DEVICE AND METHOD FOR FORMING A STRUCTURED FUNCTIONAL COATING ON A LAYER OF CURVED GLASS

Description

[0001] The invention relates to a device and a method for producing a structured functional coating for a glass layer. Background of the invention

[0002] For example, German patent DE 103 16 576 B3 discloses a method and apparatus for manufacturing soft contact lenses. This method is based on specific steps for hydrating and desalting a soft contact lens, followed by laser ablation of lens material to produce so-called multifocal lenses. Furthermore, US patent application 2009 / 242 527 A1 discloses a method for removing a scratch-resistant or anti-reflective coating to provide improved adhesive retention of a lens in rimless eyeglasses.

[0003] Using the example of the production of a conventional vehicle windshield, some problems that individually and in combination gave rise to the invention will be presented below.

[0004] To meet aerodynamic and stylistic requirements, many vehicle windows are curved. Vehicle windows also incorporate a variety of functions, such as window heating, antennas, sensors, etc.

[0005] To provide, for example, an electric heater, thin electrically conductive layers are applied using known techniques such as screen printing or vapor deposition.

[0006] In existing manufacturing processes, such as those described in EP 3 034 295 A (basis for the preamble of claims 1 and 7), the electrically conductive layer is first applied to a flat glass disc and then structured. Only small areas, approximately 15 cm x 15 cm, can be processed in a single step. If larger areas need to be structured, overlaps and offsets generally occur at the edges, resulting in steps and jumps in the structured edges.

[0007] To bend a glass pane, it must be heated to relatively high temperatures, e.g., 600°C. Since the electrically conductive layer would react with the surrounding atmosphere at these temperatures, the coating must be completely protected by a protective layer, e.g., NaSO₄, before bending.

[0008] However, it has been shown that this protection is insufficient, so reactions still occur, especially in the edge area of ​​the structured functional coating.

[0009] Another problem is that, under the influence of heat, the electrically conductive layer is often heated to such an extent that flow processes occur, particularly in the edge region of the structured functional coating. Therefore, the structural integrity of the functional coating is compromised.

[0010] Furthermore, both influences can impair the optical properties. For example, perceptible optical distortions can occur in the edge area of ​​the functional coating.

[0011] After bending, the protective layer must be painstakingly and completely removed again.

[0012] Starting from this situation, it is an object of the invention to provide a device and a method that makes it possible to provide curved glass layers cost-effectively and with high precision, which have a structured coating. Brief description of the invention

[0013] The problem is solved by a device for producing a structured functional coating on a first curved glass layer, see claim 1. The device comprises a holder for receiving the first curved glass layer, at least one laser, and a steering unit. The steering unit is provided for directing the laser beam across the functional coating so that portions of the functional coating are ablated to structure the functional coating.

[0014] This device now makes it possible to bend the glass layer first and only then apply the structuring. This also allows the application of functional coatings to be shifted to a point after bending. Therefore, the application of a protective layer before bending and its removal after bending are no longer necessary. This not only prevents potential reactions during bending but also results in the potential elimination of process steps.

[0015] In one embodiment of the invention, the steering unit is designed to move the laser relative to the surface of the functional coating. This enables cost-effective manufacturing.

[0016] According to the invention, the distance between the laser and the functional coating is approximately 0.5 m to 2 m. Due to this relatively large distance, the focal area can be adjusted so that minor deviations in the shape of the glass layer and / or the coating have no significant impact on the structuring. This eliminates the need for complex distance measurements in the production process.

[0017] According to a further embodiment of the invention, the laser provides pulsed laser radiation with a power of 100 watts or more. This allows the necessary power for structuring to be applied even over distances of several meters, thus keeping production times short.

[0018] According to a further embodiment of the invention, the laser light has a wavelength of 355 nm, 532 nm or 1064 nm. This allows the use of conventional lasers.

[0019] In a further embodiment of the invention, the laser provides pulsed laser radiation with a period of a few nanoseconds to a few picoseconds. This allows not only small but also large structures to be ablated.

[0020] According to a further embodiment of the invention, the laser is a CO2 laser. Therefore, conventional lasers can be used.

[0021] The problem is also solved by a method for producing a glass pane (see claim 7) which includes the step of obtaining a first glass layer, wherein the first glass layer has at least a section of a functional coating. Furthermore, the method includes the step of structuring the functional coating on the first glass layer by means of laser ablation.

[0022] This avoids a possible reaction during bending.

[0023] In one embodiment of the invention, the functional coating is applied after the glass layer has been bent. This means that the method now makes it possible to bend the glass layer first and only then apply the structuring. Thus, the step of applying functional coatings can also be shifted to a point in time after bending. Therefore, the application of a protective layer before bending and the removal of the protective layer after bending can be omitted.

