JPH08327538A - Spectral analysis measuring device - Google Patents

Abstract

PURPOSE: To provide a spectral analysis measuring device which costs less than that when an integrating sphere is used, and in which variation in quantity of light affects measuring accuracy in less than that in an integrating sphere. CONSTITUTION: This spectral analysis measuring device comprises a light source part 3, a light quantity detection means 4, and a computation means which, from the quantity of transmitted or reflected light obtained from the light quantity detection means 4, calculates the absorbance of a subject 9 to be measured, defines a component amount estimation formula based on the absorbance obtained by the application of near infrared light to the subject 9 to be measured whose amounts of components are known and on the known amounts of components, and computes the component amount estimation formula and the amounts of components of the subject to be measured. The light source part 3 comprises a light source 6 consisting of a plurality of light emission elements, a conical diffusion barrel 10 having a conical hollow part therein, opened at the bottom of the conical hollow part, provided, at its top, with an opening 12 communicated with the outside, and provided, at the conical bottom of the conical hollow part, with a diffusion plate 8 through which light is transmitted while being diffused, and a light emitting device which causes the light emission elements to emit light at need.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spectroscopic measurement device, and more particularly to a plant leaf component amount measurement device.

[0002]

2. Description of the Related Art In the prior art, there has been no simple device for directly measuring the amount of growth-related components contained in leaves. As an alternative to this, conventionally, the leaf color is compared with a color chart to estimate the amount of nitrogen, or the target leaf is irradiated with light to determine the red light amount and the infrared light amount from the transmitted light. By measuring the amount of chlorophyll contained in the leaves (chlorophyll), the amount of nitrogen was estimated from the amount of chlorophyll. Moreover, the amount of fertilizer to be applied, which is commensurate with the estimated amount of nitrogen and the growing season, was determined. Especially, as seen in rice cultivation, the subsequent fertilization timing and fertilization amount, which are judged by the estimated nitrogen content, are important points for securing the grain yield and preventing the rice from lodging.

Now, the method of comparing the leaf color of a leaf with a color chart requires not only experience, but also that the visible leaf color depends on the weather and the position of sunlight, or whether a part of a plant is seen or the whole is seen. The judgment result often differs depending on whether or not the user looks at, and also depending on the observation angle. But,
It is also a fact that the utilization rate is high due to the simple measurement method and the inexpensive color chips used.

A chlorophyll measuring device has been developed as an alternative to the color chart. The measurement principle of a typical chlorophyll meter is
As shown in FIG. 3, the light source 51 is attached to the leaf 50 to be measured.
The transmitted light is measured by irradiating light from the red light region (the light receiving element 5 which is affected by the chlorophyll component related to chlorophyll by the dichroic mirror 52).
3) The amount of transmitted light and the infrared light region that is not affected (the light receiving element 5
The chlorophyll concentration per unit area is estimated to be destroyed by measuring the transmitted light amount in 4) and obtaining the difference in the light amounts. However, in reality, the nitrogen concentration is estimated on the assumption that the chlorophyll concentration and the nitrogen concentration are in a proportional relationship, and this is used to determine the amount of fertilizer applied to plants.

By the way, the applicant of the present invention has proposed a leaf component amount measuring device for simply measuring the nitrogen amount of a plant, in Japanese Patent Application No. 6-165.
It has already been devised by 871. This will be described in detail with reference to FIG. FIG. 4 shows an optical measuring unit 60 which is a main component of the leaf component amount measuring apparatus, and includes a light emitting means 62 for irradiating the measured leaf 61 with near infrared light of an arbitrary wavelength, and a near red light emitting diode or the like. The external light emitting element 63 and the narrow band filter 64 that allows only near infrared light of an arbitrary wavelength to pass therethrough. Then, the leaf 61 to be measured is planarly sandwiched so that the leaf surface of the leaf 61 to be measured is uniformly irradiated with near-infrared light, and the transmitted light and the reflected light from the sandwiched leaf 61 to be measured are measured. Leaf holding means 66A and 66B having measurement windows 65A and 65B are provided. The measuring window 65B of the leaf holding means 66B and the light emitting means 62 are optically connected by an integrating sphere 67. That is, the light emitting means 62 is fixed to the integrating sphere 67 so as to irradiate and scatter the irradiation light inside the integrating sphere 67. Further, the integrating sphere 67 has an opening 68 communicating with the measurement window 65B and the other. An opening 70 for fixing the reflection light receiving means 69 made of a silicon photodiode is provided.

