JP2010122557A

JP2010122557A - Interval ring

Info

Publication number: JP2010122557A
Application number: JP2008297574A
Authority: JP
Inventors: Yasuto Kuroda; 泰斗黒田
Original assignee: Fujinon Corp
Current assignee: Fujinon Corp
Priority date: 2008-11-21
Filing date: 2008-11-21
Publication date: 2010-06-03

Abstract

<P>PROBLEM TO BE SOLVED: To reduce by half the number of interval rings prepared for the assembly of a lens barrel having a plurality of lenses. <P>SOLUTION: In the lens barrel 10, the lens 12, the interval ring 13, and the lens 14 are loaded in a lens frame 11 in that order, and then they are fixed in the lens frame 11 by a lens presser 15. The lenses 12 and 14 and the interval ring 13 are held on the same optical axis. The interval ring 13 is formed in the shape of a ring having the optical axis 16 as its center. When they are incorporated in the lens frame 11, the internal circumferential edge 13d of the front end and the internal circumferential edge 13f of the rear end are brought into contact with the lens faces 12b and 14b of the lenses 12 and 14 respectively, thereby leaving a predetermined interval between the lenses 12 and 14. By reversing the direction in which the interval ring 13 is loaded, the position where the internal circumferential edges 13d and 13f are in contact with the lens faces 12b and 14b is shifted, thereby changing the interval between the lenses 12 and 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、レンズ鏡筒に組み込まれて２枚のレンズの間隔を調整する間隔環に関するものである。 The present invention relates to an interval ring that is incorporated in a lens barrel and adjusts the interval between two lenses.

光学機器に用いられるレンズ鏡筒には複数のレンズが組み込まれたものがある。このようなレンズ鏡筒において、複数枚のレンズをレンズ鏡筒内に所定の間隔で組み込み固定して保持する方法として、例えば図６に示すように、レンズ枠５１にレンズ５２，間隔環５３及びレンズ５４を装填し、２枚のレンズ５２，５４の間に間隔環５３を挾み込んで前記２枚のレンズ５２，５４の間隔が所定の間隔となるようにレンズ枠５１内に組込んだレンズ鏡筒５０が知られている。また、下記特許文献１には、レンズ枠に形成した最大内径部よりも小さい内径寸法を有する内周面の略３分割された部分に３個の鋼球を配設して、間隔環に相当する部品として用いる方法が記載されている。
特開平０９−３１８８５８号公報 Some lens barrels used in optical equipment incorporate a plurality of lenses. In such a lens barrel, as a method of incorporating and fixing a plurality of lenses in the lens barrel at predetermined intervals, as shown in FIG. 6, for example, as shown in FIG. The lens 54 is loaded, and the interval ring 53 is sandwiched between the two lenses 52 and 54, and the lens is assembled in the lens frame 51 so that the interval between the two lenses 52 and 54 becomes a predetermined interval. A lens barrel 50 is known. Further, in Patent Document 1 below, three steel balls are arranged in a substantially three-divided portion of the inner peripheral surface having an inner diameter dimension smaller than the maximum inner diameter portion formed on the lens frame, which corresponds to a spacing ring. The method used as a part to be used is described.
JP 09-318858 A

光学レンズの間隔は数μｍの精度が必要であるため間隔環も同様の精度で加工される。しかしながら、光学レンズには当然に製造バラツキがあり、光学レンズを鏡筒に組み込んだ際にレンズ間隔を調整しなければならない。そのため、間隔環を複数枚準備して置き、間隔環を取り替えながら測定を繰り返し、ベストな状態にして固定する。鏡筒に組み込むレンズ１組１組にそれぞれ数枚の間隔環を準備しなければならず、準備する間隔環の数は相当な数となるばかりか、使用されないものは無駄になってしまう。 Since the interval between the optical lenses needs to have an accuracy of several μm, the interval ring is processed with the same accuracy. However, there is naturally a manufacturing variation in the optical lens, and the lens interval must be adjusted when the optical lens is incorporated into the lens barrel. Therefore, a plurality of spacing rings are prepared and placed, and the measurement is repeated while replacing the spacing rings to fix them in the best condition. It is necessary to prepare several interval rings for each lens to be incorporated into the lens barrel, and the number of interval rings to be prepared is not only a considerable number, but also those that are not used are wasted.

