Abstract:
A method and apparatus are provided for user input to a tablet computer. The apparatus consists of movable grips with touch sensitive regions attached to the sides of a tablet computer. Both the positions of the grips and the location of touches are used to determine the input codes sent to the computer.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This non-provisional application claims priority to U.S. provisional application 61/410,357 filed on Nov. 5, 2010, which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a method of typing and pointing on a mobile computer. 
     2. Statement of the Problem 
     Typing on mobile devices is difficult. There are currently three primary approaches: requiring a horizontal surface for a keyboard such as on notebook and laptop computers, requiring a user to cradle a device in one hand while typing with the other such as on a tablet computer, or requiring a user to use thumbs while holding a device such as on a smart phone. These approaches either limit the environments where the device can be effectively used, present poor ergonomics, or slowdown input. Attempts to resolve these limitations have been tried by putting keys on the backside of a tablet computer. In these attempts, locating keys and accessing multiple rows is difficult. 
     SUMMARY OF THE SOLUTION 
     The present invention solves the above and other problems by adding grips to the sides of a tablet-like computer with touch sensitive areas positioned under thumbs on the front and side of the grips and under fingers on back of the grips. The grips either slide in and out or rock back and forth. Both the position of the grips and the location of activated touch areas are used to determine input codes sent to the attached computer. 
     Aspects 
     An aspect of the invention is how left and right grips move independently of one another and have touch sensitive areas, such as key switches. 
     Preferably, each grip has six keys on the back and two keys on the front and side. The six keys on the back are located to allow the index finger to access two keys, the middle and ring finger to access one key each, and the little finger to access two keys. The keys on the front and side are located to allow each thumb to access two keys. 
     Preferably, the grips allow for a back and forth rocking motion with multiple positions for each of the grips on either side. 
     Alternatively, the grips allow for an in and out sliding motion with multiple positions for each of the grips on either side. 
     Preferably, icons for all keys for all grip positions are displayed on the computer screen and the keys currently active based on the grips&#39; current position are highlighted on the display. 
     Another aspect of the invention is how the grips&#39; position, together with key press state, select a specific key code that is in turn communicated to the attached computer via industry standard keyboard protocols. 
     Another aspect of the invention is how the movement of the grips together with key press state can control pointing functions on the tablet computer via industry standard pointer protocols. 
     Another aspect of the invention is how keys on the grips are movable to be positioned for individual users based on hand sizes and preferences. 
     Another aspect of the invention is how the means for adding the grips to a separate tablet computer can also function as a protective case for said tablet computer. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The above and other advantages and features of the invention may be better understood from a reading of the detailed description taken in conjunction with the drawings. The same reference number represents the same element on all drawings. 
         FIG. 1  is an isometric view showing an example of how a tablet computer is connected to and placed in the key case. 
         FIG. 2  is a front view of the key case being held by a user with the grips in the middle position and thumbs over the outer keys. 
         FIG. 3  is a back view of the key case being held by a user with the grips in the middle position and the fingers over the 4 middle keys. 
         FIG. 4  is a front view of the key case with tablet computer showing the highlighted active keys when each of the left and right grips are in each of three positions. 
         FIG. 5  is a front view of the key case with tablet computer showing alternate key icons for the right grip when the left grip inner thumb switch is pressed and the left grip is in each of three positions. 
         FIG. 6  is a front view of the key case with tablet computer showing pointer movement related to grip movement when the right grip inner thumb switch is pressed. 
         FIG. 7  is a schematic diagram of the electronics of the device. 
         FIG. 8  is a flow chart of a method for determining which input codes to send to a tablet computer based on key states and grip positions. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1-8  and the following description depict specific exemplary embodiments of the invention to teach those skilled in the art how to make and use the best mode of the invention. For the purpose of teaching inventive principles, some conventional aspects of the invention have been simplified or omitted. Those skilled in the art will appreciate variations from these embodiments that fall within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the invention. As a result, the invention is not limited to the specific embodiments described below, but only by the claims and their equivalents. 
       FIG. 1  shows a tablet computer case  100  that is designed to accept tablet computer  101 . In addition to the normal components of a tablet computer case, case  100  has grips  110  and  120  mounted on the left and right sides of the case respectively. The grips  110  and  120  are mounted to case  100  at pivot points  111  and  121  respectively. These mounts allow grips  110  and  120  to rotate independently about these pivot points in both the clockwise and counter-clockwise direction. As drawn, both grips are able to rotate in both directions up to 10 degrees. 
