JPH04369464A - Light scattering type particle detector - Google Patents

Abstract

PURPOSE:To enhance detection sensitivity by effectively condensing scattering light in the title detector. CONSTITUTION:A concave mirror 19 reflecting the scattering light advancing in the direction opposite to a scattering light detector in the direction of the scattering light detector 15 is provided to the side surface of the flow cell 12 opposed to the scattering light detector 15. In addition to said mirror 19, a convex lens 16 capable of allowing scattering light to straightly advance at the side surface position of the flow cell 12 without refracting the same is arranged to the side surface of the flow cell on the side of the scattering light detector. By this constitution, a fine particle can be detected with still more enhanced detection sensitivity.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light scattering particle detection device, and is particularly suitable for use in a device for detecting fine particles in a flow cell channel.

0002

2. Description of the Related Art A light scattering particle detection device 1 has a flow path 2A provided approximately in the center of a flow cell 2, as shown in FIG.
A sample fluid flowing through the sample fluid is irradiated with light source light LA1 through a condenser lens 3, and when the sample fluid contains fine particles, scattered light obtained from the fine particles is detected by a scattered light detector 5 through a condenser lens 4. The passage of fine particles is detected using the detection signal S1.

0003

[Problems to be Solved by the Invention] However, in this type of conventional light scattering type particle detection device 1, the scattered light generated in the flow path 2A is caused by using a material such as quartz or sapphire as a raw material, as shown in FIG. Based on the difference in refractive index between the cell 2 and air, when the light passes through the thickness of the cell 2 and exits into the air, it is refracted so as to spread outward at the cell outer wall position, and therefore passes through the condenser lens 4. The structure is such that the amount of scattered light produced is reduced.

Therefore, compared to a light scattering particle detector that does not use a flow cell, such as a light scattering particle detector that detects particles in the air, the detection sensitivity of this type of flow cell particle detector is lower. There is a problem where it becomes extremely low.

[0005] Conventionally, methods for solving this problem include, firstly, configuring the light source with a high-output one such as a high-output argon ion laser or a high-output semiconductor laser, and secondly, forming the light source light LA1. When measuring, the laser beam can be narrowed to a small size to measure only a part of the sample fluid, and thirdly, the acceptance angle can be increased by using a short focal length lens as the condenser lens 4 and placing it as close to the flow cell as possible. However, methods have been proposed to increase the light gathering ability as a result.

However, in practice, there is a problem in that when a high-output argon ion laser or a high-output semiconductor laser is used, a large-sized power supply device with an output of several watts is required. Another disadvantage is that if the laser beam is narrowed down, the reliability of the measurement data will decrease. Furthermore, when a condensing lens with a short focal length is used, the lens becomes thick and aberrations occur, resulting in the problem that the condensing ability is still insufficient.

The present invention has been made in consideration of the above points, and aims to propose a light scattering particle detection device that can further improve the light gathering ability of a conventional light scattering particle detection device using a flow cell. It is something.

[0008]

[Means for Solving the Problem] In order to solve the problem, in the first invention, a flow path 12 in a flow cell 12 is provided.
For the fine particles 20 contained in the sample fluid passing through A,
In a light scattering particle detection device that obtains measurement data by converting scattered light obtained by irradiating light source light LA2 into a detection signal S2 in a scattered light detector 15, the scattered light that is scattered in the opposite direction to the scattered light detector 15 is used. Scattered light detector 15
A concave mirror 19 reflects the light in the direction of the scattered light detector 15, and the scattered light reflected by the concave mirror 19 in the direction of the scattered light detector 15 and the scattered light scattered in the direction of the direct scattered light detector 15 are focused on the scattered light detector 1.
5 is provided.

Further, in the second invention, a convex lens 2 having substantially the same refractive index as the flow cell 12 is provided on the side surface 12B of the flow cell on the side of the scattered light detector 15 facing the concave mirror 19.
1 should be provided.

0010

[Operation] In the first invention, by installing the concave mirror 19 on the side surface 12C of the flow cell facing the scattered light detector 15, the scattered light scattered in the opposite direction to the scattered light detector 15 is directed toward the scattered light detector 15. As a result, the amount of scattered light that can be detected by the scattered light detector 15 can be further increased compared to the case where the concave mirror 19 is not installed.

