JPH09178645A - Light-scattering type particle counter - Google Patents
Light-scattering type particle counterInfo
- Publication number
- JPH09178645A JPH09178645A JP7338435A JP33843595A JPH09178645A JP H09178645 A JPH09178645 A JP H09178645A JP 7338435 A JP7338435 A JP 7338435A JP 33843595 A JP33843595 A JP 33843595A JP H09178645 A JPH09178645 A JP H09178645A
- Authority
- JP
- Japan
- Prior art keywords
- light
- laser diode
- laser
- type particle
- scattering type
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000002245 particle Substances 0.000 title claims abstract description 38
- 238000000149 argon plasma sintering Methods 0.000 title claims abstract description 24
- 238000005259 measurement Methods 0.000 claims description 7
- 230000001678 irradiating effect Effects 0.000 claims 1
- 230000003287 optical effect Effects 0.000 abstract description 3
- 230000007704 transition Effects 0.000 abstract description 2
- 239000012530 fluid Substances 0.000 description 11
- 230000010355 oscillation Effects 0.000 description 11
- 238000010586 diagram Methods 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 238000012545 processing Methods 0.000 description 4
- 238000012360 testing method Methods 0.000 description 3
- 235000008694 Humulus lupulus Nutrition 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 230000002265 prevention Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/062—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes
- H01S5/06209—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in single-section lasers
- H01S5/06213—Amplitude modulation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/062—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes
- H01S5/06209—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in single-section lasers
- H01S5/0622—Controlling the frequency of the radiation
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、レーザダイオード
を光源とする光散乱式粒子計数装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light scattering type particle counting device using a laser diode as a light source.
【０００２】[0002]
【従来の技術】光散乱式粒子計数装置の光源として、小
型・軽量で安価なレーザダイオードが広く使用されてい
る。しかし、レーザダイオードでは、発振波長が他の波
長へ瞬間的にホップするモードホップ現象が起きると、
発振波長が離散的に変動するので発振光強度が変動し、
モードホップノイズが発生する。モードホップノイズが
発生すると測定領域に粒子が存在しないにも拘らず粒子
が存在するものとして計数する、いわゆる偽計数という
現象が生じる。2. Description of the Related Art A small, lightweight and inexpensive laser diode is widely used as a light source of a light scattering type particle counting device. However, in laser diodes, when a mode-hop phenomenon occurs in which the oscillation wavelength momentarily hops to another wavelength,
Since the oscillation wavelength fluctuates discretely, the oscillation light intensity fluctuates,
Mode hop noise occurs. When mode hop noise occurs, there occurs a phenomenon of so-called false counting, in which particles are counted as being present even though no particles are present in the measurement area.
【０００３】モードホップ現象の発生原因としては、レ
ーザダイオードを縦モード（発振波長）がシングルモー
ドであるように動作させたとき、次の三つ（（１）〜
（３））が考えられる。（１）としては、レーザダイオ
ード自身が受ける温度変動や駆動電流の変動によって発
振波長が変動することによる。（２）としては、レーザ
ダイオードから出射したレーザ光の一部が何らかの理由
で再びレーザダイオードに戻る、いわゆる戻り光によ
る。（３）としては、発振効率の量子力学的な揺らぎが
あったりすると発振波長が変動することによる。The cause of the mode hopping phenomenon is as follows when the laser diode is operated so that the longitudinal mode (oscillation wavelength) is a single mode.
(3)) is considered. The reason (1) is that the oscillation wavelength varies due to the temperature variation and the driving current variation of the laser diode itself. As (2), a part of the laser light emitted from the laser diode returns to the laser diode again for some reason, that is, so-called return light. (3) The reason is that the oscillation wavelength fluctuates when there is a quantum mechanical fluctuation of the oscillation efficiency.
【０００４】そこで、モードホップノイズによる偽計数
を抑制するために、レーザダイオードの駆動電流を一定
にし、レーザダイオードを一定温度に保ち、更に戻り光
を防止するという対策を施した光散乱式粒子計数装置が
提案されている。Therefore, in order to suppress the false counting due to the mode hop noise, the light scattering type particle counting in which the driving current of the laser diode is made constant, the laser diode is kept at a constant temperature, and the returning light is further prevented is taken. A device has been proposed.
