JPH02128123A - Spectroscopic photometer - Google Patents

Abstract

PURPOSE:To perform a quick measurement by varying an applied voltage of a photoelectric converter until a photoelectric conversion signal of a 0th-order diffraction light depending on an intensity of all spectroscopic wavelengths reaches a specified value or is within a specified range. CONSTITUTION:A photometer has a spectroscope 1 to vary an angle of rotation of a scattering element 1a into which is incident light from a sample sequentially with a driver 1b so that a wavelength of light emitted at an outlet slit 1e is changed sequentially and a photoelectric converter 2 which converts the light emitted at the slit to into electricity while varying sensitivity according to a size of an applied voltage to obtain a spectroscopic sensitivity characteristic based on a photoelectric conversion signal of the converter 2. Then, a computer 4 inputs a command signal to the driver 1b to emit a 0th-order diffraction light at the slit 1e with the control of an angle of rotation of the scatting element 1a. The computer 4 further makes the applied voltage of the photoelectric converter 2 change until the photoelectric conversion signal from the photo-electric converter 2 of the 0th-order diffraction light emitted at the slit 1e reaches a specified value or is within a specified range.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a spectrophotometric device, and more particularly, to a spectrophotometric device having a photoelectric converter whose sensitivity changes depending on the magnitude of applied voltage.

[Conventional technology]

A spectrometer that sequentially changes the rotation angle of a dispersion element into which light from a sample is incident using a drive device to sequentially change the wavelength of light emitted from an exit slit, and a spectrometer that photoelectrically converts the light emitted from the exit slit. Additionally, a spectrophotometric device is known which includes a photoelectric converter whose sensitivity changes depending on the magnitude of an applied voltage and obtains spectral sensitivity characteristics based on a photoelectric conversion signal of the photoelectric converter.

[Problem to be solved by the invention]

In the conventional technology as described above, the spectral sensitivity characteristics displayed on a CRT etc. are checked to prevent the photoelectric conversion signal from appearing at a low level with almost no signal change or from saturating the photoelectric conversion signal. Therefore, the magnitude of the applied voltage to the photoelectric converter was adjusted.

This 1ljlff is based on intuition, so after changing the magnitude of the applied voltage - degree, it was necessary to find the spectral sensitivity characteristics again under the new applied voltage, and if it was not suitable, it was necessary to change the applied voltage again. .

Therefore, there were problems in that the operability was poor and it took time to adjust the applied voltage.

[Means to solve the problem]

Therefore, in the present invention, the spectral bag W (
1), and a photoelectric converter (2) that photoelectrically converts the light emitted from the exit slit and whose sensitivity changes depending on the magnitude of the applied voltage, and the photoelectric converter (2) has a In a spectrophotometric device that obtains spectral sensitivity characteristics based on a photoelectric conversion signal, a command means (a third command means) for inputting a command signal to the drive device to control the rotation angle of the dispersion element and cause the O-th order diffracted light to be emitted from the exit slit. Step 2 in Figure 2
0 in the computer 4) and the applied voltage to the photoelectric converter until the photoelectric conversion signal by the photoelectric converter of the O-order diffracted light emitted from the output loss lint reaches a predetermined value or within a predetermined range. control means (
means in the computer 4 for executing steps 21, 22, 23, 24 of FIG.

[For production]

In the present invention, 0, which depends on the intensity of all spectral wavelengths,
Since the voltage applied to the photoelectric converter is changed until the photoelectric conversion signal of the next-order diffracted light reaches a predetermined value or within a predetermined range, the applied voltage can be easily and quickly adjusted without performing wavelength scanning. Since the 0th-order diffracted light depends on the intensity of all spectral wavelengths, the photoelectric conversion signal obtained by wavelength scanning will not become too small or saturated as long as the sample does not change.

[Example] The present invention will be described below based on the example shown in the drawings. FIG. 1 is a block diagram of one embodiment of the present invention;
The figure is a flowchart of the computer used in FIG.

In FIG. 1, a spectroscopic device 1 includes a dispersive element 1a, a drive device 1b that rotates the dispersive element 1a, an input optical system 1c that receives light from a sample (not shown) and guides it to the dispersive element, and a dispersive element 1a. This is a well-known system that incorporates an exit optical system 1d that guides the light from the outside to the exit point. The dispersion element la of the spectrometer 1 is rotationally controlled by a drive bag ff1b that receives control commands from the computer 4, and the wavelength of the light emitted from the exit slit 1e is sequentially changed.

The light emitted from the output loss lint 1e of the spectrometer 1 enters a photomultiplier tube 2, which serves as a photoelectric converter whose sensitivity changes depending on the magnitude of the applied voltage, and is photoelectrically converted. The photoelectric conversion signal of the photomultiplier 2 is converted into a digital signal by the A/D converter 3 and then taken into the computer 4.

The computer 4 receives various instructions from the keyboard 5, issues control commands to the driving device of the spectroscopic bag W1, causes the display 6 to display measurement results, etc., and also causes the variable voltage generator 7 to output signals to the photomultiplier 2. The control command for the applied voltage is given.

In response to a measurement start command from the keyboard 5, the computer 4 first performs a photomultiplier sensitivity setting operation according to the flowchart of FIG. That is, the computer 4 issues a control command tb to the drive device for the dispersion element 1a of the spectrometer 1 so that the 0th order diffracted light is output from the exit slit 1e (step 20). Mechanically, by simply increasing the rotation angle of the dispersion element 1a, 0
The next diffracted light can be emitted from the laser beam. More specifically, the light from the sample is specularly reflected by the dispersion element 1a, and the dispersion element 1a is rotated at an angle toward the exit slit le. The computer 4 inputs the photoelectric conversion signal of the photomultiplier 2 at that time through the A/D converter 3, and determines whether the photoelectric conversion signal is within a predetermined range.

