Particle size distribution measuring device, particle size distribution measuring method, and imaging unit arrangement method

Abstract

In order to provide a particle size distribution measuring device in which a first imaging unit 51 and a second imaging unit 52, which are different from each other, can image a sample within a cell 2 without affecting the detection of diffracted light and / or scattered light by a detector, an angle formed by the normal line N of an imaging surface of the cell 2 and an imaging axis C1 of the first imaging unit 51 is different from an angle formed by the normal line N of the imaging surface of the cell 2 and an imaging axis C2 of the second imaging unit 52.

Description

Particle size distribution measuring device, particle size distribution measuring method, and imaging unit arrangement method

[0001] The present invention relates to a particle size distribution measuring device, a particle size distribution measuring method, and a method for arranging an imaging unit.

[0002] 2. Description of the Related Art Conventionally, there are laser diffraction / scattering particle size distribution measuring devices that use the diffraction phenomenon and Mie scattering phenomenon to measure the particle size distribution of particles contained in a sample.

[0003] As disclosed in Patent Document 1, for example, this type of laser diffraction / scattering particle size distribution measuring device includes a cell in which a sample flows, a laser light source that irradiates laser light onto the sample flowing through the cell, and a detector that detects transmitted light and scattered light generated from the sample by the laser light irradiated from the laser light source.

[0004] Japanese Patent Application Laid-Open No. 2003-28778

[0005] The particle size distribution measuring device may include an imaging unit such as a camera to capture an image of the sample and perform image analysis based on the captured image. Conventionally, the imaging unit has been provided at a location separate from the cell through which the sample flows, and the image of the sample is captured at that location so as not to affect the measurement of the particle size distribution.

[0006] Here, there is a need to provide one imaging unit for the cell through which the sample is flowing in order to observe the state of the particles that are actually the subject of particle size distribution measurement. However, if only one imaging unit is provided for the cell, it is difficult to perform various analyses based on the images, such as capturing an image of the sample and performing image analysis or detecting cell contamination. Therefore, to enable such various analyses, it is conceivable to provide a first imaging unit and a second imaging unit that are different from each other for the cell through which the sample is flowing. However, in conventional particle size distribution measurement devices, the provision of the first imaging unit and the second imaging unit may affect the detection of diffracted light and / or scattered light by the detector.

[0007] The present invention has been made in view of the above-mentioned problems, and has as its main object to provide a particle size distribution measuring device in which a first image capturing unit and a second image capturing unit that are different from each other can capture images of a sample in a cell without affecting the detection of diffracted light and / or scattered light by a detector.

[0008] That is, the particle size distribution measuring device of the present invention is a laser diffraction / scattering type particle size distribution measuring device that measures the particle size distribution of particles contained in a sample based on diffracted light and / or scattered light generated by irradiating a sample with laser light, and is characterized in that it includes a cell in which the sample is circulated and / or contained, a light irradiation unit that irradiates light onto the sample in the cell, a detector that detects the diffracted light and / or scattered light generated from the sample as a result of the light irradiation by the light irradiating unit, and a first imaging unit and a second imaging unit that image the sample in the cell, and is characterized in that an angle formed by a normal to an imaging surface of the cell and an imaging axis of the first imaging unit is different from an angle formed by a normal to the imaging surface and the imaging axis of the second imaging unit.

[0009] With this configuration, the angle between the normal to the imaging surface of the cell and the imaging axis of the first imaging unit is different from the angle between the normal to the imaging surface of the cell and the imaging axis of the second imaging unit, so that the first imaging unit and the second imaging unit can image the sample in the cell without affecting the detection of diffracted light and / or scattered light by the detector. Therefore, since different first imaging units and second imaging units can be arranged in the particle size distribution measuring device, various analyses can be performed based on the images, such as image analysis of the sample in the cell or detecting contamination of the cell.

[0010] The second imaging unit images the sample in the cell at a magnification lower than that of the first imaging unit, and it is preferable that the angle between the imaging axis of the second imaging unit and the normal to the imaging surface is larger than the angle between the imaging axis of the first imaging unit and the normal to the imaging surface.

[0011] With this configuration, the angle between the imaging axis of the second imaging unit, which has a lower magnification than the first imaging unit, and the normal to the imaging surface is larger than the angle between the imaging axis of the first imaging unit and the normal to the imaging surface, so the first imaging unit, which has a higher magnification, can capture images with less distortion than the second imaging unit, which has a lower magnification.

[0012] The cell is preferably tilted around a predetermined axis so that the normal to the imaging surface forms a predetermined angle with respect to the optical axis of the light irradiation unit.

[0013] With this configuration, the cell is inclined around a predetermined axis so that the normal to the imaging surface forms a predetermined angle with respect to the optical axis of the light irradiation unit, thereby preventing light from the light irradiation unit from reflecting on the imaging surface.

[0014] The imaging axis of the first imaging unit is preferably perpendicular to the predetermined axis.

[0015] With this configuration, the imaging axis of the first imaging unit is perpendicular to the rotation axis of the cell, whose normal to the imaging surface is rotated at a predetermined angle relative to the optical axis of the light irradiation unit, so the first imaging unit can capture images with less distortion compared to when the imaging axis of the first imaging unit is inclined relative to the rotation axis of the cell.

