los Gatos: Ralph Wolf, Pal
`,
`7
`Nalph
`Wolk,
`Palo
`ll of Calif.
`Alto, a
`.
`.
`[73] Assignee: Synaptics, Incorporated, San Jose,
`Calif.
`
`[21] Appl. No.: 320,158
`[22]
`Filed:
`Oct. 7, 1994
`Related U.S. Application Data
`
`[63] Continuation-in-part of Ser. No. 300,387, Sep. 2, 1994,
`whichis a continuation-in-part of Ser. No. 115,743, Aug. 31,
`1993, Pat. No. 5,734,787, which is a continuation-in-part of
`Ser. No. 895,934, Jun. 8, 1992.
`
`Int. Ce ieecccssessecsssecsssssessesssecceseveccesssvecs GO08C 21/00
`{51]
`[S52] WS. Cd ce ecesseeesetecseenseerneseneseateenstens 178/18, 341/33
`[58] Field of Search oo... ceeceeeees 345/173, 174;
`178/18; 382/3, 13
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS ;
`
`. 178/19
`1/1978 Pepper, Jr.
`.
`12/1978 Pepper, Jr. oon... eeeseceeeeeeeeeseees 178/19
`
`4,071,691
`4,129,747
`
`
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`11 Claims, 26 Drawing Sheets
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`

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`U.S. Patent
`
`Aug.6, 1996
`
`Sheet 1 of 26
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`U.S. Patent
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`Aug. 6, 1996
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`U.S. Patent
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`Aug. 6, 1996
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`U.S. Patent
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`Aug. 6, 1996
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`U.S. Patent
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`Aug. 6, 1996
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`U.S. Patent
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`Aug. 6, 1996
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`U.S. Patent
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`Aug. 6, 1996
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`U.S. Patent
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`Aug.6, 1996
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`Sheet 8 of 26
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`5,543,591
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`U.S. Patent
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`Aug.6, 1996
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`Sheet 9 of 26
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`5,543,591
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`U.S. Patent
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`5,543,591
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`Sheet 10 of 26
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`Aug. 6, 1996
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`U.S. Patent
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`Aug. 6, 1996
`
`Sheet 11 of 26
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`5,543,591
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`U.S. Patent
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`Aug. 6, 1996
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`Sheet 12 of 26
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`5,543,591
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`U.S. Patent
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`Aug. 6, 1996
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`Sheet 13 of 26
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`U.S. Patent
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`Aug. 6, 1996
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`Sheet 14 of 26
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`5,543,591
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`U.S. Patent
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`Aug. 6, 1996
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`Sheet 15 of 26
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`5,543,591
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`

`

`U.S. Patent
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`Aug. 6, 1996
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`Sheet 16 of 26
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`5,543,591
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`TAPOKAY — TRUE
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`

`

`U.S. Patent
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`Aug.6, 1996
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`Sheet 17 of 26
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`5,543,591
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`

`U.S. Patent
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`Aug.6, 1996
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`Sheet 18 of 26
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`

`U.S. Patent
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`Aug. 6, 1996
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`Sheet 19 of 26
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`5,543,591
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`5,543,591
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`Aug. 6, 1996
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`Sheet 20 of 26
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`U.S. Patent
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`

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`U.S. Patent
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`Aug. 6, 1996
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`Sheet 21 of 26
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`5,543,591
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`

`

`U.S. Patent
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`Aug. 6, 1996
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`Sheet 22 of 26
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`5,543,591
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`

`

`U.S. Patent
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`Aug. 6, 1996
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`Sheet 23 of 26
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`5,543,591
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`

`

`U.S. Patent
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`Aug. 6, 1996
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`Sheet 24 of 26
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`5,543,591
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`

