JP2575469B2 - Surface inspection equipment - Google Patents
Surface inspection equipmentInfo
- Publication number
- JP2575469B2 JP2575469B2 JP16084188A JP16084188A JP2575469B2 JP 2575469 B2 JP2575469 B2 JP 2575469B2 JP 16084188 A JP16084188 A JP 16084188A JP 16084188 A JP16084188 A JP 16084188A JP 2575469 B2 JP2575469 B2 JP 2575469B2
- Authority
- JP
- Japan
- Prior art keywords
- laser beam
- scanning
- shutter
- diffracted light
- photoelectric converter
- 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.)
- Expired - Fee Related
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
- G01N21/8901—Optical details; Scanning details
Landscapes
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
Description
【発明の詳細な説明】 [発明の目的] (産業上の利用分野) この発明は、鉄、アルミニウム、ステンレスまたは
紙、フィルムなど、金属、非金属を問わずそれらの帯状
(シート状)物体の表面を検査する装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a metal (non-metal) such as iron, aluminum, stainless steel or paper, film, and the like for a band-shaped (sheet-shaped) object thereof. The present invention relates to a device for inspecting a surface.
(従来の技術) 第3図は、現在発明者等が表面検査のための標準方式
として用いている。TOSPECTOR700(商標)の構成を示す
図である。(Prior Art) FIG. 3 is used by the present inventors as a standard method for surface inspection. It is a figure showing the composition of TOSPECTOR700 (trademark).
図面において、1はレーザスキャナであり、レーザビ
ーム2を検査対象3の幅方向に走査する(走査線5)。
検査対象3は鉄、アルミニウム、ステンレスまたは紙、
フィルムなどの帯状の物質であって、レーザ光の走査方
向と直角方向4に走向している。レーザ光2の検査対象
3からの反射光は、表面の素地や、欠陥などに基づく微
細な凹凸により回折を生じる。この回折光の分布6は、
表面の上記微細構造によるが、例べば“スリキズ”のよ
うな検査対象3の走向方向に走る引かき疵では、正反射
光の左右両方向に疵に基づく回折光を生じる。この回折
光はレンズ7によるフーリエ変換作用に基づいて屈折さ
れ、光電変換器8の前面に設けられたマスク9上の、回
折角に応じた位置に集光される。すなわち、走査線5上
の任意の点Aおよび任意の点Bにおけるスリキズに対し
てその回折光のうち同じ回折角を持った回折光成分S1と
成分S3はマスク9の点D1に、一方回折光成分S2と成分S4
はマスク9上の点D2にそれぞれ集光される。なおマスク
9上の点Dは正反射光Sの集光位置である。In the drawing, reference numeral 1 denotes a laser scanner, which scans a laser beam 2 in a width direction of an inspection target 3 (scanning line 5).
The inspection target 3 is iron, aluminum, stainless steel or paper,
It is a band-like material such as a film, and runs in a direction 4 perpendicular to the scanning direction of the laser beam. The reflected light of the laser beam 2 from the inspection target 3 is diffracted by fine irregularities based on the surface texture or defects. The distribution 6 of the diffracted light is
According to the fine structure on the surface, a scratch such as “scratch” that runs in the running direction of the inspection target 3 generates diffracted light based on the scratch in both the left and right directions of the specularly reflected light. The diffracted light is refracted based on the Fourier transform effect of the lens 7 and is condensed on a mask 9 provided on the front surface of the photoelectric converter 8 at a position corresponding to the diffraction angle. That is, with respect to the scratch at the arbitrary point A and the arbitrary point B on the scanning line 5, the diffracted light components S1 and S3 having the same diffraction angle out of the diffracted light become the point D1 of the mask 9 while the diffracted light Component S2 and component S4
Are focused on a point D2 on the mask 9, respectively. A point D on the mask 9 is a condensing position of the regular reflection light S.
