LAMINATED GLAZING WITH ELECTRICALLY CONTROLLABLE OPTICAL PROPERTIES FOR A VEHICLE EQUIPPED WITH A SEMITRANSPARENT REFLECTIVE PRINTED INSCRIPTION ON THE EXTERIOR FACE OF A VEHICLE

Abstract

A laminated glazing for a vehicle provided with an inscription includes an interior glass sheet and an exterior glass sheet, each including an inner face and an outer face, and including, between the inner faces of the two glass sheets, an interlayer including at least two outer layers in a material selected from polyvinyl butyral (PVB), polyethylene vinyl acetate (EVA) and polyurethane (PU) and mixtures thereof, the outer layers being joined by a functional element (4) of liquid crystals dispersed in a polymer matrix. The functional element includes a liquid crystal active layer between two electrically conductive layers, themselves disposed between two carrier films. The inscription is a semi-transparent reflective layer and the inscription is printed on the exterior glass sheet on the outer face.

Claims

1. A laminated glazing for a vehicle provided with an inscription comprising an interior glass sheet and an exterior glass sheet, each comprising an inner face and an outer face, and comprising, between the inner faces of the interior and exterior glass sheets, an interlayer comprising at least two outer layers and in a material selected from polyvinyl butyral (PVB), polyethylene vinyl acetate (EVA) and polyurethane (PU) and mixtures thereof, said outer layers being joined by a functional element of liquid crystals dispersed in a polymer matrix, said functional element comprising a liquid crystal active layer between two electrically conductive layers, the two electrically conductive layers being disposed between two carrier films, wherein the inscription consists of a semi-transparent reflective layer and said inscription is printed on the exterior glass sheet on the outer face.

2. The laminated glazing according to claim 1, wherein the interior glass sheet and/or the exterior glass sheet comprises at least one coating.

3. The laminated glazing according to claim 1, wherein one of the two outer layers or each of the two outer layers has a thickness between 0.2 mm and 2.0 mm.

4. The laminated glazing according to claim 3, wherein the two outer layers are polyvinyl butyral (PVB) layers.

5. The laminated glazing according to claim 4, wherein one of the two outer PVB layers or each of the two outer PVB layers comprises at least one plasticizer.

6. The laminated glazing according to claim 1, wherein the two carrier films are made of polyethylene terephthalate (PET).

7. The laminated glazing according to claim 1, wherein a region of the laminated glazing provided with the semi-transparent reflective layer forming the printed inscription has, in a wavelength range of the visible spectrum, a light transmission greater than 0% and an external light reflection between 10% and 30%.

8. The laminated glazing according to claim 1, wherein the inscription is printed by screen printing, pad printing.

9. The laminated glazing according to claim 1, wherein a size of the inscription is at least 0.2 mm.

10. The laminated glazing according to claim 1, wherein the printed inscription covers from 10% to 90% of a total surface of the exterior glass sheet.

11. The laminated glazing according to claim 1, wherein the semi-transparent reflective layer forming the inscription consists essentially of one or more metal oxides.

12. The laminated glazing according to claim 11, wherein the one or more metal oxides are selected from aluminium oxide, tin oxide, titanium oxide, copper oxide, chromium oxide, cobalt oxide iron oxide, manganese oxide, zirconium oxide, cerium oxide, yttrium oxide, silver oxide, gold oxide, platinum oxide and palladium oxide and a mixture thereof.

13. A rear window, side window or roof window of a vehicle comprising a laminated glazing according to claim 1.

14. A method comprising providing a laminated glazing according to claim 1 as a rear window, side window or roof window of a motor vehicle.

