JP5288484B2 - Particle visualization device - Google Patents

Description

  The present invention relates to a particle visualization apparatus used in a measurement technique of behavior of fine particle groups that densely fly in a gas or liquid. In particular, the present invention provides probe-type particle visualization for particle imaging / measurement systems that measure particle characteristics such as particle velocity, particle diameter, and particle shape of individual particles in a group of finely dispersed particles flying in gas or liquid. It relates to the device.

  As a method for measuring the particle velocity and particle diameter of each particle contained in a group of fine particles dispersed and flying in a gas or liquid, a phase Doppler method, a shadow Doppler method, a direct imaging method, a laser interference imaging method, and the like are known. .

  As described in Non-Patent Document 1, the direct imaging method illuminates from behind the particles flying in a dispersed manner and takes a shadow photograph of the particles with an imaging device such as a CCD camera arranged at a position facing the illumination device. Thus, this is a technique for measuring the speed and size of individual particles. In direct imaging, a measurement system can be configured using a relatively inexpensive device, and it can be easily measured without the need for complicated adjustments and calibrations. Has been used.

  In the direct imaging method, the particle diameter, the particle shape, and the like can be measured by image analysis of a shadow photograph of the captured particle. In addition, by double exposure shooting, high-speed camera shooting, frame laser shooting using a pulse laser and a digital CCD camera, etc., the flying particles are continuously shot at short time intervals to measure the flying distance of the particles. By dividing the measured value by the time interval, the flying speed of the particles can be measured.

  The direct imaging method can be measured without being affected by the particle shape, and is advantageous in that it has a wider range of application than the phase Doppler method and laser interference imaging method, which assume that the particle shape is a true sphere. It is.

  In such a direct imaging method, when the fine particles are illuminated from the front, complicated light scattering characteristics depending on the particle shape and material are exhibited. For this reason, the photographed particle image does not reflect the size or shape of the particle, and therefore cannot satisfy the requirements for particle measurement. Under such circumstances, in the direct imaging method, it is necessary to perform background illumination that illuminates particles from the back. Therefore, as shown in Patent Document 1, the illumination device and the imaging device sandwich the particle group to be measured. Are arranged at positions facing each other.

JP 2001-74638 A

Chigier, N., 1983 "DROP SIZE AND VELOCITY INSTRUMENTATION" (Progress in Energy and Combustion Science, Vol. 9, pp. 155-177)

  Thus, in the device configuration in which the illumination device and the imaging device are arranged to face each other, the imaging device and the illumination device must be arranged in a separated / separated state, and therefore the overall shape and overall dimensions of the device are large. Turn into.

  In addition, it is necessary to connect a power supply line, a control signal line, and the like to both the imaging device and the illumination device. For this reason, it is difficult to integrate the drive system and the control system of both devices in a compact manner.

  Furthermore, when measuring the inside of a particle group that flies densely in a gas or liquid, an image pickup device and an illumination device are installed or inserted in the vicinity of the measurement location inside the particle group, and the particle group existing in the foreground. However, in a conventional measuring device whose outer dimensions have become larger as a result of separating the imaging device and the lighting device, such a usage pattern or layout is structurally adopted. Even if it is difficult to adopt, there is a problem that the flying state of the particle group is changed, which makes it difficult to accurately measure the inside of the dense particle group.

  The present invention has been made in view of such a problem, and an object of the present invention is to enable photographing and illumination from the same direction and to integrate the photographing system and the illumination system as a compact probe. The present invention provides a particle visualization device for a particle imaging / measurement system that can be inserted into a dense particle group and thereby can accurately measure the particle feature amount inside the dense particle group. .

