JP2005221257A - Measuring device, probe for measuring device, and measuring method of solute concentration and/or flow rate of liquid in passage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring device and a probe for the measuring device capable of improving operability by enabling a measuring position to be easily changed, and a measuring method of the solute concentration and/or the flow rate of liquid in a passage. <P>SOLUTION: This measuring device 1 is equipped with a light source module 100, and a probe 50 dipped in a sample solution in the passage 20, for condensing and irradiating excitation light and probe light to the sample solution. The probe 50 is equipped with an optical fiber 103 for guiding the excitation light and the probe light, a condensing lens 40 for condensing the guided excitation light and probe light, and a mirror 41 arranged in parallel so as to be faced to the bottom surface of the condensing lens 40. The excitation light condensed and irradiated to the sample solution forms a thermal lens in the sample solution, and the probe light transmitted through the thermal lens is reflected by the mirror 41, and a detector 54 detects the reflected probe light. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a measuring device, a probe for the measuring device, and a method for measuring the solute concentration or / and flow velocity of the liquid in the flow channel, and in particular, measures the solute concentration or / and flow velocity of the liquid in the flow channel using a thermal lens. The present invention relates to a measuring device, a probe for the measuring device, and a method for measuring a solute concentration or / and a flow velocity of a liquid in a flow path.

  As shown in FIG. 13, a conventional measuring apparatus 800 (for example, refer to Patent Document 1) that measures the solute concentration or / and flow velocity of the liquid in the flow path using a thermal lens is used. The sample solution in the flow path 811 formed inside is irradiated with an irradiation unit 801 that combines and irradiates excitation light and probe light with a multiplexer 815 and the plate member 810 with flow path. It comprises a light receiving unit 802 that receives excitation light and probe light. The position of the light receiving unit 802 is set so that the probe light from the irradiation unit 801 can be reliably received. The irradiation unit 801 is provided with a probe 850 including a rod lens 817 and an optical fiber 816 connected to the rod lens 817, and the light receiving unit 802 is a pinhole placed on the opposite side of the probe 850. A photoelectric converter 821 including an attached photodiode (Photo Diode) is provided.

  The plate member 810 with a rating is composed of three substrates bonded in three layers in order, and the flow path 811 formed inside is used for mixing, stirring, synthesizing, separating, extracting, detecting, etc. the sample solution. .

  The measuring apparatus 800 irradiates the excitation light from the excitation light source 812 to the flow path 811 of the plate member 810 with flow path, positions the focal point of the excitation light in the flow path 811, and forms a thermal lens there. Then, the probe light from the probe light source 813 that has passed through the thermal lens is selectively filtered, received as pinhole transmitted light by the photoelectric converter 821, converted into a detection signal, and analyzed by the computer 823.

The computer 823 is connected to a modulator 814 that modulates on / off of the power source of the excitation light source 812, and calculates the flow rate of the sample solution and the concentration of the solute in the sample solution from the value of the signal intensity difference. Do.
JP 2000-356611 A

  However, in the measuring apparatus 800, since it is necessary to maintain the positional relationship between the probe 850 and the photoelectric converter 821 accurately, it is difficult to change the measurement position and the operability is poor.

  Further, in the measuring apparatus 800, it is necessary to put the sample solution into the flow path 811 that is at a narrow interval between the probe 850 and the photoelectric converter 821. That is, when the flow path 811 does not fit in the narrow space between the probe 850 and the photoelectric converter 821, for example, in the case of a deep container, it is necessary to immerse the probe 850 and / or the photoelectric converter 821 in the sample solution. However, since the photoelectric converter 821 is an electronic device, it is difficult to waterproof the photoelectric converter 821. Therefore, when the channel 811 is a deep sample container, the flow rate of the sample solution or the flow rate in the sample solution Measurement of solute concentration is difficult and operability is poor. Furthermore, when the sample solution contains a flammable substance, since the photoelectric converter 821 is an electronic device, the detection unit including the photoelectric converter 821 is immersed in the sample solution, and the solute concentration or / and the flow rate of the sample solution. Can not be measured.

  The first object of the present invention is to make it possible to easily change the measurement position and improve the operability, the probe for the measurement device, and the solute concentration of the liquid in the flow path and / or It is to provide a method for measuring a flow rate.

  A second object of the present invention is to provide a measuring device capable of measuring the solute concentration or / and flow velocity of a liquid even in a deep container, the probe for the measuring device, and the solute concentration of the liquid in the flow channel. Another object is to provide a method for measuring the flow rate.

  The third object of the present invention is to provide a measuring device capable of measuring the solute concentration or / and the flow velocity of a liquid by using a thermal lens by immersing the detection part in the liquid even if the liquid contains a flammable substance. An object of the present invention is to provide a probe for the measurement device and a method for measuring the solute concentration or / and the flow rate of the liquid in the flow path.

  In order to achieve the first to third objects, the measurement device according to claim 1 is a measurement device that measures the solute concentration or / and flow velocity of the liquid in the flow channel using a thermal lens. Excitation light irradiation means for irradiating a liquid with excitation light to form a thermal lens on the liquid, probe light irradiation means for irradiating the formed thermal lens with probe light, and probe light transmitted through the thermal lens Probe light reflecting means for reflecting in the liquid, detection means for detecting the reflected probe light outside the liquid, and measurement for measuring the solute concentration and / or the flow velocity based on the detected probe light Means.

