CN117945648A - Glass, optical glass and optical element - Google Patents
Glass, optical glass and optical element Download PDFInfo
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- CN117945648A CN117945648A CN202410024209.5A CN202410024209A CN117945648A CN 117945648 A CN117945648 A CN 117945648A CN 202410024209 A CN202410024209 A CN 202410024209A CN 117945648 A CN117945648 A CN 117945648A
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- 239000005304 optical glass Substances 0.000 title claims abstract description 335
- 230000003287 optical effect Effects 0.000 title claims abstract description 166
- 239000011521 glass Substances 0.000 title abstract description 761
- 239000006185 dispersion Substances 0.000 claims abstract description 189
- 230000036961 partial effect Effects 0.000 claims abstract description 168
- ZKATWMILCYLAPD-UHFFFAOYSA-N niobium pentoxide Chemical compound O=[Nb](=O)O[Nb](=O)=O ZKATWMILCYLAPD-UHFFFAOYSA-N 0.000 claims description 590
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 366
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 294
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 211
- 230000005484 gravity Effects 0.000 claims description 194
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 185
- 229910052681 coesite Inorganic materials 0.000 claims description 105
- 229910052906 cristobalite Inorganic materials 0.000 claims description 105
- 239000000377 silicon dioxide Substances 0.000 claims description 105
- 229910052682 stishovite Inorganic materials 0.000 claims description 105
- 229910052905 tridymite Inorganic materials 0.000 claims description 105
- 229910004742 Na2 O Inorganic materials 0.000 claims description 102
- 230000004075 alteration Effects 0.000 abstract description 27
- 238000012937 correction Methods 0.000 abstract description 22
- 239000005368 silicate glass Substances 0.000 abstract description 8
- KKCBUQHMOMHUOY-UHFFFAOYSA-N Na2O Inorganic materials [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 168
- 230000002829 reductive effect Effects 0.000 description 125
- WMWLMWRWZQELOS-UHFFFAOYSA-N bismuth(iii) oxide Chemical compound O=[Bi]O[Bi]=O WMWLMWRWZQELOS-UHFFFAOYSA-N 0.000 description 112
- FUJCRWPEOMXPAD-UHFFFAOYSA-N Li2O Inorganic materials [Li+].[Li+].[O-2] FUJCRWPEOMXPAD-UHFFFAOYSA-N 0.000 description 109
- XUCJHNOBJLKZNU-UHFFFAOYSA-M dilithium;hydroxide Chemical compound [Li+].[Li+].[OH-] XUCJHNOBJLKZNU-UHFFFAOYSA-M 0.000 description 109
- 230000009477 glass transition Effects 0.000 description 92
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 78
- 238000003303 reheating Methods 0.000 description 57
- 230000000694 effects Effects 0.000 description 50
- 238000002834 transmittance Methods 0.000 description 49
- 239000007791 liquid phase Substances 0.000 description 47
- 230000007423 decrease Effects 0.000 description 41
- 239000002994 raw material Substances 0.000 description 40
- 238000004519 manufacturing process Methods 0.000 description 35
- PBCFLUZVCVVTBY-UHFFFAOYSA-N tantalum pentoxide Inorganic materials O=[Ta](=O)O[Ta](=O)=O PBCFLUZVCVVTBY-UHFFFAOYSA-N 0.000 description 34
- 239000013078 crystal Substances 0.000 description 33
- 238000002844 melting Methods 0.000 description 33
- 230000008018 melting Effects 0.000 description 33
- 239000000203 mixture Substances 0.000 description 33
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 28
- 230000003595 spectral effect Effects 0.000 description 28
- 238000002425 crystallisation Methods 0.000 description 27
- 230000008025 crystallization Effects 0.000 description 27
- KOPBYBDAPCDYFK-UHFFFAOYSA-N Cs2O Inorganic materials [O-2].[Cs+].[Cs+] KOPBYBDAPCDYFK-UHFFFAOYSA-N 0.000 description 25
- AKUNKIJLSDQFLS-UHFFFAOYSA-M dicesium;hydroxide Chemical compound [OH-].[Cs+].[Cs+] AKUNKIJLSDQFLS-UHFFFAOYSA-M 0.000 description 25
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum oxide Inorganic materials [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 description 25
- 238000000034 method Methods 0.000 description 25
- KTUFCUMIWABKDW-UHFFFAOYSA-N oxo(oxolanthaniooxy)lanthanum Chemical compound O=[La]O[La]=O KTUFCUMIWABKDW-UHFFFAOYSA-N 0.000 description 25
- 238000004031 devitrification Methods 0.000 description 24
- 239000006060 molten glass Substances 0.000 description 22
- 230000007547 defect Effects 0.000 description 21
- 238000010438 heat treatment Methods 0.000 description 18
- 239000000126 substance Substances 0.000 description 17
- 238000012360 testing method Methods 0.000 description 17
- 229910005793 GeO 2 Inorganic materials 0.000 description 16
- 229910052697 platinum Inorganic materials 0.000 description 14
- 229910018068 Li 2 O Inorganic materials 0.000 description 13
- CMIHHWBVHJVIGI-UHFFFAOYSA-N gadolinium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Gd+3].[Gd+3] CMIHHWBVHJVIGI-UHFFFAOYSA-N 0.000 description 13
- CJNBYAVZURUTKZ-UHFFFAOYSA-N hafnium(IV) oxide Inorganic materials O=[Hf]=O CJNBYAVZURUTKZ-UHFFFAOYSA-N 0.000 description 12
- 230000015572 biosynthetic process Effects 0.000 description 11
- 238000004040 coloring Methods 0.000 description 10
- 230000005499 meniscus Effects 0.000 description 10
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 9
- 229910052593 corundum Inorganic materials 0.000 description 9
- 239000000463 material Substances 0.000 description 9
- 229910001845 yogo sapphire Inorganic materials 0.000 description 9
- 230000009471 action Effects 0.000 description 8
- 229910052792 caesium Inorganic materials 0.000 description 8
- YBMRDBCBODYGJE-UHFFFAOYSA-N germanium dioxide Chemical compound O=[Ge]=O YBMRDBCBODYGJE-UHFFFAOYSA-N 0.000 description 8
- 238000003384 imaging method Methods 0.000 description 8
- 239000000470 constituent Substances 0.000 description 7
- 238000000227 grinding Methods 0.000 description 7
- 230000009467 reduction Effects 0.000 description 7
- 238000001816 cooling Methods 0.000 description 6
- 239000006025 fining agent Substances 0.000 description 6
- WZFUQSJFWNHZHM-UHFFFAOYSA-N 2-[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]piperazin-1-yl]-1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethanone Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)N1CCN(CC1)CC(=O)N1CC2=C(CC1)NN=N2 WZFUQSJFWNHZHM-UHFFFAOYSA-N 0.000 description 5
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 5
- 229910000272 alkali metal oxide Inorganic materials 0.000 description 5
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 5
- 238000004993 emission spectroscopy Methods 0.000 description 5
- 238000011156 evaluation Methods 0.000 description 5
- 150000004679 hydroxides Chemical class 0.000 description 5
- 239000012535 impurity Substances 0.000 description 5
- 238000009616 inductively coupled plasma Methods 0.000 description 5
- 238000000465 moulding Methods 0.000 description 5
- 150000002823 nitrates Chemical class 0.000 description 5
- 238000005191 phase separation Methods 0.000 description 5
- 238000005498 polishing Methods 0.000 description 5
- 238000007088 Archimedes method Methods 0.000 description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- 238000005352 clarification Methods 0.000 description 4
- 238000012790 confirmation Methods 0.000 description 4
- 230000007613 environmental effect Effects 0.000 description 4
- 230000003628 erosive effect Effects 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 230000001771 impaired effect Effects 0.000 description 4
- 229910003443 lutetium oxide Inorganic materials 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 238000000691 measurement method Methods 0.000 description 4
- 239000002244 precipitate Substances 0.000 description 4
- HYXGAEYDKFCVMU-UHFFFAOYSA-N scandium(III) oxide Inorganic materials O=[Sc]O[Sc]=O HYXGAEYDKFCVMU-UHFFFAOYSA-N 0.000 description 4
- HMUNWXXNJPVALC-UHFFFAOYSA-N 1-[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]piperazin-1-yl]-2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethanone Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)N1CCN(CC1)C(CN1CC2=C(CC1)NN=N2)=O HMUNWXXNJPVALC-UHFFFAOYSA-N 0.000 description 3
- VZSRBBMJRBPUNF-UHFFFAOYSA-N 2-(2,3-dihydro-1H-inden-2-ylamino)-N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]pyrimidine-5-carboxamide Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C(=O)NCCC(N1CC2=C(CC1)NN=N2)=O VZSRBBMJRBPUNF-UHFFFAOYSA-N 0.000 description 3
- 229910003069 TeO2 Inorganic materials 0.000 description 3
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 3
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 239000008395 clarifying agent Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 229910052733 gallium Inorganic materials 0.000 description 3
- 238000003825 pressing Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 238000007670 refining Methods 0.000 description 3
- LAJZODKXOMJMPK-UHFFFAOYSA-N tellurium dioxide Chemical compound O=[Te]=O LAJZODKXOMJMPK-UHFFFAOYSA-N 0.000 description 3
- 229910052720 vanadium Inorganic materials 0.000 description 3
- 238000000137 annealing Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000007731 hot pressing Methods 0.000 description 2
- 238000001095 inductively coupled plasma mass spectrometry Methods 0.000 description 2
- 229910052745 lead Inorganic materials 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- OHVLMTFVQDZYHP-UHFFFAOYSA-N 1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)-2-[4-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]piperazin-1-yl]ethanone Chemical compound N1N=NC=2CN(CCC=21)C(CN1CCN(CC1)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)=O OHVLMTFVQDZYHP-UHFFFAOYSA-N 0.000 description 1
- LDXJRKWFNNFDSA-UHFFFAOYSA-N 2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)-1-[4-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]piperazin-1-yl]ethanone Chemical compound C1CN(CC2=NNN=C21)CC(=O)N3CCN(CC3)C4=CN=C(N=C4)NCC5=CC(=CC=C5)OC(F)(F)F LDXJRKWFNNFDSA-UHFFFAOYSA-N 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 239000006063 cullet Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 150000002222 fluorine compounds Chemical class 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 239000005401 pressed glass Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 230000003252 repetitive effect Effects 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 238000010583 slow cooling Methods 0.000 description 1
- 238000004017 vitrification Methods 0.000 description 1
- 239000013585 weight reducing agent Substances 0.000 description 1
Landscapes
- Glass Compositions (AREA)
Abstract
The invention provides a glass, an optical glass and an optical element which have good hot-press formability and are suitable for secondary chromatic aberration correction. The solution is that silicate glass has Abbe number vd of 20-35, contains P 2O5 and Nb 2O5, and has relative partial dispersion Pg and F satisfying the formula (1-1): pg, F is less than or equal to-0.00286 Xvd+ 0.68900 (1-1).
Description
The application is a divisional application of application No. 201880035996.6, with the application name of 'glass, optical glass and optical element', which is filed on the date of application of 2018, 05 and 31.
Technical Field
The present invention relates to glass, optical glass, and optical element.
In the design of an optical system, an optical glass having a high refractive index and high dispersibility is highly useful in correcting chromatic aberration and in making the optical system highly functional and compact.
The following describes the glass according to the 1 st, 2 nd, 3 rd and 4 th inventions.
In the present invention and the present specification, unless otherwise specified, the glass composition is expressed on an oxide basis. The term "oxide-based glass composition" as used herein refers to a glass composition obtained by converting substances existing in the form of oxides in glass in accordance with all of the glass raw materials decomposed at the time of melting, and the expression of each glass composition is conventionally described as SiO 2、TiO2 or the like. Unless otherwise specified, the content of the glass component and the total content are referred to as "mass%".
The content of the glass component can be quantified by a known method, for example, inductively coupled plasma emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), or the like. In the present specification and the present invention, a content of 0% of a constituent component means that the constituent component is substantially not contained, and the constituent component is allowed to be contained at an unavoidable impurity level.
In the present specification, unless otherwise specified, the refractive index means the refractive index nd of helium at d-ray (wavelength 587.56 nm).
The abbe number vd is used as a value indicating a property related to dispersion, and is expressed by the following formula. Here, nF is the refractive index of blue hydrogen at F-ray (wavelength 486.13 nm), and nC is the refractive index of red hydrogen at C-ray (656.27 nm).
νd＝(nd-1)/(nF-nC)
1 St invention
[ Background of the invention 1]
As a method for producing an optical glass used in an optical system, a reheat press method in which glass is reheated and shaped is given. In this method, in the silicate-based optical glass having a high refractive index and high dispersibility, phase separation is likely to occur during reheating. If phase separation occurs, fluidity of the glass at the time of reheating becomes poor, and it may be difficult to form the glass into a desired shape. In addition, this phase separation causes internal defects (for example, bright spots, cracks, streaks, and the like on reflected light) in optical elements such as lenses. Therefore, in the reheat press method, there is a demand for a silicate-based optical glass having a high refractive index and high dispersibility, which can be formed into a desired shape, that is, has good reheat press formability, while suppressing the occurrence of internal defects.
In addition, in the design of the optical system, the primary chromatic aberration correction may be performed by combining two kinds of glasses having different abbe numbers. The glass used for the secondary chromatic aberration correction is selected in consideration of the relative partial dispersion in addition to the abbe number. Particularly, among optical glasses having a high refractive index and high dispersibility, optical glasses having a small relative partial dispersion are suitable for secondary chromatic aberration correction.
Silicate-based optical glasses with high refractive index and high dispersibility are disclosed in patent documents 1-1 to 1-5. However, from the viewpoints of abbe number and relative partial dispersion, it is required to further improve the secondary chromatic aberration correction for any glass.
[ Prior Art document of the invention 1]
Patent literature
Patent document 1-1: japanese patent laid-open No. 2001-342035
Patent documents 1 to 2: japanese patent application laid-open No. 2012-206894
Patent documents 1 to 3: japanese patent application laid-open No. 2014-201636
Patent documents 1 to 4: japanese patent laid-open No. 60-21828
Patent documents 1 to 5: japanese patent laid-open No. 59-8637
[1 St summary ]
[ Problem to be solved by the invention 1]
The invention 1 is made in view of the above-described circumstances, and an object thereof is to provide a glass, an optical glass, and an optical element which have good reheat press formability and are suitable for secondary chromatic aberration correction.
[ Means of solving the problems ]
The gist of the invention 1 is as follows.
[1] Silicate glass with Abbe number vd of 20-35,
Contains P 2O5 and Nb 2O5,
And the relative partial dispersion Pg, F satisfies the following formula (1-1):
Pg,F≤-0.00286×νd+0.68900···(1-1)。
[2] Silicate glass with Abbe number vd of 20-35,
Contains P 2O5 and Nb 2O5,
And the mass ratio of the content of Nb 2O5 to the total content of Nb 2O5、TiO2、WO3 and Bi 2O3 [ Nb 2O5/(Nb2O5+TiO2+WO3+Bi2O3) ] is larger than 0.6110.
[3] An optical glass formed from the glass of [1] or [2 ].
[4] An optical element formed of the optical glass described in the above [3 ].
[ Effect of the invention 1]
According to the invention of claim 1, a glass, an optical glass, and an optical element which have excellent reheat press formability and are suitable for secondary chromatic aberration correction can be provided.
[ Detailed description of the invention 1]
Hereinafter, the glass according to embodiment 1 of the present invention will be described in detail. First, as embodiment 1-1, a glass will be described from the viewpoint of relative partial dispersion Pg, F, and as embodiment 1-2, a glass will be described from the viewpoint of the mass ratio of glass components. Further, as another embodiment, embodiment a, embodiment B, and embodiment C will be described.
Embodiment 1 to 1
The glass of embodiment 1-1 is a silicate glass having an Abbe number vd of 20 to 35,
Contains P 2O5 and Nb 2O5,
And the relative partial dispersion Pg, F satisfies the following formula (1-1),
Pg,F≤-0.00286×νd+0.68900…(1-1)。
The glass of embodiment 1-1 is a silicate glass mainly containing SiO 2 as a network forming component of the glass. The content of SiO 2 is preferably more than 0%, and the lower limit thereof is more preferably in the order of 1%, 5%, 10%, 15%, 20%, 25%. The upper limit of the content of SiO 2 is preferably 60%, more preferably in the order of 50%, 40%, 39%, 38%, 37%, 36%, 35%.
SiO 2 is used as a network forming component of glass, and has the functions of improving the thermal stability, chemical durability and weather resistance of the glass, increasing the viscosity of the molten glass and facilitating the forming of the molten glass. On the other hand, when the content of SiO 2 is large, the devitrification resistance of the glass tends to be lowered, and Pg and F are increased. Therefore, the content of SiO 2 is preferably set to the above range.
The lower limit of the content of P 2O5.P2O5 in the glass of embodiment 1-1 is preferably 0.1%, more preferably in the order of 0.3%, 0.5%, 0.7%, 0.9%, 1.1%, 1.3%, 1.5%, 1.7%, 1.9%. The upper limit of the content of P 2O5 is preferably 10%, more preferably 7%, 5% and 3%.
By making the lower limit of the content of P 2O5 satisfy the above range, the reheat press formability can be improved. Further, when the upper limit of the content of P 2O5 is set to the above range, the increase in the relative partial dispersions Pg and F can be suppressed, the thermal stability of the glass can be maintained, and the reheat press formability can be improved.
The lower limit of the content of Nb 2O5.Nb2O5 in the glass of embodiment 1-1 may be 1%, or may be 10%, 20%, 24%, 25%, 30%, 35%, 40%, or 43%. The upper limit of the content of Nb 2O5 is preferably 80%, more preferably in the order of 60%, 55%, 50%, 45%.
When the lower limit of the content of Nb 2O5 is set to the above range, a glass having a reduced relative partial dispersion Pg, F and a high refractive index and high dispersibility can be obtained. Nb 2O5 is also a glass component for improving the thermal stability and chemical durability of the glass. Therefore, by setting the upper limit of the content of Nb 2O5 to the above range, the thermal stability and chemical durability of the glass can be well maintained, and the reheat press formability can be improved.
In the glass of embodiment 1-1, abbe number vd is 20 to 35. The Abbe number vd may be 22 to 33, 23 to 31, 23 to 27, or 23 to 26.
By setting the Abbe number vd in the above range, a glass with high dispersibility can be obtained.
The Abbe number vd can be controlled by adjusting the content of Nb 2O5、TiO2、WO3 and Bi 2O3 as glass components contributing to high dispersion.
In the glass of embodiment 1-1, the relative partial dispersion Pg, F satisfies the following formula (1-2). The relative partial dispersion Pg, F preferably satisfies the following formula (1-3), more preferably satisfies the following formula (1-4), and still more preferably satisfies the following formula (1-5). By making the relative partial dispersion Pg, F satisfy the following expression, an optical glass suitable for secondary chromatic aberration correction can be provided.
Pg,F≤-0.00286×νd+0.68900···(1-2)
Pg,F≤-0.00286×νd+0.68800···(1-3)
Pg,F≤-0.00286×νd+0.68600···(1-4)
Pg,F≤-0.00286×νd+0.68400···(1-5)
The relative partial dispersion Pg, F can be expressed by the following formulas (1 to 6) using the refractive indices ng, nF, nC in g-ray, F-ray, and C-ray.
Pg,F＝(ng-nF)/(nF-nC)···(1-6)
The relative partial dispersion Pg, F is controlled by adjusting the mass ratio [(Li2O+Na2O+K2O+Cs2O)/(SiO2+P2O5+B2O3)]、 mass ratio [(Li2O+Na2O+K2O+Cs2O)/(Nb2O5+TiO2+WO3+Bi2O3)]、 mass ratio [(SiO2+P2O5+B2O3)/(Nb2O5+TiO2+WO3+Bi2O3)]、 mass ratio [ ZrO 2/(Nb2O5+TiO2+WO3+Bi2O3 ], mass ratio [ P 2O5/(SiO2+P2O5+B2O3 ], mass ratio [ Nb 2O5/(Nb2O5+TiO2+WO3+Bi2O3) ], mass ratio [ (mgo+cao+sro+bao+zno)/(Li 2O+Na2O+K2O+Cs2 O) ] described later.
(Glass component)
The content and ratio of the glass components other than those described above in embodiment 1 to embodiment 1 of the invention 1 will be described in detail below.
In the glass of embodiment 1 to 1, the content of B 2O3 is preferably 20% or less, more preferably 10% or less, 5% or less, 3% or less, and 1% or less. The content of B 2O3 may also be 0%.
B 2O3 is a network forming component of the glass, and has the function of improving the thermal stability of the glass. On the other hand, when the content of B 2O3 is large, there is a possibility that the volatilization amount of the glass component increases at the time of glass melting. In addition, the high dispersion is hindered, and the devitrification resistance tends to be lowered. Therefore, the content of B 2O3 is preferably in the above range.
In the glass of embodiment 1 to 1, the content of Al 2O3 is preferably 20% or less, more preferably 10% or less, 5% or less, and 3% or less. The content of Al 2O3 may be 0%.
Al 2O3 is a glass component having an effect of improving the chemical durability and weather resistance of the glass, and can be considered as a network forming component. On the other hand, when the content of Al 2O3 is increased, the devitrification resistance of the glass is lowered. In addition, the glass transition temperature Tg tends to rise, and the thermal stability tends to decrease. From the viewpoint of avoiding such problems, the content of Al 2O3 is preferably in the above range.
In the glass of embodiment 1 to 1, the lower limit of the total content [ SiO 2+P2O5 ] of SiO 2 and P 2O5 is preferably 5%, and more preferably 10%, 15%, 17%, 19% and 21%. The upper limit of the total content [ SiO 2+P2O5 ] is preferably 50%, more preferably in the order of 40%, 37%, 35%, 33%, 31%, 29%, 27%.
By making the lower limit of the total content [ SiO 2+P2O5 ] of SiO 2 and P 2O5 satisfy the above condition, the reheat press formability can be improved. In addition, by making the upper limit of the total content [ SiO 2+P2O5 ] satisfy the above condition, the rise of the relative partial dispersion Pg, F can be suppressed, and the thermal stability of the glass can be maintained.
In the glass of embodiment 1 to 1, the lower limit of the total content [ SiO 2+P2O5+B2O3 ] of SiO 2、P2O5 and B 2O3 is preferably 5%, and more preferably 10%, 15%, 17%, 19% and 21%. The upper limit of the total content [ SiO 2+P2O5+B2O3 ] is preferably 50%, more preferably in the order of 40%, 37%, 35%, 33%, 31%, 29%, 27%.
SiO 2、P2O5 and B 2O3 are network forming components of glass, and mainly improve the thermal stability and devitrification resistance of the glass. Has the effects of increasing the viscosity of the molten glass and facilitating the formation of the molten glass. Therefore, the total content of SiO 2、P2O5 and B 2O3 is preferably in the above range.
In the glass of embodiment 1 to 1, the lower limit of the mass ratio [ P 2O5/(SiO2+P2O5) ] of the content of P 2O5 to the total content of SiO 2 and P 2O5 is preferably 0.001, and more preferably in the order of 0.005, 0.010, 0.020, 0.030, 0.040, 0.050, 0.060 and 0.070. The upper limit of the mass ratio [ P 2O5/(SiO2+P2O5) ] is preferably 0.910, and more preferably in the order of 0.700, 0.500, 0.300, 0.200, 0.150, 0.100.
When the mass ratio of the content of P 2O5 to the total content of SiO 2 and P 2O5 [ P 2O5/(SiO2+P2O5) ] is too low, the reheat press formability is deteriorated, and when it is too high, the relative partial dispersion Pg, F increases. Therefore, the mass ratio [ P 2O5/(SiO2+P2O5) ] is preferably in the above range.
In the glass of embodiment 1 to 1, the lower limit of the mass ratio [ P 2O5/(SiO2+P2O5+B2O3) ] of the content of P 2O5 to the total content of SiO 2、P2O5 and B 2O3 is preferably 0.001, and more preferably in the order of 0.005, 0.010, 0.020, 0.030.0.040, 0.050, 0.060 and 0.070. The upper limit of the mass ratio [ P 2O5/(SiO2+P2O5+B2O3) ] is preferably 0.910, and more preferably in the order of 0.700, 0.500, 0.300, 0.200, 0.150, 0.100.
In the glass of embodiment 1 to 1, the lower limit of the mass ratio [ SiO 2/(SiO2+P2O5+B2O3 ] of the content of SiO 2 to the total content of SiO 2、P2O5 and B 2O3 is preferably 0.100, and more preferably in the order of 0.300, 0.500, 0.600, 0.700 and 0.800. The upper limit of the mass ratio [ SiO 2/(SiO2+P2O5+B2O3) ] is preferably 1.000, and more preferably 0.999, 0.990, 0.980, 0.970, 0.960, 0.950, 0.940, and 0.930 are further in this order.
In the glass of embodiment 1 to 1, the lower limit of the content of ZrO 2 is preferably 0%, more preferably more than 0%, further more preferably in the order of 1%, 2%, 3%, 4%, 5%, 6%. The upper limit of the content of ZrO 2 is preferably 15%, more preferably in the order of 13%, 11%, 10%, 9%, 8%.
When the lower limit of the content of ZrO 2 is set to the above range, a glass having a high refractive index and high dispersibility can be obtained. In addition, when the upper limit of the content of ZrO 2 is set to the above range, the relative partial dispersion Pg and F can be reduced, and the occurrence of defects as optical elements can be suppressed, and the meltability and thermal stability of the glass can be maintained.
In the glass of embodiment 1 to 1, the lower limit of the content of TiO 2 is preferably 0%, more preferably in the order of 1%, 2%, 3% and 4%. The upper limit of the content of TiO 2 is preferably 20%, and more preferably 15%, 13%, 11%, 9%, 7%, 6%, and 5%.
TiO 2 is a component contributing to high dispersion, improves glass stability, and improves reheat press formability. On the other hand, when TiO 2 is excessively introduced, the relative partial dispersion Pg and F rise. Therefore, the content of TiO 2 is preferably in the above range. Note that TiO 2 and Nb 2O5 may be substituted for each other, and if substituted for Nb 2O5, the relative partial dispersions Pg, F may be reduced.
In the glass of embodiment 1 to 1, the lower limit of the total content [ Nb 2O5+TiO2 ] of Nb 2O5 and TiO 2 may be 10%, and further may be 20%, 25%, 30%, 35%, 40%, or 45%. The upper limit of the total content [ Nb 2O5+TiO2 ] is preferably 80%, more preferably in the order of 70%, 65%, 60%, 55%.
Nb 2O5 and TiO 2 are components contributing to high refractive index and high dispersion. Therefore, in order to obtain a glass having a desired abbe number vd, the total content of Nb 2O5 and TiO 2 is preferably in the above range.
In the glass of embodiment 1 to 1, the lower limit of the mass ratio [ P 2O5/Nb2O5 ] of the content of P 2O5 to the content of Nb 2O5 is preferably 0.001, and more preferably in the order of 0.005, 0.010, 0.015, 0.020, 0.025, 0.030, 0.035 and 0.040. The upper limit of the mass ratio [ P 2O5/Nb2O5 ] is preferably 0.125, and more preferably 0.120, 0.100, 0.090, 0.080, 0.070, 0.060, and 0.050 in this order.
Nb 2O5 is a component contributing to high dispersion, but tends to deteriorate the reheat press formability. On the other hand, P 2O5 can improve the reheat press formability. Therefore, from the viewpoint of the reheat press formability, the mass ratio [ P 2O5/Nb2O5 ] is preferably in the above range.
In the glass of embodiment 1 to 1, the lower limit of the mass ratio [ P 2O5/(Nb2O5+TiO2) ] of the content of P 2O5 to the total content of Nb 2O5 and TiO 2 is preferably 0.001, and more preferably in the order of 0.005, 0.010, 0.015, 0.020, 0.025, 0.030 and 0.035. The upper limit of the mass ratio [ P 2O5/(Nb2O5+TiO2) ] is preferably 0.125, and more preferably 0.120, 0.100, 0.090, 0.080, 0.070, 0.060, and 0.050 in this order.
Nb 2O5 and TiO 2 are components contributing to high dispersion, but tend to deteriorate the reheat press formability. On the other hand, P 2O5 can improve the reheat press formability. Therefore, the mass ratio [ P 2O5/(Nb2O5+TiO2) ] is preferably in the above range from the viewpoint of the reheat press formability.
In the glass of embodiment 1 to 1, the lower limit of the content of WO 3 is preferably 0%, and may be 1%, 3%, or 5%. The upper limit of the content of WO 3 is preferably 20%, more preferably in the order of 15%, 10% and 5%.
WO 3 is a component for improving the stability of glass and the reheat press formability. On the other hand, WO 3 increases the relative partial dispersion Pg, F and increases the specific gravity. In addition, the glass tends to be colored, and the transmittance is deteriorated. Therefore, the content of WO 3 is preferably in the above range.
In embodiment 1 to 1, the upper limit of the content of Bi 2O3 is preferably 20%, more preferably in the order of 10%, 5% and 3%. The lower limit of the content of Bi 2O3 is preferably 0%.
Bi 2O3 has an effect of improving the thermal stability of glass by properly containing it. On the other hand, if the content of Bi 2O3 is increased, the relative partial dispersion Pg, F increases, and the specific gravity also increases. In addition, the coloration of the glass increases. Therefore, the content of Bi 2O3 is preferably in the above range.
In the glass of embodiment 1-1, the upper limit of the total content [ Nb 2O5+TiO2+WO3+Bi2O3 ] of Nb 2O5、TiO2、WO3 and Bi 2O3 may be 80%, and further may be 70%, 60%, or 55%. The lower limit of the total content [ Nb 2O5+TiO2+WO3+Bi2O3 ] may be set to 10%, or may be set to 20%, 25%, 30%, 35%, 40%, or 45%.
TiO 2、WO3 and Bi 2O3 are components contributing to an increase in refractive index and a high dispersion together with Nb 2O5. Therefore, the total content [ Nb 2O5+TiO2+WO3+Bi2O3 ] is preferably in the above range.
In the glass of embodiment 1 to 1, the upper limit of the mass ratio [ Nb 2O5/(Nb2O5+TiO2+WO3+Bi2O3) ] of the content of Nb 2O5 to the total content of Nb 2O5、TiO2、WO3 and Bi 2O3 is preferably 1.000 from the viewpoint of obtaining desired relative partial dispersion Pg, F, but may be set to 0.990, 0.970, 0.950, 0.930, or 0.910. The lower limit of the mass ratio [ Nb 2O5/(Nb2O5+TiO2+WO3+Bi2O3) ] is preferably 0.100, more preferably in the order of 0.200, 0.300, 0.400, 0.500, 0.600, 0.6110, 0.700, 0.800, 0.855.
In the glass of embodiment 1 to 1, the upper limit of the mass ratio [ ZrO 2/(Nb2O5+TiO2+WO3+Bi2O3) ] of the content of ZrO 2 to the total content of Nb 2O5、TiO2、WO3 and Bi 2O3 is preferably 1.000, and more preferably in the order of 0.800, 0.600, 0.400, 0.300, 0.250 and 0.200. The lower limit of the mass ratio [ ZrO 2/(Nb2O5+TiO2+WO3+Bi2O3) ] is preferably 0, and more preferably in the order of 0.001, 0.005, 0.007, 0.010.
In the glass of embodiment 1 to 1, the upper limit of the mass ratio [(SiO2+P2O5+B2O3)/(Nb2O5+TiO2+WO3+Bi2O3)] of the total content of SiO 2、P2O5 and B 2O3 to the total content of Nb 2O5、TiO2、WO3 and Bi 2O3 may be 5.000, or may be 3.000, 2.000, 1.500, 1.000, or 0.900. The lower limit of the mass ratio [(SiO2+P2O5+B2O3)/(Nb2O5+TiO2+WO3+Bi2O3)] may be 0.013, or may be 0.100, 0.200, 0.300, 0.350, or 0.400.
By setting the mass ratio [(SiO2+P2O5+B2O3)/(Nb2O5+TiO2+WO3+Bi2O3)] to the above range, the abbe number vd and the relative partial dispersion Pg, F can be controlled.
In the glass of embodiment 1-1, the upper limit of the content of Li 2 O may be set to 10%, and further may be set to 9%, 7%, 5%, or 3%. The lower limit of the content of Li 2 O may be set to 0%, or further, may be set to 0.5%, 1.0%, 1.5%, 2.0%, 3.0%, or 4.0%.
In the glass of embodiment 1 to 1, the upper limit of the Na 2 O content may be 30%, and further may be 20%, 15%, 10%, 8%, 6%, 5%, or 4%. The lower limit of the Na 2 O content may be 0%, or may be 0.5%, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 7.0%, 9.0%, 11.0%, or 12.0%.
The upper limit of the content of K 2 O in the glass according to embodiment 1-1 may be 30%, and further may be 25%, 20%, 17%, 15%, 13%, 11%, 9%, 7%, 5%, 3%, or 1%. The lower limit of the content of K 2 O may be 0%, or may be 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, 3.0%, 5.0%, 7.0%, 9.0%, 11.0%, or 13.0%.
Both Li 2O、Na2 O and K 2 O have the effect of lowering the liquid phase temperature and improving the thermal stability of the glass, but when the content of these is increased, the chemical durability and weather resistance are reduced. Therefore, the respective contents of Li 2O、Na2 O and K 2 O are preferably in the above ranges.
