JP7187874B2 - light scattering detector - Google Patents

Description

The present invention relates to a light scattering detection device used in a particle detection device for measuring the molecular weight, radius of gyration (size), etc. of fine particles dispersed in a liquid sample.

Size exclusion chromatography (SEC) and gel filtration chromatography (GPC) are known as techniques for separating fine particles such as proteins dispersed in a liquid sample. In recent years, in addition to ultraviolet (UV) absorbance detectors and differential refractive index detectors, multi-angle light scattering (MALS) detectors have been used as chromatography detectors. The MALS detector has the advantage of being able to calculate the molecular weight and particle size of a sample to be measured (see Patent Documents 1 and 2).

FIG. 11 shows a coordinate system of the scattered light emitting direction when the scattered light generating light source is arranged at the origin. As shown in FIG. 11, light is incident on the XY plane in the positive direction in the X direction.

Next, FIG. 12 shows a plan view of an example of the basic configuration of the MALS detection device, and FIG. 13 shows a side view. 12 and 13, 110 is a sample cell, 111 is a liquid sample, 120 is a light source, 121 is a condenser lens, 140 is a slit plate, 150 is an imaging lens, 160 is an aperture plate, 170 is a detector, and 180 is a detector. It is a lens barrel.

As shown in FIGS. 12 and 13, a liquid sample 111 is passed through a cylindrical sample cell 110, and light is emitted from a light source 120 so as to pass through the sample cell 110 and the center of the channel. Visible laser light is usually used as the light source. The angle θ from the traveling direction of the light is defined as the scattering angle on the horizontal plane (on the XY plane), and the detectors on the horizontal plane (on the XY plane) passing through the sample cell 110 and the center of the flow channel to detect different scattering angles. 170 are arranged. FIG. 12 shows an example in which two detectors 170 are arranged at the arrangement angles of θ1 and θ2.

In the case of the cylindrical sample cell 110, there is a problem that reflected light from the interface between the glass and the air and the interface between the glass and the flow path enters the detector 170 as stray light, degrading the detection accuracy of the detector 170. . As a solution, the inventor found a method of reducing the stray light by tilting (angle α) the incident light with respect to the sample cell 110 as shown in FIG. 13 (see Non-Patent Document 1). .

In addition, it is desirable that the MALS detector be capable of measuring low-concentration samples and have a high S/N ratio. For that purpose, an optical system is required that allows the scattered light generated from the sample to efficiently enter the detector. In other words, the solid angle of scattered light entering each detector should be large. When increasing the solid angle of the detector, if the solid angle in the horizontal direction (on the optical axis plane) is increased, the angular resolution of each detector deteriorates, so it is desirable to increase the solid angle in the vertical direction. . However, increasing the detector size to increase the solid angle is not preferable because it increases the dark current.

In order to obtain a large solid angle without increasing the size of the detector, a method of condensing the scattered light with a lens or the like is adopted (Non-Patent Document 1). Specifically, it is an arrangement in which the scattered light generated in the cell channel forms an image on the detector via the imaging lens. Therefore, in order to reduce the horizontal solid angle and increase the vertical solid angle, a slit having a narrow horizontal aperture width and a wide vertical aperture length is provided on the incident side of the imaging lens. . As a result, scattered light can be efficiently detected without deteriorating the angular resolution.

JP-A-07-72068, JP 2015-111163 A "Analysis of Absolute Molecular Weights and Complex Formation of Proteins by Light Scattering Method", Masafumi Odaka, Biotechnology Vol.89

As shown in FIGS. 12 and 13, the space between the slit plate 140 and the detector 170 is usually covered with a lens barrel 180. As shown in FIGS. The lens barrel 180 is provided for the purpose of preventing light from the outside from entering the detector 170 and imaging the scattered light from the sample cell 110 onto the detector 170 .

However, as shown in FIG. 14, reflected light or transmitted light at the sample cell 110 may be reflected on the inner surface of the lens barrel 180 and enter the detector 170 as stray light. The intensity of the reflected light or transmitted light at the sample cell 110 is stronger than the scattered light (signal light) from the sample. A plurality of detectors are arranged at regular intervals around the sample cell 110 . The magnitude of the stray light depends on the placement angle of the detector 170, and is significantly greater for detectors 170 placed at low scattering angles. Due to this stray light, the dynamic range of the detector 170 is lowered, and the detection accuracy of the detector 170 is deteriorated due to intensity fluctuations of the stray light.

