JP4003809B2 - Method and apparatus for measuring turbidity and fine particles - Google Patents
Method and apparatus for measuring turbidity and fine particles Download PDFInfo
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- 239000010419 fine particle Substances 0.000 title claims description 50
- 238000000034 method Methods 0.000 title claims description 19
- 230000003287 optical effect Effects 0.000 claims description 84
- 239000004065 semiconductor Substances 0.000 claims description 31
- 239000002245 particle Substances 0.000 claims description 26
- 230000000903 blocking effect Effects 0.000 claims description 25
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 25
- 238000006243 chemical reaction Methods 0.000 claims description 6
- 238000005259 measurement Methods 0.000 claims description 2
- 238000000691 measurement method Methods 0.000 claims description 2
- 239000011859 microparticle Substances 0.000 claims 2
- 241000223935 Cryptosporidium Species 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 2
- 241000195493 Cryptophyta Species 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000008213 purified water Substances 0.000 description 1
- 238000000790 scattering method Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
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Description
本発明は濁度および微粒子の測定方法とその装置に関する。 The present invention relates to a method and apparatus for measuring turbidity and fine particles.
１９９６年のクリプトスポリジウム流出事故により、「クリプトスポリジウムによって水道原水が汚染されるおそれのある浄水場ではろ過池出口の濁度を０．１度以下に維持すること」という暫定対策指針が厚生省から発表され、濁度０．１度以下を安定に測定できるオンラインの濁度計が必要となった。そして、これまでに半導体レーザを光源に用い、微粒子が光ビームを通過する際に生じる回折縞をカウントし、カウント数を濁度に変換する特許文献１に記載のレーザ濁度計や、微粒子が光ビームを通過する際に、粒径に応じた波高値で観測される散乱光を粒径区分ごとにカウントし、カウントされた一つ一つの信号を微粒子の大きさに応じた濁度に変換する本発明者らが出願した特許文献２に記載の微粒子カウント式高感度濁度計などが開発されている。また、前記事故以降の上水分野では、微粒子監視が普及し始めている。 A provisional countermeasure guideline announced by the Ministry of Health, Labor and Welfare that the turbidity of raw water in a water treatment plant that may be contaminated by Cryptosporidium is maintained at 0.1 degrees or less at the basin outlet of the filtration basin due to a spill of Cryptosporidium in 1996 Therefore, an on-line turbidimeter that can stably measure turbidity of 0.1 degrees or less is required. The laser turbidimeter described in Patent Document 1 that uses a semiconductor laser as a light source, counts the diffraction fringes generated when the fine particles pass through the light beam, and converts the count number to turbidity. When passing through the light beam, the scattered light observed at the crest value according to the particle size is counted for each particle size category, and each counted signal is converted to turbidity according to the size of the fine particles. The fine particle count type high sensitivity turbidimeter described in Patent Document 2 filed by the present inventors has been developed. In the field of water supply after the accident, particulate monitoring has begun to spread.
