High-index, low-density glass

Abstract

The invention relates to an optical glass having a refractive index of more than 1.95, to glass articles comprising the optical glass and to the use thereof, in particular in the fields of optics and lenses, metaoptics and in augmented reality (AR).

Description

[0001] The invention relates to an optical glass having a refractive index of more than 1.95, to glass articles comprising the optical glass and to the use thereof, in particular in the fields of optics and lenses, metaoptics and in augmented reality (AR).

[0002] The invention relates to lenses that can be used in the field of augmented reality (AR). High-refractive index lenses—i.e., lenses with a high refractive index—are advantageous for AR glasses 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 lens would be significantly heavier, making AR glasses uncomfortable to wear for extended periods. Since the trend is moving away from headsets toward standard glasses that are then intended to be worn for longer periods or always, like normal glasses, it is necessary to make the glasses lighter.This weight reduction is also advantageous for many other applications, since camera lenses in the digital single lens reflex (DSLR) range are often either very bulky or very heavy, which also significantly increases the battery power requirements of the autofocus.

[0003] Some of the state-of-the-art glasses come from the niobium phosphate or titanium phosphate system, meaning they contain significant amounts of P2O5 and niobium or titanium. Some of these glasses are very problematic to produce because oxygen loss, e.g. due to excessively high melting and refining temperatures in the already reducing phosphate system, leads to lower oxidation states. For niobium, for example, this is an oxidation state of below V, and for titanium below IV. This can lead to an intense brown or even black coloration in the niobium system, or to a blue, yellow-green, brown or even black coloration in the titanium system. In addition, titanium significantly increases the tendency to crystallize, which is a known problem in the heavy flint sector with existing higher refractive index glasses, which then, for example, are no longer repressible.In contrast to 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 tinge of barium titanium silicates.

[0004] Furthermore, the niobium phosphate glass family—like the high-index heavy flint or lanthanum heavy flint family—is not only prone to interfacial crystallization but also exhibits very rapid crystal growth, making post-cooling (stress cooling or index adjustment) critical for pre-nucleated glasses. Furthermore, the glass is known to be relatively brittle and therefore difficult to polish into very thin wafers.

[0005] On the other hand, climate resistance, at least for the 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 families are well known in the literature.

[0006] The lanthanum flint systems available on the market, which are in a refractive index range that is interesting for AR applications, have a significantly less favorable combination of refractive index n dand density. The comparatively high density and the higher Abbe number of these glasses are caused in particular by high contents of lanthanum oxide. Furthermore, such glasses have a relatively high hardness, which drives up the costs of wafer production due to the long grinding times. In some cases, the raw glass costs are also significantly higher, as these raw materials from the rare earth range, tungsten oxide, tantalum oxide and other expensive raw materials are used in the production of these. In the area of ​​heavy flint, Nb2O5 is often the batch cost driver, while the other raw materials, even in optical quality, are relatively inexpensive in comparison. Furthermore, the available lanthanum heavy flint glasses are usually free of alkali oxides and therefore cannot be chemically strengthened. Depending on the application, however, it can be advantageous to ensure the mechanical stability of potentially increasingly thin optical components (e.g.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, due to their high Bi2O3 content, are also very soft (scratch-sensitive). They also exhibit a disadvantageous UV transmission edge, for example, an insufficiently steep UV edge and / or a UV edge shifted to the longer-wavelength range of the spectrum. P-SF glasses, in particular, are also produced discontinuously in platinum crucibles and could lead to problems with platinum alloying and the reduction of Bi(III) to Bi(0) in a tank.

[0008] As mentioned above, there are some more or less suitable glasses, which usually have too low refractive indices (typical heavy flint glasses) or are difficult to process or work (typical lanthanum heavy flint glasses).

[0009] It is an object of this invention to provide glasses having a high refractive index n d and have the lowest possible density. The glass should exhibit the highest possible internal transmission, be easy to hot-form, and be easy to process. To achieve this, the hardness must be neither too low (which would result in more scratches and microcracks) nor too high (which would result in long grinding times and thus microcracks). The glass should exhibit high chemical resistance.

[0010] In one aspect, the invention relates to an optical glass having a refractive index n d of more than 1.95 and preferably not more than 2.05, an Abbe number of d of less than 32 and a temperature T maxof not more than 1350°C, comprising at least SiO2, TiO2 and Nb2O5, comprising less than 30.0 mol% SiO2, less than 5.0 mol% ZnO and less than 5.0 mol% Ln2O3, where Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3, wherein the glass satisfies at least one of the following conditions: (i) a K2O content of more than 0 mol%, (ii) a B2O3 content of not more than 0.5 mol% (iii) a molar ratio of B2O3 to SiO2 of at least 0.09.

[0011] In an advantageous embodiment, the invention relates to an optical glass with a refractive index n d of more than 1.95 and preferably not more than 2.05, an Abbe number of d of less than 32 and a temperature T maxof not more than 1350°C, comprising at least SiO2, TiO2 and Nb2O5, comprising less than 30.0 mol% SiO2, less than 5.0 mol% ZnO and less than 5.0 mol% Ln2O3, where Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3 and has a K2O content of more than 0 mol%.

[0012] In an advantageous embodiment, the invention relates to an optical glass with a refractive index n d of more than 1.95 and preferably not more than 2.05, an Abbe number of d of less than 32 and a temperature T max of not more than 1350°C, which comprises at least SiO2, TiO2 and Nb2O3, comprising less than 30.0 mol% SiO2, less than 5.0 mol% ZnO and less than 5.0 mol% Ln2O3, where Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3, and has a K2O content of more than 0 mol% and a B2O3 content of not more than 0.5 mol%, preferably free of B2O3.

[0013] In an advantageous embodiment, the invention relates to an optical glass with a refractive index n d of more than 1.95 and preferably not more than 2.05, an Abbe number of d of less than 32 and a temperature T max of not more than 1350°C, comprising at least SiO2, TiO2 and Nb2O5, comprising less than 30.0 mol% SiO2, less than 5.0 mol% ZnO and less than 5.0 mol% Ln2O3, where Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3, wherein the glass has a K2O content of more than 0 mol% and a molar ratio of B2O3 to SiO2 of at least 0.09.

[0014] In an advantageous embodiment, the invention relates to an optical glass with a refractive index n d of more than 1.95 and preferably not more than 2.05, an Abbe number of d of less than 32 and a temperature T maxof not more than 1350°C, comprising at least SiO2, TiO2 and Nb2O5, comprising less than 30.0 mol% SiO2, less than 5.0 mol% ZnO and less than 5.0 mol% Ln2O3, where Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3, wherein the glass has a B2O3 content of not more than 0.5 mol%, preferably is free of B2O3.

[0015] In an advantageous embodiment, the invention relates to an optical glass with a refractive index n d of more than 1.95 and preferably not more than 2.05, an Abbe number of d of less than 32 and a temperature T max of not more than 1350°C, comprising at least SiO2, TiO2 and Nb2O5, comprising less than 30.0 mol% SiO2, less than 5.0 mol% ZnO and less than 5.0 mol% Ln2O3, where Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3, wherein the glass has a molar ratio of B2O3 to SiO2 of at least 0.09.