Accordingly, it is an object of the present invention to provide a light scattering detector that prevents stray light reflected on the inner surface of a lens barrel from entering a detector, improves the dynamic range of the detector, and enables measurement with high detection accuracy. aim.

A light scattering detection device according to an aspect of the present invention is a light scattering detection device for detecting fine particles in a liquid sample, comprising a transparent sample cell holding the liquid sample and irradiating the sample cell with coherent light. an imaging optical system for condensing light scattered from the sample cell with different scattering angles to the surroundings; and a slit plate disposed on the incident side of the imaging optical system for limiting the range of scattering angles. , a detector for receiving condensed light from the imaging optical system, an aperture plate arranged closer to the detector than the focal length of the imaging optical system, and between the slit plate and the aperture plate; and a lens barrel covering the optical path, and a reflected light removing means for removing light reflected on the inner peripheral surface of the lens barrel is provided in the lens barrel.

In the structure of the light scattering detection device, the reflected light removing means is interposed between the imaging optical system and the aperture plate in the lens barrel, and is an intra-lens barrel aperture plate for limiting reflected light. is preferably

Further, the reflected light removing means may be a reflected light shielding wall having an opening interposed between the imaging optical system in the lens barrel and the detector front aperture plate.

Further, the reflected light removing means may be a reflected light escape hole formed between the imaging optical system in the lens barrel and the detector front aperture plate.

In the reflected light removing means, a part of the inner peripheral wall of the lens barrel may be formed as a non-specular surface capable of absorbing the reflected light.

Further, a plurality of detection optical systems extending from the sample cell to the detector are arranged around the sample cell at equal intervals from the central axis of the sample cell. A pre-detector aperture plate is provided for limiting the light-receiving width to the detector by an aperture width, and the aperture width of each pre-detector aperture plate is different according to the arrangement angle of each detector with respect to the sample cell. preferable.

The aperture width of each aperture plate is preferably set by multiplying the distance from the central axis of the sample cell to the detector by the sine value of the arrangement angle of each detector.

In addition, the light source is preferably arranged such that the optical axis of coherent light incident on the sample cell from the light source is tilted at a predetermined angle from a plane containing the sample cell and the detector.

According to the present invention, it is possible to provide a light scattering detector capable of preventing stray light reflected on the inner surface of a lens barrel from entering a detector, improving the dynamic range of the detector, and measuring with high detection accuracy. can.

1 is a side view of a first embodiment of a light scattering detection device according to the present invention; FIG. 1 is a partially enlarged side view of a light scattering detection device according to a first embodiment; FIG. 1 is a plan view of a light scattering detection device according to a first embodiment; FIG. FIG. 5 is a side view for explaining a ray tracing simulation result in the first embodiment; FIG. 11 is a partially enlarged side view of the light scattering detection device according to the second embodiment; FIG. 11 is a partially enlarged side view of a modification of the light scattering detection device according to the second embodiment; FIG. 11 is a partially enlarged side view of a light scattering detection device according to a third embodiment; FIG. 11 is a partially enlarged side view of a modification of the light scattering detection device according to the third embodiment; FIG. 11 is a partially enlarged side view of a light scattering detection device according to a fourth embodiment; FIG. 11 is a plan view of a light scattering detection device according to a fifth embodiment; It is a coordinate system of the scattered light radiation direction when the scattered light generating light source is arranged at the origin. 1 is a plan view of a basic configuration example of a MALS detection device; FIG. 1 is a side view of a basic configuration example of a MALS detection device; FIG. It is a side view for demonstrating the ray tracing simulation result of a conventional structure.

First to fifth embodiments of the light scattering detector according to the present invention will be described below with reference to the drawings. It should be noted that, in each figure, the same reference numerals have the same or similar configurations.

[First embodiment]
[Configuration of Light Scattering Detector]
First, with reference to FIGS. 1 to 3, the configuration of the first embodiment of the light scattering detector according to the present invention will be described. FIG. 1 is a side view of the first embodiment of the light scattering detector according to the invention. FIG. 2 is a partially enlarged side view of the light scattering detector according to the first embodiment. As shown in FIGS. 1 and 2, the light scattering detection device 1 according to the first embodiment is a device for detecting the molecular weight and the radius of gyration (size) of fine particles such as proteins dispersed in a liquid sample. The light scattering detector 1 includes a sample cell 10 , a light source 20 , a slit plate 40 , an imaging optical system 50 , an aperture plate 60 , a detector 70 and a lens barrel 80 . Each component will be described below.

