Method for producing ultra-thin elements made of glass-based material, ultra-thin element made of glass-based material, and use thereof

Abstract

The invention relates to a method for producing ultra-thin elements, to elements made of glass-based material (2, 4) and to the use thereof, in particular made of glass and / or glass ceramic, having a material thickness (d) of 5 to 100 µm by means of at least one ultra-short pulse laser (16) having a laser wavelength in which the element made of glass-based material is at least substantially transparent, wherein the beam profile of the laser beam (20) is shaped such that it has a laser preferred direction LVR. In this way, instances of damage (14) are introduced into the ultra-thin element made of glass-based material (2, 4) along a separating line (12, 121, 122), wherein adjacent instances of damage (14) are spaced at a distance (A) of 15 µm to 50 µm. Particularly good edge strength is thus achieved.

Description

[0001] Method for producing ultrathin elements from glass-based material, ultrathin element made of glass-based material and its use

[0002] The present invention relates to the production of ultrathin elements made of glass-based material, in particular glasses and / or glass ceramics, with a thickness of 5 pm to 100 pm, by directed ultrashort pulse laser processing for the insertion of parting lines. Examples of ultrathin elements made of glass-based material include ultrathin glass sheets, glass films, and / or glass on a roll. The invention also relates to such an ultrathin glass element and its use.

[0003] Description

[0004] Ultrashort pulse laser processing for separating glass-based materials enables higher process efficiencies than purely mechanical separation methods. This improved efficiency applies to both processing speeds and the avoidance or at least reduction of scrap.

[0005] Glass-based materials, as defined in the invention, are all materials that exhibit a glass-like network in at least some areas and / or are derived from a glass-based material. Glass-based materials include, in particular, glasses as such, especially oxide glasses and / or multicomponent glasses, but also glass ceramics obtained by at least partial crystallization of elements from glass-based material. In a broader sense, inorganically or organically coated glass-based materials also fall under this definition. For example, when separating continuous glass ribbons using ultrashort pulse laser processing, edge cutting and / or transverse singulation on the glass ribbon, and optionally in combination with subsequent glass separation, higher glass ribbon speeds or...Drawing and cutting speeds are possible in the cutting process compared to, for example, pure wheel cutting, where the separation and placement processes performed by a worker limit the achievable cutting speeds for rim and cross-scoring. Ultrashort pulse laser processing is also a low-particle process, resulting in fewer contaminations and scratches on the glass. The same applies to the cutting of ultrathin glass sheets, which are processed individually.

[0006] The separation of glass panes by introducing material damage using ultrashort pulse lasers is known per se. Corresponding methods are described, among others, in WO 2018 / 020145 A1 and US 2018 / 0057390 A1.

[0007] The aim is to optimize processing speeds to enable particularly efficient production. US 2018 / 0057390 A1 specifies that the distance A between adjacent defects, also known as pitch, is typically set to 10 pm for glass substrates. For TFT glass substrates with a thickness of 0.5 to 7 mm, a pitch range of 5 to 10 pm is proposed.

[0008] The distance A, or synonymously pitch, between adjacent defects is measured between their centers. The center of a defect lies on its longitudinal axis, which typically extends from the surface into the volume of the workpiece. In the simplest case, the diameter of a defect created with an ultrashort pulse laser is circular.

[0009] A key quality criterion for processing is the edge strength K of the processed element, particularly the edge of the desired element, from which an excess portion is typically removed. The aim is to achieve the highest possible edge strength. Unlike with thicker substrates, it is hardly feasible to perform any practical post-processing of the edges of ultrathin elements.

[0010] Ultrathin elements made of glass-based material are gaining increasing importance, for example as substrates for electronic components or as cover material for displays, especially hinged or foldable displays. Since such applications require particularly efficient manufacturing processes, the invention aims to provide a particularly economical method for producing ultrathin elements made of glass-based material, as well as corresponding ultrathin elements made of glass-based material and their use. The invention also includes a device for producing the aforementioned ultrathin elements made of glass-based material and a device for carrying out the method.

[0011] The problem is solved by the subject matter of the independent claims. Advantageous embodiments of the invention are specified in the respective dependent claims.

[0012] The process for manufacturing ultrathin elements from glass-based material includes the following steps:

[0013] Providing an ultrathin element made of glass-based material with a material thickness (d) of 5 to 100 pm,

[0014] Generating a focused laser beam using at least one ultrashort pulse laser with a laser wavelength in which the glass-based material element is at least substantially transparent, wherein the beam profile of the laser beam is shaped such that it has a laser preferred direction LVR, wherein the laser preferred direction LVR means that the extent of the laser beam in the direction of a provided dividing line is greater than perpendicular to it, and

[0015] Insertion of defects into the ultrathin element made of glass-based material with the focused laser beam along a predetermined dividing line, wherein adjacent defects have a distance A of 15 pm to 50 pm, wherein the distance A between the centers of adjacent defects is measured.

[0016] The described method is based on introducing damage into the ultrathin glass-based material using ultrashort pulse lasers, in particular laser filamentation. For the purposes of this description, ultrathin material is defined as a thickness d of the glass-based material of 5 to 100 pm.

[0017] In this process, the focused laser beam of a pulsed ultrashort pulse laser is directed at the element to be processed, or synonymously, the workpiece. The laser emits the laser beam with a wavelength A, whereby the workpiece, at least in the area where the laser beam hits, is at least substantially transparent to the laser's wavelength A. This means that the transmission of the workpiece at this point is greater than 85%, advantageously greater than 90%, and particularly advantageously greater than 95% at the laser wavelength A.

[0018] To nevertheless achieve an interaction of the laser beam with the workpiece material, an ultrashort pulse laser is used in accordance with the invention. With such a laser, the pulse width is very short, i.e., in the range of less than 1 ns, particularly in the range of a few ps to fs, especially in the range of 100 ps or 10 ps as the upper limit to 200 fs or 10 fs as the lower limit.

[0019] The interaction can generally be based on nonlinear optical effects, as described, for example, in WO 2012 / 006736 A2. Two nonlinear effects interact here: the self-focusing of the pulse due to the optical Kerr effect and its defocusing by the plasma generated by the laser in the material.

[0020] As an alternative to the Kerr effect, and also applied within the scope of the present invention, the damage can also be introduced by means of an elongated focus of the aforementioned ultrashort pulse laser. EP 3169635 A1 uses a Bessel beam with an axicon optic to extend the laser focus line during laser cutting. It states that the difference to a method based on the Kerr effect lies in the fact that refocusing the laser beam requires a modification of the refractive index of the workpiece material, in this case glass, whereas in the described case, there is induced absorption of the laser beam in the workpiece, which creates damage with a geometry that is more strongly coupled to the focusing optics than to the non-linear properties of the workpiece material.

[0021] Alternatively, and particularly advantageously within the meaning of the invention, it is also possible to focus the laser beam onto the ultrathin element using optics exhibiting aberrations, for example, chromatic and / or spherical aberrations. This is particularly advantageous because the ultrathin element represents a length range for the laser focus that can also be produced by a simple convergent beam path.

[0022] The laser irradiation causes damage to the workpiece. Damage includes any material modifications to the glass-based material and / or its destruction, particularly within the laser focus area. A well-known application of ultrashort pulse laser processing is laser cutting. In this process, damage is introduced into the glass-based material. By placing several damages next to each other at a distance A, a defined separation line is created, along which the glass-based material can be cut, for example, by applying voltage. This typically results in the formation of an edge that usually connects the main surfaces of the substrate.Assuming that the main surface of the substrate is defined as a surface in the x and y planes of the substrate, the separation line extends along this xy plane. The separation edge is formed by a plane whose longitudinal direction extends in the xy direction and whose height is determined by the substrate thickness in the z direction, also referred to here as d. A fundamental mechanism assumed here is that microcracks originating from the respective damage weaken the material. In the case of adjacent damage, the microcracks can connect to form a connecting line, thus enabling separation along this connecting or separation line.The separation line can also be understood as a predetermined breaking line or, as described, as a planned separation line, particularly if, after the damage is introduced, the workpiece is not yet separated and this separation only occurs through a later process step and / or by applying a mechanical force. The terms separation line and predetermined breaking line are used synonymously here. It is also possible that, after and / or during the insertion of the separation line, the element separates along the separation line spontaneously, i.e., without the application of any further mechanical force and / or thermal stress. In this case, it is referred to as "self-cleaving."

[0023] The inventors have recognized the advantages of using directed ultrashort pulse laser processing for machining ultrathin elements made of glass-based materials. This means that the laser beam profile has a shape with a preferred laser direction (LVR). The beam profile is designed to be expanded and / or elongated in the direction of the preferred laser direction (LVR). Viewed from above, the laser beam profile, particularly in the area of ​​interaction with the workpiece, does not deviate from a circular shape but is expanded and / or elongated in one direction. The main axis of this expansion and / or elongation is the preferred laser direction (LVR). According to the invention, this direction is arranged and / or aligned in the direction of the parting line.For example, the laser beam can be shaped like an oval and / or an ellipse, with its major axis aligned with and / or specifically lying on the separation line. As described in more detail below, this allows crack propagation to be controlled in the direction of the separation line, thus providing higher edge strength.

[0024] In other words, "laser preferred direction" (LVR) generally means that the extent of the laser beam in the direction of the dividing line is greater than perpendicular to it.

[0025] The applicable spacing A of adjacent defects for ultrathin glass-based elements is surprisingly different from that known for thicker elements. Generally speaking, it has been found that it is advantageous to use larger spacings for ultrathin elements in directional filamentation than those specified for elements of normal thickness.

[0026] For ultrathin elements made of glass-based material with a thickness d of 5 to 100 pm, a distance A or synonymous pitch of 15.0 to 50 pm has proven to be particularly advantageous.

[0027] With directed ultrashort pulse laser processing, the aforementioned range for distance A represents the optimal compromise between processing speed and edge strength for the aforementioned ultrathin elements made of glass-based material. As described in more detail below, the edge strength K decreases with both larger and smaller distances A. It has been found that this range offers the best edge strength for ultrathin elements made of glass-based material within the specified thickness range, while simultaneously providing a high processing speed and thus an efficient process thanks to directed ultrashort pulse laser processing. The reason for this maximum is unknown.

[0028] The aforementioned defects can, according to the invention, consist of a single defect or a group of defects. A group of 2 to 4 defects is advantageous, particularly a group of 2 to 3 defects and / or a group of 2 defects. The group of defects thus consists, so to speak, of a plurality of individual defects that are closely spaced, in particular closer than the distance A. As previously described, the distance A is measured from the center point of the defects. If the defects consist of groups of individual defects, the center point from which the distance A is measured is the geometric center of the respective group on the surface of the workpiece facing the laser. For the purposes of this description, the diameter F of a defect is determined by its maximum extent in the direction of the dividing line.If damage consists of a group of individual damages, the diameter F is the maximum extent of the group of individual damages in the direction of the preferred damage direction SVR.

