JPH0551845B2 - - Google Patents
Info
- Publication number
- JPH0551845B2 JPH0551845B2 JP58026671A JP2667183A JPH0551845B2 JP H0551845 B2 JPH0551845 B2 JP H0551845B2 JP 58026671 A JP58026671 A JP 58026671A JP 2667183 A JP2667183 A JP 2667183A JP H0551845 B2 JPH0551845 B2 JP H0551845B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- inspected
- light receiving
- reflected light
- enlarged image
- 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 - Lifetime
Links
- 230000001427 coherent effect Effects 0.000 claims description 10
- 230000003287 optical effect Effects 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 8
- 238000007689 inspection Methods 0.000 claims description 7
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000011179 visual inspection Methods 0.000 description 1
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
Description
【発明の詳細な説明】
この発明は外側に凸な曲面を有する円形物の外
観検査方法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for inspecting the appearance of a circular object having an outwardly convex curved surface.
従来、工作機械などで作られた製品の外観検査
は、曲率のある仕上げ面に白色光を照射し、その
反射光による投影像を拡大して受光部で判別する
ことにより行われていた。 Conventionally, the appearance inspection of products made with machine tools and the like has been carried out by shining white light onto a curved finished surface, magnifying the projected image of the reflected light, and using a light-receiving section to identify the image.
しかし、上記検査方法では、白色光は外光によ
つて強い影響を受けるため微小傷の検出が容易で
ない上に、投影像の拡大に結像レンズ等の光学系
を必要とするため、光学系が強い制約を受けると
ともに、受光部の選択が困難になる不都合があつ
た。 However, with the above inspection method, it is not easy to detect minute scratches because white light is strongly affected by external light, and an optical system such as an imaging lens is required to magnify the projected image. This has the disadvantage of being subject to strong restrictions and making it difficult to select a light-receiving section.
この発明は上記不都合を解消したもので、外側
に凸な曲面を有する円形物の外観検査方法の提供
を目的とする。 The present invention solves the above-mentioned disadvantages and aims to provide a method for inspecting the appearance of a circular object having an outwardly convex curved surface.
この発明の方法を図面について説明すれば、外
側に凸な曲面を有する円形物（以下被検査物と略
記する）１に、レーザーヘツド２から、例えば
He−Neレーザー（6328Å）のようなコヒーレン
ト光３を照射し、その反射光４による明暗な拡大
像を直接受光部５に投影して被検出部１の表面の
微小傷を、光学系を用いて拡大することなく高精
度に判別することを特徴とするものである。な
お、本発明は、幾何光学の領域に属するものであ
る。 The method of the present invention will be explained with reference to the drawings.
A coherent light 3 such as a He-Ne laser (6328 Å) is irradiated, and a bright and dark enlarged image of the reflected light 4 is directly projected onto the light receiving part 5 to detect minute scratches on the surface of the detected part 1 using an optical system. It is characterized by highly accurate discrimination without enlarging the image. Note that the present invention belongs to the field of geometric optics.
この発明の方法の一実施例を第１図ないし第３
図について説明する。レーザーヘツド２から平行
なコヒーレント光３をベアリングローラのような
外側に凸な曲面を有する被検査物１の外表面に照
射すれば、反射光４は外表面への入射点における
法線Ｎに対して反射角θ2が入射角θ1と等しくなる
方向に反射されるため、反射面上の表面状態は幾
何光学的に拡大される。外表面に微少傷がある場
合、その部分における反射光４の方法は、微小傷
がない場合と比べて反射の方向を異にするから、
受光部５における拡大像には、明暗のパターンを
生ずる。 An embodiment of the method of this invention is shown in FIGS. 1 to 3.
The diagram will be explained. When parallel coherent light 3 is irradiated from a laser head 2 onto the outer surface of an object to be inspected 1 having an outwardly convex curved surface, such as a bearing roller, the reflected light 4 will be reflected with respect to the normal N at the point of incidence on the outer surface. Since the reflected light is reflected in a direction in which the reflection angle θ 2 is equal to the incidence angle θ 1 , the surface condition on the reflecting surface is expanded geometrically. If there is a minute scratch on the outer surface, the direction of the reflected light 4 at that part will be different compared to when there is no minute scratch.
