JPH0720042A - Device for spectroscopic analysis - Google Patents

Abstract

PURPOSE:To obtain a device for spectroscopic analysis which can secure sufficiently high measurement accuracy even when the ambient temperature, etc., fluctuate and can perform accurate analysis even when the device is connected to an automated line. CONSTITUTION:In a device for spectroscopic analysis provided with a light source 1 for irradiating a measuring section 30 in and from which samples to be measured can be freely put and taken out, spectroscopic means which separates a luminous flux for measurement transmitted through the section 30, and array type light receiving elements which receive the separated luminous fluxes, a switching means provided with a wavelength calibrating section 20a and reference section 20b which respectively calibrate the luminous flux into a calibrated luminous flux and reference luminous flux, intercepting means which intercepts the luminous flux for measurement, and transmitting section 20d for the luminous flux for measurement are provided. In addition, a control means which switches the switching means in order of a stage in which the luminous flux for measurement is transmitted through the section 20a at every sample measurement, stage in which the luminous flux is transmitted through the section 20b, stage in which the luminous flux is intercepted by the section 20c, and stage in which the luminous flux is transmitted through the section 20s as it is so that spectroscopic analysis can be performed while wavelength calibration is performed at every sample measurement is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recently proposed spectroscopic analysis device for analyzing components such as grains by a spectroscopic analysis method. More specifically, the present invention relates to a spectroscopic analysis device in which a sample to be measured can freely move. A light source for irradiating a measuring ray bundle to the section, a spectroscopic means for dispersing the measuring ray bundle transmitted through the measuring section or reflected from the measuring section, and an array type light receiving element for receiving the dispersed measuring ray bundle And a spectroscopic analysis device having

[0002]

2. Description of the Related Art Conventionally, in this type of spectroscopic analyzer, in a normal measurement state, a sample measurement state in which a measurement light beam transmits or reflects a sample, a reference measurement state in which a measurement light beam transmits a reference. Also, data is captured in three states, that is, in a dark state in which light does not enter the array type light receiving element, the light absorbance is obtained for each wavelength, and spectral information is obtained to analyze the component according to a specific calibration formula. I was getting results. Here, the wavelength calibration for determining the wavelength of the light entering each element of the array type light receiving element is performed at the time of shipping the product or at the time of installing the spectroscopic analyzer on site. Further, for example, an operator may calibrate each season, if necessary. In the calibration, the wavelength calibration was manually performed by setting a wavelength calibration filter in the optical path of the measuring light beam bundle and specifying the wavelength received by each light receiving element.

[0003]

However, in the above configuration, for example, when the place where the analyzer is installed is a place where the ambient temperature changes abruptly, or the supply and discharge of the sample is automated. When arranging the analyzer in the process line, it is not possible for the operator to perform wavelength calibration appropriately due to changes in environmental conditions, etc.
There was a problem in securing the measurement accuracy.

Therefore, an object of the present invention is to obtain a spectroscopic analyzer capable of ensuring sufficient measurement accuracy even with changes in atmospheric temperature and the like, and capable of performing accurate analysis even when installed in an automated line. is there.

[0005]

To achieve this object, the spectral analyzer according to the present invention is characterized in that the measuring light beam is transmitted between the light source and the spectroscopic means on the optical path of the measuring light beam. Wavelength calibration unit with a calibration filter that makes a calibration light beam bundle, a reference unit that transmits the measurement light beam bundle as a reference light beam bundle, a dark current measurement shield unit that blocks the measurement light beam bundle, and a measurement unit The switching means is provided with a cutout portion that allows the light beam to pass through as it is, and the switching means is used for each sample measurement, from the first step in which the measuring light beam passes through the wavelength calibration section to the second step in which it passes through the reference section Control means is provided for switching in the order of the description of the third step of being blocked by the dark current measuring shield and the fourth step of passing through the notch as it is, and the sample is placed in the measuring section at the fourth step. Means Only, in the spectroscopic analysis while wavelength calibration for each sample measurement. And
The action and effect are as follows.

