MEMS Auto Focus Miniature Camera Module with Fixed and Movable Lens Groups

• US 20130293764A1
• Filed: 05/06/2013
• Published: 11/07/2013
• Est. Priority Date: 03/10/2012
• Status: Active Grant

• Current Assignee: DigitalOptics Corporation (Adeia Inc.)
• Original Assignee: DigitalOptics Corporation (Adeia Inc.)
• Inventors: Lipson, Ariel, Kinrot, Uri, Bahar, Dalit, Kriman, Moshe, Levy, Moshe, Ward, Ocie, Harland, Mark
• Granted Patent: US 9,294,667 B2
• Time in Patent Office: Days
• US Class Current: 348/345
• 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 13/009 having zoom function
• CPC Class Codes: G02B 7/08 adapted to co-operate with a remote control mechanism
• CPC Class Codes: G02B 7/09 adapted for automatic focusing or varying magnification
• CPC Class Codes: G02B 7/10 by relative axial movement of several lenses, e.g. of varifocal objective lens
• CPC Class Codes: G02B 7/282 Autofocusing of zoom lenses
• CPC Class Codes: G03B 2205/0046 Movement of one or more optical elements for zooming
• CPC Class Codes: G03B 2205/0053 Driving means for the movement of one or more optical element
• CPC Class Codes: G03B 3/10 Power-operated focusing
• CPC Class Codes: H04N 23/51 Housings
• CPC Class Codes: H04N 23/57 Mechanical or electrical details of cameras or camera modules specially adapted for being embedded in other devices
• CPC Class Codes: H04N 23/67 Focus control based on electronic image sensor signals
• CPC Class Codes: H04N 23/69 Control of means for changing angle of the field of view, e.g. optical zoom objectives or electronic zooming
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

A MEMS auto focus miniature camera module includes an image sensor and an optical train including at least one movable lens and one or more fixed lenses or fixed lens groups on either side of the movable lens. The movable lens provides an auto focus feature of the camera module. A MEMS actuator translates the movable lens through an auto focus range to adjust focus.

Claims

1. An auto focus zoom camera module, comprising:

a camera module housing;

an image sensor within the housing

an optical train within the housing including multiple lenses configured to provide auto focus and zoom for the camera module, including a first fixed lens group, a second fixed lens group and a movable lens that is disposed between the first and second fixed lens groups and that is coupled to an actuator to move the movable lens relative to the image sensor and the first and second fixed lens groups in an auto focus zoom operation of the camera module.

2. The camera module of clam 1, wherein the first fixed lens group comprises at least two fixed lenses.

3. The camera module of claim 2, wherein the second fixed lens group comprises at least two fixed lenses.

4. The camera module of claim 3, wherein the movable lens is disposed in the middle between two pairs of fixed lenses.

5. An auto focus camera enabled embedded device, comprising:

an embedded device housing;

a processor within the housing;

a camera module within the embedded device housing, wherein the camera module includes

an image sensor; and

an optical train at least including a first fixed lens group nearest the image sensor and a second fixed lens group, and at least one movable lens disposed between the first and second fixed lens groups that is coupled to a MEMS actuator to move the movable lens relative to the image sensor and the first and second fixed lens groups in an auto focus operation of the camera module, and

processor readable code for programming the processor to perform an auto-focus operation.

6. An auto focus zoom camera module, comprising:

a camera module housing;

an optical train within the housing including a first fixed lens group, a second fixed lens group, and at least one movable lens disposed between the first and second fixed lens groups that is coupled to an actuator to move the movable lens relative to the first and second fixed lens groups;

an image sensor aligned with the optical train; and

processor-readable code for programming a processor to perform an auto focus zoom operation.

7. An auto focus zoom camera module as in claim 6, wherein the first and second fixed lens groups comprise two fixed lenses.

8. An auto focus zoom camera module, comprising:

a camera module housing;

an image sensor within the camera module housing;

an optical train within the camera module housing at least including a first fixed lens group nearest the image sensor, a second fixed lens group, and a movable lens group disposed between the first and second fixed lens groups that is coupled to a MEMS actuator configured to move the movable lens group relative to the image sensor and the first and second fixed lens groups in an auto focus zoom operation of the camera module.

9. The auto focus zoom camera module of claim 8, wherein the optical train comprises an even number of fixed lenses.

10. The auto focus zoom camera module of claim 8, wherein each of the first and second fixed lens groups of the optical train comprises two fixed lenses.

11. The auto focus zoom camera module of claim 8, wherein the first fixed lens group comprises a zoom lens that is disposed closest to the image sensor within the optical train.

12. The auto focus zoom camera module of claim 11, wherein the second fixed lens group is disposed along the optical path on the object side of the movable lens, wherein the first fixed lens group including said zoom lens is disposed on the sensor side of the movable lens.

