Method for manufacturing a glass sheet intended to form a glass plate having patterns visible to the naked eye under lighting

Abstract

The invention relates to a method for manufacturing a glass sheet that is intended to form a single glass plate or that is intended to form part of a laminated glass plate, and which comprises at least one pattern that is invisible to the naked eye but becomes illuminated when the glass plate is lit from its edge face. The method comprises the following successive steps: depositing, in liquid form, a P2O5-Na2O surface-etching paste on one face of the glass sheet, at the one or more locations corresponding to the desired one or more patterns; subjecting the resulting glass sheet to a heat treatment in order to etch the surface on which the paste was deposited, thereby creating micro-defects on the surface of the glass sheet at the paste deposition sites; and washing the treated face of the glass sheet.

Description

[0001] Description

[0002] Title of the invention: Method for manufacturing a sheet of glass intended to constitute a glass plate with patterns observable to the naked eye under lighting

[0003] The present invention relates to a method for manufacturing a sheet of glass which is intended to constitute a simple glass or intended to be used in the constitution of a laminated glass, and which comprises at least one pattern which is not detectable to the naked eye but which lights up when light penetrates into the glass plate, in particular through its edge, and exits through the pattern(s).

[0004] By "patterns not detectable to the naked eye" we mean that these patterns are invisible to the naked eye, but may become detectable only at grazing lighting and observation angles.

[0005] The present invention relates to the field of light extraction from a system composed at least of a glass and making it possible to form, under illumination, patterns observable to the naked eye.

[0006] Currently, in order to be able to form a pattern in the glass, we can use different approaches such as:

[0007] - the screen printing of a white or translucent “etch” enamel;

[0008] - the deposition of an organic light-extracting ink.

[0009] The enamel deposit has the disadvantage of mechanically weakening the glass. The pattern formed by the deposit is also visible to the naked eye without injecting light.

[0010] The deposit of an organic ink, if it does not present mechanical embrittlement, has a low resistance to ultraviolet rays, the initially white pattern being able to yellow over time. Also in this case, the pattern formed by the deposit is visible to the naked eye without light injection.

[0011] The present invention seeks to overcome these problems of the prior art while making it possible to obtain a glass whose pattern is not detectable to the naked eye and which only appears by light extraction when the glass is illuminated by light entering through its edge.

[0012] This effect is achieved by depositing a specific etching agent on the surface of the glass depending on the desired decoration. During heat treatment, this etching agent will react with the glass, changing its surface appearance. Localized micro-defects are created on the surface of the glass and will subsequently allow the extraction of light.

[0013] The etching agent is then dissolved in hot water in a washing step. After this washing, the decoration is invisible to the naked eye and allows light to be extracted when light enters the glass through its edge.

[0014] The glasses obtained can be used for automotive and building glazing. The present invention therefore firstly relates to a method for manufacturing a glass sheet which is intended to constitute a simple glass plate or which is intended to be used in the constitution of a laminated glass plate, and which comprises at least one pattern which is invisible to the naked eye but which lights up when the glass plate is illuminated from its edge, characterized in that it comprises the following successive steps:

[0015] - on one side of the glass sheet to be provided with the pattern(s), a P2Os-Na2O surface etching paste is deposited by liquid means at the location(s) corresponding to the desired pattern(s);

[0016] - the resulting glass sheet is subjected to a heat treatment to attack the surface on which the paste was deposited, creating micro-defects on the surface of the glass sheet at the locations where the paste was deposited;

[0017] - the face of the glass sheet thus treated is washed.

[0018] The glass sheet can have a thickness of 0.7 -

[0019] 10 mm.

[0020] In accordance with particular embodiments of the method according to the invention: the attack paste is deposited in a thickness of 1 μm - 100 μm, preferably 10 μm to 50 μm;

[0021] - the attack paste is applied by screen printing or digital printing;

[0022] - the attack paste is deposited in all sorts of patterns, patterns in the form of bands or discs being indicated as examples only;

[0023] - before heat treatment, the paste is dried using an infrared dryer at a temperature of

[0024] 130°C - 160°C for 2 - 5 minutes;

[0025] - the heat treatment is carried out using an industrial glass furnace at a temperature of 600°C - 700°C for 30 - 600 seconds;

[0026] - washing is carried out with water using a cloth or in an industrial washing machine.