  The measuring apparatus according to claim 2 is the measuring apparatus according to claim 1, wherein the probe light reflecting means is arranged in the vicinity of a focal point formed by the thermal lens of the irradiated excitation light. .

  The measuring apparatus according to claim 3 is the measuring apparatus according to claim 1 or 2, wherein the probe light irradiating means includes a probe light guide for guiding the probe light to the formed thermal lens, and the probe light reflecting means. Is configured to reflect the probe light irradiated from the probe light guide path toward the probe light guide path.

  The measurement apparatus according to claim 4 is the measurement apparatus according to claim 1 or 2, wherein the probe light irradiation unit includes a probe light guide path that guides the probe light to the formed thermal lens, and the detection unit includes: A reflected light guide that guides the reflected probe light, and the probe light reflecting means is configured to reflect the probe light emitted from the probe light guide toward the reflected light guide. To do.

  The measurement apparatus according to claim 5 is the measurement apparatus according to any one of claims 1 to 4, wherein the reflection means includes excitation light reflection suppression means for suppressing reflection of the irradiated excitation light. It is characterized by.

  A measuring apparatus according to a sixth aspect is the measuring apparatus according to any one of the first to fifth aspects, wherein the irradiated excitation light and the irradiated probe light are condensed and irradiated in the direction of the liquid. An optical lens is provided.

  In order to achieve the first to third objects, the probe according to claim 7 is a probe for a measuring device that measures the solute concentration or / and the flow velocity of the liquid in the flow path using a thermal lens, An excitation light guide that guides excitation light to the liquid in the flow path to form a thermal lens in the liquid, a probe light guide that guides probe light to the formed thermal lens, and probe light that passes through the thermal lens It is characterized by comprising a reflecting means for reflecting the light and a reflected light guide for guiding the reflected probe light.

  The probe according to claim 8 is the probe according to claim 7, wherein the excitation light guide, the probe light guide, and the reflected light guide are formed of a single common first optical fiber, and the reflection unit includes: It comprises a reflection mirror configured to reflect the probe light irradiated from the probe light guide path toward the first optical fiber.

  The probe according to claim 9 is the probe according to claim 7, wherein the excitation light guide and the probe light guide are made of a common first optical fiber, and the reflected light guide is made of a second optical fiber, The reflection means includes a reflection mirror configured to reflect the probe light irradiated from the probe light guide path toward the second optical fiber.

  The probe according to claim 10 is the probe according to any one of claims 7 to 9, further comprising a ferrule that supports the excitation light guide, the probe light guide, and the reflected light guide, and the excitation light. A rod lens that collects the excitation light guided by the optical path, the probe light guided by the probe light guide path, and the reflected probe light; and a fixed support that fixedly supports the ferrule and the rod lens. It is characterized by providing.

  The probe according to claim 11 is the probe according to any one of claims 7 to 9, wherein the probe optical waveguide guides the probe light in a single mode.

  In order to achieve the above first to third objects, the method for measuring the solute concentration or / and flow velocity of the liquid in the flow channel according to claim 12 uses a thermal lens to measure the solute concentration or / and flow velocity of the liquid in the flow channel. In the measurement method used for measurement, an excitation light irradiation step for irradiating the liquid in the flow path with excitation light to form a thermal lens on the liquid, and a probe light irradiation step for irradiating the formed thermal lens with probe light And a probe light reflecting step for reflecting the probe light transmitted through the thermal lens in the liquid, a detection step for detecting the reflected probe light outside the liquid, and the detected probe light. A measurement step of measuring the solute concentration or / and the flow rate.

  According to the measuring device according to claim 1, the probe for measuring device according to claim 7, or the method for measuring the solute concentration and / or flow velocity of the liquid in the flow channel according to claim 12, excitation light is applied to the liquid in the flow channel. Irradiate to form a thermal lens on the liquid, irradiate the formed thermal lens with probe light, reflect the probe light transmitted through the thermal lens in the liquid, and detect the reflected probe light outside the liquid Since the solute concentration and / or the flow velocity is measured based on the detected probe light, the measurement position can be easily changed, the operability can be improved, and a flammable substance is contained. Even if it is a liquid, a detection part can be immersed in a liquid and the solute density | concentration or / and flow velocity of a liquid can be measured using a thermal lens. Furthermore, even if the liquid is in a deep container, the solute concentration and / or flow rate of the liquid can be measured.

  According to the measurement apparatus of the second aspect, since the probe light that has passed through the thermal lens is reflected in the liquid in the vicinity of the focal point of the irradiated excitation light, the detection sensitivity of the measurement apparatus can be improved.

  According to the measuring apparatus according to claim 3 or the probe according to claim 8, since the irradiated probe light is reflected toward the probe light guide path that guides the irradiated probe light to the formed thermal lens, the probe The light guide path can be shared between the irradiation light and the reflected light, and the configuration of the measurement apparatus can be simplified.

  According to the measurement device according to claim 4 or the probe according to claim 9, since the probe light irradiated from the probe light guide is reflected toward the reflected light guide, the probe light guide and the reflected light guide are separately provided. The degree of freedom of arrangement of the probe light guide path and the reflected light guide path in the measurement apparatus can be improved.

