Optical Functional Layer Valleys for Foldable Display Wire Reliability
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Solution Overview
Problem
Existing display devices face challenges in reducing the width of the non-display area and overall thickness, particularly in flexible and foldable organic light-emitting display devices, where stress concentration on wires during bending can lead to disconnection and increased visible non-display area.
Innovation Solution
The display device incorporates a substrate with a bending area featuring a barrier rib layer, an input detection layer, and an optical functional layer with a second layer having a different refractive index, which extends to the peripheral area and includes valleys to reduce stress on wires, while maintaining a neutral plane, thereby minimizing the non-display area and thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the non-display area width is reduced to improve display area ratio, then the display area ratio is improved, but stress concentration on wires during bending increases causing disconnection
Solution Approach 1:
The bending area is divided into multiple segments along the bending axis, with valleys created at specific positions. This segmentation distributes the stress concentration points and prevents wire disconnection by creating stress relief zones between the display area and peripheral area.
Solution Approach 2:
The optical functional layer is designed with spatially varying thickness and refractive index characteristics. The first layer has a first refractive index while the second layer has a second refractive index different from the first layer, creating local optical quality variations that maintain neutral plane stability during bending while protecting wires.
2Length of stationary object
If the overall thickness is reduced to improve device profile, then the device thickness is reduced, but structural integrity during bending deteriorates
Solution Approach 1:
The optical functional layer comprises multiple layers with different refractive indices and mechanical properties. This composite structure provides both thinness and bending strength by combining materials with complementary properties, allowing the device to maintain structural integrity during bending while achieving reduced overall thickness.
Solution Approach 2:
The patent introduces vertical layering with varying thicknesses in the optical functional layer. The first layer and second layer have different thickness profiles, creating a three-dimensional stress distribution that enhances bending resistance while maintaining overall thinness. This dimensional approach allows stress management without increasing planar footprint.
3Reliability
If valleys are introduced to reduce stress on wires, then wire connection reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The stress relief function and optical function are merged into a single integrated optical functional layer structure. The valleys are formed as part of the optical functional layer's thickness variation rather than as separate structural elements, combining stress management and optical performance in one component to reduce overall device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces the visible non-display area and overall thickness by distributing stress and preventing wire disconnection, enhancing the flexibility and aesthetic appeal of the display device.
Implementation Method 1
an optical functional layer including a first layer that is disposed on the input detection layer and includes a first opening in an area corresponding to the display element, and a second layer that is disposed on the first layer and has a refractive index different from the first layer, wherein the first layer includes at least one valley located between the bending area and the driving circuit
Implementation Method 2
which extends to the peripheral area and includes valleys to reduce stress on wires, while maintaining a neutral plane
Implementation Method 3
a barrier rib layer arranged in the bending area
Data Source
AI summary
Provided is a display device including: a substrate including a display area and a peripheral area that includes a bending area disposed adjacent to the display area; a plurality of pixels arranged in the display area; a driving circuit arranged in the peripheral area; a barrier rib layer arranged in the bending area; an input detection layer disposed on the plurality of pixels; and an optical functional layer including a first layer that is disposed on the input detection layer and includes a first opening in an area corresponding to the plurality of pixels, and a second layer that is disposed on the first layer and having a refractive index different from the first layer, wherein the first layer includes at least one valley located between the bending area and the driving circuit.