Gate Delay Sensing Circuit for Display Panel RC Compensation
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Solution Overview
Problem
As display panel sizes increase, gate lines become longer, leading to distortion and reduced swing width of gate signals due to resistive-capacitive (RC) delay, which affects the performance and manufacturing consistency of liquid crystal display apparatus.
Innovation Solution
Incorporating a gate delay sensing circuit with a time-to-digital converter and digital comparator to detect and compensate for RC delay by converting feedback gate signals into digital activation values, and using a power supply circuit to adjust gate-on and gate-off voltages based on digital high and low voltage values, thereby maintaining signal integrity and pixel charging rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display panel size is increased, then the display area is improved, but the gate signal distortion increases due to RC delay
Solution Approach 1:
The patent implements a feedback mechanism by sensing the actual gate signal voltage at the far end of the gate line and using this information to adjust the gate drive voltage. The sensing circuit measures the gate signal characteristics and feeds this information back to the gate driver, enabling real-time compensation for RC delay effects and maintaining signal integrity in large displays.
Solution Approach 2:
The patent dynamically changes the gate drive voltage parameter based on the measured gate signal characteristics. By adjusting the gate voltage level according to the sensed feedback, the system compensates for RC delay variations caused by different display sizes, ensuring consistent pixel switching performance across various display areas.
2Area of stationary object
If the gate line length is increased, then the display area is improved, but the swing width of gate signal is reduced
Solution Approach 1:
The sensing circuit continuously monitors the gate signal swing width at the far end of the gate line and provides feedback information about the actual voltage levels. This feedback enables the gate driver to adjust its output to maintain the required swing width, ensuring reliable pixel switching even in large displays with long gate lines.
Solution Approach 2:
The gate drive voltage is made dynamic rather than fixed. The system continuously adapts the gate voltage parameters based on real-time sensing feedback, allowing the gate driver to compensate for variations in swing width caused by different display sizes and gate line lengths, thereby maintaining signal reliability.
3Manufacturing precision
If a gate delay sensing circuit is added, then the RC delay compensation is improved, but the device complexity increases
Solution Approach 1:
The gate driver circuit performs self-diagnosis and self-adjustment by incorporating a sensing circuit that monitors its own output. The gate driver senses its gate signal characteristics and automatically adjusts its drive parameters without requiring external intervention or complex external compensation circuits, thereby achieving RC delay compensation with minimal additional complexity.
Solution Approach 2:
The sensing circuit is integrated within the gate driver structure, merging the compensation function with the existing gate drive circuitry. By combining the sensing and driving functions in a single integrated unit, the patent achieves RC delay compensation without significantly increasing overall device complexity, as the sensing components share the same physical space and control logic with the gate driver.
Data Source
AI summary
A display apparatus includes a display panel including a plurality of first gate lines, a first gate driver connected to first ends of the plurality of first gate lines, a second gate driver connected to second ends of the plurality of first gate lines, a feedback line connected adjacent to the first end of one of the plurality of first gate lines, and a gate delay sensing circuit connected to the feedback line. The gate delay sensing circuit includes a time-to-digital converter and a digital comparator. The time-to-digital converter converts an activation time of a feedback gate signal into a digital activation value. The feedback gate signal is retrieved from the feedback line. The digital comparator generates a digital delay value based on the digital activation value. The digital delay value indicates resistive-capacitive (“RC”) delay of the one of the plurality of first gate lines connected to the feedback line.