Pixel Over-Charge Voltage for Incomplete Charging in Display Devices
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Solution Overview
Problem
Increased number of gate lines in liquid crystal display panels leads to shortened charging time for pixels, resulting in incomplete charging and abnormal display due to increased loading of the active area.
Innovation Solution
A display device and method that utilize a gate driver and data driver to manage pixel charging by applying over-charge and recovery voltages during specific turn-on periods, ensuring rapid charging and complete voltage conversion to prevent incomplete pixel charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of gate lines is increased to control more pixels, then the display resolution is improved, but the charging time for each pixel is shortened and pixel charging becomes incomplete
Solution Approach 1:
The patent applies preliminary action by performing an over-charge operation before the normal charge operation. The data driver first drives the data line to an over-charge voltage level before the gate line is fully turned off, ensuring that the pixel capacitor receives sufficient charge in advance. This preliminary charging action compensates for the shortened charging time caused by increased gate line density, allowing complete pixel charging even with reduced available time.
Solution Approach 2:
The patent changes the voltage parameter by introducing an over-charge voltage that is higher than the normal data voltage. The data driver temporarily adjusts the data line voltage to this over-charge level during the turn-on period, enabling faster charging of the pixel capacitor. This parameter change allows the charging process to complete within the reduced time window imposed by increased gate line density.
2Productivity
If the number of gate lines is increased, then more pixels can be controlled, but the active area loading increases causing abnormal display
Solution Approach 1:
The preliminary over-charge operation ensures that pixels are fully charged before the gate line turns off, preventing the abnormal display artifacts that would otherwise occur with incomplete charging. This maintains display reliability while supporting increased pixel control capacity through higher gate line density.
Solution Approach 2:
The patent implements feedback by monitoring the turn-on period timing and adjusting the over-charge voltage application accordingly. The data driver senses the gate line turn-on state and dynamically controls the data line voltage to apply over-charge only when necessary, ensuring reliable pixel charging across all pixels regardless of their position in the matrix.
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 the issue of incomplete pixel charging, enhancing display quality by ensuring all pixels are fully charged, thereby preventing abnormal displays caused by increased gate lines and active area loading.
Implementation Method 1
the data driver is configured to charge the pixel capacitor of the first pixel to a first over-charge voltage via the transistor of the first pixel during an over-charge period
Implementation Method 2
Each of the plurality of pixels comprises a transistor and a pixel capacitor, in which the transistor is electrically coupled to the pixel capacitor
Data Source
AI summary
A display device includes multiple pixels, a gate driver and a data driver. Each pixel includes a transistor and a pixel capacitor electrically coupled to the transistor. The gate driver is configured to turn on the transistor of a first pixel for one time during a first turn-on period of multiple turn-on cycles of a frame cycle of a frame displayed by the display device. The data driver is configured to charge the pixel capacitor of the first pixel via the transistor of the first pixel to a first over-charge voltage and a data voltage during an over-charge period and a recovery period of the first turn-on period. The first over-charge voltage is different from the data voltage. A method for driving the display device is also provided.