[0024] In a further embodiment of the invention, the structuring step involves the spatial displacement of a laser relative to the functional coating. This enables cost-effective manufacturing.

[0025] According to a further embodiment of the invention, the inventive method can further comprise the step of obtaining a second glass layer, wherein the first glass layer and the second glass layer are correspondingly bent, the step of inserting a combination film between the functional coating on the first glass layer and the second glass layer, and the step of thermally bonding the glass layers by means of the combination film. That is, the method can also be used for the production of laminated glass panes. Brief description of the drawings

[0026] Embodiments of the present invention are described by way of example with reference to the attached drawings, which show: Fig. 1 a schematic representation of embodiments of devices according to the invention, Fig. 2 a schematic sectional view of glass panes produced according to the method according to the invention, Fig. 3 a schematic representation of one aspect of embodiments of devices according to the invention, Fig. 4 another schematic representation of one aspect of embodiments of devices according to the invention, and Fig. 5 a flowchart with steps according to the method according to the invention. Detailed description of the invention with reference to the drawings

[0027] The invention will be described in more detail below with reference to the figures.

[0028] Furthermore, for the sake of simplicity, reference will generally be made to only one entity at a time. Unless explicitly stated otherwise, the invention may also include several of the entities concerned. Therefore, the use of the words "a", "an", and "a" should only be understood as an indication that at least one entity is used in a simple embodiment.

[0029] In the procedures described below, individual steps can be embodied in a single step and, for example, executed in parallel. Furthermore, the sequence of procedure steps can vary, so the presented sequence of steps should not be considered mandatory unless a specific sequence is explicitly described as necessary.

[0030] In Figure 1Figure 1 shows a schematic representation of embodiments of devices according to the invention for producing a structured functional coating 5 on a first curved glass layer 2.

[0031] The device 20 has a holder 10 for receiving the first curved glass layer 2. This can be shaped, for example, as a frame for a specific type of glass layer 2 or a variety of types of glass layers 2.

[0032] The holder 10 can have one or more holding devices 13, for example, at its edge and / or inside. Holding devices 13 can be designed, for example, as clamps or as vacuum chambers. Vacuum chambers are particularly advantageous, as they allow the glass layer 2 to be held quickly and reliably at a multitude of points. The holder 10 is preferably shaped such that the respective glass layer 2 is held essentially stress-free. For this purpose, the holder 10 has a shape substantially adapted to the shape of the curved glass layer with low tolerances in the contact area, preferably less than ±0.5 mm, and particularly preferably less than ±0.2 mm.

[0033] Furthermore, the device 20 comprises at least one laser 11 and a steering unit 12. The steering unit 12 is designed to direct the laser beam 11 across the functional coating 5, so that portions of the coating 5 are removed to structure it. This removal of the coating 5 can be achieved either by direct irradiation of the coating 5 or by indirect irradiation of the coating 5 through the glass layer 2. Thus, the device 20 now makes it possible to bend the glass layer first and then apply the structuring.

[0034] Therefore, the step of applying functional coatings 5 ​​can also be shifted to a point in time after bending. Consequently, the application of a protective layer before bending and the removal of the protective layer after bending can be omitted.

[0035] Since the structuring only takes place after bending, the problems previously encountered, such as reactions at the structured edges and changes in the optical properties of the structures due to heating, are avoided.

[0036] Furthermore, if the application of the functional coating 5 is postponed to a point in time after bending, the process steps of applying a protective layer before bending and removing the protective layer after bending can also be removed from the manufacturing process, resulting in a time and cost advantage.

[0037] Depending on the design of the device 20, one or more lasers 11 can be provided. These lasers 11 can be arranged differently in space and / or have different optical properties, such as pulse duration, wavelength, and power.

[0038] Insofar as the invention refers to structuring the coating 5, this includes any type of structuring, but in particular complete ablation to create larger free areas, line-like ablation to create, for example, conductor-like structures such as heating wires and / or antennas, as well as the creation of grid-like structures. The width of the structuring of the coating 5 is typically 100-150 µm or greater. Furthermore, insofar as the invention refers to functional coatings, this includes, in particular, electrically conductive coatings, such as silver-containing layers. Another functional coating is, for example, a low-E coating. The essential requirement here is only that there is a suitable laser 11 that can ablate the respective coating 5.

[0039] It can readily be provided that the focus position of laser 11 is automatically corrected, so that precise structuring can be achieved without additional displacement of laser 11 relative to the glass layer 2 or coating 5. For example, the focus position can have a tolerance of + / -5 mm, so that, for example, the bending tolerance of a curved glass layer 2 can be well compensated.

