JPH0781928B2 - Structure measuring device - Google Patents
Structure measuring deviceInfo
- Publication number
- JPH0781928B2 JPH0781928B2 JP61210730A JP21073086A JPH0781928B2 JP H0781928 B2 JPH0781928 B2 JP H0781928B2 JP 61210730 A JP61210730 A JP 61210730A JP 21073086 A JP21073086 A JP 21073086A JP H0781928 B2 JPH0781928 B2 JP H0781928B2
- Authority
- JP
- Japan
- Prior art keywords
- subject
- transparent body
- cylindrical transparent
- light source
- eccentricity
- 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
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/30—Testing of optical devices, constituted by fibre optics or optical waveguides
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- General Physics & Mathematics (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Testing Of Optical Devices Or Fibers (AREA)
- Light Guides In General And Applications Therefor (AREA)
Description
【発明の詳細な説明】 〈産業上の利用分野〉 本発明は例えば石英系光ファイバ母材のコア中心位置と
クラッド中心位置との差、すなわち偏心量を、該母材を
側方から観測することにより測定する構造測定装置に関
する。DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention observes, for example, the difference between the core center position and the clad center position of a silica optical fiber preform, that is, the eccentricity, from the side of the preform. The present invention relates to a structure measuring device for measuring.
〈従来の技術と問題点〉 光ファイバの偏心量を精度良く測定するということは、
特にコア径が小さいシングルモード光ファイバにおいて
は接続損失を低減するという観点から重要である。<Conventional technology and problems> Measuring the eccentricity of an optical fiber with high precision means
In particular, it is important in a single mode optical fiber having a small core diameter from the viewpoint of reducing splice loss.
従来における光ファイバの偏心量を測定する方法として
は、光ファイバの端面を鏡面に切断し、その切断面を顕
微鏡、ITV等で観測するというものであった。しかしな
がら、光ファイバの外径は標準的なもので125μｍと小
さいことから、接続損失への影響を考慮して偏心量を測
定するためには0.1μｍ程度以下の測定精度が要求され
るが、観測に用いる波長（通常0.5μｍ程度の可視域の
波長を用いる）に比較して小さな値であるため所要精度
を満足する測定を行うことは非常に困難であった。A conventional method for measuring the amount of eccentricity of an optical fiber is to cut the end surface of the optical fiber into a mirror surface and observe the cut surface with a microscope, ITV, or the like. However, since the outer diameter of the optical fiber is standard, which is as small as 125 μm, a measurement accuracy of about 0.1 μm or less is required to measure the amount of eccentricity in consideration of the effect on splice loss. It is very difficult to perform the measurement satisfying the required accuracy because it is a smaller value than the wavelength used for (usually, a wavelength in the visible region of about 0.5 μm is used).
因に、石英系光ファイバは通常プリフォームと呼ばれる
光ファイバと相似な構造を有する母材を高温溶融線引し
て得られるが、このことより母材の構造パラメータを測
定し、それによって光ファイバの構造パラメータを推定
することが可能と考えられる。従来より、母材の測定と
しては母材の側方から測定光を照射し、コア部の屈折率
分布の変化により生じる光線の屈折角を求め、これによ
ってコア部の屈折率分布を推定する方法は知られている
が、コア中心位置とクラッド中心位置との差（偏心量）
を精度良く測定することは行われていなかった。By the way, a silica-based optical fiber can be obtained by drawing a base material having a structure similar to that of an optical fiber, which is usually called a preform, by high-temperature fusion drawing. It is considered possible to estimate the structural parameters of Conventionally, a method of estimating the refractive index distribution of the core part by irradiating the measuring light from the side of the base material as the measurement of the base material and obtaining the refraction angle of the light beam generated by the change in the refractive index distribution of the core part Is known, but the difference between the core center position and the clad center position (amount of eccentricity)
Was not performed accurately.
本発明は上記従来の事情に鑑みなされたもので、光ファ
イバ母材の偏心量の測定を高精度に達成することができ
る構造測定装置を提供することを目的とする。The present invention has been made in view of the above-mentioned conventional circumstances, and an object of the present invention is to provide a structure measuring apparatus capable of highly accurately measuring the amount of eccentricity of an optical fiber preform.
