JPS593329A - Wavelength reading device of spectroscope - Google Patents

Abstract

PURPOSE:To facilitate control with a simple constitution, by generating a wavelength correction signal when a spectroscope emits light of set wavelength, setting the counted value of a wavelength counting means to a certain number N, and correcting the wavelength of light emitted from the spectroscope in accordance with it. CONSTITUTION:Drive pulses generated from a drive circuit 10 for driving a motor 1 are used as pulse interval pulse signal 40, and the count value of an addition or subtraction counter 60 is added or subtracted in accordance with rotation of the motor in the positive or negative direction. The prescribed wavelength lambdac to be first set in the counter 60 is obtained as a value corresponding to a switch 22 by measuring a known line spectrum or the like. This value Nc corresponding to lambdac is set in a correction wavelength setting and storing device 70.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spectrometer used in a spectrophotometer, and more particularly to a wavelength reading device for a spectrometer.

Conventionally, to display the wavelength of a spectrometer, a scale disk or mechanical counter linked to a mechanical wavelength drive system was often used, but the installation position of these displays was limited by the linkage mechanism. At the same time, prompt display was impossible. Further, there were other problems such as the inability to extract the wavelength signal as an electrical signal. On the other hand, with the spread of digital technology in recent years, a method has been proposed in which wavelength pulses generated from a wavelength drive device at regular wavelength intervals are counted by an adder/subtractor counter, thereby solving the above problems. For example, Japanese Patent Application No. 126906 of 1970 falls under this method. According to this method, wavelength forward pulses and wavelength reverse pulses generated from a wavelength drive device at fixed wavelength intervals are controlled by an adder/subtractor. By counting, the absolute value of the wavelength is always maintained.

On the other hand, for the absolute value of the wavelength, a switch, etc. is installed at a certain position on the wavelength drive mechanism, such as a sine bar mechanism, and the drive mechanism activates the switch, etc. when the spectrometer reaches a certain wavelength. is set to . The output of this switch and the like when activated serves to set the addition/subtraction counter to a value corresponding to the wavelength of the spectrometer. In this way, when the spectrometer is turned on, the addition/subtraction counter is automatically set, and the value corresponding to the wavelength of the light to be selectively emitted from the spectrometer is always read, and the value can be held and output. becomes.

However, the accuracy of the wavelength read and held by the addition/subtraction counter depends on whether or not the counter set pulse generated by the switch etc. is generated at a position that matches the wavelength of the counter set value. With the switches and the like provided in the above-mentioned sign bar mechanism, the mounting changes depending on the position, and high accuracy cannot be expected. That is, improvement in wavelength accuracy cannot be expected.

This was improved by the technology disclosed in Japanese Patent Application No. 126906 of 1970, which uses a switch installed in the sine bar mechanism and a photo interrogator that detects the rotation angle of the feed screw to calculate the logical product of both. A complicated set pulse generation means such as a 3D set pulse generator is used. Note that the wavelength of the spectrometer has elements that change over time, so it is necessary to adjust it in a timely manner, but if the set pulse generation means is complicated in this way, adjustment is likely to be difficult. Furthermore, if it is difficult to set the adjustment position, it takes a lot of time and has the drawback of reducing measurement efficiency.

The present invention solves the above-mentioned drawbacks of the prior art, enables easy adjustment with a relatively simple mechanism, and enables accurate wavelength reading, as well as the ability to store and output wavelength spectrometers. The purpose is to provide a reading device, and its features include a wavelength calibration signal generation means that generates a signal when the spectrometer reaches a set wavelength, and the wavelength calibration signal is used to calculate the count value of the wavelength counting means. By setting a certain value N, the count value of the wavelength counting means is calibrated to a value corresponding to the wavelength of the output light of the spectrometer, and the N value is given by the calibration wavelength setting means that can be set by the operator. The reason lies in the fact that it is structured as follows.

FIG. 1 is a block diagram of a wavelength reading device for a spectrometer, which is an embodiment of the present invention. 1 is motor, 10 is motor 1
In the drive circuit that rotates the
1 to rotate the feed screw 12. This feed screw 1
A slider 13 is screwed into the slider 2, and the tip of a lever 14 that rotates around a rotation shaft 15 is in contact with the left side surface of the slider 13. Such a mechanism is generally called a one-sided wavelength drive device, and the rotation of the feed screw 12 is proportional to the rotation of a lever 14 to which a diffraction grating 16, which is a dispersion element, is attached. That is, the wavelength extracted from the spectrum a30 is scanned in proportion to the rotation angle of the feed screw 120.

A signal indicating the wavelength of light extracted from the spectrometer 30 can be expressed as a signal indicating the lateral position of the slider 13 or a rotation angle of the feed screw 12.

