High-refractive-index, low-density glass

Abstract

The invention relates to an optical glass with a refractive index of more than 1.85, glass articles comprising the optical glass and the use thereof, in particular in the fields of optics and lenses, meta-optics and in “Augmented Reality” (AR).

Description

[0001] The invention relates to an optical glass with a refractive index of more than 1.85, glass articles comprising the optical glass and the use thereof, in particular in the fields of optics and lenses, meta-optics and in “Augmented Reality” (AR).

[0002] The invention relates to lenses that can be used in the field of augmented reality (AR). For AR glasses, high-refractive-index lenses are advantageous because they increase the field of view (FoV). On the other hand, the density of such lenses often increases disproportionately with increasing refractive index. This means that even if it were possible to make wafers thinner for AR applications, the lenses would become significantly heavier, making prolonged wear of AR glasses uncomfortable. Since the trend is moving from headsets to standard eyeglass designs that are intended to be worn for extended periods or at all times, like regular glasses, it is necessary to make the glasses lighter.This weight reduction is also advantageous for many other applications, as camera lenses in the Digital Single Lens Reflex (DSLR) sector are very often either very bulky or very heavy, which also significantly increases the battery power requirements of the autofocus.

[0003] Some glasses in the prior art are derived from the niobium phosphate or titanium phosphate system, meaning they contain significant proportions of P₂O₅ and niobium or titanium. These glasses are sometimes very problematic to produce because oxygen loss, for example due to excessively high melting and refining temperatures in the already reducing phosphate system, leads to lower oxidation states. For niobium, this is an oxidation state below V, and for titanium, below IV. This can result in an intense brown to black coloration in the niobium system, or a blue, yellow-green to brown to black coloration in the titanium system. Additionally, titanium significantly increases the tendency to crystallize, which is a known problem in the heavy flint sector with existing high-refractive-index glasses, which then, for example, can no longer be repressed.Unlike niobium, even the highest oxidation state of titanium absorbs at the edge of the visible range, which at higher concentrations causes the well-known yellow tint of barium titanium silicates.

[0004] Furthermore, the niobium phosphate glass family – like the high-refractive-index heavy flint or lanthanum heavy flint families – not only tends towards interfacial crystallization but also exhibits very rapid crystal growth, which makes post-cooling (stress cooling or refractive index adjustment) critical for potentially pre-germinated glasses. In addition, the glass is known to be relatively brittle and therefore difficult to polish into very thin wafers.

[0005] On the other hand, the climate resistance, at least for niobium phosphate lenses, is relatively good despite the P₂O₅ content, and the density is very low for this high refractive index, which increases wearing comfort. These lens families are well-known in the literature.

[0006] The lanthanum heavy flint systems available on the market, which lie within a refractive index range of interest for AR applications, exhibit a significantly less favorable combination of refractive index n. dand density. The comparatively high density and higher Abbe number of these glasses are primarily due to high lanthanum oxide content. Furthermore, such glasses exhibit relatively high hardness, which increases wafer production costs due to long grinding times. In some cases, the raw glass costs are also significantly higher, as rare-earth raw materials such as tungsten oxide, tantalum oxide, and other expensive materials are used in their production. In the heavy flint sector, Nb₂O₅ is often the main driver of batch costs, while the other raw materials, even in optical grade, are relatively inexpensive in comparison. Furthermore, the available lanthanum heavy flint glasses are mostly free of alkali oxides and therefore cannot be chemically hardened. Depending on the application, however, it can be advantageous to increase the mechanical stability of potentially ever thinner optical components (e.g.,to increase the spectacle lenses) for AR applications through chemical hardening.

[0007] Many heavy flint glasses, such as P-SF glasses, in this region of the Abbe diagram are problematic due to their batch costs and, because of their high Bi₂O₃ content, are also very soft (and therefore scratch-sensitive). Furthermore, they exhibit a disadvantageous UV transmission edge, for example, an insufficiently steep UV edge and / or a UV edge shifted into the longer wavelength range of the spectrum. In particular, P-SF glasses are produced discontinuously in platinum crucibles and could lead to problems with platinum alloying and the reduction of Bi(III) to Bi(0) when produced in a trough.

[0008] As mentioned above, there are some more or less suitable glasses, which are mostly still in the range of too low refractive values ​​(typical heavy flint glasses) or are difficult to process or work with (typical lanthanum heavy flint glasses).

[0009] Furthermore, lead-free heavy flint glasses containing a comparatively high proportion of Nb₂O₅ are known from the prior art. Nb₂O₅ contributes significantly to the high refractive index of these glasses, but has a comparatively high density and high raw material costs.

[0010] One objective of this invention is to provide glasses that have a high refractive index n. d and have the lowest possible density. The glass should exhibit the highest possible transmission, be easily hot-formed, and be readily workable. Therefore, its hardness must not be too low (resulting in more scratches and microcracks), but also not too high (leading to longer grinding times and consequently, more microcracks). The glass should possess high chemical resistance and be economically producible.

[0011] In one aspect, this task is solved by an optical glass with a refractive index n. dof more than 1.85, a quotient of d of less than 35 and a temperature T max of not more than 1350°C, comprising at least SiO2 and TiO2, comprising less than 30.0 mol% SiO2, less than 2.0 mol% Nb2O5, less than 17 mol% BaO and less than 5.0 mol% Ln2O3, where Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3.

[0012] Within the scope of the invention, a TiO2- and SiO2-containing glass system was found which, compared to the glasses described above based on the niobium phosphate or titanium phosphate systems, is more stable with regard to achievable internal transmission, has a higher refractive index, and yet exhibits a relatively low density. Furthermore, the glass system exhibits higher hardness and lower batch costs than the described niobium phosphate glasses.

[0013] The optical glass according to the invention has a refractive index n d of more than 1.85 and preferably not more than 2.05.

[0014] In advantageous embodiments, the refractive index n is d at least 1.87, preferably at least 1.88, preferably at least 1.89, preferably at least 1.90, preferably more than 1.90, preferably at least 1.92 or at least 1.93, preferably at least 1.95, preferably at least 1.960, preferably at least 1.965, preferably at least 1.970, preferably at least 1.975, preferably at least 1.980 and preferably at least 1.985. An advantageous n d The upper limit can be 2.05, 2.050, 2.045, 2.040, 2.035, 2.030, 2.025, or 2.020. Overall, the refractive index is therefore advantageously in the range of more than 1.85 to 2.05. The refractive index n d is known to those skilled in the art and in particular denotes the refractive index at a wavelength of approximately 587.6 nm (wavelength of the d-line of helium). Those skilled in the art know how the refractive index n d can be determined.

[0015] The refractive index is preferably determined using a refractometer, particularly a V-block refractometer. Samples with a square or nearly square base (e.g., with dimensions of approximately 20 mm × 20 mm × 5 mm) are particularly suitable. When measuring with a V-block refractometer, the samples are typically placed in a V-shaped block prism with a known refractive index. The refraction of an incident light beam depends on the difference between the refractive index of the sample and the refractive index of the V-block prism, thus allowing the refractive index of the sample to be determined. The measurement is preferably performed at a temperature of 22°C.

