Fluorescence measurement equipment

Abstract

To provide a fluorescence measuring device having a simple configuration.SOLUTION: A fluorescence measuring device measures concentration of a measurement object under measured water, and includes a measurement room for storing the measured water, a light projection path for projecting light in a first direction toward the measurement room, a measurement optical path for emitting light in a direction differing from the first direction from the measurement room, a transmission optical path for emitting light onto an extension line of the light projection path from the measurement room, a first light source for projecting first measurement light having a first wavelength for exciting the measurement object in the measurement room through the light projection path and generating fluorescence, a second light source for projecting second measurement light having a second wavelength that is identical or approximate to a wavelength of the fluorescence of the measurement object into the measurement room through the light projection path, a first light receiving element for receiving light emitted from the measurement optical path, a second light receiving element for receiving light emitted from the transmission optical path, and a light quantity adjustment mechanism for adjusting an amount of light projection from at least one of the first light source and the second light source to the measurement room.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fluorescence measuring device. [Background technology]

[0002] A known method for verifying water quality involves projecting measurement light of a wavelength that excites the target substance into the water to produce fluorescence, measuring the fluorescence of the target substance using a light-receiving element positioned so that the measurement light does not directly strike the target substance, and calculating the target substance's concentration. If the target substance contains components that scatter or absorb light, such as turbidity, in addition to the target substance, the amount of light received by the light-receiving element is affected by these components. For this reason, a device has been proposed that projects light of a wavelength that does not excite the target substance, measures the transmitted light and scattered light, and, based on these measurements, corrects for errors due to light scattering and absorption by components other than the target substance that may be included in the fluorescence measurement (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6436266 Summary of the Invention [Problem to be solved by the invention]

[0004] The fluorescence measuring device described in Patent Document 1 has a complex configuration in which a light source for measuring fluorescence and a light source for measuring scattered light are arranged so that they can project light coaxially onto the water to be measured, and requires a first detector that detects fluorescence at an angle of 90° based on this projection position, a second detector that detects transmitted light at an angle of 180°, and a third detector that detects scattered light at an angle of 270°.

[0005] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fluorescence measuring device with a simple configuration. [Means for solving the problem]

[0006] A fluorescence measuring device according to one embodiment of the present invention is a fluorescence measuring device that measures the concentration of a measurement target in measurement water, and comprises: a measurement chamber that stores the measurement water; a light projection path that projects light into the measurement chamber in a first direction; a measurement light path that emits light from the measurement chamber in a direction different from the first direction; a transmission light path that emits light from the measurement chamber on an extension of the light projection path; a first light source that projects first measurement light of a first wavelength into the measurement chamber through the light projection path to excite the measurement target and generate fluorescence; a second light source that projects second measurement light of a second wavelength that is identical to or similar to the wavelength of the fluorescence of the measurement target into the measurement chamber through the light projection path; a first light receiving element that receives light emitted from the measurement light path; a second light receiving element that receives light emitted from the transmission light path; and a light intensity adjustment mechanism that adjusts the amount of light projected into the measurement chamber from at least one of the first light source and the second light source.

[0007] In the above-described fluorescence measuring device, the light amount adjusting mechanism may have a diaphragm that limits the optical path of at least one of the first light source and the second light source.

[0008] In the above-described fluorescence measuring device, the first light source and the second light source may be disposed adjacent to each other on the same substrate.

[0009] The above-described fluorescence measuring device may further include a filter that removes the first wavelength component from the light emitted from the measurement optical path.

[0010] The above-mentioned fluorescence measuring device may further include a lid portion that can be opened and closed on the measurement chamber, and an open determination portion that determines that the lid portion is in an open state when the first light receiving element detects light equal to or greater than a predetermined threshold.

