JP4439454B2 - Leak detection device and leak detection method - Google Patents

Description

The present invention relates to a leak detection apparatus and a leak detection method for detecting a leak of a detection target that emits fluorescence when irradiated with a laser beam.

  Generally, oil emits fluorescence when irradiated with ultraviolet rays. For this reason, in the leak detection apparatus using the fluorescence method, the fluorescence emitted by the ultraviolet irradiation is observed to recognize the oil and detect the leak from the object to be inspected.

  Conventionally, as such a leak detection apparatus, a leak location detection apparatus shown in FIG. 4 is known (see, for example, Patent Document 1). In this prior art, a device under test 101 is installed in a dark room 102 shielded from illumination, sunlight, etc., and a pulsed ultraviolet ray is irradiated from an ultraviolet light source 103. Then, since fluorescence is emitted when there is oil leakage, the detector 105 is operated by the delay circuit 104 and the fluorescence is observed after the disappearance of the pulse of ultraviolet rays. Since the detector 105 is operated after the ultraviolet pulse disappears, the ultraviolet light from the ultraviolet light source 103 does not become noise light, and fluorescence can be observed at a high SN. When the detector 105 is a camera, the observed fluorescence is displayed as an image on the processing device 106, and oil leakage is detected.

On the other hand, as a technique for observing fluorescence emitted from oil at a high SN, there is known a technique in which a spectroscopic element is attached to the detector 105 and the wavelength of oil fluorescence is selected because the fluorescence emission spectrum is unique to the substance. (For example, refer to Patent Document 2). According to this technique, light emission other than oil can be cut by wavelength, so that oil fluorescence can be observed with high SN.
JP-A-6-18356 Japanese Patent Laid-Open No. 3-77003

  In the above-described conventional leak detection device, when the dark room cannot be set outside the building and the illumination or sunlight cannot be shielded, the illumination and sunlight become noise light, so that the SN of fluorescence decreases. There was a problem that it was difficult to detect leakage.

  In addition, the emission spectrum of fluorescence from oil is often included in the spectrum of illumination, sunlight, and the like. For this reason, in a spectroscopic element, illumination, sunlight, etc., and oil fluorescence cannot be separated by wavelength. Therefore, when lighting, sunlight, etc. cannot be shielded outside the building, even if a spectroscopic element is attached to the detector, the illumination, sunlight, etc. become noise light, and the SN of fluorescence is reduced to detect leakage. There was a problem that became difficult.

The present invention has been made in order to solve the above-described problems, and enhances the fluorescence emitted from a detection target such as oil even in an environment of noise light where lighting, sunlight, etc. cannot be shielded outside the building. It is an object of the present invention to provide a leak detection device and a leak detection method that can detect leaks from an object to be inspected by observation with an SN.

In order to achieve the above object, according to the present invention, there is provided a leakage detection device for detecting leakage of a detection target that emits fluorescence by irradiation of laser light, and irradiates a plurality of polarized laser beams having different irradiation wavelengths to an object to be inspected. Irradiation means, polarization selection means for selecting and observing the polarization fluorescence of polarized light with respect to the polarized fluorescence of each irradiation wavelength emitted by irradiation of polarized laser light by the irradiation means, and a wavelength at which the intensity of polarized fluorescence of each component increases A spectroscopic means for selecting and observing the polarized fluorescence of each component by selecting a band; and a light detecting means for detecting the polarized fluorescence of which polarization and wavelength are selected, the irradiating means comprising a laser light source, a polarization state the holding and an optical fiber for transmitting a polarized laser beam, characterized in that it is configured the polarization direction of the laser light variable by rotating twisting outlet side of the polarized laser beam of the optical fiber To provide a leak detection system to be.
The present invention is also a leakage detection method for detecting leakage of a detection target that emits fluorescence by laser light irradiation, and transmits a plurality of polarized laser beams having different irradiation wavelengths while maintaining the polarization state by an optical fiber. A polarized laser beam transmission step, a polarization direction changing step for changing the polarization direction of the polarized laser beam by twisting the exit side of the polarized laser beam of the optical fiber, and an irradiating step for irradiating the object to be inspected with the polarized laser beam; , Select the polarization selection step to select and observe the polarization of polarized fluorescence for the polarized fluorescence of each irradiation wavelength emitted by the irradiation of polarized laser light by this irradiation means, and select the wavelength band where the intensity of the polarized fluorescence of each component increases A spectroscopic step for integrating and observing the polarized fluorescence of each component, and a light detecting step for detecting the polarized fluorescence of which polarization and wavelength are selected. It provides a leak detection method according to claim.

