Anti-reflection coating and optical element having such anti-reflection coating for image sensors

• US 20060154044A1
• Filed: 01/04/2006
• Published: 07/13/2006
• Est. Priority Date: 01/07/2005
• Status: Abandoned Application

• Current Assignee: Pentax Corporation (Hoya Corporation)
• Original Assignee: Pentax Corporation (Hoya Corporation)
• Inventors: Nakayama, Hiroyuki, Yamada, Kazuhiro, Sakai, Yasuhiro, Yamada, Maki
• Application Number:
  US11/324,312
• Publication Number:
  US 20060154044A1
• Time in Patent Office: Days
• US Class Current: 428/312.200
• CPC Class Codes: C03C 17/007 containing a dispersed phase, e.g. particles, fibres or flakes, in a continuous phase
• CPC Class Codes: C03C 17/34 with at least two coatings having different compositions C03C17/44 takes precedence
• CPC Class Codes: C03C 17/3411 with at least two coatings of inorganic materials C03C17/36, C03C17/42 take precedence
• CPC Class Codes: C03C 17/3452 comprising a fluoride
• CPC Class Codes: C03C 2217/425 consisting of a porous layer
• CPC Class Codes: C03C 2217/732 made of a single layer
• CPC Class Codes: G02B 5/0247 by means of voids or pores
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/249967 Inorganic matrix in void-containing component

Abstract

An anti-reflection coating having a luminous reflectance of 2% or less to light at an incident angle of 0-60° and excellent scratch resistance, which comprises a dense layer and a porous silica aerogel layer formed in this order on a substrate such that a refractive index successively decreases from said substrate to said porous layer.

Claims

1. An anti-reflection coating comprising a dense layer and a porous silica aerogel layer formed in this order on a substrate such that a refractive index successively decreases from said substrate to said porous silica aerogel layer.

2. The anti-reflection coating according to claim 1, wherein said dense layer is an inorganic layer, a fine inorganic particles-binder composite layer or a resin layer.

3. The anti-reflection coating according to claim 2, wherein said inorganic layer is formed by a vapor deposition method.

4. The anti-reflection coating according to claim 3, wherein said vapor-deposited inorganic layer is made of magnesium fluoride or silicon oxide.

5. The anti-reflection coating according to claim 1, wherein said porous silica aerogel layer is formed by heat-treating an organic-modified silica aerogel layer.

6. The anti-reflection coating according to claim 1, wherein said porous silica aerogel layer has a refractive index of 1.05-1.35.

7. The anti-reflection coating according to claim 1, wherein said porous silica aerogel layer has a porosity of 30-90%.

8. The anti-reflection coating according to claim 1, wherein said porous silica aerogel layer has a contact angle of 15°

or less to pure water.

9. The anti-reflection coating according to claim 1, wherein said dense layer and said porous silica aerogel layer respectively have optical thickness in a range of λ

d/5−

λ

d/3, wherein λ

d is a designed wavelength.

10. The anti-reflection coating according to claim 1, wherein said anti-reflection coating has a luminous reflectance of 2% or less to light at an incident angle of 0-60°

in a wavelength range of said designed wavelength λ

d±

100 nm.

11. An optical element for image sensors, which comprises an anti-reflection coating comprising a dense layer and a porous silica aerogel layer formed in this order on a substrate such that a refractive index successively decreases from said substrate to said porous silica aerogel layer.