JP3369268B2 - Defect detection method inside translucent object - Google Patents
Defect detection method inside translucent objectInfo
- Publication number
- JP3369268B2 JP3369268B2 JP24827593A JP24827593A JP3369268B2 JP 3369268 B2 JP3369268 B2 JP 3369268B2 JP 24827593 A JP24827593 A JP 24827593A JP 24827593 A JP24827593 A JP 24827593A JP 3369268 B2 JP3369268 B2 JP 3369268B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- defect
- scattering
- transparent object
- detection
- 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
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
- G01N21/958—Inspecting transparent materials or objects, e.g. windscreens
Description
【０００１】[0001]
【産業上の利用分野】本発明は、透光性物体内部の欠点
検出方法に関し、特に表裏面が光散乱面である透光性物
体の内部の欠点の検出方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting defects inside a transparent object, and more particularly to a method for detecting defects inside a transparent object whose front and back surfaces are light scattering surfaces.
【０００２】[0002]
【従来の技術】従来、表裏面が光散乱面である透光性物
体内部の欠点を検出する場合、透光性物体表面での光の
散乱による影響を除去するために、検査対象である透光
性物体を該物体と等屈折率の液体に浸したり、等屈折率
の液体を塗ったりする方法が採用されていた。2. Description of the Related Art Conventionally, when a defect inside a light-transmissive object whose front and back surfaces are light-scattering surfaces is detected, in order to eliminate the influence of light scattering on the surface of the light-transmissive object, the light-transmission object to be inspected is to be inspected. A method of immersing an optical object in a liquid having the same refractive index as that of the object or coating a liquid having the same refractive index has been adopted.
【０００３】[0003]
【発明が解決しようとする課題】しかしこのような方法
では、等屈折率の液体を塗る工程等において該液体中に
泡が発生することがあり、該泡が誤検出の原因となると
いう問題がある。さらに、等屈折率の液体を塗ったり、
乾かしたりの余計な工程が入る上、等屈折率の液体との
接触により検査対象である透光性物体の特性が変わるお
それがあるなどの問題がある。However, in such a method, there is a problem that bubbles may be generated in the liquid in the step of applying a liquid having an equal refractive index, and the bubbles may cause erroneous detection. is there. In addition, apply a liquid of equal refractive index,
There are problems that an extra step such as drying is required, and that the characteristics of the translucent object to be inspected may change due to contact with a liquid having an equal refractive index.
【０００４】また、欠点からの散乱光のうち、透光性物
体内部を反射等により伝播し、端面より出射してくる光
を受光素子等を用いて検出する方法（特開昭６４−５７
１５４号、特開平５−７９９９４号）を、表裏面が光散
乱面である透光性物体の内部の欠点の検出に利用する場
合、光ビームが直接当たった部分、および欠点部分から
受光素子までのみちすじに相当する部分にある光散乱面
である透光性物体表面の面性状により検出光量が大きく
ばらつく。特に透光性物体表面の光散乱状態のばらつき
が大きい場合には、微細な欠点の検出は困難である。ま
た、透光性物体端面が光散乱面であるような場合には、
欠点の検出はきわめて難しい。Further, of scattered light from the defect, a light propagating inside the light-transmitting object by reflection or the like and emitting from the end face is detected by using a light receiving element or the like (Japanese Patent Laid-Open No. 64-57).
No. 154, JP-A-5-79994) for detecting defects inside a light-transmissive object whose front and back surfaces are light-scattering surfaces, from the part directly hit by the light beam and from the defect part to the light receiving element. The amount of detected light greatly varies depending on the surface texture of the light-transmitting object surface, which is the light-scattering surface in the portion corresponding to the stripe. In particular, when the light scattering state on the surface of the transparent object is large, it is difficult to detect minute defects. Also, when the end surface of the transparent object is a light scattering surface,
Defect detection is extremely difficult.