Further, in the second invention, by installing a convex lens 21 having almost the same refractive index as the flow cell on the side surface 12B of the flow cell on the side of the scattered light detector 15,
Scattered light directly scattered in the direction of the scattered light detector 15 and scattered light reflected in the direction of the scattered light detector 15 by the concave mirror,
The light can be incident on the condenser lens 14 without being refracted or diffused at the side surface 12B of the flow cell on the side of the scattered light detector 15, and as a result, the amount of scattered light that can be detected by the scattered light detector 15 can be further increased.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

(1) First Embodiment In FIGS. 1 and 2, the flow cell 12 of the light scattering particle detection device 11 has a substantially square cross-sectional shape, and a flow path 12A is formed at the center of the flow cell 12. The sample fluid flowing in the sample fluid 12A is irradiated with light source light LA2 focused by the condenser lens 13, and when there are particles in the sample fluid, the scattered light is scattered around.

Scattered light emitted from one side surface 12B of the flow cell 12 is focused by a condenser lens 14, enters a scattered light detector 15, and is converted into a detection signal S2, thereby obtaining measurement data. It is done like this.

In addition to this configuration, a convex lens 16 having almost the same refractive index as the flow cell 12 is provided on the side surface 12C opposite to the side surface 12B of the flow cell 12, and an adhesive having the same refractive index as the flow cell 12 is provided. 17. A reflective layer 18 is attached to the outer surface of the convex lens 16 by, for example, vapor deposition, thereby forming a concave mirror 19.

The relationship between the width of the channel 12A of the flow cell 12 and the concave mirror 19 is such that the sample fluid passes through approximately the center of the channel 12A and the focal point of the concave mirror 19 is at the position of the sample fluid. Selected. In order to substantially satisfy this condition, the width of the flow path 12A is selected to be a small value, and the radius of curvature of the concave mirror 19 is selected to be as large as possible,
When the width of the flow path 12A is "1", the radius of curvature of the concave mirror 19 is selected to be approximately "8" or more. As a preferable selection example, the width of the channel 12A of the flow cell 12 is selected to be about 0.5 [mm] in consideration of cleaning when the channel 12A becomes contaminated, and the radius of curvature of the concave mirror 19 is selected to be about 0.5 [mm]. 4 to 5 [
mm].

In the configurations shown in FIGS. 1 and 2, the light source light LA
Among the scattered light scattered by irradiating the sample fluid in the flow channel 12A, the scattered light scattered in the direction of the scattered light detector 15 is refracted at the side surface 12B position of the flow cell 12 and spread to the surroundings. The light is emitted in the direction of the condenser lens 14 while being bent. In this way, among the scattered light emitted from the side surface 12B, the scattered light that passes through the condenser lens 14 enters the scattered light detector 15 through the condenser lens 14.

On the other hand, among the scattered light scattered by the sample fluid, the side surface 12 opposite to the scattered light detector 15
The scattered light scattered toward C is reflected by the concave mirror 19 and returned to the channel 12A, and further passes through the channel 12A position and is directly scattered by the sample fluid in the direction of the scattered light detector 15. Together with the scattered light that travels towards the side surface 12B and is thus scattered directly in the direction of the scattered light detector 15, it is refracted at the side surface 12B and is refracted by the condenser lens 14.
The light is focused on the scattered light detector 15 by the following.

Here, the refractive index of the convex lens 16 and adhesive 17 is selected to be approximately the same value as the refractive index of the flow cell, and the focal point of the concave mirror 19 is selected to be at the position of the flow path 12A. The scattered light reflected by the concave mirror 19 is focused so as to return to the flow path 12A as it is.

According to the configurations shown in FIGS. 1 and 2, the concave mirror 19 is provided on the side surface of the flow cell 12 on the side opposite to the scattered light detector 15 with the flow path 12A in between. , the scattered light scattered in the direction of the concave mirror 19 can be reflected in the direction of the flow path 12A, and the reflected scattered light can be used as detection light for the scattered light detector 15. In this way, the detection sensitivity of scattered light in the light scattering type particle detection device 11 can be further increased according to the amount of scattered light reflected by the concave mirror 19.

(2) Second Embodiment FIG. 3 shows parts corresponding to those in FIGS. 1 and 2 denoted by the same reference numerals.
4 shows a second embodiment, in which a convex lens 21 is placed between the side surface 12B of the flow cell 12 and the condenser lens 14.
It has the same configuration as FIGS. 1 and 2 except that it is provided with.

The convex lens 21 has almost the same refractive index as the flow cell 12, and the convex lens 21 has a refractive index similar to that of the flow cell 12.
Side surface 1 is bonded by adhesive 22 having approximately the same refractive index as
It is fixed on 2B.

