Abstract:
In one embodiment, the transmitters and detectors for an integrated optical touch panel (OTP) are mounted at right angles to the surface of the OTP. The transmitters and detectors are contained on a substrate which is an extension of the substrate containing the touch panel display itself. The sides of the substrate containing the transmitters and detectors are folded upward so that the transmitters and detectors are positioned above the plane of the substrate containing the display.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     Portable personal devices, such as mobile telephone handsets and PDAs etc., are becoming smaller. These devices typically use integrated optical touch panels (OTP) functioning with icons and virtual keypads thereby saving space by eliminating the mechanical keypad.  
         [0002]     The transceivers of conventional OTPs are made-up of transmitters (typically Light Emitting Diodes or Laser Diodes) and detectors (typically Photo Diodes or PIN Diodes) operating in conjunction with a display device (typically a liquid crystal display (LCD)). Since the signals (light, etc.) from the transmitters to the detectors must pass above the surface of the display, the transceiver elements (transmitters and detectors) are mounted above the plane of the display. This, then, requires the transceiver elements to be mounted on risers that are at right angles to the plane of the display. Presently, manufacturing processes require separately constructed risers that are then attached to the sides of the display. This construction is costly, from both the material and building time standpoints. Also alignment of the transmitters with the detectors and with the display surface presents problems.  
       SUMMARY  
       [0003]     In one embodiment, the transmitters and detectors for an integrated optical touch panel (OTP) are mounted at right angles to the surface of the OTP. The transmitters and detectors are contained on a substrate which is an extension of the substrate containing the touch panel display itself. The sides of the substrate containing the transmitters and detectors are folded upward so that the transmitters and detectors are positioned above the plane of the substrate containing the display.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0004]     For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which:  
         [0005]      FIG. 1  shows an exploded perspective view of an optical touch panel employing the concepts of the invention;  
         [0006]      FIG. 2  shows the sides of the optical touch panel of  FIG. 1  fully folded upward;  
         [0007]      FIG. 3  shows a cut-away side view of the optical touch panel of  FIG. 1 ;  
         [0008]     FIGS.  4  shows an optical touch panel being used in an electronic device; and  
         [0009]      FIG. 5  shows one embodiment of a prior art optical touch panel. 
     
    
     DETAILED DESCRIPTION  
       [0010]      FIG. 1  shows a perspective view of an optical touch panel (OTP)  10  employing the concepts of the invention. Sides  12 - 1 ,  12 - 2 ,  12 - 3 , and  12 - 4  are shown as they are initially constructed prior to being folded upward around display  31 . Display  31 , which can be a LCD or any other display type, is shown exploded upward so as to expose optional stiffener  17  and controller  18 . Display  31  has thereon a plurality of logos, or keys, or text (soft buttons), and during operation the user&#39;s finger (or a stylus) would select the desired pattern and “press” on the display. The finger would then interrupt two light beams ( 13 ,  14 ) thereby yielding the position of the touch. Stiffener  17  is used as an aide to bending sides  12 - 1  through  12 - 4  which are bent along broken line  101 . Mounted on sides  12 - 3  and  12 - 4  are light sources, such as LEDs  13 , while mounted on opposing sides  12 - 1  and  12 - 2 , respectively, are optical detectors, such as photo detectors  14 . Mounted beneath bottom surface  102  of device  10  can be, for example, controller  18  which controls display  31  and/or the LCDs and detectors. This controller could connect to display  31  via cable  21 , shown in  FIG. 2 , that extends through slot  16 , if desired.  
         [0011]      FIG. 2  shows sides  12 - 1 ,  12 - 2 ,  12 - 3 , and  12 - 4  folded completely up around LCD  31 . Optical signals from a LED mounted or side wall  12 - 3  impacts a detector mounted on opposite side wall  12 - 1  while optical signals from a LED on side wall  12 - 4  impacts detectors on side wall  12 - 2 . These optical signals travel above the surface of Led  31  and when broken (by a finger or stylus) serve to determine the position of a touch as is well-known.  
         [0012]     Sides  12 - 1  to  12 - 4  upon which the transmitters and detectors are mounted can be aligned by the original artwork patterning of substrate  102  to achieve accurate transceiving. The vertical position can be maintained by sandwiching between internal walls of the casing (shown in  FIGS. 4A and 4B ) and LCD sides, and with this positioning can be further stabilized with adhesive after assembly into the actual mobile device.  
         [0013]     Some of the advantages of this arrangement are that all of the components can be surface mounted at one time on a single flex circuit, and the assembly can be handled by a standard doubled sided flexible circuit board assembly line. By using flex circuits thinner and more flexible devices can be achieved. In addition, flexible circuits yield higher solder joint reliability than does the existing rigid-flex process.  
         [0014]      FIG. 3  shows a cut-away side view of OTP  10  with LCD controller  18  mounted below LCD  31 . OTP controller  32  can also be mounted below LCD  31 , if desired. OTP controller  32  is connected to LEDs  13  and photo diodes  14  by wires (not shown). Note that the distance ‘h’ from the bottom of the assembly to the top of LCD  3  is the thickness of LCD  31  plus approximately 0.3 mm, which is the thickness of the substrate. This dimension will vary depending on the application. In one embodiment the height of the device is 1.2 mm above the dimension ‘h’ leaving a gap between the top surface of LCD  31  and the bottom of the LCDs. Note that the dimensions shown are for illustration purposes only and any set of dimensions can be used. The dimensions shown are for a typical mobile phone and could be larger or smaller for other applications, such as PDAs, pagers, and the like.  
         [0015]      FIG. 4  shows optical touch panel  10  within device  40 . Device  40 , in the embodiment, is a pager, but it could be any electronic device (such as a cell phone) having a display. Shown on touch panel  10  are icons  41  appearing on surface  31 . These icons, if desired, could be touch sensitive buttons which are changed in the well-known manner, from time to time. Not shown within housing  40  are, if desired, grooves on the inside of sidewall  401  for positioning optical touch panel  10  therein. Device  40  is shown with antenna  45 , hard buttons  44 , writing screen (or keypad)  42 , and buttons  43 . As consumer devices become smaller the likelihood that optical touch panel  10  would perform both keypad and display functions is increased. If used as a keypad, an image of a keypad would be created on the screen.  
         [0016]      FIG. 5  shows one embodiment of the prior art in which discrete risers  51  are mounted to substrate  54 . In this embodiment LED  53  and photo diode  52  are mounted to the rigid risers and the optical signals follow path  501 .  
         [0017]     Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.