Concentration calculation device

Abstract

An object to be measured (P) adheres to a predetermined surface of a prism (105). A camera (111) captures an image of the predetermined surface. A mirror (106) rotates light from a light projection unit disposed in the vicinity of the camera (111) and causes the light to be incident on the prism (105) so as to be totally reflected on the predetermined surface. The mirror (107) causes light totally reflected and emitted from the prism (105) to be incident on a light receiving unit disposed in the vicinity of the camera (111). The housing (100) houses the light projection unit, the light receiving unit, the mirror (106), and the mirror (107). Collimation adjustment windows (121) and (122) are attached to positions in the housing (100) where the light projection unit and the light receiving unit can be checked.

Description

Concentration calculation device

[0001] The present invention relates to a concentration calculation device.

[0002] ATR (Attenuated Total Reflection) is one of the methods for optically measuring the concentration of a small amount of substance. In ATR, incident light from a light source is made to pass through a prism and totally reflected at the surface where the measurement object and the prism are in contact, and the reflected light is emitted. In total reflection, the incident light penetrates into the measurement object by the penetration depth and obtains the absorption information of the measurement object. Therefore, by measuring the emitted light, an absorption spectrum caused by the measurement object can be obtained.

[0003] A concentration calculation device using ATR calculates the concentration of the target substance from this absorption spectrum. Such a concentration measurement device is used in various fields, and in recent years, it is also used for measuring the concentration such as decontamination in an isolator. And in order to obtain an appropriate absorption spectrum in a concentration calculation device using ATR, it is preferable that the incident angle with respect to the prism is a predetermined angle or more.

[0004] As a technology of such a concentration calculation device, a technology has been proposed in which light emitted from a light source is made incident on a prism, and after total reflection, the light emitted from the prism is refracted in an optical path by a mirror and made incident on a detector to measure the concentration (for example, Patent Document 1). Also, a technology has been proposed in which light irradiated from a light source is condensed onto a hollow optical fiber by a collimating lens and made incident on a prism, and the reflected light is made incident on the collimating lens via the hollow optical fiber and input to a detector to perform concentration measurement (for example, Patent Document 2). Further, a technology has been proposed for a concentration calculation device using a collimating lens, in which the collimating lens is displaced in the optical axis direction to perform spherical aberration correction (for example, Patent Document 3).

[0005] Japanese Unexamined Patent Application Publication No. 2012-132745, Japanese Unexamined Patent Application Publication No. 2019-037752, Japanese Unexamined Patent Application Publication No. 2010-000254

[0006] However, in order to incident light on a prism at an angle greater than a certain angle, the device that illuminates the prism with light and the device that receives the light emitted from the prism must be positioned at a location where the angle of incidence on the prism is greater than a certain angle. A large space is required to position these devices, which results in a large size for the density imaging device. When performing density measurements in a narrow space such as an isolator, a compact size is required, but with conventional technology, it is difficult to miniaturize density calculation devices.

[0007] Furthermore, proper collimation is necessary for efficient concentration measurement, but when miniaturized, the collimating lens is usually placed very close to the prism, making this verification difficult. As described above, due to limitations on the installation location of the concentration measuring device and the difficulty in verifying collimation when miniaturized, it is difficult to improve convenience with conventional concentration calculation devices.

[0008] Furthermore, in the technique of measuring density by totally reflecting light emitted from a light source through a prism, refracting the optical path with a mirror, and then having it enter a detector, the collimating lens is not taken into consideration, making it difficult to easily verify collimation. Also, in the technique of focusing light with a collimating lens and having it enter a prism, and then having the reflected light enter the collimating lens to measure density, and in the technique of correcting spherical aberration by displacing the collimating lens in the optical axis direction, the verification of collimation is not taken into consideration. Therefore, regardless of the technique used, it is difficult to miniaturize the density calculation device and to easily verify collimation, making it difficult to improve the convenience of the density calculation device.

[0009] One aspect of the present invention is to improve convenience by enabling miniaturization of the concentration calculation device and facilitating collimation verification.

[0010] The density calculation device for one side surface has the following parts: A prism has a predetermined surface on which the object to be measured adheres. A camera photographs the predetermined surface. A first optical axis rotation unit rotates light from a light-emitting unit located near the camera so that it is incident on the prism so as to undergo total internal reflection at the predetermined surface. A second optical axis rotation unit causes the light emitted from the prism after total internal reflection to be incident on a light-receiving unit located near the camera. The housing houses the light-emitting unit, the light-receiving unit, the first optical axis rotation unit, and the second optical axis rotation unit. An inspection window is mounted in the housing at a position where the light-emitting unit and the light-receiving unit can be seen.

[0011] According to the present invention, convenience can be improved.

[0012] This figure shows a density calculation device including the external appearance of the ATR device. This is a configuration diagram of the ATR device according to the first embodiment. This figure shows an example of an anti-reflection measure. This is a perspective view of the optical system storage section. This figure shows the reflection of light on the prism surface when a collimating lens is not used. This is an enlarged view of the collimation adjustment mechanism. This figure shows the first adjustment procedure for collimation adjustment. This figure shows the second adjustment procedure for collimation adjustment. This figure shows the third adjustment procedure for collimation adjustment. This figure shows the collimation adjustment mechanism of a linearly arranged optical system. This is a configuration diagram of the ATR device according to the second embodiment. This figure shows the optical system according to the second embodiment. This is a schematic diagram for explaining ATR. This is a schematic diagram of the arrangement of mirrors and prisms in the ATR device according to the third embodiment. This is a configuration diagram of the ATR device according to the fourth embodiment. This is a cross-sectional view of the ATR device according to the fourth embodiment along line A-A'. This figure shows the optical path within the prism according to the fourth embodiment. This figure shows the optical system of the ATR device according to the fifth embodiment. This is a hardware configuration diagram of the arithmetic unit.

[0013] The embodiments of the concentration calculation device will be described below with reference to the drawings. The same elements will be denoted by the same reference numerals, and redundant explanations will be omitted as appropriate. Furthermore, each embodiment can be combined as appropriate within the bounds of consistency.

[0014] (First Embodiment) (Overall Configuration) Figure 1 is a diagram showing a concentration calculation device including the external appearance of the ATR device. In Figure 1, the components that are visible from the outside among the various components mounted on the ATR device 1 are shown as examples. Details of the inside of the ATR device 1 will be described later. The concentration calculation device 10 includes the ATR device 1 and the calculation device 2. The ATR device 1 is connected to the calculation device 2.

[0015] The ATR device 1 is a device that synchronizes the optical measurement of a substance to be used for concentration calculation by ATR with the imaging of the substance to be used for concentration calculation. The ATR device 1 has a housing 100 equipped with an optical system storage unit 120. The optical system storage unit 120 houses, for example, a prism 105. Furthermore, in this embodiment, the housing 100 houses a camera 111, a lens 112, a focus adjustment stage 113, ATR fibers 211 and 212, and a USB cable 213 for the camera 111, etc., in the parts other than the optical system storage unit 120.

