JPS62223654A - Surface defect detector - Google Patents
Surface defect detectorInfo
- Publication number
- JPS62223654A JPS62223654A JP61067898A JP6789886A JPS62223654A JP S62223654 A JPS62223654 A JP S62223654A JP 61067898 A JP61067898 A JP 61067898A JP 6789886 A JP6789886 A JP 6789886A JP S62223654 A JPS62223654 A JP S62223654A
- Authority
- JP
- Japan
- Prior art keywords
- reflected light
- light
- output
- signal
- comparator
- 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
- 230000007547 defect Effects 0.000 title claims abstract description 38
- 238000001514 detection method Methods 0.000 claims abstract description 21
- 230000007423 decrease Effects 0.000 claims description 13
- 239000002184 metal Substances 0.000 abstract description 19
- 230000004069 differentiation Effects 0.000 abstract description 3
- 230000003287 optical effect Effects 0.000 description 11
- 238000010586 diagram Methods 0.000 description 5
- 239000000428 dust Substances 0.000 description 3
- 108091008695 photoreceptors Proteins 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 230000031700 light absorption Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Landscapes
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
この発明は、金属板などの被検査体表面における疵など
の欠陥を検出する表面欠陥検出装置に関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a surface defect detection device for detecting defects such as scratches on the surface of an object to be inspected such as a metal plate.
（従来の技術とその問題点）
この種の表面欠陥検出装置として、被検査体表面にレー
ザビームを照射してこれを光走査し、正常部と欠陥部と
の反射特性の違いから表面の欠陥を検出するようにした
ものが従来より広く用いられている。そして、このよう
な装置では、本来無害な汚れなどと区別して欠陥のみを
検出する機能が必要とされる。(Conventional technology and its problems) This type of surface defect detection device irradiates the surface of the object to be inspected with a laser beam and scans it with light, detecting surface defects by detecting differences in reflection characteristics between normal and defective areas. Detectors have been widely used in the past. In addition, such a device requires a function to detect only defects, distinguishing them from dirt and the like, which are originally harmless.
このような機能を有する従来装置の一例（特開昭５８−
２６２５２号公報）の概略図を第４図に示し、その装置
の出力波形を第５図に示す。この装置では、レーザ光源
１より出されたレーザビーム２をコリメータ３を経て回
転ミラー４で反射させ、その反射光により被検査体とし
ての金属板５の表面を、その幅方向に向けて光走査する
ように構成されている。そして、上記光走査により金属
板５の表面で反射する反射光のうち正反射光を一方の受
光器６で受光し、また上記反射光のうち乱反射光を別の
受光器７で受光する。次に、各受光器６．７から、それ
ぞれの受光子に応じて得られる充電変換出力ａ、ｂを、
アンプ８，９でそれぞれ増幅した後、アブログ演算回路
１０において後述する演算処理を行ない、それによって
表面汚れによる出力成分を消去する。さらに、このよう
にして得られた演算出力は次段の微分処理回路１１に送
るように構成されている。An example of a conventional device having such a function (Japanese Unexamined Patent Publication No. 1983-
26252) is shown in FIG. 4, and the output waveform of the device is shown in FIG. In this device, a laser beam 2 emitted from a laser light source 1 is reflected by a rotating mirror 4 through a collimator 3, and the surface of a metal plate 5 as an object to be inspected is optically scanned in the width direction by the reflected light. is configured to do so. Of the reflected light reflected on the surface of the metal plate 5 by the optical scanning, one light receiver 6 receives the specularly reflected light, and another light receiver 7 receives the diffusely reflected light among the reflected light. Next, charge conversion outputs a and b obtained from each photoreceptor 6.7 according to each photoreceptor are
After being amplified by the amplifiers 8 and 9, the arithmetic processing circuit 10 performs arithmetic processing, which will be described later, thereby erasing the output component due to surface dirt. Further, the calculation output obtained in this manner is configured to be sent to the next-stage differential processing circuit 11.
上記の装置において、金ぶ板５表面に第５図（Ａ）で示
すように光吸収性を９する汚れ１２が存在すると、第５
図（Ｂ）に示すように正反射光用受光器６の出力ａには
その汚れ１２に対応する低レベル信Ｆ３ ａ １が生じ
る。一方、第５図（Ｃ）に示すように乱反射光用受光器
７の出力ｂにも汚れ１２に対応する低レベル信号ｂ１が
生じる。このため、第４図のアナログ演算回路１０にお
いて双方の差をとることによって得られる演算出力Ｃで
は、第５図（Ｄ）に示ツにうに、これらの信号ａ１．ｂ
１が相殺されて消去される。In the above device, if there is dirt 12 on the surface of the metal plate 5, which has a light absorption of 9, as shown in FIG.
