JPH055081B2 - - Google Patents

Info

Publication number
JPH055081B2
JPH055081B2 JP59030113A JP3011384A JPH055081B2 JP H055081 B2 JPH055081 B2 JP H055081B2 JP 59030113 A JP59030113 A JP 59030113A JP 3011384 A JP3011384 A JP 3011384A JP H055081 B2 JPH055081 B2 JP H055081B2
Authority
JP
Japan
Prior art keywords
lens
light source
optical system
fiber
numerical aperture
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
Application number
JP59030113A
Other languages
Japanese (ja)
Other versions
JPS60173516A (en
Inventor
Juji Ueno
Hisami Nishi
Minoru Tooyama
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Sheet Glass Co Ltd
Original Assignee
Nippon Sheet Glass Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nippon Sheet Glass Co Ltd filed Critical Nippon Sheet Glass Co Ltd
Priority to JP3011384A priority Critical patent/JPS60173516A/en
Publication of JPS60173516A publication Critical patent/JPS60173516A/en
Publication of JPH055081B2 publication Critical patent/JPH055081B2/ja
Granted legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
    • G02B6/4206—Optical features
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Lenses (AREA)
  • Optical Couplings Of Light Guides (AREA)

Description

【発明の詳細な説明】 〔発明の技術分野〕 本発明は光源からの拡散光束を光伝送フアイバ
に入射させる光学系に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an optical system that makes a diffused light beam from a light source enter an optical transmission fiber.

〔発明の技術的背景〕[Technical background of the invention]

半導体レーザ等の光源から放射される特定波長
の拡散光を径の小さい光伝送フアイバ、特にシン
グルモードフアイバに入射させる場合、洩光損失
を可及的に小さく抑えるために低収差で効率良く
入射させることが必要である。 When making diffused light of a specific wavelength emitted from a light source such as a semiconductor laser enter a small-diameter optical transmission fiber, especially a single-mode fiber, it is made to enter efficiently with low aberrations in order to minimize leakage loss. It is necessary.

特に組み立て誤差に起因する軸外入射でも使用
できるようにコマ収差を充分に補正しておく必要
がある。また光学系は小型、軽量であることが要
求されされる。 In particular, it is necessary to sufficiently correct coma aberration so that it can be used even with off-axis incidence caused by assembly errors. Further, the optical system is required to be small and lightweight.

従来この種の光源結合用光学系の典型的なもの
としては、光源と光伝送フアイバとの間に単一の
自己集束型レンズを配置したものが知られてい
る。自己集束型レンズは周知のように屈折率が中
心軸上で最大で半径方向にパラボリツクに漸減し
外周で最小となる屈折率分布をもつ透明円柱体か
らなる。上記のような単一の自己集束型レンズの
場合軸上収差を小さくするためには屈折率分布の
制御が極めて難しく、また仮りに軸上収差を満足
できる程度まで小さくし得たとしても、軸外収
差、特にコマ収差が大きいまま残るため、例えば
組み立て時の誤差等に起因して光源がレンズ光軸
からずれたときに収差が大きくなり、フアイバに
入射されない洩光損失が急激に増大するという問
題がある。一例として最も一般的に使用されてい
るコア径10μｍのシングルモードフアイバに、光
軸に対し直角方向に0.1mmずれて光源からの光線
を従来の単一の自己集束型レンズを介して入射さ
せたときのスポツトダイアグラムを第３図に示
す。 Conventionally, a typical optical system for coupling light sources of this type is one in which a single self-focusing lens is disposed between a light source and a light transmission fiber. As is well known, a self-focusing lens consists of a transparent cylindrical body having a refractive index distribution where the refractive index is maximum on the central axis, gradually decreases parabolically in the radial direction, and is minimum at the outer periphery. In the case of a single self-focusing lens like the one mentioned above, it is extremely difficult to control the refractive index distribution in order to reduce the axial aberration, and even if the axial aberration can be reduced to a satisfactory level, the axial External aberrations, especially comatic aberrations, remain large, so when the light source shifts from the optical axis of the lens due to errors during assembly, for example, the aberrations become larger and the loss of leakage light that does not enter the fiber increases rapidly. There's a problem. As an example, the most commonly used single-mode fiber with a core diameter of 10 μm was entered with a light beam from a light source shifted by 0.1 mm perpendicular to the optical axis through a single conventional self-focusing lens. The spot diagram at that time is shown in Figure 3.

