Abstract:
A touch panel device includes a screen that has a plurality of display areas in a first layer, and a plurality of touch areas in a second layer. The second layer lies over the first layer. One touch area is superposed over one display area. The touch area is generally larger than the display area. A position of each touch area is slightly offset from the corresponding display area, depending upon a relative positional relationship between the touch panel device and a user of the touch panel device. The offsetting may be determined based on ergonomics in order to effectively. prevent an erroneous operation of a user to the touch panel device. The user is a vehicle driver if the touch panel device is used in a car navigation machine.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a touch panel device to be used as a display/input device for an electronic device such as a car navigation apparatus.  
           [0003]    2. Description of the Related Art  
           [0004]    In recent times, various electronic devices, such as an ATM and a car navigation apparatus, are equipped with a panel device which can permit a panel (or screen) to be used for data/information display and data/information entry. This type of panel device is usually referred to as “touch panel device.” Use of the touch panel device is particularly advantageous to a car navigation apparatus because a large amount of data/information should be displayed and a large amount of data/information should be input into the display panel but the size of the display panel screen is relatively small. Here, the term “data/information” includes any numbers, letters, images, signs and moving picture which can be displayed on the screen.  
           [0005]    In general, a touch panel includes a display layer and a touch sensor layer laminated over the display layer. The touch sensor layer includes transparent resistance layers and electrodes. The display layer is, for example, an LCD or an organic electroluminescent (EL) display. Data/information entry buttons or icons (referred to as “operation buttons”) are displayed on the display layer. An area used to display each data/information entry button is called a “displayarea.” Thus, a plurality of display areas are usually defined on the display layer. If the touch sensor layer is a pressure-sensitive resistance-embedded layer (resistance film type), the touch sensor layer includes two transparent resistance layers facing each other. Each transparent resistance layer is made of a glass sheet or plastic film on which an ITO (Indium Tin Oxide) is deposited.  
           [0006]    The principle of operation of the touch panel device will be described briefly. When a user presses one of the operation buttons displayed on the display layer via the touch sensor layer with his finger, a pressure applied on the button changes an electric resistance in the touch sensor layer at the position corresponding to the pressed button. A controller of the touch panel device detects the pressed position (touched area) on the touch sensor layer when the resistance changes in the touch sensor layer. The controller then determines the relationship between the touched position and the location of the pressed button so as to determine which button is pressed.  
           [0007]    [0007]FIG. 1 of the accompanying drawings illustrates a configuration of a display screen of a conventional touch panel device used in a car navigation apparatus. In this drawing, reference numeral  10  designates the display screen of the touch panel device. Each solid-line rectangle  11  designates a display area on the display layer of the touch panel device. The display areas  11  show selectable operations (menu) of the car navigation apparatus. Each broken-line rectangle  12  designates a touch area on the touch sensor layer. The touch area  12  is larger than the display area  11 . The touch area  12  concentrically overlaps the corresponding display area  11 . corresponding to the display area of the display layer. When a user presses a certain touch area  12  with his finger, the controller of the touch panel device determines that the operation button displayed in the corresponding display area  11  is pressed. The solid line rectangle for the display area  11  is visible to the user, but the broken line rectangle for the touch area  12  is not visible.  
           [0008]    The position and size of each of the display areas  11  and touch areas  12  of the touch panel device can be arbitrarily determined by software control of the touch panel device. The touch panel device can present a plurality of choice or menu screens on the single display screen. The user can touch and select a desired item from a menu of items.  
           [0009]    The position and the size of the display area  11  may be identical to those of the corresponding touch area  12 . Generally, however, the touch area  12  is larger than the display area  12 , as shown in FIG. 1. This is to ensure a touching operation made by a user is properly sensed by the touch panel device even if the user touches slightly outside the display area  11 .  
           [0010]    In practice, when a user intends to press the touch area  12  on the touch panel  10  with his finger, the user&#39;s finger sometimes touches not only the touch area  12  but also another area of the display screen, because fingers have various shapes, nails sometimes protrude from the fingers, and the approach direction of the finger to the touch panel affects the contact between the finger and the touch panel. As shown in FIG. 2 of the accompanying drawings, for example, if a user&#39;s finger  13  having a relatively long nail  14  presses the point A in the display area  11 , the user may also unintentionally touch the point B on the touch panel with his nail  14  at the same time.  
