Coating method for large-area glass substrates

Abstract

Provided is a method for coating large area glass substrates, comprising the steps of: a) applying a water-soluble layer to at least one first predetermined area of ​​the surface of the glass substrate, leaving at least one second predetermined area of ​​the surface of the glass substrate free of the water-soluble layer; b) coating the surface of the glass substrate with at least one water-insoluble layer; and c) removing the water-soluble layer, wherein steps a) to c) are performed multiple times in succession.

Description

[Technical Field]

[0001] This disclosure relates to an iterative method for coating large-area glass substrates.

[0002] The so-called lift-off method (photolithography) using photoresist is known in electronics. In these methods, the photoresist is coated onto a substrate, exposed to light at the locations defined by a mask, and then developed. The unexposed areas of the photoresist are then removed using a corresponding solvent. In a further step, the substrate or photoresist is coated with a material (or etching can be used to remove the material). In the final step, the photoresist is removed from the substrate using a corresponding solvent, and therefore the material layer coated on the photoresist is also removed. Thus, the substrate remains with the material layer at the locations where the photoresist was not present during coating.

[0003] Due to the complex work processes involved in known methods (coating with photoresist, exposure, and development), these methods are not suitable for large-area coatings.

[0004] Alternative masking techniques are being applied in the automotive industry. Here, the masking layer is applied by screen printing. In a further step, prior to the sputtering process, the masking layer is dried in an oven, followed by the application of a low-emissivity (low-e) layer. After coating, the masking layer is dissolved for a period of time and then washed away along with the layer above it.

[0005] The object of this disclosure is to provide a method that enables efficient coating of large-area glass substrates in particular, compared to known methods.

[0006] This objective is achieved by the features of the independent claim. The dependent claim relates to an advantageous embodiment.

[0007] According to one aspect of the present disclosure, a method for coating a large-area glass substrate is provided, comprising: a) a step of applying a water-soluble layer to at least one first predetermined region on the surface of the glass substrate, wherein at least one second predetermined region on the surface of the glass substrate is left free from the water-soluble layer; b) a step of coating the surface of the glass substrate with at least one water-non-water-soluble layer; and c) a step of removing the water-soluble layer, wherein steps a) to c) are performed multiple times in succession.

[0008] The above method in the automotive field allows only structured coatings to be realized. In other words, a portion of the substrate is sputtered (or ion beam) coated after step c), while a masked portion remains uncoated. If the method is repeated according to one aspect of this disclosure (iterative method), multiple different sputtered layers (depending on the number of iterations) can be placed on the substrate (e.g., red, green, and blue filters (RGB) after three iterations).

[0009] Different embodiments may preferably implement the following features:

[0010] The water-soluble layer is preferably not a photoresist.

[0011] The water-soluble layer is preferably water-soluble. Alternatively, the water-soluble layer can be removed using a further solvent (e.g., alcohol). In other words, the water-soluble layer does not need to be limited to being water-soluble.

[0012] The glass substrate is preferably 1 m 2 ~60m 2 Preferably 19m 2 ~60m 2 , particularly preferably 19m 2 ~39m 2 It has an area of ​​.

[0013] The size of the so-called measuring tape (standard dimensions in the coating industry) for glass substrates is preferably 3.21m × 6.00m. Alternatively, the glass substrate may be 3.21m × 12m or even 3.21m × 18m in size. The lower dimensions can be limited by the spacing of the conveyor rollers. The typical minimum dimensions of a glass substrate are 1m × 1m.

[0014] The coating process is preferably performed immediately after the process of applying the water-soluble layer.

[0015] In other words, preferably, further process steps such as exposure and development are not performed after the application of the water-soluble layer and before the coating. This also eliminates the need for the use and disposal of photoresist and developer chemicals. However, certain drying steps may be performed after the application of the water-soluble layer and before the coating to dry the water-soluble layer. In other words, preferably, at least the exposure and / or development steps are not performed after the application of the water-soluble layer and before the coating.

