Component comprising glass or glass-ceramic, with pre-existing damage arranged along a predetermined dividing line and method for manufacturing the component

Description

[0001] Components comprising glass or glass ceramics that exhibit pre-damage along a given dividing line are known.

[0002] Such components can be manufactured in particular using the methods and devices described in the following documents: DE 10 2012 110 971 A1, DE 10 2015 110 422 A1, DE 10 2015 116 848 A1, DE 10 2015 111 491 A1, DE 10 2015 116 846 A1, DE 10 2015 111 490 A1, DE 10 2015 120 950 A1, DE 10 2016 102 768 A1, DE 10 2017 100 015.1, DE 10 2017 206 461.7, DE 10 2017 100 755.5, DE 10 2017 103 381.5, EP 2 754 524 A1, US 2005 / 0024743 A1, KR 101 407994 B1.

[0003] Further methods, devices and uses are known from EP 2 922 793 A1, DE 10 2014 116 957 A1, WO 2014 / 079478 A1 and US 2016 / 067822 A1.

[0004] From Zhang femtosecond pulsed laser irradiation inside a glass", DOI: 10.1103 / PhysRevB.71.024113 and Little Douglas J. et al.: "Structural changes in BK7 glass upon exposure to femtosecond laser pulses", DOI: 10.1002 / jrs.2770, alternative measurement methods for determining a material density are also known.

[0005] For thicker components, especially those with a thickness of 3.5 mm or more, the cutting edge after cutting along the specified cutting line exhibits poor quality and, in particular, high roughness. This regularly leads to increased scrap of the separated components.

[0006] Particularly for the glazing of vehicles, aircraft, or rail vehicles, advanced components made of glass or glass ceramic are in demand. Their cutting edges must exhibit high quality and, in particular, low roughness after cutting. It is essential that such components be produced cost-effectively with minimal waste and can be easily used in subsequent processing. Such components often comprise two different glass panes laminated with an intermediate plastic film and separated along at least one cutting line.

[0007] Thicker glass and glass-ceramic components (e.g. glass-ceramics based on lithium aluminum silicate), i.e. glass and glass-ceramic panes with a thickness of at least 3.5 mm, pose a challenge, especially during further processing: With conventional scoring processes, cuts are only possible along straight lines, from edge to edge. Tolerances of less than one millimeter are only possible with complex, multi-step processes, such as scoring, mechanical milling, and subsequent polishing. Particle-free surfaces cannot be guaranteed with current processes, meaning subsequent coatings require extensive cleaning of the glass and glass-ceramic substrates.

[0008] The object of the invention is to provide thicker components, in particular components with a thickness of at least 3.5 mm, comprising glass or glass-ceramic and having pre-damage along a predetermined parting line. These components, after separation along the predetermined parting line, exhibit better quality and a lower roughness of the parting edge, thus leading to less waste and allowing for easier use in further processing. Furthermore, the object of the invention is to find a method and device for producing such components and their preferred use.

[0009] The object is achieved by a component which has the features of claim 1: Component, comprising glass or glass ceramic, with pre-damages arranged along at least one predetermined dividing line, wherein the dividing line consists of a series of consecutive pre-damages, the pre-damages in the glass or in the glass ceramic are continuous, at least 90% of the pre-damages are cylindrically symmetrical, the glass or the glass ceramic has a material compaction of at least 1% compared to the actual material density in a radius of 3 µm around the longitudinal axis of the respective pre-damage, the relative weight loss per pre-damage is less than 10%, and the component has a thickness of at least 3.5 mm.

[0010] The component can preferably have a thickness of at least 5 mm, particularly preferably at least 8 mm. The component preferably has a thickness in the range of at least 3.5 mm to a maximum of 50 mm.

[0011] The inventors have recognized that for thicker components, especially for components with a thickness of at least 3.5 mm, it is necessary that the dividing line consists of a series of consecutive pre-damages and that the pre-damages in the glass or glass-ceramic must be continuous.

