Abstract:
Graphic User Interface for Data Processing Device A handheld data processing device ( 82 ) has a touch-sensitive display screen ( 84 ) and interface means for generating a graphic user interface (GUI) on the screen, the GUI having one or more image elements ( 88, 92, 94, 96, 98, 100, 102 ), each representing an input. The screen ( 84 ) generates a control signal corresponding to an input in response to a portion of the screen on which an image element ( 88, 92, 94, 96, 98, 100, 102 ) representing said input is displayed being touched by a user of the device. The device has processing means for processing the control signal. The interface means is operable to locate the image elements ( 88, 92, 94, 96, 98, 100, 102 ) on an accessible portion of the screen ( 84 ) so that in use the image elements are within reach of a digit ( 90 ) of a hand in which the device is held. The image elements may, for example, be located in a fan in a corner of the screen, or in linear fashion along the edges of the screen.

Description:
FIELD OF THE INVENTION 
   This invention relates to a handheld data processing device having a touch-sensitive display screen and interface means for generating a graphic user interface (GUI) on the screen, the GUI having an image element located such that the element may be touched by a thumb or finger of a hand in which the device is held so as to enter a command or an item of data, and relates also to a computer program executable by a handheld data processing device to generate such a GUI. 
   BACKGROUND TO THE INVENTION 
   A handheld data processing device such as a mobile telephone or personal digital assistant (PDA) is commonly designed to enable a user thereof to operate a keypad of the device with a thumb or finger of a hand in which the device is held. 
   It is well known to provide such a device with a touch-sensitive display screen, on certain portions of which images of keys are displayed, the device being operable to perform a function associated with each key in response to the portion of the display screen on which the image of the key is displayed being touched by the user. To date, however, the device has been designed to be held in one of the user&#39;s hands, and the display screen touched by a thumb or finger of the user&#39;s other hand, or by a stylus held in the user&#39;s other hand, and the images of the keys located on the screen in accordance with the assumption that any portion of the display screen may be touched with the same ease as any other portion. 
   SUMMARY OF THE INVENTION 
   According to a first aspect of the invention there is provided a handheld data processing device having a touch-sensitive display screen to enable a user of the device to enter an input, the device comprising:
     interface means for generating a graphic user interface (GUI) on the screen, the GUI having at least one image element representing an input, and the screen being operable to generate a control signal corresponding to said input in response to a portion of the screen on which the image element is displayed being touched by the user; and   processing means responsive to generation of said control signal to process said input;   characterised in that the interface means is operable to locate the image element on an accessible portion of the screen, so that in use the image element is within reach of a digit of a hand in which the device is held.   

   In this description the input can be a command, an alphanumeric character, a selection from a menu or any other item of data, and the at least one image element can be a picture, a word or any other suitable indicium. 
   The invention therefore provides a handheld data processing device having a GUI that enables a wide range of functions to be obtained from the device in a convenient manner. It is also possible for the device to be so arranged that those functions can be obtained using only one hand. 
   Preferably the accessible portion is so positioned that in use the at least one image element is within reach of the thumb of the hand in which the device is held. 
   Preferably the GUI has a plurality of image elements representing a respective plurality of inputs, the screen being operable to generate a control signal corresponding to an input in response to a portion of the screen on which the respective image element is displayed being touched by the user, and the interface means being operable to locate the plurality of image elements on the accessible portion of the screen. 
   Preferably the interface means is operable to locate the at least one image element at, or near to, the periphery of the display screen. 
   Typically the interface means is operable to locate the at least one image element within 2 cm of the periphery of the display screen. 
   Preferably, however, the interface means is operable to determine the accessible portion of the display screen, i.e. that portion of the screen which may be reached by a digit of the hand holding the device, and to set the size and location of the at least one image element accordingly. 
   The interface means may advantageously further be operable to determine whether for a particular user the accessible portion of the screen is larger than average, and accordingly to increase the area of the at least one image element, or where the graphic user interface has a plurality of image elements, to introduce or increase gaps between the elements, to facilitate operation of the device by a user with hands that are larger than average. 
   The interface means may advantageously be operable to locate the at least one image element in a first location to suit a left-handed user, or in a second location to suit a right-handed user. 
