JPH08320305A - Measuring method of concentration distribution of dissolved substance - Google Patents

Abstract

PURPOSE: To obtain a measuring method in which a change in the concentration distribution of a dissolved substance soaked into a substance can be displayed as an image by a method wherein a sensing part is formed on one face of a semiconductor substrate and probing light is made to irradiate the semiconductor substrate. CONSTITUTION: For example, the cut face 27a of an apple 27 which has been cut into halves is brought into contact with a sensing face (an Si3 N4 layer) 14 on a sensing part 11. A counter electrode CE and a reference electrode RE are inserted into the apple 27. A voltage from a potentiostat 20 is applied across the counter electrode CE and an ohmic electrode OE in such a way that a depletion layer is created in a semiconductor substrate 10 (an optical scanning and sensing plate SP), and a prescribed bias voltage is applied to the substrate 10. When probing light L at a constant cycle (e.g. 10kHz) is made to irradiate continuously the sensing part 11 in this state, an AC photocurrent which reflects the pH of a dissolved substance or the cut face 27a coming into contact with the sensing face 14 is generated. The value of the photocurrent is measured, and a two-dimensional image expressing the pH concentration distribution of the apple 27 is displayed on a display 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dissolved substance concentration distribution measuring method capable of outputting a concentration distribution of a dissolved substance in a liquid or a liquid soaked in a substance as a two-dimensional or three-dimensional image.

[0002]

2. Description of the Related Art Conventionally, a liquid measuring sensor such as a pH electrode, an ion-selective ion electrode or a biosensor has been used to measure a dissolved substance in a liquid. The measurement of the dissolved substance performed by such a sensor is premised on the measurement in a state where the dissolved substance is sufficiently stirred and the distribution of the dissolved substance is uniform. Then, in order to measure the state in which the dissolved substance is unevenly present in the measurement solution or changes with time in a certain part and capture it as a two-dimensional or three-dimensional image, the sensor is arrayed or the sensor is used. It needs to scan itself.

[0003]

However, arraying the sensors requires miniaturization of the sensors, and a complicated device having as many input channels as the number of sensors and capable of processing the obtained signals. Need. Further, when the sensor itself is scanned, “measurement” and “movement of the sensor” are repeated, but most of the concentration distribution of the dissolved substance in the liquid changes rapidly with time, and “measurement” and “sensor The repetition of "movement" does not follow the rate of change.
In any case, it is difficult to devise the existing sensor alone, and a technological breakthrough is required.

Further, the measurement of a dissolved substance soaked in a substance is performed by adding distilled water or the like to the measuring object or grinding the measuring object to obtain a test liquid having a uniform concentration distribution, and measuring the whole test liquid. It is common to obtain information on dissolved substances contained in. Therefore, in this case as well, the distribution of the dissolved substance infiltrated into the substance cannot be known. A sensor that can be directly inserted into the measurement target has been proposed and put into practical use, but in this case as well, the dissolved substance is only information at one point in the measurement target, and the distribution of the dissolved substance in the target is measured. In order to do so, the "insertion" and "measurement" must be repeated, which involves the same problem as the above-described method of scanning the electrodes.

As described above, it is currently difficult to measure the concentration distribution of a dissolved substance in real time. Therefore, an electromagnetic wave image (visual shape grasp, photograph, CCD image, infrared light image, ultraviolet light image, X It is difficult to obtain the correlation in real time with the image obtained by all electromagnetic waves such as line image) and the chemical information of the dissolved substance.

As described above, it is currently difficult to measure the concentration distribution of the dissolved substance in real time. Therefore, it is the current situation to monitor the distribution state of the dissolved substance at a plurality of objects and at a plurality of points at one place. Is difficult.

