Liquid lens with piezoelectric voltage converter

• US 7,443,597 B2
• Filed: 12/27/2005
• Issued: 10/28/2008
• Est. Priority Date: 12/27/2005
• Status: Expired due to Fees

• Current Assignee: Tessera, Inc. (Adeia Inc.)
• Original Assignee: Tessera, Inc. (Adeia Inc.)
• Inventors: Humpston, Giles
• Primary Examiner(s): SCHWARTZ, JORDAN MARC
• Application Number:
  US11/318,821
• Publication Number:
  US 20070146894A1
• Time in Patent Office: 1,036 Days
• Field of Search: 359665-666
• US Class Current: 359/665
• 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 piezoelectric element and a secondary piezoelectric element mechanically linked to said primary piezoelectric element, said secondary piezoelectric element being electrically connected to said control electrodes, said piezoelectric transformer being arranged to convert a primary electrical signal applied to said primary piezoelectric element into mechanical motion and to convert the mechanical motion into a secondary electrical signal in said secondary piezoelectric element, whereby said secondary electrical signal will be applied to said control electrodes, and wherein said piezoelectric transformer has a step-up ratio of about 10;

1 to about 100;

1.

2. The An optical module including 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;

(b) a piezoelectric transformer including a primary piezoelectric element and a secondary piezoelectric element mechanically linked to said primary piezoelectric element, said secondary piezoelectric element being electrically connected to said control electrodes, said piezoelectric transformer being arranged to convert a primary electrical signal applied to said primary piezoelectric element into mechanical motion and to convert the mechanical motion into a secondary electrical signal in said secondary piezoelectric element, whereby said secondary electrical signal will be applied to said control electrodes, and wherein said secondary piezoelectric element is directly attached to said primary piezoelectric element;

(c) a structure containing said liquids, said control electrodes being mounted to said structure and wherein said piezoelectric transformer is mechanically connected to said structure; and

(d) lens control terminals electrically connected to said primary piezoelectric element.

3. The module of claim 2 wherein said lens control terminals are carried on said piezoelectric transformer.

4. The module of claim 2 wherein said lens control terminals are carried on said structure.

5. A camera module comprising a variable optical element as claimed in claim 2, and an optoelectronic sensor, mechanically connected to said structure.

6. The camera as claimed in claim 5 further comprising lens control terminals electrically connected to said primary piezoelectric element.

7. The camera module of claim 6 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.

8. The camera module of claim 7 wherein said lens control terminals are carried on said cover.

9. The camera module of claim 8 further comprising sensor terminals carried on said cover and electrically connected to said semiconductor chip.

10. The camera module of claim 9 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.

11. 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.

12. The camera module of claim 11 wherein at least one of said control electrodes is mounted to said container wall.

13. The camera module of claim 11 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.

14. The camera module of claim 13 wherein said terminals are adapted for surface-mounting to a circuit panel.

15. 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 piezoelectric element and a secondary piezoelectric element mechanically linked to said primary piezoelectric element, said secondary piezoelectric element being electrically connected to said control electrodes, said piezoelectric transformer being arranged to convert a primary electrical signal applied to said primary piezoelectric element into mechanical motion and to convert the mechanical motion into a secondary electrical signal in said secondary piezoelectric element, whereby said secondary electrical signal will be applied to said control electrodes;

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

(d) a circuit panel, said optoelectronic sensor, said container structure and said piezoelectric transformer being mechanically connected to said circuit panel, and wherein said transformer is mounted to said sensor and mechanically connected to said circuit panel by said sensor.

16. The digital camera of claim 15 wherein said transformer is mounted to said structure and mechanically connected to said circuit panel by said structure.

17. The digital camera of claim 15 wherein said transformer is mounted directly to said circuit panel.

18. The digital camera of claim 15 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.

19. The digital camera of claim 15 wherein said piezoelectric transformer is at least partially aligned with said sensor in horizontal directions parallel to said circuit panel.

20. The digital camera of claim 15 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.

21. The digital camera of claim 20 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.