Multi-touch system and method for emulating modifier keys via fingertip chords

- Apple

A multi-touch system is disclosed that recognizes simultaneous touchdown of four fingers on, above, or below the home row of keys as a modifier chord and applies modifiers such as Shift, Ctrl, or Alt to subsequent touch activity until none of the chord fingertips remain touching. Touches by the thumb of the modifier chord hand that occur before any modifiable typing or clicking activity cause the modifier chord to be canceled and reinterpreted as hand resting. The Shift modifier may be released temporarily during thumb keypresses that are intermixed with typing of capitalized characters. Distributing the modifier chord touches across different zones or key rows selects multiple modifiers. In an alternative embodiment, different modifiers can be selected with different arrangements of the fingers relative to one another within the chord, irrespective of absolute hand alignment with the touch surface.

Skip to: Description  ·  Claims  ·  References Cited  · Patent History  ·  Patent History

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to multi-touch input systems and methods, and more particularly to a mixture of chord keying, gesture recognition and touch typing techniques.

2. The Related Art

The primary use of chords, or simultaneous finger presses, within the data entry art has been in chord keying schemes that map each letter of the alphabet or even shorthand word parts to a different finger combination. This allows chord keyboards to have a reduced number of keys, often limited to a home row of keys. This in turn reduces finger travel and potentially speeds typing. Some schemes, like U.S. Pat. No. 5,281,966 to Walsh, adopt a mapping that is sensibly organized so as to be easy to learn and remember, while others, such as U.S. Pat. No. 5,642,108 to Gopher et al., emphasize long-term keying performance by assigning the most frequently entered letters of the alphabet to those finger combinations that are quickest and easiest to perform. In U.S. Pat. No. 5,808,567, McClound discloses a scheme for communicating with three-finger chords. In this system, a touch of the index finger on one of the nine regions of a small selector pad can be modified by thumb and/or middle finger presses on switch pads adjacent to the selector pad.

The recent development of multiple-touch sensitive surfaces that lack the restrictions of distinct mechanical keys warrants a reexamination of chording schemes. Direct adaptation of the chord keying schemes cited above to a multi-touch surface certainly seems feasible, but may not be desirable. U.S. Pat. No. 5,825,352 to Bisset et al. describes a touchpad with row and column electrodes that produces pointing in response to single finger motion and dragging in response to two finger motion. U.S. Pat. No. 6,107,997, Ure utilizes the touch sensor array of U.S. Pat. No. 5,194,862 and interprets single finger motions as pointing while interpreting various placements of a 2-finger chord on a grid as key entry. In U.S. application Ser. No. 09/236,513, however, Westerman and Elias take yet another approach, interpreting asynchronous touches on a multi-touch surface (MTS) as conventional single-finger typing while interpreting motions initiated by chords as pointing, clicking, and other gesture commands. We prefer this approach for the following reasons: learning a few new chords for graphical manipulation is much easier than learning a slew of new chords for typing the whole alphabet, and graphical manipulation seems a better use of chords in today's graphics intensive computing environment. In dictation situations where greater text entry speeds are needed than can be achieved with non-chordic keying, adopting a continuous speech recognition system for text entry is becoming more practical than learning a chord keying technique.

Non-chordic touch typing on surfaces that provide limited tactile feedback presents its own difficulties. If the typist is not careful, the hands or individual fingers tend to drift out of alignment with the key layout, or more particularly with the home row of keys where hands normally rest. Reaching for punctuation and modifier keys located on the periphery of QWERTY computer keyboard layouts exacerbates this drift. Though the Shift modifier key is not particularly far from the home row keys, the direction of pinky motion needed to reach Shift strongly pulls the other fingertips off their alignment with home row. Since the Shift modifier key must be reached so frequently to capitalize words, even typists using mechanical keyboards have long complained about the awkward pinky twist and ulnar deviation at the wrist necessary to hold it down. Accurately, hitting the Shift keys becomes, if anything, more awkward on a relatively smooth surface that does not give like a mechanical key.

In the related ergonomic and chord keyboard art exemplified by FIG. 2 modifier keys such as Shift, Ctrl, and Alt are often allocated to the thumbs (e.g. U.S. Pat. No. 5,642,108 to Gophert et al. and U.S. Pat. No. 5,689,253 to Hargreaves et al.) or to palm presses, as in U.S. Pat. No. 5,017,030 to Crews. However, for a multi-touch surface, reaching the thumb for modifier keys poses the same drift exacerbation problems as reaching by the pinky, and palm touches should be ignored to encourage hand resting. Thus there exists a need in the multi-touch and chord keying art for alternative methods to activate modifier keys without drawing any fingers away from the row.

BRIEF SUMMARY OF THE INVENTION

In its primary aspect, this invention introduces four-fingertip modifier chords to eliminate the hand twist and reach traditionally required to activate modifier keys. Simultaneously dropping the four long fingertips of a hand into a modifier zone on or near the home row keys applies the Shift modifier to subsequent typing or pointing input so long as any finger from the modifier chord remains touching the surface. Typically, then, the modifier will apply to activity by the opposite hand, but the present invention also lets a hand modify its own typing, thereby allowing capitalization of whole words, if at least one of its modifier chord fingertips remains touching as others lift to strike nearby keys. The four-fingertips (excluding the thumb) chord is preferred for this role because it is the easiest to drop and hold on the surface besides the five-finger chord, which must be reserved for hand resting.

Since the four-fingertip chord is also preferred for window scrolling, and since it is often a prelude to dropping the thumb into the full five-finger hand resting chord, the present invention takes special precautions to prevent accidental modifier activation. The modifier press signal is not sent to the host computer immediately upon detection of the modifier chord touchdown. The modifier press will only be sent, commiting the modifier, upon detection of modifiable input activity by other than the thumb of the modifying hand. Modifiable input activity can include any user action that produces a keypress, pointing, dragging, clicking or other command for the host computer, but does not typically include resting touches that cause no signals to be output. Any touch by the modifying hand's thumb detected before commit will immediately cancel the modifier chord, effectively turning it into a hand resting chord. Such thumb touches after the modifier press or commit need not permanently cancel the modifier. However, if these thumb touches represent editing keys such as Space or BackSpace keypresses, the Shift modifier signal may release temporarily while the thumb key is transmitted since the typist is most likely just erasing or putting a normal space between two capitalized words.

Restricting the Shift modifier chord to a zone along home row encourages typists to return their hands to the home typing position. Furthermore, this allows a Ctrl modifier zone to be established along the row of keys above home row, an easy stretch from home row. A third modifier zone can be established along the row of keys below home row for rarer modifiers such as Alt, Windows, Open Apple, or Meta. Even a fourth modifier zone is possible approximately two key rows below home row. Note that all of these modifier zones can be reached through straight flexion or extension of the fingers from their home row position-absolutely no twisting or rotation of the wrist or fingers is necessary.

According to the present invention, multiple modifiers are activated by the same hand simultaneously when the fingertips of the modifier chord are clearly distributed into different modifier zones. To compensate for the natural arch in a row of fingertips, the vertical offset of each finger is measured relative to the home row key the finger normally rests upon. Accidental activation of a multiple zones is prevented by checking for a minimum interval between the vertical offsets of fingertips in different zones. If this condition is not met, the average of the vertical fingertip offsets is used to choose a single modifier zone. Distributing the fingertips into different zones does imply some finger twisting, but does not cause as much hand drift as reaching for multiple modifier keys on the periphery of the key layout.

In an alternative embodiment of this invention, different modifiers can be activated in a manner independent of any zones or the overall hand position on the surface. Rather, they are distinguished by different horizontal and vertical separations between the four fingertips performing the chord. Shift, for example, might be activated by the normal relaxed placement of four fingertips in a row with about 2 cm (¾″) separating the fingertip centers. Ctrl would then be activated by placing the fingertips stretched along the row with an average 3 cm (1⅛″) separation between them. A third modifier could be activated by splitting the fingertips vertically into two rows a couple cm apart. This aspect of the invention is most useful for non-typing situations where hand motions are not focused around a default position along home row. With this aspect, a hand can, for instance, apply different modifiers to mouse clicking activity on the opposite hand without having to reposition itself within certain modifier zones.

A primary objective of the present invention is to provide an apparatus capable of detecting four-fingertip modifier chords that obviate the awkward pinky or thumb reaches previously needed to strike and hold modifier keys.

Another objective of this invention is to prevent spurious modifier chord activation when the user is slowly relaxing into a hand resting chord, but does not initially have the thumb on the surface.

A further objective of this invention is to allow use of the Shift modifier chord for capitalization across words without applying the Shift modifier to intervening Space or BackSpace key activations by thumbs.

Yet another objective of this invention is to establish different modifier zones across, above, and below the home row of keys that can be utilized to apply different modifiers.

A further objective of this invention is to support simultaneous activation of multiple modifiers with the same hand when the fingertips of the modifier chord are clearly distributed among different modifier zones.

Another objective of this invention is to support selection of different modifiers from the relative arrangement of fingertips within a modifier chord rather than their placement within any particular zone on the surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block level diagram of a multi-touch system with typing, chord motion, and modifier chord recognition according to a preferred embodiment of the present invention.

FIG. 2 is a diagram of a split QWERTY key layout with prior art modifier keys that are struck by the pinky or thumb.

FIG. 3 is a diagram of a split QWERTY key layout with a different chord modifier zone overlapping each row of keys according to a preferred embodiment of the present invention.

FIG. 4 is a data flow data diagram showing the relation to the processes and data that the present invention uses to detect and apply modifier chords in its preferred embodiment.

