JPS61288139A - Fine particle detecting device - Google Patents

Abstract

PURPOSE:To reduce a particle size which can be detected without decreasing the capacity of particulate containing liquid which can be inspected within a constant time and a decrease in particle size resolution by providing a beam polarizing part which scans the liquid to be measured linearly and repeatedly with beam light. CONSTITUTION:A detecting device consists of a beam light irradiating mechanism 19 which irradiates the particulate containing liquid 2 to be measured with the beam light 6 and a photodetection mechanism 8 which photodetects scattered light emitted by particulates by the irradiation of the beam light and outputs a signal corresponding to the scattered light. Then, the irradiating mechanism 19 is provided with a beam light deflecting part 18 to scan the liquid to be measured with the beam light repeatedly. Consequently, the uniform intensity distribution area of the beam light at the part of the object liquid irradiated with the beam light is expanded in the scanning direction of the beam light, thereby eliminating the influence of the intensity distribution shape of the beam light upon the particle size resolution of the detecting device.

Description

[Detailed description of the invention] [Invention +7] Technical field to which the present invention belongs] The present invention irradiates a flowing fluid containing fine particles at a dilute concentration with light, and detects direct scattered light or fluorescent scattered light of the light caused by the sound of the fine particles. Then, information on the number and size of the particles, and information on the properties of the cells (if the particles are cells), etc. can be obtained.
This relates to an apparatus configuration that can reduce the detectable particle size without causing a decrease in volume or a drop in particle size resolution.

[Prior art and its problems]

In the manufacturing process of semiconductors and pharmaceuticals, environmental air σ) is exposed to inspect the cleanliness, ultrapure water, quality of chemicals, etc.

In addition, in research fields such as medicine and biology, particle detection equipment is required to detect particles such as dust and cells in order to inspect the state of cells. The particle size is usually several μm or less for concentrated fluid samples and 1 to 10 particles/wtt for gas samples.728.
However, in recent years, there has been a demand for particulate detectors tC that can detect particle sizes of 0.1 μm or less.

Figure 8 is a configuration diagram of a conventional liquid particle detection device.
In ζ, 1 is a 70-cell with a transparent side wall, which has a rectangular cross section and allows the measurement liquid 2 containing fine particles to flow in a direction perpendicular to the paper surface, and 3 is a light emitting cell that emits a parallel light beam 4. This is a beam light irradiation mechanism consisting of a device 5 and a focusing lens 7 that focuses the light beam 4 into a beam 6j. The beam light 6 is irradiated with L so that the optical axis of the beam light 6 coincides with the illustrated axis B1-Bt.@B+ By is the axis C, -C, and the illustrated The three spatial axes that are perpendicular to the plane of the paper and perpendicular to t are the axes assumed in the plane of Figure 1, and 0 is the axis inside the flow cell 1 +
C is the intersection of the three axes σ) set. 8 is a condenser lens 9 that condenses the scattered light emitted from the fine particles σ in the liquid 2 in the vicinity of the intersection 0 when the liquid 2 is irradiated with the beam light 6, and the lens 9I condenses the condensed light. A photoelectric converter 10 that converts the received light into an electrical signal 103 according to the light intensity ζ and outputs it, and a photoelectric converter 10 that is interposed between the lens 9 and the converter 10 and limits the angle of incidence of the light that enters the converter 9. The light receiving mechanism 8 includes an opening member 11 provided with a circular through hole 11a as shown in FIG.

Reference numeral 12 denotes a beam block provided to prevent the beam light 6 transmitted through the 70-cell 1 from entering the light receiving mechanism 8 as stray light, and the block 12 is configured to absorb the beam light 6. . Reference numeral 14 denotes a signal processing unit which performs predetermined signal processing on the electric signal Loafζ and displays the state of the particles such as the number of particles σ, particle size distribution, and properties.

Fig. 8) Light receiving mechanism 8 in the detection device shown in Fig. 8)
σ) The operation will be explained using FIG. Namely.

FIG. 9 is an enlarged perspective view of the main part O) in FIG.

and axes C and -C, which form three orthogonal axes; axes A and -A are also the longitudinal direction θ of the flow cell II]
It is aligned with the axis. P is parallel to axis A, -A2 +
Measuring liquid 2σ] This is an arrow indicating the flow direction.

