JP2012037356A - Fluorescence detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescence detector capable of sufficiently suppressing noise by reflected light and disturbance light which are mixed in during detection and stably obtaining highly accurate detection output.SOLUTION: A system in which a device body part 110 can be floated by a float part 120 is adopted. Further, a first angle θ21 with a vertical line passing through the intersection of the optical axis of excitation light irradiation from an excitation light irradiation part 130 and a water surface 11 and a second angle θ22 with a vertical line passing through the intersection of a receiving optical axis in a photodetection part 140 and the water surface 11 are such that the overlaps SA1 and UWc of irradiation areas EA1 and UW1 on the water surface and in the water of the excitation light from the excitation light irradiation part 130 and areas FA1 and UW2 on the water surface and in the water of a light receiving visual field in the photodetection part 140 occupy the majority of the irradiation areas EA1 and UW1 of the excitation light, and the reflected light on the water surface is not made incident on the photodetection part 140. A detection output level from the photodetection part 140 is relatively high and the influence of the disturbance light is not easily received.

Description

  The present invention relates to a fluorescence detection apparatus that detects a substance such as oil that floats on a water surface such as a water purification pond of a water purification plant or a factory effluent, or exists in water.

Spills of chemicals and oil in the sea and rivers cause serious damage to the environment. In particular, since oil spills occur relatively frequently, it is necessary to constantly monitor the water quality in factory drainage facilities to prevent large-scale spill accidents.
A reflection type detection device applied to the water quality monitoring as described above has already been proposed (see, for example, Patent Document 1). In the reflective detection device proposed in Patent Document 1, laser light is projected onto a substance that floats on the water surface, and oil that floats on the water surface based on the difference in reflectance between the water surface and the oil surface related to the laser light. The substance is detected.

On the other hand, in addition to oil floating on the water surface, substances such as oil existing in water need to be detected. For detecting substances such as oil that exist in water in this way, detection using differences in light reflectance cannot be performed, so chemical oxygen demand, which is one of the indicators of water pollution The presence or absence of oil in water is determined by measuring (COD).
However, since it takes time to measure the COD, there is a problem that it cannot be adapted for monitoring a leakage accident or the like that requires quick response.

In order to solve such a problem, there exists a method for detecting fluorescence emitted from a fluorescent substance such as oil. According to this method, a substance such as oil can be detected instantaneously.
However, with this method, it is difficult to stably obtain a detection output at all times because fluctuations in the detection distance affect the fluorescence intensity under conditions where the water level fluctuation is large.
Therefore, at present, a so-called float type fluorescence detection apparatus has been proposed in which detection is performed by floating the detection apparatus on the water surface in order to keep the detection distance constant. The fluorescence detection apparatus described in Patent Document 2 corresponds to this float type.

The float type fluorescence detection apparatus is excellent in that the detection output can be stabilized and high detection sensitivity can be obtained by bringing the detection apparatus itself close to the water surface.
However, in the conventional float type fluorescence detection apparatus, when detecting a substance with low fluorescence or a substance with low concentration, the detection sensitivity is still insufficient, and further enhancement of sensitivity has been demanded.

In addition, in conventional fluorescence detection devices, including those of the float type, disturbance light such as excitation light or sunlight from the water surface or underwater acts as reflection noise, which causes a decrease in detection sensitivity or causes false detection. It was.
The reflection noise from the water surface is generated when the excitation light emitted from the irradiation means is reflected by the water surface and enters the detector. Reflection noise is also caused by the reflection of disturbance light on the water surface. In the case of a float type fluorescence detection device, this noise is generated by providing a cover that blocks sunlight that becomes disturbance light between the device and the water surface. Can be prevented.

  On the other hand, when the amount of light or the water surface fluctuates, the reflection noise from the water surface becomes larger noise with respect to the detected value and has an adverse effect. And when the noise is large in this way, if the amount of fluorescence is small, a small signal is buried in the noise, making it difficult to detect substances such as oil. In order to reduce the reflection noise of the excitation light as described above, it is common to provide an excitation filter in the irradiating means and a fluorescent filter in the detection means. This excitation filter is an optical element for extracting light necessary for excitation of the fluorescent substance from the light source, transmits only excitation light of a specific wavelength, and cuts light of other wavelengths. The fluorescence filter is an optical element for efficiently transmitting fluorescence emitted from the detection target substance, and cuts unnecessary excitation light and disturbance light.

By applying the optical element as described above, it is possible to reduce many portions of reflection noise from the water surface of the excitation light. However, there is a limit to the capability of such an optical element, and a sufficient effect cannot be obtained depending on the detection target substance.
On the other hand, reflection noise from the water is generated when ambient light such as sunlight is reflected on the bottom of a river or a pit and enters the detector.

