JP4046446B2 - Particle analyzer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a particle analyzer, and more particularly to a particle analyzer that obtains a plurality of parameters from each particle and creates a distribution map.
[0002]
[Prior art]
In reactive particles (particles using a chemical reaction) typified by adsorbed particles such as activated carbon, the size of the surface area of the particles affects the ease of reaction. That is, the more uneven the particle surface, the larger the surface area and the more advantageous the reaction.
Therefore, in the field concerning such particles, a method using an SEM (scanning electron microscope) is known for analyzing the surface state of the particles.
Also known is an apparatus that analyzes the morphology of each particle by observing a particle image obtained by flowing a particle-containing liquid into a flow cell using a flow cytometry method and imaging the particle (for example, JP-A-8-178826).
[0003]
[Problems to be solved by the invention]
By the way, in order to observe the particles with the SEM, the target particles must be conductors. Therefore, the insulator particles are observed after gold vapor deposition. Therefore, there is a problem that not only the true surface state cannot be observed but also it is difficult to analyze a large amount of particles in a short time.
Furthermore, even when particles are imaged and analyzed by the flow cytometry method, it is necessary to observe the imaged particle image with an operator's visual observation, and thus there is a problem that analysis takes time.
[0004]
The present invention has been made in consideration of such circumstances, and particle information that has been difficult to know by a conventional method, for example, information such as particle surface state can be efficiently known. An analyzer is provided.
[0005]
[Means for Solving the Problems]
The present invention provides a flow cell for flowing a sample liquid containing particles in a thin sample liquid flow, a light detection unit for detecting light emitted from each particle in the first flow region of the sample liquid flow, and the above in the second flow region of the sample liquid flow. An imaging unit that captures a particle image of each particle, a first feature parameter generation unit that determines a first feature parameter from the detected light, and a second feature parameter generation that calculates a second feature parameter from the captured particle image An analysis unit that creates a particle distribution map based on the first and second characteristic parameters and analyzes the distribution map, and an output unit that outputs the analysis result . The first characteristic parameter indicates the scattered light intensity. is a parameter that reflects, in which the second characteristic parameter providing Oh Ru particle analyzer with a parameter which reflects the projected area.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
As the flow cell of the present invention, it is preferable to use a flow cell capable of forming a thin sample liquid flow by a hydrodynamic effect by wrapping and flowing a sample liquid containing particles in a sheath liquid.
[0007]
The particles targeted by the particle analyzer of the present invention may be industrial powders such as activated carbon, pigments and toners, and particle components such as blood cells and cells contained in blood and urine may be measured. The target particles include those having a particle size of about 0.1 to 100 μm as an example.
[0008]
The light detection unit for detecting the light emitted by each particle in the first flow region is illuminated by a light source (for example, a continuous light source that continuously emits light such as a laser, a halogen lamp, or a tungsten lamp) in the first flow region of the sample flow. It can be constituted by a photodetector (for example, a photodiode, a phototransistor, or a photomultiplier) that outputs the intensity of light such as scattered light or fluorescence from the particles.
[0009]
It is preferable to provide a light source that irradiates light to the second flow area of the sample flow for imaging, which includes a continuous light source that continuously emits light, such as a laser, a halogen lamp or a tungsten lamp, or a pulse. A continuous light source that irradiates light intermittently, such as a laser (for example, 7000 series manufactured by Spectra-Physics) or a multi-strobe (for example, DSX series manufactured by Ebara Laboratories, Inc.) can be used. In general, it is preferable to use a continuous light source as a continuous light source in combination with an optical shutter. As the optical shutter, a known acousto-optic modulator, electro-optic modulator, or the like can be used.
[0010]
A video camera that captures a general two-dimensional image may be used for the imaging unit that captures the particle image. However, when the light amount of the optical image is weak, image intensity that enhances the weak optical image is used. It is preferable to use one provided with a fire. Further, the image intensifier may be provided with shutter means. The second basin may be downstream of the first basin or in a similar position.
In order to detect light such as scattered light and capture an image with respect to the same particle, it is preferable to capture an image with an imaging unit based on the light detection with the photodetector.
