Reflective Pixel Structure for Higher-Efficiency Display Emission
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Solution Overview
Problem
Existing display devices face challenges in improving light output efficiency and reducing power consumption, particularly in forming a reflective layer and minimizing contact resistance of the common electrode.
Innovation Solution
A display device is designed with a planarization layer having an undercut shape, a light emitting element with a downwardly convex recess, and a reflective layer formed around the partition walls and light emitting elements, along with a common electrode in direct contact with the exposed semiconductor layer to reduce contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a reflective layer is formed to improve light output efficiency, then light output efficiency is improved, but device complexity increases
Solution Approach 1:
The reflective layer is segmented into multiple portions: a first reflective layer formed on the partition wall and a second reflective layer formed on the bottom surface. This segmentation allows each portion to serve specific functions - the first reflective layer redirects light from the partition wall area while the second reflective layer reflects light from the bottom surface, collectively improving light output efficiency without requiring a single complex reflective structure
Solution Approach 2:
Different regions of the device are assigned different reflective properties. The partition wall area receives a first reflective layer with specific optical characteristics, while the bottom surface receives a second reflective layer. This local differentiation optimizes light reflection in each specific region, improving overall light output efficiency while maintaining manageable device complexity through localized solutions
2Use of energy by moving object
If the common electrode is placed in direct contact with the semiconductor layer to reduce contact resistance, then power consumption is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The recess structure is formed in advance during the element fabrication process, creating a pre-positioned contact area on the semiconductor layer. The common electrode is then deposited to directly contact the recessed area, ensuring proper alignment and contact without requiring high-precision post-processing steps. This preliminary formation of the contact structure reduces manufacturing precision requirements while achieving low contact resistance
3Ease of manufacture
If the second planarization unit is positioned inside the pixel electrode to create an undercut shape, then ease of manufacture is improved, but manufacturing precision requirements increase
Solution Approach 1:
The undercut shape is created by positioning the second planarization unit at a different horizontal position relative to the pixel electrode, forming an overhang structure. This dimensional arrangement allows the planarization unit to be formed using standard photolithography and etching processes without requiring complex 3D shaping, improving ease of manufacture while the precise dimensional control achieves the desired undercut geometry
Data Source
AI summary
A display device includes a planarization layer including a first planarization unit on a substrate and a second planarization unit on the first planarization unit, a pixel electrode on the second planarization unit, an organic pattern layer on the pixel electrode, a light emitting element on the organic pattern layer and having a downwardly convex recess on a top surface thereof, a first partition wall on one surface of the first planarization unit and forming a space around the light emitting element, a via layer in the space around the light emitting element, a first reflective layer around a side of the first partition wall in the space around the light emitting element, on the first planarization unit, and around a side of the light emitting element, a side of the organic pattern layer, and a side of the pixel electrode.