A protrusion 21 is attached to the slider 13, and the spectrometer 3
When the wavelength λ of the light taken out from 0 becomes the set wavelength λC,
That is, the moving distance X of the slider 13 is the value x corresponding to λC.
c, the protrusion 21 activates the switch 22.

The actuation signal of this switch 22 is sent as a wavelength calibration signal 50 to the addition/subtraction counter 60, and the counted value is set to a constant value.

The constant value set in this addition/subtraction counter 60 is the calibration wavelength setting, a value set and held in the memory 70, and λC
is a constant value NC corresponding to . Calibration wavelength setting/memory device 7
0 is a group of switches, for example, and the position of the switch 22 in a part of the sine bar is adjusted to determine the NC.

On the other hand, the addition/subtraction counter 60 adds or subtracts the wavelength interval pulse signal 40 applied from the drive circuit 10. Further, the drive circuit 10 controls the rotation of the motor 1 and generates one wavelength interval pulse 40 every time the motor 1 rotates by a certain angle.

This constant rotation angle of the motor 1 corresponds to the rotation angle of the feed screw 12 when the output light of the spectroscope 30 changes by a constant wavelength interval Δλ.

To explain in more detail, for example, if the motor 1 is a pulse motor and is driven by a drive pulse generated from the drive circuit 10, then the drive pulse or a pulse proportional to it is used as the wavelength interval pulse signal 40, and the motor 1 is The wavelength interval pulse 40 is added to or subtracted from the count value of the adder/subtractor 60 depending on whether the rotation is in the direction or in the opposite direction. Therefore, the count value corresponding to the constant wavelength λC initially set in the addition/subtraction counter 60 is
Since a value corresponding to the amount of change in the wavelength of the emitted light is added or subtracted, the count value of the counter 60 is always equal to the value of the spectrometer 3.
This will accurately indicate the wavelength of the output light of 0.

Whether the counted value of the addition/subtraction counter 60 accurately represents the output wavelength of the spectrometer 3° depends on the mounting position that determines λC of the switch 22 and the value Nc held in the calibration wavelength setting/memory unit 70. Depends on what you're doing. Assume that the pitch of the feed screw 12 is 0.5 mm, and the wavelength width that changes per rotation is lQnm, as values commonly used. Further, it is possible to install the switch with an accuracy of about 22 times, but in this case, the wavelength calibration pulse will have an error of 20 nm with respect to λC.

In conventional devices, accuracy is improved by simultaneously detecting the rotation angle of the feed screw to reduce the above-mentioned errors, and by making careful adjustments to reduce the errors in mounting the switch 22. I was letting it happen. In this embodiment, the value of λC is determined by measuring a known bright line spectrum, etc. and finding the wavelength corresponding to the switch 22 position, and the value NC corresponding to λC is set in the calibration wavelength setting/memory device 7o. Particularly, the mounting of the switch 22 allows correct initial setting of the addition/subtraction counter 6o regardless of accuracy.

Regarding the wavelength accuracy, apart from the accuracy of mounting the switch 22, there is also the reproducibility when the switch 22 is actuated. Normally, the reproducibility of the same switch itself is on the order of several μm in terms of operating distance, and considering the above example, Q
, lnm or less wavelength accuracy can be obtained. Also,
The wavelength of the spectrometer 30 itself has the property of causing changes over time due to temperature, vibration, etc., and in the conventional device, such changes over time were corrected by adjusting the position of the switch 22. However, in the apparatus of this embodiment, it is only necessary to carry out the calibration growth setting/storage unit 700 set as described above, so correction is easy.

This calibration wavelength setting/memory device 70 is not required for the additional several digits of the adder/subtractor 60, and can be constructed at low cost if it is provided only for the lower digits. That is, the value of the upper digit of the adder/subtractor 60 is always set to a constant value by the wavelength calibration pulse 50, and the value set in the calibration wavelength setting/memory unit 70 is loaded into the F digit. In this case, the range of the lower digits is determined by taking into account the mounting error of the switch 22.

That is, in the above example, it corresponds to a wavelength of 20 nm.

In the wavelength reading device of a spectrometer of this embodiment, the wavelength position detecting means provided in the sine bar structure etc. is simplified in terms of accuracy by using only the above-mentioned switch, for example, and the output of this wavelength position detecting means is simplified. The value itself corresponding to the wavelength set in the addition/subtraction counter is set =f, and
By setting the value using a known emission line spectrum or the like, it is possible to easily adjust with a simple mechanism and to read and output an accurate wavelength.