[0011] The above-mentioned fluorescence measuring device may further include a lid portion that can be opened and closed on the measurement chamber, and an open determination portion that determines that the lid portion is in an open state if the first light receiving element or the second light receiving element detects light when the first measurement light and the second measurement light are not projected. [Effects of the Invention]

[0012] According to the present invention, a fluorescence measuring device with a simple configuration can be provided. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing the configuration of a fluorescence measuring device according to one embodiment of the present invention. [Figure 2] 2 is a flowchart showing a procedure for measuring concentration using the fluorescence measuring device of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram showing the configuration of a fluorescence measuring device 1 according to one embodiment of the present invention. Note that the shapes of the components of the fluorescence measuring device 1 shown in the drawing are simplified, and the dimensions of each component have been adjusted for easy viewing.

[0015] The fluorescence measuring device 1 measures the concentration of a target substance in measurement water. The fluorescence measuring device 1 includes a housing 10, a light projecting unit 20, a first light receiving unit 30, a second light receiving unit 40, a supply line 50, a discharge line 60, and a control device 70.

[0016] The housing 10 is composed of a main container 11 made of a light-blocking material, and a lid 12 made of a light-blocking material and removably attached to the main container 11. As an example, the lid 12 can be formed in the shape of a plug having an external thread 121 that screws into an internal thread 111 formed at the opening of the main container 11.

[0017] The housing 10 has a measurement chamber 13 for storing the water to be measured, a light projection path 14 for projecting light into the measurement chamber 13 in a first direction, a measurement light path 15 for emitting light from the measurement chamber 13 in a direction different from the first direction, a transmission light path 16 for emitting light from the measurement chamber 13 on an extension of the light projection path 14, a supply flow path 17 to which a supply line 50 is connected, and a discharge flow path 18 to which a discharge line 60 is connected.

[0018] The light projection path 14, the measurement light path 15, and the transmitted light path 16 are configured to transmit at least the first measurement light and the second measurement light described below without causing the water to be measured to flow out of the measurement chamber 13. For example, the light projection path 14, the measurement light path 15, and the transmitted light path 16 may be defined by holes formed in the housing 10 so as to communicate with the measurement chamber 13, and at least the ends on the measurement chamber 13 side may be sealed with a light-transmitting material. The light projection path 14, the measurement light path 15, and the transmitted light path 16 are preferably formed by straight holes with small cross sections so as to limit the incident and outgoing directions of light.

[0019] The projection light path 14 and the transmitted light path 16 are formed coaxially on both sides of the measurement chamber 13. The measurement light path 15 is formed so that its axis intersects the axes of the projection light path 14 and the transmitted light path 16. It is preferable that the axis of the measurement light path 15 is perpendicular to the axes of the projection light path 14 and the transmitted light path 16. It is also preferable that the axis of the measurement light path 15 intersects the axes of the projection light path 14 and the transmitted light path 16 at the center of the measurement chamber 13. It is also preferable that the projection light path 14, the measurement light path 15, and the transmitted light path 16 are arranged so that the length of the optical path from the projection light path 14 to the measurement light path 15 is equal to the length of the optical path from the projection light path 14 to the transmitted light path 16. In FIG. 1, in order to show the entire configuration, the axes of the projection path 14, measurement path 15, and transmission path 16 are shown to lie in the same vertical plane, but in reality, it is assumed that the axes of the projection path 14, measurement path 15, and transmission path 16 will be arranged to lie in the same horizontal plane.

[0020] The measurement chamber 13 is defined as the internal space of the main container 11, and has an openable and closable lid portion 131 formed by the lid body 12. By opening the lid portion 131, maintenance such as cleaning of the inside of the measurement chamber 13 becomes possible.

[0021] The supply flow path 17 is preferably formed so as to open to the bottom of the measurement chamber 13, and the discharge flow path 18 is preferably formed so as to open to the top of the measurement chamber 13. This allows the measurement water in the measurement chamber 13 to be efficiently replaced. The discharge flow path 18 is formed so as to allow old measurement water to overflow from the top of the measurement chamber 13 into a drainage system.

