Abstract:
Disclosed are four arrangements for providing tactility on a touch surface keyboard. One approach is to provide tactile feedback mechanisms, such as dots, bars, or other shapes on all or many keys. In another embodiment, an articulating frame may be provided that extends when the surface is being used in a typing mode and retracts when the surface is used in some other mode, e.g., a pointing mode. The articulating frame may provide key edge ridges that define the boundaries of the key regions or may provide tactile feedback mechanisms within the key regions. The articulating frame may also be configured to cause concave depressions similar to mechanical key caps in the surface. In another embodiment, a rigid, non-articulating frame may be provided beneath the surface. A user will then feel higher resistance when pressing away from the key centers, but will feel a softer resistance at the key center.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is related to the following patents and patent applications, which are all herein incorporated by reference: (1) U.S. Pat. No. 6,323,846, titled “Method and Apparatus for Integrating Manual Input,” issued on Jul. 1, 2002; (2) U.S. Pat. No. 6,677,932, titled “System and Method for Recognizing Touch Typing Under Limited Tactile Feedback Conditions,” issued on Jan. 13, 2004; and (3) U.S. Pat. No. 6,570,557, titled “Multi-Touch System and Method for Emulating Modifier Keys Via Fingertip Chords,” issued on May 27, 2003. 
     BACKGROUND 
     Integration of typing, pointing, and gesture capabilities into touch surfaces offers many advantages, such as eliminating need for mouse as a separate pointing device, eliminating wasteful reaches between keyboard and pointing device, and general workflow streamlining. However, pointing and typing have opposite tactile feedback needs. Specifically, pointing and gesturing inputs are best accomplished using a smooth, nearly frictionless touch surface. Conversely, typists are accustomed to relying on sharp key edges for tactile feedback. 
     User acceptance of the TouchStream™ integrated typing, pointing and gesture input devices manufactured by FingerWorks demonstrated that learning to type on a smooth, un-textured surface is possible, but takes substantial practice. In many ways, typing on such a surface is almost like learning to type all over again. It is believed that mainstream acceptance of typing on touch surfaces will require shortening of the typing re-acclimation period, which, in turn, requires improved keystroke tactility. 
     Traditionally, keystroke tactility on a surface or “membrane” keyboard has been provided by indicating key edges using hydroformed or stamped raised ridges into the surface plastic. However, this technique has several disadvantages for touch surfaces also intended for pointing and gesture. For example, the key-edge ridges impede lateral pointing motions, giving the surface a rough washboard feel. The ridges also disrupt position interpolation from capacitive sensor arrays as the fingertip flesh lifts over the ridge. 
     In a more successful attempt to provide surface keyboard users with suitable tactile feedback, keyboards incorporating home row dimples as disclosed in U.S. Pat. No. 6,323,846, referenced above, were produced. These dimples helped users find the home row keys when hands were resting on the surface, while minimizing disruption of a user&#39;s motion in pointing or gesturing on the surface. However, these dimples were ineffective feedback for helping users feel for keys away from home row, or detect when they were not striking the centers of these peripheral keys. 
     Another somewhat successful prior method for aligning hands on both surface and traditional mechanical keyboards has been to place a single raised Braille-like dot on an “alignment” key or on the “home row” of keys. For example, many mechanical keyboards features such raised dots on the “F” and “J” keys, which are the index finger home positions for a touch typist using QWERTY keyboard. As with the dimples disclosed in the &#39;846 patent, this arrangement is useful to help align a user&#39;s hands to home row, but does not help to correct alignment errors while reaching for peripheral keys. Thus, a significant problem arises in attempting to provide feedback of key positions away from the home row. 
     Placing alignment dots, such as the single Braille-like dot, at the center of every key would provide feedback for key positions away from the home row. However, such an arrangement would eliminate the distinctiveness of the home row keys, and create more ambiguous feedback for the user. Therefore, what is needed in the art is a way to provide tactility to all or at least a substantial number of keys without creating such a bumpy surface that pointing and gestures are uncomfortable or unsteady. 
     This could be accomplished by adapting known prior art Braille displays. In this approach, tiny, individually actuated pins spread across the keyboard could provide dynamic tactility, but at great mechanical cost and complexity. Thus, what is needed to reduce cost and complexity is a way to provide tactility for each key without placing individual electromagnetic actuators under each key. 
