Light scattering measurement device

Abstract

To provide a light scattering measurement device including an optical element holder contributing to the downsizing of the light scattering measurement device.SOLUTION: A light scattering measurement device includes: a light source; a sample cell storing a sample and having light incident from the light source; a detection part for detecting emitted light emitted from the sample cell; an optical element holder 4 having the axis of rotation AR orthogonal to a plane determined by the path LP of the emitted light toward the detection part from the sample cell and for holding a plurality of optical elements including first and second optical elements 401-1 and 402-2 provided so as to face the axis of rotation around each axis of rotation; and an optical element holder support part for supporting the optical element holder so as to rotate around the axis of rotation. The optical element holder can rotate at least between a first posture having the first optical element positioned on the path and a second posture having the second optical element positioned on the path.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a light scattering measurement device. [Background technology]

[0002] In a light scattering measurement device, an optical element holder that holds an optical element that changes optical properties such as the polarization direction may be provided between the sample cell and the detection unit. For example, when the anisotropy of a measurement sample is measured using a light scattering measurement device, a polarizing element holder is provided between the sample cell and the detection unit.

[0003] When two or more types of optical elements are held in the optical element holder, it is necessary to switch between these optical elements. For example, if you want to extract and measure vertically linearly polarized components and horizontally linearly polarized components from the scattered light from a measurement sample, you need to switch between a polarizing element with a vertical polarization axis and a polarizing element with a horizontal polarization axis.

[0004] Conventionally, various optical element holders that enable mutual switching between multiple optical elements have been considered. For example, in the field of variable polarization wafer inspection, a technology is known in which the polarization direction is switched by sliding a plate-shaped holder on which multiple polarization elements are arranged in the horizontal direction (see FIG. 3 in Patent Document 1 below). Also, in the field of appearance measurement of birefringent fibers, a technology is known in which multiple polarization elements are arranged on a disk-shaped holder having a rotation axis parallel to the light path, and the polarization direction is switched by rotating this holder around the rotation axis (see FIG. 3A in Patent Document 2 below). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special table 2015-516574 [Patent Document 2] Patent Publication No. 2011-069805 Summary of the Invention [Problem to be solved by the invention]

[0006] On the other hand, the conventional optical element holder described in the above patent document requires a large space for installation. This is because the conventional optical element holder has multiple optical elements arranged on the same plane. To be more specific, the conventional optical element holder has multiple optical elements arranged on a plate-shaped or disk-shaped substrate. All of these optical elements face the same direction, that is, the same direction as the path of the light incident on the optical element holder. Here, in the optical element holder, only one of the multiple optical elements is involved in the measurement, that is, is placed on the path of the light. Of the multiple optical elements, the optical elements other than this one optical element occupy a certain space in the width direction of the substrate in the optical element holder, even though they are not involved in the measurement. As a result, a dead space is generated by the certain space.

[0007] Therefore, when the conventional optical element holder is used, the light scattering measurement device itself becomes large. In particular, when the light scattering measurement device has two or more detection units, that is, when performing measurement by the multi-angle light scattering method, two or more optical element holders are required. In this case, when the conventional optical element holder is used, the dead space increases, and the size of the measurement device becomes even more significant.

[0008] The present invention has been made in consideration of the above problems, and has an object to provide a light scattering measurement device equipped with an optical element holder that contributes to miniaturization of the light scattering measurement device. [Means for solving the problem]

[0009] (1) A light scattering measurement device according to the present invention comprises a light source, a sample cell for accommodating a sample and into which light from the light source is incident, a detection unit for detecting the outgoing light emitted from the sample cell, an optical element holder having a rotation axis perpendicular to a plane determined by a path of the outgoing light from the sample cell toward the detection unit and holding a plurality of optical elements including a first optical element and a second optical element each arranged around the rotation axis to face the rotation axis, and an optical element holder support unit for supporting the optical element holder so as to be rotatable around the rotation axis, wherein the optical element holder is rotatable at least between a first position in which the first optical element is located on the path and a second position in which the second optical element is located on the path.

[0010] (2) In the light scattering measuring device of (1), the optical element holder has a main body and holds the multiple optical elements on a side of the main body, and the side of the main body may be provided with multiple openings including a first opening opened on the opposite side of the first optical element and a second opening opened on the opposite side of the second optical element.