[0016] According to the invention, the glass has an Abbe number, i.e. dispersion (ν d), from less than 35. In advantageous embodiments, the dispersion is less than 32, preferably less than 30 or less than 25, preferably less than 24 or less than 23 or less than 22 and / or more than 18, preferably more than 18.5, further preferably more than 19.0. The dispersion ν d is calculated in a known manner, in which the refractive values ​​n d (at approximately 587.6 nm), n F (at approximately 486 nm) and n c (at approximately 656 nm) can be determined using a refractometer and compared to each other: vd=(nd−1) / (nF−nC). Furthermore, the glass according to the invention has a temperature T max from ≤ 1350°C. T maxThe melting point (Tm) is a composition-dependent glass size and indicates the minimum temperature required in the melting process to produce a "pure" melt from the starting materials (e.g., raw materials, cullet, etc.). A "pure" melt is present when no melt remnants—such as incompletely melted raw materials—and no crystals are found in the melt. As explained earlier, the melting and refining temperatures should be as low as possible to prevent the introduction of refractory material into the glass and the coloration of the glass by polyvalent ions in low oxidation states. This allows for high pure transmission. Since the melting and refining temperatures cannot be chosen arbitrarily high due to the requirement of achieving the highest possible pure transmission, the melting temperature is limited, which is why the temperature point described here is also referred to as "Tm". max “is referred to as Tmax This is therefore the lowest temperature at which a pure, crystal-free melt can still be produced. Because of this relationship, T max a good measure of the liquidus temperature of the glass (see below).

[0017] Within the scope of the invention, T max The composition of a glass is systematically determined on a laboratory scale in a series of experiments by melting the same glass from the starting components in small crucibles with a volume of 20 ml each at different maximum temperatures, with temperature increments of 10°C. Starting with the lowest temperature and progressing to the highest, the melting result is then optically evaluated to determine whether a clear melt has formed or whether relics and / or crystals are still present in the glass.

[0018] The T determined in this way for a composition maxThe value could also be reproduced with laboratory melts in a larger volume (e.g., 1 liter). Furthermore, additional experiments showed that the temperature point T max only slightly above the liquidus temperature of the glass. It was deduced that the temperature point T, which can be determined using a simple laboratory procedure, max a good measure for the liquidus temperature of the glass, which is not precisely determined here.

[0019] In an advantageous embodiment of the invention, T amounts to max not more than 1330°C, advantageously not more than 1320°C, preferably not more than 1310°C, preferably not more than 1300°C. Some advantageous variants have a T max of no more than 1290°C or no more than 1280°C.

[0020] In an advantageous embodiment, the glass has a glass transition temperature T g from 500°C to 800°C. Preferably, T gmore than 540°C, advantageously more than 560°C, preferably more than 580°C and / or not more than 750°C, not more than 700°C or not more than 650°C. A higher temperature g This can be advantageous with regard to crystallization stability, as it reduces the temperature difference to T max The temperature difference is lower, and the glass reaches a stable, glassy state more quickly. However, the glasses can still be easily hot-formed and processed.

[0021] In an advantageous embodiment, the glass according to the invention has a molar ratio (TiO2+ZrO2+2*Nb2O5+2*Ta2O5+2*Al2O3+SiO2+B2O3) / (R2O+RO+2*Ln2O3) of 1.5-3.5, wherein R2O = Li2O, Na2O and / or K2O and RO = MgO, CaO, SrO and / or BaO and Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3. Regarding the ratio of the components TiO2, ZrO2, Nb2O5, Ta2O5, Al2O3, SiO2, and B2O3 to the components R2O, RO, and Ln2O3, it should be noted that the proportions must be selected such that the inventive condition (TiO2+ZrO2+2*Nb2O5+2*Ta2O5+2*Al2O3+SiO2+B2O3) / (R2O+RO+2*Ln2O3) of 1.5–3.5 is met. Higher ratios pose a risk of undesirable crystallization and / or discoloration of the glasses. Similarly, excessively low ratios also pose a risk of undesirable crystallization.Preferably, the glass according to the invention has a molar ratio (TiO2+ZrO2+2*Nb2O5+2*Ta2O5+2*Al2O3+SiO2+B2O3) / (R2O+RO+2*Ln2O3) of 1.8 to 3.2, more preferably of 2.0 to 3.0 and particularly preferably of 2.1 to 2.9.

[0022] In an advantageous embodiment, the glass according to the invention has a molar ratio (TiO2+ZrO2+2*Nb2O5+2*Ta2O5+2*Al2O3+SiO2+B2O3) / (R2O+Cs2O+RO+2*Ln2O3) of 1.5 - 3.5, wherein R2O = Li2O, Na2O and / or K2O and RO = MgO, CaO, SrO and / or BaO and Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3. Regarding the ratio of the components TiO2, ZrO2, Nb2O5, Ta2O5, Al2O3, SiO2, and B2O3 to the components R2O, Cs2O, RO, and Ln2O3, it should be noted that the proportions must be selected such that the inventive condition (TiO2+ZrO2+2*Nb2O5+2*Ta2O5+2*Al2O3+SiO2+B2O3) / (R2O+Cs2O+RO+2*Ln2O3) of 1.5–3.5 is met. Higher ratios pose a risk of undesirable crystallization and / or discoloration of the glasses. Similarly, excessively low ratios also pose a risk of undesirable crystallization.Preferably, the glass according to the invention has a molar ratio (TiO2+ZrO2+2*Nb2O5+2*Ta2O5+2*Al2O3+SiO2+B2O3) / (R2O+Cs2O+RO+2*Ln2O3) of 1.8 to 3.2, more preferably of 2.0 to 3.0 and particularly preferably of 2.1 to 2.9.

[0023] Preferably, the optical glass according to the invention has a density r of no more than 4.5 g / cm³. 3 , preferably not more than 4.3 g / cm³ 3 , preferably not more than 4.1 g / cm³ 3 , preferably not more than 4.0 g / cm² 3 , especially preferably not more than 3.90 g / cm² 3 and furthermore, particularly preferably not more than 3.85 g / cm² 3 or not more than 3.8 g / cm³ 3 Preferably, the density of the glass according to the invention is 3.0 g / cm³. 3 up to 4.5 g / cm³ 3 , preferably 3.2 g / cm³ 3 up to 4.3 g / cm³ 3 , preferably 3.5 g / cm³ 3 up to 4.1 g / cm³ 3 , especially preferred at 3.6 g / cm³ 3 up to 4.0 g / cm³3 or of 3.6 g / cm³ 3 up to 3.85 g / cm³ 3 or of 3.6 g / cm³ 3 up to 3.8 g / cm³ 3 .