[0022] The light-projecting unit 20 includes a first light source 21 that projects a first measurement light of a first wavelength (e.g., ultraviolet light of 365 nm) through the light-projecting path 14 into the measurement chamber 13 to excite the measurement target in the measured water and generate fluorescence, a second light source 22 that projects a second measurement light of a second wavelength (e.g., violet light of 420 nm) that is the same as or similar to the wavelength of the fluorescence of the measurement target through the light-projecting path 14 into the measurement chamber 13, a light-projecting circuit board 23 on which the first light source 21 and the second light source 22 are mounted and that supplies power to the first light source 21 and the second light source 22 as needed, and a light-intensity adjusting mechanism 24 that adjusts the amount of light projected from at least one of the first light source 21 and the second light source 22 (the second light source 22 in the illustrated example) into the measurement chamber 13. The light-projecting unit 20 preferably includes a light-projecting unit cover 25 that prevents external light from entering the light-projecting path 14.

[0023] The first light source 21 and the second light source 22 are typically configured with light-emitting diodes. The first light source 21 and the second light source 22, which are small elements such as light-emitting diodes, can be arranged adjacent to each other on the same light-projection circuit board 23. Although the first light source 21 and the second light source 22 are illustrated large in FIG. 1 , in reality, the first light source 21 and the second light source 22 can be small enough to be considered to be in the same position and arranged close to each other. By arranging the tiny first light source 21 and the second light source 22 adjacent to each other in this manner, the optical axis of the first measurement light and the optical axis of the second measurement light can be substantially aligned, thereby reducing measurement errors that may occur due to differences in the incident directions of the first measurement light and the second measurement light.

[0024] The light projecting circuit board 23 functions to hold the first light source 21 and the second light source 22 in a position where they can project measurement light into the measurement chamber 13 through the light projecting path 14. The light projecting circuit board 23 also has a drive circuit that selectively causes the first light source 21 or the second light source 22 to emit light in accordance with a command signal from the control device 70.

[0025] The light intensity adjustment mechanism 24 limits the light intensity of either the first light source 21 or the second light source 22 so that the intensity of the fluorescence of the measurement object incident on the first light receiving unit 30 when the first measurement light is projected and the intensity of the scattered light incident on the first light receiving unit 30 due to coloration of the water being measured when the second measurement light is projected are both within the measurable range of the first light receiving unit 30. In the illustrated example, the light intensity adjustment mechanism 24 is arranged to limit the intensity of the second measurement light. However, depending on, for example, the type of measurement object, the wavelengths of the first and second measurement lights, and the specifications of the first and second light sources 21 and 22, the light intensity adjustment mechanism 24 may be arranged to limit the intensity of the first measurement light, or may be arranged to limit the intensity of both the first and second measurement lights individually. Note that the measurement range of the concentration of the measurement object and the expected range of scattering degree can be set arbitrarily.

[0026] The light amount adjustment mechanism 24 may be a circuit or the like that is incorporated into a drive circuit formed on the light-projecting circuit board 23 and adjusts the power supplied to the first light source 21 or the second light source 22, but a simpler configuration may be an aperture that limits the cross-sectional area of ​​the light path, as shown in the figure. By using an aperture as the light amount adjustment mechanism 24, the configuration is simple and it is possible to easily bring the intensity of the fluorescent light received by the first light-receiving unit 30 close to the intensity of the scattered light.

[0027] The first light receiving unit 30 has a first light receiving element 31 that receives light emitted from the measurement light path 15 and generates an electrical signal according to the intensity of the light, a first detection circuit board 32 on which the first light receiving element 31 is mounted, and a filter 33 that removes a first wavelength component from the light emitted from the measurement light path 15. The first light receiving unit 30 preferably has a first light receiving unit cover 34 that prevents external light from entering the measurement light path 15.

