Apparatus and method for a molded waveguide for use with touch screen displays

• US 20050271319A1
• Filed: 06/04/2004
• Published: 12/08/2005
• Est. Priority Date: 06/04/2004
• Status: Active Grant

• Current Assignee: POA Sana Liquidating Trust
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Graham, David S.
• Granted Patent: US 7,471,865 B2
• Time in Patent Office: Days
• US Class Current: 385/14
• CPC Class Codes: G02B 6/124 Geodesic lenses or integrated gratings
• CPC Class Codes: G02B 6/138 by using polymerisation
• CPC Class Codes: G02B 6/32 having lens focusing means positioned between opposed fibre ends with lens being an integral part of the single fibre end G02B6/262
• CPC Class Codes: G02B 6/43 Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing

Abstract

An apparatus and method for an inexpensive, simple to make, self-aligning molded waveguide made of an optically transparent material and that can be used to generate a grid or lamina of light for use with touch screen displays. The molded waveguide substrate includes a plurality of lenses and a plurality of waveguide grooves corresponding to the plurality of integral lenses respectively. After the substrate is molded, the grooves are filled with an optically transparent material to optically couple and align the plurality of lenses and the plurality of grooves respectively. In one application, the molded waveguide substrate is positioned adjacent a touch screen device. A light transmitter and an imaging device are optically coupled to the molded waveguide substrate, and a processing device is coupled to the imaging device. The processing device is configured to determine a data entry to the touch screen by deciphering the coordinates of an interrupt in the light created in the free space adjacent the touch screen device when a data entry is being made to the touch screen device.

Claims

1. A method, comprising;

molding a waveguide substrate having

a plurality of optical elements; and

a plurality of waveguide grooves corresponding to the plurality of integral optical elements respectively;

filling the grooves with an optically transparent material; and

optically coupling the plurality of optical elements and the plurality of grooves filled with the optically transparent material respectively.

2. The method of claim 1, wherein the molding the plurality of optical elements further comprises molding a plurality of three-dimensional lenses.

3. The method of claim 1, wherein the molding of the plurality of optical elements further comprises molding the optical elements to have a dimension ranging from 50 to 2000 microns in diameter.

4. The method of claim 1, wherein the molding the plurality of waveguide grooves further comprises forming the grooves approximately 5 to 50 microns deep.

5. The method of claim 1, wherein the molding the plurality of waveguide grooves further comprises forming the grooves approximately 5 to 50 microns wide.

6. The method of claim 1, wherein the molding the waveguide substrate further comprises the molding of the substrate with a material having an index of refraction ranging from n=1.0 to 2.0.

7. The method of claim 1, further comprising molding the waveguide substrate from a material having a first index of refraction and filling the grooves with the optically transparent material having a second index of refraction, wherein the second index of refraction is greater than the first index of refraction.

8. The method of claim 1, further comprising molding the plurality of optical elements to create a lamina of light when light is provided to inputs of the waveguides grooves.

9. The method of claim 1, further comprising molding the plurality of optical elements to create a grid of light when light is provided to inputs of the waveguides grooves.

10. The method of claim 1, further comprising molding the waveguide substrate having a first sub-set of the plurality of waveguide grooves extending in a first direction along a first axis.

11. The method of claim 10, further comprising molding the waveguide substrate having a second sub-set of the plurality of waveguide grooves extending in a second direction along a second axis.

12. The method of claim 11, wherein the first axis and the second axis are perpendicular to each other.

13. The method of claim 1, further comprising molding the waveguide substrate such that the plurality of waveguide grooves extend on a first surface of the substrate and a second surface of the substrate, wherein the first surface and the second surface are either perpendicular or parallel to one another.

14. The method of claim 1, wherein a first sub-set of the plurality of waveguide grooves are configured to be optically coupled to a light emitter.

15. The method of claim 1, wherein a second sub-set of the plurality of grooves are configured to be optically coupled to an imaging device.

16. The method of claim 1, wherein the filling of the grooves further comprises using capillary action to fill the grooves with the optically transparent material.

17. The method of claim 1, wherein the filling of the grooves further comprises over-filling the grooves with the optically transparent material and then removing any excess of the optically transparent material.

18. The method of claim 1, further comprising curing the waveguide substrate after the grooves are filled with the optically transparent material.

19. The method of claim 1, further comprising optically aligning during the molding process the plurality of optical elements and the plurality of waveguide grooves respectively.

20. The method of claim 1, wherein molding the waveguide substrate further comprises molding the waveguide substrate into one of the following shapes:

a one a straight substrate;

square;

L-shaped, rectangle, triangle, round, or an oval shape.

