JP2017021024A - Liquid immersion probe, infrared spectrophotometer and atr crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid immersion probe that can make a sufficient use of an incident light beam for metrology, and can easily and surely measure the incident light with high accuracy.SOLUTION: A liquid immersion probe of the present invention is the liquid immersion probe that comprises: an almost column-shaped ATR crystal that has a light emission part and light emerging part on one bottom surface side; light guide means for making a light beam incident upon the ATR crystal from the light emission part; and light reception means that receives the light beam incident made by the light guide means and reflected upon a lateral surface of the ATR crystal and on another bottom surface side thereof, and emerging from the light emerging part, in which at least a peripheral part of the other bottom surface of the ATR crystal is a curve surface continuous from the lateral surface. It is preferable that the peripheral part of the other bottom surface of the ATR crystal is a spherical surface. It is preferable that a radius of curvature of the spherical surface is the almost same as a radius of the column. Another present invention is an infrared spectrophotometer that includes the liquid immersion probe composed of a configuration described in the above.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an immersion probe, an infrared spectrophotometer, and an ATR crystal.

  Conventionally, an immersion probe is used, for example, to measure the progress of a reaction in a chemical reaction tank. (1) As such an immersion probe, a light-emitting optical fiber as a light-emitting means and a light-receiving optical fiber that receives light from the light-emitting optical fiber are provided in the optical path from the light-emitting optical fiber to the light-receiving optical fiber. A cavity portion in which a reaction liquid to be measured can be interposed is provided (see JP 2009-250825 A). Then, when light is emitted from the light-emitting optical fiber in a state where the immersion probe is immersed in the reaction liquid, a part of the wavelength of light is absorbed when the light passes through the reaction liquid interposed in the cavity. Is done. For this reason, by analyzing the light received by the light receiving optical fiber, it is possible to grasp the state of the reaction solution and the like, and thus the progress of the reaction can be measured.

  One of the methods for analyzing a substance is an attenuated total reflection method (ATR method (attenuated total reflection method)). (2) In this total reflection attenuation method, as shown in FIG. 19, when the light beam 103 is incident on the surface of the measurement object 102 at an incident angle greater than the critical angle, the light beam 103 is reflected at the interface between the prism 101 and the measurement object 102. Total reflection. Then, the evanescent wave penetrates to the measurement object 102 side during total reflection. In total reflection, the light beam is absorbed (penetrated) unique to the measurement object 102. Therefore, by analyzing the light beam 103 emitted from the prism 101, the state of the measurement target can be grasped. An ATR probe is known as an element for measuring the state of a substance using this total reflection attenuation method (see Japanese Patent Application Laid-Open No. 2004-85433). Such an ATR probe includes an ATR crystal, a light guide optical fiber for making the light incident on the ATR crystal, and a light receiving optical fiber for receiving the light emitted from the ATR crystal. The ATR crystal reflects the light. It has a pyramid part or a cone part. Further, the ATR probe includes an incident lens that is disposed between the light guide optical fiber and the ATR crystal and adjusts the optical path so that parallel light is incident on the ATR crystal. The ATR probe is provided between the light receiving optical fiber and the ATR crystal, and includes an exit lens for adjusting the optical path so that parallel light is incident on the light receiving optical fiber. By the incident lens and the exit lens, the parallel light beam is totally reflected at the pyramid portion of the ATR crystal, and the totally reflected light beam is converted into the parallel light beam and received by the light receiving optical fiber, and the above-described measurement is performed. .

  Further, (3) a substantially cylindrical ATR crystal having an incident part and an emission part on one bottom surface side, a light guide means for making a light beam incident on the ATR crystal from the incident part, and incident by this light guide means And a light receiving means for receiving the light beam reflected from the side surface and the other bottom surface side of the ATR crystal and emitted from the emitting portion, wherein the incident portion and the emitting portion are not parallel to the virtual plane of the ATR crystal. An immersion probe composed of an inclined surface is known (Japanese Patent Laid-Open No. 2015-75448). In the immersion probe using the ATR crystal having a substantially cylindrical shape, the light incident from the light guide means is repeatedly reflected on the side surface of the ATR crystal while being immersed in the liquid to be measured. Proceeding toward the bottom surface on the other side in a substantially spiral shape, reflected on the bottom surface on the other side, and proceeding toward the bottom surface on one side in a substantially spiral shape by repeating reflection on the side surface of the ATR crystal again, such as Upon reflection, the light beam absorbs the wavelength inherent to the measurement object. The light beam that has traveled through the ATR crystal in this way is emitted from the emitting portion and received by the light receiving means. By analyzing the light received by the light receiving means and specifying the absorbed light, it is possible to determine the state of the measurement object.

JP 2009-250825 A JP 2004-85433 A Japanese Patent Laying-Open No. 2015-75448

  However, (1) In the conventional immersion probe having a cavity, accurate measurement cannot be performed unless the liquid to be measured flows into the cavity. Furthermore, if bubbles are present in the liquid interposed in the cavity, accurate measurement cannot be performed.

  (2) In the ATR probe, even if the optical lens for adjusting the optical path is provided as described above, the light is surely totally reflected by the ATR crystal and is accurately received by the light receiving optical fiber. Therefore, it is necessary to accurately position the light guide optical fiber, the light receiving optical fiber, the optical lens, and the ATR crystal. That is, even if a slight deviation occurs in the positioning, the light receiving optical fiber cannot accurately receive the light beam and accurate measurement cannot be performed. Furthermore, in the total reflection attenuation method, as described above, it is necessary to allow light to be incident on the interface with the measurement object at an incident angle greater than the critical angle, and the critical angle differs depending on the refractive index of the measurement object. It is necessary to perform the positioning as described above with accuracy each time.

  Further, (3) in an immersion probe using an ATR crystal having a substantially cylindrical shape as in Patent Document 3, since the light beam is reflected a plurality of times on the side surface of the substantially cylindrical shape, the above (1) and Although high-accuracy measurement can be performed easily and reliably as compared with (2), as a result of intensive studies by the inventor, it has been found that the incident light beam is not sufficiently utilized for measurement. The reason for this is that when the inventor has studied carefully, the corner between the side surface of the substantially cylindrical ATR crystal and the bottom surface on the other side is a discontinuous point. This is probably because the light beam is emitted to the liquid to be measured, and the emitted light quantity is not used for the measurement.

