DISPLAY APPARATUS AND DISPLAY METHOD

• US 20060214904A1
• Filed: 03/21/2006
• Published: 09/28/2006
• Est. Priority Date: 03/24/2005
• Status: Active Grant

• Current Assignee: Saturn Licensing LLC (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Hayashi, Masatake, Masuda, Shozo, Kimura, Kazuto
• Granted Patent: US 8,264,447 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• 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 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A display apparatus includes a display unit having a display screen divided into a plurality of regions and controlled using an aperture ratio on a pixel-by-pixel basis, a backlight including a plurality of sets of light sources, each set being disposed so as to correspond to one of the regions, and a control unit for detecting display luminance in each region, computing the emission luminance of each light source on the basis of the detected display luminance while taking into account an effect on the region of the other light sources not corresponding to the region, and computing a correction value for each pixel on the basis of a shift amount between the set emission luminance and an optimal display luminance for one of the regions, and delivering a display driving signal generated on the basis of the correction value to each pixel so as to control the aperture ratio.

Claims

1. A display apparatus comprising:

a display unit having a display screen divided into a plurality of regions, the display unit being controlled using an aperture ratio on a pixel-by-pixel basis;

a backlight for illuminating the back surface of the display unit, the backlight including a plurality of sets of light sources, each set being disposed so as to correspond to one of the regions; and

a control unit for detecting the display luminance in each region of the display unit when an image is displayed on the display unit on the basis of an input image signal, computing the emission luminance of each light source disposed so as to correspond to one of the divided regions on the basis of the detected display luminance while taking into account an effect on the region of the other light sources not corresponding to the region, setting the emission luminance of each light source disposed so as to correspond to one of the divided regions to the computed emission luminance, computing a correction value for each pixel of the display unit on the basis of a shift amount between the set emission luminance and an optimal display luminance value for one of the divided regions of the display screen, and delivering a display driving signal generated on the basis of the computed correction value to each pixel so as to control the aperture ratio of the pixel.

2. The display apparatus according to claim 1, wherein emission luminance is computed for each set of the plurality of light sources disposed so as to correspond to one of the divided regions such that the emission luminance is set to the same value.

3. The display apparatus according to claim 1, wherein the computation of the emission luminance of each light source while taking into account an effect on the region of the other light sources not corresponding to the region is performed by solving simultaneous equations using contribution ratios of the emission luminance of all the light sources to the luminance in the region.

4. The display apparatus according to claim 1, wherein the control unit defines a dynamic range of the display luminance in each divided region of the display unit when the image signal is input as the display state of the display unit in the range from an emission luminance of zero to an emission luminance of substantially the maximum value of the light source corresponding to the divided region so as to detect the display luminance of each divided region of the display unit.

5. A display method for use in a display apparatus, the display apparatus including a display unit having a display screen divided into a plurality of regions, the display unit being controlled using an aperture ratio on a pixel-by-pixel basis, and a backlight for illuminating the back surface of the display unit, the backlight including a plurality of sets of light sources, each set being disposed so as to correspond to one of the regions, the method comprising the steps of:

detecting the display luminance in each region of the display unit when an image is displayed on the display unit on the basis of an input image signal;

computing the emission luminance of each light source disposed so as to correspond to one of the divided regions on the basis of the detected display luminance while taking into account an effect on the region of the other light sources not corresponding to the region;

setting the emission luminance of each light source disposed so as to correspond to one of the divided regions to the computed emission luminance;

computing a correction value for each pixel of the display unit on the basis of a shift amount between the set emission luminance and an optimal display luminance value for one of the divided regions of the display screen; and

delivering a display driving signal generated on the basis of the computed correction value to each pixel so as to control the aperture ratio of the pixel.

6. The display method according to claim 5, wherein computing a correction value for each pixel of the display unit includes correcting the luminance non-uniformity of the display unit.