21. The method of claim 1, further comprising:

positioning the molded waveguide substrate adjacent a touch screen device, the molded waveguide being configured to create light in the free space adjacent the touch screen device;

optically coupling a light transmitter to the molded waveguide substrate; and

optically coupling an imaging device to the molded waveguide substrate.

22. The method of claim 21, further comprising connecting a processing device to the imaging device, the processing device configured to determine a data entry to the touch screen by deciphering the coordinates of an interrupt in the light created in the free space adjacent the touch screen device when a data entry is being made to the touch screen device.

23. The method of claim 1, wherein the molding of the waveguide substrate further comprises molding the waveguide substrate using one of the following molding techniques:

injection molding;

compression molding;

embossing;

optical micro-molding.

24. The method of claim 1, wherein the optical elements comprise at least one of, but not limited to the following optical elements:

lenses, gratings, bragg gratings, coupling horns, etc.

46. The method of claim 1, wherein the filling the grooves with an optically transparent material further comprises one of the following:

using capillary action to fill the grooves with the optically transparent material;

coating the waveguide substrate with the optically transparent material and then etching the waveguide substrate to remove the optically transparent material from the substrate except in the areas of the grooves;

or

coating the waveguide substrate with a non-stick material except in the grooves and then dipping the waveguide substrate into the optically transparent material.

47. The method of claim 1, wherein the plurality of optical elements are half-circular in shape.

48. The apparatus of claim 24, wherein the plurality of optical elements are half-circular in shape.

25. An apparatus, comprising:

a molded waveguide substrate, the molded waveguide substrate including;

a plurality of optical elements; and

a plurality of waveguide grooves filled with an optically transparent material.

26. The apparatus of claim 25, wherein the plurality of optical elements are three-dimensional lenses.

27. The apparatus of claim 25, wherein the plurality of optical elements have a dimension ranging from 50 to 2000 microns in diameter.

28. The apparatus of claim 25, wherein the waveguide grooves are approximately 5 to 50 microns deep.

29. The apparatus of claim 25, wherein the waveguide grooves are approximately 5 to 50 microns wide.

30. The apparatus of claim 25, wherein the waveguide substrate has an index of refraction ranging from n=1.0 to 2.0.

31. The apparatus of claim 25, wherein the waveguide substrate is made from a material having a first index of refraction and the grooves are filled with the optically transparent material having a second index of refraction, wherein the second index of refraction is greater than the first index of refraction.

32. The apparatus of claim 25, wherein the plurality of optical elements are configured with optical properties to create a lamina of light when light is provided to inputs of the waveguides grooves.

33. The apparatus of claim 25, wherein the plurality of optical elements are configured with optical properties to create a grid of light when light is provided to inputs of the waveguides grooves.

34. The apparatus of claim 25, wherein the waveguide substrate is further configured with a first sub-set of the plurality of waveguide grooves extending in a first direction along a first axis.

35. The apparatus of claim 34, wherein the waveguide substrate is further configured with a second sub-set of the plurality of waveguide grooves extending in a second direction along a second axis.

36. The apparatus of claim 35, wherein the first axis and the second axis are either perpendicular or parallel to each other.

37. The apparatus of claim 25, wherein the waveguide substrate is further configured such that the plurality of waveguide grooves extend on a first surface of the substrate and a second surface of the substrate, wherein the first surface and the second surface are perpendicular to one another.

38. The apparatus of claim 25, wherein a first sub-set of the plurality of waveguide grooves are configured to be optically coupled to a light emitter.

39. The apparatus of claim 25, wherein a first sub-set of the plurality of grooves are configured to be optically coupled to an imaging device.

40. The apparatus of claim 25, wherein the plurality of lenses and the plurality of waveguide grooves are optically aligned respectively.

41. The apparatus of claim 25, wherein the waveguide substrate is molded into one the following shapes:

a straight substrate;

a square;

an L-shaped member, a rectangle, triangle, round, or oval.

42. The apparatus of claim 25, further comprising:

a touch screen device, the molded waveguide being configured to create light in the free space adjacent the touch screen device;

a light transmitter optically coupled to a first set of the waveguide grooves on the molded waveguide substrate; and

an imaging device optically coupled to a second set of the molded waveguide substrate.

43. The apparatus of claim 42, further comprising a processing device coupled to the imaging device, the processing device configured to determine a data entry to the touch screen by deciphering the coordinates of an interrupt in the light created in the free space adjacent the touch screen device when a data entry is being made to the touch screen device.

44. The apparatus of claim 25, wherein waveguide substrate is molded by one of the following:

injection molding;

compression molding;

embossing;

or optical micro-molding.

45. The apparatus of claim 25, wherein the optical elements comprise at least one of, but not limited to the following optical elements:

lenses, gratings, bragg gratings, coupling horns, etc.