Glass having a high refractive index and a low density

Abstract

The invention relates to a glass having a high refractive index and a low density, the use of said glass and a method for producing it.

Description

Technical Field

[0001] This invention relates to glass with a high refractive index and low density, as well as the uses of such glass and methods of its production. Background Technology

[0002] In the field of so-called "augmented reality," glass with a high refractive index and low density is particularly needed. Augmented reality is a highly active technology development project involving many application areas, such as medicine, education, architectural engineering, transportation, and entertainment. Compared to "virtual reality," a related technology, augmented reality focuses on the tight integration of multimedia information with measurement data from "real" sensors, typically achieved by overlaying digital images onto lenses.

[0003] The technical challenge in this field stems from the simultaneous requirement of achieving good optical representation of the real world, good overlay of digital information, and good wearing comfort.

[0004] Existing technologies lack high refractive indices, typically above 2.1, while simultaneously possessing refractive indices typically below 5.25 g / cm³. 3 Glasses with relatively low density and low crystallinity. Existing glasses with desired refractive index and density values ​​are characterized by a small number of constituent phases, resulting in a regular structure and thus facilitating crystallization.

[0005] This objective is addressed through the subject matter of the patent claims. Summary of the Invention

[0006] This objective is achieved through the targeted combination of stoichiometric glasses, where glasses with the same stoichiometry also exist in crystalline form, and since the assemblies have the same topological structure, it can be assumed that the properties of the glasses and crystals are extremely similar—as verified, for example, by NMR measurements in many examples in the literature. For this purpose, specific stoichiometric glasses are selected, wherein the behavior of the objective according to the invention in a solution-like sense can be obtained using mixtures of them. In this application, these stoichiometric glasses are also referred to as “base glasses” or “compositional phases”.

[0007] Describing glass by means of the constituent phases assigned to it is not a new concept. By specifying the base glass, conclusions can be drawn about the chemical structure of the glass (see Conradt R, “Chemical structure, medium range order, and crystalline reference state of multicomponent oxide liquids and glasses,” Journal of Non-Crystalline Solids, Vol. 345-346, October 15, 2004, pp. 16-23).

[0008] Here, in this example, describing it by compositional phase has a considerable advantage because, as will be shown below, the two decisive target variables, namely density and refractive index, can be approximated well without being constrained by the components given in the compositional phase, whereas calculations from the components given in a single oxide would be very cumbersome.

[0009] The selection of a suitable constituent phase must consider that the refractive index depends on atomic polarizability, which in turn depends on the volume of individual atoms or ions. In oxide glasses, oxygen ions, in particular, contribute the most to this. Therefore, to obtain a high refractive index, oxygen ions must be packed as densely as possible. This is primarily achieved by using high-valence ions with radii so large that octahedral coordination can be achieved according to Pauling's packing rules. Furthermore, these ions should not be excessively heavy due to the required low density. When considering that the constituent phase itself should exist as a glass, while requiring these ions to be at least what is called an "imperfect glass-forming agent" in the sense of Professor Reinhardt Conradt's nomenclature (Lecture Glass-Chemie, RWTH Aachen, 2010), titanium, vanadium, niobium, and molybdenum are considered for this purpose, with vanadium being less preferred due to associated redox problems. The corresponding constituent phase is generated by a combination of imperfect glass-forming agents and network modifiers (in this case, high-valence network modifiers such as lanthanum, yttrium, or gadolinium, due to the dense packing of oxygen atoms).

[0010] Therefore, we first selected lanthanum titanate, lanthanum niobate, and optionally lanthanum molybdenum borate as constituent phases.

[0011] The boron-containing phase mentioned earlier still contains a perfect glass-forming agent. A certain proportion of this perfect glass-forming agent is required to obtain glass that does not exhibit a tendency to crystallize in ways that are technically unmanageable.

[0012] In addition, we therefore selected lanthanum borate, yttrium borate and optional gadolinium borate, as well as pure glass-forming agent boron trioxide and optional silicon dioxide as other constituent phases.

[0013] Furthermore, we selected zirconium silicate as the constituent phase. Zirconium possesses the aforementioned desired properties of high valence and appropriate radius, but it is not a glass-forming agent, thus it can only be used as a constituent phase in combination with glass-forming agents.

[0014] The sizes of the larger ions mentioned (and therefore all ions except boron and silicon) enable octahedral coordination; however, their radii vary greatly (see Robert Shanno, Revised Effective Ionic Radii and Systematic Studies of Interatomic Distances in Halides and Chalcogenides, Acta Cryst. (1976) A32, 751), which could also lead to lower and higher coordination. This effect is desirable because it eliminates the tendency for regular atomic structures and crystallization.

[0015] Therefore, the present invention relates to a glass, the composition of which is characterized by the following constituent phases:

[0016] Table 1

[0017] Composition phase Minimum (mol%) Maximum (molar percentage) Lanthanum titanate 20 80 Lanthanum niobate 10 50 Lanthanum molybdenum borate 0 60 Lanthanum borate 2 40 Yttrium borate 2 40 gadolinium borate 0 40 Zirconium silicate 2 40 Boron trioxide 2 40 silicon dioxide 0 20

[0018] Furthermore, the glass according to the invention should satisfy other conditions related to the compositional phase via formulas, wherein these relationships are explained below.