The present invention has been made in consideration of the above-mentioned matters, and changes in the horizontal or vertical two-dimensional or three-dimensional concentration distribution of a dissolved substance in a liquid or a solution impregnated in the substance. Being able to output as an image in real time, comparing both the obtained concentration distribution image and the electromagnetic wave image of the portion where the concentration distribution image was obtained, and comparing it with the physical shape or part of the measurement target. , To be able to obtain a correlation with the distribution of dissolved substances contained therein or the chemical state indicated by the distribution of dissolved substances,
By performing these measurements at multiple measurement targets and multiple points on the earth and transferring the data to one location, it is possible to monitor the distribution of dissolved substances at multiple measurement targets and multiple locations in real time at one location. The object of the present invention is to provide a method for measuring the concentration distribution of dissolved substances.

[0008]

In order to achieve the above object, one method of measuring the concentration distribution of a dissolved substance of the present invention is:
While forming the sensing part on one surface of the semiconductor substrate, using a sensing plate configured to irradiate the semiconductor substrate with the light for the probe, the dissolved substance in the liquid or the liquid soaked in the substance It is characterized in that a two-dimensional or three-dimensional density distribution in the horizontal direction or the vertical direction or its change is measured, and this is subjected to image processing and displayed as a density distribution image on a display.

According to another method of measuring the concentration distribution of a dissolved substance of the present invention, a sensing portion is formed on one surface of a semiconductor substrate, and the semiconductor substrate is irradiated with probe light. The plate is used to measure the two-dimensional concentration distribution of the dissolved substance in the liquid or the liquid infiltrated into the substance and its change, and the signal obtained by this measurement is image processed to obtain the concentration distribution image. It is characterized in that an electromagnetic wave image of the portion where the density distribution image is obtained is obtained and both of the images are selectively or simultaneously displayed on the display.

Further, according to still another method of measuring the concentration distribution of a dissolved substance of the present invention, the sensing portion is formed on one surface of the semiconductor substrate, and the semiconductor substrate is irradiated with light for a probe. Using a sensing plate, measure the two-dimensional concentration distribution of a dissolved substance in a liquid or a liquid soaked in a substance and its changes at multiple measurement targets and multiple points, and collect the data obtained at that time in one place. It is characterized in that it is possible to monitor the distribution of a plurality of measurement targets and a plurality of dissolved substances by transferring the data to the.

[0011]

In the measurement of the above-mentioned dissolved substance, the two-dimensional distribution of the dissolved substance can be measured, and LAPS (Light-Addressa) can be measured.
ble Potentiometric Senso
r) An electrochemical image measuring device including a sensor is used. Such a device is disclosed, for example, in Jpn. J. Appl. Ph
ys. Vol. 33 (1994) pp L394-L3
As described in 97, the measurement can be performed by scanning the back surface side of the sensing portion with light and extracting the photocurrent induced in the semiconductor by this scanning.

The concentration distribution of the dissolved substance is measured by inserting or contacting the sensing plate of the above apparatus with the substance to be measured directly. The obtained data is output as a two-dimensional or three-dimensional density distribution image by computer processing. Not only the concentration distribution at a certain time,
The state of the change can be tracked in real time. The image obtained in real time can be easily compared with the electromagnetic wave image obtained by visual inspection, CCD camera or the like.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an outline of an apparatus for carrying out the method for measuring the concentration distribution of a dissolved substance according to the present invention. In this figure, 1 to 5 are a plurality of sensing plates for detecting the concentration of the dissolved substance in a sample. So, for example, sugar,
It detects pH, citric acid, pesticide components, etc., respectively. 6 is a CCD camera for visually detecting the physical shape of the sample, 7 is a sensing plate control device for scanning and controlling these sensing plates, 8 is an image processing device such as a computer, and 9 is an image output device. is there.

The sensing plates 1 to 5 for detecting the concentration of the dissolved substance will be described with reference to FIGS. 2 and 3, taking a sensing plate for pH measurement as an example. That is, in FIG. 2, 10 is Si
In this semiconductor substrate, the sensing portion 11 is formed on one surface of the Si substrate 10, and the probe light L is applied to the back surface of the sensing portion 11 on the other surface in the X and Y directions (see FIG. 3).
The light irradiation section 12 for sequentially irradiating the light is formed.

