OPTICAL DEVICE AND ANTIREFLECTION FILM

• US 20110033681A1
• Filed: 04/27/2009
• Published: 02/10/2011
• Est. Priority Date: 04/30/2008
• Status: Active Grant

• Current Assignee: Hoya Corporation
• Original Assignee: Hoya Corporation
• Inventors: Adachi, Makoto, Kawamata, Kazuo, Muraki, Tsuneo
• Granted Patent: US 8,481,148 B2
• Time in Patent Office: Days
• US Class Current: 428/212
• CPC Class Codes: G02B 1/115 Multilayers
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/2495 Thickness [relative or absolute]

Abstract

An antireflection film is formed by alternately laminating a low refractive index layer and a high refractive index layer. The antireflection film has a reflectance of 10% or less and an excitation purity range of 10% or less for visible light in a wavelength range from 380 nm to 780 nm incident at an incident angle ranging from 0° to 45° when regarding the direction perpendicular to the surface as 0°. The antireflection film inhibits a specific color tone from occurring in interference color of incident light coming from an oblique direction.

Claims

1. An optical element comprising:

an optically transparent substrate; and

an antireflection film formed on at least one surface of the substrate,

wherein the antireflection film is formed by alternately laminating a low refractive index layer and a high refractive index layer, and

wherein the antireflection film has a reflectance of 10% or less and an excitation purity range of 10% or less for visible light in a wavelength range from 380 nm to 780 nm incident at an incident angle ranging from 0°

to 45°

when regarding the direction perpendicular to the surface of the substrate as 0°

.

2. The optical element according to claim 1, wherein the first layer of the antireflection film from the side of the substrate is the low refractive index layer whose optical film thickness is within a range from 0.03 λ

to 0.1 λ

(λ

=500 nm).

3. The optical element according to claim 1, wherein the third layer of the antireflection film from the side of the substrate is the low refractive index layer whose optical film thickness is within a range from 0.1 λ

to 0.2 λ

(λ

=500 nm).

4. The optical element according to claim 1, wherein the material of the low refractive index layers of the antireflection film is silicon oxide, and the material of the high refractive index layers of the antireflection film is niobium oxide.

5. The optical element according to claim 1, wherein the refractive index of the substrate is within a range of from 1.5 to 1.8.

6. The optical element according to claim 1, further comparing a hard film formed between the antireflection film and the substrate.

7. An antireflection film comprising:

a low refractive index layer; and

a high refractive index layer,

wherein the antireflection film is formed by alternately laminating the low refractive index layer and the high refractive index layer, and

wherein the antireflection film has a reflectance of 10% or less and an excitation purity range of 10% or less for visible light in a wavelength range from 380 nm to 780 nm incident at an incident angle ranging from 0°

to 45°

when regarding the direction perpendicular to the surface of the substrate as 0°

.