Wavelength Conversion Element Air Gap Design
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Solution Overview
Problem
Wavelength conversion elements experience fluorescence loss due to reflection off the reflection surface, leading to a decrease in light emission efficiency.
Innovation Solution
A wavelength conversion element is designed with a bonding section that separates the reflection surface and the wavelength conversion section, creating an air layer and using a dielectric multilayer film to enhance light reflection and reduce thermal resistance, while maintaining the distance between these surfaces using maintaining members and allowing communication with external space through openings in the bonding section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a reflection surface is provided to reflect fluorescence, then fluorescence extraction is improved, but fluorescence loss occurs due to reflection resulting in decreased light emission efficiency
Solution Approach 1:
The wavelength conversion element is divided into multiple functional sections: an excitation light incident section where excitation light enters the wavelength conversion layer, and a fluorescence extraction section where converted fluorescence is extracted. This segmentation allows optimized light paths for both excitation and fluorescence, reducing unnecessary reflections and improving overall efficiency.
Solution Approach 2:
Instead of using a traditional reflection surface to redirect fluorescence, the patent inverts the approach by designing the element to directly extract fluorescence in the conversion direction. The excitation light incident section and fluorescence extraction section are positioned to minimize reflective losses while maximizing direct fluorescence extraction.
2Device complexity
If the wavelength conversion layer is bonded directly to the base, then structural simplicity is maintained, but thermal management becomes difficult leading to decreased light emission efficiency
Solution Approach 1:
A heat dissipation layer is introduced as an intermediary between the wavelength conversion layer and the base. This heat dissipation layer serves as a thermal conduit that efficiently transfers heat away from the wavelength conversion layer, preventing thermal accumulation that would otherwise decrease light emission efficiency.
Solution Approach 2:
The element employs composite material construction with distinct layers having different thermal and optical properties. The heat dissipation layer is specifically selected for its thermal conductivity properties, creating a composite structure that optimizes both thermal management and optical performance.
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 increases light emission efficiency by reducing fluorescence loss at the reflection surface and maintaining high efficiency despite thermal challenges, allowing for improved projector performance with high-luminance image display.
Implementation Method 1
a wavelength conversion layer provided on a surface of the reflector that is the surface opposite the substrate and converts excitation light in terms of wavelength into fluorescence
Implementation Method 2
a reflection surface provided between the reflector and a surface of the wavelength conversion layer that is the surface opposite the reflector and totally reflecting fluorescence incident on the reflection surface at angles of incidence greater than or equal to the critical angle
Data Source
AI summary
A wavelength conversion element according to an aspect of the invention includes a base having a reflection surface, a wavelength conversion section that has a first surface on which excitation light is incident and a second surface facing away from the first surface and converts the excitation light in terms of wavelength into fluorescence, and a bonding section that bonds the wavelength conversion section to the base. Bonding the wavelength conversion section to the base via the bonding section with the reflection surface and the second surface separate from each other provides an air layer in part of the space between the reflection surface and the second surface, and at least part of a portion of the first surface that is the portion facing the air layer is a light incident area on which the excitation light is incident.