[0019] First, we specify a transformation matrix for the mutual conversion between single oxide and component data in the compositional phase.

[0020] Convert components based on constituent phases to components based on single oxides, and vice versa:

[0021] For conversion purposes, the components in the compositional phase are given in the following normalized form:

[0022] Table 2

[0023] Composition phase Chemical formula (normalized relative to a single oxide) Lanthanum titanate <![CDATA[(2La2O3·9TiO2) / 11]]> Lanthanum niobate <![CDATA[(La2O3·Nb2O5) / 2]]> Lanthanum molybdenum borate <![CDATA[(La2O3·2MoO3·B2O3) / 4 <!-- 2 -->]]> Lanthanum borate <![CDATA[(La2O3·B2O3) / 2]]> Yttrium borate <![CDATA[(Y2O3·B2O3) / 2]]> gadolinium borate <![CDATA[(Gd2O3·B2O3) / 2]]> Zirconium silicate <![CDATA[(ZrO2·SiO2) / 2]]> Boron trioxide <![CDATA[B2O3]]> silicon dioxide <![CDATA[SiO2]]>

[0024] The following individual oxides are used to convert these components into component data expressed in mole percent.

[0025] # oxides 1. <![CDATA[La2O3]]> 2. <![CDATA[Y2O3]]> 3. <![CDATA[Gd2O3]]> 4. <![CDATA[ZrO2]]> 5. <![CDATA[TiO2]]> 6. <![CDATA[Nb2O5]]> 7. <![CDATA[MoO3]]> 8. <![CDATA[B2O3]]> 9. <![CDATA[SiO2]]>

[0026] This is done with the help of the matrix given here. In this case, the matrix on its right is multiplied by the component data (mol%) relative to the base glass as a column vector:

[0027] matrix

[0028]

[0029] The glass composition, expressed in mole percent, was obtained as a result of multiplying the column vectors by the matrix.

[0030] Conversely, components expressed in mol% can be easily converted into base glass components using a corresponding inverse matrix. Of course, this is only true if the base glass components according to the invention do not result in negative values ​​in the base glass during the conversion.

[0031] The importance of the constituent phase and the selection of the constituent phase for the purposes of this invention

[0032] Within the scope described herein, the components selected for the constituent phase of the glass are as follows. Of course, the constituent phase of the glass itself is not crystalline, making it amorphous in the glass product. However, this does not mean that the amorphous constituent phase has a completely different composition from the crystalline constituent phase. As mentioned above, the topological structures of their compositions are comparable; therefore, for example, the coordination of cations associated with surrounding oxygen atoms or the interatomic distances resulting from the coordination and bond strength between these cations and surrounding oxygen atoms are also comparable. Therefore, it is possible to describe many properties of the glass of the present invention well by means of the constituent phase, especially to illustrate the benefits of the invention and the problems overcome by the invention (for this purpose, see Conradt R. above). Here, of course, not only can the corresponding crystals be used to produce the glass, but also common glass raw materials can be used, provided that the stoichiometric proportions allow for the formation of the corresponding basic glass composition.

[0033] The following describes calculation methods for calculating the aforementioned key variables (i.e., density and refractive index) based on a given component of the constituent phase. These calculation methods facilitate the selection of the components of the glass according to the invention from these constituent phases.

[0034] density

[0035] It is worth noting that the lever principle can be used to determine the molar mass M of the constituent phases. i and density and its molar ratio c i Calculate the density of glass in a very simple way:

[0036]

[0037] Here, the numerator of formula (1) is the molar mass, and the denominator is the molar volume V of the glass. mol .

[0038] The molar mass, density, and molar volume are listed in the table below.

[0039] Table 3. Molar mass, density, and molar ionic volume of the phase with normalized composition.

[0040]

[0041] Density values ​​can be found in: Optical Materials 33 (2011) 1853–1857 (2La2O3·9TiO2); Optical Materials Express 4(4) April 2014 (La2O3·Nb2O5; From the density values ​​of different La2O3 / Nb2O5 mixtures listed in the literature, it can be seen that the density of glassy La2O3·Nb2O5 produced by the corresponding rapid cooling must be the same as that of crystalline La2O3·Nb2O5); Journal of Non-Crystalline Solids 429 (2015) 171–177 (La2O3·2MoO3·B2O3); Dalton Trans., 2019, 48, 10804 (La2O3·B2O3); Applied Physics A (2019) 125:852 (Y₂O₃·B₂O₃, Gd₂O₃·B₂O₃; based on the density values ​​of the Y₂O₃·Gd₂O₃·B₂O₃ system listed in the literature, the density values ​​of 30 mol% glassy Y₂O₃, 70 mol% B₂O₃, 30 mol% glassy Gd₂O₃, and 70 mol% B₂O₃ were determined by linear interpolation; the density values ​​of 50 mol% glassy Y₂O₃, 50 mol% B₂O₃, 50 mol% glassy Gd₂O₃, and 50 mol% B₂O₃ were evaluated by quadratic interpolation based on the values ​​of glassy B₂O₃, 30 mol% glassy Y₂O₃, 70 mol% B₂O₃, 30 mol% glassy Gd₂O₃, 70 mol% B₂O₃, and glassy Y₂O₃ and glassy Gd₂O₃); Journal of Non-Crystalline Solids 69 (1985) 415-423 (ZrO2·SiO2); Journal of Non-Crystalline Solids 453 (2016) 118–124 (B2O3); Solid State Communications, Vol. 88, No. 11 / 12, pp. 1023-1027, 1993 (SiO2).