[0028] The first light-receiving element 31 is typically configured with a photodiode. The first detection circuit board 32 has a detection circuit that amplifies the signal output by the first light-receiving element 31, converts it into a digital signal as necessary, and outputs a detection signal to be input to the control device 70. The filter 33 blocks light in a wavelength range including the first wavelength while transmitting light in a wavelength range close to the second wavelength. This allows the first light-receiving element 31 to detect the intensity of light of the second wavelength emitted from the measurement optical path 15. In other words, by providing the filter 33, when the first measurement light is transmitted through the measurement chamber 13, the first light-receiving element 31 does not receive scattered light of the first measurement light due to coloring, and can detect only the intensity of the fluorescence of the measurement object. This allows for accurate measurement of the amount of fluorescence and more accurate calculation of the concentration of the measurement object.

[0029] The second light receiving unit 40 detects the light intensity of the first measurement light and the second measurement light that are emitted from the measurement chamber 13 through the transmitted light path 16. That is, the second light receiving unit 40 detects the intensity of the first measurement light or the second measurement light that has traveled straight through without being absorbed or reflected by the measurement object. The second light receiving unit 40 includes a second light receiving element 41 that receives the light that is emitted from the transmitted light path 16 and generates an electrical signal corresponding to the intensity of the light, and a second detection circuit board 42 on which the second light receiving element 41 is mounted. The second light receiving unit 40 preferably includes a second light receiving unit cover 43 that prevents external light from entering the transmitted light path 16.

[0030] The second light receiving element 41 is typically configured with a photodiode, similar to the first light receiving element 31. The second detection circuit board 42, similar to the first detection circuit board 32, has a detection circuit that amplifies the signal output by the second light receiving element 41 and converts it into a digital signal as necessary, thereby outputting a detection signal to be input to the control device 70. The second light receiving unit 40 detects the intensity of the first measurement light or the second measurement light that has traveled straight without being absorbed or reflected by the measurement object.

[0031] The supply line 50 supplies the test water to be newly measured from the supply flow path 17 to the measurement chamber 13. The supply line 50 has an on-off valve 51 that is controlled by the control device 70 and cuts off the supply of the test water.

[0032] The discharge line 60 discharges the measured sample water from the measurement chamber 13. Specifically, the discharge line 60 extends downward from the discharge flow path 18 so as to allow the sample water to overflow when new sample water is supplied from the supply line 50.

[0033] The control device 70 controls the light-projecting unit 20 and the supply line 50, and calculates the concentration of the target substance in the water to be measured from the intensity of the light received by the first light-receiving element 31 and the second light-receiving element 41. The control device 70 can be realized by causing a computer device having, for example, a memory, a CPU, an input / output interface, etc. to execute an appropriate program.

[0034] The control device 70 includes a measurement control unit 71, a concentration calculation unit 72, a constantly open determination unit 73, and an open-during-pause determination unit 74. Note that the measurement control unit 71, the concentration calculation unit 72, the constantly open determination unit 73, and the open-during-pause determination unit 74 are merely classifications of the functions of the control device 70, and do not necessarily have to be clearly distinguishable in terms of physical configuration and program configuration.

[0035] The measurement control unit 71 causes the first light source 21 and the second light source 22 of the light projecting unit 20 to project measurement light in turn, and causes the concentration calculation unit 72 to calculate the concentration of the target substance in the measurement water based on the detection values ​​of the first light receiving unit 30 and the second light receiving unit 40. Furthermore, before the light projecting unit 20 projects measurement light and the concentration calculation unit 72 calculates the concentration of the target substance, the measurement control unit 71 opens the on-off valve 51 for a predetermined time, thereby replacing the measurement water in the measurement chamber 13. Furthermore, the measurement control unit 71 prohibits the on-off valve 51 from opening while at least one of the constantly open determination unit 73 and the idle open determination unit 74 determines that the lid 131 of the measurement chamber 13 is in an open state.