FIG. 5 illustrates the contents of the touch data structure used to store touch location, identity and timing and, when formed into a chain, represent a sequence of touches.

FIG. 6 illustrates the contents of the data structure used to keep track of a modifier chord's state through its life cycle of being canceled or applicable and eventually lifted.

FIG. 7 illustrates the configuration parameters used in the preferred embodiment to represent a single modifier zone.

FIG. 8 is a flowchart of the process that detects new modifier chords.

FIG. 9 is a flowchart detailing computation of fingertip vertical offsets from the default fingertip locations.

FIG. 10 is a flowchart of the preferred embodiment of the process that detects which modifier zone(s) a chord is selecting.

FIG. 11 contains touching timing diagrams showing preferred system responses to thumb touches during modifier chord performance.

FIG. 12 contains touch timing diagrams that demonstrate sustain of a modifier chord throughout typing touches by the modifier chord fingertips.

FIG. 13 contains touch timing diagrams for cases in which a modifier chord should be allowed to apply to touch activity that actually occurs slightly before its touchdown or after its liftoff.

FIG. 14 is a flowchart of the process that detects modifier chord cancellation and/or liftoff according to the present invention.

FIG. 15 is a flowchart of the process that searches for modifier chords or keys applicable to modifiable input activity at a given time.

FIG. 16 shows several distinct fingertip arrangements that can be configured to select and apply different modifiers in an alternative to modifier zones.

FIG. 17 illustrates alternative configuration parameters that can encode a template for a recognizable arrangement of fingers within a modifier chord.

FIG. 18 is a flowchart of the alternative modifier selection process that finds the fingertip arrangement template that most closely matches the fingertip arrangement within a performed chord irrespective of absolute hand position on the surface.

DETAILED DESCRIPTION OF THE INVENTION

In the preferred embodiment, the typing recognition methods of this invention are utilized within a multi-touch system like that shown in FIG. 1. The sensor scanning hardware 6 detects touches by fingers 2 on the touch surface 4. The proximity image formation 8 and contact tracking and identification 10 modules determine the touch timing and surface coordinates and report these to the typing recognizer 12. The typing recognizer decides which keys the user intended to press and tells the host communications interface 16 to send those keys to the host computer 18. The chord motion recognizer module 14 that interprets lateral sliding of multiple fingers as pointing or gesture input and effectively disables the typing recognizer for such touches. The synchronization detector 13 searches for simultaneous presses or releases of multiple fingers, thereby aiding in detection of chord slides, chord taps, resting hands, and, for the purposes of this invention, modifier chords. Prior art embodiments of all modules in FIG. 1 except the MODCHORD subdivisions 15 are described in related U.S. pat. app. Ser. No. 09/236,513 by Westerman and Elias. That application is incorporated herein by reference in its entirety. It discloses techniques for detection of chord taps and generation of single commands or button clicks therefrom. It also discloses methods to detect and apply conventional modifier key touches. However, unlike the present invention, that application does not teach recognition of modifier chords nor associated techniques for selecting modifier types according to the zone a chord falls within or the template arrangement best matching its finger arrangement, canceling the chord in response to thumb resting, committing a modifier chord upon reception of subsequent modifiable input activity, nor sustain of modifier signals through typing by both hands until no fingers from the modifier chord remain touching. The detection 56, cancellation 60, and application 62 processes embodying the improvements of the present invention are widely distributed across the typing recognizer 12, synchronization detector 13, and chord motion recognizer 14 modules so as to efficiently apply modifier chords to the other input activities that these modules recognize. Thus these modifier recognition processes are collectively represented in FIG. 1 by the MODCHORD subdivision 15 of each module. The exact relation of the modifier chord recognition processes to each larger recognition module will be made apparent from the following detailed description. U.S. pat. app. Ser. No. 09/681,146 by Westerman further describes an improved typing recognizer 12 that compares touch geometry to key sequence candidate geometry, but its improvements do not bear directly on modifier chord recognition.

Those skilled in the art will recognize that the modifier chord recognition method disclosed herein could be utilized with any sensing device that accurately reports the lateral position of multiple fingertips on a surface. Likewise, the modifier chord recognition software need not reside within the sensing device. It could just as easily execute within the host computer system, or the host computer system and sensing device might be combined such that the same microprocessor executes finger tracking, modifier chord recognition, and user application software. Those with ordinary skill in the art will also be aware that some keyboard interfacing protocols use edge-signaling of key activation state while others use level-signaling. For instance, keyboards with the legacy PS/2 interface for IBM-compatible PCs will transmit a press keycode only upon initial activation of a modifier keyswitch and will send a corresponding release keycode immediately after the finger lifts off the switch. Thus the press/release keycodes are only transmitted at edges or transitions in the state of the keyswitch. Keyboards communicating via the more recent USB (Universal Serial Bus) protocol use level-signaling: as long as a keyswitch is depressed, the keyboard regularly and repeatedly sends the corresponding keycode to the host computer. There are no distinct press and release keycodes. This disclosure will use the edge-signaling, press/release terminology throughout to describe transmission of modifiers to the host computer 18, but it will be apparent to those of ordinary skill in the art how any edge-signaling implementation of the host communications interface 16 can be converted to level-signaling and remain well within the scope of this invention.

The key layout illustrated in FIG. 2 exemplifies prior art placement of modifier keys 20, 21, and 22 such that they can be reached by the thumb or pinky fingers. This diagram shows a QWERTY layout split into left 23 and right 24 halves such that Ctrl and Alt modifier keys 22 can be placed between the split halves within easy reach of either thumb. Non-split layouts are more likely to place Ctrl and Alt modifier keys 21 on the bottom row of the layout where they are most likely to be operated by the pinkies. Whether split or not, most layouts keep the Shift modifier keys 20 diagonally below the home row key (‘A’ or ‘;’) that the pinky normally rests upon. Though these Shift keys 20 are not that far from home row, the pinky motion needed to reach and hold them down is particularly awkward.

In contrast to prior art FIG. 2, FIG. 3 shows the chord modifier zones 30-34 and 35-37 of the present invention as different hatches ranging across each row of the key layout. In an actual product, the different modifier zones would be indicated on the touch surface by different background colors rather than different hatches. According to the preferred embodiment of the present invention, simultaneous touchdown of four fingertips within one of these zones will cause subsequent touch activity to be modified just as if a modifier key was being held as long as the modifier chord is not fully lifted or canceled by an improper thumb touch. Notice that a hand resting on the home row ‘ASDF’ or ‘JKL;’ keys can activate any of its modifier zones by pure finger flexion or extension, eliminating the awkward twists needed to reach conventional modifier keys. Notice also that the modifier zones are not horizontally restricted to the ‘ASDF’ or ‘JKL;’ key columns, so the typist need not worry about horizontal hand alignment when performing a modifier chord. The key layout improved with modifier zones may retain the conventional Shift modifier keys 20 near the pinky for the convenience of novices who have not yet learned to perform modifier chords, but experience with the invention has shown that typists rarely use these conventional modifier keys once they have learned the more convenient modifier chords. Since capitalization is needed so frequently, the modifier zones 31 and 36 along the left and right home row of keys are preferably assigned the Left Shift and Right Shift modifiers. The modifier zones 30 and 35 above home row are preferably assigned the Left Ctrl and Right Ctrl modifiers, and the zones 32 and 37 directly below home row are preferably assigned the Left Alt and Right Alt modifiers. Modifier zones 33 and 38 can be assigned any remaining modifiers such as Meta, Diamond, Windows, or Open apple supported by the host computer 18's particular operating system. Those skilled in the alternative key layout arts will realize that modifier zones can be established just as easily over Dvorak, non-split, or non-English key layouts. Also, those skilled in the foreign keyboard arts will realize that the modifier zones could alternatively be assigned to Asian language modifiers like Kana or Kanji and remain well within the scope of this invention.

In the preferred embodiment of the present invention, modifier chord recognition is split into three processes as shown in FIG. 4. Process 56, detailed in FIG. 8, detects new modifier chords by monitoring the incoming touch sequence 50 for touchdowns by the four fingertips of one hand that are simultaneous and also lie within one of the zones or arrangements specified by the configuration data 54. This process only needs to execute each time a new finger touch is detected and appended to the touch sequence, not for image frames from the sensor scanner 6 that contain no new surface contacts. The incoming touch sequence 50 consists of a chain of touch data structures 80 (detailed in FIG. 5) ordered by touchdown times 85. The configuration data structures 100 and 520 that store the modifier zones or arrangements 54 are detailed in FIG. 7 and FIG. 17. If it detects a new modifier chord, process 56 will allocate a corresponding modifier state data structure 90 (detailed in FIG. 6 ) and appended it to the modifier chord state chain 58. The liftoff/cancellation detection process 60 (detailed in FIG. 14 ) checks each new image frame or sensor array scan for absence of all four fingertips or presence of the thumb from any hand with a modifier chord pending in the state chain 58. Upon detection of one of these conditions, the liftoff/cancellation process 60 uses feedback path 68 into the modifier state chain 58 to record either the chord liftoff time 94 or chord cancellation 96. It may also send corresponding modifier release signals to the host computer 18 through the host communication interface 16. The third process 62 searches the modifier state chain 58 for uncancelled modifier chords roughly coincident with modifiable input activity. If this process finds any applicable modifier chords whose press signals have not already been sent, it will cause the host computer interface 16 to send their modifier press signals to the host computer 18. This search process 62 is typically called by the typing recognizer 12, synchronization detector 13, or chord motion recognizer 14 with the timestamp 64 of the modifiable input activity right before such activity itself is transmitted through the host communication interface 16.

