Method and apparatus for manufacturing flat glass

Abstract

In particular, the present invention provides a method for manufacturing glass ribbons having a glass thickness of 0.1 to 1.3 mm in the usable area, which avoids or at least reduces the generation of mechanical stress between the edges and the thinner usable area, especially during the cooling process. [Solution] The temperature of the glass is 10 10 Viscosity of dPas ~10 15 At a stage in the manufacturing process where the viscosity is within the range of dPas, lasers 9 and 10 are used to collide laser beams 90 and 91 into the region between the usable region 3 and the edge region 5 of the glass ribbon, causing the glass to melt and / or ablate through a photothermal process. Then, the relative movement between the glass ribbon 1 and the laser beams 90 and 91 causes the usable region 3 and the edge region 5 to separate from each other.

Description

Technical Field

[0001] The present invention generally relates to the manufacture of sheet glass or articles made of sheet glass and to corresponding glass articles. In particular, the present invention relates to a method and an apparatus for processing the edges of a continuously and endlessly manufactured glass ribbon.

[0002] Background of the Invention From the prior art, various methods for manufacturing glass ribbons are known. In particular, as an option for manufacturing thin glass, manufacturing glass by the drawing method can be mentioned. In this case, a glass melt is supplied and thinned out by a subsequent drawing process. In this case, the glass melt can be supplied by various methods.

[0003] For example, in the float process, the glass melt is distributed on a liquid tin bath and withdrawn to form a ribbon. A characteristic feature of a glass ribbon produced by the float process is the thickened edge of the ribbon, also called the "ear". The ears are mainly caused by the soft glass at the edge of the ribbon contracting due to surface tension.

[0004] Further options for manufacturing glass ribbons by the drawing method are drawing methods such as the down-draw method or the up-draw method. Here, the glass melt is supplied into a drawing tank having a nozzle. Also in these methods, ears may appear at the edges of the glass ribbon.

[0005] During the cooling process of the glass ribbon in the manufacturing process, the edges become transiently longer than the ribbon in the region between the edges. This creates temporary stress based on the thickness difference between the edge region (edges) and the net region between the edges. This temporary stress can load the glass ribbon and potentially increase the risk of fracture. Additionally, if the glass in the thicker edges passes through the glass transformation temperature range later than the thinner glass in the net region during cooling, permanent stress may develop. This permanent stress increases with further cooling, similarly increasing the risk of fracture. In the case of thin glass ribbons, the percentage difference in thickness between the thickened edge region and the thinner usable region is greater than in the case of thicker glass ribbons, making the temperature difference between the edge region and the usable region particularly pronounced. Correspondingly, the mechanical stress in the glass ribbon increases as the glass thickness decreases. Therefore, the manufacturing of thin glass ribbons, especially those with a thickness of less than 1.3 mm, is particularly susceptible to stress-induced fracture.

[0006] Not only the glass thickness, but also the glass properties can affect stress generation. Therefore, the thermal expansion coefficient α, especially when it exceeds the glass transformation temperature, is important. liq And the coefficient of thermal expansion α in the temperature range of 20-300°C 20-300 Cooling glass with a relatively large difference between its temperature and temperature can result in relatively high stress levels in the glass.

[0007] The stresses described above can, in principle, be minimized by a relatively slow cooling process. However, this is either impossible or extremely difficult to achieve, especially if the glass is rapidly crystallizable. In this case, slow cooling of the glass ribbon may lead to devitrification. Therefore, such glass needs to be cooled as quickly as possible. However, if the cooling process becomes correspondingly faster, the temperature changes during the cooling process will proceed at different rates in regions of different glass thicknesses, which can cause various glass regions to be loaded with different strengths due to temporary stresses. This effect leads to an increased risk of fracture and, therefore, can increase scrap in the manufacturing process. Furthermore, in the case of rapidly crystallizable glass, slower cooling in the edge region may result in this region having a higher degree of crystallinity than other glass regions. Therefore, individual glass regions may also differ in their coefficients of linear thermal expansion, which may result in further mechanical stress being generated in the glass ribbon during the processing, or further increase in mechanical stress in the glass. Therefore, flat glass with corresponding glass properties is not usually produced by the stretching process, or glass produced in this way has a relatively thick glass thickness. In contrast, thin glass ribbons made of glass with a high crystallization tendency or devitrification tendency are not usually produced by the stretching process, or are not produced solely by the stretching process, but are provided, for example, by the rolling process. Unlike the production of glass ribbons by the stretching process, the maximum width and minimum thickness of glass ribbons produced by the rolling process are limited.

[0008] To reduce or avoid stress arising from temperature control (including rapid cooling steps), it is effective to separate the thick edge region (ear portion) from the usable area of ​​the thin net ribbon or glass ribbon at an early stage. This prevents overloading of the glass material by stress generated during the cooling process, thus preventing the possibility of glass fracture. Furthermore, by physically separating the glass regions to be cooled differently, it should be possible to cool the glass ribbon more rapidly according to material-specific requirements without generating high transient stress.

[0009] From International Publication No. 2015 / 172957, a method and apparatus for producing thin glass ribbons having a maximum thickness of 300 μm with separated edges is known. In this case, the thin glass ribbon is drawn from a glass molten material or preform, the edges are separated from the thin glass ribbon by a separation device, and the resulting glass ribbon is cooled. In this case, the separation occurs at a point along the direction of movement of the thin glass ribbon, or during the cooling of the thin glass ribbon when the viscosity of the glass reaches 10 7 dPas~10 11 This is performed at a certain point in the dPas range, which rounds the edges of the newly formed thin glass ribbon created by the separation of the ear portions. However, this method is limited to extremely thin glass. Therefore, in most cases, only glass with a thickness of less than 0.3 mm can be separated by the method described in International Publication 2015 / 172957. The manufacture of thin glass ribbons made of readily crystallizable glass is not disclosed in International Publication 2015 / 172957. Furthermore, this is limited to the downdraw method in International Publication 2015 / 172957.

[0010] Problems of the invention The fundamental problem of the present invention is to avoid or at least reduce the generation of mechanical stress between the edges and the thinner usable area during the manufacturing process, particularly during the cooling process, when manufacturing glass ribbons, especially when manufacturing glass ribbons with a glass thickness of 0.1 to 1.3 mm in the usable area. Furthermore, the invention relates to easily crystallizable glass and / or a glass with a coefficient of thermal expansion α liq and α 20-300 It is desirable to provide a method for producing thin glass ribbons by stretching from glass with a relatively large temperature difference. A further challenge is to provide glass articles made of glass that can be easily crystallized. This challenge is addressed by the subject of the independent claims. Advantageous embodiments of the present invention are defined in each dependent claim.

[0011] Summary of the Invention The present invention relates to a method for manufacturing glass ribbons. In this method, a glass ribbon is first prepared. In this case, the glass ribbon is obtained by a stretching process. The molten glass can be supplied to the stretching process by various methods. According to a first variant, the glass ribbon is formed by stretching or lifting the molten glass on a float bath using floats. In a second variant, it is assumed that the molten glass is supplied to a stretching tank having a nozzle and the glass ribbon is stretched from the nozzle. This can be done, for example, by a down-draw or up-draw method.

[0012] A glass ribbon has a usable region with a nearly uniform thickness and a thickened edge region. In this case, the edge region has a greater thickness than the glass within the usable region and is also called the lug region or lug portion. The lug portion or edge region extends along the edge of the glass ribbon in the stretching direction. The stretching direction is the direction in which the glass ribbon is stretched or transported.

[0013] The glass ribbon, once removed from the molten material, can be deflected up to once. Deflection is not necessary as long as the glass ribbon is supplied by the float process. Preferably, in this embodiment, the glass ribbon is transported horizontally throughout all method steps.

[0014] The glass ribbon is further cooled during transport. Preferably, the glass ribbon is passed through a cooling furnace. In this method step, transport is preferably carried out horizontally, i.e., perpendicular to gravity. In particular, no further deflection of the glass ribbon is performed. This is particularly advantageous when the glass is supplied by the float method. In one embodiment, it is assumed that the glass ribbon is lifted from the float bath and no deflection of the glass ribbon is performed.