[0011] (3) In the light scattering measuring device of (2), the rotation axis may be located on the path and be sandwiched between the first optical element and the first opening, and also between the second optical element and the second opening.

[0012] (4) In the light scattering measurement device of (3), the plurality of optical elements and the plurality of openings may be arranged at equal angular intervals all around the rotation axis.

[0013] (5) In any one of the light scattering measurement devices (1) to (4), the optical element holder may include a polygonal portion in cross section.

[0014] (6) In the light scattering measurement device according to any one of (2) to (5), the plurality of openings may include a third opening and a fourth opening facing each other.

[0015] (7) In any one of the light scattering measurement devices (1) to (6), the first optical element and the second optical element may each be a polarizing element.

[0016] (8) In any one of the light scattering measurement devices (1) to (7), the direction of the polarization axis of the first optical element and the direction of the polarization axis of the second optical element may be different from each other.

[0017] (9) Any of the light scattering measuring devices (1) to (8) may include a plurality of detection units including a first detection unit and a second detection unit adjacent to the first detection unit, and a plurality of the optical element holders including a first optical element holder corresponding to the first detection unit and a second optical element holder corresponding to the second detection unit.

[0018] (10) Any of the light scattering measuring devices of (1) to (9) may include a first gear, a second gear that meshes with the first gear, rotates with the rotation of the first gear, and is rotatable integrally with the first optical element holder, and a third gear that meshes with the first gear, rotates with the rotation of the first gear, and is rotatable integrally with the second optical element holder. [Brief description of the drawings]

[0019] [Figure 1] 1 is a perspective view showing a light scattering measurement device according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a diagram showing a schematic planar arrangement of a light scattering measurement device according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a perspective view showing an optical element holder according to the embodiment of the present invention. [Figure 4] FIG. 2 is a side view showing an optical element holder according to the embodiment of the present invention. [Diagram 5] 5 is a longitudinal sectional view of FIG. 4 taken along a plane including a rotation axis AR. [Figure 6] 6 is a cross-sectional view of FIG. 4 taken along line VI-VI. [Figure 7]FIG. 13 is a perspective view showing a light scattering measurement device according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0021] First, an overview of a light scattering measurement device according to an embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a perspective view showing a light scattering measurement device according to an embodiment of the present invention. Figure 2 is a diagram showing a schematic planar arrangement of a light scattering measurement device according to an embodiment of the present invention.

[0022] 1 and 2, the light scattering detection apparatus 100 includes a light source 1, a sample cell 2, a plurality of detection units 3, a plurality of optical element holders 4, and an optical element holder support unit 5. The light scattering detection apparatus 100 of this embodiment is a multi-angle light scattering measurement apparatus.

[0023] The light source 1 generates light L that is irradiated onto the sample. The sample cell 2 is a transparent container that contains the sample. The light L from the light source 1 is incident on the sample cell 2 (the sample in the sample cell 2). The scattered light SL is emitted from the sample cell 2 (the sample in the sample cell 2) in multiple directions around the sample cell 2 that differ by an angle θ.

[0024] Each of the multiple detection units 3 detects the scattered light SL corresponding to that detection unit 3 among the scattered light SL emitted in the multiple directions. Therefore, each of the multiple detection units 3 is provided adjacent to each other at an angle θ with the sample cell 2 as the center on a circumference C1 surrounding the sample cell 2 (FIG. 2). The output of each of the multiple detection units 3 is transmitted to a control device (not shown). Then, the control device calculates the particle diameter and molecular weight of the substance in the sample based on the angle dependency of the intensity of the scattered light SL detected by each of the multiple detection units 3. In this embodiment, the sample is a liquid sample, but the sample may be a solid sample.

[0025] Each of the optical element holders 4 holds a first optical element 401-1 and a second optical element 401-2, as described later (see FIGS. 3 to 6). Each of the optical element holders 4 is provided between the sample cell 2 and the detector 3 corresponding to the optical element holder 4. That is, each of the optical holders 4 is provided adjacent to each other at an angle θ on a concentric circumference C2 that surrounds the sample cell 2 and is located inside the circumference C1 (FIG. 2). Each of the optical element holders 4 is rotatable between a first position in which the first optical element 401-1 is located on a path LP of the scattered light SL from the sample cell 2 toward the detector 3 corresponding to the optical element holder 4, and a second position in which the second optical element 401-2 is located on the path LP (see FIGS. 3 to 6).