  Regarding such reflection noise from the water, the above-mentioned patent document 2 proposes a countermeasure. That is, Patent Document 2 discloses that a disturbance light preventing body is provided below the water surface. This disturbance light preventing body is effective as a means for physically suppressing disturbance light. However, there is a problem that in the wastewater containing the suspended matter at a high density such as the factory wastewater, these suspended matter accumulates on the surface of the disturbance light preventing body in a short period of time. And the suspended | floating matter deposited in this way may lead to making a disturbance light prevention body heavy and breaking a weight balance. In such a case, the draft of the fluorescence detection device may change or the levitation posture may be inclined, and the detection function as specified may be impaired.

JP 2003-149134 A JP 2004-028814 A

  An object of the present invention is to provide a fluorescence detection apparatus that sufficiently suppresses noise caused by reflected light or disturbance light mixed at the time of detection and stably obtains a highly accurate detection output.

In order to achieve the above object, the following technologies are proposed.
(1) A fluorescence detection apparatus for detecting a target substance that emits fluorescence when irradiated with excitation light,
A float unit that is combined with a structural member constituting the apparatus main body unit to obtain a buoyancy at which the level position of the apparatus main body unit with respect to the liquid level is within a predetermined range;
An excitation light irradiation unit provided in the apparatus main body so as to irradiate excitation light;
A light detection unit provided in the apparatus main body so as to detect a light reception level of the fluorescence of the target substance by the excitation light irradiated from the excitation light irradiation unit, the excitation light irradiation unit The irradiation optical axis at the time of irradiation is arranged so as to make an inclination of a predetermined first angle in the in-plane rotation direction related to the irradiation optical axis and the vertical line with respect to the vertical line,
The light detection unit is arranged so that the light receiving optical axis is inclined at a predetermined second angle in the same rotational direction as the first angle in a plane related to the light receiving optical axis and the vertical line with respect to the vertical line. The fluorescence detection apparatus characterized by the above-mentioned.

  In the fluorescence detection apparatus according to (1) above, the apparatus main body can float on the liquid by the float part. Therefore, the distance between the apparatus main body and the liquid surface does not depend on the fluctuation of the liquid surface itself, and the target substance This is advantageous for stable detection. Further, the excitation light irradiating unit is configured such that the irradiation optical axis when irradiating the excitation light is inclined at a predetermined first angle in the in-plane rotation direction related to the irradiation optical axis and the vertical line with respect to the vertical line. The light detection unit has a predetermined second angle of inclination in the same rotational direction as the first angle in a plane related to the light receiving optical axis and the vertical line with respect to the vertical line. As a result, the overlap between the excitation light irradiation region from the excitation light irradiation unit and the light receiving field region in the light receiving unit of the light detection unit is relatively large, and the light detection is performed. The detection output level from the unit is relatively higher than that in the case where it is not in the above arrangement, and the detection of the target substance is less affected by disturbance.

(2) The fluorescence detection device according to (1), wherein the excitation light irradiation unit and the light detection unit are arranged so that the first angle and the second angle are different.
In the fluorescence detection device of (2) above, in particular, in the fluorescence detection device of (1), the excitation light irradiation unit and the light detection unit are arranged so that the first angle and the second angle are different. As a result, it becomes difficult for the reflected light that becomes disturbance light to enter the light detection unit, and the influence of the disturbance light is further reduced.

(3) A pre-irradiation data acquisition / holding unit that obtains and holds first detection data from the light detection unit at a first first time point before irradiation time when the excitation light irradiation unit irradiates excitation light, and the irradiation time point. And an irradiation data acquisition / holding unit that obtains and holds second detection data from the light detection unit at the second most recent time point. The fluorescence detection apparatus according to claim 1 or 2.

  In the fluorescence detection device of (3) above, the excitation light is emitted from the excitation light irradiation unit based on data acquired and held by the detection data acquisition unit, particularly in the fluorescence detection device of (1) or (2). A process of subtracting the first detection data obtained from the light detection unit at the first time point immediately before the irradiation time point from the second detection data obtained from the light detection unit at the second time point immediately after the irradiation time point. Can be performed later. For this reason, it becomes possible to obtain detection data in which the influence of disturbance light including reflection noise from the liquid is reduced without providing a disturbance light prevention body or the like below the liquid surface.

(4) The detection data acquisition unit includes the first detection data stored in the pre-irradiation data acquisition holding unit and the data acquisition unit during irradiation stored in an external detection data determination unit that determines the presence or absence of a detection target substance. The fluorescence detection device according to (3), further including a communication circuit unit that transmits the second detection data held in step (1).
In the fluorescence detection device of (4) above, the first detection data and the second detection data are compared with the external detection data determination unit for determining the presence or absence of the detection target substance, particularly in the fluorescence detection device of (3). Can be supplied through the communication circuit section.