同図において７はシングルモードフアイバのコ
アを示し、黒点８はフアイバ端面を含む平面を光
線が横切る位置を示す。 In the figure, 7 indicates the core of the single mode fiber, and black dots 8 indicate the positions where the light ray crosses the plane including the fiber end face.

第３図からレンズに入射した光線は一点に集ま
らず非常に大きく拡散し、フアイバコア７に入射
しない光線が相当量存在することがわかる。 It can be seen from FIG. 3 that the light rays incident on the lens do not converge at one point but are greatly diffused, and that there is a considerable amount of light rays that do not enter the fiber core 7.

上記のような収差を補正した光学系は屈折率の
一様な通常の球面レンズ３ないし４枚で構成する
ことは可能であるが、光学系がかなり大きなもの
になり、またレンズの研磨加工、組立てに手間が
かかりコストアツプになるという問題がある。 Although it is possible to construct an optical system that corrects the above aberrations using three or four ordinary spherical lenses with uniform refractive index, the optical system would be quite large and would require lens polishing and polishing. There is a problem that assembly is time consuming and costs increase.

〔発明の目的〕[Purpose of the invention]

本発明の目的は、上記従来の欠点を解消し、軸
上収差のみならず軸外収差も小さく、しかもレン
ズ端面がすべて平面でよいため研磨加工組み立て
が極めて容易で安価に量産できる。小型、軽量の
光源結合用光学系を提供することである。 It is an object of the present invention to eliminate the above-mentioned conventional drawbacks, to have small not only axial aberrations but also to have small off-axis aberrations, and because all lens end faces may be flat, polishing and assembly are extremely easy and mass production is possible at low cost. An object of the present invention is to provide a compact and lightweight optical system for coupling light sources.

〔発明の構成〕[Structure of the invention]

上記目的を達成する本発明の光学系は、光源と
光フアイバとの間に、中心からｒの距離における
屈折率ｎ(r)が、中心軸上の屈折率をnoとして n2（ｒ）＝no2｛１−（gr）2＋h4（gr）4＋h6（gr）6＋
h8
（gr）8＋…｝で表わされる円柱状の透明体からな
る２つの自己集束型レンズを光軸方向に並べて配
置し、該光学系の光源側の開口数を出射側開口数
よりも大とするとともに、前記係数h4について、
（第１レンズは−２以上で0.2以下の範囲、第２レ
ンズは0.8以上で2.0以下の範囲とすることを特徴
としている。 The optical system of the present invention that achieves the above object has a refractive index n(r) at a distance r from the center between a light source and an optical fiber, where the refractive index on the central axis is no, n 2 (r) = no 2 {1-(gr) 2 +h 4 (gr) 4 +h 6 (gr) 6 +
h 8
(gr) 8 +...} Two self-focusing lenses made of cylindrical transparent bodies are arranged side by side in the optical axis direction, and the numerical aperture on the light source side of the optical system is set larger than the numerical aperture on the output side. At the same time, for the coefficient h 4 ,
(The first lens has a range of -2 or more and 0.2 or less, and the second lens has a range of 0.8 or more and 2.0 or less.

〔実施例〕〔Example〕

以下本発明を図面にした実施例について詳細に
説明する。 Embodiments of the present invention illustrated in the drawings will be described in detail below.

