Self-calibrating spectrometers and auto-calibration methods
AssigneeSCI Instruments, Inc.
InventorJavier Ruiz
Life of this patent
Estimating the term…
Abstract
Auto-calibrating spectrometers and methods that measure transmission or reflection versus wavelength of a sample without need for calibration for long periods of time. Reflection and transmission spectrometers along with auto-calibrating methods for use therewith are disclosed. Light is focused onto a sample using a lens or similar optical element that transmits light towards the sample reflects light impinging upon it, and transmits light reflected from the sample. If one monitors the light reflected from the first lens and sample, very useful information is available related to the system response versus time. The present invention monitors the reflected light from the first lens and sample, and corrects for the system changes over time using this reflected light.
Claims18
An auto-calibrating spectrometer comprising:
- a light source;
- an optical element that transmits light and reflects a small amount of light;
- a detector for outputting electrical signals corresponding to light signals that are detected thereby;
- optical coupling apparatus that couples light from the light source to the optical element and a sample under measurement, and to the detector;
- a shutter assembly that selectively couples light or inhibits light from impinging upon and reflected by a reference sample having known reflection or the sample under measurement;
- and
- a controller coupled to the detector that processes the electrical signals output thereby and implements an algorithm that calculates a calibration value for the spectrometer at each wavelength of light output by the light source using a predetermined equation to autocalibrate the spectrometer.
An auto-calibrating method for use with a spectrometer comprising a light source, an optical element, a detector for outputting electrical signals corresponding to detected light signals, optical coupling apparatus that couples light from the light source to the optical element, and couples light reflected from the optical element and a sample under measurement to the detector, a shutter assembly that selectively couples light or inhibits light from impinging upon and reflected by a reference sample having known reflection or the sample under measurement, and a controller coupled to the detector that processes the electrical signals output thereby and implements the method to calculate a reflection value for the spectrometer at each wavelength of light output by the light source to autocalibrate the spectrometer, the method comprising the steps of:
- performing an initial calibration of the spectrometer;
- performing a background scan with the light source on and the second shutter assembly closed;
- performing a background scan, if required, with the light source off and the second shutter assembly open;
- performing a background scan with the light source off and the second shutter assembly closed;
- and
- performing a sample scan of the sample under measurement with the light source on and second shutter assembly open.
An auto-calibrating method for use with a spectrometer comprising a light source, an optical element, first and second detectors for outputting electrical signals corresponding to detected light signals, a shutter assembly that selectively couples light or inhibits light from impinging upon and reflected by a reference sample having known reflection or the sample under measurement, optical coupling apparatus for coupling light from the light source to the optical element, and coupling light reflected from the optical element and a sample under measurement to the first detector, and for coupling light that is transmitted by or reflected off of the sample under measurement to the second detector, and a controller coupled to the first and second detectors that processes the electrical signals output thereby and implements the method to calculate a transmission value for the spectrometer at each wavelength of light output by the light source to autocalibrate the spectrometer, the method comprising the steps of:
- performing an initial calibration of the spectrometer;
- performing a background scan of the first and second detectors with the light source on and the second shutter assembly closed;
- performing a background scan, if required, of the first and second detectors with the light source off and the second shutter assembly open;
- performing a background scan, if required, of the first and second detectors with the light source off and the second shutter assembly closed;
- and
- performing a sample scan using the first detector of an unknown sample with the light source on and second shutter assembly open.
Dependencies are inferred from the claim text.