[0006]

That is, the spectroscopic analyzer of the present invention is constituted by including switching means and control means, and the switching means is sequentially switched from the first stage to the fourth stage by the action of the control means. Then, in the first stage, the measurement light beam is transmitted through the calibration filter to be a calibration light beam, which is received by the array type light receiving element and the data required for wavelength calibration is captured. Then, following this first step, by the operation of the control means and the switching means, in the second, third and fourth steps, the reference information in the array type light receiving element, respectively,
Dark information and sample information are captured. Then, the spectroscopic analysis is performed based on the information whose wavelength has been calibrated using these pieces of information. Moreover, this measurement procedure is maintained for each measurement of each sample.

[0007]

Therefore, in the spectroscopic analyzer of the present application, the wavelength calibration that most affects the accuracy of the spectroscopic analysis is performed each time the measurement of each sample is performed. Not only is it significantly improved, but reliability is also secured. Generally, when the object to be subjected to the spectroscopic analysis is the component analysis, the second derivative value of the spectrum of the transmitted light or the reflected light at a plurality of (3 to 4) specific wavelengths is a calibration formula for determining the component analysis amount. Although the basic data is used, the accuracy of the basic data is reliably ensured by adopting the above configuration, and as a result, accurate analysis is realized. Therefore, it is possible to automatically cancel the effects of sudden changes in atmospheric temperature and aging, contamination of the container that holds the sample, deterioration of the lamp as the light source, etc., and to maintain measurement accuracy even when fully automatic operation is performed. An analytical device was obtained.

[0008]

EXAMPLE A spectroscopic analysis apparatus using cereals as a sample S, which is an example of the spectroscopic analysis apparatus according to the present invention, will be described below.

As shown in FIG. 1, the spectroscopic analysis apparatus irradiates a light source 1, a first optical system 2 for shaping a measurement light beam from the light source 1, and a measurement light beam from the first optical system 2. Sample holding part 3, a second optical system 4 that collects a measurement light beam that has passed through the sample S held by the sample holding part 3, and a measuring light that is collected by the second optical system 4. A spectroscopic analysis section 5, which is an example of a light-receiving container for spectroscopically analyzing a light bundle, is arranged along the optical axis P.

The light source 1 is composed of a tungsten-halogen bulb. The first optical system 2 includes a lens 2a that forms a bundle of rays of light directed to the sample holder 3 into a bundle of parallel rays of light, and further, between the light source 1 and the spectroscopic analyzer 5 on the optical axis P of the bundle of rays for measurement. A switching means 200 for switching this light flux to a predetermined state is provided on the spectroscopic analysis section 5 side of the sample holding section 3 in the embodiment. The switching means 200 includes a rotating disk 20 that rotates around an axis, and as shown in FIG. 2, further includes a calibration filter that includes a calibration filter that transmits a measurement light beam bundle to form a calibration light beam bundle. A portion 20a, a reference portion 20b that transmits the measurement light beam bundle to form a reference light beam bundle, a dark current measurement shield portion 20c that blocks the measurement light beam bundle, and a notch portion 20d that allows the measurement light beam bundle to pass through. Is provided in the circumferential direction. Then, as the rotary disc 20 rotates around the rotary shaft 21, the state of the transmitted light is switched to each state. Here, by controlling the number of rotations of the rotating disk 20, the time interval at which the measuring light flux crosses each part can be set arbitrarily. Now, as shown in FIG.
A pair of light rays having a peak in a pair of specific wavelength ranges (λ ₁ λ ₂ ) and a pair of peak wavelengths that are specified in advance and a pair of array type light receiving elements 7 that receive these peak wavelengths. From the positional relationship of the elements, it is possible to establish a correspondence between each element forming the array type light receiving element and the wavelength of the light received by each element.

