JP4806157B2 - Low fluorescent optical glass - Google Patents
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- JP4806157B2 JP4806157B2 JP2002519336A JP2002519336A JP4806157B2 JP 4806157 B2 JP4806157 B2 JP 4806157B2 JP 2002519336 A JP2002519336 A JP 2002519336A JP 2002519336 A JP2002519336 A JP 2002519336A JP 4806157 B2 JP4806157 B2 JP 4806157B2
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C3/00—Glass compositions
- C03C3/04—Glass compositions containing silica
- C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
- C03C3/097—Glass compositions containing silica with 40% to 90% silica, by weight containing phosphorus, niobium or tantalum
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C3/00—Glass compositions
- C03C3/04—Glass compositions containing silica
- C03C3/062—Glass compositions containing silica with less than 40% silica by weight
Description
技術分野
本発明は、屈折率（ｎｄ）が１．６８〜１．７８、アッベ数（νｄ）が２７〜３５であり、紫外線励起による蛍光度（けい光度）が小さい低蛍光性光学ガラスに関する。
背景技術
生物学や医療等の分野において、生物の組織や細胞、細菌等を観察するために、紫外線等の励起光を観察対象に照射して、観察対象から発せられる蛍光を観察および測定する手法が多く用いられており、近年は、非常に少量の細菌や細胞等から発せられる微弱な蛍光を検出する技術が盛んに研究されている。
ところが、このような観察や測定に用いられる蛍光顕微鏡の対物レンズ等に使われている光学ガラスからも、紫外線励起によって蛍光が発生し、この蛍光が観察対象から発せられる蛍光を観察する際のノイズとなるため、紫外線励起によって発生する蛍光の強さ（日本光学硝子工業会規格では、けい光度として示される）が小さい光学ガラスが望まれている。
高度に収差補正された蛍光顕微鏡の対物レンズ等の光学系は、種々の屈折率、分散を持つ光学ガラスにより構成されるが、従来の光学ガラス、特に、高分散光学ガラスには、紫外線励起によるけい光度（蛍光度）が小さくなるように考慮されたものがほとんどなく、前述したように、ノイズの問題があるため、蛍光度の大きい従来の高分散光学ガラスを、紫外線領域の励起光を観察対象に照射して、観察対象から発生する微弱な蛍光を観察したり測定したりする蛍光顕微鏡の光学機器の光学系に用いることはできない。
以上の理由から、近年、高分散の低蛍光光学ガラスがいくつか提案されている。例えば特開平１０−１５８０２９号公報には、Ｂ２Ｏ３−Ｐ２Ｏ５−Ｒ１ ２Ｏ−Ｎｂ２Ｏ５および／またはＴａ２Ｏ５系組成の高分散の低蛍光光学ガラスが開示されているが、このガラスは、化学的耐久性が十分ではないという欠点がある。
また、特開平１０−２３１１４０号公報には、組成がＢ２Ｏ３−Ｐ２Ｏ５−Ｒ１ ２Ｏ−Ｔａ２Ｏ５系である高分散の低蛍光光学ガラスが開示されているが、このガラスは、化学的耐久性および光線透過性が十分でないうえ、原料費が非常に高価なＴａ２Ｏ５成分を大量に導入しているため、製造コストが高いという問題も有している。
また、特開平１０−３１６４４９号公報には、Ｇｅ２Ｏ３−Ｔａ２Ｏ５−Ｒ１ ２Ｏ系組成の高分散の低蛍光光学ガラスが開示されているが、このガラスも化学耐久性が十分ではなく、Ｔａ２Ｏ５成分を大量に含有していることに加えて、やはり、原料費が非常に高価なＧｅ２Ｏ３成分も大量に含有しているため、製造コストが非常に高く実用的ではない。
光学ガラスは、その光線透過性が優れていることが要求されることはもちろんであるが、光学ガラスを研削または研磨する工程や、レンズ等を洗浄する工程では、ガラス表面のヤケ等の発生を防止するために、ガラスの化学的耐久性が優れていることが求められる。また、製造コストを低減するために、光学ガラスを構成する諸成分の原料費は、なるべく安価であることが望まれる。ところが、前述したように、従来の高分散の低蛍光光学ガラスは、これらの諸要求に十分応えるものとは言い難い。本発明の目的は、上記従来技術の諸問題を総合的に解決し、屈折率（ｎｄ）が１．６８〜１．７８、アッベ数（νｄ）が２７〜３５という高屈折率高分散性を有し、紫外線励起による蛍光度が小さく、かつ、優れた化学的耐久性および光線透過性を有し、しかも、比較的低い原料コストで製造することができる低蛍光性光学ガラスを提供することにある。
