JP4465876B2

JP4465876B2 - Compound lens, method for assembling compound lens, fixed diaphragm and molding method

Info

Publication number: JP4465876B2
Application number: JP2000396042A
Authority: JP
Inventors: 晃熊野; 宏人荻山; 藤雄金井; 達郎牧井
Original assignee: Sony Corp
Current assignee: Sony Corp
Priority date: 2000-12-26
Filing date: 2000-12-26
Publication date: 2010-05-26
Anticipated expiration: 2020-12-26
Also published as: JP2002196211A

Description

【０００１】
【発明の属する技術分野】
本発明は、複数のレンズの間に固定絞りを配置させて一体化した複合レンズと、この複合レンズの組立方法、この複合レンズに用いる固定絞りおよびこの固定絞りの成形方法に関する。
【０００２】
【従来の技術】
２枚のレンズの間に光線束を通過させる開口を備え不要な光線束を遮断する固定絞りを配置させた複合レンズの光学系では、レンズと固定絞りとの位置決め精度が重要である。
レンズの光軸と固定絞りの開口の中心軸とのずれおよび光軸方向の位置ずれが存在すると、複合レンズの結像にされる画像に、シェーディングが発生する可能性があり、光学性能が低下する。
また、結像に寄与しない不要な光線束を効果的に遮り、フレアやゴーストの発生を抑制するためには、２枚のレンズの間に２枚の固定絞りを配置することが一般的である。
一方、上記のような２枚のレンズの間に固定絞りを配置した複合レンズの光学系を構成するには、たとえば、レンズ鏡筒や移動枠にそれぞれ別部品として用意されたレンズや固定絞りを組付ける。
【０００３】
【発明が解決しようとする課題】
しかしながら、別部品として用意されたレンズや固定絞りをレンズ鏡筒や移動枠に組付けることによって複合レンズの光学系を構成すると、組立精度を確保するのが難しく、所望の光学性能を得るために、レンズおよび固定絞り間の調芯工程等が増加し、製造コストが嵩むという不利益が存在する。
特に、２枚のレンズの間に２枚の固定絞りを配置する複合レンズの光学系では、２枚の固定絞りの中心軸と２枚のレンズの光軸を調芯する必要があり、組立精度を確保することがさらに難しい。
【０００４】
本発明は、上述の問題に鑑みて成されたものであって、レンズ間に固定絞りを配置した複合レンズにおいて、レンズと固定絞り間、レンズ間および固定絞り間の位置精度が向上した複合レンズおよび位置精度を向上できかつ複合レンズの組立が容易である組立方法を提供することを目的とする。
また、本発明は、上記の複合レンズに用いるのに好ましい固定絞りおよびこの固定絞りの成形方法を提供することを目的とする。
【０００５】
【課題を解決するための手段】
本発明の複合レンズは、第１および第２のレンズと、前記第１および第２のレンズ間に配置され、光線束を通過させる開口孔を中心に備え、前記第１および第２のレンズを透過する光線束のうち不要な光線束を遮断する固定絞りと、を有し、前記第１および第２のレンズと前記固定絞りとが一体的に組み立てられた複合レンズであって、前記第１および第２のレンズは、光軸方向において互いに当接し、光軸方向の相対位置を規定する当接部と、互いに嵌合し当該第１および第２のレンズの光軸を合致させるテーパ部とをそれぞれ備え、前記固定絞りは、前記第１のレンズのテーパ部の内周に嵌合し、当該第１のレンズに対する光軸方向の相対位置を規定し、かつ、前記開口孔の中心軸と光軸とを合致させるテーパ部を備える。
【０００６】
前記第１レンズ、前記第２のレンズおよび前記固定絞りは、接着剤によって互いに接合されている。
【０００７】
好適には、前記固定絞りのテーパ部の背面部と、前記第２のレンズのテーパ部の一部と、前記背面部に対向する前記第１のレンズの端面の一部とによって、前記接着剤を収容する接着剤収容空間が形成されている。
【０００８】
好適には、前記第１および第２のレンズおよび前記固定絞りは、樹脂で形成されている。
【０００９】
前記第１および第２のレンズのテーパ部は、当該第１および第２のレンズを成形金型によって成形した際に離型を容易化するためのテーパ部である。
【００１０】
前記固定絞りは、形状が同一であり、前記開口孔が互いに合致するように重ね合わせて配置された第１および第２の固定絞りから構成される。
【００１１】
前記第１および第２の固定絞りの開口孔は、内周面が一方の開口端から他方の開口端に向かって拡径した傾斜面となっており、拡径した側の端面が接するように重ね合わされており、前記各テーパ部が互いに離反する向きに配置されている。
【００１２】
好適には、前記第１および第２の固定絞りは、互いに嵌合して当該第１および第２の固定絞り部の相対位置を規定する嵌合部を備えている。
【００１３】
さらに好適には、前記嵌合部は、前記固定絞りの一端面から突出する突出部と、この突出部が嵌合挿入される貫通孔とで構成される。
【００１４】
前記固定絞りの開口孔は、前記第１のレンズ側の開口端および前記第２のレンズ側の開口端においてそれぞれ不要な光線束を遮断可能な形状となっている。
【００１５】
好適には、前記固定絞りの開口孔は、内周面が両開口端に対して拡径した凹面となっている。
【００１６】
さらに好適には、前記固定絞りは、光軸方向の両側に互いに離反する前記テーパ部を備える。
【００１７】
本発明の複合レンズの組立方法は、第１および第２のレンズと、前記第１および第２のレンズ間に配置され、光線束を通過させる開口孔を中心に備え、前記第１および第２のレンズを透過する光線束のうち不要な光線束を遮断する固定絞りと、を有し、前記第１および第２のレンズと前記固定絞りとが一体的に組み立てられた複合レンズの組立方法であって、前記第１のレンズに光軸に沿って形成されたテーパ部の内周に前記固定絞りに形成された前記開口孔の中心軸に沿って形成されたテーパ部の外周を嵌合させて、前記第１のレンズに対する光軸方向の相対位置を決定し、かつ、前記開口孔の中心軸と光軸とを合致させ、前記第１のレンズのテーパ部の内周に前記第２のレンズに光軸に沿って形成されたテーパ部の外周をさらに嵌合させて、当該第１のレンズと第２のレンズの光軸を合致させ、かつ、前記第１および第２のレンズを光軸方向において当接させて、当該第１のレンズと第２のレンズの光軸方向の相対位置を決定する。
【００１８】
本発明の複合レンズの組立方法は、互いに同一形状の第１および第２の固定絞りを用意し、前記各固定絞りの前記開口孔が互いに合致し、かつ、互いの前記テーパ部が離反する向きに重ね合わせ、前記第１および第２の固定絞りの一方のテーパ部を前記第１のレンズのテーパ部に嵌合させ、前記第１のレンズのテーパ部の内周に前記第２のレンズのテーパ部をさらに嵌合させ、かつ、当該第１および第２のレンズを当接させる。
【００１９】
本発明の複合レンズの組立方法は、同一の成形金型で一体成形され、部分的に互いに連結された同一形状の第１および第２の固定絞りを用意し、前記第１および第２の固定絞りの連結部を折り曲げて前記開口孔が互いに合致し、かつ、互いのテーパ部が離反する向きに重ね合わせる。
【００２０】
本発明の複合レンズの組立方法は、前記連結部を折り曲げて重ね合わせた際に互いに嵌合して相対位置を規定する嵌合部をさらに備える前記第１および第２の固定絞りを用意し、前記第１および第２の固定絞りの連結部を折り曲げて前記嵌合部を嵌合させることによって当該第１および第２の固定絞りを重ね合わせる。
【００２１】
本発明の複合レンズの組立方法は、前記第１のレンズのテーパ部に前記固定絞りのテーパ部を嵌合させた後に、前記第１のレンズのテーパ部の一部と前記固定絞り部材のテーパ部の背面部とによって形成される凹部に接着剤を塗布し、前記第１のレンズに前記第２のレンズを嵌合および当接させ、前記第１のレンズのテーパ部の一部と、前記固定絞りのテーパ部の背面部と、当該背面部に対向する前記第２のレンズの端面の一部とを前記接着剤によって接合する。
【００２２】
本発明の複合レンズの組立方法は、前記第１のレンズ側の開口端および前記第２のレンズ側の開口端においてそれぞれ不要な光線束を遮断可能な形状の開口孔を備え、かつ、光軸方向の両側に互いに離反する前記テーパ部をもつ固定絞りを用意し、前記固定絞りのテーパ部の一方を前記第１のレンズのテーパ部に嵌合させる。
【００２３】
本発明の固定絞りは、第１および第２のレンズ間に配置され、光線束を通過させる開口孔を中心に備え、前記第１および第２のレンズを透過する光線束のうち不要な光線束を遮断する固定絞りであって、固定絞りの開口孔は、内周面が両開口端に対して拡径した凹面となっており、前記各開口端において不要な光線束を遮断可能となっている。
【００２４】
好適には、前記固定絞りは、樹脂で一体成形されている。
【００２５】
本発明の固定絞りの成形方法は、第１および第２のレンズ間に配置され、光線束を通過させる開口孔を中心に備え、前記第１および第２のレンズを透過する光線束のうち不要な光線束を遮断する固定絞りを樹脂成形する固定絞りの成形方法であって、前記固定絞りの開口孔は、内周面が両開口端に対して拡径した凹面となっており、前記各開口端において不要な光線束を遮断可能となっており、前記固定絞りを金型を用いて成形する際に、金型のキャビティ内に設置される前記開口孔を成形するための開口孔成形用ピンに前記凹面に合致した拡径部を設け、前記キャビティ内に樹脂を充填し、当該樹脂が凝固したのちに、成形された固定絞りから固化した樹脂による抵抗に抗して前記開口孔成形用ピンを引き抜いて前記開口孔を成形する。
【００２６】
本発明では、第１のレンズのテーパ部に固定絞りのテーパ部を嵌合させる。これにより、第１のレンズの光軸と固定絞りの開口孔の中心軸とが合致するとともに、光軸方向の相対位置が決定される。この状態から第１のレンズのテーパ部に第２のレンズのテーパ部を嵌合させるとともに、互いの当接部を当接される。
これにより、第１のレンズと第２のレンズの光軸が合致するとともに、光軸方向の相対位置が決定される。
このように、本発明では、第１のレンズへの固定絞りの組付けおよび第１のレンズへの第２のレンズの組付けによって、第１のレンズ、第２のレンズの光軸および固定絞りの中心軸の位置合わせと、第１のレンズ、第２のレンズおよび固定絞りの光軸方向の相対位置決めが同時に行われる。
【００２７】
【発明の実施の形態】
以下、本発明の実施の形態について図面を参照して説明する。
第１の実施形態
図１は本発明の第１の実施形態に係る複合レンズの構造を示す断面図であり、図２は図１に示す複合レンズの破断斜視図である。
図１に示す複合レンズ１は、第１レンズ２と、第２レンズ１０と、固定絞り２０とを備えている。
【００２８】
第１レンズ２は、たとえば、透明なプラスチック等の樹脂材料を金型を用いて射出成形することによって得られる。
第１レンズ２は、光軸方向の一端面側に球面状のレンズ面２ａと、第２レンズ１０と対向する他端面側に平面状のレンズ面２ｃとを備えている。この第１レンズ２は、レンズ面２ａおよび２ｃの外周に、第１レンズ２を第２レンズ１０および固定絞り２０と一体的に組み立てるため、および、第１レンズ２をレンズ鏡筒に組み込むための非レンズ部２ｂを備えている。
【００２９】
第１レンズ２の非レンズ部２ｂとレンズ面２ａとの境界には、円周方向に沿って溝部２ｔが形成されている。溝部２ｔは、金型から第１レンズ２が離型しやすいように、抜きテーパをもっている。
【００３０】
非レンズ部２ｂのレンズ面２ｃ側には、光軸に対して所定の角度、たとえば、４５度で傾斜するテーパ面２ｄが形成されている。このテーパ面２ｄの外周には、光軸に直交する当接面２ｅが形成されている。テーパ面２ｄおよび当接面２ｅは、第１レンズ２を成形する金型におけるレンズ面２ａ，２ｃの型面と同様に高精度に加工された型面により成形される。
テーパ面２ｄは、後述するように、固定絞り２０および第２レンズ１０が嵌合する。さらに、このテーパ面２ｄは金型からの第１レンズ２の離型を容易にするために傾斜している。
【００３１】
第２レンズ１０は、たとえば、透明なプラスチック等の樹脂材料を金型を用いて射出成形することによって得られる。
第２レンズ１０は、光軸方向の一端面側に球面状のレンズ面１０ａと、第１レンズ２と対向する他端面側に球面状のレンズ面１０ｃとを備えたメニスカスレンズである。
この第２レンズ１０は、レンズ面１０ａおよび１０ｃの外周に、第２レンズ１０を第１レンズ２および固定絞り２０と一体的に組み立てるため、および、第２レンズ１０をレンズ鏡筒に組み込むための非レンズ部１０ｂを備えている。
【００３２】
第２レンズ１０の非レンズ部１０ｂとレンズ面１０ａとの境界には、円周方向に沿って溝部１０ｔが形成されている。溝部１０ｔは、金型から第２レンズ１０が離型しやすいように、抜きテーパをもっている。
【００３３】
第２レンズ１０のレンズ面１０ｃの外周には、固定絞り２０に対向する端面１０ｆが形成され、端面１０ｆの外周には、第１レンズ２のテーパ面２ｄと嵌合するテーパ面１０ｄが形成されている。このテーパ面１０ｄは、第１レンズ２のテーパ面２ｄと同じ角度で光軸に対して傾斜している。
第１レンズ２のテーパ面２ｄと第２レンズ１０のテーパ面１０ｄとは、嵌合することにより、第１レンズ２および第２レンズ１０の光軸が合致する。
【００３４】
第２レンズ１０のテーパ面１０ｄの外周には、光軸に直交し、第１レンズ２の当接面２ｅに当接する当接面１０ｅが形成されている。第１レンズ２の当接面２ｅと第２レンズ１０の当接面１０ｅとが当接することにより、第１レンズ２および第２レンズ１０の光軸方向の相対位置が決定される。
なお、第１レンズ２の当接面２ｅと第２レンズ１０の当接面１０ｅとが当接した状態において、第１レンズ２のテーパ面２ｄと第２レンズ１０のテーパ面１０ｄとの間には、複合レンズ１に要求される光学性能を満足させる範囲でクリアランスをもつように形成されている。
また、テーパ面１０ｄおよび当接面１０ｅは、第２レンズ１０を成形する金型におけるレンズ面１０ａ，１０ｃの型面と同様に高精度に加工された型面により成形される。
【００３５】
固定絞り２０は、２枚の同じ形状の固定絞り部材２１を重ね合わせて構成されている。
これら２枚の固定絞り部材２１は、たとえば、ポリカーボネートにガラスを添加した黒色の樹脂から成形されている。
図３は、固定絞り部材２１の構造を示す図であって、（ａ）は平面図であり、（ｂ）は（ａ）のＡ−Ａ線方向の断面図である。
図３に示すように、固定絞り部材２１は、円板状の部材からなり、中心部に開口孔２１ａを備えている。この開口孔２１ａは、図３（ｂ）に示すように、内周面の直径が一方端面２１ｄ側の開口端から他方端面２１ｆの開口端に向けて拡径する傾斜面２１ｃとなっている。
【００３６】
固定絞り部材２１の外周には、第１レンズ２のテーパ面２ｄの内周に嵌合する、テーパ面２ｄと同じ角度で開口孔２１ａの中心軸に対して傾斜したテーパ面２１ｂが形成されている。この固定絞り部材２１のテーパ面２１ｂが第１レンズ２のテーパ面２ｄに嵌合することにより、開口孔２１ａの中心軸と第１レンズ２の光軸が合致する。さらに、固定絞り部材２１と第１レンズ２との光軸方向の相対位置が決定される。
【００３７】
図１に示したように、上記構成の２枚の固定絞り部材２１は、開口孔２１ａの位置が一致するように重ね合わされている。また、開口孔２１ａが拡径した側の端面２１ｆ同士が接するように重ね合わされる。この状態において、各固定絞り部材２１のテーパ面２１ｂが互いに離反する向きに配置される。
２枚の固定絞り部材２１は、開口孔２１ａに傾斜面２１ｃが形成されていることから、各開口孔２１ａの小径側の開口端で光線束を遮断可能となっている。
２枚の固定絞り部材２１を重ね合わせた固定絞り２０の開口孔は、内周面が凹状となり、この内周面で反射した不要な光を遮断可能となっている。
【００３８】
図１に示したように、２枚の固定絞り部材２１のうち、一方の固定絞り部材２１のテーパ面２１ｂは第１レンズ２のテーパ面２ｄに嵌合する。
一方、他方の固定絞り部材２１のテーパ面２１ｂは、第１レンズ２のテーパ面２ｄに嵌合するテーパ面２１ｂに背面側に位置している。
この他方の固定絞り部材２１のテーパ面２１ｂと、第２レンズ１０の端面１０ｆの一部および第１レンズ２のテーパ面２ｄとの間には、接着剤Ｇを収容する空間が形成されている。この空間に充填された接着剤Ｇにより、第１レンズ２、第２レンズ１０および固定絞り２０は互いに接合されている。
【００３９】
また、第２レンズ１０の端面１０ｆと他方の固定絞り部材２１の端面との間には、所定のクリアランスが形成される。このクリアランスは、第１レンズ２の当接部２ｅと第２レンズ１０の当接部１０ｅとの当接による第１レンズ２および第２レンズ１０の光軸方向の位置決めを妨げないために設けられている。
また、このクリアランスは、固定絞り部材２１の位置ずれ量が複合レンズ１の光学性能に影響を与えない範囲に規定されている。
【００４０】
次に、上記構成の複合レンズ１の組立方法の一例について図４〜図９を参照して説明する。
まず、図４に示すように、第１レンズ２および固定絞り部材２１を用意し、固定絞り部材２１のテーパ面２１ｂを第１レンズ２のテーパ面２ｄに向けて嵌合させる。