The sensing portion 11 is formed by sequentially forming a SiO ₂ layer 13 and a Si ₃ N ₄ layer 14 on the upper surface of the semiconductor substrate 10 by a method such as thermal oxidation or CVD. CE and RE are counter electrodes and reference electrodes provided above the sensing unit 11, and are a potentiostat 20 described later.
It is connected to the. OC is an ohmic electrode for current extraction provided on the semiconductor substrate 10, and is connected to the potentiostat 20.

Further, as shown in FIG. 3, the light irradiating section 12 holds a luminous body substrate 16 on which a plurality of LEDs 15 are formed at equal intervals, for example, in the X and Y directions, and the luminous body substrate 16. Address decoders 17X, 1 for controlling the LEDs 15 to sequentially light up.
7Y and a printed circuit board 18 as a scanning control unit.

The sensing unit 11 and the light irradiation unit 12 are
Although formed separately, the light emitting substrate 16 is directly bonded to the surface of the Si substrate 10 opposite to the sensing portion 11 by using an appropriate adhesive or a technique such as anodic bonding or direct bonding. Accordingly, the optical scanning type sensing plate S having a composite structure (hybrid structure) is provided.
P is formed.

In FIG. 2, 19 is a control device for the optical scanning type sensing plate SP, which is a potentiostat 20 for applying an appropriate bias voltage to the semiconductor substrate 10 and an ohmic electrode formed on the semiconductor substrate 10. A current-voltage converter 21 for converting the current taken out from the OC into a voltage signal, a lock-in amplifier 22 to which the signal from the current-voltage converter 21 is input, a signal exchanged with the lock-in amplifier 22, and an optical signal. It is composed of an interface board 23 which outputs a control signal to the irradiation unit 12. In addition, 24 is a microcomputer (CPU) as a control / arithmetic unit, and 25 and 26 are a keyboard for input and a display as a display output unit, respectively.

Optical scanning type sensing plate S having the above structure
The case of measuring the pH of an apple using P will be described. As shown in FIGS. The sensing surface 11 (in this case, the Si ₃ N ₄ layer 14) is directly contacted, and the counter electrode CE and the reference electrode RE are inserted into the apple 27.

Then, the voltage from the potentiostat 20 is applied to the counter electrode C so that a depletion layer is generated in the semiconductor substrate 10.
A predetermined bias voltage is applied to the semiconductor substrate 10 by applying the voltage between E and the ohmic electrode OC. In this state, the probe light L for the sensing unit 11 is intermittently applied to the semiconductor substrate 10 at a constant cycle (for example, 10 kHz) to generate an AC photocurrent in the semiconductor substrate 10. This photocurrent is a value that reflects the pH of the cut surface 27a of the apple 27 that is in contact with the sensing surface 14 at the point facing the irradiation point of the semiconductor substrate 10, and by measuring the value, It is possible to know the pH value of.

Further, the probe light L is scanned in the X and Y directions by sequentially causing the LED 15 to emit light, and the position signal (X, Y) in the cross section 27a of the apple 27 and the AC photocurrent value observed at that position are detected. Thereby, as shown in FIG. 4C, a two-dimensional image 28 representing the pH concentration is displayed on the display 26.

The optical scanning type sensing plate SP
Was a hybrid structure, but it can also be configured as an integrated structure (monolithic structure). Also, the reference electrode R
Although E may be omitted, when the comparison electrode RE is provided, the bias voltage can be more stably applied to the semiconductor substrate 10.

Further, in the above-described embodiment, the probe light L is emitted from the back surface side of the semiconductor substrate 10, but instead of this, it may be emitted from the sensing portion 11 side.