(5) Based on detection difference data obtained by subtracting the first detection data held in the pre-irradiation data acquisition holding unit from the second detection data held in the irradiation data acquisition holding unit The fluorescence detection apparatus according to (3), further comprising a detection data determination unit that determines the presence or absence of the.
In the fluorescence detection device of (5), particularly in the fluorescence detection device of (3), the detection data determination unit obtains the pre-irradiation data from the second detection data held by the irradiation time data acquisition holding unit. The presence / absence of the detection target substance can be determined based on the detection difference data obtained by subtracting the first detection data held by the holding unit. For this reason, the determination with reduced influence of disturbance light becomes possible.

(6) A fluorescence detection device that detects a target substance that emits fluorescence when irradiated with excitation light existing in a liquid surface or liquid of a transparent liquid,
A float unit coupled with a structural member constituting the apparatus main body to obtain a buoyancy at which the level position of the apparatus main body relative to the liquid level is within a predetermined range;
An excitation light irradiation unit provided in the apparatus main body so as to irradiate excitation light;
A light detection unit provided in the apparatus main body so as to detect a received light level of fluorescence of the target substance by the excitation light irradiated from the excitation light irradiation unit;
A detection data acquisition unit for acquiring detection data from the light detection unit,
The detection data acquisition unit
A pre-irradiation data acquisition / holding unit that obtains and holds first detection data from the light detection unit at a first time point immediately before the irradiation time point at which the excitation light is irradiated from the excitation light irradiation unit; A data acquisition and holding unit at the time of obtaining and holding second detection data from the light detection unit at the second time point,
Based on detection difference data obtained by subtracting the first detection data held in the pre-irradiation data acquisition holding unit from the second detection data held in the irradiation time data acquisition holding unit, the presence or absence of a detection target substance is determined. A fluorescence detection apparatus further comprising a detection data determination unit for determining.

  In the fluorescence detection device according to (6) above, since the apparatus main body can float on the liquid by the float part, the distance between the apparatus main body and the liquid surface does not depend on the fluctuation of the liquid surface itself, and the target substance This is advantageous for stable detection. Furthermore, based on the data acquired and held by the detection data acquisition unit, the second detection data obtained from the light detection unit at the second time point immediately after the irradiation time point when the excitation light irradiation unit irradiates the excitation light. Thus, a process of subtracting the first detection data obtained from the light detection unit at the first time point immediately before the irradiation time point can be performed at a later stage. For this reason, it becomes possible to obtain detection data in which the influence of disturbance light including reflection noise from the liquid is reduced without providing a disturbance light prevention body or the like below the liquid surface.

  ADVANTAGE OF THE INVENTION According to this invention, the fluorescence detection apparatus which fully suppressed the noise by the reflected light and disturbance light mixed at the time of detection, and was able to obtain a highly accurate detection output stably is realizable.

It is a figure showing the fluorescence detection apparatus as embodiment of this invention. It is a figure for demonstrating selection of the installation angle of the excitation light irradiation part and light detection part in the fluorescence detection apparatus of FIG. It is a figure for demonstrating the effect | action by selection of the installation angle in FIG. It is a functional block diagram showing the detection data processing system in the fluorescence detection apparatus of FIG. FIG. 5 is a timing chart showing operation timing in each unit of FIG. 4. FIG. 5 is a functional block that more specifically represents the configuration of a detection data acquisition unit mounted on the fluorescence detection apparatus main body of FIG. 1 in the detection data processing system of FIG. 4. It is a figure showing the characteristic of the data detection in the detection data acquisition part of FIG. 4 and FIG. It is a figure showing the characteristic of disturbance light suppression in the fluorescence detection apparatus as an embodiment of the present invention.

Hereinafter, the present invention will be clarified by describing embodiments of the present invention in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a diagram showing a fluorescence detection apparatus as a first embodiment of the present invention.
In FIG. 1, a fluorescence detection apparatus 100 is a detection target substance that emits fluorescence FL when irradiated with excitation light EL that is present on the water surface 11 to water 12 of drainage or other water 10 that is a transparent liquid including the case of being translucent. 21 (thing which exists in the water surface 11 thru | or its vicinity) and the detection target 22 (thing which exists in the underwater 12) are detected.

  A float member 120 is provided which is coupled to the structural member 111 constituting the apparatus main body 110 of the fluorescence detection apparatus 100 and obtains a buoyancy at which the level position of the apparatus main body 110 with respect to the water surface 11 is within a predetermined range. In the illustrated example, the float unit 120 is configured by a substantially annular member that surrounds the outer periphery of a region in which the substantially cylindrical casing 112 of the apparatus main body 110 is projected downward (water surface).

