JP2005181105A - Dispensing method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a detecting method of highly precise suction fluid volume, which suppresses unnecessary radiation and does not receive an influence of disturbance. <P>SOLUTION: The dispensing device comprises: a nozzle 16 which attracts the fluid in a sample container 21; a fluid volume detection means for detecting fluid volume in the nozzle by the fluid level detection; a pump actuator 11 which performs suction and discharge of a sample; a conveying means of a nozzle or a sample container; and a dispensing control unit 10 for controlling the fluid volume detection means, the pump actuator 11 and the conveying means. The fluid volume detection means includes: a distributed constant line consisting of a pair of electrodes provided in the nozzle; a reflected wave detecting circuit connected to another side of the pair of electrodes; a fluid volume computing circuit for obtaining the fluid volume by detecting the delay time and amplitude value of a radiation signal generated by a radiation wave and a reflection signal reflected by a reflected wave; and a comparison circuit which outputs a signal to the pump actuator at the time of fluid contacting to a sample interface. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a dispensing method and apparatus having a mechanism for sucking a predetermined amount of liquid using an electrical signal and discharging it to a target container.

A conventional dispensing method and apparatus includes a nozzle for sucking a sample, an ultrasonic generator for radiating from the base end side of the nozzle to the nozzle internal space, and an ultrasonic wave receiving the reflected wave of the ultrasonic wave. A ultrasonic sensor and means for detecting a liquid level in the nozzle based on a received signal from the ultrasonic sensor, and the reflected wave reflected by the liquid level in the nozzle is received by the ultrasonic sensor. The liquid level of the sample sucked in the nozzle is detected by recognizing the liquid level as an echo and recognizing the time from the time of transmission to the occurrence of the liquid level echo as the level of the liquid level of the sample in the nozzle. . (For example, refer to Patent Document 1).
FIG. 7 is a block diagram showing a conventional dispensing apparatus. In FIG. 7, 10 is a dispensing control unit, 11 is a pump drive mechanism, 16 is a nozzle, 20 is a sample, 21 is a sample container, 50 is an ultrasonic sensor, 51 is a nozzle tip, 52 is a nozzle head, and 53 is an ultrasonic wave. It is. By sucking the inside of the nozzle 16 by the pump drive mechanism 11 connected to the nozzle 16, the sample 20 is sucked into the nozzle chip 51, and an ultrasonic wave 53 is generated inside the nozzle 16 from the nozzle head 52. The echo reflected from the sample 20 is received by the ultrasonic sensor 50, and the liquid level is detected by detecting the transmission and reception of the ultrasonic wave 53 as a time difference by the dispensing control unit 10, and a predetermined sample is detected based on the detected value. A pump drive control signal 60 is transmitted to the pump drive mechanism 11 so as to suck 20, and the sample 20 is sucked.
As described above, the conventional dispensing method and apparatus detect the amount of liquid sucked into the nozzle by detecting the liquid level by transmitting and receiving ultrasonic waves.
Japanese Patent Laid-Open No. 9-264772 (FIG. 1)

The conventional dispensing method and apparatus have a problem that the detection sensitivity of the radiated wave and the reflected wave by the ultrasonic sensor is low, and an error occurs according to the length of the nozzle. In addition, ultrasonic waves generate unnecessary radiation and are difficult to detect due to disturbances, resulting in a large error in the amount of suction liquid.
Accordingly, the present invention has been made in view of such problems, and is a dispenser that can suppress unnecessary radiation in electrical liquid level detection and suppress the influence of disturbance to obtain a highly accurate suction liquid amount. It is an object to provide a method and apparatus.