           [0011]    If the touch panel device is a pressure-sensitive resistance-embedded panel, the controller of the touch panel device generally utilizes an algorithm to determine a middle point of two points simultaneously touched on the panel screen  10 . In case of FIG. 2, the controller of the touch panel device considers that the middle point C between the points A and B is pressed if the points A and B are pressed at the same time. As seen in FIG. 2, the point C is outside the touch area  12 . The periphery of the touch area  12  defines an outer boundary of the effective touching range. Thus, a desired operation is not triggered although the user believes that the user has pressed the intended display area  11 . In fact, the finger  13  presses the point A in the touch area  12 , but the touch panel device does not operate.  
           [0012]    To prevent such inconveniences, each touch area  12  may be simply expanded. However, if the larger touch areas  12  are used, the number of menu boxes  11  is reduced. In addition, the spacing between the adjacent touch areas  12  becomes small, so that the user may touch an unintended touch area  12 , i.e., the possibility of incorrect operations increases.  
         SUMMARY OF THE INVENTION  
         [0013]    An object of the present invention is to provide a touch panel device with improved operability, which can reduce the possibility of incorrect operations.  
           [0014]    According to one aspect of the present invention, there is provided a touch panel device for an electronic device, comprising: a touch panel screen including a plurality of display areas and a plurality of touch areas such that each display area is associated with each touch area, each display area displaying data and information; a pressure detector for detecting a pressure applied to each of the touch areas to generate a detection signal representing the applied pressure; a signal generator for generating an operation command based on the detection signal, the operation command being used to control the electronic device and/or the touch panel device; and a relative relation adjuster for adjusting a relative relation between the display area(s) and the associated touch area(s) in terms of at least one of positional relationship and size relationship between the display area(s) and the associated touch area(s) in accordance with a predetermined condition.  
           [0015]    Since the relative positional relationship and/or size relationship between the display area(s) and the touch areas(s) is adjusted, the touch panel device can improve operability and reduce the possibility of incorrect operations.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1 shows a touch panel screen of a conventional touch panel device.  
         [0017]    [0017]FIG. 2 shows a surface of the touch panel screen when a user presses the touch panel screen with a finger and a nail.  
         [0018]    [0018]FIG. 3 is a block diagram of a touch panel device according to one embodiment of the present invention.  
         [0019]    [0019]FIG. 4 illustrates a schematic cross sectional view of the touch panel screen shown in FIG. 3.  
         [0020]    [0020]FIG. 5 illustrates an exploded diagram of a touch switch part shown in FIG. 4.  
         [0021]    [0021]FIG. 6 illustrates one example of a touch panel screen of the touch panel device according to the present invention.  
         [0022]    [0022]FIG. 7 illustrates a plan view of the touch panel device mounted in a right-hand drive vehicle.  
         [0023]    [0023]FIG. 7A illustrates an enlarged diagram of an area  7 A in FIG. 7.  
         [0024]    [0024]FIG. 8 shows another example of the touch panel screen of the touch panel device according to the present invention.  
         [0025]    [0025]FIG. 9 shows a plan view of the touch panel device mounted in a left-hand drive vehicle.  
         [0026]    [0026]FIG. 9A illustrates an enlarged view of an area  9 A in FIG. 9.  
         [0027]    [0027]FIG. 10 is a flowchart used to determine a relative positional relationship between display areas and touch areas on the touch panel screen. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0028]    A touch panel device according to one embodiment of the present invention will be described with reference to the accompanying drawings.  
         [0029]    Referring to FIG. 3, the touch panel device  18  is used in an electronic device for an automobile such as a car navigation device and a car stereo. The touch panel device  18  may be used in any device on a vehicle, as long as a user can see and reach a display screen of the touch panel device  18  to operate the touch panel device  18 . Therefore, the block diagram of FIG. 3 illustrates only parts of the touch panel device  18 , and other parts of the electronic device are not illustrated. The touch panel device  18  includes a touch panel  20 , a display control circuit  40 , a main control unit  30 , a display memory  60 , a system memory  50  and an arrangement command entry unit  70 .  
