Planar waveguide lens design

• US 8,064,744 B2
• Filed: 11/10/2006
• Issued: 11/22/2011
• Est. Priority Date: 11/10/2006
• Status: Expired due to Fees

• Current Assignee: Zetta Research and Development LLC - RPO Series (Zetta Research, LLC)
• Original Assignee: RPO Pty Limited (RPO, Inc.)
• Inventors: Atkins, Graham Roy, Kukulj, Dax, Charters, Robert Bruce
• Primary Examiner(s): Lepisto, Ryan
• Assistant Examiner(s): BLEVINS, JERRY M
• Application Number:
  US11/558,587
• Publication Number:
  US 20080111796A1
• Time in Patent Office: 1,838 Days
• Field of Search: 385/33, 385/31, 385/37, 385/132, 345/175, 345/179, 359/625, 359/626
• US Class Current: 385/33
• CPC Class Codes: G02B 2006/12102 Lens
• CPC Class Codes: G02B 2006/1219 Polymerisation
• CPC Class Codes: G02B 27/30 Collimators
• CPC Class Codes: G02B 6/12004 Combinations of two or more optical elements
• CPC Class Codes: G02B 6/1221 made from organic materials
• 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: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

This invention relates to an improved design for the transmit and receive optical elements of a waveguide-based optical touch screen sensor, where at least one converging lens is incorporated within the body of each transmit and receive element. The optical elements of the improved design are more mechanically robust, easier to incorporate into the touch screen assembly, and are less susceptible to stray light and the ingress of foreign matter. In one embodiment the converging lens collimates the light into a plane wave. In another embodiment the converging lens focuses the light to an external point. In yet another embodiment, each transmit and receive element also includes at least one diverging lens. The transmit and receive elements and associated waveguides preferably comprise photo-patternable polymers.

Claims

1. An input device for an electronic device comprising:

at least one light source;

at least one light detector to detect light intensity at a plurality of light detecting elements;

an input area defining a plane; and

a waveguide structure including a plurality of waveguides with associated slab regions composed of a first material with first refractive index, each slab region providing a planar extension of its associated waveguide, wherein;

each of said associated slab regions has a substantially straight end face, and at least one converging lens located within;

said light source couples light into a first set of waveguides with associated first set of slab regions of said waveguide structure;

said first set of waveguides directs the light into said associated first set of slab regions;

said converging lenses focus the light in the plane of the input area to produce a first grid of light beams;

said first grid of light beams traverses the input area in a first direction and is directed to the light detecting elements of said light detector by a second set of waveguides with associated second set of slab regions of said waveguide structure; and

each light beam is focused to a point located within said input area.

2. An input device according to claim 1, wherein said converging lens is composed of a second material with refractive index different to that of said first material, and is selected from a group consisting of:

a Luneburg lens, a Fresnel lens, a chirped grating, an in-plane lens or a combination thereof.

3. An input device according to claim 2, wherein said converging lens is an in-plane lens, and wherein said converging lens is composed of a second material with refractive index less than the refractive index of said first material, and is bi-concave, plano-concave or meniscus concave in shape.

4. An input device according to claim 3, wherein said second material is air.

5. An input device according to claim 1, wherein each associated slab region additionally contains at least one diverging lens.

6. An input device according to claim 5, wherein each associated slab region contains one diverging lens and one converging lens in a beam expander configuration.

7. An input device for an electronic device comprising:

at least one light source;

at least one light detector to detect light intensity at a plurality of light detecting elements;

an input area defining a plane; and

a waveguide structure including a plurality of waveguides with associated slab regions composed of a first material with first refractive index, each slab region providing a planar extension of its associated waveguide, wherein;

each of said associated slab regions has a substantially straight end face, and at least one converging lens located within;

said light source couples light into a first set of waveguides with associated first set of slab regions of said waveguide structure;

said first set of waveguides directs the light into said associated first set of slab regions;

said converging lenses focus the light in the plane of the input area to produce a first grid of light beams;

said first grid of light beams traverses the input area in a first direction and is directed to the light detecting elements of said light detector by a second set of waveguides with associated second set of slab regions of said waveguide structure;

said light source couples light into a third set of waveguides with associated third set of slab regions of said waveguide structure;

said third set of waveguides directs the light into said associated third set of slab regions;

said converging lenses focus the light in the plane of the input area to produce a second grid of light beams;

said second grid of light beams traverses the input area in a second direction, different to the first direction, and is directed to the light detecting elements of said light detector by a fourth set of waveguides with associated fourth set of slab regions of said waveguide structure; and

each light beam is focused to a point located within said input area.

8. An input device according to claim 7, wherein said input area is quadrilateral, said first and third sets of waveguides with associated first and third sets of slab regions are arranged along adjacent first and third edges of the input area, and said second and fourth sets of waveguides with associated second and fourth sets of slab regions are arranged along adjacent second and fourth edges of the input area, wherein the input area is rectangular, and the second direction is substantially perpendicular to the first direction, and wherein the end faces of the first, second, third and fourth sets of slab regions associated with the first, second, third and fourth sets of waveguides are substantially parallel to the corresponding edges of the input area.

