Optical microstructures for light extraction and control

• US 8,380,026 B2
• Filed: 01/13/2009
• Issued: 02/19/2013
• Est. Priority Date: 01/24/2006
• Status: Expired due to Fees

• Current Assignee: Rambus Delaware
• Original Assignee: Rambus Inc.
• Inventors: Van Ostrand, Daniel K., King, Carey, Gobeli, Garth
• Primary Examiner(s): KIM, ELLEN E
• Application Number:
  US12/352,913
• Publication Number:
  US 20090122387A1
• Time in Patent Office: 1,498 Days
• Field of Search: 385/31, 385/39, 385/16, 359/291, 361/704, 361/707, 361/709, 361/710
• US Class Current: 385/31
• CPC Class Codes: G02B 6/00 Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
• CPC Class Codes: G02B 6/122 Basic optical elements, e.g. light-guiding paths
• CPC Class Codes: G02B 6/125 Bends, branchings or intersections
• CPC Class Codes: G02B 6/2852 using tapping light guides arranged sidewardly, e.g. in a non-parallel relationship with respect to the bus light guides (light extraction or launching through cladding, with or without surface discontinuities, bent structures)
• CPC Class Codes: G02B 6/351 involving stationary waveguides with moving interposed optical elements G02B6/3538 takes precedence; interposed waveguides G02B6/3502
• CPC Class Codes: G09G 3/3473 based on light coupled out of a light guide, e.g. due to scattering, by contracting the light guide with external means

Abstract

The application of optical microstructures improve the quality of light available to the viewer of an optical display system, or any display which works on the concept of moving one surface into direct contact or close proximity of a light guide to extract light through frustrated total internal reflection. Certain ones of the microstructures can act to assist in overcoming stiction between the surface and the light guide.

Claims

1. An optical shutter comprising:

a light guide through which light propagates via total internal reflection;

a positionable active layer configured to physically move between an on state position and an off state position, the positionable active layer located in proximity to the light guide, the positionable active layer having an internal surface that faces the light guide and an external surface that faces away from the light guide; and

a plurality of collimator features on the external surface of the positionable active layer that increase a probability of the light exiting the positionable active layer being emitted by the optical shutter.

2. The optical shutter as recited in claim 1, wherein optical properties of the plurality of collimator features are configured to direct the light that traverse the plurality of collimator features to exit external surfaces of the plurality of collimator features in a direction more nearly perpendicular to the external surface of the positionable active layer.

6. The optical shutter as recited in claim 1, wherein the plurality of collimator features change an angle of the light emitting from the optical shutter.

3. An optical shutter array system comprising:

a plurality of optical shutters on a display, wherein at least one of the plurality of optical shutters comprises;

a light guide through which light propagates via total internal reflection;

a positionable active layer configured to physically move between an on state position and an off state position, the positionable active layer located in proximity to the light guide, the positionable active layer having an internal surface that faces the light guide and an external surface that faces away from the light guide; and

a plurality of collimator features on the external surface of the positionable active layer.

4. The optical shutter array system as recited in claim 3, wherein:

the plurality of collimator features increase a probability of the light exiting the positionable active layer being emitted by the optical shutter, wherein the plurality of collimator features are configured to interact with the light that approach a vicinity of an interface between the external surface of the positionable active layer and the plurality of collimator features causing the light to enter and traverse the plurality of collimator features and exit the optical shutter.

5. The optical shutter array system as recited in claim 4, wherein optical properties of the plurality of collimator features are configured to direct the light that traverse the plurality of collimator features to exit external surfaces of the plurality of collimator features in a direction more nearly perpendicular to the external surface of the positionable active layer.

7. The optical shutter array system as recited in claim 3, wherein the collimator features increase a probability of the light exiting the positionable active layer being emitted by the optical shutter.

8. The optical shutter array system as recited in claim 3, wherein the plurality of collimator features change an angle of the light emitting from the at least one optical shutter.

9. The optical shutter array system as recited in claim 3, wherein optical properties of the plurality of collimator features are configured to direct the light that traverse the plurality of collimator features to exit external surfaces of the plurality of collimator features in a direction more nearly perpendicular to the external surface of the positionable active layer.

10. An optical shutter comprising:

a light guide through which light propagates via total internal reflection;

a positionable active layer configured to physically move between an on state position and an off state position, the positionable active layer located in proximity to the light guide, the positionable active layer having an internal surface that faces the light guide and an external surface that faces away from the light guide; and

a first set of collector-coupler features on the internal surface of the positionable active layer, wherein during the on state position, when the optical shutter is activated to emit the light, the light is caused to exit the light guide and enter the positionable active layer via the first set of collector-coupler features.

11. The optical shutter as recited in claim 10, wherein during the on state position, when the optical shutter is activated to emit the light, the positionable active layer is positioned such that distal ends of the first set of collector-coupler features are compressed onto a surface of the light guide so as to cause the light to exit the light guide and enter the positionable active layer via the first set of collector-coupler features, wherein the distal ends are elastically deformed in such a manner as to build potential energy within the first set of collector-coupler features.

