DIFFRACTIVE OPTICAL ELEMENT AND USE OF AN OPTICAL ADHESIVE FOR PRODUCING THE SAME

• US 20110026118A1
• Filed: 09/19/2008
• Published: 02/03/2011
• Est. Priority Date: 10/31/2007
• Status: Active Grant

• Current Assignee: Carl Zeiss AG (Carl-Zeiss-Stiftung)
• Original Assignee: Carl Zeiss AG (Carl-Zeiss-Stiftung)
• Inventors: Weippert, Hans-Joachim, Seesselberg, Markus
• Granted Patent: US 8,503,080 B2
• Time in Patent Office: Days
• US Class Current: 359/558
• CPC Class Codes: C08K 5/0008 Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
• CPC Class Codes: C09J 163/00 Adhesives based on epoxy resins; Adhesives based on derivatives of epoxy resins
• CPC Class Codes: G02B 5/1852 using mechanical means, e.g. ruling with diamond tool, moulding

Abstract

A diffractive optical element is provided, which comprises a first layer (12) consisting of a material having a refractive index n₁(λ), a second layer (14), adjacent to the first layer (12), consisting of a material having a refractive index n₂(λ) and a diffraction structure (18) formed at the interface (16) between the first layer (12) and the second layer (14). The material of at least one of the two layers (12, 14) is obtained by curing an optical adhesive. The use of an optical adhesive for the production of a diffractive optical element according to claim 1 is furthermore provided.

Claims

1. An optical element, comprising:

a) a first layer comprising a first material having a refractive index n₁(λ

);

b) a second layer comprising a second material having a refractive index n₂(λ

), the second layer being adjacent the first layer; and

c) a diffraction structure at an interface between the first layer and the second layer,

wherein the first material and/or the second material is obtained by curing an optical adhesive, and the optical element is a diffractive optical element.

2. The optical element according to claim 1, wherein the optical adhesive is based on an epoxy adhesive or a thiolene system.

3. The optical element according to claim 2, wherein the optical adhesive comprises a compound selected from the group consisting of:

bis-[4-(2,3-epoxypropylthio)-phenyl]sulfide;

N,N-diglycidyl-4-glycidyl-oxyaniline;

bis-(3,4-epoxycyclohexyl)adipate;

polyethylene glycol;

bis-(4-vinylthiophenyl)sulfide; and

pentaerythritol tetra-(3-mercaptopropionate).

4. The optical element according to claim 3, wherein the optical adhesive comprises bis-[4-(2,3-epoxypropylthio)-phenyl]sulfide in an amount of from about 20.00% to about 85.00%, expressed in terms of its total weight.

5. The optical element according to claim 3, wherein the optical adhesive comprises N,N-diglycidyl-4-glycidyl-oxyaniline in an amount of from about 24.00% to about 33.00%, expressed in terms of its total weight.

6. The optical element according to claim 1, wherein the optical adhesive comprises a curer.

7. The optical element according to claim 6, wherein the optical adhesive comprises as a curer a compound selected from the group consisting of:

trimethylhexamethylene-1,6-diamine;

diamino-m-xylene;

naphthalene-methylamine; and

isophorone diamine.

8. The optical element according to claim 7, wherein the optical adhesive comprises as a curer in the amounts specified, expressed in terms of its total weight a compound selected from the group consisting of:

trimethylhexamethylene-1,6-diamine in an amount of from about 16.00% to about 18.50%;

diamino-m-xylene in an amount of from about 14.00% to about 15.00;

naphthalene-methylamine in an amount of from about 28.00% to about 29.00%; and

isophorone diamine in an amount of from about 13.50% to about 14.50%.

9. The optical element according to claim 1, wherein the optical adhesive can be cured by electromagnetic radiation.

10. The optical element according to claim 9, wherein the optical adhesive comprises in the amounts specified, expressed in terms of its total weight a compound selected from the group consisting of:

bis-(3,4-epoxycyclohexyl) adipate in an amount of from about 55.00% to about 65.00%;

bis-(4-vinylthiophenyl)sulfide in an amount of from about 50.00% to about 80.00%; and

pentaerythritol tetra-(3-mercaptopropionate) in an amount of from about 17.00% to about 45.00%.

