Planarization Layer Trenches for LCD Moisture Barrier
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Solution Overview
Problem
Moisture penetration through the planarization layer in LCD panels, which leads to current leakage and failure of TFTs, compromising the reliability of display panels, especially under high-temperature and high-humidity conditions.
Innovation Solution
A trench is formed in the planarization layer on the non-display area of the LCD panel, with a rougher bottom than side, acting as a moisture barrier to prevent moisture from entering the display area, and additional trenches can be formed under the sealant to enhance adhesion and further prevent moisture ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a planarization layer made of organic materials is used to cover the TFTs, scan lines and data lines, then the surface is completely covered and planarized, but the layer has poor ability to resist moisture allowing moisture to penetrate into the display area
Solution Approach 1:
The planarization layer is segmented by forming trenches that divide it into separate regions. These trenches create a discontinuous structure that blocks moisture penetration paths while maintaining the planarization function in the display area.
Solution Approach 2:
The trench structure acts as an intermediary barrier between the moisture environment and the TFT components. By introducing this intermediate structure, moisture is prevented from reaching the sensitive electronic components underneath.
2Reliability
If the planarization layer is made completely flat and continuous, then the TFTs and conductors are fully covered, but moisture can still penetrate through the organic material layer
Solution Approach 1:
The continuous planarization layer is segmented by introducing trenches that create discontinuities. This segmentation maintains coverage of TFTs in the display area while creating moisture barrier regions in the non-display area where trenches are formed.
Solution Approach 2:
Different regions of the planarization layer have different structures: the display area maintains a continuous planarized surface for TFT coverage, while the non-display area contains trenches to provide enhanced moisture resistance. This local differentiation resolves the contradiction between coverage and moisture protection.
3Reliability
If additional trenches are formed under the sealant, then adhesion is enhanced and moisture prevention is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The trench structure is segmented into different locations: some trenches are formed in the planarization layer, and additional trenches are formed under the sealant. This segmentation allows targeted moisture barrier implementation where most needed while managing manufacturing complexity.
Solution Approach 2:
Trenches are formed in advance during the manufacturing process, specifically in the non-display area and under the sealant, to pre-establish moisture barrier paths before final assembly. This preliminary action prevents moisture issues without requiring complex post-processing.
Data Source
AI summary
A display panel is provided. The display panel includes a first substrate having a display area and a non-display area. A sealant is disposed on the first substrate and on the non-display area. A planarization layer is disposed on the first substrate. The planarization layer has a first trench formed therein on the non-display area. The first trench has a bottom and a side adjacent to the bottom. The bottom has a roughness that is greater than the roughness of the side.