JPS5960341A - Method for measuring particle size distribution using laser diffraction image - Google Patents
Method for measuring particle size distribution using laser diffraction imageInfo
- Publication number
- JPS5960341A JPS5960341A JP57171646A JP17164682A JPS5960341A JP S5960341 A JPS5960341 A JP S5960341A JP 57171646 A JP57171646 A JP 57171646A JP 17164682 A JP17164682 A JP 17164682A JP S5960341 A JPS5960341 A JP S5960341A
- Authority
- JP
- Japan
- Prior art keywords
- diffraction image
- particle size
- size distribution
- particles
- electric signal
- 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.)
- Granted
Links
- 239000002245 particle Substances 0.000 title claims abstract description 41
- 238000000034 method Methods 0.000 title claims description 7
- 238000005314 correlation function Methods 0.000 claims abstract description 7
- 238000006243 chemical reaction Methods 0.000 claims description 4
- 230000003287 optical effect Effects 0.000 abstract description 7
- 230000009466 transformation Effects 0.000 abstract 1
- 238000005259 measurement Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000003908 quality control method Methods 0.000 description 2
- 230000005856 abnormality Effects 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- 238000000149 argon plasma sintering Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
- G01N15/02—Investigating particle size or size distribution
- G01N15/0205—Investigating particle size or size distribution by optical means, e.g. by light scattering, diffraction, holography or imaging
- G01N15/0211—Investigating a scatter or diffraction pattern
Abstract
Description
【発明の詳細な説明】
本発明は、レーザー回折像を用いる粒度分布の測定法に
関する。粒子の大きさやその分布状態を計測することは
、粉粒体工学、細胞学、大気汚染計測のみならず、鉄鉱
、食品、薬品などの製造業においても、品質管理、製造
工程制御などにとって極めて重要な問題となっている。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring particle size distribution using a laser diffraction image. Measuring the size of particles and their distribution is extremely important not only for particle engineering, cytology, and air pollution measurement, but also for quality control and manufacturing process control in manufacturing industries such as iron ore, food, and pharmaceuticals. This has become a serious problem.
従来、レーザー光を用いた粒度分布の測定方法としては
、光散乱分光法や、レーザー光の回析像から行列計算に
より求める方法などがあったが、広範囲にわたって、連
読的な粒度分布を導出するのは、原理的に不可能であっ
た。Conventionally, methods for measuring particle size distribution using laser light include light scattering spectroscopy and methods for determining it by matrix calculation from a diffraction image of laser light, but it is now possible to derive a continuous particle size distribution over a wide range of areas. It was impossible in principle to do so.
本発明は上記に鑑みなされたものであって、レーザー回
析像を用いて連続的な粒度分布を測定する方法を提供す
ることを目的とする。The present invention has been made in view of the above, and an object of the present invention is to provide a method for measuring continuous particle size distribution using a laser diffraction image.
この目的は、次の工程によって達成される。This objective is achieved by the following steps.
■ ランダムに分布している粒子にレーザー光を投射し
て粒子の回析像をつくる。■ Create a diffraction image of particles by projecting laser light onto randomly distributed particles.
■ この回析像の光強度の空間分布を表わす電気
ａは粒子半径、ρは回折像面上の空間座標、Ｎ（ａ）は
粒度分布は定数）をつくる。(2) Electricity a representing the spatial distribution of light intensity of this diffraction image is the particle radius, ρ is the spatial coordinate on the diffraction image surface, and N(a) is the particle size distribution, which is a constant).
〔０，∞〕の範囲で積分し、新たな変数（こゝで、Ａ＝
ａ２）を
つくる。Integrate over the range [0, ∞] and create a new variable (here, A=
Make a2).
Ｕ（Ｔ）はステップ関数）をつくる。U(T) is a step function).
■ 上記のＦ（Ｔ）ｈ（Ｔ）との相互相関関数を求めて
Ｎ（ａ）を得る。(2) Find the cross-correlation function with F(T)h(T) above to obtain N(a).
以下、添付図により本発明を説明する。第１図は本発明
の測定法の実施に用いる装置の一例であって、被測定粒
子の回析像を得るための光学系ならびに信号処理系を示
す。The present invention will be explained below with reference to the accompanying drawings. FIG. 1 is an example of an apparatus used to carry out the measurement method of the present invention, and shows an optical system and a signal processing system for obtaining a diffraction image of a particle to be measured.