The enlarged image in the light receiving section 5 produces a bright and dark pattern.
反射光４を干渉フイルター６に通して直接受光
部５に投影させれば、所望の波長を中心として狭
少波長域の反射光４だけが干渉フイルター６を通
過するので検査部に外光の外乱があつても、その
影響を著しく少なくすることができる。この反射
光４を集光レンズ７により受光部５に投影し、該
受光部５を構成する受光素子８を用いて電気信号
に変換したのち、同電気信号の電圧の高低で外表
面の微小傷に基づく明暗のパターンを読み取ら
せ、その読み取り結果を受光部５に接続した電子
回路９で判別して被検査物１の外観検査を行う。
この場合、被検査物１を軸線Ｘ（紙面に垂直）の
回りに矢印ａで示す方向へ連続的に回転させれ
ば、コヒーレント光３が照射されている領域につ
いて被検査物１の表面全体の外観検査を自動的に
行うことができる。 If the reflected light 4 is passed through the interference filter 6 and projected directly onto the light receiving section 5, only the reflected light 4 in a narrow wavelength range centered around the desired wavelength will pass through the interference filter 6, so that the inspection section will not be disturbed by external light. Even if there is, the impact can be significantly reduced. This reflected light 4 is projected onto a light receiving section 5 by a condensing lens 7, and converted into an electrical signal using a light receiving element 8 constituting the light receiving section 5.Then, microscopic scratches on the outer surface are caused by the voltage level of the electrical signal. The appearance of the object 1 to be inspected is inspected by reading a pattern of brightness and darkness based on , and determining the read result by an electronic circuit 9 connected to the light receiving section 5 .
In this case, if the inspected object 1 is continuously rotated around the axis X (perpendicular to the page) in the direction indicated by arrow a, the entire surface of the inspected object 1 can be Appearance inspection can be performed automatically.
上記外観検査において、反射光４による拡大像
の倍率は、第２図に示すように、反斜面の曲率半
径ｒ、その曲率中心から観測位置Ｐまでの距離
をＲとすれば、Ｒ／ｒで表わされる。その上、コ
ヒーレント光３は空間的コヒーレンスが従来の白
色光に比して格段に良く外光による影響が少ない
ため、反斜面上の表面状態と拡大像とは、任意の
観測位置でも１対１に対応しているから、観測位
置Ｐの選定は、R2に反比例して減衰する反射光
４の強度とその影響を受ける受光素子８の感度に
よつて制限を受けるとはいえ、コヒーレント光３
の高輝度、高エネルギー密度性によつて、光学系
手段で倍率をあげることなく、十分に実用できる
倍率の採用を可能ならしめる。このことは、光学
系手段の構成を簡単にするだけでなく、従来観測
位置Ｐで必要としていた光電子増幅管およびそれ
に付属する高圧回路をも不必要とするため、受光
系の構成をも著しく簡単にする。また、光学素子
８としてSi−フオト・ダイオード等を用いるだけ
で、十分に拡大された像の明暗パターンを検出で
き、受光部５に接続されるソリツドステートな電
子回路９とのマツチングを容易にする。なお、同
一倍率下の観測でも分解能を向上したいときに
は、受光素子８をソリツドステート化し、単位受
光素子１０を第３図ｂ，ｃに示すように、アレー
状またはマトリツクス状に配列すればよい。 In the above visual inspection, the magnification of the enlarged image by reflected light 4 is R/r, as shown in Figure 2, where r is the radius of curvature of the opposite slope and R is the distance from the center of curvature to observation position P. expressed. Furthermore, coherent light 3 has much better spatial coherence than conventional white light and is less affected by external light, so the surface state on the opposite slope and the magnified image are 1:1 even at any observation position. Therefore, the selection of the observation position P is limited by the intensity of the reflected light 4, which is attenuated in inverse proportion to R2 , and the sensitivity of the light receiving element 8, which is affected by it.
