AONEAA5 20040252109A
`
`as) United States
`a2) Patent Application Publication co) Pub. No.: US 2004/0252109 Al
`Trent, JR. et al. Dec. 16, 2004 (43) Pub. Date:
`
`
`
`(54) CLOSED-LOOP SENSOR ON A SOLID-STATE
`OBJECT POSITION DETECTOR
`
`Related U.S. Application Data
`
`(75)
`
`Inventors: Raymond A. Trent JR., San Jose, CA
`(US); Scott J. Shaw, Fremont, CA
`(US); David W. Gillespie, Los Gatos,
`CA (US); Christopher Heiny, Boulder
`Creek, CA (US); Mark A. Huie, San
`Carlos, CA (US)
`Correspondence Address:
`SIERRA PATENT GROUP, LTD.
`PO BOX 6149
`STATELINE, NV 89449 (US)
`
`(73) Assignee: Synaptics, Inc.
`
`(21) Appl. No.:
`
`10/338,765
`
`(22)
`
`Filed:
`
`Jan. 7, 2003
`
`(60) Provisional application No. 60/372,009,filed on Apr.
`11, 2002.
`
`Publication Classification
`
`(SL) Unt. C1? ie eeecccssesteteeceesnneeee GOIG 5/00
`(82) WSMOL wasccusasauncaunannnnoun. SASTIA
`Ov)
`.
`ae ae .
`.
`The present disclosure discloses an object position detector.
`The object position detector comprises a
`touch sensor
`formed as a closed loop and having a physical constraint
`formed on an upper surface of the touch sensor and coex-
`tensive with the closed loop. The touch sensoris configured
`to sense motion of an object proximate to the closed loop.
`The object position detector also comprises a processor
`coupledto the touch sensor and is programmed to generate
`an action in response to the motion on the touch sensor.
`
`CYPRESS 1005
`CYPRESS 1005
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`Patent Application Publication Dec. 16,2004 Sheet 1 of 17
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`6
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`xt
`12
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`Closed
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`Loop Path
`HienaES
`Host
`Generator
`Device
`Decoder
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`Patent Application Publication Dec. 16,2004 Sheet 2 of 17
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`Patent Application Publication Dec. 16,2004 Sheet 3 of 17
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`«cs A D A
`Cr
`Fig. 11 Fig.12 Fig. 13 Fig. 14 Fig. 15
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`Fig. 16
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`Patent Application Publication Dec. 16,2004 Sheet 4 of 17
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`*
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`File |
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`5
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`Patent Application Publication Dec. 16,2004 Sheet 5 of 17
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`Fig. 28
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`eSatent Application Publication Dec. 16, 2004 Sheet 6 of 17
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`Patent Application Publication Dec. 16,2004 Sheet 7 of 17
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`Fig. 31
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`8
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`Patent Application Publication Dec. 16,2004 Sheet 8 of 17
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`inCapacitance
`Change
`
`X or Y Axis Sensor Inputs
`
`Fig. 32
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`9
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`Patent Application Publication Dec. 16,2004 Sheet 9 of 17
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`34
`i
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`|
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`110
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`at
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`115
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`114
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`112
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`116
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`'
`<—_—
`34
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`Fig. 33
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`10
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`Patent Application Publication Dec. 16,2004 Sheet 10 of 17
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`11
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`11
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`Patent Application Publication Dec. 16,2004 Sheet 11 of 17
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`Capacitance
`
`
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`Measurement————?
