JPS59211811A - Surface roughness measuring apparatus - Google Patents
Surface roughness measuring apparatusInfo
- Publication number
- JPS59211811A JPS59211811A JP8572483A JP8572483A JPS59211811A JP S59211811 A JPS59211811 A JP S59211811A JP 8572483 A JP8572483 A JP 8572483A JP 8572483 A JP8572483 A JP 8572483A JP S59211811 A JPS59211811 A JP S59211811A
- Authority
- JP
- Japan
- Prior art keywords
- measured
- plane
- light
- interference
- surface roughness
- 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.)
- Pending
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/30—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces
- G01B11/303—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces using photoelectric detection means
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は磁気テープ、磁気ディスクなどの軟質物の表面
のめらさを光学的に非接触で測定する装置に関するもの
である。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an apparatus for optically and non-contactly measuring the surface roughness of a soft material such as a magnetic tape or a magnetic disk.
従来の表面ららさ測定器は被測定物に触針を接触させ、
その触針の振動を電気信号に変換するか、または触針に
連結した鏡の変位を光学的に増幅しこの増幅変位量から
表面あらさを測定するものである。Conventional surface roughness measuring instruments bring a stylus into contact with the object to be measured.
The vibration of the stylus is converted into an electrical signal, or the displacement of a mirror connected to the stylus is optically amplified, and the surface roughness is measured from the amount of amplified displacement.
しかし、このような測定器では、触針の接触圧力による
被測定物表面の変形および損傷などを防止するため、触
針の接触圧力は極力低く設定する必要が套る。したがっ
て、検出速度が遅いばかシでなく、精度、安定性および
簡便性などにおいて問題がある。However, in such a measuring device, the contact pressure of the stylus must be set as low as possible in order to prevent deformation and damage to the surface of the object to be measured due to the contact pressure of the stylus. Therefore, there are problems not only in the slow detection speed but also in accuracy, stability, and simplicity.
そこで表面ろらさを、ンーザ光を使用して基準面とのギ
ャップの変化となし、光学的に測定する手段が提案され
ている。このような手段は被測定物を移動させる際、機
械的なガタによシ誤差を発生する欠点がある。Therefore, a method has been proposed in which the surface roughness is measured optically by measuring the change in the gap between the surface and the reference surface using laser light. Such means has the disadvantage that errors occur due to mechanical play when moving the object to be measured.
本発明は上記欠点を解消し、被測定物の表面あらさを高
精度に、かつ簡便に測定することを目的とするものであ
る。SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to measure the surface roughness of an object to be measured easily and with high precision.
本発明は上記目的を達成するために、レーザ発振器、ビ
ームスプリッタ、集光レンズ、集光を反射する基準面、
この基準面と平行に設けた被測定物固定面、前記基準面
と被測定物固定面を一体として移動させる手段およびビ
ームスプリッタの側方に対設した光センサなどによシ構
成し、前記基準面と被測定物表面からの両反射光の干渉
によシ生ずる干渉縞を前記移動手段を介して移動させ、
この干渉縞の移動を光センサにより検出して被測定物の
表面ららさを測定するものにしたものである。In order to achieve the above object, the present invention includes a laser oscillator, a beam splitter, a condensing lens, a reference surface that reflects condensed light,
The object to be measured is fixed to a surface parallel to the reference surface, a means for moving the reference surface and the object to be measured as one unit, and an optical sensor arranged opposite to the side of the beam splitter. moving interference fringes caused by interference of both reflected light from the surface and the surface of the object to be measured via the moving means;
The movement of the interference fringes is detected by an optical sensor to measure the surface roughness of the object to be measured.
以下本発明の一実施例を図面について説明する。 An embodiment of the present invention will be described below with reference to the drawings.