[0016] The normal to the imaging surface is inclined with respect to the optical axis of the light irradiation unit, and the first imaging unit and the second imaging unit are arranged on the side where the normal to the imaging surface is inclined with respect to the optical axis of the light irradiation unit.

[0017] With this configuration, the first imaging unit and the second imaging unit are arranged on the side where the normal to the imaging surface is inclined with respect to the optical axis of the light irradiation unit, so the first imaging unit and the second imaging unit can capture images with less distortion compared to when the first imaging unit and the second imaging unit are arranged on the opposite side from the side where the normal to the imaging surface is inclined with respect to the optical axis of the light irradiation unit.

[0018] The particle size distribution measuring device may further include a first imaging light irradiating unit that irradiates the cell with light when the first imaging unit images the sample in the cell, and a second imaging light irradiating unit that irradiates the cell with light when the second imaging unit images the sample in the cell.

[0019] With this configuration, the first imaging light irradiator and the second imaging light irradiator are provided corresponding to the first imaging unit and the second imaging unit, respectively, so that the amount of light when the first imaging unit images the sample and the amount of light when the second imaging unit images the sample can be maintained, compared to when the irradiator of the first imaging unit and the irradiator of the second imaging unit are common. Furthermore, because the first imaging light irradiator and the second imaging light irradiator are provided for each of the first imaging unit and the second imaging unit, it is possible to irradiate the first imaging unit and the second imaging unit with parallel light even when the imaging axis of the first imaging unit and the imaging axis of the second imaging unit are different.

[0020] It is preferable that the first imaging light irradiator and the second imaging light irradiator irradiate the cell with light via a common lens.

[0021] With this configuration, the first imaging light irradiator and the second imaging light irradiator irradiate the cell with light through a common lens, thereby reducing the number of components. Furthermore, because the first imaging light irradiator and the second imaging light irradiator irradiate the cell with light through a common lens, the first imaging light irradiator and the second imaging light irradiator can be disposed close to each other, and the first imaging unit and the second imaging unit can be disposed close to each other. As a result, misalignment between the imaging axes of the first imaging unit and the second imaging unit can be suppressed.

[0022] A specific embodiment of the lens is a Fresnel lens.

[0023] It is preferable that the imaging axis of the first imaging unit is arranged on the optical axis of the lens, the imaging axis of the second imaging unit is arranged at a position offset from the optical axis of the lens, the first imaging light irradiating unit irradiates light onto the center of the lens along the optical axis of the lens, and the second imaging light irradiating unit irradiates light onto a position offset from the center of the lens.

[0024] With this configuration, the first imaging light irradiator irradiates the center of the lens along the optical axis of the lens, so that the light is concentrated and irradiated to a portion of the cell, allowing the first imaging unit to clearly image the sample at high magnification, whereas the second imaging light irradiator irradiates light at a position off-center of the lens, so that the light is irradiated over a wide area of ​​the cell, allowing the second imaging unit to image the sample over a wide area of ​​the cell.

[0025] The second imaging unit is preferably disposed above the first imaging unit.

[0026] With this configuration, it is possible to effectively utilize the dead space within the device.

[0027] A particle size distribution measurement method in a laser diffraction / scattering particle size distribution measurement device that measures the particle size distribution of particles contained in a sample based on diffracted light and / or scattered light generated by irradiating the sample with laser light, wherein the particle size distribution measurement device includes a cell in which the sample is circulated and / or contained, and a first imaging unit and a second imaging unit that image the sample in the cell, and is characterized in that the first imaging unit and the second imaging unit are arranged so that an angle formed between a normal to an imaging surface of the cell and an imaging axis of the first imaging unit is different from an angle formed between a normal to the imaging surface and the imaging axis of the second imaging unit, and the cell is irradiated with light, and the diffracted light and / or scattered light generated from the sample is detected. A method for arranging an imaging unit in a laser diffraction / scattering particle size distribution measuring device that measures the particle size distribution of particles contained in a sample based on diffracted light and / or scattered light generated by irradiating a laser light onto the sample, the particle size distribution measuring device including: a cell in which the sample is circulated and / or contained; a light irradiation unit that irradiates light onto the cell; a detector that detects the diffracted light and / or scattered light generated from the sample as a result of the light irradiation by the light irradiating unit; and a first imaging unit and a second imaging unit that image the sample in the cell, and the method for arranging the first imaging unit and the second imaging unit may include arranging the first imaging unit and the second imaging unit so that an angle formed between a normal to an imaging surface of the cell and an imaging axis of the first imaging unit is different from an angle formed between a normal to the imaging surface and the imaging axis of the second imaging unit.

[0028] With this configuration, it is possible to obtain the same effects as those of the particle size distribution measuring device described above.

[0029] According to the present invention, it is possible to provide a particle size distribution measuring device in which a first imaging unit and a second imaging unit, which are different from each other, can capture images of a sample in a cell without affecting the detection of diffracted light and / or scattered light by a detector.