The operation of the leaf component amount measuring device having the above structure will be described. Near infrared light emitted from the light emitting means 62 is scattered in the integrating sphere 67 and is emitted from the measurement window 65B onto the surface of the leaf 61 to be measured. . Further, the light reflected by the measured leaf 61 is reflected by the integrating sphere 67.
The light is scattered inside and is received by the reflection light receiving means 69. Further, among the near-infrared light emitted to the measured leaf 61, the transmitted one is
It is received as transmitted light by the transmitted / received means 71 formed of a silicone photodiode fixed to the measurement window 65A side of the leaf holding means 66.

[0007]

In the use of the integrating sphere 67 in the above configuration, it is necessary to increase the light quantity of the light source and to ensure the measurement accuracy when the number of wavelengths used for measurement increases. There is an advantage that the light to be measured can be uniformly irradiated to the measured leaf regardless of the light emitting position. However, the integrating sphere 67 has a step of spherically processing the inside, finishing the surface of the spherical surface by gold-plating after finishing the satin processing, and the cost of manufacturing the parts is high.

In view of the above problems, the present invention simplifies the machining of the spherical surface in the case of manufacturing an integrating sphere, is lower in cost than using an integrating sphere, and has a variation in the amount of light as compared with the integrating sphere. It is a technical object to provide a spectroscopic measurement device that does not affect the measurement accuracy.

[0009]

In order to solve the above problems, the present invention provides a light source unit for irradiating an object to be measured with near-infrared light having an arbitrary wavelength, and a transmitted light or a reflected light from the object to be measured. With the light amount detection means to calculate the absorbance of the measured object from the transmitted light amount or the reflected light amount obtained from the light amount detection means, when the near-infrared light is irradiated to the measured object whose component amount is known in advance. A spectrometric measuring device comprising a component amount estimation formula based on the absorbance and the known component amount, and a computing means for computing the component amount of the measured substance by the component amount estimation formula and the absorbance of the measured substance. The light source unit includes a light source composed of a plurality of light emitting elements, a conical hollow portion inside, a bottom portion of the conical hollow portion opened, and an opening communicating with the outside at the apex. The light spreads at the bottom of the conical hollow part. While comprising a conical diffuser cylinder provided with a scattering plate that transmits the light, and a light emitting device for appropriately causing the light emitting element to emit light, the conical diffuser cylinder transmits the light emitted by the light emitting element through the scattering plate at the cone bottom. The conical diffusion cylinder was positioned so as to irradiate the object to be measured through the opening at the apex.

The plurality of light emitting elements may be provided on a circumference centered on the conical axis of the conical diffusion cylinder.

[0011]

According to the spectroscopic analysis measuring device of the present invention, the near-infrared light having an arbitrary wavelength relating to the component of the measured object is irradiated to the measured object, and the transmitted light or the reflected light of the measured object is received. Each light quantity is obtained, and the absorbance of the object to be measured at the wavelength is obtained from each light quantity. Then, the obtained absorbance is substituted into a predetermined component amount estimation formula of the measured object, and the component amount is directly calculated nondestructively.
The component amount estimation formula is calculated by multiple regression analysis by the absorbance when the measured amount of the component to be measured is irradiated with near-infrared light of a specific wavelength, and the actual component amount of the measured amount of the component to be measured. It was done.

