JP2004513388A - Wide field spherical lens and protective eyewear - Google Patents

Abstract

The present invention provides a novel ophthalmic lens element (402, 404) and eye with properties that provide a wide field of view, low distortion, improved astigmatism when needed, and enhanced eye protection. Ware (400). The series of lens elements has a steeply curved spherical reference surface. The series of edged lenses has an almost consistent aperture size, shape and hollow depth over the normal prescription range. Novel sunglasses, laser protective eyewear, and lens edging, coatings, and frames are included in the present invention.

Description

ここで、Ｒ（θ）はθ子午線に沿った曲率半径であり、ｒ＝√（Ｘ^２＋Ｙ^２）である。Ｒ（０）およびＲ（９０）の値は所望の接線度数で固定され、中間角度における度数はこれらの限界値に対して補間法を適用することにより決定される。補間の形式は、上記の度数プロファイルの形式がほぼ正弦波状になるという認識から来る。従って、Ｒ（θ）についての良好な１次近似は下記の通りとなるであろう。
【００７０】
【数２】

ここで、Ｐは接線度数であり、ｎは度数を曲率に変換するのに必要な屈折率である。矢状挙動に対する支配をさらに加えるため、補間にさらなるフーリエ項を追加することができる。接線挙動に対する支配をさらに増すため、度数はｒにおける多項式となり得る。単純な面の場合、さらなる自由度は要求されない。図１３Ａ、Ｂのプロットは、トーリックについて上記で示したような角度の関数として接線およびサジタル度数を示す。中間角度における接線誤差がドーナツトーリック未満であり、バレルトーリックよりも大きいことに留意されたい。サジタル度数は０および９０ではｒ＝０の場合について正しいが、半径の増加とともに多少とも対称的に両方の子午線上で欠け始める。軸対称ではない面の場合、接線曲率に対する角度態様からの弱い寄与がある。これは、通常のベクトルが円形断面と同じ面にないからである。
【００７１】
「偏りのない」ｃｙｌ補正を作り出す別の方法は、従来のドーナツトーリックおよびバレルトーリックの平均をとることである。こうすることにより、円形子午線から構築された面の場合の結果と類似した結果が得られる。平均をとったトーリックに関する角度プロットが図１４Ａ、Ｂに示され、そこではＺ＝ａＢＺＢ＋（１−ａＢ）ＺＤであり、ここでＺはレンズの面高さであり、ＺＢは従来のバレルトーリックの面高さであり、ＺＤは従来のドーナツトーリックの面高さであり、ａＢは１＞ａＢ＞０となるような重み係数である。図１４Ａ、Ｂは、ａＢ＝０．５の特定の場合を示すものである。
【００７２】
図１４のプロットから断言するのは難しいが、これらの円形子午線および平均をとったトーリック面に関する接線およびサジタル度数の角度挙動には大きな差異がある。図１５の輪郭プロットは、平均をとったトーリックおよび円形子午線関数の面非点収差を比較するものである。プロットは、上述の例と同じ０．１ジオプタの輪郭と４５ｍｍの直径とを有する。
【００７３】
非点収差は、平均トーリックの場合よりも円形子午線面の場合の方が単純な挙動をする。角度補間へのフーリエ項追加の効果を示すため、１つの余分な係数を、楕円形に見える輪郭を「切り上げる」ように調節することができる。その結果を図１６に示す。子午線は依然としてすべて円形断面を有し、角度補間のみがわずかに変更されていることに注目されたい。
【００７４】
円形子午線および平均トーリック面は注目すべきさらなる特性を有する。主子午線からずれた任意の点にある面の面非点収差は、同じ点におけるバレルトーリックまたはドーナツトーリックの面非点収差のうち大きい方よりも少ない。さらに、平均トーリックまたは円形子午線面は、同じ処方のバレルトーリックとドーナツトーリックとの間に位置する（中間Ｚ値を有する）。
【００７５】
上述のトーリックは、本発明の好ましい実施例のレンズの裏面として使用するのに好ましいが、レンズに提供するために従来のトーリックまたは一般化トーリックを使用することができる。
【００７６】
これに代えて、本発明のレンズ要素の面補正は、対称多項式の下記の数式に従って裏面を製造することにより提供し得る。
【００７７】
【数３】

【００７８】
レンズの光学収差の多くの測定値は下記のように定義される。
【００７９】
【数４】

ここでεは焦点誤差マトリクスであり、下記のように書ける。
【００８０】
【数５】

ここで、正規直交基の組を選択するとε１２＝ε２１である。
【００８１】
レンズの光学特性を特定的に考慮することによりこれらの項を計算する場合、光学平均度数誤差、光学ｃｙｌ誤差およびＲＭＳ光学度数誤差の項が適用される。
【００８２】
メリット関数は、最適化されたレンズの特定の用途に応じて下記の関数から選択され得る。
【００８３】
【数６】

ここで、合計は目の回転数θに対してとられる。
【００８４】
Ｍ４の場合には、サンプル点θが「まっすぐな」位置からの水平方向、垂直方向または斜め方向の回転を表すか否かにより種々のぶれ測定値が使用される。このモードは、非球面「最小接線誤差」設計戦略のある程度の一般化を提供し得る。
【００８５】
モードＭ３およびＭ５はそれぞれ、「最小非点収差誤差」および「最小平均度数誤差」戦略を表す。
【００８６】
さらなる実施例において、レンズの外見面を表すメリット関数にある項を含め得る。例えば、Ｍを単独で使用する代わりに、修正されたメリット関数が下記の式によって定義され得る。
【００８７】
【数７】

ここで、ηθはＭにおいて考慮されたサンプルの目の回転数θを示し、ｒは特定のレンズ半径であり、Ｖは半径ｒに向かうレンズ体積である。係数λは平均レンズ厚さに重みをつけるものであることがわかる。
【００８８】
ＩＩＩ．拡大および歪みの低減
眼鏡レンズはそれを通して見えた物体を縮小または拡大する。これは従来の眼鏡レンズの主面が水晶体に近接して置かれ、目の入射瞳と一致しないからである。一般に、プラス度数のレンズはものを大きく見せ、マイナス度数のレンズはものを小さく見せる。拡大は、周辺視界における物体の認識方向も変え、見かけの視界がレンズを通して見えた真の視界とは異なるようにする。
【００８９】
拡大に加えて、眼鏡レンズはさらに、それを通して見えた物体の形状を歪ませる。まっすぐ正面を見ている目の場合、マイナスレンズはいわゆる「バレル歪み」を引き起こし、この場合矩形の物体は周辺部で圧縮され、正方形はバレルのように見える。逆に、プラス度数のレンズは「ピンクッション歪みを引き起こし、正方形の隅を引き伸ばす。
【００９０】
これら２つの効果はともに、物体のサイズ、形状および位置の認識低下を増大する。眼科光学の教科書は、眼鏡レンズにおける歪みを補正するのは実用的ではないと教え、拡大効果を軽減することが望ましいということについては触れていない。それでも、コンタクトレンズの視野に関して喧伝される利点の１つは、レンズが目に密着することにより拡大および歪みの影響が軽減し、視野がより自然に補正できることである。眼鏡レンズの拡大および歪みの軽減は、可能であれば望ましいと思われる。
【００９１】
遠方の物体については、拡大効果は下記の式によって定義される。
【００９２】
【数８】

ここで、ｄ（図３のｄｖ）はレンズの裏面から目の入射瞳までの距離であり、Ｆｖはジオプタで表した裏面頂点度数であり、ｔはメートルで表した厚さであり、ｎは屈折率であり、Ｆ１はジオプタで表した表面度数である。
【００９３】
最初の括弧内にある式の部分は、どれだけの拡大がレンズ度数によるものかを示すため「度数係数」と呼ばれることが多い。ｄが０に等しければ、度数係数は１に等しいであろう。換言すると、目と接触しているレンズの場合にはこの度数による拡大が非常に少なく、これはコンタクトレンズの場合に言える。眼鏡レンズは目、瞼または睫との接触を回避するよう目から離れたところに位置づけられるため、この項はプラスレンズの場合には１より大きく、マイナスレンズの場合には１未満である。換言すると、プラス度数の眼鏡レンズは拡大し、マイナスレンズは縮小する傾向にある。状況に応じ、「拡大効果」という用語は拡大および縮小の両方を表すために用いられる。
【００９４】
第２の括弧内の式の部分は通常「形状係数」と呼ばれ、これはこの係数が、レンズの厚さおよび曲率とともに拡大率がどのように変化するかを示すからである。レンズに厚みがない場合、ｔは０に等しくこの項は１に等しいであろう。第３次光学の理想的な「薄いレンズ」では形状による拡大効果はない。コンタクトレンズは極端に薄く作れるので、この状況に近くなる。眼鏡レンズは損傷を回避するためにかなりの厚みを持たせてあり、常に正の表面曲率を有するため、この項は常に１より大きい。換言すると、すべての正のメニスカス眼鏡レンズはそれらの形状のために拡大する傾向にある。
【００９５】
拡大効果を排除するためには、式を１に等しく設定しなければならず、そのため度数係数と形状係数との積は１に等しい必要がある。プラスレンズの度数係数および形状係数はいずれも１より大きいため、それらの積は１にはなることはできず、正のメニスカス形態のプラスレンズから拡大効果を排除することはできない。一方、マイナスレンズの度数係数は１未満であり、形状係数は１より大きいため、これらの係数を打消すことは可能である。
【００９６】
これを行なうために、単位拡大についてこの式を解く必要がある。これを行なうと、下記の関係が得られる。
【００９７】
【数９】

この式は、眼鏡の拡大効果を排除するレンズ厚さを特定する。レンズの第２の主面を目の入射瞳に置くとうまくいく。実用的な厚さでこれを達成するには、２つのもの、すなわちマイナスレンズ度数と非常に急勾配の曲線とが必要である。
【００９８】
（歪み）
第３次理論によると、歪みは非実用的なまでに急勾配で湾曲したレンズにおいてしか除去できない。Ｊａｌｉｅ，Ｍ．「眼用レンズの原理」、４版４６２頁参照。
【００９９】
第３次理論では実際には、３５ジオプタを超える裏面曲線が必要であり、これは目の入射瞳付近でほぼ同心であり、そのような面は実際には非実用的である。目の入射瞳付近で両方の面が同心状になる真に同心のレンズ設計では、歪みは全くない。なぜならば、レンズの対称性により、斜めの物体からの光束のすべてが中央の物体からのものと同じ面傾斜に遭遇するからである。目の入射瞳付近での同心性には極端に急勾配の曲線は要求されないが、幾分平坦な曲線でも入射瞳に近接して置かれた主面を有するレンズと組合せた場合には歪みが飛躍的に低減されることを見出した。これはマイナス度数レンズにおける縮小を低減するように設計されたレンズによって行なわれ、この結果、目の回転中心まわりにほぼ同心状に配置されたレンズが得られる。
【０１００】
実際に、目の回転中心まわりでレンズを同心状に配置することは非常に望ましい。なぜならこれにより、周辺視界にある物体を見ようとして目が回転したときに目に対するレンズの対称性が改善され、その結果解像度が改善されるからである。レンズの一方の面が目の回転中心まわりで同心状に配置されることを厳密に要求するならば、歪みを事実上除去する厚さを導出できる。この場合、レンズ厚さに関する特定の形式の式が必要である。
【０１０１】
例えば、その表面が目の回転中心まわりで同心状に配置されたレンズの場合、表面の半径、着用距離、屈折率、裏面頂点度数、および目の回転中心からの入射瞳までの距離によってｔを求めることができる。この場合、
【０１０２】
【数１０】

ここで、
【０１０３】
【数１１】

はレンズの形状係数であり、ｒ１＝表面の半径であり、ｄｆ＝レンズ表面から入射瞳の面までの距離であり、Ｋｅは、図３に示されるように目の回転中心から目の入射瞳までの距離である。
【０１０４】
図１７Ａ〜図１７Ｃはこの種の設計の利点を示すものである。図１７Ａは、グリッドが見る人の左右に４５°延びるように、ある大きな距離から見えるより大きなグリッドを表す。図１７Ｂは、従来の−５．００Ｄレンズを着用した人が見る物の計算されたイメージであり、グリッドは小さく見え形状が歪んで見える。図１７Ｃは、上記式に従って歪みを排除するよう設計されたレンズの着用者に見える計算されたイメージを示す。このイメージは元の物体とほぼ同一に見える。
【０１０５】
ＩＶ．レンズ製造
本発明による眼用レンズ要素は、適切な任意の材料から作り得る。ポリマー材料が用い得る。ポリマー材料は任意の適切なタイプのものとし得る。ポリマー材料は、ポリカーボネートタイプなどの熱可塑性材料またはジアリルグリコールカーボネートなどの熱硬化性材料を含んでもよく、例えば、ＣＲ−３９（ＰＰＧインダストリーズ社）を用い得る。
【０１０６】
ポリマー品は、例えばその開示全体が引用により本明細書に組み込まれる米国特許第４，９１２，１５５号または米国特許出願番号第０７／７８１，３９２号に記載されるように、架橋性ポリマー成型組成物から形成し得る。
【０１０７】
ポリマー材料は、例えば、フォトクロミック色素を含む色素を含むことができ、これはポリマー材料製造に使用されるモノマー処方に添加できる。
【０１０８】
本発明による光学レンズ要素は、エレクトロクロミックおよび／または液晶コーティングを含む付加的な標準コーティングを表面または裏面にさらに含み得る。レンズ表面は反射防止（ＡＲ）コーティングを含んでもよく、これは例えば開示全体が引用により本明細書に組み込まれる米国特許第５，７０４，６９２号に記載のタイプのものとし得る。サングラスのレンズを作ったり、または所望の見かけ上の効果を提供するため、部分的反射コーティングをレンズに適用し得る。レンズの表面は、これに代えて、またはこれに加えて、開示全体が引用により本明細書に組み込まれる米国特許第４，９５４，５９１号に記載のタイプの耐磨耗性コーティングを含み得る。
【０１０９】
表面および裏面は、反応抑制剤、例えば上述のサーモクロミックおよびフォトクロミック色素を含む色素、偏光剤、ＵＶ安定剤および屈折率を変更し得る材料などの成型組成物に従来から用いられている１つ以上の面処理を含み得る。
【０１１０】
図１８は、本発明の教示によるレンズ要素の製造に適する金型を示す。金型は表金型部分３００と、裏金型部分３０２と、閉フランジ部分３０４とを含む。レンズ要素は、ポート３０８を通して液状のレンズ材料を注入することにより、金型間のキャビティ３０６中で形成し得る。空気はポート３１０を通って逃げる。レンズ要素が硬化すると、金型部分が分離される。レンズ要素は金型から取り出されるときに放射状フランジ３１２を有しているのが観察されるであろうが、これは後の処理において除去される。
【０１１１】
本発明のレンズ要素を成型するための方法および装置は、２０００年９月８日提出の、「熱可塑性レンズの成型方法、およびそれにより製造された急勾配で湾曲したおよび／または薄いレンズ」と題されたＫｉｎｇｓｂｕｒｙらの米国特許出願番号第０９／６５８，４９６号に記載されており、その内容は引用により本明細書にその全体が組み込まれる。
【０１１２】
Ｖ．レンズ設計例の計算された性能
（例１）
表１は、本発明に従って作られたポリカーボネートレンズと従来の低ベースカーブレンズとの、計算された性能の比較を示す。
【０１１３】
【表１】