[0024] Preferably, the glass has a ratio of density r to refractive index n. d (r / n d ) of not more than 2.0, preferably not more than 1.95 g / cm³ 3 In some advantageous embodiments, the glass has a ratio of density r to refractive index n. d (r / n d ) of no more than 1.90 g / cm³ 3 preferably not more than 1.89 g / cm³ 3 or not more than 1.88 g / cm³ 3 In some advantageous embodiments, the glass has a ratio of density r to refractive index n. d (r / n d ) of no more than 1.87 g / cm³ 3 , preferably not more than 1.86 g / cm³ 3 on.

[0025] Preferably the optical glass according to the invention has a ratio of Abbe number v dto density r (v d / r) of 4.5 cm 3 / g up to 7.5 cm 3 / g, preferably from 4.8 cm 3 / g up to 7.0 cm 3 / g or preferably from 4.9 cm 3 / g up to 6.5 cm 3 / g, especially preferred from 5.0 cm 3 / g up to 6.0 cm 3 / g on.

[0026] Preferably the glass has a product of Abbezahl v d and density r of less than 100 g / cm³ 3 , preferably less than 95 g / cm² 3 preferably less than 90 g / cm² 3 , especially less than 80 g / cm² 3 and preferably more than 50 g / cm² 3 , preferably more than 55 g / cm² 3 , preferably more than 60 g / cm² 3 , preferably more than 65 g / cm² 3 , especially preferred more than 70 g / cm² 3 .

[0027] According to the invention, the glass has a SiO2 content of less than 30.0 mol%. SiO2 is a glass former. The oxide contributes significantly to chemical resistance but also increases processing temperatures. If it is used in very large quantities, the refractive indices according to the invention cannot be achieved. Preferably, the glass contains at least 10.0 mol%, more preferably at least 12.0 mol%, more preferably at least 13.0 mol%, and particularly preferably at least 15.0 mol% SiO2. The glass has less than 30.0 mol%, more preferably not more than 28.0 mol%, more preferably not more than 25.0 mol%, and particularly preferably not more than 23.0 mol% SiO2. In advantageous embodiments, the glass contains SiO2 from 10.0 mol% to < 30.0 mol%, preferably 12.0 mol% to 28.0 mol%, preferably 13.0 mol% to 25.0 mol%, and more preferably 15.0 mol% to 23.0 mol%.

[0028] B₂O₃ also acts as a glass former. In the glass system according to the invention, it can contribute to reaching the temperature point T. max to reduce the B₂O₃ content. Preferably, the glass contains 0 mol% to 8.0 mol%, more preferably 0 mol% to 5.0 mol% or 1.0 mol% to 5.0 mol% B₂O₃. Some advantageous variants may contain at least 1.0 mol%, at least 1.5 mol%, or at least 2.0 mol% B₂O₃. Preferably, the B₂O₃ content is limited to no more than 7.0 mol%, more preferably no more than 6.5 mol%, more preferably no more than 5.0 mol%, more preferably no more than 4.0 mol%, and more preferably no more than 3.0 mol%. Some advantageous variants contain no more than 0.5 mol%, more preferably less than 0.1 mol% B₂O₃. Some advantageous variants are free of B₂O₃.

[0029] It is advantageous, on the one hand, not to choose the total amount of glass formers too low, as they stabilize the glass, and on the other hand, to limit the content in order to obtain a glass with a high refractive index. Therefore, the glass of this invention preferably has a total SiO2 and B2O3 content of 12.0 mol% to 28.0 mol%, more preferably 12.0 mol% to 25.0 mol%, and more preferably 15.0 mol% to 23.0 mol%.

[0030] The glass of the invention may contain Nb₂O₅; however, the use of Nb₂O₅ can lead to increased batch costs and a higher density of the glass. Therefore, according to the invention, the Nb₂O₅ content is limited to less than 2.0 mol%, preferably less than 1.5 mol%, more preferably less than 1.0 mol%, and particularly preferably less than 0.5 mol% Nb₂O₅. Preferred embodiments of the glass of the invention are essentially free of Nb₂O₅.

[0031] Preferably, the glass contains at least 35.0 mol%, more preferably at least 37.0 mol%, more preferably at least 40.0 mol%, or more preferably at least 43.0 mol% and / or not more than 65.0 mol%, more preferably not more than 61.0 mol% or not more than 60.0 mol%, and more preferably not more than 55.0 mol% TiO2. In some advantageous embodiments, the glass contains 35.0 mol% to 65.0 mol%, more preferably 40.0 mol% to 60.0 mol%, and more preferably 43.0 mol% to 55.0 mol% TiO2.

[0032] Preferably, the glass comprises BaO in addition to TiO2, wherein the glass preferably has a total BaO and TiO2 content of at least 35.0 mol%, preferably at least 40.0 mol% or at least 42.0 mol% or at least 45.0 mol%, more preferably at least 50.0 mol% and / or not more than 70.0 mol%, preferably not more than 65.0 mol%, preferably not more than 63.0 mol% or not more than 60.0 mol%.

[0033] Optionally, the glass may contain Al₂O₃. Al₂O₃ can contribute to the chemical resistance of the glass. The glass may contain 0 to 8.0 mol%, 0 to 5.0 mol%, up to 3.0 mol%, up to 2.0 mol%, or up to 1.0 mol% of Al₂O₃. Some advantageous embodiments contain less than 0.5 mol% of Al₂O₃. Preferred variants are free of Al₂O₃. Some advantageous variants may contain 0.5 mol% to 3.0 mol%, preferably 0.75 mol% to 2.5 mol%, or 2.0 mol% to 5.0 mol%.

[0034] The glass may contain ZrO₂. ZrO₂ contributes to achieving the high refractive index, but it also increases the glass's tendency to crystallize, so its content is preferably limited to no more than 7.5 mol%, more preferably no more than 6.5 mol%, and also more preferably no more than 5.5 mol% or no more than 5.0 mol%. In some advantageous embodiments, the glass contains at least 0.5 mol%, more preferably at least 1.5 mol%, more preferably at least 2.5 mol% or 3.0 mol% ZrO₂. In some embodiments, the glass contains 0.5 mol% to 7.5 mol%, more preferably 1.5 mol% to 6.5 mol%, more preferably 2.5 mol% to 5.5 mol%, and particularly preferably 3.0 mol% to 5.0 mol% ZrO₂. Some embodiments may be free of ZrO₂.

[0035] Preferably, the glass contains Li₂O, Na₂O, and / or K₂O. Preferably, the glass has a total R₂O content, where R₂O = Li₂O, Na₂O, and / or K₂O, of at least 1.0 mol%, more preferably at least 2.0 mol%, particularly preferably at least 3.0 mol% or at least 4.0 mol%, and / or not more than 20.0 mol%, preferably not more than 17.0 mol%, more preferably not more than 15 mol%, and particularly preferably not more than 14 mol%. Preferably, the glass has a total R₂O content of 1.0 mol% to 20 mol%, more preferably from 2.0 mol% to 17.0 mol%, more preferably from 3.0 mol% to 15.0 mol%, and also more preferably from 4.0 mol% to 14 mol%. The aforementioned alkali metal oxides contribute to good processability; however, excessively high concentrations can reduce chemical resistance and lower the refractive index too much. Some formulations may be R₂O-free.