  According to the present invention, polarized fluorescence can be observed at a high SN, and leakage of a detection target can be detected from an object to be inspected in an environment of noise light.

Hereinafter, embodiments of a leak detection apparatus and a leak detection method according to the present invention will be described with reference to the drawings.

[First Embodiment (FIG. 1)]
FIG. 1 is a configuration diagram showing a first embodiment of a leak detection apparatus according to the present invention. In FIG. 1, an object 1 to be inspected by the leakage detection apparatus of the present embodiment is an object installed in an environment of noise light that cannot be shielded from illumination or sunlight outside a building or the like, such as equipment or components, A structure, or a vehicle, an aircraft, a ship, or the like. The detection target 4 leaking from the test object 1 is a substance such as oil that emits fluorescence when irradiated with laser light. Fluorescence is one type of luminescence emitted by a molecule that has absorbed light and is in an electronically excited state in the process of returning to the ground state. It is known that when a molecule absorbs linearly polarized light, linearly polarized polarized fluorescence is emitted.

In the present embodiment, an irradiating means 2a for irradiating the inspected object 1 with linearly polarized laser light is provided. The irradiating means 2a is constituted by a linearly polarized laser light source that irradiates laser light having a wavelength that is strongly absorbed by the detection target 4. When the detection target 4 is oil, the strongly absorbing wavelength is often in the ultraviolet region, but when it is unknown, the absorption spectrum is obtained by actually measuring the absorption spectrum. When there are other substances that absorb light and emit light, the wavelength of the laser light is appropriately selected according to the absorption spectrum of these substances. For substances with unknown absorption spectra, measure them. Note that the laser light can be oscillated continuously or pulsed. In this embodiment, an excimer laser such as an Ar laser, an N ₂ laser, ArF, KrF, or XeCl is used as the irradiation unit 2 in this embodiment.

  The irradiation means 2a is provided with a polarization direction control means 3 for controlling the polarization direction of the laser light having linear polarization characteristics. This polarization direction control means 3 is constituted by a wave plate capable of changing the direction of linearly polarized light. The direction of linearly polarized light can be changed by rotating the crystal axis of the wave plate. As such a polarization direction control means 3, in this embodiment, for example, a half-wave plate, a plurality of quarter-wave plates, or a higher-order wave plate combining a plurality, an adjustable Babinet wave plate, a Faraday A polarization rotator or the like by an element is applied.

  In the present embodiment, the polarization selection means 5 for selecting and observing the polarization of the polarized fluorescence with respect to the polarized fluorescence of the detection target 4 emitted by irradiation of the linearly polarized laser light when there is leakage in the inspection object 1. I have. The polarization selection means 5 is composed of a polarizer that transmits only light in the polarization direction of the principal axis direction. Light having a polarization direction orthogonal to the main axis is not transmitted. By rotating the main axis, the transmitted polarization direction can be changed. For example, a polarizing prism such as a Gram-Thomson prism, a polarizing plate, a Pockels element, a Kerr element, or the like is applied as the polarization selection unit 5.

  Further, a spectroscopic means 6 for selecting and observing the wavelength of the polarized fluorescence with respect to the polarized fluorescence of which polarization has been selected is provided. The spectroscopic means 6 is composed of a spectroscopic element that selects and selects polarized fluorescence emitted from the detection target 5 by wavelength. The wavelength of the polarized fluorescence is longer than the wavelength of the absorbed light, but when the wavelength is unknown, it is obtained by actually measuring the polarized fluorescence spectrum. Note that the wavelength of the polarized fluorescence has a wavelength broadening, and the wavelength band for spectral separation is appropriately selected according to the emission spectrum of noise light. When the emission spectrum of noise light is unknown, it is measured. As such a spectroscopic means 6, for example, a transmission type or reflection type diffraction grating, a prism, an interference filter, a color glass filter, or the like is applied.

