JPH0263183B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a particle counting device that counts particles while distinguishing them by size, and is particularly useful for counting red blood cells and platelets in blood.

Configuration of conventional examples and their problems Conventionally, as a device for optically measuring fine particles,
Applying the principle of dark-field microscopy, a lens focuses light from a laser or other device close to the detected particle, and when there are no particles within the focus, there is no light output, and when a particle enters, the scattered light from it is collected. Devices that emit light, perform photoelectric conversion, and detect particle signals are known.

The strength of the scattered light is determined not only by the size of the particles but also by
Since conditions such as the reflectance of the particle surface, the shape, and the rotational movement of the particle are added, it is not appropriate to discriminate the size of the particle based only on the pulse height of the particle signal. Therefore, the pulse width of the signal pulse is also used as a signal element, and this is used in combination with the pulse height element to relatively reduce the influence of the error element and improve signal discrimination accuracy.

The pulse width element mainly depends on the velocity of the particles passing through the focal point, and since the particles are suspended in the liquid, there are many fluctuation factors such as liquid temperature, viscosity, pipe resistance, and liquid flow pressure. , which was a source of error in conventional equipment.

OBJECT OF THE INVENTION An object of the present invention is to provide a particle counting device with high signal discrimination accuracy by detecting particle velocity and improving pulse width detection accuracy.

Structure of the Invention The particle counting device of the first invention includes a means for sending a liquid containing particles to be detected, and a particle counting device that detects passage of the particles in a flowing liquid and outputs a pulse signal corresponding to the size of the particles. A detection means, a discrimination means for discriminating the particle size from the height and width of the pulse signal, and a counting means for counting the number of pulse signals (number of particles) for each particle size, wherein the velocity detection means of the flowing liquid; and control means for controlling the liquid delivery means so that the velocity of the flowing liquid is kept constant based on the detection result of the speed detection means.

According to this configuration, even if the speed of the liquid and therefore the particles changes due to changes in the liquid temperature, viscosity, pipe resistance, liquid flow pressure, etc., which are error factors in the width of the pulse signal, the speed By driving the liquid delivery means and adjusting its delivery pressure by means of the detection means and the control means, the velocity of the liquid, and therefore of the particles, can be automatically returned to the original predetermined velocity.

That is, the negative influence from error sources is virtually removed, and the width of the pulse signal is reduced to the particle size (granularity).
This makes it possible to detect the image as one that accurately corresponds to the . This makes it possible to increase the accuracy of counting the number of particles for each particle size.

A particle counting device according to a second aspect of the invention includes: a means for sending a liquid containing particles to be detected; and a particle detecting means for detecting passage of the particles in the flowing liquid and outputting a pulse signal corresponding to the size of the particles. , comprising a discrimination means for discriminating the particle size from the height and width of the pulse signal, and a counting means for counting the number of pulse signals (number of particles) for each particle size, the velocity detection means for the flowing liquid; and pulse width correction means for correcting the width of the pulse signal based on the detection result of the detection means.

According to this configuration, even if the error factor for the pulse signal fluctuates and the particle velocity fluctuates, the velocity detection means and the pulse width correction means correct the pulse width error caused by the particle velocity fluctuation. The pulse width can be corrected automatically to the original pulse width.

That is, the negative influence from error sources is virtually removed, and the width of the pulse signal is reduced to the particle size (granularity).
This makes it possible to detect the image as one that accurately corresponds to the . This makes it possible to increase the accuracy of counting the number of particles for each particle size.

Description of Embodiments (-1) A first embodiment of the first invention will be described based on FIGS. 1 to 3.

FIG. 1 is a conceptual diagram of the overall configuration of a particle counting device. This device includes a detection unit 11 that focuses light on a narrow flow of sample suspension, captures light scattered by particles, performs photoelectric conversion, and generates a particle signal pulse, an amplifier circuit 12 that amplifies the pulse, and a signal pulse. After A/D converting the height and width of , the discrimination circuit 13 multiplies the two and discriminates the product in the storage section of PROM, and the counting circuit 1 counts each discrimination pulse.
4, a display circuit 15 that displays the counting results, and a power supply section (not shown) that supplies power to each section.

The sample suspension used is, for example, blood diluted 500 to 20,000 times with a diluent (mainly containing physiological saline).

FIG. 2 shows a more specific configuration of the particle detection section 11 and the discrimination circuit 13. 1 is a container for a suspension (sample) of particles to be tested; 16 is a suction pipette immersed in the container 1; a cylinder 4 is connected to this pipette; and electromagnetic valves 2, 3 is interposed. M is a drive motor for the cylinder 4.