In order to solve the above problems, the present invention is configured as follows.
According to the first aspect of the present invention, the liquid in the sample container is sucked into the nozzle, the liquid level in the nozzle is detected, a predetermined amount of sample liquid is sucked, and then discharged and distributed to another container. In the dispensing method, the amount of the sample liquid is provided with an electrode pair serving as a distributed constant line in the nozzle, a radiated wave is applied between the electrodes, and a delay time between the radiated signal due to the radiated wave and the reflected signal of the reflected wave And detecting the amplitude value of the reflected signal.
According to a second aspect of the present invention, the reflected signal is generated by a change in an impedance value generated when the nozzle contacts the sample interface and when the sample is sucked into the nozzle.
According to a third aspect of the present invention, there is provided a nozzle for sucking a liquid in a sample container, a liquid amount detecting means for detecting a liquid amount by detecting a liquid level in the nozzle, and a pump driving unit for sucking and discharging the sample. And a dispensing unit comprising: a conveying unit that moves the nozzle or the sample container; and a controller that controls the liquid amount detecting unit, the pump driving unit, and the conveying unit. A distributed constant line comprising an electrode pair provided in the nozzle; a radiant wave generating circuit for applying a radiant wave connected to one of the electrode pairs; a reflected wave detecting circuit connected to the other of the electrode pair; and the radiated wave A liquid amount calculation circuit for obtaining the liquid amount by detecting the amplitude value and delay time of the radiation signal and the reflected signal of the reflected wave, and a comparison circuit for outputting a signal to the pump drive unit when the liquid contacts the sample interface It consists of .
According to a fourth aspect of the present invention, the nozzle includes a cylindrical inner conductor, a spacer made of an insulating material provided on an outer peripheral portion of the inner conductor, and an outer peripheral portion of the spacer provided coaxially with the inner conductor. It consists of a cylindrical outer conductor.
According to a fifth aspect of the present invention, the spacer has a plurality of gaps arranged radially about the axis of the inner conductor.
According to a sixth aspect of the present invention, the spacer can obtain a constant characteristic impedance depending on the relative dielectric constant and the number thereof.
According to a seventh aspect of the present invention, the spacers are disposed in the upper and central portions of the nozzle in the vertical direction.
According to an eighth aspect of the present invention, an anticorrosion coating film is applied to the surface of an electrode pair constituting the nozzle.
According to a ninth aspect of the present invention, the radiation wave generation circuit generates a rise time and a pulse width of the radiation wave with a pulse of sub μs or less.

According to the first and third aspects of the present invention, since the nozzle including the electrode pair structure is a distributed constant line, the signal attenuation of the reflected wave with respect to the radiated wave can be minimized and the liquid level of the sample Can be detected with high sensitivity. Further, when the nozzle is in contact with the sample, the reflection coefficient at the tip of the nozzle largely fluctuates, so that the liquid contact can be easily detected.
According to the second aspect of the present invention, it is possible to easily detect the difference between the reflected signal of the liquid contact with the sample of the nozzle and the sample suction, and to move up and down to move the nozzle tip to the liquid level of the sample container until the nozzle comes into contact with the liquid. Since a signal is sent only to the apparatus and only a suction or discharge signal is sent to the pump drive device after the liquid contact, the load on the control unit can be reduced and a dispensing operation can be performed at high speed.
According to the invention described in claim 4, since the nozzle has a coaxial cylindrical shape, it is possible to suppress the influence on the electromagnetic wave from the outside, and it is possible to suppress the external leakage of unnecessary radiation due to the radiated wave and the reflected wave. In addition, the structure is simple and the maintainability can be improved.
According to the fifth aspect of the present invention, since the gaps for conducting the gas and the liquid are formed radially, the impedance characteristics of the spacer can be stabilized, and the measurement by the high-frequency component of the radiated wave can be performed. be able to.
According to the sixth aspect of the invention, since a constant characteristic impedance can be obtained by the spacer, a stable reflected wave can be detected without being limited by the nozzle length.
According to the seventh aspect of the present invention, since the spacer is disposed so as not to come into contact with the liquid, the influence of the sample on the impurities can be reduced, and the nozzle can be reliably cleaned. Moreover, since the change of the reflection coefficient at the time of liquid contact can be directly detected, the liquid contact can be reliably detected.
According to the eighth aspect of the invention, since the anticorrosion coating film is applied to the surface of the nozzle electrode pair, the corrosion resistance can be improved. In addition, even when a sample having a relatively high conductivity is used, it is possible to suppress electrical failure including sparks.
According to the ninth aspect of the invention, since the rising time and the pulse width of the radiated wave are set to sub μs or less, the reflected wave can be detected more easily than the radiated wave having the generated wave tail length. Further, since the high-speed pulse is used as the radiation wave, interference with the reflected wave can be minimized.