`
`C(0)
`
`Cd)
`
`CQ)
`i-|
`
`C(3)
`i
`
`c(4)
`itl
`
`C(5)
`
`Fig. 40
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`12
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`12
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`Patent Application Publication Dec. 16,2004 Sheet 12 of 17
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`Determine which electrode has
`the largest capacitance
`Measurement
`
`Fit capacitance measurements of
`electrode with largest capacitance
`and its neighboring electrodes to an
`inverted parabola
`
`Calculate the center point
`of the parabola
`
`compensate for non-linearities
`
`Reduce the calculated center
`point by Modulo N, if necessary
`
`Pass calculated center point value
`through a non-linear function to
`
`Fig. 39
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`13
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`Patent Application Publication Dec. 16,2004 Sheet 13 of 17
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`Locate peak electrode 7
`
`Rotate coordinate system by renumbering
`each electrode j to (j-it+N/2) Modulo N,
`thus centering i
`
`
`
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`
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`
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`Calculate mathematical centroid X
`
`Reverse rotate X’=(X+i-N/2) Modulo N,
`X’ is final input object location
`
`Fig. 41
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`14
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`Patent Application Publication Dec. 16,2004 Sheet 14 of 17
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`US 2004/0252109 Al
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`obtain angular position
`
`Compute denominator D as
`D= Sum(cos(i*2 pi/N) * C(y)
`
`Compute numerator N as
`N= Sum(sin(i*2 pi/N) * C(i)
`
`Compute atan2(N,D) to
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`Patent Application Publication Dec. 16,2004 Sheet 15 of 17
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`US 2004/0252109 Al
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`Compute numerator N as
`Nfs
`
`angular position
`
`Compute denominator D as
`pH
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`Compute/,(N,D) to obtain
`
`Fig, 43
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`16
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`Patent Application Publication Dec. 16,2004 Sheet 16 of 17
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`Calculate NewPos
`
`
`
`Was an
`
` Copy NewPos
`
`
`object previously present
`
` into OldPos
`on the sensor?
`
`
`
`Determine motion between
`
`
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`two samples ( Motion = NewPos - OldPos)
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`Motion is
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`180° or
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`
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`more ?
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`Motion is
`Less than
`-180°
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`9
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`Subtract 360°
`from Motion
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`
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`Add 360°
`to Motion
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`Fig.44
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`17
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`Patent Application Publication Dec. 16,2004 Sheet 17 of 17
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`Determinea first point and a
`second point on the closed
`loop sensor
`
`Calculate the distance between
`the first and second points
`
`indicate direction of motion
`
`Calculate the angles corresponding
`to the first and second points
`
`Subtract the angle of the second point
`from the angle ofthe first point to
`get a result
`
`Use the sign of the result to
`
`Fig. 45
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`US 2004/0252109 Al
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`Dec. 16, 2004
`
`CLOSED-LOOP SENSOR ON A SOLID-STATE
`OBJECT POSITION DETECTOR
`
`CROSS-REFERENCE TO RELATED
`APPLICATION
`
`[0001] This application claims the benefit of U.S. Provi-
`sional Application Serial No. 60/372,009, filed Apr. 11,
`2002.
`
`BACKGROUND
`
`[0002] User interfaces on digital information processing
`devices often have more information and options than can be
`easily handled with buttons or other physical controls. In
`particular, scrolling of documents and data, selection of
`menu items, and continuous value controls, such as volume
`controls, can be difficult to control with buttons and general
`purpose pointing devices. These buttons and pointing
`devices are inherently limited in how far they can move or
`how many options can be selected. For example, a computer
`mouse, though it can move a pointer or cursor indefinitely,
`has limits to how far it can move without being picked up
`and repositioned, which limits its usability in these situa-
`tions.
`
`[0003] Solutions to this problem have included:
`
`a. Keys, such as “page up” and “page down”
`[0004]
`and arrow keys, that are specifically designated to
`maneuver through or control data;
`
`_b. Provisions for scrollbars in a user interface
`[0005]
`which can be used toscroll data long distances by
`using a standard computer pointing device control-
`ling a cursor;
`
`c. Similarly controlled (as in b.) hierarchical
`[0006]
`menus or choices;
`
`d. Graphical user interface elements such as
`[0007]
`“slider bars” and “spin controls”to vary a parameter
`over an arbitrary range;
`
`©. Scrolling “wheels” on standard pointing
`[0008]
`devices;
`
`f. Physical knob controls, which, when used to
`[0009]
`control a user interface are often referred to in the art
`as “jog dials”. Some knobsand dials output quadra-
`ture signals to indicate direction of motion;
`
`rely on optically or
`that
`g. Trackballs
`[0010]
`mechanically sensed spherical controls to provide
`two-dimensional sensing; and
`
`h. Acapacitive two-dimensional object posi-
`[0011]
`tion sensor that can be usedfor scrolling by provid-
`ing a “scrolling region”, where users can slide their
`fingers to generating scrolling actions.