[0015] The extracted or lifted glass ribbon preferably has a thickness of at least 0.1 mm, preferably at least 0.3 mm, particularly preferably at least 0.32 mm, and particularly preferably at least 0.33 mm in the usable area. According to one embodiment, the glass ribbon has a thickness of at least 0.35 mm, more than 0.35 mm, or even at least 0.4 mm in the usable area. In one embodiment, the usable area of ​​the glass ribbon has a thickness of up to 1.3 mm or even at most 0.8 mm.

[0016] In a first variant of the present invention, it is assumed that the glass ribbon is lifted from the float bath, i.e., that it is a floating glass ribbon. According to one embodiment, the glass ribbon is lifted from the float bath or stretched and has a thickness of at least 0.1 mm or at least 0.15 mm in the usable area. Preferably, the glass ribbon has a thickness in the range of 0.1 to 1.3 mm in the usable area.

[0017] According to a second variant of this method, the glass ribbon is drawn from a drawing tank having a nozzle, preferably by the down-draw method or the up-draw method. The glass ribbon provided by this variant is drawn glass. In this variant, a glass ribbon having a thickness of more than 0.3 mm is obtained. Preferably, the glass has a glass thickness of at least 0.32 mm, particularly preferably at least 0.33 mm. According to one embodiment, the thickness is at least 0.35 mm, or even more than 0.35 mm, preferably at least 0.4 mm in the utilization area. Preferably, the glass ribbon has a thickness of at most 1.3 mm, preferably at most 1.1 mm, particularly preferably at most 1 mm, preferably at least 0.33 mm in the utilization area.

[0018] During the cooling of the glass ribbon, at least one laser is used and the laser beam is directed at the glass ribbon. In this case, the irradiation of the laser is carried out at a point in the manufacturing process where the temperature of the glass is in the range of 10 10 dPas viscosity ~ 10 15 dPas viscosity, preferably 10 12 dPas viscosity ~ 10 13 dPas viscosity. With respect to the cooling path or device, the impact point occurs on the glass at a position within the range between the upper cooling point in the case of a viscosity of 10 10 dPas and the lower cooling point in the case of a viscosity of 10 15 dPas.

[0019] The laser beam strikes the glass ribbon perpendicular to the glass surface, and the point of impact of the laser beam, or multiple points of impact, are positioned in the region between the usable region and the edge region of the glass ribbon. Thus, the relative movement between the glass ribbon and the laser beam, particularly the further transport of the glass ribbon in the stretching direction, causes the laser beam to etch a line in the stretching direction of the moving glass ribbon. This line forms a separation line that spatially separates the usable region and the edge region of the glass ribbon from each other. According to one embodiment, the glass ribbon is moved horizontally while the laser beam is etching the glass. This is particularly advantageous in the case of glass provided by a float process. In other embodiments, it is assumed that the glass ribbon is transported vertically during laser irradiation.

[0020] The wavelength of the laser is preferably selected such that the laser has a low penetration depth into the glass of the glass ribbon. Preferably, the wavelength is selected so that the glass ribbon is directly heated by the beam only in a near-surface region, particularly to a depth of up to 1 / 3 of the glass thickness in the usable area measured from the glass surface. According to one embodiment, the glass ribbon is heated to a depth of 0.1 mm measured from the glass surface. According to one embodiment, the laser beam is generated by a CO2 laser.

[0021] At the point of laser impact, the glass is locally photothermally treated. This photothermal process locally heats the glass intensely in that region, which can cause a decrease in viscosity and / or ablation of the glass within the region of impact. In the sense of this disclosure, the term “photothermal process” is understood to mean a process that includes the melting and / or laser ablation of glass. In this case, the melting and laser ablation may occur with varying intensities depending on the respective method parameters. According to this disclosure, both processes that melt a material without ablation and processes in which laser ablation is primarily performed are subject to the term “photothermal process.”

[0022] According to one embodiment, the photothermal process during laser irradiation significantly reduces the viscosity of the glass within the collision point region. The glass melts in this region across the entire thickness of the glass within the collision point region, thereby forming a gap or aggregate of gaps along the separation line, and separating the usable region of the glass along this line at least partially from the thickened edge region. Thus, the usable region and the thickened edge region are mechanically separated from each other. A new edge is formed along this line.

[0023] The glass ribbon processed in this way, that is, the glass ribbon consisting of the usable region of the glass ribbon, is further cooled after the separation process.

[0024] In the method according to the present invention, the glass reaches a transformation point T at the time of laser irradiation. g It has a temperature close to [a certain value]. In the temperature range according to the present invention between the second cooling point and the transformation point, the glass ribbon has a viscosity that suppresses the formation of mechanical stress.

[0025] Preferably, laser irradiation is performed inside a cooling furnace, particularly in the high-temperature region of the cooling furnace. According to one embodiment, the temperature inside the cooling furnace is at least 580°C during laser irradiation. This imposes high requirements on process control and adjustability. Therefore, it is necessary to ensure that the optical structure of the laser is configured to be extremely thermally stable and that individual components are not exposed to temperatures above their decomposition temperatures. Accordingly, according to one embodiment, the laser is flushed with an inert gas or a flushing gas and / or individual components such as deflection mirrors are actively cooled.

[0026] Within this temperature range of the glass ribbon, it is possible to locally heat the glass within the region of the laser impact point to such an extent that a gap is formed and the local viscosity is reduced. In this case, the gap extends across the entire thickness of the glass and is also called a Durchstich (cut-out). The formation of the gap or cut-out can be achieved by both melting and partial ablation processes of the glass. In this method, the glass is not melted or removed only in the region near the surface. In this case, the volume of the region where the gap is formed is determined from the focal size of the impacting laser beam (hereinafter also called the laser spot diameter) and the thickness of the glass. Thus, the glass is cut-out within the region of the laser beam impact point.

[0027] The cutting process, particularly for low viscosity materials, can be achieved by utilizing the surface tension of the low-viscosity material. Surprisingly, after the cutting is formed, no further mechanical influence on the glass ribbon is required for gap formation. Due to the surface tension of the glass, the glass contracts on both sides of the gap, forming new edges on both sides of the gap. In this case, the receding material also forms new ears on the newly formed edges in the usable area. However, due to the relatively small volume of molten glass, these new ears are small and therefore behave similarly to the glass in the usable area of ​​the glass ribbon during subsequent thermal processes. Unlike separation processes in which the glass is fractured, the method according to the present invention creates high-strength edges by melt rounding, thereby imparting high mechanical stability and strength to the glass ribbon during subsequent transport and handling processes. In particular, the edges have a fire-polished portion.

[0028] In this case, the newly formed edge, despite being rounded by melting, exhibits only a slight increase in molten edge thickness. This is achieved by keeping the molten material volume small.

[0029] Preferably, edge formation occurs across the entire irradiated area. However, individualized resealing zones (Wiederverschluesse) may also be formed at the edges.

[0030] Preferably, by the method described above, both the thickened edge region or the ear region of the glass ribbon are separated. Accordingly, the glass ribbon has two collision points of the two laser beams, and two new edges are formed in the usable region of the glass ribbon. Thus, the glass ribbon thus formed preferably no longer has an ear region, and the usable region of the glass ribbon is limited by both newly formed edges. Thus, the newly formed edges form the lateral edges of the glass ribbon, and the lateral edges extend parallel to or at least substantially parallel to the transport direction of the glass ribbon.

[0031] According to one embodiment, the glass ribbon that can be manufactured by the described method has a rounded profile on the newly formed edge or a plurality of newly formed edges.

[0032] In embodiments where the glass ribbon is transported horizontally and a laser beam is shone perpendicularly to it, gap formation occurs parallel to gravity. As a result, the molten glass is also stretched out of the gap region by gravity. Therefore, corresponding embodiments are suitable for the manufacture of relatively thick glass ribbons in particular, without requiring an additional mechanical separation step. Thus, it is possible to manufacture glass ribbons having a glass thickness of at least 0.1 mm, and especially greater than 0.3 mm, up to 1.3 mm, in the usable region. In one embodiment, the glass thickness in the usable region of the glass ribbon is in the range of greater than 0.3 mm to 1.3 mm, preferably in the range of 0.32 to 1.1 mm. Thus, it is also possible to manufacture glass ribbons having a thickness of 0.35 to 1 mm in the usable region, which can be used, for example, as a cover glass.

