Positioning wafer lenses on electronic imagers

• US 8,063,975 B2
• Filed: 10/29/2008
• Issued: 11/22/2011
• Est. Priority Date: 10/29/2008
• Status: Active Grant

• Current Assignee: Jabil Circuit Incorporated (Jabil Inc.)
• Original Assignee: Jabil Circuit Incorporated (Jabil Inc.)
• Inventors: Kujanpaa, Karo, Butterfield, Andrew, Fabre, Sebastien
• Primary Examiner(s): Ye; Lin
• Assistant Examiner(s): Hsu; Amy
• Application Number:
  US12/260,915
• Publication Number:
  US 20100103308A1
• Time in Patent Office: 1,119 Days
• Field of Search: 348/340
• US Class Current: 348/340
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: H01L 27/14685 Process for coatings or optical elements
• CPC Class Codes: H04N 17/002 for television cameras
• 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

A low cost manufacturing method (300) and assembly (100) for positioning a lens (106) relative to an electronic imager (102). A viscous adhesive (104) is applied to the lens (106) or the electronic imager (102) outside of the optical path. The lens (106) is disposed on the electronic imager (102) exclusively with the adhesive (104) disposed between them.

Claims

1. A method for positioning a lens relative to an imager without use of a lens holder, comprising:

disposing an accumulation of an adhesive having a viscous form, outside an optical imaging region of said lens and said imager, so that said adhesive exclusively bridges a distance between the lens and the imager;

positioning said lens adjacent to said imager a spaced distance apart, separated by at least a portion of said adhesive;

aligning said lens at a precise distance from said imager based on a focal length of said lens, by selectively displacing a portion of said adhesive.

2. The method according to claim 1, further comprising curing said adhesive while said lens is at said precise distance from said imager.

3. The method according to claim 2, further comprising selecting said adhesive to include an epoxy resin.

4. The method according to claim 1, further comprising curing said adhesive following said aligning step by exposing said adhesive to at least one initiator selected from the group consisting of heat and light.

5. The method according to claim 4, further comprising selecting said initiator to include ultra-violet light.

6. The method according to claim 4, further comprising selecting said adhesive to have a snap cure time which is less than about 1 minute.

7. The method according to claim 1, further comprising selecting a thickness of said adhesive applied to said lens or said imager to be greater than a focal length of said lens.

8. The method according to claim 1, wherein said aligning step further comprises adjusting an orientation of said lens relative to said imager.

9. The method according to claim 1, wherein said aligning step further comprises adjusting a lateral position of said lens relative to said imager by moving said lens in at least one direction transverse to a direction defined by said focal distance.

10. The method according to claim 1, further comprising selecting said adhesive to have a viscosity of about 10000±

500 centipoise.

11. The method according to claim 1, further comprising automatically performing said alignment step by:

applying electrical power to said imager; and

evaluating an image produced by said imager with said lens in a selected position.

12. The method according to claim 11, further comprising selectively varying a position of said lens relative to said imager and repeating said evaluating step until an optimal image is determined to have been achieved with said imager and said lens.

13. The method according to claim 1, wherein said disposing step further comprises disposing said adhesive on at least one structure selected from the group consisting of a peripheral portion of said imager, and a surface at least partially surrounding said imager comprising a substrate on which said imager is disposed.

14. An imaging system, comprising:

an electronic imager having an imaging surface comprising a plurality of pixels;

a lens configured for focusing an image on said imaging surface, said lens having a lens position a predetermined distance from said imaging surface axially aligned with said imager so that a focal plane of said lens is generally parallel to said imaging surface; and

a positioning structure securing said lens in said lens position relative to said imager, said positioning structure comprising an adhesive that fixes said lens in position relative to said imager without use of any intervening mechanical structure for positioning the lens.

15. The imaging system according to claim 14, wherein said adhesive is an epoxy resin.

16. The imaging system according to claim 14, wherein said adhesive comprises a catalyst which accelerates curing of said adhesive, and said catalyst is responsive to an initiator.

17. The imaging system according to claim 16, wherein said initiator is selected from the group comprising heat and light.

