OLED Encapsulation Block Height Layout Against Mask Scratch Defects
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Solution Overview
Problem
Flexible OLED displays face defects in thin film encapsulation due to uneven surfaces caused by mask scratches, leading to reduced useful lifetime and moisture permeation.
Innovation Solution
A display device design featuring block members with varying heights and irregular surfaces, formed using a half tone slit mask, to prevent encapsulation layer cuts and ensure effective moisture blocking, comprising a substrate with display and peripheral regions, and encapsulation layers of inorganic and organic materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mask is placed on the block member to form display structures, then the display structures can be formed, but the upper surface of the block member can be scratched leading to encapsulation defects
Solution Approach 1:
A planarization layer is formed on the block member before the mask placement step. This preliminary action creates a flat protective surface that prevents mask scratches from reaching the block member's upper surface, thereby preventing encapsulation layer defects while still allowing the mask to function properly for forming display structures
Solution Approach 2:
The planarization layer acts as an intermediary protective layer between the mask and the block member. It absorbs the mechanical stress and contact from the mask, preventing direct contact and scratching of the block member's upper surface, thus protecting the encapsulation layer integrity
2Ease of operation
If the block member has an uneven surface, then it can support the mask structure, but the thin film encapsulation becomes defective due to the uneven surface
Solution Approach 1:
The planarization layer is formed in advance on the uneven block member surface, creating a flat upper surface before the encapsulation process. This allows the mask to be supported by the block member's structural form while the planarization layer provides a defect-free surface for high-quality thin film encapsulation
Solution Approach 2:
The block member structure is functionally segmented into two parts: the main body that provides structural support and mask positioning, and the planarization layer that provides a flat surface for encapsulation. This segmentation allows each part to fulfill its specific function without compromising the other
Data Source
AI summary
A display device and a method of manufacturing the display device are disclosed. In one aspect, the display device includes a substrate including a display region and a peripheral region. A first block member is in the peripheral region and surrounding display structures, the first block member having a first height. A second block member is spaced apart from the first block member in a first direction extending from the display region to the peripheral region, the second block member surrounding the first block member, the second block member having a second height that is greater than the first height. A first encapsulation layer is over the display structures, the first block member, and the second block member. A second encapsulation layer is over the first encapsulation layer, the second encapsulation layer overlapping at least a portion of the first block member in the depth dimension of the display device.