Display Device Test-Line Extraction for Narrow-Bezel Panels
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Solution Overview
Problem
The presence of test pads on display panels after manufacturing complicates the manufacturing process, restricts narrow bezel design, and increases the risk of damage to main lines and panels during etching operations.
Innovation Solution
A manufacturing method for display devices that includes a structure with a first lower etching stopper layer between the substrate and test line, a back coating film, and a multi-etching stopper layer configuration to facilitate cutting and reduce damage, ensuring test pads are not present on the final substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If test pads are placed inside the display panel during manufacturing, then the test process can be performed, but the manufacturing process becomes complicated and test pads remain on the substrate after manufacturing
Solution Approach 1:
The patent extracts the test pad from the final substrate by introducing a test pad substrate that is separately removed after testing. The test pad is temporarily placed on the test pad substrate during manufacturing and testing, then the test pad substrate is removed, leaving no test pad on the final display panel substrate.
Solution Approach 2:
The patent segments the test pad structure from the main substrate by introducing a separate test pad substrate. This allows the test pad to be independently positioned, tested, and removed, separating the testing function from the final display panel structure.
2Ease of manufacture
If test pads are disposed inside the display panel, then testing is enabled, but narrow bezel design is restricted
Solution Approach 1:
The test pad is extracted from the final display panel structure and placed on a separate test pad substrate that is removed after testing. This eliminates the need for test pads to remain on the substrate, enabling narrower bezel designs.
3Ease of manufacture
If etching operations are performed during manufacturing, then cutting can be facilitated, but main lines and panels may be damaged
Solution Approach 1:
The patent introduces a lower etching stopper layer as an intermediary protective barrier between the etching process and the main lines. This stopper layer absorbs the etching action, preventing direct damage to the underlying signal lines and display panel structure during cutting operations.
Solution Approach 2:
The lower etching stopper layer is deposited beforehand to cushion against the etching process. This protective layer is placed in advance to prevent potential damage to main lines during subsequent etching and cutting operations.
4Ease of manufacture
If test pads remain on the substrate after manufacturing, then testing was possible, but the final product has restricted design flexibility
Solution Approach 1:
The test pad is extracted from the final substrate through the use of a removable test pad substrate. After testing, the test pad substrate is completely removed, leaving the display panel ready for various design configurations without constraints from remaining test pads.
Data Source
AI summary
A display device may include a substrate including a display area and non-display area, a signal line disposed in the display area of the substrate, a test line disposed in the non-display area and connected to the signal line, and a first lower etching stopper layer disposed between the substrate and the test line. A rear surface edge of the substrate may be located further inside than an outer side edge of the first lower etching stopper layer. An end portion of the test line may include a portion that is located further outside than the rear surface edge of the substrate and does not overlap the substrate.