[0016] The ATR device 1 uses a camera 111 to photograph the substance to be measured for concentration that is attached to the prism 105. The ATR device 1 also uses a mechanism that performs optical measurements using an ATR located in the optical system storage unit 120 to perform optical measurements of the substance to be measured for concentration that is attached to the prism 105.

[0017] For example, the ATR device 1 is installed inside the chamber of an isolator used in the manufacture of pharmaceuticals or clinical trials. The chamber is periodically decontaminated with hydrogen peroxide to remove microorganisms. The ATR device 1 performs optical measurements and imaging of the hydrogen peroxide used for decontamination that adheres to the prism 105.

[0018] The calculation unit 2 receives the results of optical measurements of the substance to be measured for concentration and image data of the captured image from the ATR device 1. The calculation unit 2 then uses the image data of the captured image to correct the absorption spectrum obtained from the optical measurement and calculates the concentration of the substance to be measured for concentration.

[0019] (ATR device) Figure 2 is a diagram of the configuration of an ATR device according to the first embodiment. The ATR device 1 includes a housing 100, a white light source 201, a spectrometer 202, an MPU (Micro Processing Unit) 203, and a white light source 204.

[0020] The optical system storage compartment 120 of the housing 100 houses the collimating lenses 101 and 103, the prism 105, and the mirrors 106, 107, and 114. In addition, the parts of the housing 100 other than the optical system storage compartment 120 house the XYZ stages 102 and 104, the camera 111, the lens 112, and the focus adjustment stage 113.

[0021] The white light source 201 is a light source that emits white light containing wavelengths absorbed by the target substance P. The white light source 201 irradiates light toward the ATR fiber 211. The irradiated light is sent to the collimating lens 101 via the ATR fiber 211.

[0022] The XYZ stage 102 is a mechanism for adjusting the relative position between the collimating lens 101 and the ATR fiber 211. For example, the XYZ stage 102 supports the end of the ATR fiber 211 that faces the collimating lens 101 in a movable state. The XYZ stage 102 and the end of the ATR fiber 211 are positioned near the camera 111 and the lens 112.

[0023] The XYZ stage 102 performs XY adjustment to align the center of the ATR fiber 211 with the center of the collimating lens 101, and Z adjustment to change the distance between them so that the light emitted from the collimating lens 101 becomes parallel light. In this embodiment, the XYZ stage 102 is positioned near the camera 111.

[0024] The collimating lens 101 is positioned near the camera 111 and lens 112. The collimating lens 101 receives light emitted from the ATR fiber 211. The light emitted from the ATR fiber 211 spreads radially due to the NA (Numerical Aperture) of the ATR fiber 211. Therefore, the collimating lens 101 receives the light emitted from the ATR fiber 211 and emits it as parallel light.

[0025] Here, the XYZ stage 102, the end of the ATR fiber 211, and the collimating lens 101 are examples of the "light projection unit." Also, the camera 111 and lens 112 together are examples of the "camera." The camera 111 and lens 112 photograph a predetermined surface of the prism 105. The light projection unit is positioned near the camera 111 and lens 112.

[0026] Furthermore, the collimating lens 101 is an example of a "first collimating lens." The end of the ATR fiber 211 supported by the XYZ stage 102 is an example of an "emission section." In other words, the first collimating lens converts the light emitted from the emission section into parallel light.

[0027] The mirror 106 is, for example, a half-mirror or a triangular prism. The mirror 106 rotates the light emitted from the collimating lens 101 by 90 degrees and directs it onto the prism 105. The position of the mirror 106 is adjusted so that the angle of incidence of the light incident on the prism 105, where the target substance P is attached, satisfies the total internal reflection condition at the surface of the prism 105, under the conditions of the concentration of the target substance P and the refractive index of the prism 105.

[0028] Furthermore, if the mirror 106 is a triangular prism or the like and does not allow light traveling in a straight line to pass through, it is detachably mounted to the optical system storage section 120 of the housing 100. For example, although not shown, the optical system storage section 120 according to this embodiment is provided with fixing screws for attaching and detaching the mirror 106. The mirror 106 is fixed to the optical system storage section 120 by these fixing screws, and the mirror 107 can be removed from the optical system storage section 120 by loosening the fixing screws 123.

[0029] Furthermore, if the mirror 106 is a half-mirror and allows light to pass through, the light transmitted through the mirror 106 will proceed towards the collimation adjustment window 121, which will be described later. If the light is reflected by the cover of the collimation adjustment window 121, the scattered light will be a cause of density errors. Therefore, in order to prevent deterioration of density characteristics due to reflection from the collimation adjustment window 121, it is preferable to provide an anti-reflection measure to the collimation adjustment window 121. The collimation adjustment window 121 will be described in detail later.

[0030] Figure 3 shows an example of an anti-reflection measure. In Figure 3, the collimating lens 101 and XYZ stage 102, etc., have been omitted for clarity of explanation.

[0031] For example, the light filtered from the ATR fiber 211 travels towards the mirror 106, which is a half-mirror, as shown in the optical path 54. Then, a portion of the light is reflected by the mirror 106 and travels along the optical path 55. Another portion of the light passes through the mirror 106 and travels towards the collimation adjustment window 121 as shown in the path 56. Therefore, as an anti-reflection measure, a black light absorber 52 is provided inside the housing 100 at the location where the collimation adjustment window 121 is positioned.

[0032] The black light absorber 52 absorbs light that has passed through the mirror 106. This suppresses the generation of scattered light from the collimation adjustment window 121. However, since the black light absorber 52 does not absorb 100% of the light, a small amount of scattered light is generated. If the effect of this small amount of scattered light cannot be ignored, the mounting surface of the black light absorber 52 can be angled using the base 51 as shown in Figure 3, preventing unabsorbed light from directly returning to the ATR fiber 211. The base 51 and the black light absorber 52 are removable. Furthermore, the effect of scattered light can be further suppressed by providing a black light absorber 53 inside the housing 100.

[0033] This mirror 106 is an example of a "first optical axis rotating unit." That is, the first optical axis rotating unit rotates the light from the light-emitting unit located near the camera 111 and lens 112 so that it is incident on the prism 105 in a predetermined plane for total internal reflection. The first optical axis rotating unit may also be detachable from the housing 100.

[0034] The prism 105 is manufactured from a material that satisfies the total internal reflection condition with respect to the target substance P. Figure 4 is a perspective view of the optical system housing. As shown in Figure 4, one surface of the prism 105 is exposed to the outside from the housing 100. The target substance P for concentration measurement adheres to the surface of the prism 105 that is exposed to the outside. This surface to which the target substance P is attached is an example of a "predetermined surface". In other words, the target substance P to be measured adheres to the predetermined surface of the prism 105.

