Optical transparent member and optical system using the same
It is an object to provide an optical transparent member capable of maintaining a high-performance antireflection effect for a base over a long period of time, and an optical system using the same, specifically an optical transparent member including on a base a layer containing SiO 2 as a main component, a layer containing Al 2 O 3 as a main component, and a plate crystal layer formed from plate crystals containing Al 2 O 3 as a main component, wherein the surface of the plate crystal layer has a shape of irregularities, and an optical system using the same.
1. A method for producing an optical member, comprising:
forming a layer having a refractive index n s directly on a surface of a base having a refractive index n b wherein the refractive indexes satisfy a relation of n b ≧n s ,
thereafter, forming an aluminum layer directly on the layer having a refractive index n s , and
subjecting the aluminum layer to treatment with hot water, to thereby form a layer containing aluminum oxide as a main component, having a refractive index n a , and having an irregularity structure,
wherein the refractive indexes satisfy a relation of n s ≧n a .
2. The method for producing an optical member according to claim 1 , wherein the layer having a refractive index n s contains silicon dioxide and titanium dioxide, and the layer contains silicon dioxide in an amount of 40 mol % or more and titanium dioxide in an amount of less than 40 mol %.
3. The method for producing an optical member according to claim 1 , wherein the layer containing aluminum oxide as a main component contains aluminum oxide in an amount of 50 mol % or more.
4. A method for producing an optical member, comprising:
forming a layer having a refractive index n s directly on a surface of a base having a refractive index n b wherein the refractive indexes satisfy a relation of n b ≧n s ,
thereafter, forming a layer containing aluminum oxide as a main component directly on the layer having a refractive index n s , the layer being formed by forming a gel layer containing aluminum oxide as a main component, and
subjecting the layer containing aluminum oxide as a main component to treatment with hot water, to thereby form a layer containing aluminum oxide as a main component, having a refractive index n a , and having an irregularity structure,
wherein the refractive indexes satisfy a relation of n s ≧n a .
5. The method for producing an optical member according to claim 4 , wherein the layer having a refractive index n s contains silicon dioxide and titanium dioxide, and the layer contains silicon dioxide in an amount of 40 mol % or more and titanium dioxide in an amount of less than 40 mol %.
6. The method for producing an optical member according to claim 4 , wherein the layer containing aluminum oxide as a main component contains aluminum oxide in an amount of 50 mol % or more.