[0016] The water-soluble layer is preferably applied by printing, particularly by screen printing, offset printing, web printing, or digital printing.

[0017] The water-soluble layer preferably has a higher surface tension compared to the surface energy of the glass substrate in order to produce hydrophobic glass substrate properties. For example, the surface energy of purified soda glass is approximately 47 mJ / m². 2 This is within the range. Therefore, the surface tension of the water-soluble coating is preferably >60 mJ / m 2 This may be within the range of [specified range]. This disclosure is not limited to this preferred example, and other ratios of surface tension are also possible.

[0018] Furthermore, surface tension can be optimized over a wide range using corresponding additives.

[0019] The water-soluble layer preferably contains a water-soluble ink, preferably a water-soluble ink in which a colorant is dissolved, and particularly preferably a pigment ink dispersed in water.

[0020] Preferably, the method has a step of reducing the surface energy of the surface of the glass substrate before step a), and the step of reducing the surface energy of the surface of the glass substrate preferably includes plasma polymerization of hexamethyldisiloxane.

[0021] The coating on the surface of the glass substrate preferably includes a directional coating method, preferably sputtering or ion beam coating.

[0022] The removal of the water-soluble layer preferably includes the removal of the water-soluble layer and the water-insoluble layer located on the water-soluble layer.

[0023] The removal of the water-soluble layer is preferably carried out using a solvent, preferably a liquid containing water.

[0024] The water-insoluble layer also preferably locates on at least a part of the water-soluble layer after coating and mixes with the solvent when the water-soluble layer is removed using the solvent.

[0025] The step of removing the water-soluble layer preferably includes a step of filtering the water-insoluble layer in the solvent.

[0026] The removal of the water-soluble layer is preferably supported by a mechanical method, preferably brushing.

[0027] Preferably, the method has a step of cleaning the surface of the glass substrate before applying the water-soluble layer.

[0028] In subsequent executions of steps a) to c), the first and second predetermined regions are preferably at least partially different from the previous execution of steps a) to c) in order to arrange a plurality of structures, preferably optical filters, adjacent to each other.

Brief Description of the Drawings

[0029] The above-described embodiments will be explained in more detail below with reference to exemplary embodiments and drawings. The following are shown: [Figure 1a-d] This is a schematic diagram of the process steps of a method according to one embodiment of the present disclosure. [Figure 1e-h] This is a schematic diagram of a further step of the method according to one embodiment of the present disclosure. [Figure 2] This is a flowchart according to an embodiment of the disclosure.

[0030] Figures 1a) to 1d) show the steps of a method according to one embodiment of the present disclosure. As seen in Figure 1a), in the first step, the printing ink 20 is applied to a predetermined position on the glass substrate 10. According to Figure 1b), the material 30 is applied. Thus, the material 30 is placed on the glass substrate 10 (in an exposed position) and on the printing ink 20. In a further step according to Figure 1c), the printing ink 20 is separated from the glass substrate 10 with water or another solvent. At this time, the material 30 located on the printing ink 20 is also peeled off. The material 30 located on the glass substrate 10 remains on the glass substrate 10 and thus forms a desired structure on the glass substrate 10, as shown in Figure 1d).

[0031] Further details and examples of the above-mentioned process in Figures 1a) to d) are described below.

[0032] According to the present disclosure, the structured optical layer 30 is manufactured on a large area (glass substrate 10) by, for example, replacing a microlithography process with direct printing of a water-soluble ink onto a large substrate 10 (e.g., 3.21 m × 6 m). After cleaning the glass substrate 10, a water-soluble layer 20 is printed on the glass substrate 10 over areas where the optical layer 30 is not desired (e.g., by screen printing, digital printing, etc.). After the masking process, the optical layer 30 is provided on the printed substrate 10 (e.g., by sputtering, evaporation, etc.). After coating, the substrate 10 is cleaned again, whereby the masking layer 20 under the optical coating 30 dissolves in water and the optical layer 30 located thereon is likewise removed. Here, the optical layer 30 is located on the substrate 10 over areas that were not previously printed. There is no optical coating 30 on the previously masked areas on the substrate 10.