[0036] The basic concept is that the light of the second wavelength received by the first light receiving element 31 when the first measurement light is projected from the first light source 21 is due to the fluorescence of the analyte in the measurement water, and therefore the concentration of the analyte in the measurement water can be calculated from the light intensity received by the first light receiving element 31 when the first measurement light is projected. However, along the optical path in the measurement water from the light projection path 14 to the measurement light path 15, the first measurement light and the fluorescence of the analyte are absorbed by the analyte, color, etc., and the light intensity received by the first light receiving element 31 may not accurately correspond to the concentration of the analyte. For this reason, the concentration calculation unit 72 corrects errors in the light intensity received due to absorption and scattering based on the light intensity received by the second light receiving element 41 when the first measurement light is projected, and the light intensity received by the first light receiving element 31 and the second light receiving element 41 when the second measurement light is projected, to accurately calculate the concentration of the analyte.

[0037] 2 shows the procedure for measuring the concentration of a measurement target in the fluorescence measuring device 1, which is controlled by the control device 70. The concentration measurement includes a first wavelength measurement step (step S1), a second wavelength measurement step (step S2), a reference concentration calculation step (step S3), a first wavelength absorbance calculation step (step S4), a second wavelength absorbance calculation step (step S5), an absorbance correction step (step S6), a scattering degree calculation step (step S7), and a scattering degree correction step (step S8).

[0038] In the first wavelength measurement step S1, the first light source 21 emits a first measurement light beam having a first wavelength, and the light reception intensities of the first light receiving element 31 and the second light receiving element 41 are measured.

[0039] In the second wavelength measurement step S2, the second light source 22 projects second measurement light of the second wavelength, and the light reception intensities of the first light receiving element 31 and the second light receiving element 41 are measured.

[0040] In the reference concentration calculation step of step S3, a reference concentration is calculated, which is the concentration of the object to be measured assuming that there is no light absorption due to coloring or the like, based on the light intensity received by the first light receiving element 31 measured in the first wavelength measurement step. Specifically, the reference concentration can be calculated as a value proportional to the light intensity received by the first light receiving element 31 measured in the first wavelength measurement step. The reference concentration calculated here is a value that includes errors due to the influence of coloring or the like.

[0041] In the first wavelength absorbance calculation step of step S4, the first absorbance, which is the absorbance of the first wavelength of the water to be measured, is calculated based on the light intensity received by the second light receiving element 41 measured in the first wavelength measurement step. Specifically, the first absorbance of the water to be measured can be calculated from the ratio of the light intensity received by the second light receiving element 41 measured in the first wavelength measurement step to the light intensity received by the second light receiving element 41 (blank) measured in advance with pure water stored in the measurement chamber 13. Note that the first absorbance calculated here does not indicate a strictly accurate degree of light absorption and may include errors due to light scattering.

[0042] In step S5, a second wavelength absorbance calculation step, a second absorbance, which is the absorbance of the water to be measured at the second wavelength, is calculated using a method similar to that used in the first wavelength measurement step, based on the light intensity measured in the second wavelength measurement step by the second light receiving element 41. This second absorbance may also include errors due to light scattering.

[0043] In the absorbance correction step of step S6, the reference concentration calculated in the reference concentration calculation step is corrected by the first absorbance calculated in the first wavelength absorbance calculation step and the second absorbance calculated in the second wavelength absorbance calculation step. The decrease in the light intensity received by the first light receiving element 31 due to light absorption in the first wavelength measurement step can be considered to be divided into absorption of the first measurement light by the water under test along the light path from the light projection path 14 to the center of the measurement chamber 13 (the intersection of the axis of the light projection path 14 and the axis of the measurement light path 15), and absorption of fluorescence by the water under test along the light path from the center of the measurement chamber 13 to the measurement light path 15.

[0044] Therefore, the absorbance of the first measurement light in the optical path from the projection path 14 to the center of the measurement chamber 13 can be corrected based on the first absorbance, and the absorbance of the fluorescence in the optical path from the center of the measurement chamber 13 to the measurement optical path 15 can be corrected based on the second absorbance. To facilitate calculation, it is preferable that the optical path length from the projection path 14 to the center of the measurement chamber 13, the optical path length from the center of the measurement chamber 13 to the transmission optical path 16, and the optical path length from the center of the measurement chamber 13 to the measurement optical path 15 are equal.