FIG. 5 lists basic parameters needed for each touch data structure 80 to support detection of new modifier chords 56. A ring or chain of such data structures ordered by touchdown time 85 represents a touch sequence by one or more fingers. Since palm touches are to be ignored by all recognition processes, they can be left out of the touch sequence 50. Each touch data structure 80 must contain the touch's x and y surface coordinates 82 as reported by the touch sensors 6. These should estimate the center of the touch, which for proximity or pressure sensors is typically computed as the centroid of fingertip flesh contacting the surface. The y offset from default finger location 84 will be computed in FIG. 9 to improve the accuracy of modifier zone selections. To help determine whether a touch sequence represents the four fingertips of a modifier chord, each touch data structure should have a copy of the hand and finger identity 84 estimated for the touch by the contact tracking and identification module 10. To help detect synchronization of multiple touches, the touch data should also include the finger touchdown time 85, also reported by the contact tracking and identification module 10. While the touch liftoff time 86 is a useful indicator of individual modifier key release, the modifier chord liftoff time 94 is not derived from the individual liftoff times 86 of the touches originally forming the chord. This is because in its preferred embodiment the present invention beneficially allows individual fingertips of a modifier chord to lift temporarily and touch again to type while other modifier chord fingertips remain touching, as is shown in FIG. 12. These temporary finger lifts will establish the touch liftoff times 86 for the original touches forming the chord but may not be indicative of final chord liftoff since the temporarily lifted fingers may touch again to sustain the chord while other modifier fingertips lift to type, and so on.

FIG. 6 lists the parameters that keep track of a modifier chord's state 90 once it is initially detected by process 56. The modifier type bits 91 encodes which modifiers, e.g. Shift, Ctrl, or Alt, the chord's fingertip placement has selected. The contents of these bits will be determined by either the modifier zone selection process of FIG. 10 or the fingertip arrangement selection process of FIG. 18. The hand field 92 indicates which hand performed the modifier chord. The chord touchdown time 93 is set by the new chord detection process 56 as the minimum of the touchdown times 85 of the original four fingertip touches firming the chord. As discussed previously, the chord liftoff time 94 should not be computed as the maximum of the original touch liftoff times 86. Instead, the liftoff and cancellation check process 60, FIG. 14, will set the chord liftoff time 94 as the first time after chord detection that none of the four fingertips from the chord are found to be touching the surface. The canceled flag 96 is set by the liftoff and cancellation check process 60 if the chord fingertips slide substantially or a thumb from the chord's hand touches before the chord as committed. When set, this flag causes the applicable modifier search process 62 to ignore the modifier chord. The committed flag 97 is set once a modifier chord is actually applied by the applicable modifier search process 62 to outgoing typing or clicking activity. Once set, this flag prevents the chord from being canceled except when fully lifted.

FIG. 7 shows the data structure 100 and parameters used to configure each modifier zone. Here, the modifier type bitmask 102 is a set of flags indicating which of the Shift, Ctrl, Alt or other modifiers are assigned to the zone. Note that this bitmask implementation allows multiple modifiers, such as Shift Ctrl, to be assigned to the same zone if the user so desires. The hand field 104 can restrict the zone to the left 23 or right 24 half of the key layout, but no other horizontal alignment restriction is necessary. The min 106 and the max 108 Y offset from home row determine the vertical range of the modifier zone. Note that no extra configuration parameters are necessary to arch the zones along each row, should the key rows be so arched, because the zone selection process of FIG. 10 will compare these Y offsets with each fingertip's vertical offset relative to the position of the home row key the finger normally rests upon, also know as the fingertip's default position. Thus the modifier zone will automatically arch to match any arch in the home row key locations.

The new modifier chord detection process is shown in FIG. 8. This process begins whenever a new finger touch is detected by the contact tracking and identification module 10. Step 150 increments the latest touch index n and stores the touch's parameters 80 at the n th location of the touch sequence array T[ ]. Steps 152, 154, and 156 scan backward m touches in the touch sequence trying to find the largest synchronized subsequence that includes the new touch T[n]. Decision diamond 154 judges synchronization by testing whether the m th previous touch T[n−m] contacted the surface within a synchronization interval of about 60 milliseconds of the new touch T[n]. Note that the typing recognizer 12 should not generate signals to the host corresponding to an individual touch over a key until sufficient time has passed without subsequent touches on the same hand that this synchronization detection loop can be certain that the touch is not synchronized with later touches. Thus the typing recognizer 12 must delay key output about 60 ms from finger touchdown or be prepared to erase or undo keys from touches later found to be part of a chord. Once decision diamond 154 finds a previous touch too old to be synchronized with T[n], it passes on the largest synchronized subsequence as T[n−m+1] . . . T[n].

Decision diamond 158 then examines the finger and hand identity 84 of each synchronized touch looking for a combination of identifies from one hand that matches any combination allowed for modifier chords. In the preferred embodiment, only the 4 fingertip combination, index, middle, ring and pinky, excluding the thumb, is used for modifier chords. To prevent duplicate detection of the same modifier chord, decision diamond 158 must require the newest touch T[n] to be one of the modifier chord fingertips. Otherwise, any synchronized touches intervening from the hand opposite a modifier chord combination do not affect the modifier chord, but the modifier chord may eventually apply its modifiers to them as in touch 370 of FIG. 13. If the synchronized subsequence does not contain a modifier chord combination from either hand, the process returns 160 until the next new touch warrants a renewed detection attempt.

Assuming a modifier chord combination from one hand is found within the synchronized subsequence, block 162 forms a touch array MT[ ] indexed by finger identity containing only the modifier chord touches. As further described in FIG. 9, block 162 also computes each touch's vertical offset from its corresponding home row key or default location. Block 164, further described in FIG. 10, checks whether the chord has been performed within any of the established modifier zones. In an alternative embodiment, block 164 may check the arrangement of fingertips within the chord as further described in FIG. 18. Decision diamond 170 ends new modifier detection through step 168 if the chord matches none of the established zones or arrangements. Otherwise, step 172 allocates a new modifier state 90, setting the modifier type 91 according to that of the selected zones or arrangement, setting the modifier hand 92 to be detected chord's hand identity, and setting the chord touchdown time 93 as the minimum of the touchdown times 85 of the synchronized touches forming the chord, and setting the chord liftoff time 94 to 0 pending full liftoff detection. Step 172 also appends this new modifier state to the state chain 58 that may already contain state from other chord or key modifiers being held by the opposite hand. New modifier detection returns at step 176, and responsibility for canceling the modifier chord or applying it to modifiable input activity passes to processes 60 and 62.

FIG. 9 shows the details of vertical offset computation block 162. Step 200 starts the sync index s at the oldest synchronized touch and loops 210 through the synchronized subsequence. Decision diamond 204 separates out the modifier chord touches from any opposite hand touches. For the convenience of the modifier zone or arrangement matching process 164, step 206 stores each modifier chord touch into the touch array MT[ ] in order of their finger identity 84. Step 208 computes each modifier touch's vertical offset from the default or resting location of its corresponding finger. For key layouts such as 23 and 24 with an arch across the home row keys, these default locations should be the locations of the ‘ASDF’ and ‘JKL;’ keys. These vertical offsets help the modifier zone matching process 164 efficiently compensate for the natural arch across the fingertips. Decision diamond 202 breaks the loop and returns through 212 once the whole synchronized subsequence has been processed.

FIG. 10 discloses the preferred embodiment of block 164, a search for modifier zones 100 that the modifier chord fingertips lie within. The array Z[ ] of configured zones is assumed to contain only zones for the given modifier chord's hand, and these zones are assumed to be ordered within the array from farthest below home row to farthest above. In this embodiment, the loop of steps 250-276 will attempt to accumulate modifier types from each zone that any of the modifier chord fingertips lies within. If, however, decision diamond 262 finds that the fingertips are not clearly spaced across zones, i.e. if two or more fingertips are vertically bunched together yet straddling the border between two zones, it will direct the loop of steps 280-288 to find the single zone that the average of the fingertip offsets falls within. Step 250 clears selected_mods, the variable whose bits will accumulate the selected modifier types. Step 252 clears the modifier zone index i. Step 254 initializes the max vertical offset for fingertips found in the i th zone, Z[i].found_ymax, to the zone's minimum vertical boundary Z[i].range_ymin. Step 256 initialized the modifier fingertip index f to 2, representing the index finger. Decision diamond 260 checks whether touch MT[f]'s vertical offset from default is within zone Z[i]'s boundaries. If not, decision diamond 270 checks whether all fingertip touches including the pinky have been examined, and if not step 272 advances the fingertip index. If touch MT[f] is within Z[i]'s vertical range, decision diamond 262 checks whether it is vertically separated by at least zone_safety_sep from any touches already found in the zone below. zone_safety_sep should be set to about 1 cm or ⅜″. If the touch is clearly separated form any in the zone below, step 264 will bump up Z[i].found_ymax as necessary. Step 266 accumulates the modifier types 91 assigned to Z[i] into the selected_mods bits with a bitwise OR operation. Once all fingertips have been checked against the i th zone, decision diamond 274 will check whether all zones have been tested, and if not advance to the next zone through step 276. If the loop 254-276 gets through all zones without decision diamond 262 finding a fingertip separation violation, step 278 will return the accumulated modifier types selected_mods to decision diamond 170 of FIG. 8.