微粒子カウンタの測定方式には、光ビームを試料水に照射し、光ビームの観測領域を微粒子が通過したときに生ずる散乱光パルス信号をカウントする散乱光方式と、光ビームの観測領域を微粒子が通過したときに生ずる、透過光量の減光パルス信号をカウントする光遮断方式とがある。光遮断方式の最小検出粒径は１〜２μｍであり、この粒径以上が光遮断方式の測定粒径となる。散乱光方式の最小検出粒径はパルス信号を検出する受光光学系の位置によって異なるが、側方散乱光方式で０．１μｍ以下、前方散乱光方式で０．１〜０．２μｍである。側方散乱方式では、前記クリプトスポリジウムなどの生物ように大きさがある程度揃い、屈折率が水に近い物質に対してほとんど感度を持たない場合があることが知られている。前方散乱光方式の場合は、前記生物のように光ビームの波長と比較して同程度以上に大きくなると、ほとんどが前方に向けて光ビームが散乱されるようになるので、側方散乱光方式と比較すると屈折率に対する影響は非常に小さいが、吸収成分を検出していない分だけ光遮断方式より粒径に対する感度が小さくなり、実際の大きさより小さい利粒子としてカウントされる場合がある。 The measurement method of the fine particle counter includes a scattered light method in which a sample beam is irradiated with a light beam and the scattered light pulse signal generated when the fine particle passes through the observation region of the light beam, and the observation region of the light beam is made up of fine particles. There is a light blocking method that counts a dimming pulse signal of a transmitted light amount that occurs when the light passes. The minimum detectable particle size of the light blocking method is 1 to 2 μm, and the particle size equal to or larger than this particle size is the measured particle size of the light blocking method. The minimum detection particle diameter of the scattered light method varies depending on the position of the light receiving optical system that detects the pulse signal, but is 0.1 μm or less in the side scattered light method and 0.1 to 0.2 μm in the forward scattered light method. It is known that the side-scattering method may have almost no sensitivity to a substance having a uniform size and a refractive index close to water, such as the living organism such as Cryptosporidium. In the case of the forward scattered light method, since the light beam is mostly scattered toward the front when it becomes larger than the wavelength of the light beam as in the case of the living thing, the side scattered light method Compared with, the influence on the refractive index is very small, but the sensitivity to the particle size is smaller than that of the light blocking method by the amount that the absorption component is not detected, and the particles may be counted as particles smaller than the actual size.
上水分野では、クリプトスポリジウム相当径の４〜６μｍの粒子を監視することと、前記クリプトスポリジウムや浄水中にしばしば含まれる藻類は、校正に用いる標準粒子より屈折率が水に近いので、散乱光方式のパルス信号が小さくなるという理由から、主に光遮断方式が採用されている。
前記半導体レーザを用いた濁度計は、従来にない低濁度を安定して測定できるという利点を持つが、その反面、以下に述べる問題がある。
その問題とは、半導体レーザを用いた濁度計や微粒子カウンタの光ビームは強度分布を持っており、微粒子の光ビーム中を通る位置によって、散乱光パルス、あるいは光遮断パルスの波高値が異なり、同じ大きさの微粒子であっても異なる粒径としてカウントされることである。半導体分野に使用する測定器では、光ビームの強度分布が平坦な部分のみを通過するように流路を絞る工夫がされているが、上水分野に使用する測定器では、流路が目詰まりを起こす可能性があるので、１ｍｍ角程度までにしか小さくできない。そこで、通常は光ビーム強度分布をガウシァン分布などに仮定することにより、カウント値に補正をかけている。この補正は微粒子数が多いときは有効だが、数が少なくなると精度が悪くなる。特に上水分野における１０μｍ以上の微粒子数は非常に少ないので、光ビームの強度分布補正が行なわれた微粒子個数はばらつきが大きくなる。
The turbidimeter using the semiconductor laser has the advantage of being able to stably measure low turbidity, which is not conventional, but has the following problems.
The problem is that the light beam of a turbidimeter or particle counter using a semiconductor laser has an intensity distribution, and the peak value of the scattered light pulse or the light blocking pulse differs depending on the position passing through the particle light beam. In other words, even fine particles of the same size are counted as different particle sizes. Measuring instruments used in the semiconductor field have been devised to narrow the flow path so that the intensity distribution of the light beam only passes through a flat part, but in measuring instruments used in the water supply field, the flow path is clogged. Can be reduced only to about 1 mm square. Therefore, the count value is usually corrected by assuming that the light beam intensity distribution is Gaussian distribution or the like. This correction is effective when the number of fine particles is large, but accuracy decreases when the number is small. In particular, since the number of fine particles of 10 μm or more in the water supply field is very small, the number of fine particles subjected to light beam intensity distribution correction varies greatly.
