JP2011145082A - Surface defect inspection device for sheet-like object - Google Patents
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本発明は、透明体のシート状物表面の凹凸状欠陥をインラインで検出および判定する低コストの検査装置に関する。 The present invention relates to a low-cost inspection apparatus that detects and determines an irregular defect on the surface of a transparent sheet in-line.
液晶等に用いる光学フィルムや電子機器部品等に用いる高機能性フィルムは、近年ますます異物や欠陥に対する要求規格が厳しくなりつつあり、これらのシート状物はクリーンルームで製造され、製造ライン中にある欠陥検査機によってシート状物の欠陥に関する品質の管理が行われている。しかし、ロール等に付着した異物が原因となってシート状物表面に凹み欠陥や凸状欠陥等（以下、凹凸状欠陥と称す）が発生することがある。そのため、工程内には光の透過濃度変化によって検知する欠陥検査機が設置されているが、この検出方法は光を遮る付着異物等には有効であるが、凹凸状欠陥を見逃すことがある。出荷前の目視検査で品質規格外の凹凸状欠陥が発見されることもあり、その場合、膨大な廃棄損出や機会損出につながるといった問題があった。また、目視検査でも凹凸状欠陥を見逃すリスクがあり、多大な損出をもたらす恐れがある。 In recent years, optical film used for liquid crystal, etc., and high-functional films used for electronic equipment parts, etc., are increasingly demanding standards for foreign matters and defects, and these sheet-like materials are manufactured in a clean room and are in the production line. Quality control regarding defects in sheet-like materials is performed by a defect inspection machine. However, a dent defect or a convex defect (hereinafter referred to as a concavo-convex defect) may occur on the surface of the sheet-like material due to a foreign matter adhering to a roll or the like. For this reason, a defect inspection machine that detects the change in light transmission density is installed in the process, but this detection method is effective for adhering foreign matter and the like that block light, but it sometimes misses uneven defects. In some cases, irregular defects outside the quality standards are discovered by visual inspection before shipment, which leads to a problem of enormous disposal loss and opportunity loss. In addition, there is a risk of missing the irregular defects even in the visual inspection, and there is a risk of causing great loss.
この問題を解決するため、シート状物のライン中で、走行方向から蛍光灯の直線状の光を傾けて投射し、透過光をＣＣＤカメラで明暗信号として取り込み、光量ムラを補正しながら打痕等の凹凸状欠陥を検査する方法（例えば、特許文献１参照）が提案されている。しかしながら、曲率変化が小さな凹凸状欠陥は、蛍光灯等で構成した直線状の光では平行性に劣るため、欠陥がないシート状物の透過光との差異が小さく、欠陥を見逃す場合があるといった問題があった。 In order to solve this problem, in the line of sheet-like material, the linear light of the fluorescent lamp is projected obliquely from the running direction, the transmitted light is captured as a light / dark signal by the CCD camera, and the dent is made while correcting the unevenness of the light quantity. A method for inspecting uneven defects such as the above has been proposed (for example, see Patent Document 1). However, the uneven defect with small curvature change is inferior in parallelism with linear light composed of a fluorescent lamp or the like, so that the difference from the transmitted light of the sheet-like material having no defect is small and the defect may be overlooked. There was a problem.
また、シート状物のライン中で、走行方向からキセノンランプ等の点光源から平行化した均一な平行光を照射し、反射光をスクリーンに投影させ、ＣＣＤカメラで撮像した画像を演算処理して、シート状物のスジ等の表面欠陥を検査する方法（例えば、特許文献２参照）が提案されている。しかしながら、この方法は、照明装置の構成にコストがかかり、さらに、広幅のシート状物を検査する際には、複数台の照明装置と撮像手段が必要であるため、非常に高価な検査装置となって採算が合わないといった問題があった。 Also, in the line of sheet-like material, irradiate uniform parallel light parallel from a traveling light source from a point light source such as a xenon lamp, project the reflected light on a screen, and process the image captured by the CCD camera. A method for inspecting surface defects such as streaks of a sheet-like material (for example, see Patent Document 2) has been proposed. However, this method is costly for the configuration of the illumination device, and moreover, when inspecting a wide sheet-like object, a plurality of illumination devices and imaging means are required. There was a problem that it was not profitable.
本発明は、従来の技術の上記問題点を解決し、透明体シート状物表面に発生した曲率変化の小さな凹凸状欠陥でも漏れなく検出し、しかも、比較的低コストで構成できる信頼性の高い欠陥検査装置を提供することを目的としている。 The present invention solves the above-mentioned problems of the prior art, detects irregularities with a small curvature change occurring on the surface of a transparent sheet-like material without omission, and has a high reliability that can be configured at a relatively low cost. The object is to provide a defect inspection apparatus.
本発明者らは、鋭意検討した結果、上記課題を解決できることを見出し、本発明を完成するに至った。 As a result of intensive studies, the present inventors have found that the above problems can be solved, and have completed the present invention.
すなわち本発明は、走行する透明体のシート状物表面に発生した凹凸状の欠陥の検査において、
該シート状物の幅方向から平行光を斜めに透過させて広範囲を照射する照明手段と、
透過した光を光学的に圧縮させる配置で結像させるスクリーンと、
該スクリーンに結像した画像を明暗信号として検出する撮像手段と、
明暗信号のレベルをしきい値によって凹凸状欠陥として検知し、凹凸状欠陥の寸法及び形状を判定する信号処理手段と、
を具備することを特徴とするシート状物の表面欠陥検査装置に関する。
That is, the present invention, in the inspection of irregular defects generated on the surface of the traveling transparent sheet,
Illumination means for irradiating a wide area by transmitting parallel light obliquely from the width direction of the sheet-like material;
A screen that forms an image in an arrangement that optically compresses the transmitted light; and
Imaging means for detecting an image formed on the screen as a light and dark signal;
A signal processing means for detecting a level of a light / dark signal as a concavo-convex defect by a threshold and determining a size and shape of the concavo-convex defect;
It is related with the surface defect inspection apparatus of the sheet-like material characterized by comprising.
好ましい実施態様としては、前記照明手段の光源のシート状物に入射する入射角θが、１０°〜２５°であることを特徴とするシート状物の表面欠陥検査装置に関する。 As a preferred embodiment, the present invention relates to an apparatus for inspecting a surface defect of a sheet material, wherein an incident angle θ incident on the sheet material of the light source of the illuminating means is 10 ° to 25 °.
