Continuous production of photosensitive glass bodies

Abstract

Method for producing a photosensitive glass body comprising the steps a. Providing a mixture of raw materials for the desired glass, b. Melting of the mixture, c. Transferring the molten metal into a mold, d. Pressing the glass in the mold to form the glass body, wherein the melt has a temperature above 1,000°C at the time of transfer to the mold, wherein the melt is cooled in the mold such that the temperature range of 990°C to 600°C is traversed within a period of less than 15 minutes, and wherein the glass Si 4+ , has at least one crystal agonist, at least one crystal antagonist and at least one nucleation pair, - where the Crystal Agonists are selected from Na + , K + , and Li + , - where the crystal antagonists are selected from Al 3+ , B3+ , Zn 2+ , Sn 2+ and Sb 3+ , - wherein the nucleating pair contains cerium and at least one representative from the group silver, gold and copper, and whereby the molar fraction of crystal agonists in Cat% in relation to the molar fraction of Si 4+ at least 0.3 and at most 0.85, wherein the glass is subsequently subjected to a sensitization step following step b. and / or c., which corresponds to cooling from a temperature T1 to a temperature T2 with an average cooling rate K of 10°C / h to 200°C / h, wherein the temperature T1 is at least above the glass transition temperature T G of the glass and the temperature T2 is at least 150°C below T1.

Description

[0001] The present invention relates to a process for the continuous production of photosensitive glass bodies. The glass bodies consist of photostructurable glass.

[0002] Continuous manufacturing processes for glass bodies are known to those skilled in the art. They are suitable for continuously producing pressed glass bodies from a glass melt by pouring the melt into a mold, which can be used for various applications.

[0003] During pressing, molten glass is poured into a mold, usually made of metal. Depending on the size of the mold, the glass cools at different rates in the mold. This process can lead to crystallization in glass susceptible to crystallization, especially if the cooling of the glass takes too long, which is particularly problematic for relatively large geometries. Crystallization renders the glass unusable. Consequently, continuous pressing processes have so far only been used for technical glasses that are not particularly susceptible to crystallization and for particularly crystallization-resistant optical glasses.

[0004] A distinction must be made between the unintentional crystallization during glass production described above, which is also referred to as "devitrification," and the deliberate crystal formation that can be achieved in photostructurable glasses through exposure and annealing. While both are crystallization processes, they differ in the crystals that form. While alkali disilicates are formed during devitrification, alkali metasilicate crystals are produced during deliberate crystallization in photostructurable glasses. Despite the aforementioned differences with regard to the processes underlying crystallization, photostructurable glasses exhibit, in addition to the tendency toward crystal formation induced by exposure and annealing, which is desirable for photostructurability, also an increased tendency toward devitrification.

[0005] Photostructurable glasses are generally characterized by a pronounced crystallization tendency, which is desirable for structuring. For example, these glasses contain nucleating agents that form metal nuclei after targeted UV irradiation of specific areas of a glass body. The following reaction equation illustrates this process using silver as a nucleating agent. Ce 3+ + Ag + + hv → Ce 4+ + Ag 0 (Equation I)

[0006] By irradiating the photosensitive glass with UV light at a wavelength of approximately 320 nm, the trivalent cerium donates an electron to the silver ion, forming elemental silver. The desired crystal nuclei form around the resulting atomic silver in a subsequent annealing step.

[0007] It is a challenge for the manufacturer of photosensitive glass to strike a good balance between the desired crystallizability after production and the critical tendency to crystallize, which complicates production. For example, increasing the amount of silver used leads to the formation of elemental silver during the melting process. This precipitates and can lead to the formation of silver bubbles or droplets, making production difficult or even impossible.

[0008] Furthermore, the production of photo-structurable glass is particularly challenging because the components cerium and silver must each be present in the correct oxidation state in the finished glass for the reaction shown above (Equation I) to occur. Of course, an oxidizing melt process prevents the precipitation of silver during the melting process, as reduction to metallic silver is prevented. However, in such a case, the cerium is present in the tetravalent form in the glass, so the desired reaction (Equation I) cannot occur upon UV exposure.

[0009] If, however, a reducing melting process is chosen to increase the proportion of trivalent cerium, the risk of elemental silver forming during production increases. Silver nuclei in the unexposed glass interfere with the selective crystallization of the glass during annealing, because unexposed areas would also crystallize. Furthermore, the glass would not meet the transmission requirements. Rather, it is desirable that no elemental silver be formed during production, so that essentially all of the silver in the glass is available as monovalent silver ions for reaction I.

[0010] In addition to the nucleating agent pair, which usually only makes up a very small proportion of the glass, the rest of the glass's composition also contributes to its susceptibility to crystallization. The focus of developers of such glasses has so far been on increasing the crystallization tendency to a level necessary for subsequent structuring. Therefore, processing photo-structurable glasses in continuous pressing processes has not been considered to date.

[0011] DE 10 2005 003 594 A1 describes methods for manufacturing optical components, as well as devices comprising such components. The focus here is primarily on the production of a first and a second optical element and the joining of the two elements. A continuous molding process is not described.

[0012] WO 2015 / 019989 A1 describes manufacturing processes for photosensitive glasses with various melting and cooling steps. A continuous pressing process is not described.

[0013] However, it would be desirable to have a glass that can be produced through a continuous pressing process. The resulting glass body could then be exposed and structured.

[0014] It is therefore the object of the present invention to provide a method by which a photostructurable glass body can be produced in a continuous pressing process without having inferior properties with regard to crystallization ability and photosensitivity than the glasses of the prior art.

[0015] This object is achieved according to the invention by, on the one hand, selecting a glass which can be processed in such a way and, on the other hand, by adapting the pressing process to the glass as defined in the patent claims.

[0016] The method according to the invention for producing a photosensitive glass body comprises the steps a. Providing a mixture of raw materials for the desired glass, b. Melting the mixture, c. Transferring the melt into a mold, d. Pressing the glass in the press mold to form the glass body, wherein the melt has a temperature above 1,000°C at the time of transfer into the press mold, wherein the melt is cooled in the press mold in such a way that the temperature range from 990°C to 600°C is passed through in a period of less than 15 minutes, and wherein the glass Si 4+, at least one crystal agonist, at least one crystal antagonist and at least one nucleating pair, - wherein the crystal agonists are selected from Na + , K + , and Li + , - wherein the crystal antagonists are selected from Al 3+ , B 3+ , Zn 2+ , Sn 2+ and Sb 3+ , - wherein the nucleating pair contains cerium and at least one member from the group silver, gold and copper, and where the molar fraction of crystal agonists in cat.% in relation to the molar fraction of Si 4+ at least 0.3 and at most 0.85, wherein the glass is subjected to a sensitization step following step b. and / or c., which corresponds to cooling from a temperature T1 to a temperature T2 with an average cooling rate K of 10°C / h to 200°C / h, wherein the temperature T1 is at least above the glass transition temperature T G of the glass and the temperature T2 is at least 150°C below T1.

[0017] Following melting and / or transfer, the glass is subjected to a sensitization step which corresponds to cooling from a temperature T1 to a temperature T2 with an average cooling rate K of 10°C / h to 200°C / h, wherein the temperature T1 is at least above the glass transition temperature T G of the glass and the temperature T2 is at least 150°C below T1. In a particularly preferred embodiment, T1 is 100°C above the glass transition temperature T Gof the glass and temperature T2 is 250°C below T1. In another preferred embodiment, T1 is 50°C above the glass transition temperature T G of the glass and temperature T2 is 200°C below T1. In another preferred embodiment, T1 is 25°C above the glass transition temperature T G of the glass and temperature T2 is 150°C below T1.

[0018] Preferably, the cooling from temperature T1 to temperature T2 takes place continuously. "Continuously" in this context means that the glass is cooled continuously from T1 to T2 without being held at specific temperature levels. In particular, this refers to cooling at a substantially constant cooling rate. Preferably, the maximum and minimum cooling rates during cooling from temperature T1 to temperature T2 deviate from the average cooling rate K by at most ± 20%, more preferably by at most ± 15%, more preferably by at most ± 10%, more preferably by at most ± 5%.

[0019] The invention also relates to a glass body made of sensitized, photostructurable glass which 4+ , one or more crystal agonists, one or more crystal antagonists and at least one pair of nucleating agents, a. wherein the crystal agonists are selected from Na + , K + and Li +, b. wherein the crystal antagonists are selected from Al 3+ , B 3+ , Zn 2+ , Sn 2+ and Sb 3+ , c. wherein the nucleating agent pair contains cerium and at least one member from the group silver, gold and copper, wherein the molar proportion of the crystal agonists in cat.% in relation to the molar proportion of Si 4+ at least 0.3 and at most 0.85, and the glass has a cooling state which corresponds to a continuous cooling from a temperature T1 to a temperature T2 with a cooling rate K of 10°C / h to 200°C / h, wherein the temperature T1 is at least above the glass transition temperature T Gof the glass and the temperature T2 is at least 150°C below T1. "Continuous" means that cooling occurs continuously from T1 to T2 without the glass being held at specific temperature levels. In particular, this refers to cooling at a substantially constant cooling rate. If cooling to room temperature is continued after cooling to T2, this further cooling can also occur continuously; however, further cooling below T2 is not critical. Room temperature is preferably 20°C.

[0020] The cooling state of a glass can be determined for a given glass even without knowledge of the manufacturing conditions. Given a glass sample P, its refractive index η dand / or their mass density ρ. The sample is then preferably divided into several individual samples P1, P2, P3, etc. Each sample is heated to temperature T1 and then cooled to temperature T2 at different cooling rates K1, K2, K3, etc. After cooling to temperature T2 and preferably further cooling to room temperature, the refractive index η d and / or the mass density ρ, so that a cooling rate can be assigned to each of the values. The obtained pairs of values ​​can then be plotted in a coordinate system, where the ordinate represents the density values ​​and the abscissa the cooling rate. Based on the cooling curve thus obtained, a conclusion can be drawn from the density of the glass sample P to its cooling state. The relationship between cooling rate and refractive index is shown for an example glass in Fig.shown. If the x-axis is plotted logarithmically, the relationship results from a simple straight line equation. An example of this is shown in Fig. shown.

[0021] The terms refractive index and refractive power are used synonymously in this description.

