Flow cytometer and position detection method

Abstract

To enable the positional deviation of flow lines to be detected.SOLUTION: A flow cytometer comprises a micro-fluid device, a light source, an optical detector, an information generation device, a computing device, and a spatial light modulation unit. A position detection line for detecting the position of an observation object and a plurality of detection positions for detecting optical information are arranged in a flow path. The plurality of detection positions are arranged in the detection region of the flow path by illumination light, and the position detection line includes a first position detection line and a second position detection line that is located having a section that overlaps the first position detection line in the width direction, the position detection distance of the first and second position detection lines varying depending on the widthwise position. The computing device calculates a position detection distance on the basis of the time difference and flow velocity at which the optical detector detected the intensity peak of an optical signal on the first and second position detection lines, and calculates the widthwise position of the observation object on the basis of a relationship between the position detection distance and the widthwise position or a relationship between a deviation of the time difference from a reference time difference and the widthwise position.SELECTED DRAWING: Figure 20

Description

Technical Field

[0001] The present invention relates to a flow cytometer and a position detection method.

Background Art

[0002] Conventionally, a flow cytometry method for fluorescently staining an object to be observed and evaluating the characteristics of the object to be observed based on the total amount of fluorescence luminance, and a flow cytometer using this flow cytometry method are known (for example, Patent Document 1). In addition, a fluorescence microscope and an imaging cytometer for evaluating microparticles such as cells and bacteria to be observed by an image are known. However, in such measurement methods based on the total amount of fluorescence luminance and scattered light, it has been difficult to capture the characteristics of a measurement target in a two-dimensional space such as the morphological information of cells and the shape of intracellular organelles.

[0003] In a flow cytometer and an imaging cytometer, a flow cytometer and an imaging cytometer have been developed in which an object to be observed is illuminated by illumination light having a predetermined illumination pattern and the object to be observed is detected, and more detailed morphological information of the object to be observed can be obtained. Furthermore, by adopting a random structured illumination pattern as this illumination pattern, it becomes possible to shorten the length of the irradiated illumination pattern, and it becomes possible to speed up the measurement.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the detection of an object to be observed by a random structured illumination pattern is sensitive to the displacement of streamlines. Here, the displacement of streamlines means that the position of the object to be observed flowing with the fluid flowing through the flow path is relatively displaced in the width direction of the flow path with respect to the structured illumination pattern. The width direction of the flow path can be expressed as, for example, a direction perpendicular to both the optical axis of the illumination light irradiated on the flow path and the length direction in which the fluid flows. In the detection by a random structured illumination pattern, it was necessary to ensure the reproducibility of data. On the other hand, since streamlines are affected by pressure fluctuations of the fluid, it is very difficult to precisely control them. Therefore, in a flow cytometer in which an object to be observed is detected by illumination with illumination light having a predetermined illumination pattern, in particular, it is required to monitor the displacement of streamlines in real time and correct the position of the flow path with respect to the displacement of streamlines. Here, the displacement of streamlines that is a problem in the present invention is a displacement of about the pixel size of the structured illumination pattern irradiated on the flow path by the streamlines, and is a displacement of about several micrometers in the width direction of the flow path by the streamlines.

[0006] The present invention has been made in view of the above points, and provides a flow cytometer capable of detecting the displacement of streamlines and a position detection method.

Means for Solving the Problems

[0007] The present invention has been made to solve the above problems. One aspect of the present invention is a microfluidic device including a flow path through which an object to be observed can flow together with a fluid, a light source that irradiates illumination light onto the flow path, a photodetector that detects, in time series, the intensity of a light signal emitted from the object to be observed when the illumination light is irradiated onto the object to be observed flowing through the flow path, an information generation device that generates optical information indicating any one or more of the shape, form, or structure of the object to be observed based on the intensity of the light signal detected by the photodetector, an arithmetic device that calculates the position of the object to be observed in the width direction of the flow path based on the time when the photodetector detects the peak of the intensity of the light signal, and a spatial light modulator that is installed in the optical path between the light source and the photodetector and structures the illumination light. The microfluidic device has, in the flow path, a position detection line that is a collection of a plurality of detection positions for the photodetector to detect the position of the object to be observed, and a plurality of detection positions for the photodetector to detect the optical information. The plurality of detection positions for detecting the optical information are arranged in a detection region of the flow path by the illumination light structured by the spatial light modulator. The position detection line is arranged at a position different from the detection region in the length direction of the flow path, and includes a first position detection line having a length at least in the width direction, and a second position detection line arranged to have a portion overlapping the first position detection line in the width direction. A position detection distance, which is the distance in the length direction of the flow path between the first position detection line and the second position detection line, changes according to the position in the width direction Monotonically changes, The flow velocity of the fluid is constant,The arithmetic unit includes a time difference calculation unit that calculates a time difference between the time when the photodetector detects a peak in the intensity of the optical signal at any of the detection positions on the first position detection line and the time when the photodetector detects a peak in the intensity of the optical signal at any of the detection positions on the second position detection line, a position detection distance calculation unit that calculates the position detection distance based on the time difference calculated by the time difference calculation unit and the flow velocity of the fluid, and a position calculation unit that calculates the position of the observation object in the width direction based on the correspondence relationship between the position detection distance and the position in the width direction, or the deviation between the time difference calculated by the time difference calculation unit and a reference time difference that has been measured in advance as a reference and the correspondence relationship between the position in the width direction. The flow cytometer is provided with these components.

[0008] Also, in one aspect of the present invention, in the flow cytometer described above, the first position detection line and the second position detection line are arranged in the detection region by being subjected to structuring processing by a method different from that of the plurality of detection positions for detecting the optical information.

[0009] Also, in one aspect of the present invention, the flow cytometer described above further includes a flow path position control device that controls the position of the flow path based on the calculation result of the arithmetic unit.

[0011] Also, in one aspect of the present invention, in the flow cytometer described above, the position detection line is a straight line.

[0012] Also, in one aspect of the present invention, in the flow cytometer described above, the angle between the first position detection line and the second position detection line is equal to or greater than a predetermined value.

[0013] Also, in one aspect of the present invention, in the above flow cytometer, in the flow path, a third position detection line which is the position detection line is arranged, and a fourth position detection line which is the position detection line and is substantially parallel to the third position detection line is arranged at a flow velocity measurement distance which is a predetermined distance from the third position detection line and has a portion overlapping the third position detection line in the width direction. The arithmetic unit further includes a flow velocity calculation unit that calculates the flow velocity of the fluid based on the time when the photodetector detects a peak in the intensity of the optical signal at any of the detection positions on the third position detection line, the time when the photodetector detects a peak in the intensity of the optical signal at any of the detection positions on the fourth position detection line, and the flow velocity measurement distance. The position detection distance calculation unit calculates the position detection distance based on the time difference calculated by the time difference calculation unit and the flow velocity calculated by the flow velocity calculation unit.

[0014] Also, in one aspect of the present invention, in the above flow cytometer, the third position detection line and the fourth position detection line are arranged in the detection region by an optical system that does not perform a structuring process in which the illumination light is structured by the spatial light modulation unit.

[0015] Also, in one aspect of the present invention, in the above flow cytometer, any one of the first position detection line and the second position detection line is also served as any one of the third position detection line and the fourth position detection line.

[0016] Also, one aspect of the present invention includes a microfluidic device having a flow path through which an object to be observed can flow together with a fluid, a light source that irradiates the flow path with illumination light, a photodetector that detects, in time series, the intensity of a light signal emitted from the object to be observed when the illumination light is irradiated onto the object to be observed flowing through the flow path, an information generation device that generates optical information indicating any one or more of the shape, form, or structure of the object to be observed based on the intensity of the light signal detected by the photodetector, an arithmetic device that calculates the position of the object to be observed in the width direction of the flow path based on the time when the photodetector detects the peak of the intensity of the light signal, and a spatial light modulator that is installed in the optical path between the light source and the photodetector and structures either the illumination light or the light signal. The microfluidic device has, in the flow path, a position detection line that is a collection of a plurality of detection positions for the photodetector to detect the position of the object to be observed, and a plurality of detection positions for the photodetector to detect the optical information. The plurality of detection positions for detecting the optical information are arranged in a detection region of the flow path by the illumination light structured by the spatial light modulator. The position detection line is arranged at a position different from the detection region in the length direction of the flow path, and includes a first position detection line having a length at least in the width direction, and a second position detection line arranged to have a portion overlapping with the first position detection line in the width direction. A position detection distance, which is the distance in the length direction of the flow path between the first position detection line and the second position detection line, changes monotonically according to the position in the width direction. and changesA method for calculating the position of the object to be observed in the width direction in a flow cytometer, where the flow velocity of the fluid is constant, comprising: a time difference calculation process for calculating the time difference between the time when the optical detector detects the peak of the intensity of the optical signal at any of the detection positions on the first position detection line and the time when the optical detector detects the peak of the intensity of the optical signal at any of the detection positions on the second position detection line; and a position calculation process for calculating the position of the object to be observed in the width direction based on the correspondence between the time difference calculated in the time difference calculation process and the position in the width direction of the position detection distance calculated based on the flow velocity of the fluid, or based on the correspondence between the deviation between the time difference calculated in the time difference calculation process and a reference time difference measured in advance as a reference and the position in the width direction. This is a position detection method in a flow cytometer.

Advantages of the Invention

[0017] According to the present invention, the displacement of the streamline position can be detected.

Brief Description of the Drawings

[0018]

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Mode for Carrying Out the Invention

[0019] (First Embodiment) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing an example of a flow cytometer 1 according to the present embodiment. The flow cytometer 1 includes a microfluidic device 2, a light source 3, a spatial light modulation unit 4, an optical system 5 for light detection, a photodetector 6, a DAQ (Data Acquisition) device 7, a personal computer (PC) 8, and a flow path position control device 9.

[0020] The microfluidic device 2 includes a flow path 20 through which cells C can flow together with a fluid. The flow velocity v of the fluid flowing through the flow path 20 does not depend on the type of cells C flowing through or individual differences. Further, the microfluidic device 2 sequentially flows a plurality of cells through the flow path 20, but the number of cells flowing through the irradiation position of the flow path 20 at one time is 1. The cell C is an example of an object to be observed. Note that the object to be observed is not limited to the cell C, and may be, for example, fine particles or the like as other examples.

[0021] Here, FIG. 1 shows an xyz coordinate system as a three-dimensional orthogonal coordinate system. In the present embodiment, the x-axis direction is the width direction of the flow path 20. Further, the y-axis direction is the length direction of the flow path 20. The z-axis direction is a direction orthogonal to the flow path 20, and is the height or depth direction of the flow path 20. The flow of the fluid in the flow path 20 moves the cell C in the +y direction in the y-axis direction. In other words, the width direction of the flow path 20 is a direction perpendicular to the streamline of the fluid flowing with the cell C.

[0022] The light source 3 and the spatial light modulation unit 4 function as structured illumination. This structured illumination irradiates the flow path 20 with structured illumination light SLE, which is structured illumination light, as described below. The illumination light LE emitted by the light source 3 is irradiated as structured illumination light SLE onto the flow path 20 through the spatial light modulation unit 4. The illumination light LE emitted by the light source 3 may be coherent light or incoherent light. In the present embodiment, as an example, the illumination light LE emitted by the light source 3 is coherent light.

[0023] The spatial light modulation unit 4 is disposed on the optical path between the light source 3 and the photodetector 6. In the present embodiment, the spatial light modulation unit 4 is disposed on the optical path of the illumination light LE irradiated from the light source 3 onto the flow path 20. This configuration of the arrangement is also described as the configuration of structured illumination. Structured illumination irradiates the flow path 20 with the structured illumination light SLE, which is the illumination light LE structured by the spatial light modulation unit 4. Here, structured illumination forms an image of the structured illumination light SLE as a structure illumination pattern 21 in the flow path 20. Details of the structure illumination pattern 21 will be described later.

[0024] Here, referring to FIG. 2, the spatial light modulation unit 4 will be described. FIG. 2 is a diagram showing an example of the spatial light modulation unit 4 according to the present embodiment. The spatial light modulation unit 4 includes a spatial light modulator 40, a first lens 41, a spatial filter 42, a second lens 43, and an objective lens 44. The spatial light modulation unit 4, the spatial light modulator 40, the first lens 41, the spatial filter 42, the second lens 43, and the objective lens 44 are disposed on the optical path between the light source 3 and the photodetector 6 in this order from the side closer to the light source 3.