`

`U.S. Patent
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`Aug. 6, 1996
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`Sheet 25 of 26
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`5,543,591
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`U.S. Patent
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`Aug. 6, 1996
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`Sheet 26 of 26
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`5,543,591
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`5,543,591
`
`1
`OBJECT POSITION DETECTOR WITH
`EDGE MOTION FEATURE AND GESTURE
`RECOGNITION
`
`RELATED APPLICATIONS
`
`This application is a continuation in part of application
`Ser. No. 08/300,387, filed Sep. 2, 1994, attorney’s Docket
`No. SYN-057A, now allowed, which is a continuation-in-
`part of application Ser. No. 08/115,743, filed Aug. 31, 1993,
`now U.S. Pat. No. 5,734,787, which is a continuation-in-part
`of application Ser. No. 07/895,934,filed Jun. 8, 1992, now
`abandoned.
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`
`The present invention relates to object position sensing
`transducers and systems. More particularly,
`the present
`invention relates to object position recognition useful
`in
`applications
`such as cursor movement
`for computing
`devices and other applications, and especially to cursor
`movement with enhanced edge-motion and gesture-recog-
`nition features.
`2. The Prior Art
`
`Numerous devices are available or have been proposed
`for use as object position detectors for use in computer
`systems and other applications. The most familiar of such
`devices is the computer “mouse”. While extremely popular
`as a position indicating device, a mouse has mechanical pans
`and requires a surface upon which to roll its position ball.
`Furthermore, a mouse usually needs to be moved over long
`distances
`for
`reasonable resolution. Finally, a mouse
`requires the userto lift a hand from the keyboard to makethe
`cursor movement,
`thereby upsetting the prime purpose,
`which is usually typing on the computer.
`Trackball devices are similar to mouse devices. A major
`difference, howeveris that, unlike a mouse device, a track-
`ball device does not require a surface across which it must
`be rolled. Trackball devices arestill expensive, have moving
`parts, and require a relatively heavy touch as do the mouse
`devices. They are also large in size and do not fit well in a
`volume-sensitive application like a laptop computer.
`There are several available touch-sense technologies
`which may be employed for use as a position indicator.
`Resistive-membraneposition sensors are knownand used in
`several applications. However, they generally suffer from
`poorresolution, the sensor surface is exposed to the user and
`is thus subject
`to wear. In addition, resistive-membrane
`touch sensors are relatively expensive. A one-surface
`approach requires a user to be grounded to the sensor for
`reliable operation. This cannot be guaranteed in portable
`computers. An example of a one-surface approach is the
`UnMouse product by MicroTouch, of Wilmington, Mass. A
`two-surface approach has poorer resolution and potentially
`will wear out very quickly in time.
`Resistive tablets are taught by U.S. Pat. No. 4,680,430 to
`Yoshikawa, U.S. Pat. No. 3,497,617 to Ellis and many
`others. The drawback of all such approaches is the high
`power consumption and the high cost of the resistive mem-
`brane employed.
`Surface Acoustic Wave (SAW) devices have potential use
`as position indicators. However, this sensor technology is
`expensive and is not sensitive to light touch. In addition,
`SAW devices are sensitive to residue buildup on the touch
`surfaces and generally have poor resolution.
`
`15
`
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`Strain gauge or pressure plate approachesare an interest-
`ing position sensing technology, but suffer from several
`drawbacks. This approach may employ piezo-electric trans-
`ducers. One drawbackis that the piezo phenomenais an AC
`phenomena and may be sensitive to the user’s rate of
`movement.
`In addition, strain gauge or pressure plate
`approaches are somewhat expensive because special sensors
`are required.
`Optical approaches are also possible but are somewhat
`limited for several reasons. All would require light genera-
`tion which will require external components and increase
`cost and power drain. For example, a “finger-breaking”
`infra-red matrix position detector consumes high power and
`suffers from relatively poor resolution.
`There have been numerous attempts to provide a device
`for sensing the position of a thumborotherfinger for use as
`a pointing device to replace a mouseortrackball. Desirable
`attributes of such a device are low power,low profile, high
`resolution, low cost, fast response, and ability to operate
`reliably when thefingercarries electrical noise, or when the
`touch surface is contaminated with dirt or moisture.
`
`Because of the drawbacks of resistive devices, many
