Fourier transform infrared spectrophotometer

Abstract

Provided is a Fourier transform infrared spectrophotometer having a configuration that is less likely to conduct heat from an infrared light source to an interferometer. A Fourier transform infrared spectrophotometer (100) comprises: an infrared light source (21) that emits infrared light; an interferometer (10) that includes a beam splitter, a fixed mirror, and a moving mirror, and that generates interference light from the infrared light; and a base plate (2) that has a first section (2a) where the infrared light source (21) is disposed and a second section (2b) where the interferometer (10) is disposed. The base plate (2) has a shape in which the first section (2a) and the second section (2b) form a predetermined angle.

Description

[Technical Field]

[0001] The present disclosure relates to Fourier transform infrared spectrophotometers. [Background technology]

[0002] Conventionally, in a Fourier transform infrared spectrophotometer (FT-IR), an infrared light source and an interferometer are arranged on a two-dimensional flat base plate, as shown in Registered Utility Model No. 3113903 (Patent Document 1). In a Fourier transform infrared spectrophotometer, infrared light irradiated from the infrared light source arranged on the base plate is introduced into the interferometer, and a sample placed in a sample chamber is analyzed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Registered Utility Model No. 3113903 Summary of the Invention [Problem to be solved by the invention]

[0004] However, since infrared light sources emit heat while emitting infrared light, if this heat is transmitted to the interferometer, optical elements such as the beam splitter that constitutes the interferometer and their holders will thermally expand, causing a change in the optical axis and potentially degrading measurement accuracy. Therefore, in Fourier transform infrared spectrophotometers, it has been necessary to take thermal countermeasures, such as providing a heater cover to prevent the heat from the infrared light source from being transmitted to the interferometer, or using a highly thermally conductive material for the base on which the infrared light source and interferometer are placed so that heat is transmitted in a direction away from the interferometer.

[0005] An object of the present disclosure is to provide a Fourier transform infrared spectrophotometer configured to transmit less heat from an infrared light source to an interferometer. [Means for solving the problem]

[0006] The Fourier transform infrared spectrophotometer of the present disclosure includes an infrared light source that emits infrared light, an interferometer that includes a beam splitter, a fixed mirror, and a movable mirror and generates interference light from the infrared light, and a base plate having a first portion in which the infrared light source is disposed and a second portion in which the interferometer is disposed, and the base plate includes: the surface on which the infrared light source is disposed and the second part the surface on which the interferometer is disposed The infrared light source and the interferometer are arranged on opposite sides of the base plate, and a first space in which the infrared light source is arranged in the first part and a second space in which the interferometer is arranged in the second part are spaces separated by the base plate, and the base plate has a window for introducing light from the infrared light source from the first space to the second space. [Effects of the Invention]

[0007] According to the Fourier transform infrared spectrophotometer of the present disclosure, it is possible to obtain a configuration that makes it more difficult for heat from the infrared light source to be transmitted to the interferometer. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a Fourier transform infrared spectrophotometer according to an embodiment. [Figure 2] FIG. 1 is a block diagram of a Fourier transform infrared spectrophotometer according to an embodiment. [Figure 3] FIG. 1 is a perspective view illustrating the inside of a Fourier transform infrared spectrophotometer according to an embodiment. [Figure 4] FIG. 2 is a perspective view from another angle illustrating the inside of the Fourier transform infrared spectrophotometer according to the embodiment. [Figure 5] FIG. 2 is a perspective view for explaining a light source unit of the Fourier transform infrared spectrophotometer according to the embodiment. [Figure 6] FIG. 2 is a cross-sectional view illustrating a light source unit of the Fourier transform infrared spectrophotometer according to the embodiment. [Figure 7] FIG. 2 is a bottom view illustrating heat exhaust from the Fourier transform infrared spectrophotometer according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described. Note that the same reference numerals are used to designate the same components, and the description thereof will not be repeated.

[0010] A Fourier transform infrared spectrophotometer 100 according to an embodiment will be described with reference to Figures 1 and 2. Figure 1 is a schematic diagram of the Fourier transform infrared spectrophotometer 100 according to an embodiment. Figure 2 is a block diagram of the Fourier transform infrared spectrophotometer 100 according to an embodiment. The Fourier transform infrared spectrophotometer 100 includes an interferometer 10, a light source unit 20, a circuit unit 30, a sample chamber 40, and a detection unit 50. Figure 1 shows a plan view of the Fourier transform infrared spectrophotometer 100 as seen from above, illustrating the arrangement of the interferometer 10, the light source unit 20, the circuit unit 30, the sample chamber 40, and the detection unit 50 in a housing 1.

