The present invention relates to a method of making a glazing and to a glazing for use in an automobile, in particular for use as a sheet of a laminated windscreen for an automobile.

Conventional laminated glazings for automotive windscreens comprise two plies of soda-lime- silicate glass joined by a sheet of polyvinyl butyral (PVB). Typically, each glass sheet is 2.1mm thick and the PVB sheet is typically 0.76mm thick. It is known to use thinner or thicker sheets of glass and/or sheets of PVB.

As is known in the art, a laminated automotive windscreen provides the driver of the vehicle with improved safety benefits. However, vehicle manufacturers are also addressing vehicle safety in the event of a forward collision with a pedestrian.

In the event of a collision with a pedestrian, the pedestrian may impact the vehicle windscreen thereby causing further injury to the pedestrian.

The present invention aims to provide a vehicle windscreen that is arranged to lower the risks of serious pedestrian injuries in case the vehicle collides with a pedestrian.

Accordingly, from a first aspect the present invention provides a method of making a glazing comprising the steps: (i) providing a first sheet of glass, the first sheet of glass having a first major surface and a second opposing major surface; (ii) coating at least a first region of the first major surface of the first sheet of glass with a coating, there being a first region of the second major surface of the first sheet of glass aligned with the first region of the first major surface of the first sheet of glass; (iii) processing the coating on the first region of the first major surface of the first sheet of glass to weaken the first sheet of glass between the first region of the first major surface of the first sheet of glass and the first region of the second major surface of the first sheet of glass.

It has been found that following step (iii), the processed first sheet of glass is easier to break compared to a first sheet of glass produced using the same method but without step (iii) because the first sheet of glass has been weakened beneath the coating on the first region of the first major surface of the first sheet of glass.

Preferably following step (ii), the coating has a thickness between 1pm and 100pm, more preferably between 5pm and 75pm, even more preferably between 10pm and 60pm.

Preferably during step (iii) processing the coating includes removing at least a portion of the coating on the first region of the first major surface of the first sheet of glass. Preferably during step (iii) processing the coating includes removing a portion of the coating on the first region of the first major surface of the first sheet of glass that extends through a thickness of the coating preferably to expose the first major surface of the first sheet of glass.

Preferably during step (iii) the coating on the first region of the first major surface of the first sheet of glass is processed by directing a laser towards the coating.

Preferably during step (iii) the coating on the first region of the first major surface of the first sheet of glass is processed by mechanically abrading the coating.

Preferably during step (iii) the coating on the first region of the first major surface of the first sheet of glass is processed by sandblasting the coating.

Preferably the first sheet of glass is weakened between the first region of the first major surface of the first sheet of glass and the first region of the second major surface of the first sheet of glass by the formation of at least one line of weakness in the first sheet of glass. Preferably the at least one line of weakness is a crack.

In some embodiments during step (iii) the coating on the first region of the first major surface of the first sheet of glass is processed by directing a laser towards the coating.

The laser produces a laser beam that strikes the coating. Preferably the laser beam strikes the coating before passing through the second major of the first sheet of glass.

Preferably the laser is operable at a wavelength greater than lOOnm.

Preferably the laser is operable at a wavelength less than 20pm.

Preferably the laser is an excimer laser.

Preferably the laser is a carbon dioxide laser.

Preferably the laser is a neodymiunrYAG laser or a neodymiunryttrium orthovanadate (YVCfi) laser.

Preferably the laser is operable at a wavelength between 300nm and L pm, wherein L is 0.5, or 1, or 1.5, or 2, or 3, or 4, or 5, or 6, or 7, or 8, or 9, or 10, or 11, or 15. For example, preferably the laser is operable at a wavelength between 300nm and 1.5pm.

Preferably the laser is operable at about 1064nm.

Preferably the laser is operable at about 10.6pm. Preferably the laser is focussed to a spot size having a maximum external dimension less than 1mm. If the spot is circular, the maximum external dimension is the diameter of the spot.

Preferably a laser beam is directed across the coating on the first region of the first major surface of the first sheet of glass in a line, which may be straight or curved. The line may be a continuous line.

The laser may be a continuous laser or a pulsed laser.

Preferably the laser has a power sufficient to weaken the glass beneath the coating.

Preferably the laser is directed towards the first region for sufficient time to weaken the glass beneath the coating.

In some embodiments the glazing is a laminated glazing comprising a second sheet of glass and an interlayer structure comprising at least a first sheet of adhesive interlayer material, the laminated glazing being arranged with the interlayer structure between the first sheet of glass and the second sheet of glass, the method further comprising a lamination step for laminating the first sheet of glass to the second sheet of glass by means of the interlayer structure.

Preferably step (iii) takes place before the lamination step.

Preferably during the lamination step the second major surface of the first sheet of glass faces the first sheet of adhesive interlayer material. In these embodiments, following the lamination step, the laminated glazing is arranged such that the second major surface of the first sheet of glass faces the first sheet of adhesive interlayer material.

Preferably during the lamination step the first major surface of the first sheet of glass faces the first sheet of adhesive interlayer material. In these embodiments, following the lamination step, the laminated glazing is arranged such that the first major surface of the first sheet of glass faces the first sheet of adhesive interlayer material.

Preferably the first major surface of the first sheet of glazing material is concave.

Preferably the laminated glazing is curved in at least one direction. Preferably the radius of curvature in the at least one direction is between 500mm and 20000mm, more preferably between 1000mm and 8000mm.

