Particle analysis device, particle analysis system, particle analysis method, and particle analysis program

Abstract

The present invention comprises: an imaging light irradiation unit 3 for irradiating a sample with imaging light; an imaging unit 4 for imaging the sample irradiated with the imaging light; and an exposure control unit 52 for starting exposure of the imaging unit 4 during a period from when the imaging light irradiation unit 3 starts irradiation with the imaging light to when the imaging light irradiation unit 3 ends the irradiation with the imaging light, and ending the exposure of the imaging unit 4 after the imaging light irradiation unit 3 has ended the irradiation with the imaging light.

Description

Particle analysis device, particle analysis system, particle analysis method, and particle analysis program

[0001] The present invention relates to a particle analysis device, a particle analysis system, a particle analysis method, and a particle analysis program.

[0002] 2. Description of the Related Art Conventionally, there are particle analyzers that analyze the characteristics of particles contained in a sample based on an image of the sample.

[0003] This type of particle analyzer includes, for example, an LED that emits light to particles, a constant current circuit that passes a constant current through the LED, a switching element connected to the constant current circuit that turns the current flowing through the LED on and off, an imaging system that captures images of particles in cells, and an information processing device that analyzes particle characteristics from images obtained by the imaging system, as shown in Patent Document 1. When the switching element is in the on state, a constant current flows through the LED, thereby stabilizing the light intensity of the flash light from the LED.

[0004] WO2021-075310 publication

[0005] However, since it is difficult to operate a constant current circuit at high speed, the time from the start of flash light irradiation to the end of irradiation (hereinafter also referred to as irradiation time) in an LED is limited to a few microseconds at most. Therefore, it is not possible to clearly capture particles flowing at high speeds, such as 1 microsecond or less per unit length, and the captured image will be distorted.

[0006] If the irradiation time is forcibly shortened, the amount of flash light from the LED becomes unstable, causing variations in the contrast of the image captured by the imaging system, and therefore particles flowing at high speeds cannot be clearly captured.

[0007] The present invention has been made in view of the above problems, and its main object is to clearly capture images of particles flowing at high speeds.

[0008] That is, the particle analysis device of the present invention is a particle analysis device that analyzes the characteristics of particles contained in a sample based on an image of the sample, and is characterized by comprising: an imaging light irradiation unit that irradiates the sample with imaging light, which is light for imaging the sample; an imaging unit that images the sample irradiated with the imaging light; and an exposure control unit that starts exposure of the imaging unit between the time when the imaging light irradiation unit starts to irradiate the imaging light and the time when it finishes irradiating the imaging light, and that finishes exposure of the imaging unit after the imaging light irradiator unit finishes irradiating the imaging light.

[0009] With this configuration, the exposure control unit starts exposure of the imaging unit between the start and end of irradiation of the imaging light, and ends exposure of the imaging unit after irradiation of the imaging light has ended. Therefore, there is no need to shorten the time from the start to the end of irradiation of the imaging light (hereinafter also referred to as irradiation time), and the amount of imaging light can be prevented from becoming unstable. In addition, the period from the start of exposure to the end of irradiation of the imaging light (hereinafter referred to as imaging period) can be shortened compared to conventional methods. Therefore, since the imaging time can be shortened using an existing device, the amount of imaging light can be prevented from becoming unstable, and particles flowing at high speeds, such as a unit length of several microseconds or less, can be clearly imaged.

[0010] The exposure control unit may be an electronic shutter in which the start timing and / or end timing of exposure of the imaging unit is preset to a predetermined timing.

[0011] With this configuration, the exposure control unit is an electronic shutter, which allows for more accurate control of the start and end of exposure than a mechanical shutter. As a result, the exposure control unit can reliably start exposure of the imaging unit between the start and end of irradiation of imaging light and reliably end exposure of the imaging unit after irradiation of imaging light has ended, thereby ensuring the acquisition of pseudo-fast imaging light.

[0012] The imaging unit may have a plurality of light receiving elements, and the exposure control unit may be a rolling shutter that sequentially controls the start timing and / or end timing of exposure of the plurality of light receiving elements.

[0013] With this configuration, the exposure control unit is a rolling shutter, so the exposure control unit can be made less expensive than a global shutter in which multiple light receiving elements are exposed at once for the same exposure time.