１．はコヒーレントな光を発する光源たとえばレーザー
装置であり、２．は光を平行光とする光学系、３．は粒
子がランダムに分布する被測定面であり、４．はフーリ
エ変換レンズであり、５は粒子の回折像（フーリエ変換
像）が得られる面である。６．は得られた回折像の光強
度を電気信号に変換する光電変換装置たとえばダイオー
ドアレイ、ＴＶカメラ等であり、７．は電気信号を処理
する装置たとえばコンピュータ等である。1. 2. is a light source that emits coherent light, such as a laser device; 2. 3. is an optical system that converts light into parallel light; is a surface to be measured on which particles are randomly distributed; 4. is a Fourier transform lens, and 5 is a surface from which a diffraction image (Fourier transform image) of particles is obtained. 6. 7. is a photoelectric conversion device that converts the light intensity of the obtained diffraction image into an electrical signal, such as a diode array or a TV camera; is a device that processes electrical signals, such as a computer.
いま、自然状態にある半径ａの粒子がもつ粒度分布Ｎ（
ａ）を、粉粒体工学で一般に用いられている次式の対数
正規分布（ｌｏｇａｒｉｔｈｍｉｃ ｎｏｒｍａｌ ｄ
ｉｓｔ−ｒｉｂｕｔｉｏｎ）で仮定すると、
得られる粒子の回析像の光強度を表わす電気信号ｌ（ρ
）は、
（ただし、ρは回析像面上の空間座標、ｋは定数）で表
わされ、これは第２図に示す関係曲線となる。Now, the particle size distribution N(
a) is defined by the logarithmic normal distribution (logarithmic normal d
ist-ribution), the electric signal l(ρ
) is expressed as (where ρ is a spatial coordinate on the diffraction image plane and k is a constant), which becomes the relationship curve shown in FIG.
の範囲で積分する、新たな関数Ｆ（Ｔ）は次式（たゞし
、Ａ＝ａ２）
で表わされ、これは第３図に示す関係曲線となる数）を
３回微分して求めたオペレータｈ（Ｔ）を示し、で表わ
される。The new function F(T), which is integrated over the range of The operator h(T) is expressed as .
そして、Ｆ（Ｔ）とｈ（Ｔ）の相互相関関数、すなわち
第３図と第４図との相互相関関数を求めて、粒度分布Ｎ
（ａ）を求めると、第５図の粒度分布曲線が得られる。Then, the cross-correlation function of F(T) and h(T), that is, the cross-correlation function of FIGS. 3 and 4, is determined, and the particle size distribution N
When (a) is determined, the particle size distribution curve shown in FIG. 5 is obtained.
図中、イは初めに仮定した（１）式の分布曲線であり、
ロが上記処理からなる本発明により求めた分布曲線であ
る。一部分を除いて両分布曲線が一致しており、本発明
によれば連続的な粒度分布を極めて精度良く測定できる
ことが理解される。In the figure, A is the distribution curve of equation (1) assumed at the beginning,
B is a distribution curve obtained by the present invention comprising the above processing. The two distribution curves coincide with each other except for a portion, and it is understood that according to the present invention, a continuous particle size distribution can be measured with extremely high accuracy.
なお、（１）式で表わされる粒度分布を例にとって説明
したが、第１図の装置を用いる場合について説明する。Although the particle size distribution expressed by equation (1) has been explained as an example, the case where the apparatus shown in FIG. 1 is used will now be explained.
先ず、ランダムに分布している粒子にレーザー装置１及
び光学系２によりレーザー光を投射し、フーリエ変換レ
ンズ４を介して面５上に得られる粒子の回析像を、光電
変換装置６で光強度を表わす電気信号ｌ（ρ）に変換す
る。次いで処埋装置７を用いて、電気信号ｌ（ρ）を上
記（２）、（３）、（４）式に従って処理し、（３）、
（４）式で表わされるＦ（Ｔ）とｈ（Ｔ）の相互相関関
数をとって、粒度分布Ｎ（ａ）を求めればよい。First, a laser device 1 and an optical system 2 project a laser beam onto randomly distributed particles, and a diffraction image of the particles obtained on a surface 5 through a Fourier transform lens 4 is converted into an optical image by a photoelectric conversion device 6. It is converted into an electrical signal l(ρ) representing the intensity. Next, using the processing device 7, the electric signal l(ρ) is processed according to the above equations (2), (3), and (4), and (3),
The particle size distribution N(a) may be obtained by taking the cross-correlation function of F(T) and h(T) expressed by equation (4).
以上説明したように、本発明はレーザー光の回析像を用
いるために、粒子の直径が光の半波長程度から、第１図
の光学系２、４を変えることにより、数ｃｍ程度までの
粒子の粒度分布を測定できる。As explained above, since the present invention uses a diffraction image of laser light, the diameter of the particles can be changed from about half the wavelength of light to about several centimeters by changing the optical systems 2 and 4 in FIG. The particle size distribution of particles can be measured.