第１図において１は本発明に係る光学系であ
り、半導体レーザ等の光源４からの拡散出射光５
は上記光学系１を通して集束され、シングルモー
ドフアイバ６のコア中に入射する。 In FIG. 1, reference numeral 1 denotes an optical system according to the present invention, in which diffused emitted light 5 is emitted from a light source 4 such as a semiconductor laser.
is focused through the optical system 1 and enters the core of the single mode fiber 6.

上記光学系１は２つの自己集束型レンズ２，３
を軸線を一致させ端面同士を密着させて配置して
構成されている。 The optical system 1 includes two self-focusing lenses 2 and 3.
are arranged with their axes aligned and their end faces in close contact with each other.

自己集束型レンズ２，３はガラス、合成樹脂等
の透明な円柱体からなり、両レンズ２，３の全て
の端面は光軸に垂直な平面である。また、両レン
ズ２，３はいずれも光軸からｒの距離における屈
折率ｎ(r)が、n2（ｒ）＝no2〔１−（gr）2＋h4（gr）4
＋
h6（gr）6＋h8（gr）8＋…〕……(1)の式で表わされる
屈折率分布を有している。 The self-focusing lenses 2 and 3 are made of transparent cylindrical bodies made of glass, synthetic resin, etc., and all end surfaces of both lenses 2 and 3 are planes perpendicular to the optical axis. Furthermore, the refractive index n(r) of both lenses 2 and 3 at a distance r from the optical axis is n 2 (r)=no 2 [1-(gr) 2 +h 4 (gr) 4
 +
h 6 (gr) 6 + h 8 (gr) 8 +…] It has a refractive index distribution expressed by the formula (1).

上記(1)式において、noは光軸上の屈折率、ｇ、
h4、h6、h8は屈折率分布定数である。 In the above equation (1), no is the refractive index on the optical axis, g,
h 4 , h 6 , and h 8 are refractive index distribution constants.

そして光学系１の光源側開口数NA1および出
射側開口数NA2がNA1＞NA2の関係となるよう
に光学系諸元が選ばれている。上記の開口数の関
係により、光源４から比較的大きな拡散角で放射
される光束は、大きな開口数をもつ光学系１の入
射面において効率良く補足され、また開口数が相
対的に小さい出射面側から、光源からの入射時よ
りも緩やかな角度で出射し集束されるので、開口
数が相対的に小さいシンルグモードフアイバに対
しても効率良く光源光を入射させることができ
る。 The optical system specifications are selected so that the light source side numerical aperture NA1 and the output side numerical aperture NA2 of the optical system 1 satisfy the relationship NA1 > NA2 . Due to the numerical aperture relationship described above, the light beam emitted from the light source 4 at a relatively large diffusion angle is efficiently captured at the entrance surface of the optical system 1, which has a large numerical aperture, and also at the exit surface, which has a relatively small numerical aperture. Since the light is emitted from the side at a gentler angle than when it enters from the light source and is focused, the light source light can be efficiently entered into a single mode fiber with a relatively small numerical aperture.

また、上記レンズ２，３の(1)式における４次項
係数h4に関し、光源側の第１レンズのh4を第２レ
ンズのh4よりも小にしてある。 Regarding the fourth-order term coefficient h 4 in equation (1) for the lenses 2 and 3, h 4 of the first lens on the light source side is made smaller than h 4 of the second lens.

この係数h4ついてさらに詳しく述べる。 This coefficient h 4 will be described in more detail.