[0033] Preferably, the apparatus is configured such that the focal diameter or laser spot diameter on the glass ribbon level is adjusted to the glass dimensions and viscosity behavior of each glass by changing the focal position via an adaptive mirror optical system. The gap width can be adjusted by the focal size of the laser beam. In this case, the focal size or laser spot diameter is selected such that the gap width is sufficiently large so that re-contact of the glass at the edge region and subsequent re-sealing of the gap are avoided or at least reduced due to the retraction of the glass based on the surface tension of the glass and, optionally, the effect of gravity on the molten glass. At the same time, the focal size, gap width, and consequently the molten volume are also limited. This prevents the excessive accumulation of molten liquid glass volume and the re-formation of raised edges.

[0034] Surprisingly, the use of a laser beam with a small focal size proved particularly advantageous. This allows for keeping the gap width and, consequently, the molten volume as small as possible, thereby suppressing edge thickening. A laser spot diameter of less than 4 mm, less than 2.5 mm, and particularly preferably less than 1.5 mm was found to be particularly advantageous. According to one embodiment, the laser spot has a diameter of less than 1 mm or even less than 0.8 mm. In advantageous embodiments, spatial and consequently synchronized temporal adjustment of the laser output is performed.

[0035] The irradiated laser power is preferably at least 750 W or even at least 900 W. Surprisingly, combined with a small focal size, these relatively moderate laser powers already achieve a sufficiently high power density, thereby enabling the cutting of even relatively thick glass. At the same time, the heat-affected zone and thus the volume of molten glass are kept small, thereby reducing the edge thickness of the newly formed edge. In one advanced form, adjustment of both the lateral and axial directions of the laser focal point is envisioned. This is particularly advantageous for glass ribbons with relatively large glass thickness in the area of ​​use, as this adjustment allows the cut to be kept open across the entire width of the material while simultaneously keeping the total energy input as low as possible. In advantageous embodiments, spatial and consequently synchronized temporal adjustment of the laser power is performed.

[0036] In the separation method, heat conduction into the heat-affected zone behind the open gap can cause viscous flow of the glass at the already formed separation edge. In this case, the glass is locally compressed based on surface tension, and thus bridging can occur at the gap. This results in a pearl-like arrangement of the resealed gap, accompanied by high material thickness. In this case, if the ratio of the gap length to the length of the resealed region (also called the glass plug) is too small, the connecting material between the newly formed edges within the resealed region will create locally increased stress, thereby resulting in corresponding glass ribbon scrap. However, surprisingly, the inventors have found that by vibrating the laser beam transversely and / or longitudinally in the glass ribbon feeding direction, uniform solidification of the molten glass can be assisted, and thus the above-mentioned bridging by the resealed portion can be reduced. The separation of the ear portion is not prevented by the locally limited and individualized resealed portion of the edge. Therefore, edges that have only individualized, and especially statistically distributed, resealing portions are also included in the term "isolated edges."

[0037] A relative movement of the glass ribbon in the stretching direction is performed between the laser impact point and the glass ribbon. In one embodiment, the laser impact point is fixed, and the relative movement is assumed to correspond to the stretching movement of the glass ribbon. Preferably, the feed rate is at least 1.5 m / min, preferably at least 2.5 m / min, and particularly preferably at least 4 m / min. A correspondingly high feed rate is accompanied by a short action period of the glass at the laser impact point. Thus, the high feed rates mentioned above reduce heat conduction to adjacent glass regions, and therefore keep the heat-affected zone small. This also works to the advantage of molten thickness. Thus, it is possible to further avoid the appearance of thickened molten glass connections between gaps. On the other hand, in order to ensure complete cutting at the separation line by the necessary heat conduction, the feed rate needs to be sufficiently low. Therefore, according to one embodiment, the feed rate is a maximum of 16 m / min, preferably a maximum of 10 m / min, or even a maximum of 8 m / min. In one embodiment, the feed rate is assumed to be a maximum of 6 m / min, preferably 5.5 m / min. Alternatively or additionally, the feed rate is at least 1.5 m / min, preferably at least 4 m / min, and particularly preferably at least 4.5 m / min. According to one embodiment, the feed rate at laser impact is in the range of 1.5 to 6 m / min, preferably in the range of 4 to 5.5 m / min.

[0038] In one embodiment, the irradiated laser power is limited so that the ablation rate in the photothermal process is significantly reduced, and the separation of the glass occurs mainly by a decrease in glass viscosity. The corresponding process is sometimes called soft separation (Weichtrennen). It has been found that it is advantageous to select a laser power limit of less than 2 kW or even a maximum of 1.5 kW. This has been found to be particularly advantageous for glass with a thickness of up to 0.6 mm and / or for glass ribbon transport speeds of up to 5 m / min.

[0039] The inventors found that in the separation process, if the laser spot diameter, feed rate, laser power, and glass thickness are optimally adjusted relative to each other, complete separation can be achieved even with glass ribbons having greater glass thickness, with almost no formation of thickened edges. Therefore, in one advanced form, the ratio of laser power, laser spot diameter, and feed rate is adjusted as follows: Laser output / (Laser spot diameter × Glass thickness × Feed rate) > 6 * 10 8 W * s / m 3 It is assumed that this applies. In this case, 1 * 10 9 W * s / m 3 More than or even 4 * 10 9 W * s / m 3 It was found that the ratio of the super was particularly advantageous. According to one embodiment, this ratio is 6 * 10 9 ~30 * 10 9 W * s / m 3 It is within the range.

[0040] According to one embodiment, the laser intensity profile may be Gaussian, a similar constant distribution, or a top-hat type. In particular, it has been found that using a laser with a top-hat type intensity profile is advantageous when separating glass ribbons with a usable thickness in the mm range or at least 1 mm thick. Therefore, a high peak power of the laser source used is required for the corresponding glass thickness. Surprisingly, in this case, the glass body is already at the transformation temperature T g It was found that, being close to the temperature at which the thermomechanical stress decreases significantly more rapidly than expected, and thereby less severe than in the case of a typical process at room temperature, the glass material does not exhibit a tendency to break edges (e.g., conchoidal fractures) or fracture due to the locally stresses that are temporarily introduced.

[0041] In this case, with a laser having a Gaussian intensity distribution, the glass region at the edge of the beam profile is irradiated with an intensity that reduces the viscosity of the glass only to the extent that it becomes locally and limitedly fluid or that the thermomechanical stress is temporarily reduced, without being sufficient to cut open or contributing to the intended gap formation. Therefore, the heat-affected zone is significantly larger than the gap width, resulting in the localized creation of excessively high melted edges in the usable area of ​​the glass ribbon. In contrast, the top-hat intensity profile has a significantly larger region where the intensity exceeds the burning threshold in the case of laser processing through a steeper slope transition, thus significantly reducing the heat-affected zone compared to the Gaussian intensity distribution. Accordingly, undesirable effects such as excessively high melted edges can be reduced. Furthermore, energy is utilized more efficiently in the top-hat intensity profile.

[0042] In the disclosed method, the above method step of separating the lugs also enables a rapid cooling rate of the glass ribbon without causing excessive stress and glass breakage in the glass. According to one embodiment, the glass ribbon is cooled after the separation of the lugs at a cooling rate of more than 100 K / min, preferably more than 200 K / min, or even more than 300 K / min. By using the early separation of the lugs according to the present invention and the high cooling rate that can be achieved thereby, thin glass ribbons made of glass with a high crystallization tendency can also be produced by the disclosed method.

[0043] Therefore, according to a third variation of this method,

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[0044] In this case, α liq α is a linear thermal expansion coefficient that exceeds the glass transformation temperature of glass. 20-300η is the coefficient of linear thermal expansion of glass at temperatures from 20°C to 300°C. liq This is the liquid-phase viscosity of glass,

number

[0045] Glass that satisfies the conditions mentioned above tends to devitrify or crystallize, which necessitates high cooling rates in the stretching method, particularly in the manufacture of thin glass, preferably with a maximum thickness of 1.3 mm in the usable area. According to one embodiment,

number

[0046] According to one developmental stage, glass is a crystallizable glass used to produce glass ceramics, and is also referred to as green glass below. In particular, this glass is the green glass used to produce LAS glass ceramics or AS glass ceramics.

