Flexible Display Device Trench Segmentation Stress Management
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Solution Overview
Problem
Flexible display devices face reliability issues due to stress on emission regions when deformed, leading to potential display defects from peeling at interfaces with differing film hardness and thickness.
Innovation Solution
The formation of trenches in the base material and sealing film in non-emission regions allows selective deformation of these areas, minimizing stress on emission regions and enhancing the display device's flexibility and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the base material and sealing film are made flexible to enable bending, then the display device can be deformed, but stress concentrates on the emission regions causing peeling and display defects
Solution Approach 1:
The base material is divided into emission regions and non-emission regions, with trenches formed in the non-emission regions. This segmentation allows different parts of the base material to have different functions: emission regions maintain structural integrity while non-emission regions with trenches allow controlled deformation, solving the contradiction between flexibility and display quality.
Solution Approach 2:
The sealing film structure is made non-uniform by forming trenches in non-emission regions while maintaining intact structure in emission regions. This local quality differentiation enables the sealing film to provide both protection for emission regions and flexibility through deformation in non-emission regions, resolving the contradiction between reliability and adaptability.
2Reliability
If the film thickness is increased to improve sealing, then sealing performance improves, but stress during deformation increases causing peeling at interfaces
Solution Approach 1:
The sealing film is segmented into regions with different thicknesses: thicker in emission regions for sealing and protection, thinner in non-emission regions with trenches to reduce stress during deformation. This segmentation resolves the contradiction between sealing performance and peeling resistance.
Solution Approach 2:
The film thickness parameter is changed spatially across different regions of the sealing film and base material. By varying thickness from uniform to non-uniform (thicker in emission regions, thinner in non-emission regions), the invention achieves both good sealing performance and reduced deformation stress.
3Ease of manufacture
If uniform film structure is used across the entire display, then manufacturing is simplified, but deformation causes stress distribution leading to peeling
Solution Approach 1:
The uniform film structure is segmented into emission regions and non-emission regions with different characteristics. Trenches are formed only in non-emission regions, creating a non-uniform structure that improves interface bonding during deformation while maintaining relative manufacturing simplicity through selective processing.
Data Source
AI summary
Provided is a display device including: a base material; a plurality of light-emitting elements located over a first surface of the base material and having an emission region; and a first trench located over a second surface of the base and overlapping with a non-emission region sandwiched between the emission regions of two adjacent light-emitting elements selected from the plurality of light-emitting elements. Alternatively, the display device includes: a base material; a plurality of pixels located over a first surface of the base material and having a light-emitting element; a first trench located over a second surface of the base material and overlapping with a region sandwiched between two adjacent pixels selected from the plurality of pixels; and a ridge located over the first surface of the base material, overlapping with the first trench, and consisting of the base material.