上記の問題を解決するため、請求項１から５の発明は半導体レーザから出力される光ビームを均一な強度分布に変換する光学素子を用いることとする。
請求項６、７の発明は、請求項１の光学素子において、均一な強度分布に光ビームを整形するための溝を刻んだホログラムを使用することとする。
請求項１の発明は、光源に半導体レーザを用いて光ビームを試料水に向けて照射し、試料水中の微粒子による散乱光または光遮断を光電変換素子で電気信号に変換し、微粒子の散乱光パルス信号または光遮断パルス信号に基づいて、粒径区分ごとに試料水中の微粒子の個数濃度を求め、さらに、前記微粒子の個数濃度に対して粒径区分ごとに個別の係数を乗じて試料水の濁度を求める濁度および微粒子の測定方法において、強度分布が均一でない半導体レーザからの光ビームを、均一な強度分布に変換する光学素子によって半導体レーザからの照射された光ビームの強度分布を均一にする濁度および微粒子の測定方法であることを特徴とする。
In order to solve the above problems, the inventions according to claims 1 to 5 use an optical element that converts a light beam output from a semiconductor laser into a uniform intensity distribution.
The inventions of claims 6 and 7 use a hologram in which grooves for shaping a light beam in a uniform intensity distribution are engraved in the optical element of claim 1.
According to the first aspect of the present invention, a semiconductor laser is used as a light source to irradiate a light beam toward the sample water, and the scattered light or light blockage caused by the fine particles in the sample water is converted into an electrical signal by the photoelectric conversion element. Based on the pulse signal or the light blocking pulse signal, the number concentration of the fine particles in the sample water is obtained for each particle size category, and the sample water is further multiplied by an individual coefficient for each particle size category to the number concentration of the fine particles. In the method for measuring turbidity and fine particles to obtain turbidity, the intensity distribution of the light beam emitted from the semiconductor laser is made uniform by an optical element that converts the light beam from the semiconductor laser with a non-uniform intensity distribution into a uniform intensity distribution. It is a method for measuring turbidity and fine particles.
請求項２の発明は、光ビームを試料水に向けて照射する半導体レーザを用いた光源と、前記の光ビームにより試料水中の微粒子によって散乱光または光遮断を光電変換素子で電気信号に変換する光電変換手段と、微粒子の散乱光パルス信号または光遮断パルス信号に基づいて、粒径区分ごとに試料水中の微粒子の個数濃度を求める微粒子の計数手段と、さらに、前記微粒子の個数濃度に対して粒径区分ごとに個別の係数を乗じて試料水の濁度を求める手段とを備えた濁度および微粒子の測定装置において、強度分布が均一でない半導体レーザからの光ビームを、均一な強度分布に変換する光学素子によって半導体レーザの照射された光ビームの強度分布を均一にする手段を備えた濁度および微粒子の測定装置であることを特徴とする。 According to a second aspect of the present invention, a light source using a semiconductor laser that irradiates a sample water with a light beam and the light beam converts scattered light or light blocking into an electrical signal by a photoelectric conversion element by fine particles in the sample water. A photoelectric conversion means, a fine particle counting means for determining the number concentration of the fine particles in the sample water for each particle size classification based on the scattered light pulse signal or the light blocking pulse signal of the fine particles; In a turbidity and fine particle measurement device equipped with a means for determining the turbidity of sample water by multiplying individual coefficients for each particle size category, a light beam from a semiconductor laser with a non-uniform intensity distribution is converted into a uniform intensity distribution. It is a turbidity and fine particle measuring device provided with means for making the intensity distribution of a light beam irradiated by a semiconductor laser uniform by an optical element to be converted.
請求項３の発明は、請求項２記載の濁度および微粒子の測定装置において、前記光学素子は、光強度分布がガウシァン型である平行光を均一な強度分布を有する平行光に変換する光学素子を用い、半導体レーザから照射された発散光を、コリメートレンズで平行光とした後、前記光学素子によって均一強度分布の光ビームに変換することを特徴とする。
請求項４の発明は、請求項２記載の濁度および微粒子の測定装置において、前記光学素子は、光強度分布がガウシァン型である発散光を均一な強度分布を有する平行光に変換する光学素子を用い、半導体レーザから照射された発散光を前記光学素子により、均一強度分布を有する平行光に変換することを特徴とする。
According to a third aspect of the present invention, in the turbidity and fine particle measuring apparatus according to the second aspect, the optical element is an optical element that converts parallel light having a Gaussian light intensity distribution into parallel light having a uniform intensity distribution. The diverging light emitted from the semiconductor laser is converted into parallel light by a collimator lens, and then converted into a light beam having a uniform intensity distribution by the optical element.