18. The imaging system according to claim 17, wherein said initiator is ultraviolet light.

19. The imaging system according to claim 16, wherein said adhesive has a snap cure time which is less than about 1 minute.

20. The imaging system according to claim 14, wherein a thickness of said adhesive between said lens and said electronic imager is equal to a focal length of said lens.

21. The imaging system according to claim 14, wherein said adhesive has a cured state and an uncured state, and has a viscosity of about 10000±

500 centipoise in said uncured state.

22. A method for positioning a lens relative to an imaging surface defined by an imager, the lens having no lens barrel, comprising:

applying an adhesive in an uncured state to a portion of the lens or the imager outside an optical imaging region of said lens and said imager, wherein the adhesive has a viscosity selected such that the adhesive provides for an adjustable support and positioning mechanism for the lens while in the uncured state;

positioning said lens relative to said imager at a spaced distance apart, separated by said uncured adhesive;

evaluating an image produced by said imager and said lens combination, while said adhesive is in an uncured state;

selectively adjusting a position of said lens relative to said imager responsive to said evaluating step by repositioning said lens to displace a portion of said uncured adhesive; and

curing the adhesive to fix a position of the lens relative to said imager.

23. An imaging system having a lens and imager fixed relative to each other without use of a lens holder, comprising:

an electronic imager having an imaging surface;

a lens that is configured to focus an image on the imaging surface;

an adhesive material disposed about the imaging surface of the electronic imager that secures the lens in axial alignment with the imaging surface; and

wherein the adhesive operates as a positioning structure for maintaining orientation of the lens with respect to the imaging surface so that a focal plane of said lens is generally parallel to said imaging surface.

24. The imaging system as in claim 23, wherein the adhesive includes a catalyst that is responsive to an initiator for accelerating curing of the adhesive.

25. The imaging system according to claim 23, wherein the adhesive has a viscosity of approximately 10000±

500 centipoise when in an uncured state.

26. An imaging system, comprising:

an electronic imager having an imaging surface;

a lens for focusing an image on the imaging surface; and

means for securing and orienting said lens with respect to said imager, said means comprising primarily of an adhesive selectively displaced about the imaging surface through active alignment of the lens.

27. The imaging system as in claim 26, wherein the adhesive includes a catalyst that is responsive to an initiator for accelerating curing of the adhesive.

28. The imaging system according to claim 27, wherein the adhesive means has a viscosity of approximately 10000±

500 centipoise when in an uncured state.

29. A method for manufacturing a camera module, comprising the steps of:

disposing an accumulation of uncured adhesive on an imager and on a lens, such that the adhesive is outside an optical imaging region of said lens and said imager, the adhesive having a viscous form that maintains a spaced apart distance between the lens and imager; and

actively aligning the lens by selectively displacing a portion of said adhesive to adjust position and orientation of the lens relative to said imager thereby focusing the lens with respect to the imager; and

after the step of actively aligning, curing the adhesive to fix the position and orientation of the lens relative to the imager.

30. The method according to claim 29, further comprising automatically performing said alignment step by:

applying electrical power to said imager;

evaluating an image produced by said imager with said lens in a selected position; and

adjusting position and orientation of the lens relative to the imager based on evaluating the image.

31. An imaging system, comprising:

a lens stack having no lens barrel;

an electronic imager having an imaging surface, and a region outside the imaging surface;

an adhesive material disposed on the electronic imager on the region outside the imaging surface; and

wherein the lens stack is secured directly to the electronic imager by the adhesive material, without an intervening mechanical structure, and the lens stack is positioned by the adhesive relative to the imager such that a focal plane of said lens stack is generally parallel to said imaging surface.

32. The imaging system of claim 31, wherein the adhesive has a cured state derived from an uncured state, and when in the uncured state, the adhesive has a characteristic viscosity of approximately 10000±

500 centipoise.

33. The imaging system of claim 31, wherein the adhesive has a thickness that varies between the lens stack and image to compensate for tolerances in the lens stack and the imager, thereby maintain the lens stack in axial alignment with respect to the imager.