Top-Emission OLED Wiring via Spacer and Black Matrix
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Solution Overview
Problem
Top-emission type organic electroluminescence display devices face a trade-off between high light transmittance and conductivity, as increasing the thickness of transparent oxide semiconductor films to reduce sheet resistance decreases transmittance, and the use of metal thin films for conductivity interferes with light interference and requires precise mask manufacturing.
Innovation Solution
The device incorporates a bank surrounding pixel electrodes, a common electrode with light transmittance extending to the bank, a black matrix layer overlapping the bank, and wiring on the black matrix layer with a convex portion electrically connected to the common electrode, allowing for high conductivity without interfering with light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of transparent oxide semiconductor film is increased to reduce sheet resistance, then conductivity is improved, but light transmittance is reduced
Solution Approach 1:
The negative electrode is segmented into two separate layers: a transparent oxide semiconductor film (for light transmittance) and a metal thin film (for conductivity). This segmentation allows each layer to optimize its function independently, resolving the trade-off between transmittance and conductivity
Solution Approach 2:
The negative electrode uses a composite structure combining transparent oxide semiconductor material and metal material. This composite approach integrates the advantages of both materials: the oxide semiconductor provides high light transmittance while the metal provides high conductivity
2Reliability
If a metal thin film having high conductivity is used, then conductivity is improved, but light interference effect increases making it difficult to adjust luminescent color
Solution Approach 1:
The metal thin film is selectively applied only in the non-emission region (bank area) rather than covering the entire pixel electrode. This local application ensures high conductivity where needed while preventing light interference in the emission region, enabling proper luminescent color adjustment
3Reliability
If a metal film having high conductivity is formed in a non-emission region, then conductivity is improved without reducing pixel aperture, but film formation accuracy requirement increases making production application difficult
Solution Approach 1:
A resin layer is introduced as an intermediary between the pixel electrode and the metal thin film. The metal film is formed on the resin layer in the bank area, which simplifies the film formation process and reduces accuracy requirements compared to direct formation on the pixel electrode structure
Data Source
AI summary
Provided is an organic electroluminescence display device. The organic electroluminescence display device includes a bank that is provided so as to surround a central portion of a pixel electrode, an organic electroluminescence layer that is provided on the pixel electrode, a common electrode that is formed so as to extend from the organic electroluminescence layer to the bank, a color filter layer that overlaps the organic electro luminescence layer, a black matrix layer that overlaps the bank, a spacer that is provided on the black matrix layer, and a wiring that is provided on the black matrix layer so as to be placed on the spacer. The black matrix layer is disposed on the bank through the spacer. A convex portion is formed by the wiring being placed on the spacer, and the convex portion is electrically connected to the common electrode above the bank.