[0036] In some advantageous embodiments, the glass comprises one of Li₂O, Na₂O, and K₂O. In some advantageous embodiments, the glass comprises at least two of Li₂O, Na₂O, and K₂O. In some advantageous embodiments, the glass comprises Na₂O and at least one of Li₂O and K₂O. In some embodiments, the glass comprises Li₂O, Na₂O, and K₂O.

[0037] In some embodiments, the glass contains Li₂O. Since Li₂O can attack the material of crucibles and tanks, its content is preferably limited. The Li₂O content is preferably in the range of 0 mol% to 10.0 mol%, more preferably from 0.5 mol% to 7.0 mol%, and more preferably from 1.0 mol% to 5.0 mol%, or from 1.5 mol% to 3.0 mol%, or up to 2.0 mol%. In some advantageous embodiments, the glass is free of Li₂O.

[0038] In advantageous embodiments, the glass contains Na₂O. The Na₂O content is preferably in the range of 0.5 mol% to 18.0 mol% or from 0.5 mol% to 15.0 mol%, more preferably from 1.0 mol% to 13.5 mol% or up to 12.5 mol%. In some advantageous embodiments, the glass contains at least 1.0 mol%, preferably at least 1.5 mol%, more preferably at least 2.0 mol%, at least 3.0 mol% and / or not more than 18.0 mol% or not more than 15.0 mol%, more preferably not more than 13.5 mol% or not more than 12.5 mol%, more preferably not more than 11.0 mol% Na₂O. In some advantageous embodiments, the glass may be free of Na₂O.

[0039] In some advantageous embodiments, the glass contains K₂O, wherein the K₂O content is less than 5.0 mol%, preferably less than 3.0 mol%, preferably in the range of more than 0 mol% to 5.0 mol%, and preferably from 0.5 mol% to 3.0 mol%. In some advantageous embodiments, the glass is free of K₂O.

[0040] In advantageous embodiments, the glass contains at least one alkaline earth oxide (RO), wherein RO is selected from MgO, CaO, SrO, and / or BaO. Preferably, the glass contains at least BaO. Preferably, the glass contains BaO and at least one of MgO, CaO, and SrO. CaO and SrO lower the melting point and stabilize the glass against crystallization without reducing the chemical resistance to the same extent as alkali metal oxides.

[0041] Preferably, the total content of MgO, CaO, and SrO is in the range of 2.0 mol% to 25.0 mol%. In some advantageous embodiments, the glass contains a total content of MgO, CaO, and SrO in the range of 5.0 mol% to 22.0 mol%. In some advantageous embodiments, the total content of MgO, CaO, and SrO is in the range of 5.0 to 10.0 mol%. In some advantageous embodiments, the total content of MgO, CaO, and SrO is in the range of 12.0 mol% to 22.0 mol%.

[0042] In some advantageous embodiments, the glass contains BaO and at least one of MgO, CaO, and SrO, preferably MgO and / or CaO. Preferably, the glass has a total RO content, where RO = MgO, CaO, SrO, and / or BaO, of 5.0 mol% to 25.0 mol%, preferably of 8.0 mol% to 31.0 mol%, preferably of 10.0 mol% to 28.0 mol%, and preferably of 12.0 mol% to 24.0 mol%.

[0043] Preferably, the glass contains BaO. Advantageously, the glass contains more than 0 mol% to 17.0 mol%, more than 0 mol% to 15.0 mol%, preferably 1.0 mol% to 12 mol% or up to 13.0 mol%, and further preferably 2.0 mol% to 11.0 mol% or up to 13.0 mol% BaO.

[0044] In some advantageous embodiments, the glass contains MgO with a content of more than 0 mol% to 10.0 mol%, preferably from 0.5 mol% to 7.5 mol% or from 1.0 mol% to 6.0 mol%. Some advantageous variants contain MgO with a content of more than 0 mol% to 3.0 mol%, preferably from 1.0 mol% to 3.0 mol%. Some advantageous variants are free of MgO.

[0045] In advantageous embodiments, the glass contains CaO. The CaO content is preferably in the range of more than 0 mol% to 30.0 mol%, more preferably from 1.0 mol% to 25.0 mol%. In some advantageous embodiments, the glass contains 2.0 mol% to 22.0 mol%, more preferably from 3.0 mol% to 19.0 mol%, and also more preferably from 5.0 mol% to 15.0 mol% CaO. Some embodiments may be CaO-free.

[0046] The SrO content is preferably in the range of 0 mol% to 5.0 mol% or 4.0 mol%. In some advantageous embodiments, the SrO content is in the range of 0 mol% or 1.0 mol% to 3.0 mol%, preferably from 1.5 mol% to 2.5 mol%. Some advantageous embodiments are free of SrO.

[0047] Preferably, the glass contains a total RO + R₂O content in the range of 15.0 mol% to 40.0 mol%, more preferably 20.0 mol% to 35.0 mol%, and more preferably 23.0 mol% to 31.0 mol%. Glasses exhibiting the aforementioned total RO and R₂O content display favorable glass-forming properties. If the RO and R₂O content is too low, the glasses have an unfavorably high melting point; if the content is too high, the glasses exhibit an increased tendency to crystallize.

[0048] Optionally, the glass may contain ZnO. However, ZnO is hazardous to water and can corrode tanks and crucibles; therefore, the ZnO content is preferably limited to less than 10.0 mol%. In advantageous embodiments, the glass has a ZnO content of no more than 7.5 mol%, or no more than 5.5 mol%, and more preferably no more than 3.5 mol%. In some embodiments, the glass has a ZnO content of 0.5 mol% to 7.5 mol%, preferably 0.5 mol% to 5.5 mol%, and more preferably 0.75 mol% to 3.5 mol%. Some advantageous variants are ZnO-free.

[0049] Optionally, the glass may contain Ln₂O₃, where Ln₂O₃ = La₂O₃, Gd₂O₃, Y₂O₃, and / or Yb₂O₃. Generally, these components can be used to increase the refractive power of the glass; however, Ln₂O₃-containing glasses typically have a higher density. Therefore, the Ln₂O₃ content is limited to less than 5.0 mol%, preferably less than 2.0 mol%, more preferably less than 1.0 mol%, and most preferably less than 0.5 mol%. Preferably, the glass is free of Ln₂O₃.

[0050] The addition of conventional refining agents is not necessary, as the melt exhibits low viscosity at the temperatures required for melting. However, if refining agents such as As₂O₃, Sb₂O₃, SO₃, F, and / or Cl are added, their concentration can be significantly reduced, e.g., to < 0.1 mol%. Purely physical refining is also possible and advantageous. Optionally, the glass can contain one or more of the following refining components in the specified proportions in mol%: Sb2O3 0.0 to 1.0 As2O3 0.0 to 1.0 SO3 0.0 to 1.0 F 0.0 to 1.0 Cl 0.0 to 1.0

[0051] Sulfate (SO3) may be present in the glass in a small amount to help stabilize the higher oxidation states of polyvalent ions. If present, the amount is at least 0.01 mol%. Higher sulfate levels increase the risk of excessive bubble formation in the glass and the risk of platinum leaching into the glass. Therefore, the sulfate content is advantageously limited to a maximum of 0.5 mol%, preferably a maximum of 0.1 mol%, and most preferably a maximum of 0.05 mol%. Preferably, the glass is SO3-free.