If decision diamond 262 detects an interzone fingertip separation violation, the zone index i and selected_mods are reset at steps 280 and 282. Step 284 computes from MT[ ]the average avg_yoffset of all four fingertips' vertical offsets. Decision diamond 286 checks whether this avg_yoffset is within the range of zone Z[i]. If not, step 290 advances the zone index to the next zone until either decision diamond 292 finds all zones have been exhausted or decision diamond 286 finds a matching zone. Assuming avg_yoffset falls within the vertical range of one of the zones, step 288 assigns selected_mods the modifier type(s) of that zone, and step 278 returns these. Note that step 278 will return zero if the fingertips are not within range of any zone.

Before describing in detail the liftoff/cancelation detection process 60 and the search for applicable modifiers 70, it will be helpful to define their preferred behavior with the diagramed typing examples of FIGS. 11-13. These timing diagrams display the touchdown (falling edge) and liftoff (rising edge) timings for particular fingers 84 from both hands, where LF5 denotes the left pinky, LF1 the left thumb, RF2 the right index finger, and so on. Fingers not shown in an example can be assumed to be lifted throughout. All synchronized chord touches 300 are assumed to fall within a Shift modifier zone. The vertical dotted lines 93 and 94 identify the chord touchdown time and liftoff time, respectively. Keys transmitted to the host by the typing recognizer 12 in response to asynchronous touches are denoted by the key's symbol encircled. The key symbol is only capitalized if the Shift modifier chord applies to it. The slight space drawn between each touchdown and the corresponding key character circle simply indicates that the typing recognizer must wait about 60 ms after each touchdown before sending a keypress to ensure that the touch will not be part of a chord. The left and right ends of SHIFT ellipses 318, 319, 338, 339, 348, 378, and 388 in the MODIFIER 66 row demarcate the modifier press and release signals that should be sent to the host computer. Thus the Shift modifier is being applied through the duration of each ellipse. The bottom two rows of each timing diagram indicate setting of the modifier state canceled flag 96 or committed flag 97 in response to certain touches.

FIG 11A shows typing before, during, and after performance of a left hand Shift chord. The initial ‘a’ key touch 310 clearly precedes modifier chord touchdown 93 and so should not be capitalized. Notice that the Shift modifier is not sent to the host, committing the chord 469, until the ‘J’ touch 311 needs to be sent to the host computer, well after modifier chord touchdown. Committing of modifier chords should be thus delayed until transmission of subsequent modifiable activity (the ‘J’ key touch in this case) to allow for the possibility that the 4 fingertips will begin sliding, suggesting that the typist is actually trying to scroll, or be supplemented with a thumb touch, suggesting the typist is just resting the hand sloppily. This subsequent-touch-activity-dependence of modifier chord committing is unique and novel, as the chord and key taps of the related art commit either on liftoff or sufficient touching time of the tapping fingers themselves, while chord slides for pointing and command gestures commit upon significant lateral motion of the involved fingers. The ‘I’ touch 312 is also capitalized, but the Shift modifier is temporarily released while the BackSpace key touch 302 is sent to the host, and then Shift is pressed again at 319 in time for the ‘U’ key touch 313. Decision channel 463 of FIG. 15 will handle such temporarily release of thumb editing keys such as BackSpace and Space under the assumption that typists usually intend to make quick, unshifted edits but are too lazy to lift and retouch the Shift chord before and after the thumb key activations. The ‘n’ key touch 314 clearly follows modifier chord liftoff, and therefore should not be capitalized.

FIG. 11B demonstrates the desired system behavior when the modifying hand's thumb touches down before typing or clicking activity amongst the other fingers has a chance to commit the modifier chord. As before, the touches 320 and 323 before and after modifier chord performance do not get capitalized. However, the ‘i’ and ‘n’ key touches 321 and 322 concurrent with the modifier chord do not get capitalized either because the thumb touch 302 preceding them causes the modifier chord to be canceled 404. Whether the thumb touch lands properly on and activates the BackSpace key or whether it lifts back off before the ‘i’ and ‘n’ touches is not important. The thumb touch 302 is quite likely the result of sloppy hand resting, and should cancel the modifier chord lest subsequent typing or clicking be shifted unintentionally and have to be undone. Decision diamond 402 of FIG. 14 will implement cancellation due to resting thumb touches.

FIGS. 12A and 12B demonstrate how a modifier chord can be sustained through typing by its fingers on its half of the key layout so that whole words can be capitalized from a single modifier chord touchdown. In FIG. 12A, the ‘K’key touch 330 on the opposite hand quickly commits 469 the modifier chord and the ‘I’ touch 331 follows. To obtain a capitalized ‘D’ and ‘S’, the typist need only lift the middle and ring fingertips of the modifier chord and set them down 332 and 333 on those keys one at a time. The typing recognizer must be configured to generate keys from asynchronous touches without waiting for touch liftoff for this to work well, as at least one of the resumed touches 332 and 333 will need to sustain one of the resumed touches 332 and 333 will need to sustain the modifier chord while the pinky and index of the modifier chord temporarily lift to touch the ‘A’ 335 and ‘T’ 336 keys. Chord liftoff 94 does not register and cause release of the modifier 349 until the first moment when none of the modifier fingertips are touching. The right thumb Space key touch 334 invokes temporary modifier release as in FIG. 11A. FIG. 12B is similar to FIG. 12A except that the modifier chord is performed by the right hand and committed 469 by a temporary liftoff and ‘P’ touchback 340 of one of its own pinky fingertip. Touches 341-343 walk through the other modifier chord fingertips ending with a ‘T’ touch 344 by the opposite hand to spell ‘POINT’. This demonstrates that a modifier chord need not always be committed by the opposite hand, which can be useful in situations where only one hand is available for interaction with the touch surface.

Conventional mechanical keyboards never apply modifier keypresses to keys barely preceding the modifier keypresses or just following the modifier key release. The comparative lack of keyswitch action or stroke for touch surfaces lessens the typist's control over the timing between modifier touch and the touches to be modified. FIGS. 13A and 13B demonstrate cases where it is helpful for the system to tolerate some inaccuracies in the timing between modifier chord touches and modifiable key touches. The same techniques also apply to individual modifier key touches on a surface. In FIG. 13A, the touch 370 actually precedes the modifier chord touchdowns 300 but is roughly synchronous with them. Assuming the modifier chord is detected before the key from touch 370 gets sent to the host, the modifier chord should apply to and capitalize the ‘T’. Such handling of key touches that very slightly precede modifier chord touches is important for typists who get in the habit of simultaneously touching both the modifier chord and the opposite hand's key to be capitalized. The system will implement it through the sync_slack term of decision diamond 456 in FIG. 15. The ‘T’ is capitalized again for touch 371 but not for ‘t’ touch 372, which follows chord liftoff. FIG. 13B shows a brief tap of a modifier chord without any coincident key touches. However, ‘T’ touch 382 does follow shortly after chord liftoff. This suggests the typist was intending to capitalize a single key but, in performing the modifier chord so quickly, synchronized it poorly with the key touch 382 on the opposite hand. It is desirable for the system to compensate by applying the modifier chord in this case even though this means committing 469 and sending the modifier press signal 388 after the chord has actually lifted 94. This is implemented with a non-zero lift_slack in step 464 and decision diamond 466 of FIG. 15.

FIG. 14 details process 60, thumb cancellation and chord liftoff detection. Step 400 denotes that whenever any finger touchdown or liftoff is detected on the surface, this process must be repeated for each modifier chord state 90 in the state chain 58. The combination of decision diamonds 401 and 402 causes the chord to be canceled in step 404 if a thumb touch by the modifier chord's hand is detected before the chord's committed flag gets set. Decision diamond 402 may also decide to cancel a chord if excessive sliding is detected amongst the chord's fingertips. If no such canceling thumb touch is detected, decision diamond 406 checks whether chord liftoff has previously been detected. If not, decision diamond 408 checks the latest sensor image frame 52 for any touches by the modifier chord fingertips. If none are found, step 410 sets the chord liftoff time 94 to the timestamp of the latest sensor image. If liftoff was just detected and decision diamond 412 finds that the modifier types 91 for this modifier state MS are currently pressed for the host, step 414 instructs the host communications interface 16 to send the corresponding modifier release signals. Steps 404 and 410, if executed, thus constitute the feedback path 68 from this process 60 to the modifier state chain 58.

FIG. 15 details the search for applicable modifiers 62 that should always execute just before the typing recognizer 12, synchronization detector 13, or chord motion recognizer 14 transmit any typing, pointing, or clicking signals to the host computer 18. These modules will pass to the search process the modifiable tstamp parameter, set to the current system time for pointing activity but otherwise to the original touchdown time of the key or click chord touches. Step 450 clears the applicable_mods variable, which will accumulate the bitmasks of the types of modifiers found applicable. Step 452 initializes the modifier state reference MS to the most recent modifier state 90 in the chain 58. Decision diamond 456 causes canceled 404 chords to be excluded from the applicable modifier search. At this point the modifier state for a canceled chord can, if memory resources are scarce, be entirely removed from the state chain 58.

Assuming the chord has not been canceled, decision diamond 456 ensures that modifiable_tstamp does not precede the chord touchdown time 93 by more than a sync_slack of about 60 ms. If the chord more or less precedes the modifiable activity, step 460 establishes a 0 ms default lift_slack. If the modifier chord has only been touching briefly and is not yet committed, decision diamond 462 will cause step 464 to establish a lift_slack of about 100-150 ms, allowing for late modifiable touches as in FIG. 13B. If the chord has been touching a few seconds or has already been committed by other key touches, decision diamond 463 checks whether the modifiable activity is a thumb keypress, and if so, should prevent the modifier chord from applying at least if the chord is a Shift modifier. This will also cause temporary Shift modifier release during thumb key transmission as in FIG. 11A and FIG. 12A. Note that this-check is not done for briefly touching chords that have not committed yet so as to allow the typist to perform, for example, a single Shift BackSpace macro command using a modifier chord from the hand opposite the thumb key.

