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1. WO2007104729 - MIROIR ÉCLAIRANT

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

Illuminating mirror

The present invention relates to a glass illuminating mirror delivering light radiation generated on its perimeter by LEDs in which the density of the radiation is well distributed over an entire illuminating peripheral zone.

An illumination device comprising a transparent glass support panel coated with electrically conducting bands on which light-emitting diodes are mounted, emitting their light through the transparent support, is known (Patent US 6 270 236 Bl) .

However, this known device appears to be a panel formed from a multitude of very bright light spots in line with the light-emitting diodes separated by black or very dark zones. This results in an effect not very conducive to use of the panel in applications for illumination or for decoration.

The invention remedies this drawback by providing an illuminating mirror that is a glass panel comprising a multitude of LEDs generating light radiation, the radiation density of which is well distributed over the entire illuminating surface of the panel.

For this purpose, the invention relates to a mirror emitting light radiation, as defined in Claim 1.

The dependent claims define other possible embodiments of the invention, certain ones of which are preferred.

Apart from the great reduction, if not absence, of the abovementioned dazzling effect, the invention may also provide one or more of the following advantages : • the radiation density is better distributed over the illuminating area of the panel;
• the number of radiation-emitting components may be reduced;
• the power supply system for the components is simplified; and
• a more attractive mirror is obtained.

The light-radiation-emitting mirror according to the invention is composed of at least one glass sheet. The term "glass sheet" is understood to mean any glass plate with a thickness possibly ranging between 1 and 50 mm. The thickness may vary at different points on the surface of the sheet. The surface may be flat or curved. However, flat sheets of glass having the same thickness at every point on the surface are preferred. It does not matter whether the glass consists of one or several types of known glass, such as soda-lime glass, borosilicate glass, crystalline and semicrystalline glass, or opal glass. The colour of the glass may be neutral (transparent or grey glass) or of greater or lesser saturation (bulk-tinted or surface-tinted with a shade that may range from red to violet) . The colour may be uniformly distributed over the entire surface of the sheet or, on the contrary, it may be localized in one or more particular zones of the surface of the panel. Sheets of glass that are uniformly neutral or uniformly coloured over the entire surface or the thickness of the sheet are preferred. The glass of the sheet may also be transparent or, on the contrary, be relatively filtering for light radiation lying below and above the frequencies of the visible spectrum.

The mirror according to the invention is also composed of a plurality of light-emitting diodes (LEDs) that generate light radiation. The term "light radiation" is understood to mean both radiation belonging to the visible spectrum and radiation outside this spectrum. Such radiation may be perfectly monochromatic or, on the contrary, it may be distributed over one or more contiguous or non-contiguous frequency bands. These components may be chosen from various LEDs having optoelectronic properties and from components capable of emitting radiation outside that populating the visible spectrum, but optionally with radiation falling within this spectrum. These are for example LED diodes emitting in the visible spectrum and UV and/or visible and/or IR diodes .

The light radiation generated by the LEDs has a wavelength lying between 200 nm and 1 mm. Preferably, the light radiation is radiation belonging to the visible spectrum. The light radiation may also advantageously include at least part of the visible spectrum and at least part of the infrared and/or ultraviolet spectrum.

According to the invention, the LEDs are placed inside the mirror, that is to say they are placed on a surface internal to the mirror that has no contact with its external environment.

The mirror comprises an assembly of at least one emitting structure with at least one reflecting structure. The term "emitting structure" is understood to mean any structure comprising the glass sheet (s) and the LEDs. The term "reflecting structure" denotes any structure capable of reflecting at least some of the radiation emitted by the emitting structure. The reflection of the emitted radiation may be total or partial, the remainder of the radiation being absorbed by and/or transmitted through the reflecting structure.

Reflecting structures that have a light reflection factor ranging from 35.0 to 99.9% are generally preferred.