本発明は上記問題を解決するために、複数枚のレンズを有するレンズ鏡筒の組立に際して準備する間隔環の数を半減させて、無駄を少なくするとともに部品管理も省力化でき、トータルコストの削減を可能とする方法を提案するものである。 In order to solve the above problems, the present invention reduces the total cost by reducing the number of interval rings prepared for assembling a lens barrel having a plurality of lenses by half, thereby reducing waste and saving parts management. We propose a method that enables this.

本発明による間隔環は、光軸を中心とする円環状に形成され、前端側の外周エッジと内周エッジのいずれかと、後端側の外周エッジと内周エッジのいずれかを、それぞれ前後に配置されたレンズに当接させてレンズ間隔を調節する間隔環において、前端側及び後端側のそれぞれの外周エッジの相互間、または前端側及び後端側のそれぞれの内周エッジの相互間の少なくともいずれかに差をもたせたことを特徴とする。 The spacing ring according to the present invention is formed in an annular shape with the optical axis as the center, and either the outer peripheral edge or inner peripheral edge on the front end side, or the outer peripheral edge or inner peripheral edge on the rear end side, respectively In an interval ring that abuts against the arranged lens and adjusts the lens interval, between the outer peripheral edges on the front end side and the rear end side, or between the inner peripheral edges on the front end side and the rear end side, respectively. It is characterized in that at least one of them has a difference.

前記間隔環は、前端側の外周エッジと内周エッジのそれぞれの直径が、後端側の外周エッジと内周エッジのそれぞれの直径と異なるようにすると良い。前端側または後端側の少なくともいずれかにおいて、外周エッジと内周エッジの光軸方向の位置が異なるようにすると良い。 The spacing ring may be configured such that the diameters of the outer peripheral edge and the inner peripheral edge on the front end side are different from the diameters of the outer peripheral edge and the inner peripheral edge on the rear end side. The position of the outer peripheral edge and the inner peripheral edge in the optical axis direction may be different on at least one of the front end side and the rear end side.

本発明の間隔環を用いることで、レンズ鏡筒の組立時に準備する間隔環を半減することができ、無駄も半減し部品管理も半減するのでトータルコストを削減することができる。 By using the spacing ring of the present invention, the spacing ring prepared at the time of assembling the lens barrel can be halved, and waste can be halved and parts management can be halved, so that the total cost can be reduced.

図１及び図２に示すように、レンズ鏡筒１０は、レンズ枠１１にレンズ１２、間隔環１３、レンズ１４の順で装填した後にレンズ押さえ１５をレンズ枠１１のネジ部１１ｃに螺合させて、前記２枚のレンズ１２，１４及び間隔環１３をレンズ枠１１内に固定する。ここで図２の光軸１６を中心にした左右の図は、前記間隔環１３の向きを前後逆に装填すると前記２つのレンズ間隔が異なることを明瞭に示すために、前記間隔環１３の向きを前後逆にして装填したときの図を、左右に並べて図示したものである。前記２枚のレンズ１２，１４と間隔環１３は、それぞれに光軸１６と平行で光軸１６を中心とする同心円のコバ面（外周面）１２ａ，１４ａ及び外筒面１３ａを有し、レンズ枠１１に形成された光軸１６と平行で光軸を中心とする同心円の内壁１１ａ，１１ｂによって位置決めされ、同一の光軸１６上に保持される。前記間隔環１３は、前記光軸１６を中心とする円環状に形成され、前端側の外周エッジ１３ｃと後端側の外周エッジ１３ｅの直径は同じだが、前端側の内周エッジ１３ｄが後端側の内周エッジ１３ｆより大きく形成されおり、前端側の内周エッジ１３ｄ及び後端側の内周エッジ１３ｆがレンズ１２のレンズ面１２ｂ及びレンズ１４のレンズ面１４ｂのどちらかとそれぞれ当接する。 As shown in FIGS. 1 and 2, the lens barrel 10 is configured such that the lens holder 15 is screwed into the screw portion 11 c of the lens frame 11 after the lens 12, the spacing ring 13, and the lens 14 are loaded in the lens frame 11 in this order. Then, the two lenses 12 and 14 and the spacing ring 13 are fixed in the lens frame 11. Here, the left and right views around the optical axis 16 in FIG. 2 show the orientation of the spacing ring 13 in order to clearly show that the distance between the two lenses is different when the orientation of the spacing ring 13 is reversed. Fig. 2 shows the left and right sides of the figure when they are loaded in the reverse direction. The two lenses 12, 14 and the spacing ring 13 have concentric edge surfaces (outer peripheral surfaces) 12a, 14a and an outer cylindrical surface 13a that are parallel to the optical axis 16 and centered on the optical axis 16, respectively. It is positioned by concentric inner walls 11 a and 11 b that are parallel to the optical axis 16 formed in the frame 11 and centered on the optical axis, and are held on the same optical axis 16. The spacing ring 13 is formed in an annular shape centering on the optical axis 16, and the outer peripheral edge 13c on the front end side and the outer peripheral edge 13e on the rear end side have the same diameter, but the inner peripheral edge 13d on the front end side is the rear end. The inner peripheral edge 13f on the front end side and the inner peripheral edge 13f on the rear end side come into contact with either the lens surface 12b of the lens 12 or the lens surface 14b of the lens 14, respectively.