As shown in Figure (B), a low level signal F3 a 1 corresponding to the dirt 12 is generated at the output a of the specularly reflected light receiver 6 . On the other hand, as shown in FIG. 5(C), a low level signal b1 corresponding to the dirt 12 is also generated at the output b of the diffusely reflected light receiver 7. Therefore, in the calculation output C obtained by taking the difference between the two in the analog calculation circuit 10 of FIG. 4, these signals a1. b
1 is canceled out and erased.
一方、金属板５の表面に第５図（Ａ）で示すような疵１
３が存在すると、その部分では正反射光が減少して乱反
射光が増大するため、正反射光用受光器６の出力ａには
疵１３に対応する低レベル信号ａ２が生じるのに対し、
乱反射光用受光器７の出ツノｂでは疵１３に対応して高
レベル信＠ｂ２が生じる。このため、これらの信号ａ
１ ｂ を互いに差引いて得られる演算出力Ｃにお
いては、強調された低レベル信号ｃ１が生じることにな
る。On the other hand, there are scratches 1 on the surface of the metal plate 5 as shown in FIG. 5(A).
3 exists, the specularly reflected light decreases and the diffusely reflected light increases in that part, so a low level signal a2 corresponding to the flaw 13 is generated at the output a of the specularly reflected light receiver 6.
At the output corner b of the diffusely reflected light receiver 7, a high level signal @b2 is generated corresponding to the flaw 13. Therefore, these signals a
In the calculation output C obtained by subtracting 1 b from each other, an emphasized low level signal c1 will result.
信号Ｃは第４図の微分処理回路１１で微分されて第５図
（Ｅ）に示す微分処理出力ｄとなるが、疵１３に対応す
る信号０１はこの微分出力ｄにおいて符号ｄ１で示す微
分波形となり、所定レベルのしきい値Ｃと比較されるこ
とにより、欠陥信号として検出される。以上の処理によ
り、汚れ１２を欠陥と誤認することなく本来の疵１３の
みが欠陥として検出される。The signal C is differentiated by the differential processing circuit 11 shown in FIG. 4 and becomes the differential processing output d shown in FIG. By comparing it with a threshold value C at a predetermined level, it is detected as a defect signal. Through the above processing, only the original flaw 13 is detected as a defect without misunderstanding the stain 12 as a defect.
ところで、一般の金属板の表面に存在づ゛る汚れは、上
記したように正反射光と乱反射光が同等に減少するもの
ばかりではなく、汚れの種類によって正反射光の減少の
割合の異なるものが多数ある。By the way, the dirt that exists on the surface of general metal plates does not necessarily reduce the specularly reflected light and the diffusely reflected light equally as described above, but also the dirt that reduces the specularly reflected light at different rates depending on the type of dirt. There are many.
したがって、上記従来例のように正反射光と乱反射光の
受光器出力を単純に引算処理するだ【ノでは、これらの
汚れに相当する出力は消去されず、欠陥とＦ Ｈされて
しまうことになる。例えば正反射光は減少するが乱反射
光は変化しない汚れの場合は欠陥として検出される。ま
た、欠陥とする必要のないチリや極微細な疵の場合には
正反射光があまり変化せず乱反射光のみが増大するとい
う反則特性を有するため、やはり欠陥として検出されて
しようことになる。さらに、上記従来例の場合は、第５
図（Ｅ）に示す微分処理出力ｄに光走査における端面信
号ｄ、ｄ３ （被検査体の端縁に相当する信号）の一部
も本来の欠陥信号ｄ１と同様に出力されてしまうので、
これを欠陥と誤認するおそれも有する。Therefore, if the receiver outputs of specularly reflected light and diffusely reflected light are simply subtracted as in the conventional example above, the outputs corresponding to these stains are not erased and are marked as defects. become. For example, if the specularly reflected light decreases but the diffusely reflected light does not change, the stain is detected as a defect. Furthermore, in the case of dust or very fine flaws that do not need to be treated as defects, they have a negative characteristic in that the specularly reflected light does not change much and only the diffusely reflected light increases, so they are likely to be detected as defects. Furthermore, in the case of the above conventional example, the fifth
Since a part of the end face signals d and d3 (signals corresponding to the edges of the object to be inspected) in optical scanning are also output to the differential processing output d shown in Figure (E) in the same way as the original defect signal d1,
There is also a risk that this may be mistaken for a defect.