[0025] The spatial light modulator 40 structures the incident light. Structuring the incident light means modulating the optical characteristics of the incident light for each of a plurality of regions included in the incident surface of the incident light. The spatial light modulator 40 is an optical element that changes the spatial distribution of the incident light according to the calculated fine structure and modulates the optical characteristics of the incident light. The spatial light modulator 40 enables controlling the pattern of light irradiation to irradiate light. The surface of the spatial light modulator 40 where light is incident has a plurality of regions, and the optical characteristics of the illumination light LE are individually modulated in each of the plurality of regions through which it passes. That is, in the light transmitted through the spatial light modulator 40, the optical characteristics of the transmitted light are changed so as to be different from each other in a plurality of regions with respect to the optical characteristics of the incident light. Here, the optical characteristics are, for example, the characteristics of light related to any one or more of intensity, wavelength, phase, and polarization state. Note that the optical characteristics are not limited to these. The spatial light modulator 40 includes, for example, a diffractive optical element (DOE), a spatial light modulator (SLM), and a digital micromirror device (DMD). When the illumination light LE emitted by the light source 3 is incoherent light, the spatial light modulator 40 is a DMD. Micromirror Device).

[0026] In the following description, the position where the structured illumination light SLE in the flow path 20 is irradiated is also referred to as the irradiation position. In the present embodiment, the irradiation position corresponds to the region that transmits light among the plurality of regions of the spatial light modulator 40. In the following description, the region that transmits light of the spatial light modulation unit 4 is referred to as a light transmission region. The shape and size of this light transmission region are the same as those of the light transmission region of the spatial light modulator 40. As an example, the shape of the light transmission region is a square. This square has a side of equal length in the light transmission region of the spatial light modulator 40. The cells C that pass through the irradiation position emit light when the fluorescent molecules are excited by the structured illumination light SLE. The fluorescence due to this emission is an example of the optical signal LS. The optical signal LS includes the transmitted light of the structured illumination light SLE that has passed through the cells C, the scattered light of the structured illumination light SLE scattered by the cells C, and the interference light between the structured illumination light SLE and other light. Note that the shape and size of the light transmission region are not limited to a square as long as they are unified within the light transmission region of the spatial light modulator 40, and the size can also be freely changed. The shape of the light transmission region may be other polygons, a circle, or the like.

[0027] The first lens 41 condenses the structured illumination light SLE that has passed through the spatial light modulator 40 onto the spatial filter 42. The spatial filter 42 makes the intensity distribution of the structured illumination light SLE approach a Gaussian distribution by removing components corresponding to spatially varying noise from the structured illumination light SLE condensed by the first lens 41. The second lens 43 collimates the structured illumination light SLE from which noise has been removed by the spatial filter 42. The objective lens 44 condenses the structured illumination light SLE collimated by the second lens 43 and forms an image at the irradiation position of the flow path 20. Note that the objective lens 44 may be a dry objective lens or an immersion objective lens. The immersion objective lens is, for example, an oil immersion lens or a water immersion lens.

[0028] Returning to FIG. 1, the description of the configuration of the flow cytometer 1 will be continued. The optical system 5 for light detection is an optical mechanism for forming an image of the cell C on the photodetector 6 and includes an imaging lens in its configuration. The optical system 5 for light detection condenses the light signal LS from the cell C with the imaging lens and detects it with the photodetector 6. The light signal LS from the cell C is, for example, fluorescence, transmitted light, scattered light, or interference light. The imaging lens included in the optical system 5 for light detection is preferably arranged at a position where the light signal LS is imaged on the photodetector 6, but may be arranged at a position where a sufficient amount of light is condensed on the photodetector 6. Note that the optical system 5 for light detection may include a dichroic mirror or a wavelength-selective filter in addition to the imaging lens.

[0029] The photodetector 6 condenses and detects the optical signal LS emitted by the cell C by means of the optical system 5 for optical detection. Here, the photodetector 6 detects the optical signal and converts it into an electrical signal. The photodetector 6 is, as an example, a photomultiplier tube (PMT). The photodetector 6 detects the optical signal in time series. The photodetector 6 may be a single sensor or a multi-sensor.

[0030] The DAQ device 7 converts the electrical signal pulses output by the photodetector 6 into electronic data for each pulse. The electronic data includes a pair of time and the intensity of the electrical signal pulse. The DAQ device 7 is, as an example, an oscilloscope.

[0031] The PC 8 includes an information generation unit 80 and an arithmetic unit 81. Based on the electronic data output from the DAQ device 7, the information generation unit 80 generates optical information indicating the morphological information of the cell C. The morphological information of the cell C is any one or more of the shape, form, or structure of the cell C. The information generation unit 80 stores the generated optical information. The optical information is, as an example, information indicating the time-series change in the intensity of the optical signal LS from the cell C by means of a waveform. This waveform corresponds to the morphological information of the cell C, and the optical information can be used to identify the cell C. As another example, the optical information is also used as teacher data when learning the relationship between the morphological information of the cell C and the waveform signal in machine learning, and the cell C is identified from the waveform signal measured at the time of inference using the inference model obtained by supervised learning.

[0032] Based on the time change in the intensity of the optical signal LS detected by the photodetector 6, the arithmetic unit 81 calculates the position x in the width direction of the flow path 20 of the cell C. The details of the configuration and arithmetic processing of the arithmetic unit 81 will be described later. In the following description, calculating the position x in the width direction of the flow path 20 of the cell C based on the time change in the intensity of the optical signal LS detected by the photodetector 6 is also referred to as measuring the position x.

[0033] The information generation unit 80 is an example of an information generation device that generates optical information indicating one or more of the shape, form, or structure of an object to be observed based on the temporal change in the intensity of the optical signal detected by the photodetector. The calculation unit 81 is an example of a calculation device that measures the position x of the object to be observed based on the temporal change in the intensity of the optical signal detected by the photodetector. In this embodiment, an example in which the information generation device and the calculation device are integrated as the PC 8 will be described, but the present invention is not limited to this. The information generation device and the calculation device may be provided as separate devices (for example, a PC).

[0034] The flow path position control device 9 controls the position of the flow path 20 based on the calculation result of the calculation unit 81 of the PC 8. When the calculation result indicates that the position x in the width direction of the flow path 20 of the cell C is deviated from the reference position, the flow path position control device 9 moves the position of the flow path 20 so that this position x coincides with the reference position. Here, as an example, the reference position is the streamline center at the start of measurement. The streamline center at the start of measurement is determined by previously measuring the position in the width direction of the flow path 20 at the center of the path of the cell C at the start of measurement.

[0035] The flow path position control device 9 moves the position of the flow path 20 to a more suitable position for measurement by controlling the position of the automatic stage 100 on which the flow path 20 is placed. The automatic stage 100 is, for example, a piezo stage. The flow path position control device 9 controls the automatic stage 100, which is a piezo stage, via a piezo actuator (not shown).

[0036] Next, referring to FIG. 3, the position detection line L disposed in the flow path 20 will be described. In the present embodiment, the position detection line L is included in the structured illumination pattern 21 shown in FIG. 1 and is disposed in the flow path 20. FIG. 3 is a diagram showing an example of the position detection line L according to the present embodiment. In FIG. 3, the flow path 20 is shown as viewed in the -z direction in the z-axis direction. In the following description, the flow path 20 viewed from the +z direction to the -z direction in the z-axis direction may be simply referred to as the flow path 20 viewed from the z-axis direction, etc. In the flow path 20, as the position detection lines L, a first position detection line L1, a second position detection line L2, a third position detection line L3, and a fourth position detection line L4 are arranged.

[0037] The position detection line L is a collection of a plurality of detection positions for the photodetector 6 to measure the position x of the cell C. When the cell C passes through the detection position of the flow path, the optical signal LS emitted from the cell C is detected by the photodetector 6. That is, the detection position is the position where the photodetector 6 detects the intensity of the optical signal LS. The detection positions included in the position detection line L are used by the arithmetic unit 81 to calculate the position x of the cell C in the width direction of the flow path 20. The position detection line L has a length at least in the width direction of the flow path 20. Having a length in the width direction of the flow path 20 means having a length when projected in the width direction, that is, the x-axis direction. In the present embodiment, as shown in FIG. 3, the position detection line L is a straight line.

[0038] Further, the flow path 20 has a detection region R. The detection region R is a region where a plurality of detection positions for the photodetector 6 to detect optical information regarding the morphological information of the cell C are randomly arranged. A structured illumination pattern randomly arranged at the irradiation position of the flow path 20 is irradiated, and when the cell C passes through the position of the detection region R of the flow path, the optical signal LS emitted is detected by the photodetector 6 to obtain optical information regarding the morphological information of the cell C. That is, the plurality of detection positions arranged in the detection region R are used for the detection of the cell C by the information generation unit 80 to generate optical information indicating the morphology of the cell C. The information generation unit 80 generates optical information based on the random pattern of the arrangement of the detection positions arranged in the detection region R.

[0039] The detection position corresponds to the irradiation position where the above-described structured illumination light SLS is irradiated in the flow path 20 as viewed from the z-axis direction. As described above, the irradiation position corresponds to the light transmission region in the spatial light modulator 40 which is a spatial filter.

[0040] The first position detection line L1 and the second position detection line L2 are used to measure the position x in the width direction of the flow path 20 of the cell C. On the other hand, the third position detection line L3 and the fourth position detection line L4 are used to measure the flow velocity v of the fluid flowing through the flow path 20. Taking the arrangement in FIG. 3 below as an example, the arrangement of the first position detection line L1, the second position detection line L2, the third position detection line L3, and the fourth position detection line L4 in the flow path 20 will be further described.

[0041] The first position detection line L1 and the second position detection line L2 are arranged on the upstream side (-y direction in the y-axis direction) of the flow path 20 from the detection region R. The second position detection line L2 is arranged on the downstream side (+y direction in the y-axis direction) of the flow path 20 from the first position detection line L1.

[0042] The third position detection line L3 and the fourth position detection line L4 are arranged on the downstream side (+y direction in the y-axis direction) of the flow path 20 from the first position detection line L1 and the second position detection line L2. The third position detection line L3 is arranged on the upstream side (-y direction in the y-axis direction) of the flow path 20 from the detection region R. The fourth position detection line L4 is arranged on the downstream side (+y direction in the y-axis direction) of the flow path 20 from the third position detection line L3 across the detection region R.

[0043] The first position detection line L1 is arranged at a predetermined angle with respect to the width direction (x-axis direction) of the flow path 20. Here, the predetermined angle is, for example, 45 degrees. The second position detection line L2 is arranged parallel to the width direction (x-axis direction) of the flow path 20.

[0044] Here, the second position detection line L2 is arranged to have a portion overlapping the first position detection line L1 in the width direction of the flow path 20. That the second position detection line L2 has a portion overlapping the first position detection line L1 in the width direction of the flow path 20 means that the line segment obtained by projecting the first position detection line L1 in the x-axis direction and the line segment obtained by projecting the second position detection line L2 in the x-axis direction have a portion overlapping each other.

[0045] In addition, the distance in the length direction of the flow path 20 between the first position detection line L1 and the second position detection line L2 changes according to the position in the width direction of the flow path 20. The distance in the length direction of the flow path 20 between the first position detection line L1 and the second position detection line L2 and the position in the width direction of the flow path 20 correspond one-to-one. In the following description, the distance in the length direction of the flow path 20 between the first position detection line L1 and the second position detection line L2 may be referred to as the position detection distance D12.

[0046] The first position detection line L1 and the second position detection line L2 are arranged such that the position detection distance D12 changes monotonically with respect to the x-axis. In FIG. 3, as an example, as the value of the coordinate on the x-axis changes from 0 micrometers to 50 micrometers, the position detection distance D12 monotonically decreases from 50 micrometers to 0 micrometers. Note that the first position detection line L1 and the second position detection line L2 may be arranged such that the position detection distance D12 increases monotonically with respect to the x-axis.

[0047] As described above, the position detection distance D12 and the position in the width direction of the flow path 20 correspond one-to-one. In the flow cytometer 1, the position x in the width direction of the flow path 20 of the cell C is calculated based on the correspondence between the position detection distance D12 and the position in the width direction of the flow path 20. Here, the time difference between the time t1 when the photodetector 6 detects the peak of the optical signal intensity at any detection position on the first position detection line L1 and the time t2 when the photodetector 6 detects the peak of the optical signal intensity at any detection position on the second position detection line L2 is referred to as the time difference τ. In the flow cytometer 1, the position detection distance D12 corresponding to the position x is calculated based on the time difference τ and the flow velocity v of the fluid flowing through the flow path 20. Note that detecting the optical signal LS emitted by the cell C passing through the detection position with the photodetector 6 and detecting the passage of the cell C as the waveform of the optical signal are herein expressed as detecting the peak of the optical signal at the detection position. In the following description, the case where the passage of the cell C is detected by the peak of the optical signal will be described as an example, but it can also be detected by other positions where the waveform rises or the intensity of the optical signal shows a value equal to or higher than a predetermined threshold. In this embodiment, as an example, when the position x in the width direction of the flow path 20 of the cell C is shifted in the +x direction of the x-axis, the time difference τ monotonically increases according to this shift.

[0048] The third position detection line L3 is arranged parallel to the width direction (x-axis direction) of the flow path 20. The fourth position detection line L4 is substantially parallel to the third position detection line L3 and is arranged at a predetermined distance from the third position detection line L3. The fourth position detection line L4 is arranged so as to have a portion overlapping with the third position detection line L3 in the width direction of the flow path 20. In the following description, the distance between the third position detection line L3 and the fourth position detection line L4 is referred to as the flow velocity measurement distance D34.

