JP2004345880A

JP2004345880A - Production method for lens having ball casing

Info

Publication number: JP2004345880A
Application number: JP2003142250A
Authority: JP
Inventors: Shinichi Nishikawa; 愼一西川; Yoshio Ushino; 美穂牛野; Yoshihiro Kamata; 義浩釜田
Original assignee: Minolta Co Ltd
Current assignee: Minolta Co Ltd
Priority date: 2003-05-20
Filing date: 2003-05-20
Publication date: 2004-12-09

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method whereby a lens having a ball casing united therewith is produced at a low cost with high productivity by molding a lens material and whereby a small-sized lens can be produced. <P>SOLUTION: The production method is as follows: a drag 1 and a cope 2 are prepared; a ball casing F is arranged so as to face a drag molding face 11; a specified amount of molten glass g drops are dropped onto the drag molding face; while glass g is at a temperature at which it is press-deformable, the glass g is press molded with the drag 1 and the cope 2; and the resultant lens 10 having a ball casing is taken out. The ball casing F is heated before or/(and) after the ball-casing arranging step so that the temperature of the ball casing F after the press molding step is higher than a temperature (°C) lower by 100°C than the glass transition temperature of the glass g drops. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は玉枠付レンズの製造方法、特にレンズ材料の成形により玉枠と一体化されたレンズを形成する玉枠付レンズの製造方法に関する。
【０００２】
【従来の技術】
リング状、筒状等の玉枠内にレンズを保持させた所謂玉枠付レンズは様々の光学機器分野や光学機器を含む各種技術分野で採用されている。例えば、光通信分野では、光ファイバーからの光を光センサーへ導入したり、レーザ光を光ファイバーへ導くこと等に利用されている。
玉枠付レンズにはレンズと玉枠との結合態様等により種々のタイプのものがあるが、その一つに、レンズがレンズ材料の成形により玉枠と一体化される状態に形成された玉枠付レンズがある。
【０００３】
このような玉枠付レンズの製造方法については、例えば、特公昭６３−５３５２２号公報に、側面に複数の貫通孔を形成した鏡胴内にレンズ材料を配置し、該レンズ材料の一部が該貫通孔に流入して固化するように該レンズ材料を加圧成形することで該鏡胴に保持されたレンズを形成することが開示されている。また、特開平３−２３７０２３号公報には、レンズホルダの穴内に成形用ガラス素材を配置し、これを成形することで該ホルダに保持されたレンズを形成することが開示されている。
【０００４】
これら公報に開示された方法における鏡胴やレンズホルダ内に配置されるレンズ素材は、予め所定重量及び形状に作製されたものであり、該レンズ素材は成形用金型とともに加熱され、成形後は取り出しのために金型とともに室温付近まで冷却される。
【０００５】
一方、レンズの製造方法として、所定重量及び形状に作製されたレンズ素材を金型とともに加熱して加圧成形し、その後金型とともに冷却してレンズを取り出す方法とは全く異なる次の方法が提案されている。
【０００６】
すなわち、特開平４−１６４１４号公報は、ノズル先端から所定量の溶融ガラス滴を成形型上に滴下し、滴下されたガラス滴が未だ変形可能な温度にある間に該成形型でレンズを加圧成形する方法を開示している。
【０００７】
また、特開平４−１６４１４号公報に開示された成形方法では、ノズルからの自然落下による溶融ガラス滴の大きとしては１００ｍｇ以下の微小なものを得ることは困難であったところ、特開２００２−１５４８３４号公報は、ノズルからの溶融ガラスの滴下路の途中に貫通細孔を形成した滴下量調整部材を配置し、該滴下量調整部材上にガラス滴を滴下衝突させることで該ガラス滴の少なくとも一部を微小滴として該部材細孔から押し出すことで微小なガラス滴を得ることを開示している。
【０００８】
【特許文献１】特公昭６３−５３５２２号公報
【特許文献２】特開平３−２３７０２３号公報
【特許文献３】特開平４−１６４１４号公報
【特許文献４】特開２００２−１５４８３４号公報
【０００９】
【発明が解決しようとする課題】
しかしながら、特公昭６３−５３５２２号公報に開示された鏡胴付レンズの製法や特開平３−２３７０２３号公報に開示されたホルダ付レンズの製法においては、レンズ自体の形成についてみれば、所定重量及び形状の成形用レンズ素材を精度よく作製する工程が欠かせず、特にレンズ素材重量を厳密に管理する必要があること、及び該レンズ素材と金型とを加熱、冷却する工程に長時間を必要とすることから、レンズを低コスト化することが困難である。
【００１０】
この点、特開平４−１６４１４号公報や特開２００２−１５４８３４号公報に開示されたレンズ製法によると、ノズル先端からの自然滴下による溶融ガラス滴を用いるため、作製が高価につくレンズ素材を必要とせず、さらに、レンズ素材と金型を室温から加熱し、成形後に再び冷却するという工程が不要になり、レンズ製造時間の大幅な短縮が可能である。これらにより、成形用レンズ素材を金型とともに加熱、冷却して成形する方法よりも大幅にレンズ製造コストを低減でき、レンズの生産性を高めることができる。
【００１１】
しかし、特開平４−１６４１４号公報や特開２００２−１５４８３４号公報は、それらに開示されたレンズ製造方法の玉枠付レンズの製法への応用については何ら開示していない。
【００１２】
そこで本発明は、レンズ材料の成形により玉枠と一体化されたレンズを形成する玉枠付レンズの製造方法であって、かかる玉枠付レンズを低コストで、生産性高く製造でき、レンズの小型化にも対応できる玉枠付レンズの製造方法を提供することを課題とする。
【００１３】
【課題を解決するための手段】
本発明者は前記課題を解決すべく研究を重ね、次のことに着目し本発明を完成した。
先ず、レンズそれ自体については、特開平４−１６４１４号公報等に開示された溶融ガラス滴の成形によるレンズ製造方法と基本的に同様の方法を採用することで、成形用レンズ素材を作製することは不要となり、かかるレンズ素材を成形用型とともに加熱、冷却する必要もないから、低コストで、生産性高くレンズを製造することができる。
【００１４】
レンズを玉枠に保持させる点については、ガラス滴を加圧成形するにあたり、予め玉枠を下型に対し、該玉枠の内部空間に該下型の成形面が臨む所定位置関係で配置しておき、その状態で下型上に溶融ガラス滴を滴下すれば、ガラス滴は下型に衝突して広がり、玉枠に接触するので、これを加圧成形すれば、成形されるレンズ外周部が玉枠に保持される恰好となり、これにより玉枠付レンズを得ることができる。
【００１５】