`
`[0012] The disadvantages of these prior solutions are as
`follows:
`
`a. Designated Keys: These typically require
`[0013]
`designated space on the keyboard as well as sup-
`porting electronics and physical structures. Keys
`usually limit the control they offer to the user over
`the information being scrolled or the function being
`performed to distinct values. For example, page up
`
`19
`
`and page down keys enable the user to increment
`through a document at a constant rate of page by
`page only.
`[0014]
`b. Scroll bars controlled by a pointing device
`and a cursor: These elements require the user to
`move long distances across a display and/or select
`relatively small controls in order to scroll the data.
`Additionally, these scroll bars take up room on the
`display that can be used for other purposes.
`[0015]
`c. Hierarchical menuscontrolled by a pointing
`device or by key combinations: These have a similar
`problem to scroll bars, in terms of the complexity of
`ithe targeting task that faces the user. First, the user
`must hit a small target near the edge of a screen, and
`then the user must navigate along narrow paths to
`open up additional layers of menu hierarchy. Short-
`cut keys, which usually consist of key combinations,
`are typically non-intuitive and hard to remember.
`[0016]
`d. “Sliders” and “spin controls” controlled by
`a pointing device or by key combinations: These
`have targeting problems similar to scroll bars and
`hierarchical menus (sometimes exacerbated by the
`targets usually being even smaller than in the cases
`of scrollbars and menus).
`[0017]
`e. Physical Scroll Wheels on mice: The user is
`unable to scroll very far with these wheels due to
`mechanical limitations in how far the user can move
`the wheel
`in a single stroke. These mechanical
`limitations are because of the construction of the
`wheel itself or because of interactions between the
`
`wheel and nearby physical features (such as the
`wheel mounting or the device housing). The limits
`on the practical/comfortable length of the basic fin-
`ger motion also severely restrict the ability of the
`user to scroll significant distances in one stroke.
`Additionally, these wheels are mechanically com-
`plex and take up a lot of space.
`[0018]
`f. Physical knobs or “Jog Dial” controls:
`These have the disadvantages of being relatively
`large and mechanically complex. Similar to the
`scroll wheel, the knob or dial requires some amount
`of
`friction to limit accidental activation, which
`increases the difficulty offine adjustments. Addition-
`ally, it is difficult to use a physical knob or dial with
`a great degree of accuracy, and the knob or dial
`inherently has inertia that may cause overshoot in
`large motions. The physical knobs or dials are often
`mechanically limited in range of rotation imposed by
`the construction or by the interactions of the knob or
`dial with nearby physical features.
`[0019]
`g. Trackballs: These are similar to the physical
`knobs in that they have the disadvantages of being
`bulky and mechanically complex. The trackball is
`difficult to use with a great degree of accuracy, and
`the trackball inherently has inertia that may cause
`overshoot in large motions. Additionally, the track-
`ball presents additional complexity in that it presents
`control of two dimensions of motion in a way that
`makes it difficult for users to limit their inputs to a
`single dimension. Finally, the input is limited either
`by the construction of the trackball and its housing,
`or by natural limits on comfortable/practical finger
`motion, or both.
`
`19
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`US 2004/0252109 Al
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`Dec. 16, 2004
`
`h. Scroll Regions: These are limited by the
`[0020]
`physical limitation that a user’s finger will eventually
`reach the end of the scrolling region and the user will
`havetolift their finger, replace it on the sensorinside
`the region, and continue the motion. The user must
`perform many repetitive motions of the same finger
`to scroll long distances with a scroll region.
`
`[0021] The disadvantages of the prior art can be remedied
`by devising a userinterface that enablesscrolling,selecting,
`and varying controls over a long range of possible positions
`and values.