[0049] Here, the time difference between the time t3 when the photodetector 6 detects the peak of the intensity of the optical signal at any detection position on the third position detection line L3 and the time t4 when the photodetector 6 detects the peak of the intensity of the optical signal at any detection position on the fourth position detection line L4 is referred to as the time difference dt34. In the flow cytometer 1, the flow velocity v is measured based on the time difference dt34 and the flow velocity measurement distance D34.

[0050] The description of the arrangement of the first position detection line L1, the second position detection line L2, the third position detection line L3, and the fourth position detection line L4 above is made along the description of FIG. 3, but the arrangement of the position detection line L is not limited to this. For example, the first position detection line L1 and the second position detection line L2 may be arranged on the downstream side (+y direction in the y-axis direction) of the flow path 20 from the detection region R. The second position detection line L2 may be arranged on the upstream side (-y direction in the y-axis direction) of the flow path 20 from the first position detection line L1.

[0051] Further, if the fourth position detection line L4 is on the downstream side (+y direction in the y-axis direction) of the flow path 20 from the third position detection line L3, it may be arranged on the upstream side (-y direction in the y-axis direction) from the detection region R. That is, both the third position detection line L3 and the fourth position detection line L4 may be arranged on the upstream side (-y direction in the y-axis direction) from the detection region R. Also, both the third position detection line L3 and the fourth position detection line L4 may be arranged on the downstream side (+y direction in the y-axis direction) from the detection region R.

[0052] Furthermore, the third position detection line L3 may be disposed on the upstream side (the -y direction in the y-axis direction) of the first position detection line L1. Also, both the third position detection line L3 and the fourth position detection line L4 may be disposed on the upstream side (the -y direction in the y-axis direction) of the first position detection line L1. Furthermore, both the third position detection line L3 and the fourth position detection line L4 may be disposed at a position between the first position detection line L1 and the second position detection line L2, and either one of the third position detection line L3 and the fourth position detection line L4 may be disposed at a position between the first position detection line L1 and the second position detection line L2. For example, they may be provided in the order of the third position detection line L3, the first position detection line L1, the second position detection line L2, and the fourth position detection line L4 from the upstream side, or may be provided in the order of the first position detection line L1, the third position detection line L3, the second position detection line L2, and the fourth position detection line L4 from the upstream side, or may be provided in the order of the first position detection line L1, the third position detection line L3, the fourth position detection line L4, and the second position detection line L2 from the upstream side.

[0053] Note that in order to improve the accuracy of the measurement of the flow velocity v, it is preferable that the flow velocity measurement distance D34 is long. That is, the third position detection line L3 and the fourth position detection line L4 are preferably arranged so as to increase the flow velocity measurement distance D34.

[0054] In the present embodiment, the position detection line L is arranged without a gap in the width direction of the flow path 20. That is, the length of the position detection line L in the width direction of the flow path 20 is equal to the width of the flow path 20. Also, in the present embodiment, the two position detection lines L (the first position detection line L1 and the second position detection line L2) for measuring the position x of the cell C in the width direction of the flow path 20 are in contact with each other at one end. That is, the position detection distance D12 is zero at one end. Note that, as shown in the example of FIG. 16 described later, the position detection distance D12 does not have to be zero at one end. That is, the first position detection line L1 and the second position detection line L2 do not have to be in contact at either end. Further, as long as the position detection distance D12 monotonically changes with respect to the x-axis, it does not have to be zero at one end of the first position detection line L1 and the second position detection line L2. That is, the first position detection line L1 and the second position detection line L2 may have an intersection other than one end.

[0055] Next, referring to FIGS. 4 and 5, the configuration of the arithmetic unit 81 and the details of the position calculation process will be described. FIG. 4 is a diagram showing an example of the configuration of the arithmetic unit 81 according to the present embodiment. The arithmetic unit 81 includes a control unit 810 and a storage unit 817.

[0056] The control unit 810 includes, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an FPGA (field-programmable gate array), etc., and performs various operations and exchanges of information. The control unit 810 includes a signal intensity acquisition unit 811, a time difference calculation unit 812, a flow velocity calculation unit 813, a position detection distance calculation unit 814, a position calculation unit 815, and an output unit 816. The signal intensity acquisition unit 811, the time difference calculation unit 812, the flow velocity calculation unit 813, the position detection distance calculation unit 814, the position calculation unit 815, and the output unit 816 are each modules realized, for example, by the CPU reading a program from a ROM (Read Only Memory) and executing processing.

[0057] The signal intensity acquisition unit 811 acquires the electronic data SD output from the DAQ device 7. The electronic data SD is electronic data showing the signal intensity of the optical signal LS detected by the photodetector 6 at each time. In the following description, acquiring the electronic data SD is also described as acquiring a signal. Further, the electronic data showing the time change of the signal intensity of the optical signal LS as a waveform is described as a measurement signal SG.

[0058] Based on the electronic data SD acquired by the signal intensity acquisition unit 811, the time difference calculation unit 812 calculates the time difference τ between the time t1 when the passage of the cell C is detected as the peak of the intensity of the optical signal LS at any detection position on the first position detection line L1 and the time t2 when the photodetector 6 detects the passage of the cell as the peak of the intensity of the optical signal at any detection position on the second position detection line L2.

[0059] Based on the electronic data SD acquired by the signal intensity acquisition unit 811, the flow velocity calculation unit 813 calculates the flow velocity v based on the time difference dt34 between the time t3 when the photodetector 6 detects the passage of the cell C as the peak of the intensity of the optical signal LS at any detection position on the third position detection line L3 and the time t4 when the photodetector 6 detects the peak of the intensity of the optical signal at any detection position on the fourth position detection line L4, and the flow velocity measurement distance information 819. The flow velocity measurement distance information 819 is information indicating the flow velocity measurement distance D34.

[0060] Based on the time difference τ calculated by the time difference calculation unit 812 and the flow velocity v calculated by the flow velocity calculation unit 813, the position detection distance calculation unit 814 calculates the position detection distance D12 corresponding to the position x. Based on the position detection distance D12 corresponding to the position x calculated by the position detection distance calculation unit 814 and the detection distance width direction correspondence information 818, the position calculation unit 815 calculates the position x in the width direction of the flow path 20 of the cell C. Here, the detection distance width direction correspondence information 818 is information indicating the correspondence relationship between the position detection distance D12 and the position x in the width direction of the flow path 20. The output unit 816 outputs the position x in the width direction of the flow path 20 of the cell C calculated by the position calculation unit 815 to the flow path position control device 9.

[0061] The memory unit 817 stores the detection distance width direction correspondence information 818 and the flow velocity measurement distance information 819. The detection distance width direction correspondence information 818 is, for example, two-dimensional table-form data consisting of rows and columns in which the values of the positions in the width direction of the flow path 20 are stored for each position detection distance. The detection distance width direction correspondence information 818 is generated in advance based on the arrangement of the first position detection line L1 and the second position detection line L2 in the flow path 20. The flow velocity measurement distance information 819 is generated in advance based on the arrangement of the third position detection line L3 and the fourth position detection line L4 in the flow path 20.

[0062] FIG. 5 is a diagram showing an example of the position calculation process according to the present embodiment. The position calculation process is a process in which the calculation unit 81 calculates the position x in the width direction of the flow path 20 of the cell C. Step S10: The signal intensity acquisition unit 811 acquires the electronic data SD output from the DAQ device 7 as a measurement signal SG that shows the time change of the signal intensity as a waveform.

[0063] Here, referring to FIG. 6, the measurement signal SG will be described. FIG. 6 is an example of the measurement signal SG according to the present embodiment. The measurement signal SG is electronic data showing the time change of the signal intensity of the optical signal LS detected by the photodetector 6 as a waveform.

[0064] The first peak P1 at time t1 corresponds to the optical signal detected when the cell C passes through the first position detection line L1. The second peak P2 at time t2 corresponds to the optical signal detected when the cell C passes through the second position detection line L2. The third peak P3 at time t3 corresponds to the optical signal detected when the cell C passes through the third position detection line L3. The fourth peak P4 at time t4 corresponds to the optical signal detected when the cell C passes through the fourth position detection line L4. Also, the signal PR corresponds to the optical signal detected when the cell C passes through a plurality of detection positions randomly arranged in the detection region R.

[0065] Step S20: The time difference calculation unit 812 calculates the time difference τ between the time t1 when the passage of the cell C is detected as the peak of the intensity of the optical signal at any detection position on the first position detection line L1 and the time t2 when the photodetector 6 detects the passage of the cell as the peak of the intensity of the optical signal at any detection position on the second position detection line L2, based on the electronic data SD acquired by the signal intensity acquisition unit 811. Here, the time difference calculation unit 812 reads the time corresponding to the first peak P1 as the time t1 from the measurement signal SG indicated by the electronic data SD, reads the time corresponding to the second peak P2 as the time t2, and calculates the time difference τ from the read times t1 and t2.

[0066] Step S30: The flow velocity calculation unit 813 calculates the flow velocity v of the fluid flowing through the flow path 20. Here, the flow velocity calculation unit 813 calculates the time difference dt34 between the time t3 when the photodetector 6 detects the peak of the intensity of the optical signal due to the passage of the cell at any detection position on the third position detection line L3 and the time t4 when the photodetector 6 detects the peak of the intensity of the optical signal of the passage of the cell at any detection position on the fourth position detection line L4, based on the electronic data SD acquired by the signal intensity acquisition unit 811, and calculates the flow velocity v based on the time difference dt34 and the flow velocity measurement distance D34. The flow velocity calculation unit 813 reads the time corresponding to the third peak P3 as the time t3 from the measurement signal SG indicated by the electronic data SD, reads the time corresponding to the fourth peak P4 as the time t4, and calculates the time difference dt34 between the read times t3 and t3. The flow velocity calculation unit 813 calculates the flow velocity v by dividing the flow velocity measurement distance D34 indicated by the flow velocity measurement distance information 819 by the calculated time difference dt34.

[0067] Step S40: The position detection distance calculation unit 814 calculates the position detection distance D12 corresponding to the position x in the width direction of the flow path 20 of the cell C, based on the time difference τ calculated by the time difference calculation unit 812 and the flow velocity v calculated by the flow velocity calculation unit 813. Here, the time difference calculation unit 812 calculates the position detection distance D12 corresponding to the position x by dividing the time difference τ by the flow velocity v.

[0068] Step S50: The position calculation unit 815 calculates the position x in the width direction of the flow path 20 of the cell C based on the position detection distance D12 calculated by the position detection distance calculation unit 814 and the detection distance width direction correspondence information 818. As described above, the position detection distance D12 is calculated based on the time difference τ calculated by the time difference calculation unit 812 and the flow velocity v. That is, the position detection distance D12 is a quantity calculated based on the time difference τ. Therefore, the position calculation unit 815 calculates the position x in the width direction of the flow path 20 of the cell C based on the time difference τ calculated by the time difference calculation unit 812 and the detection distance width direction correspondence information 818.

[0069] Step S60: The output unit 816 outputs the position x in the width direction of the flow path 20 of the cell C calculated by the position calculation unit 815 to the flow path position control device 9. Thus, the arithmetic unit 81 ends the position calculation process.

[0070] In this embodiment, an example in which the flow velocity v is measured using the position detection lines L (the third position detection line L3 and the fourth position detection line L4) for measuring the flow velocity v of the fluid flowing in the flow path 20 has been described, but it is not limited to this. Instead of measuring the flow velocity v, the arithmetic unit 81 may acquire the value of the flow velocity v from the outside and perform the position calculation process.

[0071] When the arithmetic unit 81 acquires the value of the flow velocity v from the outside and performs the position calculation process, the position detection line L for measuring the flow velocity v may not be arranged in the flow path 20. Also, in that case, the arithmetic unit 81 includes a flow velocity acquisition unit instead of the flow velocity calculation unit 813. This flow velocity acquisition unit acquires the value of the flow velocity v from, for example, the microfluidic device 2. Instead of step S30 in the position calculation process of FIG. 5, a process in which the flow velocity acquisition unit acquires the value of the flow velocity v from the microfluidic device 2 is performed. Also, in step S40, the position detection distance calculation unit 814 calculates the position detection distance D12 corresponding to the position x in the width direction of the flow path 20 of the cell C based on the time difference τ calculated by the time difference calculation unit 812 and the flow velocity v acquired by the flow velocity acquisition unit.

[0072] (Modification 1) In the above-described embodiment, an example has been described in the case where the position detection line L used to measure the position x in the width direction of the flow path 20 of the cell C and the position detection line L used to measure the flow velocity v of the fluid flowing through the flow path 20 are separately arranged, but the present invention is not limited to this. In the first modification example, an example in the case where any one of the position detection lines L used to measure the position x in the width direction of the flow path 20 of the cell C and any one of the position detection lines L used to measure the flow velocity v of the fluid flowing through the flow path 20 are combined by one position detection line L will be described.