[0016] Within the scope of the invention, a TiO2- and Nb2O5-containing glass system with SiO2 was discovered, which, compared to the glasses described above from the niobium phosphate or titanium phosphate system, is more stable in terms of achievable internal transmission, has a higher refractive index, and yet a relatively low density. Furthermore, the glass system exhibits a higher hardness than the described niobium phosphate glasses.

[0017] The optical glass according to the invention has a refractive index n d of more than 1.95 and preferably not more than 2.05.

[0018] In advantageous embodiments, the refractive index n is d more than 1,950, preferably at least 1,955, 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 dThe upper limit can be 2.05 or 2.050 or 2.045 or 2.040 or 2.035 or 2.030 or 2.025 or 2.020. Overall, the refractive index is therefore advantageously in a range of more than 1.95 to 2.05. The refractive index n d is known to the person skilled in the art and refers in particular to the refractive index at a wavelength of approximately 587.6 nm (wavelength of the d-line of helium). The person skilled in the art knows how the refractive index n d can be determined.

[0019] The refractive index is preferably determined using a refractometer, in particular a V-block refractometer. Samples with a square or nearly square base (e.g., with dimensions of approximately 20 mm × 20 mm × 5 mm) can be used. When measuring with a V-block refractometer, the samples are usually 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, allowing the refractive index of the sample to be determined. The measurement is preferably carried out at a temperature of 22°C.

[0020] According to the invention, the glass has an Abbe number, ie dispersion (v d), of less than 32. In advantageous embodiments, the dispersion is less than 30 or less than 25, preferably less than 24 or less than 23 and / or more than 18, preferably more than 18.5, more preferably more than 19.0, more preferably more than 19.5 and / or more than 20. The dispersion v d is calculated in a known way by determining the refractive indices n d (at about 587.6 nm), n F (at about 486 nm) and n c (at about 656 nm) can be determined with a refractometer and put into relation to each other: vd=(nd−1) / (nF−nC).

[0021] In addition, the glass according to the invention has a temperature T max of ≤ 1350°C. T maxis a composition-dependent glass parameter and indicates the minimum temperature required in the melting process to produce a "bright" melt from the starting materials (e.g. raw materials, cullet, etc.). A "bright" melt is present when there are no melt relics - for example, incompletely melted raw materials - and no crystals in the melt. As explained at the beginning, the melting and refining temperatures should be as low as possible to prevent the ingress of refractory material into the glass and the coloring of the glass by polyvalent ions in a low oxidation state. This allows for high pure transmission. Since the melting and refining temperatures cannot be selected as high as desired due to the requirement to achieve the highest possible pure transmission, the melting temperature has an upper limit, which is why the temperature point described here is also referred to as "T max “ Tmax is therefore the lowest temperature at which a bright, crystal-free melt can be produced. Due to this relationship, T max a good measure of the liquidus temperature of the glass (see below).

[0022] In the context of the invention, T max The composition of a glass is systematically determined on a laboratory scale in series of experiments by melting the same glass from the starting components in small crucibles, each with a volume of 20 ml, at different maximum temperatures, with temperature increments of 10°C. Starting with the lowest temperature and continuing to the highest temperature, the melting result is then visually evaluated to determine whether a bright melt has already formed or whether relics and / or crystals are still present in the glass.

[0023] The T determined in this way for a composition max-value could also be reproduced with laboratory melts in a larger volume (e.g. 1 liter). Furthermore, further experiments have shown that the temperature point T max is 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, is max is a good measure for the liquidus temperature of the glass, which is not exactly determined here.

[0024] In an advantageous development of the invention, T 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 not more than 1290°C or not more than 1280°C.

[0025] 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 T g can be advantageous in terms of crystallization stability, as it reduces the temperature difference to T max is lower and the glass reaches a stable glassy state more quickly. However, the glasses are still easy to hot-form and process.

[0026] 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, where R2O = Li2O, Na2O and / or K2O and RO = MgO, CaO, SrO and / or BaO and Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3. With regard to the ratio of the components TiO2, ZrO2, Nb2O3, Ta2O3, Al2O3, SiO2, and B2O3 to the components R2O, RO, and Ln2O3, it is important to note that the proportions must be selected such that the inventive condition (TiO2+ZrO2+2*Nb2O5+2*Ta2O5+2*Al2O3+SiO2+B2O3) / (RO+RO+2*Ln2O3) of 1.5-3.5 is met. Higher ratios pose the risk of undesirable crystallization and / or undesirable discoloration of the glasses. A ratio that is too low also poses 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.

[0027] 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, where R2O = Li2O, Na2O and / or K2O and RO = MgO, CaO, SrO and / or BaO and Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3. With regard to the ratio of the components TiO2, ZrO2, Nb2O5, Ta2O5, Al2O3, SiO2, and B2O3 to the components R2O, Cs2O, RO, and Ln2O3, it is important to note that the proportions must be selected such that the inventive condition (TiO2+ZrO2+2*Nb2O5+2*Ta2O5+2*Al2O3+SiO2+B2O3) / (RO+Cs2O+RO+2*Ln2O3) of 1.5-3.5 is met. Higher ratios pose the risk of undesirable crystallization and / or desired discoloration of the glasses. A ratio that is too low also poses 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.

[0028] Preferably, the optical glass according to the invention has a density ρ of not more than 4.5 g / cm 3 , preferably not more than 4.3 g / cm 3 , preferably not more than 4.1 g / cm 3 , more preferably not more than 4.0 g / cm 3 Preferably, the density of the glass according to the invention is 3.0 g / cm 3 up to 4.5 g / cm 3 , preferably 3.2 g / cm 3 up to 4.3 g / cm 3 , preferably 3.5 g / cm 3 up to 4.1 g / cm 3 , particularly preferably 3.6 g / cm 3 up to 4.0 g / cm 3 .

[0029] Preferably, the glass has a ratio of density ρ to refractive index n d (ρ / n d ) of not more than 2.0 g / cm3 , preferably not more than 1.97 g / cm 3 , preferably not more than 1.95 g / cm 3 In some advantageous embodiments, the glass has a ratio of density ρ to refractive index n d (ρ / n d ) of not more than 1.93 g / cm 3 , preferably not more than 1.92 g / cm 3 or not more than 1.91 g / cm 3 In some advantageous embodiments, the glass has a ratio of density ρ to refractive index n d (ρ / n d ) of not more than 1.90 g / cm 3 , preferably not more than 1.89 g / cm 3 on.

[0030] Preferably, the optical glass according to the invention has a ratio of Abbe number v d to density ρ(v d / ρ) of 4.5 cm 3 / g up to 7.5 cm 3 / g, preferably 4.8 cm 3 / g up to 7.3 cm 3 / g or preferably 5.0 cm 3 / g up to 7.0 cm 3 / g, particularly preferably 5.1 cm3 / g up to 6.5 cm 3 / g on.

