LIQUID CRYSTAL DISPLAY DEVICE

• US 20120176563A1
• Filed: 12/22/2011
• Published: 07/12/2012
• Est. Priority Date: 01/07/2011
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: ADACHI, Masaya, Itou, Osamu, Nishizawa, Shigeki
• Granted Patent: US 8,610,865 B2
• Time in Patent Office: Days
• US Class Current: 349/62
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/134372 for fringe field switching [FFS] where the common electrode is not patterned

Abstract

The TFT substrate includes a pixel electrode and a common electrode laminated one on top of another via an insulating layer, one of the pixel electrode and the common electrode provided farther from the liquid crystal layer being formed into a plane shape, and another of the pixel electrode and the common electrode provided closer to the liquid crystal layer having slits formed therein, each of the plurality of slits having a closed end portion. The liquid crystal display panel further includes a reflection portion for reflecting light, the reflection portion being formed at a surface of the liquid crystal display panel on the illumination device side in a portion which overlaps, in plan view, the end portion of the each of the slits in the long-side direction and a vicinity thereof, and a part of an inner region of the each of the slits.

Claims

1. A liquid crystal display device, comprising:

a liquid crystal display panel comprising;

a TFT substrate including a thin film transistor;

a counter substrate arranged opposed to the TFT substrate; and

a liquid crystal layer sandwiched between the TFT substrate and the counter substrate,

the TFT substrate including a pixel electrode and a common electrode laminated one on top of another via an insulating layer,

one of the pixel electrode and the common electrode provided farther from the liquid crystal layer being formed into a plane shape, and another of the pixel electrode and the common electrode provided closer to the liquid crystal layer having a plurality of slits formed therein,

each of the plurality of slits having an end portion in a long-side direction, which is closed; and

illumination means serving as a light source for the liquid crystal display panel,

wherein the liquid crystal display panel further comprises reflection means for reflecting light, the reflection means being formed at a surface of the liquid crystal display panel on the illumination means side in a portion which overlaps, in plan view, the end portion of the each of the plurality of slits in the long-side direction and a vicinity thereof, and a part of an inner region of the each of the plurality of slits.

2. The liquid crystal display device according to claim 1, wherein:

the reflection means comprises a metal layer; and

the reflection means is formed separately from another metal layer different from the metal layer forming the reflection means.

3. The liquid crystal display device according to claim 1, wherein the reflection means is formed so that a distance from the end portion of the each of the plurality of slits in the long-side direction is within a range of larger than 0 μ

m and 4 μ

m or smaller.

4. The liquid crystal display device according to claim 1, wherein the reflection means is formed so that a distance from the end portion of the each of the plurality of slits in the long-side direction is within a range of 2 μ

m or larger and 4 μ

m or smaller.

5. The liquid crystal display device according to claim 1, wherein:

the end portion of the each of the plurality of slits in the long-side direction has a shape in which one side of a pair of sides forming a width of the each of the plurality of slits in a short-side direction is inclined toward another side of the pair of sides so that the end portion is tapered; and

the reflection means is formed from the another side different from the inclined side of the pair of sides up to substantially a center position of the width of the each of the plurality of slits in the short-side direction.

6. The liquid crystal display device according to claim 5, wherein:

the reflection means comprises;

a base portion formed into a plane shape; and

a plurality of protruding portions formed so as to protrude from the base portion; and

each of the plurality of protruding portions is formed so as to overlap the end portion of the each of the plurality of slits from the another side different from the inclined side of the pair of sides forming the end portion of the each of the plurality of slits up to substantially the center position of the width of the each of the plurality of slits in the short-side direction.

7. The liquid crystal display device according to claim 1, wherein:

the each of the plurality of slits is bent in a vicinity of the end portion in the long-side direction and has a tapered shape;

the reflection means comprises;

a base portion formed into a plane shape; and

a plurality of protruding portions formed so as to protrude from the base portion; and

each of the plurality of protruding portions is formed into a wedge shape in which a top end thereof is positioned at substantially a center of a width of the each of the plurality of slits in a short-side direction.

8. The liquid crystal display device according to claim 1, wherein:

the each of the plurality of slits is bent; and

the reflection means is formed so as to overlap a bent portion of the each of the plurality of slits.

9. The liquid crystal display device according to claim 1, wherein the liquid crystal display panel further comprises:

a front-surface polarizing plate arranged on a display surface side of the liquid crystal display panel;

a rear-surface polarizing plate arranged on a surface of the liquid crystal display panel on the illumination means side; and

a reflection-type polarizing plate arranged on a surface of the rear-surface polarizing plate on the illumination means side, the reflection-type polarizing plate being configured to transmit linearly polarized light in a transmission axis direction of the rear-surface polarizing plate and reflect linearly polarized light in an absorption axis direction of the rear-surface polarizing plate.

10. The liquid crystal display device according to claim 1, wherein the liquid crystal display panel further comprises an underlayer having a lamination structure in which layers having different refractive indexes are laminated, the underlayer being formed between a transparent insulating substrate forming the liquid crystal display panel and the reflection means.

11. The liquid crystal display device according to claim 1, wherein the reflection means is formed in the same layer as a layer in which a scanning signal line of the liquid crystal display panel is formed.

12. The liquid crystal display device according to claim 1, wherein the reflection means is formed in the same layer as a layer in which a source electrode of the liquid crystal display panel is formed, and is electrically connected to the pixel electrode.

13. The liquid crystal display device according to claim 2, wherein the reflection means is formed in a layer different from the another metal layer.

14. The liquid crystal display device according to claim 1, wherein the reflection means is further formed at a portion overlapping a video signal line of the liquid crystal display panel.