[0022] The cooling state of a glass is therefore a measure of the conditions during cooling of the glass. A conventionally "quenched" glass that was cooled very quickly after melting (e.g., >300°C / h) exhibits a high cooling state. The ions in such a glass are "frozen" in a relatively disordered state. By rapidly cooling from the melt, the glass is thus "frozen" at a high energy level. The high temperature ranges in which a spatial approximation of the crystal components (crystal agonists, Si 4+) was still possible due to low viscosity, were carried out quickly. As a result, a quickly cooled glass that is at a high cooling state has a comparatively low density or refractive index. The differences in the refractive index of a glass depending on its cooling state are comparatively small. However, since these properties can be reliably measured up to the sixth decimal place, this method is still suitable for delivering a reliable measurement result. Tests have shown that the sensitization of the glass described here causes an increase in the refractive index at least to the fifth, and preferably even to the fourth, decimal place.

[0023] The cooling state according to the invention is preferably achieved by subjecting the glasses of this invention to a sensitization step described herein. This sensitization step is described further below. Whenever sensitization is mentioned herein, this always refers to a processing step that takes place before the glass is exposed to light. The heat treatment step after the glass is exposed to light is referred to herein as "annealing" in accordance with the specialist literature.

[0024] The inventors believe that there are several reasons for the improved crystallizability of the sensitized glass bodies according to the invention, resulting from the complex interplay of glass composition and sensitization or manufacturing process. It is likely that the sensitization leads to a convergence of the crystal components in the glass. This convergence could be made possible by the fact that the glass, during cooling from T1 to T2, remains in a viscosity range for a comparatively long period (compared to cooling by quenching) that allows diffusion of the crystal agonists in the network. As a result, the glass approaches the crystalline state without crystallizing. It is thus more sensitive to the desired crystallization after UV irradiation.

[0025] Furthermore, sensitized glass exhibits a tighter glass structure due to its higher density. This could be the reason why particularly small crystals form in the crystallized glass. After all, the crystal agonists, whose mobility is important for crystallization, cannot move as easily through diffusion in a tight-meshed structure as in a comparable, coarser network. This likely hinders crystal growth in the sensitized glass. While crystals can form around the nuclei, their growth, and thus the fusion of several crystals into larger crystals, is prevented. The result is a fine crystal structure that allows for the etching of particularly fine structures.

[0026] Furthermore, it has been shown that sensitization reduces the self-absorption of the glass matrix (band edge) in the important UV range around the absorption maximum of Ce 3+towards shorter wavelengths. This results in lower absorption in this range and allows the UV light used for irradiation to penetrate further into the glass and achieve a deeper structure depth. Fig. The results shown demonstrate the increase in transmission in the UV range achieved by sensitization.

[0027] According to the invention, a glass body is thus cooled at a cooling state corresponding to a comparatively low cooling rate. Prior art glasses are cooled at high cooling rates to reduce the risk of crystallization. The glass bodies according to the invention, in contrast, are cooled by sensitization, either directly from the melt or in a step following the melt and optionally hot processing, to such an extent that a cooling state of at most 200°C / h is achieved. Preferably, the cooling state is even below 150°C / h, more preferably below 120°C / h, particularly preferably below 100°C / h or below 85°C / h. In a preferred embodiment, the cooling state can even be below 80°C / h.

[0028] However, it should be noted that, due to the circumstances described above (ion mobility, crystal formation), depending on the glass composition, a certain cooling state should preferably not be exceeded. Very slow cooling could result in the glass remaining in a temperature range that allows crystal formation for too long. Crystallization would then occur. It has proven advantageous not to fall below a cooling state of 10°C / h, more preferably 20°C / h, particularly preferably 40°C / h, and even more preferably 60°C / h, to avoid the risk of crystallization. This does not preclude the possibility that certain glass compositions may tolerate such a low cooling state.

[0029] The term "cooling state of X°C / h" indicates a cooling state corresponding to cooling from a temperature T1 to a temperature T2 at a constant cooling rate K of at most X°C / h. It should be noted that the specification of a "cooling state corresponding to cooling from a temperature T1 to a temperature T2 at a constant cooling rate K of at most X°C / h" does not mean that the glass or glass body characterized in this way was actually cooled from T1 to T2 at such a constant cooling rate. Rather, it means that the glass or glass body has the same cooling state as such a glass. The glass body according to the invention can also have been cooled from a temperature T1 at a cooling rate K' to a temperature T1' and then at a cooling rate K'' to a temperature T2. The decisive factor is the cooling state obtained, which is specified as defined here to ensure clarity and measurability.

[0030] In the glass body according to the invention, alkali metasilicate crystals are intended to form during annealing after exposure to light. Metasilicates are characterized by a stoichiometry that contains one mole of crystal agonist, e.g., an alkali metal oxide such as Li2O or Na2O, per mole of silicon dioxide (SiO2). Thus, the stoichiometric ratio of alkali metal ions to silicon ions in the metasilicate is 2:1. If the two components, alkali metal oxide and silicon dioxide, were melted and cooled together in this stoichiometric ratio of the crystal, a ceramic would be formed, not a glass.

[0031] In order to obtain a glass and not a ceramic, the invention involves, on the one hand, a significant deviation from the crystal stoichiometry and, on the other hand, the use of crystal antagonists to reduce the crystallization tendency of the glass.

[0032] According to the invention, "glass" is understood to mean a substantially completely amorphous material, and "ceramic" is understood to mean a substantially completely crystalline material. A material containing crystalline and amorphous phases is called "glass-ceramic."

[0033] It has been found to be advantageous to use the stoichiometry of crystal agonists and silicon in the form of Si 4+ to be chosen so that the molar ratio in cat.% of crystal agonists to Si 4+ in the glass is at least 0.3, preferably at least 0.5 and more preferably at least 0.55. However, this ratio should preferably not exceed a value of at most 0.85, more preferably at most 0.7, and a ratio of at most 0.65 is particularly advantageous. 4+If too little crystal agonist is used, the composition deviates too far from the desired stoichiometry, and the crystallization tendency decreases significantly. Crystallizing such a glass would be time-consuming and energy-intensive. Furthermore, disilicates would predominantly form, which, compared to glass, do not exhibit as significant a difference in solubility with respect to conventional etching solutions as the desired metasilicates. Too much crystal agonist, on the other hand, would greatly increase the crystallization tendency due to a close approach to the metasilicate stoichiometry, making processability difficult or impossible.

[0034] A glass melt has a very high temperature, which lies far above the temperature range in which crystals or nuclei can form. The glass used according to the invention for the glass body is melted, for example, at temperatures that are preferably above 1,300°C, more preferably even above 1,400°C. Such a temperature ensures that all components are melted. However, a temperature of 1,800°C, more preferably 1,700°C and especially preferably 1,600°C should not be exceeded, since excessively high temperatures promote the reduction of silver in the glass and also greatly increase the energy requirement. Only when the glass melt cools after production does the tendency to crystallize increase until the viscosity of the melt is so high that nuclei can no longer form. The reason for this is that with increasing viscosity, the diffusion of the crystal components is restricted.For this reason, glasses susceptible to crystallization must be cooled quickly enough. If cooling is too slow, the thermodynamically favored crystal phase forms, and the result is not glass, but a glass-ceramic. This largely also applies to the glass according to the invention, with the exception that sensitization occurs either by cooling the melt comparatively slowly in the temperature range from T1 to T2, or by first rapidly cooling from the melt and then slowly cooling from T1 to T2 in a subsequent sensitization step.

[0035] By rapidly cooling from the melt, the glass is essentially "frozen" at a high energy level. It is only due to the glass's high viscosity that it does not transform into the energetically more favorable crystalline state. This is also the reason why photosensitive glasses are annealed after irradiation. Otherwise, the temperature required for nucleation ("nucleation temperature") in the irradiated photosensitive glasses would not be reached, nor would the higher "crystal growth temperature." These two temperatures represent temperature ranges. The prior irradiation ensures that the irradiated areas can be specifically crystallized in the annealing step. In conjunction with the increased etchability of the crystallized areas, this enables the targeted introduction of structures in the subsequent etching step.

[0036] Glasses that already have an extremely high tendency to devitrification due to their composition or the processing involved must be cooled very quickly after melting. This increases the viscosity of the melt so rapidly that no crystallization takes place. The result is a glass that is "frozen" at a high cooling state. Such a glass can be well suited for photostructuring due to the relationship described above between the tendency to devitrification and the tendency for crystal formation induced by exposure and tempering. The desired crystals form quickly during tempering after irradiation. However, such a glass can only be post-processed using relatively cost-intensive processes. Most processes that require the glass to be reheated are ruled out from the outset.Ultimately, reheating is no different from tempering: the diffusion of ions, especially small alkali metal ions, increases, and nuclei and crystals form. Consequently, glasses that are inherently particularly susceptible to devitrification can only be cold-processed. Hot-processing (e.g., redrawing) is not an option. The same applies to hot-forming steps directly from the melt (e.g., pressing, floating, rolling, down-drawing, overflow fusion). Glasses with such an extremely high devitrification tendency are not the subject of the present invention.

[0037] The present invention uses glasses that exhibit a pronounced tendency to crystallize, allowing them to be photostructured, but which, on the other hand, do not exhibit an extremely high tendency to devitrification. This is achieved through the process and / or the composition of the glasses. Thus, the glasses deviate relatively significantly from metasilicate stoichiometry, and they are preferably melted in a relatively oxidizing manner.

[0038] This ensures that the nucleating pair present in the glass (e.g. cerium and silver) is predominantly present in the higher oxidation states with respect to the nucleation source (especially Ag). This also results in a higher proportion of cerium in the oxidation state Ce. 4+ than would be the case with a more reducing melt. In the prior art, this constellation is described as undesirable, since as much Ce as possible is required for nucleation according to the reaction described above (equation I).3+ must be present. However, according to the invention, this is intended to give the glass a slightly lower tendency to crystallize directly after melting. According to the invention, the ratio of Ce 3+ to Ce 4+ through raising awareness again more in favor of the Ce 3+ Unfortunately, the ratio of the two oxidation states of cerium cannot be determined in the glass. Decomposition of the glass changes the oxidation state and the transmission bands of the cerium. 4+ are in a wavelength range in which the glass itself absorbs strongly.