自己集束型レンズ２，３の中心屈折率noおよ
び分布定数ｇの典型的な数値例としてno＝１，
658、ｇ＝0.2284mm-1を選び一方レンズの分布係
数h4を決めて収差の計算から球面収差を０にする
ような他方のレンズの分布係数h4を求める。そし
て両レンズ２，３の組み合せ光学系１の正弦条件
不満足量を計算してこの不満足量がほぼ０になら
ない場合は当初設定の分布係数h4の値を変えて上
記計算を正弦条件不満足量がほぼ０になるまで繰
り返して両レンズのh4の最適組み合せを求めた。
その結果を第２図に示す。光学系１の出射側の開
口数NA2については、シングルモードフアイバ
の最適スポツトサイズから求めてNA2＝0.108と
し、また光学系１の入射側の開口数NA1は光源
からの入射時における損失が1dB以下なるよう
NA1＝0.39としている。第２図のグラフにおいて
横軸は組み合せ光学系の全レンズ長Ｚと第１レン
ズのレンズ長Z1との比をあらわし、たて軸は(1)式
における４次項係数h4の値である。またパラメー
タのS1は光源と第１レンズ２の入射面２Ａとの距
離である。 Typical numerical examples of the central refractive index no and distribution constant g of the self-focusing lenses 2 and 3 are no=1,
658, g = 0.2284 mm -1 , determine the distribution coefficient h 4 of one lens, and calculate the distribution coefficient h 4 of the other lens that makes the spherical aberration 0 from the aberration calculation. Then, calculate the amount of unsatisfactory sine condition of the combined optical system 1 of both lenses 2 and 3, and if this unsatisfactory amount does not become almost 0, change the value of the initially set distribution coefficient h 4 and repeat the above calculation until the amount of unsatisfactory sine condition The optimum combination of h4 for both lenses was determined by repeating the process until it became almost 0.
The results are shown in FIG. The numerical aperture NA 2 on the output side of optical system 1 is determined from the optimal spot size of the single mode fiber and is set to NA 2 = 0.108, and the numerical aperture NA 1 on the input side of optical system 1 is determined by the loss at the time of incidence from the light source. so that it is less than 1dB.
NA 1 = 0.39. In the graph of Figure 2, the horizontal axis represents the ratio of the total lens length Z of the combined optical system to the lens length Z 1 of the first lens, and the vertical axis represents the value of the fourth-order term coefficient h 4 in equation (1). . Further, the parameter S 1 is the distance between the light source and the entrance surface 2A of the first lens 2.

第２図のグラフにおいて下方にある三本の曲線
A1，A2，A3はそれぞれS1＝0.8mm、1.363mm、2.0
mmにおける光源側レンズ２のh4の値を示し、上方
にある三本の曲線B1，B2，B3は上記曲線A1，
A2，A3上のh4の値に対応する最適（正弦条件不
満足量がほぼ０）なフアイバ側レンズ３のh4の数
値を示す。第２図から明らかなように両レンズ
２，３の組み合せ光学系においては光源側レンズ
２のh4の値をフアイバ側レンズ３のh4の値よりも
小さくすることにより広範囲な条件下で収差を充
分に小さい値にするとができる。そしてグラウに
示されるように光源側レンズ２のh4の望ましいh4
の値の範囲は−２≦h4≦0.2であり、またフアイ
バ側レンズ３の望ましいh4の範囲は0.8≦h4≦2.0
である。 The three curves at the bottom of the graph in Figure 2
A 1 , A 2 , A 3 are S 1 =0.8mm, 1.363mm, 2.0 respectively
It shows the h 4 value of the light source side lens 2 in mm, and the three upper curves B 1 , B 2 , B 3 are the above curves A 1 ,
The value of h 4 of the optimal fiber side lens 3 (the amount of unsatisfactory sine condition is almost 0) corresponding to the value of h 4 on A 2 and A 3 is shown. As is clear from Fig. 2, in the combined optical system of both lenses 2 and 3, by making the value of h 4 of the light source side lens 2 smaller than the value of h 4 of the fiber side lens 3, aberrations can be prevented under a wide range of conditions. can be made to a sufficiently small value. And the desired h 4 of h 4 of the light source side lens 2 as shown in Grau
The value range of is -2≦h 4 ≦0.2, and the desirable range of h 4 of the fiber side lens 3 is 0.8≦h 4 ≦2.0.
It is.

