Multi-LED Colorimeter Spectrum Matching for Fluorescence Control
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Solution Overview
Problem
Conventional colorimeters face challenges in accurately measuring chromaticity due to the influence of fluorescence generated from measured objects, particularly when using white LED light sources with spectra that differ significantly from standard light sources, leading to inaccurate reflectance and chromaticity calculations.
Innovation Solution
A colorimeter equipped with multiple light source units emitting different spectra, including a white LED and auxiliary LED sources with specific peak wavelengths, is designed to create a superimposed spectrum that approximates the reference spectrum of a D65 standard light source, thereby reducing the impact of fluorescence and enhancing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a white LED light source is used for color measurement, then the device complexity is reduced and energy consumption is lowered, but the measurement precision deteriorates due to spectral differences from standard light sources causing fluorescence interference
Solution Approach 1:
The white LED light source is segmented into multiple LED chips with different peak wavelengths (e.g., 450nm, 530nm, 630nm). Each LED chip emits light in a specific wavelength range, and by combining multiple segmented LED sources, the patent reconstructs a composite spectrum that approximates the standard D65 illuminant, thereby reducing fluorescence interference while maintaining LED advantages
Solution Approach 2:
The patent changes the spectral parameters of the light source by selecting LED chips with specific peak wavelengths and adjusting their intensity ratios. The controller independently controls the drive currents of each LED chip to dynamically adjust the emitted spectrum, transforming the fixed spectrum of a conventional white LED into a tunable spectrum that matches standard illumination conditions
2Device complexity
If the light source spectrum is simplified to use a single white LED, then the device structure is simplified, but the reliability of chromaticity calculation deteriorates due to significant spectral differences from the D65 standard light source
Solution Approach 1:
The single white LED is replaced with multiple LED chips emitting at different wavelengths. This segmentation allows the system to construct a composite spectrum that more closely matches the D65 standard, improving the reliability of chromaticity calculations while maintaining relatively simple LED-based structure
Solution Approach 2:
The patent uses a composite light source system combining multiple LED types (blue, green, red LED chips) to create a composite spectrum. This composite approach synthesizes a light source that mimics the D65 standard illuminant, enhancing measurement reliability while keeping the overall device structure compact and LED-based
3Measurement precision
If multiple LED light sources with different spectra are combined, then the measurement precision is improved by reducing fluorescence influence, but the device complexity increases
Solution Approach 1:
Multiple LED chips with different peak wavelengths are merged into a single integrated light source assembly. The controller统一管理 (unified management) of multiple LED drive circuits, and the optical system combines the emitted light through an integrating sphere or diffuser, merging multiple spectral components into one coherent illumination source that reduces fluorescence interference
Solution Approach 2:
The multi-LED light source system serves multiple functions: it can operate in different spectral configurations by adjusting which LED chips are active, adapt to different measurement requirements by changing intensity ratios, and maintain compatibility with existing color measurement algorithms. This multi-functionality justifies the increased complexity by providing enhanced measurement capabilities
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 colorimeter achieves more precise chromaticity measurements by suppressing the influence of fluorescence, allowing for accurate reflectance and chromaticity calculations in compliance with international standards, and enabling feedback control for optimizing production processes.
Implementation Method 1
a first light source unit configured to emit first irradiation light having a first spectrum; a second light source unit configured to emit second irradiation light having a second spectrum different from the first spectrum, a third light source unit configured to emit third irradiation light having a third spectrum different from the first spectrum and the second spectrum
Implementation Method 2
an integrating sphere configured to have irradiation light including the first irradiation light, the second irradiation light and the third irradiation light incident thereon
Implementation Method 3
When fluorescence is generated from the measured object in such a wavelength region, the influence of the fluorescence spectrum on the spectrum of the white light increases
Implementation Method 4
a light receiver configured to detect measured light resulting from irradiation of the measured object with the irradiation light emitted from the integrating sphere
Implementation Method 5
a controller configured to calculate an optical spectrum of the measured light based on a detection signal of the measured light
Data Source
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AI summary
A colorimeter 1 that measures a chromaticity of a measured object A comprises: a first light source unit 11 that emits first irradiation light having a first spectrum S1; a second light source unit 12 that emits second irradiation light having a second spectrum S2 different from the first spectrum S1; an integrating sphere 61 that has irradiation light including the first irradiation light and the second irradiation light incident thereon; a light receiver 20 that detects measured light resulting from irradiation of the measured object A with the irradiation light emitted from the integrating sphere 61; and a controller 50 that calculates an optical spectrum of the measured light based on a detection signal of the measured light. A superimposed spectrum S of the first spectrum S1 and the second spectrum S2 corresponds to a reference spectrum S0 of a standard light source as reference for calculating the chromaticity.