Bending Display Non-Display Area Stress Reduction
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Solution Overview
Problem
Display devices with expanded display areas by bending substrates face stress-related damage and durability issues due to weak curvature points, particularly at inorganic layers.
Innovation Solution
A display device design featuring a non-display area with a curvature that lacks light-emitting elements and encapsulation layers, incorporating organic protective patterns and compensation layers to reduce stress, and placing signal wiring, power bus wiring, and driving circuits in the non-display area to minimize the bezel and enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the display area is expanded by bending the substrate, then the display area is increased, but stress damage and durability decrease
Solution Approach 1:
The display device is divided into a first display area, a second display area, and a non-display area. The non-display area serves as a bending area that connects the two display areas, allowing the substrate to bend without compromising the display areas. This segmentation isolates the stress to a dedicated region, preventing damage to the functional display areas while maintaining durability.
Solution Approach 2:
The non-display area is specifically designed with different properties than the display areas. It lacks light-emitting elements and encapsulation layers, making it more flexible and suitable for bending. This local differentiation allows the substrate to bend in the non-display area without compromising the structural integrity and durability of the display areas.
2Reliability
If encapsulation layers are placed in the bending area, then light-emitting elements are protected, but curvature stress increases and reliability decreases
Solution Approach 1:
The encapsulation layers are extracted from the bending area (non-display area) and placed only in the display areas. This removal eliminates the source of curvature stress that would otherwise be generated by the encapsulation layers during bending. The light-emitting elements in the display areas remain protected by encapsulation layers, while the bending area remains free of these stress-inducing structures.
3Ease of operation
If signal wiring and other components are placed in the display area, then connectivity is achieved, but the bezel area increases
Solution Approach 1:
Signal wiring, power bus wiring, and driving circuits are relocated from the traditional display area to the non-display area (bending area). This spatial reorganization utilizes the available space in the bending region, allowing connectivity components to be positioned without increasing the visible display area or bezel size. The wiring extends through the non-display area, maintaining electrical connectivity while optimizing the overall device footprint.
Data Source
AI summary
A display device includes a first display area, a second display area and a non-display area between the first display area and the second display area and extending in a first direction, at least a portion of the non-display area having a bending area connecting the first display area to the second display area, the display device comprising: light-emitting elements on a base substrate in the first display area and in the second display area; a first encapsulation layer covering light-emitting elements in the first display area; a second encapsulation layer covering light-emitting elements in the second display area; a signal wiring crossing the non-display area and extending in a second direction; and an upper compensation layer in the non-display area and filling a gap between the first encapsulation layer and the second encapsulation layer.