# US 5,708,413 A · Head-up display apparatus

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- Number: US 5,708,413 A
- Document ID: US5708413A
- Status: Granted
- Kind: A
- Application number: 08/649,513
- Filed: 1996-05-17
- Granted: 1998-01-13
- Earliest claimed: 1995-05-18
- Assignees: Nippondenso Co., Ltd.; Asahi Glass Company, Limited; Toyota Jidosha Kabushiki Kaisha
- Inventors: Hideki Okuyama; Yasuo Hagisato; Kohichi Murata; Hiromi Sakurai
- Web page: https://patentgrep.com/patent/US5708413A

## CPC

- G02B 27/0103: {comprising holographic elements}
- G02B 2027/0129: {comprising devices for correcting parallax}
- G02B 2027/0154: {with movable elements}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

Liquid crystal display 1 has a surface disposed in parallel with a surface of holographic concave mirror 2. Liquid crystal display 1 causes a revolution about a display center "d" of holographic concave mirror 2 in a back-and-forth direction as indicated by arrow .alpha.. In response to such revolution around holographic concave mirror 2, liquid crystal display 1 causes an autorotation about its vertical center "e" in the back-and-forth direction as indicated by arrow .beta..

## Claims

### Claim 1

A head-up display apparatus comprising:
a light source for emitting light;
a display element disposed on an optical axis of said light source, for forming an image of said display element by said light emitted from said light source; and
a reflection plate for enlarging said image of said display element,
wherein a first angle between said optical axis and a surface of said display element is identical with a second angle between said optical axis and a surface of said reflection plate, and
said display element is rotatable about a predetermined rotational center spaced from said display element, said predetermined rotational center being arranged such that said display element is located between said predetermined rotational center and said reflection plate,
said rotational center being further arranged such that, within a rotational range of said display element, an intersection of said optical axis with said reflection plate remains stationary on said reflection plate.

### Claim 2

A head-up display apparatus comprising:
a light source for emitting light;
a display element disposed on an optical axis of said light source, for forming an image of said display element by said light emitted from said light source; and
a reflection plate for enlarging said image of said display element,
wherein said display element is rotatable about a predetermined rotational center spaced from said display element, said predetermined rotational center being arranged such that said display element is located between said predetermined rotational center and said reflection plate,
said rotational center being further arranged such that, within a rotational range of said display element, an intersection of said optical axis with said reflection plate remains stationary on said reflection plate.

### Claim 3 (depends on 2)

The head-up display apparatus in accordance with claim 2, wherein said display element causes an autorotation in response to a revolution around said reflection plate in such a manner that a first angle increases in accordance with an increase of a second angle, where said first angle is an angle between said optical axis and a surface of said display element while said second angle is an angle between said optical axis and a surface of said reflection plate.

### Claim 4 (depends on 2)

The head-up display apparatus in accordance with claim 2, wherein said reflection plate is a holographic concave mirror.

### Claim 5 (depends on 2)

The head-up display apparatus in accordance with claim 2, wherein said display element is a liquid crystal display.