【０１１４】
（例２）
図１９は、−６Ｄ、−３Ｄおよび＋３Ｄ度数の急勾配で湾曲した一連の球状レンズ要素（それぞれ図１９（ａ）、図１９（ｃ）および図１９（ｅ））と対応する低ベースカーブＳｏｌａ　Ｐｅｒｍａ−Ｐｏｌｙ（登録商標）素材レンズ（それぞれ図１９（ｂ）、図１９（ｄ）および図１９（ｆ））との計算された比較を示す。
【０１１５】
急勾配で湾曲した球状レンズ要素は、レンズ断面４００に示されるように、本質的に同一な１６Ｄの球状表面を有する。一般に、急勾配で湾曲した球状レンズ要素により周辺歪みが改善される。図１９（ａ）および図１９（ｃ）のレンズも、マイナス処方において低いＲＭＳ度数誤差を示す。
【０１１６】
（例３）
図２０は、１６Ｄ表面−３Ｄ透視度数および−２の裏面ｃｙｌ補正が付与された急勾配で湾曲した２つの球状レンズの計算された比較を示す。
【０１１７】
図２０（ａ）のレンズは従来のドーナツトーラス裏面を有し、図２０（ｂ）のレンズは上記のタイプの全円形子午線裏面を有する。後者は、ＲＭＳ度数誤差が優れており、歪みがいくらか改善されている。
【０１１８】
（例４）
最後の例の組（図２１および図２２）は、従来のベースカーブ累進レンズと本発明による累進レンズとの比較を示す。
【０１１９】
図２１は、従来の湾曲Ｓｏｌａ　ＸＬ累進レンズの遠視野特性と、急勾配で湾曲した（１６Ｄ）ベースカーブを有するレンズ要素に類似した累進形式が置かれたレンズとを比較する。
【０１２０】
図２２は、Ｓｏｌａ　ＸＬ累進レンズと図２１の急勾配で湾曲したレンズとの近視野特性を比較する。
【０１２１】
一般的に言えば、本発明に従って作られた累進レンズは、着用位置で着用者の目の回転中心とほぼ同心の急勾配で湾曲した基準球体または球状シェルによって特徴づけられる。そのようなレンズは、遠視野用の上方観察ゾーンと、上観察ゾーンよりも高い度数を有する近視野用下方観察ゾーンと、上方ゾーンと下方ゾーンとをつなぐ中間ゾーンとを有し、上ゾーンと下ゾーンとの間で度数は変化し、比較的低い面非点収差のコリドーを含む。
【０１２２】
１つの実施例において、急勾配で湾曲した基準球体は、上方観察ゾーンの中央部分の表面に対応する。別の実施例において、累進面はレンズの表面にあり、約２ｍｍ未満の厚さの、急勾配で湾曲した球状シェル内に位置する。いずれの実施例においても、シェルまたは基準球体の曲率半径は５０ｍｍ未満とすることができ、好ましくは約３０ｍｍ〜３５ｍｍ、最も好ましくは約３３ｍｍ±約２ｍｍとし得る。累進レンズの適切な表面設計は、例えば、１９９７年７月１０日提出の本願出願人の、現在は米国特許第５，８６１，９３５となっている特許出願番号第０８／７８２，４９３号に示される。
【０１２３】
ＶＩ．嵌められたレンズおよび眼鏡フレーム
本発明で使用される眼鏡フレームは、図３に示されるおよその位置において本発明のレンズを保持するように適合される。眼鏡フレームは、リムレス、部分リム、またはフルリムとし得る。
【０１２４】
好ましい実施例において、レンズは、眼鏡フレームに取付けた場合に、本質的に傾斜したりラップ角を示したりしない。眼鏡フレームは、レンズの光軸の位置を、着用者のまっすぐな視野の軸に対応するよう変更するための、調節可能な機構を含み得る。
【０１２５】
図２３は、本発明のレンズ４０２および４０４ならびに眼鏡フレームを含むアイウェア４００を示す斜視図である。レンズ形状により見かけ上好ましい物が得られる。図２３の眼鏡フレームは、リム部分４０６と側頭部品４０８および４１０と共に示してある。各レンズを囲む眼鏡フレームのリムは、レンズの急勾配で湾曲した基準球体上またはその付近に位置する閉曲線に対応するように適合される。処方範囲にわたりこの曲率が一貫していることにより、単一フレームまたはフレーム設計がこの範囲での任意の処方に対して適合され得る。
【０１２６】
図２４は、着用者の顔に着用された場合の、図２３のアイウェアの側面図である。この図は、レンズの急勾配で傾斜した曲率およびレンズエッジの複雑な３次元形状により得られる着用者の外見に関する別の局面を示す。この図は、比較的小さいサイズのレンズにより広い視野および目に対する優れた保護が提供されることを示す。
【０１２７】
図２５Ａ、Ｂは、本発明によるアイウェアの実施例４１２を前方から見た図であり、本発明のいくつかの機械的局面を示す。図２５の実施例の眼鏡フレームはノーズブリッジ４１４ならびに蝶番式側頭部品４１６および４１８を含む。これらの構成要素を併せると、３部材のリムレス眼鏡フレームが構成される。
【０１２８】
側頭部品４１６と４１８は、蝶番４２０および４２２と、取付タブ４２４および４２６とを含む。好ましい実施例において、タブ４２４および４２６は、レンズの球状表面に取付けられる。これらの取付面は、処方された透視度数およびレンズのｃｙｌ補正に関係なく、フレームに対して一貫した位置および角度関係で置かれることが理解されるであろう。同様に、ノーズブリッジ４１４のタブ４２８および４３０は、レンズのそれぞれの表面エッジに表面取付けできる。
【０１２９】
ノーズブリッジ４１４は、図２５Ｂにおいて断面図で示される。有利には、ノーズブリッジは種々の着用者に通常見られる種々の瞳孔距離（図３のＰＤ）を補償するための調節可能長さに作られる。この調節可能な特徴により、レンズの光軸が着用者の両目の視野軸と整列できるようになる。この調節可能な特徴を生み出すのに適切な１つの機械的構造が図２５Ｂに示されるが、移動または柔軟構造の他の組み合わせをこの目的に適合できることが理解される。図２５Ｂの実施例では、タブ４２８および４３０の各々が、それぞれ部材４３２および４３４によって保持され、これらは管４３６の両端に挿入される。固定ネジ４３８および４４０は、部材４３２および４３４を定位置に保持する。固定ネジは、管の中で部材４３２および４３４を種々の位置まで摺動させることによりノーズブリッジ長さを調節可能にするよう緩めることができる。
【０１３０】
図２６（ａ）は、本発明のアイウェア実施例５００の平面図である。アイウェアはリムレスタイプである。左のレンズ５０２および右のレンズ５０４は、急勾配で湾曲し、エッジ加工されたレンズである。好ましい実施例においては、これらのレンズは、上記のように曲率半径が５０ｍｍ未満、好ましくは３５ｍｍ未満の、一般に球状である前方光学面５０６をそれぞれ有している。着用時位置においては、各レンズの球状面の曲率半径中心は、着用者のそれぞれの目の回転中心ＰＬ、ＰＲにほぼ位置する。
【０１３１】
レンズ５０２および５０４は、レンズを着用者の顔面上で支持するために、ノーズブリッジ５０８により連結される。左右の側頭部品５１０および５１２が設けられ、左右のレンズの側頭エッジにそれぞれ取り付けられる。好ましい取り付け方法を、図２６（ｂ）に関連して論じる。
【０１３２】
図２６（ｂ）は、右の取り付け部品５１４およびヒンジ５１６による右の側頭部品５１２の右レンズ５０４への取り付けを示す図２６（ａ）の実施例の細部である。好ましい実施例において、右の取り付け部品はアーチ形であり、一般にレンズ５０４の前方面の球面曲率に沿って続く。取り付け部品５１４のノーズ部分５１８はレンズの表面上に置かれる。ボルト５２０およびナット５２２のような螺合固定システムは、取り付け部品をレンズの定位置に保持するために使用できる。好ましい実施例において、取り付け部品の突出部５２６を受け入れて取り付け部品をより固定し、さらにボルト５２０の主軸５２８まわりでのその回転を妨げるために、レンズにエッジノッチ５２４を設けることができる。好ましい実施例において、ファスナーの主軸５２８は、レンズの球状面の曲率中心を横切る放射状線上に位置する。
【０１３３】
本発明のレンズ要素の好ましいエッジ加工も、図２６（ｂ）において詳細に示される。示されているように、レンズのエッジ面５３０は、レンズの球状面の半径方向５３２にほぼ沿って位置する。着用時位置では、この半径方向は、目の回転中心、ＰＲにほぼ中心づけられる。このエッジ形態により、着用者にはレンズエッジが本質的に見えなくなる。なぜならば、目が回転する時に、エッジ面が着用者によりエッジオンに見られ、その結果、凝視角度はレンズエッジに向けられるからである。さらに、エッジ面はサイズが小さくされ、外部の観察者への外見が最小限になる。このエッジ加工の詳細は図２７および図２８に例示する。
【０１３４】
図２７Ａ〜図２７Ｄは、レンズの球状面５３４の半径方向、Ｒにほぼ沿って位置するいくつかの種々のエッジ輪郭を例示する。これらの図に例示されるように、エッジ面の断面は、球状面の接線Ｔにその外周部においてほぼ垂直、すなわち、視線は、エッジ面とほぼ共面である。
【０１３５】
図２７Ａ〜図２７Ｄにおいては、各エッジ面の断面は、目の回転中心Ｐについて小さい角度範囲θ内に位置し、従って着用者にはほとんど見えない。図２７Ａの例においては、エッジ面の断面は直線５３６であり、θは０に接近する。図２７Ｂの例においては、さもなければ安全上の問題をもたらすことがある鋭いエッジを取り除くために若干の丸みつけが実施されている。図２７Ｃの例においては、溝５３８がエッジに切ってあり、これはアイウェアのリムに対応して形成された部分５４０と嵌まり合うように適合されている。最後に、図２７Ｄの例においては、エッジ面にビード５４２が形成されており、これはアイウェアフレームの溝付きリム５４４と嵌まり合うに適合されている。これらの後のケースでは、エッジ面は着用者にとりほとんど見えない。
【０１３６】
図２７Ｂ、図２７Ｃおよび図２７Ｄの例においては、有利には、レンズ全周まわりでθは約５°未満である。この状況は図２８に例示されており、これは本発明の好ましい実施例に従って作られたエッジ加工したレンズ５４６の絵画図である。レンズのエッジ面５４８は、レンズの球状面５５０の接線に垂直な環である。この環は、それが１つの平面中に完全にあるわけではないという意味で三次元である。エッジ面は、２つの一般に円錐形５５２および５５４の間にあり、角度θを張っており、この角度は、レンズ周辺の種々の位置で多少変わり得るが、典型的には３°±１．５°未満である。
【０１３７】
図２９Ａ〜図２９Ｃは、いくつかのレンズエッジ加工法を例示するものである。図２９Ａは、従来のオストワルトセクションレンズ５６０のエッジ加工を示すもので、軸５６４まわりで回転される従来のミル５６２を用い、この軸は参照軸５６６と平行に保持される（この軸はレンズブランクの光軸とすることができる）。ミルの軸５６４は、矢印５６８により示されるようにレンズ周辺を動かされてエッジ面を形成する。急勾配で湾曲したレンズ５７０をエッジ加工するための同様な手法の使用は図２９Ｂに示してある。その結果、エッジ加工されたレンズは、鋭いエッジ５７２および着用者の周辺視野における大きい角度を張るエッジ面を持つ。
【０１３８】
本発明の好ましい実施例に従って、図２９Ｃに例示されるように、急勾配で湾曲したレンズ５７０のエッジ面５７４は、レンズの球状面の曲率中心Ｃを横切っている軸５７６まわりで回転されるミル５６２によって生成できる。以前は、そのような配置は、非急勾配で湾曲したレンズをエッジ加工するためにのみ使用されてきた。
【０１３９】
ＶＩＩ．コーティング、サンレンズおよび保護アイウェア
Ａ．コーティング
本発明のもののような高い曲率の面を有しているレンズ要素は、反射率／透過率を制御するためにフィルムでコーティングするのがとりわけ困難なことがある。これらの難題は、少なくとも部分的に、典型的なコーティング、蒸着およびスパッタリングシステムのジオメトリにより引き起こされる。これらのシステムは、比較的平坦なレンズ要素の中心からエッジへ比較的均一なフィルムを形成することができる。しかしながら、面曲率が急勾配になるにつれてより大きい変動が観察される。レンズ要素の知覚される色は、フィルム厚さと共に変化する。この色は、視角の変化によってもレンズ全体にわたって変わることがある。この効果は、急勾配で湾曲したレンズにおいてより大きい。これらの問題は、「ロールオフ」と呼ばれることがある。
【０１４０】
レンズ要素、特に大きく湾曲したレンズ要素をコーティングするための技術は、「実質的に均衡のとれた反射率を示すコーティングされたレンズ」と題された上記の国際出願番号第ＰＣＴ／ＡＵ９９／０１０２９号に開示されている。複数の酸化被膜層の「スタック」により構成されるコーティングの様々なタイプも論じられている。そのようなスタックは、図３０Ａに一般的に例示される。この例では、急勾配で湾曲したレンズ６００は、球状前面６０２が多層フィルム６０４で被覆されている（一定比率では描かれていない）。
【０１４１】
コーティングされた急勾配で湾曲したレンズ要素の中心からエッジにかけて一般に均一な淡青色の外観を提供する反射防止コーティングの例は、種々の厚さの酸化ケイ素および酸化ジルコニウムの５つの層のスタックで構成される。スタックは、下記の表Ｉに示してある。
【０１４２】
【表２】

