Non-conductive Reflective Films for Semiconductor Light Emitting Devices
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Solution Overview
Problem
Semiconductor light emitting devices face issues with light loss due to absorption by metal reflective films and poor current spreading, leading to reduced brightness and efficiency.
Innovation Solution
The use of non-conductive reflective films with multiple layers, including DBR and ODR structures, is implemented to minimize light absorption and enhance reflectance, along with extendable electrodes to prevent mechanical damage during handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If metal reflective films are used to reflect light from the active layer, then light reflectance is improved, but light absorption by the metal increases causing light loss
Solution Approach 1:
The patent introduces a non-conductive reflective film as an intermediary layer between the metal electrode and the active layer. This non-conductive film has high reflectance for light while being transparent to electrons, allowing light to be reflected back to the active layer without being absorbed by the metal, thus resolving the contradiction between achieving high reflectance and minimizing light loss
Solution Approach 2:
The reflective function is segmented into two separate components: a non-conductive reflective film for light reflection and a metal electrode for electrical conduction. This segmentation allows each component to perform its specific function optimally without the harmful interaction of light absorption by metal, thereby maintaining high reflectance while reducing light loss
2Loss of energy
If non-conductive reflective films are used to reduce light absorption, then light loss is reduced, but current spreading becomes poor
Solution Approach 1:
The patent merges the light reflection function and current spreading function into a single integrated non-conductive reflective film structure. This film simultaneously provides high light reflectance and facilitates electron transport, eliminating the need for separate metal layers and resolving the contradiction between reducing light loss and maintaining current spreading
3Reliability
If electrodes are extended to protect from mechanical damage, then device reliability is improved, but light loss may increase due to larger electrode area
Solution Approach 1:
The patent uses a thin non-conductive reflective film that extends across the device surface to provide mechanical protection and electrical functionality. This thin film structure provides the necessary mechanical strength and protection while maintaining optical transparency and reflectance properties, thus protecting the device without significantly increasing light loss
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 approach reduces light loss and improves brightness by minimizing absorption and optimizing current spreading, while also protecting the device from mechanical impacts during handling.
Implementation Method 1
a first non-conductive reflective film provided on the plurality of semiconductor layers to reflect light from the active layer
Implementation Method 2
has a first incident angle as the Brewster angle; has a second incident angle as the Brewster angle
Data Source
AI summary
Disclosed is a semiconductor light emitting device including: a plurality of semiconductor layers; a first non-conductive reflective film formed on the plurality of semiconductor layer to reflect light from the active layer, wherein the first non-conductive reflective film includes multiple layers and has a first incident angle as the Brewster angle; a second non-conductive reflective film formed on the first non-conductive reflective film to reflect light transmitted through the first non-conductive reflective film, wherein the second non-conductive reflective film includes multiple layers, with part of which being made of a different material from the first non-conductive reflective film, and has a second incident angle as the Brewster angle, different from the first incident angle; and an electrode electrically connected to one of the plurality of semiconductor layers.