WO2016143696A1 - パーティクルカウンタ - Google Patents
パーティクルカウンタ Download PDFInfo
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- WO2016143696A1 WO2016143696A1 PCT/JP2016/056787 JP2016056787W WO2016143696A1 WO 2016143696 A1 WO2016143696 A1 WO 2016143696A1 JP 2016056787 W JP2016056787 W JP 2016056787W WO 2016143696 A1 WO2016143696 A1 WO 2016143696A1
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- Prior art keywords
- light
- detection
- interference
- optical system
- scattered
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- 239000002245 particle Substances 0.000 title claims abstract description 125
- 238000001514 detection method Methods 0.000 claims abstract description 111
- 230000003287 optical effect Effects 0.000 claims abstract description 64
- 239000012530 fluid Substances 0.000 claims abstract description 38
- 230000005540 biological transmission Effects 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 5
- 238000001914 filtration Methods 0.000 claims description 4
- 230000001678 irradiating effect Effects 0.000 claims description 3
- 238000005259 measurement Methods 0.000 description 10
- 239000000126 substance Substances 0.000 description 10
- 238000010586 diagram Methods 0.000 description 6
- 230000005684 electric field Effects 0.000 description 4
- 230000033001 locomotion Effects 0.000 description 4
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- 230000001427 coherent effect Effects 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 238000002296 dynamic light scattering Methods 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- 230000005653 Brownian motion process Effects 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 2
- 238000005537 brownian motion Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000010287 polarization Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 235000012431 wafers Nutrition 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052594 sapphire Inorganic materials 0.000 description 1
- 239000010980 sapphire Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
Images
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/10—Investigating individual particles
- G01N15/14—Optical investigation techniques, e.g. flow cytometry
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/02—Investigating particle size or size distribution
- G01N15/0205—Investigating particle size or size distribution by optical means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/06—Investigating concentration of particle suspensions
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/10—Investigating individual particles
- G01N15/14—Optical investigation techniques, e.g. flow cytometry
- G01N15/1434—Optical arrangements
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/10—Investigating individual particles
- G01N15/14—Optical investigation techniques, e.g. flow cytometry
- G01N15/1456—Optical investigation techniques, e.g. flow cytometry without spatial resolution of the texture or inner structure of the particle, e.g. processing of pulse signals
- G01N15/1459—Optical investigation techniques, e.g. flow cytometry without spatial resolution of the texture or inner structure of the particle, e.g. processing of pulse signals the analysis being performed on a sample stream
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
- G01N21/45—Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N2015/0007—Investigating dispersion of gas
- G01N2015/0011—Investigating dispersion of gas in liquids, e.g. bubbles
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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- G01N2015/0038—Investigating nanoparticles
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N2015/0042—Investigating dispersion of solids
- G01N2015/0053—Investigating dispersion of solids in liquids, e.g. trouble
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/10—Investigating individual particles
- G01N15/14—Optical investigation techniques, e.g. flow cytometry
- G01N15/1434—Optical arrangements
- G01N2015/144—Imaging characterised by its optical setup
- G01N2015/1445—Three-dimensional imaging, imaging in different image planes, e.g. under different angles or at different depths, e.g. by a relative motion of sample and detector, for instance by tomography
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/10—Investigating individual particles
- G01N15/14—Optical investigation techniques, e.g. flow cytometry
- G01N15/1434—Optical arrangements
- G01N2015/1454—Optical arrangements using phase shift or interference, e.g. for improving contrast
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- G—PHYSICS
- G01—MEASURING; TESTING
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- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/10—Investigating individual particles
- G01N15/14—Optical investigation techniques, e.g. flow cytometry
- G01N2015/1486—Counting the particles
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/10—Investigating individual particles
- G01N15/14—Optical investigation techniques, e.g. flow cytometry
- G01N2015/1493—Particle size
Definitions
- the present invention relates to a particle counter.
- a particle counter as a device for measuring particles in a fluid which is a liquid such as a chemical solution, water, or a gas such as air.
- the particle counter irradiates a fluid containing particles with laser light, observes scattered light from the particles in the fluid, and counts the particles (see, for example, Patent Document 1).
- the impurity particles contained in the chemical used will affect the process, so the state of the chemical is managed by counting particles in the chemical using a particle counter. is doing.
- background light background light
- background noise is larger when measuring particles in the chemical solution than when measuring particles in water. For this reason, it is difficult to count particles having a small particle diameter (for example, 30 nm or less).