発明の開示
本発明者は、鋭意試験研究を重ねた結果、従来、具体的に開示されていない特定組成範囲のＳｉＯ２−ＺｒＯ２−Ｎｂ２Ｏ５−Ｒ２Ｏ（Ｒは、Ｌｉ、ＮａおよびＫから選ばれる１種または２種以上）系ガラスにおいて、前記所望範囲の光学定数（屈折率（ｎｄ）およびアッベ数（νｄ））を有し、紫外線励起による蛍光度が小さく、かつ、優れた化学的耐久性および光線透過性を有するガラスが得られることを見出し、本発明をなすに至った。
すなわち、本発明にかかる第一の態様の低蛍光性光学ガラスは、酸化物基準の質量％で、
ＳｉＯ２ ３０〜４５％、
ＺｒＯ２ ０．５〜１０％、
Ｎｂ２Ｏ５ ３０〜５０％、
Ｔａ２Ｏ５ ０〜１５％、
Ｌｉ２Ｏ ０〜１２％未満、
Ｎａ２Ｏ ０〜１２％未満、
Ｋ２Ｏ ０〜１２％未満、
ただし、Ｌｉ２Ｏ＋Ｎａ２Ｏ＋Ｋ２Ｏ １〜１２％未満、
ＭｇＯ ０〜４％、
ＣａＯ ０〜４％、
ＳｒＯ ０〜４％、
ＢａＯ ０〜４％、
ＺｎＯ ０〜４％、
ただし、ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ＋ＺｎＯ ０〜４％、
Ｓｂ２Ｏ３ ０〜１％、
Ａｓ２Ｏ３ ０〜１％
の範囲の各成分を含有し、Ｂ２Ｏ３を含有しないことを特徴とする。
また、本発明にかかる第二の態様の低蛍光性光学ガラスは、酸化物基準の質量％で、
ＳｉＯ２ ３０〜４５％、
ＺｒＯ２ ０．５〜１０％、
Ｎｂ２Ｏ５ ３０〜５０％、
Ｔａ２Ｏ５ ０〜１５％、
ただし、Ｎｂ２Ｏ５＋Ｔａ２Ｏ５が５５％以下、
Ｌｉ２Ｏ ０〜１２％未満、
Ｎａ２Ｏ ０〜１２％未満、
Ｋ２Ｏ ０〜１２％未満、
ただし、Ｌｉ２Ｏ＋Ｎａ２Ｏ＋Ｋ２Ｏ ７〜１２％未満、
かつ、質量比で、ＳｉＯ２／（Ｌｉ２Ｏ＋Ｎａ２Ｏ＋Ｋ２Ｏ）が３．３以上、
Ｓｂ２Ｏ３ ０〜１％、
Ａｓ２Ｏ３ ０〜１％
の範囲の各成分を含有し、Ｂ２Ｏ３を含有しないことを特徴とする。
また、好ましくは、本発明にかかる第一および第二の態様の低蛍光性光学ガラスにおいて、酸化物基準の質量％で、Ｔａ２Ｏ５の含有量が０．５〜１１％未満である。
また、好ましくは、本発明にかかる第一および第二の態様の低蛍光性光学ガラスは、屈折率（ｎｄ）が１．６８〜１．７８、アッベ数（νｄ）が２７〜３５の範囲の光学定数を有する。
また、好ましくは、本発明にかかる第一および第二の態様の低蛍光性光学ガラスにおいて、国際標準化機構ＩＳＯ８４２４：１９９６（Ｅ）の測定方法により測定するガラスの耐酸性（ＳＲ）の級が級１である。
また、好ましくは、本発明の第一および第二の態様の低蛍光性光学ガラスは、日本光学硝子工業会規格「光学ガラスのけい光度の測定方法」（ＪＯＧＩＳ０３−１９７５）に基づき測定するガラスのけい光度が級１である。
発明を実施するための最良の形態
本発明の低蛍光性光学ガラスにおいて、各成分の組成範囲を前記のとおり限定した理由を以下に述べる。
すなわち、ＳｉＯ２成分は、ガラス形成酸化物であるとともに、ガラスの失透に対する安定性および化学的耐久性を向上させる成分であり、失透に対する安定性および化学的耐久性を維持するためには、３０％以上必要である。また、その量が４５％を超えると、かえって、失透して、得られるガラスが乳白色となりやすくなる。
ＺｒＯ２成分は、ガラスの屈折率を高めるとともに、その化学的耐久性を向上させ、かつ、ガラスの失透傾向を抑制するのに有効な成分であるが、その量が０．５％未満では上記効果が十分でなく、また１０％を超えるとかえってガラスの失透傾向が強くなる。
Ｎｂ２Ｏ５成分は、本発明において、所望範囲の光学定数を維持しつつ、紫外線励起による蛍光度を大幅に小さくする効果がある重要な成分であるが、その量が２０％未満では上記効果が得られず、５０％を超えると光線透過性が悪化する。
また、Ｎｂ２Ｏ５成分は、後述するＴａ２Ｏ５成分ほどではないが、原料コストが比較的高い成分であり、Ｔａ２Ｏ５成分を添加する場合、ガラスの製造コストを低く抑えるために、Ｎｂ２Ｏ５およびＴａ２Ｏ５成分の合計量を５５％以下とすることが、より好ましい。
Ｔａ２Ｏ５成分は、ガラスに含有させることによって、所望範囲の光学定数を維持しつつ、光線透過性および化学的耐久性を向上させる効果があるため任意に添加しうるが、その量が１５％を超えると、ガラスの溶融性が著しく悪化し、Ｔａ２Ｏ５成分の溶け残りが生じやすい。
また、上記効果を十分に発揮させるためには、Ｔａ２Ｏ５成分の含有量を０．５％以上とすることがより好ましい。また、Ｔａ２Ｏ５成分は、本発明のガラスの諸成分の中で、特に、原料費が高い成分であり、上記効果を得つつ、ガラスの製造コストを低く抑え、かつ、ガラスの溶融性をさらに向上させて、均質なガラスを得やすくするためには、その量を１１％未満とすることが、より好ましい。
Ｌｉ２Ｏ、Ｎａ２ＯおよびＫ２Ｏの各成分は、いずれも、ガラスの溶融を促進する効果があるが、これらの成分の１種または２種以上の合計量が１％未満では上記効果が十分に得られず、また合計量が１２％を超えると、所望の高屈折率高分散性を得にくくなり、蛍光度も大きくなりやすい。