`
`SUMMARY
`
`(0022] The drawbacks and disadvantages ofthe prior art
`are overcomebya closed-loop sensor on a solid-state object
`position detector.
`
`[0023] The present disclosure discloses a solid-state object
`position detector. The solid-state object position detector
`comprises a touch sensor formed as a closed loop having a
`physical constraint formed on an upper surface of the touch
`sensor and coextensive with the closed loop. The touch
`sensoris configured to sense motion ofan object proximate
`to the closed loop. The object position detector also com-
`prises a processor coupled to the touch sensor and is
`programmed to generate an action in response to the motion
`on the touch sensor.
`
`[0024] The present disclosure also discloses a solid-state
`object position detector, comprising a
`two-dimensional
`touch sensor having a tactile guide formed on an upper
`surface of, and coextensive with, the two-dimensional touch
`sensor. The two-dimensional touch sensor is configured to
`sense motion of an object proximate to the two-dimensional
`touch sensor. The solid-state object position detector also
`comprises a processor coupled to the two-dimensional touch
`sensor and configured to report only one variable indicating
`the position, such as the angular position, of an object
`proximate to the two-dimensional touch sensor. The proces-
`sor is programmed to generate an action in response to the
`motion on the two-dimensional touch sensor.
`
`[0025] The present disclosure also discloses a combina-
`tion comprising a solid-state object position detector, a
`pointing input device, and a processor. The solid-state object
`position detector has a touch sensor formed as a closed loop.
`The solid-state object position detector has a tactile guide
`formed on an upper surface of the touch sensor and coex-
`tensive with the closed loop. The touch sensor is configured
`to sensea first position of an object proximate to the closed
`loop. The pointing input device is disposed proximate to the
`solid-state object position detector and is configured to sense
`a first pointing input of a user. The processor is coupled to
`the solid-state object position detector and to the pointing
`input device. The processor is programmed to generate at
`least one action in responseto the first position and at least
`one action in response to the first pointing input. The
`pointing input device can be a mouse, a touch pad,a pointing
`stick, a slider, a joystick, a touch screen, a trackball or
`another solid-state object position detector.
`
`[0026] The present disclosure also discloses another
`embodiment of a combination comprising a solid-state
`object position detector, a control input device, and a pro-
`cessor. The solid-state object position detector has a touch
`
`sensor formed as a closed loop. The solid-state object
`position detector has a tactile guide formed on an upper
`surface of the touch sensor and coextensive with the closed
`loop. The touch sensor is configured to sense a first position
`of an object proximate to the closed loop. The control-input
`device is disposed proximate to the solid-state object posi-
`tion detector andis configured to sensea first control input
`of a user. The processor is coupled to the solid-state object
`position detector and to the control input device. The pro-
`cessor is programmed to generate at
`least one action in
`response to the first position and at
`least one action in
`response to the first control input. The control input device
`can be a button, a key, a touch sensitive zone, a scrolling
`region, a scroll wheel, a jog dial, a slider, a touch screen, or
`another solid-state object position detector.
`
`[0027] The present disclosure also discloses a solid-state
`object position detector, comprising a touch sensor having a
`first electrode and a plurality of second electrodes disposed
`in a one-dimensional closed loop and proximate to the first
`electrode. The solid-state object position detector also com-
`prises a processor coupledto the touch sensor. The processor
`generates an action in response to user input on the touch
`sensor. The complexity of the sensing circuitry used in the
`plurality of second electrodes can be reduced, such that
`when only relative positioning is necessary, at least two of
`the plurality of secondelectrodes are electrically connected
`or wired together.
