Shimadzu Corporation

Shimidzu Corporation of 1

Toshiaki Fukuma

Osamu Ando

Tatsumi Sato

Hidehisa Nishigaki

A spectrophotometer of the type using a pulse motor to rotate a diffraction grating through a speed reducing mechanism has a capability of constructing a conversion table according to a program, by which table a rotation amount of the motor is converted to a corresponding wavelength of output light from a monochromator. The spectrophotometer is capable of designating a calibration mode in which an emission peak at a known wavelength of light from a light source is detected, a coefficient in a conversion equation is determined on the basis of the known wavelength of the emission peak and a rotation amount of the motor at a time when the emission peak is detected, and the determined coefficient is used to construct the conversion table which is then stored in a nonvolatile memory. In an analysis mode, a rotation amount of the motor is converted to a corresponding wavelength in accordance with the conversion table in the nonvolatile memory.

Method and apparatus for calibrating a spectrophotometer

A spectrophotometer including: a) a light source switching mechanism for switching a plurality of light sources by swinging a light source mirror; b) a filter selecting mechanism; c) a diffraction grating rotating mechanism; and d) a controller for determining the operation origins of the three driving mechanisms using a rough origin sensor provided for the diffraction grating rotating mechanism and a photometer. The operation of the controller is to: i) determine an origin of the movement of the filter by making an end of the filter frame to touch a stopper; ii) determine a rough origin of the diffraction grating using the rough origin sensor; and iii) determine an origin of the movement of the light source mirror and a precise origin of the movement of the diffraction grating by detecting the position at which the photometer detects the maximum intensity of light.

Spectrophotometer

A spectrophotometer provided with: a sample changer for holding a plurality of samples to be analyzed, each of which is given an identification code, and positioning a selected one of the samples for measurement; means for setting a measuring wavelength for each of the identification codes of the samples; means for setting an identification code for the measured data of each of the samples; means for setting a coefficient to be used for processing the measured data of each of the samples together with an identification code; means for setting an operation expression composed of the identification codes of the measured data of the samples and the identification code of the coefficient; means for storing the data obtained by measuring each of the samples with the corresponding one of the wavelengths set for the sample held by the sample changer in correspondence with the corresponding one of the identification codes of the measured data; and means for reading out the data stored in the storing means and the coefficient set in the setting means in accordance with the identification codes of the measured data and the coefficient which constitute the operation expression set in the setting means, and performing an operation for data processing in accordance with the operation expression.

A spectrophotometer comprising a light source, a spectroscope which separates the light of light source depending on the wavelengths, chops the light into the first and second light beams and allows the light beams to pass through the reference cell and sample cell, a photodiode which alternately receives the light beams from the reference cell and sample cell, a variable gain amplifier which amplifies a light current of photodiode, an A/D converter which converts and guides the reference output and sample output as the digital values synchronously with the chopping period, and a again setter which sets the gain of the variable gain amplifier depending on the reference output value from the A/D converter.

Double-beam spectrophotometer using a photodiode detector

A spectrophotometer wherein the diffraction grating is driven directly by a pulse motor and the wavelength of the monochromatic light used for measurement is calculated by a data processor from the amount of rotation of the pulse motor. The data processor is provided with an input unit for setting a parameter corresponding to the difference between the nominal and actual grating constants of the diffraction grating and so arranged as to calculate the wavelength in accordance with the nominal grating constant having been modified with the parameter set through the input unit.

A spectrophotometer system including a monochrometer which scans a sample in a sample cell with discrete wavelengths of light, and measures intensity signals of at least two discrete wavelengths of light emitted from the sample. These measured intensity signals are base-line corrected by a computer with respect to reference intensity signals at corresponding wavelengths. The computer also calculates base-line corrected intensity signals for wavelengths of light intermediate said two wavelengths of light from the intensity signals of said two respective discrete wavelengths. All base-line corrected intensity signals are stored for analysis of the sample.

Growing community of inventors

Kyoto, Japan

Toshiaki Fukuma