１つの数値例を示すと、レンズ２の入射面２Ａ
までの距離S1＝1.363mm、レンズ３の出射面３Ａ
からフアイバ端面までの距離S2＝10.399mm、両レ
ンズ２，３の中心屈折率no＝1.658、(1)式の定数
ｇ＝0.2284mm-1、第１レンズの長さZ1＝第２レン
ズの長さZ2＝2.940mmとしたとき、光源側レンズ
２の分布係数をh4＝−0.7、h6＝０、h8＝０とし、
フアイバ側レンズ３の各係数をh4＝1.16、h6＝
0.12、h8＝1.47に選べば組み合せ光学系の収差を
極小にすることができる。 To give one numerical example, the entrance surface 2A of the lens 2
Distance to S 1 = 1.363mm, exit surface 3A of lens 3
Distance from to the fiber end face S 2 = 10.399 mm, center refractive index no of both lenses 2 and 3 = 1.658, constant g in equation (1) = 0.2284 mm -1 , length of the first lens Z 1 = second lens When the length Z 2 = 2.940 mm, the distribution coefficient of the light source side lens 2 is h 4 = -0.7, h 6 = 0, h 8 = 0,
The coefficients of the fiber side lens 3 are h 4 = 1.16, h 6 =
By selecting 0.12 and h 8 =1.47, the aberration of the combined optical system can be minimized.

上記数値例の光学系１で光源が光軸と垂直方向
に0.1mmずれたときのシングルモードフアイバ端
面上でのスポツトダイアグラムを第４図に示す。 FIG. 4 shows a spot diagram on the end face of the single mode fiber when the light source is deviated by 0.1 mm in the direction perpendicular to the optical axis in the optical system 1 of the above numerical example.

第３図と第４図の比較から明らかなように、本
発明に係る光学系は軸外収差が極めて小さく、し
たがつて光源位置が光学系光軸から多少ずれてい
ても光源光が確実にフアイバコア内に入射し、結
合効率が非常に高い。 As is clear from the comparison between Figures 3 and 4, the optical system according to the present invention has extremely small off-axis aberrations, so even if the light source position is slightly deviated from the optical axis of the optical system, the light source light can be reliably transmitted. It enters the fiber core and has very high coupling efficiency.

〔発明の効果〕〔Effect of the invention〕

以上実施例で説明したように本発明の光学系は
軸外収差が非常に小さく、したがつて組み立て誤
差等に起因して光源と光学系光軸との間に多少の
ずれを生じたとしても、洩光損失をほとんど生じ
ることなくシングルモードフアイバの微小なコア
内に効率良く伝送される。同時に光源と光学系光
軸との軸合せの許容誤差が拡大するので、組み立
て作業もそれだけ容易化する。 As explained in the embodiments above, the optical system of the present invention has very small off-axis aberrations, so even if there is some misalignment between the light source and the optical axis of the optical system due to assembly errors etc. , is efficiently transmitted within the minute core of a single mode fiber with almost no leakage loss. At the same time, the tolerance for alignment between the light source and the optical axis of the optical system is increased, so the assembly work becomes easier.

さらに、２個の自己集束型レンズの組み合せで
あるためレンズ面の研磨加工は平面加工で良く、
したがつて微小径のレンズであつても極めて容易
に加工するとができ、球面レンズの組み合せ光学
系に比して製作が容易である。 Furthermore, since it is a combination of two self-focusing lenses, the lens surface can be polished by flat processing.
Therefore, even a lens with a minute diameter can be processed extremely easily, and it is easier to manufacture than an optical system combining spherical lenses.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明の一実施例を示す断面図、第２
図は本発明の光学系における第１レンズと第２レ
ンズの４次項係数h4の最適組み合せ範囲を示すグ
ラフ、第３図、第４図は光源光をレンズ光軸から
偏位させて入射させた場合のフアイバ端面上での
スポツトダイアグラムを示し、第３図は従来の単
一の自己集束型レンズを使用した場合であり、第
４図は本発明の光学系を使用した場合を示す。 １……光源結合用光学系、２，３……自己集束
型レンズ、４……光源、６……フアイバ。 FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is a graph showing the optimal combination range of the fourth-order term coefficient h 4 of the first lens and the second lens in the optical system of the present invention. Figures 3 and 4 are graphs showing the range of optimal combinations of the fourth-order term coefficient h 4 of the first lens and the second lens in the optical system of the present invention. FIG. 3 shows the spot diagram on the fiber end face when a conventional single self-focusing lens is used, and FIG. 4 shows the case when the optical system of the present invention is used. 1... Optical system for light source coupling, 2, 3... Self-focusing lens, 4... Light source, 6... Fiber.

