IP Library Granted Patent US 8,847,865
Granted Patent B2
US 8,847,865 · App. 13/050,979 · Granted Sep 30, 2014

Liquid crystal display device that suppresses deterioration of image quality

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Quick Facts
Patent No.
US 8,847,865
App. No.
13/050,979
Granted
Sep 30, 2014
Kind
B2
Abstract

A data line driving section ( 6 ) outputs a video signal voltage for each pixel to a data line (DL) for each predetermined period in order. In outputting a video signal voltage for a pixel, the data line driving section ( 6 ) outputs a gradation signal voltage having a voltage corresponding to a gradation value of the pixel as the video signal voltage during a second part of the predetermined period, and outputs a correction gradation signal voltage different from the gradation signal voltage as the video signal voltage during a first part of the predetermined period. A control section ( 4 ) changes a relationship between the correction gradation signal voltage and the gradation signal voltage based on a combination of the gradation value of the pixel and a gradation value of a pixel preceding the pixel.

Claims (33)

1. A liquid crystal display device, comprising:

a plurality of pixels each including a pixel electrode and a thin film transistor having a source connected to the pixel electrode;

a video signal line connected to a drain of the thin film transistor included in each of the plurality of pixels;

output means for outputting, to a gate of the thin film transistor, an on-voltage for turning on the thin film transistor included in corresponding one of the plurality of pixels for each of the plurality of pixels in a predetermined order; and

video signal output means for outputting, to the video signal line, a video signal voltage for the corresponding one of the plurality of pixels for each of the plurality of pixels in the predetermined order,

wherein the video signal output means outputs a reference video signal voltage having a voltage corresponding to a gradation value of the corresponding one of the plurality of pixels as the video signal voltage for the corresponding one of the plurality of pixels during a first part of a period during which the video signal voltage for the corresponding one of the plurality of pixels is output, and outputs a correction video signal voltage having a voltage different from the reference video signal voltage as the video signal voltage for the corresponding one of the plurality of pixels during a second part preceding the first part of the period,

wherein the liquid crystal display device comprising a comparison means for comparing the gradation value of the corresponding one of the plurality of pixels with the gradation value of another one of the plurality of pixels which precedes the corresponding one of the plurality of pixels; and

wherein the control means further comprises correction means for changing a relationship between the reference video signal voltage and the correction video signal voltage based on a result of the comparison means for the corresponding one of the plurality of pixels and based on a combination of the gradation value of the corresponding one of the plurality of pixels and a gradation value of another one of the plurality of pixels which precedes the corresponding one of the plurality of pixels.

2. A liquid crystal display device according to claim 1 , wherein the output means starts to output the on-voltage for turning on the thin film transistor included in the corresponding one of the plurality of pixels when the video signal output means outputs a video signal voltage for the another one of the plurality of pixels which precedes the corresponding one of the plurality of pixels.

3. A liquid crystal display device according to claim 1 , wherein the correction means corrects the gradation value of the corresponding one of the plurality of pixels to obtain a correction gradation value of the corresponding one of the plurality of pixels,

wherein the video signal output means outputs the correction video signal voltage having a voltage corresponding to the correction gradation value of the corresponding one of the plurality of pixels as the video signal voltage for the corresponding one of the plurality of pixels, and

wherein the control means controls a correction amount used when the correction means corrects the gradation value of the corresponding one of the plurality of pixels, based on the gradation value of the corresponding one of the plurality of pixels and the gradation value of the another one of the plurality of pixels which precedes the corresponding one of the plurality of pixels.

4. A liquid crystal display device according to claim 1 , wherein the control means changes the relationship between the reference video signal voltage and the correction video signal voltage for the corresponding one of the plurality of pixels based on a position of the corresponding one of the plurality of pixels and the combination of the gradation value of the corresponding one of the plurality of pixels and the gradation value of the another one of the plurality of pixels which precedes the corresponding one of the plurality of pixels.

5. A liquid crystal display device according to claim 4 , wherein:

the correction means corrects the gradation value of the corresponding one of the plurality of pixels to obtain a correction gradation value of the corresponding one of the plurality of pixels; and further comprising:

storage means for storing a table in which a condition related to the gradation value of the corresponding one of the plurality of pixels, a condition related to the gradation value of the another one of the plurality of pixels which precedes the corresponding one of the plurality of pixels, and correction amount control information are associated with one another, for each of the plurality of pixels,

wherein the video signal output means outputs the correction video signal voltage having a voltage corresponding to the correction gradation value of the corresponding one of the plurality of pixels as the video signal voltage for the corresponding one of the plurality of pixels, and

wherein the control means determines a correction amount used when the correction means corrects the gradation value of the corresponding one of the plurality of pixels, based on the correction amount control information associated with the condition satisfied by the gradation value of the corresponding one of the plurality of pixels and the condition satisfied by the gradation value of the another one of the plurality of pixels which precedes the corresponding one of the plurality of pixels in the table for the corresponding one of the pixels.