[0029] Filamentous defects can be created in the workpiece with particular advantage. A filamentous defect, also referred to as a filament in this description, is generally understood to be an elongated, thread-like structure whose diameter is significantly smaller than its length. For the purposes of the present invention, the filamentous defect and / or the filament is a modification of the original material that arises from the irradiation of the ultrashort laser pulses and generally represents a mechanical weakening of the original material, or, particularly advantageously, a channel, which can especially be a hollow channel, and which penetrates at least one surface of the element. At least in some areas of the hollow channel, no original material is present. The hollow channel thus constitutes a cavity.Accordingly, it is possible and encompassed by the invention that the damage consists of a group of individual filament-shaped damages and / or filaments, in particular in the aforementioned number.

[0030] A particularly advantageous range for the material thickness d of the ultrathin glass-based element is from 5 pm to 50 pm, and most advantageously from 7 pm to 40 pm. Thus, particularly thin glass elements such as glass sheets, glass ribbons and / or glass wafers can benefit from the invention.

[0031] For the inventive method, it is particularly advantageous to select the distance A between adjacent defects in the range of 17 pm to 28 pm, especially in the range of 18 pm to 25 pm or in the range of 33 pm to 45 pm. The inventors have recognized that, surprisingly, two closely adjacent maxima for the edge strength of the aforementioned ultrathin elements occur within these ranges for the distance A. At the maximum in the smaller distance range A, somewhat higher edge strengths K can be achieved; however, the processing time increases due to the smaller pitch, assuming a constant laser repetition rate. At the maximum in the larger distance range A, the edge strengths are comparatively somewhat lower, but the processing time is shorter.This allows the user to select the optimal distance according to the required compromise between edge strength and processing speed. This also applies analogously to the entire aforementioned range for distance A.

[0032] An advantageous method is one of the aforementioned methods, wherein the defects have a diameter F and a preferred direction of damage SVR, where the preferred direction of damage SVR means that the extent of the defect in the direction of the dividing line is greater than perpendicular to it; preferably, F is from 0.2 pm to 5 pm, measured in the preferred direction of damage SVR. This applies both when the defect is a single defect and when it consists of a group of single defects.

[0033] Equally advantageous ranges for the upper limit of SVR are 3.5 pm or 3 pm.

[0034] It was described above that the laser beam, and in particular its focus, is designed to have a preferred laser direction (LVR). As a result of irradiating a material with a laser beam exhibiting a preferred laser direction (SVR), damage can be advantageously created in the glass-based material, exhibiting a preferred damage direction (SVR). The LVR and SVR directions are generally superimposed. However, their dimensions can differ. In particular, the extent of the laser beam can be greater than the extent of the damage in the glass-based material.

[0035] Even though the diameter F of a defect is mentioned here, it should be noted that in reality, laser-induced damage in a workpiece very rarely corresponds to a uniform shape and / or channel. This view is an idealized, simplified description. Local variations in diameter are quite possible along the axis of damage, i.e., the axis in the longitudinal direction of the damage. It is also possible, and encompassed by the invention, that the damage may have a different diameter at its beginning and / or end than in between.

[0036] As previously described, the actual cause of the maxima in edge strength as a function of distance A is unknown. However, it can be assumed that directed ultrashort pulse laser processing with a laser preferred direction (LVR) generates LVR damage in the workpiece with a preferred SVR damage direction. Consequently, crack propagation in the direction of the preferred SVR damage direction occurs statistically significantly more frequently and / or is more probable than in the direction of the substrate material. The cracks in the preferred SVR damage direction between adjacent damages merge to form the parting line. Beyond a certain distance, the probability of the cracks merging increases, and they presumably propagate into the substrate material, thus resulting in a reduced edge strength K.

[0037] It should be emphasized here that, in the context of this description, "separation" refers both to the independent separation of parts of the element ("self-cleaving") and to separation by applying an additional force, be it mechanical breaking force and / or thermal stress. The latter can be advantageous for the efficient industrial processing of pre-separated elements.

[0038] A particularly advantageous method is one in which the damage extends from a top surface to the opposite bottom surface of the glass element. Thus, the damage advantageously extends completely through the thickness d of the glass-based material element. Alternatively, it is of course also possible, and encompassed by the invention, that the damage terminates within the volume of the element, forming a kind of blind hole.

[0039] An advantageous embodiment of the invention provides that at least one initial crack in the preferred direction of damage SVR is associated with each damage, with an initial crack length IRL, determined as the maximum crack length measured in transmitted light, starting at the damage and extending to the tip of the initial crack.

[0040] For the purposes of this description, an initial crack is understood to be a crack visible in a transmitted light image taken with an optical microscope. This clearly distinguishes it from a microcrack, which is not visible in this setup. It is assumed that the subsequent application of a high-energy laser beam with a laser-preferred direction (LVR) to the filament induces such extensive material damage that the glass-based material cracks. In principle, the formation of initial cracks and their respective lengths depend on the properties of the glass-based material, the properties of the laser, and the interaction between these two. For example, strong initial crack formation, i.e., the formation of numerous and / or long cracks, is favored by a material with a high coefficient of thermal expansion and low fracture toughness.Repeated exposure of a given volume of material to laser radiation, typically achieved through a rapid sequence of ultrashort laser pulses (a so-called burst), also leads to increased cracking. High initial cracking is further promoted by high densities and density gradients of the energy introduced into the glass-based material by the laser.

[0041] The initial crack generated in this invention can be measured optically, in particular its initial crack length IRL. Depending on how the beam profile with laser preferred direction LVR is configured, the initial crack can be located on both sides of the damage in the direction of and / or on the dividing line, or only on one side. The latter is particularly achievable with a laser beam that is non-axially symmetrical transverse to the laser preferred direction LVR, the former with a laser beam that is axially symmetrical transverse to the laser preferred direction LVR.

[0042] The initial cracks of adjacent defects, facing each other, are highly likely to merge. Crack propagation towards the volume of the element away from the separation line is advantageously suppressed. This allows for particularly high edge strengths of the element along the separation line.

[0043] A particularly advantageous embodiment of the method is one in which the initial crack length (IRL) of the initial cracks in the preferred damage direction (SVR) is from 6 pm to 16 pm, especially from 8 pm to 12 pm or from 9 pm to 11 pm. This means, in particular, that the pitch (A) and the initial crack length can be coordinated to provide the best compromise between edge strength and processing speed.

[0044] A particularly advantageous embodiment of the method is one in which a distance-damage relationship Q is established, wherein Q is determined by Q = A - (F + 2 ■ IRL), and Q lies in a range from -4 pm to +40 pm, in particular from -1 pm to +30 pm or from -0.2 pm to 30 pm or from 2.0 pm to 10 pm.

[0045] This is based on the surprising finding that the highest edge strengths are achievable when the initial cracks overlap and / or are located at a limited distance from each other. Advantageous ranges for Q are particularly those where the lower limit is in the range of -1 pm or 0 pm and the upper limit is in the range of 10 pm to 20 pm. These ranges are especially relevant in combination with the aforementioned values ​​for IRL. An upper limit for Q of 10 pm is particularly advantageous.

[0046] For beam shapes symmetrical in the laser's preferred direction (LVR), it is particularly advantageous if two initial cracks are located on both sides of the damage or if there is a slight overlap. An overlap is indicated by a negative numerical value for Q.

[0047] It should be noted here that an initial crack does not necessarily have to extend through the entire thickness d of the workpiece. Typically, it is only present in a partial area in the direction of the laser beam. Transmitted light measurement measures the projection of the initial crack onto the workpiece surface, thus determining its maximum length IRL (in real time).

[0048] The initial cracks can connect as described above. It is also possible that further induced microcracks may develop along the initial cracks and / or that the initial cracks may extend. With sufficient crack formation, it is possible for the workpiece, in this case the ultrathin element made of glass-based material, to separate spontaneously along the separation line. However, it is also possible, and encompassed by the invention, for the separation of the elements to occur by applying a further mechanical force and / or stress. This case is explained in more detail below.

[0049] Initial cracks can be advantageously introduced by a sequence of successive ultrashort laser pulses, a so-called burst. The burst used can advantageously consist of 2 to 6 individual pulses, in particular 4 individual pulses.

[0050] Self-cleaving can be achieved particularly in regions where Q is up to approximately 10 pm. The invention thus provides the possibility of selecting whether the glass-based material element is separated by self-cleaving or, depending on the application, whether a pre-separated element is provided by ultrashort pulse laser processing, which can later be separated by a further separation process, for example, by applying a mechanical force and / or tension.

[0051] A further particularly advantageous embodiment of the method comprises separating the element made of glass-based material along the intended separation line, whereby a free fracture zone with a length g of 0.1 pm to 40 pm is generated between damages along this separation line, or the length g lies in the range 0.1 pm < g < F + 2 ■ IRL, advantageously in the range 0.1 pm < g < F + IRL, particularly advantageously in the range 0.1 < g < (F + IRL) / 2.

[0052] A clearance zone within the meaning of the invention is an edge of the separated element, in particular of the good part, which lies on the separation line and / or runs at least substantially parallel to it. The clearance zone adjoins the respective initial damage and, if applicable, initial cracks. As described above, it can be understood as an extension of the initial damage and / or initial cracks. The clearance zone typically has a surprisingly smooth edge. The clearance zone lies between the damage and / or the initial cracks. It is evident that a clearance zone is present when Q > 0, meaning there is no overlap of the initial damage and / or initial cracks. It has proven particularly advantageous if the clearance length g is also adjusted depending on the initial crack length.The clearance length up to twice the initial crack length IRL has proven advantageous, to which in particular the diameter F of the damage can be added, i.e. up to (F + IRL) ■ 2, particularly advantageous up to the initial crack length and / or F + IRL, particularly advantageous up to half the initial crack length and / or (F + IRL) / 2.

[0053] Within these areas, in the embodiment with a fracture zone at the dividing line, a particularly high edge strength of the ultrathin element can be achieved. As already mentioned, the glass-based material of the ultrathin element comprises, in particular, glass and / or glass-ceramic. Specifically, it consists of these.

[0054] A particularly advantageous embodiment of the method comprises separating the glass-based element along the dividing line, wherein the edge strength K of the element is greater than 170 MPa at least on one side of the dividing line, advantageously from 170 to 400 MPa, or from 180 to 380 MPa, or from 180 to 250 MPa; an edge strength K in the range of 2.5 ■ d < K < 6 ■ d is particularly advantageous. This inequality merely represents a correlation, the pure numerical value of which is applicable. The numerical values ​​are to be entered dimensionlessly, with d in pm and K in MPa. As described, d denotes the material thickness of the ultrathin element. It has been found that, as expected, the edge strength increases with the thickness d of the element. Within the range specified herein for the thickness d, it lies within the range indicated in the inequality.

[0055] The specified edge strength can be measured as described in DE 10 2014 110 855 A1. According to this patent, the testing of the fracture strength of planar specimens made of brittle material, in particular glass sheets, requires that the specimens have a first side surface and a second side surface, as well as at least one edge, and that the first side surface is opposite the second side surface. The test relates to fractures originating from this edge of the specimen under a tensile stress s, whereby the first side surface at the edge to be tested is subjected to a tensile stress s along the edge in a section of the specimen by bending the specimen in this section so that it is bent along the edge, and by pressing the specimen in this section against the surface of a dimensionally stable gauge with a defined curvature.so that the curvature of the gauge surface is imposed on the section to be inspected, whereby a gauge surface with a first bending radius R is used and the tensile strength of the specimen is checked under the mechanical tensile stress s corresponding to this bending radius R, and this check is repeated with successively decreasing bending radius R and associated increasing tensile stress s until the specimen breaks, and it is evaluated at which tensile stress s or at which bending radius the specimen broke. In particular, it can also be determined whether the specimen broke from the edge to be inspected.