The sample cell 10 is a transparent cylindrical cell that holds a liquid sample in an internal channel. The sample cell 10 is made of, for example, colorless and transparent quartz glass.

The light source 20 irradiates the sample cell 10 with coherent light. "Coherent light" means that the phase relationship between light waves at any two points in a beam is kept constant over time. Light that exhibits perfect coherence even when combined. As the light source 20, for example, a laser light source for irradiating a visible light laser is employed. Perfectly coherent light does not exist in the natural world, and laser light oscillating in a single mode is light close to a coherent state.

A condensing optical system 21 is arranged on the optical path L<b>1 of incident light from the light source 20 to the sample cell 10 . As the condensing optical system 21, for example, a single condensing lens is employed. This condensing lens is a plano-convex lens, and has a convex surface on the incident side of the light from the light source 20 and a flat surface on the exit side. In this embodiment, a single condensing lens is used as the condensing optical system 21, but the condensing optical system 21 may be configured by combining a plurality of compound lenses or condensing mirrors.

The light source 20 and the light collecting optical system 21 are configured so that the optical axis of the coherent light incident on the sample cell 10 from the light source 20 is at a predetermined angle (tilt angle α) from the plane (XY plane) including the sample cell 10 and the detector 50. arranged to be slanted. Specifically, the light source 20 and the condensing optical system 21 are arranged so that the incident light enters the sample cell 10 obliquely from above. By tilting the incident light with respect to the sample cell 10 (angle α), the interface between the glass and the air of the sample cell 10 and the interface between the glass and the channel (hereinafter collectively referred to as "cell interface") Stray light due to reflected light can be reduced. The laser light emitted from the light source 20 is condensed near the central axis of the sample cell 10 after passing through the condensing optical system 21 .

A detection optical system 30 is arranged on the optical path L2 of the light emitted from the sample cell 10 . The detection optical system 30 of this embodiment comprises a slit plate 40 , an imaging optical system 50 , an aperture plate 60 , a lens barrel 80 and a detector 70 .

Imaging optics 50 collect light scattered from the sample cell 10 into the environment with different scattering angles. As the imaging optical system 50, for example, a single imaging lens is employed. This imaging lens is a plano-convex lens, and has a flat surface on the incident side of the scattered light from the sample cell 10 and a convex surface on the exit side. Although a single imaging lens is used as the imaging optical system 50 in this embodiment, the imaging optical system 50 may be configured by combining a plurality of compound lenses and imaging mirrors.

The slit plate 40 is arranged between the sample cell 10 and the imaging optical system 50 on the optical path L2 of the light emitted from the sample cell 10 . The slit plate 40 limits the range of scattering angles incident on the imaging optical system 50 . That is, the slit 41 opened in the slit plate 40 is elongated in the vertical direction so that at least the sides along the vertical direction are Straight. Specifically, the slit 41 has a vertically long rectangular shape or slot shape.

The aperture plate 60 is arranged closer to the imaging optical system than the detector 70 on the optical path L2 of the light emitted from the sample cell 10 . Aperture plate 60 has the function of limiting stray light, and its opening 61 opens in front of the light receiving surface of detector 70 .

The lens barrel 80 is a cylindrical body covering the optical path between the slit plate 40 and the aperture plate 60 .
A reflected light removing means 90 for removing light (reflected light RL ) reflected by the inner peripheral surface of the lens barrel 80 is provided in the lens barrel 80 . The reflected light removing means 90 is interposed between the imaging optical system 50 and the aperture plate 60 in the lens barrel 80 . The reflected light removing means 90 of the first embodiment is formed by an in-lens-barrel aperture plate 91 for limiting the reflected light RL. The intra-lens-barrel aperture plate 91 is formed, for example, by a ring-shaped disk having a circular hole in the center. The intra-lens-barrel aperture plate 91 is preferably interposed in a portion of the lens-barrel 80 where the reflected light RL is likely to be reflected.

Detector 70 receives light collected from imaging optics 50 . That is, the light receiving surface of the detector 70 is positioned at the focal point of the imaging optical system 50 . As the detector 70 of this embodiment, for example, a photodiode (PD) is adopted, but an array detector such as a two-dimensional CMOS may be adopted.