  In the present embodiment, imaging means 7a and 7b are provided for capturing an image of polarized fluorescence whose polarization and wavelength are selected, and imaging and detecting leakage. The imaging means 7a is composed of an imaging element that observes an image. When the polarized fluorescence with the selected polarization and wavelength is weak, the polarized fluorescence is amplified and observed. As such an imaging means 7a, for example, a CCD camera, a CMOS camera or the like is applied. When amplification of polarized fluorescence is necessary, an amplifying mechanism using a microchannel plate or the like is attached to a CCD camera, a CMOS camera, or the like to amplify weak light.

  The image pickup means 7b is constituted by a processing device that takes in the image 8 of polarized fluorescence observed by the image pickup device, and displays and saves the screen.

  Such an imaging unit 7b is configured as a PC or an ITV monitor including a storage device such as a magnetic type or an optical type.

  Next, the operation will be described. As the irradiation wavelength of the irradiation means 2a, a wavelength having a higher absorbance of the detection target 4 than other substances is selected. The linearly polarized laser light emitted from the irradiating means 2 a is diffused and irradiated to the object 1 after the polarization direction is changed by the polarization direction control means 3. When the detection target 4 leaks to the inspection object 1, the irradiated laser beam has a wavelength that is strongly absorbed by the detection target 4 compared to other substances and is linearly polarized light. To linearly polarized polarized light.

  For this polarized fluorescence, the main axis of the polarization selection means 5 is rotated to align the transmission axis with the polarization direction of the polarized fluorescence, and the polarized fluorescence is selected and observed by the polarized light. Thereby, polarized fluorescence can be selected and observed, and noise light other than linearly polarized light polarized in the same direction as the polarization direction of polarized fluorescence can be reduced. Subsequently, with respect to the polarized fluorescence observed by selecting the polarized light, the spectral fluorescence is dispersed by the spectroscopic means 6 and observed. The spectral wavelength band is selected by adjusting or exchanging the spectroscopic means 6 so that the polarized fluorescence has a higher emission intensity than the noise light.

  Thereby, polarized fluorescence can be selected and observed, and noise light other than the same band as the wavelength of polarized fluorescence can be reduced. Then, the polarized fluorescence observed by selecting the polarization and wavelength is amplified as necessary when it is weak, and then observed by the imaging means 7a. The image observed by the imaging means 7a is an image observed by selecting the polarization and wavelength of the polarized fluorescence. Further, since the noise light is reduced, only the polarized fluorescence is an image observed at a high SN. . For this reason, in the imaging means 7b, the polarization fluorescence image 8 which only the detection target 4 emitted in the screen can be obtained, and the leakage of the detection target 4 can be detected.

  According to such a first embodiment, the detection target 4 emits polarized fluorescence from the detection target 4 by irradiating the linearly polarized laser beam having a wavelength having a higher absorbance than other substances. Then, with respect to this polarized fluorescence, the polarized light can be selected and observed by selecting and observing the polarized light with the polarized light selecting means 5, and then selecting and observing with the wavelength by the spectroscopic means 6. Furthermore, noise light can be reduced. As a result, polarized fluorescence can be observed with high SN by the imaging means 7a, and an image 8 of polarized fluorescence emitted only by the detection target 4 can be obtained in the imaging means 7b. 1 to leak of the detection object 4 can be detected.

