JP3036733B2 - Defect detection device for transparent objects - Google Patents
Defect detection device for transparent objectsInfo
- Publication number
- JP3036733B2 JP3036733B2 JP7066205A JP6620595A JP3036733B2 JP 3036733 B2 JP3036733 B2 JP 3036733B2 JP 7066205 A JP7066205 A JP 7066205A JP 6620595 A JP6620595 A JP 6620595A JP 3036733 B2 JP3036733 B2 JP 3036733B2
- Authority
- JP
- Japan
- Prior art keywords
- glass plate
- transparent body
- light
- inspection
- defect
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
- G01N21/892—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles characterised by the flaw, defect or object feature examined
- G01N21/896—Optical defects in or on transparent materials, e.g. distortion, surface flaws in conveyed flat sheet or rod
Landscapes
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
- Image Input (AREA)
- Image Processing (AREA)
- Image Analysis (AREA)
Description
【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION
【０００１】[0001]
【産業上の利用分野】本発明は、ガラス板等の板状透明
体の内部に存在する気泡や異物等を検出する方法及び装
置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting air bubbles, foreign matter and the like existing inside a transparent plate such as a glass plate.
【０００２】[0002]
【従来の技術】例えば写真乾板の支持体には透明なガラ
ス板が用いられている。このような目的で用いられるガ
ラス板には、透明であることの他に、表面に傷がないこ
と、内部に泡や異物が入っていないことが要求される。
このため従来より、１００μｍ程度の微小欠陥でも検出
できるように様々な検査装置が工夫されている。2. Description of the Related Art For example, a transparent glass plate is used as a support for a photographic dry plate. The glass plate used for such a purpose is required to be transparent, be free of scratches on its surface, and be free of bubbles and foreign substances inside.
For this reason, conventionally, various inspection devices have been devised so as to be able to detect even a minute defect of about 100 μm.
【０００３】特公昭５７−３７０２３号公報記載の検査
装置では、正常部分と欠陥部分とで光の反射率や透過率
が異なることを利用しており、走行するガラス板の幅方
向にスポット光を走査してその反射光あるいは透過光を
受光器で光電検出し、この検出出力に基づいて各種欠陥
の有無を評価している。[0003] The inspection apparatus described in Japanese Patent Publication No. 57-37023 utilizes the fact that the reflectance and transmittance of light are different between a normal portion and a defective portion. Scanning is performed, and the reflected light or transmitted light is photoelectrically detected by a light receiver, and the presence or absence of various defects is evaluated based on the detected output.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、上記検
査装置では、ガラス板の表面に付着した汚れやほこりの
影響を受けやすく、ガラス板の内部の４０μｍ程度の大
きさの欠陥を検出しようとした場合には、汚れであるの
か欠陥であるのかの識別が難しくなり実用化しにくいと
いう問題がある。また、装置が大型になり高価になると
いう問題もある。However, the above inspection apparatus is susceptible to dirt and dust adhering to the surface of the glass plate, and attempts to detect a defect of about 40 μm inside the glass plate. However, there is a problem in that it is difficult to distinguish whether it is a dirt or a defect, and it is difficult to put it to practical use. There is also a problem that the device becomes large and expensive.
【０００５】本発明は、上記問題点に鑑みてなされたも
ので、ガラス板等の板状の透明体内部の微小な欠陥を表
裏面に付着した汚れやほこり等の影響を受けずに検出す
るとともに、その装置を安価に提供することを目的とす
る。The present invention has been made in view of the above problems, and detects minute defects inside a plate-shaped transparent body such as a glass plate without being affected by dirt or dust attached to the front and back surfaces. It is another object of the present invention to provide the device at low cost.
【０００６】[0006]
【課題を解決するための手段】上記目的を達成するため
に、本発明の透明体の欠陥検出装置は、連続走行する透
明体の両端面から入射する検査レーザ光を、透明体の厚
み方向で発散させ、該透明体の厚みと直交する方向では
幅方向の中央部近傍で収束させるようにしたものであ
る。To achieve the above object, according to the Invention The defect detection device of the transparent body of the present invention is permeable to a continuously running
Inspection laser light incident from both ends of the clear body is
In the direction perpendicular to the thickness of the transparent body.
Is obtained by the so that converges in the vicinity of the central portion of the width direction.
【０００７】また、請求項２記載の透明体の欠陥検出装
置は、表裏面を平滑にした連続走行される板状の透明体
に、その幅方向の両端面から、透明体の表裏面で全反射
を繰り返しながら他方の端面に向かう検査光を入射する
投光器と、検査光の入射方向に沿った検査視野をもち、
透明体の表裏いずれかの面を通して透明体内部で散乱し
た散乱光を光電検出する受光器と、この受光器からの出
力に基づいて透明体に存在する欠陥を識別する処理手段
とから構成されたものである。Further, according to a second aspect of the present invention, there is provided a transparent body defect detecting apparatus in which a continuously running plate-shaped transparent body having a smooth front and back surfaces is provided on both front and back surfaces of the transparent body from both end surfaces in the width direction. It has a projector that enters the inspection light toward the other end face while repeating reflection, and an inspection field of view along the incident direction of the inspection light,
The photodetector is configured to photoelectrically detect scattered light scattered inside the transparent body through one of the front and back surfaces of the transparent body, and processing means for identifying a defect existing in the transparent body based on an output from the photodetector. Things.
