OLED Pixel Definition Layer Open Slot Reflective Cathode
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In high-resolution OLED displays, light interference from adjacent sub-pixels due to reflective cathodes in non-emitting regions leads to decreased color purity and color shift, affecting display quality.
Innovation Solution
An organic light emitting display panel design featuring open slots in the pixel definition layer with a reflective cathode only in the light emitting region, preventing light interference from adjacent sub-pixels by ensuring light transmission and absorption in non-emitting areas, and optionally incorporating a conductive layer and reflector for improved light utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a reflective cathode is used in the entire pixel region including non-emitting regions, then light extraction efficiency is improved, but color purity decreases and color shift occurs due to light interference from adjacent sub-pixels
Solution Approach 1:
The cathode is segmented into multiple independent regions, with reflective cathodes positioned only in light-emitting regions and non-reflective cathodes in non-emitting regions. This segmentation allows the reflective property to be applied selectively, improving light extraction where needed while preventing color interference in non-emitting areas.
Solution Approach 2:
Different regions of the cathode are assigned different optical properties: reflective in light-emitting regions to enhance light extraction, and non-reflective in non-emitting regions to prevent light interference. This local differentiation of cathode properties resolves the contradiction between overall light extraction efficiency and local color purity.
2Ease of manufacture
If the cathode extends into non-emitting regions, then manufacturing simplicity is maintained, but light interference from adjacent sub-pixels increases
Solution Approach 1:
The cathode structure is divided into distinct reflective and non-reflective regions, with clear boundaries aligned to pixel and sub-pixel structures. This segmentation prevents light from non-emitting regions from reflecting into adjacent sub-pixels while maintaining a relatively simple manufacturing process using standard OLED fabrication techniques.
3Manufacturing precision
If open slots are provided in the pixel definition layer with cathode only in light emitting region, then color purity is improved, but device complexity increases
Solution Approach 1:
The open slot structure nests the cathode within defined regions of the pixel definition layer. The pixel definition layer with its open slots provides a structural framework that automatically defines where the cathode should be positioned, integrating multiple functions (pixel definition, cathode positioning, light management) into a nested hierarchical structure that manages complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances color purity and reduces color shift by isolating light emission to intended regions, improving overall display quality by preventing unwanted light interference.
Implementation Method 1
the reflector is provided in the pixel definition layer and being used to reflect an incident light toward adjacent organic light emitting layer
Implementation Method 2
the cathode generally adopts a metal with high reflectivity such as aluminum, magnesium and silver
Data Source
AI summary
An organic light emitting display panel is provided, includes a substrate, a transparent anode, a pixel definition layer, an organic light emitting layer and a plurality of cathodes having reflective function provided on the substrate. A plurality of open slots is provided on the pixel definition layer. The anodes are provided on one end of the open slot adjacent to the substrate, the organic light emitting layer is packed in the open slot, the cathodes are provided on another side of the open slot away from the substrate. A method of manufacturing an organic light emitting display panel is also provided. The reflective cathode is made only in light emitting region, can prevent sub-pixels from light interference emitted from adjacent sub-pixels as well as increase color purity and improve color shift phenomenon in a bottom emission type device.