Display Panel Reference Pad Layout for Chip Alignment Inspection
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Solution Overview
Problem
Current display devices face challenges in accurately inspecting the alignment of driving circuit chips due to noise interference during the bonding process, which affects the quality of the alignment inspection and can lead to misalignment issues.
Innovation Solution
The display device incorporates a reference pad that does not overlap the driving circuit chip, allowing for accurate alignment inspection by using a vision inspection machine to detect the reference pad's position and subsequently determining the alignment state of the alignment inspection pad and bump, thereby avoiding noise interference and ensuring precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the alignment pad is used for alignment inspection during bonding, then alignment inspection is performed, but noise interference from the bonding process degrades measurement precision
Solution Approach 1:
The patent extracts the reference pad from the bonding area, positioning it in a region that does not overlap with the driving circuit chip. This separation removes the reference pad from the harmful bonding environment, allowing high-precision alignment inspection without noise interference from the bonding process.
Solution Approach 2:
The reference pad serves as an intermediary element for alignment inspection. Instead of directly inspecting the alignment pad during bonding (which suffers from noise), the vision inspection machine detects the reference pad's position as a mediator to determine the alignment state, thereby avoiding direct exposure to noise interference.
2Measurement precision
If the reference pad is positioned to avoid overlapping the driving circuit chip, then noise interference is reduced, but device complexity increases due to additional pad configuration
Solution Approach 1:
The reference pad is configured to serve multiple functions: it provides a reference for alignment inspection, establishes positional relationships with other pads, and enables vision-based detection. This multi-functionality justifies the additional configuration while delivering significant improvements in measurement precision.
Solution Approach 2:
The patent applies local quality by creating a specialized region (non-display area) with specific pad configurations. The reference pad is positioned in this dedicated zone with distinct characteristics from the display area, allowing optimized alignment inspection functionality in a localized region without affecting the overall device structure.
Data Source
AI summary
A display device includes a display panel and a driving circuit chip. The driving circuit chip includes a signal bump and an alignment bump. The display panel includes a pixel disposed in a display area, a signal pad disposed in a non-display area and corresponding to the signal bump, an alignment pad disposed in the non-display area and corresponding to the alignment bump, a reference pad that is disposed in the non-display area, is spaced apart from the alignment pad, and does not overlap the driving circuit chip in a plan view, and a signal line disposed in the display area and the non-display area and electrically connecting the pixel and the signal pad.