[0027] The present invention also relates to a method for manufacturing a simple glass plate comprising at least one pattern which is not detectable to the naked eye but which lights up when light enters the glass plate, in particular through its edge, and exits through the pattern(s), characterized in that a glass sheet manufactured by the method as defined above is equipped with a device for injecting light into said glass sheet.The present invention also relates to a method for manufacturing a laminated glass plate comprising at least one pattern which is not detectable to the naked eye but which lights up when light enters the glass plate, in particular through its edge, and exits through the pattern(s), characterized in that a laminated glass plate is manufactured by placing an interlayer lamination sheet between two glass sheets, at least one of which has been manufactured by the method as defined above, the surface(s) comprising the microdefects being arranged internally or externally, and that the resulting glass plate is equipped with a device for injecting light into said glass sheet.

[0028] The device for injecting light into a sheet of glass may consist of one or more strips of light-emitting diodes capable of being connected to a source of electrical energy, each strip of diodes being mounted along an edge of the sheet of glass to inject light into the edge thereof.

[0029] The device for injecting light into a sheet of glass may consist of a light source which is capable of illuminating one of the faces thereof and with which is advantageously associated a prism capable of redirecting the light towards the interior of the sheet of glass.

[0030] The following Examples illustrate the present invention without, however, limiting its scope. Example 1

[0031] A P2Os-Na2O paste marketed by Ferro under the name CRW 10 4590 AL (=TDF9283AAL) was deposited by screen printing on a standard 2.1 mm clear glass plate and marketed under the brand name Planiclear®. The paste was deposited at a thickness of 21 μm.

[0032] The pattern formed is a plurality of discs formed on the surface of the glass as shown in Figure 1.

[0033] The glass plate is then dried at a temperature of 150°C using an infrared dryer for 2 minutes.

[0034] The glass plate is then subjected to cooking at 660°C for 40 seconds in an industrial oven.

[0035] The glass plate is then cleaned with water and a cloth. The pattern formed is then not detectable as can be seen in Figure 2.

[0036] An LED bar is then placed at the edge of the glass plate. The pattern that was not detectable lights up and appears very clearly as can be seen in Figure 3. A measurement made by a LUMICAM camera shows that light extraction up to 4 cd / m 2 is obtained (Figure 4).

[0037] Example 2

[0038] As in Example 1, the paste was deposited by screen printing with the following four thicknesses:

[0039] 1:17, 8 pm 2:28 pm

[0040] 3:38.7 pm

[0041] 4:48, 9 pm

[0042] In order to form four neighboring strips on the same plate. The plate is then treated as in Example 1.

[0043] Figure 5 shows the light extraction from each of strips 1 to 4 after arranging an LED bar at the edge.

[0044] As can be seen in Figure 5, the thinner the paste deposit thickness, the better the light extraction.

[0045] Example 3

[0046] The procedure was the same as in Example 1, except that a Northglass® brand oven was used at a set temperature of 660°C and a residence time of 400 s in order to obtain a PLC glass plate. The glass plate was then cleaned with water and wiped with a cloth. This glass plate was then laminated with Venus grey tinted glass with 10% light transmission.

[0047] Figure 6 shows a schematic representation of the laminated glass obtained in the case where the pattern is placed on the outer surface of the laminated glass (face 4) or on the surface of the glass plate facing the RK11 layer (face 3).

[0048] A prism is placed between the PLC glass plate and the RK11 layer facing a skylight formed in the Solargard PET layer.

[0049] The introduction of this prism allows light to be injected through the surface of the laminated glass, the prism then allowing the light to be redirected towards the edge of the laminated glass through the skylight.

