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 an optical scattering measurement device. 【Background Art】 【0002】 In an optical scattering measurement device, an optical element holder holding an optical element that changes optical characteristics such as a polarization direction may be provided between a sample cell and a detection unit. For example, when measuring the anisotropy of a measurement sample using an optical scattering measurement device, a polarization 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 these optical elements with each other. For example, when it is desired to extract and measure a longitudinal linearly polarized component and a transverse linearly polarized component from scattered light from a measurement sample, it is necessary to switch between a polarization element with a longitudinal polarization axis and a polarization element with a transverse polarization axis. 【0004】 Conventionally, various optical element holders that enable switching between a plurality of optical elements have been studied. For example, in the field related to variable polarization wafer inspection, a technique of switching the polarization direction by sliding a plate-shaped holder on which a plurality of polarization elements are arranged in the horizontal direction (see FIG. 3 of Patent Document 1 below) is known. Also, in the field related to the external appearance measurement of a birefringent fiber, a technique of switching the polarization direction by arranging a plurality of polarization elements on a disk-shaped holder having a rotation axis parallel to the optical path and rotating this holder around the rotation axis (see FIG. 3A of Patent Document 2 below) is known. 【Prior Art Documents】 【Patent Documents】 【0005】 【Patent Document 1】 Tokuhyo 2015-516574 【Patent Document 2】 JP 2011-069805 A 【Summary of the Invention】 [Problems that the invention aims to solve] 【0006】 On the other hand, conventional optical element holders, such as those described in the above-mentioned patent document, require a large space for installation. This is because, in conventional optical element holders, multiple optical elements are arranged on the same plane. Specifically, in conventional optical element holders, multiple optical elements are arranged on a plate-shaped or disc-shaped substrate. All of these optical elements face the same direction, that is, the same direction as the path of light incident towards the optical element holder. In this case, only one of the multiple optical elements is involved in measurement, i.e., placed on the path of light. Of the multiple optical elements, the optical elements other than this one do not participate in measurement, yet they occupy a certain amount of space in the width direction of the substrate in the optical element holder. As a result, dead space is created by this certain amount of space. 【0007】 Therefore, using the conventional optical element holder described above leads to the problem of the light scattering measurement device itself becoming larger. In particular, when the light scattering measurement device has two or more detection units, that is, when performing measurements using the multi-angle light scattering method, two or more optical element holders are also required. In this case, if the conventional optical element holder is used, the dead space increases, making the increase in the size of the measurement device even more pronounced. 【0008】 The present invention has been made in view of the above problems, and its purpose is to provide a light scattering measuring device equipped with an optical element holder that contributes to the miniaturization of the light scattering measuring device. [Means for solving the problem] 【0009】 (1) The light scattering measuring device according to the present invention comprises a light source, a sample cell containing a sample and into which light from the light source is incident, a detection unit for detecting emitted light emitted from the sample cell, an optical element holder having a rotation axis perpendicular to a plane determined by the 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 so as to face the rotation axis around 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 between at least a first orientation in which the first optical element is located on the path and a second orientation in which the second optical element is located on the path. 【0010】 (2) In the light scattering measuring apparatus of (1), the optical element holder has a main body and holds the plurality of optical elements on the side surface of the main body, and the side surface of the main body may be provided with a plurality of 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 rotating shaft may be located on the path and sandwiched between the first optical element and the first aperture, and also sandwiched between the second optical element and the second aperture. 【0012】 (4) In the light scattering measuring device of (3), the plurality of optical elements and the plurality of apertures may be arranged at equal angular intervals around the entire circumference of the rotation axis. 【0013】 (5) In any of the light scattering measuring devices described in (1) to (4), the optical element holder may include a polygonal portion in its cross-section. 【0014】 (6) In any of the light scattering measuring devices described in (2) to (5), the plurality of apertures may include a third aperture and a fourth aperture that face each other. 【0015】 (7) In any of the light scattering measuring devices described in (1) to (6), the first optical element and the second optical element may each be polarizing elements. 