Regional Backlight Control for VA Display Flicker Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Vertical alignment (VA) type liquid crystal displays experience rapid brightness saturation and color cast issues, leading to image quality degradation, particularly at large viewing angles, and existing solutions cause noticeable flicker due to high and low voltage differences between sub-frames.
Innovation Solution
A display device and driving method that divide the backlight source into regions, allowing independent control of light source brightness, with pixel driving voltages adjusted to minimize brightness differences between sub-frames, using backlight brightness compensation signals to balance light emission and reduce flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If each frame of image is displayed by a front sub-frame and a rear sub-frame with different driving voltages (high voltage and low voltage), then the brightness saturation and color cast issues are improved, but human eyes can obviously feel flicker caused by brightness difference between the two sub-frames
Solution Approach 1:
The backlight source is divided into multiple independent regions, each capable of emitting light of different colors (RGB). Each region can be independently controlled to provide targeted brightness compensation to specific areas of the display, allowing differential brightness adjustment between sub-frames without causing uniform flicker across the entire screen.
Solution Approach 2:
Different regions of the backlight source are assigned different brightness compensation levels based on the driving voltage of corresponding pixel blocks. High voltage sub-frames receive darker backlight compensation while low voltage sub-frames receive brighter compensation, creating local quality variations that balance overall brightness without causing perceptible flicker.
2Illumination intensity
If the difference between high voltage and low voltage is large, then the brightness saturation improves, but human eyes can obviously feel flicker caused by brightness difference between sub-frames
Solution Approach 1:
The system pre-calculates and applies backlight brightness compensation signals before displaying each sub-frame. By anticipating the brightness difference that will result from voltage switching, the system proactively adjusts backlight intensity in each region to counterbalance the expected brightness variation, thereby preventing flicker perception before it occurs.
Solution Approach 2:
The system dynamically changes the brightness parameter of the backlight source in different regions based on the driving voltage applied to pixel blocks. By adjusting the backlight brightness parameter in response to voltage changes, the system maintains relatively constant perceived brightness across sub-frames while preserving the benefits of voltage switching for image quality.
3Illumination intensity
If the backlight source is divided into regions with independent control, then the brightness difference between sub-frames is reduced, but the device complexity increases
Solution Approach 1:
The system merges the control of multiple backlight regions by using a unified compensation algorithm that processes driving voltage information and generates appropriate brightness compensation signals for all regions. This integration approach manages complexity while maintaining the benefits of regional independent control for brightness balancing.
Data Source
AI summary
A display device (300) comprises a display panel (310), a backlight module (320), and a driving circuit (330). The backlight module (320) comprises a backlight source and a partition control unit. The partition control unit is used to partition the backlight source into a plurality of regions, and to independently control the luminance of each colored light source at each region. The driving circuit (330) is used to: acquire an input signal of each given image to be displayed; display said image by means of two sub-frames at the front and the back thereof; determine, according to a driving voltage of pixels corresponding to each region, a magnitude of a backlight brightness compensation signal of each region; and adjust, according to the backlight brightness compensation signal, the luminance of each region.