[0011] The upper side of Fig. 1 is the front side of the Fourier transform infrared spectrophotometer 100, and the lower side of Fig. 1 is the rear side of the Fourier transform infrared spectrophotometer 100. The interferometer 10, light source unit 20, and circuit unit 30 are arranged on the rear side of the Fourier transform infrared spectrophotometer 100, with the interferometer 10, light source unit 20, and circuit unit 30 arranged side by side in this order from the left side of Fig. 1. The interferometer 10 is attached to one part of an L-shaped base plate 2, which will be described later, and the light source unit 20 is attached to another part of the base plate 2.

[0012] The sample chamber 40 and the detection unit 50 are arranged on the front side of the Fourier transform infrared spectrophotometer 100, with the sample chamber 40 and the detection unit 50 arranged side by side from the left side in Fig. 1. The sample chamber 40 is covered with a lid member, and the sample to be measured is placed in the sample chamber 40 by opening the lid member.

[0013] The specific configuration of Fourier transform infrared spectrophotometer 100 will be described using Figure 2. First, interferometer 10 includes beam splitter 11, fixed mirror 12, movable mirror 13, etc., and light source unit 20 includes infrared light source 21, focusing mirror 22, collimator mirror 23, etc. Interferometer 10 and light source unit 20 generate coherent infrared light for spectrum measurement. That is, infrared light emitted from infrared light source 21 is irradiated onto beam splitter 11 via focusing mirror 22 and collimator mirror 23, where it is split into two directions, toward fixed mirror 12 and movable mirror 13.

[0014] The light reflected by fixed mirror 12 and movable mirror 13 is combined again by beam splitter 11 and sent to the optical path toward parabolic mirror 42. At this time, movable mirror 13 moves back and forth (in the direction of the arrow in Figure 2), so the combined light becomes interference light (interferogram) whose amplitude varies over time. The light collected by parabolic mirror 42 is irradiated into sample chamber 40, and the light that passes through sample 41 placed in sample chamber 40 enters detection unit 50. The light that enters detection unit 50 is collected onto photodetector 52 by ellipsoidal mirror 51.

[0015] The Fourier transform infrared spectrophotometer 100 includes a main interferometer for obtaining an interferogram and a control interferometer for controlling the sliding speed of the movable mirror 13 and generating timing signals for sampling the signal obtained by the detector of the main interferometer. The control interferometer is composed of a laser light source 24, a mirror 14, a beam splitter 11, a fixed mirror 12, a movable mirror 13, etc., and generates laser interference light for obtaining an interference fringe signal. That is, the light emitted from the laser light source 24 is irradiated onto the beam splitter 11 via the mirror 14, and like the infrared light, it becomes interference light and is sent toward the parabolic mirror 42. Because this laser interference light travels as a beam of light with an extremely small diameter, it is reflected by a mirror 15 inserted in the optical path and introduced into the photodetector 16.

[0016] The optical components, including the interferometer 10, are placed in a humidity-controlled airtight chamber, primarily to protect the optical components, such as the beam splitter 11, which uses deliquescent KBr as its substrate.

[0017] The light-receiving signal from the photodetector 16, i.e., the laser light interference fringe signal, is input to the signal generator 32, which generates a pulse signal for sampling the light-receiving signal for the infrared interference light. The light-receiving signal obtained by the photodetector 52 is amplified by the amplifier 33, sampled by the sample-and-hold circuit (S / H) 34 at the timing determined by the pulse signal, and then converted into digital data by the A / D converter (A / D) 35. The data processor 36 performs a Fourier transform on this data to create an absorption spectrum, and further creates a transmittance spectrum using background data. The series of measurement operations is performed under the control of the controller 31. The controller 31, signal generator 32, amplifier 33, sample-and-hold circuit (S / H) 34, A / D converter (A / D) 35, and data processor 36 are included in the circuit unit 30.

[0018] Since infrared light source 21 emits heat while emitting infrared light, this heat may be transferred to interferometer 10, changing the optical axis entering beam splitter 11 and other optical elements that make up interferometer 10 and potentially degrading measurement accuracy. For this reason, in Fourier transform infrared spectrophotometer 100, the interferometer 10 and infrared light source 21 are arranged in a way that makes it difficult for heat from infrared light source 21 to be transferred to interferometer 10. The arrangement of interferometer 10 and infrared light source 21 will be described below with reference to the drawings.