Preferably the first sheet of adhesive interlayer material comprises polyvinyl butyral (PVB), acoustic modified PVB, a copolymer of ethylene, such as ethylene vinyl acetate (EVA), polyvinyl chloride (PVC), ethyl methyl acrylate (EMA) copolymer, polyurethane, in particular a thermoplastic polyurethane (TPU), or a liquid curable resin such as Uvekol. Preferably the interlayer structure comprises 2, or 3, or 4, or 5, or 6, or 7, or 8, or 9, or 10, or more, sheets of adhesive interlayer material. Each sheet of adhesive interlayer material may be the same type i.e. all PVB and may all have the same thickness.

Preferably the first sheet of adhesive interlayer material has a thickness between 0.3mm and 2.3mm, more preferably between 0.3mm and 1.6mm, most preferably between 0.3 and 0.8mm.

Preferably the interlayer structure comprises at least one sheet of polyester, more preferably as least one sheet of polyethylene terephthalate (PET), and preferably the at least one sheet of polyester carries on at least one major surface thereof an optically transparent coating that reflects infrared radiation.

As is conventional in the art, surface one of a laminated glazing is an outermost surface of the laminated glazing and surface four of the laminated glazing is an inner facing surface being defined in relation to a vehicle interior in which the laminated glazing is installed.

When the glazing is a laminated glazing, preferably the first major surface of the first sheet of glass is surface three or surface four of the laminated glazing.

In some embodiments wherein during step (iii) the coating is processed by directing a laser towards the coating, preferably the coating is optically opaque at one or more wavelength in the wavelength range 380nm to 780nm. The coating is optically opaque if the transmittance at normal incidence through the coated first region of the first sheet of glass at the one or more wavelength is less than 10%, preferably less than 5%.

The laser produces a laser beam that strikes the coating. Preferably the laser beam strikes the coating before passing through the second major of the first sheet of glass.

Preferably the laser is operable at a wavelength greater than lOOnm.

Preferably the laser is operable at a wavelength less than 20pm.

Preferably the laser is an excimer laser.

Preferably the laser is a carbon dioxide laser.

Preferably the laser is a neodymium:YAG laser or a neodymium: yttrium orthovanadate (YVO4) laser.

Preferably the laser is at least one of an excimer laser, a carbon dioxide laser, a neodymium :YAG laser and a neodymiunryttrium orthovanadate (YVO4) laser.

Preferably the laser is operable at a wavelength between 300nm and L pm, wherein L is 0.5, or 1, or 1.5, or 2, or 3, or 4, or 5, or 6, or 7, or 8, or 9, or 10, or 11, or 15. For example, preferably the laser is operable at a wavelength between 300nm and 1.5pm. Preferably the laser is operable at about 1064nm.

Preferably the laser is operable at about 10.6pm.

Preferably the laser is focussed to a spot size having a maximum external dimension less than 1mm. If the spot is circular, the maximum external dimension is the diameter of the spot.

Preferably a laser beam is directed across the coating on the first region of the first major surface of the first sheet of glass in a line, which may be straight or curved. The line may be a continuous line.

The laser may be a continuous laser or a pulsed laser.

Preferably the laser has a power sufficient to weaken the glass beneath the coating.

Preferably the laser is directed towards the first region for sufficient time to weaken the glass beneath the coating.

In some embodiments the coating comprises a frit.

Preferably the frit is a type of frit used to provide an automotive glazing with an obscuration band.

Preferably during step (ii) the frit is applied to the first region of the first major surface of the first sheet of glass using a screen printing process. Screen printing processes are well known in the art.

Preferably the screen printed material has a composition comprising from about 35 to about 75 weight percent frit, from about 5 to about 40 weight percent of a pigment, from zero to about 25 weight percent of a crystal seed powder, and from about 10 to about 40 weight percent of a printing medium. More preferably, the screen printed material comprises from about 40 to about 60 weight percent frit, from about 10 to about 35 weight percent of a pigment, from zero to about 25 weight percent of a crystal seed powder, from zero to about 10 weight percent of a metal and/or a metal oxide, and from about 15 to about 40 weight of a percent printing medium.

When the frit comprises a glass frit, the frit of the screen printed material may comprise lead- containing frit and/or lead-free frit.

Preferably the frit comprises a glass frit and/or a ceramic frit.

As used herein, the term "glass frit" means pre-fused glass material which is typically produced by rapid solidification of molten material followed by grinding or milling to a desired powder size. Preferred glass frits may comprise from 0 to about 75 weight percent lead oxide, from 0 to about 75 weight percent bismuth oxide, from 0 to about 75 weight percent silica, from 0 to about 50 weight percent zinc oxide, from 0 to about 40 weight percent boron oxide, from 0 to about 15 weight percent aluminium oxide, from 0 to about 15 weight percent zirconium oxide, from 0 to about 8 weight percent titanium oxide, from 0 to about 20 weight percent phosphorous oxide, from 0 to about 15 weight percent calcium oxide, from 0 to about 10 weight percent manganese oxide, from 0 to about 7 weight percent copper oxide, from 0 to about 5 weight percent cobalt oxide, from 0 to about 15 weight percent iron oxide, from 0 to about 20 weight percent sodium oxide, from 0 to about 20 weight percent potassium oxide, from 0 to about 15 weight percent lithium oxide and from 0 to about 7 weight percent fluoride, as well as other oxides conventionally used in glass frit compositions.

The pigment of the screen printed material may comprise inorganic pigments such as spinels, zircons, rutiles, garnets, hematites, ultramarines and the like may also be used as the marking component. In addition to inorganic pigments, precursors thereof are useful in forming high quality marks. For example, a light green coloured mixture of titanium dioxide, antimony trioxide and chrome oxide, which is the precursor to Cr-Sb-Ti buff, may be used.

The crystal seed powder of the screen printed material may comprise, for example, bismuth silicate, zinc silicate and/or zinc borate.

Metal oxides include cobalt oxide, copper oxide, iron oxide and praseodymium oxide.