ロールオフの低減だけでなく、レンズは、レンズ表面の指紋が目立ちにくくなり、他の系統的および非系統的な製造のばらつきに影響されにくくなる。これらの利点は、従来のオストワルトセクションレンズにおいても達成できる。
【０１４３】
前述の酸化物コーティングのスパッタリング堆積技術は、２０００年６月２８日提出のＢｕｒｔｏｎらの米国特許出願番号第０９／６０５，４０１号に開示されており、その内容は参照によりその全体が本明細書に組み込まれる。
【０１４４】
図３１および図３２は、本発明のコーティングの様々な局面を例示する。図３１は、ナノメートルで表した光波長の関数としてパーセントで表した反射のプロットである。この図は、表Ｉのスタックの反射率を、緑がかった色を有する従来のスタック（破線）と比較するものである。
【０１４５】
堆積されたフィルム厚さが３％以上変動すると、通常有意かつ顕著な色変化が引き起こされる。緑の呈色は、反射スペクトル（図３１）中の「ハンプ」６５０の効果であり、斜めの角度で見た時に、スペクトルの青色端部へ移動するように見える。これが起こる場合には、スペクトルの赤色端部での反射率がより強くなる。これは結局、（所望の黄色／緑色ではなくて）ピンクまたは紫色という結果になる。
【０１４６】
対称的に、表Ｉ（青色）のスタックは、スペクトル中の約４８０ｎｍにおけるピークまたはハンプ６５２で表されるような青色部分における支配的量の可視光反射率を示す反射率スペクトルを生み出す。青色コーティングは、スペクトルの赤外領域中まで非常に低い反射率を示し、７２０ｎｍで０．５％未満、好ましくは０．２５％である。
【０１４７】
急勾配のレンズ曲率の効果は図３２に例示される。理解されるように、各レンズの中心におけるスペクトルの赤色端の反射率は、青色コーティングの場合よりも緑色コーティングの場合のほうが高い。しかしながら、反射がレンズのエッジに向かって測定される場合には、緑色コーティングが、スペクトルの赤部分で反射率が大きく増大するのに対して、青色コーティングは低い赤反射率で安定していることが明瞭に見られる。
【０１４８】
レンズのエッジへ向かっての、この赤反射の増大の結果は、「緑色」コーティングが明るい紫色に変わる（緑＋赤＝紫）ことである。この効果は、青色コーティングの場合にはどのような有意な程度でも生じない。色ロールオフに対するこの感度減少の最終結果は、ＡＲ堆積時に色の一致を維持するために標準レンズ曲率グルーピングの必要が大きく減少することである。急勾配で湾曲したレンズ表面が、面全体にわたって、あるいはその面の大いに増大した部分（緑色コーティングのようなより普通のコーティングと比較して）にわたってそれらの色を保持することが明白であろう。
【０１４９】
Ｂ．サンレンズ
可視およびＵＶ域の光の波長を選択的にブロックするサンレンズまたはサングラスを提供することは常套的である。そのようなレンズは、目保護およびファッションデザインの両方の用途を有している。レンズを通る光の波長は、プラスチック製ボディ中の光吸収性色素を使用することにより選択し得る。これに代えて、あるいは加えて、レンズに鏡面反射コーティングを適用し得る。これらの技術は、本発明の急勾配で湾曲したレンズに適用できる。さらに、これらの技術は、上述の反射防止コーティングと共に用い得る。例えば、上記のＡＲコーティングは、日光を部分的にブロックする色素を含んでいるレンズの目側の光学面に適用できるであろう。これに代えて、前方光学面が例えば鮮やかな青い反射性コーティングで鏡面コーティングされる一方で、上記のＡＲコーティングをレンズの目側の光学面に適用できるであろう。
【０１５０】
Ｃ．レーザー保護アイウェア
上記の急勾配で湾曲した球状面レンズ要素は、レーザー保護アイウェアにおいて有利に用い得る。好ましい実施例において、アイウェアは、各レンズの曲率中心を、アイウェアが使われるそれぞれの目の回転中心に置くように設計される。さらに、レンズは、レンズがほぼ眼窩の鼻マージンから側頭マージンへ、および眼窩の下マージンから上マージンへ延びるようにエッジ加工し得る。これに代えて、レンズは、前記眼窩マージンへ延びるアイウェアフレームに取り付け得る。これらの形態にはいくつかの有益な効果がある。第１に、レンズは目を効果的に取り囲み、エッジまわりの迷光漏れを低減または防止できる。第２に、本質的に瞳孔を通って伝達され得るレンズに入射するすべての光は、球状面の接線への垂線に関して約２５°〜３０°以内になる。入射角がより大きい光は、瞳孔を通って導かれない。レンズ上または内部のレーザー光ブロック手段は、球状面の接線への垂線のこのほぼ３０°の角度範囲内のレーザー光のビームをブロックするように調整し得る。
【０１５１】
バンドブロッキング光学フィルタは、ブロックすべき光の入射角度に敏感になり得ることは知られている。一般的に、そのようなフィルタは設計中心として垂直入射光を使う。フィルタの有効性は、一般的に変化し、通常は垂線からの入射角の逸脱と共に減少する。このジオメトリは、図３０Ａにおいて、それぞれ入射角φ１およびφ２を有している２つの任意の光線Ｒ１およびＲ２について例示してある。角度φ１およびφ２は、光線Ｒ１およびＲ２がレンズの面と交差する点における垂線Ｎ１およびＮ２に関して測定される。（垂線は、接平面Ｔ１およびＴ２に対して、それらのそれぞれの交点において垂直である）。一般に、上で論じたフィルタの場合、φが大きければ大きいほど、フィルタ効果は効果的がなくなるであろう。
【０１５２】
本発明の急勾配で湾曲したレンズは、典型的には関連入射角度φのより小さい範囲を呈し、これにより、例えば、垂線から約３０°までの効果的な除去角度を有するフィルタの使用が可能になる。急勾配で湾曲したレンズのこの局面は、図３０Ｂおよび図３０Ｃに示される２つのレンズ例の比較において例示される。図３０Ｂに示されるレンズ６１０は、オストワルトセクション、−４Ｄベースレンズである。図３０Ｃに示されるレンズ６１２は、−４Ｄ透視度数および約１５．５Ｄの球状表面を有する急勾配で湾曲したレンズである。入射光線の分析は、両方のレンズが１．５の屈折率および約２ｍｍの中心厚さを有していると仮定している。１ｃｍ直径瞳孔Ｐが、レンズ裏面がその光軸Ｏ−Ｏと交差している点の２ｃｍ後ろに位置していることも想定されている。
【０１５３】
種々の入射光線が図３０Ｂおよび図３０Ｃにプロットされている。光線は、光軸Ｏ−Ｏにおいて各レンズに接する平面ＰＴと交差する光束から選ばれる。束は、光軸Ｏ−Ｏの上下に０、５、１０、１５および２０ｍｍの距離で試験される。各束から、（ｉ）レンズ面上の入射点におけるレンズへの垂線に関して最大の角φを有し、および（ｉｉ）レンズにより屈折された場合に瞳孔の最下点Ｌに到達する、光線が選ばれる。これらの選ばれた光線は、平面ＰＴ上の光軸の上下のそれらの個々の距離（例えば、５ｍｍ、１０ｍｍ等）により識別される。
【０１５４】
以下の表は、図３０Ｂおよび図３０Ｃのレンズについての入射光線の各々についての計算された角度を示す。
【０１５５】
【表３】

（角度φは、正および負の両方の角度として表わされる。正の角度は、図に示されるようにレンズ垂線から時計回りのビーム回転を示し、負の角度は、レンズ垂線から反時計回りのビーム回転を示す。）
この例では、オストワルトセクションレンズについてのφは、多くの位置において３０°より大きく、かつ光軸からの距離に伴って、＋２０ｍｍ位置における５３．７の高さまで劇的に増大する。対称的に、図３０Ｃの急勾配で湾曲したレンズについては、角度φは３０°未満に留まる。
【０１５６】
レーザー光の選択的ブロッキングは、１つ以上の光学バンドブロックフィルタで達成できる。レーザー光の選択的ブロッキングを作り出す好ましい方法は、潜在的に有害なレーザー光をブロックするように調整された薄膜スタックを用いることである。以下は、遠距離通信において頻繁に使われる２つのレーザー光波長、すなわち１３１０ｎｍおよび１５５０ｎｍレーザー光を効果的にブロックするバンドフィルタの例である。光学フィルタは、表ＩＩＩにおいて層構成および厚さについて記載される。
【０１５７】
【表４】

