Optical lens displacement systems

• US 20100033835A1
• Filed: 12/10/2007
• Published: 02/11/2010
• Est. Priority Date: 03/21/2005
• Status: Active Grant

• Current Assignee: Bayer Materialscience AG (Covestro AG)
• Original Assignee: Artificial Muscle, Inc. (Covestro AG)
• Inventors: Hui, Otto, Zarrabi, Alireza, Heim, Jonathan R., Polyakov, Ilya
• Granted Patent: US 8,054,566 B2
• Time in Patent Office: Days
• US Class Current: 359/683
• CPC Class Codes: F04B 43/0054 particularities of the flexible members
• CPC Class Codes: F04B 43/04 Pumps having electric drive
• CPC Class Codes: G02B 13/001 Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras G02B23/243 takes precedence
• CPC Class Codes: G02B 7/102 controlled by a microcomputer cameras with interchangeable lenses G03B17/14
• CPC Class Codes: H02N 1/002 Electrostatic motors
• CPC Class Codes: H04R 19/02 Loudspeakers H04R19/01 takes precedence

Abstract

The present invention provides optical systems, devices and methods which utilize one or more electroactive polymer actuators to adjust an optical parameter of the optical device or system.

Claims

1. A lens displacement system comprising:

a lens unit comprising at least one lens positioned along a focal axis, the lens unit having a linear bearing surface;

an electroactive polymer actuator positioned adjacent the lens unit wherein activation of the actuator moves the lens unit along the focal axis; and

a linear guide adjacent to the linear bearing surface for maintaining the position of the lens unit.

2. The lens displacement system of claim 1, further comprises a biasing mechanism for biasing the lens unit along the focal axis.

3. The lens displacement system of claim 2, wherein biasing of the lens unit stretches a diaphragm of the electroactive polymer actuator into a frustum form.

4. The lens displacement system of claim 2, wherein the biasing mechanism comprises a coil spring encircling the lens unit, and wherein the linear guide is positioned between the coil spring and an outer surface of the lens unit.

5. The lens displacement system of claim 1, wherein the linear guide is a bushing wall extending from a housing which at least partially encases the lens unit.

6. The lens displacement system of claim 1, wherein the linear guide comprises at least one guide rail extending parallel to the focal axis.

7. The lens displacement system of claim 6, wherein the lens unit comprises a platform having an opening therein for receiving the at least one guide rail.

8. The lens displacement system of claim 2, wherein the biasing mechanism comprises a leaf spring mechanism positioned between the linear guide and an outer surface of the lens unit.

9. The lens displacement system of claim 8, wherein the leaf spring mechanism has a base ring encircling the lens unit and a plurality of radially extending tabs engaged against a surface of the electroactive actuator.

10. The lens displacement system of claim 2, wherein the biasing mechanism is integrally formed with the lens unit.

11. The lens displacement system of claim 10, wherein the biasing mechanism is further integrally formed with a housing which at least partially encases the lens unit.

12. The lens displacement system of claim 2, wherein the biasing mechanism comprises an annular diaphragm extending between the lens unit and the housing, wherein the diaphragm has a negative rate spring bias.

13. The lens displacement system of claim 12, wherein the diaphragm comprises a low viscosity elastomer material.

14. The lens displacement system of claim 2, wherein the biasing mechanism comprises at least two spring tabs extending between the lens unit and the housing.

15. The lens displacement system of claim 1, wherein movement of the lens unit changes the focal length of the lens unit.

16. The lens displacement system of claim 1, wherein the at least one lens is a focusing lens.

17. The lens displacement system of claim 1, wherein movement of the lens unit changes the magnification of the lens unit.

18. The lens displacement system of claim 1, wherein the lens unit is carried by a lens driver mechanism whereby activation of the actuator moves the lens driver mechanism.

19. The lens displacement system of claim 18, wherein the lens unit comprises an afocal lens assembly.

20. The lens displacement system of claim 19, comprising multiple lens stages, each stage comprising a lens, wherein the lens driver mechanism translates the multiple stages at different rates.

21. The lens displacement system of claim 20, wherein the ratio of a translation rate of one lens stage to that of another lens stage defines a telescoping action.

22. The lens displacement system of claim 20, wherein each lens is seated within a lens plate carried by the lens driver mechanism.

23. The lens displacement system of claim 22, wherein the lens driver mechanism further comprises a pair of linkages extending between lens plates.

