JP3791946B2 - High dispersion optical glass - Google Patents
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- JP3791946B2 JP3791946B2 JP24881295A JP24881295A JP3791946B2 JP 3791946 B2 JP3791946 B2 JP 3791946B2 JP 24881295 A JP24881295 A JP 24881295A JP 24881295 A JP24881295 A JP 24881295A JP 3791946 B2 JP3791946 B2 JP 3791946B2
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Description
【０００１】
【発明の属する技術分野】
本発明は、屈折率（ｎｄ）が１．５８〜１．８２、アッベ数（νｄ）が２０〜４０の範囲の光学恒数を有し、かつ、ＰｂＯ成分を含まない特定組成域のＳｉＯ2−Ｎｂ2Ｏ5−Ｂｉ2Ｏ3−Ｒ’2Ｏ（ただし、Ｒ’はＬｉ、Ｎａ、Ｋを示す。）系の高分散光学ガラスに関する。
【０００２】
【従来の技術】
従来、前記の光学恒数を有するガラスとしては、ＳｉＯ2−ＰｂＯ−Ｒ’2Ｏ系が知られているが、このガラスはＰｂＯ成分を含有しており、かつ、黄色に着色し易いうえにガラスの比重が高くなるため使用上不利である。特開昭５２−２５８１２号公報には、ＳｉＯ2−ＴｉＯ2−Ｎｂ2Ｏ5−Ｒ’2Ｏ系のガラスが開示されているが、このガラスは、本発明の目標とする高分散特性および耐失透性の双方を十分に満足するものとは言い難い。
【０００３】
さらに、特開平５−２６２５３４号公報には、ＳｉＯ2−Ｎｂ2Ｏ5−Ｒ’2Ｏ−Ｆ系の高分散性光学ガラスが開示されているが、このガラスは、Ｆ（弗素）の揮発による組成変動から脈理や失透が発生しやすく、品質劣化を招きやすい。
【０００４】
【発明が解決しようとする課題】
本発明は、前記従来のガラスにみられる諸欠点を総合的に改善し、屈折率（ｎｄ）１．５８〜１．８２、アッベ数（νｄ）２０〜４０の範囲の光学恒数を有し、かつ、耐失透性を改善した高分散光学ガラスを提供することを目的にしている。
【０００５】
【課題を解決するための手段】
本発明者は、前記の目的を達成するため鋭意試験研究を重ねた結果、従来には具体的に開示されていない特定組成範囲のＳｉＯ2−Ｎｂ2Ｏ5−Ｂｉ2Ｏ3−Ｒ’2Ｏ系のガラスにおいて、所望の光学恒数を有し、かつ、一段と耐失透性を改善したガラスが得られることを見いだし本発明をなすに至った。
【０００６】
前記目的を達成する本発明にかかる高分散光学ガラスの組成の特徴は、特許請求の範囲に記載のとおり、重量％で、
ＳｉＯ2 ２０〜４６％、
Ｂ2Ｏ3 ０〜 ７％、
Ａｌ2Ｏ3 ０〜 ５％、
Ｎｂ2Ｏ5 ２０〜５５％、
ＴｉＯ2 ０〜１４％、
ＷＯ3 ０〜１５％、
Ｂｉ2Ｏ3 ０．５〜２０％、
ＲＯ（ただし、ＲはＭｇ、Ｃａ、Ｓｒ、Ｂａを示す。） ０〜１０％、
Ｒ’2Ｏ（ただし、Ｒ’はＬｉ、Ｎａ、Ｋを示す。） １０〜３０％、を含有し、Ｐ 2 Ｏ 5 を含有しないことにある。
【０００７】
上記のとおり各成分の組成範囲を限定した理由は、次のとおりである。
すなわち、ＳｉＯ2成分は、ガラスを形成させる必須の成分であるが、その量が２０％未満であるとガラスの化学的耐久性が低下し、また、４６％を超えるとガラスの溶融性が悪化するので２０〜４６％の範囲にすべきである。
Ｂ2Ｏ3成分は、ガラスの溶融性向上のため化学的耐久性を悪化しない範囲内の７％まで添加し得る。
【０００８】
Ａｌ2Ｏ3成分は、光学恒数の調整およびガラスの安定性向上のため適宜添加し得るが、その量が５％を超えると溶融性が悪化し均質なガラスが得難くなる。
Ｎｂ2Ｏ5成分は、後述のＢｉ2Ｏ3成分と共にガラスに含有させることによって高い光線透過性を維持しつつ高分散能を高める効果がある重要な成分であるが、その量が２０％未満では目標の光学恒数が得られず、また、５５％を超えるとガラスの失透傾向が大きくなるので、２０〜５５％の範囲にすべきである。
