Display Device Contact Hole Light Emission Uniformity
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Solution Overview
Problem
In display devices, the inclined face of contact holes causes the light-emitting layer to thin at the top due to gravity, leading to uneven light emission as the electric field concentrates, resulting in overcurrent and light emission unevenness.
Innovation Solution
A display device design featuring an organic insulating film with a first contact hole and a first pixel electrode, where a first light-emitting layer is formed on the film and a second light-emitting layer overlaps the first at least on the inclined face of the contact hole, with a common electrode corresponding to the pixel electrode, and the method involves forming these layers using a quantum dot photoresist to mitigate electric field concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light-emitting layer is applied and formed on the organic insulating film, then the display device can emit light, but the film thickness near the top of the inclined face of the contact hole is reduced due to gravity, causing electric field concentration and light emission unevenness
Solution Approach 1:
The patent introduces a second light-emitting layer that overlaps the first light-emitting layer at least in the inclined face region of the contact hole. This multi-layer approach compensates for the thickness reduction at the top of the inclined face by adding material from another dimension (vertical stacking), thereby restoring uniformity in the overall light-emitting structure without changing the fundamental single-layer formation process.
Solution Approach 2:
The patent applies different structural configurations to different regions: the first light-emitting layer covers the pixel electrode broadly, while the second light-emitting layer is specifically positioned to overlap at least in the inclined face region of the contact hole. This localized addition of the second layer addresses the specific problem area (top of inclined face) without unnecessarily complicating the entire structure.
2Length of stationary object
If the film thickness around the top of the light-emitting layer is thin, then the distance between the pixel electrode and the common electrode is shortened, but this causes electric field concentration and overcurrent, resulting in light emission unevenness
Solution Approach 1:
By stacking a second light-emitting layer over the first light-emitting layer, particularly in the inclined face region, the patent effectively increases the distance between the pixel electrode and common electrode in critical areas where the first layer alone is too thin. This vertical stacking approach maintains reliable current distribution without requiring a complete redesign of the electrode spacing.
Solution Approach 2:
The patent changes the structural parameter of the light-emitting layer from a single layer to multiple overlapping layers. This parameter change (from one layer to two or more layers) fundamentally alters the electrical characteristics by increasing the effective insulation distance and distributing the electric field more evenly, thereby preventing overcurrent and light emission unevenness.
Data Source
AI summary
A device includes an organic insulating film having a contact hole in which an inclined face is formed, a pixel electrode formed along an inclined face of the contact hole and the organic insulating film, an intra-pixel wiring line coupling the pixel electrode to a TFT within the contact hole, a light-emitting layer formed on the organic insulating film to cover the pixel electrode, a light-emitting layer formed to overlap the light-emitting layer at least in the inclined face of the contact hole, and a common electrode formed on the light-emitting layer correspondingly to the pixel electrode.