Glass for a light filter and a light filter
AssigneeKabushiki Kaisha Ohara
InventorNaoyuki Goto
Life of this patent
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Abstract
Glass for a light filter capable of preventing variation of refractive index in a band-pass filter has a coefficient of thermal expansion within a range from 90×10−7/° C. to 120×10−7/° C. within a temperature range from −20° C. to +70° C. and, preferably, Young's modulus of 75 GPa or over and Vickers hardness of 550 or over, and light transmittance for plate thickness of 10 mm of 90% or over within a wavelength range from 950 nm to 1600 nm.
Claims16
Glass for a light filter having a coefficient of thermal expansion within a range from 90×10−7/° C. to 120×10−7/° C. within a temperature range from −20° C. to +70° C.(.) and having a composition which comprises, in weight percent:
- one or more ingredients selected from the group consisting of SiO2, B2O3 and P2O5 in the total amount of 35-55%, wherein the upper limit of SiO2 is 41.5%;
- one or more ingredients selected from the group consisting of TiO2, La2O3, ZrO2, Nb2O5, Ta2O5, WO3 and Y2O3 in the total amount of 20-45%, wherein TiO2 is included within a range from 0 to 30% and ZrO2 is included within a range from 0 to 5%;
- one or more ingredients selected from the group consisting of MgO, CaO, SrO, BaO and ZnO in the total amount of 3% or more and less than 15%;
- Na2O within a range from 0 to 14.5%;
- and
- one or both of Sb2O3 and As2O3 in the total amount of 0-1%,
- said glass being substantially free of Al2O3, CdO and PbO.
Glass for a light filter having a coefficient of thermal expansion within a range from 90×10−7/° C. to 120×10−7/° C. within a temperature range from −20° C. to +70° C.(.) and having a composition which comprises, in weight percent:
- one or more ingredients selected from the group consisting of SiO2, B2O3 and P2O5 in the total amount of 35-55%, wherein the upper limit of SiO2 is 41.5%;
- TiO2 within a range from 0 to 30%;
- ZrO2 within a range from 0 to 5%;
- one or more ingredients selected from the group consisting of MgO, CaO, SrO, BaO and ZnO in the total amount of 3% or more and less than 15%;
- one or more ingredients selected from the group consisting of Li2O, Na2O and K2O in the total amount of 5-30%, wherein Na2O is included within a range from 0 to 14.5% and
- one or both of Sb2O3 and As2O3 in the total amount of 0-1%,
- said glass being substantially free of Al2O3, CdO and PbO.
10 A light filter which is made by forming a dielectric film on glass as defined in claim 6.
Glass for a light filter having a coefficient of thermal expansion within a range from 90×10−7/° C. to 120×10−7/° C. within a temperature range from −20° C. to +70° C.(.) and having a composition which comprises, in weight percent:
- one or more ingredients selected from the group consisting of SiO2, B2O3 and P2O5 in the total amount of 35-55%, wherein the upper limit of SiO2 is 41.5%;
- one or more ingredients selected from the group consisting of TiO2, La2O3, ZrO2, Nb2O5, Ta2O5, WO3 and Y2O3 in the total amount of 20-45%, wherein TiO2 is included within a range from 0 to 30%;
- one or more ingredients selected from the group consisting of MgO, CaO, SrO, BaO and ZnO in the total amount of 3% or more and less than 15%;
- one or more ingredients selected from the group consisting of Li2O, Na2O and K2O in the total amount of 5-30%, wherein Na2O is included within a range from 0 to 14.5%;
- and
- one or both of Sb2O3 and As2O3 in the total amount of 0-1%.
16 A light filter which is made by forming a dielectric film on glass as defined in claim 11.
Dependencies are inferred from the claim text.