JPH0225714A - Interface measuring instrument - Google Patents

Abstract

PURPOSE:To detect an interface of an inspection body without touching the inspection body by placing a light emitting element, a light receiving element and a reflecting part in the horizontal direction and in parallel by inserting and holding a bottomed cylindrical container being in an erect state, and detecting the variation of a reflected light by the light receiving element. CONSTITUTION:In a state that a holding body 11 has is to the upper end part of a container 6, a light emitting element 15 is lighted and the inside of the container 6 is irradiated by a light beam from the tip of an optical fiber 9, the holding body 11 is allowed to descend along the longitudinal direction of the container 6 by a driving circuit 13 and a pulse motor 12. When the holding body 11 moves in an area of air, a small light beam which is emitted from the light emitting element 15 and reached a light receiving area on a reflecting member 20 reaches a light receiving element 16, and a signal of a low level is detected. Also, when said holding body passes through an area of a blood serum 8a, a large quantity of light beams are made incident on the light receiving element 16 by a variation of a refractive index, and a signal of a high level is detected. Moreover, when said holding body passes through an area of a blood clot 8b, the light beam is absorbed by the blood clot 8b, therefore, no light beam is made incident on the light receiving element 15. The variation of these detecting signals is detected by a detecting circuit 17, and led into an arithmetic circuit 18.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an interface measuring device that is effective for use in an automatic dispensing device for dispensing a specimen.

[Prior art] In an automatic pipetting device, when aspirating a sample with a pipette, the tip of the pipette must be inserted a certain length into the liquid surface of the sample to prevent the sample from adhering to the pipette as much as possible. Must be. For this purpose, it is necessary to measure the liquid level of the sample, that is, the interface between the air and the sample. Further, when aspirating, for example, centrifuged blood as a specimen, it is necessary to measure the amount of serum in advance. For this purpose, it is necessary to also measure the interface between the separated serum and blood clot.

A device for measuring such an interface has two optical fibers arranged side by side at the tip of a pipette, and as the pipette is lowered, one optical fiber emits light toward the liquid surface, and the other optical fiber emits light toward the liquid surface. By detecting the light reflected from the liquid surface, the pipette is stopped when the detection signal reaches a certain set value (in other words, when the pipette reaches the liquid surface). A commonly used method is to attach the ends of pipes connected to a compressor side by side and detect the pressure change inside the vibrator as the pipette approaches the liquid level to detect the liquid level.

[Problems to be Solved by the Invention] In such a conventional method, two sets of optical fibers or vibrators must be attached to the tip of the pipette, resulting in a complicated structure. Furthermore, since an optical fiber or a vibrator is inserted into the specimen along with the pipette, it is impossible to avoid the specimen from adhering to the optical fiber or the vibrator. Therefore, since the optical fiber and the vibrator must be cleaned in addition to the pipette, the cleaning becomes complicated, and the cleaning is likely to be insufficient, and there is a risk that the specimen attached to the optical fiber or the vibrator may contaminate other specimens. Furthermore, in the latter method,
The interface between separated serum and blood clot cannot be detected.

SUMMARY OF THE INVENTION The present invention has been made in view of these points, and an object of the present invention is to provide an interface measuring device that has a simple configuration and can detect an interface without touching the specimen. be.

[Means for Solving the Problems] In order to achieve the above object, the boundary surface measuring device of the present invention includes a transparent bottomed cylindrical container arranged in an upright state to contain a liquid, and a transparent bottomed cylindrical container arranged in an upright state to contain a liquid. a light emitting element disposed on the outer periphery of the container to allow light to enter the container; a reflecting member disposed opposite to the light emitting element with the container sandwiched therebetween; a light emitting element that reflects light from the reflecting member and passes through the container A light-receiving element arranged in parallel with the light-emitting element for detection, and a moving mechanism for holding the light-emitting element and the light-receiving element together and moving them along the longitudinal direction of the container, This method is characterized in that the boundary surface is detected based on the change in the signal.

[Effect] Next, the principle of the present invention will be explained in detail based on FIG.

