Flexible Display Support Film Indent Pattern for Stress Relief
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Solution Overview
Problem
Display devices with flexible substrates and bending portions are prone to electrical wiring disconnection due to concentrated bending stress, which can lead to functional failures under impact.
Innovation Solution
The implementation of a display device configuration that includes a flexible substrate with flat and bending portions, supported by support films with indent patterns and a bonding layer, along with a touch printed circuit board and bending stress relieving layers, to distribute and alleviate bending stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible substrate with bending portion is used to enable device flexibility, then adaptability is improved, but bending stress concentration occurs leading to wiring disconnection
Solution Approach 1:
The support film is designed with a local indentation at the bending portion, creating a region with different mechanical properties. This indentation reduces the local thickness and flexibility of the support film at the bending area, thereby reducing bending stress concentration on the electrical wiring while maintaining the overall structural integrity and flexibility of the display device.
2Strength
If support films are disposed to overlap flat portions to provide structural support, then strength is improved, but bending stress concentrates at the contact region between support film end and display panel
Solution Approach 1:
The support film features a localized indentation at the bending portion, creating a thickness variation that reduces bending stress concentration. The indentation is positioned at the end portion of the support film where it contacts the display panel, allowing the rest of the support film to maintain full thickness and structural strength while the indented region provides stress relief during bending.
3Area of stationary object
If the support film extends fully to the bending portion to maximize coverage, then protective coverage is improved, but stress concentration on electrical wiring increases
Solution Approach 1:
Rather than reducing overall coverage, the support film maintains full extension to the bending portion but incorporates a localized indentation at the bending area. This indentation creates a thickness reduction specifically at the stress concentration zone, allowing the support film to cover the entire required area while providing stress relief to the electrical wiring at the critical bending region.
Data Source
AI summary
A display device includes a display panel having a display surface, the flexible substrate including a first flat portion, a second flat portion disposed to overlap the first flat portion in a thickness direction of the display device, and a bending portion between the first flat portion and the second flat portion; a touch panel disposed on the display panel, and including a pad side portion; a touch printed circuit board including a first attachment portion attached to a surface of the pad side portion; and a first support film disposed to overlap the first flat portion, and a second support film disposed to overlap the second flat portion, wherein the first support film includes a first indent pattern indented inwardly of the bending portion and from a remaining portion of the first support film.