# US 2012/0257280 A1 · Tunable interference filter, optical module, and electronic apparatus

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- Number: US 2012/0257280 A1
- Document ID: US20120257280A1
- Status: Published application
- Kind: A1
- Application number: 13/442,325
- Filed: 2012-04-09
- Published: 2012-10-11
- Earliest claimed: 2011-04-11
- Assignees: Seiko Epson Corporation
- Inventors: Akira SANO; Yasushi MATSUNO
- Web page: https://patentgrep.com/patent/US20120257280A1

## CPC

- 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)}
- G01J 3/26: using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
- G02B 5/28: Interference filters
- 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)}
- G02B 5/285: {comprising deposited thin solid films (G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N)

## Abstract

A tunable interference filter includes: first and second opposed substrates; a first reflection film provided on a first reflection film fixing surface of the first substrate; a second reflection film provided on a second reflection film fixing surface of the second substrate and separated from the first reflection film by a gap; and a first electrode provided on a first electrode surface of the first substrate facing the second substrate, wherein the first electrode surface is spaced apart from the second substrate by a different distance than the first reflection film fixing surface, and a layered part in which the first reflection film and the first electrode are stacked is provided on the first electrode surface, the layered part being spaced apart from the second substrate by a larger distance than the first reflection film fixing surface.

## Claims

### Claim 1

A tunable interference filter comprising:
a first substrate;
a second substrate opposed to the first substrate;
a first reflection film provided on a first reflection film fixing surface of the first substrate facing the second substrate;
a second reflection film provided on a second reflection film fixing surface of the second substrate facing the first substrate and opposing the first reflection film across a gap between the first and second reflection films; and
a first electrode provided on a first electrode surface of the first substrate facing the second substrate,
wherein the first electrode surface is spaced apart from the second substrate by a different distance than the first reflection film fixing surface, and
a layered part in which the first reflection film and the first electrode are stacked is provided on the first electrode surface, the layered part being spaced apart from the second substrate by a larger distance than the first reflection film fixing surface.

### Claim 2 (depends on 1)

The tunable interference filter according to claim 1, further comprising:
a second electrode provided on a second electrode surface of the second substrate facing the first substrate, and opposing the first electrode, the second electrode being spaced apart from the first electrode by a larger distance than the gap between the first and second reflection films, and
the layered part is formed by extending the first reflection film from the first reflection film fixing surface over the first electrode surface and stacking with an inner peripheral edge of the first electrode.

### Claim 3 (depends on 1)

The tunable interference filter according to claim 1, wherein the layered part is formed by stacking the first reflection film on the first electrode.

### Claim 4 (depends on 1)

The tunable interference filter according to claim 1, further comprising a reflection film connection electrode connected to the second reflection film.

### Claim 5 (depends on 1)

An optical module comprising:
the tunable interference filter according to claim 1; and
a detection unit that detects light extracted by the tunable interference filter.

### Claim 6 (depends on 5)

The optical module according to claim 5, wherein the tunable interference filter includes a reflection film connection electrode connected to the second reflection film,
the optical module further comprising a voltage control unit that controls the reflection film connection electrode and the first electrode at the same potential.

### Claim 7 (depends on 6)

The optical module according to claim 6, wherein the tunable interference filter includes a reflection film connection electrode connected to the second reflection film,
the optical module further comprising a voltage control unit that controls the reflection film connection electrode and the first electrode at the same potential.

### Claim 8 (depends on 5)

An electronic apparatus comprising the optical module according to claim 5.