また、このような手法によると、加圧成形の段階ではなく、溶融ガラス滴の滴下の段階でガラスと玉枠とが一体化されるので、その後の加圧成形の条件に影響されにくい状態で、ガラスと玉枠との安定した結合が得られる。
【００１６】
また、滴下された溶融ガラス滴は、主に下型及び玉枠との接触面からの放熱によって冷却されるが、玉枠の温度をガラス滴のガラス転移点温度（℃）から１００℃を差し引いた温度より高くしておけば、玉枠に接触して放熱するガラス滴部分の温度低下を抑制でき、加圧成形時の該部分の割れや欠け等の損傷を抑制することができ、良好なレンズを得ることができる。
【００１７】
また、玉枠を用いてレンズを成形すると、ガラス滴のレンズ外周部に相当する部分が玉枠により位置規制されるから、規制なく自由状態で形成されるコバ部が生じることがない。従って、玉枠のサイズ及び滴下ガラス量を選択することでレンズの小型化も可能である。
【００１８】
以上の点に着目し、本発明は、
製造しようとする玉枠付レンズを構成するためのレンズの一つの光学機能面を成形するための下型成形面を有する下型と、該レンズのもう一つの光学機能面を成形するための上型成形面を有し、該下型に対向配置される上型とを準備する工程と、
前記下型の下型成形面に対し、前記玉枠付レンズを構成するための玉枠を該玉枠の内部空間に該下型成形面が臨む位置関係で配置する玉枠配置工程と、
該玉枠配置工程後、前記下型成形面及び玉枠がそれぞれ加熱された状態で該下型成形面上に所定量の（前記レンズが得られる量の）溶融ガラス滴を滴下するガラス滴下工程と、
該ガラス滴下後、該ガラスが未だ加圧変形可能な温度にある間に前記下型と前記上型成形面を加熱した前記上型とを互いに対向させるとともに相対的に接近させて該ガラスを加圧成形することで対向する二つの光学機能面を有し、前記玉枠内に保持されたレンズを成形する加圧成形工程と、
該加圧成形工程後、該上下型による加圧を解除して玉枠付レンズを取り出すレンズ取出し工程とを含み、
前記玉枠の加熱は、前記加圧成形工程において該玉枠の温度が前記ガラス滴のガラス転移点温度（℃）から１００℃を差し引いた温度より高くなるように前記玉枠配置工程前又は（及び）該玉枠配置工程後に行う玉枠付レンズの製造方法を提供する。
【００１９】
【発明の実施の形態】
本発明の実施形態に係る玉枠付レンズの製造方法は、基本的に、次の工程を含むものである。すなわち、
（１）製造しようとする玉枠付レンズを構成するためのレンズの一つの光学機能面を成形するための下型成形面を有する下型と、該レンズのもう一つの光学機能面を成形するための上型成形面を有し、該下型に対向配置される上型とを準備する工程、
（２）前記下型の下型成形面に対し前記玉枠付レンズを構成するための玉枠を該玉枠の内部空間に該下型成形面が臨む所定位置関係で配置する玉枠配置工程、
（３）該玉枠配置工程後、前記下型成形面及び玉枠がそれぞれ所定温度に加熱された状態で該下型成形面上に所定量の（前記レンズが得られる量の）溶融ガラス滴を滴下するガラス滴下工程、
（４）該ガラス滴下後、該ガラスが未だ加圧変形可能な温度にある間に前記下型と前記上型成形面を所定温度に加熱した前記上型とを互いに対向させるとともに相対的に接近させて該ガラスを加圧成形することで対向する二つの光学機能面を有し、前記玉枠内に位置するレンズを成形する加圧成形工程、及び
（５）該加圧成形工程後、該上下型による加圧を解除して玉枠付レンズを取り出すレンズ取出し工程である。
【００２０】
前記玉枠の加熱は、前記加圧成形工程において該玉枠の温度が前記ガラス滴のガラス転移点温度（℃）から１００℃を差し引いた温度より高くなるように前記玉枠配置工程前又は（及び）該玉枠配置工程後に行う。
【００２１】
この玉枠付レンズの製造方法によると、旧来のように成形用レンズ素材を作製することは不要となり、また、かかるレンズ素材を成形用型とともに加熱、冷却する必要もないから、低コストで、生産性高く、玉枠付レンズを製造することができる。
【００２２】
また、この方法によると、加圧成形の段階ではなく、溶融ガラス滴の滴下の段階でガラスと玉枠とが一体化されるので、その一体化はその後の加圧成形工程における加圧成形条件に影響されにくく、加圧成形条件の変更、バラツキがあっても、安定したガラスと玉枠との結合が得られる。
【００２３】
レンズと玉枠との結合をより確実なものとするために、玉枠として内面にガラスを流入させる凹所を有する玉枠を採用してもよい。その場合、該凹所は、玉枠に形成した貫通孔で提供されるものや、点状の窪みにより提供されるものでもよいが、より確実にレンズと玉枠の結合を得るために、玉枠内周方向に形成された断面形状Ｕ字状、Ｖ字状等の溝形状の凹所としてもよい。
【００２４】
溝形状の凹所を採用する場合、それは玉枠内周方向に環状に形成されても、螺旋状等に形成されてもよい。かかる溝状凹所は玉枠への機械加工等により容易に形成できる。
いずれにしても、ガラスを流入させる凹所を玉枠内面に有する玉枠を採用することで、レンズに１０ｋｇの加重が加わってもレンズと玉枠との相対位置が変動しない両者の結合を得ることが可能になる。
【００２５】
滴下された溶融ガラス滴は、主に下型及び玉枠との接触面からの放熱によって冷却されるが、ガラスが未だ加圧変形可能な温度にある間に前記下型と所定温度に加熱した前記上型とを接近させて該ガラスを加圧成形するので、所望の厚み及び対向する二つの光学機能面を有するレンズを成形することができる。
【００２６】
また、玉枠を用いてレンズを成形するので、ガラス滴のレンズ外周部に相当する部分が玉枠により位置規制されるから、玉枠のサイズを選択することでレンズの小型化も可能である。
【００２７】
前記加圧成形工程における下型の温度、特に前記下型成形面の温度は、所望の玉枠付レンズを成形できる範囲の温度とすればよいが、必要以上に高くしすぎることは、ガラスと型面との融着を防ぐ観点及び型寿命の観点から好ましくない。一方、下型成形面の面形状、特に下型成形面のちう光学素子の光学機能面の有効径領域を形成するための領域（光学有効面領域）の面形状を精度良くガラスに転写させなければならない。これらの観点から、下型成形面の温度としては、ガラス転移点温度又はほぼ該温度（以下、これらを「実質上ガラス転移点温度」と総称することがある。）、或いは（ガラス転移点温度−５０℃）から（ガラス転移点温度＋１００℃）の範囲の温度とすることが望ましい。
【００２８】
前記加圧成形工程における上型、特に素子の光学機能面を形成する前記上型成形面の温度も、下型成形面の場合と同様の理由で、実質上ガラス転移点温度、或いは（ガラス転移点温度−５０℃）から（ガラス転移点温度＋１００℃）の範囲の温度とすることが望ましい。
【００２９】
既述のように、滴下された溶融ガラス滴は、主に下型及び玉枠との接触面からの放熱によって冷却されるが、このとき、玉枠の温度が低すぎると、玉枠との接触面からのガラスの放熱が早いためにガラス内部と玉枠との接触面近傍部との温度差が大きくなりすぎ、加圧成形の段階でガラスの外周部がすでに変形可能温度より低くなってしまい、外周部から割れ、かけが発生してしまう。
【００３０】
しかしここでは、前記のとおり、加圧成形工程においては玉枠の温度をガラス滴のガラス転移点温度（℃）から１００℃を差し引いた温度より高く設定するので、玉枠に接触して放熱するガラス滴部分の温度低下を抑制でき、加圧成形時の該部分の割れや欠け等の損傷を抑制することができ、それだけ良好な玉枠付レンズを得ることができる。
【００３１】
加圧成形工程における玉枠（特にその内周面）の温度は、ガラス外周部の割れ、欠けを抑えるという観点からは、高いほうが好ましい。
一方、前記下型成形面の温度は、前述の通り、型寿命等の観点から光学有効面領域の面形状を精度良くガラスに転移させるのに必要な温度より高温とすることは好ましくない。
このため、玉枠の温度として、例えば、前記下型成形面の温度〔（ガラス転移点温度−５０℃）から（ガラス転移点温度＋１００℃）の範囲の温度〕と同じか又はそれより高くする場合を挙げることができる。
【００３２】
いずれにしても、下型成形面及び上型成形面のそれぞれを加熱するための（それぞれの前記所定温度を得るための）温度制御における目標設定温度は一定に保ったまま前記玉枠配置工程、ガラス滴下工程、加圧成形工程及びレンズ取出し工程を実施することが可能である。そうすることで、玉枠付レンズ１個当たりの製造時間を大幅に短縮できる。
【００３３】