[0042] The density of the glass of the present invention, calculated according to formula (1), is preferably less than 5.30 g / cm³. 3 At most 5.25g / cm 3 At most 5.20 g / cm³ 3 At most 5.15 g / cm³ 3 At most 5.10 g / cm³ 3 At most 5.05 g / cm³ 3 At most 5.00 g / cm³ 3 At most 4.95g / cm 3 At most 4.90 g / cm³ 3 At most 4.85g / cm 3 At most 4.80 g / cm³ 3 At most 4.75g / cm 3 At most 4.70 g / cm³ 3 Or at most 4.65 g / cm 3 The density of the glass calculated according to formula (1) can be particularly 4.00 g / cm³. 3 Or higher, for example, at least 4.05, at least 4.10 g / cm³. 3 At least 4.15 g / cm³ 3 At least 4.20 g / cm 3 At least 4.25 g / cm³ 3 At least 4.30 g / cm 3 At least 4.35 g / cm 3 At least 4.40 g / cm 3 At least 4.45 g / cm 3 Or at least 4.50 g / cm 3 The density of the glass of the present invention, calculated according to formula (1), can be, for example, 4.00 g / cm³. 3 Up to 5.30 g / cm 3 Within the range, especially in the following range: 4.05 g / cm³ 3 Up to 5.25 g / cm 3 4.10 g / cm 3 Up to 5.20 g / cm 3 4.10 g / cm 3 Up to 5.15 g / cm 3 4.15g / cm 3 Up to 5.10 g / cm 3 4.20g / cm 3 Up to 5.05 g / cm 3 4.20g / cm 3 Up to 5.00 g / cm 3 4.25g / cm 3Up to 4.95 g / cm 3 4.30 g / cm 3 Up to 4.90 g / cm 3 4.30 g / cm 3 Up to 4.85 g / cm 3 4.35g / cm 3 Up to 4.80 g / cm 3 4.40 g / cm 3 Up to 4.75 g / cm 3 4.45g / cm 3 Up to 4.70 g / cm 3 Or 4.50 g / cm 3 Up to 4.65 g / cm 3 The present invention, calculated according to formula (1), can also be within, for example, the range of: 4.60 g / cm³. 3 Up to 5.25 g / cm 3 4.75g / cm 3 Up to 5.24 g / cm 3 4.78 g / cm 3 Up to 5.23 g / cm 3 4.85g / cm 3 Up to 5.21 g / cm 3 4.90 g / cm 3 Up to 5.20 g / cm 3 4.91 g / cm 3 Up to 5.19 g / cm 3 4.92g / cm 3 Up to 5.18 g / cm 3 4.93 g / cm 3 Up to 5.17 g / cm 3 4.94 g / cm 3 Up to 5.16 g / cm 3 4.95g / cm 3 Up to 5.15 g / cm 3 4.96 g / cm 3 Up to 5.14 g / cm 3 4.97g / cm 3 Up to 5.13 g / cm 3 4.98g / cm 3 Up to 5.12 g / cm 3 4.99g / cm 3 Up to 5.11 g / cm 3 Or 5.00g / cm 3 Up to 5.10 g / cm 3 .

[0043] In an embodiment of the present invention, the density of the glass calculated according to formula (1) can be 5.00 g / cm³. 3 Or greater, for example, at least 5.01 g / cm³ 3 At least 5.02 g / cm 3 At least 5.03 g / cm 3 At least 5.04 g / cm 3 At least 5.05 g / cm 3 At least 5.06 g / cm³ 3 At least 5.07 g / cm 3 At least 5.08 g / cm³ 3 At least 5.09 g / cm³ 3 Or at least 5.10 g / cm 3 The density of the glass of the present invention, calculated according to formula (1), can be specifically within the following range: 5.00 g / cm³. 3 Up to 5.30 g / cm 3 5.01 g / cm 3 Up to 5.25 g / cm 3 5.02 g / cm 3 Up to 5.20 g / cm 3 5.03 g / cm 3 Up to 5.15 g / cm 3 Or 5.04 g / cm 3 Up to 5.10 g / cm 3 .

[0044] refractive index

[0045] The refractive index (BZ) relates to a wavelength of 589.3 nm; therefore, it is typically related to "n". D The value of ''. This refractive index was calculated based on the values ​​of Shannon and Fischer (American Mineralogist, Vol. 101, pp. 2288–2300, 2016).