[0011]
A display device such as a CRT, a liquid crystal display, or a printer can be used for the output unit. The first and second feature parameter generation units can be configured by a signal processing device including an A / D converter and a logic circuit. The analysis unit can be configured by a microcomputer or personal computer including a CPU, a ROM, and a RAM. The distribution map is a general term for what expresses the distribution state of particles by a characteristic parameter, and a suitable example is a two-dimensional scattergram.
[0012]
In the present invention, the forward scattered light intensity, the side scattered light intensity, the fluorescence intensity, or the like can be used as the first characteristic parameter. Further, as the second feature parameter, a projected area, a circle equivalent diameter, a circularity, or the like obtained from the particle image can be used.
[0013]
【Example】
An optical system according to an embodiment of the present invention is shown in FIGS. In this embodiment, two light sources, a continuous light emitting laser light source 1 for detecting forward scattered light and a pulse light source 2 for capturing a particle image, are provided. As shown in FIG. 2, the lights L1 and L2 from the two light sources 1 and 2 are orthogonal to each other with respect to the rectangular sheath flow cell 3 (in FIG. 1, the sample flow flows in a direction perpendicular to the paper surface). Irradiated at 90 ° crossing. Further, in this embodiment, the pulsed light for capturing the particle image irradiates the sample liquid flow in the sheath flow cell 3 downstream (for example, about 0.5 mm downstream) from the irradiation position of the continuous emission laser light source 1. Like to do. By shifting the irradiation position in this way, the influence of mutual interference of light can be reduced.
[0014]
The sample liquid containing the particles is guided to the sheath flow cell 3, and a sample liquid flow narrowed by the sheath liquid is formed. The continuous-emitting laser light is narrowed down by the condenser lens 4 and applied to the sample liquid flow, and the forward scattered light from each particle is collected by the condenser lens 5 and received by the photodiode 7.
[0015]
The scattered light signal (here, forward scattered light signal) S1 detected by the photodiode 7 is passed to the signal processing device 100 shown in FIG. 3, where the height information and width information of the pulse of the signal are A / D converted, respectively. After that, the forward scattered light intensity FSC and the forward scattered light width FSW are passed to the data processing device 300 as the first feature parameters, respectively.
[0016]
The imaging control circuit 200 shown in FIG. 3 receives the forward scattered light signal S1 and supplies a light emission trigger signal Ts for imaging the particle to the pulsed light source 2.
[0017]
The pulsed light source 2 is a type of light source that emits light for an instant (about several tens of nanoseconds) in response to a light emission trigger signal Ts, and images flowing particles without blur even when the flow rate of the sample flow is as high as several meters / second. be able to. As shown in FIG. 1, the pulsed light is guided to the flow cell 3 by the optical fiber 12, narrowed down by the condenser lens 13, and irradiated to the sample flow.
[0018]
By irradiating via the optical fiber 12, the coherency of the pulsed light can be reduced and a particle image with few diffraction fringes can be taken. The pulsed light transmitted through the sample flow is imaged on the light receiving surface of the video camera 15 by the projection lens 14, and a projected image of the particles is taken. The video signal Vs from the video camera 15 that has imaged the particles is transferred to the signal processing device 100 shown in FIG. 3, converted into digital image data, and transferred to the data processing device 300. The data processing device 300 stores the image data obtained for each particle and the first feature parameter in association with each other in the internal memory.
[0019]
The data processing apparatus 300 calculates the projection area S, the circular phase equidiameter L, and the circularity C from the projection image of each particle as the second feature parameter, and obtains a two-dimensional scattergram based on the first feature parameter and the second feature parameter. It is created and displayed on the display device 500.
[0020]
The input device 400 in FIG. 3 includes a keyboard and a mouse, and an operator operates the input device 400 to give instructions to the data processing device 300 regarding various data processing items, data processing conditions, display items on the display device 500, and the like. It can be carried out. For example, when any particle in a two-dimensional scattergram displayed on the display device 500 is designated by the input device 400, the data processing device 300 causes the display device 500 to display a projected image of the particle. The display device 500 is configured by a CRT, and the signal processing device 100, the imaging control circuit 200, and the data processing device 300 are configured by a personal computer.
