Light guide plate with transmittance enhancement layer and backlight system using same

• US 20050190576A1
• Filed: 12/23/2004
• Published: 09/01/2005
• Est. Priority Date: 02/27/2004
• Status: Active Grant

• Current Assignee: Hon Hai Precision Industry Co., Ltd.
• Original Assignee: Hon Hai Precision Industry Co., Ltd.
• Inventors: Lin, Jhy-Chain, Leu, Charles, Chen, Ga-Lane, Yu, Tai-Cherng, Lee, Ching-Yen
• Granted Patent: US 7,387,423 B2
• Time in Patent Office: Days
• US Class Current: 362/615
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source

Abstract

A light guide plate (20) in accordance with the present invention includes a transparent plate (200) and a light transmittance enhancement layer (25). The transparent plate includes a light emitting surface (22), and a light incidence surface (21) opposite to the light emitting surface. The light transmittance enhancement layer is provided on the light emitting surface. The light transmittance enhancement layer is made of silicon dioxide or magnesium fluoride. A thickness of the light transmittance enhancement layer is in the range from 58˜69 nanometers. Because of the light transmittance enhancement layer, the light guide plate has enhanced efficiency of utilization of visible light. A backlight system (2) using the light guide plate is also provided.

Claims

1. A light guide plate comprising:

a transparent plate having a light emitting surface and a light incidence surface opposite to the light emitting surface; and

a light transmittance enhancement layer provided on either the light emitting surface or the light incidence surface;

wherein the light transmittance enhancement layer is made of silicon dioxide or magnesium fluoride, and a thickness of the light transmittance enhancement layer is in the range from 58˜

69 nanometers.

2. The light guide plate as claimed in claim 1, wherein the thickness of the light transmittance enhancement layer is approximately 67.22 nanometers.

3. The light guide plate as claimed in claim 1, wherein the thickness of the light transmittance enhancement layer is approximately 59.44 nanometers.

4. The light guide plate as claimed in claim 1, wherein the thickness of the light transmittance enhancement layer is approximately 62.67 nanometers.

5. The light guide plate as claimed in claim 1, further comprising another light transmittance enhancement layer provided on the other of the light emitting surface and the light incidence surface.

6. The light guide plate as claimed in claim 5, wherein a thickness of each of the light transmittance enhancement layers is approximately 59.44 nanometers.

7. The light guide plate as claimed in claim 5, wherein a thickness of one of the light transmittance enhancement layers is approximately 63.65 nanometers, and a thickness of the other light transmittance enhancement layer is approximately 67.52 nanometers.

8. The light guide plate as claimed in claim 5, wherein a thickness of one of the light transmittance enhancement layers is approximately 62.67 nanometers, and a thickness of the other light transmittance enhancement layer is approximately 67.52 nanometers.

9. The light guide plate as claimed in claim 5, wherein a thickness of one of the light transmittance enhancement layers is approximately 59.44 nanometers, and a thickness of the other light transmittance enhancement layer is approximately 67.52 nanometers.

10. The light guide plate as claimed in claim 1, wherein the transparent plate is made of a polymethyl methacrylate resin, and a thickness of the transparent plate is approximately 0.85 millimeters.

11. The light guide plate as claimed in claim 1, wherein the light transmittance enhancement layer is formed on either the light emitting surface or the light incidence surface by electron beam evaporation.

12. A backlight system comprising:

a light guide plate including;

a transparent plate having a light emitting surface and a light incidence surface opposite to the light emitting surface; and

at least one light transmittance enhancement layer provided on at least one of the light emitting surface and the light incidence surface;

wherein said light transmittance enhancement layer is made of silicon dioxide or magnesium fluoride, and a thickness of said light transmittance enhancement layer is in the range from 58˜

69 nanometers; and

a light source located adjacent the light incidence surface of the transparent plate.

13. A method for manufacturing a light guide member, comprising the steps of:

providing a light-transmittable base to form a main body of said light guide member; and

forming a layer made of material for enhancement to light transmittance of said base on at least one side of said base.

14. The method as claimed in claim 13, wherein said layer for enhancement to light transmittance of said base is formed on said at least one side of said base by means of electron beam evaporation during said forming step.

15. The method as claimed in claim 13, wherein said material of said layer is one of silicon dioxide and magnesium fluoride.

16. The method as claimed in claim 13, further comprising the step of forming another layer for enhancement to light transmittance of said base on another side of said base other than said at least one side of said base.

17. The method as claimed in claim 16, wherein thickness of said another layer is different from thickness of said layer.

18. The method as claimed in claim 13, wherein thickness of said layer is ranged between 58 and 69 nanometers.