  According to the measurement device of claim 5, since the reflection of the irradiated excitation light is suppressed, it is possible to reliably prevent the reflected light of the excitation light that becomes a noise component when detecting the probe light, The measurement accuracy of the measuring device can be improved.

  According to the measuring apparatus of the sixth aspect, the irradiated excitation light and the irradiated probe light are condensed and irradiated in the direction of the liquid, so that the detection sensitivity of the measuring apparatus can be improved.

  According to the probe of the eleventh aspect, since the probe light is guided in the single mode, the reproducibility of the measuring apparatus can be improved and the measurement accuracy can be improved.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram schematically showing the configuration of the measuring apparatus according to the first embodiment of the present invention.

  In FIG. 1, the measuring apparatus 1 has a light source module 100 having a connector 59a, and a light source module 100 that is immersed in a sample solution and collects excitation light and probe light on a sample solution (not shown) in a flow path 20 in detail. An optical fiber with lens (hereinafter referred to as “probe”) 50 and a signal processing unit 60 are provided. The probe 50 includes a connector 59b for detachably connecting to the light source module 100. The upper surface of the channel 20 is partially or entirely opened so that the probe 50 can be immersed in the sample solution in the channel 20.

  The light source module 100 includes an excitation light source 53 that emits excitation light, a modulation circuit 110 that modulates a power source of the excitation light source 53, a probe light source 51 that emits probe light, and an excitation light source 53. A multiplexer / demultiplexer 55 for multiplexing the excitation light of the probe and the probe light from the probe light source 51, a multiplexer / demultiplexer 56 for demultiplexing the probe light that has passed through the sample solution from the probe light from the light source 51, and Incident from the probe 50 side between the detector 54 composed of a photosensor such as a photodiode for receiving the probe light, the connector 59a enabling the attachment / detachment of the probe 50, the multiplexer / demultiplexer 56 and the probe light source 51. And an isolator 52 having a loss of light of 30 dB or more. The isolator 52 blocks light transmission by the polarization action of light.

  As the multiplexer / demultiplexer 56, a fusion coupler, a circulator, a filter module using a tap filter, or the like can be used. As the multiplexer / demultiplexer 55, a filter module using an edge filter or a bandpass filter can be used.

  The light source module 100 includes an optical fiber 106 that connects the excitation light source 53 and the multiplexer / demultiplexer 55, an optical fiber 107 that connects the connector 59a and the multiplexer / demultiplexer 55, a detector 54, and an multiplexer / demultiplexer. And an optical fiber 109 for connecting the probe light source 51, the isolator 52, and the multiplexer / demultiplexer 56. Thus, since the light source module 100 uses the optical fibers 106 to 109 to transmit the excitation light and / or the probe light, the light source module 100 can be simplified and miniaturized. Further, in the optical fiber 107 and the optical fiber 103 to be described later, the optical paths of the excitation light and the probe light are the same, so that the optical axes of the excitation light and the probe light need not be aligned. The optical fibers 103 and 107 guide the excitation light in a single mode. By using a single optical fiber, the distribution of light intensity is stabilized, and thus the measuring apparatus 1 can perform highly accurate measurement with high reproducibility. Accordingly, the focal point of the excitation light can be reduced, the thermal lens formed by the excitation light can be made a small lens, and the measurement accuracy of the measurement apparatus 1 can be improved.

  The modulation circuit 110 performs modulation from 100 Hz to 10 kHz on the excitation light source 53. Thereby, the detection sensitivity of probe light can be improved reliably.

  Preferably, an edge filter (not shown) that cuts off light having a wavelength longer than the wavelength of the excitation light and shorter than the wavelength of the probe light is provided at the end of the optical fiber 108. As a result, it is possible to reliably prevent the excitation light from entering the detector 54, thereby further improving the detection sensitivity of the measurement apparatus 1.

  The signal processing unit 60 includes a lock-in amplifier 61 connected to the detector 54 and the modulation circuit 110, and a computer 62 connected to the lock-in amplifier 61.

  FIG. 2 is an enlarged cross-sectional view showing in detail the configuration of the probe 50 in FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III in FIG.

  In FIG. 2, the probe 50 is a connector 59 b for connecting to the light source module 100, and guides the excitation light and the probe light from the light source module 100 through the connector 59 b and also transmits the probe light through the sample solution to the light source module 100. Optical fiber 103, a condensing lens 40 (rod lens) that condenses the excitation light and probe light guided by the optical fiber 103, a mirror 41 that reflects at least the probe light from the condensing lens, and a condensing lens 40. , A ferrule 43 for fixing the optical fiber 103 to the tube 42 so as to face the upper surface of the condenser lens 40, and the condenser lens 40. And the distance between the mirrors 41 at a predetermined length, for example, two struts 44 and a The bottom surface of over Bed 50 and a jig 45 for holding the adjustable probe 50 so as to face the passage 20. The optical fiber 103 and the condenser lens 40 may be in close contact with each other, or a gap may be provided between them. The reflecting surface of the mirror 41 is preferably a flat surface in that the flow rate of the sample solution does not change, and is preferably a curved surface in that the probe light is efficiently reflected.

