Backlight Control for Shutter 3D Crosstalk Reduction
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Solution Overview
Problem
Shutter 3D display technology suffers from crosstalk ghost due to delay in grayscale conversion between left-eye and right-eye images, particularly at high or low grayscales where Over Drive (OD) has an insignificant effect, degrading the visual effect.
Innovation Solution
A method that processes display signals by calculating the average grayscale of display zones in both current and previous frames, adjusting backlight brightness accordingly to reduce crosstalk, and performing Over Drive on specific grayscales to shorten liquid crystal response time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If Over Drive (OD) is used to raise voltage to shorten liquid crystal response time, then the response time is reduced and crosstalk ghost is alleviated, but at high or low grayscales the OD effect becomes insignificant and the display effect degrades
Solution Approach 1:
The patent applies different processing strategies to different grayscale ranges. It identifies display zones with average grayscales in specific ranges (first range for darker zones, second range for brighter zones) and applies selective OD processing only to zones where it will be effective, rather than uniformly applying OD across all pixels. This local differentiation resolves the contradiction by maintaining OD effectiveness where needed while avoiding its limitations at extreme grayscales.
Solution Approach 2:
The patent dynamically adjusts the backlight brightness based on real-time grayscale analysis of display zones. By comparing average grayscales between current and previous frames, the system adaptively controls backlight intensity to compensate for OD limitations at high and low grayscales, making the overall system responsive and effective across the full grayscale range.
2Loss of time
If voltage is increased to shorten liquid crystal response time, then the delay between left and right images is reduced, but the variation in brightness becomes low and the OD effect is insignificant
Solution Approach 1:
The patent introduces backlight control as an intermediary mechanism to achieve the overall goal of reducing crosstalk. Instead of relying solely on voltage increase (OD) which has limited brightness variation effect, the system uses backlight brightness adjustment as a mediating factor to enhance the perceived display effect and compensate for the limitations of OD at extreme grayscales.
Solution Approach 2:
The patent changes the approach from solely modifying voltage parameters (OD) to also modifying backlight brightness parameters. By adjusting the backlight intensity based on grayscale analysis, the system achieves effective crosstalk reduction through parameter changes in the illumination system rather than relying exclusively on liquid crystal voltage changes.
3Reliability
If dynamic backlight adjustment is applied to all display zones, then the visual effect is improved, but the processing complexity increases
Solution Approach 1:
The patent segments the display area into multiple display zones and processes each zone independently based on its average grayscale characteristics. This segmentation allows the system to apply processing only where needed and simplifies the control logic by treating each zone as a separate entity with its own grayscale range classification and processing requirements.
Solution Approach 2:
The patent applies partial processing by selectively enabling OD processing only for display zones where it will be effective (based on grayscale range), rather than applying it universally. This partial action approach reduces unnecessary processing complexity while maintaining visual effect improvement where it matters most.
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
Improves the visual effect by reducing crosstalk between left-eye and right-eye images through dynamic backlight adjustment and Over Drive, effectively addressing the limitations of OD at high and low grayscales.
Implementation Method 1
liquid crystals are driven normally for display, and due to some response time with the deflection of liquid crystal molecules
Implementation Method 2
a left-eye image is seen in a time-division manner by the left eye of a user, and a right-eye image is seen in the time-division manner by the user's right eye
Data Source
AI summary
A method of processing a display signal includes: obtaining the average of grayscales of at least one display zone in a previous frame of image and a current frame of image respectively; comparing in magnitude the average of grayscales of at least one display zone in the current frame of image with the average of grayscales of the corresponding display zone in the previous frame of image; and outputting a backlight control value to increase or reduce the brightness of an illuminating element corresponding to the display zone when the average of grayscales of the at least one display zone in the current frame of image is larger or smaller than the average of grayscales of the corresponding display zone in the previous frame of image.