光学設計の語法において、このスタックは以下の表現により記述される：
「１．１２（０．５Ｌ　Ｈ　０．５Ｌ）１．０６（０．５Ｌ　Ｈ　０．５Ｌ）１．０３（０．５Ｌ　Ｈ　０．５Ｌ）（ＬＨＬ）∧６
１．０３（０．５Ｌ　Ｈ　０．５Ｌ）１．０６（０．５Ｌ　Ｈ　０．５Ｌ）１．１２（０．５Ｌ　Ｈ　０．５Ｌ）」
ここで、ＨおよびＬは、それぞれ高屈折性および低屈折率材料の目標波長における１／４波長光学的厚さを示す。表ＩＩＩの例では、低屈折率材料は二酸化ケイ素であり、高屈折率材料は二酸化チタンである。レーザー光からの保護のためのバンドブロックフィルタを提供するために、従来設計の種々の他のスタックが使用できることが理解されるであろう。
【０１５８】
表ＩＩＩの例を続けると、光学濃度（透過百分率の対数の負号）は、図３３に入射光波長の関数としてプロットしてある。この図からわかるように、ブロックされたバンドは、約１４００ｎｍに中心がある広いバンドである。大部分の可視波長は通過される（すなわち、光学濃度は０に近い）。
【０１５９】
図３３のプロットは、入射点におけるレンズ面の接線Ｔに垂直な線Ｎについて０度の入射角φを想定している（図３０Ａ参照）。スタックの光学濃度は、入射角φが０から増加するにつれて変化することが予期される。ＳおよびＰ偏光ならびに１３１０ｎｍおよび１５５０ｎｍ波長の入射光について予期されるずれは、図３４においてプロットされている。
【０１６０】
より具体的には、図３４において、光学濃度は０〜６０°の入射角の関数としてプロットされる。光入射が増加するにつれて、全体のブロックバンドが左へ（青に向かって）シフトすることが理解されるであろう。このため、光学濃度は、１３１０ｎｍ波長の場合に増大する。入射角φが増大するにつれて、１５５０ラインの光学濃度が減少する。表ＩＩＩのスタックについては、３０度未満の角度において、光の約０．７％未満が伝達され、偏光を問わず、２０度未満では光のわずか約０．２％が伝達される。これは、商用安全アプリケーションには十分であると信じられる。もっとも、軍用要件はより厳格であり、さらに特定のバンドにおいてより大きい光学濃度を有するスタックデザインが要求されることがある、
両方の波長および約３３°までの入射角における偏光について、スタックの透過率が１％未満に留まることが図３４から認められるであろう。これよりも大きい入射角は、保護されている目の回転中心付近にその曲率中心が位置する本明細書に記載の急勾配で湾曲したレンズ中において網膜に向けられることがないであろう。しかしながら、強い反射、屈折または光漏れにより引き起こされる好ましくない透過に対して保険をかけるため、レンズボディは、放射吸収色素を含む熱可塑性物質から成型することもできる。
【０１６１】
従って、急勾配の球状曲率を持つ新規で高い光学品質のレンズ要素が処方透過度数およびｃｙｌ補正と共に提供され、さらにそれを使用するように適合させた眼鏡フレームに取り付けられる。これらの設計は、非常に効果的なサングラスおよびレーザー保護アイウェアのような他の保護アイウェアでの使用に容易に適合される。
【０１６２】
本発明をさまざまな実施例および例に関連して説明してきた。しかしながら、保護されるべき本発明は、前記の特許請求の範囲および法律において認識されるその等価物によって定義される。
【図面の簡単な説明】
【図１】
チェルニング楕円の図である。
【図２】
先行技術の高プラス度数「ロトイド」レンズの断面図である。
【図３】
人の１対の目と、本発明の好ましい実施例に従って構成されたレンズとを示す上方から見た断面図である。
【図４】
本発明の教示に従って作られた一連のレンズ要素の特性を示すモリス−スプラット図である。
【図５】
本発明に従って選択された前曲線および透視度数範囲の図であり、この特殊な場合に関するチェルニング楕円の一部分が重ねて描かれている図である。
【図６Ａ】
本発明の実施例のレンズ要素のジオメトリの種々の局面を示す概略図である。
【図６Ｂ】
本発明の実施例のレンズ要素のジオメトリの種々の局面を示す概略図である。
【図６Ｃ】
本発明の実施例のレンズ要素のジオメトリの種々の局面を示す概略図である。
【図７】
本発明の実施例のレンズ要素のジオメトリの種々の局面を示す概略図である。
【図８】
本発明の実施例のレンズ要素のジオメトリの種々の局面を示す概略図である。
【図９】
本発明の実施例のレンズ要素のジオメトリの種々の局面を示す概略図である。
【図１０】
６ベース従来レンズならびに本発明のレンズおよびレンズ要素の例について視界を比較する図である。
【図１１Ａ】
図１１Ｃに示される主子午線を有する急勾配で湾曲した球状レンズに付与された場合の、従来のドーナツトーリックの面非点収差を示す図である。
【図１１Ｂ】
図１１Ｃに示される主子午線を有する急勾配で湾曲した球状レンズに付与された場合の、従来のバレルトーリックの面非点収差を示す図である。
【図１１Ｃ】
円形の主子午線曲率を示す図である。
【図１２Ａ】
図１１のドーナツトーリックの極角度の関数として、接線面度数を示すグラフである。
【図１２Ｂ】
図１１のドーナツトーリックの極角度の関数として、サジタル面度数を示すグラフである。
【図１２Ｃ】
図１１のバレルトーリックの極角度の関数として、接線面度数を示すグラフである。
【図１２Ｄ】
図１１のバレルトーリックの極角度の関数として、サジタル面度数を示すグラフである。
【図１３Ａ】
本発明の全円形子午線の極角度と平均トーリック面との関数として接線面度数を示すグラフである。
【図１３Ｂ】
本発明の全円形子午線の極角度と平均トーリック面との関数としてサジタル面度数を示すグラフである。
【図１４Ａ】
本発明の全円形子午線の極角度と平均トーリック面との関数として接線面度数を示すグラフである。
【図１４Ｂ】
本発明の全円形子午線の極角度と平均トーリック面との関数としてサジタル面度数を示すグラフである。
【図１５】
本発明の教示を用いるレンズ要素面の面非点収差を示す輪郭プロット図である。
【図１６】
本発明の教示を用いるレンズ要素面の面非点収差を示す輪郭プロット図である。
【図１７Ａ】
物体グリッドおよびその像を示す図である。
【図１７Ｂ】
物体グリッドおよびその像を示す図である。
【図１７Ｃ】
物体グリッドおよびその像を示す図である。
【図１８】
本発明の実施例のレンズ要素を製造するために用いられる金型を示す、側方断面図である。
【図１９】
３つの従来の低ベースレンズと、本発明による急勾配で湾曲した３つのレンズ要素とについて計算された、ＲＭＳ度数誤差および歪みならびに光線追跡グリッドを示すプロット図である。
【図２０】
従来のトーリック裏面を有する急勾配で湾曲したレンズおよび全円形子午線裏面について計算されたＲＭＳ度数誤差、歪みおよび光線追跡グリッドを示すプロット図である。
【図２１】
従来の６Ｄベース累進レンズと、本発明による１６Ｄベース累進レンズとを比較する輪郭プロット図である。
【図２２】
従来の６Ｄベース累進レンズと、本発明による１６Ｄベース累進レンズとを比較する輪郭プロット図である。
【図２３】
本発明のレンズ要素およびそれと共に使用する眼鏡フレームの外見、エッジ加工およびガラス嵌めに関するさまざまな局面を示す図である。
【図２４】
本発明のレンズ要素およびそれと共に使用する眼鏡フレームの外見、エッジ加工およびガラス嵌めに関するさまざまな局面を示す図である。
【図２５Ａ】
本発明のレンズ要素およびそれと共に使用する眼鏡フレームの外見、エッジ加工およびガラス嵌めに関するさまざまな局面を示す図である。
【図２５Ｂ】
本発明のレンズ要素およびそれと共に使用する眼鏡フレームの外見、エッジ加工およびガラス嵌めに関するさまざまな局面を示す図である。
【図２６】
（ａ）は本発明のアイウェアの実施例の平面図であり、（ｂ）は取り付け部品、ヒンジ、およびエッジ加工したレンズ構造を示す図２６（ａ）の実施例の詳細図である。
【図２７Ａ】
本発明の好ましい実施例において用いられる種々のレンズエッジ面の例示図である。
【図２７Ｂ】
本発明の好ましい実施例において用いられる種々のレンズエッジ面の例示図である。
【図２７Ｃ】
本発明の好ましい実施例において用いられる種々のレンズエッジ面の例示図である。
【図２７Ｄ】
本発明の好ましい実施例において用いられる種々のレンズエッジ面の例示図である。
【図２８】
エッジの厚さを例示する、本発明のエッジ加工したレンズの絵画図である。
【図２９Ａ】
いくつかのレンズエッジ加工法の例示図である。
【図２９Ｂ】
いくつかのレンズエッジ加工法の例示図である。
【図２９Ｃ】
いくつかのレンズエッジ加工法の例示図である。
【図３０Ａ】
種々のレンズ要素の断面図であり、レンズの表面に当たる入射光線と共に示した図である。
【図３０Ｂ】
種々のレンズ要素の断面図であり、レンズの表面に当たる入射光線と共に示した図である。
【図３０Ｃ】
種々のレンズ要素の断面図であり、レンズの表面に当たる入射光線と共に示した図である。
【図３１】
本発明の局面を例示する、種々のコーティングについての、反射対入射光波長のプロット図である。
【図３２】
本発明の局面を例示する、種々のコーティングについての、反射対入射光波長のプロット図である。
【図３３】
本発明の好ましい実施例のバンドブロックフィルタの例についての光学濃度のプロット図である。
【図３４】
本発明の好ましい実施例のバンドブロックフィルタの例についての光学濃度のプロット図である。[0001]
(Technical field)
The present invention relates to improved ophthalmic lens elements and eyewear, including prescription lenses, eyeglasses, sunglasses, laser protective eyewear, and frames, coatings and edgings therefor.
[0002]
(Background technology)
Most conventional prescription lenses have a relatively flat base curve. Such lenses have a limited field of view due to marginal distortion and / or physical size limitations. Due to their relatively flat shape, the amount of eye protection provided by the lens is limited, especially near the temporal.
[0003]
Wrap-around eyewear has been developed to provide a wider field of view and greater eye protection. The wrap-around design also allows for an overall style for eyewear that is diverse and sometimes impressive. However, wrap-around eyewear is typically non-prescription. These products also have a flat base curve, typically 6-10D. Wrap (and sometimes rake) is achieved by rotating and / or translating the lens optical axis in the direction in which it is worn. See, for example, Rayton U.S. Pat. No. 1,741,536 and Houston et al. U.S. Pat. No. 5,689,323. This often causes the line of sight of the wearer to deviate from the optical axis, greatly reducing optical performance. Peripheral vision is typically poor.
[0004]
Early in the history of ophthalmology, steeply curved prescription lenses were described, although not as a means to provide greater vision or eye protection. The relationship between curvature and perspective power is shown in a so-called "Cherning" ellipse. It was first described about 100 years ago and seeks to identify a combination of lens curvature and lens power with the least aberration. The general shape of the Chernning ellipse is shown in FIG. FIG. 1 is given for typical values of assumptions about lens parameters such as refractive index, vertex distance, lens thickness, and the like. The Chernning ellipse retains its elliptical shape and tilted orientation for various hypothetical values of the lens parameters, whereas the exact position on the ellipse can vary. The ellipse in FIG. 1 is derived from a corrected von Rohr equation (named Morgan) solved for a circular focus (zero astigmatism) far field.
[0005]
The lower part 10 of the ellipse is the so-called "Ostwald section", which describes the choice of a relatively flat surface for the lens power typically used in conventional prescription ophthalmic lenses. The top 12 of the curve is called the "Wollaston section" and represents a much steeper, curved lens, although there are historical examples of attempts to make such (eg, Wollaston himself). ), Has never been accepted as a lens form. M. Jalie, Principles of Ophthalmic Lenses, p. 464 (4th edition, London, 1994). Due to difficulties in fabrication, such early lenses would have been considered unacceptable, probably with small apertures, possibly due to apparent reasons and limited field of view.
[0006]
Recent lenses with steeply curved spherical surfaces have been created for the treatment of aphakicosis (a natural lens defect in the eye, such as when the lens is surgically removed). The general form of these lenses is shown in FIG. M. See Jalie, page 151. Such lenses act essentially as lens replacements and are characterized by a large thickness and a high positive power (greater than + 5D, typically + 12D or more). The aperture A of these lenses is small in size, for example 26 or 28 mm in diameter. Typically, such aphakic lenses have a flat radial flange 14.
[0007]
Today, most conventional prescription lenses are relatively flat, single field of view, Ostwald section meniscus lenses, which fit into a flat profile spectacle frame like a window glass.
[0008]
Conventional Ostwald section eyewear is sometimes covered, treated or coated to have specific reflective or anti-reflective properties. The most familiar are sunglasses with a coating that selectively blocks certain parts of the incident light spectrum. Some such lenses are designed to create a preferred color for the viewer by selective selection or absorption of the incident spectral wavelength. Such coatings may involve metal mirror layers and / or stacks of vacuum deposited or sputter coated metal oxides. For example, a coating for sunglasses is disclosed in Auwarter U.S. Pat. No. 2,758,510. As another example, certain multilayer anti-reflective coatings are disclosed in Geller US Pat. No. 4,070,097. See also U.S. Patent Nos. 5,719,705 and 5,959,518. Conventional Ostwald section lenses are sometimes also specially coated to protect the wearer from intense ultraviolet or infrared radiation or laser radiation.
[0009]
Applicants have studied the properties of steeply curved lenses, and have also considered a series of lenses with commonly prescribed plus or minus perspective powers. Applicants have observed that such a lens can, in principle, provide a wide field of view and eye protection. However, the practical application of such wide-field lenses will be hindered by several problems. In general, there are manufacturing and distortion issues, as well as creating a range of typical plus or minus power formulas with or without the general astigmatism correction or "cyl" formula available.
[0010]
A more subtle problem is caused by the large range of surface powers required to provide a general prescription power range. For the lens assumption of FIG. 1, for example, it is understood that the Wollaston section teaches a change in surface power from about 15D to about 20D for a product line perspective power range of + 5D to -8D. This corresponds to a change in surface radius of curvature from about 29 to about 39 mm, representing a large change in the overall size and shape of the lens that is large enough to provide a wide field of view. Such a lens cannot fit into a single frame size like a window glass, but in fact, each prescription itself will dictate its own specific frame size and style. While such unique styles are worthwhile, they are incompatible with providing mass-market eyewear with a consistent appearance.
[0011]
A broad object of the present invention is to provide spectacle lenses with good visual characteristics.
[0012]
It is another object of the present invention to provide a series of steep base curve lenses that are easy to manufacture and supply.
[0013]
Another object of the present invention is to provide a spectacle lens having good visual field characteristics through a wide visual field.
[0014]
Another object of the present invention is to provide a steeply curved lens with less distortion in the peripheral area.
[0015]
It is another object of the present invention to provide eyewear that provides more effective eye protection.
[0016]
It is another object of the present invention to provide a steeply curved lens in general power and astigmatism prescription.
[0017]
It is another object of the present invention to provide lens eyewear for steeply curved prescriptions with a consistent appearance and frame morphology over the prescription range.
[0018]
Some additional advantages may be realized with the teachings of the present invention. The increased field of view allows for the manufacture of eyewear in which the temporal edges are not visible to the wearer (no apparent edges). The teachings of the present invention also allow for the reduction of magnification effects and associated distortion in some steeply curved lenses.
[0019]
Another advantage is that it offers eyewear designers previously unattainable options for lenses with excellent peripheral vision properties in various prescriptions. These include the use of smaller profile lenses, topologically and visually interesting three-dimensional curved lens edges and spectacle rims, and the use of edge thicknesses and surfaces that are more easily hidden from view.
[0020]
Other advantages include the provision of novel sun lenses and protective eyewear tailored to provide specific required apparent properties and specific reflectivity and anti-reflective properties.
[0021]
These and other objects and advantages will be apparent from the following text and drawings.
[0022]
(Summary of the Invention)
In general, the invention relates to eyewear and ophthalmic lens elements therefor. Ophthalmic lens elements may include finished or edge-finished ophthalmic lenses, semi-finished lenses, lens blanks or moldings therefor, as the case may be. Also included are wafers for forming the lenses or lens blanks of the laminate.
[0023]
The present invention is illustrated with reference to FIG. 3, which illustrates some geometric aspects of the steeply curved concentric lens of the present invention. FIG. 3 shows a horizontal sectional view of the left and right eyes (20 and 22 respectively). Each eye is shown to have centers of rotation 24 and 26. The center of rotation is understood to be a volume in the eye with a diameter CD of approximately 1-2 mm, around which the eyes appear to rotate as the direction of gaze changes. As illustrated in FIG. 3, steeply curved left and right lenses 28 and 30 are positioned near the eyes. In this figure, the optical axis of each lens is collinear with the line of sight of each eye and is represented by lines 32 and 34 for each eye. These lines also represent the z-axis of coordinates used later in the text to describe some lens surfaces (the xy plane is perpendicular to the plane of the figure).
[0024]
Lenses 28 and 30 can be generally represented as spherical or spherical bases. In a preferred embodiment, the surface is spherical and has a fixed radius of less than 35 mm for all formula values in the series. In other embodiments, the lens has a spherical back surface and is best described as containing a reference sphere or placed within a defined spherical shell. In each case, the radius of the reference sphere or shell, as well as the location of the lens when worn, is such that the center of the reference sphere or shell is located near or within the center of rotation of the eye. The case where the surface is a sphere of radius R centered on the center of rotation of the left eye is illustrated for the left eye in FIG.
[0025]
The choice of a spherical base of given radius centered on or near the center of rotation of the eye places a constraint on the vertex distance dv, which is plotted as the distance between the face of the pupil 36 and the back 38 of the lens. 3 is illustrated for the left eye. The front surface radius and back surface shape, in conjunction with other design parameters such as lens thickness and refractive index of the lens material, determine the optical properties of the lens, as described in more detail below.
[0026]
Applicants have found that a lens array of the present invention is analyzed and described by a data array of the type shown in FIG. This diagram is called the "Morris-Splat" diagram for the two inventors.
[0027]
In this figure, each dot is at the center of a theoretical ray tracing plot from a lens that has the property of having a grid point at the center of the dot. The "y" axis on the right shows the power of the lens surface in diopters (normalized for a refractive index of n = 1.530). The lower “x” axis indicates the perspective power of the lens at the center of the lens. This corresponds to a positive or negative power prescription of the lens. In this figure, each lens is made of polycarbonate (n = 1.586), has a center thickness of 1.8 mm for a minus power lens, and a center thickness for a plus lens individually at the time of prescription. To be determined, the minimum overall lens thickness is assumed to be 1 mm at the perimeter of a 58 mm diameter lens blank. Each lens is positioned relative to the eye such that the surface is 33.1 mm from the center of rotation of the eye, which is concentric with the lens having a surface power of 16.0 diopters.
[0028]
At each of the individual grid points, ray tracing results appear for eye rotation angles up to 40 degrees. The black area of each grid point represents the area of each lens where the RMS (root mean square) power error for the prescription is less than 0.125 diopters, allowing adjustment to 0.375 diopters. The RMS power error is defined mathematically below. This criterion is considered to be an excellent indicator of lens performance.
[0029]
The fully filled circle in FIG. 4 represents a lens with an RMS power error of less than 0.125 diopter for eye rotation greater than 40 degrees in any direction. For dots with an annulus around, the RMS power error rises above 0.125 diopters at some intermediate rotation angle of the eye, and falls back below its threshold once it enters a small angular area.
[0030]
The elliptical contour of the locally largest dot approximately corresponds to the Chernning ellipse generated for the special case of the lens parameters chosen by the applicant. From previous experience, to produce high quality lenses, the surface of spherical lenses (lenses with spherical surfaces on the front and back) must follow the Chernning ellipse. However, the Morris-Splat diagram shows that there is a nearly horizontal area in which a good lens can be manufactured for proper selection of lens parameters. It is known that flat spherical lenses with high quality optical properties can be manufactured over a wide range of surface curvatures (the fact indicated by the large vertical line of dots near zero perspective). Many such lenses are available on the market today. The novel idea illustrated in the Morris-Splat diagram is that with the proper choice of lens parameters, a single steeply curved surface or spherical reference surface or shell can be used to produce high quality spherical A lens can be manufactured. The low RMS power error region of the lens using a surface power of 16 diopters (grid points on line 40) has a wide angular range (substantially entirely or completely filled circles) ranging from at least -6 to +4 diopters. Note that 95% of all formulations fall in this range. Thus, it is possible to produce high quality ophthalmic spherical lenses for a wide range of useful formulations using a single, appropriately selected high number surface or base curve. In addition, as can be seen from FIG. 4, slight departures from single power or exact concentricity can be achieved, while still providing excellent lens quality and a lens shape that is sufficiently consistent so that the same frame style can be used. .
[0031]
FIG. 5 illustrates a series of lenses with excellent optical quality of a preferred embodiment of the present invention. In this embodiment, the surface is selected to be about 16D ± about 1 / 2D. This range is located between the horizontal lines 50 and 52. Particularly preferred embodiments provide a series of lenses having a prescription ranging from -2D to + 2D (areas 54), -6D to + 4D (areas 54 and 56), or -8D to + 5D (areas 54, 56 and 58). Is done.
[0032]
For comparison purposes, a portion of the Wollaston section of the Chernning ellipse 60 for this particular case has been superimposed on the diagram of FIG. The perspective power range represented by the front curve and the horizontal block shows that the surface power has a variation of 5D at the perspective power of −8D to + 5D, and the curvature at the center of the perspective power range is much steeper. This figure shows that it is inconsistent with the teaching of the Chernning ellipse shown.
[0033]
Preferred embodiments of the present invention include a series of ophthalmic lens elements defined by a single reference sphere concentric with the center of rotation of the wearer's eye, where the sphere is between 25 mm and 50 mm, more preferably Has a radius of curvature of 30-35 mm, and most preferably about 33 mm ± about 1 mm.
[0034]
Advantageously, an appropriate prescription power and cyl correction are applied to the series of lens elements. In embodiments where the front surface is spherical, the back surface is configured to provide appropriate perspective power and cyl correction. In a preferred embodiment, the series of lens elements may include perspective powers within the above range in 1 / 4D increments. Each power storage lens element is given each of the various common astigmatism prescriptions of 0D to -2D, for example, in 1 / 4D increments. It will be appreciated that, since the lens element is spherically symmetric, the angle of the cyl correction can be selected by appropriately rotating the lens element during edge milling and glazing.
[0035]
