Infrared light source device and Fourier transform infrared spectrophotometer

Abstract

To miniaturize an infrared light source device while maintaining a light source temperature above a target temperature.SOLUTION: An infrared light source device (1) includes a heater unit (11) that emits infrared light when heated, and a cover member (20) which is arranged so as to cover the entire circumference of the heater unit (11) without contacting the heater unit (11) and has a hole (21a) for emitting infrared light from the heater unit (11) to the outside. The material of the cover member (20) is pure aluminum-based material (aluminum alloy with a purity of 99% or more), which has a high heat reflectance and is not easily denatured by heat radiation from the heater unit (11).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an infrared light source device and a Fourier transform infrared spectrophotometer including the infrared light source device. [Background technology]

[0002] In an FTIR (Fourier Transform Infrared Spectrophotometer), infrared light from an infrared light source device is split into two by a beam splitter, one of which is irradiated onto a fixed mirror and the other onto a movable mirror, and the infrared light reflected by the fixed mirror and the infrared light reflected by the movable mirror are guided back along the same optical path to generate interference light. This interference light is irradiated onto a sample to be measured, and the transmitted or reflected light is detected by a detector, and a detection signal by the detector is sent to a data processing device. The data processing device creates a spectrum by Fourier transforming the detection signal by the detector, and performs qualitative and quantitative analysis of the sample from the peak wavelength, peak intensity, etc. of this spectrum (see, for example, International Publication No. WO 2016 / 166872). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2016 / 166872 Summary of the Invention [Problem to be solved by the invention]

[0004] Infrared light source devices for FTIR generally include a ceramic heater that functions as an infrared light source by being heated to about 1000°C and emitting infrared light, a heat insulating material with low thermal conductivity (such as porous ceramic) that is arranged to cover the periphery of the heater (infrared light source), and a metal cover that covers the periphery of the heat insulating material. By covering the heater in two layers, the heat insulating material and the metal cover, it is possible to maintain the temperature of the heater at or above a target temperature while suppressing the power consumption of the heater.

[0005] In an infrared light source device having the above structure, in order to maintain the temperature of the heater (infrared light source) at or above a target temperature, the thickness of the heat insulating material must be greater than a certain value, which can lead to an increase in the size of the infrared light source device. Therefore, in order to reduce the size of the infrared light source device, an option other than the heat insulating material (porous ceramic, etc.) is required as a member for maintaining the light source temperature at or above a target temperature.

[0006] The present disclosure has been made to solve the above problems, and an object of the present disclosure is to reduce the size of an infrared light source device while maintaining the temperature of the infrared light source at or above a target temperature. [Means for solving the problem]

[0007] The infrared light source device according to the present disclosure includes a heater that emits infrared light when heated, and a cover member that is disposed so as to cover the entire periphery of the heater without contacting the heater and has a hole formed therein for emitting the infrared light from the heater to the outside. The material of the inner wall of the cover member is aluminum or gold.

[0008] A Fourier transform infrared spectrophotometer according to the present disclosure includes the above-described infrared light source device. Effect of the Invention

[0009] According to the present disclosure, it is possible to reduce the size of an infrared light source device while maintaining the temperature of a heater (infrared light source) at or above a target temperature. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of an FTIR spectrometer. [Diagram 2] FIG. 2 is a cross-sectional view of the infrared light source device 1. [Diagram 3] FIG. 2 is a plan view of the ceramic heater. [Figure 4] FIG. [Diagram 5] 5 is a VV cross-sectional view of the cover member in FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0012] FIG. 1 is a diagram illustrating an example of the configuration of an FTIR (Fourier transform infrared spectrophotometer) including an infrared light source device 1 according to the present embodiment.

[0013] This FTIR includes an interferometer chamber 400, a parabolic mirror 432, a sample chamber 470, an ellipsoidal mirror 433, and an infrared photodetector 480. The interferometer chamber 400 contains a main interferometer including an infrared light source device 1, a collecting mirror 431a, a collimator mirror 431b, a beam splitter 440, a movable mirror 450, and a fixed mirror 460. The sample chamber 470 contains a sample S to be measured.

[0014] In the main interferometer in the interferometer chamber 400, the infrared light source device 1 emits infrared light. The infrared light emitted from the infrared light source device 1 passes through a collecting mirror 431a and a collimator mirror 431b, and is split into two by a beam splitter 440. One of the two beams of infrared light split by the beam splitter 440 is reflected by a fixed mirror 460, and the other is reflected by a movable mirror 450, and then the two beams are combined again along the same optical path to become infrared interference light.