固定絞り部材２１のテーパ面２１ｂを第１レンズ２のテーパ面２ｄに嵌合させることにより、図５に示すように、第１レンズ２のレンズ面２ｃの外周の端面２ｆと固定絞り部材２１の端面２１ｄとの間には、所定量の隙間が正確に形成される。この隙間は、複合レンズ１の光学性能を左右する。
また、固定絞り部材２１のテーパ面２１ｂを第１レンズ２のテーパ面２ｄに嵌合させることにより、固定絞り部材２１の開口孔２１ａの中心軸と第１レンズ２の光軸が合致する。
【００４１】
次いで、図６に示すように、第１レンズ２に嵌合した状態にある固定絞り部材２１に対して、さらに、固定絞り部材２１を用意する。
新たに用意した固定絞り部材２１を第１レンズ２に嵌合した状態にある固定絞り部材２１上に重ね合わせ、図７に示す状態にする。
このとき、固定絞り部材２１の端面２１ｆ同士が対向するように重ね合わせる。すなわち、同一形状の２枚の固定絞り部材２１を表裏を逆にして重ね合わせる。
また、２枚の固定絞り部材２１の開口孔２１ａの中心軸が一致するように、２枚の固定絞り部材２１間の調芯作業も必要である。
【００４２】
次いで、図８に示すように、重ね合わせた２枚の固定絞り部材２１のうち、第１レンズ２のテーパ面２ｄに嵌合していない固定絞り部材２１のテーパ面２１ｂと第１レンズ２のテーパ面２ｄとの間に形成される凹部に、たとえば、ディスペンサーＤを用いて接着剤Ｇを適量塗布する。
この接着剤Ｇの塗布は、固定絞り部材２１のテーパ面２１ｂと第１レンズ２のテーパ面２ｄとの間に形成される凹部の全周に塗布してもよいが、接合に必要不可欠な最小限の箇所に塗布することが好ましい。接着剤Ｇが複合レンズ１の光学性能に影響を及ぼすのを避けるためである。
【００４３】
次いで、図９に示すように、接着剤Ｇが塗布された状態の第１レンズ２に対して、第２レンズ１０を組付ける。
第１レンズ２に対して第２レンズ１０を組付けると、第１レンズ２のテーパ面２ｄに第２レンズ１０のテーパ面１０ｄが嵌合するとともに、第１レンズ２の当接面２ｅに第２レンズ１０の当接面１０ｅが当接する。これにより、第１レンズ２と第２レンズ１０の光軸が合致し、かつ、光軸方向の相対位置が決定される。
【００４４】
また、第２レンズ１０の端面１０ｆの一部は、固定絞り部材２１のテーパ面２１ｂと第１レンズ２のテーパ面２ｄとの間に形成される凹部に塗布された接着剤Ｇに接触する。接着剤Ｇが固化すると、第２レンズ１０の端面１０ｆの一部と、固定絞り部材２１のテーパ面２１ｂの一部と、第１レンズ２のテーパ面２ｄの一部とが接合される。
これにより、複合レンズ１の組み立てが完了する。
【００４５】
以上のように、本実施形態の複合レンズ１では、第１レンズ２および第２レンズ１０と２枚の固定絞り部材２１からなる固定絞り２０とを一体化し、一つの部品とすることにより、複合レンズ１を、たとえば、レンズ鏡筒に組付ける際に、第１レンズ２、第２レンズ１０および固定絞り２０の間の位置合わせの必要がなくなる。
また、本実施形態の複合レンズ１では、金型からの第１のレンズ２の離型性を良くするためのテーパ面２ｄに固定絞り２０を嵌合させ、同じくテーパ面２ｄにに第２のレンズ１０のテーパ面１０ｄを嵌合させることから、テーパ面２ｄおよびテーパ面１０ｄの金型による形成が容易である。
【００４６】
また、本実施形態の複合レンズ１の組立方法によれば、第１レンズ２に固定絞り部材２１を嵌合させ、さらに第１レンズ２に第２レンズ１０を嵌合させるだけで高い精度の位置決めがなされ、位置合わせおよび調芯作業が不要になり、組み立て工程を簡素化できる。
また、本実施形態の複合レンズ１の組立方法によれば、２枚の固定絞り部材２１を第１レンズ２に組み込んだのち、接着剤Ｇを塗布するだけで、第１レンズ２、２枚の固定絞り部材２１および第２レンズ１０の接合を同時に行うことができ、組み立て工程をさらに簡略化することができる。
【００４７】
なお、上述実施形態では、２枚の固定絞り部材２１を重ね合わせる際に、固定絞り部材２１の間の中心軸を正確に位置合わせする必要がある。
固定絞り部材の間の位置合わせ作業を簡略化できる構造の固定絞りについて説明する。
図１０は、固定絞りの他の例を示す図であって、（ａ）は平面図であり、（ｂ）は（ａ）のＢ−Ｂ線方向の断面図である。なお、図１０において、上記の固定絞り２０と同一構成部分については同一の符号を付している。
【００４８】
図１０に示す固定絞り３０は、２枚の固定絞り部材２１を備えており、これら固定絞り部材２１の外周が部分的に連結部２２によって連結されている。
各固定絞り部材２１は、基本形状が円板状であり、連結部２２が形成された外周の一部がそれぞれ平坦化されたフラット部２１ｄとなっている。連結部２２は、各固定絞り部材２１の厚さに比べて薄肉化されている。
各固定絞り部材２１の中心部には、開口孔２１ａが形成されており、開口孔２１ａの内周面は傾斜面２１ｃとなっている。
各固定絞り部材２１の外周には、第１レンズ２のテーパ面２ｄと嵌合するテーパ面２１ｂが形成されている。
【００４９】
２枚の固定絞り部材２１のうち、一方の固定絞り部材２１の端面２１ｆ上に嵌合用突起２１ｈが形成されており、他方の固定絞り部材２１には嵌合用突起２１ｈが嵌合する嵌合孔２１ｉが形成されている。
嵌合用突起２１ｈが形成されている端面２１ｆは、開口孔２１ａの拡径側の開口端が位置する端面である。
【００５０】
上記の連結された２枚の固定絞り部材２１からなる固定絞り３０は、金型によって一体成形されている。
成形材料としは、たとえば、ポリアセタール等の樹脂材料を用いる。固定絞り３０の材料にポリアセタールをもちいれば、比較的柔軟な材料であるので、連結部２２を折り曲げた際に、連結部２２が折損することがない。
【００５１】
上記構成の固定絞り３０は、第１レンズ２に組み込まれる前に図１１に示すように、連結部２２を折り曲げて重ね合わされる。
このとき、固定絞り部材２１の端面２１ｆが対向する向きに折り曲げ、嵌合突起２１ｈに嵌合孔２１ｉを嵌合させる。
【００５２】
固定絞り部材２１を重ね合わせると、図１２に示すように、各固定絞り部材２１の開口孔２１ａの中心軸が合致する。また、固定絞り部材２１のテーパ面２１ｂが互いに離反する向きに重ね合わさる。
さらに、固定絞り部材２１にフラット部２１ｇをそれぞれ形成していることから、折り曲げられた連結部２２は、固定絞り部材２１の外径内に収まっている。
【００５３】
このようにして固定絞り部材２１が重ね合わせられた固定絞り３０の、２枚の固定絞り部材２１のうち、一方のテーパ面２１ｂが第１レンズ２のテーパ面２ｄに嵌合する。
また、連結部２２が存在した状態で、固定絞り３０は第１レンズ２のテーパ面２ｄに組付けられる。
【００５４】
以上のように、基本形状が同一の２枚の固定絞り部材２１が連結部２２によって連結された固定絞り３０を一体成形し、２枚の固定絞り部材２１を折り合わせることにより、２枚の固定絞り部材２１間の調芯作業が必要なくなる。
また、固定絞り部材２１の一端面２１ｆに嵌合突起２１ｈを形成しているため、２枚の固定絞り部材２１を重ね合わせる際の向きを間違えることがない。
また、固定絞り３０は、折り合わせた状態で表側と裏側の形状が同一であるため、第１レンズ２に固定絞り３０を組付ける際に、表裏を意識する必要がない。
【００５５】
第２の実施形態
図１３は、本発明の第２の実施形態に係る複合レンズの構造を示す断面図である。なお、上述した第１の実施形態に係る複合レンズ１と同一の構成部分については同一の符号を付している。
図１３に示す複合レンズ１００は、第１レンズ２と、第２レンズ１０と、固定絞り４０とを備えている。第１レンズ２および第２レンズ１０は、上述した第１の実施形態に係る複合レンズ１と同一構成である。
第１レンズ２および第２レンズ１０の間に固定絞り４０が配置されている。固定絞り４０は、上述した第１の実施形態に係る固定絞り２０または３０と同じ配置となっている。
【００５６】
図１４は、固定絞り４０の構造を示す図であって、（ａ）は平面図であり、（ｂ）は（ａ）のＣ−Ｃ線方向の断面図である。
図１４に示すように、固定絞り４０は、円板状の部材から形成され、中心部に光線束が通過する開口孔４０ａを備えている。
固定絞り４０の外周には、光軸方向の両側に互いに離反する向きに形成されたテーパ面４０ｂおよび４０ｃが形成されている。テーパ面４０ｂおよび４０ｃは、第１レンズ２のテーパ面２ｄと同じ角度で開口孔４０ａの中心軸に対して傾斜している。
この固定絞り４０のテーパ面４０ｂまたは４０ｃが第１レンズ２のテーパ面２ｄに嵌合することにより、開口孔４０ａの中心軸と第１レンズ２の光軸が合致する。さらに、固定絞り４０と第１レンズ２との光軸方向の相対位置が決定される。
【００５７】
固定絞り４０の開口孔４０ａは、両方の開口端４０ｅおよび４０ｆにおいてそれぞれ不要な光線束を遮断可能な形状となっている。すなわち、開口孔４０ａは２枚の絞りを配置したのと同様の機能を果たす。
具体的には、固定絞り４０の開口孔４０ａは、内周面が両開口端４０ｅおよび４０ｆに対して拡径した凹面４０ｄとなっている。
このような形状に固定絞り４０の開口孔４０ａを形成することにより、一方の開口端４０ｅを通過して凹面４０ｄで反射した光が他方の開口端４０ｆで遮断され、結像に寄与しない不要な光線束を効果的に遮り、フレアやゴーストの発生を抑制することができる。
【００５８】
次に、固定絞り４０の成形方法について説明する。
図１５は、固定絞り４０を一体成形するための金型の構成を示す図である。
固定絞り４０を一体成形する金型には、固定絞り４０の一方面側を成形する型面３００ａを備える固定金型３００と、固定絞り４０の他方面側を成形する型面２００ａを備える可動金型２００とを用いる。
また、可動金型２００と固定金型３００との間に形成されるキャビティＣ内には、先端部に固定絞り４０の開口孔４０ａの形状に合致した拡径部４００ａを備える開口孔成形用ピン４００を設置する。この開口孔成形用ピン４００は、固定金型３００に形成された挿入孔３００ｂに挿入され、拡径部４００ａのみがキャビティＣ内に置かれる。
固定金型３００には、成形品を固定金型３００から引き離すための押出ピン５００が型面３００ａから突出可能に設けられている。
【００５９】
図１５に示すように、可動金型２００と固定金型３００と型締した状態において、キャビティＣに連通する図示しないゲートから樹脂を充填する。
使用する樹脂材料としては、たとえば、ポリアセタール等の樹脂材料を用いる。
【００６０】
図１６に示すように、キャビティＣ内に樹脂を充填し、樹脂が固化すると、固定絞り４０が成形される。
固定絞り４０が成形されたら、図１７に示すように、可動金型２００を固定金型３００に対して開きながら、押出ピン５００によって固定絞り４０を押し出すことにより、固定金型３００から引き離す。
【００６１】
このとき、固定絞り４０の開口孔４０ａの内周が凹面４０ｄとなっていることから、開口孔成形用ピン４００の拡径部４００ａから固定絞り４０が抜けにくいが、無理やり引き抜く。
固定絞り４０を成形する樹脂としてポリアセタール等の比較的柔軟な樹脂を使用することにより、開口孔成形用ピン４００の拡径部４００ａから固定絞り４０を無理に引き抜いても固定絞り４０が破損するのを防止することができる。
【００６２】
上記の成形方法によって成形された固定絞り４０は、上述した組立方法と同様に、テーパ面４０ｂ，４０ｃの一方が第１レンズ２のテーパ面２ｄに嵌合され、テーパ面４０ｂ，４０ｃの他方と第１レンズ２のテーパ面２ｄの一部で形成される凹部に接着剤が塗布される。
この状態から、第２レンズ１０が第１レンズ２に組付けられ、接着剤によって第１レンズ２、固定絞り４０および第２レンズ１０が接合され、複合レンズ１００が完成する。
【００６３】
以上のように、本実施形態によれば、２つの絞り機能を有する固定絞り４０の開口孔４０ａを無理抜きにより成形することで、２枚の固定絞り部材をそれぞれ成形する必要がなくなる。また、２枚の固定絞り部材を重ね合わせる工程も不要となる。
【００６４】
種々の実施形態を挙げて本発明を説明したが、本発明は上述した実施形態に限定されない。
上述した第１および第２の実施形態においては、絞りのための開口端が２つある場合について説明したが、１枚の固定絞りの場合にも本発明は適用可能である。
【００６５】
また、上述した実施形態では、固定絞り部材２１のテーパ面２１ｂと第２レンズ１０の端面１０ｆの一部および第１レンズ２のテーパ面２ｄとの間に接着剤Ｇを収容する空間が形成し、この空間に接着剤Ｇを充填することにより、第１レンズ２、第２レンズ１０および固定絞り２０を互いに接合する構成としたが、本発明はこれに限定されない。
たとえば、図１８に示すように、第１レンズ２の当接面２ｅの外周は、金型からの離型を容易にする抜きテーパ部となっており、この抜きテーパ部と第２レンズ１０の当接面１０ｅとの間には凹部が形成される。このため、この凹部に接着剤Ｇを充填することにより、第１レンズ２と第２レンズ１０とを接合することも可能である。
【００６６】
【発明の効果】
本発明によれば、レンズ間に固定絞りを配置した複合レンズにおいて、レンズと固定絞り間、レンズ間および固定絞り間の位置精度を向上させることができるまた、本発明によれば、２枚のレンズの間および２枚の固定絞り部材の間の調芯工程を無くすことができる。
また、本発明による複合レンズを一つの部品として取り扱うことにより、取り回しやすくなり、レンズ鏡筒等への組付けも簡単になる。
また、２枚の固定絞りを組み込むことにより、フレア、ゴーストを効果的に抑制することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施形態に係る複合レンズの構造を示す断面図である。
【図２】図１に示す複合レンズの破断斜視図である
【図３】固定絞り２１の構造を示す図である。
【図４】複合レンズ１の組立手順を説明するための図である。
【図５】図４に続く複合レンズ１の組立手順を説明するための図である。
【図６】図５に続く複合レンズ１の組立手順を説明するための図である。
【図７】図６に続く複合レンズ１の組立手順を説明するための図である。
【図８】図７に続く複合レンズ１の組立手順を説明するための図である。
【図９】図８に続く複合レンズ１の組立手順を説明するための図である。
【図１０】固定絞りの他の構成例を示す図である。
【図１１】固定絞りの組み立て方法を説明するための図である。
【図１２】組立状態の固定絞りの外観を示す斜視図である。
【図１３】本発明の第２の実施形態に係る複合レンズの構造を示す断面図である。
【図１４】固定絞り４０の構造を示す図である。
【図１５】固定絞り４０を成形するための金型の構成を示す断面図である。
【図１６】図１５に示す金型に樹脂を充填した状態を示す断面図である。
【図１７】図１６に示す状態から金型を開いた状態を示す断面図である。
【図１８】本発明の複合レンズの構造の変形例を示す断面図である。
【符号の説明】
１…複合レンズ、２…第１レンズ、２ｄ…テーパ面、２ｅ…当接面、１０…第２レンズ、１０ｄ…テーパ面、１０ｅ…当接面、２０…固定絞り、２１…固定絞り部材、２１ａ…開口孔、２１ｂ…テーパ面、２１ｃ…傾斜面。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a compound lens in which a fixed aperture is arranged and integrated between a plurality of lenses, a method for assembling the compound lens, a fixed aperture used for the compound lens, and a method for molding the fixed aperture.
[0002]
[Prior art]
In an optical system of a compound lens in which an aperture that allows a light beam to pass between two lenses and a fixed diaphragm that blocks unnecessary light beams are arranged, positioning accuracy between the lens and the fixed diaphragm is important.
If there is a deviation between the optical axis of the lens and the central axis of the aperture of the fixed aperture and a positional deviation in the optical axis direction, shading may occur in the image formed by the compound lens, resulting in a decrease in optical performance. To do.
Also, in order to effectively block unnecessary light bundles that do not contribute to image formation and suppress the occurrence of flare and ghost, it is common to place two fixed stops between two lenses. .