Conventional astigmatism correction is based on a toroidal surface that is often described in relation to the principal meridian, i.e., it is an orthogonal meridian centered on the lens optical axis, and has maximum and minimum curvature trajectories. Represent. Both barrel toroids and donut toroids have been used to provide cyl correction. As described below, Applicants have developed new astigmatism correction surfaces for steeply curved lenses, which are placed between the barrel toroid and the donut toroid. Each of these has the same main meridian and the same power along the main meridian. Two such planes are the "full circular meridian" plane and the "mean toroid" plane, described in detail below.
[0036]
The shape of the lens of the present invention will be described. The term "steep curvature" is used in this context to describe the overall shape of a lens or reference sphere or shell. In certain embodiments, the curvature can be located inside or outside the lens, or quantified as the average radius of curvature of the surface or spherical shell that includes the surface of the lens.
[0037]
The lenses of the present invention are further characterized in their overall shape by a large viewing angle, which is often expressed as the angle between the optical axis and the temporal or nose tip. According to a preferred embodiment of the invention, the lens is at an angle centered on the center of the spherical surface, which angle is greater than 80 °, and in the preferred embodiment is greater than 100 °. Of course, if the lens is optically usable in these peripheral regions, it will be understood that such an angle is indicative of the field of view of the lens.
[0038]
The unique phase shape of the lenses of the present invention is further characterized by sagittal or "hollow" depth, which is generally a measure of the three-dimensionality of the lens and lens edge. These depths relate to the distance between the front parallel plane of the lens and the point at the extreme end of the temporal, as explained below. According to a preferred embodiment of the present invention, there is provided a lens having an average radius of less than 50 mm centered on the center of rotation of the eye and a hollow depth of at least 8 mm. In a particularly preferred embodiment, the radius of the surface is about 33 mm ± about 1 mm and the hollow depth is at least 10 mm.
[0039]
The invention also includes a method for providing prescription eyewear. These methods use lens elements with steep curvature. The preferred embodiment uses a surface within a spherical shell having a thickness of 2 mm or less and a radius of 50 mm or less. A back surface is formed in the lens element such that the lens element has a prescribed power and a prescribed astigmatism correction. The lens elements are positioned relative to the wearer such that the center of the spherical shell is located at or near the center of rotation of the eye, which is a series of lens elements having various perspective powers, including a prescribed perspective power. By fitting into a frame having a standard opening corresponding to a common spherical shell radius. Eyewear provides prescribed power and astigmatism correction over the entire visual fixation range of the wearer.
[0040]
The invention also includes specially designed spectacle frames. In a preferred embodiment, there is provided a spectacle frame suitable for use in a series of ophthalmic lenses, each of the lenses having a spherical surface having a single radius of 25 mm to 35 mm and various common prescriptions associated with the spherical surface. And a second surface selected to provide In a preferred embodiment, the frame is adapted to support the left and right lenses of the wearer such that the centers of the spherical surfaces are located at or near the centers of rotation of the left and right eyes, respectively. The spectacle frame may include a temporal component and a rim portion for engaging the left and right lenses. The rim portion engaging each lens may be formed in the form of a closed curve on a reference sphere having a radius approximately equal to the radius of the spherical surface. In such a spectacle frame, the extreme points of the nose and the temporal end of the closed curve may span an arc greater than 90 ° with the apex centered on the spherical surface.
[0041]
The spectacle frame may include a left head part, a right head part, and a nose bridge. In a preferred embodiment, the nose bridge has an adjustable length that allows the lens spacing to be adjusted horizontally to center the spherical surface at the center of the eye. In another embodiment, a rimless frame with novel attachments and hinges for supporting temporal components is provided, wherein the hinges are adapted to attach directly to a reference spherical surface at the temporal edge of each lens. Is done.
[0042]
The present invention also includes novel lens edge machining that can be used with steeply curved lenses, especially lenses having at least one spherical surface with a radius of about 31 mm to 33 mm.
[0043]
In such a case, the lens may be edged such that the lens edge surface is substantially perpendicular to the spherical surface of the lens. Eyewear made with such lenses can be rimless, and the edge surface can be essentially invisible to the wearer. This is because when the gaze of the wearer is thrown in that direction, the edge surface is substantially on the line of sight of the wearer. Further, the edge appearance to an external observer can be minimized. Such an edge surface can be created by a mill rotated about an axis that intersects the center of curvature of the spherical surface. In a preferred embodiment, the edge surface is cut such that the surface makes a small arc about the center of curvature of the spherical surface, the arc being in any plane including the optical axis of the lens.
[0044]
The present invention also includes a method for making a steeply curved lens element adapted to be attached to eyewear. The method may include molding a lens blank having a radius of curvature of less than 35 mm along a principal meridian over a substantial portion of its front surface. After molding, the back side is cut on a molded lens blank, which, along with the front side, provides a non-zero prescription perspective power. Finally, the lens blank is edged into an edged lens having a maximum hollow depth of at least 8 mm. The cut back surface, along with the front surface, may be designed to provide non-zero astigmatism correction to the wearer.
[0045]
In one embodiment, a progressive surface power addition is formed on the surface of the lens blank. Alternatively, the progressive surface power addition can be incorporated into the back surface cut into the lens blank.
[0046]
Another aspect of the invention relates to a steeply curved sun lens, such as a lens having a spherical optical surface with a radius of curvature of less than 35 mm as described above. Sun lenses are made by coating and / or coloring the steeply curved lenses of the present invention. In a preferred embodiment, the optical surface (eg, surface) may be coated with a generally blue, partially reflective, dielectric stack in a particularly preferred embodiment. The surface coating may be a sputter-deposited multilayer coating composed of alternating layers having relatively high and relatively low refractive indices. In particular, the surface coating can be a stack of silicon and zirconium oxide layers, at least one of the zirconium oxide layers having a thickness greater than about 10 nm. The coating is designed so that its reflectivity begins to decrease for incident light at wavelengths above about 480 nm and remains relatively low in the near infrared.
[0047]
The invention also relates to protective eyewear including left and right lenses, each having a spherical surface. Each spherical surface preferably has a radius of curvature of about 31 mm to 35 mm. The frame supports the lenses on the wearer's face such that the center of the spherical surface of each of the left and right lenses is approximately positioned at the center of rotation of the left and right eyes.
[0048]
Multi-layer coatings can be formed on each lens to at least partially block the radiation incident on the lenses from transmitting to each eye. The layer has a selected refractive index and thickness to at least partially block at least one selected portion of the spectrum of the incident radiation. In sun lens embodiments, ultraviolet light may be at least partially blocked. Protection from laser radiation can also be provided by eyewear in industrial or military settings. In this case, a coating and / or dye is provided to block the laser light in a selected spectral range. In particular, infrared laser radiation can be at least partially blocked. Incident laser radiation is blocked enough to reduce its power level to eye safety levels. Off-axis incident radiation has an optical path that is obstructed by the stack, absorbed by the dye, and / or does not reach the retina.
[0049]
In an embodiment of the protective eyewear of the present invention, each lens is preferably positioned in the orbit so as to stand between radiation coming from all directions reaching the retina, while advantageously providing a wide field of view to the wearer of the field of view. From the nasal margin to the temporal region of the orbit and from the lower margin of the orbit to the upper margin.
[0050]
The above is intended only as an overview of the invention, the scope of the invention being determined by the language of the claims and their equivalents.
[0051]
(Detailed description of drawings and examples)
outline
I. Basic lens geometry
II. Correction of astigmatism
III. Magnification effect and distortion reduction
IV. Lens manufacturing
V. Calculated performance of lens design example
VI. Fitted lens and spectacle frames
VII. Coatings, sun lenses and protective eyewear
I. Basic lens geometry
The basic geometry of a lens manufactured according to the present invention will first be discussed. 6A, 6B and 6C show a front view, a side view and a top view, respectively, of an edged lens 100 according to the present invention. The origin 102 in FIG. 6A is the location of the optical center of the lens, and is the design location of the pupil center when worn. The edged lens profile 104 is shown in the front perspective view of FIG. 6A. FIG. 6B shows the temporal edge 106 and the nose edge 108 of the lens. FIG. 6C shows the upper edge 110 and the lower edge 112 of the lens. In the embodiment of the lens of FIG. 6, the surface of the lens is a steep spherical curve, the rightmost end of which is indicated by line 114.
[0052]
The steep spherical curvature of embodiments of the present invention can be designed into the lens in a variety of ways. In the preferred embodiment discussed above, the surface of the lens element is a single radius sphere centered at or near the center of rotation of the eye. Alternatively, the back surface of the series of lens elements is a steep, spherical surface that can be centered at or near the center of rotation. In these embodiments, the other surface has a variable curvature, and the curvature is selected to provide the wearer with at least a suitable perspective power. For example, if a 16D spherical surface is selected for the series of lens elements, the back surface having a curvature of 20D on its major meridian and 18D on its minor meridian will provide a perspective power of -4D by -2Dcyl. Used for Alternatively, if a constant radius surface of the lens element is placed on the back surface, the corresponding surface selected for a particular prescription may be placed on the front surface.
[0053]
In another alternative, the lens element or surface is restricted to be located within the spherical shell. This geometry is shown in FIG. Two concentric spheres 154 and 156 are defined by the center of point P and two radii r1 and r2, where r2> r1. At the same time, the sphere defines a shell S. Lens 158 is shown having a point Q at the extreme end of the nose and a point O at the temporal end. The lens surface 160 is located within the shell S.
[0054]
The surface of the optical lens element according to the invention may be spherical, toric or rotationally symmetric non-spherical. To further improve the field of view, the front and / or back surface of the optical lens element according to the invention may have a shape deviating from a spherical shape to improve the optical performance and / or the apparent appearance. As explained above, the front and / or back surface can be derived by solving an optimization task to minimize the selected merit function, which represents a measure of the optical aberration visible to the lens wearer. Alternatively or additionally, the correction may improve the apparent appearance of the lens element. Alternatively, the surfaces within the shell may be multifocal progressive lenses, as described in more detail below.
[0055]
In a preferred embodiment, the lengths of radii r1 and r2 differ by no more than 2 mm, and in a more preferred embodiment one of the radii is about 33 mm and the difference in length of r1 and r2 is no more than about 0.1 mm. The surface is at an angle OPQ greater than 75 °, preferably greater than 90 °, more preferably greater than 100 °. This angle is a measure of the wide field of view provided by the lens.
[0056]
Alternatively, the lens may be defined to lie entirely within a shell defined in a manner similar to shell S of FIG. 7, with a difference in length between r1 and r2 of less than 6 mm.
[0057]
Additionally and alternatively, a lens may be defined as including a portion of a steeply curved sphere, such as a portion OQ of a sphere having a radius r1 of FIG. The reference sphere may be a sphere located midway between the front and back surfaces of the lens element. In an embodiment of the present invention, this steeply curved sphere defines the abutment surface of two lens wafers manufactured according to US Pat. No. 5,187,505, which is otherwise incorporated herein by reference. I can do it. In such a case, the ophthalmic lens or lens blank is formed as a laminate of the back and front wafers. It will be appreciated that because the abutment surface of the wafer is spherical, the wafer can be rotated to achieve the desired orientation of the cyl correction applied to one of the surfaces. This is particularly useful in providing progressive lenses.
[0058]
Another aspect of the novel geometry of the lens element of the present invention is shown in FIG. A lens 170 having a steep spherical curvature and substantially concentric with the center of rotation 172 of the eye is shown. The front parallel plane P contacts the spherical surface 174 of the lens. The optical axis 176 of the lens is perpendicular to the plane P and passes through the center of rotation of the eye. The back side is identified by reference numeral 178. The lens extends in a temporal direction to a temporal edge 180. The new geometry of the lens is defined in part by the hollow depth ZH, which is the vertical distance between the back surface 178 of the lens and the edge 180 at the optical axis. The relevant dimension ZF is the distance between the front parallel plane P and the edge 180.
[0059]
It is beneficial to consider the peripheral optical properties of the lens of the present invention, such as distortion. In such a case, as shown in FIG. 9, reference may be made to the lens characteristics located inside or outside the half-angle φ cone centered on the optical axis O. In FIG. 9, θ is shown as a 30 ° angle. In a preferred embodiment of the invention, the series of lens elements has a surface astigmatism of less than 0.125D through a cone defined by an angle θ of at least 25 °.
[0060]
The lens elements of the present invention may have an RMS power error for central vision (defined below) of less than 3 / 8D for eye rotation angles of less than 30 [deg.]. Further, the lens element may have an RMS power error for central vision less than 1 / 2D for eye rotation angles greater than 30 ° and less than 40 °. Finally, the lens element may have an RMS power error for central vision that is less than 3 / 4D for an eye rotation angle that is greater than 40 degrees and less than 50 degrees.
[0061]
In a preferred embodiment, the lens element has an RMS power error of less than 3 / 8D for a fixed position angle of ± 5 [deg.] For a peripheral field where the eye is rotated and fixed at a 30 [deg.] Angle in the temporal direction. It can be configured that the power error is less than 0.65D for a fixed position angle ± 10 ° and the RMS power error is less than 1.0D for a fixed position angle ± 30 °.
[0062]
Some features of the present invention and a comparison with a conventional lens are illustrated in FIG. FIG. 10 (a) shows a plan view of a selected contour for a conventional lens and the steeply curved spherical lens of the present invention. A conventional 6D base lens 200 is shown in FIG. 10 (b), and a 16D base lens 202 according to the present invention is shown in FIG. 10 (c), both of which have the same planar profile as FIG. 10 (a). The apparent field of view is measured between edge rays centered on the pupil center C on the pupil plane. Conventional base 6 lens 200 has an apparent field of view of about 105 °, while lens 202 has an apparent field of view of about 130 °. If a larger lens blank and a planar profile are used, a 16D base lens 204 of approximately the size shown in FIG. 10 (d) can be manufactured. Such a lens may extend horizontally from the nose margin 206 to the temporal margin 208 of the orbital region producing an apparent field of view of about 170 °. Such lenses have no temporal edges visible to the wearer when staring straight. In addition, the temporal lens edge thickness 210 is curved backwards so that it is not easily visible to others, thus improving the apparent appearance of the lens. Finally, the back surface 212 of the lens moves away from the normal length eyelashes for a wide range of prescriptions.
[0063]
II. Correction of astigmatism
The steeply curved spherical lens according to the present invention creates certain problems when cyl correction is part of the wearer's prescription. Normal toric backs may not provide acceptable performance. In particular, conventional torics do not work well at the periphery of steeply curved lenses.
[0064]
The ideal backside for cylRx (ignoring such things as ray tilt) will have a certain surface astigmatism that is suitable for prescription. No such surface exists. The toric surface can be manufactured near this ideal. There are two standard types of toric surfaces, sometimes called donut toric and barrel toric. Each is obtained by sweeping a circular arc around a fixed axis. A donut toric if the radius of the circle is smaller than its maximum distance to the fixed axis, otherwise a barrel toric. Both types of torics have a circular cross section along two main meridians. Because of this (and symmetry), the tangent power is correct everywhere along these meridians. In addition, this type of toric has a "preferred" meridian with the correct sagittal power. For donut torics, it is the lower tangent meridian; for barrel toric, it is the upper tangential meridian. Zero tangents and sagittal errors mean that the surface astigmatism is equally zero along the preferred meridian.
[0065]
A conventional toric example of a steeply curved lens is shown in FIGS. 11A and 11B. In both examples, for a nominal 2 cyl, the tangent frequency is 18 diopters (＠ n = 1.530) on the equatorial 180 ° meridian and 20 diopters at 90 °. The plot is 45 mm in diameter and has a contour of 0.1 diopter. Circular main meridian curvatures C1 and C2 are shown in FIG. 11C. C1 and C2 intersect at the center point of pole P at an angle of 90 °. It will be appreciated that other "minor" meridians may be defined as extending radially from the center point.
[0066]
The preferred axis is apparent from the plot in FIG. The tangent and sagittal plane powers forming angles of 0-90 degrees around radii of 0, 10 and 20 mm from the center are shown in FIGS. 12A-12D.
[0067]
From these figures, it can be noted that both donut toric and barrel toric have the correct tangent power at 0 and 90 degrees for all radii. The donut toric has the correct sagittal power at 0 degrees, but has an error at 90 degrees, and the error increases with radius. The barrel toric has the correct sagittal power at 90 degrees, but has an error at 0 degrees, which increases with radius.
[0068]
Some are obviously asymmetric about both of these torics, and each of them has a preferred meridian. However, there are functions that maintain the correct tangent power along the main meridian, but treat the sagittal power more symmetrically. The way to construct a function with the desired tangential behavior is to force the cross section along any meridian to be circular. The function will have the following form:
[0069]
(Equation 1)

