PANE-SHAPED GLASS ELEMENT AND METHOD OF SEPARATING A GLASS SUBSTRATE INTO A PLURALITY OF SUCH GLASS ELEMENTS

Abstract

A pane-shaped glass element having two opposing side surfaces which are edge-wise interconnected by a number of edge surfaces, wherein in the or each edge surface there are provided filamentary damages forming side-by-side elongate depressions, and wherein the or each edge surface lies obliquely to the side surfaces, is to be further formed for particularly good usability in a plurality of possible applications. For this purpose, according to the invention, the respective edge surface has a surface roughness with a mean roughness value of at least 0.3 μm, and preferably of at most 2 μm, in a particularly advantageous embodiment of about 1 μm, in its region provided with the filamentary damages.

Claims

1-7. (canceled).

8. A pane-like glass element having two opposing side surfaces which are edgewise interconnected by a number of edge surfaces, wherein in the or each edge surface there are provided filamentary damages forming juxtaposed, elongate depressions, and wherein the or each edge surface lies obliquely relative to the side faces, wherein the respective edge surface has a surface roughness with a mean roughness value of at least 0.3 μm in its region provided with the filamentary damages, characterised in that the edge surface is inclined by an angle of inclination of 0.5° to 3° relative to the surface normal of the side surfaces.

9. The pane-like glass element of claim 1, the respective edge surface of which has, in its region provided with the filamentary damage, a surface roughness with a mean roughness value of at most 2 μm, advantageously of about 1 μm.

10. The pane-like glass element of claim 1, which has a thickness of at most 6 mm, preferably at most 3 mm.

11. The pane-like glass element of claim 9, which has a thickness of at most 6 mm, preferably at most 3 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] An embodiment of the invention is explained in more detail with reference to a drawing. Shown therein is:

[0022] FIG. 1 illustrates a schematic of a cutting system for cutting glass elements.

[0023] FIG. 2 illustrates a schematic section of a glass substrate with inserted filaments.

[0024] FIG. 3 illustrates a glass element.

DETAILED DESCRIPTION OF THE INVENTION

[0025] Identical parts are marked with the same reference signs in all figures.

[0026] The cutting system 1 according to FIG. 1 is intended for cutting glass substrates 2 by laser filament cutting. For this purpose, the cutting system 1 comprises a perforation laser 4 designed for filament cutting, which laser can be controlled via an associated control device 6. Via the control by means of the control device 6, the focal point of the perforation laser 4 can be guided along a predeterminable cutting line 8 on the surface of the glass substrate 2 to be cut. As a result of the design of the perforation laser 4, local heating in the glass material occurs at the point where the focal point is located, and so occurs the formation of local stresses and a change in the refractive index, so that ultimately, as a result of non-linear optical effects, so-called filaments are formed in the glass material along the cutting line 8, which form the desired perforation 10.

[0027] For the actual cutting of the glass substrate 2, hence for its separation into individual glass elements 12, i.e. for the separation of the parts along the cutting line 8 and the perforation 10, a breaking process is provided subsequent to the filamentation, i.e. after the insertion of the perforation 10. To facilitate or support the disunion or separation of the glass elements 12 from each other, the introduction of thermal or mechanical stresses in the vicinity of the introduced perforation 10 of the glass substrate 2 is provided. For this purpose, in the example embodiment, the glass substrate 2 is locally heated in a region in the vicinity of the perforation 10 after the filaments forming the perforation 10 have been introduced; alternatively, however, local cooling could also be provided. In the example embodiment, a heating device 14 that can be positioned locally relative to the surface of the glass substrate 2 is provided for the purpose of local heating.