Due to its high brightness and high energy density, it is possible to use a sufficiently practical magnification without increasing the magnification using optical means. This not only simplifies the configuration of the optical system means, but also eliminates the need for a photoelectron amplifier tube and its attached high-voltage circuit, which were conventionally required at the observation position P, and therefore significantly simplifies the configuration of the light receiving system. Make it. Furthermore, by simply using a Si-photo diode or the like as the optical element 8, the light and dark pattern of a sufficiently enlarged image can be detected, and matching with the solid-state electronic circuit 9 connected to the light receiving section 5 can be easily performed. do. If it is desired to improve the resolution even when observing at the same magnification, the light-receiving elements 8 may be made into a solid state, and the unit light-receiving elements 10 may be arranged in an array or matrix as shown in FIGS. 3b and 3c.
以上詳述したように、本発明によれば、照射光
として空間的コヒーレンスが良く、高輝度で単色
性に優れるコヒーレント光を用いたから、以下に
列挙するような種々のすぐれた効果が得られる。 As detailed above, according to the present invention, since coherent light having good spatial coherence, high brightness, and excellent monochromaticity is used as irradiation light, various excellent effects as listed below can be obtained.
(1) コヒーレント光の空間的コヒーレンスの良さ
により、被検査物の凸表面（検査面）の状態
を、レンズ等の光学系手段を用いることなく、
高精度で検査することができる。(1) Due to the good spatial coherence of coherent light, the condition of the convex surface (inspection surface) of the object to be inspected can be detected without using optical system means such as lenses.
Can be inspected with high precision.
すなわち、曲率のある金属面にコヒーレント
光を照射した場合、空間的コヒーレンスの良さ
により、この照射表面の状態（パターン）は反
射光によつて幾何学的に拡大され、しかも任意
の観測位置の反射光による拡大像は、上記照射
表面の状態と１対１に対応することとなる。 In other words, when a metal surface with curvature is irradiated with coherent light, the state (pattern) of the irradiated surface is geometrically expanded by the reflected light due to the good spatial coherence, and the reflection at any observation position is The enlarged image by light corresponds one-to-one to the state of the irradiated surface.
したがつて、任意の観測点を選ぶことによつ
て、上記照射表面の微小傷を含めた表面状態
を、レンズ等の光学系を用いなくても、任意の
倍率で十分に拡大して精度良く観測することが
できる。 Therefore, by selecting an arbitrary observation point, the surface condition of the irradiated surface, including minute scratches, can be sufficiently magnified at any magnification and accurately without using an optical system such as a lens. It can be observed.
(2) コヒーレント光の光輝度性により、観測位置
における光電子増幅管とそれに付属する高圧回
路の省略を可能にして、受光素子の選択を容易
にする。このため、上記空間的コヒーレンスの
良さと相まつて、光学系手段に対する制約が大
幅に緩和されるとともに、受光部の構成も簡単
にすることができる。(2) The brightness of coherent light makes it possible to omit a photoelectron amplifier tube and its attached high-voltage circuit at the observation position, making it easier to select a photodetector. Therefore, in combination with the above-mentioned good spatial coherence, restrictions on the optical system means are significantly relaxed, and the configuration of the light receiving section can be simplified.
(3) コヒーレント光の単色性は、従来用いられて
いた白色光に比して格段にすぐれるため、外光
による外乱の影響は少なくして、検査精度の安
定性を高めることができる。(3) Since the monochromaticity of coherent light is much superior to that of conventionally used white light, it is possible to reduce the influence of external light disturbance and improve the stability of inspection accuracy.
(4) 反射光を干渉フイルターに通して受光部に投
影させるから、所望の波長を中心として狭小波
長域の反射光だけが干渉フイルターを通過する
こととなり、このため、受光部ならびに検査部
に外光の外乱があつても、その影響を従来に比
して著しく少なくすることができる。(4) Since the reflected light passes through the interference filter and is projected onto the light receiving section, only the reflected light in a narrow wavelength range centered around the desired wavelength passes through the interference filter. Even if there is a disturbance of light, its influence can be significantly reduced compared to the conventional method.
