Light Emitting Device With Projection Reflective Layer
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Solution Overview
Problem
Conventional light emitting devices have limitations in optical efficiency, which affects their performance and reliability, particularly in terms of side surface light extraction and overall light emission efficiency.
Innovation Solution
A light emitting device structure is developed, featuring a reflective layer with projection parts and a transparent supporting layer, which enhances side surface light extraction efficiency by altering the incidence angle of light emitted from the active layer, allowing light to be emitted both top and side surfaces, thereby improving light efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional light emitting device structure is used, then the device is simple to manufacture, but the light extraction efficiency is limited
Solution Approach 1:
The reflective layer is designed with projection parts that extend upward toward the light emitting structure, creating a three-dimensional structure instead of a flat layer. This dimensional change allows light to be extracted not only from the top surface but also from the side surfaces of the projection parts, thereby improving light extraction efficiency without complicating the manufacturing process
Solution Approach 2:
The reflective layer is segmented into multiple projection parts distributed across the substrate. Each projection part independently contributes to light extraction, and their distributed arrangement creates multiple light extraction pathways, improving overall efficiency while maintaining manufacturing simplicity through repetitive patterning
2Device complexity
If light is emitted only from the top surface, then the device structure is simple, but the light emission efficiency is limited
Solution Approach 1:
The invention transitions from two-dimensional top surface light emission to three-dimensional light emission by incorporating side surfaces of projection parts as additional light extraction interfaces. This enables light to emerge from multiple spatial dimensions (top and sides), significantly improving light emission efficiency while adding only moderate structural complexity
Solution Approach 2:
The projection parts serve multiple functions: they act as reflective surfaces, provide side surface light extraction pathways, and maintain structural support. This multi-functionality improves light emission efficiency without requiring separate components, thereby limiting the increase in device complexity
3Volume of moving object
If the reflective layer is placed directly under the light emitting structure, then the structure is compact, but the side surface light extraction is insufficient
Solution Approach 1:
The reflective layer is transformed from a flat two-dimensional layer into a three-dimensional structure with projection parts that have side surfaces. These side surfaces create new light extraction interfaces that were not present in the conventional flat structure, enabling side surface light extraction while maintaining compact device volume
Solution Approach 2:
The projection parts are strategically positioned and shaped to create localized regions of enhanced light extraction. The side surfaces of projection parts specifically target side surface light extraction needs, while the overall structure remains compact due to the localized nature of these features rather than requiring a complete structural expansion
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
The solution significantly enhances light extraction efficiency and stability by broadening the orientation angle of light emission, reducing light absorption, and improving the overall performance of the light emitting device.
Implementation Method 1
a reflective layer formed under the light emitting structure
Data Source
AI summary
A light emitting device includes a light emitting structure comprising a first conductivity type semiconductor layer, an active layer and a second conductivity type semiconductor layer; a reflective layer formed under the light emitting structure; and a transparent supporting layer formed between the light emitting structure and the reflective layer, to emit a light generated from the active layer; and a conductive layer formed under the reflective layer, to surround the reflective layer.