したがって、マスク9において、点D1,D2に相当する
位置の透過率を大きくしておけば、検査対象3上のスリ
キズを検出する事が出来る。なお光電変換器8は、例え
ば光電子増倍管等からなり、マスク9を介して入力する
回折光の光量を電気信号に変換する。図示はされていな
いが、光電変換器8による電気信号は、例えばマイクロ
コンピュータ等に入力され、予め決められた手順で信号
処理されてスリキズが認識される。なおこの装置では、
上述のスリキズのみならず、他の表面欠陥に対して適宜
マスク設計を行うことによって、その欠陥特有の回折光
を効率良く検出し、欠陥の存在を認識する事が出来る。Therefore, if the transmittance of the mask 9 at the position corresponding to the points D1 and D2 is increased, the scratch on the inspection target 3 can be detected. The photoelectric converter 8 includes, for example, a photomultiplier tube, and converts the amount of diffracted light input through the mask 9 into an electric signal. Although not shown, an electric signal from the photoelectric converter 8 is input to, for example, a microcomputer or the like, and is subjected to signal processing according to a predetermined procedure to recognize a scratch. In this device,
By appropriately designing a mask for not only the aforementioned scratches but also for other surface defects, it is possible to efficiently detect diffracted light specific to the defect and recognize the presence of the defect.
(発明が解決しようとする課題) 以上のように従来の表面検査装置では、レンズのフー
リエ変換作用を利用して回折光の静止パターンをマスク
面上に形成し、これを空間フィルタすることによって特
定の回折光成分を捉え、表面の欠陥を認識している。し
たがって、この装置ではフーリエ変換を行うレンズ7が
不可決であり、その結果レンズの物理的限界から走査範
囲を余り大きくすることが出来ない。そのため、幅広の
検査対象の場合は、図示するような検出ヘッドを多数平
行に使用し、幅全体をカバーする必要があり、装置全体
が大型化すると共にコストの上昇を招いていた。(Problems to be Solved by the Invention) As described above, in the conventional surface inspection apparatus, a stationary pattern of the diffracted light is formed on the mask surface by using the Fourier transform function of the lens, and this is specified by spatial filtering. To detect surface defects. Therefore, in this apparatus, the lens 7 for performing the Fourier transform is indeterminate, and as a result, the scanning range cannot be made too large due to the physical limit of the lens. Therefore, in the case of a wide inspection object, it is necessary to use a large number of detection heads as shown in parallel and cover the entire width, and the whole apparatus is increased in size and the cost is increased.
この発明は以上のような問題点を解決する目的で成さ
れたもので、幅広の検査対象に十分対応しえて、しかも
小型で製造コストの低い表面検査装置を提供するもので
ある。SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above problems, and it is an object of the present invention to provide a small and low-cost surface inspection apparatus which can sufficiently cope with wide inspection objects.
[発明の構成] (課題を解決するための手段) この発明では、上記課題を解決するために、長手方向
に走行する帯状の検査対象表面をレーザビームで幅方向
に走査し、レーザビームの走査方向と平行に設置した棒
状の光電変換器によって上記検査対象表面によるレーザ
光の反射光を検出し、検出信号を電気的に処理して上記
表面の状態を認識する表面検査装置において、 上記棒状光電変換器の入射面前面にそれぞれが独立し
て開閉制御される多数の小シャッターからなるシャッタ
ー列を配置すると共に、個々のシャッターをレーザー光
の走査と同期して独立して開閉制御する手段を設けたこ
とを要旨とする。[Means for Solving the Problems] In the present invention, in order to solve the above problems, a belt-like surface to be inspected traveling in a longitudinal direction is scanned in a width direction with a laser beam, and scanning with a laser beam is performed. In a surface inspection apparatus for detecting reflected light of laser light from the surface to be inspected by a rod-shaped photoelectric converter installed in parallel with the direction and electrically processing a detection signal to recognize the state of the surface, A shutter array consisting of a large number of small shutters, each of which is independently controlled to open and close, is arranged on the front surface of the entrance surface of the converter, and means for independently controlling the opening and closing of each shutter in synchronization with laser beam scanning is provided. The gist is that
(作用) 検査対象表面のある特定の欠陥による反射回折光は、
その欠陥に特有のパターンを有する。従ってレーザビー
ムの位置と、シャッター列におけるレーザビームの反射
回折光の入射位置の小シャッターとの関係が特定される
ように、レーザビームの走査に同期して、この小シャッ
ターの開成をシャッター列上で順次走査して行う。この
ようにすることによって、レーザビームが走査線上でど
のような位置に来ようとも、その位置での反射回折光の
入射位置に相当する小シャッターは開成されていること
になる。従って棒状光電変換器は、常に欠陥による反射
回折光のみを検出する。(Operation) The reflected and diffracted light from a specific defect on the surface to be inspected is
It has a pattern specific to the defect. Therefore, the opening of the small shutter is synchronized with the scanning of the laser beam so that the relationship between the position of the laser beam and the small shutter at the incident position of the reflected and diffracted light of the laser beam in the shutter array is specified. The scanning is performed sequentially. By doing so, no matter where the laser beam comes on the scanning line, the small shutter corresponding to the incident position of the reflected diffracted light at that position is opened. Therefore, the rod-shaped photoelectric converter always detects only the reflected diffraction light due to the defect.