[0031] Preferably, the glass has a product of Abbe number v d and density ρ of less than 120 g / cm 3 , preferably less than 100 g / cm 3 , particularly preferably less than 90 g / cm 3 and preferably more than 50 g / cm 3 , preferably more than 55 g / cm 3 , particularly preferably more than 60 g / cm 3 .

[0032] According to the invention, the glass has an 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 used in very large amounts, the refractive indices according to the invention cannot be achieved. The glass preferably contains at least 10.0 mol%, more preferably at least 12.0 mol%, more preferably at least 13.0 mol%, at least 15.0 mol%, at least 17.0 mol%, at least 19.0 or at least 22.0 mol% SiO2. The glass has less than 30.0 mol%, preferably not more than 29.5 mol%, more preferably not more than 27.0 mol%, particularly preferably not more than 25.0 mol%, not more than 23.0 mol%, or not more than 20.0 mol% SiO2. In advantageous embodiments, the glass contains from 13.0 ml% to < 30.0 mol%, preferably 13.0 mol% to 29.5 mol%, preferably from 15.0 mol% to 27.0 mol% or to 25.0 mol% SiO2.

[0033] B2O3 also acts as a glass former. In the glass system according to the invention, it can contribute to lowering the temperature point T maxto reduce. Preferably, the glass contains 0 mol% to 8.0 mol%, preferably from 0 mol% to 5.0 mol% or from 1.0 mol% to 5.0 mol% B2O3. Some advantageous variants can contain at least 1.0 mol% or 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%, preferably no more than 6.5 mol%, preferably no more than 5.0 mol%, more preferably no more than 3.0 mol%, preferably no more than 2.0 mol%. Some advantageous variants have a B2O3 content of 1.0 mol% to 6.5 mol%, preferably of 1.5 mol% to 5.0 mol% or preferably of 2.0 mol% to 3.0 mol% and / or a molar ratio of B2O to SiO2 of at least 0.09, preferably at least 0.10, more preferably at least 0.12, preferably at least 0.15 or 0.20 and preferably of less than 0.50, preferably less than 0.45, more preferably less than 0.35 and particularly preferably less than 0.30.Some advantageous variants contain no more than 0.5 mol%, preferably less than 0.1 mol%, of B2O3. Some advantageous variants are free of B2O3.

[0034] The glass of this invention contains Nb2O5 and TiO2. Niobium-containing glasses have a reputation for exhibiting poorer internal transmission in the near-UV / visible spectral range and, in the presence of TiO2, for having a strong tendency toward interfacial crystallization. These disadvantages do not occur with the glass described herein, or only to a controllable extent. These components result in a high refractive index with a moderate and reduced density. The glass preferably has a molar ratio of Nb2O5 to TiO2 of less than 0.9, more preferably less than 0.7, particularly preferably less than 0.6 and / or at least 0.05, preferably at least 0.06, further preferably at least 0.07, or at least 0.25. Some advantageous variants have a molar ratio of Nb2O5 to titanium of 0.05 to 0.25, preferably from 0.07 to 0.20.Some advantageous variants have a molar ratio of Nb2O5 to TiO2 of 0.25 to 0.9, preferably of 0.3 to 0.7, further preferably of 0.35 to 0.65 or up to 0.60.

[0035] Preferably, the glass contains at least 1.5 mol%, preferably at least 2.0 mol%, preferably at least 5.0 mol%, at least 7.0 mol%, at least 8.0 mol%, or at least 10.0 mol% and / or no more than 17.0 mol%, preferably no more than 15.0 mol%, preferably no more than 12.0 mol%, no more than 10.0 mol%, or no more than 9.0 mol% Nb2O5. In some embodiments, the glass contains from 2.0 mol% to 10.0 mol%, preferably from 3.5 mol% to 9.0 mol% Nb2O5. In some advantageous embodiments, the glass contains from 5.0 mol% to 17.0 mol%, preferably from 6.0 mol% to 15.0 mol%, or from 8.0 mol% to 17.0 mol% Nb2O3, also preferably from 10.0 mol% to 15.0 mol%.

[0036] The glass preferably contains at least 18.0 mol%, preferably at least 20.0 mol% or preferably at least 23.0 mol%, further preferably at least 25.0 mol% and / or not more than 55.0 mol%, preferably not more than 50.0 mol%, further preferably not more than 48.0 mol% TiO2. In some embodiments, the glass contains at least 30.0 mol%, preferably at least 35.0 mol%, more preferably at least 40.0 mol% and / or not more than 55.0 mol%, preferably not more than 50.0 mol%, further preferably not more than 48.0 mol% TiO2. In some advantageous embodiments, the glass contains 35.0 mol% to 55.0 mol%, preferably 40.0 mol% to 50.0 mol%, further preferably 42.0 mol% to 48.0 mol% of TiO2. In some advantageous embodiments, the glass contains 20.0 to 35.0 mol%, preferably 23.0 mol% or 25.0 mol% to 30.0 mol% of TiO2.

[0037] Preferably, the glass also comprises BaO in addition to Nb2O3 and TiO2, wherein the glass preferably has a total content of BaO, Nb2O5 and TiO2 of at least 40.0 mol%, preferably of at least 43.0 mol% or of at least 45.0 mol%, further preferably of at least 50.0 mol% and / or not more than 65.0 mol%, preferably not more than 62.0 mol%, preferably not more than 60.0 mol%.

[0038] Optionally, the glass can contain Al2O3. Al2O3 can contribute to the chemical resistance of the glass. The glass can contain from 0 to 5.0 mol% or up to 3.0 mol%, or up to 2.0 mol% or up to 1.0 mol% Al2O. S Some advantageous embodiments contain less than 0.5 mol% Al2O3. Preferred variants are free of Al2O3. Some advantageous variants can contain 0.5 mol% to 3.0 mol%, preferably 0.75 mol% to 2.5 mol.

[0039] The glass may contain ZrO2. ZrO2 contributes to achieving the high refractive index, but it also increases the crystallization tendency of the glass, so its content is preferably limited to no more than 5.5 mol%, preferably no more than 5.0 mol%, likewise preferably no more than 4.5 mol% or no more than 4.0 mol%, more preferably no more than 3.5 mol% or no more than 3.0 mol%. In some advantageous embodiments, the glass contains 1.5 mol% to 5.5 mol% or up to 5.0 mol%, preferably from 2.0 mol% to 4.0 mol% of ZrO2. Some embodiments are free of ZrO2.

[0040] The glass preferably contains Li2O, Na2O, and / or K2O. The glass preferably has a total R2O content, where R2O = Li2O, Na2O, and / or K2O, of more than 0 mol%, preferably at least 2.0 mol%, further preferably at least 4.0 mol%, particularly preferably at least 8.0 mol% or at least 10 mol%, and / or not more than 25.0 mol%, preferably not more than 23.0 mol%. The alkali metal oxides mentioned contribute to good processability; however, excessively high contents can reduce chemical resistance and excessively lower the refractive index. Some embodiments are free of R2O.