[0073] FIG. 7 is a diagram showing an example of the position detection line La according to the first modification example. In the flow path 20a, as the position detection line La, a first position detection line L1a, a second position detection line L2a, and a fourth position detection line L4a are arranged. The first position detection line L1a and the second position detection line L2a are position detection lines La for measuring the position x. Here, the second position detection line L2a is a position detection line La for measuring the position x and is also a position detection line La used for measuring the flow velocity v. That is, in the flow path 20a, the third position detection line L3 is combined by the second position detection line L2a. The fourth position detection line L4a is a position detection line La used for measuring the flow velocity v.

[0074] FIG. 8 is a diagram showing an example of the measurement signal SGa according to the first modification example. The first peak P1 at time t1 corresponds to the optical signal detected when the cell C passes through the first position detection line L1a. The second peak P2 at time t2 corresponds to the optical signal detected when the cell C passes through the second position detection line L2a. The fourth peak P4 at time t4 corresponds to the optical signal detected when the cell C passes through the fourth position detection line L4a.

[0075] The flow velocity calculation unit 813, in calculating the flow velocity v in step S30 described above, reads from the measurement signal SGa the time corresponding to the second peak P2 as time t2, reads the time corresponding to the fourth peak P4 as time t4, and calculates the time difference dt34 between the read time t2 and time t4. In the first modification example 1, since the third position detection line L3 is also served by the second position detection line L2a, the time t3 corresponding to the third peak P3 is also served by the time t2 corresponding to the second peak.

[0076] (Modification Example 2) In the above-described embodiment, in the flow path 20, an example in which two position detection lines L (the first position detection line L1 and the second position detection line L2) are arranged to measure the position x in the width direction of the flow path 20 of the cell C, and the position x is measured once when one cell C passes through the flow path 20 has been described. However, the present invention is not limited to this. The position x in the width direction of the flow path 20 of the cell C may be measured multiple times when one cell C passes through the flow path 20. In the second modification example, an example in which three or more position detection lines L for measuring the position x are arranged will be described.

[0077] FIG. 9 is a diagram showing an example of the position detection line Lb according to the second modification example. In the flow path 20b, as the position detection line Lb, a first position detection line L1b, a second position detection line L2b, a fourth position detection line L4b, and a fifth position detection line L5b are arranged. In the flow path 20b, the first position detection line L1b, the second position detection line L2b, the fourth position detection line L4b, and the fifth position detection line L5b are position detection lines Lb for measuring the position x. That is, four position detection lines L for measuring the position x are arranged in the flow path 20b.

[0078] In the second modification example, the first measurement of the position x is performed using the first position detection line L1b and the second position detection line L2b. After the cell C passes through the detection region R, the second measurement of the position x is performed using the fourth position detection line L4b and the fifth position detection line L5b. The position x1, which is the position x measured for the first time, and the position x2, which is the position x measured for the second time, are used, for example, to measure the inclination of the streamline.

[0079] The second position detection line L2b and the fourth position detection line L4b are position detection lines Lb for measuring the position x and are also position detection lines Lb used for measuring the flow velocity v. That is, in the flow path 20b, similar to the above-described Modification 1, the third position detection line L3 used for measuring the flow velocity v is also served by the second position detection line L2a for measuring the position x. Further, the fourth position detection line L4b used for measuring the flow velocity v is also served by the position detection line used for the second measurement of the position x.

[0080] FIG. 10 is a diagram showing an example of the measurement signal SGb according to this Modification 2. The first peak P1 at time t1 corresponds to the optical signal detected when the cell C passes through the first position detection line L1b. The second peak P2 at time t2 corresponds to the optical signal detected when the cell C passes through the second position detection line L2b. The third peak P3 at time t3 corresponds to the optical signal detected when the cell C passes through the fourth position detection line L4b. The fourth peak P4 at time t4 corresponds to the optical signal detected when the cell C passes through the fifth position detection line L5b.

[0081] In the calculation of the flow velocity v in step S20 described above, the time difference calculation unit 812 reads the time corresponding to the first peak P1 from the measurement signal SGb as time t1, reads the time corresponding to the second peak P2 as time t2, and calculates the difference between the read time t1 and time t2 as the time difference τ1. Further, the time difference calculation unit 812 reads the time corresponding to the third peak P3 as time t1, reads the time corresponding to the fourth peak P4 as time t2, and calculates the difference between the read time t1 and time t2 as the time difference τ2.

[0082] In step S40, the position detection distance calculation unit 814 calculates a position detection distance D12-1 corresponding to the position x1 in the width direction of the flow path 20 of the cell C based on the time difference τ1 calculated by the time difference calculation unit 812 and the flow velocity v calculated by the flow velocity calculation unit 813. Further, the position detection distance calculation unit 814 calculates a position detection distance D12-2 corresponding to the position x2 in the width direction of the flow path 20 of the cell C based on the time difference τ2 calculated by the time difference calculation unit 812 and the flow velocity v calculated by the flow velocity calculation unit 813.

[0083] In step S50, the position calculation unit 815 calculates the positions x1 and x2 in the width direction of the flow path 20 of the cell C based on the position detection distances D12-1 and D12-2 calculated by the position detection distance calculation unit 814 and the detection distance width direction correspondence information 818. The position calculation unit 815 calculates the inclination of the streamline of the fluid flowing through the flow path 20 based on the calculated positions x1 and x2. The position calculation unit 815 may correct the position x based on the calculated inclination of the streamline.

[0084] Note that the position detection distance calculation unit 814 may calculate the average of the position detection distance D12-1 calculated based on the time difference τ1 and the position detection distance D12-2 calculated based on the time difference τ2 as the position detection distance D12. Also, in step S20, the time difference calculation unit 812 may calculate the average of the time difference τ1 and the time difference τ2 as the time difference τ.

[0085] (Modification Example 3) In the above-described embodiment and its modification example, an example in which the angle between the two position detection lines L for measuring the position x in the width direction of the flow path 20 of the cell C in the flow path 20 is 45 degrees has been described, but it is not limited thereto. In this modification example 3, an example in which the angle between the first position detection line L1c and the second position detection line L2c is 45 degrees or more will be described.

[0086] FIG. 11 is a diagram showing an example of the position detection line Lc according to the third modified example. In the flow path 20c, as the position detection line Lc, a first position detection line L1c, a second position detection line L2c, a third position detection line L3c, and a fourth position detection line L4c are arranged. In the flow path 20c, the first position detection line L1c and the second position detection line L2c are position detection lines Lc for measuring the position x. Here, the second position detection line L2c is a position detection line Lc for measuring the position x and is also a position detection line Lc used for measuring the flow velocity v. That is, in the flow path 20c, the third position detection line L3c is also served by the second position detection line L2c. The fourth position detection line L4c is a position detection line Lc used for measuring the flow velocity v.

[0087] Here, the angle between the first position detection line L1c and the second position detection line L2c is set to be a predetermined angle (for example, 45 degrees) or more. In the example of FIG. 11, the angle between the first position detection line L1c and the second position detection line L2c is 90 degrees. The fourth position detection line L4c is arranged substantially parallel to the second position detection line L2c. Different from the flow path 20 in FIG. 3, in the flow path 20c in FIG. 11, since the second position detection line L2c is inclined with respect to the width direction of the flow path 20c, the position detection line Lc used for measuring the flow velocity v is inclined with respect to the width direction of the flow path 20c.

[0088] FIG. 12 is a diagram showing an example of the measurement signal SGc according to the third modified example. The first peak P1 at time t1 corresponds to the optical signal detected when the cell C passes through the first position detection line L1c. The second peak P2 at time t2 corresponds to the optical signal detected when the cell C passes through the second position detection line L2c. The fourth peak P4 at time t4 corresponds to the optical signal detected when the cell C passes through the fourth position detection line L4c.

[0089] Here, the longer the position detection distance D12 is, the longer the time difference τc between the first peak P1 and the second peak P2 in the measurement signal SGc becomes. The longer the time difference between the first peak P1 and the second peak P2 is, the higher the accuracy with which the time difference calculation unit 812 reads the times corresponding to the first peak P1 and the second peak P2 respectively becomes. That is, the longer the time difference between the first peak P1 and the second peak P2 is, the higher the time resolution for the first peak P1 and the second peak P2 becomes. The higher the time resolution for the first peak P1 and the second peak P2 is, the higher the accuracy of measuring the position x in the width direction of the flow path 20 of the cell C becomes. Therefore, by increasing the angle between the first position detection line L1c and the second position detection line L2c and making the position detection distance D12 long, the accuracy of measuring the position x in the width direction of the flow path 20 of the cell C by the arithmetic unit 81 becomes high.

[0090] Note that, as described above, in order to improve the measurement accuracy of the position x, it is preferable that the angle between the two position detection lines L is a predetermined angle (for example, 45 degrees) or more, but this angle may also be a predetermined angle (for example, 45 degrees) or less.

[0091] (Modification Example 4) Further, in the above-described embodiment, an example in the case where the position detection line L is a straight line has been described, but the present invention is not limited to this. In this Modification Example 4, an example in the case where the position detection line L is other than a straight line will be described.

[0092] FIG. 13 is a diagram showing an example of the position detection line Ld according to this Modification Example 4. The first position detection line L1d and the second position detection line L2d are position detection lines Ld for measuring the position x in the width direction of the flow path 20d of the cell C. The first position detection line L1d and the second position detection line L2d are curves. Here, the position detection distance D12d, which is the distance between the first position detection line L1d and the second position detection line L2d, monotonically changes according to the position in the width direction of the flow path 20d. Since the position detection distance D12d monotonically changes according to the position in the width direction of the flow path 20d, the position detection distance D12d and the position in the width direction of the flow path 20d correspond one-to-one.

[0093] Note that the position detection line L is not limited to a curve. The position detection line L may be a continuous line in the width direction of the flow path 20 as long as the position detection distance D12 monotonically changes according to the position in the width direction of the flow path 20. For example, the position detection line L may be a broken line. FIG. 14 is a diagram showing an example of another position detection line Le according to the present modification 4. The first position detection line L1e is a broken line. The second position detection line L2e is a straight line. The position detection distance D12e, which is the distance between the first position detection line L1e and the second position detection line L2e, monotonically changes according to the position in the width direction of the flow path 20e. Note that the second position detection line L2e may be a broken line as long as the position detection distance D12e monotonically changes according to the position in the width direction of the flow path 20e. Also, as long as the position detection distance D12e monotonically changes according to the position in the width direction of the flow path 20e, the first position detection line L1e may be a straight line and the second position detection line L2e may be a broken line.

[0094] Further, the position detection line L may be composed of a plurality of discrete line segments as long as the position detection distance D12d and the position in the width direction of the flow path 20 have a one-to-one correspondence. FIG. 15 is a diagram showing an example of yet another position detection line Lf according to the present modification 4. The first position detection line L1f and the second position detection line L2f are each composed of a plurality of discrete line segments. The first position detection line L1f is composed of a line segment L1f-1, a line segment L1f-2, and a line segment L1f-3. The second position detection line L2f is composed of a line segment L2f-1, a line segment L2f-2, and a line segment L2f-3. The position detection distance D12e, which is the distance between the first position detection line L1f and the second position detection line L2f, monotonically changes according to the position in the width direction of the flow path 20f.

[0095] In addition, when the position detection line Lf is composed of a plurality of discrete line segments, the gaps between these plurality of line segments are set to a pixel interval that is sufficiently small compared to the size of the cell C. As specific numerical values, for example, for cells about 5 to 30 micrometers in size, a gap of about 1 micrometer may be provided between the plurality of line segments. Alternatively, for larger cells such as 20 to 30 micrometers, a gap of 2 to 3 micrometers, which is about one-tenth of that, may be provided.

[0096] (Modification Example 5) Also, in the above-described embodiment, an example has been described in which the two position detection lines L (the first position detection line L1 and the second position detection line L2) for measuring the position x in the width direction of the flow path 20 of the cell C are in contact at one end, but the present invention is not limited to this. FIG. 16 is a diagram showing an example of the position detection line Lg according to this Modification Example 5. In the flow path 20g, the first position detection line L1g and the second position detection line L2g are not in contact at either end. That is, the minimum value of the position detection distance D12g, which is the distance between the first position detection line L1g and the second position detection line L2g, is a predetermined value that is not zero. Here, the position detection distance D12 and the position in the width direction of the flow path 20 change monotonically. Note that one of the first position detection line L1g and the second position detection line L2g may be arranged on the upstream side (-y direction in the y-axis direction) of the flow path 20 with respect to the detection region R, and the other may be arranged on the downstream side (+y direction in the y-axis direction).

[0097] (Modification Example 6) Also, in the above-described embodiment, an example has been described in which the length of the position detection line L in the width direction of the flow path 20 is equal to the width of the flow path 20, but the present invention is not limited to this. The length of the position detection line L may be shorter than the width of the flow path 20. For example, a range where the position detection line L is not arranged may be provided at both ends in the width direction of the flow path 20. FIG. 17 is a diagram showing an example of the position detection line Lh according to the sixth modified example. The length in the width direction of the flow path 20h of the first position detection line L1h and the length in the width direction of the flow path 20h of the second position detection line L2h are shorter than the width of the flow path 20h. That is, in the flow path 20h, the position detection lines Lh are not arranged at both ends in the width direction. Note that the length of the range where the position detection lines L are not arranged at both ends in the width direction of the flow path 20 is preferably narrow compared to the size of the cell C.