第１図において、１は単色光を発する光源例えばレーザ
発振器、２はレーザ発振器１から発振されるレーザビー
ムを透過または反射させるビームスプリッタ、３はビー
ムスグリツタ２を透過した光を集光する集光レンズ、４
は基準平面、５は基□準平面４を支持し、基準平面４と
平行な平面５ａを備える支持台、６は前記平面５ａ上に
固定された被測定物、例えば不透明な磁気テープ、７は
前記支持台５を矢印９方向に移動させる手段、例えば移
動台、８はビームスグリツタ２の側方に対向するように
設けられた光センサで、この光センサ８は入射光を電気
信号に変換する光検出器を線状に配置したアレイセンサ
である。In FIG. 1, 1 is a light source that emits monochromatic light, such as a laser oscillator, 2 is a beam splitter that transmits or reflects the laser beam emitted from the laser oscillator 1, and 3 is a condenser that collects the light that has passed through the beam sinter 2. optical lens, 4
5 is a reference plane, 5 is a support base that supports the reference plane 4 and has a plane 5a parallel to the reference plane 4, 6 is an object to be measured fixed on the plane 5a, for example, an opaque magnetic tape, and 7 is an opaque magnetic tape. Means for moving the support base 5 in the direction of the arrow 9, for example a moving base, 8 is an optical sensor provided facing the side of the beam sinter 2, and this optical sensor 8 converts incident light into an electrical signal. This is an array sensor with photodetectors arranged in a line.
次に上記のような構成からなる本実施例の作用について
説明する。Next, the operation of this embodiment configured as described above will be explained.
レーザ発振器１から発振されたレーザビーム１０は、ビ
ームスプリッタ２を透過して集光レンズ３に至り、この
集光レンズ３で集光された光の一部は基準平面４を透過
し、磁気テープ６の表面に焦点を結び、こ＼で反射され
る。この反射光をＢ１と称す。前記集光レンズ３で集光
された光の残部は基準平面４で反射される。この反射光
をＢ２と称す。前記反射光Ｂ１は集光レンズ３に至シ、
ここで平行光（平面波）となってビームスプリッタ２に
至シ、こ＼で反射されてアレイセ／す８に人。A laser beam 10 emitted from a laser oscillator 1 passes through a beam splitter 2 and reaches a condensing lens 3. A part of the light condensed by this condensing lens 3 passes through a reference plane 4 and is attached to a magnetic tape. It focuses on the surface of 6 and is reflected from this. This reflected light is called B1. The remainder of the light condensed by the condenser lens 3 is reflected by the reference plane 4. This reflected light is called B2. The reflected light B1 reaches the condensing lens 3,
Here, it becomes parallel light (plane wave) and reaches the beam splitter 2, where it is reflected and hits the array unit 8.
射する。shoot
一方、基準平面４で反射された光Ｂ２は、基準平面４が
集光レンズ３の焦点と一致していないから球面波となる
。この球面波は、基準平面４と磁気テープ６との距離が
短かいときには、ビームの拡が９はそれ程大きくないの
で、前記反射光Ｂ１と同一光路を経て２−一部スプリッ
タ２に至シ、ここで反射されてアレイセンサ８に至る。On the other hand, the light B2 reflected by the reference plane 4 becomes a spherical wave because the reference plane 4 does not coincide with the focal point of the condenser lens 3. When the distance between the reference plane 4 and the magnetic tape 6 is short, the beam spread 9 is not so large, so this spherical wave passes through the same optical path as the reflected light B1 and partially reaches the splitter 2. It is reflected here and reaches the array sensor 8.
この場合、前記反射光Ｂ１とＢ２は光路長差Δｔに応じ
た干渉信号を発生する。その光路長差Δｔｒｉ、基準平
面４と磁気テープ６の表面との距離８に起因するもの（
ΔＡｔ ）と、反射光Ｂｌ。In this case, the reflected lights B1 and B2 generate an interference signal according to the optical path length difference Δt. The optical path length difference Δtri is caused by the distance 8 between the reference plane 4 and the surface of the magnetic tape 6 (
ΔAt) and reflected light Bl.
Ｂ２がそれぞれ平面波および球面波であることに起因す
るもの（Δｔｚ）として分けることができる。It can be divided into two types (Δtz) due to the fact that B2 is a plane wave and a spherical wave, respectively.