  The apparatus main body 110 has a predetermined first angle with respect to a vertical line at the intersection of the liquid surface (water surface) with the optical axis when the irradiation light axis in the casing 112 is irradiated with excitation light. An excitation light irradiation unit 130 is provided so as to form θ1. That is, the excitation light irradiating unit 130 is inclined at a predetermined first angle θ1 in the in-plane rotation direction of the irradiation optical axis when irradiating the excitation light with respect to the vertical line with respect to the irradiation optical axis and the vertical line. It is arranged to make.

Further, in the apparatus main body 110, the light receiving optical axis in the casing 112 has the same direction as the first angle θ1 described above with respect to the vertical line at the intersection with the optical axis on the liquid surface (water surface). The light detection unit 140 is provided so as to form a predetermined second angle θ2 that is an angle between the first angle θ1 and a predetermined second angle θ2 that is different from the first angle θ1. That is, the light detection unit 140 is inclined with a predetermined second angle θ2 in the same rotational direction as the first angle θ1 within the plane of the light receiving optical axis and the vertical line with respect to the vertical line. It is arranged to make.
Further, a detection data acquisition unit 150 (to be described later) is mounted in the housing unit 112 of the apparatus main body 110.

FIG. 2 is a diagram for explaining selection of the installation angle between the excitation light irradiation unit 130 and the light detection unit 140 in the fluorescence detection apparatus 100 of FIG.
FIG. 3 is a diagram for explaining the effect of selection of the installation angle in FIG. 2, and the irradiation area on the water surface of the excitation light by the excitation light irradiation section and the detection area on the water surface for the fluorescence by the light detection section; Represents the degree of overlap. In addition, the solid arrow in FIG. 2 represents the reflected light on the water surface.

  FIG. 2A shows the installation angle between the excitation light irradiation unit and the light detection unit in the conventional fluorescence detection apparatus, and FIG. 2B shows a little relative to the installation angle of FIG. The installation angle in the case where excellent detection characteristics can be obtained is shown. FIG. 2C shows an installation angle in the case where even better detection characteristics can be obtained, relative to the installation angle of FIG. Represents. On the other hand, FIG. 2D shows an example in which the detection characteristics are inferior to any of the above examples.

  In the example of FIG. 2A, the irradiation optical axis when the excitation light irradiation unit 130 irradiates the excitation light is parallel to the vertical line at the intersection with the optical axis on the liquid surface (water surface) (with the irradiation optical axis). The angle formed with the vertical line is 0), and the light receiving optical axis when the fluorescence is detected by the light detection unit 140 is parallel to the vertical line (the angle formed between the light receiving optical axis and the vertical line is 0). ). In this case, as shown in FIG. 3A, the region SA1 where the irradiation region EA1 on the water surface of the excitation light by the excitation light irradiation unit overlaps the detection region FA1 on the water surface with respect to the fluorescence by the light detection unit is relatively It is narrow and the influence of external light that is a disturbance on the fluorescence that is the original detection target in the light detection unit 140 is large. The hatched region UWa in FIG. 2A is an excitation light irradiation region (a three-dimensional virtual region in the liquid) from the excitation light irradiation unit and a light receiving field region in the light receiving unit of the light detection unit. This is a region of overlap with (three-dimensional other virtual region in liquid) in water. In the example of FIG. 2A, this region UWa is also relatively narrow, which is not very advantageous for detecting a detection target substance in water with high sensitivity.

  In the example of FIG. 2B, the irradiation optical axis when the excitation light irradiation unit 130 irradiates the excitation light forms a certain angle θ11 with respect to the vertical line at the intersection of the liquid surface (water surface) with the optical axis. In addition, the light receiving optical axis at the time of detecting the fluorescence by the light detection unit 140 forms the same angle θ11 with respect to the vertical line. That is, the irradiation optical axis and the light receiving optical axis are parallel. Also in this case, as shown in FIG. 3A, the region SA1 where the irradiation region EA1 on the water surface of the excitation light by the excitation light irradiation unit overlaps the detection region FA1 on the water surface with respect to the fluorescence by the light detection unit is relatively It is narrow and disadvantageous for detecting the detection target substance on the water surface with high sensitivity. However, in the case of FIG. 2B, the ratio of incident light reflected from the water surface to the light detection unit is small, which is advantageous in that noise components caused by the reflected light are reduced. . And since this point prevails, it is comparatively advantageous to take the arrangement of FIG. On the other hand, the hatched region UWb in FIG. 2B is an overlapping region in water between the excitation light irradiation region from the excitation light irradiation unit and the light receiving field region in the light receiving unit of the light detection unit. In the example of FIG. 2 (a), this region UWb is also relatively narrow, and in order to detect a detection target substance in water with high sensitivity, in comparison with the example of FIG. Is disadvantageous.

