Abstract:
Keyboard systems for interfacing with a touchscreen. The keyboard includes: a plurality of contact members formed of electrically conducting material, each of the contact members having first and second sides; and a plurality of keys. Each key has an electrically conducting key-pad unit and a resilient member, where the resilient member is adapted to maintain the key-pad unit in a spaced part relationship relative to a corresponding one of the contact members. The first side of each contact member is in constant contact with a particular portion of the touchscreen. The key-pad unit is adapted to contact the second side of a corresponding one of the contact members when pressed by a foreign object, to thereby form an electrically conducting path between the foreign object and the particular portion of the touchscreen.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to data entry keyboards, and more particularly, to tactile keyboards for touch screen. 
         [0002]    With the advancement of electronic technologies, touchscreens have become increasingly popular in the field of consumer electronics. A touchscreen is a display capable of detecting the presence and location of a touch (or stimulus) within a display area and interpreting the touch as input. The ability of a touchscreen to receive (i.e., detect and interpret) a stimulus is typically enabled through the use of a plurality of touch-sensitive sensors embedded in the touchscreen. 
         [0003]    Touch-sensitive sensors respond to a stimulus and produce a signal indicative of the stimulus&#39;s magnitude, relative position, or other characteristic attributable to the stimulus. Typical touch-sensitive sensor implementations in the field of consumer electronics include resistive sensing, capacitive sensing, infrared sensing, optical imaging and dispersive signal technology. 
         [0004]    Applications in which touchscreen applications may be used include display interfaces of computing devices, such as notebook computers, iPad™ tablet computer, personal data assistants (PDAs), and mobile phones. Other popular applications in which touchscreens have been incorporated include the user interfaces of bank automated telling machines, kitchen appliances, exercise equipment, satellite navigation devices and various other consumer electronics. 
         [0005]    Displays which offer touchscreen functionality provide substantial benefits over traditional displays. These benefits include the ability to directly interact with the content displayed on the touchscreen, rather than indirectly with a dedicated input device, such as a keyboard, keypad, mouse, or touchpad. Another benefit of a touchscreen display is the ability to receive input without requiring the presence of a dedicated input device. As consumer electronic devices (particularly mobile handsets) continue to reduce in size, the inclusion of a touchscreen provides a manufacturer the ability to further reduce the size of the device by eliminating the space required for an input terminal. In addition, by devoting the entirety of a device&#39;s surface area for use as a display rather than apportioning the surface area between a display area and an input terminal (e.g., keypad), the total display area may be increased, resulting in a superior user experience. 
         [0006]    However, in general, mobile computing devices such as cell phones, smart phones and PDAs which use touchscreens as a primary method of input may be difficult or inconvenient to use. For example, typical touchscreens lack the tactile feedback provided by pressing a tangible button or key in a physical input terminal. Accordingly, users may be uncertain whether any key was actuated at all or any key was actuated more times than intended. Thus, in order for the user to be assured that input is being received as intended, the user is required to monitor the output field on the display to verify both that a key was entered, and more specifically, that the correct key was entered as intended. 
         [0007]    Since data entry into the conventional touchscreen is simply based on the 2-D virtual keypad displayed on the monitor, the virtual keys are without depth or any feel other than the simple pressure reaction by the flat surface, and the user must therefore carefully aim to touch the desired virtual key. Unlike the conventional remote keyboard, the touchscreeen has no capability to provide tactile feedback to the user, which limits its usefulness and accuracy in use. Accordingly, it is desired to provide tactile feedback in a touch screen for matching the benefits of a mechanical keyboard. 
       SUMMARY OF THE INVENTION 
       [0008]    In one embodiment of the present disclosure, a keyboard system for interfacing with a touchscreen includes: a plurality of contact members formed of electrically conducting material, each of the contact members having first and second sides; and a plurality of keys. Each key has an electrically conducting key-pad unit and a resilient member, where the resilient member is adapted to maintain the key-pad unit in a spaced part relationship relative to the corresponding contact member. The first side of each contact member is in constant contact with a particular portion of the touchscreen. The key-pad unit is adapted to contact the second side of the corresponding contact member when pressed by a foreign object, to thereby form an electrically conducting path between the foreign object and the particular portion of the touchscreen thorough the contact members and the electrically conducting key-pad unit. 
