OLED Cathode Isolation Structure for Pixel Light Leakage
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Solution Overview
Problem
As the resolution of light emitting display panels increases, undesired light emission occurs due to lateral leakage current (LLC) between adjacent pixels, primarily caused by the light emitting layer and cathode in adjacent pixels.
Innovation Solution
A light emitting display apparatus is designed with a planarization layer, anodes, banks, and a cathode structure that includes boundary grooves and banks made of different materials, with an undercut isolating the boundary region cathode from the main cathode, reducing lateral leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the resolution of the light emitting display panel is increased, then the display quality is improved, but lateral leakage current occurs between adjacent pixels causing unwanted light emission
Solution Approach 1:
The patent divides the cathode into multiple separate cathode regions corresponding to different pixels, with insulating layers positioned between adjacent cathode regions. This segmentation prevents lateral leakage current from spreading between pixels while maintaining high resolution display quality.
Solution Approach 2:
The patent introduces insulating layers as intermediary elements between adjacent pixels. These insulating layers act as barriers that block lateral leakage current while allowing the light emitting layer to function properly, thus eliminating unwanted light emission between pixels.
2Object-generated harmful factors
If insulating layers are added to block lateral leakage current, then light leakage is reduced, but device complexity increases
Solution Approach 1:
The insulating layers serve multiple functions simultaneously: they block lateral leakage current, define pixel boundaries, and provide structural support. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent combines the insulating layer function with the existing cathode structure by positioning the insulating layers within the cathode region. This integration approach merges multiple functions into a single structural element, minimizing the increase in overall device complexity.
Data Source
AI summary
A light emitting display apparatus includes a planarization layer provided in a substrate, a plurality of anodes provided on the planarization layer, a bank including opening regions exposing the anodes, a light emitting layer provided on the plurality of anodes and the bank, and a cathode provided on the light emitting layer, the cathode including a boundary region cathode and a main cathode, wherein a boundary groove is at an outer portion of each of the plurality of anodes.