`attempts have been made to provide pointing capability
`based on capacitively sensing the position ofthe finger. U.S.
`Pat. No. 3,921,166 to Volpe teaches a capacitive matrix in
`which the finger changes the transcapacitance between row
`and column electrodes. U.S. Pat. No. 4,103,252 to Bobick
`employs four oscillating signals to interpolate x and y
`positions between four capacitive electrodes. U.S. Pat. No.
`4,455,452 to Schuyler teaches a capacitive tablet wherein
`the finger attenuates the capacitive coupling between elec-
`trodes.
`
`U.S. Pat. No. 4,550,221 to Mabusth teaches a capacitive
`tablet wherein the effective capacitance to “virtual ground”
`is measured by an oscillating signal. Each row or column is
`polled sequentially, and a rudimentary form of interpolation
`is applied to resolve the position between two rows or
`columns. An attempt is made to address the problem of
`electrical interference by averaging over many cycles of the
`oscillating waveform. The problem of contamination is
`addressed by sensing when no finger was present, and
`applying a periodic calibration during such no-finger-present
`periods. U.S. Pat. No. 4,639,720 to Rympalski teaches a
`tablet for sensing the position of a stylus. The stylusalters
`the transcapacitance coupling between row and column
`electrodes, which are scanned sequentially. U.S. Pat. No.
`4,736,191 to Matzke teaches a radial electrode arrangement
`under the space bar of a keyboard,
`to be activated by
`touching with a thumb. This patent teaches the use oftotal
`touch capacitance, as an indication of the touch pressure, to
`control
`the velocity of cursor motion. Pulsed sequential
`polling is employed to address the effects of electrical
`interference.
`
`to Greanias,
`US. Pat. Nos. 4,686,332 and 5,149,919,
`teaches a stylus and finger detection system meant to be
`mounted on a CRT. Asa finger detection system, its X/Y
`sensor matrix is used to locate the two matrix wires carrying
`the maximum signal. With a coding schemethese two wires
`uniquely determine the location of the finger position to the
`resolution of the wire stepping. For stylus detection, Gre-
`anias first coarsely locatcs it, then develops a virtual dipole
`by driving all lines on oneside of the object in one direction
`and all lines on the opposite side in the opposite direction.
`This is done three times with different dipole phases and
`signal polarities. Assuming a predetermined matrix response
`to the object,
`the three measurements present a set of
`simultaneous equations that can be solved for position.
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`5,543,591
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`3
`U.S. Pat. No. 4,733,222 to Evans is the first to teach a
`capacilance touch measurement system that interpolates to a
`high degree. Evans teaches a three terminal measurement
`system that uses a drive, sense and electrode signal set (3
`signals) in its matrix, and bases the measurement on the
`attenuation effect of a finger on the electrode node signal
`(uses a capacitive divider phenomena). Evans sequentially
`scans through each drive set to measure the capacitance.
`From the three largest responses an interpolation routine is
`applied to determine finger position. Evans also teaches a
`zeroing technique that allows “‘no-finger” levels to be can-
`celled out as part of the measurement.
`U.S. Pat. No. 5,016,008 to Gruaz describes a touch
`sensitive padthat also uses interpolation. Gruaz uses a drive
`and sense signal set (2 signals) in the touch matrix and like
`Evansrclics on the attenuation effectof a finger to modulate
`the drive signal. The touch matrix is sequentially scanned to
`read the response of each matrix line. An interpolation
`program then selects the twolargest adjacentsignals in both
`dimensions to determinethe finger location, and ratiometri-
`cally determines the effective position from those 4 num-
`bers.
`
`Gerpheide, PCT application US90/04584, publication No.
`W091/03039, U.S. Pat. No. 5,305,017 applies to a touch pad
`system a variation of the virtual dipole approach of Grean-
`ias. Gerpheide teaches the application of an oscillating
`potential of a given frequency and phasetoall electrodes on
`one side of the virtual dipole, and an oscillating potential of
`the same frequency and opposite phase to those on the other
`side. Electronic circuits develop a “balance signal” whichis
`zero when nofinger is present, and which has one polarity
`if a finger is on one side ofthe center of the virtual dipole,
`and the opposite polarity if the finger is on the oppositeside.
`To acquire the position of the finger initially,
`the virtual
`dipole is scanned sequentially across the tablet. Once the
`fingeris located,it is “tracked” by movingthe virtual dipole
`toward the finger once the finger has moved more than one
`row or column.
`
`Becausethe virtual dipole method operates by generating
`a balance signal that is zero when the capacitance does not
`vary with distance,it only senses the perimeterof the finger
