CN105731788A - Glass, glass material for compression moulding, optical element blank and optical element - Google Patents

Abstract

The invention provides a glass which contains rare earth oxides and has excellent thermal stability, high refraction and low chromatic dispersion. In the glass composition with oxides as references, the mass ratio between the content of SiO2 and the total contents of B2O3, SiO2 and P2O5 is 0.050 to 0.250, the mass ratio between the content of Gd2O3 and the total contents of La2O3, Gd2O3, Y2O3, Yb2O3 and Lu2O3 is less than 0.360, the mass ratio between the total contents of the B2O3, SiO2 and P2O5 and the total contents of the La2O3, Gd2O3, Y2O3, Yb2O3, Lu2O3 and ZrO2 ranges from 0.405 to 0.460 inclusive, the mass ratio between the content of the Ta2O5 and the total contents of La2O3, Gd2O3, Y2O3, Yb2O3, Lu2O3 and ZrO2 is less than 0.030, the mass ratio between the total contents of Nb2O5, TiO2, WO3 and Bi2O3 and the total contents of La2O3, Gd2O3, Y2O3, Yb2O3, Lu2O3 and ZrO2 is less than 0.013, the content of Gd2O3 surpasses 8.0 weight %, the content of La2O3 is 38-48 weight %, the content of Nb2O5 is less than 1.0 weight %, a refraction rate nd has a range between 1.78 and 1.80, and the abbe number vd has a range between 47 and 50.

Description

Glass, compressing glass material, optical element blank and optical element

Technical field

The present invention relates to a kind of glass, compressing glass material, optical element blank and optical element.

Background technology

As high-refractivity and low-dispersion glass, it is known to comprise the glass (with reference to patent documentation 1～11) of rare-earth oxide.

High-refractivity and low-dispersion glass is as the optical element material of various lens etc., and its demand is high.This is because, the lens of high-refractivity and low-dispersion such as can consist of the optical system of chromatic aberration correction compact, H.D the lens combination with high index of refraction high dispersivity.And then, by by the optical function face aspherisation of the lens of high-refractivity and low-dispersion such that it is able to seek the further multifunction of various optical system, densification.

Prior art literature

Patent documentation

Patent documentation 1: Japanese Laid-Open Patent Publication 61-219738 publication；

Patent documentation 2: Japanese Unexamined Patent Publication 2010-248057 publication；

Patent documentation 3: Japanese Unexamined Patent Publication 2010-265164 publication；

Patent documentation 4: Japanese Unexamined Patent Publication 2007-269584 publication；

Patent documentation 5: Japanese Unexamined Patent Publication 2009-242210 publication；

Patent documentation 6: Japanese Unexamined Patent Publication 2012-46410 publication；

Patent documentation 7: Japanese Unexamined Patent Publication 2013-107810 publication；

Patent documentation 8: Japanese Laid-Open Patent Publication 58-069741 publication；

Patent documentation 9: Japanese Unexamined Patent Publication 2005-239544 publication；

Patent documentation 10: Japanese Laid-Open Patent Publication 56-160340 publication；

Patent documentation 11: Japanese Laid-Open Patent Publication 59-169952 publication.

, as the method for the optical elements such as making lens, it is known to following method, i.e. make the intermediate products being referred to as optical element blank that the shape with optical element is approximate, the enforcement grinding of these intermediate products, polishing are manufactured optical element.As a mode of the manufacture method of such intermediate products, have the appropriate compressing method for intermediate products of melten glass (being called straight pressing).Additionally, as other mode, have following method: melten glass is cast in mold and is shaped to glass plate, cut off this glass plate and make multiple sheet glass, by this sheet glass reheat, softening and by the compressing method making intermediate products；Appropriate melten glass is shaped to the glass blocks being referred to as glass gob, this glass blocks is reheated, softening, be pressed and the method that obtains intermediate products, etc..Relative to straight pressing, method glass reheating, softening being pressed is referred to as reheating pressing.

Additionally, as the method making optical element, it is also known that there is following method, namely, make compressing glass material with melten glass, utilize shaping mould that this compressing glass material is carried out precision press molding, thus obtain optical element (being called precision press molding method).In precision press molding method, by the forming surface shape of transfer printing molded mould such that it is able to form the optical function face of optical element when without machinings such as grinding, polishings.

The straight pressing recorded above, reheat pressing, precision press molding method any one in, if precipitating out crystal in the fabrication process in glass, be just difficult to the optical element obtaining that there is the outstanding transparency.It is therefore desirable to inhibit the glass that the crystal in manufacture process precipitates out, i.e. the glass that heat stability is high.

On the other hand, in glass ingredient, rare-earth oxide because can improve refractive index (when Abbe number is not greatly reduced) when dispersion is not greatly improved and as the making useful composition of high-refractivity and low-dispersion glass.Therefore, the glass described in patent documentation 1～11 all comprises La₂O₃、Gd₂O₃Deng more than one of rare-earth oxide.But, the research according to the present inventor, the glass comprising rare-earth oxide generally has the tendency lacking heat stability.

Summary of the invention

The problem that invention to solve

Therefore, the purpose of a mode of the present invention is in that, it is provided that a kind of comprise rare-earth oxide and the outstanding high-refractivity and low-dispersion glass of heat stability.