  Note that there may be a large amount of linearly polarized noise light polarized in the same direction as the polarization direction of the polarized fluorescence, and the SN of the polarized fluorescence image 8 in the imaging means 7b may be low. In this case, the noise light observed in the image pickup means 7b can be reduced by rotating the main axis of the polarization selection means 5 so as to be orthogonal to the polarization direction of the noise light. In this state, linearly polarized laser light is irradiated from the irradiation means 2a, and the polarization direction is changed by rotating the crystal axis of the polarization direction control means 3. As a result, the polarization direction of the polarized fluorescence changes, so that the polarized fluorescence can be selected and observed by polarization by matching the polarization direction of the polarized fluorescence with the main axis of the polarization selection means 5. At this time, the polarization directions of polarized fluorescence and noise light are orthogonal to each other. Thereby, polarized fluorescence can be selected and observed, and noise light can be reduced because its polarization direction is orthogonal to the main axis of the polarization selection means 5. After that, by selecting and observing the wavelength of the polarized fluorescence, it is possible to obtain polarized fluorescence with high SN and further reduced noise light. As a result, the imaging unit 7b can obtain an image 8 of polarized fluorescence emitted only by the detection target 4 in the screen, and can detect leakage of the detection target 4.

  Therefore, by rotating the polarization direction of the polarized fluorescence by the polarization direction control means 3 so as to be orthogonal to the polarization direction of the linearly polarized noise light, the polarized fluorescence can be selected and observed by the polarization selection means 5. Linearly polarized noise light can be reduced. As a result, polarized fluorescence can be observed with high SN by the imaging means 7a, and an image 8 of polarized fluorescence emitted only by the detection target 4 can be obtained in the imaging means 7b. 1 to leak of the detection object 4 can be detected.

[Second Embodiment (FIG. 2)]
FIG. 2 is a block diagram showing a second embodiment of the leak detection apparatus according to the present invention. In addition, the same code | symbol as FIG. 1 is attached | subjected to the component same as 1st Embodiment, and the overlapping description is abbreviate | omitted.

  In the present embodiment, the irradiation means 2a for irradiating the inspection object 1 with linearly polarized laser light, the transmission means 9a for transmitting the linearly polarized laser light through an optical fiber while maintaining the polarization state, and the inspection object 1 Polarization selection means 5 for selecting and observing the polarized fluorescence of the polarized fluorescence with respect to the polarized fluorescence of the detection target 4 emitted by irradiation of the linearly polarized laser light in the presence of leakage, and further for the polarized fluorescence with the polarized light selected Spectroscopic means 6 for selecting and observing the wavelength of polarized fluorescence, and light detecting means 10a and 10b for detecting the presence or absence of leakage by measuring the light intensity of polarized fluorescence whose polarization and wavelength are selected.

  The transmission means 9a is composed of an optical fiber that transmits laser light while maintaining the state of linearly polarized light. Specifically, a polarization maintaining fiber, a photonic crystal fiber, or the like is applied as the transmission unit 9a.

  The light detection means 10a is composed of a light detector that measures light intensity. As such a light detection means 10a, a photodiode, a PIN photodiode, a photoelectric tube or the like is applied. In addition, when the polarized fluorescence whose polarization and wavelength are selected is weak, it is desirable to use a highly sensitive photodetector such as a photomultiplier tube or an avalanche photodiode.

  The light detection means 10b is constituted by a processing device that takes in the polarized fluorescence signal 11 measured by the light detector, and displays and saves the screen. Such an imaging means 7b is constituted by, for example, a PC or an oscilloscope provided with a storage device such as a magnetic type or an optical type.

  Next, the operation will be described. Depending on the inspected object 1, it may be necessary to detect only the presence or absence of leakage of the detection target 4. In this case, the laser light emitted from the irradiation means 2a is transmitted to the vicinity of the object 1 by the transmission means 9a, diffused, and irradiated to the object 1 to be inspected. Then, the polarized fluorescence of the detection target 4 observed by selecting the polarized light and wavelength is measured by the polarized light selecting means 5 and the spectroscopic means 6 by the light detecting means 10a corresponding to the light intensity of the polarized fluorescence.

  The light intensity measured by the light detection means 10a is the light intensity of the polarized fluorescence measured by selecting the polarization and wavelength of the polarized fluorescence. Further, since the noise light is reduced, only the polarized fluorescence has a high SN. It is measured. For this reason, in the light detection means 10b, the signal level is increased by the polarized fluorescence and the polarized fluorescence signal 11 of the detection target 4 can be obtained, and the presence or absence of leakage of the detection target 4 can be detected.

