WO2015118242A1

WO2015118242A1 - Glazing for motor vehicle, comprising an opaque or transparent active film and a photochromic layer

Info

Publication number: WO2015118242A1
Application number: PCT/FR2015/050152
Authority: WO
Inventors: Frederic Guidez; Gerard Jeuffe; Nicolas RILAT
Original assignee: Peugeot Citroen Automobiles Sa
Priority date: 2014-02-07
Filing date: 2015-01-22
Publication date: 2015-08-13
Also published as: FR3017331A1

Abstract

The invention relates to a motor vehicle comprising two sheets of glass (2, 3) separated by an intermediate layer of transparent plastic material (4) and an active film (5) that can be powered by an electrical energy source in order to switch from a substantially opaque state, when the film is not being powered, to a substantially transparent state, when the film (5) is being powered by said electrical energy source, said glazing being characterised in that it also comprises a passive photochromic layer (8) which can darken when the sunlight exceeds a pre-determined threshold and reduces the opacity of the glazing.

Description

GLAZING FOR A MOTOR VEHICLE COMPRISING AN OPAQUE OR TRANSPARENT ACTIVE FILM AND A PHOTOCHROMIC LAYER

The present invention relates to a motor vehicle glazing comprising two glass sheets separated by an intermediate layer or intermediate layers of transparent plastic material.

The invention is preferably applied to the roof glazing or roof of a motor vehicle to replace the curtain called velum or windshields to replace sunshades.

Figure 1 shows the interior of a motor vehicle whose roof or roof is equipped with a glazing 1.

Motor vehicle roof or pavilion glazings generally have an internal blackout curtain.

This curtain (not shown in Figure 1) is slidably mounted in a frame located under the glazing between an open position and a closed position of concealment.

This curtain is necessary to protect the occupants of the vehicle in case of strong sunlight.

This curtain and the frame that supports it increases the cost of the entire glazing.

In addition, this curtain, which is mounted inside the vehicle under the roof glazing, decreases the height of the space above the head of the occupants of the vehicle.

Also known are roof or roof glazings comprising, as shown in the sectional views of Figures 2 to 5, two glass sheets 2, 3 separated by a layer 4 of transparent plastic material, such as PVB (polyvinyl butyral) .

In this layer of transparent plastic material is embedded an active film 5 which can be powered by a source of electrical energy connected to a conductor 6.

The active film 5 can thus pass from a substantially opaque state, when this film 5 is not powered (see FIG. 2), to a substantially transparent state, when this film 5 is powered by the source of electrical energy, as shown in FIG.

Figures 2 and 3 illustrate the case of moderate sunshine of less than 850 W / m ² and a moderate temperature of 20 ° C.

In the case of FIG. 2, the luminosity transmitted through the glazing, represented by the arrow F _t, is equal to approximately 3% of the incident luminosity F ,, given the opacity of the active film 5 and the fact that the glass of leaves 2 and 3 is tinted.

In the case of FIG. 3, the transmitted brightness F _t is equal to approximately 10% of the incident luminosity F ,, given the transparency of the active film 5.

The roof glazing, shown in Figures 2 and 3, therefore does not have the drawbacks mentioned above, concerning the obligation to mount a blackout curtain under the glazing to protect the occupants with respect to solar radiation.

However, the glazing, shown in Figures 2 and 3, has another drawback which is illustrated in Figure 4.

In case of very high temperature, for example greater than 40 ° C and very significant sunshine (greater than 850 W / m ² ), the active film 5 instead of being opaque when it is not powered by the source electric loss of opacity, so much so that the transmitted brightness F _t becomes greater than 3% of the incident light F ,, when the active film 5 is not powered, which is not acceptable to the occupants of the vehicle.

The object of the present invention is to overcome the disadvantages of the glazing above.

This object is achieved, according to the invention, thanks to a motor vehicle glazing comprising two sheets of glass separated by an intermediate layer of transparent plastic material and an active film that can be powered by a source of electrical energy to be able to pass from a substantially opaque state when this film is not supplied to a substantially transparent state, when this film is powered by said source of electrical energy, this glazing being characterized in that it further comprises a passive photochromic layer which is suitable to darken when the sun exceeds a predetermined threshold and causes the reduction of the opacity of the glazing. The photochromic passive layer integrated into the glazing unit according to the invention thus compensates for the reduction in the opacity of the active film when it is not electrically powered and the sunshine is very strong, for example greater than 850 W / m ^2. .

