High-reflectance silver mirror and reflecting optical element

• US 6,695,458 B2
• Filed: 09/07/2001
• Issued: 02/24/2004
• Est. Priority Date: 09/12/2000
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Hatakeyama, Hideyuki, Ohgane, Masanobu
• Primary Examiner(s): Shafer, Ricky D.
• Application Number:
  US09/947,713
• Publication Number:
  US 20020054959A1
• Time in Patent Office: 900 Days
• Field of Search: 359/871, 359/883, 359/900, 427/162, 427/165, 427/166, 427/167
• US Class Current: 359/883
• CPC Class Codes: C03C 17/36 at least one coating being a metal
• CPC Class Codes: C03C 17/3607 Coatings of the type glass/inorganic compound/metal
• CPC Class Codes: C03C 17/3663 specially adapted for use as mirrors
• CPC Class Codes: G02B 5/08 Mirrors vehicle mirrors involving special optical features B60R1/08
• CPC Class Codes: Y10S 359/90 Methods

Abstract

A high-reflectance silver mirror has a high-reflectance film comprising a silver layer formed on a base material made of phosphorus-containing glass. The high-reflectance film is formed by a wet film-forming process on an acid-resistant protection film covering the base material. A reflecting optical element employing the high-reflectance silver mirror, and a process for producing the high-reflectance silver mirror are also provided. The high-reflectance silver mirror is producible at a reduced cost and has improved reflectivity.

Claims

1. A high-reflectance silver mirror comprising a base material made of phosphorus-containing glass and a high-reflectance film comprising a silver layer formed thereon, the high-reflectance film being formed by a wet film-forming method on an acid-resistant protection film provided on the base material.

2. The high-reflectance silver mirror according to claim 1, wherein the wet film-forming method is an electroless plating process.

3. The high-reflectance silver mirror according to claim 1, wherein the acid-resistant protection film is formed by a wet film-forming method.

4. The high-reflectance silver mirror according to claim 1, wherein the acid-resistant protection film is formed by applying a solution containing a metal alkoxide or a metal alkoxide hydrolyzate onto the base material to form a coating layer, followed by heating and baking the coating layer.

5. The high-reflectance silver mirror according to claim 1, wherein an interlayer is provided comprising at least a higher-refractivity thin film and a lower-refractivity thin film superposed in this order from the side of the base material between the base material and the silver layer, and at least the thin film contacting with a silver layer-forming solution has acid resistance.

6. The high-reflectance silver mirror according to claim 1, wherein a lower-refractivity thin film and a higher-refractivity thin film are superposed in this order as an upper layer on the silver layer.

7. The high-reflectance silver mirror according to claim 1, wherein the front face or the back face of the silver layer has a reflectivity (R) in the range of 89.0%<

R<

99.5% in the wavelength range from 400 nm to 900 nm, and the thin silver layer has a thickness (d) in the range of 0.1 μ

m<

d<

1 μ

m.

8. A reflecting optical element having a light travel path and a light reflection face provided in the light travel path, the light reflection face comprising a high-reflectance silver mirror as set forth in any one of claims 1 to 7.

9. A process for producing a high-reflectance silver mirror comprising a base material made of phosphorus-containing glass and a high-reflectance film comprising a silver layer formed thereon, comprising the steps of:

coating the base material with an acid-resistant protection film, and

forming the high-reflectance film on the acid-resistance protection film by a wet film-forming method.

10. The process according to claim 9, wherein the wet film-forming method is an electroless plating process.

11. The process according to claim 9, wherein the acid-resistant protection film is formed by a wet film-forming method.

12. The process according to claim 9, wherein the acid-resistant protection film is formed by applying a solution containing a metal alkoxide or a metal alkoxide hydrolyzate onto the base material to form a coating layer, followed by heating and baking the coating layer.

13. The process according to claim 9, wherein an interlayer is provided comprising at least a higher-refractivity thin film and a lower-refractivity thin film superposed in this order from the side of the base material between the base material and the silver layer, and at least the thin film contacting with a silver layer-forming solution has acid resistance.

14. The process according to claim 9, wherein a lower-refractivity thin film and a higher-refractivity thin film are superposed in this order as an upper layer on the silver layer.

15. The process according to claim 9, wherein the front face or the back face of the silver layer has a reflectivity (R) in the range of 89.0%<

R<

99.5% in the wavelength range from 400 nm to 900 nm, and the thin silver layer has a thickness (d) in the range of 0.1 μ

m<

d<

1 μ

m.