The sample holder 3 is composed of a container 3a made of quartz glass, and the container 3a contains grains as a sample S therein. As shown in the figure, the container 3a is provided with a retreating means 30a for the measuring unit 30 through which the optical axis P of the measuring light beam bundle passes, in a state of crossing the optical axis P and in a state of being separated from the optical axis P. It is configured to move in and out freely. The second optical system 4 includes a condenser lens 4a that condenses the light beam that has passed through the sample S at the position of the entrance hole 5a of the spectroscopic analysis unit 5, and a dark box 4b that prevents harmful light from entering the optical path. It is composed of.

The spectroscopic analysis section 5 is provided with an aluminum dark box 5b adjacent to the second optical system 4, and the dark box 5 is provided.
In b, there is provided a concave diffraction grating 6 as a spectroscopic means for spectrally reflecting the incident light flux, and an array type light receiving element 7 for detecting the intensity of the light flux of each wavelength spectrally reflected. Further, between the incident hole 5a and the concave diffraction grating 6 in the measurement optical path in the dark box 5b, a reflecting mirror 8 for reflecting the incident light flux from the incident hole 5a toward the concave diffraction grating 6 is provided. It is provided. That is, the spectroscopic analysis section 5 is a polychromator type spectrometer.

The array type light receiving element 7 is fixedly installed in the light receiving element fixing portion 9 provided in the dark box 5b on the dispersion optical path of the light flux by the concave diffraction grating 6, and is made of silicon (S
i) or lead sulfide (PbS) or germanium (Ge) sensor. The detection signal from the array type light receiving element 7 is sent to the processing means 70 and processed by the processing means 70 to obtain spectrum-related information such as the processed spectrum and the second derivative value of the spectrum. Further, the control means 10 links the switching means 200 and the processing means 70 described above.

The operation sequence of the spectroscopic analyzer of the present application will be described below in itemized form with reference to FIG. The processing of the data is performed by the processing means 70 which is interlocked with the switching means 200 described above. 1 Measurement Start (Wavelength Calibration Data Collection Process-First Stage) This state is the state shown in FIG. 4A, in which the container 3a is held in a retracted state with respect to the measurement unit 30, There is nothing in 30. On the other hand, the rotating disc 20 is in a state in which the wavelength calibration unit 20a, which is the origin state, is positioned on the optical axis P. Then, when the measurement light beam is irradiated, the light beam transmitted through the wavelength calibration unit 20a becomes a calibration light beam having a peak at a pair of specific wavelengths (λ ₁ λ ₂ ). The light is received by the mold light receiving element 7, and each element can be associated with a wavelength. This is done for each sample measurement. 2 Reference Data Collection Process (Second Step) This state is the state shown in FIG. 4B, and the container 3a is held in the retracted state with respect to the measurement unit 30 as in the above process. There is nothing in the measuring unit 30. on the other hand,
The rotating disk 20 rotates so that the reference portion 20b moves to the optical axis P.
Take the state of being located above. Then, when the measurement light beam is emitted, the light beam that has passed through the reference portion 20b is made reference light by passing through a reference (frosted glass or the like) that is in the measurement state (temperature), and the reference information Rd is obtained. can get. 3 Dark Information Collection Process (Third Stage) This state is the state shown in FIG. 4C, in which the rotating disk 20 rotates and the dark current measuring shield 20c is positioned on the optical axis. Therefore, in this state, light does not enter the array type light receiving element 7, and the dark information D in the measurement state is obtained. On the other hand, the container 3 a in which the sample is filled in the container 3 a is moved to the measuring unit 30. 4. Wavelength calibration processing step After the above steps are completed, wavelength calibration is performed in the processing means 70. 5 Sample Data Collection Process (Fourth Stage) This state is the state shown in FIG. 4D, in which the container 3a is positioned in the measurement unit 30, and the measurement light flux passes through the sample. Become. On the other hand, the rotary disc 20 is rotated so that the cutout portion 20d is positioned on the optical axis P. Therefore, the sample information Sd is obtained by receiving the transmitted light that has been transmitted through the sample by being irradiated with the measurement light beam.
Can be obtained. 6 Process of calculating absorbance and other spectral data From the sample information Sd, the reference information Rd, and the dark information D obtained in the above process, the absorbance d is obtained according to the following formula. Absorbance d = log ((Rd-D) / (Sd-D)) Further, from the above-mentioned absorbance, spectrum-related information such as a spectrum and a second derivative in the wavelength region of the spectrum is obtained and output. Further, the component value of each component (water, protein, etc.) in the sample is obtained using the second derivative of the spectrum at a plurality of specific wavelengths. In this calculation, in the spectroscopic analyzer of the present application, wavelength calibration,
Since the reference measurement and the dark output measurement are performed for each measurement, the component amounts can be accurately specified. Therefore, the reliability of measurement is improved.