The light source unit for irradiating the object to be measured with near infrared light irradiates the object to be measured with light from a plurality of light emitting elements in the light source unit. The light emitted from the plurality of light emitting elements is
A specific wavelength in the near infrared region is converted by a narrow band filter or the like and is incident on the scattering plate. Within the thickness of the scattering plate, light repeatedly diffuses and transmits, and the light diffuses and loses directivity. Then, the light having lost the directivity emitted from the scattering plate is next incident on the inside of the conical diffusion cylinder, and inside the conical diffusion cylinder, the light is further reflected in the space surrounded by the conical diffusion cylinder and the scattering plate. -Repeated diffusion, and the light is incident on the light amount detecting means through the opening portion at the top. At this time, the light is reflected / diffused once or plural times by the conical diffusion cylinder inclined in a conical shape and reaches the light amount detecting means through the opening portion, so that the light amount of the light source is not reduced, and the light intensity is almost the same as that of the integrating sphere. The object to be measured can be uniformly irradiated.

Further, since the plurality of light emitting elements are provided on the circumference centered on the conical axis of the conical diffusion cylinder, when a plurality of light emitting elements used for measurement are provided to ensure measurement accuracy. In addition, the distances between the light emitting elements having different wavelengths and the cone axis of the conical diffusion cylinder are equal, and the light from any of the light emitting elements can be uniformly applied to the measured object.

[0014]

[Examples] As a preferred example of the present invention, a description will be given by taking as an example a spectroscopic analysis measuring device that irradiates a leaf with near-infrared light and measures and absorbs the absorbance and nitrogen, which is a component obtained from the absorbance. To do. FIG. 1 is a side sectional view of a main part of the portable spectroscopic analysis measurement device 1. In FIG. 1, a light source unit 3 is provided in the lower main body 2, and a photodiode 5 as a light amount detecting means 4 is provided in the upper portion. The light source unit 3 is provided with LEDs 6 which are a plurality of light emitting elements having different wavelength peaks on the same circumference, and each LED 6 is provided with a narrow band filter 7 having a different wavelength band. The wavelength band is 600 nm to 1100 nm, and from this wavelength band, the narrow band filter 7 having an arbitrary specific wavelength related to the component to be obtained is selected. The light emitted from each LED 6 becomes a light of a specific wavelength by the narrow band filter 7, and enters the scattering plate 8 through which the light passes. This scattering plate 8
Is provided perpendicularly to the optical axis so that the light rays of each LED 6 enter substantially vertically, and is formed in the shape of a circular frosted glass. The scattering plate 8 has a polished surface on either the LED 6 side or the DUT 9 side. Further, polished surfaces may be formed on both sides of the LED 6 side and the DUT 9 side. When light enters the scattering plate 8, the light diffuses within the plate thickness of the diffusion plate 8 and loses directivity. The light emitted from the scattering plate 8 and having lost its directivity then enters the conical diffusion cylinder 10. The conical diffusion cylinder 10 has a hollow conical shape,
Is fixed to the bottom, and an opening 12 is formed at the top and an inner wall is formed on the scattering wall 11 so that the light emitted from the scattering plate 8 is condensed toward the DUT 9. The scattering wall 11 is preferably made of, for example, pure aluminum, or the aluminum may be subjected to a satin finish. In the conical diffusion cylinder 10, the light is repeatedly reflected and diffused in the space surrounded by the scattering wall 11 and the scattering plate 8 and exits from the opening 12 and enters the light amount detecting means 4 through the transparent glass plate 13. . The light amount detecting means 4 is fixed to the light source section 3 at an arbitrary interval, and more specifically, is fixedly provided between the light source section 3 and the transparent glass plate 13 of the light source section 3 with an interval into which a leaf 9 to be measured can be inserted. There is.

Further, an upper lid 14 is provided on the outer periphery of the upper portion of the light quantity detecting means 4, and an arm 15 extending from the upper lid 14 is pivotally supported by a fulcrum 16. Further, a push button 17 that is loosely fitted to the main body 2 and pushes up the arm 15 of the upper lid 14 is provided, and a coil spring 18 that biases the push button 17 in the opposite direction is provided. The push button 1 is attached to the main body 2 facing the push button 17 with the arm 15 in between.
A switch 19 is provided for detecting that the 7 has been pushed down.