Suitable metal includes metal powders such as iron, copper, nickel, silver, chromium, and the like.

In some embodiments during step (iii) the coating is processed to produce a pattern therein or thereon. Preferably the pattern includes at least a void in the coating on the first region of the first major surface of the first sheet of glass. The void may extend through a thickness of the coating to the glass surface underneath or only part way through the thickness of the coating.

Preferably the pattern comprises a line, which may be straight or curved.

Preferably the pattern comprises at least one of a square, a rectangle, a triangle, a trapezium, a circle, and an ellipse.

Preferably the pattern comprises a shape having an outline, and preferably inboard of the outline the coating has been processed.

Preferably the pattern comprises a shape having an outline, and preferably inboard of the outline the coating has not been processed.

Preferably the pattern is in the form of a bar code or a Quick Response (QR) code.

Preferably the glass beneath the pattern is weakened.

In some embodiments, following step (ii) the method comprises a heating step.

In such embodiments, preferably the heating step occurs before step (iii). Preferably the heating step comprises heating the first sheet of glass to a suitably high temperature such that the coating adheres to the first region of the first major surface of the first sheet of glass. Such embodiments are particularly useful when the coating comprises a frit.

In some embodiments wherein a heating step follows step (ii), the heating step comprises a shaping step, wherein prior to the shaping step the first sheet of glass has a first shape in a first direction, and following the shaping step, the first glass sheet has a second shape in the first direction, the first shape being different to the second shape and the second shape preferably being curved in one or more direction. In such embodiments, it is preferred that prior to the shaping step, the first sheet of glass is flat, or substantially flat.

Preferably the shaping step takes place after the heating step, but the heating step and the shaping step may overlap in time such that the first sheet of glass is heated during the shaping step.

When the heating step comprises a shaping step, the first sheet of glass sheet is heated to a temperature to be shapeable during the shaping step. Preferably the first sheet of glass is heated to a temperature between 580°C and 680°C.

Preferably the shaping step comprises supporting the first sheet of glass on a shaping member.

Preferably the shaping step comprises shaping the first sheet of glass by sagging under gravity and/or pressing between a pair of shaping members having complementary shaping surfaces.

Preferably the first sheet of glass is bent at the same time as another sheet of glass. In such embodiments, the first sheet of glass and the another sheet of glass are preferably a nested pair.

In some embodiments a second region of the first major surface of the first sheet of glass is coated with a coating. The coating on the second region of the first major surface of the first sheet of glass may be the same or different to the coating on the first region of the first major surface of the first sheet of glass.

The coating on the second region of the first major surface of the first sheet of glass has a thickness and the thickness of the coating on the second region of the first major surface of the first sheet of glass may be the same or different to a thickness of the coating on the first region of the first major surface of the first sheet of glass.

Preferably the second region of the first major surface of the first sheet of glass is spaced apart and separate from the first region of the first major surface of the first sheet of glass.

In some embodiments the first sheet of glass has a thickness between 1mm and 3mm, preferably between 1.4mm and 2.8mm, more preferably between 1.6mm and 2.3mm.

In some embodiments the first sheet of glass comprises a sheet of soda-lime-silicate glass. Soda- lime-silicate glass is often referred to as soda-lime-silica glass, or simply a sheet “soda-lime” glass. In some embodiments the first sheet of glass comprises a sheet of alkali aluminosilicate glass.

In some embodiments the first sheet of glass comprises at least about 6wt% (percent by weight) aluminium oxide (AI2O3).

In some embodiments the first sheet of glass is chemically strengthened i.e. chemically strengthened glass.

When the first sheet of glass is chemically strengthened, preferably the first sheet of glass has a thickness less than 1.2mm, more preferably between 0.3mm and 1mm, even more preferably between 0.4mm and 0.9mm.

In some embodiments wherein the glazing comprises a second sheet of glass, preferably the second sheet of glass has a thickness between 1mm and 3mm, more preferably between 1 ,4mm and 2.8mm, even more preferably between 1.6mm and 2.3mm.

In some embodiments wherein the glazing comprises a second sheet of glass, preferably the second sheet of glass comprises a sheet of soda-lime-silicate glass. Soda-lime-silicate glass is often referred to as soda-lime-silica glass, or simply a sheet “soda-lime” glass.

In some embodiments wherein the glazing comprises a second sheet of glass, preferably the second sheet of glass comprises a sheet of alkali aluminosilicate glass.

In some embodiments wherein the glazing comprises a second sheet of glass, preferably the second sheet of glass comprises at least about 6wt% (percent by weight) aluminium oxide (AI2O3).

In some embodiments wherein the glazing comprises a second sheet of glass, preferably the second sheet of glass is chemically strengthened i.e. chemically strengthened glass.

When the second sheet of glass is chemically strengthened, preferably the second sheet of glass has a thickness less than 1.2mm, more preferably between 0.3mm and 1mm, even more preferably between 0.4mm and 0.9mm.

In some embodiments the glazing is a laminated glazing comprising the first sheet of glass joined to a second sheet of glass by an interlayer structure comprising a first sheet of adhesive interlayer material, the second major surface of the first sheet of glass facing the first sheet of adhesive interlayer material, and wherein the first sheet of glass is an inner pane such that when the laminated glazing is installed in a vehicle, the inner pane faces the interior of the vehicle.

In such embodiments the laminated glazing is preferably a vehicle windscreen. The vehicle windscreen is configured to have a lower peripheral edge and an upper peripheral edge, the upper peripheral edge of the vehicle windscreen being closer to the roof of the vehicle than the lower peripheral edge when the vehicle windscreen is installed in the vehicle. Preferably the coating on the first region of the first major surface of the first sheet of glass is processed inboard of the lower peripheral edge of the vehicle windscreen preferably by between j cm and k cm from the lower peripheral edge of the vehicle windscreen, wherein j= , or 2, or 3, or 4, or 5, or 6, or 7, or 8, or 9, or 10 and k = 5, or 10, or 15, or 20, or 25, or 25, with the proviso that k > j.