【0016】 (8) In any of the light scattering measuring devices described in (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 described in (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 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 described in (1) to (9) may include a first gear, a second gear that meshes with the first gear and rotates in conjunction 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 and rotates in conjunction with the rotation of the first gear and is rotatable integrally with the second optical element holder. [Brief explanation of the drawing] 【0019】 [Figure 1] This is a perspective view showing a light scattering measurement device according to an embodiment of the present invention. [Figure 2] This figure schematically shows the planar arrangement of a light scattering measuring device according to an embodiment of the present invention. [Figure 3] This is a perspective view showing an optical element holder according to an embodiment of the present invention. [Figure 4] This is a side view showing an optical element holder according to an embodiment of the present invention. [Figure 5] This is a longitudinal cross-sectional view of Figure 4, cut by a plane containing the axis of rotation AR. [Figure 6] This is a cross-sectional view of Figure 4 taken from the VI-VI line. [Figure 7]It is a perspective view showing an optical scattering measurement device according to a modified example. 【Embodiments for Carrying Out the Invention】 【0020】 Hereinafter, embodiments of the present invention will be described in detail based on the drawings. 【0021】 First, using FIGS. 1 and 2, an overview of the optical scattering measurement device according to an embodiment of the present invention will be described. FIG. 1 is a perspective view showing the optical scattering measurement device according to an embodiment of the present invention. FIG. 2 is a diagram schematically showing the planar arrangement of the optical scattering measurement device according to an embodiment of the present invention. 【0022】 As shown in FIGS. 1 and 2, the optical scattering detection device 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 5. The optical scattering detection device 100 of the present embodiment is a multi-angle light scattering measurement device. 【0023】 The light source 1 generates light L that irradiates the sample. The sample cell 2 is a transparent container that houses the sample. Light L from the light source 1 is incident on the sample cell 2 (the sample inside the sample cell 2). Scattered light SL is emitted from the sample cell 2 (the sample inside the sample cell 2) in a plurality of directions that are different from each other by an angle θ around the sample cell 2. 【0024】 Each of the plurality of detection units 3 detects the scattered light SL corresponding to the detection unit 3 among the scattered lights SL emitted in the plurality of directions. Therefore, each of the plurality of detection units 3 is provided on the circumference C1 surrounding the sample cell 2 so as to be adjacent to each other with an angle θ apart from each other around the sample cell 2 (FIG. 2). The output of each of the plurality of 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 angular dependence of the intensity of the scattered light SL detected by each of the plurality of detection units 3. In the present embodiment, it is assumed that the sample is a liquid sample, but the sample may be a solid sample. 【0025】 Each of the multiple optical element holders 4 holds a first optical element 401-1 and a second optical element 401-2, as will be described later (see Figures 3-6). Each of the multiple optical element holders 4 is provided between the sample cell 2 and the detection unit 3 corresponding to the optical element holder 4. element Each of the holders 4 is positioned adjacent to the others at an angle θ on a concentric circumference C2 that surrounds the sample cell 2 and is located inside the circumference C1 (Figure 2). Each of the multiple optical element holders 4 is rotatable between a first orientation in which the first optical element 401-1 is positioned on the path LP of scattered light SL from the sample cell 2 toward the detection unit 3 corresponding to the optical element holder 4, and a second orientation in which the second optical element 401-2 is positioned on the path LP (see Figures 3-6). 【0026】 In this way, since each of the multiple optical element holders 4 is rotatable between the first and second orientations, the light scattering measuring device 100 can switch between measurements using the first optical element 401-1 and measurements using the second optical element 401-2. Although Figures 1 and 2 show cases where the number of detection units 3 and optical element holders 4 is 11 each, the number of detection units 3 and optical element holders 4 may be fewer or more than this. 【0027】 As described above, the optical element holder support section 5 supports multiple optical element holders 4 so that they can rotate. Specifically, the optical element holder support section 5 is formed from an annular plate material along the circumference C2, and the sample cell 2 is placed in the hole at the center of the annular shape. Note that the shape of the optical element holder support section 5 is not limited to an annular shape and may be other shapes. 【0028】 The optical element holder 4 will be described in detail below. First, the overall structure of the optical element holder 4 will be described using Figures 3 to 5. Figure 3 is a perspective view showing an optical element holder according to an embodiment of the present invention. Figure 4 is a side view showing an optical element holder according to an embodiment of the present invention. Figure 5 is a longitudinal cross-sectional view of Figure 4, cut along a plane including the rotation axis AR. Note that Figures 3 to 5 only show the path LP and a portion of the optical element holder support portion 5. 【0029】 As shown in Figures 3 to 5, the optical element holder 4 has a main body 40 and a knob 41. The main body 40 includes a lower part 40a and an upper part 40b. 【0030】 The lower part 40a is hexagonal prism-shaped, and the upper part 40b is cylindrical (Figure 3). The central axis of the lower part 40a and the central axis of the upper part 40b are aligned on the same straight line (Figure 5), and this straight line becomes the rotation axis AR of the optical element holder 4. Note that the shape of the lower part 40a is not limited to a hexagonal prism; it may also be cylindrical, hemispherical, or other shapes. 