なお、ここで、「温度制御における目標設定温度は一定に保ったまま」とは、各工程実施中に、ガラスとの接触により下型成形面等の温度が変動することを防止しようとするものではなく、かかる温度変動については許容される。
玉枠の加熱は、玉枠配置工程前に行っても、玉枠配置工程後に行っても、玉枠配置の前後にわたり行ってもよいことは前記のとおりである。
【００３４】
いずれにしても、前記ガラス滴下工程において溶融ガラス滴を滴下するにあたり、該滴下路の途中に貫通細孔を形成した滴下量調整部材を配置し、該滴下量調整部材上にガラス滴を滴下衝突させることで該ガラス滴の少なくとも一部を微小滴として該部材細孔から押し出し前記下型成形面上に滴下させてもよい。そうすることで、微小なレンズの製造も可能となる。
【００３５】
光通信分野では、ガラス重量が１ｍｇから２０ｍｇの玉枠付レンズが要求されることがあるが、かかる小型の玉枠付レンズについても、上記滴下量調整部材を採用することで製造可能である。
【００３６】
以下図面を参照して光学素子製造の幾つかの例を説明する。
図１は製造しようとする玉枠付レンズ１０の断面図である。図２は玉枠付レンズ１０の製造に用いる金型の１例Ａの断面図である。図３は玉枠付レンズ１０の製造工程を示している。
【００３７】
図１に示す、製造しようとする玉枠付レンズ１０は、それには限定されないが、ここでは断面円形の玉枠Ｆにガラスレンズ１００を保持させたものである。レンズ１００は対向する二つの光学機能面１０１、１０２を有しているとともに、外周面が玉枠Ｆの内周面にしっかりと安定的に接触しており、レンズ外周部の一部（環状部）１０３が玉枠内周面に形成された断面Ｕ字状の環状溝ｆに入り込んでいる。かくしてレンズ１０と玉枠Ｆは確実強固に、安定した結合状態におかれている。
【００３８】
図２に示す金型Ａは下型１及び上型２、さらに玉枠保持部材３を備えている。下型１は、レンズ１００の一方の光学機能面１０１を形成するための、上方に向けられた、平面から見て円形の下型成形面１１を有している。下型１の下型成形面１１を含む頂部１２の外径は玉枠Ｆを丁度嵌合できるものであり、該頂部１２の下部には該頂部に嵌められる玉枠Ｆを載置する段部１２１が形成されている。下型１は図示省略の昇降駆動装置により昇降可能である。
【００３９】
玉枠保持部材３は左右の部分３１、３２に２分割されており、図示省略のガイド装置と駆動装置とで図中左右方向に接近離反可能であり、接近することで、前記下型頂部１２に嵌められる玉枠Ｆに抱くように接触することができる。すなわち、部分３１、３２のそれぞれは半円筒面を有し、該半円筒面で玉枠Ｆの外周面に接触することができる。
なお、玉枠保持部材は分割されていない一体のものでもよく、その場合は、部材内周面が玉枠外周面と嵌まり合う寸法のものにすればよい。
【００４０】
上型２は、レンズ１００の他方の光学機能面１０２を形成するための、下方に向けられた、下方から見て円形の上型成形面２１を有している。上型２は図示省略の昇降駆動装置により昇降可能であり、それにより上型成形面２１を含む下部２２が、下型頂部１２に嵌められる玉枠Ｆ内に出入できる。
【００４１】
下型１には下型成形面１１を加熱するための電気ヒータ１３が、上型２には上型成形面２１を加熱するための電気ヒータ２３が、玉枠保持部材３の左右部分３１、３２のそれぞれにも電気ヒータ３３がそれぞれ内蔵されている。これらヒータは温度調節装置４を用いて、下型１、上型２、玉枠保持部材３にそれぞれ設けられた温度センサ１４、２４、３４からの検出温度情報に基づきコントロールされ、下型成形面１１、上型成形面２１、玉枠Ｆのそれぞれについて設定された目標温度に向け該下型成形面、上型成形面、玉枠保持部材３の各半円筒面をそれぞれ加熱する。
【００４２】
温度調節装置４による温度制御における下型成形面１１及び上型成形面２１についての目標設定温度は後述するガラス滴のガラス転移点温度Ｔｇ程度、或いは（Ｔｇ−５０℃）から（Ｔｇ＋１００℃）の範囲の温度とされ、玉枠Ｆ、従って玉枠保持部材３の各半円筒面についての目標設定温度は（Ｔｇ−１００℃）より高温、例えば下型成形面１１についての目標設定温度と同一とされる。
【００４３】
次に金型Ａを用いる玉枠付レンズ１０の製造について図３を参照して説明する。
先ず、図３（Ａ）に示すように、下型頂部１２に玉枠Ｆを外嵌し、頂部段部１２１に設置する。次いで、該玉枠Ｆを玉枠保持部材３で左右から挟着する。その後に溶融ガラスＧを滴下させるノズル５を下型１の下型成形面１１の中央上方に配置し、図示省略の坩堝で溶融させた溶融ガラスＧをノズル５から所定量（レンズ１００を成形し得る量）下型成形面１１上に自然滴下する。
【００４４】
このとき、溶融ガラスＧの滴下に先立って、下型成形面１１をヒータ１３にてガラス滴Ｇのガラス転移点温度Ｔｇ程度、或いは（Ｔｇ−５０℃）から（Ｔｇ＋１００℃）の範囲の温度に加熱しておくとともに、玉枠保持部材３内蔵のヒータ３３にて玉枠Ｆを（Ｔｇ−１００℃）より高温、例えば下型成形面１１と同程度の温度に加熱しておく。なお、ガラス滴下後はノズル５を上型２の昇降に邪魔にならない位置へ退避させておく。
【００４５】
かかるノズル５からの自然落下によるガラス供給方法によると、レンズ１００を得るために滴下させるガラス滴重量のバラツキを±１ｍｇの範囲に抑えることが可能であり、それだけ精度のよいレンズを得ることができる。
【００４６】
溶融ガラスＧをノズル５から所定量下型成形面１１上に滴下すると、図３（Ｂ）に示すように、溶融ガラス滴ｇは下型成形面１１に衝突し、広がって玉枠Ｆの内面に接触するとともにガラスの一部が玉枠内周面の溝ｆに流入する。かくしてガラス滴ｇと玉枠Ｆとが一体化され、両者の結合が確実なものとされる。
【００４７】
その後図３（Ｃ）に示すように、ガラスｇが未だ加圧変形可能な温度にある間に、予め下型１と同程度の温度に加熱しておいた上型２を玉枠Ｆ内に下降させ、ガラスｇを上下型１、２間で加圧してレンズ１００の対向する光学機能面１０１、１０２を加圧成形し、且つ、ガラスｇの厚みをレンズ１００の厚みとしてレンズ１００を形成する。
【００４８】
このとき、ガラスｇのうち滴下の段階で玉枠内面と接触しなかった部分が加圧成形時においても玉枠内面と接触せず、ガラス外周部に凹み等として残る場合があり得るが、かかる部分は玉枠Ｆの内面より外側へはみ出ることはないので、支障はない。
その後は、図３（Ｄ）に示すように、上型２を上昇させ、出来上がった玉枠付レンズ１０を下型１から取り出す。
【００４９】
以上の玉枠付レンズ製造工程は、温度調節装置４による温度制御における下型成形面１１、上型成形面２１及び玉枠保持部材３（従って玉枠Ｆ）それぞれについての目標設定温度を一定としたままで繰り返し実施でき、それにより効率良く玉枠付レンズ１０を製造することができる。
【００５０】
前記ノズル５からの自然落下によるガラス滴下では、通常、１００ｍｇ以下の重量のガラス滴を滴下させるのは困難である。そこで、少量のガラス滴でもってより小型の玉枠付レンズを作る場合には、図４に示すように、溶融ガラス滴ｇを滴下するにあたり、該滴下路の途中に、上方へ拡広したテーパ孔６１に続く貫通細孔６２を形成した滴下量調整部材６を配置し、該部材６上にガラス滴ｇを滴下衝突させることで該ガラス滴の少なくとも一部を微小滴ｇ’として細孔６２から押し出し、これを下型１上に滴下させてもよい。
【００５１】
かかる滴下量調整部材６を採用することで、ガラス滴重量のバラツキを抑えることが一層容易となり、例えば、下型１上に滴下するガラス重量が１０ｍｇという少量の場合でも、ガラス滴重量のバラツキを±０．１ｍｇの範囲に抑えることができ、それだけ精度のよい小型レンズを得ることができる。
【００５２】
図５は玉枠付レンズの他の例１０’を示している。この玉枠付レンズ１０’は図１の玉枠付レンズ１０において、玉枠Ｆ内周面における溝を断面Ｖ字状の溝ｆ’として２本形成したものである。従ってレンズ１００’の一部１０３’がこれら２本の溝ｆ’に入り込んでいる。その他の点は図１に示す玉枠付レンズ１０と同じである。かかる玉枠付レンズ１０’も前記と同様の方法で製造することができる。
【００５３】
次に玉枠付レンズ製造の実施例について説明する。
以下の実施例ではいずれもガラス材料、玉枠材料は以下のものである。金型は図２に示すタイプのものを用いた。
使用ガラス材料：リン酸塩系ガラス
ガラス転移点温度Ｔｇ：４３２℃
玉枠材料：ＳＵＳ４３０
【００５４】
（実施例１）