[0030] Fig. 1 is a schematic diagram of a particle size distribution measuring device according to one embodiment of the present invention; Fig. 2 is a diagram showing the positional relationship between a cell and an imaging unit in a side view in the same embodiment; Fig. 3 is a diagram showing the positional relationship between various devices constituting the particle size distribution measuring device in a top view in the same embodiment; Fig. 4 is a schematic diagram showing a lens in the same embodiment; Fig. 5 is a schematic diagram showing the positional relationship between the imaging unit, lens, and imaging light irradiation unit in the same embodiment; Fig. 6 is a flowchart showing a particle size distribution measuring method according to the same embodiment; Fig. 7 is a diagram showing the positional relationship between a cell and an imaging unit in a side view in another embodiment;

[0031] A particle size distribution measuring device according to one embodiment of the present invention will be described below with reference to the drawings. Note that in all of the drawings shown below, some parts may be omitted or exaggerated in schematic form for ease of understanding. Identical components will be assigned the same reference numerals, and their description will be omitted where appropriate.

[0032] <Device Configuration> The particle size distribution measuring device 100 of this embodiment is a laser diffraction / scattering type that measures the particle size distribution of particles contained in a sample based on diffracted light and / or scattered light generated by irradiating the sample with laser light. In this embodiment, the sample is, for example, a pharmaceutical product, food product, and / or a chemical industrial product. Here, the sample is composed of particles and a liquid that serves as a dispersion medium, and the particles are the object of measurement.

[0033] 1 , the particle size distribution measuring device 100 includes a cell 2 through which a sample flows, a light irradiation unit 3 that irradiates the sample in the cell 2 with laser light, a detector 4 that detects diffracted light and / or scattered light generated from the sample when the light irradiation unit 3 irradiates the sample, a first image capturing unit 51 and a second image capturing unit 52 that capture images of the sample in the cell 2, and a control device 6 that performs various controls based on the detection by the detector 4 and / or the images captured by the first image capturing unit 51 and the second image capturing unit 52. In this embodiment, the cell 2, the light irradiation unit 3, the detector 4, the first image capturing unit 51, and the second image capturing unit 52 are fixed to a base B via a support member (not shown). The configuration of each unit will be described below.

[0034] The cell 2 is a circulation-type flow cell and includes an inlet port a1 through which a sample is supplied, an outlet port a2 through which the sample is discharged, and an internal flow path (not shown) connected to the inlet port a1 and the outlet port a2 and through which the sample flows. When the sample is flowing and / or contained within the cell 2, particles contained in the sample move within the cell 2. The cell 2 is provided on the circulation flow path through which the sample circulates, and in addition to the cell 2, the circulation flow path may be provided with a circulation pump and / or a particle agitator for dispersing the particles in the liquid. Note that, in this embodiment, the cell 2 may have any shape as long as an irradiation surface S1 irradiated with laser light and an exit surface S2 from which diffracted light and / or scattered light exit are opposed to each other. In this embodiment, the cell 2 may have, for example, a roughly rectangular parallelepiped shape.

[0035] The emission surface S2 of the cell 2 here includes at least the opposing surface facing the irradiation surface S1 of the cell 2 onto which the laser light is irradiated, and may also include side surfaces S3 and S4 (see FIG. 3 ) interposed between the irradiation surface S1 and the opposing surface when diffracted light and / or scattered light is emitted from those side surfaces. Furthermore, when diffracted light and / or scattered light is emitted from the irradiation surface S1, the irradiation surface S1 may be the emission surface S2.

[0036] The light irradiator 3 irradiates the sample flowing through the internal flow path of the cell 2 with laser light that generates diffracted light and / or scattered light. Examples of the light irradiator 3 include a semiconductor laser. The light irradiator 3 may irradiate the sample with laser light via an optical member such as a lens. The light irradiator 3 may further include a light source with low light intensity, such as an LED light source, in addition to a light source with high light intensity, such as a laser light source.

[0037] The detector 4 detects the light intensity of diffracted light and / or scattered light generated by irradiation with laser light according to the spread angle. Here, as shown in Fig. 1, a plurality of detectors 4 are provided to measure the light intensity of diffracted light and / or scattered light according to the spread angle in a side view seen from the side of the cell 2. Also, as shown in Fig. 3, in a top view seen from the top surface of the cell 2, the detector 4 is provided on the optical axis L of the light irradiation unit 3. Note that, although the detectors 4 are provided in front of and behind the irradiation surface S1 of the cell 2 in Fig. 1, they may be provided either in front of or behind the irradiation surface S1 of the cell 2.

[0038] The first imaging unit 51 and the second imaging unit 52 image the sample in the cell 2. Here, the imaging surface of the cell 2 imaged by the first imaging unit 51 and the second imaging unit 52 is a surface constituting the cell 2. In this embodiment, it is the exit surface S2 of the cell 2, but it is not limited to the exit surface S2 of the cell 2 and may be any of the irradiation surface S1, side surface S3, and side surface S4 of the cell 2. In this embodiment, as shown in FIGS. 1 and 2 , in the particle size distribution measuring device 100, the imaging surface of the first imaging unit 51 and the imaging surface of the second imaging unit 52 face toward the exit surface S2 of the cell 2. In this embodiment, the cell 2 imaged by the first imaging unit 51 and the second imaging unit 52 is the same cell 2 to which the light irradiation unit 3 irradiates laser light. More specifically, the region imaged by the first imaging unit 51 on the imaging surface of the cell 2 overlaps with the region imaged by the second imaging unit 52 on the imaging surface of the cell 2.