       FIG. 2  shows key switches  211  and  212  mounted on the front face of grip  110  and key switches  221  and  222  mounted on the front of grip  120 . A user&#39;s left hand holds grip  110  with the thumb over switch  211 . Switch  212  is located to allow the left thumb to easily rotate to reach it without requiring any hand movement. Likewise, a user&#39;s right hand holds grip  120  and has easy access to switches  221  and  222 . 
       FIG. 3  show shows the back side of the same user holding the same computer and case in the same manner. The fingers of the left hand (shown on the right in this perspective) are over switches  312  through  315 . The index finger can rotate to access switch  311  and the little finger can rotate to access key  316  without requiring any hand movement. In a likewise manner, the fingers of a user&#39;s right hand can access switches  321  through  326 . 
     All sixteen keys are mounted in slots within which they can slide. Thus the keys on the back of the grips can be slid in and out while the keys on the front of the grips can be slid up and down. The range of motion afforded the keys allow them to be positioned to accommodate the different hand sizes of different users. 
       FIG. 4  shows an example of how the selection of icons currently associated with the keys change based on grip position. In this example, the keys of a traditional QWERTY keyboard are broken into a left and right half, rotated, mirrored and placed along the sides. The keys in the three rows are reached by moving each of the grips in one of three positions. 
       FIG. 5  shows how the displayed icons of the keys can change using grip positions and key combinations. In this example, the inner key of the left thumb selects alternate keys for the right hand. The right keys are a number set when the left grip is in the middle position, a symbol set when the top of the left grip is rotated in, and a control set when the top of left grip is rotated out. 
     The icons on the display associated with keys for the various grip positions can also change based upon the current computer context. When the computer is expecting keyboard input, the keys are assigned as discussed above. When the computer has no application running, the icons for the keys can show applications to launch. Or, when the computer is running a web browser, the keys can be associated to links on the web page. 
       FIG. 6  shows how the grip movement can be used to move a cursor on the display. In this example, holding down the inner key of the right thumb causes the device to send cursor location codes based on grip position. Rotating the top of the left grip in and out causes the cursor to move down and up respectively. Rotating the top of the right grip in and out causes the cursor to move left and right respectively. In this pointer mode, the function of the keys on the back of the grips change to mouse buttons 
       FIG. 7  shows a schematic diagram of circuit  700  which is a possible implementation for the electronics of the invention. The core of the electronics is micro-controller  701 . Micro-controller  701  is connected to computer  100  via communications channel  706 . In a preferred embodiment, channel  706  is a USB connection. Key switches  211 ,  212 , and  311  through  316  from the left grip, and  221 ,  222 , and  321  through  326  from the right grip connect directly to micro-controller  701  where they are monitored for state changes. Potentiometer  702  is connected to the left grip such that the wiper of the potentiometer moves as the grip rotates. Likewise, potentiometer  703  is connected to the right grip such that its value depends of the right grip&#39;s position. The voltage on the wiper pins of potentiometers  702  and  703  are read by analog to digital converter  705  by way of analog multiplexor  704 . 
       FIG. 8  illustrates a flow chart of process  800  running on micro-controller  701  to monitor grip positions and switch states to determine input codes to send to computer  100 . In step  802 , micro-controller  701  determines if either grip has moved by reading potentiometers  702  and  703 . If there was a change then processing continues at step  808 , otherwise process  800  continues at step  804 . In step  804 , micro-controller  701  determines if there has been a change in the state of any of the keys. If there is no change then processing begins again at step  802 , otherwise process  800  continues at step  806  where an input code based on the current position of the grips and the changed key state is determined and sent to computer  100 . Process  800  then returns to step  802 . In step  808 , micro-controller  701  reads the state of the pointer key  212 . If the pointer key is pressed, processing branches to step  814 , otherwise processing continues at step  810 . In step  814 , the magnitude of the movement of the two grips is determined and pointer movement control data is calculated and sent the computer  100 . Processing then returns to step  802 . In step  810 , the grip location is measured to determine if it moved enough to select a different set of keys. If not, processing returns to step  802 . Otherwise processing continues in step  812  where a control code is sent to computer  100  instructing it to highlight the newly active set of icons. Processing then returns to step  802 . 
     Although specific embodiments were described herein, the scope of the invention is not limited to those specific embodiments. The scope of the invention is defined by the following claims and any equivalents therein.