[0046] The calculation method of Shannon and Fischer involves crystals; however, it can also be transferred to glasses if done as follows: (1) Start with the components given in the constituent phases. (2) For each phase, calculate the polarizability of a molecular unit according to Shannon and Fischer; here, according to Conradt's method for cation polarizability, use the values ​​obtained from the assumed coordination number in the crystal, but when calculating the polarizability of oxygen ions with respect to molecular volume (which is necessary), use the values ​​obtained from the glass density of states; where the polarizability values ​​of the constituent phases are listed in the table below. (3) By using the polarizability α of the constituent phases... i Multiply by the corresponding molar number ci The polarizability α of the glass's molecular units is calculated by summing the results.

[0047]

[0048] (4) Through molar volume V mol (Standard unit: cm) 3 Divide by Avogadro's number 6.023 * 10 23 To calculate the molecular volume V m (standard units) ).

[0049]

[0050] (5) Calculate the refractive index n based on the above Shannon and Fischer results. D .

[0051]

[0052] The polarizability of the constituent phases is listed in the table below.

[0053] Table 4. Polarizability of phases with normalized composition

[0054] Composition phase Chemical formula (normalized relative to a single oxide) <![CDATA[α i ]]> Lanthanum titanate <![CDATA[(2La2O3·9TiO2) / 11]]> 9.119538223 Lanthanum niobate <![CDATA[(La2O3·Nb2O5) / 2]]> 16.39292835 Lanthanum molybdenum borate <![CDATA[(La2O3·2MoO3·B2O3) / 4]]> 8.874347232 Lanthanum borate <![CDATA[(La2O3·B2O3) / 2]]> 8.98974281 Yttrium borate <![CDATA[(Y2O3·B2O3) / 2]]> 7.558043681 gadolinium borate <![CDATA[(Gd2O3·B2O3) / 2]]> 8.376326033 Zirconium silicate <![CDATA[(ZrO2·SiO2) / 2]]> 5.193896624 Boron trioxide <![CDATA[B2O3]]> 5.075206993 silicon dioxide <![CDATA[SiO2]]> 3.533771705

[0055] Data on the cation coordination number required to calculate the polarizability of the constituent phases can be found in: J. Phys. Chem. Solids, Vol. 56, No. 10, pp. 1297-1303, 1995 (2La₂O₃·9TiO₂); RSC Adv., 2017, 7, 16777 (La₂O₃·Nb₂O₅); Dalton Trans., 2008, 3709–3714 (La₂O₃·2MoO₃·B₂O₃); Acta Cryst. (2006), E62, i10⁻³–i10⁻⁵ (La₂O₃·B₂O₃); Solid State Sciences 10 (2008) 1173-1178 (Y2O3·B2O3); J.Am.Ceram.Soc., 95[2]696–704 (2012) (Gd2O3·B2O3); The American Mineralogist, Vol. 56, 782-790, May–June (1971) (ZrO2·SiO2); Acta Cryst. (1970), B26, 906-915 (B2O3); J.Appl.Cryst. (1988), 21, 182-191 (SiO2).

[0056] The refractive index n of the glass of the present invention is calculated according to formula (4). D Preferably, it is at least 2.00, for example, at least 2.01, at least 2.02, at least 2.03, at least 2.04, at least 2.05, at least 2.06, at least 2.07, at least 2.08, at least 2.09, at least 2.10, for example, at least 2.11, at least 2.12, at least 2.13, at least 2.14, at least 2.15, at least 2.16, at least 2.17, at least 2.18, at least 2.19, at least 2.20, at least 2.21, at least 2.22, at least 2.23, or at least 2.24. The refractive index n is calculated according to formula (4). D Specifically, it can be less than 2.30, for example, at most 2.29, at most 2.28, at most 2.27, at most 2.26, or at most 2.25. The refractive index n of the glass of the present invention is calculated according to formula (4). D It can be within, for example, the following ranges: 2.00 to 2.30, 2.01 to 2.30, 2.02 to 2.30, 2.03 to 2.30, 2.04 to 2.30, 2.05 to 2.30, 2.06 to 2.30, 2.07 to 2.30, 2.08 to 2.30, 2.09 to 2.30, or 2.10 to 2.30, especially within the following range: 2.11 2.30, 2.12 to 2.30, 2.13 to 2.29, 2.14 to 2.29, 2.15 to 2.28, 2.16 to 2.28, 2.17 to 2.28, 2.18 to 2.27, 2.19 to 2.27, 2.20 to 2.26, 2.21 to 2.26, 2.22 to 2.25, 2.23 to 2.25, or 2.24 to 2.25. Detailed Implementation

[0057] Selection of suitable constituent phases

[0058] Choosing the proportion of the phase according to the invention results in a glass with a high refractive index and a relatively low density. Specifically, the density calculated according to formula (1) and the refractive index n calculated according to formula (4) are... D The preferred quotient is at most 2.50 g / cm³. 3 More preferably up to 2.45 g / cm³ 3 Further optimization to a maximum of 2.40 g / cm³ 3 For example, at most 2.35 g / cm³ 3 At most 2.30 g / cm³ 3 At most 2.25g / cm 3 At most 2.20 g / cm³ 3 Or at most 2.15g / cm 3 The density calculated according to formula (1) and the refractive index n calculated according to formula (4) are...D The quantity can be specifically defined as at least 2.00 g / cm³. 3 For example, at least 2.05 g / cm³ 3 Or at least 2.10 g / cm 3 The density calculated according to formula (1) and the refractive index n calculated according to formula (4) are... D The quantity can be, for example, within the following range: 2.00 g / cm³ 3 Up to 2.50 g / cm 3 Especially 2.00g / cm 3 Up to 2.45 g / cm 3 2.00g / cm 3 Up to 2.40 g / cm 3 2.05g / cm 3 Up to 2.35 g / cm 3 2.05g / cm 3 Up to 2.30 g / cm 3 2.10 g / cm 3 Up to 2.25 g / cm 3 2.15g / cm 3 Up to 2.20 g / cm 3 Or 2.10 g / cm 3 Up to 2.15 g / cm 3 .

