Pixel Circuit Test Unit for Display Panel Defect Detection
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Solution Overview
Problem
Existing display panels face challenges in effectively inspecting pixel circuits, particularly in identifying defects such as improper transistor operation, short-circuits, or cuts in the lines connecting thin-film transistors (TFTs), which can disrupt the normal supply of driving current to light emitting elements.
Innovation Solution
The implementation of a test unit within the display panel's pixel circuit, comprising a test thin-film transistor (TFT) connected to specific nodes and lines, allows for the supply of test voltages and signals to evaluate the operation of TFTs and other transistors in the pixel circuit, thereby identifying any malfunctions or defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a test unit is added to the pixel circuit, then the ability to detect defects in TFT operation and line connections is improved, but the device complexity increases
Solution Approach 1:
The pixel circuit is divided into functional segments: a first circuit part for normal operation, a second circuit part for signal output, and a test unit for defect detection. The test unit includes a test TFT connected between nodes in these circuit parts, allowing independent testing functionality to be integrated without completely redesigning the entire pixel circuit.
Solution Approach 2:
The test unit is designed to perform multiple testing functions within a single integrated structure. The test TFT can detect various defects including improper transistor operation, short-circuits, and cuts in connecting lines, making the test unit a multi-functional component that addresses multiple detection needs simultaneously.
2Reliability
If inspection processes are enhanced to identify all defects, then the quality of display panels is improved, but the manufacturing time increases
Solution Approach 1:
The test unit enables defect detection to be performed during the manufacturing process itself, before the display panel is completed and shipped. By incorporating the test TFT and associated testing capability into the pixel circuit structure, defects can be identified and addressed in advance, preventing defective products from reaching the customer and reducing the need for post-manufacturing inspection and recall processes.
Data Source
AI summary
A display panel includes: a plurality of pixels, each of which includes a light emitting element and a pixel circuit for driving the light emitting element; a plurality of scan lines connected to the pixel circuit; and a data line connected to the pixel circuit. The pixel circuit includes: a transfer capacitor connected to a first node and a second node; a first circuit part including the first node; a second circuit including the second node and connected with the light emitting element; and a test unit connected to the first circuit part and the second circuit part.