JPS5992318A - Spectrometry method - Google Patents

Abstract

PURPOSE:To remove the influence of the long-period and short-period variations of a light source upon spectrometry by measuring the output of the driect light of a light source and output of every wavelength before reference photometry and sample photometry, and the output of the direct light in reference photometry and sample photometry. CONSTITUTION:Light from a light source 1 enters an optical fiber 4 through lenses 2 and 3 to irradiate a reference body and body to be measured, and its reflected light is supplied from an optical fiber 5 to the photodetecting element 13 in a spectroscope 8 through lenses 6 and 7. A shutter 19 is opened and a shutter 20 is closed before reference photometry and sample photometry to make the light from the light source 1 incident to an auxiliary detector 18 and the spectroscope 8 directly through half-mirrors 14, 16, and 15, carrying out the photometry. Further, the direct light is made incident to the auxiliary detector 18 during reference photometry and sample photometry to perform the photometry. Those eight photometric outputs are calculated to perform spectrometry while removing the long-period and short-period variations of the light source 1.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention irradiates light from a light source onto a reference object. The reflected light or transmitted wave is divided into spectra and the output of each wavelength is measured, which is called reference photometry.

), the object to be measured is irradiated with light from the same light source, the reflected light 1 and the transmitted light are also separated, and the output of each wavelength is measured. This is called sample photometry. ), the present invention relates to a spectroscopic measurement method in which, for example, the color of an object to be measured is determined by comparing corresponding wavelength outputs in these two-sided lights.

Conventionally, the above-mentioned spectroscopic measurement method uses a spectrophotometer using a photomultiplier tube, but this can simultaneously measure both the reference and sample sides, but it takes a long time to measure. There was a problem.

There are also devices that use a self-scanning solid-state photodetector, but although this requires a short measurement time, it is not possible to perform sample photometry and reference photometry at the same time, so the luminous intensity of the light source is different from that during reference photometry. There is a risk that accurate measurements may not be possible due to changes during photometry, so it was necessary to compensate for fluctuations in the light source, especially for this light source.
Rogen lamps are often used, and the light source fluctuations of these lamps include long-term fluctuations with relatively long cycles accompanied by changes in spectral distribution, and short-term fluctuations with extremely short cycles that are independent of wavelength. The invention corrects for both of these variations.

Therefore, in the present invention, direct light from the light source is detected before reference photometry, and this output is set as Sor.

), this direct light is separated and detected for each wavelength, and this detection power is defined as Dλdr. ), the direct light from the light source is detected before the light from the sample 81, and this output is designated as Sos. ), this direct light is spectrally separated and detected for each wavelength, and this detection power is defined as Dλds. ), direct light from the light source is detected during reference photometry, and this output is designated as Slr. ), direct light from the light source is detected during sample photometry, and this output is designated as S's. ), Sor X5os,, Sjr
XS1. Correct long-term fluctuations and short-term fluctuations during sample photometry based on s XDλdr and Dλds.

Hereinafter, the present invention will be explained in detail based on one embodiment shown in the drawings.

Without further ado, the apparatus used in the method according to the present invention will be described. In FIG. 1, ``■'' is a light source, for example a halogen lamp. The light from this light source 1 enters the irradiation optical fiber 4 through the lens 2.3 and is irradiated onto a reference object or an object to be measured. The reflected light (transmitted light by Totake) is dispersed from the reflective optical fiber 5 through the lens 6.7, the slit 9 in the spectrometer 8, the concave mirror IO1 dispersion element II, and the concave mirror 12, and is dispersed into a self-scanning solid-state. The light is supplied to the light receiving element 13.

The self-scanning solid-state photodetector 13 has n photodiodes corresponding to each wavelength integrated in an array. It sequentially scans up to the photodiode and outputs a photoelectric conversion signal.

The light from the light source J, which is split by the half mirror 1-14 provided between the lenses 2 and 3, is guided to the spectrometer 8 by the half mirror 15 provided between the lenses 6 and 7, and is simultaneously split by the half mirror 16 and the lens I7. It is led to the auxiliary detector I8, and the auxiliary detector 1 outputs a photoelectric conversion output. 1
9.20 is the shutter, shutter 19 is half mirror 1
5 and 16, and the shutter 20 is provided between the half mirror 1
5. It is provided between the lenses 5. In the case of reference photometry and sample photometry, Id-shutter 19 is closed and shutter 2 is closed.
Open o. When the light from the shunted light source 1 is directly supplied to the spectrometer 8 (this is called direct photometry), the shutter 1
9 and close the shutter 20.

Each photoelectric conversion output of the self-scanning solid-state photodetector 13 is amplified by an amplifier 21 and then converted into a digital signal by an A/D converter 22 and stored in a memory 23. The addresses to be stored are an address signal 24a whose lower previous bit is the count output of a counter 24 which counts tarock pulses generated by the clock pulse generator 14 to scan the self-scanning solid-state light receiving element 13, and a microcomputer 25. The address signal 25a is determined by the upper previous bit supplied from the address signal 25a. The photoelectric conversion output of the auxiliary detector I8 is also amplified by the amplifier 26 and then converted to A/
It is converted into a digital signal by the D converter 27 and stored in the memory 28.
is memorized. These addresses to be stored are specified by an address signal 25b supplied from the microcomputer 25. Note that 25c is a measurement start signal for the clock pulse generator 14, 25d is a read address signal for the memory 23, and 25e is a read address signal for the memory 28.