  Hereinafter, specific examples of the method of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a dispensing apparatus showing a first embodiment of the present invention. In the figure, the same reference numerals are used for common parts, 10 is a dispensing control unit, 11 is a pump drive unit, 12 is a manifold, 13 is an internal conductor, 14 is an external conductor, 15 is a spacer, 16 is a nozzle, Reference numeral 17 denotes a lifting device. The nozzle 16 includes a coaxial cylindrical inner conductor 13 and an outer conductor 14 and a spacer 15 that keeps the distance constant.
The cross section of the spacer 15 is as shown in FIG. FIG. 2 is a cross-sectional view of the spacer taken along line AA ′ of FIG. In the figure, reference numeral 18 denotes an air gap, 19 denotes an internal conductor air gap, and a plurality of air gaps 18 are arranged radially around the internal conductor air gap 19. The gap 18 has a circular shape in FIG. 2A and a trapezoidal shape in FIG.
The dispensing control unit 10 has a circuit configuration shown in FIG. In the figure, 19 is an internal conductor gap, 30 is a radiation wave generation circuit, 31 is a reflected wave detection circuit, 32 is a comparison circuit, 33 is a time delay detection circuit, 34 is an arithmetic circuit, 35 is a liquid amount detection circuit, and 36 is It is a signal output circuit.
The portion where the present invention is different from Patent Document 1 is a portion in which the nozzle body is constituted by a distributed constant line, and the nozzle body serves as a detector for the sample liquid level.

Next, the operation of this embodiment will be described with reference to FIGS.
FIG. 4 is a time chart showing the liquid level and the liquid amount detection. In the figure, 40 is a radiation signal, 41 is a reflection signal, 42 is a liquid contact signal, 43 is a liquid amount adjustment signal, 44 is a delay time, and 45 is a peak value. The reflected signal 41 is divided into a reflected signal 41a before liquid contact and a reflected signal 41b after liquid contact. Further, 60 in FIG. 1 is a pump drive control signal, and 61 is an elevation control signal.
(1) A radiation wave shaped into a predetermined shape is inputted from the radiation wave generation circuit 30 to the internal conductor 13 constituting the nozzle 16.
(2) The radiated wave propagates through the nozzle 16 constituted by a distributed constant line, a reflected wave is formed according to the impedance of the tip of the nozzle 16, and is introduced into the reflected wave detection circuit 31.
(3) When the nozzle is not in contact with the sample 20, basically no reflected wave is detected. For this reason, since it is not necessary to calculate the time difference between the radiated wave and the reflected wave below the threshold value set in the comparison circuit 32, the signal output circuit 36 outputs the elevation control signal 61 only to the elevation mechanism 17 and the nozzle 16 Lower until the tip is wetted.
(4) When the reflection signal 41a (FIG. 4) is detected, the comparison circuit 32 outputs the liquid contact signal 42 to stop the operation of the lifting mechanism 17.
(5) At the same time, the liquid level in the nozzle 16 is calculated from the radiation signal 40a detected by the delay time detection circuit 33, the delay time 44 between the reflected signals 41b, and the peak value 45 of the reflected signal 41b.
(6) The suction of the sample 20 is started by outputting a pump drive control signal 60 to the pump drive mechanism 11 through the signal output circuit 36 with the liquid amount adjustment signal 43 correlated with the calculation result.
(7) When the predetermined liquid amount is reached, the pump drive mechanism 11 is stopped by the liquid amount adjustment signal 43 to end the predetermined liquid amount suction.

