Wavelength Conversion Element With Graded Phosphor Absorption
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Solution Overview
Problem
Existing projector technologies face challenges in efficiently dissipating heat from phosphor layers, leading to reduced light emission efficiency and potential deterioration due to high thermal resistance and temperature quenching.
Innovation Solution
A wavelength conversion element with a phosphor layer having regions of varying absorption coefficients, where the absorption amount increases closer to the base material, allowing for efficient heat transfer and dissipation, thereby suppressing temperature quenching and enhancing light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the phosphor layer uses a uniform absorption coefficient, then the structure is simple, but the heat dissipation is poor and thermal resistance is high
Solution Approach 1:
The phosphor layer is designed with non-uniform absorption coefficient distribution, where the absorption coefficient varies continuously from the incident surface to the heat dissipating substrate. This local variation optimizes heat dissipation by allowing regions closer to the substrate to absorb more excitation light and generate heat that can be efficiently conducted to the substrate, while regions farther away maintain lower absorption to reduce heat accumulation.
2Productivity
If the phosphor layer absorbs more excitation light, then the light emission efficiency increases, but the heat generation increases and causes temperature quenching
Solution Approach 1:
The absorption coefficient is used as a variable parameter that changes continuously through the phosphor layer thickness. By adjusting this parameter spatially, the patent achieves optimal balance between light emission efficiency and heat management, allowing the phosphor layer to absorb sufficient excitation light for high luminance while distributing heat generation to regions that can effectively dissipate it.
3Illumination intensity
If the excitation light intensity is increased, then the luminance output increases, but the heat generation increases and may deteriorate the joint portion
Solution Approach 1:
The non-uniform absorption coefficient distribution creates localized heat management zones within the phosphor layer. Regions with higher absorption coefficients are positioned where heat can be effectively conducted to the substrate, while regions with lower absorption coefficients reduce heat accumulation. This spatial differentiation allows the system to handle higher excitation light intensities for improved luminance without compromising joint portion reliability.
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 dissipates heat, maintaining light emission efficiency and extending the lifespan of the light source device, enabling the projection of bright images over a longer period.
Implementation Method 1
a phosphor layer including a phosphor that is excited by excitation light from the solid light source and emits fluorescence having a wavelength longer than the emitted wavelength of the solid light source
Implementation Method 2
since most of the excitation light is absorbed on the incident side of the phosphor layer
Data Source
AI summary
A wavelength conversion element includes a base material and a phosphor layer that contains a phosphor emitting fluorescence upon incidence of excitation light and is provided on the base material, in which the phosphor layer includes a first surface on which excitation light (blue light) is incident and a second surface facing the base material, and a plurality of regions with different absorption coefficients of the excitation light between the first surface and the second surface.