In the present invention, a transparent bottomed cylindrical container 1 placed upright is sandwiched between a light emitting element 2, a light receiving element 3 and a light receiving element 3 placed horizontally and parallel to each other and separated from each other by a certain distance. The member 4 is arranged.

In this arrangement, when the light from the light emitting element 2 is made to enter the container 1, the spread of the light is small when the inside of the container is air, and as shown by the solid line in the figure, the light emitted from the light emitting element 2 on the surface of the reflecting member 4 is Since the irradiation area A and the light-receiving area B by the light-receiving element 3 do not overlap, reflected light does not enter the light-receiving element. On the other hand, when light is irradiated to the area where the specimen is present, the spread of the light becomes larger than that of air, and as shown by the dotted line in the figure, the irradiated area and the light-receiving area on the surface of the reflective member 4 are at the same sign. Since they partially overlap as shown by C, reflected light enters the light receiving element 3. Therefore, if the two light-emitting elements 2 and the light-receiving element 3 are held together and moved from a certain reference position along the longitudinal direction of the container, and a change in the detection signal from the light-receiving element is detected, air It is possible to detect the interface with the specimen. As a result, by determining the moving distance of each element from the reference position where each element 2, 3 starts moving until the detection signal is detected,
The liquid level of the sample contained in the container can be measured.

On the other hand, the interface between two separated components can also be easily measured. If one of the serum and blood clots is obtained by centrifuging blood, and one transmits light well while the other does not, a detection signal is generated in the serum part, and a detection signal is generated in the blood clot part. Since the detection signal is no longer generated because the detection signal is blocked, the presence of the interface between the two and four liquids can still be detected.

Hereinafter, embodiments of the present invention will be explained in detail based on the drawings.

[Example] FIG. 2 is a longitudinal sectional view showing an example of the interface measuring device according to the present invention, FIG. 3 is a plan view of FIG. 2, and FIG. 4 is a diagram for explaining the operation.

In FIGS. 2 and 3, reference numeral 5 denotes a specimen holder in which a cylindrical container 6 with a bottom is held upright.

Further, this holder has corrosion resistance, and its surface is formed in a highly reflective color, for example, white.Furthermore, a slit 7 is formed along the longitudinal direction of the container 6 in the center of the side surface of the holder. is formed. Two types of separated specimens, for example, serum 8a and blood clot 8b, are stored in the container 6.

Reference numeral 9.10 denotes an optical fiber, one end of which is held in a horizontal position by a holder 11, and each tip thereof is arranged to face the slot 7 of the holder 5. Further, each of the optical fibers is attached to the holder horizontally at equal intervals around the axis of the container. This length of separation is set so that it is slightly inside the inner diameter of the container. The holder 11 is attached to a vertical movement mechanism (not shown) such as a combination of a rack and a pinion, and is moved vertically along the longitudinal direction of the container 6 as shown by arrow F in FIG. 2 is a pulse motor that drives the vertical movement mechanism of this holding body 11, and 13 is a driving circuit thereof.

On the other hand, the other ends of the optical fibers 9 and 10 are connected to the boundary surface detection section 14 in a bundled state. This boundary surface detection section includes a light emitting element 15 such as a light emitting diode for supplying light to the optical fiber 9, a light receiving element 6 such as a photodiode for detecting light transmitted through the optical fiber 10, and a detection circuit 8. It consists of 17. A detection signal from this boundary surface detection section 14 is sent to an arithmetic circuit 18. 19 is a counter for counting the pulses sent from the drive circuit 13, and the output signal from the counter 20 is sent to the arithmetic circuit 18. Incidentally, in the outer wall portion of the container 6 that sandwiches the specimen (blood) and faces the optical fibers 9 and 10, a reflective member, for example, a white paper 20, is pasted to the portion that is not in contact with the holder 5.

The operation in this configuration will be explained in detail below.