`contact area, rather than the entire contact area. Because the
`method relies on synchronous detection of the exciting
`signal, it must average for long periodsto reject electrical
`interference, and hence it
`is slow. The averaging time
`required by this method,
`together with the necessity to
`search sequentially for a new finger contact once a previous -
`contact is lost, makes this method, like those before it, fall
`short of the requirementsfor a fast pointing device that is not
`affected by electrical interference.
`It should also be noted that all previous touch pad
`inventions that used interpolation placed rigorous design
`requirements on their sensing pad. Greanias and Evans use
`a complicated and expensive drive, sense and electrode line
`scheme to develop their signal. Gruaz and Gerpheide use a
`two signal drive and senseset. In the present invention the
`driving and sensing is done on the samclinc. This allows the
`tow and column sections to be symmetric and equivalent.
`This in turn allows independent calibration of all signal
`paths, which makes board layout simpler and less constrain-
`ing, and allows for more unique sensor topologies.
`The shortcomings of the inventions and techniques
`describedin the prior art can also be traced to the use of only
`one set of driving and sensing electronics, which was
`multiplexed sequentially over the electrodes in the tablet.
`This arrangement wascost effective in the days of discrete
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`components, and avoided offset and scale differences among
`circuits.
`
`The sequential scanning approach of previous systems
`also made them more susceptible to noise. Noise levels
`could change between successive measurements,
`thus
`changing the measured signal and the assumptions used in
`interpolation routines.
`Finally, all previous approaches assumed a particular
`signal response for finger position versus matrix position.
`Because the transfer curve is very sensitive to many param-
`eters and is not a smooth linear curve as Greanias and
`Gerpheide assume, such approaches are limited in the
`amount of interpolation they can perform.
`In prior co-pending application Ser. No. 08/115,743, filed
`Aug. 31, 1993, now U.S. Pat. No. 5,734,787, a two-dimen-
`sional capacitive sensing system equipped with a separate
`set of drive/sense electronics for each row and for each
`column ofa capacitive tablet is disclosed. All row electrodes
`are sensed simultaneously, and all column electrodes are
`sensed simultaneously. The sensed signals are processed by
`analog circuitry.
`Of the touchpad devices currently available, only the
`Alps/Cirque GlidePoint includes gesture recognition. The
`GlidePoint supports basic tap, double-tap, and drag gestures
`to simulate actions on a primary mouse button. It does not
`support multiple-finger gestures, nor are there gestures for
`simulating secondary button clicks. No information is
`known about the implementation methods employed in the
`GlidePoint. However,
`the GlidePoint
`is known to have
`difficulty with double-taps, one of the problems addressed
`by the present invention. The GlidePoint exhibits a hesita-
`tion on each finger-motion stroke which may be an attempt
`to stabilize the cursor during tap gestures. Also, the Glide-
`Point must rely on physical switches or extremely high gain
`or acceleration in order to allow drags over long distances.
`One touchpad product, the UnMouse, mounts a switch
`underneath its resistive sensorso that the user simply presses
`downon the pad to activate the button. Aside from requiring
`fragile and complex mechanical mounting, this device also
`is reported to be very tiring to the user.
`Graphics tablets operated by a pressure sensitive stylus
`instead of a finger are well-knownin theart. These devices
`typically use a mechanism like the “push” gesture of the
`present invention to simulate actuator switches. No other
`gestures of the sort described herein have been seen in
`stylus-operated tablets.
`It is thus an object of the present invention to provide a
`two-dimensional capacitive sensing system cquipped with a
`separate set of drive/sense electronics for each row and for
`each column of a capacitive tablet, wherein all row elec-
`trodes are sensed simultaneously, and ali column electrodes
`are sensed simultaneously.
`It is a further object of the present invention to provide an
`electronic system that is sensilive to the entire area of
`contact of a finger or other conductive object with a capaci-
`tive tablet, and to provide as output the coordinates of some
`measure of the center of this contact area while remaining
`insensitive to the characteristic profile of the object being
`detected.
`
`It is a further object of the presentinvention to provide an
`electronic system that provides as output some measure of
`area of contact ofa finger or other conductive object with a
`capacitive tablet.
`Yet another object of the present inventionis to provide a
`two-dimensional capacitive sensing system equipped with a
`
`

