EP3542101B1 - Lighting device comprising a screen with regions having different light transmission coefficients - Google Patents

Description

The invention relates to lighting devices, and more precisely those which comprise a light source delivering photons intended to ensure at least one photometric function.

Here we mean “lighting device” a luminous device capable of providing at least one photometric function of lighting or signaling or of a lighting effect, possibly decorative.

In certain fields, such as for example that of vehicles, possibly of the automobile type, lighting devices are used to produce a light band consisting of an alternation of first light zones and second dark zones. This is for example the case when the lighting device is intended to provide a position light function (or night light or even lantern) and/or a daytime running light function (or DRL (for “Daytime running Light (or Lamp) » - light signaling automatically switched on when the vehicle is put into operation during the day)).

Currently, this type of device comprises a light source (generally at least one light-emitting diode associated with a light guide), a mask placed in front of the light source and comprising through-holes defining the first zones and spaces between through-holes defining the second zones, and a protective glass placed in front of the mask with holes. The mask is made of an opaque plastic material (for example black), and therefore only the photons which pass through the through holes generate clear light in the first zones which are interposed between second opaque zones preventing the passage of photons.

Such an arrangement has several disadvantages. Indeed, it turns out to be relatively bulky following the general direction of propagation of the photons (longitudinal direction in the case of a vehicle) of the made of the presence of a mask and protective glass. Then, he is often subject to condensation between his mask and his protective glass due to the significant temperature differences upstream of the mask and downstream of the protective glass. Furthermore, it does not offer very good light output because some of the photons are prevented from going outside due to the presence of the second opaque zones defined by the mask outside the through holes. In addition, positioning the protective glass in front of the mask is often difficult due to their respective dimensional manufacturing tolerances and their respective clearances. A lighting device according to the state of the art is described in the document JP2006179684 A .

The invention therefore aims in particular to improve the situation.

For this purpose, it proposes in particular a lighting device comprising a light source capable of delivering photons to a predefined location which must ensure at least one photometric function.

This lighting device also comprises a screen placed in front of the predefined location and comprising an alternation of first and second zones respectively having a first light transmission coefficient and a second light transmission coefficient strictly lower than this first light transmission coefficient, of so that the light resulting from the photons passing through each first zone has an intensity strictly greater than the intensity of the light resulting from the photons passing through each second zone.

Thus, we do away with the mask with holes, which makes it possible in particular to reduce the bulk following the general direction of propagation of the photons, and to facilitate the positioning of the screen.

• ➢ la première couleur est une couleur dite cristal blanc transparent et la seconde couleur est noire opaque ;
• ➢ l'écran est une pièce dans laquelle les premières zones sont réalisées dans une première matière plastique ayant la première couleur et les secondes zones sont réalisées dans une seconde matière plastique ayant la seconde couleur ;
  • la pièce comprend des première et seconde sous-parties réalisées respectivement dans les première et seconde matières plastiques. La première sous-partie est solidarisée fixement à une partie au moins d'une face externe de la seconde sous-partie, orientée à l'opposé de l'endroit prédéfini, et la seconde sous-partie comprend des trous traversants définis devant des portions de la première sous-partie qui définissent respectivement les premières zones ;
• ➢ dans un mode de réalisation ne faisant pas partie de l'invention, l'écran peut être une pièce en matière plastique ou en verre ayant la première couleur et comportant une face munie d'éléments rapportés ayant la seconde couleur et définissant les secondes zones ;
  • la source de lumière comprend au moins une diode électroluminescente, éventuellement de type organique ;
• ➢ la source de lumière comprend un guide de lumière propre à transférer les photons générés, reçus sur une face d'entrée, vers une face avant située juste avant l'endroit prédéfini et propre à transférer ces photons dans ce dernier.

The first zones have a first color and the second zones may have a second color;

• ➢ the first color is a so-called transparent white crystal color and the second color is opaque black;
• ➢ the screen is a part in which the first zones are made of a first plastic material having the first color and the second zones are made of a second plastic material having the second color;
  • the part comprises first and second sub-parts made respectively from the first and second plastic materials. The first sub-part is fixedly secured to at least one part of an external face of the second sub-part, oriented opposite the predefined location, and the second sub-part comprises through holes defined in front of portions of the first subpart which respectively define the first zones;
• ➢ in an embodiment not forming part of the invention, the screen can be a piece of plastic or glass having the first color and comprising a face provided with added elements having the second color and defining the second zones ;
  • the light source comprises at least one light-emitting diode, optionally of the organic type;
• ➢ the light source comprises a light guide capable of transferring the photons generated, received on an input face, to a front face located just before the predefined location and capable of transferring these photons into the latter.

The invention also proposes a vehicle optical unit, possibly of the automobile type, and comprising at least one lighting device of the type presented above.

The invention also proposes a vehicle, possibly of the automobile type, and comprising at least one lighting device of the type of that presented above or at least one optical unit of the type of that presented above.