According to a fourth aspect of the present invention, in the turbidity / fine particle measuring apparatus according to the second aspect, the optical element converts divergent light having a Gaussian light intensity distribution into parallel light having a uniform intensity distribution. And diverging light irradiated from a semiconductor laser is converted into parallel light having a uniform intensity distribution by the optical element.
請求項５の発明は、請求項３、または４記載の濁度および微粒子の測定装置において、前記均一強度分布を有する平行光をシリンドリカルレンズによって、フロ─セル内の所定の位置における光軸に垂直な断面形状が長方形、あるいは楕円形状となるように集光し、前記集光された光ビームの長辺あるいは長軸の方向が、流路に垂直となるようにシリンドリカルレンズを設置することを特徴とする。 According to a fifth aspect of the present invention, in the turbidity and fine particle measuring apparatus according to the third or fourth aspect, the parallel light having the uniform intensity distribution is perpendicular to the optical axis at a predetermined position in the flow cell by a cylindrical lens. And a cylindrical lens is installed so that the long side or long axis direction of the condensed light beam is perpendicular to the flow path. And
さらに、請求項６の発明は、請求項２記載の濁度および微粒子の測定装置において、前記光学素子は、光強度分布がガウシァン型である平行光を、光軸に垂直な面の断面形状が所定の位置において長方形、あるいは楕円形状となるように整形し、少なくとも光軸を中心として長い辺の方向、あるいは長軸方向の強度分布が均一である偏平光とするホログラムを用い、半導体レーザから照射された発散光を、コリメートレンズで平行光とした後、前記ホログラムによって均一強度分布の偏平光ビームに変換することを特徴とする。 Further, the invention of claim 6 is the turbidity and fine particle measuring apparatus according to claim 2, wherein the optical element is configured to emit parallel light having a Gaussian light intensity distribution and a cross-sectional shape perpendicular to the optical axis. Irradiated from a semiconductor laser using a hologram that is shaped into a rectangular or elliptical shape at a predetermined position and is flat light that has a uniform intensity distribution in the direction of the long side or at least the long axis around the optical axis The divergent light is converted into parallel light by a collimator lens, and then converted into a flat light beam having a uniform intensity distribution by the hologram.
請求項７の発明は、請求項２記載の濁度および微粒子の測定装置において、前記光学素子は、光強度分布がガウシァン型である発散光を、光軸に垂直な面の断面形状が所定の位置において長方形、あるいは楕円形状となるように整形し、少なくとも光軸を中心として長い辺の方向、あるいは長軸方向の強度分布が均一である偏平光とするホログラムを用い、半導体レーザから照射された発散光を前記ホログラムによって均一強度分布の偏平光ビームに変換することを特徴とする。 According to a seventh aspect of the present invention, in the turbidity / fine particle measuring apparatus according to the second aspect, the optical element has a divergent light whose light intensity distribution is Gaussian type, and a cross-sectional shape of a surface perpendicular to the optical axis is predetermined. Shaped to be rectangular or elliptical at the position and irradiated from a semiconductor laser using a hologram that is flat light with a uniform intensity distribution in the direction of the long side or the long axis direction at least around the optical axis The diverging light is converted into a flat light beam having a uniform intensity distribution by the hologram.
本発明は微粒子および濁度の測定方法と、その装置にかかり、請求項１〜７の発明により、光源からの光ビームの強度分布を均一にすることで、流路を必要以上に狭めることなく、微粒子の検出粒径の精度を向上させることを可能とする。 The present invention relates to a method for measuring fine particles and turbidity and an apparatus therefor. According to the first to seventh aspects of the present invention, the intensity distribution of the light beam from the light source is made uniform so as not to narrow the flow path more than necessary. It is possible to improve the accuracy of the detected particle diameter of the fine particles.