   Preferably the interface means is operable, in response to the portion of the screen on which a first image element is displayed being touched by the user, to display a second image element on the accessible portion of the screen. 
   The second image element may advantageously replace the first image element. 
   The interface means may advantageously further be operable to cause a label associated with the at least one image element to be displayed on a portion of the display screen outside the accessible portion. This enables a large amount of information relating to an input to be displayed on the screen of the device, without increasing the area of the at least one image element and, therefore, without reducing the number of inputs available in the accessible portion of the screen. 
   Preferably the interface means is operable to associate said label with the at least one image element by means of a lead line. 
   The device may advantageously further comprise input means, for example in the form of a push-button, the input means being operable to generate a control signal and the interface means being operable in response to said control signal to display on the portion of the screen on which the at least one image element representing a first input was displayed an image element representing a second input. 
   The interface means may advantageously be operable to cause a first image element representing a default input and a shifted input, and a second image element representing a “shift” input, to be displayed on the screen, the screen being operable to generate a control signal corresponding to the default input in response to the portion of the screen on which the first image element is displayed being touched, and being further operable to generate a control signal corresponding to the shifted input in response to the portions of the screen on which the first and second image elements are displayed being touched at the same time. 
   Alternatively, or in addition, the interface means may advantageously be operable to cause a first image element representing a default input, and a second image element representing a “shift lock” input, to be displayed on the screen, the screen being operable to generate a control signal corresponding to the “shift lock” input in response to the portion of the screen on which the second image element is displayed being touched, the interface means being responsive to the control signal corresponding to the “shift lock” input to cause a third image element representing a shifted input to be displayed on the screen, and the screen being operable to generate a control signal corresponding to the shifted input in response to the portion of the screen on which the third image element is displayed being touched. 
   Preferably the interface means is responsive to the control signal corresponding to the “shift lock” input to cause the third image element to be displayed on the screen instead of the first image element. 
   The interface means may advantageously be responsive to a further control signal corresponding to the “shift lock” input to cause the third image element to be erased from the screen. 
   Alternatively the interface means may advantageously be responsive to the control signal corresponding to the shifted input to cause the third image element to be erased from the screen. 
   In either of the aforementioned cases, the interface means is preferably operable also to cause the first image element to be displayed in place of the erased third image element. 
   The display screen may advantageously be operable to generate a first control signal in response to the user touching a portion of the screen in which an image element representing an input is displayed, and a second control signal in response to the user removing his digit from the display screen. 
   Preferably the processing means is operable to process the input only in response to generation of the first control signal followed by the second control signal. 
   Preferably the interface means is operable in response to said first control signal to display on a portion of the screen outside the accessible portion an image representing the input, and to remove said image in response to the processing means processing the input. 
   In this way the device can provide an indication of which image element is being touched by the user&#39;s digit, helping the user to avoid entering erroneous inputs, since the image element, and perhaps neighbouring image elements, may be wholly or partially obscured by the digit. 
   In preferred embodiments of the invention the touch-sensitive display screen is generally rectangular. 
   In a first embodiment the interface means is preferably operable to cause a first plurality of image elements to be displayed along a first edge of the screen such that they may be touched by the thumb of a first hand in which the device is held. 
   Preferably the interface means is further operable to cause a second plurality of image elements to be displayed along a second edge of the screen such that they may be touched by the thumb of a second hand in which the device is held. 
   The interface means may advantageously be operable to locate the first and second pluralities of image elements along opposite edges of the display screen, and preferably along the left and right edges of the screen such that the elements may be activated by the thumbs of a user&#39;s left and right hands, respectively, in which the device is held. 
   The first and/or second plurality of image elements may advantageously include an element representing a “more” input and elements representing a selection of inputs from a plurality of available inputs, the display screen being operable to generate a control signal to cause the selection of inputs to change in response to the portion of the screen on which the image element representing the “more” input is displayed being touched by the user. 