【０００５】従来の光散乱式粒子計数装置は、図３に示
すように、レーザ光Ｌを出射する光源部１と、レーザ光
Ｌを被検流体Ｍに集光させる照射レンズ系２と、被検流
体Ｍを通過させる流路を形成したフローセル３と、被検
流体Ｍ中の粒子が発生する散乱光Ｓを集光する受光レン
ズ系４と、集光した散乱光Ｓを光電変換する光電変換素
子５と、光電変換素子５の出力信号を受けて粒子を計数
する演算処理部６から構成されている。As shown in FIG. 3, the conventional light-scattering type particle counting device includes a light source section 1 for emitting a laser beam L, an irradiation lens system 2 for converging the laser beam L on a fluid M to be tested, and an object to be measured. A flow cell 3 having a flow path for passing the test fluid M, a light receiving lens system 4 for collecting scattered light S generated by particles in the test fluid M, and photoelectric conversion for photoelectrically converting the collected scattered light S. The element 5 and the arithmetic processing unit 6 that receives the output signal of the photoelectric conversion element 5 and counts particles.
【０００６】光源部１は、レーザダイオード７と、レー
ザダイオード７に定電流駆動方式（レーザダイオード７
に常時一定の駆動電流を流す方式）により直流駆動電流
を供給してシングルモード（単一の波長で発振する状
態）で発光させるレーザ駆動回路８と、レーザダイオー
ド７を一定温度に制御する温度制御部９とからなる。更
に、温度制御部９は、レーザダイオード７を加熱冷却す
る加熱・冷却部９ａと、レーザダイオード７自身の温度
を検出する温度センサ９ｂと、温度センサ９ｂの検出信
号を受けレーザダイオード７の温度が所望の温度になる
ように加熱・冷却部９ａに電力を供給する温度制御回路
９ｃから構成されている。The light source section 1 includes a laser diode 7 and a constant current driving method for the laser diode 7 (laser diode 7
A laser drive circuit 8 for supplying a DC drive current to emit light in a single mode (a state of oscillating at a single wavelength) and a temperature control for controlling a laser diode 7 at a constant temperature. And part 9. Furthermore, the temperature control unit 9 receives a detection signal from the heating / cooling unit 9a that heats and cools the laser diode 7, a temperature sensor 9b that detects the temperature of the laser diode 7 itself, and the temperature of the laser diode 7 when the temperature sensor 9b receives a detection signal. The temperature control circuit 9c is configured to supply electric power to the heating / cooling unit 9a so that the temperature reaches a desired temperature.
【０００７】照射レンズ系２は、レーザ光Ｌがレンズ平
面へ垂直入射すると、一部が反射して戻り光となるの
で、垂直入射しないように構成されている。演算処理部
６は、光電変換素子５の出力信号を増幅する増幅器６ａ
と、増幅器６ａの出力信号に基づいて粒径弁別する波高
分析器６ｂと、波高分析器６ｂの出力信号を計数する計
数器６ｃから構成されている。The irradiation lens system 2 is constructed so that, when the laser light L is vertically incident on the lens plane, a part of the laser light L is reflected and becomes return light. The arithmetic processing unit 6 includes an amplifier 6a that amplifies the output signal of the photoelectric conversion element 5.
And a wave height analyzer 6b for discriminating the particle size based on the output signal of the amplifier 6a, and a counter 6c for counting the output signal of the wave height analyzer 6b.