  Therefore, the present invention has been made paying attention to the disadvantages of the above-described conventional technology, and an immersion probe that can sufficiently use incident light for measurement and can perform more accurate measurement easily and reliably. And an infrared spectrophotometer and an ATR crystal.

  The present invention has been made to solve the above problems, and an immersion probe according to the present invention includes an ATR crystal having a substantially cylindrical shape having an incident portion and an emitting portion on one bottom surface side, and the incident portion. And a light receiving means for receiving the light beam incident on the side surface and the other bottom surface side of the ATR crystal and emitted from the emitting portion. An at least peripheral portion of the other bottom surface of the ATR crystal is a curved surface continuous from the side surface.

  When the light beam from the light guiding means is incident on the ATR crystal in a state where the immersion probe is immersed in the liquid to be measured, the light beam repeatedly reflects on the side surface of the ATR crystal, and is substantially cylindrical. Proceeds in the ATR crystal in a substantially spiral shape toward the other bottom surface. Then, this light beam is reflected on the bottom surface on the other side, and is again reflected on the side surface of the ATR crystal to advance toward the bottom surface on one side (the bottom surface on the incident portion and the emission portion side) in a spiral manner. During such reflection, the light beam absorbs the wavelength inherent to the measurement object. The light beam that has traveled through the ATR crystal in this way is emitted from the emitting portion and received by the light receiving means. By analyzing the light received by the light receiving means and specifying the absorbed light, it is possible to determine the state of the measurement object. In the immersion probe, as described above, the light beam travels in a substantially spiral shape in the substantially cylindrical ATR crystal, and the reflection of the light beam is repeatedly performed on the side surface of the ATR crystal. Therefore, highly accurate measurement can be performed easily and reliably.

  Moreover, since the immersion probe is a curved surface in which at least the peripheral portion of the other bottom surface of the ATR crystal is continuous from the side surface as described above, the light beam is emitted from the boundary portion between the side surface and the bottom surface to the liquid to be measured. Can be suppressed. For this reason, the said immersion probe can utilize the incident light beam efficiently for a measurement, and can perform a highly accurate measurement easily and reliably.

  The peripheral edge of the other bottom surface of the ATR crystal is preferably a spherical surface. Thereby, a light beam can be more reliably reflected toward the emitting portion side at the peripheral edge portion of the bottom surface. In the present invention, “spherical surface” does not mean the entire surface of a sphere, but means a surface constituting a part of the surface of the sphere.

  It is preferable that the radius of curvature of the spherical surface is substantially the same as the radius of the cylinder. Thereby, a light beam can be more reliably reflected toward the emitting portion side at the peripheral edge portion of the bottom surface.

  It is preferable that the incident part or the emitting part is composed of an inclined surface that is not parallel to a virtual plane perpendicular to the axial direction of the ATR crystal. As described above, the incident portion or the emission portion is configured by the inclined surface that is not parallel to the virtual plane of the ATR crystal, so that the light beam can be easily incident or emitted so as to proceed in a substantially spiral shape as described above. Furthermore, it is preferable that the angle α formed between the normal direction of the incident part or the outgoing part and the virtual plane perpendicular to the axial direction of the ATR crystal is less than 45 °, so that it proceeds in a substantially spiral shape as described above. In addition, it is possible to more easily and surely enter and exit the ATR crystal.

  In this case, it is preferable that the axial width W of the cylinder from the side surface in the axial projection region of the peripheral edge that is the spherical surface is L (1-cos 2α) or more (where L is the radius of the cylinder). .

  As a result, the light beam that has spirally traveled toward the other bottom surface can be accurately incident on the peripheral edge that is a spherical surface, and can be accurately reflected toward the bottom surface by this bottom surface.

  Another invention for solving the above problem is an infrared spectrophotometer including the immersion probe. Since the infrared spectrophotometer includes the immersion probe, highly accurate measurement can be performed easily and reliably.

  Furthermore, an ATR crystal according to another invention for solving the above-described problem has a substantially cylindrical shape having an incident portion and an emission portion on one bottom surface side, and at least a peripheral portion of the other bottom surface is continuous from the side surface. It is a curved surface.

  When the ATR crystal is immersed in the liquid to be measured and a light beam is incident from the incident portion, the light beam is repeatedly reflected on the side surface of the ATR crystal, and is substantially spiral in the substantially cylindrical ATR crystal. To the other bottom surface side, reflected at the peripheral edge of the bottom surface on the other side, and repeatedly reflected on the side surface of the ATR crystal again to form a substantially spiral bottom surface (on the incident side and emission side side). In such a reflection, the light beam absorbs a wavelength specific to the measurement object, and the state of the measurement object or the like can be determined by specifying the absorbed light beam. In the immersion probe, as described above, the light beam travels in a substantially spiral shape in the substantially cylindrical ATR crystal, and the reflection of the light beam is repeatedly performed on the side surface of the ATR crystal. Furthermore, since at least the peripheral part of the other bottom surface of the ATR crystal is a curved surface continuous from the side surface, it is possible to suppress the emission of light from the connecting portion between the side surface and the bottom surface to the liquid to be measured. Therefore, the incident light beam can be efficiently used for measurement, and more accurate measurement can be easily and reliably performed.

  Note that the curvature radius of the spherical surface is substantially the same as the radius of the cylinder is not limited to the case where both are completely the same. For example, the curvature radius of the spherical surface is 90% to 110% of the radius of the cylinder, preferably Also included is 95% or more and 105% or less. The virtual plane means a virtual plane perpendicular to the axis of the substantially cylindrical ATR crystal. Further, the inclined surface means a surface that is not parallel to the virtual plane, that is, a surface that is inclined with respect to the virtual plane, and is not limited to a flat surface but may be a curved surface.

  As described above, the immersion probe, the infrared spectrophotometer, and the ATR crystal of the present invention can sufficiently use the emitted light for measurement, and can perform more accurate measurement easily and reliably.

