EP3519727B1 - Improved light-emitting module for a motor vehicle - Google Patents

Description

The field of the invention relates to light emitting devices for motor vehicles, and in particular to lighting and/or signaling devices.

In known manner, a large number of these devices comprise a light emission module provided with a plurality of photoemissive elements forming the light emission core of the device. In certain applications, in particular for signaling devices intended to be arranged at the rear of a vehicle, the devices have a curved profile, that is to say curved, so as to match the shape of the bodywork at the level from which they are received.

The document EP 2 671 756 A2 describes a light emitting module which comprises the technical characteristics of the preamble of claim 1.

This geometric configuration results in numerous constraints on the design of the devices. Indeed, in particular, in addition to possible considerations of homogeneity of the light rendering obtained which must result in a difficulty or even an impossibility for the observer to distinguish the photoemissive elements in a unitary manner within it, this type of device is subject to regulations which require in particular the device to have a spatial distribution of light intensity having minimum values in certain directions and/or not exceeding maximum values in other directions.

However, obtaining a device that is both curved and has these properties is not easy.

A solution commonly used to achieve this result consists of having a substrate receiving the photoemissive elements in the form of a plurality of flat plates disjointed from each other and oriented in a chosen manner, for example substantially orthogonal to one or several directions of light emission that regulations require to be favored.

This solution itself has disadvantages, particularly in terms of compactness and complexity. Indeed, due to the curve of the device, these plates must have a relative staircase arrangement, which results in a significant occupied volume and in the presence of numerous elements for connecting and fixing the plates within the device.

In practice, this makes this solution expensive, difficult to apply in certain cases, or even unusable.

Also, the invention aims to propose a light emission module and a light emission device which does not have these drawbacks.

• un substrat comprenant une portion principale courbe,
• des éléments photoémissifs agencés sur une face du substrat et configurés pour générer des rayons lumineux,
• un écran courbe agencé en regard de ladite face du substrat et à l'écart de ladite face, l'écran étant adapté pour présenter une surface éclairée à partir des rayons lumineux émis par les éléments photoémissifs, l'écran présentant des propriétés de diffusion de la lumière émise par les éléments photoémissifs,

• chaque élément photoémissif étant agencé sur le substrat au niveau d'une zone donnée, chaque élément photoémissif étant en outre agencé pour émettre les rayons lumineux correspondant selon une direction principale d'émission décalée angulairement d'une direction locale normale au substrat au niveau de ladite zone donnée
• caractérisé en ce que:
  • le substrat comprend une pluralité de languettes s'étendant à partir de la portion principale au niveau d'une région centrale du substrat, au moins une partie des éléments photoémissifs étant agencée sur lesdites languettes;
  • chaque languette est sensiblement plate; et
  • les languettes s'étendent sensiblement dans un plan tangent localement à la portion principale.

For this purpose, the invention relates to a light emission module, in particular for a motor vehicle, the light emission module comprising:

• a substrate comprising a curved main portion,
• photoemissive elements arranged on one face of the substrate and configured to generate light rays,
• a curved screen arranged facing said face of the substrate and away from said face, the screen being adapted to present a surface illuminated from the light rays emitted by the photoemissive elements, the screen having diffusion properties of the light emitted by the photoemissive elements,

• each photoemissive element being arranged on the substrate at a given zone, each photoemissive element being further arranged to emit the corresponding light rays in a main direction of emission angularly offset from a local direction normal to the substrate at said given area
• characterized in that:
  • the substrate comprises a plurality of tabs extending from the main portion at a central region of the substrate, at least a portion of the photoemissive elements being arranged on said tabs;
  • each tab is substantially flat; And
  • the tongues extend substantially in a plane locally tangent to the main portion.

According to one aspect of the invention, for at least part of said photoemissive elements, the main direction of emission of each photoemissive element of said part is substantially parallel to a local plane tangential to the zone of the substrate associated with the photoemissive element considered. .

According to one aspect of the invention, the main portion of the substrate and the screen are substantially parallel. According to one aspect of the invention, for at least a part of the photoemissive elements, the photoemissive elements of said part are arranged along a longitudinal direction of the substrate, the distances separating two consecutive elements along said direction being substantially identical. According to one aspect of the invention, the photoemissive elements are substantially at the same distance from the screen, the distance between two consecutive photoemissive elements being less than or equal to the distance separating the photoemissive elements from the screen.