【０００５】[0005]
【課題を解決するための手段】本発明は前述の課題を解
決すべくなされたものであり、表裏面が光散乱面である
透光性物体の内部の欠点の検出方法であって、光ビーム
光源を用いて、光ビームを透光性物体表面より入射させ
て透光性物体表面に散乱光源をつくり、該透光性物体の
端面を通して前記欠点に検出光学系の焦点を合わせ、受
光素子を用いて、該散乱光源よりの光の反射、散乱によ
り欠点を輝点として検出することを特徴とする透光性物
体内部の欠点検出方法を提供する。The present invention has been made to solve the above-mentioned problems, and is a method for detecting a defect inside a light-transmissive object whose front and back surfaces are light-scattering surfaces. using <br/> light source is incident light beam from the light transmitting surface of an object
To form a scattering light source on the surface of the transparent object, focus the detection optical system on the defect through the end face of the transparent object , and receive it.
An optical element is used to reflect and scatter light from the scattering light source.
Ri provides detected to translucent objects inside the fault detection method is characterized in Rukoto as bright point defect.
【０００６】[0006]
【作用】本発明においては、表裏面が光散乱面である透
光性物体の内部の欠点の検出をする際、光散乱面である
表面または裏面より光ビームを入射させ、透光性物体表
面等に散乱光源をつくり欠点における反射、散乱による
輝点を受光素子を有する光学系等を用いて、透光性物体
端面を通して前記輝点に検出の焦点を合わせて検出を行
っているので、等屈折率液体などを使う必要なく非接触
で確実で簡易な透光性物体内部の欠点検査が可能とな
る。透光性物体端面が光散乱面であっても、一般に表面
または裏面の光散乱面よりも端面の光散乱面の方が欠点
から遠いため、結像系のアウトフォーカス効果により、
光散乱面の影響を小さく抑えることができる。According to the present invention, when the front and back surfaces to the detection of internal defects of the light-transmitting object is a light scattering surface, is incident surface or back surface by Rihikari beam is a light scattering surface, translucent Since a scattered light source is created on the object surface, etc., the luminescent spot due to reflection and scattering in the defect is detected by focusing on the luminescent spot through the transparent object end face by using an optical system having a light receiving element. , It is possible to perform a non-contact, reliable and simple defect inspection in a transparent object without using a liquid having an equal refractive index. Even if the end surface of the transparent object is a light scattering surface, the light scattering surface of the end surface is generally farther from the defect than the light scattering surface of the front surface or the back surface.
The influence of the light scattering surface can be suppressed to be small.
【０００７】また、この方法は透光性物体の表裏面が光
散乱面である場合のみならず、例えば表裏面が汚れや凹
凸等を伴い検出の障害となるような場合についても有用
である。また、検出した欠点の位置情報より、表面の欠
点、汚れ等と透光性物体内部の欠点を容易に確実に識別
することが可能となる。Further, this method is useful not only when the front and back surfaces of the light-transmissive object are light scattering surfaces, but also when the front and back surfaces are contaminated due to dirt, unevenness, etc. Further, it is possible to easily and surely identify the surface defect, stain, etc. and the defect inside the transparent object from the position information of the detected defect.
【０００８】[0008]
【実施例】以下に本発明を実施例を用いて説明する。図
１は本発明の実施例の斜視図であり、１は例えばカメラ
のような受光素子である。該受光素子は場合によっては
複数台を設ける。２は検査対象である透光性物体であ
り、３は検出に用いる端面、４は光散乱面である。レー
ザー光源６よりのレーザー光７をポリゴンミラーまたは
ガルバノミラー等の走査装置５を用いて、照射場所を線
状に限定した光ビームを作成した。該光ビームはファイ
バ、マスク光源等を用いて作成してもよい。８は検出器
より得られた信号を処理、判定する信号処理手段であ
る。本実施例において、必ずしもレーザー光を走査する
などして線状に照射することを要せず、例えばレーザー
光を点状に照射し検査対象である透光性物体を縦横に走
査することによっても同様の効果が得られる。EXAMPLES The present invention will be described below with reference to examples. FIG. 1 is a perspective view of an embodiment of the present invention, and 1 is a light receiving element such as a camera. A plurality of light receiving elements are provided depending on the case. Reference numeral 2 is a transparent object to be inspected, 3 is an end surface used for detection, and 4 is a light scattering surface. A laser beam 7 from a laser light source 6 was used to form a light beam in which the irradiation location was limited to a linear shape by using a scanning device 5 such as a polygon mirror or a galvano mirror. The light beam may be created using a fiber, a mask light source, or the like. Reference numeral 8 is a signal processing means for processing and judging the signal obtained from the detector. In the present embodiment, it is not always necessary to irradiate linearly by scanning the laser light, for example, by irradiating the laser light in spots and scanning the transparent object to be inspected vertically and horizontally. The same effect can be obtained.