[0039] The first and second imaging units 51 and 52 image the sample in the cell 2 while the light irradiation unit 3 is irradiating the laser light, but may also image the sample in the cell 2 while the light irradiation unit 3 is not irradiating the laser light. The first and second imaging units 51 and 52 may image not only the sample in the cell 2 but also the surfaces that make up the cell 2. The imaging surfaces of the first and second imaging units 51 and 52 may face the irradiation surface S1 of the cell 2.

[0040] The first imaging unit 51 is an imaging camera that images the sample in the cell 2 at a higher magnification than the second imaging unit 52. The image captured by the first imaging unit 51 is output to the image analysis unit 62 (described later) and is used for image analysis, which analyzes particle information, which is information indicating the state of the particles, from the image. Here, the particle information is information indicating the shape of the particles, separate from the particle size distribution of the particles, and examples of this include the particle's equivalent circle diameter, aspect ratio, and length. The image captured by the first imaging unit 51 may also be used to determine dirt and / or scratches on the cell 2.

[0041] The second imaging unit 52 is an imaging camera that images the sample in the cell 2 at a lower magnification than the first imaging unit 51. As a result, the second imaging unit 52 images a wider range of the sample in the cell 2 than the first imaging unit 51. Specifically, the area in the cell 2 imaged by the second imaging unit 52 includes the area in the cell 2 imaged by the first imaging unit 51. In this embodiment, the image captured by the second imaging unit 52 is output to the image analysis unit 62 described later and used to determine dirt and / or scratches on the cell 2, but may also be used for image analysis. Note that the second imaging unit 52 may image the sample in the same area in the cell 2 as the first imaging unit 51, or may image the sample in a different area from the first imaging unit 51.

[0042] 2 and 3 , the second imaging unit 52 is disposed above the first imaging unit 51, more specifically, directly above the first imaging unit 51. Note that the second imaging unit 52 may also be disposed below the first imaging unit 51.

[0043] Therefore, the angle formed by the normal N to the exit surface S2 of the cell 2 and the imaging axis C1 of the first imaging unit 51 is different from the angle formed by the normal N to the exit surface S2 of the cell 2 and the imaging axis C2 of the second imaging unit 52. Here, the imaging axis C1 of the first imaging unit 51 is an axis extending from the imaging surface of the first imaging unit 51 toward the exit surface S2 of the cell 2. The angle formed by the normal N to the exit surface S2 of the cell 2 and the imaging axis C1 of the first imaging unit 51 is an angle formed by the normal N to the exit surface S2 and the imaging axis C1 of the first imaging unit 51 on the exit surface S2 of the cell 2, and is 0 degrees or an acute angle.

[0044] The imaging axis C2 of the second imaging unit 52 is an axis extending from the imaging surface of the second imaging unit 52 toward the exit surface S2 of the cell 2. The angle formed by the normal N to the exit surface S2 of the cell 2 and the imaging axis C2 of the first imaging unit 51 is an angle formed by the normal N to the exit surface S2 and the imaging axis C2 of the first imaging unit 51 on the exit surface S2 of the cell 2, and is 0 degrees or an acute angle.

[0045] In this embodiment, the angle formed by the normal N to the exit surface S2 of the cell 2 and the imaging axis C2 of the second imaging unit 52 is larger than the angle formed by the normal N to the exit surface S2 of the cell 2 and the imaging axis C1 of the first imaging unit 51. Specifically, the angle formed by the normal N to the exit surface S2 of the cell 2 and the imaging axis C1 of the first imaging unit 51 is expressed by arccos(sin(90-α1)cosαβ1), and the angle formed by the normal N to the exit surface S2 of the cell 2 and the imaging axis C2 of the second imaging unit 52 is expressed by arccos(sin(90-α2)cosβ2). Here, α1 is the angle formed by the normal N of the exit surface S2 of cell 2 in a side view seen from the side of cell 2 and the imaging axis C1 of the first imaging unit 51, α2 is the angle formed by the normal N of the exit surface S2 of cell 2 in a side view seen from the side of cell 2 and the imaging axis C2 of the second imaging unit 52, β1 is the angle formed by the normal N of the exit surface S2 of cell 2 in a top view seen from the top surface of cell 2 and the imaging axis C1 of the first imaging unit 51, and β2 is the angle formed by the normal N of the exit surface S2 of cell 2 in a top view seen from the top surface of cell 2 and the imaging axis C2 of the second imaging unit 52. Furthermore, since the angle formed by the normal N to the exit surface S2 of cell 2 and the imaging axis C2 of the second imaging unit 52 is larger than the angle formed by the normal N to the exit surface S2 of cell 2 and the imaging axis C1 of the first imaging unit 51, the magnitude relationship cosα1cosβ1>cosα2cosβ2 holds.

[0046] 2 and 3, the normal N of the exit surface S2 of the cell 2 is inclined around a predetermined axis R with respect to the optical axis L of the light irradiation unit 3. As shown in Fig. 2, in a side view of the side surface S3 of the cell 2 seen along the normal N, the imaging axis C1 of the first imaging unit 51 is perpendicular to the predetermined axis R of the cell 2. As a result, the angle α1 in a side view formed by the normal N of the exit surface S2 and the imaging axis C1 of the first imaging unit 51 is 0 degrees.