`
`[0028] The present disclosure also discloses a combina-
`tion comprising a solid-state object position detector, a touch
`pad, and a processor. The solid-state object position detector
`comprises a touch sensor having a first electrode and a
`plurality of second electrodes disposed in a one-dimensional
`closed loop and proximate tothe first electrode. The touch
`pad has a plurality of X electrodes and a plurality of Y
`electrodes. The first electrode is electrically coupled to at
`least one of the plurality of X electrodes and the plurality of
`Y electrodes. The processor is coupled to the touch sensor
`and to the input device. The processor generates an action in
`response to user input on at least one of the touch sensor and
`ihe touch pad. The complexity of the sensing circuitry used
`in the plurality of second electrodes can be reduced, such
`that when only relative positioning is necessary, at least two
`of the plurality of second electrodes are electrically con-
`nected or wired together.
`
`[0029] The present disclosure also discloses a solid-state
`object position detector, comprising a touch sensor having a
`plurality of interleaving electrodes disposed proximate to a
`one-dimensional closed loop; wherein each electrode is
`interdigitated with an adjacent neighboring electrode. The
`solid-state object position detector also comprises a proces-
`sor coupled to the touch sensor. The processor generates an
`action in response to user input on the touch sensor.
`
`[0030] The present disclosure also discloses a solid-state
`object position detector, comprising a touch sensor having a
`plurality of self-interpolating electrodes disposed proximate
`to a closed loop. The solid-state object position detector also
`comprises a processor coupled to the touch sensor. The
`processor generates an action in response to user input on the
`touch sensor.
`
`[0031] The present disclosure also discloses a method of
`calculating a position of an object on an object position
`detector comprising receiving positional data from the
`
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`US 2004/0252109 Al
`
`Dec. 16, 2004
`
`object on a touch sensor having a closed loop and interpo-
`lating the positional data to determine a position of the
`object on the one-dimensional closed loop. The interpolating
`aspect of the method further includes performing a quadratic
`fitting algorithm, a centroid interpolation algorithm, a trigo-
`nometric weighting algorithm, or a quasi-trigonometric
`weighting algorithm.
`
`[0032] The present disclosure also discloses a method of
`determining motion of an object on a touch sensor of an
`object position detector. The method comprises receiving
`data of a first position of the object on a closed loop on a
`touch sensorof the object position detector, receiving data of
`a second position of the object on the closed loop, and
`calculating motion from the second position andthe first
`position. The method can further comprise determining if
`the motion is equal to or greater than a maximum angle and
`adjusting the motion based on whether the motion is equal
`or greater than the maximum angle. The method of adjusting
`the motion can be subtracting 360° from the motion. The
`method can further comprise determining if the motion is
`less than a minimum angle and adjusting the motion based
`on whether the motion is less than the minimum angle. The
`method of adjusting the motion can be adding 360° to the
`motion.
`
`BRIEF DESCRIPTION OF FIGURES
`
`[0033] Referring now tothe figures, wherein like elements
`are numbered alike:
`
`FIG. 1 illustrates a block diagram ofa solid-state
`[0034]
`closed-loop sensor;
`
`FIG.2 illustrates a location of a closed-loop sensor
`[0035]
`on a laptop near a keyboard;
`
`FIG.3 illustrates a closed-loop sensor disposed on
`[0036]
`a conventional pointing device;
`
`[0037] FIG. 4 illustrates wedge-shaped electrodes of a
`closed-loop sensor;
`
`FIG.5 illustrates lightning-bolt-shaped electrodes
`[0038]
`of a closed-loop sensor;
`
`[0039] FIG. 6 illustrates triangle-shaped electrodes of a
`closed-loop sensor;
`
`[0040] FIG. 7 illustrates rectangular-shaped electrodes
`that may be used in a linear section of a closed-loop sensor;
`