On the other hand, in order to construct an optical system of a compound lens in which a fixed aperture is arranged between the two lenses as described above, for example, a lens or a fixed aperture prepared separately as a lens barrel or a moving frame is used. Assemble.
[0003]
[Problems to be solved by the invention]
However, if an optical system of a compound lens is constructed by assembling a lens or a fixed aperture prepared as a separate part to a lens barrel or moving frame, it is difficult to ensure assembly accuracy, and in order to obtain desired optical performance In addition, there is a disadvantage that the alignment process between the lens and the fixed aperture increases, and the manufacturing cost increases.
In particular, in an optical system of a compound lens in which two fixed apertures are arranged between two lenses, it is necessary to align the center axes of the two fixed apertures and the optical axes of the two lenses. Is more difficult to secure.
[0004]
The present invention has been made in view of the above-described problems, and is a compound lens in which a fixed aperture is disposed between lenses, and a compound lens with improved positional accuracy between the lens and the fixed aperture, between the lenses, and between the fixed apertures. Another object of the present invention is to provide an assembling method capable of improving the positional accuracy and easily assembling the compound lens.
Another object of the present invention is to provide a fixed aperture that is preferable for use in the above-described compound lens and a method for forming the fixed aperture.
[0005]
[Means for Solving the Problems]
The compound lens of the present invention is provided between the first and second lenses and the first and second lenses, and is provided with an opening hole through which a light bundle passes, and the first and second lenses are provided. A fixed aperture that blocks an unnecessary beam among the transmitted light beams, and the first and second lenses and the fixed aperture are integrally assembled. And the second lens abut on each other in the optical axis direction and define a relative position in the optical axis direction, and a tapered portion that fits together and matches the optical axes of the first and second lenses Each of the fixed diaphragms is fitted to the inner periphery of the tapered portion of the first lens, defines a relative position in the optical axis direction with respect to the first lens, and is formed with a center axis of the aperture hole. A taper portion is provided to match the optical axis.
[0006]
The first lens, the second lens, and the fixed aperture are joined together by an adhesive.
[0007]
Preferably, the adhesive includes a back surface portion of the tapered portion of the fixed diaphragm, a part of the taper portion of the second lens, and a part of the end surface of the first lens facing the back surface portion. An adhesive accommodating space for accommodating the is formed.
[0008]
Preferably, the first and second lenses and the fixed diaphragm are made of resin.
[0009]
The tapered portions of the first and second lenses are tapered portions for facilitating release when the first and second lenses are molded by a molding die.
[0010]
The fixed throttle is composed of first and second fixed throttles that have the same shape and are arranged so as to overlap the opening holes.
[0011]
The opening holes of the first and second fixed diaphragms are inclined surfaces whose inner peripheral surfaces are enlarged in diameter from one opening end toward the other opening end, so that the end surfaces on the enlarged diameter side are in contact with each other. The taper portions are overlapped with each other and are arranged in directions away from each other.
[0012]
Preferably, the first and second fixed throttles are provided with fitting parts that are fitted together to define the relative positions of the first and second fixed throttle parts.
[0013]
More preferably, the fitting portion includes a protruding portion that protrudes from one end surface of the fixed throttle, and a through hole into which the protruding portion is fitted and inserted.
[0014]
The aperture of the fixed stop has a shape capable of blocking unnecessary light bundles at the opening end on the first lens side and the opening end on the second lens side.
[0015]
Preferably, the aperture hole of the fixed diaphragm is a concave surface whose inner peripheral surface is enlarged in diameter with respect to both opening ends.
[0016]
More preferably, the fixed diaphragm includes the tapered portions that are separated from each other on both sides in the optical axis direction.
[0017]
The method of assembling a compound lens according to the present invention includes a first lens and a second lens, and an aperture hole that is disposed between the first and second lenses and allows a light beam to pass therethrough. And a fixed stop for blocking unnecessary light bundles among the light bundles transmitted through the lens, and the first and second lenses and the fixed stop are integrally assembled. The outer periphery of the tapered portion formed along the central axis of the opening hole formed in the fixed aperture is fitted to the inner periphery of the tapered portion formed along the optical axis in the first lens. Determining the relative position in the optical axis direction with respect to the first lens, and aligning the center axis of the aperture with the optical axis, so that the second lens is disposed on the inner periphery of the tapered portion of the first lens. Further fit the outer periphery of the taper formed along the optical axis to the lens The optical axes of the first lens and the second lens are matched, and the first lens and the second lens are brought into contact with each other in the optical axis direction, so that the light of the first lens and the second lens Determine the relative axial position.
[0018]
In the compound lens assembling method of the present invention, first and second fixed apertures having the same shape are prepared, the opening holes of the fixed apertures are aligned with each other, and the tapered portions are separated from each other. And one tapered portion of each of the first and second fixed diaphragms is fitted to the tapered portion of the first lens, and the second lens has an inner periphery of the tapered portion of the first lens. The tapered portion is further fitted, and the first and second lenses are brought into contact with each other.
[0019]
The compound lens assembling method of the present invention comprises first and second fixed apertures having the same shape, which are integrally molded by the same molding die and partially connected to each other. The connecting portion of the diaphragm is bent so that the opening holes are aligned with each other and the tapered portions are separated from each other.
[0020]
The method for assembling a compound lens according to the present invention provides the first and second fixed apertures further comprising a fitting portion that fits each other and defines a relative position when the connecting portion is folded and overlapped, The first and second fixed apertures are overlapped by bending the connecting portions of the first and second fixed apertures and fitting the fitting portions.
[0021]