Preferably the first major surface of the first sheet of glass is a concave surface and the second major surface of the first sheet of glass is a concave surface.

The second sheet of glass has a first major surface and a second opposing major surface. In such embodiments the second major surface of the second sheet of glass faces the first sheet of adhesive interlayer material.

The first major surface of the second sheet of glass has a first region, the first region of the first major surface of the second sheet of glass being at least partially aligned with the first region of the first major surface of the first sheet of glass when viewed normal to the first region of the first major surface of the second sheet of glass.

Preferably following an impact with a suitable impactor at an impact location on the first region of the first major surface of the second sheet of glass, the laminated glazing develops cracks in the vicinity of the impact location in less than 2ms.

In such embodiments, preferably the laminated glazing fully breaks within 2ms, more preferably 1ms of the time taken for the cracks to develop.

Preferably the impactor is as described in UN Regulation No. 127 (E/ECE/324/Rev.2/Add. 126/Rev.2).

Preferably the impactor has a mass between 3kg and 6kg, more preferably between 4kg and 5kg, even more preferably a mass of 4.5kg.

Preferably the impactor is a sphere or a spheroid and preferably has a diameter between 15cm and 20cm, more preferably between 16 and 17cm.

Preferably when the impactor strikes the impact location, the velocity thereof is between 20km/h and 50km/h, more preferably between 35km/h and 45km/h, even more preferably 40km/h.

Preferably the impactor impacts the impact location by falling under gravity alone.

Preferably the time taken for the laminated glazing to break upon being impacted by the impactor is at least 50%, or 60%, or 70% or 80% shorter than the time taken for the laminated glazing to break without the laminated glazing having a first sheet of glass that has been processed in accordance with the present invention. The present invention also provides from a second aspect a glazing comprising a first sheet of glass having a first major surface and a second opposing major surface and a coating on at least a first region of the first major surface of the first sheet of glass; there being a first region of the second major surface of the first sheet of glass aligned with the first region of the first major surface of the first sheet of glass, wherein between the first region of the first major surface of the first sheet of glass and the first region of the second major surface of the first sheet of glass is at least one weakness to weaken the first sheet of glass.

Preferably the weakness comprises a line of weakness.

Preferably the weakness comprises a crack.

Preferably the glazing is a pane in a vehicle glazing, in particular a vehicle windscreen or a vehicle side window or a vehicle rear window.

Preferably the coating comprises a frit.

Preferably the coating comprises a frit of the type of frit used to provide an automotive glazing with an obscuration band.

Preferably the coating has a thickness between 1pm and 100pm, more preferably between 5 pm and 75pm, even more preferably between 10pm and 60pm.

In some embodiments the glazing is a laminated glazing comprising a second sheet of glass and an interlayer structure comprising at least a first sheet of adhesive interlayer material, the laminated glazing being arranged with the interlayer structure between the first sheet of glass and the second sheet of glass.

Preferably the second major surface of the first sheet of glass faces the first sheet of adhesive interlayer material

Preferably the first major surface of the first sheet of glazing material is concave.

Preferably the laminated glazing is curved in at least one direction. Preferably the radius of curvature in the at least one direction is between 500mm and 20000mm, more preferably between 1000mm and 8000mm.

Preferably the first sheet of adhesive interlayer material comprises polyvinyl butyral (PVB), acoustic modified PVB, a copolymer of ethylene, such as ethylene vinyl acetate (EVA), polyvinyl chloride (PVC), ethyl methyl acrylate (EMA) copolymer, polyurethane, in particular a thermoplastic polyurethane (TPU), or a liquid curable resin such as Uvekol.

Preferably the interlayer structure comprises 2, or 3, or 4, or 5, or 6, or 7, or 8, or 9, or 10, or more, sheets of adhesive interlayer material. Each sheet of adhesive interlayer material may be the same type i.e. all PVB and may all have the same thickness. Preferably the first sheet of adhesive interlayer material has a thickness between 0.3mm and 2.3mm, more preferably between 0.3mm and 1.6mm, most preferably between 0.3 and 0.8mm.

Preferably the interlayer structure comprises at least one sheet of polyester, more preferably as least one sheet of polyethylene terephthalate (PET), and preferably the at least one sheet of polyester carries on at least one major surface thereof an optically transparent coating that reflects infrared radiation.

As is conventional in the art, surface one of a laminated glazing is an outermost surface of the laminated glazing and surface four of the laminated glazing is an inner facing surface being defined in relation to a vehicle interior in which the laminated glazing is installed.

Preferably the first major surface of the first sheet of glass is surface four of the laminated glazing.

In some embodiments the glazing is a laminated glazing comprising a second sheet of glass and an interlayer structure comprising at least a first sheet of adhesive interlayer material, the laminated glazing being arranged with the interlayer structure between the first sheet of glass and the second sheet of glass and wherein the first major surface of the first sheet of glass faces the first sheet of adhesive interlayer material.

Preferably the second major surface of the first sheet of glass is surface four of the laminated glazing.

Other embodiments of the second aspect of the present invention have other preferable features.

Preferably the first sheet of glass has a thickness between 1mm and 3mm, preferably between 1.4mm and 2.8mm, more preferably between 1.6mm and 2.3mm.

Preferably the first sheet of glass comprises a sheet of soda-lime-silicate glass. Soda-lime-silicate glass is often referred to as soda-lime-silica glass, or simply a sheet “soda-lime” glass.