One mode of the present invention relates to a kind of glass, wherein,

In the glass composition being benchmark with oxide,

Nb₂O₅、TiO₂、WO₃And Bi₂O₃Total content relative to La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃、Lu₂O₃And ZrO₂Add up to content mass ratio [(Nb₂O₅+TiO₂+WO₃+Bi₂O₃)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] less than 0.013,

Ta₂O₅Content relative to La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃、Lu₂O₃And ZrO₂Add up to content mass ratio [Ta₂O₅/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] less than 0.030,

B₂O₃、SiO₂And P₂O₅Total content relative to La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃、Lu₂O₃And ZrO₂Add up to content mass ratio [(B₂O₃+SiO₂+P₂O₅)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] it is more than 0.405 and less than 0.460,

SiO₂Content relative to B₂O₃、SiO₂And P₂O₅Add up to content mass ratio [SiO₂/(B₂O₃+SiO₂+P₂O₅)] it is 0.050～0.250,

Gd₂O₃Content relative to La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃And Lu₂O₃Add up to content mass ratio [Gd₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃)] less than 0.360,

Gd₂O₃Content more than 8.0 mass %,

La₂O₃Content be 38～48 mass %,

Nb₂O₅Content less than 1.0 mass %,

Refractive index nd ranges for 1.78～1.80, and Abbe number ν d range for 47～50.

Above-mentioned glass is to comprise rare-earth oxide Gd with above-mentioned content respectively₂O₃And La₂O₃And there is the refractive index of above-mentioned scope and the high-refractivity and low-dispersion glass of Abbe number, in this glass, by making the ratio of the content/total content of above-mentioned various composition in above-mentioned scope such that it is able to illustrate outstanding heat stability.

Invention effect

A mode according to the present invention, using the teaching of the invention it is possible to provide a kind of comprise rare-earth oxide, illustrate high-refractivity and low-dispersion characteristic and can show which the glass of outstanding heat stability.A mode according to the present invention, using the teaching of the invention it is possible to provide a kind of compressing glass material, optical element blank and optical element being made up of above-mentioned glass.

Detailed description of the invention

[glass]

The glass of one mode of the present invention be have above-mentioned glass composition, refractive index nd range for 1.78～1.80 and Abbe number ν d range for 47～50 glass.Hereinafter, above-mentioned glass is described in detail.

It addition, below unless otherwise specified, refractive index refers to the refractive index nd of the d line (wavelength is 587.56nm) of helium.

Additionally, Abbe number ν d uses as the value representing the character relevant to dispersion, it is set to represent with following formula.At this, nF is the refractive index of the blue F line (wavelength is 486.13nm) of hydrogen, and nC is the refractive index of the red C line (wavelength is 656.27nm) of hydrogen.

ν d=(nd-1)/(nF-nC)

In the present invention, the glass composition of glass is represented with oxide for benchmark.At this, " forming with the glass that oxide is benchmark " refers to, there is the glass composition carrying out converting and obtain in glass as oxide by setting frit and being all decomposed when melted.Additionally, unless otherwise specified, it is set to represent with quality for benchmark (quality %, mass ratio) by glass composition.

Glass composition in the present invention can pass through the methods such as such as ICP-AES (InductivelyCoupledPlasma-AtomicEmissionSpectrometry, ICP-AES) and obtain.Quantitative analysis uses ICP-AES to carry out respectively by each element.Hereafter, assay value is scaled represents with oxide.The assay value of ICP-AES sometimes comprise such as assay value ± evaluated error of about 5%.Accordingly, with respect to the value represented with oxide converted by assay value, sometimes also comprise ± the error of about 5% equally.

Additionally, in this specification and the present invention, the content of constituent is 0% or does not comprise or do not import and mean substantially not comprise this constituent, and the content referring to this constituent is below impurity level degree.

The heat stability of the glass used in this manual and devitrification resistance all mean the precipitation difficulty of the crystal in glass.The precipitation difficulty of the crystal when glass that have cured especially is reheated by the precipitation difficulty of the crystal in the precipitation difficulty that the precipitation difficulty of the crystal in glass includes the crystal in the glass of solution status and the glass that have cured, heat stability, devitrification resistance all include the above two meaning, simply heat stability refers mainly to the former, and devitrification resistance refers mainly to the latter.

Hereinafter, the glass composition of above-mentioned glass is described in detail.

B₂O₃It it is the composition playing the effect improving the heat stability of glass, meltbility.By improving meltbility such that it is able to obtain the glass not having the melted residual of frit, homogenizing.In order to obtain such effect, B₂O₃The preferred lower limit of content be 20%, preferred lower limit is 24%, it is preferred that lower limit be 26%.On the other hand, B is worked as₂O₃Content when increasing, the tendency that refractive index reduces can be shown.In order to obtain required optical characteristics, B while maintaining the heat stability of glass₂O₃The preferred upper limit of content be 34%, the preferred upper limit is 32%, it is preferred that the upper limit be 30%.

SiO₂Being optional member in above-mentioned glass, its content can be 0%.SiO₂Be for improve the heat stability of glass, devitrification resistance, chemical durability, melten glass is shaped by adjustment time the effective composition of viscosity.In order to obtain such effect, SiO₂The preferred lower limit of content be 1%.On the other hand, SiO is worked as₂Content when increasing, the tendency that meltbility reduces and refractive index also reduces of glass can be shown.In order to obtain required optical characteristics, SiO while maintaining the heat stability of glass, meltbility₂The preferred upper limit of content be 12%, the preferred upper limit is 9%, it is preferred that the upper limit be 7%.

P₂O₅It above-mentioned glass is also optional member.By a small amount of importing such that it is able to improve the stability of glass.P₂O₅The preferred upper limit of content be 1%, the preferred upper limit is 0.8%, it is preferred that the upper limit be 0.5%.Additionally, from the same viewpoint, P₂O₅The preferred lower limit of content be 0.1%, it is also possible to be 0%.