[0047] A further aspect of the present invention relates to a glass ribbon having two opposing surfaces and a uniform glass thickness extending between them, which can be manufactured by the above method. The glass ribbon having a uniform thickness is a thickness d 中間 An intermediate region having a thickness d 縁部 It has at least two edge regions having a uniform thickness, which form the edge of the glass ribbon. 縁部 A border region having a thickness d of the intermediate region 中間It is understood to be a glass ribbon having an intermediate region having a maximum thickness d of the edge region. 縁部,最大 The thickness d of the intermediate region is 中間 It is up to 150% larger than [the specified size]. Therefore, in particular, the glass ribbon does not have a thickened edge region in the form of a glass tab. A glass ribbon with a uniform thickness is sometimes called a tabless glass ribbon. Preferably, the thickness of the glass ribbon is up to 1.3 mm, and particularly preferably up to 0.8 mm.

[0048] According to the first modified form, the glass ribbon having a uniform thickness is float glass, and preferably has an increased tin concentration on one of its two surfaces compared to the composition of bulk glass. In this case, the increase in tin concentration is due to the molten glass floating in a tin bath. Thus, in this embodiment, this is a glass ribbon manufactured by the float process. This glass ribbon having a uniform thickness has a thickness d in the intermediate region of at least 0.1 mm, preferably more than 0.3 mm, and particularly preferably at least 0.33 mm. 中間 Preferably, it has a thickness d. Preferably, in this embodiment, 中間 It is in the range of 0.1 to 1.3 mm, and particularly preferably in the range of 0.1 to 0.8 mm.

[0049] According to the second variant, the glass ribbon having a uniform thickness is a stretched glass ribbon and / or has two fire-polished surfaces. In this embodiment, the glass ribbon having a uniform thickness in the intermediate region has a thickness d greater than 0.3 mm, preferably at least 0.32 mm, particularly preferably at least 0.33 mm, 0.35 mm, or even more preferably at least 0.4 mm. 中間 It is preferable to have. Alternatively or additionally, in this embodiment, the thickness of the intermediate region is a maximum of 1.3 mm, preferably a maximum of 1.1 mm, and particularly preferably a maximum of 1 mm. According to one embodiment, thickness d 中間 The size is in the range of 0.32 mm to 1.3 mm, preferably in the range of 0.33 mm to 1.1 mm, and particularly preferably in the range of 0.4 mm to 1 mm.

[0050] In addition to or instead of the two variations mentioned above, a glass ribbon with uniform thickness is obtained according to the third variation, as follows:

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[0051] In this case, α liq α is a linear thermal expansion coefficient that exceeds the glass transformation temperature of glass. 20-300 η is the coefficient of linear thermal expansion of glass at temperatures from 20°C to 300°C. liq This is the liquid-phase viscosity of glass,

number

[0052] In one evolutionary form, the marginal region has a thickness d 縁部 It has a maximum thickness d in the edge region. 縁部,最大 However, the thickness d of the intermediate region 中間 It is assumed that this is preferably up to 120%, and particularly preferably up to 100%, greater than the above. Therefore, as a result of localization (Auspraegung), the newly formed edge region has less mass and, therefore, less material to cool. A glass ribbon with a uniform thickness is again T gWhen the cooling process is applied to the vicinity, the volume of the new edge piece and the volume of the usable area of ​​the glass ribbon with uniform thickness, i.e., the edge-less glass ribbon, are relatively small, which allows for even more rapid and minimized suppression of permanent material stress. Accordingly, the difference in the cooling process between the two areas is minimized, thereby achieving a significantly higher cooling rate compared to the original glass ribbon with the edge region, without generating stress between individual regions of the glass ribbon.

[0053] In a further embodiment, the present invention relates to plate-type or disc-type glass articles, particularly flat glass. A plate-type or disc-type glass article is understood to be a glass article having two opposing surfaces having transverse extensions in the x and y directions, and an edge surface between them. The extension of the edge surface in the z direction is equal to the glass thickness d ガラス Correspondingly, the lateral dimensions of both the x and y surfaces are greater than the glass thickness. This glass article is particularly suitable for use as cover glass, for example, as cover glass for displays, or for the manufacture of such displays.

[0054] Preferably, the glass article is manufactured or can be manufactured by the above method or from the above glass ribbon. According to one embodiment, the glass of the glass article is stretched glass, in particular stretched float glass. When a stretched glass article is made, both surfaces of the glass article have low roughness because the surface of the formable glass article does not come into contact with the surface of a forming tool, such as a roller. In one embodiment, it is assumed that at least one surface of the glass article has a fire-polished portion. In contrast, for example, in the case of a glass article obtained by a rolling process, there will be at least one surface whose minimum roughness is limited by the roughness of the roller and / or the surface structure, as long as the corresponding surface is polished following the rolling process.

[0055] Regarding the properties of glass in glass articles, the following relationships apply:

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[0056] In this case, α liq α is the coefficient of linear thermal expansion when the temperature exceeds the glass transformation temperature of glass. 20-300 η is the coefficient of linear thermal expansion of glass at temperatures from 20°C to 300°C. liq This is the liquid-phase viscosity of glass,

number

[0057] The glass article has a thickness d in the range of 0.1 to 1.3 mm, preferably in the range of 0.1 to 0.8 mm, and particularly preferably in the range of 0.3 to 0.8 mm. ガラス It has the following characteristics. According to one embodiment, the minimum lateral dimension l in the x and y directions of the glass article 最小(x,y) It is assumed that the thickness is greater than 400 mm. Alternatively or additionally, according to further embodiments, the glass thickness d ガラス and the minimum lateral dimension l in the x and y directions 最小(x,y) Regarding the aspect ratio between, l 最小(x,y) / d ガラス >500, preferably >1000, especially preferably >4000 It is assumed that this applies.

[0058] Preferably, the glass article has a maximum glass thickness deviation Δglass thickness = d ガラス(最大) -d ガラス(最小)It has a thickness of <0.1 mm. Alternatively or additionally, the glass thickness of the glass article may vary by up to 10%.

[0059] In one embodiment, the glass of the glass ribbon or glass article is assumed to be borosilicate glass, particularly borofloat glass with a thickness of at least 0.25 mm or low-loss borosilicate glass with a thickness of at least 0.1 mm. Low-loss borosilicate glass is understood to be borosilicate glass that exhibits extremely low dielectric loss, especially at 10 GHz. Therefore, for the dielectric loss at 10 GHz, tanδ < 0.0023 may apply.

[0060] According to one embodiment, the glass of the glass article or glass ribbon is borosilicate glass and consists of the following components by weight: SiO274~85 B2O38~25 Al2O3 0.5~4 Li2O 0~1 K2O 0.3~2 MgO 0~3 CaO 0-3 It contains.

[0061] According to one embodiment, the glass of a glass article or glass ribbon is oxide-based and comprises the following components in weight %: SiO257-69, preferably 59-69, particularly preferably 61-69, however, the upper limit may preferably be 67. Al2O3 17-25, preferably 17-21, B2O30~7, preferably 0~5, particularly preferably 0~4.5, Li2O 3-5.5, preferably 3.5-5.5 Na2O 0.8-7, preferably 0.8-6, particularly preferably 0.8-5.5 Includes, Preferably, the total content of Al2O3 and SiO2 is at least 75 to a maximum of 92, preferably a maximum of 90, based on the weight percentage.

[0062] According to one embodiment, the glass of a glass article or glass ribbon is oxide-based and contains the following components by weight: SiO257-69, preferably 59-69, particularly preferably 61-69, however, the upper limit may preferably be 67. Al2O3 17-25, preferably 17-21, B2O30~7, preferably 0~5, particularly preferably 0~4.5, Li2O 3-5.5, preferably 3.5-5.5 Na2O 0.8-7, preferably 0.8-6, particularly preferably 0.8-5.5 K2O 0-1, preferably 0-0.8, particularly preferably 0-0.7, MgO 0-2, preferably 0-1.5, particularly preferably 0-1. CaO 0-4.5 SrO 0-2, preferably 0-1.5, particularly preferably 0-1. ZnO 0-3, preferably 0-2, particularly preferably 0-1.5, P2O50~3, preferably 0~2, particularly preferably 0~1.7, ZrO20~3, preferably 0~2, Includes, Furthermore, impurities and / or clarifying agents and / or coloring components may be present in amounts up to 2% by weight.