24. The lens displacement system of claim 1, further comprising a backstop to prevent movement of the lens unit beyond an infinity focus position.

25. The lens displacement system of claim 1, further comprising at least one light filter along the focal axis.

26. The lens displacement system of claim 1, further comprising a translucent cover over a forward end of the lens unit.

27. The lens displacement system of claim 1, wherein the lens unit configured for calibrating the focus of the lens unit.

28. The lens displacement system of claim 27, wherein a housing portion of the lens unit comprises at least one indentation for receiving a calibration tool.

29. The lens displacement system of claim 1, further comprising a sensor for sensing the position of the lens unit.

30. The lens displacement system of claim 29, wherein the sensor comprises a pair of spaced apart electrodes, the first electrode positioned on an outer surface of the lens unit and the second electrode positioned on a surface of the linear guide facing the outer surface of the lens unit, wherein position of the lens unit relative to linear guide changes the capacitance across the electrodes.

31. The lens displacement system of claim 1, further comprising a heating element positioned for controlling the temperature of a least a portion of the electroactive polymer actuator.

32. The lens displacement system of claim 1, wherein the lens unit has a cylindrical barrel configuration and the linear bearing surface is an outer surface of the lens barrel.

33. The lens displacement system of claim 1, wherein the lens unit comprises a plurality of lenses, wherein a distal most lens is a focusing lens and two or more lenses proximal thereto are afocal lenses.

34. The lens displacement system of claim 1, wherein the electroactive polymer actuator comprises a film wherein the film is configured to deflect in only one direction when activated.

35. The lens displacement system of claim 34, wherein the film comprises an elastomeric dielectric layer bonded to a backing material, the backing material having a higher elastic modulus than the dielectric layer.

36. A lens displacement system comprising:

a lens unit comprising at least one lens positioned along a focal axis, wherein in the lens unit is biased in the infinity direction;

a backstop to prevent movement of the lens unit in the macro direction beyond an initial macro position; and

an electroactive polymer actuator positioned adjacent the lens unit wherein activation of the actuator moves the lens unit along the focal axis toward an infinity position.

37. A lens displacement system comprising:

a lens unit comprising at least one lens positioned and movable along a focal axis in opposing directions; and

a two-phase electroactive polymer actuator positioned adjacent the lens unit wherein activation of the actuator moves the lens unit along the focal axis, wherein the actuator comprises to oppositely facing frustum shaped diaphragms which bias each other.

38. The lens displacement system of claim 37, comprising a plurality of two-phase electroactive polymer actuators stacked in series.

39. The lens displacement system of claim 38, wherein adjacent actuators are biased apart by a spring.

40. The lens displacement system of claim 39, wherein the concave sides of the frustum diaphragms face each other.

41. The lens displacement system of claim 40, wherein the convex sides of the frustum diaphragms face each other.

42. A lens displacement system comprising:

a lens unit comprising at least one lens positioned along a focal axis; and

an electroactive polymer actuator positioned adjacent the lens unit wherein activation of the actuator moves the lens unit along the focal axis, the actuator comprising an electroactive polymer film wherein the film deflects in only one direction when activated.

43. The lens displacement system of claim 42, wherein the film comprises an elastomeric dielectric layer bonded to a backing material, the backing material having a higher elastic modulus than the dielectric layer.

44. The lens displacement system of claim 42, wherein the actuator further comprises a fixed base member wherein the film extends between the lens unit and the base member.

45. The lens displacement system of claim 44, wherein the film has an arched configuration, wherein the backing material is on the concave side of the film.

46. The lens displacement system of claim 44, wherein the film has a folded configuration.

47. A lens displacement system comprising:

a lens unit comprising at least one lens positioned along a focal axis; and

an electroactive polymer actuator positioned adjacent the lens unit wherein activation of the actuator moves the lens unit along the focal axis, the actuator comprising an electrode arrangement configured for generating heat.

48. The lens displacement system of claim 47, wherein the electrode arrangement is in series.

49. The lens displacement system of claim 47, wherein the electrode arrangement is in parallel.

50. A lens displacement system comprising:

a lens unit comprising at least one lens positioned along a focal axis;

an electroactive polymer actuator positioned adjacent the lens unit wherein activation of the actuator moves the lens unit along the focal axis, the actuator comprising an electroactive polymer film; and

a heating element positioned adjacent to and having a profile which matches that of the electroactive polymer film.

51. The lens displacement system of claim 50, wherein the heating element has a frustum shape.