FIG. 3 is a plan view of one embodiment of the light scattering detection device according to the first embodiment. As shown in FIG. 3, a plurality of detection optical systems 30 extending from the sample cell 10 to the detector 70 are arranged around the sample cell 10 at equal intervals d from the cell center axis S. As shown in FIG. The angle θ from the traveling direction of light is defined as the scattering angle on the horizontal plane (on the XY plane). A plurality of detectors 70 are arranged on the horizontal plane (on the XY plane) passing through the sample cell 10 and the cell central axis S so as to detect different scattering angles. In the example of FIG. 3, two detection optical systems 30 and 31 are arranged at the arrangement angles of .theta.1 and .theta.2. Also in the detection optical systems 30 and 31, a lens barrel 80 having an intra-barrel aperture plate 91 having a structure similar to that described above is arranged.

[Action of Light Scattering Detector]
Next, operation of the light scattering detection device according to the first embodiment will be described with reference to FIGS. 1 to 4. FIG.

As shown in FIGS. 1 and 2, a liquid sample 11 is passed through a channel of a cylindrical sample cell 10 . When the passage of the liquid sample 11 is completed, visible laser light, which is coherent light, is emitted from the light source 20 through the condensing optical system 21 . The visible laser light travels along the optical path L<b>1 and enters the liquid sample in the flow path of the sample cell 10 . When a laser beam is incident on the liquid sample 11, the light strikes fine particles contained in the liquid sample 11 and scatters at a predetermined scattering angle. The scattered light emitted from the sample cell 10 passes through the slit 41 of the slit plate 40, passes through the imaging optical system 50, the in-lens barrel aperture plate 91 and the aperture plate 60, and reaches the light receiving surface of the detector 70. light is received.

When the scattered light is emitted from the sample cell 10, the light reflected at the interface between the air and the glass of the sample cell 10 and the interface between the liquid sample 11 and the glass (hereinafter collectively referred to as "cell interface") becomes stray light. The resulting stray light becomes reflected light RL reflected on the inner peripheral surface of the lens barrel 80 . Since the slit plate 40 is provided on the incident side of the imaging optical system 50, the plate portion of the slit plate 40 can limit stray light from the cell interface to some extent. An optical path L2 between the slit plate 40 and the aperture plate 60 is covered with a lens barrel 80. As shown in FIG.

When reflected light or transmitted light from the sample cell 10 enters the lens barrel 80 through the slit plate 40 and the imaging optical system 50, it is reflected on the inner peripheral surface of the lens barrel 80 and enters the detector 70 as stray light. Sometimes. The intensity of the reflected light or transmitted light at the sample cell 10 is stronger than the scattered light (signal light) from the liquid sample 11 . When a plurality of detectors 70 are provided around the sample cell 10 at equal intervals d, the magnitude of stray light varies depending on the arrangement angle θ of the detectors 70 . The detector 70 arranged at the low scattering angle .theta.1 has significantly larger stray light than the detector 70 arranged at the scattering angle .theta.2. Due to this stray light, the dynamic range of the detector 70 is lowered, and the detection accuracy of the detector 70 is deteriorated due to intensity fluctuations of the stray light.

Therefore, in the light scattering detector 1 according to the first embodiment, an intra-lens barrel aperture plate 91 for limiting the reflected light RL is provided in the barrel 80 covering the optical path L2 between the slit plate 40 and the aperture plate 60. is interposed. The intra-lens-barrel aperture plate 91 is formed of a ring-shaped disk having a circular hole in the center, and is interposed in a portion within the lens-barrel 80 where the reflected light RL is likely to be reflected. Therefore, it is possible to limit the stray light that tries to enter the detector 70 by being reflected by the inner peripheral surface of the lens barrel 80 . In addition, since the aperture plate 60 further limits stray light, scattered light necessary for analysis can be received by the light-receiving surface of the detector 70 .

[Ray tracing simulation]
A ray tracing simulation was performed to confirm the effects of the first embodiment. FIG. 4 is a side view for explaining the result of ray tracing simulation when the detector (PD) is arranged at θ=15 degrees.

As shown in FIG. 4, the sample cell 10 is, for example, a transparent cylindrical cell with an inner diameter of 1.6 mm and an outer diameter of 8.0 mm. An imaging lens (plano-convex lens) is arranged at a position 26 mm from the central axis S of the sample cell 10 . The imaging lens has a convex diameter of φ9 mm and a focal length of 18 mm, for example. At a position of 80 mm from the central axis S of the sample cell 10, an aperture plate 60 and a PD of .quadrature.5 mm are arranged. The slit 41 of the slit plate 40 has a rectangular opening in order to limit the horizontal scattering angle (.theta. direction) and widen the vertical direction (.phi. direction) (see FIG. 11).

