JPH03150445A - Particle analyzing device - Google Patents

Abstract

PURPOSE:To take a measurement in a short time with high accuracy by making a scan while plural beams emitted by an acoustooptic element are made out of phase, and measuring an obtained optical signal and analyzing a particle to be inspected. CONSTITUTION:The device is provided with a means which makes light beams from laser light sources 2 and 3 incident on different positions X1 and X2 of the acoustooptic element 4 and makes a scan while making the light beams, emitted by the acoustooptic element 4, different in scanning direction. Then the acoustooptic element 4 is used to make a scan on the particle to be inspected in fluid with the laser beams at right angles to the moving direction, and the obtained optical signal is measured to analyze the object particle.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention, like a flow cytometer, irradiates test particles passing through a flow cell with a laser beam or the like, and collects optical signals from the test particles. This invention relates to a particle analysis device that detects and analyzes the properties, structure, etc. of particles to be detected.

[Conventional technology] A flow cytometer is a cell suspension solution that flows at high speed.
In other words, it is a device that irradiates a sample liquid with, for example, a laser beam, detects a photoelectric signal from the scattered light, and elucidates the properties and structure of cells, and is used in fields such as cytochemistry, immunology, hematology, oncology, and genetics. used in

In conventional particle analysis devices used in flow cytometers and the like, for example, 200 μm x 2
A laser beam or other light is irradiated onto test particles, such as blood cells, passing through a flow section with a minute rectangular cross section of 00 μm while being wrapped in a sheath fluid, and the resulting forward and side scattered light is used to Shape/size/
It is possible to obtain particle-like properties such as refractive index. Also,
For test particles that can be stained with a fluorescent agent, important information for analyzing the test particles can be obtained by detecting the fluorescence from the test particles along with side scattered light in a direction almost perpendicular to the irradiation light. You can ask for it.

Conventionally, this type of device uses a photodetector to detect the forward scattered light generated by irradiating a laser beam from a single direction onto the particles flowing through the fluid in the flow section, thereby determining the size of the particles. Measuring. However, the test particles in the flow section are scattered in the direction perpendicular to the flow, and the position of each test particle deviates from the intensity distribution of the laser beam, and the amount of light irradiated on the test particle changes, so the scattered light intensity includes the influence of variations in the position of the particles being tested.

Although this drawback can be compensated to a considerable extent by employing the sheath flow method, delicate adjustment operations are essential to accurately align the center of the flow with the center of the laser beam intensity distribution in advance. Therefore, in order to eliminate the need for this adjustment operation and to prevent variations in the position of the particles to be detected in the fluid from affecting the scattered light intensity, the irradiated laser beam is moved in a direction perpendicular to the flow of the particles to be detected. Particle analysis devices that perform similar detection by scanning have been proposed. It is known to perform this scanning using an acousto-optic device (AOD), which deflects the laser beam by inputting the laser beam to an acousto-optic device whose deflection angle changes by changing the applied voltage. This is used for scanning.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional example, there is a limit to the scanning speed of the laser beam using the acousto-optic element. In order to measure accuracy, a method is adopted in which the flow velocity of the particles to be measured is slowed down. However, in order to analyze the test particles, it is necessary to measure and perform statistical processing on a large number of test particles, so if the flow rate is slowed down, the measurement will take a considerable amount of time.

An object of the present invention is to eliminate the above-mentioned drawbacks and provide a particle analysis device that can perform highly accurate measurements in a short time.

[Means for Solving the Problems] In order to achieve the above object, in the particle analysis device according to the present invention, an acousto-optic element is used to apply a plurality of light beams to the test particles in the fluid in a direction intersecting the flow. In a particle analysis device that scans a beam and measures the obtained optical signal to analyze a target particle, the plurality of light beams are incident on different positions of the acousto-optic element and emitted from the acousto-optic element. It is characterized by having means for scanning by shifting the scanning directions of a plurality of light beams.

[Operation] The particle analysis device having the above configuration uses an acousto-optic element to scan the test particles in a fluid with a plurality of laser beams in a direction perpendicular to the direction of movement of the particles, and generates optical signals. Measure and analyze the target particles.

[Example] The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 is a diagram showing the configuration of an apparatus according to an embodiment of the present invention.
is a flow cell, and the test particles flow together with the sheath liquid at a high speed through this flow section 1a. Flow cell 1 from two laser light sources 2.3 installed in parallel
Optical path 0 of laser beams L1 and L2 emitted toward
1.02, an acousto-optic element 4 composed of a piezoelectric material 4a and a medium 4b, and a condensing lens 5 are provided, and the laser beams L1 and L2 are made to enter different positions of the medium 4b. ing. In addition, in order to measure the forward scattered light of the laser beams L1 and L2 caused by the test particles in the flow section la, a condenser lens 6, A photodetector 7 is provided, the output of the photodetector 7 is connected to a signal processing device 8, and the output of the signal processing device 8 is connected to a storage device 9. Further, a sweep oscillator 10 and a power source 11 are sequentially connected to the acousto-optic element 4 for controlling the deflection angle.