Preferably the first sheet of glass comprises a sheet of alkali aluminosilicate glass.

Preferably the first sheet of glass comprises at least about 6wt% (percent by weight) aluminium oxide (AI2O3).

Preferably the first sheet of glass is chemically strengthened i.e. chemically strengthened glass.

When the first sheet of glass is chemically strengthened, preferably the first sheet of glass has a thickness less than 1.2mm, more preferably between 0.3mm and 1mm, even more preferably between 0.4mm and 0.9mm.

Preferably the first major surface of the first sheet of glass is concave. Preferably the first sheet of glass is curved in at least one direction. Preferably the radius of curvature in the at least one direction is between 500mm and 20000mm, more preferably between 1000mm and 8000mm.

Preferably the coating has a pattern therein or thereon. Preferably the pattern includes at least a void in the coating on the first region of the first major surface of the first sheet of glass. Preferably the void extends through a thickness of the coating to the glass surface or only part way through the thickness of the coating.

Preferably the pattern is in the form of a line, which may be straight or curved.

Preferably the pattern comprises at least one of a square, a rectangle, a triangle, a trapezium, a circle, and an ellipse.

Preferably the pattern comprises a shape having an outline, and preferably inboard of the outline the coating has been processed.

Preferably the pattern is in the form of a bar code or a Quick Response (QR) code.

Preferably the glass beneath the pattern is weakened.

Preferably the pattern is inboard a lower peripheral edge of the glazing, preferably inboard the lower peripheral edge of the glazing by between 2cm and 40cm, more preferably by between 5cm and 25cm or 30cm or 35cm.

In some embodiments the glazing is a laminated glazing comprising the first sheet of glass joined to a second sheet of glass by an interlayer structure comprising a first sheet of adhesive interlayer material, and wherein the first sheet of glass is an inner pane.

Preferably the second major surface of the first sheet of glass faces the first sheet of adhesive interlayer material.

Preferably the second major surface of the first sheet of glass is a convex surface and the first major surface of the first sheet of glass is a concave surface.

The second sheet of glass has a first major surface and a second opposing major surface and the laminated glazing is arranged such that the second major surface of the second sheet of glass faces the first sheet of adhesive interlayer material.

The first major surface of the second sheet of glass has a first region, the first region of the first major surface of the second sheet of glass being at least partially aligned with the first region of the first major surface of the first sheet of glass when viewed normal to the first region of the first major surface of the second sheet of glass. Preferably following an impact with a suitable impactor at an impact location on the first region of the first major surface of the second sheet of glass, the laminated glazing develops cracks in the vicinity of the impact location in less than 2ms.

In such embodiments, preferably the laminated glazing fully breaks within 2ms, preferably 1ms of the time taken for the cracks to develop.

Preferably the impactor is as described in UN Regulation No. 127 (E/ECE/324/Rev.2/Add. 126/Rev.2).

Preferably the impactor has a mass between 3kg and 6kg, more preferably between 4kg and 5kg, even more preferably a mass of 4.5kg.

Preferably the impactor is a sphere or a spheroid and preferably has a diameter between 15cm and 20cm, more preferably between 16 and 17cm.

Preferably when the impactor strikes the impact location, the velocity thereof is between 20km/h and 50km/h, more preferably between 35km/h and 45km/h, even more preferably 40km/h.

Preferably the impactor impacts the impact location by falling under gravity alone.

Preferably the time taken for the laminated glazing to break upon being impacted by the impactor is at least 50%, or 60%, or 70% or 80% shorter than the time taken for the laminated glazing to break without the laminated glazing having a first sheet of glass that has been processed in accordance with the present invention.

In some embodiments the glazing is a laminated glazing comprising the first sheet of glass joined to a second sheet of glass by an interlayer structure comprising a first sheet of adhesive interlayer material, and wherein the first sheet of glass is an outer pane.

Preferably the first major surface of the first sheet of glass faces the first sheet of adhesive interlayer material such that the second major surface of the first sheet of glass is surface one.

The present invention will now be described with reference to the following figures in which:

Figure 1 is a schematic cross-sectional representation of a laminated glazing according to the present invention;

Figure 2 is a plan view of a laminated glazing in accordance with the present invention;

Figure 3 is the view from inside a vehicle that has a windscreen in accordance with the present invention;

Figure 4 is similar to figure 2 and is a plan view of another laminated glazing in accordance with the present invention; Figure 5 is similar to figure 2 and is a plan view of another laminated glazing in accordance with the present invention;

Figure 6 is a schematic cross-sectional representation of a glazing according to the present invention to illustrate a coating before being processed by a laser;

Figure 7 is a schematic cross-sectional representation of the glazing in figure 6 after being processed by a laser;

Figure 8 is a schematic isometric representation of a glazing with a barcode in the obscuration band; and

Figure 9 is a schematic cross-sectional representation of a laminated glazing with an obscuration band on surface four that has been processed according to the present invention.

Figure 1 shows a cross section of a curved laminated glazing in accordance with the present invention.

The laminated glazing 1 has a first sheet of glass 3 of soda-lime-silicate glass having a composition such as clear float glass, typically with the addition of iron oxide as a tinting agent to provide the laminated glazing with some form of solar control. The first sheet of glass 3 has a thickness of 1 ,6mm although the thickness may be in the range 1 ,4mm to 2.5mm or in the range 1 ,6mm to 2.3mm.