  The condenser lens 40 is composed of a gradient index cylindrical rod lens provided with a refractive index gradient so that the refractive index decreases from the center toward the outside. Since this gradient index rod lens is much smaller than the microscope objective lens, the probe 50 can be miniaturized. Moreover, since the condensing lens 40 is cylindrical, that is, the upper surface and the bottom surface are flat, the assembly of the probe 50 including the attachment of the optical fiber 103 can be facilitated. Furthermore, since the condensing lens 40 is cylindrical, it can be easily fitted in the tube 42 and the optical axis can be easily aligned.

  As shown in FIG. 3, the support column 44 is provided so as to be parallel to the length direction of the flow path 20, that is, the direction in which the sample solution flows. Thereby, it can measure correctly, without changing the flow rate of a sample solution.

  FIG. 4 is an enlarged cross-sectional view of the mirror 41 in FIG.

As shown in FIG. 4, the mirror 41 includes a glass substrate 31 as a base, an aluminum (Al) thin film 32 formed on the upper surface of the glass substrate 31, and silicon dioxide (SiO ₂ ) formed on the upper surface of the Al thin film 32. ) A total reflection mirror (front surface mirror) that includes the protective film 33 and reflects both the excitation light and the probe light.

Further, since the wavelength of the excitation light and the wavelength of the probe light are different from the total reflection mirror, an optical multilayer film (edge filter) as a reflection film that selectively reflects the probe light and selectively transmits the excitation light. It is preferable to use a selective reflection mirror, which will be described later, in which a glass substrate 31 is coated on the glass substrate 31 because the amount of return of excitation light is greatly reduced. Note that the optical multilayer film of such a selective reflection mirror is composed of an alternating laminated film of a high refractive index oxide such as TiO ₂ or ZrO ₂ and a low refractive index oxide such as SiO ₂ .

  Next, the focus of excitation light and probe light from the light source module 100 will be described.

  FIG. 5 is a partially enlarged view of FIG. 2 used to explain the focal points of the excitation light and the probe light from the condenser lens 40 in FIG. In FIG. 5, hatching is omitted.

  In FIG. 5, the one-dot chain line indicates the optical path of the excitation light, the solid line indicates the optical path of the probe light when the excitation light is off, and the chain line indicates the optical path of the probe light when the excitation light is on. The focal points in the respective optical paths when there is no A are given by A, B, and C.

  The mirror 41 is disposed between the focal point A and the focal point B, or between the focal point A and the end surface of the condenser lens 40 on the mirror 41 side. When arranged between the focal point A and the end surface of the condenser lens 40 on the mirror 41 side, the reflected light of the excitation light preferably forms a focal point in the sample solution. When the mirror 41 is disposed between the focal points A and B, the mirror 41 is preferably disposed at a position close to the focal point A.

  In order to improve the detection sensitivity of the measurement apparatus, the distance between the focal point of the excitation light and the focal point of the probe light that has been focused and irradiated is preferably 20 μm or more and 200 μm or less.

  Next, the configuration of the light source module 100 will be described.

  FIG. 6 is a cross-sectional view showing the configuration of the multiplexer / demultiplexer 55 in FIG. 1 in detail.

  6, the multiplexer / demultiplexer 55 includes a rod lens 551 provided on the incident side of excitation light and reflected light (probe light reflected by the mirror 41), and a rod lens 552 provided on the incident side of probe light. And a long pass filter 553 provided between the rod lenses 551 and 552, which are connected in series. The multiplexer / demultiplexer 55 includes a rod lens 551, a long pass filter 553, and a tube 554 into which the rod lens 552 is internally connected.

  The long pass filter 553 includes a dielectric multilayer film formed by sequentially depositing on one surface of the rod lens 551, and the rod lens 552 is fixed to the upper surface of the dielectric multilayer film with an adhesive or the like. . The long pass filter 553 may be formed on a glass substrate in advance, and the glass substrate may be disposed between the rod lenses 551 and 552 and fixed with an adhesive or the like. Thus, since the multiplexer / demultiplexer 55 has a bonded structure, it can be made compact.

The dielectric multilayer film constituting the long pass filter 553 is composed of a low refractive index layer (L) made of SiO ₂ or the like and a high refractive index layer (H) made of TiO ₂ , ZrO ₂ , Ta ₂ O ₅ or the like. A set of LH layers are repeatedly laminated over multiple layers.

  FIG. 7 is a cross-sectional view showing the configuration of the multiplexer / demultiplexer 56 in FIG. 1 in detail.

  In FIG. 7, the multiplexer / demultiplexer 56 is configured using two refractive index distribution type cylindrical rod lenses 561 and 562 similar to the multiplexer / demultiplexer 55 and a tap filter 563. The rod lens 561 has an incident end face of reflected light emitted from one end of the multiplexer / demultiplexer 55, and the rod lens 562 has an incident end face of probe light emitted from one end of the probe light source 51. A part of the reflected light incident on the multiplexer / demultiplexer 56 is emitted from a place different from the incident place on the same surface as the incident end face of the rod lens 561.

  The tap filter 563 is interposed between the end surfaces of the rod lenses 561 and 562, and is composed of an optical multilayer film in which high-refractive index dielectric films and low-refractive index dielectric films are alternately stacked. The optical multilayer film has a so-called neutral filter characteristic in which the transmittance is approximately 50% in a wide wavelength range.