[0041] 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 K2O and at least one of Li2O and Na2O. In some embodiments, the glass comprises Li2O, Na2O, and K2O.

[0042] 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 from 0 mol% to 23.0 mol%, preferably up to 21.0 mol%, further preferably up to 18.0 mol%, up to 17.0 mol% or up to 16.0 mol%, and further preferably up to 15.0 mol%. In some advantageous embodiments, the glass contains 0 mol%, or at least 1.0 mol%, preferably at least 3.0 mol% or at least 4.0 mol% and / or not more than 5.0 mol%, preferably not more than 3.5 mol%, not more than 3.0 mol%, particularly preferably not more than 2.0 mol% Li2O. In some embodiments, the glass contains at least 5.0 mol% and no more than 17.0 mol%, preferably no more than 15.0 mol%, further preferably no more than 12.0 mol%, or no more than 10.0 mol%, further preferably no more than 7.5 mol% Li2O. In some advantageous embodiments, the glass is free of Li2O.

[0043] In some advantageous embodiments, the glass contains Na2O. The Na2O content is preferably in the range from 0 mol% to 15.0 mol%, preferably from 1.0 mol% to 12.5 mol% or to 12.0 mol%. In some advantageous embodiments, the glass contains at least 1.0 mol%, preferably at least 1.5 mol%, preferably at least 2.0 mol%, at least 3.0 mol%, at least 4.0 mol% or at least 5.0 mol% and / or not more than 15.0 mol%, preferably not more than 12.5 mol% or not more than 12.0 mol%, preferably not more than 10.0 mol%, not more than 8.0 mol% or not more than 6.0 mol% Na2O. In some embodiments, the glass contains no more than 5.0 mol%, no more than 4.0 mol%, or no more than 3.0 mol% Na2O. In some advantageous embodiments, the glass is free of Na2O.

[0044] In some advantageous embodiments, the glass contains K2O. The K2O content is preferably in the range from 0 mol% or more than 0 mol% to 12.0 mol%, preferably from 1.0 mol% to 10.0 mol%. In some advantageous embodiments, the glass contains at least 1.0 mol%, at least 2.0 mol% or at least 3.0 mol% and / or not more than 10.0 mol%, preferably not more than 8.0 mol% or not more than 6.0 mol%, further preferably not more than 5.0 mol% or not more than 4.0 mol% K2O. In some advantageous embodiments, the glass is free of K2O.

[0045] In advantageous embodiments, the glass contains at least one alkaline earth oxide RO, where 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 temperature and stabilize the glass against crystallization without reducing the chemical resistance to the extent that alkali metal oxides do.

[0046] Preferably, the total content of MgO, CaO, and SrO is in the range of more than 0 mol% to 30.0 mol%, or more than 0 mol% to 25.0 mol%, preferably in the range of 2.0 mol% to 20.0 mol%. In some advantageous variants, the glass contains a total content of MgO, CaO, and SrO in the range of 3.0 mol% to 15.0 mol%.

[0047] 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 content of RO, where RO = MgO, CaO, SrO, and / or BaO, of 2.0 mol% to 40.0 mol%, preferably of 5.0 mol% to 35.0 mol%, preferably of 6.0 mol% to 30.0 mol%, or of 6.0 mol% to 25.0 mol%. In some advantageous embodiments, the glass contains a total content of MgO, CaO, SrO, and BaO of 18.0 mol% to 30.0 mol%, preferably of 19.0 mol% to 27.0 mol%, further preferably of 20.0 mol% to 26.0 mol% or of 21.0 mol% to 25.0 mol%. In some advantageous embodiments, the glass contains a total content of MgO, CaO, SrO, and BaO of 5.0 mol% to 20.0 mol%, preferably of 8.0 mol% to 18.0 mol%, further preferably of 10.0 mol% to 15.0 mol%.

[0048] The glass preferably contains BaO. Advantageously, the glass contains from 3.5 mol% to 15.0 mol%, preferably from 4.0 mol% to 13.0 mol%, further preferably from 4.0 mol% to 11.0 mol%, more preferably 4.5 mol% to 10.0 mol% BaO. In some embodiments, the glass contains at least 3.5 mol%, preferably at least 4.0 mol%, at least 4.5 mol% or at least 5.0 mol% and / or no more than 12.0 mol%, preferably no more than 11.0 mol%, likewise preferably no more than 10.0 mol% or no more than 8.0 mol% BaO.

[0049] The MgO content is preferably in the range from 0 mol% to 5.0 mol%, preferably from 0.5 mol% to 4.5 mol%, or from 1.0 mol% to 3.0 mol%. Some advantageous variants contain less than 3.0 mol%, preferably less than 2.0 mol%, of MgO. Some advantageous variants are MgO-free.

[0050] The CaO content is preferably in the range from 0 mol% to 30.0 mol%, preferably from 0 mol% to 25.0 mol%. In some advantageous embodiments, the glass contains from 2.0 mol% to 20.0 mol%, preferably from 3.0 mol% to 15.0 mol%, and likewise preferably from 4.0 mol% to 12.0 mol% CaO. Some advantageous embodiments contain no more than 15.0 mol%, preferably no more than 12.0 mol%, no more than 11.0 mol%, no more than 10.0 mol%, or no more than 8.0 mol% CaO. Some advantageous embodiments are free of CaO.

[0051] The SrO content is preferably in the range from 0 mol% to 7.0 mol% or 6.5 mol%. In some advantageous embodiments, the SrO content is in the range from 0 mol% or 1.0 mol% to 5.0 mol%, preferably from 1.5 mol% to 4.0 mol%. Some advantageous embodiments are free of SrO.

[0052] The glass preferably contains a total content of RO + R2O in the range of 20.0 mol% to 40.0 mol%, preferably 25.0 mol% to 35.0 mol%, preferably 26.0 mol% to 33.0 mol%. Glasses with the stated total content of RO and R2O exhibit favorable glass formation properties. If the RO and R2O content is too low, the glasses have an unfavorably high melting temperature; if the contents are too high, the crystallization tendency of the glasses increases.

[0053] The glass can optionally contain ZnO. However, ZnO is hazardous to water and can attack tanks and crucibles; therefore, according to the invention, the ZnO content is limited to less than 5.0 mol%. In advantageous embodiments, the glass has a ZnO content of 0 to 5.0 mol%, or more than 0 mol% to 4.5 mol%, preferably from 0.5 mol% to 3.5 mol%, more preferably from 0.7 mol% to 2.5 mol%, and particularly preferably from 0.8 mol% to 2.0 mol%. Some advantageous variants are free of ZnO.

[0054] Optionally, the glass can contain Ln2O3, where Ln2O3 = La2O3, Gd2O3, Y2O3, and / or Yb2O3. These components can generally be used to increase the refractive index of the glasses, but glasses containing Ln2O3 typically have a higher density. Therefore, the Ln2O3 content is limited to less than 5.0 mol%, preferably less than 2.0 mol%, and more preferably less than 1.0 mol%. The glass is preferably free of Ln2O3.

