Optical glass, glass preform, optical element, and optical instrument

Abstract

The present application provides an optical glass with excellent anti-crystallization performance, lower transition temperature and relative partial dispersion. The optical glass contains, in terms of weight percentage, SiO2: 30-50%; Nb2O5: 25-38%; ZrO2: 1-10%; BaO: 3-15%; SrO: 3-13%; Li2O: 1-7%; Na2O: 2-9%; and K2O: 1-7%. Through reasonable component design, the optical glass obtained by the present application has excellent anti-crystallization performance, lower transition temperature and relative partial dispersion.

Description

TECHNICAL FIELD

[0001] The present application relates to an optical glass, in particular to an optical glass with a refractive index of 1.68-1.76 and an Abbe number of 31-38, and a glass preform, an optical element and an optical instrument made of the same. BACKGROUND

[0002] In recent years, with the rapid development of photoelectric products such as smart phones, single-lens reflex cameras and monitoring security, higher requirements are put forward for the performance of optical glasses. For example, it is desired in optical design that the optical glass has the performance of suitable elimination or as far as possible reduction of residual chromatic aberration of secondary spectrum, which requires the optical glass to have a relatively low relative partial dispersion (P g,F ).

[0003] Chinese patent CN101857358A discloses an optical glass with a refractive index of 1.69-1.82 and an Abbe number of 33-46, which has a relatively low relative partial dispersion, but the transition temperature of the glass is relatively high, which is not conducive to the manufacture of optical elements by precise mold pressing. Chinese patent CN101215086A discloses a low-melting point optical glass with a refractive index of 1.65-1.85 and an Abbe number of 20-35, which has a relatively low transition temperature, but the glass has poor anti-crystallization performance, which is not conducive to the secondary hot pressing forming of the glass. SUMMARY

[0004] The technical problem to be solved by the present application is to provide an optical glass with excellent anti-crystallization performance, a relatively low transition temperature and a relatively low relative partial dispersion.

[0005] The technical solution adopted by the present application to solve the technical problem is:

[0006] (1) An optical glass, the components of which are represented by weight percentage, comprising: SiO2: 30-50%; Nb2O5: 25-38%; ZrO2: 1-10%; BaO: 3-15%; SrO: 3-13%; Li2O: 1-7%; Na2O: 2-9%; K2O: 1-7%.

[0007] (2) The optical glass according to (1), the components of which are represented by weight percentage, further comprising: B2O3: 0-4%; and / or Al2O3: 0-3%; and / or TiO2: 0-3%; and / or Ln2O3: 0-4%, the Ln2O3 being one or more of La2O3, Gd2O3, Y2O3, Yb2O3; and / or ZnO: 0-5%; and / or CaO: 0-5%; and / or MgO: 0-5%; and / or P2O5: 0-3%; and / or a fining agent: 0-1%, the fining agent being one or more of Sb2O3, SnO, SnO2, CeO2.

[0008] (3) Optical glass consisting of, in terms of weight percentage, Si02: 30 to 50%; Nb205: 25 to 38%; Zr02: 1 to 10%; BaO: 3 to 15%; SrO: 3 to 13%; Li20: 1 to 7%; Na20: 2 to 9%; K20: 1 to 7%; B203: 0 to 4%; Al203: 0 to 3%; Ti02: 0 to 3%; Ln203: 0 to 4%; ZnO: 0 to 5%; CaO: 0 to 5%; MgO: 0 to 5%; P205: 0 to 3%; fining agent: 0 to 1%, the Ln203 being one or more of La203, Gd203, Y203, Yb203, and the fining agent being one or more of Sb203, SnO, Sn02, Ce02.

[0009] (4) Optical glass containing Si02, Nb205, Zr02, BaO, SrO, Li20, Na20, and K20 in its components, the optical glass having a refractive index n d of 1.68 to 1.76, an Abbe number v d of 31 to 38, a relative partial dispersion P g,F of 0.6000 or less, and a transition temperature T g of 630°C or lower.

[0010] (5) The optical glass according to (4), consisting of, in terms of weight percentage, Si02: 30 to 50%; and / or Nb205: 25 to 38%; and / or Zr02: 1 to 10%; and / or BaO: 3 to 15%; and / or SrO: 3 to 13%; and / or Li20: 1 to 7%; and / or Na20: 2 to 9%; and / or K20: 1 to 7%; and / or B203: 0 to 4%; and / or Al203: 0 to 3%; and / or Ti02: 0 to 3%; and / or Ln203: 0 to 4%; and / or ZnO: 0 to 5%; and / or CaO: 0 to 5%; and / or MgO: 0 to 5%; and / or P205: 0 to 3%; and / or fining agent: 0 to 1%, the Ln203 being one or more of La203, Gd203, Y203, Yb203, and the fining agent being one or more of Sb203, SnO, Sn02, Ce02.

[0011] (6) The optical glass according to any one of (1) to (5), consisting of, in terms of weight percentage, Si02 / Nb205: 0.9 to 1.8, preferably Si02 / Nb205: 1.0 to 1.6, more preferably Si02 / Nb205: 1.1 to 1.5.

[0012] (7) The optical glass according to any one of (1) to (5) has its components expressed as weight percentages, wherein: (Na2O+BaO) / (Li2O+SrO) is 0.4 to 5.0, preferably (Na2O+BaO) / (Li2O+SrO) is 0.5 to 3.5, more preferably (Na2O+BaO) / (Li2O+SrO) is 0.7 to 2.5, and even more preferably (Na2O+BaO) / (Li2O+SrO) is 0.9 to 2.0.

[0013] (8) The optical glass according to any one of (1) to (5) has its components expressed as weight percentages, wherein: (TiO2+B2O3+ZnO) / SrO is 1.3 or less, preferably (TiO2+B2O3+ZnO) / SrO is 1.0 or less, more preferably (TiO2+B2O3+ZnO) / SrO is 0.01 to 0.7, and even more preferably (TiO2+B2O3+ZnO) / SrO is 0.05 to 0.4.