[0014] The exposure control unit is preferably a rolling shutter that starts exposure of the plurality of light receiving elements at the same timing and sequentially ends exposure of the plurality of light receiving elements at mutually different timings.

[0015] With this configuration, the exposure control unit starts the exposure of the multiple light receiving elements at the same time, so compared to when the exposure of the multiple light receiving elements starts at different times, it is easy to generate a period during which all of the multiple light receiving elements are exposed before the irradiation of the imaging light ends. As a result, while with a conventional rolling shutter, image distortion occurs when the exposure of the multiple light receiving elements starts at different times, image distortion can be suppressed even with a rolling shutter.

[0016] It is desirable that the particle analysis device further includes a constant current circuit that supplies a constant current to the imaging light irradiation unit.

[0017] With this configuration, the constant current circuit passes a constant current through the imaging light irradiation unit, so that when imaging is performed under different imaging conditions, for example, the brightness of the imaging light when irradiated by the imaging light irradiation unit can be kept constant, and the imaging conditions can be made uniform.

[0018] The constant current circuit preferably performs pulse driving on the imaging light irradiating section, causing the imaging light irradiating section to oscillate the imaging light in a pulsed manner.

[0019] With this configuration, the constant current circuit performs pulse driving on the imaging light irradiator, causing the imaging light irradiator to oscillate the imaging light in pulses, so the constant current circuit can control the imaging light irradiator with less jitter.

[0020] Another aspect for controlling the imaging light irradiator with less jitter is to further include a switching element connected to the constant current circuit to turn on and off the current flowing through the imaging light irradiator.

[0021] It is preferable that the particle analyzer further includes a dry cell through which the sample containing a gaseous dispersion medium flows or is accommodated, and that the imaging unit images the sample flowing through the dry cell.

[0022] With this configuration, particles flowing through the dry cell are faster than particles flowing through the wet cell, so while conventional particle analysis devices are prone to distorting images of particles flowing through the dry cell, the particle analysis device of the present invention can suppress distortion in images of particles flowing through the dry cell.

[0023] A particle analysis system for analyzing the characteristics of particles contained in a sample, comprising the particle analyzer and a particle size distribution measuring device for measuring the particle size distribution of particles contained in the sample. A particle analysis method for analyzing the characteristics of particles contained in the sample based on an image of the sample, comprising: irradiating the sample with imaging light, imaging the sample irradiated with the imaging light, starting exposure between the start and end of irradiation of the imaging light, and ending exposure after the end of irradiation of the imaging light. A particle analysis program for use in a particle analyzer comprising an imaging light irradiation unit for irradiating the sample with imaging light and an imaging unit for imaging the sample irradiated with the imaging light, analyzing the characteristics of particles contained in the sample based on the image of the sample, comprising: an imaging light irradiation unit for irradiating the sample with imaging light; and an imaging unit for imaging the sample irradiated with the imaging light, the particle analysis program causing a computer to function as an exposure control unit that starts exposure of the imaging unit between the start and end of irradiation of the imaging light by the imaging light irradiation unit, and ends exposure of the imaging unit after the imaging light irradiation unit has ended.

[0024] With this configuration, it is possible to obtain the same effects as those of the particle analyzer described above.

[0025] According to the present invention, particles flowing at high speeds can be clearly imaged.

[0026] 1 is a schematic diagram of a particle analysis device according to an embodiment of the present invention; FIG. 2 is a diagram showing an imaging unit according to the embodiment; FIG. 3 is a diagram showing exposure timing according to the embodiment; FIG. 4 is a flowchart showing a particle analysis method according to the embodiment; FIG. 5 is a schematic diagram showing a particle analysis system according to another embodiment; and FIG. 6 is a diagram showing a constant current circuit according to another embodiment.

[0027] A particle analyzer according to one embodiment of the present invention will be described below with reference to the drawings. Note that in all of the drawings shown below, some parts may be omitted or exaggerated for clarity. The same components are designated by the same reference numerals, and their descriptions will be omitted where appropriate.