次に、上記実施形態の作用について説明する。図２の光軸１６より左側に示すように、前記内周エッジ１３ｆが前記レンズ面１２ｂと当接し前記内周エッジ１３ｄが前記レンズ面１４ｂと当接するように前記間隔環１３が装填されレンズ押さえ１５によって固定された前記レンズ鏡筒１０の光学性能を測定したときに、前記２枚のレンズ間隔が少し狭いことが判明した場合は、右側に示すように、前記間隔環１３を前後逆にして装填すると、レンズ１２とレンズ１４の間隔が広がる。前記間隔環１３を前後逆にして装填すると、前記内周エッジ１３ｄが前記レンズ面１２ｂと当接し、前記内周エッジ１３ｆが前記レンズ面１４ｂと当接するようにして、前記レンズ押さえ１５によって固定する。このとき、前記レンズ面１２ｂに当接する前記間隔環１３の内周エッジの直径が大きくなるが、前記レンズ面１２ｂは凸面であるから間隔環１３はレンズ１２側に移動する。同時に、凸面である前記レンズ面１４ｂと当接する内周エッジの直径は小さくなるので、当接する前記レンズ面１４ｂはレンズ押さえ１５側に移動する。ここで、前記レンズ面１４ｂの曲率半径は前記レンズ面１２ｂの曲率半径より小さいので、レンズ１４の移動量は間隔環１３の移動量より大きく、その結果レンズ１２とレンズ１４の間隔が広がることになる。このように、前記間隔環１３は、１個で２通りのレンズ間隔を設定することができる。 Next, the operation of the above embodiment will be described. As shown on the left side of the optical axis 16 in FIG. 2, the interval ring 13 is loaded so that the inner peripheral edge 13f contacts the lens surface 12b and the inner peripheral edge 13d contacts the lens surface 14b. When the optical performance of the lens barrel 10 fixed by 15 is measured, if it is found that the distance between the two lenses is a little narrow, as shown on the right side, the distance ring 13 is turned upside down. When loaded, the distance between the lens 12 and the lens 14 increases. When the spacing ring 13 is loaded upside down, the inner circumferential edge 13d is in contact with the lens surface 12b, and the inner circumferential edge 13f is in contact with the lens surface 14b, and is fixed by the lens presser 15. . At this time, the diameter of the inner peripheral edge of the spacing ring 13 in contact with the lens surface 12b is increased, but the spacing ring 13 moves to the lens 12 side because the lens surface 12b is a convex surface. At the same time, the diameter of the inner peripheral edge that contacts the lens surface 14b, which is a convex surface, decreases, so that the lens surface 14b that contacts the lens moves toward the lens retainer 15 side. Here, since the radius of curvature of the lens surface 14b is smaller than the radius of curvature of the lens surface 12b, the moving amount of the lens 14 is larger than the moving amount of the spacing ring 13, and as a result, the distance between the lens 12 and the lens 14 is increased. Become. As described above, one interval ring 13 can set two lens intervals.

