Transflective LCD Pixel Structure for Voltage-Aligned Curves
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Solution Overview
Problem
Single-gap transflective LCDs face a discrepancy in transmissivity and reflectivity curves, where peak values do not occur in the same voltage range, affecting image color and contrast, especially in low brightness regions.
Innovation Solution
The introduction of a pixel structure with sub-pixel segments featuring separate data and gate lines to control voltage, along with adjustment storage capacitors, allows for shifting the reflectivity curve to align with transmissivity, and connecting transmissive and reflective electrodes to retain part of the unshifted reflectivity curve, enabling multi-threshold harmonization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the reflectivity curve is shifted to align with transmissivity using adjustment storage capacitors, then the peak values of transmissivity and reflectivity occur at the same voltage range, but a major discrepancy between transmissivity and reflectivity is created in the low brightness region
Solution Approach 1:
The pixel structure is divided into transmission area and reflection area with separate electrode arrangements. The transmissive electrode and reflective electrode are controlled independently through separate gate lines and data lines, allowing distinct voltage control for each functional region to resolve the curve alignment issue without compromising low brightness quality
Solution Approach 2:
Different electrode regions are assigned different charge storage capacities tailored to their specific functions. The adjustment storage capacitor is specifically connected to the reflective electrode to modify its voltage characteristics locally, while the transmissive electrode maintains its original capacitance for optimal transmission performance
2Manufacturing precision
If separate control of transmissive and reflective electrodes is implemented, then transmissivity and reflectivity can be optimized independently, but the device complexity increases due to additional data lines and gate lines
Solution Approach 1:
Multiple sub-pixel segments share common control lines (common gate line, common data line, common adjustment storage capacitor) to reduce the total number of control lines. The independent control is achieved through selective activation of specific gate lines and data lines for each sub-pixel segment while sharing the infrastructure
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
This approach enables transmissivity and reflectivity to reach optimal values at the same applied voltage, significantly improving image quality and reducing discrepancies in low brightness regions, thereby enhancing color and contrast.
Implementation Method 1
The first and second gate lines can be separately set at a first control state and a second control state. The ratio of the first charge storage capacitor to the second charge storage capacity can be adjusted by an adjustment storage capacitor and controlled according to the states of the gate lines.
Implementation Method 2
A transflective liquid crystal display makes use of both the back-light source and ambient light. In the transmission area, light from a back-light source enters the pixel area through a lower substrate, and goes through a liquid crystal layer, a color filter and the upper substrate. In the reflection area, light encountering the reflection area goes through an upper substrate, the color filter and the liquid crystal layer before it is reflected by a reflective layer.
Data Source
AI summary
A transflective liquid crystal display having a plurality of pixels, each pixel having a plurality of color sub-pixels. Each sub-pixel comprises a reflective electrode, a transmissive electrode connected to a secondary reflective electrode. The transmissive electrode is associated with a color filter, while one only of the reflective electrode and the secondary reflective electrode is associated with a color filter. The transmissive electrode is associated with a first charge storage capacitance. The reflective electrode is associated with a second charge storage capacitance which is adjustable depending on the operating states of the liquid crystal display.