15. A method for manufacturing a laminated glazing for vehicle having electrically controllable optical properties comprising: a) providing an interior glass sheet and an exterior glass sheet, b) printing an inscription consisting of a semi-transparent reflective layer on an outer face of the exterior glass sheet, c) curing said printed glass sheet by heat treatment in air at a temperature between 500 C. and 700 C., d) carrying out the forming of the said interior and exterior glass sheets together or separately by heat treatment, e) separating the formed interior and exterior glass sheets, f) arranging between inner faces of the formed interior glass sheet and the formed exterior glass sheet provided with the printed inscription, an interlayer comprising: a first outer layer in a material selected from polyvinyl butyral (PVB), polyethylene vinyl acetate (EVA) and polyurethane (PU) and mixtures thereof, a functional element comprising a liquid crystal active layer between two electrically conductive layers, the two electrically conductive layers being disposed between two carrier films, and a second outer layer in a material selected from polyvinyl butyral (PVB), polyethylene vinyl acetate (EVA) and polyurethane (PU) and mixtures thereof, g) assembling the interior and exterior glass sheets and the interlayer by lamination to form a laminated glazing, and (e) degassing by autoclaving said laminated glazing.

16. The laminated glazing according to claim 3, wherein the thickness is between 0.3 mm and 0.9 mm.

17. The laminated glazing according to claim 7, wherein the light transmission is between 0.5% and 30% and the external light reflection is between 13% and 25%.

18. The laminated glazing according to claim 8, wherein the inscription is printed by screen printing.

19. The laminated glazing according to claim 9, wherein the size of the inscription is at least 0.4 mm.

20. The laminated glazing according to claim 10, wherein the printed inscription covers from 20% to 50% of the total surface of the exterior glass sheet.

Description

EXAMPLES

[0063] In these examples, a sol-gel of the Ferro Lustreflex Silver type is deposited according to the decoration or inscription represented by the black zones of FIG. 2, by wet deposition according to a known screen 25 printing process on the edge of a glass sheet of the Planiclear type (marketed by the applicant company). The inscription thus obtained consists of a semi-transparent reflective layer printed on a sheet of glass which will be arranged in the examples below on a laminated glazing comprising a PDLC functional element on the outer face of a vehicle.

[0064] As can be seen in FIG. 2, the printed inscription partially covers the surface of the exterior glass sheet since the printed inscription covers 40% of the total surface of the glass sheet.

[0065] A laminated glazing comprising a PDLC functional element of the following configuration I is prepared by successively arranging, starting from an interior glass sheet (glass sheet facing the interior of a vehicle) of the Lowe type (marketed by the applicant company), the following elements: [0066] a grey PVB layer with a thickness of 0.38 mm (corresponding to the first outer PVB layer), [0067] a PDLC functional element, [0068] a grey PVB layer with a thickness of 0.38 mm, [0069] a PET layer, [0070] a clear PVB layer with a thickness of 0.38 mm (corresponding to the second outer PVB layer), [0071] an exterior glass sheet (glass sheet facing the outside environment of a vehicle) of the Planiclear type with a printed semi-transparent reflective inscription that is then cured by heat treatment in air.

[0072] Another PDLC laminated glazing comprising a PDLC functional element of the following configuration II is prepared by successively arranging, starting from an inner Lowe type glass sheet, the following elements: [0073] a clear PVB layer with a thickness of 0.38 mm (corresponding to the first outer PVB layer), [0074] a PDLC functional element, [0075] a grey PVB layer with a thickness of 0.38 mm, [0076] a PET layer, [0077] a clear PVB layer with a thickness of 0.38 mm (corresponding to the second outer PVB layer), [0078] an exterior glass sheet (glass sheet facing the outside environment of a vehicle) of the Planiclear type with a printed semi-transparent reflective inscription that is then cured by heat treatment in air.

[0079] For each of the laminated glazing configurations I or II described above, the inscription consisting of a semi-transparent reflective layer is printed: [0080] either on the outer face of the exterior glass sheet (face of the glass sheet facing the outside of the vehicle, commonly called face 1 (F1)), as in the following examples: no. 1a (config. I+(F1)) and 2a (config. II+(F1)), according to the invention, [0081] or on the inner face of the exterior glass sheet (face of the glass sheet facing the interior of the vehicle, towards the outer layer of PVB, commonly called face 2 (F2)), according to the following comparative examples: no. 1b (config. I+(F2)) and 2b (config. II+(F2)), and [0082] or no inscription is printed on the exterior glass sheet according to the following examples no. 1c (config. I) and 2c (config. II).

