Gate Drive Circuit Precharging for LCD Pixel Charging Delay
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Solution Overview
Problem
In liquid crystal display devices, the presence of resistors and parasitic capacitors on gate driving lines causes delays in drive voltage transmission, leading to inadequate charging of pixel capacitors, resulting in inaccurate pixel displays.
Innovation Solution
A gate driving method where a gate drive circuit outputs a preset first voltage greater than the turn-off voltage to the gate driving line before the transistor turn-on time, followed by the turn-on voltage at the turn-on time, and then the turn-off voltage at the turn-off time, to precharge the parasitic capacitor and reduce delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a gate drive circuit outputs drive voltage directly to the gate driving line at transistor turn-on time, then the circuit structure is simple, but the parasitic capacitor on the gate driving line causes delay in voltage transmission, leading to insufficient charging time for pixel capacitors
Solution Approach 1:
The gate drive circuit outputs a first voltage to the gate driving line before the transistor turn-on time to precharge the parasitic capacitor. This preliminary action ensures that when the turn-on voltage is output at the scheduled turn-on time, the voltage transmission delay is minimized, allowing sufficient charging time for the pixel capacitor without extending the overall frame time.
2Manufacturing precision
If the gate drive circuit outputs turn-on voltage to far away pixel transistors, then all pixel transistors in the row are controlled, but the voltage transmission delay causes inaccurate display for distant pixels
Solution Approach 1:
The gate drive circuit precharges the parasitic capacitor on the gate driving line by outputting a first voltage before the transistor turn-on time. This preliminary charging action compensates for the RC delay effect caused by resistors and parasitic capacitors on the gate driving line, ensuring that the turn-on voltage reaches distant pixel transistors with minimal delay, thereby improving pixel display accuracy across the entire row.
3Reliability
If the gate drive circuit uses a single voltage output mode, then the control logic is simple, but it cannot compensate for the RC delay effect on the gate driving line
Solution Approach 1:
The gate drive circuit employs a two-stage voltage output mode: first outputting a first voltage to precharge the parasitic capacitor, then outputting the turn-on voltage to control pixel transistors. This dual-stage control logic, while slightly more complex than single-mode control, reliably compensates for the RC delay effect on the gate driving line, ensuring consistent and accurate voltage transmission to all pixel transistors in the row.
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 method reduces the delay in transmitting the turn-on voltage, increases the charging time for pixel capacitors, and improves the accuracy of pixel display by ensuring timely and efficient charging.
Implementation Method 1
There exists a resistor and a parasitic capacitor on the gate driving line of each pixel row, which will give rise to delay of the drive voltage transmission
Implementation Method 2
When the drive voltage is a high level transistor turn-on voltage VGH, the pixel transistor is turned on
Implementation Method 3
When a pixel transistor is turned on, a data voltage will charge the respective pixel capacitor through the pixel transistor. The charged pixel capacitor can control the output of corresponding optical signals
Data Source
AI summary
The present invention discloses a gate driving method of a pixel transistor and a gate drive circuit, as well as a display device including the gate drive circuit, which falls within the field of display technology. The method comprises the steps of: a gate drive circuit outputting a preset first voltage to a gate driving line of a pixel row prior to a transistor turn-on time of the pixel row, wherein the first voltage is greater than a transistor turn-off voltage; and the gate drive circuit outputting a transistor turn-on voltage to the gate driving line of the pixel row when it reaches the transistor turn-on time. Use of the present invention can improve the accuracy of pixel display.