[0047] 2 , in a side view seen from the side surface of the cell 2, the imaging axis C2 of the second imaging unit 52 is inclined with respect to the axis R of the cell 2. As a result, the angle α2 in a side view formed by the normal N to the exit surface S2 and the imaging axis C1 of the second imaging unit 52 is larger than 0 degrees. Therefore, the angle α2 in a side view formed by the normal N to the exit surface S2 and the imaging axis C1 of the second imaging unit 52 is larger than the angle α1 in a side view formed by the normal N to the exit surface S2 and the imaging axis C1 of the first imaging unit 51.

[0048] Furthermore, as shown in FIG. 3 , in a top view, which is a direction seen from the top surface of the cell 2, the first imaging unit 51 and the second imaging unit 52 are arranged on the side where the normal N of the exit surface S2 is inclined with respect to the optical axis L of the light irradiation unit 3. In this embodiment, in a top view, the normal N of the exit surface S2 is inclined by approximately 20 degrees with respect to the optical axis L of the light irradiation unit 3. In addition, in a top view, the imaging axis C1 of the first imaging unit 51 and the imaging axis C2 of the second imaging unit 52 are inclined with respect to the optical axis L of the light irradiation unit 3 on the same side as the side where the normal N of the exit surface S2 is inclined with respect to the optical axis L of the light irradiation unit 3. As a result, the imaging surfaces of the first imaging unit 51 and the second imaging unit 52 face toward the exit surface S2 of the cell 2. Note that the angle at which the normal N of the exit surface S2 is inclined with respect to the optical axis L of the light irradiation unit 3 is not limited to approximately 20 degrees, and may be between 0 and 30 degrees.

[0049] The imaging axis C1 of the first imaging unit 51 is inclined with respect to the normal N of the emission surface S2. In a top view, the angle β1 formed by the normal N of the emission surface S2 and the imaging axis C1 of the first imaging unit 51 is preferably 0 degrees or more and 10 degrees or less, and in this embodiment, it is 0 degrees or more and 5 degrees or less. Therefore, in a top view, the imaging axis C1 of the first imaging unit 51 is inclined at an angle of 10 degrees or more and 30 degrees or less with respect to the optical axis L of the light irradiation unit 3, and in this embodiment, it is inclined at an angle of 15 degrees or more and 25 degrees or less.

[0050] Furthermore, the imaging axis C2 of the second imaging unit 52 is inclined with respect to the normal N of the emission surface S2. In a top view, the angle β2 formed by the normal N of the emission surface S2 and the imaging axis C2 of the second imaging unit 52 is preferably 0 degrees or more and 20 degrees or less, and in this embodiment, it is 0 degrees or more and 10 degrees or less. Therefore, in a top view, the imaging axis C2 of the second imaging unit 52 is inclined at an angle of 0 degrees or more and 40 degrees or less with respect to the optical axis L of the light irradiation unit 3, and in this embodiment, it is inclined at an angle of 10 degrees or more and 30 degrees or less.

[0051] In the present embodiment, the angle β1 formed by the normal N of the exit surface S2 and the imaging axis C1 of the first imaging unit 51 is the same as the angle β2 formed by the normal N of the exit surface S2 and the imaging axis C2 of the second imaging unit 52. Note that the magnitude relationship between the angle β1 formed by the normal N of the exit surface S2 and the imaging axis C1 of the first imaging unit 51 and the angle β2 formed by the normal N of the exit surface S2 and the imaging axis C2 of the second imaging unit 52 need only be such that distortion of the image captured by the first imaging unit 51 is smaller than distortion of the image captured by the second imaging unit 52, and is not necessarily limited to being the same angle.

[0052] The control device 6 is a general-purpose or dedicated computer equipped with a CPU, a memory, an input / output interface, etc., and performs at least the function of a particle size distribution calculation unit 61 and the function of an image analysis unit 62 by causing the CPU and peripheral devices to cooperate in accordance with a predetermined program stored in a predetermined area of ​​the memory.

[0053] The particle size distribution calculation unit 61 calculates the particle size distribution of particles contained in the sample based on the light intensity signals output from the detectors 4. Specifically, the particle size distribution corresponding to the scattering pattern is calculated based on a scattering pattern indicated by the light intensity signals output from each detector 4, the scattering pattern being composed of the scattering angle and the intensity of the scattered light at that scattering angle, and a theoretical calculation formula such as the Mie scattering theory. The particle size distribution data indicating the particle size distribution calculated by the particle size distribution calculation unit 61 is stored in a predetermined memory and is also displayed on a display unit D, such as a display.

[0054] The image analysis unit 62 analyzes particle information based on the images captured by the first imaging unit 51 and the second imaging unit 52. The particle information analyzed by the image analysis unit 62 is stored in a predetermined memory and is also displayed on a display unit D, such as a display. The image analysis unit 62 may determine whether the cell 2 is dirty or damaged based on the images captured by the first imaging unit 51 and the second imaging unit 52.

[0055] Furthermore, as shown in FIG. 1 , in this embodiment, the particle size distribution measuring device 100 includes a first imaging light irradiator 71 that irradiates the cell 2 with light when the first imaging unit 51 images the sample in the cell 2, and a second imaging light irradiator 72 that irradiates the cell 2 with light when the second imaging unit 52 images the sample in the cell 2.