B₂O₃、SiO₂And P₂O₅It it is all the composition of the network forming glass.From the view point of stability, glass, B₂O₃、SiO₂And P₂O₅Total content (B₂O₃+SiO₂+P₂O₅) lower limit be preferably 25%, more preferably 28%, more preferably 29%.Additionally, for the refractive index improving glass, B₂O₃、SiO₂And P₂O₅The upper limit adding up to content be preferably 35%, more preferably 33%, more preferably 32%.

In above-mentioned glass, in order to improve the heat stability of glass, by SiO₂Content relative to the composition B of network forming glass₂O₃、SiO₂And P₂O₅Total content (B₂O₃+SiO₂+P₂O₅) mass ratio [SiO₂/(B₂O₃+SiO₂+P₂O₅)] lower limit be set to 0.050.Mass ratio [SiO₂/(B₂O₃+SiO₂+P₂O₅)] lower limit be preferably more than 0.060, more preferably more than 0.080, more preferably more than 0.100, be further preferably more than 0.120.Additionally, in order to give high-refractivity and low-dispersion characteristic, mass ratio [SiO₂/(B₂O₃+SiO₂+P₂O₅)] the upper limit be preferably less than 0.250, more preferably less than 0.200, more preferably less than 0.160, be further preferably less than 0.140.

Rare-earth oxide La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃、Lu₂O₃It it is all the composition with the effect improving refractive index when not improving dispersion (not reducing Abbe number).In order to improve refractive index, La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃And Lu₂O₃Total content (La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃；Hereinafter also above-mentioned rare-earth oxide is expressed as RE, also their total content is expressed as " content of RE ") lower limit be preferably 55%, more preferably 56%, more preferably 57%.From viewpoints such as the stability of glass, heat stability, devitrification resistances, the upper limit of the content of RE is preferably 65%, more preferably 62%, and more preferably 61%.

In rare-earth oxide RE, La₂O₃Even if being contain to obtain relatively compositions being not easy to reduce the heat stability of glass more.Therefore, in order to maintain glass and obtain heat stability, obtaining required optical characteristics, make the La containing more than 38% in above-mentioned glass₂O₃, it is preferred to containing more than 39%.In order to improve the stability of glass, devitrification resistance, La₂O₃The upper limit of content be 48%, it is preferred to 46%, more preferably 45%.

Gd₂O₃Be by above-mentioned glass with La₂O₃Coexist and be favorably improved the composition of heat stability.And then, Gd₂O₃Or improve the composition of refractive index.Therefore, in order to maintain the heat stability of glass, obtain required optical characteristics, make above-mentioned glass containing the Gd having more than 8.0%₂O₃, it is preferable that containing more than 8.5%.In order to improve the stability of glass, devitrification resistance, Gd₂O₃The upper limit of content be preferably 20%, more preferably 18%, more preferably 16%.

In above-mentioned glass, from the view point of improve heat stability, by Gd₂O₃Mass ratio [the Gd of the content content relative to rare-earth oxide RE₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃)] be set to less than 0.360.Mass ratio [Gd₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃)] the upper limit be preferably less than 0.330, more preferably less than 0.300, more preferably less than 0.250, be further preferably less than 0.230.Mass ratio [Gd₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃)] lower limit be preferably more than 0.050, more preferably more than 0.100, more preferably more than 0.150, be further preferably more than 0.200.

Y₂O₃Above-mentioned glass is optional member, it is also possible to its content is set to 0%.In order to maintain the heat stability of glass, obtain required optical characteristics, Y₂O₃The lower limit of content be preferably 2%, more preferably 3%.In order to improve the stability of glass, devitrification resistance, Y₂O₃The upper limit of content be preferably 14%, more preferably 10%, more preferably 8%.

Yb₂O₃、Lu₂O₃It above-mentioned glass is also optional member.In order to maintain the heat stability of glass, obtain required optical characteristics, Yb₂O₃、Lu₂O₃The lower limit respectively such as 1% of content, it is also possible to be set to 0%.Additionally, in order to improve the stability of glass, devitrification resistance, Yb₂O₃、Lu₂O₃The upper limit of content be respectively preferably 3%, more preferably 2.5%.

ZrO₂It is for improving refractive index and improving the effective composition of heat stability of glass.And then, or for improving the effective composition of chemical durability.In order to obtain such effect, ZrO₂The lower limit of content be preferably 6%, more preferably 7%.In order to improve the stability of glass, meltability and devitrification resistance, ZrO₂The upper limit of content be preferably 12%, more preferably 11%.

In above-mentioned glass, in order to improve the heat stability of glass, by B₂O₃、SiO₂And P₂O₅Total content relative to La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃、Lu₂O₃And ZrO₂Add up to content mass ratio [(B₂O₃+SiO₂+P₂O₅)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] it is set to more than 0.405.Mass ratio [(B₂O₃+SiO₂+P₂O₅)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] lower limit be preferably more than 0.407, more preferably more than 0.410, more preferably more than 0.420, be further preferably more than 0.430.In order to improve refractive index, by mass ratio [(B₂O₃+SiO₂+P₂O₅)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] be set to less than 0.460.Mass ratio [(B₂O₃+SiO₂+P₂O₅)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] the upper limit be preferably 0.455, more preferably 0.450.From the view point of improve heat stability, mass ratio [(B further₂O₃+SiO₂+P₂O₅)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] it is preferably more than 0.420 and less than 0.460.And then, more preferably refractive index nd range for 1.780～1.795, and mass ratio [(B₂O₃+SiO₂+P₂O₅)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] it is more than 0.420 and less than 0.460.

From the view point of reduce Abbe number and suppress painted, Nb₂O₅Content be set to less than 1.0%.Additionally, by making Nb₂O₅Content less than 1.0%, additionally it is possible to suppress glass painted.Nb₂O₅The upper limit of content be preferably 0.9%, more preferably 0.8%.Nb₂O₅Content can also be 0%.