次に別の実施形態について説明する。図３の左側に示すように、凹のレンズ面２２ｂを有するレンズ２２と、凹のレンズ面２４ｂを有するレンズ２４との間に間隔環２３が装填されている。間隔環２３は、内周は前端側から後端側までの直径は同じだが、前端側の外周エッジ２３ｃが後端側の外周エッジ２３ｅより小さく形成される。光軸１６より左側に示すように、前記外周エッジ２３ｅが前記レンズ面２２ｂと当接し前記外周エッジ２３ｃが前記レンズ面２４ｂと当接するように前記レンズ２２、間隔環２３及びレンズ２４が装填される。この状態での測定で、前記２枚のレンズ間隔が少し狭い場合は、図３の右側に示すように、前記間隔環２３を前後逆にして装填すると、前記外周エッジ２３ｃが前記レンズ面２２ｂと当接し、前記外周エッジ２３ｅが前記レンズ面２４ｂと当接するように組み直す。このとき、前記レンズ面２２ｂに当接する前記間隔環２３の外周エッジの直径は小さくなり且つ前記レンズ面１２ｂが凹面であることから間隔環２３はレンズ２２側に移動する。同時に、凹面である前記レンズ面２４ｂと当接する外周エッジの直径は大きくなるので、当接する前記レンズ面２４ｂはレンズ押さえ１５側に移動する。ここで、前記レンズ面２４ｂの曲率半径は前記レンズ面２２ｂの曲率半径より小さいので、レンズ２４の移動量は間隔環２３の移動量より大きく、その結果レンズ２２とレンズ２４の間隔が広がる。 Next, another embodiment will be described. As shown on the left side of FIG. 3, a spacing ring 23 is loaded between a lens 22 having a concave lens surface 22b and a lens 24 having a concave lens surface 24b. The interval ring 23 has the same inner diameter from the front end side to the rear end side, but the outer peripheral edge 23c on the front end side is formed smaller than the outer peripheral edge 23e on the rear end side. As shown on the left side of the optical axis 16, the lens 22, the interval ring 23, and the lens 24 are loaded such that the outer peripheral edge 23e contacts the lens surface 22b and the outer peripheral edge 23c contacts the lens surface 24b. . In the measurement in this state, when the distance between the two lenses is a little narrow, as shown on the right side of FIG. 3, when the distance ring 23 is loaded in the reverse direction, the outer peripheral edge 23c becomes the lens surface 22b. Reassembling so that the outer peripheral edge 23e contacts the lens surface 24b. At this time, the diameter of the outer peripheral edge of the spacing ring 23 that comes into contact with the lens surface 22b is reduced and the spacing of the spacing ring 23 moves toward the lens 22 because the lens surface 12b is concave. At the same time, the diameter of the outer peripheral edge that comes into contact with the concave lens surface 24b increases, so that the lens surface 24b that comes into contact moves toward the lens retainer 15 side. Here, since the radius of curvature of the lens surface 24b is smaller than the radius of curvature of the lens surface 22b, the moving amount of the lens 24 is larger than the moving amount of the spacing ring 23, and as a result, the distance between the lens 22 and the lens 24 is widened.