Here, R (θ) is a radius of curvature along the θ meridian, and r = √ (X ² + Y ² ). The values of R (0) and R (90) are fixed at the desired tangent power, and the power at intermediate angles is determined by applying interpolation to these limits. The form of interpolation comes from the realization that the form of the frequency profile described above is approximately sinusoidal. Thus, a good first order approximation for R (θ) would be:
[0070]
(Equation 2)

Where P is the tangent power and n is the refractive index required to convert the power to curvature. To add more control over the sagittal behavior, additional Fourier terms can be added to the interpolation. To further increase the control over tangential behavior, the power can be a polynomial in r. For a simple surface, no additional degrees of freedom are required. The plots in FIGS. 13A, B show the tangent and sagittal power as a function of angle as indicated above for the toric. Note that the tangent error at intermediate angles is less than donut toric and greater than barrel toric. The sagittal powers are correct for r = 0 at 0 and 90, but start to chip off on both meridians more or less symmetrically with increasing radius. For surfaces that are not axisymmetric, there is a weak contribution from the angular aspect to the tangential curvature. This is because the normal vector is not on the same plane as the circular cross section.
[0071]
Another way to create an "unbiased" cyl correction is to average traditional donut and barrel torics. This gives results similar to those for a surface constructed from a circular meridian. Angle plots for the averaged toric are shown in FIGS. 14A and B, where Z = aBZB + (1-aB) ZD, where Z is the lens surface height and ZB is the conventional barrel toric. The surface height, ZD is the surface height of a conventional donut toric, and aB is a weighting factor such that 1>aB> 0. 14A and 14B show a specific case where aB = 0.5.
[0072]
Although difficult to assert from the plot of FIG. 14, there is a significant difference in the angular behavior of the tangent and sagittal powers for these circular meridians and the averaged toric surface. The contour plot of FIG. 15 compares the surface astigmatism of the averaged toric and circular meridian functions. The plot has the same 0.1 diopter profile and 45 mm diameter as in the example above.
[0073]
Astigmatism behaves simpler for the circular meridian plane than for the average toric. To show the effect of adding the Fourier term to the angle interpolation, one extra coefficient can be adjusted to "round up" the elliptical contour. FIG. 16 shows the result. Note that the meridians still all have circular cross-sections and only the angle interpolation has been slightly modified.
[0074]
The circular meridian and the mean toric surface have additional properties to note. The surface astigmatism of a surface at any point deviated from the principal meridian is less than the larger of the barrel toric or donut toric surface astigmatism at the same point. In addition, the mean toric or circular meridian plane lies between barrel toric and donut toric of the same formula (with intermediate Z values).
[0075]
While the torics described above are preferred for use as the back surface of the lens of the preferred embodiment of the present invention, conventional torics or generalized torics can be used to provide the lens.
[0076]
Alternatively, surface correction of the lens element of the present invention may be provided by manufacturing the back surface according to the following symmetric polynomial:
[0077]
[Equation 3]

[0078]
Many measurements of optical aberration of a lens are defined as follows.
[0079]
(Equation 4)

Here, ε is a focus error matrix, which can be written as follows.
[0080]
(Equation 5)

Here, when a set of orthonormal groups is selected, ε12 = ε21.
[0081]
When calculating these terms by specifically considering the optical properties of the lens, the terms optical average power error, optical cyl error, and RMS optical power error apply.
[0082]
The merit function can be selected from the following functions depending on the specific application of the optimized lens.
[0083]
(Equation 6)

Here, the sum is calculated with respect to the eye rotation speed θ.
[0084]
In the case of M4, various shake measurements are used depending on whether the sample point θ represents a horizontal, vertical or diagonal rotation from a “straight” position. This mode may provide some generalization of the aspheric “minimum tangent error” design strategy.
[0085]
Modes M3 and M5 represent the "minimum astigmatism error" and "minimum average power error" strategies, respectively.
[0086]
In a further embodiment, a term in the merit function representing the appearance of the lens may be included. For example, instead of using M alone, a modified merit function may be defined by the following equation:
[0087]
(Equation 7)

Here, ηθ indicates the number of rotations θ of the eyes of the sample considered in M, r is the specific lens radius, and V is the lens volume going to radius r. It can be seen that the coefficient λ weights the average lens thickness.
[0088]
III. Magnify and reduce distortion
The spectacle lens reduces or enlarges the object seen through it. This is because the main surface of a conventional spectacle lens is placed close to the crystalline lens and does not match the entrance pupil of the eye. In general, a lens with a positive power makes the object appear large, and a lens with a negative power makes the object small. Magnification also changes the direction of recognition of the object in the peripheral field of view so that the apparent field of view is different from the true field of view seen through the lens.
[0089]
In addition to magnification, spectacle lenses further distort the shape of objects seen through it. When looking straight ahead, the minus lens causes a so-called "barrel distortion", in which the rectangular object is compressed at the periphery and the square looks like a barrel. Conversely, positive power lenses "cause pincushion distortion and stretch the corners of the square.
[0090]
Both of these effects increase the perceived loss of size, shape and position of the object. Ophthalmic optics textbooks teach that correcting distortion in spectacle lenses is impractical, and does not mention that it is desirable to reduce the magnifying effect. Nevertheless, one of the advertised advantages of the field of view of contact lenses is that the close fit of the lens reduces the effects of magnification and distortion and allows the field of vision to be corrected more naturally. Magnifying and reducing distortion of spectacle lenses may be desirable where possible.
[0091]
For distant objects, the magnification effect is defined by:
[0092]
(Equation 8)

Here, d (dv in FIG. 3) is the distance from the back surface of the lens to the entrance pupil of the eye, Fv is the vertex frequency of the back surface expressed by diopter, t is the thickness expressed in meters, and n is n The refractive index, and F1 is the surface power expressed in diopters.
[0093]
The portion of the equation in the first parenthesis is often called the "power factor" to indicate how much magnification is due to lens power. If d equals 0, the frequency coefficient will be equal to 1. In other words, in the case of a lens that is in contact with the eye, the magnification by this power is very small, which is the case with a contact lens. This term is greater than 1 for a plus lens and less than 1 for a minus lens because the spectacle lens is positioned away from the eyes to avoid contact with the eyes, eyelids or eyelashes. In other words, a plus-power spectacle lens tends to enlarge and a minus lens tends to shrink. Where appropriate, the term "magnification effect" is used to describe both enlargement and reduction.
[0094]
The part of the equation in the second parenthesis is usually called the "shape factor" because it indicates how the magnification changes with the thickness and curvature of the lens. If the lens has no thickness, t will be equal to 0 and this term will be equal to 1. With an ideal “thin lens” of the third optics, there is no magnification effect due to the shape. Contact lenses approach this situation because they can be made extremely thin. This term is always greater than one, because spectacle lenses are made quite thick to avoid damage and always have a positive surface curvature. In other words, all positive meniscus spectacle lenses tend to enlarge due to their shape.
[0095]
In order to eliminate the expansion effect, the equation must be set equal to 1, so the product of the frequency coefficient and the shape coefficient must be equal to 1. Since both the power factor and the shape factor of the plus lens are greater than 1, their product cannot be 1 and the positive meniscus form of plus lens cannot eliminate the magnification effect. On the other hand, since the power coefficient of the minus lens is less than 1 and the shape coefficient is larger than 1, it is possible to cancel these coefficients.
[0096]
To do this, we need to solve this equation for unit expansion. When this is done, the following relationship is obtained:
[0097]
(Equation 9)

This equation specifies the lens thickness that eliminates the magnifying effect of the glasses. It works well if the second principal surface of the lens is placed on the entrance pupil of the eye. Achieving this at a practical thickness requires two things: a minus lens power and a very steep curve.
[0098]
(distortion)
According to tertiary theory, distortion can only be removed in steeply curved lenses, which is impractical. Jalie, M .; See "Principles of Ophthalmic Lenses", 4th edition, page 462.
[0099]
Third-order theory actually requires a back surface curve in excess of 35 diopters, which is nearly concentric near the entrance pupil of the eye, and such surfaces are practically impractical. In a truly concentric lens design where both surfaces are concentric near the entrance pupil of the eye, there is no distortion. This is because, due to the symmetry of the lens, all of the light beams from the oblique object will encounter the same plane tilt as from the central object. Extremely steep curves are not required for concentricity in the vicinity of the entrance pupil of the eye, but even a somewhat flat curve may result in distortion when combined with a lens having a principal surface located close to the entrance pupil. It was found that it was dramatically reduced. This is done by a lens designed to reduce the reduction in the minus power lens, resulting in a lens that is arranged substantially concentrically about the center of rotation of the eye.
[0100]
In fact, it is highly desirable to arrange the lenses concentrically about the center of rotation of the eye. This is because this improves the symmetry of the lens with respect to the eye when the eye is rotated to look at objects in the peripheral field of view, resulting in improved resolution. If one strictly requires that one surface of the lens be arranged concentrically about the center of rotation of the eye, one can derive a thickness that virtually eliminates distortion. In this case, a specific type of equation for lens thickness is required.
[0101]
For example, for a lens whose surface is concentrically arranged around the center of rotation of the eye, t is determined by the radius of the surface, the wearing distance, the refractive index, the back vertex power, and the distance from the center of rotation of the eye to the entrance pupil You can ask. in this case,
[0102]
(Equation 10)

here,
[0103]
(Equation 11)

Is the shape factor of the lens, r1 = radius of the surface, df = distance from the lens surface to the plane of the entrance pupil, and Ke is the entrance pupil of the eye from the center of rotation of the eye as shown in FIG. Is the distance to
[0104]
17A to 17C illustrate the advantages of this type of design. FIG. 17A depicts a larger grid visible from some large distance, such that the grid extends 45 ° to the left and right of the viewer. FIG. 17B is a calculated image of what a person wearing a conventional -5.00D lens sees, where the grid appears small and the shape appears distorted. FIG. 17C shows a calculated image seen by a wearer of a lens designed to eliminate distortion according to the above equation. This image looks almost identical to the original object.
[0105]
IV. Lens manufacturing
The ophthalmic lens element according to the present invention may be made from any suitable material. Polymeric materials may be used. The polymeric material can be of any suitable type. The polymer material may include a thermoplastic material such as a polycarbonate type or a thermosetting material such as diallyl glycol carbonate, for example, CR-39 (PPG Industries) may be used.
[0106]
The polymer article may be a cross-linkable polymer molding composition, for example, as described in US Pat. No. 4,912,155 or US Patent Application No. 07 / 781,392, the entire disclosure of which is incorporated herein by reference. Can be formed from an object.
[0107]
The polymeric material can include dyes, including, for example, photochromic dyes, which can be added to the monomer formulation used to make the polymeric material.
[0108]
The optical lens element according to the invention may further comprise additional standard coatings, including electrochromic and / or liquid crystal coatings, on the front or the back. The lens surface may include an anti-reflective (AR) coating, which may be, for example, of the type described in US Pat. No. 5,704,692, the entire disclosure of which is incorporated herein by reference. Partially reflective coatings can be applied to the lenses to make sunglass lenses or to provide the desired apparent effect. The surface of the lens may alternatively or additionally include an abrasion resistant coating of the type described in US Pat. No. 4,954,591, the entire disclosure of which is incorporated herein by reference.
[0109]
The front and back surfaces may be one or more of those conventionally used in molding compositions such as reaction inhibitors, eg, dyes including the thermochromic and photochromic dyes described above, polarizers, UV stabilizers, and materials capable of changing the refractive index. Surface treatment.
[0110]
FIG. 18 shows a mold suitable for manufacturing a lens element according to the teachings of the present invention. The mold includes a front mold part 300, a back mold part 302, and a closed flange part 304. The lens element may be formed in the cavity 306 between the molds by injecting a liquid lens material through the port 308. Air escapes through port 310. When the lens element cures, the mold parts are separated. The lens element will be observed to have a radial flange 312 when removed from the mold, which will be removed in later processing.
[0111]
A method and apparatus for molding a lens element of the present invention is described in “Methods of Molding Thermoplastic Lenses and Steeply Curved and / or Thin Lenses Made Thereof” filed Sep. 8, 2000. No. 09 / 658,496 to Kingsbury et al., The contents of which are incorporated herein by reference in its entirety.
[0112]
V. Calculated performance of lens design example
(Example 1)
Table 1 shows a comparison of the calculated performance of a polycarbonate lens made according to the present invention and a conventional low base curve lens.
[0113]
[Table 1]

