Planarization Layer Shields Via Holes for Uniform PI Coating
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Solution Overview
Problem
The uniformity of PI coating on array substrates is difficult to control, particularly around the periphery, leading to defects due to non-uniform dispersion of the orientation solution, which affects the display device's performance.
Innovation Solution
A planarization layer is applied to the array substrate, extending to the non-display area and shielding via holes and metal wires, ensuring a uniform dispersion of the orientation solution and improving the orientation film's formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PI Inkjet coating is used on array substrate, then coating speed and production capacity are improved, but coating uniformity deteriorates due to non-uniform dispersion of PI liquid on metal layers in non-display area
Solution Approach 1:
A planarization layer is introduced as an intermediary between the metal layer and the orientation film. This planarization layer has a refractive index matching the liquid crystal material and covers the via holes in the non-display area, providing a uniform surface for PI liquid dispersion while maintaining high coating speed through inkjet coating process
Solution Approach 2:
The planarization layer is selectively applied to the non-display area where via holes are located, rather than covering the entire substrate. This localized approach addresses the specific problem of non-uniform PI liquid dispersion on metal surfaces without affecting the display area, maintaining both productivity and coating uniformity
2Reliability
If via holes with high density are formed in non-display area, then electrical connection is improved, but orientation solution dispersal uniformity deteriorates on the periphery of array substrate
Solution Approach 1:
The planarization layer serves as a mediator that covers the high-density via holes in the non-display area, creating a uniform surface that prevents the via holes from interfering with orientation solution dispersal, thereby maintaining both electrical connection reliability and orientation film quality
Solution Approach 2:
The planarization layer is formed in advance before the orientation film deposition, preliminarily addressing the surface non-uniformity caused by via holes. This preliminary action ensures that when the orientation solution is applied, the surface is already prepared for uniform dispersal
Data Source
AI summary
The present invention discloses an array substrate, a display panel and a display device. A planarization layer is covered on the array substrate, forms a planar plane on the array substrate and an orientation film is set on the planarization layer, the planarization layer extends to a non-display area of the array substrate, and the thickness thereof in the position where a via hole is formed in the non-display area on the array substrate is not less than the depth of the via hole. The present invention has the following beneficial effects: avoiding that an orientation solution is influenced by the via hole during formation of an orientation layer, thus the orientation solution disperses uniformly, the problem that defects occur on the periphery of the orientation film is well alleviated, the formation effect of the orientation film is improved, thereby the display effect of the display device is improved.