次に第３の実施形態について説明する。図４に示すように、凹のレンズ面３２ｂを有するレンズ３２と、凸のレンズ面３４ｂを有するレンズ３４との間に間隔環３３が装填されている。間隔環３３は、前端側の外周エッジ３３ｃが後端側の外周エッジ３３ｅより大きく形成されるとともに、前端側の内周エッジ３３ｄが後端側の内周エッジ３３ｆより大きく形成されている。光軸１６より左側に示すように、前記外周エッジ３３ｅが前記レンズ面３２ｂと当接し前記内周エッジ３３ｄが前記レンズ面３４ｂと当接するように前記間隔環３３が装填された状態で前記２枚のレンズ間隔が少し狭いときは、右側に示すように、前記間隔環３３を前後逆にして装填すると、レンズ３２とレンズ３４の間隔が広がる。前記間隔環３３を前後逆にして装填し、前記レンズ面３２ｂには前記外周エッジ３３ｃが当接し、前記レンズ面３４ｂには前記内周エッジ３３ｆが当接するように組み直す。このとき、前記レンズ面３２ｂに当接する前記間隔環３３のエッジの直径は大きくなり且つ前記レンズ面３２ｂが凹面であるから間隔環３３はレンズ３４側に移動する。同時に、凸面であるレンズ面３４ｂと当接する内周エッジの直径は大きくなるので、当接する前記レンズ面３４ｂはレンズ押さえ１５側に移動する。この場合は、前記間隔環３３、前記レンズ３４の両方ともレンズ押さえ１５側に移動して、レンズ２２とレンズ２４の間隔が広がることになる。 Next, a third embodiment will be described. As shown in FIG. 4, a spacing ring 33 is loaded between a lens 32 having a concave lens surface 32b and a lens 34 having a convex lens surface 34b. The spacing ring 33 is formed such that the outer peripheral edge 33c on the front end side is formed larger than the outer peripheral edge 33e on the rear end side, and the inner peripheral edge 33d on the front end side is formed larger than the inner peripheral edge 33f on the rear end side. As shown on the left side of the optical axis 16, the two sheets are mounted with the spacing ring 33 loaded so that the outer peripheral edge 33e is in contact with the lens surface 32b and the inner peripheral edge 33d is in contact with the lens surface 34b. When the lens interval is slightly narrow, as shown on the right side, the interval between the lens 32 and the lens 34 is widened by mounting the interval ring 33 in the reverse direction. The spacing ring 33 is loaded in the reverse direction, and is reassembled so that the outer peripheral edge 33c contacts the lens surface 32b and the inner peripheral edge 33f contacts the lens surface 34b. At this time, the diameter of the edge of the spacing ring 33 that comes into contact with the lens surface 32b becomes large and the spacing of the spacing ring 33 moves to the lens 34 side because the lens surface 32b is concave. At the same time, the diameter of the inner peripheral edge that comes into contact with the convex lens surface 34b increases, so that the lens surface 34b that comes into contact moves toward the lens presser 15 side. In this case, both the interval ring 33 and the lens 34 are moved to the lens pressing 15 side, and the interval between the lens 22 and the lens 24 is widened.

次に第４の実施形態について説明する。図５の左側に示すように、凹のレンズ面４２ｂを有するレンズ４２と、凸のレンズ面４４ｂを有するレンズ４４との間に間隔環４３が装填される。間隔環４３は、後端側の外周エッジ４３ｅと内周エッジ４３ｆの光軸方向の位置が異なるように形成され、前記外周エッジ４３ｅが前記レンズ面４２ｂと当接し、前端側の内周エッジ４３ｄが前記レンズ面４４ｂと当接するように前記間隔環４３が装填される。図の右側に示すように、前記間隔環４３を前後逆にして装填すると、レンズ４２とレンズ４４の間隔が広がる。前記間隔環４３を前後逆にして装填すると、前記レンズ面４２ｂに外周エッジ４３ｃが当接し、前記レンズ面４４ｂには前記内周エッジ４３ｆが当接する。このとき、前記レンズ面４２ｂと前記レンズ面４４ｂに当接する前記間隔環４３の外周エッジ又は内周エッジは、外周エッジ４３ｅと内周エッジ４３ｄから外周エッジ４３ｃと内周エッジ４３ｆに代わるが、内周エッジ４３ｄと外周エッジ４３ｃの光軸方向の位置は同じであるからレンズ間隔に影響しないが、外周エッジ４３ｅと内周エッジ４３ｆは光軸方向の位置が異なる。内周エッジ４３ｆは外周エッジ４３ｅに比べて突出しており、その分だけ前記レンズ面４４ｂをレンズ押さえ１５側に移動させる。これによってレンズ４２とレンズ４４の間隔が広がることになる。 Next, a fourth embodiment will be described. As shown on the left side of FIG. 5, a spacing ring 43 is loaded between a lens 42 having a concave lens surface 42b and a lens 44 having a convex lens surface 44b. The spacing ring 43 is formed such that the positions of the outer peripheral edge 43e on the rear end side and the inner peripheral edge 43f in the optical axis direction are different, the outer peripheral edge 43e abuts on the lens surface 42b, and the inner peripheral edge 43d on the front end side. The spacing ring 43 is loaded so that the lens contacts the lens surface 44b. As shown on the right side of the figure, when the spacing ring 43 is loaded in the reverse direction, the distance between the lens 42 and the lens 44 is increased. When the interval ring 43 is loaded in the reverse direction, the outer peripheral edge 43c contacts the lens surface 42b, and the inner peripheral edge 43f contacts the lens surface 44b. At this time, the outer peripheral edge or inner peripheral edge of the spacing ring 43 contacting the lens surface 42b and the lens surface 44b is replaced by the outer peripheral edge 43c and the inner peripheral edge 43f from the outer peripheral edge 43e and the inner peripheral edge 43d. Since the positions of the peripheral edge 43d and the outer peripheral edge 43c in the optical axis direction are the same, the lens interval is not affected, but the outer peripheral edge 43e and the inner peripheral edge 43f have different positions in the optical axis direction. The inner peripheral edge 43f protrudes compared to the outer peripheral edge 43e, and the lens surface 44b is moved toward the lens presser 15 by that amount. As a result, the distance between the lens 42 and the lens 44 is increased.

