Dual-Layer Semiconductor Test Unit for Display Defect Detection
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Solution Overview
Problem
As display devices increase in size, the non-display area for testing wirings and pixels has decreased, making it challenging to effectively detect resistive and short defects in the smaller test units.
Innovation Solution
The display device incorporates a test unit with a switching element that includes a gate electrode, a first semiconductor layer, and a second semiconductor layer, where one layer is an oxide semiconductor and the other is silicon-based, allowing for efficient detection of defects through a test control line and test signal line, enabling both resistive and short defect detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the display device size increases, then the display area increases, but the non-display area for testing decreases
Solution Approach 1:
The patent utilizes a dual-layer semiconductor structure (first semiconductor layer and second semiconductor layer) arranged in the vertical dimension to increase the functional capacity within the limited planar area of the non-display region. This vertical stacking allows more test units to be accommodated without increasing the horizontal footprint.
Solution Approach 2:
The test unit is divided into multiple functional components including first switching elements, second switching elements, test control lines, and test signal lines, each performing specific functions. This segmentation allows for compact arrangement and efficient use of the limited non-display area while maintaining comprehensive testing capabilities.
2Area of moving object
If the non-display area decreases, then the display area increases, but the ability to detect resistive and short defects deteriorates
Solution Approach 1:
The patent changes the electrical parameters of the test unit by using dual-layer semiconductor structures with different material properties (oxide semiconductor and silicon-based semiconductor). This allows for optimized electrical characteristics that enhance the sensitivity and accuracy of resistive and short defect detection within the constrained test area.
Solution Approach 2:
The switching elements are constructed using composite semiconductor structures combining oxide semiconductor layers and silicon-based semiconductor layers. This composite approach leverages the complementary properties of different materials to achieve both compact size and high reliability in defect detection.
3Reliability
If more test units are arranged in a narrow area, then defect detection coverage increases, but the device complexity increases
Solution Approach 1:
The test unit design uses universal switching elements (first and second switching elements with similar structures) that can perform multiple testing functions. This multi-functionality allows comprehensive defect detection coverage without proportionally increasing structural complexity, as the same basic building blocks are reused throughout the test unit.
Solution Approach 2:
The patent merges the first switching elements and second switching elements into a integrated test unit structure with shared control and signal lines. This consolidation reduces overall complexity compared to having separate independent test circuits, while still maintaining comprehensive defect detection capabilities.
Data Source
AI summary
A display device includes a pixel connected to a data line, a data pad connected to the data line, and a first test area. The first test area includes a test control line transmitting a test control signal, a test signal line transmitting a test signal, and a first switch connected to the data pad. The first switch includes a gate electrode connected to the test control line, first and second semiconductor layers overlapping the gate electrode, a source electrode connected to the first and second semiconductor layers, and a drain electrode spaced from the source electrode and connected to the first and second semiconductor layers. The source electrode and the drain electrode are connected to the test signal line and data pad, respectively. One of the first or second semiconductor layers includes an oxide semiconductor and the other of the first or second semiconductor layer includes a silicon-based semiconductor.