Backlight Luminance Correction for LCD Halo Reduction
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Solution Overview
Problem
Conventional image display devices using backlights with light-emitting regions in a matrix configuration experience a halo phenomenon due to light leakage between adjacent regions, which becomes noticeable as luminance differences increase.
Innovation Solution
An image display method that generates luminance data based on the maximum gradation value of input image pixels, corrects luminance values to be within a predetermined range relative to neighboring regions, and adjusts luminance and gradation settings to suppress the halo phenomenon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If local dimming is implemented with high luminance differences between adjacent light-emitting regions, then image contrast is improved, but halo phenomenon becomes noticeable
Solution Approach 1:
The patent applies preliminary anti-action by preemptively adjusting the luminance values before displaying the image. The correction unit modifies the luminance data in advance to prevent the halo phenomenon from occurring, rather than trying to eliminate it after it appears. This is achieved by detecting potential halo-prone areas and adjusting their luminance values beforehand.
Solution Approach 2:
The patent changes the luminance parameter values dynamically based on the detected image content and backlight structure. The correction unit adjusts the luminance values of specific light-emitting regions by comparing them with their neighboring regions and applying correction when the difference exceeds a threshold, thereby optimizing the balance between contrast and halo suppression.
2Object-affected harmful factors
If luminance correction is applied to suppress halo phenomenon, then halo noticeability is reduced, but luminance data processing complexity increases
Solution Approach 1:
The patent applies local quality by performing luminance correction only on specific light-emitting regions where the halo phenomenon is detected or predicted to occur, rather than uniformly processing all regions. The correction unit compares each region's luminance with its neighbors and applies correction selectively based on a threshold, thereby reducing unnecessary processing.
Solution Approach 2:
The patent replaces complex physical or mechanical halo suppression methods with a computational approach. Instead of using physical barriers or complex optical structures to prevent light leakage, the system uses image processing algorithms to detect and correct luminance values digitally, simplifying the overall system while maintaining effectiveness.
Data Source
AI summary
An image display method includes generating luminance data, correcting the luminance data, generating gradation setting data, and controlling a backlight to operate based on the luminance setting data and a liquid crystal panel to operate based on the gradation setting data. The luminance data indicates a luminance value for each light-emitting region of the backlight and is generated based on a maximum gradation value among gradation values of image pixels of an input image that correspond to the light-emitting region. The luminance data is corrected such that, with respect to each light-emitting region, the luminance value is within a predetermined range below a maximum value among the luminance values of neighboring light-emitting regions, and luminance setting data is generated therefrom. The gradation setting data sets a gradation value of each pixel of the liquid crystal panel, and generated based on the input image and the luminance setting data.