Array Substrate Via Structure for Uniform Planarization
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Solution Overview
Problem
Large-sized OLED display devices face reliability issues due to the thickness of the color filter on the inorganic film, leading to a thinner planarization layer and increased risk of separation, which affects light transmittance and overall substrate reliability.
Innovation Solution
The array substrate design includes a first and second via structure, where the second via is wider than the first via and filled with the same color resist, eliminating the need for overlapping color resists, resulting in a uniform planarization layer thickness and improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the color filter is made thick to prevent light leakage, then light blocking performance is improved, but the planarization layer becomes thinner and separation risk increases
Solution Approach 1:
The patent divides the planarization function into two separate layers: a first planarization layer above the color filter and a second planarization layer above the first planarization layer. This segmentation allows the color filter to maintain its light-blocking function while the two planarization layers collectively provide sufficient thickness for mechanical support and prevent separation, thus resolving the contradiction between light leakage prevention and substrate reliability.
2Object-affected harmful factors
If overlapping color resists are used to prevent light leakage, then light blocking performance is improved, but the planarization layer thickness becomes non-uniform
Solution Approach 1:
The patent segments the planarization function into two distinct layers, allowing each layer to be optimized independently. The first planarization layer can be applied uniformly over the color filter without being constrained by the need to fill overlapping regions, while the second planarization layer provides additional planarization. This eliminates the thickness non-uniformity caused by overlapping color resists while maintaining light leakage prevention.
Solution Approach 2:
Instead of solving the light leakage problem in the horizontal plane through overlapping color resists, the patent transitions to a vertical solution by adding a second planarization layer above the first planarization layer. This dimensional shift allows light leakage prevention without compromising the uniformity of the planarization layer thickness.
3Ease of manufacture
If the planarization layer is made thin to maintain flexibility, then ease of manufacture is improved, but light transmittance decreases and separation risk increases
Solution Approach 1:
The patent segments the planarization structure into two layers with different functions: the first planarization layer provides mechanical support and prevents separation, while the second planarization layer optimizes the planar surface for subsequent manufacturing steps. This segmentation allows the overall structure to maintain sufficient thickness for reliability while keeping individual layers manageable for manufacturing, thus resolving the contradiction between ease of manufacture and light transmittance.
Data Source
AI summary
An array substrate is provided, including a base substrate, a semiconductor active layer, a gate electrode, a source electrode, and a drain electrode that are sequentially provided, and further including a first insulating layer, a second insulating layer, a third insulating layer, at least one first via, and at least one second via. Each first via penetrates through the third insulating layer, and in each pixel unit with plural chromatic color resists, each first via is between adjacent two chromatic color resists and filled by one of the adjacent two chromatic color resists. Each second via penetrates through the second insulating layer, the at least one second via is in one-to-one correspondence with the at least one first via, each second via is filled by a chromatic color resist having a same color as that of the chromatic color resist in the corresponding first via.