Display device and backlight device having plural solid-state emitting element units each emitting at least three colors and contained within a cylindrical air-filled light guide body also surrounded by air

• US 7,554,625 B2
• Filed: 05/24/2005
• Issued: 06/30/2009
• Est. Priority Date: 05/24/2004
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Hitachi Display Devices Limited (Hitachi, Ltd.), Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Koganezawa, Nobuyuki
• Primary Examiner(s): Nelms; David
• Assistant Examiner(s): HEYMAN, JOHN S
• Application Number:
  US11/135,295
• Publication Number:
  US 20050259195A1
• Time in Patent Office: 1,498 Days
• Field of Search: 349/61, 349/62, 349/64, 349/67, 349/159, 349/160, 362/555, 362/612
• US Class Current: 349/61
• CPC Class Codes: G02F 1/133603 with LEDs

Abstract

A backlight device, which uses solid-state light emitting elements capable of emitting lights of three colors, consisting of red, green and blue, can exhibit an enhanced light utilizing efficiency, and can generate light of high uniformity in brightness and chromaticity in a display device which can obtain a display image of high brightness with a rapid response speed. The backlight device includes a reflector which has a light reflection surface, a plurality of light transmitting cylindrical light guide bodies which are mounted on the light reflection surface of the reflector in a uniformly distributed manner, and light emitting diodes capable of emitting lights of at least three colors which are mounted inside each light guide body. By performing color mixing every light guide block, it is possible to obtain a white light of high chromaticity which has a high luminous flux distribution.

Claims

1. A display device comprising:

a liquid crystal display panel which includes electrodes for forming pixels on an inner surface thereof and interposes a liquid crystal layer between a pair of transparent substrates; and

a backlight device which includes;

an optical compensation sheet stacked body which is mounted on a back surface of the liquid crystal display panel;

a light reflection plate which includes a light reflection surface; and

a plurality of solid-state light emitting element units capable of emitting lights of at least three colors mounted on the light reflection surface of the light reflection plate;

wherein each of the plurality of solid-state light emitting element units includes an outer surface of a light-transmitting cylindrical light guide body; and

wherein air is filled inside of the light-transmitting cylindrical light guide body of the solid-state light emitting unit and outside of the light-transmitting cylindrical light guide body so that the air is also provided between the light-transmitting cylindrical light guide bodies of the plurality of solid-state light emitting units.

2. A display device according to claim 1, wherein each of the solid-state light emitting element units includes a red solid-state light emitting element, a green solid-state light emitting element, a blue solid-state light emitting element, and an inner surface of the light-transmitting cylindrical light guide body surrounds and is spaced from the red, green and blue solid-state light elements of the solid-state light emitting element unit by the air;

wherein each of the solid-state light emitting elements is formed of a side-emitter-type solid-state light emitting element capable of emitting light in a sideways direction; and

wherein an optical intensity of the side-emitting solid-state light emitting element assumes a peak value when an irradiation angle θ

of the light becomes θ

=approximately ±

80° and

an angle θ

which halves the optical intensity is ±

20°

.

3. A display device according to claim 2, wherein at least one of the solid-state light emitting elements of the solid-state light emitting element units has a different height from other solid-state light emitting elements of the solid-state light emitting element units.

4. A display device according to claim 2, wherein each light-transmitting cylindrical light guide body includes a light incident surface which is inclined relative to a center axis on an inner wall surface of the light-transmitting cylindrical light guide body.

5. A display device according to claim 2, wherein each light-transmitting cylindrical light guide body integrally includes optical control elements on a cylindrical outer wall surface of the light-transmitting cylindrical light guide body.

6. A display device according to claim 2, wherein the plurality of solid-state light emitting element units are mounted on the light reflection surface of the light reflection plate in a uniformly dispersed manner.

7. A backlight device according to claim 1, wherein each of the solid-state light emitting element units includes a plurality of solid-state light emitting elements capable of emitting light of different colors surrounded by the light transmitting cylindrical light guide body.