[0056] Besides edge strength, the yield, here called Yield Y, is also a measure of the quality of the produced, i.e., separated, element made of glass-based material. Yield Y is a statistical measure that includes the reject rate of separated elements. To determine Yield Y, a predetermined number of elements produced according to the description herein are processed with an ultrashort pulse laser and then separated. The produced elements are then classified as good or reject. Yield Y is defined by

[0057] Y = 1 - ( Nbad / Nall ) , where Naii represents the total number of elements examined and Ngood the number of elements deemed good. The following relationship naturally holds:

[0058] Ngood — Nall — Nbad, where Nbad represents the number of elements rated as rejects. An element is rated as rejects, in particular, if it exhibits cracking away from the parting line, for example, if cracks run in the direction of the element's material, i.e., the desired element obtained after separation. Nbad / Naii thus represents the reject rate.

[0059] The process quality of the elements produced according to this description from glass-based material and / or the edge produced at the parting line is a combined measure of economic efficiency, represented by the yield Y, and product quality, represented by the edge strength K. The process quality can be determined by the quality factor R:

[0060] R = KY .

[0061] A high R-value indicates a stable process. In other words, a high R-value suggests a high probability of achieving high edge strength along the parting line.

[0062] A particularly advantageous aspect of a method according to the invention is that the glass-based material element is separated along the parting line, wherein the product R of the element's edge strength K and yield Y is greater than 100, advantageously greater than 150, and particularly advantageously between 100 and 400 or between 150 and 300, at least on one side of the parting line. This means, in particular, that especially good values ​​for R can be achieved in the aforementioned pitch range. This underscores that the invention provides a particularly efficient method for processing ultrathin glass-based material elements. A particularly advantageous method is one in which the glass-based material element is in the form of a planar substrate, especially a glass and / or glass-ceramic sheet, and wherein the parting line is preferably inserted into the edge regions of the planar substrate.

[0063] This applies in particular to the processing of individual elements at corresponding processing stations. The individual elements are separated sequentially at the processing stations. This means that a glass element is fed into the processing station and processed. The processed element is then transported further, and an unprocessed element is fed into it.

[0064] It is of course possible, and encompassed by the invention, that the dividing line can be introduced at any point on the element. However, separating the edge region of the elements, especially the edge region of ultra-thin glass sheets, is particularly advantageous.

[0065] An alternative advantageous embodiment of the method comprises the element being made of glass-based material as a continuous glass ribbon with a predetermined glass thickness d. A particularly advantageous method provides that the glass-based material is made as a continuous glass ribbon with a predetermined glass thickness d, wherein at least one longitudinal dividing line is produced at least along the length of the glass ribbon with an edge having a thickened border, and wherein the border is cut off along the longitudinal dividing line to form an edge, and / or wherein at least one transverse dividing line is produced transversely to the glass ribbon, and wherein glass sheets are cut off at the transverse dividing line running transversely to the glass ribbon to form edges.

[0066] The inventive method thus makes it possible to separate one or both edges on the respective edge side of a continuous ultrathin glass ribbon. Alternatively or additionally, the inventive method makes it possible to separate a continuous ultrathin glass ribbon transversely into ultrathin glass sheets. The resulting edges exhibit improved edge strength.

[0067] In a further advantageous embodiment, the method provides that at least one longitudinal dividing line is inserted in the hot zone of the glass ribbon. The ultrashort pulse laser processing with the parameters mentioned herein makes it possible to process the edge regions of the glass ribbon of ultrathin glasses shortly after it leaves the melting unit, i.e., in the hot zone, particularly at temperatures above or, especially advantageously, slightly below the transformation temperature Tg of the glass, particularly in the range of 50 K, 20 K, 10 K, or 5 K below Tg.

[0068] Alternatively, at least one longitudinal dividing line can be inserted in the cold zone of the glass ribbon, the glass ribbon being advantageously cooled at a rate of 10 Kelvin / s or greater, advantageously at 20 Kelvin / s or greater, and particularly advantageously at 40 Kelvin / s or greater. Cooling rates of 100 Kelvin / s or greater, 150 Kelvin / s or greater, or 200 Kelvin / s or greater are particularly advantageous. It is particularly advantageous to use a cooling rate in the range of (1 / d) ■ 4500 Kelvin / (s ■ pm) to (1 / d) ■ 9000 Kelvin / (s ■ pm), where d denotes the thickness of the glass ribbon.

[0069] The ultrathin glass ribbon is rapidly drawn using a down-draw process, specifically at speeds ranging from 0.5 meters per minute to 50 meters per minute, as described above. However, the process is not limited to down-drawing. Overflow fusion drawing or other methods suitable for producing thin glass ribbons are also possible, including redrawing previously drawn glass elements. In one embodiment of the down-draw process, the insertion of the parting lines with the described defects can occur after the glass ribbon is deflected into a horizontal position. The glass ribbon is cooled rapidly, and cooling rates as mentioned above can be applied.

[0070] To ensure reliable and easy separation of the edges from the glass ribbon and the separation of individual glass panes, it is particularly advantageous to cool the glass ribbon before inserting the predetermined breaking lines in the region of the glass transition temperature, especially at a temperature below the softening point, and most advantageously at a temperature below the glass transition temperature Tg. To optimize the process, cooling the glass ribbon can optionally also take place during and / or after inserting the predetermined breaking lines.

[0071] In one possible embodiment of the process, cooling takes place in a cooling oven, particularly with heating elements, or by blowing or spraying a cooling fluid, particularly air, other gaseous media, or an aerosol. In the latter case, the cooling rate can be adjusted / determined, for example, by controlling the flow rate of the cooling fluid to the process parameters of glass ribbon temperature and feed rate, in order to prevent undesirable stresses in the glass ribbon.

[0072] The laser beam can be shaped into a Bessel beam, particularly using beam-shaping optics. Gaussian beams are also possible with optics exhibiting spherical and / or chromatic aberration, as are hybrid forms of both.

[0073] As described above, a key aspect of the described method is directed ultrashort pulse laser processing. In particular, the beam profile of the laser beam is shaped in such a way that a laser preferred direction (LVR) is present.

[0074] In particular, the laser beam can be shaped in such a way that, in its focus area, the extent of the laser beam in the direction along the predetermined breaking line is greater by a factor in the range of 1.3 to 5, and especially by a factor in the range of 1.5 to 4, than the extent in the direction perpendicular to the dividing line.

[0075] This allows, as described above, the formation of an effective preferred damage direction (SVR) in the workpiece in the direction of the parting line. In particular, the optics can generate a beam profile with a lateral laser preferred direction. It is especially advantageous if the beam profile of the laser beam, particularly the extent of the laser beam and / or the damage in the direction of the parting line, has a shape selected from the group consisting of elliptical, lanceolate, teardrop, diamond-shaped, dumbbell-shaped, wedge-shaped, or spot-shaped beam profiles, or a beam profile with a main beam and at least one satellite with lower intensity. The latter and the oval-shaped profile have proven particularly advantageous in the context of this description. A split beam and / or a central beam with two satellites are also advantageous.

[0076] The beam profile with at least two mutually spaced intensity maxima can, for example, be formed by a double line focus with beam extension due to spherical aberration.

[0077] The profiles described make it possible to create almost any contour with particularly high edge quality or edge strength after separating the edges and singulating the ultra-thin elements made of glass-based material.

[0078] In one possible embodiment of the method for producing ultrathin glass sheets, the dividing line is first inserted transversely to the glass ribbon, thus creating the transverse dividing lines, and then longitudinally on both sides of the glass ribbon with edges that each have a thickened border, to create the longitudinal dividing lines. In this way, the glass ribbon is held together by the borders after the transverse dividing lines have been inserted, thereby providing mechanical stability. In another possible embodiment, the moving device for moving the ultrathin glass ribbon is preferably equipped with at least one pressure roller, a pressure edge, or a suction device to fix the position of the glass ribbon within the laser's focus area.This fixes the glass ribbon in relation to the position of the ultrashort pulse laser focus and the arrangement of the separation line from defects, preventing the glass ribbon from drifting out of the laser beam's focus area. In particular, this fixation also increases the speed of the manufacturing process while avoiding the aforementioned disadvantages, thus positively impacting the process's cost-effectiveness.

[0079] The separation of the edges at the longitudinal predetermined breaking points and / or the separation of ultra-thin glass sheets by separating at the transverse separation lines running perpendicular to the glass ribbon can be carried out either by self-cleaving or advantageously with mechanical assistance, i.e. as described above by applying a mechanical force and / or tension.

[0080] An advantageous method accordingly provides that the final separation of the edges at the longitudinal separation lines and / or the separation of glass panes by separation at the transverse separation lines running perpendicular to the glass ribbon is carried out mechanically.

[0081] The aforementioned free-break area occurs particularly when using mechanical cutting. Both self-cleaving and mechanical cutting can be used in processing a glass ribbon. This enables, in effect, a continuous process. It is especially advantageous if the glass ribbon is wound onto a reel after the edges have been cut off.

[0082] The process for producing ultrathin glass sheets and / or glass ribbons according to this disclosure also enables particularly high cutting speeds, especially up to 50 m / s, and particularly advantageously up to 30 m / s or up to 20 m / s. The process is particularly low in particles and results in exceptionally stable edge strength, thus leading to increased predictable yields.

[0083] The reduced manufacturing costs and the stable quality of the ultrathin elements made from glass-based material achieved with this process make it particularly economical. This also makes it possible, in particular, to supply ultrathin glass on a roll on an industrial scale.

[0084] Glass sheets and / or glass strips with a glass thickness of 5 pm to 100 pm, in particular from 10 pm to 50 pm or from 25 pm to 40 pm, were produced using this method. The glasses used had, in particular, a coefficient of thermal expansion greater than 3 ppm / K, and especially greater than 6 ppm / K.

[0085] The invention encompasses not only the described method but also ultrathin elements made of glass-based material. All statements and / or embodiments relating to the method also apply, when applied analogously, to the ultrathin elements made of glass-based material.

[0086] An element encompassed by the invention is an ultrathin element made of glass-based material with a thickness d in the range of 5 pm to 100 pm, which has damage along at least one edge having a distance A of 15 pm to 50 pm, in particular of 7 pm to 40 pm, or of 17 pm to 28 pm, in particular of 18 pm to 25 pm, and / or of 33 pm to 45 pm.

[0087] The ultra-thin element made of glass-based material is particularly advantageous when available as a glass sheet or as a glass roll.

[0088] As described in connection with the process, the diameter F of the defects, measured on the top surface of the element in the direction of the preferred defect direction SVR, is typically from 0.2 pm to 5 pm. The aforementioned particularly advantageous ranges also apply here. Because the element was separated along the dividing line, it can be assumed that the defects open along the preferred direction and thus the diameter F of the defects corresponds to the previously described diameter F in the preferred defect direction SVR.

[0089] A particularly advantageous feature is an ultrathin element made of glass-based material, wherein an initial crack follows the damage along the edge with an initial crack length IRL. Advantageously, the initial crack length IRL is from 5 pm to 16 pm, especially from 8 pm to 12 pm or from 9 pm to 11 pm.