[0052] In some embodiments, F can have a positive effect on the transmission of the glass by stabilizing higher oxidation states in polyvalent ions.

[0053] The glass may contain small amounts of hafnium (HfO2), preferably a maximum of 0.2 mol%, more preferably a maximum of 0.1 mol% or a maximum of 0.05 mol%. It is generally not actively added, but rather enters the glass along with the ZrO2 component via the raw material. When using a very pure ZrO2 raw material, the glass is advantageously HfO2-free.

[0054] In an advantageous embodiment, the glass has the following components in mol%: SiO2 10,0 - <30,0 preferably 12.0 - 28.0 B2O3 0 - 8,0 preferably 0 - 5.0 TiO2 + BaO 35,0 - 70,0 preferably 40.0 - 65.0 R2O + RO 15,0 - 40,0 preferably 20.0 - 35.0 ZnO < 10, 0 preferably ≤ 7.5 Ln2O3 < 2,0 preferably < 1.0

[0055] In an advantageous embodiment, the glass has the following components in mol%: SiO2 10,0 - <30,0 preferably 12.0 - 28.0 B2O3 0 - 8,0 preferably 0 - 5.0 TiO2 + BaO 35,0 - 70,0 preferably 40.0 - 65.0 R2O 1,0 - 20,0 preferably 2.0 - 17.0 RO 8,0 - 31,0 preferably 10.0 - 28.0 R2O + RO 15,0 - 40,0 preferably 20.0 - 35.0 ZnO ≤ 7,5 preferably ≤ 5.5 ZrO2 0,5 - 7,5 preferably 1.5 - 6.5 Ln2O3 < 1,0 preferably 0

[0056] In an advantageous embodiment, the glass has the following components in mol%: SiO2 12,0 - 28,0 preferably 13.0 - 25.0 B2O3 0 - 5,0 preferably 0 - 4.0 TiO2 + BaO 40,0 - 65,0 preferably 45.0 - 63.0 TiO2 35,0 - 65,0 preferably 40.0 - 61.0 R2O 2,0 - 17,0 preferably 3.0 - 15.0 Li2O 0 - 10,0 preferably 0 - 7.0 Na2O 0,5 -15,0 preferably 1.0 - 13.5 K2O 0 - 5,0 preferably 0 - 3.0 RO 10,0 - 28,0 preferably 12.0 - 24.0 MgO 0 - 10,0 preferably 0 - 7.5 CaO 1,0 - 25,0 preferably 2.0 - 22.0 SrO 0 - 5,0 preferably 0 -3.0 BaO 1,0 - 12,0 preferably 2.0 - 11.0 R2O + RO 20,0 - 35,0 preferably 23.0 - 31.0 ZnO 0- 5,5 preferably 0 - 3.5 ZrO2 1,5 - 6,5 preferably 2.5 - 5.5 Ln2O3 < 1,0 preferably 0

[0057] In an advantageous embodiment, the glass has the following components in mol%: SiO2 15,0 - <30, 0 B2O3 0 - 5,0 TiO2 + BaO 40,0 - 65,0 R2O 1,0 - 20,0 RO 8,0 - 28,0 R2O + RO 20,0 - 35,0 ZnO ≤ 3,5 ZrO2 0,5 - 7,5 Ln2O3 < 1,0

[0058] In an advantageous embodiment, the glass has the following components in mol%: SiO2 10,0 - 20,0 B2O3 0 - 5,0 TiO2 + BaO 45,0 - 60,0 R2O < 1.0, preferably 0 RO 25,0 - 40,0 R2O + RO 25,0 - 40,0 ZnO ≤ 3.5, preferably ≤ 2.5 ZrO2 2,5 - 7,5 Ln2O3 < 1,0

[0059] In an advantageous embodiment, the glass consists of at least 95.0 mol%, in particular at least 98.0 mol% or at least 99.0 mol%, of the components described herein, in particular the components listed in the preceding tables. In one embodiment, the glass consists substantially entirely of these components.

[0060] Preferably, the glass is essentially free of bismuth (Bi₂O₃) and / or lead (PbO). Adding bismuth would disproportionately increase the glass's density. Furthermore, bismuth ions are reduced to elemental bismuth even at relatively low temperatures around 1000°C, resulting in a strong gray tint to the glass. PbO is also omitted due to its negative impact on density. Moreover, it is a toxic component.

[0061] Due to the high levels of niobium and titanium, expensive components such as tantalum (Ta2O5) and / or tungsten (WO3) and / or germanium (GeO2) are not needed in the glass, or only in small amounts, to obtain a glass with the desired high refractive index.

[0062] Preferably, the glass is free of phosphate (P₂O₅) because phosphate makes the melt significantly reducing and, through the reduction of TiO₂ and / or Nb₂O₅, lowers the transmission. Furthermore, a reducing melt can corrode platinum, which increases the input of platinum into the melt and leads to discoloration or increased scattering of the glass.

[0063] Optionally, the glass—with respect to the respective cations—is essentially free of one or more components selected from cadmium, gallium, germanium, thallium, coloring components—such as cobalt, vanadium, chromium, molybdenum, copper, nickel—and combinations thereof. Components such as iron, cerium, manganese, selenium, and / or tellurium may be present in the glass in small amounts, for example, as impurities. Iron, cerium, selenium, and tellurium, in particular, but also manganese, can act as redox partners. However, it is advantageous that these components, either individually or in combination, are not intentionally added to the glass.

[0064] When this description states that the glass is free of a component or does not contain a certain component, this means that this component may only be present in the glass as an impurity. This means that it is not added in significant quantities. According to the invention, non-significant quantities are amounts of less than 100 ppm, preferably less than 50 ppm, and most preferably less than 10 ppm (w / w).

[0065] Preferably the optical glass has a pure transmission (t i (10 mm, 460 nm)) of at least 80%, preferably at least 85%, more preferably at least 90% and particularly preferably at least 93%, measured at a wavelength of 460 nm and a sample thickness of 10 mm.

[0066] The pure transmission or degree of pure transmission can be measured using methods familiar to those skilled in the art, for example according to DIN 5036-1:1978. In this description, the pure transmission values ​​refer to a wavelength of 460 nm and a sample thickness of 10 mm. The specification of a "sample thickness" does not mean that the glass has this thickness, but merely indicates the thickness to which the pure transmission value refers.

[0067] Unless otherwise specified or it is obvious to a person skilled in the art, the measurements described herein are carried out at 20°C and 101.3 kPa atmospheric pressure.