12. The optical shutter as recited in claim 10, wherein the first set of collector-coupler features comprises microlenses, the microlenses comprising at least one of a:

pyramidal frustum;

conical frustum;

compound parabolic;

compound elliptical; and

polyobject.

13. The optical shutter as recited in claim 10, wherein an opaque material is disposed interstitially between the collector-coupler features of the first set of collector-coupler features,

the opaque material comprises a conformal coating of the collector-coupler features and interstitial spaces between the collector-coupler features except for apertures of each of the collector-coupler features which are uncoated so that light can enter the positionable active layer via the apertures when the positionable active layer is in the on state position, or the opaque material substantially fills the interstitial spaces between the collector-coupler features;

and

the opaque material does not contact any surface of the light guide when in the on state position.

14. An optical shutter comprising:

a light guide through which light propagates via total internal reflection;

a positionable active layer configured to physically move between an on state position and an off state position, the positionable active layer located in proximity to the light guide;

a plurality of collimator features on an external surface of the positionable active layer that increase a probability of the light exiting the positionable active layer being emitted by the optical shutter; and

a first set of collector-coupler features on an internal surface of the positionable active layer.

15. The optical shutter as recited in claim 14, wherein during the on state position, when the optical shutter is activated to emit the light, the positionable active layer is positioned such that distal ends of the first set of collector-coupler features are compressed onto a surface of the light guide so as to cause the light to exit the light guide and enter the positionable active layer via the first set of collector-coupler features, wherein the distal ends are elastically deformed in such a manner as to build potential energy within the first set of collector-coupler features.

16. The optical shutter as recited in claim 14, wherein an opaque material is disposed interstitially between the collector-coupler features of the first set of collector-coupler features.

17. The optical shutter as recited in claim 16, wherein the opaque material is electrically conductive.

18. The optical shutter as recited in claim 16, wherein the opaque material is color absorbing.

19. The optical shutter as recited in claim 16, wherein the opaque material is reflective.

20. The optical shutter as recited in claim 14, wherein the first set of collector-coupler features comprises microlenses.

21. The optical shutter as recited in claim 20, wherein the microlenses comprise at least one of a:

pyramidal frustum;

conical frustum;

compound elliptical; and

polyobject.

22. An optical shutter array system comprising:

a plurality of optical shutters on a display, wherein at least one of the plurality of optical shutters comprises;

a light guide through which light propagates via total internal reflection;

a positionable active layer configured to physically move between an on state position and an off state position, the positionable active layer located in proximity to the light guide;

a plurality of collimator features on an external surface of the positionable active layer; and

a first set of collector-coupler features on an internal surface of the positionable active layer.

23. The optical shutter array system as recited in claim 22, wherein optical properties of each collector-coupler feature of the first set of collector-coupler features are configured such that the light entering the collector-coupler feature from the light guide hit a side boundary of the collector-coupler feature under conditions sufficient for total internal reflection within the collector-coupler feature before the light hit an interface between the collector-coupler feature and the internal surface of the positionable active layer.

24. The optical shutter array system as recited in claim 22, wherein during the on state position of the at least one optical shutter, when the at least one optical shutter is activated to emit the light, the positionable active layer is positioned such that distal ends of the first set of collector-coupler features are compressed onto a surface of the light guide so as to cause the light to exit the light guide and enter the positionable active layer via the first set of collector-coupler features, wherein the distal ends are elastically deformed in such a manner as to build potential energy within the first set of collector-coupler features.

25. The optical shutter array system as recited in claim 22, wherein upon transitioning the at least one optical shutter from the on state to the off state, when the at least one optical shutter is inactivated to thereby not emit the light, the first set of collector-coupler features decompress and release the potential energy in a form of a separation force that assists in moving the first set of collector-coupler features away from the surface of the light guide to overcome stiction between the surface of the light guide and the first set of collector-coupler features.

26. The optical shutter array system as recited in claim 22, further comprising a layer of compliant material, positioned adjacent to the first set of collector-coupler features, wherein compression of the first set of collector-coupler features causes elastic compression of the layer of compliant material in such a manner as to build potential energy within the layer of compliant material.

27. The optical shutter array system as recited in claim 26, wherein upon transitioning the at least one optical shutter from the on state to the off state, the layer of compliant material is configured to decompress and release the potential energy in a form of a restorative force that assists in moving the first set of collector-coupler features away from the surface of the light guide to overcome stiction between the surface of the light guide and the first set of collector-coupler features.

28. The optical shutter array system as recited in claim 22, wherein an opaque material is disposed interstitially between the collector-coupler features of the first set of collector-coupler features.

29. The optical shutter array system as recited in claim 28, wherein the opaque material is electrically conductive.

30. The optical shutter array system as recited in claim 28, wherein the opaque material is color absorbing.

31. The optical shutter array system as recited in claim 28, wherein the opaque material is reflective.

32. The optical shutter array system as recited in claim 28, wherein the first set of collector-coupler features comprises microlenses.

33. The optical shutter array system as recited in claim 32, wherein the microlenses comprise at least one of a:

pyramidal frustum;

conical frustum;

compound parabolic;

compound elliptical; and

polyobject.