[0014] (9) The optical glass according to any one of (1) to (5) has its components expressed as weight percentages, wherein: (B2O3+Ln2O3) / (MgO+SrO+CaO) is 1.5 or less, preferably (B2O3+Ln2O3) / (MgO+SrO+CaO) is 1.0 or less, more preferably (B2O3+Ln2O3) / (MgO+SrO+CaO) is 0.5 or less, and even more preferably (B2O3+Ln2O3) / (MgO+SrO+CaO) is 0.3 or less, wherein the Ln2O3 is one or more of La2O3, Gd2O3, Y2O3, and Yb2O3.

[0015] (10) The optical glass according to any one of (1) to (5), wherein the composition is expressed as a weight percentage, wherein: (Nb2O5+B2O3+ZnO) / (MgO+SrO+CaO+BaO) is 0.9 to 5.5, preferably (Nb2O5+B2O3+ZnO) / (MgO+SrO+CaO+BaO) is 1.0 to 5.0, more preferably (Nb2O5+B2O3+ZnO) / (MgO+SrO+CaO+BaO) is 1.2 to 4.0, and even more preferably (Nb2O5+B2O3+ZnO) /

[0016] (MgO+SrO+CaO+BaO) is 1.5 to 3.0.

[0017] (11) The optical glass according to any one of (1) to (5) has its composition expressed as a weight percentage, wherein: ZnO / ZrO2 is 1.0 or less, preferably ZnO / ZrO2 is greater than 0 but less than or equal to 0.8, more preferably ZnO / ZrO2 is 0.01 to 0.6, and even more preferably ZnO / ZrO2 is 0.05 to 0.5.

[0018] (12) The optical glass according to any one of (1) to (5) has its composition expressed as a weight percentage, wherein: (MgO+SrO+CaO+BaO) / (Nb2O5+TiO2) is 0.2 to 1.2, preferably (MgO+SrO+CaO+BaO) / (Nb2O5+TiO2) is 0.25 to 1.0, more preferably (MgO+SrO+CaO+BaO) / (Nb2O5+TiO2) is 0.3 to 0.8, and even more preferably (MgO+SrO+CaO+BaO) / (Nb2O5+TiO2) is 0.3 to 0.6.

[0019] (13) The optical glass according to any one of (1) to (5) has its components expressed as weight percentages, wherein: Li2O / (Na2O+K2O) is 0.1 to 2.0, preferably Li2O / (Na2O+K2O) is 0.2 to 1.5, more preferably Li2O / (Na2O+K2O) is 0.2 to 1.0, and even more preferably Li2O / (Na2O+K2O) is 0.3 to 0.7.

[0020] (14) The optical glass according to any one of (1) to (5) has its components expressed as weight percentages, wherein: (Li2O+Na2O+K2O) / SrO is 0.5 to 4.5, preferably (Li2O+Na2O+K2O) / SrO is 0.6 to 4.0, more preferably (Li2O+Na2O+K2O) / SrO is 0.8 to 3.0, and even more preferably (Li2O+Na2O+K2O) / SrO is 1.0 to 2.5.

[0021] (15) The optical glass according to any one of (1) to (5), wherein the composition is expressed in weight percentage, wherein: SiO2: 35-45%, preferably SiO2: 37-43%; and / or Nb2O5: 26-36%, preferably Nb2O5: 28-32%; and / or ZrO2: 3-8%, preferably ZrO2: 4-7%; and / or BaO: 4-11%, preferably BaO: 5-9%; and / or SrO: 4-10%, preferably SrO: 5-8%; and / or Li2O: 1-5%, preferably Li2O: 1-4%; and / or Na2O: 2-7%, preferably Na2O: 2-6%; and / or K2O: 1-5%, preferably K2O: 1-4%; and / or B2O3: 0-2%, preferably B2O3: 0-1%; and / or Al ... O3: 0-2%, preferably Al2O3: 0-1%; and / or TiO2: 0-2%, preferably TiO2: 0-1%; and / or Ln2O3: 0-2%, preferably Ln2O3: 0-1%; and / or ZnO: greater than 0 but less than or equal to 3%, preferably ZnO: 0.1-2%; and / or CaO: 0-3%, preferably CaO: 0-1%; and / or MgO: 0-3%, preferably MgO: 0-1%; and / or P2O5: 0-2%, preferably P2O5: 0-1%; and / or clarifying agent: 0-0.5%, preferably clarifying agent: 0-0.1%, wherein the Ln2O3 is one or more of La2O3, Gd2O3, Y2O3, and Yb2O3, and the clarifying agent is one or more of Sb2O3, SnO, SnO2, and CeO2.

[0022] (16) The optical glass according to any one of (1) to (5) is free from TiO2; and / or B2O3; and / or Al2O3; and / or CaO; and / or MgO; and / or P2O5; and / or La2O3; and / or Gd2O3; and / or Y2O3; and / or Yb2O3.

[0023] (17) The optical glass according to any one of (1) to (5), wherein the refractive index n of the optical glass is d The value is 1.68 to 1.76, preferably 1.69 to 1.75, more preferably 1.70 to 1.74, and / or the Abbe number v d The value is 31 to 38, preferably 32 to 37, and more preferably 33 to 36.

[0024] (18) The optical glass according to any one of (1) to (5), wherein the relative partial dispersion P of the optical glass g,F The density ρ is 0.6000 or less, preferably 0.5900 or less, more preferably 0.5860 or less; and / or the density ρ is 3.80 g / cm³. 3The preferred value is 3.60 g / cm³. 3 The following is a preferred value: 3.50 g / cm³ 3 The following; and / or transmittance τ within 400 nm 400nm The content is 88.0% or more, preferably 90.0% or more, more preferably 90.5% or more, even more preferably 91.0% or more, even more preferably 92.0% or more, and still even more preferably 92.5% or more; and / or the anti-crystallization performance is Grade B or above, preferably Grade A; and / or the coefficient of thermal expansion α 20 / 120℃ 90×10 -7 / K or less, preferably 85×10 -7 / K or less, preferably 80×10 -7 / K or less; and / or a foaming degree of A grade or higher, preferably A0 grade or higher; and / or a viscosity of 50 poise or less at 1400°C, preferably 35 poise or less, more preferably 20 poise or less; and / or a transition temperature T g The temperature is below 630°C, preferably below 620°C, and more preferably below 610°C.

[0025] (19) Glass preform, made of any of the optical glass described in (1) to (18).