     An additional issue arises in that multi-touch capacitive sensor arrays, which are often used to form the multi-touch surfaces, are typically built with row and column electrodes spanning the surface, or with row and column drive/sense line accessing electronic buffers at each electrode cell. Thus whatever tactility mechanism is provided, the arrangement must be routable around the row/column electrodes or drive lines of multi-touch sensors without requiring additional circuit board vias or layers. 
     Disclosed herein are a variety of techniques for providing tactile feedback in a surface or other keyboard that address one or more of these deficiencies of the prior art. 
     SUMMARY 
     Disclosed herein are four arrangements for providing tactility on a touch surface keyboard. One approach is to provide tactile feedback mechanisms, such as dots, bars, or other shapes on all or at least many keys. Different keys or groups of keys may have different feedback mechanisms, e.g., a first feedback mechanism may be assigned to “home row” keys, with a second feedback mechanism assigned to keys adjacent the home row, with a third assigned to peripheral keys, which are neither home row keys nor adjacent the home row. Alternatively, an articulating frame may be provided that extends when the surface is being used in a typing mode and retracts when the surface is used in some other mode, e.g., a pointing mode. The articulating frame may provide key edge ridges that define the boundaries of the key regions or may be used to provide tactile feedback mechanisms within the key regions. The articulating frame may also be configured to cause concave depressions similar to mechanical key caps in the surface. In another embodiment, a rigid, non-articulating frame may be provided beneath the surface. A user will then feel higher resistance when pressing away from the key centers, but will feel a softer resistance, which may be enhanced by filling the gaps with a foam or gel material or air. 
     Using these arrangements, as well as individual elements of each or combinations thereof, it is possible to provide strong tactile feedback of each key location without impeding pointing, gestures, or related lateral sliding motions on the same touch surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a top view of a surface keyboard employing a tactile feedback mechanism. 
         FIG. 2  is a cross-section view of the surface keyboard depicted in  FIG. 1 . 
         FIG. 3  is a top view of a surface keyboard employing a variation of the tactile feedback mechanism depicted in  FIGS. 1 and 2 . 
         FIG. 4  is a cross-section view of the surface keyboard depicted in  FIG. 3 . 
         FIG. 5  is a cross-section view of a surface keyboard employing an alternative tactile feedback arrangement including an articulating frame (shown in an extended position). 
         FIG. 6  is a cross-section view of the surface keyboard illustrated in  FIG. 5  with the articulating frame shown in a retracted position. 
         FIG. 7  is a plan view of the surface keyboard illustrated in  FIGS. 5 and 6 . 
         FIGS. 8A and 8B  illustrate a cross-section view of a surface keyboard tactile feedback arrangement for simulating concave key cap centers. 
         FIG. 9  illustrates a cross-section view of a surface keyboard employing a deformable material beneath the keys to provide tactile feedback. 
     
    
    
     DETAILED DESCRIPTION 
     Braille-Like Dot Pairs or Bars at Key Centers 
     With reference now to  FIGS. 1 and 2 , one technique for providing tactile feedback in a surface keyboard is depicted.  FIG. 1  is a vertical view of a surface keyboard  100 .  FIG. 2  is a cross-section view of surface keyboard  100 . Surface keyboard  100  includes numerous key regions  101 . As used herein, the term “key” may also refer to the key regions  101 , although in a surface keyboard there is actually no mechanical key. Rather, sensing circuitry  111  disposed beneath the surface cover  112  detects an object, such as a user&#39;s finger, in contact or close proximity with the key regions  101  and outputs the corresponding letter, number, or symbol to a host computer or other device (not shown). The key layout shown in  FIG. 1  is a slightly modified QWERTY layout, which has been ergonomically designed to provide a more comfortable typing position. 
     Key regions  101  are arranged in a plurality of rows. As known to touch typists, the row of keys containing the letters “ASDF” on the left-hand side and “JKL;” on the right-hand side are known as the home row  102 . The home row is so called because a touch typist will keep the four fingers of each hand over these characters when a finger is not reaching for a key in another row. Adjacent rows  103  are the rows immediately adjacent, for example, the rows containing “QWER” and “ZXCV.” The remaining rows are known as peripheral rows  104 , for example, the row of number keys. 
     One mechanism to provide more robust tactile feedback for a user of a surface keyboard is to stamp two horizontally aligned dots  105  at the center of each home row key  106 . Similarly, two vertically aligned dots  107  may be stamped on each adjacent key  108 . Finally, a single dot  109  may be stamped on peripheral keys  110 . Because the home row keys feel different than all other keys, home row  102  may be easily found without looking when sliding hands over the surface. The two vertical dots  107  on adjacent keys  108  in turn help distinguish their feel from peripheral number and punctuation keys having only one raised dot  110 . 