From the view point of heat stability, ZrO₂And Nb₂O₅Total content (ZrO₂+Nb₂O₅) it is preferably less than 13%, more preferably less than 13%, more preferably less than 12%, further it is preferably less than 11%.Additionally, ZrO₂And Nb₂O₅Total content (ZrO₂+Nb₂O₅) lower limit be preferably 6%, more preferably 7%.

Ta₂O₅Being the optional member in above-mentioned glass, its content can be 0%.Because being expensive composition, there is again the tendency reducing devitrification resistance, it is preferable that limit it and import.From the view point of above, Ta₂O₅The upper limit of content be preferably 1.5%.

In order to give low dispersion characteristics to glass, in above-mentioned glass, by Ta₂O₅Content relative to La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃、Lu₂O₃And ZrO₂Add up to content mass ratio [Ta₂O₅/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] be set to less than 0.030.Mass ratio [Ta₂O₅/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] the upper limit be preferably less than 0.020, more preferably less than 0.015, more preferably less than 0.010, be further preferably less than 0.005.Because the Ta of above-mentioned glass₂O₅Content can be 0%, so mass ratio [Ta₂O₅/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] can also be 0.

TiO₂Also it is the composition of the effect playing the refractive index improving glass.From the view point of the low dispersion characteristics of glass, the heat stability of glass, chemical durability, suppression are painted, TiO₂Content preferably range for 0～2%, preferred range for 0～1%, it is also possible to be set to 0%.

WO₃Also it is the composition of the effect with the refractive index improving glass.From the view point of the heat stability of glass, suppress painted, WO₃Content be preferably more than 0% and less than 1%.WO₃Content be more preferably less than 0.5%, it is also possible to be set to 0%.

Bi₂O₃Play and improve refractive index and improve the effect of heat stability of glass.But, Bi₂O₃It it is the composition of the decrease in transmission making glass.Bi₂O₃Content preferably range for 0～3%, preferred range for 0～1%, it is preferred that range for 0～0.5%, further preferably range for 0～0.1%.It also is able to make Bi₂O₃Content be 0%.

In above-mentioned glass, in order to obtain low dispersion characteristics, by Nb₂O₅、TiO₂、WO₃And Bi₂O₃Total content relative to La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃、Lu₂O₃And ZrO₂Add up to content mass ratio [(Nb₂O₅+TiO₂+WO₃+Bi₂O₃)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] be set to less than 0.013.Mass ratio [(Nb₂O₅+TiO₂+WO₃+Bi₂O₃)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] the upper limit be preferably less than 0.012, more preferably less than 0.010, more preferably less than 0.08, be further preferably less than 0.06.Mass ratio [(Nb₂O₅+TiO₂+WO₃+Bi₂O₃)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] can also be 0.

A small amount of Al₂O₃Play and improve the heat stability of glass and the effect of chemical durability, but during excessive importing, have the tendency making the stability of glass, heat stability be deteriorated.From the viewpoint of above, Al₂O₃Content preferably range for 0～2%, it is also possible to make Al₂O₃Content be 0%.

Li₂O、Na₂O、K₂O、Cs₂O is all the optional member in above-mentioned glass.Li₂O、Na₂O、K₂O、Cs₂O has the effect of the meltbility improving glass.Additionally, also have the effect making glass transition temperature reduce.In order to obtain required refractive index, good heat stability and chemical durability, Li₂O、Na₂O、K₂O and Cs₂Total content (the Li of O₂O+Na₂O+K₂O+Cs₂O) preferably range for 0～5%, preferred range for 0～3%, it is preferred that range for 0～1%, it is also possible to be set to 0%.

GeO₂It is network forming oxide, i.e. be the network forming component of glass, also plays the effect improving refractive index.Therefore, it is able to improve the composition of refractive index while maintaining the heat stability of glass.But, because GeO₂It is much more expensive composition, so being the composition of its content of desired control.GeO₂Content preferably range for 0～3%.It also is able to make GeO₂Content be 0%.

MgO, CaO, SrO, BaO have the effect of the meltbility improving glass, but when the total (MgO+CaO+SrO+BaO) of content of each composition of MgO, CaO, SrO and BaO is more than 5%, refractive index can reduce, it is difficult to obtain required optical characteristics, and the tendency that the heat stability of glass reduces is shown.Therefore, in above-mentioned glass, the scope of the total content (MgO+CaO+SrO+BaO) of MgO, CaO, SrO and BaO is preferably set to 0～5%.The scope of above-mentioned total content is more preferably set to 0～3%, it is preferred that be set to 0～1%, it is also possible to be set to 0%.

ZnO is the composition with the effect improving the meltbility of glass, heat stability.In order to realize required optical characteristics, the upper limit of the content of ZnO is preferably 2%, more preferably 1.5%, and more preferably 1.3%, the lower limit of the content of ZnO is preferably 0.1%, it is also possible to be 0%.

The volatility of glass when F significantly increases melted.Therefore, in a mode, above-mentioned glass does not preferably contain F.On the other hand, F has the effect of the stability improving glass, and therefore by importing F, even if thus improving the content of rare-earth oxide RE, glass also becomes easy stabilisation.Therefore, in another mode, above-mentioned glass also is able to containing F.

In this specification and the present invention, the content of F is as F^-Content illustrate.F^-The upper limit of content be preferably 5%, more preferably 3%, more preferably 1%, be further preferably less than 0.5%, much further preferably from less than 0.4%, be more further preferably less than 0.3%.As it has been described above, F^-Content can also be 0%.