[0045] In the scattering degree calculation process of step S7, based on the light receiving intensity of the first light receiving element 31 measured in the second wavelength measurement process, a scattering degree is calculated that indicates an offset in the light receiving intensity of the first light receiving element 31 that occurs when fluorescence excited in an area other than the center of the measurement chamber 13 reaches the first light receiving element 31 due to light scattering in the water to be measured.

[0046] In the scattering degree correction step of step S8, the value obtained by correcting the reference concentration in the absorbance correction step is further corrected based on the scattering degree calculated in the scattering degree calculation step, thereby allowing the accurate value of the concentration of the target substance in the measurement water to be calculated.

[0047] The always-open determination unit 73 determines that the lid 131 of the measurement chamber 13 is in an open state when the first light receiving element 31 detects light equal to or greater than a predetermined threshold. In other words, when the first light receiving element 31 detects light equal to or greater than a threshold that is set in advance as a reference value for determining that the maximum amount of light that the first light source 21 and the second light source 22 can emit exceeds a threshold assumed to be the maximum amount of light that the first light receiving element 31 can receive, the always-open determination unit 73 determines that the lid 12 is removed and that external light is entering the first light receiving element 31 through the measurement chamber 13 and the measurement light path 15.

[0048] The pause open determination unit 74 determines that the lid portion 131 of the measurement chamber 13 is in an open state when the first light receiving unit 30 or the second light receiving unit 40 detects light when the light projecting unit 20 is not projecting measurement light (first measurement light and second measurement light), that is, when at least one of the first light receiving element 31 and the second light receiving element 41 receives light.

[0049] As described above, the fluorescence measuring device 1, which comprises a measurement chamber 13 for storing the water to be measured, a light projection path 14 for projecting light into the measurement chamber 13 in a first direction, a measurement light path 15 for emitting light from the measurement chamber 13 in a direction different from the first direction, a transmission light path 16 for emitting light from the measurement chamber 13 on an extension of the light projection path 14, a first light source 21 for projecting a first measurement light of a first wavelength into the measurement chamber 13 through the light projection path 14 to excite the object to be measured and cause it to fluoresce, a second light source 22 for projecting a second measurement light of a second wavelength that is identical to or close to the wavelength of the fluorescence of the object to be measured through the light projection path 14 into the measurement chamber 13, a first light receiving element 31 for receiving the light emitted from the measurement light path 15, and a second light receiving element 41 for receiving the light emitted from the transmission light path 16, can measure the concentration of the object to be measured relatively accurately, taking into account the absorption and diffusion of light in the water to be measured.

[0050] Furthermore, the fluorescence measuring device 1 is equipped with a light intensity adjustment mechanism 24 that adjusts the amount of light projected from at least one of the first light source 21 and the second light source 22 into the measurement chamber 13, so that the intensity of the fluorescence of the measurement object when the first measurement light is projected and the intensity of scattered light due to coloration or the like when the second measurement light is projected can be kept within the measurable range of the first light receiving element 31. Therefore, the fluorescence measuring device 1 can measure the intensity of fluorescence and the intensity of scattered light using the same first light receiving element 31, so the number of light receiving elements is small and the configuration is simple. Furthermore, because the fluorescence measuring device 1 measures the intensity of fluorescence and the intensity of scattered light along the same optical path, measurement errors due to partial contamination of the device are less likely to occur.

[0051] In addition, the fluorescence measuring device 1 is equipped with a constant open determination unit 73 and an inactive open determination unit 74 that detect the opening of the lid portion 131 of the measurement chamber 13, so that the fluorescence measuring device 1 can prevent the problem of the measured water being sprayed out from the open lid portion 131 when new measured water is supplied from the supply line 50 to the measurement chamber 13 while the lid portion 131 is open.