（発明の目的）
この発明は従来技術における上述の問題の克服を意図し
ており、被検査体表面の欠陥を、それぞれ反射特性の異
なる種々の汚れや、チリや極微細な疵のように欠陥と見
做すに足らないものと明確に識５ＪＪ して検出するこ
とのできる表面欠陥検出装置を提供することを目的とす
る。(Purpose of the Invention) The present invention is intended to overcome the above-mentioned problems in the prior art, and is capable of detecting defects on the surface of an object to be inspected using various types of dirt, dust, and microscopic flaws, each having a different reflection characteristic. It is an object of the present invention to provide a surface defect detection device that can clearly identify and detect defects that are not worth considering.
（目的を達成するための手段）
上述の目的を達成するため、この発明の表面欠陥検出装
置では、被検査体表面が正常である場合を基準として、
正反射光と乱反射光とのぞれぞれの受光量に応じた信号
をそれぞれのしきい１１ａで弁別し、弁別侵の信号に対
して論理演算を行なうことにより、前記受光子のうらの
一方が増加しかつ他方が減少した際に検出出力を発生す
る受光信号増減検出手段を設け、この受光信号増減検出
手段の検出出力に基づいて表面欠陥を検出するにうに構
成されている。(Means for Achieving the Object) In order to achieve the above-mentioned object, the surface defect detection device of the present invention uses, as a reference, the case where the surface of the object to be inspected is normal.
By discriminating signals corresponding to the received amounts of specularly reflected light and diffusely reflected light using respective thresholds 11a, and performing logical operations on the signals that violate the discrimination, one of the back sides of the photoreceptor is detected. A light reception signal increase/decrease detection means is provided which generates a detection output when one increases and the other decreases, and a surface defect is detected based on the detection output of the light reception signal increase/decrease detection means.
（実施例）
第１図はこの発明の一実施例である表面欠陥検出装置の
概略図を示し、第２図はその装置における表面疵および
汚れに対する識別処理の出力波形を、第３図は黒い汚れ
および＃Ａ微細な疵に対する識別処理の出力波形をそれ
ぞれ示す。(Example) Fig. 1 shows a schematic diagram of a surface defect detection device which is an embodiment of the present invention, Fig. 2 shows the output waveform of the identification processing for surface flaws and dirt in the device, and Fig. 3 shows the black The output waveforms of the identification process for stains and #A minute flaws are shown, respectively.
第１図において、被検査体としての金属板１４の表面を
光走査する光走査手段１５は、レーザ光源１６．コリタ
ー９１フ１回転ミラー１８がらなり、レーザ光源１６よ
り取り出されたレーザビーム１９はコリメータ１７を経
て回転ミラー１８で反射され、その反射光により金属板
１４の表面を走査するように構成されている。光走査が
行われる上記金属板１４の片面側には、光照射によって
金属板１４の表面から反射する反射光のうちの正反射光
を受光する受光器２０と、上記反射光のうちの乱反射光
を受光する受光器２１とが配性されている。これら受光
３２０．２１はフォトマル。In FIG. 1, an optical scanning means 15 for optically scanning the surface of a metal plate 14 as an object to be inspected includes a laser light source 16. The laser beam 19 taken out from the laser light source 16 passes through the collimator 17 and is reflected by the rotating mirror 18, and the surface of the metal plate 14 is scanned by the reflected light. . On one side of the metal plate 14 where light scanning is performed, there is a light receiver 20 that receives specularly reflected light of the reflected light reflected from the surface of the metal plate 14 by light irradiation, and a light receiver 20 that receives the diffusely reflected light of the reflected light. A light receiver 21 is arranged to receive the light. These light receivers 320.21 are photomultiples.
フォトセルなとの光電変ＰＩ！Ｓ子がらなり、それぞれ
の受光量に応じた出力ｐ、ｓｈ＜得られる。上記正反射
光用受光器２ｏの次段にはアンプ２２を介して微分回路
２３および比較７！Ｊ２４が接続され、乱反射用受光７
９２１の次段にも同様にアンプ２５を介して微分回路２
６および比較器２７が接続されている。上記正反射光用
比較器２４には、微分回路２３の出力ｑ（そのＯレベル
は金属板１４の表面が正常面である場合の受光器２０の
出力レベルに対応している）のＯレベルより負の極性側
に所定レベルだけ漏らせた第１のしきい値（第２図（Ｂ
）、第３図（Ｂ）に符号ｆで示す）が設定されている。Photoelectric transformation PI with photocell! The outputs p and sh are obtained according to the amount of light received by each S element. The next stage of the specularly reflected light receiver 2o is a differentiating circuit 23 via an amplifier 22 and a comparison circuit 7! J24 is connected and light receiving 7 for diffuse reflection
Similarly, the differentiation circuit 2 is connected to the next stage of 921 via the amplifier 25.
6 and a comparator 27 are connected. The specularly reflected light comparator 24 is supplied with a signal from the O level of the output q of the differentiating circuit 23 (the O level corresponds to the output level of the light receiver 20 when the surface of the metal plate 14 is a normal surface). The first threshold value is leaked to the negative polarity side by a predetermined level (Fig.
), and (indicated by symbol f in FIG. 3(B)) are set.
一方、上記乱反射光用比較器２７には、微分回路２６の
出力ｔ（そのＱレベルは金属板１４の表面が正常面であ
る場合の受光器２１の出力レベルに対応している）の０
レベルより正の極性側に所定レベルだけ偏らせた第２の
しきい値（第２図（Ｅ）、第３図（Ｅ）に符号Ｑで示す
）が設定されている。そして、各比較器２４．２７より
得られる２値化出力ｒ、ｕは、その次段のＡＮＤ回路２
８に送られて、ここで論理積をとるように構成されてい
る。そして、これらによって受光信号増減検出手段３０
が構成されている。On the other hand, the comparator 27 for diffusely reflected light has an output t of the differential circuit 26 (its Q level corresponds to the output level of the light receiver 21 when the surface of the metal plate 14 is a normal surface).
A second threshold value (indicated by Q in FIGS. 2(E) and 3(E)) is set, which is biased toward the positive polarity side by a predetermined level. Then, the binary outputs r and u obtained from each comparator 24 and 27 are outputted to the AND circuit 2 at the next stage.
8 and is configured to perform a logical product here. By these, the light reception signal increase/decrease detection means 30
is configured.
つぎに、この装置の動作を、上記金属板１４の表面に表
面疵および通常の汚れのある場合と、黒い汚れおよび極
微細な疵のある場合とに分【プて以下に説明する。Next, the operation of this device will be explained below by dividing the operation into cases where the surface of the metal plate 14 has surface flaws and normal dirt, and cases where there is black dirt and extremely fine flaws.
■ 表面疵および通常の汚れのある場合レーザビーム１
９が照射される金属板１４の表面の光走査部分に表面疵
があると、その正反射光は減少する一方、乱反射光は増
大する。そのため、正反射光用受光器２０の出力ｐ（第
２図（Ａ））には上記表面疵に相当する低レベル信号ｐ
１が生じる。したがって、アンプ２２で増幅された上記
出力ｐを受ける微分回路２３からの微分処理出力ｑ（第
２図（Ｂ））には上記低レベル信号ｐ１に相当する微分
波形ｑ１が生じる。■ Laser beam 1 if there are surface scratches or normal dirt.
If there is a surface flaw in the light scanning portion of the surface of the metal plate 14 that is irradiated with the metal plate 9, the specularly reflected light will decrease, while the diffusely reflected light will increase. Therefore, the output p of the specularly reflected light receiver 20 (FIG. 2(A)) contains a low level signal p corresponding to the surface flaw.
1 occurs. Therefore, a differential waveform q1 corresponding to the low level signal p1 is generated in the differential processing output q (FIG. 2(B)) from the differential circuit 23 which receives the output p amplified by the amplifier 22.
この微分処理出力ｑは比較器２４において第１のしきい
値ｆと比較・弁別され、第２図（Ｃ）に示ず２値化出力
ｒとして、上記微分波形ｑ１に対応する＠ ｉｇｈ信号
ｒ１が出力される。This differential processing output q is compared and discriminated with a first threshold value f in a comparator 24, and is converted into a binary output r (not shown in FIG. 2C) as a @high signal r1 corresponding to the differential waveform q1. is output.
これに対して、増大する乱反射光を受ける乱反射光用受
光器２１の出力Ｓ（第２図（Ｄ））には、前記の表面疵
に相当する高レベル信号Ｓ１が生じる。そのため、アン
プ２５で増幅された上記出力Ｓを受ける微分回路２６か
らの微分処理出力ｔ（第２図（Ｅ））には、上記高レベ
ル信号ｓ１に相当する微分波形で１が生じる。この微分
処理出力ｔは比較器２７において第２のしきい値ｑと比
較・弁別され、第２図（Ｆ）に示す２値化信号Ｕとして
、上記微分波形ｔ１に対応するＨｉｇｈ信号ｕ信号比１
される。次段のＡＮＤ回路２８では、各比較器２４．２
７の出力ｒ、ｕの論理積をとるため、第２図（Ｇ）に示
すようにその出力■として表面疵に相当するＨ ｉａｈ
信号ｖ１が桿られる。On the other hand, a high level signal S1 corresponding to the above-mentioned surface flaw is generated in the output S (FIG. 2(D)) of the diffusely reflected light receiver 21 which receives the increasing diffusely reflected light. Therefore, the differential processing output t (FIG. 2(E)) from the differential circuit 26 which receives the output S amplified by the amplifier 25 has a differential waveform of 1 corresponding to the high level signal s1. This differential processing output t is compared and discriminated with a second threshold q in a comparator 27, and a high signal u signal ratio corresponding to the differential waveform t1 is generated as a binary signal U shown in FIG. 2(F). 1
be done. In the next-stage AND circuit 28, each comparator 24.2
In order to calculate the logical product of the outputs r and u of 7, as shown in Fig. 2 (G), the output ■ is H iah corresponding to the surface flaw.
A signal v1 is transmitted.
一方、金属板１４の表面の光走査部分に通常の汚れがあ
ると、その正反射光が減少するのに対し、乱反射光はほ
とんど変化しない。そのため、正反射光用受光器２０の
出力ｐには、上記汚れに相当する低レベル信＠ｐ２が生
じる。したがって、正反射光用微分回路２３の微分処理
出力ｑには、上記低レベル信号ｐ２に相当する微分波形
ｑ２が生しる。この微分処理出力ｑは比較器２４で第１
のしきい値ｆと比較・弁別され、比較；Ｓ２４の２値化
出力ｒとして第２図（Ｃ）に示すように上記微分波形ｑ
に対応するト１ｉｇｈ信号ｒ２が出力される。On the other hand, if there is normal dirt on the optical scanning portion of the surface of the metal plate 14, the specularly reflected light decreases, whereas the diffusely reflected light hardly changes. Therefore, a low level signal @p2 corresponding to the above dirt is generated in the output p of the specularly reflected light receiver 20. Therefore, the differential processing output q of the specularly reflected light differential circuit 23 produces a differential waveform q2 corresponding to the low level signal p2. This differential processing output q is outputted by the comparator 24 to the first
The differential waveform q is compared and discriminated with the threshold value f of the differential waveform q as shown in FIG.
A high signal r2 corresponding to the output signal r2 is output.
これに対して、増減変化のない乱反射光を受ける受光器
２１の出力Ｓには、上記汚れに相当する信号変化は生じ
ない。したがって乱反射光用微分回路２６の微分処理出
力ｑにも、上記汚れに相当する微分波形は生じず、比較
器２７の２値化出力Ｕとして汚れに相当するＨｉｇｈ信
号は生じない。On the other hand, in the output S of the light receiver 21, which receives the diffusely reflected light that does not increase or decrease, no signal change corresponding to the above dirt occurs. Therefore, a differential waveform corresponding to the dirt is not generated in the differential processing output q of the differential circuit 26 for diffusely reflected light, and a High signal corresponding to the dirt is not generated as the binarized output U of the comparator 27.
このため、ＡＮＤ回路２８には一方の比較器２４からの
ｌ−１ｉｇｈ信号のみが入力され、このＡＮＤ回路２８
の出力■はｌｏｗ信号となる。すなわち、上記汚れは欠
陥として検出されることはない。Therefore, only the l-1high signal from one of the comparators 24 is input to the AND circuit 28, and this AND circuit 28
The output ■ becomes a low signal. That is, the above dirt is not detected as a defect.
また、各受光器２０．２１の出力ｐ、ｓは光走査の一走
査区間の始端と終端において急峻な立上りと立下がりを
呈するので、微分処理出力ｑ、ｔにこれらに相当する端
面波形ｑ 、Ｑ 、ｉ３゜ｔ４が生じるが、正反射光
用比較器２４では終端側の端面波形ｑ４のみが第１のし
きい値ｆとクロスするのみであり、使方乱反射光用比較
器２７では始端側の端面波形ｔ３のみが第２のしきい値
ｑとクロスするのみであるから、２つの比較器２４゜２
７から端面信号に相当づるＨｉｇｈ信号ｒ３．Ｌｊ３が
同時に得られることはなく、光走査の始端。In addition, since the outputs p and s of each optical receiver 20 and 21 exhibit steep rises and falls at the beginning and end of one scanning section of optical scanning, the differential processing outputs q and t have end face waveforms q, corresponding to these, Q, i3°t4 occurs, but in the comparator 24 for regular reflection light, only the end face waveform q4 on the terminal side crosses the first threshold f, and in the comparator 27 for diffuse reflection light, the waveform q4 on the end face crosses the first threshold f. Since only the end face waveform t3 crosses the second threshold q, the two comparators 24°2
7 to High signal r3 corresponding to the end face signal. Lj3 is never obtained at the same time and is the starting point of optical scanning.
終端に相当する信号が欠陥と誤認されることはない。The signal corresponding to the termination will not be mistaken as a defect.
■ 黒い汚れおよび極微細な疵のある場合金属板１４の
光走査部分に黒い汚れがあると、その反射光および乱反
射光はいずれも減少する。(2) In the case of black dirt and very fine flaws If there is black dirt on the optical scanning part of the metal plate 14, both the reflected light and diffusely reflected light are reduced.
そのため受光器２０．２１の各出力ｐ、Ｓには、第３図
（△）、第３図（Ｄ）に示すように上記黒い汚れに相当
する低レベル信号ｐ２′、６２′が生じ、これらの信号
ｐ２′、 ２′はそれぞれ微分回路２３．２６を経て、
第３図（Ｂ）、第３図（Ｅ）に示すようにほぼ同じ微分
波形ｑ ’、ｔ２′となる。Therefore, low-level signals p2' and 62' corresponding to the above-mentioned black stains are generated at the outputs p and S of the photoreceiver 20.21, as shown in Fig. 3 (△) and Fig. 3 (D). The signals p2' and 2' pass through differentiating circuits 23 and 26, respectively, and
As shown in FIG. 3(B) and FIG. 3(E), substantially the same differential waveforms q' and t2' are obtained.
ところで、正反射光用比較器２４では微分処理出力ｑを
負の極性のしきい値「で比較・弁別するため、第３図（
Ｂ）に示すように微分波形（１２’の降下部（前半部）
がしきい値ｆとクロスするのに対して、乱反射光用比較
器２７では微分処理出力ｔを正の極性のしきい値ｑと比
較・弁別するため・第３図（Ｅ）に示すように微分波形
ｔ’の上昇部（後半部）がしきい値Ｑとクロスする。し
たがって各比較器２４．２７から出力される上記黒い汚
れに相当するＨｉａｈ信号ｒ ’、ＬＪ２’ は時間
軸上の同一位置に生じることはなく、ＡＮＤ回路２８か
らは上記黒い汚れに相当するＨ ｉｇｈ信号は得られな
い。すなわち、黒い汚れが欠陥として検出されることは
ない。By the way, in the specularly reflected light comparator 24, the differential processing output q is compared and discriminated using a threshold value of negative polarity.
As shown in B), the differential waveform (12' descending part (first half)
crosses the threshold value f, whereas the diffuse reflection light comparator 27 compares and discriminates the differential processing output t with the positive polarity threshold value q. As shown in FIG. 3(E), The rising part (second half) of the differential waveform t' crosses the threshold value Q. Therefore, the Hiah signals r' and LJ2' corresponding to the black stains outputted from each comparator 24 and 27 do not occur at the same position on the time axis, and the High signals corresponding to the black stains from the AND circuit 28 are not generated at the same position on the time axis. I can't get a signal. That is, black stains are not detected as defects.
一方、金属板１４表面の光走査部に極微細な疵（チリの
場合も同様）があると、その正反射光は変化せず乱反射
光のみが増大する。そのため乱反射光用受光器２１の出
力Ｓにのみ、上記疵に相当する高レベル信号Ｓ ′が生
じ、微分回路２６の微分処理出力ｔにのみ上記高レベル
信号Ｓ ′に対応する微分波形ｔ ′が生じる。この微
分波形ｔ１′は比較器２７により第２のしきい値ｑで比
較・弁別されＨｉｇｈ信Ｑｕ ’ として出力される
。On the other hand, if there is a very fine flaw (the same applies to dust) on the optical scanning part on the surface of the metal plate 14, the specularly reflected light does not change and only the diffusely reflected light increases. Therefore, only in the output S of the diffusely reflected light receiver 21 is a high level signal S' corresponding to the above flaw, and only in the differential processing output t of the differentiating circuit 26 is a differential waveform t' corresponding to the high level signal S'. arise. This differential waveform t1' is compared and discriminated by a second threshold q by a comparator 27 and outputted as a high signal Qu'.