好ましい実施態様としては、前記撮像手段に一次元イメージセンサを用い、スキャン毎の明暗信号を前記信号処理手段によって一定ライン数を更新しながら蓄積し、しきい値を越えたライン数をシート状物の走行方向の欠陥の大きさとして検知し、欠陥の寸法を判定することを特徴とするシート状物の表面欠陥検査装置に関する。 As a preferred embodiment, a one-dimensional image sensor is used for the image pickup means, and a light / dark signal for each scan is accumulated while updating a certain number of lines by the signal processing means, and the number of lines exceeding a threshold value is stored in a sheet-like object. The present invention relates to a surface defect inspection apparatus for a sheet-like material, characterized in that it is detected as the size of a defect in the traveling direction of the sheet and the dimension of the defect is determined.
さらに本発明は、上記記載の表面欠陥判別装置を用いて、上記シート状物表面に発生した凹凸状の欠陥の寸法及び形状を判別することを特徴とする、欠陥判別方法に関する。 Furthermore, the present invention relates to a defect determination method characterized by determining the size and shape of the uneven defect generated on the surface of the sheet-like object using the surface defect determination apparatus described above.
本発明によれば、透明体シート状物表面の曲率変化の小さな凹凸状欠陥でも漏れなく検出し、比較的単純な信号処理によって欠陥形状をリアルタイムに判定することにより、欠陥の要因となる工程異常を早期に発見して損出拡大を防止し、信頼性の高い品質管理ができるという効果を奏する。 According to the present invention, a process abnormality that causes a defect is detected by detecting even a concave-convex defect with a small curvature change on the surface of a transparent sheet, and determining the defect shape in real time by relatively simple signal processing. It is possible to detect the problem at an early stage, prevent the loss from spreading, and achieve the effect of reliable quality control.
本発明に係わる透明体シート状物の欠陥検査装置は、走行する透明体のシート状物表面に発生した凹凸状の欠陥の検査において、該シート状物の幅方向から平行光を斜めに透過させて広範囲を照射する照明手段と、透過した光を光学的に圧縮させる配置で結像させるスクリーンと、該スクリーンに結像した画像を明暗信号として検出する撮像手段と、明暗信号のレベルをしきい値によって凹凸状欠陥として検知し、凹凸状欠陥の寸法及び形状を判定する信号処理手段とを具備することを特徴としている。凹凸状欠陥の寸法及び形状を判定する場合は、幅方向に系統的に歪んだ画像を補正することが好ましい。 The defect inspection apparatus for a transparent sheet according to the present invention allows parallel light to be transmitted obliquely from the width direction of the sheet in the inspection of uneven defects generated on the surface of the traveling transparent sheet. The illumination means for irradiating a wide area, the screen for forming an image in an arrangement for optically compressing the transmitted light, the imaging means for detecting the image formed on the screen as a light / dark signal, and the level of the light / dark signal It is characterized by comprising signal processing means for detecting as a concavo-convex defect by a value and determining the size and shape of the concavo-convex defect. When determining the size and shape of the concavo-convex defect, it is preferable to correct an image systematically distorted in the width direction.
ここで、凹凸状欠陥とは、シート状物に異物などが押し当てられた面が、湾曲して凹み、その反対面が凸状に膨らんだ欠陥をいう。 Here, the concavo-convex defect refers to a defect in which a surface on which a foreign substance or the like is pressed against a sheet-like object is curved and recessed, and the opposite surface bulges in a convex shape.
ここで、平行光とは、光束の各光線が重なることがなく、照明方向の光軸に対して平行に近い光線の成分で構成された光をいう。 Here, the parallel light refers to light composed of light components that are nearly parallel to the optical axis in the illumination direction without overlapping each light beam.
ここで、一定の拡がりがある平行光の光束をシート状物の幅方向から斜めに入射させることにより、シート状物では平行光の光束の直径よりも広い範囲を照射することができ、スクリーンに結像した画像は、照明手段に近いシート状物の手前側から奥側に向かって幅方向の画像が圧縮される。この画像の圧縮比率は、平行光の光束の拡がり角と入射角とシート状物の屈折率とスクリーンの角度によって決まり、数式演算によって補正が可能な系統誤差となる。 Here, by allowing a parallel light beam having a certain spread to enter obliquely from the width direction of the sheet material, the sheet material can irradiate a range wider than the diameter of the parallel light beam, and is applied to the screen. The formed image is compressed in the width direction from the near side of the sheet-like object close to the illumination unit to the far side. The compression ratio of the image is determined by the divergence angle and incident angle of the parallel light beam, the refractive index of the sheet-like material, and the screen angle, and is a systematic error that can be corrected by mathematical calculation.
ここで、スクリーンの角度は、平行光の光束の中心軸に対して垂直に配置することが画像の歪みが最も小さくなる点で好ましい。ここでの歪みは、平行光で照射したスクリーン面の中心軸から両外側に向かって像が拡大する現象であり、拡大比率は平行光の光束の拡がり角とスクリーン面上の結像範囲の直径に依存する。一般に平行光の光束の拡がり角は小さいため、これらの歪み量は無視できるレベルに小さいが、必要に応じて二次曲線での補正が可能である。また、二次曲線に合わせてスクリーンを凹面上に湾曲させることでも補正が可能である。 Here, it is preferable that the angle of the screen is arranged perpendicularly to the central axis of the light beam of the parallel light because the distortion of the image is minimized. The distortion here is a phenomenon in which the image expands from the central axis of the screen surface irradiated with parallel light toward both outer sides, and the expansion ratio is the divergence angle of the light beam of parallel light and the diameter of the imaging range on the screen surface. Depends on. In general, since the divergence angle of the parallel light beam is small, the amount of distortion is small enough to be ignored, but correction with a quadratic curve is possible if necessary. The correction can also be made by curving the screen on the concave surface in accordance with the quadratic curve.
また、シート状物上の照射範囲がスクリーン面上の結像範囲で光学的に圧縮されることにより、画像の光学濃度が強調され、撮像手段で検出すべき視野が狭くなり、少ない台数の撮像手段で対応できる点で優れている。 In addition, since the irradiation range on the sheet-like object is optically compressed within the imaging range on the screen surface, the optical density of the image is enhanced, the field of view to be detected by the imaging means is narrowed, and a small number of images are captured. It is excellent in that it can be handled by means.
一方、スクリーンに結像した画像の走行方向の大きさは、シート状物の速度が一定である限り、ＴＤの位置に依存した像の寸法の歪みは生じない。 On the other hand, as for the size of the image formed on the screen in the traveling direction, as long as the speed of the sheet-like material is constant, the distortion of the image size depending on the position of TD does not occur.