【０００９】図２は、図１に示される実施例における欠
点検出の概要を示す断面図である。光散乱面４に照射さ
れたレーザー光７は光散乱面４上の走査線９において散
乱光源となる。検出に用いる端面３と平行な走査線９を
含む面に検出光学系の受光素子１の焦点が合わされてお
り、前記面上に例えば気泡などの欠点１０があれば散乱
光は反射、散乱されて輝点となり受光素子１で検出され
る。検査対象である透光性物体２を矢印の方向に走査す
ることにより透光性物体２の全面の検査が可能となる。FIG. 2 is a sectional view showing an outline of defect detection in the embodiment shown in FIG. The laser light 7 applied to the light scattering surface 4 becomes a scattering light source at the scanning line 9 on the light scattering surface 4. The light receiving element 1 of the detection optical system is focused on a surface including a scanning line 9 parallel to the end surface 3 used for detection, and if there is a defect 10 such as a bubble on the surface, scattered light is reflected and scattered. It becomes a bright spot and is detected by the light receiving element 1. The entire surface of the transparent object 2 can be inspected by scanning the transparent object 2 to be inspected in the direction of the arrow.
【００１０】本実施例において、透光性物体表面のレー
ザー光７の走査線９を含む面に検出光学系の焦点を合わ
せ、透光性物体２を走査するため、レーザー光７の走査
位置、すなわち線状に走査したレーザー光が当っている
透光性物体２の断面に欠点があると特定でき、さらに受
光素子１内における輝点の検出される位置より、欠点が
透光性物体２内のどこにあるかを三次元的に知ることが
できる。In this embodiment, the laser on the surface of the transparent object is
The detection optical system is focused on the surface including the scanning line 9 of the laser light 7.
Since the transparent object 2 is scanned, it can be specified that there is a defect in the scanning position of the laser light 7, that is, the cross section of the transparent object 2 on which the linearly scanned laser light hits. It is possible to three-dimensionally know where the defect is in the translucent object 2 from the position where the bright spot is detected.
【００１１】本実施例において、透光性物体２の検出に
用いる端面３が鏡面となっていれば最もよいが、検出に
用いる端面３がたとえ光散乱面であっても、欠点である
輝点と光散乱面である検出に用いる端面３との距離が大
きいため、光散乱面である検出に用いる端面３がアウト
フォーカスの位置となり検出への影響は小さい。本実施
例では、正方形で１５０ｍｍ角、厚さ３ｍｍのガラス板
であって、表裏面および端面が光散乱面である透光性物
体２の欠点検出を行った。ガラス板内の直径０．２ｍｍ
程度の気泡について、二次元ＣＣＤカメラを用いて、ｆ
７０、Ｆ１１の光学系でＳ／Ｎが３以上の感度で検出で
きた。In this embodiment, it is best if the end face 3 used for detecting the translucent object 2 is a mirror surface. However, even if the end face 3 used for detection is a light scattering surface, there is a defect of bright spots. Since the distance between the end surface 3 which is a light scattering surface and used for detection is large, the end surface 3 which is a light scattering surface and used for detection is at the out-of-focus position and the influence on detection is small. In this example, a defect was detected for a transparent object 2 which is a square glass plate 150 mm square and 3 mm thick and whose front and back surfaces and end surfaces are light scattering surfaces. Diameter 0.2 mm in glass plate
For a bubble of a certain degree, using a two-dimensional CCD camera, f
The optical system of 70 and F11 could detect S / N with a sensitivity of 3 or more.
【００１２】また、図３に示される別の実施例のよう
に、レーザー光７を検出方向と平行な方向に線状に走査
し、それと同期させて焦点合わせをし、検出されたタイ
ミングにより欠点の位置を求めても同じ効果が得られ
る。Further, as another embodiment shown in FIG. 3, is scanned linearly in the direction parallel to the direction detect the laser beam 7, therewith to focusing in synchronization, the detected timing The same effect can be obtained by obtaining the position of the defect.