A typical soda-lime-silicate glass composition is (by weight), SiO ₂ 69 - 74 %; AI2O3 0 - 3 %; Na ₂ 0 10 - 16 %; K ₂ O 0 - 5 %; MgO 0 - 6 %; CaO 5 - 14 %; SO3 0 - 2 %; Fe ₂ O ₃ 0.005 - 2 %. The glass composition may also contain other additives, for example, refining aids, which would normally be present in an amount of up to 2 %. The soda-lime-silicate glass composition may contain other colouring agents such as CO3O4, NiO and Se to impart to the glass a desired colour when viewed in transmitted light. The transmitted glass colour may be measured in terms of a recognised standard such as BS EN410.

The laminated glazing 1 also has a second sheet of glass 7 of soda-lime-silicate glass having a thickness of 2.3mm, but the second sheet may have a thickness may be in the range 1 ,4mm to 2.5mm and is preferably not as thick as the first sheet 3.

Both the first and second sheets of glass 3, 7 may be made using a float process.

The first sheet of glass 3 is joined to the second sheet of glass 7 by an adhesive interlayer 5. The adhesive interlayer 5 is a 0.76mm thick sheet of PVB. The adhesive interlayer 5 may have a thickness between 0.3mm and 1.8mm.

Other suitable adhesive interlayers include PVC, EVA, EMA and polyurethane.

The laminated glazing 1 is curved in one or more directions. The radius of curvature in one of the one or more directions is between 1000mm and 8000mm. When the laminated glazing is curved in two directions, suitably each direction of curvature is orthogonal to the other. Suitably the radius of curvature in one or both directions of curvature is between 1000mm and 8000mm.

The first sheet of glass 3 has a convex first surface 9 and an opposing concave second surface 11. The second sheet of glass 7 has a convex first surface 13 and an opposing concave second surface 15. The convex surface 9 of the first sheet of glass 3 is in contact with the adhesive interlayer 5 and the concave surface 15 of the second sheet of glass 7 is in contact with the adhesive interlayer 5.

Using conventional nomenclature, the convex surface 13 of the second sheet of glass 7 is “surface one” (or SI) of the laminated glazing 1, the concave surface 15 of second sheet of glass 7 is “surface two” (or S2) of the laminated glazing 1, the convex surface 9 of the first sheet of glass 3 is “surface three” (or S3) of the laminated glazing 1 and the concave surface 11 of the first sheet of glass 3 is “surface four” (or S4) of the laminated glazing 1.

There is an array of processed regions 17 on surface four (the concave surface 11 of the first sheet of glass 3).

Figure 2 is a plan view of the laminated glazing 1 in the direction of arrow 10 of figure 1.

In figure 2, the periphery of the laminated glazing 1 is typical of a vehicle windscreen. Extending around the periphery of the concave surface 11 is an obscuration band 2 of a fired frit material having a thickness of about 50pm. The frit material was applied to a sheet of flat glass using a screen printing process. The flat glass sheet was heated and shaped to the desired curvature. Heating the glass causes the frit to sinter and become fused to the glass surface.

The laminated glazing 1 has a lower peripheral edge 19 and inboard of the lower peripheral edge 19 are six processed regions 17a, 17b, 17c, 17c, 17e, 17f that form the array of processed regions 17.

Each processed region was formed after shaping and after the frit material had become fused to the glass surface by directing a laser beam having a wavelength of 1064nm towards the obscuration band at a sufficient power density to remove the fused frit material. In this example each processed region was processed the same way, although different regions may be processed differently, for example, to remove a different amount of fused frit material. Processing may completely remove the fused frit material in the region being processed.

Beneath the processed regions 17a, 17b, 17c, 17c, 17e, 17f the first sheet of glass 3 has been weakened due to the presence of lines of weakness in the form of cracks being formed in the glass during processing.

For a given processed region 17a, 17b, 17c, 17c, 17e, 17f the respective cracks thereof may be at least partially in the surface 11 and/or in the volume of glass beneath the respective processed region. In this example each processed region 17a, 17b, 17c, 17c, 17e, 17f is a square with 2cm sides such that the area of each processed region 17a, 17b, 17c, 17c, 17e, 17f is 4cm ² .

The processed regions 17a, 17b, 17c, 17c, 17e, 17fare equally spaced such that the space between processed region 17a and 17b is the same as the space between processed region 17b and 17c, and so on.

The processed regions 17a, 17b, 17c, 17c, 17e, 17f lie in a line that is parallel to the lower peripheral edge 19.

By providing the processed regions 17a, 17b, 17c, 17c, 17e, 17f, in the event of an impact on the convex surface 13 of the second sheet of glass 7, the first sheet of glass 3 can break more easily so that the rigidity of the laminated glazing 1 is reduced. When the laminated glazing 1 is installed as a windscreen in a vehicle, in the event of a pedestrian being involved in a collision with the vehicle, the reduction in rigidity of the windscreen upon an impact with the convex surface 13 reduces the seriousness of injury to the pedestrian.

Although figures 1 and 2 have only six processed regions, there may be more than six processed regions or less than six processed regions. In some embodiments there are seven or eight or nine or ten or more processed regions. In some embodiments, there are one, or two, or three, or four, or five processed regions. It is preferred to have the processed regions equally spaced from one another.

Another embodiment of the present invention is shown in figure 3.

Figure 3 shows the view from inside a vehicle that has a windscreen 100 in accordance with the present invention.

The windscreen 100 is essentially the same as the laminated glazing 1 previously described. The vehicle windscreen has a lower peripheral edge extending between the points E and F. The vehicle windscreen has an upper peripheral edge extending between the points D and G. The lower peripheral edge is near the vehicle dashboard and the upper peripheral edge is near the vehicle roof.

On surface four of the windscreen is an obscuration band 171 that has a peripheral edge shown as dotted line 171’. Inboard of the peripheral edge 171’ is the vision region of the vehicle windscreen 100.