以下に本発明の実施形態について詳細に説明する。
〔実施例１〕
本発明の請求項１〜３、５に関する実施例として、光遮断方式の光学系を図１に示す。図５は従来の光遮断方式の光学系であり、これら図１、５はフローセル８の流路に対して垂直で光軸を含む断面を記載してある。以下に詳細な内容を記述する。
Hereinafter, embodiments of the present invention will be described in detail.
[Example 1]
As an embodiment relating to claims 1 to 3 of the present invention, a light blocking optical system is shown in FIG. FIG. 5 shows a conventional light blocking optical system, and FIGS. 1 and 5 show a cross section perpendicular to the flow path of the flow cell 8 and including the optical axis. Details are described below.
従来の光遮断方式の光学系では、図５（ａ）の半導体レーザ１１から照射された発散光１１Ａはコリメートレンズ１２によって平行光とされ、シリンドリカルレンズ１３によって流路方向に集光される。光ビームの光軸１１Ｂに垂直でかつ、フローセル８の流路中央を含む直線８Ａの上における光ビームの強度分布は図５（ｂ）のようにガウシァン分布となり、同じ粒径の微粒子であっても、光ビームを通過する位置によって、光遮断パルスの波高値が異なってしまうという問題が生じる。通常は光ビームの強度分布がガウシァン分布であることを仮定して粒径区分ごとのカウント値を補正するが、微粒子個数濃度が少ない場合には、必ずしも正確な補正を行うことは出来ない。 In the conventional light blocking optical system, divergent light 11A emitted from the semiconductor laser 11 shown in FIG. 5A is converted into parallel light by the collimator lens 12 and condensed in the flow path direction by the cylindrical lens 13. The intensity distribution of the light beam on the straight line 8A perpendicular to the optical axis 11B of the light beam and including the flow path center of the flow cell 8 is Gaussian distribution as shown in FIG. However, there arises a problem that the peak value of the light blocking pulse varies depending on the position through which the light beam passes. Normally, the count value for each particle size classification is corrected on the assumption that the intensity distribution of the light beam is Gaussian distribution. However, when the particle number concentration is small, accurate correction cannot always be performed.
そこで、同じ粒径の微粒子であれば、光遮断パルスの波高値が同じ値になるようにすることを目的として、光強度分布がガウシァン型である平行光を均一な強度分布の平行光に変換する光学素子を用いた例が図１（ａ）である。半導体レーザ１１から照射された発散光１１Ａはコリメートレンズ１２によって平行光とされ、さらに光学素子１４によって均一な強度分布に変換された後、シリンドリカルレンズ１３によって流路方向に集光される。ここで、前記直線８Ａの上における光ビームの強度分布は図１（ｂ）のように均一な強度分布となり、同じ粒径の微粒子であれば、光ビームを通過する位置が異なっても、光遮断パルスの波高値は同じ値となる。前記光学素子１４としては、例えば特開平１１−２５８５４４記載の光ビームのスポット径を小さくすることを主な目的として提案された光学素子が適用可能である。 Therefore, in the case of fine particles with the same particle size, parallel light with a Gaussian light intensity distribution is converted into parallel light with a uniform intensity distribution in order to make the peak value of the light blocking pulse the same value. An example using the optical element is FIG. The divergent light 11A emitted from the semiconductor laser 11 is converted into parallel light by the collimating lens 12, and further converted into a uniform intensity distribution by the optical element 14, and then condensed by the cylindrical lens 13 in the flow path direction. Here, the intensity distribution of the light beam on the straight line 8A is a uniform intensity distribution as shown in FIG. 1B. The crest value of the cutoff pulse is the same value. As the optical element 14, for example, an optical element proposed mainly for the purpose of reducing the spot diameter of a light beam described in JP-A-11-258544 can be applied.