In the method of assembling the compound lens according to the present invention, after the tapered portion of the fixed aperture is fitted to the tapered portion of the first lens, a part of the tapered portion of the first lens and the taper of the fixed aperture member are provided. An adhesive is applied to a concave portion formed by a back surface portion of the portion, the second lens is fitted and brought into contact with the first lens, a part of the tapered portion of the first lens, and the The back part of the taper part of the fixed diaphragm and a part of the end face of the second lens facing the back part are joined by the adhesive.
[0022]
The compound lens assembling method of the present invention includes an opening hole having a shape capable of blocking unnecessary light bundles at the opening end on the first lens side and the opening end on the second lens side, and an optical axis. A fixed stop having the tapered portions that are separated from each other in both directions is prepared, and one of the tapered portions of the fixed stop is fitted into the tapered portion of the first lens.
[0023]
The fixed diaphragm of the present invention is disposed between the first and second lenses and includes an aperture hole through which the light beam passes, and an unnecessary light beam among the light beams that pass through the first and second lenses. The aperture of the fixed aperture is a concave surface whose inner peripheral surface is enlarged with respect to both aperture ends, and can block unnecessary beam bundles at each aperture end. Yes.
[0024]
Preferably, the fixed throttle is integrally formed of resin.
[0025]
The method for forming a fixed aperture according to the present invention is arranged between the first and second lenses and has an aperture hole through which the light beam passes, and is unnecessary among the light beams that pass through the first and second lenses. A method for forming a fixed aperture that resin-molds a fixed aperture that blocks a light beam, wherein the aperture hole of the fixed aperture is a concave surface whose inner peripheral surface is expanded in diameter relative to both ends of the aperture. Unnecessary beam bundle can be blocked at the opening end, and when forming the fixed aperture using a mold, for forming the opening hole for forming the opening hole installed in the cavity of the mold The pin is provided with an enlarged diameter portion that matches the concave surface, and the cavity is filled with resin, and after the resin is solidified, the resin is solidified from a fixed fixed resin and resists resistance due to the resin solidified. The pin is pulled out to form the opening hole.
[0026]
In the present invention, the tapered portion of the fixed diaphragm is fitted to the tapered portion of the first lens. As a result, the optical axis of the first lens coincides with the central axis of the aperture of the fixed aperture, and the relative position in the optical axis direction is determined. From this state, the tapered portion of the second lens is fitted into the tapered portion of the first lens, and the contact portions of the second lens are brought into contact with each other.
Thereby, the optical axes of the first lens and the second lens coincide with each other, and the relative position in the optical axis direction is determined.
As described above, according to the present invention, the first lens, the optical axis of the second lens, and the fixed aperture can be obtained by assembling the fixed aperture to the first lens and the second lens to the first lens. And the relative positioning of the first lens, the second lens, and the fixed diaphragm in the optical axis direction are performed simultaneously.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First embodiment
FIG. 1 is a cross-sectional view showing the structure of the composite lens according to the first embodiment of the present invention, and FIG. 2 is a cutaway perspective view of the composite lens shown in FIG.
A compound lens 1 shown in FIG. 1 includes a first lens 2, a second lens 10, and a fixed diaphragm 20.
[0028]
The first lens 2 is obtained, for example, by injection molding a resin material such as transparent plastic using a mold.
The first lens 2 includes a spherical lens surface 2 a on one end surface side in the optical axis direction, and a planar lens surface 2 c on the other end surface side facing the second lens 10. The first lens 2 is used for integrally assembling the first lens 2 with the second lens 10 and the fixed aperture 20 on the outer periphery of the lens surfaces 2a and 2c, and for incorporating the first lens 2 into the lens barrel. A non-lens portion 2b is provided.
[0029]
At the boundary between the non-lens portion 2b of the first lens 2 and the lens surface 2a, a groove 2t is formed along the circumferential direction. The groove 2t has a taper so that the first lens 2 can be easily released from the mold.
[0030]
On the lens surface 2c side of the non-lens portion 2b, a tapered surface 2d that is inclined with respect to the optical axis at a predetermined angle, for example, 45 degrees is formed. A contact surface 2e perpendicular to the optical axis is formed on the outer periphery of the tapered surface 2d. The tapered surface 2d and the abutting surface 2e are molded by a mold surface processed with high precision in the same manner as the mold surfaces of the lens surfaces 2a and 2c in the mold for molding the first lens 2.
As will be described later, the fixed aperture 20 and the second lens 10 are fitted to the tapered surface 2d. Further, the tapered surface 2d is inclined to facilitate the release of the first lens 2 from the mold.
[0031]
The second lens 10 is obtained, for example, by injection molding a resin material such as transparent plastic using a mold.
The second lens 10 is a meniscus lens provided with a spherical lens surface 10 a on one end surface side in the optical axis direction and a spherical lens surface 10 c on the other end surface side facing the first lens 2.
The second lens 10 is used for assembling the second lens 10 integrally with the first lens 2 and the fixed aperture 20 on the outer periphery of the lens surfaces 10a and 10c, and for incorporating the second lens 10 into the lens barrel. A non-lens portion 10b is provided.
[0032]
At the boundary between the non-lens portion 10b of the second lens 10 and the lens surface 10a, a groove portion 10t is formed along the circumferential direction. The groove 10t has a taper so that the second lens 10 can be easily released from the mold.
[0033]
An end surface 10f that faces the fixed diaphragm 20 is formed on the outer periphery of the lens surface 10c of the second lens 10, and a tapered surface 10d that fits with the tapered surface 2d of the first lens 2 is formed on the outer periphery of the end surface 10f. ing. The tapered surface 10d is inclined with respect to the optical axis at the same angle as the tapered surface 2d of the first lens 2.
By fitting the tapered surface 2d of the first lens 2 and the tapered surface 10d of the second lens 10 together, the optical axes of the first lens 2 and the second lens 10 are matched.
[0034]
A contact surface 10 e that is orthogonal to the optical axis and contacts the contact surface 2 e of the first lens 2 is formed on the outer periphery of the tapered surface 10 d of the second lens 10. When the contact surface 2e of the first lens 2 and the contact surface 10e of the second lens 10 contact each other, the relative positions of the first lens 2 and the second lens 10 in the optical axis direction are determined.