  In addition, spectrum measurement is possible by narrowing the wavelength band of the spectroscopic means 6 and scanning the spectral wavelength. When the spectroscopic means 6 is a prism or a diffraction grating, spectrum measurement can be performed even if the light detection means 10b are arranged in an array. When the polarized fluorescence spectrum of the detection target 4 is characteristic, it is possible to determine the type of the detection target 4 by comparing the spectra measured before and after the leakage of the detection target 4.

  Therefore, by measuring the light intensity of the polarized fluorescent light, which is measured by selecting the polarization and wavelength of the polarized fluorescent light and further reducing the noise light, the light detecting means 10b is in an environment of noise light. However, the presence or absence of leakage of the detection target 4 can be detected based on the signal level.

  Further, by performing spectrum measurement with the spectroscopic means 6, when the polarized fluorescence spectrum of the detection target 4 is characteristic, the spectrum measured before and after the leakage of the detection target 4 is compared to determine the type of the detection target 4. Is also possible.

  Note that linearly polarized noise light that is polarized in the same direction as the polarization direction of the polarized fluorescence is large, the level of the fluorescence due to the polarized fluorescence is small in the light detection means 10b, and the SN of the polarized fluorescence signal 11 may be low. In this case, the main axis of the polarization selection unit 5 is rotated to be orthogonal to the polarization direction of the noise light, thereby reducing the noise light observed in the light detection unit 10b. In this state, the linearly polarized laser beam is irradiated from the irradiation unit 2a, and the exit side of the transmission unit 9a to which the laser beam is output is twisted and rotated. In this case, since the polarization state is maintained and transmitted to the vicinity of the device under test 1 in the transmission means 9a, the polarization direction of the laser light can be changed by twisting and rotating the exit side. Then, by aligning the polarization direction of the polarized fluorescence that changes in accordance with this with the principal axis of the polarization selection means 5, the polarized fluorescence can be selected and observed by polarization. Furthermore, linearly polarized noise light is reduced because its polarization direction is orthogonal to the principal axis of the polarization selection means 5. After that, by selecting and observing the wavelength of the polarized fluorescence, it is possible to obtain polarized fluorescence with high SN and further reduced noise light. As a result, in the light detection means 10b, the signal level is increased by the polarized fluorescence and the polarization fluorescence signal 11 of the detection target 4 can be obtained, and the presence or absence of leakage of the detection target 4 can be detected.

  Therefore, by rotating the polarization direction of the polarized fluorescence by the transmission unit 9a and making it orthogonal to the polarization direction of the linearly polarized noise light, the polarized fluorescence can be selected and observed by the polarization selecting unit 5, and further, the linearly polarized noise light can be observed. Can be reduced. As a result, polarized fluorescence can be observed with high SN by the light detection means 10a, and the light detection means 10b can detect the presence or absence of leakage of the detection target 4 based on the signal level even in the environment of noise light. .

  Further, the laser beam can be easily guided from the irradiation unit 2a to the vicinity of the object 1 to be inspected by the transmission unit 9a.

[Third Embodiment (FIG. 3)]
FIG. 3 is a block diagram showing a third embodiment of the leak detection apparatus according to the present invention. In addition, the same code | symbol as FIG.1 and FIG.2 is attached | subjected to the component same as 1st Embodiment and 2nd Embodiment, and the overlapping description is abbreviate | omitted.

  In the leakage detection apparatus of the present embodiment, when a plurality of components that emit polarized fluorescence are included in the detection target 4, the irradiation means 2a and 2b having different irradiation wavelengths and the polarization state are used so that the polarized fluorescence is emitted from the plurality of components. And transmission means 9a, 9b for transmitting linearly polarized laser light through an optical fiber, and the polarized fluorescence of the detection target 4 emitted by irradiation of linearly polarized laser light when there is leakage in the inspection object 1 And polarization selection means 5 for selecting and observing the polarization of the polarized fluorescence.