前記ΔｔＩは下記（１）式で表わされることは容易に理
解される。It is easily understood that the ΔtI is expressed by the following formula (1).
Δｔ１−２６ ・・・（υついで、上記
Δｔ２を求めるために、まず平面波と球面波との間に生
ずる光路長差を求める。Δt1-26...(υNext, in order to find the above-mentioned Δt2, first find the optical path length difference that occurs between the plane wave and the spherical wave.
第２図において、Ｚ軸方、向に進行する平面波Ｃおよび
点Ａから発した球面波りが、点Ａから距離ｔの位置でＺ
軸に垂直に立てた平面Σに入射す−る場合、Ｚ軸と平面
Σとの交点を０とし、とのＯから距離γの位置における
二つの光の光路長差Δｔ′を求める。この光路長差ΔＬ
′が点Ｏで零であるとすると、Δｔ′は下記（２）式で
表わされる。In Fig. 2, a plane wave C traveling in the Z-axis direction and a spherical wave originating from point A move toward Z at a distance t from point A.
When the light is incident on a plane Σ perpendicular to the axis, the intersection of the Z axis and the plane Σ is set to 0, and the optical path length difference Δt' between the two lights at a distance γ from O is determined. This optical path length difference ΔL
Assuming that ' is zero at point O, Δt' is expressed by the following equation (2).
・・・（２）
したがって、光源の波長をλとすると、垂直面Σ上にお
ける干渉パターンは下記（３）（４１式を満足する位置
にそれぞれ明リングＥと暗リングＦが生ずる。(2) Therefore, if the wavelength of the light source is λ, the interference pattern on the vertical plane Σ will be a bright ring E and a dark ring F at positions that satisfy the following equation (3) (41).
Δｔ／＝ｎλ ・・・（３）λ
ΔＺ ／ ＝＝ ｎλ＋−・・・（４）ま
たソし１ｌ＝＝Ｑ、ｉ、２・・・・・・これよシ第１゛
図の磁気チーブ６おｉび基準平面４の各表面よで反射し
た光Ｂｌ、Ｂ２がアレイセンサ８の位置でｉ生ずる干渉
パターンを求めることができる。Δt/=nλ...(3) λ ΔZ/== nλ+-...(4) So 1l==Q, i, 2...This is the magnetic tube in Figure 1 It is possible to obtain an interference pattern caused by the lights B1 and B2 reflected from each surface of the reference plane 4 and the array sensor 8 at the position of the array sensor 8.
基準平面４と磁気テープ６との距離δ、果先光レンズの
焦点距離をｆとすれば、基準平面４で反射された光Ｂ２
は基準平面４から距離δの位置、すなわち集光レンズ３
から距離ｆ−２δの位置で一点に果まる。この光が集光
レンズ３を通ると、集光レンズ３の後方の位置Ｗから発
した球面波りに変わるとすれば、前記ｆ１ δ、Ｗとの
間には下記（５）式が成立する。If the distance between the reference plane 4 and the magnetic tape 6 is δ, and the focal length of the tip optical lens is f, then the light B2 reflected by the reference plane 4 is
is the position at a distance δ from the reference plane 4, that is, the condenser lens 3
It ends at a point at a distance f-2δ from . When this light passes through the condenser lens 3, it changes into a spherical wave emitted from the position W behind the condenser lens 3, and the following formula (5) holds true between f1 δ and W. .
この（５）式よシＷは下記（６）式で表わされる。From this equation (5), W is expressed by the following equation (6).