[0035] Returning to Figure 2, the explanation continues. The prism 105 receives incident parallel light emitted from the mirror 106. The incident light to the prism 105 travels toward the surface exposed to the outside of the prism 105 with a predetermined angle of incidence and is reflected by the surface of the prism 105 attached to the target substance P. The light that irradiates the portion of the incident light in which the target substance P is present generates evanescent light within the target substance P and is reflected as light containing the absorption information of the target substance P. Also, the light that irradiates the portion of the incident light other than the portion in which the target substance P is present is reflected as light that does not contain the absorption information of the target substance P. The incident light is reflected at least once at the surface in contact with the prism 105 in which the target substance P is present. The angle of incidence is adjusted so as to satisfy the total internal reflection condition at the surface of the prism 105 under the conditions of the concentration of the target substance P and the refractive index of the prism 105.

[0036] The reflected light is emitted from the prism 105. The light emitted from the prism 105 contains absorbance information of the target substance P that is within the depth range of the evanescent light penetration.

[0037] Mirror 107 is, for example, a half-mirror or a triangular prism. Mirror 107 rotates the light emitted from prism 105 by 90 degrees and directs it onto collimating lens 103.

[0038] If the mirror 107 is a triangular prism or the like and does not allow light traveling in a straight line to pass through, it is detachably mounted to the optical system storage section 120 of the housing 100. For example, as shown in Figure 4, the optical system storage section 120 according to this embodiment is provided with a fixing screw 123 for attaching and detaching the mirror 107. The mirror 107 is fixed to the optical system storage section 120 by the fixing screw 123, and the mirror 107 can be removed from the optical system storage section 120 by loosening the fixing screw 123.

[0039] Furthermore, if the mirror 107 is a half-mirror, it is preferable that, as with the case of the mirror 106, an anti-reflective measure as shown in Figure 3 is applied to the collimation adjustment window 122.

[0040] This mirror 107 is an example of a "second optical axis rotating part." That is, the second optical axis rotating part directs the light emitted from the prism 105 after total internal reflection into a light-receiving part located near the camera 111 and lens 112. The second optical axis rotating part may also be detachable from the housing 100.

[0041] The XYZ stage 104 is a mechanism for adjusting the relative position between the collimating lens 103 and the ATR fiber 212. For example, the XYZ stage 104 supports the end of the ATR fiber 212 that faces the collimating lens 103 in a movable state. The XYZ stage 104 and the end of the ATR fiber 212 are positioned near the camera 111 and the lens 112.

[0042] The collimating lens 103 is positioned near the camera 111 and lens 112. The collimating lens 103 receives light emitted from the mirror 107. The collimating lens 103 then focuses the emitted light and irradiates the ATR fiber 212. The irradiated light is sent to the spectrometer 202 via the ATR fiber 212.

[0043] Here, the XYZ stage 104, the end of the ATR fiber 212, and the collimating lens 103 are examples of a "light receiving part". Further, the collimating lens 103 is an example of a "second collimating lens". And the end of the ATR fiber 212 supported by the XYZ stage 104 is an example of an "incident part". That is, the second collimating lens condenses the light emitted from the prism 105 and inputs it to the incident part.

[0044] The housing 100 stores a light projecting part, a light receiving part, a first optical axis rotating part, and a second optical axis rotating part.

[0045] The spectroscope 202 has a wavelength range including the wavelength absorbed by the target substance P and has a measurement speed that can follow the concentration change. The spectroscope 202 measures an absorption spectrum. And the spectroscope 202 transmits the measured absorption spectrum to the arithmetic unit 2.

[0046] In addition, collimating adjustment windows 121 and 122 are provided in the optical system storage part 120. Dust-proof covers are attached to the collimating adjustment windows 121 and 122, respectively. For example, the collimating adjustment windows 121 and 122 are attached in the state shown in FIG. 3.

[0047] And by removing the dust-proof covers from the collimating adjustment windows 121 and 122, openings that enable visual recognition of the inside of the optical system storage part 120 are formed. Here, the dust-proof covers and the openings are collectively referred to as the collimating adjustment windows 121 and 122, but hereinafter, the openings may be referred to as the collimating adjustment window 121 or 122. The collimating adjustment windows 121 and 122 are mechanisms for adjusting the collimation of the collimating lens 101 and confirming that it is operating properly.

[0048] Returning to FIG. 2, the description will be continued. The collimation adjustment window 121 is arranged in the direction in which the light emitted from the collimation lens 101 travels straight. By using the collimation adjustment window 121 with the mirror 106 being a half mirror or in the state where the mirror 106 is removed, it is possible to confirm whether the light emitted from the collimation lens 101 is parallel light, that is, whether it is collimated. The user can adjust the collimation of the collimation lens 101 by the XYZ stage 102 while checking the light emitted from the collimation lens 101 using the collimation adjustment window 121.

[0049] The collimation adjustment windows 121 and 122 are examples of a "confirmation window". That is, the confirmation window is attached at a position where the light projecting part and the light receiving part in the housing 100 can be confirmed.

[0050] In particular, the collimation adjustment window 121 is an example of a "first confirmation window". That is, the first confirmation window is arranged in the direction in which the light emitted from the emission part and passing through the collimation lens 101 travels straight. Also, when the mirror 106 is a half mirror, the first confirmation window is arranged in the direction in which the light emitted from the emission part and passing through the first collimation lens passes through the first optical axis rotation part and travels straight.

[0051] The collimation adjustment window 122 is arranged in the direction in which the light emitted from the collimation lens 101 travels straight. By using the collimation adjustment window 122 with the mirror 107 being a half mirror or in the state where the mirror 107 is removed, it is possible to confirm whether the light emitted from the collimation lens 101 is parallel light, that is, whether it is collimated. The user can adjust the collimation of the collimation lens 101 by the XYZ stage 102 while checking the light emitted from the collimation lens 101 using the collimation adjustment window 122.

[0052] The collimation adjustment window 122 is an example of a "second confirmation window." That is, the second confirmation window is positioned in the direction in which light emitted from the emission section and passing through the collimation lens 101 travels in a straight line. Also, if the mirror 107 is a half mirror, it is positioned in the direction in which light emitted from the emission section, passing through the first collimation lens and rotated in the first optical axis rotation section, passes through the second optical axis rotation section and travels in a straight line.

[0053] The mirror 114 is, for example, a triangular prism. The mirror 114 rotates the light that forms the image of the prism 105, to which the target substance P is attached, by 90 degrees and directs it towards the lens 112.

[0054] The focus adjustment stage 113 is a mechanism for adjusting the focus of the camera 111. The focus adjustment stage 113 adjusts the focus of the camera 111 so that it matches the surface of the prism 105 to which the target substance P is attached.

[0055] Lens 112 is, for example, a telecentric lens developed to measure the dimensions of a target substance P. Here, dimensions refer to information including the individual area and perimeter of the target substance P attached to the prism 105.

[0056] However, the lens 112 is not limited to a telecentric lens; for example, a wide-angle lens may be used. Since wide-angle lenses have a shorter barrel length than telecentric lenses, it is possible to miniaturize the housing 100 of the ATR device 1.