〈問題点を解決するための手段〉 本発明の構造測定装置は、円筒状透明体より屈折率が高
い円柱状透明体を中心にして該円筒状透明体により取囲
み、該円柱状透明体と該円筒状透明体とを一体化して構
成した円柱状の被検体の構造を測定する装置において、
前記被検体を側方から照射する点光源と、前記被検体に
対し前記点光源の反対側に配設されて該被検体の中心よ
り近く且つ光軸に直交する観測面における当該被検体の
境界情報を含んだ部分像を取込む撮像光学系と、前記被
検体を長手方向及び光軸方向のいずれにも直交する方向
に移動させる被検体保持ステージと、前記撮像光学系の
境界情報及び前記被検体保持ステージの移動量情報から
各境界の相対位置を求めて前記被検体の偏心量を求める
データ処理装置とを備えたことを特徴とする。<Means for Solving Problems> The structure measuring apparatus of the present invention is a cylindrical transparent body surrounded by the cylindrical transparent body with a refractive index higher than that of the cylindrical transparent body as a center. In a device for measuring the structure of a cylindrical object, which is configured by integrating the cylindrical transparent body,
A point light source that illuminates the subject from the side, and a boundary of the subject on an observation plane that is disposed on the opposite side of the point light source to the subject and is closer to the center of the subject and orthogonal to the optical axis. An imaging optical system that captures a partial image containing information, a subject holding stage that moves the subject in a direction orthogonal to both the longitudinal direction and the optical axis direction, boundary information of the imaging optical system, and the subject. And a data processing device for obtaining the eccentric amount of the subject by obtaining the relative position of each boundary from the movement amount information of the sample holding stage.
〈実施例〉 本発明の一実施例に係る構造測定装置をその全体構成を
表す第１図を参照して説明する。<Example> A structure measuring apparatus according to an example of the present invention will be described with reference to FIG.
図示のように、本装置により偏心量を測定する被検体は
プリフォームと呼ばれる円柱状の光ファイバ母材１であ
り、この母材１は円筒状透明体２より屈折率の高い円柱
状透明体３を中心にして該円筒状透明体２により取囲
み、これら透明体2,3を一体化して構成されている。As shown in the figure, the subject whose eccentricity is measured by this device is a cylindrical optical fiber preform 1 called a preform, and this preform 1 is a cylindrical transparent body having a higher refractive index than the cylindrical transparent body 2. 3 is surrounded by the cylindrical transparent body 2, and these transparent bodies 2 and 3 are integrally formed.
この母材１は被検体保持ステージ４のＶブロック上に載
置保持されており、モータ５を作動してステージ４を図
中矢印ａ方向へ移動させると母材１も同方向へ移動す
る。母材１の一側部には点光源６が配設され、母材１の
他側部には撮像レンズ７を備えた撮像素子８が配設され
ており、母材１は点光源６から撮像レンズ７への光軸上
に直交して位置している。従って、ステージ４を移動さ
せることにより、母材１を長手方向及び光軸方向のいず
れにも直交する方向に移動させることができる。The base material 1 is placed and held on the V block of the subject holding stage 4, and when the motor 5 is operated to move the stage 4 in the direction of arrow a in the figure, the base material 1 also moves in the same direction. A point light source 6 is provided on one side of the base material 1, and an image sensor 8 having an imaging lens 7 is provided on the other side of the base material 1. It is positioned orthogonal to the optical axis to the imaging lens 7. Therefore, by moving the stage 4, the base material 1 can be moved in a direction orthogonal to both the longitudinal direction and the optical axis direction.
