Lighting device and display device using the lighting device

• US 5,704,703 A
• Filed: 03/13/1997
• Issued: 01/06/1998
• Est. Priority Date: 03/03/1993
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Fujitsu Limited
• Inventors: Yamada, Fumiaki, Nittou, Eiji, Miyahara, Masaki, Nagatani, Shinpei
• Primary Examiner(s): Husar, Stephen F.
• Application Number:
  US08/816,489
• Time in Patent Office: 299 Days
• Field of Search: 362/26, 362/27, 362/31, 362/328, 362/329, 362/330, 362/331, 362/339, 349/65
• US Class Current: 362/27
• CPC Class Codes: B60Q 3/14 lighting through the surface to be illuminated
• CPC Class Codes: B60Q 3/64 for a single lighting device
• CPC Class Codes: G01D 11/28 Structurally-combined illuminating devices
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• 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 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0076 Stacked arrangements of multiple light guides of the same or different cross-sectional area
• CPC Class Codes: G02B 6/0078 Side-by-side arrangements, e.g. for large area displays

Abstract

A lighting device includes a light source, a light conducting plate having an incident surface receiving light emitted from the light source, a back surface and a light-emitting surface, and a reflection member having a first portion facing the back surface, and a second portion located on a side opposite to a side of the light conducting plate on which the light source is located. The second portion is spaced apart from the light conducting plate so that light emitted from the light conducting plate is oriented toward an emission surface of the lighting device.

Claims

1. A lighting device comprising:

a plurality of units with each unit of the plurality of units respectively comprising;

a light source;

a light conducting plate, having an incident surface receiving light emitted from the light source, a back surface, a light-emitting surface and an edge opposite to the incident surface, the light conducting plate having a substantially triangular shape; and

a reflection member facing the back surface of the light conducting plate,

wherein the edge opposite to the incident surface has no surface parallel to the incident surface.

2. The lighting device as claimed in claim 1, wherein the light conducting plates are arranged so that a space is defined by edges of the light conducting plates.

3. The lighting device as claimed in claim 1, wherein the light-emitting surface of each of the light conducting plates comprises an inclined surface which goes down toward the second portion of the reflection member.

4. The lighting device as claimed in claim 1, wherein:

the light-emitting surface of each of the light conducting plates comprises a first inclined surface which goes down toward the second portion of the reflection member, and a second inclined surface which goes down toward the second portion of the reflection member;

the first inclined surface continues to the second inclined surface; and

an inclined angle of the second inclined surface is greater than that of the first inclined surface.

5. The lighting device as claimed in claim 1, wherein the back surface of each light conducting plate includes a diffusion surface.

6. The light device as claimed in claim 1, further comprising:

a first linear prism plate partially allowing the lights emitted from the light conducting plates to pass through the first linear prism plate and partially reflecting said lights toward a space between the light conducting plates and the first linear prism plate; and

a second linear prism plate collecting the lights from the first linear prism plate in a normal-line direction on the emission surface.

7. The lighting device as claimed in claim 6, wherein the first linear prism plate comprises a plurality of different linear prisms.

8. A lighting device as recited in claim 1, further comprising:

at least one linear prism plate provided for the plurality of units,

wherein the light-emitting surface of said each light conducting plate has an inclined surface, and wherein said at least one linear prism plate receives light from the inclined surface of the light conducting plate.

9. The lighting device as claimed in claim 8, wherein the light conducting plates are arranged so that a space is defined by edges of the light conducting plates.

10. The lighting device as claimed in claim 8, wherein the light-emitting surface of each of the light conducting plates comprises an inclined surface which goes down toward the second portion of the reflection member.

11. The lighting device as claimed in claim 8, wherein the back surface of each light conducting plate includes a diffusion surface.

12. The light device as claimed in claim 8, further comprising:

a first linear prism plate partially allowing the light emitted from the light conducting plates to pass through the first linear prism plate and partially reflecting said light toward a space between the light conducting plates and the first linear prism plate; and

a second linear prism plate collecting the light from the first linear prism plate in a normal-line direction on the emission surface.

13. The lighting device as claimed in claim 12, wherein the first linear prism plate comprises a plurality of different linear prisms.

14. A lighting device comprising:

a plurality of units located;

the plurality of units respectively comprising;

light sources;

light conducting plates, each having an incident surface receiving light emitted from the light sources, a back surface, a light-emitting surface and an edge opposite to the incident surface;

a reflection member facing the back surfaces of the light conducting plate;

light diffusing means, formed on the back surface of each of the light conducting plates, for diffusing light traveling in each of the light conducting plates in the vicinity of the incident surface more greatly than in other portions of each of the light conducting plates;

a first linear prism plate partially allowing the lights emitted from the light conducting plates to pass through the first linear prism plate and partially reflecting said lights toward a space between the light conducting plates and the first linear prism plate; and

a second linear prism plate collecting the lights from the first linear prism plate in a normal-line direction on the emission surface,

wherein;

the light conducting plates are arranged so that a space is defined by edges of the light conducting plates; and

the light-emitting surface of each of the light conducting plates comprises an inclined surface which goes down toward the second portion of the reflection member.

15. The lighting device as claimed in claim 14, wherein said light diffusing means comprises elements for diffusion are arranged with a density higher than that with which elements of the light diffusing means are arranged in said other portions of each of the light conducting plates.

16. The lighting device as claimed in claim 14, wherein:

said first linear prism plate comprises first prisms and second prisms arranged with a predetermined ratio of a number of the first prisms to that of the second prisms; and

the first prisms and the second prisms face the light conducting plates.

17. The lighting device as claimed in claim 14, wherein:

the first linear prism plate comprises a Lenticular plate having first lenses having a first height and a first radius, and second lenses having a second height and a second radius;

the first height is less than the second height;

the first radius is greater than the second height; and

the first lenses and the second lenses are arranged with a predetermined ratio of a number of the first lenses to that of the second lenses.

18. The lighting device as claimed in claim 16, wherein the first prisms and the second prisms extend in a direction which is not parallel to nor vertical to the light source which comprises a linear light source.

19. The lighting device as claimed in claim 16, wherein the second linear prism plate comprises linear prisms extending in a direction which is not parallel to nor vertical to the light source which comprises a linear source.