[0057] A lens 112 is attached to the camera 111. The optical axis of the camera 111 is directed towards the mirror 114 via the lens 112. The light that forms the image of the surface of the prism 105 to which the target substance P is attached is rotated by the mirror 114 and incident on the camera 111 via the lens 112. As a result, the camera 111 captures an image of the prism 105 to which the target substance P is attached. The image captured by the camera 111 is sent to the computing unit 2 via the MPU 203. Since the camera 111 generates heat, it may be covered with a cooling jacket to suppress the temperature inside the housing 100.

[0058] The white light source 204 is the light source for the camera 111 to take photographs. The light emitted from the white light source 204 is transmitted through the fiber 214 and used for the camera 111 to photograph the prism 105 to which the target substance P is attached.

[0059] The MPU 203 is connected to the camera 111 via a USB cable 213. The MPU 203 controls the camera 111's imaging. For example, the MPU 203 receives instructions on the imaging timing from the arithmetic unit 2 and causes the camera 111 to take an image at the specified timing. Alternatively, the MPU 203 may be mounted on the arithmetic unit 2.

[0060] The computing device 2 is connected to the spectrometer 202 and camera 111 by wire or wireless connection and is capable of communicating with the spectrometer 202 and camera 111. The computing device 2 is, for example, a computer such as a personal computer or a server device. The computing device 2 has a processor such as a CPU (Central Processing Unit) and memory which is a storage device.

[0061] The computing device 2 receives image data captured by the camera 111 from the camera 111. The computing device 2 performs image processing, such as image feature calculation processing, on the received image data to make it possible to distinguish between regions where the target substance P exists and regions where the target substance does not exist. The computing device 2 then analyzes the image data and calculates the area ratio, which is the ratio of the area of ​​the region containing the droplet to the area of ​​the region struck by the incident light of the total internal reflection measurement method. Here, if the area of ​​the region struck by the incident light is equal to the area of ​​the region captured by the camera 111, the computing device 2 can use the area of ​​the region captured by the camera 111 as the area of ​​the region struck by the incident light.

[0062] Here, even if a standard wide-angle lens is used for lens 112, the calculation unit 2 can calculate the coverage ratio using a similar calculation method, provided that the height of the target substance P is low. The information obtained from the image data for density calculation is the coverage ratio, which is the area ratio of the portion of the target substance P that is in contact with the prism 105. Regarding this coverage ratio, since both the portion where the target substance P is attached and the portion where it is not attached are magnified equally, it is considered that a value similar to that obtained when using a telecentric lens can be obtained even when using a wide-angle lens for lens 112.

[0063] Furthermore, when a standard wide-angle lens is used for lens 112, it is preferable to perform dimensional correction based on the location in the image in order to measure the dimensions of the target substance P. Therefore, when a wide-angle lens is used for lens 112, the calculation unit 2 can measure the dimensions of the target substance P by adding a trapezoidal correction process on a plane that corrects for spread from the center outwards.

[0064] Next, the arithmetic unit 2 calculates a correction value by providing one or more parameters, including the calculated area ratio, to a pre-given formula. The correction value is a value that has a negative correlation with the area ratio, and the smaller the area ratio, the greater the degree of correction.

[0065] Next, the computing device 2 acquires the absorption spectrum measured by the total internal reflection method from the spectrometer 202 via communication. Then, by using the calculated correction value, the computing device 2 can obtain an absorption spectrum similar to that obtained when the target substance P is present throughout the entire prism 105.

[0066] Furthermore, when a telecentric lens that measures the dimensions of the target substance P is used as the lens 112, the calculation device 2 can obtain height information of the target substance P by performing a luminance analysis of the target substance P. Therefore, the calculation device 2 can calculate a correction value taking into account the height information of the target substance P. This makes it possible to improve the accuracy of concentration calculation when the target substance P attached to the prism 105 is small.

[0067] The arithmetic unit 2 calculates the absorbance spectrum of the target substance P by correcting the received absorbance spectrum with a calculated correction value. For example, the arithmetic unit 2 calculates the absorbance spectrum of the target substance P by multiplying the absorbance spectrum by a correction value. Subsequently, the arithmetic unit 2 stores the concentration data, including the calculated absorbance spectrum of the target substance P, in a storage device that is not shown. Alternatively, the arithmetic unit 2 may display the calculated concentration data on a monitor or the like (not shown) and provide it to the user.

[0068] This calculation device 2 is an example of a "concentration calculation unit." In other words, the concentration calculation unit corrects the absorption spectrum measured based on the light collected by the light receiving unit, based on the image captured by the camera 111 and lens 112, and calculates the concentration of the object to be measured based on the corrected absorption spectrum.

[0069] In this embodiment, the area ratio was calculated based on image data that had been smoothed by the arithmetic unit 2. However, the arithmetic unit 2 may calculate the area ratio for each image data and then perform the smoothing process on the calculated area ratio.

[0070] (Collimation Adjustment) Figure 5 shows the reflection of light on the prism surface when a collimating lens is not used. Now, referring to Figure 5, we will explain the effect of collimation on the measurement value. Here, we will explain using an incident element 31 and a light-receiving element 32, and the light emitted from the incident element 31 spreads radially.

[0071] Absorption measurement is possible even when the light entering the prism 105 from the incident element 31 is spread out. However, as shown in Figure 5, the light spreads out even within the prism 105, so the amount of light that can be received by the photodetector 32 decreases. Furthermore, if the photodetector 32 is sufficiently large, or if a sufficiently large focusing lens is used to focus the light onto the photodetector 32, it is possible to suppress the decrease in the amount of light that can be received by the photodetector 32. However, if the incident angle to the surface of the prism 105 is spread from Θ1 to Θ3, a difference will occur in the penetration depth of the evanescent wave, creating a distribution in the optical path length, which may reduce the measurement accuracy.

[0072] From the above, it is important to collimate the light emitted from the ATR fiber 211 using the collimating lens 101 in order to improve the accuracy of measuring the concentration of the target substance P. Furthermore, in order to further improve the accuracy of concentration measurement, it is preferable that the collimation is performed accurately.

[0073] Figure 6 is an enlarged view of the collimation adjustment mechanism. Next, the adjustment of the collimation will be explained with reference to Figure 6. The light emitted from the ATR fiber 211 spreads radially due to the NA of the ATR fiber 211. The collimation lens 101 makes the radially spreading light emitted from the ATR fiber 211 into parallel light.

[0074] By aligning the central axis of the collimating lens 101 with the optical axis of the ATR fiber 211 and illuminating the collimating lens 101 from an appropriate distance, collimated light can be output. Here, collimated light is a cylindrical, parallel beam of light. At this time, the XYZ stage 102 adjusts the position of the end of the ATR fiber 211 and the collimating lens 101. By precisely adjusting the position of the end of the ATR fiber 211 and the collimating lens 101, the desired collimated light can be obtained.