【０００８】更に、請求項３記載の透明体の欠陥検出装
置は、投光器は、検査光としてレーザ光を放射するとと
もに、このレーザ光は透明体の厚み方向では発散するレ
ーザビームとして透明体に入射されるようにしたもので
ある。In a third aspect of the present invention, the projector emits a laser beam as inspection light, and the laser beam enters the transparent body as a laser beam diverging in the thickness direction of the transparent body. It is made to be done.
【０００９】また、請求項４記載の透明体の欠陥検出装
置は、レーザビームを透明体の厚みと直交する方向では
収束するビームとして透明体に入射するようにしたもの
である。According to a fourth aspect of the present invention, there is provided a transparent body defect detecting apparatus wherein a laser beam is incident on the transparent body as a beam converging in a direction perpendicular to the thickness of the transparent body.
【００１０】[0010]
【作用】表裏面が平滑にされた板状の透明体を連続走行
させ、その幅方向の両端面から、透明体の表裏面で全反
射を繰り返しながら他方の端面に向かう検査光を入射す
る。この検査光としてはレーザ光を用い、透明体の厚み
方向で発散するレーザビームとする。これにより、透明
体の厚み方向における検査光のパワー密度を一定にで
き、厚み方向における検出感度を一定にできる。また、
透明体の厚みと直交する方向ではレーザビームを収束さ
せたので、表裏面での全反射によって減衰する検査光の
パワー密度を補正し、均一にできるので、該方向におい
ても検出感度を一定にできる。The plate-shaped transparent body whose front and back surfaces are smoothed continuously travels, and inspection light is incident from both end surfaces in the width direction toward the other end surface while repeating total reflection on the front and back surfaces of the transparent body. As the inspection light, a laser beam is used, which is a laser beam diverging in the thickness direction of the transparent body. Thereby, the power density of the inspection light in the thickness direction of the transparent body can be made constant, and the detection sensitivity in the thickness direction can be made constant. Also,
Since the laser beam is converged in the direction orthogonal to the thickness of the transparent body, the power density of the inspection light attenuated by total reflection on the front and back surfaces can be corrected and made uniform, so that the detection sensitivity can be kept constant in the direction. .
【００１１】[0011]
【実施例】図１は、本発明の透明体の欠陥検出装置の基
本構造を概略的に表したものである。検査装置は、投光
器である投光ユニット２と、受光器であるラインセンサ
カメラ３と、このラインセンサカメラ３の検出信号を処
理する処理手段である処理部４とから構成されている。
本実施例では、板状の透明体として表裏面が平滑に研磨
されたガラス板５を用い、内部の泡や異物等の欠陥及び
表裏面の傷等の欠陥の検出を行う。ガラス板５は、図示
しないが搬送ローラや搬送ベルト等に載置されて矢印Ｘ
方向に連続的に搬送される。FIG. 1 schematically shows a basic structure of a transparent body defect detecting apparatus according to the present invention. The inspection apparatus includes a light emitting unit 2 as a light emitter, a line sensor camera 3 as a light receiver, and a processing unit 4 as processing means for processing a detection signal of the line sensor camera 3.
In this embodiment, a glass plate 5 whose front and back surfaces are polished smoothly as a plate-shaped transparent body is used to detect defects such as bubbles and foreign matter inside and defects such as scratches on the front and back surfaces. The glass plate 5 is placed on a transport roller or a transport belt (not shown) and
Conveyed continuously in the direction.
【００１２】投光ユニット２は、ユニットボックス７内
部に、白色光を放射するランプ等からなる光源８と、光
路折曲げ用の反射ミラー９，１０と、ビームエキスパン
ダ用の２枚のレンズ１１，１２とが組み込まれており、
搬送されるガラス板５の側方に配置されている。光源８
から放射された白色光は、２枚の反射ミラー９，１０を
介してレンズ１１，１２に入射される。レンズ１１，１
２は、白色光をガラス板５の厚み方向で絞り、検査光１
３としてユニットボックス７の側面に形成された開口７
ａからガラス板５の端面５ａに向かって照射する。The light projecting unit 2 includes a light source 8 such as a lamp for emitting white light, reflection mirrors 9 and 10 for bending the optical path, and two lenses 11 for a beam expander inside a unit box 7. , 12 are incorporated,
It is arranged on the side of the glass plate 5 to be conveyed. Light source 8
The white light radiated from is incident on the lenses 11 and 12 via the two reflecting mirrors 9 and 10. Lens 11, 1
2 is an inspection light 1 which squeezes white light in the thickness direction of the glass plate 5.