[0015] The infrared interference light is emitted from the interferometer chamber 400 towards the parabolic mirror 432, and after being collected by the parabolic mirror 432, is incident on the sample chamber 470. When the infrared interference light is irradiated onto the sample S, it is absorbed at a wavelength specific to the sample S. The absorbed infrared interference light is detected by the infrared photodetector 480 via the ellipsoidal mirror 433 and is Fourier transformed to create a spectrum.

[0016] In such an FTIR, a spectrum can be obtained with high accuracy by keeping the moving speed of the movable mirror 450 constant. A control interferometer consisting of a laser light source 420, first and second laser reflectors 421 and 422, a beam splitter 440, a movable mirror 450, and a fixed mirror 460 is used to measure the moving speed of the movable mirror 450. In the control interferometer, the laser light emitted from the laser light source 420 is introduced onto the same optical path as the infrared light by the first laser light reflector 421, and passes through the same interference system (beam splitter 440, movable mirror 450, fixed mirror 460) as the infrared light to generate laser interference light. The laser interference light is taken out of the optical path of the infrared interference light by the second laser light reflector 422 and detected by a laser light detector 490. The moving speed of the movable mirror 450 is calculated based on the detected laser interference light.

[0017] 2 is a cross-sectional view of the infrared light source device 1. The infrared light source device 1 includes a ceramic heater 10, a cylindrical cover member 20, a cylindrical support member 30, and a cylindrical case 40.

[0018] The ceramic heater 10 includes a heater section 11 made of a ceramic material such as silicon nitride (SiN), a power line 12 for supplying power to the heater section 11, and a base 13 for supporting the heater section 11 and the power line 12. The base 13 of the ceramic heater 10 is fitted into the inner wall of the support member 30 on the base side, whereby the ceramic heater 10 is fixed to the support member 30.

[0019] The cover member 20 has a cylindrical shape with a closed end on the tip side and an open end on the base side. The cover member 20 includes a main body portion 21 and a fitting portion 22 arranged closer to the base side than the main body portion 21. The fitting portion 22 is formed to be thinner than the main body portion 21. The fitting portion 22 of the cover member 20 is fitted into the inner wall on the tip side of the support member 30, whereby the cover member 20 is fixed to the support member 30.

[0020] In a state where the ceramic heater 10 and the cover member 20 are fitted into the support member 30, the cover member 20 is disposed so as to cover the entire periphery of the heater portion 11 of the ceramic heater 10 without coming into contact with the heater portion 11.

[0021] A heating portion HA that generates heat by power supplied from a power line 12 is provided in a region on the tip side of the heater portion 11. When the heating portion HA is heated to about 1000° C., the heater portion 11 functions as an infrared light source that emits infrared light.

[0022] The case 40 is formed to cover the cover member 20. The inner wall of the base side of the case 40 is fitted into the outer wall of the support member 30, thereby fixing the case 40 to the support member 30. Infrared light emitted from the heat generating part HA of the ceramic heater 10 passes through the hole 21a of the cover member 20 and is emitted to the outside.

[0023] Fig. 3 is a plan view of the ceramic heater 10. As shown in Fig. 3, the heater portion 11 is formed in a rectangular plate shape. Fig. 3 shows the ceramic heater 10 viewed from a direction along the normal to the main surface 11a of the heater portion 11. Note that Fig. 2 above shows the infrared light source device 1 viewed from a direction along the main surface 11a of the heater portion 11.

[0024] The longitudinal dimension L1 of heater portion 11, the lateral dimension L2 of heater portion 11, and the thickness of heater portion 11 may be, for example, approximately 50 mm, approximately 5 mm, and approximately 1.5 mm, respectively.

[0025] Fig. 4 is a plan view of the cover member 20. Fig. 5 is a VV cross-sectional view of the cover member 20 in Fig. 4. As described above, the cover member 20 has a cylindrical shape with a closed end on the tip side and an open end on the base side.

[0026] The diameter din of the inner wall of the cover member 20 is set to a value (eg, about 8 mm) slightly larger than the dimension L2 (eg, about 5 mm) of the heater portion 11 of the ceramic heater 10 in the short side direction.

[0027] A hole 21a is formed in the body 21 of the cover member 20 to emit infrared light from the heat generating part HA of the ceramic heater 10 to the outside. The diameter of the hole 21a can be set to about 8 mm, for example. The thickness T of the body 21 of the cover member 20 can be set to about 1.5 mm, for example.