         [0030]    The touch panel  20  includes a display part  23  having an LCD layer or an organic EL display layer, and a touch switch part  24  having a touch sensor layer. The touch switch part  24  is provided on top of the display part  23 . The main controller  30  is connected to the touch switch part  24 , and the display control circuit  40  is connected to the display part  23 . The controller  30  is also connected to the display control circuit  40 . The display memory  60  and the system memory  50  are connected to the display controller  40 . The arrangement command input unit  70  is connected to the main controller  30 .  
         [0031]    Referring to FIG. 4, the structure of the touch panel  20  is schematically shown in the cross sectional view. The display part  23  includes a display circuit of the active matrix type, and a driver circuit for the display circuit. The display circuit has, for example, organic EL elements as light-emitting elements. The display part  23  displays a certain menu screen in response to a control signal provided from the display controller  40  (FIG. 3). The menu screen presents a plurality of operation buttons.  
         [0032]    In this embodiment, the touch panel  20  includes a touch sensor of the pressure-sensitive, resistance-embedded type (a resistance film type), which is the most popular touch sensor. Thus, the touch switch part  24 , as shown in FIG. 4, includes two transparent resistance layers, i.e., an upper resistance layer  24   a  and a lower resistance layer  24   b . The upper and lower resistance layers  24   a  and  24   b  are arranged facing each other via an intermediate layer (insulation layer)  24   c  in a direction perpendicular to the screen surface of the touch panel. The resistance layer  24   a / 24   b  is, for example, a glass sheet or a macromolecular film having an ITO (Indium-tin oxide) deposited thereon.  
         [0033]    The principle of operation of the touch switch part  24  will be described with reference to FIG. 5. The upper resistance layer  24   a  has a pair of upper electrodes X 1  and X 2 , and the lower resistance layer  24   b  has a pair of lower electrodes Y 1  and Y 2 . The direction between the upper electrodes X 1  and X 2  is referred to as the X-axis direction in FIG. 5. When a voltage is applied between the upper electrodes X 1  and X 2 , a potential gradient is produced in the X-axis direction between the electrodes X 1  and X 2  on the upper resistance layer  24   a . Since the resistance value of the upper resistance layer  24   a  is uniform, the potential gradient has a generally constant inclination in the X-axis direction. When the point A on the upper resistance layer  24   a  is pressed by a user&#39;s finger  13 , the upper resistance layer  24   a  is forced to contact the lower resistance layer  24   b  at the pressed position A. Then, the electric potential at the point A on the upper resistance layer  24   a  is transferred to the lower resistance layer  24   b , and the same voltage value as the point A is detected between the electrodes Y 1  and Y 2  of the lower resistance layer  24   b . The main controller  30  (FIG. 3) includes an analog-digital converter and converts the detected electric potential to a digital value. The main controller  30  calculates the position of the point A in the X-axis direction on the upper resistance layer  24   a  from the detected (digitized) electric potential by utilizing the fact that the potential gradient is constant.  
         [0034]    The position A in the Y-axis direction is determined in a similar manner. Specifically, an electric potential is applied between the lower electrodes Y 1  and Y 2 , the electric potential at the position A is detected between the upper electrodes X 1  and X 2 , and the main controller  30  determines the position of the point A in the Y-axis direction. After that, the controller  30  determines the coordinate value of the pressed point A on the touch panel from the calculated positions in the of the X-axis and Y-axis directions.  
         [0035]    The main controller  30  includes a microcomputer (hereinafter referred to as “μCPU”) and peripheral circuitry, and controls the entire operation of the touch panel device  18 .  
         [0036]    The display controller  40  controls a luminescent display circuit of the display section  23 , and comprises another μCPU dedicated for display control, an address control circuit for the luminescent display circuit, and peripheral circuitry. It should be noted that the present invention is not limited to the configuration shown in FIG. 3. For instance, the display controller  40  may be included in the main controller  30 .  
         [0037]    The system memory  50  comprises memory elements such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and peripheral circuitry. The ROM in the system memory  50  stores a main program, which controls an operation of the touch panel device  18 , and subprograms. The μCPUs of the main controller  30  and the display controller  40  respectively perform control operations by executing the programs step-by-step in synchronization with respective clocks. The RAM temporarily stores contents of registers and flags during execution of the programs.  
