Light Source Device Wavelength Conversion Layer Focal Point
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Solution Overview
Problem
In light source devices with a laser diode as an excitation light source, the wavelength conversion efficiency decreases due to the light saturation phenomenon, where high optical density of excitation light at the wavelength conversion layer leads to reduced conversion efficiency, even with heat dissipation mechanisms.
Innovation Solution
A light source device configuration with a collecting system focal point inside the wavelength conversion layer, utilizing both the first and second light incident surfaces to distribute excitation light entry, and a support member for heat dissipation, including a light-transmissive member formed from sapphire for improved heat conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the optical density of excitation light in the light incident surface of the wavelength conversion layer is increased, then the light extraction efficiency is improved, but the wavelength conversion efficiency decreases due to light saturation phenomenon
Solution Approach 1:
The invention transitions from single-surface light entry to multi-surface light entry by forming the focal point inside the wavelength conversion layer. This causes excitation light to enter from both the first light incident surface and the second light incident surface (side surfaces), effectively adding dimensional pathways for light entry and distributing the optical density across multiple surfaces.
Solution Approach 2:
The invention creates non-uniform light distribution by forming the focal point at a specific location inside the wavelength conversion layer rather than on the surface. This localizes the high intensity region within the bulk material, allowing the surface areas to have lower optical density while still achieving efficient light extraction through the combined effect of multiple entry surfaces.
2Temperature
If a heat dissipation member is provided around the wavelength conversion layer, then temperature rise is suppressed, but wavelength conversion efficiency still decreases unless optical density is reduced
Solution Approach 1:
The invention addresses the heat dissipation issue by changing the light entry geometry from single-surface to multi-surface through internal focal point formation. This dimensional change in light pathways reduces the optical density at any single surface, thereby preventing light saturation and improving wavelength conversion efficiency while maintaining effective heat dissipation through the wavelength conversion layer.
3Ease of operation
If the focal point is formed on the light exiting surface, then excitation light enters from distributed positions, but optical density on incident surfaces remains high
Solution Approach 1:
The invention nests the focal point formation inside the wavelength conversion layer rather than on the surface. This nested configuration allows the focal point to be positioned within the material volume, enabling light to enter from multiple surfaces (first and second light incident surfaces) while the focal convergence occurs internally, distributing the effective light entry across the structure.
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 reduces optical density at the wavelength conversion layer, suppresses the light saturation phenomenon, and enhances wavelength conversion efficiency while maintaining reliable heat dissipation, leading to improved performance in light source devices and projectors.
Implementation Method 1
a wavelength conversion layer having a first light incident surface crossing a traveling direction of the excitation light, a light exiting surface opposed to the first light incident surface, and a second light incident surface coupling an end portion of the first light incident surface and an end portion of the light exiting surface, wherein a focal point of the collecting system is formed inside of the wavelength conversion layer, and the wavelength conversion layer wavelength-converts the excitation light entering from the first light incident surface and the second light incident surface and generates a fluorescent light
Implementation Method 2
a light-transmissive member that transmits the excitation light output from the collecting system
Implementation Method 3
a collecting system that collects the excitation light, wherein a focal point of the collecting system is formed inside of the wavelength conversion layer
Data Source
AI summary
The light source device of the invention includes an excitation light source that outputs an excitation light, a collecting system that collects the excitation light source, a first light-transmissive member that transmits the excitation light output from the collecting system, and a wavelength conversion layer having a first light incident surface crossing a traveling direction of the excitation light, a light exiting surface opposed to the first light incident surface, and a second light incident surface coupling an end portion of the first light incident surface and an end portion of the light exiting surface, wherein a focal point of the collecting system is formed inside of the wavelength conversion layer, and the wavelength conversion layer wavelength-converts the excitation light entering from the first light incident surface and the second light incident surface and generates a fluorescent light.