Wire Test Device for Detecting Defects in OLED One-Sheet Substrates
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Solution Overview
Problem
Conventional methods for testing one-sheet substrates in organic light emitting display panels lack accurate electrical testing, often relying on visual inspection and are prone to errors due to damage from chip-on-glass (COG) pads and multiplexing circuit arrangements.
Innovation Solution
A test device and method that utilize demultiplexing switches and control switches to transmit wire test signals to detect defects in spider wires, allowing for accurate detection of defects in both first and second wires through light emitting states of pixel arrays, reducing the risk of errors associated with COG pad damage and multiplexing circuit issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct contact testing with COG pad is used, then electrical testing capability is improved, but damage to COG pad and testing errors increase
Solution Approach 1:
The patent introduces wire test signals as an intermediary testing method. Instead of directly contacting the COG pad with test probes, the system transmits test signals through dedicated wire paths (first wires and second wires) that are alternatively disposed below the demultiplexing switches. This intermediary wire-based approach enables electrical testing while avoiding direct contact with and potential damage to the COG pad structure.
Solution Approach 2:
The patent segments the testing process into two separate wire groups (first wires and second wires) that are alternatively disposed. By dividing the wire testing into alternating groups passed through the demultiplexing switches, the system can test wires in a segmented manner, reducing the complexity of direct COG pad contact and minimizing damage risk while maintaining comprehensive testing coverage.
2Device complexity
If multiplexing circuit is arranged below bump for one-sheet testing, then testing integration is improved, but testing errors and reliability issues increase
Solution Approach 1:
The patent inverts the conventional approach by placing the demultiplexing switches below the bump structure rather than arranging multiplexing circuits there. This inversion allows the wire test signals to be transmitted through alternatively disposed first and second wires that pass under the bump, enabling integrated testing while avoiding the reliability issues associated with traditional multiplexing circuit arrangements in that location.
3Ease of operation
If visual test is used for one-sheet substrate, then simplicity is maintained, but testing accuracy and defect detection capability decrease
Solution Approach 1:
The patent replaces the mechanical visual inspection method with an electrical wire testing system. Wire test signals are transmitted through alternatively disposed first and second wires via demultiplexing switches, and defects are detected by monitoring the electrical response. This substitution maintains operational simplicity through automated signal transmission while dramatically improving defect detection accuracy through precise electrical measurements.
Data Source
AI summary
A test device for a display device including a plurality of demultiplexing switches connected to a plurality of data lines in accordance with the present invention includes: a one-sheet test device configured to include a plurality of control switches connected to the demultiplexing switches through a plurality of wires; and a wire test device configured to transmit wire test signals for detecting defects in the wires to a pad connected to the control switches. The wire test device transmits the wire test signals to the pad to detect defects in first wires of the wires and then detect defects in remaining second wires thereof, and the first wires and the second wires are alternatively disposed below the demultiplexing switches to constitute paths for signals transmitted to the demultiplexing switches.