Stress seal for acoustic wave touchscreens

• US 6,411,287 B1
• Filed: 09/08/1999
• Issued: 06/25/2002
• Est. Priority Date: 09/08/1999
• Status: Expired due to Fees

• Current Assignee: Tyco Electronics Corporation (TE Connectivity Limited)
• Original Assignee: Elo Touchsystems Incorporated (Elo Touch Solutions, Inc.)
• Inventors: Scharff, Daniel H., Armstrong, Don
• Primary Examiner(s): CHOW, DOON Y
• Application Number:
  US09/392,577
• Time in Patent Office: 1,021 Days
• Field of Search: 345/173, 345/174, 345/175, 345/176, 345/177, 345/178, 345/179, 345/180, 277/630, 277/654, 277/637, 277/628, 277/639, 341/22
• US Class Current: 345/177
• CPC Class Codes: G06F 3/043 using propagating acoustic waves

Abstract

A sealing system for use with acoustic touchscreens is provided. The system includes a seal coupled to a frame, the frame being positioned directly over the acoustic touchscreen components, e.g., acoustic transducers, reflective arrays, etc. such that the seal prevents contamination of the underlying components. The system uses a plurality of tensioning elements that are either integral to, or separate from, the frame. The tensioning elements are preferably coupled at the four corners of the CRT, and more preferably coupled to the CRT mounting tabs. Assuming an approximately spherically curved touchscreen surface, the tensioning elements provide a uniform compressive force per unit length along the entire perimeter of the seal. As a consequence of the tensioning elements, the frame can be extremely thin, lightweight, and flexible, thus allowing it to substantially conform to the shape of the touch surface. Additionally, a very small and uniform gap can be maintained between the frame and the touch surface, e.g. less than 1 millimeter, thus allowing the designer to select from a wider range of sealing materials that meet the acoustic signal absorption requirements of the system while providing a robust contamination seal.

Claims

1. An acoustic touchscreen system, comprising:

an acoustic touchscreen coupled to a display device, said acoustic touchscreen defining a touch-sensitive area on a corresponding touchscreen surface;

a frame mounted to said acoustic touchscreen, said frame located above said acoustic touchscreen, wherein a central opening in said frame substantially borders said touch-sensitive area;

a plurality of coupling means, each of said coupling means coupling a corner portion of said frame to said display device; and

a seal interposed between a lower surface of said frame and said acoustic touchscreen surface, wherein said frame imposes a substantially uniform compressive force on a portion of said seal contacting an approximately spherically curved portion of said acoustic touchscreen surface.

2. The acoustic touchscreen system of claim 1, wherein said acoustic touchscreen is a direct-on-tube acoustic touchscreen.

3. The acoustic touchscreen system of claim 1, wherein said acoustic touchscreen is an overlay acoustic touchscreen.

4. The acoustic touchscreen system of claim 1, said plurality of coupling means comprising a plurality of retaining straps.

5. The acoustic touchscreen system of claim 4, further comprising a plurality of mounting tabs rigidly coupled to said display device, wherein said plurality of retaining straps couple said plurality of mounting tabs to said frame corner portions.

6. The acoustic touchscreen system of claim 5, wherein each of said plurality of mounting tabs is rigidly coupled to each of a plurality of display device corners.

7. The acoustic touchscreen system of claim 5, wherein each of said plurality of mounting tabs is rigidly coupled to an implosion band encircling said display device, and wherein each of said plurality of mounting tabs is proximate each of a plurality of display device corners.

8. The acoustic touchscreen system of claim 4, said frame further comprising a grooved portion near each of said frame corner portions, wherein each of said plurality of retaining straps is held within each of said grooved portions.

9. The acoustic touchscreen system of claim 4, further comprising a retaining ring fixably coupled to said display device, wherein said plurality of retaining straps couple said retaining ring to said frame corner portions.

10. The acoustic touchscreen system of claim 1, said plurality of coupling means comprising a plurality of tensioning straps, wherein a portion of each of said plurality of tensioning straps is proximate an upper surface of said frame.

11. The acoustic touchscreen system of claim 10, further comprising a plurality of mounting tabs rigidly coupled to said display device, wherein said plurality of tensioning straps are coupled to said plurality of mounting tabs.

12. The acoustic touchscreen system of claim 11, wherein each of said plurality of mounting tabs is rigidly coupled to each of a plurality of display device corners.

13. The acoustic touchscreen system of claim 11, wherein each of said plurality of mounting tabs is rigidly coupled to an implosion band encircling said display device, and wherein each of said plurality of mounting tabs is proximate each of a plurality of display device corners.

14. The acoustic touchscreen system of claim 10, further comprising a retaining ring fixably coupled to said display device, wherein said plurality of tensioning straps are coupled to said retaining ring.

15. The acoustic touchscreen system of claim 1, wherein said seal is selected from the group of seals consisting of open cell foams, closed cell foams, expanded polymers, or gels.

16. The acoustic touchscreen system of claim 1, said frame further comprising a channel located on said lower surface and proximate to said central opening, wherein a portion of said seal is within said channel.

17. The acoustic touchscreen system of claim 1, said frame further comprising at least one wiring channel.

18. The acoustic touchscreen system of claim 1, further comprising a bezel assembly and a second seal, said second seal interposed between a portion of said bezel assembly and an upper surface of said frame.

19. The touchscreen system of claim 1, wherein two portions of said acoustic touchscreen surface are approximately spherically curved.

20. The touchscreen system of claim 1, wherein four portions of said acoustic touchscreen surface are approximately spherically curved.

21. The touchscreen system of claim 1, wherein said frame is plastic.

22. An acoustic touchscreen system, comprising:

an overlay acoustic touchscreen coupled to a display device, said overlay acoustic touchscreen defining a touch-sensitive area on a corresponding touchscreen surface;

a frame mounted to said overlay acoustic touchscreen, said frame located above said overlay acoustic touchscreen, wherein a central opening in said frame substantially borders said touch-sensitive area;

a plurality of coupling means, each of said coupling means coupling a corner portion of said frame to said overlay acoustic touchscreen; and

a seal interposed between a lower surface of said frame and said acoustic touchscreen surface, wherein said frame imposes a substantially uniform compressive force on a portion of said seal contacting an approximately spherically curved portion of said acoustic touchscreen surface.

23. The acoustic touchscreen system of claim 22, said plurality of coupling means comprising a plurality of clips.