Reference numeral 13 denotes a three-dimensional viewing area (light receiving mechanism 80) formed near the intersection 0. The viewing area 13 is centered on the intersection 0 and has axes C, -, since the light receiving mechanism 8 is 1 cm long as described above.
There is a spindle shape with C as the axis.

Since the area 13 is the field of view of the light receiving mechanism (8σ), the area 13
Of the light emitted from the light σ), only the light captured by the light receiver @ 8 tc is photoelectrically converted by the mechanism 8. FIG. 9■ In this case, the main part is constructed so that all of the viewing area 13 exists within the beam light 6, so when the particles are transported by the measurement liquid 2I and pass through the area 13, they are pulsed. Scattered light is generated, and therefore, the scattered light enters the photoelectric converter 10 and the photoelectrically converted signal tOa also becomes a pulse. The number and size of particles passing through the viewing area 13 can be detected by the number and magnitude of pulses formed by the powder signal 1. The signal processing section 14 in FIG. 8 is configured to perform such signal processing.

In FIG. 8), particle detection is performed according to the above-mentioned procedure σ), but if the amount of light received by the light receiving mechanism 8 is small, accurate particle detection becomes impossible. Therefore, in order to increase the amount of scattered light, the light beam 6 is narrowly focused to increase the light intensity.
The diameter at tC near the intersection 0 is several hundred to several tens of μm. FIG. 80] The focusing lens 7 is provided for this reason.

In Fig. 8, the visual field area 13 is disturbed as described above.
The number and diameter of particles σ) passing through the area 13) are detected, but if the intensity distribution of the beam light 60 in the region 13) ζ is non-uniform, a particle detection error will occur as explained below. In other words, FIG. 10 is an explanatory diagram explaining the reason for the occurrence of such a detection error, and FIG. 10 (2) shows the area 13 in FIG.
This figure corresponds to a figure whose vicinity is cut along a plane formed by axes A, -A, and axis C1-C1. 15 to Figure 10
．． Reference numeral 16 denotes a viewing area and a beam light corresponding to the area 13 and the beam light 6 in FIG. 17
a.

17b is transported by the measuring liquid 2) and moves in the P direction on the paper surface of the figure so as to cut through the region 15. They are two spherical σ] fine particles with the same particle size.

When the fine particles 17a and L7b move as described above in Figure 1O, the intensity distribution on the paper surface of the figure in the beam light 16 reaches the maximum light intensity at one point OI, as shown in Figure 10■. If the value is set in a bell-like manner, the paths taken by the fine particles 17a and 17b through the region 15 may become too hot, and the scattered light from the beam light t61c may not be generated.
Alternatively, scattered light having different intensities may be generated for the fine particles 17a+17biζ having the same size. Therefore, in the former case, a detection error occurs depending on the number of particles, and in the latter case, a detection error occurs depending on the particle size of the particles. In the above-mentioned particle detection device, a laser beam is usually used as the beam light in order to increase the intensity of the beam light that irradiates the measurement liquid to detect particles with a particle size as small as possible. In such a laser beam, the light intensity distribution is 1C as shown in FIG.

For this reason, conventionally, the light intensity is almost uniform on the light intensity distribution curve shown in FIG. Axis A shown in Figure 10^,
- A, a method of squeezing the liquid so that it flows only in the vicinity, or a method of narrowing the liquid so that it flows only in the vicinity. However, in a particle detection device that adopts the former method, the 1ζ beam light is narrowed down to increase the light intensity in order to reduce the particle size of detectable particles.

Measured liquid portion σ) Light intensity distribution σ] As the degree of non-uniformity increases, the error in detecting the particle size increases.In other words, the resolution of the detection device for the particle size +C deteriorates, and this σ
] In order to prevent deterioration of the particle size resolution, the liquid to be measured is roughly squeezed so that the liquid exists only in the part where the beam light intensity distribution is uniform. ] There is a problem that ik decreases. In addition, in a particle detection device that adopts the latter method, when the beam light 6 is narrowed down to reduce the detectable particle size, the viewing area 13 of the light receiving mechanism 8 is If the urn is placed over the entire area, then the urn ζ is
There is a problem that the particle size resolution decreases for the same reason as mentioned above, and in order to prevent such a decrease in resolution, the through hole tta of the aperture member is
As the amount of light passing through the through hole decreases, the amount of scattered light incident on the photoelectric converter 10) becomes smaller than the amount of light beam 6).
As a result, the increase in the light intensity does not increase even if the light intensity of be.