[0039] A preferred comparatively oxidizing melting process has the advantage that the glasses can be subjected to one or more hot processing steps directly after melting or at a later time, but in any case before exposure and especially before sensitization. The method according to the invention is such a hot processing step. The nucleating agent pair is, as it were, oxidized at the time of hot processing due to the presence of Ce 4+ limited in its activity. However, without nuclei, no crystals form. The glass or melt is therefore in a relatively uncritical state with regard to crystallization.

[0040] According to the invention, pressing is used as a hot processing step, which preferably takes place before exposure and tempering. This hot processing method is sufficiently known from the prior art. It can be carried out with the glass used here essentially as previously known, but with the proviso that the melt must be cooled relatively quickly through the temperature range from 990°C to 600°C, in particular to 460°C. T1 is preferably below 600°C, so that a rapid passage through the aforementioned temperature range preferably allows for directly subsequent sensitization. In this temperature range, the risk of crystallization is considerable, even for the glass used here. The aforementioned temperature range should therefore be passed through in no more than 15 minutes, more preferably no more than 10 minutes, further preferably no more than 5 minutes, and particularly preferably no more than 3 minutes.

[0041] A key aspect responsible for the pronounced but moderate tendency of the present glass bodies to crystallize is their composition. This invention relies to a large extent on the correct adjustment of the molar ratios of the cations to one another (crystal stoichiometry). Therefore, it is useful to characterize the glass composition in cat. %. Of course, the glass also contains anions, which will be described further below. However, they are less influential on the properties of the glass than the cations, so the core of the invention lies more in the cation composition.

[0042] The term "cation percentage" (abbreviated "cat.%) refers to the relative molar proportions of cations relative to the total amount of cations in the glass. Of course, the glass also contains anions, whose relative molar proportions relative to the total amount of anions in the glass are expressed herein as "anion percentage" (abbreviated "anion-%").

[0043] As explained at the beginning, the glass used in the invention has Si 4+ This component is preferably added to the melt in the form of SiO2 (sand). Si 4+ is essential for the glass properties and crystallization behavior of the glass, as it is a key component of the alkali metasilicate crystal. The stoichiometry of the alkali metasilicate crystal is shown below: R2O3Si R = alkali metal ion

[0044] In a preferred embodiment, the glass comprises silicon (Si 4+) in proportions of at least 45 cat.%, more preferably at least 50 cat.%, more preferably at least 52 cat.% and particularly preferably at least 56 cat.%. The content of this component should not exceed a value of 65 cat.%, more preferably at most 63 cat.%, more preferably at most 61 cat.% and particularly preferably at most 60.5 cat.%. The proportion of this component must be taken into account because too low a proportion of silicon can severely impair the tendency to crystallize. Very small amounts of silicon would even increase the tendency to crystallize to such an extent that no glass is obtained at all. Furthermore, silicon is an important glass former that plays a decisive role in determining the glass network. If, on the other hand, too much silicon is used, the glass network becomes denser overall.This limits the ion mobility in the glass and prevents the diffusion of alkali metal ions in particular, thus preventing crystal formation.

[0045] The selection of the correct amount of silicon is comparatively complex, since not only the proportion of silicon alone is decisive, but also the proportions of Al 3+ and B 3+ and the ratio of alkali metal ions to silicon play a role. According to the invention, the molar ratio of alkali metal ions to the molar proportion of silicon is at least 0.3 to at most 0.85. This ratio should preferably be at least 0.4 and at most 0.8, more preferably at least 0.5 and at most 0.75, and particularly preferably at least 0.6 and at most 0.7.

[0046] Consequently, the proportion of crystal agonists in the glass also plays a role. According to the invention, the crystal agonists are preferably selected from the cations of lithium (Li + ), sodium (Na+ ) and potassium (K + ). The glass particularly preferably contains all three components Li + , N / a + and K + The amount of these components should preferably be at least 30 cat.%, more preferably at least 32 cat.%, and even more preferably at least 34 cat.%. However, a content of 45 cat.%, more preferably 43 cat.%, even more preferably 40 cat.% or 38 cat.% should not be exceeded. Too large a proportion of these components would, on the one hand, greatly increase the tendency of the glass to crystallize and, on the other hand, greatly reduce the chemical resistance of the glass. Too small a quantity of these components would greatly reduce the tendency to crystallize, as this would inherently lead to a greater deviation from the metasilicate stoichiometry.

[0047] However, not only the total content of the crystal agonists is important, but also the content of the respective individual components and their ratio to one another. The glass preferably comprises lithium in a proportion that exceeds the molar proportions of sodium and potassium in each case. Preferably, the lithium content also exceeds the sum of potassium and sodium in the glass. In other words, lithium is preferably the main component among the crystal agonists. The amount of lithium in the glass according to the invention is preferably at least 20 cat.%, more preferably at least 25 cat.%, even more preferably at least 27.5 cat.%, and particularly preferably at least 28 cat.%. The content should preferably be at most 40 cat.%, further preferably at most 35 cat.%, and particularly preferably at most 32 cat.%. The ratio of lithium to silicon should preferably be at least 0.4 and more preferably at least 0.45.In particular, this value is at most 0.7, more preferably at most 0.65, more preferably at most 0.6 and particularly preferably at most 0.55.

[0048] Since lithium is preferably the main component among the crystal agonists, the advantages and disadvantages of the aforementioned ratio of lithium to silicon are the same as those discussed above for the ratio of crystal agonists to silicon. According to the invention, lithium is therefore preferably the main component among the crystal agonists because lithium is particularly mobile, as it is the smallest cation of the alkali metals. This simplifies the diffusion of lithium compared to the other alkali metals and enables the sensitization of the glass to be carried out at comparatively low temperatures and relatively quickly.

[0049] Although lithium is preferably the main component of the crystal agonists in the glass and thus exceeds the molar proportions of the components sodium and potassium, the glass preferably also contains the components potassium and / or sodium in addition to lithium. It is preferred that the potassium component exceeds the sodium component in its molar proportion. It has been shown that this increases the tendency of the glass to form desired metasilicate crystals after exposure to light. Too large an amount of sodium in relation to potassium would promote crystal formation in favor of disilicates. Potassium, when used in small amounts, can improve the chemical resistance of the glass. Furthermore, potassium reduces the tendency of the glass to devitrify during production. The potassium content in the glass should preferably be at least 2 cat.%, more preferably at least 2.5 cat.%, even more preferably at least 3 cat.-% and particularly preferably at least 3.5 cat.%. However, the content of this component should preferably be at most 8 cat.%, further preferably at most 7 cat.%, more preferably at most 6 cat.%, and particularly preferably at most 5 cat.%.

[0050] According to the invention, the sodium component should preferably be present in the glass in a proportion of at least 1 cat.%, more preferably at least 1.5 cat.%, and even more preferably at least 2 cat.%. Preferably, a content of at most 5 cat.%, more preferably at most 4 cat.%, should not be exceeded. In a particularly preferred embodiment, the sodium content in the glass does not exceed 3 cat.%. This ensures that the formation of disilicate is largely prevented.

[0051] As mentioned at the beginning, the glasses contain not only silicon and crystal agonists, but also at least one representative from the group of crystal antagonists. Preferred crystal antagonists according to the invention are aluminum (Al 3+ ), boron (B 3+ ) and zinc (Zn 2+ ) and tin (Sn 2+ ) and antimony (Sb 3+). The crystal antagonists serve to inhibit crystal or nucleation formation. If no crystal antagonists were used at all, the glass would crystallize very quickly. Possibly no glass would be obtained at all. According to the invention, the content of crystal antagonists should preferably be at least 2 cat.%, more preferably at least 2.5 cat.%, particularly preferably at least 3.5 cat.%. In order not to excessively inhibit crystal formation, the content of crystal antagonists is preferably limited to a maximum of 9 cat.%, further preferably a maximum of 8 cat.%, and more preferably a maximum of 7.5 cat.%. In particularly preferred embodiments, the content is limited to a maximum of 5.5 cat.%.

[0052] Among the crystal antagonists, aluminum is preferably the main component, i.e. the aluminum component is present in the glass in a larger proportion, with regard to the molar amounts present, than the other crystal antagonists, in particular than the components boron and zinc. This has the advantage that aluminum, when used in limited proportions, does not hinder the formation of metasilicates. According to the invention, at least 2 cat. %, more preferably at least 3 cat. %, and particularly preferably at least 3.5 cat. % aluminum is used for this purpose. Aluminum reduces the sensitivity to devitrification. However, the amount of aluminum used should not be too high, since this could in turn lead to the formation of spodumene solid solutions. Furthermore, aluminum increases the melting point of the glass, which must be compensated for by using larger amounts of alkali ions.For this reason, the aluminum component should be used in amounts that preferably do not exceed 8 cat.%, more preferably 7 cat.%, further preferably 6 cat.%, and particularly preferably 5 cat.%. In particularly preferred embodiments, the amount of aluminum is limited to a maximum of 4.5 cat.%.

[0053] Since the recommended amount of aluminum is limited due to the risk of forming other crystal phases, it may be necessary to use additional crystal antagonists. Boron and zinc are particularly suitable for this. The invention encompasses the use of glasses that contain only boron or only zinc, as well as those that contain both of these components. It is preferred that the amount of boron is severely limited. This is because boron has a very strong effect on the tendency to crystallize. If too much boron is used, the tendency to crystallize is greatly reduced. For this reason, boron is preferably used in amounts not exceeding 3 cat.%. More preferably, this component should not be used in amounts greater than 1.5 cat.% and particularly preferably not greater than 0.5 cat.%, in particular not greater than 0.35 cat.%. However, a minimum amount of boron may be advisable.According to the invention, this is preferably at least 0.05 cat.%, more preferably at least 0.1 cat.% and particularly preferably 0.2 cat.%.

[0054] In addition to or as an alternative to boron, zinc can serve as a crystal antagonist. If both zinc and boron are used, the amount of zinc should be greater than the amount of boron in terms of the molar proportions of the cations. Preferably, the amount of zinc is at least 1.5 times the molar proportion of boron, but in particular not higher than 2.5 times. In preferred embodiments, the glass comprises zinc in a proportion of at least 0.2 cat.%, more preferably at least 0.3 cat.%, and particularly preferably at least 0.45 cat.%. Zinc prevents the undesired reduction of silver and thus uncontrolled nucleation by removing terminal oxygen in the glass. However, if too much zinc is used, the tendency to crystallize decreases more than desired. Therefore, the amount of zinc should preferably be at most 2.5 cat.%, more preferably at most 1.5 cat.%, and particularly preferably at most 0.8 cat.%.