In the glass of embodiment 1 to 1, the upper limit of the mass ratio [ Li 2O/(Li2O+Na2O+K2 O) ] of the content of Li 2 O to the total content of Li 2O、Na2 O and K 2 O may be set to 1.000, and further, may be set to 0.700, 0.500, 0.300, 0.200, 0.100, or 0.000. The lower limit of the mass ratio [ Li 2O/(Li2O+Na2O+K2 O) ] may be set to 0.000, and further may be set to 0.100, 0.200, 0.300, 0.500, or 0.700.
In the glass of embodiment 1 to 1, the upper limit of the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] of the Na 2 O content to the total content of Li 2O、Na2 O and K 2 O may be set to 1.000, and further, may be set to 0.970, 0.960, 0.950, 0.900, 0.850, 0.800, 0.750, 0.700, 0.500, 0.300, 0.200, 0.100, or 0.000. The lower limit of the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] may be set to 0.000, and further may be set to 0.100, 0.200, 0.300, 0.330, 0.340, 0.350, 0.360, 0.370, 0.450, 0.460, 0.470, 0.480, 0.490, 0.500, or 0.700.
In the glass of embodiment 1 to 1, the upper limit of the mass ratio [ K 2O/(Li2O+Na2O+K2 O) ] of the content of K 2 O to the total content of Li 2O、Na2 O and K 2 O may be set to 1.000, and further, may be set to 0.700, 0.500, 0.300, 0.200, 0.100, or 0.000. The lower limit of the mass ratio [ K 2O/(Li2O+Na2O+K2 O) ] may be set to 0.000, and further may also be set to 0.100, 0.200, 0.300, 0.500, or 0.700.
In the glass of embodiment 1 to 1, the upper limit of the content of Cs 2 O is preferably 10%, more preferably in the order of 5%, 3% and 1%. The lower limit of the content of Cs 2 O is preferably 0%.
Cs 2 O has an effect of improving the thermal stability of the glass, but when the content thereof is increased, chemical durability and weather resistance are reduced. Therefore, each content of Cs 2 O is preferably in the above range.
In the glass of embodiment 1 to 1, the lower limit of the total content of alkali metal oxides is preferably 1%, more preferably in the order of 3%, 5%, 7%, 9%, 11%, 13% and 15%. The upper limit of the total content of alkali metal oxides is preferably 40%, more preferably in the order of 35%, 30%, 25%, and 20%.
The alkali metal oxide is preferably 1 or more oxides selected from Li 2O、Na2O、K2 O and Cs 2 O. In addition, the alkali metals may be replaced respectively.
By setting the lower limit of the total content of alkali metal oxides to the above range, the meltability and thermal stability of the glass can be improved and the liquid phase temperature can be reduced. In addition, by making the upper limit of the total content of alkali metal oxides satisfy the above range, occurrence of defects as optical elements can be suppressed.
In the glass of embodiment 1 to 1, the lower limit of the total content [ Li 2O+Na2O+K2 O ] of Li 2O、Na2 O and K 2 O is preferably 1%, more preferably more than 1.1%, and further more preferably in the order of 3%, 5%, 7%, 9%, 10%, 11%, 13% and 15%. The upper limit of the total content [ Li 2O+Na2O+K2 O ] is preferably 40%, and more preferably 35%, 30%, 25%, 22.0%, 21.7%, 21.4%, 21.1%, and 20% are further in this order.
Further, in the glass of embodiment 1 to 1, the upper limit of the mass ratio [P2O5/(Li2O+Na2O+K2O+Cs2O+Nb2O5+TiO2+WO3+Bi2O3)] of the content of P 2O5 to the total content of Li 2O、Na2O、K2O、Cs2O、Nb2O5、TiO2、WO3 and Bi 2O3 is preferably 1.000, and more preferably in the order of 0.500, 0.300, and 0.100. The lower limit of the mass ratio [P2O5/(Li2O+Na2O+K2O+Cs2O+Nb2O5+TiO2+WO3+Bi2O3)] is preferably 0.001, and more preferably 0.003, 0.005, 0.007, 0.009, 0.011, 0.013, 0.015, 0.017, 0.019 and 0.021 are further preferable.
By properly introducing Li 2O、Na2O、K2O、Cs2O、Nb2O5、TiO2、WO3 and Bi 2O3 as glass components, a desired Abbe number vd and relative partial dispersion Pg, F can be obtained. However, if these components are introduced into silicate glass, there is a risk that the reheat press formability is deteriorated. On the other hand, P 2O5 is a component for improving the reheat press formability. Therefore, if the mass ratio [P2O5/(Li2O+Na2O+K2O+Cs2O+Nb2O5+TiO2+WO3+Bi2O3)] is too high, there is a possibility that the stability of the glass becomes poor and the relative partial dispersion Pg, F becomes high, and if it is too low, there is a possibility that the reheat press formability becomes poor. Therefore, the mass ratio [P2O5/(Li2O+Na2O+K2O+Cs2O+Nb2O5+TiO2+WO3+Bi2O3)] is preferably set within the above range.
In the glass of embodiment 1 to 1, the upper limit of the mass ratio [(Li2O+Na2O+K2O+Cs2O)/(SiO2+P2O5+B2O3)] of the total content of Li 2O、Na2O、K2 O and Cs 2 O to the total content of SiO 2、P2O5 and B 2O3 is preferably 5.000, and more preferably 3.000, 2.000, 1.500, 1.300, 1.100, 1.000, and 0.900. The lower limit of the mass ratio [(Li2O+Na2O+K2O+Cs2O)/(SiO2+P2O5+B2O3)] is preferably 0.020, and more preferably in the order of 0.100, 0.200, 0.300, 0.400, and 0.500.
If the mass ratio [(Li2O+Na2O+K2O+Cs2O)/(SiO2+P2O5+B2O3)] is too low, there is a possibility that the melting property is deteriorated and the relative partial dispersion Pg and F are increased, and if it is too high, there is a possibility that the glass stability is lowered and the reheat press formability is deteriorated.
In the glass of embodiment 1 to 1, the upper limit of the mass ratio [(Li2O+Na2O+K2O+Cs2O)/(Nb2O5+TiO2+WO3+Bi2O3)] of the total content of Li 2O、Na2O、K2 O and Cs 2 O to the total content of Nb 2O5、TiO2、WO3 and Bi 2O3 is preferably 4.000, and more preferably 3.000, 2.000, 1.000, 0.900, 0.700, and 0.500 in this order. The lower limit of the mass ratio [(Li2O+Na2O+K2O+Cs2O)/(Nb2O5+TiO2+WO3+Bi2O3)] is preferably 0.015, and more preferably 0.050, 0.100, 0.150, 0.200, and 0.250.
If the mass ratio [(Li2O+Na2O+K2O+Cs2O)/(Nb2O5+TiO2+WO3+Bi2O3)] is too low, there is a possibility that the relative partial dispersion Pg, F increases and the transmittance deteriorates, and if it is too high, there is a possibility that the glass stability decreases and the reheat press formability deteriorates.
In the glass of embodiment 1 to 1, the upper limit of the MgO content is preferably 20%, more preferably in the order of 10%, 5% and 3%. The lower limit of the MgO content is preferably 0%.
In the glass of embodiment 1 to 1, the upper limit of the CaO content is preferably 20%, more preferably in the order of 10%, 5% and 3%. The lower limit of the CaO content is preferably 0%.
In the glass of embodiment 1 to 1, the upper limit of the SrO content is preferably 20%, more preferably in the order of 10%, 5% and 3%. The lower limit of the SrO content is preferably 0%.
In the glass of embodiment 1 to 1, the upper limit of the content of BaO is preferably 20%, more preferably in the order of 10%, 5% and 3%. The lower limit of the content of BaO is preferably 0%.
MgO, caO, srO, baO are glass components having an effect of improving the thermal stability and devitrification resistance of the glass. However, when the content of these glass components increases, the specific gravity increases, high dispersibility is impaired, and the thermal stability and devitrification resistance of the glass decrease. Therefore, the respective contents of these glass components are preferably within the above ranges.
In the glass of embodiment 1 to 1, the upper limit of the ZnO content is preferably 20%, more preferably in the order of 10%, 5% and 3%. The lower limit of the ZnO content is preferably 0%.
ZnO is a glass component having an effect of improving the thermal stability of glass. However, if the content of ZnO is too large, the specific gravity increases. Therefore, the content of ZnO is preferably in the above range from the viewpoint of improving the thermal stability of the glass and maintaining desired optical characteristics.
In the glass of embodiment 1 to 1, the upper limit of the total content of MgO and CaO [ MgO+CaO ] is preferably 20%, more preferably in the order of 10%, 5% and 3%. The lower limit of the total content [ MgO+CaO ] is preferably 0%. The total content [ MgO+CaO ] may be 0%. The total content [ MgO+CaO ] is preferably within the above range from the viewpoint of not impeding the high dispersibility and maintaining the thermal stability.
In the glass of embodiment 1 to 1, the upper limit of the total content [ MgO+CaO+SrO+BaO+ZnO ] of MgO, caO, srO, baO and ZnO is preferably 20%, more preferably in the order of 10%, 5% and 3%. The lower limit of the total content [ MgO+CaO+SrO+BaO+ZnO ] is preferably 0%. The total content [ MgO+CaO+SrO+BaO+ZnO ] may be 0%. The total content [ MgO+CaO+SrO+BaO+ZnO ] is preferably in the above range from the viewpoint of suppressing an increase in specific gravity and not inhibiting high dispersion and maintaining thermal stability.
In the glass of embodiment 1 to 1, the upper limit of the mass ratio [ (mgo+cao+sro+bao+zno)/(Li 2O+Na2O+K2O+Cs2 O) ] of the total content of MgO, caO, srO, baO and ZnO to the total content of Li 2O、Na2O、K2 O and Cs 2 O is preferably 20.000, more preferably in the order of 10.000, 5.000, 3.000, 1.000, and 0.500. The lower limit of the mass ratio [ (MgO+CaO+SrO+BaO+ZnO)/(Li 2O+Na2O+K2O+Cs2 O) ] is preferably 0.000. The lower limit of the mass ratio [ (MgO+CaO+SrO+BaO+ZnO)/(Li 2O+Na2O+K2O+Cs2 O) ] may also be 0.000.
In the glass of embodiment 1 to 1, the upper limit of the content of La 2O3 is preferably 20%, more preferably in the order of 10%, 5% and 3%. The lower limit of the content of La 2O3 is preferably 0%.
When the content of La 2O3 is increased, the specific gravity is increased and the thermal stability of the glass is lowered. Therefore, the content of La 2O3 is preferably in the above range from the viewpoint of suppressing an increase in specific gravity and a decrease in thermal stability of the glass.
In the glass of embodiment 1 to 1, the upper limit of the content of Y 2O3 is preferably 20%, more preferably in the order of 10%, 5% and 3%. The lower limit of the content of Y 2O3 is preferably 0%.
When the content of Y 2O3 is too large, the thermal stability of the glass is lowered, and the glass is easily devitrified during production. Therefore, the content of Y 2O3 is preferably in the above range from the viewpoint of suppressing the decrease in the thermal stability of the glass.
In the glass of embodiment 1 to 1, the upper limit of the content of Ta 2O5 is preferably 20%, more preferably in the order of 10%, 5% and 3%. The lower limit of the content of Ta 2O5 is preferably 0%.
Ta 2O5 is a glass component having an effect of improving the thermal stability of glass, and is a component that reduces Pg and F in the Nb 2O5、TiO2、WO3、Bi2O3 component. On the other hand, when the content of Ta 2O5 is increased, the thermal stability of the glass is lowered, and when the glass is melted, melting residues of the glass raw material are likely to occur. Further, the specific gravity increases. Therefore, the content of Ta 2O5 is preferably in the above range.
In the glass of embodiment 1 to 1, the upper limit of the mass ratio [Ta2O5/(Ta2O5+Nb2O5+TiO2+WO3+Bi2O3)] of the content of Ta 2O5 to the total content of Ta 2O5、Nb2O5、TiO2、WO3 and Bi 2O3 is preferably 0.900, and more preferably in the order of 0.700, 0.500, 0.300, 0.100, 0.050, and 0.010. The lower limit is 0.000.
If the mass ratio [Ta2O5/(Ta2O5+Nb2O5+TiO2+WO3+Bi2O3)] is too high, there are risks of an increase in specific gravity and an increase in cost.
In the glass of embodiment 1 to 1, the content of Sc 2O3 is preferably 2% or less. The lower limit of the content of Sc 2O3 is preferably 0%.
In the glass of embodiment 1-1, the content of HfO 2 is preferably 2% or less. The lower limit of the content of HfO 2 is preferably 0%.
Sc 2O3、HfO2 has an effect of improving the high dispersibility of the glass, but is an expensive component. Therefore, each content of Sc 2O3、HfO2 is preferably within the above range.
In the glass of embodiment 1 to 1, the content of Lu 2O3 is preferably 2% or less. The lower limit of the content of Lu 2O3 is preferably 0%.
Lu 2O3 has an effect of improving the high dispersibility of the glass, but is also a glass component that increases the specific gravity of the glass because of its large molecular weight. Therefore, the content of Lu 2O3 is preferably in the above range.
In the glass of embodiment 1 to 1, the content of GeO 2 is preferably 2% or less. The lower limit of the content of GeO 2 is preferably 0%.
GeO 2 has an effect of improving high dispersibility of glass, but is a very expensive component among commonly used glass components. Therefore, the content of GeO 2 is preferably in the above range from the viewpoint of reducing the manufacturing cost of the glass.
In the glass of embodiment 1 to 1, the content of Gd 2O3 is preferably 2% or less. The lower limit of the content of Gd 2O3 is preferably 0%.
When the content of Gd 2O3 is too large, the heat stability of the glass is lowered. If the content of Gd 2O3 is too large, the specific gravity of the glass increases, which is not preferable. Therefore, the content of Gd 2O3 is preferably in the above range from the viewpoint of keeping the thermal stability of the glass well and suppressing the increase of specific gravity.
In the glass of embodiment 1-1, the content of Yb 2O3 is preferably 2% or less. The lower limit of the Yb 2O3 content is preferably 0%.
Yb 2O3 has a larger molecular weight than La 2O3、Gd2O3、Y2O3, and thus, increases the specific gravity of the glass. When the specific gravity of the glass increases, the mass of the optical element increases. For example, when a lens having a large mass is assembled to an auto-focus type imaging lens, power required for driving the lens increases during auto-focus, and battery consumption increases. Therefore, it is preferable to reduce the content of Yb 2O3 to suppress an increase in specific gravity of the glass.
In addition, when the content of Yb 2O3 is too large, the thermal stability of the glass is lowered. The content of Yb 2O3 is preferably in the above range from the viewpoint of preventing a decrease in the thermal stability of the glass and suppressing an increase in specific gravity.
The glass of embodiment 1-1 is preferably composed mainly of the above-mentioned glass components, that is, SiO2、P2O5、B2O3、Al2O3、TiO2、Nb2O5、WO3、Bi2O3、Li2O、Na2O、K2O、Cs2O、MgO、CaO、SrO、BaO、ZnO、ZrO2、Ta2O5、Sc2O3、HfO2、Lu2O3、GeO2、La2O3、Gd2O3、Y2O3 and Yb 2O3, and the total content of the above-mentioned glass components is preferably more than 95%, more preferably more than 98%, still more preferably more than 99%, still more preferably more than 99.5%.
The glass of embodiment 1 to 1 is preferably composed of the above glass components, but may contain other components within a range that does not interfere with the operation and effect of embodiment 1. In the invention 1, the inclusion of unavoidable impurities is not excluded.
(Glass characteristics)
< Refractive index nd >)
In one example of the glass of embodiment 1 to 1, the lower limit of the refractive index nd may be 1.55, and further may be 1.60, 1.65, 1.70, 1.75, or 1.80. The upper limit of the refractive index nd may be 1.95, or may be 1.90, 1.85, 1.80, or 1.75. The refractive index can be controlled by adjusting the content of Nb 2O5、TiO2、WO3 and Bi 2O3 as glass components contributing to the higher refractive index.
< Specific gravity of glass >
The glass of embodiment 1-1 is a high refractive index and high dispersion glass, but has a low specific gravity. In general, if the specific gravity of glass can be reduced, the weight of the lens can be reduced. As a result, the power consumption for the autofocus drive of the camera lens on which the lens is mounted can be reduced. On the other hand, if the specific gravity is excessively reduced, it may result in a decrease in thermal stability.
Therefore, in the example of the glass according to embodiment 1-1, the preferred range of the specific gravity is 4.5 or less, and more preferably 4.3 or less, 4.1 or less, 4.0 or less, 3.9 or less, 3.8 or less, 3.7 or less, and 3.6 or less. The specific gravity can be controlled by adjusting the mass ratio [ P 2O5/(SiO2+P2O5+B2O3) ], the mass ratio [ (MgO+CaO+SrO+BaO+ZnO)/(Li 2O+Na2O+K2O+Cs2 O) ], the mass ratio [(Li2O+Na2O+K2O+Cs2O)/(Nb2O5+TiO2+WO3+Bi2O3)]、: [(SiO2+P2O5+B2O3)/(Nb2O5+TiO2+WO3+Bi2O3)]、: [Ta2O5/(Ta2O5+Nb2O5+TiO2+WO3+Bi2O3)]、:Nb 2O5/(Nb2O5+TiO2+WO3+Bi2O3 ], and the mass ratio [ ZrO 2/(Nb2O5+TiO2+WO3+Bi2O3 ].
< Glass transition temperature Tg >)
In one example of the glass of embodiment 1 to 1, the upper limit of the glass transition temperature Tg is preferably 700℃and more preferably 670℃and 650℃and 630℃and 610℃and 590 ℃. The lower limit of the glass transition temperature Tg is preferably 450℃and more preferably 500℃and 510℃and 530℃and 550℃in this order. The glass transition temperature Tg can be controlled by adjusting the mass ratio [ (mgo+cao+sro+bao+zno)/(Li 2O+Na2O+K2O+Cs2 O) ], the mass ratio [(Li2O+Na2O+K2O+Cs2O)/(Nb2O5+TiO2+WO3+Bi2O3)]、, the mass ratio [(SiO2+P2O5+B2O3)/(Nb2O5+TiO2+WO3+Bi2O3)]、, the mass ratio Nb 2O5/(Nb2O5+TiO2+WO3+Bi2O3 ], and the mass ratio ZrO 2/(Nb2O5+TiO2+WO3+Bi2O3 ].
By satisfying the above condition as the upper limit of the glass transition temperature Tg, the rise of the molding temperature and the annealing temperature at the time of reheating the glass can be suppressed, and the damage of heat to the equipment for reheating molding and the annealing equipment can be reduced.
By satisfying the above conditions, the lower limit of the glass transition temperature Tg can easily maintain a desired abbe number and refractive index, and can also favorably maintain the reheat press formability and the thermal stability of the glass.
Transmittance >, transmittance
The optical glass of embodiment 1-1 is an optical glass having very little coloration. The optical glass is suitable for use as a material for an optical element for imaging such as a camera lens or an optical element for projection such as a projector.
The coloring degree of the optical glass is generally represented by λ70, λ5, or the like. For a glass sample having a thickness of 10.0 mm.+ -. 0.1mm, the spectral transmittance was measured in the wavelength range of 200 to 700nm, the wavelength at which the external transmittance reached 70% was represented by λ70, and the wavelength at which the external transmittance reached 5% was represented by λ5.
In one example of the glass of embodiment 1-1, λ70 is preferably 500nm or less, more preferably 470nm or less, 450nm or less, 430nm or less, 410nm or less, and 405nm or less. Also, λ5 is preferably 390nm or less, more preferably 380nm or less, 370nm or less, and 360nm or less. λ70, λ5 can be controlled by adjusting the mass ratio [(Li2O+Na2O+K2O+Cs2O)/(Nb2O5+TiO2+WO3+Bi2O3)]、 to [(SiO2+P2O5+B2O3)/(Nb2O5+TiO2+WO3+Bi2O3)]、 to [Ta2O5/(Ta2O5+Nb2O5+TiO2+WO3+Bi2O3)]、 [ Nb 2O5/(Nb2O5+TiO2+WO3+Bi2O3) ], and the mass ratio [ ZrO 2/(Nb2O5+TiO2+WO3+Bi2O3 ].
< Processability >
The glass of embodiment 1-1 can have improved hot-press formability (workability) by containing P 2O5. In the hot-press, the glass is heated, and the softened state (viscosity) of the glass is controlled. The glass of embodiment 1-1 is less likely to cause internal defects and devitrification even when subjected to hot-pressing over a wide temperature range, and therefore, the softened state (viscosity) of the glass can be easily adjusted, and the workability is excellent.
The heating temperature at the time of the hot-press is, for example, a temperature at which glass is softened and deformed. Specifically, the heating temperature is assumed to be about 50 ℃ higher than the glass transition temperature Tg in the case of low, and is assumed to be about 200 to 300 ℃ higher than the glass transition temperature Tg in the case of high.
When the heating temperature at the time of the hot-press is low, that is, when the glass is heated at a temperature about 50 ℃ higher than the glass transition temperature Tg, the inside of the glass is less likely to undergo phase separation, and even in the glass containing no P 2O5, the occurrence of internal defects and devitrification can be suppressed.
However, when the heating temperature at the time of the reheat pressing is low, a high pressure needs to be applied at the time of press forming. As a result, there is a high possibility that cracks occur in the glass or the glass is cracked during the cooling of the pressed glass molded article (e.g., lens blank). Therefore, when the heating temperature at the time of the reheat pressing is low, the yield of production is liable to decrease, and the shape of the press-formable glass shaped article is liable to be limited.
On the other hand, when the heating temperature at the time of hot-pressing is high, that is, when the heating is performed at a temperature higher than the glass transition temperature Tg by about 200 to 300 ℃, phase separation is likely to occur in the glass without P 2O5, and internal defects and devitrification are likely to occur in the glass.
However, when the heating temperature at the time of the hot-press is high, the press molding does not require a high pressure, and the glass molded product is less likely to crack. Therefore, the reduction in yield can be suppressed, and the shape of the glass molded product is not easily restricted.
The glass of embodiment 1-1 contains P 2O5, and thus internal defects are less likely to occur even when subjected to reheat pressing at an arbitrary assumed heating temperature. In particular, even when the hot-press is performed at a high temperature, there are problems that internal defects and devitrification are less likely to occur, that the reduction in yield and the limitation in shape are less likely to occur.
In one example of the glass of embodiment 1 to 1, the upper limit of the number of internal defects generated when the glass is heat-treated at a temperature at which the glass is softened or deformed is preferably 1000 pieces/g, and more preferably 900 pieces/g, 700 pieces/g, 500 pieces/g, 300 pieces/g, 100 pieces/g, 70 pieces/g, 50 pieces/g, 40 pieces/g, 35 pieces/g, 30 pieces/g, 25 pieces/g, 20 pieces/g, 15 pieces/g, 13 pieces/g, 10 pieces/g, 9 pieces/g, 7 pieces/g, 5 pieces/g, 3 pieces/g, 2 pieces/g, 1 piece/g, and 0 piece/g. The upper limit of the allowable number of internal defects is different depending on the use of the glass. The internal defects are set to a size in the range of 1 to 300. Mu.m.
In addition, the glass of embodiment 1-1 has fewer internal defects than the glass containing no P 2O5 when heat-treated at a temperature at which the glass softens and deforms. When the number of internal defects of the glass (including P 2O5) of embodiment 1-1 is Ip [ number/g ], and the number of internal defects of the glass having the same composition except for P 2O5 and containing no P 2O5 is I [ number/g ], Δi [ number/g ] =i—ip is preferably 1.0 or more, and more preferably in the order of 2 or more, 5 or more, 7 or more, 10 or more, 20 or more, 50 or more, 100 or more, 1000 or more, 10000 or more, 100000 or more. The internal defects are set to a size in the range of 1 to 300. Mu.m.
(Production of optical glass)
The glass according to the embodiment of the invention 1 may be produced by a known glass production method by blending glass raw materials so as to have the above-described predetermined composition and using the blended glass raw materials. For example, a plurality of compounds are prepared and mixed thoroughly to prepare a batch material, and the batch material is put into a quartz crucible or a platinum crucible to be subjected to coarse melting (rough melt). And (3) rapidly cooling and crushing the melt obtained by the coarse melting to prepare cullet. Further, the crushed glass is put into a platinum crucible to be heated and remelted (remelt) to prepare molten glass, and after the molten glass is clarified and homogenized, the molten glass is formed and slowly cooled to obtain the optical glass. The molten glass may be formed by a known method by slow cooling.
The compound used in preparing the batch raw material is not particularly limited as long as a desired glass component can be introduced into the glass and the desired content thereof can be obtained, and examples of the compound include oxides, carbonates, nitrates, hydroxides, fluorides, and the like.
As the optical glass according to embodiment 1 of the present invention, the glass according to embodiment 1 of the present invention can be used as it is.
(Production of optical element etc.)
When an optical element is produced using the optical glass according to embodiment 1 of the present invention, a known method may be used. For example, in the production of the optical glass, a glass material formed of the optical glass of the present invention is produced by molding molten glass into a plate shape. The obtained glass material is cut, ground and polished appropriately to produce pieces of a size and shape suitable for press molding. The chips were heated and softened, and press-formed (hot-pressed) by a known method to produce an optical element blank having a shape similar to that of an optical element. The optical element blank is annealed, and grinding is performed by a known method to produce an optical element.
Depending on the purpose of use, an antireflection film, a total reflection film, or the like may be coated on the optical functional surface of the manufactured optical element.
According to an embodiment of the invention of claim 1, an optical element formed of the above optical glass can be provided. Examples of the type of the optical element include lenses such as spherical lenses and aspherical lenses, prisms, and diffraction gratings. Examples of the lens shape include various shapes such as a biconvex lens, a plano-convex lens, a biconcave lens, a plano-concave lens, a convex meniscus lens, and a concave meniscus lens. The optical element can be manufactured by a method including a step of processing a glass molded body formed of the optical glass. Examples of the processing include cutting, rough grinding, finish grinding, and polishing. When such processing is performed, breakage can be reduced by using the glass, and a high-quality optical element can be stably provided.
1 St to 2 nd embodiment
Hereinafter, as embodiment 1 to 2, the glass of invention 1 will be described based on the mass ratio of the glass components. The actions and effects of the respective glass components in embodiment 1-2 are the same as those of the respective glass components in embodiment 1-1. Therefore, the description of embodiment 1-1 will be omitted as appropriate.
The glass of embodiment 1-2 is a silicate glass having an Abbe number vd of 20 to 35,
Contains P 2O5 and Nb 2O5,
And the mass ratio of the content of Nb 2O5 to the total content of Nb 2O5、TiO2、WO3 and Bi 2O3 [ Nb 2O5/(Nb2O5+TiO2+WO3+Bi2O3) ] is larger than 0.6110.
The glass of embodiments 1 to 2 is a silicate glass mainly containing SiO 2 as a network forming component of the glass. The content of SiO 2 is preferably more than 0%, and the lower limit thereof is more preferably in the order of 1%, 5%, 10%, 15, 20%. The upper limit of the content of SiO 2 is preferably 60%, more preferably in the order of 50%, 40%, 39%, 38%, 37%, 36%, 35%.
SiO 2 is used as a network forming component of glass, and has the functions of improving the thermal stability, chemical durability and weather resistance of the glass, increasing the viscosity of the molten glass and facilitating the forming of the molten glass. On the other hand, when the content of SiO 2 is large, the devitrification resistance of the glass tends to be low, and Pg and F are increased. Therefore, the content of SiO 2 is preferably set to the above range.
The lower limit of the content of P 2O5.P2O5 in the glass of embodiment 1-2 is preferably 0.1%, more preferably in the order of 0.3%, 0.5%, 0.7%, 0.9%, 1.1%, 1.3%, 1.5%, 1.7%, 1.9%. The upper limit of the content of P 2O5 is preferably 10%, more preferably 7%, 5% and 3%.
By making the lower limit of the content of P 2O5 satisfy the above range, the reheat press formability can be improved. In addition, by setting the upper limit of the content of P 2O5 to the above range, the thermal stability of the glass can be maintained, and the reheat press formability can be improved.
The lower limit of the content of Nb 2O5.Nb2O5 in the glass of embodiments 1 to 2 may be 1%, and further may be 10%, 20%, 24%, 25%, 30%, 35%, 40%, or 43%. The upper limit of the content of Nb 2O5 is preferably 80%, more preferably in the order of 60%, 55%, 50%, 45%.
Nb 2O5 is a component contributing to high dispersion. Therefore, by setting the lower limit of the content of Nb 2O5 to the above range, a glass with high refractive index and high dispersibility can be obtained. Nb 2O5 is also a glass component for improving the thermal stability and chemical durability of the glass. Therefore, when the upper limit of the content of Nb 2O5 is set to the above range, the thermal stability and chemical durability of the glass can be maintained well, and the occurrence of defects as optical elements can be suppressed.
In the glass of embodiment 1-2, abbe number vd is 20 to 35. The Abbe number vd may be 22 to 33, 23 to 31, 23 to 27, or 23 to 26.
By setting the Abbe number vd to the above range, a glass with high dispersibility can be obtained.
The Abbe number vd can be controlled by adjusting the content of Nb 2O5、TiO2、WO3 and Bi 2O3 as glass components contributing to high dispersion.
In the glass of embodiments 1 to 2, the mass ratio [ Nb 2O5/(Nb2O5+TiO2+WO3+Bi2O3) ] of the content of Nb 2O5 to the total content of Nb 2O5、TiO2、WO3 and Bi 2O3 is larger than 0.6110. The lower limit of the mass ratio [ Nb 2O5/(Nb2O5+TiO2+WO3+Bi2O3) ] is preferably 0.700, more preferably in the order of 0.750, 0.800, 0.850. The upper limit of the content of the mass ratio [ Nb 2O5/(Nb2O5+TiO2+WO3+Bi2O3) ] is preferably 1.000, and more preferably in the order of 0.990, 0.970, 0.950, 0.930, and 0.910.
By setting the mass ratio [ Nb 2O5/(Nb2O5+TiO2+WO3+Bi2O3) ] within the above range, an optical glass suitable for secondary chromatic aberration correction can be provided.
The glass composition in embodiment 1-2 may be the same as that in embodiment 1-1. The glass characteristics, the production of optical glass, the production of optical elements, and the like in embodiment 1-2 may be the same as those in embodiment 1-1.
(Other embodiments)
Hereinafter, as the glass according to another embodiment of the invention 1, embodiment a, embodiment B, and embodiment C will be described.
The glasses of embodiment A, embodiment B and embodiment C shown below also have preferable characteristics different from those of the glasses of embodiments 1-1 and 1-2.
Therefore, when the characteristics of the glasses of embodiment a, embodiment B, and embodiment C are different from those of the glasses of embodiments 1-1 and 1-2, the preferable ranges of the characteristics of the glasses of embodiment a, embodiment B, and embodiment C are applicable to the ranges described below.
Embodiment A
The glass of embodiment a is characterized in that,
The Abbe number vd is 26.0 or more,
The mass ratio [ B 2O3/SiO2 ] of the content of B 2O3 to the content of SiO 2 is 0.800 or less,
The mass ratio [ (SiO 2+B2O3)/(Nb2O5+TiO2) ] of the total content of SiO 2 and B 2O3 to the total content of Nb 2O5 and TiO 2 is 0.950 or less,
The mass ratio of the total content of MgO, caO, srO, baO and ZnO to the total content of Li 2O、Na2 O and K 2 O [ (MgO+CaO+SrO+BaO+ZnO)/(Li 2O+Na2O+K2 O) ] is 0.480 or less,
The mass ratio of the content of TiO 2 to the content of Nb 2O5 [ TiO 2/Nb2O5 ] is 0.340 or less,
The mass ratio [ (Li 2O+Na2O+K2O)/(TiO2+Nb2O5) ] of the total content of Li 2O、Na2 O and K 2 O to the total content of TiO 2 and Nb 2O5 is 0.700 or less,
SiO2、B2O3、P2O5、Al2O3、Li2O、Na2O、K2O、MgO、CaO、ZnO、La2O3、Y2O3、Gd2O3、ZrO2、TiO2 And the total content of Nb 2O5 is more than 96.0 percent,
The contents of PbO, cdO and As 2O3 are respectively below 0.01%.
The glass of embodiment a has an abbe number vd of 26.0 or more, a relatively small specific gravity, and small relative partial dispersion Pg, F with respect to the abbe number vd.
In the glass of embodiment a, the upper limit of the mass ratio [ B 2O3/SiO2 ] of the content of B 2O3 to the content of SiO 2 may be set to 0.800, and more preferably, the order of 0.700, 0.600, 0.550, 0.500, 0.450, 0.350, 0.300, 0.250, and 0.200 may be set. The mass ratio [ B 2O3/SiO2 ] may also be 0.
By setting the mass ratio [ B 2O3/SiO2 ] to the above range, an increase in specific gravity and coloring of glass can be suppressed.
In the glass of embodiment a, the upper limit of the mass ratio [ (SiO 2+B2O3)/(Nb2O5+TiO2) ] of the total content of SiO 2 and B 2O3 to the total content of Nb 2O5 and TiO 2 may be set to 0.950, and more preferably, the order of 0.930, 0.920, 0.910, 0.900, 0.890, 0.880, 0.870, 0.860, 0.850, 0.840, 0.830, 0.820, 0.810, 0.800, 0.790, and 0.780 is more preferable. The lower limit of the mass ratio [ (SiO 2+B2O3)/(Nb2O5+TiO2) ] is preferably 0.300, and more preferably 0.350, 0.400, 0.450, 0.500, 0.550, 0.600, 0.630, 0.650, 0.670, 0.680, and 0.690 are further in this order.