In the state where the contact surface 2e of the first lens 2 and the contact surface 10e of the second lens 10 are in contact with each other, the taper surface 2d of the first lens 2 and the taper surface 10d of the second lens 10 are between. Is formed so as to have a clearance within a range that satisfies the optical performance required for the compound lens 1.
Further, the taper surface 10d and the contact surface 10e are molded by a mold surface processed with high accuracy in the same manner as the mold surfaces of the lens surfaces 10a and 10c in the mold for molding the second lens 10.
[0035]
The fixed diaphragm 20 is configured by overlapping two fixed diaphragm members 21 having the same shape.
These two fixed throttle members 21 are formed from, for example, a black resin obtained by adding glass to polycarbonate.
3A and 3B are diagrams showing the structure of the fixed throttle member 21, wherein FIG. 3A is a plan view, and FIG. 3B is a cross-sectional view taken along the line AA in FIG.
As shown in FIG. 3, the fixed throttle member 21 is made of a disk-shaped member and includes an opening hole 21a at the center. As shown in FIG. 3B, the opening hole 21a is an inclined surface 21c in which the diameter of the inner peripheral surface increases from the opening end on the one end surface 21d side toward the opening end of the other end surface 21f.
[0036]
On the outer periphery of the fixed aperture member 21, a tapered surface 21b that is fitted to the inner periphery of the tapered surface 2d of the first lens 2 and is inclined with respect to the central axis of the opening hole 21a at the same angle as the tapered surface 2d is formed. Yes. By fitting the tapered surface 21b of the fixed aperture member 21 to the tapered surface 2d of the first lens 2, the central axis of the opening hole 21a matches the optical axis of the first lens 2. Further, the relative position of the fixed aperture member 21 and the first lens 2 in the optical axis direction is determined.
[0037]
As shown in FIG. 1, the two fixed throttle members 21 configured as described above are overlapped so that the positions of the opening holes 21a coincide. Moreover, it overlaps so that the end surfaces 21f by which the diameter of the opening hole 21a was expanded may contact. In this state, the tapered surfaces 21b of the fixed throttle members 21 are arranged in directions away from each other.
Since the two fixed aperture members 21 have the inclined surfaces 21c formed in the opening holes 21a, the light bundle can be blocked at the opening end on the small diameter side of each opening hole 21a.
The opening hole of the fixed aperture 20 in which the two fixed aperture members 21 are overlapped has a concave inner peripheral surface, and unnecessary light reflected by the inner peripheral surface can be blocked.
[0038]
As shown in FIG. 1, of the two fixed aperture members 21, the tapered surface 21 b of one fixed aperture member 21 is fitted to the tapered surface 2 d of the first lens 2.
On the other hand, the tapered surface 21 b of the other fixed aperture member 21 is located on the back side of the tapered surface 21 b that fits with the tapered surface 2 d of the first lens 2.
A space for accommodating the adhesive G is formed between the tapered surface 21 b of the other fixed aperture member 21 and a part of the end surface 10 f of the second lens 10 and the tapered surface 2 d of the first lens 2. . The first lens 2, the second lens 10, and the fixed diaphragm 20 are joined to each other by the adhesive G filled in this space.
[0039]
A predetermined clearance is formed between the end surface 10 f of the second lens 10 and the end surface of the other fixed diaphragm member 21. This clearance is provided so as not to hinder the positioning of the first lens 2 and the second lens 10 in the optical axis direction due to the contact between the contact portion 2e of the first lens 2 and the contact portion 10e of the second lens 10. ing.
Further, this clearance is defined in a range in which the amount of displacement of the fixed aperture member 21 does not affect the optical performance of the compound lens 1.
[0040]
Next, an example of a method for assembling the compound lens 1 having the above configuration will be described with reference to FIGS.
First, as shown in FIG. 4, the first lens 2 and the fixed aperture member 21 are prepared, and the tapered surface 21 b of the fixed aperture member 21 is fitted toward the tapered surface 2 d of the first lens 2.
By fitting the tapered surface 21 b of the fixed aperture member 21 to the tapered surface 2 d of the first lens 2, as shown in FIG. 5, the outer peripheral end surface 2 f of the lens surface 2 c of the first lens 2 and the fixed aperture member 21. A predetermined amount of gap is accurately formed between the end face 21d. This gap affects the optical performance of the compound lens 1.
Further, by fitting the tapered surface 21 b of the fixed aperture member 21 to the tapered surface 2 d of the first lens 2, the central axis of the opening hole 21 a of the fixed aperture member 21 and the optical axis of the first lens 2 coincide.
[0041]
Next, as shown in FIG. 6, a fixed aperture member 21 is further prepared for the fixed aperture member 21 fitted in the first lens 2.
A newly prepared fixed diaphragm member 21 is superposed on the fixed diaphragm member 21 in a state of being fitted to the first lens 2 to obtain the state shown in FIG.
At this time, they are overlapped so that the end faces 21f of the fixed throttle member 21 face each other. That is, two fixed throttle members 21 having the same shape are overlapped with each other upside down.
Further, alignment work between the two fixed throttle members 21 is also required so that the central axes of the opening holes 21a of the two fixed throttle members 21 coincide with each other.
[0042]
Next, as shown in FIG. 8, the tapered surface 21 b of the fixed aperture member 21 that is not fitted to the tapered surface 2 d of the first lens 2 and the first lens 2 out of the two fixed aperture members 21 overlapped with each other. An appropriate amount of adhesive G is applied to the recess formed between the tapered surface 2d using, for example, a dispenser D.
The adhesive G may be applied to the entire circumference of the recess formed between the tapered surface 21b of the fixed diaphragm member 21 and the tapered surface 2d of the first lens 2, but it is the minimum essential for joining. It is preferable to apply to a limited part. This is to prevent the adhesive G from affecting the optical performance of the compound lens 1.
[0043]
Next, as shown in FIG. 9, the second lens 10 is assembled to the first lens 2 in a state where the adhesive G is applied.
When the second lens 10 is assembled to the first lens 2, the tapered surface 10 d of the second lens 10 is fitted to the tapered surface 2 d of the first lens 2, and the first contact surface 2 e of the first lens 2 is The contact surface 10e of the two lens 10 contacts. Thereby, the optical axes of the first lens 2 and the second lens 10 are matched, and the relative position in the optical axis direction is determined.
[0044]
Further, a part of the end surface 10 f of the second lens 10 comes into contact with the adhesive G applied to the concave portion formed between the tapered surface 21 b of the fixed aperture member 21 and the tapered surface 2 d of the first lens 2. When the adhesive G is solidified, a part of the end surface 10f of the second lens 10, a part of the tapered surface 21b of the fixed aperture member 21, and a part of the tapered surface 2d of the first lens 2 are joined.
Thereby, the assembly of the compound lens 1 is completed.
[0045]