[0026] (20) An optical element made of any of the optical glass described in (1) to (18) or made of the glass preform described in (19).

[0027] (21) An optical instrument containing any of the optical glass described in (1) to (18) and / or containing the optical element described in (20).

[0028] The beneficial effects of this invention are: through reasonable component design, the optical glass obtained by this invention has excellent anti-crystallization properties, as well as low transition temperature and relative partial dispersion. Detailed Implementation

[0029] The embodiments of the optical glass of the present invention will now be described in detail. However, the present invention is not limited to the embodiments described below, and appropriate modifications can be made to implement it within the scope of the purpose of the present invention. Furthermore, regarding repeated descriptions, although there are appropriate omissions, this will not limit the spirit of the invention. In the following text, the optical glass of the present invention will sometimes be simply referred to as glass.

[0030] Optical Glass

[0031] The composition range of each component in the optical glass of the present invention will be described below. In the present invention, unless otherwise specified, the content of each component and the total content are all expressed as a weight percentage (wt%), that is, the weight percentage of the content of each component and the total content relative to the total amount of glass material converted into oxide composition. Here, "converted into oxide composition" means that when the oxides, complex salts, and hydroxides used as raw materials for the optical glass of the present invention decompose and transform into oxides upon melting, the total amount of such oxides is taken as 100%.

[0032] Unless otherwise specified in the specific context, the numerical ranges listed in this invention include upper and lower limits, and "above" and "below" include endpoint values ​​and all integers and fractions included in the range, but are not limited to the specific values ​​listed when the range is defined. The term "and / or" as used herein is inclusive; for example, "A and / or B" means only A, or only B, or both A and B.

[0033] <Essential and Optional Components>

[0034] SiO2 is an essential component of the optical glass of the present invention and forms its framework. If its content is less than 30%, it is difficult to obtain stable glass, and the chemical stability and resistance to crystallization of the glass deteriorate. Therefore, the SiO2 content in the present invention is 30% or more, preferably 35% or more, and more preferably 37% or more. If the SiO2 content exceeds 50%, the meltability of the glass deteriorates, and it is difficult to obtain the desired optical constants. Therefore, the SiO2 content is 50% or less, preferably 45% or less, and more preferably 43% or less.

[0035] B2O3 improves the meltability of glass, but when its content is too high, the chemical stability of the glass deteriorates, the viscosity decreases, and volatilization increases, which is detrimental to the stable control of refractive index and dispersion. Furthermore, excessive B2O3 content is not conducive to improving the light transmittance of the glass of this invention. Therefore, the B2O3 content in this invention is 0-4%, preferably 0-2%, and more preferably 0-1%. In some embodiments, it is further preferred that it does not contain B2O3.

[0036] Al2O3 can improve the chemical stability of glass, but when its content exceeds 3%, the meltability and light transmittance of the glass deteriorate. Therefore, the content of Al2O3 in this invention is 0-3%, preferably 0-2%, and more preferably 0-1%. In some embodiments, it is further preferred that Al2O3 is not present.

[0037] ZrO2 can increase the refractive index of glass, improve its chemical stability, and regulate its relative partial dispersion. However, excessive ZrO2 content increases the difficulty of melting the glass, raises the melting temperature, and leads to the formation of inclusions and a decrease in light transmittance. Therefore, the ZrO2 content is 1–10%, preferably 3–8%, and more preferably 4–7%.

[0038] TiO2 improves the refractive index and dispersion of glass, and its appropriate content can make the glass more stable and reduce its viscosity. If the TiO2 content exceeds 3%, the tendency of the glass to crystallize increases, and the relative partial dispersion of the glass increases, resulting in a decrease in light transmittance. Therefore, in this invention, the TiO2 content is 3% or less, preferably 2% or less, and more preferably 1% or less. In some embodiments, it is further preferred that TiO2 is not present.

[0039] Nb₂O₅ is a component that improves the devitrification resistance, refractive index, and dispersion of glass, and obtains abnormal dispersion. If its content is too high, the thermal stability and light transmittance of the glass will decrease, and the liquidus temperature will tend to rise. Therefore, the Nb₂O₅ content in this invention is 25-38%, preferably 26-36%, and more preferably 28-32%.

[0040] In some embodiments, controlling the SiO2 / Nb2O5 ratio (SiO2 / Nb2O5) within the range of 0.9 to 1.8 helps the glass achieve a lower relative partial dispersion, while optimizing the high-temperature viscosity and chemical stability of the glass and preventing an increase in the glass's coefficient of thermal expansion. Therefore, a SiO2 / Nb2O5 ratio of 0.9 to 1.8 is preferred, a SiO2 / Nb2O5 ratio of 1.0 to 1.6 is more preferred, and a SiO2 / Nb2O5 ratio of 1.1 to 1.5 is even more preferred.

[0041] Ln2O3 (Ln2O3 is one or more of La2O3, Gd2O3, Y2O3, and Yb2O3) is a component that improves the refractive index and chemical stability of glass. By controlling the Ln2O3 content to below 4%, the devitrification resistance of the glass can be prevented from decreasing. Therefore, the Ln2O3 content is 4% or less, preferably 2% or less, and more preferably 1% or less. In some embodiments, it is further preferred that the glass does not contain La2O3; and / or does not contain Gd2O3; and / or does not contain Y2O3; and / or does not contain Yb2O3.

[0042] ZnO can adjust the refractive index and dispersion of glass, reduce its high-temperature viscosity and transition temperature, allowing it to be melted at lower temperatures and thus improving its light transmittance. However, excessive ZnO content increases the difficulty of glass forming and deteriorates its resistance to crystallization. Therefore, the ZnO content is 0–5%, preferably greater than 0 but less than or equal to 3%, and more preferably 0.1–2%.

[0043] In some embodiments, controlling the ratio of ZnO content to ZrO2 content (ZnO / ZrO2) to below 1.0 can optimize the coefficient of thermal expansion and high-temperature viscosity of the glass, and prevent the glass from exhibiting bubble formation and deteriorating relative partial dispersion. Therefore, it is preferable that the ZnO / ZrO2 ratio is below 1.0, more preferably greater than 0 but less than or equal to 0.8, further preferably 0.01 to 0.6, and even more preferably 0.05 to 0.5.