Reference numeral 6 designates a detection tube, in which a fine opening at the tip of a suction pipette 16 is located at the center of the detection tube, and a delivery tube 7a of a sheath liquid tank 7 is connected to the lower part thereof. Inside the detection tube 6, the sheath liquid S flows in a sheath shape around the flow of the sample, and the particles flow in a line through the center of the tube.

The sheath liquid tank 7 is configured in an airtight manner, and an air supply pipe 7b from the compression pump CP is connected thereto, and a solenoid valve 8 is interposed in the middle of the air supply pipe 7b. The compression pump CP includes a pressure regulator 10, and a needle valve of the pressure regulator 10 is configured to be adjusted in and out by a servo motor SM. The tank 7, the pump CP, the delivery pipe 7b, and the like constitute a sample delivery means 29.

A light emitting laser LA including a lens system and a light receiving photodiode PD including a lens system are disposed in a portion of the detection tube 6 where particles flow in a line, and these constitute a particle detection section 11.

A thin tube 6a is led out from the detection tube 6, and the thin tube 6a
A branch pipe 9 from the delivery pipe 7b is connected in the middle, and a solenoid valve 5 is interposed in the branch pipe 9. The electromagnetic valve 5 is opened instantaneously, and when the valve is opened, one small bubble is injected from the branch pipe 9 into the thin tube 6a. 17 is an outlet of the thin tube 6a, and 18 is a drain container.

The particle velocity detection means 30 is constructed as follows. That is, on the thin tube 6a, a plurality of pairs of light emitting elements (light emitting diodes) H and light receiving elements (photodiodes) J are arranged at equal intervals P ₁ , P ₂ . . .
Pn is installed in parallel to detect the passage of air bubbles flowing at the same speed as the liquid. Each light receiving element J is connected to a microcomputer (hereinafter referred to as microcomputer) MC.

The microcomputer MC is configured as follows.
That is, as shown in the time chart of FIG. 3, the bubble detection pulse sent from each light-receiving element J is converted into a bubble pulse φ ₁ of a constant width within the microcomputer MC.
It is shaped into φ ₂ , ... φn, and a gate pulse is created. This gate pulse controls the counting of clock pulses. There is a counter A in the microcomputer MC.
and a resistor R, and a resistor R for the pair of light emitting and light receiving elements.
While the bubbles flow from P ₁ to P ₂ , counter A
counts the clock pulses, and when it is finished, it is transferred to register R and reset, and then counts again from P ₂ to P ₃ . After that, the process is repeated until Pn.

The resistor R is connected to the D/A converter DA,
The count value is converted to DC voltage and the servo amplifier
It is used as an input for SA.

The servo amplifier SA drives a servo motor SM, and the servo motor SA is configured to adjust the needle valve of the pressure regulator 10 to control the positive air pressure generated by the compression pump CP. When the liquid flow slows down and the number of clock pulses on counter A increases, the servo amplifier
The input voltage of the SA increases, the needle valve of the pressure regulator 10 is rotated in the closing direction, the positive air pressure applied to the detection tube 6 is increased, and the liquid flow rate is increased. When the bubble passes through the light emitting/receiving element pair Pn at the final stage, a driving pulse for the solenoid valve 5 is output from the control circuit CC to inject the next bubble. Microcomputer
MC, D/A converter DA, servo amplifier SA, servo motor SM, and pressure regulator 10 constitute speed detection means 31.

The control circuit CC is configured to drive and control the solenoid valves 2, 3, 5, and 8, the cylinder drive motor M, and the compression pump CP. The initial drive of the compression pump CP is performed by causing the counter A to count a predetermined pulse in response to an ON signal from the manual start switch 19.

Next, the discrimination circuit 13 will be explained.

The pulse signal from the amplifier circuit 12 is sent to a first converter that converts the pulse height H into a digital signal.
Sent to _BH . This A/D converter _BH first holds the pulse peak, creates a time width pulse according to the peak value using an integrating circuit, and sends a clock pulse from the transmitting circuit 22 to the data latch circuit 25 according to the time width. send out. Timing generation circuit 2 generates a conversion end signal every time transmission is completed.
Send to 4.

On the other hand, the pulse signal from the amplifier circuit 12 is also sent to the comparison circuit 21. The comparison circuit 21 has a predetermined comparison voltage E, generates a time width pulse only while the pulse signal is higher than the pulse signal, and sends it to the gate circuit 23.

The gate circuit 23 includes the transmitter circuit 22 and the comparator circuit 2.
The two inputs of 1 are ANDed and a clock pulse corresponding to the pulse width W of the particle pulse signal is sent to the latch counter circuit 26. A conversion completion signal is sent from the comparison circuit 21 to the timing generation circuit 24 every time the transmission is completed.

The above comparison circuit 21 and gate circuit 23 constitute the second A/D converter _BW .

The memory consists of PROM, a writable read-only memory.

