Apparatus and method for a folded optical element waveguide for use with light based touch screens

• US 20060001653A1
• Filed: 08/20/2004
• Published: 01/05/2006
• Est. Priority Date: 06/30/2004
• Status: Active Grant

• Current Assignee: POA Sana Liquidating Trust
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Smits, Gerard Dirk
• Granted Patent: US 8,184,108 B2
• Time in Patent Office: Days
• US Class Current: 345/176
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

A folded optical element waveguide that allows a minimum width bezel to be used around the perimeter of a light-based touch screen display. The apparatus and method includes a touch screen and a waveguide substrate provided adjacent the touch screen. The waveguide substrate includes a plurality of waveguides and a plurality of optical elements provided adjacent the touch screen. The waveguides include an internally reflective surface to reflect light perpendicular to the surface of the touch screen. The emitting and detecting waveguides are thus folded and provided around the side edges of the display. As a result, the width of the bezel around the display can be minimized.

Claims

1. An apparatus, comprising;

a touch screen; and

a waveguide substrate provided adjacent the touch screen, the waveguide substrate including a plurality of waveguides, the waveguides including an internally reflective surface to reflect light traveling in a first direction along a first axis to a second direction along a second axis.

2. The apparatus of claim 1, wherein the first axis is perpendicular to the second axis.

3. The apparatus of claim 1, wherein the waveguide substrate further comprises a plurality of optical elements optically coupled to the plurality of waveguides respectively.

4. The apparatus of claim 1, wherein the internally reflective surface is a transparent surface formed at a substantially forty-five degree angle with respect to the first axis and the second axis.

5. The apparatus of claim 3, wherein the plurality of optical elements are provided on a first surface of the waveguide substrate and the plurality of waveguides are provided on one or more second surfaces of the waveguide substrate, the first surface and the one or more second surfaces perpendicular to one another respectively.

6. The apparatus of claim 5, wherein a first subset of the plurality of optical elements provided on the first surface of the waveguide substrate are configured to provide light adjacent the touch screen.

7. The apparatus of claim 6, wherein a first subset of the plurality of waveguides are provided to provide light from a light source to the first subset of optical elements respectively.

8. The apparatus of claim 5, wherein a second subset of the plurality of optical elements provided on the first surface of the waveguide substrate are configured to receive light adjacent the touch screen.

9. The apparatus of claim 8, wherein a second subset of the plurality of waveguides are provided to convey light received by the second subset of optical elements to a light imaging device.

10. The apparatus of claim 1 wherein the waveguide substrate further comprises a bezel surrounding the perimeter of the touch screen.

11. The apparatus of claim 10, further comprises a plurality of optical elements cladded by the bezel of the waveguide substrate.

12. The apparatus of claim 3, wherein the optical elements comprise collimated lenses.

13. The apparatus of claim 3, wherein a first subset of the optical elements are configured to generate a lamina of light adjacent the touch screen and a second subset of the optical elements are configured to detect interrupts in the lamina of light.

14. The apparatus of claim 3, wherein a first subset of the optical elements are configured to generate a grid of light adjacent the touch screen and a second subset of the optical elements are configured to detect interrupts in the grid of light.

15. An method, comprising;

providing a touch screen; and

providing a waveguide substrate adjacent the touch screen, the waveguide substrate including a plurality of waveguides, the waveguides including an internally reflective surface to reflect light traveling in a first direction along a first axis to a second direction along a second axis.

16. The method of claim 15, wherein the first axis is perpendicular to the second axis.

17. The method of claim 15, further comprising providing, on the waveguide substrate, a plurality of optical elements optically coupled to the plurality of waveguides respectively.

18. The method of claim 15, further comprising forming the internally reflective surface with a transparent surface at a substantially forty-five degree angle with respect to the first axis and the second axis.

19. The method of claim 17, further comprising providing the plurality of optical elements on a first surface of the waveguide substrate and providing the plurality of waveguides on one or more second surfaces of the waveguide substrate, the first surface and the one or more second surfaces perpendicular to one another respectively.

20. The method of claim 19, further comprising providing a first subset of the plurality of optical elements on the first surface of the waveguide substrate to provide light adjacent the touch screen.

21. The method of claim 20, further providing a light source to provide light from to the first subset of optical elements respectively.

22. The method of claim 19, further comprising providing a second subset of the plurality of optical elements on the first surface of the waveguide substrate to receive light adjacent the touch screen.

23. The apparatus of claim 22, further providing the second subset of the plurality of optical elements to convey light received by the second subset of optical elements to a light imaging device.

24. The method of claim 15, further comprising providing a bezel on the waveguide substrate surrounding the perimeter of the touch screen.

25. The method of claim 24, further comprises cladding a plurality of optical elements within the bezel of the waveguide substrate.

26. The method of claim 15, further providing a first set of optical elements to generate a lamina of light adjacent the touch screen and a second subset of the optical elements to detect interrupts in the lamina of light.

27. The method of claim 15, further providing a first set of optical elements to generate a grid of light adjacent the touch screen and a second subset of the optical elements to detect interrupts in the grid of light.