[0012] The more pre-damages are cylindrical, the better the underlying problem is solved. The inventors were able to show that at least 90% of the pre-damages must be cylindrically symmetrical. Preferably, at least 95% of the pre-damages are cylindrically symmetrical, more preferably at least 98%, and most preferably essentially all of the pre-damages are cylindrically symmetrical.

[0013] Furthermore, the inventors were able to demonstrate that the glass or glass-ceramic, within a radius of 3 µm around the longitudinal axis of the respective cylindrically symmetric pre-damage, exhibits a material densification of at least 1% compared to the actual material density, and the relative weight loss per pre-damage must be less than 10% to achieve the underlying problem. It is assumed that for thicker components with a thickness of at least 3.5 mm, it is necessary to perform the pre-damage in such a way that the density of the material increases by the amount of the pre-damage and as little material as possible is removed or lost (low weight loss).

[0014] The following measurement method was used to determine that the glass or glass-ceramic exhibits a material densification of at least 1% compared to the actual material density within a radius of 3 µm around the longitudinal axis of the respective cylindrically symmetric pre-damage: Lena Bressel, Dominique de Ligny, Camille Sonneville, et al. "Femtosecond laser induced density changes in GeO2 and SiO2 glasses: Fictive temperature effect [Invited]", Optical Materials Express, Vol. 1, No. 4, 605 613 (1 August 2011) DOI: 10.1364 / OME.1.000605. Evidence of the material densification was provided indirectly via a spectral shift of the Nd peak in the Raman spectrum. For this purpose, the Raman microscope had to have a spectral range of 10,000 cm -1 < so that the Nd luminescence would be detected at approximately 100 nm upon excitation at 488 nm.890 nm, and be equipped with suitable motorized XYZ stepper motor axes and a suitable microscope objective (NA > 0.7) to achieve a spatial resolution of less than one micrometer. The components according to the invention were scanned in the area to be measured using stepper motors. At each point, a Raman spectrum of the Nd peak was recorded. Its spectral position was recorded, and pressures and densities were calculated using standard spectra. These standard spectra were recorded from glass or glass-ceramic bodies that were compacted using belt presses. Further verification was possible using spatially resolved Brillouin spectra.

[0015] The relative weight loss per pre-damage is less than 10%, determined as follows (here, as an example, for a 2 mm thick soda-lime glass, which was reduced to a size of 150 × 250 mm² by manual scoring and breaking with a commercially available glass cutter): Particles, fingerprints, and other contaminants were removed by cleaning both sides with glass cleaner, ethanol, and compressed air, either manually or in an automated cleaning process (washing machine). The prepared sample was then weighed on a precision balance (Mettler Toledo AB204-S). The entire setup was enclosed in a transparent plastic box to increase measurement accuracy. The sample was then mounted on the holder of an XY-axis system (Aerotech Inc., 3D Micromac microSTRUCT). It was aligned using two stops and secured against slipping with commercially available adhesive tape.Laser processing was performed using a Lumera HyperRapid at a wavelength of 1064 nm and a pulse energy of 400 µJ. A 16 mm biconvex lens (Thorlabs, Inc.) was also used. The distance between the lens and the sample was adjusted so that the focal point was 1.6 mm below the surface. At a laser frequency of 100 kHz, the glass sample was accelerated to a speed of 1 m / s in the x-direction. After a defined acceleration distance, the laser aperture was opened for a distance of 90 mm, creating a separation line consisting of a series of 9,000 consecutive pre-damage marks spaced 10 µm apart. The glass sample was then moved 10 µm in the y-direction, and the entire laser process was repeated 16,000 times. This produced a two-dimensional grid of pre-damages with a size of 90 × 160 mm 2< (see . Figure 4). The adhesive tape was then removed and the sample weighed again. To rule out any falsification of the measurement result that could be caused by particle deposition during the laser process, the previously mentioned cleaning steps (glass cleaner, ethanol, compressed air) or automated cleaning procedure were performed one more time and the sample weighed again.