On surface four of the windscreen 100 in the region of the obscuration band are a plurality of processed regions as described with reference to figure 2 i.e. processed with a laser. There is a first array of processed regions 174 that has twenty square regions (only one of which is labelled 175). Each square region 175 has dimensions of between Ixlcm and 3x3cm. It is preferred all the squares 175 have the same size and/or area. The squares 175 are arranged in a line running parallel to the lower peripheral edge E-F i.e. the lower sides of the squares 175 are parallel to the lower peripheral edge E-F. The squares 175 may be orientated differently. In this embodiment also on surface four of the windscreen 100 is a second array of processed regions 172 running along the left hand peripheral edge D-E of the windscreen 100 and a third array of processed regions 176 running along the right hand peripheral edge. The second array of processed regions 172 has seven square regions (only one of which is labelled 173) with a lower side thereof being parallel to the left hand peripheral edge D-E. The third array of processed regions 176 also has seven square regions (only one of which is labelled 177) with a lower side thereof being parallel to the right-hand peripheral edge F-G.

Each of the processed regions in the second and third arrays are the same size and/or have the same area.

With reference to figure 2, the processed regions are made by directing a Nd:YVC>4 laser beam having a wavelength of 1064nm towards the fired obscuration band to weaken the glass beneath the obscuration band in the vicinity of the processed region. Alternatively, the processed regions may be made by directing a carbon dioxide laser beam having a wavelength of 10.6pm towards the fired obscuration band to weaken the glass beneath the obscuration band in the vicinity of the processed region

Figure 4 is a plan view towards surface four (S4) of another laminated glazing 30 having a similar construction to the laminated glazing 1. Figure 4 is similar to the view in figure 2 so the view thereof is in the direction of arrow 10 of figure 1.

The laminated glazing 30 has a first sheet of glass 32 having a thickness of 1 ,6mm joined to a second sheet of glass having a thickness of 2.1mm by means of a sheet of PVB having a thickness of 0.76mm.

In figure 4, the periphery of the laminated glazing 30 is typical of a vehicle windscreen. The laminated glazing 30 has a lower peripheral edge 34 and an opposite upper peripheral edge (not labelled). Inboard of the periphery of the major surface of the first sheet of glass 32 there is an obscuration band 35 on surface four of the laminated glazing 30.

Inboard of the lower peripheral edge 34 and within the region of the obscuration band 35 part of surface four has been processed with a laser as previously described to provide a rectangular processed region 36. The rectangular processed region 36 has a width of about 1mm, although the width thereof may be between 0. 1mm and 5mm. The rectangular processed region 36 has a lower edge 38 that is parallel to the lower peripheral edge 34 of the laminated glazing.

The frit forming the obscuration band may be completely removed in the rectangular processed region 36. Alternatively, the rectangular processed region 36 may comprise an array of lines or a grid to define the rectangular processed region 36. Figure 5 is a plan view towards surface four of another laminated glazing 40 having a similar construction to the laminated glazing 1 (so is a view in the direction of arrow 10 of figure 1).

The laminated glazing 40 comprises a first sheet of soda-lime-silicate glass 42 having a thickness of 1.8mm joined to a second sheet of soda-lime-silicate glass having a thickness of 1.8mm by means of a sheet of PVB having a thickness of 0.76mm.

The laminated glazing 40 has a lower peripheral edge 44 that is curved and inboard of the lower peripheral edge 44 part of surface four has been processed with a laser to provide a processed region 46.

The processed region 46 has three portions 46a, 46b and 46c forming the continuous processed region 46, although the three portions 46a, 46b and 46c may be separate.

There is an obscuration band 43 on surface four of the laminated glazing 40. The processed regions 46a, 46b, 46c are in the area of the obscuration band 43.

Each portion 46a, 46b, 46c is rectangular and the portions are arranged to substantially follow the contour of the lower edge 44.

Also provided on surface four of the laminated glazing 40 is a second processed region 48.

The second processed region 48 is curved and has a lower edge 49 that is substantially parallel to the lower edge 44 of the laminated glazing 40. The second processed region 48 also has an upper edge 49’ that is preferably parallel to the lower edge 49. The spacing of the upper and lower edges is between 0.5mm and 5mm, i.e. 1mm to 5mm, and may be about 2mm.

The second processed region 48 is also in the area of the obscuration band 43.

The laminated glazing 40 may be provided with either or both processed regions 46, 48. If there are two processed regions 46, 48 (as shown in figure 5), the relative positions thereof may be switched such that the second processed region 48 is between the lower edge 44 and the processed region 46.

The processed regions 46, 48 are symmetrical about the axis m-m ’, which is the centreline of the laminated glazing 40.

Figure 6 is used to illustrate how a glazing according to the present invention is made.

Figure 6 shows a schematic cross-sectional representation of glazing 50 comprising a sheet of soda- lime-silicate glass 51 that has a first major surface 52 and an opposing second major surface 52’ and a thickness of about 1 ,8mm. Around the periphery of the first major surface 52 is an obscuration band 53. Inboard of the obscuration band 53 there is a through vision region of the glazing 50.

The obscuration band 53 is a fired frit and was applied to the sheet of soda-lime-silicate glass 51 using conventional techniques. For example, the frit was initially applied to the first major surface 52 of the sheet of soda-lime- silicate glass 51 using a conventional screen printing process to coat a portion thereof i.e. around the periphery. Thereafter, the temperature of the coated glass sheet was raised to cause the frit to sinter and fuse to the first major surface 52 of the sheet of soda-lime-silicate glass 51 thereby providing the obscuration band 53 having a thickness of about 50pm. In this example the obscuration band 53 is optically opaque.

Once cooled to ambient conditions (for example room temperature i.e. a temperature of about 20°C), a laser 55 was used to direct a laser beam 57 towards the surface of the fused obscuration band 53 to process a region thereof.

