SURFACE PREPARATION METHOD FOR ELIMINATING OPTICAL INTERFERENCE FROM ABSORPTION CAVITY MIRRORS

• US 20100091290A1
• Filed: 10/01/2009
• Published: 04/15/2010
• Est. Priority Date: 07/11/2008
• Status: Active Grant

• Current Assignee: Li & S Company Limited (Yesco Holdings Co., Ltd.)
• Original Assignee: Li & S Company Limited (Yesco Holdings Co., Ltd.)
• Inventors: Anderson, Tyler
• Granted Patent: US 8,317,342 B2
• Time in Patent Office: Days
• US Class Current: 356/437
• CPC Class Codes: G01N 2021/0389 Windows
• CPC Class Codes: G01N 2021/152 Scraping; Brushing; Moving band
• CPC Class Codes: G01N 21/031 Multipass arrangements
• CPC Class Codes: G02B 5/0221 the surface having an irregular structure G02B5/0226 takes precedence
• CPC Class Codes: G02B 5/0284 used in reflection
• CPC Class Codes: G02B 5/08 Mirrors vehicle mirrors involving special optical features B60R1/08
• CPC Class Codes: G02B 5/0816 Multilayer mirrors, i.e. having two or more reflecting layers G02B5/0883, G02B5/0891 take precedence
• CPC Class Codes: G02B 5/0833 comprising inorganic materials only

Abstract

Optical mirror elements having a diffusive backing, methods for making such optical mirror elements, and devices incorporating such optical mirror elements. The optical mirror element typically includes a first, reflective surface, and a second surface having uneven or granular features, wherein light passing through the first surface is diffusely reflected by the uneven or granular features of the second surface. The optical mirror elements are particularly well suited for use in Herriott Cell arrangements in gas analyzers.

Claims

1. An optical mirror element, comprising:

a first, reflective surface; and

a second surface having uneven or granular features, wherein light passing through the first surface is diffusely reflected by the uneven or granular features of the second surface.

2. The optical mirror element of claim 1, wherein the first, reflective surface includes one or more layers of dielectric material.

3. The optical element of claim 1, wherein the uneven or granular features are formed by sandblasting the second surface.

4. The optical element of claim 1, wherein the uneven or granular features are formed by removing material from the second surface.

5. The optical element of claim 1, wherein the uneven or granular features are formed by adding material to the second surface.

6. The optical element of claim 1, wherein the optical mirror element is integrated in a gas analyzer.

7. A method of forming an optical mirror element having a diffuse backing, the method comprising:

applying a reflective coating to a first surface of an optical element so as to define a reflective surface; and

modifying a second surface of the optical element to define uneven or granular features, such that light passing though the first surface and impinging on the second surface is diffusely reflected by the uneven or granular features of the second surface.

9. The method of claim 7 or claim 8, wherein applying a reflective coating includes applying one or more layers of dielectric material.

10. The method of claim 7 or claim 8, wherein the optical element is an optically transmissive element.

11. The method of claim 7 or claim 8, wherein modifying includes sandblasting the second surface of the optical element.

12. The method of claim 7 or claim 8, wherein modifying includes removing material from the second surface of the optical element.

13. The method of claim 7 or claim 8, wherein modifying includes adding material to the second surface of the optical element.

14. The method of claim 7 or claim 8, wherein the optical element is an optically transmissive lens element.

8. A method of forming an optical mirror element having a diffuse backing, the method comprising:

applying a reflective coating to at least a portion of a first surface of an optical element so as to define a reflective surface; and

modifying at least a portion of a second surface of the optical element to define a diffuse reflector portion, such that light passing though the first surface and impinging on the second surface is diffusely reflected by the diffuse reflector portion of the second surface.

15. An optical cavity device, comprising:

a first mirror element having an internal reflective surface and an exterior surface having uneven or granular features, wherein light passing through the internal reflective surface is diffusely reflected by the uneven or granular features of the exterior surface; and

a second mirror element having an internal reflective surface and an exterior surface; and

a housing structure configured to hold the first and second mirrors such that the internal surfaces are facing each other along a common axis.

16. The optical cavity device of claim 15, wherein the exterior surface of the second mirror element has uneven or granular features, wherein light passing through the internal reflective surface of the second mirror element is diffusely reflected by the uneven or granular features of the exterior surface of the second mirror element.

17. The optical cavity device of claim 15, wherein the internal surfaces of both the first and second mirror elements have a concave geometry.

18. The optical cavity device of claim 15, wherein a first portion of the interior surface comprises a reflective coating defining a reflective surface, and wherein a second portion of the internal surface comprises an anti-reflective coating defining an optically transmissive window in the reflective surface.