According to one aspect of the invention, the illuminated surface of the screen is homogeneous during operation of the light emission module.

According to one aspect of the invention, the screen and the substrate define between them a space extending from the screen to the substrate, said space comprising a gas and the photoemissive elements, said space being devoid of optical deflection element of the light emitted by the photoemissive elements or an element for guiding the light emitted by the photoemissive elements other than said gas and said photoemissive elements.

According to one aspect of the invention, the photoemissive elements are in contact with said gas.

According to one aspect of the invention, the substrate is made from a reinforced epoxy resin composite and has a thickness of between 0.3 mm and 1.6 mm.

According to one aspect of the invention, the face of the substrate carrying the photoemissive elements is adapted to reflect at least part of the light emitted by the photoemissive elements reaching it.

According to one aspect of the invention, the face of the substrate carrying the photoemissive elements is adapted to diffuse at least part of the light emitted by the photoemissive elements reaching it.

According to one aspect of the invention, at least two photoemissive elements are arranged side by side along the substrate, at least one of said two photoemissive elements being pivoted towards the other or away from the other, so that the respective main directions of emission of the two photoemissive elements are coplanar and not parallel.

According to one aspect of the invention, the light emission module further comprises shaping optics interposed between at least one photoemissive element and the screen, the shaping optics being configured to deflect at least a portion of the light emitted by said at least one photoemissive element.

According to one aspect of the invention, the screen is made from a material having diffusion properties.

According to one aspect of the invention, the screen has a face comprising microstructures adapted to diffuse the light emitted by the photoemissive elements.

According to one aspect of the invention, the light emission module further comprises a control assembly adapted to control at least the switching on and off of the photoemissive elements.

Advantageously, the control assembly comprises a plurality of control modules respectively coupled to photoemissive elements. The control modules are for example arranged on the substrate at a face thereof opposite to that carrying the photoemissive elements.

The invention further relates to a lighting and/or signaling device for a motor vehicle, the lighting and/or signaling device comprising a light emission module as defined above.

According to one aspect of the invention, the motor vehicle extends along an axis, the light emission module having a preferred direction of light emission substantially parallel to said axis of the motor vehicle and substantially horizontal.

According to one aspect of the invention, the motor vehicle extends along an axis, the contour of the main portion of the substrate and the contour of the screen having substantially the same shape in projection on a plane orthogonal to said axis of the vehicle.

According to one aspect of the invention, the lighting and/or signaling device further comprises a housing and a closing glass cooperating with one another to delimit a cavity receiving all or part of the light emission module.

According to one aspect of the invention, the lighting and/or signaling device further comprises a receiving housing provided within the cavity and receiving all or part of the light emission module, the screen closing at least part of said accommodation.

• Les Figures 1a et 1b sont des illustrations schématiques d'un dispositif d'émission lumineuse selon l'invention ;
• La Figure 2 illustre une vue de face d'une partie d'un module d'émission lumineuse du dispositif de la Figure 1 ;
• La Figure 3 illustre une vue du dessus d'un module d'émission lumineuse selon l'invention ; et
• La Figure 4 est une illustration schématique d'un écran de diffusion d'un module d'émission lumineuse selon l'invention.

The invention will be better understood on reading the detailed description which follows, given solely by way of example and made with reference to the appended figures, in which:

• THE Figures 1a and 1b are schematic illustrations of a light emitting device according to the invention;
• There Figure 2 illustrates a front view of a part of a light emitting module of the device of the Figure 1 ;
• There Figure 3 illustrates a top view of a light emitting module according to the invention; And
• There Figure 4 is a schematic illustration of a diffusion screen of a light emission module according to the invention.

THE Figures 1a and 1b illustrate a light emitting device 2 according to the invention, hereinafter device 2.

Device 2 is configured to emit light.

In the context of the invention, the device 2 is advantageously intended to be integrated into a motor vehicle. In other words, it is a light emitting device for a motor vehicle.

Advantageously, the device 2 is a lighting and/or signaling device for a motor vehicle.

It is for example configured to implement one or more photometric functions.

A photometric function is for example a lighting and/or signaling function visible to a human eye. Note that these photometric functions may be the subject of one or more regulations establishing requirements for colorimetry, intensity, spatial distribution according to a so-called photometric grid, or even visibility ranges of the emitted light.