     It will be appreciated that the particular arrangement of dots could vary from that described. For example, a single dot could be used to mark home row keys  102 , with two horizontal dots used for adjacent keys  103  and two vertical dots used for peripheral keys  104 . All that is required is that one unique tactile feedback mechanism, such as raised dots, be used for home row keys, while another is used for adjacent and/or peripheral keys. It is not required that the adjacent keys and peripheral keys employ different tactile feedback mechanisms, although it may be preferable to do so. 
     Moreover, the tactile feedback mechanism need not be limited to raised dots. In a variation of this technique, shown in plan-view in  FIG. 3  and in cross-section in  FIG. 4 , the a raised dot pair is replaced with a raised “hyphen,” i.e., a short bar  113 . The short bars  113  may be, for example, arranged horizontally ( 113   a ) at the centers of home row keys  106  and vertically ( 113   b ) on keys adjacent to home row  102 . Peripheral keys  110  may include a single raised dot  109 . Other shapes, such as squares, circles, triangles, etc. could also be used so long as the arrangements used for home row keys  102  are distinct from those used for the adjacent keys  103  and/or peripheral keys  104 . These embodiments may be less desirable than a raised dot pair in terms of efficient tactility and minimizing sensor distortion. However, these raised bars or other shapes may be more aesthetically pleasing than raised dot pairs. 
     It should also be noted that, although the tactile feedback arrangement described above has particular applicability to surface keyboards, it could also be used in conjunction with traditional mechanical/electromechanical keyboards. Additionally, although described in terms of the traditional QWERTY keyboard, the techniques may also be applied to other keyboard layouts, such as Dvorak keyboard, foreign language keyboards, court reporting machine keyboards, and other keyboard-like input devices. 
     Articulating Frame Protrudes at Key Edges During Typing 
     An alternative technique for providing tactile feedback in a surface keyboard will now be described with respect to  FIGS. 5 ,  6 , and  7 .  FIGS. 5 and 6  depict a cross-section view of the keyboard, while  FIG. 7  depicts a plan view. As illustrated in  FIGS. 5 and 6 , the surface keyboard  200  comprises a plurality of layers including an enclosure base  201 , the electrode circuit board  202 , and the surface cover  203 . Details of the construction of these devices are described in the various incorporated references and are not repeated here. 
     Additionally, the keyboard  200  includes an articulating frame  204 , which is disposed beneath the circuit board  202 . The articulating frame  204  may be raised and lowered by actuators  205 , which preferably take the form of electromagnetic actuators. Raising and lowering the articulating frame extends and withdraws key edge ridges  206 , which are dots or bars that poke through the keyboard surface when extended. Electromagnetic actuators  205  would raise the frame when operating in a typing mode such that the tops of the key edge ridges  206  are about 1 mm above the surface cover  203 . The electromagnetic actuators  205  would lower the frame when operating in a pointing/gesture mode such that the tops of the key edge ridges  206  are flush with surface cover  203 , thereby providing a substantially smooth surface for pointing and gesturing. Although electromagnetic actuators  205  are depicted as being disposed beneath the frame and above the enclosure bottom, they may be disposed in any arrangement that allows them to suitably displace the frame  204  and key edge ridges  206 . 
     Preferably, each key edge comprises one to four distinct bars or Braille-like dots. When constructed in conjunction with a capacitive multi-touch surface, the key edge ridges should separated to accommodate the routing of the drive electrodes, which may take the form of rows, columns, or other configurations. As an alternative to key edge ridges  206 , the frame could cause Braille-like dots or similar markers, as discussed above with respect to  FIGS. 1-4  to protrude through the key centers, although this arrangement would potentially interfere with touch detection and measurement because it would require mechanical devices in proximity to the key center, which is a preferred sensor location. In yet another alternative arrangement, articulating frame  204  could be disposed above the electrode circuit board  202 , although the added separation between the surface cover  203  and the circuit board  202  could complicate the touch measurement and detection. 
     The electromagnetic actuators may be located at the corners and/or center of the frame or distributed variously throughout the frame. Selection of a particular position will necessitate the determination of a variety of design parameters, such as frame material strength, power routing, cost, etc., all of which would be within the abilities of one skilled in the art having the benefit of this disclosure. The actuators  205  may be activated manually, for example, by touching the surface in a particular region, pressing a dedicated button, activating a switch, etc. Alternatively, the actuators raise and lower the frame according to mode commands from gesture and typing recognition software, such as that described in the &#39;846 patent incorporated by reference above. 