[0090] The shape of the initial cracks has already been described. These can be observed or identified in a microscopic image of the edge, as they represent a characteristic area at the edge. The initial crack length (IRL) of the separated element is the maximum width of this characteristic area, measured on one side of the damage.

[0091] A particularly advantageous feature is an ultrathin element made of glass-based material with a distance-damage relationship Q, where Q is determined by

[0092] Q = A - (F + 2 ■ IRL), and Q lies in a range from -4 pm to +40 pm, particularly from -1 pm to +30 pm or from -0.2 pm to 30 pm or from 2.0 pm to 10 pm. Likewise, suitable lower limits are 1 pm or 0 pm with suitable upper limits of 10 pm or 20 pm. An upper limit of Q of 10 pm is particularly advantageous.

[0093] The parameter Q has already been discussed in detail in the context of the procedure. These explanations also apply analogously to the element.

[0094] Advantageously, such an element is further developed by an ultrathin element made of glass-based material, wherein a fracture zone with a web width g of 0.1 pm to 40 pm is located between damages.

[0095] The web width g is particularly advantageous in the range 0.1 pm < g < F + 2 IRL, very advantageous in the range 0.1 pm < g < F + IRL, and especially advantageous in the range 0.1 < g < (F + IRL) / 2. Initial damage, damage length, and the clearance fracture zone have already been discussed in detail. All statements made above also apply to the ultrathin element. The clearance fracture zone can also be clearly identified as such by light microscopy or by imaging the edge, especially since it produces a typical edge pattern. The edge in the clearance fracture zone is usually very smooth, or at least significantly smoother than in the areas of damage and / or initial cracks. "Smooth" in this context means, in particular, that the roughness is lower compared to the aforementioned areas.

[0096] The resulting ultrathin element made of glass-based material advantageously has an edge with defects and an edge strength K of more than 170 MPa, particularly advantageously from 170 to 400 MPa or from 180 to 380 MPa or from 180 to 250 MPa, and particularly advantageously an edge strength (K) in the range of 2.5 ■ d < K < 6 ■ d.

[0097] Descriptions of these explanations were already provided in connection with the procedure above and naturally also apply to the element itself.

[0098] The invention also includes a device for carrying out the above-described method and / or a device for producing a above-described ultrathin glass element.

[0099] Based on the description provided herein, it is readily possible for a person skilled in the art to manufacture such a device.

[0100] These ultrathin glass sheets and glass-based elements, produced according to the described method, can be used for a wide variety of applications. They are particularly advantageous as insulating intermediate substrates or spacers for electronic components, for encapsulating optoelectronic components, as substrates for thin-film cells such as thin-film batteries or thin-film solar cells, as cover elements for displays, especially hinged and / or foldable displays, or as substrates or composite substrates for displays and microfluidic cells.

[0101] The diverse applications benefit from properties such as chemical, temperature change and heat resistance, gas tightness, high electrical insulation capacity, adapted coefficients of expansion, flexibility, high optical quality and light transmission, as well as the high surface quality with very low roughness of the two ultra-thin glass sides, and the high edge strength of the glass-based material elements achieved through the separation process.

[0102] The invention is explained in more detail below with reference to the accompanying figures, without limiting the invention. The figures and the accompanying description also represent exemplary embodiments. Unless dimensions are indicated, the figures are schematic representations. The dimensions, proportions, and / or shapes depicted therein may differ from the actual objects.

[0103] Fig. 1 shows a schematic device for the production of ultra-thin glass sheets.

[0104] Fig. 2 shows a first group of schematic beam profiles of the beam-shaping optics with laser preferred direction LVR.

[0105] Fig. 3 shows a second group of schematic beam profiles of the beam-shaping optics with laser preferred direction LVR.

[0106] Fig. 4 shows an arrangement for separating the glass ribbon into individual glass panes and for cutting the edges.

[0107] Fig. 5 shows damage without a preferred direction according to the prior art.

[0108] Fig. 6 shows damage with preferred SVR direction. Fig. 7 shows damage with preferred SVR direction and initial cracks.

[0109] Fig. 8 shows damage with preferred direction of damage, initial cracks and areas of free breakage.

[0110] Fig. 9 is a photographic image of damage with initial cracks in an ultrathin glass element in top view.

[0111] Fig. 10 is a photographic image of damage with initial cracks in top view.

[0112] Fig. 11 shows the section through an element and damage.

[0113] Fig. 12 shows a top view of an element with separation lines and damage with preferred damage direction SVR.

[0114] Fig. 13a shows a top view of an element with damage along a dividing line.

[0115] Fig. 13b shows a top view of an element with a damaged edge.

[0116] Fig. 13c shows a top view of an element with an edge with damage and a break-off area.

[0117] Fig. 14 is a diagram of the edge strength K as a function of the pitch.

[0118] Fig. 15 is a diagram of the product R=YK as a function of the pitch.

[0119] Fig. 16 shows a photographic image of damage in cross-section through the element.

[0120] Fig. 17 shows a schematic device for the production of ultrathin glass on a roll.

[0121] Fig. 1 schematically shows an embodiment of a device 1 for producing ultrathin glass sheets 2 with a predetermined glass thickness d in the range of 5 pm to 100 pm. A continuous glass ribbon 4 is drawn from a glass melt 10 through a downwardly directed, slot-shaped nozzle 6, which is part of a hot-forming device 8. Here, the so-called down-draw process is preferably used as the hot-forming method for ultrathin glass ribbons, and the insertion of parting lines 12 with defects 14, i.e., the ultrashort pulse laser processing, is advantageously carried out directly during the down-draw process, particularly advantageously after deflecting the glass ribbon 4 into the horizontal position. The process is also applicable in principle to other glass-based materials. The very small thickness d of the ultrathin glass ribbon is achieved by the down-draw process. Other manufacturing processes are also possible and encompassed by the invention.It is also possible to perform ultrashort pulse laser processing in other areas, for example closer to the hot area.

[0122] Controlled predetermined breaking or separation lines 12 from defects 14 are introduced into the glass ribbon 4 using at least one ultrashort pulse laser 16. In this example, the laser pulse is generated by a beam-shaping optic 18, creating a beam with a focal region 20 extended in the laser propagation direction. This focal region 22 extends through the glass ribbon 4. In particular, the beam-shaping optic 18 can focus the laser beam 20 to increase the power density within the glass. The intensity distribution, and thus the shape of the defects 14, can be precisely controlled via the beam-shaping optic 18 such that they exhibit a preferred direction of damage propagation (SVR). As previously described, the laser beam 20 advantageously has an elongated focal region in the direction of the thickness d of the glass ribbon 4.This is also possible with optical devices other than Bessel beam optics, for example through spherically and / or chromatically aberrated systems.

[0123] The focus area is advantageously set to be longer than the glass thickness d in order to produce deep, spaced-apart damage 14 in a predetermined volume of the glass strip 4, advantageously from one surface 51 to the opposite surface 52 of the glass strip 4, that is, preferably over the entire thickness d of the glass strip 4.

[0124] For example, an Nd:YAG laser with a wavelength of 1064 nm, an average power of 12 W (at 1064 nm, 100 kHz, 1 pulse per burst), a repetition rate of 100 kHz, a burst frequency of 50 MHz, and a pulse duration of approximately 10 ps (at 1064 nm and 100 kHz) is suitable as an ultrashort pulse laser for the purposes of the invention. Other lasers, especially those with higher powers, are of course equally applicable.

[0125] According to another embodiment, a 1030 nm Yb:YAG laser can be used. Generally, the lasers can be used as frequency-doubled (SHG) or frequency-tripled (THG) versions. According to one embodiment, the pulse lengths are in the range of 300 fs to 20 ps, ​​or in the range of 400 fs to less than 10 ps. The repetition rates can be in the range of 50 kHz to 1 MHz, preferably 100 kHz to 500 kHz.

[0126] Pulse energies can exceed 100 pJ, 200 pJ, or 400 pJ. The number of burst pulses was less than 2, less than 4, or less than 8.

[0127] It is also possible, and covered by the invention, that no burst is used. In that case, a single pulse is sufficient to create the damage in the ultrathin glass.

[0128] In one embodiment, a laser was used that generated pulse energy of up to 8 mJ at pulse repetition frequencies of 25 kHz, up to 4 mJ at 50 kHz and up to 2 mJ at 100 kHz.

[0129] Furthermore, the device 1 for producing ultrathin discs from glass-based material 2 advantageously comprises a movement device 24, for example, transport rollers, in particular pull rollers, for moving the glass strip 4, the ultrashort laser 16 and / or the beam-shaping optics 18 for positioning the laser beam 20 along a predetermined path of the predetermined fracture lines 12 on the glass strip 4. The laser beam 20 can be guided over the glass strip 4, or the glass strip 4 can be guided past the laser beam 20. A combination of both variants is also possible. To move the laser beam 20 perpendicular to the direction of movement of the glass strip 4, for example, a galvanometer scanner can be used, or a deflecting mirror can be transported on a movable axis transverse to the glass strip, or the laser 16 and / or the optical device 18 can be moved.

[0130] As will be explained in more detail with reference to Fig. 4, transverse dividing lines 121 are formed perpendicular to the glass strip 4 and longitudinal dividing lines 122 are formed on both sides along the glass strip 4. The glass strip 4 usually has edges with a thickened border 13, which are separated by the longitudinal dividing lines 122 and / or whose separation is at least prepared.

[0131] It can also be utilized that the scatter of the fracture force at the edges produced by the laser-assisted method according to this disclosure can be reduced by a cooling rate adapted to the glass thickness. The device 1 for producing glass sheets 2 thus further comprises a cooling device 26, which is arranged and configured such that it cools the glass ribbon 4 before the insertion of the filament-shaped defects 14 into the glass ribbon 4 at a cooling rate that is selected depending on the predetermined glass thickness d, with the cooling rate increasing as the glass thickness decreases. Advantageously, the cooling of the glass ribbon 4 before the insertion of the dividing lines 12 takes place in the region of the glass transition temperature, preferably at a temperature below the softening point, and particularly preferably at a temperature below the glass transition temperature.

[0132] In an advantageous embodiment, the cooling of the glass ribbon 4 is carried out in a cooling oven 27, in particular in a controlled manner using heating elements. If necessary, homogeneous cooling can also be supported by blowing or spraying with a cooling fluid, in particular with air or an aerosol. According to one embodiment, the device 1 for producing glass sheets 2 further comprises a separating device 28, which is arranged and configured such that it advantageously separates the edges 13 along the longitudinal predetermined breaking points 122, forming edges 30, and the glass sheets 2 by separating them along the transverse breaking lines 121 running perpendicular to the glass ribbon 4, forming further edges 30. The separating device can thus include an arrangement with a convex roller, which is guided over the predetermined breaking lines.Alternatively, a heat source, such as a laser, can be used to induce thermal stresses at the predetermined breaking line. In some cases, however, no mechanical action may be required to separate the glass at the predetermined breaking lines.