  Reflected light (probe light returning from the liquid (sample solution)) incident on the incident end face of the rod lens 561 at a position away from the center of the optical axis of the rod lens 561 travels in the rod lens 561 and advances. The reflected light corresponding to half of the reflected light is reflected by the optical multilayer film constituting the tap filter 563, and the reflected light is incident on the incident end face of the rod lens 561 with respect to the optical axis. Are emitted from symmetrical positions, guided to a detector 54 such as a photodetector (PD), and detected by the detector 54 as detection light.

  The probe light emitted from the probe light source 51 and incident on the incident end face of the rod lens 562 of the tap filter 563 via the isolator 52 passes through the tap filter 563 and becomes about half the light amount. The light exits from the incident end face.

  As shown in FIG. 1, the multiplexer / demultiplexer 55 in FIG. 6 and the multiplexer / demultiplexer 56 in FIG. 7 are connected to each other by an optical fiber 111, and the optical fiber 111 receives reflected light emitted from the multiplexer / demultiplexer 55. While guiding to the multiplexer / demultiplexer 56, the probe light emitted from the multiplexer / demultiplexer 56 is guided to the multiplexer / demultiplexer 55.

  Further, the incident end face of the rod lens 562 of the multiplexer / demultiplexer 56 and the isolator 52 are connected to the isolator 52 and the probe light source 51 by optical fibers 109 and 109, respectively.

  As described above, in the multiplexer / demultiplexer 56 of the light source module 100 of FIG. 1, approximately 50% of the incident light has an emission side (rod lens) opposite to the incident side (incident end surface of the rod lens 561). A tap filter 563 configured to transmit incident light corresponding to about 50% of the light amount from the incident side is used as the multiplexer / demultiplexer 56 of the light source module 100. May be a fusion-type coupler, a circulator, or the like. When the tap filter 563 is used as the multiplexer / demultiplexer 56 or when a fusion coupler is used as the multiplexer / demultiplexer 56, the multiplexer / demultiplexer 56 is connected in series with the probe light source 51 and the isolator 52. When a circulator is used as the multiplexer / demultiplexer 56, the isolator 52 need not be provided.

  Further, the dielectric multilayer film of the multiplexer / demultiplexer 55 described above has a transmittance of −3 dB or more (100˜) for light having a wavelength longer than the wavelength of the excitation light (probe light that has passed through the sample solution included in the reflected light). 50%), and the transmittance of the excitation light is −30 dB or less (0.1% or less), the probe light that has passed through the sample solution can be reliably demultiplexed from the reflected light from the optical fiber 107. .

  The rod lenses 551, 552, 561, and 562 are refractive index distribution type cylindrical rod lenses provided with a refractive index gradient so that the refractive index decreases from the center toward the outside. Since this gradient index rod lens is much smaller than the microscope objective lens, the multiplexer / demultiplexers 55 and 56 can be downsized. Further, since the rod lenses 551, 552, 561, and 562 are cylindrical, that is, the top and bottom surfaces are flat, it is easy to attach the optical fibers 106 to 109 and 111 and assemble the multiplexer / demultiplexers 55 and 56. be able to. Furthermore, since the rod lenses 551, 552, 561, and 562 are cylindrical, it is possible to easily align the optical axes.

  Hereinafter, a measurement method executed in the measurement apparatus 1 will be described.

  FIG. 8 is a flowchart of the measurement process executed by the measurement apparatus 1 of FIG.

  In FIG. 8, first, in step S <b> 701, the probe 50 is at least partially immersed in the sample solution flowing in the flow path 20. At the time of actual measurement, the probe 50 is immersed in the sample solution while being moved by the jig 45, and when the focal point of the excitation light is located in the sample solution, that is, by fixing the jig 45 at the target measurement position, The immersion depth for 41 sample solutions is determined. Depending on the amount of the sample solution, the probe 50 may be thrown into the sample solution. The probe 50 is designed so that the measurement is optimized in a state where the probe 50 is thrown into the sample solution, that is, in a state where the space between the condenser lens 40 and the mirror 41 is filled with the sample solution.

  In subsequent step S702, the sample solution is irradiated with the excitation light from the excitation light source 53 via the multiplexer / demultiplexer 55, the condensing lens 40 of the probe 50, etc., and a thermal lens is placed in the sample solution. Form (excitation light irradiation means). In some cases, the excitation light is modulated by the modulation circuit 110. Next, the sample solution is irradiated with the probe light from the probe light source 51 through the condenser lens 40 or the like (probe light irradiation means), and is transmitted through the thermal lens formed in the sample solution (step S703).

  In step S704, the mirror 41 reflects at least the probe light in the direction of the condensing lens 40 in the sample solution (reflecting means), and this reflected light is detected as a detection signal by the detector 54 (step S704). S705) (detection means). The detected detection signal is input to the signal processing unit 60. When the signal processing unit 60 measures the solute concentration of the sample solution based on the detection signal (YES in step S706), the calculation is performed. If the flow rate of the sample solution is measured (YES in step S708), the calculation is performed (step S709) (measuring means), and this process is terminated.

  In the measurement of the flow rate of the sample solution and the measurement of the concentration of the solute in the sample solution, the deviation of the focal position when the reflected light from the mirror 41 enters the optical fiber 103 again via the condenser lens 40 is detected by the probe 54. The signal processing unit 60 estimates the power of the thermal lens formed on the basis of the light power change, and the flow rate of the sample solution and the sample solution in the sample solution correspond to the estimated power of the thermal lens. The concentration of the solute is calculated.

