Optical component array having adjustable curvature

• US 9,442,285 B2
• Filed: 01/12/2012
• Issued: 09/13/2016
• Est. Priority Date: 01/14/2011
• Status: Active Grant

• Current Assignee: Board of Trustees of The University of Illinois
• Original Assignee: Board of Trustees of The University of Illinois
• Inventors: Rogers, John A.
• Primary Examiner(s): LUU, THANH X
• Application Number:
  US13/349,336
• Publication Number:
  US 20120261551A1
• Time in Patent Office: 1,706 Days
• Field of Search: 250/208.1
• US Class Current: 1/1
• CPC Class Codes: G02B 26/0825 the reflecting element being a flexible sheet or membrane, e.g. for varying the focus flexible mirrors for cosmetic use A45D42/24
• CPC Class Codes: G02B 26/0875 by means of one or more refracting elements
• CPC Class Codes: G02B 27/28 for polarising used in stereoscopes G02B30/25
• CPC Class Codes: G02B 3/14 of variable focal length

Abstract

Provided are devices, and related methods, for controlling curvature of an array of optical components on, embedded, or partially embedded in, a deformable substrate. The array of optical components, in an aspect, comprises a deformable substrate having a contact surface and an array of mechanically interconnected optical components supported by the contact surface. An actuator is operably connected to the contact surface, wherein the actuator variably controls a curvature of said contact surface. The contact surface may have a curvature that spans concave to convex, which is tunable. In an aspect, the array of optical components is part of an optical device, such as a camera with a continuously adjustable zoom whose focus is maintained by adjusting a photodetector array curvature. In an aspect, the method is adjusting the curvature of a substrate that supports the array of optical components by applying a force to the substrate.

Claims

1. An imaging system comprising:

a deformable substrate having a contact surface, wherein said deformable substrate is an elastomeric membrane;

an array of mechanically interconnected optical components supported by said contact surface, wherein said optical components comprise photodiodes that form a photodetector array;

an encapsulating layer supported by said deformable substrate, wherein the encapsulating layer at least partially encapsulates said array of mechanically interconnected optical components;

an actuator operably connected to said contact surface, wherein said actuator is configured to continuously adjust a curvature of said contact surface, wherein change of curvature by the actuator is reversible;

a dynamically tunable and adjustable curvature lens in optical communication with said photodetector array; and

a processor for calculating a Petzval surface of an object imaged by said dynamically tunable and adjustable curvature lens, wherein said actuator is configured to generate curvature of said photodetector that substantially matches the calculated Petzval surface,

thereby providing a dynamically tunable imaging system having a continuously adjustable zoom and correspondingly continuously adjustable photodetector array surface curvature configured to match the Petzval surface formed by a change in curvature of said dynamically tunable and adjustable curvature lens.

2. The array of optical components of claim 1, wherein said deformable substrate has a thickness that is less than 1 mm.

3. The array of optical components of claim 1, wherein said optical component is selected from the group consisting of:

optical detectors;

optical emitters;

optical reflectors;

photovoltaics;

lenses;

filters; and

polarizers.

4. The array of optical components of claim 3, wherein said array of mechanically interconnected optical components comprise photodiodes.

5. The array of optical components of claim 1, wherein said actuator selected from the group consisting of:

a piezoelectric actuator;

an electrostatic actuator; and

a magnetic actuator.

6. The array of optical components of claim 1, wherein said actuator is selected from the group consisting of:

a hydraulic system;

a pneumatic system;

a mechanical actuator; and

a force generator that is integrated with said deformable substrate.

7. The array of optical components of claim 6, wherein said integrated force generator is a shape memory polymer or metal.

8. The array of optical components of claim 6, wherein said mechanical actuator comprises an array of mechanical actuators positioned on a back surface that is opposed to said contact surface.

9. The array of optical components of claim 6, wherein said hydraulic or pneumatic system comprises:

an optical component fluid chamber, wherein said deformable substrate forms a surface of said optical component fluid chamber; and

a pressure controller for controlling a pressure of said optical component fluid chamber.

10. The array of optical components of claim 9, wherein said fluid chamber pressure is controlled by introducing or removing a fluid to said fluid chamber by said actuator.

11. The array of optical components of claim 9, wherein said fluid chamber is positioned adjacent to a back surface of said deformable substrate, wherein said back surface is opposed and separated from said contact surface by said deformable membrane.

12. The array of optical components of claim 1, wherein said array of optical components comprises a plurality of islands, wherein each island is mechanically or electrically connected to an adjacent island by an interconnect, wherein said interconnect is in a buckled or a serpentine configuration.

13. The array of optical components of claim 1, wherein said curvature can range from a concave to a convex configuration, wherein said array of optical components remain functional over the concave to convex configuration.

14. The array of optical components of claim 13, wherein curvature is defined by a radius of curvature, and said radius of curvature can vary from 0.1 mm to flat in the concave or the convex configuration.

15. The array of optical components of claim 1, wherein said actuator provides a curvature that is within 5% of a desired curvature.

16. The array of optical components of claim 1, said deformable substrate having a spatially-varying material property that influences the curvature of the contact surface.

17. The imaging system of claim 1, wherein said dynamically tunable and adjustable curvature lens comprises an elastomeric lens membrane.

18. The imaging system of claim 17, wherein said dynamically tunable and adjustable curvature lens is a tunable fluidic lens further comprising:

a lens fluid chamber having one surface formed by said elastomeric lens membrane; and

an optical component fluid chamber having one surface formed by said deformable substrate;

wherein the actuator controls;

a pressure in said lens fluid chamber to tune said elastomeric lens membrane; and

a pressure in said optical component fluid chamber to tune said photodetector array.

