Liquid Crystal Display Panel Test Pixel Voltage Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for measuring pixel voltage in liquid crystal display panels face challenges, including disruption of normal display due to test points and small capacitance between pixel and common electrodes, leading to measurement failures.
Innovation Solution
A liquid crystal display panel design incorporating an array substrate and color filter substrate with invalid pixels, a test pixel, and a test switch transistor, where the test pixel is in an off state during normal operation and switched on for measurement, with a test terminal in a shielding region to prevent voltage leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a test point is designed in the display region, then pixel voltage can be measured, but normal display is affected causing abnormal display
Solution Approach 1:
The patent divides the pixel array into two distinct segments: valid pixels for normal display and invalid pixels for measurement. The test pixel is specifically located in the invalid pixel region, separating the measurement function from the display function. This segmentation allows the test point to be designed without affecting the display region, as the test pixel is electrically isolated from the valid pixels through separate gate control.
Solution Approach 2:
The measurement function is extracted from the display region and placed in the invalid pixel region. The test pixel is taken out from the functional display area and positioned in a region that does not contribute to normal display output. This extraction allows measurement activities to occur without interfering with the display function, as the test pixel is controlled by a separate gate driving unit.
2Measurement precision
If the test point is externally connected to measure pixel voltage, then voltage can be accessed, but the small capacitance causes voltage to be released in the air leading to measurement failures
Solution Approach 1:
The patent applies preliminary anti-action by pre-charging the test pixel through controlled gate signals before external connection. The gate driving unit outputs specific voltage levels to charge the pixel electrode and storage capacitor, establishing a stable voltage state before the test point is externally connected. This preliminary charging prevents voltage leakage during measurement, as the capacitance is already charged and maintained at a stable potential level.
Solution Approach 2:
The gate driving unit performs preliminary actions by outputting control signals to charge the test pixel's capacitance before measurement. The pixel voltage is pre-established through gate control, ensuring that when the test point is externally connected, the voltage is already stable and ready for accurate measurement. This preliminary action prevents voltage release issues by ensuring proper charging sequence.
Data Source
AI summary
The present application provides a liquid crystal display panel and a display device. Invalid pixels of the liquid crystal display panel include a test pixel. In this structure, when no tests are required, the test pixel is in an off state, and there is no voltage difference between a pixel electrode and a common electrode to cause rotation of liquid crystals. When a test is required, the test pixel is in an on state, and the pixel electrode is disconnected from the common electrode to cause a voltage difference, so that the liquid crystals are normally rotated.