[0133] In a further advantageous embodiment, the movement device 24 for moving the glass ribbon 4 is equipped with at least one pressure roller, a pressure edge, or a suction device for fixing the axial position, or the position of the glass ribbon 4 in the beam direction within the focus area, so that the glass ribbon 4 is not distorted with regard to the singulation of the glass sheets 2 and the separation of the edges 13, which could impair the shape and edge quality of the individual glass sheets 2. In particular, the fixing also allows the speed of the manufacturing process to be increased while avoiding the described disadvantages, which has a positive effect on the economic efficiency of the process. In the figure shown in Fig.In the example shown in Figure 1, a pair of pressure rollers 15 is shown as a device for fixing the vertical position of the glass ribbon 4, which determine the position of the glass ribbon in the direction of the laser beam 20 near the point of impact of the ultrashort pulse laser 16.

[0134] As described above, the inventive method for producing glass panes 2 is based on directed ultrashort pulse laser processing. In this embodiment, the beam profile is adjusted by a corresponding beam-shaping optic 18 such that the intensity profile of the laser beam is extended in the direction of the respective dividing line or predetermined breaking line 12. The extent of the laser beam in the direction of the dividing lines 12 is thus greater than transversely, and in particular perpendicularly, to them. In this way, the amount of radiation integrated along the dividing lines 12 is greater than along a line running perpendicular to the dividing line 12 and crossing the center of the beam 20. In other words, the beam-shaping optic preferably generates a beam with a cross-section that is more extended in the direction of the linearly arranged defects 14, the so-called laser preferred direction LVR, than transversely to them.

[0135] The individual defects 14 run transversely in their longitudinal direction, preferably perpendicular to the surface 51, 52 of the glass ribbon 4, following the propagation direction of the laser beam 20. For this purpose, the beam-shaping optics 18 is preferably adjustable with respect to a larger beam bundle cross-sectional area and the direction of the larger cross-sectional area is preferably guided to the course of the linearly arranged defects 14.

[0136] In the direction of propagation of the laser beam, and thus in the direction of the thickness d of the glass band 4, the intensity profile of the laser beam is advantageously sufficiently energetic, at least within the glass band 4, to exceed the damage threshold. This means that the laser beam can, so to speak, have the shape of a sword within the glass band 4. To achieve such focusing, for example, a lens with spherical aberration, one or more axioms, or a diffractive optical element (DOE), or combinations thereof with other optical elements, are suitable as beam-shaping optical elements. Other optical configurations are also possible as described above and are encompassed by the invention. In particular, the use of cylindrical lenses and / or special lenses is possible and intended.

[0137] The laser preferred direction LVR can be imposed by suitable optical elements, for example by cylindrical lenses and / or an arrangement of cylindrical lenses. Other suitable optical arrangements are also possible and encompassed by the invention.

[0138] In a further advantageous embodiment of the method, the beam-shaping optics 18 generate an asymmetric beam profile with a lateral preferred direction. Fig. 2 shows various possible beam profiles in a top view. Part (a) shows an elliptical beam profile 32. This is aligned such that its long semi-axis is aligned along the respective predetermined breaking line and thus in the laser preferred direction LVR. Accordingly, the extent L of the beam profile along the predetermined breaking line is greater than the extent LS perpendicular to the breaking line. The laser preferred direction LVR is also shown in Fig. 2.

[0139] Partial image (b) shows a teardrop-shaped beam profile 33. In the embodiment according to partial image (c), the laser beam is split into two beams. The beam profile 34 therefore has two spaced-apart beams in the form of a double beam. Partial image (d) shows a diamond-shaped beam profile 35, partial image (e) a dumbbell-shaped beam profile 36, and partial image (f) a wedge-shaped beam profile 37. Finally, partial image (g) shows a beam profile 38 with a main beam and a weaker or smaller satellite beam.

[0140] The extent L of the beam profiles in the laser preferred direction LVR is composed, in the case of multi-part beam profiles, here those according to partial image (c) and (g), of the diameters of the respective partial beams and their distance.

[0141] The embodiments of partial images (b), (f), and (g) have in common that they are not only more extended in the laser's preferred direction LVR than perpendicular to it, but are also asymmetrical with respect to a mirror axis perpendicular to the laser's preferred direction LVR. This can be advantageous because asymmetrical conditions also exist during the insertion of the filaments, since, unlike the portion of the predetermined breaking line already swept over by the beam in the feed direction, no damage is present upstream of the laser beam. Therefore, advantageously, without being limited to the specific examples, it is provided that the damage 14 is introduced with a laser beam 20 that has an asymmetrical beam profile with respect to a reflection perpendicular to the feed direction.

[0142] Figure 3 shows further particularly advantageous beam profiles. Partial images (a) and (f) correspond to those of Figure 2. Partial image (g) shows a teardrop-shaped profile and partial image (h) a heart-shaped one.

[0143] The partial images (c) and (g) of Fig. 2, as well as the partial images (i) and (j) of Fig. 3, show beam profiles that have proven to be particularly advantageous. These are multi-part beam profiles, in the case of partial images (i) and (j) of Fig. 3 with constrictions at their respective ends lying on the dividing line 12. These constrictions allow, in particular, the creation of damage 14 with initial cracks 60, which are arranged on both sides of the damage on the dividing line 12.

[0144] The multi-part beam profiles corresponding to partial images (c) and (g) of Fig. 2 and partial images (i) and (j) of Fig. 3 can, in particular, generate a group of defects as previously described, specifically as defect 14. Generally, as also already described, the shape of the defects in the element and / or workpiece follows the shape of the laser beam profiles and / or is at least similar to them. LVR and SVR, in particular, lie at least substantially on top of each other.

[0145] The examples shown in Fig. 2 and Fig. 3 result in a controllable shape with higher geometric accuracy of the resulting separation lines 12 from damage 14, coupled with higher edge strength after the removal of the borders 13 and optionally the singulation of the glass panes 2.

[0146] Fig. 4 shows an arrangement for separating the ultrathin glass ribbon 4 into individual glass sheets 2 and for separating the borders 13. Fig. 4 can also be interpreted as a section of Fig. 1.

[0147] In an advantageous embodiment of the method for producing glass sheets 2, the sequence of inserting the dividing lines 12 is determined by the process technology: first transversely to the glass strip, thereby creating the transverse dividing line 121, and then longitudinally on both sides to the glass strip with edges that each have a thickened border, to create the longitudinal dividing lines 122, because the glass strip 4 is then still held together by the borders 13 and thereby mechanically stabilized.

[0148] For this method, a motion device 24 for transporting the continuously drawn glass ribbon 4 is preferably provided, which in the illustrated example comprises a conveyor belt 240. To insert the dividing lines 12, several ultrashort pulse lasers 16 can also be advantageously used in general, without being limited to the illustrated example, wherein at least one first ultrashort pulse laser 16 inserts the transverse dividing lines 121 and at least one second ultrashort pulse laser 16 inserts the longitudinal dividing lines 122. In particular, as in the illustrated example, two ultrashort pulse lasers 16 can also be used for two longitudinal dividing lines 122. For the sake of simplicity, the beam-shaping optics 18 of the ultrashort pulse lasers 16 are not shown in the figure. The motion device 24 can also include a beam-deflection optic 241, as in the illustrated example.According to one embodiment, the transverse dividing lines 121 are inserted using a laser beam 20 moved across the glass ribbon 4 by a beam deflection optic 241. The beam deflection optic 241 can, for example, comprise a galvanometer scanner.

[0149] As shown, in a preferred embodiment the aforementioned dividing lines 121 , 122 are first inserted transversely and then longitudinally into the continuous glass ribbon 4.

[0150] The separation of individual glass panes 2, or the so-called full body cut (FBC), by separating or breaking them along the transverse predetermined break lines 121 running perpendicular to the glass ribbon 4, can be carried out by a mechanical separation device 28, for which only particularly low or no separation forces are required after laser filamenting. Edge cutting, i.e., the separation of the edges 13 along the longitudinal predetermined break lines 122 of the glass ribbon 4, can also be carried out by particularly low separation forces, for example, by simple pulling and / or by movement on an acceleration belt 29. An acceleration belt 29, with which the individual glass panes 2 are separated in the direction of movement, can, for example, also be part of a separation device 28, or constitute the separation device 28 itself.

[0151] After the glass panes 2 have been separated and separated, they can be transported to an inspection unit 39 using the transport device 24. The inspection unit 39 can be used to check, among other things, the dimensions of the glass panes and their edge quality.

[0152] It is of course also possible and encompassed by the invention to first insert the aforementioned dividing lines 121, 122 longitudinally and then transversely, i.e. to precede the border cut.

[0153] In particular, achieving good edge quality does not require thermal cutting of the glass ribbon 4 by stress input, nor the induction of thermal stresses by introducing temperature, for example by a CO2 laser, i.e. no so-called thermal cleaving process, for cutting, and no thermal shock cutting, for example by an abrupt temperature reduction, such as by a cold shock.

[0154] The separation can be achieved, for example, by applying mechanical stress with convex rollers or by guiding the separation lines over convex rollers. The edges 13 separated from the remaining glass ribbon 4 can then be collected, for example, in a shard container, possibly located away from the glass ribbon (in a shard cellar / another room). The selected distance allows the glass ribbon to be separated along the separation line 12, 121, 122 by the action of gravity. For this purpose, an overhang of the section of the glass ribbon to be separated can be provided, for example, by a guide device such as a rail or a roller. In an advantageous method, the ultrathin glass ribbon 4 is cooled at a cooling rate that is selected depending on the predetermined glass thickness d, whereby the cooling rate is increased with a predetermined smaller glass thickness d and decreased with a predetermined larger glass thickness.

[0155] Alkali-free aluminum borosilicate thin glass is advantageously suited for use as ultra-thin glass. A class of alkali-free glasses well-suited for this process contains the following components in wt.%:

[0156] SiO2 58 to 65

[0157] B2O3 6 to 10.5

[0158] AI2O3 14 to 25

[0159] MgO 0 to 3

[0160] CaO 0 to 9

[0161] BaO 3 to 8

[0162] ZnO 0 to 2, in particular the sum of the content of MgO, CaO and BaO is characterized by being in the range of 8 to 18 wt.%.

[0163] The glass underlying one embodiment has the following composition in wt.%:

[0164] SiO261

[0165] AI2O3 18

[0166] B2O3 10

[0167] CaO 5

[0168] BaO 3

[0169] MgO 3

[0170] This example glass exhibits high optical transmission and has a

[0171] density p of 2430 kg / m³ 3 and a surface tension y of 0.3 N / m, a thermal conductivity A of 2 W / mK and a specific heat capacity c P of 1360 J / kgK. The transformation temperature T g The operating temperature of AF32 glass is 713°C. It has a low coefficient of thermal expansion, very close to that of silicon. The down-draw process also allows for the production of exceptionally smooth surfaces with a low roughness of less than 1 nm (RMS). The application temperature range extends up to approximately 600°C.

[0172] Another class of glasses suitable for the procedure described here contains the following components in wt.%:

[0173] SiO250 - 70

[0174] AI2O3 10 - 20

[0175] B2O3 5 - 15,

[0176] CaO 4 - 8

[0177] BaO 0.5 - 5

[0178] SrO 4 - 8.

[0179] In another embodiment, a glass was manufactured with the following components:

[0180] SiO260 wt-%

[0181] B2O3 10 wt.%,

[0182] AI2O3 15 wt.%

[0183] SrO 6 wt.%

[0184] CaO 6 wt.%

[0185] BaO 2 wt.%, and 1 wt.% other components.

