Solid State Illumination System for Fluorescence Imaging
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Solution Overview
Problem
Conventional high brightness illumination systems for fluorescence imaging and analysis, particularly in the 540 nm to 630 nm spectral band, face limitations due to the lack of suitable semiconductor materials for LEDs, resulting in insufficient radiance compared to traditional arc lamps, especially in the green/yellow/amber range.
Innovation Solution
A method involving a light emitting diode (LED) and a phosphor layer, where the LED emits a first wavelength within the absorption band of the phosphor, and a laser optically pumps the phosphor to increase emission intensity in the green, yellow, and amber regions, providing high radiance illumination at specific wavelengths like 545 nm and 575 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional arc lamps are used for illumination, then high radiance is achieved, but short lifetime and high voltage operation occur
Solution Approach 1:
The patent replaces conventional arc lamp illumination systems with solid-state LED-based illumination systems. This substitution eliminates the mechanical and thermal stress issues inherent in arc lamps, providing extended lifetime while maintaining high radiance through advanced LED technology and phosphor conversion mechanisms.
Solution Approach 2:
The patent employs parameter changes by utilizing LEDs with specific wavelength emissions (e.g., 450nm blue LEDs) combined with phosphor materials that convert the light to desired wavelengths. This allows optimization of both radiance output and operational lifetime by selecting appropriate LED and phosphor combinations.
2Illumination intensity
If conventional arc lamps are used for illumination, then high radiance is achieved, but high voltage operation is required
Solution Approach 1:
The patent replaces high-voltage arc lamp operation with low-voltage LED operation. LEDs require only a few volts to operate, eliminating the need for high-voltage power supplies and associated safety concerns, while still achieving high radiance through efficient electroluminescence and phosphor conversion.
3Illumination intensity
If conventional arc lamps are used for illumination, then high radiance is achieved, but mercury is used which is an environmental hazard
Solution Approach 1:
The patent replaces mercury-containing arc lamps with mercury-free LED-based illumination systems. This substitution eliminates environmental hazards associated with mercury disposal while maintaining high radiance output through solid-state light emission and phosphor wavelength conversion.
4Duration of action of moving object
If solid state LED light sources are used, then improved lifetime and lower voltage operation are achieved, but insufficient radiance is provided in the 540 nm to 630 nm spectral band
Solution Approach 1:
The patent introduces phosphor materials as intermediaries that convert blue LED light (450nm) to green, yellow, and red wavelengths. This phosphor conversion mechanism enables solid-state LEDs to achieve sufficient radiance in the 540nm to 630nm spectral band while maintaining the advantages of long lifetime and low voltage operation.
Solution Approach 2:
The patent employs composite material systems combining blue LEDs with multiple phosphor materials (e.g., YAG:Ce for yellow, red phosphors for 630nm emission). This composite approach enables broad spectral coverage with high radiance in previously problematic wavelength regions while retaining solid-state reliability.
5Ease of operation
If solid state LED light sources are used, then electronic control capability is achieved, but insufficient radiance is provided in the green/yellow/amber range
Solution Approach 1:
The patent uses phosphor materials as intermediaries to convert LED output to the required green, yellow, and amber wavelengths. This enables electronic control of illumination in these spectral regions while achieving sufficient radiance through optimized phosphor selection and LED-phosphor coupling.
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 approach significantly enhances the optical output in the 545 nm and 575 nm regions, matching or exceeding the radiance of traditional arc lamps, while offering the advantages of solid-state lighting such as lower voltage operation and reduced mercury usage.
Implementation Method 1
a first light source comprising a light emitting device (LED) and a phosphor layer, the LED emitting a first wavelength λ1 within an absorption band of the phosphor layer and the phosphor layer emitting broadband light emission of longer wavelength
Implementation Method 2
concurrently optically pumping the phosphor layer with laser emission λ2 to increase emission intensity in the phosphor emission wavelength band ΔλPHOSPHOR
Data Source
AI summary
An illumination system includes a phosphor to emit light in a wavelength band ΔλPHOSPHOR, a second light source to emit light at a second wavelength λ2 within an absorption band of the phosphor, a third light source to emit light at a third wavelength λ3 and a fourth light source to emit light at a fourth wavelength λ4. A controller drives the second, third and fourth light sources. A first dichroic optical element: 1) directs light from the phosphor to an optical output of the system, 2) directs light from the third light source to the optical output, and 3) directs light from the fourth light source to the optical output. A second dichroic optical element: 1) directs light from the third light source to the first dichroic optical element, and 2) directs the light from the fourth light source to the first dichroic optical element.