Semiconductor Light Emitting Device With Wavelength Conversion
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Solution Overview
Problem
Semiconductor light emitting devices face challenges in improving light extraction efficiency due to electrical connection and optical loss issues related to substrates used in their manufacturing process.
Innovation Solution
A semiconductor light emitting device is designed with a light-transmissive support containing a wavelength conversion material, a semiconductor stack with conductivity-type layers and an active layer, a light-transmitting bonding layer, and a light blocking film to enhance light extraction efficiency by incorporating a wavelength conversion structure in a flip chip configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a substrate is used for epitaxial growth in the manufacturing process, then the semiconductor stack can be grown, but electrical connection and optical loss issues occur requiring substrate removal
Solution Approach 1:
The patent extracts the substrate from the final device structure by performing substrate removal after epitaxial growth. The growth substrate is completely removed to eliminate electrical connection issues and optical losses, leaving only the semiconductor stack supported by the lower cladding layer and distributed Bragg reflector structure.
Solution Approach 2:
The patent segments the support structure into multiple functional layers: a lower cladding layer providing mechanical support, and a distributed Bragg reflector structure providing optical reflection. This segmentation allows each layer to be optimized for its specific function while eliminating the need for the original growth substrate in the final device.
2Productivity
If a wavelength conversion structure is introduced in a flip chip structure, then light extraction efficiency is improved, but device structure becomes more complex
Solution Approach 1:
The patent inverts the conventional LED structure by placing the wavelength conversion layer at the lower cladding layer position rather than at the light-emitting surface. This inversion allows the wavelength conversion to occur before light enters the semiconductor stack, improving extraction efficiency while integrating the function into the existing support structure.
Solution Approach 2:
The lower cladding layer serves multiple functions: providing mechanical support to the semiconductor stack, acting as a distributed Bragg reflector for optical reflection, and containing the wavelength conversion layer for wavelength transformation. This multi-functionality reduces the need for separate components and simplifies the overall device structure.
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 effectively improves light extraction efficiency by converting light through the use of wavelength conversion materials and blocking unnecessary light, resulting in enhanced performance of the semiconductor light emitting device.
Implementation Method 1
a light-transmissive support having a first surface including a first region and a second region surrounding the first region, and a second surface opposing the first surface, and including a wavelength conversion material
Implementation Method 2
a light blocking film disposed on the second region of the light-transmissive support to surround or encompass the semiconductor stack
Implementation Method 3
a light-transmitting bonding layer disposed between the light-transmissive support and the semiconductor stack
Data Source
AI summary
A semiconductor light emitting device includes a light-transmissive support having a first surface including a first region and a second region surrounding the first region, and a second surface opposing the first surface, and including a wavelength conversion material, a semiconductor stack disposed above the first region of the first surface of the light-transmissive support, and including first and second conductivity-type semiconductor layers and an active layer disposed therebetween, a light-transmitting bonding layer disposed between the light-transmissive support and the semiconductor stack, a light blocking film disposed above the second region of the light-transmissive support to surround the semiconductor stack, and first and second electrodes respectively disposed on portions of the first and second conductivity-type semiconductor layers.