また、ガラスの溶融性を特に良くするためには、これらの成分の１種または２種以上の合計量を７％以上とすることが、より好ましい。また、白金または白金合金製の坩堝や清澄槽等を用いてガラスを溶融または清澄する場合、上記溶融促進効果を得つつ、白金イオンのガラスへの溶け込みを少なくして、光線透過性が特に優れたガラスを得るために、質量比で、ＳｉＯ２／（Ｌｉ２Ｏ＋Ｎａ２Ｏ＋Ｋ２Ｏ）を３．３以上にすることが、より好ましい。
ＢａＯ、ＣａＯ、ＭｇＯ、ＳｒＯおよびＺｎＯ成分は、いずれも、光学定数の調整、ガラスの溶融性および耐失透性を改善する目的で、必要に応じて添加し得るが、これら５成分の１種または２種以上の合計量が４％を超えると光線透過性が著しく悪化する。
Ｓｂ２Ｏ３およびＡｓ２Ｏ３成分は、それぞれ、ガラス溶融の際の清澄剤として任意に添加しうるが、清澄の効果を得るためには、１％までで十分であり、特に、光線透過性に優れ、かつ、小さい蛍光度を有するガラスを得るためには、これらの成分の量を、それぞれ、０．５％までとすることがより好ましく、それぞれ、０．３％までとすることがさらに好ましく、これらの成分の量が、それぞれ、０．３％以下でも溶解条件を調整することで十分、清澄可能である。
なお、上記以外の成分、例えば、Ｆ（弗素）成分を、光線透過性の向上を目的として、４％まで、ガラスの溶融性および耐失透性を改善する目的で、必要に応じて本発明のガラスに添加してもよい。
実施例
本発明の低蛍光性光学ガラスにかかる好適な実施例（Ｎｏ．１〜Ｎｏ．１４）の組成および従来の光学ガラスの比較例（Ｎｏ．ＡおよびＮｏ．Ｂ）の組成を、これらのガラスの屈折率（ｎｄ）、アッベ数（νｄ）、反射損失を含む分光透過率８０％を示す光線の波長（Ｔ８０；単位ｎｍ）、けい光度（蛍光度）の測定結果および耐酸性のクラス（ＳＲ）とともに表１〜表３に示した。ここで、Ｔ８０は対面研磨した厚さ１０ｍｍのガラス試料について測定した結果を示したものである。また、けい光度の測定は、日本光学硝子工業会規格「光学ガラスのけい光度の測定方法」（ＪＯＧＩＳ０３−１９７５）に基づいて行ない、標準試料として、日本光学硝子工業会指定のフリントガラスを用いて、実施例および比較例のガラス試料ならびに上記標準試料に、主波長が３６５ｎｍの紫外線を照射して生じた蛍光（けい光）の強さを測定した。けい光度は、けい光の強さの測定値から、標準試料に対する各ガラス試料のけい光の強さの比を求め、比が１．５以上の場合を級３、０．７以上から１．５未満の場合を級２、０．７未満の場合を級１として示すものである。けい光度が級１のガラスであれば、紫外線励起による蛍光の強さは十分に小さく、蛍光顕微鏡の対物レンズ等に用いることができる。
また、耐酸性を示すクラス（ＳＲ）は、国際標準化機構ＩＳＯ８４２４：１９９６（Ｅ）の測定方法により、測定して得た結果を示したものである。ここで、ＳＲは、６面を研磨した３０×３０×２ｍｍのガラス試料が、所定の酸処理液中で、０．１μｍの侵食を受けるのに要した時間（ｈ）によって等級付けしたものであり、ＳＲが１、２、３および４の場合は、ｐＨ０．３の硝酸溶液を用いて、それぞれ、侵食に、１００を超えるｈ、１００ｈ〜１０ｈ、１０ｈ未満から１ｈまで、および１ｈ未満から０．１ｈまでを要したことを示す。したがって、ＳＲのクラスの値が小さいほどガラスの耐酸性が高く、化学的耐久性が優れていることを示す。
また、表４に示す耐酸性のクラス（ＳＲ）は、表１〜表３に示す耐酸性のクラス（ＳＲ）を上記ＩＳＯ８４２４：１９９６（Ｅ）の測定方法により、さらに細別したもので、上記酸処理直後のガラス試料の表面を観察し、酸処理によって生じた研磨面の変化を下記のとおり分類したものであり、例えば、ＳＲが級１．０の場合、侵食に、１００を超えるｈを要し、かつ、酸処理直後、研磨面に変化がないことを示す。
．０ 変化なし
．１ きれい、だが不規則な表面（波うち、へこみ）
．２ 干渉色（僅かな選択的溶出）
．３ 固着した白い層（より強い選択的溶出）
．４ 崩れやすい沈着物（表面クラスト）
また、本発明の実施例のガラス（Ｎｏ．１〜Ｎｏ．１４）は、いずれも、耐酸性（ＳＲ）が級１であり、ＳＲが級２である比較例Ｎｏ．Ｂの従来の高分散低蛍光光学ガラスよりも、耐酸性が優れ、化学的耐久性が優れていることが分かる。
さらに、表４に見られるとおり、本発明の実施例のガラス（Ｎｏ．７、Ｎｏ．９およびＮｏ．１３）は細別した耐酸性（ＳＲ）の級が１．０であり、耐酸性（ＳＲ）の級が２．４である比較例Ｎｏ．Ｂの従来の高分散低蛍光光学ガラスよりも、耐酸性が格段に優れていることが分かる。
また、本発明の実施例のガラス（Ｎｏ，１〜Ｎｏ．１４）は、反射損失を含む分光透過率８０％を示す光線の波長（Ｔ８０）が、３６５〜３９７ｎｍの範囲にあり、比較例Ｎｏ．ＡおよびＮｏ．Ｂの従来の光学ガラスと比べて、反射損失を含む分光透過率８０％を示す光線の波長（Ｔ８０）がほぼ同等もしくは、より短波長側にシフトしており、可視域の短波長側から近紫外域における光線透過性に優れていることが分かる。
なお、表１〜表３に組成を示した本発明の実施例のガラス（Ｎｏ．１〜Ｎｏ．１４）は、いずれも、酸化物、炭酸塩、硝酸塩、水酸化物等の通常の光学ガラス用原料を所定の割合となるように秤量し、混合した後、白金坩堝等に投入し、組成による溶融性に応じて１１００〜１３５０℃の温度で約２〜４時間溶融し、攪拌均質化した後、金型等に鋳込み徐冷することにより容易に得ることができた。産業上の利用可能性