玉枠付レンズ取り出しまでこれら目標設定温度は一定に維持した。
ガラス滴下は上記ガラスを１１００℃で溶融させノズル温度を９００℃として、図４に示す構成の滴下量調整部材を用いて１０ｍｇのガラス滴を該部材下５ｍｍの距離を下型成形面上に滴下させた。
【００５５】
下型成形面上への溶融ガラス滴下後、ガラスが変形可能温度にある間（滴下から３秒後）に上下金型でガラスを加圧成形した。かくして、図１に示すと同様の玉枠付レンズを得ることができた。
【００５６】
上下の金型及び玉枠保持部材の制御温度（設定目標温度）を一定に保ったまま、さらに玉枠配置、ガラス滴下、加圧成形及び取出しの各工程を繰り返し（各玉枠についてはその都度加熱し）、先のものも含め合計１０個の玉枠付レンズを製造したところ、いずれのレンズにも割れ、欠け等の損傷は認められなかった。また、レンズに１０ｋｇの加重加えてもレンズと玉枠の相対的位置変動は認められなかった。
【００５７】
（実施例２）

玉枠付レンズ取り出しまでこれら目標設定温度は一定に維持した。
ガラス滴下は上記ガラスを１１００℃で溶融させノズル温度を９００℃として、図４に示す構成の滴下量調整部材を用いて約９ｍｇのガラス滴を該部材下５ｍｍの距離を下型成形面上に滴下させた。
【００５８】
下型成形面上への溶融ガラス滴下後、ガラスが変形可能温度にある間（滴下から２秒後）に上下金型でガラスを加圧成形した。
図５に示すと同様の玉枠付レンズを得ることができた。
【００５９】
上下の金型及び玉枠保持部材の制御温度（設定目標温度）を一定に保ったまま、さらに玉枠配置、ガラス滴下、加圧成形及び取出しの各工程を繰り返し（各玉枠についてはその都度加熱し）、先のものも含め合計１０個の玉枠付レンズを製造したところ、いずれのレンズにも割れ、欠け等の損傷は認められなかった。また、レンズに１０ｋｇの加重加えてもレンズと玉枠の相対的位置変動は認められなかった。
【００６０】
【発明の効果】
以上説明したように本発明によると、レンズ材料の成形により玉枠と一体化されたレンズを形成する玉枠付レンズの製造方法であって、かかる玉枠付レンズを低コストで、生産性高く製造でき、レンズの小型化にも対応できる玉枠付レンズの製造方法を提供することができる。
【図面の簡単な説明】
【図１】玉枠付レンズの１例の断面図である。
【図２】玉枠付レンズ製造に用いる上下金型及び玉枠保持部材の断面図である。
【図３】図１に示す玉枠付レンズの製造工程を示す図である。
【図４】ガラス滴下量の調整部材を用いる例を示す図である。
【図５】玉枠付レンズの他の例の断面図である。
【符号の説明】
１０、１０’玉枠付レンズ
１００レンズ
１０１、１０２レンズの光学機能面
Ｄレンズ外径
Ａ金型
１下型
１１下型成形面
１２下型頂部
１３ヒータ
１４温度センサ
２上型
２１上型成形面
２２上型下部
２３ヒータ
２４温度センサ
３玉枠保持部材
３１、３２部材３の半割り部分
３３ヒータ
３４温度センサ
４温度調節装置
５ノズル
Ｇ溶融ガラス
ｇ、ｇ’溶融ガラス滴
６滴下量調整部材
６１テーパ孔
６２貫通細孔[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method of manufacturing a lens with a ball frame, and more particularly to a method of manufacturing a lens with a ball frame that forms a lens integrated with the ball frame by molding a lens material.
[0002]
[Prior art]
A so-called lens with a lens frame in which a lens is held in a ring-shaped or cylindrical lens frame is employed in various optical device fields and various technical fields including optical devices. For example, in the field of optical communication, it is used to introduce light from an optical fiber into an optical sensor or to guide laser light to an optical fiber.
There are various types of lenses with a ball frame, depending on the mode of coupling between the lens and the ball frame. One of them is a ball formed such that the lens is integrated with the ball frame by molding the lens material. There is a framed lens.
[0003]
For example, Japanese Patent Publication No. 63-53522 discloses a method for manufacturing such a lens with a ball frame in which a lens material is disposed in a lens barrel having a plurality of through holes formed on a side surface, and a part of the lens material is used. It is disclosed that a lens held by the lens barrel is formed by pressure-forming the lens material so as to flow into the through-hole and solidify. Further, Japanese Patent Application Laid-Open No. Hei 3-237023 discloses that a glass material for molding is arranged in a hole of a lens holder, and the lens is held by the glass material by molding the glass material.
[0004]
The lens material disposed in the lens barrel or lens holder in the method disclosed in these publications is made in advance to a predetermined weight and shape, and the lens material is heated together with a molding die, and after molding, It is cooled to around room temperature together with the mold for removal.
[0005]
On the other hand, as a method of manufacturing a lens, the following method, which is completely different from a method in which a lens material manufactured to a predetermined weight and shape is heated and molded together with a mold and then cooled together with the mold to take out the lens, is proposed. Have been.
[0006]
That is, Japanese Patent Application Laid-Open No. 4-16414 discloses that a predetermined amount of molten glass droplet is dropped on a molding die from a nozzle tip, and a lens is applied by the molding die while the dropped glass droplet is still at a deformable temperature. A method of pressing is disclosed.
[0007]
Further, in the molding method disclosed in JP-A-4-16414, it was difficult to obtain a fine molten glass droplet having a size of 100 mg or less due to a natural drop from a nozzle. JP-A-154834 discloses a method of disposing a drop amount adjusting member having a through-hole formed in the middle of a dropping path of molten glass from a nozzle, and causing at least the glass droplet to collide with the drop amount adjusting member. It discloses that a minute glass droplet is obtained by extruding a part of the member as a minute droplet from the pores of the member.
[0008]
[Patent Literature 1] Japanese Patent Publication No. 63-53522 [Patent Literature 2] Japanese Patent Application Laid-Open No. Hei 3-237023 [Patent Literature 3] Japanese Patent Application Laid-Open No. Hei 4-164414 [Patent Literature 4] Japanese Patent Application Laid-Open No. 2002-154834 ]
[Problems to be solved by the invention]
However, in the method of manufacturing a lens with a lens barrel disclosed in Japanese Patent Publication No. 63-53522 and the method of manufacturing a lens with a holder disclosed in Japanese Patent Application Laid-Open No. 3-237022, the predetermined weight and It is indispensable to accurately produce the lens material for molding, and it is necessary to strictly control the weight of the lens material, and it takes a long time to heat and cool the lens material and the mold. Therefore, it is difficult to reduce the cost of the lens.
[0010]
In this regard, according to the lens manufacturing method disclosed in JP-A-4-16414 and JP-A-2002-154834, since a molten glass droplet is spontaneously dropped from the nozzle tip, a lens material that is expensive to manufacture is required. In addition, the step of heating the lens material and the mold from room temperature and cooling after molding is not required, and the lens manufacturing time can be greatly reduced. As a result, the lens manufacturing cost can be significantly reduced and the productivity of the lens can be increased as compared with a method in which the molding lens material is heated and cooled together with the mold and molded.
[0011]
However, JP-A-4-16414 and JP-A-2002-154834 do not disclose any application of the disclosed lens manufacturing method to a method of manufacturing a lens with a ball frame.
[0012]
Therefore, the present invention is a method for manufacturing a lens with a lens frame which forms a lens integrated with the lens frame by molding a lens material, and it is possible to manufacture such a lens with a lens frame at low cost and with high productivity. It is an object of the present invention to provide a method for manufacturing a lens with a ball frame that can respond to downsizing.
[0013]
[Means for Solving the Problems]
The inventors of the present invention have conducted various studies to solve the above problems, and have completed the present invention by focusing on the following points.
First, as for the lens itself, a lens material for molding is manufactured by adopting a method basically similar to the method of manufacturing a lens by molding molten glass droplets disclosed in Japanese Patent Application Laid-Open No. 4-16414. Is unnecessary, and it is not necessary to heat and cool such a lens material together with a molding die, so that a lens can be manufactured at low cost and with high productivity.
