Pixel Structure Charge Sharing Voltage Control
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Solution Overview
Problem
Conventional liquid crystal display pixel structures face challenges in accurately controlling gray level voltages, particularly due to the influence of previous frame voltages in charge-sharing mechanisms, leading to inconsistent gray levels across sub-pixels.
Innovation Solution
A pixel structure where the charge sharing capacitor is coupled to a variable voltage, allowing for precise control of gray level voltages by resetting the capacitor voltage before charge sharing, ensuring sub-pixels reach desired voltages during each display period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If charge sharing capacitor keeps previous frame voltage, then sub-pixel can maintain previous gray level, but sub-pixel cannot accurately reach desired voltage level for current frame
Solution Approach 1:
The patent applies preliminary action by resetting the charge sharing capacitor voltage to a predetermined level before charge sharing occurs. This preliminary reset ensures that the capacitor starts from a known state, allowing the sub-pixel to accurately reach the desired voltage level for the current frame without being influenced by previous frame voltages.
Solution Approach 2:
The patent changes the voltage parameter of the charge sharing capacitor from a static previous-frame voltage to a dynamically controlled voltage that is reset to a predetermined level. This parameter change enables precise control of the liquid crystal capacitor voltage while maintaining stability during the display period.
2Reliability
If use two transistors type pixel structure, then image sticking problem is solved, but number of gate lines or data lines must be doubled increasing manufacturing cost
Solution Approach 1:
The patent makes the charge sharing capacitor multi-functional by using it both for maintaining gray level stability during the display period and for enabling accurate voltage control through reset. This universal usage of the existing capacitor structure eliminates the need for additional transistors and lines, maintaining reliability while avoiding increased device complexity.
Solution Approach 2:
The charge sharing capacitor serves itself by being reset to a predetermined voltage level, automatically preparing itself for the next charge sharing operation without requiring external intervention or additional control circuits. This self-service mechanism simplifies the overall pixel structure.
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 solution enables accurate and consistent gray level voltage control across sub-pixels, improving image quality by minimizing the impact of previous frame voltages and enhancing the overall display performance.
Implementation Method 1
a charge sharing capacitor coupled to a variable voltage, wherein when the second gate line turns on the third switching transistor, the second liquid crystal capacitor and the charge sharing capacitor are charge-shared
Data Source
AI summary
A pixel structure includes a first sub-pixel and a second sub-pixel. The first sub-pixel includes a first switching transistor and a first liquid crystal capacitor, wherein when the first switching transistor is turned on, the first liquid crystal capacitor is biased to a first gray level voltage. The second sub-pixel includes a second switching transistor, a second liquid crystal capacitor, a third switching transistor, a charge sharing capacitor and a fourth switching transistor, wherein when the second switching transistor is turned on, the second liquid crystal capacitor is biased to the first gray level voltage; when the fourth switching transistor is turned on, the charge sharing capacitor is reset to a predetermined voltage; and when the third switching transistor is turned on, the second liquid crystal capacitor and the charge sharing capacitor are charge-shared to a second gray level voltage through the third switching transistor.