INTERFERENCE FILTER, OPTICAL MODULE, AND OPTICAL ANALYZER

• US 20120127471A1
• Filed: 09/30/2011
• Published: 05/24/2012
• Est. Priority Date: 11/19/2010
• Status: Abandoned Application

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: URUSHIDANI, Tatsuo
• Application Number:
  US13/249,611
• Publication Number:
  US 20120127471A1
• Time in Patent Office: Days
• US Class Current: 356/450
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G02B 5/085 at least one of the reflecting layers comprising metal
• CPC Class Codes: G02B 5/281 designed for the infrared light
• CPC Class Codes: G02B 5/284 of etalon type comprising a resonant cavity other than a thin solid film, e.g. gas, air, solid plates etalons for fibre optic multiplexing G02B6/29358; etalons for spectral measurement G01J3/26

Abstract

An interference filter includes a fixed mirror and a movable mirror which are disposed so as to face each other with a gap therebetween. The fixed mirror is formed by laminating a one-layer TiO₂ film and a one-layer Ag alloy film. In addition, the movable mirror is formed by laminating a one-layer TiO₂ film and a one-layer Ag alloy film.

Claims

1. An interference filter comprising:

a first reflective film; and

a second reflective film disposed so as to face the first reflective film with a gap therebetween,

wherein the first reflective film is formed by laminating a one-layer transparent film and a one-layer metal film, and

the second reflective film is formed by laminating a one-layer transparent film and a one-layer metal film.

2. The interference filter according to claim 1, further comprising:

a first substrate; and

a second substrate facing the first substrate,

wherein the first reflective film is provided on a surface of the first substrate facing the second substrate and is formed by laminating the one-layer transparent film and the one-layer metal film sequentially from the first substrate side, and

the second reflective film is provided on the second substrate, faces the first reflective film with a predetermined gap therebetween, and is formed by laminating the one-layer transparent film and the one-layer metal film sequentially from the second substrate side.

3. The interference filter according to claim 1,

wherein the metal film is an Ag alloy film containing silver (Ag) as a main component.

4. The interference filter according to claim 3,

wherein the thickness of the Ag alloy film is equal to or larger than 30 nm and equal to or smaller than 60 nm.

5. The interference filter according to claim 1,

wherein the transparent film is a titanium dioxide (TiO₂) film.

6. The interference filter according to claim 1,

wherein assuming that the thickness of the transparent film is T, a measurement wavelength which is a wavelength of measurement light transmitted through the interference filter is λ

, and the refractive index of the transparent film at the measurement wavelength is r, the thickness T of the transparent film satisfies Expression T=λ

/4r, and

the thickness T₁ of the transparent film is set in a range of 0.85T≦

T₁≦

1.25T.

7. The interference filter according to claim 2,

wherein the first and second substrates are formed of glass with a different refractive index from that of the transparent film.

8. An optical module comprising:

the interference filter according to claim 1; and

a light receiving section which receives light to be examined which has been transmitted through the interference filter.

9. An optical analyzer comprising:

the optical module according to claim 8; and

an analysis processing section which analyzes optical characteristics of the light to be examined on the basis of light received by the light receiving section of the optical module.