OLED Pixel Electrode Fabrication Using Shadow Mask
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Solution Overview
Problem
The existing OLED fabrication processes involve strong acidic or basic chemicals that can form a metal oxide layer between the first and second pixel electrodes, leading to weakened adhesion and potential peeling-off of the Ag layer from the ITO layer due to oxidation, which affects the stability and performance of the organic light emitting diode.
Innovation Solution
The method involves forming a first pixel electrode, a pixel-defining layer with an opening, and second and third pixel electrodes within this opening using a shadow mask, thereby avoiding the exposure of the second pixel electrode to etching and cleaning chemicals, preventing the formation of a metal oxide layer and maintaining strong adhesion between electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If strong acidic or basic chemicals are used in etching and cleaning processes, then the etching and cleaning functions are achieved, but a metal oxide layer is formed between the first and second pixel electrodes, causing weakened adhesion and potential peeling-off
Solution Approach 1:
The harmful effect is eliminated by removing the second pixel electrode from the etching and cleaning processes entirely. The patent achieves this by forming the second pixel electrode after the etching and cleaning steps, so it never comes into contact with strong chemicals, thus preventing oxide layer formation while maintaining the necessary etching and cleaning functions for other structures
Solution Approach 2:
The patent performs protective actions in advance by forming the pixel-defining layer with openings that precisely expose only the required portions of the first pixel electrode before etching. This preliminary configuration ensures that subsequent etching and cleaning processes do not expose the second pixel electrode to chemicals, preventing adhesion problems before they can occur
2Productivity
If the second pixel electrode is exposed to etching and cleaning chemicals, then the manufacturing process is completed, but oxidation occurs forming a metal oxide layer that weakens adhesion between electrodes
Solution Approach 1:
The second pixel electrode is extracted from the sequence of operations that involve chemical exposure. By reordering the fabrication steps to form the second electrode after etching and cleaning are complete, the patent maintains full manufacturing functionality while eliminating the harmful chemical exposure that causes oxidation and adhesion loss
Solution Approach 2:
The pixel-defining layer serves as an intermediary structure that controls and limits chemical exposure. Its openings are precisely designed to expose only the necessary portions of the first pixel electrode while protecting the second pixel electrode from chemical contact, thus mediating between the need for etching/cleaning and the need to prevent oxidation
Data Source
AI summary
An Organic Light Emitting Display (OLED) and its method of fabrication, is capable of omitting a process of patterning a second pixel electrode by forming a first pixel electrode, forming a pixel-defining layer including an opening on the first pixel electrode, and forming the second pixel electrode and a third pixel electrode in the opening using a shadow mask as a mask. The OLED includes: a substrate; a first pixel electrode disposed on the substrate; a pixel-defining layer having an opening exposing a portion of the first pixel electrode; a second pixel electrode disposed on the first pixel electrode exposed by the opening of the pixel-defining layer and disposed in the opening of the pixel-defining layer; a third pixel electrode disposed on the second pixel electrode and disposed in the opening of the pixel-defining layer; an organic layer disposed on the third pixel electrode and including an emission layer; and an opposite electrode disposed on the organic layer.