[0055] The addition of conventional refining agents is not necessary, as the melt has a low viscosity at the temperatures required for melting. If refining agents such as As2O3, Sb2O3, SO3, F, and / or Cl are added, their content can be significantly reduced, e.g., to < 0.1 mol%. Pure physical refining is also possible and advantageous. Optionally, the glass can contain one or more of the following components with a refining effect 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 CI 0.0 to 1.0

[0056] Sulfate (SO3) may be present in the glass in small amounts to help stabilize the higher oxidation states of polyvalent ions. If present, the amount is at least 0.01 mol%. Higher sulfate contents increase the risk of severe blistering in the glass and the risk of platinum leaching into the glass. Therefore, the sulfate content can advantageously be a maximum of 0.5 mol%, preferably a maximum of 0.1 mol%, and most preferably a maximum of 0.05 mol%. The glass is preferably SO3-free.

[0057] In some embodiments, F can have a positive effect on the transmission of the glass by stabilizing higher oxidation states of polyvalent ions.

[0058] 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 via the raw material along with the ZrO2 component. When using a very pure ZrO2 raw material, the glass is advantageously HfO2-free.

[0059] In an advantageous embodiment, the glass has the following components in mol%: SiO2 < 30,0 B2O3 0 - 8,0 Nb2O5 + TiO2 + BaO 40,0 - 65,0 R2O + RO 20,0 - 40,0 ZnO 0 - 4,5 Ln2O3 < 2,0

[0060] In an advantageous embodiment, the glass has the following components in mol%: SiO2 < 30,0 preferred 13.0 - < 29.5 B2O3 0 - 8,0 preferred 0 - 5 Nb2O3 + TiO2 + BaO 40,0 - 65,0 preferred 43.0 - 62.0 K2O > 0 - 12,0 preferably 1.0 - 10.0 R2O + RO 25,0 - 35,0 preferably 26.0 - 33.0 ZnO 0-4,5 preferably 0 - 3.5 ZrO2 0 - 5,5 preferably 1.5 - 5.0 Ln2O3 < 2.0 mol% preferred 0

[0061] In an advantageous embodiment, the optical glass has the following components in mol%: SiO2 13,0 - < 30,0 preferred 13.0 - 27.0 B2O3 0-5,0 preferably 0 - 3.0 Nb2O5 1,5 - 17,0 preferred 2.0 - 15.0 TiO2 20,0 - 55,0 preferably 25.0 - 48.0 ZrO2 0-5,5 preferably 1.5 - 5.0 Al2O3 0 - 2,0 preferably < 0.5 ZnO 0 - 4,5 preferably > 0 - 4.5 MgO 0-5,0 preferably 0 - 3.0 CaO 0 - 20,0 preferred 2.0 -15.0 SrO 0-6,5 preferred 0 BaO 4,0 - 10,0 preferably 4.5 - 10.0 Li2O 0 - 17,0 preferably 0 - 15.0 Na2O 0 - 15,0 0 - 12,5 K2O > 0 - 12,0 preferably 1.0 - 10.0

[0062] In an advantageous embodiment, the optical glass has the following components in mol%: SiO2 13,0 - 25,0 preferably 15.0 - 20.0 B2O3 0-5,0 preferably 0 - 3.0 Nb2O5 2,0 - 10,0 preferably 3.5 - 9.0 TiO2 40,0 - 50,0 preferably 42.0 - 48.0 ZrO2 2,5 - 5,5 preferably 3.0 - 5.0 Al2O3 0 - 2,0 preferred 0 ZnO > 0 - 4,5 preferably 0.5 - 3.5 MgO < 3,0 preferred 0 CaO 1,0 - 10,0 preferably 3.0 - 8.0 SrO 0 BaO 4,0 - 12,0 preferably 5.0 - 10.0 Li2O 0-5,0 preferred 0 - 3.0, still preferred 1.0 - 3.0 Na2O 3,0 - 15,0 preferred 5.0 - 12.5 K2O 1,0 - 10,0 preferably 2.0 - 8.0

[0063] In an advantageous embodiment, the optical glass has the following components in mol%: SiO2 19,0 - 30,0 preferably 22.0 - 27.0 B2O3 0 - 2,0 preferred 0 Nb2O5 8,0 - 17,0 preferred 10.0 - 15.0 TiO2 20,0 - 35,0 preferably 25.0 - 30.0 ZrO2 < 5,0 preferably 2.0 - 4.0 Al2O3 0 - 2,0 preferred 0 ZnO > 0 - 4,5 preferably 0.5 - 2.0 MgO < 2,0 preferred 0 CaO 1,0 - 15,0 preferred 3.0 - 11.0 SrO 0 BaO 3,5 - 10,0 preferred 4.0 - 8.0 Li2O 8,0 - 18,0 preferred 10.0 - 16.0 Na2O < 4,00 preferably 0.0 - 3.0 K2O > 0 - 6,0 preferably 1.0 - 5.0

[0064] In an advantageous embodiment, the optical glass has the following components in mol%: SiO2 15,0 - 25,0 preferably 17.0 - 23.0 B2O3 0 - 2,0 preferred 0 Nb2O5 5,0 - 12,0 preferably 7.0 - 10.0 TiO2 33,0 - 42,0 preferably 35.0 - 40.0 ZrO2 < 5,0 preferably 2.0 - 4.0 Al2O3 0 - 2,0 preferred 0 ZnO > 0 - 4,5 preferably 0.5 - 2.0 MgO < 2,0 preferred 0 CaO 3,0 - 15,0 preferably 6.0 - 12.0 SrO 0 BaO 3,5 - 11,0 preferably 5.0 - 10.0 Li2O 3,0 - 11,0 preferred 4.0 - 9.0 Na2O 1,0 - 10,0 preferably 2.0 - 8.0 K2O > 0 - 6,0 preferably 1.0 - 5.0

[0065] 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 of the components listed in the above tables. In one embodiment, the glass consists essentially entirely of these components.

[0066] Preferably, the glass is essentially free of bismuth (Bi2O3) and / or lead (PbO). The addition of bismuth would disproportionately increase the density of the glass. Furthermore, bismuth ions are reduced to elemental bismuth even at relatively low temperatures in the range of 1000°C, resulting in a strong gray coloration of the glass. PbO is also omitted due to its negative influence on low density. Furthermore, it is considered a toxic component.

[0067] Due to the high contents of niobium and titanium, expensive components such as tantalum (Ta2O5) and / or tungsten (WO3) and / or germanium (GeO2) are not required or are only required in small amounts in order to obtain a glass with the desired high refractive index.

[0068] The glass is preferably free of phosphate (P2O5), as it significantly reduces the melt and reduces transmission by reducing TiO2 and / or Nb2O3. Furthermore, a reducing melt can corrode platinum, increasing the ingress of platinum into the melt and leading to coloration or increased scattering of the glass.

[0069] Optionally, the glass 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, based on the respective cations. 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 not to deliberately add these components, either individually or in combination, to the glass.