【０００９】
ＴｉＯ2成分は、ガラスの屈折率を高め、アッベ数を小さくするのに有効であるので適宜添加し得るが、その量が１４％を超えるとガラスの着色が増大する。
ＷＯ3成分は、ガラスの屈折率を高め、失透傾向を抑制する効果があるので添加し得るが、その量が１５％を超えるとかえって失透しやすくなる。
Ｂｉ2Ｏ3成分は、屈折率を高め、また、上記Ｎｂ2Ｏ5成分と共に含有させることによって高分散能を著しく高める効果があるが、０．５％未満ではその効果が十分ではなく、また、２０％を超えるとガラスの耐失透性および光線透過性が悪化するので、より好ましい範囲は０．５〜１５％とすべきである。
【００１０】
ＲＯ成分、すなわちＭｇＯ、ＣａＯ、ＳｒＯ、およびＢａＯの各成分は、ガラスの溶融性改善に効果があるので任意に添加し得るが、これらの成分の１種または２種以上の合計量が１０％を超えると目標の光学恒数を維持し難くなる。
Ｒ’2Ｏ成分、すなわちＬｉ2Ｏ、Ｎａ2Ｏ、およびＫ2Ｏの各成分は、いずれもガラスの溶融性を促進する効果があるので任意に添加し得るが、これらの成分の合計量が１０％未満ではその効果が不十分であり、また３０％を超えると耐失透性が悪化する。なお、本発明のガラスには、上記成分の他に公知の脱泡剤であるＡｓ2Ｏ3およびＳｂ2Ｏ3を１％程度まで含有させることができる。
【００１１】
【発明の実施の形態】
つぎに、本発明にかかる高分散光学ガラスの好適な実施組成例（Ｎｏ．１〜Ｎｏ．７）および従来の光学ガラスの比較組成例（Ｎｏ．ＡおよびＮｏ．Ｂ）をこれらのガラスの屈折率（ｎｄ）、アッベ数（νｄ）および失透試験結果と共に表１に示した。
【００１２】
【表１】
表記のガラスは、いずれも通常の光学ガラス原料を用いて調合、混合し、白金坩堝を用い、約１２００〜１４００℃、約２〜５時間で溶融脱泡し、攪拌均質化した後、ブロック形状に成形し徐冷して得た。なお、表１における失透試験結果は、白金製５０ｃｃポットにガラス試料８０ｇを入れて電気炉内で各ガラスの溶融性の難易度に応じて１１００〜１３００℃の温度で２時間溶融した後、降温して各試料を１０５０℃、１０００℃で２時間保温した後、炉外に取り出して失透の有無を顕微鏡により観察したもので、その結果、失透が認められないガラスは○印で、また、失透が認められたガラスは×印で示した。
【００１４】
表１に見られるとおり、本発明の実施例はいずれも従来公知の比較例ガラスと比較して耐失透性に優れており、目的の改善効果は顕著である。
【００１５】
なお、前記実施例のガラスＮｏ．４およびＮｏ．５は記載していないが、転移温度が５５０℃以下であるため、モールドプレス用素材としても適している。
【００１６】
【発明の効果】
上述のとおり、本発明の高分散光学ガラスは、特定範囲量のＳｉＯ2−Ｎｂ2Ｏ5−Ｂｉ2Ｏ3−Ｒ’2Ｏ系組成の高分散光学ガラスであるから、屈折率（ｎｄ）が１．５８〜１．８２、アッベ数（νｄ）が２０〜４０の光学恒数を有すると共に、従来のガラスに比べて耐失透性に優れており、また、モールドプレス用ガラスにも適しているので有用である。[0001]
BACKGROUND OF THE INVENTION
The present invention has a specific composition range of SiO 2 having an optical constant having a refractive index (nd) of 1.58 to 1.82 and an Abbe number (νd) of 20 to 40 and not including a PbO component. -Nb 2 O 5 -Bi 2 O 3 -R '2 O ( provided that, R' is Li, Na, shows a K.) relates to a high dispersion optical glass system.
