Patterned Planarization Layer for LCD Substrate Bonding
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Solution Overview
Problem
Conventional liquid crystal display panels experience poor bonding between substrates due to weak adhesion between the planarization layer and metal or inorganic materials, leading to peeling issues and reduced yield.
Innovation Solution
A patterned planarization layer with loop-shaped or L-shaped openings is designed on the substrate, increasing the contact area between the seal and the insulating and metal layers, and optionally a passivation layer is used to enhance adhesion and prevent corrosion, thereby improving the bonding force between substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a blanket planarization layer is formed over the array substrate to cover TFTs and metal lines, then the planarization is achieved, but poor adhesion between the planarization layer and metal/inorganic materials causes peeling and reduces bonding strength
Solution Approach 1:
The planarization layer is patterned with openings (through-holes or recesses) that segment the continuous layer into distinct regions. This segmentation allows the seal to directly contact the metal lines and inorganic materials in specific areas, creating localized bonding zones that prevent peeling while maintaining overall planarization in the display area.
Solution Approach 2:
The planarization layer has different properties in different regions: in the display area, it provides complete planarization coverage, while in the peripheral area, it has openings that expose the underlying metal and inorganic layers. This local variation in structure allows simultaneous achievement of planarization quality and bonding reliability in different zones.
2Reliability
If the planarization layer is made thinner to reduce peeling risk, then adhesion improvement is achieved, but insufficient planarization coverage leads to poor bonding between substrates
Solution Approach 1:
Rather than reducing the overall thickness of the planarization layer, the invention segments it with openings that expose the underlying layers only in peripheral areas. This maintains adequate planarization coverage in the display area while creating localized regions where the seal can directly bond to metal and inorganic materials for improved adhesion.
Solution Approach 2:
The seal acts as an intermediary element that bridges the planarization layer and the underlying metal/inorganic materials. By positioning the seal to contact both the planarization layer and the exposed metal lines through the openings, it creates a multi-layer bonding structure that enhances overall adhesion without compromising planarization coverage.
3Reliability
If the seal is positioned to directly contact metal lines for improved bonding, then substrate bonding strength is enhanced, but the planarization layer cannot provide adequate coverage and protection
Solution Approach 1:
The planarization layer is segmented with openings positioned in the peripheral area where the seal contacts the metal lines. This segmentation allows the seal to directly contact the metal lines for enhanced bonding strength while the planarization layer maintains coverage and protection in the display area and other peripheral regions.
Solution Approach 2:
The solution moves from a two-dimensional coverage problem to a three-dimensional structured approach. The planarization layer with openings creates vertical differentiation, allowing the seal to contact multiple layers (planarization layer, metal lines, and inorganic materials) at different depths, thereby achieving both coverage and direct bonding simultaneously.
Data Source
AI summary
A system for displaying images including a display panel is provided. The display panel has a display area and a peripheral area. The display panel includes a metal layer disposed on a first substrate. A second substrate is disposed opposite to the first substrate. A seal is disposed at the peripheral area and between the first and the second substrates and at the peripheral area. A patterned planarization layer is disposed on the first substrate, including an opening and two sidewalls, wherein the opening is located between the two sidewalls and corresponding to the peripheral area. A passivation layer is disposed between the seal and the first substrate, and wherein a portion of the seal is disposed between the two sidewalls of the patterned planarization layer.