• la figure 1 illustre schématiquement, dans une vue en coupe dans un plan XY, un exemple de bloc optique comprenant un exemple de réalisation d'un dispositif d'éclairage selon l'invention, et
• la figure 2 illustre schématiquement, dans une vue de face, un exemple de bande lumineuse obtenu au moyen du dispositif d'éclairage de la figure 1.

Other characteristics and advantages of the invention will appear on examination of the detailed description below, and the appended drawings, in which:

• there figure 1 illustrates schematically, in a sectional view in a plan XY, an example of an optical unit comprising an exemplary embodiment of a lighting device according to the invention, and
• there figure 2 schematically illustrates, in a front view, an example of a light strip obtained by means of the lighting device of the figure 1 .

The invention aims in particular to propose a DE lighting device intended to provide at least one photometric function.

In what follows, we consider, by way of non-limiting example, that the lighting device DE is intended to equip an optical unit BO of an automobile type vehicle, such as for example a car. But the invention is not limited to this application. Indeed, a DE lighting device can be equipment in itself (possibly including its own housing), or can be part of equipment other than a vehicle optical unit. Thus, a DE lighting device can be part of any vehicle (land, sea (or river), or air), of any installation, including industrial type, of any device ( or system), and of any building.

Furthermore, we consider in what follows, by way of non-limiting example, that the optical unit BO (comprising at least one lighting device DE) is a front light ensuring at least one photometric signaling function, such as for example a position light function (or night light or even lantern) and/or a daytime running light function (or DRL (for “Daytime running Light (or Lamp)” - light signaling automatically switched on when the vehicle is put into operation during the day)). But the invention is not limited to this application. Indeed, the DE lighting device, according to the invention, is a luminous device capable of providing at least one photometric function of lighting or signaling or of a lighting effect, possibly decorative.

On the figures 1 and 2 , the direction the longitudinal direction X, and the direction Z is a vertical direction, perpendicular to the longitudinal X and transverse Y directions.

We have schematically illustrated on the figure 1 , part of a vehicle BO optical unit (here a front light) comprising a DE lighting device according to the invention.

As illustrated, this BO optical unit includes in particular a BB box secured to a part of the CV bodywork of a vehicle (here in a left front part).

The BB housing is made of a rigid material, such as for example a plastic or synthetic material. In this case, it can be made by molding. This BB box delimits part of a cavity housing a lighting device DE according to the invention, as well as possible other lighting means ensuring at least one other photometric function.

As illustrated on the figure 1 , a lighting device DE, according to the invention, comprises at least one light source SL and a screen EC.

The light source SL is capable of delivering photons to a predefined location EP which must provide at least one photometric function.

This light source SL comprises at least one photon generator, in the form of a light-emitting diode (or LED (“Light-Emitting Diode”)), optionally of organic type (or OLED (“Organic Light-Emitting Diode”) Alternatively, each photon generator could be a laser diode.

Note, although this does not appear on the figure 1 , that each photon generator can, for example, be installed on a support plate. This support plate can, for example, be a printed circuit board, of the PCB type (“Printed Circuit Board”), rigid or flexible (“Flex” type).

As illustrated on the figure 1 , the light source SL also includes a light guide GL capable of transferring the photons, generated by the photon generator(s) and received on an input face, to a front face FV which is located just before the predefined location EP and which is suitable for transferring these photons into the latter (EP). This entry face is for example located at one end of the light guide GL.

For example, the GL light guide can be made in polycarbonate (or PC) or poly-methyl methacrylate (or PMMA).

In order to optimize the delivery of photons in the predefined location EP located in front of the front face FV of the light guide GL, the lighting device DE can comprise a reflector RL partially surrounding the latter (GL) on the side of one face rear opposite its front face FV. This RL reflector can be made by molding in a plastic or synthetic material, for example white in color.

When the lighting device DE is part of an optical unit BO, the reflector RL is secured to an internal face of the housing BB which delimits a part of the aforementioned cavity.

The EC screen is placed in front of the predefined location EP and includes an alternation of first Z1 and second Z2 zones. By “alternation” we mean here a sequence of type Z1, Z2, Z1, Z2, Z1, Z2, as illustrated non-limitingly in the figure 2 .

Each first zone Z1 has a first light transmission coefficient ct1. Each second zone Z2 has a second light transmission coefficient ct2 which is strictly lower than the first light transmission coefficient ct1 (i.e. ct2 > ct1). Thus, the light which results (or is constituted) from the photons passing through each first zone Z1 has an intensity which is strictly greater than the intensity of the light which results (or is constituted) from the photons passing through each second zone Z2. This makes it possible to define a light strip BL comprising an alternation of portions of “high” intensity and “low” (or even zero) intensity, as in the example illustrated non-limitingly on the figure 2 .

The first zones Z1 have a first color and the second zones Z2 have a second color.