[0063] According to one embodiment, the glass of a glass article or glass ribbon is oxide-based and comprises the following components in weight %: SiO262-72, preferably 65-70 Al2O37-14, preferably 8-12 B2O3 0.1-8.5, preferably less than 8.5 or 8 or less, preferably 4-7, particularly preferably 5 or more, and most particularly preferably greater than 5.5 Li2O 5-12, preferably 7-10 Na2O 0-2, preferably 0-1, particularly preferably 0.1 or more and / or less than 1, most particularly preferably 0.3 or more and / or less than 0.8 K2O 0-2, preferably 0-1 Includes, However, 0.8 <Li2O / (Li2O+K2O+Na2O)≦1である。

[0064] According to one embodiment, the glass of a glass article or glass ribbon, in particular the ceramicizable glass, is based on an oxide and contains the following components in weight %: SiO255-75, preferably 62-72 Al2O3 18-27, preferably 18-23 Li2O 2.8-5, preferably 3-5 Na2O 0-4, preferably 0-2 K2O 0-4, preferably 0-2 MgO 0-8, preferably 0-4 CaO 0-4, preferably 0-2 SrO 0-4, preferably 0-2 BaO 0-4, preferably 0-2 ZnO 0-6, preferably 0-2 TiO20-4, preferably 0-3 ZrO20~5, preferably 1.2~4 B2O30~2, preferably 0~0.1 SnO20~2, preferably 0.05~1.6 Includes, Preferably, with respect to the total of components TiO2 and ZrO2, 0 < Σ(TiO2 + ZrO2) < 9.5%, preferably 1.2 < Σ(TiO2 + ZrO2) < 9.5% This applies, or preferably, with respect to the components SnO2, ZrO2, and TiO2, 0 ≤ SnO2 / (ZrO2 + TiO2) < 0.8, preferably 0.01 ≤ SnO2 / (ZrO2 + TiO2) < 0.7 This applies.

[0065] According to one embodiment, the glass of a glass article or glass ribbon is for the production of crystallizable glass, in particular lithium aluminum silicate glass ceramic (LAS ceramic), and is oxide-based with the following components in weight %: SiO265~71 Al2O310~15 B2O30~6 Li2O 0~11 Na2O 0.5~13 K2O 0.1~3 MgO 0-7 CaO 0-3 SrO 0~0.5 Includes.

[0066] Furthermore, the present invention relates to an apparatus for manufacturing a glass ribbon having a uniform thickness from a glass ribbon having a usable region and an edge region that is thicker than the usable region. In this case, the edge region is separated. The apparatus comprises an apparatus for providing the glass ribbon, preferably a float tank, a cooling furnace, and a conveying apparatus for conveying the glass ribbon from the apparatus for providing the glass ribbon through the cooling furnace. According to one embodiment, the conveying of the glass ribbon through the conveying apparatus is performed horizontally. In particular, the conveying of float glass is performed horizontally. At least one laser beam is introduced into the cooling furnace. In one embodiment, the laser beam is introduced by an optical system designed as a cantilever arm, which is assumed to protrude from the side into the cooling furnace. After exiting the laser, the laser beam is deflected to be orthogonal by a deflection element, so that the laser beam collides with the glass ribbon perpendicular or perpendicular to the conveying or stretching direction. In an alternative embodiment, the laser beam is fed vertically through the ceiling of the furnace.

[0067] The point of impact of the laser beam on the glass ribbon is adjusted to be located in the boundary region between the utilization region and the ear region. Inside the cooling furnace, the laser is used when the glass temperature is 10 10 Upper cooling point and 10 for viscosity in dPas 15The collision point is positioned within the cooling furnace, within the range between the lower limit cooling point and the viscosity of dPas, so that it collides with the glass ribbon.

[0068] According to one embodiment, the deflection element is an imaging mirror. It has been found that this device is particularly advantageous if it has a cooling device that actively cools the deflection element or the mirror.

[0069] In one advanced configuration, the laser arm is configured to be rotatable or displaceable. Therefore, the laser arm can be removed from the cooling furnace. This allows for good access, such as for laser maintenance outside the high-temperature region of the cooling furnace. Alternatively or additionally, the laser arm may be equipped with a device for flushing with an inert gas.

[0070] Rollers and / or belts proved to be particularly advantageous as conveying devices.

[0071] Detailed description of the invention The present invention will be described in detail below with reference to Figures 1 to 9. [Brief explanation of the drawing]

[0072] [Figure 1] This is a schematic cross-sectional view of an embodiment of a method for providing glass ribbons by a float process. [Figure 2] This is a schematic plan view of a separation method step according to one embodiment. [Figure 3] This is a schematic cross-sectional view of the ear portion separation in the embodiment. [Figure 4] Figure 3 shows a photographic image of the embodiment illustrated in the diagram. [Figure 5] This is a schematic cross-sectional view of the ear portion separation in a further embodiment. [Figure 6] This is a photographic image of a glass plug. [Figure 7] This is a schematic cross-sectional view of a cooling reactor. [Figure 8] This is a schematic diagram of a glass article according to one embodiment. [Figure 9]Figure 8 shows a schematic cross-sectional view of the embodiment.

[0073] Figure 1 shows a schematic diagram of a first modified form of the method according to the present invention according to one embodiment. In this case, the molten glass 17 flows from the tank to the float bath 2. In this embodiment, the float bath 2 is a tin bath in the float tank 7. A glass ribbon 1 is formed on the float bath 2, having a thinner usable area and thickened edge areas (not shown in Figure 1) at both edges. The glass ribbon 1 is lifted from the float bath 2 by the conveying device 80 and conveyed into the cooling furnace 6 in the conveying direction or the stretching direction 8. In this case, the glass ribbon 2 lifted from the float bath 2 is moved horizontally in the conveying direction 80 at a speed v 送り It is transported in this manner. As is clear from Figure 1, the transport of the glass ribbon 1 in this embodiment is carried out horizontally and perpendicular to gravity. In particular, the glass ribbon 1 is transported horizontally throughout the entire method.

[0074] In the embodiment shown in Figure 1, laser beams 90 and 91 collide with the glass ribbon 1, respectively, within the cooling furnace 6. The collision points 11 and 110 are selected on the glass ribbon 1 so as to be located in the boundary region between the utilization region and the thickened edge region or ear region. Because it is a perspective view, only one laser 90 and the corresponding collision point 11 are shown in Figure 1.

[0075] Laser 9, the corresponding laser beam 90, the glass 10 10 Upper cooling point and 10 for viscosity in dPas 15 The laser 9 is positioned to collide with the glass ribbon 1 at a location having a temperature in the range between the lower limit cooling point and the viscosity of dPas. Thus, the laser 9 is positioned within the high-temperature region of the cooling furnace. Depending on the configuration of each apparatus, the glass ribbon 1 at this point 10 10 The upper limit viscosity of dPas and 10 15 The laser 9 can also be positioned in front of the cooling furnace 6, as long as it has a temperature between the lower limit viscosity of dPas and the temperature limit of dPas.

[0076] Therefore, by the method shown in Figure 1, the thickened edge or ear region can be separated at an early stage of the process, thereby allowing the glass ribbon 30 with uniform thickness to continue to cool rapidly, i.e., at a relatively high cooling rate. This makes it possible to manufacture thin floated glass ribbons made of glass with a high crystallinity tendency, which could not be manufactured using the float method until now. In addition, the method according to the present invention can also provide thin glass, in particular glass with a maximum thickness of 1.3 mm, using the float method, and regarding this,

number

[0077] Table 1 shows the coefficient of thermal expansion, viscosity above the glass transformation temperature, slope of the temperature-viscosity curve at the upper cooling point, and the index that can be obtained by equation (1) for three examples. Glasses 1-3 are thin glass with a maximum thickness of 1.3 mm. Glasses 1-3 are ceramicizable glasses for manufacturing LAS glass ceramics. Therefore, these green glasses have high crystallization potential, but should exist as glass during the manufacture of thin glass. Thus, devitrification during the stretching process can be avoided.