[0026] In this way, each of the multiple optical element holders 4 can rotate between the first and second positions, which enables switching between measurement using the first optical element 401-1 and measurement using the second optical element 401-2 in the light scattering measurement device 100. Note that, although a case where the number of detection units 3 and optical element holders 4 is 11 each is shown in Figures 1 and 2, the number of detection units 3 and optical element holders 4 may be less or more than this.

[0027] As described above, the optical element holder support part 5 rotatably supports the multiple optical element holders 4. That is, the optical element holder support part 5 is formed of a circular ring-shaped plate material along a circumference C2, and the sample cell 2 is disposed in a hole at the center of the circular ring. Note that the shape of the optical element holder support part 5 is not limited to a circular ring shape, and may be another shape.

[0028] The optical element holder 4 will be described in detail below. First, the optical element holder 4 will be described in its entirety with reference to Figs. 3 to 5. Fig. 3 is a perspective view showing an optical element holder according to an embodiment of the present invention. Fig. 4 is a side view showing an optical element holder according to an embodiment of the present invention. Fig. 5 is a vertical cross-sectional view of Fig. 4 cut along a plane including the rotation axis AR. Note that Figs. 3 to 5 only show the path LP and a portion of the optical element holder support portion 5.

[0029] 3 to 5, the optical element holder 4 has a main body 40 and a knob 41. The main body 40 includes a lower portion 40a and an upper portion 40b.

[0030] The lower portion 40a has a hexagonal prism shape, and the upper portion 40b has a cylindrical shape (FIG. 3). The central axis of the lower portion 40a and the central axis of the upper portion 40b are aligned on the same straight line (FIG. 5), and this straight line is the rotation axis AR of the optical element holder 4. The shape of the lower portion 40a is not limited to a hexagonal prism shape, and may be other shapes such as a cylindrical shape or a hemispherical shape.

[0031] The lower end of the upper part 40b is rotatably supported by the optical element holder support part 5 via spacers 51, 51 (FIG. 5). The spacers 51, 51 are each shaped like an annular plate, with a cylindrical wall rising from the inner circumference. A plurality of holes are formed on the optical element holder support part 5 along the circumference C2, and one of the spacers 51, 51 is fitted from the upper side of each hole, and the other of the spacers 51, 51 is fitted from the lower side of each hole. A cylindrical knob 41 is non-rotatably fitted to the upper end of the upper part 40a (FIGS. 3 and 5). This allows the user to pinch the knob 41 and rotate the optical element holder 4 around the rotation axis AR. The knob 41 may have a shape other than cylindrical.

[0032] The optical element holder 4 will be described in detail below with further reference to Fig. 6. Fig. 6 is a cross-sectional view of Fig. 4 taken along line VI-VI.

[0033] The lower portion 40a is provided with a first through hole TH1 and a second through hole TH2 penetrating the opposing side surfaces (FIG. 6). A first optical element 401-1 is provided at one end of the first through hole TH1, and the other end of the first through hole TH1 is a first opening 402-1. A second optical element 401-2 is provided at one end of the second through hole TH2, and the other end of the second through hole TH2 is a second opening 402-2. The first optical element 401-1 and the first opening 402-1 face each other. Similarly, the second optical element 401-2 and the second opening 402-2 face each other.

[0034] As a result, the scattered light SL incident on the first optical element 401-1 passes through the first through hole TH1 and is emitted from the first opening 402-1, so that the detection unit 3 can detect the scattered light SL that has passed through the first optical element 401-1. Similarly, the scattered light SL incident on the second optical element 401-2 passes through the second through hole TH2 and is emitted from the second opening 402-2, so that the detection unit 3 can detect the scattered light SL that has passed through the second optical element 401-2. Note that the scattered light SL incident on the first opening 402-1 may pass through the first through hole TH1 and then pass through the first optical element 401-1. Also, the scattered light SL incident on the second opening 402-2 may pass through the second through hole TH2 and then pass through the second optical element 401-2.

[0035] Furthermore, the lower portion 40a is provided with a third through hole TH3 penetrating the opposing side surfaces (FIG. 6). One end of the third through hole TH3 is a third opening 402-3, and the other end of the third through hole TH3 is a fourth opening 402-4. The third opening 402-3 and the fourth opening 402-4 face each other. In addition, by rotating the optical element holder 4, the third opening 402-3 and the fourth opening 402-4 can be positioned on the path LP. In this way, by providing a through hole in which no optical element is provided, even when the light scattering measurement device 100 includes the optical element holder 4, it is possible to perform normal measurement without involving the first optical element 401-1 and the second optical element 401-2.