The laser beam 57 had a wavelength of 1064nm and was focussed to a circular spot size of about 0.5mm. The power of the laser was sufficient to remove some of the obscuration band and to weaken the glass beneath the obscuration band in the vicinity of the region being processed. Several cracks were observed in the body of the glass close to where the laser beam 57 was incident on the obscuration band 53.

The glazing 50 following the laser processing described above is shown in figure 7 and labelled as glazing 50’. The thickness of the obscuration band 53 in the region 54 that was struck by the laser beam 57 has been reduced compared to the unprocessed thickness of the obscuration band 53. Cracks 56 were observed beneath the region 54 of the obscuration band 53. Cracks may also occur at the interface between the obscuration band 53 and the sheet of soda-lime-silicate glass 51 in the processed region 54. Such surface cracks may extend into the body of glass beneath the region 54.

In this example the laser beam 57 is directed towards the exposed surface 53’ of the fused obscuration band 53. That is, in this example the laser beam does not first pass through the second major surface 52’ before striking the fused obscuration band 53 at the interface between the glass sheet 51 and the fused obscuration band 53.

Figure 8 shows how a pattern 59 may be provided in the obscuration band 53 by processing the obscuration band 53 with a laser as described above.

The glazing 50” shown in figure 8 is essentially the same as the glazing 50 and 50’ but has been processed further to provide the pattern 59 in the obscuration band.

In this example the pattern 59 is in the form of a bar code but may be in the form of a logo and/or a QR code. By processing the glazing 50” in accordance with the present invention, the pattern 59 is able to be used to identify the glazing when used as a bar code, QR code, logo or the like, and to have a weakened region such that the glazing 50” is able to break more easily when impacted, in particular when impacted with an impact on the opposite surface to which the obscuration is on (i.e. with reference to figure 6, major surface 52’). The pattern 59 is arranged near a lower peripheral edge of the processed glazing 50”. Figure 9 shows another glazing 60 in accordance with the present invention. The glazing 60 is a laminated glazing and comprises the processed glazing 50’ shown in figure 7 joined to a second sheet of glass 61 having a thickness of 2.1mm by a sheet of PVB 63 having a thickness of 0.8mm. The processed glazing 50” shown in figure 8 may be used instead of the processed glazing 50’.

Due to the cracks 56 below obscuration band (i.e. in the vicinity of the region 54 that was processed with a laser beam as described with reference to figures 6 and 7 and the related description thereof), the sheet of soda-lime-silicate glass 51 is weakened such that an impact on the opposite major surface of the laminated glazing 60 in a region opposite the region 54 (as shown by arrow 65) is able to cause the laminated glazing 60 to break more easily. This particularly useful when the laminated glazing 60 is configured as a vehicle windscreen and the obscuration band 53 is on surface four of the laminated glazing. An impact on surface one of the laminated glazing at a region opposite the region 54 can cause the vehicle windscreen to break due to the cracks 56 causing the windscreen to lose rigidity. This may be used to reduce the potential injury to a pedestrian who may be involved with a collision with a vehicle in which the laminated glazing 60 is installed, with the first sheet of soda-lime-silicate glass 51 facing the interior of the vehicle.

If the glazing 50” is used instead of the glazing 50’, the pattern 59 is preferably along and spaced apart from a lower peripheral edge of the vehicle windscreen (with reference to figure 3, the lower peripheral edge E-F).

In an alternative embodiment to that shown in figure 9, the first sheet of soda-lime-silicate glass 51 facing the interior of the vehicle is arranged such that the obscuration band is adjacent the sheet of PVB 63. That it, the obscuration band 53 is between the first sheet of soda-lime-silicate glass 51 and the sheet of PVB 63. Using conventional nomenclature for the laminated glazing, in such an embodiment the obscuration is on surface three (and not surface four as shown in figure 9).

In another alternative embodiment to that shown in figure 9, the second sheet of glass 61 also has an obscuration band thereon. The obscuration band on the second sheet of glass 61 may be configured in substantially the same way as the obscuration band 53 and may include one or more processed region thereof. The obscuration band on the second sheet of glass 61 may be on an exposed surface thereof, or the obscuration band on the second sheet of glass 61 may positioned between the second sheet of glass 61 and the sheet of PVB 63.

In another alternative embodiment to that shown in figure 9, the laminated glazing is installed in a vehicle such that the second sheet of glass 61 faces the interior of the vehicle. The obscuration band may be positioned on an exposed major surface of the first sheet of soda-lime-silicate glass 51 or may be positioned between the sheet of PVB 63 and the first sheet of soda-lime-silicate glass 51. In such embodiments, the first sheet of soda-lime-silicate glass 51 may be referred to as the outer pane of the laminated glazing. Using conventional nomenclature for such a laminated glazing, the obscuration band 53 in such an embodiment is on surface one or surface two (and not surface four as shown in figure 9).

Although in figures 6-9 the glazings are shown as being flat, the glazings may be curved having been shaped by a suitable shaping process such as gravity bending or press bending, where an initially flat sheet of glass is heated to a suitable temperature for shaping and subsequently shaped. The coating (i.e. a frit for an obscuration band) may be applied to the initially flat sheet of glass and during the shaping process the coating becomes adhered to the glass sheet.

It has been found that by having one or more processed regions in the glass sheet according to the present invention that the glass sheet is easier to break. This is particularly useful when the glass sheet is used as a pane of a laminated glazing, for example as the inner pane of a laminated windscreen for a vehicle, because it has been found that the inner facing glass sheet is easier to break in the event of a pedestrian colliding with the outer facing surface of the laminated windscreen (i.e. surface one). The processed regions may be positioned not to be visually distracting to the vehicle driver.