【０００８】[0008]
【発明が解決しようとする課題】従来の技術において
は、図３に示すように、温度制御部９を備えたり、照射
レンズ系２に対して戻り光を防止するための工夫を施し
ているので、装置が複雑化するという欠点がある。しか
も、モードホップ現象を引き起こす本質的な発生原因
（前述の発生原因（３））に対する対策が採られていな
いので、モードホップノイズの抑制は十分ではないとい
う問題点も有していた。また、モードホップノイズの発
生を抑える他の方法として、縦モードをロックして動作
する分布帰還型レーザ（distributed feedback laser）
を光源として使用することも考えられるが、これは非常
に高価でありまた取り扱いも難しいという問題点も有し
ていた。In the prior art, as shown in FIG. 3, a temperature control unit 9 is provided and the irradiation lens system 2 is devised to prevent returning light. However, there is a drawback that the device becomes complicated. Moreover, since no countermeasure is taken against the essential cause of the mode-hop phenomenon (the above-mentioned cause (3)), there is a problem that the mode-hop noise is not sufficiently suppressed. Another method of suppressing the generation of mode hop noise is a distributed feedback laser that operates by locking the longitudinal mode.
It can be considered to use as a light source, but it has a problem that it is very expensive and difficult to handle.
【０００９】本発明は、従来の技術が有するこのような
問題点に鑑みてなされたものであり、その目的とすると
ころは、レーザダイオードのモードホップノイズを抑制
することにより偽計数の発生を効果的に低減する光散乱
式粒子計数装置を提供しようとするものである。The present invention has been made in view of the above problems of the prior art, and its object is to suppress the generation of false counts by suppressing the mode hop noise of the laser diode. The present invention aims to provide a light-scattering type particle counting device that can be effectively reduced.
【００１０】[0010]
【課題を解決するための手段】上記課題を解決すべく本
発明は、レーザダイオードから出射するレーザ光を測定
領域に照射し、この測定領域に存在する粒子が発生する
散乱光に基づいて粒子を計数する光散乱式粒子計数装置
において、前記レーザダイオードを直流電流に高周波成
分を重畳した駆動電流を出力するレーザ駆動回路により
駆動し、前記レーザダイオードの縦モードをマルチモー
ドにするものである。In order to solve the above-mentioned problems, the present invention irradiates a laser beam emitted from a laser diode onto a measurement region and causes the particles existing in the measurement region to generate particles based on scattered light generated by the particles. In a light-scattering particle counting device for counting, the laser diode is driven by a laser drive circuit that outputs a drive current in which a high frequency component is superimposed on a direct current, and the longitudinal mode of the laser diode is set to a multimode.
【００１１】[0011]
【発明の実施の形態】以下に本発明の実施の形態を添付
図面に基づいて説明する。ここで、図１は本発明に係る
光散乱式粒子計数装置の構成図、図２は同じく偽計数の
程度を示す特性図である。なお、図１において図３と同
一符号を付して示す構成要素は図３の構成要素と同一な
のでその説明を省略する。Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a configuration diagram of a light scattering type particle counting device according to the present invention, and FIG. 2 is a characteristic diagram similarly showing the degree of false counting. Note that, in FIG. 1, the constituent elements denoted by the same reference numerals as those in FIG. 3 are the same as the constituent elements in FIG.
【００１２】本発明に係る光散乱式粒子計数装置は、図
１に示すように、レーザ光Ｌを出射する光源部１０と、
レーザ光Ｌを被検流体Ｍに集光させる照射レンズ系１１
と、被検流体Ｍを通過させる流路を形成したフローセル
３と、被検流体Ｍ中の粒子が発生する散乱光Ｓを集光す
る受光レンズ系４と、集光した散乱光Ｓを光電変換する
光電変換素子５と、光電変換素子５の出力信号を受けて
粒子を計数する演算処理部６から構成されている。な
お、照射レンズ系１１には、従来技術の照射レンズ系２
と異なり、戻り光防止策を施していない。The light-scattering particle counting device according to the present invention, as shown in FIG. 1, includes a light source section 10 for emitting a laser beam L,
Irradiation lens system 11 for focusing the laser light L on the fluid M to be measured
A flow cell 3 having a flow path for passing the fluid M to be tested, a light receiving lens system 4 for collecting scattered light S generated by particles in the fluid M to be tested, and photoelectrically converting the collected scattered light S. The photoelectric conversion element 5 and the arithmetic processing unit 6 that receives the output signal of the photoelectric conversion element 5 and counts particles. The irradiation lens system 11 includes the irradiation lens system 2 of the conventional technology.
Unlike, it does not have a back light prevention measure.