[0028] <Device Configuration> The particle analysis device 100 of this embodiment captures an image of a sample in which particles P are dispersed in a dispersion medium, and analyzes the characteristics of the particles P. In this embodiment, the sample is, for example, a pharmaceutical product, food product, and / or a chemical industrial product. Here, the dispersion medium of the sample is a gas, and the particles P contained in the gas are the object of analysis. Note that the particles P may be solid particles or liquid particles.

[0029] 1 , the particle analysis device 100 includes a cell 2 through which a sample flows, an imaging light irradiating unit 3 that irradiates the sample with imaging light, an imaging unit 4 that images the sample irradiated by the imaging light irradiating unit 3, and an information processing device 5 that controls the imaging light irradiating unit 3 and the imaging unit 4 and processes the image captured by the imaging unit 4. The configuration of each unit will be described below.

[0030] The cell 2 is a so-called dry cell in which particles P are dispersed in a gas, and includes an inlet port a1 to which a sample is supplied, an outlet port a2 from which the sample is discharged, and an internal flow path connected to the inlet port a1 and the outlet port a2 and through which the sample flows. The cell 2 is provided on a circulation flow path through which the sample circulates, and in addition to the cell 2, the circulation flow path may be provided with a circulation pump and / or a particle agitator for keeping the particles dispersed in the gas. Here, the speed of the particles P flowing through the internal flow path of the cell 2 is high, for example, 1 μsec or less per unit length.

[0031] The imaging light irradiator 3 irradiates the sample flowing through the internal flow path of the cell 2 with imaging light, which is light for imaging the sample, and is, for example, an LED. The imaging light referred to here includes flash light, which is light with a short irradiation time, for example, of several microseconds or less, and / or light with an irradiation time longer than several microseconds (for example, having an irradiation time of several seconds or more). Note that the imaging light irradiator 3 may include an optical system, such as a collimator or a lens, in addition to a light source, such as an LED.

[0032] In this embodiment, the time from the start of irradiation of the imaging light to the end of irradiation of the imaging light (hereinafter also referred to as irradiation time) is, for example, several microseconds. Here, the start of irradiation of the imaging light refers to the time when the imaging light control unit 51 (described later) outputs a start timing signal, and the end of irradiation of the imaging light refers to the time when the imaging light control unit 51 (described later) outputs an end timing signal.

[0033] The imaging unit 4 is configured to image the sample flowing through the internal flow path of the cell 2 while the sample is irradiated with and exposed to imaging light. Here, the imaging unit 4 is, for example, a CMOS camera.

[0034] In this embodiment, the imaging unit 4 includes a plurality of light-receiving elements 41 that receive imaging light and light from the sample. As shown in Fig. 2, the plurality of light-receiving elements 41 are arranged in a matrix on a single substrate, and are arranged corresponding to pixel rows L1 to Ln obtained by dividing the substrate horizontally into n rows. In addition to the light-receiving elements 41, the imaging unit 4 may also include an optical system such as a lens.

[0035] The state in which the imaging unit 4 is exposed refers to a state in which the light-receiving elements 41 are able to receive light, and specifically refers to the state from the time when the light-receiving elements 41 are able to start accumulating charge due to irradiation with light to the time when readout of the charge accumulated in the light-receiving elements 41 begins. When the imaging unit 4 is exposed, the light-receiving elements 41 receive imaging light, causing charge to accumulate in the light-receiving elements 41. Then, when the exposure state of the imaging unit 4 ends, the charge accumulated in the light-receiving elements 41 is read out in order, starting with the light-receiving elements 41 arranged in pixel row L1. This allows an image to be obtained for each pixel row.

[0036] The information processing device 5 is a general-purpose or dedicated computer equipped with a CPU, memory, input / output interface, etc., and performs at least the functions of an imaging light control unit 51, an exposure control unit 52, and an image analysis unit 53, as shown in FIG. 1, by causing the CPU and peripheral devices to cooperate in accordance with a predetermined program stored in a predetermined area of ​​the memory.

[0037] The imaging light control unit 51 controls the timing at which the imaging light irradiator 3 irradiates the imaging light. Specifically, the imaging light control unit 51 outputs a start timing signal for starting irradiation of the imaging light and an end timing signal for ending irradiation of the imaging light to a drive circuit (not shown) that drives the imaging light irradiator 3. The drive circuit receives the start timing signal and the end timing signal and drives the imaging light irradiator 3 to start and end irradiation of the imaging light, respectively.