上記撮像レンズ７は母材１の一部を観測するようにその
倍率が設定されており、例えば円筒状透明体（クラッ
ド）２の外縁部、円筒状透明体（クラッド）２と円柱状
透明体（コア）３との境界部というように母材１の部分
像を撮像素子８に取込むようになっている。従って、例
えばクラッド２の外縁部の境界線2aは撮像素子８に接続
したモニタテレビ10に図示の如く観測され、上記ステー
ジ４の移動に伴って得られる走査線10aに沿った輝度デ
ータはコントローラ11を介してデータ処理装置であるCP
U12に送られる。尚、観測面は光軸に直交した面である
が、撮像レンズ７の焦点調整を行うことにより、この観
測面は母材１の中心を通る面Ｐより撮像レンズ７に近い
側の面Ｐ′に設定されている。これは、コア３とクラッ
ド２との境界面における光線の屈折を考慮した場合に、
この境界面が面Ｐより面Ｐ′において明瞭に識別される
ためである。The magnification of the imaging lens 7 is set so as to observe a part of the base material 1. For example, the outer edge portion of the cylindrical transparent body (clad) 2, the cylindrical transparent body (clad) 2 and the cylindrical transparent body. A partial image of the base material 1 such as a boundary with the (core) 3 is taken into the image sensor 8. Therefore, for example, the boundary line 2a at the outer edge of the clad 2 is observed as shown in the monitor television 10 connected to the image pickup device 8, and the brightness data along the scanning line 10a obtained with the movement of the stage 4 is obtained by the controller 11. Is a data processing device via CP
Sent to U12. Although the observation surface is a surface orthogonal to the optical axis, the observation surface is closer to the imaging lens 7 than the surface P passing through the center of the base material 1 by adjusting the focus of the imaging lens 7. Is set to. This is when considering the refraction of light rays at the interface between the core 3 and the clad 2,
This is because this boundary surface is more clearly identified on the surface P ′ than on the surface P.
また、上記ステージ４にはスケール14が付設されてお
り、ステージ４の移動量（位置）はスケール14により読
取られて表示器15を介してCPU12に送られる。従って、
モニタテレビ10上での絶対スケールを予め求めておくこ
とにより、ステージ４の位置データ及びモニタテレビ10
からの輝度データにより境界の位置データが求まる。す
なわち、これら位置データ及び輝度データをCPU12で処
理し、面Ｐ′におけるクラッド２の外縁部境界Ｐ′1,
P′4の位置座標をそれぞれＺ′1,Z′4，コア３とクラッ
ド２との境界面Ｐ′2,P′3の位置座標をそれぞれＺ′2,
Z′3とすると、コア３の中心Z5，クラッド２の中心Z6，
偏心量ΔＺはそれぞれ ΔＺ＝Z5−Z6により求まる。更に、図示していない回転
機構により母材１を軸回りに所定の角度ステップΔθで
回転させてΔＺ（ｉ×Δθ）（ここにｉ＝1,2,……）を
求め、これを正弦波曲線Asin（ｉ×Δθ＋）にフィテ
ィングさせることにより振幅Ａから偏心量が求まる。
尚、観測される偏心量Ａから真の偏真量Ａ′を求めるに
はクラッド２外縁部におけるレンズ効果を補正する必要
があり、近似的にＡ′は Ａ′＝A/n（n:屈折率） で得ることができる。A scale 14 is attached to the stage 4, and the movement amount (position) of the stage 4 is read by the scale 14 and sent to the CPU 12 via the display 15. Therefore,
By obtaining the absolute scale on the monitor TV 10 in advance, the position data of the stage 4 and the monitor TV 10 can be obtained.
The boundary position data can be obtained from the luminance data from. That is, the position data and the brightness data are processed by the CPU 12, and the outer edge boundary P ′ 1 of the cladding 2 on the surface P ′,
The position coordinates of P ′ 4 are Z ′ 1 and Z ′ 4 , respectively, and the position coordinates of the boundary surfaces P ′ 2 and P ′ 3 between the core 3 and the clad 2 are Z ′ 2 and Z ′ 2 , respectively.
Let Z ′ 3 be the center Z 5 of the core 3, the center Z 6 of the cladding 2,
The amount of eccentricity ΔZ is It can be obtained by ΔZ = Z 5 −Z 6 . Further, the base material 1 is rotated about the axis by a predetermined angle step Δθ by a rotation mechanism (not shown) to obtain ΔZ (i × Δθ) (where i = 1, 2, ...), and this is a sine wave. The eccentricity is obtained from the amplitude A by fitting the curve Asin (i × Δθ +).
In order to obtain the true declination amount A'from the observed decentering amount A, it is necessary to correct the lens effect at the outer edge of the cladding 2, and approximately A'is A '= A / n (n: refraction Rate) can be obtained.