[0019] Fig. 3 is a perspective view illustrating the interior of a Fourier transform infrared spectrophotometer 100 according to an embodiment. Fig. 4 is a perspective view from a different angle illustrating the interior of a Fourier transform infrared spectrophotometer according to an embodiment. As described above, the interferometer 10 and the light source unit 20 are required to generate coherent infrared light, and therefore require high positional accuracy. For this reason, in conventional Fourier transform infrared spectrophotometers, the infrared light source and the interferometer are arranged on a two-dimensional flat base plate.

[0020] However, in the Fourier transform infrared spectrophotometer 100 according to this embodiment, instead of a two-dimensional flat base plate, the infrared light source 21 and the interferometer 10 are arranged on an L-shaped base plate 2. The L-shaped base plate 2 has a first portion 2a that is provided horizontally with respect to the installation surface of the Fourier transform infrared spectrophotometer 100, and a second portion 2b that is provided perpendicular to the installation surface.

[0021] The first section 2a is disposed horizontally relative to the installation surface of the Fourier transform infrared spectrophotometer 100, with the surface facing the installation surface being the lower surface and the surface opposite the installation surface being the upper surface. The infrared light source 21 is disposed on the upper surface of the first section 2a. Specifically, as shown in FIG. 3, the infrared light source 21 is disposed on the upper surface of the first section 2a via a holding block 25. In addition to the infrared light source 21, a light source unit 20 including a collecting mirror 22, a collimator mirror 23, and a laser light source 24 is disposed in the space above the first section 2a.

[0022] On the other hand, second portion 2b is provided perpendicular to the installation surface of Fourier transform infrared spectrophotometer 100, with the surface in contact with first portion 2a being the inner surface and the surface opposite to the inner surface being the outer surface. Interferometer 10 is disposed on the outer surface of second portion 2b.

[0023] Therefore, infrared light emitted from infrared light source 21 is reflected by collecting mirror 22, which is provided below infrared light source 21, and is introduced into interferometer 10 by collimator mirror 23, which is arranged above collecting mirror 22. Second portion 2b is provided with window 4 so that light from collimator mirror 23 can be introduced into interferometer 10. Collecting mirror 22 and collimator mirror 23 are fixed to the inner surface of second portion 2b, as shown in FIG. 3.

[0024] The infrared light source 21, which is located on the top surface of the first section 2a, is located on the inner surface of the second section 2b. Therefore, the interferometer 10, which is located on the outer surface of the second section 2b, is located on the opposite side of the second section 2b from the infrared light source 21. Therefore, the necessary light is introduced into the interferometer 10 through the window 4, and heat emitted from the infrared light source 21 is not directly transmitted to the interferometer 10. In particular, as shown in FIG. 4, the interferometer 10 is covered with a cover member 5 made of, for example, a resin material to ensure airtightness, which makes it difficult to provide a heat dissipation structure. Using a resin material for the cover member 5 allows the Fourier transform infrared spectrophotometer 100 to be lightweight. The cover member 5 is not limited to a resin material and may be made of a metal material.

[0025] The L-shape of the base plate 2 allows the second portion 2b to block the heat emitted from the infrared light source 21. In other words, the second portion 2b can separate the section of the interferometer 10, which is difficult to implement a heat dissipation structure, from the section of the light source unit 20, which is easy to implement a heat dissipation structure.

[0026] In this way, by devising the shape of base plate 2, it is possible to ensure high positional accuracy while enabling a three-dimensional arrangement in which the heat emitted from infrared light source 21 is not directly transmitted to interferometer 10. Furthermore, compared to when infrared light source 21 and interferometer 10 are arranged on a two-dimensional plane, the degree of freedom in the arrangement of infrared light source 21 and interferometer 10 is increased, which can also contribute to making Fourier transform infrared spectrophotometer 100 more compact.

[0027] The base plate 2 has been described as having an L-shape in which the first portion 2a and the second portion 2b form an angle of approximately 90°. However, the shape of the base plate 2 is not limited to an L-shape, and may be any shape in which the first portion 2a and the second portion 2b form a predetermined angle. Note that the predetermined angle may be any angle other than an angle at which the first portion 2a and the second portion 2b are horizontal (for example, 180°).

[0028] The base plate 2 preferably has a structure in which the first portion 2a and the second portion 2b are integrally formed. By making the base plate 2 an integrally formed structure, the positional accuracy between the infrared light source 21 and the interferometer 10 arranged on the base plate 2 is increased. Of course, the first portion 2a and the second portion 2b may be formed as separate bodies as long as the positional accuracy between the infrared light source 21 and the interferometer 10 required for measurement can be ensured. Furthermore, by using a material with a higher thermal conductivity for the first portion 2a where the infrared light source 21 is arranged than for the second portion 2b, heat from the infrared light source 21 can be more easily dissipated from the first portion 2a.