【００１３】光源部１０は、レーザダイオード７と、レ
ーザダイオード７に駆動電流を供給するレーザ駆動回路
１２で構成されている。そして、レーザ駆動回路１２
は、直流電流に高周波電流を重畳した駆動電流を出力す
るようにしている。レーザ駆動回路１２においては、定
電流駆動方式を採用しているため、レーザダイオード７
の発振効率等が温度により変動しても、電流値を一定に
維持できる。なお、直流電流の値は、使用するレーザダ
イオード７の種類に応じて適宜選択される。The light source section 10 comprises a laser diode 7 and a laser drive circuit 12 which supplies a drive current to the laser diode 7. Then, the laser drive circuit 12
Outputs a driving current in which a high frequency current is superimposed on a direct current. Since the laser drive circuit 12 adopts the constant current drive system, the laser diode 7
The current value can be kept constant even if the oscillation efficiency and the like fluctuate with temperature. The value of the direct current is appropriately selected according to the type of laser diode 7 used.
【００１４】直流電流に重畳する高周波電流は、レーザ
ダイオード７の縦モードがマルチモード動作をするよう
な条件に設定されている。周波数としては、過渡的に複
数の波長で発振する緩和時間を目安として設定されてお
り、例えば３００〜６００ＭＨzとしている。また、振
幅としては、少なくとも縦モードがホップするようなレ
ベルに設定されている。このレベルの設定は、光スペク
トルアナライザ等を用いて発振光の縦モードをモニタ
し、縦モードがマルチモード動作をするように調整して
行う。なお、高周波電流の波形は、正弦波の他に矩形波
等を使用することもできる。この場合、矩形波のデュー
ティ比を変えることによって効率よくマルチモード動作
をするようにしてよい。The high frequency current superimposed on the direct current is set under the condition that the longitudinal mode of the laser diode 7 operates in a multimode. The frequency is set based on a relaxation time that transiently oscillates at a plurality of wavelengths, and is set to, for example, 300 to 600 MHz. Further, the amplitude is set to such a level that at least the longitudinal mode hops. This level is set by monitoring the longitudinal mode of the oscillated light using an optical spectrum analyzer or the like and adjusting so that the longitudinal mode performs multimode operation. As the waveform of the high frequency current, a rectangular wave or the like can be used instead of the sine wave. In this case, the multimode operation may be efficiently performed by changing the duty ratio of the rectangular wave.
【００１５】以上のように構成した光散乱式粒子計数装
置の作用について説明する。直流電流に高周波電流を重
畳した駆動電流を出力するレーザ駆動回路１２によって
レーザダイオード７を駆動することにより、縦モードが
強制的にマルチモード（複数の縦モードが同時に存在す
ること）になる。従って、縦モードが遷移する際の光出
力の変化量を互いに相殺するので全体としての変化量を
小さくすることが可能になり、実質的にモードホップノ
イズも抑制される。The operation of the light-scattering type particle counting device configured as described above will be described. By driving the laser diode 7 by the laser drive circuit 12 that outputs a drive current in which a high frequency current is superimposed on a direct current, the longitudinal mode is forcibly set to the multimode (a plurality of longitudinal modes exist simultaneously). Therefore, the change amounts of the optical output at the time of the transition of the longitudinal mode cancel each other out, so that it is possible to reduce the change amount as a whole, and the mode hop noise is also substantially suppressed.
【００１６】モードホップノイズの抑制は、レーザダイ
オード７の使用温度範囲内であればどの温度においても
行われるので、図３に示す従来の光散乱式粒子計数装置
に比べ、使用温度範囲が広がる。このようにモードホッ
プノイズの抑制が可能になることによって、モードホッ
プノイズを起因とする偽計数が低減され、測定値の信頼
性の向上や使用可能環境の拡大を図ることができる。ま
た、本発明に係る光散乱式粒子計数装置は、従来の光散
乱式粒子計数装置を構成する温度制御部９や戻り光防止
策を施した照射レンズ系２を必要としないので小型軽量
で低価格となる。Since the mode hop noise is suppressed at any temperature within the operating temperature range of the laser diode 7, the operating temperature range is widened as compared with the conventional light scattering type particle counting device shown in FIG. Since the mode hop noise can be suppressed as described above, the false count due to the mode hop noise can be reduced, and the reliability of the measured value can be improved and the usable environment can be expanded. Further, the light-scattering particle counting device according to the present invention does not require the temperature control unit 9 or the irradiation lens system 2 provided with a return light prevention measure, which constitutes the conventional light-scattering particle counting device, so that it is small, lightweight and low in size. It will be the price.