[0002]
[Prior art]
Conventionally, SiO 2 —PbO—R ′ 2 O system is known as the glass having the optical constant, but this glass contains a PbO component and is easily colored yellow. Since the specific gravity of glass becomes high, it is disadvantageous in use. Japanese Patent Application Laid-Open No. 52-25812 discloses SiO 2 —TiO 2 —Nb 2 O 5 —R ′ 2 O glass, which has the high dispersion characteristics and the target of the present invention. It is hard to say that both of the devitrification resistance are sufficiently satisfied.
[0003]
Furthermore, Japanese Patent Application Laid-Open No. 5-262534 discloses a SiO 2 —Nb 2 O 5 —R ′ 2 O—F-based highly dispersible optical glass. This glass is a volatilization of F (fluorine). The striae and devitrification are likely to occur due to the composition variation due to the above, and the quality is likely to deteriorate.
[0004]
[Problems to be solved by the invention]
The present invention comprehensively improves various disadvantages found in the conventional glass and has optical constants in the range of refractive index (nd) 1.58 to 1.82 and Abbe number (νd) 20 to 40. And it aims at providing the high dispersion optical glass which improved devitrification resistance.
[0005]
[Means for Solving the Problems]
As a result of intensive studies and studies to achieve the above object, the present inventor has found that SiO 2 —Nb 2 O 5 —Bi 2 O 3 —R ′ 2 having a specific composition range that has not been specifically disclosed so far. It has been found that an O-based glass having a desired optical constant and having further improved resistance to devitrification can be obtained.
[0006]
The characteristics of the composition of the high-dispersion optical glass according to the present invention that achieves the above object are, as described in the claims, expressed in weight%
SiO 2 20~46%,
B 2 O 3 0-7%,
Al 2 O 3 0-5%,
Nb 2 O 5 20-55%,
TiO 2 0-14%,
WO 3 0~15%,
Bi 2 O 3 0.5-20%,
RO (where R represents Mg, Ca, Sr, Ba) 0 to 10%,
R ′ 2 O (where R ′ represents Li, Na, K), 10 to 30%, and does not contain P 2 O 5 .
[0007]
The reason for limiting the composition range of each component as described above is as follows.
That is, the SiO 2 component is an essential component for forming glass, but if its amount is less than 20%, the chemical durability of the glass is lowered, and if it exceeds 46%, the meltability of the glass is deteriorated. Therefore, it should be in the range of 20 to 46%.
The B 2 O 3 component may be added up to 7% within a range that does not deteriorate the chemical durability for improving the meltability of the glass.
[0008]
The Al 2 O 3 component can be appropriately added to adjust the optical constant and improve the stability of the glass. However, if the amount exceeds 5%, the meltability deteriorates and it becomes difficult to obtain a homogeneous glass.
The Nb 2 O 5 component is an important component that has the effect of enhancing the high dispersibility while maintaining high light transmittance by being contained in the glass together with the Bi 2 O 3 component described later, but its amount is less than 20%. In this case, the target optical constant cannot be obtained, and if it exceeds 55%, the glass tends to devitrify. Therefore, it should be in the range of 20 to 55%.
[0009]
The TiO 2 component is effective in increasing the refractive index of the glass and reducing the Abbe number and can be added as appropriate. However, if the amount exceeds 14%, the coloring of the glass increases.
The WO 3 component can be added because it has the effect of increasing the refractive index of the glass and suppressing the tendency to devitrification. However, if the amount exceeds 15%, it tends to be devitrified.
The Bi 2 O 3 component has an effect of increasing the refractive index and remarkably increasing the high dispersibility by containing it together with the Nb 2 O 5 component. However, if it is less than 0.5%, the effect is not sufficient. More than 20%, the devitrification resistance and light transmittance of the glass deteriorate, so a more preferable range should be 0.5 to 15%.
[0010]
RO components, that is, MgO, CaO, SrO, and BaO are effective in improving the meltability of the glass and can be optionally added. However, the total amount of one or more of these components is 10%. If it exceeds, it becomes difficult to maintain the target optical constant.
The R ′ 2 O component, that is, each of Li 2 O, Na 2 O, and K 2 O has an effect of promoting the melting property of the glass and can be arbitrarily added. However, the total amount of these components If it is less than 10%, the effect is insufficient, and if it exceeds 30%, devitrification resistance deteriorates. The glass of the present invention can contain up to about 1% of As 2 O 3 and Sb 2 O 3 which are known defoamers in addition to the above components.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, preferred examples of composition (No. 1 to No. 7) of the high dispersion optical glass according to the present invention and comparative composition examples (No. A and No. B) of the conventional optical glass are refracted by these glasses. Table 1 shows the ratio (nd), Abbe number (νd), and devitrification test results.
