Diffraction grating light doubling collection system

• US 5,629,801 A
• Filed: 06/07/1995
• Issued: 05/13/1997
• Est. Priority Date: 06/07/1995
• Status: Expired due to Term

• Current Assignee: Silicon Light Machines Corporation (SCREEN Holdings Co., Ltd.)
• Original Assignee: Silicon Light Machines Corporation (SCREEN Holdings Co., Ltd.)
• Inventors: Staker, Bryan P., Bloom, David M., Loucks, Bryan E.
• Primary Examiner(s): Dzierzynski, Paul M.
• Assistant Examiner(s): CHANG, AUDREY Y
• Application Number:
  US08/473,759
• Time in Patent Office: 706 Days
• Field of Search: 359/40, 359/45, 359/558, 359/572, 359/263, 353/122, 353/82, 348/759
• US Class Current: 359/572
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0047 for use with a light source G02B19/009, G02B19/0095 take precedence; details of lighting devices in general F21V; non-semiconductor lasers having optical devices external to the laser cavity H01S3/005
• CPC Class Codes: G02B 26/0808 by means of one or more diffracting elements
• CPC Class Codes: G02B 27/42 Diffraction optics , i.e. systems including a diffractive element being designed for providing a diffractive effectG02B27/60 takes precedence
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]
• CPC Class Codes: H04N 9/31 Projection devices for colour picture display , e.g. using electronic spatial light modulators [ESLM]

Abstract

A reflective/diffractive light valve system collects light from multiple dimensions around a single light source. From these multiple collection dimensions, the light is directed to impinge on the valve from multiple directions. When the valve is configured to be reflective, the light returns to the source. On the other hand, when the valve is configured to be diffractive, light from a first and third order diffraction are transmitted from the valve for each of the collection dimensions which greatly enhances the efficiency of the system.

Claims

1. An optical system comprising:

a. a light source for generating light;

b. a light valve for receiving light from the light source, wherein the light valve is selectably configurable to operate in each of a reflecting mode and a diffracting mode;

c. means for collecting a first portion of the light in a first collection path;

d. means for directing the first portion of the light to the light valve via the first collection path;

e. means for collecting a second portion of the light in a second collection path; and

f. means for directing the second portion of the light to the light valve via the second collection path,

wherein the first portion of the light returns to the light source via the second path and the second portion of the light returns to the light source via the first path in the reflecting mode, and wherein first order diffractions of the first portion and the second portion of the light exit the system in the diffracting mode.

2. The optical system according to claim 1 wherein the light valve is a diffraction light valve.

3. The optical system according to claim 2 wherein the light valve is a grating light valve.

4. The optical system according to claim 2 wherein an angle of incidence is equal to a first order diffraction angle.

5. The optical system according to claim 2 wherein the means for directing the first portion of the light and the means for directing the second portion of the light comprise turning mirrors.

6. The optical system according to claim 5 wherein a second order diffraction is blocked by one of the turning mirrors.

7. The optical system according to claim 5 wherein the turning mirrors comprise a plurality of sub-mirrors which appear a single reflective surface to light traveling from the source to the light valve and appear a single reflective surface to light traveling from the light valve when the light valve is configured in the reflecting mode, and wherein odd order diffractions of the first portion and the second portion of the light exit the system when the light valve is configured in the diffracting mode.

8. The optical system according to claim 7 wherein an even order diffraction is blocked by a predetermined one of the turning mirrors.