[0075] The collimation adjustment in the ATR device 1 according to this embodiment will be described below. Collimation adjustment in the ATR device 1 is performed according to the following first to third adjustment procedures. Here, the explanation will be given for the case where the user of the concentration calculation device 10 makes the adjustment.

[0076] Figure 7 shows the first adjustment procedure for collimation adjustment. The first adjustment procedure for collimation adjustment according to this embodiment will be explained with reference to Figure 7.

[0077] The user removes the dust cover of the collimation adjustment window 121 from the optical system storage section 120 of the housing 100 to form an opening (step S101).

[0078] Next, the user loosens the fixing screws and removes the mirror 106 from the optical system storage section 120 of the housing 100 (step S102).

[0079] Furthermore, the user positions the beam profiler 300, for example, in the direction of propagation of the light emitted from the collimating lens 101 (step S103). In this state, light is emitted from the ATR fiber 211 as shown in the optical path R11. The light emitted from the ATR fiber 211 passes through the collimating lens 101 and through the optical path R12 before being incident on the beam profiler 300.

[0080] Therefore, the user moves the beam profiler 300 back and forth (step S104) and adjusts the optical axis with the XYZ stage 102 so that the position and size of the optical image do not change at any position (step S105).

[0081] After completing the optical axis adjustment, the user attaches the mirror 106 to the optical system storage compartment 120 of the housing 100 and secures it with fixing screws (step S106). The user also attaches the dust cover of the collimation adjustment window 121 to the optical system storage compartment 120 of the housing 100.

[0082] Figure 8 shows the second adjustment procedure for collimation adjustment. The second adjustment procedure for collimation adjustment according to this embodiment will be explained with reference to Figure 8.

[0083] The user removes the dust cover of the collimation adjustment window 122 from the optical system storage section 120 of the housing 100 to form an opening (step S201).

[0084] Next, the user loosens the fixing screws and removes the mirror 107 from the optical system storage section 120 of the housing 100 (step S202).

[0085] Furthermore, the user positions the beam profiler 300, for example, in the direction of travel of the light emitted from the collimating lens 101 after it has been rotated by the mirror 107 (step S203). In this state, light is emitted from the ATR fiber 211 as shown in optical path R21. After passing through the collimating lens 101, the light emitted from the ATR fiber 211 is rotated by the mirror 106 as shown in optical path R22 and then incident on the beam profiler 300.

[0086] Therefore, the user moves the beam profiler 300 back and forth to confirm that the position and size of the optical image do not change at any position (step S204).

[0087] After confirmation, the user attaches the mirror 107 to the optical system storage compartment 120 of the housing 100 and secures it with fixing screws (step S205). The user also attaches the dust cover of the collimation adjustment window 122 to the optical system storage compartment 120 of the housing 100.

[0088] Figure 9 shows the third adjustment procedure for collimation adjustment. The third adjustment procedure for collimation adjustment according to this embodiment will be explained with reference to Figure 9.

[0089] The user attaches the power meter 301 to the ATR fiber 212 (step S301). In this state, light is emitted from the ATR fiber 211 as shown in the optical path R31. After passing through the collimating lens 101, the light emitted from the ATR fiber 211 is rotated by the mirror 106 and then by the mirror 107 as shown in the optical path R32. Subsequently, the light passes through the collimating lens 103 and proceeds as shown in the optical path R33, passes through the ATR fiber 212, and is incident on the power meter 301.

[0090] Next, the user adjusts the XYZ stage 104 so that the power meter 301 is at its maximum (step S302).

[0091] Here, the above first to third adjustment procedures are for cases where mirrors 106 and 107 are not half-mirrors. If mirrors 106 and 107 are half-mirrors and are provided with a base 51 and black light absorber 52, etc. as anti-reflection measures as shown in Figure 3, then instead of removing and installing mirrors 106 and 107, the base 51 and black light absorber 52, etc. are removed and installed.

[0092] (Comparison) Figure 10 shows the collimation adjustment mechanism of a linearly arranged optical system. Now, referring to Figure 10, the difference between the collimation adjustment mechanism of the ATR device 1 according to this embodiment and the collimation adjustment mechanism of a linearly arranged optical system will be explained.

[0093] As shown in state 311 of Figure 10, it is also possible to arrange the optical instruments in a straight line without rotating the light with mirrors 106 and 107. In this configuration shown in state 41, the light emitted from the white light source 201 is made into parallel light by the collimating lens 101, then totally reflected by the surface of the prism 105 to which the target substance P is attached, and then passed through the collimating lens 103 and incident on the spectrometer 202. Then, an absorption spectrum can be obtained with the spectrometer 202, and the concentration of the target substance P can be measured.

[0094] Furthermore, by removing the dust covers 313 and 314 and placing the collimation adjustment mirror 315 in the optical path of the light emitted from the collimation lens 101, as shown in state 312, the light emitted from the collimation lens 101 can be incident on the beam profiler 300. Therefore, it is possible to adjust the collimation even in a configuration with a linearly arranged optical system.

[0095] However, when optical instruments are arranged linearly, the collimating lenses 101 and 103, or the XYZ stages 102 and 104, must be placed at a distance from the camera 11 in order to cause light to be incident at an angle of incidence that results in total internal reflection on the surface of the prism 105. Therefore, when using a linearly arranged optical system, the optical path length during density measurement becomes long. If the optical path length of the density measurement value is long, it becomes difficult to maintain the collimated state all the way to the output side, which may reduce the accuracy of density measurement. Therefore, in order to improve the accuracy of density measurement, it is preferable to arrange the XYZ stages 102 and 104 near the camera 111, as in this embodiment, to reduce their size and shorten the optical path length.

[0096] (Effects) As described above, in the density calculation device 10 according to this embodiment, the XYZ stage 102 supporting the end of the ATR fiber 211 and the XYZ stage 104 supporting the end of the ATR fiber 212 are arranged near the camera 111 and the lens 112. Light emitted from the ATR fiber 211 passes through the collimating lens 101, is rotated 90 degrees by the mirror 106, and is incident on the prism 105 where it undergoes total internal reflection. Then, light emitted from the prism 105 is rotated 90 degrees by the mirror 107, passes through the collimating lens 103, and is incident on the ATR fiber 212. Furthermore, the collimation by the collimating lens 101 is adjusted and confirmed using the collimation adjustment windows 121 and 122.

[0097] This allows for a reduction in the size of the housing 100 of the ATR device 1, and also facilitates the adjustment and verification of collimation. Therefore, it is possible to improve the convenience of the concentration calculation device 10.

[0098] (Second Embodiment) Next, an ATR device 1 according to the second embodiment will be described. Figure 11 is a configuration diagram of the ATR device according to the second embodiment. In the following description, the functions of each part, which are the same as in the first embodiment, will be omitted. In Figure 11, the camera 111, lens 112, and focus adjustment stage 113, etc., have been omitted.