[0036] The optical element holder 4 may have four or more through holes. That is, the optical element holder 4 may hold three or more optical elements. The optical element holder 4 may have five or more openings. The arrangement of the first optical element 401-1 and the second optical element 401-2 is not limited to that shown in FIG. 6, and the first optical element 401-1 and the second optical element 401-2 may be adjacent to each other.

[0037] Although the openings such as the first opening 402-1 are circular holes (see FIG. 3, etc.), they may be changed to a shape other than a hole as long as they can function to transmit light. For example, the openings may be notches provided at the upper or lower end of the lower portion 40a.

[0038] The center line CL1 of the first through hole TH1 is perpendicular to the rotation axis AR and passes through the rotation center CR, which is the intersection of the rotation axis AR and the path LP (FIG. 6). Similarly, the center line CL2 of the second through hole TH2 is perpendicular to the rotation axis AR and passes through the rotation center CR, which is the intersection of the rotation axis AR and the path LP (FIG. 6). Furthermore, the center line CL3 of the third through hole TH3 is perpendicular to the rotation axis AR and passes through the rotation center CR, which is the intersection of the rotation axis AR and the path LP (FIG. 6). In addition, the rotation axis AR is located on the path LP and is perpendicular to the path LP (FIGS. 3 to 5).

[0039] This allows the scattered light SL to pass through the first through hole TH1, the second through hole TH2, and the third through hole TH3 when the optical element holder 4 is rotated. Note that the rotation axis AR and the path LP may intersect in a manner other than perpendicular as long as this effect is achieved. Also, the rotation axis AR and the center line CL1 of the first through hole TH1, the center line CL2 of the second through hole TH2, or the center line CL3 of the third through hole TH3 may intersect in a manner other than perpendicular as long as this effect is achieved. Furthermore, the rotation axis AR does not have to be located on the path LP, and may intersect with the path LP in a manner other than perpendicular as long as the above effect is achieved.

[0040] The first optical element 401-1 and the second optical element 401-2 are each shaped like a plate having two main surfaces. Here, the normal direction of each of the main surfaces of the first optical element 401-1 and the second optical element 401-2 (i.e., the direction of the center line CL1 of the first through hole TH1 and the direction of the center line CL2 of the second through hole TH2) is perpendicular to the rotation axis AR (FIGS. 5-6). In other words, the first optical element 401-1 and the second optical element 401-2 are provided so as to face the rotation axis AR around the rotation axis AR. That is, the multiple optical elements 401 are not provided on the same plane, and the dead space caused by the optical elements not involved in the measurement can be reduced, so that the optical element holder 4 can be made small. The main surfaces of the first optical element 401-1 and the second optical element 401-2 may be flat or curved.

[0041] Here, the first optical element 401-1 and the second optical element 401-2 are polarizing elements (polarizing plates) as an example. The direction of the polarization axis of the first optical element 401-1 is parallel to the rotation axis AR, i.e., the vertical direction, and the direction of the polarization axis of the second optical element 401-2 is perpendicular to the rotation axis AR, i.e., the horizontal direction. The direction of the polarization axis of the first optical element 41a and the direction of the polarization axis of the second optical element 41b may be set arbitrarily depending on the purpose of the measurement. In addition, various optical elements such as ND filters for adjusting the amount of light and colored glass filters for adjusting the wavelength, in addition to polarizing elements, can be selected as the first optical element 401-1 and the second optical element 401-2. For example, different types of optical elements may be used in appropriate combination, such as using one of the first optical element 401-1 and the second optical element 401-2 as a polarizing element and the other of the first optical element 401-1 and the second optical element 401-2 as an ND filter.

[0042] In the optical element holder 4 of this embodiment, the rotation axis AR is located on the path LP, and the first optical element 401-1 and the first opening 402-1 are arranged to sandwich the rotation axis AR, and the second optical element 401-2 and the second opening 402-2 are arranged to sandwich the rotation axis AR (FIGS. 5-6). With this configuration, the side surface of the lower portion 40a of the optical element holder 4 can be more effectively utilized, and therefore the optical element holder 4 can be made more compact.