[Invention θ] Purpose]

The present invention is directed to the above-mentioned conventional particulate detection device 1 (
It is an object of the present invention to provide a particulate detection device that can reduce the detectable particle size without causing a decrease in the volume of a particulate-containing fluid that can be inspected for a certain period of time or a decrease in particle size resolution. shall be.

[Key points of the invention]

In order to achieve the above-mentioned objects, the present invention provides a beam light irradiation mechanism that irradiates a particle-containing measurement fluid with a beam light, and a beam light irradiation mechanism that receives the scattered light emitted from the particles by the beam light irradiation and receives the scattered light)C. In a particle detection device that detects particles based on the output signal of the light receiving mechanism, the beam light irradiation mechanism repeatedly scans the fluid to be measured with the beam light in a straight line. This structure is provided with a deflection section, and as a result, the area where the intensity distribution of the beam light is uniform in the measurement liquid portion irradiated by the beam light tube is substantially uniform in the scanning direction of the beam light. The particulate-containing measuring fluid σ] which can be inspected by self-inspection for a certain period of time is It is now possible to obtain a particle detection device that can reduce the detectable particle size σ) without causing a decrease in diameter resolution.

[Embodiments of the invention]

FIG. 1 is a block diagram of a first embodiment of the present invention.

The main difference from the diagram shown in FIG.
ζ Since the beam polarization unit 18 that repeatedly scans is provided, and the signal processing unit 31 that performs signal processing different from the signal processing unit 14 in FIG. The device 5 emits the laser beam as a parallel beam 4.
It consists of an e-Ne laser light generator. 19 is the excavator 5 and the focusing lens 7
1 with a beam light irradiation mechanism consisting of
When the light emitter 5 is a high output laser generator or when the He-C
In the case of a short wavelength laser generator such as a laser generator, there is no need to use the focusing lens 7 because the laser beam emitted from the short wavelength laser generator is strong. There is also. The beam deflector 18 is constructed as shown in FIG. 1C. In other words, Figure 2 is a configuration diagram of the main parts in Figure 1, and the number in Figure 2 is 2.
0 is the state in which the laser beam 4 is incident on the reflecting surface at point σ) Q - ζ, and the imaging magnetic field by the electromagnet 21) is a reflecting mirror whose inclination is changed within the range of angle 2θO] by repeated vibrations. It is. Since the beam light deflecting section 18 is composed of the reflecting mirror 20 and the electromagnet 21 configured in this way, the beam light 6 emitted from the deflecting section 18 also oscillates within the range of angle 2θ, as shown in the figure. The direction changes approximately.

Therefore, in FIG. 1, the measuring liquid 2 is scanned in a straight line by the light beam 6 whose direction changes as described above, and in this case, the light beam 6 rotates around the point Q. The +C'JJ section is constructed so that the scanning surface formed by the moving heat ζ coincides with the paper surface EC of FIG. As is clear from FIG. 2, the light beam 6 is on the axis B.

There is an angle θ on both sides of -B.

Figure 3 is an explanatory diagram of the operation of the particle detector σ shown in Figures 1 and 2 (1C); )l corresponding first
Figure σ) is a side sectional view. In FIG. 3, E and F are the intersections of the optical axis of the beam 6 and the axes C, -C when the beam 6 reaches the outermost point, and L is the point Q.

0, t is the distance between points E and F, d is the beam light 6
When the optical axis of passes through point E or F, aj Al-A,
The diameter of the circular spot 22 or 23[sigma] due to the beam light 6I formed on the plane formed by the axes C and -C, respectively. As described above, since the beam light 6 changes dynamically within the range of angle 2θ, 4IIAI
In the plane E formed by At and the axes C, -C,
Region 2 consisting of a rectangular strip 24a having a length t and a width d and semicircular portions 24b continuous to each end of the strip 24a.
4 is periodically and repeatedly irradiated with beam light 6-ζ. In other words, the area 24 is an area irradiated by the beam light 6, and in this case, the viewing area 13 is arranged EC so as to include the irradiation area 24. Actually, the diameter of the circular spot of the beam 6I whose optical axis passes through the point 0, thus forming the region 24) is smaller than d, but L
=40+a, θ=2° and t=2
．． 8), the band-shaped portion 24a may be substantially rectangular. In FIG. 3, the irradiation area 24 and viewing area 13 are arranged as described above, so that
Due to the scattered light caused by the particles 1<II' passing through the irradiation area 24, an electric signal 10a as shown in FIG. 4 is output from the photoelectric converter 10 in FIG.