[0055] In addition to the components mentioned, antimony (Sb 3+ ) and tin (Sn 2+ ). Tin and antimony serve as reducing agents, ensuring a particularly fine distribution of the germ source in the glass. This effect is particularly evident with small amounts of these components. For the tin component, the proportion is preferably below 0.1 cat.%. Preferably, the glass is even tin-free.

[0056] The preferred proportion of antimony in the glass is limited to a maximum of 0.4 cat.%, more preferably a maximum of 0.2 cat.%. The inventors have discovered that, surprisingly, at low proportions of antimony in the glass, the transmission in the UV range is increased. This allows the UV light used for irradiation to penetrate further into the glass, so that a deeper structural depth can be achieved. The antimony content can therefore be used to adjust the level of absorption in the UV range and thus the achievable exposure depth independently of the cerium content. The proportion of antimony in the glass is particularly preferably limited to a maximum of 0.19 cat.%, more preferably to a maximum of 0.18 cat.%, and even more preferably to a maximum of 0.17 cat.%. The positive effects of a low antimony proportion can also be seen from the results of Application Example 6.However, for a particularly fine distribution of the germ source in the glass, at least 0.02 cat.%, more preferably at least 0.05 cat.%, more preferably at least 0.08 cat.%, more preferably at least 0.09 cat.%, more preferably at least 0.1 cat.%, and particularly preferably at least 0.15 cat.% is used. In an alternative embodiment, the glass is free of antimony.

[0057] By advantageously selecting the antimony content according to the present invention, a glass can preferably be obtained whose transmission value at 260 nm and a sample thickness of 1 mm is preferably at least 1.2%, more preferably at least 1.5%, more preferably at least 1.8%, more preferably at least 2%, more preferably at least 2.5%. Furthermore, with an advantageous selection of the antimony content according to the present invention, the exposure time required for sufficient crystallization at an exposure dose preferred according to the invention is at most 15 minutes, at most 10 minutes, more preferably at most 5 minutes.By advantageously selecting the antimony content according to the present invention, it is preferably possible to obtain a glass in which, upon exposure to UV light, an exposure depth of at least 1 mm, more preferably at least 2 mm, more preferably at least 2.5 mm, more preferably at least 3 mm, more preferably at least 4 mm, even more preferably at least 5 mm can be achieved.

[0058] As mentioned at the beginning, the glass comprises, in addition to silicon, crystal agonists, and crystal antagonists, at least one nucleating agent pair. The nucleating agent pair, in turn, comprises at least one nucleating agent source, preferably selected from silver, gold, and copper, and a reducing agent, which according to the invention is cerium. Silver is the preferred nucleating agent. The roles played by these two components in the nucleating agent pair can be derived from the reaction equation presented above as an example for the nucleating agent pair cerium and silver. In summary, the reducing agent reduces the cations of the nucleating agent source to the metal, thereby forming nuclei in the glass, which in turn are intended to enable crystal formation.

[0059] According to the invention, it is preferred that the amount of nucleation source in the glass is comparatively high. This is because many small, finely distributed nuclei lead to a finer crystal structure than a smaller number of nuclei in the same glass volume. For this reason, the amount of nucleation source, which is preferably silver ions, should have a proportion of at least 0.001 cat.% in the glass. More preferably, this proportion is at least 0.01 cat.%, more preferably at least 0.03 cat.%, particularly preferably at least 0.05 cat.%. However, if the amount of nucleation source is chosen to be too high, nucleation or precipitation of elemental metal may occur during the melting process. This must be avoided at all costs because, firstly, precipitated metal droplets are not available for nucleation in the glass and, secondly, the glass does not have the required optical quality.Furthermore, the elemental metal droplets impair the transmission properties of the glass, for example, through light scattering. Therefore, the amount of nucleation source in the glass is preferably limited to at most 0.5 cat.% or at most 0.2 cat.%, more preferably at most 0.1 cat.%, and most preferably at most 0.08 cat.%. In preferred embodiments, the glass is free of gold and copper.

[0060] As stated, it is desirable to achieve a large number of nuclei in a given volume after exposure to light. Due to the reaction equation presented above, it is not sufficient to select the highest possible proportion of nuclei source. Rather, it is also necessary to carry out sensitization and adapt the proportion of cerium to the amount of nuclei source used. It is therefore preferred according to the invention that the molar ratio of nuclei source to cerium in the glass according to the invention is at most 10, more preferably at most 7, more preferably at most 6.5, and particularly preferably at most 5.8. A higher amount of nuclei source would at best increase the difficulties during production without significantly improving the fine crystallinity. However, the ratio should naturally not be too low either, so that the amount of nuclei formed is sufficient to achieve particularly fine structures in the photostructurable glass body.

[0061] Due to the simplified processing of the glasses compared to the state of the art, the amount of cerium in the glass can be selected to be comparatively high. Finally, due to the relatively oxidizing melting process, a certain proportion of the cerium will be in the 4+ oxidation state. This suppresses unwanted nucleation during production to a certain extent. At the same time, the amount of nucleation source, as well as the amount of cerium, can be selected to be relatively high to achieve a fine crystal structure, which in turn enables particularly fine structuring.

[0062] The amount of cerium (as the sum of Ce 3+ and Ce 4+) in the glass is accordingly preferably at least 0.001 cat.%, further preferably at least 0.005 cat.%, more preferably at least 0.008 cat.% and particularly preferably at least 0.01 cat.%. The glass bodies according to the invention should be photostructurable. This means that after exposure to UV light of a specific wavelength and a subsequent tempering step, they can be selectively crystallized and then structured (etched). However, the proportion of cerium in the glass must not be increased arbitrarily, since this would increase the photosensitivity, but on the other hand would also suppress the permeability for UV light of the relevant wavelength. Finally, for exposing the glass bodies (just as in the prior art), UV light of a wavelength is used at which Ce 3+ absorbed. Is the content of Ce 3+in the glass is therefore very high, so exposure to arbitrarily deep is not possible. This reduces the maximum achievable structural depth. For this reason, the cerium content in the glass is preferably limited to a maximum of 0.3 cat.% or a maximum of 0.2 cat.%, further preferably a maximum of 0.1 cat.%, more preferably a maximum of 0.05 cat.% and particularly preferably a maximum of 0.025 cat.%. In order for the desired effect according to equation I to occur, cerium should be present in the glass in an amount of at least 0.001 cat.%, in particular at least 0.005 cat.% and particularly preferably even at least 0.008 cat.% or 0.01 cat.%. In the prior art, attempts have been made to reduce the susceptibility of glasses to crystallization by reducing the amount of nucleating agent. This certainly works, but it also limits the photosensitivity of the glasses to such an extent that structuring is made very difficult.

[0063] Preferably, the molar content of nucleus source in the glass is at least twice as high as the cerium content; more preferably, the molar ratio of nucleus source to cerium is at least 2.2, more preferably at least 2.5, particularly preferably at least 3, and especially at least 4.5. A balanced ratio of nucleus source, in particular silver, to cerium results in advantages during crystallization. In the presence of a relatively larger amount of nucleus source, more nuclei form, which in turn lead to smaller crystals. According to the invention, the cerium content is rather low relative to the nucleus source, since, due to sensitization, a particularly large amount of this component is not required for nucleation. However, the stated ratio of silver to cerium should not exceed a certain value, since otherwise the relative amount of cerium is insufficient to induce sufficient nucleation.

[0064] In special embodiments, it may be useful to further limit the ratio of nucleation source to cerium. This is particularly the case when only a small structural depth can be achieved by UV exposure. An increase in the achievable structural depth can indeed be achieved by reducing the cerium content, as described above. However, it has surprisingly been found that even without reducing the cerium content, a greater structural depth can be achieved if a lower ratio of nucleation source to cerium is selected. This can be useful compared to reducing the cerium content because it allows a relatively high structural depth even with a relatively oxidizing melt process and consequently a relatively high Ce 4+ / Ce 3+ -ratio due to the relatively high total content of cerium still enough Ce 3+ as a reducing agent for Ag +is available. In such an embodiment, the ratio of nucleation source to cerium in the glass according to the invention is preferably at most 5.5, more preferably at most 5.2, particularly preferably at most 4.9.

[0065] The glass components described herein are not exhaustive. The glass may therefore contain additional components not mentioned here. In preferred embodiments, however, the glass consists of at least 90 cat.% of the components mentioned herein with regard to the cations. In further preferred embodiments, the glass consists of at least 95 cat.%, further preferably at least 97 cat.%, and even more preferably at least 99 cat.% of the components mentioned herein. In a particularly preferred embodiment, the glass consists of 100 cat.% of the components discussed herein.

[0066] Preferably, the glass is free of molecular hydrogen (H2). Molecular hydrogen can lead to the formation of atomic silver and thus to nucleation independent of irradiation.

[0067] When this description states that the glass does not contain a certain component or is free of a certain component, this means that the component is not intentionally added to the glass. This does not exclude the possibility that this component may be present in the glass as an impurity. Impurities should typically and preferably not exceed 0.1 percent by weight of the glass, more preferably no more than 100 ppm, more preferably no more than 10 ppm, and even more preferably no more than 1 ppm. In a preferred embodiment, the components so designated are present in the glass according to the invention at most in an amount that is below the detection limit.

[0068] A preferred glass comprises the following components in cat.%: And 4+ 45 to 65 Crystal agonists 30 to 45 Crystal antagonists 3.5 to 9

[0069] In a preferred embodiment, the glass comprises the following components in cat.-%: And 4+ 45 to 65 Crystal agonists That + 25 to 40 K + 0 to 8 That + 0 to 8 Crystal antagonists B 3+ 0 to 5 Al 3+ 0 to 10 Zn 2+ 0 to 4 Sb 3+ 0 to 0.4 Nucleating agents What 3+ / What 4+ >0 to 0.3 At + >0 to 0.5

[0070] In addition to the cations, the glass also contains anions, which are preferably selected from the group consisting of O 2- , F - , Br - , Cl - and SO4 2- . The molar fraction of O 2- The anion content should preferably be at least 50% (anion %), more preferably at least 70%, more preferably at least 90%, more preferably at least 98%, and particularly preferably at least 99%. In a preferred embodiment, the glass is entirely oxidic, i.e., it contains only O 2- as anions and is free of other anions.