[0029] The heat emitted from the infrared light source 21 will be described in more detail. FIG. 5 is a perspective view illustrating the light source unit of the Fourier transform infrared spectrophotometer 100 according to the embodiment. FIG. 6 is a cross-sectional view illustrating the light source unit of the Fourier transform infrared spectrophotometer 100 according to the embodiment. First, the infrared light source 21 is fixed to the upper surface of the first section 2a by a holding block 25 as shown in FIG. 5. Specifically, the infrared light source 21 is disposed in the first section 2a at an angle such that the optical axis from the infrared light source 21 is oblique to the upper surface of the first section 2a in order to irradiate the collecting mirror 22 with infrared light.

[0030] 6, the infrared light source 21 has a light-emitting unit 21a that emits infrared light and a cover 21b that covers the light-emitting unit 21a. The cover 21b has a slit 21c that allows the infrared light to be irradiated onto the collecting mirror 22. Light other than the infrared light irradiated from the slit 21c is confined inside the infrared light source 21 by the cover 21b. As a result, heat is generated within the infrared light source 21, and the temperature of the infrared light source 21 itself, particularly the temperature of the cover 21b, rises.

[0031] A heat insulating member 25a is provided on the portion of the holding block 25 that comes into contact with the infrared light source 21 so that the heat generated by the infrared light source 21 does not escape to the holding block 25. In other words, the infrared light source 21 is placed on the upper surface of the first portion 2a via the heat insulating member 25a. This prevents the heat generated by the infrared light source 21 from being transmitted to the base plate 2 via the holding block 25.

[0032] Even if the holding block 25 is provided with the heat insulating member 25a, some of the heat generated by the infrared light source 21 is still conducted to the base plate 2. Therefore, the heat conducted to the first portion 2a of the base plate 2 is actively dissipated on the first portion 2a side so as not to be conducted to the second portion 2b side where the interferometer 10 is arranged. Specifically, the upper surface of the first portion 2a is divided into a first region on the second portion 2b side and a second region on the opposite side of the second portion 2b, with the position where the infrared light source 21 is arranged as the boundary, and the area of ​​the second region is made larger than the area of ​​the first region. As a result, a large area is secured in the first portion 2a on the opposite side of the second portion 2b where the interferometer 10 is arranged, and heat can be actively dissipated in that region.

[0033] An air window 3 is provided in the housing 1 below the first portion 2a so that heat from the infrared light source 21 transferred to the first portion 2a can be dissipated from the underside of the first portion 2a to the outside of the housing 1. Figure 7 is a bottom view illustrating heat dissipation from the Fourier transform infrared spectrophotometer 100 according to the embodiment. As shown in Figure 7, multiple air windows 3 are provided on the bottom surface of the housing 1, allowing the heat from the infrared light source 21 to be efficiently dissipated from the underside of the first portion 2a.

[0034] [Aspect] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0035] (Item 1) A Fourier transform infrared spectrophotometer according to one embodiment includes an infrared light source that emits infrared light, an interferometer that includes a beam splitter, a fixed mirror, and a movable mirror and generates interference light from the infrared light, and a base plate having a first portion in which the infrared light source is disposed and a second portion in which the interferometer is disposed, and the base plate is shaped so that the first portion and the second portion form a predetermined angle.

[0036] Therefore, the Fourier transform infrared spectrophotometer disclosed herein can achieve a configuration that makes it more difficult for heat from the infrared light source to be transmitted to the interferometer. Furthermore, because the base plate has a shape in which the first and second portions form a predetermined angle, the infrared light source and the interferometer can be arranged three-dimensionally, which increases the degree of freedom in the arrangement of the infrared light source and the interferometer, and can also contribute to making the Fourier transform infrared spectrophotometer more compact.

[0037] (Item 2) In the Fourier transform infrared spectrophotometer described in item 1, the base plate has an L-shape formed by the first portion and the second portion.

[0038] Therefore, the interferometer placed in the second part can be placed vertically, and the heat from the infrared light source can be blocked by the second part of the base plate, while the Fourier transform infrared spectrophotometer can be made compact.

[0039] (Item 3) In the Fourier transform infrared spectrophotometer described in item 1 or 2, the base plate has a structure in which the first portion and the second portion are integrally formed.

