Backlit display with improved dynamic range

• US 7,505,028 B2
• Filed: 03/08/2007
• Issued: 03/17/2009
• Est. Priority Date: 11/09/2001
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Daly, Scott J.
• Primary Examiner(s): Awad; Amr
• Assistant Examiner(s): Sherman; Stephen G
• Application Number:
  US11/715,328
• Publication Number:
  US 20070152954A1
• Time in Patent Office: 740 Days
• Field of Search: 345/102, 345/204, 345/87, 345/76, 345/82, 345/690, 349/61, 349/62
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/02 Improving the quality of display appearance
• CPC Class Codes: G09G 2320/0238 Improving the black level
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• 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 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

Abstract

A display is backlit by a source having spatially modulated luminance to attenuate illumination of dark areas of images and increase the dynamic range of the display.

Claims

1. A backlit display, comprising:

a backlight, to output light at a spatially modulatable luminance, including a plurality of light sources that are individually controllable to output light at luminance levels independent of each other;

a light valve to control, per pixel, transmittance of said light from said backlight to create an image for display;

a diffuser provided between said backlight and said light valve, wherein said a diffuser disperses said light from said backlight to increase uniformity of light source luminance; and

a backlight driver to control said light output of said light sources, each of said light sources being controlled based upon luminance for display at pixel regions respectively corresponding to each of said light sources.

2. The backlit display as set forth in claim 1, wherein:

in at least one of a plurality of areas that constitute the image for display,

luminance of said backlight is controlled in accordance with a first feature regarding brightness of said image for display in said at least one area, and

control of said luminance of said backlight is switched to another control, which is different from the control performed in accordance with said first feature, in accordance with a second feature regarding the brightness of said image for display in said at least one area.

3. The backlit display as set forth in claim 1, wherein:

the light sources respectively correspond to areas that constitute part of an image for display,

in accordance with a first feature regarding brightness of said image to be displayed in each of said areas, luminance of said light source corresponding to the each of said areas is controlled, and

if a size of a relatively dark area of said image to be displayed in one of said areas relatively small, said luminance of said light source corresponding to the one of said areas is increased.

4. The backlit display as set forth in claim 1, wherein:

the light sources respectively correspond to areas that constitute part of an image for display,

in accordance with a first feature regarding brightness of said image to be displayed in one of said areas, luminance of said light source corresponding to the one of said areas is controlled, and

if a relatively dark area of said image to be displayed in each of said areas includes a relatively small bright component, said luminance of said light source corresponding to the each of said areas is increased.

5. The backlit display as set forth in claim 1, wherein:

the light sources respectively correspond to areas that constitute part of the image for display,

in accordance with a first feature regarding brightness of said image to be displayed in each of said areas, luminance of said light source corresponding to the each of said areas is controlled, and

if a maximum luminance of said image to be displayed in one of said areas exceeds a threshold, said luminance of said light source corresponding to the one of said areas is increased.

6. A backlit display, comprising:

a backlight, to output light at a luminance that is spatially modulatable in response to pixel display value, including a plurality of light sources that are individually controllable to output light at luminance levels independent of each other;

a light valve to control, per pixel, transmittance of said light from said backlight;

a diffuser, provided between said backlight and said light valve, wherein said diffuser disperses said light from said backlight to increase uniformity of light source luminance; and

a backlight driver to control said light output of said light sources, each of said light sources being controlled based upon luminance for display at pixel regions respectively corresponding to each of said light sources.

7. The backlit display as set forth in claim 6, wherein:

in at least one of a plurality of areas that constitute an image to be displayed,

luminance of said backlight is controlled in accordance with a first feature regarding brightness of said image to be displayed in said at least one area, and

control of said luminance of said backlight is switched to another control, which is different from the control performed in accordance with said first feature, in accordance with a second feature regarding the brightness of said image for display in said at least one area.

8. The backlit display as set forth in claim 6, wherein:

the light sources respectively correspond to areas that constitute part of an image to be displayed,

in accordance with a first feature regarding brightness of said image to be displayed in each of said areas, luminance of said light source corresponding to the each of said areas is controlled, and

if a size of a relatively dark area of said image to be displayed in each of said areas is relatively small, said luminance of said light source corresponding to the each of said areas is increased.

9. The backlit display as set forth in claim 6, wherein:

the light sources respectively correspond to areas that constitute part of an image to be displayed,

in accordance with a first feature regarding brightness of said image to be displayed in each of said areas, luminance of said light source corresponding to the each of said areas is controlled, and

if a relatively dark area of said image to be displayed in each of said areas includes a relatively small bright component, said luminance of said light source corresponding to the each of said areas is increased.

10. The backlit display as set forth in claim 6, wherein:

the light sources respectively correspond to areas that constitute part of an image to be displayed,

in accordance with a first feature regarding brightness of said image to be displayed in each of said areas, luminance of said light source corresponding to the each of said areas is controlled, and

if a maximum luminance of said image to be displayed in each of said areas exceeds a threshold, said luminance of said light source corresponding to the each of said areas is increased.