[0099] As shown in Figure 11, the ATR apparatus 1 according to this embodiment has a white light source 201 and a spectrometer 202 arranged inside the housing 100.

[0100] The white light source 201 is supported by the XYZ stage 102. The XYZ stage 102 adjusts the white light source 201 so that its optical axis is centered on the collimating lens 101. The XYZ stage 102 also adjusts the white light source 201 so that the emitted light becomes parallel light after passing through the collimating lens 101. This white light source 201, XYZ stage 102, and collimating lens 101 constitute an example of a "light-emitting unit".

[0101] The spectrometer 202 is supported by the XYZ stage 104. The spectrometer 202 is adjusted to a position where the light focused by the collimating lens 103 forms an image at the focal point. This spectrometer 202, XYZ stage 104, and collimating lens 103 constitute an example of a "light-receiving unit".

[0102] Here, the white light source 201 and the spectrometer 202 generate heat. Therefore, it is preferable to provide a cooling mechanism 220 for cooling the inside of the housing 100. The cooling mechanism 220 may use a gas such as air as a refrigerant, or a liquid such as water as a refrigerant.

[0103] Figure 12 is a diagram showing the optical system according to the second embodiment. Referring to Figure 12, the optical processing in the optical system according to the second embodiment will be described in detail. Light emitted from the white light source 201 passes through the optical path R1 and is incident on the spectrometer 202.

[0104] A white light source 201, supported by an XYZ stage 102, emits light. The light emitted from the white light source 201 spreads radially and enters the collimating lens 101. The collimating lens 101 condenses the incident light into parallel light. The parallel light from the collimating lens 101 is rotated by the mirror 106 and enters the prism 105, where it undergoes total internal reflection at its surface.

[0105] Light that has undergone total internal reflection at the surface is emitted from the prism 105, rotated by the mirror 107, and incident on the collimating lens 103. The collimating lens 103 focuses the incident light and directs it into the spectrometer 202, which is supported by the XYZ stage 104.

[0106] (Effects) As described above, the ATR apparatus 1 according to this embodiment performs ATR measurements using a white light source 201 and a spectrometer 202 arranged in a housing 100. Thus, even with a configuration in which the white light source 201 and spectrometer 202 are arranged inside the housing 100, ATR measurements can be performed. Furthermore, by arranging the white light source 201 and spectrometer 202 inside the housing 100, it is possible to reduce the overall size of the concentration calculation device 10. Therefore, the convenience of the concentration calculation device 10 can be further improved.

[0107] (Third Embodiment) Next, an ATR device 1 according to the third embodiment will be described. In the ATR device 1 according to this embodiment, the prism 105 is a hemisphere. In the following description, the functions of each part, which are the same as in the first embodiment, will be omitted.

[0108] Figure 13 is a schematic diagram illustrating ATR. Figure 13 shows the state in which the target material 402 has undergone total internal reflection of light by a prism 401 in contact with its surface. In Figure 13, dp is the penetration depth of the evanescent light, and θ is the angle of incidence of the incident light.

[0109] In absorbance measurements using ATR, the absorbance of the target substance 402 is determined using the emitted light containing absorbance information of the target substance 402 that is within the range of dp, which is the penetration depth of evanescent light. Absorbance and dp are proportional. dp is expressed by the following formula (1).

[0110]

[0111] As shown in equation (1), dp can be expressed as a function of Θ. When dp is shorter than the thickness of the target substance 402, the absorbance increases by decreasing the angle of incidence Θ. Conversely, when dp becomes greater than the thickness of the target substance 402, the absorbance stops changing. Thus, there is a correlation between the angle of incidence Θ and the thickness of the target substance 402. From this, it is possible to improve the accuracy of concentration measurement by adjusting the angle of incidence to increase the absorbance under the condition that dp falls within the thickness of the target substance 402.

[0112] Figure 14 is a schematic diagram of the arrangement of mirrors and prisms in an ATR device according to the third embodiment. In the ATR device 1 according to this embodiment, mirrors 106 and 107 and a prism 105 are arranged as shown in Figure 14.

[0113] Mirrors 106 and 107 are adjustable in angle. In the ATR device 1, changing the angle of mirror 106 makes it possible to direct the rotated light towards the center of prism 105. Similarly, in the ATR device 1, changing the angle of mirror 107 makes it possible to direct the reflected light from prism 105 towards collimating lens 103.

[0114] As shown in the optical path R2, light rotated by mirror 106 enters prism 105 and undergoes total internal reflection on the surface of prism 105. The light emitted from prism 105 is then rotated by mirror 107 and enters collimating lens 103.

[0115] One might consider a configuration where the angle of incidence of the light incident on a plate-shaped prism is changed. However, in that case, changing the angle would cause the angle of incidence to no longer be perpendicular to the prism, making it difficult to accurately focus the light to the desired position. In contrast, when a hemispherical prism 105 is used, the angle of incidence of the light incident toward the center is always perpendicular to the plane of incidence, making it possible to accurately focus the light to the center of the prism 105. Therefore, even if the angle of incidence on the prism 105 is changed, the deterioration of the accuracy of the density measurement can be suppressed.

[0116] The calculation device 2 can change the rotation angle of the mirror 106 in various ways and obtain absorption spectra corresponding to each rotation angle from the light incident on the spectrometer 202. The calculation device 2 may then calculate the average thickness of the target substance P using the absorption spectra corresponding to each rotation angle.

[0117] Furthermore, in order to photograph the surface of the prism 105 to which the target substance P is attached using the camera 111, it is preferable to flatten a certain area on the spherical side of the prism 105.

[0118] Thus, the rotation angle of the first optical axis rotation unit may be adjustable. Furthermore, the prism 105 can be semi-spherical, with the spherical surface being a predetermined surface to which the target substance P adheres. Also, the density calculation unit is an example of an average thickness calculation unit. That is, the average thickness calculation unit may calculate the average thickness of the object to be measured based on the light collected by the light receiving unit obtained by changing the rotation angle of the first optical axis rotation unit.

[0119] (Effects) As described above, in the ATR apparatus 1 according to this embodiment, the prism 105 is hemispherical, and the incident angle of the light incident toward the center of the prism 105 can be changed. This makes it possible to increase the absorbance by adjusting the incident angle while keeping the depth of the evanescent light less than or equal to the thickness of the target substance P, thereby improving the accuracy of concentration measurement. Therefore, the convenience of the concentration calculation device 10 can be further improved.

[0120] (Fourth Embodiment) Next, the ATR device 1 according to the fourth embodiment will be described. Figure 15 is a configuration diagram of the ATR device according to the fourth embodiment. Figure 16 is a cross-sectional view of the ATR device according to the fourth embodiment along line segment A-A'. Figure 16 shows the cross-section of the ATR device 1 along line segment A-A' in Figure 15. In the following description, the functions of each part, as in the first embodiment, will not be explained.

