EA032442B1 - Panel emitting light radiation - Google Patents

Abstract

The invention relates to a transparent lighting device (100), with light-emitting diodes (140), comprising first and second glass panels (110), the first (111) and third (121) surfaces of which are at least partially covered with light-emitting diodes (140), said glass panels being spaced apart by means of a spacer (130). According to the invention, such a lighting device comprises diodes arranged on at least one portion of the second (112) and third (121) surfaces of the glass panels, said light-emitting diodes being separated on the same line by a pitch of at least 50 mm. Furthermore, the first (110) and second (120) glass panels are spaced apart from one another by a distance of at least 2 mm.

Description

The invention relates to a transparent lighting device (100) with light emitting diodes (140), comprising first and second glazing (110), first (111) and third (121) front faces of which are at least partially coated with light emitting diodes (140), while these glazings are located at a distance from each other using spacers (130). In accordance with the invention, such a lighting device comprises diodes located on at least one part of the second (112) and third (121) front sides of the glazing, wherein said light emitting diodes are separated on the same line by a gap of at least 50 mm. In addition, the first (110) and second (120) glazings are spaced at least 2 mm apart.

032442 Β1

1. Field of invention

The invention relates to a transparent lighting device. In particular, the invention relates to a transparent backlight device based on light emitting diodes.

The invention can be used, in particular, in information boards with backlighting, signs or other similar means of disseminating information.

2. Solutions known in the art

Information boards and, in particular, street information equipment have become a means of transmitting information, highly valued by advertisers, as they make it possible to demonstrate an advertising campaign in city centers, in areas where advertising is usually limited. Outdoor equipment usually takes the form of a scoreboard of 1.20 m by 1.76 m, i.e. an area of about 2 m ² , and is mainly used for displaying advertisements and / or municipal information.

The outdoor information equipment known from the prior art is usually equipped with a housing enclosing an advertising and / or information poster, with an indoor lighting system and with diffusing material, for example, of the type of white extruded PMMA to which the poster is attached. The lighting system used often takes the form of fluorescent or neon lamps passing through the housing of street information equipment. For example, document PK.2882609 describes an information board in which posters are backlit by neon lamps. This lighting system demonstrates the disadvantage that is characterized by excessive energy consumption, a large thickness of street information equipment, in which, in particular, it is necessary to take into account the diameter of neon lamps. Moreover, the light emitted by this lighting system is not uniform throughout the advertisement or information poster. Finally, the use of such dispersing material as PMMA leads to high maintenance costs associated with its regular replacement.

Therefore, in document AO 2008037450, in order to circumvent the use of neon lamps, they dealt with the backlighting of the posters by means of light emitting diodes (LEE). However, such an arrangement of LEO. as the scheme described in this document does not allow uniformly and optimally to carry out the backlighting of posters when the latter are placed on each side of the lighting device.

3. Objectives of the invention

The aim of the present invention, in particular, is to eliminate these disadvantages, known from the prior art.

In particular, it is an object of the invention in at least one of its embodiments to provide a lighting device, in particular a backlight device, also called a light box, which is transparent from at least one of its front sides.

Another objective of the invention in at least one of its embodiments is the implementation of such a lighting device in a bulletin board and, in particular, in a tool in the form of street information equipment.

Another objective of the invention in at least one of its embodiments is the creation of a bulletin board and, in particular, means in the form of street information equipment that does not require the presence of dispersive material of the type PMMA.

The invention, in at least one of its embodiments, has the additional goal of reducing energy consumption associated with lighting advertising and / or information posters contained in a bulletin board and, in particular, in a tool in the form of street information equipment.

The invention, in at least one of its embodiments, has the additional goal of reducing the cost of maintaining such street information equipment.

The invention in at least one of its embodiments has the additional goal of reducing the thickness of such street information equipment.

4. The invention

In accordance with one specific embodiments, the invention relates to a transparent lighting device with light emitting diodes, comprising:

first glazing with first and second front sides;

second glazing with the main front side opposite the second front side, called the third front side, and another, opposite the main front side, called the fourth front side;

a spacer holding the first and second glazing (110, 120) at a certain distance from each other and defining the internal space between the second and third front sides;

many light emitting diodes.