By setting the mass ratio [ (SiO 2+B2O3)/(Nb2O5+TiO2) ] to the above range, a desired optical constant can be obtained. Further, the reduction of the network formation action of the glass can be suppressed, and the reduction of the stability at the time of reheating the glass can be suppressed.
In the glass of embodiment a, the upper limit of the mass ratio [ (mgo+cao+sro+bao+zno)/(Li 2O+Na2O+K2 O) ] of the total content of MgO, caO, srO, baO and ZnO to the total content of Li 2O、Na2 O and K 2 O may be set to 0.480, and more preferably in the order of 0.400, 0.350, 0.300, 0.250, 0.200, 0.150, and 0.100. The mass ratio [ (MgO+CaO+SrO+BaO+ZnO)/(Li 2O+Na2O+K2 O) ] may be 0.
By setting the mass ratio [ (mgo+cao+sro+bao+zno)/(Li 2O+Na2O+K2 O) ] to the above range, an increase in specific gravity and a decrease in thermal stability can be suppressed. Furthermore, a decrease in the refractive index nd can be suppressed.
In the glass of embodiment a, the upper limit of the mass ratio [ TiO 2/Nb2O5 ] of the content of TiO 2 to the content of Nb 2O5 may be set to 0.340, and more preferably, in order of 0.300, 0.280, 0.260, 0.240, 0.220, 0.200, and 0.180. The lower limit of the mass ratio [ TiO 2/Nb2O5 ] is preferably 0, and more preferably 0.001, 0.002, 0.003, 0.004, and 0.005 in this order.
By setting the mass ratio [ TiO 2/Nb2O5 ] to the above range, an increase in the relative partial dispersions Pg, F can be suppressed. Further, it is possible to suppress a decrease in the network formation action of the glass, a decrease in the stability of the glass upon reheating, and an increase in specific gravity.
In the glass of embodiment a, the upper limit of the mass ratio [ (Li 2O+Na2O+K2O)/(TiO2+Nb2O5) ] of the total content of Li 2O、Na2 O and K 2 O to the total content of TiO 2 and Nb 2O5 may be set to 0.700, and more preferably in the order of 0.650, 0.600, 0.570, 0.550, 0.530, 0.510, 0.500, 0.490, 0.480, 0.470, 0.460, 0.450. The lower limit of the mass ratio [ (Li 2O+Na2O+K2O)/(TiO2+Nb2O5) ] is preferably 0.100, more preferably in the order of 0.150, 0.200, 0.250, 0.270, 0.290, 0.300, 0.310, 0.320, 0.330, 0.340.
By setting the mass ratio [ (Li 2O+Na2O+K2O)/(TiO2+Nb2O5) ] to the above range, a desired optical constant can be obtained. In addition, the glass can be prevented from decreasing in melting property.
The lower limit of the total content of ,SiO2、B2O3、P2O5、Al2O3、Li2O、Na2O、K2O、MgO、CaO、ZnO、La2O3、Y2O3、Gd2O3、ZrO2、TiO2 and Nb 2O5 in the glass of embodiment a may be set to 96.0%, and more preferably 96.5%, 97.0%, 97.5%, 98.0%, 98.2%, 98.4%, 98.6%, 98.8%, 99.0% in this order. The total content may also be 100%.
By setting the total content to the above range, a desired optical constant can be obtained. In addition, the reduction of the network formation action of the glass can be suppressed, and the reduction of the stability of the glass at the time of reheating and the increase of the specific gravity can be suppressed. Further, an increase in relative partial dispersion can be suppressed.
In the glass of embodiment a, the upper limit of the contents of PbO, cdO and As 2O3 may be set to 0.01%, and more preferably, in the order of 0.005%, 0.003%, 0.002% and 0.001%, respectively. The content of PbO, cdO and As 2O3 is preferably small, but may be 0%. These components are components that may cause environmental burden, and preferably are substantially not contained.
The content and ratio of the glass components other than those described above in embodiment a may be the same as those in embodiment 1 to 1.
(Properties of glass of embodiment A)
< Abbe number vd >)
In the glass of embodiment a, the lower limit of the abbe number vd is preferably 26.0, and more preferably 26.5, 27.0, 27.2, 27.4, 27.6, 27.8, 28.0, 28.2, 28.4, 28.6, 28.8, 29.0 in this order. The upper limit of the abbe number vd is preferably 31.0, 30.8, 30.6, 30.4, 30.2, and 30.0 in this order. The component that relatively decreases the abbe number vd is Nb 2O5、TiO2、ZrO2、Ta2O5. . The component SiO2、P2O5、B2O3、Li2O、Na2O、K2O、La2O3、BaO、CaO、SrO. which relatively increases the Abbe number vd is a component which can control the Abbe number vd by properly adjusting the content of the component.
< Refractive index nd >)
In the glass of embodiment a, the refractive index nd is preferably 1.70 to 1.90. The refractive index nd may be 1.72 to 1.85, or 1.73 to 1.83. The component that relatively increases the refractive index nd is Nb 2O5、TiO2、ZrO2、Ta2O5、La2O3. The component that relatively lowers the refractive index nd is SiO 2、B2O3、Li2O、Na2O、K2 O. By properly adjusting the content of these components, the refractive index nd can be controlled.
< Relative partial Dispersion Pg, F >)
The upper limit of the relative partial dispersion Pg, F of the glass of embodiment a is preferably 0.6500, and more preferably 0.6400, 0.6300, 0.6200, 0.6100, 0.6050, 0.6040, 0.6030, 0.6020, 0.6010, and 0.6000 are further in this order. The lower limit of the relative partial dispersion Pg, F is preferably 0.5500, and may be 0.5600, 0.5700, 0.5800, 0.5840, 0.5850, 0.5870, 0.5890, 0.5900, 0.5910, 0.5920, 0.5930, 0.5940.
By setting the relative partial dispersion Pg, F to the above range, an optical glass suitable for high-order chromatic aberration correction can be obtained. The component of the relative partial dispersion Pg, F is Nb 2O5、TiO2、ZrO2、Ta2O5, which is relatively high. The relative partial dispersion Pg, F is relatively reduced and the component of the F is SiO 2、B2O3、Li2O、Na2O、K2 O. By properly adjusting the content of these components, the relative partial dispersion Pg, F can be controlled.
In the glass of embodiment A, the relative partial dispersion Pg and F preferably satisfy the above formula (1-2), more preferably satisfy the above formula (1-3), still more preferably satisfy the above formula (1-4), and particularly preferably satisfy the above formula (1-5). By satisfying the above expression, an optical glass suitable for secondary chromatic aberration correction can be provided.
The upper limit of Δpg, F' of the glass of embodiment a is preferably 0.0000, and more preferably-0.0010, -0.0020, -0.0030, -0.0040, -0.0050, and-0.0060 in this order. The lower the Δpg, the more preferable the lower limit is, -0.0200, and further, -0.0180, -0.0160, -0.0140, -0.0130, -0.0120 may be used. The component of Δpg, F' is relatively increased to P 2O5、B2O3、TiO2. The components of Δpg, F 'are relatively reduced to Nb2O5、La2O3、Y2O3、ZrO2、Li2O、Na2O、K2O., and Δpg, F' can be controlled by appropriately adjusting the content of these components.
In the glass of embodiment a, the deviation Δpg, F' is represented as follows.
ΔPg,F’＝Pg,F+(0.00286×νd)-0.68900
< Specific gravity of glass >
The specific gravity of the glass of embodiment a is preferably 3.60 or less, more preferably 3.55 or less, 3.50 or less, 3.48 or less, 3.46 or less, 3.45 or less, 3.44 or less, 3.43 or less, 3.42 or less, 3.41 or less, and 3.40 or less. The lower limit is not particularly limited as the specific gravity is smaller, but is generally about 3.00. The components that relatively increase the specific gravity are BaO, la 2O3、ZrO2、Nb2O5、Ta2O5, and the like. The component that relatively reduces the specific gravity is SiO 2、B2O3、Li2O、Na2O、K2 O or the like. The specific gravity can be controlled by adjusting the content of these components.
< Glass transition temperature Tg >)
The upper limit of the glass transition temperature Tg of the glass of embodiment A is preferably 700℃and more preferably 670℃650℃630℃620℃610℃600℃590 ℃. The lower limit of the glass transition temperature Tg is preferably 450℃and more preferably 470℃and 500℃and 510℃and 520℃and 530℃and 540 ℃. The component that relatively lowers the glass transition temperature Tg is Li 2O、Na2O、K2 O or the like. The component that relatively increases the glass transition temperature Tg is La 2O3、ZrO2、Nb2O5 or the like. By properly adjusting the content of these components, the glass transition temperature Tg can be controlled.
Light transmittance of glass
The light transmittance of the glass of embodiment a can be evaluated by the coloring degrees λ70 and λ5.
For a glass sample having a thickness of 10.0 mm.+ -. 0.1mm, the spectral transmittance was measured in the wavelength range of 200 to 700nm, the wavelength at which the external transmittance reached 70% was represented by λ70, and the wavelength at which the external transmittance reached 5% was represented by λ5.
The glass according to embodiment A has a lambda 70 of preferably 500nm or less, more preferably 470nm or less, still more preferably 450nm or less, and still more preferably 430nm or less. Also, λ5 is preferably 400nm or less, more preferably 380nm or less, and still more preferably 370nm or less. The coloring degrees λ70 and λ5 can be controlled by adjusting the content of ZrO 2、Nb2O5、TiO2、SiO2、B2O3.
< Stability upon reheat >
The glass of embodiment A preferably does not show cloudiness when heated in a test furnace set at a temperature 200 to 220 ℃ higher than the glass transition temperature Tg for 5 minutes. More preferably, the number of crystals deposited by the heating is 100 or less per 1 sample. Stability upon reheating can be controlled by adjusting the Nb2O5、TiO2、SiO2、B2O3、Li2O、Na2O、K2O、P2O5 content.
Stability upon reheating was measured as follows. After heating a glass sample having a size of 10mm×10mm×7.5mm in a test furnace set to a temperature 200 to 220 ℃ higher than the glass transition temperature Tg of the glass sample for 5 minutes, the number of crystals per 1 sample was measured by an optical microscope (observation magnification: 40 to 200 times). In addition, the presence or absence of cloudiness of the glass was visually confirmed.
The glass characteristics other than those described above in embodiment a can be the same as those in embodiment 1 to 1. The production of optical glass and the production of optical elements and the like may be the same as those in embodiment 1 to 1.
Embodiment B
The glass of embodiment B is characterized in that,
The mass ratio of the content of SiO 2 to the content of Nb 2O5 [ SiO 2/Nb2O5 ] is more than 1.05,
The mass ratio [ ZrO 2/Nb2O5 ] of the content of ZrO 2 relative to the content of Nb 2O5 is more than 0.25,
The mass ratio of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] is greater than 0.65.
The glass of embodiment B has a relatively small specific gravity and a small relative partial dispersion Pg and F.
In the glass of embodiment B, the mass ratio of the content of SiO 2 to the content of Nb 2O5 [ SiO 2/Nb2O5 ] may be made larger than 1.05, and the lower limit thereof is more preferably in the order of 1.09, 1.11, 1.15, and 1.17. The upper limit of the mass ratio [ SiO 2/Nb2O5 ] is preferably 2.10, more preferably in the order of 2.05, 2.00, and 1.95. By setting the mass ratio [ SiO 2/Nb2O5 ] to the above range, the specific gravity of the glass can be reduced while maintaining desired optical constants (refractive index nd, abbe number vd).
In the glass of embodiment B, the mass ratio [ ZrO 2/Nb2O5 ] of the content of ZrO 2 with respect to the content of Nb 2O5 may be made larger than 0.25, and the lower limit thereof is more preferably in the order of 0.26, 0.27, 0.28, 0.29, 0.30, 0.305, 0.310, 0.315. The upper limit of the mass ratio [ ZrO 2/Nb2O5 ] is preferably 0.65, and more preferably in the order of 0.61, 0.57, and 0.53. By setting the lower limit of the mass ratio [ ZrO 2/Nb2O5 ] to the above range, the relative partial dispersions Pg, F can be reduced, the raw material cost can be reduced, and the desired optical constant and solubility can be maintained.
In the glass of embodiment B, the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 may be set to be larger than 0.65, and the lower limit thereof is more preferably in the order of 0.66, 0.67, 0.69, 0.70, 0.71, 0.73, 0.75, 0.76, 0.77, 0.79, 0.80, 0.83, 0.86, 0.88. The upper limit of the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] is preferably 1.20, and more preferably 1.15, 1.14, 1.13, 1.12, 1.11, 1.10, and 1.09 are further in this order. By setting the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] to the above range, the thermal stability of the glass can be maintained, and a desired optical constant can be obtained.
In the glass of embodiment B, the total content of TiO 2 and BaO [ TiO 2 +BaO ] is preferably less than 10%, and the upper limit thereof is more preferably in the order of 8.0%, 7.8%, 7.6% and 7.4%. The lower limit of the total content [ Ti 2 +BaO ] is preferably 0%, more preferably in the order of 1%, 2% and 3%. By setting the upper limit of the total content [ Ti 2 +BaO ] to the above range, the relative partial dispersions Pg, F can be reduced, and the specific gravity of the glass can be reduced.
In the glass of embodiment B, the mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] of the content of Ta 2O5 to the total content of TiO 2 and Nb 2O5 is preferably less than 0.3, and the upper limit thereof is more preferably in the order of 0.25, 0.20, and 0.15. The lower limit of the mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] is preferably 0, and more preferably in the order of 0.05, 0.07, and 0.10. The mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] may also be 0. By setting the upper limit of the mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] to the above range, the specific gravity of glass can be reduced, and the raw material cost can be reduced.
In the glass of embodiment B, the mass ratio [ ZnO/Nb 2O5 ] of the content of ZnO to the content of Nb 2O5 is preferably less than 0.14, and the upper limit thereof is more preferably in the order of 0.125, 0.115, and 0.105. The lower limit of the mass ratio [ ZnO/Nb 2O5 ] is preferably 0, and more preferably 0.02, 0.05, and 0.07. The mass ratio [ ZnO/Nb 2O5 ] may be 0. By setting the upper limit of the mass ratio [ ZnO/Nb 2O5 ] to the above range, the specific gravity of the glass can be reduced, and a desired optical constant can be obtained.
In the glass of embodiment B, the mass ratio of the total content R 2 O [ R 2O/(R2 o+r 'O) ] to the total content R 2 O and MgO, caO, srO of Li 2O、Na2 O and K 2 O and the total content R' O of BaO may be set to be more than 0.05. The mass ratio [ R 2O/(R2 O+R' O) ] is preferably more than 0.6, and the lower limit thereof is more preferably in the order of 0.80, 0.82, 0.84, 0.86. The upper limit of the mass ratio [ R 2O/(R2 O+R' O) ] is preferably 1.00, and more preferably in the order of 0.99, 0.98, and 0.95. By setting the mass ratio [ R 2O/(R2 O+R' O) ] to the above range, the specific gravity of the glass can be reduced, and the stability of the glass at the time of reheating can be maintained.
The content and ratio of the glass components other than those described above in embodiment B may be the same as those in embodiment 1 to 1.
(Properties of glass of embodiment B)
< Refractive index nd >)
In the glass of embodiment B, the refractive index nd is preferably 1.69 to 1.76. The refractive index nd may be 1.695 to 1.755 or 1.70 to 1.75. The component that relatively increases the refractive index nd is Nb 2O5、TiO2、ZrO2、Ta2O5、La2O3. The component that relatively lowers the refractive index nd is SiO 2、B2O3、Li2O、Na2O、K2 O. By properly adjusting the content of these components, the refractive index nd can be controlled.
< Abbe number vd >)
In the glass of embodiment B, the abbe number vd is preferably 30 to 36. The Abbe number vd may be 30.5 to 35.8 or 31 to 35.5. The component that relatively decreases the abbe number vd is Nb 2O5、TiO2、ZrO2、Ta2O5. The component SiO2、B2O3、Li2O、Na2O、K2O、La2O3、BaO、CaO、SrO. which relatively increases the Abbe number vd is a component which can control the Abbe number vd by properly adjusting the content of the component.
< Specific gravity of glass >
The specific gravity of the glass of embodiment B is preferably 3.19 or less, more preferably 3.18 or less, 3.17 or less, and 3.16 or less. The lower limit is not particularly limited as the specific gravity is smaller, but is generally about 3.05. The components that relatively increase the specific gravity are BaO, la 2O3、ZrO2、Nb2O5、Ta2O5, and the like. The component that relatively reduces the specific gravity is SiO 2、B2O3、Li2O、Na2O、K2 O or the like. The specific gravity can be controlled by adjusting the content of these components.
< Relative partial Dispersion Pg, F >)
The upper limit of the relative partial dispersion Pg, F of the glass of embodiment B is preferably 0.5950, and more preferably 0.5945, 0.5940, 0.5935 are further preferred. The lower limit of the relative partial dispersion Pg, F is preferably 0.5780, and more preferably 0.5785, 0.5790, 0.5795, 0.5805, 0.5815, 0.5830 are further preferable. By setting the relative partial dispersion Pg, F to the above range, an optical glass suitable for high-order chromatic aberration correction can be obtained.
The upper limit of the deviation Δpg of the relative partial dispersion Pg, F of the glass of embodiment B is preferably 0.0015, and more preferably in the order of 0.0012, 0.0010, and 0.0008. The lower limit of the deviation Δpg, F is preferably-0.0060, more preferably-0.0048, -0.0045, -0.0042, -0.0040, -0.0035, and-0.0025.
< Liquid phase temperature >)
The glass of embodiment B preferably has a liquid phase temperature LT of 1200 ℃ or lower, more preferably 1190 ℃ or lower, 1180 ℃ or lower, and 1170 ℃ or lower. By setting the liquid phase temperature to the above range, the melting and forming temperatures of the glass can be reduced, and as a result, erosion of glass melting devices (e.g., a crucible, a stirrer for melting glass, etc.) in the melting step can be reduced. The lower limit of the liquid phase temperature LT is not particularly limited, but is generally about 1000 ℃. The liquidus temperature LT is determined based on the balance of the contents of all glass components. Among them, the content of SiO 2、B2O3、Li2O、Na2O、K2 O and the like has a large influence on the liquid phase temperature LT.
The liquid phase temperature was determined as follows. 10cc (10 ml) of glass was charged into a platinum crucible, melted at 1250 to 1400 ℃ for 15 to 30 minutes, cooled to a temperature below the glass transition temperature Tg, and the glass was charged into a melting furnace at a given temperature together with the platinum crucible and kept for 2 hours. The temperature was kept at 1000℃or higher, and at 5℃or 10℃intervals, the glass was cooled after 2 hours, and the presence or absence of crystals in the glass was observed with a 100-fold optical microscope. The minimum temperature at which no crystals precipitate was set to the liquid phase temperature.
< Glass transition temperature Tg >)
The upper limit of the glass transition temperature Tg of the glass of embodiment B is preferably 580℃and more preferably in the order of 575℃and 570℃and 565 ℃. The lower limit of the glass transition temperature Tg is preferably 510℃and more preferably 515℃and 520℃and 525 ℃. The component that relatively lowers the glass transition temperature Tg is Li 2O、Na2O、K2 O or the like. The component that relatively increases the glass transition temperature Tg is La 2O3、ZrO2、Nb2O5 or the like. By properly adjusting the content of these components, the glass transition temperature Tg can be controlled.
< Stability upon reheat >
In the glass of embodiment B, the glass is heated at the glass transition temperature Tg for 10 minutes and further heated at a temperature 140 to 250℃higher than the Tg for 10 minutes, and the number of crystals observed per 1g is preferably 20 or less, more preferably 10 or less.
The stability at the time of reheating was measured as follows. A glass sample having a size of 1cm by 0.8cm was heated in a 1 st test furnace set to a glass transition temperature Tg of the glass sample for 10 minutes, and further heated in a2 nd test furnace set to a temperature 140 to 250℃higher than the glass transition temperature Tg for 10 minutes, and then the presence or absence of crystallization was confirmed by an optical microscope (observation magnification: 10 to 100 times). Then, the corresponding number of crystals per 1g was measured. In addition, the presence or absence of cloudiness of the glass was visually confirmed.
The glass characteristics other than those described above in embodiment B may be the same as those in embodiment 1 to 1. The production of optical glass and the production of optical elements and the like may be the same as those in embodiment 1 to 1.
Embodiment C
The glass of embodiment C is characterized in that,
The mass ratio of the content of SiO 2 to the total content of Nb 2O5 and TiO 2 [ SiO 2/(Nb2O5+TiO2) ] is greater than 0.80,
The mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] of the total content of SiO 2、B2O3 and P 2O5 to the total content of Li 2O、Na2 O and K 2 O is 1.45-4.55,
The total content of SiO 2 and Nb 2O5 [ SiO 2+Nb2O5 ] is 62-84%.
The glass of embodiment C has a small specific gravity and a small relative partial dispersion Pg, F.
In the glass of embodiment C, the mass ratio [ SiO 2/(Nb2O5+TiO2 ] of the content of SiO 2 to the total content of Nb 2O5 and TiO 2 is preferably more than 0.80, and the lower limit thereof is more preferably in the order of 0.83, 0.85, 0.86, 0.87, and 0.88. The upper limit of the mass ratio [ SiO 2/(Nb2O5+TiO2) ] is preferably 1.50, more preferably in the order of 1.40, 1.30, 1.20. By setting the mass ratio [ SiO 2/(Nb2O5+TiO2) ] to the above range, crystallization of the glass can be suppressed, and a glass excellent in homogeneity and stability upon reheating can be obtained.
In the glass of embodiment C, the mass ratio of the content of SiO 2 to the content of Na 2 O [ SiO 2/Na2 O ] is preferably 2.5 to 8.5. The lower limit of the mass ratio [ SiO 2/Na2 O ] is more preferably 2.6, and further more preferably in the order of 2.65, 2.70, 2.75. The upper limit of the mass ratio [ SiO 2/Na2 O ] is more preferably 8.2, and further more preferably in the order of 8.0, 7.8, and 7.6. By setting the mass ratio [ SiO 2/Na2 O ] to the above range, a glass excellent in homogeneity and stability upon reheating can be obtained.
In the glass of embodiment C, the mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] of the total content of SiO 2、B2O3 and P 2O5 to the total content of Li 2O、Na2 O and K 2 O may be set to 1.45 to 4.55. The lower limit of the mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] is more preferably 1.70, and further more preferably in the order of 1.72, 1.74, 1.76. The upper limit of the mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] is more preferably 4.20, and further more preferably in the order of 4.00, 3.95, and 3.90. By setting the mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] to the above range, crystallization of the glass can be suppressed.
In the glass of embodiment C, the total content of SiO 2 and Nb 2O5 [ SiO 2+Nb2O5 ] may be set to 62 to 84%. The lower limit of the total content [ SiO 2+Nb2O5 ] is more preferably 63.0%, and further more preferably in the order of 63.5%, 64.0%, 64.5%. The upper limit of the total content [ SiO 2+Nb2O5 ] is more preferably 83%, and further more preferably 82.7%, 82.3%, 82.1% in this order. By setting the total content [ SiO 2+Nb2O5 ] to the above range, the liquid phase temperature can be reduced, and the thermal stability of the glass can be improved. Furthermore, crystallization of the glass can be suppressed.
The content and ratio of the glass components other than those described above in embodiment C may be the same as those in embodiment 1 to 1.
(Properties of glass of embodiment C)
< Refractive index nd >)
In the glass of embodiment C, the refractive index nd is preferably 1.690 to 1.760. The refractive index nd may be 1.695 to 1.755, or 1.700 to 1.750. The component that relatively increases the refractive index nd is Nb 2O5、TiO2、ZrO2、Ta2O5、La2O3. The component that relatively lowers the refractive index nd is SiO 2、B2O3、Li2O、Na2O、K2 O. By properly adjusting the content of these components, the refractive index nd can be controlled.
< Abbe number vd >)
In the glass of embodiment C, the abbe number vd is preferably 30 to 36. The Abbe number vd may be 30.5 to 35.8 or 31 to 35.5. The component that relatively decreases the abbe number vd is Nb 2O5、TiO2、ZrO2、Ta2O5. The component SiO2、B2O3、Li2O、Na2O、K2O、La2O3、BaO、CaO、SrO. which relatively increases the Abbe number vd is a component which can control the Abbe number vd by properly adjusting the content of the component.
< Specific gravity of glass >
The specific gravity of the glass of embodiment C is preferably 3.40 or less, more preferably 3.35 or less, 3.30 or less, and still more preferably 3.25 or less. The lower limit is not particularly limited as the specific gravity is smaller, but is generally about 3.10. The components that relatively increase the specific gravity are BaO, la 2O3、ZrO2、Nb2O5、Ta2O5, and the like. The component that relatively reduces the specific gravity is SiO 2、B2O3、Li2O、Na2O、K2 O or the like. The specific gravity can be controlled by adjusting the content of these components.
< Relative partial Dispersion Pg, F >)
The upper limit of the relative partial dispersion Pg, F of the glass of embodiment C is preferably 0.5980, and more preferably in the order of 0.5970, 0.5960, 0.5950, 0.5940. The lower limit of the relative partial dispersion Pg, F is preferably 0.5780, and 0.5800, 0.5820, 0.5840, 0.5860 may be further used. By setting the relative partial dispersion Pg, F to the above range, an optical glass suitable for high-order chromatic aberration correction can be obtained. The relative partial dispersion Pg, F can be controlled by adjusting the content of SiO 2、B2O3、TiO2、Nb2O5 or the like.
The upper limit of the deviation Δpg of the relative partial dispersion Pg, F of the glass of embodiment C is preferably 0.0030, and more preferably in the order of 0.0025, 0.0020, and 0.0015. The lower limit of the deviation Δpg, F is preferably-0.0060, and may be-0.0050, -0.0040, -0.0030, or-0.0020.
< Liquid phase temperature >)
The glass of embodiment C preferably has a liquid phase temperature LT of 1200 ℃ or lower, more preferably 1190 ℃ or lower, 1180 ℃ or lower, and 1170 ℃ or lower. By setting the liquid phase temperature to the above range, the melting and forming temperatures of the glass can be reduced, and as a result, erosion of glass melting devices (e.g., a crucible, a stirrer for melting glass, etc.) in the melting step can be reduced. The lower limit of the liquid phase temperature LT is not particularly limited, but is generally about 1000 ℃. The liquidus temperature LT is determined based on the balance of the contents of all glass components. Among them, the content of SiO 2、B2O3、Li2O、Na2O、K2 O and the like has a large influence on the liquid phase temperature LT.
The liquid phase temperature was determined as follows. 10cc (10 ml) of glass was charged into a platinum crucible, melted at 1250 to 1400 ℃ for 15 to 30 minutes, cooled to a temperature below the glass transition temperature Tg, and the glass was charged into a melting furnace at a given temperature together with the platinum crucible and kept for 2 hours. The temperature was kept at 1000℃or higher, and at 5℃or 10℃intervals, the glass was cooled after 2 hours, and the presence or absence of crystals in the glass was observed with a 100-fold optical microscope. The minimum temperature at which no crystals precipitate was set to the liquid phase temperature.
< Glass transition temperature Tg >)
The upper limit of the glass transition temperature Tg of the glass of embodiment C is preferably 670℃and more preferably in the order of 650℃630℃and 610 ℃. The lower limit of the glass transition temperature Tg is preferably 510℃and more preferably 520℃and 525℃and 530 ℃. The component that relatively lowers the glass transition temperature Tg is Li 2O、Na2O、K2 O or the like. The component that relatively increases the glass transition temperature Tg is La 2O3、ZrO2、Nb2O5 or the like. By properly adjusting the content of these components, the glass transition temperature Tg can be controlled.
< Stability upon reheat >
In the glass of embodiment C, the number of crystals observed per 1g is preferably 20 or less, more preferably 10 or less, when heated at the glass transition temperature Tg for 10 minutes and further heated at a temperature 140 to 220℃higher than the Tg for 10 minutes.
The stability at the time of reheating was measured as follows. A glass sample having a size of 1cm by 0.8cm was heated in a1 st test furnace set to a glass transition temperature Tg of the glass sample for 10 minutes, and further heated in a 2 nd test furnace set to a temperature 140 to 220 ℃ higher than the glass transition temperature Tg for 10 minutes, and then the presence or absence of crystallization was confirmed by an optical microscope (observation magnification: 10 to 100 times). Then, the corresponding number of crystals per 1g was measured. In addition, the presence or absence of cloudiness of the glass was visually confirmed.
The glass characteristics other than those described above in embodiment C may be the same as those in embodiment 1 to 1. The production of optical glass and the production of optical elements and the like may be the same as those in embodiment 1 to 1.
2 Nd invention
[ Background of the invention 2]
For an optical element mounted in an optical system of an auto-focus system, weight reduction is required in order to reduce power consumption when an auto-focus function is driven. If the specific gravity of the glass can be reduced, the weight of the optical element such as a lens can be reduced. In addition, for correction of chromatic aberration, the relative partial dispersion Pg, F is required to be small.
Further, as a method for producing such an optical glass used in an optical system, a reheat press method in which glass is reheated and shaped is exemplified. In this method, devitrification is observed in silicate-based optical glass having a high refractive index and high dispersibility. In addition, high stability is required that devitrification is less likely to occur inside the glass upon reheating of the glass.
Patent documents 2-1 to 2-3 disclose optical glasses that have a predetermined optical constant and that reduce relative partial dispersion. However, the optical glasses disclosed in patent documents 2-1 to 2-3 have a large specific gravity.
Patent documents 2 to 4 have an object of obtaining an optical glass having a small relative partial dispersion at low cost. However, the optical glasses disclosed in patent documents 2 to 4 are glasses having relatively low dispersibility, and do not have the optical constants desired in invention 2.
[ Prior Art document of the invention 2]
Patent literature
Patent document 2-1: japanese patent laid-open No. 2015-193515
Patent document 2-2: japanese patent application laid-open No. 2015-193516
Patent documents 2 to 3: japanese patent laid-open publication 2016-88759
Patent documents 2 to 4: japanese patent laid-open No. 2017-105702
[2 Nd summary ]
[ Problem to be solved by the invention 2]
The object of the invention of claim 2 is to provide an optical glass having a desired optical constant, a relatively small specific gravity, a small relative partial dispersion Pg and F with respect to abbe number vd, and excellent stability upon reheating, and an optical element formed of the optical glass.
[ Means of solving the problems ]
The gist of invention 2 is as follows.
(1) An optical glass having an Abbe number vd of 26.0 or more,
The content of SiO 2 is more than 0 mass% and less than 40 mass%,
The content of TiO 2 is 0 to 15 mass percent,
The content of Nb 2O5 is 25 to 45 mass%,
The content of ZrO 2 is more than 0 mass%,
The mass ratio [ B 2O3/SiO2 ] of the content of B 2O3 to the content of SiO 2 is 0.800 or less,
The mass ratio [ (SiO 2+B2O3)/(Nb2O5+TiO2) ] of the total content of SiO 2 and B 2O3 to the total content of Nb 2O5 and TiO 2 is 0.950 or less,
The total content of Li 2O、Na2 O and K 2 O [ Li 2O+Na2O+K2 O ] is 10 to 25 mass%,
The mass ratio of Na 2 O content to the total content of Li 2O、Na2 O and K 2 O [ Na 2O/(Li2O+Na2O+K2 O) ] is 0.330 or more,
The mass ratio of the total content of MgO, caO, srO, baO and ZnO to the total content of Li 2O、Na2 O and K 2 O [ (MgO+CaO+SrO+BaO+ZnO)/(Li 2O+Na2O+K2 O) ] is 0.480 or less,
The mass ratio of the content of TiO 2 to the content of Nb 2O5 [ TiO 2/Nb2O5 ] is 0.340 or less,
The mass ratio [ (Li 2O+Na2O+K2O)/(TiO2+Nb2O5) ] of the total content of Li 2O、Na2 O and K 2 O to the total content of TiO 2 and Nb 2O5 is 0.700 or less,
SiO2、B2O3、P2O5、Al2O3、Li2O、Na2O、K2O、MgO、CaO、ZnO、La2O3、Y2O3、Gd2O3、ZrO2、TiO2 And the total content of Nb 2O5 is 96.0 mass% or more,
The contents of PbO, cdO and As 2O3 are respectively below 0.01 mass%.
(2) An optical element formed of the optical glass according to (1) above.
[ Effect of the invention 2]
According to the invention of claim 2, an optical glass having a desired optical constant, a relatively small specific gravity, a small relative partial dispersion Pg and F with respect to the abbe number vd, and excellent stability upon reheating, and an optical element formed of the optical glass can be provided.
[ Detailed description of the invention ] 2
Hereinafter, the glass according to embodiment 2 of the present invention will be described as embodiment 2.
In embodiment 2, the relative partial dispersions Pg and F are represented by refractive indices ng, nF, and nC in g-rays, F-rays, and C-rays as follows.
Pg,F＝(ng-nF)/(nF-nC)
In a plane where the horizontal axis is the abbe number vd and the vertical axis is the relative partial dispersion Pg, F, the normal line in embodiment 2 is expressed by the following formula.
Pg,F(0)’＝0.68900-0.00286×νd
The deviation Δpg, F' of the relative partial dispersion Pg, F with respect to the normal line is expressed as follows.
