VA Liquid Crystal Display Pixel Sub-Pixel Voltage Control
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Solution Overview
Problem
Liquid crystal displays with vertically aligned mode suffer from color wash-out when viewed from oblique angles due to transmittance-voltage characteristics, leading to color shift and reduced display quality, and existing Half-tone technologies complicate the circuit and increase power consumption.
Innovation Solution
A liquid crystal display with a pixel unit comprising two sub-pixels, each with a thin film transistor and storage capacitor, where the sub-pixels have different electric potentials generated by coupling different voltage sources, simplifying the circuit and reducing power consumption while avoiding color shift by combining distinct transmittance-voltage characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Half-tone technology is used to improve viewing angle and eliminate color wash-out, then display quality is improved, but circuit complexity increases and power consumption increases
Solution Approach 1:
The pixel electrode is divided into two separate pixel electrodes (first pixel electrode and second pixel electrode), each controlled by independent thin film transistors. This segmentation allows different voltage applications to create distinct T-V characteristics that compensate for viewing angle effects, eliminating color wash-out while maintaining circuit simplicity.
Solution Approach 2:
The invention applies different voltage parameters to the two pixel electrodes to generate different T-V characteristics. By controlling the voltage applied to each electrode separately, the system achieves monotonic transmittance characteristics across viewing angles without requiring complex circuitry or additional power consumption.
2Reliability
If Half-tone technology with two scanning lines or two data lines is used to generate different Gamma curves, then color shift is improved, but aperture ratio is reduced and circuit is complicated
Solution Approach 1:
The invention uses a single scanning line and single data line to control both pixel electrodes through two thin film transistors. This multi-functional approach allows the same signal lines to serve dual purposes, generating different Gamma curves for color shift compensation without requiring additional scanning lines or data lines, thus maintaining aperture ratio.
Solution Approach 2:
The pixel unit is segmented into two independently controllable regions (first pixel electrode and second pixel electrode), each with its own thin film transistor. This segmentation enables different voltage applications to create distinct T-V characteristics for color shift compensation while using shared signal lines to avoid aperture ratio reduction.
3Adaptability or versatility
If VA mode is used to provide wider viewing range, then view angle is improved, but color wash-out occurs at oblique directions
Solution Approach 1:
The invention changes the voltage parameters applied to the two pixel electrodes to create different T-V characteristics. By adjusting the voltage levels and waveforms for each electrode separately, the system achieves monotonic transmittance characteristics that maintain color accuracy across wide viewing angles while preserving the wide viewing range benefit of VA mode.
Solution Approach 2:
The invention combines two different T-V characteristics (from first and second pixel electrodes) into a single pixel unit output. This composite approach merges the advantages of different voltage characteristics to achieve both wide viewing range and color accuracy, eliminating the color wash-out phenomenon inherent in conventional VA mode displays.
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
The solution effectively addresses color shift issues at wide viewing angles, simplifies the circuit, and reduces power consumption by generating monotonic transmittance-voltage characteristics without the need for additional scanning lines or voltage sources, enhancing display quality and efficiency.
Implementation Method 1
Liquid crystal displays have been used in various electronic devices. A Vertically Aligned Mode (VA mode) liquid crystal display is developed to provide a wider viewing range.
Implementation Method 2
Each sub-pixel includes a storage capacitor. The two storage capacitors are coupled to different voltage sources to modify the pixel electrodes to make the two pixel electrodes have different electric potentials.
Data Source
AI summary
The present invention provides a liquid crystal display including a plurality of pixel units defined by scanning lines and data lines. Each pixel unit includes two sub-pixels. Each sub-pixel includes a storage capacitor. The two storage capacitors in a pixel unit are connected to different voltage sources to modify the electric potential of the pixel electrodes.