  According to the process of FIG. 8, since the probe 50 is immersed in the sample solution (step S701), the measurement position can be easily changed even when the channel 20 is a deep container, and the operation is performed. The probe 50 as the detection unit can be immersed in the liquid even in the sample solution containing the flammable substance, and the mirror 41 collects at least the probe light in the sample solution. Since it reflects in the direction of 40 (step S704), the solute concentration and / or flow rate of the sample solution flowing in the flow path 20 can be measured.

Further, since a thermal lens is formed (step S703), the solute concentration and / or flow rate of the sample solution is measured even if the solute concentration in the sample solution is a low concentration of 10 ⁻⁷ mol / dm ³ level. Can do. This level is a detection limit that is about two orders of magnitude higher than the detection limit of conventional absorptiometry.

  Hereinafter, the solute concentration calculation process in step S707 and the flow velocity calculation process in step S709 in FIG. 8 will be specifically described.

  First, in the processing of steps S701 to S702 in FIG. 8, the excitation light emitted from the excitation light source 53 when the power is on is absorbed by the solute in the sample solution, and the amount of heat is the solvent of the sample solution. Move to. A thermal lens having a diameter of 2 to several μm is formed around the solute at the focal point of the excitation light in the solvent of the sample solution that has acquired the amount of heat.

  In step S703, the probe light emitted from the probe light source 13 passes through the thermal lens formed by the excitation light, and is detected as an electrical signal by the detector 54 via the reflection mirror 41 (step S705). ), The value of the signal intensity difference ΔI and the value of the phase shift θ described later are input to the computer 62 as measured values.

  FIG. 9 is a timing chart showing the relationship between the output of the modulation circuit 110 in FIG. 1 and the signal intensity I of the signal detected in step S705 in FIG. In FIG. 9, the value of the switching frequency f by the modulation circuit 110 is 1 kHz, the duty ratio is 50:50, and the value of the flow velocity v of the sample solution is 2 μm / msec.

As shown in FIG. 9, the signal intensity I of the signal detected in step S705 changes according to the optical refractive power of the thermal lens formed by the excitation light being absorbed by the solute in the sample solution, changes in synchronization with the period of 1,000 sec ^-1 is the inverse of the value 1kHz switching frequency f (sec ^-1) with respect to the excitation light source 53 by the modulation circuit 110.

The measuring apparatus 1 measures the signal intensity difference ΔI _A and the phase shift θ _A in FIG.

The signal strength difference ΔI refers to the absolute value | I ₀ −I ₁ | of the difference between the maximum signal strength I ₀ and the minimum signal strength I ₁ .

The phase shift θ is an index indicating the degree to which the phase of the probe light is delayed with respect to the switching-off phase, and the signal intensity I is a signal whose average value is, for example, the signal intensity difference ΔI. The unit until the intensity becomes I ₂ is an angle expressed in, for example, radians. The phase shift θ may be obtained based on the switching-on phase, or may be obtained based on the switching-on and switching-off phases.

  The optical refractive power of the thermal lens corresponding to the signal intensity I is gradually increased when the power source of the excitation light source 53 is turned on (thermal lens formation period A). Eventually, the optical refractive power of the thermal lens becomes constant. Actually, since the sample solution is fed at a predetermined flow rate, the thermal lens is in a steady state in which formation and diffusion are in a balanced state (thermal lens formation-diffusion balance period B). Thereafter, when the excitation light source 53 is turned off, the solute in the sample solution absorbs the excitation light and does not acquire heat, so that the thermal lens diffuses and the optical refractive power of the thermal lens gradually increases. After a while, the thermal lens disappears (thermal lens diffusion period C).

  Here, the following flow velocity parameters contribute to the diffusion of the thermal lens, that is, the decrease of the signal intensity I.

This flow velocity parameter is derived from the flow velocity v of the sample solution when the thermal lens moves from the focal position of the excitation light by the condenser lens 40 with the flow of the sample solution. As the value of the flow rate parameter v of the sample solution increases, the flow rate parameter contributes to the movement of the thermal lens, that is, to decrease the value of the signal intensity I, and the value of the phase shift θ also decreases as described later. The greater the contribution of this flow velocity parameter, the greater the degree of diffusion of the thermal lens and the smaller the signal intensity I ₀ value.

As described above, since the flow rate parameter contributes to the signal intensity difference ΔI and the phase shift θ, the flow rate v of the sample solution is calculated from one of the signal intensity difference ΔI _A and the phase shift θ _A in FIG. Can be calculated.

  FIG. 10 is a diagram showing the relationship between the signal intensity difference ΔI and the flow rate v of the sample solution.

  As shown in FIG. 10, the value of the signal intensity difference ΔI decreases as the value of the flow velocity v of the sample solution increases. It is preferable to store such a relationship between the signal intensity difference ΔI and the sample solution flow velocity v as a calibration curve. Thereby, the measuring apparatus 1 can calculate the value of the flow velocity v from the detected signal intensity difference ΔI based on the relationship of FIG.

  In addition, the said calibration curve is represented like the following formula 1, for example.

ΔI = m · v + P (1)
Here, m is a constant representing the slope in FIG. 10, P is a predetermined constant, and is preferably determined based on the value of the concentration c of the solute in the sample solution described later.

