VCOM Voltage Difference Reduction in LCD Displays
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Solution Overview
Problem
Liquid crystal displays (LCDs) face issues with undesirable image quality due to voltage differences between common voltage layers (VCOMs), causing color variations between different portions of the display.
Innovation Solution
A method is implemented to control the removal of the activation signal from pixels by detecting and adjusting the voltage difference between VCOMs, ensuring a consistent voltage across all layers by partially closing the TFT gates at a predetermined rate, thereby reducing the voltage difference and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a segmented VCOM configuration is used to reduce voltage differences between different portions of the display, then image quality uniformity is improved, but device complexity increases due to the need for multiple VCOM layers and coordinated control
Solution Approach 1:
The display is divided into multiple segments, each with its own VCOM layer. This segmentation allows independent voltage control for different portions of the display, enabling the reduction of voltage differences between segments and improving overall image quality uniformity.
Solution Approach 2:
The patent implements dynamic control of the segmented VCOM layers by adjusting the timing and duration of activation signals. The gate control device dynamically adjusts when each VCOM layer is active, allowing the system to adapt to different display conditions and maintain voltage balance across segments.
2Speed
If the activation signal is removed quickly from pixels, then the display responds faster to changes, but voltage differences between VCOMs increase due to kickback voltage effects
Solution Approach 1:
The gate control device performs preliminary action by partially closing TFT gates at a predetermined rate before completely removing the activation signal. This preliminary partial closing action begins the voltage equalization process in advance, allowing the system to maintain voltage balance while still achieving fast response.
Solution Approach 2:
The system uses feedback from voltage detection to control the removal of the activation signal. The gate control device monitors voltage differences between VCOMs and adjusts the signal removal timing accordingly, creating a closed-loop control system that balances speed and voltage uniformity.
Data Source
AI summary
Methods and devices for reducing a voltage difference between common voltage layers (VCOMs) of a display are provided. In one example, a method may include supplying an activation signal to a row of pixels of the display to activate the row of pixels. The method may also partially removing the activation signal from the row of pixels at a predetermined rate. The method may include detecting a voltage difference between a first VCOM of a first set of pixels of the display and a second VCOM of a second set of pixels of the display after the activation signal has been partially removed. The method may also include controlling removal of the activation signal from the row of pixels based at least partially on the detected voltage difference.