[0098] Further, when a range where the position detection lines L are not arranged at both ends in the width direction of the flow path 20 is provided, it is preferable that the cell C is controlled to flow near the center in the width direction (x-axis direction) of the flow path 20. For example, by generating a fluid flow from the side surface toward the center in the width direction (x-axis direction) of the flow path 20, the cell C can be controlled to flow near the center.

[0099] As described above, the flow cytometer 1 according to the present embodiment includes a microfluidic device 2, a light source 3, a photodetector 6, an information generation device (in the present embodiment, the information generation unit 80), and an arithmetic device (in the present embodiment, the arithmetic unit 81). The microfluidic device 2 includes a flow path 20 through which an object to be observed (in the present embodiment, the cell C) can flow together with a fluid. The light source 3 irradiates the flow path 20 with illumination light LE. The photodetector 6 detects, in time series, the intensity of an optical signal (in the present embodiment, the optical signal LS condensed by the light detection optical system 5) emitted from the object to be observed (in the present embodiment, the cell C) when the illumination light LE is irradiated on the object to be observed (in the present embodiment, the cell C) flowing through the flow path 20. The information generation device (in the present embodiment, the information generation unit 80) generates optical information indicating any one or more of the shape, form, or structure of the object to be observed (in the present embodiment, the cell C) based on electronic data obtained by converting the electrical signal pulses output by the photodetector 6. The arithmetic unit (the arithmetic unit 81 in the present embodiment) calculates the position x in the width direction of the flow path 20 of the object to be observed (the cell C in the present embodiment) based on the time when a peak is detected in the temporal change of the signal intensity of the optical signal LS detected by the photodetector 6.

[0100] Here, the microfluidic device 2 is a collection of a plurality of detection positions for the photodetector 6 to detect the position of the object to be observed (the cell C in the present embodiment) in the flow path 20, and a first position detection line L1, which is a position detection line L having a length at least in the width direction of the flow path 20, is arranged. A second position detection line L2, which is the position detection line L, is arranged so as to have a portion overlapping with the first position detection line L1 in the width direction of the flow path 20. The position detection distance D12, which is the distance in the length direction of the flow path 20 between the first position detection line L1 and the second position detection line L2, changes according to the position in the width direction of the flow path 20.

[0101] The arithmetic unit (the arithmetic unit 81 in the present embodiment) includes a time difference calculation unit 812 and a position calculation unit 815. The time difference calculation unit 812 calculates the time difference τ between the time when the photodetector 6 detects a peak in the intensity of the optical signal due to the passage of a cell at any detection position on the first position detection line L1 and the time when the photodetector 6 detects a peak in the intensity of the optical signal due to the passage of a cell at any detection position on the second position detection line L2. The position calculation unit 815 calculates the position x in the width direction of the flow path 20 of the object to be observed (the cell C in the present embodiment) based on the time difference τ calculated by the time difference calculation unit 812 and the correspondence relationship between the time difference τ and the position in the width direction of the flow path 20.

[0102] With this configuration, in the flow cytometer 1 according to the present embodiment, since the position x in the width direction of the flow path 20 of the object to be observed can be calculated, the displacement of the streamline can be detected. In the flow cytometer 1 according to the present embodiment, the position detection line L (in one example of the present embodiment, the first position detection line L1 and the second position detection line L2) for calculating the position x in the width direction of the flow path 20 of the object to be observed is arranged included in the illumination pattern for acquiring optical information regarding the morphological information of the cells, so that it can be easily arranged on the flow path 20. Even when a positional deviation of the streamline occurs, the position of the flow path can be appropriately corrected and the measurement under suitable conditions can be continued.

[0103] In the flow cytometer 1 according to the present embodiment, the position x in the width direction of the flow path 20 of the object to be observed can be calculated while measuring the object to be observed. In the above example, the method of controlling the position of the flow path with respect to the detected positional deviation of the streamline was described, but the information for correcting the positional deviation of the streamline and measuring the object to be observed is not limited to this. For example, it is also possible to correct the streamline deviation by moving the irradiation position according to the detected positional deviation of the streamline.

[0104] Further, the flow cytometer 1 according to the present embodiment further includes a flow path position control device 9. The flow path position control device 9 controls the position of the flow path 20 based on the calculation result of the arithmetic device (in the present embodiment, the arithmetic unit 81).

[0105] With this configuration, in the flow cytometer 1 according to the present embodiment, since the position of the flow path 20 can be controlled based on the calculation result of calculating the position x in the width direction of the flow path 20 of the object to be observed, the position of the flow path can be corrected with respect to the positional deviation of the streamline.

[0106] Further, in the flow cytometer 1 according to the present embodiment, in the flow path 20, a third position detection line L3 which is the position detection line L is arranged, and a fourth position detection line L4 which is the position detection line L and is substantially parallel to the third position detection line L3 is arranged at a flow velocity measurement distance D34 which is a predetermined distance from the third position detection line L3 and has a portion overlapping the third position detection line L3 in the width direction of the flow path 20. The arithmetic device (in the present embodiment, the arithmetic unit 81) further includes a flow velocity calculation unit 813 and a position detection distance calculation unit 814. The flow velocity calculation unit 813 calculates the flow velocity v of the fluid flowing through the flow path 20 based on the time when the photodetector 6 detects the peak of the intensity of the optical signal at any detection position on the third position detection line L3, the time when the photodetector 6 detects the peak of the intensity of the optical signal at any detection position on the fourth position detection line L4, and the flow velocity measurement distance D34. The position detection distance calculation unit 814 calculates the position detection distance D12 corresponding to the position x in the width direction of the flow path 20 of the observation object (the cell C in this embodiment) based on the time difference τ calculated by the time difference calculation unit 812 and the flow velocity v calculated by the flow velocity calculation unit 813.

[0107] With this configuration, in the flow cytometer 1 according to this embodiment, the flow velocity v of the fluid flowing through the flow path 20 can be sequentially measured, and the position x in the width direction of the flow path 20 of the observation object can be calculated using the measured value of the flow velocity v. Therefore, even when the flow velocity v of the fluid flowing through the flow path 20 fluctuates or deviates from the set value, the measurement can be continued under suitable conditions while correcting the position of the flow path with respect to the displacement of the streamline. Here, the flow velocity v of the fluid flowing through the flow path 20 is set by, for example, the microfluidic device 2, but there may be a case where the actual flow velocity v is different from the set flow velocity v. In the flow cytometer 1 according to this embodiment, since the flow velocity v can be measured simultaneously while flowing the observation object through the flow path 20, a more accurate value of the flow velocity v can be used to calculate the position detection distance D12 compared to the case of using the set value of the flow velocity v.

[0108] Also, in the flow cytometer 1 according to the first modification of this embodiment, the third position detection line L3 is also served by the second position detection line L2.

[0109] With this configuration, in the flow cytometer 1 according to the present embodiment, in the measurement signal SG, the third peak P3 corresponding to the optical signal detected when the cell C passes through the third position detection line L3 is combined with the second peak P2 corresponding to the optical signal detected when the cell C passes through the second position detection line L2, and is used both for the time difference calculation unit 812 to calculate the time difference τ and for the flow velocity calculation unit 813 to calculate the flow velocity v. Since it is possible to reduce the number of position detection lines arranged with this configuration, the configuration of the apparatus can be made simpler.

[0110] Also, in the flow cytometer 1 according to the present embodiment, the information generation device (in this embodiment, the information generation unit 80) generates optical information based on the intensity of the optical signal LS emitted from the observation object (in this embodiment, the cell C) irradiated with the illumination light (in this embodiment, the structured illumination light SLE) that has undergone a structuring process on the observation object (in this embodiment, the cell C) flowing through the flow path 20. The structuring process is performed by the configuration of the structured illumination. As described above, in the configuration of the structured illumination, the flow cytometer 1 includes a spatial light modulator 4 that is installed in the optical path between the light source 3 and the flow path 20 and structures the illumination light LE. In the configuration of the structured illumination, the light source 3 irradiates the flow path 20 with the illumination light (in this embodiment, the structured illumination light SLE) structured by the spatial light modulator 4. With this configuration, in the flow cytometer 1 according to the present embodiment, since it is possible to calculate the position x in the width direction of the flow path 20 in parallel with the generation of the optical information of the observation object by the structured illumination, it is possible to perform the measurement of the observation object using the structured illumination that is sensitive to the positional deviation while detecting the positional deviation of the streamline.

[0111] Also, in the flow cytometer 1 according to the present embodiment, the position detection line L is a continuous line in the width direction of the flow path 20, and the position detection distance D12 changes monotonically according to the position in the width direction of the flow path 20. With this configuration, in the flow cytometer 1 according to the present embodiment, since the position detection distance D12 and the position in the width direction of the flow path 20 correspond one-to-one, the position detection distance D12 can be converted into the position x in the width direction of the flow path 20 of the cell C.

[0112] Further, in the flow cytometer 1 according to the present embodiment, the length of the position detection line L in the width direction of the flow path 20 is equal to the width of the flow path 20. With this configuration, in the flow cytometer 1 according to the present embodiment, since there is no gap in the position detection line L in the width direction of the flow path 20, it is possible to prevent the cell C from passing through the position detection line L regardless of the size of the cell C and missing the measurement of the position x in the width direction of the flow path 20 of the cell C.

[0113] Further, in the flow cytometer 1 according to the present embodiment, the position detection line L is a straight line. With this configuration, in the flow cytometer 1 according to the present embodiment, the arrangement of the position detection line L in the flow path 20 is easier than when the position detection line L is not a straight line. As described above, the position detection line L is a collection of a plurality of detection positions, and those plurality of detection positions are realized as a pattern of structured illumination that is modulated by the spatial light modulation unit 4 and irradiated onto the flow path. The pattern of structured illumination is configured as a group of a plurality of irradiation regions with a light transmission region having a shape such as a square as a unit. Therefore, the shape of the position detection line L is easier to realize with a straight line than with a curve in units of those light transmission regions having a shape such as a square. Also, when making the position relationship between the position detection distance D12 and the width direction of the flow path 20 correspond one-to-one, the correspondence relationship is simple and the arrangement of the detection positions and the like are easy.

[0114] Further, in the flow cytometer 1 according to the third modification of the present embodiment, the angle between the first position detection line L1 and the second position detection line L2 is a predetermined value or more.

[0115] With this configuration, in the flow cytometer 1 according to the present embodiment, the position detection distance D12, which is the distance between the first position detection line L1 and the second position detection line L2, can be made longer than when the angle between the first position detection line L1 and the second position detection line L2 is less than a predetermined value, and the measurement accuracy of the time when the cell C passes through the first position detection line L1 and the time when the cell C passes through the second position detection line L2 can be improved. Therefore, the measurement accuracy of the position x in the width direction of the flow path 20 of the cell C can be improved.

[0116] Further, in the flow cytometer 1 according to the present embodiment, a spatial light modulation unit 4 for structuring the illumination light LE is provided in the optical path between the light source 3 and the flow path 20, and the position detection lines (in the present embodiment, the first position detection line L1 and the second position detection line L2) are arranged by the structured illumination light SLE. With this configuration, in the flow cytometer 1 according to the present embodiment, the arrangement of the position detection lines can be realized by structured illumination for acquiring optical information, so that the position detection lines can be easily set in the flow path 20.

[0117] (Second Embodiment) In the above description, an example in the case where the illumination light LE is structured by the spatial light modulator 40 has been described, but it is not limited to this. The spatial light modulation unit may be configured to include a mask instead of the spatial light modulator, and the object to be observed is irradiated with the illumination light structured by the mask. Structuring the illumination light means modulating the optical characteristics of the illumination light for each of a plurality of regions included in the incident surface of the mask of the illumination light. Referring to FIG. 18, the flow cytometer 1i according to the second embodiment will be described. FIG. 18 is a diagram showing an example of the flow cytometer 1i according to the second embodiment. The present embodiment is one configuration example of the configuration of structured illumination.

[0118] The configuration of the flow cytometer 1i (FIG. 18) is the same as the configuration of the flow cytometer 1 (FIG. 1) except that a spatial light modulation unit 4i is provided instead of the spatial light modulation unit 4. The spatial light modulation unit 4i includes a mask 40i and a first lens 41i. The mask 40i and the first lens 41i are arranged on the optical path between the light source 3 and the photodetector 6 in this order, closer to the light source 3 side.

[0119] The mask 40i is a spatial filter having a region that transmits light (light transmission region) and a region that does not transmit light. The arrangement of the light transmission regions of the mask 40i corresponds to the pattern of the structured illumination pattern 21. The mask 40i generates structured illumination light SLEi by transmitting and structuring the illumination light LE from the light source 3 through its light transmission regions. In this modification, the structured illumination pattern 21 is generated by the arrangement pattern of the light transmission regions of the mask 40i. The mask 40i is, for example, a film on which a plurality of regions with different optical characteristics are printed on the surface, or a filter having a region that transmits light and a region that does not transmit light.