[0038] The exposure control unit 52 controls the start and end timings of exposure of the imaging unit 4. Specifically, the exposure control unit 52 starts exposure of the imaging unit 4 between the start and end of irradiation of imaging light by the imaging light irradiator 3, and ends exposure of the imaging unit 4 after the imaging light irradiator 3 has finished irradiating imaging light. In this embodiment, the exposure control unit 52 is an electronic shutter in which the start and end timings of exposure of the imaging unit 4 are preset to predetermined timings. More specifically, the exposure control unit 52 is a rolling shutter that controls the start and end timings of exposure of the multiple light receiving elements 41.

[0039] Specifically, the exposure control unit 52 obtains from the imaging light control unit 51 the time t1 at which the start timing signal is output. Then, as shown in FIG. 3 , the exposure control unit 52 starts the exposure of the multiple light receiving elements 41 at the same time t2 by the time t3 at which the end timing signal is output. Specifically, the exposure control unit 52 turns on the multiple light receiving elements 41 at the same time t2, thereby simultaneously starting the exposure of the multiple light receiving elements 41. As a result, as shown in FIG. 3 , during the period from the time t2 at which the exposure control unit 52 starts the exposure of the multiple light receiving elements 41 to the time t3 at which the end timing signal is output (the hatched portion in FIG. 3 , hereinafter also referred to as the imaging period), the multiple light receiving elements 41 receive light, and electric charge is accumulated in the multiple light receiving elements 41.

[0040] In this embodiment, the timing t2 at which the exposure control unit 52 starts exposing the plurality of light receiving elements 41 is closer to the timing t3 at which the end timing signal is output than to the timing t1 at which the start timing signal is output, and more preferably, is immediately before the timing t3 at which the end timing signal is output. With this configuration, the imaging period is shorter than in the past.

[0041] Here, "immediately before time t3" at which the end timing signal is output refers to the time between time t2 and time t3 being shorter than the time obtained by dividing the particle diameter of particle P and the relative error of particle P by the velocity of particle P, and is, for example, about 100 ns to 500 ns before time t3. Here, when imaging particles P flowing at high speeds, for example, 1 μsec or less per unit length, the particle diameter of particle P used to calculate the time immediately before time t3 is preferably the smallest particle diameter of the particles P to be measured, and the measurement error of particle P is determined based on this smallest particle diameter.

[0042] Then, after the irradiation of the imaging light is completed, the exposure control unit 52 sequentially ends the exposure of the plurality of light receiving elements 41 at mutually different timings. Specifically, after the end timing signal is output, the exposure control unit 52 obtains the time t3 at which the end timing signal was output from the imaging light control unit 51. Then, as shown in FIG. 3 , after the time t3 at which the end timing signal is output, the exposure control unit 52 ends the exposure of the light receiving elements 41 arranged in each pixel row in order, starting with the light receiving elements 41 arranged in pixel row L1. Note that the exposure of the light receiving elements 41 arranged in the same pixel row ends at the same timing.

[0043] The image analysis unit 53 combines the images in each pixel row obtained by the multiple light receiving elements 41 into one image and analyzes the characteristics of the particles P displayed in the combined image. The characteristics of the particles P referred to here are parameters that indicate the shape of the particles P, such as the circle-equivalent diameter, major axis, minor axis, perimeter, aspect ratio, circularity, and / or unevenness of the particles P. The image analysis unit 53 displays the characteristics of the particles P and / or the combined image on a display unit D, such as a display.

[0044] <Particle Analysis Method> Next, a particle analysis method using the particle analysis device 100 of this embodiment will be described with reference to FIG.

[0045] First, a sample is introduced into the cell 2. Then, while the sample is flowing through the cell 2, irradiation with imaging light is started (S1). Specifically, the imaging light control unit 51 outputs a start timing signal, which causes the drive circuit to drive the imaging light irradiation unit 3, and the imaging light irradiation unit 3 irradiates the sample with imaging light.

[0046] 3, during a flash period, which is the period from the start to the end of irradiation of imaging light, the exposure control unit 52 starts exposure of the imaging unit 4 (S2). Specifically, the exposure control unit 52 acquires from the imaging light control unit 51 the time t1 at which the imaging light control unit 51 outputs a start timing signal, and starts exposure of the multiple light receiving elements 41 at the same time t2 until the time t3 at which the imaging light control unit 51 outputs an end timing signal.