The remaining steps ensure that the modifier chord did not lift substantially before modifiable_tstamp. This is certainly true if the modifier chord is still touching and has not yet been assigned a non-zero liftoff time, as detected by decision diamond 465. If the chord has already lifted, decision diamond 466 will need to compare the chord liftoff time 94 with the modifiable_tstamp less the lift_slack to determine whether the modifiable activity occurred before or within lift_slack milliseconds after chord liftoff. Assuming the modifiable activity is found to be sufficiently coincident with the modifier chord, step 469 will set the modifier state's committed flag 97, and step 468 will accumulate the modifier types selected by the applicable modifier state. Thus step 469 constitutes the main feedback path 70 from the applicable modifier search process 62 to the modifier state chain 58. Decision diamond 471 checks whether any older modifier states that might be applicable are left in the state chain 58, and if so step 470 continues the search on the previous modifier state. Once the entire state chain has been examined, the process returns at step 472 the modifier types from the modifier chords found applicable. The host computer interface 16 will compare these newly applicable modifier types to a bitmask of the modifier types already pressed and send additional modifier press or release signals to the host computer as necessary.

Those skilled in the chord keying art will realize that this chord modifier recognition method could easily be adapted to keyboards with conventional mechanical keyswitches, assuming the keyswitch matrix was wired such that the keyswitch scanner circuitry could reliably distinguish coincident presses of four home row keys forming the chord as well as one other key to be modified. However, such an adaptation would not be terribly advantageous because the effort needed to press four mechanical homerow keyswitches simultaneously is just about as straining as the awkward pinky reach for a conventional Shift key. However, when modifier chords are utilized with a proximity sensing multi-touch surface as in the preferred embodiment, holding the chord requires no effort giving modifier chords significant advantage over the pinky reach for a conventional Shift key.

While modifier zones beneficially allow simultaneous selection of any combination of up to four different modifier types by a single hand, the typist must be careful of hand alignment with respect to the zones to operate them accurately. On surfaces without a home row of keys to encourage hand alignment, or when the user is primarily pointing rather than typing, an alternative, hand-position-independent method to select different types of modifiers is desirable. FIG. 16 shows six sets of chord touches that are distinguishable not by their finger combination or alignment with respect to the key layout, but by the relative arrangement of the four fingertips index 502 through pinky 505 within the chord. The arrangements shown would most likely arise from right hand chord performances; left hand chord performances would produce the mirror image of these arrangements. Each arrangement can be assigned a different modifier type to allow a wide range of modifier selections anywhere on the touch surface. The arrangement of FIG. 16A is most relaxed and is thus preferred for the Shift modifier. The arrangement of FIG. 16B is preferably mapped to Ctrl, FIG. 16E to Alt, FIG. 16C to Ctrl Shift, and the remaining arrangements to any other modifiers useful on a particular host computer. The crosshairs 500 indicate the centroid of each fingertip arrangement and will be used as the coordinate origin when storing the arrangements as templates.

FIG. 17 shows a configuration data structure 520 suitable for storing fingertip arrangement templates and associating them with particular modifier types. Thus configuration data structure 520 is an alternative to the modifier zone embodiment 100 of configuration data 54. It has a modifier type bitmask 102 and modifier hand source 104 equivalent to the modifier zone data structure 100. Each data structure 520 encodes one of the fingertip arrangements from FIG. 16 or the like as a template of four x offsets 526 and four y offsets 528 from the chord center 500. Encoding them as offsets from the centroid 500 of the 4 fingertip locations will help template matching in FIG. 18 be neutral to absolute hand position on the surface.

The pattern matching process of FIG. 18 selects the template arrangement that best matches the measured arrangement of fingertips performing a modifier chord. This arrangement matching process is thus an alternative to FIG. 10's modifier zone selection embodiment of block 164. An array AR[ ] of the template data structure 520 constitutes the data 54. Step 550 clears selected mods, the variable whose bits will hold the selected modifier types. Step 552 initializes min_sumdist2, the variable that will hold the lowest match error of evaluated templates, to a very large number. Step 555 compares the average or centroid, avg_fpos, of the four fingertip locations from the MT[ ] modifier touch array. Step 554 clears the arrangement template index i. Step 556 clears the squared error sum_dist2 for the current template AR[i]. Step 558 initializes the finger identity index to 2 indicating the index finger. Steps 560-564 then loop through to the pinky accumulating the squared error between each fingertip's offset from chord center and the corresponding template point's offset from chord center. Decision diamond 566 checks whether the squared error for template AR[i] make it the best match so far, and if so step 568 updates min_sumdist2 and step 570 stores template AR[i]'s modifier type 522 as the modifier selected so far. Decision diamond 572 determines whether all template arrangements have been tested, and if not step 574 advances the index i to the next template. Once all arrangements have been tested, step 576 will return the modifier type 522 of the template 520 which most closely matches the measured arrangement of modifier touches MT[ ].

Those with ordinary skill in the art will be able to adapt the present invention to use different finger combinations such as three fingertips, or a thumb and three fingertips for modifier chords. However, the four fingertip combination is both easiest to perform and by far most compatible with the typing, hand resting, and pointing activities that can also take place on a multi-touch surface. Using the thumb and three fingertips is a bit more awkward and would necessitate cancellation when the pinky, or in general, a fifth digit touched the surface before commit by other modifiable input activity. Using three fingertips for modifier chords would necessitate cancellation when either the thumb or a fourth fingertip from the modifier chord hand touched the surface before commit by modifiable activity on the opposite hand. Three fingertips modifier chords would also be incompatible with drag operations that are preferably assigned to three-fingertips on a multi-touch surface.

Though embodiments and applications of this invention have been shown and described, it will be apparent to those skilled in the art that numerous further embodiments and modifications than mentioned above are possible without departing from the inventive concepts disclosed herein. The invention, therefore, is not to be restricted except in the true spirit and scope of the appended claims.

Claims

1. A multi-touch surface apparatus that interprets 4-finger chords performed concurrently with other input activity as modifiers of that input activity, thereby avoiding awkward thumb or pinky reaches for conventional modifier keys, reducing hand strain and reducing the tendency of hands to drift off of home row, the apparatus comprising:

multiple-touch sensing means that reports the locations and times of finger contacts with a surface,
modifier configuration means establishes modifier zones as horizontal bands across the surface and associates each modifier zone with one or more modifier types;
synchronization detection means that scans for modifier chord touchdowns consisting of substantially simultaneous touches by four and no more than four digits of a hand;
modifier zone selection means that selects modifier types for the chord according to which modifier zones said simultaneous touches fall within;
chord cancellation means that cancels a modifier chord if the remaining unsynchronized digit from its hand touches before other modifiable input activity commits the chord;
modifier applicability search means that commits the modifier chord and sends modifier press signals corresponding to the chord's selected modifier types to a host computer upon detection of modifiable input activity that occurs substantially between touchdown and liftoff of the modifier chord; and,
chord liftoff detection means that reports when none of the digits originally constituting the modifier chord are touching the surface and sends modifier release signals to the host computer accordingly.

2. The apparatus of claim 1 wherein the apparatus additionally comprises a typing recognition means and surface key layout with a home row of keys upon which the hands normally rest, wherein the four digits that can constitute a modifier chord do not include the thumb, and wherein Shift modifier zones are configured along the home row of keys and other modifier types are configured for zones substantially above and below the home row of keys.

3. The apparatus of claim 2 wherein any Shift signals arising from a committed modifier chord are temporarily released during transmission to the host of keypress signals from a thumb key touch and then re-pressed if the modifier chord has not yet lifted.

4. The apparatus of claim 1 wherein the modifier zone selection means compensates for the natural arch in a row of relaxed fingers by computing for each touch of the modifier chord a vertical offset from a default location of the finger whose identity a contact identification means has assigned to the touch.

5. The apparatus of claim 4 wherein the modifier zone selection means simultaneously selects the modifier types from each zone within which any of the simultaneous touches fall except if some of the simultaneous touches are bunched straddling the border between two zones, in which case the modifier type associated with the single zone that the average of the vertical offsets lies within is selected.

6. The apparatus of claim 1 wherein the locations of the modifier zones on the surface are indicated to the user via printing on the surface background colors or textures unique to each zone.

7. The apparatus of claim 1 wherein the locations of the modifier zones on the surface are indicated to the user via active surface display of background colors or textures unique to each zone.

8. A multi-touch surface apparatus that interprets certain finger chords performed concurrently with other input activity as modifiers of that input activity, thereby avoiding awkward thumb or pinky reaches for conventional modifier keys, reducing hand strain and reducing the need to reposition the hands, the apparatus comprising:

multiple-touch sensing means that reports the locations and times of finger contacts with a surface;
modifier configuration means that establishes finger arrangement templates and associates each template with one or more modifier types;
synchronization detection means that scans for modifier chord touchdowns consisting of substantially simultaneous touches by a predetermined combination of digits of a hand;
finger arrangement matching means that selects for the chord the modifier types associated with the template that most closely matches the arrangement of the modifier chord touches;
chord cancellation means that cancels a modifier chord if the remaining digits from its hand not included in the predetermined combination touch before other modifiable input activity commits the chord;
modifier applicability search means that commits the modifier chord and sends modifier press signals corresponding to the chord's selected modifier types to a host computer upon detection of modifiable input activity that occurs substantially between touchdown and liftoff of the modifier chord; and
modifier chord liftoff detection means that reports when none of the digits originally constituting the modifier chord are touching the surface and sends modifier release signals to the host computer accordingly.