Sb₂O₃Can be added as clarifier, the effect of the reduction of the light transmittance that suppression causes owing to being mixed into the impurity such as Fe can be played by a small amount of interpolation, but work as Sb₂O₃Addition when increasing, the tendency of the painted increase of glass is shown owing to the light of Sb self absorbs.From above aspect, additional Sb₂O₃Addition range preferably from 0～1%.It addition, additional Sb₂O₃Content mean Sb₂O₃With the quality % Sb represented when the total of the content of glass ingredient in addition is set to 100 mass %₂O₃Content.Sb in table 1 described later₂O₃Content be also additional Sb₂O₃Content.

Considering environmental effect, above-mentioned glass does not preferably substantially comprise Pb.Substantially not comprising Pb, to mean to be converted into the content of PbO during PbO fewer than 0.05%, it is also possible to is 0%.

It addition, As, U, Th, Cd that environment is impacted be not it is also preferred that import.

Environment also can be impacted by Te, therefore imports substantial amounts of Te not preferred.TeO₂Content preferably range for 0～1%, preferred range for 0～0.5%, it is preferred that range for 0～0.1%, it is also possible to do not contain TeO₂。

And then, in order to play the outstanding light transmittance of glass, it is preferable that not importing Cu, Cr, V, Fe, Ni, Co etc. becomes the material of painted main cause.

Above-mentioned glass is high index of refraction, low dispersion, it is possible to becomes painted few glass, is adapted as optical glass.

Above, the glass composition of above-mentioned glass is illustrated.Then, the glass performance of above-mentioned glass is illustrated.

<glass physical property>

Above-mentioned optical glass is glass of high refractive index.Refractive index nd ranges for 1.78～1.80.The upper limit of refractive index nd is preferably less than 1.795, more preferably less than 1.793.The lower limit of refractive index nd is preferably more than 1.783, more preferably more than 1.785.In a mode, refractive index nd ranges preferably from 1.780～1.795.

Above-mentioned glass be above record there is high index of refraction and there is the high-refractivity and low-dispersion glass of low dispersion characteristics, its Abbe number ν d is more than 47, it is preferred to more than 47.5, more preferably more than 48.But, Abbe number ν d is less than 50.

Above-mentioned glass has high-refractivity and low-dispersion characteristic, and also can show which outstanding devitrification resistance.About devitrification resistance, the precipitation difficulty of crystal when especially reheating compacting, it may be said that crystallization temperature Tc is more high relative to glass transition temperature Tg is just the more outstanding optical glass of devitrification resistance.This is because, heating when reheating compacting carries out mostly near glass transition temperature.About this devitrification resistance, above-mentioned optical glass can show which the devitrification resistance meeting following (1) formula.

90 DEG C≤(Tc-Tg) ... (1)

Above-mentioned (1) formula is following (2) formula preferably, more preferably following (3) formula.

95 DEG C≤(Tc-Tg) ... (2)

100 DEG C≤(Tc-Tg) ... (3)

About glass transition temperature Tg, when glass transition temperature Tg is too low, the tendency that the processability illustrating the machinings such as grinding, polishing is reduced.Therefore, in order to maintain processability, it is preferable that making glass transition temperature Tg is more than 645 DEG C, more preferably more than 650 DEG C.

When annealing temperature, compressing time the temperature of glass become too high time, annealing furnace can be caused, be pressed into the consumption of pattern.In order to alleviate annealing furnace, the thermic load being pressed into pattern, glass transition temperature Tg is preferably less than 720 DEG C, more preferably less than 700 DEG C.

The glass of one mode of present invention mentioned above, its refractive index nd and Abbe number ν d are big, are useful as optical glass.

<manufacture method of glass>

Above-mentioned glass can obtain in the following manner: in the way of can obtaining the glass composition of target, weigh and allocate as the phosphate of raw material, fluoride, oxide etc., it is sufficiently mixed and makes batch mixture, heat in melt container, melt, carry out deaeration, stirring and make homogenizing and do not comprise the melten glass of bubble, by its molding.Specifically, it is possible to use well-known fusion method to make.

[compressing glass material, optical element blank and their manufacture method]

Another mode of the present invention relates to:

The compressing glass material being made up of above-mentioned glass；

The optical element blank being made up of above-mentioned glass；

The manufacture method of compressing glass material, it includes operation that above-mentioned glass ware forming is compressing glass material；And

The manufacture method of optical element blank, it includes being pressed into pattern and being pressed and make the operation of optical element blank by above-mentioned compressing glass material being used.

Optical element blank is that the shape with the optical element being set to target is approximate, adding grindings in shape, polish the optical element mother metal of surplus at optical element.By the surface of optical element blank is ground, polishes, thus completing optical element.The compressing glass material being made up of above-mentioned optical glass use when passing through heating and making it soften is pressed into pattern be pressed, it is possible to make optical element blank.

The compressing of compressing glass material can carry out in the following way, i.e. suppresses with the compressing glass material being pressed into the state that pattern is in softening to being heated.Heating, compressing all can carry out in an atmosphere.When the Powdered releasing agents such as the uniformly coating boron nitride at compressing glass material be heated, compressing time, melting of glass and shaping mould can not only be reliably prevented, additionally it is possible to make glass successfully extend along the forming surface being pressed into pattern.By being annealed reducing the stress of inside glass after compressing such that it is able to obtain the optical element blank of homogenizing.