[0056] 3 , the first imaging light irradiator 71 is provided on the opposite side of the cell 2 from the first imaging unit 51, and in this embodiment, is provided on the same side of the cell 2 as the light irradiator 3. The first imaging light irradiator 71 is, for example, an LED. Note that the first imaging light irradiator 71 may also be provided on the same side of the cell 2 as the first imaging unit 51.

[0057] 3 , the second imaging light irradiator 72 is provided on the opposite side of the cell 2 from the second imaging unit 52, and in this embodiment, is provided on the same side of the cell 2 as the light irradiator 3. The second imaging light irradiator 72 is, for example, an LED. Note that the second imaging light irradiator 72 may also be provided on the same side of the cell 2 as the second imaging unit 52.

[0058] In this embodiment, the first imaging light irradiator 71 and the second imaging light irradiator 72 irradiate the cell 2 with light via a common lens 8. The lens 8 condenses the light from the first imaging light irradiator 71 toward the first imaging unit 51, and condenses the light from the second imaging light irradiator 72 toward the second imaging unit 52.

[0059] In this embodiment, the lens 8 is, for example, a Fresnel lens, as shown in FIG. 4 . Specifically, as shown in FIG. 4 , the lens 8 is obtained by cutting a circular Fresnel lens having a plurality of concentric grooves formed on its surface into a rectangular plate shape that includes the center of the concentric circles. In FIG. 4 , the solid line indicates the lens 8 cut into a rectangular plate shape, and the dashed line indicates the circular Fresnel lens before being cut into a rectangular plate shape. In the lens 8 cut into a rectangular plate shape, the center of the lens 8 is a point on the surface of the lens 8 that is normal to the surface of the lens 8 and passes through the focal point of the lens 8. For example, the center of the lens 8 is the center of the concentric circles in the circular Fresnel lens before being cut into a rectangular plate shape. Here, the center of the lens 8 is located closer to the periphery than the center of the rectangular plate shape. Note that the lens 8 has, for example, a rectangular plate shape, but the shape of the lens 8 is not limited to a rectangular plate shape.

[0060] 5 , the imaging axis C1 of the first imaging unit 51 is disposed on the optical axis of the lens 8, and the imaging axis C2 of the second imaging unit 52 is disposed at a position deviated from the optical axis of the lens 8. The optical axis of the lens 8 here refers to a normal line passing through the center of the lens 8.

[0061] 5 , the first imaging light irradiation unit 71 irradiates the center of the lens 8 with light along the optical axis of the lens 8. As a result, the light is emitted from the lens 8 so that the light from the lens 8 is collected within the cell 2, and is irradiated in a concentrated manner onto a portion of the sample in the cell 2.

[0062] 5, the second imaging light irradiator 72 irradiates light at a position off the center of the concentric circles, whereby the light transmitted through the lens 8 becomes parallel light, and the light is irradiated onto a wide range of the sample in the cell 2.

[0063] <Particle Size Distribution Measuring Method> Next, a particle size distribution measuring method using the particle size distribution measuring device 100 of this embodiment will be described.

[0064] First, the first imaging unit 51 and the second imaging unit 52 are positioned so that the angle formed by the normal N of the exit surface S2 and the imaging axis C1 of the first imaging unit 51 is different from the angle formed by the normal N of the exit surface S2 and the imaging axis C2 of the second imaging unit 52 (P1).

[0065] Next, the sample is introduced into the cell 2 (P2), whereby the sample flows through the internal flow path of the cell 2.

[0066] Then, the light irradiating unit 3 irradiates the sample with laser light. This causes diffracted light and / or scattered light from the sample, and measurement of the particle size distribution of the particles begins (P3). While the particle size distribution of the particles is being measured, the detector 4 detects the diffracted light and / or scattered light from the sample, and the particle size distribution calculating unit 61 calculates the particle size distribution of the particles based on the light intensity signal output by the detector 4.

[0067] When particle size distribution measurement of particles is started, the first imaging unit 51 and the second imaging unit 52 image the sample in the cell 2 (P4). While the first imaging unit 51 and the second imaging unit 52 image the sample in the cell 2, the light irradiator 3, the first imaging light irradiator 71, and the second imaging light irradiator 72 irradiate the sample in the cell 2 with light. As a result, the imaging of the sample in the cell 2 by the first imaging unit 51 and the second imaging unit 52 and the irradiation of the sample in the cell 2 with light by the light irradiator 3 are performed substantially simultaneously.

[0068] When the first and second image capturing units 51 and 52 capture images of the sample in the cell 2, the image analyzing unit 62 analyzes particle information based on the captured images (P5). At this time, the image analyzing unit 62 may determine whether the cell 2 is dirty and / or damaged.

[0069] When the image analysis unit 62 analyzes the particle information, if the particle size distribution measurement is to be continued, the process returns to S2, and if the measurement of the particle size distribution is to be ended, the irradiation of the laser light by the light irradiation unit 3 is ended.

