Integrating Sphere Photometer Spectral Response Calibration
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Solution Overview
Problem
Existing integrating sphere photometers face challenges in accurately measuring spectral responsivity due to spectral mismatch errors, especially for narrow-band light sources, and existing methods for correcting these errors are costly and complex, making them unsuitable for industrial applications.
Innovation Solution
A method and system for measuring the spectral responsivity of integrating sphere photometers using a broadband photodetector mounted on the sphere wall, which involves measuring the response to multiple reference light sources with different peak wavelengths, calculating spectral responsivity through numerical solution, and using LED, laser, or adjustable light sources with overlapping spectra to achieve accurate results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spectral comparison devices based on tunable lasers or lamp-monochromator systems are used to measure spectral responsivity, then measurement precision is improved, but device complexity and economic cost increase significantly
Solution Approach 1:
The patent introduces a spectrometer as an intermediary device to measure the spectral power distribution of light sources, replacing the need for complex tunable laser or lamp-monochromator systems. The spectrometer captures spectral information across multiple wavelengths simultaneously, serving as a mediator between the light source and the integrating sphere photometer, thereby simplifying the overall measurement system while maintaining accuracy.
Solution Approach 2:
The patent replaces mechanical scanning systems (tunable lasers, lamp-monochromators that require moving parts for wavelength selection) with a non-mechanical spectrometer-based approach. The spectrometer uses fixed diffraction gratings or prisms combined with detector arrays to achieve wavelength separation without mechanical movement, eliminating complex mechanical systems while preserving spectral measurement capabilities.
2Measurement precision
If spectral comparison devices with traceable spectral responsivity are used, then measurement accuracy is improved, but economic cost increases making them unsuitable for industrial applications
Solution Approach 1:
The patent employs commercially available, cost-effective components such as standard integrating spheres, broadband photodetectors, and spectrometers that can be purchased off-the-shelf. These components do not require expensive traceable calibration standards or custom manufacturing, making the system economically viable for industrial applications while maintaining sufficient measurement accuracy through the proposed measurement methodology.
Solution Approach 2:
The patent creates a measurement system using universal, multi-functional components that can be applied to various light source types (LEDs, lasers, lamps) without requiring specialized expensive equipment for each application. The integrating sphere photometer combined with spectrometer serves multiple measurement functions, reducing the need for application-specific custom equipment and lowering overall system cost.
3Measurement precision
If the integrating sphere photometer system is regarded as a whole for spectral responsivity measurement, then comprehensive spectral mismatch error evaluation is achieved, but sensitivity compared to reference detectors decreases
Solution Approach 1:
The patent segments the spectral responsivity measurement process into two independent parts: (1) measuring the spectral power distribution of light sources using a spectrometer, and (2) measuring the photometer response to these known spectral distributions. This segmentation allows the system to evaluate spectral mismatch errors comprehensively while maintaining sensitivity, as each component can be optimized independently rather than requiring the entire system to match reference detector sensitivity.
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 method provides a cost-effective and accurate means to measure and correct spectral responsivity, suitable for industrial applications, by using a combination of LED, laser, or adjustable light sources with overlapping spectra to enhance measurement accuracy and reduce equipment complexity.
Implementation Method 1
an integrating sphere consisting of an integrating sphere and a broadband photodetector, wherein the broadband photodetector is mounted on the sphere wall of the integrating sphere
Implementation Method 2
the broadband photodetector is mounted on the sphere wall of the integrating sphere
Data Source
AI summary
An integrating sphere photometer spectral response measurement system has an integrating sphere photometer and three or more reference light sources having different peak wavelengths. The integrating sphere photometer has an integrating sphere and a broadband photodetector, wherein the broadband photodetector is mounted on a sphere wall of the integrating sphere. Emergent light of the reference light sources is incident to the integrating sphere. The total spectral radiation flux Pi(λ)(i=1, 2, . . . n) received by an integrating sphere photometer system is acquired; the response Mi(i=1, 2, . . . n) of a photometer of mixed light in the integrating sphere is read by the broadband photodetector; an equation set is established; and the spectral responsivity Srel(λ) of the integrating sphere photometer is obtained by means of numerical solution.