As shown in FIG. 4 , in the lens barrel 80 , an intra-lens-barrel aperture plate 91 is interposed between the imaging optical system 50 and the aperture plate 60 . The intra-lens-barrel aperture plate 91 is provided at a position 55 mm from the central axis S of the sample cell, and has an opening of φ4 mm. By arranging the in-lens-barrel aperture plate 91 in the vicinity of the imaging position of the imaging optical system 50 in this manner, it is possible to block stray light without impairing the signal light.

As described above, according to the light scattering detector 1 according to the first embodiment, the lens barrel 80 includes the intra-barrel aperture plate 91 for limiting the reflected light RL. It is possible to prevent stray light reflected on the peripheral surface from entering the detector 70 . In addition, although the detector 70 arranged at the low scattering angle θ1 has a large amount of stray light, the stray light can be limited by the aperture plate 91 in the lens barrel. .

[Second embodiment]
Next, a light scattering detector 2 according to a second embodiment will be described with reference to FIGS. 5 and 6. FIG. FIG. 5 is a partially enlarged side view of the light scattering detector according to the second embodiment. FIG. 6 is a partially enlarged side view of a modification of the light scattering detector according to the second embodiment. In addition, what attached the code|symbol same as 1st Embodiment has the same or similar structure.

As shown in FIG. 5, in the light scattering detection device 2 according to the second embodiment, the reflected light removing means 90 is formed by a reflected light shielding wall 92 having an opening provided in the lens barrel 80. This point differs from the first embodiment. The reflected light shielding wall 92 is interposed between the imaging optical system 50 and the pre-detector aperture plate 60 . In the embodiment of FIG. 5, the reflected light shielding wall 92 is formed as a ring-shaped projecting wall having a circular hole.

The reflected light shielding wall 92 need not be formed along the entire circumference of the inner peripheral surface of the lens barrel 80, and may be formed at a portion of the inner peripheral surface of the lens barrel 80 where the reflected light RL is likely to be reflected. . In this embodiment, the light emitted from the light source 20 is incident obliquely above the sample cell 10 at the tilt angle α, so the reflected light (stray light) generated at the cell interface of the sample cell 10 tends to be deflected downward. Therefore, the reflected light and transmitted light that have passed through the slit plate 40 and the imaging optical system 50 are also likely to be biased toward the lower portion of the inner peripheral surface of the lens barrel 80 . Therefore, as shown in FIG. 6, if the reflected light shielding wall 92 is formed at least in the lower part of the inner peripheral surface of the lens barrel 80, reflected light and transmitted light can be shielded.

The light scattering detection device 2 according to the second embodiment basically has the same effects as the light scattering detection device 1 according to the first embodiment. In particular, according to the light scattering detection device 2 according to the second embodiment, the reflected light removing means 90 is formed by the reflected light shielding wall 92 having an opening provided in the lens barrel 80, so that the reflected light Forming the shielding wall 92 on a part of the inner peripheral surface of the lens barrel 80 provides an advantageous effect of expanding variations in the structural design of the reflected light shielding wall 92 .

[Third embodiment]
Next, a light scattering detector 3 according to a third embodiment will be described with reference to FIGS. 7 and 8. FIG. FIG. 7 is a partially enlarged side view of the light scattering detector according to the third embodiment. FIG. 8 is a partially enlarged side view of a modification of the light scattering detector according to the third embodiment. In addition, what attached the code|symbol same as 1st Embodiment has the same or similar structure.

As shown in FIG. 7, in the light scattering detector 3 according to the third embodiment, the reflected light removing means 90 is formed as a reflected light escape hole 93 for letting the reflected light escape from the lens barrel 80. , different from the first embodiment. The reflected light escape hole 93 is interposed between the imaging optical system 50 and the front-detector aperture plate 60 in the lens barrel 80 . It is preferable that the reflected light escape hole 93 is formed at a portion of the inner peripheral surface of the lens barrel 80 where stray light from the cell interface is likely to be reflected . The reflected light escape hole 93 in the embodiment of FIG. 7 is opened to the outside of the lens barrel 80 .