[0016] The following calculation rule was used to calculate the relative weight loss per hole: The theoretical weight loss per pre-damage, if the complete material of the pre-damage were removed from the sample, is calculated as follows: m theo = π 4 d 2 hρ d: Diameter of the cylindrical pre-damage, determined from SEM images of fracture edges along the pre-damage h: Glass thickness ρ : Density of the sample, from material data sheet

[0017] The actual weight loss m actualper pre-damage is obtained if the measured weight loss m measurement by the number of previous injuries N is shared: m actual = m mess N

[0018] The relative mass loss is determined by forming the quotient: m rel = m actual m theo

[0019] Here is an example for a 2 mm thick glass: With a sample thickness of h = 2 mm and a density of ρ = 2.5 g / cm 3< as well as a determined hole diameter of d = 600 ± 60 nm, this results in a theoretical mass loss of m theo = 1413 ± 283 pg per pre-damage (for sample thicknesses of at least 3.5 mm, the values ​​can be determined accordingly).

[0020] The actual weight loss results at m mess = 6 ± 1 mg and N = 5.8·10 7< to m actual = 104 ± 17 pg per pre-damage.

[0021] The relative weight loss is calculated as 7.4 ± 2.7%. All calculations take error propagation into account.

[0022] The edge roughness of a component according to the invention, which is cut along the specified parting line, can be determined, for example, using the following methods and leads to comparable results: Topography determination on glasses, glass-ceramics, ceramics, metals, plastics, and composites using white light interference microscopy; high-resolution determination of surface topography on glasses, glass-ceramics, ceramics, metals, plastics, composites, and solids using atomic force microscopy; tactile using a profilometer; Peter de Groot, Principles of interference microscopy for the measurement of surface topography, Advances in Optics and Photonics 7, 1–65 (2015).

[0023] The intersection surfaces of the pre-damaged areas with at least one surface of glass or glass ceramic are preferably circular. The radii of the intersection surfaces are preferably substantially equal.

[0024] The ratio of the difference in the hole diameter of the pre-damage on the surface do of the component and the underside of the component du to the thickness of the component h is preferably T = |do -du | / (2h) < 0.001, particularly preferably T < 0.0001.

[0025] The component preferably consists of several layers, whereby the layers consist of the same material or of different materials.

[0026] Preferably, the component is separated or separable along the predetermined dividing line. Particularly preferably, the component is separated or separable along the predetermined dividing line under the influence of mechanical or thermal stress.

[0027] Preferably, the component is glazing for a means of transport or a part thereof or is used for this purpose.

[0028] The component is preferably used for the production of glazing for means of transport, in particular for the production of front, rear, roof or side glazing.

[0029] In order to produce a component according to the invention, the pre-damages in the glass or glass ceramic are generated by means of a 0th order Bessel beam.

[0030] The device for producing the component comprises optical means for generating a 0th order Bessel beam to create the pre-damage.

[0031] The following describes how and why, in a component according to the invention, the pre-damage in the glass or in the glass ceramic is preferably generated by means of a 0th order Bessel beam.

[0032] The 0th-order Bessel beam is preferably a pulsed laser beam. The intensity of the laser pulse along the optical axis preferably exceeds a threshold of 5 × 10 16 W / m 2 .

[0033] By using an optical beam-shaping system in combination with a pulsed laser with a peak power of less than 200 MW, a Gauss-Bessel-shaped "line-shaped" intensity distribution is generated along the optical axis, which generates a threshold intensity of at least 5 × 10 16 W / m 2 across the entire glass or glass-ceramic thickness (thickness in particular of at least 3.5 mm, preferably at least 6 mm, most preferably at least 8 mm). Experiments have shown that this intensity is required to create pre-damage (microchannel) with a diameter of approximately 1 µm and a continuous length across the entire glass or glass-ceramic thickness.