In this embodiment, as shown in the flowchart of FIG. 3, the light source is activated at predetermined intervals (a time sufficiently shorter than the fluctuation period of the long-term fluctuation of the light source l) until the reference photometry start signal or the sample photometry start signal is input. Direct photometry is performed, n photoelectric conversion outputs are obtained from the self-scanning fixed light receiving element 13, and n Dλd are obtained by digitally converting these outputs. The output is obtained and converted into digital to obtain So, which is stored in the memory 28. These n Dλd and S
o is updated every time new light source direct photometry is performed.

When the reference photometry start signal is input, reference photometry is performed and n Dλmr and 1
5i11- is obtained and stored in the memory 23.28. Then, the So obtained by direct light metering from the light source immediately before this reference metering, which is stored in the memory 28, is
As shown in the subroutine of Fig. 4, Sor/S1
．． r is calculated, n Dsmr and 5orA4r are multiplied to obtain n Dλr, and Dλd is stored together with these Dλr as Dλdr.

The light source direct photometry is repeated as described above until the next two-sample photometry start signal is input, but when the sample photometry start signal is input, n Dλms and one S's are obtained, and the second sample photometry start signal is input. 23.28.

After that, as shown in the subroutine of FIG. 5, the So during the light source direct photometry immediately before the sample photometry in steps 2 and 4 is set to Sos, and Sos/S4. Calculate s, n 91m8 and S
o s/s 4. s, respectively, and n Dλ
Get S.

Then, let n Dλd during light source direct photometry immediately before this sample photometry be Dλds, and each corresponds to (
) Dλdr , VDλde , DλsX of the same wavelength
Calculate Dλr smell and obtain n R. These are the reflectance, transmittance, or absorption of the object to be measured relative to a reference object, and these are used to determine, for example, the color of the object to be measured. Thereafter, another measurement object is measured in the same manner, but the reference photometry only needs to be performed once at the beginning, and there is no need to perform the reference photometry again each time the measurement object changes.

In such a spectroscopic measurement method, the output D^mr of each wavelength obtained by reference photometry and sample photometry.

Dλms is the value Dλr when standard photometry and sample photometry are performed using the light source used in direct photometry performed immediately before these photometry, and DλS is the daily output of the auxiliary detector J, r, , S4s X5or, Sos. D obtained from the self-scanning solid-state photodetector 13 during direct photometry immediately before reference photometry and sample photometry, respectively.
λdr.

Since the calculation of R is performed using Dλds, Dλr, and DλS, it is possible to convert to the state in which reference photometry and sample photometry have been performed using Dλdr, and the influence of long-term fluctuations and short-term fluctuations of the light source 1 can be removed. Therefore, errors caused by long-term and short-term fluctuations of the light source, which were problems with conventional spectroscopic measurement methods using self-scanning solid-state photodetectors, can be eliminated, and the advantage of self-scanning solid-state photodetectors is that the measurement time is short. I can make the most of it.

In the above embodiment, the fiber 4.5 is used to irradiate light onto the reference object or the object to be measured, and the reflected light (or transmitted light)
was introduced into the spectrometer 8, but it is also possible to use various known optical systems that are limited to fibers. It is also possible to use a well-known structure such as using a half mirror for dividing the optical path and using a shutter or a movable mirror for switching the optical path.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an optical system used in the spectroscopic measurement method according to the present invention, FIG. 2 is a block diagram of an electric circuit used in the method, FIG. 3 is a flow chart showing the process of the method, and FIG.
This figure is a detailed flowchart of a part of the process of the flowchart of FIG. 3, and FIG. 5 is a detailed flowchart of a process different from the process shown in FIG. 4 of the flowchart of FIG. ■...Light source, 8...Spectrometer, 13.Self-scanning solid-state photodetector 1.18...Auxiliary detector, 25...Microcomputer patent applicant Yamato Seiko Co., Ltd. Agent Shimizu Tetsu and two others I Figure':X2 Figure'X3 Figure

Claims (1)

[Scope of Claims] [1] A reference photometry process in which a reference object is irradiated with light from a light source, the reflected light or transmitted light is separated, and the output Dλmr of each wavelength is measured, and the light from the light source is A sample photometry process in which the output Dλms of each wavelength is measured by irradiating the object to be measured and dispersing the reflected light or transmitted light, and before the reference photometry, the direct light from the light source is spectrally analyzed. The process of measuring the wavelength output Dλdr and also measuring the direct light from the light source without spectroscopy to obtain the output Sor, and the process of measuring the direct light from the light source without spectroscopy to obtain the output Sor, and before the sample photometry, the process of spectroscopy of the direct light from the light source to obtain its respective wavelengths. In addition to measuring the output Dλds, the output SoS is also measured by measuring the direct light from the light source without spectroscopy.
The process of obtaining the output Jr by measuring the direct light from the light source without spectroscopy during the first stage of the standard photometry, and the process of measuring the direct light from the light source without spectroscopy during the sample photometry. and the process of obtaining the output Sls and the process of obtaining the output Sls and the corresponding Dλmr
, Dλme XDλdr Dλmr in XDλds
A spectroscopic measurement method comprising a process of calculating Sl and r.