[0021]
In such a configuration, when the sample liquid containing the test particles is supplied to the sheath flow cell 3 shown in FIG. 1, the particles P1, P2, P3,... Sequentially flow in the sample liquid flow as shown in FIG. When the first feature parameter and the second feature parameter are obtained for each of n particles set in advance by the input device 400, that is, the particles P1, P2, P3... Pn, the display device 500 performs two-dimensional scatter based on them. Display a gram.
[0022]
Display examples of the display device 500 are shown in FIGS.
Both are scattergrams with the vertical axis as the first feature parameter and the horizontal axis as the second feature parameter. In this embodiment, a plurality of feature parameters are obtained and stored as feature parameters. Then, by operating the input device 400, it is possible to select parameters used for creating a scattergram. In other words, the vertical axis can select either one of the forward scattered light intensity FSC and the forward scattered light width FSW, and the horizontal axis can select any one of the projection area S, the particle size L, and the circularity C. Has been. The scattergram created for the selected parameter can then be displayed.
When the parameters can be selected in this way, there is an advantage that a large number of scattergrams can be displayed even when the scattergram display space is limited. In the case of this embodiment, 2 × 3 = 6 types of scattergrams can be selectively displayed in one scattergram display area.
In the present embodiment, from the viewpoint of knowing the surface state of the particles, the forward scattered light intensity FSC is selected as the first parameter, and the projection area S is selected as the second parameter.
FIG. 4 shows a standard spherical latex particle as a test particle, which is composed of particles having a particle diameter of 0.1 to 2.0 μm, and has been confirmed in advance to have a uniform and smooth surface state. It is a thing.
In this case, the particles are distributed substantially along a straight line (A), and it can be seen that the projected area S and the forward scattered light intensity FSC are in a substantially proportional relationship.
[0023]
FIG. 5 shows an activated carbon powder whose surface state and particle size are unknown as test particles.
In this case, the particles are distributed above the straight line (A), indicating that the forward scattered light intensity is higher than that of the latex particles shown in FIG. 4, that is, the surface has many irregularities.
[0024]
FIG. 6 shows fine ceramic particles whose surface state and particle size are unknown as test particles.
In this case, the particles are widely distributed below the straight line (A), and the forward scattered light intensity is smaller than the latex particles shown in FIG. 4, that is, the surface is smoother and the variation range of the particle diameter is wide. It is shown that. In addition, about the typical thing of the particle | grains shown by FIGS. 4-6, the coordinate is instruct | indicated (sampling) with the input device 400, and each projection image is displayed on the display apparatus 500, The surface state is shown. Is also confirmed visually.
As described above, the surface state of the particles can be known efficiently.
[0025]
【The invention's effect】
According to the present invention, for each particle, a parameter based on a photodetection signal and a parameter based on a captured image are obtained to generate a distribution map, so that it is easy to know particle information that has been difficult to know in the past. be able to.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a configuration of an optical system according to an embodiment of the present invention.
FIG. 2 is a perspective view of the main part of FIG.
FIG. 3 is a block diagram illustrating a configuration of a control system according to the embodiment.
FIG. 4 is an example of a distribution diagram obtained by an example.
FIG. 5 is an example of a distribution diagram obtained by an example.
FIG. 6 is an example of a distribution diagram obtained by an example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Continuous emission laser 2 Pulse light source 3 Sheath flow cell 4 Condenser lens 5 Condensing lens 7 Photodiode 12 Optical fiber 13 Condenser lens 14 Projection lens 15 Video camera

Claims (2)

A flow cell for flowing a sample liquid containing particles in a thin sample liquid flow; a light detection unit for detecting light emitted by each particle in the first flow region of the sample liquid flow; and a particle of each particle in the second flow region of the sample liquid flow An imaging unit that captures an image; a first feature parameter generation unit that determines a first feature parameter from the detected light; a second feature parameter generation unit that calculates a second feature parameter from the captured particle image; An analysis unit that creates a particle distribution map using the first and second characteristic parameters and analyzes the distribution map; and an output unit that outputs the analysis result . The first characteristic parameter is a parameter that reflects the scattered light intensity. There, Oh Ru particle analyzer with a parameter which the second characteristic parameter reflecting the projected area.   The at least one of the first feature parameter generation unit and the second feature parameter generation unit obtains a plurality of feature parameters, and the analysis unit creates a distribution map using any of the plurality of feature parameters. Particle analyzer.

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