FIG. 2 is a block diagram of a wavelength reading device according to another embodiment of the present invention, and the same parts as in FIG. 1 are labeled with the same signals. In this case, a computer 80 is connected to the calibration wavelength setting/storage unit 70 and the drive circuit IO, and the calibration wavelength setting/storage unit 70 holds the digital value sent from the computer 80 as a register or the like. The output side thereof is connected to an addition/subtraction counter 60. The value NC in the calibration wavelength setting/storage unit 70 is set from the computer 80 to the calibration wavelength setting/storage unit 70 by an operator inputting the calibration value NC using an input means such as a keyboard that is normally provided in the computer. 1st shift is sent and set.

If a non-volatile register such as a C-MO8 element is used as the calibration wavelength setting/storage unit 70, the trouble of setting the register each time the apparatus is started can be eliminated, and the need for correction of secular changes can be reduced. In addition, an addition/subtraction counter 60, a calibration wavelength setting/memory device 70
It is also possible to configure it using a part of the storage device or register in the computer 80, and the effect is the same.

Furthermore, when the computer 80 is used in this way,
Automatic wavelength calibration can be performed using emission line spectra of known wavelengths. Each bright line of a mercury lamp and 65 of a deuterium discharge tube
Controlling the drive circuit 1o by the computer 80 using the 6.1 nm emission line spectrum, automatically scanning the vicinity of the emission line, detecting the peak position of the emission line spectrum, and using it for wavelength calibration of the spectrometer is known, for example, from the Japanese Patent Publication Show. No. 38030 of 1950.

USP, No. 4,203,669 Shizuka #'L"?
Neil. In FIG. 2, the operations of the switch 22, addition/subtraction counter 60, motor 1, drive circuit 10, and calibration wavelength setting/memory device 70 are the same as in FIG.

From the number of driving pulses at the peak at of the known bright line spectrum obtained in this way, the number of driving pulses at the position where the switch 22 is activated, the wavelength shifting source per pulse, and the wavelength region of the known bright line spectrum. , switch 2
The computer 80 calculates the wavelength λC at the position where 2 operates.
The calibration value N C corresponding to the calculated power υ and λC is sent to the calibration wavelength setting/storage unit 70 .

In the example of FIG. 2, the addition/subtraction counter 6 is used as in the example described above.
The upper 8 pits of 0 are always a fixed value (10100101 in binary notation in this figure), and the upper 8 pits are configured so that the values of the calibration wavelength setting/memory device 70 are respectively loaded by the wavelength calibration signal 50. .

The wavelength reading device of this embodiment does not require any adjustment of the mounting position of the switch, unlike conventional devices, and
This has the effect of significantly improving accuracy.

As described above, the wavelength reading device for a spectrometer of the present invention has the advantage that it has a simple configuration, is easy to adjust, and can accurately read the wavelength of the spectrometer and hold and output the value.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a wavelength reading device for a spectrometer which is one embodiment of the present invention, and FIG. 2 is a block diagram of a wavelength reading device which is another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Motor, IO... Drive circuit, 11... Gear system, 12... Feed screw, 13... Slider, 14...
... Lever, 15 ... Rotation shaft, 16 ... Diffraction grating,
21...Protrusion, 22...Switch, 30...Spectroscope, 4o...Wavelength interval pulse, 45...Forward/reverse signal,
5o... Wavelength calibration signal, 60... Addition/subtraction counter, 70
...Calibration wavelength setting/memory device, l Otsu 75 Chi 1st ¥-2nd 2nd

Claims (1)

[Claims] 1. A spectrometer having a light dispersion element that separates incident light in relation to growth, and a wavelength drive that rotates the light dispersion element to perform wavelength scanning of the light emitted from the spectrometer. and a wavelength counting means for adding pulses generated at regular wavelength intervals during scanning of the wavelength driving means when the wavelength increases, and subtracting the pulses when the wavelength decreases; A wavelength calibration signal generating means is provided that generates a signal when the wavelength reaches a set wavelength, and by setting the count value of the wavelength counting means to a certain value N by the wavelength calibration signal, the count value of the wavelength counting means can be adjusted. It is calibrated to a value corresponding to the wavelength of the light emitted from the spectrometer, and
A wavelength reading device for a spectrometer, characterized in that the N value is configured to be given by a calibration wavelength setting means that can be set by an operator. 2. The wavelength of the spectrometer according to claim 1, wherein some digits of the N value are predetermined constant values, and other digits are values given by the calibration wavelength setting means. reading device. 3. A patent claim in which the calibration wavelength setting/storage device is a group of switches that allows the operator to confirm in advance the wavelength of the light emitted from the spectrometer at the position where the wavelength calibration signal is generated and then set the wavelength value. A wavelength reading device for a spectrometer according to item 1.