Optical scanning type sensing plate SP described above
Used to measure the pH, but the Si ₃ N ₄ layer 14
The distribution of various components can be measured by appropriately selecting a substance that modifies, for example, by modifying the Si ₃ N ₄ layer 14 with various lipids, components related to taste such as sweetness and sourness can be measured. You can know. The distribution of harmful substances such as pesticides can also be measured by modifying the Si ₃ N ₄ layer 14 with an appropriate responsive substance.

Returning to FIG. 1 again, the sensing plates 1 to 5 shown in FIG. 1 basically have the structure shown in FIGS. 2 and 3, and only the Si ₃ N ₄ layer 14 is provided. The only difference is the responder that modifies. By doing so, in this example, a two-dimensional distribution of five different substances (components) can be obtained. Also CCD
The camera 6, for example, shows the sectional shape of the apple 27 as shown in FIG.
0 shows an electromagnetic wave image of the apple 27.

In the device constructed as described above,
By sequentially contacting and scanning the cut surface 27a of the apple 27 cut in half with the sensing surfaces 14 of the sensing plates 1 to 5,
Thus, a two-dimensional distribution of a plurality of substances (components) on the cut surface 27a of the apple 27 is obtained, and the data is stored in the memory of the image processing device 8. Then, during the contact scanning, the CCD camera 6 captures an image of the cutting surface 27a to obtain image data of the cutting surface 27a, which is also stored in the memory of the image processing device 8.

By appropriately operating the operation unit (not shown) of the image processing apparatus 8, the display form on the image output apparatus 9 can be appropriately changed. As shown by reference numerals 91 to 95 in FIG. In addition, the distribution image of the substance (component) obtained by the sensing plates 1 to 5 and the electromagnetic wave image 96 of the portion where the concentration distribution image is obtained can be simultaneously obtained. In other words, by comparing the electromagnetic wave image of the cross section monitored and the distribution image of the dissolved substance, it is determined whether the apple 27 is sufficiently mature to the inside, the distribution of the sourness of the apple 27, and the harmful substances such as pesticides. It is possible to easily confirm the distribution and the like by visual observation. Further, in the figure, as indicated by reference numeral 97, a specific screen can be greatly enlarged to display the distribution state in more detail, and the display switching can be performed only by key input on the operation unit. .

The optical scanning type sensing plate SP can be used not only for measuring the distribution of the substance (component) in the cross section of the apple 27 as described above, but also for the following distribution measurement. For example, when measuring the distribution of pH in soil, as shown in FIG. 5 (A), a hole is dug into the soil to allow insertion of the optical scanning sensing plate SP,
In this hole, the optical scanning type sensing plate S shown in FIG.
Fill P with counter electrode CE and reference electrode RE. Whether to examine the vertical distribution or the horizontal distribution of pH in the soil is determined by the installation direction of the optical scanning type sensing plate SP, and in the example shown in FIG. 5A, the vertical distribution of pH can be examined. When carrying out this measurement, the distribution of pH can be investigated by allowing the soil to have appropriate water content. Then, not only the distribution at a certain time but also the change with time of the distribution can be examined.

The optical scanning type sensing plate SP
Is not only the distribution of pH in the soil, but also Si ₃ N
By modifying the _4th layer 14 with a substance that selectively responds to a specific substance, a distribution image of dissolved substances other than pH can be obtained, which can be used as an index for more diverse soil diagnosis and evaluation. .

Further, the distribution of carbon dioxide in river water or seawater can be continuously monitored by using the optical scanning type sensing plate SP. When performing such measurements, the surface of the Si ₃ N ₄ layer 14 need not be modified and only the pH change caused by the change in dissolved carbon dioxide should be tracked. That is, as shown in FIG. 5 (B), the optical scanning sensing plate SP together with the counter electrode CE is installed in the water to be measured, and the output is transferred to the processing unit on land by a cable to dissolve dissolved carbon dioxide in the water. The distribution of can be tracked in real time. Also in this case, whether to examine the vertical distribution or the horizontal distribution is determined by the installation direction of the sensor, and further, by modifying the Si ₃ N ₄ layer 14 with a substance that selectively responds to a specific substance,
A distribution image of dissolved substances other than dissolved carbon dioxide can be obtained, and can be used as an index for more diverse diagnosis and evaluation in water.