【００１７】図２に示す特性図は、本発明に係る光散乱
式粒子計数装置の測定結果であり、図４に示す特性図
は、従来の光散乱式粒子計数装置の測定結果である。図
２及び図４において、曲線ｔは光散乱式粒子計数装置が
置かれている恒温槽内部の温度変化を示し、読みは右側
の縦軸（単位：℃）に従う。また、曲線ａ及び曲線ｂは
夫々の光散乱式粒子計数装置に被検流体Ｍとして純水を
流した状態でカウントしたレベルを示し、読みは左側の
対数軸（単位：１０ｍｌ／ｍｉｎ）に従う。なお、横軸
は時間軸（単位：時間）である。The characteristic diagram shown in FIG. 2 is the measurement result of the light scattering type particle counting device according to the present invention, and the characteristic diagram shown in FIG. 4 is the measurement result of the conventional light scattering type particle counting device. In FIG. 2 and FIG. 4, the curve t shows the temperature change inside the thermostatic chamber in which the light scattering type particle counting device is placed, and the reading follows the right vertical axis (unit: ° C.). Curves a and b show the levels counted with pure water as the test fluid M flowing through the respective light scattering type particle counters, and the readings follow the logarithmic axis on the left side (unit: 10 ml / min). The horizontal axis is the time axis (unit: time).
【００１８】図２及び図４の特性図を比較すると、図２
の曲線ａは被検流体Ｍとしての純水に対応しており、通
常数１０ｍｌ／ｍｉｎ程度のレベルを示すのみで、図４
の曲線ｂの最大値約１万カウントと比べて偽計数がほと
んど生じていない。Comparing the characteristic diagrams of FIGS. 2 and 4, FIG.
The curve a in FIG. 4 corresponds to pure water as the fluid M to be tested, and usually shows only a level of several tens of ml / min.
Compared with the maximum value of the curve b of about 10,000 counts, almost no false count occurs.
【００１９】また、図１において、被検流体Ｍがフロー
セル３を通過するようにし、フローセル３内を通過する
被検流体Ｍにレーザ光Ｌを照射するようにしているが、
フローセル３を使用しない構成でもよい。Further, in FIG. 1, the fluid M to be measured is allowed to pass through the flow cell 3 and the fluid M to be tested passing through the inside of the flow cell 3 is irradiated with the laser light L.
The flow cell 3 may not be used.
【００２０】なお、レーザダイオード７の発振光の安定
化に定電流駆動方式を採用しているが、光出力制御方式
を採用することもできる。光出力制御方式とは、レーザ
ダイオード７の発振光をフォトダイオード等により検出
して、フィードバック制御により発振光が一定になるよ
うに駆動電流を制御する方式である。Although the constant current driving method is used to stabilize the oscillation light of the laser diode 7, a light output control method can also be used. The light output control method is a method in which the oscillation light of the laser diode 7 is detected by a photodiode or the like and the drive current is controlled by feedback control so that the oscillation light becomes constant.
【００２１】[0021]
【発明の効果】以上説明したように本発明によれば、レ
ーザダイオードを直流電流に高周波成分を重畳した駆動
電流により駆動し、レーザダイオードの縦モードをマル
チモード動作させるので、比較的簡易な構成であるにも
拘らず、広い温度範囲にわたってモードホップノイズを
抑制することが可能となり、偽計数を効果的に低減する
ことができる。As described above, according to the present invention, the laser diode is driven by the drive current in which the high frequency component is superimposed on the direct current, and the longitudinal mode of the laser diode is operated in the multi-mode. Therefore, the structure is relatively simple. However, the mode hop noise can be suppressed over a wide temperature range, and the false count can be effectively reduced.