  FIG. 11 is a diagram illustrating the relationship between the phase shift θ and the flow velocity v of the sample solution.

  As shown in FIG. 11, the value of the phase shift θ decreases as the value of the sample solution flow velocity v increases. It is preferable to store the relationship between the phase shift θ and the sample solution flow velocity v as a calibration curve. Thereby, the measuring apparatus 1 can calculate the value of the flow velocity v from the detected phase shift θ based on the relationship of FIG.

  In addition, the said calibration curve is represented like the following formula 2, for example.

θ = m ′ · v + P ′ (2)
Here, m ′ is a constant representing the slope in FIG. 11, P ′ is a predetermined constant, and is preferably determined based on the value of the solute concentration c in the sample solution described later.

Further, since the flow rate parameter contributes to the signal intensity difference ΔI and the phase shift θ, the value of the flow velocity v of the sample solution can be calculated from both the value of the signal intensity difference ΔI _{A and} the value of the phase shift θ _A. Become.

  Note that the measurement process of FIG. 8 may be repeatedly executed, or the process of step S707 and / or step S709 may be executed over a plurality of periods and the results may be averaged.

  Hereinafter, a first modification of the measuring apparatus 1 of FIG. 1 will be described.

In the measurement apparatus 1 of FIG. 1, the mirror 41 is configured as a total reflection mirror. However, in the first modification, the mirror 41 selectively reflects only the probe light out of the excitation light and the probe light. Configure the mirror. In this case, the mirror 41 includes a base and a dielectric multilayer film formed on the upper surface of the base. The dielectric multilayer film is formed by alternately forming SiO ₂ thin films and TiO ₂ thin films (not shown) such as SiO ₂ thin film / TiO ₂ thin film / SiO ₂ thin film / TiO ₂ thin film /. Become. Thereby, only probe light can be selectively reflected among excitation light and probe light, and the measurement accuracy of the measuring apparatus 1 can be improved.

  When the mirror 41 constitutes a selective reflection mirror, the mirror 41 is disposed beyond the focal point A in FIG.

  Hereinafter, the 2nd modification of the measuring apparatus 1 of FIG. 1 is demonstrated.

  In the measurement apparatus 1 of FIG. 1, the mirror 41 is provided so as to face the condenser lens 40. However, in the second modification, a solvent-proofing process, for example, a waterproofing process is performed in advance instead of the mirror 41. A detector 54 is disposed. For example, by providing the detector 54 in a sealed structure such as a sealed container, the probe 50 and the detector 54 can be integrated. In this case, it is preferable to further simplify the configuration of the light source module 100. As a result, the configuration of the measuring apparatus 1 can be further simplified.

  In the present embodiment, the light source module 100 and the probe 50 are detachably connected to each other through the connectors 59a and 59b. However, the present invention is not limited to this. For example, the light source module 100 and the probe 50 are connected to each other. May be directly connected to each other via at least one optical fiber, or may be connected to each other by fusion bonding.

  In this embodiment, the modulation circuit 110 is used. However, the present invention is not limited to this, and any circuit may be used as long as it has an excitation light modulation mechanism that can improve detection sensitivity.

  In the present embodiment, a refractive index distribution type rod lens is used as the condenser lens 40, but a drum lens or the like may be used.

  In the present embodiment, the isolator 52 is provided between the multiplexer / demultiplexer 56 and the probe light source 51. However, when a circulator is used as the multiplexer / demultiplexer 56, it is not necessary to install the isolator 52.

  The second embodiment of the present invention will be described below.

  FIG. 12 is a block diagram schematically showing the configuration of the measuring apparatus according to the second embodiment of the present invention.

  The measurement apparatus 1 in FIG. 1 guides the reflected light to be detected to the detector 54 in the light source module 100 using the optical fibers 103, 107, and 108, whereas the measurement apparatus 1 ′ according to the present embodiment includes: 1 is different from the measuring apparatus 1 in FIG. 1 in that reflected light to be detected is guided directly from a probe to a detector in the light source module. Therefore, in the measurement apparatus 1 ′, the same components as those of the measurement apparatus 1 of FIG. 1 are denoted by the same reference numerals, description thereof will be omitted, and differences from the measurement apparatus 1 of FIG. 1 will be described.

  In FIG. 12, the measurement apparatus 1 ′ includes an optical fiber 113 that directly connects the detector 54 and the connector 59 a in the light source module 100. Further, the probe 50 is provided with an optical fiber 112 between the connector 59 b and the condenser lens 40 in order to guide the reflected light to the optical fiber 113. Thereby, for example, the optical fibers 107 and 103 can guide the excitation light and the probe light from the light sources 53 and 51, and the optical fibers 112 and 113 can guide the reflected light from the mirror 41 of the probe 50. The need to provide the duplexer 56 can be eliminated.

The measuring devices 1 and 1 ′ according to the embodiment of the present invention can be applied to a microchemical system, a flow velocity measuring device, and a concentration measuring device. Liquids to be measured include sample solutions that flow in the channels of microchemical systems, liquids in existing pipes, liquids in storage containers (tanks), purification facility waterways, wells, dams, and other urban facilities. There are natural waters such as water, rivers and lakes. The liquid to be measured may contain a flammable substance. Furthermore, the concentration of the solute in the liquid may be as low as 10 ⁻⁷ mol / dm ³ level. In addition, what the measurement devices 1 and 1 ′ perform in the measurement process include liquid flow rate measurement and / or solute concentration measurement in the liquid.

