Display Apparatus Compensation for Waterfall Noise
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Solution Overview
Problem
Liquid crystal display (LCD) panels experience display defects such as waterfall noise due to interference noise from light-source driving signals, leading to luminance differences across the screen.
Innovation Solution
A display apparatus and method that divide the display area into compensation and normal areas, using compensation coefficients and noise compensation data to correct input data for the compensation area, with a delay compensator synchronizing the light-source signal to reduce luminance differences caused by interference noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the light-source driving signal is used to drive the backlight assembly, then the LCD panel can be driven with a frame frequency, but interference noise causes luminance differences and display defects such as waterfall noise
Solution Approach 1:
The display area is divided into a compensation area and a normal area based on the interference pattern caused by the light-source driving signal. The compensation area corresponds to regions where interference noise occurs (e.g., during horizontal retrace periods), while the normal area corresponds to regions without interference. This segmentation allows different compensation strategies to be applied to different regions, effectively addressing the luminance differences caused by interference noise while maintaining frame frequency driving.
Solution Approach 2:
Different compensation coefficients are applied to different areas of the display. The compensation area uses specific compensation coefficients determined based on the interference pattern, while the normal area uses different coefficients. This local quality approach ensures that compensation is tailored to the specific interference conditions in each region, eliminating display defects without affecting the overall frame frequency driving performance.
2Manufacturing precision
If compensation coefficients are applied to correct luminance differences, then display quality improves, but the complexity of the driving circuit increases
Solution Approach 1:
Compensation coefficients are predetermined and stored in lookup tables (LUTs) based on the known interference pattern from the light-source driving signal. The compensation area determiner pre-identifies which areas require compensation based on the synchronization signal and frame frequency. This preliminary action allows the actual compensation to be performed simply by table lookup and coefficient application, rather than requiring complex real-time calculation circuits, thus improving display quality while limiting circuit complexity increase.
3Manufacturing precision
If the display area is divided into compensation and normal areas, then luminance differences are reduced, but the processing time and complexity increase
Solution Approach 1:
The compensation process uses feedback from the synchronization signal and known frame frequency to automatically determine the compensation area. The compensation area determiner uses the relationship between the light-source driving signal and the display refresh to automatically identify which regions need compensation. This feedback mechanism eliminates the need for manual area definition and reduces processing time by using predetermined relationships between the driving signals and display areas.
Data Source
AI summary
A display apparatus includes a display panel which displays an image, a compensation area determiner which divides a display area of the display panel into a compensation area and a normal area, a compensation coefficient determiner which determines a compensation coefficient corresponding to input data of the compensation area, a compensation look up table which stores a noise compensation data which compensates a luminance difference of the compensation area by an interference noise of a light-source driving signal, and a correction data calculator which calculates a correction data corresponding to the input data of the compensation area using the compensation coefficient and the noise compensation data.