[0070] Effect of the Present Embodiment According to the particle size distribution measuring device 100 of the present embodiment, the angle formed by the normal N to the exit surface S2, which is the imaging surface of the cell 2, and the imaging axis C1 of the first imaging unit 51 is different from the angle formed by the normal N to the exit surface S2, which is the imaging surface of the cell 2, and the imaging axis C2 of the second imaging unit 52. Therefore, the first imaging unit 51 and the second imaging unit 52 can image the sample in the cell 2 without affecting the detection of diffracted light and / or scattered light by the detector 4. Therefore, in the particle size distribution measuring device 100, the first imaging unit 51 and the second imaging unit 52 can be arranged differently from each other, and various analyses can be performed based on the images, such as image analysis of the sample in the cell 2 and detection of contamination on the cell 2.

[0071] Other Embodiments The present invention is not limited to the above-described embodiments.

[0072] In the above embodiment, the particle size distribution measuring method using the particle size distribution measuring apparatus 100 performs image analysis while measuring the particle size distribution. However, the image analysis may be performed before or after measuring the particle size distribution.

[0073] In the above embodiment, the particle size distribution measuring device 100 is a wet type that measures the particle size distribution of particles contained in a liquid dispersion medium, but it may also be a dry type that measures the particle size distribution of particles contained in a gaseous dispersion medium.

[0074] In the above embodiment, the cell 2 is a circulation-type flow cell in which a sample flows through an internal flow path. However, the cell 2 may be a batch-type cell having an internal space in which a sample is accommodated. When a sample is accommodated in the cell 2, particles move within the cell 2. Specifically, when a sample is accommodated in the cell 2, particles move within the cell 2 due to natural settling, stirring, for example, with a magnetic stirrer, and / or Brownian motion of the particles. Note that, because the movement of particles due to natural settling is slower than that in the case of a flow cell, the interval at which the first imaging unit 51 captures images of the cell 2 may be adjusted. Other examples of the cell 2 include a discharge-type cell in which the sample is discharged after measurement, an online-type cell, an in-line-type cell, and / or an offline-type cell.

[0075] In the above embodiment, the first imaging unit 51 is a high-magnification camera and the second imaging unit 52 is a low-magnification camera, but this is not limiting. For example, the first imaging unit 51 may be a low-magnification camera and the second imaging unit 52 may be a high-magnification camera, or both the first imaging unit 51 and the second imaging unit 52 may be low-magnification cameras, or both the first imaging unit 51 and the second imaging unit 52 may be high-magnification cameras.

[0076] In the above embodiment, the angle formed by the normal N to the exit surface S2 of the cell 2 and the imaging axis C2 of the second imaging unit 52 is larger than the angle formed by the normal N to the exit surface S2 of the cell 2 and the imaging axis C1 of the first imaging unit 51, but this is not limited to this. The angle formed by the normal N to the exit surface S2 of the cell 2 and the imaging axis C2 of the second imaging unit 52 may be smaller than the angle formed by the normal N to the exit surface S2 of the cell 2 and the imaging axis C1 of the first imaging unit 51.

[0077] In the above embodiment, the imaging axis C1 of the first imaging unit 51 is perpendicular to the predetermined axis R of the cell 2 when viewed from the side. However, it may be inclined with respect to the predetermined axis R of the cell 2.

[0078] In the above embodiment, the first image capturing unit 51 and the second image capturing unit 52 are arranged on the side where the normal N of the exit surface S2 is inclined with respect to the optical axis L of the light irradiator 3 when viewed from above, but this is not limited to this. When viewed from above, the first image capturing unit 51 and the second image capturing unit 52 may be arranged on the side opposite to the side where the normal N of the exit surface S2 is inclined with respect to the optical axis L of the light irradiator 3.

[0079] In the above embodiment, the first imaging unit 51 and the second imaging unit 52 may be configured to have adjustable focal depths. For example, the focal depths of the first imaging unit 51 and the second imaging unit 52 may be adjustable depending on whether an image is captured for image analysis or for determining whether the cell 2 is dirty and / or damaged.

[0080] In the above embodiment, a first imaging light irradiation unit 71 and a second imaging light irradiation unit 72 were provided corresponding to the first imaging unit 51 and the second imaging unit 52, respectively, but a common light irradiation unit may be provided for the first imaging unit 51 and the second imaging unit 52.

[0081] In the above embodiment, the first imaging light irradiation unit 71 and the second imaging light irradiation unit 72 irradiate light through a common lens 8, but lenses corresponding to the first imaging light irradiation unit 71 and the second imaging light irradiation unit 72 may be provided, respectively.

[0082] In the above embodiment, the exit surface S2 of the cell 2 is a flat surface, but is not limited thereto and may be a curved surface or a surface having an uneven shape. When the exit surface S2 of the cell 2 is a curved surface or a surface having an uneven shape, the normal N of the exit surface S2 of the cell 2 may be set to correspond to each of the imaging axis C1 of the first imaging unit 51 and the imaging axis C2 of the second imaging unit 52.

[0083] 7, when the exit surface S2 of the cell 2 is a curved surface, the normal N of the cell 2 has a first normal N1 corresponding to the imaging axis C1 of the first imaging unit 51 and a second normal N2 corresponding to the imaging axis C2 of the second imaging unit 52. In this case, it is only necessary that the angle α1 formed between the first normal N1 and the imaging axis C1 of the first imaging unit 51 and the angle α2 formed between the second normal N2 and the imaging axis C2 of the second imaging unit 52 are different.