It is the schematic of the infrared spectrophotometer which concerns on one Embodiment of this invention. It is a typical side view including a partial cross section which shows the immersion probe of the infrared spectrophotometer of FIG. FIGS. 3A and 3B are schematic explanatory views showing a main part of the immersion probe of FIG. 2, wherein FIG. 3A is a schematic side view, FIG. 2B is a schematic plan view, and FIG. is there. FIG. 4 is a schematic side view showing a main part of an ATR crystal of the immersion probe in FIG. 3. FIG. 4 is a schematic explanatory view of an optical path of the ATR crystal of FIG. 3, (A) is a schematic side view for explaining an incident optical path, and (B) is a schematic side view for explaining an outgoing optical path. (C) is a schematic plan view for explaining the optical path. FIG. 6 is a schematic side view of an immersion probe according to another embodiment. It is a typical sectional view showing an important section of an immersion probe concerning other embodiments. FIG. 10 is a schematic side view showing a main part of an immersion probe according to another embodiment. FIG. 10 is a schematic side view showing a main part of an immersion probe according to another embodiment. FIG. 10 is a schematic side view showing a main part of an immersion probe according to another embodiment. It is a typical side view including a partial cross section which shows the principal part of the immersion probe which concerns on other embodiment. FIG. 10 is a schematic side view showing a main part of an immersion probe according to another embodiment. It is typical explanatory drawing which shows the principal part of the immersion probe which concerns on other embodiment, Comprising: (A) is a typical top view, (B) is a typical front view. It is typical explanatory drawing which shows the principal part of the immersion probe which concerns on other embodiment, Comprising: (A) is a typical top view, (B) is a typical front view. FIG. 10 is a schematic side view showing a main part of an immersion probe according to another embodiment. It is typical explanatory drawing which shows the principal part of the immersion probe which concerns on other embodiment, Comprising: (A) is a typical side view, (B) is a typical top view. 4 is a graph showing measurement results of water and ethanol absorbance distributions in Example 1. It is a graph which shows the measurement result of the light absorbency distribution of the copper sulfate from which the density | concentration in Example 2 differs. It is typical sectional drawing which shows the conventional optical probe.

<Infrared spectrophotometer>
An infrared spectrophotometer 1 in FIG. 1 is a Fourier transform infrared spectrophotometer, and is a device that obtains spectral information by applying infrared light to a measurement target to obtain characteristics, states, and the like of the measurement target. For example, the infrared spectrophotometer 1 can measure the reaction state of the organic solvent L.

  The infrared spectrophotometer 1 includes an immersion probe 2, a photometer main body 3, and a connection portion 4 that connects the immersion probe 2 and the photometer main body 3.

(Immersion probe)
The immersion probe 2 is an optical element that obtains reflected light by irradiating a measurement target with infrared light. By immersing the immersion probe 2 in the organic solvent L, it is possible to irradiate infrared light and obtain reflected light.

  As shown in FIGS. 2 to 5, the immersion probe 2 includes a holding unit 14 (holding unit) that holds the ATR crystal 7, the light guide unit 12, the light receiving unit 13, the reflection unit 11, the ATR crystal 7, and the like.

  The ATR crystal 7 has a substantially cylindrical shape, and has an incident portion 8 and an emission portion 9 on one bottom side. In the present embodiment, the side where the incident portion 8 and the emission portion 9 of the ATR crystal 7 are provided is referred to as the upper side, and the other bottom surface side is referred to as the lower side for the sake of convenience.

  The ATR crystal 7 is disposed at the lower end portion of the immersion probe 2, and the lower end of the ATR crystal 7 is disposed so as to protrude from below the holding portion 14 (see FIG. 2). The ATR crystal 7 is used with its lower protruding portion immersed in an organic solvent L (see FIG. 1). Then, the light beam emitted from the light guiding means 12 enters the ATR crystal 7 from the incident portion 8 and is reflected by the side surface of the ATR crystal 7 a plurality of times. Here, the light beam incident from the incident part 8 advances in a substantially spiral shape downward while reflecting the inside of the substantially cylindrical ATR crystal 7 on the side surface (see FIG. 5A), and The light is reflected at the peripheral edge portion 10a, and further progresses in a spiral shape upward while being reflected at the side surface (see FIG. 5B). At the time of this reflection, an evanescent wave penetrates to the organic solvent L side at the interface with the organic solvent L. That is, upon reflection, the light beam is absorbed (penetrated) unique to the organic solvent L. Then, the light beam reflected by the side surface a plurality of times as described above is emitted from the emission unit 9 and received by the light receiving means 13. By analyzing the light beam received by the light receiving means 13, the state of the measurement object can be grasped.

  The ATR crystal 7 is not particularly limited, but may be made of diamond, sapphire, zircon, quartz or the like. Among these, sapphire or zircon is preferable from the viewpoint of high refractive index, inert properties, workability, and the like.

  The lower limit of the refractive index of the ATR crystal 7 is preferably 1.43, and more preferably 1.45. If the refractive index is less than the lower limit, the difference in refractive index from the measurement target becomes too small, and the critical angle for total reflection may be too small. The upper limit of the refractive index is not particularly limited, and can be set to 2.5, for example. The refractive index is a value measured using a light beam having a wavelength of 589.3 nm (sodium D-line) at a temperature of 25 ° C. and a humidity of 50%. The average value of the refractive index and the refractive index of extraordinary rays.

  The incidence part 8 and the emission part 9 are composed of an inclined surface 7 a that is non-parallel to a virtual plane B perpendicular to the axial direction of the ATR crystal 7. The inclined surface 7a constituting the incident portion 8 or the emission portion 9 is formed by cutting an ATR crystal constituent material. Moreover, the inclined surface 7a which comprises the entrance part 8 and the output part 9 exists in the same plane (refer FIG.4 and FIG.5), and one side nearer than the center of this plane (on the paper surface of FIG.5 (C)) The incident portion 8 is disposed on the upper side, and the emitting portion 9 is disposed on the other outer side (lower side on the paper surface of FIG. 5C). Specifically, one bottom surface of the ATR crystal 7 is formed in a step shape as shown in FIGS. 3A and 4, and two parallel surfaces 7 b slightly inclined to the virtual plane B, It is comprised from the surface (the said inclined surface 7a) which comprises a step between the two surfaces 7b. And the surface (the inclined surface 7 a) constituting this step functions as the incident portion 8 and the emitting portion 9. As will be described later, the ATR crystal 7 is provided so that a light beam is incident on the incident portion 8 substantially perpendicularly (from the normal direction of the inclined surface 7a) to the incident portion 8, and from the emitting portion 9. A light beam is provided so as to be emitted substantially perpendicularly to the emitting portion 9 (in the normal direction of the inclined surface 7a). Here, “substantially perpendicular” means that the angle formed with the inclined surface 7a is 70 ° or more, preferably 80 ° or more.