[0014]
Regarding the point that the lens is held in the ball frame, in forming the glass droplet under pressure, the ball frame is placed in advance with respect to the lower mold in a predetermined positional relationship in which the molding surface of the lower mold faces the internal space of the ball frame. In this state, if a molten glass droplet is dropped on the lower mold, the glass droplet collides with the lower mold and spreads, and comes into contact with the ball frame. Is held in a ball frame, whereby a lens with a ball frame can be obtained.
[0015]
In addition, according to such a method, the glass and the ball frame are integrated at the stage of dropping the molten glass droplet, not at the stage of pressure molding, so that it is hardly affected by the conditions of the subsequent pressure molding. Thus, a stable connection between the glass and the ball frame can be obtained.
[0016]
Further, the dropped molten glass droplet is cooled mainly by heat radiation from the contact surface with the lower mold and the rim, but the temperature of the rim is subtracted by 100 ° C. from the glass transition temperature (° C.) of the glass droplet. If the temperature is higher than the temperature, it is possible to suppress a decrease in the temperature of the glass droplet portion that radiates heat by contacting the ball frame, and it is possible to suppress damage such as cracking or chipping of the portion during pressure molding. You can get a lens.
[0017]
Further, when the lens is molded using the lens frame, the position corresponding to the lens outer peripheral portion of the glass droplet is regulated by the lens frame, so that the edge formed in a free state without regulation does not occur. Therefore, the size of the lens can be reduced by selecting the size of the ball frame and the amount of the dropped glass.
[0018]
Focusing on the above points, the present invention
A lower mold having a lower mold forming surface for molding one optical functional surface of a lens for forming a lens with a ball frame to be manufactured, and an upper mold for molding another optical functional surface of the lens. A step of preparing an upper mold having a mold forming surface and being arranged to face the lower mold,
With respect to the lower mold forming surface of the lower mold, a ball frame arranging step of arranging a ball frame for constituting the lens with a ball frame in a positional relationship where the lower mold forming surface faces the internal space of the ball frame,
A glass dropping step of dropping a predetermined amount (amount of the lens obtained) of molten glass onto the lower mold forming surface while the lower mold forming surface and the ball frame are each heated after the ball forming step; When,
After the dropping of the glass, the lower mold and the upper mold heated on the upper mold forming surface are opposed to each other and relatively approached while the glass is still at a temperature at which the glass can be deformed under pressure, and the glass is heated. Having two optical functional surfaces facing each other by pressure molding, a pressure molding step of molding a lens held in the ball frame,
After the pressure molding step, a lens taking out step of taking out the lens with the ball frame by releasing the pressure by the upper and lower molds,
The heating of the bead frame is performed before or after the bead placement step such that the temperature of the bead frame is higher than the temperature obtained by subtracting 100 ° C. from the glass transition temperature (° C.) of the glass droplet in the pressure forming step. And / or) a method of manufacturing a lens with a ball frame to be performed after the ball frame arranging step.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
A method for manufacturing a lens with a ball frame according to an embodiment of the present invention basically includes the following steps. That is,
(1) A lower mold having a lower mold forming surface for molding one optical functional surface of a lens for forming a lens with a lens frame to be manufactured, and another optical functional surface of the lens is molded. Having an upper mold forming surface for, and preparing an upper mold disposed to face the lower mold,
(2) A ball frame arranging step of arranging a ball frame for forming the lens with a ball frame on the lower mold forming surface of the lower mold in a predetermined positional relationship such that the lower mold forming surface faces the internal space of the ball frame. ,
(3) After the step of disposing the lens frame, a predetermined amount of molten glass droplets (an amount that can obtain the lens) is formed on the lower mold forming surface while the lower mold forming surface and the ball frame are each heated to a predetermined temperature. A glass dripping step,
(4) After the glass is dropped, the lower mold and the upper mold whose upper mold molding surface is heated to a predetermined temperature are opposed to each other and relatively approached while the glass is still at a temperature at which the glass can be deformed under pressure. And pressing the glass to form a lens having two optical functional surfaces facing each other and forming a lens located in the lens frame. (5) After the pressure forming step, This is a lens taking-out step of releasing the pressure by the upper and lower molds and taking out the lens with the ball frame.
[0020]
The heating of the bead frame is performed before or after the bead placement step such that the temperature of the bead frame is higher than the temperature obtained by subtracting 100 ° C. from the glass transition temperature (° C.) of the glass droplet in the pressure forming step. And) after the ball frame arrangement step.
[0021]
According to this method of manufacturing a lens with a ball frame, it is not necessary to prepare a molding lens material as in the past, and it is not necessary to heat and cool such a lens material together with a molding die. It is possible to manufacture a lens with a ball frame with high productivity.
[0022]
In addition, according to this method, the glass and the ball frame are integrated at the stage of dropping the molten glass droplet instead of at the stage of pressure molding, and the integration is performed under the pressure molding conditions in the subsequent pressure molding process. And stable bonding between the glass and the ball frame can be obtained even if the pressure molding conditions are changed or varied.
[0023]
In order to make the connection between the lens and the ball frame more reliable, a ball frame having a recess into which glass flows into the inner surface may be employed as the ball frame. In this case, the recess may be provided by a through hole formed in the lens frame or may be provided by a point-like depression. It may be a groove-shaped recess such as a U-shaped or V-shaped cross section formed in the inner circumferential direction of the frame.
[0024]