The counter of the data latch circuit 25 is
It is connected to the lower half of the address counter indicating the memory address of PROM.M, and the counter of the latch counter circuit 26 is connected to the upper half of the address counter.

The value of the product of the pulse width value of the latch counter circuit 26 and the pulse height value of the data latch circuit 25, and a value indicating another weighted division, are stored in advance at the memory address indicated by the address counter.

The timing generation circuit 24 receives the conversion end signal from the first A/D converter _BH and the comparison circuit 21, and the no-overflow signal from the data latch circuit 25 and the latch counter circuit 26, and resets the PROM.M. send a signal.

When a reset signal is input from the timing generation circuit 24 to the PROM.M, a signal corresponding to the value stored at the address is outputted to the microcomputer 28.
The microcomputer 28 has built-in a large number of channels C and counters D according to granularity.
The output signal from the PROM・M is the corresponding 1
The signal is input to only one channel C, and the corresponding counter D is incremented by +1.

The PROM-M and its preceding circuit section are means for discriminating the particle size from the height H and width W of the pulse signal in the configuration of the invention, and the PROM-M and the microcomputer 28 are the means for discriminating the particle size from the height H and width W of the pulse signal according to the structure of the invention. ). The more specific structure of PROM.M is the same as that of the related prior application, Japanese Patent Application No. 1987-197787.

The operations of particle detection and particle velocity detection and velocity control are as follows.

Upon receiving the manual start signal from the switch 19, the control circuit CC operates and opens the solenoid valve 2.
The piston of the cylinder 4 is driven by a motor M to aspirate the sample.

After suctioning a predetermined amount, the solenoid valve 3 is opened, the solenoid valve 2 is closed, the motor M is reversed, and the sample is injected into the detection tube 6.

At the same time, open the solenoid valve 8 and press the compressor pump.
The sheath liquid S is forced into the detection tube 6 by driving the CP and sending positive air pressure to the sheath liquid tank 7 storing the sheath liquid.

Particles in the sample are detected by the detection unit 11, and the pulse signals are sent to the first and second A/D converters.
The signals are input to B _H and B _W , and the above-mentioned discrimination processing is performed.

On the other hand, when the control circuit CC pulses the solenoid valve 5 during measurement and opens it momentarily, the compressor pump
One small bubble enters the capillary tube 6a due to the CP.

Bubbles are detected by the pair of light emitting/receiving elements P ₁ to Pn, and the detection pulse is input to the microcomputer MC, which controls the pressure regulator 10 via the servo motor SM through the above-mentioned operation, and controls the compression pump CP. Adjust the positive air pressure. That is, feedback control is performed so that the particle velocity is always kept constant. Note that in FIG. 2, functional diagrams of the air filter and sheath fluid replenishment/cleaning are omitted.

Note that the arrangement of the light-emitting/light-receiving element pairs P ₁ to Pn must be electrically adjusted in advance to be equally spaced.
In addition, depending on the case, a counting circuit 14, a display circuit 15
may occur in parallel.

As a modification of this embodiment, (1) the bubble injection means is made into a separate system from the compression pump CP, and (2) the bubbles are injected at regular intervals and the number of emitting/receiving element pairs is one. is also valid.

(-2) A second embodiment of the first invention will be explained based on FIGS. 4 and 5.

Outlet 1 of thin tube 6a from detection tube 6 (not shown)
7 is used as a fine opening so that the sample is discharged in the form of droplets, and only one pair _P1 of a light-emitting element H and a light-receiving element J is arranged in the drop path, and the light-receiving element J is connected to a microcomputer. Connected to MC. The light-receiving element J is for detecting the passing time interval between successive drops of liquid in the gap between them and detecting the speed thereof.

That is, the pulse detected at the gap is shaped by the microcomputer MC into φ ₁ . Counter A counts clock pulses and transfers them to register R after counting, and register R is input to D/A converter DA, converted to a DC voltage, and becomes input to servo amplifier SA. The branch pipe 9 and solenoid valve 5 of the first embodiment are not provided. The rest is the same as the first embodiment. When stopping for a long time, use the exhaust port 17.
Immerse it in liquid to prevent it from drying out.

In this embodiment, the pair of light emitting and light receiving elements P1 is ₁
Furthermore, since the branch pipe 9 and the electromagnetic valve 5 are not required, the structure is simpler than that of the first embodiment. On the other hand, in the case of the first embodiment, air bubbles are injected into the closed system and the speed is detected in the closed system, so there is no influence from the atmosphere, and in this respect, it is better than the second embodiment. It also has the advantage of high counting accuracy.

Note that instead of detecting the passage of the droplet through the gap, the passage of the droplet itself may be detected.

(-1) A first embodiment of the second invention will be explained based on FIGS. 6 and 7.