9. The apparatus of claim 8 wherein any Shift signals arising from a committed modifier chord are temporarily released during transmission to the host of keypress signals from thumb key touches and then re-pressed if the modifier chord has not yet lifted.

10. The apparatus of claim 8 wherein four fingertips excluding the thumb is used as the predetermined combination of digits, the neutral four fingertip arrangement of FIG. 16A is associated with the shift modifier type, and the horizontally spread arrangement template of FIG. 16B is associated with the Ctrl modifier type.

11. The apparatus of claim 8 wherein the template matching means computes the matching error as the sum of squared distances between each template point's offset from template center and the offset to the corresponding modifier chord touch from chord center, thus making the matching process independent of where the chord is performed on the surface.

12. A method of controlling a modifier on a multi-touch surface having a key layout thereon, the method comprising:

activating the modifier by simultaneously dropping a plurality of fingertips of a hand into a modifier zone on or near a home row of the key layout; and
maintaining activation of the modifier by leaving at least one of the plurality of fingertips in contact with the modifier zone.

13. The method of claim 12 further comprising:

deactivating the modifier by removing each of the plurality of fingertips from contact with the modifier zone.

14. The method of claim 12 further comprising:

deactivating the modifier by placing a thumb of the hand in contact with the key layout.

15. The method of claim 12 wherein the modifier zone on or near a home row of the key layout may be reached through straight flexion or extension of the fingers from their home row position.

16. The method of claim 12 further comprising:

concurrently activating a second modifier key by simultaneously dropping a plurality of fingertips of the hand into two modifier zones on or near a home row of the key layout, wherein the fingertips are clearly distributed into the two modifier zones.

17. A multi-touch surface having embodied thereon a key layout, the key layout comprising at least one modifier zone on or near a home row of the key layout wherein a modifier will be activated by the simultaneous touchdown of a plurality of fingertips within the at least one modifier zone and maintained by leaving at least one of the plurality of fingertips in contact with the modifier zone.

18. The multi-touch surface of claim 17 comprising a plurality of modifier zones on or near a home row of the key layout, wherein each modifier zone corresponds to a different modifier.

19. The multi-touch surface of claim 18 wherein each of the plurality of modifier zones is indicated by a different color.

20. A method of processing incoming signals from a multi-touch surface, the method comprising:

detecting modifier chords by monitoring the incoming touch sequence for simultaneous touchdowns of a plurality of fingertips of a hand within one or more predetermined modifier zones; and, if a new modifier chord is detected: allocating a corresponding modifier state data structure; and appending the modifier state data structure to a modifier chord state chain; and
checking for cancellation of a modifier chord; and, if cancellation of a modifier chord is detected: recording either a modifier chord liftoff time or modifier chord cancellation.

21. The method of claim 20 further comprising:

searching a modifier state chain for un-cancelled modifier chords roughly coincident with modifiable input activity; and, if any applicable modifier chords whose signals have not already been sent to a host computer are identified;
sending the modifier signals to the host computer.

22. A multi-touch surface apparatus comprising:

a multi-touch surface that reports the locations and times of finger contacts with a surface;
a synchronization detector that scans for modifier chord touchdowns consisting of substantially simultaneous touches by a plurality of digits of a hand in a pre-defined modifier zone on the multi-touch surface and sends modifier signals accordingly; and
a chord liftoff detector that reports when none of the digits originally constituting the modifier chord are touching the surface and sends modifier release signals accordingly.

23. The multi-touch surface apparatus of claim 22 wherein there are a plurality of pre-defined modifier zones on the multi-touch surface, each pre-defined modifier zone corresponding to a different modifier, the multi-touch surface apparatus further comprising:

a modifier zone selector that selects modifier types for the chord according to which modifier zones the simultaneous touches fall within.

24. The multi-touch surface apparatus of claim 23 further comprising:

a chord canceller that cancels a modifier chord if a remaining unsynchronized digit from the hand touches the multi-touch surface before other modifiable input activity commits the chord.

25. The multi-touch surface apparatus of claim 22 further comprising:

a chord canceller that cancels a modifier chord if a remaining unsynchronized digit from the hand touches the multi-touch surface before other modifiable input activity commits the chord.

26. The apparatus of any of claims 22-25 further comprising a key layout on the multi-touch surface, the key layout having a home row wherein a first modifier zone is configured along the home row.

27. The apparatus of claim 26 wherein at least one additional modifier zone is configured adjacent the home row.

28. The apparatus of claim 27 wherein the at least one additional modifier zone comprises a second modifier zone above the home row and a third modifier zone below the home row.

29. The apparatus of claim 28 wherein the modifiers corresponding to the first, second, and third modifier zones are selected from the group consisting of Shift, Ctrl, Alt, Windows, Open Apple, or Meta.

30. The apparatus of claim 26 wherein the location of the modifier zone is indicated by printing on the multi-touch surface.

31. The apparatus of claim 30 wherein the printing on the multi-touch surface comprises background color.

32. The apparatus of claim 26 wherein the location of the modifier zone is indicated by texture on the multi-touch surface.

33. The apparatus of any of claims 27-29, wherein the locations of the modifier zones are indicated by printing on the multi-touch surface.

34. The apparatus of claim 33 wherein the printing on the multi-touch surface comprises a unique background color for each zone.

35. The apparatus of claim 27-29 wherein the locations of the modifier zones are indicated by texture on the multi-touch surface.

36. The apparatus of claim 26 wherein the location of the modifier zone is indicated by active surface display of background color.

37. The apparatus of claim 26 wherein the location of the modifier zone is indicated by active surface display of texture.

38. The apparatus of any of claims 27-29 wherein the locations of the modifier zones are indicated by active surface display of background colors unique to each zone.

39. The apparatus of claim 27-29 wherein the locations of the modifier zones are indicated active surface display of textures unique to each zone.

40. A multi-touch surface apparatus comprising:

a multi-touch surface that reports the locations and times of finger contacts with a surface;
a synchronization detector that scans for modifier chord touchdowns consisting of substantially simultaneous touches by a predetermined combination of digits of a hand in a predetermined arrangement;
finger arrangement matcher that selects a modifier corresponding to the modifier chord and sends modifier signals accordingly; and
a chord liftoff detector that reports when none of the digits originally constituting the modifier chord are touching the surface and sends modifier release signals accordingly.

41. The multi-touch surface apparatus of claim 40 further comprising:

a chord canceller that cancels a modifier chord if the remaining digits from its hand not include in the predetermined combination touch before other modifiable input activity commits the chord.

42. The multi-touch surface apparatus of claim 40 or 41 wherein the predetermined arrangement is selected from the group consisting of a neutral fingertip arrangement and a spread fingertip arrangement.

43. The multi-touch surface apparatus of claim 42 wherein the modifiers associated with the predetermined arrangement are selected from the group consisting of: Shift, Ctrl, Alt, Windows, Open Apple, or Meta.