  Thus, since the nozzle including the electrode pair structure is a distributed constant line, the signal attenuation of the reflected wave with respect to the radiated wave can be minimized, and the liquid level of the sample 20 can be detected with high sensitivity. Can do. When the nozzle 16 comes into contact with the sample 20, the reflection coefficient at the tip of the nozzle 16 largely fluctuates, so that the liquid contact can be easily detected. A signal can be easily detected and a signal is sent only to the elevating mechanism 17 that moves the tip of the nozzle 16 to the liquid level of the sample container 21 until the nozzle 16 is in contact with the liquid. Therefore, the load on the dispensing control unit 10 can be reduced and the dispensing operation can be performed at high speed. Further, since the nozzle 16 has a coaxial cylindrical shape which is one of the distributed constant lines, it is possible to suppress the influence on the electromagnetic wave from the outside, and it is possible to suppress the external leakage of unnecessary radiation due to the radiated wave and the reflected wave.

  Further, since the nozzle 16 is disposed via the spacer 15 that keeps the distance between the inner conductor 13 and the outer conductor 14 constant, the inner conductor 13 can be reliably disposed on the central axis of the outer conductor 14, Since the nozzle 16 has a coaxial cylindrical shape, it is possible to suppress the influence on the electromagnetic wave from the outside, and it is possible to suppress the external leakage of unnecessary radiation due to the radiated wave and the reflected wave. Since the gaps 18 for conducting the gas and the liquid are formed in a radial shape, the impedance characteristics of the spacer 15 itself can be stabilized, the measurement by the high frequency component of the radiated wave can be made, and the structure is simple. Therefore, maintainability can be improved. In addition, since the spacer 15 obtains a constant characteristic impedance depending on the relative dielectric constant and the number thereof, a stable reflected wave can be detected without being limited by the length of the nozzle 16.

FIG. 5 is a block diagram of a dispensing apparatus showing a second embodiment of the present invention, and FIG. 6 is a time chart for detecting the liquid level and the liquid amount. A coating film 22 is applied to the surface of the electrode pair to prevent corrosion due to the sample. The spacers 15 are arranged at the upper part and the central part other than the tip of the nozzle 16 and the liquid contact part.
The radiation signal is a pulse having a rise time and a pulse width of sub μs or less.
The part where the present invention is different from Patent Document 1 is a part in which the nozzle body is constituted by a distributed constant line and the surface of the nozzle body is covered with a coating film.

Next, the operation of this embodiment will be described. In FIG. 6, 41c is a reflection signal before liquid contact, and 41d is a reflection signal after liquid contact.
Operations 1) to (3) are the same as in the first embodiment.
(4) When the reflection signal 41c is detected, the comparison circuit 32 outputs the liquid contact signal 42 to stop the operation of the lifting mechanism 17.
(5) At the same time, the liquid level in the nozzle 16 is calculated from the delay time 44 between the radiation signal 40b and the reflection signal 41d detected by the delay time detection circuit 33 and the peak value of the reflection signal 41d.
(6) to (7) are the same as in the first embodiment.

As described above, since the spacer 15 is disposed at a position other than the tip of the nozzle 16 and the liquid contact portion, the influence on the impurities of the sample 20 can be reduced, the cleaning of the nozzle 16 can be performed reliably, and the reflection at the time of liquid contact can be achieved. Since the change of the coefficient can be detected directly, the liquid contact can be detected reliably. Since the coating film 22 is provided on the surface of the electrode pair of the nozzle 16, the corrosion resistance can be improved, and even when the sample 20 having a relatively high conductivity is used, an electrical failure such as a spark is suppressed. be able to.
In addition, by making the rise time and the pulse width of the radiation signal 40 less than sub μs, the reflected signal 41 can be easily detected as compared with the radiation signal 40 having a long wave tail length such as a square wave. Since the pulse is used as the radiation signal 40, the interference with the reflected signal 41 can be minimized and the detection can be simplified.