The first color is a color called transparent white crystal and the second color is opaque black, as in the example illustrated non-limitingly on the figure 2 .

The EC screen is a part in which the first zones Z1 are made of a first plastic material having the first color and the second zones Z2 are made of a second plastic material having the second color. Such an EP part can, for example, be produced by molding.

The EC part includes, as illustrated without limitation on the figure 1 , of the first SP1 and second SP2 sub-parts made respectively in the first and second plastic materials. The first sub-part SP1 is fixedly attached to at least part of one external face of the second sub-part SP2. This external face is oriented opposite the predefined location EP, that is to say towards the outside of the optical block BO. The second sub-part SP2 comprises through holes TT located in front of portions of the first sub-part SP1 which respectively define the first zones Z1.

It will be understood that the portions of the second sub-part SP2 which are full and therefore which surround the through holes TT define second zones Z2. The photons can thus pass freely from the predefined space EP to the first zones Z1 of the first sub-part SP1 via the through holes TT, then cross these first zones Z1 in order to emerge outside the optical block BO (in front of the face external of the first subpart SP1 and therefore of the EC screen). On the other hand, when photons strike a second zone Z2 which is opaque (i.e. ct2 = 0), they are absorbed or reflected towards the predefined space EP, which allows them to then be reflected by the reflector RL towards first zones Z1.

Such an EC part can for example be produced by injection molding of two materials of different colors.

In a variant embodiment not forming part of the invention, the EC screen can be a piece of plastic or glass having the first color and comprising a face (preferably internal) provided with added elements having the second color and defining the second zones Z2. These elements can, for example, be defined by pad printing (for example with ink), or else be parts joined together by gluing, possibly thermally.

It will be noted that when the lighting device DE is part of an optical unit BO, the screen EC can cooperate with the housing BB to delimit the cavity, in particular in a front part, as illustrated non-limitingly in the figure 1 .

• elle permet d'obtenir un encombrement, suivant la direction générale de propagation des photons, moins important que celui d'un dispositif d'éclairage de l'art antérieur, du fait de l'absence de masque à trous,
• elle évite la formation de condensation du fait de l'absence de masque à trous entre la source de lumière et l'écran,
• elle permet d'obtenir un meilleur rendement lumineux du fait que la source de lumière est plus proche de l'écran en raison de l'absence de masque à trous,
• elle évite les problèmes de positionnement de l'écran en raison de l'absence de masque à trous,
• elle permet de simplifier l'assemblage du dispositif d'éclairage et son éventuelle intégration dans un bloc optique, en raison de l'absence de masque à trous.

The invention offers several advantages, including:

• it makes it possible to obtain a smaller footprint, following the general direction of propagation of the photons, than that of a lighting device of the prior art, due to the absence of a mask with holes,
• it avoids the formation of condensation due to the absence of a mask with holes between the light source and the screen,
• it makes it possible to obtain better light output because the light source is closer to the screen due to the absence of a mask with holes,
• it avoids screen positioning problems due to the absence of a mask with holes,
• it makes it possible to simplify the assembly of the lighting device and its possible integration into an optical unit, due to the absence of a mask with holes.

Claims (3)

1. Lighting device (DE) comprising a light source (SL) capable of delivering photons to a predefined location (EP) which must ensure at least one photometric function further comprising a screen (EC) placed in front of said predefined location ( EP) and comprising an alternation of first (Z1) and second (Z2) zones, defining a light band (BL), the first (Z1) and second (Z2) zones respectively having a first light transmission coefficient and a second coefficient of light transmission strictly lower than said first light transmission coefficient, so that the light resulting from the photons passing through each first zone (Z1) has an intensity strictly greater than the intensity of the light resulting from the photons passing through each second zone (Z2);

   said first zones (Z1) have a first color and said second zones (Z2) have a second color;

   said first color is a so-called transparent white crystal color and said second color is opaque black;

   said screen (EC) is a part in which said first zones (Z1) are made of a first plastic material having said first color and said second zones (Z2) are made of a second plastic material having said second color;

   said part (EC) comprises first (SP1) and second (SP2) sub-parts made respectively of said first and second plastic materials, said first sub-part (SP1) being furthermore fixedly secured to a part of at least one external face of said second sub-part (SP2), oriented opposite to said predefined location (EP), and said second sub-part (SP2) comprising through holes (TT) in front of portions of said first sub-part ( SP1) which respectively define said first zones (Z1);

   said light source (SL) comprises at least one light-emitting diode;

   said light source (SL) comprises a light guide (GL) suitable for transferring said generated photons, received on an input face, to a front face (FV) located just before said predefined location (EP) and suitable for transferring these photons in the latter (EP).
2. Vehicle optical unit (BO), characterized in that it comprises at least one lighting device (DE) according to claim 1.
3. Vehicle, characterized in that it comprises at least one optical unit (BO) according to claim 2.

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