[0078] [Table 1]

[0079] Glass 1 is a crystallizable green glass, which can be converted to LAS glass ceramic by a subsequent ceramicization process. Glass 1 preferably has the following composition in weight %: SiO255-75, preferably 62-72 Al2O3 18-27, preferably 18-23 Li2O 2.8-5, preferably 3-5 Na2O 0-4, preferably 0-2 K2O 0-4, preferably 0-2 MgO 0-8, preferably 0-4 CaO 0-4, preferably 0-2 SrO 0-4, preferably 0-2 BaO 0-4, preferably 0-2 ZnO 0-6, preferably 0-2 TiO20-4, preferably 0-3 ZrO20~5, preferably 1.2~4 B2O30~2, preferably 0~0.1 SnO20~2, preferably 0.05~1.6 It has, Preferably, with respect to the total of components TiO2 and ZrO2, 0 < Σ(TiO2 + ZrO2) < 9.5%, preferably 1.2 < Σ(TiO2 + ZrO2) < 9.5% This applies, or preferably, with respect to the components SnO2, ZrO2, and TiO2, 0 ≤ SnO2 / (ZrO2 + TiO2) < 0.8, preferably 0.01 ≤ SnO2 / (ZrO2 + TiO2) < 0.7 This applies.

[0080] Glass 2 is also a green glass used to manufacture LAS glass ceramics.

[0081] The crystallization potential of this green glass, necessary for the manufacture of glass ceramics, is accompanied by a correspondingly high tendency for glass crystallization. Previously, this tendency for crystallization and the associated relatively high devitrification tendency have been obstacles to the manufacture of thin glass 1 and 2 in the float process. However, the method according to the present invention allows for the separation of the thickened edge or lug region, and the rapid cooling enabled thereby can suppress the devitrification process or premature crystallization during the manufacture of the thin glass.

[0082] Similarly, glass 3 is a green glass used to manufacture LAS glass ceramics, and until now, it could only be manufactured with a glass thickness of approximately 4 mm by the float process. Here, with a glass thickness of approximately 4 mm, even without separation of the lugs, the cooling rate required to suppress crystallization is still sufficiently low to avoid introducing excessively high mechanical stress. However, thinner glasses require higher cooling rates, and for glass 3, it has not been possible to manufacture float-thin glass with smaller thicknesses until now. However, with separation of the lugs and the higher cooling rates that can be achieved thereby, crystallization during the stretching process can be prevented even in the case of thin glass of glass 3. Therefore, by the method according to the present invention, even in the case of glass 3, it is possible to obtain float-thin glass with extremely small thicknesses, particularly in the range of 0.1 to 1.3 mm.

[0083] Figure 2 shows a schematic plan view after the glass ribbon 1 has been lifted from the float bath 2 in the manner shown in Figure 1. The glass ribbon 1 has a central usable area 3 and two thickened edge areas or ear areas 5. After the glass ribbon is transported to the cooling furnace 6, the laser beams 90 and 91 of lasers 9 and 10, respectively, collide with the glass ribbon 1 at the boundary area between the usable width 3 and the ear areas 5. At the time of the collision of the laser beams 90 and 91, the glass ribbon 1 has a temperature below the upper cooling limit and above the lower cooling limit of the glass. At the point of collision, the glass ribbon 1 is cut open by the laser beam. The glass ribbon 1 is fed in the transport direction 8 at a speed v 送りAs they move simultaneously, a gap is formed between the usable area 3 and the ear area 5. In this case, new edges are formed in both the usable area 3 and the ear area 5. In this case, a new glass ribbon 30 is obtained with thickened glass ribbons 50, 51 and a new edge area 32. In this case, the edge area 32 is slightly thicker than the middle area of ​​the glass ribbon 30. The glass ribbon 30 with uniform thickness is further sent through the cooling furnace. The glass strips 50, 51 are waste and can be melted down again, for example. There are several options for further processing of the glass strips 50, 51. Thus, according to one embodiment, the glass strips 50, 51 can be continuously transported further through the cooling furnace 6, just like the glass ribbon 30 with uniform thickness. However, the glass ribbons are bonded to each other, and the glass is T g Because it is hard at temperatures below 5°C, there is a risk of breakage when handling the separated glass strips 50, 51, which can affect the entire glass ribbon 1 and the separated area. Therefore, in other embodiments, it is envisioned that the glass strips 50, 51 be shredded into short, easy-to-handle portions immediately after separation from the glass ribbon 30, which has a uniform thickness. In this case, it has been found to be particularly advantageous to separate the individual portions of the glass strips 50, 51 by heat. Thus, this process has only a very slight mechanical effect on the entire glass ribbon 1. On the other hand, the process of thermal separation of the glass strips 50, 51 is advantageous because the glass is at a relatively high temperature, i.e., T g Because it is slightly below that, it can be implemented particularly easily. Accordingly, thermal shock can be easily achieved. Here, in one advanced form, it is assumed that initial defects are introduced into the glass strips 50, 51 before thermal shock. In this case, mechanical cracks in the glass have been found to be particularly advantageous. In this case, based on the high glass temperature, it is necessary to use a thermally stable material, such as a high-temperature resistant metal.

[0084] Figure 3 shows a schematic cross-sectional view illustrating the separation of the thickened edge region 5 from the glass ribbon 1. In this case, the collision point 11 of the laser beam 90 is located in the boundary region between the usable region 3 and the thickened edge region 5. The shaded surface 12 represents the volume of glass melted by the laser beam 90. Here, in the embodiment shown in Figure 3, the glass ribbon has a thickness d of 0.6 mm in the usable region. A CO2 laser is used as the laser source, with an irradiated power of 1000 W and a focal size of 1 mm. 2 Therefore, a relatively high power is irradiated onto a small surface, resulting in a correspondingly high power density. This allows the glass to be cut open, creating a gap 13. Thus, the glass ribbon 1 is separated into a glass ribbon 30 and a glass strip 50 with uniform thickness, forming edges 33, 34. The small focal size and the feed rate of 4.3 m / min that the glass ribbon receives orthogonally to the laser irradiation during the process keep the gap width small. Furthermore, the small focal size and relatively fast feed rate result in a relatively small heat-affected zone. In particular, substantially only the glass region where the gap 13 is formed is melted.

[0085] In the embodiment illustrated in Figure 3, the ratios of laser power, spot size, and feed rate are adjusted so that both glass regions 3 and 5 of the glass ribbon 1 are completely separated from each other by the gap 13. At the same time, the newly formed edges 33, 34 have molten edges that are only slightly raised.

[0086] This is also evident from Figure 4, which shows photographic images of both separated glass ribbons 30 and 50.

[0087] In this embodiment, the ratio of laser output / (laser spot diameter × glass thickness × feed rate) is 23 * 10 9 W * s / m 3 That is the case.

[0088] Figure 5, similar to Figure 3, shows a cross-sectional view of the separation of the thickened edge region 5 from the glass ribbon 1 according to a further embodiment. Here, 7 mm 2 A larger focal size is selected, and accordingly, the molten volume is also greater than 120. The glass ribbon 1 was moved at a feed rate of 35 mm / s perpendicular to the direction of laser irradiation. Similar to the first embodiment, the formation of a gap 130 occurs first, forming a glass ribbon 30 with uniform thickness and a glass strip 50 with edges 330, 340. Here, because the molten volume is larger and the feed rate is slower, solidification does not occur as rapidly as in the embodiment illustrated in Figure 4, so that regions with glass plugs 14 may be formed individually between edges 330, 340. Thus, localized resealing of the gap 130 may occur individually. Since the formation of glass plugs 14 occurs only individually, the separability of the ear portion 50 is not affected or substantially affected. Thus, in the sense of the present disclosure, edges 330, 340 with individualized glass plugs 14 are also called separated edges. Therefore, the individually formed glass plugs during the process spontaneously break due to, for example, vibration or movement of the glass edges 330, 340, thus freeing both glass edges 330, 340, and thus no further process steps are performed.

[0089] Figure 6 shows a photographic image of a cross-section of the example shown in Figure 5. Between the glass edges 330 and 340, glass plugs 14 were formed at the indicated locations within the gap 13. In this case, the cross-section shown in Figure 6 does not represent the edges 330 and 340, but rather the individual locations where the glass plugs 14 were formed. However, in most cases, the edges 330 and 340 are separated from each other by the gap 13.