On the other hand, compressing glass material is also referred to as prefabricated component, except with by the state of its former state for compressing prefabricated component except, also include by implement the machining such as cut-out, grinding, polishing and for compressing prefabricated component.As cutting-off method, there is following method: the method being referred to as delineation of the part intending cutting off on the surface of glass plate forms groove, from the pressure defining the back side in face of groove the part of groove is applied locality, in the method for the part break glass sheets of groove；The method utilizing cutter cutting glass plate, etc..Additionally, as Ginding process, the sphere processing employing curve generator, smooth processing etc. can be enumerated.As finishing method, the polishing employing the abrasive particle such as cerium oxide, zirconium oxide can be enumerated.

[optical element and manufacture method thereof]

Another mode of the present invention relates to:

The optical element being made up of above-mentioned optical glass；

The manufacture method (hereinafter referred to as " method A ") of optical element, it includes by being ground and/or polish, to above-mentioned optical element blank, the operation making optical element；And

The manufacture method (hereinafter referred to as " method B ") of optical element, it includes being pressed into pattern and being pressed and make the operation of optical element by above-mentioned compressing glass material being used.

In method a, if grind, well-known method is applied in polishing, by after processing optical element surface fully being cleaned, drying such that it is able to obtain inside quality and the high optical element of surface quality.The method that method A is adapted as manufacturing the optical elements such as various spherical lens, prism.

Compressing precision press molding method (being also referred to as optical mode molded) of can passing through in method B carries out, and in precision press molding method, forms the optical function face of optical element by transferring the forming surface being pressed into pattern.This, by optical element by light transmission or make light refraction, diffraction, reflection face be called optical function face.Such as lens, the aspheric surface of non-spherical lens, spherical lens the lens face such as sphere be equivalent to optical function face.Precision press molding method is thus by the compressing method forming optical function face by critically the forming surface being pressed into pattern is transferred to glass.That is, it is not necessary to be ground to complete optical function face, the machining such as polishing.Precision press molding method is suitable for manufacturing the optical element such as lens, lens arra, diffraction grating, prism, is most suitable especially as manufacturing the method for non-spherical lens on large-duty basis.

In an embodiment of precision press molding method, so that the glass constituting prefabricated component illustrates and ranges for 10⁵～10¹¹The mode of the viscosity of Pa s, reheats the prefabricated component that surface is clean state, utilizes the shaping mould with upper die and lower die that the prefabricated component after reheating is pressed.Mold release film can also be set as needed in the forming surface of shaping mould.It addition, from the viewpoint of the oxidation of the forming surface preventing shaping mould, compressing carry out preferably in nitrogen, inert gas environment.Compressing product are taken out from shaping mould, carries out slow cooling as required.When products formed is the optical elements such as lens, it is also possible to as needed in coating surface optical thin film.

In such manner, it is possible to manufacture the optical elements such as lens, lens arra, diffraction grating, prism.

Embodiment

Hereinafter, based on embodiment, the present invention is further described.But, the present invention is not limited to the mode shown in embodiment.

1. the making of glass No.1～No.32 and evaluation

In the way of can obtaining the glass of the composition shown in table 1, in frits such as phosphate corresponding with each glass ingredient for the ratio of regulation weighing 50～300g, fluoride, oxides, it is sufficiently mixed and is made allotment batch of material.Allotment batch of material is put into platinum crucible cover lid, stirs, at 1150～1400 DEG C, the melting carried out in atmosphere or in nitrogen environment 1～3 hour.After melting, glass melts is flowed in the carbon die of 40 × 70 × 15mm, annealing furnace is put at once after placement is cooled to glass transition temperature, annealing in about 1 hour is carried out in glass transition temperature range, place in stove and be cooled to room temperature, resulting in each glass of the composition with No.1～No.32.

The refractive index of each glass, Abbe number, glass transition temperature Tg, crystallization temperature Tc is determined by following method.

The glass made all does not find the melted residual of the precipitation of crystal, bubble, striped, raw material.In such manner, it is possible to make the glass that homogeneity is high.

Assay method

Glass composition shown in table 1, table 2 and physical property are obtained by following method.

(1) refractive index (nd) and Abbe number (ν d)

It is that-30 DEG C/h of optical glass obtained are measured by the method for minimum deviation angle to making slow cooling cooling rate.

(2) glass transition temperature Tg

Make programming rate be 10 DEG C/minute by differential scanning calorimeter (DSC (DifferentialScanningCalorimetry)) to be measured.

(3) crystallization temperature Tc

Make programming rate be 10 DEG C/minute by differential scanning calorimeter (DSC (DifferentialScanningCalorimetry)) to be measured.It addition, the temperature by the initial exothermic peak occurred at DSC curve when glass specimen is heated up is set to crystallization temperature Tc.

(4) glass composition

The content of each composition is obtained by ICP-AES (ICP-AES method) or the chromatography of ions.

[table 1]

[table 2]

The evaluation of heat stability

In the way of can obtaining having the glass of each composition shown in table 1, allocate frit, each mediation raw material 150g put in platinum crucible, 1350 DEG C of heating, melted 120 minutes, then cool down fused mass and obtain solidfied material.Solidfied material is observed, and result does not precipitate out crystal.And then, glass is kept 120 minutes also without precipitating out crystal at 1100 DEG C, maintenance temperature is reduced to 1060 DEG C and keeps, still without precipitating out crystal.

According to above result, can confirm that the glass shown in table 1 has high heat stability.

2. the making of the glass of comparative example 1,2 and evaluation

Except except employing the frits such as the phosphate corresponding with each glass ingredient, fluoride, oxide in the way of can obtaining the glass of the composition shown in table 3, make glass by the method with glass No.1～same for No.32.

In comparative example 1 and comparative example 2, the glass obtained all has many crystal to precipitate out, and fails to measure refractive index and Abbe number.

As it has been described above, the glass of comparative example 1,2 is the glass of poor heat stability.