`[0041] FIG. 8 illustrates rectangular-shaped electrodes
`that may be used ina rectangular-shaped closed-loop sensor;
`
`[0042] FIG. 9 illustrates another example of triangle-
`shaped electrodes of a closed-loop sensor;
`
`(0043] FIG. 10 illustrates spiral-shaped electrodes of a
`closed-loop sensor;
`
`FIGS. 11 to 17 illustrate various shapes of the path
`[0044]
`utilized on a closed-loop sensor;
`
`[0047] FIG. 20 illustrates a cross-sectional view of
`U-shaped depressed grooves that define the path on a
`closed-loop sensor;
`
`FIG.21 illustrates a cross-sectional view of a bezel
`[0048]
`that defines the path on a closed-loop sensor;
`
`[0049] FIGS. 22 and 23 illustrate the motions of an input
`object on a closed-loop sensor and the effects on a host
`device;
`
`[0050] FIG. 24 illustrates a motion on a closed-loop
`sensor for navigating menus;
`
`[0051] FIG. 25 illustrates a motion on a closed-loop
`sensor for vertically navigating menus using an additional
`key;
`
`[0052] FIG. 26 illustrates a motion on a closed-loop
`sensor for horizontally navigating within open menus;
`
`[0053] FIG. 27 illustrates a motion on a closed-loop
`sensor for a value setting control;
`
`[0054] FIG. 28 illustrates a closed-loop sensorelectrically
`connected to a touch pad;
`
`(0055] FIG, 29 illustrates the potential electrical connec-
`tions of two closed-loop sensors to a touch pad;
`
`[0056] FIG. 30 illustrates several closed-loop sensors
`electrically connected to a touch pad;
`
`[0057] FIG. 31 illustrates two closed-loop sensors with
`indicator electrodes electrically connected to a touch pad;
`
`[0058] FIG. 32 illustrates a graph of the signals from a
`closed-loop sensor with an indicator electrode electrically
`connected to a touch pad;
`
`(0059] FIG. 33 illustrates a top view of an exemplary
`closed-loop sensor;
`
`FIG.34 illustrates a side view ofthe cross-section
`[0060]
`of the exemplary closed-loop sensor of FIG. 33;
`
`(0061] FIG. 35 illustrates the lightning-bolt-shaped elec-
`trodes of an exemplary closed-loop sensor having an interior
`opening and four exterior regions;
`
`[0062] FIG. 36 illustrates a plurality of closed-loop sen-
`sors fo vary the settings of audio controls;
`
`[0063] FIG. 37 illustrates two sets of two closed-loop
`sensors formed concentrically about a single origin for an
`audio system;
`
`FIG.38 illustrates four closed-loop sensors for an
`[0064]
`audio system formed in concentric circles about a single
`origin;
`
`[0065] FIG. 39 is a flow chart of a method of calculating
`a position of an object on a closed-loop sensor by perform-
`ing a quadratic fitting algorithm;
`
`[0045] FIG. 18 illustrates a cross-sectional view of
`V-shaped depressed grooves that define the path on a closed-
`loop sensor;
`
`[0066] FIG. 40 is a graph of the second quadraticfitting
`step in whichthe three capacitance measurements from the
`three adjacent electrodes are fitted to an inverted parabola;
`
`[0046] FIG. 19 illustrates a cross-sectional view of a
`raised projection that defines the path on a closed-loop
`sensor;
`
`[0067] FIG. 41 is a flow chart of a methodof calculating
`a position of an object on a closed-loop sensor by perform-
`ing a centroid interpolation algorithm;
`
`21
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`21
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`

`

`US 2004/0252109 Al
`
`Dec. 16, 2004
`
`[0068] FIG. 42 is a flow chart of a methodofcalculating
`a position of an object on a closed-loop sensor by perform-
`ing a trigonometric weighting algorithm;
`
`[0069] FIG. 43 is a flow chart of a methodofcalculating
`a position of an object on a closed-loop sensor by perform-
`ing a quasi-trigonometric weighting algorithm;
`
`[0070] FIG. 44 is a flow chart of a method of determining
`relative motion of an object on a closed-loop sensor; and
`
`(0071] FIG. 45 is a flow chart of a method of using the
`angular component to determine the sign of the traversal
`along the closed-loop path.
`
`DETAILED DESCRIPTION
`
`[0072] Those of ordinary skill in the art will realize that
`the following description of the present invention is illus-
`trative only and not in any way limiting. Other embodiments
`of the present invention will readily suggest themselves to
`such skilled persons.