以上述べたとおり、本発明の低蛍光性光学ガラスは、特定組成範囲のＳｉＯ２−ＺｒＯ２−Ｎｂ２Ｏ５−Ｒ２Ｏ（Ｒは、Ｌｉ、ＮａおよびＫから選ばれる１種または２種以上）系のガラスであるから、屈折率（ｎｄ）が１．６８〜１．７８、アッベ数（νｄ）が２７〜３５の範囲の光学定数を有し、高屈折率および高分散性を示し、紫外線励起による蛍光度が小さく、低蛍光性を有しているうえ、化学的耐久性および光線透過性に優れている。したがって、特に、蛍光顕微鏡等の光学系の対物レンズ等として用いるのに好適であり、蛍光測定用溶液セルや固体撮像素子のカバーガラス等の低蛍光性が要求されるガラス部材として用いるのにも適している。また、通常の光学ガラスとして、カメラ、デジタルカメラ、ビデオカメラ等の各種光学機器の光学系のレンズ等として用いるのにも適しており有用である。また、原料費が高価な成分を大量に含有していないため、製造コストの点でも従来の高分散性低蛍光光学ガラスよりも有利である。TECHNICAL FIELD The present invention relates to a low-fluorescence optical glass having a refractive index (nd) of 1.68 to 1.78, an Abbe number (νd) of 27 to 35, and low fluorescence (fluorescence) due to ultraviolet excitation.
Background Art In the fields of biology and medicine, in order to observe biological tissues, cells, bacteria, etc., a method of observing and measuring fluorescence emitted from an observation target by irradiating the observation target with excitation light such as ultraviolet rays In recent years, techniques for detecting weak fluorescence emitted from a very small amount of bacteria or cells have been actively studied.
However, the optical glass used in the objective lens of a fluorescence microscope used for such observation and measurement also generates fluorescence by ultraviolet excitation, and this fluorescence is noise when observing the fluorescence emitted from the observation target. Therefore, there is a demand for an optical glass having a low intensity of fluorescence generated by ultraviolet excitation (shown as fluorescence in the Japan Optical Glass Industry Association standard).
Optical systems such as objective lenses of fluorescent microscopes that have been highly aberration corrected are composed of optical glasses having various refractive indexes and dispersions. However, conventional optical glasses, particularly high dispersion optical glasses, are produced by ultraviolet excitation. There is almost no consideration to reduce the fluorescence (fluorescence), and as mentioned above, there is a problem of noise, so conventional high-dispersion optical glass with high fluorescence is observed in the excitation light in the ultraviolet region. It cannot be used in an optical system of an optical device of a fluorescence microscope that irradiates an object and observes or measures weak fluorescence generated from the observation object.