[0090] FIG. 7 shows a schematic cross-sectional view of a cooling furnace 6 according to an embodiment. In this embodiment, the conveyance of the glass ribbon is performed in a horizontal plane. A glass ribbon 1 having a thickened edge region 5 and a utilization region 3 is horizontally conveyed through the cooling furnace 6 by a conveying device 80. In this case, the conveyance direction is in the plane of the drawing. From the side, through the side openings provided in the cooling furnaces 61, 62, the laser arms 15, 150 of the lasers 9, 10 protrude. The laser arms 15, 150 further include imaging mirrors 16, 160, respectively. In this case, the laser beams 90, 91 emitted by the lasers 9, 10 first exit parallel to the glass ribbon 1 and are respectively deflected downward by the mirrors 16, 160. At the collision points 11, 110, the laser beams 90, 91 collide with the glass orthogonally to the feed direction of the glass ribbon. In this case, the collision points 11, 110 are located in the boundary region between the thickened edge region 5 and the utilization region 3 of the glass ribbon 1. The laser arms 15, 150 can be run or pivoted out of the cooling furnace 6 through the side openings 61, 62 provided in the cooling furnace 6. According to one embodiment, the mirrors 16, 160 are actively cooled. Further, the laser arms 15, 150 may have a device (not shown in FIG. 7) for flushing with a flushing gas, whereby the laser arms 15, 150 are sealed against the atmosphere in the cooling furnace 6.

[0091] FIG. 8 shows a schematic plan view of a glass article according to the present invention according to an example, and FIG. 9 shows a schematic cross-section across this glass article. In this case, the figures shown in FIGS. 8 and 9 are not to scale, particularly with respect to the individual dimensions of the glass article. The glass article has two opposing side surfaces 24, 26 and an edge surface 25 extending over the entire circumference. The side surfaces 24, 26 have lateral dimensions l x , l y in the x and y directions. The lateral dimension of the edge surface 25 in the z direction corresponds to the glass thickness d ガラス . The examples shown in FIGS. 8 and 9 have a minimum lateral dimension l x , l y of the side surfaces 24, 26 in the x and y directions of more than 400 mmand glass thickness d less than 0.8 mm ガラス The glass article in this embodiment is manufactured by the method according to the present invention and is float glass. In this case, the glass was lifted from the tin bath and side 26 was in contact with the tin bath. Therefore, the area near the surface of side 26 has an increased tin concentration compared to bulk glass.

[0092] The glass in glass articles corresponds to glass 3 from Table 1.

[0093] The glass article has a fire-polished portion on its side surface 24. [Explanation of Symbols]

[0094] 1 glass ribbon 2. Float bath 3. Usage area of ​​glass ribbon 1 4 tanks 5. Thickened edge region or ear portion of glass ribbon 1 6 Cooling furnace 7. Float tank 8. Conveying direction or stretching direction 9,10 Lasers 11,110 collision point 12,120 molten volume 13,130 Gap 14,140,141 Glass plug 15,150 laser arms 16,160 Mirrors 17. Molten glass Sides 24, 26, and 27 25 27 edge surfaces 27 Glassware 30 Glass ribbons with uniform thickness 31 30 intermediate region 32 30 border region 33, 34, 330, 340 Fire-polished edges 50, 51 Glass strips 61,62 Side openings provided in the cooling furnace 80 Conveying device 90,91 laser beams

Claims

1. A method for producing a glass ribbon (30) having a uniform glass thickness by obtaining a glass ribbon (1) from a molten material through a stretching process, - The glass ribbon (1) has a usable area (3) and an edge area (5) that extends along the stretching direction (8) to the edge of the glass ribbon (1) and is thicker than the usable area. - The glass ribbon (1) is cooled, - During cooling, at least one laser (9, 10) directs a laser beam (90, 91) onto the glass ribbon (1), thereby causing the laser beam (90, 91) to draw a line in the stretching direction of the glass ribbon (1) which is moved horizontally based on the movement of the glass ribbon (1). - The collision point (11) of the laser beams (90, 91) is selected such that the line (13) forms a hypothetical separation line between the utilization area (3) and the thickened edge area (5). - The collision point is such that the glass temperature is 10 １０ The upper limit viscosity of dPas and 10 １５ The glass is formed at a position within the range between the lower limit viscosity of dPas, - The laser beam (90, 91) photothermally treats the glass ribbon (1) in the irradiated region (12, 120), thereby forming a gap (13, 130) along the line between the usable region (3) and the thickened edge region (5), resulting in a glass ribbon (30) having a uniform glass thickness and a new edge (33) parallel to the stretching direction (8), and a separated thickened edge region (50). After separation, the cooling of the glass ribbon (30) having a uniform thickness is continued. - The usable area of ​​the glass ribbon (1) has a thickness of more than 0.3 mm, or - The usable area of ​​the glass ribbon (1) has a thickness of more than 0.1 mm, the stretching process includes a float process, and the glass ribbon (1) is lifted from the float bath, or - Regarding the glass of the glass ribbon, [Math 1] ＞１ This applies, However, α ｌｉｑ = The linear thermal expansion coefficient is greater than the glass transformation temperature of the glass, α ２０－３００ = The linear thermal expansion coefficient of the glass at temperatures from 20°C to 300°C, where η ｌｉｑ = This is the liquid-phase viscosity of the glass, [Math 2] = Upper limit cooling point or the glass is 10 １３ The slope of the viscosity curve at a temperature where the viscosity η is dPas is T. １３ = The glass is 10 １３ The temperature at which the viscosity η of dPas is present, and the glass ribbon (1) preferably has a maximum thickness of 1.3 mm in the utilization region. method.

2. The following features: - The laser beam (90, 91) has a wavelength that heats the glass of the glass ribbon (1) only in the area near the surface, preferably to a maximum depth of 0.1 mm. - The laser beam (90, 91) is generated by a CO ２ laser - The glass ribbon (1) is transported horizontally during the cooling and / or laser irradiation: The method according to claim 1, characterized by at least one of the following.

3. The aforementioned laser beam (90, 91) is 4 mm ２ Less than 3 mm, preferably 3 mm ２ Less than 1.5 mm, preferably a maximum of 1.5 mm ２ The method according to claim 1 or 2, having a laser spot diameter of the specified value.

4. The method according to any one of claims 1 to 3, wherein relative movement of the glass ribbon (1) in the stretching direction (8) is performed between the glass ribbon (1) and the collision point (11, 110) of the laser, and the relative movement has a feed rate of at least 1.5 m / min, preferably at least 2.5 m / min, particularly preferably at least 4 m / min, and / or a maximum feed rate of 6 m / min, preferably a maximum feed rate of 5.5 m / min.

5. The method according to any one of claims 1 to 4, wherein the laser beam (90, 91) has an output of at least 750 W, preferably at least 900 W.

6. Regarding the ratio of laser power, laser spot diameter, glass thickness, and feed rate, Laser output / (Laser spot diameter × Glass thickness × Feed rate) > 7 ＊ 10 ８ W ＊ s / m ３ Preferably >1 ＊ 10 ９ W ＊ s / m ３ , especially preferably >4 ＊ 10 ９ W ＊ s / m ３ｗ The method according to any one of claims 1 to 5, wherein the above applies.

7. The method according to any one of claims 1 to 6, wherein the glass ribbon (1) is provided by stretching it on a float bath (2) with a float.

8. The method according to any one of claims 1 to 7, wherein the glass ribbon (1) has a thickness of at least 0.32 mm, preferably at least 0.33 mm, particularly preferably at least 0.35 mm, and very particularly at least 0.4 mm in the utilization area (3), and / or has a thickness in the range of 0.33 to 1.3 mm, preferably in the range of 0.35 to 1.1 mm, and particularly preferably in the range of 0.4 to 1 mm.

9. The method according to any one of claims 1 to 8, wherein the method is carried out in a cooling furnace (6).

10. The method according to any one of claims 1 to 9, wherein the newly formed edge (33) is fire polished.

11. A glass ribbon (30) having a uniform thickness that can be manufactured by the method described in any one of claims 1 to 10, wherein the glass ribbon (30) having a uniform thickness has an intermediate region (31) and at least one edge region (32), the edge region (32) forming the edge (33) of the glass ribbon (30) having a uniform thickness has an intermediate region (31) with a thickness d greater than 0.3 mm 中間 The edge region (32) has a thickness d 縁部 It has, d 縁部 However, the thickness d in the intermediate region (31) of the glass ribbon (30) having a uniform thickness 中間 Maximum thickness d is up to 120% larger than 縁部，最大 A glass ribbon (30) having a uniform thickness.

12. The glass ribbon (30) having a uniform thickness according to claim 11, wherein the edge region (32) is rounded, so that the edge (33) has a rounded profile and / or the edge (33) is fire polished.

13. The uniform thickness glass ribbon (30) according to claim 11 or 12, wherein the uniform thickness glass ribbon (30) has a higher tin concentration in the region near the surface of the side surface than the tin concentration of the glass in the bulk material.