  As described above, the inclined surface 7a constituting the incident portion 8 and the emission portion 9 is arranged not to face downward (to face upward). If the inclined surface 7a is disposed downward, there is a risk that it will be difficult for the light beam to enter the ATR crystal 7 so as to proceed in a spiral manner downward as described above. The upper limit of the angle α (see FIG. 4) formed by the normal direction of the inclined surface 7a and the virtual plane B of the ATR crystal 7 is preferably 45 °, more preferably 35 °, and even more preferably 20 °. If the angle α formed between the normal direction of the inclined surface 7a of the incident portion 8 and the virtual plane B exceeds the above upper limit, it is difficult to cause the light to enter the ATR crystal 7 so as to proceed in a spiral manner as described above. There is. In addition, when the angle α formed by the inclined surface 7a of the emitting portion 9 and the virtual plane B exceeds the upper limit, it may be difficult to emit the light beam that has progressed in a substantially spiral shape as described above. The lower limit of the angle α formed by the normal direction of the inclined surface 7a and the virtual plane B is preferably 5 °, and more preferably 10 °.

  The upper edge (the upper edge of the right side surface in FIG. 4) of the side surface of the ATR crystal 7 facing the incident portion 8 is disposed below the incident portion 8. Similarly, the upper edge of the side surface of the ATR crystal 7 facing the emission part 9 is disposed below the emission part 9. Specifically, the lower edge of the inclined surface 7a constituting the incident portion 8 and the emission portion 9 and the upper edge on the side surface are disposed at substantially the same position in the axial direction (see FIG. 4). As described above, the upper edge of the side surface is disposed below the incident part 8 and the emission part 9, so that the light beam incident from the incident part 8 does not travel downward but is reflected at the horizontal position. Therefore, there is little possibility that a light beam emitted from the emission part 9 is generated. In other words, the light beam emitted from the emission unit 9 only by being reflected at the horizontal position becomes measurement noise and may cause a decrease in measurement accuracy. However, by configuring as described above, the light beam incident from the incident unit 8 is Since the light is reflected downward on the side surface, it is possible to prevent the light from being emitted from the light emitting part 9 by reflecting only at the horizontal position, and thereby, highly accurate measurement can be performed easily and reliably.

  As described above, the projection position of the incident portion 8 in the axial direction is disposed outside the axis O (see FIG. 5C). The axial projection position of the incident portion 8 is preferably outside 80% or more of the radius of the virtual plane B. That is, the lower limit of the distance between the incident portion 8 and the axis O at the axial projection position is preferably 80%, more preferably 85%, and even more preferably 89% of the radius of the virtual plane B as described above. As a result, the light incident from the incident portion 8 tends to have an acute angle with respect to the side surface, and the incident angle becomes greater than or equal to the critical angle in various measurement objects, so that the light can be totally reflected within the ATR crystal 7 easily and reliably. .

  Similarly, the projection position in the axial direction of the emitting portion 9 is disposed outside the axis O as described above (see FIG. 5C). The lower limit of the distance between the axial projection position of the emitting portion 9 and the axis O is preferably 80% of the radius of the virtual plane B, more preferably 85%, and even more preferably 89%. As a result, the light beam totally reflected in the ATR crystal 7 as described above can be accurately emitted from the emission portion 9.

  On the other hand, the upper limit of the distance between the incident portion 8 and / or the emission portion 9 at the axial projection position and the axis O is preferably 95% of the radius of the virtual plane B, more preferably 93%, and still more preferably 91%. Thereby, it is easy to make a light ray enter from the incident part 8 exactly, and to make it easy to emit a light ray from the output part 9 correctly. Note that the distance between the axial projection position of the emitting portion 9 and the axis O and the distance between the axial projection position of the incident portion 8 and the axis O are substantially the same.

  The diameter of the ATR crystal 7 (the diameter of the virtual plane B) is not particularly limited, but the lower limit of this diameter is preferably 0.4 cm, and more preferably 1 cm. Further, the upper limit of this diameter is preferably 5 cm, and more preferably 3 cm. When the diameter is less than the lower limit, the ATR crystal 7 becomes too small and it may be difficult to handle. On the other hand, if the diameter exceeds the upper limit, the ATR crystal 7 may be expensive.

  The vertical length of the side surface of the ATR crystal 7 (the axial length from the incident portion 8 to the lower end of the side surface) is not particularly limited, but the lower limit of the vertical length is preferably 0.5 cm and more preferably 2 cm. Further, the upper limit of the vertical length is preferably 20 cm, and more preferably 10 cm. When the upper and lower lengths are less than the lower limit, the ATR crystal 7 becomes too small, and there is a possibility that the handling becomes difficult. On the other hand, when the vertical length exceeds the upper limit, the ATR crystal 7 may be expensive. The lower limit of the ratio of the vertical length to the diameter of the ATR crystal 7 is preferably 1 time, and more preferably 2 times. The upper limit of the ratio is preferably 10 times, more preferably 8 times.

  The peripheral portion 10a of the bottom surface 10 on the lower side of the ATR crystal 7 (the bottom surface on which the incident portion 8 and the emitting portion 9 are not formed) is a curved surface continuous from the side surface. The light beam that has reached the bottom surface 10 on the lower side of the ATR crystal 7 is reflected by the peripheral edge portion 10a of the bottom surface 10 and travels upward. Since the peripheral edge portion 10a is a curved surface continuous from the side surface, it is possible to suppress the emission of light from the boundary portion between the side surface and the bottom surface 10 to the liquid to be measured. The central portion of the lower bottom surface 10 is a surface parallel to the virtual plane B, and the inside of the peripheral edge portion 10a is not hollow. That is, the material for forming the ATR crystal 7 exists inside the peripheral edge portion 10a.

  The curved surface of the peripheral edge portion 10a of the bottom surface 10 on the lower side of the ATR crystal is a spherical surface. The radius of curvature of this spherical surface is substantially the same as the radius of the cylinder of the ATR crystal 7.

  The width W in the axial direction (axial center O side) of the cylinder from the side surface in the axial projection area of the peripheral edge 10a that is a spherical surface is L (1-cos 2α) or more (L is the radius of the cylinder). . Furthermore, the lower limit of the width W is preferably 1.1 times L (1-cos2α), more preferably 1.2 times. Thereby, the light reaching the bottom surface 10 on the lower side of the ATR crystal 7 is difficult to be incident on other than the peripheral edge portion 10a which is the spherical surface, and can more accurately reflect the light beam at the peripheral edge portion 10a.