         [0009]    In another embodiment of the present disclosure, an electronic device includes a touchscreen and a keyboard system to be mounted on the touchscreeen. The keyboard system includes: a plurality of contact members formed of electrically conducting material, each of the contact members having first and second sides; and a plurality of keys. Each key has an electrically conducting key-pad unit and a resilient member, where the resilient member is adapted to maintain the key-pad unit in a spaced part relationship relative to a corresponding one of the contact members. The first side of each contact member is in constant contact with a particular portion of the touchscreen. The key-pad unit is adapted to contact the second side of a corresponding one of the contact members when pressed by a foreign object, to thereby form an electrically conducting path between the foreign object and the particular portion of the touchscreen thorough the contact members and the electrically conducting key-pad unit. 
         [0010]    These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  shows an exploded view of a keyboard system disposed over a portion of a touchscreen in accordance with one embodiment of the present invention; 
           [0012]      FIG. 2  shows a top view of a portion of the keyboard system of  FIG. 1 ; 
           [0013]      FIG. 3A  shows a cross sectional view of the portion of the keyboard system in  FIG. 2 , taken along the line  3 - 3 ; 
           [0014]      FIG. 3B  shows a cross sectional view of the portion of the keyboard system in  FIG. 2 , illustrating the key action when a finger presses the key; 
           [0015]      FIG. 4A  shows a top view of a contact member in accordance with another embodiment of the present invention; 
           [0016]      FIG. 4B  shows a bottom view of the contact member of  FIG. 4A ; 
           [0017]      FIG. 4C  shows a bottom perspective view of the contact member of  FIG. 4A ; 
           [0018]      FIG. 4D  shows a side view of the contact member of  FIG. 4A ; 
           [0019]      FIG. 4E  shows a front view of the contact member of  FIG. 4A ; 
           [0020]      FIG. 5  shows a cross sectional view of a portion of a keyboard system having the contact member of  FIG. 4A ; 
           [0021]      FIG. 6  shows a top view of a portion of a keyboard system in accordance with yet another embodiment of the present invention; 
           [0022]      FIG. 7  shows a cross sectional view of the portion of the keyboard system in  FIG. 6 , taken along the line  7 - 7 ; and 
           [0023]      FIG. 8  shows a cross sectional view of a portion of a keyboard system in accordance with still another embodiment of the present invention; 
           [0024]      FIG. 9A  shows a top view of a portion of a keyboard system in accordance with further another embodiment of the present invention; 
           [0025]      FIG. 9B  shows a cross sectional view of the portion of the keyboard system of  FIG. 9A , taken along the line  9 - 9 ; 
           [0026]      FIG. 10  shows a cross sectional view of a portion of a keyboard system in accordance with yet further another embodiment of the present invention; 
           [0027]      FIG. 11  shows a cross sectional view of a portion of a keyboard system in accordance with another embodiment of the present invention; 
           [0028]      FIG. 12A  shows a side view of a keyboard system rotatably attached to an electronic device or device case in accordance with still further another embodiment of the present invention; 
           [0029]      FIG. 12B  shows a side view of the keyboard system of  FIG. 12A  disposed over the touchscreen of the electronic device when being used; 
           [0030]      FIG. 12C  shows a side view of the keyboard system of  FIG. 12A  retracted under the electronic device when not used; 
           [0031]      FIG. 13A  shows a perspective view of a keyboard system slidably mounted to an electronic device in accordance with another embodiment of the present invention; 
           [0032]      FIG. 13B  shows a front view of the keyboard system of  FIG. 13A  disposed over the touchscreen of the electronic device when being used; 
           [0033]      FIG. 13C  shows a front view of the keyboard system of  FIG. 13A  stowed under the electronic device when not used; and 
           [0034]      FIG. 14  shows a front view of a keyboard system slidably mounted to an electronic device in accordance with another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0035]    Referring now to  FIG. 1 , there is shown an exploded view of a keyboard system  11  to be disposed over a portion of a touchscreen  12  in accordance with one embodiment of the present invention. As depicted, a device  10  may be a conventional electronic device and includes the touchscreen  12  for displaying various digital images. The touchscreen  12  includes touch-sensitive sensors (not shown in  FIG. 1 ) embedded therein, where the sensor implementation includes capacitive sensing technology. For the purpose of illustration, the sensors in the touchscreen  12  are considered to be capacitive sensors, even though other suitable type of sensors may be used in the touchscreen  12 . 