前記実施形態は、２枚のレンズの間隔を広げる場合について説明したが、逆の使い方をすれば間隔を狭くする場合にも適用可能であることは言うまでもない。また、外周エッジ及び内周エッジは、９０度を意味するものではなく、レンズ面に対して円環状に高精度で当接するのであれば、９０度以外の角度を持ったものでも差し支えない。 In the above embodiment, the case where the distance between the two lenses is increased has been described. Needless to say, however, the present invention can also be applied to the case where the distance is narrowed if the usage is reversed. Further, the outer peripheral edge and the inner peripheral edge do not mean 90 degrees, and may have an angle other than 90 degrees as long as they contact the lens surface in an annular shape with high accuracy.

本発明によるレンズ鏡筒の分解図である。1 is an exploded view of a lens barrel according to the present invention. FIG. 本発明によるレンズ鏡筒を示し、間隔環の装填方向を逆にしたときの断面を光軸を挟んだ左右に示したものである。The lens barrel by this invention is shown, and the cross section when the loading direction of a space | interval ring is reversed is shown on either side of the optical axis. 別の実施形態を図２と同様に示した断面図である。It is sectional drawing which showed another embodiment similarly to FIG. 第３の実施形態を図２と同様に示した断面図である。It is sectional drawing which showed 3rd Embodiment similarly to FIG. 第４の実施形態を図２と同様に示した断面図である。It is sectional drawing which showed 4th Embodiment similarly to FIG. 間隔環を用いたレンズ鏡筒の従来例を示す断面図である。It is sectional drawing which shows the prior art example of the lens-barrel using a space ring.

Explanation of symbols

１０レンズ鏡筒
１１レンズ枠
１２，１４，２２，２４，３２，３４，４２，４４レンズ
１２ｂ，１４ｂ，２２ｂ，２４ｂ，３２ｂ，３４ｂ，４２ｂ，４４ｂレンズ面
１３，２３，３３，４３間隔環
１３ｃ，２３ｃ，３３ｃ，４３ｃ外周エッジ（前端側）
１３ｄ，２３ｄ，３３ｄ，４３ｄ内周エッジ（前端側）
１３ｅ，２３ｅ，３３ｅ，４３ｅ外周エッジ（後端側）
１３ｆ，２３ｆ，３３ｆ，４３ｆ内周エッジ（後端側）
１５レンズ押さえ
１６光軸
10 Lens barrel 11 Lens frame 12, 14, 22, 24, 32, 34, 42, 44 Lens 12b, 14b, 22b, 24b, 32b, 34b, 42b, 44b Lens surface 13, 23, 33, 43 Space ring 13c , 23c, 33c, 43c Outer peripheral edge (front end side)
13d, 23d, 33d, 43d Inner peripheral edge (front end side)
13e, 23e, 33e, 43e Outer edge (rear end side)
13f, 23f, 33f, 43f Inner peripheral edge (rear end side)
15 Lens holder 16 Optical axis

Claims

It is formed in an annular shape centered on the optical axis, and either the outer peripheral edge or inner peripheral edge on the front end side, or the outer peripheral edge or inner peripheral edge on the rear end side is brought into contact with the lenses arranged at the front and rear, respectively. In the interval ring to adjust the lens interval,
A spacing ring characterized in that a dimensional difference is provided at least either between the outer peripheral edges on the front end side and the rear end side or between the inner peripheral edges on the front end side and the rear end side.

The spacing ring according to claim 1, wherein the diameters of the outer peripheral edge and the inner peripheral edge on the front end side are different from the diameters of the outer peripheral edge and the inner peripheral edge on the rear end side.

The spacing ring according to claim 1 or 2, wherein the position of the outer peripheral edge and the inner peripheral edge in the optical axis direction is different on at least one of the front end side and the rear end side.