Spectrometer Calibration via Defocused Radiation
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Solution Overview
Problem
Spectrometers using line sensors for ultraviolet to near-infrared light element analysis face burn-in effects, leading to reduced sensitivity over time, which complicates accurate element content determination due to non-homogeneous illumination and damage to fluorescent layers or pixels, making existing calibration methods ineffective for UV ranges.
Innovation Solution
A method involving the generation of radiation with multiple spectral lines, defocusing to distribute light across pixels, calculating correction factors based on adjacent pixel measurements, and applying these factors to adjust measured values, ensuring each pixel is exposed to similar wavelengths for precise correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light source irradiating all pixels with the same brightness is used for calibration, then pixel-specific sensitivity functions can be determined, but homogeneous illumination across all pixels cannot be achieved
Solution Approach 1:
The patent applies local quality by using defocused radiation to create a spatial distribution of illumination where each pixel receives radiation from a specific angular range. This allows each pixel to be calibrated with radiation appropriate to its detection characteristics while accounting for position-dependent variations in illumination across the sensor array.
Solution Approach 2:
The patent changes the optical parameter of radiation focus from focused to defocused state. By defocusing the radiation, the light is distributed across multiple pixels with controlled intensity distribution, enabling accurate sensitivity determination for each pixel while accounting for the actual illumination conditions that will prevail during measurement operations.
2Measurement precision
If visible light is used for calibration of UV-range sensors, then pixel sensitivity can be calibrated, but damage to fluorescent layers cannot be detected
Solution Approach 1:
The patent converts the harmful effect of UV radiation (which can damage fluorescent layers) into a beneficial calibration method. By using defocused UV radiation for calibration, the method detects sensitivity changes in pixels that result from fluorescent layer degradation, thereby identifying and compensating for damage that would otherwise go undetected during visible light calibration.
Solution Approach 2:
The patent uses defocused radiation as an intermediary that distributes UV light across multiple pixels in a controlled manner. This intermediary approach allows calibration with UV radiation while reducing the concentrated energy exposure that would cause damage, and simultaneously enables detection of fluorescent layer degradation through sensitivity changes.
3Ease of manufacture
If a UV radiation source at a fixed wavelength is used for calibration, then calibration can be performed, but accurate correction for each pixel cannot be achieved
Solution Approach 1:
The patent segments the calibration process by determining sensitivity functions for each pixel individually rather than using a single correction factor for all pixels. By analyzing the response of each pixel to defocused UV radiation separately, the method accounts for position-dependent variations and damage patterns, enabling accurate pixel-specific corrections while maintaining a relatively simple overall calibration procedure.
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 effectively identifies and compensates for reduced pixel sensitivity, providing accurate element content determination by ensuring uniform illumination and correcting burn-in effects across all pixels, even in UV ranges where fluorescent layers are damaged.
Implementation Method 1
a dispersive element (3), on which a radiation (1) with a plurality of spectral lines in the range of ultraviolet and visible light falls from an entry slot (2)
Implementation Method 2
the sensor must be provided with a fluorescent layer which protects the sensor from destruction by UV radiation and by converting the UV radiation into visible light
Data Source
AI summary
The invention relates to a method and a spectrometer for wavelength-dependent measurement of radiation in the range of UV light and visible light, with an entry gap, a dispersive element and a number of sensors comprising pixels, wherein a light path runs inside the spectrometer from the entry slot to the sensors and an imaging element is provided, which focusses the radiation on the sensors, in the case of which a means for defocussing the radiation is provided, which is activatable for the purpose of calibration.