An opening 7 formed on the side surface of the unit box 7 as 3
a to the end face 5 a of the glass plate 5.
【００１３】ガラス板５の端面５ａに入射された検査光
１３は、図２に示すように、ガラス板５の内部を直進す
る。そして、ガラス板５の内部に気泡や異物等の欠陥１
５が存在すると、検査光１３は欠陥１５によって散乱さ
れ、ガラス板５の表裏面に放射される。また、検査光１
３は、ガラス板５が矢印Ｘ方向に移動している間に端面
５ａに入射されるので、ガラス板５の内部を全域に渡っ
て走査することになる。このように、検査光１３はガラ
ス板５の内部を進んで行って内部欠陥１５を検出するの
で、ガラス板５の表裏面に汚れやほこりが付着していて
も何ら検査に支障はなく、汚れやほこりの誤検出は発生
しない。The inspection light 13 incident on the end face 5a of the glass plate 5 travels straight inside the glass plate 5, as shown in FIG. Then, defects 1 such as air bubbles and foreign matter are found inside the glass plate 5.
When 5 exists, the inspection light 13 is scattered by the defect 15 and emitted to the front and back surfaces of the glass plate 5. In addition, inspection light 1
3 is incident on the end face 5a while the glass plate 5 is moving in the direction of the arrow X, so that the inside of the glass plate 5 is scanned over the entire area. As described above, since the inspection light 13 travels inside the glass plate 5 to detect the internal defect 15, even if dirt or dust adheres to the front and back surfaces of the glass plate 5, there is no problem in the inspection. False detection of dust and dust does not occur.
【００１４】ラインセンサカメラ３はガラス板５の上方
に配置されており、ガラス板５内部の欠陥１５によって
散乱された検査光１３を検出する。ラインセンサカメラ
３は、ＣＣＤ素子とこのＣＣＤ素子の検出範囲を広げる
ためのレンズとから構成されており、ガラス板５の内部
を通過する検査光１３の上部で、ガラス板５の幅方向の
全域に渡って散乱光を検出する検出視野１６を有してい
る。The line sensor camera 3 is disposed above the glass plate 5 and detects inspection light 13 scattered by a defect 15 inside the glass plate 5. The line sensor camera 3 includes a CCD element and a lens for expanding the detection range of the CCD element. The line sensor camera 3 covers the entire area in the width direction of the glass plate 5 above the inspection light 13 passing through the inside of the glass plate 5. And has a detection field of view 16 for detecting scattered light.
【００１５】処理部４は、ラインセンサカメラ３から入
力された検出信号を予め設定されているスレッシュホー
ルドレベルと比較し、検出信号がこのレベルを越えたと
きにガラス板５内部に欠陥１５があると評価する。そし
て、表示パネル等に欠陥があることを表示するととも
に、欠陥のあるガラス板５をライン上から取り除くよう
に指示する。このように、本検査装置は、投光ユニット
２とラインセンサカメラ３と処理部４とだけで構成され
ているので安価であり、また装置の小型化も可能とな
る。The processing section 4 compares the detection signal input from the line sensor camera 3 with a preset threshold level, and when the detection signal exceeds this level, there is a defect 15 inside the glass plate 5. Evaluate. Then, the fact that the display panel or the like has a defect is displayed, and an instruction is given to remove the defective glass plate 5 from the line. As described above, the present inspection apparatus includes only the light projecting unit 2, the line sensor camera 3, and the processing unit 4, so that it is inexpensive, and the apparatus can be downsized.
【００１６】上記実施例の検査装置は、光源として白色
光を用いているため、ガラス板の幅が広い場合にはガラ
ス板の幅方向の全域に検査光を届かせることができな
い。このような場合には、ガラス板の幅方向の両側方に
投光ユニットを設置し、両端面から検査光をガラス板の
内部に入射させるとよい。Since the inspection apparatus of the above embodiment uses white light as a light source, if the width of the glass plate is large, the inspection light cannot reach the entire region in the width direction of the glass plate. In such a case, it is preferable to install the light projecting units on both sides in the width direction of the glass plate, and to make the inspection light enter the inside of the glass plate from both end surfaces.
【００１７】また、さらに幅の広いガラス板の内部欠陥
を検出する場合には、検査光にレーザ光を用いるとよ
い。レーザ光は、パワー密度を高くできるので微小な欠
陥の検出が可能になるとともに、指向性がよいので後述
するように容易に好ましいビーム形状を得ることができ
る。レーザ光を検査光として用いた透明体の欠陥検出装
置の概略を図３に示す。Further, when detecting an internal defect of a glass plate having a wider width, it is preferable to use a laser beam as the inspection light. Since the power density of the laser beam can be increased, it is possible to detect minute defects, and the laser beam has good directivity, so that a preferable beam shape can be easily obtained as described later. FIG. 3 schematically shows a defect detection apparatus for a transparent body using laser light as inspection light.