In FIG. 6, the above-mentioned measurement is carried out at a plurality of places regardless of soil or water, and a signal based on the measurement is transmitted to the monitoring center 30 by a transmission means 31 such as a cable or a telephone line for data transmission. Transmitted by
An example is shown in which the distribution images of the dissolved substances at each point can be collectively monitored at one location by outputting and displaying them on a plurality of display output devices 32. By doing so, by knowing the distribution of various dissolved substances at various points in multiple directions, it is possible to obtain an index for conservation of the natural environment and an index for new resource development.

[0032]

As described above, according to the first aspect of the present invention, a dissolved substance in a liquid such as a solution or in a liquid impregnated in a substance is two-dimensionally or three-dimensionally in the horizontal or vertical direction. The density distribution and changes in this density distribution can be obtained as an image in real time.

According to the invention described in claim 2,
In addition to the effect of the invention described in claim 1, it is possible to clearly understand the correlation between the physical shape or part of the measurement target and the distribution of the dissolved substance contained therein or the chemical change indicated by the distribution of the dissolved substance. be able to.

Further, according to the invention described in claim 3, in addition to the effect of the invention described in claim 1, it is possible to monitor the distribution of a plurality of measurement targets and a plurality of dissolved substances in one place in real time. it can.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of an apparatus for carrying out a dissolved substance concentration distribution measuring method of the present invention.

FIG. 2 is a diagram schematically showing a configuration example of an optical scanning type sensing plate used in the apparatus.

FIG. 3 is a diagram schematically showing a configuration example of a light irradiation unit of the light scanning type sensing plate.

FIG. 4 is an operation explanatory view of the dissolved substance concentration distribution measuring method of the present invention.

FIG. 5 is a diagram showing a measurement method using the optical scanning type sensing plate, (A) shows measurement of pH in soil,
(B) is a figure which shows roughly the measurement of the dissolved carbon dioxide in water, respectively.

FIG. 6 is a diagram showing an embodiment of the measuring method of the present invention.

[Explanation of symbols]

1 to 5 ... Sensing plate, 9, 26 ... Display, 10 ... Semiconductor substrate, 11 ... Sensing unit, 12 ... Light irradiation unit, L ... Probe light, SP ... Sensing plate.

Claims (3)

[Claims] 1. A liquid impregnated in a liquid or a substance using a sensing plate configured to form a sensing portion on one surface of a semiconductor substrate and irradiate the semiconductor substrate with light for a probe. Concentration distribution of the dissolved substance characterized by measuring the concentration distribution and its change in the horizontal or vertical two-dimensional or three-dimensional direction of the dissolved substance in the inside, and processing it as a concentration distribution image on the display Measuring method. 2. A liquid impregnated in a liquid or substance using a sensing plate configured to form a sensing portion on one surface of a semiconductor substrate and irradiate the semiconductor substrate with light for a probe. The two-dimensional concentration distribution of the dissolved substance in the inside and its change are measured, and the signal obtained by this measurement is subjected to image processing to obtain a concentration distribution image, while the electromagnetic wave image of the portion where this concentration distribution image is obtained is obtained. A method for measuring the concentration distribution of a dissolved substance, which comprises displaying both images selectively or simultaneously on a display. 3. A liquid impregnated in a liquid or substance using a sensing plate configured to form a sensing portion on one surface of a semiconductor substrate and irradiate the semiconductor substrate with light for a probe. By measuring the two-dimensional concentration distribution of dissolved substances and its changes at multiple measurement targets and multiple points, and transferring the data obtained at that time to one location, multiple measurement targets and multiple dissolved substances A method for measuring the concentration distribution of a dissolved substance, characterized in that the distribution of the substance can be monitored.