In order to achieve the above object, the present invention provides a particle visualization apparatus that is used or incorporated in an optical system that images a fluid including flying particle groups and measures the particle characteristic amount of particles in the fluid.
An optical path that supplies illumination light for imaging from the base end side of the shaft portion toward the tip portion, and a through channel that passes through the shaft portion so as to cross the optical path, and the flying particle group A probe part inserted into the flow;
A first reflecting means that is disposed at a distal end of the probe unit, reflects the illumination light, and directs background light to image the particles passing through the through channel;
Characteristic conversion means for changing or converting the characteristics of the illumination light or the background light so that the characteristics of the illumination light incident on the first reflecting means and the characteristics of the background light are different;
There is provided a particle visualizing device comprising: a second reflecting means for deflecting, turning, or reflecting the background light that has passed through the flow path toward a side of the probe.

  According to the particle visualization apparatus of the present invention, by inserting the probe portion into the densely flying particle group, the particles suspended in the fluid are allowed to flow into the through channel of the probe portion and the particles are photographed. Therefore, it is possible to acquire particle image data by using background light for measuring particle feature quantities such as particle size, area, diameter, shape, particle velocity, and the like at a measurement location inside the particle group.

  Further, the particle visualization apparatus of the present invention is a measurement probe (probe) configuration in which two optical systems, an optical system for supplying background illumination and an optical system for photographing a particle group, are provided on the same shaft or cylinder. It has a probe-like device configuration. Such a probe-type particle visualization apparatus is extremely advantageous because the detection unit or detection unit can be easily inserted into a desired position inside the particle group.

  Furthermore, according to the present invention, a direct imaging method in which imaging and illumination are performed from the same direction is realized by supplying illumination light from the direction of the optical system for imaging the particle group and converting it to background light. .

  In addition, since the particle visualization device of the present invention has a built-in function of providing background illumination, the flying particle is imaged within a limited measurement space without separating the imaging device and the illumination device. be able to.

  From another viewpoint, the present invention includes a particle visualization device having the above-described configuration and an imaging device having an imaging surface for the background light, and optically shoots the characteristics of the particles in the fluid. Provided is a particle imaging / measurement system characterized by measuring feature quantities.

  According to the particle imaging / measurement system of the present invention, a probe unit in which the imaging system and the illumination system are integrated in a compact manner is inserted into the dense particle group, thereby accurately determining the particle feature amount inside the dense particle group. It can be measured.

  According to the particle visualization device of the present invention, it is possible to photograph and illuminate from the same direction, and can be inserted into the dense particle group by integrating the photographing system and the illumination system as a compact probe, This makes it possible to accurately measure the particle feature amount inside the dense particle group.

It is the top view, side view, and back view which show the structure of the particle | grain visualization apparatus which concerns on the suitable Example of this invention. It is a schematic perspective view which shows the whole apparatus system structure of the particle | grain imaging / measurement system containing a particle | grain visualization apparatus. It is a block diagram which shows roughly the internal structure and function of the particle | grain visualization apparatus which concerns on 1st Example of this invention. It is a block diagram which shows roughly the internal structure and function of the particle | grain visualization apparatus concerning 2nd Example of this invention. It is a block diagram which shows roughly the internal structure and function of the particle | grain visualization apparatus concerning 3rd Example of this invention.

  In a preferred embodiment of the present invention, the characteristic of the light to be changed or converted by the characteristic converting means is the wavelength, phase and / or waveform of the light.

  Preferably, a 2nd reflection means reflects background light in the direction orthogonal to the axial center of a probe part. More preferably, the second reflecting means transmits or reflects at right angles according to the polarization component of the incident linearly polarized light, or a part (for example, half) of the incident light. It consists of a beam splitter (for example, a 50/50 beam splitter) that transmits only the remaining light amount (for example, half), that is, a non-reflective portion of the laser light and travels straight. Preferably, the probe unit includes a borescope having a circular cross section having an optical path in an axial center portion, and an adapter having a circular cross section detachably connected to a distal end portion of the borescope, and the first reflecting means includes a background. Light is reflected in the axial direction of the probe portion.

  In a preferred embodiment of the present invention, the second reflecting means transmits light having substantially the same characteristics as the illumination light incident on the first reflecting means, while the characteristic converting means changes or converts the characteristics. And selectively transmits light and reflects the reflected light.

  In another preferred embodiment of the present invention, an optical filter is interposed between the second reflecting means and the imaging device, and the optical filter has substantially the same characteristics as the characteristics of the illumination light incident on the first reflecting means. The characteristic conversion means has a selective light transmission property that changes the characteristic or transmits the converted light.

  Preferably, the characteristic conversion means has the following configuration.

(1) The characteristic converting means has a polarizing element that converts the polarization direction of light, and the polarizing element constitutes a wave plate disposed between the through channel of the shaft portion and the first reflecting means. A polarization element is used to change the polarization direction of the illumination light to form background illumination, so that a component in which illumination light supplied from the imaging direction is scattered by particles, and background light supplied as background illumination, Can be separated by utilizing the difference in the polarization direction, so that only the background illumination components necessary for the direct photographing method can be extracted.

(2) The characteristic converting means has a fluorescent light emitting element that changes the wavelength of light, and the fluorescent light emitting element also constitutes a reflecting surface of the first reflecting means. By using a fluorescent light-emitting element to convert the illumination light into light of different wavelengths to form background illumination, the illumination light supplied from the shooting direction is scattered by particles and the background light supplied as background illumination. Can be separated by utilizing the difference in wavelength, so that only the background illumination components necessary for the direct photographing method can be extracted.

(3) The characteristic conversion means includes a wavelength conversion element that converts a light component into a harmonic component, and the wavelength conversion element also constitutes a reflection surface of the first reflection means. By converting the illumination light component into a harmonic component using a wavelength conversion element to form background illumination, the illumination light supplied from the photographing direction is scattered by particles, and the background supplied as background illumination. The light can be separated by utilizing the difference in wavelength, which makes it possible to extract only the background illumination components necessary for direct imaging.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a plan view, a side view, and a rear view showing a configuration of a particle visualization apparatus according to a preferred embodiment of the present invention.

  The particle visualization device 1 is an integral and compact measurement probe type device having a background illumination function for particle imaging, and includes a probe section 1a having a circular cross section that can be inserted into a flow path of a particle group. The probe unit 1a includes a borescope 3 having an optical path for supplying light for photographing at an axial center portion, and an adapter 4 concentrically and integrally connected to a distal end portion of the borescope 3.

  The base end portion of the borescope 3 is detachably attached to the pedestal portion 2. For example, a screw portion that is screwed into a screw portion formed in the pedestal portion 2 is formed at the base end portion of the borescope 3, and the screw portions are screwed together by relative rotation of the borescope 3 and the pedestal portion 2. Thus, the borescope 3 can be integrally attached to or removed from the pedestal portion 2.

  The adapter 4 is detachably attached to the distal end portion of the borescope 3. For example, a screw part that is screwed to each other is formed at a joint portion between the borescope 3 and the adapter 4, and the screw parts are screwed together or released by relative rotation of the adapter 4 and the borescope 3. It can be attached to the tip of the borescope 3 or removed from the tip of the borescope 3. When particles or the like adhere to the adapter 4 during use and the adapter 4 is contaminated, only the adapter 4 can be removed and cleaned.

  A slit 5 is formed in the adapter 4 as a through channel through which particles pass. The slit 5 is a gap opened over substantially the entire circumference of the adapter 4 and is open to the periphery except for the connecting piece portion 5a. The slit 5 penetrates the probe portion 1a in a direction crossing the optical path extending from the axial core portion of the borescope 3. The probe portion 1a is inserted into the flow P of flying particle groups indicated by broken line arrows in FIG. 1B, and a part of the flying particle groups passes through the through holes or through holes formed by the slits 5. Particles that pass through the slit 5 are measurement targets of the particle imaging / measurement system.

  The adapter 4 includes a quarter wavelength plate 6 and a reflection plate 7. The reflection plate 7 is disposed at the most distal end portion of the probe unit 1 a, and the quarter wavelength plate 6 is disposed between the reflection plate 7 and the slit 5. The quarter-wave plate 6 constitutes characteristic conversion means, and the reflection plate 7 constitutes first reflection means for directing background light for particle photography into the slit 5.

  The pedestal unit 2 incorporates a beam splitter 8 and a half-wave plate 9. The beam splitter 8 constitutes a second reflecting means for reflecting the background light that has passed through the slit 5 toward the side of the probe unit 1a.

  An imaging device 10 such as a digital CCD camera is connected to the side portion of the pedestal portion 2 or arranged adjacent thereto. The light reflected laterally by the beam splitter 8 is incident on the light receiving unit of the imaging device 10. The imaging device 10 has an imaging surface for background light, and images the particles of the particle group through the optical path of the axial core portion of the probe unit 1a.

  FIG. 2 is a schematic perspective view showing the overall configuration of the particle imaging / measurement system including the particle visualization device 1.

  The particle imaging / measurement system includes a particle visualization device 1, an imaging device 10, an optical lens unit 11, a laser device 12, a PC (personal computer) 13, a pulse generator 14, and a delay generator 15. The individual devices constituting the particle imaging / measurement system are connected to each other via a control signal line indicated by a virtual line (one-dot chain line), visualize the particles passing through the slit 5 and take an image. At the same time, the particle feature amount (particle velocity, particle diameter, particle shape, etc.) is measured using a particle image processing algorithm.

For example, the following digital CCD camera can be suitably used as the imaging device 10.
・ Product name: JAI "jAi CV-M2CL"
Effective pixel size: 1600 (h) x 1/200 (v)
・ CCD element size: 11.84mm (h) x 8.88mm (v)
・ Number of bits: 10bit
・ Shooting speed: 30fps / dual channel

  The imaging device 10 is connected to the pedestal 2 of the particle visualization device 1 via a C-mount relay lens (not shown) or the like. As the C-mount relay lens interposed between the imaging device 10 and the particle visualization device 1, for example, “C-mount relay lens T732RFP” manufactured by Machida Mfg. Co., Ltd. can be suitably used.

The laser device 12 supplies illumination light for photographing, and a double pulse Nd: YAG laser (neodymium / yag laser) or the like can be used as the laser device 12. For example, the following Nd: YAG laser can be suitably used as the laser device 12.
-Product name: “Pegasus by New Wave Research
PIV laser "
・ Maximum emission frequency: 10KHz
・ Output: 20mJ / pulse @ 537nm
・ Pulse width: 10 to 180ns

  In this embodiment, a linearly polarized laser light source and an Nd: YAG laser (1 unit) having a wavelength of 532 nm are used as the laser device 12. The optical lens unit 11 is used to adjust the laser beam of the laser device 12 to an appropriate thickness, width and angle. The optical lens unit 11 is composed of a single lens or has a configuration in which a plurality of lenses are combined. The PC 13 reads and stores the image data of the image taken by the imaging device 10 and saves the image data, and adjusts the length of the minute time interval of the delay generator 15. The pulse generator 14 generates a synchronization signal. As the pulse generator 14, "WAVTEK" manufactured by Toyo Technique Co., Ltd. can be suitably used. The delay generator 15 controls the pulse interval of the laser device 12. As the delay generator 15, “VSD1000” manufactured by Flowtech Research, Inc. can be suitably used.

  A pulse signal from the pulse generator 14 is input to the delay generator 15. The delay generator 15 outputs a signal delayed by a predetermined time interval (minute time) based on the pulse signal of the pulse generator 14 to the laser device 12 and the imaging device 10 as a trigger signal. The laser device 12 to which the trigger signal of the delay generator 15 is input emits a single pulse laser beam or a double pulse laser beam with a predetermined delay time set. The imaging device 10 to which the trigger signal of the delay generator 15 is input captures at least one image in the particle diameter imaging and the like, and in the particle velocity measurement and the like, at least one set (2) with a minute time interval. Image). In actual measurement, multiple images or multiple sets of images are taken. Image data of an image taken by the imaging device 10 is output to the PC 13, stored in the PC 13, and stored.

  The particle visualization apparatus 1 constituting such a particle imaging / measurement system is configured to convert incident laser light into background illumination by polarization illumination using the polarization characteristics of laser light, as described below. . The probe unit 1a of the particle visualization apparatus 1 can be designed, for example, under the design conditions of an outer diameter of 8 mm, a length of 160 mm, a focal length of 2 mm, and a depth of field of 100 μm.

  FIG. 3 is a block diagram schematically showing the internal configuration and functions of the particle visualization apparatus 1.

  The principle of polarized illumination is shown in FIG. With reference to FIG. 3, the structure and function of the particle | grain visualization apparatus 1 of this invention are demonstrated.

  The linearly polarized laser beam L emitted from the laser device 12 is adjusted to an appropriate width and thickness by the optical lens unit 11 and enters the particle visualization device 1 as illumination light. The polarization azimuth of the laser beam L incident on the particle visualization device 1 is adjusted by the half-wave plate 9. The particle visualization apparatus includes a beam splitter 8, and the beam splitter 8 includes a polarization beam splitter that transmits light or reflects at right angles according to a polarization component of incident linearly polarized light. The laser beam emitted from the half-wave plate 9 passes through the beam splitter 8 and enters the borescope 3 as indicated by an arrow α. The laser beam passes through the optical path in the borescope 3 and enters the quarter wavelength plate 6, and the quarter wavelength plate 6 converts the polarization state of the laser beam into circularly polarized light.

  The circularly polarized laser beam is incident on and reflected by the reflecting plate 7 as indicated by an arrow β and passes through the quarter-wave plate 6 again. The quarter wave body 6 converts the deflection state of the laser beam into linearly polarized light. The laser beam that has passed through the quarter wave body 6 passes through the borescope 3 and enters the beam splitter 8. The polarization azimuth angle of the laser beam incident on the beam splitter 8 differs (rotates) by an angle of 90 ° with respect to the polarization azimuth angle of the laser beam (arrow α) of the illumination light previously transmitted through the beam splitter 8. For this reason, the laser beam incident on the beam splitter 8 from the borescope 3 is reflected by the 45 ° plane of the beam splitter 8 as shown by an arrow γ, and forms an image on the image plane of the imaging device 10.

  The particle Q to be measured that passes through the slit 5 is a particle that exists between the beam splitter 8 and the quarter-wave plate 6, but when there is no particle in the slit 5, the laser beam is An image is formed on the imaging device 10 as background light.

  As described above, according to the particle visualization apparatus 1 having an optical system using polarized illumination, the light source for background light is not disposed at a position that is separated from and opposed to the imaging apparatus 1, and is efficient by a compact apparatus configuration. It is possible to secure background light for photographing. In order to effectively irradiate the particle Q with the laser beam, the borescope 3 is disposed between the beam splitter 8 and the slit 5. Even when attached, the background light of the polarized illumination forms a bright background on the image plane of the imaging device 10.

  The particle Q in the slit 5 is a particle that passes through the slit 5 between the borescope 3 and the quarter-wave plate 6, and the laser light reflected from the particle Q passes through the quarter-wave plate 6. The reflected light of the laser beam, that is, the reflected light of the laser beam of the illumination light that has passed through the beam splitter 8, has a deflection characteristic (deflection azimuth angle) that allows the total amount of light to pass through the beam splitter 8. Accordingly, the reflected light from the particle Q is not reflected by the 45 ° plane of the beam splitter 8 and is transmitted through the beam splitter 8 as indicated by a broken line arrow δ in FIG. Does not image. That is, the particle Q appears as a black block, point, or region in the image of the imaging device 10. As a result, the particle imaging system (FIG. 2) can easily identify the particle and its background, so that the particle size, particle velocity, and the like can be measured using the particle image processing algorithm.

  As described above, the particle visualization device 1 supplies the imaging laser light from the proximal end side of the probe portion 1a toward the distal end portion thereof, and inside the adapter 4 attached to the distal end of the probe portion 1a. Converts laser light into background light. Therefore, according to the particle visualization apparatus 1, both photographing and illumination can be performed from substantially the same direction. For this reason, the installation space for the light source for background light irradiation, which is required in the conventional configuration in which the background illumination is irradiated from the opposite side of the particle group to the imaging device, is omitted, and the measurement condition setting and the measurement method setting are performed. In addition, the degree of freedom, convenience, applicability, etc. of measurement system design can be greatly improved.

  FIG. 4 is a block diagram schematically showing the internal configuration and functions of the particle visualization apparatus according to the second embodiment of the present invention. In FIG. 4, the same reference numerals are assigned to substantially the same components or components as the components or components shown in FIGS.

  The particle visualization apparatus 1 according to the present embodiment includes a reflection plate 17 having a reflection surface formed of a fluorescent light emitting element, and an optical filter 16 interposed between the beam splitter 18 and the imaging device 10. The optical filter 16 has wavelength selectivity, does not transmit light having a wavelength before being reflected by the fluorescent light emitting element of the reflecting plate 17, and cuts the light, but has a wavelength range reflected by the fluorescent light emitting element of the reflecting plate 17. Transmit light. In addition, the particle | grain visualization apparatus 1 of a present Example is not provided with the 1/4 wavelength body 6 and the 1/2 wavelength plate 9 which were provided in 1st Example.

  The principle by which the particle visualization apparatus 1 of the present embodiment converts laser light into background illumination will be described with reference to FIG.

  The laser beam L emitted from the laser device 12 is adjusted to an appropriate width and thickness by the optical lens unit 11 as necessary, and enters the particle visualization device 1. The laser beam L enters the beam splitter 18 as indicated by an arrow α. The beam splitter 18 reflects the incident laser beam by a partial light amount (for example, half light amount), and transmits the remaining light amount (for example, half light amount), that is, a non-reflective laser beam to travel straight. A splitter (eg, a 50/50 beam splitter).

  The laser beam that has passed through the beam splitter 18 passes through the borescope 3 and travels further straight, and is reflected by the reflecting surface of the reflecting plate 17 as indicated by an arrow β. The fluorescent light emitting element constituting the reflecting surface of the reflecting plate 17 converts the wavelength of the reflected light into a wavelength different from the wavelength of the incident light. Therefore, the wavelength of light changes before and after reflection by the reflecting plate 17. The optical filter 16 transmits only the light whose wavelength is changed by the fluorescent light emitting element of the reflection plate 17.

  The laser beam reflected by the reflecting plate 17 passes through the optical path of the borescope 3 toward the beam splitter 18 as indicated by an arrow γ, and the beam splitter 18 advances a part of the laser beam (for example, 50%) straight. (Arrow δ), and the remaining part (for example, 50%) is reflected in the direction of the imaging device 10. The laser beam reflected toward the imaging device 10 passes through the optical filter 16 and enters the imaging device 10, and forms a bright background on the image plane of the imaging device 10.

  On the other hand, the light reflected from the particles Q in the slit 5 also passes through the borescope 3, and the beam splitter 18 advances a part of the light (for example, 50%) straight, and the remaining part of the light (for example, 50%). Is reflected in the direction of the imaging device 10. The light reflected from the particles has the same wavelength as the laser beam L (arrow α) incident on the particle visualization device 1. For this reason, the light reflected from the particles is cut by the optical filter 16. That is, the light incident on the imaging device 10 is only the reflected light that has been reflected by the reflecting plate 17 and has a changed wavelength, and the reflected light of the particles Q having the same wavelength as the light before entering the reflecting plate 17 is the reflected light. Are completely shielded by the optical filter 16 and do not enter the imaging device 10. Therefore, since the particles are displayed as black masses, points, or regions in the image of the imaging device 10, the particles and their background can be easily identified.

  FIG. 5 is a block diagram schematically showing the internal configuration and functions of the particle visualization apparatus according to the third embodiment of the present invention. In FIG. 5, the same reference numerals are assigned to substantially the same components or components as the components or components shown in FIGS.

  The particle visualization apparatus 1 according to the present embodiment includes a reflection plate 27 having a reflection surface formed by a laser wavelength conversion element, and an optical filter 26 interposed between the beam splitter 28 and the imaging device 10. The optical filter 26 has wavelength selectivity and does not transmit the light having the wavelength before being reflected by the laser wavelength conversion element of the reflection plate 27, but cuts the light, but after the laser wavelength conversion element of the reflection plate 27 is reflected. Transmits light of the wavelength. In addition, the particle | grain visualization apparatus 1 of a present Example is not provided with the 1/4 wavelength body 6 and the 1/2 wavelength plate 9 which were provided in 1st Example.

  The principle by which the particle visualization apparatus 1 of the present embodiment converts laser light into background illumination will be described with reference to FIG.

  The laser beam L emitted from the laser device 12 is adjusted to an appropriate width and thickness by the optical lens unit 11 as necessary, and enters the particle visualization device 1. The laser beam L enters the beam splitter 28 as indicated by an arrow α. The beam splitter 28 reflects the incident laser light by a part (for example, half) of the light amount, and transmits the remaining part (for example, half) of the light amount, that is, a non-reflective portion of the laser light, so as to travel straight. (For example, a 50/50 beam splitter).

  The straight laser beam passes through the borescope 3 and further advances straight, and is reflected by the reflecting surface of the reflecting plate 27 as indicated by an arrow β. The laser wavelength conversion element that constitutes the reflection surface of the reflection plate 27 includes a laser harmonic generation element that converts the wavelength of reflected light to a wavelength different from the wavelength of incident light. The wavelength of the light reflected by the laser wavelength conversion element is converted to ½ or の of the wavelength of the light before reflection, and thus the wavelength of the light changes before and after reflection by the reflection plate 27. The optical filter 26 transmits the light whose wavelength is changed in this way, while shielding and cutting the light before wavelength conversion.

  As indicated by an arrow γ in FIG. 5, the laser beam reflected by the reflector 27 passes through the borescope 3 toward the beam splitter 28 and is partially (for example, half) by the beam splitter 28 as indicated by an arrow δ. The remaining amount of light (half) is reflected in the direction of the imaging device 10. The laser beam reflected toward the imaging device 10 passes through the optical filter 26 and enters the imaging device 10, and forms a bright background on the image plane of the imaging device 10.

  On the other hand, the light reflected from the particle Q passes through the borescope 3, and a part (for example, half) of the light amount travels straight by the beam splitter 28, and the remaining part (for example, half) of the light is directed toward the imaging device 10. Reflect on. The light reflected from the particles has the same wavelength as the wavelength of the laser beam L (arrow α) incident on the particle visualization device 1.

  The optical filter 26 cuts light having the same wavelength as that of the light before entering the reflection plate 27 (arrow α), and allows only the reflected light whose wavelength has been changed by the reflection plate 27 to enter the imaging device 10. Accordingly, the light reflected from the particle Q is substantially completely cut by the optical filter 26, so that the reflected light of the particle Q is not reflected on the imaging device 10. That is, the particles in the image appear on the image as black masses, points, or areas, so that the particles and their background can be easily identified.

  The preferred embodiments and examples of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments and examples, and is within the scope of the present invention described in the claims. Various modifications or changes are possible.