In accordance with the invention, the lighting device comprises diodes located on at least one part of the second and third front sides of the glazing, wherein said light emitting diodes are separated on the same line by a gap of at least 50 mm, and each of said first and second glazing (110, 120) is electrically conductive.

- 1 032442

The lighting device in accordance with the invention further comprises first and second glazing spaced from each other at a distance of at least 2 mm. The distance separating the two glazing, in particular, is determined by the size of the light emitting diodes and / or the thickness of the intermediate layers of plastic nature, such as, for example, polyvinyl butyral (RUB) or ethyl vinyl acetate (EUA) films, in the case of laminated glass.

In accordance with one particular embodiment of the invention, the light emitting diodes are spaced apart from each other by a gap of 50 to 200 mm. Preferably, the gap between the light emitting diodes (or the distance between the diodes) is from 50 to 110 mm.

In accordance with another specific embodiment of the invention, the distance between the first and second glazings is from 2 to 150 mm.

In accordance with one preferred embodiment of the invention, the diodes present on the second front side are offset from the diodes present on the third front side of the glazing, so that the light emission of the diodes present on the second front side through the second glazing is not impeded by the presence of diodes, present on the third front side.

Preferably, the light emitting diodes present on at least one part of the second front side are offset by half the gap in at least one direction relative to the light emitting diodes (140) present on at least one part of the third front side (121) and placed on a line opposite.

Preferably, then the diodes present on the third front side are offset by half the gap in two directions (i.e., along the X and ос axes) relative to the light emitting diodes present on the line opposite the second front side.

The general principle of the invention is based on the implementation of light emitting diodes on at least one part of the inner faces of the lighting device in order to illuminate both sides of this device. The specific arrangement of the light emitting diodes in a checkerboard pattern and with an offset on the inner front sides of the device makes it possible to backlight in a uniform manner on each side of the device. Moreover, the distribution of light emitting diodes, as well as the distance between the two glazings, makes it possible to create more significant illuminating surfaces.

Thus, the inventors have shown that this particular arrangement of light emitting diodes makes it possible to direct the light flux from the inside of the device to the outside without negative interference with the light flux emanating from the light emitting diodes located on the opposite front side.

This particular arrangement of light emitting diodes, as well as the distance between the first and second glazing, makes it possible to reduce the thickness of the device and reduce energy consumption. The lighting device in accordance with the invention exhibits several special characteristics designed to enable uniform illumination without shaded areas, thus acting on each side of each glazing.

According to one particular embodiment of the invention, the gap between the light emitting diodes is between 50 and 110 mm, and the first and second glazings are spaced at least 2 mm apart.

Thus, this particular distance between the light emitting diodes makes it possible to improve the uniformity of the light emitted by the light emitting diodes, and avoids the point effect of the light emitting diodes.

In accordance with one of the embodiments in accordance with the invention, the distance between the first and second glazings is from 2 to 150 mm.

Thus, the thickness of the lighting device is reduced, thus making it possible to use it as a transparent lighting device or box with backlight, for example, for a poster.

This configuration of the transparent lighting device makes it possible to supply the light necessary, in particular, for uniform projection of light, for example, on posters, placards, photographs in a limited space.

In the present invention, the term light emitting diode or diode is intended to mean a usually inorganic, quasi-point source, typically based on a semiconductor chip, wherein the source differs from ΟΕΕΌ (organic diode) in that it provides an extensive illuminating surface.

The lighting device in accordance with the invention is equipped with connectors or contact points for connecting the respective circuits. Thus, in accordance with one specific embodiment of the invention, the light emitting diodes are directly connected to the connection circuits on at least one part of the second and third front sides of the glazing.

In accordance with one specific embodiment of the invention, the lighting device

- 2 032442 the structure contains the first and second glazing, wherein said glazing is glass, for example, with a transparent conductive layer showing the insulation strips obtained by ablation of the conductive strips by scanning with a laser beam or by metal wires with a diameter of less than 500 μm, or by printing (screen printing) conductive tracks with a width of less than 500 microns.