Next, a block diagram of the spectroscopic analysis measurement device 1 will be shown and described with reference to FIG. The transmitted light amount of the sample leaf 9 to be measured detected by the measurement unit including the light source unit 3 and the light amount detection means 4 is converted into an analog signal by the photodiode 5 and is transmitted to the analog board 20. The light source unit 3 is provided with a light emitting device 21 for the LED 6. On the analog board 20, A / from analog to digital signal
D conversion or V / F conversion from voltage to frequency is performed. The converted signal is input to the CPU board 23 including the operation of the arithmetic and control unit via the I / O board 22. On the I / O board 22, a liquid crystal display LCD 24 for displaying measurement results, calculation results or operation instructions, a keyboard 25 for inputting and operating initial data, and a RS232C connection port 2 for inputting / outputting data to / from an external device.
6 and switches are provided. These CPU boards 2
3 and the I / O board 22 are connected so that power is supplied from the power board 27. Further, the printer 29 is connected to the CPU board 23 via the printer I / F board 28.

The spectroscopic analysis measurement device 1 configured as described above
The action of will be described below. First, a reference sample having a known component amount is inserted into the spectroscopic analysis measurement device 1 in advance, and the measurement is performed. In the CPU board 23, the absorbance of the reference sample and the actual component amount of the reference sample when irradiating near infrared light are calculated. A component amount estimation formula is calculated. Then, this is stored in the CPU board 23 having the function of the storage device.

Next, when the reference sample is taken out from the spectroscopic analysis measurement device 1, the sample leaf 9 to be measured is inserted and the power is turned on, a light emission signal is sent from the CPU board 23 to the light source section 3 via the light emission device 21. Then, the plurality of LEDs 6 in the light source unit 3 irradiate light toward the sample leaf 9 to be measured. The light emitted from each LED 6 becomes a light of a specific wavelength in the near-infrared region by the narrow band filter 7, and enters the scattering plate 8 through which the light passes. Within the thickness of the scattering plate 8, light is repeatedly diffused and transmitted, and the light diffuses and loses directivity. The light emitted from the scattering plate 4 and having lost its directivity then enters the conical diffusion cylinder 10. In the conical diffusion cylinder 10, the light is further reflected and diffused in the space surrounded by the scattering wall 11 and the scattering plate 8 and enters the light amount detecting means 4 from the transparent glass plate 13. At this time, the light that has entered the conical diffusion cylinder 10 is diffused by the diffusion wall 11 that is inclined in a conical shape.
Since the light reaches the light amount detecting means 4 through the opening 12 after being reflected and diffused once or a plurality of times, the light amount of the light source is not reduced and the sample leaf 9 to be measured is uniformly irradiated to the same extent as the integrating sphere.

When the sample leaf 9 to be measured is irradiated with light,
The transmitted light or the reflected light is received by the photodiode 5, and the received light signal is transmitted to the analog board 20 for A / D conversion. On the analog board 20, A / D
It is converted and then input to the CPU board 23 including the operation of the arithmetic and control unit via the I / O board 22. CP
In the U board 23, the light transmittance or absorbance is calculated from the transmitted light or reflected light of the sample leaf 9 to be measured.

When the absorbance of the sample leaf 9 to be measured is calculated in this manner, the absorbance is substituted into the component quantity estimation formula stored in advance, and finally the ingredient quantity required by the operator is calculated. .

The CPU board 23 may be provided with a light source lighting routine for repeating lighting of each LED 6 for a certain time at a certain interval. In this light source lighting routine, the LEDs 6 having different wavelength peaks are respectively lit, and the amount of transmitted light of the measured sample leaf 9 is measured for each wavelength. As a result, the measurement accuracy of the amount of transmitted light of the sample leaf 9 to be measured is improved, and further the measurement accuracy of the absorbance of the sample leaf to be measured is improved.

