DISPLAY APPARATUS

• US 20170336676A1
• Filed: 05/15/2017
• Published: 11/23/2017
• Est. Priority Date: 05/17/2016
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: Harada, Tsutomu, Sako, Kazuhiko, Kurokawa, Tae
• Granted Patent: US 10,139,675 B2
• Time in Patent Office: Days
• CPC Class Codes: G02F 1/133602 Direct backlight
• CPC Class Codes: G09G 2310/0232 Special driving of display border areas
• CPC Class Codes: G09G 2320/0238 Improving the black level
• 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 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• 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 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127
• CPC Class Codes: G09G 3/3666 with the matrix divided into sections

Abstract

According to an aspect, a display apparatus includes: an image display panel that displays an image thereon; a planar light source that includes a plurality of light sources and irradiates a plurality of divided areas of the image display panel with light from the back side of the image display panel; and a signal processor that drives the light sources individually based on input signals of the image to control brightness of the individual divided areas. The signal processor performs image display on the image display panel using output signals obtained by lowering brightness of a dark region in the image represented by the input signals.

Claims

1. A display apparatus comprising:

an image display panel that displays an image thereon;

a planar light source that includes a plurality of light sources and irradiates a plurality of divided areas of the image display panel with light from the back side of the image display panel; and

a signal processor that drives the light sources individually based on input signals of the image to control brightness of the individual divided areas,

wherein the signal processor performs image display on the image display panel using output signals obtained by lowering brightness of a dark region in the image represented by the input signals.

2. The display apparatus according to claim 1,

wherein the signal processor performs a histogram analysis on the input signals and lowers the brightness of the dark region in accordance with characteristics corresponding to a result of the histogram analysis to obtain the output signals.

3. The display apparatus according to claim 2,

wherein, in the histogram analysis, the signal processor analyzes the number of pixels at each level of brightness indicated by the input signals of the image.

4. The display apparatus according to claim 2,

wherein, in accordance with the result of the histogram analysis, the signal processor performs image processing such that:

for a region in which brightness of an original image is equal to or higher than a certain brightness threshold, brightness of the original image is maintained; and

for a region in which brightness of the original image is lower than the certain brightness threshold, decrease in brightness after the image processing relative to decrease in brightness of the original image becomes gradually larger as the brightness of the original image decreases.

5. The display apparatus according to claim 2,

wherein the signal processor obtains the output signals by lowering brightness of the dark region by performing bit-length extension processing using a bit conversion table corresponding to the result of the histogram analysis.

6. The display apparatus according to claim 1,

wherein the signal processor lowers brightness of the dark region by:

performing bit-length extension processing on the input signals, and

performing image processing on the input signals subjected to the bit-length extension processing, using corrected expansion coefficients of respective pixels arranged in the image display panel, the corrected expansion coefficients being obtained by correcting expansion coefficients of the respective pixels using correction coefficients corresponding to the expansion coefficients.

7. A display apparatus comprising:

an image display panel that displays an image thereon;

a planar light source that includes a plurality of light sources and irradiates a plurality of divided areas of the image display panel with light from the back side of the image display panel; and

a signal processor that controls brightness of the divided areas based on input signals of the image,

wherein the signal processor performs image display on the image display panel using output signals obtained by lowering brightness of a dark region in the image represented by the input signals.

8. The display apparatus according to claim 7,

wherein the signal processor performs a histogram analysis on the input signals and lowers the brightness of the dark region in accordance with characteristics corresponding to a result of the histogram analysis to obtain the output signals.

9. The display apparatus according to claim 8,

wherein, in the histogram analysis, the signal processor analyzes the number of pixels at each level of brightness indicated by the input signals of the image.

10. The display apparatus according to claim 8,

wherein, in accordance with the result of the histogram analysis, the signal processor performs image processing such that:

for a region in which brightness of an original image is equal to or higher than a certain brightness threshold, brightness of the original image is maintained; and

for a region in which brightness of the original image is lower than the certain brightness threshold, decrease in brightness after the image processing relative to decrease in brightness of the original image becomes gradually larger as the brightness of the original image decreases.

11. The display apparatus according to claim 8,

wherein the signal processor obtains the output signals by lowering brightness of the dark region by performing bit-length extension processing using a bit conversion table corresponding to the result of the histogram analysis.

12. The display apparatus according to claim 7,

wherein the signal processor lowers brightness of the dark region by:

performing bit-length extension processing on the input signals, and

performing image processing on the input signals subjected to the bit-length extension processing, using corrected expansion coefficients of respective pixels arranged in the image display panel, the corrected expansion coefficients being obtained by correcting expansion coefficients of the respective pixels using correction coefficients corresponding to the expansion coefficients.