Semiconductor Light-Emitting Device Selective Transmission-Reflection Layer
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Solution Overview
Problem
Semiconductor light-emitting devices have limited luminous flux due to restricted light-emitting surfaces, necessitating an increase in light emission efficiency.
Innovation Solution
A semiconductor light-emitting device with a selective transmission-reflection layer comprising alternately stacked dielectric layers of varying optical thicknesses, optimized to enhance transmittivity for blue-green light and reflectivity for red light, thereby increasing the luminous flux through the light-emitting surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the light-emitting surface area is increased, then the luminous flux is improved, but the device structure becomes more complex
Solution Approach 1:
The patent changes the optical parameters of the device by introducing a selective transmission-reflection layer with specific optical thickness values. The layer has an optical thickness of 0.75 to 0.80, which is optimized to transmit blue-green light (450-550nm) while reflecting red light (600-750nm). This parameter optimization increases the luminous flux by enhancing the extraction efficiency of blue-green light without requiring an increase in the physical light-emitting surface area, thus resolving the contradiction between luminous flux and device structure complexity.
2Productivity
If a selective transmission-reflection layer is added, then the luminous flux is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the function of light management from the bulk semiconductor structure and concentrates it into a separate selective transmission-reflection layer. This layer is specifically designed to handle the transmission and reflection of light, allowing the rest of the semiconductor structure to focus on light generation. The extracted function is achieved through a relatively simple layered structure with optical thickness of 0.75 to 0.80, which can be integrated into existing devices without fundamentally redesigning the entire device architecture, thus limiting the increase in device complexity.
3Productivity
If the optical thickness is optimized for blue-green light transmission, then the luminous flux is improved, but the color rendering index may be affected
Solution Approach 1:
The patent applies local quality by making the selective transmission-reflection layer have different optical properties for different wavelength ranges. The layer is specifically designed with optical thickness of 0.75 to 0.80 to transmit blue-green light (450-550nm) while reflecting red light (600-750nm). This localized optimization of optical properties allows the layer to enhance blue-green light extraction for improved luminous flux while maintaining appropriate color rendering by preserving the red light component through reflection, thus resolving the contradiction between luminous flux and color rendering index.
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 the luminous flux by up to 2.3% while maintaining a comparable color rendering index, effectively addressing the limited light emission issue of semiconductor light-emitting devices.
Implementation Method 1
a selective transmission-reflection layer disposed on the light-emitting structure and including a plurality of dielectric layers having different optical thicknesses alternately stacked at least once
Implementation Method 2
the selective transmission-reflection layer may transmit blue-green light and reflect red light
Implementation Method 3
The optical thickness may be defined by a formula, (nd)/λ, where n is a refractive index of a respective dielectric layer
Data Source
AI summary
A semiconductor light-emitting device includes a light-emitting structure including a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer, and a selective transmission-reflection layer disposed on the light-emitting structure and including a plurality of dielectric layers having different optical thicknesses alternately stacked at least once. The sum of an optical thickness of a dielectric layer having a maximum optical thickness and an optical thickness of a dielectric layer having a minimum optical thickness is in the range of 0.75 to 0.80.