         [0036]    The touch-sensitive sensors are responsive to a physical stimulus or contact with a foreign object, such as finger or stylus. Thus, when an image including virtual keys  14  is displayed on the touchscreen  12 , the user may input data to the device  10  by directly touching the virtual keys  14 . Since the virtual keys  14  are displayed on 2-D touchscreen, the virtual keys  14  do not have depth or any feel other than the simple pressure reaction atop the flat touchscreen  12 . Thus, the user may mount the keyboard system  11  on the touchscreen  12  so that the user can get tactile feedback when inputting data into the device  10 . 
         [0037]    The keyboard system  11  includes: a lower keyboard unit  16  having a lower panel  17  and a plurality of contact members  18  mounted in the lower panel  17 ; and an upper keyboard unit  20  having an upper panel  21  and a plurality of keys  22 . When the keyboard system  11  is mounted on the touchscreen  12 , the lower keyboard unit  16  makes a firm contact with the touchsreen surface. The lower panel  17  is formed of electrically insulating (or, equivalently, dielectric) material, such as rubber or plastic. The width and length of the lower panel  17  may be determined such that the lower keyboard unit  16  covers the entire image of the virtual keys  14 . The contact members  18  are formed of electrically conducting material, such as metal, carbon-filled rubber, carbon-filled polymer, metal-filled rubber, metal-filled polymer. Each of the contact members  18  has a substantially circular ring shape and is disposed over the corresponding virtual key when the lower keyboard unit  16  is mounted over the touchscreen  12 . The location and diameter of each contact member  18  are determined such that the character (or symbol) of the corresponding virtual key can be visible to the user through the inner hole of the contact member. 
         [0038]      FIG. 2  shows a top view of a portion of the keyboard system  11 .  FIG. 3A  shows a cross section view of the portion of the keyboard system in  FIG. 2 , taken along the line  3 - 3 . As depicted, the lower panel  17  and contact members  18  are in firm contact with the touchscreen  12  when the keyboard system  11  is mounted on the touchscreen  12 . The upper panel  21  of the upper keyboard unit  20  is in contact with the lower panel  17 . The key  22  includes: a dome  24  (or, equivalently, spring member or resilient member); a key-pad ring  26 ; and a key-pad disk  28  secured to the key-pad ring  26 . (A term key-pad unit collectively refers to the key-pad ring and key-pad disk.) The upper panel  21  may be formed of electrically insulating (or, equivalently, dielectric) material, such as silicone rubber or other elastomer. The dome  24  may be formed of a dielectric elastic material, such as silicone rubber or other elastomer, and configured to separate the key-pad ring  26  from the contact member  18  when the key-pad disk  28  is not pressed by a finger. 
         [0039]    The key-pad ring  26  is formed of an electrically conducting material, such as metal, carbon-filled rubber, carbon-filled polymer, metal-filled rubber, metal-filled polymer. The key-pad disk  28  may be formed of a transparent material, such as polycarbonate or acrylic. The upper keyboard unit  20  is arranged relative to the lower keyboard unit  16  such that the user may see the character (or symbol, say “A”) displayed on the corresponding virtual key  14  through the transparent key-pad disk  28  and the inner hole of the contact member  18 . 