[0120] The first lens 41i condenses the structured illumination light SLEi generated by the mask 40i and forms an image on the flow path 20. Here, the light transmission regions on the mask 40i and the structured illumination pattern 21 on the flow path 20 are in conjugate positions with respect to the first lens 41i.

[0121] As a configuration different from the above-described configuration, a configuration in which the structured illumination light SLEi is not imaged by the first lens 41i can also be adopted. When the structured illumination light SLEi is not imaged by the first lens 41i, the mask 40i is provided directly below the flow path 20 on the optical path between the light source 3 and the photodetector 6. Here, directly below the flow path 20 means extremely close to the light source 3 side of the flow path 20. When the structured illumination light SLEi is not imaged by a lens, the first lens 41i is omitted from the configuration of the spatial light modulation unit 4.

[0122] Furthermore, the spatial light modulation unit 4i may include a mirror 42i (not shown) that functions as a spatial filter instead of the mask 40i. The mirror 42i is a spatial filter having a region that transmits light (light transmission region) and a region that reflects light. In this case, the region of the mirror 42i that reflects light corresponds to the optical signal detection position. When the spatial light modulation unit 4i includes the mirror 42i, the light source 3 is provided on the side of the flow path 20 with respect to the mirror 42i.

[0123] (Third Embodiment) In the above description, the configurations of the spatial light modulation units 4 and 4i for modulating the illumination light LE in structured illumination have been described, but the present invention is not limited to this. Referring to FIG. 19, a flow cytometer 1j which is a flow cytometer according to the third embodiment will be described. FIG. 19 is a diagram showing an example of the flow cytometer 1j according to the third embodiment.

[0124] The configuration of the flow cytometer 1j (FIG. 19) is the same as that of the flow cytometer 1 (FIG. 1) except that it includes a spatial light modulation unit 4j and an illumination optical system 10j instead of the spatial light modulation unit 4. The spatial light modulation unit 4j includes a first lens 41j and a mask 40j. The first lens 41j and the mask 40j are arranged on the optical path between the light source 3 and the photodetector 6 in this order from the side closer to the light source 3.

[0125] The spatial light modulation unit 4j including the mask 40j is provided at a position in front of the optical system 5 for light detection and the photodetector 6 on the optical path between the light source 3 and the photodetector 6. That is, the optical signal LSj emitted from the cell C is irradiated onto the mask 40j through the first lens 41j and structured. Structuring an optical signal means modulating the optical characteristics of the signal light for each of a plurality of regions included in the incident surface of the mask of the optical signal. The configuration in which the spatial light modulation unit 4j is provided at a position on the side of the photodetector 6 with respect to the flow path 20 on the optical path between the light source 3 and the photodetector 6 as in the present embodiment is also referred to as a structured detection configuration. In structured detection, the structured optical signal SLSj structured by the mask 40j is detected by the photodetector 6 through the optical system for light detection.

[0126] The mask 40j is a spatial filter having a region that transmits light (light transmission region) and a region that does not transmit light. The light transmission region on the mask 40j and the position on the flow path 20 where the cell C is illuminated by the illumination optical system 10j are arranged at conjugate positions with respect to the first lens 41j. The illumination optical system 10j illuminates the cell C flowing through the flow path 20 with the illumination light LE from the light source 3. The first lens 41j condenses the optical signal LSj from the cell C and forms an image on the mask 40j. The photodetector 6 detects the structured optical signal SLSj structured through the light transmission region of the mask 40j. With the above configuration, in structured detection, the position conjugate to the light transmission region of the mask 40j can be arranged as an optical signal detection position for detecting the optical signal LS from the cell C passing through the flow path 20, and based on the optical signal detected by the photodetector 6 through the optical signal detection position, the optical information regarding the morphological information of the cell C and the position x in the width direction of the cell C are measured. That is, in structured detection, depending on the shape and arrangement pattern of the light transmission region provided in the mask 40j, the collection of position detections in the width direction of the flow path 20 can be arranged as the position detection line L. Note that arranging the position detection line by the configuration of structured detection as described above is also described as being arranged by the optical signal structured by the spatial light modulation unit.

[0127] Furthermore, the spatial light modulation unit 4j may include a mirror 42j (not shown) that functions as a spatial filter instead of the mask 40j. The mirror 42j is a spatial filter having a region that transmits light (light transmission region) and a region that reflects light. Here, the light transmission region of the mirror 42j corresponds to the optical signal detection position.

[0128] The spatial light modulation unit 4j (FIG. 19) and the spatial light modulation unit 4 (FIG. 1) differ in the type of light to be transmitted in the light transmission region, other than whether they are provided on the side of the light detector 6 or on the side of the light source 3 with respect to the flow path 20. The spatial light modulation unit 4 (FIG. 1) transmits the illumination light LE to form the structured illumination light SLE, while the spatial light modulation unit 4j (FIG. 19) transmits optical signals LSj such as fluorescence, transmitted light, scattered light, and interference light from the cell C, structures them, and forms the structured optical signal SLSj. The functions of the spatial light modulation unit 4j (FIG. 19) and the spatial light modulation unit 4 (FIG. 1) are the same except for the type of light to be transmitted in the light transmission region.

[0129] In addition, in the first embodiment and its modified examples, the case where the irradiation positions including the position detection line L are all set by the same one spatial light modulation unit has been described as an example, but it is not limited to this. For example, the first position detection line L1 and the second position detection line L2 may be set by the configuration of structured illumination such as the spatial light modulation unit 4 (FIG. 1), and the third position detection line L3 and the fourth position detection line L4 may be set by the configuration of structured detection such as the spatial light modulation unit 4j. Conversely, the third position detection line L3 and the fourth position detection line L4 may be set by the configuration of structured illumination such as the spatial light modulation unit 4 (FIG. 1), and the first position detection line L1 and the second position detection line L2 may be set by the configuration of structured detection such as the spatial light modulation unit 4j.

[0130] Furthermore, the first position detection line L1 and the second position detection line L2 are set by the configuration of structured illumination or structured detection by the spatial light modulation unit 4 (FIG. 1) or the spatial light modulation unit 4j (FIG. 19), and the third position detection line L3 and the fourth position detection line L4 may be set by an optical system with a configuration of only a normal lens or the like that is not structured by the spatial light modulation unit. In that case, the wavelength of the light used to set the first position detection line L1 and the second position detection line L2 and the wavelength of the light used to set the third position detection line L3 and the fourth position detection line L4 may be the same or different.

[0131] Furthermore, it is desirable that the optical information regarding the morphological information of cell C generated by the information generation device based on the optical signal is based on the optical signal emitted from cell C irradiated with the structured illumination light SLE obtained by subjecting the illumination light LE to a structuring process, or on the optical signal that has undergone the structuring process. However, the structuring process for this purpose may be performed by the configuration of structured illumination or may be performed by the configuration of structured detection. Furthermore, when the optical signal by which the information generation device generates optical information and the optical signal by which the arithmetic device calculates the position in the width direction are subjected to a structuring process, it is desirable that the structuring process is performed by the same method, but they may be subjected to the structuring process by different methods. Here, performing the structuring process means modulating the optical characteristics of the illumination light from the light source or the optical signal detected by the photodetector through the spatial light modulation unit by the configuration of structured illumination or the configuration of structured detection. That is, performing the structuring process means structuring the illumination light or the optical signal.

[0132] In the flow cytometer 1j according to the present embodiment, the information generation device (in the present embodiment, the information generation unit 80) generates optical information based on the intensity of the optical signal that has undergone the structuring process (in the present embodiment, the structured optical signal SLSj). The structuring process is performed by the configuration of structured detection. As described above, in the configuration of structured detection, the flow cytometer 1j includes a spatial light modulation unit 4j that is installed in the optical path between the flow path 20 and the photodetector 6 and structures the optical signal LSj. In the configuration of structured detection, the photodetector 6 detects the intensity of the optical signal (in the present embodiment, the structured optical signal SLSj) in which the optical signal LSj is structured by the spatial light modulation unit 4j in time series.

[0133] With this configuration, in the flow cytometer 1j according to the present embodiment, the optical signal LS emitted from the object to be observed (in the present embodiment, the cell C) is structured by the configuration for structured detection, and optical information can be generated based on the intensity of the structured optical signal. In the flow cytometer 1j, since the position x in the width direction of the flow path 20 of the object to be observed can be calculated in parallel with the generation of the optical information of the object to be observed by the configuration for structured detection, it is possible to perform measurement of the object to be observed in the structured detection that is sensitive to the positional deviation while detecting the positional deviation of the streamline.

[0134] In the flow cytometers 1, 1i, and 1j according to the above-described embodiments, the information generation device (in each embodiment, the information generation unit 80) irradiates the illumination light (in the first and second embodiments, the structured illumination lights SLE and SLEi, respectively) that has been subjected to the structuring process to the object to be observed (in each embodiment, the cell C) flowing through the flow path 20, and generates optical information based on the intensity of the optical signal emitted from the object to be observed (in each embodiment, the cell C), or the intensity of the optical signal that has been subjected to the structuring process (in the third embodiment, the structured optical signal SLSj).

[0135] With this configuration, in the flow cytometers 1, 1i, and 1j according to the embodiments, when the illumination light that has been subjected to the structuring process is irradiated to the object to be observed flowing through the flow path 20, or when the illumination light is irradiated to the object to be observed and the optical signal emitted from the object to be observed is subjected to the structuring process, the position x in the width direction of the flow path 20 of the object to be observed can be calculated. Therefore, in those cases, it is possible to obtain the optical information of the object to be observed while detecting the positional deviation of the streamline.

[0136] Further, in the flow cytometer 1j according to the present embodiment, a spatial light modulation unit 4j is provided which is installed in the optical path between the flow path 20 and the photodetector 6 and structures the optical signal LSj so that the intensity of the optical signal LSj emitted from the object to be observed (in the present embodiment, the cell C) is detected by the photodetector 6 at the position detection lines (in the present embodiment, the first position detection line L1 and the second position detection line L2). With this configuration, in the flow cytometer 1 according to the present embodiment, since the arrangement of the position detection lines can be realized by structured detection for acquiring optical information, the position detection lines can be easily set in the flow path 20.

[0137] (Fourth Embodiment) Hereinafter, the fourth embodiment of the present invention will be described in detail with reference to the drawings. In the above first embodiment, the case where the flow cytometer measures the flow velocity of the fluid flowing through the flow path and uses the value to measure the position of the observation object in the width direction of the flow path was described. In the present embodiment, the case where the flow cytometer measures the position of the observation object in the width direction of the flow path without using the flow velocity will be described. Note that in the present embodiment, the flow velocity of the fluid flowing through the flow path is constant. The flow cytometer according to the present embodiment is referred to as a flow cytometer 1k, and the arithmetic device is referred to as an arithmetic unit 81k.

[0138] FIG. 20 is a diagram showing an example of the flow cytometer 1k according to the present embodiment. The flow cytometer 1k includes a microfluidic device 2, a light source 3, a spatial light modulation unit 4, an optical system for light detection 5, a photodetector 6, a DAQ device 7, a PC 8k, and a flow path position control device 9. Comparing the flow cytometer 1k (FIG. 20) according to the present embodiment with the flow cytometer 1 (FIG. 1) according to the first embodiment, the PC 8k is different. Here, the functions of the other components (the microfluidic device 2, the light source 3, the spatial light modulation unit 4, the optical system for light detection 5, the photodetector 6, the DAQ device 7, and the flow path position control device 9) are the same as those in the first embodiment. The description of the same functions as in the first embodiment will be omitted, and in the second embodiment, the description will focus on the parts different from the first embodiment.

[0139] In the flow cytometer 1k, the position x in the width direction of the flow path 20 of the cell C is measured without using the flow velocity v. In the flow cytometer 1k, the position of the optical system is adjusted in advance so that the sensitivity of the optical system is maximized. The flow cytometer 1k measures, in advance, as a reference time difference τ0, the time difference τ between the time when the cell C passes through the first position detection line L1 and the time when the cell C passes through the second position detection line L2. The flow cytometer 1k measures the position x using a table showing the relationship between the deviation of the time difference τ from the reference time difference τ0 and the position x in the width direction of the flow path 20 of the cell C. The flow cytometer 1k compares the measured time difference τ based on the measured position x with the reference time difference τ0, and controls the position of the flow path 20 so that the deviation Δτ of the time difference τ from the reference time difference τ0 becomes small. Here, the reference time difference τ0 serving as a reference can be, for example, the time difference τ between the time when the cell C passes through the first position detection line L1 and the time when the cell C passes through the second position detection line L2 when the cell C moves on the streamline at the above-mentioned reference position. As another example of the reference time difference τ0, the time difference τ between the time when the cell C passes through the first position detection line L1 and the time when the cell C passes through the second position detection line L2 is measured for a certain number of cells C, and the average value thereof can be set as the reference time difference τ0.