Preferably, the interior is hermetically sealed first and second glazings and a spacer, whereby dust can not be penetrated between the glazings.

The invention also relates to a method for manufacturing a transparent lighting device, such as described above.

The manufacture of a transparent lighting device includes the following steps:

applying at least partially a coating to at least one part of the second and third faces of the glazing using an electrically conductive coating, wherein the conductive coating comprises at least one set of a metal layer and, if necessary, an insulating layer, the metal layer and insulating a layer is located between the second and third faces;

the location of at least one electronic component on the second and third front sides, while the electronic component contains at least one terminal electrically connected to a conductive coating;

attaching light emitting diodes to at least one part of a second face of the first glazing;

attaching light-emitting diodes to the third front side of the second glazing with offset relative to the light-emitting diodes placed on at least one part of the second front side of the first glazing;

attaching spacers around the perimeter of the lighting device to keep the first and second glazings located at a distance from each other.

It should be understood that it is equally possible to start by applying an electrically conductive coating to the second or third front side or by depositing the coating simultaneously on the second and third front sides. The term metal layer is intended to mean a single layer or set of metal layers.

In accordance with one specific embodiment of the invention, the second and third front sides of the glazing exhibit light emitting diodes on at least one part of their surface. Then the diodes present on the third front side are offset by half the gap with respect to the light emitting diodes present on the line opposite the second front side.

Preferably, then the diodes present on the third front side are offset by half the gap in two directions (i.e., along the X and ос axes) relative to the light emitting diodes present on the line opposite the second front side.

The advantages of this method are the same as the advantages of a transparent lighting device, and they will not be more fully described in detail.

The invention also relates to a placard comprising a lighting device, such as the device described above, and at least one poster-supporting device (eg, mounting rails or slats), configured to fasten at least one poster in front of at least one of the first and the fourth front sides. The placard may further comprise said poster located opposite said at least one of the first and fourth front sides.

The use of such a lighting device as the device described above makes it possible to illuminate a poster located in front of a transparent lighting device, also called a light box. The use of such a lighting device, such as the device described above, for lighting posters makes it possible to noticeably reduce the thickness of the information board, reduce power consumption and reduce the maintenance of information boards.

In accordance with one specific embodiment of the invention, the poster is located at least 5 mm from the first and / or fourth front side of the glazing. Preferably, the poster is located at a distance of 10 to 30 mm from the first and / or fourth front side of the glazing. This minimum distance that must be observed makes it possible to obtain uniform light without shaded areas over the entire surface of the poster and, at the same time, reduce the thickness of the information board.

It should be understood that in a typical case, when a single poster is required to have a backlight, the poster can be placed in front of the first or fourth front side of the glazing of the device.

The placard may include a housing comprising two main front sides and delimiting a hollow interior space, wherein at least one of the main front sides comprises at least one transparent part, wherein a transparent lighting device is enclosed in the housing, and said poster supporting device is configured for location

- 3 032442 indicated at least one poster in the interior of the housing between the specified transparent part of the housing and the lighting device.

In accordance with one specific embodiment of the invention, the information board comprises a poster placed on two opposite front sides of the housing between the lighting device and the inner front side of the housing.

Thus, two posters can be supported by a bulletin board and provided with backlighting through a single lighting device.

In accordance with one specific embodiment of the invention, the transparent portion is at least formed from shatterproof glass. The term shatterproof glass is intended to mean tempered glass or laminated glass.

This type of glass helps protect people from the risk of injury if the glass breaks.

5. Brief description of figures

Other features and advantages of the invention will become more apparent after reading the description of one preferred embodiment below, given as a simple and non-limiting illustrative example, and after reading the accompanying drawings, in which FIG. 1 is an image of a lighting device in accordance with the invention;

in FIG. 2 illustrates a bulletin board comprising a lighting device in accordance with the invention;

in FIG. 3 shows a staggered arrangement of light emitting diodes;

in FIG. 4 is a public display panel established on the basis of.