【００１８】本実施例の検査装置は、矢印Ｘ方向に搬送
されるガラス板１８を挟むように側方に設置された投光
ユニット１９，２０と、前記実施例のものよりも検出視
野２１ａが幅方向で広げられたラインセンサカメラ２１
と、このラインセンサカメラ２１の検出信号が入力され
る処理部２２とから構成されている。ガラス板１８は、
図４及び図５に示すように、例えば厚みｔが５ｍｍであ
り幅Ｗが８００ｍｍとなっている。The inspection apparatus according to the present embodiment has light-emitting units 19 and 20 which are installed laterally so as to sandwich the glass plate 18 conveyed in the direction of the arrow X, and has a detection field of view 21a larger than that of the above-described embodiment. Line sensor camera 21 expanded in width direction
And a processing unit 22 to which a detection signal of the line sensor camera 21 is input. The glass plate 18
As shown in FIGS. 4 and 5, for example, the thickness t is 5 mm and the width W is 800 mm.
【００１９】投光ユニット１９は、ユニットボックス２
４の内部に、レーザ光を放射するレーザ発振器２５と、
光路折曲げ用の反射ミラー２６，２７と、第１ビーム形
状設定レンズ２８，第２ビーム形状設定レンズ２９，第
３ビーム形状設定レンズ３０，第４ビーム形状設定レン
ズ３１からなるレンズ群３２とが組み込まれており、ユ
ニットボックス２４の側面に形成された開口２４ａから
レーザ光を検査光３３としてガラス板１８の端面１８ａ
に向かって放射する。前記レーザ発振器２５としては、
例えばＨｅ−Ｎｅレーザを用いている。投光ユニット２
０は、投光ユニット１９と同様の構成であり、ガラス板
１８の内部に開口２０ａから検査光３４を入射する。The light projecting unit 19 includes the unit box 2
4, a laser oscillator 25 for emitting laser light,
Reflection mirrors 26 and 27 for bending the optical path, and a lens group 32 including a first beam shape setting lens 28, a second beam shape setting lens 29, a third beam shape setting lens 30, and a fourth beam shape setting lens 31 are provided. The laser light is used as inspection light 33 from an opening 24a formed on the side surface of the unit box 24 and the end surface 18a of the glass plate 18
Radiates towards. As the laser oscillator 25,
For example, a He-Ne laser is used. Floodlight unit 2
Reference numeral 0 denotes a configuration similar to that of the light projecting unit 19, and the inspection light 34 enters the inside of the glass plate 18 from the opening 20a.
【００２０】前記レンズ群３２を構成する第２ビーム形
状設定レンズ２９及び第４ビーム形状設定レンズ３１
は、ガラス板１８の厚み方向のレーザ光のビーム形状を
設定するためのものであり、例えば２個のシリンドリカ
ルレンズや、凸レンズとシリンドリカルレンズとの組み
合わせが用いられる。そして、図４に示すように、第２
ビーム形状設定レンズ２９及び第４ビーム形状設定レン
ズ３１を通過したレーザビームは、ガラス板１８の端面
１８ａの付近でビームウエスト３５が形成され、約４度
の角度で発散されて端面１８ａに入射される。このガラ
ス板１８の厚み方向で発散された検査光３３は、ガラス
板１８の内部を表裏面１８ｂ，１８ｃで全反射を繰り返
しながら進んでいく。これにより、厚み方向の欠陥の位
置による検出感度のバラツキを軽減できる。また、厚み
方向にパワー密度が一定なので、厚み方向の中央部にあ
る欠陥だけでなく、表裏面の近くに存在する欠陥も検出
できる。The second beam shape setting lens 29 and the fourth beam shape setting lens 31 constituting the lens group 32
Is for setting the beam shape of the laser light in the thickness direction of the glass plate 18, and for example, two cylindrical lenses or a combination of a convex lens and a cylindrical lens is used. Then, as shown in FIG.
The laser beam that has passed through the beam shape setting lens 29 and the fourth beam shape setting lens 31 forms a beam waist 35 near the end face 18a of the glass plate 18, diverges at an angle of about 4 degrees, and enters the end face 18a. You. The inspection light 33 diverged in the thickness direction of the glass plate 18 travels inside the glass plate 18 while repeating total reflection on the front and back surfaces 18b and 18c. Thereby, it is possible to reduce the variation in the detection sensitivity due to the position of the defect in the thickness direction. Further, since the power density is constant in the thickness direction, it is possible to detect not only a defect at the center in the thickness direction but also a defect near the front and back surfaces.