上記の観測において、光源に点光源６を用いているた
め、母材１内の観測面の各点を通過する光線の角度がほ
ぼ一義的に決定され、撮像レンズ７の観測面を面Ｐ′と
しても面Ｐにおけるクラッド２の外縁部の輪郭が明瞭に
観測される。これに対し、光源に拡散性光源を用いた場
合、撮像レンズ７の観測面を面Ｐ′としたときには面Ｐ
は撮像レンズ７の合焦範囲から外れるためクラッド２外
縁部の明瞭な観測が行えず、また観測面を面Ｐとしたと
きにはコア３とクラッド２との境界面を明瞭なダークラ
インとして観測することができず、いずれにしても境界
の認識精度が低下する。In the above observation, since the point light source 6 is used as the light source, the angle of the light ray passing through each point on the observation surface in the base material 1 is almost uniquely determined, and the observation surface of the imaging lens 7 is set to the surface P ′. Even in this case, the contour of the outer edge of the clad 2 on the surface P is clearly observed. On the other hand, when a diffuse light source is used as the light source, when the observation surface of the imaging lens 7 is the surface P ′, the surface P
Is out of the focusing range of the imaging lens 7, so that the outer edge of the cladding 2 cannot be clearly observed, and when the observation surface is the surface P, the boundary surface between the core 3 and the cladding 2 must be observed as a clear dark line. However, in either case, the recognition accuracy of the boundary is reduced.
また、像の観測は対象物の全画像を撮像素子８に取込ん
で行うことも可能であるが、撮像素子８の分解能の制約
を考慮して対象物の部分像を観測するようにし、高い測
定精度を達成している。Further, the image can be observed by capturing the entire image of the object in the image sensor 8, but the partial image of the object is observed in consideration of the restriction of the resolution of the image sensor 8, which is high. Achieving measurement accuracy.
また、母材１を軸回りに回転させて偏心量の測定を行
い、測定された各偏心量を正弦波曲線にフィッティング
させるようにしているため、更に精度の高い測定が達成
されている。Further, since the eccentricity amount is measured by rotating the base material 1 around the axis and the measured eccentricity amounts are fitted to the sine wave curve, the measurement with higher accuracy is achieved.
尚、母材１の軸回りへの回転機能に加えて母材１の軸方
向への移動機能を追加すれば、母材１の偏心量及び偏心
方向の長手方向への分布を測定することができる。If the function of moving the base material 1 in the axial direction is added to the function of rotating the base material 1 around its axis, the amount of eccentricity of the base material 1 and the distribution in the longitudinal direction of the eccentric direction can be measured. it can.
（具体例） 点光源としてLEDを用い、外径φ20mmの単一モード光フ
ァイバプリフォームの偏心量ΔＺを測定し、第２図に示
すような結果を得た。撮像レンズとしては拡大率が４倍
となるものを用い、被検体保持ステージの位置読取用と
して0.1μｍ分解能のリニアスケールを用いた。母材の
同一断面に対して10回の測定を行ったところ、偏心量の
測定値の標準偏差は1.2μｍとなり、ほぼ0.01％の精度
で偏心率が測定可能であることが判った。(Specific Example) Using an LED as a point light source, the eccentricity ΔZ of a single mode optical fiber preform having an outer diameter of 20 mm was measured, and the results shown in FIG. 2 were obtained. An imaging lens having a magnifying power of 4 times was used, and a 0.1 μm resolution linear scale was used for reading the position of the subject holding stage. When the same cross section of the base material was measured 10 times, the standard deviation of the measured value of the eccentricity amount was 1.2 μm, and it was found that the eccentricity can be measured with an accuracy of about 0.01%.
尚、本発明は上記実施例に限定されるものではなく種々
の変更を加え得るものであり、また母材以外の被検体の
構造測定にも応用し得るものである。The present invention is not limited to the above-mentioned embodiment, but various changes can be made, and the present invention can be applied to the structure measurement of an object other than the base material.