(実施例) 第1図はこの発明の1実施例かかる表面検査装置の要
部の構成を示す斜視図である。なお第1図の装置におい
て、第3図に示す装置と同一の符号は同様な構成部材を
示すので、重複した説明は省略する。(Embodiment) FIG. 1 is a perspective view showing a configuration of a main part of a surface inspection apparatus according to one embodiment of the present invention. In the apparatus shown in FIG. 1, the same reference numerals as those in the apparatus shown in FIG. 3 denote the same components, and a duplicate description will be omitted.
この装置では、図示のようにレーザスキャナ1と検査
対象3の位置関係および両者の走査方向は、第3図に示
したものと同じである。一方10はこの実施例の特徴を構
成するシャッター列であり、レーザ光の走査方向に平行
に配置された棒状光電変換器11の前面を被覆するように
設けられている。このシャッター列10は、その開閉が個
々に独立して制御される多数の小シャッター12、12・・
・の集合からなり、シャッター制御装置13によって開閉
制御されている。このシャッター列10は、例えば独立し
て電界が印加される小領域12、12・・・の集合である液
晶パネルであって、シャッター制御装置13によって各領
域の液晶の透過度を変化させて、シャッターとしての動
作を行うものであっても良い。In this apparatus, as shown, the positional relationship between the laser scanner 1 and the inspection object 3 and the scanning directions of both are the same as those shown in FIG. On the other hand, reference numeral 10 denotes a shutter array which constitutes a feature of this embodiment, and is provided so as to cover the front surface of the rod-shaped photoelectric converter 11 arranged in parallel to the scanning direction of the laser beam. This shutter array 10 has a large number of small shutters 12, 12.
The opening / closing is controlled by the shutter control device 13. The shutter row 10 is, for example, a liquid crystal panel that is a set of small areas 12, 12... To which an electric field is independently applied, and the shutter control device 13 changes the transmittance of the liquid crystal in each area, It may perform an operation as a shutter.
棒状光電変換器11は、検出すべき欠陥の回折光がもっ
とも顕著に現れる位置に置かれ、受光信号を電気信号に
変換して後段のマイクロコンピュータ等(図示せず)に
出力する。The rod-shaped photoelectric converter 11 is placed at a position where the diffracted light of the defect to be detected most remarkably appears, converts the received light signal into an electric signal, and outputs the electric signal to a microcomputer or the like (not shown) at the subsequent stage.
次に上記装置の動作を、検出すべき欠陥が検査対象の
走向方向と同じ方向の疵または圧延条痕である場合につ
いて説明する。Next, the operation of the above apparatus will be described for the case where the defect to be detected is a flaw or a rolling streak in the same direction as the running direction of the inspection object.
表面地肌上の各種の欠陥について回折光分布を調査、
研究した結果、走行方向と同じ方向の疵または圧延条痕
(いわゆるスリキズ)に起因する回折光は、入射点を頂
点とする円錐面に添って進むことが判明した。この円錐
面は第1図に鎖線14で示されている。入射点を原点Oに
取り、走査方向をx軸に、検査対象の3の走行方向をy
軸に、更に検査対象3への垂線をZ軸に取ると、レーザ
光の入射角θに対して上記円錐はy軸を中心軸とし頂角
は(π−2θ)となる。Investigate the diffraction light distribution for various defects on the surface background,
As a result of the study, it was found that diffracted light caused by flaws or rolling streaks (so-called scratches) in the same direction as the traveling direction proceeds along a conical surface having the incident point at the apex. This conical surface is shown in FIG. The incident point is set to the origin O, the scanning direction is set to the x-axis, and the traveling direction of the inspection target 3 is set to y.
When the perpendicular to the inspection object 3 is taken along the axis and the Z-axis is taken, the cone has the y-axis as the central axis and the apex angle becomes (π-2θ) with respect to the incident angle θ of the laser beam.