【００２１】また、第１ビーム形状設定レンズ２８及び
第３ビーム形状設定レンズ３０は、ガラス板１８の厚み
と直交する方向のレーザビーム形状を設定するためのも
のであり、やはり２個のシリンドリカルレンズや、凸レ
ンズとシリンドリカルレンズとの組み合わせが用いられ
る。この第１ビーム形状設定レンズ２８と第３ビーム形
状設定レンズ３０とを通過したレーザビームは、図５に
示すように、ガラス板１８の中央に向かって収束されて
いき、ガラス板１８の側端面１８ａからＷ／２の距離の
中央部１８ｄ付近にレーザウエスト３８が形成される。The first beam shape setting lens 28 and the third beam shape setting lens 30 are for setting a laser beam shape in a direction orthogonal to the thickness of the glass plate 18, and also have two cylindrical lenses. Alternatively, a combination of a convex lens and a cylindrical lens is used. The laser beam passing through the first beam shape setting lens 28 and the third beam shape setting lens 30 is converged toward the center of the glass plate 18 as shown in FIG. A laser waist 38 is formed near a central portion 18d at a distance of W / 2 from 18a.
【００２２】このようにレーザビームを収束させるの
は、ガラス板１８内部での検査光３３のパワー密度を一
定にして、ガラス板１８の幅方向のどの位置でも変わら
ない検出レベルで欠陥３６を検出するためである。レー
ザ光は、ガラス板１８内部を通過する間にそのパワー密
度が減衰していく。この減衰により、ガラス板１８の端
面１８ａ付近の欠陥による検査光３３の散乱と、中央部
１８ｄ付近の欠陥による検査光３３の散乱とでは散乱光
の光量が異なり、ラインセンサカメラ２１からの検出信
号のレベルが変化してしまう。そのため、処理部２２で
設定されるスレッシュホールドレベルも一定ではなく、
検査光３３の減衰に合わせなくてはならず、その制御が
複雑になってしまう。In order to converge the laser beam in this manner, the power density of the inspection light 33 inside the glass plate 18 is kept constant, and the defect 36 is detected at a detection level which does not change at any position in the width direction of the glass plate 18. To do that. The power density of the laser light is attenuated while passing through the inside of the glass plate 18. Due to this attenuation, the amount of the scattered light differs between the scattering of the inspection light 33 due to the defect near the end face 18a of the glass plate 18 and the scattering of the inspection light 33 due to the defect near the center 18d. Level changes. Therefore, the threshold level set by the processing unit 22 is not constant,
It is necessary to adjust to the attenuation of the inspection light 33, which complicates the control.
【００２３】また、端面１８ａ付近では検査感度が高く
なり過ぎて欠陥として評価されるレベル以下の微小な気
泡や異物をも検出してしまい、結果として誤検出となっ
て、本来合格品であるガラス板１８が不具合品として評
価されるという問題が発生する。In the vicinity of the end face 18a, the inspection sensitivity becomes too high, and even minute bubbles and foreign matters below the level evaluated as a defect are detected. There is a problem that the plate 18 is evaluated as a defective product.
【００２４】図６は、ガラス板１８の端面１８ａから、
約１５０ｍｍ，３００ｍｍ，４００ｍｍ（中央部１８
ｄ）の位置にそれぞれ配置した約６０μｍの大きさの欠
陥を検出し、そのときのラインセンサカメラ２１の検出
信号のＳ／Ｎ比を調べた実験結果を示すグラフである。
破線４０は、端面１８ａ付近のレーザ出力を約６ｍＷと
し、ガラス板１８の厚みと直交する方向の検査光の幅を
約３ｍｍ一定としてガラス板１８に入射させたときのも
のである。また実線４１は、端面１８ａ付近のレーザ出
力を破線４０と同様に約６ｍＷとし、ガラス板１８の厚
みと直交する方向の検査光の幅ＬＷ1 を端面１８ａ付近
で約９ｍｍ，中央部１８ｄ付近での幅ＬＷ 2 を約３ｍｍ
となるように収束させたものである。なお、両者ともに
ガラス板１８の厚み方向では、図４に示すように検査光
を発散させている。FIG. 6 shows a state in which the end surface 18a of the glass plate 18 is
About 150mm, 300mm, 400mm (Central part 18
A chip having a size of about 60 μm arranged at the position of d)
Detecting a defect and detecting the line sensor camera 21 at that time
9 is a graph showing an experimental result of examining the S / N ratio of a signal.
The broken line 40 indicates that the laser output near the end face 18a is about 6 mW.
And the width of the inspection light in the direction orthogonal to the thickness of the glass plate 18
When the light is made to enter the glass plate 18 with a constant value of about 3 mm,
It is. The solid line 41 indicates the laser output near the end face 18a.
The force is set to about 6 mW similarly to the broken line 40, and the thickness of the glass plate 18 is
The width LW of the inspection light in the direction perpendicular to the direction1Near the end face 18a
About 9mm, width LW near the center 18d TwoAbout 3mm
Are converged so that In addition, both
In the thickness direction of the glass plate 18, as shown in FIG.
Is diverging.