19. The imaging system of claim 18, wherein said actuator comprises:

a lens fluid chamber actuator for controlling said pressure in said lens fluid chamber; and

an optical component fluid chamber actuator for controlling said pressure in said optical component fluid chamber.

20. The imaging system of claim 18, wherein said actuator comprises one or more actuators to independently vary a radius of curvature of said elastomeric lens membrane and said deformable substrate.

21. The imaging system of claim 20, wherein said actuator is a single actuator that adjusts curvature of both said elastomeric lens and said photodetector array.

22. The imaging system of claim 1 having a continuously adjustable zoom, wherein said zoom is greater than or equal to a factor of 1 and less than or equal to a factor of 50.

23. The array of optical components of claim 1, wherein adjacent mechanically interconnected optical components are interconnected by a serpentine or buckled interconnect.

24. The array of optical components of claim 23, wherein the encapsulating layer comprises a top and bottom film of polyimide and the interconnects are metal lines encapsulated with the top and bottom film of polyimide, wherein the top film, bottom film, or both films of polyimide have a thickness less than or equal to 1 μ

m.

25. The imaging system of claim 1, wherein the encapsulating layer provides a neutral mechanical plane to isolate a rigid material of the array from bending-induced strain.

26. The imaging system of claim 25, wherein the rigid material of the array is a metal or semiconductor element.

27. The imaging system of claim 1, wherein each photodetector of the photodetector array has an area that is less than 0.25 mm².

28. The imaging system of claim 1, wherein the photodetector array surface curvature is within 5% of the Petzval surface averaged over the entire photodetector array surface.

29. A method of controlling curvature of an array of optical components comprising:

providing an array of mechanically interconnected optical components on a contact surface of a deformable substrate, wherein said deformable substrate is an elastomeric membrane and said optical components comprise photodiodes that form a photodetector array;

providing an encapsulating layer supported by said deformable substrate, wherein the encapsulating layer at least partially encapsulates said array of mechanically interconnected optical components;

providing a tunable lens comprising a dynamically tunable and adjustable curvature lens in optical communication with said photodetector array; and

exerting a force on said dynamically tunable and adiustable curvature lens to provide a continuously adiustable zoom lens forming an image at said photodetector array;

determining a Petzval surface of said image formed at said photodetector array; and

exerting a force on the deformable substrate to continuously adjust the curvature of the photodetector array to match the Petzval surface formed by said dynamically tunable and adiustable curvature lens, wherein the deformation is reversible,

thereby providing a dynamically tunable imaging system having a continuously adjustable zoom lens having an image at said photodetector array that is in focus by adjusting said photodetector array curvature to match the Petzval surface formed by said dynamically tunable and adjustable curvature lens.

30. The method of claim 29, wherein said force is exerted by:

activating an actuator that is operably connected to said deformable substrate.

31. The method of claim 29, wherein said force is exerted by the deformable substrate or an actuator positioned in or on the deformable substrate.

32. The method of claim 29 wherein said photodetector array comprises a plurality of mechanically interconnected photodiodes.

33. The method of claim 32, further comprising the steps of:

adjusting a curvature of said dynamically tunable and adjustable curvature lens to obtain a desired optical zoom of an object positioned in said lens field of view;

determining an ideal curvature of said photodetector array to provide a focused image of light from the object transmitted through said dynamically tunable and adjustable curvature lens; and

adjusting said exerted force on said deformable substrate to substantially match the photodetector array curvature to said ideal curvature;

thereby obtaining an in focus image of said object for any optical zoom value.

34. The method of claim 33, further comprising:

determining an ideal separation distance between said photodetector and said dynamically tunable and adjustable curvature lens for capturing said focused image by said photodetector; and

adjusting a separation distance between said dynamically tunable and adjustable curvature lens and said photodetector to substantially match said separation distance to said ideal separation distance.

35. The method of claim 33, wherein the desired optical zoom corresponds to a zoom factor that is greater than or equal to 1 and less than or equal to 100 and the optical image at the photodetector is in focus for all zoom factor values without additional lenses between the dynamically tunable and adjustable curvature lens and the photodetector.

36. The method of claim 33, wherein the ideal curvature is determined computationally or empirically.

37. The method of claim 29, wherein at least a central portion of the deformable substrate has a curvature that is hemispherical or paraboloid.

38. The method of claim 29, wherein said array of optical components maintain functionality over a range of membrane curvatures, corresponding to concave, convex, or planar configurations, or a radius of curvature range that is between flat and 0.1 mm.

39. The method of claim 29, further comprising the step of calibrating the optical components to address the position of individual optical components of the array over a range of membrane curvatures.

40. The method of claim 39, wherein the calibrating is by determining the pitch or inter-component spacing for a plurality of membrane curvatures computationally or empirically using a known image provided at a defined distance.

41. The method of claim 33, wherein the ideal curvature corresponds to a Petzval surface formed by transmission of electromagnetic radiation through the dynamically tunable and adjustable curvature lens.

42. The method of claim 29, wherein adjacent mechanically interconnected optical components are interconnected by a serpentine or buckled interconnect.

43. The method of claim 42, wherein the encapsulating layer comprises a top and bottom film of polyimide and the interconnects are metal lines encapsulated within the top and bottom film of polyimide, wherein the top film, bottom film, or both films of polyimide have a thickness less than or equal to 1 μ

m.

44. The method of claim 29, wherein the encapsulating layer provides a neutral mechanical plane to isolate a rigid material of the array from bending-induced strain.

45. The method of claim 44, wherein the rigid material of the array is a metal or semiconductor element.

46. The method of claim 29, wherein the each photodetector of the photodetector array has an area that is less than 0.25 mm².

47. The method of claim 29, wherein the photodetector array surface curvature is within 5% of the Petzval surface averaged over the entire photodetector array surface.