[Other Embodiments] (a) In the above embodiment, the tungsten-halogen bulb is used as the light source 1, but the light source 1 is not limited to this, and can be set appropriately according to the sample S and the measurement purpose. Yes, a thermal radiator (black body furnace) as a light source 1 having continuous spectrum emission in the entire infrared region, other light sources 1 such as a mercury lamp and a Ne discharge tube, a laser emitting a monochromatic light for measuring Raman scattering, etc. Can be used, and its configuration can be appropriately changed. (B) Further, in the above embodiment, the sample S
Although the analysis was carried out using the measuring light flux passing through, the reflected light may be used.

(C) In the above embodiment, the switching means is provided with the rotary disk, and each step is performed by rotating the rotary disk. However, as shown in FIG. 5, it is simply a flat member. Reference numerals 22 to 22 (wavelength calibration unit 20a, reference unit 20b, dark current measurement shield unit 20c, cutout unit 20).
d) may be provided, and the state of the measuring light beam bundle may be determined by moving the member 22 with respect to the optical axis P. (D) Further, in the above-mentioned embodiment, the sample container is moved to the measuring section in the third step, but this is merely required to realize the state where the sample S is in the measuring section 30 in the fourth step. . The means for executing this is called the leaving means.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a spectroscopic analyzer.

FIG. 2 is a diagram showing the configuration of a rotating disk.

FIG. 3 is a diagram showing a state of a calibration ray bundle.

FIG. 4 is a diagram showing a positional relationship among a light source, a sample container, a rotating disk, and a spectroscopic analysis unit in each measurement state.

FIG. 5 is a diagram showing another configuration example of the switching means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 light source 6 spectroscopic means 7 array type light receiving element 10 control means 20a wavelength calibration section 20b reference section 20c dark current measurement shield section 20d cutout section 30a exit / return means 200 switching means

Claims (1)

[Claims] 1. A light source (1) for irradiating a measuring light beam for measurement onto a measuring section (30) through which a sample (S) to be measured can freely move.
Through the measuring part (30) or the measuring part (3
0) A spectroscopic analysis device comprising a spectroscopic unit (6) for spectroscopically measuring the measuring light flux reflected from the measuring light flux, and an array type light receiving element (7) for receiving the spectroscopically measuring light flux. A wavelength calibrating unit (20) provided with a calibration filter for transmitting the measurement light flux into a calibration light flux between the light source (1) and the spectroscopic means (6) on the optical path of the measurement light flux.
a), a reference unit (20b) that transmits the measurement light beam bundle to form a reference light beam bundle, a dark current measurement shield unit (20c) that blocks the measurement light beam bundle, and the measurement light beam bundle as they are. A switching means (200) having a cutout portion (20d) for passing therethrough is provided, and the measurement light flux is transmitted through the wavelength calibration portion (20a) every time the switching means (200) performs sample measurement. From the step, the second step of passing through the reference part (20b), the third step of being blocked by the dark current measuring shield part (20c), and the fourth step of passing through the cutout part (20d) as they are. Control means for switching in the order of description (10)
A spectroscopic analysis device for performing spectroscopic analysis while calibrating the wavelength for each sample measurement by providing an exiting / retracting means (30a) for disposing the sample in the measuring section in the fourth step.