[0052] Furthermore, the fluorescence measuring device 1 opens the on-off valve 51 for a predetermined time before projecting the measurement light, and measures the concentration by projecting the measurement light with the on-off valve 51 closed. This shortens the time that the on-off valve 51 is open, thereby reducing the risk of accidentally opening the lid portion 131 while the on-off valve 51 is open.

[0053] Furthermore, the fluorescence measuring device 1 is provided with an amplifier circuit on the first detection circuit board 32 and the second detection circuit board 42 that amplifies the detection signals of the light receiving units 30, 40, so that the intensity of the measurement light can be set low and the detection sensitivity to external light can be relatively improved, thereby more reliably detecting the opening of the lid unit 131.

[0054] Although the preferred embodiments of the fluorescence measuring device of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified as appropriate.

[0055] For example, a calculation formula may be used that directly calculates the concentration of the object to be measured by substituting the detected value of the received light intensity, without calculating at least one of the reference concentration, the first absorbance, the second absorbance, and the scattering index.

[0056] In addition, in cases where it is difficult to provide a filter that blocks only the light of the first wavelength without blocking the light of the second wavelength, a filter may not be provided in the first measurement unit, and correction may be performed assuming that the degree of scattering at the second wavelength calculated from the measurement value using the second measurement light is approximately the same as the degree of scattering at the first wavelength. [Explanation of symbols]

[0057] 1. Fluorescence measurement device 10. Housing 11 Main container 111 Internal thread 12 Lid 121 External thread 13 Measurement room 131 Lid 14 Projection path 15 Measurement optical path 16 Transmitted optical path 17 Supply channel 18 Exhaust flow path 20 Light projector 21 1st light source 22 Second light source 23 Light emitter circuit board 24 Light intensity adjustment mechanism 25 Translucent cover 30 1st light receiving section 31 First light receiving element 32 First detection circuit board 33 Filters 34 First light receiving unit cover 40 2nd light receiving section 41 Second light receiving element 42 Second detection circuit board 43 Second light receiving unit cover 50 Supply Lines 51 On-off valve 60 Discharge Line 70 Control device 71 Measurement control section 72 Concentration calculation section 73 Always open determination unit 74 Open judgment section during rest

Claims

1. A fluorescence measurement device for measuring the concentration of a target substance in test water, a measurement chamber for storing the water to be measured; a light projection path that projects light into the measurement chamber in a first direction; a measurement optical path that emits light from the measurement chamber in a direction different from the first direction; a transmission light path for emitting light from the measurement chamber along an extension of the projection light path; a first light source that projects a first measurement light having a first wavelength through the light projection path into the measurement chamber to excite the measurement object and generate fluorescence; a second light source that projects second measurement light having a second wavelength that is the same as or similar to the wavelength of the fluorescence of the measurement object into the measurement chamber through the light projection path; a first light receiving element that receives light emitted from the measurement optical path; a second light receiving element that receives light emitted from the transmitted light path; a light amount adjustment mechanism that adjusts the amount of light projected from at least one of the first light source and the second light source into the measurement chamber; Equipped with the first light source and the second light source are disposed adjacent to each other on the same substrate such that an optical axis of the first measurement light and an optical axis of the second measurement light are substantially aligned with each other; The light amount adjusting mechanism has a diaphragm that limits the optical path of at least one of the first light source and the second light source.

2. The fluorescence measurement device according to claim 1 , further comprising a filter that removes the first wavelength component from the light emitted from the measurement optical path.

3. 3. The fluorescence measuring device according to claim 1, further comprising a constantly open determining unit that determines that the measurement chamber is in an open state when the first light receiving element detects light of a predetermined threshold value or more.

4. 4. The fluorescence measuring device according to claim 1, further comprising an open state determination unit during rest that determines that the measurement chamber is in an open state if the first light receiving element or the second light receiving element detects light when the first measurement light and the second measurement light are not projected.

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