  In addition, it is preferable that the said incident part 8 and the output part 9 are located in the axial direction projection area | region of the peripheral part 10a which is a spherical surface. That is, it is preferable that the peripheral edge portion 10 a of the bottom surface 10 exists below the incident portion 8 and the emission portion 9. Thereby, the light reaching the bottom surface 10 on the lower side of the ATR crystal 7 is more reliably incident on the peripheral edge portion 10a.

  The ATR crystal 7 is not particularly limited, but preferably has a metal film deposited on the peripheral portion 10a of the bottom surface 10 or at least a part of the outer surface of the side surface. Thereby, absorption of a specific light beam at the peripheral edge portion 10a or the side surface of the bottom surface 10 of the ATR crystal 7 is more likely to occur, and more accurate measurement can be performed. The metal film can be provided on the entire outer surface of the ATR crystal 7 or can be provided only on a portion immersed in the organic solvent L. Although it does not specifically limit as a metal used for this metal film, Silver, gold | metal | money, copper, zinc, aluminum, potassium etc. are mentioned. Further, the thickness of the metal film is not particularly limited, but is preferably 30 nm to 70 nm, and preferably 40 nm to 60 nm. When the thickness of the metal film is out of the above range, the effect of improving the measurement accuracy by the metal film may not be sufficiently obtained.

  The immersion probe 2 has, as the reflecting means 11, an incident position reflecting means for reflecting the light beam from the light guiding means 12 toward the incident portion 8, and a light beam emitted from the emitting portion 9 toward the light receiving means 13. The output position reflecting means is reflected. In the present embodiment, the incident position reflecting means and the emitting position reflecting means are composed of the same mirror 11. Specifically, as shown in FIG. 3A, the upper surface serving as a reflecting surface is inclined with respect to the virtual plane B so as to face the incident portion 8 and the emitting portion 9, and is placed and fixed on the ATR crystal 7. The mirror 11 is composed of a triangular prism. In addition, as said reflective surface, it can comprise from metal vapor deposition surfaces, such as aluminum, for example.

  The light guide means 12 emits a light beam from the incident portion 8 to the ATR crystal 7 by emitting the light beam to the reflecting surface of the mirror 11 as the incident position reflecting means, and an optical fiber as a waveguide. It has. In addition, as a waveguide, it is also possible to employ | adopt the hollow waveguide comprised from the metal pipe | tube which has a circular or square cross section, for example.

  The optical fiber of the light guiding means 12 is disposed substantially parallel to the axial direction of the ATR crystal 7. The diameter of the core of the optical fiber is not particularly limited, but the lower limit of the diameter is preferably 40 μm, and more preferably 50 μm. Further, the upper limit of the diameter is preferably 600 μm, and more preferably 500 μm. When the diameter of the core of the optical fiber is less than the lower limit, it may not be easy to make the light beam incident on the ATR crystal 7. On the other hand, when the diameter exceeds the upper limit, the immersion probe 2 becomes too large, and the handleability of the immersion probe 2 may be impaired.

  The light guide means 12 and the mirror 11 are provided so that the light beam is incident substantially perpendicular to the incident portion 8. That is, in the immersion probe 2, the light beam enters from the incident portion 8 toward the other bottom surface side (downward) in the axial direction. Here, the upper limit of the angle of the incident light beam (pre-incident light beam) with respect to the virtual plane B is preferably 45 °, more preferably 35 °, and even more preferably 20 °. If the angle of the light beam exceeds the upper limit, the number of times the light beam is reflected in the ATR crystal 7 may be too small. In addition, as a minimum of the said angle, 5 degrees is preferable and 10 degrees is more preferable. If the angle is less than the lower limit, it may be difficult to control the light beam.

  The light receiving means 13 receives a light beam emitted from the emission section 9 via a reflecting surface of the mirror 11 as the emission position means, and includes an optical fiber as a waveguide (FIG. 3). (See (C)). A hollow waveguide can also be adopted as the waveguide.

  The optical fiber of the light receiving means 13 is disposed substantially parallel to the axial direction of the ATR crystal 7. The diameter of the core of the optical fiber is not particularly limited, but the lower limit of the diameter is preferably 40 μm, and more preferably 50 μm. Further, the upper limit of the diameter is preferably 600 μm, and more preferably 500 μm. When the diameter of the core of the optical fiber is less than the lower limit, the light from the ATR crystal 7 may not be accurately received. On the other hand, when the diameter exceeds the upper limit, the immersion probe 2 becomes too large, and the handleability of the immersion probe 2 may be impaired. The emission position reflecting means 11 is provided so as to reflect the light beam emitted substantially perpendicularly from the emitting portion 9 toward the light receiving means 13 substantially parallel to the axial direction.

  The holding portion 14 has a cylindrical holding portion that holds the side surface of the ATR crystal 7 in an airtight manner. Specifically, the holding unit 14 has an O-ring 14a that is in close contact with the side surface of the ATR crystal 7, and the ATR crystal 7 is held in an air-tight manner by the O-ring 14a, and the organic solvent L and the like are guided. Adhering to the means 12 and the light receiving means 13 is accurately prevented.

(Photometer body)
The photometer body 3 includes a light source 21 that emits measurement light, an interferometer 22 that generates interference light, a detector 23 that detects interference light, and a conversion processing unit that obtains spectral information by Fourier transforming the detection signal of the detector. 24 and a display unit 25.

  The light source 21 emits infrared rays. Although it does not specifically limit as infrared light to radiate | emit, For example, the infrared light which has a wavelength component of 1 micrometer or more and 11 micrometers can be employ | adopted. The light source 21 is not particularly limited, but a tungsten iodine lamp or a high-intensity ceramic light source can be used.

  The interferometer 22 causes the light emitted from the light source 21 to interfere. The interferometer 22 is not particularly limited, and a Michelson interferometer, a Fizeau interferometer, a Mach-Zehnder interferometer, or the like can be used.

The detector 23 detects the light beam received from the immersion probe 2. The detector 23 is not particularly limited, and a DLATGS (Deuterated L-Aline Triglycine Sulphate) detector, an MCT (Mercury Cadmium Tellurium) detector, a LiTaO ₃ (Lithium Tantalite) detector, or the like can be used.

