Stretchable Display Stepped Planarization for Precise LED Transfer
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Solution Overview
Problem
The manufacturing of stretchable display devices is hindered by high consumption of anisotropic conductive film, increased costs, and the risk of electrical short circuits due to misalignment during the transfer process of light-emitting elements.
Innovation Solution
A stretchable display device design featuring a base substrate with rigid and soft portions, a planarization layer of varying heights, and a method of manufacturing that includes forming stretchable lines and auxiliary light-emitting elements to reduce anisotropic conductive film usage and prevent electrical short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anisotropic conductive film is transferred to the entire rigid portion, then light-emitting elements can be electrically connected, but consumption of anisotropic conductive film increases and manufacturing costs increase
Solution Approach 1:
The patent applies local quality by creating a stepped planarization layer structure where different regions have different heights. The first portion (higher) receives anisotropic conductive film for electrical connection, while the second portion (lower) does not. This localized approach ensures electrical connection reliability only where needed, reducing overall film consumption and manufacturing costs.
2Reliability
If anisotropic conductive film is transferred to the entire rigid portion, then light-emitting elements can be fixed, but misalignment occurs during transfer process
Solution Approach 1:
The stepped planarization layer creates distinct height levels that serve as precise positioning references. The higher first portion provides a localized transfer area for light-emitting elements, while the lower second portion acts as a reference boundary. This height differential improves alignment precision during the transfer process, preventing misalignment between light-emitting elements and underlying structures.
3Productivity
If light-emitting element is misaligned on anisotropic conductive film, then transfer process can be completed, but electrical short circuit occurs between misaligned element and signal line
Solution Approach 1:
The patent implements beforehand cushioning by designing a stepped planarization layer structure where the lower second portion extends beyond the first portion. This lower region acts as a protective buffer zone that prevents misaligned light-emitting elements from contacting signal lines and causing short circuits. The height differential provides a safety margin that compensates for potential alignment errors, maintaining electrical insulation reliability even when transfer efficiency is prioritized.
Data Source
AI summary
A stretchable display device includes a base substrate having a rigid portion and a soft portion; a stretchable line provided in the soft portion over the base substrate; a planarization layer provided in the rigid portion over the base substrate and having a first portion and a second portion of different heights; a light-emitting element over the first portion of the planarization layer; and an auxiliary light-emitting element over the second portion of the planarization layer, wherein a first height of the first portion of the planarization layer from the base substrate is greater than a second height of the second portion of the planarization layer from the base substrate.