[0044] BaO can improve the abrasion resistance and hardness of glass, and reduce its temperature coefficient of refractive index and coefficient of thermal expansion. However, a high BaO content can lead to a decrease in the chemical stability of the glass. Therefore, the BaO content is 3–15%, preferably 4–11%, and more preferably 5–9%.

[0045] SrO can improve the anti-crystallization properties and chemical stability of glass, and reduce its density. However, because SrO is expensive, excessive content will increase the cost of glass. Therefore, the SrO content in this invention is 3-13%, preferably 4-10%, and more preferably 5-8%.

[0046] In some embodiments, controlling the ratio (TiO2+B2O3+ZnO) / SrO between the total content of TiO2, B2O3, and ZnO (TiO2+B2O3+ZnO) and the content of SrO (TiO2+B2O3+ZnO) / SrO) to below 1.3 can improve the bubble content and anti-crystallization properties of the glass and lower the glass transition temperature. Therefore, it is preferable that (TiO2+B2O3+ZnO) / SrO is below 1.3, more preferably (TiO2+B2O3+ZnO) / SrO is below 1.0, further preferably (TiO2+B2O3+ZnO) / SrO is 0.01 to 0.7, and even more preferably (TiO2+B2O3+ZnO) / SrO is 0.05 to 0.4.

[0047] CaO helps adjust the optical constants of glass, improve its processing properties, and reduce its density. However, excessive CaO content deteriorates the glass's resistance to crystallization. Therefore, the CaO content is limited to 5% or less, preferably 3% or less, and more preferably 1% or less. In some embodiments, it is further preferred that the glass does not contain CaO.

[0048] MgO helps improve the weather resistance of glass, but when the content is high, the refractive index of the glass is difficult to meet design requirements, the anti-crystallization performance and stability of the glass decrease, and the cost of the glass increases rapidly. Therefore, the MgO content is limited to 0-5%, preferably 0-3%, and more preferably 0-1%. In some embodiments, it is even more preferable that the glass does not contain MgO.

[0049] In some embodiments, the ratio (B2O3+Ln2O3) / (MgO+SrO+CaO) between the total content of B2O3 and Ln2O3 (B2O3+Ln2O3) and the total content of MgO, CaO, and SrO (MgO+SrO+CaO) is controlled to be 1.5 or less. This prevents the relative partial dispersion and density of the glass from increasing, thereby improving the light transmittance of the glass. Therefore, it is preferable that (B2O3+Ln2O3) / (MgO+SrO+CaO) is 1.5 or less, more preferably (B2O3+Ln2O3) / (MgO+SrO+CaO) is 1.0 or less, further preferably (B2O3+Ln2O3) / (MgO+SrO+CaO) is 0.5 or less, and even more preferably (B2O3+Ln2O3) / (MgO+SrO+CaO) is 0.3 or less.

[0050] In some embodiments, the ratio (Nb2O5+B2O3+ZnO) / (MgO+SrO+CaO+BaO) between the total content of Nb2O5, B2O3, and ZnO (Nb2O5+B2O3+ZnO) and the total content of MgO, CaO, SrO, and BaO (MgO+SrO+CaO+BaO) is controlled within the range of 0.9 to 5.5. This is beneficial for reducing the high-temperature viscosity and transition temperature of the glass and improving its chemical stability. Therefore, it is preferable that (Nb2O5+B2O3+ZnO) / (MgO+SrO+CaO+BaO) is 0.9 to 5.5, more preferably (Nb2O5+B2O3+ZnO) / (MgO+SrO+CaO+BaO) is 1.0 to 5.0, and even more preferably (Nb2O5+B2O3+ZnO) / (MgO+SrO+CaO+BaO) is 1.0 to 5.0.

[0051] The ratio of (MgO+SrO+CaO+BaO) is 1.2 to 4.0, and more preferably (Nb2O5+B2O3+ZnO) / (MgO+SrO+CaO+BaO) is 1.5 to 3.0.

[0052] In some embodiments, the ratio of the total content of MgO, CaO, SrO, and BaO (MgO+SrO+CaO+BaO) to the total content of Nb2O5 and TiO2 (Nb2O5+TiO2) (MgO+SrO+CaO+BaO) / (Nb2O5+TiO2) is controlled within the range of 0.2 to 1.2, which can optimize the bubble degree and thermal expansion coefficient of the glass and prevent the density and transition temperature of the glass from increasing. Therefore, the preferred ratio of (MgO+SrO+CaO+BaO) / (Nb2O5+TiO2) is 0.2 to 1.2, more preferably (MgO+SrO+CaO+BaO) / (Nb2O5+TiO2) is 0.25 to 1.0, even more preferably (MgO+SrO+CaO+BaO) / (Nb2O5+TiO2) is 0.3 to 0.8, and even more preferably (MgO+SrO+CaO+BaO) / (Nb2O5+TiO2) is 0.3 to 0.6.

[0053] Li₂O can lower the glass transition temperature, adjust the high-temperature viscosity of glass, and improve the melting properties of glass, but its high content is detrimental to the chemical stability of glass. Therefore, the Li₂O content in this invention is 1–7%, preferably 1–5%, and more preferably 1–4%.

[0054] Na₂O improves the melting properties of glass, enhancing the glass melting process and reducing relative partial dispersion. However, excessive Na₂O content reduces the chemical stability and weather resistance of the glass. Therefore, the Na₂O content is 2–9%, preferably 2–7%, and more preferably 2–6%.

[0055] In some embodiments, controlling the ratio of the total content of Na2O and BaO (Na2O+BaO) to the total content of Li2O and SrO (Li2O+SrO), (Na2O+BaO) / (Li2O+SrO), within the range of 0.4 to 5.0, allows the glass to maintain excellent anti-crystallization properties and high-temperature viscosity while preventing a decrease in light transmittance. Therefore, it is preferable that (Na2O+BaO) / (Li2O+SrO) is 0.4 to 5.0, more preferably 0.5 to 3.5, further preferably 0.7 to 2.5, and even more preferably 0.9 to 2.0.

[0056] K₂O improves the thermal stability and melt properties of glass, but if its content is too high, the glass's resistance to devitrification and chemical stability deteriorates. Therefore, the K₂O content in this invention is 1–7%, preferably 1–5%, and more preferably 1–4%.