  The conversion processing unit 24 digitizes the infrared light detected by the detector 23 and creates spectral information by Fourier-transforming the digitized data. The conversion processing unit 24 is specifically a central processing unit or a storage device.

  The display unit 25 displays the spectrum information obtained by the conversion processing unit 24. As the display unit 25, a display, a printer, or the like can be used.

(Connection part)
The connection unit 4 optically connects the immersion probe 2 and the photometer body 3. The connection unit 4 includes a light guiding optical fiber for causing the light beam from the interferometer 22 to enter the immersion probe 2 and a light receiving optical fiber for causing the detector 23 to receive the light beam from the immersion probe 2. The light guide fiber and the light receiving optical fiber can be the same as the light guide means 12 and the light receiving means 13.

<Advantages>
In the infrared spectrophotometer 1, the light beam from the light guide unit 12 enters the ATR crystal 7 in a state where the lower end of the ATR crystal 7 of the immersion probe 2 is immersed in the organic solvent L, and is received by the light receiving unit 13. The reaction state of the organic solvent L can be grasped by analyzing the emitted light and identifying the absorbed light. Here, the light beam travels in a substantially spiral shape within the ATR crystal 7, and the reflection of the light beam is repeated at the peripheral portion 10 a of the side surface and the bottom surface 10 of the ATR crystal 7. Therefore, highly accurate measurement can be performed easily and reliably.

  As described above, the infrared spectrophotometer 1 determines the state of the object to be measured by absorbing the wavelength at the interface of the ATR crystal 7 with the organic solvent L, and thus has the conventional cavity. Compared to an immersion probe, there is less risk of measurement errors due to the presence of bubbles and the like, and highly accurate measurement can be performed easily and reliably.

  In addition, since the reflection of the light beam is performed on the side surface of the substantially cylindrical ATR crystal 7, the light beam incident from the light guide means 12 is likely to be totally reflected on the side surface of the substantially cylindrical ATR crystal 7. Compared to the one using the ATR crystal having the pyramid portion, the positioning of the light guiding means, the light receiving means and the ATR crystal is less required to be highly accurate, and high-precision measurement can be performed easily and reliably. Further, since the total reflection is likely to occur on the side surface of the ATR crystal 7 as described above, the liquid immersion probe 2 can be easily and reliably used for various inspection objects.

  Moreover, since the incident part 8 and the emission part 9 are provided on the same bottom surface side (upper bottom surface side) of the two bottom surfaces of the ATR crystal 7, the incident part 8 and the emission part 9 enter the ATR crystal 7 downward. The light beam that has traveled in a substantially spiral shape is reflected upward by the peripheral edge portion 10a of the lower bottom surface 10 and travels in the ATR crystal 7 upwardly in a spiral shape, and then exits from the exit portion 9. For this reason, the number of reflections of light rays is large, and more accurate measurement can be performed. In addition, since the incident portion 8 and the emission portion 9 are both disposed upward in this manner, the light guide means 12 and the light receiving means 13 can be disposed on the same side, for example, the emission portion 9 and the incidence portion 8. It is possible to immerse the organic solvent L in a lower portion where no is provided in the organic solvent L easily and reliably.

  In particular, since the light beam that has reached the bottom surface 10 below the ATR crystal 7 is accurately reflected at the peripheral edge portion 10a that is a curved surface continuous from the side surface, the light beam is a measurement target from the boundary portion between the side surface and the bottom surface 10. Therefore, the immersion probe can efficiently use the incident light beam for measurement, and can perform measurement with higher accuracy easily and reliably.

  Further, since the peripheral edge portion 10a is a spherical surface having a curvature radius substantially the same as the radius of the ATR crystal 7, the light beam reaching the peripheral edge portion 10a is reflected in a direction parallel to the virtual plane B (see FIG. 5A). ), The reflected light beam is further incident on another portion of the peripheral portion 10a, and the light beam incident on the other portion of the peripheral portion 10a is accurately reflected upward (see FIG. 5B). ).

  Since the inclined surface 7a constituting the incident portion 8 and the emitting portion 9 is in the same plane, and this inclined surface 7a is formed by cutting the ATR crystal constituent material, the incident portion 8 and the emitting portion can be easily and reliably obtained. The part 9 can be formed, and the manufacturing cost of the immersion probe 2 can be reduced.

  Moreover, since the incident part 8 is comprised from the inclined surface 7a non-parallel with respect to the virtual plane B of the ATR crystal | crystallization 7, as mentioned above, it is easy to inject a light beam so that it may advance substantially helically. Furthermore, since the emitting portion 9 is composed of the inclined surface 7a that is not parallel to the virtual plane B of the ATR crystal 7, it is easy to emit the light beam that has progressed in a substantially spiral shape as described above.

  Furthermore, since the waveguides of the light guide unit 12 and the light receiving unit 13 are disposed substantially parallel to the axial direction of the ATR crystal 7, the size of the apparatus can be easily and reliably reduced. In addition, since the light beam emitted from the waveguide of the light guide unit 12 is reflected by the reflecting unit 11 toward the incident portion 8, the light beam from the waveguide of the light guide unit 12 arranged as described above is reflected. It is possible to easily and surely enter the ATR crystal 7 from the incident portion 8. Further, since the light beam emitted from the light emitting section 9 is reflected by the reflecting means 11 toward the waveguide of the light receiving means 13, it is emitted from the light emitting section 9 by the waveguide of the light receiving means 13 arranged as described above. Can be received easily and reliably. In addition, since the reflecting means 11 at the incident position and the emitting position are composed of mirrors having the same configuration, the manufacturing cost of the immersion probe 2 can be reduced.

<Other embodiments>
The immersion probe, infrared spectrophotometer, and ATR crystal of the present invention are not limited to the above-described embodiment, and can be implemented in variously modified and improved modes.

  That is, in the above-described embodiment, the description has been given of the case where only the peripheral edge portion of the bottom surface (lower bottom surface) opposite to the entrance portion and the exit portion is provided on the curved surface, but the present invention is not limited to this. As shown in FIG. 4, a semispherical bottom surface 10 on the opposite side of the incident portion 8 and the emission portion 9 can also be used. In addition, about the structure similar to 1st embodiment in FIG. 6, the same code | symbol is used and the detailed description is abbreviate | omitted. Also, in FIGS. 7 to 16 to be described later, the same reference numerals are used for the same configurations as in the first embodiment, and the detailed description thereof is omitted.

