# US 2014/0152962 A1 · Projection type display apparatus with increased life of optical constituent components

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- Number: US 2014/0152962 A1
- Document ID: US20140152962A1
- Status: Published application
- Kind: A1
- Application number: 14/176,209
- Filed: 2014-02-10
- Published: 2014-06-05
- Earliest claimed: 2010-10-25
- Assignees: Hitachi Consumer Electronics Co., Ltd.
- Applicants: Hitachi Consumer Electronics Co., Ltd.
- Inventors: Koji HIRATA; Nobuyuki KIMURA
- Web page: https://patentgrep.com/patent/US20140152962A1

## CPC

- G03B 21/2073: {Polarisers in the lamp house (peculiar to electronic spatial light modulators H04N9/3197)}
- G03B 21/14: Details
- G03B 21/208: {Homogenising, shaping of the illumination light}
- 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 projection type display apparatus including a light source, a display element, an illumination optical system and a projection lens to project a magnified image of the optical image. The illumination optical system includes a first array lens and a second array lens, each includes a plurality of lens elements arranged in a matrix, each of the lens elements having a rectangular opening, and a polarization conversion element having polarization conversion function by use of a plurality of polarized beam splitters and a plurality of half-wave phase plates, arranged in an array and opposing to the lens elements of the second array lens, to emit predetermined polarized light. The light source includes a light emitting plane of a rectangle or an ellipse shape, a longitudinal direction of the light emitting plane being parallel to a longitudinal direction of each opening of the polarization conversion element.

## Claims

### Claim 1

A projection type display apparatus, comprising:
a light source;
a display element;
an illumination optical system comprising a plurality of optical elements to enter light from the light source and to emit the light to the display element; and
a projection lens to magnify an optical image formed by the display element and to project a magnified image of the optical image,
wherein the illumination optical system comprises:
a first array lens and a second array lens each includes a plurality of lens elements arranged in a matrix, each of the lens elements having a rectangular shape opening and
a polarization conversion element having a polarization conversion function to convert a polarization direction of light incident thereon into a predetermined polarization direction of light and to emit polarized light by use of a plurality of polarized beam splitters and a plurality of half-wave phase plates, the beam splitters and the phase plates being arranged in an array and opposing to the lens elements of the second array lens, and
wherein the light source comprises a light emitting plane having substantially a rectangle or an ellipse shape, and
wherein a vertical direction of the shape of the light emitting plane is substantially parallel to the predetermined direction, and a longitudinal direction of the shape of the light emitting plane is substantially parallel to a longitudinal direction of an opening of the polarization conversion element.

### Claim 2 (depends on 1)

A projection type display apparatus according to claim 1, wherein, when a ratio of a longitudinal length of the display element to a vertical length thereof is M/N (M>N), a ratio of a length in the longitudinal direction of the light emitting plane of the light source to a length in the vertical direction thereof is less than (4N×N)/(M×M).

### Claim 3 (depends on 1)

A projection type display apparatus according to claim 1, wherein the light source comprises solid light emitting elements such as light emitting diodes, semiconductor lasers, and organic electroluminescence elements.

### Claim 4 (depends on 1)

A projection type display apparatus according to claim 1, wherein the light source comprises a light source having a phosphor which emits light exited by excitation light emitted from solid light emitting elements such as light emitting diodes, semiconductor lasers, and organic electroluminescence elements.

### Claim 5 (depends on 1)

A projection type display apparatus according to claim 1, wherein the light source comprises a light source having a diffusion layer which diffuses light from solid light emitting elements such as light emitting diodes, semiconductor lasers, and organic electroluminescence elements.