As described above, the illumination light from the light source 20 is incident on the sample cell 10 obliquely from above at the tilt angle α. It tends to deviate to the lower part of the surface. Therefore, as shown in FIG. 7, if at least the reflected light escape hole 93 is formed in the lower part of the inner peripheral surface of the lens barrel 80, the reflected light and the transmitted light can escape to the outside through the reflected light escape hole 93. can be done.

8, the lower portion of the lens barrel 80 is formed thick, and the reflected light escape hole 93 is formed as a cylindrical hole. Since the lower portion of the cylindrical hole is closed by the base, it is possible to allow reflected light and transmitted light to escape to the cylindrical reflected light escape hole 93 while preventing light from entering from the outside.

The light scattering detection device 3 according to the third embodiment has basically the same effects as the light scattering detection device 1 according to the first embodiment. In particular, according to the light scattering detection device 3 according to the third embodiment, the reflected light removing means 90 is formed as the reflected light escape hole 93 for letting the reflected light escape from the lens barrel 80. This has the advantage of allowing light to actively escape to the outside or into the cylindrical hole.

[Fourth embodiment]
Next, a light scattering detection device 4 according to a fourth embodiment will be described with reference to FIG. FIG. 9 is a partially enlarged side view of the light scattering detector according to the fourth embodiment. In addition, what attached the code|symbol same as 1st Embodiment has the same or similar structure.

As shown in FIG. 9, in the light scattering detection device 4 according to the fourth embodiment, the reflected light removing means 90 has at least a portion of the inner peripheral surface of the lens barrel formed as a non-specular surface 94 capable of absorbing the reflected light. is different from the first embodiment. The non-specular surface 94 is interposed between the imaging optical system 50 and the front detector aperture plate 60 within the lens barrel 80 . The non-specular surface 94 is preferably formed on the inner peripheral surface of the lens barrel 80 at a portion where stray light from the cell interface is likely to be reflected .

As a specific example of the non-specular surface 94, for example, a black felt sheet may be attached to a portion of the inner peripheral surface of the lens barrel 80 where reflected light is likely to occur to form a non-reflective surface. The non-specular surface 94 can also reduce stray light by partially roughening the inner peripheral surface of the lens barrel 80 by threading or the like and then blackening the surface.

The light scattering detection device 4 according to the fourth embodiment basically has the same effects as the light scattering detection device 1 according to the first embodiment. In particular, according to the light scattering detection device 4 according to the fourth embodiment, since at least a part of the inner peripheral surface of the lens barrel is formed as a non-specular surface 94 capable of absorbing the reflected light, the reflected light removing means 90 is An advantageous effect is obtained in that reflected light and transmitted light can be positively absorbed.

[Fifth embodiment]
Next, a light scattering detector 5 according to a fifth embodiment will be described with reference to FIG. FIG. 10 is a plan view of the light scattering detection device according to the fifth embodiment. In addition, what attached the code|symbol same as 1st Embodiment has the same or similar structure.

As shown in FIG. 10, the light scattering detection device 5 according to the fifth embodiment includes a front detector aperture plate 65 that limits the light receiving width to the detector 70 by the aperture width, on the detector side of the lens barrel 80. It differs from the first embodiment in that it is provided. That is, in the fifth embodiment, a front-detector aperture plate 65 is provided separately from the aperture plate 60 forming part of the lens barrel 80 .

A plurality of detection optical systems 30 extending from the sample cell 10 to the detector 70 are arranged around the sample cell 10 at equal intervals d from the central axis S of the sample cell 10 (hereinafter simply referred to as the "cell central axis"). ing. The angle θ from the traveling direction of light is defined as the scattering angle on the horizontal plane (on the XY plane). A plurality of detectors 70 are arranged on the horizontal plane (on the XY plane) passing through the sample cell 10 and the cell central axis S so as to detect different scattering angles. In the embodiment of FIG. 10, two detection optical systems 30 and 31 are arranged at the arrangement angles of θ1 and θ2.

The scattered light image formed on the light receiving surface of the detector 70 varies in size depending on the angle at which the detector is arranged. When the liquid sample 11 is uniformly distributed within the sample cell 10 , the scattered light originating from the sample is generated with a length matching the inner diameter L of the sample cell 10 . Assuming that the arrangement angle of the detector is θ and the magnification of the cell and imaging lens is M, the length of the scattered light image formed on the detector is ML sin θ.