  Since the present invention can use a nozzle constituted by a distributed constant line as a liquid level sensor, it can also be applied as a single sensor, and can also be applied to other fields in which fine liquid is sucked and discharged.

It is a block diagram of the dispensing apparatus which shows 1st Example of this invention. It is sectional drawing of the spacer in FIG. 1A-A 'line. It is a circuit diagram which shows the circuit of the dispensing control part of FIG. It is a time chart of the liquid level and liquid quantity detection which shows 1st Example of this invention. It is a block diagram of the dispensing apparatus which shows 2nd Example of this invention. It is a time chart of the liquid level and liquid quantity detection which shows 2nd Example of this invention. It is a block diagram which shows the conventional dispensing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Dispensing control part 11 Pump drive mechanism 12 Manifold 13 Inner conductor 14 Outer conductor 15 Spacer 16 Nozzle 17 Lifting mechanism 18 Air gap 19 Inner conductor air gap 20 Sample 21 Sample container 22 Coating film 30 Radiation wave generation circuit 31 Reflected wave detection circuit 32 Comparison circuit 33 Time delay detection circuit 34 Arithmetic circuit 35 Liquid amount detection circuit 36 Signal output circuit 40 Radiation signal 41 Reflection signal 42 Liquid contact signal 43 Liquid amount adjustment signal 50 Ultrasonic sensor 51 Nozzle tip 52 Nozzle head 53 Ultrasonic 60 Pump Drive control signal 61 Lift control signal

Claims (9)

In a dispensing method in which the liquid in the sample container is sucked into the nozzle, the liquid level in the nozzle is detected, a predetermined amount of sample liquid is sucked, and then discharged and distributed to another container.
The amount of the sample liquid is provided with an electrode pair serving as a distributed constant line in the nozzle, a radiated wave is applied between the electrodes, a delay time between a radiated signal due to the radiated wave and a reflected signal of the reflected wave, and the reflected signal A dispensing method characterized by detecting and obtaining an amplitude value.   The dispensing method according to claim 1, wherein the reflected signal is caused by a change in impedance value generated when the nozzle contacts the sample interface and when the sample is sucked into the nozzle. A nozzle for sucking the liquid in the sample container; a liquid amount detecting means for detecting a liquid amount by detecting a liquid level in the nozzle; a pump driving unit for sucking and discharging the sample; and the nozzle or the sample container. In a dispensing apparatus comprising: a transport unit that moves; a control unit that controls the liquid amount detection unit, the pump drive unit, and the transport unit;
The liquid amount detecting means includes a distributed constant line composed of an electrode pair provided on the nozzle, a radiated wave generating circuit for applying a radiated wave connected to one of the electrode pair, and a reflected wave connected to the other of the electrode pair. A detection circuit; a liquid amount calculation circuit for detecting a liquid amount by detecting an amplitude value and a delay time between the radiation signal by the radiated wave and the reflected signal of the reflected wave; and the pump driving unit at the time of liquid contact with the sample interface A dispensing device comprising a comparison circuit that outputs a signal.   The nozzle includes a cylindrical inner conductor, a spacer made of an insulating material provided on an outer peripheral portion of the inner conductor, and a cylindrical outer conductor provided coaxially with the inner conductor on the outer peripheral portion of the spacer. The dispensing device according to claim 3.   The dispensing apparatus according to claim 4, wherein the spacer has a plurality of gaps arranged radially about the axis of the inner conductor.   6. The dispensing device according to claim 4, wherein the spacer obtains a constant characteristic impedance according to a relative dielectric constant and the number of the spacers.   The dispensing device according to any one of claims 4 to 6, wherein the spacers are arranged in an upper part and a central part in a vertical direction of the nozzle.   The dispensing device according to any one of claims 3 to 7, wherein the electrode pair constituting the nozzle has a coating film for anticorrosion on a surface thereof.   The dispensing apparatus according to any one of claims 3 to 8, wherein the radiation wave generation circuit generates a pulse having a rise time and a pulse width of sub-μs or less of the radiation wave.

Images