上記構成によれば、幅方向の斜め方向からシート状物の透過光をスクリーンに結像させた画像を一次元イメージセンサカメラ等で連続的に撮像して信号処理手段で検出することにより、光の照射エリア内で凹凸状の欠陥が通過した場合に、光の屈折方向の変化によって投影像の輝度に比例した明暗信号が変化することを利用して凹凸状欠陥の有無検知が可能となる。この明暗信号は、凹凸状欠陥の曲率変化が大きいほど変化が大きく、また、平行光の入射角度を浅くするほど大きくなる。 According to the above configuration, an image obtained by imaging the transmitted light of the sheet-like material on the screen from an oblique direction in the width direction is continuously imaged by a one-dimensional image sensor camera or the like and detected by the signal processing means. When a concave-convex defect passes through the irradiation area, the presence / absence of the concave-convex defect can be detected by utilizing the fact that a light / dark signal proportional to the luminance of the projected image changes due to the change in the light refraction direction. The light / dark signal changes as the curvature change of the concavo-convex defect increases, and increases as the incident angle of the parallel light decreases.
また、撮像した一次元の明暗信号を時系列に合成することによって欠陥等の二次元画像が得られ、合成する際に、幅方向の系統的な寸法の歪み補正によって歪みがない欠陥の画像として形状の判定が可能となる。 Also, two-dimensional images such as defects can be obtained by synthesizing the captured one-dimensional light and dark signals in time series, and when synthesizing, as a defect image without distortion by correcting distortion in the systematic dimension in the width direction. The shape can be determined.
従って、シート状物の幅方向から斜めに平行光を入射させることにより、シート状物を照射するエリア、すなわち、検査エリアが拡がることにより、さらに、スクリーン上で光学的に圧縮して結像させた画像を撮像させる方法により、少ない照明装置と撮像装置で広幅のシート状物を検査でき、低コストや省スペースの面で優れている。 Therefore, by collimating parallel light from the width direction of the sheet material, the area irradiated with the sheet material, that is, the inspection area is expanded, and further optically compressed and imaged on the screen. By using the method for picking up an image, a wide sheet-like object can be inspected with a small number of illumination devices and image pickup devices, which is excellent in terms of low cost and space saving.
本発明に係わる透明体シート状物の欠陥検査装置は、前記照明手段の光源のシート状物に入射する入射角θが、１０°〜２５°であることを特徴とするシート状物の表面欠陥検査装置に関する。入射角θとしては、１５°がもっとも好ましい。入射角θが浅いほど検査エリアは広くなるが、入射角θが、１０°より小さくなると、シート状物と空気層の境界面で反射する光が多くなってスクリーン上での明るさが減衰するため、明暗信号のレベルが全体的に低下する問題がある。また入射角θが２５°を超えると、曲率変化の小さな凹凸状欠陥と欠陥のない部位とのコントラストが低下して欠陥の検出が困難になり、また、平行光で照射するシート状物の範囲が狭くなって照明手段の追加が必要になるといった問題がある。 The defect inspection apparatus for a transparent sheet according to the present invention is characterized in that the incident angle θ incident on the sheet of the light source of the illuminating means is 10 ° to 25 °. It relates to an inspection device. The incident angle θ is most preferably 15 °. The shallower the incident angle θ, the wider the inspection area. However, when the incident angle θ is smaller than 10 °, the light reflected on the boundary surface between the sheet-like object and the air layer increases, and the brightness on the screen is attenuated. Therefore, there is a problem that the level of the light / dark signal decreases as a whole. In addition, when the incident angle θ exceeds 25 °, the contrast between the concave and convex defect having a small curvature change and the portion having no defect is lowered, and it becomes difficult to detect the defect, and the range of the sheet-like material irradiated with parallel light However, there is a problem that it becomes necessary to add illumination means.
前記照明手段の光源とシート状物との距離および入射角は、前記スクリーンに結像した凹凸状欠陥の部位と凹凸状欠陥がない部位との明暗の差が明暗信号で区別可能で、かつ、シート状物の幅方向で照明光の当たる検査範囲Ｗが最大となるように設定することを特徴としている。 The distance and incident angle between the light source of the illuminating means and the sheet-like object are such that the difference in brightness between the part of the uneven defect imaged on the screen and the part without the uneven defect can be distinguished by a light / dark signal, and It is characterized in that it is set so that the inspection range W where the illumination light hits is maximized in the width direction of the sheet-like material.
ここで、スクリーンに結像した凹凸状欠陥の部位と凹凸状欠陥がない部位との明暗の差は、凹凸状欠陥の曲率変化および平行光照明の入射角度に依存しており、曲率変化が小さな軽微な凹凸状欠陥でも明暗の光学的濃度差を生じさせるためには、入射角度をシート状物に対して浅くする方が有利である。入射角度を浅くすることで、軽微な凹凸状欠陥でも明暗の光学的濃度差を生じせしめ、シート状物の検査エリアも広くできる一方で、全体的に暗い画像となって地合ノイズも強調されるため、検出が必要な凹凸状欠陥と地合との明暗の差が区別できる範囲で入射角度を調整し、シート状物の検査エリアを設定することが好ましい。 Here, the difference in brightness between the portion of the uneven defect imaged on the screen and the portion without the uneven defect depends on the curvature change of the uneven defect and the incident angle of the parallel light illumination, and the curvature change is small. In order to produce an optical density difference between light and dark even with a slight uneven defect, it is advantageous to make the incident angle shallow with respect to the sheet-like material. By making the incident angle shallower, even a slight uneven defect can cause a difference in optical density between light and dark, and the inspection area of the sheet-like object can be widened. Therefore, it is preferable to set the inspection area of the sheet-like object by adjusting the incident angle within a range in which the difference in brightness between the uneven defect that needs to be detected and the texture can be distinguished.
また、照明手段とシート状物との距離を離すことにより、平行光の光束の拡がりに比例してシート状物の検査エリアが広くなり、照明輝度の減衰と設置スペースの制約範囲内で照明手段とシート状物との距離を離すことが好ましい。 Further, by separating the distance between the illumination means and the sheet-like object, the inspection area of the sheet-like object is increased in proportion to the spread of the parallel light beam, and the illumination means is within the limited range of attenuation of the illumination luminance and installation space. It is preferable to increase the distance between the sheet and the sheet.
従って、照明手段とシート状物との距離および入射角を、スクリーンに結像した明暗信号とシート状物の幅方向の検査エリアの条件から決定することにより、広い検査エリアで軽微な凹凸状欠陥を検出できる点で優れている。 Therefore, by determining the distance between the illumination means and the sheet-like object and the incident angle from the light / dark signal imaged on the screen and the conditions of the inspection area in the width direction of the sheet-like object, a slight uneven defect in a wide inspection area. Is superior in that it can be detected.
