Color Conversion Element With Flattening Layers for Reduced Reflection Loss
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Solution Overview
Problem
There is a need to improve the conversion efficiency of color conversion elements, particularly in projection devices like projectors, where existing technologies do not effectively manage light reflection and heat dissipation.
Innovation Solution
A color conversion element is designed with a substrate, fluorescent part, first and second flattening layers, a reflective layer, and a joint part, where the flattening layers have lower surface roughness and higher transmittance to minimize light reflection and enhance light capture, and an air layer at the joint part to improve reflectance and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a reflective layer is superposed on the substrate to improve light reflection, then conversion efficiency is improved, but light scattering and reflection loss occur due to surface roughness
Solution Approach 1:
A flattening layer is introduced as an intermediary between the rough substrate surface and the reflective layer. This flattening layer has a first surface facing the fluorescent part and a second surface facing the reflective layer, where the second surface has lower surface roughness than the first surface. The flattening layer mediates between the rough substrate and the reflective layer, enabling the reflective layer to be formed on a smoother surface while still maintaining the substrate's heat dissipation properties.
Solution Approach 2:
The invention addresses the surface roughness problem by creating a multi-layer structure that transforms the rough surface into a smooth surface through an intermediate layer. The flattening layer effectively adds a new dimension to the interface between substrate and reflective layer, allowing the reflective layer to interact with a smoothed surface while the substrate maintains its original rough surface for heat dissipation.
2Temperature
If heat conductive adhesive is used to join fluorescent part and substrate, then heat dissipation is improved, but conversion efficiency decreases due to absorption of excitation light and emitted light
Solution Approach 1:
The adhesive layer is completely removed from the optical path between the substrate and the fluorescent part. Instead of using adhesive to join the fluorescent part to the substrate, the invention uses a flattening layer that can be joined without adhesive in the optical path, thereby eliminating the absorption of excitation light and emitted light that occurs with adhesive materials.
Solution Approach 2:
The flattening layer serves as a functional copy or replacement for the adhesive layer's joining function, but without the harmful optical absorption properties. The flattening layer provides both mechanical support and optical functionality, replacing the need for adhesive in the optical path while maintaining the heat dissipation capability through the substrate.
3Productivity
If the surface of the substrate is made rough to enhance light scattering, then light capture is improved, but reflection efficiency at the reflective layer decreases
Solution Approach 1:
The invention applies different surface quality characteristics to different regions and layers. The substrate's first surface (facing the fluorescent part) maintains higher roughness for light scattering and capture, while the flattening layer's second surface (facing the reflective layer) has lower roughness for optimal reflection. This local differentiation of surface quality allows both light capture and reflection efficiency to be optimized in their respective locations.
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 configuration enhances light capture and reflection efficiency while stabilizing the fluorescent part, reducing production costs, and improving heat dissipation, thereby increasing the overall conversion efficiency and longevity of the element.
Implementation Method 1
a reflective layer is superposed on a main surface of the substrate facing a fluorescent part, which consequently improves the conversion efficiency as a result of reflection of light from the fluorescent part at the reflective layer
Implementation Method 2
a fluorescent part and a substrate are joined with a heat conductive adhesive in order to improve heat dissipation in a phosphor foil (color conversion element)
Implementation Method 3
a fluorescent part and a substrate are joined with a heat conductive adhesive in order to improve heat dissipation
Data Source
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AI summary
A color conversion element (1) includes: a substrate (2); a fluorescent part (3) which is arranged above the substrate (2), receives laser light from an outside, and emits light of a color different from a color of the laser light; a first flattening layer (6) which is superposed on a first main surface of the fluorescent part (3) opposite to the substrate (2); a second flattening layer (7) which is superposed on a second main surface of the fluorescent part (3) facing the substrate (2); a reflective layer (4) which is superposed on a main surface of the second flattening layer (7) facing the substrate (2) and formed of a dielectric multilayer film; and a joint part (5) which lies between the reflective layer (4) and the substrate (2) and joins together the reflective layer (4) and the substrate (2).