尚、本実施例では光遮断方式の光学系に、光強度分布がガウシァン型である平行光を均一な強度分布の平行光に変換する光学素子を適用したが、前方散乱光方式や側方散乱光方式の光学系に対しても適用可能である。
〔実施例２〕
本発明の請求項１、２、４、５に関する実施例として、光強度分布がガウシァン型である発散光を均一な強度分布の平行光に変換する光学素子を用いた例を図２に示す。
In this embodiment, an optical element that converts parallel light having a Gaussian light intensity distribution into parallel light having a uniform intensity distribution is applied to the light blocking optical system. The present invention can also be applied to an optical type optical system.
[Example 2]
As an embodiment relating to claims 1, 2, 4, and 5 of the present invention, FIG. 2 shows an example using an optical element that converts divergent light having a Gaussian light intensity distribution into parallel light having a uniform intensity distribution.
半導体レーザ１１から照射された発散光１１Ａは、光学素子１５によって均一な強度分布に変換され、シリンドリカルレンズ１３によって流路方向に集光される。ここで、前記直線８Ａの上における光ビームの強度分布は図１（ｂ）と同じく、均一な強度分布となる。本実施例の光学素子によれば、前記実施例２の光学素子と比較して、コリメートレンズが不要であり、部品点数が減るという有利な点がある。前記光学素子１５としては、例えば特開２０００−８９１６１号公報に記載の光ビームのスポット径を小さくすることを主な目的として提案された光学素子が適用可能である。 The divergent light 11 </ b> A emitted from the semiconductor laser 11 is converted into a uniform intensity distribution by the optical element 15 and condensed in the flow path direction by the cylindrical lens 13. Here, the intensity distribution of the light beam on the straight line 8A is a uniform intensity distribution as in FIG. According to the optical element of the present embodiment, the collimating lens is unnecessary and the number of parts is reduced as compared with the optical element of the second embodiment. As the optical element 15, for example, an optical element proposed mainly for the purpose of reducing the spot diameter of the light beam described in JP-A-2000-89161 can be applied.
尚、本実施例では光遮断方式の光学系に、光強度分布がガウシァン型である発散光を均一な強度分布の平行光に変換する光学素子を適用したが、前方散乱光方式や側方散乱光方式の光学系に対しても適用可能である。
〔実施例３〕
本発明の請求項１、２、６に関する実施例として、光強度分布がガウシァン型である平行光を、光軸に垂直な面の断面形状が所定の位置において長方形、あるいは楕円形状となるように整形し、少なくとも光軸を中心として長辺の方向、あるいは長軸の方向の強度分布が均一である偏平光とするホログラムを用いた例を図３に示す。
In this embodiment, an optical element that converts divergent light having a Gaussian light intensity distribution into parallel light having a uniform intensity distribution is applied to the optical system of the light blocking method. The present invention can also be applied to an optical type optical system.
Example 3
As an embodiment relating to claims 1, 2, and 6 of the present invention, parallel light having a Gaussian light intensity distribution is used so that the cross-sectional shape of the surface perpendicular to the optical axis is rectangular or elliptical at a predetermined position. FIG. 3 shows an example using a shaped hologram that is flattened light having a uniform intensity distribution in the direction of the long side or the direction of the long axis centered at least on the optical axis.
半導体レーザ１１から照射された発散光１１Ａはコリメートレンズ１２によって平行光とされ、さらにホログラム１６によってビームを整形し、前記直線８Ａの上における光ビームの強度分布を図１（ｂ）のように均一な強度分布とする。
尚、本実施例では光遮断方式の光学系に、光強度分布がガウシァン型である平行光を均一な強度分布の平行光に変換する光学素子を適用したが、前方散乱光方式や側方散乱光方式の光学系に対しても適用可能である。
〔実施例４〕
本発明の請求項１、２、７に関する実施例として、光強度分布がガウシァン型である発散光を、光軸に垂直な面の断面形状が所定の位置において長方形、あるいは楕円形状となるように整形し、少なくとも光軸を中心として長い辺の方向、あるいは長軸方向の強度分布が均一である偏平光とするホログラムを用いた例を図４に示す。
The divergent light 11A emitted from the semiconductor laser 11 is converted into parallel light by the collimator lens 12, and further shaped by the hologram 16, and the intensity distribution of the light beam on the straight line 8A is uniform as shown in FIG. With a strong intensity distribution.
