Position digitizer waveguide array with integrated collimating optics

• US 6,181,842 B1
• Filed: 01/10/2000
• Issued: 01/30/2001
• Est. Priority Date: 01/10/2000
• Status: Expired due to Fees

• Current Assignee: POA Sana Liquidating Trust
• Original Assignee: POA Sana, Inc. (Waveguide Technologies, Inc.)
• Inventors: Graham, David S., Francis, Daniel A.
• Primary Examiner(s): Ullah, Akm E.
• Application Number:
  US09/480,342
• Time in Patent Office: 386 Days
• Field of Search: 385/4, 359/276, 359/277, 359/289, 359/619, 359/621, 359/710, 372/101, 372/50, 372/107, 257/88, 257/98, 369/44.12, 369/44.23, 369/44.28, 369/44.29, 369/112
• US Class Current: 385/14
• CPC Class Codes: G02B 6/12004 Combinations of two or more optical elements
• 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: G02B 6/4202 for coupling an active element with fibres without intermediate optical elements, e.g. fibres with plane ends, fibres with shaped ends, bundles
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

XY position digitizer 10 has an X send substrate 11X with an associated X receive substrate 12X, and a Y send substrate 11Y with an associated Y receive substrate 12Y, defining free space region 10F therebetween. Send waveguides 13X are embedded in the X send substrate and send waveguides 13Y are embedded in the Y send substrate. The send waveguides sends an array of send light beams 15X across the free space region to the X receive substrate. The send waveguides likewise sends an array of send light beams 15Y across the free space region to the Y receive substrate. Receive waveguides 16X are embedded in the X receive substrate and receive waveguides 16Y are embedded in the Y receive substrate in correspondence with the X and Y send waveguides. Each receive waveguide receives at least a portion of the light beam from the corresponding send waveguide. An array of X send optical systems 18X are embedded in the X send substrate. One send optical system is in precise optical alignment with each send waveguide, for enhancing the collimation of the constrained send light from that aligned send waveguide.

Claims

1. A waveguide apparatus, comprising:

a send substrate and an opposed receive substrate spaced from the send substrate defining a free space region therebetween;

send waveguides embedded in the send substrate, each send waveguide having a free space end proximate the free space region and a light source end and guides constrained send light from the source end to the space end, the space ends of the send waveguides forming a parallel send array for sending a generally parallel array of unconstrained send light beams across the free space region to the receive substrate;

receive waveguides embedded in the receive substrate, each receive waveguide having a free space end proximate the free space region and a light detect end and guides constrained receive light from the space end to the detect end, the space ends of the receive waveguides forming a parallel receive array, each receive waveguide of the receive array in optical association with a corresponding send waveguide of the send array for receiving at least a portion of the light beam from the corresponding send waveguide which becomes constrained receive light in that receive waveguide; and

an array of send optical systems embedded in the send substrate between the send array and the free space region, one send optical system in an optically aligned fixed position relative to each send waveguide, which optical system enhances the collimation of the constrained send light from that aligned send waveguide, for enhancing the collimation of the light beams crossing the free space region causing a higher portion of the light beam to be received by the corresponding receive waveguide.

2. The waveguide apparatus of claim 1, wherein each send optical system comprises a series of spaced lenses embedded in the send substrate, each lens optically aligned with the other lenses along a common optical axis which is parallel with the space end of the aligned send waveguide, for progressively enhancing the collimation of the constrained send light with respect to the common center line.

3. The waveguide apparatus of claim 2, wherein the lenses of the send optical system are made of an optical material having an index of refraction N_L;

and the send substrate is made of an optical material having an index of refraction N_S which is less than N_L.

4. The waveguide apparatus of claim 3, wherein the send substrate material occupies the space between the lenses and is in optical contact with the surface of the lenses for providing a refractive interface.

5. The waveguide apparatus of claim 2, wherein the lenses of the send optical system are uniform in size.

6. The waveguide apparatus of claim 2, wherein the lenses in each series of lenses becomes progressively larger with distance from the aligned send waveguide.

7. The waveguide apparatus of claim 1, wherein each send optical system comprises:

a well indentation in the send substrate in a fixed position proximate a send waveguide; and

a lens mounted in the indentation and retained in the optically aligned position relative to that send waveguide.

8. The waveguide apparatus of claim 7, wherein the lenses mounted in the indentations are spherical to facilitate rolling into the indentations during completion of the waveguide apparatus.

9. The waveguide apparatus of claim 8, wherein the indentations are cylindrical and of like diameter as the spherical lenses to facilitate retaining the lenses in the optically aligned position after completion of the waveguide apparatus.

10. The waveguide apparatus of claim 7, further comprising a closure structure over the array of send optical systems for retaining the lenses in the indentations after completion of the waveguide apparatus.

11. The waveguide apparatus of claim 1, further comprising an array of light spread zones in the send substrate, one spread zone positioned between the space end of each send waveguide and the send optical system aligned therewith, each spread zone having a waveguide end proximate the send waveguide and an optical end proximate the send optical system, for permitting off-angle light within the constrained send light from that send waveguide to spread as the send light propagates through the spread zone toward the aligned send optical system.

12. The waveguide apparatus of claim 11, wherein both the zone array and the send waveguides are made of an optical material having an index of refraction N_G, and the send substrate is made of an optical material having an index of refraction N_S which is less than N_G.

13. The waveguide apparatus of claim 12, wherein the optical end of the spread zone has a convex contoured surface cooperating with the send optical system for enhancing the collimation of the light beam.

14. The waveguide apparatus of claim 12, wherein send substrate material occupies the space between optical end of each spread zone and the send optical system, and is in optical contact with the surface of optical end and the send optical system for providing a refractive interface therebetween.

15. The waveguide apparatus of claim 12, wherein the apparatus is oriented within an XYZ coordinate system in which:

the send waveguides extend generally in the X direction;

the light beams propagate generally in the X direction;

the S and R substrates extend generally in the Y direction;

the Z direction is perpendicular to both the X direction and the Y direction;

the space end of each send waveguide has

a Y dimension Ey and

a Z dimension Ez; and

each spread zone has

an X dimension Sx and

a Y dimension Sy and

a Z dimension Sz.

16. The waveguide apparatus of claim 15, wherein, the Sy dimension of each spread zone is sufficiently greater than the Ey dimension of each waveguide, to permit the spreading send light in the Y direction while propagating through the spread zone.

17. The waveguide apparatus of claim 16, wherein the Y direction spreading across the spread zone is unconstrained.

18. The waveguide apparatus of claim 16, wherein the spread zone array further comprises Y cladding of substrate material having a thickness in the Y direction and extending in the X and Z directions between adjacent spread zones, defining an X direction collimation taper for each spread zone, having a narrow end proximate the send waveguide and having a wide end proximate the send optical system, for constraining the Y direction spreading by redirecting Y direction off-angle send light towards the send optical system to further enhance the collimation of light beams crossing the free space region.

19. The waveguide apparatus of claim 16, further comprising Z cladding covers of substrate material having a thickness in the Z direction and extending in the X and Y directions along the Z sides of the spread zone array, for constraining the spreading send light against unconstrained Z spreading.

20. The waveguide apparatus of claim 19, wherein the Sz dimension of each spread zone is equal to the Ez dimension of each send waveguide, for constraining the spreading send light against any spreading in the Z direction.

21. The waveguide apparatus of claim 19, wherein the Sz dimension of each spread zone is greater than the Ez dimension of each send waveguide, for permitting limited spreading of the spreading send light in the Z direction.

22. The waveguide apparatus of claim 1, further comprising an array of adjacent receive optical systems embedded in the receive substrate between the free space region and the receive array, one receive optical system in optical alignment with each receive waveguide, for condensing at least a portion of the light beam crossing the free space region from the corresponding send waveguide which is in optical association with that receive waveguide.

23. The waveguide apparatus of claim 22, wherein each receive optical system comprises a series of spaced lenses embedded in the receive substrate, each lens optically aligned with the other lenses along a common optical axis which is parallel with the space end of the aligned receive waveguide, for progressively condensing the received portion of the light beam.

24. The waveguide apparatus of claim 22, wherein each receive optical system comprises a collection flare guide extending from the receive waveguide optically aligned therewith, having a wide end facing the free space region for collecting the received portion of the light beam, and having a narrow end facing the aligned receive waveguide for presenting the collected received light to the aligned receive waveguide.

25. The waveguide apparatus of claim 24, wherein each collection flare guide is spaced from the adjacent collection flare guides defining a dead sector between adjacent collection flare guides and defining a collection window at each collection flare guide, the dead sectors absorb marginally collimated light in the light beams, and the collection windows collect adequately collimated light in the light beams, to reduce cross-over interference of the light beams between adjacent collection flare guides.

26. The waveguide apparatus of claim 24, wherein each collection flare guide is flush with the adjacent collection flare guides defining continuous collection windows, which collect marginally collimated light and adequately collimated light in the light beam to conserve send light.

27. The waveguide apparatus of claim 1, further comprising a light source in light communication with the source end of the send waveguides for providing the send light which forms the light beams.

28. The waveguide apparatus of claim 1, further comprising an array of light detector cells in light communication with the detect end of the receive waveguides for individually detecting the constrained receive light guided by each receive waveguide.

29. The waveguide apparatus of claim 28, wherein:

the receive waveguides are made of an optical material having an index of refraction N_G; and

the receive substrate is made of an optical material having an index of refraction N_S which is less than N_G; and

the substrate optical material extends between adjacent waveguides forming an optical cladding, which spaces adjacent waveguides permitting limited misalignment of the detector cell array with respect to the detect ends of the receive waveguides.