[0057] In some embodiments, controlling the ratio of Li2O content to the total content of Na2O and K2O (Na2O+K2O), Li2O / (Na2O+K2O), within the range of 0.1 to 2.0, can improve the chemical stability and light transmittance of the glass and prevent a decrease in its anti-crystallization properties. Therefore, it is preferable that Li2O / (Na2O+K2O) is 0.1 to 2.0, more preferably 0.2 to 1.5, further preferably 0.2 to 1.0, and even more preferably 0.3 to 0.7.

[0058] In some embodiments, controlling the total content of Li2O, Na2O, and K2O, the ratio between Li2O+Na2O+K2O and SrO (Li2O+Na2O+K2O) / SrO is within the range of 0.5 to 4.5. This can optimize light transmittance while reducing the glass transition temperature and preventing the glass's high-temperature viscosity from increasing. Therefore, it is preferable that (Li2O+Na2O+K2O) / SrO is 0.5 to 4.5, more preferably (Li2O+Na2O+K2O) / SrO is 0.6 to 4.0, further preferably (Li2O+Na2O+K2O) / SrO is 0.8 to 3.0, and even more preferably (Li2O+Na2O+K2O) / SrO is 1.0 to 2.5.

[0059] P2O5 can adjust the Abbe number of glass, but for the glass in this system, a P2O5 content higher than 3% will form a large number of crystal nuclei in the glass, leading to a rapid deterioration of the glass's resistance to crystallization. Therefore, the P2O5 content is limited to 3% or less, preferably 2% or less, and more preferably 1% or less. In some embodiments, it is further preferred that the glass does not contain P2O5.

[0060] In this invention, one or more components selected from Sb₂O₃, SnO, SnO₂, and CeO₂ are used as clarifying agents, which can improve the clarification effect and bubble content of the glass. Preferably, the content of the clarifying agent is 0-0.5%, more preferably 0-0.1%. When the content of Sb₂O₃ exceeds 1%, the glass tends to have reduced clarification performance. At the same time, its strong oxidizing effect promotes the corrosion of platinum or platinum alloy vessels used for molten glass and the deterioration of the forming mold. Therefore, the content of Sb₂O₃ is preferably 0-1%, more preferably 0-0.5%, and even more preferably 0-0.1%. SnO and SnO₂ can also be used as clarifying agents, but when their content exceeds 1%, the tendency of glass coloring increases, or when the glass is heated, softened, and then molded or otherwise re-formed, Sn becomes the starting point for crystal nucleation, resulting in a tendency for devitrification. Therefore, the SnO2 content of the present invention is preferably 0-1%, more preferably 0-0.5%, and even more preferably 0-0.1%; the SnO content is preferably 0-1%, more preferably 0-0.5%, and even more preferably 0-0.1%. The function and content of CeO2 are the same as those of SnO2, and its content is preferably 0-1%, more preferably 0-0.5%, even more preferably 0-0.1%, and even more preferably does not contain CeO2.

[0061] <Components that should not be present>

[0062] In the glass of this invention, even if oxides of transition metals such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo are contained in small amounts, either alone or in combination, the glass will be colored and absorb at specific wavelengths in the visible light region, thereby weakening the property of this invention to improve visible light transmittance. Therefore, it is preferable that the glass does not contain these oxides, especially for optical glass where transmittance in the visible light region is required.

[0063] Oxides of Th, Cd, Tl, Os, Be, and Se have been increasingly subject to controlled use in recent years due to their status as hazardous chemicals. Environmental protection measures are essential not only in glass manufacturing but also in processing and post-product disposal. Therefore, given the importance of environmental impact, it is preferable to avoid the presence of these substances, except where their contamination is unavoidable. As a result, the optical glass becomes virtually free of pollutants. Therefore, the optical glass of this invention can be manufactured, processed, and disposed of even without special environmental countermeasures.

[0064] To achieve environmental friendliness, the optical glass of the present invention preferably does not contain As2O3 and PbO.

[0065] The terms "not containing" and "0%" as used herein mean that the compound, molecule, or element was not intentionally added to the optical glass of this invention as a raw material; however, as raw materials and / or equipment for producing optical glass, there may be certain impurities or components that are not intentionally added, which may be present in small or trace amounts in the final optical glass, and such cases are also within the scope of protection of this patent.

[0066] The performance of the optical glass of the present invention will now be described.

[0067] <Refractive Index and Abbe Number>

[0068] The refractive index (n) of optical glass d ) and Abbe number (ν d Test according to the method specified in GB / T 7962.1—2010.

[0069] In some embodiments, the refractive index (n) of the optical glass of the present invention d The lower limit is 1.68, the preferred lower limit is 1.69, and the more preferred lower limit is 1.70.

[0070] In some embodiments, the refractive index (n) of the optical glass of the present invention d The upper limit of ) is 1.76, the preferred upper limit is 1.75, and the more preferred upper limit is 1.74.

[0071] In some embodiments, the Abbe number (ν) of the optical glass of the present invention d The lower limit is 31, the preferred lower limit is 32, and the more preferred lower limit is 33.

[0072] In some embodiments, the Abbe number (ν) of the optical glass of the present invention d The upper limit of ) is 38, the preferred upper limit is 37, and the more preferred upper limit is 36.

[0073] <Density>

[0074] The density (ρ) of optical glass is tested according to the method specified in GB / T7962.20-2010.

[0075] In some embodiments, the density (ρ) of the optical glass of the present invention is 3.80 g / cm³. 3 The preferred value is 3.60 g / cm³. 3 The following is a preferred value: 3.50 g / cm³ 3 the following.

[0076] <400nm transmittance>

[0077] Transmittance of optical glass within 400nm (τ) 400nmAccording to the method specified in GB / T7962.12-2010, the thickness of the glass sample is 10 mm.

[0078] In some embodiments, the transmittance (τ) of the optical glass of the present invention within 400 nm is... 400nm The content is 88.0% or more, preferably 90.0% or more, more preferably 90.5% or more, even more preferably 91.0% or more, even more preferably 92.0% or more, and even more preferably 92.5% or more.

[0079] Relative Partial Dispersion

[0080] Relative partial dispersion (P) of optical glass g,F )=(n g -n F ) / (n F -n C ).

