Display Device Electrostatic TEG Monitoring
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Solution Overview
Problem
Current display device manufacturing processes fail to accurately monitor static electricity generated during processes like film attachment/detachment, scribing, and laser lift-off, as independent transistors in test element groups do not accurately represent connected transistors in the display area, leading to potential damage and operational issues.
Innovation Solution
A display device design featuring a display portion with display pixels and a dummy portion with electrostatic test element groups (TEGs) in the periphery, where electrostatic transistors are connected through source and drain electrodes, and surrounded by guard rings to accurately monitor static electricity and prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an independent transistor is used in the TEG, then the structure is simple and easy to manufacture, but it cannot accurately represent the connected transistors in the display area, leading to inaccurate static electricity monitoring
Solution Approach 1:
The TEG is divided into multiple transistor units (first, second, third, and fourth transistor units) that are connected in a specific configuration. Each unit represents a portion of the display area transistors, and their collective behavior accurately reflects the static electricity effects on the connected transistors in the display area, resolving the contradiction between structural simplicity and measurement accuracy.
Solution Approach 2:
The TEG transistors are designed to copy the electrical characteristics and connection topology of the actual display area transistors. By creating a scaled-down replica of the transistor network with similar connection patterns, the TEG can accurately simulate and monitor static electricity effects without requiring complex full-scale testing structures.
2Measurement precision
If measurement processes are performed on substantial elements, then direct monitoring is achieved, but the processed elements are damaged
Solution Approach 1:
The TEG serves as an intermediary structure that substitutes for the substantial display area transistors in the measurement process. By performing static electricity monitoring on the TEG transistors instead of the actual display transistors, the patent achieves accurate indirect measurement without causing damage to the valuable processed elements in the display area.
3Measurement precision
If guard rings are added around electrostatic transistors, then static electricity monitoring accuracy is improved, but device complexity increases
Solution Approach 1:
Guard rings are added selectively around specific electrostatic transistors in the TEG that are most susceptible to or indicative of static electricity effects. This localized approach improves measurement precision for critical transistors while avoiding the need to add guard rings to all transistors, thereby controlling the increase in device complexity.
Data Source
AI summary
A display device according to an exemplary embodiment of the present invention includes a display portion including a plurality of display pixels displaying an image and a dummy portion including a plurality of dummy pixels formed in a periphery region of the display portion. An electrostatic test element group (TEG) may be formed in at least one of the dummy pixels.