ΔPg,F’＝Pg,F-Pg,F(0)’
The optical glass of embodiment 2 is characterized in that the Abbe number vd is 26.0 or more,
The content of SiO 2 is more than 0% and less than 40%,
The content of TiO 2 is 0-15%,
The content of Nb 2O5 is 25-45%,
The content of ZrO 2 is more than 0%,
The mass ratio [ B 2O3/SiO2 ] of the content of B 2O3 to the content of SiO 2 is 0.800 or less,
The mass ratio [ (SiO 2+B2O3)/(Nb2O5+TiO2) ] of the total content of SiO 2 and B 2O3 to the total content of Nb 2O5 and TiO 2 is 0.950 or less,
The total content of Li 2O、Na2 O and K 2 O [ Li 2O+Na2O+K2 O ] is 10-25%,
The mass ratio of Na 2 O content to the total content of Li 2O、Na2 O and K 2 O [ Na 2O/(Li2O+Na2O+K2 O) ] is 0.330 or more,
The mass ratio of the total content of MgO, caO, srO, baO and ZnO to the total content of Li 2O、Na2 O and K 2 O [ (MgO+CaO+SrO+BaO+ZnO)/(Li 2O+Na2O+K2 O) ] is 0.480 or less,
The mass ratio of the content of TiO 2 to the content of Nb 2O5 [ TiO 2/Nb2O5 ] is 0.340 or less,
The mass ratio [ (Li 2O+Na2O+K2O)/(TiO2+Nb2O5) ] of the total content of Li 2O、Na2 O and K 2 O to the total content of TiO 2 and Nb 2O5 is 0.700 or less,
SiO2、B2O3、P2O5、Al2O3、Li2O、Na2O、K2O、MgO、CaO、ZnO、La2O3、Y2O3、Gd2O3、ZrO2、TiO2 And the total content of Nb 2O5 is more than 96.0 percent,
The contents of PbO, cdO and As 2O3 are respectively below 0.01%.
In the optical glass of embodiment 2, the abbe number vd is 26.0 or more. The lower limit of the abbe number vd is preferably 26.5, more preferably in the order of 27.0, 27.2, 27.4, 27.6, 27.8, 28.0, 28.2, 28.4, 28.6, 28.8, 29.0. The upper limit of the abbe number vd is preferably 31.0, 30.8, 30.6, 30.4, 30.2, and 30.0 in this order. The component that relatively decreases the abbe number vd is Nb 2O5、TiO2、ZrO2、Ta2O5. The component SiO2、P2O5、B2O3、Li2O、Na2O、K2O、La2O3、BaO、CaO、SrO. which relatively increases the Abbe number vd is a component which can control the Abbe number vd by properly adjusting the content of the component.
In the optical glass of embodiment 2, the content of SiO 2 is more than 0% and less than 40%. The lower limit of the content of SiO 2 is preferably 10%, more preferably in the order of 15%, 17%, 19%, 21%, 23%, 25%, 26%, 27%, 28%. The upper limit of the content of SiO 2 is preferably 39%, more preferably in the order of 38%, 37%, 36%, 35%, 34%, 33%.
SiO 2 is a network forming component of glass. When the content of SiO 2 is too small, there is a possibility that the network formation effect of the glass is reduced and the stability of the glass upon reheating is lowered. If the content of SiO 2 is too large, there is a possibility that a desired optical constant cannot be obtained.
In the optical glass of embodiment 2, the content of TiO 2 is 0 to 15%. The upper limit of the content of TiO 2 is preferably 14%, and more preferably 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6% in this order. The lower limit of the content of TiO 2 is preferably 0.05%, more preferably in the order of 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%.
TiO 2 is a component for highly dispersing glass. If the content of TiO 2 is too large, there is a possibility that the relative partial dispersion Pg and F increases. Too small a content of TiO 2 has a risk of failing to obtain a desired optical constant. In addition, there is a risk that the network formation effect of the glass is reduced and the stability of the glass upon reheating is lowered.
In the optical glass of embodiment 2, the content of Nb 2O5 is 25 to 45%. The lower limit of the content of Nb 2O5 is preferably 27%, more preferably in the order of 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%. The upper limit of the content of Nb 2O5 is preferably 44.5%, more preferably 44.0%, 43.5%, 43.2%, 43.0%, 42.7%, and 42.5%.
Nb 2O5 is a component for increasing the dispersion of glass and reducing the relative partial dispersion Pg and F. If the content of Nb 2O5 is too large, there is a risk that the thermal stability of the glass is lowered and the cost of raw materials is increased. When the content of Nb 2O5 is too small, there is a possibility that the relative partial dispersion Pg, F increases and a desired optical constant cannot be obtained.
In the optical glass of embodiment 2, the content of ZrO 2 is more than 0%. The lower limit of the content of ZrO 2 is preferably 1%, more preferably in the order of 2%, 3%, 4%, 5%, 6%, 7%, 8%. The upper limit of the content of ZrO 2 is preferably 15%, more preferably in the order of 14%, 13.5%, 13.2%, 13.0%, 12.8%, 12.6%, 12.4%.
ZrO 2 is a component for increasing the dispersion of glass and reducing the relative partial dispersion Pg and F. If the content of ZrO 2 is too large, there is a risk that the network formation effect of the glass is reduced and the stability of the glass is lowered when the glass is reheated. When the content of ZrO 2 is too small, there is a possibility that the relative partial dispersion Pg, F increases and a desired optical constant cannot be obtained.
In the optical glass of embodiment 2, the mass ratio [ B 2O3/SiO2 ] of the content of B 2O3 to the content of SiO 2 is 0.800 or less. The upper limit of the mass ratio [ B 2O3/SiO2 ] is preferably 0.700, more preferably in the order of 0.600, 0.550, 0.500, 0.450, 0.350, 0.300, 0.250, 0.200. The mass ratio [ B 2O3/SiO2 ] may also be 0.
When the mass ratio [ B 2O3/SiO2 ] is too large, there is a possibility that the specific gravity is increased and the coloring of glass is increased.
In the optical glass of embodiment 2, the mass ratio [ (SiO 2+B2O3)/(Nb2O5+TiO2) ] of the total content of SiO 2 and B 2O3 to the total content of Nb 2O5 and TiO 2 is 0.950 or less. The upper limit of the mass ratio [ (SiO 2+B2O3)/(Nb2O5+TiO2) ] is preferably 0.930, more preferably in the order of 0.920, 0.910, 0.900, 0.890, 0.880, 0.870, 0.860, 0.850, 0.840, 0.830, 0.820, 0.810, 0.800, 0.790, 0.780. The lower limit of the mass ratio [ (SiO 2+B2O3)/(Nb2O5+TiO2) ] is preferably 0.300, and more preferably 0.350, 0.400, 0.450, 0.500, 0.550, 0.600, 0.630, 0.650, 0.670, 0.680, and 0.690 are further in this order.
If the mass ratio [ (SiO 2+B2O3)/(Nb2O5+TiO2) ] is too large, there is a possibility that a desired optical constant cannot be obtained. When the mass ratio [ (SiO 2+B2O3)/(Nb2O5+TiO2) ] is too small, there is a possibility that the network formation effect of the glass is lowered and the stability of the glass upon reheating is lowered.
The optical glass of embodiment 2 has a total content of Li 2O、Na2 O and K 2 O [ Li 2O+Na2O+K2 O ] of 10 to 25%. The lower limit of the total content [ Li 2O+Na2O+K2 O ] is preferably 11.0%, more preferably in the order of 12.0%, 12.5%, 13.0%, 13.5%, 13.7%, 13.9%, 14.1%, 14.3%, 14.5%. The upper limit of the total content [ Li 2O+Na2O+K2 O ] is preferably 23%, and more preferably 22%, 21.5%, 21.0%, 20.5%, 20.0%, 19.5%, 19.0% in this order.
If the total content [ Li 2O+Na2O+K2 O ] is too large, there is a risk that the network formation effect of the glass is reduced and the stability of the glass upon reheating is lowered. In addition, there is a risk of shortening the life of refractories such as glass kilns. When the total content [ Li 2O+Na2O+K2 O ] is too small, there is a possibility that the glass may have a low melting property.
In the optical glass of embodiment 2, the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] of the Na 2 O content to the total content of Li 2O、Na2 O and K 2 O is 0.330 or more. The lower limit of the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] is preferably 0.380, more preferably in the order of 0.420, 0.440, 0.460, 0.480, 0.500, 0.520, 0.540, 0.560, 0.580, 0.600. The upper limit of the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] is preferably 1.000, and more preferably in the order of 0.950, 0.900, 0.880, 0.860, 0.840, 0.820, 0.800, 0.780, 0.760, 0.740, 0.720, 0.700.
When the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] is too large, there is a risk that the thermal stability of the glass is lowered. When the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] is too small, there is a risk of increasing the specific gravity and lowering the thermal stability, and a risk of increasing the cost of raw materials.
In the optical glass of embodiment 2, the mass ratio [ (mgo+cao+sro+bao+zno)/(Li 2O+Na2O+K2 O) ] of the total content of MgO, caO, srO, baO and ZnO to the total content of Li 2O、Na2 O and K 2 O is 0.480 or less. The upper limit of the mass ratio [ (MgO+CaO+SrO+BaO+ZnO)/(Li 2O+Na2O+K2 O) ] is preferably 0.400, more preferably in the order of 0.350, 0.300, 0.250, 0.200, 0.150, 0.100. The mass ratio [ (MgO+CaO+SrO+BaO+ZnO)/(Li 2O+Na2O+K2 O) ] may be 0.
If the mass ratio [ (mgo+cao+sro+bao+zno)/(Li 2O+Na2O+K2 O) ] is too large, there is a possibility that the specific gravity increases and the thermal stability decreases. When the mass ratio [ (MgO+CaO+SrO+BaO+ZnO)/(Li 2O+Na2O+K2 O) ] is too small, there is a possibility that the refractive index nd is lowered.
In the optical glass of embodiment 2, the mass ratio [ TiO 2/Nb2O5 ] of the content of TiO 2 to the content of Nb 2O5 is 0.340 or less. The upper limit of the mass ratio [ TiO 2/Nb2O5 ] is preferably 0.300, more preferably in the order of 0.280, 0.260, 0.240, 0.220, 0.200, 0.180. The lower limit of the mass ratio [ TiO 2/Nb2O5 ] is preferably 0, and more preferably 0.001, 0.002, 0.003, 0.004, and 0.005 in this order.
When the mass ratio [ TiO 2/Nb2O5 ] is too large, there is a hidden danger that the relative partial dispersion Pg, F increases. When the mass ratio [ TiO 2/Nb2O5 ] is too small, there are the problems of a decrease in network formation action of the glass, a decrease in stability of the glass upon reheating, and an increase in specific gravity.
In the optical glass of embodiment 2, the mass ratio [ (Li 2O+Na2O+K2O)/(TiO2+Nb2O5) ] of the total content of Li 2O、Na2 O and K 2 O to the total content of TiO 2 and Nb 2O5 is 0.700 or less. The upper limit of the mass ratio [ (Li 2O+Na2O+K2O)/(TiO2+Nb2O5) ] is preferably 0.650, more preferably in the order of 0.600, 0.570, 0.550, 0.530, 0.510, 0.500, 0.490, 0.480, 0.470, 0.460, 0.450. The lower limit of the mass ratio [ (Li 2O+Na2O+K2O)/(TiO2+Nb2O5) ] is preferably 0.100, more preferably in the order of 0.150, 0.200, 0.250, 0.270, 0.290, 0.300, 0.310, 0.320, 0.330, 0.340.
If the mass ratio [ (Li 2O+Na2O+K2O)/(TiO2+Nb2O5) ] is too large, there is a possibility that a desired optical constant cannot be obtained. If the mass ratio [ (Li 2O+Na2O+K2O)/(TiO2+Nb2O5) ] is too small, there is a possibility that the glass will be reduced in melting property.
The total content of ,SiO2、B2O3、P2O5、Al2O3、Li2O、Na2O、K2O、MgO、CaO、ZnO、La2O3、Y2O3、Gd2O3、ZrO2、TiO2 and Nb 2O5 in the optical glass of the present embodiment is 96.0% or more. The lower limit of the total content is preferably 96.5%, more preferably in the order of 97.0%, 97.5%, 98.0%, 98.2%, 98.4%, 98.6%, 98.8%, 99.0%. The total content may also be 100%.
When the total content is too small, there is a possibility that a desired optical constant cannot be obtained. In addition, there are a risk of a decrease in network formation action of glass, a decrease in stability at reheating of glass, a risk of an increase in specific gravity, and a risk of an increase in relative partial dispersion.
In the optical glass of embodiment 2, the contents of PbO, cdO, and As 2O3 are 0.01% or less, respectively. The upper limit of the contents of PbO, cdO and As 2O3 is preferably 0.005%, more preferably in the order of 0.003%, 0.002% and 0.001%, respectively. The content of PbO, cdO and As 2O3 is preferably small, but may be 0%. These components are components that may cause environmental burden, and preferably are substantially not contained.
The content and ratio of the glass components other than those described above in the optical glass according to embodiment 2 will be described in detail below.
In the optical glass of embodiment 2, the upper limit of the content of B 2O3 is preferably 20%, and more preferably 18%, 16%, 14%, 12%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1% in this order. In addition, when the content of B 2O3 is small, the content of B 2O3 may be 0%.
By setting the content of B 2O3 to the above range, the specific gravity of the glass can be reduced, and the thermal stability of the glass can be improved.
In the optical glass of embodiment 2, the upper limit of the content of P 2O5 is preferably 2.50%, more preferably in the order of 2.00%, 1.00%, 0.90%, 0.80%, 0.70%, 0.60%, 0.50%. The lower limit of the content of P 2O5 is preferably 0%, more preferably in the order of 0.05%, 0.10%, 0.12%, 0.14%, 0.16%, 0.18%, 0.20%. The content of P 2O5 may also be 0%. Since P 2O5 is a glass network forming component, the thermal stability of the glass can be improved by making the content thereof satisfy the lower limit described above. On the other hand, since P 2O5 is a component that reduces the dispersion and increases Δpg, F' relatively, the content of P 2O5 is set to the upper limit, and thus the reduction of dispersion can be suppressed and the thermal stability of the glass can be maintained.
In the optical glass of embodiment 2, the upper limit of the content of Al 2O3 is preferably 20%, and more preferably 15%, 13%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3% in this order. The content of Al 2O3 may be 0%. By setting the content of Al 2O3 to the above range, the devitrification resistance and thermal stability of the glass can be maintained.
In the optical glass of embodiment 2, the upper limit of the total content [ SiO 2+P2O5 ] of SiO 2 and P 2O5 is preferably 40%, and more preferably 39%, 38%, 37%, 36%, 35%, 34%. The lower limit of the total content [ SiO 2+P2O5 ] is preferably 10%, more preferably in the order of 15%, 20%, 22%, 24%, 26%, 28%, 30%. By setting the total content [ SiO 2+P2O5 ] to the above range, the rise of the relative partial dispersion Pg, F can be suppressed, and the thermal stability of the glass can be maintained.
In the optical glass of embodiment 2, the upper limit of the total content [ SiO 2+B2O3+P2O5 ] of SiO 2、P2O5 and B 2O3 is preferably 40%, and more preferably 39%, 38%, 37%, 36%, 35%, 34%. The lower limit of the total content [ SiO 2+B2O3+P2O5 ] is preferably 10%, more preferably in the order of 15%, 20%, 22%, 24%, 26%, 28%, 30%.
In the optical glass of embodiment 2, the upper limit of the mass ratio [ P 2O5/(SiO2+P2O5) ] of the content of P 2O5 to the total content of SiO 2 and P 2O5 is preferably 0.200, and more preferably in the order of 0.100, 0.050, 0.030, 0.020, 0.018, and 0.015. The mass ratio [ P 2O5/(SiO2+P2O5) ] may also be 0.
By setting the mass ratio [ P 2O5/(SiO2+P2O5) ] to the above range, the increase in the relative partial dispersion Pg, F can be suppressed.
In the optical glass of embodiment 2, the upper limit of the mass ratio [ P 2O5/(SiO2+B2O3+P2O5) ] of the content of P 2O5 to the total content of SiO 2、P2O5 and B 2O3 is preferably 0.200, and more preferably in the order of 0.100, 0.050, 0.030, 0.020, 0.018, and 0.015. The mass ratio [ P 2O5/(SiO2+B2O3+P2O5) ] may also be 0.
In the optical glass of embodiment 2, the upper limit of the mass ratio [ SiO 2/(SiO2+B2O3+P2O5 ] of the content of SiO 2 to the total content of SiO 2、P2O5 and B 2O3 is preferably 1. The lower limit of the mass ratio [ SiO 2/(SiO2+B2O3+P2O5) ] is preferably 0.900, more preferably in the order of 0.905, 0.910, 0.915, and 0.920.
In the optical glass of embodiment 2, the lower limit of the total content [ Nb 2O5+TiO2 ] of Nb 2O5 and TiO 2 is preferably 30%, and more preferably 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%. The upper limit of the total content [ Nb 2O5+TiO2 ] is preferably 55%, and more preferably 53%, 51%, 49%, 47%, 45%, 44%, 43%. By making the total content [ Nb 2O5+TiO2 ] within the above range, a desired optical constant can be achieved.
In the optical glass of embodiment 2, the upper limit of the mass ratio [ P 2O5/Nb2O5 ] of the content of P 2O5 to the content of Nb 2O5 is preferably 0.200, and more preferably in the order of 0.100, 0.050, 0.020, 0.018, 0.015, 0.014, 0.013, and 0.012. The mass ratio [ P 2O5/Nb2O5 ] may also be 0. By setting the mass ratio [ P 2O5/Nb2O5 ] to the above range, the increase in ΔPg, F' can be suppressed.
In the optical glass of embodiment 2, the upper limit of the mass ratio [ P 2O5/(Nb2O5+TiO2) ] of the content of P 2O5 to the total content of Nb 2O5 and TiO 2 is preferably 0.200, and more preferably in the order of 0.100, 0.050, 0.020, 0.018, 0.015, 0.014, 0.013, 0.012, 0.011, 0.010. The mass ratio [ P 2O5/(Nb2O5+TiO2) ] may also be 0. By setting the mass ratio [ P 2O5/(Nb2O5+TiO2) ] to the above range, the increase in ΔPg, F' can be suppressed.
In the optical glass of embodiment 2, the upper limit of the content of WO 3 is preferably 5.0%, more preferably in the order of 4.0%, 3.0%, 2.0%, 1.5%, 1.0%, 0.5%, 0.3%, 0.1%. In addition, the lower limit of the content of WO 3 is preferably 0%. The content of WO 3 may also be 0%. By setting the upper limit of the content of WO 3 to the above range, the transmittance can be improved, and the relative partial dispersions Pg, F and specific gravity can be reduced.
In the optical glass of embodiment 2, the upper limit of the content of Bi 2O3 is 5.0%, and more preferably 4.0%, 3.0%, 2.0%, 1.5%, 1.0%, 0.5%, 0.3%, and 0.1% are more preferable. The lower limit of the content of Bi 2O3 is preferably 0%. The content of Bi 2O3 may be 0%. By setting the content of Bi 2O3 to the above range, the thermal stability of the glass can be improved, and the relative partial dispersions Pg, F and specific gravity can be reduced.
In the optical glass of embodiment 2, the lower limit of the total content [ Nb 2O5+TiO2+WO3+Bi2O3 ] of Nb 2O5、TiO2、WO3 and Bi 2O3 is preferably 30%, and more preferably 32%, 34%, 36%, 38%, 39%, 40%. The upper limit of the total content [ Nb 2O5+TiO2+WO3+Bi2O3 ] is preferably 55%, and more preferably 53%, 51%, 50%, 49%, 48%, 47%, 46%, 45%, 44%, 43% in this order. By making the total content [ Nb 2O5+TiO2+WO3+Bi2O3 ] within the above range, a desired optical constant can be achieved.
In the optical glass of embodiment 2, the lower limit of the mass ratio [ Nb 2O5/(Nb2O5+TiO2+WO3+Bi2O3) ] of the content of Nb 2O5 to the total content of Nb 2O5、TiO2、WO3 and Bi 2O3 is preferably 0.500, and more preferably in the order of 0.5500, 0.600, 0.650, 0.700, 0.750, 0.800, 0.820, 0.840, and 0.850. The upper limit of the mass ratio is preferably 1.000, and more preferably 0.999, 0.998, 0.997, 0.996, and 0.995 in this order.
In the optical glass of embodiment 2, the lower limit of the mass ratio [ ZrO 2/(Nb2O5+TiO2+WO3+Bi2O3) ] of the content of ZrO 2 to the total content of Nb 2O5、TiO2、WO3 and Bi 2O3 is preferably 0.05, and more preferably in the order of 0.07, 0.09, 0.11, 0.13, 0.15, 0.17, and 0.18. The upper limit of the mass ratio is preferably 0.40, more preferably in the order of 0.39, 0.38, 0.37, 0.36, 0.35, 0.34, 0.33, 0.32. By setting the mass ratio to the above range, the abbe number vd and the relative partial dispersion Pg, F can be controlled.
In the optical glass of embodiment 2, the lower limit of the mass ratio [(SiO2+B2O3+P2O5)/(Nb2O5+TiO2+WO3+Bi2O3)] of the total content of SiO 2、P2O5 and B 2O3 to the total content of Nb 2O5、TiO2、WO3 and Bi 2O3 is preferably 0.400, and more preferably in the order of 0.450, 0.500, 0.550, 0.600, 0.650, 0.670, 0.680, 0.690, and 0.700. The upper limit of the mass ratio is preferably 1.000, more preferably in the order of 0.980, 0.960, 0.940, 0.920, 0.900, 0.890, 0.880, 0.870, 0.860, 0.850, 0.840. By setting the mass ratio to the above range, the abbe number vd and the relative partial dispersion Pg, F can be controlled.
In the optical glass of embodiment 2, the upper limit of the content of Li 2 O is preferably 10%, more preferably in the order of 9%, 8%, 7%, 6%. The lower limit of the content of Li 2 O is preferably 0%, more preferably in the order of 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%. By setting the content of Li 2 O to the above range, the increase in the relative partial dispersions Pg, F can be suppressed, and the chemical durability, weather resistance, and stability at reheating can be maintained.
In the optical glass of embodiment 2, the upper limit of the Na 2 O content is preferably 30%, and more preferably 25%, 23%, 21%, 19%, 17%, 15%, and 13% are further in this order. The lower limit of the Na 2 O content is preferably 0%, more preferably in the order of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%. By setting the Na 2 O content to the above range, the relative partial dispersions Pg, F can be reduced.
In the optical glass of embodiment 2, the upper limit of the content of K 2 O is preferably 30%, and more preferably 25%, 20%, 15%, 10%, 8%, 6%, 4%, and 2% are further in this order. The lower limit of the content of K 2 O is preferably 0%, more preferably in the order of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%. By setting the content of K 2 O to the above range, the thermal stability of the glass can be improved.
In the optical glass of embodiment 2, the upper limit of the content of Cs 2 O is preferably 10%, and more preferably in the order of 8%, 6%, 5%, 4%, 3%, 2%, and 1%. The lower limit of the content of Cs 2 O is preferably 0%. The content of Cs 2 O may also be 0%.
Cs 2 O has an effect of improving the thermal stability of the glass, but when the content thereof is increased, chemical durability and weather resistance are reduced. But also has the hidden trouble of increasing specific gravity. Therefore, each content of Cs 2 O is preferably in the above range.
In the optical glass of embodiment 2, the upper limit of the total content [ Li 2O+Na2O+K2O+Cs2 O ] of Li 2O、Na2O、K2 O and Cs 2 O is preferably 40%, and more preferably 35%, 30%, 28%, 26%, 24%, 22%, 21%, 20%, 19%. The lower limit of the total content [ Li 2O+Na2O+K2O+Cs2 O ] is preferably 3%, more preferably in the order of 5%, 7%, 9%, 10%, 11%, 12%, 13%, 14%. By setting the total content [ Li 2O+Na2O+K2O+Cs2 O ] to the above range, the meltability and thermal stability of the glass can be improved, and the liquid phase temperature can be reduced.
In the optical glass of embodiment 2, the upper limit of the mass ratio [(Li2O+Na2O+K2O+Cs2O)/(SiO2+B2O3+P2O5)] of the total content of Li 2O、Na2O、K2 O and Cs 2 O to the total content of SiO 2、P2O5 and B 2O3 is preferably 5.000, and more preferably in the order of 3.000、2.000、1.500、1.300、1.100、1.000、0.900、0.800、0.780、0.760、0.740、0.720、0.700、0.680、0.660、0.640、0.620、0.600. The lower limit of the mass ratio is preferably 0.100, more preferably in the order of 0.200, 0.300, 0.350, 0.400, 0.420, 0.440, 0.460, 0.480. If the mass ratio is too low, there is a risk that the melting property will be poor and the relative partial dispersion Pg, F will increase, and if it is too high, there is a risk that the glass stability will be lowered.
In the optical glass of embodiment 2, the upper limit of the mass ratio [(Li2O+Na2O+K2O+Cs2O)/(Nb2O5+TiO2+WO3+Bi2O3)] of the total content of Li 2O、Na2O、K2 O and Cs 2 O to the total content of Nb 2O5、TiO2、WO3 and Bi 2O3 is preferably 4.000, and more preferably in the order of 3.000, 2.000, 1.000, 0.900, 0.800, 0.750, 0.700, 0.650, 0.600, 0.550, 0.520, 0.500, 0.490, 0.480, and 0.470. The lower limit of the mass ratio is preferably 0.100, more preferably in the order of 0.150, 0.200, 0.240, 0.260, 0.280, 0.300, 0.310, 0.320, 0.330. If the mass ratio is too low, there is a possibility that the relative partial dispersion Pg, F increases and the transmittance becomes poor, and if it is too high, there is a possibility that the glass stability is lowered.
In the optical glass of embodiment 2, the upper limit of the mass ratio [ P 2O5/(Li2O+Na2O+K2O+Nb2O5) ] of the content of P 2O5 to the total content of Li 2O、Na2O、K2 O and Nb 2O5 is preferably 0.500, and more preferably in the order of 0.300, 0.100, 0.090, 0.080, 0.050, 0.030, 0.020, 0.015, 0.013, 0.011, 0.010, 0.009, and 0.008. The mass ratio [ P 2O5/(Li2O+Na2O+K2O+Nb2O5) ] may also be 0. By setting the mass ratio to the above range, the increase in Δpg, F' can be suppressed.
In the optical glass of embodiment 2, the upper limit of the mass ratio [P2O5/(Li2O+Na2O+K2O+Cs2O+Nb2O5+TiO2+WO3+Bi2O3)] of the content of P 2O5 to the total content of Li 2O、Na2O、K2O、Cs2O、Nb2O5、TiO2、WO3 and Bi 2O3 is preferably 0.500, and more preferably in the order of 0.300, 0.100, 0.090, 0.080, 0.050, 0.030, 0.020, 0.015, 0.013, 0.011, 0.010, 0.009, and 0.008. The mass ratio may also be 0. By setting the mass ratio to the above range, the increase in Δpg, F' can be suppressed.
In the optical glass of embodiment 2, the upper limit of the MgO content is preferably 20%, and more preferably 15%, 10%, 8%, 7%, 6%, 5%, 4%, 3%, and 2% in this order. The lower limit of the MgO content is preferably 0%. The MgO content may be 0%.
In the optical glass according to embodiment 2, the upper limit of the CaO content is preferably 20%, and more preferably 15%, 10%, 8%, 7%, 6%, 5%, 4%, 3%, and 2% in this order. The lower limit of the CaO content is preferably 0%. The CaO content may be 0%.
In the optical glass of embodiment 2, the upper limit of the content of SrO is preferably 20%, and more preferably 15%, 10%, 8%, 7%, 6%, 5%, 4%, 3%, and 2% in this order. The lower limit of the SrO content is preferably 0%. The SrO content may be 0%.
In the optical glass according to embodiment 2, the upper limit of the content of BaO is preferably 20%, and more preferably 15%, 10%, 8%, 7%, 6%, 5%, 4%, 3%, and 2% in this order. In addition, when the content of BaO is small, the content of BaO may be 0%.
MgO, caO, srO, baO are glass components having an effect of improving the thermal stability and devitrification resistance of the glass. However, when the content of these glass components increases, the specific gravity increases, high dispersibility is impaired, and the thermal stability and devitrification resistance of the glass decrease. Therefore, the respective contents of these glass components are preferably within the above ranges.
In the optical glass of embodiment 2, the upper limit of the total content of MgO and CaO [ mgo+cao ] is preferably 20%, and more preferably 15%, 10%, 8%, 7%, 6%, 5%, 4%, 3%, 2%. The lower limit of the total content [ MgO+CaO ] is preferably 0%. The total content [ MgO+CaO ] may be 0%. By setting the total content [ MgO+CaO ] to the above range, the thermal stability can be maintained without impeding the high dispersion.
In the optical glass according to embodiment 2, the upper limit of the ZnO content is preferably 20%, and more preferably 15%, 10%, 8%, 7%, 6%, 5%, 4%, 3%, and 2% are further in this order. The lower limit of the ZnO content is preferably 0%. The ZnO content may be 0%.
ZnO is a glass component having an effect of improving the thermal stability of glass. However, if the content of ZnO is too large, the specific gravity increases. Therefore, the content of ZnO is preferably in the above range from the viewpoint of improving the thermal stability of the glass and maintaining a desired optical constant.
In the optical glass of embodiment 2, the upper limit of the total content [ mgo+cao+sro+bao+zno ] of MgO, caO, srO, baO and ZnO is preferably 20%, and more preferably 15%, 10%, 8%, 7%, 6%, 5%, 4%, 3%, 2%. The lower limit of the total content is preferably 0%. The total content may also be 0%. By setting the total content to the above range, an increase in specific gravity can be suppressed, and thermal stability can be maintained without impeding high dispersion.
In the optical glass of embodiment 2, the upper limit of the mass ratio [ (mgo+cao+sro+bao+zno)/(Li 2O+Na2O+K2O+Cs2 O) ] of the total content of MgO, caO, srO, baO and ZnO to the total content of Li 2O、Na2O、K2 O and Cs 2 O is preferably 20.000, and more preferably in the order of 15.000、10.000、7.000、5.000、3.000、2.000、1.000、0.900、0.800、0.700、0.600、0.500、0.400、0.300、0.200、0.100、0.050、0.030. The lower limit of the mass ratio is preferably 0. The mass ratio may also be 0.
In the optical glass of embodiment 2, the upper limit of the content of La 2O3 is preferably 20%, and more preferably 15%, 12%, 10%, 8%, 7%, 6%, 5%, 4%, 3%, 2% in this order. The lower limit of the content of La 2O3 is preferably 0%, and the content of La 2O3 may be 0%. By setting the content of La 2O3 to the above range, a desired optical constant can be achieved, an increase in specific gravity can be suppressed, and relative partial dispersions Pg, F can be reduced.
In the optical glass of embodiment 2, the upper limit of the content of Y 2O3 is preferably 20%, and more preferably 18%, 16%, 15%, 14%, 13%, 12%, 10%, 9%, 8% in this order. The lower limit of the content of Y 2O3 is preferably 0%.
When the content of Y 2O3 is too large, the thermal stability of the glass is lowered, and the glass is easily devitrified during production. Therefore, the content of Y 2O3 is preferably in the above range from the viewpoint of suppressing the decrease in the thermal stability of the glass.
In the optical glass of embodiment 2, the upper limit of the content of Ta 2O5 is preferably 20%, and more preferably 15%, 12%, 10%, 8%, 7%, 6%, 5%, 4%, 3%, 2% in this order. The lower limit of the content of Ta 2O5 is preferably 0%.
Ta 2O5 is a glass component having an effect of improving the thermal stability of glass, and is a component that causes the relative partial dispersion Pg, F to decrease. On the other hand, when the content of Ta 2O5 is increased, the thermal stability of the glass is lowered, and melting residues of the glass raw material are likely to occur when the glass is melted. And, the specific gravity increases. And the cost of raw materials increases. Therefore, the content of Ta 2O5 is preferably in the above range.
In the optical glass of embodiment 2, the content of Sc 2O3 is preferably 2% or less. The lower limit of the content of Sc 2O3 is preferably 0%.
In the optical glass of embodiment 2, the content of HfO 2 is preferably 2% or less. The lower limit of the content of HfO 2 is preferably 0%, more preferably in the order of 0.05% and 0.1%.
Sc 2O3、HfO2 is an expensive component having an effect of improving the high dispersibility of glass. Therefore, each content of Sc 2O3、HfO2 is preferably within the above range.
In the optical glass of embodiment 2, the content of Lu 2O3 is preferably 2% or less. The lower limit of the content of Lu 2O3 is preferably 0%.
Lu 2O3 has an effect of improving high dispersibility of glass, but is also a glass component that causes an increase in specific gravity of glass because of a large molecular weight. Therefore, the content of Lu 2O3 is preferably in the above range.
In the optical glass of embodiment 2, the content of GeO 2 is preferably 2% or less. The lower limit of the content of GeO 2 is preferably 0%.
GeO 2 has an effect of improving high dispersibility of glass, but is an extremely expensive component among commonly used glass components. Therefore, the content of GeO 2 is preferably in the above range from the viewpoint of reducing the manufacturing cost of the glass.
In the optical glass of embodiment 2, the content of Gd 2O3 is preferably 2% or less. The lower limit of the content of Gd 2O3 is preferably 0%.
When the content of Gd 2O3 is too large, the heat stability of the glass is lowered. When the content of Gd 2O3 is too large, the specific gravity of the glass increases. In addition, the cost of raw materials increases. Therefore, the content of Gd 2O3 is preferably in the above range from the viewpoint of keeping the thermal stability of the glass well and suppressing the increase of specific gravity.
