Wavelength-Conversion LED Coating for Color Control and Light Extraction
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Solution Overview
Problem
Current semiconductor light-emitting devices face challenges in precisely controlling emission colors and improving luminous efficiency, as they struggle to effectively convert and transmit light wavelengths efficiently.
Innovation Solution
A light-emitting device is designed with a semiconductor light-emitting structure, a wavelength conversion layer, and a multi-inorganic-film coating layer, where the multi-inorganic-film coating layer includes a distributed Bragg reflector structure with alternately stacked inorganic films, allowing for controlled transmission of light wavelengths and enhancing luminous flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a wavelength conversion layer is used to convert light wavelengths, then emission color control is improved, but luminous efficiency deteriorates due to insufficient light transmission
Solution Approach 1:
A multi-inorganic-film coating layer is introduced as an intermediary component between the wavelength conversion layer and the external environment. This coating layer acts as a mediator that selectively manages light transmission, allowing both converted and unconverted light to pass through while maintaining emission color precision and improving luminous efficiency.
Solution Approach 2:
The multi-inorganic-film coating layer is constructed from multiple inorganic materials with different optical properties. By combining materials with varying refractive indices and transmission characteristics, the coating achieves optimized light management that simultaneously preserves emission color accuracy and enhances luminous flux transmission.
2Manufacturing precision
If phosphor materials are used for wavelength conversion, then emission color is controlled, but luminous flux is reduced due to excessive phosphor absorption
Solution Approach 1:
The multi-inorganic-film coating layer applies different local properties to different regions of the light path. Specific inorganic films are positioned and configured to have different thicknesses and compositions, creating localized optical characteristics that optimize both color control and light transmission in different areas of the device.
Solution Approach 2:
The coating layer modifies optical parameters such as refractive index, film thickness, and material composition to optimize light transmission. By carefully controlling these parameters, the system achieves improved luminous flux while maintaining precise emission color control through the wavelength conversion layer.
3Device complexity
If a simple coating layer is used, then device complexity is reduced, but light extraction efficiency deteriorates
Solution Approach 1:
The coating structure is segmented into multiple inorganic film layers, each with specific functions. This segmentation allows the system to achieve high light extraction efficiency through optimized optical interference and transmission in each layer, while the modular structure maintains manageable device complexity.
Solution Approach 2:
The solution moves from a single-layer coating approach to a multi-dimensional inorganic film stack. By adding the dimension of multiple layers with varying optical properties, the system achieves superior light extraction efficiency without proportionally increasing device complexity, as each layer serves a specific optical function.
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 configuration enables precise control of emission colors and improves luminous efficiency by simultaneously transmitting and converting light wavelengths, reducing the need for excessive phosphor materials and enhancing the light extraction efficiency.
Implementation Method 1
a wavelength conversion layer facing the light-emitting surface and configured to convert at least a portion of the light which has the first wavelength into light having a second wavelength that is greater than the first wavelength
Implementation Method 2
The multi-inorganic-film coating layer includes a distributed Bragg reflector (DBR) structure including a plurality of inorganic films, in which a first inorganic film having a first refractive index and a second inorganic film having a second refractive index are alternately stacked
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A light-emitting device includes: a semiconductor light-emitting structure configured to emit light having a first wavelength; a wavelength conversion layer configured to convert the light which has the first wavelength into light having a second wavelength that is greater than the first wavelength; and a multi-inorganic-film coating layer spaced apart from a light-emitting surface with the wavelength conversion layer therebetween. The multi-inorganic-film coating layer includes a distributed Bragg reflector structure in which first and second inorganic films are alternately stacked, and an uppermost inorganic film farthest from the wavelength conversion layer from among the plurality of inorganic films has a greatest thickness in a first direction perpendicular to the light-emitting surface of the semiconductor light-emitting structure. The first refractive index is selected from a range of about 1.1 to about 1.5, and the second refractive index is selected from a range of about 2.0 to about 3.0.