   Preferably the first and/or second plurality of image elements includes elements representing “scroll up” and “scroll down” inputs and a vertical list of elements representing a selection from a list of available inputs, the screen being operable to generate control signals to cause the vertical list of elements to be replaced by a vertical list of elements representing another selection from the list of available inputs, in response to the portion of the screen on which the image element representing the “scroll up” or “scroll down” input is displayed being touched by the user, as if the list of available inputs were present beneath the device and a portion of the vertical list were visible through the vertical list of elements, and touching the portions of the screen on which the the image elements representing the “scroll up” and “scroll down” inputs are displayed caused the list to move down and up, respectively, relative to the device. 
   Preferably the image elements are representations of keys. 
   In a second embodiment the interface means is preferably operable to generate a graphic user interface having a single image element representing a “menu” input, the screen being operable to generate a control signal corresponding to the “menu” input in response to the portion of the screen on which the element representing the “menu” input is displayed being touched by the user, and the interface means being operable to display a plurality of image elements on the accessible portion of the screen in response to generation of the control signal corresponding to the “menu” input. 
   Preferably the single image element is located at a bottom corner of the display screen. 
   The interface means may advantageously be operable to display the plurality of elements in the accessible portion of the screen adjacent to the single image element. 
   Preferably the interface means is operable to display the plurality of elements in a first curve adjacent to the single image element. 
   The interface means may advantageously further be operable to display a further plurality of elements in the accessible portion of the screen in a second curve adjacent to the first curve. 
   Preferably the first and/or second plurality of elements includes elements representing “scroll clockwise” and “scroll anticlockwise” inputs and a sector of elements arranged as a sector of a ring and representing a selection from a list of available inputs, the display screen being operable to generate control signals to cause the sector of elements to be replaced by a sector of elements representing another selection from the list of available inputs, in response to the portion of the screen on which the element representing the “scroll clockwise” or “scroll anticlockwise” input is displayed being touched, as if a virtual ring of inputs were present beneath the device and a sector of the virtual ring were visible through the sector of elements, and touching the portions of the screen on which the elements representing the “scroll clockwise” and “scroll anticlockwise” inputs are displayed caused the virtual ring to rotate anticlockwise and clockwise, respectively, relative to the device. 
   Preferably the image elements are representations of keys. 
   According to a second aspect of the invention there is provided a computer program for execution by a handheld data processing device having a touch-sensitive display screen, interface means for generating a GUI and processing means, the program being executable by the processing means to cause the interface means to generate a GUI having at least one image element representing an input, and to process a control signal corresponding to the input generated by the screen in response to the portion of the screen on which the at least one image element is displayed being touched, characterised in that the program is executable by the processing means to cause the interface means to locate the at least one image element on an accessible portion of the screen such that the element may be touched by a digit of a hand in which the device is held. 
   Preferably the computer program is further executable by the interface means to determine the accessible portion of the display screen, and to set the size and location of the at least one image element accordingly. 

   
     The invention will now be described in greater detail by way of illustrative examples and with reference to the accompanying drawings, in which: 
       FIG. 1  is a plan view of a first embodiment of a personal digital assistant (PDA) in accordance with the first aspect of the invention; 
       FIGS. 2 to 4  are plan views of the PDA of  FIG. 1  showing different states of the GUI; 
       FIG. 5  is a plan view of a further embodiment of a PDA in accordance with the first aspect of the invention; and 
       FIGS. 6 to 10  are plan views of the PDA of  FIG. 5  showing different states of the GUI. 
   

   DETAILED DESCRIPTION OF EMBODIMENTS 
   The personal digital assistant (PDA)  10  of  FIG. 1  is a first embodiment of the invention, having a touch-sensitive display screen  12  and four push-buttons, including a shift push-button  14 . The PDA has a memory and a microprocessor, neither of which is shown, and the structure and operation of which are well understood by those skilled in the art. The memory contains a first graphic user interface (GUI) program executable by the microprocessor to generate a GUI on the display screen  12 . 
   In  FIG. 1  the GUI comprises image elements in the form of representations of keys. Keys  16  to  30  are displayed along the left edge of the screen, and key  32  at the lower right edge of the screen. Keys  16  and  30  are “scroll up” and “scroll down” keys respectively, keys  18  to  28  are master menu keys, and key  32  is a shift key operable to change the functions associated with the master menu keys. 
     FIG. 1  also shows the thumb  34  of a left hand that is holding the PDA. 