6. Description of at least one embodiment of the invention

One embodiment of a lighting device in accordance with the invention is presented with reference to FIG. one.

The following description relates to a transparent lighting device 100 comprising a first 110 and a second 120 glazing comprising a plurality of light emitting diodes 140, or BEU. distributed on the second (112) and third (121) front sides.

In particular, the lighting device in accordance with the invention comprises first glazing 110, in particular flat, preferably made of mineral glass or organic glass, with first 111 and second 112 front sides, said front side 112 being covered with a plurality of light emitting diodes, in particular BEU 140, staggered and separated from each other by a gap of 50 to 200 mm, as shown in FIG. 3. Preferably, the distance between the BEU, commonly referred to as the gap, is from 50 to 110 mm, and even more preferably from 70 to 100 mm.

The lighting device in accordance with the invention further comprises a second glazing 120, in particular flat, preferably made of mineral glass or organic glass, with third 121 and fourth 122 front sides, said front side 121 being covered with a plurality of light emitting diodes, in particular BEU 140, staggered and separated from each other by a gap of from 50 to 200 mm, preferably from 50 to 110 mm, even more preferably from 70 to 100 mm, while the BEUs are located opposite in BEB placed on the front side 112, and offset by half the gap relative thereto.

In accordance with the invention, the front sides 112 and 121 contain electronic circuits that make it possible to supply power to the BEU 140, defined in the conductive layer previously deposited on the front sides 112 and 121, by burning a part of the conductive layer with a laser. The conductive layer can also be deposited using photolithography or else using printing etching methods. Therefore, this contact element enables independent power supply (current and / or voltage) of each of the glazing. In order to obtain a good electrical contact for each circuit that requires power, separate unipolar conductive elements can be used (if necessary with conductive glue or self-adhesive material on top). Electronic circuits can be obtained by coating at least partially on at least one part of the second 112 or third 121 front side using an electrically conductive coating, wherein the conductive coating comprises at least one set of a metal layer and, if necessary, an insulating layer, a metal layer is located between the second 112 or third 121 front side and the insulating layer. Then, at least one electronic component is arranged on the second 112 and / or third 121 front side, wherein the electronic component contains at least one terminal electrically connected to the conductive coating. The presence or absence of an insulating layer is determined, in particular, by the deposition method of the metal layer, namely by pyrolytic deposition or by SMS (chemical vapor deposition). For example, if the metal layer is deposited pyrolytically (the so-called hard layer), then the insulating layer is not necessary, whereas if the metal layer is deposited by SMS (the so-called soft layer),

- 4 032442 then an insulating layer is required.

Preferably, the LEE 140 is attached to at least one portion of the faces 112 and 121 by means of a conductive adhesive. The conductive zones supplying power to ΕΕΌ are connected to power strips (busbars). Advantageously, these busbars are arranged on at least one facet of the glazing so that they can be hidden by a frame covering the facet of the glazing and containing power cables for the busbars. In accordance with one feature, light emitting diodes can be encapsulated, that is, contain a semiconductor chip and a sheath, for example an epoxy resin or PMMA type resin encapsulating a crystal. This shell can perform many functions: providing protection against oxidation and moisture, etc. Diodes 140 can be enclosed in a shell of a well-known protective substance to ensure tightness against water, dust, etc.

The diode 140 may be, for example, a semiconductor chip of a size of the order of several hundred microns or nm, and if necessary with a miniature capsule, for example, for protection.

Preferably, the diodes can be simple chips with a small capsule, in particular those of type 8 тип (surface mount device). The diode may preferably be a light emitting diode of medium power, that is, greater than 0.1 W, or with a brightness greater than or equal to 8 lm;

a light emitting diode of high power, that is, greater than or equal to 1 W, or with a brightness greater than or equal to 80 lm.

The light emitting diode may preferably have a light output of at least 40 lm / W or even at least 60 lm / W.

Lighting may be, in particular, lighting in accordance with a total light output of at least 40 lm / W. The first and second glazing, the second 112 and third 121 front sides of which are covered with at least some 60-watt LIE 140, for example, of type Ν82Α150ΑΤ of ΝΙΟΗΙΑ or type Ν82Α150Α-Ε of представлены, are shown in FIG. one.

