Planarization Layer Design for Display Device Moisture Protection
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Solution Overview
Problem
Display devices face challenges in preventing moisture and oxygen permeation, leading to defects such as dark points, particularly due to the exposure of voltage lines during the etching process which can damage the thin film encapsulating layer.
Innovation Solution
A display device design featuring a planarization layer with a dividing region that covers the lateral sides of voltage lines in the non-display area, using a dam to prevent moisture and oxygen ingress, and a thin film encapsulating layer with alternating organic and inorganic layers to enhance sealing and prevent defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the voltage line is exposed in the non-display region during etching, then the manufacturing process is simpler, but the thin film encapsulating layer is damaged and moisture/oxygen permeation occurs
Solution Approach 1:
The planarization layer serves as an intermediary protective element that covers the voltage line in the non-display region. This mediator prevents direct exposure of the voltage line during etching while still allowing the etching process to proceed, thus protecting the thin film encapsulating layer from damage and preventing moisture and oxygen permeation without significantly complicating the manufacturing process.
2Reliability
If the planarization layer completely covers the voltage line, then the encapsulating layer is protected, but the voltage line cannot be properly connected and manufactured
Solution Approach 1:
The planarization layer is selectively positioned to cover only specific portions of the voltage line in the non-display region, while leaving other portions exposed. This local differentiation allows the encapsulating layer to be protected where needed while maintaining voltage line connectivity and manufacturability in other areas.
3Object-affected harmful factors
If the planarization layer is extended into the non-display region to cover voltage lines, then moisture and oxygen permeation is prevented, but the device complexity increases
Solution Approach 1:
The planarization layer is divided into multiple regions: a first planarization layer in the display region and a second planarization layer extending into the non-display region. This segmentation allows the protective function to be extended to cover voltage lines and prevent moisture/oxygen permeation while maintaining a relatively simple overall structure that is easy to manufacture.
Data Source
AI summary
A display device is disclosed. In one aspect, the device includes a substrate and a display unit disposed on the substrate and including a plurality of pixels each pixel including a thin film transistor, a display element electrically connected to the thin film transistor, and a planarization layer interposed between the thin film transistor and the display element. The display unit includes a display region and a non-display region surrounding the display region, wherein the non-display region includes a voltage line. The planarization layer comprises a central portion, an outer portion and a dividing region interposed between the central and outer portions, wherein the dividing region is located in the non-display region. The planarization layer covers at least a lateral side of the voltage line formed in the dividing region.