  In the example of FIG. 2C, the irradiation optical axis when irradiating the excitation light by the excitation light irradiation unit 130 is different from the optical axis with respect to the vertical line at the intersection with the optical axis on the liquid surface (water surface). A predetermined first angle θ21 is formed in the in-plane rotation direction with respect to the vertical line. Further, the light receiving optical axis when the fluorescence is detected by the light detection unit 140 is set to the same rotational direction as the first angle θ21 within the plane related to the light receiving optical axis and the vertical line with respect to the vertical line. The predetermined second angle θ22 is different from the first angle θ21. In this case, as shown in FIG. 3B, the region SA2 where the irradiation region EA2 on the water surface of the excitation light by the excitation light irradiation unit overlaps the detection region FA2 on the water surface with respect to the fluorescence by the light detection unit is relatively It becomes wide and is advantageous for detecting the detection target substance on the water surface with high sensitivity. Further, in the case of FIG. 2C, the inclination of the irradiation optical axis and the inclination of the light receiving optical axis are set so that the reflected light from the water surface of the irradiation light does not enter the light detection unit. The reflected light on the water surface hardly enters the light detection unit 140, and therefore, it is extremely advantageous in that the noise component caused by the reflected light on the water surface is sufficiently reduced. Furthermore, in the example of FIG. 2C, the hatched region UWc is an area in water between the excitation light irradiation region UW1 from the excitation light irradiation unit and the light receiving field region UW2 in the light receiving unit of the light detection unit. It is an overlapping area. In the example of FIG. 2C, the first angle θ21 and the second angle θ22 are selected so that the region UWc becomes relatively large. For this reason, it is extremely advantageous to detect a detection target substance in water with high sensitivity.

  On the other hand, in the example of FIG. 2D, the irradiation optical axis when the excitation light irradiation unit 130 irradiates the excitation light is perpendicular to the vertical line at the intersection of the liquid surface (water surface) with the optical axis. A constant angle θ31 is formed in the in-plane rotation direction related to the optical axis and the vertical line. Further, the light receiving optical axis when detecting the fluorescence by the light detecting unit 140 is inclined with respect to the corresponding vertical line in a direction opposite to the above angle in a plane related to the light receiving optical axis and the vertical line, etc. The quantity angle is -θ31. That is, it is an object regarding the irradiation optical axis, the light receiving optical axis, and the vertical line. In this case, as shown in FIG. 3B, a region SA1 where the irradiation region EA1 on the water surface of the excitation light by the excitation light irradiation unit overlaps the detection region FA1 on the water surface with respect to the fluorescence by the light detection unit is relatively It should be wide, and it should be advantageous to detect the detection target substance on the water surface with high sensitivity. However, in this case, the ratio of the incident light reflected from the water surface to the light detection unit is the largest in the above example, so that the noise component caused by the reflected light becomes extremely large. It is very disadvantageous and this disadvantage is better. On the other hand, the hatched region UWd in FIG. 2D is an overlapping region in water between the excitation light irradiation region from the excitation light irradiation unit and the light receiving field region in the light receiving unit of the light detection unit. In the example of FIG. 2D, this region UWd is relatively narrow, which is disadvantageous for detecting a detection target substance in water with high sensitivity.

In the above, regarding the selection of the installation angle between the excitation light irradiation unit 130 and the light detection unit 140, the advantages and disadvantages related to the fluorescence detection characteristics have been described with reference to FIGS.
Next, among the installation modes shown in FIG. 2, FIG. 2 (a), which is a conventional mode, FIG. 2 (c), which is the most excellent mode corresponding to the embodiment of the present invention, and The following table shows the results of experiments conducted with specific simulated conditions set for each example of FIG. 2D, which is a poor mode. The value of “sensitivity S / N” in this table is an index representing the superiority or inferiority of the detection characteristics as a whole. As will be understood at a glance, the overwhelming superiority of FIG. 2C corresponding to the embodiment of the present invention is demonstrated.

  In the above table, the “reflection level” is a transparent glass plate in place of the static water surface in order to set conditions that are not affected by the ripples of the water surface and reflection from the bottom of the water tank (water bottom). The reflection from this glass plate was measured. The “fluorescence level” was determined by placing a petri dish containing oil at the position of the glass plate and measuring the fluorescence of the oil. The petri dish has a black matte coating for antireflection.

FIG. 4 is a functional block diagram showing a detection data processing system in the fluorescence detection apparatus of FIG.
FIG. 5 is a timing chart showing the operation timing in each part of FIG.
In FIG. 4, a light emission trigger signal generation unit 410 that supplies a light emission trigger signal S00 for controlling the timing of excitation light irradiation to the excitation light irradiation unit 130 is provided. FIG. 5B shows the timing (time point t0) at which the light emission trigger signal S00 is generated.