[0040] Different principles can be applied as the steering unit 12 within the meaning of the invention, as shown in the Figure 3 and 4 Illustrated by example.

[0041] According to the invention, a steering unit 12 in the form of a tilting mirror is provided for a laser 11 (or a plurality of lasers 11). Depending on the degrees of freedom of the carriage, as an example of a steering unit 12 in Figure 3This allows the curved (shown concave) surface of a glass pane 1 with a functional coating 5 oriented towards the laser beam to be scanned in one or more directions. The functional coating can then be structured by appropriately controlling the movement of the steering unit and the laser 11.

[0042] According to the invention, alternatively or additionally, a steering unit 12 in the form of a one-, two-, or three-dimensionally displaceable slide is provided for a laser 11 (or a plurality of lasers 11). Depending on the degrees of freedom of the mirror, as an example of a steering unit 12 in Figure 4This allows the curved (shown concave) surface of a glass pane 1 with a functional coating 5 oriented towards the laser beam to be scanned in one or more directions. The functional coating can then be structured by appropriately controlling the movement of the steering unit and the laser 11.

[0043] Mixed forms can also be provided here without any problem.

[0044] If only a small number of lasers 11 with a fixed position relative to the holder 10 are used, this is advantageous because then there are fewer boundary areas with overlap and offset.

[0045] Limiting areas arise when a laser needs to be moved relative to its scan field to achieve a larger structured area. Since there is a certain tolerance in both the thickness of the glass layer 2 and the functional coating 5, and additional play occurs during the movement from one position to another, a certain overlap must be factored in. These tolerances also result in a slight offset.

[0046] According to the invention, the distance d between the laser 11 and the functional coating 5 is as shown in Figure 1 The path length is approximately 0.5 m to 2 m. The path length d does not necessarily have to be linear; one or more deflection elements can be incorporated into the beam path. d denotes the path length that a light beam travels after leaving the laser 11 until it strikes the functional coating 5 to be structured.

[0047] Due to the relatively large distance d between laser 11 and functional coating 5, the focal area can be adjusted so that minor shape deviations of the glass layer 2 and / or the coating 5 have no significant impact on the structuring. This allows the production process to function without complex distance measurements. Furthermore, the relatively large distance enables the scan field to be so large that laser 11 does not need to be moved relative to the area to be structured; instead, the laser beam can be guided solely by a steering unit 12 (according to the distance d). Figure 3 The scan is performed over the entire area, e.g., 150 cm x 150 cm. The scan field is preferably larger than 150 mm x 150 mm, e.g., larger than 1000 mm x 1000 mm.

[0048] By appropriately arranging, for example, two lasers in relation to a vehicle windshield, one laser can be used for structuring a right part of the vehicle windshield, while the other laser can be used for structuring the left part of the vehicle windshield.

[0049] Obviously, the duration of the structuring process can be reduced by using multiple lasers 11 and associated steering units 12. Preferably, however, the lasers 11 are each stationary with respect to the area to be structured, so that overlap or offset does not occur.

[0050] Lasers 11 according to embodiments of the invention provide pulsed laser radiation with a power of 100 watts or more. According to one embodiment of the invention, the light of the laser 11 has a wavelength of 355 nm, 532 nm, or 1064 nm and / or the laser 11 provides pulsed laser radiation with a period of a few nanoseconds to a few picoseconds. This means that commercially available lasers, such as CO₂ lasers or Nd:YAG lasers, can be used.

[0051] Suitable pulse rates for laser 11 are greater than 100 kHz, or greater than 1 MHz. This allows processing speeds of several m / s, e.g., 20 m / s - 50 m / s, to be achieved.

[0052] As previously indicated, the invention allows for a new manufacturing process which is Figure 5 The process for manufacturing a glass pane 1, as described in its layered structure, is outlined. Figure 2The process, as outlined, initially involves the step of obtaining a first curved glass layer 2, wherein the first glass layer 2 has at least a section of a functional coating 5. The glass layer 2 is inserted into the holder 10 and fixed so that the coating 5 is closer to the laser 11. Now, the functional coating 5 on the first glass layer 2 is structured by means of laser ablation 300.

[0053] This avoids a possible reaction during bending.

[0054] In one embodiment of the invention, the functional coating 5 is applied after the glass layer 2 has been bent. This means that the method now makes it possible to bend the glass layer first and only then apply the structuring. Thus, the step of applying functional coatings 5 ​​can also be shifted to a point in time after bending. Therefore, the application of a protective layer before bending and the removal of the protective layer after bending can be omitted.

