Anti-reflection coating of optical part made of synthetic resin
First Claim
1. An anti-reflection coating of three layers for a synthetic resin substrate having a refractive index in the approximate range of 1.49 to 1.58, comprising:
- a first layer, at the air side, of silicon dioxide;
a second layer having an index of refraction of n2 ;
a third layer, adjacent the substrate, of ceric oxide, having an index of refraction of n3, andthe second layer and the third layer satisfying the following conditions, respectively;
1.50≦
n2 ≦
1.62,0.04λ
0 ≦
n2 d2 ≦
0.15λ
0,1.92≦
n3 ≦
2.10,0.02λ
0 ≦
n3 d3 ≦
0.50λ
0, wherein n2 d2 and n3 d3 are the optical thickness of the second layer and the third layer, respectively, and λ
0 is the dominant design wavelength.
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Abstract
An anti-reflection coating with n layers on an optical part substrate made of synthetic resin wherein n is 3, 4, or 5, and the first layer at the air side comprises silicon dioxide (SiO2), and the n-th layer on the surface of the synthetic resin comprises ceric oxide (CeO2) is excellent in reflection reducing effect and does not result in the age-based change of the refractive index. And that the very good adhesion of the reflection reducing coating with the substrate results in hardness of layer stripping.
Further an anti-reflection coating of the invention has reflection reducing effect in the near-infrared region.
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Citations
5 Claims
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1. An anti-reflection coating of three layers for a synthetic resin substrate having a refractive index in the approximate range of 1.49 to 1.58, comprising:
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a first layer, at the air side, of silicon dioxide; a second layer having an index of refraction of n2 ; a third layer, adjacent the substrate, of ceric oxide, having an index of refraction of n3, and the second layer and the third layer satisfying the following conditions, respectively; 1.50≦
n2 ≦
1.62,0.04λ
0 ≦
n2 d2 ≦
0.15λ
0,1.92≦
n3 ≦
2.10,0.02λ
0 ≦
n3 d3 ≦
0.50λ
0,wherein n2 d2 and n3 d3 are the optical thickness of the second layer and the third layer, respectively, and λ
0 is the dominant design wavelength. - View Dependent Claims (2)
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3. An anti-reflection coating of four layers for a synthetic resin substrate, comprising:
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a first layer, at the air side, of silicon dioxide; a second layer comprising a material selected from the group consisting of zirconium oxide, titanium dioxide, hafnium dioxide, ceric oxide, tantalum oxide, and a mixture of zirconium oxide and titanium oxide; a third layer selected from one of aluminum oxide and silicon dioxide, and a fourth layer, on the surface of the synthetic resin substrate, comprising ceric oxide having an index of refraction of n4, and the fourth layer satisfying the following equations; 1.92≦
n4 ≦
2.10,0<
n4 d4 ≦
0.25λ
0wherein n4 d4 is an optical thickness of the fourth layer and λ
0 is a dominant design wavelength. - View Dependent Claims (4)
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5. An anti-reflection coating of five layers for a synthetic resin substrate, comprising:
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a first layer, at the air side, of silicon dioxide; a second layer of aluminum oxide; a third layer of ceric oxide; a fourth layer of aluminum oxide, and a fifth layer, on the surface of the synthetic resin substrate, of ceric oxide having an index of refraction of n5, and the fifth layer satisfying the following equations; 1.92≦
n5 ≦
2.10,0.05λ
0 ≦
n5 d5 ≦
0.20λ
0,wherein n5 d5 is an optical thickness of the fifth layer and λ
0 is a dominant design wavelength.
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Specification