【００２５】このグラフによると、破線４０は端面１８
ａからの距離が遠くなるほどＳ／Ｎ比が減衰していくこ
とがわかる。また実線４１は、端面１８ａから中央部１
８ｄにかけてほぼ一定のＳ／Ｎ比となっている。これに
よれば、実線４１での検査光は破線４０に比べて全体的
にパワー密度が弱くなっていることが分かるが、このパ
ワー密度のレベルでも実用に不足がなく、実験では全域
において約４０μｍの大きさの欠陥でも正確に検出でき
た。これに対し破線４１では、端面１８ａ付近の検査光
が強く過ぎて誤検出が発生した。According to this graph, the broken line 40 indicates the end face 18
It can be seen that the S / N ratio decreases as the distance from a increases. Also, the solid line 41 represents the center 1 from the end face 18a.
The S / N ratio is almost constant up to 8d. According to this, it can be seen that the power density of the inspection light indicated by the solid line 41 is lower than that of the broken line 40 as a whole, but there is no shortage in practical use even at this power density level. Defects of size were correctly detected. On the other hand, in the case of the broken line 41, the inspection light near the end face 18a was too strong, and erroneous detection occurred.
【００２６】なお、Ｓ／Ｎ比をほぼ一定にするための収
束率の求め方としては、被検査物、例えばガラス板やプ
ラスチック板等によって検査光の減衰する割合が異なる
ため、予め被検査物に一定な検査光を入射して端面から
の距離に対するＳ／Ｎ比の減衰量を求めておく。そし
て、被検査物の両端面から検査光を入射する場合には、
中央部付近でのＳ／Ｎ比を基準に端面付近の検査光の幅
を決定する。また、片側端面のみから検査光を入射する
場合には、反対側端面付近のＳ／Ｎ比を基準に端面付近
の検査光の幅を決定する。また、レンズ群３２として
は、トーリックレンズを１個用いるようにしてもよい。The convergence rate for making the S / N ratio substantially constant is determined in advance because the rate of attenuation of the inspection light varies depending on the object to be inspected, for example, a glass plate or a plastic plate. , A constant inspection light is incident on the sample, and the attenuation of the S / N ratio with respect to the distance from the end surface is obtained. Then, when the inspection light enters from both end surfaces of the inspection object,
The width of the inspection light near the end face is determined based on the S / N ratio near the center. When the inspection light is incident only from one end face, the width of the inspection light near the end face is determined based on the S / N ratio near the opposite end face. Further, as the lens group 32, one toric lens may be used.
【００２７】次に上記検査装置の作用について説明す
る。ガラス板１８は、搬送ローラや搬送ベルト等に載置
されて矢印Ｘ方向に連続的に搬送される。投光ユニット
１９からは、レーザ発振器２５から放射されたレーザ光
が、反射ミラー２６，第１ビーム形状設定レンズ２８，
反射ミラー２７，第２ビーム形状設定レンズ２９，第３
ビーム形状設定レンズ３０，第１ビーム形状設定レンズ
３１を介して、ユニットボックス２４の開口２４ａから
ガラス板１８の端面１８ａに検査光３３が入射される。
また、投光ユニット２０からも同様に検査光３４がガラ
ス板１８の端面に入射される。Next, the operation of the above inspection apparatus will be described. The glass plate 18 is placed on a transport roller, a transport belt, or the like, and is continuously transported in the arrow X direction. From the light projecting unit 19, the laser light emitted from the laser oscillator 25 is reflected by the reflection mirror 26, the first beam shape setting lens 28,
Reflection mirror 27, second beam shape setting lens 29, third
Inspection light 33 is incident on the end face 18a of the glass plate 18 from the opening 24a of the unit box 24 via the beam shape setting lens 30 and the first beam shape setting lens 31.
In addition, the inspection light 34 similarly enters the end surface of the glass plate 18 from the light emitting unit 20.
【００２８】ガラス板１８の内部に入射される検査光３
３，３４は、ガラス板１８の厚み方向で図４に示すよう
に発散され、ガラス板１８の厚みと直交する方向では、
中央部１８ｄに向かって収束されていく。これにより、
検査光３３，３４はガラス板１８の内部を表裏面１８
ｂ，１８ｃで全反射を繰り返しながら進んでいくので、
厚み方向の検出感度が一定する。また、端面１８ａから
中央部１８ｄにかけての検査光３３，３４のパワー密度
がほぼ一定とされているので、誤検出は少ない。更に、
ガラス板１８の表裏面１８ｂ，１８ｃに付着した汚れや
ほこりに影響されることはない。Inspection light 3 incident inside glass plate 18
3, 34 are diverged in the thickness direction of the glass plate 18 as shown in FIG. 4, and in the direction orthogonal to the thickness of the glass plate 18,
It converges toward the central part 18d. This allows
The inspection lights 33 and 34 illuminate the inside of the glass plate 18 with the front and back surfaces 18.
As we proceed while repeating total reflection at b and 18c,
The detection sensitivity in the thickness direction is constant. Further, since the power densities of the inspection light beams 33 and 34 from the end face 18a to the central portion 18d are substantially constant, erroneous detection is small. Furthermore,
It is not affected by dirt or dust attached to the front and back surfaces 18b and 18c of the glass plate 18.
