Surface illuminator and liquid crystal display having the same

• US 20060220040A1
• Filed: 02/28/2006
• Published: 10/05/2006
• Est. Priority Date: 02/28/2005
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Suzuki, Toshihiro
• Granted Patent: US 7,448,785 B2
• Time in Patent Office: Days
• US Class Current: 257/89
• CPC Class Codes: G02B 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources

Abstract

The invention relates to a surface illuminator and a liquid crystal display having the same and provides a surface illuminator capable of achieving high display quality by employing an array of discrete light sources and a liquid crystal display having the same. A reflective surface for reflecting light in a light guide region of a light guide extends from an end of a light entrance surface through which light enters the light guide region. An LED light source serving as an array of discrete light sources is constituted by a red emission LED, a green emission LED, a blue emission LED, and another green emission LED provided alternately and discretely along the light entrance surface. A red LED serving as an end light source provided at the end of the LED light source on the side of an end of a reflective surface is disposed such that about one half of an emitting region of the same is obscured by the reflective surface to prevent about one half of the quantity of light emitted from entering the light guide region.

Claims

1. A surface illuminator comprising:

a light exit region which spreads in the form of a plane and from which light exits;

a light guide region for guiding light to the light exit region;

a light entrance surface through which light enters the light guide region;

a reflective surface extending from an end of the light entrance surface and reflecting light in the light guide region;

an array of discrete light sources which are plural types of light sources emitting beams of light having different emission wavelength spectra and which are alternately and discretely provided along the light entrance surface; and

an end light source for emitting light having a quantity of light smaller than that of the other light sources of the same type in the array of discrete light sources toward the light guide region.

2. A surface illuminator according to claim 1, wherein a part of light emitted by the end light surface is blocked and prevented from entering the light guide region.

3. A surface illuminator according to claim 2, wherein the end light source is provided such that a part of light emitted by the same is blocked by the reflective surface and prevented from entering the light guide region.

4. A surface illuminator according to claim 2, wherein substantially one half of the quantity of light emitted by the end light surface enters the light guide region.

5. A surface illuminator according to claim 1, wherein the end light source emits a quantity of light which is substantially one half of light from the other light sources of the same type.

6. A surface illuminator according to claim 1, wherein the array of discrete light sources includes a light source set comprising three light sources, i.e., a light source in a color X, a light source in a color Y, and a light source in a color Z provided in series at a side end of the reflective surface and wherein the end light source is the light source among the light source set which is closest to the side end of the reflective surface.

7. A surface illuminator according to claim 1, wherein the array of discrete light sources includes a light source set comprising four light sources, i.e., a light source in a color X, a light source in a color Y, a light source in a color Z, and another light source in the color Y provided in series in the order listed staring at a side end of the reflective surface and wherein the end light source is the light source in the color X among the light source set.

9. A surface illuminator according to claim 6, wherein:

the color X is blue or red;

the color Y is green; and

the color Z is red or blue.

10. A surface illuminator according to claim 1, wherein the light source is an LED.

11. A surface illuminator according to claim 1, wherein the light guide region is a light guide constituted by a transparent member.

12. A surface illuminator according to claim 1, wherein the light guide region is a layer of air.

13. A surface illuminator according to claim 1, wherein a couple of the light entrance surfaces are provided opposite to each other.

14. A surface illuminator according to claim 1, wherein the reflective surface is substantially a mirror surface.

15. A surface illuminator according to claim 1, wherein a reflective sheet is provided on a backside of the reflective surface.

16. A surface illuminator according to claim 1, wherein the reflective surface is provided at both ends of the light entrance surface.

17. A liquid crystal display comprising a liquid crystal display panel provided by sealing a liquid crystal between a pair of substrates and a surface illuminator for illuminating the liquid crystal display panel, wherein the surface illuminator is a surface illuminator according to claim 1.

18. A liquid crystal display according to claim 17, wherein the surface illuminator serves as a backlight unit.

8. A surface illuminator comprising:

a light exit region which spreads in the form of a plane and from which light exits;

a light guide region for guiding light to the light exit region;

a light entrance surface through which light enters the light guide region;

a reflective surface extending from an end of the light entrance surface and reflecting light in the light guide region; and

an array of discrete light sources including a light source set comprising a light source in a color X, a light source in a color Y, a light source in a color Z, and another light source in the color Y provided in series in the order listed starting at a side end of the reflective surface.

19. A liquid crystal display comprising a liquid crystal display panel provided by sealing a liquid crystal between a pair of substrates and a surface illuminator for illuminating the liquid crystal display panel, wherein the surface illuminator is a surface illuminator according to claim 8.