[0114]
(Example 2)
FIG. 19 shows a series of steeply curved spherical lens elements of -6D, -3D and + 3D power (FIGS. 19 (a), 19 (c) and 19 (e), respectively) and corresponding low base curves Sola. FIG. 19 shows a calculated comparison with Perma-Poly® material lenses (FIGS. 19 (b), 19 (d) and 19 (f), respectively).
[0115]
The steeply curved spherical lens element has an essentially identical 16D spherical surface, as shown in lens section 400. In general, steeply curved spherical lens elements improve peripheral distortion. The lenses of FIGS. 19 (a) and 19 (c) also show low RMS power errors at minus prescription.
[0116]
(Example 3)
FIG. 20 shows a calculated comparison of two steeply curved spherical lenses with 16D front surface-3D perspective power and -2 back surface cyl correction.
[0117]
The lens of FIG. 20 (a) has a conventional donut torus back, and the lens of FIG. 20 (b) has a full circular meridian back of the type described above. The latter has better RMS power error and some improvement in distortion.
[0118]
(Example 4)
The last set of examples (FIGS. 21 and 22) shows a comparison between a conventional base curve progressive lens and a progressive lens according to the present invention.
[0119]
FIG. 21 compares the far-field characteristics of a conventional curved Sola XL progressive lens with a progressive lens similar to a lens element having a steeply curved (16D) base curve.
[0120]
FIG. 22 compares the near-field characteristics of the Sola XL progressive lens and the steeply curved lens of FIG.
[0121]
Generally speaking, a progressive lens made in accordance with the present invention is characterized by a steeply curved reference sphere or spherical shell that is approximately concentric with the center of rotation of the wearer's eye in the wear position. Such a lens has an upper observation zone for the far field, a lower observation zone for the near field having a higher power than the upper observation zone, an intermediate zone connecting the upper zone and the lower zone, and an upper zone. Power varies between the lower zone and includes a relatively low surface astigmatism corridor.
[0122]
In one embodiment, the steeply curved reference sphere corresponds to the surface of the central portion of the upper viewing zone. In another embodiment, the progressive surface is on the surface of the lens and is located in a steeply curved spherical shell less than about 2 mm thick. In either embodiment, the radius of curvature of the shell or reference sphere can be less than 50 mm, preferably about 30 mm to 35 mm, and most preferably about 33 mm ± about 2 mm. A suitable surface design for a progressive lens is shown, for example, in Applicant's 08 / 782,493, filed Jul. 10, 1997, now U.S. Pat. No. 5,861,935. It is.
[0123]
VI. Fitted lens and spectacle frames
The spectacle frame used in the present invention is adapted to hold the lens of the present invention in the approximate position shown in FIG. The spectacle frame may be rimless, partial rim, or full rim.
[0124]
In a preferred embodiment, the lens does not inherently tilt or exhibit a wrap angle when mounted on a spectacle frame. The spectacle frame may include an adjustable mechanism for changing the position of the optical axis of the lens to correspond to the axis of the wearer's straight field of view.
[0125]
FIG. 23 is a perspective view showing an eyewear 400 including the lenses 402 and 404 of the present invention and an eyeglass frame. An apparently preferable product is obtained depending on the lens shape. The spectacle frame of FIG. 23 is shown with a rim portion 406 and temporal components 408 and 410. The rim of the spectacle frame surrounding each lens is adapted to correspond to a closed curve located on or near the steeply curved reference sphere of the lens. This consistency of curvature over the prescription range allows a single frame or frame design to be adapted for any prescription in this range.
[0126]
FIG. 24 is a side view of the eyewear of FIG. 23 when worn on a wearer's face. This figure shows another aspect of the appearance of the wearer obtained by the steeply sloping curvature of the lens and the complex three-dimensional shape of the lens edge. This figure shows that a relatively small size lens provides a wide field of view and good protection for the eyes.
[0127]
Figures 25A and 25B are front views of an eyewear embodiment 412 according to the present invention, showing some mechanical aspects of the present invention. The eyeglass frame of the embodiment of FIG. 25 includes a nose bridge 414 and hinged temporal pieces 416 and 418. When these components are combined, a three-member rimless spectacle frame is configured.
[0128]
Temporal components 416 and 418 include hinges 420 and 422 and mounting tabs 424 and 426. In a preferred embodiment, tabs 424 and 426 are mounted on the spherical surface of the lens. It will be appreciated that these mounting surfaces are placed in a consistent position and angular relationship to the frame, regardless of the prescribed power and the cyl correction of the lens. Similarly, tabs 428 and 430 of nose bridge 414 can be surface mounted to respective surface edges of the lens.
[0129]
The nose bridge 414 is shown in cross-section in FIG. 25B. Advantageously, the nose bridge is made with an adjustable length to compensate for different pupil distances (PD in FIG. 3) normally found in different wearers. This adjustable feature allows the optical axis of the lens to be aligned with the viewing axis of the wearer's eyes. One mechanical structure suitable for producing this adjustable feature is shown in FIG. 25B, but it is understood that other combinations of moving or flexible structures can be adapted for this purpose. In the embodiment of FIG. 25B, each of tabs 428 and 430 are held by members 432 and 434, respectively, which are inserted at opposite ends of tube 436. Locking screws 438 and 440 hold members 432 and 434 in place. The locking screw can be loosened to allow the nose bridge length to be adjusted by sliding members 432 and 434 in the tube to various positions.
[0130]
FIG. 26 (a) is a plan view of an eyewear embodiment 500 of the present invention. Eyewear is a rimless type. The left lens 502 and the right lens 504 are steeply curved and edge processed lenses. In a preferred embodiment, these lenses each have a generally spherical front optical surface 506 having a radius of curvature of less than 50 mm, preferably less than 35 mm, as described above. In the wearing position, the center of the radius of curvature of the spherical surface of each lens is located substantially at the center of rotation PL, PR of each eye of the wearer.
[0131]
The lenses 502 and 504 are connected by a nose bridge 508 to support the lenses on the wearer's face. Left and right temporal components 510 and 512 are provided and are attached to the temporal edges of the left and right lenses, respectively. A preferred method of attachment is discussed in connection with FIG.
[0132]
FIG. 26 (b) is a detail of the embodiment of FIG. 26 (a) showing the attachment of the right temporal part 512 to the right lens 504 by the right attachment part 514 and the hinge 516. In a preferred embodiment, the right fitting is arcuate and generally follows the spherical curvature of the front surface of lens 504. The nose portion 518 of the fitting 514 rests on the surface of the lens. Threaded locking systems such as bolts 520 and nuts 522 can be used to hold the mounting components in place on the lens. In a preferred embodiment, the lens may be provided with an edge notch 524 to receive the mounting component protrusion 526 to further secure the mounting component and prevent its rotation about the main axis 528 of the bolt 520. In a preferred embodiment, the main axis 528 of the fastener is located on a radial line across the center of curvature of the spherical surface of the lens.
[0133]
The preferred edge processing of the lens element of the present invention is also shown in detail in FIG. As shown, the edge surface 530 of the lens is located substantially along the radial direction 532 of the spherical surface of the lens. In the worn position, this radial direction is substantially centered on the center of rotation of the eye, PR. This edge configuration makes the lens edge essentially invisible to the wearer. This is because when the eye rotates, the edge surface is seen edge-on by the wearer, so that the gaze angle is directed at the lens edge. In addition, the edge surfaces are reduced in size to minimize appearance to an external observer. Details of this edge processing are illustrated in FIGS. 27 and 28.
[0134]
FIGS. 27A-27D illustrate some various edge profiles located approximately along the radius, R, of the spherical surface 534 of the lens. As illustrated in these figures, the cross section of the edge surface is substantially perpendicular to the tangent line T of the spherical surface at the outer peripheral portion, that is, the line of sight is substantially coplanar with the edge surface.
[0135]
In FIGS. 27A to 27D, the cross section of each edge surface is located within a small angle range θ with respect to the center of rotation P of the eye, and is therefore almost invisible to the wearer. In the example of FIG. 27A, the cross section of the edge surface is a straight line 536, and θ approaches 0. In the example of FIG. 27B, some rounding is performed to remove sharp edges that would otherwise create a security problem. In the example of FIG. 27C, a groove 538 is cut into the edge, which is adapted to mate with a portion 540 formed corresponding to the rim of the eyewear. Finally, in the example of FIG. 27D, a bead 542 is formed on the edge surface, which is adapted to mate with the grooved rim 544 of the eyewear frame. In these later cases, the edge surface is almost invisible to the wearer.
[0136]
In the examples of FIGS. 27B, 27C and 27D, θ is advantageously less than about 5 ° around the entire circumference of the lens. This situation is illustrated in FIG. 28, which is a pictorial illustration of an edged lens 546 made in accordance with a preferred embodiment of the present invention. The edge surface 548 of the lens is a ring perpendicular to the tangent of the spherical surface 550 of the lens. This ring is three-dimensional in the sense that it is not completely in one plane. The edge surface is between two generally conical shapes 552 and 554 and is at an angle θ, which may vary slightly at various locations around the lens, but is typically 3 ° ± 1.5. Less than °.
[0137]
FIGS. 29A to 29C illustrate some lens edge processing methods. FIG. 29A shows the edge machining of a conventional Ostwald section lens 560 using a conventional mill 562 rotated about an axis 564, which is held parallel to a reference axis 566 (this axis is the lens blank). Optical axis). The mill axis 564 is moved around the lens as shown by arrow 568 to form an edge surface. The use of a similar technique to edge steeply curved lens 570 is shown in FIG. 29B. As a result, the edged lens has a sharp edge 572 and a large angled edge surface in the wearer's peripheral vision.
[0138]
According to a preferred embodiment of the present invention, as illustrated in FIG. 29C, the edge surface 574 of the steeply curved lens 570 is milled about an axis 576 that is transverse to the center of curvature C of the spherical surface of the lens. 562. Previously, such an arrangement has only been used to edge non-steep, curved lenses.
[0139]
VII. Coatings, sun lenses and protective eyewear
A. coating
Lens elements having high curvature surfaces, such as those of the present invention, can be particularly difficult to coat with a film to control reflectivity / transmittance. These challenges are caused, at least in part, by the geometry of typical coating, deposition and sputtering systems. These systems can produce a relatively uniform film from the center to the edge of a relatively flat lens element. However, larger variations are observed as the surface curvature becomes steeper. The perceived color of the lens element changes with the film thickness. This color can also change throughout the lens due to changes in viewing angle. This effect is greater for steeply curved lenses. These problems are sometimes called "roll-offs."
[0140]
Techniques for coating lens elements, particularly large curved lens elements, are described in the above-cited International Application No. PCT / AU99 / 01029, entitled "Coated Lenses Showing Substantially Balanced Reflectance". Is disclosed. Various types of coatings composed of a "stack" of oxide layers are also discussed. Such a stack is illustrated generally in FIG. 30A. In this example, the steeply curved lens 600 has a spherical front surface 602 coated with a multilayer film 604 (not drawn to scale).
[0141]
An example of an anti-reflective coating that provides a generally uniform pale blue appearance from the center to the edge of the coated steeply curved lens element is an example of a stack of five layers of silicon oxide and zirconium oxide of various thicknesses Is done. The stack is shown in Table I below.
[0142]
[Table 2]

In addition to reducing roll-off, the lens is less prone to fingerprints on the lens surface and less susceptible to other systematic and non-systematic manufacturing variations. These advantages can also be achieved with conventional Ostwald section lenses.
[0143]
The foregoing technique for sputtering deposition of an oxide coating is disclosed in Burton et al., U.S. Patent Application Serial No. 09 / 605,401, filed June 28, 2000, the contents of which are incorporated herein by reference in their entirety. Incorporated in
[0144]
Figures 31 and 32 illustrate various aspects of the coatings of the present invention. FIG. 31 is a plot of reflection in percent as a function of light wavelength in nanometers. This figure compares the reflectivity of the stack of Table I with a conventional stack having a greenish color (dashed line).
[0145]
Variations in deposited film thickness of 3% or more usually cause significant and significant color changes. The green coloration is an effect of the “hump” 650 in the reflection spectrum (FIG. 31) and appears to move to the blue end of the spectrum when viewed at an oblique angle. If this happens, the reflectivity at the red end of the spectrum will be stronger. This ultimately results in pink or purple (rather than the desired yellow / green).
[0146]
In contrast, the stack of Table I (blue) produces a reflectance spectrum that shows a dominant amount of visible light reflectance in the blue portion as represented by a peak or hump 652 in the spectrum at about 480 nm. The blue coating shows a very low reflectivity into the infrared region of the spectrum, less than 0.5% at 720 nm, preferably 0.25%.
[0147]
The effect of steep lens curvature is illustrated in FIG. As can be appreciated, the reflectance of the red end of the spectrum at the center of each lens is higher for the green coating than for the blue coating. However, if the reflection is measured towards the edge of the lens, the green coating will have a large increase in reflectance in the red portion of the spectrum, while the blue coating will be stable at low red reflectance. Is clearly seen.
[0148]
The result of this increase in red reflection toward the edge of the lens is that the "green" coating turns light purple (green + red = purple). This effect does not occur to any significant degree with blue coatings. The end result of this reduced sensitivity to color roll-off is that the need for standard lens curvature grouping is greatly reduced to maintain color consistency during AR deposition. It will be apparent that steeply curved lens surfaces retain their color over the entire surface or over a greatly increased portion of the surface (as compared to more conventional coatings such as green coatings).
[0149]
B. Sun lens
It is conventional to provide sun lenses or sunglasses that selectively block the wavelengths of light in the visible and UV regions. Such lenses have both eye protection and fashion design applications. The wavelength of light passing through the lens can be selected by using light absorbing dyes in the plastic body. Alternatively or additionally, a specular coating may be applied to the lens. These techniques are applicable to the steeply curved lenses of the present invention. Further, these techniques can be used with the anti-reflective coatings described above. For example, the AR coating described above could be applied to the eye-side optical surface of a lens that contains a dye that partially blocks sunlight. Alternatively, the AR coating could be applied to the eye-side optical surface of the lens, while the front optical surface is specularly coated, for example with a bright blue reflective coating.
[0150]
C. Laser protection eyewear
The steeply curved spherical surface lens element described above may be advantageously used in laser protection eyewear. In a preferred embodiment, the eyewear is designed to place the center of curvature of each lens at the center of rotation of each eye in which the eyewear is used. In addition, the lens may be edged such that the lens extends approximately from the nasal margin of the orbit to the temporal margin and from the lower margin to the upper margin of the orbit. Alternatively, the lens may be mounted on an eyewear frame that extends to the orbital margin. These forms have several beneficial effects. First, the lens effectively surrounds the eye and can reduce or prevent stray light leakage around the edges. Second, essentially all light incident on the lens that can be transmitted through the pupil will be within about 25-30 degrees with respect to the normal to the tangent of the spherical surface. Light with a larger angle of incidence is not guided through the pupil. The laser light blocking means on or within the lens may be adjusted to block the beam of laser light within this approximately 30 ° angular range normal to the tangent of the spherical surface.
[0151]
It is known that band-blocking optical filters can be sensitive to the angle of incidence of the light to be blocked. Generally, such filters use normally incident light as the center of design. The effectiveness of a filter generally varies and usually decreases with deviation of the angle of incidence from normal. This geometry is illustrated in FIG. 30A for two arbitrary rays R1 and R2 having angles of incidence φ1 and φ2, respectively. Angles φ1 and φ2 are measured with respect to normals N1 and N2 at the points where rays R1 and R2 intersect the plane of the lens. (The perpendiculars are perpendicular to the tangent planes T1 and T2 at their respective intersections). In general, for the filters discussed above, the larger the φ, the less effective the filter effect will be.
[0152]
The steeply curved lenses of the present invention typically exhibit a smaller range of associated incident angles φ, which allows the use of filters having an effective rejection angle, for example, from normal to about 30 °. become. This aspect of a steeply curved lens is illustrated in a comparison of the two lens examples shown in FIGS. 30B and 30C. The lens 610 shown in FIG. 30B is an Ostwald section, −4D base lens. The lens 612 shown in FIG. 30C is a steeply curved lens with a -4D perspective power and a spherical surface of about 15.5D. Analysis of the incident light assumes that both lenses have a refractive index of 1.5 and a center thickness of about 2 mm. It is also envisioned that the 1 cm diameter pupil P is located 2 cm behind the point where the back of the lens intersects its optical axis OO.
[0153]
Various incident rays are plotted in FIGS. 30B and 30C. The light beam is selected from a light beam that intersects a plane PT that is in contact with each lens at the optical axis OO. The bundle is tested at distances of 0, 5, 10, 15, and 20 mm above and below the optical axis OO. From each bundle, the rays that (i) have the largest angle φ with respect to the normal to the lens at the point of incidence on the lens surface and (ii) reach the lowest point L of the pupil when refracted by the lens To be elected. These selected rays are identified by their individual distances above and below the optical axis on the plane PT (eg, 5 mm, 10 mm, etc.).
[0154]
The following table shows the calculated angles for each of the incident rays for the lenses of FIGS. 30B and 30C.
[0155]
[Table 3]

(The angle φ is expressed as both positive and negative angles. Positive angles indicate beam rotation clockwise from the lens normal as shown, negative angles indicate counterclockwise Indicates beam rotation.)
In this example, φ for the Ostwald section lens is greater than 30 ° at many locations and increases dramatically with distance from the optical axis to a height of 53.7 at the +20 mm location. Symmetrically, for the steeply curved lens of FIG. 30C, the angle φ remains less than 30 °.
[0156]
Selective blocking of laser light can be achieved with one or more optical band blocking filters. A preferred method of creating selective blocking of laser light is to use a thin film stack tuned to block potentially harmful laser light. The following is an example of a band filter that effectively blocks two laser light wavelengths frequently used in telecommunications, namely 1310 nm and 1550 nm laser light. The optical filters are described in Table III for layer configuration and thickness.
[0157]
[Table 4]