For these reasons, several high-dispersion low fluorescence optical glasses have been proposed in recent years. For example, Japanese Patent Laid-Open No. 10-158029, B 2 O 3 -P 2 O 5 -R 1 2 O-Nb 2 O 5 and / or low-fluorescence optical glass having a high dispersion characteristic of Ta 2 O 5 based composition is disclosed However, this glass has a drawback that its chemical durability is not sufficient.
JP-A-10-231140, but the composition is low fluorescent optical glass of high dispersion is disclosed a B 2 O 3 -P 2 O 5 -R 1 2 O-Ta 2 O 5 system, This glass has a problem that the production cost is high because chemical durability and light transmittance are not sufficient, and a large amount of Ta 2 O 5 component having a very high raw material cost is introduced.
JP-A-10-316449, although a low fluorescent optical glass of Ge 2 O 3 -Ta 2 O 5 -R 1 2 high dispersion of O-based composition is disclosed, the glass also chemical durability In addition to containing a large amount of the Ta 2 O 5 component, the production cost is very high because it also contains a large amount of the Ge 2 O 3 component, which is very expensive in raw material costs. Not practical.
Of course, optical glass is required to have excellent light transmittance, but in the process of grinding or polishing the optical glass and the process of cleaning the lens, the occurrence of burns on the glass surface is caused. In order to prevent this, the chemical durability of the glass is required to be excellent. Moreover, in order to reduce manufacturing cost, it is desired that the raw material costs of the various components constituting the optical glass be as low as possible. However, as described above, the conventional high-dispersion low-fluorescence optical glass cannot be said to sufficiently meet these various requirements. The object of the present invention is to comprehensively solve the above-mentioned problems of the prior art, and to achieve a high refractive index and high dispersibility with a refractive index (nd) of 1.68 to 1.78 and an Abbe number (νd) of 27 to 35. The present invention provides a low-fluorescence optical glass that has low fluorescence due to ultraviolet excitation, has excellent chemical durability and light transmittance, and can be manufactured at a relatively low raw material cost. is there.
Disclosed our invention is a result of intensive research, the prior art, SiO 2 -ZrO 2 -Nb 2 O 5 -R 2 O (R having a specific composition range that is not specifically disclosed, Li, Na And one or more selected from K) glass having an optical constant in the desired range (refractive index (nd) and Abbe number (νd)), low fluorescence due to ultraviolet excitation, and excellent In addition, the inventors have found that a glass having chemical durability and light transmittance can be obtained, and have made the present invention.
That is, the low-fluorescence optical glass of the first aspect according to the present invention is in mass% based on oxide,
SiO 2 30~45%,
ZrO 2 0.5-10%,
Nb 2 O 5 30-50%,
Ta 2 O 5 0-15%,
Li 2 O 0 to less than 12%,
Na 2 O 0-12%,
K 2 O 0-12%,
However, Li 2 O + Na 2 O + K 2 O less than 1 to 12%,
MgO 0-4%,
CaO 0-4%,
SrO 0-4%,
BaO 0-4%,
ZnO 0-4%,
However, MgO + CaO + SrO + BaO + ZnO 0-4%,
Sb 2 O 3 0 to 1%,
As 2 O 3 0-1%
Contain each ingredient in the range of, characterized in that it does not contain B 2 O 3.
The low-fluorescence optical glass according to the second aspect of the present invention is an oxide-based mass%,
SiO 2 30~45%,
ZrO 2 0.5-10%,
Nb 2 O 5 30-50%,
Ta 2 O 5 0-15%,
However, Nb 2 O 5 + Ta 2 O 5 is 55% or less,
Li 2 O 0 to less than 12%,
Na 2 O 0-12%,
K 2 O 0-12%,
However, Li 2 O + Na 2 O + K 2 O 7 to less than 12%,
And, by mass ratio, SiO 2 / (Li 2 O + Na 2 O + K 2 O) is 3.3 or more,
Sb 2 O 3 0 to 1%,
As 2 O 3 0-1%
Contain each ingredient in the range of, characterized in that it does not contain B 2 O 3.
Preferably, in the low-fluorescence optical glass of the first and second embodiments according to the present invention, the content of Ta 2 O 5 is 0.5 to less than 11% by mass% based on oxide.
Preferably, the low fluorescence optical glass of the first and second embodiments according to the present invention has a refractive index (nd) of 1.68 to 1.78 and an Abbe number (νd) of 27 to 35. It has an optical constant.
Preferably, in the low-fluorescence optical glass of the first and second aspects according to the present invention, the acid resistance (SR) class of the glass measured by the measurement method of International Standardization Organization ISO 8424: 1996 (E) 1.
Preferably, the low-fluorescence optical glass of the first and second aspects of the present invention is a glass that is measured based on the Japan Optical Glass Industry Association Standard “Measurement Method of Fluorescence of Optical Glass” ( JOGIS03-1975 ). The fluorescence intensity is class 1.
BEST MODE FOR CARRYING OUT THE INVENTION The reason for limiting the composition range of each component as described above in the low-fluorescence optical glass of the present invention will be described below.
That is, the SiO 2 component is a glass-forming oxide and is a component that improves the stability and chemical durability against devitrification of the glass. In order to maintain the stability and chemical durability against devitrification 30% or more is necessary. On the other hand, if the amount exceeds 45%, the glass is devitrified and the resulting glass tends to be milky white.