As described above, in the compound lens 1 of the present embodiment, the first lens 2 and the second lens 10 and the fixed diaphragm 20 including the two fixed diaphragm members 21 are integrated to form a single component. For example, when the lens 1 is assembled to a lens barrel, it is not necessary to position the first lens 2, the second lens 10, and the fixed aperture 20.
Further, in the compound lens 1 of the present embodiment, the fixed aperture 20 is fitted to the tapered surface 2d for improving the releasability of the first lens 2 from the mold, and the second surface is also fitted to the tapered surface 2d. Since the tapered surface 10d of the lens 10 is fitted, the tapered surface 2d and the tapered surface 10d can be easily formed by a mold.
[0046]
Further, according to the method for assembling the compound lens 1 of the present embodiment, high-precision positioning can be achieved by simply fitting the fixed aperture member 21 to the first lens 2 and fitting the second lens 10 to the first lens 2. This eliminates the need for alignment and alignment work and simplifies the assembly process.
Further, according to the method of assembling the compound lens 1 of the present embodiment, after the two fixed aperture members 21 are assembled into the first lens 2, the first lens 2, the two lenses are simply applied by applying the adhesive G. The fixed aperture member 21 and the second lens 10 can be joined simultaneously, and the assembly process can be further simplified.
[0047]
In the above-described embodiment, when the two fixed throttle members 21 are overlapped, it is necessary to accurately align the central axis between the fixed throttle members 21.
A fixed diaphragm having a structure capable of simplifying the alignment operation between the fixed diaphragm members will be described.
10A and 10B are diagrams showing another example of the fixed diaphragm, in which FIG. 10A is a plan view and FIG. 10B is a cross-sectional view in the BB line direction of FIG. In FIG. 10, the same components as those of the fixed diaphragm 20 are denoted by the same reference numerals.
[0048]
The fixed throttle 30 shown in FIG. 10 includes two fixed throttle members 21, and the outer periphery of these fixed throttle members 21 is partially connected by a connecting portion 22.
Each of the fixed throttle members 21 has a disk shape as a basic shape, and is a flat portion 21d in which a part of the outer periphery where the connecting portion 22 is formed is flattened. The connecting portion 22 is thinner than the thickness of each fixed throttle member 21.
An opening hole 21a is formed at the center of each fixed throttle member 21, and the inner peripheral surface of the opening hole 21a is an inclined surface 21c.
A tapered surface 21 b that fits with the tapered surface 2 d of the first lens 2 is formed on the outer periphery of each fixed aperture member 21.
[0049]
Of the two fixed throttle members 21, a fitting projection 21h is formed on the end face 21f of one fixed throttle member 21, and the other fixed throttle member 21 has a fitting hole into which the fitting projection 21h is fitted. 21i is formed.
The end surface 21f on which the fitting protrusion 21h is formed is an end surface on which the opening end on the diameter expansion side of the opening hole 21a is located.
[0050]
The fixed aperture 30 composed of the two fixed aperture members 21 connected as described above is integrally formed by a mold.
As the molding material, for example, a resin material such as polyacetal is used. If polyacetal is used as the material of the fixed aperture 30, it is a relatively flexible material, so that the connecting portion 22 is not broken when the connecting portion 22 is bent.
[0051]
As shown in FIG. 11, the fixed diaphragm 30 having the above configuration is overlapped with the connecting portion 22 before being assembled into the first lens 2.
At this time, the end face 21f of the fixed throttle member 21 is bent in the facing direction, and the fitting hole 21i is fitted into the fitting protrusion 21h.
[0052]
When the fixed throttle members 21 are overlapped, the central axes of the opening holes 21a of the fixed throttle members 21 coincide with each other as shown in FIG. Further, the tapered surfaces 21b of the fixed throttle member 21 are overlapped in directions away from each other.
Further, since the flat portion 21 g is formed on the fixed throttle member 21, the bent connecting portion 22 is within the outer diameter of the fixed throttle member 21.
[0053]
In this way, one of the two fixed aperture members 21 of the fixed aperture 30 on which the fixed aperture members 21 are overlapped, one of the tapered surfaces 21 b is fitted to the tapered surface 2 d of the first lens 2.
Further, the fixed aperture 30 is assembled to the tapered surface 2 d of the first lens 2 in the state where the connecting portion 22 exists.
[0054]
As described above, the two fixed throttle members 21 having the same basic shape are integrally formed with the fixed throttle 30 connected by the connecting portion 22, and the two fixed throttle members 21 are folded to fix the two fixed throttle members 21. The alignment work between the diaphragm members 21 is not necessary.
In addition, since the fitting protrusion 21h is formed on the one end face 21f of the fixed throttle member 21, the direction when the two fixed throttle members 21 are overlapped is not mistaken.
Further, since the fixed diaphragm 30 has the same shape on the front side and the back side in the folded state, it is not necessary to be aware of the front and back when the fixed diaphragm 30 is assembled to the first lens 2.
[0055]
Second embodiment
FIG. 13 is a cross-sectional view showing the structure of a compound lens according to the second embodiment of the present invention. In addition, the same code | symbol is attached | subjected about the component same as the compound lens 1 which concerns on 1st Embodiment mentioned above.
A compound lens 100 shown in FIG. 13 includes a first lens 2, a second lens 10, and a fixed aperture 40. The first lens 2 and the second lens 10 have the same configuration as the compound lens 1 according to the first embodiment described above.
A fixed diaphragm 40 is disposed between the first lens 2 and the second lens 10. The fixed aperture 40 has the same arrangement as the fixed aperture 20 or 30 according to the first embodiment described above.
[0056]
14A and 14B are diagrams showing the structure of the fixed aperture 40, in which FIG. 14A is a plan view, and FIG. 14B is a cross-sectional view taken along the line C-C in FIG.
As shown in FIG. 14, the fixed stop 40 is formed of a disk-shaped member and includes an opening hole 40a through which the light beam passes at the center.
On the outer periphery of the fixed diaphragm 40, tapered surfaces 40b and 40c are formed on both sides in the optical axis direction so as to be separated from each other. The tapered surfaces 40b and 40c are inclined with respect to the central axis of the opening hole 40a at the same angle as the tapered surface 2d of the first lens 2.
By fitting the tapered surface 40b or 40c of the fixed aperture 40 to the tapered surface 2d of the first lens 2, the central axis of the opening hole 40a matches the optical axis of the first lens 2. Furthermore, the relative position of the fixed aperture 40 and the first lens 2 in the optical axis direction is determined.
[0057]
The aperture 40a of the fixed aperture 40 has a shape capable of blocking unnecessary light bundles at both aperture ends 40e and 40f. In other words, the opening hole 40a performs the same function as when two stops are arranged.