         [0038]    The display memory  60  is also a memory circuit comprising memory devices such as a ROM and a RAM, and peripheral circuitry. In the ROM of the display memory  60 , various menu screens that can be displayed on the touch panel  20  are stored in the form of pixel data. The display controller  40  selects one menu-screen from a plurality of menu screens stored in the display memory  60 , in accordance with a command from the controller  30 , and then displays the menu screen on the display section  23  in the touch panel  20 .  
         [0039]    The arrangement command input part  70  includes data/information entry buttons, keys or the like, such as numeric and function keys, provided on a console of the vehicle electronic device (e.g., a car navigation apparatus or a car stereo). A user can determine (change) the arrangement of the display areas and the touch areas on the touch panel  20  using the arrangement command input part  70 .  
         [0040]    It should be noted that the present invention is not limited to the above described configuration. For example, the touch switch part  24  of the touch panel  20  may also be used as the arrangement command entry unit  70 . Further, a reader for a portable recording medium, such as a memory card and a memory stick, may be utilized as the arrangement command entry unit  70  so as to make it possible to read arrangement data/information from the memory card or stick carried by the user.  
         [0041]    Now, the operation of the touch panel device  18  will be described.  
         [0042]    One of the features of the touch panel device  18  is offsetting of the touch areas from the display areas (or vice versa). That is, the center of each display area is deviated (shifted) from the center of the corresponding touch area.  
         [0043]    [0043]FIG. 6 shows one example of the display screen of the touch panel device  18 . Each solid-line box  21  designates the display area and each broken-line box  22  designates the touch area. Certain data/information is displayed in each display area  21 . The solid line rectangle for the display area  21  is visible to the user, but the broken line rectangle for the touch area  22  is not visible.  
         [0044]    As seen in FIG. 6, each touch area  22  is offset towards the upper left from the associated display area  21 . This arrangement of the display areas  21  and touch areas  22  is believed to be advantageous when the user is a driver of a right-hand drive vehicle, the touch panel  20  is mounted at the approximate center of a console, and the touch panel device  18  is situated on the left front of the driver. It is assumed that an elbow of the driver on a seat is positioned below the touch panel  20 .  
         [0045]    In the right-hand drive vehicle as shown in FIG. 7, the electronic device  28  such as a car navigator is usually mounted at the center of a console  26 . Thus, the touch panel device  18  of the electronic device  28  is situated on the left front side of the driver  29  above the driver&#39;s elbow. When the driver  29  operates the touch panel device  18 , the driver  29  most probably uses the index finger (fore finger) or the middle finger of the left hand as the panel pressing finger. The driver  29  tries to reach the touch panel device  18  by extending the left arm  29 L such that the finger  13 L moves from the lower right side of the touch panel device  18  towards a desired display area  21  on the touch panel screen. In this case, as shown in the enlarged view (FIG. 7A), an area that is most probably touched by the driver&#39;s finger  13 L is the desired display area  21  or the upper and left peripheral areas (shaded area)  27  outside the display area  21  on the touch panel  20 . This is because the finger  13 L is moving in the upper left direction. If the touch panel screen is simultaneously touched by the finger  13 L and the nail  14 L as shown in FIG. 2, it is assumed that the middle point C between the two touched points A and B falls in the shaded area  27  outside the display area  21 .  
         [0046]    Accordingly, each touch area  22  is shifted in the upper left direction relative to the display area  21  as shown in FIG. 6, such that the touch area  22  coincides with the combination of the display area  21  and the shaded area  27  (FIG. 7). Therefore, even if the driver touches the touch panel screen outside a desired button (display area)  21 , the possibility of triggering a desired operation increases, as compared with the conventional touch panel device shown in FIG. 1. In particular, even if the driver&#39;s nail  14 L is relatively long, the middle point C probably falls in the touch area  22  so that an intended operation is started. The touch area  22  of the touch panel device  18  has the same size as the touch area  12  shown in FIG. 1. Therefore, the touch panel  20  can display the same number of items on the screen as the touch panel device of FIG. 1.  
         [0047]    Another arrangement of the display areas  21  and touch areas  22  is shown in FIG. 8.  