`
`[0073] An objectposition detector is disclosed comprising
`a touch (or proximity) sensor (or touch pad or touch screen
`or tablet), such as a capacitive, resistive, or inductive sensor
`designed to sense motions along a substantially closed loop,
`and referred to herein as a closed-loop sensor. This closed-
`loop sensor can be used to enhance the user interface of an
`information-processing device. A loop area on a closed-loop
`sensor can be defined by a tactile guide. Preferably,
`the
`closed-loop sensor is defined by a physical constraint. The
`position of an input object (or finger or pointer or pen or
`stylus or implement) is measured along this loop. When the
`input object moves along this loop, a signal is generated that
`causes an action at the host device. For example, when the
`input object moves in the clockwise direction along this
`loop, a signal is generated that can cause the data, menu
`option, three dimensional model, or value of a setting to
`traverse in a particular direction; and when the input object
`moves in the counter-clockwise direction, a signal is gen-
`erated that can cause traversal in an opposite direction. This
`looping motion of the input object within the loop area need
`only be partially along the loop, or if the looping motion
`completes one or more loops, be approximate and notional.
`A strict loop can imply that the input object would eventu-
`ally return to exactly the same position on the sensor at some
`point. However, the sensor may report the input object's
`position with greater accuracy than the input object can
`actually repeatably indicate a position. Hence, enabling the
`sensor to accept a close approximation to a loop as a
`completed loop is desirable.
`
`[0074] Aclosed-loop sensor can be physically designed or
`electrically laid out in such a way as to naturally report in
`only one coordinate. This single coordinate design, which
`will be referred to as “one-dimensional” within this docu-
`
`the closed-loop sensor
`in that
`is one-dimensional
`ment,
`inherently outputs information only in one variable;
`the
`closed-loop sensor itself may physically span two or more
`dimensions. For example, a closed-loop sensor can consist
`ofa loop of capacitive electrodes arranged along the perim-
`eter of a closed loop of any shape herein described. The
`absolute position of the input object on a one-dimensional
`closed-loop sensor can be reported in a single coordinate,
`such as an angular (0) coordinate, and the relative positions
`(or motions) of the input object can be reported in the same
`(such as angular) units as well.
`
`[0075] The operation ofthe present invention with a host
`device is illustrated in the block diagram of FIG. 1. Asignal
`is generated at the closed-loop sensor LO andis then decoded
`by the closed-loop path decoder 12. A message is generated
`by the message generator 14 and the messageIs transmitted
`to the host device 16, The host device 16 then interprets the
`message and causes the appropriate action on a display (not
`shown).
`
`[0076] The closed-loop sensor (or several closed-loop
`sensors) can be disposed in any location that is convenient
`for its use with a host device, and optional other input
`devices, A host system can be a computer, a laptop or
`handheld computer, a keyboard, a pointing device, an input
`device, a game device, an audio or video system, a thermo-
`stat, a knob or dial, a telephone, a cellular telephone, or any
`other similar device. For example, the closed-loop sensor
`can be positioned on a laptop near the keyboard asillustrated
`in FIG. 2. The base 20 of the laptop is illustrated having a
`keyboard 22, a touch pad (or
`touch screen) 24, and a
`closed-loop sensor 26. Alternative positions include posi-
`tioning the closed-loop sensor on or connecting it
`to a
`conventional computer or keyboard. FIG, 3 illustrates the
`closed-loop sensor 26 disposed on a conventional pointing
`device 28. Conventional pointing device 28 may have other
`features, such asleft click or right click buttons, which are
`not shown.
`
`[0077] The closed-loop sensor of the present invention can
`also be implemented as a stand-alone device, or as a separate
`device to be used with another pointing input device such as
`a touch pad or a pointing stick. The closed-loop sensor of the
`present invention can either use its own resources, such as
`a processor and sensors, or share its resources with another
`device. The closed-loop sensor can be a capacitive, resistive,
`or inductive touch or proximity (pen or stylus) sensor. A
`capacitive sensor is preferred, and is illustrated herein.