LEE are fed either through thin conductive strips 400 nm thick and a little less than 55 mm wide covering the glazing surface, or through metal wires whose diameter does not exceed 300 microns. They create a luminous flux, covering the visible spectrum and passing through transparent glazing, in order, for example, to illuminate the poster.

The first 110 and second glazing 120 are connected to one another by means of a spacer 130, sealed or non-tight, and separated by an internal space 131, wherein said glazing is separated by a distance of 35 to 150 mm, preferably a distance of 45 to 110 mm. Said spacer 130 may be a profiled element. Spacers used for several glazings are usually a hollow metal profile, stamped or molded, or made of organic matter, etc., a profiled element with mounting brackets or a profiled element bent at the corners, in this case the spacer consists of a continuous profile element bent at the corners. The spacer inside the insulating glazing with its side faces is bonded to the inner faces of the glass sheets with butyl rubber, the role of which is to make the inner part of the glazing leakproof with respect to water vapor. The spacer is positioned with a recess inward of the glazing and close to the faces of said glazing 110 and 120, in order to create a perimeter groove into which sealing agents such as mastics, such as polysulfide or polyurethane, are injected. Mastic strengthens the mechanical structure of the two glazings and provides tightness against liquid water and solvents. It should be understood that you can use any means that can provide the role of the strut. A spacer 130 may be provided that does not finally fasten the first and second glazing to each other. Thus, the first 110 and second 120 glazing can be easily separated in order to be able to replace, for example, a defective light-emitting diode 140. It should be understood that in the case of laminated glazing, when the first and second glazings are separated by insert films, usually of a plastic nature, related to the type of RUV or EUL. the presence of a spacer is not necessary. Two glazings are held together by lamination.

Second glazing 120 combines light emitting diodes 140 (LEC), as, for example, in FIG. 1 (or in FIG. 3) (where a sectional view of a lighting device is shown). LEE are located on at least one part of the third 121 front side of the glazing staggered and offset by half the gap relative to LIE 140, placed on the line opposite on at least one part of the second 112 front side of the glazing.

The term staggered is intended to indicate the periodically repeating arrangement of light emitting diodes (or LEE) line by line, with the diodes being separated by a distance a, called the gap, and each second line is offset by half the gap ά relative to the line preceding or following it. Each line is half a gap ά from the line preceding it and / or following it. It should be understood that ά is equivalent

- 5,032,442 half the distance a.

It should be understood that the term glass is intended to mean glasses of all types and equivalent transparent materials, such as mineral glasses and organic glasses. Mineral glass may equally consist of glasses of one or more known types, such as sodium-calcium-silicate glasses, borate glasses, as well as crystalline and semi-crystalline glasses. Organic glass may be a rigid thermoplastic or thermoset transparent polymer or copolymer, such as, for example, transparent synthetic polycarbonate, polyester or polyvinyl resin. Glazing 110 and 120 preferably have the same or identical geometrical dimensions, the same nature and the same shape (rectangular, square, etc.) and, if necessary, have curvature. The first 110 and the second 120 glazing can be made of transparent or even ultra-transparent glass, or frosted glass. Preferably, the first 110 and second glazing 120 exhibit an Lt (light transmission) value of 70 to 98% and a thickness of 1 to 50 mm. The thickness may vary at different points on the surface of the glazing. The surface may be flat or curved. However, flat glazing with a constant thickness at each point is preferred.

In accordance with another embodiment of a transparent lighting device in accordance with the invention, at least one method of ensuring the scattering of at least one part of the light radiation is applied to the first 110 and second 120 glazing. This scattering method may be selected from matting the glazing surface, sandblasting the glazing, or printing relief. Matting can be provided, for example, by means of an aqueous solution of hydrofluoric acid.

In FIG. 1 shows the first 110 and second 120 glazing of transparent glass, belonging to the type P1ap1e1 O from VOC, with a geometric size of 1175 mm in length and 1721 mm in width with a thickness of 4 or 6 mm.