[0047] After the exposure control unit 52 starts exposing the plurality of light receiving elements 41, the irradiation of the imaging light ends (S3). Specifically, the imaging light control unit 51 acquires the timing t2 at which the exposure of the plurality of light receiving elements 41 starts from the exposure control unit 52, and outputs an end timing signal after the timing t2. This stops the drive circuit, and the irradiation of the imaging light irradiated from the imaging light irradiating unit 3 ends.

[0048] After the irradiation of the imaging light is completed, the exposure control unit 52 terminates the exposure of the imaging unit 4 (S4). Specifically, the exposure control unit 52 terminates the exposure of the plurality of light receiving elements 41 by sequentially turning off the light receiving elements 41 arranged in each pixel row, starting with the light receiving elements 41 arranged in pixel row L1.

[0049] When the exposure for each pixel row ends, the electric charges accumulated in the pixel row between time t2 when the exposure started and time t3 when the end timing signal is output are read out. An image for each pixel row is obtained based on the read-out electric charges.

[0050] Once the images for each pixel row are obtained, the image analysis unit 53 analyzes the characteristics of the particles P based on the images (S5). Specifically, the image analysis unit 53 synthesizes the images for each pixel row to generate a single image, and analyzes the characteristics of the particles P shown in the synthesized image.

[0051] When the image analysis unit 53 analyzes the characteristics of the particles P, the synthesized image and / or the characteristics of the particles P are output to the display unit D (S6).

[0052] <Effects of the Present Embodiment> According to the particle analysis device 100 of the present embodiment, the exposure control unit 52 starts the exposure of the image capture unit 4 between the start and end of irradiation of the imaging light, and ends the exposure of the image capture unit 4 after the end of irradiation of the imaging light. This prevents the time from the start to the end of irradiation of the imaging light from being shortened, and stabilizes the amount of imaging light. In addition, the time from the start of exposure to the end of irradiation of the imaging light is shorter than in the past, so the irradiation time can be artificially shortened. Therefore, it is possible to obtain artificially fast imaging light using an existing device, and it is possible to clearly image particles flowing at high speeds, for example, with a unit length of several microseconds or less, while stabilizing the amount of imaging light.

[0053] Other Embodiments The present invention is not limited to the above-described embodiments.

[0054] For example, as shown in Fig. 5, a particle analysis system 1000 may further include a particle size distribution measuring device 200 that measures the particle size distribution of particles in addition to the particle analysis device 100 of the above embodiment. Here, the method used to measure the particle size distribution may be any of laser diffraction / scattering, centrifugal sedimentation, particle tracking, and dynamic light scattering. In the following, a particle size distribution measuring device 200 that measures the particle size distribution by laser diffraction / scattering will be used as an example, but is not limited to this.

[0055] Specifically, the particle size distribution measuring device 200 includes a measurement light irradiating unit 210 that irradiates light onto a sample when measuring the particle size distribution of particles, a detector 220 that detects diffracted light and / or scattered light generated from the sample, and a particle size distribution calculating unit 230 that calculates the particle size distribution of particles contained in the sample based on a light intensity signal output from the detector 220.

[0056] The measurement light irradiator 210 is provided separately from the imaging light irradiator 3, and irradiates the sample flowing through the internal flow path of the cell 2 with, for example, laser light. The measurement light irradiator 210 may be, for example, a semiconductor laser. Here, as shown in FIG. 4 , the cell 2 irradiated with the imaging light and the cell 2 irradiated with the laser light are the same. Note that the measurement light irradiator 210 may irradiate the sample with laser light via an optical member such as a lens.

[0057] The detector 220 detects the light intensity of the diffracted light and / or scattered light generated by irradiation with laser light according to the divergence angle, and here, multiple detectors are provided to detect the light intensity of the diffracted light and / or scattered light according to the divergence angle.