[0068] In one aspect, the invention relates to a glass article that incorporates or consists of the glass according to the invention. The glass article can have different shapes. Optionally, the article has the following shape: - a glass substrate, in particular as part of a stack of substrates, for a component of an optic, in particular in AR glasses, - a wafer, in particular with a maximum diameter of 5.0 cm to 50.0 cm or with a diameter between 0.7 cm and 50 cm, preferably between 3 cm and 45 cm, or between 5 cm and 40 cm, - a lens, in particular a spherical lens, a rod lens, a prism or an aspheric lens, and / or - of an optical waveguide, in particular a fiber or plate.

[0069] In another aspect, the glass article according to the invention is a chemically tempered glass article, in particular a chemically tempered glass substrate, a chemically tempered wafer and / or a chemically tempered lens. It will be understood by those skilled in the art that these are glass articles comprising the optical glasses according to the invention, which are chemically temperable.

[0070] For the purposes of this disclosure, a chemically hardenable glass is understood to be a glass that is amenable to an ion exchange process. In such a process, alkali metal ions are exchanged in a surface layer of a glass article, such as a wafer. This occurs by creating a stress zone in the surface layer, which is achieved by exchanging ions with smaller radii for ions with larger radii. For this purpose, the glass article is immersed in an ion exchange bath, for example, a molten salt solution. The ion exchange bath contains the ions with larger ionic radii, in particular potassium and / or sodium ions, causing them to migrate into the surface layer of the glass article. In exchange, ions with smaller ionic radii, in particular lithium and / or sodium ions, migrate from the surface layer of the glass article into the ion exchange bath.

[0071] This results in the formation of a compressive stress zone. This zone can be described by the characteristic parameters of the compressive stress, also referred to as "compressive stress" or abbreviated "CS", and the compressive stress depth, also referred to as "depth of layer" or abbreviated "DoL". This compressive stress depth DoL is well known to those skilled in the art and, within the scope of this disclosure, denotes the depth at which the stress curve crosses zero.

[0072] Higher mechanical strengths can be achieved with chemically hardened glass articles of this kind.

[0073] Preferably, the production of the chemically tempered glass article comprises the following steps: a) Providing the glass item described above, b) Performing at least one initial ion exchange, c) Optionally, a second ion exchange can be performed.

[0074] Preferably, the first ion exchange takes place for a duration of 0.5 to 24 hours, preferably from 1 to 5 hours, more preferably from 2 to 8 hours, at a temperature of 350°C to 500°C, preferably from 370°C to 450°C, particularly preferably from 380°C to 430°C, wherein the exchange bath contains at least one potassium salt, in particular KNO3 and / or at least one sodium salt, in particular NaNO3.

[0075] In some advantageous embodiments, a second ion exchange then takes place for a duration of 0.5 to 24 hours, preferably 1 to 5 hours, more preferably 2 to 8 hours, at a temperature of 350°C and 500°C, preferably 370°C to 450°C, particularly preferably 380°C to 430°C, wherein the exchange bath contains at least one potassium salt, in particular KNO3 and / or at least one sodium salt, in particular NaNO3.

[0076] In another aspect, the invention relates to the use of a glass or glass article described herein in AR glasses, meta-optics, wafer-level optics, optical wafer applications, or classical optics. Alternatively or additionally, the glass or glass article described herein can be used as a wafer, lens, or optical waveguide.

[0077] The glasses according to the invention can be melted from commercially available raw materials. For example, it is possible to melt the glasses in a device as described in DE 10 2020 120168 A1. Examples:

[0078] The compositions shown in Tables 1 to 4 below were melted and their properties were examined.