  The light emission trigger signal generation unit 410 also supplies a first detection timing signal S10 that defines the timing of data detection from the light detection unit 140 to the pre-irradiation data acquisition and holding unit 420. In other words, the pre-irradiation data acquisition and holding unit 420 is based on the first detection timing signal S10, and the first detection time signal T10 is emitted from the light detection unit 140 at the first time t1 immediately before the irradiation time t0 when the excitation light irradiation unit 130 irradiates excitation light. 1 detection data is obtained and held. FIG. 5A shows the timing at which the first detection timing signal S10 is generated (time t1), and FIG. 5D shows the timing at which the first detection data is obtained and held.

  The detection data from the light detection unit 140 is also supplied to the irradiation data acquisition / holding unit 430, where it is acquired / held. That is, the data acquisition / holding unit 430 at the time of irradiation is based on the second detection timing signal S20 supplied from the sample hold control unit 440 at a timing synchronized with the excitation light irradiation in the excitation light irradiation unit 130. The fluorescence detection output detected at 140 is acquired and held (sample hold). FIG. 5C shows the timing (time t2) at which the above-described second detection timing signal S20 is emitted, and FIG. 5E shows the timing of fluorescence emission generated in response to the above-described excitation light irradiation. The timing at which the fluorescence detection output is acquired and held (sample hold) is shown in f).

A series of operations from the irradiation of the excitation light described with reference to FIG. 5 to the detection of the fluorescence by the excitation light is repeatedly and continuously executed at a constant period, as is apparent from the drawing.
In the present embodiment, the detection data acquisition unit 450 includes the light emission trigger signal generation unit 410, the pre-irradiation data acquisition / holding unit 420, the irradiation time data acquisition / holding unit 430, and the sample hold control unit 440. ing. The detection data acquisition unit 450 corresponds to the detection data acquisition unit 150 in FIG.

In the present embodiment, the detection data acquisition unit 450 includes the first detection data D held by the pre-irradiation data acquisition holding unit 420 and the second detection data L held by the irradiation time data acquisition holding unit 430. Is transmitted from the communication circuit unit, which will be described later, through the cable 460 to the external detection data determination unit 470 that determines the presence or absence of the detection target substance.
The detection data determination unit 470 performs a calculation of subtracting the first detection data D from the second detection data L described above to obtain detection difference data L-D, and a calculation result by the subtraction processing unit 471 A determination processing unit 472 that determines the presence or absence of a detection target substance by comparing the value with a predetermined threshold, and an alarm generation that generates an alarm in response to the determination processing unit 472 issuing an output indicating that the detection target substance is present A portion 473 is included.

Since the subtraction processing as described above is performed in the subtraction processing unit 471, the influence of disturbance light including reflection noise from the liquid is reduced without providing the disturbance light prevention body or the like as in the prior art described above. Detected data can be obtained.
As is clear from the comparison between FIG. 5A and FIG. 5C, and hence the comparison between FIG. 5D and FIG. 5F, in the present embodiment, detection difference data L-D is obtained. A time difference T related to sampling is generated between the timing of acquiring the first detection data D provided for and the timing of acquiring the second detection data L. This time difference T is a value that affects the ability to remove the influence of disturbance light in the apparatus of the present embodiment, and will be described in detail later with reference to the drawings.

6 is a functional block that more specifically represents the configuration of the detection data acquisition unit mounted on the fluorescence detection apparatus main body of FIG. 1 in the detection data processing system of FIG.
The function of the detection data acquisition unit 600 shown in FIG. 6 corresponds to the function of the detection data acquisition unit 450 in FIG.
In FIG. 6, the excitation light irradiation unit 130 is provided with a light emission monitor unit 131 that monitors the irradiation intensity of the excitation light, and the irradiation intensity of the excitation light from the excitation light irradiation unit 130 according to the detection level of the light emission monitor unit 131. Is configured to be closed-loop controlled to maintain an appropriate level.

The excitation light irradiation unit 130 performs the light emission operation upon receiving the supply of irradiation power from the irradiation power supply unit 610. The timing of power supply from the irradiation power supply unit 610 is controlled by a timing signal from the light source drive signal generation unit 611. In the present embodiment, the power of the irradiation power supply unit 610 is supplied from the outside through the power supply conductor 612 in the cable.
On the other hand, the fluorescence detection output detected by the light detection unit 140 is subjected to a predetermined amplification by the amplification unit 621 after the noise component is removed through the filter unit 620 whose pass band is the fluorescence wavelength range, and then the sample. The hold unit 622 acquires and holds the timing described above with reference to FIG.

  Detection data that is an analog signal acquired and held by the sample hold unit 622 is converted into digital data through the AD conversion unit 623. Then, digital data that is an output of the AD conversion unit 623 is supplied to the system controller 630. The system controller 630 is mainly composed of a microprocessor, and comprehensively manages the operation of the entire system of the detection data acquisition unit 600, and performs necessary data processing and exchange of data with the outside.