[0058] The particle size distribution calculation unit 230 is provided in a general-purpose or dedicated computer equipped with a CPU, memory, input / output interface, etc., and calculates the particle size distribution of particles contained in a sample based on the light intensity signals output from the detectors 220. Specifically, the particle size distribution corresponding to the scattering pattern is calculated based on a scattering pattern indicated by the light intensity signals output from each detector 220, which is composed of the scattering angle and the intensity of the scattered light at that scattering angle, and a theoretical calculation formula such as Mie scattering theory. Particle size distribution data indicating the particle size distribution calculated by the particle size distribution calculation unit 230 is stored in a predetermined memory and displayed on the display unit D. Note that in FIG. 5 , the particle size distribution calculation unit 230 is provided in the same computer as the computer constituting the information processing device 5, which is provided with the imaging light control unit 51, the exposure control unit 52, and the image analysis unit 53, but it may also be provided in a different computer.

[0059] With this configuration, the particle size distribution measurement and the image-based analysis of the characteristics of the particles P can be performed in one particle analysis system 1000.

[0060] As shown in FIG. 6 , the particle analysis device 100 may further include a constant current circuit 6 that supplies a constant current to the imaging light irradiation unit 3 .

[0061] The constant current circuit 6 performs pulse driving on the imaging light irradiator 3, causing the imaging light irradiator 3 to oscillate imaging light in pulses. Specifically, the constant current circuit 6 has a measuring element 61 that measures the current flowing in the imaging light irradiator 3 and outputs a measurement signal, a shunt regulator 62 that outputs a feedback signal based on the measurement signal, and a current control element 63 that controls the current flowing in the imaging light irradiator 3 using the feedback signal.

[0062] The measuring element 61 is for detecting the current flowing through the imaging light emitting unit 3, is connected in series to the imaging light emitting unit 3, and is specifically a resistive element having a predetermined resistance value.

[0063] The shunt regulator 62 has a control terminal connected to the anode side of the measurement element 61 to input a measurement signal, and an output terminal that outputs a feedback signal and is connected to the control terminal of the current control element 63, and is operated with a single power supply.

[0064] The current control element 63 is, for example, a transistor, and causes a current corresponding to a feedback signal input to a control terminal of the shunt regulator 62 to flow through the LED 22 .

[0065] 6, the constant current circuit 6 is further provided with a resistive element 7 having a predetermined resistance value between the output terminal of the shunt regulator 62 and the control terminal of the current control element 63, and a voltage dividing circuit 8 which is provided between the measuring element 61 and the shunt regulator 62 and has at least one resistive element constituted by a variable resistive element 81 whose resistance value is variable. Note that the constant current circuit 6 does not necessarily have to be provided with the resistive element 7 and the voltage dividing circuit 8.

[0066] Alternatively, as another mode for controlling the imaging light irradiator 3 with less jitter, the particle analysis device 100 may further include a switching element (not shown) connected to the constant current circuit 6 to turn on and off the current flowing through the imaging light irradiator 3. Specifically, the switching element is connected in series to the imaging light irradiator 3 or the constant current circuit 6 and switches between an on state and an off state. Examples of the switching element include a MOFSET and a transistor.

[0067] In the above embodiment, the exposure control unit 52 is an electronic shutter, but it may also be a mechanical shutter that is provided on the optical path of light incident on the imaging unit 4 and that physically opens and closes. Even in this case, the irradiation time can be artificially shortened without shortening the time from when the mechanical shutter is opened to when it is closed.

[0068] In the above embodiment, the exposure control unit 52 is a rolling shutter, but it may be a global shutter in which the multiple light receiving elements 41 are exposed at the same time for the same exposure time. In this case, the multiple light receiving elements 41 start receiving light at the same time, so it is easy to generate a period in which all of the multiple light receiving elements 41 are exposed before the irradiation of the imaging light ends. Note that if the exposure control unit 52 is a global shutter, the timing at which the multiple light receiving elements 41 start receiving light may be a point in time before the point in time at which the start timing signal is output.

[0069] In the above embodiment, the exposure control unit 52 is a rolling shutter that starts the exposure of the plurality of light receiving elements 41 at the same timing, but it may be a rolling shutter that starts the exposure of the plurality of light receiving elements 41 at different timings. Even in this case, image distortion can be suppressed by ending the irradiation of the imaging light between the start and end of the exposure of the plurality of light receiving elements 41.