[0079] Composition and properties: Table 1: mol % 1 2 3 4 5 6 7 B2O3 2,90 2,90 0,00 2,90 1,00 0,00 0,00 BaO 9,37 7,03 7,82 8,49 0,00 7,82 7,38 TiO2 47,67 47,67 50,92 47,49 47,87 50,92 50,83 Nb2O5 0,00 0,00 0,00 0,00 0,00 0,00 0,00 SiO2 17,40 17,40 17,88 17,41 18,04 17,88 17,88 Al2O3 0,00 0,00 0,00 0,00 0,00 0,00 0,00 MgO 0,00 0,00 0,00 0,00 4,20 0,00 0,00 CaO 14,05 16,39 7,82 14,15 15,92 7,82 7,38 Li2O 0,00 0,00 1,17 0,00 0,00 0,00 0,00 Na2O 3,51 4,52 8,21 4, 55 6,63 10,56 10,59 K2O 1,51 0,50 2,35 0,51 0,74 1,17 1,18 ZnO 0,00 0,00 0,00 0,94 0, 88 0,00 0,94 SrO 0,00 0,00 0,00 0,00 1,11 0,00 0,00 As2O3 0,00 0,00 0,00 0,00 0,00 0,00 0,00 Y2O3 0,00 0,00 0,00 0,00 0,00 0, 00 0,00 Sb2O3 0,00 0,00 0,00 0,00 0,00 0, 00 0,00 La2O3 0,00 0,00 0,00 0,00 0,00 0, 00 0,00 Gd2O3 0,00 0,00 0,00 0,00 0,00 0, 00 0, 00 ZrO2 3,59 3,59 3, 83 3,57 3,60 3, 83 3, 83 sum 100,00 100,00 100,00 100, 00 100, 00 100, 00 100, 00 Characteristics n d 1,994 1,993 1,989 1,994 1,988 1,988 1,989 n d 20,5 20,8 20,1 20,6 20,6 20,2 20,1 Density [g / cm³] 3 ] 3,73 3,67 3,65 3,73 3,47 3,66 3,65 Table 2: mol% 8 9 10 11 12 13 14 B2O3 0,00 0,94 1,05 1,04 0,00 0,00 0,00 BaO 7,38 7,42 8,46 8, 46 8, 47 7,38 8,36 TiO2 50,28 50, 76 48,25 48,45 50,28 50,28 48, 97 Nb2O5 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 SiO2 17,88 16, 85 18,87 18,68 17,88 17,88 18,91 Al2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 MgO 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 CaO 7,38 7,42 11,84 11,84 6, 28 6,28 9,29 Li2O 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 Na2O 10,59 10,66 7,05 6,48 10,59 10,59 8,45 K2O 1,18 1,18 0,00 0,56 1,18 1, 18 0,84 ZnO 0,94 0,95 0,85 0,85 0,94 0,94 0,93 SrO 0,00 0,00 0,00 0, 00 0, 00 1, 10 0,00 As2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 Y2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 Sb2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 La2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 Gd2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 ZrO2 4,37 3, 82 3,63 3, 65 4, 37 4,37 4,26 sum 100,00 100,00 100,00 100, 00 100, 00 100, 00 100,00 Characteristics n d 1,987 1,988 1,992 1,992 1,987 1,982 1,991 n d 20,3 20,2 20,8 20,6 20,5 20,4 21,0 Density [g / cm³] 3 ] 3,66 3,65 3,72 3, 72 3, 68 3,67 3,70 Table 3: mol% 15 16 17 18 19 20 21 B2O3 0,00 0,00 0,00 0, 00 0,00 0,00 0,00 BaO 8,47 8,52 8,31 8,36 4,42 8,31 3,38 TiO2 49,87 50,11 48,39 48,87 45,46 49,03 48,73 Nb2O5 0,00 0,00 0,00 0,00 0,00 0,00 0,00 SiO2 18,33 18,16 20,17 19,02 19,53 18,39 19,47 Al2O3 0,00 0,00 0,00 0,00 0,00 0,00 0,00 MgO 0,00 0,00 0,00 0,00 5,85 0,00 1,31 CaO 6,28 5,84 11,37 9,29 14,57 9,44 12,94 Li2O 0,59 0,00 0,00 0,46 0,00 0, 00 0,00 Na2O 10,24 10,89 7,02 7,99 5,57 8,78 8,82 K2O 0,94 0,95 0,00 0,84 0,00 0,66 0,56 ZnO 0,94 0,95 0,84 0,93 1,17 1,13 1,13 SrO 0,00 0,00 0,00 0,00 0,00 0,00 0,00 As2O3 0,00 0,00 0,00 0,00 0,00 0,00 0,00 Y2O3 0,00 0,24 0,00 0,00 0,00 0,00 0,00 Sb2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 La2O3 0,00 0,00 0,26 0, 00 0, 00 0, 00 0,00 Gd2O3 0,00 0,00 0,00 0,00 0,00 0,00 0,00 ZrO2 4,34 4,36 3,64 4,25 3,42 4,26 3,67 sum 100,00 100,00 100,00 100,00 100,00 100,00 100,00 Characteristics n d 1,987 1,979 1,985 1,991 1,990 1,991 1,986 n d 20,8 20,3 20,4 20,6 21,2 21 20,4 Density [g / cm³] 3 ] 3,69 3,67 3,69 3,71 3,61 3,71 3,54 Table 4: mol % 22 23 24 25 26 27 28 B2O3 0,00 0,00 0,00 0, 00 0, 00 1, 57 0,00 BaO 3,39 3,41 3,41 2,08 0, 00 8,30 7,35 TiO2 48, 68 47,32 46,62 48,65 48,50 49,25 46,64 Nb2O5 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 SiO2 18,39 20, 67 21,42 19,37 19,17 17,74 21,61 Al2O3 1,02 0,00 0,00 0, 00 0, 00 0, 00 0,69 MgO 1,32 1, 92 1, 92 1,32 1, 34 0, 00 0,00 CaO 12, 99 14,72 14,72 13,03 13,57 9, 44 5, 94 Li2O 0,00 0,00 5,69 0, 00 0, 00 0, 00 0,53 Na2O 8, 85 7,11 1,42 8, 97 9, 08 8,77 12,61 K2O 0,56 0,00 0,00 0, 47 0,48 0,66 0,00 ZnO 1,13 1,28 1,28 2, 45 4,21 1,13 0,85 SrO 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 As2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 Y2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 Sb2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 La2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 Gd2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 ZrO2 3,66 3,56 3,51 3,66 3,65 3,14 3,78 sum 100,00 100,00 100,00 100, 00 100, 00 100, 0 100,00 Characteristics n d 1,986 1,988 2,004 1,983 1,990 1, 987 1,950 n d 20, 4 20, 7 20, 5 20,3 20,1 20,2 21, 0 Density [g / cm³] 3 ] 3,56 3,56 3,60 3,53 3, 49 3,69 3,60 Table 5: mol% 29 30 31 32 33 34 35 B2O3 0,00 0,00 3,50 6, 84 0, 00 0, 00 0,00 BaO 6, 98 8, 48 8,05 14,53 8,48 7,89 0,00 TiO2 45,44 45,49 44, 99 39,49 45,44 46,68 43,88 Nb2O5 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 SiO2 19, 74 24,05 16,34 13,68 23,83 22,75 26,76 Al2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 MgO 4,14 0,00 3,63 4,00 0, 00 0, 00 0,69 CaO 13,19 5,60 12,98 16,35 5,76 4, 90 6,95 Li2O 0,00 0,45 0,00 0, 00 0, 00 0, 00 0,69 Na2O 5,21 10,11 5,23 0, 00 10,56 11,74 15,29 K2O 0,33 0, 80 0,33 0, 00 0, 80 0, 88 1,39 ZnO 1,55 1,06 1,30 1, 45 0, 91 0, 82 1,04 SrO 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 As2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 Y2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 Sb2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 La2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 Gd2O3 0,00 0,00 0,00 0, 00 0, 00 0, 00 0,00 ZrO2 3,42 3,96 3,65 3,67 4,22 4,34 3,30 sum 100,00 100,00 100,00 100, 00 100, 00 100, 00 100,00 Characteristics n d 1,988 1, 942 1,983 1, 965 1, 943 1,946 1, 90 V d 20, 7 20, 3 20, 8 23 22,3 20, 9 22,6 Density [g / cm³] 3 ] 3,71 3,61 3,71 3, 93 3,61 3, 58 3,24 Table 6 mol% 36 37 38 39 40 41 42 B2O3 1,14 0,00 3,75 4,61 0,00 0,00 4,93 BaO 8,02 1,14 13,66 14,59 7,91 7,43 16,29 TiO2 46,63 43,83 44,47 42,61 46,39 46,41 41,34 Nb2O5 0,00 0,00 0,00 0,00 0,00 0,00 0, 00 SiO2 20,44 24,05 17,48 17,14 21,42 23,17 11,94 Al2O3 0,00 0,00 0,00 0,00 0,00 0,00 4,03 MgO 0,00 0,00 0,00 0,97 0,54 0,51 1,04 CaO 13,37 7,43 13,94 15,89 8,63 8, 10 16,29 Li2O 0,00 0,95 0,00 0,00 0,00 0,00 0, 00 Na2O 6,00 17,14 2,51 0,00 10,99 10,31 0, 00 K2O 0,00 0,95 0,00 0,00 0,00 0,00 0,00 ZnO 0,89 0,95 0,85 0,97 0, 90 0,84 0,00 SrO 0,00 0,00 0,00 0,00 0,00 0,00 1,04 As2O3 0,00 0,00 0,00 0,00 0,00 0,00 0, 00 Y2O3 0,00 0,00 0,00 0,00 0,00 0,00 0, 00 Sb2O3 0,00 0,00 0,00 0,00 0,00 0,00 0, 00 La2O3 0,00 0,00 0,00 0,00 0,00 0,00 0,00 Gd2O3 0,00 0,00 0,00 0,00 0,00 0,00 0,00 ZrO2 3,51 3,55 3,35 3,21 3,22 3,23 3,11 sum 100,00 100,00 100,00 100,00 100,00 100,00 100,00 Characteristics n d 1,994 1,897 1,981 1,984 1,953 1,963 1,980 n d 20,9 21,6 21,8 21,9 21,3 20,7 21,8 Density [g / cm³] 3 ] 3,71 3,28 3,89 3,93 3,62 3,58 4,02

[0080] The glasses of the examples according to the invention have a low density with a high refractive index and a favorable product of Abbe number and density and exhibit a low T max It was found within the scope of the invention that the glasses according to the invention exhibit a low tendency to crystallize.