On one or both faces, functional coatings of the type of non-scratch anti-reflective coating can be used.

A lighting device in accordance with the invention, in particular, is manufactured using the following steps:

cutting to a size (for example, 1721 mm x 1175 mm) of the first glazing 110 (or the first glass substrate) coated with a transparent electrically conductive layer, for example glazing of the type P1a1Be1 O, supplied to the market by LOS O1a8 Eigore;

subsequent thermal hardening of the glazing;

fabrication of a power supply circuit for ΕΕΌ 140 (or a conductive structure) by selectively acting in the form of lines on the conductive layer (or structuring the conductive layer) by, for example, a laser beam that locally burns out the conductive layer to create insulating lines, for example, several hundred microns thick;

deposition and attachment (for example, using conductive glue) ΕΕΌ 140, for example, using an automatic machine of the Ryuk & P1ace type (such as the machine described in patent application No. AO 2009100769 A1), in accordance with the layout shown in FIG. 3, on the second 112 and third 121 front sides of the first and second glazing, carrying the power supply circuit for ΕΕΌ 140, while the positive electrode (or positive contact pad) and the negative electrode (or negative contact pad) ΕΕΌ 140 are respectively glued to the positive and negative electrodes (or positive and negative conductive areas) made on the power supply circuit for ΕΕΌ 140;

application of connection technologies (for example, for the anode on the left, and for the cathode on the right) to be able to connect the device to an external power source;

polymerization of conductive glue in a furnace;

joining the first 110 and the second 120 glazing by means of a spacer 130.

A lighting device in accordance with the invention can generate signal lighting, decorative lighting, as well as architectural lighting.

The lighting device in accordance with the invention can be intended, in particular, for a backlight information board or, in particular, for means in the form of street information equipment.

In FIG. 2 illustrates a backlit placard 200 comprising a housing 210 defining a hollow interior 211 and showing at least one transparent portion 212 on at least one of its main front faces;

a transparent lighting device 100 in accordance with the invention; and two posters 213, each of which is located in the interior of the housing between the inner wall 214 of the housing 210 and the lighting device 100 and opposite the transparent part 212, so that it is visible to people.

Poster 213 is located at a distance of at least 5 mm, and preferably at least 10 mm, from the first 111 and fourth 122 front sides of the glazing of the lighting device. Preferably,

- 6 032442 poster 213 is located at a distance of 10 to 30 mm to reduce the effect of shading caused by the light emitted by LIE 140 on the poster 213.

Thus, the poster 213 can be illuminated with a uniform light at a lower cost. Moreover, the use of LEI 140 as a means of illuminating the poster makes it possible to significantly reduce the frequency of maintenance of information boards, as well as reducing energy consumption.

In addition to greatly reducing, or even not having, a blinding effect, the invention can also provide one or more of the following advantages:

improved distribution of radiation density over the entire surface of the poster;

the ability to reduce the number of light emitting components;

simplification of the power supply system of components;

improving the aesthetics of the information board.

Finally, the use of the lighting device 100 in accordance with the invention for backlighting posters located on both sides of the device makes it possible to significantly reduce the thickness of the information boards. Indeed, a placard 200 in accordance with the invention may, for example, have a size of 126 mm in thickness versus 190 mm or even 205 mm for placards that traditionally use fluorescent or neon lamps passing through the housing of street information equipment.

According to the invention, the transparent lighting device 100 is attached to the housing 210 by means capable of securing the lighting device to the information display housing.

The housing 210 rests, for example, on a foundation fixed to the ground on a public road or in some other public place, as shown in FIG. 4. The housing 210 delimits a hollow interior space 211 and exhibits at least one opening on at least one of its main front sides, the opening being typically damped by a transparent window glass 212. The transparent window glass 212 used to enclose the opening preferably represents safety glass from 8 to 10 mm thick, i.e. thermally toughened glass or laminated glass. This type of glass helps protect people from the risk of injury if the glass breaks.

In accordance with a specific embodiment of the invention, the poster is placed at a distance of 5 to 30 mm from the opening of the housing.