  Moreover, in the said embodiment, although the axial direction width W of the cylinder from the side surface in the axial direction projection area | region of the peripheral part 10a was demonstrated more than L (1-cos2 (alpha)), this width W is on the bottom face of the lower side. There is no particular limitation as long as the reached light beam is accurately incident on the peripheral edge. In addition, when the angle β formed between the incident light ray and the virtual plane in the incident portion is not the same as the angle α, the width W can be set to L (1−cos 2β) or more, and L (1−cos 2β). ) Is preferably 1.1 times or more, more preferably 1.2 times or more.

  Furthermore, in the said embodiment, although the inside of the peripheral part 10a was demonstrated about what is not hollow, this invention is not limited to this, For example, as shown in FIG. 8 as long as an optical path is ensured. The inside of the peripheral edge portion 10a is hollow 10b (for example, a portion into which a liquid as a measurement object flows) is also within the range intended by the present invention.

  Further, the central portion of the peripheral portion 10a of the bottom surface 10 of the ATR crystal 7 has a circular arc shape 10c continuous from the peripheral portion 10a as shown in FIG. 8, or a conical shape 10d as shown in FIG. It is also possible to adopt what is. As shown in FIGS. 6 and 8, it is preferable that the bottom surface 10 has no discontinuity, and this has the advantage that noise light (light unnecessary for measurement) is difficult to be emitted from the emission portion. Referring to FIG. 8, the peripheral edge 10a of the bottom surface 10 has the same width (L (1-cos2α)) as that of the above embodiment, the central portion is continuous from the peripheral edge 10a and the curvature of the peripheral edge 10a. It is comprised from the spherical surface larger than a radius. In addition, by making the bottom surface 10 hemispherical as shown in FIG. 6, a light beam having an angle unsuitable for measurement is incident on the central portion of the bottom surface 10 among the light beams incident on the ATR crystal 7. When reflected, it can be suppressed to have the same angle as the light beam having an angle suitable for measurement, and therefore generation of noise light emitted from the emitting portion can be suppressed.

  Moreover, although what provided the reflection means comprised from the above mirrors was demonstrated, this invention is not limited to this. Specifically, as shown in FIG. 10, those having no reflecting means between the light guide means 22 and the incident portion 8 are also within the intended range of the present invention, and similarly, the emitting portion and the light receiving means. Those having no reflecting means (not shown) are also within the intended scope of the present invention. In FIG. 10, the light exit surface 22 a of the waveguide (optical fiber) of the light guide means 22 is disposed so as to face the incident portion 8, and the waveguide of the light guide means 22 is the axis of the ATR crystal 7. It is arranged non-parallel to the direction. Similarly, it is also possible to arrange the light receiving surface of the waveguide of the light receiving means so as to face the emitting portion, and arrange the waveguide of the light receiving means non-parallel to the axial direction.

  Furthermore, the immersion probe includes an incident position condensing unit that condenses the light emitted from the light guiding unit toward the incident part, thereby efficiently incident the light emitted from the light guiding unit on the ATR crystal. can do. That is, for example, as shown in FIG. 10, it is possible to provide the incident position condensing means 30 between the light guide means 22 and the incident portion 8. In the immersion probe shown in FIG. 10, the incident position condensing means 30 is attached to the light exit surface 22 a of the waveguide (optical fiber) of the light guiding means 22. The incident position condensing means 30 is not particularly limited as long as it is a condensing lens that can be suitably condensed on the incident portion 8 such as a cylindrical lens, but a radial type gradient index lens (Selfoc Lens (registered trademark)). Is preferably used. In addition, in the immersion probe including the substantially cylindrical ATR crystal as described above, since the measurement can be performed with high accuracy without using a strict parallel light beam, the radial type gradient index lens is used. However, it is not necessarily required to be provided strictly to the extent that a strict parallel light beam is obtained, and may be provided to the extent that light diffusion is suppressed.

  Similarly, the immersion probe further includes an output position condensing unit that condenses the light emitted from the emitting unit toward the light receiving unit, thereby efficiently receiving the light emitted from the emitting unit. Can be incident. Although the incident position condensing means 30 is shown in FIG. 10, the output position condensing means has the same configuration and is not shown.

  Further, the immersion probe can be provided with the light collecting means and the reflecting means. In order to provide the light collecting means and the reflecting means in this way, a method of providing a member as the light collecting means and a member as the reflecting means, respectively, and a member (light collecting and reflecting means) having a light collecting function and a reflective function It is conceivable to provide a method. As the former, for example, in an immersion probe having a reflecting means such as a mirror as in the above embodiment, a radial type gradient index lens (Selfoc lens (registered trademark) as shown in FIG. It is conceivable to add light collecting means such as)). As the latter, for example, as shown in FIG. 11 or FIG.

  As shown in FIG. 11 or FIG. 12, the light beam emitted from the light guide means 12 by the light collecting / reflecting means 31 is reflected toward the incident portion 8 and condensed to thereby guide the waveguide of the light guide means 12. Can be efficiently incident on the ATR crystal 7 even if the light is emitted from the light guide 12. In the immersion probe shown in FIG. 11, a concave mirror is used as the condensing / reflecting means 31, and the concave reflecting surface 31a of the concave mirror faces the exit surface of the light guiding means 12 and the incident portion 8 of the ATR crystal 7. It is arranged to do. In the immersion probe shown in FIG. 12, a hemispherical lens is used as the condensing and reflecting means 31, and the bottom surface functions as a reflecting surface by depositing aluminum or the like on the bottom surface of the hemispherical lens. 11 and 12, the condensing / reflecting means 31 at the incident position is illustrated, but the same configuration can be adopted for the condensing / reflecting means at the emitting position, and thus the condensing / reflecting means is arranged at the emitting position. Thus, even if the waveguide of the light receiving means is disposed substantially parallel to the axial direction of the ATR crystal, the light emitted from the emission part of the ATR crystal is reflected toward the light receiving means by the condensing reflection means. In addition, since the light is condensed, the light can be efficiently received by the light receiving means.

  Further, the immersion probe may be provided with a light shielding means for shielding unnecessary light (a part of the light emitted from the light guiding means) emitted from the light guiding means between the light guiding means and the incident portion. Is possible. Thereby, it is possible to prevent unnecessary rays from propagating through the ATR crystal. The light shielding means is not particularly limited. For example, a spacer having a hole having the same diameter as the light exit surface of the light guiding means can be used, and unnecessary light can be shielded by the spacer.