In optical design parlance, this stack is described by the following expression:
"1.12 (0.5 L H 0.5 L) 1.06 (0.5 L H 0.5 L) 1.03 (0.5 L H 0.5 L) (LHL) ∧6
1.03 (0.5 L H 0.5 L) 1.06 (0.5 L H 0.5 L) 1.12 (0.5 L H 0.5 L) "
Here, H and L indicate the quarter wavelength optical thickness of the high refractive index material and the low refractive index material at the target wavelength, respectively. In the example of Table III, the low index material is silicon dioxide and the high index material is titanium dioxide. It will be appreciated that various other stacks of conventional design can be used to provide a band blocking filter for protection from laser light.
[0158]
Continuing with the example of Table III, the optical density (the negative of the logarithm of the transmission percentage) is plotted in FIG. 33 as a function of the incident light wavelength. As can be seen from this figure, the blocked band is a broad band centered at about 1400 nm. Most visible wavelengths are passed (ie, the optical density is close to zero).
[0159]
The plot in FIG. 33 assumes an incident angle φ of 0 degree for a line N perpendicular to the tangent T of the lens surface at the point of incidence (see FIG. 30A). The optical density of the stack is expected to change as the angle of incidence φ increases from zero. The expected shifts for S and P polarization and incident light at 1310 nm and 1550 nm wavelengths are plotted in FIG.
[0160]
More specifically, in FIG. 34, the optical density is plotted as a function of the angle of incidence from 0 to 60 °. It will be appreciated that as the light incidence increases, the overall block band shifts to the left (towards blue). For this reason, the optical density increases at a wavelength of 1310 nm. As the angle of incidence φ increases, the optical density of 1550 lines decreases. For the stack of Table III, at angles less than 30 degrees, less than about 0.7% of the light is transmitted, and regardless of polarization, less than about 0.2% of light is transmitted at less than 20 degrees. This is believed to be sufficient for commercial safety applications. However, military requirements are more stringent and may require stack designs with higher optical densities in certain bands.
It will be seen from FIG. 34 that for both wavelengths and polarizations at angles of incidence up to about 33 °, the transmission of the stack remains below 1%. Larger angles of incidence will not be directed to the retina in the steeply curved lenses described herein whose center of curvature is located near the center of rotation of the protected eye. However, to insure against unwanted transmission caused by strong reflection, refraction or light leakage, the lens body may be molded from a thermoplastic containing radiation absorbing dyes.
[0161]
Thus, a new, high optical quality lens element with steep spherical curvature is provided with prescription transmission and cyl correction, and is attached to a spectacle frame adapted to use it. These designs are easily adapted for use with other protective eyewear such as very effective sunglasses and laser protective eyewear.
[0162]
The invention has been described with reference to various embodiments and examples. However, the invention to be protected is defined by the following claims and their equivalents as recognized in law.
[Brief description of the drawings]
FIG.
It is a figure of a Chernning ellipse.
FIG. 2
FIG. 1 is a cross-sectional view of a prior art high-plus power “rotoid” lens.
FIG. 3
FIG. 2 is a cross-sectional top view showing a pair of human eyes and a lens constructed in accordance with a preferred embodiment of the present invention.
FIG. 4
FIG. 3 is a Morris-Splat diagram illustrating the characteristics of a series of lens elements made in accordance with the teachings of the present invention.
FIG. 5
FIG. 4 is a diagram of a front curve and a perspective power range selected in accordance with the present invention, wherein a portion of the Chernning ellipse for this particular case is overlaid.
FIG. 6A
FIG. 3 is a schematic diagram illustrating various aspects of the geometry of a lens element of an embodiment of the present invention.
FIG. 6B
FIG. 3 is a schematic diagram illustrating various aspects of the geometry of a lens element of an embodiment of the present invention.
FIG. 6C
FIG. 3 is a schematic diagram illustrating various aspects of the geometry of a lens element of an embodiment of the present invention.
FIG. 7
FIG. 3 is a schematic diagram illustrating various aspects of the geometry of a lens element of an embodiment of the present invention.
FIG. 8
FIG. 3 is a schematic diagram illustrating various aspects of the geometry of a lens element of an embodiment of the present invention.
FIG. 9
FIG. 3 is a schematic diagram illustrating various aspects of the geometry of a lens element of an embodiment of the present invention.
FIG. 10
FIG. 4 is a diagram comparing the field of view of an example of a 6-base conventional lens and the lens and lens element of the present invention.
FIG. 11A
FIG. 11C illustrates a conventional donut toric surface astigmatism when applied to a steeply curved spherical lens having a principal meridian shown in FIG. 11C.
FIG. 11B
FIG. 11C illustrates a conventional barrel toric surface astigmatism when applied to a steeply curved spherical lens having a principal meridian shown in FIG. 11C.
FIG. 11C
It is a figure which shows the circular main meridian curvature.
FIG. 12A
12 is a graph showing tangential surface power as a function of the donut toric polar angle of FIG.
FIG. 12B
12 is a graph showing sagittal surface power as a function of the donut toric polar angle of FIG.
FIG. 12C
12 is a graph showing the tangential power as a function of the barrel toric polar angle of FIG.
FIG. 12D
12 is a graph showing sagittal surface power as a function of the polar angle of the barrel toric of FIG.
FIG. 13A
5 is a graph showing tangential surface power as a function of polar angle of the full circular meridian and average toric surface of the present invention.
FIG. 13B
5 is a graph showing sagittal plane power as a function of polar angle of the full circular meridian and average toric plane of the present invention.
FIG. 14A
5 is a graph showing tangential surface power as a function of polar angle of the full circular meridian and average toric surface of the present invention.
FIG. 14B
5 is a graph showing sagittal plane power as a function of polar angle of the full circular meridian and average toric plane of the present invention.
FIG.
FIG. 4 is a contour plot showing surface astigmatism of a lens element surface using the teachings of the present invention.
FIG.
FIG. 4 is a contour plot showing surface astigmatism of a lens element surface using the teachings of the present invention.
FIG. 17A
It is a figure which shows an object grid and its image.
FIG. 17B
It is a figure which shows an object grid and its image.
FIG. 17C
It is a figure which shows an object grid and its image.
FIG.
FIG. 4 is a side sectional view showing a mold used for manufacturing a lens element according to an embodiment of the present invention.
FIG.
FIG. 4 is a plot showing the calculated RMS power error and distortion and ray tracing grid for three conventional low base lenses and three steeply curved lens elements according to the present invention.
FIG.
FIG. 4 is a plot showing the calculated RMS power error, distortion and ray tracing grid for a steeply curved lens with a conventional toric back and a full circular meridian back.
FIG. 21
FIG. 3 is a contour plot comparing a conventional 6D base progressive lens with a 16D base progressive lens according to the present invention.
FIG.
FIG. 3 is a contour plot comparing a conventional 6D base progressive lens with a 16D base progressive lens according to the present invention.
FIG. 23
FIG. 3 illustrates various aspects of the lens element of the present invention and the appearance, edge processing and glazing of an eyeglass frame for use therewith.
FIG. 24
FIG. 3 illustrates various aspects of the lens element of the present invention and the appearance, edge processing and glazing of an eyeglass frame for use therewith.
FIG. 25A
FIG. 3 illustrates various aspects of the lens element of the present invention and the appearance, edge processing and glazing of an eyeglass frame for use therewith.
FIG. 25B
FIG. 3 illustrates various aspects of the lens element of the present invention and the appearance, edge processing and glazing of an eyeglass frame for use therewith.
FIG. 26
(A) is a plan view of an embodiment of the eyewear of the present invention, and (b) is a detailed view of the embodiment of FIG. 26 (a) showing a mounting part, a hinge, and a lens structure with edge processing.
FIG. 27A
FIG. 4 is an illustration of various lens edge surfaces used in a preferred embodiment of the present invention.
FIG. 27B
FIG. 4 is an illustration of various lens edge surfaces used in a preferred embodiment of the present invention.
FIG. 27C
FIG. 4 is an illustration of various lens edge surfaces used in a preferred embodiment of the present invention.
FIG. 27D
FIG. 4 is an illustration of various lens edge surfaces used in a preferred embodiment of the present invention.
FIG. 28
FIG. 3 is a pictorial diagram of the edged lens of the present invention, illustrating the thickness of the edge.
FIG. 29A
It is an illustration of some lens edge processing methods.
FIG. 29B
It is an illustration of some lens edge processing methods.
FIG. 29C
It is an illustration of some lens edge processing methods.
FIG. 30A
FIG. 3 is a cross-sectional view of various lens elements, with the incident light beam impinging on the surface of the lens.
FIG. 30B
FIG. 3 is a cross-sectional view of various lens elements, with the incident light beam impinging on the surface of the lens.
FIG. 30C
FIG. 3 is a cross-sectional view of various lens elements, with the incident light beam impinging on the surface of the lens.
FIG. 31
FIG. 4 is a plot of reflection versus incident light wavelength for various coatings, illustrating aspects of the invention.
FIG. 32
FIG. 4 is a plot of reflection versus incident light wavelength for various coatings, illustrating aspects of the invention.
FIG. 33
FIG. 4 is a plot of optical density for an example of a band block filter according to a preferred embodiment of the present invention.
FIG. 34
FIG. 4 is a plot of optical density for an example of a band block filter according to a preferred embodiment of the present invention.

Claims (44)

A lens adapted for mounting on eyewear, the lens having a spherical surface having a radius of curvature of less than about 35 mm, wherein the lens is positioned such that the center of curvature of the lens is substantially at the center of rotation of the eye. A lens large enough to provide a field of view greater than 55 ° in a temporal direction from a frontal line of sight, and further having an anti-reflective coating that presents the viewer with a substantially uniform color over its entire surface. The lens of claim 1, wherein the surface is at least one spherical surface and has a radius of curvature of 33.25 mm ± 1 mm. The lens of claim 1, wherein the lens has an anti-reflective coating on both the surface and the eye-side optical surface. The lens of claim 1, wherein the lens has a non-zero prescription transmission power. The lens according to claim 4, wherein the lens has an eye surface for correcting astigmatism of a wearer. The lens of claim 1, wherein the anti-reflection coating is a dielectric stack applied to at least one optical surface of the lens, which appears generally blue. The lens of claim 1, wherein the coating comprises a layer having a relatively high refractive index and a relatively low refractive index vacuum deposited on at least one optical surface of the lens. The lens of claim 7, wherein the surface coating is a stack of silicon and zirconium oxide layers, wherein at least one zirconium oxide layer has a thickness greater than about 100 nm. The lens of claim 7, wherein the reflectance of the visible light coating has a local maximum at about 480nm. An edged sun lens having a first optical surface located within a spherical shell defined by two concentric spheres having radii that differ by no more than 2 mm, wherein the smaller of said radii is A lens having a length of less than or equal to 50 mm and wherein at least two points O and Q on the edge of the surface form an angle OPQ greater than 80 ° with respect to the center P of the shell. The lens of claim 10, wherein the first optical surface has a radius of curvature of 33.25 ± 1 mm. The lens according to claim 10, wherein the first optical surface has a surface power of 15.5D to 16.5D. 13. The lens of claim 12, wherein the first optical surface is a front lens surface, and the back surface of the lens is configured such that the lens has a power selected from + 2D to -5.75D. lens. The lens of claim 10, wherein the back surface of the lens is configured such that the lens has a selected astigmatism correction of up to 2.5D. The lens according to claim 10, wherein the angle OPQ is greater than 90 °. The lens according to claim 10, wherein the lens is made from a lens blank having an angle OPQ greater than 120 °. The lens of claim 10, wherein the lens is attached to eyewear such that a center of curvature of a front surface is positioned at about a center of rotation of a wearer's eye in a wearing position. The lens of claim 10, wherein the lens presents a substantially uniform color to an observer over its entire surface. The lens of claim 10 wherein the surface is coated with a dielectric stack whose reflectivity begins to decrease for incident light at wavelengths above about 380 nm and remains low throughout the rest of the visible spectrum. . Protective eyewear,
Left and right lenses, each having a spherical surface, each spherical surface having a radius of curvature of about 31 mm to 35 mm,
Means for supporting the lens on the wearer's face so that the center of each spherical surface of the left and right lenses is approximately positioned at the center of rotation of the left and right eyes,
Eyewear associated with each lens to at least partially block radiation incident on the lenses from being transmitted to the respective eye. The transmission blocking means is a multilayer film on each lens, each layer of the film having a different refractive index and thickness selected to at least partially block at least one selected portion of the spectrum of the incident radiation. The eyewear according to claim 20, comprising: 22. The eyewear of claim 21, wherein the eyewear is sunglasses, and wherein ultraviolet light is at least partially blocked. 22. Eyewear according to claim 21, wherein the laser radiation in the selected spectral range is at least partially blocked. 24. Eyewear according to claim 23, wherein the infrared laser radiation is at least partially blocked. 24. The method of claim 23, wherein the incident laser radiation is in a band that includes at least one telecommunications laser light wavelength that is blocked enough to reduce its power level to an eye-safe level. Eyewear. In order to block laser radiation coming from all angles incident on the pupil, each lens with supporting means extends from the nasal margin of the orbital region to the temporal margin of the orbital region and from the lower margin of the orbital region to the upper margin. The eyewear according to claim 23, characterized in that: Each lens extends from the nasal margin of the orbital region to the temporal margin of the orbital region and from the lower margin of the orbital region to the upper margin to block laser radiation coming from all angles incident on the pupil. 24. The eyewear of claim 23. The support means includes left and right temporal components and a nose bridge, and each lens is large enough to provide a temporal field of view greater than 55 ° in a temporal direction from a forward line of sight of each eye. Item 21. The eyewear according to item 20. The transmission blocking means is a filter whose blocking characteristics are affected by the angle of incidence of light rays incident on the lens,
In the wearing position, the rays reaching the pupil of the wearer's eye deviate by no more than 30 ° from the normal to the surface of the respective lens at the point of incidence,
21. The filter of claim 20, wherein the filter is effective to reduce the power level of the incident light beam to a safe level over an entire angle of incidence of at least 30 degrees from a normal to the lens surface at the point of incidence. Eyewear Eyewear,
Left and right lenses each having at least one spherical surface having a radius of curvature of about 31 mm to 35 mm;
An eyewear frame including left and right temporal parts and a nose bridge for supporting the lens on the wearer's face so that the centers of the spherical surfaces of the left and right lenses are approximately positioned at the center of rotation of the left and right eyes. And
Eyewear wherein each lens is edge-processed such that an edge surface of the lens is substantially perpendicular to a tangent of the spherical surface. The eyewear of claim 30, wherein the eyewear frame is rimless. The frame may further include left and right temporal attachment parts attached to the left and right lenses by fasteners, respectively, and a main axis of the fastener is oriented on a line passing through a center of curvature of a substantially spherical surface. Item 32. The eyewear according to Item 31. 31. The eyewear of claim 30, wherein the spherical surface of each lens is the front surface of each lens. 31. The eyewear of claim 30, wherein the edge surface of each lens intersects the spherical surface of the lens along a line located substantially outside any single plane. The eyewear of claim 30, wherein the edge surface is created by a mill rotated about an axis that intersects a center of curvature of the spherical surface. The eyewear of claim 35, wherein the mill cuts a grooved edge surface adapted to mate with a rim of an eyewear frame. The eyewear of claim 35, wherein the mill leaves a bead on the edge surface adapted to mate with a grooved rim of an eyewear frame. 36. The eyewear of claim 35, wherein any sharp edges left by the mill are removed by beveling. The edge of at least one lens is substantially thicker than the center of the lens, and the edge surface of the lens has an arc ほ ぼ of approximately 5 ° or less, and a spherical surface in which the arc lies in any plane including the optical axis of the lens 31. Eyewear according to claim 30, wherein the eyewear is cut so as to be stretched about the center of curvature of the surface. A method of manufacturing a steeply curved lens element having a non-zero prescription transmission rate, adapted to be attached to eyewear, comprising:
Molding a lens blank having a radius of curvature of less than 35 mm along a principal meridian over a substantial portion of the surface;
Cutting into the molded lens blank a back surface that provides a non-zero prescription transmission with the front surface;
Edge milling the lens blank to provide an edge milled lens having a maximum hollow depth of at least 8 mm. 41. The method of claim 40, wherein the cut back surface, together with the front surface, provides the wearer with non-zero astigmatism correction. 42. The method of claim 41, wherein a circular meridian toroid is used in generating the back surface to provide astigmatism correction to the wearer. 41. The method of claim 40, wherein the progressive power addition is provided by at least a surface of the lens element. 41. The method of claim 40, wherein the progressive power addition is provided by at least a back surface of the lens element.

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