[0084] In the above embodiment, the particle size distribution measuring device 100 includes the first imaging light irradiator 71, the second imaging light irradiator 72, and the lens 8, but it is not necessary to include the first imaging light irradiator 71, the second imaging light irradiator 72, and the lens 8. That is, the particle size distribution measuring device 100 is required to include at least the cell 2, the light irradiator 3, the detector 4, the first imaging unit 51, and the second imaging unit 52.

[0085] In addition, the present invention can be modified in various ways without departing from the spirit of the invention.

[0086] According to the present invention, it is possible to provide a particle size distribution measuring device in which a first imaging unit and a second imaging unit, which are different from each other, can capture images of a sample in a cell without affecting the detection of diffracted light and / or scattered light by a detector.

[0087] DESCRIPTION OF SYMBOLS 100: Particle size distribution measuring device 2: Cell 3: Light irradiation unit 4: Detector 51: First imaging unit 52: Second imaging unit 6: Control device 61: Particle size distribution calculation unit 62: Image analysis unit 71: First imaging light irradiation unit 72: Second imaging light irradiation unit 8: Lens S2: Exit surface N: Normal to the exit surface C1: Imaging axis of the first imaging unit C2: Imaging axis of the second imaging unit R: Rotation axis of the cell L: Optical axis of the light irradiation unit

Claims

1. A laser diffraction / scattering particle size distribution measuring device that measures the particle size distribution of particles contained in a sample based on diffracted light and / or scattered light generated by irradiating the sample with laser light, comprising: a cell in which the sample is circulated and / or contained; a light irradiation unit that irradiates light onto the sample in the cell; a detector that detects the diffracted light and / or scattered light generated from the sample as a result of the light irradiation by the light irradiation unit; and a first imaging unit and a second imaging unit that image the sample in the cell, wherein the angle formed by the normal to the imaging surface of the cell and the imaging axis of the first imaging unit is different from the angle formed by the normal to the imaging surface and the imaging axis of the second imaging unit.

2. The particle size distribution measuring device according to claim 1, wherein the second imaging unit images the sample in the cell at a magnification lower than that of the first imaging unit, and the angle formed between the imaging axis of the second imaging unit and the normal to the imaging surface is larger than the angle formed between the imaging axis of the first imaging unit and the normal to the imaging surface.

3. A particle size distribution measuring device according to claim 1 or 2, wherein the cell is tilted around a predetermined axis so that the normal to the imaging surface forms a predetermined angle with respect to the optical axis of the light irradiation unit.

4. The particle size distribution measuring device according to claim 3, wherein the imaging axis of the first imaging unit is perpendicular to the predetermined axis.

5. A particle size distribution measuring device according to any one of claims 1 to 4, wherein the normal to the imaging surface is inclined with respect to the optical axis of the light irradiation unit, and the first imaging unit and the second imaging unit are arranged on the side where the normal to the imaging surface is inclined with respect to the optical axis of the light irradiation unit.

6. A particle size distribution measuring device according to any one of claims 1 to 5, further comprising: a first imaging light irradiating unit that irradiates the cell with light when the first imaging unit images the sample in the cell; and a second imaging light irradiating unit that irradiates the cell with light when the second imaging unit images the sample in the cell.

7. The particle size distribution measuring device according to claim 6, wherein the first imaging light irradiating section and the second imaging light irradiating section irradiate the cell with light via a common lens.

8. The particle size distribution measuring device according to claim 7, wherein the lens is a Fresnel lens.

9. A particle size distribution measuring device according to claim 7 or 8, which cites claim 2, wherein the imaging axis of the first imaging unit is arranged on the optical axis of the lens, and the imaging axis of the second imaging unit is arranged at a position offset from the optical axis of the lens, the first imaging light irradiating unit irradiates light onto the center of the lens along the optical axis of the lens, and the second imaging light irradiating unit irradiates light onto a position offset from the center of the lens.

10. A particle size distribution measuring device according to any one of claims 1 to 9, wherein the second imaging unit is disposed above the first imaging unit.

11. A particle size distribution measurement method in a laser diffraction / scattering particle size distribution measurement device that measures the particle size distribution of particles contained in a sample based on diffracted light and / or scattered light generated by irradiating the sample with laser light, wherein the particle size distribution measurement device comprises: a cell in which the sample is circulated and / or contained; and a first imaging unit and a second imaging unit that image the sample in the cell; the first imaging unit and the second imaging unit are arranged so that the angle formed by the normal to the imaging surface of the cell and the imaging axis of the first imaging unit is different from the angle formed by the normal to the imaging surface and the imaging axis of the second imaging unit; the cell is irradiated with light; and the diffracted light and / or scattered light generated from the sample is detected.

12. A method for arranging an imaging unit in a laser diffraction / scattering particle size distribution measuring device that measures the particle size distribution of particles contained in a sample based on diffracted light and / or scattered light generated by irradiating the sample with laser light, wherein the particle size distribution measuring device comprises: a cell in which the sample is circulated and / or contained; a light irradiation unit that irradiates light onto the cell; a detector that detects the diffracted light and / or scattered light generated from the sample by the light irradiation unit; and first and second imaging units that image the sample in the cell, wherein the method for arranging the first and second imaging units arranges the first and second imaging units so that the angle formed by the normal to the imaging surface of the cell and the imaging axis of the first imaging unit is different from the angle formed by the normal to the imaging surface and the imaging axis of the second imaging unit.

Images