[0071] The glass preferably contains only small amounts of halides. It is preferred that the halide content of the anions be limited to a maximum of 5 anion%, more preferably a maximum of 3 anion%, and even more preferably a maximum of 1 anion%. According to the invention, halides are preferably understood to mean the anions of Cl, F, and Br. In particular embodiments, the glass is free of the anions of Cl, F, and / or Br or comprises these components in proportions of no more than preferably 3 anion%, 2 anion%, or 1 anion%.

[0072] The glass preferably contains essentially no colloidal silver prior to irradiation with UV light. The silver preferably present in the glass is in particular present in a proportion of at least 95%, more preferably at least 99%, in the form of Ag. + before.

[0073] The glass should preferably not contain more than 5 cat.% of Ti 4+(titanium). Titanium impairs the transmission of the glass, particularly in the UV range, which negatively impacts the achievable structural depth. The titanium content is preferably limited to a maximum of 3 cat.%, more preferably a maximum of 1 cat.%. Preferred embodiments contain titanium in amounts of less than 0.2 cat.% or are titanium-free.

[0074] The glass is preferably free from components not mentioned herein, in particular from the cations of La, Nb, W, Hf, Bi, Y, Yb, Pb, As, Ta, Gd and / or Eu.

[0075] It has proven advantageous to limit the content of alkaline earth metal cations in the glass, in particular to up to 10 cat.%, preferably up to 5 cat.%, more preferably up to 2 cat.%. In particularly preferred embodiments, the glass comprises at most 1 cat.% of alkaline earth metal cations or is even free of them. Among alkaline earth metal cations, Mg are preferred according to the invention. 2+ , Ca2+ , Ba 2+ and Sr 2+ In special embodiments, the glass is free of Mg 2+ , Ca 2+ , Ba 2+ and / or Sr 2+ or comprises these components in proportions of preferably no more than 3 cat.%, 2 cat.%, or 1 cat.%. In particularly preferred embodiments, the glass is free of barium.

[0076] The glasses of the present invention are either cooled relatively slowly during the cooling of the melt or, after rapid cooling of the melt, are heated again to a certain temperature T1 in a post-treatment step and then slowly cooled to a temperature T2. For the purposes of this invention, we refer to these alternative process steps as "sensitization."

[0077] The method according to the invention preferably comprises a sensitization step. Sensitization is characterized in that the glass for the glass body is cooled from an initial temperature T1 to a target temperature T2. The initial temperature T1 lies in a range that allows the diffusion of ions in the glass to a certain extent; this is a temperature range that is at least above the glass transition temperature T G of the glass, in particular at least 25°C above T G This adjusts the cooling state of the glass. Only when the target temperature T2 is reached, which according to the invention is at least 150°C below T1, is the viscosity in the glass preferably high enough again that no further diffusion and no further change in the cooling state of the glass occurs.

[0078] In preferred embodiments, the starting temperature T1 is at least 400°C, more preferably at least 425°C, more preferably at least 450°C, and most preferably at least 475°C. A certain minimum temperature is required to allow the cooling state to be established. Therefore, T1 must be above T G of the glass. In preferred embodiments, T1 is at least 25°C, more preferably at least 40°C above T G However, at excessively high temperatures, the tendency to crystallize increases, so that an excessively high temperature T1 can lead to crystallization. Therefore, T1 preferably does not exceed a value of 1000°C, more preferably 800°C, more preferably 600°C, and particularly preferably 550°C. In particularly preferred embodiments, T1 = 500°C. T1 is preferably below the softening temperature of the glass, in particular at least 100°C below the softening temperature.

[0079] The temperature T2 is at least 150°C below T1. T2 is preferably below T G of the glass. In preferred embodiments, T2 is at least 20°C, further preferably at least 100°C, more preferably at least 200°C, and particularly preferably at least 220°C. So that the ion mobility at T2 drops back to a negligibly small value, it is preferred that T2 be at most 400°C, further preferably at most 350°C, and more preferably at most 300°C. In a particularly preferred embodiment, T2 = 240°C.

[0080] The preferred sensitization leads to the cooling state preferred according to the invention. Sensitization involves cooling the glass, either from the melt or as a post-treatment on a glass body, from T1 to T2. Accordingly, the glass is cooled, for example, from the melt, possibly in a mold, to T1, or a glass body is heated to T1. The glass is then cooled, if necessary, from T2 to room temperature.

[0081] In one embodiment, the glass for the vitreous body is cooled continuously from temperature T1 to T2 during sensitization. "Continuously" means that cooling occurs continuously from T1 to T2 without the glass being held at specific temperature levels. In particular, this refers to cooling at a substantially constant cooling rate. If further cooling to room temperature is carried out after cooling to T2, this further cooling can also occur continuously. Room temperature is preferably 20°C.

[0082] In another embodiment, the glass undergoes various cooling stages during sensitization. The glass is preferably cooled from temperature T1 to a temperature T1.1, then to a temperature T1.2, and so on. It is preferred that the glass is cooled to temperature T2 via at least two intermediate stages, in particular at least three and particularly preferably at least four intermediate stages. Cooling is preferably carried out via a maximum of seven, further preferably at most six, and particularly preferably at most five intermediate stages. In such an embodiment, the glass can be cooled continuously via at least one annealing furnace. This enables continuous processing. Sensitization preferably takes place by passing the glass through zones of different temperatures to ensure cooling.This type of cooling optionally, but not necessarily, means that the temperature of the glass is maintained at the respective stage. Rather, the glass can slowly adjust to the temperature of that stage within a temperature stage and then be moved to the next stage, as can be achieved in a cooling sequence using temperature zones on a cooling belt.

[0083] When passing through various cooling stages, the glass is preferably held at a temperature level for 10 to 40 minutes each. The temperature levels are preferably spaced apart by at least 5°C, in particular at least 10°C, and in particular at most 50°C. The glass does not necessarily have to reach the temperature of the respective stage before being transferred to the next temperature stage.

[0084] Sensitization of the glass thus occurs as a treatment step in the process according to the invention, and the initial temperature T1 is then reached by cooling the glass in the mold. It is also disclosed that sensitization takes place as a separate post-treatment step, in which the pressed glass body is reheated to the initial temperature T1 and then cooled to T2 in a controlled manner.

[0085] Before sensitization, the crystallization tendency of the glass according to the invention is not as pronounced as after sensitization.

[0086] Whenever sensitization is mentioned here, it always refers to a processing step that takes place before the glass is exposed to light. The heat treatment step after the glass is exposed is referred to as "annealing" in accordance with the technical literature.

[0087] Sensitization adjusts the cooling state of the glass. This also brings the density of the glass closer to that of the underlying crystal system. The glass becomes denser. This affects both the mass density and the refractive index. These glasses preferably have a refractive index η d at 546.1 nm and 25 °C of at least 1,500 and in particular at most 1,600. Furthermore, the glasses preferably have a mass density ρ of at least 2.35 g / cm 3 , more preferably at least 2.36 g / cm 3 In preferred embodiments, the density is less than 2.4 g / cm 3 and preferably less than 2.39 g / cm 3High density leads to the formation of smaller crystallites after exposure and annealing due to suppressed diffusion of the crystal components. However, the closer the density is to the density of the crystal, the higher the risk of unwanted, non-selective crystallization. Unless otherwise stated or readily apparent to the skilled person, measurements herein are carried out at a temperature of 25°C and an atmospheric pressure of 101.325 kPa.

[0088] The glass preferably has a softening point of at least 600°C, in particular at least 650°C. Preferably, the softening point is at most 750°C, and in particular at most 700°C.

[0089] As mentioned previously, the glass is melted in a relatively oxidizing manner. As a result, the cerium component is also present in its tetravalent oxidation state. However, the tetravalent oxidation state does not participate in the nucleation reaction described above (Equation I). It can be seen that sensitization increases the proportion of cerium in the trivalent oxidation state in the glass. 3+ absorbed at approximately 314 nm, i.e., in the UV. To ensure that the glass forms sufficient nuclei upon exposure, it is preferred according to the invention that the glass has a transmission of no more than 50% at a wavelength of 314 nm and a thickness of 1 mm. If the transmission at this wavelength is more than 50%, this may mean that the concentration of Ce 3+ in the glass is not sufficient to trigger sufficient nucleation upon exposure.

[0090] Particularly preferably, the transmission at 314 nm and a thickness of 1 mm is not more than 40%, more preferably not more than 39%. Nevertheless, the absorption at this wavelength should not be too high so that the UV radiation can penetrate far enough into the glass to achieve deep structures. In this respect, the transmission at 314 nm and a thickness of 1 mm should preferably be at least 10%, more preferably at least 20%, more preferably at least 25% or at least 30%, and particularly preferably at least 35%. The transmission is in particular the pure transmission, i.e. the transmission of the glass without reflection influences. The transmission of an example glass as a function of the wavelength is shown in Fig. shown.

[0091] To achieve this, it is preferred according to the invention that the amount of cerium in the glass is limited. The cerium content should be selected depending on the thickness of the glass body. In preferred embodiments, the cerium content in the glass is limited to a maximum amount of 4×10 -3 % per millimeter of glass thickness. A value of not more than 3×10 -3 Cat.% per millimeter of glass thickness. However, in order for the amount of cerium to be sufficient to trigger the necessary nucleation, a minimum amount of cerium of at least 2×10 -3Cat. % per millimeter of glass thickness. The glass body according to the invention preferably has a thickness of at least 1 mm, more preferably at least 3 mm, and particularly preferably at least 5 mm. However, the thickness preferably does not exceed a value of 20 mm, more preferably 15 mm. The glass body is preferably a pressed glass, in particular not a laminate or layered composite. The glass body preferably consists of the glass described herein and in particular not of ceramic or glass-ceramic.