[0033] In contrast to methods in electronics engineering, this method is carried out with a significantly large substrate size (square meters) and requires different structural accuracies (about 100 μm). Further, in the method of the present invention, masking is directly printed and there is no need to manufacture it by a complex method of coating with a photoresist, exposure, and development.

[0034] To improve the separation of the ink 20 after coating, the following advantageous embodiments can be used with respect to the masking ink, the substrate material, and the coating method.

[0035] To achieve an edge with as steep a gradient as possible, the printed ink 20 can be hydrophobic rather than wetting the glass substrate 10. Physically, this means that the printed ink 20 has a high surface tension. As a result of this property, a high contact angle is achieved during printing, and thus a steep-gradient “masking edge” that is not covered by the coating material 30 during subsequent coating is achieved. In addition, the masking ink 20 can be water-soluble and, during the coating process, especially in a vacuum coating method (pressure < 10 -3This property must not be lost due to the action of plasma (mbar), UV irradiation, and temperatures of 50°C to 80°C. Particularly suitable is a pigment ink dispersed in water, which leaves a chalky layer after the evaporation of water, and this chalky layer can be separated with water after coating. To achieve sufficient opacity, it is advantageous to increase the pigment or filler content of the printing ink 20 until a sufficient degree of coating of the substrate 10 by the ink 20 is achieved. Alternatively, a water-soluble ink having a dissolved colorant with the same properties (opacity, surface tension) can also be considered.

[0036] Alternatively, in order to achieve the high contact angle mentioned, the surface energy of the surface to be coated can be reduced by a suitable coating (for example, by plasma polymerization of hexamethyldisiloxane (HMDSO)).

[0037] To avoid situations where the edges formed by the steep slope of the masking are not coated, a "highly directional" coating method, preferably sputtering or ion beam coating, is suitable. Isotropic coating methods such as atomic layer deposition (ALD) or plasma-enhanced chemical vapor deposition (PECVD) are not very suitable.

[0038] It is preferable that the process for separating the printing ink 20 (Figure 1c) together with the coating 30 located on top of it also be subject to similarly high requirements. On the one hand, the printing ink 30 should be completely dissolved so that the coating 20 located on top of it is completely separated from the substrate 10. If this is done using mechanical support (e.g., brushing), the ink 20 should be removed without mechanically damaging the underlying substrate 10 and the coating 30 remaining on the substrate 10 (scratching, breakout at the edges of the coating structure), or even without separating them.

[0039] The separation process steps may include, for example, the following: 1. A solvent (preferably water) is sprayed or injected onto the substrate 10. To accelerate the process, the solvent may be warm (e.g., 30°C). 2. The solvent remains on the substrate 10 until the printing ink 30 beneath the coating 20 is dissolved as much as possible. 3. The solvent, having partially dissolved printing ink 30 and the coating 20 above it, is rinsed with a further solvent, and any residue is completely removed with a soft roller brush (with long, fine bristles).

[0040] After the successful removal of the printing ink 20 from the substrate 10, the printing ink is dissolved in the solvent. In addition, the solvent portion of the coating 30 contains particles separated by the dissolution of the printing ink 20 from the substrate 10. These very small particles (~approximately 10 μm to 100 μm) should not reach the substrate 10 so as not to deposit or dry (adhere) on the substrate 10. To avoid high concentrations of these coating particles in the solvent, they can preferably be continuously filtered out of the solvent. In addition to water-soluble substances, alternative solvents (e.g., alcohol) can also be used for the lift-off step (Figure 1c).

