Dome-Shaped Fluorescent Material for Uniform LED Illumination
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Solution Overview
Problem
Conventional light source devices with fluorescent materials exhibit uneven light distribution due to higher excitation light intensity near the optical axis and lower intensity at the circumferential edge, resulting in non-uniform illumination.
Innovation Solution
A light source device incorporating a first excitation light source, a first optical member that absorbs and converts excitation light, and a second optical member with a larger divergence angle, ensuring equal or greater light intensity at the optical axis, and a holding member to adjust the divergence angle of the excitation light for uniform illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a plate-shaped fluorescent material is disposed on the LED chip to convert wavelength, then the illumination light is adjusted by excitation light and fluorescence, but the light distribution becomes uneven with stronger excitation light component in the center and weaker fluorescent component at the circumferential edge
Solution Approach 1:
The patent changes the geometric parameters of the fluorescent material from a plate shape to a dome shape with specific curvature radius (R1) and base diameter (D1). This parameter change modifies the light path and scattering characteristics, enabling more uniform light distribution across the illumination area while maintaining effective wavelength conversion.
Solution Approach 2:
The patent applies different properties to different regions of the fluorescent material by designing a dome shape where the curvature radius varies from the center to the edge. The dome structure creates different light interaction paths for central and peripheral regions, with the center providing stronger fluorescence conversion and the edges allowing more excitation light transmission, thereby achieving uniform overall distribution.
2Use of energy by moving object
If the excitation light intensity is higher near the optical axis, then the fluorescence conversion is more efficient at the center, but the light intensity becomes lower at the circumferential edge resulting in non-uniform illumination
Solution Approach 1:
The dome-shaped fluorescent material with specific curvature radius (R1) and base diameter (D1) parameters creates optimized light paths. The curved surface geometry ensures that excitation light from the LED chip is distributed more evenly across the fluorescent material surface, allowing both central and peripheral regions to contribute effectively to fluorescence conversion while maintaining uniform illumination output.
Solution Approach 2:
The patent transitions from a two-dimensional plate-shaped fluorescent material to a three-dimensional dome structure. This dimensional change adds vertical curvature that redirects light paths, allowing excitation light to interact with the fluorescent material more uniformly across different radial positions, thereby balancing conversion efficiency with uniform light distribution.
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 achieves uniform light distribution by increasing the divergence angle of the excitation light, reducing light intensity variations across the illumination area, and enhancing energy conversion efficiency.
Implementation Method 1
a first optical member configured to absorb at least part of the first excitation light, convert a wavelength of the part of the first excitation light to emit first wavelength converted light
Implementation Method 2
the second optical member increasing the divergence angle of the transmitted first excitation light by a second incremental angle larger than the first incremental angle
Data Source
AI summary
A light source device includes a first excitation light source which emits first excitation light having a wavelength in a first wavelength region, a first optical member, a second optical member and a holding member which holds the first optical member and the second optical member. The first optical member converts at least part of the first excitation light to emit first wavelength converted light, and increase divergence angle of the transmitted first excitation light by a first incremental angle. A second optical member is disposed in a region including an optical axis of the first excitation light, and increases the divergence angle of the transmitted first excitation light by a second incremental angle larger than the first incremental angle.