In the optical glass of embodiment 2, the content of Yb 2O3 is preferably 2% or less. The lower limit of the Yb 2O3 content is preferably 0%.
Since Yb 2O3 has a larger molecular weight than La 2O3、Gd2O3、Y2O3, the specific gravity of the glass increases. Therefore, it is preferable to reduce the content of Yb 2O3 to suppress an increase in specific gravity of the glass.
In addition, when the content of Yb 2O3 is too large, the thermal stability of the glass is lowered. The content of Yb 2O3 is preferably in the above range from the viewpoint of preventing a decrease in the thermal stability of the glass and suppressing an increase in specific gravity.
The optical glass of embodiment 2 is preferably composed mainly of the glass component, that is, siO 2、Nb2O5、ZrO2 as an essential component, B2O3、P2O5、Al2O3、TiO2、WO3、Bi2O3、Li2O、Na2O、K2O、Cs2O、MgO、CaO、SrO、BaO、ZnO、La2O3、Y2O3、Ta2O5、Sc2O3、HfO2、Lu2O3、GeO2、Gd2O3 and Yb 2O3 as optional components, and the total content of the glass component is preferably more than 95%, more preferably more than 98%, still more preferably more than 99%, still more preferably more than 99.5%.
The optical glass of embodiment 2 is preferably composed of the above glass component, but may contain other components within a range that does not interfere with the operational effect of embodiment 2. In addition, in the invention of claim 2, the inclusion of unavoidable impurities is not excluded.
(Other Components)
The optical glass of embodiment 2 may contain a small amount of Sb 2O3、CeO2 or the like as a refining agent. The total amount of the clarifying agent (external proportion addition amount) is preferably set to 0% or more and less than 1%, more preferably set to 0% or more and 0.5% or less.
The external ratio added amount is a value expressed as weight percentage of the added amount of the fining agent when the total content of all glass components except the fining agent is set to 100%.
The optical glass can obtain high transmittance in a wide range of a visible region. In order to effectively use such features, it is preferable that the coloring element is not contained. As elements of colorability, cu, co, ni, fe, cr, eu, nd, er, V and the like can be exemplified. The content of any element is preferably less than 100 mass ppm, more preferably 0 to 80 mass ppm, still more preferably 0 to 50 mass ppm, and particularly preferably substantially no element.
Ga, te, tb, and the like are components that do not require introduction, and are also expensive components. Accordingly, the content of Ga 2O3、TeO2、TbO2 in mass% is preferably 0 to 0.1%, more preferably 0 to 0.05%, still more preferably 0 to 0.01%, still more preferably 0 to 0.005%, still more preferably 0 to 0.001%, and particularly preferably substantially no content.
(Glass characteristics)
< Refractive index nd >)
In the optical glass of embodiment 2, the refractive index nd is preferably 1.70 to 1.90. The refractive index nd may be set to 1.72 to 1.85, or 1.73 to 1.83. The component that relatively increases the refractive index nd is Nb 2O5、TiO2、ZrO2、Ta2O5、La2O3. The component that relatively lowers the refractive index nd is SiO 2、B2O3、Li2O、Na2O、K2 O. By properly adjusting the content of these components, the refractive index nd can be controlled.
< Relative partial Dispersion Pg, F >)
The upper limit of the relative partial dispersion Pg, F of the optical glass of embodiment 2 is preferably 0.6500, and more preferably 0.6400, 0.6300, 0.6200, 0.6100, 0.6050, 0.6040, 0.6030, 0.6020, 0.6010, and 0.6000 are further in this order. The lower limit of the relative partial dispersion Pg, F is preferably 0.5500, and may be 0.5600, 0.5700, 0.5800, 0.5840, 0.5850, 0.5870, 0.5890, 0.5900, 0.5910, 0.5920, 0.5930, 0.5940.
By setting the relative partial dispersion Pg, F to the above range, an optical glass suitable for high-order chromatic aberration correction can be obtained. The component of the relative partial dispersion Pg, F is Nb 2O5、TiO2、ZrO2、Ta2O5, which is relatively high. The relative partial dispersion Pg, F is relatively reduced and the component of the F is SiO 2、B2O3、Li2O、Na2O、K2 O. By properly adjusting the content of these components, the relative partial dispersion Pg, F can be controlled.
In the optical glass of embodiment 2, the relative partial dispersion Pg, F preferably satisfies the following formula (2-1), more preferably satisfies the following formula (2-2), still more preferably satisfies the following formula (2-3), and particularly preferably satisfies the following formula (2-4). By making the relative partial dispersion Pg, F satisfy the following expression, an optical glass suitable for secondary chromatic aberration correction can be provided.
Pg,F≤-0.00286×νd+0.68900···(2-1)
Pg,F≤-0.00286×νd+0.68800···(2-2)
Pg,F≤-0.00286×νd+0.68600···(2-3)
Pg,F≤-0.00286×νd+0.68400···(2-4)
The upper limit of Δpg, F' of the optical glass according to embodiment 2 is preferably 0.0000, and more preferably-0.0010, -0.0020, -0.0030, -0.0040, -0.0050, and-0.0060. Further, the lower the Δpg, the more preferable, the lower limit thereof is preferably-0.0200, further by-0.0180, -0.0160, -0.0140, -0.0130, -0.0120. The component of Δpg, F' is relatively increased to P 2O5、B2O3、TiO2. The components of Δpg, F 'are relatively reduced to Nb2O5、La2O3、Y2O3、ZrO2、Li2O、Na2O、K2O., and Δpg, F' can be controlled by appropriately adjusting the content of these components.
< Specific gravity of glass >
The specific gravity of the optical glass according to embodiment 2 is preferably 3.60 or less, more preferably 3.55 or less, 3.50 or less, 3.48 or less, 3.46 or less, 3.45 or less, 3.44 or less, 3.43 or less, 3.42 or less, 3.41 or less, and 3.40 or less. The lower limit is not particularly limited as the specific gravity is smaller, but is generally about 3.00. The components that relatively increase the specific gravity are BaO, la 2O3、ZrO2、Nb2O5、Ta2O5, and the like. The component that relatively reduces the specific gravity is SiO 2、B2O3、Li2O、Na2O、K2 O or the like. The specific gravity can be controlled by adjusting the content of these components.
< Glass transition temperature Tg >)
The upper limit of the glass transition temperature Tg of the optical glass according to embodiment 2 is preferably 700℃and more preferably 670℃650℃630℃620℃610℃600℃590 ℃. The lower limit of the glass transition temperature Tg is preferably 450℃and more preferably 470℃and 500℃and 510℃and 520℃and 530℃and 540 ℃. The component that relatively lowers the glass transition temperature Tg is Li 2O、Na2O、K2 O or the like. The component that relatively increases the glass transition temperature Tg is La 2O3、ZrO2、Nb2O5 or the like. By properly adjusting the content of these components, the glass transition temperature Tg can be controlled.
Light transmittance of glass
The optical glass of embodiment 2 can be evaluated for light transmittance by the coloring degrees λ70 and λ5.
For a glass sample having a thickness of 10.0 mm.+ -. 0.1mm, the spectral transmittance was measured in the wavelength range of 200 to 700nm, the wavelength at which the external transmittance reached 70% was represented by λ70, and the wavelength at which the external transmittance reached 5% was represented by λ5.
The optical glass according to embodiment 2 has a lambda 70 of preferably 500nm or less, more preferably 470nm or less, still more preferably 450nm or less, and still more preferably 430nm or less. Also, λ5 is preferably 400nm or less, more preferably 380nm or less, and still more preferably 370nm or less. The coloring degrees λ70 and λ5 can be controlled by adjusting the content of ZrO 2、Nb2O5、TiO2、SiO2、B2O3.
< Stability upon reheat >
The optical glass of embodiment 2 preferably does not cause clouding when heated in a test furnace set at a temperature 200 to 220 ℃ higher than the glass transition temperature Tg for 5 minutes. More preferably, the number of crystals deposited by the heating is 100 or less per 1 sample. Stability upon reheating can be controlled by adjusting the Nb2O5、TiO2、SiO2、B2O3、Li2O、Na2O、K2O、P2O5 content.
Stability upon reheating was measured as follows. After heating a glass sample having a size of 10mm×10mm×7.5mm in a test furnace set to a temperature 200 to 220 ℃ higher than the glass transition temperature Tg of the glass sample for 5 minutes, the number of crystals corresponding to each sample was measured by an optical microscope (observation magnification: 40 to 200 times). In addition, the presence or absence of cloudiness of the glass was visually confirmed.
The optical glass according to embodiment 2 can be produced in the same manner as in embodiment 1. The optical element and the like may be manufactured in the same manner as in embodiment 1.
Invention 3
[ Background of the invention 3 ]
Patent document 3-1 discloses an optical glass having a refractive index nd of 1.674 or more and an abbe number vd of 30.2 or more. However, the optical glass described in patent document 3-1 has low homogeneity, and does not satisfy the conditions of low specific gravity and low Pg, F. Accordingly, there is a need for an optical glass having a desired optical constant and having higher performance.
[ Prior Art document of the invention 3 ]
Patent literature
Patent document 3-1: japanese patent laid-open No. 2017-105702
[ 3 Rd summary ]
[ Problem to be solved by the invention 3 ]
In order to reduce power consumption when the autofocus function is driven, the optical element mounted in the autofocus optical system is required to be lightweight. If the specific gravity of the glass can be reduced, the weight of the optical element such as a lens can be reduced. In addition, for correction of chromatic aberration, the relative partial dispersion Pg, F is required to be small.
Accordingly, an object of the invention of claim 3 is to provide an optical glass having a desired optical constant, a relatively small specific gravity, and small relative partial dispersion Pg, F, and an optical element formed of the optical glass.
[ Means of solving the problems ]
The gist of the invention of claim 3 is as follows.
(1) An optical glass, wherein,
The mass ratio of the content of SiO 2 to the content of Nb 2O5 [ SiO 2/Nb2O5 ] is more than 1.05,
The mass ratio [ ZrO 2/Nb2O5 ] of the content of ZrO 2 relative to the content of Nb 2O5 is more than 0.25,
The mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is greater than 0.65,
The total content of TiO 2 and BaO [ TiO 2 +BaO ] is less than 10 mass%,
And the optical glass satisfies 1 or more of the following (a) and (b):
(a) The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 9 mass%,
(B) The mass ratio of the total content R 2 O to the total content of the total content R 2 O and the total content R ' O [ R 2O/(R2 O+R ' O) ] is greater than 0.6, the total content R 2 O being the total content of Li 2O、Na2 O and K 2 O, the total content R ' O being the total content of MgO, caO, srO and BaO.
(2) An optical glass, wherein,
The mass ratio of the content of SiO 2 to the content of Nb 2O5 [ SiO 2/Nb2O5 ] is more than 1.05,
The mass ratio [ ZrO 2/Nb2O5 ] of the content of ZrO 2 relative to the content of Nb 2O5 is more than 0.25,
The mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is greater than 0.65,
The total content of TiO 2 and BaO [ TiO 2 +BaO ] is less than 10 mass%,
The mass ratio of the content of Ta 2O5 to the total content of TiO 2 and Nb 2O5 [ Ta 2O5/(TiO2+Nb2O5) ] is less than 0.3,
And the optical glass satisfies 1 or more of the following (c) and (d):
(c) The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 1.1 mass%,
(D) The mass ratio of the total content R 2 O to the total content of the total content R 2 O and the total content R ' O [ R 2O/(R2 O+R ' O) ] is greater than 0.05, the total content R 2 O being the total content of Li 2O、Na2 O and K 2 O, the total content R ' O being the total content of MgO, caO, srO and BaO.
(3) An optical glass, wherein,
The mass ratio of the content of SiO 2 to the content of Nb 2O5 [ SiO 2/Nb2O5 ] is more than 1.05,
The mass ratio [ ZrO 2/Nb2O5 ] of the content of ZrO 2 relative to the content of Nb 2O5 is more than 0.25,
The mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is greater than 0.65,
The total content of TiO 2 and BaO [ TiO 2 +BaO ] is less than 10 mass%,
The mass ratio of the content of ZnO to the content of Nb 2O5 [ ZnO/Nb 2O5 ] is less than 0.14,
And the optical glass satisfies 1 or more of the following (e) and (f):
(e) The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 1.1 mass%,
(F) The mass ratio of the total content R 2 O to the total content of the total content R 2 O and the total content R ' O [ R 2O/(R2 O+R ' O) ] is greater than 0.05, the total content R 2 O being the total content of Li 2O、Na2 O and K 2 O, the total content R ' O being the total content of MgO, caO, srO and BaO.
(4) An optical glass having an Abbe number vd of 30 to 36,
The specific gravity is not more than 3.19,
The relative partial dispersion Pg, F has a deviation ΔPg, F of 0.0015 or less.
(5) An optical element formed of the optical glass according to any one of the above (1) to (4).
[ 3 Rd invention ] Effect of (2)
According to the invention of claim 3, an optical glass having a desired optical constant, a relatively small specific gravity, and small relative partial dispersions Pg and F, and an optical element formed of the optical glass can be provided.
[ Embodiment of the invention 3 ]
The optical glass according to embodiment 3 will be described below as embodiment 3-1, embodiment 3-2, embodiment 3-3 and embodiment 3-4. The actions and effects of the respective glass components in embodiments 3-2, 3-3 and 3-4 are the same as those of the respective glass components in embodiment 3-1. Therefore, in embodiments 3-2, 3-3, and 3-4, the repetitive description of embodiment 3-1 will be omitted as appropriate.
In embodiments 3-1, 3-2, 3-3 and 3-4, the relative partial dispersion Pg, F is expressed by using the refractive indices ng, nF and nC in g-rays, F-rays and C-rays as follows.
Pg,F＝(ng-nF)/(nF-nC)
In a plane where the horizontal axis is the abbe number vd and the vertical axis is the relative partial dispersion Pg, F, the normal line is expressed by the following formula.
Pg,F(0)＝0.6483-(0.0018×νd)
The deviation Δpg, F of the relative partial dispersion Pg, F with respect to the normal line is expressed as follows.
ΔPg,F＝Pg,F-Pg,F(0)
Embodiment 3-1
With respect to the optical glass of embodiment 3-1,
The mass ratio of the content of SiO 2 to the content of Nb 2O5 [ SiO 2/Nb2O5 ] is more than 1.05,
The mass ratio [ ZrO 2/Nb2O5 ] of the content of ZrO 2 relative to the content of Nb 2O5 is more than 0.25,
The mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is greater than 0.65,
The total content of TiO 2 and BaO [ TiO 2 +BaO ] is less than 10 mass%,
Further, it satisfies 1 or more of the following (a) and (b):
(a) The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 9 mass%,
(B) The mass ratio of the total content R 2 O to the total content of the total content R 2 O and the total content R ' O [ R 2O/(R2 O+R ' O) ] is greater than 0.6, the total content R 2 O being the total content of Li 2O、Na2 O and K 2 O, the total content R ' O being the total content of MgO, caO, srO and BaO.
In the optical glass of embodiment 3-1, the mass ratio [ SiO 2/Nb2O5 ] of the content of SiO 2 to the content of Nb 2O5 is more than 1.05. The lower limit of the mass ratio [ SiO 2/Nb2O5 ] is preferably 1.09, more preferably in the order of 1.11, 1.15, 1.17. The upper limit of the mass ratio [ SiO 2/Nb2O5 ] is preferably 2.10, more preferably in the order of 2.05, 2.00, and 1.95. By setting the mass ratio [ SiO 2/Nb2O5 ] to the above range, the specific gravity of the glass can be reduced while maintaining desired optical constants (refractive index nd, abbe number vd).
In the optical glass of embodiment 3-1, the mass ratio [ ZrO 2/Nb2O5 ] of the content of ZrO 2 relative to the content of Nb 2O5 is more than 0.25. The lower limit of the mass ratio [ ZrO 2/Nb2O5 ] is preferably 0.26, and more preferably in the order of 0.27, 0.28, 0.29, 0.30, 0.305, 0.310, 0.315. The upper limit of the mass ratio [ ZrO 2/Nb2O5 ] is preferably 0.65, and more preferably in the order of 0.61, 0.57, and 0.53. By setting the lower limit of the mass ratio [ ZrO 2/Nb2O5 ] to the above range, the relative partial dispersions Pg, F can be reduced, the raw material cost can be reduced, and the desired optical constant and solubility can be maintained.
In the optical glass of embodiment 3-1, the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is more than 0.65. The lower limit of the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] is preferably 0.66, more preferably in the order of 0.67, 0.70, 0.73, 0.76, 0.80, 0.83, 0.86, 0.88. The upper limit of the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] is preferably 1.20, more preferably in the order of 1.14, 1.12, and 1.10. By setting the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] to the above range, the thermal stability of the glass can be maintained, and a desired optical constant can be obtained.
In the optical glass of embodiment 3-1, the total content of TiO 2 and BaO [ TiO 2 +BaO ] is less than 10%. The upper limit of the total content [ TiO 2 +BaO ] is preferably 8.0%, more preferably in the order of 7.8%, 7.6%, 7.4%. The lower limit of the total content [ Ti 2 +BaO ] is preferably 0%, more preferably in the order of 1%, 2% and 3%. By setting the upper limit of the total content [ Ti 2 +BaO ] to the above range, the relative partial dispersions Pg, F can be reduced, and the specific gravity of the glass can be reduced.
The optical glass according to embodiment 3-1 satisfies 1 or more of the following (a) and (b):
(a) The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 9 percent,
(B) The mass ratio of the total content R 2 O to the total content of the total content R 2 O and the total content R ' O [ R 2O/(R2 O+R ' O) ] is greater than 0.6, the total content R 2 O being the total content of Li 2O、Na2 O and K 2 O, the total content R ' O being the total content of MgO, caO, srO and BaO.
That is, in the optical glass of embodiment 3-1, the total content R 2 O of Li 2O、Na2 O and K 2 O may be more than 9%. The lower limit of the total content R 2 O is preferably 15.0%, more preferably in the order of 15.5%, 16.0%, 16.5%. The upper limit of the total content R 2 O is preferably 22.0%, more preferably in the order of 21.7%, 21.4%, 21.1%. By setting the total content R 2 O to the above range, the specific gravity of the glass can be reduced, and the stability of the glass at reheating can be maintained.
In the optical glass according to embodiment 3-1, the mass ratio of the total content R 2 O [ R 2O/(R2 o+rj O ] to the total content R 2 O and MgO, caO, srO of Li 2O、Na2 O and K 2 O and the total content R' O of BaO may be more than 0.6. The lower limit of the mass ratio [ R 2O/(R2 O+R' O) ] is preferably 0.80, more preferably in the order of 0.82, 0.84, 0.86. The upper limit of the mass ratio [ R 2O/(R2 O+R' O) ] is preferably 0.95, more preferably in the order of 0.98, 0.99, and 1.00. By setting the mass ratio [ R 2O/(R2 O+R' O) ] to the above range, the specific gravity of the glass can be reduced, and the stability of the glass at the time of reheating can be maintained.
In the optical glass of embodiment 3-1, the mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] of the content of Ta 2O5 to the total content of TiO 2 and Nb 2O5 is preferably less than 0.3, and the upper limit thereof is more preferably in the order of 0.25, 0.20, 0.15. The lower limit of the mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] is preferably 0, and more preferably in the order of 0.05, 0.07, and 0.10. The mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] may also be 0. By setting the upper limit of the mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] to the above range, the specific gravity of glass can be reduced, and the raw material cost can be reduced.
In the optical glass of embodiment 3-1, the mass ratio [ ZnO/Nb 2O5 ] of the content of ZnO to the content of Nb 2O5 is preferably less than 0.14, and the upper limit thereof is more preferably in the order of 0.125, 0.115, and 0.105. The lower limit of the mass ratio [ ZnO/Nb 2O5 ] is preferably 0, and more preferably 0.02, 0.05, and 0.07. The mass ratio [ ZnO/Nb 2O5 ] may be 0. By setting the upper limit of the mass ratio [ ZnO/Nb 2O5 ] to the above range, the specific gravity of the glass can be reduced, and a desired optical constant can be obtained.
The content and ratio of the glass components other than those described above in the optical glass according to embodiment 3-1 will be described in detail below.
In the optical glass according to embodiment 3-1, the lower limit of the content of SiO 2 is preferably 25%, more preferably in the order of 28%, 30% and 32%. The upper limit of the content of SiO 2 is preferably 45%, and more preferably 43%, 41% and 39%. By setting the content of SiO 2 to the above range, the specific gravity of the glass can be reduced, and the stability at reheating of the glass and the desired optical constant can be obtained.
In the optical glass according to embodiment 3-1, the upper limit of the content of B 2O3 is preferably 5%, more preferably in the order of 4%, 3% and 2%. The lower limit of the content of B 2O3 is preferably 0%, more preferably in the order of 0.2%, 0.4%, and 0.6%. The content of B 2O3 may be 0%. By setting the content of B 2O3 to the above range, the specific gravity of the glass can be reduced, and the thermal stability of the glass can be improved.
In the optical glass of embodiment 3-1, the upper limit of the total content [ SiO 2+B2O3 ] of SiO 2 and B 2O3 is preferably 45%, and more preferably 43%, 41% and 39%. The lower limit of the total content [ SiO 2+B2O3 ] is preferably 25%, more preferably in the order of 28%, 30% and 32%. By setting the total content [ SiO 2+B2O3 ] to the above range, the specific gravity of the glass can be reduced, the thermal stability of the glass can be improved, and further a desired optical constant can be obtained.
In the optical glass according to embodiment 3-1, the upper limit of the content of P 2O5 is preferably 1.5%, more preferably in the order of 1.3%, 1.1% and 0.9%. The lower limit of the content of P 2O5 is preferably 0%, more preferably in the order of 0.1%, 0.2%, and 0.3%. The content of P 2O5 may be 0%. By setting the content of P 2O5 to the above range, an increase in the relative partial dispersion Pg, F can be suppressed, and the thermal stability of the glass can be maintained.
In the glass of embodiment 3-1, the upper limit of the content of Al 2O3 is preferably 5%, more preferably in the order of 4%, 3% and 2%. The content of Al 2O3 may be 0%. By setting the content of Al 2O3 to the above range, the devitrification resistance and thermal stability of the glass can be maintained.
In the optical glass according to embodiment 3-1, the upper limit of the content of TiO 2 is preferably 10%, more preferably in the order of 9.5%, 9.0% and 8.5%. The lower limit of the content of TiO 2 is preferably 0%. The content of TiO 2 may also be 0%. By making the content of TiO 2 within the above range, a desired optical constant can be achieved, and the raw material cost of the glass can be reduced.
In the optical glass according to embodiment 3-1, the lower limit of the content of Nb 2O5 is preferably 18%, more preferably in the order of 20%, 22% and 24%. The upper limit of the content of Nb 2O5 is preferably 38%, more preferably in the order of 35%, 33%, 31%. By setting the content of Nb 2O5 to the above range, a desired optical constant can be achieved, an increase in specific gravity can be suppressed, and relative partial dispersions Pg, F can be reduced.
In the optical glass according to embodiment 3-1, the lower limit of the total content [ TiO 2+Nb2O5 ] of TiO 2 and Nb 2O5 is preferably 25%, more preferably 29%, 30% and 31%. The upper limit of the total content [ TiO 2+Nb2O5 ] is preferably 42%, more preferably 40%, 38%, 36%. By setting the total content [ TiO 2+Nb2O5 ] to the above range, a desired optical constant can be achieved.
In the glass of embodiment 3-1, the upper limit of the content of WO 3 is preferably 5%, more preferably in the order of 4%, 3% and 2%. The content of WO 3 may also be 0%. By setting the upper limit of the content of WO 3 to the above range, the transmittance can be improved, and the relative partial dispersions Pg, F and specific gravity can be reduced.
In embodiment 3-1, the upper limit of the content of Bi 2O3 is preferably 5%, and more preferably in the order of 4%, 3% and 2%. The lower limit of the content of Bi 2O3 is preferably 0%. By setting the content of Bi 2O3 to the above range, the thermal stability of the glass can be improved, and the relative partial dispersions Pg, F and specific gravity can be reduced.
In the glass of embodiment 3-1, the lower limit of the content of ZrO 2 is preferably 5%, more preferably in the order of 6%, 7% and 8%. The upper limit of the content of ZrO 2 is preferably 15%, more preferably in the order of 14%, 13%, 12%. By setting the content of ZrO 2 to the above range, a desired optical constant can be achieved, and the relative partial dispersions Pg, F can be reduced.
In the glass of embodiment 3-1, the upper limit of the content of Li 2 O is preferably 10%, more preferably in the order of 9%, 8% and 7%. The lower limit of the content of Li 2 O is preferably 2%, more preferably in the order of 3%, 4%, 5%. By setting the content of Li 2 O to the above range, a desired optical constant can be achieved, and chemical durability, weather resistance, and stability upon reheating can be maintained.
In the glass of embodiment 3-1, the upper limit of the Na 2 O content is preferably 18%, more preferably in the order of 15%, 14% and 13%. The lower limit of the Na 2 O content is preferably 8%, more preferably in the order of 9%, 10%, 11%.
In the glass of embodiment 3-1, the upper limit of the content of K 2 O is preferably 4.0%, more preferably in the order of 3.0%, 2.5% and 2.0%. The lower limit of the content of K 2 O is preferably 0%, more preferably in the order of 0.2%, 0.4% and 0.6%. The content of K 2 O may also be 0%.
Na 2 O and K 2 O are components for reducing relative partial dispersions Pg and F, and have the effects of reducing the liquid phase temperature and improving the thermal stability of glass, but when the content of these components is increased, chemical durability and weather resistance are reduced. Therefore, the respective contents of Na 2 O and K 2 O are preferably in the above ranges.
In the glass of embodiment 3-1, the upper limit of the content of Cs 2 O is preferably 5%, and more preferably in the order of 3%, 1%, 0.5%. The lower limit of the content of Cs 2 O is preferably 0%.
Cs 2 O has an effect of improving the thermal stability of the glass, but when the content thereof is increased, chemical durability and weather resistance are reduced. Therefore, each content of Cs 2 O is preferably in the above range.
In the glass of embodiment 3-1, the upper limit of the MgO content is preferably 10%, more preferably in the order of 5%, 3% and 1%. The lower limit of the MgO content is preferably 0%. The MgO content may be 0%.
In the glass of embodiment 3-1, the upper limit of the CaO content is preferably 10%, more preferably in the order of 5%, 3% and 1%. The lower limit of the CaO content is preferably 0%. The CaO content may be 0%.
In the glass of embodiment 3-1, the upper limit of the SrO content is preferably 10%, more preferably in the order of 5%, 3% and 1%. The lower limit of the SrO content is preferably 0%. The SrO content may be 0%.
In the optical glass according to embodiment 3-1, the upper limit of the content of BaO is preferably 10%, more preferably in the order of 5%, 3% and 1%. The lower limit of the content of BaO is preferably 0%. The BaO content may also be 0%. By setting the content of BaO to the above range, an increase in specific gravity can be suppressed.
MgO, caO, srO, baO are glass components having an effect of improving the thermal stability and devitrification resistance of the glass. However, when the content of these glass components increases, the specific gravity increases, high dispersibility is impaired, and the thermal stability and devitrification resistance of the glass decrease. Therefore, the respective contents of these glass components are preferably within the above ranges.
In the glass of embodiment 3-1, the upper limit of the total content R' O of MgO, caO, srO and BaO is preferably 10%, more preferably in the order of 4%, 2% and 1%. The lower limit of the total content R' O is preferably 0%. The total content R' O may also be 0%. By setting the total content R' O to the above range, an increase in specific gravity can be suppressed, and thermal stability can be maintained without impeding high dispersion.
In the glass of embodiment 3-1, the upper limit of the ZnO content is preferably 10%, more preferably in the order of 3%, 2.5% and 2%. The lower limit of the ZnO content is preferably 0%.
ZnO is a glass component having an effect of improving the thermal stability of glass. However, if the content of ZnO is too large, the specific gravity increases. Therefore, the content of ZnO is preferably in the above range from the viewpoint of improving the thermal stability of the glass and maintaining a desired optical constant.
In the optical glass according to embodiment 3-1, the upper limit of the content of La 2O3 is preferably 10%, more preferably in the order of 5%, 3% and 1%. The lower limit of the content of La 2O3 is preferably 0%, and the content of La 2O3 may be 0%. By setting the content of La 2O3 to the above range, a desired optical constant can be achieved, an increase in specific gravity can be suppressed, and relative partial dispersions Pg, F can be reduced.
In the glass of embodiment 3-1, the upper limit of the content of Y 2O3 is preferably 10%, more preferably in the order of 5%, 3% and 1%. The lower limit of the content of Y 2O3 is preferably 0%.
When the content of Y 2O3 is too large, the thermal stability of the glass decreases and the glass becomes easily devitrified during production. Therefore, the content of Y 2O3 is preferably in the above range from the viewpoint of suppressing the decrease in the thermal stability of the glass.
In the glass of embodiment 3-1, the upper limit of the content of Ta 2O5 is preferably 20%, more preferably in the order of 10%, 5%, 3%, 1%, 0.5%. The lower limit of the content of Ta 2O5 is preferably 0%.
Ta 2O5 is a glass component having an effect of improving the thermal stability of glass, and is a component that causes the relative partial dispersion Pg, F to decrease. On the other hand, when the content of Ta 2O5 is increased, the thermal stability of the glass is lowered, and melting residues of the glass raw material are likely to occur when the glass is melted. In addition, the specific gravity increases. Therefore, the content of Ta 2O5 is preferably in the above range.
In the glass of embodiment 3-1, the content of Sc 2O3 is preferably 2% or less. The lower limit of the content of Sc 2O3 is preferably 0%.
In the glass of embodiment 3-1, the content of HfO 2 is preferably 2% or less. The lower limit of the content of HfO 2 is preferably 0%, more preferably in the order of 0.05% and 0.1%.
Sc 2O3、HfO2 is an expensive component having an effect of improving the high dispersibility of glass. Therefore, each content of Sc 2O3、HfO2 is preferably within the above range.
In the glass of embodiment 3-1, the content of Lu 2O3 is preferably 2% or less. The lower limit of the content of Lu 2O3 is preferably 0%.
Lu 2O3 has an effect of improving high dispersibility of glass, but is also a glass component that causes an increase in specific gravity of glass because of a large molecular weight. Therefore, the content of Lu 2O3 is preferably in the above range.
In the glass of embodiment 3-1, the content of GeO 2 is preferably 2% or less. The lower limit of the content of GeO 2 is preferably 0%.
GeO 2 has an effect of improving high dispersibility of glass, but is an extremely expensive component among commonly used glass components. Therefore, the content of GeO 2 is preferably in the above range from the viewpoint of reducing the manufacturing cost of the glass.
In the glass of embodiment 3-1, the content of Gd 2O3 is preferably 2% or less. The lower limit of the content of Gd 2O3 is preferably 0%.
When the content of Gd 2O3 is too large, the heat stability of the glass is lowered. When the content of Gd 2O3 is too large, the specific gravity of the glass increases. Therefore, the content of Gd 2O3 is preferably in the above range from the viewpoint of keeping the thermal stability of the glass well and suppressing the increase of specific gravity.
In the glass of embodiment 3-1, the content of Yb 2O3 is preferably 2% or less. The lower limit of the Yb 2O3 content is preferably 0%.
Yb 2O3 has a larger molecular weight than La 2O3、Gd2O3、Y2O3, and thus increases the specific gravity of the glass. When the specific gravity of the glass increases, the mass of the optical element increases. For example, if a lens having a large mass is incorporated in an auto-focus type imaging lens, power required for driving the lens at the time of auto-focus increases, and battery consumption becomes severe. Therefore, it is preferable to reduce the content of Yb 2O3 to suppress an increase in specific gravity of the glass.
In addition, when the content of Yb 2O3 is too large, the thermal stability of the glass is lowered. The content of Yb 2O3 is preferably in the above range from the viewpoint of preventing a decrease in the thermal stability of the glass and suppressing an increase in specific gravity.
The glass of embodiment 3-1 is preferably composed mainly of the above-mentioned glass components, that is, SiO2、B2O3、P2O5、Al2O3、TiO2、Nb2O5、WO3、Bi2O3、ZrO2、Li2O、Na2O、K2O、Cs2O、MgO、CaO、SrO、BaO、ZnO、La2O3、Y2O3、Ta2O5、Sc2O3、HfO2、Lu2O3、GeO2、Gd2O3 and Yb 2O3, and the total content of the above-mentioned glass components is preferably more than 95%, more preferably more than 98%, still more preferably more than 99%, still more preferably more than 99.5%.
The glass of embodiment 3-1 is preferably composed of the above glass components, but may contain other components within a range that does not interfere with the operation and effect of embodiment 3. In addition, in the invention of claim 3, the inclusion of unavoidable impurities is not excluded.
(Other Components)
In addition to the above components, the optical glass may contain Sb 2O3、CeO2 or the like in a small amount as a refining agent. The total amount of the clarifying agent (external proportion addition amount) is preferably set to 0% or more and less than 1%, more preferably set to 0% or more and 0.5% or less.
The external ratio added amount is a value expressed as weight percentage of the added amount of the fining agent when the total content of all glass components except the fining agent is set to 100%.
Pb, cd, as, th and the like are components that may cause environmental burden. Accordingly, the content of PbO, cdO, thO 2 is preferably 0 to 0.1%, more preferably 0 to 0.05%, still more preferably 0 to 0.01%, and particularly preferably substantially no PbO, cdO, thO 2.