Referenced Cited

U.S. Patent Documents

3333160 July 1967 Gorski
3541541 November 1970 Englebart
3662105 May 1972 Hurst et al.
3798370 March 1974 Hurst
4246452 January 20, 1981 Chandler
4550221 October 29, 1985 Mabusth
4672364 June 9, 1987 Lucas
4672558 June 9, 1987 Beckes et al.
4692809 September 8, 1987 Beining et al.
4695827 September 22, 1987 Beining et al.
4733222 March 22, 1988 Evans
4734685 March 29, 1988 Watanabe
4746770 May 24, 1988 McAvinney
4771276 September 13, 1988 Parks
4788384 November 29, 1988 Bruere-Dawson et al.
4806846 February 21, 1989 Kerber
4898555 February 6, 1990 Sampson
4968877 November 6, 1990 McAvinney et al.
5003519 March 26, 1991 Noirjean
5017030 May 21, 1991 Crews
5178477 January 12, 1993 Gambaro
5189403 February 23, 1993 Franz et al.
5194862 March 16, 1993 Edwards
5224861 July 6, 1993 Glass et al.
5241308 August 31, 1993 Young
5252951 October 12, 1993 Tannenbaum et al.
5281966 January 25, 1994 Walsh
5305017 April 19, 1994 Gerpheide
5345543 September 6, 1994 Capps et al.
5376948 December 27, 1994 Roberts
5398310 March 14, 1995 Tchao et al.
5442742 August 15, 1995 Greyson et al.
5463388 October 31, 1995 Boie et al.
5463696 October 31, 1995 Beernink et al.
5483261 January 9, 1996 Yasutake
5488204 January 30, 1996 Mead et al.
5495077 February 27, 1996 Miller et al.
5513309 April 30, 1996 Meier et al.
5523775 June 4, 1996 Capps
5530455 June 25, 1996 Gillick et al.
5543590 August 6, 1996 Gillespie et al.
5543591 August 6, 1996 Gillespie et al.
5563632 October 8, 1996 Roberts
5563996 October 8, 1996 Tchao
5565658 October 15, 1996 Gerpheide et al.
5579036 November 26, 1996 Yates, IV
5581681 December 3, 1996 Tchao et al.
5583946 December 10, 1996 Gourdol
5590219 December 31, 1996 Gourdol
5592566 January 7, 1997 Pagallo et al.
5594810 January 14, 1997 Gourdol
5596694 January 21, 1997 Capps
5612719 March 18, 1997 Beernink et al.
5631805 May 20, 1997 Bonsall
5633955 May 27, 1997 Bozinovic et al.
5634102 May 27, 1997 Capps
5636101 June 3, 1997 Bonsall et al.
5642108 June 24, 1997 Gopher et al.
5644657 July 1, 1997 Capps et al.
5666113 September 9, 1997 Logan
5666502 September 9, 1997 Capps
5666552 September 9, 1997 Grayson et al.
5675361 October 7, 1997 Santilli
5677710 October 14, 1997 Thompson-Rohrlich
5689253 November 18, 1997 Hargreaves et al.
5710844 January 20, 1998 Capps et al.
5729250 March 17, 1998 Bishop et al.
5730165 March 24, 1998 Philipp
5736976 April 7, 1998 Cheung
5741990 April 21, 1998 Davies
5745116 April 28, 1998 Pisutha-Arnond
5745716 April 28, 1998 Tchao et al.
5746818 May 5, 1998 Yatake
5748269 May 5, 1998 Harris et al.
5764222 June 9, 1998 Sheih
5767457 June 16, 1998 Gerpheide et al.
5767842 June 16, 1998 Korth
5790104 August 4, 1998 Shieh
5790107 August 4, 1998 Kasser et al.
5802516 September 1, 1998 Shwarts et al.
5808567 September 15, 1998 McCloud
5809267 September 15, 1998 Moran et al.
5821690 October 13, 1998 Martens et al.
5821930 October 13, 1998 Hansen
5823782 October 20, 1998 Marcus et al.
5825351 October 20, 1998 Tam
5825352 October 20, 1998 Bisset et al.
5854625 December 29, 1998 Frisch et al.
5880411 March 9, 1999 Gillespie et al.
5898434 April 27, 1999 Small et al.
5920309 July 6, 1999 Bisset et al.
5923319 July 13, 1999 Bishop et al.
5933134 August 3, 1999 Shieh
5943044 August 24, 1999 Martinelli et al.
6002389 December 14, 1999 Kasser
6002808 December 14, 1999 Freeman
6020881 February 1, 2000 Naughton et al.
6031524 February 29, 2000 Kunert
6037882 March 14, 2000 Levy
6050825 April 18, 2000 Nichol et al.
6052339 April 18, 2000 Frenkel et al.
6072494 June 6, 2000 Nguyen
6084576 July 4, 2000 Leu et al.
6107997 August 22, 2000 Ure
6128003 October 3, 2000 Smith et al.
6131299 October 17, 2000 Raab et al.
6135958 October 24, 2000 Mikula-Curtis et al.
6144380 November 7, 2000 Shwarts et al.
6188391 February 13, 2001 Seely et al.
6198515 March 6, 2001 Cole
6208329 March 27, 2001 Ballare
6222465 April 24, 2001 Kumar et al.
6239790 May 29, 2001 Martinelli et al.
6243071 June 5, 2001 Shwarts et al.
6246862 June 12, 2001 Grivas et al.
6249606 June 19, 2001 Kiraly et al.
6288707 September 11, 2001 Philipp
6289326 September 11, 2001 LaFleur
6292178 September 18, 2001 Bernstein et al.
6323846 November 27, 2001 Westerman et al.
6347290 February 12, 2002 Bartlett
6377009 April 23, 2002 Philipp
6380931 April 30, 2002 Gillespie et al.
6411287 June 25, 2002 Scharff et al.
6414671 July 2, 2002 Gillespie et al.
6421234 July 16, 2002 Ricks et al.
6452514 September 17, 2002 Philipp
6457355 October 1, 2002 Philipp
6466036 October 15, 2002 Philipp
6515669 February 4, 2003 Mohri
6525749 February 25, 2003 Moran et al.
6535200 March 18, 2003 Philipp
6543684 April 8, 2003 White et al.
6543947 April 8, 2003 Lee
6570557 May 27, 2003 Westerman et al.
6593916 July 15, 2003 Aroyan
6610936 August 26, 2003 Gillespie et al.
6624833 September 23, 2003 Kumar et al.
6639577 October 28, 2003 Eberhard
6650319 November 18, 2003 Hurst et al.
6658994 December 9, 2003 McMillan
6670894 December 30, 2003 Mehring
6677932 January 13, 2004 Westerman
6677934 January 13, 2004 Blanchard
6724366 April 20, 2004 Crawford
6757002 June 29, 2004 Oross
6803906 October 12, 2004 Morrison et al.
6842672 January 11, 2005 Straub et al.
6856259 February 15, 2005 Sharp
6888536 May 3, 2005 Westerman et al.
6900795 May 31, 2005 Knight, III et al.
6927761 August 9, 2005 Badaye et al.
6942571 September 13, 2005 McAllister et al.
6965375 November 15, 2005 Gettemy et al.
6972401 December 6, 2005 Akitt et al.
6977666 December 20, 2005 Hedrick
6985801 January 10, 2006 Straub et al.
6992659 January 31, 2006 Gettemy
7031228 April 18, 2006 Born et al.
20020118848 August 29, 2002 Karpenstein
20030006974 January 9, 2003 Clough et al.
20030076301 April 24, 2003 Tsuk et al.
20030076303 April 24, 2003 Huppi
20030076306 April 24, 2003 Zadesky et al.
20030095095 May 22, 2003 Pihlaja
20030095096 May 22, 2003 Robbin et al.
20030098858 May 29, 2003 Perski et al.
20030206202 November 6, 2003 Moriya
20030234768 December 25, 2003 Rekimoto et al.
20040263484 December 30, 2004 Montysalo et al.
20050012723 January 20, 2005 Pallakoff
20050052425 March 10, 2005 Zadesky et al.
20050104867 May 19, 2005 Westerman et al.
20050110768 May 26, 2005 Marriott et al.
20060022955 February 2, 2006 Kennedy
20060022956 February 2, 2006 Lengeling et al.
20060026521 February 2, 2006 Hotelling et al.
20060026535 February 2, 2006 Hotelling et al.
20060026536 February 2, 2006 Hotelling et al.
20060032680 February 16, 2006 Elias et al.
20060033724 February 16, 2006 Chaudhri et al.
20060053387 March 9, 2006 Ording
20060066582 March 30, 2006 Lyon et al.
20060085757 April 20, 2006 Andre et al.
20060097991 May 11, 2006 Hotelling et al.
20060197753 September 7, 2006 Hotelling

Foreign Patent Documents

1243096 October 1988 CA
102 51 296 May 2004 DE
0 288 692 July 1993 EP
0 664 504 January 1995 EP
0 464 908 September 1996 EP
1 014 295 January 2002 EP
1997/018547 May 1997 WO
1997/023738 July 1997 WO
1998/14863 April 1998 WO
2003/088176 October 2003 WO
2006/023569 March 2006 WO