[0055] In a further embodiment of the invention, the structuring step involves the spatial displacement of a laser 11 relative to the functional coating 5. This enables cost-effective manufacturing.

[0056] According to a further embodiment of the invention, the inventive method can further comprise the step of obtaining 200 a second glass layer 3, wherein the first glass layer 2 and the second glass layer 3 are bent accordingly, the step of introducing 400 a combination film 4 between the functional coating 5, which is located on the first glass layer 2, and the second glass layer 3, as well as the step of thermally joining 500 the glass layers 2 and 3 by means of the combination film 4.

[0057] Typically, the thermal joining step 500 is carried out at a temperature typically below 140°C, i.e. at least at a temperature lower than the bending temperature, so that no reactions of a functional coating 5 are to be expected.

[0058] That is, the process can also be used to manufacture laminated glass panes 1 - as in Figure 2based on the second glass layer 3 shown with dashed lines and the combination film 4 - can be used. Reference symbol list

[0059] 1 Glass pane 2 First curved glass layer 3 Second curved glass layer 4 Combination film 5 Functional coating 10 Holder 11 Laser 12 Steering unit 13 Holding device 20 Device d Distance between laser 11 and functional coating 5 Procedural steps

[0060] 100 Obtaining a first curved glass layer 2 200 Obtaining a second curved glass layer 3 300 Structuring the functional coating 5 400 Applying a combination film 4 500 Thermally bonding the glass layers 2,3

Claims

1. Device (20) for producing a patterned functional coating (5) on a first curved glass layer (2) for a glass pane (1), wherein the functional coating (5) has an electrically conductive coating and / or a low-E coating, comprising • a support (10) for holding the first curved glass layer (2), • at least one laser (11), and • a guidance unit (12), provided for guiding the beam of the laser (11) over the functional coating (5) such that parts of the functional coating (5) are removed in order to pattern the functional coating (5) in the surface, characterized in that the guidance unit (12) is provided in the form of a tilting mirror having degrees of freedom and / or a carriage movable in one, two, and / or three dimensions, and the support is implemented such that a distance (d) between the laser (11) and the functional coating (5) is approx. 0.5 m up to 2 m, when the first curved glass layer (2) is held in the support.

2. Device (20) for producing according to claim 1, characterized in that the guidance unit (12) is provided to displace the laser (11) relative to the surface of the functional coating (5).

3. Device (20) for producing according to one of claims 1 or 2, characterized in that the laser (11) provides pulsed laser radiation with power of 100 watts or more.

4. Device (20) for producing according to one of claims 1 through 3, characterized in that the light of the laser (11) has a wavelength of 355 nm, 532 nm, or 1064 nm.

5. Device (20) for producing according to one of claims 1 through 4, characterized in that the laser (11) provides pulsed laser radiation with a period of a few nanoseconds to a few picoseconds.

6. Device (20) for producing according to one of claims 1 through 5, characterized in that the laser (11) is a CO2 laser.

7. Method for producing a glass pane (1), comprising the steps: • Obtaining (100) a first curved glass layer (2), wherein the first glass layer (2) has, at least in sections, a functional coating (5), wherein the functional coating (5) comprises an electrically conductive coating and / or a low-E coating, and wherein the functional coating (5) is applied after the bending of the glass layer (2), • Patterning (300) the functional coating (5) on the first glass layer (2) by laser ablation, wherein ∘ the laser (11) provides pulsed laser radiation with power of 100 watts or more, and / or ∘ the light of the laser (11) has a wavelength of 355 nm, 532 nm, or 1064 m, and / or ∘ the laser (11) provides pulsed laser radiation with a period of a few nanoseconds to a few picoseconds, characterized in that a beam of the laser (11) is guided by means of a guidance unit (12) over the functional coating (5), and that the guidance unit (12) is provided in the form of a tilting mirror having degrees of freedom and / or a carriage movable in one, two, or three dimensions, wherein the distance (d) between the laser (11) and the functional coating (5) is approx. 0.5 m up to 2 m.

8. Method according to one of claims [sic: claim] 7, wherein the patterning step comprises the spatial displacement of a laser (11) relative to the functional layer (5).

9. Method according to one of claims 7 or 8, further comprising the steps • Obtaining (200) a second curved glass layer (3), wherein the first glass pane [sic: glass layer] (2) and the second glass layer (3) are correspondingly bent, • Inserting (400) a combination film (4) between the functional coating (5) on the first glass layer (2) and the second glass layer (3), • Thermal bonding (500) of the glass layers (2,3) by means of the combination film (4).