6. A liquid crystal display device according to claim 1 , further comprising means for changing the second part of the period during which the video signal output means outputs the video signal voltage for the corresponding one of the plurality of pixels, based on a position of the corresponding one of the plurality of pixels.

7. A liquid crystal display device according to claim 1 , wherein when the gradation value of the corresponding one of the plurality of pixels satisfies a predetermined condition, the video signal output means outputs the correction video signal voltage having a voltage exceeding a voltage corresponding to a maximum gradation as the video signal voltage for the corresponding one of the plurality of pixels.

8. A liquid crystal display device according to claim 7 ,

wherein the correction means corrects the gradation value of the corresponding one of the plurality of pixels based on a correction amount corresponding to a combination of the gradation value of the corresponding one of the plurality of pixels and the gradation value of the another one of the plurality of pixels which precedes the corresponding one of the plurality of pixels to obtain a correction gradation value of the corresponding one of the plurality of pixels,

wherein the video signal output means outputs the correction video signal voltage having a voltage corresponding to the correction gradation value of the corresponding one of the plurality of pixels as the video signal voltage for the corresponding one of the plurality of pixels, and

wherein the correction means obtains a gradation value exhibiting a gradation higher than a maximum gradation as the correction gradation value of the corresponding one of the plurality of pixels when the gradation value of the corresponding one of the plurality of pixels satisfies the predetermined condition.

9. A liquid crystal display device according to claim 1 , wherein when the gradation value of the corresponding one of the plurality of pixels satisfies a predetermined condition, the video signal output means outputs the correction video signal voltage having a voltage different in polarity from a reference video signal voltage for the another one of the plurality of pixels which precedes the corresponding one of the plurality of pixels as the video signal voltage for the corresponding one of the plurality of pixels.

10. A liquid crystal display device according to claim 9 ,

wherein the correction means corrects the gradation value of the corresponding one of the plurality of pixels based on a correction amount corresponding to a combination of the gradation value of the corresponding one of the plurality of pixels and the gradation value of the another one of the plurality of pixels which precedes the corresponding one of the plurality of pixels to obtain a correction gradation value of the corresponding one of the plurality of pixels,

wherein the video signal output means outputs the correction video signal voltage having a voltage corresponding to the correction gradation value of the corresponding one of the plurality of pixels as the video signal voltage for the corresponding one of the plurality of pixels, and

wherein the correction means obtains a correction gradation value different in sign from the gradation value of the another one of the plurality of pixels which precedes the corresponding one of the plurality of pixels when the gradation value of the corresponding one of the plurality of pixels satisfies the predetermined condition.

11. A liquid crystal display device according to claim 1 , further comprising temperature detection means for detecting a temperature,

wherein the control means changes the relationship between the reference video signal voltage and the correction video signal voltage for the corresponding one of the plurality of pixels based on the combination of the gradation value of the corresponding one of the plurality of pixels and the gradation value of the another one of the plurality of pixels which precedes the corresponding one of the plurality of pixels and the temperature detected by the temperature detection means.

12. A liquid crystal display device according to claim 1 , wherein the control means changes the relationship between the reference video signal voltage and the correction video signal voltage for a first pixel of the plurality of pixels based on a combination of a gradation value of the first pixel and a gradation value exhibiting a minimum gradation.

13. A liquid crystal display device according to claim 1 , wherein the video signal output means outputs a video signal voltage for a first pixel of the plurality of pixels for a period longer than a period of a video signal voltage for another one of the plurality of pixels.

Assignments (7)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 10, 2025
From: JAPAN DISPLAY INC
To: MAGNOLIA PURPLE CORPORATION
Reel/Frame 071890/0202 →
NUNC PRO TUNC ASSIGNMENT Recorded Nov 17, 2023
From: PANASONIC LIQUID CRYSTAL DISPLAY CO., LTD.
To: PANASONIC INTELLECTUAL PROPERTY CORPORATION OF AMERICA
Reel/Frame 065615/0327 →
CHANGE OF NAME Recorded Feb 11, 2014
From: JAPAN DISPLAY EAST INC.
To: JAPAN DISPLAY INC.
Reel/Frame 032250/0058 →
CHANGE OF NAME Recorded Feb 10, 2014
From: HITACHI DISPLAYS, LTD.
To: JAPAN DISPLAY EAST INC.
Reel/Frame 032191/0837 →
MERGER Recorded Nov 27, 2012
From: IPS ALPHA SUPPORT CO., LTD.
To: PANASONIC LIQUID CRYSTAL DISPLAY CO., LTD.
Reel/Frame 029358/0841 →
COMPANY SPLIT PLAN TRANSFERRING FIFTY (50) PERCENT SHARE OF PATENTS AND APPLICATIONS Recorded Nov 27, 2012
From: HITACHI DISPLAYS, LTD.
To: IPS ALPHA SUPPORT CO., LTD.
Reel/Frame 029362/0104 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 18, 2011
From: OOISHI, YOSHIHISA; OWA, MISA; MARUYAMA, JUNICHI; TOSHIMA, GOKI
To: HITACHI DISPLAYS, LTD.
Reel/Frame 025978/0249 →