`

`5,543,591
`
`5
`separate sct of drive/sensc electronics for each row and for
`each column of a capacitive tablet, wherein all row elec-
`trodes are sensed simultaneously, and all column electrodes
`are sensed simultaneously and whcercin the information
`defining the location of a finger or other conductive object
`is processed in digital form.
`It is a further object of the present invention to provide a
`two-dimensional capacitive sensing system wherein all row
`electrodes arc sensed simultaneously, and all column elec-
`trodes are sensed simultaneously and wherein the location of
`a fingeror other conductive object within a peripheral region
`of a sensing plane can optionally causc cursor “edge
`motion” ona display screen allowing controlof large cursor
`excursions from a small sensing plane with a single gesture.
`A further object of the invention is to provide for the
`recognition of gestures made by a finger or other object on
`a touch-sensor pad in a manner which compensates for
`unintended motion of the finger or other object during
`expression of the gesture.
`Yet another object of the present invention is to provide
`for the recogntion of multiple-finger gestures and for simu-
`lating secondary button clicks.
`
`BRIEF DESCRIPTION OF THE INVENTION
`
`With the advent of very high levels of integration,it has
`become possible to integrate many channels of driving/
`sensing electronics into one integrated circuit, along with the
`control logic for operating them, and the interface electron-
`ics to allow the pointing device to communicate directly
`with a host microprocessor. The present
`invention uses
`adaptive analog techniques to overcome offset and scale
`differences between channels, and can thus sense either
`transcapacitance or self-capacitance of all tablet rows or
`columnsin parallel. This parallel-sensing capability, made
`possible by providing one set of electronics per row or
`column,allowsthe sensing cycle to be extremely short, thus
`allowing fast response while still maintaining immunity to
`very high levels of electrical interference.
`The present invention comprises a position-sensing tech-
`nology particularly useful for applications where finger
`position information is needed,
`such as
`in computer
`“mouse”or trackball environments. However the position-
`sensing technology of the present invention has much more
`general application than a computer mouse, because its
`sensor can detect and report if one or more points are being
`touched. In addition, the detector can sense the pressure of
`the touch.
`
`According to a preferred embodiment of the present
`invention, referred to herein as a “finger pointer” embodi-
`ment, a position sensing system includesa position sensing
`transducer comprising a touch-sensitive surface disposed on
`a substrate, such as a printed circuit board,
`including a
`matrix of conductive lines. A first set of conductive lines
`runs in a first direction and is insulated from a secondset of
`conductive lines running in a second direction generally
`perpendicular to the first direction. An insulating layer is
`disposed over the first and second sets of conductive lines.
`The insulating layer is thin enough to promote significant
`capacitive coupling between a finger placed on its surface
`and the first and second sets of conductive lines.
`
`Sensing electronics respond to the proximity of a finger,
`conductive object, or an object of high dielectric constant
`(i.c., greater than about 5) to translate the capacitance
`changes of the conductors caused by object proximity into
`digital information which is processedto derive position and
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`touch pressure information. Its output is a simple X, Y and
`pressure value of the one object on its surface. In all
`descriptions herein,fingers are to be considered interchange-
`able with conductive objects and objects of high dielectric
`constant.
`
`Different prior art pad scan techniques have different
`advantages in different environments. Parallel drive/sense
`techniques according to the present invention allow input
`samples to be taken simultaneously, thus all channels are
`affected by the same phaseof an interfering electrical signal,
`greatly simplifying the signal processing and noisefiltering.
`There are two drive/sense methods employedin the touch
`sensing technology of the present invention. According to a
`first and presently preferred embodiment of the invention,
`the voltages on all of the X lines of the sensor matrix are
`simultaneously moved, while the voltages of the Y lines are
`held at a constant voltage, with the complete set of sampled
`points simultaneously giving a profile of the finger in the X
`dimension. Next, the voltages on all of the Y lines of the
`sensor matrix are simultaneously moved, while the voltages
`of the X lines are held at a constant voltage to obtain a
`complete set of sampled points simultaneously giving a
`profile of the finger in the other dimension.
`According to a second drive/sense method, the voltages
`on all of the X lines of the sensor matrix are simultaneously
`moved in a positive direction, while the voltages of the Y
`lines are movedin a negative direction. Next, the voltages on
`all of the X lines of the sensor matrix are simultaneously
`moved in a negative dircction, while the voltages of the Y
`lines are moved in a positive direction. This technique
`doubles the effect of any transcapacitance between the two
`dimensions, or conversely, halves the effect of any parasitic
`capacitance to ground. In both methods,
`the capacitive
`information from the sensing process provides a profile of
`the proximity of the finger to the sensor in each dimension.
`Aspresently preferred, both embodiments then take these
`profiles and derive a digital value representing the centroid
`for X and Y position and derive a second digital value for the
`Z pressure information. The digital information may be
`directly used by a host computer. Analog processing of the
`capacitive information may also be used according to the
`present invention.
`The position sensor of these embodiments can only report
`the position of one object on its sensor surface. If more than
`one object is present, the position sensorof this embodiment
`computes the centroid position of the combined set of
`objects. However, unlike prior art, because the entire pad is
`being profiled, enough information is available to discern
`simple multi-finger gestures to allow for a more powerful
`user interface.
`
`According to another aspect of the present invention,
`several powerreduction techniques which can shut downthe
`circuit between measurements have been integrated into the
`system. This is possible because the parallel mcasurement
`technique according to the present invention is so much
`faster than prior art techniques.
`According to a further aspect ofthe invention, a variety of
`noise reduction techniques are integrated into the system.
`According to yet another aspect of the present invention,
`a capacitance measurement technique which is easier to
`calibrate and implement is employed.
`According to another aspect of the present invention,
`when the presence of a finger or other conductive object is
`sensed within a defined peripheral region of the sensing
`plane, the control of cursor motion may be changed to
`provide “edge motion” to allow control of large cursor
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`