[0081] In some embodiments, the relative partial dispersion (P) of the optical glass of the present invention g,F The value is 0.6000 or less, preferably 0.5900 or less, and more preferably 0.5860 or less.

[0082] <Resistance to strong acids>

[0083] This invention uses the ability to resist strong acids to characterize the acid resistance / chemical stability of glass. The test method is to polish a 30×30×10mm glass sample on its large surface, immerse it in an acid solution with pH=2.0, and take it out every 5 hours to observe whether there are corrosion spots on the surface. The longer the time from immersion to the appearance of corrosion spots, the better the acid resistance of the glass.

[0084] In some embodiments, the time from immersion in the acid solution to the appearance of corrosion spots on the optical glass of the present invention is 60 hours or more, preferably 80 hours or more, and more preferably 100 hours or more.

[0085] Anti-crystallization properties

[0086] The anti-crystallization properties of the glass of this invention are tested using the following method:

[0087] The experimental glass sample was processed to a size of 20×20×10mm, polished on both sides, and then placed in a container at a temperature of T. g Hold the glass in a crystallization furnace at +200℃ for 30 minutes. After cooling, polish both surfaces. Judge the crystallization performance of the glass according to Table 1 below, with Grade A being the best and Grade E being the worst.

[0088] Table 1. Grading and Judgment Criteria for Crystallization

[0089] No. Class Standard 1 A No visible crystalline particles 2 B Few visible crystalline particles, small and scattered 3 C Visible larger scattered or small and more numerous crystalline particles 4 D Large and numerous crystalline particles 5 E Glass completely crystallized and opaque

[0090] In some embodiments, the anti-crystallization performance of the optical glass of the present invention is grade B or above, preferably grade A.

[0091] <Coefficient of thermal expansion>

[0092] The coefficient of thermal expansion of optical glass (α) 20 / 120℃ The data of optical glass at 20℃~120℃ were tested according to the method specified in GB / T 7962.16—2010.

[0093] In some embodiments, the coefficient of thermal expansion (α) of the optical glass of the present invention is... 20 / 120℃ ) is 90×10 -7 / K or less, preferably 85×10 -7 / K or less, preferably 80×10 -7 / K or below.

[0094] <Effervescence>

[0095] The bubble content of optical glass shall be tested according to the method specified in GB / T7962.8-2010.

[0096] In some embodiments, the bubble degree of the optical glass of the present invention is grade A or above, preferably grade A0 or above.

[0097] <High Temperature Viscosity>

[0098] The high-temperature viscosity of optical glass is tested using the following method: The high-temperature viscosity of glass is tested using the THETA Rheotronic II high-temperature viscometer with the rotation method. The unit of measurement is dPaS (poise). The smaller the value, the lower the viscosity.

[0099] In some embodiments, the viscosity of the optical glass of the present invention at 1400°C is 50 poise or less, preferably 35 poise or less, and more preferably 20 poise or less.

[0100] <Transition Temperature>

[0101] Transition temperature of optical glass (T) g The test shall be conducted in accordance with the method specified in GB / T7962.16-2010.

[0102] In some embodiments, the transition temperature (T) of the optical glass of the present invention is... g The temperature is below 630°C, preferably below 620°C, and more preferably below 610°C.

[0103] [Manufacturing methods for optical glass]

[0104] The manufacturing method of the optical glass of this invention is as follows: The glass of this invention is produced using conventional raw materials and processes, including but not limited to oxides, hydroxides, complex salts (such as carbonates, nitrates, sulfates, phosphates, metaphosphates, etc.), boric acid, etc., as raw materials. After being prepared according to conventional methods, the prepared furnace charge is put into a melting furnace (such as a platinum or platinum alloy crucible) at 1200-1500°C for melting. After clarification and homogenization, a homogeneous molten glass without bubbles and undissolved substances is obtained. This molten glass is then cast in a mold and annealed. Those skilled in the art can appropriately select raw materials, process methods, and process parameters according to actual needs.

[0105] [Glass preforms and optical components]

[0106] Glass preforms can be manufactured from the produced optical glass using methods such as direct drop forming, grinding, or hot pressing. Specifically, glass preforms can be manufactured by directly and precisely drop-forming molten optical glass into precision glass preforms, or by machining such as grinding and polishing, or by hot pressing a preform made from optical glass for compression molding followed by grinding. It should be noted that the methods for preparing glass preforms are not limited to the methods described above.

[0107] As described above, the optical glass of the present invention is useful for various optical components and optical designs. It is particularly preferred to form a preform from the optical glass of the present invention, and to use the preform for hot pressing, precision stamping, etc., to manufacture optical components such as lenses and prisms.

[0108] Both the glass preform and the optical element of the present invention are formed from the optical glass described above. The glass preform of the present invention possesses the excellent properties of optical glass; the optical element of the present invention possesses the excellent properties of optical glass, and can provide various optical elements such as lenses and prisms with high optical value.

[0109] Examples of lenses include concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, plano-concave lenses, and so on, where the lens surface is spherical or aspherical.

[0110] The optical glass of this invention can be used to manufacture optical components such as chemically strengthened imaging lenses.

[0111] [Optical Instruments]

[0112] The optical glass or optical elements formed from the optical glass of this invention can be used to manufacture optical instruments such as photographic equipment, video recording equipment, display equipment, and monitoring equipment. The optical glass or optical elements of this invention are suitable for use in automotive lighting instruments and optical equipment, and can be applied in automotive and other fields. The optical glass or optical elements of this invention are also suitable for use in optical instruments such as miniature projection, miniature imaging (video / photography), and miniature lighting.

[0113] Example

[0114] <Example of Optical Glass>

[0115] To further illustrate and explain the technical solution of the present invention, the following non-limiting embodiments are provided.

[0116] In this embodiment, optical glass with the composition shown in Tables 2 to 4 was obtained using the optical glass manufacturing method described above. Furthermore, the properties of each glass were measured using the testing method described in this invention, and the measurement results are shown in Tables 2 to 4.

[0117] Table 2.

[0118]

[0119]

[0120] Table 3.

[0121]

[0122]

[0123] Table 4.