本発明に係わる透明体シート状物の欠陥検査装置は、前記撮像手段に一次元イメージセンサを用い、スキャン毎の明暗信号を前記信号処理手段によって一定ライン数を更新しながら蓄積し、しきい値を越えたライン数をシート状物の走行方向の欠陥の大きさとして検知し、欠陥の寸法を判定することが好ましい。欠陥の寸法を判定する場合には、各ラインの明暗信号の立ち下がり幅は予め設定した補正曲線に応じて歪みを補正して幅方向の欠陥の大きさとして抽出し、走行方向との大きさのデータと合成して二次元化することが好ましい。 The defect inspection apparatus for a transparent sheet according to the present invention uses a one-dimensional image sensor as the imaging means, accumulates a light / dark signal for each scan while updating a certain number of lines by the signal processing means, It is preferable to detect the number of lines exceeding the limit as the size of the defect in the running direction of the sheet-like material and determine the size of the defect. When determining the size of the defect, the falling width of the brightness signal of each line is extracted as the size of the defect in the width direction by correcting the distortion according to a preset correction curve, and the size with respect to the traveling direction. It is preferable to synthesize with two-dimensional data.
ここで、一次元イメージセンサは、スキャンレートに従って連続して一次元の明暗信号が出力され、エンコーダから換算したシート状物のライン速度に基づいて、一次元の明暗信号を信号処理装置で時系列に統合することによって二次元の画像情報が得られる。 Here, the one-dimensional image sensor outputs a one-dimensional light / dark signal continuously in accordance with the scan rate, and based on the line speed of the sheet-like material converted from the encoder, the one-dimensional light / dark signal is time-sequentially by a signal processing device. Two-dimensional image information can be obtained by integrating them into
ここで、明暗信号の立ち下がり幅の補正曲線は、平行光の入射角度とシート状物の屈折率とスクリーンの角度に依存し、スクリーンの角度を平行光の光束の中心軸に対して垂直に配置すれば二次曲線で近似できる。 Here, the correction curve for the falling width of the light / dark signal depends on the incident angle of the parallel light, the refractive index of the sheet-like material, and the angle of the screen, and the screen angle is perpendicular to the central axis of the light beam of the parallel light. If arranged, it can be approximated by a quadratic curve.
上記構成によれば、シート状物の走行方向の欠陥の大きさを明暗信号のライン数で検知し、シート状物の幅方向の欠陥の大きさを明暗信号の立ち下がり幅の補正後のデータを用いて、走行方向と幅方向のデータを合成することにより、欠陥の寸法や面積や形状を判定することが可能となる。 According to the above configuration, the size of the defect in the running direction of the sheet-like material is detected by the number of lines of the light / dark signal, and the size of the defect in the width direction of the sheet-like material is corrected data for the falling width of the light / dark signal. It is possible to determine the size, area and shape of the defect by combining the data in the running direction and the width direction using.
以下に、本発明に係わる透明体シート状物表面の凹凸状の欠陥検査装置に関して図１に基づいて説明する。尚、以下の実施形態は、本発明を具体化した一例であって、本発明の技術的範囲を限定する性格のものではない。 Below, the unevenness | corrugated defect inspection apparatus of the transparent body sheet-like material surface concerning this invention is demonstrated based on FIG. In addition, the following embodiment is an example which actualized this invention, Comprising: The thing of the character which limits the technical scope of this invention is not.
図１は、本発明の実施形態に係る透明体シート状物表面の凹凸状の欠陥検査装置の一例を示す模式図である。 FIG. 1 is a schematic view showing an example of a defect inspection apparatus for irregularities on the surface of a transparent sheet according to an embodiment of the present invention.
図１において、透明体シート状物５の走行方向をＭＤとし、幅方向をＴＤとし、その走行する透明体シート状物５のＴＤから平行光を斜めに透過させて広範囲を照射する照明手段１と、透過した光を光学的に圧縮させる配置で結像させるスクリーン２と、スクリーン２に結像した画像を明暗信号として検出する撮像手段３と、透明体シート状物５に図示していない凹凸状欠陥がある場合に、明暗信号のレベルをしきい値によって凹凸状欠陥として検知し、ＴＤに系統的に歪んだ画像を補正して凹凸状欠陥の形状を判定する信号処理手段４とを具備している。 In FIG. 1, illumination means 1 that irradiates a wide area by transmitting parallel light obliquely from the TD of the traveling transparent sheet 5, where the traveling direction of the transparent sheet 5 is MD and the width direction is TD. A screen 2 that forms an image in an arrangement that optically compresses the transmitted light, an image pickup unit 3 that detects an image formed on the screen 2 as a light / dark signal, and irregularities not shown in the transparent sheet 5 And a signal processing means 4 for detecting the level of the light / dark signal as a concavo-convex defect by a threshold value and determining the shape of the concavo-convex defect by correcting an image systematically distorted in TD when there is a dent defect. is doing.
また、透明体シート状物５の走行速度は、図示していない近傍のロールに設置したエンコーダから換算することができる。 The traveling speed of the transparent sheet 5 can be converted from an encoder installed on a nearby roll (not shown).
ここで、凹凸状欠陥とは、ロール上やニップロールにおいて、シート状物に異物などが押し当てられた面が、湾曲して凹み、その反対面が凸状に膨らんだ欠陥をいう。当然ながら、凹凸の向きや大きさや高低差は、接触する異物の大きさや硬さなどによって変化する。 Here, the concavo-convex defect refers to a defect in which a surface on which a foreign object or the like is pressed against a sheet-like material on a roll or a nip roll is curved and recessed, and the opposite surface bulges in a convex shape. As a matter of course, the direction, size, and height difference of the unevenness vary depending on the size and hardness of the foreign matter that comes into contact.
ここで、平行光とは、光束の各光線が重なることがなく、照明方向の光軸に対して平行に近い光線の成分で構成された光をいう。図１において、照明手段１の光束の出射窓の直径がφｓの場合、光束の中心が透明体シート状物５に交わる位置での直径は、光束の拡がり角と透明体シート状物５との距離に比例してφｔとなり、さらに、スクリーン２の表面上ではφｐに拡がる。照明手段１は、光束の各光線が重なり合わない平行光の照明とするために、キセノン光源のように点光源であることが好ましく、点光源の出射窓にコリメータレンズなどによって平行光とすることができる。 Here, the parallel light refers to light composed of light components that are nearly parallel to the optical axis in the illumination direction without overlapping each light beam. In FIG. 1, when the diameter of the light exit window of the light beam of the illuminating unit 1 is φs, the diameter at the position where the center of the light beam intersects the transparent sheet material 5 is the difference between the spread angle of the light beam and the transparent sheet material 5. It becomes φt in proportion to the distance, and further expands to φp on the surface of the screen 2. The illuminating means 1 is preferably a point light source such as a xenon light source so as to illuminate the parallel light so that the light beams of the light beams do not overlap, and the collimator lens or the like is used as the parallel light at the exit window of the point light source. Can do.