In the configuration of FIG. 6 described above, the corresponding functions of the light source drive signal generation unit 611 and the system controller 630 correspond to the function of the trigger signal generation unit 410 of FIG. still. In FIG. 4, functional units corresponding to the irradiation power supply unit 610 are not shown.
Further, the corresponding functions of the filter unit 620, the amplification unit 621, the sample hold unit 622, the AD conversion unit 623, and the system controller 630 in FIG. The overall function of the acquisition / holding unit 430 and the sample hold control unit 440 is provided. As a result, as the output of the AD conversion unit 623, digital data SD1 corresponding to the output of the pre-irradiation data acquisition / holding unit 420 in FIG. 4 and digital data SD2 corresponding to the data acquisition / holding unit 430 during irradiation are sequentially output. Is supplied to the system controller 630 and held. That is, the digital data SD1 corresponds to the first detection data D in FIG. 4, and the digital data SD2 corresponds to the second detection data L.

  A communication circuit unit 640 is provided under the control of the system controller 630, and the communication circuit unit 640 conforms to the communication method in which the digital data SD1 and SD2 held in the system controller 630 as described above are applied to data transmission. The signal is converted into a signal format and transmitted to the detection data determination unit 470 (FIG. 4) through the signal conductor 641 in the cable.

FIG. 7 is a diagram illustrating data detection characteristics when fluorescence is detected in the detection data acquisition unit of FIGS. 4 and 6.
FIG. 7 (a) virtually represents the characteristics of fluorescence data detection under conditions that are not affected by ambient light. FIG. 7B shows actual characteristics of fluorescence data detection under the condition of being affected by disturbance light.
In both FIG. 7 (a) and FIG. 7 (b), as shown in the figure, immediately after the excitation light projection time, the fluorescence detection level increases relatively quickly with a constant time constant and reaches a peak. After that, it exhibits the characteristic of descending relatively slowly.

  The hatched portion in FIG. 7B is the fluorescence detection level (first detection data D) immediately before the excitation light projection time described with reference to FIGS. 4 and 5, that is, the detection of disturbance light. Is a level. As shown in the figure, the level of the detection data D also changes with time. In the case of FIG. 7B, the detection data changes from D to D ′ within the time T from the time when the excitation light is projected until the time when the detection level of the fluorescence reaches the peak. This is because when detecting the fluorescence intensity S by subtracting the detection signal data D detected immediately before the excitation light projection time from the detection signal data L detected at the time of excitation light projection, , The difference in the degree of the effect that can remove the error depending on the frequency).

The error that can be removed as described above greatly depends on the frequency that is a characteristic of the temporal transition of the disturbance light intensity. Next, the effect of suppressing the influence of disturbance light in the apparatus according to the present embodiment in consideration of the frequency of disturbance light will be described below.
FIG. 8 is a diagram illustrating disturbance light suppression characteristics in the fluorescence detection apparatus according to the embodiment of the present invention.
FIG. 8 shows a level change for one period assuming that the disturbance light is a triangular wave of a certain frequency. For example, when the disturbance light has a so-called flicker, the flicker is for one period. Responds to changes in levels.
For the triangular wave in FIG. 8, the time (t1) immediately before the excitation light irradiation, which is the acquisition time point of the first detection data D acquired as described above with reference to FIGS. 4 and 5, and the second detection data L Attention is paid to the change in the value of the detection level corresponding to the time difference T (sampling interval) from the fluorescence peak vicinity time (t2) that is the acquisition time.

Here, in the apparatus of the present embodiment, it is assumed that the required specification regarding the characteristic for removing the influence of disturbance light is regulated to be suppressed to 1/10 of the peak value of the disturbance light.
In other words, the state where the required specifications are satisfied means that the change in the level of disturbance light detection corresponding to the sampling interval T is within a range of 1/10 or less of the peak value.
Accordingly, when the disturbance light detection level frequency f is f = 1 / 20T or less, the above-mentioned required specification is satisfied. In a specific example, when T = 10 μsec, the above required specification is satisfied with respect to disturbance light of f = 5 kHz or less.

(Second Embodiment)
The configuration surrounded by the alternate long and two short dashes line in FIG. 4 having both the detection data acquisition unit 450 and the detection data determination unit 470 in FIG. 4 described above is applied to the fluorescence detection apparatus according to the second embodiment of the present invention. Applicable.
However, in the second embodiment, since the detection data acquisition unit 450 and the detection data determination unit 470 are installed relatively close to each other, the cable 460 that connects the two as in the above-described first embodiment. Is not necessary, and a configuration of connecting with ordinary wiring is adopted.
In the second embodiment, since the subtraction processing unit 471 in the detection data determination unit 470 performs the subtraction process as described above, a disturbance light prevention body or the like as described in the related art is provided below the liquid surface. Thus, it is possible to obtain detection data in which the influence of disturbance light including reflection noise from the liquid is reduced.

