Control device for liquid crystal display device, liquid crystal display device, method for controlling liquid crystal display device, program, and storage medium for program

• US 9,105,243 B2
• Filed: 03/12/2009
• Issued: 08/11/2015
• Est. Priority Date: 06/27/2008
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Shiomi, Makoto
• Primary Examiner(s): Ghebretinsae, Temesgh
• Assistant Examiner(s): CRAWLEY, KEITH L
• Application Number:
  US12/736,644
• Publication Number:
  US 20110037784A1
• Time in Patent Office: 2,343 Days
• Field of Search: 345/87, 345/89, 345/102, 345/690, 345/694, 345698-699, 348/556
• US Class Current: 1/1
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• 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 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2340/0407 Resolution change, inclusive of the use of different resolutions for different screen areas
• CPC Class Codes: G09G 2340/0442 Handling or displaying different aspect ratios, or changing the aspect ratio
• CPC Class Codes: G09G 2340/0485 Centering horizontally or vertically
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A liquid crystal driving circuit controls operations of display areas in a liquid crystal display panel based on a plural pieces of divided image data which are prepared by dividing image data for a single screen in accordance with the display areas in the liquid crystal display panel. In response to an luminance signal corresponding to an LED resolution generated by an LED resolution signal generating circuit based on image data for a single screen which is not divided, the LED driving circuit controls operations of LEDs provided in a backlight unit. With the configuration of at least one embodiment, according to a liquid crystal display device including a backlight, in a case where display image data for a single screen is divided into a plural pieces of divided image data for a plurality of areas of a display screen and images to be displayed in the plurality of areas are controlled based on the plural pieces of divided image data, display quality in a border area of the plurality of areas can be improved.

Claims

1. A control device for controlling operations of a liquid crystal display device which includes a liquid crystal display panel and a backlight unit having a plurality of light sources arranged in a matrix manner in a backside of the liquid crystal display panel,

said control device comprising:

a liquid crystal control section which controls pixels of the liquid crystal display panel in accordance with plural pieces of divided image data, the plural pieces of divided image data being prepared by dividing image data for a single screen into pieces for respective ones of a plurality of display areas of the liquid crystal display panel;

a backlight control section which controls light-emitting states of respective ones of the plurality of light sources in accordance with undivided image data for a single screen;

a first dividing section which divides inputted image data for a single screen into the plural pieces of divided image data, the inputted image data having a first resolution which is at least a threshold resolution; and

a down-converting section which converts the first resolution of the inputted image data into a second resolution lower than the first resolution, the backlight control section including,

a light source luminance setting section which determines light-emitting luminances of the respective ones of the plurality of light sources in accordance with the undivided image data for the single screen;

a light source driving section which causes the plurality of light sources to emit light in accordance with the respective light-emitting luminances determined by the light source luminance setting section; and

a luminance distribution data generating section which generates luminance distribution data indicative of luminance distribution caused in the liquid crystal display panel due to light emitted by the plurality of light sources, the plurality of light sources emitting the light according to the respective light-emitting luminances determined by the light source luminance setting section, the liquid crystal control section including,

a compensating section which compensates the plural pieces of divided image data in accordance with the luminance distribution data; and

a liquid crystal driving section which drives the pixels of the liquid crystal display panel in accordance with the plural pieces of divided image data compensated by the compensating section,

the light source luminance setting section being configured to determine the light-emitting luminances of the respective ones of the plurality of light sources in accordance with the second resolution of the inputted image data, and

in accordance with the luminance distribution data, the compensating section being configured to compensate the plural pieces of divided image data prepared by the first dividing section.

2. The control device as set forth in claim 1, further comprising:

an image size adjusting section which adjusts an image size of inputted image data for a single screen in a case where an aspect ratio of the inputted image data is different from an aspect ratio of the liquid crystal display panel, the image size adjusting section is configured to add dummy image data to a periphery of the inputted image data so as to adjust the image size of inputted image data, so that the aspect ratio of the inputted image data conforms to the aspect ratio of the liquid crystal display panel, and

the light source luminance setting section is configured to determine the light-emitting luminances of the respective ones of the plurality of light sources in accordance with image data whose image size has been adjusted by the image size adjusting section.

3. The control device as set forth in claim 2, wherein:

the light source luminance setting section is configured to,

divide image data for a single screen into a plurality of blocks which correspond to respective positions in which the plurality of light sources are provided,

determine a light-emitting luminance of each light source in an image display area among the plurality of light sources in accordance with a maximum value among gradation values of pixels included in that one of the plurality of blocks corresponding to the light source, the image display area being an area for displaying an image corresponding to the inputted image data, and

determine a light-emitting luminance of each light source in an image non-display area among the plurality of light sources in accordance with (i) an average luminance level of pixels included in a block of an image display area adjacent to a block corresponding to the light source, the image non-display area being an area in which an image corresponding to the dummy image data is displayed, or (ii) an average luminance level of some of a plurality of small blocks which are adjacent to the image non-display area, the plurality of small blocks being obtained by further dividing the block of the image display area adjacent to the block corresponding to the light source.