[0081] Although the present invention has been described using preferred embodiments, it is not limited to these, but can be modified in many ways. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2020 120168 A1

[0077]

Claims

[1] Optical glass with a refractive index n d of more than 1.85, a quotient of d of less than 35 and a temperature T max of not more than 1350°C, comprising at least SiO2 and TiO2, comprising less than 30.0 mol% SiO2, less than 2.0 mol% Nb2O5, less than 17 mol% BaO and less than 5.0 mol% Ln2O3, where Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3. [2] Optical glass according to claim 1, wherein the glass has a molar ratio (TiO2+ZrO2+2*Nb2O5+2*Ta2O5+2*Al2O3+SiO2+B2O3) / (R2O+RO+2*Ln2O3) of 1.5-3.5, wherein R2O = Li2O, Na2O and / or K2O and RO = MgO, CaO, SrO and / or BaO and Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3. [3] Optical glass according to claim 1 or 2, wherein the glass is a product of Abbezahl v d and density r of less than 120 g / cm³ 3 preferably less than 100 g / cm² 3 especially preferred less than 90 g / cm³ 3 and preferably more than 50 g / cm² 3, preferably more than 55 g / cm² 3 , especially preferred more than 60 g / cm² 3 exhibits. [4] Optical glass according to any of the preceding claims, wherein the glass is substantially free of Nb2O5. [5] Optical glass according to any of the preceding claims, wherein the glass contains more than 0 mol% to 15.0 mol%, preferably 2.0 mol% to 13.0 mol% BaO. [6] Optical glass according to any one of the preceding claims, wherein the glass has a total BaO and TiO2 content of at least 35.0 mol%, preferably at least 40.0 mol%, preferably at least 45.0 mol% and / or not more than 70.0 mol%, preferably not more than 65.0 mol%. [7] Optical glass according to any of the preceding claims, wherein the glass has a total R2O content, where R2O = Li2O, Na2O and / or K2O, of 1.0 mol% to 20.0 mol%, preferably 2.0 mol% to 17 mol%, particularly preferably 3.0 mol% to 15.0 mol%. [8] Optical glass according to any of the preceding claims, wherein the glass has a total RO content, where RO = MgO, CaO, SrO and / or BaO, of 8.0 mol% to 31.0 mol%, preferably 10.0 mol% to 28.0 mol% and / or a total MgO, CaO and SrO content of 2.0 mol% to 25.0 mol%, preferably 5.0 mol% to 22.0 mol%. [9] Optical glass according to any of the preceding claims, wherein the glass has a total RO + R2O content of 15.0 mol% to 40.0 mol%, preferably of 20.0 mol% to 35.0 mol%, particularly preferably of 23.0 to 31.0 mol%. [10] Optical glass according to any one of the preceding claims, wherein the glass contains 0.5 mol% to 7.5 mol%, preferably 1.5 mol% to 6.5 mol%, more preferably 2.5 mol% to 5.5 mol% ZrO2. [11] Optical glass according to any of the preceding claims, wherein the glass has less than 10.0 mol%, preferably not more than 7.5 mol% ZnO, particularly preferably from 0.5 mol% to 5.5 mol%. [12] Optical glass according to any one of the preceding claims, wherein the glass comprises the following components in mol%: SiO2 10,0 - < 30,0 preferably 12.0 - 28.0 B2O3 0 - 8,0 preferably 0 - 5.0 TiO2 + BaO 35,0 - 70,0 preferably 40.0 - 65.0 R2O + RO 15,0 - 40,0 preferably 20.0 - 35.0 ZnO < 10, 0 preferably ≤ 7.5 Ln2O3 < 2,0 preferably < 1.0 [13] Optical glass according to any of the preceding claims, wherein the glass has a total SiO2 and B2O3 content of 12.0 mol% to 25.0 mol%, preferably of 15.0 mol% to 23.0 mol%. [14] Optical glass according to any of the preceding claims, wherein the glass contains less than 5.0 mol%, preferably less than 3.0 mol% K2O. [15] Optical glass according to any one of the preceding claims, wherein the glass comprises the following components in mol%: SiO2 10,0 - <30, 0 preferably 12.0 - 28.0 B2O3 0 - 8,0 preferably 0 - 5.0 TiO2 + BaO 35,0 - 70,0 preferably 40.0 - 65.0 R2O 1,0 - 20,0 preferably 2.0 - 17.0 RO 8,0 - 31,0 preferably 10.0 - 28.0 R2O + RO 15,0 - 40,0 preferably 20.0 - 35.0 ZnO ≤ 7,5 preferably ≤ 5.5 ZrO2 0,5 - 7,5 preferably 1.5 - 6.5 Ln2O3 < 1,0 preferably 0 [16] Optical glass according to any one of the preceding claims, wherein the glass comprises the following components in mol%: SiO2 12,0 - 28,0 preferably 13.0 - 25.0 B2O3 0 - 5,0 preferably 0 - 4.0 TiO2 + BaO 40,0 - 65,0 preferably 45.0 - 63.0 TiO2 35,0 - 65,0 preferably 40.0 - 61.0 R2O 2,0 - 17,0 preferably 3.0 - 15.0 Li2O 0 - 10,0 preferably 0 - 7.0 Na2O 0,5 -15,0 preferably 1.0 - 13.5 K2O 0 - 5,0 preferably 0 - 3.0 RO 10,0 - 28,0 preferably 12.0 - 24.0 MgO 0 - 10,0 preferably 0 - 7.5 CaO 1,0 - 25,0 preferably 2.0 - 22.0 SrO 0 - 5,0 preferably 0 - 3.0 BaO 1,0 - 12,0 preferably 2.0 - 11.0 R2O + RO 20,0 - 35,0 preferably 23.0 - 31.0 ZnO 0 - 5,5 preferably 0 - 3.5 ZrO2 1,5 - 6,5 preferably 2.5 - 5.5 Ln2O3 < 1,0 preferably 0 [17] Optical glass according to any of the preceding claims, wherein the glass has a pure transmission of at least 80%, preferably at least 85%, more preferably at least 90% and particularly preferably at least 93%, measured at a wavelength of 460 nm and a sample thickness of 10 mm. [18] Glass articles comprising an optical glass according to at least one of the preceding claims, in the form - a glass substrate, in particular as part of a stack of substrates, for a component of an optic, in particular in AR glasses, - a wafer, in particular with a maximum diameter of 5.0 cm to 50.0 cm or with a diameter between 0.7 cm and 50 cm, preferably between 3 cm and 45 cm or between 5 cm and 40 cm, - a lens, in particular a spherical lens, a rod lens, a prism or an aspheric lens, and / or - of an optical waveguide, in particular a fiber or plate. [19] Use of an optical glass or glass article according to at least one of the preceding claims in AR glasses, meta-optics, wafer-level optics, optical wafer applications, or classical optics; and / or as a wafer, lens or optical waveguide.