【0031】 The lower end of the upper part 40b is rotatably supported by the optical element holder support part 5 via spacers 51, 51 (Figure 5). The shape of the spacers 51, 51 is that of an annular plate with a cylindrical wall rising from its inner circumference. Multiple holes are made on the optical element holder support part 5 along the circumference C2, and one of the spacers 51, 51 is fitted into each hole from the upper side, and the other of the spacers 51, 51 is fitted into each hole from the lower side. b A cylindrical knob 41 is fitted non-rotatably to the upper end (Figures 3 and 5). This allows the user to rotate the optical element holder 4 around the rotation axis AR by grasping the knob 41. The shape of the knob 41 may be other than cylindrical. 【0032】 The details of the optical element holder 4 will be described below with further reference to Figure 6. Figure 6 is a cross-sectional view of Figure 4 taken along the line VI-VI. 【0033】 The lower part 40a is provided with a first through-hole TH1 and a second through-hole TH2 that penetrate opposing sides (Figure 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. Furthermore, 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, scattered light SL incident on the first optical element 401-1 passes through the first through-hole TH1 and exits from the first aperture 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, scattered light SL incident on the second optical element 401-2 passes through the second through-hole TH2 and exits from the second aperture 402-2, so that the detection unit 3 can detect the scattered light SL that has passed through the second optical element 401-2. Alternatively, scattered light SL incident on the first aperture 402-1 may pass through the first through-hole TH1 and then through the first optical element 401-1. Also, scattered light SL incident on the second aperture 402-2 may pass through the second through-hole TH2 and then through the second optical element 401-2. 【0035】 Furthermore, a third through-hole TH3 is provided in the lower part 40a, penetrating the opposing side surface (Figure 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. Also, 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 through-holes in which no optical elements are installed, even when the light scattering measuring device 100 is equipped with an optical element holder 4, normal measurements can be performed without involving the first optical element 401-1 and the second optical element 401-2. 【0036】 Furthermore, 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. Also, the optical element holder 4 may have five or more openings. Moreover, the arrangement of the first optical element 401-1 and the second optical element 401-2 is not limited to that shown in Figure 6; for example, the first optical element 401-1 and the second optical element 401-2 may be in adjacent positions. 【0037】 Furthermore, although the openings such as the first opening 402-1 were circular holes (Figure 3, etc.), they may be changed to shapes other than holes, as long as they still perform the function of allowing light to pass through. For example, the opening may be a notch provided at the upper or lower end of the lower part 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 (Figure 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 (Figure 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 (Figure 6). Also, the rotation axis AR is located on the path LP and is perpendicular to the path LP (Figures 3-5). 【0039】 As a result, when the optical element holder 4 is rotated, scattered light SL can pass through the first through-hole TH1, the second through-hole TH2, and the third through-hole TH3. Insofar as this effect is achieved, the rotation axis AR and the path LP may intersect in a manner other than orthogonal. Also, insofar as this effect is achieved, 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 orthogonal. Furthermore, the rotation axis AR does not have to be located on the path LP, and may intersect the path LP in a manner other than orthogonal as long as the above effect is achieved. 【0040】 The first optical element 401-1 and the second optical element 401-2 are each plate-shaped with two main surfaces. Here, the normal directions 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) are perpendicular to the rotation axis AR (Figures 5-6). In other words, the first optical element 401-1 and the second optical element 401-2 are each arranged so as to face the rotation axis AR around the rotation axis AR. That is, since the multiple optical elements 401 are not arranged on the same plane, the dead space caused by optical elements not involved in measurement can be reduced, and the optical element holder 4 can be made smaller. The main surfaces of the first optical element 401-1 and the second optical element 401-2 may be flat or curved. 【0041】 The first optical element 401-1 and the second optical element 401-2 are, in this example, polarizing elements (polarizing plates). The polarization axis direction of the first optical element 401-1 is parallel to the rotation axis AR, i.e., the vertical direction, and the polarization axis direction of the second optical element 401-2 is perpendicular to the rotation axis AR, i.e., the horizontal direction. 01-1 The direction of the polarization axis and the second optical element 4 01-2 The direction of the polarization axis can be arbitrarily set according to the purpose of the measurement. In addition, various optical elements can be selected as the first optical element 401-1 and the second optical element 401-2, such as an ND filter for adjusting the amount of light or a colored glass filter for adjusting the wavelength, in addition to a polarizing element. For example, one of the first optical element 401-1 and the second optical element 401-2 may be a polarizing element, and the other of the first optical element 401-1 and the second optical element 401-2 may be an ND filter, or different types of optical elements may be used in an appropriate combination. 