[0028] In the present embodiment, a pure aluminum-based material (aluminum with a purity of 99% or more) that has high heat reflectance and is not easily altered by heat radiation from the heater unit 11 is used as the material for the cover member 20. For example, an aluminum alloy in the A1000 series of JIS (Japanese Industrial Standards), more specifically, A1070 with an aluminum purity of 99.7% or more, or A1050 with an aluminum purity of 99.5% or more, is used as the material for the cover member 20.

[0029] In the infrared light source device 1 according to the present embodiment, the cover member 20 made of a pure aluminum-based material having a high thermal reflectance as described above is disposed so as to cover the entire periphery of the heater section 11. This allows the heat radiation emitted from the heater section 11 to be efficiently reflected back to the heater section 11 to heat the heater section 11, rather than confining the heat of the heater section 11 using a heat insulating material. Therefore, compared to the case where the periphery of the heater section 11 is covered with a heat insulating material such as porous ceramic (corresponding to the conventional structure), the thickness of the cover member 20 can be made thin to reduce the size of the infrared light source device 1 while maintaining the temperature of the heater section 11 at a target temperature (for example, about 1000°C) or higher. In addition, since pure aluminum-based materials are less expensive than heat insulating materials such as porous ceramic, the cost of the infrared light source device 1 can also be reduced.

[0030] Furthermore, in this embodiment, a pure aluminum-based material that has high thermal reflectance and is not easily denatured by heat (is not easily formed with an oxide film) is used as the material for the cover member 20. This makes it possible to minimize deterioration of the thermal reflectance of the cover member 20 over time.

[0031] The inventors of the present application conducted an experiment in which the power consumption of the ceramic heater 10 was kept constant, the heater was covered with covers made of various materials, and an infrared detector was used to confirm how much infrared light the heater was emitting (i.e., how hot the heater itself was).

[0032] When the cover material was made of ceramic (alumina), the heater temperature was lower because alumina has a high inherent emissivity.

[0033] When the cover material was stainless steel (SUS), the heater temperature was high at the beginning of the experiment because stainless steel has a high reflectance (i.e. low emissivity). However, over time, an oxide film gradually formed on the cover surface, causing the cover surface to turn black, which in turn reduced the reflectance of the stainless steel and gradually reduced the heater temperature.

[0034] Similarly, when the cover was made of stainless steel (SUS) and the inside wall of the cover was gold plated, the reflectivity of the gold plating was very high at the beginning of the experiment, causing the heater temperature to rise. However, over time the cover surface turned black and the heater temperature dropped.

[0035] When the cover material was stainless steel (SUS) and the inner wall of the cover was chrome plated, the heater temperature was lower because chrome has a lower reflectivity than gold or aluminum.

[0036] When the cover material was A6061 (an aluminum alloy with an aluminum purity of less than 99%), the heater temperature was high at the beginning of the experiment due to its high reflectivity, but the heater temperature gradually decreased due to the oxide coating of the alloy components added to the aluminum.

[0037] When the cover material was A1050 (aluminum alloy with an aluminum purity of 99.5% or more), the reflectivity was high, the heater temperature was maintained at a high value, and there was almost no effect of the oxide film, and no temperature drop over time was observed. From these experimental results, it can be seen that the best results can be obtained by using a pure aluminum-based material (aluminum with a purity of 99% or more) for the cover member 20 as in this embodiment.

[0038] Furthermore, in the infrared light source device 1 according to the present embodiment, the ceramic heater 10 and the cover member 20 are fitted into the support member 30, so that the cover member 20 can be easily and appropriately prevented from coming into contact with the heater section 11. That is, even if the heater section 11 is inclined with respect to the cover member 20 when the heater section 11 is inserted into the cover member 20, the cover member 20 can be fixed in a state where it does not come into contact with the heater section 11 by finally fitting it into the support member 30. As a result, even if the heater section 11 reaches 1000°C or higher, which is higher than the melting point of aluminum, 660°C, the temperature of the cover member 20 can be maintained lower than the melting point of aluminum, 660°C. As a result, the cover member 20 can be appropriately prevented from melting and deforming due to the heat from the heater section 11.

[0039] In addition, measures such as providing a separate metal cover for fixing around the heat insulating material, which is difficult to process finely, may be required to fix the heat insulating material without contacting the heater section 11. In contrast, in the infrared light source device 1 according to this embodiment, the material of the cover member 20 is aluminum, which is easy to process finely, so there is no need to provide a separate metal cover for fixing, and the structure of the infrared light source device 1 can be simplified.

[0040] As described above, in the present embodiment, the temperature of the heater section 11 (infrared light source) can be maintained at or above a target temperature, while the infrared light source device 1 can be made smaller and less expensive.