13. The auto focus zoom camera module of claim 12, wherein each of the first and second fixed lens groups comprises at least two lenses.

14. The auto focus zoom camera module of claim 13, wherein lens diameters decrease from L1 to L3, and increase from L3 to L5, such that the movable auto focus lens (L3) has the smallest diameter of the five lenses (L1-L5 from object end to image end of the optical train).

15. The auto focus zoom camera module of claim 14, wherein lens L1 comprises a meniscus lens.

16. The auto focus zoom camera module of claim 15, wherein lens L2 also comprises a meniscus lens.

17. The auto focus zoom camera module of claim 16, wherein the movable auto focus lens L3 comprises a bi-convex lens.

18. The auto focus zoom camera module of claim 17, wherein the lens L4 comprises a complex bi-concave lens.

19. The auto focus zoom camera module of claim 18, wherein the lens L5 comprises a complex meniscus lens.

20. The auto focus zoom camera module of claim 19, further comprising an optical stop on the image side of the lens L1.

21. The auto focus zoom camera module of claim 20, further comprising stops on the scene sides of each of lenses L3, L4 and L5.

22. The auto focus zoom camera module of claim 21, wherein the stop on L3 is configured to move in tandem with the lens.

23. The auto focus zoom camera module of claim 8, wherein the MEMS actuator is configured to move a single lens L3 of the movable lens group relative to the image sensor and fixed lenses L1 and L2 of the first fixed lens group, and fixed lenses L4 and L5 of the second fixed lens group.

24. The auto focus zoom camera module of claim 23, wherein a range of movement of the lens L3 comprises approximately 50 μ

m to 350 μ

m.

25. The auto focus zoom camera module of claim 23, wherein a range of movement of the lens L3 comprises approximately 100 μ

m.

26. The auto focus zoom camera module of claim 23, wherein the optical train has been fabricated as a unitary component within the housing.

27. The auto focus zoom camera module of claim 26, wherein the housing comprises a screw thread permitting the focus of the camera to be set.

28. The auto focus zoom camera module of claim 26, wherein the optical train has been fabricated using passive and active alignment.

29. The auto focus zoom camera module of claim 28, wherein active alignment has been used between the MEMS actuator and the third fixed lens L4.

30. The auto focus zoom camera module of claim 23, wherein a spacing between L2 and L3 is within a range around approximately 100 μ

m to 300 μ

m, and the MEMS actuator moves the lens L3 along up to 90% of that spacing in an auto focus operation.

31. The auto focus zoom camera module of claim 23, wherein a spacing between L2 and L3 is within a range around approximately 190 μ

m, and the MEMS actuator moves the lens L3 along up to 90% of that spacing in an auto focus operation.

32. The auto focus zoom camera module of claim 23, wherein a spacing between L5 and the image sensor is within a range around approximately 500 μ

m to 1500 μ

m.

33. The auto focus zoom camera module of claim 23, wherein a spacing between L5 and the image sensor is within a range around approximately 900 μ

m.

34. The auto focus zoom camera module of claim 23, further comprising an infra red cut filter spaced from L5 within a range around 5 μ

m to 1000 μ

m.

35. The auto focus zoom camera module of claim 23, further comprising an infra red cut filter spaced from L5 within a range around approximately 250 μ

m.

36. A method of assembling an optical train for an auto focus zoom camera module that includes five lenses (respectively referred to as “

L1”

-“

L5”

from image to object), comprising;

coupling L1 to L2;

coupling L3 to a MEMS actuator;

coupling L4 to L5;

coupling the L1/L2 lens pair to the L3/MEMS assembly; and

coupling the L1/L2/L3/MEMS assembly to the L4/L5 lens pair.

37. An auto focus MEMS camera module, comprising:

an image sensor, an autofocus module including a MEMS actuator that is configured to move at least one movable lens along an optical axis of the camera module in an auto focus operation, and

a first fixed lens group nearest an object end of the optical path; and

a second fixed lens group nearest the sensor end of the optical path and spaced from the first fixed lens group at least 100 microns to permit the at least one movable lens to move through an auto focus range of the MEMS camera module, and

wherein the at least one movable lens is movable along the optical axis of the camera between the first and second fixed lens groups.

38. The auto focus MEMS camera module of claim 37, wherein the second fixed lens group is spaced from the first fixed lens group at least 190 microns to permit the at least one movable lens to move through an auto focus range of the MEMS camera module.

39. The auto focus MEMS camera module of claim 38, wherein the first and second fixed lens groups each comprise two or more fixed lenses that are fixed in position relative to the image sensor or camera housing or a rigid substrate or combinations thereof.