Micro LED Reflection Structure for Side-Light Loss Reduction
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Solution Overview
Problem
Micro LED displays face challenges in achieving high light efficiency due to the small size of micro LEDs, which makes it difficult to handle and mount them directly on a display panel, leading to potential light loss and reduced efficiency.
Innovation Solution
The development of a micro-scale light emitting device that includes a semiconductor stack with a distributed Bragg reflector insulation layer and a metal reflection layer, designed to improve light emission efficiency by minimizing light loss through the side surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If micro LEDs are made extremely small (200 μm or less, further 100 μm or less) to increase pixel density, then the display resolution is improved, but the light efficiency deteriorates due to increased light loss and difficulty in handling and mounting
Solution Approach 1:
The patent converts the harmful light loss at the side surfaces of micro LEDs into beneficial reflected light by applying a reflection layer. Instead of allowing light to escape uselessly from the sides, the reflection layer redirects this light toward the front surface, transforming energy loss into useful light output and improving overall light efficiency while maintaining small micro LED size for high resolution displays
Solution Approach 2:
The patent addresses light management by adding a vertical dimension solution (reflection layer on side surfaces) to compensate for the limitations of horizontal light emission in miniaturized LEDs. This dimensional approach allows light redirection from side surfaces without increasing the horizontal footprint of the micro LEDs, thereby maintaining high display resolution while improving light efficiency
2Measurement precision
If micro LEDs are made extremely small to increase pixel density, then the display resolution is improved, but the ease of manufacture deteriorates due to difficulty in handling and mounting
Solution Approach 1:
The patent applies the reflection layer and insulation layer to micro LEDs before final mounting on the display panel. This preliminary preparation of optical layers simplifies the subsequent mounting process by eliminating the need for complex alignment and positioning procedures, thereby improving ease of manufacture while maintaining the small size necessary for high display resolution
3Loss of energy
If a reflection layer is added to improve light efficiency, then light efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent designs the reflection layer to serve multiple functions simultaneously: it reflects light from side surfaces to improve light efficiency, provides electrical insulation to prevent short circuits, and maintains structural integrity of the micro LED. This multi-functionality reduces the need for separate components, thereby improving light efficiency without proportionally increasing device complexity
Solution Approach 2:
The patent combines the reflection layer and insulation layer into an integrated structure that performs both optical and electrical functions. By merging these functions into a single or closely integrated component, the patent achieves improved light efficiency while minimizing the increase in overall device 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 solution enhances the light efficiency of micro LED displays by effectively directing light outward, reducing internal losses, and enabling mass production of high-efficiency light emitting modules.
Implementation Method 1
the insulation layer includes a distributed Bragg reflector
Implementation Method 2
a metal reflection layer disposed on the insulation layer, and covering at least a portion of the side surface of the semiconductor stack
Data Source
AI summary
A light emitting device is a micro-scale light emitting device including a semiconductor stack, an insulation layer, and a metal reflection layer. The semiconductor stack includes a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer disposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer. The insulation layer covers upper and side surfaces of the semiconductor stack. The metal reflection layer is disposed on the insulation layer, and covers at least a portion of the side surface of the semiconductor stack. The insulation layer includes a distributed Bragg reflector.