[0140] Next, with reference to FIGS. 21 and 22, the configuration and details of the processing of the arithmetic unit 81k will be described. FIG. 21 is a diagram showing an example of the arithmetic unit 81k according to the present embodiment. The arithmetic unit 81k includes a control unit 810k and a storage unit 817k.

[0141] The control unit 810 includes a signal intensity acquisition unit 811, a time difference calculation unit 812, a position calculation unit 815k, and an output unit 816. Comparing the control unit 810k (FIG. 21) according to the present embodiment with the control unit 810 (FIG. 4) according to the first embodiment, the differences are that the position calculation unit 815k is provided, and the flow velocity calculation unit 813 and the position detection distance calculation unit 814 are omitted. Here, the functions of the other components (the signal intensity acquisition unit 811, the time difference calculation unit 812, and the output unit 816) are the same as those in the first embodiment. The description of the same functions as in the first embodiment is omitted, and in the second embodiment, the description will be centered on the parts different from the first embodiment.

[0142] The position calculation unit 815k calculates the position in the width direction of the object to be observed based on the correspondence between the time difference τ calculated by the time difference calculation unit 812 and the position x in the width direction of the flow path 20 of the cell C. That is, in the present embodiment, based on the time difference width direction correspondence table 818k, which is a table showing the correspondence between the deviation Δτ of the time difference τ from the reference time difference τ0 and the position x in the width direction of the flow path 20 of the cell C, the position x in the width direction of the flow path 20 of the cell C is calculated.

[0143] The storage unit 817k stores the time difference width direction correspondence table 818k. The time difference width direction correspondence table 818k is, for example, two-dimensional table-form data composed of rows and columns in which the values of the position x in the width direction of the flow path 20 of the cell C are stored for each deviation Δτ of the time difference τ from the reference time difference τ0. Here, the time difference width direction correspondence table 818k is created based on the results of previously measuring the deviation Δτ of the time difference τ from the reference time difference τ0 and the position x in the width direction of the flow path 20 of the cell C. Note that the measurement of the position x performed in advance may be performed based on the method of the first embodiment based on the flow velocity v described above, or may be performed based on other measurement methods.

[0144] FIG. 22 is a diagram showing an example of the position calculation process according to the present embodiment. Since the processes of step S110 and step S120 are the same as the processes of step S10 and step S20 in FIG. 5, the description thereof is omitted.

[0145] Step S130: The position calculation unit 815k calculates the position x in the width direction of the flow path 20 of the cell C based on the deviation Δτ of the time difference τ calculated by the time difference calculation unit 812 from the reference time difference τ0 and the time difference width direction correspondence table 818k. Here, the position calculation unit 815k reads out the value of the position in the width direction of the flow path 20 corresponding to the deviation Δτ from the time difference width direction correspondence table 818k. The position calculation unit 815k sets the read position value as the position x in the width direction of the flow path 20 of the cell C. In other words, the position calculation unit 815k calculates the position x by converting the deviation Δτ into the position in the width direction of the flow path 20 based on the time difference width direction correspondence table 818k.

[0146] In this embodiment, an example in which the deviation Δτ of the time difference τ from the reference time difference τ0 is measured for one cell flowing through the flow path and the position of the flow path is corrected for the position deviation of the streamline has been described, but it is not limited thereto. Based on the results of measuring the positions in the width directions of the flow paths of the respective cells for a plurality of cells flowing through the flow path, the position of the flow path may be corrected for the position deviation of the streamline.

[0147] For example, it is assumed that 1000 cells C pass through the flow path 20 per minute. Each time a cell C passes through the position detection line L for measuring the position x in the width direction of the flow path 20 of the cell C, the flow cytometer 1k measures the position x. That is, the flow cytometer 1k measures the position x 1000 times. The flow cytometer 1k corrects the position of the flow path once a minute based on the 1000 measurement results of the position x.

[0148] The flow cytometer 1k corrects the position of the flow path based on the average value of 1000 measurement results at the position x. By correcting the position of the flow path using the average value of a plurality of measurement results, in calculating the position x in the width direction of the flow path 20 of the cell C, it is possible to correct the position of the flow path considering the variation in the deviation Δτ with respect to the reference time difference τ0 of the time difference τ, and it is possible to suppress the influence of the variation. Further, by continuously correcting the position of the flow path, it is possible to appropriately correct the positional deviation of the streamline due to the change that occurs with the passage of the measurement time in the microfluidic device, and minimize the influence of the positional shift. By the measurement method described above, the positional deviation of the streamline can be made less than or equal to the pixel size. Here, the pixel size is several micrometers.

[0149] As described above, the flow cytometer 1k according to the present embodiment includes a position calculation unit 815k. The position calculation unit 815k calculates the difference (in this embodiment, the deviation Δτ) with respect to a predetermined value (in this embodiment, the reference time difference τ0) of the time difference τ calculated by the time difference calculation unit 812, and the difference (in this embodiment, the deviation Δτ) with respect to a predetermined value (in this embodiment, the reference time difference τ0) of the time difference τ, and based on a table (in this embodiment, the time difference width direction correspondence table 818k) showing the correspondence relationship with the position x in the width direction of the flow path 20 of the observation object (in this embodiment, the cell C), calculates the position x in the width direction of the flow path 20 of the observation object (in this embodiment, the cell C).

[0150] With this configuration, in the flow cytometer 1k according to the present embodiment, when the flow velocity v of the fluid flowing through the flow path 20 is constant, based on a table (in this embodiment, the time difference-width direction correspondence table 818k) showing the correspondence between the difference (in this embodiment, the deviation Δτ) with respect to a predetermined value of the time difference τ (in this embodiment, the reference time difference τ0) and the position x in the width direction of the flow path 20 of the cell C, the position x in the width direction of the flow path 20 of the observation object (in this embodiment, the cell C) can be calculated from the time difference τ. Therefore, without measuring the flow velocity v of the fluid flowing through the flow path 20, based on the time difference τ between the times when the cell C passes through the first position detection line L1 and the second position detection line L2, and the correspondence between the time difference τ and the position in the width direction, the position of the flow path can be corrected for the streamline position deviation. Therefore, compared with the case where three or more position detection lines are arranged, measurement can be performed with a simple configuration that minimizes the influence of the streamline position deviation.

[0151] Note that the flow cytometer according to each of the above-described embodiments may have the function of a cell sorter. The flow cytometer sorts cells based on information indicating the morphology of the cells included in the optical information generated by the information generation device (information generation unit 80). Sorting means separating predetermined cells from among the observation objects flowing through the flow path. These predetermined cells are, for example, preselected by the user.

[0152] Note that the flow cytometer according to each of the above-described embodiments may be combined with an image generation device and provided as part of an imaging device. This image generation device includes an image generation unit that generates an image of the observation object (cell C) based on the optical information generated by the information generation device (information generation unit 80).

[0153] (Fifth Embodiment) Hereinafter, the fifth embodiment of the present invention will be described in detail with reference to the drawings. In the present embodiment, a case will be described in which cells flowing through a flow path are discriminated based on optical information generated by an information generation device. In the present embodiment, the width direction of the flow path 20 is also referred to as the horizontal direction. In this embodiment, the direction of the optical axis OX of the imaging lens 50 (not shown) included in the optical system 5 for light detection in the flow path 20 is referred to as the optical axis direction. The direction of the optical axis OX is the depth direction of the flow path. Also, the horizontal position and the position in the optical axis direction of the cell C are referred to as the horizontal position and the optical axis direction position, respectively. The horizontal position is the same as the position x in the width direction of the flow path 20.

[0154] The flow cytometer according to this embodiment is referred to as flow cytometer 1m, and the arithmetic unit is referred to as arithmetic unit 81m. The configuration of the flow cytometer 1m is, as an example, the same as the configuration of the flow cytometer 1 according to the first embodiment, except that the arithmetic unit 81m is different. The description of the same functions as in the first embodiment is omitted, and in the fifth embodiment, the description will focus on the parts different from the first embodiment. Note that the configuration of the flow cytometer 1m may be the same as the configuration of the modified example of the first embodiment or the flow cytometers according to the second, third, and fourth embodiments for the configurations other than the arithmetic unit 81m.

[0155] [Arithmetic device] FIG. 23 is a diagram showing an example of the configuration of the arithmetic unit 81m according to this embodiment. Comparing the arithmetic unit 81m (FIG. 23) according to this embodiment with the arithmetic device 10 (FIG. 4) according to the first embodiment, the optical information acquisition unit 820m, the position determination unit 821m, the discrimination unit 822m, the learning unit 823m, and the storage unit 817m are different. Here, the functions of the other components (signal intensity acquisition unit 811, time difference calculation unit 812, flow velocity calculation unit 813, position detection distance calculation unit 814, position calculation unit 815, and output unit 816) are the same as those in the first embodiment.

[0156] The control unit 810m includes, in addition to the signal intensity acquisition unit 811, the time difference calculation unit 812, the flow velocity calculation unit 813, the position detection distance calculation unit 814, the position calculation unit 815, and the output unit 816, an optical information acquisition unit 820m, a position determination unit 821m, a discrimination unit 822m, and a learning unit 823m.

[0157] The optical information acquisition unit 820m acquires the optical information IC generated by the PC8. The position determination unit 821m determines whether or not the position x (horizontal position) in the width direction of the flow path 20 of the cell C output by the output unit 816 is within a predetermined range in the width direction of the flow path 20. In the following description, the information indicating the position x (horizontal position) in the width direction of the flow path 20 of the cell C is referred to as position information IP. The discrimination unit 822m learns the relationship between the learning cells and the optical information IC about the learning cells, and discriminates the cell C based on the created inference model and the optical information IC generated by the PC8. At this time, the discrimination unit 822m sets, as a discrimination target, the cell C flowing in the region Z1, which is a predetermined range at the horizontal position of the flow path 20, based on the determination result of the position determination unit 821m.

[0158] Here, referring to FIG. 24, the above-described region Z1 will be described. FIG. 24 is a diagram showing an example of the region Z1 according to the present embodiment. FIG. 24 is a histogram showing, for each predetermined section, the number of cells C whose measured values of the horizontal position are included in the predetermined section when the horizontal position when the cell C flowing through the flow path 20 passes through the flow path 20 is measured and the range of values that can be taken for the horizontal position of the flow path 20 is divided into predetermined sections. The discrimination unit 822m sets, as a discrimination target, the optical information IC of the cell C corresponding to the measured value passing through the section included in the region Z1 among the cells C passing through the flow path 20. The region Z1 is, for example, a line segment up to a section including a position shifted by a predetermined distance from the passing position of the initial cell C at the horizontal position of the flow path 20.

[0159] Note that, instead of directly using the measured value of the horizontal position, the position determination unit 821m may determine whether or not the cell C flowing through the flow path 20 is included in the region corresponding to the region Z1 based on the measured value of the quantity related to the horizontal position.

[0160] Returning to FIG. 23, the description of the configuration of the calculation unit 81m will be continued. The learning unit 823m executes machine learning. The learning unit 823m learns the relationship between the learning cells and the optical information obtained by measurement using the learning cells. The machine learning executed by the learning unit 823m is, for example, deep learning.

[0161] The learning cells are the cells C flowing in region Z1. In the present embodiment, the cells C are measured using the flow cytometer 1m, and machine learning is executed using the measured values of the cells C flowing in region Z1 of the flow path 20 at the time of measurement as teacher data. Here, referring to FIG. 25, region Z1 of the above-described learning cells will be described. FIG. 25 is a diagram showing an example of region Z1 of the learning cells according to the present embodiment. In FIG. 25(A), when performing learning measurement using the flow cytometer 1m, the horizontal position where the cells passed is measured, and when the range of possible values for the horizontal position of the flow path is divided into predetermined intervals, a histogram showing the number of cells C whose measured values of the horizontal position are included in each predetermined interval is shown. For comparison, FIG. 25(B) shows a histogram showing the number of cells C whose measured values of the horizontal position are included in each predetermined interval when the horizontal position where the cells C passed during the inference of machine learning is measured and the range of possible values for the horizontal position is divided into predetermined intervals. In the present embodiment, the learning cells used by the learning unit 823m for learning are the cells C flowing in region Z1. This region Z1 is the same as the region Z1 through which the cells C to be discriminated during inference by the discrimination unit 822m flow. That is, the learning cells are the cells C flowing in the same region Z1 as the region Z1 through which the cells C to be discriminated by the discrimination unit 822m flow.

[0162] Returning to FIG. 23, the description of the configuration of the calculation unit 81m will be continued. The storage unit 817m stores various information. The information stored in the storage unit 817m includes the learning result 824m. The learning result 824m is the result of learning executed by the learning unit 823m. The learning result 824m is the above-described inference model. The learning result 824m is stored in the storage unit 817m after learning is executed in advance.