FIG. 4 is an explanatory diagram corresponding to FIG. 3 0, and in the figure, the visual field area 13 in FIG. 3 0 is omitted for convenience. In Figure 4, 17 is a fine particle that moves at a constant speed in the P direction parallel to the axis A1-A and blows out the region 24;
25 is a light intensity distribution characteristic line of the beam spot 22 along the axis C1-C,l, and 26 is a light intensity distribution characteristic line of the beam spot 23 corresponding to the characteristic line 25+this. The characteristic lines 25 and 26 are hanging chain curves having the same shape, and as a result, in the irradiation area 24, the distance between points E and F is σ) axis C, -C, upper σ]
Part σ) Light intensity distribution or maximum sound. Naoko σ) case t
The main part of the canter is constructed so that >d. In FIG. 4, if the deflection speed of the beam light 6σ in FIG. 3 is set to be considerably faster than the moving speed F of the particles 170, the particles 17 will move through the irradiation area 24, resulting in a series of movements as shown in the figure. σ) An electrical signal 10a consisting of a pulse train is generated, and the envelope 27 of the individual pulses constituting the σ) signal tOa has a bell-like shape corresponding to the characteristic line 25 or 26.

Therefore, the pulse train σ having such an envelope shape
) By counting the number of particles 17 passing through the region 24, the number of particles 17 can be detected, and by measuring the maximum value of the envelope 27 tC, the particle size of the particles 17 can be detected. FIG. 1 σ] Signal processing section 31
is configured to perform signal processing such as [signal 10al versus deko σ]. Fig. 1 σ) In the example, d = 0.
1 [throat], and the vibration frequency of the beam light 6 is set to 20 (KHz).

When the moving speed of the fine particles 17 is 50 (rm/S), the time for the fine particles 17 to pass through the region 24 is 0.115
0=2XlOCs ), and as a result, the number of pulse forces forming the envelope 27 is approximately 80. As is clear from the above, the larger the number of pulses constituting the envelope 27, the more the envelope 27 approximates the shape of the characteristic line 25 or 26. Resolution is improved. If the number of pulses σ is small, the envelope curve 2
Since the probability that the area near the maximum value of 7 becomes flat increases, the particle size resolution decreases.

Since the particle detection device shown in FIG. 1 detects particles as described above, the shape of the intensity distribution characteristic line 25 or 26 shown in FIG.
) does not affect the particle size resolution, and in the particle detection device shown in FIG. 1, as is clear from FIG. Q) The uniform intensity distribution area is shown in Figure 10 O)
Compared to the case where the beam light is 6σ], it is stretched and enlarged in the scanning direction. Therefore, even if the tζ beam light 6 is narrowed down to narrow the uniform intensity distribution area of the beam light in order to reduce the detectable particle size, the particles will not be detected. The radial resolution does not decrease, and in the case of a particle detector configured as shown in Q), the deviation width t of the light beam 6 can be set with σ], which can be set independently of the intensity of the beam light. In the case of a particle detection device in which the liquid dual force flow path is set to cut out the irradiation area 24 in FIG. There is no need to narrow the road. That is, the particle detection device shown in FIG. 1 is a particle detection device that can conduct a 1C test within a certain period of time and reduce the detectable particle size without causing a decrease in the volume of the measurement fluid 2 or a decrease in particle size resolution.

FIG. 5 is a configuration diagram of a second embodiment of the present invention (I7), which differs from FIG. 1 in that the arrangement order of the focusing lens 7 and the beam polarizing section 18 is reversed. .

Although it is clear that even if the lens 7 and the polarizing section 18 are arranged in a zigzag arrangement like this, fine particles can be detected in the same manner as in the case of FIG. 1. However, especially in the case of FIG. - Since the lens 71c is disposed near the cell 1, a lens 71c with a short focal length can be used, and the numerical aperture of the lens 7 can be increased, so the beam light 6
As a result, the particle detection device ζ has the advantage of being able to reduce the detectable particle size.

FIG. 6 is a block diagram of a third embodiment of the present invention, which differs from FIG. 1 in that a light receiving mechanism 8 is arranged to receive the forward scattered light of the beam light 6 in the flow cell IIζ. be.

It is clear that fine particles can be detected in the same way as the device 1 in FIG. σ〕
Since the intensity is stronger than the side scattered light as in each embodiment, there is an advantage that fine particles can be easily detected.