The content of As 2O3 is preferably 0 to 0.1%, more preferably 0 to 0.05%, still more preferably 0 to 0.01%, and particularly preferably substantially no As 2O3.
In addition, the optical glass can obtain high transmittance in a wide range of the visible region. In order to effectively use such features, it is preferable that the coloring element is not contained. As elements of colorability, cu, co, ni, fe, cr, eu, nd, er, V and the like can be exemplified. The content of any element is preferably less than 100 mass ppm, more preferably 0 to 80 mass ppm, still more preferably 0 to 50 mass ppm, and particularly preferably substantially no element.
Ga, te, tb, and the like are components that do not require introduction, and are also expensive components. Accordingly, the content of Ga 2O3、TeO2、TbO2 in mass% is preferably 0 to 0.1%, more preferably 0 to 0.05%, still more preferably 0 to 0.01%, still more preferably 0 to 0.005%, still more preferably 0 to 0.001%, and particularly preferably substantially no content.
(Glass characteristics)
< Refractive index nd >)
In the optical glass of embodiment 3-1, the refractive index nd is preferably 1.69 to 1.76. The refractive index nd may be 1.695 to 1.755 or 1.70 to 1.75. The component that relatively increases the refractive index nd is Nb 2O5、TiO2、ZrO2、Ta2O5、La2O3. The component that relatively lowers the refractive index nd is SiO 2、B2O3、Li2O、Na2O、K2 O. By properly adjusting the content of these components, the refractive index nd can be controlled.
< Abbe number vd >)
In the optical glass of embodiment 3-1, the Abbe number vd is preferably 30 to 36. The Abbe number vd may be 30.5 to 35.8 or 31 to 35.5. The component that relatively decreases the abbe number vd is Nb 2O5、TiO2、ZrO2、Ta2O5. The component SiO2、B2O3、Li2O、Na2O、K2O、La2O3、BaO、CaO、SrO. which relatively increases the Abbe number vd is a component which can control the Abbe number vd by properly adjusting the content of the component.
< Specific gravity of glass >
The specific gravity of the optical glass according to embodiment 3-1 is preferably 3.19 or less, more preferably 3.18 or less, still more preferably 3.17 or less, and still more preferably 3.16 or less. The lower limit is not particularly limited as the specific gravity is smaller, but is generally about 3.05. The components that relatively increase the specific gravity are BaO, la 2O3、ZrO2、Nb2O5、Ta2O5, and the like. The component that relatively reduces the specific gravity is SiO 2、B2O3、Li2O、Na2O、K2 O or the like. The specific gravity can be controlled by adjusting the content of these components.
< Relative partial Dispersion Pg, F >)
The upper limit of the relative partial dispersion Pg, F of the optical glass of embodiment 3-1 is preferably 0.5950, and more preferably in the order of 0.5945, 0.5940, 0.5935. The lower limit of the relative partial dispersion Pg, F is preferably 0.5780, and more preferably 0.5785, 0.5790, 0.5795, 0.5805, 0.5815, 0.5830 are further preferable. By setting the relative partial dispersion Pg, F to the above range, an optical glass suitable for high-order chromatic aberration correction can be obtained.
The upper limit of the deviation Δpg of the relative partial dispersion Pg, F of the optical glass according to embodiment 3-1 is preferably 0.0015, and more preferably in the order of 0.0012, 0.0010, and 0.0008. The lower limit of the deviation Δpg, F is preferably-0.0060, more preferably in the order of-0.0048, -0.0045, -0.0042, -0.0040, -0.0035, -0.0025
< Liquid phase temperature >)
The liquid phase temperature LT of the optical glass of embodiment 3-1 is preferably 1200℃or lower, more preferably 1190℃or lower, 1180℃or lower, and still more preferably 1170℃or lower. By setting the liquid phase temperature to the above range, the melting and forming temperatures of the glass can be reduced, and as a result, erosion of glass melting devices (e.g., a crucible, a stirrer for melting glass, etc.) in the melting step can be reduced. The lower limit of the liquid phase temperature LT is not particularly limited, but is generally about 1000 ℃. The liquidus temperature LT is determined based on the balance of the contents of all glass components. Among them, the content of SiO 2、B2O3、Li2O、Na2O、K2 O and the like has a large influence on the liquid phase temperature LT.
The liquid phase temperature was determined as follows. 10cc (10 ml) of glass was charged into a platinum crucible, melted at 1250 to 1400 ℃ for 15 to 30 minutes, cooled to a temperature below the glass transition temperature Tg, and the glass was charged into a melting furnace at a given temperature together with the platinum crucible and kept for 2 hours. The temperature was kept at 1000℃or higher, and at 5℃or 10℃intervals, the glass was cooled after 2 hours, and the presence or absence of crystals in the glass was observed with a 100-fold optical microscope. The minimum temperature at which no crystals precipitate was set to the liquid phase temperature.
< Glass transition temperature Tg >)
The upper limit of the glass transition temperature Tg of the optical glass according to embodiment 3-1 is preferably 580℃and more preferably in the order of 575℃and 570℃and 565 ℃. The lower limit of the glass transition temperature Tg is preferably 510℃and more preferably 515℃and 520℃and 525 ℃. The component that relatively lowers the glass transition temperature Tg is Li 2O、Na2O、K2 O or the like. The component that relatively increases the glass transition temperature Tg is La 2O3、ZrO2、Nb2O5 or the like. By properly adjusting the content of these components, the glass transition temperature Tg can be controlled.
< Stability upon reheat >
In the optical glass according to embodiment 3-1, the number of crystals observed per 1g is preferably 20 or less, more preferably 10 or less, when heated at the glass transition temperature Tg for 10 minutes and further heated at a temperature of 140 to 250℃higher than the Tg for 10 minutes.
The stability at the time of reheating was measured as follows. A glass sample having a size of 1cm by 0.8cm was heated in a 1 st test furnace set to a glass transition temperature Tg of the glass sample for 10 minutes, and further heated in a2 nd test furnace set to a temperature 140 to 250℃higher than the glass transition temperature Tg for 10 minutes, and then the presence or absence of crystallization was confirmed by an optical microscope (observation magnification: 10 to 100 times). Then, the corresponding number of crystals per 1g was measured. In addition, the presence or absence of cloudiness of the glass was visually confirmed.
The optical glass according to embodiment 3-1 can be produced in the same manner as in embodiment 1. The optical element and the like may be manufactured in the same manner as in embodiment 1.
Embodiment 3-2
With respect to the optical glass of embodiment 3-2,
The mass ratio of the content of SiO 2 to the content of Nb 2O5 [ SiO 2/Nb2O5 ] is more than 1.05,
The mass ratio [ ZrO 2/Nb2O5 ] of the content of ZrO 2 relative to the content of Nb 2O5 is more than 0.25,
The mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is greater than 0.65,
The total content of TiO 2 and BaO [ TiO 2 +BaO ] is less than 10 mass%,
The mass ratio of the content of Ta 2O5 to the total content of TiO 2 and Nb 2O5 [ Ta 2O5/(TiO2+Nb2O5) ] is less than 0.3,
The optical glass satisfies 1 or more of the following (c) and (d):
(c) The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 1.1 mass%,
(D) The mass ratio of the total content R 2 O to the total content of the total content R 2 O and the total content R ' O [ R 2O/(R2 O+R ' O) ] is greater than 0.05, the total content R 2 O being the total content of Li 2O、Na2 O and K 2 O, the total content R ' O being the total content of MgO, caO, srO and BaO.
In the optical glass of embodiment 3-2, the mass ratio [ SiO 2/Nb2O5 ] of the content of SiO 2 to the content of Nb 2O5 is more than 1.05. The lower limit of the mass ratio [ SiO 2/Nb2O5 ] is preferably 1.09, more preferably in the order of 1.11, 1.15, 1.17. The upper limit of the mass ratio [ SiO 2/Nb2O5 ] is preferably 2.10, more preferably in the order of 2.05, 2.00, and 1.95. By setting the mass ratio [ SiO 2/Nb2O5 ] to the above range, the specific gravity of the glass can be reduced while maintaining desired optical constants (refractive index nd, abbe number vd).
In the optical glass of embodiment 3-2, the mass ratio [ ZrO 2/Nb2O5 ] of the content of ZrO 2 relative to the content of Nb 2O5 is more than 0.25. The lower limit of the mass ratio [ ZrO 2/Nb2O5 ] is preferably 0.26, and more preferably in the order of 0.27, 0.28, 0.29, 0.30, 0.305, 0.310, 0.315. The upper limit of the mass ratio [ ZrO 2/Nb2O5 ] is preferably 0.65, and more preferably in the order of 0.61, 0.57, and 0.53. By setting the lower limit of the mass ratio [ ZrO 2/Nb2O5 ] to the above range, the relative partial dispersions Pg, F can be reduced, the raw material cost can be reduced, and the desired optical constant and solubility can be maintained.
In the optical glass of embodiment 3-2, the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is more than 0.65. The lower limit of the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] is preferably 0.66, more preferably in the order of 0.67, 0.70, 0.73, 0.76, 0.80, 0.83, 0.86, 0.88. The upper limit of the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] is preferably 1.20, more preferably in the order of 1.14, 1.12, and 1.10. By setting the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] to the above range, the thermal stability of the glass can be maintained, and a desired optical constant can be obtained.
In the optical glass of embodiment 3-2, the total content of TiO 2 and BaO [ TiO 2 +BaO ] is less than 10%. The upper limit of the total content [ TiO 2 +BaO ] is preferably 8.0%, more preferably in the order of 7.8%, 7.6%, 7.4%. The lower limit of the total content [ Ti 2 +BaO ] is preferably 0%, more preferably in the order of 1%, 2% and 3%. By setting the upper limit of the total content [ Ti 2 +BaO ] to the above range, the relative partial dispersions Pg, F can be reduced, and the specific gravity of the glass can be reduced.
In the optical glass of embodiment 3-2, the mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] of the content of Ta 2O5 to the total content of TiO 2 and Nb 2O5 is less than 0.3. The upper limit of the mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] is preferably 0.25, more preferably in the order of 0.20, 0.15. The lower limit of the mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] is preferably 0, and more preferably in the order of 0.05, 0.07, and 0.10. The mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] may also be 0. By setting the upper limit of the mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] to the above range, the specific gravity of glass can be reduced, and the raw material cost can be reduced.
The optical glass according to embodiment 3-2 satisfies 1 or more of the following (c) and (d):
(c) The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 1.1 percent,
(D) The mass ratio of the total content R 2 O to the total content of the total content R 2 O and the total content R ' O [ R 2O/(R2 O+R ' O) ] is greater than 0.05, the total content R 2 O being the total content of Li 2O、Na2 O and K 2 O, the total content R ' O being the total content of MgO, caO, srO and BaO.
That is, in the optical glass according to embodiment 3-2, the total content R 2 O of Li 2O、Na2 O and K 2 O may be set to be more than 1.1%. The total content R 2 O is preferably more than 9%, and the lower limit thereof is more preferably in the order of 15.0%, 15.5%, 16.0%, 16.5%. The upper limit of the total content R 2 O is preferably 22.0%, more preferably in the order of 21.7%, 21.4%, 21.1%. By setting the total content R 2 O to the above range, the specific gravity of the glass can be reduced, and the stability of the glass at reheating can be maintained.
In the optical glass according to embodiment 3-2, the mass ratio of the total content R 2 O [ R 2O/(R2 o+r 'O) ] to the total content R 2 O and MgO, caO, srO of Li 2O、Na2 O and K 2 O and the total content R' O of BaO may be set to be more than 0.05. The mass ratio [ R 2O/(R2 O+R' O) ] is preferably more than 0.6, and the lower limit thereof is more preferably in the order of 0.80, 0.82, 0.84, 0.86. The upper limit of the mass ratio [ R 2O/(R2 O+R' O) ] is preferably 1.00, and more preferably in the order of 0.99, 0.98, and 0.95. By setting the mass ratio [ R 2O/(R2 O+R' O) ] to the above range, the specific gravity of the glass can be reduced, and the stability of the glass at the time of reheating can be maintained.
In the optical glass of embodiment 3-2, the mass ratio [ ZnO/Nb 2O5 ] of the content of ZnO to the content of Nb 2O5 is preferably less than 0.14, and the upper limit thereof is more preferably in the order of 0.125, 0.115, and 0.105. The lower limit of the mass ratio [ ZnO/Nb 2O5 ] is preferably 0, and more preferably 0.02, 0.05, and 0.07. The mass ratio [ ZnO/Nb 2O5 ] may be 0. By setting the upper limit of the mass ratio [ ZnO/Nb 2O5 ] to the above range, the specific gravity of the glass can be reduced, and a desired optical constant can be obtained.
The optical glass according to embodiment 3-2 may have the same content and ratio of glass components as those in embodiment 3-1. The glass characteristics, the production of optical glass, the production of optical elements, and the like in embodiment 3-2 may be the same as those in embodiment 3-1.
Embodiment 3 to 3
For the optical glass of embodiments 3-3,
The mass ratio of the content of SiO 2 to the content of Nb 2O5 [ SiO 2/Nb2O5 ] is more than 1.05,
The mass ratio [ ZrO 2/Nb2O5 ] of the content of ZrO 2 relative to the content of Nb 2O5 is more than 0.25,
The mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is greater than 0.65,
The total content of TiO 2 and BaO [ TiO 2 +BaO ] is less than 10 mass%,
The mass ratio of the content of ZnO to the content of Nb 2O5 [ ZnO/Nb 2O5 ] is less than 0.14,
The optical glass satisfies 1 or more of the following (e) and (f):
(e) The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 1.1 mass%,
(F) The mass ratio of the total content R 2 O to the total content of the total content R 2 O and the total content R ' O [ R 2O/(R2 O+R ' O) ] is greater than 0.05, the total content R 2 O being the total content of Li 2O、Na2 O and K 2 O, the total content R ' O being the total content of MgO, caO, srO and BaO.
In the optical glass of embodiment 3 to 3, the mass ratio [ SiO 2/Nb2O5 ] of the content of SiO 2 to the content of Nb 2O5 is more than 1.05. The lower limit of the mass ratio [ SiO 2/Nb2O5 ] is preferably 1.09, more preferably in the order of 1.11, 1.15, 1.17. The upper limit of the mass ratio [ SiO 2/Nb2O5 ] is preferably 2.10, more preferably in the order of 2.05, 2.00, and 1.95. By setting the mass ratio [ SiO 2/Nb2O5 ] to the above range, the specific gravity of the glass can be reduced while maintaining desired optical constants (refractive index nd, abbe number vd).
In the optical glass of embodiment 3 to 3, the mass ratio [ ZrO 2/Nb2O5 ] of the content of ZrO 2 with respect to the content of Nb 2O5 is more than 0.25. The lower limit of the mass ratio [ ZrO 2/Nb2O5 ] is preferably 0.26, and more preferably in the order of 0.27, 0.28, 0.29, 0.30, 0.305, 0.310, 0.315. The upper limit of the mass ratio [ ZrO 2/Nb2O5 ] is preferably 0.65, and more preferably in the order of 0.61, 0.57, and 0.53. By setting the lower limit of the mass ratio [ ZrO 2/Nb2O5 ] to the above range, the relative partial dispersions Pg, F can be reduced, the raw material cost can be reduced, and the desired optical constant and solubility can be maintained.
In the optical glass of embodiment 3 to 3, the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is more than 0.65. The lower limit of the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] is preferably 0.66, more preferably in the order of 0.67, 0.70, 0.73, 0.76, 0.80, 0.83, 0.86, 0.88. The upper limit of the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] is preferably 1.20, more preferably in the order of 1.14, 1.12, and 1.10. By setting the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] to the above range, the thermal stability of the glass can be maintained, and a desired optical constant can be obtained.
In the optical glass of embodiments 3 to 3, the total content of TiO 2 and BaO [ TiO 2 +BaO ] is less than 10%. The upper limit of the total content [ TiO 2 +BaO ] is preferably 8.0%, more preferably in the order of 7.8%, 7.6%, 7.4%. The lower limit of the total content [ Ti 2 +BaO ] is preferably 0%, more preferably in the order of 1%, 2% and 3%. By setting the upper limit of the total content [ Ti 2 +BaO ] to the above range, the relative partial dispersions Pg, F can be reduced, and the specific gravity of the glass can be reduced.
In the optical glass of embodiment 3 to 3, the mass ratio [ ZnO/Nb 2O5 ] of the content of ZnO to the content of Nb 2O5 is less than 0.14. The upper limit of Nb 2O5 is preferably 0.125, more preferably in the order of 0.115 and 0.105. The lower limit of the mass ratio [ ZnO/Nb 2O5 ] is preferably 0, and more preferably 0.02, 0.05, and 0.07. The mass ratio [ ZnO/Nb 2O5 ] may be 0. By setting the upper limit of the mass ratio [ ZnO/Nb 2O5 ] to the above range, the specific gravity of the glass can be reduced, and a desired optical constant can be obtained.
The optical glass according to embodiment 3 to 3 satisfies 1 or more of the following (e) and (f):
(e) The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 1.1 percent,
(F) The mass ratio of the total content R 2 O to the total content of the total content R 2 O and the total content R ' O [ R 2O/(R2 O+R ' O) ] is greater than 0.05, the total content R 2 O being the total content of Li 2O、Na2 O and K 2 O, the total content R ' O being the total content of MgO, caO, srO and BaO.
That is, in the optical glass according to embodiment 3 to 3, the total content R 2 O of Li 2O、Na2 O and K 2 O may be set to be more than 1.1%. The total content R 2 O is preferably more than 9%, and the lower limit thereof is more preferably in the order of 15.0%, 15.5%, 16.0%, 16.5%. The upper limit of the total content R 2 O is preferably 22.0%, more preferably in the order of 21.7%, 21.4%, 21.1%. By setting the total content R 2 O to the above range, the specific gravity of the glass can be reduced, and the stability of the glass at reheating can be maintained.
In addition, in the optical glass of embodiment 3 to 3, the mass ratio [ R 2O/(R2 O+R 'O) ] of the total content R 2 O can be made larger than 0.05 with respect to the total contents R 2 O and MgO, caO, srO of the total contents of Li 2O、Na2 O and K 2 O and the total content R' O of BaO. The mass ratio [ R 2O/(R2 O+R' O) ] is preferably more than 0.6, and the lower limit thereof is more preferably in the order of 0.80, 0.82, 0.84, 0.86. The upper limit of the mass ratio [ R 2O/(R2 O+R' O) ] is preferably 0.95, more preferably in the order of 0.98, 0.99, and 1.00. By setting the mass ratio [ R 2O/(R2 O+R' O) ] to the above range, the specific gravity of the glass can be reduced, and the stability of the glass at the time of reheating can be maintained.
In the optical glass of embodiments 3 to 3, the mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] of the content of Ta 2O5 to the total content of TiO 2 and Nb 2O5 is preferably less than 0.3, and the upper limit thereof is more preferably in the order of 0.25, 0.20, 0.15. The lower limit of the mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] is preferably 0, and more preferably in the order of 0.05, 0.07, and 0.10. The mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] may also be 0. By setting the upper limit of the mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] to the above range, the specific gravity of glass can be reduced, and the raw material cost can be reduced.
The optical glass according to embodiment 3 to 3 may have the same content and ratio of glass components as those in embodiment 3 to 1. The glass characteristics and the manufacturing of optical glass, optical element, and the like in embodiment 3-3 may be the same as those in embodiment 3-1.
Embodiment 3 to 4
The optical glass of embodiment 3 to 4 has an Abbe number vd of 30 to 36,
The specific gravity is not more than 3.19,
The relative partial dispersion Pg, F has a deviation ΔPg, F of 0.0015 or less.
In the optical glass according to embodiment 3 to 4, the Abbe number vd is 30 to 36. The Abbe number vd may be 30.5 to 35.8 or 31 to 35.5. The component that relatively decreases the abbe number vd is Nb 2O5、TiO2、ZrO2、Ta2O5. The component SiO2、B2O3、Li2O、Na2O、K2O、La2O3、BaO、CaO、SrO. which relatively increases the Abbe number vd is a component which can control the Abbe number vd by properly adjusting the content of the component.
In the optical glass of embodiments 3 to 4, the specific gravity is 3.19 or less. The specific gravity is preferably 3.18 or less, more preferably 3.17 or less, and still more preferably 3.16 or less. The lower limit is not particularly limited as the specific gravity is smaller, but is generally about 3.05.
In the optical glass of embodiments 3 to 4, the deviation Δpg of the relative partial dispersion Pg, F is 0.0015 or less. The upper limit of the deviation Δpg, F is preferably 0.0012, more preferably in the order of 0.0010 and 0.0008. The lower limit of the deviation Δpg, F is preferably-0.0060, more preferably-0.0048, -0.0045, -0.0042, -0.0040, -0.0035, and-0.0025.
In general, the relative partial dispersion Pg, F tends to decrease with an increase in the abbe number vd. Therefore, for embodiments 3 to 4, the relative partial dispersion Pg, F is defined using Δpg, F described above, not the relative partial dispersion Pg, F itself. The abbe number vd is set to 0.0015 or less, whereby an optical glass suitable for high-order chromatic aberration correction can be improved. Further, by setting the specific gravity to 3.19 or less, the optical element can be made lightweight.
Next, preferred embodiments of the content and ratio of the glass components in the optical glass according to embodiments 3 to 4 will be described in detail below.
In the optical glass of embodiments 3 to 4, the mass ratio [ SiO 2/Nb2O5 ] of the content of SiO 2 to the content of Nb 2O5 is preferably more than 1.05, and the lower limit thereof is more preferably in the order of 1.09, 1.11, 1.15, 1.17. The upper limit of the mass ratio [ SiO 2/Nb2O5 ] is preferably 1.50, more preferably in the order of 1.48, 1.46 and 1.44. By setting the mass ratio [ SiO 2/Nb2O5 ] to the above range, the specific gravity of the glass can be reduced while maintaining desired optical constants (refractive index nd, abbe number vd).
In the optical glass of embodiments 3 to 4, the mass ratio [ ZrO 2/Nb2O5 ] of the content of ZrO 2 relative to the content of Nb 2O5 is preferably more than 0.25, and the lower limit thereof is more preferably in the order of 0.26, 0.27, 0.28, 0.29, 0.30, 0.305, 0.310, 0.315. The upper limit of the mass ratio [ ZrO 2/Nb2O5 ] is preferably 0.50, more preferably in the order of 0.47, 0.44 and 0.41. By setting the lower limit of the mass ratio [ ZrO 2/Nb2O5 ] to the above range, the relative partial dispersions Pg, F can be reduced, the raw material cost can be reduced, and the desired optical constant and solubility can be maintained.
In the optical glass of embodiments 3 to 4, the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is preferably more than 0.65, and the lower limit thereof is more preferably in the order of 0.66, 0.67, 0.69, 0.71, 0.73, 0.76, 0.80, 0.83, 0.86, 0.88. The upper limit of the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] is preferably 1.20, more preferably in the order of 1.14, 1.12, and 1.10. By setting the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] to the above range, the thermal stability of the glass can be maintained, and a desired optical constant can be obtained.
In the optical glass of embodiments 3 to 4, the total content of TiO 2 and BaO [ TiO 2 +BaO ] is preferably less than 10%, and the upper limit thereof is more preferably in the order of 8.0%, 7.8%, 7.6% and 7.4%. The lower limit of the total content [ Ti 2 +BaO ] is preferably 0%, more preferably in the order of 1%, 2% and 3%. By setting the upper limit of the total content [ Ti 2 +BaO ] to the above range, the relative partial dispersions Pg, F can be reduced, and the specific gravity of the glass can be reduced.
In the optical glass of embodiments 3 to 4, the mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] of the content of Ta 2O5 to the total content of TiO 2 and Nb 2O5 is preferably less than 0.3, and the upper limit thereof is more preferably in the order of 0.25, 0.20, 0.15. The lower limit of the mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] is preferably 0, and more preferably in the order of 0.05, 0.07, and 0.10. The mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] may also be 0. By setting the upper limit of the mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] to the above range, the specific gravity of glass can be reduced, and the raw material cost can be reduced.
In the optical glass of embodiments 3 to 4, the mass ratio [ ZnO/Nb 2O5 ] of the content of ZnO to the content of Nb 2O5 is preferably less than 0.14, and the upper limit thereof is more preferably in the order of 0.125, 0.115, and 0.105. The lower limit of the mass ratio [ ZnO/Nb 2O5 ] is preferably 0, and more preferably 0.02, 0.05, and 0.07. The mass ratio [ ZnO/Nb 2O5 ] may be 0. By setting the upper limit of the mass ratio [ ZnO/Nb 2O5 ] to the above range, the specific gravity of the glass can be reduced, and a desired optical constant can be obtained.
The optical glass according to embodiments 3 to 4 preferably satisfies 1 or more of the following (g) and (h):
(g) The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 1.1 percent,
(H) The mass ratio of the total content R 2 O to the total content of the total content R 2 O and the total content R ' O [ R 2O/(R2 O+R ' O) ] is greater than 0.05, the total content R 2 O being the total content of Li 2O、Na2 O and K 2 O, the total content R ' O being the total content of MgO, caO, srO and BaO.
That is, in the optical glass according to embodiments 3 to 4, the total content R 2 O of Li 2O、Na2 O and K 2 O may be set to be more than 1.1%. The total content R 2 O is preferably more than 9%, and the lower limit thereof is more preferably in the order of 15.0%, 15.5%, 16.0%, 16.5%. The upper limit of the total content R 2 O is preferably 22.0%, more preferably in the order of 21.7%, 21.4%, 21.1%. By setting the total content R 2 O to the above range, the specific gravity of the glass can be reduced, and the stability of the glass at reheating can be maintained.
In addition, in the optical glass according to embodiments 3 to 4, the mass ratio [ R 2O/(R2 O+R ' O) ] of the total content R 2 O may be set to be larger than 0.05 with respect to the total contents R 2 O and MgO, caO, srO of the total contents R ' O of Li 2O、Na2 O and K 2 O and the total content R ' O of BaO. The mass ratio [ R 2O/(R2 O+R' O) ] is preferably more than 0.6, and the lower limit thereof is more preferably in the order of 0.80, 0.82, 0.84, 0.86. The upper limit of the mass ratio [ R 2O/(R2 O+R' O) ] is preferably 0.95, more preferably in the order of 0.98, 0.99, and 1.00. By setting the mass ratio [ R 2O/(R2 O+R' O) ] to the above range, the specific gravity of the glass can be reduced, and the stability of the glass at the time of reheating can be maintained.
The optical glass according to embodiment 3 to 4 may have the same content and ratio of glass components as those of embodiment 3 to 1. The glass characteristics other than those described above in embodiment 3-4 and the manufacturing of optical glass, optical element, and the like may be the same as those in embodiment 3-1.
In embodiment 3-4, any of the embodiments 3-1 to 3-3 may be used.
Invention 4
[ Background of the invention 4 ]
In order to reduce power consumption when the autofocus function is driven, the optical element mounted in the autofocus optical system is required to be lightweight. If the specific gravity of the glass can be reduced, the weight of the optical element such as a lens can be reduced. In addition, for correction of chromatic aberration, the relative partial dispersion Pg, F is required to be small.
Further, as a method for producing such an optical glass used in an optical system, a reheat press method for reheating and shaping glass is exemplified. In this method, silicate-based optical glass having a high refractive index and high dispersibility is likely to undergo devitrification when reheated. Therefore, high stability is required that the glass interior is not easily devitrified when the glass is reheated.
Patent document 4-1 discloses an optical glass having a refractive index nd of 1.674 or more and an abbe number vd of 30.2 or more. However, the optical glass described in patent document 4-1 has low homogeneity, and devitrification is observed during reheating. In addition, the conditions of low specific gravity and low Pg, F are not satisfied. Accordingly, an optical glass having a desired optical constant and having higher performance is desired.
[ Prior Art document of the 4 th invention ]
Patent literature
Patent document 4-1: japanese patent laid-open No. 2017-105702
[ 4 Th summary of the invention ]
[ Problem to be solved by the invention of 4 ]
An object of the invention of claim 4 is to provide an optical glass having a desired optical constant, a specific gravity as small as possible, a small relative partial dispersion Pg and F, and excellent stability at the time of reheating and high homogeneity, and an optical element formed of the optical glass.
[ Means of solving the problems ]
The gist of the invention of claim 4 is as follows.
(1) An optical glass, wherein,
The mass ratio of the content of SiO 2 to the total content of Nb 2O5 and TiO 2 [ SiO 2/(Nb2O5+TiO2) ] is greater than 0.80,
The mass ratio of the content of SiO 2 to the content of Na 2 O [ SiO 2/Na2 O ] is 2.5-8.5,
The mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] of the total content of SiO 2、B2O3 and P 2O5 to the total content of Li 2O、Na2 O and K 2 O is 1.45-4.55,
The mass ratio of Na 2 O content to the total content of Li 2O、Na2 O and K 2 O [ Na 2O/(Li2O+Na2O+K2 O) ] is 0.45 or more,
The total content of SiO 2 and Nb 2O5 [ SiO 2+Nb2O5 ] is 62 to 84 mass%.
(2) An optical glass, wherein,
The mass ratio of the content of SiO 2 to the total content of Nb 2O5 and TiO 2 [ SiO 2/(Nb2O5+TiO2) ] is greater than 0.80,
The mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is greater than 0.7,
The mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] of the total content of SiO 2、B2O3 and P 2O5 to the total content of Li 2O、Na2 O and K 2 O is 1.45-4.55,
The mass ratio of Na 2 O content to the total content of Li 2O、Na2 O and K 2 O [ Na 2O/(Li2O+Na2O+K2 O) ] is 0.45 or more,
The total content of SiO 2 and Nb 2O5 [ SiO 2+Nb2O5 ] is 62 to 84 mass%.
(3) An optical glass having an Abbe number vd of 30 to 36,
The specific gravity is not more than 3.4,
The relative partial dispersion Pg, F has a deviation ΔPg, F of 0.0030 or less.
(4) An optical element formed of the optical glass according to any one of the above (1) to (3).
[ Effect of the invention of the 4 th ]
According to the invention of claim 4, an optical glass having a desired optical constant, a specific gravity as small as possible, a small relative partial dispersion Pg, F, and excellent stability at the time of reheating and having high homogeneity, and an optical element formed of the optical glass can be provided.
[ 4 Th invention ] detailed description of the preferred embodiments
The abbe number vd is used as a value indicating a property related to dispersion, and is expressed by the following formula. Here, nF is the refractive index of blue hydrogen at F-ray (wavelength 486.13 nm), nC is the refractive index of red hydrogen at C-ray (656.27 nm).
νd＝(nd-1)/(nF-nC)
The optical glass according to embodiment 4 will be described below as embodiment 4-1, embodiment 4-2 and embodiment 4-3. The actions and effects of the respective glass components in embodiments 4-2 and 4-3 are the same as those of the respective glass components in embodiment 4-1. Therefore, in embodiments 4-2 and 4-3, the repeated descriptions of embodiment 4-1 are omitted as appropriate.
In embodiments 4-1, 4-2 and 4-3, the relative partial dispersions Pg and F are represented by refractive indices ng, nF and nC in g-rays, F-rays and C-rays as follows.
Pg,F＝(ng-nF)/(nF-nC)
In a plane where the horizontal axis is the abbe number vd and the vertical axis is the relative partial dispersion Pg, F, the normal line is expressed by the following formula.
Pg,F(0)＝0.6483-(0.0018×νd)
The deviation Δpg, F of the relative partial dispersion Pg, F with respect to the normal line is expressed as follows.
ΔPg,F＝Pg,F-Pg,F(0)
Embodiment 4-1
The optical glass according to embodiment 4-1 is characterized in that,
The mass ratio of the content of SiO 2 to the total content of Nb 2O5 and TiO 2 [ SiO 2/(Nb2O5+TiO2) ] is greater than 0.80,
The mass ratio of the content of SiO 2 to the content of Na 2 O [ SiO 2/Na2 O ] is 2.5-8.5,
The mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] of the total content of SiO 2、B2O3 and P 2O5 to the total content of Li 2O、Na2 O and K 2 O is 1.45-4.55,
The mass ratio of Na 2 O content to the total content of Li 2O、Na2 O and K 2 O [ Na 2O/(Li2O+Na2O+K2 O) ] is 0.45 or more,
The total content of SiO 2 and Nb 2O5 [ SiO 2+Nb2O5 ] is 62-84%.
In the optical glass of embodiment 4-1, the mass ratio [ SiO 2/(Nb2O5+TiO2 ] of the content of SiO 2 to the total content of Nb 2O5 and TiO 2 is more than 0.80. The lower limit of the mass ratio [ SiO 2/(Nb2O5+TiO2) ] is preferably 0.83, more preferably in the order of 0.85, 0.86, 0.87, 0.88. The upper limit of the mass ratio [ SiO 2/(Nb2O5+TiO2) ] is preferably 1.50, more preferably in the order of 1.40, 1.30, 1.20. By setting the mass ratio [ SiO 2/(Nb2O5+TiO2) ] to the above range, crystallization of the glass can be suppressed, and an optical glass excellent in homogeneity and stability upon reheating can be obtained.
In the optical glass of embodiment 4-1, the mass ratio [ SiO 2/Na2 O ] of the content of SiO 2 to the content of Na 2 O is 2.5 to 8.5. The lower limit of the mass ratio [ SiO 2/Na2 O ] is preferably 2.6, more preferably in the order of 2.65, 2.70, 2.75. The upper limit of the mass ratio [ SiO 2/Na2 O ] is more preferably 8.2, and further more preferably in the order of 8.0, 7.8, and 7.6. By setting the mass ratio [ SiO 2/Na2 O ] to the above range, an optical glass excellent in homogeneity and stability upon reheating can be obtained.
