Abstract:
A touch panel system that sanitizes a touch panel surface includes a substrate coupled to the touch panel surface. The system further includes an impedance interface coupled to the touch panel surface and a vibration source coupled to the impedance interface. The vibration source vibrates the substrate to generate pressure waves which destroy contaminants on the touch panel surface.

Description:
FIELD OF THE INVENTION 
       [0001]    One embodiment of the present invention is directed to touch panels. More particularly, one embodiment of the present invention is directed to sanitizing a touch panel surface. 
       BACKGROUND INFORMATION 
       [0002]    Touch panels have become more and more popular as input sources for computers and other devices. A touch is sensed by a touch panel when a finger or a stylus comes into contact with the outermost surface of the touch panel. The contact is translated into x and y coordinates of the finger or stylus on the panel. Some touch panels are transparent overlays placed over a display. Other touch panels are non-transparent devices typically used to control cursor movement on a portable computer, for example, or as pen input devices for applications including writing or signature input to a computer. 
         [0003]    However, most touch panel surfaces require direct contact with the skin of the user&#39;s finger, and public touch panels such as automatic teller machines (“ATMs”) are touched by many different users. These panels provide a suitable home for bacteria, fungi, algae, and other organisms which thrive and propagate based on the availability of appropriate amounts of moisture, temperature, nutrients, and receptive surfaces. Further, as these organisms thrive, the variety of chemicals that these organisms produce are also known to affect the human user. Thus, these microorganisms, as well as their metabolic products (collectively, “contaminants”) can pose serious health risks to users ranging from minor skin irritation to more serious toxic response and disease. With the increased popularity of such touch panels, the public is becoming increasingly aware of and concerned with the presence of microorganisms on these panels and the potential consequences resulting from contact with such contaminated surfaces. 
         [0004]    Known methods for keeping touch panel surfaces clean and sanitized include wiping the screens with a liquid antiseptic solution. However, this can only be done periodically and is not a long-lasting solution since the liquid will evaporate. Other known methods include incorporating antimicrobial agents within the screen. However, these agents cannot account for the wide range of organisms that can potentially accumulate on the screen and will eventually lose their effectiveness. 
         [0005]    Based on the foregoing, there is a need for a system and method for sanitizing touch panel surfaces to effectively eliminate hazards to users. 
       SUMMARY OF THE INVENTION 
       [0006]    One embodiment of the present invention is a touch panel system that sanitizes a touch panel surface. The system includes a substrate coupled to the touch panel surface. The system further includes an impedance interface coupled to the touch panel surface and a vibration source coupled to the impedance interface. The vibration source vibrates the substrate to generate pressure waves which destroy contaminants on the touch panel surface. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a side view of a touch panel that includes a touch panel surface sanitizer in accordance with one embodiment of the present invention. 
           [0008]      FIG. 2  is a flow diagram of the functionality of one embodiment of the present invention to sanitize a touch panel surface. 
       
    
    
     DETAILED DESCRIPTION 
       [0009]    One embodiment of the present invention is a system for sanitizing a touch panel surface by generating high frequency vibrations on a substrate applied on the surface. The vibrations induce pressure waves and cavitation to destroy contaminants on the surface or mechanically separate contaminants from the surface. 
         [0010]      FIG. 1  is a side view of a touch panel  10  that includes a touch panel surface sanitizer in accordance with one embodiment of the present invention. Touch panel  10  includes a touch panel surface  20  made of glass or other material, and a liquid crystal diode (“LCD”) display  12  for displaying information that can be viewed through the transparent or semi-transparent touch panel surface  20 . In one embodiment, a gap exists between LCD display  12  and touch panel surface  20  to accommodate movement of touch panel surface  20  in the X or Y direction. Movement of touch surface  20  in the Y direction can provide, for example, a haptic or vibrotactile feedback to a user of touch panel  10 . One type of haptic feedback can be a vibration applied to touch panel surface  20  by an actuator when a user touches surface  20 . One example of such haptic feedback is disclosed in U.S. Pat. No. 6,429,846, entitled “Haptic feedback for touchpads and other touch controls” and assigned to Immersion Corp. 
         [0011]    A piezoelectric crystal transducer (“PZT”)  24  is coupled to touch panel surface  20  through impedance matching interface  26 . PZT  24  generates high frequency vibrations. In one embodiment, the frequency of the vibrations are in the range of approximately 20-100 KHz. Any other device capable of generating vibrations in this range can be substituted for PZT  24  in other embodiments of the present invention. 
         [0012]    Impedance matching interface  26  is placed between PZT  24  and touch panel surface  20  to enable high efficiency ultrasonic energy transduction. In one embodiment, impedance matching interface  26  is formed of multiple layers of polyurethane material and transfers the high frequency waves generated by PZT  24  to touch panel surface  20 . 
         [0013]    A non-visible substrate  22  is placed on touch panel surface  20 . Substrate  22  enables the creation of high pressure regions on touch panel surface  20 . In one embodiment, substrate  22  is a coating that may be applied through chemical deposition. In another embodiment, substrate  22  is a transparency that is applied to surface  20 . Substrate  22  should be durable so that frequent touches on surface  20  does not wear it out, should include edges perpendicular to the X axis to generate pressure waves  28  on surface  20  when vibrated by PZT  24 , and should not significantly interfere with the transmission of light. In another embodiment, substrate  22  can be a liquid that is frequently reapplied to surface  20  when needed to facilitate cleaning. 
         [0014]    In operation, PZT  24  through interface  26  causes surface  20  to vibrated in generally the X direction at approximately 20-100 KHz. At this frequency, the air surrounding substrate  22  is compressed to create pressure waves  28 . Pressure waves  28  will destroy substantially all of the bacteria and other microorganisms and contaminants that have formed or have been applied to surface  20  through non-contact ultrasound and/or cavitation. 
         [0015]    In one embodiment, PZT  24  is computer controlled so that it can be cycled through a large range of frequencies, thus creating pressure waves across the frequency range. It is known that some bacteria, microorganisms, and other contaminants have a naturally occurring frequency, and the generation of a frequency at this natural frequency will destroy the material by breaking down the chemical bonds in the material. Generated frequencies may also weaken or destroy the adhesive bonds that join contaminants with the touch panel surface. Thus, PZT  24  can be activated to generate frequencies that are at the natural frequencies of all known materials that are desired to be destroyed. 
         [0016]    In another embodiment, the pressure waves may destroy some or all of the contaminants present on surface  20 , leaving non-toxic compounds on surface  20 . However, other contaminants, rather than being destroyed, will have their bonds to surface  20  merely weakened. Therefore, an air mechanism  25  can be used to induce an airflow across surface  20  to blow the non-toxic compounds and compounds having weakened bonds into the air, thus leaving surface  20  contaminant free. 
         [0017]      FIG. 2  is a flow diagram of the functionality of one embodiment of the present invention to sanitize a touch panel surface. PZT  24  generates vibrations in the range of 20-100 Khz ( 110 ). The vibrations are coupled to the touch panel surface having a substrate through the impedance matching layer ( 120 ). The vibrations induce pressure waves through the substrate ( 130 ). The pressure waves destroy or weaken the bonds of contaminants. 
         [0018]    As disclosed, embodiments of the present invention use vibrations to generate pressure waves that destroy contaminants on a touch panel surface without the need of human intervention or cleaning chemicals. Therefore, users will have less health concerns when using publicly available touch panels. 
         [0019]    Several embodiments of the present invention are specifically illustrated and/or described herein. However, it will be appreciated that modifications and variations of the present invention are covered by the above teachings and within the purview of the appended claims without departing from the spirit and intended scope of the invention.