これに対し正反射光用比較器２４がらは上記疵に相当す
る＠ ｉｇｈ信号は出力されないので、ＡＮＤ回路２８
からは上記極微細な疵に対応するｌ−１ｉａｈ信号は出
力されない。したがって、極微細な疵が欠陥として検出
されることはない。すなわち、先）ホした通常の表面疵
とは明確に区別される。On the other hand, since the specular reflection light comparator 24 does not output the @high signal corresponding to the above flaw, the AND circuit 28
The 1-1iah signal corresponding to the extremely minute flaw is not output from the . Therefore, extremely minute flaws are not detected as defects. In other words, it is clearly distinguished from the normal surface flaws mentioned above.
以上の実施例では、正反射光が増大し、乱反射光が減少
する反射特性を呈する通常の表面疵を、欠陥と見做ずに
足りない他の汚れや極微細な疵などと識別して検出する
場合を例示したが、表面欠陥には正反射光が増大し乱反
射光が減少するような反射特性の光沢性欠陥もあるので
、このような欠陥を検出しようとする場合には、先の実
施例において、しきい値ｆ、Ｑの正負の極性を、比較器
２４．２７の間で逆にすれば同様にして検出することが
できる。In the above example, a normal surface flaw exhibiting reflection characteristics in which specularly reflected light increases and diffusely reflected light decreases is detected by distinguishing it from other dirt or extremely minute flaws that are not considered defects. However, surface defects include glossy defects with reflection characteristics that increase specularly reflected light and decrease diffusely reflected light. In the example, if the positive and negative polarities of the thresholds f and Q are reversed between the comparators 24 and 27, detection can be performed in the same way.
また、受光Ｚ２４．２７の出力から汚れや疵に相当する
信号成分をピックアップするだめの処理として、上記実
施例では微分処理を行うようにしているが、これに限ら
ず池の手段を用いて汚れ、疵の信号成分を強調するよう
にしてもよい。さらに、２つの受光器２２．２５の出力
のうちの一方のみを反転させた後にそれぞれを微分した
場合には、上記第１と第２のしきい値として同一極性の
値を用いることによって上記と同様の結果を得ることが
できるため、第１と第２のしきい値が互いに異する極性
であることは必須ではない。比較器２４．２７として、
入力信号がしきい値より小さいときに＠ ｉｇｈ信号を
出力するタイプを使用した場合には、ＡＮＤ回路２８の
かわりにＮＯＲ回路を用いればよい。Further, as a process for picking up signal components corresponding to dirt and scratches from the output of the light receiving Z24.27, differential processing is performed in the above embodiment, but the present invention is not limited to this. , the signal component of the flaw may be emphasized. Furthermore, if only one of the outputs of the two light receivers 22, 25 is inverted and then differentiated, the above can be achieved by using values of the same polarity as the first and second thresholds. It is not essential that the first and second thresholds have different polarities since similar results can be obtained. As comparator 24.27,
If a type that outputs the @high signal when the input signal is smaller than the threshold value is used, a NOR circuit may be used instead of the AND circuit 28.
このように、この発明は種々の弁別や論理演算によって
達成可能である。In this way, the present invention can be achieved through various discriminations and logical operations.
（発明の効果）
以上のように、この発明の表面欠陥検出装置によれば、
被検査体表面の欠陥を、反射特性のそれぞれ異なる各種
の汚れや欠陥と見做ずに足らない極微細な疵および光走
査区間の始端・終端に生じる端面信号とも明確に識別し
て検出することができ、表面検査精度が大幅に向上する
という効果が得られる。(Effects of the Invention) As described above, according to the surface defect detection device of the present invention,
To clearly distinguish and detect defects on the surface of an object to be inspected from microscopic flaws that are too small to be considered as various types of dirt and defects with different reflection characteristics, and end face signals that occur at the start and end of an optical scanning section. This has the effect of significantly improving surface inspection accuracy.
