Liquid crystal display device for displaying video data

• US 7,432,897 B2
• Filed: 01/21/2005
• Issued: 10/07/2008
• Est. Priority Date: 03/27/2000
• Status: Expired due to Term

• Current Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Original Assignee: Hitachi, Ltd., Hitachi Micro Software SYST, Hitachi Video And Information System Inc.
• Inventors: Maeda, Takeshi, Kawabe, Kazuyoshi, Kurihara, Hiroshi, Ohashi, Toshiaki, Nishitani, Shigeyuki, Takagi, Tetsuo
• Primary Examiner(s): Hjerpe; Richard
• Assistant Examiner(s): Shapiro; Leonid
• Application Number:
  US11/038,105
• Publication Number:
  US 20050122287A1
• Time in Patent Office: 1,355 Days
• Field of Search: 345 87- 89, 345/204
• US Class Current: 345/87
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2007 Display of intermediate tones
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: H04N 5/66 Transforming electric information into light information scanning details H04N3/00
• CPC Class Codes: H04N 9/69 for modifying the colour signals by gamma correction controlling camera response for colour signals H04N23/83

Abstract

A liquid crystal display device for displaying video data having a detection circuit for detecting a luminance distribution based on video data which is inputted, the luminance distribution being indicative of generation frequency of gradations in each of divided region which includes a plurality of gradations. The display device includes a determination circuit for determining at least one of a plurality of divided regions of higher generation frequency of gradation than that of other divided regions based on the luminance distribution, a correction circuit for correcting the video data so as to make a luminance characteristic of the at least one of the plurality of divided regions of higher generation frequency of gradation more abrupt than a luminance characteristic of the other divided regions, and a liquid crystal display panel for displaying the corrected video data. A width of the divided region is changeable.

Claims

1. A liquid crystal display device for displaying video data, comprising:

a detection circuit for detecting a luminance distribution based on video data which is inputted, the luminance distribution being indicative of generation frequency of gradations in each of divided regions which include a plurality of gradations;

a determination circuit for determining at least one of a plurality of divided regions of higher generation frequency of gradation than that of other divided regions based on the luminance distribution;

a correction circuit for correcting the video data so as to make a luminance characteristic of the at least one of a plurality of divided regions of higher generation frequency of gradation more abrupt than a luminance characteristic of other divided regions; and

a liquid crystal display panel for displaying the corrected video data;

wherein a width of the divided region is changeable.

2. A liquid crystal display device according to claim 1, further comprising:

a setting section for setting the width of the divided region around a middle part of an entire region narrower than the width of the divided region in side parts.

3. A liquid crystal display device according to claim 2, wherein the setting section sets the threshold for the width of the divided region.

4. A liquid crystal display device according to claim 1, wherein the width of the divided region is changed according to the light transmittance of the liquid crystal.

5. A liquid crystal display device according to claim 1, further comprising:

a memory for delaying the video data which is inputted by one frame period;

wherein the detection circuit detects the luminance distribution in one period;

wherein the determination circuit determines the at least one of the plurality of divided regions of higher generation frequency of gradation than that all of other divided regions; and

wherein the correction circuit corrects the video data which is delayed by one frame period.

6. A liquid crystal display device according to claim 1, wherein the correction circuit increases an output gradation number against an input gradation number of the at least one of the plurality of divided regions of higher generation frequency of gradation more than output gradation number against the input gradation number of the other divided regions.

7. A liquid crystal display device according to claim 1, wherein the correction circuit corrects the video data to emphasize contrast of the at least one of the plurality of divided regions of higher generation frequency of gradation more than contrast of the other regions.

8. A liquid crystal display device according to claim 1, further comprising:

a data driver for outputting to the liquid crystal display panel a driving voltage corresponding to the corrected video data; and

a scanning driver for outputting to the liquid crystal display panel a scanning voltage for enabling the display panel to display the corrected video data;

wherein the display panel displays the corrected video data based on the driving voltage and the scanning voltage.

9. A liquid crystal display device according to claim 1, wherein the correction circuit make a luminance characteristic of the divided region of higher generation frequency of gradation more abrupt, make a luminance characteristic of a divided region adjacent the divided region of higher generation frequency of gradation more smooth and keep a luminance characteristic other divided regions.

10. A liquid crystal display device for displaying video data, comprising:

a detection circuit for detecting a luminance distribution based on video data which is inputted, the luminance distribution being indicative of generation frequency of gradations in each of divided regions which include a plurality of gradations;

a determination circuit for determining at least one of a plurality of divided regions of higher generation frequency of gradation than that of other divided regions based on the luminance distribution;

a correction circuit for increasing an output gradation number against an input gradation number of the at least one of the plurality of divided regions of higher generation frequency of gradation more than an output gradation number against an input gradation number of other divided regions, to correct the video data; and

a liquid crystal display panel for displaying the corrected video data;

wherein a width of the divided region is changeable.

11. A liquid crystal display device for displaying video data, comprising:

a detection circuit for detecting a luminance distribution based on video data which is inputted, the luminance distribution being indicative of generation frequency of gradations in each of divided regions which include a plurality of gradations;

a determination circuit for determining at least one of a plurality of divided regions of higher generation frequency of gradation than that of other divided regions based on the luminance distribution;

a correction circuit for correcting the video data so as to emphasize contrast of the at least one of the plurality of divided regions of higher generation frequency of gradation more than contrast of the other divided regions; and

a liquid crystal display panel for displaying the corrected video data;

wherein a width of the divided region is changeable.