[table 3]

3. the making of optical element blank and optical element

Clarification that preparation can obtain each glass of No.1～No.32, the melten glass homogenized, make it be flowed into so that firm discharge continuously flows out from platinum tubulation and be flatly arranged in the mold of a sidewall opening below pipe, while being shaped to the glass plate with fixing width and fixing thickness, pull out the glass plate of molding from the peristome of mold.It is annealed the glass plate of pull-out processing in annealing furnace, reduces stress, obtain there is no striped, foreign body, painted few glass plate being made up of above-mentioned each glass.

Then, these each glass plates are cut off in length and breadth, obtain the sheet glass of multiple rectangular shape with same size.And then multiple sheet glass are carried out tumbling, make compressing glass gob matchingly with the weight of the compressing product as target.

Additionally, it is different from above-mentioned method, melten glass can also be made to flow out from platinum nozzle with fixed flow rate, the lower section that multiple undertaking moulds are sequentially transmitted this nozzle accepts the fused glass block of definite quality successively, these fused glass blocks are shaped to spherical or rotary body shape, implement grinding, polishing after being annealed process, make compressing glass gob matchingly with the quality of the compressing product as target.

Releasing agent at the whole surface coating powder shape of above-mentioned each glass gob, such as boron nitride powder, it is made to soften with heater heating, then put into there are upper die and lower die be pressed in pattern, carrying out pressurizeing with being pressed into pattern and be shaped to each lens blank, the shape of this lens blank is approximate with at the lens as the consumption surplus adding grindings, polishing on the lens shape of target.

It follows that each lens blank is annealed process to reduce stress.The enforcement grinding of chilled lens blank, polishing are completed the lens as target.It addition, a series of operation carries out in an atmosphere.The each lens obtained are respectively provided with outstanding transmitance.It also is able to as required to optical multilayers such as lens plating antireflection films.

Utilize such lens can constitute good image pickup optical system.

It addition, be pressed into the volume of the shape of pattern, glass gob by suitably setting, thus other the optical element such as prism can also be manufactured.

4. the making of precision press molding prefabricated component

The high-quality that can obtain each glass of No.1～No.32 and the melten glass that homogenizes is made to continuously flow out from the pipe of platinum alloy.Make the melten glass of outflow drip from pipe flow outlet, accept successively with multiple prefabricated component shaping moulds, multiple spherical prefabricated components by floating method of forming molding.

The prefabricated component microscope obtained with each glass of No.1～No.32, not it is observed that crystal, is transparent and homogenizing.The all non-devitrification of these prefabricated components, obtains the prefabricated component of high-quality precision.

The process of chopping replace dripping each glass of method No.1～No.32 in whereabouts is used to make prefabricated component.The prefabricated component obtained by the whereabouts process of chopping does not find devitrification too, obtains the prefabricated component of high-quality precision.Additionally, drip, method, the whereabouts process of chopping all do not find vestige when separating in prefabricated component.Even if using platinum tubulation also identical with platinum alloy tubulation, it does not have cause pipe damaged due to the outflow of melten glass.

5. the making of optical element

Plating is implemented on surface as needed in above-mentioned prefabricated component, it is conducted into including being pressed in pattern what forming surface was provided with the upper and lower mould of SiC of carbons mold release film and body mould, being heated together with prefabricated component by shaping mould in nitrogen environment makes prefabricated component soften, carry out precision press molding and made be made up of above-mentioned various glass aspheric surface male bend moon-shaped lens, the recessed meniscus lens of aspheric surface, aspheric surface biconvex lens, aspheric surface biconcave lens various lens.It addition, have adjusted each condition of precision press molding in aforesaid scope.

When observing the various lens so made, at lens surface entirely without finding scar, opaque, damaged.

It is repeatedly performed such process and has carried out the volume production test of various lens, it does not have it is bad with melting etc. of being pressed into pattern to produce glass, it is possible to made with high precision surface and the internal lens being high-quality.Can also at the coating surface antireflection film of the lens so obtained.

Next, the prefabricated component same with above-mentioned prefabricated component is heated, softens, import to be additionally carried out preheating be pressed into pattern, carry out precision press molding and made be made up of above-mentioned various glass aspheric surface male bend moon-shaped lens, the recessed meniscus lens of aspheric surface, aspheric surface biconvex lens, aspheric surface biconcave lens various lens.It addition, have adjusted each condition of precision press molding in aforesaid scope.

When observing the various lens so made, it does not have find by point nebulousurine etc. caused mutually, at lens surface entirely without finding scar, opaque, damaged.

It is repeatedly performed such process and has carried out the volume production test of various lens, it does not have it is bad with melting etc. of being pressed into pattern to produce glass, it is possible to made with high precision surface and the internal lens being high-quality.Can also at the coating surface antireflection film of the lens so obtained.

It also is able to the shape suitably changing the forming surface being pressed into pattern to make the various optical elements such as prism, lenticule, lens arra.

Finally, above-mentioned each mode is summarized.

According to a mode, using the teaching of the invention it is possible to provide a kind of glass, wherein, in the glass composition being benchmark with oxide, Nb₂O₅、TiO₂、WO₃And Bi₂O₃Total content relative to La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃、Lu₂O₃And ZrO₂Add up to content mass ratio [(Nb₂O₅+TiO₂+WO₃+Bi₂O₃)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] less than 0.013, Ta₂O₅Content relative to La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃、Lu₂O₃And ZrO₂Add up to content mass ratio [Ta₂O₅/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] less than 0.030, B₂O₃、SiO₂And P₂O₅Total content relative to La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃、Lu₂O₃And ZrO₂Add up to content mass ratio [(B₂O₃+SiO₂+P₂O₅)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] it is more than 0.405 and less than 0.460, SiO₂Content relative to B₂O₃、SiO₂And P₂O₅Add up to content mass ratio [SiO₂/(B₂O₃+SiO₂+P₂O₅)] it is 0.050～0.250, Gd₂O₃Content relative to La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃And Lu₂O₃Add up to content mass ratio [Gd₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃)] less than 0.360, Gd₂O₃Content more than 8.0 mass %, La₂O₃Content be 38～48 mass %, Nb₂O₅Content range for 1.78～1.80 less than 1.0 mass %, refractive index nd, and Abbe number ν d range for 47～50.