4. The control device as set forth in claim 1, further comprising:

an image restoring section which (i) receives the plural pieces of divided image data which have been prepared by dividing the image data for a single screen, and (ii) restores the image data for the single screen by combining the plural pieces of divided image data; and

the down-converting section is configured to convert a resolution of the image data thus restored into a resolution lower than the resolution of the image data thus restored,

the light source luminance setting section is configured to determine the light-emitting luminances of the respective ones of the plurality of light sources in accordance with the image data whose resolution has been lowered by the down-converting section, and

in accordance with the luminance distribution data, the compensating section is configured to compensate the plural pieces of divided image data.

5. The control device as set forth in claim 1, further comprising:

a second dividing section which divides second inputted image data for a single screen into a second plural pieces of divided image data, the second inputted image data having a resolution less than a threshold resolution; and

an upscaling process section which enhances resolutions of the second plural pieces of divided image data so that the resolutions become higher than the resolutions of the second plural pieces of divided image data, the second plural pieces of divided image data having been prepared by the second dividing section,

the light source luminance setting section is configured to determine the light-emitting luminances of the respective ones of the plurality of light sources in accordance with the inputted image data for the single screen, and

in accordance with the luminance distribution data, the compensating section is configured to compensate the second plural pieces of divided image data whose resolutions have been enhanced by the upscaling process section.

6. The control device as set forth in claim 5, wherein:

the second dividing section is configured to generate the second plural pieces of divided image data so that each one of the second plural pieces of divided image data shares a portion with its adjacent one of the second plural pieces of divided image data, so that border areas of that one and its adjacent one of the second plural pieces of divided image data overlap each other,

the upscaling process section includes

a difference operation section which carries out a difference operation process in which a gradation value of a target pixel is calculated by an operation with use of differentiation or difference of gradation values in vicinity to the target pixel, the gradation value of the target pixel being used for extracting an edge of an article pictured in an image,

an averaging process section which carries out an averaging process in which an average value of the gradation values in vicinity to the target pixel is calculated as a gradation value of the target pixel,

a correlation operation section which carries out calculation process for obtaining a correlation value indicative of a correlation between difference image data and averaged image data, the difference image data being produced by subjecting the second plural pieces of divided image data to the difference operation process, and the averaged image data being produced by subjecting the second plural pieces of divided image data to the difference operation process and the averaging process; and

an interpolation process section which carries out an interpolation process on the second plural pieces of divided image data with use of an interpolation method which is selected in accordance with the correlation value.

7. A liquid crystal display device, comprising:

a liquid crystal display panel;

a backlight unit having a plurality of light sources arranged in a matrix manner in a backside of the liquid crystal display panel; and

a control device as set forth in claim 1.

9. A non-transitory computer-readable storage medium storing a program for causing a computer to operate as the liquid crystal control section and the backlight control section of claim 1.

10. The control device as set forth in claim 1, wherein the compensating section includes a plurality of compensating section parts, each of the plurality of compensating section parts is associated with one of the plural pieces of divided image data.

11. The control device as set forth in claim 1, wherein the liquid crystal driving section includes a plurality of liquid crystal driving section parts, each of the plurality of liquid crystal driving section parts is associated with one of the plural pieces of divided image data.

8. A method for controlling a liquid crystal display device which includes a liquid crystal display panel and a backlight unit having a plurality of light sources arranged in a matrix manner in a backside of the liquid crystal display panel,

said method comprising the steps of:

dividing inputted image data for a single screen into plural pieces of divided image data, the dividing divides the inputted image data for the single screen into pieces for respective ones of a plurality of display areas of the liquid crystal display panel, the inputted image data having at least a first resolution;

controlling display states of the plurality of display areas in accordance with the plural pieces of divided image data;

controlling light-emitting states of respective ones of the plurality of light sources in accordance with undivided image data for a single screen, the controlling the light-emitting states including,

determining light-emitting luminances of the respective ones of the plurality of light sources in accordance with the undivided image data for the single screen;

causing the plurality of light sources to emit light in accordance with the respective light-emitting luminances; and

generating luminance distribution data indicative of luminance distribution caused in the liquid crystal display panel due to light emitted by the plurality of light sources, the plurality of light sources emitting the light according to the respective light-emitting luminances,

the controlling the display states including,

compensating the plural pieces of divided image data in accordance with the luminance distribution data; and

driving the pixels of the liquid crystal display panel in accordance with the compensated plural pieces of divided image data; and

converting the first resolution of the inputted image data into a second resolution lower than first resolution of the inputted image data, wherein

the determining light-emitting luminances determines the light-emitting luminances of the respective ones the plurality of light sources in accordance with the second resolution of the inputted image data.