〈発明の効果〉 本発明によれば被検体の偏心量を被破壊で極めて高精度
に測定することができる。また、光ファイバ母材の段階
で偏心量を測定できるため、中間工程においてその品質
を検査することができ、光ファイバ製造に多大なる利点
を供する。<Effects of the Invention> According to the present invention, the amount of eccentricity of the subject can be measured with high accuracy with destruction. Further, since the amount of eccentricity can be measured at the stage of the optical fiber preform, its quality can be inspected in the intermediate step, which is a great advantage for optical fiber production.
第１図は本発明の一実施例に係る構造測定装置を表す概
略構成図、第２図は実験結果を表すグラフである。 図面中、１は母材（被検体）、２は円筒状透明体（クラ
ッド）、３は円柱状透明体（コア）、４は被検体保持ス
テージ、６は点光源、８は撮像素子、12はCPU（データ
処理装置）である。FIG. 1 is a schematic configuration diagram showing a structure measuring apparatus according to one embodiment of the present invention, and FIG. 2 is a graph showing experimental results. In the drawing, 1 is a base material (subject), 2 is a cylindrical transparent body (clad), 3 is a cylindrical transparent body (core), 4 is a subject holding stage, 6 is a point light source, 8 is an image sensor, 12 Is a CPU (data processing device).
Claims (2)
体を中心にして該円筒状透明体により取囲み、該円柱状
透明体と該円筒状透明体とを一体化して構成した円柱状
の被検体の構造を測定する装置において、前記被検体を
側方から照射する点光源と、前記被検体に対し前記点光
源の反対側に配設されて該被検体の中心より近く且つ光
軸に直交する観測面における当該被検体の境界情報を含
んだ部分像を取込む撮像光学系と、前記被検体を長手方
向及び光軸方向のいずれにも直交する方向に移動させる
被検体保持ステージと、前記撮像光学系の境界情報及び
前記被検体保持ステージの移動量情報から各境界の相対
位置を求めて前記被検体の偏心量を求めるデータ処理装
置とを備えたことを特徴とする構造測定装置。1. A circle formed by surrounding a cylindrical transparent body having a refractive index higher than that of the cylindrical transparent body by the cylindrical transparent body, and integrating the cylindrical transparent body with the cylindrical transparent body. In a device for measuring the structure of a column-shaped object, a point light source that irradiates the object from the side, and a light source that is disposed on the opposite side of the point light source to the object and is closer to the center of the object An imaging optical system that captures a partial image including boundary information of the subject on an observation plane orthogonal to the axis, and a subject holding stage that moves the subject in a direction orthogonal to both the longitudinal direction and the optical axis direction. And a data processing device for obtaining the relative position of each boundary from the boundary information of the imaging optical system and the movement amount information of the subject holding stage to obtain an eccentricity amount of the subject. apparatus.
せたときに順次得られる偏心量を正弦波曲線にフィッテ
ィングしてその振幅から偏心量を求めることを特徴とす
る特許請求の範囲第１項記載の構造測定装置。2. The data processing apparatus according to claim 1, wherein the eccentricity amount sequentially obtained when the subject is rotated about an axis is fitted to a sine wave curve to obtain the eccentricity amount from the amplitude. The structure measuring device according to item 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61210730A JPH0781928B2 (en) | 1986-09-09 | 1986-09-09 | Structure measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61210730A JPH0781928B2 (en) | 1986-09-09 | 1986-09-09 | Structure measuring device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6366435A JPS6366435A (en) | 1988-03-25 |
| JPH0781928B2 true JPH0781928B2 (en) | 1995-09-06 |
Family
ID=16594157
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61210730A Expired - Fee Related JPH0781928B2 (en) | 1986-09-09 | 1986-09-09 | Structure measuring device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0781928B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02248835A (en) * | 1989-03-23 | 1990-10-04 | Fujikura Ltd | Measurement of eccentricity of core for optical fiber base material |
| JP5591818B2 (en) * | 2009-10-26 | 2014-09-17 | 株式会社フジクラ | Inspection apparatus and inspection method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6353403A (en) * | 1986-08-25 | 1988-03-07 | Furukawa Electric Co Ltd:The | Measurement of eccentricity for light transmitting long-sized body |
-
1986
- 1986-09-09 JP JP61210730A patent/JPH0781928B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6366435A (en) | 1988-03-25 |
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