Light valve panel and liquid crystal display using the same

Patent metadata

Field	Value
Publication number	US-10490138-B2
Application number	US-201715604929-A
Country	US
Kind code	B2
Filing date	May 25, 2017
Priority date	May 31, 2016
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

A light valve panel and a liquid crystal display using the same are discussed. The light valve panel according to an aspect includes a liquid crystal layer, a first electrode receiving a light valve data voltage through a light valve data line, and a second electrode facing the first electrode with the liquid crystal layer interposed therebetween, and receiving a common voltage swinging in the same phase in synchronization with the light valve data voltage. The liquid crystal display device according to another aspect includes a display panel, a backlight unit, and a light valve panel.

First claim

What is claimed is:

1. A light valve panel comprising:
a first electrode on a first substrate, receiving a common voltage;
a second electrode on a second substrate, facing the first electrode, and receiving a light valve data voltage; and
a light valve data line directly connected to the second electrode through a contact hole and supplying the light valve data voltage to the second electrode,
wherein the common voltage swings in the same phase in synchronization with the light valve data voltage, and
wherein a modulation voltage is a difference between the common voltage and a reference common voltage, and the modulation voltage has a magnitude not greater than a white margin in a voltage-transmittance (V-T) characteristic curve of a liquid crystal layer.

2. The light valve panel of claim 1 , wherein the liquid crystal layer is disposed between the first and second electrodes.

3. The light valve panel of claim 2 , wherein the light valve data voltage swings between a positive voltage of a voltage level higher than the reference common voltage and a negative voltage of a voltage level lower than the reference common voltage.

4. The light valve panel of claim 3 , wherein the common voltage swings with a predetermined amplitude of the modulation voltage with reference to the reference common voltage.

5. The light valve panel of claim 1 , wherein the second electrode is divided by a plurality of blocks.

6. The light valve panel of claim 1 , wherein the second electrode is formed of a single layer and the light valve data voltage is distributed to the plurality of blocks.

7. A liquid crystal display device comprising:
a display panel including pixels to which an input image is applied;
a backlight unit irradiating light onto the display panel; and
a light valve panel disposed between the display panel and the backlight unit, the light valve panel configured to adjust an amount of the irradiated light from the backlight unit depending on the input image,
wherein the light valve panel includes:
a liquid crystal layer;
a first electrode on a first substrate, receiving a common voltage; and
a second electrode on a second substrate, facing the first electrode with the liquid crystal layer interposed therebetween, and receiving a light valve data voltage through a light valve data line directly connected to the second electrode through a contact hole,
wherein the common voltage swings in the same phase in synchronization with the light valve data voltage, and
wherein a modulation voltage is a difference between the common voltage and a reference common voltage, and the modulation voltage has a magnitude not greater than a white margin in a voltage-transmittance (V-T) characteristic curve of a liquid crystal layer.

8. The liquid crystal display device of claim 7 , wherein the light valve data voltage swings between a positive voltage of a voltage level higher than the reference common voltage and a negative voltage of a voltage level lower than the reference common voltage.

9. The liquid crystal display device of claim 8 , wherein the common voltage swings with a predetermined amplitude of the modulation voltage with reference to the reference common voltage.

10. The light valve panel of claim 7 , wherein the second electrode is divided by a plurality of blocks.

11. The liquid crystal display device of claim 10 , wherein the second electrode is made of a single layer and the light valve data voltage is distributed to the plurality of blocks.

12. A light valve panel having first and second substrates, configured to control an amount of incident light based on a luminance distribution of an input image, comprising:
a first electrode on the first substrate, receiving a common voltage;
a second electrode on the second substrate, facing the first electrode, and receiving a light valve data voltage; and
a light valve data line directly connected to the second electrode through a contact hole and supplying the light valve data voltage to the second electrode,
wherein the light valve panel controls the amount of the incident light by compensating a voltage drop of the light valve data voltage at the second electrode through swinging the common voltage synchronized with the light valve data voltage to have the same phase with each other, and
wherein a modulation voltage is a difference between the common voltage and a reference common voltage, and the modulation voltage has a magnitude not greater than a white margin in a voltage-transmittance (V-T) characteristic curve of a liquid crystal layer.

13. The light valve panel of claim 12 , wherein the light valve data line is connected to the second electrode through a plurality of contact holes, wherein the plurality of contact holes are spaced apart from each other in the same distance at a center portion of the second electrode in a horizontal direction.

14. The light valve panel of claim 12 , wherein the light valve data voltage swings between a positive voltage of a voltage level higher than the reference common voltage and a negative voltage of a voltage level lower than the reference common voltage.

15. The light valve panel of claim 14 , wherein the common voltage swings with a predetermined amplitude of the modulation voltage with reference to the reference common voltage.

16. The light valve panel of claim 12 , wherein the second electrode is divided by a plurality of blocks.

17. The light valve panel of claim 16 , wherein the light valve data voltage is distributed to the plurality of blocks of the second electrode.

Assignees

• Lg Display Co Ltd

Inventors

• Nam Sangjin
• Yoo Ooksang
• Kim Kyujin
• Yoo Seungjin

Classifications

• G09G2320/0626

  for control of overall brightness · CPC title

• G09G2320/0238

  Improving the black level · CPC title

• G02F1/1347

  Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells · CPC title

• G09G2320/0242

  Compensation of deficiencies in the appearance of colours · CPC title

• G09G3/3406 Primary

  Control of illumination source (illumination devices structurally associated with liquid crystal cells G02F1/1336) · CPC title