Now, the holder 11 is set on the upper end of the container 6 as shown in FIG.
When the drive circuit 13 is activated in a state in which light is irradiated into the container 6 from the tip, a pulse signal is supplied to the pulse motor 12 and rotates, so that the holder 11 is moved from the position shown in FIG. 2 to the longitudinal direction of the container 6. Descend along the direction. When the optical fibers 9 and 10 pass through the liquid level of the serum 8a and the interface between the serum 8a and the blood clot 8b, the first
Since the amount of signal detected by the detection circuit 17 changes according to the principle explained in the figure, the boundary surface detection section 14 generates signals Pi and P2 according to the position of each boundary surface as shown in FIG. It is introduced into the arithmetic circuit 18. On the other hand, since the pulse signal from the drive circuit 13 is also sent to the counter 19, the number of pulses from the start of the holding body 11 is counted, and the count value is sequentially sent to the calculation circuit 18. Therefore,
In the arithmetic circuit, a signal P1 corresponding to the liquid level of serum 8a
is introduced, C1, which is the pulse count value at that time, is stored in the register 21a.

Furthermore, when the signal P2 corresponding to the interface between the serum 8a and 8b is introduced, the count value C2 at that time is stored in the register 21b.

Here, 6 g, which is the moving distance of the moving body 11 per one pulse, and S, which is the cross-sectional area of the inner diameter of the container 6, are stored in advance in the arithmetic circuit 18. When detecting the liquid level position of the serum, it is sufficient to find the length Ll from the start position (reference position) of the holder 11 to the position where the signal P1 is generated, and the length Ll is found by LL-CIXΔg. It will be done.

On the other hand, when detecting the volume V of the serum 8a, the length L2 of the serum may be determined, and the length L2 may be multiplied by the cross-sectional area S of the container. Since the length L2 of serum is L2-(C2-CI) x 6g, the volume V of serum is V-(C2-CI) x ΔN
Find it by xs. : Can be done.

By doing as described above, there is no need to attach the boundary surface detection means to the pipette as in the conventional case, so that it is possible to prevent the boundary surface detection means from coming into contact with the sample.

Therefore, the sample adhering to the interface detection means does not contaminate other samples, and there is no need to clean the interface detection means, resulting in a simplified configuration.

It should be noted that the above description is one embodiment of the present invention, and many modifications may be made in implementing the present invention. For example, optical fiber 9.
When attaching 10 to the holder 11, it is necessary to separate 9 and 10, but since this distance has an optimum value depending on the inner diameter of the container used, it is necessary to select it according to the thickness of the container.

Furthermore, by attaching two or more pairs of optical fibers to the holder, it is possible to arbitrarily detect the interface between specimens housed in two or more containers with different diameters. At this time,
Needless to say, the optical fiber should be changed to one suitable for the size of the container used.

Furthermore, although an optical fiber was used in the above embodiment, the light emitting element and the light receiving element may be directly attached to the holder without using the optical fiber.

[Effects] As detailed above, according to the present invention, the interface of the specimen can be detected without contacting the specimen.
It is possible to prevent the specimen from being contaminated through the interface detection means, and it is not necessary to clean the interface detection means, so the configuration can be simplified.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining the present invention in detail, Fig. 2 is a vertical sectional view showing an example of the interface measuring device according to the invention, Fig. 3 is a plan view of Fig. 2, and Fig. 4 is an operation. FIG. 1.6: Container 2,15: Light emitting element 3.16 Two light receiving elements 4.20: Reflective member 5: Holder
7: Slit 8a: Serum 8b: Blood clot 9.10: Optical fiber 11: Holder 12: Pulse motor 13: Drive circuit 14: Interface detection unit 17: Detection circuit
18: Arithmetic circuit 19: Counter 21a, 21b = register

Claims (1)

[Claims] A transparent cylindrical container with a bottom placed upright to contain a liquid, a light emitting element placed on the outer periphery of the container to allow light to enter the container from a horizontal direction, and a light emitting element sandwiching the container. A reflecting member disposed opposite to the light emitting element; a light receiving element disposed in parallel with the light emitting element for detecting light reflected from the reflecting member and passing through the container; and the light emitting element and the light receiving element are integrated. A boundary surface measuring device comprising: a moving mechanism for holding and moving the container along the longitudinal direction; and detecting a boundary surface based on a change in a signal obtained from the light receiving element.