【００２９】検査光３３，３４は、ガラス板１８が搬送
されている間に入射されるので、ガラス板１８の全域に
おいて内部及び表裏面の欠陥を検出することができる。
そして、ガラス板１８の内部に欠陥３６があった場合に
は、検査光３３，３４が欠陥３６で散乱されて、ガラス
板１８の表裏面１８ｂ，１８ｃから放射される。この散
乱光は、ラインセンサカメラ２１によって光電検出さ
れ、検出信号が処理部２２に入力される。Since the inspection light beams 33 and 34 are incident while the glass plate 18 is being conveyed, it is possible to detect defects inside and on the front and back surfaces of the entire glass plate 18.
When the defect 36 exists inside the glass plate 18, the inspection lights 33 and 34 are scattered by the defect 36 and radiated from the front and back surfaces 18 b and 18 c of the glass plate 18. The scattered light is photoelectrically detected by the line sensor camera 21, and a detection signal is input to the processing unit 22.
【００３０】処理部２２では、検出信号が予め設定され
たスレッシュホールドレベルと比較される。検査光３
３，３４のパワー密度はほぼ一定とされているので、検
出信号のＳ／Ｎ比もほぼ一定となり、ガラス板１８の幅
方向の何処の位置の欠陥を検出した検出信号でも同一の
スレッシュホールドレベルと比較することができる。処
理部２２は、検出信号がこのスレッシュホールドレベル
を越えたときにガラス板１８内部に欠陥３６があると評
価し、表示パネル等に欠陥があることを表示するととも
に、欠陥のあるガラス板１８をライン上から取り除くよ
うに指示する。The processing unit 22 compares the detection signal with a preset threshold level. Inspection light 3
Since the power densities of the signals 3 and 34 are substantially constant, the S / N ratio of the detection signal is also substantially constant, and the same threshold level is used for the detection signal which detects a defect at any position in the width direction of the glass plate 18. Can be compared to When the detection signal exceeds the threshold level, the processing unit 22 evaluates that there is a defect 36 inside the glass plate 18, displays that the display panel or the like has a defect, and removes the defective glass plate 18. Tell them to remove them from the line.
【００３１】なお、上記各実施例の検査装置ではライン
センサを用いたが、代わりにエリアセンサを用いてもよ
い。また、ガラス板を固定して投光ユニットとラインセ
ンサとを移動させるようにしてもよい。更に、投光ユニ
ットを縦に配置し、検査光を反射ミラーで反射させてガ
ラス板に入射するようにしてもよい。また、ガラス板の
検査について説明したが、透明なプラスチック板等の検
査に用いてもよく、その他の透明な板状の検査物を表裏
面に付着した汚れやほこりの影響を受けずに検査する場
合に用いることができる。Although the line sensors are used in the inspection apparatuses of the above embodiments, an area sensor may be used instead. Further, the light projection unit and the line sensor may be moved with the glass plate fixed. Further, the light projecting unit may be arranged vertically, and the inspection light may be reflected by the reflection mirror and incident on the glass plate. In addition, although the inspection of the glass plate has been described, the inspection may be performed on a transparent plastic plate or the like, and other transparent plate-like inspection objects may be inspected without being affected by dirt or dust attached to the front and back surfaces. Can be used in some cases.
【００３２】以上説明したように、本発明の透明体の欠
陥検出方法は、表裏面を平滑にした板状の透明体を連続
走行させ、その幅方向の両端面から検査光を入射し、こ
の検査光が透明体の表裏面で全反射を繰り返しながら透
明体内部を伝播する過程で、透明体に存在する欠陥部に
よって散乱された散乱光を透明体の表裏いずれかの面を
通して光電検出するようにしたので、透明体の表裏面に
付着した汚れやほこりの影響を受けずに、内部及び表裏
面の欠陥を正確に検出することができる。As described above, in the method for detecting a defect in a transparent body according to the present invention, a plate-shaped transparent body having a smooth front and back surface is continuously run, and inspection light is incident from both end surfaces in the width direction. In the process of inspection light propagating inside the transparent body while repeating total reflection on the front and back surfaces of the transparent body, scattered light scattered by a defect existing in the transparent body is photoelectrically detected through one of the front and back surfaces of the transparent body Therefore, the inside and the front and back surface defects can be accurately detected without being affected by dirt and dust attached to the front and back surfaces of the transparent body.
【００３３】また、透明体の欠陥検出装置は、検査光と
してレーザ光を用い、このレーザ光を透明体の厚み方向
で発散するように入射させたので、厚み方向の検出感度
のバラツキが軽減できる。また、レーザ光の透明体の厚
みと直交する方向では、レーザビームを収束させて入射
するようにしたので、全域において検査光の強度がほぼ
一定となり誤検出が減少するとともに、検出信号の処理
が容易になる。また、装置を小型化できコストも低減で
きる。Further, the apparatus for detecting a defect in a transparent body uses laser light as inspection light and irradiates the laser light so as to diverge in the thickness direction of the transparent body, so that variations in detection sensitivity in the thickness direction can be reduced. . Also, in the direction perpendicular to the thickness of the transparent body of the laser beam, the laser beam is converged and incident, so that the intensity of the inspection light is almost constant over the entire area, erroneous detection is reduced, and processing of the detection signal is reduced. It will be easier. Further, the size of the apparatus can be reduced and the cost can be reduced.