   Each of the “scroll up”, “scroll down” and shift keys  16 ,  30  and  32  is operated by touching the portion of the screen on which the key is displayed with the thumb  34 . Each of the master menu keys  18  to  28 , on the other hand, is operated by touching the portion of the screen on which the key is displayed with the thumb  34  and then removing said thumb from the screen. In  FIG. 1  the thumb  34  is operating the “scroll down” key  30 . 
   In a further embodiment of the invention, not shown in the drawing figures, the shift key is displayed at the left edge of the screen with the master menu, “scroll up” and “scroll down” keys so as to facilitate one-handed operation of the PDA. 
   In  FIG. 2  master menu keys  24  to  28  are displayed towards the top of the screen  12  as a result of the operation of the “scroll down” key  30 , replacing master menu keys  18  to  22 . New master menu keys  36  to  40  are displayed along the left edge of the screen  12 . 
   The thumb  34  is touching the master menu key  36 . While the thumb remains on the key  36 , a representation of key  36  is displayed in a window  42  at the upper right corner of the screen. If the thumb were to be slid onto either of neighbouring keys  28  or  38 , a representation of the respective key would be displayed in the window  42 . The key represented in the window  42  is operated when the thumb  34  is removed from the screen. The user of the PDA is therefore provided with a visual indication of the location of his thumb relative to the keys, since the key he wishes to operate, and possibly also neighbouring keys, may be obscured by his thumb. 
   In  FIG. 3  the thumb  34  has been removed from the screen, thereby operating master menu key  36  and causing sub-menu keys  44  to  54  to be displayed along the left edge of the screen, replacing master menu keys  24  to  28  and  36  to  40 . Sub-menu keys  44  to  54  constitute an entire sub-menu, so the “scroll up” and “scroll down” keys  16  and  30  are unnecessary and are therefore removed from the GUI. 
     FIG. 3  shows three windows  56  to  60  in the middle portion of the screen. The windows contain explanations of the functions of sub-menu keys  46 ,  50  and  54  respectively and the association of each window with its sub-menu key is indicated by a respective lead line  62 ,  64  and  66 . The windows  56  to  60  serve to clarify the operation of the PDA whilst avoiding crowding of the accessible portion of the screen. 
   In  FIG. 4  the thumb  68  of a right hand in which the PDA is held is shown touching the portion of the screen on which the shift key  32  is displayed, causing shifted sub-menu keys  70  to  80  to be displayed along the left edge of the screen instead of sub-menu keys  44  to  54 . The shifted sub-menu keys could also have been caused to be displayed by the thumb  68  pressing the shift push-button  14 . 
   Touching the portion of the screen on which one of shifted sub-menu keys  70  to  80  is displayed operates the shifted sub-menu key, causing the microprocessor to carry out the function associated with the key, and causing sub-menu keys  44  to  54  to be displayed instead of shifted sub-menu keys  70  to  80 . The shifted sub-menu keys  70  to  80  are therefore displayed in response to the shift key  32  being operated until one of the shifted sub-menu keys is operated, whereupon the sub-menu keys  44  to  54  are displayed instead of the shifted sub-menu keys  70  to  80 . 
   In a further embodiment, not shown in the drawing figures, the shift key has a “shift lock” function. Touching the portion of the screen on which the shift key is displayed causes shifted sub-menu keys to be displayed instead of sub-menu keys. Touching the portion of the screen on which one of the shifted sub-menu keys is displayed operates the shifted sub-menu key, causing the microprocessor to carry out the function associated with the shifted sub-menu key. Touching the portion of the screen on which the shift key is displayed while the shifted sub-memu keys are displayed operates the shift key, causing the sub-menu keys to be displayed instead of the shifted sub-menu keys. The shifted sub-menu keys are therefore displayed in response to the shift key being operated until the shift key is operated again, regardless of whether any of the shifted sub-menu keys is operated. 
   The PDA  82  of  FIG. 5  is yet a further embodiment of the invention, having a touch-sensitive display screen  84 , four push-buttons, including a shift push-button  86 , and a memory and microprocessor, neither of which is shown. The PDA  82  is identical with the PDA  10  of  FIGS. 1 to 4 , except that the memory contains a second GUI program executable by the microprocessor instead of the first GUI program. 