In this embodiment, an optical element that converts parallel light having a Gaussian light intensity distribution into parallel light having a uniform intensity distribution is applied to the light blocking optical system. The present invention can also be applied to an optical type optical system.
Example 4
As an embodiment relating to claims 1, 2, and 7 of the present invention, divergent light having a Gaussian light intensity distribution is used so that the cross-sectional shape of the surface perpendicular to the optical axis is rectangular or elliptical at a predetermined position. FIG. 4 shows an example using a shaped hologram that is flattened light that has a uniform intensity distribution in the direction of the long side or the long axis direction at least about the optical axis.
半導体レーザ１１から照射された発散光１１Ａは、ホログラム１７によってビームを整形し、直線８Ａ方向の光ビームの強度分布を図１ｂのように均一な強度分布とする。
尚、本実施例では光遮断方式の光学系に、光強度分布がガウシァン型である平行光を均一な強度分布の平行光に変換する光学素子を適用したが、前方散乱光方式や側方散乱光方式の光学系に対しても適用可能である。
The diverging light 11A irradiated from the semiconductor laser 11 shapes the beam by the hologram 17, and the intensity distribution of the light beam in the direction of the straight line 8A is made uniform as shown in FIG. 1b.
In this embodiment, an optical element that converts parallel light having a Gaussian light intensity distribution into parallel light having a uniform intensity distribution is applied to the light blocking optical system. The present invention can also be applied to an optical type optical system.
８： フローセル
８Ａ： 直線
１１： 半導体レーザ
１１Ａ： 発散光
１１Ｂ： 光ビームの光軸
１２： コリメートレンズ
１３： シリンドリカルレンズ
１４、１５： 光学素子
１６、１７： ホログラム
8: Flow cell
8A: Straight line
11: Semiconductor laser
11A: Divergent light
11B: Optical axis of light beam
12: Collimating lens
13: Cylindrical lens 14, 15: Optical element 16, 17: Hologram
Claims (7)
強度分布が均一でない半導体レーザからの光ビームを、均一な強度分布に変換する光学素子によって半導体レーザからの照射された光ビームの強度分布を均一にすることを特徴とする濁度および微粒子の測定方法。 Using a semiconductor laser as the light source, irradiate the sample water with a light beam, convert the scattered light or light blocking by the microparticles in the sample water into an electrical signal with a photoelectric conversion element, and scatter light pulse signal or light blocking pulse signal of the microparticles Based on the above, the number concentration of fine particles in the sample water is determined for each particle size category, and the turbidity for determining the turbidity of the sample water by multiplying the number concentration of the fine particles by an individual coefficient for each particle size category and In the measurement method of fine particles,
Measurement of turbidity and fine particles characterized in that the intensity distribution of the light beam emitted from the semiconductor laser is made uniform by an optical element that converts the light beam from the semiconductor laser having a non-uniform intensity distribution into a uniform intensity distribution. Method.
強度分布が均一でない半導体レーザからの光ビームを、均一な強度分布に変換する光学素子によって半導体レーザの照射された光ビームの強度分布を均一にする手段を備えたことを特徴とする濁度および微粒子の測定装置。 A light source using a semiconductor laser that irradiates the sample water with a light beam; photoelectric conversion means for converting scattered light or light blocking into an electrical signal by a photoelectric conversion element by the fine particles in the sample water by the light beam; Based on the scattered light pulse signal or the light blocking pulse signal, the fine particle counting means for obtaining the number concentration of the fine particles in the sample water for each particle size category, and further, individually for each particle size category with respect to the number concentration of the fine particles. In a turbidity and fine particle measuring device equipped with a means for determining the turbidity of sample water by multiplying by a coefficient,
Turbidity characterized by comprising means for making the intensity distribution of the light beam irradiated by the semiconductor laser uniform by an optical element that converts the light beam from the semiconductor laser having a non-uniform intensity distribution into a uniform intensity distribution Measuring device for fine particles.