[0012]
[Table 1]
All the indicated glasses are prepared and mixed using ordinary optical glass raw materials, melted and defoamed at about 1200 to 1400 ° C. for about 2 to 5 hours using a platinum crucible, and stirred and homogenized, and then block shape And then cooled and obtained. The results of the devitrification test in Table 1 are as follows. After putting a glass sample 80 g in a platinum 50 cc pot and melting it at a temperature of 1100 to 1300 ° C. for 2 hours in an electric furnace according to the difficulty of melting of each glass, After the temperature was lowered and each sample was kept at 1050 ° C. and 1000 ° C. for 2 hours, it was taken out of the furnace and observed with a microscope for the presence or absence of devitrification. Moreover, the glass in which devitrification was recognized was shown by x mark.
[0014]
As can be seen in Table 1, all of the examples of the present invention are superior in devitrification resistance as compared with conventionally known comparative glass, and the intended improvement effect is remarkable.
[0015]
In addition, glass No. of the said Example. 4 and no. Although 5 is not described, since the transition temperature is 550 ° C. or lower, it is also suitable as a material for mold press.
[0016]
【The invention's effect】
As described above, since the high-dispersion optical glass of the present invention is a high-dispersion optical glass having a specific range of SiO 2 —Nb 2 O 5 —Bi 2 O 3 —R ′ 2 O-based composition, the refractive index (nd). Has an optical constant of 1.58 to 1.82 and Abbe number (νd) of 20 to 40, and is superior in devitrification resistance compared to conventional glass, and is also suitable for glass for mold presses. It is so useful.
Claims (1)
ＳｉＯ2 ２０〜４６％、
Ｂ2Ｏ3 ０〜 ７％、
Ａｌ2Ｏ3 ０〜 ５％、
Ｎｂ2Ｏ5 ２０〜５５％、
ＴｉＯ2 ０〜１４％、
ＷＯ3 ０〜１５％、
Ｂｉ2Ｏ3 ０．５〜２０％、
ＲＯ（ただし、ＲはＭｇ、Ｃａ、Ｓｒ、Ｂａを示す。） ０〜１０％、
Ｒ’2Ｏ（ただし、Ｒ’はＬｉ、Ｎａ、Ｋを示す。） １０〜３０％、の範囲の各成分を含有し、Ｐ 2 Ｏ 5 を含有しないことを特徴とする高分散光学ガラス。% By weight
SiO 2 20~46%,
B 2 O 3 0-7%,
Al 2 O 3 0-5%,
Nb 2 O 5 20-55%,
TiO 2 0-14%,
WO 3 0~15%,
Bi 2 O 3 0.5-20%,
RO (where R represents Mg, Ca, Sr, Ba) 0 to 10%,
R ′ 2 O (where R ′ represents Li, Na, K) 10% to 30% of each component is contained , and P 2 O 5 is not contained .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24881295A JP3791946B2 (en) | 1995-09-01 | 1995-09-01 | High dispersion optical glass |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24881295A JP3791946B2 (en) | 1995-09-01 | 1995-09-01 | High dispersion optical glass |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0971435A JPH0971435A (en) | 1997-03-18 |
| JP3791946B2 true JP3791946B2 (en) | 2006-06-28 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24881295A Expired - Fee Related JP3791946B2 (en) | 1995-09-01 | 1995-09-01 | High dispersion optical glass |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3791946B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6413894B1 (en) * | 1998-04-30 | 2002-07-02 | Hoya Corporation | Optical glass and optical product |
| JP2010105902A (en) * | 2008-09-30 | 2010-05-13 | Ohara Inc | Optical glass and method for suppressing deterioration of spectral transmittance |
| JP7195040B2 (en) * | 2015-12-07 | 2022-12-23 | 株式会社オハラ | Optical glass, preforms and optical elements |
| CN109987838B (en) * | 2019-04-24 | 2022-04-15 | 成都光明光电股份有限公司 | Optical glass, glass preform, optical element and optical instrument |
-
1995
- 1995-09-01 JP JP24881295A patent/JP3791946B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0971435A (en) | 1997-03-18 |
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