[0028] The cutting system 1 is designed to facilitate the removal or separation of the glass elements 12 produced during separation. In particular, the knowledge is taken into account that in principle a gap-free separation is produced during perforation or modification laser cutting. If the glass elements 12 are then to be separated from each other or from the surrounding bulk material, this is often not possible without causing damage. Furthermore, separation and removal is made more difficult with increasingly complex cutting patterns such as radii, corners or polygons. Typical removal damages are shells, chipping or cracks at the separation edges. In order to counteract this and to facilitate the removal or separation of the glass elements 12, the perforation laser 4 is adjusted for an inclined impingement of the laser beams on the glass substrate 2 relative to the surface normal of the glass substrate, indicated by the arrow 16, when the filaments forming the perforation 10 are introduced.

[0029] This oblique or inclined impingement of the laser beams results in the filamentary damage produced in the glass substrate 2 also being inclined or oblique to the surface normal of the glass substrate 2. This is shown schematically in FIG. 2. As can be seen there, the laser pulses 18 arriving at an angle α relative to the surface normal of the glass substrate 2 are refracted in the glass substrate 2. Due to the light refraction, the light propagates within the glass substrate 2 at a refractive index n of the material of the glass substrate 2 with an angle β relative to the surface normal, which can be derived from the angle of incidence of the laser pulses 18 according to the relationship sin ß=(1/n) sin α. Consequently, obliquely incident laser pulses 18 also cause oblique modifications or filamentary damage in the glass substrate 2.

[0030] During the subsequent breaking or separating of the glass substrate 2, glass elements 12 with sloping or inclined edge surfaces 20 are accordingly produced. As can be seen from the enlarged sectional representation in FIG. 3, the result of the separation process is thus a pane-shaped glass element 12 with two opposing side surfaces 22, which are connected to each other edgewise by a number of edge surfaces 20. The edge surface 20 is tilted or inclined by the angle of inclination β with respect to the surface normal of the side surface 22, i.e. it runs obliquely with respect to the side surfaces 22. As a result of the process and production, filamentary damages 24 forming elongated depressions running next to one another are present in the edge surface 20 as relics of the perforation 10 previously made in the glass substrate 2.

[0031] In addition to the facilitation of removal and separation achieved by the inclined orientation of the edge surface 20, the glass element 12 is designed for particularly good usability in a variety of possible applications. This is based on the realization that the beveled edge surface 20 can be specifically refined in the sense of providing additional functionalities, in this case in particular optical recognizability and/or bondability. In order to achieve this, the edge surface 20 has a surface roughness with a mean roughness value of approximately 1 μm in its area provided with the filament-shaped damages 24.

[0032] The intended surface roughness is set during the filamentation step by suitable parameter selection and process control. In particular, the number, the dimensioning, the position and also the design of the filaments are essential parameters for the resulting surface roughness, and they are suitably selected and adjusted according to the desired surface roughness. Furthermore, it is also conceivable to introduce deliberately pronounced (e.g. particularly large or small, . . . ) modifications at fixed intervals in addition to the normal ones in order to achieve the desired surface roughness.

[0033] For the sake of improved comprehensibility, in particular with regard to the angle of inclination of the edge surface 20, the illustration in FIG. 3 is to be understood merely as a schematic sketch and is not to scale. With regard to its dimensions and geometrical parameters, the glass element 12 is rather designed in the example embodiment with a comparatively small angle of inclination β of the edge surface 20 with respect to the surface normal of the side surfaces 22 of about 2°. This takes account of a large number of design criteria in a particularly favorable manner. In particular, such a choice of the angle of inclination β can, on the one hand, form a sufficient removal slope facilitating removal or separation, whereby, on the other hand, interfering effects such as stray light due to edge damage such as shells can be kept particularly low when light is coupled in, e.g. for displays. Due to the intended surface roughness of the edge surface, it is nevertheless possible to provide significantly improved visual recognition and also improved adhesiveness, especially for the comparatively small inclination angles β provided.

[0034] List of reference signs

[0035] 1 cutting system

[0036] 2 glass element

[0037] 4 perforation laser

[0038] 6 control device

[0039] 8 cutting line

[0040] 10 perforation

[0041] 12 glass element

[0042] 14 heating device

[0043] 16 arrow

[0044] 18 laser pulse

[0045] 20 edge surface

[0046] 22 side surface

[0047] 24 damage