Display Device Pixel Group Voltage Shifting for Flicker Reduction
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Solution Overview
Problem
In display devices using the pseudo-RGBW scheme, where half of the B-pixels are replaced by W-pixels, manufacturing irregularities lead to differences in optimal common voltage between pixels of different sizes due to variations in storage capacitance and parasitic capacitance, causing issues like flickering and screen burn-in, which existing methods fail to correct effectively without increasing electric power consumption.
Innovation Solution
The solution involves adjusting the common voltage to an optimal value for one pixel group and correcting the difference in optimal common voltage between pixel groups by shifting the entire grayscale voltage of the other group in a vertical direction, allowing for the same common voltage to be applied across all pixels while accounting for manufacturing irregularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pixels are changed in pitch (size) to accommodate W-pixels in pseudo-RGBW scheme, then transmittance and luminance are enhanced, but optimal common voltage differs between pixels of different pitches due to manufacturing irregularities
Solution Approach 1:
The patent applies different grayscale voltage characteristics to different pixel groups based on their pitch sizes. Specifically, pixels with a first pitch (e.g., R and G pixels) are driven with a first grayscale voltage characteristic, while pixels with a second pitch (e.g., B and W pixels) are driven with a second grayscale voltage characteristic. This local differentiation allows each pixel group to operate at its optimal voltage level despite manufacturing variations, resolving the contradiction between enhanced luminance and voltage consistency.
2Reliability
If common voltage is adjusted to optimal value for one pixel group, then performance of that group is optimized, but difference in optimal common voltage between pixel groups causes flickering and screen burn-in
Solution Approach 1:
The patent segments the pixel array into multiple pixel groups based on pitch size (e.g., first pixel group with R and G pixels, second pixel group with B and W pixels). Each segment is then driven with its own optimized grayscale voltage characteristic. This segmentation allows the system to apply different voltage adjustments to different groups, preventing flickering and screen burn-in that would occur with a uniform common voltage approach.
Solution Approach 2:
The patent changes the grayscale voltage parameter differently for different pixel groups. Specifically, it applies a first grayscale voltage characteristic to pixels with a first pitch and a second grayscale voltage characteristic to pixels with a second pitch. This parameter differentiation compensates for the differences in optimal common voltage caused by manufacturing irregularities, thereby eliminating display instability issues while maintaining overall display reliability.
Data Source
AI summary
A display device includes a first pixel group and a second pixel group. A central value of positive-side and negative-side grayscale voltages of the first pixel group is set to be a fixed value. A common voltage is adjusted to its optimal value with respect to the first pixel group. A difference between the common voltage adjusted to the optimal value with respect to the first pixel group and an optimal common voltage of the second pixel group is corrected by shifting entire positive-side and negative-side grayscale voltages of the second pixel group in a vertical direction.