- Some particle counters use multi-divided light receiving elements and reduce the effective light receiving area at the ends, thereby reducing noise caused by background light and improving the S / N (Signal to Noise) ratio (for example, see Patent Document 1).
- the above-mentioned dynamic light scattering measuring apparatus can determine the particle size distribution, it is not suitable for counting particles in a fluid because it uses the Brownian motion of particles.
- the above-mentioned particle counter can count particles with a small particle size to some extent, it is required to count particles with a smaller particle size. For example, with the recent miniaturization of process rules in the manufacture of semiconductor wafers, a particle counter that counts particles with a particle size of 30 nm or smaller in chemicals is required.
- the present invention has been made in view of the above problems, and an object thereof is to obtain a particle counter capable of counting small particle diameter particles in a fluid with a good S / N ratio.
- the particle counter according to the present invention includes a light source that emits light, a light superimposing unit that spatially superimposes two lights, and one light out of a plurality of lights obtained by branching light from the light sources.
- Irradiation optical system that irradiates the fluid in the path to form a detection region, and among scattered light from particles contained in the fluid flowing in the detection region, scattered light in a direction different from the optical axis of the irradiation optical system, A detection optical system that is incident on the light superimposing unit; a reference optical system that causes another one of the plurality of lights to be incident on the light superimposing unit as reference light; and scattered light and reference light obtained by the light superimposing unit; Are received by a light receiving element, and a detection unit that generates a detection signal corresponding to the interference light, and a counting unit that counts particles based on the detection signal generated by the detection unit.
- the light superimposing unit is a beam splitter, and includes a first interference light based on a scattered light transmission component and a reference light reflection component, and a second interference light based on a scattered light reflection component and a reference light transmission component.
- the detection unit receives the first interference light and the second interference light by the two light receiving elements, and detects a difference between the electrical signal corresponding to the first interference light and the electrical signal corresponding to the second interference light as the detection signal. To do.
- FIG. 1 is a block diagram showing the configuration of the particle counter according to Embodiment 1 of the present invention.
- FIG. 2 is a perspective view showing an example of the flow cell 2 in FIG.
- FIG. 3 is a diagram for explaining the arrangement of the flow cell 2, the detection optical system 13, and the beam splitter 17 in FIG.
- FIG. 4 is a diagram for explaining the branching of light in the beam splitter 17 in FIG.
- FIG. 5 is a timing chart for explaining a detection signal obtained by the detection unit 4 in FIG.
- Embodiment 1 FIG.
- FIG. 1 is a block diagram showing a configuration of a particle counter according to Embodiment 1 of the present invention.
- the particle counter shown in FIG. 1 includes a light source 1, a flow cell 2, an optical system 3, a detection circuit 4, a filter 5, and a counting unit 6.
- the light source 1 is a light source that emits light having a stable frequency (here, laser light).
- the light source 1 emits highly coherent light in a single mode.
- a laser light source having a wavelength of 532 nm and an output of about 500 mW is used as the light source 1.
- the flow cell 2 forms a fluid flow path containing particles to be counted.
- the fluid containing the particles to be counted is a liquid.
- FIG. 2 is a perspective view showing an example of the flow cell 2 in FIG.
- the flow cell 2 is a transparent tubular member that is bent in an L shape and forms a bent flow path 2a.
- the fluid containing the particles to be counted is a chemical solution such as isopropyl alcohol, hydrofluoric acid solution, and acetone
- the flow cell 2 is made of, for example, sapphire.
- a detection region is formed by irradiating the fluid flowing in the flow path 2a with one of the lights obtained by branching the light from the light source 1.
- the optical system 3 includes a beam splitter 11, an irradiation optical system 12, a detection optical system 13, an attenuator 14, a mirror 15, a beam expander 16, a beam splitter 17, and condensing units 18a and 18b.
- the beam splitter 11 branches the light from the light source 1 into two lights.
- One of the lights branched by the beam splitter 11 (hereinafter referred to as measurement light) enters the irradiation optical system 12.
- another light (hereinafter referred to as reference light) among the lights branched by the beam splitter 11 enters the attenuator 14.
- the beam splitter 11 branches light from the light source 1 at a predetermined unequal ratio (for example, 90:10), and the intensity of the measurement light is greater than the intensity of the reference light.
- the irradiation optical system 12 transmits the measurement light from a direction (here, a vertical direction, that is, the Z direction in FIG. 2) different from the fluid traveling direction (the X direction in FIG. 2) in the flow path 2a of the flow cell 2.
