OLED Panel Test Circuit Integration for Yield Improvement
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Solution Overview
Problem
The manufacturing process of organic light-emitting display panels is complex and has low reliability and yield due to the need for multiple leads in traditional TAB techniques, and high-density integrated circuits increase costs.
Innovation Solution
An organic light-emitting display panel design that includes a pixel unit with a test unit for early defect detection, reducing dead space and integrating a driving circuit directly into the pixel circuit array substrate, allowing for array and cell tests to identify and repair defects before further processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TAB technique is used to couple driving circuits to pixel array substrate, then connection reliability is improved, but manufacturing complexity and cost increase due to multiple leads and high-density integrated circuits
Solution Approach 1:
The patent extracts the test function from the display function by introducing dedicated test signal lines separate from the data signal lines. This allows test operations to be performed independently without interfering with normal display operations, and enables early defect detection before final assembly. The test circuitry is integrated into the pixel circuit substrate itself rather than requiring separate external testing equipment.
Solution Approach 2:
The patent performs array tests and cell tests at early stages of the manufacturing process, before the pixel array substrate is finally assembled with the driving circuit. By testing pixel circuits and light-emitting devices early using integrated test signal lines, defects can be identified and repaired before subsequent manufacturing steps, improving overall yield without requiring complex post-assembly testing equipment.
2Ease of manufacture
If driving circuit is directly integrated into pixel circuit array substrate (COG type), then manufacturing process is simplified, but defect detection capability is reduced
Solution Approach 1:
The patent segments the signal lines into two distinct sets: data signal lines for normal display operation and test signal lines for defect detection. This segmentation allows the test function to be integrated into the COG-type pixel circuit substrate without interfering with the simplified manufacturing process. The test signal lines are routed through the same substrate layers but remain electrically separate from the data signal lines, enabling independent testing while maintaining manufacturing simplicity.
Solution Approach 2:
The pixel circuit substrate is designed with multi-functionality, serving both as the display function carrier and as the test function platform. The same substrate that drives the display also contains integrated test signal lines and test circuitry that can detect defects in pixel circuits and light-emitting devices. This eliminates the need for separate testing equipment or complex post-assembly testing processes.
3Productivity
If test unit is added to detect defects early, then manufacturing yield is improved, but dead space and device complexity increase
Solution Approach 1:
The patent merges the test function with the pixel circuit substrate by integrating test signal lines and test circuitry directly into the same substrate that drives the display. Rather than adding separate testing equipment or external test circuits that would occupy additional space, the test functionality is combined with the existing pixel circuit structure. The test signal lines share the substrate real estate with the data signal lines, minimizing additional dead space while enabling early defect detection to improve manufacturing yield.
Data Source
AI summary
An organic light-emitting display panel includes a pixel unit including a plurality of pixels respectively located at intersections between scan lines and data lines and displaying different colors; a plurality of pads respectively coupled to ends of the data lines; and a test unit selectively performing an array test to detect a defect of a pixel circuit of the pixels or a cell test to detect a defect of a light-emitting device of the pixels.