【0042】 Incidentally, 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 aperture 402-1 are arranged to sandwich the rotation axis AR, while the second optical element 401-2 and the second aperture 402-2 are also arranged to sandwich the rotation axis AR (Figures 5-6). With this configuration, the side surface of the lower part 40a of the optical element holder 4 can be utilized more effectively, and thus the optical element holder 4 can be made smaller. 【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 third through hole TH 3 The direction of the center line CL3 and the direction of the aperture differ by 60 degrees around the rotation center CR (Figure 6). That is, the first optical element 401-1, the third aperture 402-3, the second optical element 401-2, the first aperture 402-1, the fourth aperture 402-4, and the second aperture 402-2 are arranged at equal angular intervals around the entire circumference of the rotation axis AR. With this configuration, the side surface of the lower part 40a of the optical element holder 4 can be used to the maximum extent, so the optical element holder 4 can be made even smaller. 【0044】 It should be noted that the present invention is not limited to the above embodiments, and various modifications are possible. Hereinafter, one modified example of the present invention will be described with reference to Figure 7. Figure 7 is a perspective view showing a light scattering measuring device according to the modified example. 【0045】 In this modified example, the light scattering measuring device 100 further comprises a large gear 6 and a plurality of small gears 7. The large gear 6 is mounted on the optical element holder support portion 5, and its multiple teeth surround the sample cell 2. The rotation axis of the large gear 6 is parallel to the rotation axis AR of each of the plurality of optical element holders 4. 【0046】 Each of the multiple small gears 7 is non-rotatably fitted into the upper end of the upper part 40b of the optical element holder, instead of the knob 41 in the previously described embodiment, and is rotatable integrally with the optical element holder. Each of the multiple small gears 7 meshes with the large gear 6 and rotates in conjunction with the rotation of the large gear 6. In the previously described embodiment, each of the multiple optical element holders 4 was rotated by manually turning the knob 41, but in this modified example, all of the multiple optical element holders 4 can be rotated simultaneously by rotating the large gear 6 with a power source such as a motor. [Explanation of symbols] 【0047】 100 Optical measuring device, 1 Light source, 2 Sample cell, 3 Detection unit, 4 Optical element holder, 5 Optical element holder support, 6 Large gear, 7 Small gear, 40 Main body, 41 Knob, 401 Optical element, 402 Aperture, 51 Spacer, L Light, SL Scattered light, LP Path, AR Rotation axis, TH Through hole, CR Rotation center.

Claims

[Claim 1] Light source and A sample cell containing the sample and into which light from the light source is incident, A detection unit for detecting emitted light from the sample cell, An optical element holder having a rotation axis perpendicular to a plane determined by the path of the emitted light from the sample cell toward the detection unit, and holding a plurality of polarizing elements including a first polarizing element and a second polarizing element, each provided so as to face the rotation axis around the rotation axis, An optical element holder support portion that supports the optical element holder so that it can rotate around the rotation axis, Equipped with, The optical element holder is rotatable at least between a first orientation in which the first polarizing element is located on the path and a second orientation in which the second polarizing element is located on the path. Light scattering measurement device. [Claim 2] The optical element holder has a main body and holds the plurality of polarizing elements on the side surface of the main body. The side surface of the main body is provided with a plurality of openings, including a first opening opened on the opposite side of the first polarizing element and a second opening opened on the opposite side of the second polarizing element. The light scattering measuring device according to claim 1. [Claim 3] The rotation axis is located on the path and is sandwiched between the first polarizing element and the first aperture, and also sandwiched between the second polarizing element and the second aperture. The light scattering measuring device according to claim 2. [Claim 4] The plurality of polarizing elements and the plurality of apertures are arranged at equal angular intervals around the entire circumference of the rotation axis. The light scattering measuring device according to claim 3. [Claim 5] The optical element holder includes a polygonal portion in its cross-section. The light scattering measuring device according to claim 4. [Claim 6] The plurality of openings include a third opening and a fourth opening that face each other. The light scattering measuring device according to claim 2. [Claim 7] The direction of the polarization axis of the first polarizing element and the direction of the polarization axis of the second polarizing element are different from each other. The light scattering measuring device according to claim 1. [Claim 8] A plurality of detection units, including a first detection unit and a second detection unit adjacent to the first detection unit, The optical element holder comprises a plurality of 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. The light scattering measuring device according to claim 1. [Claim 9] The first gear and A second gear meshes with the first gear, rotates in conjunction with the rotation of the first gear, and is rotatable integrally with the first optical element holder, The system comprises a third gear that meshes with the first gear, rotates in conjunction with the rotation of the first gear, and is rotatable integrally with the second optical element holder. The light scattering measuring device according to claim 8.

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