【００１３】本発明は、表裏面が光散乱面である板状の
透光性物体内部の欠点検出に用いて好適であるが、透光
性物体は板状体に限定されるものではなく他の形状であ
っても適用できる。The present invention is suitable for use in detecting defects inside a plate-shaped transparent object having front and back surfaces as light scattering surfaces, but the transparent object is not limited to a plate-shaped object. It can be applied even in the shape of.
【００１４】[0014]
【発明の効果】本発明により、等屈折率液体等を用いる
ことなく、簡易に安定的に表裏面が光散乱面である透光
性物体内部の欠点の検出、検査が可能となる。それによ
り、検査の信頼性の向上、工程の簡略化を達成できる。According to the present invention, it is possible to easily and stably detect and inspect defects inside a light-transmissive object whose front and back surfaces are light-scattering surfaces, without using a liquid having a constant refractive index. As a result, the reliability of the inspection can be improved and the process can be simplified.
【図１】本発明の実施例を説明する斜視図。FIG. 1 is a perspective view illustrating an embodiment of the present invention.
【図２】図１に示す実施例の断面図。FIG. 2 is a sectional view of the embodiment shown in FIG.
【図３】本発明の別の実施例を説明する斜視図。 FIG. 3 is a perspective view illustrating another embodiment of the present invention .
１：受光素子 ２：透光性物体 ３：検出に用いる端面 ４：光散乱面 ５：走査手段 ６：レーザー光源 ７：レーザー光 ８：信号処理手段 ９：走査線 １０：欠点 1: Light receiving element 2: Translucent object 3: End face used for detection 4: Light scattering surface 5: scanning means 6: Laser light source 7: Laser light 8: Signal processing means 9: Scan line 10: Drawback
Claims (2)
の欠点の検出方法であって、光ビーム光源を用いて、光
ビームを透光性物体表面より入射させて透光性物体表面
に散乱光源をつくり、該透光性物体の端面を通して前記
欠点に検出光学系の焦点を合わせ、受光素子を用いて、
該散乱光源よりの光の反射、散乱により欠点を輝点とし
て検出することを特徴とする透光性物体内部の欠点検出
方法。1. A front and back surfaces is a method for detecting internal defect of the light-transmitting object is a light scattering surface, using a light beam light source, the light
The beam is made incident on the surface of the transparent object so that the surface of the transparent object is exposed.
A scattering light source is formed in , the detection optical system is focused on the defect through the end face of the transparent object , and a light receiving element is used.
A defect is a bright spot due to reflection and scattering of light from the scattering light source.
Translucent object inside the fault detection method is characterized that you detect Te.
含む面に前記検出光学系の焦点を合わせ、透光性物体を
走査させることにより、欠点の位置情報を得る請求項１
に記載の透光性物体内部の欠点検出方法。2. The scanning line of the light beam on the surface of the transparent object is
Focus the transmissive object by focusing the detection optical system on the surface containing
The defect position information is obtained by scanning.
A method for detecting a defect inside a transparent object according to.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24827593A JP3369268B2 (en) | 1993-10-04 | 1993-10-04 | Defect detection method inside translucent object |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24827593A JP3369268B2 (en) | 1993-10-04 | 1993-10-04 | Defect detection method inside translucent object |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07103904A JPH07103904A (en) | 1995-04-21 |
| JP3369268B2 true JP3369268B2 (en) | 2003-01-20 |
Family
ID=17175699
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24827593A Expired - Fee Related JP3369268B2 (en) | 1993-10-04 | 1993-10-04 | Defect detection method inside translucent object |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3369268B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10261323B3 (en) * | 2002-12-27 | 2004-10-07 | Infineon Technologies Ag | Device and method for determining structural and / or geometric properties of a mask blank |
| JP2017032523A (en) * | 2015-08-06 | 2017-02-09 | 株式会社オハラ | Optical glass base material defect inspection device and optical glass base material defect inspection method |
-
1993
- 1993-10-04 JP JP24827593A patent/JP3369268B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07103904A (en) | 1995-04-21 |
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