# US 10,122,977 B2 · Projector including first and second optical systems

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 10,122,977 B2
- Document ID: US10122977B2
- Status: Granted
- Kind: B2
- Application number: 15/615,726
- Filed: 2017-06-06
- Published: 2017-09-21
- Granted: 2018-11-06
- Earliest claimed: 2017-06-06
- Assignees: NEC Display Solutions, Ltd.
- Applicants: NEC Display Solutions, Ltd.
- Inventors: Eisaku Shouji
- Web page: https://patentgrep.com/patent/US10122977B2

## CPC

- H04N 9/3158: {for controlling the spectrum}
- G02B 27/102: {for generating a colour image from monochromatic image signal sources}
- G02B 27/1033: {having a single light modulator for all colour channels}
- G02B 27/126: {The splitting element being a prism or prismatic array, including systems based on total internal reflection}
- G02B 27/141: {using dichroic mirrors}
- G03B 21/147: {Optical correction of image distortions, e.g. keystone}
- G03B 21/2013: {Plural light sources}
- G03B 21/204: {using secondary light emission, e.g. luminescence or fluorescence (using different colours G03B33/00; if related to video signals H04N9/3197)}
- G03B 21/208: {Homogenising, shaping of the illumination light}
- G03B 33/12: using beam-splitting or beam-combining systems, e.g. dichroic mirrors
- H04N 5/7458: {the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]}
- H04N 9/3105: {for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators (simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10)}
- H04N 9/3164: {using multiple light sources}
- H04N 9/317: {Convergence or focusing systems (electronic adjustment of convergence H04N9/3185; convergence or focusing arrangements for cathode ray tubes H04N9/28; means for automatic focusing of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/53)}
- G02B 26/0833: {the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD (G02B26/0825 takes precedence; micromechanical devices in general B81B)}
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- 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 projector includes: a light source that emits light of a first color and a second color; a first image formation element that forms a first image light of the first color; a second image formation element that forms a second image light of the second color; a projection lens that projects the first image light and the second image light to the outside; a first optical system that guides light of the first color that is emitted from the light source to the first image formation element, and guides light of the first color from the first image formation element to the projection lens; and a second optical system that guides light of the second color that is emitted from the light source to the second image formation element, and guides light of the second color from the second image formation element to the projection lens.

## Claims

### Claim 1

A projector comprising:
a light source that emits light of a first color and a second color;
a first image formation element that forms a first image light of said first color;
a second image formation element that forms a second image light of said second color;
a projection lens that projects said first image light and said second image light to the outside;
a first optical system that guides light of said first color that is emitted from said light source to said first image formation element, and guides light of said first color from said first image formation element to said projection lens; and
a second optical system that guides light of said second color that is emitted from said light source to said second image formation element, and guides light of said second color from said second image formation element to said projection lens;
wherein said first optical system has a convex lens between said first image formation element and said projection lens, and
wherein an f-number of said first optical system is greater than an f-number of said second optical system.

### Claim 2 (depends on 1)

The projector as set forth in claim 1, wherein:
said first optical system and said second optical system have a common separating/synthesizing optical system that synthesizes light of said first color from said first image formation element and light of said second color from said second color formation element; and
said first optical system has said convex lens between said separating/synthesizing optical system and said first image formation element.

### Claim 3

A projector comprising:
a first light source that emits light of a first color;
a second light source that emits light of a second color;
image forming units that adjust the intensity of light emitted from said first light source and said second light source on a per-pixel basis and form image light;
a projection lens that projects image light that is formed in said image forming units to the outside;
a first optical system that guides light of the first color that is emitted from said first light source to said projection lens, and has a first lens that is arranged between said first light source and said projection lens; and
a second optical system that guides light of the second color that is emitted from said second light source to said projection lens, and has a second lens that is arranged between said second light source and said projection lens;
wherein a curvature of said first lens and a curvature of said second lens are set such that a f-number of said first optical system is greater than a f-number of said second optical system.

### Claim 4 (depends on 3)

The projector as set forth in claim 3, further comprising:
a synthesizing optical system that synthesizes light of said first color and light of said second color;
wherein said first optical system has said first lens that is arranged between said first light source and said synthesizing optical system, and
wherein said second optical system has said second lens that is arranged between said second light source and said synthesizing optical system.

### Claim 5 (depends on 4)

The projector as set forth in claim 4, wherein said image forming units include a first image formation element that forms image light of said first color and a second image formation element that forms image light of said second color.

### Claim 6 (depends on 5)

The projector as set forth in claim 5, wherein:
said first optical system guides light of said first color to said first image formation element;
said second optical system guides light of said second color to said second image formation element; and
said first optical system and said second optical system have a common separating/synthesizing optical system that synthesizes light of said first color from said first image formation element and light of said second color from said second image formation element.

### Claim 7 (depends on 1)

The projector as set forth in claim 1, wherein said first image formation element and said second image formation element comprise digital micromirror devices.

### Claim 8 (depends on 2)

The projector as set forth in claim 2, wherein said separating/synthesizing optical system comprises a color prism.

### Claim 9 (depends on 2)

The projector as set forth in claim 2, further comprising:
an integrator that transmits synthesized light of said first wavelength and light of said second wavelength;
wherein the light paths of said synthesized light from said integrator to said separating/synthesizing optical system are identical.

### Claim 10 (depends on 1)

The projector as set forth in claim 1, wherein said first optical system and said second optical system partially have common optical components.

### Claim 11 (depends on 1)

The projector as set forth in claim 1, wherein:
light of said first wavelength comprises red light; and
light of said second wavelength comprises green light, blue light, or synthesized light of green light and blue light.