Specifically, the opening hole 40a of the fixed aperture 40 has a concave surface 40d whose inner peripheral surface is enlarged in diameter with respect to both opening ends 40e and 40f.
By forming the aperture hole 40a of the fixed aperture 40 in such a shape, light that passes through one aperture end 40e and is reflected by the concave surface 40d is blocked by the other aperture end 40f, and does not contribute to image formation. The light bundle can be effectively blocked, and the occurrence of flare and ghost can be suppressed.
[0058]
Next, a method for forming the fixed aperture 40 will be described.
FIG. 15 is a diagram showing a configuration of a mold for integrally forming the fixed aperture 40.
The mold for integrally molding the fixed aperture 40 includes a fixed mold 300 having a mold surface 300a for molding one side of the fixed aperture 40, and a movable mold having a mold surface 200a for molding the other side of the fixed aperture 40. A mold 200 is used.
Further, in the cavity C formed between the movable mold 200 and the fixed mold 300, an opening hole forming pin having a diameter-enlarged portion 400 a that matches the shape of the opening hole 40 a of the fixed aperture 40 at the tip portion. 400 is installed. The opening hole forming pin 400 is inserted into the insertion hole 300b formed in the fixed mold 300, and only the enlarged diameter portion 400a is placed in the cavity C.
The fixed mold 300 is provided with an extrusion pin 500 for separating the molded product from the fixed mold 300 so as to protrude from the mold surface 300a.
[0059]
As shown in FIG. 15, in a state where the movable mold 200 and the fixed mold 300 are clamped, resin is filled from a gate (not shown) communicating with the cavity C.
As a resin material to be used, for example, a resin material such as polyacetal is used.
[0060]
As shown in FIG. 16, when the resin is filled in the cavity C and the resin is solidified, the fixed aperture 40 is formed.
When the fixed throttle 40 is formed, as shown in FIG. 17, the fixed throttle 40 is pushed out by the push pin 500 while the movable mold 200 is opened with respect to the fixed mold 300, thereby being separated from the fixed mold 300.
[0061]
At this time, since the inner periphery of the opening hole 40a of the fixed aperture 40 is a concave surface 40d, it is difficult for the fixed aperture 40 to come off from the enlarged diameter portion 400a of the aperture hole forming pin 400, but it is forcibly pulled out.
By using a relatively flexible resin such as polyacetal as the resin for forming the fixed aperture 40, the fixed aperture 40 is damaged even if the fixed aperture 40 is forcibly pulled out from the enlarged diameter portion 400a of the opening hole forming pin 400. Can be prevented.
[0062]
In the fixed aperture 40 formed by the above-described forming method, one of the tapered surfaces 40b and 40c is fitted to the tapered surface 2d of the first lens 2 and the other of the tapered surfaces 40b and 40c is similar to the above-described assembly method. An adhesive is applied to a recess formed by a part of the tapered surface 2 d of the first lens 2.
From this state, the second lens 10 is assembled to the first lens 2, and the first lens 2, the fixed aperture 40 and the second lens 10 are joined by an adhesive, and the composite lens 100 is completed.
[0063]
As described above, according to the present embodiment, it is not necessary to form the two fixed throttle members by forcibly forming the opening hole 40a of the fixed throttle 40 having two throttle functions. Further, the process of superimposing the two fixed throttle members is not necessary.
[0064]
Although the present invention has been described with reference to various embodiments, the present invention is not limited to the above-described embodiments.
In the first and second embodiments described above, the case where there are two opening ends for the diaphragm has been described, but the present invention can also be applied to the case of one fixed diaphragm.
[0065]
In the above-described embodiment, a space for accommodating the adhesive G is formed between the tapered surface 21b of the fixed diaphragm member 21 and a part of the end surface 10f of the second lens 10 and the tapered surface 2d of the first lens 2. The first lens 2, the second lens 10, and the fixed aperture 20 are joined to each other by filling the space with the adhesive G, but the present invention is not limited to this.
For example, as shown in FIG. 18, the outer periphery of the contact surface 2 e of the first lens 2 is an extraction taper portion that facilitates release from the mold, and the extraction taper portion and the second lens 10 A recess is formed between the contact surface 10e. For this reason, it is also possible to join the first lens 2 and the second lens 10 by filling the concave portion with the adhesive G.
[0066]
【The invention's effect】
According to the present invention, in a compound lens in which a fixed aperture is arranged between lenses, the positional accuracy between the lens and the fixed aperture, between the lenses, and between the fixed aperture can be improved. The alignment process between the lenses and between the two fixed aperture members can be eliminated.
Further, by handling the compound lens according to the present invention as one component, it is easy to handle and the assembly to the lens barrel or the like is also simplified.
In addition, flare and ghost can be effectively suppressed by incorporating two fixed apertures.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a structure of a compound lens according to a first embodiment of the present invention.
FIG. 2 is a cutaway perspective view of the compound lens shown in FIG.
FIG. 3 is a diagram showing a structure of a fixed diaphragm 21. FIG.
FIG. 4 is a view for explaining an assembly procedure of the compound lens 1;
5 is a view for explaining an assembly procedure of the compound lens 1 following FIG. 4; FIG.
6 is a view for explaining an assembly procedure of the compound lens 1 subsequent to FIG. 5. FIG.
7 is a view for explaining an assembly procedure of the compound lens 1 subsequent to FIG. 6. FIG.
8 is a view for explaining an assembly procedure of the compound lens 1 subsequent to FIG. 7; FIG.
FIG. 9 is a diagram for explaining an assembling procedure of the compound lens 1 following FIG. 8;
FIG. 10 is a diagram illustrating another configuration example of the fixed aperture.
FIG. 11 is a diagram for explaining a method of assembling a fixed aperture.
FIG. 12 is a perspective view showing an appearance of a fixed diaphragm in an assembled state.
FIG. 13 is a cross-sectional view showing the structure of a compound lens according to a second embodiment of the present invention.
14 is a view showing a structure of a fixed aperture 40. FIG.
FIG. 15 is a cross-sectional view showing a configuration of a mold for forming the fixed aperture 40. FIG.
16 is a cross-sectional view showing a state in which the mold shown in FIG. 15 is filled with resin.
17 is a cross-sectional view showing a state where a mold is opened from the state shown in FIG.
FIG. 18 is a sectional view showing a modification of the structure of the compound lens of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Composite lens, 2 ... 1st lens, 2d ... Tapered surface, 2e ... Contact surface, 10 ... 2nd lens, 10d ... Tapered surface, 10e ... Contact surface, 20 ... Fixed stop, 21 ... Fixed stop member, 21a ... Opening hole, 21b ... Tapered surface, 21c ... Inclined surface.