[0034] To achieve these requirements, several conditions must be met. 1) With the help of beam-shaping optics (e.g. with an axicon system), the laser power is predominantly fed radially into the line-shaped intensity distribution (approximately analytically describable by a Gauss-Bessel intensity distribution I(r,z). This ensures that non-linear absorption mechanisms until the plasma explosion essentially only take place within the line-shaped intensity distribution. 2) The length L of the line-shaped intensity distribution must extend at least 0.5 mm beyond the thickness h of the dielectric material on both surfaces ( Figure 5 ). 3) The axial intensity distribution ( Figure 6) must be greater than approximately 5 × 10 16< W / m 2< within glass or glass-ceramic. It should be distributed as homogeneously as possible so that its value does not fall below this threshold. On the other hand, it should not deviate from the threshold by more than 20%. 4) In order for this threshold to be available in the smallest possible transverse range, it is necessary that the threshold is reliably reached only on the optical axis in the 0th order diffraction maximum; it is very advantageous that this radius is thereby significantly smaller than the radius of the first dark diffraction ring. On the other hand, the intensity must not be so high that the 1st diffraction ring reaches this threshold ( Figure 7). This would lead to a massive, but undesirable enlargement of the perforation channel (not to mention the increased power requirement). This means that the maximum intensity is not higher than a factor of 6.16 of the threshold intensity. 5) In order to develop the longest possible pre-damage (microchannel), fluence F and intensity I along the optical axis must be in an optimal ratio ( Figure 8). It has been shown that 6 × 10 10< < I / F < 1 × 10 12< , preferably 1.25 × 10 11< < I / F < 2.5 × 10 11<. 6) This pre-damage (microchannels) is characterized by the fact that it results in extremely low weight and volume loss. It has been shown that the pre-damage (microchannels) introduced according to the above requirements is such that it is caused primarily by compaction of the material and not by evaporation. This means that after laser bombardment, more than 95% of the hole volume, preferably more than 98%, remains in the glass or glass-ceramic.

[0035] In this way, long pre-damages with a diameter of < 1 µm can be created in components made of glass or glass ceramic, even with a thickness of > 3.5 mm.

[0036] The required laser peak power and the beam shaping system are presented in an example (two examples are shown in the Figures 5 to 8 shown).

[0037] Comparison example with a laser with a peak power of 20 MW, a pulse width of 10 ps and a spherical lens for beam shaping, which, however, does not produce a continuous microperforation over a length of 8 mm. Comparison example: Component less than 3.5 mm thick. Laser type: ND-YAG, 1064 nm, pulsed, repetition rate 200 kHz. Pulse width (FWHM): 10 ps. Pulse energy: 200 µJ to 300 µJ. Pulse shape: Single pulse or pulse sequence with 10 to 50 ns intervals. Pulse energy decreases monotonically within the pulses, possibly remaining constant. In the application example: 4 pulses spaced 20 ns apart, pulse energy decreases. Beam-shaping optics: 16 mm biconvex lens, Thorlabs; illuminated with a 12 mm beam diameter.

[0038] Preferred generation of linear damage in a 10 mm thick soda-lime glass with a fracture edge. Laser peak power and pulse duration are selected according to the optics used so that the described requirements 5) and 6) are met. The requirements for the process can be met, for example, with a laser that emits 10 ps short pulses at an average power of more than 110 W, a wavelength of 1064 nm, a pulse count greater than or equal to 1, a glass thickness of 10 mm, a beam radius (beam waist) at entry into the glass of < 5 mm, and a refractive index of the glass of 1.5.

[0039] Thick glass and glass-ceramic substrates with predefined parting lines could, on the one hand, enable greater cutting precision: the cut and final dimensions largely match. On the other hand, existing process chains, especially for coated glass and glass-ceramics, as well as laminated glass panes, could be significantly simplified.