Here, the inner diameter L of the sample cell 10 and the magnification M of the imaging lens are the same for all the detection optical systems 30, 31, . Therefore, when a plurality of detection optical systems 30 and 31 are arranged around the sample cell 10 at equal intervals d from the cell central axis S, the aperture width of each pre-detector aperture plate 65 is different from that of the sample cell 10. It is made different according to the arrangement angles θ1 and θ2 of the detector 70 . The aperture width of each pre-detector aperture plate 65 is set by multiplying the distance d from the cell center axis S to the detector 70 by the sine value of the arrangement angles θ1 and θ2 of each detector 70 . Specifically, the opening width of the pre-detector aperture plate 65 with the arrangement angle θ1 is set to the width of d sin θ1. Further, the opening width of the pre-detector aperture plate 65 with the arrangement angle θ2 is set by the width of d sin θ2.

Since the light scattering detection device 5 according to the fifth embodiment includes the constituent elements of the light scattering detection device 1 according to the first embodiment, it has basically the same effects as those of the first embodiment. In particular, according to the light scattering detection device 5 according to the fifth embodiment, the pre-detector aperture plate 65 that limits the light receiving width to the detector 70 by the aperture width is provided on the detector side of the lens barrel 80, Since the opening width of each detector front aperture plate 65 is varied according to the arrangement angles θ1 and θ2 of each detector 70 with respect to the sample cell 10, the light receiving width to the detector 70 can be set to an optimum width. It has the advantage of being able to

The above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to limit and interpret the present invention. Each element included in the embodiment and its arrangement, materials, conditions, shape, size, etc. are not limited to those illustrated and can be changed as appropriate. Also, it is possible to partially replace or combine the configurations shown in different embodiments.

Reference Signs List 1 Light scattering detector 10 Sample cell 20 Light source 30 Detection optical system 40 Slit plate 41 Slit 50 Imaging optical system 60 Aperture plate 65 Pre-detector aperture plate 70 Detector 80 Barrel 90 Reflected light removing means 91 Aperture plate in lens barrel 92 Reflected light shielding wall 93 Reflected light escape hole 94 Non-specular surface

Claims (8)

A light scattering detection device for detecting particulates in a liquid sample, comprising:
a transparent sample cell holding a liquid sample;
a light source that irradiates the sample cell with coherent light;
imaging optics for collecting light scattered from the sample cell into its surroundings with different scattering angles;
a slit plate disposed on the incident side of the imaging optical system for limiting the range of scattering angles;
a detector that receives condensed light from the imaging optical system;
an aperture plate arranged closer to the detector than the imaging optical system;
a lens barrel that covers an optical path between the slit plate and the aperture plate;
with
A light scattering detection apparatus, wherein the lens barrel includes reflected light removing means for removing light reflected on the inner peripheral surface of the lens barrel. The reflected light removal means is interposed between the imaging optical system and the aperture plate in the lens barrel, and the reflected light is formed by a ring-shaped plate which is a separate member from the lens barrel. 2. The light scattering detector according to claim 1, which is an aperture plate in the lens barrel for limiting the . The reflected light removing means is a reflected light shielding wall interposed between the imaging optical system and the aperture plate in the lens barrel and formed integrally with the lens barrel as a ring-shaped projecting wall. 2. The light scattering detection device of claim 1, wherein 2. The light scattering detector according to claim 1, wherein said reflected light removing means is a reflected light escape hole formed between said imaging optical system and said aperture plate in said lens barrel. 2. The light scattering detector according to claim 1, wherein said reflected light removing means is formed as a non- specular surface. A plurality of detection optical systems from the sample cell to the detector are arranged around the sample cell at equal intervals from the central axis of the sample cell,
A front-detector aperture plate for limiting a light-receiving width to the detector by an aperture width is provided on the detector side of the lens barrel,
6. The light scattering detector according to any one of claims 1 to 5, wherein the opening width of each pre-detector aperture plate differs according to the arrangement angle of each detector with respect to the sample cell. 7. The aperture plate according to claim 6, wherein the opening width of each pre-detector aperture plate is set by multiplying the distance from the center axis of the sample cell to the detector by the sine value of the arrangement angle of each detector. Light scattering detector. 8. The light source is arranged such that an optical axis of coherent light incident on the sample cell from the light source is inclined at a predetermined angle from a plane including the sample cell and the detector. 1. A light scattering detection device according to claim 1.

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