[0043] Furthermore, the direction of the center line CL1 of the first through hole TH1, the direction of the center line CL2 of the second through hole TH2, and the direction of the center line CL3 of the third through hole TH2 are different from each other by 60 degrees around the rotation center CR (FIG. 6). That is, the first optical element 401-1, the third opening 402-3, the second optical element 401-2, the first opening 402-1, the fourth opening 402-4, and the second opening 402-2 are arranged at equal angular intervals all around the rotation axis AR. With this configuration, the side surface of the lower portion 40a of the optical element holder 4 can be utilized as effectively as possible, so that the optical element holder 4 can be made even smaller.

[0044] The present invention is not limited to the above embodiment, and various modifications are possible. One of the modifications of the present invention will be described below with reference to Fig. 7. Fig. 7 is a perspective view showing a light scattering measurement device according to the modification.

[0045] In this modification, the light scattering measurement device 100 further includes a large gear 6 and a plurality of small gears 7. The large gear 6 is provided on the optical element holder support portion 5, and its plurality of teeth surround the sample cell 2. In addition, the rotation axis of the large gear 6 is parallel to the rotation axes AR of the plurality of optical element holders 4.

[0046] Each of the multiple small gears 7 is non-rotatably fitted to the upper end of the upper part 40b of the optical element holder, instead of the knob 41 in the embodiment described above, and is rotatable integrally with the optical element holder. Each of the multiple small gears 7 meshes with the large gear 6 and rotates with the rotation of the large gear 6. In the embodiment described above, each of the multiple optical element holders 4 is rotated by manually turning the knob 41, but in this modified example, all of the multiple optical element holders 4 can be rotated at once by rotating the large gear 6 by the power of a motor or the like. [Explanation of symbols]

[0047] 100 Optical measurement device, 1 Light source, 2 Sample cell, 3 Detection unit, 4 Optical element holder, 5 Optical element holder support unit, 6 Large gear, 7 Small gear, 40 Main body, 41 Knob, 401 Optical element, 402 Opening, 51 Spacer, L Light, SL Scattered light, LP Path, AR Rotation axis, TH Through hole, CR Rotation center.

Claims

1. A light source; a sample cell that contains a sample and into which light from the light source is incident; A detection unit that detects light emitted from the sample cell; an optical element holder having a rotation axis perpendicular to a plane determined by a path of the emitted light from the sample cell toward the detection unit, and holding a plurality of optical elements including a first optical element and a second optical element each provided around the rotation axis so as to face the rotation axis; an optical element holder support portion that supports the optical element holder so as to be rotatable around the rotation axis; Equipped with the optical element holder is rotatable at least between a first position in which the first optical element is positioned on the path and a second position in which the second optical element is positioned on the path. Light scattering measurement device.

2. the optical element holder has a main body and holds the plurality of optical elements on a side surface of the main body; A side surface of the main body is provided with a plurality of openings including a first opening opened on a side opposite the first optical element and a second opening opened on a side opposite the second optical element.

2. The light scattering measurement device according to claim 1.

3. the rotation axis is located on the path, and is sandwiched between the first optical element and the first opening, and is sandwiched between the second optical element and the second opening.

3. The light scattering measurement device according to claim 2.

4. the plurality of optical elements and the plurality of openings are disposed at equal angular intervals all around the rotation axis, 4. The light scattering measurement device according to claim 3.

5. The optical element holder includes a polygonal portion in cross section.

5. The light scattering measurement device according to claim 4.

6. The plurality of openings includes a third opening and a fourth opening facing each other.

3. The light scattering measurement device according to claim 2.

7. The first optical element and the second optical element are each a polarizing element.

2. The light scattering measurement device according to claim 1.

8. The direction of the polarization axis of the first optical element and the direction of the polarization axis of the second optical element are different from each other.

8. The light scattering measurement device according to claim 7.

9. A plurality of the detection units including a first detection unit and a second detection unit adjacent to the first detection unit; a plurality of the optical element holders including a first optical element holder corresponding to the first detection unit and a second optical element holder corresponding to the second detection unit; 2. The light scattering measurement device according to claim 1.

10. A first gear; a second gear that meshes with the first gear, rotates with the rotation of the first gear, and is rotatable integrally with the first optical element holder; a third gear that meshes with the first gear, rotates with the rotation of the first gear, and is rotatable integrally with the second optical element holder; 10. The light scattering measurement device according to claim 9.

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