FIG. 7 is an explanatory diagram of the configuration of the beam light deflection section 28 which replaces the beam light polarization section 18I shown in FIG. 2F.
29a is an ultrasonic transducer driven by the driving power source 30+; 29b is a photoacoustic medium having as part of its function the function of propagating the ultrasonic waves emitted from the transducer 29a; It also has the function of deflecting the traveling direction of the light beam σ] according to the state of the ultrasonic wave propagating through the medium. 29G is a sound absorbing material that absorbs the ultrasonic waves propagating through the medium 29b. 29 is the above-mentioned vibrator 29
The beam light deflection unit 28 is composed of a deflection element 29 and a power source 30. Also in the beam light deflection unit 28, as shown in the figure, the incident laser beam 4 can be turned into a beam light 6 that vibrates at high speed within an angle of 2θ by the drive power source 30+, so that such a deflection is performed. Part 28
can be used in place of the beam light deflection section 18 in each implementation side of the above-mentioned particle detection device.

Above σ) In each embodiment, the through hole t of the opening member 11
Although ta is made circular, this through hole may be formed with a slit or other shape 1ζ.
The optical axis of each of the above-mentioned embodiments F is relative to the optical axis of the beam light 6.
It is also possible to cross C so that they intersect at a different angle from the angle of intersection at C. In addition, in the present invention 1ζ, the light beam 6 projected onto the particulate-containing measuring liquid 2I is not limited to a beam light having a circular cross section, but may be a cross-sectional shape of a cell 70 or a triaxial A1A! eBIB! l CI C
The spatial direction of z is also not limited to the embodiments described above. Furthermore, in the above-described embodiment, the particle detection was performed on the liquid 1ζ, and the light receiving mechanism 8 was designed to receive the directly scattered light of the projected beam light 6, but in the present invention, the measurement liquid is gaseous. Also, the light receiving mechanism 8
It is also possible to configure a chip ζ so as to receive fluorescence scattering. The detection device according to the present invention is also capable of measuring the flow velocity of the particulate-containing measurement fluid by counting the number of pulses in the electrical signal lOa shown in FIG.

〔Effect of the invention〕

As described above, the present invention includes a beam light irradiation mechanism that irradiates a particulate-containing measurement fluid with a beam light, and a signal that receives scattered light emitted from particulates by the irradiation of the beam light and responds to the scattered light. It consists of a light receiving mechanism that outputs
A particle detection device that detects particles based on the output signal of the light receiving mechanism ■ A beam light irradiation mechanism IC equipped with a beam light deflection section that repeatedly scans the measurement fluid in a straight line with the beam light By virtue of this general configuration, the uniform intensity distribution region of the beam light in the measuring fluid portion irradiated by the beam light is substantially expanded, In addition, the shape of the intensity distribution of the beam light is designed so that it does not affect the particle size resolution of the particle detection device, so there is no reduction in the volume of the particle-containing measurement fluid that can be inspected within a certain period of time, and there is no reduction in particle size resolution. This has the effect of providing a particle detection device that can reduce the detectable particle size.

There is.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the first embodiment of the present invention, Fig. 2 is a block diagram of the main parts in Fig. 1, and Fig. 3 is an explanation of the operation of the particle detection device shown in Figs. 1 and 2. In the figures, FIG. 8 is a plan view, and FIG. 0 is a side view. FIG. 4 is an explanatory diagram corresponding to FIG. 3, and FIGS. 5 and 6 are the same. FIG.
FIG. 10 is an enlarged perspective view of the main part in the figure, and FIG. 10 is a diagram for explaining detection errors, and FIG. 10 (3) is a beam light arrangement diagram. 0 is a beam light σ) intensity distribution diagram. 2...Measurement liquid, 3.19...Beam light irradiation mechanism, 6.16...Beam light % 8.Light receiving mechanism, 17... Fine particles, 18.28・
-...Beam light deflection section. Figure 1

Claims (1)

[Claims] It consists of a beam light irradiation mechanism that irradiates a measurement fluid containing fine particles with a beam light, and a light receiving mechanism that receives scattered light emitted from the fine particles by the irradiation of the beam light and outputs a signal corresponding to the scattered light. , in the particle detection device that detects the particles based on the output signal of the light receiving mechanism, the beam light irradiation mechanism is provided with a beam light deflection unit that repeatedly scans the measurement fluid in a straight line with the beam light. A particle detection device featuring: