JPH022098B2

JPH022098B2 -

Info

Publication number: JPH022098B2
Application number: JP12001079A
Authority: JP
Inventors: Hiroshi Aoki; Naomasa Takusagawa
Original assignee: Teijin Ltd
Current assignee: Teijin Ltd
Priority date: 1979-09-20
Filing date: 1979-09-20
Publication date: 1990-01-16
Also published as: JPS5644830A

Description

【発明の詳細な説明】[Detailed description of the invention]

この発明は、光透過性を有するプラスチツクな
どのフオイル、フイルム、ウエブまたはシートの
ようなシート状物を走行させながら、このシート
状物に投光器から光スポツトを照射して、その透
過光及び（又は）散乱光を受光器により受光し、
シート状物に存在する各種の欠点を検出しかつ識
別するシート状物の欠点検出装置の改良に係るも
のである。シート状物の表面欠陥を光学的飛点走査方式に
より検出する技術は、例えば特開昭52−29789号
公報に開示されている。この従来技術は光源とし
て単色光のレーザを使用し、光路に穴あき鏡を介
在させることによつて、シート状物の表面に欠点
が存在するとき、その散乱光による光量の変化を
受光器、光電変換器によつて電気的に演算しなが
ら検出するものである。シート状物、とくにプラスチツクフイルムなど
の表面欠陥としては、種々なものが在るが、シー
ト状物表面への油、塵埃などの附着とシート状物
自体の欠点とに大別される。殊にシート状物の表
面に凹凸をもつ傷が存在すると、その部分に光ス
ポツトが投じられると散乱が起り、この散乱の程
度からシート状物表面の傷の位置、大きさが検知
できる。また前者の表面附着異物の場合には透過
光量が減少することから、その附着物の存在が検
出できる。先行技術では、シート状物表面の附着物（下記
(1)の欠陥）と表面傷（下記(2)〜(4)の欠点）とを識
別するために、穴あき遮蔽板と夫々の欠陥識別手
段を設けている。しかるに、昨今、シート状物の
用途によつてはシート状物の表面傷を更にその欠
点の性質により詳細に識別する必要が生じてい
る。シート状物の欠点は、(1)表面附着物、(2)シー
ト状物表面に微小な点状の欠点として偶発的に生
ずるもの、(3)シート状物の表面に筋（線）状に現
われる傷、(4)シート状物の表面に広範囲に生ずる
微細な凹凸でオレンジの皮様な欠陥、などが現わ
れるものである。そして、上記(2)と上記(4)との欠
点は電気的に識別が容易である。ここに、(1)の表
面附着物はロール等に附着していた油や汚れが転
写される場合が多く、しばしば周期的に現われ
る。同様に(3)の筋状の欠陥もロールの傷の転写の
場合やダイによつて形成される場合があり周期的
または連続的であつて発生頻度は極めて低い。更
に、(4)の欠点はキヤステイングドラムへのシート
状物の密着異常やキヤステイングドラム表面の汚
れなどに原因している。それ故、(2)のシート状物
にランダムに現われる欠点の検出が最も重要であ
るとともに、この欠点を更に詳しく識別する必要
がある。シート状物に現われる点状の欠点は、（２−ａ）
プラスチツクシートの溶融押出に際し偶発的に混
入される気体によつて生ずる気泡、（２−ｂ）小
さな表面傷であつて所謂フイツシユアイ、（２−
ｃ）プラスチツクシートに混入される熱分解物、
その他の異物などである。本発明の装置はこのシート状物の表面の小欠点
である上記の３種（2a〜2c）の欠陥を識別する
新規な技術を提供することを目的とするものであ
る。本発明は、透光性を有するシート状物を走行さ
せながら該シート状物に飛点走査方式によつて光
スポツトを照射する投光手段、該シート状物を透
過した透過光及び散乱光を部分的に遮蔽する遮蔽
手段、散乱光を受光する受光手段、光電変換手
段、シート状物の表面欠点を演算、表示、記録す
る検知手段とからなるシート状物の欠点検出装置
において、前記投光手段の光スポツト径を調整す
る光量調整手段、前記遮蔽手段に設けられた遮蔽
光量調整手段、およびシート状物の走行位置と前
記受光手段との距離を変化調整できる手段からな
る改良手段の少くとも１手段を設け、シート状物
表面の微小欠点を識別し得るように光学的改良を
施してなるシート状物の欠点検出装置である。本発明を説明する。シート状物の表面に、偶発
的に生ずる微細な欠点は、電気的な演算回路によ
つて識別することは実際上できない。これらの識
別はこれらの欠点に固有な散乱光の散乱状態を利
用して、光学的な手段によつて判別できる。この
理由は、シート状物表面の欠点が比較的限定され
た小さなものであるが、光スポツトに対する散乱
の状態が欠点によつて拡がり易い気泡によるも
の、散乱が殆ど起らないシートに含有された異
物、この中間の散乱性を呈するフイツシユアイ
を、散乱状態に着眼して選択的に観測することが
できるからである。本発明に使用する欠点検出装置は、従来公知の
装置を改良して利用でき、光学系を改造すること
によつてシート状物の微小欠点を詳細に分離識別
できるものである。即ち、本発明に供するシート状物の欠点検査装
置は、シート状物を走行させるためのロール群と
このロールの駆動及び駆動制御装置を含む補助手
段、シート状物の表面欠点を検知するための主要
手段とからなる。そして、主要手段は、光スポツ
トをシート状物の走行方向対し垂直に（即ちシー
ト状物の幅方向）走査する走査機構を含む投光手
段、シート状物を透過した光を光電増倍管等で受
光する受光手段、透過光を受光する受光面に設け
た光量調整のための遮蔽手段、受光手段と連続し
た電気回路からなる検知手段であつて、シート状
物表面欠点を表示記録できる機構を備えたものか
ら構成される。本発明の投光手段は、光源として単色光のビー
ムが好ましく、例えば公知のヘリウム−ネオン系
ガスレーザ、アルゴンレーザなどが使用できる。
出力としては特に限定はないが、光学的な検査目
的での使用であるから１〜100ｍＷ程度で充分で
ある。レーザ光は、レンズを介在させて、そのビ
ーム径を0.2〜３mm直径程度に集光させる。集光
したビームを回転多面鏡または振動鏡によつて走
行中のシート状物の表面に適度な光スポツトが走
査されるように光学系路を設定する。この際、走
査巾（検査巾）が著しく大きいと端部と中央部と
では走査速度が変つてくるから、光学系を複数設
けて検査巾を狭くし、広幅のシート状物の検査を
完全になし得る。本発明では、レーザ光がシート状物の表面に達
したときの光スポツトの径が調整できるように改
良している。即ち、集光レンズの組合せを変えた
ものとプリズム及び（又は）反射鏡との複数の光
路を備えた投光手段に改良の第１点が在る。光ス
ポツト径を大きくすると、シート状物の微細な表
面欠点は検出され難くなる。例えば、光スポツト
径が0.2〜1.0mm程度では、シート状物の欠点のう
ち気泡の検出感度が最も高い。これに対して、光
スポツト径を1.3mm以上に調整すると、大きな表
面欠点となる確率の低低い気泡欠点は殆ど検出さ
れず、比較的大きな表面欠点を有する分解異物が
検知される。従つて、投光手段として、スポツト
径を0.2〜0.8mm程度とした観測系とスポツト径1.3
mm〜２mm程度の観測系とを備えることによつて、
シート状物の点状欠点の総数、分解異物の数、等
が測定でき、更に1.0〜1.3mm程度のスポツト径を
併用すると、これらの欠点の全貎を簡単な演算か
ら知ることができる。また、検出感度全体を高める必要があるときに
は、波長の短い光源を使用する方が有利であり、
出力を高くするとともに、スポツト径を細くする
ことが好ましいことは上記に説明した通りであ
る。本発明の装置における受光手段は光スポツトの
走査線の下方に受光面を設け、シート状物に何ら
の欠点もなく光が単に透過する場合には、受光素
子となる光電子増倍管に光が当らないように遮蔽
板を受光面に設けておく。そして、シート状物に
欠点が存在すると透過光は散乱され、その散乱光
のみを受光素子が受光するようにした散光板直受
方式が好ましい。これは、プラスチツクフイルム
の如きシート状物では透明性が高いこと、散乱光
の受光度を高くする必要があることを理由とする
ものである。本発明の改良装置では、遮蔽板の配置を調整で
きるものであつて、遮蔽面積を大きくすることに
よつて受光素子に達する散乱光の光量を減少せし
め、検出感度を低くすることができる。この際散
乱し易い欠点である気泡やフイツシユアイは、遮
蔽面積を増加させると著しい光量減少があるか
ら、遮蔽量を調整することによつて光量減少の低
い分解異物による欠点と気泡・フイツシユアイと
を識別できる。遮蔽板はスポツト径よりも１〜２
mm広い巾とし、３〜５mm巾程度の不透光性の材料
である例えば黒色のテープを用いて受光面を覆
う。そして、特に気泡やフイツシユアイを観測す
るには、光スポツトの走査線上に黒色テープを貼
ればよい。また、分解異物を主に観測するにはこ
の黒色テープに平行に別の黒色テープを更に２
本、主たる前記黒色テープを中心に貼るとよい。
この際黒色テープと別のテープとの間隔を適宜調
整すると、受光量の変化からシート状物の表面欠
点を分離識別できる。例えば、主テープと別の副
テープとの受光可能な間隔を約１mmとし主テープ
巾を約５mmとすれば、分解異物の検出感度は気泡
やフイツシユアイの検出感度よりも高くなる。従
つて、本発明では遮蔽面積を調整できるような機
構を受光面に備えることによつて観測目的とする
表面欠点を選択できる。具体的には中央に固定遮
蔽板を置き、側方に設けた１組の遮蔽板を受光面
の間隔が変化するように摺動できる機構をもつ遮
蔽光量調整手段が例示できる。勿論、１組の遮蔽
板は摺動する代りに受光面を傾斜するように回転
させ、有効遮蔽量（投影量）を調整することもで
きる。別な簡便な方式として予め種々の遮蔽量を
もつ遮蔽手段を準備し、必要なものを受光面に取
りはずし自在に取付ければよい。投光手段から投じられた光がシート状物と投光
手段との間に焦点をもつように光学系を調整する
と、シート状物を透過した光は拡大し、スポツト
径に比較して受光面での光の巾は拡げられる（ス
ポツト径は走査した光線の巾として観測される）。
そこで、この拡大率は、焦点とシート状物との距
離に対する焦点と受光手段（受光面）との距離と
なる。焦点位置をシート状物に接近させるかまた
は受光手段の位置をシート状物から遠ざけること
によつて、拡大率を増加させることができ、また
相対距離の変化を逆にすれば、拡大率を減少でき
る。拡大率が大きくなると表面欠点による散乱光
の光量密度は減少し、検出感度と散乱効果から分
解異物の検出が容易となる。分解異物を主に検出
するには拡大率を２倍〜10倍、殊に３倍〜８倍と
するとよい。拡大率を大きくすると散乱性の低い
分解異物と散乱し易い気泡・フイツシユアイとの
識別が困難となる。本発明を図面により説明する。第１図は本発明装置の概要を示す斜視図であ
る。投光手段１０と受光手段２０との間に、シー
ト状物（図示せず）を公知の走行手段（図示せ
ず）により走行させる。走行手段は、一方でロー
ル状に捲かれたシート状物を解舒し他方で捲取り
ながら表面欠点を検査するような一群のロールが
使用できる。勿論シート状物を製造する工程にこ
の投光手段と受光手段、及び光電変換手段と検知
手段とを設けることができ、製造手段をシート状
物の走行手段となし得る。投光手段は、アルゴンまたはヘリウム−ネオン
などのレーザー光源、発生器、プリズム、レンズ
等を含む投光器１２と投光器より出たレーザー光
を受光面に到達させる振動ミラー１６からなる。
この振動ミラーは数ｋHz程までの振動を加えるこ
とによつて、高速度の走査が可能となる。振動ミ
ラーに替えて、多面鏡を高速回転させることによ
つて同等のレーザー光の走査が可能である。第１
図では投光器及び振動ミラーをシート状物の巾方
向１列に２器並べ、走査幅をシート巾の1/2とし
た例である。また２組（４個）の光学系は、レン
ズ系を異にしシート状物表面におけるスポツト径
（走査光線の幅）を２様とし、検出回路によるシ
ート状物表面欠点の識別を可能としたものであ
る。スポツト径を変化させ、表面欠点の検出感度
を調整するためには、レンズ系を異にする投光器
を取換えることができる。このようにして光量調
整が可能となる。レーザー光は振動ミラーを径て走行するシート
状物を透過し受光手段２０に達する。受光手段は
走査光の位置に対応した広幅のスリツト２２とス
リツトを径た光を受光する光電子増幅管２８との
間に透過光の遮蔽手段が第２図の如く設けられて
いる。透過光が表面欠点のないシート状物を経た
場合には、光電子増倍管に直接光が当らないよう
に固定遮蔽板２４により透過光は遮蔽される。ま
た透過光がシート状物の表面欠点を透過して散乱
された場合には光量調整用の回転遮蔽板２６と固
定遮蔽板２４との間隙を通過する透過光が光電子
増倍管に達する。この際回転遮蔽板は透過光の方
向に対し傾斜しているから、回転角度（傾斜角
度）を調整することにより光量が調整される。な
お、透過光量の調整手段としては、第２図の回転
遮蔽板に替えて、摺動可能な遮蔽板を設け固定遮
蔽板との間隙が変化するようになし得る。摺動に
はラツク歯車を含む公知の手段が使用できる。受光手段を昇降手段４０に載せ、シート状物と
受光面との距離を変化させることができる。レー
ザー光の焦点がシート状物と投光器の間に在る
と、昇降手段により透過光の拡大率を変化させる
ことができる。この際投光器のレンズを交換する
方式を併用すると、拡大率は一層広範囲に変え得
る。第３図は第１図の装置を光学系に限つて平面的
に展開したものである。レーザー光源１１より発
生した光がレンズ１３及び１４を径て振動ミラー
１６により飛点走査される。そして、要すれば平
面鏡Ｍ及びM′を径てシート状物Ｓを透過した光
は受光手段のスリツト２２を通過したのち遮蔽板
２４及び２６の間隙を通過できた光量がフオトマ
ル２８に検出される。以下実施例により本発明を更に説明する。実施例１第３図に示した光学系に於て、レンズを交換し
てレーザー（He−Ne）光のビーム径を変化さ
せ、厚さ70μｍのポリエチレンテレフタレート２
軸延伸フイルムの表面の欠点の識別の可能性を検
討した。受光感度は、透過光を電気信号に変換し
たとき、無欠点シート状物を透過した光によるノ
イズに対し、種々の欠点をもつ散乱光 In this invention, a light spot is irradiated from a projector onto a sheet-like object such as a foil, film, web, or sheet made of light-transmitting plastic, while the sheet-like object is running, and the transmitted light and/or ) The scattered light is received by a light receiver,
The present invention relates to an improvement of a defect detection device for a sheet-like object that detects and identifies various defects present in a sheet-like object. A technique for detecting surface defects on a sheet-like material using an optical flying spot scanning method is disclosed in, for example, Japanese Patent Laid-Open No. 52-29789. This conventional technology uses a monochromatic laser as a light source, and by interposing a perforated mirror in the optical path, when a defect exists on the surface of a sheet-like object, changes in the amount of light due to the scattered light can be detected by a light receiver, It is detected while being electrically calculated using a photoelectric converter. There are various types of surface defects on sheet-like materials, especially plastic films, and they can be broadly classified into adhesion of oil, dust, etc. to the surface of sheet-like materials, and defects on the sheet-like material itself. In particular, when there are scratches with irregularities on the surface of a sheet-like object, scattering occurs when a light spot is projected onto that part, and the position and size of the scratch on the surface of the sheet-like object can be detected from the degree of scattering. In the case of the former foreign matter adhering to the surface, the amount of transmitted light decreases, so the presence of the adhering material can be detected. In the prior art, attachments on the surface of a sheet-like object (see below)
In order to distinguish between defects (1) and surface scratches (defects (2) to (4) below), a perforated shielding plate and defect identification means are provided. However, in recent years, depending on the use of the sheet-like material, it has become necessary to identify surface flaws on the sheet-like material in more detail based on the nature of the defect. Defects of sheet-like materials include: (1) surface adhesion, (2) minute defects that occur accidentally on the surface of the sheet-like material, and (3) streaks (lines) on the surface of the sheet-like material. (4) Fine irregularities that appear over a wide area on the surface of the sheet-like object, resembling an orange peel. The disadvantages of (2) and (4) above are easily distinguishable electrically. Here, the surface adhesion (1) is often a transfer of oil or dirt adhering to the roll, etc., and often appears periodically. Similarly, the streak-like defects (3) may be formed by transfer of scratches on the roll or by the die, and may be periodic or continuous, and the frequency of occurrence is extremely low. Furthermore, the drawback of (4) is caused by abnormal adhesion of the sheet material to the casting drum and dirt on the surface of the casting drum. Therefore, it is most important to detect defects that randomly appear in the sheet-like material (2), and it is necessary to identify these defects in more detail. The dot-like defects that appear on sheet-like materials are (2-a)
(2-b) Small surface scratches, so-called fissures, (2-b) bubbles caused by gas accidentally mixed in during melt extrusion of plastic sheets;
c) pyrolysis products mixed into plastic sheets;
Other foreign objects. The object of the apparatus of the present invention is to provide a new technique for identifying the above-mentioned three types (2a to 2c) of minor defects on the surface of the sheet-like material. The present invention provides a light projecting means for irradiating a light spot onto a sheet-like object by a flying spot scanning method while running the sheet-like object having a translucent property, and a light projecting means for irradiating a light spot onto the sheet-like object by a flying point scanning method, and a light projecting means for irradiating a light spot onto the sheet-like object while the sheet-like object has a translucent property. In the defect detection device for a sheet-like object, the apparatus includes a shielding means for partially shielding, a light-receiving means for receiving scattered light, a photoelectric conversion means, and a detection means for calculating, displaying, and recording surface defects of the sheet-like object. At least an improved means comprising a light amount adjusting means for adjusting a light spot diameter of the means, a shielding light amount adjusting means provided on the shielding means, and a means for changing and adjusting the distance between the traveling position of the sheet-like object and the light receiving means. This is a defect detection device for a sheet-like object, which is provided with one means and optically improved so as to be able to identify minute defects on the surface of the sheet-like object. The present invention will be explained. It is practically impossible to identify minute defects that occur accidentally on the surface of a sheet-like material using an electrical arithmetic circuit. These defects can be identified by optical means using the scattering state of scattered light specific to these defects. The reason for this is that the defects on the surface of the sheet-like material are relatively limited and small, but the scattering state for the light spot is due to air bubbles that easily spread due to the defects; This is because it is possible to selectively observe a foreign object, or a fisheye exhibiting scattering properties in between, by focusing on the scattering state. The defect detection device used in the present invention can be used by improving a conventionally known device, and by modifying the optical system, it can separate and identify minute defects in a sheet-like object in detail. That is, the sheet-like object defect inspection device according to the present invention includes a group of rolls for running the sheet-like object, an auxiliary means including a drive and drive control device for the rolls, and a device for detecting surface defects of the sheet-like object. It consists of the main means. The main means are a light projection means including a scanning mechanism that scans the light spot perpendicularly to the traveling direction of the sheet-like object (that is, in the width direction of the sheet-like object), and a photomultiplier tube or the like that transmits the light transmitted through the sheet-like object. A detection means consisting of a light receiving means for receiving light, a shielding means for adjusting the light amount provided on a light receiving surface for receiving transmitted light, and an electric circuit connected to the light receiving means, and a mechanism capable of displaying and recording defects on the surface of a sheet-like object. It is made up of the things it has. In the light projection means of the present invention, a monochromatic light beam is preferably used as a light source, and for example, a known helium-neon gas laser, argon laser, etc. can be used.
There is no particular limitation on the output, but since it is used for optical inspection purposes, about 1 to 100 mW is sufficient. A lens is used to condense the laser beam to a beam diameter of about 0.2 to 3 mm. The optical system path is set so that the focused beam is scanned by a rotating polygon mirror or a vibrating mirror to form an appropriate light spot on the surface of a traveling sheet-like object. At this time, if the scanning width (inspection width) is extremely large, the scanning speed will change between the edges and the center, so by installing multiple optical systems to narrow the inspection width, it is possible to completely inspect wide sheet materials. It can be done. In the present invention, an improvement is made so that the diameter of the light spot when the laser beam reaches the surface of the sheet-like object can be adjusted. That is, the first point of improvement lies in the light projecting means, which has a plurality of optical paths with different combinations of condensing lenses, prisms, and/or reflecting mirrors. When the diameter of the light spot is increased, it becomes difficult to detect minute surface defects on the sheet-like material. For example, when the diameter of the light spot is about 0.2 to 1.0 mm, the detection sensitivity for air bubbles is the highest among the defects of the sheet-like object. On the other hand, when the optical spot diameter is adjusted to 1.3 mm or more, bubble defects with a low probability of becoming a large surface defect are hardly detected, and decomposed foreign substances having a relatively large surface defect are detected. Therefore, as a light projecting means, an observation system with a spot diameter of about 0.2 to 0.8 mm and a spot diameter of 1.3 mm are used.
By having an observation system of about 2 mm to 2 mm,
It is possible to measure the total number of point defects, the number of decomposed foreign substances, etc. on a sheet-like object, and when combined with a spot diameter of about 1.0 to 1.3 mm, the total extent of these defects can be determined by simple calculations. Also, when it is necessary to increase the overall detection sensitivity, it is advantageous to use a light source with a short wavelength.
As explained above, it is preferable to increase the output and to decrease the spot diameter. The light-receiving means in the device of the present invention has a light-receiving surface below the scanning line of the light spot, and when the sheet-like material has no defects and the light simply passes through it, the light does not reach the photomultiplier tube serving as the light-receiving element. Install a shielding plate on the light receiving surface to prevent it from being hit. If there is a defect in the sheet-like material, the transmitted light is scattered, and a direct reception method using a diffuser plate is preferable, in which only the scattered light is received by the light-receiving element. This is because sheet-like materials such as plastic films have high transparency and require a high degree of reception of scattered light. In the improved device of the present invention, the arrangement of the shielding plate can be adjusted, and by increasing the shielding area, the amount of scattered light reaching the light receiving element can be reduced, and the detection sensitivity can be lowered. At this time, air bubbles and fish eyes, which are easily scattered defects, have a significant decrease in light intensity when the shielding area is increased, so by adjusting the shielding amount, it is possible to distinguish between bubbles and fish eyes and defects caused by decomposed foreign matter that have a low decrease in light intensity. can. The shielding plate is 1 to 2 times larger than the spot diameter.
mm wide, and cover the light-receiving surface with a non-light-transmitting material, such as black tape, about 3 to 5 mm wide. In order to observe bubbles and fish eyes in particular, a black tape can be pasted on the scanning line of the light spot. In addition, to mainly observe decomposed foreign substances, attach two more black tapes in parallel to this black tape.
It is best to attach the main black tape to the center of the book.
At this time, by appropriately adjusting the distance between the black tape and the other tape, it is possible to separate and identify surface defects of the sheet-like object from changes in the amount of received light. For example, if the light-receiving interval between the main tape and another sub-tape is about 1 mm and the width of the main tape is about 5 mm, the detection sensitivity of decomposed foreign matter will be higher than the detection sensitivity of air bubbles and fish eyes. Therefore, in the present invention, by providing the light-receiving surface with a mechanism that can adjust the shielding area, it is possible to select a surface defect to be observed. Specifically, a shielding light amount adjusting means having a mechanism in which a fixed shielding plate is placed in the center and a set of shielding plates provided on the sides can be slid so as to change the distance between the light receiving surfaces can be exemplified. Of course, the effective shielding amount (projection amount) can also be adjusted by rotating the pair of shielding plates so that the light receiving surface is inclined instead of sliding. Another simple method is to prepare shielding means with various shielding amounts in advance and attach the necessary ones to the light-receiving surface in a removable manner. When the optical system is adjusted so that the light emitted from the light projecting means is focused between the sheet-like object and the light projecting means, the light that passes through the sheet-like object is expanded, and the light receiving surface is smaller than the spot diameter. The width of the light at the spot is expanded (the spot diameter is observed as the width of the scanned light beam).
Therefore, this magnification ratio is the distance between the focal point and the light receiving means (light receiving surface) relative to the distance between the focal point and the sheet-like object. By moving the focal point closer to the sheet-like object or moving the light receiving means away from the sheet-like object, the magnification can be increased, and by reversing the change in relative distance, the magnification can be decreased. can. As the magnification increases, the density of scattered light due to surface defects decreases, making it easier to detect decomposed foreign substances based on detection sensitivity and scattering effects. In order to mainly detect decomposed foreign substances, the magnification is preferably 2 times to 10 times, particularly 3 times to 8 times. When the magnification is increased, it becomes difficult to distinguish between decomposed foreign matter that has low scattering properties and air bubbles and fish eyes that are easily scattered. The present invention will be explained with reference to the drawings. FIG. 1 is a perspective view showing an outline of the apparatus of the present invention. A sheet-like material (not shown) is run between the light projecting means 10 and the light receiving means 20 by a known running means (not shown). As the traveling means, a group of rolls can be used, which unrolls the rolled sheet material on one hand and inspects the surface defects while rolling it up on the other hand. Of course, the light emitting means, the light receiving means, the photoelectric conversion means, and the detecting means can be provided in the process of manufacturing the sheet-like object, and the manufacturing means can be used as the means for moving the sheet-like object. The light projecting means includes a light projector 12 that includes a laser light source such as argon or helium-neon, a generator, a prism, a lens, etc., and a vibrating mirror 16 that causes the laser light emitted from the projector to reach a light receiving surface.
This vibrating mirror can perform high-speed scanning by applying vibrations up to several kHz. Equivalent laser beam scanning is possible by rotating a polygon mirror at high speed instead of the vibrating mirror. 1st
The figure shows an example in which two projectors and vibrating mirrors are arranged in one row in the width direction of a sheet, and the scanning width is set to 1/2 of the sheet width. In addition, the two sets (4 pieces) of optical systems have different lens systems and have two different spot diameters (widths of scanning light beams) on the surface of the sheet-like object, allowing the detection circuit to identify defects on the surface of the sheet-like object. It is. In order to change the spot diameter and adjust the detection sensitivity of surface defects, the projector with a different lens system can be replaced. In this way, the amount of light can be adjusted. The laser beam passes through a sheet-like object traveling through a vibrating mirror and reaches the light receiving means 20. As shown in FIG. 2, the light receiving means is provided with a means for blocking transmitted light between a wide slit 22 corresponding to the position of the scanning light and a photoelectron amplifier tube 28 that receives the light passing through the slit. When the transmitted light passes through a sheet-like material with no surface defects, the fixed shielding plate 24 blocks the transmitted light so that the light does not directly hit the photomultiplier tube. Further, when the transmitted light passes through a surface defect of the sheet-like object and is scattered, the transmitted light passes through the gap between the rotating shielding plate 26 for adjusting the light amount and the fixed shielding plate 24 and reaches the photomultiplier tube. At this time, since the rotating shielding plate is inclined with respect to the direction of the transmitted light, the amount of light is adjusted by adjusting the rotation angle (inclination angle). As a means for adjusting the amount of transmitted light, a slidable shielding plate may be provided in place of the rotating shielding plate shown in FIG. 2 so that the gap between the rotary shielding plate and the fixed shielding plate can be changed. Known means including rack gears can be used for sliding. The light receiving means is placed on the elevating means 40, and the distance between the sheet-like object and the light receiving surface can be changed. When the focal point of the laser beam is located between the sheet-like object and the projector, the magnification of the transmitted light can be changed by the elevating means. At this time, if a method of replacing the lens of the projector is also used, the magnification ratio can be changed over a wider range. FIG. 3 is a plan view of the apparatus shown in FIG. 1, with only the optical system being developed. Light generated from a laser light source 11 passes through lenses 13 and 14 and is scanned by a vibrating mirror 16. Then, if necessary, the light that has passed through the sheet-like object S through the plane mirrors M and M' passes through the slit 22 of the light receiving means, and then the amount of light that has passed through the gap between the shielding plates 24 and 26 is detected by the photoprinter 28. . The present invention will be further explained below with reference to Examples. Example 1 In the optical system shown in Fig. 3, the beam diameter of the laser (He-Ne) light was changed by changing the lens, and a polyethylene terephthalate 2 with a thickness of 70 μm was used.
The possibility of identifying defects on the surface of axially stretched films was investigated. Photosensitivity is determined by converting transmitted light into an electrical signal, compared to noise caused by light transmitted through a defect-free sheet material, and scattered light with various defects.

【表】＊＊シート状物表面におけるビームの直径
(走査幅)
による電気信号レベルとの比として表示する。結
果を第１表に示したが、スポツト径が0.9mmまで
は気泡による欠点が高感度で検出でき、またスポ
ツト径1.6mm及び２mmでは分解異物の検出が容易
となることが判明した。実施例２ 180μｍの厚さをもつポリエチレンテレフタレ
ート２軸延伸フイルムとして、気泡（大きさの異
なる２種）、フイツシユアイ及び分解異物をもつ
ものを試料とし、これらのフイルムシートの欠点
の検出感度を試験した。光源はHe−Ne（２ｍＷ）
を使用し、スポツト径を2.5mm（一定）とし、固
定遮蔽板の幅を3.4及び５mmとし、また別な遮蔽
板（回転又は摺動遮蔽板に相当する）との間隙を
１mm及び５mmと変えて各々の表面欠点による検出
感度を電気信号として検知した。結果を第２表に
示す。この表より、実験条件、及びでは気
泡欠点を他の欠点と識別でき、実験は３種の欠
点を夫々分離して検知できることが判る。[Table] ** Beam diameter on the surface of the sheet material
(scan width)
It is displayed as a ratio of the electrical signal level. The results are shown in Table 1, and it was found that defects due to air bubbles could be detected with high sensitivity up to a spot diameter of 0.9 mm, and decomposed foreign matter could be easily detected with spot diameters of 1.6 mm and 2 mm. Example 2 A polyethylene terephthalate biaxially stretched film having a thickness of 180 μm with bubbles (two types of different sizes), fissures, and decomposed foreign matter was used as a sample, and the detection sensitivity of defects in these film sheets was tested. . Light source is He-Ne (2mW)
was used, the spot diameter was set to 2.5 mm (constant), the width of the fixed shield plate was set to 3.4 and 5 mm, and the gap with another shield plate (corresponding to a rotating or sliding shield plate) was changed to 1 mm and 5 mm. The detection sensitivity due to each surface defect was detected as an electrical signal. The results are shown in Table 2. From this table, it can be seen that under the experimental conditions, the bubble defect can be distinguished from other defects, and that the experiment can detect the three types of defects separately.

【表】実施例３光学レンズ及び受光手段を昇降させてスポツト
径と受光面に於ける透過光径との比である欠点拡
大率を種々変化させて、実施例２のフイルムの表
面欠点フイツシユアイと分解異物との識別を検討
した結果を第３表に示す。[Table] Example 3 By raising and lowering the optical lens and the light-receiving means and varying the defect enlargement ratio, which is the ratio between the spot diameter and the diameter of transmitted light on the light-receiving surface, the surface defect fixing eye of the film of Example 2 was investigated. Table 3 shows the results of examining the identification of decomposed foreign substances.

【表】第３表の結果から、散乱性の大きいフイツシユ
アイと散乱性の低い分解異物とは、その欠点を拡
大率の変化から識別できることが判明した。実施例４光源の波長を１ｍＷのHe−Neから５ｍＷのア
ルゴンに変えると、検出感度が高められる。この
感度の増加はシート状物の表面欠点とは無関係で
ある。結果を第４表に示した。[Table] From the results in Table 3, it was found that the defects of highly scattering fish eyes and low scattering decomposed foreign substances can be distinguished from the change in magnification. Example 4 Detection sensitivity is increased by changing the wavelength of the light source from 1 mW He-Ne to 5 mW Argon. This increase in sensitivity is independent of surface defects in the sheet. The results are shown in Table 4.

【表】【table】

【表】【table】【図面の簡単な説明】[Brief explanation of drawings]

第１図は本発明の装置の斜視図である。第２図
は受光器の遮蔽手段の概要を示す横断面図（部
分）である。また第３図は本発明の装置の光学系
路の説明図である。 FIG. 1 is a perspective view of the device of the invention. FIG. 2 is a cross-sectional view (part) showing an outline of the shielding means of the light receiver. FIG. 3 is an explanatory diagram of the optical system path of the apparatus of the present invention.

【特許請求の範囲】[Claims]

１酸化銅（CuO）に金（Au）が0.1〜10重量％
含まれるものをガス感応体として用いることを特
徴とするCOセンサ。２ガス感応体が加圧成型し、焼成して得られる
焼結体、またはペーストを印刷して焼結して得ら
れる焼結膜であることを特徴とする特許請求の範
囲第１項記載のCOセンサ。 1 0.1-10% by weight of gold (Au) in copper oxide (CuO)
A CO sensor characterized by using the contained substance as a gas sensitive body. 2. The CO according to claim 1, wherein the gas sensitive body is a sintered body obtained by pressure molding and firing, or a sintered film obtained by printing and sintering a paste. sensor.

Claims

焦点とシート状物との距離に対する該焦点と受光
面との距離を相対的に変化せしめ得るように受光
手段の位置を調整する手段を有する特許請求の範
囲第１項記載のシート状物の欠点検出装置。Disadvantages of the sheet-like article according to claim 1, which has means for adjusting the position of the light-receiving means so that the distance between the focal point and the light-receiving surface can be changed relative to the distance between the focal point and the sheet-like object. Detection device.