Other references

  • U.S. Appl. No. 10/654,108, filed Sep. 2, 2003 entitled “Ambidextrous Mouse”.
  • U.S. Appl. No. 10/789,676, filed Feb. 27, 2004 entitled “Shape Detecting Input Device”.
  • “4-Wire Resistive Touchscreens” obtained from http://www.touchscreens.com/intro-touchtypes-4resistive.html generated Aug. 5, 2005.
  • “5-Wire Resistive Touchscreens” obtained from http://www.touchscreens.com/intro-touchtypes-resistive.html generated Aug. 5, 2005.
  • “A Brief Overview of Gesture Recognition” obtained from http://www.dai.ed.ac.uk/Cvonline/LOCA_COPIES/COHEN/gesture_overview.html, generated Apr. 20, 2004.
  • “Capacitive Touchscreens” obtained from http://www.touchscreens.com/intro-touchtypes-capacitive.html generated Aug. 5, 2005.
  • “Capacitive Position Sensing” obtained from http://www.synaptics.com/technology/cps.cfm generated Aug. 5, 2005.
  • “Comparing Touch Technologies” obtained from http://www.touchscreens.com/intro-touchtypes.html generated Oct. 10, 2004.
  • “Gesture Recognition” http://www.fingerworks.com/gesture_recognition.html.
  • “GlidePoint®” obtained from http://www.cirque.com/technology/technology_gp.html generated Aug. 5, 2005.
  • “How do touchscreen monitors know where you're touching?” obtained from http://www.electronics.howstuffworks.com/question716.html generated Aug. 5, 2005.
  • “How does a touchscreen work?” obtained from http://www.touchscreens.com/intro-anatomy.html generated Aug. 5, 2005.
  • “iGesture Products for Everyone (learn in minutes) Product Overview” FingerWorks.com.
  • “Infrared Touchscreens” obtained from http://www.touchscreens.com/intro-touchtypes-infrared.html generated Aug. 5, 2005.
  • “Mouse Emulation” FingerWorks obtained from http://www.fingerworks.com/gesture_guide_mouse.html generated Aug. 30, 2005.
  • “Mouse Gestures in Opera” obtained from http://www.opera.com/products/desktop/mouse/index.dml generated Aug. 30, 2005.
  • “Mouse Gestures,” Optim oz, May 21, 2004.
  • “MultiTouch Overview” FingerWorks obtained from http://www.fingerworks.com/multoverview.html generated Aug. 30, 2005.
  • “Near Field Imaging Touchscreens” obtained from http://www.touchscreens.com/intro-touchtypes.nfi.html generated Aug. 5, 2005.
  • “PenTouch Capacitive Touchscreens” obtained from http://www.touchscreens.com/intro-touchtypes-pentouch.html generated Aug. 5, 2005.
  • “Surface Acoustic Wave Touchscreens” obtained from http://www.touchscreens.com/intro-touchtypes.saw.html generated Aug. 5, 2005.
  • “Symbol Commander” obtained from http://www.sensiva.com/symbolcomander/, generated Aug. 30, 2005.
  • “Tips for Typing” FingerWorks http://www.fingerworks.com/mini_typing.html generated Aug. 30, 2005.
  • “Touch Technologies Overview” 2001, 3M Touch Systems, Massachusetts.
  • “Wacom Components—Technology” obtained from http://www.wacom-components.com/english/tech.asp generated on Oct. 10, 2004.
  • “Watershed Algorithm” http://rsb.info.nih.gov/ij/plugins/watershed.html generated Aug. 5, 2005.
  • “FingerWorks—Gesture Guide—Application Switching,” obtained from http://www.fingerworks.com/gesture_guide_apps.html, generated on Aug. 27, 2004, 1-pg.
  • “FingerWorks—Gesture Guide—Editing,” obtained from http://www.fingerworks.com/gesure_guide_editing.html, generated on Aug. 27, 2004, 1-pg.
  • “FingerWorks—Gesture Guide—File Operations,” obtained from http://www.fingerworks.com/gesture_guide_files.html, generated on Aug. 27, 2004, 1-pg.
  • “FingerWorks—Gesture Guide—Text Manipulation,” obtained from http://www.fingerworks.com/gesture_guide_text_manip.html, generated on Aug. 27, 2004, 2-pg.
  • “FingerWorks—Gesture Guide—Tips and Tricks,” obtained from http://www.fingerworks.com/gesture_guide_tips.html, generated Aug. 27, 2004, 2-pgs.
  • “FingerWorks—Gesture Guide—Web,” obtained from http://www.fingerworks.com/gesture_guide_web.html, generated on Aug. 27, 2004, 1-pg.
  • “FingerWorks—Guide to Hand Gestures for USB Touchpads,” obtained from http://www.fingerworks.com/igesture_userguide.html, generated Aug. 27, 2004, 1-pg.
  • “FingerWorks—iGesture—Technical Details,” obtained from http://www.fingerworks.com/igesture_tech.html, generated Aug. 27, 2004, 1-pg.
  • “FingerWorks—The Only Touchpads with Ergonomic Full-Hand Resting and Relaxation!” obtained from http://www.fingerworks.com/resting.html, Copyright 2001, 1-pg.
  • “FingerWorks—Tips for Typing on the Mini,” obtained from http://www.fingerworks.com/mini_typing.html, generated on Aug. 27, 2004, 2-pgs.
  • “iGesture Pad—the MultiFinger USB TouchPad with Whole-Hand Gestures,” obtained from http://www.fingerworks.com/igesture.html, generated Aug. 27, 2004, 2-pgs.
  • Bier, et al., “Toolglass and Magic Lenses: The see-through interface” In James Kijiya, editor, Computer Graphics (SIGGRAPH '93 Proceedings), vol. 27, pp. 73-80, Aug. 1993.
  • Douglas et al., The Ergonomics of Computer Pointing Devices (1997).
  • European Search Report received in EP 1 621 989 (@ Beyer Weaver & Thomas, LLP) dated Mar. 27, 2006.
  • EVB Elektronik “TSOP6238 IR Receiver Modules for Infrared Remote Control Systems” dated Jan. 2004 1-pg.
  • Fisher et al., “Repetitive Motion Disorders: The Design of Optimal Rate—Rest Profiles,” Human Factors, 35(2):283-304 (Jun. 1993).
  • Fukumoto, et al., “ActiveClick: Tactile Feedback for Touch Panels,” In CHI 2001 Summary, pp. 121-122, 2001.
  • Fukumoto and Yoshinobu Tonomura, “Body Coupled Fingering: Wireless Wearable Keyboard,” CHI 97, pp. 147-154 (Mar. 1997).
  • Hardy, “Fingerworks” Mar. 7, 2002; BBC World On Line.
  • Hillier and Gerald J. Lieberman, Introduction to Operations Research (1986).
  • International Search Report dated Mar. 3, 2006 (PCT/US 05/03325; 119-0052WO).
  • Jacob et al., “Integrality and Separability of Input Devices,” ACM Transactions on Computer-Human Interaction, 1:3-26 (Mar. 1994).
  • Kinkley et al., “Touch-Sensing Input Devices,” in CHI '99 Proceedings, pp. 223-230, 1999.
  • Kionx “KXP84 Series Summary Data Sheet” copyright 2005,dated Oct. 21, 2005, 4-pgs.
  • Lee et al., “A Multi-Touch Three Dimensional Touch-Sensitive Tablet,” in CHI '85 Proceedings, pp. 121-128, 2000.
  • Lee, “A Fast Multiple-Touch-Sensitive Input Device,” Master's Thesis, University of Toronto (1984).
  • Matsushita et al., “HoloWall: Designing a Finger, Hand, Body and Object Sensitive Wall,” In Proceedings of UIST '97, Oct. 1997.
  • Quantum Research Group “QT510 / QWheel™ Touch Slider IC” copyright 2004-2005, 14-pgs.
  • Quek, “Unencumbered Gestural Interaction,” IEEE Multimedia, 3:36-47 (Winter 1996).
  • Radwin, “Activation Force and Travel Effects on Overexertion in Repetitive Key Tapping,” Human Factors, 39(1):130-140 (Mar. 1997).
  • Rekimoto “SmartSkin: An Infrastructure for Freehand Manipulation on Interactive Surfaces” CHI 2002, Apr. 20-25, 2002.
  • Rekimoto et al., “ToolStone: Effective Use of the Physical Manipulation Vocabularies of Input Devices,” In Proc. Of UIST 2000, 2000.
  • Rubine et al., “Programmable Finger-Tracking Instrument Controllers” Computer Music Journal, vol. 14, No. 1 (Spring 1990).
  • Rutledge et al., “Force-To-Motion Functions For Pointing,” Human-Computer Interaction—INTERACT (1990).
  • Subatai Ahmad, “A Usable Real-Time 3D Hand Tracker,” Proceedings of the 28th Asilomar Conference on Signals, Systems and Computers—Part 2 (of2), vol. 2 (Oct. 1994).
  • Texas Instruments “TSC2003 / I2C Touch Screen Controller” Data Sheet SBAS 162, dated Oct. 2001, 20-pgs.
  • Wellner, “The Digital Desk Calculators: Tangible Manipulation on a Desk Top Display” IN ACM UIST '91 Proceedings, pp. 27-34, Nov. 1991.
  • Williams, “Applications for a Switched-Capacitor Instrumentation Building Block” Linear Technology Application Note 3, Jul. 1985, pp. 1-16.
  • Yamada et al., “A Switched-Capacitor Interface for Capacitive Presssure Sensors” IEEE Transactions on Instrumentation and Measurement, vol. 41, No. 1, Feb. 1992, pp. 81-86.
  • Yeh et al., “Switched Capacitor Interface Circuit for Capacitive Transducers” 1985 IEEE.
  • Zhai et al., “Dual Stream Input for Pointing and Scrolling,” Proceedings of CHI '97 Extended Abstracts (1997).
  • Zimmerman et al., “Applying Electric Field Sensing to Human-Computer Interfaces,” In CHI '85 Proceedings, pp. 280-287, 1995.
  • U.S. Appl. No. 10/774,053, filed on Feb. 5, 2004.
  • U.S. Appl. No. 11/140,529, filed May 27, 2005 which is a Reissue of 6,570,557.
  • U.S. Appl. No. 11/381,313, filed May 2, 2006 entitled “Multipoint Touch Surface Controller”.
  • U.S. Appl. No. 11/332,861, filed Jan. 13, 2006 which is a Reiuuse of 6,677,932.
  • U.S. Appl. No. 11/380,109, filed Apr. 25, 2006 entitled “Keystroke Tactility Arrangement On Smooth Touch Surface.”
  • U.S. Appl. No. 11/428,501, filed Jul. 3, 2006 entitled “Capacitive Sensing Arrangement,” which is a Continuation of US 2005/0104867.
  • U.S. Appl. No. 11/428,503, filed Jul. 3, 2006 entitled “Touch Surface” which is a Continuation of US 2005/0104867.
  • U.S. Appl. No. 11/428,506, filed Jul. 3, 2006 entitled “User Interface Gestures” which is a Continuation of US 2005/0104867.
  • U.S. Appl. No. 11/428,515, filed Jul. 3, 2006 entitled “User Interface Gestures” which is a Continuation of US 2005/0104867.
  • U.S. Appl. No. 11/428,522, filed Jul. 3, 2006 entitled “Identifying Contacts on a Touch Surface” which is a Continuation of US 2005/0104867.
  • U.S. Appl. No. 11/428,521, filed Jul. 3, 2006 entitled “Identifying Contacts on a Touch Surface” which is a Continuation of US 2005/0104867.
  • U.S. Appl. No. 11/426,078, filed Jun. 23, 2006 entitled “Electronic Device Having Display and Surrounding Touch Sensitive Bezel For User Interface and Control” which is a Continuation-In-Part of 2006/0197753.
  • U.S. Appl. No. 11/278,080, filed Mar. 30, 2006 entitled “Force Imaging Input Device and System”.
  • U.S. Appl. No. 11/382,402, filed May 9, 2006 entitled “Force and Location Sensitive Display” which is a Continuation of U.S. Appl. No. 11/278,080.
  • International Search Report received in corresponding PCT application No. PCT/US2006/008349 dated Oct. 6, 2006.

Patent History

Patent number: RE40153
Type: Grant
Filed: May 27, 2005
Date of Patent: Mar 18, 2008
Assignee: Apple Inc. (Cupertino, CA)
Inventors: Wayne Carl Westerman (San Francisco, CA), John Greer Elias (Townsend, DE)
Primary Examiner: Alexander Eisen
Attorney: Morrison & Foerster LLP
Application Number: 11/140,529