[0186] According to a further embodiment, a glass ribbon with a thickness of preferably 32 pm ± 5 pm is drawn. An overflow fusion process is suitable, for example. Another class of glasses that are well suited to the invention, since they can be processed into thin glass ribbons and can be easily cut by the insertion of dividing lines as described here, has the following components in wt.%:

[0187] SiO2 30 to 85

[0188] B2O3 3 to 20

[0189] AI2O3 0 to 15

[0190] Na2O 3 to 15

[0191] K2O 3 to 15

[0192] ZnO O to 12

[0193] TiO20.5 to 10

[0194] CaO O to 0.1.

[0195] One embodiment of this class of glasses has the following composition:

[0196] SiO264.0

[0197] B2O3 8.3

[0198] AI2O3 4.0

[0199] Na2O 6.5

[0200] K2O 7.0

[0201] ZnO 5.5

[0202] TiO24.0

[0203] Sb2O30.6 ci- 0.1

[0204] Glass panes with this composition generally exhibit the following characteristics

[0205] Features on:

[0206] CTE ( 20-300) 7.2'10' 6 / K

[0207] T g 557°C Density 2.5 g / cm³ 3

[0208] Another class of glasses that can be chemically tempered and are particularly suitable for processing using the method described here contain the following components in wt.%:

[0209] SiC>2 50 to 65

[0210] AI2O3 15 to 20

[0211] B2O3 0 to 6

[0212] Ü2O 0 to 6

[0213] Na2O 8 to 15

[0214] K2O 0 to 5

[0215] MgO 0 to 5

[0216] CaO 0 to 7, advantageous 0 to 1

[0217] ZnO 0 to 4, advantageously 0 to 1

[0218] ZrÜ2 0 to 4

[0219] TiÜ2 0 to 1, advantageously essentially TiO2-free

[0220] The glass may also contain, at 0 to 1 wt.%: P2O5, SrO, BaO; as well as fining agents at 0 to 1 wt.%: SnO2, CeÜ2 or AS2O3 or other fining agents.

[0221] According to one embodiment, ultrathin glass sheets with one of the following thicknesses are produced from a glass with a composition from the above range: 20 pm ± 5 pm, 32 pm ± 5 pm, 40 pm ± 5 pm, 50 pm ± 5 pm, 75 pm ± 5 pm, 100 pm ± 10 pm. The glasses of the aforementioned class can be drawn into thin glass ribbons by both a down-draw and an overflow fusion process. These ribbons can then be easily cut into glass sheets by the method described here, through the insertion of predetermined break lines 12, while achieving high strength. If necessary, the desired glass thickness can also be achieved by thinning, chemically or mechanically, if this is not possible or difficult in the drawing process.

[0222] An example from this class of glasses has the following composition in wt.%:

[0223] SiO260.7

[0224] AI2O3 16.9

[0225] Na2O 12.2

[0226] K2O 4.1

[0227] MgO 3.9

[0228] ZrO21 ,5

[0229] SnO20.4

[0230] CeO20,3.

[0231] All the glasses mentioned here can be easily processed into ultra-thin glass ribbons with a thickness in the range of 5 pm to 100 pm using down-draw methods.

[0232] Without limiting itself to the following descriptions, an ultrathin glass ribbon 4 with a predetermined glass thickness d in the range of 5 pm to 100 pm is advantageously cooled according to the inventive method with a cooling rate of equal to or greater than 50 K / s, particularly advantageously of equal to or greater than 100 Kelvin / s, and most particularly advantageously of equal to or greater than 150 Kelvin / s or of equal to or greater than 200 Kelvin / s.

[0233] Thus, without being limited to the example shown or the glass compositions described here, the ultrathin glass ribbon 4 is advantageously cooled at a cooling rate in the range of 150 Kelvin / s ■ 30 pm / d to 300 Kelvin / s ■ 30 pm / d, where d denotes the thickness of the glass ribbon. This allows for the advantageous and particularly efficient production of ultrathin glass sheets and / or ultrathin glass on a roll with high edge strength, even at high cooling rates, taking into account the glass thickness d.

[0234] Fig. 5 schematically shows the mechanism, according to the prior art, by which the separation of glass ribbons is supposed to take place using non-directional ultrashort pulse laser processing. A top view of a glass element 4 is shown.

[0235] The microcracks 55 have a crack length RL. According to the prevailing explanation, the microcracks 55 are caused by the shock wave generated by the plasma explosion in the focal region of the ultrashort laser pulse within the workpiece material. Viewed from above, the microcracks 55 typically extend radially from the filament 14 as the center point into the workpiece material, since the beam profile, and thus the damage 14, has no preferred direction. If microcracks 55 of adjacent filaments merge to form a connected microcrack 56, these connected microcracks 56 can form a continuous crack line or predetermined fracture line along which the glass ribbon and / or glass element 4 can be separated. The damage in this representation can, in particular, be a filament.

[0236] Fig. 6, in contrast, schematically shows a top view of a glass strip 4 that, according to the present invention, has been processed by directed ultrashort pulse laser treatment in the laser's preferred direction LVR. The defects 14 are arranged on the predetermined breaking or separation line 12. They have a preferred damage direction SVR extending in the direction of the separation line 12. SVR corresponds, at least in its direction, to LVR. The individual defects 14 are spaced apart from each other by a distance A. In the present example, the defects 14 are widened in the direction of the preferred damage direction SVR. In general, the defects 14 can have a shape corresponding to the beam profile of the laser beam during directed ultrashort pulse laser treatment.It is assumed that, due to the expansion of the laser beam in the preferred laser direction LVR and thus also the expansion of the damage in the preferred damage direction SVR, the crack length RL of the microcracks 55 surrounding the damage is dependent on the preferred damage direction SVR. In particular, the microcracks 55 are longer in the preferred damage direction SVR than perpendicular to it.

[0237] This has the particular advantage that the damage 14 in the preferred direction of damage SVR can be arranged further apart from each other and / or microcracks in the preferred direction of damage SVR can form connected microcracks 56 and thus create a dividing line 12, but only fewer and / or shorter microcracks 55 propagate into the material of the glass ribbon 4 and thus a lesser weakening of the edge occurs.

[0238] The preceding explanations regarding microcrack length can also be applied analogously to the consideration of microcrack density, i.e., the number of microcracks in the preferred direction within a volume element of the workpiece is higher than those perpendicular to it. A reduced number and / or density of microcracks 55 away from the preferred direction of damage (SVR) generally weakens the edge and thus reduces the edge strength.

[0239] Fig. 7 illustrates another advantageous embodiment of the invention. Similar to Fig. 6, the defects 14 are arranged along a dividing line 12. The defects 14 were created by directed ultrashort pulse laser processing, with the preferred damage direction SVR running in the direction of the dividing line 12. As described previously, at least one initial crack 60 follows the defect. In the illustrated example, there is one initial crack 60 for each defect 14 in the direction of the dividing line 12 and thus in the preferred damage direction SVR, more precisely in the preferred damage direction SVR and in the opposite direction. Initial cracks other than those lying on the dividing line 12 should not be created. The initial cracks 60 have the initial crack length IRL. The initial crack length IRL is determined as described previously and can be adjusted by suitable laser parameters.An initial crack 60 differs from a microcrack 55, 56 in that it is visible under a light microscope. This is assumed to be because a separation of the glass material has already occurred on a macroscopic scale in an initial crack 60. Similarly, microcracks 65 can form around the damage 14 due to the action of the ultrashort pulsed laser beam; however, these are significantly smaller in length, crack density, and / or crack thickness than the initial cracks. As already described, this is primarily an effect of the directed ultrashort pulse laser processing and the presence of the laser's preferred direction LVR (low-voltage reduction) and, consequently, the preferred damage direction SVR (separate-field reduction). A subsequent microcrack advantageously forms between the opposing ends of initial cracks and contributes to the separation of the element.

[0240] Advantageously, as shown in Fig. 7, the spacing A of the filaments 14 and the initial crack length IRL are adjusted such that the initial cracks 60 are at least substantially adjacent to one another. It is also possible for the initial cracks 60 of adjacent filaments to end at a distance from each other. In this case, a fracture clearance zone 61 forms between the ends of the initial cracks 60, as shown in Fig. 8. The embodiment in which the initial cracks 60 of adjacent filaments 14 touch and / or the fracture clearance zone 61 has a short length is particularly advantageous. This allows for the generation of especially high edge strengths.

[0241] Fig. 8 shows a variation and / or alternative embodiment of the directed ultrashort pulse laser processing in the laser preferred direction LVR and consequently also in the damage preferred direction SVR, similar to Fig. 7. The filaments 14 are further apart than in Fig. 7; the distance A is therefore greater, and the initial cracks 60 of adjacent filaments 14 also end at a distance from each other. A wide fracture zone 61 is thus present. Nevertheless, the glass strip 4 and / or the glass sheet 2 can be easily separated along the separation line on which the filaments 14 are arranged. Between the ends of the initial cracks 60, a fracture zone 61 with a fracture length g is formed by the separation process. g can have significant values, which can lie particularly in the range mentioned in the description. This also allows for the generation of particularly good edge strengths.Likewise, it appears to be a particularly efficient manufacturing process to insert fewer filaments 14 than shown in the embodiment of Fig. 7 and to provide a fracture relief area 61 with fracture relief length g, where g can be several pm. In addition to high edge strength, the fracture relief area 61 also exhibits a particularly smooth edge surface. This is attributed to the fact that apparently fewer and / or only very short microcracks extend from the edge of the fracture relief area 61 into the material of the glass strip 4 and / or the manufactured glass sheet 2.

[0242] Fig. 9 shows a photograph of filament-shaped defects 14 with initial cracks 60 in an ultrathin glass element 4, produced by the described laser method. The photograph shows the ultrathin glass element 4 in plan view. In this example, the thickness d of the glass element was 32 pm.

[0243] The defects 14 are arranged in the preferred direction of damage SVR on a designated separation line (not shown). The initial cracks 60 have an initial crack length IRL, and each defect 14 has two initial cracks on opposite sides of the defect 14, specifically on the separation line. The ends of the initial cracks 60 are spaced apart, with the clearance zone 61 located between them. If the illustrated glass element 4 is separated along the separation line, the clearance zone with clearance length g is formed from the web 61.

[0244] The photographic image was measured. The measured values ​​for the spacing A of the defects 14, synonymous with pitch, were 49.45 pm. The total defect length, i.e., the width of the defects plus the length of the initial cracks, thus F + 2 ■ IRL, was determined to be 20.05 pm.

[0245] Fig. 10 shows a photograph of another embodiment, here at a higher magnification, also in a top view. Here too, damage 14 was introduced into an ultrathin glass element 4 by directed ultrashort pulse laser processing in the substrate's preferred direction SVR using the described laser method and measured. A total damage length of F + 2 ■ IRL of 19.47 pm was measured. The thickness d had the same value as in the embodiment shown in Fig. 9.

[0246] The photographs clearly show that the described method can reliably generate directed ultrashort pulse laser treatment in the preferred damage direction SVR in an ultrathin glass element. It is also evident that damage 14 and initial cracks 60 can be reliably generated, extending in the preferred damage direction SVR (and / or in the opposite direction).