第１図はこの発明の一実施例を示す正面図、第
２図は投影像の倍率を説明する断面図、第３図は
受光素子のそれぞれ異なる配列を示す正面図であ
る。
１……被検査物（円形物）、３……コヒーレン
ト光（レーザー光）、４……反射光、５……受光
部、６……干渉フイルター、８……受光素子、９
……電子回路、Ｘ……軸線。
FIG. 1 is a front view showing an embodiment of the present invention, FIG. 2 is a sectional view illustrating the magnification of a projected image, and FIG. 3 is a front view showing different arrangements of light receiving elements. 1... Object to be inspected (circular object), 3... Coherent light (laser light), 4... Reflected light, 5... Light receiving section, 6... Interference filter, 8... Light receiving element, 9
...electronic circuit, X...axis line.
Claims (1)
物の凸表面に対して、レーザヘツドから平行なコ
ヒーレント光を照射して、 その反射光のうちの正反射光の光路に設けた干
渉フイルターで所望波長の光を取り出し、 この所望波長の光による照射表面の前記正反射
光による拡大像を、受光素子からなる受光部に直
接投影し、 前記受光素子により、前記拡大像を電気信号に
変換して、その電気信号に基づいて前記拡大像の
明暗のパターンを読み取り、 この読み取り結果に基づいて前記照射表面の微
小傷の有無を判定するようにした円形物の外観検
査方法。 ２ 前記被検査物をその軸線の回りに回転させ
て、前記被検査物の表面を連続的に検査する特許
請求の範囲第１項記載の円形物の外観検査方法。[Scope of Claims] 1. A laser head that irradiates parallel coherent light onto a convex surface of an object to be inspected that has a smooth finished surface with curvature, and places it in the optical path of specularly reflected light of the reflected light. extracting light of a desired wavelength with an interference filter, projecting an enlarged image of the specularly reflected light of the surface irradiated with the light of the desired wavelength directly onto a light receiving section consisting of a light receiving element, and transmitting the enlarged image electrically by the light receiving element; A method for inspecting the appearance of a circular object, the method comprising converting the electrical signal into a signal, reading the light and dark pattern of the enlarged image based on the electrical signal, and determining the presence or absence of minute scratches on the irradiated surface based on the reading result. 2. The external appearance inspection method for a circular object according to claim 1, wherein the surface of the object to be inspected is continuously inspected by rotating the object to be inspected about its axis.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2667183A JPS59151008A (en) | 1983-02-18 | 1983-02-18 | Method for inspecting appearance of circular object |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2667183A JPS59151008A (en) | 1983-02-18 | 1983-02-18 | Method for inspecting appearance of circular object |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59151008A JPS59151008A (en) | 1984-08-29 |
| JPH0551845B2 true JPH0551845B2 (en) | 1993-08-03 |
Family
ID=12199859
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2667183A Granted JPS59151008A (en) | 1983-02-18 | 1983-02-18 | Method for inspecting appearance of circular object |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59151008A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2119471A1 (en) * | 1992-07-20 | 1994-02-03 | Pio Meyer | Apparatus for driving a wobbling body |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4931345A (en) * | 1972-06-16 | 1974-03-20 | ||
| JPS5048955A (en) * | 1973-08-31 | 1975-05-01 | ||
| JPS55164304A (en) * | 1979-06-11 | 1980-12-22 | Hitachi Ltd | Mirror surface check unit |
| JPS58219441A (en) * | 1982-06-15 | 1983-12-20 | Hajime Sangyo Kk | Apparatus for detecting defect on surface of convex object |
-
1983
- 1983-02-18 JP JP2667183A patent/JPS59151008A/en active Granted
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4931345A (en) * | 1972-06-16 | 1974-03-20 | ||
| JPS5048955A (en) * | 1973-08-31 | 1975-05-01 | ||
| JPS55164304A (en) * | 1979-06-11 | 1980-12-22 | Hitachi Ltd | Mirror surface check unit |
| JPS58219441A (en) * | 1982-06-15 | 1983-12-20 | Hajime Sangyo Kk | Apparatus for detecting defect on surface of convex object |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59151008A (en) | 1984-08-29 |
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