     Specifically, the recognition software commands lowering of the frame when lateral sliding gestures or mouse clicking activity chords are detected on the surface. Alternatively, when homing chords (i.e., placing the fingers on the home row) or asynchronous touches (typing activity) is detected on the surface, the recognition software commands raising of the frame. Various combinations or subsets of these recognition techniques could also be used. For example, the device may activate a typing mode when homing chords or asynchronous touches are detected and deactivate the typing mode if neither is detected for a some time interval. In this configuration the device effectively defaults to a pointing mode and switches to a typing mode when necessary. Conversely, the device could activate a pointing mode when lateral sliding gestures or mouse clicking activity is detected and switch to a typing mode when these activities are not detected for some time interval. In any case, the frame will change modes automatically from lowered and flush (pointing mode) to poking through the surface (typing mode) as often as the operator switches between pointing and typing. Of course, operators who did not like the automated behavior could manually toggle the frame state with a pre-assigned gesture. 
     When extended, the key edge bars  206  provide similar tactile feel to a conventional mechanical key edge when the finger straddles two keys. However, this arrangement does not effectively simulate the concave depression common in mechanical keycaps, which helps a typists fingers sink towards the key center. Obviously, the key edge bars  206  will only be felt if fingers touch way off key center. Additionally, the holes in surface cover  203  through which the key edge bars  206  extend may collect dirt and grime. However, an extension of this arrangement may be used to address these concerns. 
     Articulating Frame Deforms Surface Cover at Key Edges During Typing 
     Illustrated in  FIGS. 8A and 8B  is a variation of the articulating frame arrangement discussed above with respect to  FIGS. 5 ,  6 , and  7 .  FIG. 8A  shows the frame in the raised (typing) position, while  FIG. 8B  shows the frame in the lowered (pointing, gesturing, etc.) position. In this embodiment, the bars of articulating frame  304  protrude through the circuit board  302 , but not through the surface cover  303 . When actuators  305 , disposed between enclosure base  301  and the articulating frame  304  raise frame  304 , the bars  306  lift the surface cover  303 , rather than poking through. By tacking the surface cover  303  to the circuit board  302  at the key centers, a concave keycap depression effect  307  will be created when the frame raises. This allows a users fingers to be guided toward the center of each key, much like a conventional keyboard. Additionally, because there are no holes in the surface cover  303 , there is likely to be less accumulation of dirt and grime on the surface. Obviously, such an arrangement requires a more supple cover material than the rigid Lexan (polycarbonate) sheets often used as touchpad surfaces, but a variety of such materials are well known to those skilled in the art. 
     Rigid Frame Under Key Edges with Compressible Key Centers 
     Yet another embodiment may extends the covered key edge bars and key center depressions while dispensing with the mechanical complexity of frame articulation. Such an embodiment is illustrated in  FIG. 9 . The surface keyboard  400  comprises the familiar layers of an enclosure base (not shown), sensing circuit board  402  (with electrodes  402   a ), and surface cover  403 . The surface cover sits atop a frame including a fixed network of hard key-edge ridges  404 , which are preferably raised about 0.5-1 mm above the sensing circuit board  402 . The gaps between the key edge ridges  404  are filled with a compliant gel or foam material  405  (or possibly even air) filling the key centers up to flush with the ridges. 
     This arrangement allows the surface cover  303  to drape substantially perfectly flat, and remain flat when under light pressure, e.g., that from a pointing or dragging operation. However, when a user presses a key center, the cover would give under their finger somewhat as the foam/gel/air material  405  is compressed, while a user pressing over a key edge would feel the hard ridge underneath. While this arrangement is electrically and mechanically simple (with no active mechanical parts), the surface cover and key filler materials must be chosen carefully to provide noticeable compression at key center yet be durable to wear. Additionally, the sandwich of surface cover and foam could become too thick for the capacitive sensors to properly detect through. To overcome these deficiencies, the surface cover  303  itself could contain flex circuitry (well known to those skilled in the art) imprinted with a suitable electrode pattern, which would dispense with the necessity of the electrode layer  402 . 
     Many variations and/or combinations of the embodiments discussed herein will be apparent to those skilled in the art. For example, as noted above, the articulating frame may be combined with the Braille-like dots to form articulating Braille-like dots. Alternatively, the fixed Braille-like dots may be combined with the articulating ridges described with reference to  FIG. 8  or with the compressible material of  FIG. 9 . It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, combinations and equivalents as fall within the true spirit and scope of the invention.