Lens assembly and method of manufacture

• US 20100039713A1
• Filed: 08/15/2008
• Published: 02/18/2010
• Est. Priority Date: 08/15/2008
• Status: Active Grant

• Current Assignee: Ether Precision, Inc.
• Original Assignee: Ether Precision, Inc.
• Inventors: Lusinchi, Jean-Pierre, Kui, Xiao-Yun
• Granted Patent: US 7,813,043 B2
• Time in Patent Office: Days
• US Class Current: 359/819
• 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: 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 lens assembly comprises a spacer plate having first and second surfaces, and an array of lens barrels that each comprise a lens opening extending inward from the first surface of the spacer plate and a sensor cavity extending inward from the second surface of the spacer plate. An alignment tool comprising an array of alignment holes or prongs is used to align the lens to the orifices of the lens openings.

Claims

1. A method of forming a lens module array for an image sensor array comprising a plurality of image sensors on a sensor substrate that are spaced apart by a spacing distance, the method comprising:

(a) providing an alignment tool comprising an array of alignment holes that are separated from one another by the spacing distance of the image sensors;

(b) placing at least one lens in each alignment hole of the alignment tool to form a lens filled alignment tool, each lens having an outer circumference;

(c) providing a spacer plate comprising;

(i) first and second surfaces, and

(ii) an array of lens barrels that each comprise a lens opening extending inward from the first surface of the spacer plate, and a sensor cavity extending inward from the second surface of the spacer plate to meet the lens opening;

(d) aligning the lens filled alignment tool onto the first surface of the spacer plate such that each lens is aligned to a lens opening of a lens barrel in the spacer plate;

(e) attaching outer circumferences of the lenses to the first surface of the spacer plate; and

(f) removing the alignment tool from the spacer plate to form a lens module array comprising a plurality of lens modules that each comprise a lens in a lens barrel of the spacer plate.

2. A method according to claim 1 wherein (a) comprises forming the alignment tool from metal.

3. A method according to claim 2 comprising forming the alignment tool in a thickness of from about 150 to about 1000 microns.

4. A method according to claim 1 wherein each lens comprises first and second surfaces, and wherein (b) comprises depositing an infrared reflective coating on the first surface of each lens.

5. A method according to claim 4 wherein (b) comprises depositing an antireflective coating on the second surface of each lens.

6. A method according to claim 1 wherein (c) comprises forming the lens opening to allow self-alignment of the lens when it is inserted into the lens opening.

7. A method according to claim 1 wherein (c) comprises forming the lens barrels such that the lens openings have a conical flange with an angle that is selected so that a light ray at a maximum angle of light passing through the lens does not touch the sidewall of the lens opening.

8. A method according to claim 1 wherein (c) comprises forming the lens barrels such that the lens openings comprise a conical flange that is sloped at an angle relative to a central vertical axis of the lens of from about 0 degrees to about 30 degrees.

9. A method according to claim 1 wherein (c) comprises forming the spacer plate from glass.

10. A method according to claim 9 further comprising forming each lens from glass.

11. A method according to claim 1 wherein the outer circumference of each lens extends beyond the first diameter of the lens opening to provide an attachment region, and wherein (e) comprises attaching the lenses to the first surface of the spacer plate at the attachment regions.

12. A method according to claim 10 wherein (e) comprises attaching the lenses to the first surface of the spacer plate with an adhesive.

13. A method according to claim 1 further comprising aligning the lens module array to an image sensor array comprising a plurality of image sensors that each fit within a cavity of a lens barrel of the spacer plate to be positioned under a lens.

14. A method according to claim 1 further comprising providing a saddle comprising an array of saddle openings that are each sized to fit around a lens, and aligning the saddle openings over the lenses of the lens module array.

15. A method according to claim 1 further comprising providing a lens cover plate to protect each lens in each saddle opening of the saddle.

16. A method according to claim 1 further comprising coating the lens opening of the spacer in contact with the lens with an opaque coating.

17. A lens module array comprising:

(a) a spacer plate comprising;

(i) first and second surfaces, and

(ii) an array of lens barrels that each comprise a lens opening extending inward from the first surface of the spacer plate, and a sensor cavity extending inward from the second surface of the spacer plate to meet the lens opening; and

(b) at least one lens positioned over each lens opening of a lens barrel, the outer circumference of the lens being attached to the spacer plate.

18. A lens assembly according to claim 17 wherein the outer circumference of each lens extends beyond a diameter of the lens opening at the first surface of the spacer plate to provide an attachment region, and wherein the lenses are attached to the spacer plate at the attachment regions.

19. A lens assembly according to claim 18 wherein the lenses are attached to the spacer plate with an adhesive.

20. A lens assembly according to claim 17 wherein each lens comprises first and second surfaces, and wherein an infrared reflective coating is on the first surface of each lens.

21. A lens assembly according to claim 20 wherein an antireflective coating is on the second surface of each lens.

22. A lens assembly according to claim 17 wherein the lens opening comprises a sidewall having a profile that matches the contour of a lens.

23. A lens assembly according to claim 17 wherein the lens openings have a conical flange with an angle that is selected so that a light ray at a maximum angle of light passing through the lens does not touch the sidewall of the lens opening.

24. A lens assembly according to claim 17 wherein the lens openings comprise a conical flange that is sloped at an angle relative to the a central vertical axis of the lens of from about 0 degrees to about 30 degrees.