第１図はこの発明の一実施例である表面欠陥検出装置の
概略図、
第２図は実施例における表面疵および通常の汚れの識別
処理の出力波形図、
第３図は実施例における黒い汚れおよび極微細な疵の識
別処理の出力波形図、
第４図は従来の表面欠陥検出装置の概略図、第５図は従
来装置の信号処理の出力波形図である。
１５・・・光走査手段、２０・・・正反射光用受光器、
２１・・・乱反射光用受光器、
２４・・・正反射光用受光器、Fig. 1 is a schematic diagram of a surface defect detection device which is an embodiment of the present invention, Fig. 2 is an output waveform diagram of surface flaws and normal dirt identification processing in the embodiment, and Fig. 3 is a black stain in the embodiment. FIG. 4 is a schematic diagram of a conventional surface defect detection device, and FIG. 5 is an output waveform diagram of signal processing of the conventional device. 15... Optical scanning means, 20... Specular reflection light receiver,
21... Light receiver for diffusely reflected light, 24... Light receiver for regular reflected light,
Claims (1)
体からの正反射光と乱反射光とを受光手段でそれぞれ受
光し、前記受光手段におけるそれぞれの受光量に基づい
て前記被検査体表面に存在する表面欠陥を検出する表面
欠陥検出装置において、 前記被検査体表面が正常面である場合を基準として、前
記正反射光と前記乱反射光とのそれぞれについての受光
量に応じた信号をそれぞれのしきい値で弁別し、弁別後
の信号に対して論理演算を行なうことにより、前記受光
量のうちの一方が増加しかつ他方が減少した際に検出出
力を発生する受光信号増減検出手段を設け、 前記受光信号増減検出手段の検出出力に基づいて前記表
面欠陥を検出することを特徴とする表面欠陥検出装置。(1) The object to be inspected is irradiated with light from a light source, the specularly reflected light and the diffusely reflected light from the object to be inspected are each received by a light receiving means, and based on the amount of light received by the light receiving means, the object is to be inspected. In a surface defect detection device that detects a surface defect existing on the surface of an object to be inspected, the amount of light received for each of the specularly reflected light and the diffusely reflected light is determined based on the case where the surface of the object to be inspected is a normal surface. By discriminating the signals using respective threshold values and performing logical operations on the signals after discrimination, a detection output is generated when one of the received light amounts increases and the other decreases. A surface defect detection apparatus, comprising: a detection means, and detects the surface defect based on a detection output of the light reception signal increase/decrease detection means.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61067898A JPH0610658B2 (en) | 1986-03-25 | 1986-03-25 | Surface defect detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61067898A JPH0610658B2 (en) | 1986-03-25 | 1986-03-25 | Surface defect detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62223654A true JPS62223654A (en) | 1987-10-01 |
| JPH0610658B2 JPH0610658B2 (en) | 1994-02-09 |
Family
ID=13358174
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61067898A Expired - Lifetime JPH0610658B2 (en) | 1986-03-25 | 1986-03-25 | Surface defect detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0610658B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05322794A (en) * | 1992-02-28 | 1993-12-07 | Sumitomo Metal Ind Ltd | Defect inspecting device |
| JP2006317274A (en) * | 2005-05-12 | 2006-11-24 | Jfe Steel Kk | Surface inspection method of stainless steel sheet and surface inspection device for stainless steel sheet |
| CN112485272A (en) * | 2020-12-14 | 2021-03-12 | 紫创(南京)科技有限公司 | Semiconductor detection device and detection method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5998748U (en) * | 1982-12-24 | 1984-07-04 | ヤンマー農機株式会社 | threshing equipment |
| JPS60171143U (en) * | 1984-04-19 | 1985-11-13 | セイレイ工業株式会社 | Crimp net device in threshing section |
-
1986
- 1986-03-25 JP JP61067898A patent/JPH0610658B2/en not_active Expired - Lifetime
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5998748U (en) * | 1982-12-24 | 1984-07-04 | ヤンマー農機株式会社 | threshing equipment |
| JPS60171143U (en) * | 1984-04-19 | 1985-11-13 | セイレイ工業株式会社 | Crimp net device in threshing section |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05322794A (en) * | 1992-02-28 | 1993-12-07 | Sumitomo Metal Ind Ltd | Defect inspecting device |
| JP2006317274A (en) * | 2005-05-12 | 2006-11-24 | Jfe Steel Kk | Surface inspection method of stainless steel sheet and surface inspection device for stainless steel sheet |
| CN112485272A (en) * | 2020-12-14 | 2021-03-12 | 紫创(南京)科技有限公司 | Semiconductor detection device and detection method |
| CN112485272B (en) * | 2020-12-14 | 2021-11-09 | 紫创(南京)科技有限公司 | Semiconductor detection device and detection method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0610658B2 (en) | 1994-02-09 |
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