[0059] Lanthanum titanate

[0060] The base glass present as a constituent phase in the glass of this invention is lanthanum titanate glass.

[0061] The lanthanum titanate content is in the range of 20 to 80 mol%, for example, in the range of 20 to 70 mol%, 20 to 60 mol%, 25 to 55 mol%, 30 to 50 mol%, or 35 to 45 mol%.

[0062] The share of lanthanum titanate may be, for example, at least 20 mol%, at least 25 mol%, at least 30 mol%, at least 35 mol%, or at least 40 mol%. The share of lanthanum titanate may be, for example, at most 80 mol%, at most 70 mol%, at most 60 mol%, at most 55 mol%, at most 50 mol%, or at most 45 mol%.

[0063] According to the present invention, one mole of lanthanum titanate refers to one mole of (2La2O3·9TiO2) / 11.

[0064] Lanthanum niobate

[0065] The lanthanum niobate content is in the range of 10 to 50 mol%, for example, in the range of 15 to 45 mol%, 20 to 40 mol%, or 25 to 35 mol%.

[0066] The share of lanthanum niobate may be, for example, at least 10 mol%, at least 15 mol%, at least 20 mol%, or at least 25 mol%. For example, the share of lanthanum niobate may be at most 50 mol%, at most 45 mol%, at most 40 mol%, or at most 35 mol%.

[0067] According to the present invention, one mole of lanthanum niobate refers to one mole of (La2O3·Nb2O5) / 2.

[0068] Preferably, the ratio of lanthanum titanate to lanthanum niobate is within the following ranges: 0.5:1 to 8:1, for example 0.7:1 to 7.5:1, 0.8:1 to 7:1, 0.9:1 to 6.5:1, 1:1 to 6:1, >1:1 to 5.5:1, 1.1:1 to 5:1, 1.2:1 to 4.5:1, 1.5:1 to 4:1, 1.75:1 to 3.5:1, or 2:1 to 3:1. The ratio of lanthanum titanate to lanthanum niobate can be, for example, at least 0.5:1, at least 0.7:1, at least 0.8:1, at least 0.9:1, at least 1:1, greater than 1:1, at least 1.1:1, at least 1.2:1, at least 1.5:1, at least 1.75:1, or at least 2:1. The ratio of lanthanum titanate to lanthanum niobate is, for example, up to 8:1, up to 7.5:1, up to 7:1, up to 6.5:1, up to 6:1, up to 5.5:1, up to 5:1, up to 4.5:1, up to 4:1, up to 3.5:1 or up to 3:1.

[0069] The sum of the proportions of lanthanum titanate and lanthanum niobate is preferably at least 50 mol%, at least 55 mol%, or at least 60 mol%. Preferably, the sum of the proportions of lanthanum titanate and lanthanum niobate is in the range of 50 to 90 mol%, for example, 55 to 85 mol% or 60 to 80 mol%. The sum of the proportions of lanthanum titanate and lanthanum niobate may, for example, be at most 90 mol%, at most 85 mol%, or at most 80 mol%.

[0070] Lanthanum molybdenum borate

[0071] The proportion of lanthanum molybdenum borate ranges from 0 to 60 mol%. Therefore, the glass of the present invention can be free of lanthanum molybdenum borate. Specifically, the proportion of lanthanum molybdenum borate can be in the following ranges: 0 to 20 mol%, for example 0 to 15 mol%, 0 to 10 mol%, 0 to 5 mol%, 0 to 2 mol%, or 0 to 1 mol%.

[0072] The share of lanthanum molybdate borate is, for example, up to 60 mol%, up to 20 mol%, up to 15 mol%, up to 10 mol%, up to 5 mol%, up to 2 mol%, or up to 1 mol%. In embodiments of the invention, the share of lanthanum molybdenum borate may also be, for example, at least 1 mol%, at least 2 mol%, at least 4 mol%, or at least 10 mol%.

[0073] According to the present invention, one mole of lanthanum molybdenum borate refers to one mole of (La2O3·2MoO3·B2O3) / 4.

[0074] Lanthanum borate

[0075] The lanthanum borate content is in the range of 2 to 40 mol%, for example, in the range of 3 to 30 mol%, 4 to 20 mol%, or 5 to 15 mol%.

[0076] The share of lanthanum borate may be, for example, at least 2 mol%, at least 3 mol%, at least 4 mol%, or at least 5 mol%. The share of lanthanum borate may be, for example, at most 40 mol%, at most 30 mol%, at most 20 mol%, or at most 15 mol%.

