FR3053630A1 - LIGHT-EMITTING MATERIAL IN SHEET - Google Patents

Abstract

A luminescent sheet material (1) comprises a solar radiation-transparent sheet substrate (2), a phosphorescent layer (3) on a first side of the substrate (2) and a semi-reflective layer (4) metallized on a second side of the substrate (2) opposite to the first face, these layers being designed to allow the solar radiation to illuminate the phosphorescent layer (3) through the metallized semi-reflecting layer (4) and the substrate (2), the semi-reflective layer reflective (4) metallized reflective radiation of phosphorus.

Description

Technical area

The present invention relates to the field of luminescent sheet materials which can serve as a tarpaulin and in particular as a shade cloth.

Prior art

Document CN201103265 describes such a luminescent sheet material which is used to manufacture a protective cover. This material comprises a substrate layer on which is deposited a phosphorescent coating capable of storing light during the day, that is to say by absorbing ultraviolet or visible light from the light spectrum, and of releasing it during the night.

However, with this kind of luminescent sheet material, the light which is released during the night by phosphorescence is diffused on both sides of the sheet.

If the tarpaulin is used to make a tent canvas or a shade fabric for example, part of the light emitted at night by phosphorescence is lost since this light is directed upwards while the area of interest to be lit is down.

Summary of the invention

The object of the invention is therefore to overcome the drawbacks indicated above by proposing a new luminescent sheet material.

To this end, the subject of the invention is a luminescent sheet material, characterized in that it comprises a sheet substrate produced with a textile with translucent to solar radiation, a phosphorescent layer on a first face of the substrate and a semi layer -metallic reflective on a second face of the substrate opposite to the first face, these layers being designed to allow the solar radiation to illuminate the phosphorescent layer through the metallized semi-reflecting layer and the substrate, the metallized semi-reflecting layer reflecting the phosphorus radiation.

The luminescent sheet material according to the invention may have the following particularities:

- The substrate can be a woven or non-woven fabric, for example a fabric of the Mesh type or even of the type of the brand Tyvek or Valeron or even a non-woven sheet known under the name of spunbound;

- the phosphorescent layer is designed to emit radiation in the spectrum of green-yellow;

- the phosphorescent layer has an emission band between 470nm and 590nm, with a peak centered around 520nm;

- the phosphorescent layer is deposited on the first face of the substrate by coating extrusion;

- the semi-reflective layer is covered with a UV protection layer.

The invention extends to a tarpaulin, produced with a luminescent sheet material according to the invention and to a tent or shade fabric, produced with tarpaulin according to the invention.

The basic idea of the invention is to make the luminescent sheet material light up by phosphorescence almost only on one side, which makes it possible to increase the lighting power compared to the state of the prior art indicated above.

The irradiation by solar radiation passing through the metallized semi-reflecting layer and the substrate and transmitted to the phosphorescent layer excites the phosphorus by a phenomenon of trapping of electronic charges linked to the phosphorescence process.

Night luminescence is caused by a phenomenon of trapping of electronic charges.

According to the invention, the semi-reflecting layer has a partially transparent metallized face, which reflects about 90% of the solar radiation and which transmits through the substrate about 10% of the solar radiation to the phosphorescent layer to excite the phosphorus. The semi-reflective layer reflects about 90% of the phosphorescent light emitted by the excited phosphorus towards the phosphorescent layer.

We can choose phosphorus which radiates in a certain spectrum chosen not to attract insects and other arthropods because we know that light in the spectrum of green-yellow tends not to attract insects, as opposed to blue light / UV.

And if the substrate is synthetic mesh film with fine mesh very inexpensive to produce, we can make tarpaulins for humanitarian shelters which are low cost and which are very effective especially in tropical countries, particularly affected by mosquitoes that can transmit diseases such as malaria, dengue, zika.

Brief presentation of the drawings

The present invention will be better understood and other advantages will appear on reading the description which follows and the appended drawings in which:

Figure 1 schematically illustrates a luminescent sheet material according to the invention, the material being packaged in rolls;

Figure 2 schematically illustrates in section the luminescent sheet material according to the invention.

Description of the embodiments

The luminescent material 1 in sheet or film (strip) according to the invention, which is shown in Figure 1 is packaged in a roll.

The width of the roll can be for example 1.5 meters.

As the sheet of the material according to the invention can be very thin, it is possible to have rolls of several hundred meters of strip.

FIG. 2 shows the different layers of the luminescent sheet material 1 according to the invention.

It comprises an intermediate layer forming a sheet substrate 2 which is translucent to solar radiation.

It also comprises a phosphorescent layer 3 placed on a first face of the substrate and a metallized semi-reflecting layer 4 which is placed on the other face, opposite to the substrate 2.

In the case of an application to a tent canvas, the semi-reflective layer 4 is the layer of material which is intended to be on the side outside the tent.

Therefore, it is advantageous to protect this layer 4 against ultraviolet (UV). Thus, reference 5 designates a layer of protection against ultra-violet 3053630.

Layers 4 and 5 are designed to allow solar radiation to illuminate the phosphorescent layer 3 through the metallized semi-reflective layer 4 and the substrate 2 while blocking the radiation of the phosphor from layer 3 through the metallized semireflective layer 4 .

