Liquid crystal display module

• US 7,190,425 B2
• Filed: 12/23/2003
• Issued: 03/13/2007
• Est. Priority Date: 03/13/2003
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Hong, Hyung Ki
• Primary Examiner(s): Dudek; James A.
• Application Number:
  US10/742,915
• Publication Number:
  US 20040179154A1
• Time in Patent Office: 1,176 Days
• Field of Search: 349/65, 349/113, 349/63
• US Class Current: 349/63
• 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 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G02F 1/133616 Front illuminating devices
• CPC Class Codes: G02F 2203/02 reflective

Abstract

A liquid crystal display module according to an embodiment of the present invention includes a lamp to generate light; a light guide panel to convert an incident light from the lamp into a surface light, having a first refractive index; a low refractive index layer fixed on the light guide panel, having a second refractive index, which is relatively lower than the first refractive index, so as to have the light incident to the light guide panel totally reflected on the border area with the light guide panel; and a reflective type of liquid crystal display panel to realize a picture by reflecting the light going out from the low refractive index layer.

Claims

1. A liquid crystal display module, comprising:

a lamp generating light;

a light guide panel that converts an incident light from the lamp into a surface light, said light guide panel having a first refractive index;

a low refractive index layer on the light guide panel having a second refractive index which is lower than the first refractive index, reflecting the light incident to the light guide panel on the border area;

a reflective type of liquid crystal display panel that illuminates a picture by reflecting the light coming from the low refractive index layer; and

a condensing device located between the lamp and the light guide panel, said condensing device controls the angle distribution of the incident light to the light guide panel to reduce the difference between the first refractive index and the second refractive index.

2. The liquid crystal display module according to claim 1, wherein the low refractive index layer is adhered to the light guide panel.

3. The liquid crystal display module according to claim 1, wherein a condition in which light is totally reflected on the border surface of the light guide panel and the low refractive index layer is defined by 90°

−

sin<sup>−

1</sup>(1/the first refractive index)>

sin<sup>−

1</sup>(the second refractive index/the first refractive index).

4. The liquid crystal display module according to claim 1, wherein the first refractive index is 1.7 and the second refractive index is 1.35.

5. The liquid crystal display module according to claim 1, further comprising:

a polarizing sheet on the low refractive index layer;

a phase difference compensation sheet on the polarizing sheet; and

a diffusion sheet on the phase difference compensation sheet.

6. The liquid crystal display module according to claim 5, wherein the polarizing sheet is adhered to the low refractive index layer;

the phase difference compensation sheet is adhered to the polarizing sheet; and

the diffusion sheet is adhered to the phase difference compensation sheet.

7. The liquid crystal display module according to claim 5, wherein the reflective type of liquid crystal display panel includes:

a lower substrate having a reflective electrode, the reflective electrode reflects the light going out from the low refractive layer; and

an upper substrate facing the lower substrate with liquid crystal therebetween.

8. The liquid crystal display module according to claim 5, wherein the reflective type of liquid crystal display panel includes:

an upper substrate having a reflective electrode facing the light guide panel with liquid crystal therebetween, wherein the reflective electrode reflects the light going out from the low refractive layer.

9. The liquid crystal display module according to claim 1, wherein a condition in which light is totally reflected on the border surface of the light guide panel and the low refractive index layer is defined by (90°

−

(condensed angle by condensing device)>

sin<sup>−

1</sup>(the second refractive index/the first refractive index)).

10. The liquid crystal display module according to claim 1, wherein the first refractive index is 1.5 and the second refractive index is 1.35.

11. The liquid crystal display module according to claim 1, further comprising:

a polarizing sheet on the low refractive index layer;

a phase difference compensation sheet on the polarizing sheet; and

a diffusion sheet on the phase difference compensation sheet.

12. The liquid crystal display module according to claim 11, wherein the polarizing sheet is adhered to the low refractive index layer;

the phase difference compensation sheet is adhered to the polarizing sheet; and

the diffusion sheet is adhered to the phase difference compensation sheet.

13. The liquid crystal display module according to claim 11, wherein the reflective type of liquid crystal display panel includes:

a lower substrate having a reflective electrode, the reflective electrode reflecting the light going out from the low refractive layer; and

an upper substrate facing the lower substrate with liquid crystal therebetween.

14. The liquid crystal display module according to claim 11, wherein the reflective type of liquid crystal display panel includes:

an upper substrate having a reflective electrode facing the light guide panel with liquid crystal therebetween, the reflective electrode reflecting the light going out from the low refractive layer.