[0077] According to the present invention, one mole of lanthanum borate refers to one mole of (La2O3·B2O3) / 2.

[0078] Yttrium borate

[0079] The yttrium borate content is in the range of 2 to 40 mol%, for example, in the range of 3 to 30 mol%, 4 to 20 mol%, or 5 to 15 mol%.

[0080] The proportion of yttrium borate may be, for example, at least 2 mol%, at least 3 mol%, at least 4 mol%, or at least 5 mol%. The proportion of yttrium borate may be, for example, at most 40 mol%, at most 30 mol%, at most 20 mol%, or at most 15 mol%.

[0081] According to the present invention, one mole of yttrium borate refers to one mole of (Y₂O₃·B₂O₃) / 2.

[0082] gadolinium borate

[0083] The gadolinium borate content ranges from 0 to 40 mol%. Therefore, the glass of the present invention can be gadolinium-free. Specifically, the gadolinium borate content can be in the following ranges: 0 to 20 mol%, for example, 0 to 15 mol%, 0 to 10 mol%, 0 to 5 mol%, 0 to 2 mol%, or 0 to 1 mol%.

[0084] The proportion of gadolinium borate is, for example, up to 40 mol%, up to 20 mol%, up to 15 mol%, up to 10 mol%, up to 5 mol%, up to 2 mol%, or up to 1 mol%. In embodiments of the invention, the proportion of gadolinium borate may also be, for example, at least 1 mol%, at least 2 mol%, at least 4 mol%, or at least 10 mol%.

[0085] According to the present invention, one mole of gadolinium borate refers to one mole of (Gd2O3·B2O3) / 2.

[0086] Zirconium silicate

[0087] The fraction of zirconium silicate is in the range of 2 to 40 mol%, for example, in the range of 3 to 30 mol%, 4 to 20 mol%, or 5 to 15 mol%.

[0088] The share of zirconium silicate may be, for example, at least 2 mol%, at least 3 mol%, at least 4 mol%, or at least 5 mol%. The share of zirconium silicate may be, for example, at most 40 mol%, at most 30 mol%, at most 20 mol%, or at most 15 mol%.

[0089] According to the present invention, one mole of zirconium silicate refers to one mole of (ZrO2·SiO2) / 2.

[0090] Boron trioxide and silicon dioxide

[0091] It may also provide shares of base glass made of boron trioxide and / or base glass made of silicon dioxide.

[0092] The proportion of boron trioxide in the base glass is in the range of 2 to 40 mol%, for example, in the range of 3 to 30 mol%, 4 to 20 mol%, or 5 to 15 mol%.

[0093] The proportion of boron trioxide in the base glass can be, for example, at least 2 mol%, at least 3 mol%, at least 4 mol%, or at least 5 mol%. The proportion of boron trioxide in the base glass can also be, for example, at most 40 mol%, at most 30 mol%, at most 20 mol%, or at most 15 mol%.

[0094] The proportion of silica in the base glass is in the range of 0 to 20 mol%. Therefore, the glass of the present invention may be free of silica as a base glass. Specifically, the proportion of silica in the base glass may be in the range of 0 to 15 mol%, 0 to 10 mol%, 0 to 5 mol%, 0 to 2 mol%, or 0 to 1 mol%.

[0095] The proportion of silicon dioxide in the base glass is, for example, up to 20 mol%, up to 15 mol%, up to 10 mol%, up to 5 mol%, up to 2 mol%, or up to 1 mol%. In embodiments of the invention, the proportion of silicon dioxide in the base glass may also be, for example, at least 1 mol%, at least 2 mol%, or at least 4 mol%.

[0096] Preferably, the proportion of silicon dioxide in the base glass is lower than the proportion of boron trioxide in the base glass. Therefore, the ratio of silicon dioxide to boron trioxide is preferably in the range of 0 to <1.

[0097] The sum of the proportions of boron trioxide and silicon dioxide in the base glass is preferably within the following ranges: 2 to 30 mol%, particularly 3 to 25 mol%, for example 4 to 20 mol% or 5 to 15 mol%. The sum of the proportions of boron trioxide and silicon dioxide in the base glass can be, for example, at least 2 mol%, at least 3 mol%, at least 4 mol%, or at least 5 mol%. The sum of the proportions of boron trioxide and silicon dioxide in the base glass can be, for example, at most 30 mol%, at most 25 mol%, at most 20 mol%, or at most 15 mol%.

[0098] Other ingredients

[0099] In addition to the components already mentioned, the glass may also contain other components, referred to herein as the "balance". The balance of the glass according to the invention is preferably at most 3 mol%, so as not to impair the glass properties adjusted through careful selection of a suitable base glass. In a particularly preferred embodiment, the balance in the glass is at most 2 mol%, more preferably at most 1 mol% or at most 0.5 mol%. The balance specifically contains oxides not present in the base glass mentioned herein. Therefore, specifically, the balance does not contain La₂O₃, Y₂O₃, Gd₂O₃, ZrO₂, TiO₂, Nb₂O₅, MoO₃, B₂O₃, or SiO₂.