[0041] As shown in the exemplary embodiment in Figure 1, in the first step (Figure 1a), the glass substrate 10 is partially printed (masked) with a water-soluble substance 20. In the second step (Figure 1b), the partially printed substrate 10 is coated with a layer 30 (e.g., an interference layer system). This interference layer system 30 can perform various functions (low-e, AR, dichroic filter, or mirror, etc.). After coating (Figure 1c), the printed substance 30 is dissolved in a cleaning process and removed along with the interference layer system deposited thereon (lift-off). The substrate partially coated with the interference layer system remains (Figure 1d).

[0042] Figures 1e) to 1h) show further steps of a method according to one embodiment of the present disclosure. The steps of Figures 1e) to 1h) substantially correspond to a repetition of the steps of Figures 1a) to 1d), but preferably the areas to which the printing ink 20 and / or coating material 31 are applied according to Figures 1e) to 1h) are at least partially different from the areas or material 30 of the steps of Figures 1a) to 1d).

[0043] As shown in Figure 1e), the printing ink 20 is applied to a predetermined location on the glass substrate 10 (here, the location of the first interference layer system 30) in a subsequent step following the process in Figure 1d). According to Figure 1f), a material 31, preferably a different material 31 from the material 30 from the steps in Figures 1a) to d), is applied. Thus, the material 31 is placed on the glass substrate 10 (in exposed locations, e.g., locations where material 30 is not placed) and on the printing ink 20. In a further step according to Figure 1g), the printing ink 20 is separated from the glass substrate 10 with water or another solvent. At this time, the material 31 located on the printing ink 20 is also peeled off. The material 31 located on the glass substrate 10 remains on the glass substrate 10 and thus forms a desired structure on the glass substrate 10, as shown in Figure 1h). Preferably, the region having material 31 is adjacent to the region having material 30. However, material 31 may be in a region separate from material 30, that is, material 31 may not be adjacent to material 30 (or may only be partially adjacent).

[0044] Referring to Figures 1a) to d), the steps and conditions listed above are applied equally to the steps in Figures 1e) to h), and are not repeated at this point.

[0045] Figure 2 shows a flowchart of a method for coating a large-area glass substrate according to an embodiment of the present disclosure, comprising steps S101 to S103. The method according to Figure 2 comprises the following steps.

[0046] S101: A water-soluble layer is applied to at least one first predetermined region on the surface of a glass substrate, while at least one second predetermined region on the surface of the glass substrate remains free of the water-soluble layer.

[0047] S102: The surface of the glass substrate is coated with at least one water-insoluble layer.

[0048] S103: Remove the water-soluble layer.

[0049] Steps a) to c) are preferably performed multiple times in succession.

[0050] In one embodiment, the glass substrate is 1 m 2 ~60m 2 Preferably 19m 2 ~60m 2 , particularly preferably 19m 2 ~39m 2 It has an area of ​​.

[0051] In one embodiment, the coating step is performed immediately after the step of applying the water-soluble layer.

[0052] In one embodiment, the water-soluble layer is applied by a printing method, particularly by screen printing, offset printing, web printing, or digital printing.

[0053] In one embodiment, the water-soluble layer has a higher surface tension compared to the surface energy of the glass substrate so that hydrophobic glass substrate properties are generated.

[0054] In one embodiment, the water-soluble layer contains a water-soluble ink, preferably a water-soluble ink having a dissolved colorant, and more preferably a pigment ink dispersed in water.

[0055] In one embodiment, the method includes a step of reducing the surface energy of the glass substrate surface before step a), and the step of reducing the surface energy of the glass substrate surface preferably includes plasma polymerization of hexamethyldisiloxane.

[0056] In one embodiment, coating the surface of a glass substrate includes directional coating methods, preferably sputtering or ion beam coating.

[0057] In one embodiment, the removal of the water-soluble layer includes the removal of the water-soluble layer and the non-water-soluble layer located on the water-soluble layer.

[0058] In one embodiment, the removal of the water-soluble layer is performed using a solvent, preferably a water-containing liquid.