いマ、集光レンズ３からビームスプリッタ２を経てアレ
イセンサ８に至る距離をＬとすれば、アレイセンサ８の
位置で前記反射光Ｂｌ、Ｂ２の間に生ずる光路長差のう
ち、反射光Ｂ１．“Ｂ２がそれぞれ平面波（ｊ？よび球
面波りであることによる光路長差Δｔ２は前記（２）式
にｔ＝Ｗ＋Ｌを代入してえられる。一般にＷ＋Ｌ））ｒ
であるから、前記Δｔｚ／ｄ下記（７ン式で表わされる
。Now, if the distance from the condenser lens 3 to the array sensor 8 via the beam splitter 2 is L, then of the optical path length difference that occurs between the reflected lights B1 and B2 at the position of the array sensor 8, the reflected light B1 ．． "The optical path length difference Δt2 due to the fact that B2 is a plane wave (j?) and a spherical wave can be obtained by substituting t=W+L into the above equation (2). In general, W+L)) r
Therefore, the above-mentioned Δtz/d is expressed by the following formula.
したがって、アレイセンサ８の位置における反射光Ｂｌ
、Ｂ２の光路長差Δ２（＝Δｔ！十Δｔｚ）は下記（８
）式で表わされる。Therefore, the reflected light Bl at the position of the array sensor 8
, B2 optical path length difference Δ2 (=Δt! +Δtz) is as follows (8
) is expressed by the formula.
満足する位置で明、暗り／グをそれぞｎ発生する。Brightness and darkness/g are generated n times at a satisfying position.
したがって、移動台７を介してレーザビームの来光位置
を移動させると、磁気テープ６の表面の凹凸に応じてδ
は微小変化するからΔｔも変化する。Therefore, when the arrival position of the laser beam is moved via the moving table 7, δ
Since Δt changes minutely, Δt also changes.
ところが、一般に前記（８）式において、第２項Δｔ２
の変化分（第１項Δｔの変化分であるから、第２項Δｔ
２は無視できる。例えばδ＝０．５■、ｆ＝２ ｓｔｓ
＋、Ｌ＝１０００１１１１． ｒ＝２ｔａｓとし、磁
気テープ６表面の凹凸のためにδが０．５ｓｍから（０
，５−）−０，００１）＋ｍに変化（１μｍ変化）した
とすれば、前記Δ７１＋Δｔ２の変化はそれぞれ２μｍ
。However, generally in equation (8), the second term Δt2
(Since it is the change in the first term Δt, the second term Δt
2 can be ignored. For example, δ=0.5■, f=2 sts
+, L=10001111. r=2tas, and due to the unevenness of the surface of the magnetic tape 6, δ ranges from 0.5sm to (0
,5-)-0,001)+m (1 μm change), the change in Δ71+Δt2 is 2 μm each.
.
０．００２μｍである。It is 0.002 μm.
したがって、アレイセンサ８で干渉縞の移動をλ
観則す庇は、一つの干渉縞の移動が−の凹凸（磁気テー
プ表面）に相当し、その干渉縞が中心から外方へ同うと
きに（は、集光位置の移動に伴って磁気テープ６０表面
が突出する場合でめ９、逆に干渉縞が外方から内方へ向
うときには、磁気テープ６の表面がへこむ場合でりゐこ
とがわかる。Therefore, the movement of the interference fringes is observed by the array sensor 8 as λ, and the movement of one interference fringe corresponds to a negative unevenness (magnetic tape surface), and when the interference fringes move outward from the center, (This is a case where the surface of the magnetic tape 60 protrudes as the light condensing position moves.) Conversely, when the interference fringes move from the outside to the inside, the surface of the magnetic tape 6 may become depressed. Recognize.
以上説明したように本発明に工れは、レーザビームの来
光位置を被測定物の表面上を横方向に移動さぜる場合、
上下方向に多少ずｎても基準面と被測定物との位置関係
は不変であるので、表面めらさゲ被測定物表面の凹凸に
よる基準面との距離変化として正確に測定することがで
きる。As explained above, the advantage of the present invention is that when the position of the laser beam is moved laterally on the surface of the object to be measured,
Since the positional relationship between the reference surface and the object to be measured does not change even if it moves slightly in the vertical direction, it is possible to accurately measure the change in distance from the reference surface due to the unevenness of the surface of the object to be measured. .