また、一定の拡がりがある平行光の光束を透明体シート状物５のＴＤから斜めの角度θで入射させることにより、透明体シート状物５では平行光の光束の直径φｔよりも広い範囲Ｗを照射することができ、スクリーン２に結像した画像は、照明手段１に近い透明体シート状物５の手前側から奥側に向かってＴＤの画像が圧縮される。この画像のＴＤの圧縮比率は、平行光の光束の拡がり角と入射角θと透明体シート状物５の屈折率とスクリーン２の角度によって決まり、数式演算によって補正が可能な系統誤差となる。平行光を斜めに入射させることによって、透明体シート状物５を通過、すなわち、照射範囲Ｗは、透明体シート状物５と光束の中心軸との交点ｃに対して、照明手段１の近い手前側が狭く、奥側が広くなり、そのときの平行光の入射角度は手前側がθ＋αとなり、奥側がθ−αとなる。 Further, by allowing a parallel light beam having a certain spread to enter from the TD of the transparent sheet 5 at an oblique angle θ, the transparent sheet 5 has a range W wider than the diameter φt of the parallel light beam. The image formed on the screen 2 is compressed as a TD image from the near side of the transparent sheet 5 close to the illumination unit 1 toward the far side. The TD compression ratio of this image is determined by the divergence angle of the parallel light beam, the incident angle θ, the refractive index of the transparent sheet 5 and the angle of the screen 2, and is a systematic error that can be corrected by mathematical calculation. By passing parallel light obliquely, it passes through the transparent sheet 5, that is, the irradiation range W is close to the illumination means 1 with respect to the intersection c between the transparent sheet 5 and the central axis of the light beam. The near side is narrow and the far side is wide, and the incident angle of parallel light at that time is θ + α on the near side and θ−α on the far side.
ここで、スクリーン２の角度は、平行光の光束の中心軸に対して垂直に配置することが画像の歪みが最も小さくなる点で好ましい。ここでの歪みは、平行光で照射したスクリーン２上面の中心点ｃ'から両外側に向かって像が拡大する現象であり、拡大比率は平行光の光束の拡がり角とスクリーン２面上の結像範囲の直径φｐに依存する。一般に平行光の光束の拡がり角は小さいため、これらの歪み量は無視できるレベルに小さいが、必要に応じて二次曲線での補正が可能である。また、二次曲線に合わせてスクリーンを凹面上に湾曲させることでも補正が可能である。スクリーン２の面は、拡散反射する材質を選択し、白色系で色斑がないことが好ましい。 Here, it is preferable that the angle of the screen 2 is arranged perpendicularly to the central axis of the light beam of the parallel light from the viewpoint that the distortion of the image is minimized. The distortion here is a phenomenon in which the image expands from the center point c ′ on the upper surface of the screen 2 irradiated with parallel light toward both outer sides, and the enlargement ratio is a result of the divergence angle of the parallel light beam and the connection on the screen 2 surface. Depends on the diameter φp of the image area. In general, since the divergence angle of the parallel light beam is small, the amount of distortion is small enough to be ignored, but correction with a quadratic curve is possible if necessary. The correction can also be made by curving the screen on the concave surface in accordance with the quadratic curve. For the surface of the screen 2, a material that diffuses and reflects is preferably selected and is preferably white and free from color spots.
また、透明体シート状物５上の照射範囲Ｗがスクリーン２面上の結像範囲の直径φｐで光学的に圧縮されることにより、画像の光学濃度が強調され、一次元のイメージセンサカメラなどの撮像手段３で検出すべき視野が狭くなり、少ない台数のイメージセンサカメラで対応できる点で優れている。図１において、シート状物上の照射範囲Ｗがスクリーン２面上の結像範囲の直径φｐに圧縮させることになる。 Further, the irradiation range W on the transparent sheet 5 is optically compressed by the diameter φp of the imaging range on the surface of the screen 2, thereby enhancing the optical density of the image, and a one-dimensional image sensor camera or the like. The field of view to be detected by the imaging means 3 is narrow, and this is excellent in that it can be handled by a small number of image sensor cameras. In FIG. 1, the irradiation range W on the sheet-like object is compressed to the diameter φp of the imaging range on the screen 2 surface.
一方、スクリーン２に結像した画像のＭＤの大きさは、透明体シート状物５の速度が一定である限り、撮像手段３である一次元のイメージセンサカメラの視野において、ＴＤの位置に依存した像の寸法の歪みは生じない。 On the other hand, the MD size of the image formed on the screen 2 depends on the position of the TD in the field of view of the one-dimensional image sensor camera that is the imaging means 3 as long as the speed of the transparent sheet 5 is constant. There is no distortion of the image dimensions.
上記構成によれば、ＴＤ斜め方向から透明体シート状物５の透過光をスクリーン２に結像させた画像を撮像手段３である一次元のイメージセンサカメラ等で連続的に撮像して信号処理手段４で検出ことにより、透明体シート状物５の光の照射範囲Ｗ内で凹凸状欠陥が通過した場合に、光の屈折方向の変化によって投影像の輝度に比例した明暗信号が変化することを利用して凹凸状欠陥の有無検知が可能となる。この明暗信号は、凹凸状欠陥の曲率変化が大きいほど光の屈折方向の影響が大きくなって明暗の差が大きくなり、また、平行光の入射角度θを浅くするほど明暗の差が大きくなる。 According to the above configuration, the image obtained by forming the transmitted light of the transparent sheet 5 on the screen 2 from the oblique direction of the TD is continuously imaged by the one-dimensional image sensor camera or the like which is the imaging means 3 to perform signal processing. As a result of detection by means 4, when an irregular defect passes within the light irradiation range W of the transparent sheet 5, the light / dark signal proportional to the brightness of the projected image changes due to the change in the direction of light refraction. Using this, it is possible to detect the presence or absence of irregular defects. In this light / dark signal, the greater the change in curvature of the concavo-convex defect, the greater the influence of the light refraction direction, and the greater the difference in light / dark, and the light / dark difference increases as the incident angle θ of the parallel light decreases.
また、撮像した一次元の明暗信号を信号処理手段４に蓄積して時系列に合成することによって欠陥等の二次元画像が得られ、合成する際に、ＴＤの系統的な寸法の歪み補正によって歪みがない欠陥の画像として形状の判定が可能となる。 Further, a two-dimensional image such as a defect is obtained by accumulating the captured one-dimensional light / dark signal in the signal processing means 4 and synthesizing in a time series, and when synthesizing, a systematic dimension distortion correction of TD is performed. The shape can be determined as a defect image without distortion.