【図１】本発明に係る光散乱式粒子計数装置の構成図FIG. 1 is a configuration diagram of a light scattering type particle counting device according to the present invention.
【図２】本発明に係る光散乱式粒子計数装置における偽
計数の程度を示す特性図FIG. 2 is a characteristic diagram showing the degree of false counting in the light scattering type particle counting device according to the present invention.
【図３】従来の光散乱式粒子計数装置の構成図FIG. 3 is a block diagram of a conventional light scattering type particle counting device.
【図４】従来の光散乱式粒子計数装置における偽計数の
程度を示す特性図FIG. 4 is a characteristic diagram showing the degree of false counting in a conventional light scattering type particle counting device.
３…フローセル、４…受光レンズ系、５…光電変換素
子、６…演算処理部、７…レーザダイオード、１０…光
源部、１１…照射レンズ系、１２…レーザ駆動回路、Ｌ
…レーザ光、Ｍ…被検流体、Ｓ…散乱光。3 ... Flow cell, 4 ... Light receiving lens system, 5 ... Photoelectric conversion element, 6 ... Arithmetic processing section, 7 ... Laser diode, 10 ... Light source section, 11 ... Irradiation lens system, 12 ... Laser drive circuit, L
... laser light, M ... fluid to be tested, S ... scattered light.
Claims (1)
を測定領域に照射し、この測定領域に存在する粒子が発
生する散乱光に基づいて粒子を計数する光散乱式粒子計
数装置において、前記レーザダイオードを直流電流に高
周波成分を重畳した駆動電流を出力するレーザ駆動回路
により駆動し、前記レーザダイオードの縦モードをマル
チモードにすることを特徴とする光散乱式粒子計数装
置。1. A light-scattering particle counter for irradiating a laser beam emitted from a laser diode onto a measurement region and counting the particles based on scattered light generated by particles existing in the measurement region. A light-scattering particle counting device, characterized in that the laser diode is driven by a laser drive circuit that outputs a drive current in which a high-frequency component is superimposed on a direct current, and the longitudinal mode of the laser diode is set to a multimode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7338435A JPH09178645A (en) | 1995-12-26 | 1995-12-26 | Light-scattering type particle counter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7338435A JPH09178645A (en) | 1995-12-26 | 1995-12-26 | Light-scattering type particle counter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09178645A true JPH09178645A (en) | 1997-07-11 |
Family
ID=18318132
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7338435A Pending JPH09178645A (en) | 1995-12-26 | 1995-12-26 | Light-scattering type particle counter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09178645A (en) |
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| KR100807433B1 (en) * | 2002-10-30 | 2008-02-25 | 니혼 덴산 산쿄 가부시키가이샤 | Particle counter |
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-
1995
- 1995-12-26 JP JP7338435A patent/JPH09178645A/en active Pending
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| KR100807433B1 (en) * | 2002-10-30 | 2008-02-25 | 니혼 덴산 산쿄 가부시키가이샤 | Particle counter |
| US7002682B2 (en) | 2004-02-13 | 2006-02-21 | Hach Ultra Analytics, Inc. | Method and apparatus for operating a laser in an extinction-type optical particle detector |
| US7755760B2 (en) | 2004-12-21 | 2010-07-13 | Rion Co., Ltd. | Particle counter for measuring floating particles which can effectively reduce false counts |
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| JP2012108161A (en) * | 2012-03-09 | 2012-06-07 | Sysmex Corp | Sample analyzer and sample analysis method |
| WO2015012004A1 (en) * | 2013-07-23 | 2015-01-29 | ソニー株式会社 | Particle analysis device and particle analysis method |
| US10031063B2 (en) | 2013-07-23 | 2018-07-24 | Sony Corporation | Particle analysis apparatus and method for optically detecting particles |
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| JP2018513971A (en) * | 2015-04-02 | 2018-05-31 | パーティクル・メージャーリング・システムズ・インコーポレーテッド | Laser noise detection and mitigation in particle counters |
| CN107305177A (en) * | 2016-04-21 | 2017-10-31 | 易幼文 | A kind of particulate matter visualization device and portable particulate matter detecting system |
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