- the fluid flowing in 2a is irradiated.
- the irradiation optical system 12 is a lens group as described in, for example, Japanese Patent Application Laid-Open No. 2003-270120, and shapes the laser light so as to increase the energy density.
- the detection optical system 13 causes the scattered light from the particles in the flow path 2a caused by the above-described measurement light irradiation to enter a predetermined incident surface of the beam splitter 17.
- a condensing lens is used, or an optical system having a pinhole for shielding background light and condensing lenses respectively disposed before and after the pinhole is used.
- the measurement light is incident on the flow path 2 a from a direction different from the optical axis of the detection optical system 13, the side scattered light is incident on the beam splitter 17 by the detection optical system 13.
- FIG. 3 is a diagram for explaining the arrangement of the flow cell 2, the detection optical system 13, and the beam splitter 17 in FIG. Specifically, as shown in FIG. 3, the detection optical system 13 emits along the traveling direction of the fluid (that is, the particles) in the detection region among the scattered light emitted by the particles and the fluid in the flow path 2 a. The scattered light is incident on the beam splitter 17.
- the detection optical system 13 emits along the traveling direction of the fluid (that is, the particles) in the detection region among the scattered light emitted by the particles and the fluid in the flow path 2 a. The scattered light is incident on the beam splitter 17.
- the traveling direction (X direction) of the fluid (that is, the particles) and the optical axis of the detection optical system 13 are the same direction, and the center of the detection region Scattered light within a predetermined solid angle enters the beam splitter 17.
- the particles in the detection region are detected.
- the change in the optical path length which is the distance between the particle and the beam splitter 17 becomes larger than when the scattered light of the particle is detected in another direction (other than the X direction). This point will be described later.
- the reference light branched by the beam splitter 11 enters the attenuator 14.
- the attenuator 14 attenuates the light intensity at a predetermined rate.
- an ND (NeutralutDensity) filter is used for the attenuator 14.
- the mirror 15 reflects the reference light emitted from the attenuator 14 and causes the reference light to enter the beam expander 16.
- the beam splitter 11 and the attenuator 14 make the intensity of the reference light about 1 / 10,000 of the intensity of the light emitted from the light source 1.
- the intensity of the reference light incident on the beam splitter 17 is set according to the particle size of the particles to be counted, scattered light intensity, and the like, and the attenuation factor of the attenuator 14 is set so as to realize the intensity of the reference light. Is done.
- the beam expander 16 expands the beam diameter of the reference light to a predetermined diameter, and converts the reference light whose beam diameter has been increased into a substantially parallel light to a predetermined incident surface of the beam splitter 17 (separate from the scattered light incident surface). Incident on the incident surface.
- the detection optical system 13, the mirror 15, and the beam expander 16 make the wavefront shape of the scattered light and the wavefront shape of the reference light substantially coincide with each other in the beam splitter 17.
- the detection optical system 13 and the beam expander 16 emit scattered light and reference light as substantially parallel light, respectively.
- the wavefront shapes of the scattered light and the reference light may be curved surfaces.
- the detection optical system 13, the mirror 15, and the beam expander 16 are configured so that the polarization angles coincide with each other in the beam splitter 17.
- the attenuator 14 in order to further increase the degree of interference, in the optical path of the reference light, the attenuator 14, the mirror 15, the beam expander 16, and the like that control the intensity, polarization angle, and wavefront shape of the reference light Is installed.
- the beam splitter 17 spatially superimposes the incident scattered light and the incident reference light, and causes interference to strengthen or weaken each other.
- the beam splitter 17 is provided separately from the beam splitter 11.
- the phase difference between the scattered light and the reference light changes according to the change in the optical path length accompanying the movement of the particles in the detection region, and the intensity of the interference light by the light transmitted or reflected by the beam splitter 17 itself. Changes.
- the optical path length of the scattered light accompanying the movement of the particles in the detection region is large and changes quickly. The speed of intensity change of the interference light is also increased.
- the intensity of the interference light changes at a period (that is, frequency) corresponding to the velocity in the traveling direction of the fluid (that is, particles) in the detection region.
- a period that is, frequency
- the scattered light from the particles is not incident
- light (transmitted component and reflected component) obtained by branching the scattered light from the fluid and the reference light is emitted from the beam splitter 17 by interference.
- the change in the interference light is smaller than that due to the particles.
- the condensing part 18a condenses the light radiate
- the condensing part 18b condenses the light radiate
- a condensing lens is used for the condensing units 18a and 18b.