[0100] When this specification states that the glass does not contain a certain component or phase, or that it does not contain a specific component or phase, this means that the component or phase is only permitted to exist in the glass as an impurity. This means that the component is added in a non-significant amount. According to the invention, a non-significant amount is less than 1000 ppm (moles) or less than 300 ppm (moles), preferably less than 100 ppm (moles), particularly preferably less than 50 ppm (moles), and most preferably less than 10 ppm (moles).

[0101] Regarding toxicity, the glass is preferably free of CdO and ThO2. The glass is preferably free of Yb2O3, because lighter La2O3 and Gd2O3 compounds are preferred in terms of density. Preferably, the glass is free of Ta2O5 and WO3, because lighter Nb2O5 and MoO3 compounds are preferred in terms of density. The glass is preferably free of alkali metal and / or alkaline earth metal oxides, because the objective of this invention is to pack as many oxygen atoms as densely as possible, so alkali metal and / or alkaline earth metal oxides are not desirable, and compounds according to the invention with higher valence cations are preferred. Rb2O and Cs2O are exceptions. Due to their high coordination numbers, they interfere with the regular structure of oxygen atoms arranged primarily in octahedral or tetrahedral configurations because they follow Pauling's packing rules, and therefore they eliminate the tendency of the glass to crystallize.

[0102] In particular, the glass may contain at least 0.5 mol%, more preferably at least 0.6 mol%, at least 0.7 mol%, at least 0.8 mol%, at least 0.9 mol%, or at least 1 mol% of Rb₂O. Here, Rb₂O is preferred over Cs₂O due to its more favorable effect on transmittance. However, in terms of associated cost, a Cs₂O share of at least 0.5 mol%, such as at least 0.6 mol%, at least 0.7 mol%, at least 0.8 mol%, at least 0.9 mol%, or at least 1 mol%, is also possible. Combinations of the aforementioned Rb₂O and Cs₂O shares are also possible. Therefore, the glass may contain Rb₂O and / or Cs₂O. The sum of the Rb₂O and Cs₂O shares may, for example, be in the range of 0.5 to 3.0 mol%, particularly 1.0 to 2.0 mol%. The sum of the Rb₂O and Cs₂O shares may, for example, be at least 0.5 mol% or at least 1 mol%. The sum of the Rb2O and Cs2O shares can be, for example, up to 3.0 mol% or up to 2.0 mol%.

[0103] Preferred glass components

[0104] In the context of the aforementioned basic system, preferred embodiments stem from providing the desired combination of high refractive index and low density. Specifically, this can be achieved through a suitable combination of individual phase proportions.

[0105] The particularly preferred components are characterized by the following compositional phases of the glass:

[0106] Table 5

[0107] Composition phase Minimum (mol%) Maximum (molar percentage) Lanthanum titanate 20 60 Lanthanum niobate 20 40 Lanthanum molybdenum borate 0 20 Lanthanum borate 4 20 Yttrium borate 4 20 gadolinium borate 0 20 Zirconium silicate 4 20 Boron trioxide 4 20 silicon dioxide 0 10

[0108] Production

[0109] The present invention also relates to a method for producing the glass of the present invention, comprising the following steps:

[0110] - Molten glass raw materials;

[0111] -Optionally formed from molten glass, particularly ingots or flat glass; and

[0112] - Cool the glass.

[0113] Glass forming can include a drawing process. Cooling can be achieved through active cooling using a heat dissipation device or through passive cooling.

[0114] In particular, to suppress undesirable redox reactions, for example, sulfate feedstocks can be used, which can be refined with sulfates, and / or the melt can be foamed with oxygen.

[0115] Uses and glass products

[0116] In addition to glass, the present invention also relates to glass articles formed from glass, such as thin glass with a thickness ≤0.5 mm, preferably ≤0.3 mm, and / or a width of at least 150 mm, preferably at least 200 mm, and more preferably at least 300 mm. The thickness may be, for example, at least 25 μm or at least 50 μm.

[0117] The present invention also relates to the use of the glass according to the invention, particularly as optical glass, as a lens in crop lenses, as an AR lens, as a wafer, as a field wafer-level optics, as a lens, for example a spherical lens, in optical wafer applications, as an optical waveguide, and / or in classical optics.

[0118] Example

[0119] Examples of implementation methods can be found in the table below.

[0120] Table 6

[0121] 1 2 3 4 5 6 Composition phase mole% mole% mole% mole% mole% mole% Lanthanum titanate 44 60 44 44 44 44 Lanthanum niobate 30 20 20 20 20 20 Lanthanum molybdenum borate 0 0 12 12 8 4 Lanthanum borate 4 4 4 4 4 4 Yttrium borate 4 4 4 4 4 4 gadolinium borate 4 4 4 4 4 4 Zirconium silicate 4 4 4 4 8 12 Boron trioxide 6 4 8 4 4 4 silicon dioxide 4 0 0 4 4 4 Calculated density 5.09 5.12 4.93 4.99 4.97 4.95 Calculated BZ 2.14 2.20 2.10 2.11 2.11 2.11