14. Regarding the glass of the glass ribbon (30) having the uniform thickness, [Math 3] >1, preferably >1.1, particularly preferably >1.2 This applies, However, α ｌｉｑ = The linear thermal expansion coefficient is greater than the glass transformation temperature of the glass, α ２０－３００ = The linear thermal expansion coefficient of the glass at temperatures from 20°C to 300°C, where η ｌｉｑ = This is the liquid-phase viscosity of the glass, [Math 4] = Upper limit cooling point or the glass is 10 １３ The slope of the viscosity curve at a temperature where the viscosity η is dPas is T. １３ = The glass is 10 １３ This is the temperature at which the viscosity η of dPas is A glass ribbon (30) having a uniform thickness according to any one of claims 11 to 13.

15. In particular, the two opposing sides (24, 26) and the glass thickness d ガラス A glass article (27) in the form of a plate glass having the glass thickness d ガラス However, the maximum thickness is 1.3 mm, preferably 0.8 mm, and the glass of the glass article is as follows: [Math 5] >1, preferably >1.1, particularly preferably >1.2 This applies, However, α ｌｉｑ = The linear thermal expansion coefficient is greater than the glass transformation temperature of the glass, α ２０－３００ = The linear thermal expansion coefficient of the glass at temperatures from 20°C to 300°C, where η ｌｉｑ = This is the liquid-phase viscosity of the glass, [Math 6] = Upper limit cooling point or the glass is 10 １３ The slope of the viscosity curve at a temperature where the viscosity η is dPas is T. １３ = The glass is 10 １３ This is the temperature at which the viscosity η of dPas is Glass articles (27).

16. The glass article (27) according to claim 15, wherein the glass article (27) is stretched glass, and preferably both sides are fire-polished.

17. The glass article (27) according to claim 15, wherein the glass article (27) is float glass.

18. The lateral dimension l of the aforementioned side surface (24, 26) ｘ ,l ｙ However, it is greater than 400 mm and / or the minimum lateral dimension l of the side surface. 最小（ｘ，ｙ） and the glass thickness d ガラス Regarding the ratio between the two, l 最小（ｘ，ｙ） / d ガラス >500, preferably >1000, particularly preferably >4000 This applies, A glass article (27) according to any one of claims 15 to 17.

19. The aforementioned glass is oxide-based and contains the following components in weight percent: SiO ２ 57 to 69, preferably 59 to 69, particularly preferably 61 to 69, however, the upper limit may preferably be 67. Al ２ O ３ 17 to 25, preferably 17 to 21, B ２ O ３ 0 to 7, preferably 0 to 5, particularly preferably 0 to 4.5, Li ２ O 3 to 5.5, preferably 3.5 to 5.5, Na ２ O 0.8 to 7, preferably 0.8 to 6, particularly preferably 0.8 to 5.5 Includes, Preferably, Al ２ O ３ and SiO ２ The total content of the elements is at least 75 to a maximum of 92, preferably a maximum of 90, based on the weight percentage. A glass ribbon (30) having a uniform thickness according to any one of claims 11 to 14, or a glass article (27) according to any one of claims 15 to 18.

20. The aforementioned glass is oxide-based and contains the following components in weight percent: SiO ２ 57 to 69, preferably 59 to 69, particularly preferably 61 to 69, however, the upper limit may preferably be 67. Al ２ O ３ 17 to 25, preferably 17 to 21, B ２ O ３ 0 to 7, preferably 0 to 5, particularly preferably 0 to 4.5, Li ２ O 3 to 5.5, preferably 3.5 to 5.5, Na ２ O 0.8 to 7, preferably 0.8 to 6, particularly preferably 0.8 to 5.5, K ２ O 0 to 1, preferably 0 to 0.8, particularly preferably 0 to 0.7, MgO 0 to 2, preferably 0 to 1.5, particularly preferably 0 to 1, CaO 0-4.5 SrO 0 to 2, preferably 0 to 1.5, particularly preferably 0 to 1, ZnO 0 to 3, preferably 0 to 2, particularly preferably 0 to 1.5, P ２ O ５ 0 to 3, preferably 0 to 2, particularly preferably 0 to 1.7, ZrO ２ 0 to 3, preferably 0 to 2, Includes, Furthermore, impurities and / or clarifying agents and / or coloring components may be present in amounts up to 2% by weight. A glass ribbon (30) having a uniform thickness according to any one of claims 11 to 14, or a glass article (27) according to any one of claims 15 to 18.

21. The aforementioned glass is oxide-based and contains the following components in weight percent: SiO ２ 62-72, preferably 65-70 Al ２ O ３ 7 to 14, preferably 8 to 12 B ２ O ３ 0.1 to 8.5, preferably less than 8.5 or 8 or less, preferably 4 to 7, particularly preferably 5 or more, and most particularly preferably greater than 5.5 Li ２ O 5 to 12, preferably 7 to 10 Na ２ O 0 to 2, preferably 0 to 1, particularly preferably 0.1 or more and / or less than 1, most particularly preferably 0.3 or more and / or less than 0.8 K ２ O 0 to 2, preferably 0 to 1 Includes, However, 0.8 < Li ２ O / (Li ２ O+K ２ O + Na ２ O) ≤ 1, A glass ribbon (30) having a uniform thickness according to any one of claims 11 to 14, or a glass article (27) according to any one of claims 15 to 18.

22. The aforementioned glass is oxide-based and contains the following components in weight percent: SiO ２ 55-75, preferably 62-72 Al ２ O ３ 18-27, preferably 18-23 Li ２ O 2.8 to 5, preferably 3 to 5 Na ２ O 0 to 4, preferably 0 to 2 K ２ O 0 to 4, preferably 0 to 2 MgO 0 to 8, preferably 0 to 4 CaO 0 to 4, preferably 0 to 2 SrO 0 to 4, preferably 0 to 2 BaO 0 to 4, preferably 0 to 2 ZnO 0 to 6, preferably 0 to 2 TiO ２ 0 to 4, preferably 0 to 3 ZrO ２ 0 to 5, preferably 1.2 to 4 B ２ O ３ 0 to 2, preferably 0 to 0.1 SnO ２ 0 to 2, preferably 0.05 to 1.6 Includes, Preferably, the component TiO ２ and ZrO ２ Regarding the total, 0 < Σ(TiO ２ + ZrO ２ ) < 9.5%, preferably 1.2 < Σ(TiO ２ + ZrO ２ ) < 9.5% This applies, or preferably, the component SnO ２ , ZrO ２ , and TiO ２ Regarding 0 ≤ SnO ２ / (ZrO ２ +TiO ２ ) < 0.8, preferably 0.01 ≤ SnO ２ / (ZrO ２ +TiO ２ ) < 0.7 This applies, A glass ribbon (30) having a uniform thickness according to any one of claims 11 to 14, or a glass article (27) according to any one of claims 15 to 18.

23. An apparatus for manufacturing a glass ribbon (30) having a uniform thickness by separating the edge region (5) from a glass ribbon (1) having a usable region (3) and an edge region (5) that is thicker than the usable region (3), wherein the apparatus comprises a stretching device for manufacturing a glass ribbon (1) from a molten glass (17), a cooling furnace (6), and a transport device (80) for transporting the glass ribbon (1) from the stretching device to the cooling furnace (6), wherein lasers (9, 10) are arranged in the cooling furnace (6) such that laser beams (90, 91) collide with the glass ribbon (1) perpendicular to the transport direction (8), and the collision points (11, 110) of the lasers are adjusted to be located in the boundary region between the usable region (3) and the edge region (5) on the glass ribbon (1).

24. The apparatus according to claim 23, wherein the lasers (9, 10) have at least one laser arm (15) positioned laterally within the cooling furnace (6), and the laser beams (90, 91) are deflected vertically by a deflection element (16) after exiting the lasers (9, 10).

25. The above device has the following features: - The apparatus has an imaging mirror as a deflection element (16), - The apparatus has a cooling device that actively cools the deflection element (16), - The apparatus includes at least one device for flushing the laser arm (15) with a flushing gas. - The laser arm (15) is movable and is formed to be removable from the cooling furnace (6), - The apparatus has a float tank (7) as a stretching device. - Rollers are used as the conveying device (8): The apparatus according to claim 24, having at least one of the following.

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