第2図は、各種のスリキズa,b,cに対して、上記円錐
の底面にスクリーンをおいて回折光によるパターンを観
察したものであり、図A,B,Cはそれぞれ疵a,b,cに対応し
ている。なお、検査対象の地肌はダル(表面微細構造に
方向性があまり無いもの)である。また、スリキズa,b,
cはx軸方向の断面を示し、aは左右対象な凹キズ断
面、b、cは左右非対称な凹キズ断面を示す。FIG. 2 shows a pattern observed by diffracted light with respect to various types of scratches a, b, and c with a screen placed on the bottom surface of the cone, and FIGS. A, B, and C show flaws a, b, and c, respectively. Corresponds to c. The background to be inspected is dull (the surface microstructure has little directionality). Also, scratches a, b,
c indicates a cross section in the x-axis direction, a indicates a left-right symmetric concave flaw cross section, and b and c indicate left / right asymmetric concave flaw cross sections.
図示するように各疵a,b,cに対する回折光パターンA,
B,Cはそれぞれ中心に正反射による回折パターンPを有
し、さらに上記円錐の底円に沿ってその一部に疵による
回折パターンSを有している。即ち左右対称なキズaで
は図Aに示すように左右対称な回折パターンSa,Saが生
じ、キズb,cでは片側にのみ強く表れる回折パターンSb,
Scが生じる。なお図B,Cにおいて反対側の回折パターン
は中心Pの回りに生じた地肌による回折光によって隠れ
ている。As shown in the figure, the diffracted light patterns A,
Each of B and C has a diffraction pattern P due to regular reflection at the center, and a diffraction pattern S due to flaws at a part thereof along the bottom circle of the cone. That is, as shown in FIG. A, a symmetrical diffraction pattern Sa, Sa occurs in the symmetrical flaw a, and a diffraction pattern Sb, which appears strongly on only one side in the flaws b, c.
Sc occurs. In FIGS. B and C, the diffraction pattern on the opposite side is hidden by the diffracted light by the background generated around the center P.
以上のようにして、検出しようとする欠陥に基づく回
折光パターンがわかると、キズによる回折光が最も顕著
に現れる位置、すなわち第2図の例では位置S(Sa,Sb,
Scを含む)を、シャッター列10を含む棒状光電変換器11
が横切るように、変換器11を位置決めする。レーザ光の
走査にともなって上記位置Sは移動するが、このときシ
ャッター制御装置13によって各小シャッター12、12・・
・の開閉を制御し、位置Sの移動にともなって対応する
小シャッターが開成するようにする。このようにして、
棒状光電変換器11には常に検出すべき欠陥の回折光がレ
ーザビームの走査と同期して効率よく入射するので、こ
の装置によって感度よく欠陥を検出できる。なお第2図
の例では、シャッター列10の、正反射光の入射位置を中
心とする左右対称な2個の位置のシャッター12、12が同
時に開成される。As described above, when the diffracted light pattern based on the defect to be detected is known, the position where the diffracted light due to the scratch appears most remarkably, that is, in the example of FIG. 2, the position S (Sa, Sb,
Sc), a rod-shaped photoelectric converter 11 including a shutter row 10
The transducer 11 is positioned so that The position S moves with the scanning of the laser beam. At this time, the small shutters 12, 12,.
The opening and closing of the shutter is controlled so that the corresponding small shutter is opened as the position S moves. In this way,
Since the diffracted light of the defect to be always detected efficiently enters the rod-shaped photoelectric converter 11 in synchronization with the scanning of the laser beam, the defect can be detected with high sensitivity by this device. In the example of FIG. 2, the shutters 12 and 12 at two symmetrical positions on the left and right of the shutter row 10 about the incident position of the specularly reflected light are simultaneously opened.
以上に示した実施例は、検出対象となる欠陥が1種類
の場合であったが、例えばレーザ光の走査速度及びシャ
ッター制御装置13によるシャッターの開閉制御を工夫す
ることによって、この装置を幾種類もの欠陥に対応しう
るようにすることができる。即ち、レーザの走査速度を
検査対象3の走行速度よりも十分に速くし、レーザビー
ムが検査対象の同一点を実質的に複数回走査するように
する。さらにレーザビームの第1回目の走査時に開成す
る小シャッターと第2回目の走査時に開成する小シャッ
ターの位置を検出対象となる欠陥に応じて変えることに
より、2種類の欠陥を検出する事が出来る。更に同様な
操作を第3回目,第4回目等の走査に対して行うことに
よって、異なる複数の欠陥を全て1回の検出対象の走査
時に効率よく検出する事が出来る。In the above-described embodiment, the type of defect to be detected is one type. However, for example, by devising the scanning speed of the laser beam and the opening / closing control of the shutter by the shutter control device 13, several types of this device can be used. Deficiencies can be dealt with. That is, the scanning speed of the laser is set sufficiently higher than the traveling speed of the inspection target 3 so that the laser beam scans the same point of the inspection target substantially plural times. Further, two types of defects can be detected by changing the positions of the small shutter opened during the first scanning of the laser beam and the small shutter opened during the second scanning according to the defect to be detected. . Further, by performing the same operation on the third and fourth scans, a plurality of different defects can be efficiently detected at the time of one scan of the detection target.