Examples of preferred emitting structures are flat glass sheets bearing the LEDs on their surface. The reflecting structure is a metal surface parallel to the emitting structures. The emitting and reflecting structures of the mirror according to the invention are in contact with one another.

According to the invention, the emitting structure is assembled by lamination with the reflecting structure.

In a first preferred embodiment of the mirror according to the invention, the LEDs comprise directional radiation generators. These components are oriented so that the direction of the radiation is perpendicular or close to perpendicular to the surface of the reflecting structure.

In another preferred embodiment of the mirror according to the invention which is compatible with the first embodiment, the reflecting structure is a mirror selected from those comprising a reflecting metal surface. The metal of the reflecting surface is advantageously a film of silver or a silver alloy. The metal film has a thickness that may generally range from 70 to 120 nm.

According to the invention, the laminated assembly that the mirror forms is provided with dispersion means for dispersing the light radiation peripherally. This dispersion means is a sheet of clear glass, the surface of which has been frosted or sandblasted in the peripheral zone, on the external side of the laminated assembly, the side opposite that of the reflecting structure relative to the emitting structure. The frosting may have been carried out for example by means of an aqueous hydrofluoric acid solution.

The term "peripheral zone" is understood to mean a relatively broad zone lying on the border of the mirror surrounding a central zone of the mirror that distinctly reflects the images of objects facing it and in line with which the clear glass is neither frosted nor sandblasted.

In another embodiment of the mirror according to the invention, which is preferred, a sheet of plastic chosen from polyesters is laminated between the glass sheet of the emitting structure, on which the LEDs lie, and the peripherally frosted sheet of clear glass of the dispersion means. The polyester of the plastic is for example chosen from polyvinyl butyral, ethylene/vinyl acetate copolymers and polyethylene terephthalates .

In the latter embodiment, the LEDs are advantageously supplied with electric current by means of a conducting translucent layer deposited on the glass sheet of the emitting structure on which the LEDs lie .

Preferably, zones have been isolated from the rest of the conducting layer by thin isolating bands. These isolating bands may for example be produced by ablating a thin band of conducting layer by sweeping with a laser beam.

The conducting zones supplying the LEDs are connected to busbars. Advantageously, these busbars are located on at least one edge of the mirror so as to be able to be concealed by a frame that covers the edges of the mirror and comprises the power supply cables for the busbars .

An illuminating mirror according to the invention will now be described in detail by means of an example illustrating the invention without however seeking to limit its scope.

Example: Illuminating mirror comprising LEDs

The figure shows a mirror comprising a transparent clear glass sheet (1) 3.15 mm in thickness and a conventional mirror composed of another glass sheet (2) 4 mm in thickness bearing, on one of its faces, a metallic silver film (3) (standard silvering) 70 to 120 nm in thickness. The silver film (3) is protected from corrosion on its external face by two thin layers of suitable paint each about 50 μm in thickness, as in conventional mirrors.

Sandwiched between the two glass sheets is a clear-tinted layer (4) of polyvinyl butyral (PVB) 0.76 mm in thickness. LEDs (5) of the Nichia Warm White® brand and of the NFSL036 type are in contact with the glass sheet (2) and are inserted into the PVB layer (4) at a uniform distance of 55 mm in two dimensions in a peripheral zone (9) of a central reflecting zone (10) of the mirror.

The LEDs (5) are supplied via conducting bands

(8) cut in the conducting layer (6) that covers the surface of the glass (2) . Said LEDs deliver a light flux extending over the visible spectrum and passing through the transparent clear glass sheet (1).

A zone (7) of the clear glass (1) is frosted by hydrofluoric acid over the perimeter of the mirror and covers the LEDs (5) .

The whole assembly comprising the mirror (2, 3), the LEDs (5), the PVB sheet (4) and the transparent glass sheet (1) is mechanically assembled by the forces of adhesion joining the glass sheets (1, 2) to the PVB sheet (4) .