In the configurations of FIGS. 3 and 4, the light source light LA
2 irradiates the sample fluid in the channel 12A, among the scattered light, the scattered light in the direction of the scattered light detector 15 and the scattered light reflected by the concave mirror 19, passing through the channel 12A position and directed toward the side surface 12B. The scattered light traveling along the flow cell 12 passes straight through the convex lens 21 and the adhesive 22 having substantially the same refractive index as the flow cell 12 at the position of the side surface 12B without being refracted, and enters the condenser lens 14.

Thus, according to the configurations of FIGS. 3 and 4, compared to the configurations of FIGS. 1 and 2, the side surface 1 of the flow cell 12
The optical density of the scattered light incident on the condensing lens 14 that is not refracted when passing through the scattered light detector 15 can be increased, and therefore the detection sensitivity of the detection signal S2 obtained from the scattered light detector 15 can be further increased.

(3) Other Embodiments In the embodiments of FIGS. 1 and 2 and the embodiments of FIGS. 3 and 4 described above, a convex lens 16 having approximately the same refractive index as the flow cell is provided between the flow cell 12 and the concave mirror 19. has been described, but instead of this, a convex lens 16 is provided.
Even if the concave mirror 19 is attached to the side surface 12C of the flow cell 12 in close contact with the side surface 12C of the flow cell 12, the same effect as described above can be obtained.

Furthermore, in the embodiments shown in FIGS. 1 and 2, as well as FIGS. 3 and 4, the cross-sectional shape of the flow cell 12 is square, but the present invention is not limited to this, and other cross-sectional shapes, such as a circular cross-section, can be used. It can also be applied to things.

Furthermore, in the embodiments shown in FIGS. 3 and 4 described above, the cross-sectional shape of the side surface of the flow cell 12 is square, so that the convex lens 21 provided at the side surface 12B of the flow cell 12 is a plano-convex lens. However, the present invention is not limited to this, and a convex lens having a shape that matches the side surface shape of the flow cell can be applied.

Further, in the embodiments shown in FIGS. 3 and 4 described above, the flow cell 12 and the convex lens 21 are fixed using the adhesive 22 having approximately the same refractive index as the flow cell, but the present invention is not limited to this. First, in addition to fastening with a fixing means such as a screw, the gap between the flow cell 12 and the convex lens 21 may be filled with a filler having approximately the same refractive index as the flow cell 12.

[0029]

As described above, according to the present invention, the side surface of the flow cell opposite to the scattered light detector is used as a means for condensing scattered light obtained from fine particles in the flow cell channel onto the scattered light detector. By installing a concave mirror in the
The amount of scattered light incident on the dispersion scattered light detector can be increased, and as a result, a particle detection device with even higher detection sensitivity can be realized.

Furthermore, according to the present invention, in addition to this, a convex lens having approximately the same refractive index as the flow cell is provided at the emission position of the scattered light from the flow cell to the scattered light detector. It is possible to prevent the scattered light emitted in the direction from being diffused by refraction, and it is possible to realize a particle detection device with even higher detection sensitivity.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the overall configuration of a first embodiment of a light scattering particle detection device according to the present invention.

FIG. 2 is a partially enlarged view showing the configuration near the flow cell in FIG. 1;

FIG. 3 is a sectional view showing the overall configuration of a second embodiment of the light scattering particle detection device according to the present invention.

FIG. 4 is a partially enlarged view showing the configuration near the flow cell in FIG. 3;

FIG. 5 is a sectional view showing the overall configuration of a conventional light scattering particle detection device.

FIG. 6 is a partially enlarged view showing the configuration near the flow cell in FIG. 5;

[Explanation of symbols]

2, 12...flow cell, 2A, 12A...channel, 3,
4, 13, 14... Condensing lens, 5, 15... Scattered light detector, 6, 20... Fine particles, 16... Convex lens, 17...
...Adhesive, 18...Reflection layer, 19...Concave mirror, LA1,
LA2...Light source light, S1, S2...Detection signal.

Claims (2)

[Claims] [Claim 1] Scattered light obtained by irradiating light from a light source to microparticles contained in a sample fluid passing through a flow path in a flow cell is converted into a detection signal in a scattered light detector to obtain measurement data. A light scattering particle detection device to be obtained includes a concave mirror that reflects the scattered light scattered in the opposite direction to the scattered light detector toward the scattered light detector, and a concave mirror that reflects the scattered light that is reflected toward the scattered light detector by the concave mirror and the scattered light that is directly scattered. A light scattering particle detection device comprising a condenser lens that focuses scattered light in the direction of a photodetector and guides it to the scattered light detector. 2. A convex lens having substantially the same refractive index as that of the flow cell is provided on a side surface of the flow cell on the scattered light detector side facing the concave mirror.
The light-scattering particle detection device described in 2.