- FIG. 4 is a diagram for explaining the branching of light in the beam splitter 17 in FIG.
- the optical axis of the reflection component S ⁇ b> 1 of the scattered light S and the optical axis of the transmission component R ⁇ b> 2 of the reference light R match, and the optical axis of the transmission component S ⁇ b> 2 of the scattered light S and the reference light R.
- the scattered light S and the reference light R are incident so that the optical axes of the reflection components R1 coincide.
- Light is emitted.
- the first interference light and the second interference light are incident on the light receiving elements 21a and 21b of the detection unit 4 via the light collection units 18a and 18b, respectively.
- the scattered light S and the reference light R are incident on the light splitting surface of the beam splitter 17 at approximately 45 degrees, and the transmitted components S2 and R2 are in phase with the scattered light S and the reference light R, respectively. Since the phases of the reflection components S1 and R1 are respectively delayed by 90 degrees with respect to the scattered light S and the reference light R, the first interference light and the second interference light are out of phase with each other.
- the ratio of the transmission component and the reflection component in the beam splitter 17 is preferably 50:50, but may be an unequal ratio such as 60:40.
- the ratio of the transmitted component and the reflected component in the beam splitter 17 is unequal, the transmitted component of the reference light in the electrical signal V1 and the reflected component of the reference light in the electrical signal V2 are the same according to the ratio.
- the gains of the amplifiers 22a and 22b are set.
- the beam damper 19 absorbs light that has passed through the flow cell 2. Thereby, the influence on the optical system 3 by the irregular reflection of the light which passed the flow cell 2, leakage, etc. can be suppressed.
- the detection unit 4 receives the interference light obtained by the beam splitter 17 by the light receiving elements 21a and 21b, and generates a detection signal Vo corresponding to the difference between the interference light.
- the detection unit 4 includes light receiving elements 21 a and 21 b, amplifiers 22 a and 22 b, and a difference calculation unit 23.
- the light receiving elements 21a and 21b are photodetectors such as photodiodes and phototransistors, and each output an electrical signal corresponding to incident light.
- the amplifiers 22a and 22b amplify the electric signals output from the light receiving elements 21a and 21b with a predetermined gain.
- the difference calculation unit 23 calculates a difference between the electric signal V1 corresponding to the first interference light obtained by the light receiving element 21a and the electric signal V2 corresponding to the second interference light obtained by the light receiving element 22a, and outputs the difference as a detection signal Vo. To do.
- the gains of the amplifiers 22a and 22b are set so that the voltage of the electrical signal V1 and the voltage of the electrical signal V2 are the same in a state that does not include the scattered light component due to particles (scattered light component due to fluid and reference light component). It has been adjusted. Instead, only one of the amplifiers 22a and 22b may be provided, and the gain of the amplifier may be adjusted so that both are the same. If the voltage of the electrical signal of the light receiving element 21a and the voltage of the electrical signal of the light receiving element 22a are the same, the amplifiers 22a and 22b may not be provided.
- FIG. 5 is a timing chart for explaining a detection signal obtained by the detection unit 4 in FIG.
- the optical path length from the particle to the light splitting surface of the beam splitter 17 changes in accordance with the movement of the particle in the detection region in the traveling direction (X direction), and the phase difference between the scattered light from the particle and the reference light Changes, and the intensity (amplitude) of the interference light changes between strengthening and weakening.
- the electric signal V1 varies positively or negatively according to the degree of interference with reference to the voltage V1o in the absence of particles during the period in which the particles pass through the detection region.
- the voltage is V1o.
- the electric signal V2 varies positively and negatively according to the degree of interference with reference to the voltage V2o in the absence of particles during that period, and becomes the voltage V2o during other periods.
- the AC components of the electrical signals V1 and V2 during that period are in opposite phases.
- the detection signal Vo obtained by the difference calculation unit 23 has particles as shown in FIG.
- the AC component has an AC component having a larger amplitude (about twice) than the AC component caused by interference in each of the electric signals V1 and V2, and the voltage is substantially zero in other periods. It becomes.
- scattered light emitted along the fluid traveling direction (X direction) in the detection region is detected so that the change in the optical path amount becomes large when the particles pass through the detection region. It was decided.
- the moving distance of the particle becomes a change in the optical path length between the particle and the light splitting surface of the beam splitter 17, so that the scattered light of the particle is transmitted in another direction (X).
- the number of changes in interference increases (that is, the phase rotation of the interference light increases) rather than detection in a direction other than the direction.
- the detection direction of the scattered light is not limited as long as the scattered light can be detected.
- scattered light (background light) from the liquid which is a fluid medium
- background light background light
- the AC component caused by background light interference becomes smaller.
- the intensity of scattered light due to Rayleigh scattering is proportional to the sixth power of the particle diameter.
- the intensity of the interference light between the scattered light and the reference light is proportional to the cube of the particle diameter. Therefore, when detecting the interference light, the decrease in the intensity when the particle size is reduced is smaller than when the scattered light is directly detected.
- the difference between the maximum value and the minimum value of the interference light intensity between the scattered light and the reference light (difference in the interference light intensity when the phase difference between the scattered light and the reference light is 0 and 180 degrees). Is proportional to the product of the electric field intensity Er of the reference light and the electric field intensity Es of the scattered light. Therefore, by increasing the intensity of the reference light, sufficiently strong interference light can be obtained, and consequently a detection signal having a sufficiently large amplitude can be obtained. As the intensity of the reference light increases, the intensity of the interference light increases. However, the detection signal can be processed satisfactorily according to the dynamic ranges of the detection unit 4, the filter 5, and the counting unit 6.
- the electric field intensity Es of the scattered light is 5.8 ⁇ 10 ⁇ 3 V / m.
- the electric field intensity Er of the reference light is 2.4 V / m. If the scattered light and the reference light interfere with each other in the entire wavefront, the above-described difference in interference light intensity is 1.2 ⁇ 10 ⁇ 2 ⁇ W, which is about 1600 times the scattered light intensity, and the particle diameter is 70 nm. It is amplified to the same level as the scattered light intensity of the particles.
- the filter 5 performs a filtering process on the detection signal Vo generated by the detection unit 4.
- the filter 5 passes a frequency component (that is, a frequency component of interference light) corresponding to the fluid velocity (that is, the moving velocity of particles) in the flow path 2a, and a frequency other than the frequency component corresponding to the traveling velocity of the fluid.
- Filter processing for attenuating components is performed on the detection signal Vo. Thereby, the noise component in the detection signal Vo is attenuated, and the S / N ratio of the detection signal Vo becomes higher.
- the passband frequency is specified in advance from the moving speed of the particles, the wavelength of the measurement light (that is, the wavelength of the light source 1), and the like.
- the filter 5 is a band pass filter. Note that a low-pass filter may be used when the noise frequency is higher than the interference light frequency, and a high-pass filter may be used when the noise frequency is lower than the interference light frequency.
- the counting unit 6 counts particles based on the detection signal Vo.
- the counting unit 6 counts particles based on the detection signal Vo after the filter processing by the filter 5. For example, when the counting unit 6 detects the alternating current component (that is, the frequency component of interference light) that is continuous for the above-described period in the detection signal Vo, the counting unit 6 compares the amplitude with a predetermined threshold value determined for each particle size. Each particle is counted separately.
- the alternating current component that is, the frequency component of interference light
- the light source 1 emits laser light, and the beam splitter 11 branches the laser light into measurement light and reference light.
- the reference light is attenuated by the attenuator 14, passes through the mirror 15 and the beam expander 16, and enters the beam splitter 17 as substantially parallel light.
- the measurement light is incident on the detection region in the flow cell 2 by the irradiation optical system 12.
- the particles pass through the detection region, scattered light from the particles is generated during the period of passing through the detection region.
- the detection optical system 13 causes the scattered light emitted along the traveling direction (X direction) of the fluid in the flow path 2a of the flow cell 2 to enter the beam splitter 17 as substantially parallel light.
- the reference light and the scattered light from the particles are incident on the beam splitter 17, and both interference lights are emitted from the beam splitter 17.
- Interference light emitted from the beam splitter 17 while the particles pass through the detection region is received by the light receiving elements 21a and 21b, respectively, and an electric signal corresponding to the intensity of the interference light is output from the detection unit 4 as a detection signal Vo.
- the detection signal Vo is generated based on the difference between the first interference light and the second interference light, which are in opposite phases to each other. Therefore, the detection signal Vo is approximately twice as large as the electrical signals V1 and V2. A detection signal Vo of an alternating current component of amplitude is obtained.
- the filter 5 performs the above-described filter processing on the detection signal, and the counting unit 6 counts particles based on the detection signal after the filter processing.
- the irradiation optical system 12 emits one of a plurality of lights obtained by branching the light from the light source 1 from a direction different from the direction in which the fluid flows.
- the detection region is formed by irradiating the fluid in the flow path 2a.
- the detection optical system 13 causes the scattered light in the direction different from the optical axis of the irradiation optical system 12 out of the scattered light from the particles included in the fluid in the detection region to enter the beam splitter 17.
- the beam expander 16 causes another light of the plurality of lights to enter the beam splitter 17 as reference light.
- the detection unit 4 receives the interference light between the scattered light and the reference light obtained by the beam splitter 17 with a light receiving element, generates a detection signal corresponding to the interference light, and the counting unit 6 is based on the detection signal. Count the particles.
- the passage of the particle is detected based on the interference light caused by the passage of the particle in the detection region. Therefore, it is possible to count the small particle diameter in the fluid with a better S / N ratio than in the case of detecting scattered light.
- the first interference light and the second interference light are received as the interference light between the scattered light from the particles and the reference light, and the difference between the electric signals V1 and V2 is set as the detection signal Vo.
- the electric signal of one of the first interference light and the second interference light is used as the detection signal Vo. Even in this case, since the detection signal Vo includes an AC component caused by the interference light between the scattered light from the particles and the reference light, the particles can be similarly counted. In this case, only one light receiving element is required.
- the beam expander 16 is provided in the optical path of the reference light, but instead or in addition, a beam expander may be provided before the beam splitter 11. Good.
- a beam expander may be provided before the beam splitter 11. Good.
- one mirror 15 is used as shown in FIG. 1, but the direction of the optical path can be adjusted three-dimensionally using three mirrors. Good.
- the beam splitter 17 is used to superimpose the scattered light from the particles and the reference light, but a polarizing prism may be used instead.
- the filter 5 may be omitted. In this case, the detection signal Vo is directly input to the counting unit 6.
- the light source 1 is a light source that emits laser light that is highly coherent in a single mode. Instead, a light source that emits laser light that is relatively low coherent in a multimode is used. May be used. However, it is preferable to use a light source having an energy distribution that causes interference between the scattered light from the particles and the reference light at any position in the detection region.
- the filter 5 and the counting unit 6 may be analog circuits or digital circuits.
- analog-digital conversion is performed on the detection signal Vo before the filter 5.
- a so-called Mach-Zehnder type interference optical system in which beam splitting and light superposition are performed by different beam splitters 11 and 17 is employed.
- a Michelson type or other interference optical system may be employed.
- the particle counter according to the first and second embodiments is a submerged particle counter
- the particle counter according to the first and second embodiments may be applied to an air particle counter.
- the present invention is applicable to, for example, a particle counter for chemicals.
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Abstract
Description
光および第2干渉光を受光し、第1干渉光に対応する電気信号および第2干渉光に対応する電気信号の差分を検出信号とする。
4 検出部
5 フィルタ
6 計数部
11 ビームスプリッタ(光分岐部の一例)
12 照射光学系
13 検出光学系
16 ビームエキスパンダ(参照光学系の一例)
17 ビームスプリッタ(光重畳部の一例)
21a,21b 受光素子
Claims (5)
- 光を出射する光源と、
2つの光を空間的に重畳する光重畳部と、
前記光源からの光を分岐して得られる複数の光のうちの1つの光を流路内を流れる流体に照射して検出領域を形成する照射光学系と、
前記検出領域内の前記流体に含まれる粒子からの散乱光のうち、前記照射光学系の光軸とは異なる方向の散乱光を、前記光重畳部に入射させる検出光学系と、
前記複数の光のうちの別の1つの光を参照光として前記光重畳部に入射させる参照光学系と、
前記光重畳部によって得られる、前記散乱光と前記参照光との干渉光を受光素子で受光し、前記干渉光に対応する検出信号を生成する検出部と、
前記検出信号に基づいて前記粒子の計数を行う計数部と、
を備え、
前記光重畳部は、ビームスプリッタであり、前記散乱光の透過成分と前記参照光の反射成分とによる第1干渉光と、前記散乱光の反射成分と前記参照光の透過成分とによる第2干渉光とを生成し、
前記検出部は、2つの受光素子で前記第1干渉光および前記第2干渉光を受光し、前記第1干渉光に対応する電気信号および前記第2干渉光に対応する電気信号の差分を前記検出信号とすること、
を特徴とするパーティクルカウンタ。 - 前記検出光学系は、前記流路内の前記粒子から発する散乱光のうち、前記検出領域での前記流体の進行方向へ沿って発する散乱光を前記光重畳部に入射させることを特徴とする請求項1記載のパーティクルカウンタ。
- 前記検出部により生成された前記検出信号に対してフィルタ処理を行うフィルタをさらに備え、
前記フィルタは、前記流体の進行速度に対応する周波数成分を通過させ、前記流体の進行速度に対応する周波数成分以外の周波数成分を減衰させるフィルタ処理を前記検出信号に対して行い、
前記計数部は、前記フィルタによるフィルタ処理後の前記検出信号に基づいて前記粒子の計数を行うこと、
を特徴とする請求項1または請求項2記載のパーティクルカウンタ。 - 前記検出光学系および前記参照光学系は、前記散乱光の波面形状と前記参照光の波面形状が略一致するように前記散乱光および前記参照光を出射することを特徴とする請求項1から請求項3のうちのいずれか1項記載のパーティクルカウンタ。
- 前記光重畳部とは別に、前記光源からの光を前記複数の光に分岐する光分岐部を備えることを特徴とする請求項1から請求項4のうちのいずれか1項記載のパーティクルカウンタ。
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106644867A (zh) * | 2016-12-30 | 2017-05-10 | 聚光科技(杭州)股份有限公司 | 气体中颗粒物的检测装置及方法 |
KR20200002817A (ko) * | 2017-04-14 | 2020-01-08 | 리온 가부시키가이샤 | 입자 측정 장치 및 입자 측정 방법 |
CN110914665A (zh) * | 2017-05-12 | 2020-03-24 | 通快光子元件有限公司 | 自混合干涉颗粒检测期间抑制假阳性信号的方法 |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5859154B1 (ja) * | 2015-03-06 | 2016-02-10 | リオン株式会社 | パーティクルカウンタ |
JP6413006B1 (ja) | 2017-11-28 | 2018-10-24 | リオン株式会社 | パーティクルカウンタ |
JP7071849B2 (ja) * | 2018-03-09 | 2022-05-19 | リオン株式会社 | パーティクルカウンタ |
WO2020207908A1 (en) * | 2019-04-11 | 2020-10-15 | Koninklijke Philips N.V. | A particle sensing system for example for use in a pollution mask |
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EP4053535A1 (en) * | 2021-03-01 | 2022-09-07 | Q.ant GmbH | Particle sensor, device and method for detecting particles |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0458137A (ja) * | 1990-06-27 | 1992-02-25 | Hitachi Electron Eng Co Ltd | ヘテロダイン微粒子検出器の光学系 |
JPH06331529A (ja) * | 1993-05-19 | 1994-12-02 | Toshiba Corp | 微粒子検出装置 |
JP2009030988A (ja) * | 2007-07-24 | 2009-02-12 | Rion Co Ltd | 粒子計数装置 |
JP2014044095A (ja) * | 2012-08-24 | 2014-03-13 | Ushio Inc | 三次元位置測定方法、速度測定方法、三次元位置測定装置及び速度測定装置 |
JP2014092425A (ja) * | 2012-11-02 | 2014-05-19 | Canon Inc | 光干渉断層撮像装置及び光干渉断層撮像方法 |
JP5859154B1 (ja) * | 2015-03-06 | 2016-02-10 | リオン株式会社 | パーティクルカウンタ |
Family Cites Families (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5134177B1 (ja) | 1963-08-01 | 1976-09-24 | ||
JPS62291547A (ja) | 1986-06-11 | 1987-12-18 | Olympus Optical Co Ltd | 物質の濃度測定方法 |
JPH01245132A (ja) * | 1988-03-28 | 1989-09-29 | Hitachi Electron Eng Co Ltd | 微粒子検出方式 |
US5061070A (en) * | 1988-04-22 | 1991-10-29 | International Business Machines Corporation | Particulate inspection of fluids using interferometric light measurements |
JPH06213795A (ja) * | 1993-01-19 | 1994-08-05 | Mitsubishi Electric Corp | 浮遊粒子計測装置 |
JPH11118699A (ja) * | 1997-10-20 | 1999-04-30 | Hitachi Ltd | 据付型濁度計の校正方法 |
JP3771417B2 (ja) * | 2000-03-21 | 2006-04-26 | 独立行政法人科学技術振興機構 | 微粒子測定方法およびその装置 |
EP1277040A2 (en) | 2000-04-28 | 2003-01-22 | Massachusetts Institute Of Technology | Methods and systems using field-based light scattering spectroscopy |
US9297737B2 (en) * | 2004-03-06 | 2016-03-29 | Michael Trainer | Methods and apparatus for determining characteristics of particles |
JP2007071794A (ja) * | 2005-09-09 | 2007-03-22 | Rion Co Ltd | 粒子検出器 |
JP2007333409A (ja) * | 2006-06-12 | 2007-12-27 | Horiba Ltd | 浮遊粒子測定装置 |
JP5325679B2 (ja) * | 2009-07-03 | 2013-10-23 | 富士フイルム株式会社 | 低コヒーレンス光源を用いた動的光散乱測定装置及び光散乱強度測定方法 |
CN102003936B (zh) * | 2010-09-14 | 2012-01-04 | 浙江大学 | 同时测量液滴位置、粒径和复折射率的方法和装置 |
JP5438198B1 (ja) * | 2012-11-05 | 2014-03-12 | リオン株式会社 | 光散乱式粒子計数器 |
JP5754067B2 (ja) * | 2012-11-06 | 2015-07-22 | パルステック工業株式会社 | 動的光散乱測定装置および動的光散乱測定方法 |
CN103674791A (zh) * | 2013-12-16 | 2014-03-26 | 天津大学 | 一种基于双光束照射的干涉粒子成像测量方法 |
CN203705307U (zh) * | 2013-12-16 | 2014-07-09 | 天津大学 | 基于双光束相向照射的干涉粒子成像测量装置 |
CN104020085B (zh) * | 2014-06-17 | 2016-07-06 | 大连理工大学 | 一种不受背景影响的微纳粒子的光学探测与显微成像方法 |
CN104297115B (zh) * | 2014-09-26 | 2017-02-08 | 深圳职业技术学院 | 一种大气颗粒物pm2.5数密度检测的方法 |
-
2015
- 2015-03-06 JP JP2015045175A patent/JP5859154B1/ja active Active
-
2016
- 2016-03-04 WO PCT/JP2016/056787 patent/WO2016143696A1/ja active Application Filing
- 2016-03-04 US US15/555,376 patent/US10054529B2/en active Active
- 2016-03-04 CN CN201680013946.9A patent/CN107430056B/zh active Active
- 2016-03-04 KR KR1020177026530A patent/KR101824900B1/ko active IP Right Grant
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0458137A (ja) * | 1990-06-27 | 1992-02-25 | Hitachi Electron Eng Co Ltd | ヘテロダイン微粒子検出器の光学系 |
JPH06331529A (ja) * | 1993-05-19 | 1994-12-02 | Toshiba Corp | 微粒子検出装置 |
JP2009030988A (ja) * | 2007-07-24 | 2009-02-12 | Rion Co Ltd | 粒子計数装置 |
JP2014044095A (ja) * | 2012-08-24 | 2014-03-13 | Ushio Inc | 三次元位置測定方法、速度測定方法、三次元位置測定装置及び速度測定装置 |
JP2014092425A (ja) * | 2012-11-02 | 2014-05-19 | Canon Inc | 光干渉断層撮像装置及び光干渉断層撮像方法 |
JP5859154B1 (ja) * | 2015-03-06 | 2016-02-10 | リオン株式会社 | パーティクルカウンタ |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106644867A (zh) * | 2016-12-30 | 2017-05-10 | 聚光科技(杭州)股份有限公司 | 气体中颗粒物的检测装置及方法 |
CN106644867B (zh) * | 2016-12-30 | 2023-08-29 | 聚光科技(杭州)股份有限公司 | 气体中颗粒物的检测装置及方法 |
KR20200002817A (ko) * | 2017-04-14 | 2020-01-08 | 리온 가부시키가이샤 | 입자 측정 장치 및 입자 측정 방법 |
EP3611492A4 (en) * | 2017-04-14 | 2020-05-13 | Rion Co., Ltd. | PARTICLE MEASURING DEVICE AND PARTICLE MEASURING METHOD |
US10837890B2 (en) | 2017-04-14 | 2020-11-17 | Rion Co., Ltd. | Particle measuring device and particle measuring method |
KR102482542B1 (ko) | 2017-04-14 | 2022-12-28 | 리온 가부시키가이샤 | 입자 측정 장치 및 입자 측정 방법 |
CN110914665A (zh) * | 2017-05-12 | 2020-03-24 | 通快光子元件有限公司 | 自混合干涉颗粒检测期间抑制假阳性信号的方法 |
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