30. The waveguide apparatus of claim 28, wherein the cell density in the light detector cell array is greater than the guide density of the detect ends of the receive waveguides, to provide at least two cells per guide.

31. The waveguide apparatus of claim 1, further comprising light filter in light communication with the receive waveguides for filtering the constrained receive light.

32. The waveguide apparatus of claim 31, wherein the light filter is mounted on the detect end of the receive waveguides.

33. The waveguide apparatus of claim 31, wherein the light filter is mounted on the space end of the receive waveguides.

34. The waveguide apparatus of claim 31, wherein the light filter is embedded in the receive waveguides.

35. The waveguide apparatus of claim 31, wherein the light filter is an interference filter.

36. The waveguide apparatus of claim 31, wherein the light filter is a diffraction grating.

37. The waveguide apparatus of claim 1, wherein the send waveguides are embedded in furrow indentations in the send substrate, and the send optical systems are embedded in well indentations in the send substrate, which indentations are formed by displacing substrate material with a stamping die, to precisely integrate the position of the send waveguides and the send optical systems relative to one another within the send substrate.

38. The waveguide apparatus of claim 1, wherein the send waveguides are embedded in furrow channels in the send substrate, and the send optical systems are embedded in well channels in the send substrate, which channels are formed by altering substrate material through lithography, to precisely integrate the position of the send waveguides and the send optical systems relative to one another within the send substrate.

39. An XY digitizer oriented within an XY coordinate system with respect to a free space region, comprising:

an X send substrate extending generally in the Y direction;

an X receive substrate extending generally in the Y direction and spaced from the X send substrate defining the X dimension of the free space region;

a Y send substrate extending generally in the X direction;

a Y receive substrate extending generally in the X direction and spaced from the Y send substrate defining the Y dimension of the free space region;

X send waveguides embedded in the X send substrate and extending generally in the Y direction;

Y send waveguides embedded in the Y send substrate and extending generally in the X direction;

each send waveguide having a free space end proximate the free space region and a light source end and guides constrained send light from the source end to the space end, the space ends of the send waveguides forming a parallel X send array and forming a parallel Y send array;

the X parallel send array sending a generally parallel array of unconstrained X send light beams generally in the X direction across the free space region to the X receive substrate;

the Y parallel send array sending a generally parallel array of unconstrained Y send light beams generally in the Y direction across the free space region to the Y receive substrate;

X receive waveguides embedded in the X receive substrate and extending generally in the Y direction;

Y receive waveguides embedded in the Y receive substrate and extending generally in the X direction;

each receive waveguide having a free space end proximate the free space region and a light detect end and guides constrained receive light from the space end to the detect end, the space ends of the receive waveguides forming a parallel X receive array and forming a parallel Y receive array;

each receive waveguide of the receive arrays in optical association with a corresponding send waveguide of the send arrays for receiving at least a portion of the light beam from the corresponding send waveguide to become constrained receive light in that receive waveguide;

an array of X send optical systems embedded in the X send substrate between the X send array and the free space region;

an array of Y send optical systems embedded in the Y send substrate between the Y send array and the free space region; and

one send optical system in optical alignment with each send waveguide which enhances the collimation of the constrained send light from that aligned send waveguide, for enhancing the collimation of the light beams crossing the free space region causing a higher portion of the light beam to be received by the corresponding receive waveguide.

40. The XY digitizer of claim 39, further comprising:

an array of X receive optical systems embedded in the X receive substrate and extending generally in the Y direction;

an array of Y receive optical systems embedded in the Y receive substrate and extending generally in the X direction;

the receive optical systems positioned between the free space region and receive arrays, one receive optical system in optical alignment with each receive waveguide,

for condensing at least a portion of the light beam crossing the free space region from the corresponding send waveguide which is in optical association with that receive waveguide.

41. The XY digitizer of claim 39, further comprising:

an X light source in light communication with the source end of the X send waveguides for providing the send light which forms the X light beams; and

a Y light source in light communication with the source end of the Y send waveguides for providing the send light which forms the Y light beams.

42. The XY digitizer of claim 39, further comprising:

X light detectors in light communication with the detect end of the X receive waveguides for detecting light in the X constrained receive light; and

Y light detectors in light communication with the detect end of the Y receive waveguide for detecting light in the Y constrained receive light.

43. The XY digitizer of claim 39, further comprising:

an X light filter in light communication with the detect end of the X receive waveguides for filtering light in the constrained receive light; and

a Y light filter in light communication with the detect end of the Y receive waveguide for filtering light in the Y constrained receive light.

44. The XY digitizer of claim 39, wherein the X send substrate and the X receive substrate and the Y send substrate and the Y receive substrate form a single piece substrate around the free space region.

45. The XY digitizer of claim 44, further comprising a display monitor supporting the single piece substrate with screen of the monitor coincident with to the free space region.