         [0040]      FIG. 3B  shows a cross section view of the portion of the keyboard system in  FIG. 2 , illustrating the key action when a finger presses the key  22 . When the user presses the key  22 , more specifically the key-pad disk  28 , the dome  24  flexes and bends to make a contact between the key-pad ring  26  and the contact member  18 . Since the dome  24  is formed of elastic material, the deformed dome generates a resilient force so that the key  22  restores to its original position (as shown in  FIG. 3A ) when the user releases the key  22 . 
         [0041]    When the finger presses the key  22 , the key-pad ring  26  makes a physical contact with the contact member  18 . Thus, even though the virtual key  14  of the touchscreeen  12  is not directly activated by a user finger, the virtual key  14  is activated by bringing the indirect contact between the finger and the virtual key  14  via the key-pad ring  26 , and the contact member  18 . More specifically, the capacitance of the finger is transmitted to the virtual key  14  via the key-pad ring  26 , and the contact member  18 . Thus, key-pad ring  26  and the contact member  18  form an electrical path between the finger and virtual key  14 . 
         [0042]    While the touchscreen contact is the same as if a user had directly placed his or her finger on the touchscreen  12 , the sensation to the user has been altered since the user can now feel the sensation of physical displacement of the key-pad disk  28  as well as the key-pad displacement arrested by contact with the contact member  18 . Thus, the user receives a tactile feedback signal, while the signal has been applied to the touchscreen  12 . The keyboard system  11  is a mechanical interface for the touchscreen  12  and provides tactile feedback to the user. The key-pad disk  28  may be eliminated depending on the design implementation. 
         [0043]    As shown in  FIGS. 3A and 3B , the entire bottom surface of the contact member  18  contacts the corresponding virtual key  14 . As an alternative, the actual contact area between the contact member  18  and the virtual key  14  may be modified so that the contact can more closely simulate a finger touch.  FIGS. 4A-4E  respectively show a top view, a bottom view, a side view, a front view, and a bottom perspective view of a contact member  30  in accordance with another embodiment of the present invention. As depicted, the contact member  30  includes a protrusion (or bump)  32  that makes a direct and constant contact with the corresponding virtual key  14 .  FIG. 5  shows a cross section view of a portion of a keyboard system having the contact member  30 . As depicted, the keyboard system is similar to the system  11  (shown in  FIG. 1 ) with the difference that the contact member  32  has a protrusion. The modification of the contact area of the contact member serves to produce an input more closely representing the touch of a finger, which the device is designed to recognize. This eliminates erroneous multi-activations. The bottom surface of the protrusion  32  may be flush with the bottom surface of lower panel  33 , or may extend beyond the bottom surface of lower panel  33  to ensure a good contact with the virtual key  14 . 
         [0044]    The key  22  may have other geometrical shapes.  FIG. 6  shows a top view of a portion of a keyboard system in accordance with yet another embodiment of the present invention.  FIG. 7  shows a cross sectional view of the portion of the keyboard system in  FIG. 6 , taken along the line  7 - 7 . As depicted, the keyboard system of  FIG. 6  is similar to that of  FIG. 2 , with the difference that the key  40  has a substantially rectangular shape. The keyboard system includes: an upper panel  41 ; a dome  42  (or, equivalently, resilient or spring member); a key-pad ring  44  that has a substantially rectangular ring shape; a transparent key-pad disk  46  secured to the key-pad ring  44 ; a lower panel  48 ; and a contact member  50  that has a substantially rectangular ring shape. Since each of the components of the keyboard system shown in  FIG. 6  is similar to its counterpart of the keyboard system  11  in  FIGS. 1 ,  2 , and  3 A, the description of the keyboard system in  FIGS. 6-7  is not repeated. 