従って、透明体シート状物５のＴＤから斜めに平行光を入射させることにより、透明体シート状物５の照射範囲Ｗ、すなわち、検査エリアが拡がることにより、さらに、スクリーン２上で光学的に圧縮して結像させた画像を撮像させる方法により、少ない照明手段１と撮像手段３で広幅の透明体シート状物５を検査でき、低コストや省スペースの面で優れている。 Therefore, by making parallel light incident obliquely from the TD of the transparent sheet-like material 5, the irradiation range W of the transparent sheet-like material 5, that is, the inspection area is expanded, and further optically on the screen 2. By the method of picking up an image formed by compression, the wide transparent sheet-like material 5 can be inspected with a small number of illumination means 1 and image pickup means 3, which is excellent in terms of low cost and space saving.
図１において、照明手段１の光源と透明体シート状物５との距離および入射角θは、スクリーン２に結像した凹凸状欠陥の部位と凹凸状欠陥がない部位との明暗の差が明暗信号で区別可能で、かつ、透明体シート状物５のＴＤで照明光の当たる検査範囲Ｗが最大となるように設定する。ここで、スクリーン２に結像した凹凸状欠陥の部位と凹凸状欠陥がない部位との明暗の差は、凹凸状欠陥の曲率変化および平行光照明の入射角度θに依存しており、曲率変化が小さな軽微な凹凸状欠陥でも明暗の光学的濃度差を生じさせるためには、入射角度θを透明体シート状物５に対して浅くする方が有利である。入射角度θを浅くすることで、軽微な凹凸状欠陥でも明暗の光学的濃度差を生じせしめ、透明体シート状物５の検査範囲Ｗも広くできる一方で、全体的に暗い画像となって地合ノイズも強調されるため、検出が必要な凹凸状欠陥と地合との明暗の差が区別できる範囲で入射角度θを調整し、透明体シート状物５の検査範囲Ｗを設定することが好ましい。 In FIG. 1, the distance between the light source of the illumination means 1 and the transparent sheet 5 and the incident angle θ are the difference in brightness between the uneven defect portion imaged on the screen 2 and the uneven defect portion. It is set such that it can be distinguished by a signal and the inspection range W to which the illumination light hits is maximized by the TD of the transparent sheet-like material 5. Here, the difference in brightness between the portion of the uneven defect imaged on the screen 2 and the portion having no uneven defect depends on the curvature change of the uneven defect and the incident angle θ of the parallel light illumination. However, in order to produce a light / dark optical density difference even with a slight uneven defect having a small thickness, it is advantageous to make the incident angle θ shallow relative to the transparent sheet 5. By making the incident angle θ shallow, even a slight uneven defect can cause a light / dark optical density difference, and the inspection range W of the transparent sheet 5 can be widened. Since the combined noise is also emphasized, it is possible to adjust the incident angle θ within a range in which the difference in brightness between the concavo-convex defect that needs to be detected and the ground can be distinguished, and to set the inspection range W of the transparent sheet 5 preferable.
凹凸状欠陥の厚みの最大の高低差が１〜３μｍで、直径が０．５ｍｍ〜３ｍｍの軽微な凹凸状欠陥を検出する場合、平行光の入射角度θは１０°〜２５°とし、平行光の光束の拡がり角が５°〜１０°とすることが好ましい。 In the case of detecting a slight uneven defect having a maximum height difference of 1 to 3 μm and a diameter of 0.5 mm to 3 mm, the incident angle θ of the parallel light is set to 10 ° to 25 °, and the parallel light The divergence angle of the luminous flux is preferably 5 ° to 10 °.
また、照明手段１と透明体シート状物５との距離を離すことにより、平行光の光束の拡がりに比例して透明体シート状物５の検査範囲Ｗが広くなり、照明輝度の減衰と設置スペースの制約範囲内で照明手段１と透明体シート状物５との距離を離すことが好ましく、照明手段１と透明体シート状物５との距離を５００ｍｍ〜１５００ｍｍとし、透明体シート状物５とスクリーン２との距離を２００ｍｍ〜６００ｍｍとすることが好ましい。また、透明体シート状物５と照明手段との距離Ｌは、２００ｍｍ以上離すことが好ましい。 Further, by separating the distance between the illumination means 1 and the transparent sheet 5, the inspection range W of the transparent sheet 5 is increased in proportion to the spread of the parallel light beam, and the illumination luminance is attenuated and installed. It is preferable to keep the distance between the illumination means 1 and the transparent sheet 5 within the space restriction range. The distance between the illumination means 1 and the transparent sheet 5 is 500 mm to 1500 mm, and the transparent sheet 5 The distance between the screen 2 and the screen 2 is preferably 200 mm to 600 mm. The distance L between the transparent sheet 5 and the illumination means is preferably 200 mm or more.
従って、照明手段１と透明体シート状物５との距離および入射角を、スクリーンに結像した明暗信号と透明体シート状物５のＴＤの検査範囲Ｗの条件から決定することにより、広い検査範囲Ｗで軽微な凹凸状欠陥を検出できる点で優れている。 Accordingly, by determining the distance and the incident angle between the illumination means 1 and the transparent sheet-like object 5 from the condition of the light / dark signal imaged on the screen and the inspection range W of the TD of the transparent sheet-like object 5, a wide inspection can be performed. It is excellent in that a slight uneven defect can be detected in the range W.
図１において、撮像手段３には一次元イメージセンサを用い、スキャン毎の明暗信号を信号処理手段４によって一定ライン数を更新しながら蓄積し、しきい値を越えたライン数を透明体シート状物５のＭＤの欠陥の大きさとして検知し、各ラインの明暗信号の立ち下がり幅は予め設定した補正曲線に応じて歪みを補正してＴＤの欠陥の大きさとして抽出し、ＭＤの大きさのデータと合成して二次元化し、欠陥の寸法や面積や形状を判定することが好ましい。 In FIG. 1, a one-dimensional image sensor is used for the image pickup means 3, and the light and dark signals for each scan are accumulated while the number of lines is updated by the signal processing means 4, and the number of lines exceeding the threshold value is in the form of a transparent sheet. Detected as the size of the MD defect of the object 5, the falling width of the brightness signal of each line is extracted as the size of the TD defect by correcting the distortion according to a preset correction curve. It is preferable to synthesize the two-dimensional data and determine the size, area, and shape of the defect.