[0163] [Cell Discrimination Process] Next, referring to FIG. 26, the cell discrimination process, which is a process in which the arithmetic unit 81m discriminates cells C, will be described. FIG. 26 is a diagram showing an example of the cell discrimination process according to the present embodiment. The cell discrimination process shown in FIG. 26 is executed for one cell C. The cell discrimination process executed for a plurality of cells flowing through the flow path 20 is repeatedly executed for a plurality of cells with the cell discrimination process shown in FIG. 26 as one unit.

[0164] Step S210: The position determination unit 821m acquires the position information IP output by the output unit 816. Here, the position information IP indicates the horizontal position of the cell C. Step S220: The position determination unit 821m determines whether or not the horizontal position of the cell C indicated by the position information IP output by the output unit 816 is within a region Z1 that is a predetermined range in the width direction of the flow path 20.

[0165] When the position determination unit 821m determines that the horizontal position is within the region Z1 in the width direction of the flow path 20 (Step S220; YES), the control unit 810m executes the process of Step S230. On the other hand, when the position determination unit 821m determines that the horizontal position is not within the region Z1 in the width direction of the flow path 20 (Step S220; NO), the control unit 810m ends the cell discrimination process.

[0166] Step S230: The optical information acquisition unit 820m acquires the optical information IC generated by the PC8. The optical information acquisition unit 820m supplies the acquired optical information IC to the discrimination unit 822m.

[0167] Step S240: The discrimination unit 822m discriminates the cell C based on the learning result 824m and the optical information IC generated by the PC8. Here, as described above, the learning result 824m is the result of learning the relationship between the learning cells and the optical information about the learning cells. For example, when deep learning is used as machine learning, the learning result 824m indicates a neural network that has been trained to output the type of cell when optical information is input.

[0168] The discrimination unit 822m inputs the optical information IC generated by the PC 8 into the neural network indicated by the learning result 824m. The discrimination unit 822m determines whether the cell type output by the neural network indicated by the learning result 824m is the desired cell type.

[0169] The process in step S240 is executed when the position determination unit 821m determines in the process of step S220 that the horizontal position is within the region Z1 in the width direction of the flow path 20. That is, the discrimination unit 822m targets the cell C flowing within the region Z1, which is a predetermined range, for discrimination based on the determination result of the position determination unit 821m.

[0170] Step S250: The discrimination unit 822m outputs the discrimination result to an external device via the output unit 816. Here, the external device is, for example, a sorting unit that sorts the cell C. When the flow cytometer 1m includes a sorting unit, the flow cytometer 1m functions as a cell sorter. With the above, the arithmetic unit 10 ends the cell discrimination process.

[0171] Note that in this embodiment, an example has been described where the learning unit 823m is provided in the arithmetic unit 81m and the arithmetic device 10 executes machine learning, but it is not limited to this. Machine learning may be executed by an external device. When machine learning is executed by an external device, the arithmetic unit 81m acquires the learning result of machine learning executed by the external device from the external device, stores it in the storage unit 817m, and uses it for the cell discrimination process.

[0172] [Summary of the Fifth Embodiment] As described above, in the flow cytometer 1m according to this embodiment, the arithmetic device (the arithmetic unit 81m in this embodiment) includes a discrimination unit 822m and a position determination unit 821m. The discrimination unit 822m discriminates the observation object (the cell C in this embodiment) based on the optical information IC generated by the information generation device (the information generation unit 80 in this embodiment). The position determination unit 821m determines whether the position x in the width direction of the flow path 20 calculated by the position calculation unit 815 is within a predetermined range (region Z1 in this embodiment) in the width direction of the flow path 20. Based on the determination result of the position determination unit 821m, the discrimination unit 822m targets the observation object (cell C in this embodiment) flowing within a predetermined range (region Z1 in this embodiment) for discrimination.

[0173] With this configuration, in the flow cytometer 1m according to this embodiment, since the observation object flowing within a predetermined range in the flow path 20 can be targeted for discrimination, it is possible to reduce the dependence of the analysis result (optical information IC) for discriminating the observation object on the streamline position deviation. In the flow cytometer 1m according to this embodiment, gating is performed based on the position x in the width direction of the flow path 20, and more robust data analysis can be realized compared to the case where gating is not performed.

[0174] Also, in the flow cytometer 1m according to this embodiment, the discrimination unit 822m discriminates the observation object (cell C in this embodiment) based on the inference model (learning result 824m in this embodiment) created by learning the relationship between the learning observation object (learning cell in this embodiment) and the optical information about the learning observation object (learning cell in this embodiment), and the optical information IC generated by the information generation device (information generation unit 80 in this embodiment). Also, the learning observation object (learning cell in this embodiment) is an observation object (cell in this embodiment) flowing within a predetermined range (region Z1 in this embodiment).

[0175] With this configuration, in the flow cytometer 1m according to the present embodiment, a discrimination process can be executed based on an inference model (learning result 824m in the present embodiment) created by learning the relationship between an object to be observed flowing within a predetermined range and optical information about the object to be observed for learning. Therefore, the influence of the positional deviation in the width direction of the streamline on the learning result 824m can be made smaller than when the object to be observed for learning is not limited to the object to be observed flowing within a predetermined range, and it is possible to suppress a decrease in the accuracy of machine learning based on the learning result 824m due to the positional deviation of the streamline.

[0176] Note that a part of the arithmetic units 81, 81k, 81m in the above-described embodiment, for example, the time difference calculation unit 812, the flow velocity calculation unit 813, the position detection distance calculation unit 814, and the position calculation units 815, 815k may be realized by a computer. In that case, a program for realizing this control function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed to realize it. Here, the "computer system" refers to a computer system built in the arithmetic units 81, 81k and includes hardware such as an OS and peripheral devices. Further, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, etc., and a storage device such as a hard disk built in a computer system. Furthermore, the "computer-readable recording medium" also includes those that hold a program dynamically for a short time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, and those that hold a program for a certain time, such as a volatile memory inside a computer system serving as a server or a client in that case. Also, the above program may be for realizing a part of the above-described functions, and may further be realized in combination with a program already recorded in the computer system for realizing the above-described functions. Further, part or all of the arithmetic units 81 and 81k in the above-described embodiments may be realized as an integrated circuit such as an LSI (Large Scale Integration). Each functional block of the arithmetic units 81, 81k, and 81m may be individually processed as a processor, or part or all of them may be integrated and processed as a processor. Also, the method of integrating into a circuit is not limited to an LSI, and it may be realized by a dedicated circuit or a general-purpose processor. Further, when a technology for integrating into a circuit that replaces an LSI appears due to the progress of semiconductor technology, an integrated circuit using such technology may be used.

[0177] As described above, one embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the gist of the present invention.

Explanation of Reference Numerals

[0178] 1, 1i, 1j, 1m... flow cytometer, 2... microfluidic device, 20, 20a, 2 0b, 20c, 20d, 20e, 20f, 20g, 20h... flow paths, 3... light source, 6... photodetector 80... information generation unit, 81, 81k, 81m... arithmetic units, 9... flow path position control device, L... position detection line, L1, L1a, L1b, L1c, L1d, L1e, L1f, L1g, L1h... first position detection line, L2, L2a, L2b, L2c, L2d, L2e, L2f, L2g, L 2h... second position detection line, 812... time difference calculation unit, 815... position calculation unit ​

Claims

1. A microfluidic device having a flow path through which an object to be observed can flow together with a fluid; a light source that irradiates the flow channel with illumination light; a photodetector configured to irradiate the object to be observed flowing through the flow path with illumination light and detect the intensity of an optical signal emitted from the object to be observed in a time series manner; an information generating device that generates optical information indicating at least one of a shape, a form, and a structure of the observed object based on the intensity of the optical signal detected by the optical detector; a calculation device that calculates a position of the object in the width direction of the flow channel based on a time when the photodetector detects a peak of the intensity of the optical signal; a spatial light modulation unit disposed in an optical path between the light source and the photodetector, the spatial light modulation unit structuring the illumination light; A flow cytometer comprising: The microfluidic device includes a position detection line, which is a collection of a plurality of detection positions at which the photodetector detects the position of the observation object, and a plurality of detection positions at which the photodetector detects the optical information, disposed in the flow path; the plurality of detection positions for detecting the optical information are arranged in a detection region of the flow channel by the illumination light structured by the spatial light modulation unit; the position detection line includes a first position detection line that is disposed at a position different from the detection region in a longitudinal direction of the flow channel and has a length in at least the width direction, and a second position detection line that is disposed to have a portion that overlaps with the first position detection line in the width direction, a position detection distance, which is a distance between the first position detection line and the second position detection line in a length direction of the flow channel, changes monotonically depending on a position in the width direction, The flow rate of the fluid is constant, the calculation device includes a time difference calculation unit that calculates a time difference between a time when the photodetector detects a peak of intensity of the optical signal at any one of the detection positions on the first position detection line and a time when the photodetector detects a peak of intensity of the optical signal at any one of the detection positions on the second position detection line; and a position detection distance calculation unit that calculates the position detection distance based on the time difference calculated by the time difference calculation unit and a flow velocity of the fluid; a position calculation unit that calculates the position of the observed object in the width direction based on a correspondence relationship between the position detection distance and a position in the width direction, or a correspondence relationship between a deviation between the time difference calculated by the time difference calculation unit and a reference time difference measured in advance, and the position in the width direction; Equipped Flow cytometer.

2. The first position detection line and the second position detection line are arranged in the detection area by being subjected to a structuring process in a manner different from that of the plurality of detection positions for detecting the optical information.

2. The flow cytometer of claim 1.

3. a flow path position control device that controls the position of the flow path based on the calculation result of the calculation device 2. The flow cytometer of claim 1.

4. The position detection line is a straight line.

2. The flow cytometer of claim 1.

5. The angle between the first position detection line and the second position detection line is equal to or greater than a predetermined value.

5. The flow cytometer of claim 4.

6. In the flow path, a third position detection line is disposed as the position detection line; a fourth position detection line, which is one of the position detection lines and is substantially parallel to the third position detection line, is disposed at a distance from the third position detection line that is a predetermined flow velocity measurement distance and has a portion overlapping with the third position detection line in the width direction; the arithmetic device further includes a flow velocity calculation unit that calculates a flow velocity of the fluid based on a time when the photodetector detects a peak of intensity of the optical signal at any one of the detection positions on the third position detection line, a time when the photodetector detects a peak of intensity of the optical signal at any one of the detection positions on the fourth position detection line, and the flow velocity measurement distance, The position detection distance calculation unit calculates the position detection distance based on the time difference calculated by the time difference calculation unit and the flow velocity calculated by the flow velocity calculation unit.

2. The flow cytometer of claim 1.

7. The third position detection line and the fourth position detection line are arranged in the detection region by an optical system that does not perform a structuring process in which the illumination light is structured by the spatial light modulation unit.

7. The flow cytometer of claim 6.

8. Any one of the first position detection line and the second position detection line is also used as any one of the third position detection line and the fourth position detection line.

7. The flow cytometer of claim 6.

9. A microfluidic device having a flow path through which an object to be observed can flow together with a fluid; a light source that irradiates the flow channel with illumination light; a photodetector configured to irradiate the object to be observed flowing through the flow path with illumination light and detect the intensity of an optical signal emitted from the object to be observed in a time series manner; an information generating device that generates optical information indicating at least one of a shape, a form, and a structure of the observed object based on the intensity of the optical signal detected by the optical detector; a calculation device that calculates a position of the object in the width direction of the flow channel based on a time when the photodetector detects a peak of the intensity of the optical signal; a spatial light modulation unit disposed in an optical path between the light source and the photodetector, for structuring either the illumination light or the optical signal; Equipped with The microfluidic device includes a position detection line, which is a collection of a plurality of detection positions at which the photodetector detects the position of the observation object, and a plurality of detection positions at which the photodetector detects the optical information, disposed in the flow path; the plurality of detection positions for detecting the optical information are arranged in a detection region of the flow channel by the illumination light structured by the spatial light modulation unit; the position detection line includes a first position detection line that is disposed at a position different from the detection region in a longitudinal direction of the flow channel and has a length in at least the width direction, and a second position detection line that is disposed to have a portion that overlaps with the first position detection line in the width direction, a position detection distance, which is a distance between the first position detection line and the second position detection line in a length direction of the flow channel, changes monotonically depending on a position in the width direction, The flow rate of the fluid is constant. A method for calculating a position in the width direction of an observation object in a flow cytometer, comprising: a time difference calculation process for calculating a time difference between a time when the photodetector detects a peak of the intensity of the optical signal at any one of the detection positions on the first position detection line and a time when the photodetector detects a peak of the intensity of the optical signal at any one of the detection positions on the second position detection line; a position calculation process for calculating the widthwise position of the object to be observed based on a correspondence relationship between the time difference calculated in the time difference calculation process and a position in the widthwise direction of the position detection distance calculated based on a flow velocity of the fluid, or based on a correspondence relationship between a deviation between the time difference calculated in the time difference calculation process and a reference time difference measured in advance, which serves as a reference, and a position in the widthwise direction; have A method for detecting position in a flow cytometer.

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