Claims

A first lens and a second lens;
A fixed stop disposed between the first and second lenses, having an aperture hole through which the light bundle passes, and blocking an unnecessary light bundle among the light bundles transmitted through the first and second lenses; Wherein the first and second lenses and the fixed diaphragm are integrally assembled,
The first and second lenses are in contact with each other in the optical axis direction, and are fitted to each other so as to match the optical axes of the first and second lenses with a contact portion that defines a relative position in the optical axis direction. Each with a tapered portion,
The fixed diaphragm is fitted to the inner periphery of the tapered portion of the first lens, defines a relative position in the optical axis direction with respect to the first lens, and has a central axis and an optical axis of the aperture hole. A compound lens having a tapered portion to be matched.

The composite lens according to claim 1, wherein the first lens, the second lens, and the fixed aperture are joined to each other by an adhesive.

Adhesive housing the adhesive by a back surface portion of the tapered portion of the fixed diaphragm, a portion of the taper portion of the second lens, and a portion of the end surface of the first lens facing the back surface portion. The compound lens according to claim 2, wherein an agent storage space is formed.

The compound lens according to claim 1, wherein the first and second lenses and the fixed aperture are made of resin.

5. The compound lens according to claim 4, wherein the tapered portions of the first and second lenses are tapered portions for facilitating mold release when the first and second lenses are molded by a molding die. .

2. The compound lens according to claim 1, wherein the fixed diaphragm has the same shape and is configured by first and second fixed diaphragm members arranged to overlap with each other so that the opening holes coincide with each other.

The opening holes of the first and second fixed throttle members are inclined surfaces whose inner peripheral surfaces are expanded in diameter from one opening end toward the other opening end,
The composite lens according to claim 6, wherein the end surfaces on the side of the enlarged diameter are overlapped so as to be in contact with each other, and the respective tapered portions are arranged in directions away from each other.

The compound lens according to claim 7, wherein the first and second fixed apertures include a fitting portion that is fitted to each other and defines a relative position of the first and second fixed aperture portions.

The composite lens according to claim 8, wherein the fitting portion includes a protruding portion that protrudes from one end surface of the fixed aperture, and a through hole into which the protruding portion is fitted and inserted.

2. The compound lens according to claim 1, wherein the aperture of the fixed diaphragm has a shape capable of blocking unnecessary light bundles at an opening end on the first lens side and an opening end on the second lens side, respectively. .

The composite lens according to claim 10, wherein the aperture hole of the fixed diaphragm is a concave surface whose inner peripheral surface is enlarged in diameter with respect to both opening ends.

The composite lens according to claim 10, wherein the fixed diaphragm includes the tapered portions that are separated from each other on both sides in the optical axis direction.

A predetermined clearance is formed between an end surface on the second lens side in the optical axis direction of the fixed diaphragm and an end surface facing the end surface of the second lens,
2. The compound lens according to claim 1, wherein the clearance defines a positional deviation amount of the fixed stop in an optical axis direction within a range in which a desired optical performance can be obtained.

Out of the light bundles that are arranged between the first and second lenses and the first and second lenses and that have an aperture hole that allows the light bundles to pass therethrough, and that pass through the first and second lenses. A fixed aperture that blocks a light bundle, and a method of assembling a composite lens in which the first and second lenses and the fixed aperture are integrally assembled,
The outer periphery of the tapered portion formed along the central axis of the opening hole formed in the fixed aperture is fitted to the inner periphery of the tapered portion formed along the optical axis in the first lens, Determining the relative position of the first lens in the optical axis direction, and matching the central axis of the aperture with the optical axis;
The outer periphery of the taper portion formed along the optical axis of the second lens is further fitted to the inner periphery of the taper portion of the first lens, and the optical axes of the first lens and the second lens are further fitted. And the first lens and the second lens are brought into contact with each other in the optical axis direction to determine the relative position of the first lens and the second lens in the optical axis direction.

First and second fixed throttles having the same shape are prepared,
The opening holes of the fixed diaphragms are aligned with each other, and the taper portions are overlapped in a direction away from each other,
Fitting one tapered portion of the first and second fixed apertures with the tapered portion of the first lens;
The compound lens assembly according to claim 14, wherein the tapered portion of the second lens is further fitted to the inner periphery of the tapered portion of the first lens, and the first and second lenses are brought into contact with each other. Method.

Prepare first and second fixed throttles of the same shape, which are integrally molded with the same molding die and partially connected to each other,
The compound lens assembling method according to claim 15, wherein the connecting portions of the first and second fixed diaphragms are bent so that the opening holes are aligned with each other and the tapered portions are separated from each other.

Preparing the first and second fixed apertures further comprising a fitting portion that fits each other and defines a relative position when the connecting portion is folded and overlapped;
17. The method of assembling a compound lens according to claim 16, wherein the first and second fixed apertures are overlapped by bending the connecting portions of the first and second fixed apertures and fitting the fitting portions.

A concave portion formed by a part of the tapered portion of the first lens and a back surface portion of the tapered portion of the fixed aperture member after the tapered portion of the fixed aperture is fitted to the tapered portion of the first lens. Apply adhesive to the
Fitting and contacting the second lens to the first lens;
The part of the taper part of the first lens, the back part of the taper part of the fixed diaphragm, and the part of the end surface of the second lens facing the back part are joined by the adhesive. 14. A method for assembling the compound lens according to 14.

The tapered portion having an opening hole having a shape capable of blocking an unnecessary light bundle at each of the opening end on the first lens side and the opening end on the second lens side, and separated from each other on both sides in the optical axis direction Prepare a fixed aperture with
The compound lens assembling method according to claim 14, wherein one of the tapered portions of the fixed diaphragm is fitted into the tapered portion of the first lens.

A fixed aperture that is disposed between the first and second lenses, has an aperture hole through which the light beam passes, and blocks an unnecessary light beam among the light beams that pass through the first and second lenses. And
The aperture of the fixed aperture is a fixed aperture in which the inner peripheral surface is a concave surface whose diameter is expanded with respect to both aperture ends, and an unnecessary light bundle can be blocked at each aperture end.

The fixed aperture according to claim 20, wherein the fixed aperture is integrally formed of resin.

A fixed aperture disposed between the first and second lenses and having an aperture hole through which the light beam passes at the center, and blocking an unnecessary light beam among the light beams transmitted through the first and second lenses, is made of resin. A method of forming a fixed aperture for molding,
The aperture hole of the fixed diaphragm is a concave surface whose inner peripheral surface is enlarged in diameter with respect to both opening ends, and can block unnecessary light bundles at each opening end,
When forming the fixed aperture using a mold, an opening hole forming pin for forming the opening hole installed in the cavity of the mold is provided with a diameter-enlarged portion that matches the concave surface,
After the resin is solidified in the cavity and the resin is solidified, the fixed aperture for forming the aperture hole by pulling out the aperture hole forming pin against the resistance caused by the solidified resin from the molded fixed aperture Molding method.