  Further, the spectroscopic means 6 for selecting and observing the wavelength of the polarized fluorescence with respect to the polarized fluorescence with the polarized light selected, and detecting the presence or absence of leakage by measuring the light intensity of the polarized fluorescence with the polarized light and the wavelength selected. Visible images in the case of the light detection means 10a, 10b, the traveling scanning means 12a, 12b, 12c for inspecting the plurality of inspected objects 1, and the inspected object 1 that moves without stopping scanning or traveling. Observation means 13 and a processing means 14 for specifying a leaked inspection object 1 or part. In addition, there is no restriction | limiting in the quantity of irradiation means 2a, 2b and transmission means 9a, 9b.

  The above-described traveling scanning unit 12a is constituted by a cart that travels by itself to inspect a plurality of objects 1 to be inspected. Travel control at the time of inspection can be any of control that travels at a planned speed and route, control that travels at a certain time or place, and control that a person travels by specifying the speed and route. is there.

  The travel scanning means 12b and 12c are constituted by multi-joint mechanisms capable of moving and rotating up and down, left and right, and back and forth.

  The observation means 13 is composed of an image sensor for obtaining a visible image in the measurement range of the light detection means 10a. Specifically, a CCD camera, a CMOS camera, or the like is applied as such observation means 13. If observation is difficult due to the laser beams emitted from the irradiation means 2a and 2b, a koto that is appropriately dimmed and observed with an optical filter or a polarizer is desirable.

  The processing unit 14 displays and stores a visible image when the light detection unit 10b detects the leakage of the detection target 4. Note that both wired and wireless can be applied between the processing means 14 and the observation means 13, and between the light detection means 10a and the light detection means 10b. Such processing means 14 is configured as, for example, a PC or an ITV monitor provided with a storage device such as a magnetic type or an optical type.

  Next, the operation will be described. The detection target 4 may include a plurality of components that emit polarized fluorescence. Therefore, in the present embodiment, a case where two components that emit polarized fluorescence are included in the detection target 4 will be described. In this case, the irradiation means 2a and 2b having wavelengths that are absorbed by the respective components are selected.

  The laser beams emitted from the irradiation means 2a and 2b are fiber-transmitted to the vicinity of the object 1 to be inspected by the transmission means 9a and 9b, diffused and irradiated onto the object 1 to be inspected. When the detection target 4 leaks from the inspection object 1, polarized fluorescence is emitted from each component of the detection target 4. The polarized light and wavelength are selected and observed with respect to the polarized fluorescence by the polarization selection means 5 and the spectroscopic means 6.

  For the polarization selection means 5, the main axis is rotated so that the noise light observed in the light detection means 10b is minimized. In this state, the exit sides of the transmission means 9 a and 9 b are respectively twisted and rotated, and the polarization directions of the polarized fluorescence of the respective components that change in accordance with this are aligned with the main axis of the polarization selection means 5. As a result, polarized fluorescence of all components can be selected and observed by polarization, and noise light can be minimized.

  As for the spectroscopic means 6, although the polarized fluorescence of each component is mixed, a wavelength band in which the emission intensity of the polarized fluorescence is larger than that of noise light is selected. Thereby, polarized fluorescence of all the components can be selected and observed by wavelength. As a result, the light detection means 10a can integrate and observe all the polarized fluorescence of each component selected by polarization and wavelength, and the polarized fluorescence is measured with high SN. For this reason, in the light detection means 10b, the signal level is increased by the polarized fluorescence of the detection target 4, and the polarization fluorescence signal 11 can be obtained, and the presence or absence of leakage of the detection target 4 can be detected.

  Therefore, when a plurality of components that emit polarized fluorescence are included in the detection target 4, polarized fluorescence can be emitted from each component. In the light detection means 10a, all the polarized fluorescence of each component selected by the polarization and wavelength can be integrated and observed, and the polarized fluorescence can be measured with high SN. As a result, the light detection means 10b can detect the presence or absence of leakage of the detection target 4 based on the signal level even in an environment of noise light.

  In addition, in the case of the inspecting object 1 that moves without stopping scanning or traveling, it may be required to specify the inspecting object 1 or the part that is leaking. In such a case, the traveling scanning unit 12a appropriately moves to each object 1 to be detected, and the traveling scanning units 12b and 12c are continuously scanned to detect leakage of the detection target 4.