[0022]

As described above, according to the spectroscopic analysis measuring device of the present invention, the light source section includes a light source composed of a plurality of light emitting elements and a conical hollow portion inside thereof. A conical diffusion cylinder provided with an opening for opening the bottom and communicating with the outside at the apex, and a conical diffuser for transmitting light while diffusing light at the conical bottom of the conical hollow portion, and light emission for appropriately emitting the light emitting element Since the conical diffuser is positioned so that the light from the light emitting element passes through the scatter plate at the bottom of the cone and irradiates the DUT from the opening at the apex of the conical diffuser, the scatter plate When light is incident on, the light diffuses within the thickness of the scattering plate and loses directivity.
When the light enters the conical diffusion cylinder, the light is reflected / diffused once or plural times by the conical diffusion cylinder inclined in a conical shape and reaches the light amount detection means from the opening, so that the light amount of the light source is not reduced, It is possible to uniformly irradiate the object to be measured with light at the same level as the integrating sphere. Further, the machining of the spherical surface in the case of manufacturing the integrating sphere has been simplified, and it has become possible to manufacture it at a lower cost than using the integrating sphere.

Further, since the plurality of light emitting elements are provided on the circumference centered on the conical axis of the conical diffusion cylinder, when a plurality of light emitting elements used for measurement are provided in order to ensure measurement accuracy. In addition, the distances between the light emitting elements having different wavelengths and the cone axis of the conical diffusion cylinder are equalized, and the light from any of the light emitting elements can be uniformly applied to the object to be measured.

[Brief description of drawings]

FIG. 1 is a side sectional view of a spectroscopic analysis measurement device of the present invention.

FIG. 2 is a block diagram of a spectroscopic analysis measurement device.

FIG. 3 is a schematic diagram showing a conventional representative chlorophyll meter.

FIG. 4 is an optical measuring unit of a conventional component amount measuring device.

[Explanation of symbols]

 1 spectroscopic analysis measuring device 2 main body 3 light source section 4 light amount detecting means 5 photodiode 6 LED 7 narrow band filter 8 scattering plate 9 DUT 10 conical diffusion barrel 11 scattering wall 12 opening 13 transparent glass plate 14 upper lid 15 arm 16 fulcrum 17 Push Button 18 Coil Spring 19 Switch 20 Analog Board 21 Light Emitting Device 22 I / O Board 23 CPU Board 24 Liquid Crystal Display LCD 25 Keyboard 26 Connection Port 27 Power Board 28 I / F Board 29 Printer

Claims (2)

[Claims] 1. A light source unit for irradiating an object to be measured with near-infrared light of an arbitrary wavelength, a light amount detecting means for receiving transmitted light or reflected light from the object to be measured, and a transmission obtained from the light amount detecting means. While calculating the absorbance of the object to be measured from the amount of light or the amount of reflected light, the component amount estimation formula by the absorbance and the known amount of the component obtained when the object to be measured whose component amount is known in advance is irradiated with the near infrared light Which is a spectroscopic analysis measuring device comprising a calculation means for calculating the component amount of the object to be measured based on the component amount estimation formula and the absorbance of the object to be measured, wherein the light source section comprises a plurality of light emitting elements. A light source and a conical hollow part inside are opened, and the bottom part of the conical hollow part is opened and an opening communicating with the outside is provided at the apex, and the conical hollow part of the conical hollow part transmits light while diffusing. A conical diffusion cylinder with a scattering plate The conical diffusion cylinder irradiates the object to be measured from the apex opening of the conical diffusion cylinder by transmitting the light generated by the light emitting element through the scattering plate at the bottom of the conical diffusion cylinder. A spectroscopic analysis measuring device characterized by being positioned as described above. 2. The spectroscopic analysis measurement device according to claim 1, wherein the plurality of light emitting elements are provided on a circumference centered on a conical axis of the conical diffusion cylinder.