The ZrO 2 component is an effective component for increasing the refractive index of the glass, improving its chemical durability, and suppressing the devitrification tendency of the glass. However, if the amount is less than 0.5%, The above effect is not sufficient, and if it exceeds 10%, the tendency of glass to devitrify becomes stronger.
In the present invention, the Nb 2 O 5 component is an important component that has the effect of significantly reducing the fluorescence due to ultraviolet excitation while maintaining the optical constant in the desired range. However, when the amount is less than 20%, the above effect is achieved. Is not obtained, and if it exceeds 50%, the light transmittance deteriorates.
Further, the Nb 2 O 5 component is not as high as the Ta 2 O 5 component described later, but is a component with a relatively high raw material cost, and when adding the Ta 2 O 5 component, in order to keep the glass manufacturing cost low. More preferably, the total amount of Nb 2 O 5 and Ta 2 O 5 components is 55% or less.
The Ta 2 O 5 component can be optionally added because it has the effect of improving the light transmittance and chemical durability while maintaining the optical constant in the desired range by being contained in the glass. If it exceeds 50%, the meltability of the glass is remarkably deteriorated, and the undissolved portion of the Ta 2 O 5 component tends to be generated.
In order to sufficiently exhibit the above effect, the content of Ta 2 O 5 component is more preferably 0.5% or more. The Ta 2 O 5 component is a component having a particularly high raw material cost among the various components of the glass of the present invention. While obtaining the above effect, the production cost of the glass is kept low, and the melting property of the glass. In order to further improve the above and make it easier to obtain a homogeneous glass, it is more preferable to make the amount less than 11%.
Each component of Li 2 O, Na 2 O and K 2 O has an effect of promoting melting of the glass, but the above effect is obtained when the total amount of one or more of these components is less than 1%. When the total amount exceeds 12%, it is difficult to obtain the desired high refractive index and high dispersibility, and the fluorescence tends to increase.
In order to improve the meltability of the glass, the total amount of one or more of these components is more preferably 7% or more. In addition, when melting or clarifying glass using a crucible or fining tank made of platinum or a platinum alloy, the melting acceleration effect is obtained, and the penetration of platinum ions into the glass is reduced, and the light transmittance is particularly excellent. In order to obtain a thick glass, it is more preferable that SiO 2 / (Li 2 O + Na 2 O + K 2 O) is 3.3 or more by mass ratio.
Any of BaO, CaO, MgO, SrO and ZnO components can be added as necessary for the purpose of adjusting optical constants, improving the meltability and devitrification resistance of glass. Alternatively, when the total amount of two or more types exceeds 4%, the light transmittance is remarkably deteriorated.
Each of the Sb 2 O 3 and As 2 O 3 components can be optionally added as a fining agent during glass melting, but up to 1% is sufficient to obtain a fining effect, and in particular, light transmission In order to obtain a glass having excellent properties and low fluorescence, it is more preferable that the amount of each of these components is 0.5% or less, and each is 0.3% or less. More preferably, even if the amount of these components is 0.3% or less, they can be clarified sufficiently by adjusting the dissolution conditions.
It should be noted that components other than those described above, for example, an F (fluorine) component, are used as necessary for the purpose of improving the light transmittance and improving the melting property and devitrification resistance of glass up to 4%. It may be added to the glass.
Examples The compositions of preferred examples (No. 1 to No. 14) and the compositions of comparative examples (No. A and No. B) of conventional optical glasses according to the low-fluorescence optical glass of the present invention are as follows. Glass refractive index (nd), Abbe number (νd), wavelength of light ray showing 80% spectral transmittance including reflection loss (T 80 ; unit nm), measurement result of fluorescence (fluorescence) and acid resistance class It was shown in Tables 1 to 3 together with (SR). Here, T 80 shows the results of measurement for the glass sample having a thickness of 10mm which faces polished. In addition, measurement of silicon luminosity, carried out on the basis of the Japan Optical Glass Industry Association standard "method of measuring the Kei intensity of optical glass" (JOGIS03- 1975), as a standard sample, using a flint glass of Japan Optical Glass Industry Association specified The intensity of fluorescence (fluorescence) generated by irradiating the glass samples of Examples and Comparative Examples and the standard sample with ultraviolet light having a dominant wavelength of 365 nm was measured. For the fluorescence intensity, the ratio of the fluorescence intensity of each glass sample to the standard sample is obtained from the measured value of the fluorescence intensity. The case of less than 5 is shown as class 2, and the case of less than 0.7 is shown as class 1. If the glass has a fluorescence level of Class 1, the intensity of fluorescence due to ultraviolet excitation is sufficiently small, and can be used for an objective lens of a fluorescence microscope.
The class (SR) indicating acid resistance indicates the result obtained by measurement by the measurement method of International Standardization Organization ISO 8424: 1996 (E). Here, SR is graded according to the time (h) required for a 30 × 30 × 2 mm glass sample polished on six surfaces to undergo erosion of 0.1 μm in a predetermined acid treatment solution. Yes, when SR is 1, 2, 3 and 4, nitric acid solution with pH 0.3 is used to attack more than 100 h, 100 h to 10 h, less than 10 h to 1 h, and less than 1 h to 0 It shows that it took up to 1h. Therefore, the smaller the SR class value, the higher the acid resistance of the glass and the better the chemical durability.
