Display Panel Test Structure with Ring-Shaped Trenches
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Solution Overview
Problem
Conventional methods for electrical inspection of signal lines in display panels require destructive cleaving and piercing of substrates, complicating the process and hindering imaging quality by performing inspections in non-display regions.
Innovation Solution
A test structure located in a buffer display region of the panel, featuring a substrate, signal lines, insulation, planar, and electrode layers with ring-shaped trenches, allowing electrical inspection without substrate cleaving or piercing, and maintaining imaging quality by using a fusing process to connect test electrodes to signal lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a probe is employed to directly contact the end of the signal line for electrical inspection, then the electrical properties of the signal line can be measured, but the substrate must be destructively cleaved and pierced which complicates the inspection process and consumes significant time
Solution Approach 1:
The test structure is pre-integrated into the display panel during manufacturing, with test electrodes positioned at specific locations. This preliminary preparation eliminates the need for destructive substrate cleaving during inspection, as the probe can directly contact the pre-positioned test electrodes through openings in the planar layer.
Solution Approach 2:
The test structure serves as an intermediary between the signal line and the measurement probe. Instead of directly probing the signal line end (which requires substrate destruction), the probe contacts the test electrode that is electrically connected to the signal line through the conductive channel, enabling non-destructive measurement.
2Measurement precision
If the substrate is destructively cleaved and pierced to expose the signal line end, then the probe can contact the signal line for inspection, but significant time is required for the inspection process
Solution Approach 1:
The test structure is pre-integrated into the display panel during manufacturing, with test electrodes positioned at specific locations. This preliminary preparation eliminates the need for destructive substrate cleaving during inspection, as the probe can directly contact the pre-positioned test electrodes through openings in the planar layer.
3Measurement precision
If destructive cleaving and piercing of the substrate is performed, then the signal line end can be exposed for probing, but the inspection location is restricted to non-display regions which affects display consistency
Solution Approach 1:
The test structure is designed to be integrated within the display region itself, allowing the same area to serve both display functions and testing functions. The test electrodes are positioned such that they can be accessed through the planar layer without creating separate non-display regions, enabling dual use of the display area.
4Manufacturing precision
If a test structure is integrated in the display region, then imaging quality is maintained, but the test electrodes must be electrically insulated from signal lines before testing
Solution Approach 1:
The electrical connection state between the test electrode and signal line is dynamic rather than fixed. Before testing, the insulation layer maintains electrical isolation. During testing, the insulation layer is removed or breached to establish electrical connection. This dynamic state change allows the structure to serve both display and testing functions without permanent complexity.
Data Source
AI summary
A test structure of a display panel is provided. The test structure is within a buffer display region which is between a display region and a non-display region of the display panel and includes a substrate, at least one signal line on the substrate, an insulation layer covering the signal line, a planar layer on the insulation layer, and an electrode layer on the planar layer. The planar layer has at least one opening exposing a portion of the insulation layer. The electrode layer has a display electrode portion on the planar layer, at least one test electrode portion connecting the insulation layer via the opening and electrically insulated from the signal line, and at least one ring-shaped trench surrounding the test electrode portion and exposing a portion of the planar layer. The display electrode portion surrounds the ring-shaped trench and is electrically insulated from the test electrode portion.