Image Display Apparatus Black Display-unevenness Correction
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Solution Overview
Problem
Existing technologies for liquid-crystal display apparatuses face challenges in maintaining image contrast when reducing black display-unevenness, as methods to address this issue often result in reduced contrast and increased brightness, leading to suboptimal image quality.
Innovation Solution
The proposed solution involves an image display apparatus that applies black display-unevenness correction processing before local dimming, using a method that adjusts the gradation values and light-emission brightness of light sources to prevent contrast reduction, by determining a black display-unevenness correction value and applying it to the input image data, and then performing extension processing to control the transmittance of the liquid-crystal panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an offset value is added to input image data to reduce black display-unevenness, then black display-unevenness is reduced, but the display brightness of black color is increased and contrast is reduced
Solution Approach 1:
The patent segments the image processing into multiple stages: first adding an offset value to reduce black display-unevenness, then performing local dimming processing by dividing the screen into multiple regions with different light emission brightness levels. This segmentation allows the offset addition to be compensated by regional brightness adjustment, preventing overall contrast loss while maintaining black uniformity.
Solution Approach 2:
The patent applies local dimming by setting different light emission brightness values for different regions of the backlight unit. Regions where black display-unevenness occurs receive adjusted brightness levels, allowing localized compensation for the offset addition without affecting the entire screen's contrast. This local quality adjustment resolves the contradiction between black uniformity and overall image contrast.
2Manufacturing precision
If the light-emission brightness of light sources is increased due to offset value addition, then black display-unevenness is reduced, but the contrast of display image is reduced
Solution Approach 1:
The patent dynamically adjusts the light-emission brightness of different light sources based on the offset value added and the specific display-unevenness characteristics of each region. Rather than uniformly increasing all light sources, the system adaptively controls each region's brightness, allowing black uniformity improvement while preserving local contrast through dynamic regional adjustment.
Solution Approach 2:
The patent changes the light-emission brightness parameter of the backlight unit in a controlled manner, adding offset values to specific regions while adjusting other parameters (light emission intensity per region) to compensate. This parameter change strategy allows black display-unevenness reduction without causing overall contrast degradation, as each region's parameters are optimized independently.
3Manufacturing precision
If black display-unevenness correction is performed by increasing gradation value, then display unevenness is reduced, but the contrast ratio of the display is reduced
Solution Approach 1:
The patent segments the correction process into offset addition for black uniformity and subsequent local dimming for contrast preservation. By dividing the correction into these stages and applying regional brightness adjustments, the system achieves display uniformity without sacrificing the contrast ratio, as each segment addresses a specific aspect of the contradiction.
Solution Approach 2:
The patent introduces local dimming processing as an intermediary mechanism between offset addition and final display output. This intermediary step compensates for the contrast reduction caused by offset addition by adjusting regional brightness levels, thereby maintaining both black uniformity and contrast ratio through the mediating action of selective brightness control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces black display-unevenness while maintaining or enhancing image contrast, thereby improving the overall quality of the displayed image by preventing contrast reduction and minimizing halo phenomena.
Implementation Method 1
The liquid-crystal panel unit has a plurality of liquid-crystal devices. By the control of voltage to be applied to the respective liquid-crystal devices, the transmittance of the respective liquid-crystal devices is controlled.
Data Source
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AI summary
An image display apparatus includes: a display unit; a plurality of light emitting units; and a light-emission controller configured to individually control light-emission brightness of each of the light emitting units, wherein in a case where brightness of light applied to a region of the display unit on which a black region of an input image is displayed is less than or equal to predetermined brightness, transmittance of the display unit is controlled such that transmittance of the region of the display unit corresponding to the black region becomes higher than that in a case in which the brightness is higher than the predetermined brightness.