Further, the acid resistance class (SR) shown in Table 4 is obtained by further subdividing the acid resistance class (SR) shown in Tables 1 to 3 by the measurement method of ISO 8424: 1996 (E). The surface of the glass sample immediately after the treatment is observed, and changes in the polished surface caused by the acid treatment are classified as follows. For example, when SR is grade 1.0, erosion requires more than 100 h. And it shows that there is no change in the polished surface immediately after the acid treatment.
. 0 No change. 1 Clean, but irregular surface (waves, dents)
. 2 Interference color (slight selective elution)
. 3 Solid white layer (stronger selective elution)
. 4 Deposits that tend to collapse (surface crust)
Moreover, as for the glass (No.1-No.14) of the Example of this invention, all are comparative example No. whose acid resistance (SR) is grade 1 and SR is grade 2. It can be seen that the acid resistance and chemical durability are superior to those of the conventional high-dispersion low-fluorescence optical glass of B.
Furthermore, as can be seen in Table 4, the glass (No. 7, No. 9, and No. 13) of the examples of the present invention has a subdivided acid resistance (SR) grade of 1.0, and the acid resistance (SR ) Grade of 2.4 is Comparative Example No. It can be seen that the acid resistance is remarkably superior to the conventional high dispersion low fluorescence optical glass of B.
The glass embodiment of the present invention (No, 1~No.14), the wavelength of the light that shows 80% spectral transmittance including reflection loss (T 80) is in the range of 365～397Nm, Comparative Example No. A and No. Compared with the conventional optical glass of B, the wavelength (T 80 ) of the light beam showing the spectral transmittance of 80% including the reflection loss is almost equal or shifted to the shorter wavelength side, and from the shorter wavelength side in the visible range. It turns out that it is excellent in the light transmittance in a near ultraviolet region.
In addition, as for the glass (No.1-No.14) of the Example of this invention which showed the composition in Table 1-Table 3, all are normal optical glasses, such as an oxide, carbonate, nitrate, a hydroxide. The raw materials were weighed and mixed so as to have a predetermined ratio, then charged into a platinum crucible, etc., melted at a temperature of 1100 to 1350 ° C. for about 2 to 4 hours according to the meltability according to the composition, and stirred and homogenized. Thereafter, it could be easily obtained by casting into a mold or the like and gradually cooling. As described above INDUSTRIAL APPLICABILITY, low fluorescence optical glass of the present invention, SiO 2 -ZrO 2 -Nb 2 O 5 -R 2 O (R a specific composition range, selected from Li, Na and K 1 type or two or more types) glass having a refractive index (nd) of 1.68 to 1.78, an Abbe number (νd) of 27 to 35, and a high refractive index. In addition, it exhibits high dispersibility, low fluorescence due to ultraviolet excitation, low fluorescence, and excellent chemical durability and light transmittance. Therefore, it is particularly suitable for use as an objective lens of an optical system such as a fluorescence microscope, and also as a glass member requiring low fluorescence such as a solution cell for fluorescence measurement or a cover glass of a solid-state imaging device. Is suitable. Moreover, it is suitable and useful as a lens of an optical system of various optical devices such as a camera, a digital camera, and a video camera as a normal optical glass. In addition, since the raw material does not contain a large amount of expensive components, it is more advantageous than the conventional high-dispersion low-fluorescence optical glass in terms of manufacturing cost.
Claims (6)
ＳｉＯ２ ３０〜４５％、
ＺｒＯ２ ０．５〜１０％、
Ｎｂ２Ｏ５ ３０〜５０％、
Ｔａ２Ｏ５ ０〜１５％、
Ｌｉ２Ｏ ０〜１２％未満、
Ｎａ２Ｏ ０〜１２％未満、
Ｋ２Ｏ ０〜１２％未満、
ただし、Ｌｉ２Ｏ＋Ｎａ２Ｏ＋Ｋ２Ｏ １〜１２％未満、
ＭｇＯ ０〜４％、
ＣａＯ ０〜４％、
ＳｒＯ ０〜４％、
ＢａＯ ０〜４％、
ＺｎＯ ０〜４％、
ただし、ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ＋ＺｎＯ ０〜４％、
Ｓｂ２Ｏ３ ０〜１％、
Ａｓ２Ｏ３ ０〜１％
の範囲の各成分を含有し、Ｂ２Ｏ３を含有しないことを特徴とする低蛍光性光学ガラス。% By mass based on oxide,
SiO 2 30~45%,
ZrO 2 0.5-10%,
Nb 2 O 5 30-50%,
Ta 2 O 5 0-15%,
Li 2 O 0 to less than 12%,
Na 2 O 0-12%,
K 2 O 0-12%,
However, Li 2 O + Na 2 O + K 2 O less than 1 to 12%,
MgO 0-4%,
CaO 0-4%,
SrO 0-4%,
BaO 0-4%,
ZnO 0-4%,
However, MgO + CaO + SrO + BaO + ZnO 0-4%,
Sb 2 O 3 0 to 1%,
As 2 O 3 0-1%
A low-fluorescence optical glass characterized by containing each component in the above range and not containing B 2 O 3 .