In the optical glass of embodiment 4-1, the mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] of the total content of SiO 2、B2O3 and P 2O5 to the total content of Li 2O、Na2 O and K 2 O is 1.45 to 4.55. The lower limit of the mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] is preferably 1.70, more preferably in the order of 1.72, 1.74, 1.76. The upper limit of the mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] is preferably 4.20, more preferably in the order of 4.0, 3.95, and 3.90. By setting the mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] to the above range, crystallization of the glass can be suppressed.
In the optical glass of embodiment 4-1, the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] of the Na 2 O content to the total content of Li 2O、Na2 O and K 2 O is 0.45 or more. The lower limit of the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] is preferably 0.46, more preferably in the order of 0.47, 0.48, 0.49. The upper limit of the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] is preferably 0.97, and more preferably in the order of 0.96, 0.90, 0.85, 0.80, 0.75, 0.70. By setting the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] within the above range, the liquid phase temperature can be reduced, and the thermal stability of the glass can be improved. In addition, crystallization of the glass can be suppressed, and an optical glass excellent in homogeneity and stability upon reheating can be obtained.
In the optical glass of embodiment 4-1, the total content [ SiO 2+Nb2O5 ] of SiO 2 and Nb 2O5 is 62 to 84%. The lower limit of the total content [ SiO 2+Nb2O5 ] is preferably 63.0%, more preferably in the order of 63.5%, 64.0%, 64.5%. The upper limit of the total content [ SiO 2+Nb2O5 ] is preferably 83%, and more preferably 82.7%, 82.3%, and 82.1% are in this order. By setting the total content [ SiO 2+Nb2O5 ] to the above range, the liquid phase temperature can be reduced, and the thermal stability of the glass can be improved. Furthermore, crystallization of the glass can be suppressed.
In the optical glass of embodiment 4-1, the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is preferably more than 0.7. The lower limit of the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] is more preferably 0.73, and further more preferably in the order of 0.75, 0.77, 0.79. The upper limit of the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] is preferably 1.15, more preferably in the order of 1.13, 1.11, and 1.09. By setting the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] within the above range, the liquid phase temperature can be reduced, and the thermal stability of the glass can be improved.
The content and ratio of the glass components other than those described above in the optical glass according to embodiment 4-1 will be described in detail below.
In the optical glass of embodiment 4-1, the lower limit of the content of SiO 2 is preferably 33.0%, more preferably in the order of 33.5%, 34.0% and 34.5%. The upper limit of the content of SiO 2 is preferably 44.0%, more preferably in the order of 43.5%, 43.0%, 42.5%. By setting the content of SiO 2 to the above range, the specific gravity of the glass can be reduced, and further, the stability at reheating of the glass and a desired optical constant can be obtained.
In the optical glass of embodiment 4-1, the upper limit of the content of B 2O3 is preferably 5.0%, more preferably in the order of 4.5%, 4.0% and 3.5%. The lower limit of the content of B 2O3 is preferably 0%, more preferably in the order of 0.1%, 0.2%, and 0.3%. The content of B 2O3 may also be 0%. By setting the content of B 2O3 to the above range, the specific gravity of the glass can be reduced, and the thermal stability of the glass can be improved.
In the optical glass of embodiment 4-1, the upper limit of the content of P 2O5 is preferably 1.5%, more preferably in the order of 1.4%, 1.3% and 1.2%. The lower limit of the content of P 2O5 is preferably 0%, more preferably in the order of 0.2%, 0.4%, and 0.6%. The content of P 2O5 may also be 0%. By setting the content of P 2O5 to the above range, an increase in the relative partial dispersion Pg, F can be suppressed, and the thermal stability of the glass can be maintained.
In the glass of embodiment 4-1, the upper limit of the content of Al 2O3 is preferably 5%, more preferably in the order of 4%, 3% and 2%. The content of Al 2O3 may be 0%. By setting the content of Al 2O3 to the above range, the devitrification resistance and thermal stability of the glass can be maintained.
In the optical glass of embodiment 4-1, the upper limit of the total content [ SiO 2+B2O3 ] of SiO 2 and B 2O3 is preferably 48.0%, more preferably in the order of 47.0%, 46.0%, 45.0%, 44.5%. The lower limit of the total content [ SiO 2+B2O3 ] is preferably 32.0%, more preferably in the order of 33.0%, 34.0%, 35.0%, 35.5%. By setting the total content [ SiO 2+B2O3 ] to the above range, the specific gravity of the glass can be reduced, the thermal stability of the glass can be improved, and further a desired optical constant can be obtained.
In the optical glass of embodiment 4-1, the upper limit of the total content [ SiO 2+B2O3+P2O5 ] of SiO 2、B2O3 and P 2O5 is preferably 48.0%, more preferably 47.0%, 46.0%, 45.0% and 44.5%. The lower limit of the total content [ SiO 2+B2O3+P2O5 ] is preferably 33.0%, more preferably 34.0%, 35.0%, 36.0%, 36.5%. By setting the total content [ SiO 2+B2O3+P2O5 ] to the above range, the specific gravity of the glass can be reduced, the thermal stability of the glass can be improved, and further a desired optical constant can be obtained.
In the optical glass according to embodiment 4-1, the upper limit of the content of TiO 2 is preferably 10%, more preferably in the order of 9.5%, 9% and 8.5%. The lower limit of the content of TiO 2 is preferably 0%, more preferably in the order of 1%, 2% and 3%. The content of TiO 2 may also be 0%. By making the content of TiO 2 within the above range, a desired optical constant can be achieved, and the raw material cost of the glass can be reduced.
In the optical glass of embodiment 4-1, the lower limit of the content of Nb 2O5 is preferably 45%, more preferably in the order of 44%, 43% and 42%. The upper limit of the content of Nb 2O5 is preferably 24%, more preferably in the order of 25%, 26%, and 27%. By setting the content of Nb 2O5 to the above range, a desired optical constant can be achieved, an increase in specific gravity can be suppressed, and relative partial dispersions Pg, F can be reduced.
In the optical glass of embodiment 4-1, the lower limit of the total content [ TiO 2+Nb2O5 ] of TiO 2 and Nb 2O5 is preferably 28%, more preferably 29%, 30% and 31%. The upper limit of the total content [ TiO 2+Nb2O5 ] is preferably 45%, more preferably 44%, 43% and 42%. By setting the total content [ TiO 2+Nb2O5 ] to the above range, a desired optical constant can be achieved.
In the glass of embodiment 4-1, the upper limit of the content of WO 3 is preferably 5%, more preferably in the order of 4%, 3% and 2%. The content of WO 3 may also be 0%. By setting the upper limit of the content of WO 3 to the above range, the transmittance can be improved, and the relative partial dispersions Pg, F and specific gravity can be reduced.
In embodiment 4-1, the upper limit of the content of Bi 2O3 is preferably 5%, and more preferably in the order of 4%, 3% and 2%. The lower limit of the content of Bi 2O3 is preferably 0%. The content of Bi 2O3 may be 0%. By setting the content of Bi 2O3 to the above range, the thermal stability of the glass can be improved, and the relative partial dispersions Pg, F and specific gravity can be reduced.
In the glass of embodiment 4-1, the lower limit of the content of ZrO 2 is preferably 0%, more preferably in the order of 1%, 2% and 3%. The upper limit of the content of ZrO 2 is preferably 12.5%, more preferably in the order of 12.2%, 11.8%, 11.4%. The content of ZrO 2 may be 0%. By setting the content of ZrO 2 to the above range, a desired optical constant can be achieved, and the relative partial dispersions Pg, F can be reduced.
In the glass of embodiment 4-1, the upper limit of the content of Li 2 O is preferably 10%, more preferably in the order of 9%, 8% and 7%. The lower limit of the content of Li 2 O is preferably 0%, more preferably in the order of 1%, 2%, 3%. The content of Li 2 O may be 0%. By setting the content of Li 2 O to the above range, a desired optical constant can be achieved, and chemical durability, weather resistance, and stability upon reheating can be maintained.
In the glass of embodiment 4-1, the upper limit of the Na 2 O content is preferably 15%, more preferably in the order of 14%, 13.5% and 13%. The lower limit of the Na 2 O content is preferably 4%, more preferably in the order of 4.5%, 5%, 5.5%. By setting the Na 2 O content to the above range, the relative partial dispersions Pg, F can be reduced.
In the glass of embodiment 4-1, the upper limit of the content of K 2 O is preferably 5%, more preferably in the order of 4.5%, 4%, 3.5%. The lower limit of the content of K 2 O is preferably 0%, more preferably in the order of 0.1%, 0.2% and 0.3%. The content of K 2 O may also be 0%. By making the content of K 2 O within the above range, the thermal stability of the glass can be improved.
In the glass of embodiment 4-1, the upper limit of the total content [ Li 2O+Na2O+K2 O ] of Li 2O、Na2 O and K 2 O is preferably 22%, and more preferably 21%, 20.5% and 20%. The lower limit of the total content is preferably 11%, more preferably in the order of 11.1%, 11.2%, 11.3%. By setting the total content to the above range, the meltability and thermal stability of the glass can be improved, and the liquid phase temperature can be reduced.
In the glass of embodiment 4-1, the upper limit of the content of Cs 2 O is preferably 5%, and more preferably 3%, 1% and 0.5% are further in this order. The lower limit of the content of Cs 2 O is preferably 0%.
Cs 2 O has an effect of improving the thermal stability of the glass, but when the content thereof is increased, chemical durability and weather resistance are reduced. Therefore, each content of Cs 2 O is preferably in the above range.
In the glass of embodiment 4-1, the upper limit of the MgO content is preferably 10%, more preferably in the order of 8%, 6%, 4% and 2%. The lower limit of the MgO content is preferably 0%. The MgO content may be 0%.
In the glass of embodiment 4-1, the upper limit of the CaO content is preferably 10%, more preferably in the order of 8%, 6%, 4% and 2%. The lower limit of the CaO content is preferably 0%. The CaO content may be 0%.
In the glass of embodiment 4-1, the upper limit of the SrO content is preferably 10%, more preferably in the order of 8%, 6%, 4% and 2%. The lower limit of the SrO content is preferably 0%. The SrO content may be 0%.
In the optical glass according to embodiment 4-1, the upper limit of the content of BaO is preferably 10%, more preferably in the order of 8%, 6%, 4% and 2%. The lower limit of the content of BaO is preferably 0%. The BaO content may also be 0%. By setting the content of BaO to the above range, an increase in specific gravity can be suppressed.
MgO, caO, srO, baO are glass components having an effect of improving the thermal stability and devitrification resistance of the glass. However, when the content of these glass components increases, the specific gravity increases, high dispersibility is impaired, and the thermal stability and devitrification resistance of the glass decrease. Therefore, the respective contents of these glass components are preferably within the above ranges.
In the glass of embodiment 4-1, the upper limit of the total content [ MgO+CaO+SrO+BaO ] of MgO, caO, srO and BaO is preferably 10%, and more preferably 7%, 6% and 5%. The lower limit of the total content is preferably 0%. The total content may also be 0%. By setting the total content to the above range, an increase in specific gravity can be suppressed, and thermal stability can be maintained without impeding high dispersion.
In the glass of embodiment 4-1, the upper limit of the ZnO content is preferably 10%, more preferably in the order of 5%, 4% and 3%. The lower limit of the ZnO content is preferably 0%. The ZnO content may be 0%.
ZnO is a glass component having an effect of improving the thermal stability of glass. However, if the content of ZnO is too large, the specific gravity increases. Therefore, the content of ZnO is preferably in the above range from the viewpoint of improving the thermal stability of the glass and maintaining a desired optical constant.
In the optical glass of embodiment 4-1, the upper limit of the content of La 2O3 is preferably 5%, and more preferably in the order of 4%, 3% and 2%. The lower limit of the content of La 2O3 is preferably 0%. The content of La 2O3 may be 0%. By setting the content of La 2O3 to the above range, a desired optical constant can be achieved, an increase in specific gravity can be suppressed, and relative partial dispersions Pg, F can be reduced.
In the glass of embodiment 4-1, the upper limit of the content of Y 2O3 is preferably 5%, more preferably in the order of 4%, 3% and 2%. The lower limit of the content of Y 2O3 is preferably 0%. The content of Y 2O3 may also be 0%.
When the content of Y 2O3 is too large, the thermal stability of the glass decreases and the glass becomes easily devitrified during production. Therefore, the content of Y 2O3 is preferably in the above range from the viewpoint of suppressing the decrease in the thermal stability of the glass.
In the glass of embodiment 4-1, the upper limit of the content of Ta 2O5 is preferably 5%, more preferably in the order of 4%, 3% and 2%. The lower limit of the content of Ta 2O5 is preferably 0%. The content of Ta 2O5 may also be 0%.
Ta 2O5 is a glass component having an effect of improving the thermal stability of glass, and is a component that causes the relative partial dispersion Pg, F to decrease. On the other hand, when the content of Ta 2O5 is increased, the thermal stability of the glass is lowered, and melting residues of the glass raw material are likely to occur when the glass is melted. In addition, the specific gravity increases. Therefore, the content of Ta 2O5 is preferably in the above range.
In the glass of embodiment 4-1, the content of Sc 2O3 is preferably 2% or less. The lower limit of the content of Sc 2O3 is preferably 0%.
In the glass of embodiment 4-1, the content of HfO 2 is preferably 2% or less. The lower limit of the content of HfO 2 is preferably 0%, more preferably in the order of 0.05% and 0.1%.
Sc 2O3、HfO2 is an expensive component having an effect of improving the high dispersibility of glass. Therefore, each content of Sc 2O3、HfO2 is preferably within the above range.
In the glass of embodiment 4-1, the content of Lu 2O3 is preferably 2% or less. The lower limit of the content of Lu 2O3 is preferably 0%.
Lu 2O3 has an effect of improving high dispersibility of glass, but is also a glass component that causes an increase in specific gravity of glass because of a large molecular weight. Therefore, the content of Lu 2O3 is preferably in the above range.
In the glass of embodiment 4-1, the content of GeO 2 is preferably 2% or less. The lower limit of the content of GeO 2 is preferably 0%.
GeO 2 has an effect of improving high dispersibility of glass, but is an extremely expensive component among commonly used glass components. Therefore, the content of GeO 2 is preferably in the above range from the viewpoint of reducing the manufacturing cost of the glass.
In the glass of embodiment 4-1, the content of Gd 2O3 is preferably 2% or less. The lower limit of the content of Gd 2O3 is preferably 0%.
When the content of Gd 2O3 is too large, the heat stability of the glass is lowered. When the content of Gd 2O3 is too large, the specific gravity of the glass increases. Therefore, the content of Gd 2O3 is preferably in the above range from the viewpoint of keeping the thermal stability of the glass well and suppressing the increase of specific gravity.
In the glass of embodiment 4-1, the content of Yb 2O3 is preferably 2% or less. The lower limit of the Yb 2O3 content is preferably 0%.
Yb 2O3 has a larger molecular weight than La 2O3、Gd2O3、Y2O3, and therefore, causes an increase in specific gravity of the glass. When the specific gravity of the glass increases, the mass of the optical element increases. For example, if a lens having a large mass is incorporated in an auto-focus type imaging lens, power required for driving the lens at the time of auto-focus increases, and battery consumption becomes severe. Therefore, it is preferable to reduce the content of Yb 2O3 to suppress an increase in specific gravity of the glass.
In addition, when the content of Yb 2O3 is too large, the thermal stability of the glass is lowered. The content of Yb 2O3 is preferably in the above range from the viewpoint of preventing a decrease in the thermal stability of the glass and suppressing an increase in specific gravity.
The glass of embodiment 4-1 is preferably composed mainly of the above-mentioned glass component, that is, siO 2、Na2 O as an essential component, B2O3、P2O5、Al2O3、TiO2、Nb2O5、WO3、Bi2O3、ZrO2、Li2O、K2O、Cs2O、MgO、CaO、SrO、BaO、ZnO、La2O3、Y2O3、Ta2O5、Sc2O3、HfO2、Lu2O3、GeO2、Gd2O3 and Yb 2O3 as optional components, and the total content of the above-mentioned glass component is preferably more than 95%, more preferably more than 98%, still more preferably more than 99%, still more preferably more than 99.5%.
The glass of embodiment 4-1 is preferably composed of the above glass components, but may contain other components within a range that does not interfere with the operation and effect of the invention of embodiment 4. In the invention of claim 4, the inclusion of unavoidable impurities is not excluded.
(Other Components)
In addition to the above components, the optical glass may contain Sb 2O3、CeO2 or the like in a small amount as a refining agent. The total amount of the clarifying agent (external proportion addition amount) is preferably set to 0% or more and less than 1%, more preferably set to 0% or more and 0.5% or less.
The external ratio added amount is a value expressed as weight percentage of the added amount of the fining agent when the total content of all glass components except the fining agent is set to 100%.
Pb, cd, as, th and the like are components that may cause environmental burden. Accordingly, the content of PbO, cdO, thO 2 is preferably 0 to 0.1%, more preferably 0 to 0.05%, still more preferably 0 to 0.01%, and particularly preferably substantially no PbO, cdO, thO 2.
The content of As 2O3 is preferably 0 to 0.1%, more preferably 0 to 0.05%, still more preferably 0 to 0.01%, and particularly preferably substantially no As 2O3.
In addition, the optical glass can obtain high transmittance in a wide range of the visible region. In order to effectively use such features, it is preferable that the coloring element is not contained. As elements of colorability, cu, co, ni, fe, cr, eu, nd, er, V and the like can be exemplified. The content of any element is preferably less than 100 mass ppm, more preferably 0 to 80 mass ppm, still more preferably 0 to 50 mass ppm, and particularly preferably substantially no element.
Ga, te, tb, and the like are components that do not require introduction, and are also expensive components. Accordingly, the content of Ga 2O3、TeO2、TbO2 in mass% is preferably 0 to 0.1%, more preferably 0 to 0.05%, still more preferably 0 to 0.01%, still more preferably 0 to 0.005%, still more preferably 0 to 0.001%, and particularly preferably substantially no content.
(Glass characteristics)
< Refractive index nd >)
In the optical glass of embodiment 4-1, the refractive index nd is preferably 1.690 to 1.760. The refractive index nd may be 1.695 to 1.755, or 1.700 to 1.750. The component that relatively increases the refractive index nd is Nb 2O5、TiO2、ZrO2、Ta2O5、La2O3. The component that relatively lowers the refractive index nd is SiO 2、B2O3、Li2O、Na2O、K2 O. By properly adjusting the content of these components, the refractive index nd can be controlled.
< Abbe number vd >)
In the optical glass of embodiment 4-1, the Abbe number vd is preferably 30 to 36. The Abbe number vd may be 30.5 to 35.8 or 31 to 35.5. The component that relatively decreases the abbe number vd is Nb 2O5、TiO2、ZrO2、Ta2O5. The component SiO2、B2O3、Li2O、Na2O、K2O、La2O3、BaO、CaO、SrO. which relatively increases the Abbe number vd is a component which can control the Abbe number vd by properly adjusting the content of the component.
< Specific gravity of glass >
The specific gravity of the optical glass according to embodiment 4-1 is preferably 3.40 or less, more preferably 3.35 or less, still more preferably 3.30 or less, and still more preferably 3.25 or less. The lower limit is not particularly limited as the specific gravity is smaller, but is generally about 3.10. The components that relatively increase the specific gravity are BaO, la 2O3、ZrO2、Nb2O5、Ta2O5, and the like. The component that relatively reduces the specific gravity is SiO 2、B2O3、Li2O、Na2O、K2 O or the like. The specific gravity can be controlled by adjusting the content of these components.
< Relative partial Dispersion Pg, F >)
The upper limit of the relative partial dispersion Pg, F of the optical glass of embodiment 4-1 is preferably 0.5980, and more preferably in the order of 0.5970, 0.5960, 0.5950,0.5940. The lower limit of the relative partial dispersion Pg, F is preferably 0.5780, and 0.5800, 0.5820, 0.5840, 0.5860 may be further used. By setting the relative partial dispersion Pg, F to the above range, an optical glass suitable for high-order chromatic aberration correction can be obtained. The relative partial dispersion Pg, F can be controlled by adjusting the content of SiO 2、B2O3、TiO2、Nb2O5 or the like.
The upper limit of the deviation Δpg of the relative partial dispersion Pg, F of the optical glass according to embodiment 4-1 is preferably 0.0030, and more preferably in the order of 0.0025, 0.0020, and 0.0015. In addition, when the deviation Δpg, F is low, the lower limit is preferably-0.0060, and further, -0.0050, -0.0040, -0.0030, -0.0020.
< Liquid phase temperature >)
The liquid phase temperature LT of the optical glass of embodiment 4-1 is preferably 1200℃or lower, more preferably 1190℃or lower, 1180℃or lower, and still more preferably 1170℃or lower. By setting the liquid phase temperature to the above range, the melting and forming temperatures of the glass can be reduced, and as a result, erosion of glass melting devices (e.g., a crucible, a stirrer for melting glass, etc.) in the melting step can be reduced. The lower limit of the liquid phase temperature LT is not particularly limited, but is generally about 1000 ℃. The liquidus temperature LT is determined based on the balance of the contents of all glass components. Among them, the content of SiO 2、B2O3、Li2O、Na2O、K2 O and the like has a large influence on the liquid phase temperature LT.
The liquid phase temperature was determined as follows. 10cc (10 ml) of glass was charged into a platinum crucible, melted at 1250 to 1400 ℃ for 15 to 30 minutes, cooled to a temperature below the glass transition temperature Tg, and the glass was charged into a melting furnace at a given temperature together with the platinum crucible and kept for 2 hours. The temperature was kept at 1000℃or higher, and at 5℃or 10℃intervals, the glass was cooled after 2 hours, and the presence or absence of crystals in the glass was observed with a 100-fold optical microscope. The minimum temperature at which no crystals precipitate was set to the liquid phase temperature.
< Glass transition temperature Tg >)
The upper limit of the glass transition temperature Tg of the optical glass according to embodiment 4-1 is preferably 670℃and more preferably 650℃and 630℃and 610 ℃. The lower limit of the glass transition temperature Tg is preferably 510℃and more preferably 520℃and 525℃and 530 ℃. The component that relatively lowers the glass transition temperature Tg is Li 2O、Na2O、K2 O or the like. The component that relatively increases the glass transition temperature Tg is La 2O3、ZrO2、Nb2O5 or the like. By properly adjusting the content of these components, the glass transition temperature Tg can be controlled.
< Stability upon reheat >
In the optical glass according to embodiment 4-1, the number of crystals observed per 1g is preferably 20 or less, more preferably 10 or less, when heated at the glass transition temperature Tg for 10 minutes and further heated at a temperature of 140 to 220℃higher than the Tg for 10 minutes.
The stability at the time of reheating was measured as follows. A glass sample having a size of 1cm by 0.8cm was heated in a1 st test furnace set to a glass transition temperature Tg of the glass sample for 10 minutes, and further heated in a 2 nd test furnace set to a temperature 140 to 220 ℃ higher than the glass transition temperature Tg for 10 minutes, and then the presence or absence of crystallization was confirmed by an optical microscope (observation magnification: 10 to 100 times). Then, the corresponding number of crystals per 1g was measured. In addition, the presence or absence of cloudiness of the glass was visually confirmed.
The optical glass according to embodiment 4-1 can be produced in the same manner as in embodiment 1. The optical element and the like may be manufactured in the same manner as in embodiment 1.
Embodiment 4-2
The optical glass according to embodiment 4-2 is characterized in that,
The mass ratio of the content of SiO 2 to the total content of Nb 2O5 and TiO 2 [ SiO 2/(Nb2O5+TiO2) ] is greater than 0.80,
The mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is greater than 0.7,
The mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] of the total content of SiO 2、B2O3 and P 2O5 to the total content of Li 2O、Na2 O and K 2 O is 1.45-4.55,
The mass ratio of Na 2 O content to the total content of Li 2O、Na2 O and K 2 O [ Na 2O/(Li2O+Na2O+K2 O) ] is 0.45 or more,
The total content of SiO 2 and Nb 2O5 [ SiO 2+Nb2O5 ] is 62-84%.
In the optical glass of embodiment 4-2, the mass ratio [ SiO 2/(Nb2O5+TiO2 ] of the content of SiO 2 to the total content of Nb 2O5 and TiO 2 is more than 0.80. The lower limit of the mass ratio [ SiO 2/(Nb2O5+TiO2) ] is preferably 0.83, more preferably in the order of 0.85, 0.86, 0.87, 0.88. The upper limit of the mass ratio [ SiO 2/(Nb2O5+TiO2) ] is preferably 1.50, more preferably in the order of 1.40, 1.30, 1.20. By setting the mass ratio [ SiO 2/(Nb2O5+TiO2) ] to the above range, crystallization of the glass can be suppressed, and an optical glass excellent in homogeneity and stability upon reheating can be obtained.
In the optical glass of embodiment 4-2, the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is more than 0.7. The lower limit of the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] is preferably 0.73, more preferably in the order of 0.75, 0.77, 0.79. The upper limit of the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] is preferably 1.15, more preferably in the order of 1.13, 1.11, and 1.09. By setting the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] within the above range, the liquid phase temperature can be reduced, and the thermal stability of the glass can be improved.
In the optical glass of embodiment 4-2, the mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] of the total content of SiO 2、B2O3 and P 2O5 to the total content of Li 2O、Na2 O and K 2 O is 1.45 to 4.55. The lower limit of the mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] is preferably 1.70, more preferably in the order of 1.72, 1.74, 1.76. The upper limit of the mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] is preferably 4.2, more preferably in the order of 4.0, 3.95, and 3.9. By setting the mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] to the above range, crystallization of the glass can be suppressed.
In the optical glass according to embodiment 4-2, the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] of the Na 2 O content to the total content of Li 2O、Na2 O and K 2 O is 0.45 or more. The lower limit of the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] is preferably 0.46, more preferably in the order of 0.47, 0.48, 0.49. The upper limit of the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] is preferably 0.97, and more preferably in the order of 0.96, 0.90, 0.85, 0.80, 0.75, 0.70. By setting the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] within the above range, the liquid phase temperature can be reduced, and the thermal stability of the glass can be improved. In addition, crystallization of the glass can be suppressed, and an optical glass excellent in homogeneity and stability upon reheating can be obtained.
In the optical glass of embodiment 4-2, the total content [ SiO 2+Nb2O5 ] of SiO 2 and Nb 2O5 is 62 to 84%. The lower limit of the total content [ SiO 2+Nb2O5 ] is preferably 63.0%, more preferably in the order of 63.5%, 64.0%, 64.5%. The upper limit of the total content [ SiO 2+Nb2O5 ] is preferably 83%, and more preferably 82.7%, 82.4%, and 82.1% are in this order. By setting the total content [ SiO 2+Nb2O5 ] to the above range, the liquid phase temperature can be reduced, and the thermal stability of the glass can be improved. Furthermore, crystallization of the glass can be suppressed.
In the optical glass of embodiment 4-2, the mass ratio of the content of SiO 2 to the content of Na 2 O [ SiO 2/Na2 O ] is preferably 2.5 to 8.5. The lower limit of the mass ratio [ SiO 2/Na2 O ] is more preferably 2.6, and further more preferably in the order of 2.65, 2.7, 2.75. The upper limit of the mass ratio [ SiO 2/Na2 O ] is more preferably 8.2, and further more preferably in the order of 8.0, 7.8, and 7.6. By setting the mass ratio [ SiO 2/Na2 O ] to the above range, an optical glass excellent in homogeneity and stability upon reheating can be obtained.
The optical glass according to embodiment 4-2 may have the same content and ratio of glass components as those of embodiment 4-1. The glass characteristics and the manufacturing of optical glass, optical element, and the like in embodiment 4-2 may be the same as those in embodiment 4-1.
Embodiment 4 to 3
The optical glass of embodiment 4-3 has an Abbe number vd of 30 to 36,
The specific gravity is not more than 3.4,
The relative partial dispersion Pg, F has a deviation ΔPg, F of 0.0030 or less.
In the optical glass according to embodiment 4-3, the Abbe number vd is 30 to 36. The Abbe number vd may be 30.5 to 35.8 or 31 to 35.5. The component that relatively decreases the abbe number vd is Nb 2O5、TiO2、ZrO2、Ta2O5. The component SiO2、B2O3、Li2O、Na2O、K2O、La2O3、BaO、CaO、SrO. which relatively increases the Abbe number vd is a component which can control the Abbe number vd by properly adjusting the content of the component.
In the optical glass of embodiments 4 to 3, the specific gravity is 3.4 or less. The specific gravity is preferably 3.35 or less, more preferably 3.30 or less, and still more preferably 3.25 or less. The lower limit is not particularly limited as the specific gravity is smaller, but is generally about 3.10.
In the optical glass according to embodiment 4 to 3, the deviation Δpg of the relative partial dispersion Pg, F is 0.0030 or less. The upper limit of the deviation Δpg, F is preferably 0.0025, and more preferably in the order of 0.0020 and 0.0015. In addition, when the deviation Δpg, F is low, the lower limit is preferably-0.0060, and further, -0.0050, -0.0040, -0.0030, -0.0020.
In general, the relative partial dispersion Pg, F tends to decrease with an increase in the abbe number vd. Therefore, for embodiments 4-3, the relative partial dispersion Pg, F is defined using Δpg, F described above, instead of the relative partial dispersion Pg, F itself. For example, when νd is set to be about 30, Δpg and F are set to be about 0.0030 or less, and when νd is set to be about 32, Δpg and F are set to be about 0.0010 or less, the abbe number νd can provide an optical glass suitable for high-order chromatic aberration correction. Further, the specific gravity is 3.4 or less, more preferably 3.25 or less, whereby the optical element can be made lightweight.
Next, preferred embodiments of the content and ratio of the glass component in the optical glass according to embodiments 4 to 3 will be described in detail.
In the optical glass of embodiment 4 to 3, the mass ratio [ SiO 2/(Nb2O5+TiO2 ] of the content of SiO 2 to the total content of Nb 2O5 and TiO 2 is preferably more than 0.80, and the lower limit thereof is more preferably in the order of 0.83, 0.85, 0.86, 0.87, and 0.88. The upper limit of the mass ratio [ SiO 2/(Nb2O5+TiO2) ] is preferably 1.50, more preferably in the order of 1.40, 1.30, 1.20. By setting the mass ratio [ SiO 2/(Nb2O5+TiO2) ] to the above range, crystallization of the glass can be suppressed, and an optical glass excellent in homogeneity and stability upon reheating can be obtained.
In the optical glass of embodiment 4 to 3, the mass ratio of the content of SiO 2 to the content of Na 2 O [ SiO 2/Na2 O ] is preferably 2.5 to 8.5. The lower limit of the mass ratio [ SiO 2/Na2 O ] is more preferably 2.6, and further more preferably in the order of 2.65, 2.7, 2.75. The upper limit of the mass ratio [ SiO 2/Na2 O ] is more preferably 8.2, and further more preferably in the order of 8.0, 7.8, and 7.6. By setting the mass ratio [ SiO 2/Na2 O ] to the above range, an optical glass excellent in homogeneity and stability upon reheating can be obtained.
In the optical glass of embodiment 4 to 3, the mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] of the total content of SiO 2、B2O3 and P 2O5 to the total content of Li 2O、Na2 O and K 2 O is preferably 1.45 to 4.55. The lower limit of the mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] is more preferably 1.70, and further more preferably in the order of 1.72, 1.74, 1.76. The upper limit of the mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] is more preferably 4.2, and further more preferably in the order of 4.0, 3.95, and 3.9. By setting the mass ratio [ (SiO 2+B2O3+P2O5)/(Li2O+Na2O+K2 O) ] to the above range, crystallization of the glass can be suppressed.
In the optical glass of embodiment 4 to 3, the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] of the Na 2 O content to the total content of Li 2O、Na2 O and K 2 O is preferably 0.45 or more. The lower limit of the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] is more preferably 0.46, and further more preferably in the order of 0.47, 0.48, 0.49. The upper limit of the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] is preferably 0.97, and more preferably in the order of 0.96, 0.90, 0.85, 0.80, 0.75, 0.70. By setting the mass ratio [ Na 2O/(Li2O+Na2O+K2 O) ] within the above range, the liquid phase temperature can be reduced, and the thermal stability of the glass can be improved. Furthermore, crystallization of the glass can be suppressed, and an optical glass excellent in homogeneity and stability upon reheating can be obtained.
In the optical glass of embodiment 4 to 3, the total content [ SiO 2+Nb2O5 ] of SiO 2 and Nb 2O5 is preferably 62 to 84%. The lower limit of the total content [ SiO 2+Nb2O5 ] is more preferably 63.0%, and further more preferably in the order of 63.5%, 64.0%, 64.5%. The upper limit of the total content [ SiO 2+Nb2O5 ] is more preferably 83%, and further more preferably 82.7%, 82.4% and 82.1% are in this order. By setting the total content [ SiO 2+Nb2O5 ] to the above range, the liquid phase temperature can be reduced, and the thermal stability of the glass can be improved. Furthermore, crystallization of the glass can be suppressed.
In the optical glass of embodiment 4 to 3, the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is preferably more than 0.7. The lower limit of the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] is more preferably 0.73, and further more preferably in the order of 0.75, 0.77, 0.79. The upper limit of the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] is preferably 1.15, more preferably in the order of 1.13, 1.11, and 1.09. By setting the mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] within the above range, the liquid phase temperature can be reduced, and the thermal stability of the glass can be improved.