[0041] [Variations] In the above embodiment, the case where the material of the cover member 20 is pure aluminum-based has been described. However, the material of the cover member 20 is not necessarily limited to pure aluminum-based. For example, the material of the cover member 20 may be gold.

[0042] In addition, as long as the material of the inner wall of the cover member 20 is pure aluminum-based or gold, the material of the cover member 20 itself does not necessarily have to be pure aluminum-based or gold. For example, the material of the cover member 20 may be a material other than pure aluminum and gold, and pure aluminum-based or gold may be vapor-deposited on the inner wall of the cover member 20.

[0043] The material of the cover member 20 may be an aluminum alloy with a purity of less than 99%. However, in order to suppress deterioration due to an oxide film as described above, it is preferable that the purity of the aluminum alloy is as close to 99% as possible.

[0044] [Aspects] It will be understood by those skilled in the art that the above-described embodiment and its modifications are specific examples of the following aspects.

[0045] (Item 1) An infrared light source device according to one embodiment includes a heater that emits infrared light when heated, and a cover member that is disposed so as to cover the entire periphery of the heater without contacting the heater and has a hole formed therein for emitting the infrared light from the heater to the outside. The material of the inner wall of the cover member is aluminum or gold.

[0046] According to the infrared light source device described in paragraph 1, a cover member having an inner wall made of aluminum or gold, which has a high thermal reflectivity, is arranged to cover the entire periphery of the heater. This allows the inner wall of the cover member to efficiently reflect heat radiation from the heater back to the heater, thereby heating the heater. This allows the thickness of the cover member to be made thinner while maintaining the heater at a high temperature, compared to when a heat insulating material is used. As a result, the infrared light source device can be made smaller while maintaining the heater temperature at or above a target temperature.

[0047] (Item 2) In the infrared light source device described in Item 1, the material of the cover member is aluminum with a purity of 99% or more.

[0048] According to the infrared light source device described in paragraph 2, by using aluminum with a purity of 99% or more as the material of the cover member, the heat radiation from the heater can be efficiently reflected back to the heater to heat the heater. Furthermore, compared to using ceramic (alumina), stainless steel (SUS), or aluminum with a purity of less than 99% as the material of the cover member, it is possible to make it difficult for an oxide film to form on the surface of the cover member, which makes it easier to suppress deterioration of the heat reflectance of the cover member over time.

[0049] (Item 3) The infrared light source device according to item 1 or 2 further includes a support member into which the heater and the cover member are fitted. When the heater and the cover member are fitted into the support member, the cover member is disposed so as to cover the entire periphery of the heater without contacting the heater.

[0050] According to the infrared light source device described in the third aspect, by adopting a structure in which the heater and the cover member are fitted into the support member, it is possible to easily and appropriately prevent the cover member from coming into contact with the heater.

[0051] (Item 4) A Fourier transform infrared spectrophotometer according to one aspect includes the infrared light source device according to any one of items 1 to 3.

[0052] According to this Fourier transform infrared spectrophotometer, it is possible to realize a Fourier transform infrared spectrophotometer having a compact infrared light source device while maintaining the heater temperature at or above a target temperature.

[0053] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the description of the embodiments described above, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0054] 1 infrared light source device, 10 ceramic heater, 11 heater portion, 11a main surface, 12 power line, 13 base portion, 20 cover member, 21 main body portion, 21a hole, 22 fitting portion, 30 support member, 40 case, 400 interferometer chamber, 420 laser light source, 421 first laser light reflector, 422 second laser light reflector, 431a focusing mirror, 431b collimator mirror, 432 object mirror, 433 ellipsoidal mirror, 440 beam splitter, 450 movable mirror, 460 fixed mirror, 470 sample chamber, 480 infrared light detector, 490 laser light detector, HA heat generating portion.

Claims

1. a heater that emits infrared light when heated; a cover member disposed so as to cover the entire periphery of the heater without contacting the heater, the cover member having a hole formed therein for emitting infrared light from the heater to the outside; The material of the inner wall of the cover member is aluminum or gold, a support member into which the heater and the cover member are fitted, An infrared light source device, wherein when the heater and the cover member are fitted into the support member, the cover member is positioned so as to cover the entire periphery of the heater without contacting the heater and without there being any solid material between the cover member and the heater.

2. 2. The infrared light source device according to claim 1, wherein the material of the cover member is aluminum having a purity of 99% or more.

3. 3. A Fourier transform infrared spectrophotometer comprising the infrared light source device according to claim 1.

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