ここで、撮像手段３の一次元イメージセンサは、スキャンレートに従って連続して一次元の明暗信号が出力され、図示していないエンコーダから換算した透明体シート状物５のライン速度に基づいて、一次元の明暗信号を信号処理装置４で時系列に統合することによって二次元の画像情報が得られる。信号処理装置４ではエンコーダから換算したライン速度とスキャンレートから、１スキャン当たりの距離をＭＤ最小単位とし、検知したライン数とかけ合わせて凹凸状欠陥のＭＤ長さとして換算できる。 Here, the one-dimensional image sensor of the imaging means 3 outputs a one-dimensional light / dark signal continuously according to the scan rate, and based on the line speed of the transparent sheet 5 converted from an encoder (not shown), Two-dimensional image information is obtained by integrating the original light and dark signals in time series by the signal processing device 4. The signal processing device 4 can convert the distance per scan as the MD minimum unit from the line speed and scan rate converted from the encoder, and convert it as the MD length of the concavo-convex defect by multiplying the detected number of lines.
ここで、明暗信号の立ち下がり幅の補正曲線は、平行光の入射角度θと透明体シート状物５の屈折率とスクリーン２の角度に依存し、スクリーン２の角度を平行光の光束の中心軸に対して垂直に配置すれば二次曲線で近似できる。 Here, the correction curve for the falling width of the light / dark signal depends on the incident angle θ of the parallel light, the refractive index of the transparent sheet 5 and the angle of the screen 2, and the angle of the screen 2 is the center of the luminous flux of the parallel light. If it is arranged perpendicular to the axis, it can be approximated by a quadratic curve.
上記構成によれば、透明体シート状物５のＭＤの欠陥の大きさを明暗信号のライン数で検知し、透明体シート状物５のＴＤの欠陥の大きさを明暗信号の立ち下がり幅の補正後のデータを用いて、ＭＤとＴＤのデータを合成することにより、欠陥の寸法や面積や形状を判定することが可能となる。 According to the said structure, the magnitude | size of the defect of MD of the transparent body sheet-like object 5 is detected by the number of lines of a brightness-and-darkness signal, and the magnitude | size of the TD defect of the transparent body sheet-like object 5 is the fall width of a brightness-and-darkness signal. By combining the MD and TD data using the corrected data, it is possible to determine the size, area, and shape of the defect.
図２は、スクリーン２の面を一次元イメージセンサカメラで検出した１スキャン分の明暗信号において、同寸法の円状の欠陥が結像位置によるＴＤの寸法歪みのイメージを示した図である。平行光の光束の中心軸で透明体シート状物５のｃ点を通過して結像したスクリーン上の点ｃ'で円状となる場合、照明手段１に近い手前側の点ｎの結像点ｎ'はＴＤに拡大し、奥側の点ｆの結像点ｆ'はＴＤに圧縮した画像となる。 FIG. 2 is a diagram showing an image of TD dimensional distortion caused by an image forming position of a circular defect of the same size in a light and dark signal for one scan in which the surface of the screen 2 is detected by a one-dimensional image sensor camera. When a point c ′ on the screen imaged through the point c of the transparent sheet 5 on the central axis of the light beam of parallel light is circular, the image of the point n on the near side near the illumination means 1 is formed. The point n ′ is enlarged to TD, and the image point f ′ of the back point f is an image compressed to TD.
図３、図４は、図２における点ｃ'と点ｎ'の位置にある画像を信号処理装置４で二値化した場合のイメージを示した一例である。図のマス目は、ＭＤおよびＴＤの最小単位を示しており、前者はライン速度とスキャンレートと決定し、後者はイメージセンサカメラの素子数と素子ピッチとカメラの結像倍率で決定され、欠陥で遮られないマス目を明部とし、欠陥で遮られたマス目を暗部Ｂとして示した。点ｃ'と点ｎ'の二値化画像から欠陥のＭＤおよびＴＤの最大寸法が検出でき、両者のＭＤ最大寸法はＹc＝Ｙnとなって同じ値となり、両者のＴＤ最大寸法はＸc＜Ｘnの関係となる。 3 and 4 are examples showing images when the signal processing device 4 binarizes the images at the positions of the points c ′ and n ′ in FIG. The squares in the figure indicate the minimum units of MD and TD. The former is determined by the line speed and the scan rate, and the latter is determined by the number of elements of the image sensor camera, the element pitch, and the imaging magnification of the camera. The squares that are not obstructed by the light are shown as bright parts, and the squares obstructed by the defects are shown as dark parts B. The maximum dimension of the MD and TD of the defect can be detected from the binarized image of the point c ′ and the point n ′, and the MD maximum dimension of both is the same value as Yc = Yn, and the maximum TD dimension of both is Xc <Xn It becomes the relationship.
（実施例１）
平均厚みが約５０μｍ、屈折率が１．５８のＰＣ系透明フィルムについて、最大高低差約１．５μｍ〜２．０μｍ，最大直径約０.５〜２．０ｍｍの楕円凹凸状欠陥サンプルを１００ｍｍ／秒で移動させ、５００Ｗのキセノン光源にコリメータで平行化した照明を用い、白色系スクリーンに結像した画像を４０００ビットの一次元ＣＣＤカメラで撮像する図１に示す構成とした。
Example 1
For a PC-based transparent film having an average thickness of about 50 μm and a refractive index of 1.58, an elliptical concave / convex defect sample having a maximum height difference of about 1.5 μm to 2.0 μm and a maximum diameter of about 0.5 to 2.0 mm is 100 mm / A configuration shown in FIG. 1 is used in which an image formed on a white screen is captured by a 4000-bit one-dimensional CCD camera using illumination that is moved in seconds and collimated with a 500 W xenon light source by a collimator.
平行光の入射角度を１５°とし、拡がり角約９°の照明光において、対象フィルムとの距離を１ｍとしたとき、対象フィルム上のＴＤ照明範囲を約８５０ｍｍとすることができ、対象フィルムから８００ｍｍ位置に平行光と垂直に配置したスクリーンでのＴＤ結像範囲は約３３０ｍｍとなった。 When the incident angle of the parallel light is 15 ° and the distance from the target film is 1 m in the illumination light having a spread angle of about 9 °, the TD illumination range on the target film can be about 850 mm. The TD image formation range on the screen arranged perpendicular to the parallel light at the 800 mm position was about 330 mm.
上述の条件で評価した結果、対象フィルム上のＴＤ照明範囲を欠陥が通過した際に、明暗信号が立ち下がりを生じ、二値化処理後に欠陥の寸法判定が可能であることを確認した。 As a result of the evaluation under the above-mentioned conditions, it was confirmed that when the defect passed through the TD illumination range on the target film, the light / dark signal fell, and the defect size could be determined after the binarization process.
