Optical device and method for manufacturing optical device

1. An optical device comprising:

a polarizer having a polarizing layer that consists of triacetylcellulose-free and uniaxially extended polyvinyl alcohol, the polarizing layer absorbing polarized light in a direction parallel to the uniaxially extending direction and transmitting polarized light in a direction perpendicular to the uniaxially extending direction;

a first light-transmissive substrate bonded on one surface of the polarizing layer of the polarizer by a first bonding material; and

a second light-transmissive substrate bonded on the other surface of the polarizing layer of the polarizer by a second bonding material;

the first light-transmissive substrate and the second light-transmissive substrate being made of an inorganic material, and

the optical device not including an organic material except the polarizing layer, the first bonding material and the second bonding material.

2. The optical device according to claim 1 ,

at least one of the first light-transmissive substrate and the second light-transmissive substrate being made of sapphire or quartz.

3. The optical device according to claim 1 ,

at least one of the first light-transmissive substrate and the second light-transmissive substrate being made of quartz glass, hard glass or other light-transmissive glasses.

4. The optical device according to claim 1 ,

at least one of the first light-transmissive substrate and the second light-transmissive substrate being made of crystalline glass or sintered body of cubic crystal.

5. The optical device according to claim 1 ,

at least one of the first light-transmissive substrate and the second light-transmissive substrate being made of a material having an optic axis, and

the first light-transmissive substrate and the second light-transmissive substrate being arranged with respect to the polarizing layer so that the optic axis of the light-transmissive substrate made of the material having the optic axis is substantially parallel or substantially perpendicular to the polarization axis of the polarizing layer.

6. The optical device according to claim 1 ,

the first light-transmissive substrate and the second light-transmissive substrate being made of the same material.

7. A method for manufacturing an optical device including a polarizer having a polarizing layer and a first light-transmissive substrate and a second light-transmissive substrate that are made of an inorganic material having an optic axis, the method comprising:

applying a pressure-sensitive-adhesive to one surface of the polarizing layer of the polarizer, the polarizing layer consisting of triacetylcellulose-free and uniaxially extended polyvinyl alcohol, the polarizing layer absorbing polarized light in a direction parallel to the uniaxially extending direction and transmitting polarized light in a direction perpendicular to the uniaxially extending direction;

bonding the one surface of the polarizing layer and the first light-transmissive substrate with the pressure-sensitive-adhesive;

applying an adhesive to the other surface of the polarizing layer of the polarizer; and

bonding the other surface of the polarizing layer and the second light-transmissive substrate with the adhesive, in this order,

the optical device not including an organic material except the polarizing layer, the pressure-sensitive-adhesive and the adhesive.

8. The method for manufacturing an optical device according to claim 7 ,

between the bonding the polarizing layer and the first light-transmissive substrate and the application of the adhesive, performing heat treatment for the polarizing layer bonded on the first light-transmissive substrate with the pressure-sensitive-adhesive.

9. The method for manufacturing an optical device according to claim 7 ,

in the bonding the polarizing layer and the first light-transmissive substrate, the polarizing layer and the first light-transmissive substrate are bonded so that the optic axis of the first light-transmissive substrate and the polarization axis of the polarizing layer become substantially parallel or substantially perpendicular to each other, and

in the bonding the polarizing layer and the second light-transmissive substrate, the polarizing layer and the second light-transmissive substrate are bonded so that the optic axis of the second light-transmissive substrate and the polarization axis of the polarizing layer become substantially parallel or substantially perpendicular to each other.

10. The method for manufacturing an optical device according to claim 7 ,

an ultraviolet hardening adhesive being used as the adhesive, and

in the bonding the polarizing layer and the second light-transmissive substrate, casting ultraviolet rays to the adhesive to harden the adhesive.

11. The optical device according to claim 1 ,

the materials of the first and second light-transmissive substrates having a smaller coefficient of thermal expansion than that of the polarizer.

12. The optical device according to claim 1 ,

at least one of the first and second light-transmissive substrates being made of a material having no optic axis.

13. The method for manufacturing an optical device according to claim 7 ,

the materials of the first and second light-transmissive substrates having a smaller coefficient of thermal expansion than that of the polarizer.

14. The method for manufacturing an optical device according to claim 7 ,

at least one of the first and second light-transmissive substrates being made of a material having no optic axis.