[0124]

[0125]

[0126]

[0127] <Example of Glass Prefabricated Components>

[0128] The glass obtained from optical glass Examples 1 to 24# is used to manufacture preforms of various lenses and prisms, such as concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses, by means of grinding, hot pressing, precision stamping, or other molding methods.

[0129] <Optical Component Examples>

[0130] Annealing these preforms obtained from the above glass preform examples reduces internal stress in the glass while fine-tuning the refractive index, so that optical properties such as the refractive index reach the desired values.

[0131] Next, the prefabricated parts are ground and polished to produce various lenses and prisms, such as concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses. Anti-reflective coatings can also be applied to the surface of the resulting optical elements.

[0132] <Examples of Optical Instruments>

[0133] The optical elements obtained from the above-described optical element embodiments can be used, through optical design, to form optical components or optical assemblies by using one or more optical elements. These components can be used in, for example, imaging devices, sensors, microscopes, medical technology, digital projection, communications, optical communication technology / information transmission, optics / lighting in the automotive field, lithography technology, excimer lasers, wafers, computer chips, and integrated circuits and electronic devices that include such circuits and chips.

Claims

1. Optical glass, characterized in that, Its composition, expressed as a weight percentage, contains: SiO2: 30–50%; Nb2O5: 25–38%; ZrO2: 1–10%; BaO: 3–15%; SrO: 3–13%; Li2O: 1–7%; Na2O: 2–9%; K2O: 1–7%, (TiO2+B2O3+ZnO) / SrO is below 1.3, Li2O / (Na2O+K2O) is 0.1–0.85, (Li2O+Na2O+K2O) / SrO is 0.8–3.0, and the transmittance τ within 400 nm is... 400nm It is over 90.5%.

2. The optical glass according to claim 1, characterized in that, Its components, expressed as a weight percentage, also contain: B2O3: 0–4%; and / or Al2O3: 0–3%; and / or TiO2: 0–3%; and / or Ln2O3: 0–4%; and / or ZnO: 0–5%; and / or CaO: 0–5%; and / or MgO: 0–5%; and / or P2O5: 0–3%; and / or clarifying agent: 0–1%, wherein the Ln2O3 is one or more of La2O3, Gd2O3, Y2O3, and Yb2O3, and the clarifying agent is one or more of Sb2O3, SnO, SnO2, and CeO2.

3. Optical glass, characterized in that, Its composition, expressed as a weight percentage, is as follows: SiO2: 30–50%; Nb2O5: 25–38%; ZrO2: 1–10%; BaO: 3–15%; SrO: 3–13%; Li2O: 1–7%; Na2O: 2–9%; K2O: 1–7%; B2O3: 0–4%; Al2O3: 0–3%; TiO2: 0–3%; Ln2O3: 0–4%. ZnO: 0-5%; CaO: 0-5%; MgO: 0–5%; P2O5: 0–3%; clarifying agent: 0–1% composition; (TiO2+B2O3+ZnO) / SrO: below 1.3; Li2O / (Na2O+K2O): 0.1–0.85; (Li2O+Na2O+K2O) / SrO: 0.8–3.0; transmittance τ within 400 nm. 400nm The content is above 90.5%, wherein the Ln2O3 is one or more of La2O3, Gd2O3, Y2O3, and Yb2O3, and the clarifying agent is one or more of Sb2O3, SnO, SnO2, and CeO2.

4. The optical glass according to any one of claims 1 to 3, characterized in that, Its composition is expressed as a weight percentage, of which: SiO2 / Nb2O5 is 0.9 to 1.

8.

5. The optical glass according to any one of claims 1 to 3, characterized in that, Its composition is expressed as a weight percentage, of which: SiO2 / Nb2O5 is 1.0 to 1.

6.

6. The optical glass according to any one of claims 1 to 3, characterized in that, Its composition is expressed as a weight percentage, of which: SiO2 / Nb2O5 is 1.1 to 1.

5.

7. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, of which (Na2O+BaO) / (Li2O+SrO) is 0.4 to 5.

0.

8. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, of which (Na2O+BaO) / (Li2O+SrO) is 0.5 to 3.

5.

9. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, of which (Na2O+BaO) / (Li2O+SrO) is 0.7 to 2.

5.

10. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, of which (Na2O+BaO) / (Li2O+SrO) is 0.9 to 2.

0.

11. The optical glass according to any one of claims 1 to 3, characterized in that, Its composition is expressed as a weight percentage, wherein (TiO2+B2O3+ZnO) / SrO is less than 1.

0.

12. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, of which (TiO2+B2O3+ZnO) / SrO is 0.01 to 0.

7.

13. The optical glass according to any one of claims 1 to 3, characterized in that, Its composition is expressed as a weight percentage, of which (TiO2+B2O3+ZnO) / SrO is 0.05 to 0.

4.

14. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, wherein (B2O3+Ln2O3) / (MgO+SrO+CaO) is less than 1.5, and the Ln2O3 is one or more of La2O3, Gd2O3, Y2O3, and Yb2O3.

15. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, wherein (B2O3+Ln2O3) / (MgO+SrO+CaO) is less than 1.0, and the Ln2O3 is one or more of La2O3, Gd2O3, Y2O3, and Yb2O3.

16. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, wherein (B2O3+Ln2O3) / (MgO+SrO+CaO) is less than 0.5, and the Ln2O3 is one or more of La2O3, Gd2O3, Y2O3, and Yb2O3.

17. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, wherein (B2O3+Ln2O3) / (MgO+SrO+CaO) is less than 0.3, and the Ln2O3 is one or more of La2O3, Gd2O3, Y2O3, and Yb2O3.

18. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, of which (Nb2O5+B2O3+ZnO) / (MgO+SrO+CaO+BaO) is 0.9 to 5.

5.

19. The optical glass according to any one of claims 1 to 3, characterized in that, Its composition is expressed as a weight percentage, of which (Nb2O5+B2O3+ZnO) / (MgO+SrO+CaO+BaO) is 1.0 to 5.

0.

20. The optical glass according to any one of claims 1 to 3, characterized in that, Its composition is expressed as a weight percentage, of which (Nb2O5+B2O3+ZnO) / (MgO+SrO+CaO+BaO) is 1.2 to 4.

0.

21. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, of which (Nb2O5+B2O3+ZnO) / (MgO+SrO+CaO+BaO) is 1.5 to 3.

0.

22. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, of which ZnO / ZrO2 is less than 1.

0.

23. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, wherein ZnO / ZrO2 is greater than 0 but less than or equal to 0.

8.

24. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, of which ZnO / ZrO2 is 0.01 to 0.

6.

25. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, of which ZnO / ZrO2 is 0.05 to 0.

5.

26. The optical glass according to any one of claims 1 to 3, characterized in that, Its composition is expressed as a weight percentage, of which (MgO+SrO+CaO+BaO) / (Nb2O5+TiO2) is 0.2 to 1.

2.

27. The optical glass according to any one of claims 1 to 3, characterized in that, Its composition is expressed as a weight percentage, of which (MgO+SrO+CaO+BaO) / (Nb2O5+TiO2) is 0.25 to 1.

0.

28. The optical glass according to any one of claims 1 to 3, characterized in that, Its composition is expressed as a weight percentage, of which (MgO+SrO+CaO+BaO) / (Nb2O5+TiO2) is 0.3 to 0.

8.

29. The optical glass according to any one of claims 1 to 3, characterized in that, Its composition is expressed as a weight percentage, of which (MgO+SrO+CaO+BaO) / (Nb2O5+TiO2) is 0.3 to 0.

6.

30. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, of which: Li2O / (Na2O+K2O) is 0.2 to 0.

85.

31. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, of which: Li2O / (Na2O+K2O) is 0.3 to 0.

7.

32. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as a weight percentage, of which (Li2O+Na2O+K2O) / SrO is 1.0 to 2.

5.

33. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as weight percentages, wherein: SiO2: 35-45%; and / or Nb2O5: 26-36%; and / or ZrO2: 3-8%; and / or BaO: 4-11%; and / or SrO: 4-10%; and / or Li2O: 1-5%; and / or Na2O: 2-7%; and / or K2O: 1-5%; and / or B2O3: 0-2%; and / or Al2O3: 0-2%; and / or TiO2: 0 ~2%; and / or Ln2O3: 0~2%; and / or ZnO: greater than 0 but less than or equal to 3%; and / or CaO: 0~3%; and / or MgO: 0~3%; and / or P2O5: 0~2%; and / or clarifying agent: 0~0.5%, wherein the Ln2O3 is one or more of La2O3, Gd2O3, Y2O3, and Yb2O3, and the clarifying agent is one or more of Sb2O3, SnO, SnO2, and CeO2.

34. The optical glass according to any one of claims 1 to 3, characterized in that, Its components are expressed as weight percentages, wherein: SiO2: 37–43%; and / or Nb2O5: 28–32%; and / or ZrO2: 4–7%; and / or BaO: 5–9%; and / or SrO: 5–8%; and / or Li2O: 1–4%; and / or Na2O: 2–6%; and / or K2O: 1–4%; and / or B2O3: 0–1%; and / or Al2O3: 0–1%; and / or TiO2: 0-1%; and / or Ln2O3: 0-1%; and / or ZnO: 0.1-2%; and / or CaO: 0-1%; and / or MgO: 0-1%; and / or P2O5: 0-1%; and / or clarifying agent: 0-0.1%, wherein the Ln2O3 is one or more of La2O3, Gd2O3, Y2O3, and Yb2O3, and the clarifying agent is one or more of Sb2O3, SnO, SnO2, and CeO2.

35. The optical glass according to any one of claims 1 to 3, characterized in that, Its components do not contain TiO2; and / or B2O3; and / or Al2O3; and / or CaO; and / or MgO; and / or P2O5; and / or La2O3; and / or Gd2O3; and / or Y2O3; and / or Yb2O3.

36. The optical glass according to any one of claims 1 to 3, characterized in that, The refractive index n of the optical glass d The value is 1.68–1.76, and / or the Abbe number v. d The range is 31 to 38.

37. The optical glass according to any one of claims 1 to 3, characterized in that, The refractive index n of the optical glass d The value is 1.69–1.75, and / or the Abbe number v. d The values ​​are 32 to 37.

38. The optical glass according to any one of claims 1 to 3, characterized in that, The refractive index n of the optical glass d The value is 1.70–1.74, and / or the Abbe number v. d The range is 33 to 36.

39. The optical glass according to any one of claims 1 to 3, characterized in that, The relative partial dispersion P of the optical glass g,F The particle size is below 0.6000; and / or the density ρ is 3.80 g / cm³. 3 The following; and / or transmittance τ within 400 nm 400nm The purity is above 91.0%; and / or the anti-crystallization performance is above Grade B; and / or the coefficient of thermal expansion α 20 / 120℃ 90×10 -7 / K or below; and / or foaming degree of A or above; and / or viscosity of 50 poise or below at 1400℃; and / or transition temperature T g It is below 630℃.

40. The optical glass according to any one of claims 1 to 3, characterized in that, The relative partial dispersion P of the optical glass g,F The particle size distribution is below 0.5900; and / or the density ρ is 3.60 g / cm³. 3 The following; and / or transmittance τ within 400 nm 400nm The purity is above 92.0%; and / or the anti-crystallization performance is Grade A; and / or the coefficient of thermal expansion α 20 / 120℃ 85×10 -7 / K or below; and / or foaming degree of A0 or above; and / or viscosity of 35 poise or below at 1400℃; and / or transition temperature T g Below 620℃.

41. The optical glass according to any one of claims 1 to 3, characterized in that, The relative partial dispersion P of the optical glass g,F It is below 0.5860; and / or the density ρ is 3.50 g / cm³. 3 The following; and / or transmittance τ within 400 nm 400nm It is above 92.5%; and / or the coefficient of thermal expansion α 20 / 120℃ 80×10 -7 / K or below; and / or a viscosity of 20 poise or below at 1400°C; and / or a transition temperature T g It is below 610℃.

42. A glass precast component, characterized in that, It is made of the optical glass described in any one of claims 1 to 41.

43. An optical element, characterized in that, It is made of optical glass as described in any one of claims 1 to 41, or of glass preform as described in claim 42.

44. An optical instrument, characterized in that, It contains the optical glass according to any one of claims 1 to 41, and / or contains the optical element according to claim 43.

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