BACKLIGHT UNIT AND CONTROL METHOD FOR THE SAME

• US 20110025725A1
• Filed: 07/15/2010
• Published: 02/03/2011
• Est. Priority Date: 07/15/2009
• Status: Abandoned Application

• Current Assignee: Entropic Communications Incorporated (Maxlinear Incorporated)
• Original Assignee: Entropic Communications Incorporated (Maxlinear Incorporated)
• Inventors: Hulze, Hendrikus Groot
• Application Number:
  US12/836,812
• Publication Number:
  US 20110025725A1
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2320/062 Adjustment of illumination source parameters
• 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 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

A backlight unit for a display device and a control method for the same is presented. The backlight unit comprises: a plurality of light source units arranged in a matrix form; a light source controller adapted to supply a control signal for controlling a brightness of the light source units; and a plurality of light source drive units adapted to supply different driving signals to different light source units based on the control signal. The control signal is generated based on optical crosstalk between neighboring light source units.

Claims

1. A backlight unit for a display device comprising:

a plurality of light source units arranged in a matrix form;

a light source controller adapted to supply a control signal for controlling a brightness of the light source units; and

a plurality of light source drive units adapted to supply different driving signals to different light source units based on the control signal,

wherein the control signal is generated based on optical crosstalk between neighboring light source units;

characterized in that said control signal is determined in at least two steps, wherein in one step the control signal of one or more neighboring light source units is modified using an error spread function to compensate for local light shortage and/or local light surplus of the light source units.

2. The backlight unit of claim 1, wherein the control signal is determined by a histogram-based video-data analysis, using a higher spatial resolution than the light source units resolution.

3. The backlight of claim 2, wherein the control signal is determined using spatial high pass filtering so as to compensate for a low pass characteristic of optical crosstalk between neighboring light source units.

4. The backlight unit of claim 3, wherein the control signal is generated according to a requested backlight lighting profile for the backlight, the requested backlight profile representing a target brightness level for each of the plurality of light sources.

5. The backlight unit of claim 4, wherein the control signal is generated according to a comparison of the brightness of one or more subsegments of the light source units with the backlight lighting profile.

6. The backlight unit of claim 5, wherein the control signal is generated according to a comparison of the brightness of one or more subsegments of different light source units using an error spread function.

7. The backlight unit of claim 6, further comprising a driver feedback unit adapted to calculate the brightness of the backlight at the position of the subsegments and to provide a feedback signal to the controller based on calculated brightness,

and wherein the controller is adapted to modify the control signal based on the feedback signal.

8. The backlight unit of claim 7, wherein the feedback signal indicates that the calculated brightness of a first light source unit is not within a predetermined range of a target value, the control signal is modified to change the brightness of one or more neighboring light source units of the first light source unit.

9. A display device comprising:

a backlight unit for a display device comprising;

a plurality of light source units arranged in a matrix form;

a light source controller adapted to supply a control signal for controlling a brightness of the light source units; and

a plurality of light source drive units adapted to supply different driving signals to different light source units based on the control signal,

wherein the control signal is generated based on optical crosstalk between neighboring light source units;

characterized in that said control signal is determined in at least two steps, wherein in one step the control signal of one or more neighboring light source units is modified using an error spread function to compensate for local light shortage or local light surplus of the light source units.

10. A control method for a backlight unit comprising a plurality of light source units arranged in a matrix form, wherein the method comprises the steps of:

generating a control signal for controlling a brightness of the light source units; and

supplying different driving signals to different light source units based on the control signal,

wherein the control signal is generated based on optical crosstalk between neighboring light source units;

characterized in that said control signal is determined in at least two steps, wherein in one step the control signal of one or more neighboring light source units is modified using an error spread function to compensate for local light shortage and/or local light surplus of the light source units.

11. The method of claim 10, wherein the steps of generating the control signal comprises using a histogram-based video-data analysis, using a higher spatial resolution than the light source units resolution.

12. The method of claim 11, wherein the step of generating the control signal comprises using spatial high pass filtering so as to compensate for a low pass characteristic of optical crosstalk between neighboring light source units.

13. The method of claim 12, further comprising:

calculating the backlight brightness at the position of the subsegments;

providing a feedback signal to the controller (125) based on the calculated brightness; and

modifying the control signal based on the feedback signal.

14. A computer program product, comprising a computer usable medium having a computer readable program code embodied therein, said computer readable program code adapted to be executed to implement a method for controlling a backlight unit comprising a plurality of light source units arranged in a matrix form, said method comprising:

generating a control signal for controlling a brightness of the light source units; and

supplying different driving signals to different light source units based on the control signal,

wherein the control signal is generated based on optical crosstalk between neighboring light source units;

characterized in that said control signal is determined in at least two steps, wherein in one step the control signal of one or more neighboring light source units is modified using an error spread function to compensate for local light shortage and/or local light surplus of the light source units.

15. A computer program product as claimed in claim 14 wherein the method further comprises:

calculating the backlight brightness at the position of the subsegments;

providing a feedback signal to the controller based on the calculated brightness; and

modifying the control signal based on the feedback signal.