# US 2008/0186457 A1 · Light source device and projector

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- Number: US 2008/0186457 A1
- Document ID: US20080186457A1
- Status: Published application
- Kind: A1
- Application number: 12/023,353
- Filed: 2008-01-31
- Published: 2008-08-07
- Earliest claimed: 2007-02-02
- Assignees: Seiko Epson Corporation
- Inventors: Yutaka TAKADA; Hiroyuki MOTEKI
- Web page: https://patentgrep.com/patent/US20080186457A1

## CPC

- G03B 21/28: Reflectors in projection beam {(in illumination beam G03B21/2066)}
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)

## Abstract

A light source device includes a microwave generating section for generating a microwave, a reflector connected to the microwave generating section, and a microwave electrodeless lamp disposed inside a cavity, the cavity including the reflector and a metallic chamber covering an opening section of the reflector. The chamber includes a tube member having an opening section for communicating the inside and the outside of the cavity to lead a light flux out of the chamber, and a bore diameter, D of the opening section, a length L of the tube member, a wavelength λ of the microwave, and a wavelength Λ of the light flux satisfy Λ<D≦(¼)λ, L≧(¼) λ, and D+L=(½)λ.

## Claims

### Claim 1

A light source device comprising:
a microwave generating section for generating a microwave;
a reflector connected to the microwave generating section; and
a microwave electrodeless lamp disposed inside a cavity, the cavity including the reflector and a metallic chamber covering an opening section of the reflector,
wherein the chamber includes a tube member having an opening section for communicating the inside and the outside of the cavity to lead a light flux out of the chamber, and
a bore diameter D of the opening section, a length L of the tube member, a wavelength λ of the microwave, and a wavelength Λ of the light flux satisfy Λ<D≦(¼)λ, L≧(¼)λ, and D+L=(½)λ.

### Claim 2 (depends on 1)

The light source device according to claim 1,
wherein the bore diameter D of the opening section is equal to (¼)λ, and the length L of the tube member is equal to (¼)λ.

### Claim 3 (depends on 1)

The light source device according to claim 1,
wherein at least inner surface of the tube member of the chamber is in a mirror surface condition.

### Claim 4 (depends on 1)

The light source device according to claim 1,
wherein the tube member is provided with an optical lens on an optical axis of a light flux emitted from the microwave electrodeless lamp.

### Claim 5 (depends on 4)

The light source device according to claim 4,
wherein the optical lens is attached to a tube like lens holder to form an optical lens unit and
the optical lens unit is attached to the tube member.

### Claim 6 (depends on 5)

The light source device according to claim 5,
wherein the optical lens unit is attached movably in the optical axis direction of the light flux emitted from the microwave electrodeless lamp.

### Claim 7

A projector comprising:
a light source device including
a microwave generating section for generating a microwave,
a reflector connected to the microwave generating section, and
a microwave electrodeless lamp disposed inside a cavity, the cavity including the reflector and a chamber covering an opening section of the reflector,
the chamber including a tube member having an opening section for communicating the inside and the outside of the cavity to lead a light flux out of the chamber, and
a bore diameter D of the opening section, a length L of the tube member, a wavelength λ of the microwave, and a wavelength Λ of the light flux satisfying Λ<D≦(¼)Λ, L≧(¼)λ, and D+L=(½)λ;
an optical modulation section for modulating light flux emitted from the light source device in accordance with input image information to form an optical image; and
a projection section for projecting the optical image formed by the optical modulation section.