[0122] Table 7

[0123] 7 8 9 10 11 12 Composition phase mole% mole% mole% mole% mole% mole% Lanthanum titanate 39 36 38 38 32 32 Lanthanum niobate 27 24 26 26 36 36 Lanthanum molybdenum borate 0 0 0 0 0 0 Lanthanum borate 20 16 2 12 6 6 Yttrium borate 5 4 2 2 2 2 gadolinium borate 0 0 8 8 8 8 Zirconium silicate 4 16 16 6 6 6 Boron trioxide 5 4 6 6 6 8 silicon dioxide 0 0 2 2 4 2 Calculated density 5.18 5.09 5.04 5.14 5.20 5.17 Calculated BZ 2.12 2.11 2.11 2.10 2.11 2.11

[0124] Table 8

[0125] 13 14 15 16 17 18 Composition phase mole% mole% mole% mole% mole% mole% Lanthanum titanate 40 36 30 28 26 26 Lanthanum niobate 30 30 30 34 36 36 Lanthanum molybdenum borate 0 0 0 0 0 0 Lanthanum borate 6 6 16 10 2 2 Yttrium borate 2 6 16 18 28 30 gadolinium borate 6 12 2 2 2 0 Zirconium silicate 2 2 2 2 2 2 Boron trioxide 6 4 2 2 2 2 silicon dioxide 8 4 2 4 2 2 Calculated density 5.05 5.24 5.23 5.21 5.20 5.17 Calculated BZ 2.11 2.11 2.10 2.10 2.10 2.10

[0126] Table 9

[0127] 19 20 21 22 23 24 Composition phase mole% mole% mole% mole% mole% mole% Lanthanum titanate 70 60 50 76 66 56 Lanthanum niobate 10 20 30 10 20 30 Lanthanum molybdenum borate 0 0 0 0 0 0 Lanthanum borate 2 2 2 2 2 2 Yttrium borate 2 2 2 2 2 2 gadolinium borate 0 0 0 0 0 0 Zirconium silicate 2 2 2 2 2 2 Boron trioxide 12 12 12 6 6 6 silicon dioxide 0 0 0 0 0 0 Calculated density 4.61 4.79 4.94 4.86 5.02 5.16 Calculated BZ 2.17 2.16 2.16 2.25 2.23 2.22

[0128] Table 10

[0129] 25 26 27 28 29 30 Composition phase mole% mole% mole% mole% mole% mole% Lanthanum titanate 66 56 46 50 60 70 Lanthanum niobate 12 22 32 32 22 12 Lanthanum molybdenum borate 0 0 0 0 0 0 Lanthanum borate 4 4 4 4 4 4 Yttrium borate 4 4 4 4 4 4 gadolinium borate 0 0 0 0 0 0 Zirconium silicate 4 4 4 4 4 4 Boron trioxide 6 6 6 4 4 4 silicon dioxide 4 4 4 2 2 2 Calculated density 4.78 4.94 5.07 5.19 5.06 4.91 Calculated BZ 2.17 2.17 2.16 2.20 2.21 2.22

Claims

1. A glass, wherein the composition of the glass is characterized by the following constituent phases: in, According to the formula Calculated refractive index n D The value is at least 2.05, where α is the polarizability of the molecular unit of the glass, and V m The value is the molecular volume.

2. The glass according to claim 1, wherein, The proportion of lanthanum niobate is at least 15 moles.

3. The glass according to claim 1 or 2, wherein the composition of the glass is characterized by the following constituent phases:

4. The glass according to claim 1 or 2, wherein, The ratio of the lanthanum titanate to the lanthanum niobate is at least 0.7:

1.

5. The glass according to claim 1 or 2, wherein, The total percentage of boron trioxide and silicon dioxide is in the range of 4 to 20 mol%.

6. The glass according to claim 1 or 2, wherein, According to the formula The calculated density of the glass is less than 5.30 g / cm³. 3 M i The molar mass of each constituent phase, The density of each constituent phase, c i The molar ratio of each constituent phase.

7. The glass according to claim 1 or 2, wherein, The total proportion of lanthanum titanate and lanthanum niobate is at least 50 moles.

8. The glass according to claim 6, wherein, According to the formula The calculated density is consistent with the formula The calculated refractive index n D The quotient is at most 2.50 g / cm³. 3 .

9. The glass according to claim 1 or 2, wherein, The ratio of the silicon dioxide content to the boron trioxide content is less than 1.

10. The glass according to claim 1 or 2, wherein, The glass may contain other components referred to as the balance, wherein the balance comprises at most 3 moles.

11. The glass according to claim 1 or 2, wherein, According to the formula The calculated refractive index n D It should be at least 2.

10.

12. Use of a glass according to any one of claims 1 to 11, wherein the glass is used as optical glass, as a wafer, in field wafer-level optics, as an optical waveguide, and / or in classical optics.

13. Use of a glass according to any one of claims 1 to 11, wherein the glass is used as a lens, in an AR lens, and / or in an optical wafer application.

14. Use of a glass according to any one of claims 1 to 11, wherein the glass is used as a lens in a crop lens and / or as a spherical lens.

15. A glass article comprising the glass according to any one of claims 1 to 11, wherein the thickness of the glass is at most 0.5 mm.

16. A method for producing glass according to any one of claims 1 to 11, comprising the following steps: - Molten glass raw materials; and - Cool the glass.

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