11. The optical element according to claim 9, wherein the optical adhesive comprises polyethylene glycol in an amount of from about 15.00% to about 20.00%, expressed in terms of its total weight.

12. The optical element according to claim 9, wherein the optical adhesive comprises a photoinitiator.

13. The optical element according to claim 12, wherein the optical adhesive comprises as a photoinitiator a compound selected from the group consisting of:

triarylsulfonium hexafluoroantimonate;

triarylsulfonium hexafluorophosphate;

bis(2,6-dimethoxybenzoyl)-2,4,4 trimethylpentylphosphine oxide;

2-hydroxy-2-methyl-1-phenyl-propan-1-one; and

1-[4-(1-methylethyl)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one.

14. The optical element according to claim 13, wherein the optical adhesive comprises as a photoinitiator in the amounts specified, expressed in terms of its total weight a compound selected from the group consisting of:

triarylsulfonium hexafluorophosphate in an amount of from about 2.00% to about 2.80%; and

a mixture comprising 25% bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide and 75% 2-hydroxy-2-methyl-1-phenyl-propan-1-one in an amount of from about 2.50% to about 4.50%.

15. The optical element according to claim 1, wherein the optical adhesive comprises an adhesion promoter.

16. The optical element according to claim 15, wherein the optical adhesive comprises as an adhesion promoter at least one compound selected from the group consisting of:

3-glycidyloxypropyltrimethoxysilane;

3-aminopropyltrimethoxysilane;

3-mercaptopropyl-trimethoxysilane;

vinyltrimethoxysilane; and

3-methacryloxypropyltrimethoxysilane or a similar triethoxysilane.

17. The optical element according to claim 16, wherein the optical adhesive comprises as an adhesion promoter in the amounts specified, expressed in terms of its total weight a compound selected from the group consisting of:

3-glycidyloxypropyltrimethoxysilane in an amount of from about 0.70% to about 2.40%; and

3-mercaptopropyl-trimethoxysilane in an amount of from about 0.70% to about 0.80%.

18. The optical element according to claim 1, wherein the optical adhesive comprises a plasticiser.

19. The optical element according to claim 18, wherein the optical adhesive comprises as a plasticiser a compound selected from the group consisting of:

methyl salicylate;

benzyl salicylate;

hydroxyethyl salicylate;

benzyl benzoate;

1-phenylnaphthalene;

diisopropyl-naphthalene;

isopropyl biphenyl; and

2-trifluormethylbenzyl alcohol.

20. The optical element according to claim 19, wherein the optical adhesive comprises methyl salicylate in an amount of from about 17.00% to 25.00%, expressed in terms of its total weight.

21. The optical element according to claim 1, wherein the second material is obtained by curing the optical adhesive, and n₁(λ

)>

n₂(λ

).

22. The optical element according to claim 21, wherein the first material is an optical glass material.

23. The optical element according to claim 22, wherein the first material is a press-mouldable optical glass material.

24. The optical element according to claim 21, wherein the first material is an optical plastic material.

43. The optical element according to claim 1, wherein the cured optical adhesive is at least 5 μ

m at its thinnest position.

44. The optical element according to claim 1, wherein the outer surface of the second layer, which faces away from the first layer, is configured as a refractive lens surface.

45. The optical element according to claim 44, wherein the refractive lens surface is convex or concave.

46. The optical element according to claim 1, further comprising a third layer comprising a third material having a refractive index n₃(λ

) lies adjacent to the outer surface of the second layer, which faces away from the first layer.

25-42. -42. (canceled)

47-48. -48. (canceled)

49. A method, comprising:

fabricating a diffractive optical element comprising curing an optical adhesive to produce a cured optical adhesive material, wherein the diffractive optical element comprises;

a first layer comprising a first material having a refractive index n₁(λ

);

a second layer comprising a second material having a refractive index n₂(λ

), the second layer being adjacent the first layer; and

a diffraction structure formed at an interface between the first layer and the second layer,

wherein the first material and/or the second material is the cured optical adhesive material.

50. (canceled)