Micro LED Display Device with Mirror Layer for Enhanced Light Emission
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Solution Overview
Problem
Current display devices face challenges in achieving high emission efficiency due to limitations in the design and structure of their light-emitting diodes (LEDs), particularly in the arrangement and connectivity of electrodes and emission layers, which affect light emission and reflection efficiency.
Innovation Solution
The proposed display device incorporates a micro P-N diode emission layer with a specific arrangement of electrodes and reflective layers, including a mirror layer and a conductive layer, to enhance light emission and reflection efficiency, with the electrodes and reflective materials strategically positioned to improve light path and reduce thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional LED structure is used, then device simplicity is maintained, but light emission efficiency is insufficient
Solution Approach 1:
The emission layer is divided into multiple sub-layers including electron injection layer, electron transport layer, hole transport layer, and hole injection layer. Each layer is optimized for specific functions to improve overall light emission efficiency while maintaining manageable structural complexity through functional segmentation.
Solution Approach 2:
The patent introduces a mirror layer positioned at a specific distance below the emission layer, creating a vertical optical cavity structure. This dimensional arrangement enables constructive interference of light waves, significantly enhancing light emission efficiency without adding horizontal complexity to the device layout.
2Reliability
If thicker display device structure is used, then electrode connectivity is improved, but overall thickness increases
Solution Approach 1:
The source and drain electrodes are extended beyond the immediate emission layer area, creating dynamic connectivity paths that reach multiple functional layers. This extended electrode design ensures reliable electrical connection throughout the vertical stack while optimizing the distribution of conductive material to minimize overall thickness.
Solution Approach 2:
The patent introduces intermediate conductive layers and contact layers that mediate between the source/drain electrodes and the emission layer. These intermediary structures provide reliable electrical connectivity while maintaining compact vertical spacing, preventing direct thick connections and enabling thin-film integration.
3Illumination intensity
If mirror layer is added to improve reflectivity, then light emission efficiency increases, but device complexity increases
Solution Approach 1:
The mirror layer is positioned at a specific distance (d) below the emission layer, where d is optimized to create constructive interference for the emitted wavelength. By precisely controlling this parameter, the system achieves high reflection efficiency and enhanced light emission without requiring complex multi-layer optical coatings, maintaining relative structural simplicity.
4Reliability
If electrode extension is used to improve connectivity, then electrical connection is enhanced, but manufacturing complexity increases
Solution Approach 1:
The source and drain electrodes are merged with the extended contact structures in a single continuous conductive layer. This merging approach ensures reliable electrical connectivity across multiple functional layers while simplifying the manufacturing process by reducing the number of separate deposition and patterning steps required for multiple discrete electrodes.
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 configuration enhances light emission efficiency by optimizing the light path and reducing the overall thickness of the display device, while also simplifying the structure and improving reflectivity, leading to improved display performance.
Implementation Method 1
a mirror layer over the bank layer, where the mirror layer is arranged to overlap the thin film transistor in a vertical direction of the display substrate
Implementation Method 2
A light-emitting diode (LED) is a semiconductor device including a P-N junction diode. When a voltage is applied to the P-N diode of the LED in a forward direction, electrons recombine with holes in the P-N diode and energy generated by such a recombination is converted into light energy
Data Source
AI summary
A display device includes a display substrate; a thin film transistor over the display substrate; a bank layer covering the thin film transistor, where an opening is defined through the bank layer; an emission layer in the opening and including a micro p-n diode; a first electrode electrically connected between the thin film transistor and the emission layer; a second electrode over the emission layer; and a sealing layer covering the second electrode. The thin film transistor and the emission layer are adjacent to each other in a horizontal direction of the display substrate.