[0092] The glass bodies according to the invention have a diameter of at least 4 inches, more preferably at least 5 inches, more preferably at least 6 inches and in particular at least 7 inches at their widest point. The process according to the invention enables such particularly large geometries compared to the prior art. In conventional processes, the size of the compression molds was limited to smaller dimensions, since otherwise cooling could not be carried out quickly enough to avoid crystallization. Nevertheless, according to the invention, the maximum size is preferably limited to up to 15 inches, preferably up to 12 inches, particularly preferably up to 10 inches. In one embodiment, the compression mold can be heated to prevent the melt from quenching too quickly.

[0093] One advantage of these glasses is that they can be produced in a continuous manufacturing process. The melting of the glass batch preferably takes place in a tank. From there, the glass melt preferably flows into a refining vessel, where a refining step takes place. From the refining vessel, the glass melt preferably flows into a crucible, particularly a platinum crucible, which may have a stirrer. The glass melt is homogenized in the crucible. Stirring can achieve a particularly high level of homogeneity. From the crucible, the melt can be transferred into the mold.

[0094] The continuous manufacturing process allows for glasses with particularly high homogeneity, as the occurrence of streaks in particular can be drastically reduced. This results in particularly small fluctuations in transmission, density, and refractive index.Preferably, the glass is so homogeneous that at a wavelength of 260 nm and / or 280 nm, the standard deviation of the transmission is at most 15%, more preferably at most 10%, more preferably at most 7%, more preferably at most 5%, more preferably at most 4%, more preferably at most 3%, even more preferably at most 2%, most preferably at most 1%, even more preferably at most 0.8%, even more preferably at most 0.5%, even more preferably at most 0.4%, even more preferably at most 0.2% of the corresponding transmission mean value, wherein the mean value and standard deviation are determined from at most 100, preferably at most 60, more preferably at most 40, more preferably at most 30 independent measured values. The mean value and standard deviation are preferably determined from at least 5 independent measured values, more preferably from at least 10 independent measured values, more preferably from at least 15 independent measured values.In preferred embodiments, the mean and standard deviation are determined from 50 independent measured values, more preferably from 40 independent measured values. The independent measured values ​​are obtained by measuring the transmittance at different points on the glass. Preferably, the distance between any two adjacent measuring points is at least 0.1 mm, more preferably at least 0.5 mm, more preferably at least 1 mm, more preferably at least 5 mm, more preferably at least 10 mm. Those skilled in the art will know how to determine the standard deviation based on a group of measured values. The standard deviation corresponds to the square root of the sum of the squared deviations of the individual measured values ​​from the mean of the measured values, wherein this sum is divided by the number of measured values ​​minus one before taking the square root.

[0095] The transmission value at 260 nm and a sample thickness of 1 mm is preferably at least 0.2%, more preferably at least 0.5%, more preferably at least 1%, more preferably at least 1.2%, more preferably at least 1.5%, more preferably at least 1.8%, more preferably at least 2%, more preferably at least 2.5%. The transmission value at 260 nm and a sample thickness of 1 mm is preferably at most 5%, more preferably at most 4%, more preferably at most 3.5%, more preferably at most 3%. The transmission value at 280 nm and a sample thickness of 1 mm is preferably at least 8%, more preferably at least 9%, more preferably at least 10%, more preferably at least 11%, more preferably at least 12%, more preferably at least 13%, more preferably at least 15%, more preferably at least 16%.Preferably, the transmission value at 280 nm and a sample thickness of 1 mm is at most 30%, more preferably at most 25%, more preferably at most 20%.

[0096] It is remarkable that such low transmission fluctuations can be achieved even at wavelengths of 260 nm and 280 nm, since these wavelengths are precisely at the UV edge and therefore higher standard deviations would generally be expected. Furthermore, these wavelengths overlap at least slightly with the absorption range of Ce. 3+ , so that the small transmission fluctuations are a good indicator of the homogeneous distribution within the glass.

[0097] Because only minor deviations in the transmission values ​​occur, transmission measurements are ideal for quality control of glass. Furthermore, the small fluctuations in refractive index, due to the possibility of improved optical focusing, preferably enable exposure of the glass body not only on its surface or in near-surface areas, but also deep within the glass body using an appropriately focused laser. The high homogeneity of the glasses also preferably results in more homogeneous etching rates during the etching process, which, due to a reduction in etching errors, can result in more precisely obtainable structures. Furthermore, a more homogeneous etching rate preferably reduces the occurrence of etching-related streaks. The very low-streak production facilitates the applicability of the aforementioned processes.

[0098] Manufacturing in a continuous process not only increases the homogeneity within a piece of glass described above, but also the homogeneity between different batches.

[0099] The glass body produced according to the invention can be cut into glass wafers using a cutting method, in particular by sawing, which can then be ground and / or polished. A particularly preferred cutting method is wire sawing, in particular multi-wire sawing, for example multi-wire slicing (MWS). The preferred cutting material is a steel wire. In preferred embodiments, emery is the internal medium between the raw glass and the steel wire. In such embodiments, the particle size of the internal medium is preferably in a range between 100 and 300 mesh according to the US standard, more preferably in a range between 150 and 250 mesh according to the US standard, more preferably approximately 200 mesh according to the US standard. The cutting speed is preferably in a range between 2 and 20 mm per hour, more preferably between 4 and 15 mm per hour, and even more preferably between 6 and 10 mm per hour.If the cutting speed is too slow, the cutting will not be very efficient. If the cutting speed is too high, the glass may break or the cutting wire may tear.

[0100] Preferably, the cut glass wafers, optionally after grinding and polishing, have global thickness variations (English: “total thickness variation” (TTV)) of at most 30 µm, more preferably at most 20 µm, more preferably at most 15 µm, more preferably at most 10 µm, more preferably at most 8 µm, more preferably at most 5 µm for an area of ​​325 cm 2 Of course, the specified TTV is only achieved with smaller areas, for example with an area of ​​180 cm 2 .

[0101] The raw materials used are important for adjusting the redox state of the glass melt. The following list shows the preferred raw materials for establishing suitable melting conditions. However, other measures for adjusting the redox state are also known to those skilled in the art.

[0102] In addition to the raw materials, further measures can also be taken to adjust the redox distribution of the melt. For example, in one embodiment of the invention, oxidizing gases can be introduced into the melt (bubbling). Furthermore, the temperature of the melt is important for the redox state. In particular, high melting temperatures lead to reducing melting conditions. Glass component preferred raw material And 4+ sand Crystal agonists That + Lithium carbonate K + Potash That + Soda, sodium sulfate, sodium antimonate Crystal antagonists B 3+ Boron trioxide Al 3+ aluminum hydroxide Zn 2+ zinc oxide Sb 3+ Sodium hexahydroxidoantimonate Nucleating agents What 3+ / What 4+ Cerium oxide At + Silver oxide, silver nitrate

[0103] Depending on the desired composition of the anions in the glass, the corresponding halides can also be used. However, according to the invention, it is preferred that the glasses contain as few halides as possible.

[0104] This invention also encompasses a method for photostructuring a glass body according to the invention. The photostructuring method comprises, in particular, the steps of exposing and structuring the glass body, which comprises and in particular consists of the glass described herein. The exposure is preferably carried out at a wavelength that substantially corresponds to the absorption maximum of Ce 3+ in the glass. This wavelength lies in the UV, specifically in the range between 300 nm and 320 nm, especially at 310 nm. During exposure, areas not to be exposed are preferably covered with a mask.

[0105] The UV exposure dose must be high enough to ensure adequate photostructuring. UV exposure is preferably carried out at a dose of more than 0.1 J / cm 2 More preferably, the dose is at least 1 J / cm 2 , more preferably at least 3 J / cm 2 , more preferably at least 5 J / cm 2 , more preferably at least 7 J / cm 2 , even more preferably at least 10 J / cm 2 However, the dose should not be too high. Preferably, the dose should not exceed 100 J / cm 2 , more preferably not more than 50 J / cm 2 , even more preferably not more than 25 J / cm 2 .

[0106] Preferably, the exposure time required for sufficient crystallization at a preferred dose according to the invention is at most 20 minutes, more preferably at most 15 minutes, more preferably at most 10 minutes, more preferably at most 5 minutes.

[0107] In a preferred embodiment, the exposure takes place with a laser. The laser is preferably a pulsed laser. The laser is preferably a nanosecond laser, more preferably a picosecond laser, and even more preferably a femtosecond laser. Multiphoton absorption enables working with long wavelengths in the visible range or, more preferably, even in the IR range, where the glass has a particularly high transmission, allowing exposure to great depths. The excitation of components absorbing in the UV range, such as Ce 3+ In such embodiments, the etching preferably takes place predominantly in the areas on which the laser is focused. The laser is particularly preferably a titanium:sapphire femtosecond laser. Laser exposure also preferably enables the creation of particularly fine structures and / or structures located particularly deep within the glass body in the subsequent etching step.

[0108] The high homogeneity of the glasses produced by the process of the present invention, in particular with regard to transmission and refractive index, preferably enables exposure even at great depths within the glass body. Exposure is preferably carried out using a focused short-pulse laser or a UV source, for example a UV lamp or a UV burner. The exposure depth is preferably at least 0.5 mm, more preferably at least 1 mm, more preferably at least 2 mm, more preferably at least 5 mm, more preferably at least 10 mm, more preferably at least 15 mm, more preferably at least 20 mm. The exposure depth is preferably even up to 50 mm, more preferably up to 100 mm, more preferably up to 200 mm, more preferably up to 300 mm, more preferably up to 500 mm, more preferably up to 1000 mm, and even more preferably up to 2500 mm.However, it must be noted that with increasing exposure depth, the area in focus of the short-pulse laser becomes longer or blurrier. Therefore, exposure with a focused short-pulse laser should not be carried out at too great a depth. The exposure depth is preferably determined optically via the depth of exposure-dependent crystallization. The measurement is performed from a side view. The glass body is exposed to UV light over its entire surface. The glass body is then annealed to crystallize the exposed parts. The sample is then cut in half, and the severed part is inspected from the side. Immersion oil is preferably used to avoid the need to polish the severed surface. The exposure depth is then measured with a microscope. The crystallization limit can be clearly seen using this method.