The optical glass according to embodiment 4-3 may have the same content and ratio of glass components as those of embodiment 4-1. In addition, the glass characteristics other than those described above, the production of optical glass, the production of optical elements, and the like in embodiment 4-3 may be the same as those in embodiment 4-1.
In embodiment 4-3, any of the embodiments of embodiment 4-1 or embodiment 4-2 may be used.
Examples
Examples of the invention 1
Hereinafter, the invention 1 will be described in more detail with reference to examples. However, the invention of the 1 st aspect is not limited to the embodiment shown in the examples.
Example 1-1
Glass samples having glass compositions shown in tables 1-1 to 1-5 and 1-23 were prepared in the following procedure, and various evaluations were performed. In tables 1-1 to 1-5 and 1-23, the contents of glass components other than P 2O5 were shown to be constant in order to show the effects by the inclusion of P 2O5.
[ Production of optical glass ]
First, oxides, hydroxides, carbonates, and nitrates corresponding to the constituent components of the glass were prepared as raw materials, and the raw materials were weighed and blended so that the glass compositions of the obtained optical glass became the respective compositions shown in tables 1-1 to 1-5 and 1-23, and the raw materials were thoroughly mixed. The thus obtained raw materials (batch materials) were charged into a platinum crucible, heated at 1350 to 1400 ℃ for 2 hours to prepare molten glass, stirred to homogenize the molten glass, and after clarification, the molten glass was cast into a mold preheated to an appropriate temperature. The cast glass was subjected to a heat treatment at a temperature 100 ℃ lower than the glass transition temperature Tg for 30 minutes, and naturally cooled to room temperature in a furnace, thereby obtaining a glass sample.
[ Confirmation of glass component composition ]
The content of each glass component was measured by inductively coupled plasma emission spectrometry (ICP-AES) for the obtained glass sample, and it was confirmed that the glass sample was consistent with each composition shown in tables 1-1 to 1-5 and 1-23.
[ Processability ]
The obtained glass sample was cut and sliced to obtain a 10mm×10mm×8mm sample. The sample was placed in a heat treatment furnace set at a predetermined temperature, heated for 5 minutes, and then taken out to cool the glass sample. The end of the cooled glass sample was optically polished, and the inside of the glass sample was observed with an optical microscope (100-fold). The number of internal defects (bright spots) in the glass sample was counted and converted into the number corresponding to each g. The internal defects are set to a size in the range of 1 to 300. Mu.m. When the number of internal defects of a glass containing no P 2O5 among glasses having the same glass composition except for P 2O5 is I/g and the number of internal defects of a glass containing P 2O5 is Ip/g, ΔI=I-Ip is preferably 1.0/g or more. In the glass sample, no cracks or streaks were observed.
[ Measurement of optical Properties ]
The obtained glass sample was further annealed at a temperature around the glass transition temperature Tg for about 30 minutes to about 2 hours, and then cooled to room temperature in a furnace at a cooling rate of-30 ℃/hour, to obtain an annealed sample. The obtained annealed samples were measured for refractive indices nd, ng, nF and nC, abbe numbers vd, relative partial dispersion Pg, F, specific gravity, glass transition temperatures Tg, λ70 and λ5. The results are shown in tables 1-1 to 1-5 and 1-23.
(I) Refractive index nd, ng, nF, nC and Abbe number vd
For the above annealed sample, the refractive index nd, ng, nF, nC was measured by the refractive index measurement method of JIS standard JIS B7071-1, and the Abbe number vd was calculated based on the formula (1-7).
νd＝(nd-1)/(nF-nC)…(1-7)
(Ii) Relative partial dispersion Pg, F
The relative partial dispersion Pg, F was calculated based on the formula (1-6) using the refractive indices ng, nF, nC in the g-ray, F-ray, and C-ray.
Pg,F＝(ng-nF)/(nF-nC)…(1-6)
(Iii) Specific gravity
Specific gravity was determined by archimedes method.
(Iv) Glass transition temperature Tg
The glass transition temperature Tg was measured using a differential scanning calorimeter (DSC 3300 SA) manufactured by NETZSCH JAPAN company at a temperature increase rate of 10 ℃/min.
(v)λ70、λ5
The annealed samples were processed to have planes which were parallel to each other and optically polished, and the spectral transmittance was measured in a wavelength region of 280nm to 700 nm. The intensity of light perpendicularly entering one plane of the optical polishing was set as intensity a, and the intensity of light exiting the other plane was set as intensity B, so that the spectral transmittance B/a was calculated. The wavelength at which the spectral transmittance was 70% was λ70, and the wavelength at which the spectral transmittance was 5% was λ5. The spectral transmittance also includes reflection loss of light on the surface of the sample.
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Examples 1 to 2
Glass samples having glass compositions shown in tables 1-6 to 1-22 were prepared in the same manner as in example 1-1, and the glass composition was confirmed in the same manner as in example 1-1 to measure optical characteristics. The results are shown in tables 1-6 to 1-22. The fluoride content is described in terms of an external proportion. Regarding the workability, it was confirmed that the formability of any glass sample upon reheating was good.
[ Tables 1 to 6]
[ Tables 1 to 7]
[ Tables 1 to 8]
[ Tables 1 to 9]
[ Tables 1 to 10]
[ Tables 1 to 11]
[ Tables 1 to 12]
[ Tables 1 to 13]
[ Tables 1 to 14]
[ Tables 1 to 15]
[ Tables 1 to 16]
[ Tables 1 to 17]
[ Tables 1 to 18]
[ Tables 1 to 19]
[ Tables 1 to 20]
[ Tables 1 to 21]
[ Tables 1 to 22]
Examples 1 to 3
Using the optical glasses produced in examples 1-1 and 1-2, lens blanks were produced by a known method, and the lens blanks were processed by a known method such as grinding, so as to produce various lenses.
The optical lens is made of various lenses such as biconvex lens, biconcave lens, plano-convex lens, plano-concave lens, concave meniscus lens, convex meniscus lens and the like.
The various lenses are combined with lenses formed of other types of optical glass, whereby the secondary chromatic aberration can be corrected satisfactorily.
Further, since glass has a low specific gravity, each lens has a smaller weight than a lens having the same optical characteristics and size, and is suitable for use in various imaging devices, particularly for energy saving reasons. Similarly, prisms were produced using the various optical glasses produced in examples 1-1 and 1-2.
Example of the invention of No. 2
Hereinafter, the invention of claim 2 will be described in more detail with reference to examples. However, the invention of the 2 nd is not limited to the embodiment shown in the examples.
Example 2-1
Glass samples having glass compositions shown in tables 2-1 to 2-4 were prepared in the following procedure, and various evaluations were performed.
[ Production of optical glass ]
First, oxides, hydroxides, carbonates, and nitrates corresponding to the constituent components of the glass were prepared as raw materials, and the raw materials were weighed and blended so that the glass compositions of the obtained optical glass became the respective compositions shown in tables 2-1 to 2-4, and the raw materials were thoroughly mixed. The thus obtained raw materials (batch materials) were charged into a platinum crucible, heated at 1350 to 1450 ℃ for 2 to 5 hours, and then molten glass was produced, stirred to homogenize the glass, and after clarification, the molten glass was cast into a mold preheated to an appropriate temperature. The cast glass was subjected to a heat treatment at a temperature 100 ℃ lower than the glass transition temperature Tg for 30 minutes, and naturally cooled to room temperature in a furnace, thereby obtaining a glass sample.
[ Confirmation of glass component composition ]
The content of each glass component was measured by inductively coupled plasma emission spectrometry (ICP-AES) for the obtained glass sample, and it was confirmed that the composition was consistent with each composition shown in tables 2-1 to 2-4.
[ Measurement of optical Properties ]
The obtained glass sample was further annealed at a temperature around the glass transition temperature Tg for about 30 minutes to about 2 hours, and then cooled to room temperature in a furnace at a cooling rate of-30 ℃/hour, to obtain an annealed sample. The obtained annealed samples were measured for refractive indices nd, ng, nF and nC, abbe numbers vd, relative partial dispersion Pg, F, specific gravity, glass transition temperatures Tg, λ70 and λ5. The results are shown in tables 2-1 to 2-4.
(I) Refractive index nd, ng, nF, nC and Abbe number vd
For the above annealed samples, the refractive index nd, ng, nF, nC was measured by a refractive index measurement method of JIS standard JIS B7071-1, and the Abbe number vd was calculated based on the following formula.
νd＝(nd-1)/(nF-nC)
(Ii) Relative partial dispersion Pg, F
The relative partial dispersion Pg, F was calculated based on the following equation using the refractive indices ng, nF, nC in the g-ray, F-ray, and C-ray.
Pg,F＝(ng-nF)/(nF-nC)
(Iii) Deviation Δpg, F of relative partial dispersion Pg, F'
The relative partial dispersions Pg, F and abbe numbers vd are used to calculate the values based on the following formula.
ΔPg,F’＝Pg,F+(0.00286×νd)-0.68900
(Iv) Specific gravity
Specific gravity was determined by archimedes method.
(V) Glass transition temperature Tg
The glass transition temperature Tg was measured using a differential scanning calorimeter (DSC 3300 SA) manufactured by NETZSCH JAPAN company at a temperature increase rate of 10 ℃/min.
(ⅵ)λ70、λ5
The annealed samples were processed to have planes which were parallel to each other and optically polished, and the spectral transmittance was measured in a wavelength region of 280nm to 700 nm. The intensity of light perpendicularly entering one plane of the optical polishing was set as intensity a, and the intensity of light exiting the other plane was set as intensity B, so as to calculate spectral transmittance B/a. The spectral transmittance B/A was calculated by setting the wavelength at which the spectral transmittance was 70% to be λ70. The wavelength at which the spectral transmittance was 5% was set to λ5. The spectral transmittance also includes reflection loss of light on the surface of the sample.
[ Stability upon reheating ]
The obtained glass sample was cut to obtain fragments having a size of 10mm×10mm×7.5 mm. The pieces were heated in a test oven set to a temperature 200 to 220 ℃ higher than the glass transition temperature Tg of the glass sample for 5 minutes. The number of crystals per 1 piece of chips was measured by an optical microscope (observation magnification: 40 to 200 times). In addition, the presence or absence of crystallization was confirmed with naked eyes. The number of crystals corresponding to each 1 piece of chips was rated as a, the number of crystals corresponding to each 1 piece of chips was rated as B, and the number of crystals corresponding to each 1 piece of chips was rated as C. The results are shown in tables 2-1 to 2-4.
[ Table 2-1]
[ Table 2-2]
[ Tables 2 to 3]
[ Tables 2 to 4]
Examples 2 to 2
Using the optical glasses produced in example 2-1, lens blanks were produced by a known method, and the lens blanks were processed by a known method such as grinding, to produce various lenses.
The optical lens is made of various lenses such as biconvex lens, biconcave lens, plano-convex lens, plano-concave lens, concave meniscus lens, convex meniscus lens and the like.
The various lenses are combined with lenses formed of other types of optical glass, whereby the secondary chromatic aberration can be corrected satisfactorily.
Further, since glass has a low specific gravity, each lens has a smaller weight than a lens having the same optical characteristics and size, and is suitable for use in various imaging devices, particularly for energy saving reasons. Similarly, prisms were produced using the various optical glasses produced in example 2-1.
Example of the invention of 3 rd
Hereinafter, the 3 rd invention will be described in more detail with reference to examples. However, the invention of the 3 rd is not limited to the embodiment shown in the examples.
Example 3-1
Glass samples having glass compositions shown in tables 3-1 and 3-2-1 to 3-2-2 were prepared in the following procedure, and various evaluations were performed.
[ Production of optical glass ]
First, oxides, hydroxides, carbonates, and nitrates corresponding to the constituent components of the glass were prepared as raw materials, and the raw materials were weighed and blended so that the glass compositions of the obtained optical glass became the respective compositions shown in table 3-1, and the raw materials were thoroughly mixed. The thus obtained raw materials (batch materials) were charged into a platinum crucible, heated at 1350 to 1400 ℃ for 2 hours to prepare molten glass, stirred to homogenize the molten glass, and after clarification, the molten glass was cast into a mold preheated to an appropriate temperature. The cast glass was subjected to a heat treatment at a temperature 100 ℃ lower than the glass transition temperature Tg for 30 minutes, and naturally cooled to room temperature in a furnace, thereby obtaining a glass sample.
[ Confirmation of glass component composition ]
The content of each glass component was measured by inductively coupled plasma emission spectrometry (ICP-AES) for the obtained glass sample, and it was confirmed that each composition was consistent with that shown in Table 3-1.
[ Stability upon reheating ]
The obtained glass sample was cut into 1cm×1cm×0.8cm pieces, heated in a1 st test furnace set to a glass transition temperature Tg of the glass sample for 10 minutes, and further heated in a2 nd test furnace set to a temperature 140 to 250 ℃ higher than the glass transition temperature Tg thereof for 10 minutes. Then, the presence or absence of crystallization was confirmed by an optical microscope (observation magnification: 10 to 100 times). Then, the number of crystals was measured for each 1 g. The presence or absence of cloudiness in the glass was confirmed by the naked eye. The number of crystals corresponding to 1g was 20 or less, and no cloudiness was confirmed, and the number of crystals corresponding to 1g was more than 20, or at least one of cloudiness was confirmed, and was judged as "failure". The results are shown in tables 3-3-1 to 3-3-2.
[ Measurement of optical Properties ]
The obtained glass sample was further annealed at a temperature around the glass transition temperature Tg for about 30 minutes to about 2 hours, and then cooled to room temperature in a furnace at a cooling rate of-30 ℃/hour, to obtain an annealed sample. The obtained annealed samples were measured for refractive indices nd, ng, nF and nC, abbe numbers vd, relative partial dispersion Pg, F, specific gravity, glass transition temperatures Tg, λ80, λ70 and λ5. The results are shown in tables 3-3-1 to 3-3-2.
(I) Refractive index nd, ng, nF, nC and Abbe number vd
For the above annealed samples, the refractive index nd, ng, nF, nC was measured by a refractive index measurement method of JIS standard JIS B7071-1, and the Abbe number vd was calculated based on the following formula.
νd＝(nd-1)/(nF-nC)
(Ii) Relative partial dispersion Pg, F
The relative partial dispersion Pg, F was calculated based on the following equation using the refractive indices ng, nF, nC in the g-ray, F-ray, and C-ray.
Pg,F＝(ng-nF)/(nF-nC)
(Iii) Deviation Δpg, F of relative partial dispersion Pg, F
The relative partial dispersions Pg, F and abbe numbers vd are used to calculate the values based on the following formula.
ΔPg,F＝Pg,F+(0.0018×νd)-0.6483
(Iv) Specific gravity
Specific gravity was determined by archimedes method.
(V) Liquid phase temperature LT
The glass was placed in a furnace heated to a predetermined temperature, kept for about 2 hours, cooled, and then the inside of the glass was observed with a 40 to 100-fold optical microscope, and the liquid phase temperature was determined according to the presence or absence of crystallization.
(Vi) Glass transition temperature Tg
The glass transition temperature Tg was measured using a differential scanning calorimeter (DSC 3300 SA) manufactured by NETZSCH JAPAN company at a temperature increase rate of 10 ℃/min.
(vii)λ80、λ70、λ5
The annealed samples were processed to have planes which were parallel to each other and optically polished, and the spectral transmittance was measured in a wavelength region of 280nm to 700 nm. The intensity of light perpendicularly entering one plane of the optical polishing was set as intensity a, and the intensity of light exiting the other plane was set as intensity B, so as to calculate spectral transmittance B/a. The spectral transmittance B/A was calculated by setting the wavelength at which the spectral transmittance was 80% to be λ80. The wavelength at which the spectral transmittance was 70% was λ70, and the wavelength at which the spectral transmittance was 5% was λ5. The spectral transmittance also includes reflection loss of light on the surface of the sample.
[ Table 3-1]
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Example 3-2
Using the optical glasses produced in example 3-1, lens blanks were produced by a known method, and the lens blanks were processed by a known method such as grinding, to produce various lenses.
The optical lens is made of various lenses such as biconvex lens, biconcave lens, plano-convex lens, plano-concave lens, concave meniscus lens, convex meniscus lens and the like.
The various lenses are combined with lenses formed of other types of optical glass, whereby the secondary chromatic aberration can be corrected satisfactorily.
Further, since glass has a low specific gravity, each lens has a smaller weight than a lens having the same optical characteristics and size, and is suitable for use in various imaging devices, particularly for energy saving reasons. Similarly, prisms were produced using the various optical glasses produced in example 3-1.
Example of the 4 th invention
Hereinafter, the 4 th invention will be described in more detail with reference to examples. However, the 4 th invention is not limited to the embodiment shown in the examples.
Example 4-1
Glass samples having glass compositions shown in tables 4-1 to 4-4 were prepared in the following procedure, and various evaluations were performed.
[ Production of optical glass ]
First, oxides, hydroxides, carbonates, and nitrates corresponding to the constituent components of the glass were prepared as raw materials, and the raw materials were weighed and blended so that the glass compositions of the obtained optical glass became the respective compositions shown in tables 4-1 to 4-4, and the raw materials were thoroughly mixed. The thus obtained raw materials (batch materials) were charged into a platinum crucible, heated at 1350 to 1450 ℃ for 2 to 3 hours to prepare molten glass, stirred to homogenize the molten glass, and after clarification, the molten glass was cast into a mold preheated to an appropriate temperature. The cast glass was subjected to a heat treatment at a glass transition temperature tg±10 ℃ for 30 minutes, and naturally cooled to room temperature in a furnace, thereby obtaining a glass sample.
[ Confirmation of glass component composition ]
The content of each glass component was measured by inductively coupled plasma emission spectrometry (ICP-AES) for the obtained glass sample, and it was confirmed that the composition was consistent with each composition shown in tables 4-1 to 4-4.
[ Measurement of optical Properties ]
The obtained glass sample was further annealed at a temperature around the glass transition temperature Tg for about 30 minutes to about 2 hours, and then cooled to room temperature in a furnace at a cooling rate of-30 ℃/hour, to obtain an annealed sample. The obtained annealed samples were measured for refractive indices nd, ng, nF and nC, abbe numbers vd, relative partial dispersion Pg, F, deviation Δpg, F, specific gravity, glass transition temperatures Tg, λ80, λ70 and λ5. The results are shown in tables 4-1 to 4-4. Since the glass sample obtained in comparative example A, B was found to have a significant streak and to be very heterogeneous, the refractive index nd, abbe number vd, relative partial dispersion Pg, F, and deviation Δpg, F could not be measured.
(I) Refractive index nd, ng, nF, nC and Abbe number vd
For the above annealed samples, the refractive index nd, ng, nF, nC was measured by a refractive index measurement method of JIS standard JIS B7071-1, and the Abbe number vd was calculated based on the following formula.
νd＝(nd-1)/(nF-nC)
(Ii) Relative partial dispersion Pg, F
The relative partial dispersion Pg, F was calculated based on the following equation using the refractive indices ng, nF, nC in the g-ray, F-ray, and C-ray.
Pg,F＝(ng-nF)/(nF-nC)
(Iii) Deviation Δpg, F of relative partial dispersion Pg, F
The relative partial dispersions Pg, F and abbe numbers vd are used to calculate the values based on the following formula.
ΔPg,F＝Pg,F+(0.0018×νd)-0.6483
(Iv) Specific gravity
Specific gravity was determined by archimedes method.
(V) liquid phase temperature LT
The glass was placed in a furnace heated to a predetermined temperature, kept for about 2 hours, cooled, and then the inside of the glass was observed with a 40 to 100-fold optical microscope, and the liquid phase temperature was determined according to the presence or absence of crystallization.
(Vi) Glass transition temperature Tg
The glass transition temperature Tg was measured using a differential scanning calorimeter (DSC 3300 SA) manufactured by NETZSCH JAPAN company at a temperature increase rate of 10 ℃/min.
(vii)λ80、λ70、λ5
The annealed samples were processed to have planes which were parallel to each other and optically polished, and the spectral transmittance was measured in a wavelength region of 280nm to 700 nm. The intensity of light perpendicularly entering one plane of the optical polishing was set as intensity a, and the intensity of light exiting the other plane was set as intensity B, so as to calculate spectral transmittance B/a. The spectral transmittance B/A was calculated by setting the wavelength at which the spectral transmittance was 80% to be λ80. The wavelength at which the spectral transmittance was 70% was λ70, and the wavelength at which the spectral transmittance was 5% was λ5. The spectral transmittance also includes reflection loss of light on the surface of the sample.
[ Stability upon reheating ]
The obtained glass sample was cut into 1cm×1cm×0.8cm pieces, heated in a 1 st test furnace set to a glass transition temperature Tg of the glass sample for 10 minutes, and further heated in a 2 nd test furnace set to a temperature 140 to 220 ℃ higher than the glass transition temperature Tg thereof for 10 minutes. Then, the presence or absence of crystallization was confirmed by an optical microscope (observation magnification: 10 to 100 times). Then, the corresponding number of crystals per 1g was measured. The presence or absence of cloudiness in the glass was visually confirmed. The case where the number of crystals per 1g was 20 or less and no cloudiness was confirmed was judged as "good", the case where 21 to 60 crystals per 1g was confirmed was judged as "good", the case where the number of crystals per 1g was more than 60 crystals per 1g was confirmed, or the case where cloudiness or crystals were confirmed by naked eyes was judged as "bad".
[ Evaluation of vitrification ]
The presence or absence of crystallization was confirmed by naked eyes or an optical microscope (observation magnification: 40 times) for the obtained glass sample, and if no crystallization was found, the glass sample was evaluated as "acceptable", and if any, the glass sample was evaluated as "unacceptable".
Each of the optical glasses of example 4-1 was also homogeneous optically, and no streak was observed. On the other hand, on each of the glasses of comparative examples A and B produced under the same conditions as in example 4-1, a remarkable streak and a very uneven appearance were observed. The crystallization was also confirmed with the naked eye in comparative example C.
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Example 4-2
Using the optical glasses produced in example 4-1, lens blanks were produced by a known method, and the lens blanks were processed by a known method such as grinding, to produce various lenses.
The optical lens is made of various lenses such as biconvex lens, biconcave lens, plano-convex lens, plano-concave lens, concave meniscus lens, convex meniscus lens and the like.
The various lenses are combined with lenses formed of other types of optical glass, whereby the secondary chromatic aberration can be corrected satisfactorily.
Further, since glass has a low specific gravity, each lens has a smaller weight than a lens having the same optical characteristics and size, and is suitable for use in various imaging devices, particularly for energy saving reasons. Similarly, prisms were produced using the various optical glasses produced in example 4-1.
It should be understood that the embodiments disclosed herein are illustrative in all respects and are not to be construed as limiting. The scope of the invention is indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.
For example, by adjusting the composition of the glass illustrated in the above description, the optical glass according to one embodiment of the invention 1 to 4 can be manufactured.
It is needless to say that 2 or more of the matters described in the description or as preferable ranges may be arbitrarily combined.
Claims (15)
1. An optical glass having an Abbe number vd of 30 to 36, a specific gravity of 3.19 or less, and a deviation DeltaPg of relative partial dispersion Pg, F of 0.0015 or less.
2. The optical glass according to claim 1, wherein,
The mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is 0.80 or more,
The total content of TiO 2 and BaO [ TiO 2 +BaO ] is less than 10 mass%,
The content of Ta 2O5 is 3 mass% or less,
The mass ratio of the total content R 2 O to the total content of the total content R 2 O and the total content R ' O [ R 2O/(R2 O+R ' O) ] is more than 0.80, the total content R 2 O is the total content of Li 2O、Na2 O and K 2 O, the total content R ' O is the total content of MgO, caO, srO and BaO,
The mass ratio of the content of ZnO to the content of Nb 2O5 [ ZnO/Nb 2O5 ] is less than 0.14.
3. The optical glass according to claim 1, wherein,
The mass ratio [ Ta 2O5/(TiO2+Nb2O5) ] of the content of Ta 2O5 to the total content of TiO 2 and Nb 2O5 is less than 0.3.
4. The optical glass according to claim 1, wherein,
The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 9 mass%.
5. The optical glass according to claim 1, wherein,
The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 1.1 mass%.
6. An optical glass, wherein,
The mass ratio of the content of SiO 2 to the content of Nb 2O5 [ SiO 2/Nb2O5 ] is more than 1.05,
The mass ratio [ ZrO 2/Nb2O5 ] of the content of ZrO 2 relative to the content of Nb 2O5 is more than 0.25,
The mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is greater than 0.65,
The total content of TiO 2 and BaO [ TiO 2 +BaO ] is less than 10 mass%,
The optical glass satisfies 1 or more of the following (a) and (b):
(a) The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 9 mass%,
(B) The mass ratio of the total content R 2 O to the total content of the total content R 2 O and the total content R ' O [ R 2O/(R2 O+R ' O) ] is greater than 0.6, the total content R 2 O being the total content of Li 2O、Na2 O and K 2 O, the total content R ' O being the total content of MgO, caO, srO and BaO.
7. The optical glass according to claim 6, wherein,
The mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is 0.80 or more,
The content of Ta 2O5 is 3 mass% or less,
The Abbe number vd of the optical glass is less than 35.8,
The mass ratio [ R 2O/(R2 O+R ' O) ] of the total content R 2 O to the total content R 2 O to the total content R ' O of the (b) is 0.80 or more, the total content R 2 O is the total content of Li 2O、Na2 O and K 2 O, and the total content R ' O is the total content of MgO, caO, srO and BaO.
8. The optical glass according to claim 6 or 7, wherein,
The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 9 mass%.
9. An optical glass, wherein,
The mass ratio of the content of SiO 2 to the content of Nb 2O5 [ SiO 2/Nb2O5 ] is more than 1.05,
The mass ratio [ ZrO 2/Nb2O5 ] of the content of ZrO 2 relative to the content of Nb 2O5 is more than 0.25,
The mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is greater than 0.65,
The total content of TiO 2 and BaO [ TiO 2 +BaO ] is less than 10 mass%,
The mass ratio of the content of Ta 2O5 to the total content of TiO 2 and Nb 2O5 [ Ta 2O5/(TiO2+Nb2O5) ] is less than 0.3,
The optical glass satisfies 1 or more of the following (c) and (d):
(c) The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 1.1 mass%,
(D) The mass ratio of the total content R 2 O to the total content of the total content R 2 O and the total content R ' O [ R 2O/(R2 O+R ' O) ] is greater than 0.05, the total content R 2 O being the total content of Li 2O、Na2 O and K 2 O, the total content R ' O being the total content of MgO, caO, srO and BaO.
10. The optical glass according to claim 9, wherein,
The mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is 0.80 or more,
The content of Ta 2O5 is 3 mass% or less,
The Abbe number vd of the optical glass is less than 35.8,
The mass ratio [ R 2O/(R2 O+R ' O) ] of the total content R 2 O to the total content R 2 O to the total content R ' O of the (d) is 0.80 or more, the total content R 2 O is the total content of Li 2O、Na2 O and K 2 O, and the total content R ' O is the total content of MgO, caO, srO and BaO.
11. The optical glass according to claim 9, wherein,
The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 1.1 mass%.
12. An optical glass, wherein,
The mass ratio of the content of SiO 2 to the content of Nb 2O5 [ SiO 2/Nb2O5 ] is more than 1.05,
The mass ratio [ ZrO 2/Nb2O5 ] of the content of ZrO 2 relative to the content of Nb 2O5 is more than 0.25,
The mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is greater than 0.65,
The total content of TiO 2 and BaO [ TiO 2 +BaO ] is less than 10 mass%,
The mass ratio of the content of ZnO to the content of Nb 2O5 [ ZnO/Nb 2O5 ] is less than 0.14,
The optical glass satisfies 1 or more of the following (e) and (f):
(e) The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 1.1 mass%,
(F) The mass ratio of the total content R 2 O to the total content of the total content R 2 O and the total content R ' O [ R 2O/(R2 O+R ' O) ] is greater than 0.05, the total content R 2 O being the total content of Li 2O、Na2 O and K 2 O, the total content R ' O being the total content of MgO, caO, srO and BaO.
13. The optical glass according to claim 12, wherein,
The mass ratio [ (TiO 2+Nb2O5)/(SiO2+B2O3) ] of the total content of TiO 2 and Nb 2O5 to the total content of SiO 2 and B 2O3 is 0.80 or more,
The content of Ta 2O5 is 3 mass% or less,
The Abbe number vd of the optical glass is less than 35.8,
The mass ratio [ R 2O/(R2 O+R ' O) ] of the total content R 2 O to the total content R 2 O to the total content R ' O of (f) is 0.80 or more, the total content R 2 O is the total content of Li 2O、Na2 O and K 2 O, and the total content R ' O is the total content of MgO, caO, srO and BaO.
14. The optical glass according to claim 12, wherein,
The total content R 2 O of Li 2O、Na2 O and K 2 O is more than 1.1 mass%.
15. An optical element formed from the optical glass of any one of claims 1 to 14.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017-109894 | 2017-06-02 | ||
| JP2017109894 | 2017-06-02 | ||
| JP2017249173 | 2017-12-26 | ||
| JP2017-249173 | 2017-12-26 | ||
| CN201880035996.6A CN110691760A (en) | 2017-06-02 | 2018-05-31 | Glass, optical glass and optical element |
| PCT/JP2018/021039 WO2018221678A1 (en) | 2017-06-02 | 2018-05-31 | Glass, optical glass, and optical element |
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| CN201880035996.6A Division CN110691760A (en) | 2017-06-02 | 2018-05-31 | Glass, optical glass and optical element |
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| CN201880035996.6A Pending CN110691760A (en) | 2017-06-02 | 2018-05-31 | Glass, optical glass and optical element |
| CN202410024188.7A Pending CN117945647A (en) | 2017-06-02 | 2018-05-31 | Glass, optical glass and optical element |
| CN202410024209.5A Pending CN117945648A (en) | 2017-06-02 | 2018-05-31 | Glass, optical glass and optical element |
| CN202410024229.2A Pending CN117945649A (en) | 2017-06-02 | 2018-05-31 | Glass, optical glass and optical element |
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| CN202410024150.XA Pending CN117945646A (en) | 2017-06-02 | 2018-05-31 | Glass, optical glass and optical element |
| CN201880035996.6A Pending CN110691760A (en) | 2017-06-02 | 2018-05-31 | Glass, optical glass and optical element |
| CN202410024188.7A Pending CN117945647A (en) | 2017-06-02 | 2018-05-31 | Glass, optical glass and optical element |
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| CN202410024229.2A Pending CN117945649A (en) | 2017-06-02 | 2018-05-31 | Glass, optical glass and optical element |
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| CN (5) | CN117945646A (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7334133B2 (en) | 2019-04-12 | 2023-08-28 | 株式会社オハラ | Optical glass, preforms and optical elements |
| CN112125511B (en) * | 2020-09-28 | 2022-04-12 | 成都光明光电股份有限公司 | Optical glass |
| CN112142324B (en) * | 2020-09-28 | 2022-04-15 | 成都光明光电股份有限公司 | Optical glass, glass preform and optical element |
| CN112142321B (en) * | 2020-09-28 | 2022-04-15 | 成都光明光电股份有限公司 | Optical glass, optical element and optical instrument |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3343418A1 (en) * | 1983-12-01 | 1985-06-20 | Schott Glaswerke, 6500 Mainz | OPTICAL GLASS WITH REFRACTION VALUES> = 1.90, PAYBACK> = 25 AND WITH HIGH CHEMICAL RESISTANCE |
| JP2561835B2 (en) * | 1987-04-23 | 1996-12-11 | 株式会社 オハラ | Optical glass |
| JP3269707B2 (en) * | 1992-08-03 | 2002-04-02 | カール−ツァイス−スティフツング | Eyeglasses and optical lightweight glass |
| DE102006052787B4 (en) * | 2005-12-23 | 2017-06-22 | Schott Ag | Optical glass |
| JP2011140434A (en) * | 2009-12-11 | 2011-07-21 | Ohara Inc | Optical glass, optical element and preform |
| JP2011121833A (en) * | 2009-12-11 | 2011-06-23 | Ohara Inc | Optical glass, optical element and preform |
| CN102206043B (en) * | 2010-03-18 | 2016-08-17 | 株式会社小原 | Optical glass, optical element and preformed articles |
| JP2011195369A (en) * | 2010-03-18 | 2011-10-06 | Ohara Inc | Optical glass, optical element, and preform |
| JP2011195370A (en) * | 2010-03-18 | 2011-10-06 | Ohara Inc | Optical glass, optical element, and preform |
| JP5808081B2 (en) * | 2010-03-18 | 2015-11-10 | 株式会社オハラ | Optical glass, optical element and preform |
| JP6014301B2 (en) * | 2010-06-24 | 2016-10-25 | 株式会社オハラ | Optical glass, preform and optical element |
| JP5863745B2 (en) * | 2012-12-07 | 2016-02-17 | 株式会社オハラ | Optical glass, preform and optical element |
| TWI658021B (en) * | 2012-12-07 | 2019-05-01 | 日商小原股份有限公司 | Optical glass, preform and optical element |
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- 2018-05-31 CN CN202410024150.XA patent/CN117945646A/en active Pending
- 2018-05-31 CN CN201880035996.6A patent/CN110691760A/en active Pending
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Also Published As
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| CN117945646A (en) | 2024-04-30 |
| JP2019104671A (en) | 2019-06-27 |
| CN117945647A (en) | 2024-04-30 |
| CN110691760A (en) | 2020-01-14 |
| JP7226927B2 (en) | 2023-02-21 |
| CN117945649A (en) | 2024-04-30 |
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