[0121] The ATR apparatus 1 according to this embodiment has a hemispherical prism 105. The hemispherical prism 105 is positioned so that its planar side faces the mirrors 106 and 107 that irradiate the incident light. That is, the prism 105 can be semi-spherical, with its cross-section being a predetermined surface to which the target substance P adheres.

[0122] Figure 17 shows the optical path within a prism according to the fourth embodiment. As shown in the optical path R3 in Figure 17, light is incident on the prism 105 at a 90-degree angle to the plane. In the prism 105, at a position symmetrical to the center of the circle forming the plane, the light is emitted in a direction rotated 180 degrees with respect to the incident position, i.e., at a 90-degree angle to the bottom surface of the hemisphere. Therefore, angle adjustment of the light emitted from the prism 105 is unnecessary.

[0123] In the ATR device 1 according to this embodiment, as shown in Figure 17, by injecting light into the arc portion formed by the spherical surface of the prism 105, the light is repeatedly reflected in the arc portion as shown in the optical path R3 and emitted from the emission position. Here, since the absorbance signal intensity is proportional to the number of reflections, the ATR device 1 according to this embodiment has the potential to improve the signal-to-noise ratio.

[0124] As shown in Figures 15 and 16, the mirror 106 is positioned opposite the plane of the prism 105. The mirror 106 rotates the light that has passed through the collimating lens 101 by 90 degrees so that it is incident on the plane of the prism 105 at a 90-degree angle.

[0125] The collimation adjustment window 121 is positioned in the direction of light emission from the ATR fiber 211.

[0126] Furthermore, in this embodiment, a removal cover 124 for removing the mirror 106 is provided in the housing 100 at a location where the user can reach the mirror 106. The user can remove the removal cover 124 from the housing 100 and then remove the mirror 106 from the housing 100.

[0127] Mirror 107, like mirror 106, is positioned opposite the plane of prism 105. Mirror 107 receives the reflected light emitted from mirror 106 and reflected by prism 105. Mirror 107 then rotates the light incident from prism 105 by 90 degrees and directs it toward collimating lens 103.

[0128] The collimation adjustment window 122 is positioned in the direction of light emission from the prism 105. The collimation adjustment window 122 also serves as a removable cover for the mirror 107. That is, the user can remove the dust cover of the collimation adjustment window 122 from the housing 100 and then remove the mirror 107 from the housing 100.

[0129] (Effects) As described above, in the ATR device 1 according to this embodiment, the prism 105 is hemispherical, and light is incident on the plane of the prism 105 at a 90-degree angle. In this way, it is possible to calculate the concentration even when using a hemispherical prism 105. Furthermore, by reflecting the light multiple times off the spherical surface of the prism 105 and then emitting it, it is possible to improve the accuracy of the concentration measurement. Therefore, the convenience of the concentration calculation device 10 can be further improved.

[0130] (Fifth Embodiment) Next, an ATR device 1 according to the fifth embodiment will be described. Figure 18 is a diagram showing the optical system of the ATR device according to the fifth embodiment. In the following description, the functions of each part, which are the same as in the first embodiment, will not be described.

[0131] In each of the embodiments described above, the concentration calculation device 10 has a housing 100 containing the components used for measurement, which is installed for concentration measurement and performs concentration calculation. Therefore, there is a risk that the heat generated by the components used for measurement may affect the object being measured.

[0132] Therefore, in the concentration calculation device 10 according to this embodiment, the prism 105 is arranged to be exposed inside the device 400 that performs concentration measurement using the flange 403, as shown in Figure 18.

[0133] Furthermore, components other than the prism 105 are placed outside the apparatus 400. For example, as shown in Figure 18, the ATR fibers 211 and 212, collimating lenses 101 and 103, XYZ stages 102 and 104, and mirrors 106 and 107 are placed outside the apparatus 400. Although not shown, the white light source 201, spectrometer 202, camera 111, lens 112, focus adjustment stage 113 and mirror 114, etc., are also placed outside the apparatus 400.

[0134] In this manner, the prism 105, camera 111 and lens 112, and housing 100 are positioned outside the environment where the object to be measured exists. However, a predetermined surface of the prism 105 to which the target substance P, which is the object to be measured, adheres is exposed within the environment where the object to be measured exists.

[0135] As described above, in this embodiment of the concentration calculation device 10, all components are arranged outside the device 400, except for the prism 105 which is exposed to the device 400 that performs concentration measurement. This makes it easier to cool each component and reduces the thermal impact on the device. Therefore, the convenience of the concentration calculation device 10 can be further improved.

[0136] (System) The processing procedures, control procedures, specific names, and various data and parameters shown in the above documents and drawings may be changed at will unless otherwise specified. Furthermore, each embodiment can be used in combination with others.

[0137] Furthermore, the components of each illustrated device are functionally conceptual and do not necessarily need to be physically configured as shown. In other words, the specific forms of distribution and integration of each device are not limited to those shown. That is, all or part of them can be functionally or physically distributed and integrated in any unit according to various loads and usage conditions.

[0138] Furthermore, each processing function performed by each device may be implemented, in whole or in part, by a CPU (Central Processing Unit) and a program executed by that CPU, or by wired logic hardware.

[0139] (Hardware) Next, an example of the hardware configuration of the arithmetic unit 2 will be described. Figure 19 is a hardware configuration diagram of the arithmetic unit. As shown in Figure 19, the arithmetic unit 2 has a processor 91, memory 92, HDD (Hard Disk Drive) 93, and communication device 94. The processor 91 is connected to the memory 92, HDD 93, and communication device 94 via a bus.

[0140] The communication device 94 is a network interface card or the like, and is used for communication with other devices. For example, the communication device 94 relays communication between the processor 91 and the spectrometer 202 and MPU 203.

[0141] HDD93 is an auxiliary storage device. HDD93 can store, for example, captured image data, measured absorbance spectrum information, and concentration calculation results. HDD93 also stores various programs, including programs for realizing the functions of the arithmetic unit 2 as illustrated in Figure 1.

[0142] The processor 91 reads various programs stored in the HDD 93, loads them into the memory 92, and executes them. This allows the processor 91 to perform the functions of the arithmetic unit 2, as illustrated in Figure 1. The processor 91 can also include the functions of the MPU 203.

[0143] Thus, the arithmetic unit 2 operates as an information processing device that performs various processing methods by reading and executing a program. Furthermore, the arithmetic unit 2 can also achieve the same functions as the embodiment described above by reading the program from the recording medium using a media reader and executing the read program. Note that the program referred to here is not limited to being executed by the arithmetic unit 2. For example, the present invention can be similarly applied when another computer or server executes the program, or when they cooperate to execute the program.

[0144] This program can be distributed via networks such as the internet. Furthermore, this program can be recorded on computer-readable storage media such as hard disks, flexible disks (floppy disks), CD-ROMs, MOs (Magneto-Optical disks), and DVDs (Digital Versatile Discs), and executed by reading the program from these media using a computer.