8. A display device comprising:

a display panel which performs an image display; and

a backlight device which is mounted on a back surface of the display panel, wherein

the backlight device includes;

a light reflection plate which includes a light reflection surface; and

a plurality of solid-state light emitting element units mounted on the light reflection surface of the light reflection plate;

wherein each of the solid-state light emitting element units includes a red solid-state light emitting element, a green solid-state light emitting element and a blue solid-state light emitting element;

wherein each of the plurality of solid-state light emitting element units includes an outer surface of a light-transmitting cylindrical light guide body surrounding the solid-state light emitting elements therein; and

wherein air is filled inside of the light-transmitting cylindrical light guide body of the solid-state light emitting element unit so that the air is provided between the solid-state light emitting elements and the light transmitting cylindrical light guide body and outside of the light transmitting cylindrical light guide body so that the air is also provided between the light-transmitting cylindrical light guide bodies of the plurality of solid-state light emitting units.

9. A display device according to claim 8, wherein each of the solid-state light emitting elements is formed of a side-emitter-type solid-state light emitting element capable of emitting light in a sideways direction;

wherein an optical intensity of the side-emitting solid-state light emitting assumes a peak value when an irradiation angle θ

of the light becomes θ

=approximately ±

80° and

an angle θ

which halves the optical intensity is ±

20°

.

10. A display device according to claim 9, wherein at least one of the solid-state light emitting elements of the solid-state light emitting element units has different height from other solid-state light-emitting elements.

11. A display device according to claim 8, wherein each light-transmitting cylindrical light guide body includes a light incident surface which is inclined relative to a center axis on an inner wall surface of the light-transmitting cylindrical light guide body.

12. A display device according to claim 8, wherein each light-transmitting cylindrical light guide body includes optical control elements on a cylindrical outer wall surface of the light-transmitting cylindrical light guide body.

13. A display device according to claim 8, wherein the plurality of solid-state light emitting element units are mounted on the light reflection surface of the light reflection plate in a uniformly dispersed manner.

14. A backlight device comprising:

a light reflection plate which includes a light reflection surface; and

a plurality of solid-state light emitting element units mounted on the light reflection surface of the light reflection plate;

wherein each of the plurality of solid-state light emitting element units includes at least two solid-state light emitting elements emitting light of different colors, and an outer surface of a light-transmitting cylindrical light guide body; and

wherein air is filled inside of the light-transmitting cylindrical light guide body of the solid-state light emitting unit so that air is provided between the solid state light emitting elements and the light transmitting cylindrical light guide body and outside of the light-transmitting cylindrical light guide body so that the air is also provided between the light-transmitting cylindrical light guide bodies of the plurality of solid-state light emitting units.

15. A backlight device according to claim 14,

wherein each of the solid-state light emitting element units includes a red solid-state light emitting element, a green solid-state light emitting element and a blue solid-state light emitting element;

wherein each of the solid-state light emitting elements is formed of a side-emitter-type solid-state light emitting element capable of emitting light in a sideways direction;

wherein an optical intensity of the side-emitter solid-state light emitting element assumes a peak value when an irradiation angle θ

of the light becomes θ

=approximately ±

80° and

an angle θ

which halves the optical intensity is ±

20°

.

16. A backlight device according to claim 15, wherein at least one of the solid-state light emitting elements of the solid-state light emitting element unit has different height from other solid-state light emitting elements of the solid-state light-emitting element unit.

17. A backlight device according to claim 14, wherein each light-transmitting cylindrical light guide body includes light incident surface which is inclined relative to a center axis on an inner wall surface of the light-emitting cylindrical light guide body.

18. A backlight device according to claim 14, wherein each light-transmitting cylindrical light guide body integrally includes optical control elements on a cylindrical outer wall surface of the light-transmitting cylindrical light guide body.

19. A backlight device according to claim 14, wherein the plurality of solid-state light emitting element units are mounted on the light reflection surface of the light reflection plate in a uniformly dispersed manner.

20. A backlight device according to claim 14, wherein each of the solid-state light emitting element units includes a plurality of solid-state light emitting elements emitting light of three different colors surrounded by the light transmitting cylindrical body.