[0040] Another application is waste reduction: green glass that can be converted into a glass ceramic, which can be cut using the predefined dividing lines based on an image processing measurement in such a way that the cuts omit areas with defects.

[0041] Another application is the cutting of stacks with a thickness of at least 3.5 mm, ie the provision of a stack of one or more glass substrates, each of which has a thickness of less than 3.5 mm, with pre-damage in one process step. Examples of implementation

[0042] Component: glass plate Geometry [length × width × thickness] 50 mm × 50 mm × 3.6 mm Material: Borosilicate glass Cylindrical pre-damage: - Geometry cylindrical pre-damage: [diameter × length] 700 nm × 3.6 mm - Percentage of previous cyl. damage: 99 % - Distance between previous damage 7 µm Average density increase in diameter of 3 µm: 1,9 % Edge roughness 1 µm Relative weight loss 1,0 % Component: glass ceramic plate Geometry [length × width × thickness]: 50 mm × 50 mm × 4.1 mm Material: Lithium aluminum silicate glass ceramic Cylindrical pre-damage: - Geometry cylindrical pre-damage: [diameter × length] 600 nm × 4.1 mm - Percentage of previous cyl. damage: 99,5 % - Distance between previous damage 4 µm Average density increase in diameter of 3 µm: 1,5 % Edge roughness 0,5 µm Relative weight loss 0,5 % Component: Glass-plastic laminate Geometry [length × width × thickness]: 50 mm × 50 mm × 3.6 mm Material [length × width × thickness]: Soda lime glass [50 mm × 50 mm × 2.3 mm] Plastic film [50 mm × 50 mm × 0.8 mm] Thermally toughened aluminosilicate glass [50 mm × 50 mm × 0.5 mm] Cylindrical pre-damage: - Geometry cylindrical pre-damage [diameter × length]: < 1 µm × 3.6 mm - Percentage of previous cyl. damage: 99,5 % - Distance between previous damage 5 µm Average density increase in the radius of 3 µm: Soda-lime glass: 1.6% Thermally toughened aluminosilicate glass: 1.7% Edge roughness 1 µm Relative weight loss 0,5 % Geometry [length × width × thickness]: 100 × 200 × 6,1 Material [length × width × thickness]: Soda lime glass [100 mm × 200 mm × 2.75 mm] Plastic film [100 mm × 200 mm × 0.6 mm] Soda lime glass [100 mm × 200 mm × 2.75 mm] Cylindrical pre-damage: - Geometry cylindrical pre-damage [diameter × length]: <1 µm × 6 mm - Percentage of previous cyl. damage: 99,5 % - Distance between previous damage 5 µm Average density increase in the radius of 3 µm: 1,6 % Edge roughness 1 µm Relative weight loss 0,5 %

[0043] The following laser parameters were used, for example, to produce components according to claim 1: Laser type: ND-YAG, 1035 nm, pulsed, repetition rate 1 to 300 kHz. Pulse width (FWHM): 10 ps. Pulse energy: 900 µJ. Pulse shape: Single pulse or pulse sequence spaced 14 ns, 2 ns, and 14 ns apart; constant pulse energy. In the application example: 4 pulses spaced 20 ns apart, with decreasing pulse energy. Beam-shaping optics: Fused silica axicon with a 20° cone angle (140° apex angle).

[0044] The travel speed v results from the repetition rate R and the desired distance L between the individual modifications to v = L × R; e.g., v = 10 µm × 100 kHz = 1000 mm / s.

[0045] Figure 1a shows a schematic plan view of an enlarged section of a 3.8 mm thick floated borosilicate glass with pre-damages arranged along a given dividing line. The pre-damages are cylindrically symmetrical. Within a radius of 3 µm around the longitudinal axis of the respective cylindrically symmetric pre-damage, the material exhibits a densification of at least 1% compared to the actual material density. The relative weight loss per pre-damage is less than 10%. The pre-damages are spaced approximately 7.14 µm apart along the dividing line.