[0109] Particularly preferably, undercut structures can be produced. For this purpose, various UV lasers are preferably used which differ in terms of their penetration depth into the glass body. This allows exposure to different depths with different doses. Since the actual structuring takes place in a subsequent etching step, two, more preferably even a single exposure pass are preferably sufficient, so that high exposure speeds of preferably at least 1 m / s, more preferably at least 5 m / s, even more preferably at least 10 m / s can be achieved. A wafer can preferably be processed in less than 12 hours, more preferably less than 6 hours, more preferably less than 3 hours, more preferably less than 2 hours, more preferably less than 1 hour. Predetermined breaking points can also preferably be created by stepwise ceramization of an already structured element.

[0110] The structuring of the exposed glass body is preferably carried out by etching, in particular with an HF-containing etching solution. The HF concentration in the etching solution is preferably between 5 and 20 wt.% in water. The HF concentration in the etching solution is particularly preferably 10 wt.%. Structuring results in structured glass bodies that have a better, or at least equivalent, structure in terms of structure depth and aspect ratio compared to the prior art.

[0111] The structural depth in the structured glass bodies obtainable with the glass according to the invention is preferably up to 0.1 mm, more preferably up to 0.2 mm, more preferably up to 0.5 mm, more preferably up to 1 mm, more preferably up to 2 mm, more preferably up to 3 mm, even more preferably up to 4 mm, and most preferably up to 5 mm. According to the invention, "structural depth" is understood to mean the height difference in the etching direction between a crystallized region and a non-crystallizing region.

[0112] According to the invention, "aspect ratio" is understood to mean the ratio of the depth of a structure to its width. It is naturally advantageous if large aspect ratios are possible. With the glass according to the invention, aspect ratios of up to 80:1, preferably up to 60:1, more preferably up to 50:1, and particularly preferably up to 40:1 can be achieved. The achievable aspect ratio is preferably at least 10:1, further preferably at least 15:1, and even more preferably at least 20:1.

[0113] To achieve particularly high structural depths, the glass's transmission at the exposure wavelength should be as high as possible. Therefore, if a high structural depth is desired, the transmission parameters specified above should be observed. Among other things, the amount of Ce is important for the transmission at the exposure wavelength. 3+ decisive.

[0114] After exposure and before structuring, the glass bodies to be structured are preferably annealed. The annealing serves to induce crystal formation around the nuclei formed during exposure. For this purpose, the glass body to be structured is heated to a temperature that enables the formation of crystals and is in particular above the glass transition temperature of the glass. This temperature is preferably at least 400°C, more preferably at least 455°C, more preferably at least 500°C, more preferably at least 550°C. Furthermore, this temperature should preferably not exceed a value of 650°C, more preferably 600°C, and particularly preferably 580°C. Most preferably, this temperature is in a range from 555°C to 565°C, and even more preferably the temperature is approximately 560°C.Although the etching ratio can be higher at high temperatures, the stated preferred temperatures are nevertheless preferred because crystallization can occur to a greater extent even in non-exposed areas if the annealing temperature is very high. Furthermore, a certain holding time should be maintained in this temperature range so that sufficient crystals of the desired size can form. The holding time is preferably at least 10 minutes. In general, if the temperature is too low or the holding time is too short, not enough crystals will form, and if the temperature is too high or the holding time is too long, crystal growth will be too pronounced, resulting in particularly large crystals. Large crystals are disadvantageous because they result in the structured surface having a comparatively high roughness. Small crystals are therefore preferred.After the etching process, the surface particularly preferably has a roughness Ra of less than 1000 nm, more preferably less than 100 nm, more preferably less than 50 nm, more preferably less than 20 nm, more preferably less than 10 nm, more preferably less than 5 nm, more preferably less than 3 nm, more preferably less than 1 nm. The roughness is preferably measured using a tactile profilometer. The roughness is particularly preferably measured using a Dektak XT™ Stylus Profiler from BRUKER.

[0115] The etching rate describes the removal of material from the surface of the glass body by the etching solution. The unit of the etching rate is µm / min. The structuring of the surface is achieved by the etching rate being higher in the areas previously exposed to UV radiation than in the unexposed areas. The etching rate in the unexposed areas is preferably at most 5 µm / min, more preferably at most 2 µm / min, more preferably at most 1 µm / min, and even more preferably at most 0.5 µm / min. In the exposed areas, the etching rate is preferably at least 10 µm / min, more preferably at least 20 µm / min, more preferably at least 30 µm / min, more preferably at least 40 µm / min, and even more preferably at least 50 µm / min.

[0116] The etch ratio is the ratio of the etch rate in the exposed areas to the etch rate in the unexposed areas. The etch ratio is preferably at least 10 to 1, more preferably at least 20 to 1, more preferably at least 30 to 1, more preferably at least 40 to 1, and even more preferably at least 50 to 1.

[0117] Due to the preferred sensitization of the glass according to the present invention, particularly pronounced crystal phases are formed. Although the exposed areas are not pure ceramic, but rather a mixture of glass and crystals (glass ceramic), the proportion of crystals in this glass-ceramic phase is particularly high according to the invention. In the crystallized glass body of the present invention, the crystal content in the glass-ceramic phase is preferably at least 10 vol.%, more preferably at least 20 vol.%, more preferably at least 40 vol.%, and particularly preferably at least 60 vol.%. However, the crystal content in the glass-ceramic phase is less than 100 vol.%.

[0118] In one embodiment of the method according to the invention for structuring glass bodies, glass bodies are used that were previously formed in the hot-forming process according to the invention. Such processes are known to those skilled in the art. However, they could not be carried out with photostructurable glasses from the prior art, since all these processes must be carried out at temperatures that favor crystallization of the glass. The glasses used here, however, can be subjected to a hot-forming process in an "insensitive" state and only subsequently sensitized. During hot-forming, the crystallization tendency of the glasses according to the invention is not so pronounced that crystallization occurs. Only through sensitization, which is described above, is the crystallization tendency increased to such an extent that photostructuring becomes possible.

[0119] Consequently, the method according to the invention comprises • first melting the glass, • followed by hot forming, • Sensitization of the glass during or after hot forming • and then structuring as described above.

[0120] The glass then produces a structured glass body that has excellent properties in terms of durability, structural depth, aspect ratio and internal quality.

[0121] Particularly preferred structures are through holes. Through holes are holes that extend through the entire thickness of a glass body. Through holes preferably have a substantially cylindrical shape, with the height of the cylinder corresponding to the thickness of the glass body. The diameter of a through hole is the greatest distance between opposite edges of the hole when measured at right angles to the height axis of the hole. The shape of the through holes may deviate from the cylindrical shape. For example, the through holes may have a substantially cuboid shape. In any case, however, the diameter of a through hole is defined as the greatest distance between opposite edges of the hole when measured at right angles to the height axis of the hole. The diameter of a through hole is preferably determined microscopically.In a preferred embodiment, through-holes with a diameter of at most 500 µm, more preferably at most 250 µm, more preferably at most 100 µm, more preferably at most 50 µm, more preferably at most 35 µm, more preferably at most 30 µm, even more preferably at most 20 µm, even more preferably at most 10 µm can be obtained. Preferably, holes can be obtained that are so close to one another that the distance between their centers is at most 1.5 times the hole diameter. More preferably, the distance is even only at most 1.3 times, more preferably at most 1.2 times, even more preferably at most 1.1 times the hole diameter.Preferably, holes can be produced with such accuracy that, with a planned hole diameter of 30 µm and a glass thickness of 500 µm, the deviations from the planned hole diameter are at most 30 µm, more preferably at most 15 µm, more preferably at most 10 µm, more preferably at most 5 µm, more preferably at most 2 µm, more preferably at most 1 µm, even more preferably at most 0.5 µm. Due to such accuracy, the deviations of the diameters of individual through-holes in a glass body according to the invention, with a planned hole diameter of 30 µm and a glass thickness of 500 µm, are preferably at most 30 µm, more preferably at most 15 µm, more preferably at most 10 µm, more preferably at most 5 µm, more preferably at most 2 µm, more preferably at most 1 µm, even more preferably at most 0.5 µm.Preferably, through-holes can be obtained with such small deviations from the planned hole diameter that the standard deviation from the planned hole diameter is at most 5 µm, more preferably at most 3 µm, more preferably at most 2 µm, more preferably at most 1 µm, more preferably at most 0.5 µm, more preferably at most 0.2 µm, even more preferably at most 0.1 µm. Furthermore, with a planned hole diameter of 30 µm and a glass thickness of 500 µm, through-holes can preferably be obtained whose pitch angle is less than 5°, more preferably less than 2°, even more preferably less than 1°, particularly preferably less than 0.5°. The pitch angle describes the deviation of the longitudinal direction of the through-holes from the normal to the surface of the glass body.

[0122] A glass body produced according to the invention can be cut into glass wafers using a cutting process, in particular by sawing, which can then be ground and polished. Such glass wafers preferably have a thickness of at most 10 mm, more preferably at most 5 mm, more preferably at most 2 mm, more preferably at most 1 mm, and particularly preferably at most 500 µm, more preferably at most 300 µm.

[0123] The glasses according to the invention can be used in the field of microfluidics. For example, samples can be analyzed within photostructured glass bodies. For this purpose, it is advantageous if the glasses exhibit good permeability to infrared radiation. Infrared radiation can be used to perform various qualitative and quantitative microscopic detection methods. It is preferred according to the invention that the glasses of this invention exhibit a transmission of at least 70% at a wavelength of 900 nm and a thickness of 1 cm.

[0124] The glasses are preferably also transparent in the visible light range from 400 to 800 nm. This preferably means that, in the entire wavelength range from 400 nm to 800 nm, at a thickness of 1 cm, the pure transmission of the glass is always at least 85%, more preferably at least 90%, and particularly preferably at least 95%.

[0125] The glass bodies of the present invention can be used in a structured and / or unstructured form in various applications. According to the invention, the use in components or as components 1. in microtechnology, 2. in microreaction technology, 3. in electronic packaging, 4. for microfluidic components, 5. in or as FED spacer, 6. for biotechnology (e.g. titer plates), 7. as an interposer, 8. in or as three-dimensionally structurable antennas.