【図１】本発明の透明体の欠陥検出装置の構成を示す概
略図である。FIG. 1 is a schematic view showing a configuration of a transparent body defect detection device of the present invention.
【図２】検査光による欠陥の検出状態を示すガラス板の
側面図である。FIG. 2 is a side view of a glass plate showing a state of detection of a defect by inspection light.
【図３】本発明の別の実施例の透明体の欠陥検出装置の
構成を示す概略図である。FIG. 3 is a schematic diagram showing a configuration of a transparent body defect detection apparatus according to another embodiment of the present invention.
【図４】別の実施例の検査光による欠陥の検出状態を示
すガラス板の側面図である。FIG. 4 is a side view of a glass plate showing a state of detecting a defect by inspection light according to another embodiment.
【図５】ガラス板搬送方向の検査光の収束状態を示す説
明図である。FIG. 5 is an explanatory diagram showing a convergence state of inspection light in a glass plate conveyance direction.
【図６】ガラス板端面からの距離における検出信号のＳ
／Ｎ比を表すグラフである。FIG. 6 shows S of the detection signal at a distance from the end surface of the glass plate.
4 is a graph showing the / N ratio.
【符号の説明】 ２，１９，２０ 投光ユニット ３，２１ ラインセンサカメラ ４，２２ 処理部 ５，１８ ガラス板 １３，３３，３４ 検査光[Description of Signs] 2,19,20 Projection Unit 3,21 Line Sensor Camera 4,22 Processing Unit 5,18 Glass Plate 13,33,34 Inspection Light
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭61−284648（ＪＰ，Ａ) 特開 昭63−165738（ＪＰ，Ａ) 特開 平７−72092（ＪＰ，Ａ) 特開 昭56−17014（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G01N 21/84 - 21/958 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-284648 (JP, A) JP-A-63-165738 (JP, A) JP-A-7-72092 (JP, A) JP-A Sho 56-284 17014 (JP, A) (58) Field surveyed (Int. Cl. 7 , DB name) G01N 21/84-21/958
Claims (1)
走行させ、この透明体の幅方向の両端面から、該透明体
の表裏面で全反射を繰り返しながら他方の端面に向かう
検査レーザ光を入射する投光器と、検査レーザ光の入射
方向に沿った検査視野をもち、透明体の表裏いずれかの
面を通して透明体内部で散乱した散乱光を光電検出する
受光器と、この受光器からの出力に基づいて透明体に存
在する欠陥を識別する処理手段とを備えた透明体の欠陥
検出装置において、 前記投光器は、検査レーザ光を透明体の厚み方向で発散
させ、該透明体の厚みと直交する方向では幅方向の中央
部近傍で収束させることを特徴とする透明体の欠陥検出
装置。 1. A front and rear surfaces is continuously run smooth in the plate-shaped transparent body, from both end faces in the width direction of the transparent body, toward the other end surface while repeating total reflection at the front and back surfaces of the transparent body
Projector for entering inspection laser beam and incidence of inspection laser beam
The inspection field of view along the direction
Photoelectrically detects the scattered light scattered inside the transparent body through the surface
A receiver and a transparent object based on the output from the receiver.
Processing means for identifying existing defects
In the detection device, the projector emits the inspection laser light in a thickness direction of the transparent body.
And in the direction perpendicular to the thickness of the transparent body, the center in the width direction.
Defect detection of transparent material characterized by converging near the part
apparatus.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7066205A JP3036733B2 (en) | 1995-03-24 | 1995-03-24 | Defect detection device for transparent objects |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7066205A JP3036733B2 (en) | 1995-03-24 | 1995-03-24 | Defect detection device for transparent objects |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08261953A JPH08261953A (en) | 1996-10-11 |
| JP3036733B2 true JP3036733B2 (en) | 2000-04-24 |
Family
ID=13309110
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7066205A Expired - Fee Related JP3036733B2 (en) | 1995-03-24 | 1995-03-24 | Defect detection device for transparent objects |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3036733B2 (en) |
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| DE69833580T2 (en) * | 1997-07-17 | 2006-12-07 | Hoya Corp. | Device for inspecting a transparent material with regard to irregularities |
| US6392683B1 (en) * | 1997-09-26 | 2002-05-21 | Sumitomo Heavy Industries, Ltd. | Method for making marks in a transparent material by using a laser |
| JP3673631B2 (en) * | 1997-12-26 | 2005-07-20 | Ｈｏｙａ株式会社 | Non-uniformity inspection method and apparatus for translucent material |
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1995
- 1995-03-24 JP JP7066205A patent/JP3036733B2/en not_active Expired - Fee Related
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