  For example, the mechanical configuration, cross-sectional structure, dimensions, shape, form, and the like of the probe part and the pedestal part can be changed according to the present invention.

  In addition, the configuration and the like of the particle imaging / measurement system to which the particle visualization apparatus is connected can be arbitrarily changed within the scope of the object of the present invention.

  Furthermore, in the practice of the present invention, various improvements such as painting on the inner wall surface of the borescope can be considered or adopted for improving the image quality.

  The present invention is a technique for measuring the behavior of fine particle groups that fly densely in a gas or liquid, such as diesel exhaust, boiler exhaust, pulverized coal combustion, fuel spray, cleaning spray, spray coating, spray coating, powder transportation, It is applied to basic measurement technology in a wide range of fields such as pesticide application. According to the present invention, by inserting a compact probe portion into the flow of the dense particle group, it becomes possible to accurately measure the particle feature amount inside the dense particle group, and its practical effect is Is remarkable.

DESCRIPTION OF SYMBOLS 1 Particle | grain visualization apparatus 2 Base part 3 Borescope 4 Adapter 5 Slit 6 1/4 wavelength plate 7 Reflection plate 8, 18, 28 Beam splitter 9 1/2 wavelength plate 10 Imaging device 11 Optical lens unit 12 Laser apparatus 13 PC
14 Pulse generator 15 Delay generator 16, 26 Optical filter 17 Reflector (fluorescent light emitting element)
27 Reflector (laser wavelength conversion element)

Claims (8)

In a particle visualization apparatus that is used or incorporated in an optical system that images a fluid including flying particle groups and measures the particle feature amount of particles in the fluid,
An optical path that supplies illumination light for imaging from the base end side of the shaft portion toward the tip portion, and a through channel that passes through the shaft portion so as to cross the optical path, and the flying particle group A probe part inserted into the flow;
A first reflecting means that is disposed at a distal end of the probe unit, reflects the illumination light, and directs background light to image the particles passing through the through channel;
Characteristic conversion means for changing or converting the characteristics of the illumination light or the background light so that the characteristics of the illumination light incident on the first reflecting means and the characteristics of the background light are different;
A particle visualization apparatus comprising: a second reflecting means for deflecting, turning, or reflecting the background light that has passed through the flow path toward a side of the probe.   The particle visualization apparatus according to claim 1, wherein the characteristic of the light to be changed or converted by the characteristic conversion unit is a wavelength, a phase, and / or a waveform of the light.   The second reflecting means transmits light having substantially the same characteristics as the characteristics of the illumination light incident on the first reflecting means, while reflecting the light whose characteristic has been changed or converted by the characteristic converting means. The particle visualization apparatus according to claim 1, wherein the particle visualization apparatus has selective light transmission and reflection properties. The optical filter further includes an optical filter interposed between the second reflecting means and the imaging device having the imaging surface for the background light, and the optical filter transmits the illumination light incident on the first reflecting means. 2. The light transmitting apparatus according to claim 1, wherein the light transmitting means has a selective light transmitting property for preventing the transmission of light having substantially the same characteristic as the characteristic, while the characteristic converting means changes the characteristic or transmits the converted light. Alternatively, the particle visualization apparatus according to 2.   The particle visualization apparatus according to claim 1, wherein the characteristic conversion unit includes a polarizing element that converts a polarization direction of light.   The particle visualization apparatus according to claim 1, wherein the characteristic conversion unit includes a fluorescent light emitting element that changes a wavelength of light.   The particle visualization apparatus according to claim 1, wherein the characteristic conversion unit includes a wavelength conversion element that converts a light component into a harmonic component.   A particle visualization device according to any one of claims 1 to 7, and an imaging device having an imaging surface for the background light, wherein the feature of the particles in the fluid is optically photographed to obtain a particle feature amount of the particles. Particle imaging / measurement system characterized by measurement.

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