In the interior of the housing 211 is a device for displaying posters, containing, for example, a strip containing posters to be displayed in series in front of the opening of the housing behind the window pane. In particular, the strip can be wound on two rollers, the upper and lower, respectively, controlled by at least one electric motor. Of course, the placard may contain a single poster, mounted on a window pane.

Of course, the present invention is not limited to the above embodiments, given as examples.

In particular, a person skilled in the art will be able to implement any variant of the form of an information board, the color of light-emitting diodes, their individual addressing to reduce power consumption or create animations, etc.

Similarly, the present invention is not limited to a rectangular lighting device.

The invention is also applicable generally to the field of lighting (and therefore, to applications other than poster backlighting).

Claims (12)

CLAIM 1. A transparent lighting device comprising a first electrically conductive glazing (110) with first and second major surfaces (111, 112); a second electrically conductive glazing (120) with a third and fourth major surfaces (121, 122), wherein the first electrically conductive glazing (110) and the second electrically conductive glazing (120) are parallel to each other, and the second main surface (112) of the first glazing (110) and the third main surface (121) of the second glazing (120) facing one another; a spacer (130) holding the first electrically conductive glazing (110) and the second electrically conductive glazing (120) at a distance of at least 2 mm; light emitting diodes (140) mounted on at least one part of the second main surface (112) and at least one part of the third main surface (121), while the distance between the light emitting diodes (140) located on one straight line is constant and equal to at least 50 mm, and the light emitting diodes (140) mounted on the second main surface (112) are offset from the light emitting diodes mounted on the third main surface (121) so that the light emitting through the second glazing (120) eniyu of light emitting diodes (140) mounted on the second major surface (112) does not prevent the - 7 032442 the presence of light emitting diodes (140), mounted on the third main surface (121). 2. The device according to claim 1, in which the light-emitting diodes (140), mounted on the second main surface (112), are biased in one direction relative to the light-emitting diodes (140), mounted on the third main surface (121), the offset being half the distance between nearby light emitting diodes (140) mounted on the third main surface (121). 3. The device according to claim 1, in which the light emitting diodes (140) mounted on the second main surface (112) are biased in two perpendicular directions relative to the light emitting diodes (140) mounted on the third main surface (121), wherein each direction is equal to half the distance between the adjacent LEDs (140) mounted on the third main surface (121). 4. The device according to any one of the preceding paragraphs, in which at least one of the first and second electrically conductive glazing (110, 120) comprises sheet glass on which a transparent electrically conductive circuit is made to which light-emitting diodes (140) are connected. 5. The device according to any one of the preceding paragraphs, in which the spacer (130), the first electrically conductive glazing (110) and the second electrically conductive glazing (120) form a hermetically closed inner space. 6. The device according to any one of the preceding paragraphs, in which the distance between the first electrically conductive glazing (110) and the second electrically conductive glazing (120) is not more than 150 mm. 7. The device according to any one of the preceding paragraphs, in which the distance between the light emitting diodes (140) located on one straight line is not more than 200 mm. 8. A bulletin board containing a transparent lighting device according to any one of the preceding paragraphs. 1-7 and at least one device for placing a poster or posters opposite at least one of the first and fourth main surfaces (111, 122). 9. The panel of claim 8, further comprising a housing (210) with at least one transparent part (212) located opposite one of the first and fourth main surfaces (111, 122), while the housing (210) limits the internal space for placing in it a transparent lighting device and a device for placing a poster or posters between one of the first and fourth main surfaces (111, 122) and at least one transparent part (212) of the housing (210). 10. The panel according to claim 9, in which the transparent part (212) of the housing (210) is a shatterproof glass sheet. 11. A panel according to any one of the preceding paragraphs, in which the device for placing a poster or posters made with the possibility of placing a poster or posters (213) relative to one of the first and fourth main surfaces (111, 122) at a distance equal to at least 10 mm . 12. A panel according to any one of the preceding paragraphs, in which the device for placing a poster or posters is arranged to accommodate two posters (213), the first of which is placed opposite the first main surface (111), and the second opposite the fourth main surface (122) . - 8 032442