Illumination device

• US 4,737,896 A
• Filed: 07/21/1986
• Issued: 04/12/1988
• Est. Priority Date: 07/23/1985
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kawai, Tatsundo, Yoshida, Akio, Ogura, Makoto, Mochizuki, Noritaka
• Primary Examiner(s): Jones, Larry
• Application Number:
  US06/887,423
• Time in Patent Office: 631 Days
• Field of Search: 362/300, 362/296, 362/299, 362/301, 362/308, 362/309, 362/326, 362/329, 362/335, 362/337, 362/339, 362/328, 362/23, 350/345, 350/330, 340/784, 340/765
• US Class Current: 362/301
• CPC Class Codes: F21V 13/04 the elements being reflectors and refractors for vehicle rear lights F21S43/40
• CPC Class Codes: F21V 7/00 Reflectors for light sources characterised by cooling arrangements F21V29/505
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements
• CPC Class Codes: G02B 6/003 Lens or lenticular sheet or layer
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/007 Incandescent lamp or gas discharge lamp
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G09F 13/0422 Reflectors
• CPC Class Codes: G09F 2013/145 curved reflectors

Abstract

An illumination device is provided which comprises a light source, a first light-deflecting means for converting the rays emitted from the light source into parallel rays and a second light-deflecting means for directing the parallel rays to an object to be illuminated.

Claims

1. An illumination device comprising:

a. a light source;

b. a display panel having picture elements arranged in rows and columns, each of the picture elements being independently controlled to be either in an open state or in a closed state;

c. A first light-deflecting means for converting the rays emitted from the light source into parallel rays; and

d. a second light-deflecting means having a reflection plane for directing the parallel rays to the display panel, the reflection plane being formed by a prism array, and the pitch between the prisms in the prism array being smaller than the pitch between the image elements in the display panel.

2. An illumination device according to claim 1, wherein the first light-deflecting means is a convex lens, and the light source is placed at the focal point of the convex lens.

3. An illumination device according to claim 1, wherein prism faces of the prism array inclined in the parallel rays are inclined at the angle of 45°

or less relative to the optical axis of the parallel rays.

4. An illumination device according to claim 1, wherein the second light-deflecting means comprises a light scattering plane for converting the parallel rays reflected by the reflection plane into scattered light.

5. An illumination device according to claim 1, wherein the reflection plane is curved.

6. An illumination device according to claim 1, wherein the second light-deflecting means is made of glass.

7. An illumination device according to claim 1, wherein the reflection plane is formed of a prism array, and the prism array is coated by reflective metal film.

8. An illumination device according to claim 1, wherein the display panel comprises ferroelectric liquid crystal.

9. An illumination device according to claim 1, wherein the display panel comprises twisted nematic liquid crystal.

10. An illumination device comprising:

a. a first light source and a second light source;

b. a display panel having picture elements arranged in rows and columns, each of the picture elements being independently controlled to be either in an open state or in a closed state;

c. a first light-deflecting means for converting the light emitted from the first light source into a first set of parallel rays, and a second light-deflecting means for converting the light emitted from the second light source into a second set of parallel rays;

d. a third light-deflecting means having a first reflection plane for directing the first set of parallel rays to the display panel, the first reflection plane being formed by a prism array; and

e. a fourth light-deflecting means having a second reflection plane for directing the second set of parallel rays to the display panel, the second reflection plane being formed by a second prism array, and the second reflection plane being placed in a position in which the reflected rays from the second reflection plane illuminates the display panel through the third light deflecting means.

11. An illumination device according to claim 10, wherein the first and second light deflecting means are respectively a first and a second convex lenses, and the first and the second light sources are placed respectively at the focal points of the first and the second convex lenses.

12. An illumination device according to claim 10, wherein the prisms faces of the first prism array inclined to the first set of parallel rays are inclined at the angle of 45°

or less relative to the optical axis of the first set of parallel rays, and the prism faces of the second prism array inclined to the second set of parallel rays are inclined at the angle of 45°

or less relative to the optical axis of the second set of parallel rays.

13. An illumination device according to claim 10, wherein the third light-deflecting means comprises a light scattering plane for converting the rays reflected by the first and the second reflection planes into scattered light.

14. An illumination device according to claim 10, wherein the pitch between the prism in the first prism array is smaller than the pitch in the image elements of the display panel.