JPS5928247B2 - Automatic wavelength selection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic wavelength selection device, and particularly to an automatic wavelength selection device that is effective when applied to an atomic absorption spectrometer.

In general, 1900 to 9000 for atomic absorption spectrometers
It is constructed so that wavelengths in the range A can be analyzed, and a diffraction grating is used as the analysis means, and the wavelength range is covered by rotating the diffraction grating by about 500 angles.

Therefore, high precision is required in selecting the angle of the diffraction grating. Conventionally, when selecting the angle of the diffraction grating, the angle of the diffraction grating was rotated until it was close to the desired wavelength, and the angle of the diffraction grating was finely adjusted by manually rotating the operating handle while visually checking the output from the detector. A method was adopted in which the maximum peak position of the output obtained from the detector was detected by making adjustments. However, this method is extremely complicated, and when there are many types of substances to be analyzed, this complexity becomes extremely complicated.
This became extreme and was inconvenient in terms of time and labor.

In view of the above points, the present invention has been made to solve such problems and eliminate such drawbacks.The purpose of the present invention is to automatically and extremely accurately measure the wavelength to be measured using a simple configuration. It is an object of the present invention to provide an automatic wavelength selection device that can make a great contribution to the automation of substance analysis using an atomic absorption spectrometer and can also completely perform remote analysis.

In order to achieve such an object, the present invention provides a pulse motor that meshes with the gears of a rotary table having a vertically fixed diffraction grating at the center and whose rotation is controlled by a computer, and a pulse motor that detects the rotation of the rotary table. a potentiometer for inputting the output of the filter into the computer; 5 a photoreceiver having a sensitivity capable of receiving the light from the diffraction grating and identifying the spectrum in the spectral range; a detector for detecting an absorption line or an emission line, converting it into an electric signal and inputting it to the computer, and feeding back the rotation angle of the rotary table obtained by the detector to the pulse motor. , the rotation angle of the rotary table can be adjusted to the spectral position.

Embodiments of the present invention will be described in detail below based on the drawings.

The figure is a configuration diagram showing an outline of an embodiment of the present invention, and shows only the parts necessary for explanation.

In the figure, the reference numeral 1 indicates a rotary table (hereinafter referred to as
(referred to as a turntable), and there are two gears on its outer circumferential surface.
is formed.

A gear 2 of the turntable 1 is meshed with a gear attached to a rotating shaft of a pulse motor 3 for wavelength detection and a multi-rotation potentiometer 4 for wavelength detection. A diffraction grating 5 is fixed to the center of the turntable 1. On the other hand, what is indicated by reference numeral 6 is the device casing, and the light rays 8 that enter the device casing from an opening 7 formed in a part of the device casing 6 are converted into parallel rays by a concave reflecting mirror 9. The light enters the diffraction grating 5, is decomposed into spectra by the diffraction grating 5 having a predetermined resolution, and enters another concave reflecting mirror 10.

Here, this concave reflecting mirror 10 constitutes a light receiver having a sensitivity capable of receiving the light from the diffraction grating 5 and identifying its spectrum in the spectral range. The spectrum converted into a parallel beam by the Q concave reflecting mirror 10 passes through the slit 11 and is received by the detector 12. This detector 12 detects the presence of absorption lines in the spectrum based on the density of light,
This is converted into a voltage value as an electric signal, which is manually input to the amplifier 13. The output from the detector 12 amplified by the amplifier 13 is input to an indicator 14 so that the output state can be visually confirmed.

The output signal of the detector 12 amplified by the amplifier 13 is also input to the converter 15, and converted into an electrical signal that can be input to a computer 16 that calculates various information.

The output signal from the potentiometer 4 is also input to the converter 15, and is input to the computer 16. On the other hand, computer 1
The control signal from 6 is sent to the pulse motor 3 via a converter 15.
The system is configured to provide feedback to

Next, the operation of this embodiment configured as above will be explained.

First, as mentioned above, in this embodiment configured as described above, the rotation angle of the turntable 1, that is, the rotation angle of the diffraction grating, and the output of the potentiometer 4 are determined in advance so as to correspond to each other.

Therefore, the configuration is such that it can be clearly determined from the output from the potentiometer 4 which substance the wavelength is currently being measured. For example, if you are trying to measure the analytical line of silver, the absorption line is 328
It is known that this appears at the positions of 0.7λ and 3282.8λ.

Therefore, the pulse motor 3 is rotated by a control signal from the computer 16 to rotate the turntable 1, that is, the diffraction grating 5, and the diffraction grating 5 reaches a position where it detects the silver absorption line. Whether or not the turntable 1 is at the desired position, that is, the position corresponding to the absorption line of silver, can be detected by the output of the potentiometer 4. When the turntable 1 rotates to the corresponding output position, the control from the computer 16 is activated. The rotation of the pulse motor 3 is stopped by the signal, and the rotation of the turntable 1 is also stopped. On the other hand, since the output signal from the detector 12 is input to the computer 16, it is determined whether the rotational position of the diffraction grating 5 is correctly detecting the absorption line of silver. It is determined whether or not is at the peak position.

Then, if it becomes clear that the judgment result is not in the correct position, the computer 16 gives a control signal for forward or reverse rotation to the pulse motor 3 to rotate the turntable.
Rotate the diffraction grating 5 to the correct position. Then, the content of the substance called silver is measured based on its absorption state. As is clear from the above description, according to the present invention, a light receiver is provided with a sensitivity that can receive light from a diffraction grating and identify its spectral range in a spectral range, and the rotation can be controlled by signals from a computer. A diffraction grating is placed on a turntable that is rotated by a pulse motor, and the rotation angle of the turntable is detected by a potentiometer and inputted to a computer. By inputting the output signal from the detector that detects absorption lines from the vector into a computer and comparing it with the output signal from the potentiometer, a rotation command for fine adjustment is given to the pulse motor. Because it is configured to provide feedback, the wavelength to be measured can be automatically selected, greatly contributing to the automation of material analysis using atomic absorption spectrometers and making remote analysis completely possible. It has excellent effects.

[Brief explanation of the drawing]

The figure is a block diagram showing an outline of an embodiment of the present invention. 1...turntable, 2...gear,
3... Pulse motor, 4... Potentiometer, 5... Diffraction grating, 6... Device housing, 7... Opening Part, 8... Ray of light,
9, 10...Concave reflecting mirror, 11...Slit, 12...Detector, 13...Amplifier, 14...Indicator , 15;...converter, 16...computer.

Claims (1)

[Claims] 1 In a device in which a wavelength is selected by rotating a rotary table with a rotating grating vertically fixed at the center and the rotation angle of the rotary table is adjusted to correspond to the refraction angle of each wavelength, a device that meshes with the gears of the rotary table a pulse motor whose rotation is controlled thereby, a potentiometer which detects the rotation of the rotary table and inputs its output to the computer, and a light receiver having a sensitivity capable of receiving light from the diffraction grating and identifying its spectrum in the spectral range. a detector that detects a specific absorption line or emission line in the spectrum resolved by the diffraction grating, converts it into an electrical signal, and inputs it to the computer, An automatic wavelength selection device characterized in that the rotation angle of the rotary table is fed back to the pulse motor so that the rotation angle of the rotary table can be matched to a spectral position.