Claims (1)

【特許請求の範囲】 １ 光源と光フアイバとの間に、中心からｒの距
離における屈折率ｎ(r)が、 n2（ｒ）＝n0 2｛１−（gr）2＋h4（gr）4＋h6（gr）6＋
h8
（gr）8＋…｝で表わされる円柱状の透明体からな
る２つの自己集束型レンズを光軸方向に並べて配
置し、該光学系の光源側の開口数を出射側開口数
よりも大とするとともに、前記係数h4について光
源側に位置するレンズ（第１レンズ）を−２≦h4
≦0.2の範囲内、他方のレンズ（第２レンズ）を
0.8≦h4≦2.0の範囲内としたことを特徴とする光
源・フアイバ結合用光学系。[Claims] 1. Between the light source and the optical fiber, the refractive index n(r) at a distance r from the center is n 2 (r)=n 0 2 {1−(gr) 2 +h 4 (gr ) 4 +h 6 (gr) 6 +
h 8
(gr) 8 +...} Two self-focusing lenses made of cylindrical transparent bodies are arranged side by side in the optical axis direction, and the numerical aperture on the light source side of the optical system is set larger than the numerical aperture on the output side. At the same time, regarding the coefficient h 4 , the lens located on the light source side (first lens) is -2≦h 4
Within the range of ≦0.2, the other lens (second lens)
An optical system for light source/fiber coupling, characterized in that it is within the range of 0.8≦h 4 ≦2.0.
JP3011384A 1984-02-20 1984-02-20 Optical system for coupling light source Granted JPS60173516A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3011384A JPS60173516A (en) 1984-02-20 1984-02-20 Optical system for coupling light source

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3011384A JPS60173516A (en) 1984-02-20 1984-02-20 Optical system for coupling light source

Publications (2)

Publication Number Publication Date
JPS60173516A JPS60173516A (en) 1985-09-06
JPH055081B2 true JPH055081B2 (en) 1993-01-21

Family

ID=12294721

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3011384A Granted JPS60173516A (en) 1984-02-20 1984-02-20 Optical system for coupling light source

Country Status (1)

Country Link
JP (1) JPS60173516A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3020993A2 (en) 2011-03-18 2016-05-18 Jtekt Corporation Method of manufacturing torque transmission shaft

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH065332B2 (en) * 1986-06-17 1994-01-19 日本板硝子株式会社 Optical coupler
JP2008152194A (en) * 2006-12-20 2008-07-03 Tecdia Kk Optical transceiver module

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS556354A (en) * 1978-06-30 1980-01-17 Agency Of Ind Science & Technol Refractive index distribution type lens
JPS57114101A (en) * 1980-12-30 1982-07-15 Sumitomo Electric Ind Ltd Graded lens plus combined lens using said lens and optical transmission line

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS556354A (en) * 1978-06-30 1980-01-17 Agency Of Ind Science & Technol Refractive index distribution type lens
JPS57114101A (en) * 1980-12-30 1982-07-15 Sumitomo Electric Ind Ltd Graded lens plus combined lens using said lens and optical transmission line

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3020993A2 (en) 2011-03-18 2016-05-18 Jtekt Corporation Method of manufacturing torque transmission shaft
EP3020992A2 (en) 2011-03-18 2016-05-18 Jtekt Corporation Method of manufacturing torque transmission shaft and vehicle steering apparatus

Also Published As

Publication number Publication date
JPS60173516A (en) 1985-09-06

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