Liquid lens with piezoelectric voltage converter

• US 20070146894A1
• Filed: 12/27/2005
• Published: 06/28/2007
• Est. Priority Date: 12/27/2005
• Status: Active Grant

• Current Assignee: Tessera, Inc. (Adeia Inc.)
• Original Assignee: Tessera, Inc. (Adeia Inc.)
• Inventors: Humpston, Giles
• Granted Patent: US 7,443,597 B2
• Time in Patent Office: Days
• US Class Current: 359/666
• CPC Class Codes: G02B 26/005 based on electrowetting
• CPC Class Codes: G02B 3/14 of variable focal length
• CPC Class Codes: H01L 27/14618 Containers
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof
• CPC Class Codes: H04N 23/57 Mechanical or electrical details of cameras or camera modules specially adapted for being embedded in other devices

Abstract

An electronic camera module includes a lens or refractive element formed by a pair of immiscible liquids and having optical properties which can be varied by applying a voltage so as to deform the meniscus. One of the two liquids extends from the meniscus all the way to the front surface of the sensor, so that light passing through the meniscus does not encounter further changes in refractive index enroute to the sensor.

Claims

1. A variable optical element comprising:

(a) a lens including a first liquid, a second liquid having an index of refraction different from said first liquid, a structure defining a space containing said liquids, and control electrodes in proximity to said first and second liquids, said first and second liquids forming a meniscus therebetween, said electrodes and said liquids being arranged so that the curvature of said meniscus can be altered by varying an electrical potential between said electrodes; and

(b) a piezoelectric transformer including a primary piezoelectic element and a secondary piezoelectric element mechanically linked to said primary piezoelectric element, said secondary piezoelectric element being electrically connected to said control electrodes.

2. The variable optical element of claim 1 wherein said piezoelectric transformer has a step-up ratio of about 10:

1 to about 100;

1.

3. The variable optical element of claim 1 wherein said secondary piezoelectric element is directly attached to said primary piezoelectric element.

4. The variable optical element of claim 3 further comprising a structure containing said liquids, said control electrodes being mounted to said structure.

5. An optical module including the variable optical element of claim 4, wherein said piezoelectric transformer is mechanically connected to said structure.

6. The module of claim 5 further comprising lens control terminals electrically connected to said primary piezoelectric element.

7. The module of claim 6 wherein said lens control terminals are carried on said piezoelectric transformer.

8. The module of claim 6 wherein said lens control terminals are carried on said structure.

9. A camera module comprising a variable optical element as claimed in claim 1, and an optoelectronic sensor, mechanically connected to said structure.

10. The camera as claimed in claim 9 further comprising lens control terminals electrically connected to said primary piezoelectric element.

11. The camera module of claim 10 wherein said optoelectronic sensor includes a semiconductor chip incorporating a plurality of optically sensitive elements and a cover overlying said chip and defining a front surface.

12. The camera module of claim 10 wherein said lens control terminals are carried on said cover.

13. The camera module of claim 12 further comprising sensor terminals carried on said cover and electrically connected to said semiconductor chip.

14. The camera module of claim 13 wherein said cover has an inner surface facing toward said chip and an outer surface facing away from said chip, said sensor terminals and said lens control terminals being exposed at said outer surface of said cover.

15. The camera module of claim 10 wherein said structure includes a container wall projecting from said outer surface and extending away from said chip, said container wall at least partially defining said space.

16. The camera module of claim 15 wherein at least one of said control electrodes is mounted to said container wall.

17. The camera module of claim 15 wherein said optoelectronic sensor includes a semiconductor chip incorporating a plurality of optically sensitive elements and a cover overlying said chip and defining a front surface. wherein said container wall projects in a central region of said front surface and said lens control terminals are disposed in a peripheral region of said front surface outside of said central region, the module further comprising sensor terminals disposed in said peripheral region of said front surface and electrically connected to said chip.

18. The camera module of claim 17 wherein said terminals are adapted for surface-mounting to a circuit panel.

19. A digital camera comprising:

(a) a lens assembly including a first liquid, a second liquid having an index of refraction different from said first liquid, control electrodes in proximity to said first and second liquids, and a structure containing said liquids, said first and second liquids forming a meniscus therebetween, said electrodes and said liquids being arranged so that the curvature of said meniscus can be altered by varying an electrical potential between said electrodes;

(b) a piezoelectric transformer including a primary piezoelectic element and a secondary piezoelectric element mechanically linked to said primary piezoelectric element, said secondary piezoelectric element being electrically connected to said control electrodes; and

(c) an optoelectronic sensor mounted in a preselected spatial relationship to the structure.

20. The digital camera of claim 19, further comprising a circuit panel, said optoelectronic sensor, said container structure and said piezoelectric transformer being mechanically connected to said circuit panel.

21. The digital camera of claim 20 wherein said transformer is mounted to said sensor and mechanically connected to said circuit panel by said sensor.

22. The digital camera of claim 20 wherein said transformer is mounted to said structure and mechanically connected to said circuit panel by said structure.

23. The digital camera of claim 20 wherein said transformer is mounted directly to said circuit panel.

24. The digital camera of claim 20 wherein said optoelectronic sensor, lens assembly, and piezoelectric transformer occupy an area of said circuit panel about twice the frontal area of said sensor or less.

25. The digital camera of claim 20 wherein said piezoelectric transformer is at least partially aligned with said sensor in horizontal directions parallel to said circuit panel.

26. The digital camera of claim 20 wherein said circuit panel has oppositely-directed front and rear sides, said optoelectronic sensor is disposed to the rear of said circuit panel and said lens assembly is disposed at least partially in front of said circuit panel.

27. The digital camera of claim 26 wherein said piezoelectric transformer is disposed at least partially in front of said circuit panel, said lens assembly projects forwardly from said circuit panel by a first distance, and said piezoelectric transformer projects forwardly from said circuit panel by a second distance less than said first distance.

28. A sensor module comprising:

(a) an optoelectronic sensor including a body having a front surface and an array of optically sensitive elements arranged so that light impinging on said front surface will pass to said optically sensitive elements, said sensor further including circuitry connected to said optically sensitive elements;

(b) a piezoelectric transformer including a primary piezoelectic element and a secondary piezoelectric element mechanically linked to said primary piezoelectric element, said secondary piezoelectric element having a pair of secondary electrodes, said piezoelectric transformer being mechanically connected to said optoelectronic sensor; and

(c) terminals mechanically connected to said transformer and said sensor, at least some of said terminals being electrically connected to said primary piezoelectric element and at least some of said terminals being electrically connected to said circuitry.

29. The sensor module as claimed in claim 28 further comprising a module substrate, said transformer and said sensor being mounted on said module substrate, at least some of said terminals being carried on said module substrate.

30. The sensor module as claimed in claim 29 wherein some of said terminals are carried on said sensor.

31. The sensor module as claimed in claim 28 wherein said terminals are adapted for surface mounting to a circuit panel.

32. The sensor module as claimed in claim 28 wherein said sensor body includes a chip having said sensors and said circuitry and a cover overlying a surface of said chip, and wherein said terminals are carried by said cover.

33. The sensor module as claimed in claim 28 wherein said sensor body includes a chip having said sensors and said circuitry and wherein said terminals are carried by said chip.