[0070] 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 amounts. According to the invention, non-significant amounts are amounts of less than 100 ppm, preferably less than 50 ppm, and most preferably less than 10 ppm (w / w).

[0071] Preferably, the optical glass has a pure transmission (τ1 (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.

[0072] The pure transmittance or pure transmittance can be measured using methods familiar to the expert, for example, according to DIN 5036-1:1978. In this description, the pure transmittance 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 transmittance value refers.

[0073] Unless otherwise stated or obvious to a person skilled in the art, measurements described herein are carried out at 20°C and 101.3 kPa atmospheric pressure.

[0074] In a further aspect, the invention relates to an optical glass having a refractive index n d of more than 1.95 and preferably not more than 2.05, an Abbe number of d of less than 32 and a temperature T maxof not more than 1350°C, comprising at least SiO2, TiO2 and Nb2O5, comprising less than 30.0 mol% SiO2, less than 5.0 mol% ZnO and less than 5.0 mol% Ln2O3, where Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3, and having a K2O content of more than 0 mol%.

[0075] The detailed explanations and preferred embodiments given above for the glass according to the invention apply analogously in this context.

[0076] In a further aspect, the invention relates to an optical glass having a refractive index n d of more than 1.95 and preferably not more than 2.05, an Abbe number of d of less than 32 and a temperature T maxof not more than 1350°C, which comprises at least SiO2, TiO2 and Nb2O5, comprising less than 30.0 mol% SiO2, less than 5.0 mol% ZnO and less than 5.0 mol% Ln2O3, where Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3, and has a K2O content of more than 0 mol% and a B2O3 content of not more than 0.5 mol%, preferably free of B2O3.

[0077] The detailed explanations and preferred embodiments given above for the glass according to the invention apply analogously in this context.

[0078] In a further aspect, the invention relates to an optical glass having a refractive index n d of more than 1.95 and preferably not more than 2.05, an Abbe number of d of less than 32 and a temperature T maxof not more than 1350°C, comprising at least SiO2, TiO2 and Nb2O3, comprising less than 30.0 mol% SiO2, less than 5.0 mol% ZnO and less than 5.0 mol% Ln2O3, where Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3, wherein the glass has a K2O content of more than 0 mol% and a molar ratio of B2O3 to SiO2 of at least 0.09.

[0079] The detailed explanations and preferred embodiments given above for the glass according to the invention apply analogously in this context.

[0080] In a further aspect, the invention relates to an optical glass having a refractive index n d of more than 1.95 and preferably not more than 2.05, an Abbe number of d of less than 32 and a temperature T maxof not more than 1350°C, comprising at least SiO2, TiO2 and Nb2O5, comprising less than 30.0 mol% SiO2, less than 5.0 mol% ZnO and less than 5.0 mol% Ln2O3, where Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3, wherein the glass has a B2O3 content of not more than 0.5 mol%, preferably is free of B2O3.

[0081] The detailed explanations and preferred embodiments given above for the glass according to the invention apply analogously in this context.

[0082] In a further aspect, the invention relates to an optical glass having a refractive index n d of more than 1.95 and preferably not more than 2.05, an Abbe number of d of less than 32 and a temperature T maxof not more than 1350°C, comprising at least SiO2, TiO2 and Nb2O5, comprising less than 30.0 mol% SiO2, less than 5.0 mol% ZnO and less than 5.0 mol% Ln2O3, where Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3, wherein the glass has a molar ratio of B2O; to SiO2 of at least 0.09.

[0083] The detailed explanations and preferred embodiments given above for the glass according to the invention apply analogously in this context.

[0084] In one aspect, the invention relates to a glass article comprising or consisting of the glass according to the invention. The glass article can have different shapes. Optionally, the article has the shape - a glass substrate, in particular as a component of a stack of substrates, for an optical component, 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 asphere, and / or - an optical waveguide, in particular a fiber or plate.

[0085] In a further aspect, the glass article according to the invention is a chemically strengthened glass article, in particular a chemically strengthened glass substrate, a chemically strengthened wafer, and / or a chemically strengthened lens. It will be understood by those skilled in the art that these are glass articles comprising the optical glasses according to the invention that are chemically strengthenable.

[0086] For the purposes of the present disclosure, a glass that is chemically hardenable is understood to mean 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 in such a way that a compressive stress zone is now built up in the surface layer, which is achieved by the exchange of ions with smaller radii for ions with larger radii. For this purpose, the glass article is immersed in a so-called ion exchange bath, for example a molten salt bath, wherein the ion exchange bath comprises the ions with the larger ionic radii, in particular potassium and / or sodium ions, so that they 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.

[0087] This creates a compressive stress zone. This can be described by the characteristic values ​​of compressive stress, also referred to as "compressive stress" or "CS" for short, and the compressive stress depth, also referred to as "depth of layer" or "DoL" for short. This compressive stress depth (DoL) is well known to those skilled in the art and, in the context of the present disclosure, refers to the depth at which the stress curve crosses zero stress.

[0088] Higher mechanical strengths can be achieved with such chemically strengthened glass articles.

[0089] Preferably, the manufacture of the chemically strengthened glass article comprises the following steps: a) Providing the glass article described above, b) carrying out at least one first ion exchange, c) optionally carrying out a second ion exchange.

[0090] Preferably, the first ion exchange takes place for a period 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 and 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.

[0091] In some advantageous embodiments, a second ion exchange is then carried out 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 and 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.

[0092] In a further 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 conventional optics. Alternatively or additionally, the glass or glass article described herein can be used as a wafer, lens, or optical waveguide.

[0093] The glasses according to the invention can be melted from commercial raw materials. For example, it is possible to melt the glasses in a device such as that described in the as yet unpublished DE 10 2020 120168 A1. Examples:

[0094] The compositions shown in Tables 1 to 6 below were melted and their properties investigated. Tables 1 to 5 show exemplary embodiments according to the invention (Examples 1 to 30) and Table 6 shows comparative examples (Comparison Examples A and B). The internal transmission was determined for some of the glasses. Compositions and properties: Table 1: Mol% 1 2 3 4 5 6 7 B2O3 5,00 0,00 2,24 2,95 2,64 2,71 2,10 BaO 7,00 7,80 7,77 8,16 9,03 6,77 8,98 TiO2 28,00 42,34 43,61 36,00 43,71 43,28 43,48 Nb2O5 14,50 3,74 2,42 7,71 3,86 3,82 3,84 SiO2 19,00 18,58 17,93 17,71 15,82 16,25 16,79 Al2O3 0,00 0,00 0,00 0,00 0,00 0,00 0,00 MgO 0,00 2,08 2,22 4,08 2,26 2,26 2,25 CaO 19,50 15,09 11,09 14,97 9,71 9,71 10,11 Li2O 0,00 0,00 0,00 0,00 0,00 0,00 0,00 Na2O 4,00 0,00 1,48 2,72 4,52 4,52 4,49 K2O 0,00 5,57 5,92 1,81 3,01 3,01 2,99 ZnO 0,00 1,04 1,11 0,00 1,58 1,58 1,12 SrO 0,00 0,00 0,00 0,00 0,00 2,26 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 3,00 3,75 4,21 3,87 3,87 3,83 3,85 sum 100 100 100 100 100 100 100 B2O3 / SiO2 0,26 0,00 0,13 0,17 0,17 0,17 0,13 <h2 style=";text-align:left;direction:ltr">(TiO2+ZrO2+2*Nb<h2 style=";text-align:left;direction:ltr"> 20 <h2 style=";text-align:left;direction:ltr"> O5+2*Ta2O5+2*Al2O3 + SiO2+B2O3) / (R2O+RO+2*Ln2O3) 2,75 2,36 2,56 2,39 2,59 2,58 2,56 Characteristics n d 2,018 1,967 2,004 2,006 1,993 1,994 Vd 21,0 18,7 20,8 20,6 20,7 20,4 Tg 641 T max [°C] 1300 1300 1300 1300 1300 1300 1300 Density [g / cm 3 ] 3,97 3,75 3,69 3,89 3,83 3,78 Density × v d [g / cm 3 ] 83,5 69,0 80,9 78,8 78,2 t i (10 mm, 460 nm) 0,84 Table 2: Mol% 8 9 10 11 12 13 14 B2O3 0,00 0 0 1,82 0 0 0 BaO 7,84 7,84 6,53 6,65 6,53 8,14 6,53 TiO2 46,74 45,96 45,96 46,56 46,22 45,47 45,44 Nb2O5 4,12 4,06 4,06 4,11 4,08 4,01 4,01 SiO2 17,31 17,30 17,30 14,57 17,30 18,01 17,29 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 4,31 4,31 5,62 5,72 5,62 7,00 5,61 Li2O 0,00 0,00 0,00 0,00 1,52 1,22 1,52 Na2O 6,10 7,62 10,67 12,41 10,67 8,54 10,66 K2O 9,15 7,62 4,57 3,10 3,05 2,44 3,05 ZnO 0,91 0,91 0,91 0,93 0,91 1,14 0,91 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 3,51 4,38 4,38 4,12 4,09 4,03 4,97 sum 100 100 100 100 100 100 100 B2O3 / SiO2 0,00 0,00 0,00 0,13 0,00 0,00 0,00 (TiO2+ZrO2+2*Nb2O5+2*Ta2O5+2*Al2O3 +SiO2+B2O3) / (R2O+RO+2*Ln2O3) 2,77 2,77 2,77 2,70 2,77 2,76 2,77 Characteristics n d 1,958 1,958 1,984 1,983 1,987 1,997 1,983 Vd 20,8 20,6 20,2 20,2 19,7 20,3 20,2 Tg T max [°C] 1300 1300 1300 1300 1300 1300 1300 Density [g / cm 3 ] 3,63 3,66 3,67 3,69 3,70 3,78 3,70 Density × v d [g / cm 3 ] 75,5 75,4 74,1 74,5 72,9 76,7 74,7 t i (10 mm, 460 nm) Table 3: Mol% 15 16 17 18 19 20 21 B2O3 0 0 0 0 0 0 0 BaO 5,45 5,33 5,14 6,86 8,74 6,98 6,05 TiO2 23,53 27,24 28,65 28,83 38,75 37,88 38,72 Nb2O5 14,38 13,62 11,72 11,80 8,30 8,12 7,16 SiO2 29,41 24,29 24,48 24,44 18,82 20,60 21,01 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 0,00 4,26 8,08 9,93 7,87 9,60 10,38 Li2O 21,79 14,92 14,57 11,51 6,56 5,89 5,84 Na2O 0,00 2,13 0,00 0,00 3,93 5,24 5,84 K2O 0,00 4,26 2,57 2,03 2,62 1,96 1,30 ZnO 0,00 1,07 1,47 1,26 0,87 0,87 0,86 SrO 5,45 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 0,01 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 0,00 2,87 3,32 3,35 3,53 2,85 2,79 sum 100 100 100 100 100 100 100 B2O3 / SiO2 0,00 0,00 0,00 0,00 0,00 0,00 0,00 (TiO2+ZrO2+2*Nb2O5+2*Ta2O5+2*Al2O3 +SiO2+B2O3) / (R2O+RO+2*Ln2O3) 2,50 2,64 2,63 2,65 2,61 2,61 2,61 Characteristics n d 1,965 1,980 1,981 1,994 2,015 2,004 1,999 Vd 22,2 22 21,6 21,3 20,6 20,5 20,4 Tg 589 591 T max [°C] 1300 1300 1300 1300 1300 1300 1300 Density [g / cm 3 ] 3,78 3,79 3,87 3,89 3,82 3,77 Density × v d [g / cm 3 ] 83,1 81,9 82,4 80,2 78,3 t i (10 mm, 460 nm) 81,3 93,4 87,1 Table 4: Mol% 22 23 24 25 26 27 28 B2O3 0 0 0 1,97 5,00 0 2,55 BaO 7,71 8,02 7,71 8,12 7,00 6,51 8,04 TiO2 43,04 36,85 43,04 44,02 26,00 45,73 44,70 Nb2O5 3,80 7,90 3,80 3,88 14,50 4,03 3,94 SiO2 20,42 21,23 20,42 15,78 19,00 18,02 15,30 Al2O3 0,00 0,00 0,00 0,00 0,00 0,00 0,00 MgO 1,93 2,00 1,93 2,03 0,00 0,00 2,01 CaO 8,29 8,62 8,29 9,14 25,50 8,63 8,64 Li2O 0,00 3,31 0,00 0,00 0,00 1,22 0,00 Na2O 2,89 3,31 4,82 7,11 0,00 8,54 7,54 K2O 6,75 3,41 4,82 3,05 0,00 2,44 2,51 ZnO 1,35 1,40 1,35 1,02 0,00 1,14 1,41 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 3,81 3,96 3,81 3,90 3,00 3,74 3,36 sum 100 100 100 100 100 100 100 B2O3 / SiO2 0,00 0,00 0,00 0,13 0,26 0 0,17 (TiO2+ZrO2+2*Nb2O5+2*Ta2O5+2*Al2O3 +SiO2+B2O3) / (R2O+RO+2*Ln2O3) 2,71 2,71 2,71 2,49 2,52 2,76 2,57 Characteristics n d 1,960 1,997 1,965 1,988 2,000 1,996 Vd 21 21,5 20,8 20,8 20,6 21,5 Tg T max [°C] 1300 1300 1300 1300 1300 1300 1300 Density [g / cm 3 ] 3,68 3,87 3,71 3,76 3,72 3,75 Density × v d [g / cm 3 ] 77,4 83,2 77,2 78,3 76,6 80,7 t i (10 mm, 460 nm) Table 5: Mol% 29 30 B2O3 0,00 0,00 BaO 5,78 6,06 TiO2 38,98 38,74 Nb2O5 7,21 7,16 SiO2 22,12 21,02 Al2O3 0,00 0,00 MgO 0,00 0,00 CaO 9,57 10,03 Li2O 4,95 5,19 Na2O 6,19 6,49 K2O 1,24 1,30 ZnO 1,16 1,21 SrO 0,00 0,00 As2O3 0,00 0,00 Y2O3 0,00 0,00 Sb2O3 0,00 0,00 La2O3 0,00 0,00 Gd2O3 0,00 0,00 ZrO2 2,81 2,79 sum 100 100 B2O3 / SiO2 0 0 (TiO2+ZrO2+2*Nb2O5+2*Ta2O5+2*Al2O3 +SiO2+B2O3) / (R2O+RO+2*Ln2O3) 2,83 2,65 Characteristics n d 2,001 1,999 Vd 20,9 21,2 Tg T max [°C] 1300 1300 Density [g / cm 3 ] 3,77 3,777 Density × v d [g / cm 3 ] 78,8 80,0 t i (10 mm, 460 nm) Table 6: Mol% A B B2O3 1,42 0,00 BaO 4,27 4,21 TiO2 26,00 24,03 Nb2O5 14,08 14,68 SiO2 25,61 36,04 Al2O3 0,00 0,00 MgO 0,00 0,00 CaO 24,18 0,00 Li2O 0,00 16,83 Na2O 1,58 0,00 K2O 0,00 0,00 ZnO 0,00 0,00 SrO 0,00 4,21 As2O3 0,00 0,00 Y2O3 0,00 0,00 Sb2O3 0,00 0,00 La2O3 0,00 0,00 Gd2O3 0,00 0,00 ZrO2 2,85 0,00 sum 100 100 B2O3 / SiO2 0,06 0,00 (TiO2+ZrO2+2*Nb2O5+2*Ta2O5+2*Al2O3 +SiO2+B2O3) / (R2O+RO+2*Ln2O3) 2,80 3,54 Characteristics n d Vd Tg T max [°C] 1300 1350 Density [g / cm 3 ] Density × v d [g / cm 3 ] t i (10 mm, 460 nm)

