Apparatus and method for an improved lens structure for polymer wave guides which maximizes free space light coupling

• US 7,369,724 B2
• Filed: 10/03/2006
• Issued: 05/06/2008
• Est. Priority Date: 10/03/2006
• Status: Expired due to Fees

• Current Assignee: POA Sana Liquidating Trust
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Deane, Peter
• Primary Examiner(s): Font; Frank G.
• Assistant Examiner(s): LEPISTO, RYAN A
• Application Number:
  US11/542,816
• Publication Number:
  US 20080080811A1
• Time in Patent Office: 581 Days
• Field of Search: 345/175, 345/176, 385/33
• US Class Current: 385/33
• 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 6/1228 Tapered waveguides, e.g. integrated spot-size transformers for coupling with fibres G02B6/305
• 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

A polymer waveguide assembly. The assembly includes a polymer waveguide have a plurality of waveguide cores and an associated plurality of lenses respectively. The assembly also includes a molded lens structure having a support region, a primary refractive surface and a secondary refractive lens. The polymer waveguide is positioned onto the support surface of the molded lens structure so that the waveguide lenses are in optical alignment with the primary refractive lens and the secondary refractive lens of the molded waveguide structure. The lenses of the polymer waveguide are capable of collimating in the X and Y directions respectively. The primary refractive lens and the secondary refractive lens are both capable of collimating light in the Z direction. With this arrangement, a substantial; portion of the light passing through the secondary lens toward the waveguide cores is within the acceptance angle of the plurality of waveguides lenses respectively. The secondary lens thus creates a shallow angle of convergence relative to the input of the plurality of lenses of the waveguide. As a result, issues caused by misalignment are minimized and optical coupling is improved.

Claims

1. A polymer waveguide assembly, comprising:

a polymer waveguide have a plurality of waveguide cores and an associated plurality of lenses respectively;

a molded lens structure having a support region to support the polymer waveguide, a primary refractive lens and a secondary refractive lens, the plurality of waveguide cores, the primary refractive lens and the secondary refractive lens of the molded lens structure integrated into a single structure,

wherein the plurality of waveguide lenses are in optical alignment with the primary refractive lens and the secondary refractive lens of the molded waveguide structure.

2. The assembly of claim 1, wherein the plurality of lenses of the polymer waveguide are capable of collimating in the X and Y plane.

3. The assembly of claim 1, wherein the primary refractive lens is capable of collimating light in the Z direction.

4. The assembly of claim 1, wherein the secondary refractive lens is capable of collimating light in the Z direction.

5. The assembly of claim 1, wherein the secondary refractive lens is positioned relative to the primary refractive lens and the plurality of waveguide lenses such that a substantial portion of the light passing through the secondary lens toward the waveguide cores is within the acceptance angle of the plurality of waveguides lenses respectively.

6. The assembly of claim 1, wherein the secondary refractive lens is positioned relative to the primary refractive lens and the plurality of waveguide lenses such that the secondary lens creates a shallow angle of convergence relative to the input of the plurality of lenses of the waveguide.

7. The assembly of claim 1, wherein the secondary refractive lens is positioned between the primary refractive lens and the plurality of lenses of the waveguide.

8. The assembly of claim 1, wherein the polymer waveguide comprises:

a first polymer layer; and

a second patterned polymer layer formed on the first polymer layer and patterned to form the plurality of waveguide cores optically aligned with the plurality of lenses.

9. The assembly of claim 8, wherein the first polymer layer is made of an optically transparent polymer having a index of refraction N1 and the second polymer layer has an index of refraction of N2, wherein N2 is greater than N1.

10. The assembly of claim 9, further comprising a third polymer layer formed over the second patterned polymer layer.

11. The assembly of claim 1, wherein the polymer waveguide comprises a first polymer layer, a second polymer layer and a third polymer layer, wherein the first polymer layer, the second patterned polymer layer, and the third polymer layer are made from an optically clear photopolymer consisting of:

Polysiloxanes, Polymethylmethacylates, epoxies, and other materials or a combination thereof.

12. An apparatus, further comprising:

a touch pad surface;

two of the assemblies of claim 1 positioned on opposing sides of the touch pad surface respectively, the first assembly being configured as a transmit waveguide and the second assembly being configured as a receive waveguide.

13. The apparatus of claim 12, further comprising a processor optically coupled to the receive waveguide and a light source optically coupled to the transmit waveguide.

14. A method, comprising:

providing a polymer waveguide have a plurality of waveguide cores and an associated plurality of lenses respectively;

providing a molded lens structure having a support region, a primary refractive lens and a secondary refractive lens, the provided plurality of waveguide cores provided on the support region so that the primary refractive lens and the secondary refractive lens of the molded lens structure and the waveguide cores are integrated into a single structure,

positioning the plurality of waveguide lenses on the support surface of the molded lens wherein the plurality of lenses of the polymer waveguide are in optical alignment with the primary refractive lens and the secondary refractive lens of the molded waveguide structure respectively.

15. The method of claim 14, wherein the plurality of lenses of the polymer waveguide are capable of collimating in the X and Y plane.

16. The method of claim 14, wherein the primary refractive lens is capable of collimating light in the Z direction.

17. The method of claim 14, wherein the secondary refractive lens is capable of collimating light in the Z direction.

18. The method of claim 14, wherein the secondary refractive lens is positioned relative to the primary refractive lens and the plurality of waveguide lenses such that a substantial;

portion of the light passing through the secondary lens toward the waveguide cores is within the acceptance angle of the plurality of waveguides lenses respectively.

19. The method of claim 14, wherein the secondary refractive lens is positioned relative to the primary refractive lens and the plurality of waveguide lenses such that the secondary lens creates a shallow angle of convergence relative to the input of the plurality of lenses of the waveguide.