また、サンプルに特別な加工を必要としないため、製産
工程への導入が容易にでき、オンラインの計測ができ計
算機処理の高速化により実時間の測定が可能となる。し
たがって本発明は、粒度分布が連続的に精度良く求まる
ことゝ相俟って、製造品の異常検出や、原料の最適パラ
メータの決定など、品質管理、工程管理の迅速化、高精
度化に寄与することができる。In addition, since no special processing is required on the sample, it can be easily introduced into the manufacturing process, and online measurement is possible, making real-time measurement possible due to faster computer processing. Therefore, the present invention allows the particle size distribution to be determined continuously and with high precision, which together contributes to speeding up and increasing the accuracy of quality control and process control, such as detecting abnormalities in manufactured products and determining optimal parameters for raw materials. can do.
第１図は本発明に用いる装置の光学系と信号処理系の一
例を示す。第２図は本発明を説明するために用いた仮定
した粒度分布から成る粒子の回析像強度を表わすグラフ
、第３図は第２図に対して
第４図は本発明に用いるオペレータｈ（Ｔ）を示すグラ
フ。第５図は第３図と第４図との相互相関関数を求めて
得られた粒度分布Ｎ（ａ）を示すグラフ。
図中の符号：１−−−レーザー装置、２−−−光学系、
３−−−被測定面、４−−−フーリエ変換レンズ、５−
−−回析像が得られる面、６−−−光電変換装置、７−
−−電気信号変換装置。FIG. 1 shows an example of an optical system and a signal processing system of an apparatus used in the present invention. FIG. 2 is a graph showing the intensity of the diffraction image of particles having the assumed particle size distribution used to explain the present invention. Graph showing T). FIG. 5 is a graph showing the particle size distribution N(a) obtained by calculating the cross-correlation function between FIG. 3 and FIG. 4. Codes in the figure: 1---Laser device, 2---Optical system,
3---Measurement surface, 4---Fourier transform lens, 5-
--Surface from which a diffraction image is obtained, 6--Photoelectric conversion device, 7-
--Electrical signal converter.
Claims (1)
をつくり、この回析像の光強度の空間分布を表わす電気
信号 （こゝで、ａは粒子半径、ρは回析像が表われる空間の
一次変数、Ｎ（ａ）は粒度分布、ｋは定数）をつくり、
この電気信号を次式に従って処理して粒度分布Ｎ（ａ）
を決定することを特徴とするレーザー回折像を用いる粒
度分布測定法。 積分し、ａ２＝Ａなる変数変換を行ってを導出し、オペ
レータ （こゝでＵ（Ｔ）はステップ関数）と Ｆ（Ｔ）との相関関数を導出してＮ（ａ）を求める。[Claims] Laser light is projected onto distributed particles to create a diffraction image of the particles, and an electric signal representing the spatial distribution of the light intensity of this diffraction image (here, a is the particle radius, ρ is the primary variable of the space in which the diffraction image appears, N(a) is the particle size distribution, and k is a constant),
This electric signal is processed according to the following formula to obtain the particle size distribution N(a)
A particle size distribution measuring method using a laser diffraction image, which is characterized by determining the . Integrate, perform variable conversion such that a2=A, and derive N(a) by deriving the correlation function between the operator (here, U(T) is a step function) and F(T).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57171646A JPS5960341A (en) | 1982-09-30 | 1982-09-30 | Method for measuring particle size distribution using laser diffraction image |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57171646A JPS5960341A (en) | 1982-09-30 | 1982-09-30 | Method for measuring particle size distribution using laser diffraction image |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5960341A true JPS5960341A (en) | 1984-04-06 |
| JPH032251B2 JPH032251B2 (en) | 1991-01-14 |
Family
ID=15927066
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57171646A Granted JPS5960341A (en) | 1982-09-30 | 1982-09-30 | Method for measuring particle size distribution using laser diffraction image |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5960341A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62175645A (en) * | 1986-01-30 | 1987-08-01 | Nikkiso Co Ltd | Online automatic powdery and granular material grain size analyzer |
| JPH03115949A (en) * | 1989-09-29 | 1991-05-16 | Shimadzu Corp | Measuring method for distribution of particle size |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS535937A (en) * | 1976-07-02 | 1978-01-19 | Ibm | Firsttin firsttout memory |
| JPS5544900A (en) * | 1978-09-23 | 1980-03-29 | Stamicarbon | Stretching method for netted material web and its stretching device |
-
1982
- 1982-09-30 JP JP57171646A patent/JPS5960341A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS535937A (en) * | 1976-07-02 | 1978-01-19 | Ibm | Firsttin firsttout memory |
| JPS5544900A (en) * | 1978-09-23 | 1980-03-29 | Stamicarbon | Stretching method for netted material web and its stretching device |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62175645A (en) * | 1986-01-30 | 1987-08-01 | Nikkiso Co Ltd | Online automatic powdery and granular material grain size analyzer |
| JPH03115949A (en) * | 1989-09-29 | 1991-05-16 | Shimadzu Corp | Measuring method for distribution of particle size |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH032251B2 (en) | 1991-01-14 |
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