Local Dimming Backlight Control for Moving-Image Flicker
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional liquid crystal display devices experience flickering due to increased illumination area size with fast-moving objects, leading to reduced display quality and difficulty in achieving true black levels.
Innovation Solution
A display device with a backlight controller that divides the backlight into areas and adjusts the light-emission luminance of adjacent areas based on the motion vector of the image, ensuring the luminance of adjacent areas is higher than the indicated luminance to reduce flickering and suppress raised blacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the illumination area is increased to improve flickering in motion scenes, then flickering is reduced, but display quality deteriorates due to raised blacks and loss of true black level
Solution Approach 1:
The backlight is divided into multiple illumination areas that can be independently controlled. The patent applies local dimming by controlling different areas separately, allowing the illumination area to be dynamically adjusted based on motion detection without affecting the entire backlight, thus reducing flickering while maintaining true black levels in non-illuminated areas
Solution Approach 2:
The illumination area is dynamically adjusted based on motion detection. When motion is detected, the illumination area is expanded to reduce flickering; when still images are displayed, the illumination area is reduced to maintain true black levels. This dynamic adjustment resolves the contradiction between flickering reduction and display quality
2Use of energy by stationary object
If local dimming is applied to control luminance for each divided area, then power consumption is reduced and visibility is improved, but flickering occurs in motion scenes
Solution Approach 1:
The patent incorporates motion detection feedback to adjust the illumination area. The system continuously monitors image motion and dynamically expands or contracts the illumination area accordingly. This feedback mechanism allows the system to maintain low power consumption through local dimming while preventing flickering by expanding the illumination area when motion is detected
3Reliability
If the illumination area is enlarged to cover moving objects, then flickering is improved, but true black level is lost and display quality is lowered
Solution Approach 1:
Different areas of the backlight are controlled with different luminance levels based on local requirements. The patent applies local dimming by setting low luminance in areas where true black is needed and high luminance only in areas where motion objects require illumination. This local quality control allows the system to maintain true black levels while reducing flickering in specific regions
Data Source
AI summary
A display device according to an embodiment is provided with a display panel, a backlight, and a backlight controller which divides the backlight into a plurality of areas, and controls a light-emission luminance of the backlight for each of the plurality of areas on the basis of an image signal. The backlight controller causes the light-emission luminance of the backlight in a first adjacent illumination area which is adjacent, in a direction in which an image included in the image signal moves, to the image to be changed from a luminance indicated by the image signal.