[0046] Figure 1b shows the edge view of the component Figure 1a after it is separated along the dividing line.

[0047] Figure 1c shows a schematic side view of various cylindrically symmetrical pre-damages.

[0048] Figure 2a shows in plan view, Figure 2b a side view of a component according to the invention (photographs).

[0049] Figure 3 shows a top view of a section of a 3.8 mm thick floated borosilicate glass with pre-damages arranged along a given dividing line, the pre-damages are not cylindrically symmetric, within a radius of 3 µm around the longitudinal axis of the respective cylindrically symmetrical The pre-damages are spaced from each other by approximately 7.18 µm along the dividing line.

[0050] Figure 4 shows a 2D grid formed from the cylindrical pre-damages from which the weight loss was determined.

Claims

1. Component comprising glass or glass-ceramic, having occurrences of prior damage which are arranged along at least one predetermined separation line, characterised in that the separation line comprises a series of occurrences of prior damage which are located one behind the other, the occurrences of prior damage are continuous in the glass or glass-ceramic, at least 90% of the occurrences of prior damage are cylindrically symmetrical, the glass or glass-ceramic in the radius of 3 µm about the longitudinal axis of the respective prior damage has a material compaction of at least 1% with respect to the actual material density, the relative weight loss per occurrence of prior damage is less than 10%, wherein the relative weight loss per occurrence of prior damage is calculated as a quotient of a measured weight loss per occurrence of prior damage and a theoretical weight loss per occurrence of prior damage when the complete material of the occurrence of prior damage would have to be removed from the component, and the component has a thickness of at least 3.5 mm.

2. Component according to claim 1, characterised in that the material compaction is calculated based on a position of a luminescence peak of a Raman spectrum of a Raman microscopy exposure of the respective prior damage and based on standard spectrums for different material densities.

3. Component according to any one of the preceding claims, characterised in that the intersections of the occurrences of prior damage with at least one surface of glass or glass-ceramic are circular.

4. Component according to claim 3, characterised in that the radii of the interfaces are substantially identical.

5. Component according to any one of the preceding claims, characterised in that the ratio of the value difference of the hole diameter of the prior damage at the surface do of the component and the lower side of the component du with respect to the thickness of the component h is T = |do-du| / (2h)< 0.001.

6. Component according to any one of the preceding claims, characterised in that the component comprises a plurality of layers, wherein the layers comprise the same material or different material.

7. Component according to any one of the preceding claims, characterised in that it is separated along the predetermined separation line.

8. Component according to claim 7, characterised in that it is a glazing for a means of transport or part thereof.

9. Method for producing a component having a thickness of at least 3.5 mm, comprising glass or glass-ceramic, having occurrences of prior damage which are arranged along at least one predetermined separation line, characterised in that the separation line is produced from a series of occurrences of prior damage which are located one behind the other, wherein the occurrences of prior damage are produced by means of a zero order Bessel beam, and wherein the occurrences of prior damage in the glass or in the glass-ceramic are constructed continuously, wherein at least 90% of the occurrences of prior damage are configured in a cylindrically symmetrical manner, wherein the glass or glass-ceramic in the radius of 3 µm about the longitudinal axis of the respective prior damage is provided with a material compaction of at least 1% with respect to the actual material density, wherein a relative weight loss per occurrence of prior damage is provided to be less than 10%, wherein the relative weight loss per occurrence of prior damage is calculated as a quotient of a measured weight loss per occurrence of prior damage and a theoretical weight loss per occurrence of prior damage when the complete material of the occurrence of prior damage would have to be removed from the component.

10. Method according to claim 9, characterised in that the material compaction is calculated based on a position of a luminescence peak of a Raman spectrum of a Raman microscopy exposure of the respective prior damage and based on standard spectrums for different material densities.

11. Means of transport having a component according to any one of the preceding claims 1 to 8.