Display Device Insulating Layer Crack Prevention via Buffer Step Design
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Solution Overview
Problem
Existing light emitting diode (LED) display devices face defects due to foreign substances causing cracks in the insulating layer, leading to permeation of air or moisture and degradation of transistor characteristics.
Innovation Solution
A display device design where the first layer and signal wire are formed on the same substrate with different thicknesses, and a buffer layer is used to prevent cracking, with the first layer being thinner than the signal wire, and the buffer layer having a gentler step in the transistor area to facilitate easy removal of foreign substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the signal wire is made thick to ensure electrical performance, then electrical conductivity is improved, but the step difference with the first layer increases causing cracks in the insulating layer
Solution Approach 1:
The patent applies local quality by creating a gentler step in the buffer layer specifically in the transistor area where the signal wire and first layer meet. This localized modification allows the signal wire to maintain its thick structure for electrical performance while the buffer layer's gentler step prevents stress concentration that would cause cracks in the insulating layer.
2Strength
If a thick buffer layer is used to cover the step difference, then crack prevention is improved, but foreign substance removal becomes difficult
Solution Approach 1:
The buffer layer is designed with different step characteristics in different areas: a gentler step in the transistor area for crack prevention, and a steeper step in the signal wire area for easy foreign substance removal. This local differentiation allows the buffer layer to simultaneously achieve crack prevention and ease of manufacturing.
3Stability of the object's composition
If the first layer is made thin to reduce step difference, then insulating layer stability is improved, but electrical functionality may be compromised
Solution Approach 1:
The patent maintains the first layer's thin structure in the transistor area for insulating layer stability, while allowing the signal wire to be thick in the signal wire area for electrical functionality. The buffer layer's gentler step in the transistor area compensates for the thin first layer, ensuring both stability and functionality are achieved.
Data Source
AI summary
A display device according to an embodiment includes: a substrate including a signal wire area and a transistor area; a first layer disposed in the transistor area; a signal wire disposed in the signal wire area; a transistor disposed on the first layer; a first electrode electrically connected to the transistor; and an emission layer and a second electrode disposed on the first electrode, wherein the first layer and the signal wire are disposed on a same layer on the substrate, and the first layer and the signal wire have different thicknesses.