It is a block diagram which shows roughly the structure of the measuring apparatus which concerns on the 1st Embodiment of this invention. It is an expanded sectional view which shows the structure of the probe 50 in FIG. 1 in detail. It is sectional drawing which follows the line III-III in FIG. It is an expanded sectional view of the mirror 41 in FIG. FIG. 3 is a partially enlarged view of FIG. 2 used to explain the focal points of excitation light and probe light from the condenser lens 40 in FIG. 2. FIG. 2 is a cross-sectional view showing in detail a configuration of an multiplexer / demultiplexer 55 in FIG. 1. FIG. 2 is a cross-sectional view showing in detail a configuration of an multiplexer / demultiplexer 56 in FIG. 1. It is a flowchart of the measurement process performed by the measuring apparatus 1 of FIG. 8 is a timing chart showing the relationship between the output of the modulation circuit 110 in FIG. 1 and the signal intensity I of the signal detected in step S705 in FIG. It is a figure which shows the relationship between signal intensity difference (DELTA) I and the flow velocity v of a sample solution. It is a figure which shows the relationship between phase shift | offset | difference (theta) and the flow velocity v of a sample solution. It is a block diagram which shows roughly the structure of the measuring apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the conventional measuring apparatus roughly.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Measuring apparatus 20 Flow path 40 Condensing lens 41 Mirror 44 Support | pillar 50 Probe 55, 56 Multiplexer / demultiplexer 59a, b Connector 103,106-109,111-113 Optical fiber

Claims (12)

  In the measuring apparatus for measuring the solute concentration or / and flow velocity of the liquid in the flow path using a thermal lens, excitation light irradiation means for irradiating the liquid in the flow path with excitation light to form a thermal lens on the liquid, and Probe light irradiating means for irradiating the formed thermal lens with probe light, probe light reflecting means for reflecting the probe light transmitted through the thermal lens in the liquid, and the reflected probe light outside the liquid A measuring apparatus comprising: detecting means for detecting; and measuring means for measuring the solute concentration or / and the flow velocity based on the detected probe light.   The measuring apparatus according to claim 1, wherein the probe light reflecting means is disposed near a focal point formed by the thermal lens of the irradiated excitation light.   The probe light irradiating means includes a probe light guiding path that guides the probe light to the formed thermal lens, and the probe light reflecting means directs the probe light irradiated from the probe light guiding path toward the probe light guiding path. The measuring apparatus according to claim 1, wherein the measuring apparatus is configured to reflect light.   The probe light irradiation means includes a probe light guide path that guides the probe light to the formed thermal lens, the detection means includes a reflected light guide path that guides the reflected probe light, and the probe light reflection means includes: The measuring apparatus according to claim 1, wherein the probe light irradiated from the probe light guide path is configured to reflect toward the reflected light guide path.   The measurement apparatus according to claim 1, wherein the reflection unit includes excitation light reflection suppression unit that suppresses reflection of the irradiated excitation light.   The measurement apparatus according to claim 1, further comprising a condensing lens that condenses and irradiates the irradiated excitation light and the irradiated probe light in the direction of the liquid.   A probe for a measuring device for measuring a solute concentration or / and a flow velocity of a liquid in a flow path using a thermal lens, and an excitation light guide for guiding excitation light to the liquid in the flow path to form a thermal lens in the liquid; A probe light guide for guiding probe light to the formed thermal lens, a reflection means for reflecting the probe light transmitted through the thermal lens in the liquid, and a reflected light guide for guiding the reflected probe light. A probe characterized by that.   The excitation light guide path, the probe light guide path, and the reflected light guide path are composed of a single common first optical fiber, and the reflecting means applies the probe light emitted from the probe light guide path to the first optical fiber. The probe according to claim 7, comprising a reflection mirror configured to reflect toward the surface.   The excitation light guide path and the probe light guide path are composed of one common first optical fiber, the reflected light guide path is composed of a second optical fiber, and the reflecting means is adapted to emit probe light emitted from the probe light guide path. The probe according to claim 7, comprising a reflection mirror configured to reflect toward the second optical fiber.   Further, a ferrule that supports the excitation light guide, the probe light guide, and the reflected light guide, excitation light guided by the excitation light guide, probe light guided by the probe light guide, and the reflected probe The probe according to any one of claims 7 to 9, further comprising: a rod lens that collects light; and a fixed support that fixedly supports the ferrule and the rod lens.   The probe according to any one of claims 7 to 10, wherein the probe optical waveguide guides the probe light in a single mode.   In the measurement method of measuring the solute concentration or / and flow velocity of the liquid in the flow path using a thermal lens, the excitation light irradiation step of irradiating the liquid in the flow path with excitation light to form a thermal lens on the liquid; A probe light irradiation step of irradiating the formed thermal lens with probe light, a probe light reflection step of reflecting the probe light transmitted through the thermal lens in the liquid, and the reflected probe light outside the liquid A method for measuring the solute concentration or / and flow velocity of the liquid in the flow path, comprising: a detection step for detecting; and a measurement step for measuring the solute concentration or / and the flow velocity based on the detected probe light. .

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