また本発明でＶよ、元センサで干渉縞のパターン全観測
しているので、その干渉縞の間隔を補整することによシ
、測足ｄ度をより一層に向上させることが可能である利
点かめる。Another advantage of the present invention is that since the entire pattern of interference fringes is observed using the original sensor, it is possible to further improve the degree of measurement by correcting the interval of the interference fringes. Kameru.
第１図は本発明の狭面あらさ測定装置の一実施例を示す
概略図、第２図および第３図は同実施例の作用説チ」図
でるる。
１・・・光源、２・・・ビームスプリッタ、３・・・来
光レンズ、４・・・基準面、５ａ・・・被測定物置足面
、６・・・被測定物、７・・・移動台、８・・・光セン
サ。
代理人 升埋士 高橋明夫
第１図
箭２図
Σ
第 ３ 図FIG. 1 is a schematic diagram showing an embodiment of the narrow surface roughness measuring device of the present invention, and FIGS. 2 and 3 are diagrams showing the operation of the same embodiment. DESCRIPTION OF SYMBOLS 1... Light source, 2... Beam splitter, 3... Coming lens, 4... Reference plane, 5a... Measured object foot surface, 6... Measured object, 7... Moving table, 8... optical sensor. Agent: Masu buryer Akio Takahashi Figure 1 Figure 2 Σ Figure 3
Claims (1)
させるビームスグリツタと、このビームスプリッタから
の光を集光する集光レンズと、この集光レンズからの集
光を反射する基準面と、この基準面と平行に設け一←れ
た被測定物固定面と、前記基準面および被測定物固定面
を一体として移動させる手段と、前記ビームスグリツタ
の側方に対向するように設けた光センサとからなシ、前
記基準面と被測定物表面からの両反射光の干渉によシ生
ずる干渉縞を前記移動手段を介して移動させ、この干渉
縞の移動を光センサによシ検出して被測定物の表面らら
さを測定するようにしたことを特徴とする表面あらさ測
定装置。A light source that emits monochromatic light, a beam slit that transmits or reflects the light beam, a condensing lens that condenses the light from the beam splitter, and a reference surface that reflects the condensed light from the condensing lens. An object fixing surface provided parallel to the reference surface, a means for moving the reference surface and the object fixing surface as one unit, and a light beam provided opposite to the side of the beam sinter. The sensor moves interference fringes caused by interference of both reflected light from the reference surface and the surface of the object to be measured through the moving means, and detects the movement of the interference fringes by the optical sensor. A surface roughness measuring device characterized in that it measures the surface roughness of an object to be measured.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8572483A JPS59211811A (en) | 1983-05-18 | 1983-05-18 | Surface roughness measuring apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8572483A JPS59211811A (en) | 1983-05-18 | 1983-05-18 | Surface roughness measuring apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS59211811A true JPS59211811A (en) | 1984-11-30 |
Family
ID=13866789
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8572483A Pending JPS59211811A (en) | 1983-05-18 | 1983-05-18 | Surface roughness measuring apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59211811A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6325503A (en) * | 1986-07-17 | 1988-02-03 | Ee D S:Kk | Surface roughness meter |
| EP0818667A1 (en) * | 1996-07-10 | 1998-01-14 | Compagnie Industrielle Des Lasers Cilas | Device for determining the form of a wave-front transmitted by a transparent plate with parallel faces |
-
1983
- 1983-05-18 JP JP8572483A patent/JPS59211811A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6325503A (en) * | 1986-07-17 | 1988-02-03 | Ee D S:Kk | Surface roughness meter |
| EP0818667A1 (en) * | 1996-07-10 | 1998-01-14 | Compagnie Industrielle Des Lasers Cilas | Device for determining the form of a wave-front transmitted by a transparent plate with parallel faces |
| FR2751069A1 (en) * | 1996-07-10 | 1998-01-16 | Cilas | DEVICE FOR DETERMINING THE SHAPE OF THE WAVE SURFACE TRANSMITTED BY A TRANSPARENT PIECE WITH SUBSTANTIALLY PARALLEL FACES |
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