LCD Panel Voltage Control for Last Gate Line Whitening
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Solution Overview
Problem
The CS-type SPVA mode LCD exhibits a whitening phenomenon where pixels connected to the last gate line emit brighter light than others, due to uncontrolled main and sub pixel voltages after the last horizontal scanning period.
Innovation Solution
Incorporating a voltage controller for the penultimate gate line to adjust the first pixel voltage and decrease the second pixel voltage, and a dummy voltage controller for the last gate line to further adjust these voltages, along with a black matrix to partially cover the effective display area of the last gate line, ensuring uniform brightness across all pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a voltage controller is added for the penultimate gate line to control pixel voltages, then display uniformity is improved, but device complexity increases
Solution Approach 1:
A voltage controller is added to the penultimate gate line to preliminarily adjust the first and second pixel voltages before the final display phase. This preliminary voltage adjustment ensures that pixels on the last gate line, which would otherwise exhibit whitening phenomenon, receive pre-controlled voltages that maintain display uniformity across the entire display apparatus.
2Manufacturing precision
If a dummy voltage controller is added for the last gate line to adjust pixel voltages, then display uniformity is improved, but device complexity increases
Solution Approach 1:
A dummy voltage controller is introduced as an intermediary component specifically for the last gate line. This dummy controller acts as a mediator to adjust the pixel voltages on the final gate line, compensating for the whitening phenomenon that occurs due to uncontrolled voltage levels in the absence of a subsequent horizontal scanning period.
3Manufacturing precision
If a black matrix is used to partially cover the effective display area of the last gate line, then brightness uniformity is improved, but the display area is reduced
Solution Approach 1:
A black matrix is strategically positioned to partially cover the effective display area of the last gate line. This black matrix converts the harmful whitening phenomenon into a controlled situation by blocking the excessive brightness in specific regions, thereby achieving overall brightness uniformity across the display apparatus.
Data Source
AI summary
In a display apparatus, pixels are arranged in a matrix defined by gate lines and data lines, and each pixel includes a first sub pixel charged to a first pixel voltage and a second sub pixel charged to a second pixel voltage having a same voltage level as the first pixel voltage. A voltage controller controls a voltage level of the first and second pixel voltages charged in the pixels corresponding to the first through penultimate pixel rows in response to a next gate signal. A dummy voltage controller controls a voltage level of the first and second pixel voltages charged in the pixels corresponding to the last pixel row in response to a dummy gate signal. Where a dummy voltage controller is not included, a black matrix partially covers the efficient display area of the pixels corresponding to the last pixel row.