[0247] Figure 11 shows the cross-section through ultrathin elements of thickness d made of glass-based material 2, 4, processed as described, to schematically illustrate possible forms of defects 14, here in the form of filament-shaped defects. The figure shows a top view of an edge 30 of an element 2, 4 separated along the dividing line 12, 121, 122. In these examples, the filament-shaped defects 14 are designed as hollow channels. Figure 11a shows the simplest case, where cylindrical hollow channels are introduced into the element 2, 4 as filament-shaped defects 14. The defect or filament axis X passes through the center point of the filament-shaped defects 14, also called filaments. The filament walls are axially symmetric. In the example shown, the filaments 14 connect the top 51 of element 2, 4 with its bottom 52.The hollow-channel filament 14 thus represents a through-channel or a through-opening. As previously described, it is also possible that the filament 14 does not form a hollow channel, but rather is a defect in element 2, 4 and / or terminates as a blind hole in element 2, 4. The diameter of the filament 14, encompassing both the hollow-channel filament and the defect, is denoted by F. F is measured in the preferred direction of damage SVR, as described. The filament-shaped defects 14, measured from the respective filament axis X, are spaced apart by the distance or, synonymously, pitch A.

[0248] In the example shown, initial cracks 60 originate from the damaged areas, here the filaments 14, in the preferred direction of damage SVR. These have an initial crack length IRL. If the initial cracks are not of a constant length along the damage axis X, IRL is measured by projection from one of the surfaces 51, 52, thus determining the maximum initial crack length. This is shown using the right-hand damage in Fig. 11.

[0249] Between the ends of the initial cracks 60 there is a free fracture area 61 which, in the case of a detached element, together with the separated damages 14, forms the fracture edge 30.

[0250] Fig. 12 shows a top view of an ultrathin element made of glass-based material 2, 4, into which defects, here filament-shaped defects 14, are introduced along separation lines 12, 121, 122. In particular, this Fig. shows a section of the glass ribbon 4 as shown in Fig. 1 and / or Fig. 4.

[0251] As previously described, transverse dividing lines 121 and longitudinal dividing lines 122 are present. In particular, the longitudinal dividing line can separate the border 13, which, for the sake of clarity, is only shown on one longitudinal side of element 2, 4, but is usually present on both longitudinal sides in real objects.

[0252] Element 2, 4 is not yet separated in the representation. This can be done in a subsequent step, as described. Element 2, 4 essentially corresponds to a pane of glass whose edges are cut off. It is also possible to extract the inner contour.

[0253] The defects 14 are arranged along the dividing line 12 at a distance A. The defects are widened along the preferred direction of damage SVR. This preferred direction SVR extends in the direction of dividing lines 12, 121, and 122. Since in this example both a longitudinal section along the longitudinal dividing line 122 and a cross section along the transverse dividing line 121 are to be made, two preferred directions of damage SVR are also provided, which run in the direction of the respective dividing lines 121 and / or 122.

[0254] As can also be seen from Fig. 12, it may be provided that the distance A of the filaments 14 on the transverse dividing line 121 is different from that on the longitudinal dividing line 122. Since the direction of the preferred damage direction SVR corresponds, as described, to the direction of the preferred laser direction LVR, the above also applies to LVR.

[0255] Figure 12 also shows that the defects 14 with widening in the preferred direction of damage SVR can be formed with or without a subsequent initial crack 60. In the present example, defects 14 with initial cracks 61 are provided, which lie on both sides of the defects 14 on the dividing line 12, 121, 122. As described, the initial cracks have the initial crack length IRL. As also already described, IRL and the distance A can be selected such that the initial cracks 60 are directly adjacent to each other or that a clearance fracture zone 61 with the clearance fracture length g is present between the ends of the initial cracks 60. It is also evident that g can have a different value and / or length on the transverse dividing line 121 than on the longitudinal dividing line 122. The same applies to the initial crack length IRL.

[0256] It has proven advantageous if the damages on the longitudinal dividing line 122 and on the transverse dividing line 121 are arranged such that a damage 14 is located at the intersection points of these dividing lines, particularly advantageously its center point and / or its damage axis X.

[0257] The described method results in the border 13 being reliably separated from an ultrathin glass ribbon 4.

[0258] Fig. 13a shows a top view of an ultrathin element made of glass-based material 2 in the region of a separation line 12, specifically before it was separated along the separation line 12. The view is, in effect, a magnification of a region of Fig. 12. The defects 14, widened in the preferred direction of damage SVR, have a diameter F, measured at their maximum extent, and two initial cracks 60 each, located on the separation line 12 and on the separation line 12, with initial crack length IRL. The initial cracks are located on both sides of the defect 14 on the separation line 12 and are, in effect, opposite each other. The distance A between the centers of the defects 14 and IRL is chosen such that a clearance fracture zone 61 with clearance fracture length g is located between the initial cracks and on the separation line 12.

[0259] Fig. 13b shows a top view of a similar element to that shown in Fig. 13a, which, however, has been separated along the dividing line 12. An edge 30 is therefore present along the dividing line 12. In this example, the damage 14 is also, so to speak, at least partially broken open.

[0260] In the example shown here, A, F, and IRL are chosen such that the initial cracks overlap. Therefore, no clearance zone 61, as defined in this description, is present. As previously described, the overlap of the initial cracks can be described by the distance-filament relationship Q, where Q = A - (F + 2 ■ IRL). In the example shown in Fig. 13b, Q has a negative value, indicating an overlap of the initial cracks. For positive values ​​of Q, a clearance zone with web width g is present. As also previously described, particularly advantageous values ​​of Q are in the range around 0, i.e., specifically from -1 pm to 10 pm. This applies at least to the top surface 51 of element 2, i.e., the side facing the laser.

[0261] Fig. 13c shows a similar example to Fig. 13b, except that A, F, and IRL are chosen such that Q > 0, thus providing a clearance zone 61 with clearance length g between the respective ends of the initial cracks 60. A clearance length g of approximately 10 pm is therefore particularly advantageous.

[0262] Fig. 14 shows a diagram of the measured edge strength K of an ultrathin element made of glass 2, 4, which was separated along the separation lines 12, 121, 122 using the described method, as a function of the distance A of the defects 14. The distance A is synonymously called pitch.

[0263] In particular, the damage 14 corresponded to that shown in Figs. 9 and 10; the ultrathin glass element 2, 4 had a thickness d of 32 pm. Thickness variations and / or measurement inaccuracies can amount to approximately max. 3 pm to max. 5 pm in all examples shown.

[0264] The curves do not differ in principle for the damage diameters described herein and largely overlap, so a separate presentation has been omitted.

[0265] Figure 14 shows that, quite surprisingly and remarkably, a maximum of edge strength occurs in the pitch range between 15 pm and 50 pm, with two local maxima at approximately 20 pm and 40 pm pitch. The position of these maxima is astonishingly independent of the material thickness or the thickness d of the ultrathin glass-based material.

[0266] In the example underlying Fig. 14, the measurement was terminated at a pitch of 2 pm as the lower limit or minimum distance. The improvement in edge strength in the described pitch range is essentially independent of the diameter F, at least as long as F is less than 10 pm. The improvement in edge strength in the shown range is extremely significant; an increase in edge strength of more than 30% is achieved for the main maximum at a pitch of 20 pm, and a similar increase is achieved for the secondary maximum at approximately 40 pm.

[0267] Fig. 15 shows the relationship between the product R = KY (edge ​​strength) and yield Y as a function of pitch, measured on the same samples as in Fig. 14. As previously described, the yield Y includes a classification into good parts and rejects. As can be seen from the graph, there are still main maxima with significantly improved R-values ​​at the same pitch values ​​A as before; however, the yield Y decreases at the second main maximum with a larger pitch compared to the first main maximum with a smaller pitch.

[0268] It is assumed that the second main maximum corresponds to the presence of a fracture zone 61 along the edge 30. The edge strengths are approximately the same for closely spaced defects 14, especially those with subsequent initial cracks 60, as for a larger pitch A with a clearly defined fracture zone 61. However, the presence of the fracture zone results in more scrap. This can possibly be explained by the fact that the separation mechanism in the presence of the fracture zone 61 is based on the propagation of an induced microcrack. The longer the crack must be propagated in the fracture zone 61 during separation, the higher the required separation force. Statistically, this increases the probability that the crack propagation will occur not only along the separation line 12, 121, 122, but also along a transverse crack that is present in the direction of the material. This can explain the lower yield with increasing pitch.Furthermore, it can be assumed that microcracks perpendicular to the separation direction can be lengthened by higher separation forces in longer fracture zones, even if the specimen does not completely fracture along these cracks. These microcracks, lengthened by the separation process and extending into the material, are presumably responsible for the decreasing edge strength with increasing pitch of 32 m and the resulting larger fracture zones.

[0269] The inventors recognized that the existence of the two maxima allows the pitch to be selected within a relatively wide range to ensure high edge strength. This allows for a high degree of process stability within a specified window, balancing edge strength and processing speed, which increases with increasing pitch A. Ultimately, this helps to reduce scrap and thus improve resource efficiency.

[0270] The stable process windows provided by the invention make it possible to process ultrathin elements made of glass-based material, in particular ultrathin glass, as a glass ribbon 4 and thus continuously, and finally to make them available as glass on a roll.

[0271] For illustration, Fig. 16 shows a photographic cross-section through a region of an ultrathin glass element 2, 4 of thickness d, processed as described. The perspective largely corresponds to that of Fig. 11a. The element thickness was again 32 pm. The cross-section runs along the dividing line; the photograph thus shows a top view of the edge of the separated element 2, 4. The preferred direction of damage (SVR) of the defects 14 also lies on the dividing line. Two defects 14 through which the cross-section passes are visible. Each defect consists of a group of individual defects, here defects 141 and 142, which are formed as hollow channel-shaped elements. These were generated by a split beam profile according to that of Fig. 3(i). Similar structures can be achieved by applying beam profiles according to Fig. 2(c), (e), (g) and Fig. 11a.3 (i) and (j) can be observed. The geometric center of the defects 14 is spaced apart by a distance A. Initial cracks 60, originating from the defects 14 and exhibiting an initial crack length IRL, are also clearly visible. The laser beam was directed from the top surface 51 of the element. Based on the photograph, the defect appears to penetrate the element from the top surface 51 to the bottom surface 52, although the actual interface in some depth regions, particularly near the bottom surface 52 of the element, does not extend through the filament-shaped hollow channels. The position and extent of the defects 14 and / or individual defects are, of course, adjustable within the scope of the invention.

[0272] For the sake of completeness, a corresponding device 1 is shown schematically in Fig. 17. Device 1 largely corresponds to that in Fig. 1. The analogous description applies. However, at least one longitudinal cut is made along the longitudinal dividing line 122 on the glass strip 4, and thus continuously. The border 13 is removed during the longitudinal cut.

[0273] The edges are usually present on both sides of the glass strip 4, so that two longitudinal cuts are usually made along the two longitudinal dividing lines 122 present on the glass strip 4. As described, this is made particularly advantageous by the inventive method with directed filamentation, especially since the glass strip 4 does not break during the edge cutting.

[0274] The glass ribbon is then wound onto the 160 mm reel. For this, the reel is rotated along the direction of rotation U at a rotational speed correlated to the speed of the glass ribbon 4. The ultrathin glass and / or ultrathin glass-based material wound onto the reel can then be supplied as glass on a reel for further processing.