  Further, the incident portion 8 and the emission portion 9 are not limited to the same inclined surface 7a as in the above embodiment, but the inclined surface 37a and the emission portion of the incident portion 38 as shown in FIG. It is within the scope of the present invention to employ the ATR crystal 7 formed with 39 inclined surfaces 37b.

  Further, even when the incident portion and the emission portion are configured from the same inclined surface, the inclined surface 7a is not limited to a flat surface as in the above embodiment, and as illustrated in FIG. In addition, it is within the scope of the present invention that the inclined surface 47a is formed of a curved surface.

  Further, the bottom surface of the ATR crystal on which the incident portion or the emission portion is formed is not limited to the stepped shape as in the above embodiment, and the bottom surface is inclined 57a as shown in FIG. What is comprised only from this is also in the range which this invention intends.

  Further, as in the above-described embodiment, the inclined surface 7a is limited to the one provided substantially at the center in the radial direction of the ATR crystal 7 (the center in the left-right direction in FIGS. 3A and 3B and FIG. 4). Instead, as shown in FIG. 16, it is also within the intended range of the present invention that the inclined surface 67a is arranged to be biased toward one side in the radial direction (left side in FIG. 16).

  Furthermore, the immersion probe is not limited to those used by being immersed in an organic solvent, and can be immersed in various liquids. In addition, in the infrared spectrophotometer, the Fourier transform infrared spectrophotometer is also used. It is not limited, A dispersive infrared spectrophotometer may be sufficient. In addition, either a sweep type spectrometer or an array type spectrometer can be used.

  EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, and can be appropriately changed within the intended scope of the present invention.

[Example 1]
(ATR crystal)
The ATR crystal shown in FIG. 6 was immersed in the measurement target liquid, a light beam was incident from the incident portion, and the light beam from the emission portion was analyzed. The ATR probe used was made of Saffia, and had a substantially cylindrical shape with a diameter of 2 cm and a vertical length (axial length from the incident portion to the lower end of the side surface) of 5 cm. The normal direction of the incident part and the outgoing part is inclined by 15 ° with respect to the virtual bottom surface of the ATR crystal.

(Injection method)
As a light source incident on the incident portion, a 100 W tungsten lamp (“1682A” manufactured by SPEX, USA) was used. In addition, “270M” manufactured by SPEX of the United States was used as an interferometer. The light beam emitted from the spectroscope was incident on the incident portion from the normal direction of the incident portion via an optical fiber.

(Measuring method)
A light beam incident from the incident portion and reflected from the ATR crystal a plurality of times and then emitted from the emitting portion was received by a light receiver (“G6122” manufactured by Hamamatsu Photonics Co., Ltd.) via an optical fiber.

(Measurement result)
FIG. 17 shows the absorbance distribution when ethanol is used as the measurement target liquid and when water is used. In FIG. 17, the horizontal axis represents the wave number [1 / cm], and the vertical axis represents the absorbance. As apparent from FIG. 17, the absorbance distribution obtained by the ATR crystal represents the characteristics of water and ethanol, and the ATR crystal is used to perform high-precision measurement even with a 100 W tungsten lamp. I can see that

[Example 2]
In Example 2, measurement was performed in the same manner as in Example 1 except that four types of copper sulfate solutions having different concentrations were used, and “EPP-2000” manufactured by Ste11arNet was used as a spectroscope. In addition, the density | concentration of the four types of sulfuric acid solutions as a measuring object was 0 wt%, 10 wt%, 30 wt%, and 50 wt%, respectively.

  The absorbance distribution of the measurement results of Example 2 is shown in FIG. In FIG. 18, the horizontal axis represents the wavelength, and the vertical axis represents the light absorbance. As is apparent from FIG. 18, the distribution of light absorbance obtained by the ATR crystal corresponds to each copper concentration. By using the ATR crystal, high-accuracy measurement can be performed even with a 100 W tungsten lamp. It can be seen that can be done.

  As described above, the immersion probe of the present invention and the infrared spectrophotometer provided with the immersion probe can be used, for example, for measuring the reaction state of an organic solvent.

DESCRIPTION OF SYMBOLS 1 Infrared spectrophotometer 2 Immersion probe 3 Photometer main body 4 Connection part 7 ATR crystal | crystallization 7a, 37a, 37b, 47a, 57a Inclined surface 7b Plane 8, 38 Incident part 9, 39 Output part 10 The other bottom face 10a Peripheral part DESCRIPTION OF SYMBOLS 11 Reflecting means 12 Light emitting means 13 Light receiving means 14 Holding part 14a O-ring 21 Light source 22 Interferometer 23 Detector 24 Conversion processing part 25 Display part 30 Condensing means 31 Condensing reflecting means L Organic solvent B Virtual plane O Axis center

Claims (6)

A substantially cylindrical ATR crystal having an incident part and an emission part on one bottom side;
A light guiding means for causing a light beam to enter the ATR crystal from the incident portion;
An immersion probe that includes a light receiving means that receives light that is incident by the light guiding means, is reflected on the side surface and the other bottom surface side of the ATR crystal, and is emitted from the emitting portion,
An immersion probe, wherein at least a peripheral edge portion of the other bottom surface of the ATR crystal is a curved surface continuous from a side surface.   The immersion probe according to claim 1, wherein a peripheral portion of the other bottom surface of the ATR crystal is a spherical surface.   The immersion probe according to claim 2, wherein a radius of curvature of the spherical surface is substantially the same as a radius of the cylinder. The incident part or the emitting part is composed of an inclined surface that is not parallel to a virtual plane perpendicular to the axial direction of the ATR crystal, and an angle α formed between the normal direction of the incident part or the emitting part and the virtual plane is Less than 45 °,
The width W in the axial direction of the cylinder from the side surface in the axial projection region of the peripheral part which is the spherical surface is L (1-cos2α) or more, where L is the radius of the cylinder. The immersion probe as described.   An infrared spectrophotometer comprising the immersion probe according to any one of claims 1 to 4. It has a substantially cylindrical shape having an incident part and an emission part on one bottom side,
An ATR crystal in which at least the peripheral edge of the other bottom surface is a curved surface continuous from the side surface.

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