   In  FIG. 5  the GUI of the PDA comprises a menu start key  88  in the lower left corner of the screen  84 . The menu start key  88  is operated simply by touching the portion of the screen on which the key is displayed with a thumb, rather than by touching then removing the thumb from the screen. 
   In  FIG. 6  the thumb  90  of a left hand in which the PDA is held is shown touching the menu start key  88 , causing master menu keys  92  to  102  to be displayed in an inner curve adjacent to the start menu key  88 . 
   In  FIG. 7  the thumb  90  is touching master menu key  98 , causing a representation of master menu key  98  to be displayed in a window  104  in the upper right corner of the screen. When the thumb  90  is removed from the screen the window  104  is removed from the GUI and the key  98  is operated, causing sub-menu keys  106  to  114  to be displayed in an outer curve adjacent to master menu keys  92  to  102 , as shown in  FIG. 8 . 
   Windows  116  and  118  containing explanation of the functions of sub-menu keys  106  and  110  respectively are displayed along the right edge of the screen, and the association of each window with its sub-menu key is indicated by a respective lead line  120  and  122 . 
   The shift push-button  86  is operable by the thumb  90  to cause a set of shifted master menu or shifted sub-menu keys to be displayed in the inner or outer curve, respectively, instead of the master menu keys  92  to  102  or sub-menu keys  106  to  112 , provided that such a shifted menu is available, otherwise shift push-button  86  has no effect. 
     FIG. 9  shows a slightly different mode of operation of the GUI, which occurs when a master menu or sub-menu contains more items than can be accommodated within the inner or outer curve, respectively. In the present example, the master menu contains more items than can be accommodated within the inner curve. The master menu keys  92  and  102  are replaced by “scroll anticlockwise” and “scroll clockwise” keys  124  and  126  respectively, while master menu keys  94  to  100  remain in place. 
   In  FIG. 9  the thumb  90  is shown touching the “scroll clockwise” key  126 . 
   In  FIG. 10  the master menu keys  98  and  100  are displayed adjacent to the “scroll anticlockwise” key  124 , as a result of the operation of the “scroll clockwise” key  126 , replacing the master menu keys  94  and  96 , and new master menu keys  128  and  130  are displayed adjacent to the “scroll clockwise” key  126 . 
   The GUI program contained in the memory of each embodiment of the invention is further executable to adapt the GUI to the size of the hand of the user of the PDA. The operation of the program contained in the memory of the first embodiment is as follows:
     1. the user is requested to enter whether he is left- or right-handed;   2. the user is requested to hold the PDA in both hands and to slide his left and right thumbs along the left and right sides, respectively, of the screen;   3. the PDA determines the mean distance from the left edge of the screen reached by the thumb of the user&#39;s left hand, and the mean distance from the right edge of the screen reached by the thumb of the user&#39;s right hand;   4. the PDA defines left and right accessible portions of the screen, consisting of rectangular areas at the left and right edges of the screen of the same widths as the mean distances from the left and right edges, respectively, of the screen reached by the thumbs of the user&#39;s left and right hands, respectively, and of the same length as the screen;   5. depending on the entry made by the user at step 1, the PDA determines whether the more frequently used keys should be located in the left or right accessible portion; and   6. the PDA scales the keys making up the GUI so as to fill the accessible portions of the screen.   

   The operation of the program contained in the memory of the embodiment shown in  FIGS. 5 to 10  is as follows:
     1. the user is requested to hold the PDA in the hand with which he wishes to operate the PDA, and to make a curvilinear sweeping movement with his thumb across the lower corner of the screen nearer to his thumb;   2. the PDA determines the mean distance from the lower corner of the screen nearer to the user&#39;s thumb reached by the thumb;   3. the PDA defines an accessible portion of the screen, consisting of a quadrant of a circle having a radius equal to the mean distance reached by the thumb and centred on the lower corner of the screen nearer to the thumb;   4. the PDA scales the keys making up the GUI so as to fill the accessible portion of the screen.   

   It will be apparent that the above description relates only to four embodiments of the invention, and that the invention encompasses other embodiments as defined by the foregoing summary of the invention.