10 ………………………………… Water (transparent liquid)
11 ………………………………… Water surface (liquid surface)
12 ………………………………… Underwater (in liquid)
21 ... ……………………………… Target substance 22 …………………………………… Target substance 100 ……………………………… Fluorescence detection device 110… …………………………… Device main body 111 ……………………………… Structural member 112 ……………………………… Case 120 ………… …………………… Float unit 130 ……………………………… Excitation light irradiation unit 131 ……………………………… Emission monitor unit 140 ……………… ……………… Light detector 150 ………………………… Detection data acquisition unit 410 ……………………………… Light emission trigger signal generator 420 …………… ………………… Pre-irradiation data acquisition / holding unit 430 ……………………………… Irradiation data acquisition / holding unit 440 ……………………………… Sample hold control unit 450 …………… ……………… Detection data acquisition unit 460 ……………………………… Cable 470 ……………………………… Detection data determination unit 471 …………………… ………… Subtraction processing unit 472 ……………………………… Judgment processing unit 473 ……………………………… Alarm generating unit 600 ………………………… …… Detection data acquisition 610 ……………………………… Irradiation power supply unit 611 ……………………………… Timing is the light source drive signal generation unit 612 ……………… ……………… Power supply conductor 620 ……………………………… Filter 621 ……………………………… Amplifier 622 ……………………… ……… Sample hold unit 623 ……………………………… AD converter 630 ……………………………… System controller 640 ………………… ............ sample-and-hold control unit 440
641 ……………………………… Signal conductor

Claims (6)

A fluorescence detection device that detects a target substance that emits fluorescence when irradiated with excitation light,
A float unit that is combined with a structural member constituting the apparatus main body unit to obtain a buoyancy at which the level position of the apparatus main body unit with respect to the liquid level is within a predetermined range;
An excitation light irradiation unit provided in the apparatus main body so as to irradiate excitation light;
A light detection unit provided in the apparatus main body so as to detect a light reception level of the fluorescence of the target substance by the excitation light irradiated from the excitation light irradiation unit, the excitation light irradiation unit The irradiation optical axis at the time of irradiation is arranged so as to make an inclination of a predetermined first angle in the in-plane rotation direction related to the irradiation optical axis and the vertical line with respect to the vertical line,
The light detection unit is arranged so that the light receiving optical axis is inclined at a predetermined second angle in the same rotational direction as the first angle in a plane related to the light receiving optical axis and the vertical line with respect to the vertical line. The fluorescence detection apparatus characterized by the above-mentioned.   The fluorescence detection apparatus according to claim 1, wherein the excitation light irradiation unit and the light detection unit are arranged such that the first angle and the second angle are different.   A pre-irradiation data acquisition / holding unit that obtains and holds first detection data from the light detection unit at a first time point immediately before the irradiation time point at which the excitation light is irradiated from the excitation light irradiation unit; 2. A detection data acquisition unit configured to include an irradiation data acquisition holding unit that obtains and holds second detection data from the light detection unit at the second time point. Or the fluorescence detection apparatus of 2.   The detection data acquisition unit is held by the first detection data held by the pre-irradiation data acquisition holding unit and the data acquisition unit during irradiation held in an external detection data determination unit that determines the presence or absence of a detection target substance. The fluorescence detection apparatus according to claim 3, further comprising a communication circuit unit that transmits the second detection data.   The detection data acquisition unit is based on detection difference data obtained by subtracting the first detection data held by the pre-irradiation data acquisition holding unit from the second detection data held by the irradiation data acquisition holding unit. The fluorescence detection apparatus according to claim 3, further comprising a detection data determination unit that determines the presence or absence of a detection target substance. A fluorescence detection device that detects a target substance that emits fluorescence when irradiated with excitation light,
A float unit that is combined with a structural member constituting the apparatus main body unit to obtain a buoyancy at which the level position of the apparatus main body unit with respect to the liquid level is within a predetermined range;
An excitation light irradiation unit provided in the apparatus main body so as to irradiate excitation light;
A light detection unit provided in the apparatus main body so as to detect a received light level of fluorescence of the target substance by the excitation light irradiated from the excitation light irradiation unit;
A detection data acquisition unit for acquiring detection data from the light detection unit,
The detection data acquisition unit
A pre-irradiation data acquisition / holding unit that obtains and holds first detection data from the light detection unit at a first time point immediately before the irradiation time point at which the excitation light is irradiated from the excitation light irradiation unit; A data acquisition and holding unit at the time of obtaining and holding second detection data from the light detection unit at the second time point,
Based on detection difference data obtained by subtracting the first detection data held in the pre-irradiation data acquisition holding unit from the second detection data held in the irradiation time data acquisition holding unit, the presence or absence of a detection target substance is determined. A fluorescence detection apparatus further comprising a detection data determination unit for determining.

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