OLED Cathode Contact via Passivation Hole
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Solution Overview
Problem
The top emission type OLED devices require a reverse-tapered partition to connect the cathode electrode with the auxiliary electrode, which is complex to form and prone to collapse or peeling, leading to difficulties in electrical connection.
Innovation Solution
A method that eliminates the need for a reverse-tapered partition by using a contact hole in the passivation layer to directly connect the cathode electrode with the auxiliary electrode, facilitating electrical contact without the need for a reverse-tapered structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reverse-tapered partition is provided to connect the cathode electrode with the auxiliary electrode, then electrical connection is achieved, but the manufacturing process becomes complex and the partition is prone to collapse or peeling
Solution Approach 1:
The invention extracts and eliminates the reverse-tapered partition structure from the device. Instead of using a complex partition structure to prevent organic emitting layer deposition, the patent uses a planar partition that extends to the auxiliary electrode, simplifying the manufacturing process while maintaining reliable electrical connection between the cathode and auxiliary electrodes through the contact hole structure.
Solution Approach 2:
The invention segments the connection function into two separate components: the planar partition structure that defines the pixel region and prevents organic emitting layer deposition, and the contact hole structure that provides electrical connection. This segmentation allows each component to perform its function independently without the complexity of a reverse-tapered partition.
2Manufacturing precision
If a reverse-tapered partition is used to prevent organic emitting layer deposition, then the partition serves as an eave, but the structure is difficult to form with desired shape and prone to collapse
Solution Approach 1:
The invention removes the reverse-tapered partition structure entirely and replaces it with a planar partition that extends to the auxiliary electrode. This eliminates the need for complex PEB processes to form the reverse-tapered shape, making the manufacturing process easier while maintaining precise control over the partition geometry through standard lithography and deposition processes.
3Productivity
If the cathode electrode is formed by sputtering process with inferior straightness, then the cathode electrode may be deposited in the gap space, but electrical connection between cathode and auxiliary electrode becomes difficult
Solution Approach 1:
The invention uses the planar partition structure as an intermediary element that extends to the auxiliary electrode. This partition structure serves as a physical barrier that guides the cathode electrode deposition, ensuring that even with inferior straightness characteristics of sputtering process, the cathode electrode can still achieve reliable electrical connection with the auxiliary electrode through the contact hole without being blocked by a reverse-tapered partition.
Data Source
AI summary
Disclosed is an organic light emitting display device that may include a substrate having an active area and a pad area, a passivation layer provided on the active area of the substrate, an anode electrode provided on the passivation layer, a bank layer for defining a pixel region on the anode electrode, an organic emitting layer provided on the bank layer and connected with the anode electrode, a cathode electrode provided on the organic emitting layer, and an auxiliary electrode electrically connected with the cathode electrode and provided under the passivation layer, wherein a contact hole for exposing the auxiliary electrode is provided in the passivation layer, the auxiliary electrode includes a lower auxiliary electrode and an upper auxiliary electrode, and the cathode electrode is in contact with an upper surface of the lower auxiliary electrode via the contact hole.