The substrate 2 can be a woven or non-woven fabric, for example a synthetic textile screened in high density polyethylene such as for example Mesh with a grammage of approximately 60 g / m ² and a thickness of approximately 100 μm.

The phosphorescent layer 3 may for example be film prepared from granulated polyethylene and 50% by mass of phosphorus powder doped with Europium. The characteristics of such a phosphorescent layer are for example the following:

Weight: preferably 200g / m ²

Thickness: preferably 130 µm

According to the invention, this phosphorescent layer 3 based on Europium emits light in the spectrum of green-yellow with an emission band between 470nm and 590nm, and with a peak centered around 520nm, and with a width of strip at mid-peak height between 500nm and 540nm.

The phosphorescent layer 3 could be made of another phosphorescent material also emitting in yellow green, or in certain special cases a material emitting in light blue, dark blue, or in red or orange.

The semi-reflective layer 4 is for example a film of polyether terephthalate (polyester or PET) which is metallized on one of its two faces with an optical density of 1.0, thus allowing a transmission of 90% of the light on the side of the face metallic.

The metallized semi-reflective layer 4 can be bonded to the substrate 2 so that it partially passes the solar radiation RS towards the substrate 2 and reflects the majority of the light emitted from the phosphorescent layer 3 through the substrate. 2.

The characteristics of such a semi-reflecting layer 4 are for example the following:

Weight: between 15 and 50g / m ² (grams per square meter), and preferably 17g / m ²

Thickness: between 10 and 30 pm (micrometer), and preferably 12 pm

The protective layer 5 is a film, for example made of polyether terephthalate (PET) treated in a known anti-UV manner.

This protective layer 5 serves as a barrier to solar radiation, for example below 400 nm.

The characteristics of such a UV protection layer 5 are for example the following:

Weight: between 15 and 50g / m ² (grams per square meter), and preferably 28 g / m ²

Thickness: between 10 and 30 pm (micrometer), and preferably 20 pm

The process for manufacturing the luminescent sheet material 1 can be as follows.

The substrate 2 can be a commercial product of the textile type translucent to solar radiation RS.

The phosphorescent layer 3 can be deposited on the first face of the substrate 2 by a known method of coating extrusion with a speed of 10 to 100 meters per minute.

It can also be deposited by coating.

The metallized semi-reflecting layer 4 can be bonded to the second face of the substrate 2, in a known manner using an adhesive having an aliphatic catalyst resistant to ultraviolet, the metallized face of the semi-reflecting layer 4 being on the side opposite to that glued to the substrate 2.

The protective layer 5 can be bonded to the metallized face of the semi-reflecting layer 4, in a known manner using an adhesive having an aliphatic catalyst resistant to ultraviolet light.

The UV protective layer 5 can also serve to reinforce the solidity of the luminescent sheet material.

Provision may be made for the semi-reflective layers 4 and UV protection layers 5 to be combined into a single layer placed on the substrate 2.

According to the invention and as illustrated by the arrows in FIG. 2, the metallized face 4M of the semi-reflecting layer 4 partially transparent reflects about 90% of the solar radiation (arrows RR in solid line) and transmits through the substrate 2 about 10% of solar radiation to the phosphorescent layer 3 to excite the phosphorus. Then, during the luminescence RL emitted at night, the semi-reflecting layer 4 reflects approximately 90% of the phosphorescent light (arrows RLR in dotted lines) emitted by the phosphorus excited towards the phosphorescent layer 3, that is to say towards the interior of the tent, in order to increase the lighting power.

This luminescent sheet material according to the invention can be used for the manufacture of tarpaulin for tent canvas or shade fabric in particular.

With this tarpaulin, you can light up at night in the tent under the shade cloth.

If the phosphorescent layer is well chosen, we can also protect ourselves from insects and other arthropods.

Finally, when the phosphorus emits at night in the green-yellow, that is to say in the wavelengths outside of the blue which is the peak of sensitivity of the glial cells, the circadian cycle of the people present under the tarpaulin is little or not disturbed.

Claims (8)

1. Luminescent sheet material (1), characterized in that it comprises a substrate (2) in sheet translucent to solar radiation, a phosphorescent layer (3) on a first face of said substrate (2) and a semi-reflective layer (4) metallized on a second face of said substrate (2) opposite said first face, these layers being designed to allow solar radiation to illuminate said phosphorescent layer (3) through said metallized semi-reflecting layer (4) and said substrate (2), said metallized semi-reflecting layer (4) reflecting the radiation of phosphorus. 2. Material (1) according to the preceding claim, characterized in that said substrate (2) is a synthetic textile screened in high density polyethylene of the Mesh type. 3. Material (1) according to previous, characterized phosphorescent (3) is radiation in one of the spectrum in that designed for green-yellow. claims said layer issue a 4. Material (1) according to claim 3, characterized in that said phosphorescent layer (3) has an emission band between 470nm and 590nm, with a peak centered around 520nm. 5. Material (1) according to one preceding, characterized in that phosphorescent (3) is filed on claims that said layer said first face of the substrate (2) by coating extrusion or by coating. 6. Material (1) according to one of the preceding claims, characterized in that said semi-reflecting layer (4) is covered with a UV protective layer (5). 7. Tarpaulin, characterized in that it is made with a material (1) according to one of claims Previous 10. 8. Tent or shade fabric, characterized in that it is produced with a tarpaulin according to claim 7. 1/1