[0095] 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 have a low T maxWithin the scope of the invention, it was found that the glasses according to the invention have a low tendency to crystallize. Comparative examples A and B, on the other hand, have a high tendency to crystallize.

[0096] Although the present invention has been described using preferred embodiments, it is not limited thereto but can be modified in many ways. QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] DE 10 2020 120168 A1

[0093] Cited non-patent literature

[0000] DIN 5036-1:1978

[0072]

Claims

[1] Optical glass with a refractive index n d of more than 1.95 and preferably not more than 2.05, an Abbe number of d of less than 32 and a temperature T max of not more than 1350°C, comprising at least SiO2, TiO2 and Nb2O5, comprising less than 30.0 mol% SiO2, less than 5.0 mol% ZnO and less than 5.0 mol% Ln2O3, where Ln2O3 = Y2O3, La2O3, Gd2O3 and / or Yb2O3, wherein the glass satisfies at least one of the following conditions: (i) a K2O content of more than 0 mol%, (ii) a B2O3 content of not more than 0.5 mol%, (iii) a molar ratio of B2O3 to SiO2 of at least 0.

09. [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, where 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 Abbe number v d and density ρ of less than 120 g / cm 3 , preferably less than 100 g / cm 3 particularly preferably less than 90 g / cm 3 and preferably more than 50 g / cm 3 , preferably more than 55 g / cm 3 , particularly preferably more than 60 g / cm 3 has. [4] Optical glass according to one of the preceding claims, wherein the glass contains 3.5 mol% to 15.0 mol%, preferably from 4.0 mol% to 13.0 mol% BaO. [5] Optical glass according to one of the preceding claims, wherein the glass has a total content of BaO, Nb2O5 and TiO2 of at least 40.0 mol%, preferably at least 43.0 mol% and / or not more than 65.0 mol%, preferably not more than 62.0 mol%. [6] Optical glass according to one of the preceding claims, wherein the glass has a total content of R2O, where R2O = Li2O, Na2O and / or K2O, of 2.0 mol% to 25.0 mol%, preferably of 4.0 mol% to 23.0 mol%. [7] Optical glass according to one of the preceding claims, wherein the glass has a total content of RO, where RO = MgO, CaO, SrO and / or BaO, of 6.0 mol% to 30.0 mol% and / or a total content of MgO, CaO and SrO of 2.0 mol% to 20.0 mol%. [8] Optical glass according to one of the preceding claims, wherein the glass has a total content of RO + R2O of 20.0 mol% to 40.0 mol%, preferably of 25.0 mol% to 35 mol%. [9] Optical glass according to one of the preceding claims, wherein the glass contains from 1.5 mol% to 5.5 mol%, preferably not more than 5.0 mol% ZrO2. [10] Optical glass according to one of the preceding claims, wherein the glass comprises the following components in mol%: SiO2 < 30,0 B2O3 0 - 8,0 Nb2O5 + TiO2 + BaO 40,0 - 65,0 R2O + RO 20,0 - 40,0 ZnO 0 - 4,5 Ln2O3 < 2,0 [11] Optical glass according to one of the preceding claims, wherein the glass comprises the following components in mol%: SiO2 < 30,0 preferred 13.0 - < 29.5 B2O3 0 - 8,0 preferred 0 - 5.0 Nb2O3 + TiO2 + BaO 40,0 - 65,0 preferred 43.0 - 62.0 K2O > 0 - 12,0 preferably 1.0 - 10.0 R2O + RO 25,0 - 35,0 preferably 26.0 - 33.0 ZnO 0-4,5 preferably 0 - 3.5 ZrO2 0 - 5,5 preferably 1.5 - 5.0 Ln2O3 < 2.0 mol% preferred 0 [12] Optical glass according to one of the preceding claims, wherein the glass comprises the following components in mol%: SiO2 13,0 - < 30,0 preferably 13 - 27.0 B2O3 0-5,0 preferably 0 - 3.0 Nb2O5 1,5 - 17,0 preferred 2.0 - 15.0 TiO2 20,0 - 55,0 preferably 25.0 - 48.0 ZrO2 0-5,5 preferably 1.5 - 5.0 Al2O3 0 - 2,0 preferably < 0.5 ZnO 0 - 4,5 preferably > 0 - 4.5 MgO 0-5,0 preferably 0 - 3.0 CaO 0 - 20,0 preferred 2.0 -15.0 SrO 0-6,5 preferred 0 BaO 4,0 - 10,0 preferably 4.5 - 10.0 Li2O 0 - 17,0 preferably 0 - 15.0 Na2O 0 - 15,0 0 - 12,5 K2O > 0 - 12,0 preferably 1.0 - 10.0 [13] Optical glass according to one of the preceding claims, wherein the glass has a net 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. [14] Glass article comprising an optical glass according to at least one of the preceding claims, in the form - a glass substrate, in particular as a component of a stack of substrates, for an optical component, 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 asphere, and / or - an optical waveguide, in particular a fiber or plate. [15] 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.