That is, first, it is determined whether it is larger or smaller than the upper limit of a predetermined range (Stellaf 21), and if it is larger, the sensitivity of the photomultiplier 2 is lowered, and the variable voltage generator 7 is instructed to lower the voltage applied to the photomultiplier 2 by a predetermined value. A command is issued (step 22). Stelaph 21 and Stellaf 22 are repeated until the photoelectric conversion signal becomes smaller than the upper limit of a predetermined range. If the photoelectric conversion signal is smaller than the upper limit of the predetermined range, it is determined whether the photoelectric conversion signal is larger or smaller than the lower limit of the predetermined range (step 23). Steps 23 and 24 of instructing the generator 7 to increase the voltage applied to the photomultiplier 2 by a predetermined value (Stellaf 24) are repeated until the photoelectric conversion signal becomes larger than the lower limit of the predetermined range.

If the photoelectric conversion signal is larger than the lower limit in step 23, the voltage applied to the photomultiplier 2 remains unchanged and the spectrophotometry mode 2
Enter 5. In the spectrophotometry mode 25, the computer 4 selects a predetermined wavelength range (for example, 400 nm to 70 nm) necessary for measurement.
A control command is input to the drive device 1b of the spectrometer 1 to rotate the dispersion element 1a so that light with a lower limit wavelength of 0na+) is emitted from the output loss lint. And A/D converter 3
A photoelectric conversion signal from the dispersion element 1a is stored in a memory in correspondence with the wavelength set above, and a control command is input to the drive device 1b to slightly rotate the dispersion element 1a. Then, similarly to the above, the photoelectric conversion signal from the A/D converter 3 is transferred to the dispersion element 1a.
The wavelength of the light emitted from the exit slit 1e is stored in the memory in correspondence with the wavelength of the light emitted from the exit slit 1e. In this way, the rotation of the dispersion element 1a, the storage of the photoelectric conversion signal, and the rotation of the dispersion element 1a
The rotation and repeated operations are continued until light of the upper limit wavelength of the predetermined wavelength range is obtained from the output loss lint 1e.

As a result, data corresponding to the spectral sensitivity of the sample is stored in the memory, so the computer 4 reads data corresponding to the wavelength from the memory, and the horizontal axis shows the wavelength and the vertical axis shows the light intensity on the display 6. The spectral sensitivity characteristics (waveform) are displayed.

At this time, the sensitivity of Photomul 2 is set in advance using the O-order diffracted light that depends on the light intensity of all wavelengths of light from the sample, so the sensitivity can be set based on approximately the average intensity of the light intensities of all wavelengths, so the spectral It is possible to achieve a signal level that is so good that the sensitivity characteristics do not become saturated or the signal becomes so small that the position of maximum intensity is not known.

Of course, in this case, if the sensitivity is set so that the average intensity takes the maximum value that does not saturate, the maximum intensity position will not be known. It is necessary to determine the upper and lower limit values in step 23.

Generally, the upper limit is 70% for the maximum strength that does not saturate.
, the lower limit will be set at around 40%.

Also, instead of putting the photoelectric conversion signal within a predetermined range determined by the upper and lower limits, it is also possible to drive it so that it almost matches a predetermined value, but in this case, the predetermined value is the maximum intensity that does not saturate. It is sufficient to set the value to approximately 50%.

Spectral sensitivity characteristics are generally not concerned with the absolute value of intensity, but with the wavelength and waveform of the maximum intensity, so the data is normalized and the display 6 is displayed based on the normalized data. It is common to display spectral sensitivity characteristics. The vertical axis at this time represents relative spectral sensitivity. When normalization is assumed in this way, there is no need to bring the maximum intensity to just before saturation, so as mentioned above, the upper and lower limits of the predetermined range for comparing the magnitude of the photoelectric conversion signal are It is understood that it can be defined quite roughly.

Note that the drive for changing the rotation angle of the dispersion element 1a! Jl
As lb, a sine bar or a pulse motor directly connected to a dispersion element can be used.

〔Effect of the invention〕

As described above, according to the present invention, the sensitivity of the photoelectric converter is automatically set based on the intensity of the O-order diffracted light at the beginning of measurement, so not only is there no need to worry about setting the sensitivity, but the sensitivity Since the setup time is significantly reduced, rapid measurements can be made.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a flow chart of the computer 4 in FIG. 1 according to the present invention. [Explanation of symbols of main parts] 1...Spectroscope la...Dispersion element ib...Driver 1e...Output loss lint 2...Photomulti 3...・A/D converter 4...Computer 7...Variable voltage generator

Claims (1)

[Scope of Claims] A spectroscopy device that sequentially changes the rotation angle of a dispersion element into which light from a sample is incident using a drive device to sequentially change the wavelength of light emitted from an exit slit; A spectrophotometric device that obtains spectral sensitivity characteristics based on a photoelectric conversion signal of the photoelectric converter, comprising a photoelectric converter that photoelectrically converts light and whose sensitivity changes depending on the magnitude of an applied voltage, a command means for inputting a command signal to the drive device to control the rotation angle of the dispersion element and cause the zero-order diffracted light to be emitted from the exit slit; A spectrophotometric device comprising: control means for changing the voltage applied to the photoelectric converter until the photoelectric conversion signal reaches a predetermined value or within a predetermined range.