         [0045]      FIG. 8  shows a cross section view of a portion of a keyboard system in accordance with still another embodiment of the present invention. As depicted, the keyboard system in  FIG. 8  is similar to that of  FIG. 7 , with the difference that the contact member  52  has a protrusion (or equivalently, bump)  54 . The function and structure of the protrusion is similar to those of the protrusion  32  (shown in  FIGS. 4A-4E ). 
         [0046]      FIG. 9A  shows a top view of a portion of a keyboard system in accordance with further another embodiment of the present invention.  FIG. 9B  shows a cross sectional view of the portion of the keyboard system of  FIG. 9A . As depicted, the upper keyboard unit includes an upper panel  60  and a key  62 , where the key  62  includes a dome  64  (or, equivalently, resilient member or spring member) and a key-pad disk  66 . The key-pad disk  66  is formed of opaque and electrically conducting material, such as metal, carbon-filled rubber, carbon-filled polymer, metal-filled rubber, metal-filled polymer. The key-pad disk  66  may include a character (say, “A”) that matches the corresponding virtual key displayed on the touchscreen  12 . Since the lower keyboard unit  65  is similar to the lower keyboard unit  16 , the description of the lower keyboard unit is not repeated for brevity. 
         [0047]    It is noted the key-pad disk  66  may be formed of transparent and electrically conducting material, such as ITO (indium tin oxide). In this embodiment, the user may see the characters displayed on the touchscreen through the key-pad disks, and thus, the key-pad disk  66  may not include any character that matches the corresponding virtual key displayed on the touchscreen  12 . 
         [0048]      FIG. 10  shows a cross sectional view of a portion of a keyboard system in accordance with yet further another embodiment of the present invention. As depicted, the upper keyboard unit includes an upper panel  78  and a key  70 , where the key  70  includes a dome  76  (or, equivalently, resilient member or spring member) and a key-pad unit  71  having a pair of key-pad disks  72   a ,  72   b  connected by vias  74 . One of the key-pad disk  72   a  or  72   b  may be eliminated as long as vias  74  can make good contact with the finger or the contact member  73 . The vias  74  are formed of electrically conducting material, such as metal, carbon-filled rubber, carbon-filled polymer, metal-filled rubber, metal-filled polymer, and pass through the upper panel  78 . 
         [0049]    The key-pad disks  72   a ,  72   b  are formed of electrically conducting material, such as metal, carbon-filled rubber, carbon-filled polymer, metal-filled rubber, metal-filled polymer. When a finger of the user presses the key-pad disk  72   a  to thereby bring the key-pad disk  72   b  into contact with the contact member  73 , the capacitance of the finger is transmitted to the virtual key displayed on the touchscreen  12  through the upper key-pad disk  72   a , the vias  74 , the lower key-pad disk  72   b , and the contact member  73 . Since the lower keyboard unit is similar to the lower keyboard unit in  FIG. 9B , the description of the lower keyboard unit is not repeated for brevity. 
         [0050]      FIG. 11  shows a cross sectional view of a portion of a keyboard system in accordance with another embodiment of the present invention. As depicted, the upper keyboard unit includes an upper panel  96  and a key  90  where the key  90  includes a dome  94  (or, equivalently, resilient member or spring member), a key-pad disk  92 , and a key-pad ring  98 . The key-pad disk  92  is formed of transparent material, such as polycarbonate or acrylic. The key-pad disk  92  is affixed to the dome  94 . The key-pad ring  98  is formed of a thin electrically conductive material, such as metal, carbon-filled rubber, carbon-filled polymer, metal-filled rubber, metal-filled polymer. 
         [0051]    The key-pad ring  98  makes a contact with the contact member  95  when the key-pad disk  92  is pressed by a finger of the user. Upon contact, the capacitance of the finger is transmitted to the virtual key displayed on the touchscreen  12  via the key-pad ring  98  and the contact member  95 . The key-pad ring  98  may be formed on the surface of the key-pad disk  92  by various methods. For example, the key-pad ring  98  may be deposited on the key-pad disk  92  by the conventional chemical vapor deposition technique, or any other suitable vapor deposition technique. In another example, the key-pad ring  98  may be coated or printed on the key-pad disk  92 . Since the lower keyboard unit is similar to the lower keyboard unit in  FIG. 9B , the description of the lower keyboard unit is not repeated for brevity. 
