OPTICAL SYSTEM, BARREL, AND OPTICAL INSTRUMENT USING SAME

• US 20120275027A1
• Filed: 04/24/2012
• Published: 11/01/2012
• Est. Priority Date: 04/26/2011
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: OKUNO, Takeharu
• Granted Patent: US 9,250,362 B2
• Time in Patent Office: Days
• US Class Current: 359/601
• CPC Class Codes: G02B 1/115 Multilayers
• CPC Class Codes: G02B 1/118 having sub-optical wavelength surface structures designed to provide an enhanced transmittance, e.g. moth-eye structures
• CPC Class Codes: G02B 2207/107 Porous materials, e.g. for reducing the refractive index
• CPC Class Codes: G02B 7/025 using glue

Abstract

Provided is an optical system having at least two or more lenses, wherein at least one of the lenses comprises an anti-reflection film formed by a wetting method on a part of or the entirety of the light beam effective surface thereof, and wherein at least one of the lenses other than the lens comprising the anti-reflection film is fixed to the space between the lens and a barrel for holding the lens via an energy-curable resin to be filled therein.

Claims

1. An optical system having at least two or more lenses,

wherein at least one of the lenses comprises an anti-reflection film formed by a wetting method on a part of or the entirety of a light beam effective surface thereof, and

wherein at least one of the lenses other than the lens comprising the anti-reflection film is fixed to a space between the lens and a barrel for holding the lens via an energy-curable resin to be filled therein.

2. The optical system according to claim 1, wherein the energy-curable resin is an epoxy-type UV-curable resin.

3. The optical system according to claim 2, wherein the epoxy-type UV-curable resin contains 10% by weight or more of an epoxy resin.

4. The optical system according to claim 2, wherein the epoxy-type UV-curable resin contains 0.5% by weight or more of silica.

5. The optical system according to claim 2, wherein the viscosity of an uncured epoxy-type UV-curable resin is in a range from 1 Pa·

s to 50 Pa·

s.

6. The optical system according to claim 1, wherein the energy-curable resin is brought into abutment between an epoxy-type UV-curable resin and an acrylic UV-curable resin or a silicone UV-curable resin.

7. The optical system according to claim 6, wherein the epoxy-type UV-curable resin is disposed on the side of the lens comprising the anti-reflection film.

8. The optical system according to claim 6, wherein the epoxy-type UV-curable resin contains 10% by weight or more of an epoxy resin.

9. The optical system according to claim 6, wherein the epoxy-type UV-curable resin contains 0.5% by weight or more of silica.

10. The optical system according to claim 6, wherein the viscosity of the uncured epoxy-type UV-curable resin is in a range from 1 Pa·

s to 50 Pa·

s.

11. The optical system according to claim 1, wherein the anti-reflection film has a fine concave-convex feature having an average pitch of 400 nm or less.

12. The optical system according to claim 11, wherein a concave-convex structure constituting the fine concave-convex feature contains aluminum oxide.

13. The optical system according to claim 1, wherein the anti-reflection film contains fluoride microparticles or hollow silica microparticles.

14. The optical system according to claim 1, wherein the lens held via the energy-curable resin is a lens which is joined with at least one concave lens or which is brought into abutment with at least one concave lens, and

wherein, when the outer diameter of the concave lens is “

D” and

the central thickness thereof is “

t”

, the value of t/D is 0.1 or less.

15. Optical instrument having an optical system,

wherein the optical system is the optical system according to claim 1.

16. A barrel that holds a first lens and a second lens,

wherein the second lens comprises an anti-reflection film having a fine concave-convex feature on a part of or the entirety of the light beam effective surface thereof,

wherein the first lens is fixed to the barrel via an energy-curable resin which is an epoxy-type UV-curable resin or a UV-curable resin containing the epoxy-type UV-curable resin, and

wherein the anti-reflection film having the fine concave-convex feature and the energy-curable resin are disposed inside a communicating space.

17. The barrel according to claim 16,

wherein the energy-curable resin does not contain acrylate monomers and methacrylate monomers.

18. Optical instrument having a barrel,

wherein the barrel is the barrel according to claim 16.