[発明の効果] 以上実施例を挙げて説明したように、この発明の表面
検査装置では、フーリエ変換作用の為の光学レンズを用
いる必要が無いので、棒状光電変換器は大きさの制限を
受けず、検査対象の幅に応じて十分に大きなものとする
事が出来る。そのため従来装置のように複数の検出ヘッ
ドを用いることなく、単一のヘッドで幅広の検査対象に
対応する事が出来、装置を小型化しうると共に製造コス
トの低下をはかる事が出来る。[Effects of the Invention] As described above with reference to the embodiments, in the surface inspection apparatus of the present invention, since it is not necessary to use an optical lens for a Fourier transform operation, the rod-shaped photoelectric converter is limited in size. Instead, it can be made sufficiently large according to the width of the inspection object. Therefore, a single head can be used for a wide inspection object without using a plurality of detection heads unlike the conventional apparatus, and the apparatus can be downsized and the manufacturing cost can be reduced.
第1図はこの発明の1実施例にかかる表面検査装置の要
部構成斜視図、第2図は検査対象表面の欠陥とそれに基
づく回折パターンを示す図、および第3図は従来の表面
検査装置の要部構成斜視図である。 1:レーザスキャナ、2:レーザビーム 3:検査対象、10:シャッター列 11:棒状光電変換器、12:小シャッター 13:シャッター制御装置FIG. 1 is a perspective view of a main part of a surface inspection apparatus according to an embodiment of the present invention, FIG. 2 is a view showing a defect on a surface to be inspected and a diffraction pattern based on the defect, and FIG. 3 is a perspective view of a main part configuration of FIG. 1: laser scanner, 2: laser beam 3: inspection object, 10: shutter array 11: rod-shaped photoelectric converter, 12: small shutter 13: shutter control device
Claims (1)
レーザビームで幅方向に走査し、レーザビームの走査方
向と平行に設置した棒状の光電変換器によって上記検査
対象表面によるレーザ光の反射光を検出し、検出信号を
電気的に処理して上記表面の状態を認識する表面検査装
置において、 上記棒状光電変換器の入射面前面にそれぞれが独立して
開閉制御される多数の小シャッターからなるシャッター
列を配置すると共に、個々の小シャッターをレーザ光の
走査と同期して独立して開閉制御する手段を設けたこと
を特徴とする表面検査装置。1. A belt-like surface to be inspected traveling in a longitudinal direction is scanned in a width direction by a laser beam, and a laser beam is reflected by the surface to be inspected by a rod-shaped photoelectric converter installed in parallel with the scanning direction of the laser beam. In a surface inspection device that detects light and electrically processes a detection signal to recognize the state of the surface, a plurality of small shutters, each of which is independently opened and closed on the front surface of the incident surface of the rod-shaped photoelectric converter, are controlled. A surface inspection apparatus comprising: a plurality of shutter arrays; and means for independently controlling the opening and closing of individual small shutters in synchronization with laser beam scanning.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16084188A JP2575469B2 (en) | 1988-06-30 | 1988-06-30 | Surface inspection equipment |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16084188A JP2575469B2 (en) | 1988-06-30 | 1988-06-30 | Surface inspection equipment |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH0212041A JPH0212041A (en) | 1990-01-17 |
JP2575469B2 true JP2575469B2 (en) | 1997-01-22 |
Family
ID=15723565
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP16084188A Expired - Fee Related JP2575469B2 (en) | 1988-06-30 | 1988-06-30 | Surface inspection equipment |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2575469B2 (en) |
-
1988
- 1988-06-30 JP JP16084188A patent/JP2575469B2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
JPH0212041A (en) | 1990-01-17 |
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