# US 11,079,664 B2 · Optical system and image projection apparatus

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- Number: US 11,079,664 B2
- Document ID: US11079664B2
- Status: Granted
- Kind: B2
- Application number: 16/835,320
- Filed: 2020-03-31
- Published: 2020-11-12
- Granted: 2021-08-03
- Earliest claimed: 2019-05-10
- Assignees: Ricoh Company, Ltd.
- Applicants: Kei Adachi; Yukako Yamaguchi
- Inventors: Kei Adachi; Yukako Yamaguchi
- Web page: https://patentgrep.com/patent/US11079664B2

## CPC

- G03B 21/2006: {characterised by the light source}
- G03B 21/208: {Homogenising, shaping of the illumination light}
- G02B 27/0961: {Lens arrays (lens arrays per se G02B3/0006)}
- G03B 21/2066: {Reflectors in illumination beam (in projection beam G03B21/28)}
- H04N 9/3152: {for shaping the light beam (beam shaping per se G02B27/09)}
- G03B 21/005: {Projectors using an electronic spatial light modulator but not peculiar thereto}
- 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)
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An optical system includes a light source, an illumination optical system, and an optical modulator. The lens array and the lens of the illumination optical system are arranged in that order from an upstream side of an optical path of light from the light source. The light shield is disposed at the upstream side relative to the lens in the optical path. The light shield blocks some rays incident within a range of an effective diameter of the lens. The illumination optical system emits the light to the optical modulator. The optical modulator emits the incident light to a first direction and a second direction different from the first direction. A center of an effective diameter of the lens array is offset from a center of the effective diameter of the lens to an opposite side of the light shield in a direction orthogonal to the optical axis.

## Claims

### Claim 1

An optical system, comprising:
a light source configured to emit light;
an optical modulator; and
an illumination optical system configured to emit the light to the optical modulator, the illumination optical system including:
a lens;
a lens array on an upstream side of the lens in an optical path of the light emitted from the light source; and
a light shield on the upstream side of the lens in the optical path, the light shield configured to block light rays of the light incident within a range of a first effective diameter of the lens, wherein
the optical modulator is configured to emit the light incident on the optical modulator, in a first direction and in a second direction different from the first direction, and
a center of a second effective diameter of the lens array is offset, in a direction orthogonal to an optical axis of the illumination optical system, from a center of the first effective diameter of the lens and away from the light shield.

### Claim 2 (depends on 1)

The optical system according to claim 1, wherein
the lens array is disposed along the optical axis, and
the light shield is disposed, in the direction orthogonal to the optical axis, outside of the lens array and a distance away from the optical axis.

### Claim 3 (depends on 1)

The optical system according to claim 1, further comprising:
an urging member configured to urge one end of the lens array in the direction orthogonal to the optical axis; and
an abutting member having a contact surface that the other end of the lens array is abutted against in the direction orthogonal to the optical axis.

### Claim 4 (depends on 3)

The optical system according to claim 3, wherein
the urging member is disposed on a light shield side of the lens array in the direction orthogonal to the optical axis, and
the contact surface is on an opposite side of the light shield in the direction orthogonal to the optical axis.

### Claim 5 (depends on 3)

The optical system according to claim 3, wherein
the urging member is disposed on an opposite side of the light shield in the direction orthogonal to the optical axis so that the lens array is between the urging member and the light shield, and
the contact surface is on a light shield side in the direction orthogonal to the optical axis.

### Claim 6 (depends on 1)

The optical system according to claim 1, wherein
the lens array includes a first fly-eye lens and a second fly-eye lens, and
the first fly-eye lens is spaced apart from the second fly-eye lens along the optical axis.

### Claim 7 (depends on 1)

The optical system according to claim 1, further comprising an optical element configured to:
transmit the first light emitted from the optical modulator, and
reflect the second light emitted from the optical modulator.

### Claim 8 (depends on 7)

The optical system according to claim 7, further comprising a projection optical system configured to receive and project the first light transmitted through the optical element toward a projection target.

### Claim 9 (depends on 1)

An image projection apparatus comprising the optical system according to claim 1.

### Claim 10 (depends on 1)

The optical system according to claim 1, further comprising a field lens.

### Claim 11 (depends on 7)

The optical system according to claim 7, further comprising:
a field lens, wherein
the light emitted from the illumination optical system passes through the field lens to the optical element.

### Claim 12 (depends on 1)

The optical system according to claim 1, wherein the first effective diameter is larger than the second effective diameter.

### Claim 13

An optical system, comprising:
an optical modulator; and
an illumination optical system configured to emit light to the optical modulator, the illumination optical system including:
a lens;
a lens array on an upstream side of the lens in an optical path of the light; and
a light shield on the upstream side of the lens in the optical path, the light shield configured to block light rays of the light incident within a range of a first effective diameter of the lens, wherein
the optical modulator is configured to emit the light, incident on the optical modulator, in a first direction and in a second direction different from the first direction, and
a center of a second effective diameter of the lens array is offset, in a direction orthogonal to an optical axis of the illumination optical system, from a center of the first effective diameter of the lens and away from the light shield.

### Claim 14 (depends on 13)

The optical system according to claim 13, wherein
the lens array is disposed along the optical axis, and
the light shield is disposed, in the direction orthogonal to the optical axis, outside of the lens array and a distance away from the optical axis.

### Claim 15 (depends on 13)

The optical system according to claim 13, further comprising:
an urging member configured to urge one end of the lens array in the direction orthogonal to the optical axis; and
an abutting member having a contact surface that the other end of the lens array is abutted against in the direction orthogonal to the optical axis.

### Claim 16 (depends on 15)

The optical system according to claim 15, wherein
the urging member is disposed on a light shield side of the lens array in the direction orthogonal to the optical axis, and
the contact surface is on an opposite side of the light shield in the direction orthogonal to the optical axis.

### Claim 17 (depends on 15)

The optical system according to claim 15, wherein
the urging member is disposed on an opposite side of the light shield in the direction orthogonal to the optical axis so that the lens array is between the urging member and the light shield, and
the contact surface is on a light shield side in the direction orthogonal to the optical axis.

### Claim 18 (depends on 13)

The optical system according to claim 13, wherein
the lens array includes a first fly-eye lens and a second fly-eye lens, and
the first fly-eye lens is spaced apart from the second fly-eye lens along the optical axis.

### Claim 19 (depends on 13)

The optical system according to claim 13, further comprising an optical element configured to:
transmit the first light emitted from the optical modulator, and
reflect the second light emitted from the optical modulator.

### Claim 20 (depends on 19)

The optical system according to claim 19, further comprising a projection optical system configured to receive and project the first light transmitted through the optical element toward a projection target.