前記光学素子は、光強度分布がガウシァン型である平行光を均一な強度分布を有する平行光に変換する光学素子を用い、半導体レーザから照射された発散光を、コリメートレンズで平行光とした後、前記光学素子によって均一強度分布の光ビームに変換することを特徴とする濁度および微粒子の測定装置。 In the turbidity and fine particle measuring apparatus according to claim 2,
The optical element is an optical element that converts parallel light having a Gaussian light intensity distribution into parallel light having a uniform intensity distribution, and diverging light emitted from a semiconductor laser is converted into parallel light by a collimator lens. An apparatus for measuring turbidity and fine particles, wherein the optical element converts the light beam into a light beam having a uniform intensity distribution.
前記光学素子は、光強度分布がガウシァン型である発散光を均一な強度分布を有する平行光に変換する光学素子を用い、半導体レーザから照射された発散光を前記光学素子により、均一強度分布を有する平行光に変換することを特徴とする濁度および微粒子の測定装置。 In the turbidity and fine particle measuring apparatus according to claim 2,
The optical element uses an optical element that converts divergent light having a Gaussian light intensity distribution into parallel light having a uniform intensity distribution, and the divergent light emitted from the semiconductor laser is converted into a uniform intensity distribution by the optical element. An apparatus for measuring turbidity and fine particles, which is converted into parallel light.
前記均一強度分布を有する平行光をシリンドリカルレンズによって、フロ─セル内の所定の位置における光軸に垂直な断面形状が長方形、あるいは楕円形状となるように集光し、前記集光された光ビームの長辺あるいは長軸の方向が、流路に垂直となるようにシリンドリカルレンズを設置することを特徴とする濁度および微粒子の測定装置。 In the turbidity and fine particle measuring device according to claim 3 or 4,
The collimated light having the uniform intensity distribution is condensed by a cylindrical lens so that the cross-sectional shape perpendicular to the optical axis at a predetermined position in the flow cell is rectangular or elliptical, and the condensed light beam A turbidity and fine particle measuring device, wherein a cylindrical lens is installed so that the direction of the long side or the long axis is perpendicular to the flow path.
前記光学素子は、光強度分布がガウシァン型である平行光を、光軸に垂直な面の断面形状が所定の位置において長方形、あるいは楕円形状となるように整形し、少なくとも光軸を中心として長い辺の方向、あるいは長軸方向の強度分布が均一である偏平光とするホログラムを用い、半導体レーザから照射された発散光を、コリメートレンズで平行光とした後、前記ホログラムによって均一強度分布の偏平光ビームに変換することを特徴とする濁度および微粒子の測定装置。 In the turbidity and fine particle measuring apparatus according to claim 2,
The optical element shapes parallel light having a Gaussian light intensity distribution so that a cross-sectional shape of a surface perpendicular to the optical axis is rectangular or elliptical at a predetermined position, and is long at least around the optical axis Using a hologram that produces flattened light with uniform intensity distribution in the direction of the side or in the long axis direction, divergent light emitted from a semiconductor laser is converted into parallel light by a collimator lens, and then the uniform intensity distribution is flattened by the hologram. An apparatus for measuring turbidity and fine particles, which is converted into a light beam.
前記光学素子は、光強度分布がガウシァン型である発散光を、光軸に垂直な面の断面形状が所定の位置において長方形、あるいは楕円形状となるように整形し、少なくとも光軸を中心として長い辺の方向、あるいは長軸方向の強度分布が均一である偏平光とするホログラムを用い、半導体レーザから照射された発散光を前記ホログラムによって均一強度分布の偏平光ビームに変換することを特徴とする濁度および微粒子の測定装置。 In the turbidity and fine particle measuring apparatus according to claim 2,
The optical element shapes divergent light having a Gaussian light intensity distribution so that a cross-sectional shape of a surface perpendicular to the optical axis is rectangular or elliptical at a predetermined position, and is long at least around the optical axis. A hologram having flat light with uniform intensity distribution in the side direction or major axis direction is used, and diverging light irradiated from a semiconductor laser is converted into a flat light beam with uniform intensity distribution by the hologram. Turbidity and particulate measuring device.
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