In the preferred application of the invention, the glazing is constituted by a glazing roof or roof of a motor vehicle.

In this application, the glazing according to the invention effectively protects and ensures a well being to the occupants of the vehicle, even in case of high heat and strong sunshine and without the need to equip the glazing with a curtain occultation bulky and expensive.

Preferably, said opaque or transparent active film is embedded in the transparent plastic layer.

However, said opaque or transparent active film may also be located at the interface between one of the glass sheets and the plastic layer.

This active film may be composed of liquid crystals comprising molecules whose electric dipoles can be oriented by virtue of the electric field created by the electric current supplied by said source.

In an advantageous embodiment of the invention, the passive photochromic layer is deposited on the face of one of the glass sheets adjacent to the intermediate layer of plastics material.

However, the photochromic layer may be deposited on the face of the glass sheet intended to be directed towards the inside of the vehicle.

In another embodiment, the photochromic passive layer consists of photochromic compound pigments embedded in the plastic interlayer or in the opaque or transparent active film.

According to another aspect, the invention also relates to a motor vehicle equipped with a glazing unit according to the invention.

This glazing has in particular the advantage of being devoid of blackout curtain, because of the opacity that is provided by the photochromic layer in case of strong sunlight.

Other features and advantages of the invention will become apparent throughout the description below.

In the accompanying drawings, given by way of nonlimiting examples: FIG. 5 is a partial cross-sectional view of a glazing unit according to the invention in which the active film is not electrically powered and is opaque, the photochromic layer being transparent,

FIG. 6 is a view similar to FIG. 5 showing the active film electrically powered and transparent, the photochromic layer being transparent,

FIG. 7 is a view analogous to FIGS. 5 to 6, showing the unpowered active film having lost its opacity and the photochromic layer having become opaque due to strong sunlight,

- Figure 8 is a diagram showing the evolution of the light transmission through the glazing according to the invention, as a function of the power per m ² of sunshine for different power states of the active film.

Figures 5 to 7 show a roof glazing or roof of a motor vehicle comprising, as in the case of Figures 2 to 4, two sheets of glass 2, 3 tinted, separated by one or more layers of transparent plastic material 4 for example in PVB. If necessary, these PVB sheets may have anti-infrared or anti-ultraviolet properties.

The glass sheet 3 adjacent to the passenger compartment of the vehicle may comprise at its periphery an opaque serigraphy 7, as in the case of Figures 2 to 4.

The glazing further comprises an active film 5, which in the example shown is embedded in the intermediate layer of plastic material 4.

This active film 5 may be electrically powered by a source, such as the vehicle battery, in order to be able to pass from a substantially opaque state, as shown in FIG. 5, when the film 5 is not powered, to a state substantially transparent, when the film is powered by the source of electrical energy, as shown in Figure 6.

The roof glazing, shown in FIGS. 5 to 7, comprises, in accordance with the invention, a photochromic passive layer 8 which can darken when the sunlight exceeds a certain threshold, as shown in FIG.

When the power per m ² of sunshine exceeds 850 W / m ² , the active film 5 partially loses its opacity (see Figure 7), as in the case of known glazing. However, this loss of opacity of the film 5 is compensated by the darkening of the photochromic layer 8 which has been added to the glazing according to the invention.

The opaque or transparent active film 5 may be embedded in the plastic layer 4, as shown in FIGS. 5 to 7, or may be located at the interface between one of the glass sheets 2 or 3 and the plastic material.

The active film 5 may be composed of liquid crystals consisting of molecules whose electric dipoles can be oriented in the same direction by virtue of an electric field created by the electric current which supplies the film 5.

When the dipoles are oriented by the electric field, the film 5 is transparent, whereas when these dipoles are not oriented, the film 5 is opaque.

The passive photochromic layer 8 is preferably deposited on the face of one of the two glass sheets 2, 3 adjacent to the intermediate layer of plastic material 4, or on the inner face of the inner glass, or on a sheet of PVB or on the active film, or in a PVB sheet or in the active film.

In the example shown in Figures 5 to 7, the photochromic layer 8 is deposited on the inner face of the glass sheet 3 directed towards the passenger compartment of the vehicle.

This passive photochromic layer 8 may also consist of pigments of photochromic compounds embedded in the plastic of the intermediate layer 4 or in the active film 5 opaque or transparent.