[0275] To remove the roll 160, a cross-section can be made along a transverse separation line 121 at a suitable time. It is also possible to design the cross-section in such a way that the glass strip 4 is not completely separated, but rather that a predetermined separation line and / or predetermined break line 121 is created, along which singulation can later be easily performed, especially when the glass strip 4 is unwound from the roll 4 during further processing. Thus, the invention has the advantage that it provides, for the first time, a processing window for the pitch, i.e., the distance A between adjacent defects 14, for ultrathin elements made of glass-based material 2, 4, within which particularly good edge strengths can be achieved. The invention balances processing speed and manufacturing quality in such a way that a rational manufacturing process for ultrathin elements made of glass-based material 2, 4 with a low reject rate is enabled.In particular, directed ultrashort pulse laser processing enables the processing of ultrathin glass-based material in a continuous process. With its reliably provided high edge strength K, the product can be transported and / or further processed. This allows for a broader application of ultrathin elements made of glass-based material 2, 4, especially ultrathin glass.

[0276] Reference symbol list

[0277] 1 Device for manufacturing

[0278] 2 panes of glass

[0279] 4 Glass band

[0280] 6 slotted nozzles

[0281] 8 Hot forming device

[0282] 10 Glass melt

[0283] 12 dividing line(s)

[0284] 121 transverse dividing line(s)

[0285] 122 longitudinal dividing line(s)

[0286] 13 Border

[0287] 14 damage(s)

[0288] 141 Damage to a damage group

[0289] 142 Damage to a damage group

[0290] 15 Pressure roller

[0291] 16 ultrashort pulse lasers

[0292] 18 beam-shaping optics

[0293] 20 laser beam

[0294] 22 Focus area

[0295] 24 Movement device

[0296] 26 Cooling unit

[0297] 27 Cooling oven

[0298] 28 Separation device

[0299] 29 Acceleration band

[0300] 30 edge(s)

[0301] 32 - 38 beam profiles

[0302] 39 Inspection Unit

[0303] 51 Top

[0304] 52 Underside

[0305] 55 microcracks

[0306] 60 Initial crack(s) 61 Free break area

[0307] 160 roll

[0308] 240 conveyor belt

[0309] 241 Deflection optics d Thickness of the element made of glass-based material

[0310] A distance between filamentous lesions, synonymous with pitch

[0311] L Diameter Laser beam profile in laser preferred direction LVR

[0312] FS diameter laser beam profile perpendicular to the laser

[0313] Preferred direction LVR F Diameter of filamentous damage in preferred direction

[0314] IRL Initial crack length

[0315] Q Distance-filament relationship a Angle of the wall of a defect g Clearance length between defects U Direction of rotation

[0316] LVR laser preferred direction

[0317] SVR damage preference direction

[0318] X Filament axis

Claims

Patent claims 1. Method for producing ultrathin elements from glass-based material (2, 4), in particular from glass and / or glass-ceramic, comprising the following steps: - Providing an ultrathin element made of glass-based material (2, 4) with a material thickness (d) of 5 to 100 pm, - Generating a focused laser beam (20) using at least one ultrashort pulse laser (16) with a laser wavelength in which the element made of glass-based material is at least substantially transparent, - wherein the beam profile of the laser beam (20) is shaped such that it has a laser preferred direction LVR, - where the laser preferred direction LVR means that the extent of the laser beam (20) in the direction of a dividing line (12, 121, 122) is greater than perpendicular to it, and - Introducing damage (14) into the ultrathin element made of glass-based material (2, 4) with the focused laser beam (20) along a separation line (12, 121 , 122), - where adjacent damages (14) are spaced (A) apart from 15 pm to 50 pm, - where the distance (A) between the centers of adjacent damages (14) is measured.

2. Method according to claim 1, wherein the damages (14) consist of a single damage or of a group of damages (141, 141), preferably of a group of 2 to 4 damages (141, 141), in particular of a group of 2 to 3 Damages (141 , 141) or a group of 2 damages (141 , 141 ); preferably the damages (141 , 141) are filament-shaped.

3. Method according to at least one of the preceding claims, wherein the material thickness d is from 5 pm to 50 pm, preferably from 7 pm to 40 pm.

4. Method according to at least one of the preceding claims, wherein the distance A is from 17 pm to 28 pm, in particular from 18 pm to 25 pm or from 33 pm to 45 pm.

5. Method according to at least one of the preceding claims, wherein the damages (14) have a diameter F and a damage preferred direction SVR; preferably F is from 0.2 pm to 5 pm, measured in damage preferred direction SVR.

6. Method according to at least one of the preceding claims, wherein the damage (14) extends from a top side (51) to the opposite bottom side (52) of the element made of glass-based material (2, 4).

7. Method according to at least one of the preceding claims, wherein at least one initial crack (60) in the substrate preferred direction SVR is connected to each damage (14) with an initial crack length IRL, determined as the maximum crack length measured in transmitted light; preferably the initial crack length IRL of the initial cracks (60) in the substrate preferred direction SVR is from 6 pm to 16 pm, in particular from 8 pm to 12 pm or from 9 pm to 11 pm.

8. Method according to at least one of the preceding claims, wherein a distance-damage relationship Q is established, wherein Q is determined by Q = A - (F + 2 ■ IRL), and Q lies in a range from -4 pm to +40 pm, in particular from -1 pm to +30 pm or from -0.2 pm to 30 pm or from 2.0 pm to 10 pm.

9. Method according to at least one of the preceding claims, wherein the glass-based material element (2, 4) is separated along the separation line (12, 121, 122), wherein a clearance fracture area with a clearance fracture length g of 0.1 pm to 40 pm is generated between damages (14) along the separation line (12, 121, 122), or the clearance fracture length g is in the range 0.1 pm < g < F + 2 IRL, preferably in the range 0.1 pm < g < F + IRL, particularly preferably in the range 0.1 < g < (F + IRL) / 2.

10. Method according to at least one of the preceding claims, wherein the glass-based material element (2, 4) is cut off along the separation line (12, 121, 122) forming at least one edge (30), wherein the edge strength K of the element is more than 170 MPa at least on one side of the separation line (12, 121, 122), preferably from 170 to 400 MPa or from 180 to 380 MPa or from 180 to 250 MPa, particularly preferably an edge strength K in the range of 2.5 d < K < 6 d.

11. Method according to at least one of the preceding claims, wherein the glass-based material element (2, 4) is separated along the dividing line (12, 121, 122), wherein the product R of edge strength K of the element (2, 4) and yield Y is greater than 100, preferably greater than 150, and particularly preferably greater than 100 to 400 or greater than 150 to 300, wherein the yield is determined by Y = 1 - (Nbad / Naii) with Nbad representing the number of rejected parts and Naii the total number of elements examined (2, 4).

12. Method according to at least one of the preceding claims, wherein the element made of glass-based material (2 ,4) is in the form of a planar substrate (2, 4), in particular as a glass and / or glass-ceramic disc (2), and wherein the dividing line (12, 122) is preferably inserted into edge regions of the planar substrate (2, 4).

13. Method according to at least one of the preceding claims, - wherein the glass-based material is in the form of a continuous glass ribbon (4) with a predetermined glass thickness d, - wherein at least one longitudinal dividing line (122) is produced at least along the length of the glass strip (4) with an edge having a thickened border (13) and wherein the border (13) is cut off along the longitudinal dividing line (122) forming an edge (30), and / or - wherein at least one transverse dividing line (121 ) is produced transverse to the glass strip (4) and wherein glass panes (2) are cut off at the transverse dividing line (122) running transverse to the glass strip (4) forming edges (30).

14. Method according to claim 13, wherein the at least one longitudinal dividing line (122) is inserted in the hot area of ​​the glass ribbon (4).

15. Method according to at least one of the preceding claims, wherein the beam profile of the laser beam (20), in particular the extent of the laser beam (20) and / or the damage (14) in the direction of the separation line (12, 121, 122), is reduced by a factor in the range of 1, 3 to 5, in particular is larger by a factor in the range of 1.5 to 4 than the extension in the direction perpendicular to the dividing line.

16. Method according to at least one of the preceding claims, wherein the separation of the borders (13) at the longitudinal dividing lines (122) and / or the separation of glass sheets (2) by separation at the transverse dividing lines (121) running transversely to the glass ribbon (4) is carried out mechanically.

17. Method according to at least one of the preceding claims, wherein after the borders (13) have been cut off, the glass ribbon is wound onto a roll (160).

18. Ultrathin element made of glass-based material (2, 4) with a thickness (d) in the range of 5 pm to 100 pm, which has defects (14) along at least one edge having a spacing A of 17 pm to 28 pm, in particular of 18 pm to 25 pm or of 33 pm to 45 pm; preferably the ultrathin element made of glass-based material (2, 4) is in the form of a glass ribbon, glass sheet or glass roll (160).

19. Ultrathin element made of glass-based material (2, 4) according to claim 18, wherein the defects (14) consist of a single defect or of a group of defects, preferably of a group of 2 to 4 defects (141, 142), in particular of a group of 2 to 3 defects or a group of 2 defects; the defects (141, 142) are particularly preferably filament-shaped.

20. Ultra-thin element made of glass-based material (2, 4) according to claim 18 and / or 19, wherein an initial crack (60) is associated with the damage (14) along the edge with an initial crack length IRL; preferably The initial crack length IRL is from 6 pm to 16 pm, in particular from 8 pm to 12 pm or from 9 pm to 11 pm.

21. Ultrathin element made of glass-based material (2, 4) according to at least one of claims 18 to 20, with a distance-damage relationship Q, wherein Q is determined by Q = A - (F + 2 ■ IRL), and Q lies in a range from -4 pm to +40 pm, in particular from -1 pm to +30 pm or from -0.2 pm to 30 pm or from 2.0 pm to 10 pm.

22. Ultra-thin element made of glass-based material (2, 4) according to at least one of claims 18 to 21, wherein a fracture-free area (61) with a web width g of 0.1 pm to 40 pm is located between damages; preferably the web width g is in the range 0.1 pm < g < F + 2 IRL, particularly preferably in the range 0.1 pm < g < F + IRL, most preferably in the range 0.1 < g < (F + IRL) / 2.

23. Ultra-thin element made of glass-based material (2, 4) according to at least one of claims 18 to 22, wherein an edge with damage (14) has an edge strength K of more than 170 MPa, preferably from 170 to 400 MPa or from 180 to 380 MPa or from 180 to 250 MPa, particularly preferably an edge strength (K) in the range of 2.5 d < K < 6 d 24. Device for carrying out a method according to at least one of claims 1 to 17 and / or device for producing an ultra-thin glass element according to at least one of claims 18 to 23.

25. Use of an ultrathin element made of glass-based material (2, 4) according to at least one of claims 18 to 23 or of an ultrathin Elements made of glass-based material (2, 4) can be produced according to at least one of claims 1 to 17 for insulating intermediate substrates or spacers for electronic components, for encapsulating optoelectronic components, as carriers for thin-film cells, such as thin-film batteries or thin-film solar cells, as cover elements for displays, in particular hinged and / or foldable displays, or as substrates or composite substrates for displays or for microfluidic cells.

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