[0070] In the above embodiment, the dispersion medium of the sample is a gas, but the dispersion medium of the sample may be a liquid. In this case, the cell 2 may be a so-called wet cell in which particles P are dispersed in a liquid. Furthermore, in the above embodiment, the cell 2 is a flow cell into which the sample is introduced and discharged, but it may also be a batch-type cell into which the sample is accommodated.

[0071] In the above embodiment, the start of irradiation of imaging light refers to the time when a start timing signal is output, and the end of irradiation of imaging light refers to the time when an end timing signal is output, but the start and end of irradiation of imaging light may also be determined based on the amount of imaging light.

[0072] In this case, the start of irradiation of imaging light may be determined when the amount of imaging light becomes greater than 0 for the first time, and the end of irradiation of imaging light may be determined when the amount of imaging light becomes 0 for the first time after the start of irradiation of imaging light. Note that the amount of imaging light may be calculated based on not only the amount of imaging light itself but also the current flowing through the imaging light irradiator 3.

[0073] In addition, the present invention can be modified in various ways without departing from the spirit of the invention.

[0074] According to the present invention, particles flowing at high speeds can be clearly imaged.

[0075] REFERENCE SIGNS LIST 100 Particle analysis device 2 Cell 3 Imaging light irradiation unit 4 Imaging unit 41 Light receiving element 5 Information processing device 51 Imaging light control unit 52 Exposure control unit 53 Image analysis unit 6 Constant current circuit 7 Switching element

Claims

1. A particle analysis device that analyzes the characteristics of particles contained in a sample based on an image of the sample, comprising: an imaging light irradiation unit that irradiates the sample with imaging light, which is light for imaging the sample; an imaging unit that images the sample irradiated with the imaging light; and an exposure control unit that starts exposure of the imaging unit between the time when the imaging light irradiation unit starts and the time when the imaging light irradiation unit stops irradiating the imaging light, and ends exposure of the imaging unit after the imaging light irradiation unit stops irradiating the imaging light.

2. The particle analysis device according to claim 1, wherein the exposure control unit is an electronic shutter in which the start timing and / or end timing of exposure of the imaging unit is preset to a predetermined timing.

3. A particle analysis device as described in claim 2, wherein the imaging unit has a plurality of light receiving elements, and the exposure control unit is a rolling shutter that sequentially controls the start timing and / or end timing of exposure for the plurality of light receiving elements.

4. A particle analysis device as described in claim 3, wherein the exposure control unit is a rolling shutter that starts exposure of each of the multiple light receiving elements at the same timing and sequentially ends exposure of each of the multiple light receiving elements at different timings.

5. A particle analysis device according to any one of claims 1 to 4, further comprising a constant current circuit for supplying a constant current to said imaging light irradiation unit.

6. The particle analysis device according to claim 5, wherein the constant current circuit performs pulse driving on the imaging light irradiating section, causing the imaging light irradiating section to oscillate the imaging light in pulses.

7. The particle analysis device according to claim 5, further comprising a switching element connected to said constant current circuit for turning on and off the current flowing through said imaging light irradiation unit.

8. A particle analysis device according to any one of claims 1 to 7, further comprising a dry cell through which the sample, whose dispersion medium is a gas, flows or is contained, and the imaging unit images the sample flowing through the dry cell.

9. A particle analysis system for analyzing the characteristics of particles contained in a sample, comprising: a particle analysis device according to any one of claims 1 to 8; and a particle size distribution measurement device for measuring the particle size distribution of particles contained in the sample.

10. A particle analysis method for analyzing the characteristics of particles contained in a sample based on an image of the sample, the method comprising: irradiating the sample with imaging light, which is light for imaging the sample; imaging the sample irradiated with the imaging light; starting exposure between the start and end of irradiation of the imaging light; and ending exposure after the end of irradiation of the imaging light.

11. A particle analysis program used in a particle analyzer comprising an imaging light irradiation unit that irradiates an imaging light, which is light for imaging a sample, onto the sample, and an imaging unit that images the sample irradiated with the imaging light, and that analyzes the characteristics of particles contained in the sample based on the image of the sample, characterized in that the particle analysis program causes a computer to function as an exposure control unit that starts exposure of the imaging unit between the time when the imaging light irradiation unit starts to irradiate the imaging light and the time when the imaging light irradiation unit finishes irradiating the imaging light.

Images