`

`5,543,591
`
`7
`excursions on a display screen from a single gesture
`executed on a small sensing plane.
`According to a further object of the present invention, a
`numberof gestures made by a finger or other object on the
`touch-sensor pad are recognized and communicated to a
`host. Compensation for unintended motion ofthe finger or
`other object during expression of the gestures is provided.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is an overall block diagram of the capacitive
`position sensing system of the present invention.
`FIG. 2a is a top view of an object position sensor
`transducer according to a presently preferred embodiment of
`the invention showing the object position sensor surface
`layer including a top conductive trace layer and conductive
`pads connected to a bottom trace layer.
`FIG. 2b is a bottom view of the object position sensor
`transducer of FIG. 2a showing the bottom conductive trace
`layer.
`FIG. 2c is a composite view of the object position sensor
`transducer of FIGS, 2a and 2b showing both the top and
`bottom conductive trace layers.
`FIG. 2d is a cross-sectional view of the object position
`sensor transducer of FIGS. 2a—2c.
`
`FIG. 3 is a block diagram of sensor decoding electronics
`which maybe used with the sensor transducerin accordance
`with a preferred embodimentof the present invention.
`FIG. 4a is a simplified schematic diagram of a charge
`integrator circuit which may be used in the present inven-
`tion.
`
`FIG.4bis an illustrative schematic diagram of the charge
`integrator circuit of FIG. 4a.
`FIG. 5 is a timing diagram of the operation of charge
`integrator circuit of FIGS. 4a and 4b.
`FIG.6 is a schematic diagram of an illustrative filter and
`sample/hold circuit for use in the present invention.
`FIG. 7 is a more detailed block diagram of a presently
`preferred arrangement of A/D converters for use in the
`present invention.
`FIG.8 is a block diagram ofan illustrative arithmetic unit
`which may be used in the present invention.
`FIG. 9 is a block diagram of a calibration unit which may
`be used with the arithmetic unit of FIG.8.
`
`FIG. 10 is a schematic diagram of a bias voltage gener-
`ating circuit useful in the present invention.
`FIG. 11 is a diagram of the sensing plane illustrating the
`edge motion feature of the object position sensor of the
`present invention.
`FIG. 12 is a schematic diagram illustrating hardware
`implementation of the determination of whether a finger or
`other object is present
`in the peripheral regions of the
`sensing plane.
`FIG. 13 is a schematic diagram illustrating hardware
`implementation of the edge motion feature of the present
`invention.
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`FIG. 14 is a more detailed block diagram of gesture unit
`20 of FIG. 1.
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`FIGS. 15a through 15e are timing diagramsillustrating
`some of the gestures which may be recognized according to
`the present invention.
`FIGS. 16a and 165 are diagramsillustrating two tap zone
`shapes which may be used on sensor pads according to the
`present invention.
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`FIGS, 17a through 17f comprise a flowchart illustrating
`the operation of the tap unit of FIG. 14.
`FIGS. 18a through 18c comprise a flowchart illustrating
`the the operation of the zigzag unit of FIG. 14.
`FIG.19 is a timing diagram illustrating a “push” gesture
`according to the present invention.
`FIG. 20 is a flowchart illustrating the the operation of the
`push unit of FIG. 14.
`FIG. 21 is a block diagram ofan illustrative Lift Jump
`supressor circuit which may be used in gestrure recognition
`according to the present invention.
`
`DETAILED DESCRIPTION OF A PREFERRED
`EMBODIMENT
`
`This application is a continuation-in-part of co-pending
`application Ser. No. 08/300,387,filed Sep. 2, 1