[0126] Preferably, the glass bodies of the present invention can be used as substrates or glass circuit boards (GCB) in the areas a. Microfluidics / Biotechnology, for example i. Lab-on-chip / Organ-on-chip, ii. Micro mixer, iii. Microreactor, iv. printer head, v. titer plates, vi. Chip electrophoresis, b. Semiconductors, for example i. Logic circuit / integrated circuit, ii. Storage, iii. Contact image sensor, iv. Spacer for field emission display (FED), v. Integrated Passive Device (IPD), vi. capacitors, vii. Inductors, viii. Resistances, c. Sensors, for example i. Flow / temperature sensors, ii. gyroscopes / accelerometers, d. Radio frequency micro-electromechanical systems (RF / MEMS), for example i. Antennas, ii. capacitor, iii. Filter / Duplexer, iv. Switch, v. oscillator, e. Telecommunications, for example i. Optical alignment chips ii. Optical waveguides iii. Optical interconnections.

[0127] The invention also relates to the use of the glass body according to the invention in a method for producing a structured glass body. Examples

[0128] The following table shows the compositions of the glasses used according to the invention in cat.%. The glasses shown are all oxidic, meaning that the proportion of non-oxygen anions is at most 2 anion%. Table 1 - Example glasses in cat.% component B1 B2 B3 B4 B5 And 4+ 59,6 52,1 60,4 53 60,1 K + 3,8 5,6 3,4 3,78 4,08 That + 2,5 2,8 0,15 3,79 2,51 At + 0,06 0,06 0,004 0,044 0,043 B 3+ 0,26 0,94 0 0 0 Al 3+ 3,8 5,14 4,27 6,05 3,86 That + 29,2 32,2 31,4 33,3 28,8 Σ(What 4+ ,What 3+ ) 0,011 0,01 0,003 0,007 0,005 Zn 2+ 0,56 1,07 0,27 0 0,54 Sb 3+ 0,17 0,12 0,07 0,118 0,13 Sum of the components 99,96 100,04 99,97 100,09 100,07 Li + / Yes 4+ 0,49 0,62 0,52 0,63 0,48 Σ(Li + , Na + , K + ) 35,5 40,6 34,95 40,9 35,4 Σ(Li + , On + , K + ) / Yes 4+ 0,6 0,78 0,58 0,77 0,59 Σ(B 3+ , Al 3+ , Zn 2+ ) 4,6 7,2 4,5 6,1 4,4 Ag + / Σ(What 4+ ,What 3+ ) 5,45 6 1,33 6,3 8,6 Application example 1

[0129] By pressing glass B1 in a mold, a glass body with a thickness of 15 mm was produced. The melt was cooled in the mold such that the temperature range from 990°C to 600°C was passed through within 11 minutes. Subsequent sensitization adjusted the glass to a cooling state corresponding to a cooling from 500°C to 240°C at an average cooling rate of 80°C / h. The glass was sawn, ground, and polished to a thickness of 0.5 mm. The transmittance was measured at various points on the glass at a wavelength of 280 nm. Forty measurements were taken, and the mean transmittance was 30%. The glass was so homogeneous that the standard deviation of the transmittance was only about 0.4% of the mean transmittance.

[0130] The vitreous body was exposed to UV light at 320 nm with a dose of 10 J / cm 2To create through-holes with a diameter of 40 µm and a hole center distance of 60 µm, the areas not to be exposed were covered with a mask. The glass body was then annealed at 580°C for one hour. The etching step was carried out in a 10% HF solution at room temperature. The etching ratio was 47 to 1. Through-holes with an average diameter of approximately 40 µm were obtained, with a standard deviation of the hole diameter of less than 1 µm. Application example 2

[0131] A glass body was fabricated and exposed as described in Application Example 1. However, the annealing temperature was varied to investigate its influence on the etching rate. The highest etching rate was obtained at an annealing temperature of 580°C. Application example 3

[0132] A glass body was manufactured and processed as described in Application Example 1. However, the planned hole diameter was varied. It was found that the standard deviation is independent of the planned hole diameter. Application example 4

[0133] By pressing glass B2 in a mold, a glass body with a thickness of 45 mm was produced. The melt was cooled in the mold to a temperature range of 990°C to 600°C within 8 minutes. Subsequent sensitization adjusted the glass to a cooling state corresponding to cooling from 550°C to 300°C at a cooling rate of 40°C / h. The glass was so homogeneous that, in 50 measurements at a wavelength of 280 nm, the standard deviation of the transmission was only 0.5% of the corresponding transmission value.

[0134] The vitreous body was exposed to an IR femtosecond laser with a wavelength of 960 nm. The dose was 0.2 J / cm 2 The glass was so homogeneous that focusing at a depth of 20 mm was possible. After 90 minutes of etching at , glass bodies were obtained with two entrance holes, each 500 µm in diameter and 20 mm deep, connected by a channel with a diameter of 100 µm extending from one entrance hole to the other at a depth of 20 mm. Application example 5

[0135] A glass body according to the invention was divided into several parts to obtain several samples. Some of the samples remained untreated and served as control samples, while others were subjected to a sensitization step. An increase in transmittance at 280 nm was observed in the sensitized samples compared to the non-sensitized control samples. It was found that the increase in transmittance correlated positively with the temperature T1 during sensitization. Application example 6

[0136] To determine the influence of antimony on the transmission properties, two glasses according to the invention were compared. They differed only in their antimony content. This was 0.15 cat.% and 0.2 cat.%, respectively. The transmission was 1.2% at a wavelength of 260 nm for a 1 mm thick glass body with the higher antimony content. In contrast, it was surprisingly found that the transmission at 260 nm for a 1 mm thick glass body with the lower antimony content was 1.9%. By increasing the transmission in the UV range, the exposure time required for sufficient crystallization could be reduced from 14 minutes for the glass with the higher antimony content to 5 minutes for the glass with the lower antimony content.Also, with thicker glass bodies, the achievable structural depth increased from 1.7 mm in the glass with the high antimony content to 3 mm in the glass with the lower antimony content. Description of the illustrations Fig. shows the cooling curve of glass B1. Fig. shows a cooling curve with a logarithmic x-axis. Fig.shows the influence of sensitizing a sample glass on the transmission in the UV range. The transmission was measured at 280 nm with a sample thickness of 1 mm. The relative increase in transmission is shown for the sensitized samples A to C compared to a non-sensitized control sample. Samples A to C differ in temperature T1 during sensitization. The temperature T1 was lower for sample A than for sample B and lower for sample B than for sample C. It can be seen that the increase in transmission at 280 nm is greater with increasing temperature T1. Fig. shows the transmission of an example glass with a thickness of 1mm as a function of the wavelength. Fig.shows the dependence of the achieved etching ratio on the annealing temperature. The x-axis represents the annealing temperature, and the y-axis represents the achieved etching ratio. The highest etching ratio is achieved at an annealing temperature of 580°C. Fig. shows the standard deviation of the resulting hole diameter as a function of the planned hole diameter. The standard deviations are shown for both the top (diamonds) and bottom (squares) of the through holes. The standard deviation (in µm) is shown on the y-axis. The planned hole diameter is plotted on the x-axis. The results show that the standard deviation is independent of the planned hole diameter.

Claims

[1] Method for producing a photosensitive glass body comprising the steps a. Providing a mixture of raw materials for the desired glass, b. Melting the mixture, c. Transferring the melt into a mold, d. Pressing the glass in the mold to form the glass body, wherein the melt has a temperature above 1,000°C at the time of transfer into the mold, wherein the melt is cooled in the mold such that the temperature range from 990°C to 600°C is passed through in a period of less than 15 minutes, and wherein the glass Si 4+ , at least one crystal agonist, at least one crystal antagonist and at least one nucleating pair, - wherein the crystal agonists are selected from Na + , K + , and Li + , - wherein the crystal antagonists are selected from Al 3+ , B 3+, Zn 2+ , Sn 2+ and Sb 3+ , - wherein the nucleating pair contains cerium and at least one member from the group silver, gold and copper, and where the molar fraction of crystal agonists in cat.% in relation to the molar fraction of Si 4+ at least 0.3 and at most 0.85, wherein the glass is subjected to a sensitization step following step b. and / or c., which corresponds to cooling from a temperature T1 to a temperature T2 with an average cooling rate K of 10°C / h to 200°C / h, wherein the temperature T1 is at least above the glass transition temperature T G of the glass and the temperature T2 is at least 150°C below T1. [2] The method according to claim 1, wherein the glass comprises the following components in cat.% Si 4+ 45 to 65 crystal agonists 30 to 45 crystal antagonists 3.5 to 9 [3] A method according to any one of the preceding claims, wherein the glass comprises the following components in cat.% And 4+ 45 to 65 Crystal agonists That + 25 to 40 K + 0 to 8 That + 0 to 8 Crystal antagonists B 3+ 0 to 5 Al 3+ 0 to 10 Zn 2+ 0 to 4 Sb 3+ 0 to 0.4 Nucleating agents What 3+ / What 4+ >0 to 0.3 At + >0 to 0.5 [4] Method according to at least one of the preceding claims, wherein the glass contains between 0.02 and 0.2 cat.% Sb 3+ contains. [5] Method according to at least one of the preceding claims, wherein the glass contains anions in addition to the cations, wherein the molar proportion of O 2 - of the anions is at least 99%. [6] Pressed glass body which can be produced by a method according to one of the preceding claims, wherein the glass has a cooling state which corresponds to a cooling from a temperature T1 to a temperature T2 with a cooling rate K of 10°C / h to 200°C / h, wherein the temperature T1 is at least above the glass transition temperature T G of the glass and the temperature T2 is at least 150°C below T1. [7] Pressed glass body according to claim 6, wherein at a wavelength of 260 nm and / or 280 nm the standard deviation of the transmission is at most 15% of the corresponding transmission mean value, wherein the mean value and standard deviation are determined from at most 100 independent measured values. [8] Use of a glass body according to at least one of claims 6 or 7 in a method for structuring glass with the steps - Exposing the vitreous body to UV light, - Tempering of the exposed glass body, - Structuring the vitreous body using an etching solution. [9] Use according to claim 8, wherein an exposure depth of at least 1 mm can be achieved. [10] Structured glass body obtainable according to claim 8 or 9, having a structure depth of at least 1 mm. [11] Crystallized glass body obtainable by exposing and tempering a glass body according to at least one of claims 6 or 7. [12] A glass wafer obtainable by cutting the pressed glass body according to any one of claims 6 or 7, wherein the transmittance value at a thickness of the glass wafer of 1 mm at a wavelength of 280 nm is at least 8%.

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