`
`[0078] The closed-loop sensor can be implemented as a
`stand-alone sensor, which can then be used as a replacement
`for one or more knobs, sliders, or switches on any piece of
`electronic equipment. In some cases, it might be desirable to
`provide visual feedback indicating the “current” setting of
`the virtual knob, such as a ring of light emitting diodes
`(LEDs) surrounding the closed-loop region. An Etch-a-
`Sketch™type ofelectronic toy can be implemented using a
`single position detector with twoclosed-loop sensors or two
`position detectors with one closed-loop sensor each. Many
`other toys and consumer appliances currently have knobs
`used in similar ways that can benefit from the present
`invention.
`
`[0079] The closed-loop sensor can have electrodes (or
`sensor pads) that are of various shapes and designs (e.g., a
`simple wedge or pie-shape, a lightning-bolt or zigzag
`design, triangles, outwardspirals, or the like) configured in
`a closed-loop path. A closed-loop sensor 30 having wedge-
`shaped electrodes is illustrated in FIG. 4, while a closed-
`loop sensor 34 having lightning-bolt-shaped electrodes is
`illustrated in FIG. 5. The sensor pattern can be designed so
`that it can have continuous interpolation between the elec-
`trodes. The sensor pattern can also be designed so that the
`electrodes interleave between each other to help spread the
`user’s input signal over several electrodes.
`
`[0080] FIG. 4 illustrates the wedge- (or pie-) shaped
`electrodes in a closed-loop capacitive sensor 30. When an
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`US 2004/0252109 Al
`
`Dec. 16, 2004
`
`input object (or finger or pointer or stylus or pen or imple-
`ment) is over first electrode 31, only the first electrode 31
`senses the largest change in capacitance. As the input object
`moves clockwise toward electrodes 32 and 33, the signal
`registered by first electrode 31 gradually decreases as the
`signal registered by the second electrode 32 increases; as the
`input object continues to move further clockwise toward
`third electrode 33, the first electrode 31 signal drops off and
`the third electrode 33 starts picking up the input object, and
`so on. By processing the electrode signals in largely the
`same way as for a standard linear sensor, and taking into
`account
`that
`there is no true beginning or end to the
`closed-loop sensor, the object position detector having the
`wedge sensor can interpolate the input object’s position
`accurately.
`(0081] FIG. 5 illustrates the lightning-bolt-shaped elec-
`trodes in a closed-loop sensor 34. The lightning-bolt design
`helps spread out the signal associated with an input object
`across many electrodes by interleaving adjacent electrodes.
`The signals on a closed-loop sensor with lightning-bolt
`shaped electrodes are spread out in such a way that the
`electrode closest to the actual position of the input object has
`the largest signal, the nearby electrodes have the next largest
`signal, and the farther electrodes have small or negligible
`signals. However, comparing a lighting-bolt sensor with a
`wedge sensor with a similar size and number of electrodes,
`an input object on the lightning-bolt sensor will typically
`couple to more electrodes than in the wedge sensor. This
`means that the lighting-bolt sensor will have more informa-
`tion about the input object’s position than a wedge sensor,
`and this effect helps increase sensor resolution and accuracy
`in sensing the input object’s position. For best results, the
`electrodes of the lightning bolt sensor needto be sufficiently
`jagged in shape such that the input object on the sensor will
`always cover more than one electrode. The interleaving
`nature of this electrode design means that the spacing from
`one electrode to the next can be larger than in the wedge
`sensor while still providing similar resolution and accuracy.
`The spacing from one electrode to the next with such an
`interdigitated electrode design may even be considerably
`larger than the expected input object.
`[0082] Another exampleis a closed-loop sensor 35 having
`triangle-shaped electrodes, as illustrated in FIG. 6. In this
`case, the odd-numbered triangle-shaped electrodes (e.g. 37,
`39) are wider toward the outer edge ofthe closed-loop area
`and narrower toward the inner edge of the closed-loop area,
`while the even-numbered triangle-shaped electrodes (e.g.
`36, 38) have the opposite positioning. To compute the input
`object’s angular position around the clo