[0083] Then, an electric current is applied (ON state), or not (OFF state), to each of the laminated glazings (i.e. to each of the examples 1a, 1b, 1c and 2a, 2b, 2c, below), and the values of light transmissions LT and external light reflections LR.sub.ext are measured on the zone (or region) of the glazing provided with the semi-transparent reflective layer forming the printed inscription, as represented in FIG. 2, in the visible spectrum range (wavelengths between 380 nm and 780 nm), according to the methods described in the NF EN 410 (2011) standard. Indeed, FIG. 2 represents a laminated glazing for vehicles with electrically controllable optical properties provided with a printed inscription.

[0084] Measurements are performed using a Perkin Elmer UV/Vis/NIR spectrophotometer LAMBDA 900, with a transmission analysis spot size of 10 mm16 mm and a reflection spot size of 4 mm16 mm.

[0085] The LT is the light transmission indicating the radiant energy transmitted into the vehicle cabin in the optical range of a standard D65 illuminant. The angle of incidence of light on laminated glazing is 90.

[0086] The LR.sub.ext corresponds to the external light reflection from the outside (light reflected to the outside environment, to the outside of a vehicle).

[0087] The results obtained are compiled in Tables 1 and 2 below:

[0088] Results

TABLE-US-00001 TABLE 1 Configura- Face 1 Face 1 Face 2 Face 2 None None tion I 1a ON 1a OFF 1b ON 1b OFF 1c ON 1c OFF LT 1.49 0.97 1.8 1.17 1.82 1.27 LR.sub.ext 16.01 16.03 11.98 12 6.31 6.34

TABLE-US-00002 TABLE 2 Configura- Face 1 Face 1 Face 2 Face 2 None None tion II 2a ON 2a OFF 2b ON 2b OFF 2c ON 2c OFF LT 3.44 3.45 5.52 3.85 5.99 4.1 LR.sub.ext 15.27 15.29 12.27 12.3 6.75 6.78

[0089] The results reported in these tables show that when the inscription consisting of a semi-transparent reflective layer is printed on the outer face, face 1, of the exterior glass sheet, according to the invention, regardless of the configuration (I or II) of a laminated glazing comprising a PDLC element (cf. examples 1a and 2a): [0090] the light transmission of the glazing is maintained in the region where the printed inscription is located, whether in the ON or OFF state, since the value of the LT for a glazing according to the invention is of the same order of magnitude as the LT obtained for the same laminated glazing that does not comprise an inscription (cf. examples LT 1a ON and 2a ON according to the invention compared to examples LT 1c ON and 2c ON glazings without inscription respectively and examples LT 1a OFF and 2a OFF compared to examples LT 1c OFF and 2c OFF respectively), [0091] the external light reflection of the glazing is improved in the area where the printed inscription is located, whether in the ON or OFF state, since: [0092] the value of the LR.sub.ext increases from 6.3% for a laminated glazing of configuration I without inscription / to 12% for the same laminated glazing with an inscription printed on face 2/ to 16% for a laminated glazing according to the invention with the inscription printed on face 1, and [0093] the value of the LR.sub.ext increases from 6.8% for a laminated glazing of configuration II without inscription / to 12.3% for the same laminated glazing with an inscription printed on face 2/ to 15.3% for a laminated glazing according to the invention with the inscription printed on face 1.

[0094] Indeed, it can be seen that the LR.sub.ext obtained for a laminated glazing comprising a PDLC element provided with an inscription printed on the outer face (face 1) of the exterior glass sheet, in accordance with the invention, is higher than the LR.sub.ext obtained for a laminated glazing comprising a PDLC element provided with an inscription printed on the inner face (face 2) of the exterior glass sheet, this shows the importance of the position of the inscription on a laminated glazing comprising a PDLC element (cf. examples LR.sub.ext 1a ON and 2a ON compared to Examples LR.sub.ext 1b ON and 2b ON respectively and Examples LR.sub.ext 1a OFF and 2a OFF compared to Examples LR.sub.ext 1b OFF and 2b OFF respectively).