[0040] Therefore, the positional accuracy of the infrared light source and the interferometer can be increased, and the required coherent infrared light can be generated by the infrared light source and the interferometer.

[0041] (Item 4) In the Fourier transform infrared spectrophotometer according to any one of items 1 to 3, the infrared light source is disposed in the first portion via a heat insulating member.

[0042] Therefore, the heat generated by the infrared light source can be confined within the infrared light source, and the heat leaking to the first portion of the base plate can be reduced.

[0043] (Item 5) In the Fourier transform infrared spectrophotometer described in any one of items 1 to 4, the first part of the base plate is divided into a first region on the second part side and a second region on the opposite side of the second part, with the position where the infrared light source is placed as the boundary, and the area of ​​the second region is larger than the area of ​​the first region.

[0044] Therefore, the heat from the infrared light source that is transferred to the first portion of the base plate can be actively dissipated in the second region having a large area, thereby suppressing temperature changes in the interferometer.

[0045] (Item 6) In the Fourier transform infrared spectrophotometer described in any one of items 1 to 5, the base plate holds the infrared light source at an angle such that the optical axis from the infrared light source is oblique to the top surface of the first part.

[0046] Therefore, the light from the infrared light source can be reflected by the collecting mirror and efficiently introduced into the interferometer by the collimator mirror arranged above the collecting mirror.

[0047] (Item 7) The Fourier transform infrared spectrophotometer according to any one of items 1 to 6 further comprises a cover member that covers the interferometer.

[0048] Therefore, the airtightness of the interferometer can be ensured, and the humidity inside the cover member can be controlled to protect optical components such as a deliquescent beam splitter.

[0049] (Item 8) In the Fourier transform infrared spectrophotometer described in item 7, the cover member is made of a resin material.

[0050] Therefore, by using a resin material for the cover member, it is possible to reduce the weight of the Fourier transform infrared spectrophotometer.

[0051] The embodiments and modifications disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0052] 1 housing, 2 base plate, 2a first part, 2b second part, 3 air window, 4 window, 5 cover member, 10 interferometer, 11 beam splitter, 12 fixed mirror, 13 movable mirror, 14, 15 mirror, 16, 52 photodetector, 20 light source section, 21 infrared light source, 21a light emitting section, 21b cover, 21c slit, 22 focusing mirror, 23 collimator mirror, 24 laser light source, 25 holding block, 25a heat insulating member, 30 circuit section, 31 control section, 32 signal generating section, 33 amplifier, 36 data processing section, 40 sample chamber, 41 sample, 42 parabolic mirror, 50 detection section, 51 ellipsoidal mirror, 100 Fourier transform infrared spectrophotometer.

Claims

1. an infrared light source that emits infrared light; an interferometer including a beam splitter, a fixed mirror, and a movable mirror, for generating interference light from the infrared light; a base plate having a first portion on which the infrared light source is disposed and a second portion on which the interferometer is disposed; the base plate has a bent shape such that a surface of the first portion on which the infrared light source is disposed and a surface of the second portion on which the interferometer is disposed form a predetermined angle, the infrared light source and the interferometer are disposed on opposite sides of the base plate, and a first space in which the infrared light source is disposed in the first portion and a second space in which the interferometer is disposed in the second portion are spaces separated by the base plate; The base plate has a window for introducing light from the infrared light source from the first space to the second space.

2. The base plate according to claim 1 , wherein the first portion and the second portion form an L-shape. Fourier transform infrared spectrophotometer.

3. the base plate has a structure in which the first portion and the second portion are integrally formed.

3. The Fourier transform infrared spectrophotometer according to claim 1 or 2.

4. The housing according to claim 1 , wherein the infrared light source is disposed in the first portion via a heat insulating member. Rie transform infrared spectrophotometer.

5. The first portion of the base plate is a portion of the base plate on the second portion side with respect to the position where the infrared light source is disposed. a first region and a second region opposite the second portion; 2. The film according to claim 1, wherein the area of ​​the second region is larger than the area of ​​the first region. -Rier transform infrared spectrophotometer.

6. The base plate is configured such that the optical axis from the infrared light source is oblique to the upper surface of the first portion.

2. The Fourier transform infrared spectrophotometer of claim 1, wherein the infrared light source is held at an angle.

7. The Fourier transform infrared spectrometer according to claim 1 , further comprising a cover member for covering the interferometer. Photometer.

8. The Fourier transform infrared spectrophotometer according to claim 7 , wherein the cover member is made of a resin material.

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