When a groove-shaped recess is employed, it may be formed in a ring shape in the inner circumferential direction of the ball frame, or may be formed in a spiral shape or the like. Such a groove-shaped recess can be easily formed by machining the ball frame.
In any case, by adopting a ball frame having a concave portion into which the glass flows in on the inner surface of the ball frame, it is possible to obtain a connection between the lens and the lens frame in which the relative position of the lens frame does not fluctuate even when a load of 10 kg is applied to the lens. It becomes possible.
[0025]
The dropped molten glass droplet is cooled mainly by heat radiation from the contact surface with the lower mold and the ball frame, but was heated to a predetermined temperature with the lower mold while the glass was still at a temperature capable of being deformed under pressure. Since the glass is pressed under the close proximity of the upper mold, a lens having a desired thickness and two opposing optical functional surfaces can be formed.
[0026]
In addition, since the lens is formed using the lens frame, the position of the glass droplet corresponding to the outer peripheral portion of the lens is regulated by the lens frame. Therefore, the size of the lens frame can be reduced by selecting the size of the lens frame. .
[0027]
The temperature of the lower mold in the pressure molding step, in particular, the temperature of the lower mold forming surface may be a temperature within a range in which a desired lens with a rim can be molded. It is not preferable from the viewpoint of preventing fusion with the mold surface and the viewpoint of mold life. On the other hand, the surface shape of the lower mold forming surface, in particular, the surface shape of the area for forming the effective diameter area of the optical functional surface of the optical element (optical effective surface area) following the lower mold forming surface must be accurately transferred to glass. Must. From these viewpoints, the temperature of the lower mold forming surface is the glass transition point temperature or almost the same (hereinafter, these may be collectively referred to as “substantially the glass transition point temperature”), or (the glass transition point temperature). The temperature is desirably in the range of (−50 ° C.) to (glass transition temperature + 100 ° C.).
[0028]
The temperature of the upper mold in the pressure molding step, particularly the temperature of the upper mold forming surface that forms the optically functional surface of the element, is also substantially the same as the glass transition point temperature or (glass transition temperature) for the same reason as in the case of the lower mold forming surface. The temperature is desirably in the range of (point temperature −50 ° C.) to (glass transition temperature + 100 ° C.).
[0029]
As described above, the dropped molten glass droplet is cooled mainly by heat radiation from the contact surface with the lower mold and the ball frame. At this time, when the temperature of the ball frame is too low, Due to the rapid heat dissipation of the glass from the contact surface, the temperature difference between the inside of the glass and the vicinity of the contact surface with the ball frame becomes too large, and the outer peripheral portion of the glass is already lower than the deformable temperature at the stage of pressure molding. As a result, cracks and cracks occur from the outer peripheral portion.
[0030]
However, here, as described above, in the pressure molding step, the temperature of the ball frame is set higher than the temperature obtained by subtracting 100 ° C. from the glass transition point temperature (° C.) of the glass droplet, so that heat is released by contacting the ball frame. The temperature drop of the glass droplet portion can be suppressed, and damage such as cracking or chipping of the portion at the time of pressure molding can be suppressed, and a lens with a good rim can be obtained accordingly.
[0031]
The temperature of the ball frame (especially its inner peripheral surface) in the pressure molding step is preferably higher from the viewpoint of suppressing cracking and chipping of the outer peripheral portion of the glass.
On the other hand, as described above, it is not preferable to set the temperature of the lower mold forming surface to be higher than the temperature required for accurately transferring the surface shape of the optically effective surface region to glass from the viewpoint of the mold life and the like.
For this reason, the temperature of the bead frame is, for example, the same as or higher than the temperature of the lower mold forming surface [the temperature in the range of (glass transition temperature −50 ° C.) to (glass transition temperature + 100 ° C.)]. Cases can be mentioned.
[0032]
In any case, the target frame setting step in the temperature control for heating each of the lower mold forming surface and the upper mold forming surface (to obtain the respective predetermined temperatures) is kept constant, It is possible to perform a glass dropping step, a pressure forming step, and a lens removing step. By doing so, the manufacturing time per one lens with a ball frame can be greatly reduced.
[0033]
Here, “the target set temperature in the temperature control is kept constant” means to prevent the temperature of the lower mold forming surface or the like from fluctuating due to contact with glass during each process. Instead, such temperature fluctuations are allowed.
As described above, the heating of the ball frame may be performed before the ball frame arranging step, after the ball frame arranging step, or before and after the ball frame arranging step.
[0034]
In any case, when the molten glass droplet is dropped in the glass dropping step, a drop amount adjusting member having a through-hole formed therein is disposed in the middle of the dropping path, and the glass droplet is dropped on the drop amount adjusting member. By doing so, at least a part of the glass droplet may be extruded as a minute droplet from the pores of the member and dropped on the lower mold forming surface. By doing so, it becomes possible to manufacture minute lenses.
[0035]
In the optical communication field, a lens with a ball frame having a glass weight of 1 mg to 20 mg is sometimes required, but such a small lens with a ball frame can be manufactured by employing the above-described dripping amount adjusting member.
[0036]
Hereinafter, some examples of manufacturing an optical element will be described with reference to the drawings.
FIG. 1 is a sectional view of a lens with a ball frame 10 to be manufactured. FIG. 2 is a sectional view of an example A of a mold used for manufacturing the lens 10 with a ball frame. FIG. 3 shows a manufacturing process of the lens 10 with a ball frame.
[0037]
Although the lens 10 with a ball frame to be manufactured shown in FIG. 1 is not limited to this, here, a glass frame 100 is held by a ball frame F having a circular cross section. The lens 100 has two opposing optical