図５は、対象フィルム上のＴＤ位置の各点とスクリーンと結像位置を示した図であり、二次式の曲線でフィッティングでき、この曲線を基に補正できることを確認した。 FIG. 5 is a diagram showing each point of the TD position on the target film, the screen, and the imaging position, and it was confirmed that fitting can be performed with a quadratic curve and correction can be made based on this curve.
（比較例１）
図６は、従来の凹凸状表面欠陥の検出方法に基づいて、平均厚みが約５０μｍ、屈折率が１．５８のＰＣ系透明フィルムについて、最大高低差約１．５μｍ〜２．０μｍ，最大直径約０.５〜２．０ｍｍの楕円凹凸状欠陥サンプルを１００ｍｍ／秒で移動させ、５００Ｗのキセノン光源にコリメータで平行化した照明を用い、白色系スクリーンに結像した画像を４０００ビットの一次元ＣＣＤカメラで撮像する構成とした。
(Comparative Example 1)
FIG. 6 shows a maximum height difference of about 1.5 μm to 2.0 μm and a maximum diameter of a PC-based transparent film having an average thickness of about 50 μm and a refractive index of 1.58 based on a conventional method for detecting uneven surface defects. An approximately 0.5-2.0 mm elliptical concave / convex defect sample is moved at 100 mm / second, and an image formed on a white screen using a collimator and a 500 W xenon light source is converted into a one-dimensional image of 4000 bits. It was set as the structure imaged with a CCD camera.
平行光はＭＤと垂直とし、入射角度を１５°とし、拡がり角約９°の照明光において、対象フィルムとの距離を１ｍとしたとき、対象フィルム上のＴＤ照明範囲を約２００ｍｍとなり、対象フィルムから８００ｍｍ位置に平行光と垂直に配置したスクリーンでのＴＤ結像範囲は約３１０ｍｍとなった。 When the parallel light is perpendicular to the MD, the incident angle is 15 °, and the illumination light with a divergence angle of about 9 ° is 1 m from the target film, the TD illumination range on the target film is about 200 mm. The TD image formation range on a screen arranged perpendicularly to the parallel light at a position of 800 mm from the center is about 310 mm.
対象フィルムからスクリーンに拡大して結像するため、凹凸状表面欠陥の画像は上記実施例１よりもボヤけた画像となった。 Since the image was enlarged and formed on the screen from the target film, the image of the uneven surface defect was a blurred image as compared with Example 1 above.
図７は、対象フィルム上のＴＤ照明範囲を約２００ｍｍの場合、１１００ｍｍ幅のフィルム全域を検査するために、照明手段とスクリーンと撮像手段を含む６式の光学系が必要となる一例を示した。上記実施例１の方法では、２式の光学系でフィルム全域の検査が可能となることを確認した。 FIG. 7 shows an example in which six optical systems including an illumination unit, a screen, and an imaging unit are required to inspect the entire film of 1100 mm width when the TD illumination range on the target film is about 200 mm. . In the method of Example 1, it was confirmed that the entire film could be inspected with the two optical systems.
１ 照明手段
２ スクリーン
３ 撮像手段
４ 信号処理手段
５ 透明体シート状物
ＭＤ 透明体シート状物の走行方向
ＴＤ 透明体シート状物の幅方向
θ 照明手段の平行光の中心の入射角
α 照明手段の平行光の拡がりに伴う入射角のズレ
φｓ 照明手段の光束の出射窓での直径
φｔ 照明手段の光束の中心と透明体シート状物が交わる位置での直径
φｐ 照明手段の光束がスクリーン上で結像した直径
Ｗ 透明体シート状物の平行光の照射範囲
ｃ 透明体シート状物と照明手段の光束の中心軸との交点
ｎ 透明体シート状物と照明手段の光束の中心軸との交点
ｆ 透明体シート状物と照明手段の光束の中心軸との交点
ｃ' スクリーン面での中心の結像点
ｎ' 照明手段の光束の手前端のスクリーン面での結像点
ｆ' 照明手段の光束の奥端のスクリーン面での結像点
Ｂ 二値化した画像で暗部のマス目
Ｙc 点ｃ上の欠陥の二値化画像のＭＤ最大寸法
Ｙn 点ｎ上の欠陥の二値化画像のＭＤ最大寸法
Ｘc 点ｃ上の欠陥の二値化画像のＴＤ最大寸法
Ｘn 点ｎ上の欠陥の二値化画像のＴＤ最大寸法
DESCRIPTION OF SYMBOLS 1 Illumination means 2 Screen 3 Imaging means 4 Signal processing means 5 Transparent body sheet MD Running direction of transparent body sheet TD Width direction of transparent body sheet θ Incident angle of center of parallel light of illumination section α Illumination section The incident angle shift due to the spread of parallel light φs Diameter at the exit window of the luminous flux of the illumination means φt Diameter at the position where the center of the luminous flux of the illumination means intersects the transparent sheet-like object φp Diameter of image W W Irradiation range of parallel light on transparent sheet c Intersection of transparent sheet and central axis of luminous flux of illumination means n Intersection of transparent sheet and central axis of luminous flux of illumination means f intersection of the transparent sheet and the central axis of the luminous flux of the illumination means c ′ imaging point at the center on the screen surface n ′ imaging point on the screen surface at the front end of the luminous flux of the illumination means f ′ of the illumination means On the screen surface at the far end of the luminous flux Image formation point B Binary image, dark squares Yc Maximum dimension of defect binary image on point c Yn Maximum dimension of defect binary image on point nn Defect on point c TD maximum size of binarized image of Xn TD maximum size of binarized image of defect on point n
Claims (4)
該シート状物の幅方向から平行光を斜めに透過させて広範囲を照射する照明手段と、
透過した光を光学的に圧縮させる配置で結像させるスクリーンと、
該スクリーンに結像した画像を明暗信号として検出する撮像手段と、
明暗信号のレベルをしきい値によって凹凸状欠陥として検知し、凹凸状欠陥の寸法及び形状を判定する信号処理手段と、
を具備することを特徴とするシート状物の表面欠陥検査装置。 In the inspection of irregularities generated on the surface of the traveling transparent sheet,
Illumination means for irradiating a wide area by transmitting parallel light obliquely from the width direction of the sheet-like material;
A screen that forms an image in an arrangement that optically compresses the transmitted light; and
Imaging means for detecting an image formed on the screen as a light and dark signal;
A signal processing means for detecting a level of a light / dark signal as a concavo-convex defect by a threshold and determining a size and shape of the concavo-convex defect;
An apparatus for inspecting a surface defect of a sheet-like material, comprising:
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| JP2010003823A JP2011145082A (en) | 2010-01-12 | 2010-01-12 | Surface defect inspection device for sheet-like object |
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