# US 10,310,364 B2 · Light source device and projection display apparatus

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- Number: US 10,310,364 B2
- Document ID: US10310364B2
- Status: Granted
- Kind: B2
- Application number: 15/944,451
- Filed: 2018-04-03
- Published: 2018-11-22
- Granted: 2019-06-04
- Earliest claimed: 2017-05-18
- Assignees: Panasonic Intellectual Property Management Co., Ltd.
- Applicants: Panasonic Intellectual Property Management Co., Ltd.
- Inventors: Manabu Okuno; Takaaki Tanaka
- Web page: https://patentgrep.com/patent/US10310364B2

## 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)}
- F21V 7/22: characterised by materials, surface treatments or coatings, e.g. dichroic reflectors
- F21V 13/14: the elements being filters or photoluminescent elements, reflectors and refractors
- G02B 5/0816: {Multilayer mirrors, i.e. having two or more reflecting layers (G02B5/0883, G02B5/0891 take precedence)}
- G02B 26/008: {in the form of devices for effecting sequential colour changes, e.g. colour wheels}
- G02B 27/141: {using dichroic mirrors}
- G02B 27/283: {used for beam splitting or combining}
- G02B 27/48: Laser speckle optics
- 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}
- F21S 10/007: {using rotating transparent or colored disks, e.g. gobo wheels}
- F21Y 2115/30: Semiconductor lasers
- 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)
- F21V: FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- F21S: NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
- F21Y: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED

## Abstract

The light source device and the projection display apparatus include a solid-state light source unit, a dichroic mirror, a fluorescent plate, a first wave plate, and a multi-reflection mirror. The solid-state light source unit emits first and second linearly polarized light rays at a predetermined ratio, the first and the second linearly polarized light rays being orthogonal to each other. The dichroic mirror separates the first and the second linearly polarized light rays, and combines blue light with yellow light. The fluorescent plate emits the yellow light to the dichroic mirror when the fluorescent plate is excited by the first linearly polarized light ray separated by the dichroic mirror. The first wave plate converts the second linearly polarized light ray separated by the dichroic mirror, into circularly polarized light. The multi-reflection mirror reflects the circularly polarized light to the dichroic mirror as the blue light.

## Claims

### Claim 1

A light source device comprising:
a solid-state light source unit configured to emit a linearly polarized light ray;
a dichroic mirror configured to separate the linearly polarized light ray into a first linearly polarized light ray and a second linearly polarized light ray, a polarization of the second linearly polarized light ray being orthogonal to a polarization of the first linearly polarized light ray;
a fluorescent plate configured to emit light to the dichroic mirror when the fluorescent plate is excited by the first linearly polarized light ray;
a first wave plate configured to convert the second linearly polarized light ray into circularly polarized light; and
a multi-reflection mirror configured to reflect the circularly polarized light through the first wave plate to the dichroic mirror.

### Claim 2 (depends on 1)

The light source device according to claim 1,
wherein the solid-state light source unit comprises:
a semiconductor laser light source configured to emit blue light; and
a second wave plate configured to emit the linearly polarized light ray by converting a polarization state of the blue light emitted from the semiconductor laser light source.

### Claim 3 (depends on 1)

The light source device according to claim 1, further comprising a light-condensing element configured to collect (i) the first linearly polarized light ray and (ii) the light emitted from the fluorescent plate.

### Claim 4 (depends on 1)

The light source device according to claim 1, further comprising a light-condensing element configured to collect (i) the second linearly polarized light ray and (ii) light obtained by the multi-reflection mirror reflecting the circularly polarized light through the first wave plate.

### Claim 5 (depends on 4)

The light source device according to claim 4, wherein the multi-reflection mirror is placed near a focal point of the light-condensing element.

### Claim 6 (depends on 4)

The light source device according to claim 4, wherein the first wave plate is placed between the multi-reflection mirror and the light-condensing element.

### Claim 7 (depends on 1)

The light source device according to claim 1, wherein the multi-reflection mirror has a predetermined incident surface with a reflectance of 20% to 50%, inclusive.

### Claim 8 (depends on 1)

The light source device according to claim 1, further comprising a diffuser placed between the dichroic mirror and the first wave plate.

### Claim 9 (depends on 1)

A projection display apparatus comprising the light source device according to claim 1.

### Claim 10 (depends on 1)

The light source device according to claim 1,
wherein the multi-reflection mirror includes a first surface and a second surface, and
wherein in the multi-reflection mirror, the circularly polarized light is reflected between the first surface and the second surface.

### Claim 11 (depends on 10)

The light source device according to claim 10, wherein the first surface of the multi-reflection mirror has a partial reflection coating, and the second surface of the multi-reflection mirror has a total reflection coating.

### Claim 12 (depends on 1)

The light source device according to claim 1,
wherein the light emitted by the fluorescent plate when the fluorescent plate is excited by the first linearly polarized light ray is yellow light,
wherein light obtained by the multi-reflection mirror reflecting the circularly polarized light through the first wave plate is blue light, and
wherein the dichroic mirror emits white light by combining (i) the yellow light emitted by the fluorescent plate when the fluorescent plate is excited by the first linearly polarized light ray with (ii) the blue light obtained by the multi-reflection mirror reflecting the circularly polarized light through the first wave plate.

### Claim 13 (depends on 1)

The light source device according to claim 1, wherein the first linearly polarized light ray is an s-polarized component of the linearly polarized light ray, and the second linearly polarized light ray is a p-polarized component of the linearly polarized light ray.