functional surfaces

101 and 102, and the outer peripheral surface is firmly and stably in contact with the inner peripheral surface of the lens frame F, and a part (annular portion) of the outer peripheral portion of the lens. ) 103 penetrates into an annular groove f having a U-shaped cross section formed on the inner peripheral surface of the ball frame. Thus, the lens 10 and the lens frame F are securely and firmly connected.
[0038]
The mold A shown in FIG. 2 includes a lower mold 1 and an upper mold 2, and a ball frame holding member 3. The lower die 1 has a lower die forming surface 11 that is upwardly directed and is circular when viewed from above, for forming one optical function surface 101 of the lens 100. The outer diameter of the top portion 12 including the lower mold forming surface 11 of the lower mold 1 is such that the ball frame F can be just fitted, and a step portion on which the ball frame F to be fitted on the top portion is placed below the top portion 12. 121 are formed. The lower die 1 can be moved up and down by a lifting drive device (not shown).
[0039]
The frame holding member 3 is divided into left and

right portions

31 and 32, and can be approached to and separated from each other in the left-right direction by a guide device and a driving device (not shown). Can be brought into contact with the ball frame F to be fitted into the frame. That is, each of the

portions

31 and 32 has a semi-cylindrical surface, and the semi-cylindrical surface can contact the outer peripheral surface of the frame F.
In addition, the ball frame holding member may be an integral body that is not divided, and in that case, the member inner peripheral surface may have a size that fits with the ball frame outer peripheral surface.
[0040]
The upper mold 2 has an upper mold forming surface 21 facing downward and circular as viewed from below, for forming the other optical function surface 102 of the lens 100. The upper mold 2 can be moved up and down by an elevation drive device (not shown), so that the lower portion 22 including the upper mold forming surface 21 can enter and exit the ball frame F fitted to the lower mold top 12.
[0041]
The lower mold 1 has an electric heater 13 for heating the lower mold forming surface 11, the upper mold 2 has an electric heater 23 for heating the upper mold forming surface 21, and the left and right portions 31 of the ball frame holding member 3. Each of the electric heaters 32 has a built-in electric heater 33. These heaters are controlled using a temperature control device 4 based on detected temperature information from

temperature sensors

14, 24, 34 provided on the lower die 1, the upper die 2, and the frame holding member 3, respectively. 11, the lower mold forming surface, the upper mold forming surface, and the respective semi-cylindrical surfaces of the ball frame holding member 3 are heated to target temperatures set for each of the upper mold forming surface 21 and the ball frame F.
[0042]
The target set temperature for the lower mold surface 11 and the upper mold surface 21 in the temperature control by the temperature controller 4 is about the glass transition temperature Tg of a glass droplet described later, or (Tg−50 ° C.) to (Tg + 100 ° C.). The target set temperature for the ball frame F, and thus for each semi-cylindrical surface of the ball frame holding member 3 is higher than (Tg-100 ° C.), for example, the same as the target set temperature for the lower mold forming surface 11. Is done.
[0043]
Next, the manufacture of the lens 10 with a ball frame using the mold A will be described with reference to FIG.
First, as shown in FIG. 3A, the lens frame F is externally fitted to the lower mold top 12 and is set on the top step 121. Next, the ball frame F is clamped by the ball frame holding member 3 from left and right. Thereafter, a nozzle 5 for dropping the molten glass G is disposed above the center of the lower mold forming surface 11 of the lower mold 1, and the molten glass G melted in a crucible (not shown) is discharged from the nozzle 5 by a predetermined amount (to form the lens 100). (Amount to be obtained) Natural drops are dropped on the lower mold forming surface 11.
[0044]
At this time, prior to the dropping of the molten glass G, the lower mold surface 11 is heated by the heater 13 to a glass transition point temperature Tg of the glass droplet G or a temperature in the range of (Tg−50 ° C.) to (Tg + 100 ° C.). While being heated, the ball frame F is heated to a temperature higher than (Tg−100 ° C.), for example, a temperature approximately equal to that of the lower mold forming surface 11 by the heater 33 built in the ball frame holding member 3. After the glass is dropped, the nozzle 5 is retracted to a position where it does not hinder the vertical movement of the upper mold 2.
[0045]
According to the glass supply method by the natural fall from the nozzle 5, the variation of the weight of the glass droplet dropped to obtain the lens 100 can be suppressed within the range of ± 1 mg, and a lens with high accuracy can be obtained. .
[0046]
When a predetermined amount of the molten glass G is dropped from the nozzle 5 onto the lower mold forming surface 11, the molten glass droplet g collides with the lower mold forming surface 11 and spreads, as shown in FIG. And a part of the glass flows into the groove f on the inner peripheral surface of the lens frame. Thus, the glass drop g and the ball frame F are integrated, and the connection between the two is ensured.
[0047]
Thereafter, as shown in FIG. 3 (C), while the glass g is still at a temperature capable of being deformed under pressure, the upper mold 2 previously heated to the same temperature as the lower mold 1 is placed in the frame F. Then, the glass g is pressed between the upper and

