Apparatus and method for making flexible waveguide substrates for use with light based touch screens

• US 20060002655A1
• 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 7,412,119 B2
• Time in Patent Office: Days
• US Class Current: 385/31
• CPC Class Codes: G02B 6/12004 Combinations of two or more optical elements
• CPC Class Codes: G02B 6/124 Geodesic lenses or integrated gratings
• CPC Class Codes: G02B 6/136 by etching
• 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 6/4206 Optical features G02B6/4207, G02B6/421 take precedence
• 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

Abstract

Flexible optical waveguide substrates that can be used with touch screen displays. The waveguide substrates include a flexible base material. A first optical layer having a first index of refraction value is formed on the flexible base material. A second optical layer is then formed on the first optical layer, the second optical layer being patterned to form a plurality of optical elements and waveguides respectively. The second optical layer also has a second index of refraction value higher than the first index of refraction value. Lastly, a third optical layer is formed on the second optical layer. The third optical layer has a third index of refraction value lower than the second index of refraction value. The high N second layer is therefore sandwiched between the lower N first and third layers, creating an internally reflective surface wherever the high N and low N materials are in contact. The base material and first, second and third optical layers thus form a flexible waveguide substrate.

Claims

1. An apparatus, comprising;

a flexible base material;

a first optical layer formed on the flexible base material, the first optically transparent layer having a first index of refraction value;

a second optical layer formed on the first optical layer, the second optical layer being patterned to form a plurality of optical elements and waveguides respectively, the second optical layer having a second index of refraction value higher than the first index of refraction value; and

a third optical layer formed on the second optical layer, the third optical layer having a third index of refraction value lower than the second index of refraction value,

the base material and first, second and third optical layers forming a flexible waveguide substrate.

2. The apparatus of claim 1, wherein the first index or refraction value and the third index of refraction value are substantially the same.

3. The apparatus of claim 1, wherein the flexible base material comprises one of the following materials:

plastic or polycarbonate.

4. The apparatus of claim 1, wherein the second optical layer is further patterned to form a plurality of internally reflective surfaces between the plurality of optical elements and waveguides respectively.

5. The apparatus of claim 4, wherein the plurality of optical elements are formed on a first surface of the waveguide substrate and the plurality of waveguides are formed on second surface of the waveguide substrate, wherein the first surface and the second surface are substantially at right angles with respect to one another.

6. The apparatus of claim 1, wherein the optical elements comprise one of the following types of optical elements:

lenses, diffraction gratings, filters, bragg gratings, or coupling horns.

7. The apparatus of claim 1, wherein the plurality of optical elements patterned in the second optical layer are arranged in multiples layers.

8. The apparatus of claim 7, wherein the plurality of optical elements in the multiples layers are interleaved.

9. The apparatus of claim 1, further comprising a light based touch screen having the flexible waveguide substrate formed substantially around the perimeter of the touch screen, a first sub-set of the plurality of optical elements of the flexible waveguide substrate being configured to provide light adjacent to the light based touch screen and a second sub-set of optical elements of the flexible waveguide substrate configured to detect data inputs made to the light based touch screen.

10. The apparatus of claim 9, further comprising a light source optically coupled to the waveguides associated with the first sub-set of optical elements respectively.

11. The apparatus of claim 10, further comprising a imaging device optically coupled to the waveguides associated with the second sub-set of optical elements respectively.

12. An apparatus, comprising

a flexible base material, the flexible base material having a plurality of flexible waveguide substrates formed thereon, each of the flexible waveguide substrates comprising:

a first optical layer formed on the flexible base material, the first optically transparent layer having a first index of refraction value;

a second optical layer formed on the first optical layer, the second optical layer being patterned to form a plurality of optical elements and waveguides respectively, the second optical layer having a second index of refraction value higher than the first index of refraction value; and

a third optical layer formed on the second optical layer, the third optical layer having a third index of refraction value lower than the second index of refraction value.

13. The apparatus of claim 12, wherein the plurality of substrates are arranged in parallel strips on the flexible base material.

14. The apparatus of claim 12, wherein the flexible base material is a continuous strip and the flexible waveguides substrates are serially formed on the flexible base material.

15. The apparatus of claim 12, wherein the waveguide substrates comprise a plurality optical elements and waveguides.

16. The apparatus of claim 15, wherein the optical elements are arranged in multiple layers and the optical elements are interleaved.

17. The apparatus of claim 15, wherein the optical elements comprise one of the following types of optical elements:

lenses, diffraction gratings, filters, bragg gratings, or coupling horns.

18. The apparatus of claim 12, wherein the flexible waveguide substrates are further patterned to form a plurality of internally reflective surfaces between the plurality of optical elements and waveguides respectively.

19. The apparatus of claim 18, wherein the plurality of optical elements are formed on a first surface of the flexible waveguide substrate and the plurality of waveguides are formed on second surface of the flexible waveguide substrate, wherein the first surface and the second surface are substantially at right angles with respect to one another.

20. A method comprising:

providing a first optical material over a flexible base material, the first optical material having a first index of refraction value;

providing a second optical layer on the first optical layer, the second optical layer having a second index of refraction value higher than the first index of refraction value;

patterning the second optical layer to form a plurality of optical elements and waveguides respectively; and

providing a third optical layer formed on the second optical layer, the third optical layer having a third index of refraction value lower than the second index of refraction value,

the base material and first, second and third optical layers forming a flexible waveguide substrate.

21. The method of claim 20, further comprising forming a plurality of the flexible waveguide substrates on the base material.

22. The method of claim 21, wherein the forming the plurality of flexible waveguide substrates further comprises:

providing the first, the second and the third optical layers in side-by-side strips on the base material; and

cutting the base material to singulate the individual flexible waveguide substrates.

23. The method of claim 22, wherein forming the plurality of flexible waveguide substrates further comprises:

providing the first, second and third optical layers serially at spaced intervals on a continuous strip of the flexible base material; and

cutting the continuous flexible base material at the spaced intervals to singulate the individual waveguide substrates.