ＳｉＯ２ ３０〜４５％、
ＺｒＯ２ ０．５〜１０％、
Ｎｂ２Ｏ５ ３０〜５０％、
Ｔａ２Ｏ５ ０〜１５％、
ただし、Ｎｂ２Ｏ５＋Ｔａ２Ｏ５が５５％以下、
ＭｇＯ ０〜４％、
ＣａＯ ０〜４％、
ＳｒＯ ０〜４％、
ＢａＯ ０〜４％、
ＺｎＯ ０〜４％、
ただし、ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ＋ＺｎＯ ０〜４％、
Ｌｉ２Ｏ ０〜１２％未満、
Ｎａ２Ｏ ０〜１２％未満、
Ｋ２Ｏ ０〜１２％未満、
ただし、Ｌｉ２Ｏ＋Ｎａ２Ｏ＋Ｋ２Ｏ ７〜１２％未満、
かつ、質量比で、ＳｉＯ２／（Ｌｉ２Ｏ＋Ｎａ２Ｏ＋Ｋ２Ｏ）が３．３以上、
Ｓｂ２Ｏ３ ０〜１％、
Ａｓ２Ｏ３ ０〜１％
の範囲の各成分を含有し、Ｂ２Ｏ３を含有しないことを特徴とする低蛍光性光学ガラス。% By mass based on oxide,
SiO 2 30~45%,
ZrO 2 0.5-10%,
Nb 2 O 5 30-50%,
Ta 2 O 5 0-15%,
However, Nb 2 O 5 + Ta 2 O 5 is 55% or less,
MgO 0-4%,
CaO 0-4%,
SrO 0-4%,
BaO 0-4%,
ZnO 0-4%,
However, MgO + CaO + SrO + BaO + ZnO 0-4%,
Li 2 O 0 to less than 12%,
Na 2 O 0-12%,
K 2 O 0-12%,
However, Li 2 O + Na 2 O + K 2 O 7 to less than 12%,
And, by mass ratio, SiO 2 / (Li 2 O + Na 2 O + K 2 O) is 3.3 or more,
Sb 2 O 3 0 to 1%,
As 2 O 3 0-1%
A low-fluorescence optical glass characterized by containing each component in the above range and not containing B 2 O 3 .
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|---|---|---|---|
| JP2002519336A JP4806157B2 (en) | 2000-08-15 | 2001-08-09 | Low fluorescent optical glass |
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| JP2000246490 | 2000-08-15 | ||
| JP2000246490 | 2000-08-15 | ||
| PCT/JP2001/006850 WO2002014235A1 (en) | 2000-08-15 | 2001-08-09 | Low fluorescent optical glass |
| JP2002519336A JP4806157B2 (en) | 2000-08-15 | 2001-08-09 | Low fluorescent optical glass |
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| WO2022062637A1 (en) * | 2020-09-28 | 2022-03-31 | 成都光明光电股份有限公司 | Optical glass |
| WO2022062638A1 (en) * | 2020-09-28 | 2022-03-31 | 成都光明光电股份有限公司 | Optical glass, optical element, and optical device |
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| JP2008280235A (en) | 2007-04-09 | 2008-11-20 | Olympus Corp | Optical glass and optical device using the same |
| JP5545917B2 (en) | 2008-01-31 | 2014-07-09 | 株式会社オハラ | Optical glass |
| CN104926110B (en) * | 2015-06-23 | 2019-04-16 | 成都光明光电股份有限公司 | Optical glass and optical element |
| JP6932423B2 (en) | 2015-11-06 | 2021-09-08 | 株式会社オハラ | Optical glass, preforms and optics |
| US10370289B2 (en) * | 2015-11-11 | 2019-08-06 | Ohara Inc. | Optical glass, preform, and optical element |
| WO2017090645A1 (en) * | 2015-11-24 | 2017-06-01 | 旭硝子株式会社 | Optical glass |
| JP7133901B2 (en) * | 2016-02-29 | 2022-09-09 | 株式会社オハラ | Optical glass, preforms and optical elements |
| JP7272757B2 (en) * | 2018-05-31 | 2023-05-12 | Hoya株式会社 | Optical glasses and optical elements |
| JP7433830B2 (en) | 2019-10-02 | 2024-02-20 | 光ガラス株式会社 | Optical glass, optical element using optical glass, optical system, interchangeable lens, optical device, and method for manufacturing optical glass |
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| JPS6212635A (en) * | 1985-07-09 | 1987-01-21 | Hoya Corp | Glass composition suitable of producing glass material having refractive index gradient |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022062637A1 (en) * | 2020-09-28 | 2022-03-31 | 成都光明光电股份有限公司 | Optical glass |
| WO2022062638A1 (en) * | 2020-09-28 | 2022-03-31 | 成都光明光电股份有限公司 | Optical glass, optical element, and optical device |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2002014235A1 (en) | 2002-02-21 |
| AU2001277729A1 (en) | 2002-02-25 |
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