lower molds

1 and 2 to form the opposing optical

functional surfaces

101 and 102 of the lens 100 under pressure, and the lens 100 is formed with the thickness of the glass g as the thickness of the lens 100. .
[0048]
At this time, the portion of the glass g that did not contact the inner surface of the rim at the stage of dropping does not contact the inner surface of the rim even at the time of pressure molding, and may remain as a dent or the like in the outer peripheral portion of the glass. Since the portion does not protrude outside the inner surface of the ball frame F, there is no problem.
Thereafter, as shown in FIG. 3D, the upper mold 2 is raised, and the completed lens 10 with a ball frame is taken out of the lower mold 1.
[0049]
In the manufacturing process of the lens with the lens frame described above, the target set temperatures of the lower mold forming surface 11, the upper mold molding surface 21, and the lens frame holding member 3 (therefore, the lens frame F) in the temperature control by the temperature controller 4 are set to be constant. It can be repeatedly carried out as it is, so that the lens 10 with the ball frame can be manufactured efficiently.
[0050]
In the case of dropping glass by natural dropping from the nozzle 5, it is usually difficult to drop a glass drop having a weight of 100 mg or less. Therefore, when a smaller lens with a lens frame is to be manufactured using a small amount of glass droplets, as shown in FIG. A drop amount adjusting member 6 having a through-hole 62 formed following the hole 61 is disposed, and a glass droplet g is dropped and collided on the member 6 to convert at least a part of the glass droplet into a minute droplet g ′. , And may be dropped on the lower mold 1.
[0051]
By employing such a dripping amount adjusting member 6, it is easier to suppress the variation in the weight of the glass droplets. For example, even if the weight of the glass dropped on the lower mold 1 is as small as 10 mg, the variation in the weight of the glass droplets can be reduced. It can be suppressed to the range of ± 0.1 mg, and a small lens with high accuracy can be obtained.
[0052]
FIG. 5 shows another example 10 'of a lens with a ball frame. This lens 10 ′ with a ball frame is obtained by forming two grooves on the inner peripheral surface of the lens frame F in the lens 10 with a ball frame of FIG. 1 as grooves f ′ having a V-shaped cross section. Therefore, a part 103 'of the lens 100' enters these two grooves f '. The other points are the same as those of the lens 10 with a ball frame shown in FIG. Such a lens 10 ′ with a ball frame can also be manufactured by the same method as described above.
[0053]
Next, an example of manufacturing a lens with a ball frame will be described.
In each of the following examples, the glass material and the ball frame material are as follows. The mold used was of the type shown in FIG.
Glass material used: phosphate glass transition temperature Tg: 432 ° C
Ball frame material: SUS430
[0054]
(Example 1)

These target set temperatures were kept constant until the lens with the bezel was taken out.
For the glass dropping, the above glass is melted at 1100 ° C., the nozzle temperature is set to 900 ° C., and a 10 mg glass drop is dropped on the lower mold forming surface at a distance of 5 mm below the member using a drop amount adjusting member having a configuration shown in FIG. I let it.
[0055]
After the molten glass was dropped onto the lower mold forming surface, while the glass was at a deformable temperature (3 seconds after the dropping), the glass was pressure-formed using upper and lower dies. Thus, a lens with a ball frame similar to that shown in FIG. 1 was obtained.
[0056]
While maintaining the control temperature (set target temperature) of the upper and lower molds and the frame holding member at a constant level, the processes of ball frame placement, glass dripping, pressure molding, and removal are further repeated (for each ball frame, Heating) to produce a total of ten lensed lenses including the previous ones. No damage such as cracking or chipping was observed in any of the lenses. Further, even when a weight of 10 kg was applied to the lens, no relative positional change between the lens and the frame was observed.
[0057]
(Example 2)

These target set temperatures were kept constant until the lens with the bezel was taken out.
The glass dripping is performed by melting the above glass at 1100 ° C., setting the nozzle temperature to 900 ° C., and using a dripping amount adjusting member having a configuration shown in FIG. It was dropped.
[0058]
After the molten glass was dropped onto the lower mold forming surface, while the glass was at a deformable temperature (2 seconds after the dropping), the glass was pressure-formed using upper and lower dies.
A lens with a ball frame similar to that shown in FIG. 5 was obtained.
[0059]
While maintaining the control temperature (set target temperature) of the upper and lower molds and the frame holding member at a constant level, the processes of ball frame placement, glass dripping, pressure molding, and removal are further repeated (for each ball frame, Heating) to produce a total of ten lensed lenses including the previous ones. No damage such as cracking or chipping was observed in any of the lenses. Further, even when a weight of 10 kg was applied to the lens, no relative positional change between the lens and the frame was observed.
[0060]
【The invention's effect】
As described above, according to the present invention, there is provided a method for manufacturing a lens with a ball frame which forms a lens integrated with a ball frame by molding a lens material. It is possible to provide a method of manufacturing a lens with a ball frame which can be manufactured and can cope with downsizing of the lens.
[Brief description of the drawings]
FIG. 1 is a sectional view of an example of a lens with a ball frame.
FIG. 2 is a sectional view of an upper and lower mold and a ball frame holding member used for manufacturing a lens with a ball frame.
FIG. 3 is a view showing a manufacturing process of the lens with a ball frame shown in FIG. 1;
FIG. 4 is a diagram illustrating an example in which an adjusting member for adjusting a glass drop amount is used.
FIG. 5 is a sectional view of another example of the lens with a ball frame.
[Explanation of symbols]
10, 10 'lens with lens frame 100

Lens

101, 102 Optical function surface of lens D Lens outer diameter A Mold 1 Lower die 11 Lower die forming surface 12 Lower die top 13 Heater 14 Temperature sensor 2 Upper die 21 Upper die forming surface Reference Signs List 22 Upper die lower part 23 Heater 24 Temperature sensor 3 Ball

frame holding members

31, 32 Half part 33 of member 3 Heater 34 Temperature sensor 4 Temperature controller 5 Nozzle G Molten glass g, g 'Molten glass droplet 6 Dropping amount adjusting member 61 Taper hole 62 Through hole

Claims

A lower mold having a lower mold forming surface for molding one optical functional surface of a lens for forming a lens with a ball frame to be manufactured, and an upper mold for molding another optical functional surface of the lens. A step of preparing an upper mold having a molding surface and facing the lower mold,
With respect to the lower mold forming surface of the lower mold, a ball frame arranging step of arranging a ball frame for constituting the lens with a ball frame in a positional relationship in which the lower mold forming surface faces the internal space of the ball frame,
After the ball frame disposing step, a glass dropping step of dropping an amount of the molten glass droplet that allows the lens to be obtained on the lower mold forming surface while the lower mold forming surface and the ball frame are each heated.
After the glass is dropped, the lower mold and the upper mold whose upper mold molding surface is heated are opposed to each other and relatively approached while the glass is still at a temperature at which the glass can be deformed under pressure, and the glass is heated. Having two optical functional surfaces opposed by pressure molding, a pressure molding step of molding a lens held in the ball frame,
After the pressure molding step, a lens taking out step of taking out the lens with the ball frame by releasing the pressure by the upper and lower molds,
The heating of the bead frame is performed before or after the bead placement step such that the temperature of the bead frame is higher than the temperature obtained by subtracting 100 ° C. from the glass transition temperature (° C.) of the glass droplet in the pressure forming step. And) a method of manufacturing a lens with a ball frame, which is performed after the ball frame arranging step.

While maintaining the target set temperature in the temperature control for heating the lower mold forming surface and the upper mold forming surface respectively, the ball frame disposing step, the glass dropping step, the pressure forming step, and the lens removing step are performed. A method for manufacturing a lens with a ball frame according to claim 1.

The method for manufacturing a lens with a ball frame according to claim 1 or 2, wherein a ball frame having a concave portion into which glass flows is provided on the inner surface of the ball frame as the ball frame.

The method for manufacturing a lens with a ball frame according to any one of claims 1 to 3, wherein the recess on the inner surface of the ball frame is a groove-shaped recess formed in an inner circumferential direction of the ball frame.

Upon dropping the molten glass droplet in the glass dropping step, a drop amount adjusting member having a through-hole formed in the middle of the dropping path is arranged, and the glass droplet is dropped and collided on the drop amount adjusting member. The method for manufacturing a lens with a ball frame according to any one of claims 1 to 4, wherein at least a part of the glass droplet is extruded as a minute droplet from the pores of the member and dropped on the lower mold forming surface.