The above-mentioned glass composition adjustment by above recording such that it is able to illustrate outstanding heat stability, and can show which refractive index nd and the high-refractivity and low-dispersion characteristic of Abbe number ν d respectively above-mentioned scope.

From the view point of improve heat stability, preferred mass ratio [(B in above-mentioned glass further₂O₃+SiO₂+P₂O₅)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] it is more than 0.420 and less than 0.460.

From the view point of further improve heat stability, preferred mass ratio [(B in above-mentioned glass₂O₃+SiO₂+P₂O₅)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] be more than 0.420 and less than 0.460, and refractive index nd range for 1.780～1.795.

Above-mentioned glass preferably meets more than following 1.

Mass ratio [SiO₂/(B₂O₃+SiO₂+P₂O₅)] range for 0.060～0.200.

Mass ratio [Gd₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃)] it is less than 0.330.

Mass ratio [Ta₂O₅/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] it is less than 0.020.

Mass ratio [(Nb₂O₅+TiO₂+WO₃+Bi₂O₃)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] it is less than 0.012.

Above-mentioned glass is adapted as the glass for obtaining compressing glass material, optical element blank and optical element.

That is, according to another mode, it is possible to provide a kind of compressing glass material, optical element blank and optical element being made up of above-mentioned glass.

Additionally, according to another mode, it is possible to provide the manufacture method of a kind of compressing glass material, it includes operation that above-mentioned glass ware forming is compressing glass material.

Additionally, according to another mode, may also provide the manufacture method of a kind of optical element blank, it includes being pressed into pattern and being pressed and make the operation of optical element blank by above-mentioned compressing glass material being used.

According to another mode, may also provide the manufacture method of a kind of optical element, it includes by being ground and/or polish, to above-mentioned optical element blank, the operation making optical element.

According to another mode, may also provide the manufacture method of a kind of optical element, it includes being pressed into pattern and being pressed and make the operation of optical element by above-mentioned compressing glass material being used.

It is believed that this time disclosed embodiment is all exemplary rather than restrictive in all of.The scope of the present invention is not illustrated by above-mentioned explanation, but is illustrated by claims, including all of change in the meaning being equal to claims and scope.

Such as, by foregoing illustrative glass composition is illustrated the composition adjustment described in book such that it is able to obtain the optical glass of a mode of the present invention.

Additionally, certainly can in the description illustratively or preferred scope and 2 combination in any carried out above in the item recorded.

Industrial applicability

The present invention is useful in the manufacture field of the various optical elements such as glass lens, lens arra, diffraction grating, prism.

Claims (10)

1. a glass, wherein,

In the glass composition being benchmark with oxide,

SiO₂Content relative to B₂O₃、SiO₂And P₂O₅Add up to content mass ratio [SiO₂/(B₂O₃+SiO₂+P₂O₅)] it is 0.050～0.250,

Gd₂O₃Content relative to La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃And Lu₂O₃Add up to content mass ratio [Gd₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃)] less than 0.360,

B₂O₃、SiO₂And P₂O₅Total content relative to La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃、Lu₂O₃And ZrO₂Add up to content mass ratio [(B₂O₃+SiO₂+P₂O₅)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] it is more than 0.405 and less than 0.460,

Ta₂O₅Content relative to La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃、Lu₂O₃And ZrO₂Add up to content mass ratio [Ta₂O₅/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] less than 0.030,

Nb₂O₅、TiO₂、WO₃And Bi₂O₃Total content relative to La₂O₃、Gd₂O₃、Y₂O₃、Yb₂O₃、Lu₂O₃And ZrO₂Add up to content mass ratio [(Nb₂O₅+TiO₂+WO₃+Bi₂O₃)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] less than 0.013,

Gd₂O₃Content more than 8.0 mass %,

La₂O₃Content be 38～48 mass %,

Nb₂O₅Content less than 1.0 mass %,

Refractive index nd ranges for 1.78～1.80, and Abbe number ν d range for 47～50.

2. glass as claimed in claim 1, wherein,

Mass ratio [(B₂O₃+SiO₂+P₂O₅)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] it is more than 0.420 and less than 0.460.

3. glass as claimed in claim 2, wherein,

Refractive index nd ranges for 1.780～1.795.

4. the glass as described in any one of claims 1 to 3, wherein,

Mass ratio [SiO₂/(B₂O₃+SiO₂+P₂O₅)] range for 0.060～0.200.

5. the glass as described in any one of Claims 1 to 4, wherein,

Mass ratio [Gd₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃)] it is less than 0.330.

6. the glass as described in any one of Claims 1 to 5, wherein,

Mass ratio [Ta₂O₅/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] it is less than 0.020.

7. the glass as described in any one of claim 1～6, wherein,

Mass ratio [(Nb₂O₅+TiO₂+WO₃+Bi₂O₃)/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃+Lu₂O₃+ZrO₂)] it is less than 0.012.

8. a compressing glass material, the glass described in any one of claim 1～7 is constituted.

9. an optical element blank, the glass described in any one of claim 1～7 is constituted.

10. an optical element, the glass described in any one of claim 1～7 is constituted.