  On the other hand, when the inspection object 1 moves, the traveling scanning means 12a, 12b, 12c are stopped and the detection of the detection target 4 is continuously detected. At the same time, the observation means 13 observes a visible image of the inspection object 1 or part. When the signal level rises in the light detection means 10b and the leakage of the detection target 4 is detected, an instruction signal is sent from the light detection means 10b to the processing device 14, and the inspected object 1 having a leakage in the processing device 14 Is displayed and saved. As a result, it is possible to specify the inspected object 1 or the part having leakage. Further, in the case of the imaging means 7a and 7b, it is possible to identify the leakage site and grasp the leakage status by superimposing the polarized fluorescence image 8 and the visible image.

  Therefore, according to the present embodiment, the visible image when the leakage of the detection target 4 is detected by the light detection unit 10b is displayed and stored on the processing device 14 by simultaneously measuring the visible image by the observation unit 13. be able to. As a result, it is possible to specify the inspected object 1 or the part having the leakage without stopping the scanning or running or in the case of the inspected object 1 that moves. Further, when the imaging means 7a and 7b are used, it is possible to identify the leaked part and grasp the leaked state by superimposing the polarized fluorescence image 8 and the visible image.

The block diagram which shows 1st Embodiment of this invention. The block diagram which shows 2nd Embodiment of this invention. The block diagram which shows 3rd Embodiment of this invention. The block diagram which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 To-be-inspected object 2a, b Irradiation means 3 Polarization direction control means 4 Detection object 5 Polarization selection means 6 Spectroscopic means 7a, b Imaging means 8 Polarized fluorescence image 9a, b Transmission means 10a, b Light detection means 11 Polarization fluorescence signal 12a, b, c Scanning means 13 Observation means 14 Processing means

Claims (4)

A leak detection device that detects a leak of a detection target that emits fluorescence when irradiated with laser light,
An irradiation means for irradiating the object to be inspected with a plurality of polarized laser beams having different irradiation wavelengths ;
Polarization selection means for selecting and observing the polarization of polarized fluorescence with respect to polarized fluorescence of each irradiation wavelength emitted by irradiation of polarized laser light by the irradiation means,
A spectroscopic means for selecting and monitoring the wavelength band in which the intensity of the polarized fluorescence of each component is increased, and integrating and observing the polarized fluorescence of each component;
And a light detection means for detecting polarized fluorescence whose polarization and wavelength are selected,
The irradiation means includes a laser light source and an optical fiber that transmits a polarized laser beam while maintaining a polarization state. The polarization direction of the laser beam is obtained by twisting and rotating the exit side of the polarized laser beam of the optical fiber. A leak detection apparatus characterized by being configured to be variable . 2. The leak detection apparatus according to claim 1 , wherein the light detection means picks up an image of polarized fluorescence whose polarization and wavelength are selected, and detects and detects the leak. And observation means for obtaining a visible image of the scanning means or moving the object to be inspected to inspect a plurality of the inspection object, claim 1 or a processing means for identifying the object to be tested or moiety, leakage The leak detection apparatus according to claim 2 . A leakage detection method for detecting leakage of a detection target that emits fluorescence by irradiation with a laser beam,
A polarized laser beam transmission step of transmitting a plurality of polarized laser beams having different irradiation wavelengths while maintaining a polarization state by an optical fiber;
A polarization direction changing step of changing the polarization direction of the polarized laser beam by twisting the exit side of the polarized laser beam of the optical fiber;
An irradiation step of irradiating the object to be inspected with the polarized laser beam;
A polarization selection step of selecting and observing the polarization of the polarized fluorescence with respect to the polarized fluorescence of each irradiation wavelength emitted by irradiation of the polarized laser beam by the irradiation means;
A spectroscopic step of selecting and observing the polarized fluorescence of each component by selecting a wavelength band where the intensity of the polarized fluorescence of each component is increased,
And a light detection step of detecting polarized fluorescence whose polarization and wavelength are selected.

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