         [0048]    In FIG. 8, each touch area  22  is offset towards the upper right relative to the corresponding display area  21 . This arrangement of the display areas  21  and touch areas  22  is considered to be advantageous when the vehicle is a left-hand drive vehicle as shown in FIG. 9. The touch panel device  18  is mounted at the center of the console  26 . When the driver  29  is seated, the touch panel device is located at the right front of the driver  29 . The touch panel device  18  is above the elbow of the seated driver.  
         [0049]    When the driver  29  operates the electronic device  28 , the driver  29  generally uses the index finger or the middle finger  13 R of his right hand to touch the touch panel device  18 . When the driver  29  tries to touch the touch panel screen  20 , the finger  13 R moves from the lower left side of the touch panel device  18  towards the touch panel device  18 . In this case, as shown in FIG. 9A, it is assumed that the display area  21  and the shaded area  27 ′ are most probably touched by the driver  29  when the driver intends to touch the display. area  21 . This assumption is established based on human engineering. The shaded area  27 ′ extends in the upper and right peripheral areas of the display area  21 . If the touch panel screen is simultaneously touched by the finger  13 R and the nail  14 R as shown in FIG. 2, the middle point C between the two touched points A and B falls in the shaded area  27 ′.  
         [0050]    Accordingly, as shown in FIG. 8, if the touch area  22  is offset towards the upper right direction relative to the display area  21  such that the touch area  22  coincides with the combination of the display area  21  and the shaded area  27 ′, an erroneous operation of the driver is prevented. The same advantage as the example shown in FIG. 6 is achieved.  
         [0051]    Since the size and resolution of the display area  21  are different from the size and resolution of the touch area  22  on the touch panel  20 , the main controller  30  of the touch panel device  18  performs the matching operation. Specifically, the main controller  30  calculates the ratio of the resolution of the display layer in the display part  23  to the output resolution of the touch sensor layer in the touch switch part  24 . The main controller  30  then conforms the display area  21  with the touch area  22 , using the calculated resolution ratio. In order to maintain the relative positional relationship between each pair of display area  21  and touch area  22  on the display panel  20  during the operation of the touch panel device  18 , a process shown in FIG. 10 is performed within a common calibration process implemented in the touch panel device  18 . As shown in the flowchart of FIG. 10, the main controller  30  of the touch panel device  18  receives the information of the desired relationship between the display areas  21  and the touch areas  22  from the system memory  50  (Step S 1 ). Then, the main controller  30  determines whether the vehicle is a right-hand drive (Step S 2 ). If the vehicle is right-hand drive, the main controller  30  maintains the touch area  22  in the upper left offset position (Step S 4 ). If the vehicle is a left-hand drive (Yes at Step S 3 ), the main controller  30  maintains the touch area  22  in the upper right offset position (Step S 5 ). If the steering wheel  31  of the vehicle is located in the middle of the vehicle, the touch area  22  is not offset from the associated display area  21  (Step S 6 ), as shown in FIG. 1.  
         [0052]    The information of the desired relationship between the display areas  21  and the touch areas  22  (Step S 1 ) may be input into a nonvolatile RAM of the system memory  50  by the driver using the arrangement command entry unit  70 . Alternatively, the information may be entered by a serviceman of an automobile dealer when the vehicle is purchased, as an initial setting of the touch panel device  18 .  
         [0053]    Although the touch area  22  is offset to the upper left direction or the upper right direction in the illustrated embodiments, the present invention is not limited in this regard. Specifically, the touch area  22  can be offset in any direction (to the right, the left, the lower right, the lower left, or downwards) relative to the. associated display area  21 , depending upon the positional relationship between the touch panel device user and the touch panel device. Further, the touch areas  22  may be fixed and the display areas  21  may be shifted.  
         [0054]    In addition to or instead of the offset arrangement between the display areas  21  and the touch areas  22 , the display areas  21  and/or the touch areas  22  may be changed in size and/or shape. That is, at least either the relative positional relationship or the relative size relationship between the display areas and touch areas is adjustable in this invention. The change made to the relative relationship between the display areas and touch areas may be determined based on ergonomics.  
         [0055]    This application is based on a Japanese patent application No. 2002-153221, and the entire disclosure thereof is incorporated herein by reference.