[0050] Figure 7 shows the laminated glasses obtained without light injection through the prism and Figure 8 shows the laminated glasses obtained with light injection through the prism. The laminated glass with the pattern on the outer surface is on the right in these two figures.

[0051] As we can see, the diffusion of light is very clear in the case where the pattern is on face 4.

[0052] In the case where the pattern is present on face 3, the light scattering is weaker. This is probably due to an inhibition effect of the pattern effect when the PLC glass plate is brought into contact with the RK11 sheet of poly(vinyl butyral). Indeed, the latter does not have an optical index significantly different from that of glass and therefore, during lamination, the effect of the texturing of the glass (on the light extraction efficiency) is attenuated.

[0053] Figure 9 shows the luminance curves obtained for face 3 and Figure 10 shows the luminance curves obtained for face 4.

[0054] It can be seen that an extraction of the order of 0.6 cd / m 2 is obtained on the pattern on face 3 and that an extraction of the order of 2 cd / m 2 is obtained on the pattern on face 4.

Claims

Claims

1. - Method for manufacturing a glass sheet which is intended to constitute a simple glass plate or which is intended to be used in the constitution of a laminated glass plate, and which comprises at least one pattern which is not detectable to the naked eye but which lights up when light penetrates into the glass plate, in particular through its edge, and emerges through the pattern(s), characterized in that it comprises the following successive steps: - on one side of the glass sheet to be provided with the pattern(s), a P2Os-Na2O surface etching paste is deposited by liquid means at the location or locations corresponding to the desired pattern(s); - the resulting glass sheet is subjected to a heat treatment to attack the surface on which the paste was deposited, creating micro-defects on the surface of the glass sheet at the locations where the paste was deposited; - the face of the glass sheet thus treated is washed.

2. - Method according to claim 1, characterized in that the glass sheet has a thickness of 0.7 - 10 mm.

3. - Method according to one of claims 1 and 2, characterized in that the dough is deposited attack in a thickness of 1 pm - 100 pm, preferably 10 pm to 50 pm.

4. - Method according to one of claims 1 to 3, characterized in that the attack paste is deposited by screen printing or digital printing.

5. - Method according to one of claims 1 to 4, characterized in that before the heat treatment, the paste is dried using an infrared dryer at a temperature of 130°C - 160°C for 2 - 5 minutes.

6. - Method according to one of claims 1 to 5, characterized in that the heat treatment is carried out using an industrial glass furnace at a temperature of 600°C - 700°C for 30 - 600 seconds.

7. - Method according to one of claims 1 to 6, characterized in that the washing is carried out with water using a cloth or in an industrial washing machine.

8. - Method for manufacturing a simple glass plate comprising at least one pattern which is not detectable to the naked eye but which lights up when light enters the glass plate, in particular through its edge, and exits through the pattern(s), characterized in that a glass sheet manufactured by the method as defined in one of claims 1 to 7 is equipped with a device for injecting light into said glass sheet.

9. - Method for manufacturing a laminated glass plate comprising at least one pattern which is not detectable to the naked eye but which lights up when light enters the glass plate, in particular through its edge, and exits through the pattern(s), characterized in that a laminated glass plate is manufactured by placing a lamination interlayer sheet between two glass sheets, at least one of which has been manufactured by the method as defined in one of claims 1 to 7, the surface(s) comprising the microdefects being arranged internally or externally, and that the resulting glass plate is equipped with a device for injecting light into the glass sheet(s).

10. - Method according to one of claims 8 or 9, characterized in that the device for injecting light into a sheet of glass consists of one or more strips of light-emitting diodes capable of being connected to a source of electrical energy, each strip of diodes being mounted along an edge of the sheet of glass to inject light into the edge thereof.

11. - Method according to one of claims 8 or 9, characterized in that the device for injecting light into a sheet of glass consists of a light source which is capable of illuminating one of the faces thereof and with which is advantageously associated a prism capable of redirecting the light towards the interior of the sheet of glass.

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