[0145] Some examples of the combinations of technical features that will be disclosed are listed below.

[0146] (1) A concentration calculation device comprising: a prism on which a object to be measured is attached to a predetermined surface; a camera for photographing the predetermined surface; a first optical axis rotation unit that rotates light from a light-emitting unit located near the camera so as to cause total internal reflection of the light to be incident on the prism; a second optical axis rotation unit that causes the light emitted from the prism after total internal reflection to be incident on a light-receiving unit located near the camera; a housing for housing the light-emitting unit, the light-receiving unit, the first optical axis rotation unit, and the second optical axis rotation unit; and a confirmation window mounted in the housing at a position where the light-emitting unit and the light-receiving unit can be confirmed. (2) The concentration calculation device according to (1), further comprising a concentration calculation unit that applies a correction to the absorption spectrum measured based on the light collected by the light-receiving unit based on the image captured by the camera, and calculates the concentration of the object to be measured based on the corrected absorption spectrum. (3) The density calculation device according to (1), characterized in that the light-emitting unit has a first collimating lens that converts light emitted from the emission unit into parallel light, and the light-receiving unit has a second collimating lens that collects light emitted from the prism and inputs it to the incidence unit. (4) The density calculation device according to (3), characterized in that the first optical axis rotation unit is detachable from the housing, and the confirmation window has a first confirmation window arranged in the direction in which light emitted from the emission unit and passing through the first collimating lens travels in a straight line. (5) The density calculation device according to (3) or (4), characterized in that the first optical axis rotation unit is a half mirror, and the confirmation window has a first confirmation window arranged in the direction in which light emitted from the emission unit and passing through the first collimating lens travels in a straight line through the first optical axis rotation unit. (6) The density calculation device according to any one of (3) to (5), characterized in that the second optical axis rotating part is detachable from the housing, and the confirmation window has a second confirmation window arranged in the direction in which light emitted from the emission part, passing through the first collimating lens and rotated by the first optical axis rotating part travels in a straight line.(7) The density calculation device according to any one of (3) to (6), characterized in that the second optical axis rotation part is a half mirror, and the confirmation window has a second confirmation window arranged in a direction in which light emitted from the emission part, passing through the first collimating lens and rotated in the first optical axis rotation part passes through the second optical axis rotation part and travels in a straight line. (8) The density calculation device according to any one of (1) to (7), characterized in that the light emission part has a light source, the light receiving part has a spectrometer, and the device further comprises a cooling mechanism for cooling the inside of the housing. (9) The density calculation device according to any one of (1) to (8), characterized in that the rotation angle of the first optical axis rotation part is adjustable. (10) The density calculation device according to (9), characterized in that the prism is hemispherical with a spherical surface as the predetermined surface. (11) The density calculation device according to (10), further comprising a calculation part that calculates the average thickness of the object to be measured based on the light collected by the light receiving part obtained by changing the rotation angle of the first optical axis rotation part. (12) The concentration calculation device according to any one of (1) to (8), characterized in that the prism is hemispherical with the cut surface being the predetermined surface. (13) The concentration calculation device according to any one of (1) to (12), characterized in that the prism, the camera and the housing are located outside the environment in which the object to be measured exists, and the predetermined surface of the prism is exposed within the environment in which the object to be measured exists.

[0147] 1 ATR device 2 Calculation unit 10 Concentration calculation device 31 Incident element 32 Photodetector 100 Housing 101, 103 Collimating lenses 102, 104 XYZ stage 105 Prism 106, 107, 114 Mirror 111 Camera 112 Lens 113 Focus adjustment stage 121, 122 Collimation adjustment window 201, 204 White light source 202 Spectrometer 203 MPU 211, 212 ATR fiber 213 USB cable 214 Fiber 220 Cooling mechanism 300 Beam profiler 301 Power meter P Target substance

Claims

1. A density calculation device comprising: a prism on which a surface to be measured is attached; a camera for photographing the predetermined surface; a first optical axis rotation unit that rotates light from a light-emitting unit located near the camera so as to cause total internal reflection of light into the prism; a second optical axis rotation unit that causes the light emitted from the prism after total internal reflection to be incident into a light-receiving unit located near the camera; a housing that houses the light-emitting unit, the light-receiving unit, the first optical axis rotation unit, and the second optical axis rotation unit; and an inspection window mounted in the housing at a position where the light-emitting unit and the light-receiving unit can be seen.

2. The concentration calculation device according to claim 1, further comprising a concentration calculation unit that applies a correction to the absorption spectrum measured based on the light collected by the light receiving unit, based on the image captured by the camera, and calculates the concentration of the object to be measured based on the corrected absorption spectrum.

3. The density calculation device according to claim 1, characterized in that the light-emitting unit has a first collimating lens that converts light emitted from the emission unit into parallel light, and the light-receiving unit has a second collimating lens that focuses light emitted from the prism and inputs it to the incidence unit.

4. The density calculation apparatus according to claim 3, characterized in that the first optical axis rotation unit is detachable from the housing, and the confirmation window has a first confirmation window arranged in the direction in which light emitted from the emission unit and passing through the first collimating lens travels in a straight line.

5. The density calculation apparatus according to claim 3, characterized in that the first optical axis rotation part is a half mirror, and the confirmation window has a first confirmation window arranged in a direction in which light emitted from the emission part and passing through the first collimating lens passes through the first optical axis rotation part and travels in a straight line.

6. The density calculation apparatus according to claim 3, characterized in that the second optical axis rotating part is detachable from the housing, and the confirmation window has a second confirmation window arranged in the direction in which light emitted from the emission part, passing through the first collimating lens and rotated by the first optical axis rotating part travels in a straight line.

7. The density calculation device according to claim 3, characterized in that the second optical axis rotation section is a half mirror, and the confirmation window is a second confirmation window arranged in a direction in which light emitted from the emission section, passing through the first collimating lens and rotated in the first optical axis rotation section, passes through the second optical axis rotation section and travels in a straight line.

8. The concentration calculation apparatus according to claim 1, characterized in that the light-emitting unit has a light source, the light-receiving unit has a spectrometer, and the apparatus further comprises a cooling mechanism for cooling the inside of the housing.

9. The concentration calculation device according to claim 1, characterized in that the rotation angle of the first optical axis rotation unit is adjustable.

10. The density calculation device according to claim 9, characterized in that the prism is semi-spherical with a spherical surface as the predetermined surface.

11. The density calculation device according to claim 10, further comprising a calculation unit that calculates the average thickness of the object to be measured based on the light collected by the light receiving unit obtained by changing the rotation angle of the first optical axis rotating unit.

12. The concentration calculation device according to claim 1, characterized in that the prism is hemispherical with its cross-section being the predetermined surface.

13. The concentration calculation apparatus according to claim 1, characterized in that the prism, the camera, and the housing are located outside the environment in which the object to be measured exists, and the predetermined surface of the prism is exposed within the environment in which the object to be measured exists.

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