We will now explain in detail the operation of the roof glazing that has just been described.

In the case of Figure 5, the atmospheric conditions are as follows:

- the sunshine is moderate (less than 850 W / m ² );

- the temperature is moderate (20 ° C).

The active film 5 is not powered, as shown in Figure 5, it is therefore opaque.

The photochromic layer 8 is transparent.

The transmitted brightness F _t through the glazing is equal to only 3% of the incident light F ,. In the case of FIG. 6, the atmospheric conditions are the same as in the case of FIG. 5, namely:

- the sunshine is moderate (less than 850 W / m ² );

- the temperature is moderate (20 ° C).

The active film 5 is fed and becomes transparent.

The photochromic layer is also transparent.

The transmitted brightness F _t is equal to 10% of the incident light F ,.

In the case of Figure 7, the atmospheric conditions are as follows:

- the sunshine is strong (higher than 850 W / m ² );

- the temperature is high (over 40 ° C).

Active film 5 is not electrically powered.

However, instead of being opaque, this film 5 undergoes a loss of opacity and passes light.

However, the photochromic layer 8 becomes opaque due to the strong sunlight of the glazing and thus compensates for the loss of opacity of the active film 5.

Therefore, the transmitted brightness F _t is equal to 3%, as in the case of Figure 5, which ensures excellent comfort to the occupants of the vehicle.

The diagram of FIG. 8 represents various curves showing the evolution of the light transmission F _t through the glazing according to the invention as a function of the sun exposure E.

The curve Ci shows that when the active film 5 is not powered, the light transmission F _t remains at 3% up to a sunshine threshold E equal to 850 W / m ² .

Beyond this threshold, the transmitted brightness F _t increases when the photochromic layer 8 is absent.

When this layer 8 is present, the curve C ₂ shows that the transmitted brightness remains equal to 3% even beyond the threshold of 850 K / m ² .

The dotted curve C ₃ shows the contribution of the photochromic layer 8.

The curve C ₄ shows that when the active film 5 is fed and the photochromic layer 8 is absent, the light transmission F _t remains equal to 10% beyond the sunshine threshold equal to 850 W / m ² . When the photochromic layer 8 is present, the curve C ₅ shows that the glazing according to the invention undergoes a slight loss of opacity, when the irradiation is greater than 850 W / m ² .

However, the amount of light received is perceived as identical by the occupants of the vehicle.

Thus, the combination of the active film 5 and the photochromic layer 8 ensures that the opacity of the glazing according to the invention is no longer variable as a function of the power of the sun.

Claims

1. Motor vehicle glazing comprising two glass sheets (2, 3) separated by an intermediate layer of transparent plastic material (4) and an active film (5) which can be powered by a source of electrical energy in order to be able to pass from a state substantially opaque, when this film is not fed to a substantially transparent state, when this film (5) is powered by said source of electrical energy, this glazing being characterized in that it further comprises a passive photochromic layer ( 8) which is able to darken when the sun exceeds a predetermined threshold and causes the reduction of the opacity of the glazing.

2. Glazing according to claim 1, characterized in that it consists of a roof glazing or roof of a motor vehicle.

3. Glazing according to one of claims 1 or 2, characterized in that said active film opaque or transparent (5) is embedded in the transparent plastic layer (4).

4. Glazing according to one of claims 1 or 2, characterized in that said active film opaque or transparent (5) is located at the interface between one of the glass sheets (2, 3) and the layer of material plastic (4).

5. Glazing according to one of claims 1 to 4, characterized in that the active film (5) is composed of liquid crystals comprising molecules whose electric dipoles can be oriented by the electric field created by the electric current supplied by said source.

6. Glazing according to one of claims 1 to 5, characterized in that the passive photochromic layer (8) is deposited on the face of one of the glass sheets (2, 3) adjacent to the intermediate layer of plastic material (4).

7. Glazing according to claim 6, characterized in that the photochromic layer (8) is deposited on the face of the glass sheet (3) intended to be directed towards the inside of the vehicle.

8. Glazing according to one of claims 1 to 5, characterized in that the passive photochromic layer (8) consists of photochromic compound pigments embedded in the intermediate layer of plastic material (4) or in the opaque or transparent active film. (5).

9. Motor vehicle equipped with a glazing unit according to one of claims 8.

10. Motor vehicle equipped with a glazing according to one of claims 8 and without obscuration curtain.