# US 11,442,347 B2 · Light source device having rotating wheel and image projection apparatus including the same

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- Number: US 11,442,347 B2
- Document ID: US11442347B2
- Status: Granted
- Kind: B2
- Application number: 16/926,354
- Filed: 2020-07-10
- Published: 2021-01-21
- Granted: 2022-09-13
- Earliest claimed: 2019-07-16
- Assignees: Canon Kabushiki Kaisha
- Applicants: Canon Kabushiki Kaisha
- Inventors: Tomohiro Nakamura
- Web page: https://patentgrep.com/patent/US11442347B2

## CPC

- G03B 21/204: {using secondary light emission, e.g. luminescence or fluorescence (using different colours G03B33/00; if related to video signals H04N9/3197)}
- G02B 26/008: {in the form of devices for effecting sequential colour changes, e.g. colour wheels}
- G02B 27/1046: {for use with transmissive spatial light modulators}
- G02B 27/141: {using dichroic mirrors}
- G03B 21/2013: {Plural light sources}
- G03B 21/2066: {Reflectors in illumination beam (in projection beam G03B21/28)}
- G03B 21/2073: {Polarisers in the lamp house (peculiar to electronic spatial light modulators 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 9/3158: {for controlling the spectrum}
- H04N 9/3161: {using laser light sources (using laser beams scanning the display screen H04N9/3129)}
- H04N 9/3164: {using multiple light sources}
- H04N 9/3167: {for polarizing the light beam (polarizing optical systems per se G02B27/28)}
- H10H 20/851: Wavelength conversion means
- 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
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS

## Abstract

A light source device includes a light source unit and a rotating wheel. The light source unit is configured to emit first blue light and second blue light. The rotating wheel includes a diffuser layer configured to diffuse and transmit the first blue light, and a phosphor layer configured to convert at least a part of the second blue light into yellow light.

## Claims

### Claim 1

A light source device comprising:
a light source unit configured to emit first blue light and second blue light; and
a rotating wheel including a diffusion element provided in an annular shape and configured to diffuse and transmit the first blue light, and a wavelength conversion element provided in an annular shape and configured to convert at least a part of the second blue light into yellow light.

### Claim 2 (depends on 1)

The light source device according to claim 1,
wherein the light source unit is disposed on a base member, and
wherein the light source unit include a first light source unit configured to emit the first blue light, and
a second light source unit configured to emit the second blue light and different from the first light source unit in position where the second light source unit is disposed on the base member.

### Claim 3 (depends on 1)

The light source device according to claim 1, further comprising a separating element configured to separate blue light emitted from the light source unit into the first blue light and the second blue light.

### Claim 4 (depends on 1)

The light source device according to claim 1, further comprising a first combining element configured to combine the light from the diffusion element and the light from the wavelength conversion element,
wherein the first combining element has a property of transmitting the light emitted from the diffusion element and reflecting the light from the wavelength conversion element.

### Claim 5 (depends on 1)

The light source device according to claim 1, further comprising:
a first combining element configured to combine the light from the diffusion element and the light from the wavelength conversion element;
a third light source unit configured to emit near-infrared light; and
a second combining element configured to combine the light from the diffusion element and the light emitted from the third light source unit,
wherein the first combining element has a property of transmitting the light emitted from the diffusion element and the light emitted from the third light source unit and reflecting the light from the wavelength conversion element.

### Claim 6 (depends on 2)

The light source device according to claim 2, further comprising:
a fourth light source unit configured to emit third blue light; and
a third combining element configured to combine the light emitted from the second light source unit and the light emitted from the fourth light source unit.

### Claim 7 (depends on 6)

The light source device according to claim 6,
wherein the third combining element is a polarized light separating element, and
wherein a polarization direction of the third blue light is different from a polarization direction of the second blue light.

### Claim 8 (depends on 6)

The light source device according to claim 6,
wherein the third combining element is a polarized light separating element,
wherein a polarization direction of the third blue light is the same as a polarization direction of the second blue light, and
wherein a half-wave plate is disposed on an optical path from the fourth light source unit to the polarized light separating element.

### Claim 9 (depends on 1)

The light source device according to claim 1,
wherein the rotating wheel includes a circular plate-like rotating plate, and
wherein the diffusion element and the wavelength conversion element are disposed on the rotating plate.

### Claim 10 (depends on 1)

The light source device according to claim 1, wherein the wavelength conversion element is disposed at an inner side with respect to the diffusion element.

### Claim 11 (depends on 1)

The light source device according to claim 1,
wherein the diffusion element has a circular plate shape,
wherein the wavelength conversion element has an annular shape, and
wherein the wavelength conversion element is disposed in the diffusion element.

### Claim 12 (depends on 2)

The light source device according to claim 2, further comprising a first afocal lens unit configured to compress the second blue light.

### Claim 13 (depends on 2)

The light source device according to claim 2, further comprising a second afocal lens unit configured to enlarge the first blue light.

### Claim 14 (depends on 1)

The light source device according to claim 1, further comprising:
a first condenser lens unit configured to guide the first blue light to the diffusion element;
a collimator lens unit configured to convert the light from the diffusion element into parallel light; and
a second condenser lens unit configured to guide the second blue light to the wavelength conversion element.

### Claim 15 (depends on 14)

The light source device according to claim 14, wherein
1.2≤f1/f2≤10
is satisfied, where a focal length of the collimator lens unit is f1, and a focal length of the second condenser lens unit is f2.

### Claim 16 (depends on 15)

The light source device according to claim 15, wherein
2.0≤f1/f2≤6.0
is further satisfied.

### Claim 17 (depends on 1)

The light source device according to claim 1, wherein
1°≤Φ≤30°
is satisfied, where a diffusion angle of the diffusion element is Φ.

### Claim 18 (depends on 17)

The light source device according to claim 17, wherein
1°≤Φ≤15°
is further satisfied.

### Claim 19

An image projection apparatus comprising:
a light source device;
a light modulation element; and
a lens holding unit configured to hold a projection lens configured to guide light from the light modulation element to a projection target surface,
wherein the light source device comprising:
a light source unit configured to emit first blue light and second blue light; and
a rotating wheel including a diffusion element provided in an annular shape and configured to diffuse and transmit the first blue light, and a wavelength conversion element provided in an annular shape and configured to convert at least a part of the second blue light into yellow light.