25. A lens assembly according to claim 17 wherein the spacer plate comprises glass.

26. A lens assembly according to claim 17 wherein the outer circumference of each lens extends beyond the first diameter of the lens opening to provide an attachment region for attaching the lenses to the first surface of the spacer plate.

27. A lens assembly according to claim 17 wherein the lenses are attached to the first surface of the spacer plate with an adhesive.

28. A method of forming a lens module array for an image sensor array comprising a plurality of image sensors on a sensor substrate that are spaced apart by a spacing distance, the method comprising:

(a) forming a spacer plate comprising first and second surfaces, and an array of lens barrels that each comprise (i) a lens opening that extends inward from a first surface of the spacer plate to end in an orifice having a circumferential edge, the lens openings separated from one another by a lens spacing distance that corresponds to the sensor spacing distance, and (ii) a sensor cavity that extends inward from a second surface of the spacer plate to meet the lens opening;

(b) applying an adhesive to the circumferential edge of the orifice of the lens opening;

(c) placing a lens in each orifice of each lens opening;

(d) providing an alignment tool comprising an array of alignment prongs that are separated from one another by the lens spacing distance;

(e) inserting the alignment prongs of the alignment tool into the lens openings of the lens barrels, wherein each alignment prong aligns a lens to an orifice of a lens opening of a lens barrel; and

(f) removing the alignment tool from the spacer plate to form a lens module array comprising a plurality of lens modules that each comprises a lens adhered to an orifice of a lens opening of a lens barrel of the spacer plate.

29. A method according to claim 28 wherein (b) comprises:

(i) placing a mask on the first surface of the spacer plate, the mask having holes that are arranged in a periodic relationship that corresponds to the spacing of the lens openings, and

(ii) spraying an adhesive through the holes of the mask to form an adhesive coating on the circumferential edge of the orifice.

30. A method according to claim 28 comprising forming lens openings comprising a circumferential edge that is a sloped flange.

31. A method according to claim 28 wherein the sloped flange comprises an angle of inclination of from about 2 to about 30 degrees.

32. A method according to claim 28 wherein (d) comprises forming an alignment tool comprising metal.

33. A method according to claim 32 comprising forming an alignment tool having from about 100 to about 5000 prongs.

34. A method according to claim 33 wherein the prongs comprise a length of from about 0.5 to about 5 mm.

35. A method according to claim 28 comprising depositing an infrared reflective coating on a first surface of each lens.

36. A method according to claim 35 comprising depositing an antireflective coating on a second surface of each lens.

37. A method according to claim 28 wherein (a) comprises forming the spacer plate and lenses from glass.

38. A lens module array comprising:

(a) a spacer plate comprising first and second surfaces, and an array of lens barrels that each comprise (i) a lens opening that extends inward from a first surface of the spacer plate to end in an orifice having a circumferential edge, the lens openings separated from one another by a lens spacing distance, and (ii) a sensor cavity that extends inward from a second surface of the spacer plate to meet the lens opening;

(b) at least one lens in each lens opening of a lens barrel, each lens having an outer circumference that is adhered to a circumferential edge of an orifice of a lens opening of a lens barrel of the spacer plate with an adhesive.

39. A lens assembly according to claim 38 wherein each lens opening comprises a circumferential edge that is a sloped flange.

40. A lens assembly according to claim 39 wherein the sloped flange comprises an angle of inclination of from about 2 to about 30 degrees.

41. A lens assembly according to claim 38 comprising an infrared reflective coating on a first surface of each lens.

42. A lens assembly according to claim 41 comprising an antireflective coating on a second surface of each lens.

43. A lens assembly according to claim 38 wherein the spacer plate and lenses are made from glass.

44. An image capturing unit comprising:

(a) a spacer plate comprising;

(i) first and second surfaces, and

(ii) an array of lens barrels that each comprise a lens opening extending inward from the first surface of the spacer plate, and a sensor cavity extending inward from the second surface of the spacer plate to meet the lens opening;

(b) a lens positioned in each lens opening of a lens barrel, each lens having an outer circumference that is attached to the spacer plate; and

(c) a sensor positioned within each sensor cavity of a lens barrel to be under a lens.

45. An image capturing unit according to claim 44 wherein the outer circumference of each lens extends beyond a diameter of the lens opening at the first surface of the spacer plate to provide an attachment region, and wherein the lenses are attached to the spacer plate at the attachment regions.

46. An image capturing unit according to claim 45 wherein the lenses are attached to the spacer plate with an adhesive.

47. An image capturing unit according to claim 45 wherein each lens opening ends in an orifice having a circumferential edge, and each lens comprises an outer circumference that is adhered to a circumferential edge of the orifice of the lens opening of a lens barrel with an adhesive.

48. An image capturing unit according to claim 47 wherein the circumferential edge is a sloped flange.

49. An image capturing unit according to claim 48 wherein the sloped flange comprises an angle of inclination of from about 2 to about 30 degrees.

50. An image capturing unit according to claim 44 comprising an infrared reflective coating on a first surface of each lens.

51. An image capturing unit according to claim 50 comprising an antireflective coating on a second surface of each lens.

52. An image capturing unit according to claim 44 wherein the spacer plate and lenses are made from glass.

53. An image capturing unit according to claim 44 further comprising a saddle having an array of saddle openings that are each sized to fit around a lens.

54. An image capturing unit according to claim 44 comprising a lens cover plate over the saddle.