Process for manufacturing a sheet of glass intended to constitute a glass plate with patterns observable to the naked eye under lighting

Abstract

------ Method for manufacturing a sheet of glass intended to constitute a glass plate with patterns observable to the naked eye under illumination The invention relates to a method for manufacturing a sheet of glass 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.It comprises the following successive steps: on one side of the glass sheet to be provided with the pattern(s), a surface etching paste of P2O5-Na2O is deposited by liquid means at the location(s) corresponding to the desired pattern(s); the resulting glass sheet is subjected to a heat treatment to carry out the etching of the surface on which the paste deposit has been made, creating micro-defects on the surface of the glass sheet at the locations where the paste has been deposited; the side of the glass sheet thus treated is washed. Figure to be published with the abstract: Figure 4.

Description

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

[0001] The present invention relates to a method for manufacturing a glass sheet 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).

[0002] By "patterns not detectable to the naked eye" is meant that these patterns are invisible to the naked eye, but may become detectable only for grazing lighting and observation angles.

[0003] 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.

[0004] Currently, in order to be able to form a pattern in the glass, different approaches can be used such as: • the screen printing of a white or translucent “etch” enamel; • the deposition of an organic light-extracting ink.

[0005] 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.

[0006] The deposit of an organic ink, if it does not present mechanical embrittlement, presents 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 injection of light.

[0007] The present invention seeks to overcome these problems of the state of the 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 which enters through its edge.

[0008] This effect is obtained by depositing a specific etching agent on the surface of the glass according to the desired decoration. During heat treatment, this etching agent will react with the glass, modifying its surface appearance. Localized micro-defects are created on the surface of the glass and will subsequently allow the extraction of light.

[0009] 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.

[0010] The glasses obtained can be used for automotive and building glazing.

[0011] The present invention therefore firstly relates to a method for manufacturing a sheet of glass 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 by its edge,

[0012] characterized by the fact that it comprises the following successive steps: • on one side of the glass sheet to be provided with the pattern(s), a surface etching paste of P2O5-Na2O 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.

[0013] The glass sheet may have a thickness of 0.7 - 10 mm.

[0014] According to 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; - the attack paste is applied by screen printing or digital printing; - we apply the attack paste in all sorts of patterns, patterns under form of strips or discs which may be indicated by way of example only; - before heat treatment, the paste is dried using an infrared dryer at a temperature of 130°C - 160°C for 2-5 minutes; - the heat treatment is carried out using an industrial glass furnace at a temperature of 600°C - 700°C for 30 - 600 seconds; - washing is carried out with water using a cloth or in an industrial washing machine.

[0015] 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.

[0016] 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 process as defined above, the surface(s) comprising the micro-defects being arranged internally or externally, and that the resulting glass plate is equipped with a device for injecting light into said glass sheet.

[0017] The device for injecting light into a glass sheet 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 glass sheet to inject light into the edge thereof.

[0018] The device for injecting light into a glass sheet 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 glass sheet.

[0019] The following Examples illustrate the present invention without, however, limiting its scope. Example 1

[0020] A P2O5-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 Planiclear® brand. The paste was deposited at a thickness of 21 μm.

[0021] The pattern formed is a plurality of discs formed on the surface of the glass as shown in [Fig.l].

[0022] The glass plate is then dried at a temperature of 150°C using an infrared dryer for 2 minutes.

[0023] The glass plate is then subjected to cooking at 660°C for 40 seconds in an industrial oven.

[0024] The glass plate is then cleaned with water and a cloth. The pattern formed is then not detectable as can be seen in [Fig.2].

[0025] 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 [Fig.3].

[0026] A measurement carried out by a LUMICAM camera shows that a light extraction of up to 4 cd / m2 is obtained ([Fig.4]). Example 2

[0027] The paste was deposited as in Example 1 by screen printing with the four following thicknesses:

[0028] 1:17.8 pm

[0029] 2:28 pm

[0030] 3:38.7 pm

[0031] 4:48.9 pm

[0032] In order to form four neighboring strips on the same plate. The plate is then treated as in Example 1.

[0033] [Fig.5] shows the light extraction from each of the bands 1 to 4 after arrangement of an LED bar at the edge.

[0034] As can be seen in [Fig.5], the thinner the deposit thickness of the paste, the better the light extraction. Example 3

[0035] The procedure was 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 is then cleaned with water and a cloth.

[0036] This glass plate was then laminated with a Venus grey type tinted glass with 10% light transmission.

[0037] [Fig.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).

[0038] A prism is placed between the PLC glass plate and the RK11 layer facing a skylight formed in the Solargard PET layer.

[0039] The introduction of this prism makes it possible to inject light through the surface of the laminated glass, the prism then making it possible to redirect the light towards the edge of the laminated glass through the skylight.

[0040] [Fig.7] shows the laminated glasses obtained without light injection through the prism and [Fig.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.

[0041] As can be seen, the diffusion of light is very clear in the case where the pattern is on face 4.

[0042] In the case where the pattern is present on face 3, the light diffusion 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 the glass and therefore, during lamination, the effect of the texturing of the glass (on the light extraction efficiency) is attenuated.

[0043] [Fig.9] shows the luminance curves obtained for face 3 and [Fig. 10] that for face 4.

[0044] It can be seen that an extraction of the order of 0.6 cd / m2 is obtained on the pattern on face 3 and that an extraction of the order of 2 cd / m2 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 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 face of the glass sheet to be provided with the pattern(s), a surface etching paste of P2O5-Na2O 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 carry out the etching of the surface on which the paste has been deposited, creating micro-defects on the surface of the glass sheet at the locations where the paste has been 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 attack paste is deposited 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 of manufacturing a simple glass plate comprising at least 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 micro-defects 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.

Images