Laser beam L1 emitted from laser light source 2.3
, L2 are respectively incident on the positions x1 and x2 of the medium 4b in the optical path, are deflected, and after passing through the condensing lens 5 are sent to the circulation part l.
The forward scattered light is received by the photodetector 7 via the condensing lens 6, and the amount of received light is calculated into the necessary information about the particle in the signal processing device 8. After being processed, it is stored in the storage device 9.

When an AC voltage with a frequency f is applied to the piezoelectric material 4a of the acousto-optic element 4, an ultrasonic wave with a wavelength inversely proportional to the frequency f is generated at the end A of the medium 4b, and the ultrasonic wave is transmitted through the medium 4b from the end A to the end. Propagates to B. A diffraction grating is formed by the wavefront of this ultrasonic wave, and the laser beam L1. L
2 is deflected by this grating. By changing the frequency f applied to the piezoelectric material 4a and changing the interval of the diffraction grating formed in the medium 4a, the incident laser beam L1,
The deflection angle of L2 can be changed, and the laser light source L1
, L2 can be scanned in the horizontal direction.

As shown in FIG. 2, a time-varying sawtooth voltage is applied from the power supply 11 to the sweep oscillator IO, and the sweep oscillator 10 converts it into an alternating current voltage with a frequency proportional to this voltage. added to. Therefore, ultrasonic waves whose wavelengths change periodically are generated one after another at the end A in the medium 4b, propagate through the medium 4b toward the end B, and form a diffraction grating. For this reason, the spacing of the diffraction gratings at positions xi and x2 at the same time is different, so
Even if the laser beams Ll and L2 have the same wavelength, the deflection angles will differ depending on the incident position, and the test particles will be scanned at different timings. In other words, the laser beams L1 and L enter different positions of the medium 4b due to parallel light.
2 and 2 by periodically shifting the phase in different directions, the circulation part 1a can be scanned, and when the laser beam Ll is at the position Lla, the laser beam L2 is at the position L2b.
When the laser beam L1 is at the position Llb, the laser beam L2 is at the position L2c, and when the laser beam L1 is at the position Llc, the laser beam L2 is at the position L2a.

When scanning is performed using only one laser light source as in the conventional example, the amount of light received by the photodetector 7 is as shown in FIG. 3(a), and even if the scanning time is shortened, the laser beam Scattered light is not received while it is not being scanned.

However, when two laser light sources 2.3 are used, the distance between the laser light sources 2 and 3 that are installed in parallel, that is, the incident positions x1 and x of the laser beams L1 and L2 on the medium 4b.
2 and the period of voltage change to the acousto-optic element 4, and reverse the scanning phases of the laser beams L1 and L2, the amount of light received by the piezoelectric material 4a is as shown in Fig. 3 (bl). As shown, by alternately receiving the laser beams L1 and L2, scanning can be performed even during a time when scanning could not be performed in the conventional example.

Although it is not possible to shorten the time required to scan one laser beam using the acousto-optic element 4, it is not possible to shorten the time required to scan one laser beam. ．． 1. By using L2, highly accurate measurement can be achieved in a short time with the same effect as doubling the scanning speed.

In addition, although the laser beams L1 and L2 are collimated, even if they are not parallel lights, if they are incident on different positions x1 and x2 of the medium 4b, and the angles formed at the incident positions of the laser beams I, 1, and L2 can be detected. Similar measurements are possible. Also,
Although scanning was performed with the phases of the two laser beams L1 and L2 reversed, it would be possible to achieve even greater accuracy by performing similar measurements using multiple, for example three, laser light sources and shifting the phases of the laser beams by 120 degrees. This makes it possible to measure a high degree of

The wavelengths of the two laser beams L1 and L2 used in this case may be the same or different, and although two laser light sources are used in this embodiment, the laser beam from one laser light source is The same effect can be obtained even if the light is guided as parallel light and incident on different positions x1 and x2 of the medium 4a.

[Effects of the Invention] As explained above, the particle analysis device according to the present invention irradiates the target particles by scanning the plurality of laser beams with the phase shifted using an acousto-optic element, so it can be used for a short time. allows for highly accurate measurements.

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[Brief explanation of the drawing]

The drawings show an embodiment of the particle analysis device according to the present invention, in which Fig. 1 is a configuration diagram, Fig. 2 is an explanatory diagram of power supply voltage change, and Fig. 3 (a), fbl shows the amount of light received by the photodetector. It is a graph diagram. Symbol l is a flow cell, 2.3 is a laser light source, 4 is an acousto-optic element, 4a is a piezoelectric material, 4b is a medium, 7 is a photodetector,
10 is a sweep oscillator, and 11 is a power supply.

Claims (1)

[Claims] 1. Analyze the particles by scanning the particles in the fluid with a plurality of light beams using an acousto-optic device in a direction intersecting the flow, and measuring the obtained optical signal. The particle analysis device is characterized by comprising means for making the plurality of light beams incident on different positions of the acousto-optic element and scanning the plurality of light beams emitted from the acousto-optic element by shifting the scanning direction of the plurality of light beams. Particle analysis device. 2. The particle analysis device according to claim 1, wherein the optical paths of the plurality of light beams before scanning are parallel light beams that are on a plane perpendicular to the flow of the particles to be detected and separated by a certain distance.