[0059] In one embodiment, the non-water-soluble layer is also located on top of at least a portion of the water-soluble layer after coating and mixes with the solvent when the water-soluble layer is removed using the solvent.

[0060] In one embodiment, the step of removing the water-soluble layer includes the step of filtering the water-insoluble layer in the solvent.

[0061] In one embodiment, the removal of the water-soluble layer is supported by a mechanical method, preferably brushing.

[0062] In one embodiment, the method includes a step of cleaning the surface of the glass substrate before applying the water-soluble layer.

[0063] In one embodiment, in order to arrange multiple structures, preferably optical filters, adjacent to each other, the first and second predetermined regions in subsequent executions of steps a) to c) are at least partially different from the preceding executions of steps a) to c).

[0064] This disclosure is illustrated and described in detail by the drawings and related description, but these drawings and this detailed description should be understood as illustrative and exemplary and not limiting to this disclosure. It will be understood that those skilled in the art can make changes and modifications without departing from the following claims. In particular, this disclosure also includes embodiments having any combination of the features mentioned or shown above with respect to various aspects and / or embodiments.

[0065] This disclosure also includes any individual features of the drawings if they are shown in relation to other features and / or if not described above.

[0066] Furthermore, “comprise” and its derivatives do not exclude other elements or steps. Similarly, the indefinite articles, “a” or “an” and their derivatives do not exclude plurals. The functions of multiple features listed in the claims may be fulfilled by a single unit. Also, terms such as “substantially,” “around,” and “approximately” are used in conjunction with characteristics or values, in particular to define the characteristics or values ​​precisely. None of the reference numerals in the claims should be understood as limiting the claims.

Claims

1. A method for coating a large-area glass substrate (10), a) A step of applying a water-soluble layer (20) to at least one first predetermined region on the surface of a glass substrate (10), wherein at least one second predetermined region on the surface of the glass substrate (10) is left without the water-soluble layer (20), b) A step of coating the surface of the glass substrate (10) with at least one water-insoluble layer (30), c) A step of removing the water-soluble layer (20), Includes, Steps a) to c) are performed multiple times in succession. The method is characterized in that the coating of the surface of the glass substrate (10) includes a directional coating method.

2. The glass substrate (10) is 1 m ２ ~60m ２ The method according to claim 1, having the area of ​​the above.

3. The method according to claim 1 or 2, wherein the coating step is performed immediately after the step of applying the water-soluble layer (20).

4. The method according to claim 1, wherein the coating of the water-soluble layer (20) is carried out by a printing method, particularly by screen printing, offset printing, web printing, or digital printing.

5. The method according to claim 1, wherein the water-soluble layer (20) has a surface tension higher than the surface energy of the glass substrate so that hydrophobic glass substrate properties are obtained.

6. The method according to claim 1, wherein the water-soluble layer (20) contains a water-soluble ink.

7. The method according to claim 1, further comprising the step of reducing the surface energy of the surface of the glass substrate (10) before step a).

8. The method according to claim 1, wherein the removal of the water-soluble layer (20) includes the removal of the water-soluble layer (20) and the non-water-soluble layer (30) located on the water-soluble layer (20).

9. The method according to claim 1, wherein the removal of the water-soluble layer (20) is carried out using a solvent.

10. The method according to claim 9, wherein the non-water-soluble layer (30) is also located in at least a portion of the water-soluble layer (20) after coating, and mixes with the solvent when the water-soluble layer (20) is removed using the solvent, and the step of removing the water-soluble layer (20) includes filtering the non-water-soluble layer (30) in the solvent.

11. The method according to claim 1, wherein the removal of the water-soluble layer (20) is supported by a mechanical method.

12. The method according to claim 1, further comprising the step of cleaning the surface of the glass substrate (10) before applying the water-soluble layer (20).

13. The method according to claim 1, wherein, in order to arrange multiple structures adjacent to one another, the first and second predetermined regions in subsequent executions of steps a) to c) are at least partially different from those in preceding executions of steps a) to c).

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