         [0052]    In each of  FIGS. 2-11 , the dome and upper panel are shown to form one integral body. For example, the dome  24  and the upper panel  21  are made from one sheet of dielectric panel. However, the dome may be fabricated separately from the upper panel and affixed to the upper panel, i.e., the dome  24  may be fabricated with the key  22  and secured to the upper panel  21  subsequently. 
         [0053]    It is noted that the contact members in  FIGS. 9A-11  do not have protrusion (or bump). However, it should be apparent to those of ordinary skill that the contact member  32  (shown in  FIGS. 4A-4E ) may be used in place of the contact members shown in  FIGS. 9A-11 . It is also noted that the key-pad disks and key-pad rings shown in  FIGS. 1-11  may have a suitable geometry, such as circle, rectangle, or polygon. 
         [0054]      FIG. 12A  shows a side view of a keyboard system  101  rotatably attached to an electronic device  100  or an electronic device case (not shown in the figure) by a linkage  106  in accordance with another embodiment of the present invention. As depicted, the keyboard system  101  includes an upper keyboard unit  104  and a lower keyboard unit  102 . One end of the linkage  106  is rotatably attached to the electronic device  100  or an electronic device case (not shown in the figure) while the other end of the linkage  106  is rotatably attached to the keyboard system  101 . 
         [0055]      FIG. 12B  shows a side view of the keyboard system  101 , where the keyboard is disposed over the touchscreen of the electronic device  100 . The user can interact with the device  100  by pressing the keys  108  in the keyboard system  101 .  FIG. 12C  shows a side view of the keyboard system  101 , where the keyboard system  101  is retracted under the electronic device or an electronic device case (not shown in the figure) when the user does not use the keyboard system  101 . 
         [0056]      FIG. 13A  shows a perspective view of a keyboard system  111  slidably mounted to an electronic device  113  in accordance with another embodiment of the present invention.  FIG. 13B  shows a front view of the keyboard system  111  disposed over the touchscreen  117  of the electronic device  113  when being used.  FIG. 13C  shows a front view of the keyboard system  111  stored in a cavity  112  when not used. As depicted, the keyboard system  111  includes: an upper keyboard unit  115  having keys  116 ; and a lower keyboard unit  114 . The structures and functions of the upper and lower keyboard units  115 ,  114  are similar to those of the upper and lower keyboard units  20 ,  16 , respectively, and thus the description of the units are not repeated. 
         [0057]    The upper keyboard unit  115  and the lower keyboard unit  114  can be slidably mounted along the grooves  119  formed on the inner wall of a case  110  so that the user can use the keyboard system  111  to interact with the electronic device  113 . The case  110  may be formed of material, such as plastic, that can provide mechanical strength to hold the keyboard system  111 . The case  110  includes a cavity  112  where the keyboard system  111  can be stored when not used, as depicted in  FIG. 13C . 
         [0058]      FIG. 14  shows a front view of a keyboard system  120  slidably mounted to an electronic device  126  in accordance with another embodiment of the present invention. As depicted, the keyboard system  120  includes: an upper keyboard unit  122  having keys  123 ; and a lower keyboard unit  124 . The structures and functions of the upper and lower keyboard units  122 ,  124  are similar to those of the upper and lower keyboard units  20 ,  16 , respectively, and thus the description of the units are not repeated. 
         [0059]    The upper keyboard unit  122  includes a panel that extends over the side of the electronic device  126  and covers a portion of the bottom surface of the electronic device so that the keyboard system  120  can be slidably mounted over the touchscreen of the electronic device  126 . The keyboard system  120  can be slidably mounted under the electronic device  126  when the keyboard system  120  is not used. 
         [0060]    It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.