Cemented lens group

• US 6,816,322 B2
• Filed: 10/31/2002
• Issued: 11/09/2004
• Est. Priority Date: 11/01/2001
• Status: Expired due to Fees

• Current Assignee: Pentax Corporation (Hoya Corporation)
• Original Assignee: Pentax Corporation (Hoya Corporation)
• Inventors: Abe, Tetsuya, Komori, Kazunori
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): CHOI, WILLIAM C
• Application Number:
  US10/284,362
• Publication Number:
  US 20030086184A1
• Time in Patent Office: 740 Days
• Field of Search: 359/642, 359/793-796, 351/163
• US Class Current: 359/796
• CPC Class Codes: G02B 3/00 Simple or compound lenses
• CPC Class Codes: G02B 7/008 with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation

Abstract

A cemented lens group including two lens elements, which are cemented to each other by an adhesive; wherein an adhesive layer formed by the adhesive between the two lens elements has elasticity, and the following condition(1) is satisfied:

|Δα·D/d|<0.03  (1).

Δα designates a difference in linear expansion coefficient between the two lens elements, D designates the diameter of each of the lens elements, and d designates a thickness of the adhesive layer.

Claims

1. A cemented lens group comprising two lens elements, cementing surfaces of said two lens elements being cemented to each other by an adhesive;

wherein an adhesive layer formed by said adhesive between said two lens elements has elasticity; and

wherein the following condition(1) is satisfied;

2. The cemented lens group according to claim 1, wherein the following condition (1′

) is satisfied;

 

|Δ

α

·

D/d|<

0.01 

 

(1′

).

3. The cemented lens group according to claim 1, wherein said two lens elements comprise a positive lens element and a negative lens element, respectively, and wherein the following condition (3) is satisfied:

4. The cemented lens group according to claim 3, wherein the following condition (4) is satisfied;

5. The cemented lens group according to claim 1, wherein the following condition (5) is satisfied:

6. The cemented lens group according to claim 1, wherein the following condition (6) is satisfied:

7. The cemented lens group according to claim 1, wherein the following condition (7) is satisfied:

8. The cemented lens group according to claim 1, wherein the following condition (8) is satisfied:

9. The cemented lens group according to claim 1, wherein said adhesive comprises a silicon resin made of an organic silicon compound.

10. The cemented lens group according to claim 9, wherein said adhesive comprises an addition-reaction silicon resin.

11. The cemented lens group according to claim 1, wherein said adhesive comprises a silicon resin having an elongation of at least 100 percent.

12. The cemented lens group according to claim 1, wherein said cementing surfaces comprise a convex surface and a concave surface;

wherein a radius of curvature of said concave surface is greater than a radius of curvature of said convex surface.

13. A cemented lens group including two lens elements, cementing surfaces of said two lens elements being cemented to each other by an adhesive;

wherein a radius of curvature of each said cementing surfaces is determined so that a space between said cementing surfaces in the vicinity of periphery of said cementing surfaces becomes greater than a space between said cementing surfaces at an optical axis of said cemented lens group;

wherein an adhesive layer formed by said adhesive between said two lens elements has elasticity; and

wherein the following condition (9) is satisfied;

14. The cemented lens group according to claim 13, wherein the following condition (9′

) is satisfied;

15. The cemented lens group according to claim 13, wherein said cementing surfaces are cemented to each other after said two lens elements are precisely aligned.

16. The cemented lens group according to claim 13, wherein said two lens elements comprise a positive lens element and a negative lens element, respectively, and wherein the following condition (3) is satisfied:

17. The cemented lens group according to claim 16, wherein the following condition (4) is satisfied:

18. The cemented lens group according to claim 13, wherein the following condition (11) is satisfied:

19. The cemented lens group according to claim 13, wherein the following condition (12) is satisfied:

20. The cemented lens group according to claim 13, wherein the following condition (7) is satisfied:

21. The cemented lens group according to claim 13, wherein the following condition (8) is satisfied:

22. The cemented lens group according to claim 13, wherein said adhesive comprises a silicon resin made of an organic silicon compound.

23. The cemented lens group according to claim 22, wherein said adhesive comprises an addition-reaction silicon resin.

24. The cemented lens group according to claim 13, wherein said adhesive comprises a silicon resin having an elongation of at least 100 percent.

25. The cemented lens group according to claim 13, wherein said radius of curvature of each said cementing surfaces is determined so that a space between said cementing surfaces increases in radial directions away from an optical axis of said cemented lens group.

26. The cemented lens group according to claim 13, wherein said cementing surfaces comprise a convex surface and a concave surface;

wherein a radius of curvature of said concave surface is greater than a radius of curvature of said convex surface.