Column Inversion LCD Panel Charge Control Transistor
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Solution Overview
Problem
Liquid crystal display panels using column inversion driving mode suffer from nonuniform image display due to charge differences between adjacent pixels caused by alternating positive and negative voltages, leading to uneven brightness across the screen.
Innovation Solution
Incorporating a charge control thin film transistor into the pixel driving circuit, with a clock signal providing alternating high and low voltage levels to control the charging of pixels in odd and even columns, ensuring that each column receives balanced positive and negative voltages, thereby compensating for charge differences and achieving uniform frame display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If column inversion driving mode is used to drive the liquid crystal display panel, then the liquid crystal molecules can be rotated with certain frequency to prevent fixed leaning, but the voltage difference between positive and negative source voltages and gate voltage causes different charge effects, resulting in nonuniform brightness
Solution Approach 1:
The patent applies different charge durations to different columns: odd columns receive positive voltage for duration T1 while even columns receive negative voltage for duration T2, where T1 ≠ T2. This local differentiation in charging parameters compensates for the inherent voltage differences between adjacent columns, ensuring uniform brightness across the display while maintaining the alternating polarity required for liquid crystal stability
Solution Approach 2:
The patent changes the temporal parameter (charge duration) of the driving voltage to resolve the brightness nonuniformity issue. By adjusting the duty cycle of the clock signal that controls the charge control transistors, the patent modifies the effective voltage application time for different columns, thereby compensating for charge effects and achieving uniform display brightness
2Adaptability or versatility
If alternating positive and negative voltages are applied to adjacent columns to achieve inversion driving, then liquid crystal activity is maintained, but charge differences between adjacent pixels cause uneven brightness
Solution Approach 1:
The patent implements local quality by making the charge control transistor parameters column-specific: odd columns use one charge duration configuration while even columns use another. This allows the system to maintain alternating polarity inversion driving capability while locally adjusting charge characteristics to achieve uniform brightness across all columns
Solution Approach 2:
The patent introduces dynamic control through the clock signal that alternately activates charge control transistors in odd and even columns with different duty cycles. This dynamic adjustment of charge timing allows the system to adaptively compensate for voltage differences between adjacent columns while maintaining the alternating inversion driving mode
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 balances the charge effects of adjacent pixels by adjusting the voltage levels and pulse widths of the clock signal, resulting in a uniform frame display effect by ensuring that the charge duration of negative voltage is longer than that of positive voltage, thus addressing the nonuniformity issue.
Implementation Method 1
The liquid crystal display panel comprises a plurality of pixels arranged in array. Each pixel is electrically coupled to one thin film transistor (TFT), and a gate (Gate) of the TFT is coupled to a horizontal scan line, and a drain is coupled to a vertical data line, and a source is coupled to a pixel electrode. The enough voltage is applied to the level scan line, and all the TFTs electrically coupled to the scan line are activated. Thus, the signal voltage on the data line can be written into the pixel to control the transmittances of liquid crystals to achieve the display effect.
Implementation Method 2
The liquid crystal molecules have a certain property, which is that the liquid crystal molecules will be polarized if the voltage of the same direction is applied to the liquid crystal molecules with a long period of time. Even the voltage disappears, the property of the liquid crystal molecules will be destroyed and can no longer be rotated due to the variation of the electrical field.
Data Source
AI summary
The present invention provides a liquid crystal display panel of column inversion driving mode and a driving method thereof. With adding the charge control thin film transistor (T2) in the pixel driving circuit and according to the positive, negative voltages provided by the data line, the high, low voltage levels and pulse widths of the clock signal (CK) provided to the gate of the charge control thin film transistor (T2) are adjusted to control the times of respectively charging the pixels of two adjacent column with the positive, negative voltages, which can balance the charge effects of the pixels of two adjacent column with the positive, negative voltages to compensate the charge difference to the pixels of two adjacent columns caused by the positive, negative voltages for making the frame display effect uniform.