In this case, the output voltage from the D/A converter DA is used as the reference input of the comparator circuit 21. As the particle velocity decreases, the reference input becomes higher and the pulse width input to the gate circuit 23 is reduced. In other words, as shown in Fig. 7, when the particle speed slows down, the pulse width H _L becomes larger than the pulse width H _N at the specified speed, causing an _error . By _lowering the input pulse width to the gate circuit 23 from
This means that H _G is corrected to a specified pulse width H _N.
The microcomputer MC, the D/A converter DA, and the reference voltage terminal of the comparator 21 constitute a pulse width correction means 32. The rest is the same as the first embodiment of the first invention.

In the case of the embodiment of the first invention, the compressor pump CP
The positive air pressure is adjusted to keep the flow velocity constant, but this adjustment causes a small amount of pulsation, which limits the improvement of counting accuracy. On the other hand, in this embodiment of the second invention, since the flow velocity is not changed, counting can be performed with higher accuracy.

(-2) To explain the second embodiment of the second invention, the same means as in the second embodiment ( _-2 ) of the first invention (see Fig. 4) is adopted as a particle velocity detection means. This is what I did. The rest is the same as the second embodiment ( _-2 ).

In addition, it may be configured to activate an alarm when the flow velocity falls outside of a predetermined range and re-measure, or monitor the DC voltage of the D/A converter DA and manually adjust the pressure or set the reference voltage. Adjustments may also be made.

Further, in the microcomputer 28,
It is also possible to configure the flow volume to be determined from the average flow velocity and flow time.

Effects of the Invention According to the first and second inventions, liquid temperature, clay, pipe resistance, liquid flow pressure, etc., which are error factors in the width of a pulse signal, which is an element for particle size detection, are both Even if the particle velocity fluctuates as a result, the adverse effects from error factors can be substantially removed by velocity control (first invention) or pulse width correction (second invention), This has the effect of improving the accuracy of counting the number of particles by particle size.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of the overall configuration of the first embodiment of the first invention, FIG. 2 is a specific configuration diagram of the main parts,
Fig. 3 is a time chart explaining its operation, Fig. 4 is a configuration diagram of the main part of the second embodiment of the first invention, Fig. 5 is a time chart explaining its operation, and Fig. 6 is a time chart of the second embodiment of the first invention. Configuration diagram of main parts of the first embodiment of the invention, No. 7
Figures A, B, and C are waveform diagrams illustrating the operation. 11... Particle detection unit (means), 13... Discrimination circuit (means), 14... Counting circuit (means), 29...
...Liquid delivery means, 30...Liquid speed detection means, 31...
...Speed control means, 32...Pulse width correction means.

Claims (1)

[Scope of Claims] 1. A means for sending a liquid containing particles to be detected, a particle detecting means for detecting passage of the particles in the flowing liquid and outputting a pulse signal corresponding to the size of the particles, and a discrimination means for discriminating the particle size from the height and width of the signal, a counting means for counting the number of pulse signals (number of particles) for each particle size, and a speed detection means for the flowing liquid;
and control means for controlling the liquid delivery means so that the velocity of the flowing liquid is kept constant based on the detection result of the speed detection means. 2. The flowing liquid speed detecting means is composed of a means for injecting bubbles into the flowing liquid, and a bubble speed detecting means for detecting the passage of the bubbles at a plurality of points in the course of the flow of the liquid and detecting the speed thereof. A particle counting device according to claim 1, which is a particle counting device according to claim 1. 3. Dripping means in which the speed detection means of the flowing liquid discharges the flowing liquid in the form of droplets, and a dropping means in which the speed is detected by detecting the passing time interval of successive dripping liquids in the gap between successive dripping liquids. 2. A particle counting device according to claim 1, comprising liquid gap velocity detection means. 4. A means for sending a liquid containing particles to be tested, a particle detecting means for detecting the passage of the particles in the flowing liquid and outputting a pulse signal corresponding to the size of the particle, and a means for detecting a pulse signal based on the height and width of the pulse signal. a discrimination means for discriminating particle size; a counting means for counting the number of pulse signals (number of particles) for each particle size; and a speed detection means for the flowing liquid;
and pulse width correction means for correcting the width of the pulse signal based on the detection result of the speed detection means. 5. The flowing liquid speed detecting means is composed of a means for injecting bubbles into the flowing liquid, and a bubble speed detecting means for detecting the passage of the bubbles at a plurality of points in the flow course of the liquid and detecting the speed thereof. A particle counting device according to claim 4, which is a particle counting device according to claim 4. 6. Dripping means in which the speed detection means of the flowing liquid discharges the flowing liquid in the form of droplets, and a dropping means in which the speed is detected by detecting the passing time interval of successive dripping liquids in the gap between successive dripping liquids. 5. A particle counting device according to claim 4, comprising liquid gap velocity detection means.