9. An input device according to claim 8, additionally comprising:

first and second external lenses proximate to the ends of the first and second sets of slab regions associated with the first and second sets of waveguides, said first and second external lenses adapted to collimate the first grid of light beams in the direction perpendicular to the input area plane; and

third and fourth external lenses proximate to the ends of the third and fourth sets of slab regions associated with the third and fourth sets of waveguides, said third and fourth external lenses adapted to collimate the second grid of light beams in the direction perpendicular to the input area plane, wherein the end faces of the first, second, third and fourth sets of slab regions are located in the focal planes of the first, second, third and fourth external lenses.

10. An input device according to claim 9, additionally comprising a transparent material between the ends of the first, second, third and fourth sets of slab regions and the first, second, third and fourth external lenses, wherein said transparent material is an adhesive, for attaching each external lens to its respective set of waveguides and associated slab regions, wherein said transparent material has a refractive index substantially equal to the refractive index of said first material.

11. An input device for an electronic device, said input device comprising:

an input area;

a slab waveguide formed from a first material, said slab waveguide having a first end and a second end and having a converging lens located therein;

an optical waveguide having a distal end and a proximal end, said proximal end being in optical communication with said first end of said slab waveguide, wherein said second end of said slab waveguide is straight and substantially parallel to a side of said input area; and

an optical source in optical communication with said distal end of said optical waveguide, the arrangement being such that, in use, light from said optical source is guided in said optical waveguide to said slab waveguide, focused in the plane of said input area by said converging lens, and launched across said input area from said second end of said slab waveguide, wherein said converging lens is configured to focus said light to a point within said input area.

12. An input device according to claim 11, wherein said converging lens is formed from a second material with a refractive index different to the refractive index of said first material, and is selected from a group consisting of:

a Luneburg lens, a Fresnel lens, a chirped grating, an in-plane lens or a combination thereof.

13. An input device according to claim 12, wherein the second material has refractive index less than said first material.

14. An input device according to claim 13, wherein said second material is air.

15. An input device according to claim 11, wherein said slab waveguide additionally contains a diverging lens.

16. An input device according to claim 15, wherein said diverging lens and said converging lens are in a beam expander configuration.

17. An input device according to claim 11, wherein said optical waveguide is formed from said first material and is integrally formed with said first end of said slab waveguide.

18. An input device according to claim 11, further comprising an external lens for focusing said light in the direction substantially perpendicular to the plane of said input area, said external lens having a longitudinal axis, wherein said external lens is positioned with said longitudinal axis substantially parallel to said second end of said slab waveguide.

19. An input device for an electronic device, said input device comprising:

an input area;

a plurality of slab waveguides formed from a first material, each said slab waveguide having a first end and a second end and having a converging lens located therein;

a like plurality of optical waveguides each having a distal end and a proximal end, said proximal ends being in optical communication with said first ends of corresponding slab waveguides, wherein said second ends of said slab waveguides are straight and substantially parallel to a side of said input area; and

an optical source in optical communication with said distal ends of said optical waveguides, the arrangement being such that, in use, light from said optical source is guided in said optical waveguides to said slab waveguides, focused in the plane of said input area by said converging lenses, and launched across said input area from said second ends of said slab waveguides, wherein each said converging lens is configured to focus said light to a point within said input area.

20. An input device for an electronic device, said input device comprising:

an input area;

a slab waveguide formed from a first material, said slab waveguide having a first end and a second end and having a converging lens located therein;

an optical waveguide having a distal end and a proximal end, said proximal end being in optical communication with said first end of said slab waveguide, wherein said second end of said slab waveguide is straight and substantially parallel to a side of said input area;

an optical source adapted to launch light across said input area towards said second end of said slab waveguide; and

a detector in optical communication with said distal end of said optical waveguide, wherein said converging lens is configured to collect light emanating from a focal point within said input area and focus said light into said optical waveguide, and said optical waveguide guides said light to said detector.

21. An input device according to claim 20, wherein said converging lens is formed from a second material with a refractive index different to the refractive index of said first material, and is selected from a group consisting of:

a Luneburg lens, a Fresnel lens, a chirped grating, an in-plane lens or a combination thereof.

22. An input device according to claim 21, wherein the second material has refractive index less than said first material.

23. An input device according to claim 22, wherein said second material is air.

24. An input device according to claim 20, wherein said slab waveguide additionally contains a diverging lens.

25. An input device according to claim 24, wherein said diverging lens and said converging lens are in a beam expander configuration.

26. An input device according to claim 20, wherein said optical waveguide is formed from said first material and is integrally formed with said first end of said slab waveguide.

27. An input device according to claim 20, further comprising an external lens for focusing said light in the direction substantially perpendicular to the plane of said input area, said external lens having a longitudinal axis, wherein said external lens is positioned with said longitudinal axis substantially parallel to said second end of said slab waveguide.

28. An input device for an electronic device, said input device comprising:

an input area;

a plurality of slab waveguides formed from a first material, each said slab waveguide having a first end and a second end and having a converging lens located therein;

a like plurality of optical waveguides each having a distal end and a proximal end, said proximal ends being in optical communication with said first ends of corresponding slab waveguides, wherein said second ends of said slab waveguides are straight and substantially parallel to a side of said input area;

an optical source adapted to launch light across said input area towards said second ends of said slab waveguides; and

a multi-element detector in optical communication with said distal ends of said optical waveguides, wherein each said converging lens is configured to collect light emanating from a focal point within said input area and focus said light into a corresponding optical waveguide, and said optical waveguides guide said light to elements of said multi-element detector.