Rear-Pumped Fluorescent Light Source With Parabolic Mirror
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Solution Overview
Problem
Current solid-state broadband fluorescent light sources, such as those using LEDs, suffer from low spectral radiance due to low radiance pump sources, leading to poorly collimated or focused light beams, which are unsuitable for long-range or high-resolution applications, and complicate thermal management and manufacturing processes.
Innovation Solution
A light source design incorporating a parabolic mirror to focus stimulus light onto a fluorescent body, with pump light sources positioned behind the output beam, allowing for increased spectral radiance, improved thermal management, and simplified manufacturing by reducing the number of optical elements and aligning components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If front-surface pumping schemes are employed to achieve higher radiance, then spectral radiance is improved, but device complexity and manufacturing difficulty increase due to multiple optical elements and alignment requirements
Solution Approach 1:
The patent inverts the conventional front-surface pumping arrangement by positioning pump light sources at the rear of the fluorescent body instead of in front. This rear-pumping configuration eliminates the need for complex front-side optical steering and focusing elements, significantly reducing device complexity while maintaining high spectral radiance through direct rear illumination of the fluorescent material.
Solution Approach 2:
The patent transitions from planar front-surface pumping to three-dimensional rear-pumping geometry. By positioning pump sources at the rear and using a rear reflector to redirect light forward through the fluorescent body, the system achieves high radiance output without requiring multiple front-side optical elements, thus simplifying the overall optical architecture.
2Illumination intensity
If front-surface pumping schemes are employed to achieve higher radiance, then spectral radiance is improved, but ease of manufacture deteriorates due to assembly difficulties in high-volume production
Solution Approach 1:
By inverting the pumping geometry to rear-pumping configuration, the patent eliminates complex front-side optical alignments that are difficult to automate. The rear-pumping design allows for simpler assembly procedures where pump sources are positioned at the rear and automatically aligned with the fluorescent body, making the system suitable for high-volume manufacturing.
3Illumination intensity
If multiple pump sources are positioned in front of the fluorescent body to achieve higher radiance, then spectral radiance is improved, but thermal management complexity increases due to multiple heat sinks
Solution Approach 1:
The patent merges multiple heat management functions into a single integrated rear heat sink structure. By positioning all pump light sources at the rear and using a common rear reflector and heat sink assembly, the system consolidates thermal management into one location, eliminating the need for multiple distributed heat sinks and simplifying the thermal management architecture.
4Adaptability or versatility
If broadband incoherent light sources are used to provide stimulation, then suitability for biomedical applications is improved, but device size increases requiring large optical systems and reflectors
Solution Approach 1:
The patent inverts the conventional optical architecture by using rear-pumping configuration with a rear reflector. This inversion allows the system to achieve high spectral radiance output in a compact form factor, eliminating the need for large front-side optical systems and reflectors while maintaining broadband emission suitable for biomedical applications.
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 design achieves high spectral radiance with a compact and cost-effective light source, suitable for high-volume manufacturing, and enhances thermal management by integrating pump light sources with a single thermal sink, while maintaining efficient light collection and alignment.
Implementation Method 1
a parabolic mirror, positioned to have a focal axis directed at the body and having reflective surfaces disposed outside of a collection area of the output beam so that the collection area is not obstructed by the parabolic mirror
Implementation Method 2
a body having a material doped to have a fluorescent property when stimulated at a stimulus wavelength
Implementation Method 3
the parabolic mirror focuses the stimulus light provided by the one or more light sources at the body to stimulate emission of the light emitted by the body
Implementation Method 4
a collecting lens for collecting the light emitted by the body
Data Source
AI summary
A pumped fluorescent light source includes a parabolic mirror that is positioned to focus pumping light from one or more pump sources on a fluorescent body. The resulting assembly provides for heat collection from a back surface of the light source for both the fluorescent body and the pumping sources in a compact package that may be hermetically sealed. The parabolic mirror has reflective surfaces disposed outside of a collection area of an output beam of the light sources, so that the collection area is not obstructed by the parabolic mirror. The light source also includes a collecting lens for collecting the light emitted by the body. The parabolic mirror focuses the stimulus light on the fluorescent body to stimulate emission. An additional parabolic mirror may be included behind the fluorescent body to focus the fluorescent emissions that do not directly enter the collection area at a point of collection.