The device 2 is for example a lighting device and then constitutes a vehicle headlight - or headlight - intended to be arranged at the front of the vehicle. It is then configured to implement one or more photometric functions, for example chosen from a low beam function called a “code function”, a high beam function called a “road function”, a fog light function.

Alternatively or in parallel, the device is a signaling device intended to be arranged at the front or rear of the vehicle.

When it is intended to be arranged at the front, the photometric functions that it is configured to implement (possibly in addition to those that it implements in its capacity as a lighting device) include a direction change indication function, a daytime running light function known by the English acronym DRL, for “Daytime Running Light”, a front light signature function, a position light function, a so-called “Side” function -marker”, which comes from English and can be translated as lateral signaling.

When it is intended to be arranged at the rear, these photometric functions include a reversing indication function, a stop function, a fog light function, a direction change indication function, a rear light signature function, a lantern function, a “Side-marker” function.

Alternatively, the device 2 is intended for lighting the passenger compartment of a vehicle and is then intended to emit light mainly into the passenger compartment of the vehicle.

In the following, the device 2 is described in a non-limiting manner in a configuration in which it is intended to emit light outside the vehicle and is a rear signaling device.

With reference to Figures 1a and 1b , the device 2 comprises a housing 4 and a closing glass 6 cooperating with one another to internally delimit a cavity 8, as well as a light emission module 10 according to the invention, hereinafter module 10.

In the context of the invention, the device 2 is curved, or curved. In other words, seen from above, the housing and the glass are curved, here to match the shape of the vehicle body at the region in which the device 2 is intended to be arranged. The leftmost portion of the device Figure 1b is for example intended to be arranged on the exterior side of the vehicle, the right part being conversely oriented towards a median plane of the vehicle.

Module 10 is arranged in whole or in part in cavity 8.

In certain embodiments, the device 2 comprises a receiving housing 12 for receiving the module 10. This housing is for example provided in the housing 4. As described below, this receiving housing 12 is advantageously closed towards the front by an element forming a screen for diffusing the light generated by the module 10. The internal face(s) of the housing 12 advantageously have reflective and diffusing optical properties.

Module 10 is configured to emit light. Advantageously, as in the example of Figures 1a and 1b , it is arranged to emit light towards the closing glass (which is transparent for at least part of this light emitted by module 10).

In the context of the invention, the device 2 is configured to present a spatial distribution of light intensity having, for at least a plurality of given directions, minimum and/or maximum values. In other words, according to these directions, the light intensity emitted by the device 2 must be greater and/or less than a predetermined threshold value. Threshold values are for example defined by one or more regulations. Such a direction P is illustrated in Figure 1b , and is for example a horizontal direction (in the sense of the orientation of the device 2 within the vehicle) parallel to an axis of movement X of the vehicle along which the vehicle extends and according to which the light intensity emitted by the device 2 must be greater than a given threshold value. This direction P can be seen as a preferred direction of emission (among a plurality).

These intensity distribution considerations result in strong constraints on the module 10 in terms of light intensity emitted as a function of the direction considered.

With reference to Figures 1a, 1b And 2 , the module 10 comprises a substrate 14, photoemissive elements 16 and a screen 18.

The substrate 14 forms a support for the photoemissive elements 12.

In addition, it is configured to convey electrical energy to the photoemissive elements 12 for the generation of light rays by them. For this purpose, it comprises means for conveying electrical energy configured for connecting the elements 12 to a source of electrical energy. These means include, for example, metal or metallized connection elements, such as copper tracks or wires.

The substrate 14 has the general shape of a plate. In other words, its thickness is small compared to its other dimensions. It is for example of a generally polygonal shape, such as rectangular. Its corners are optionally rounded.

In this respect, we note that the Figure 2 illustrates two substrates 14 arranged in contact with each other. They can be seen as belonging to distinct modules 10 that the device 2 comprises. In this configuration, as described below, the respective screens 18 of the modules 10 are for example formed on the same part. As also illustrated in this Figure, the substrate 14 is arranged substantially horizontally relative to the orientation of the vehicle (upper substrate), or is inclined relative to the horizontal (lower substrate).

The substrate 14 has a contour C having rectilinear or non-rectilinear edges. In practice, the shape of the contour C is advantageously chosen to correspond to the shape of the contour of the screen 18 associated in projection on a plane orthogonal to the axis X of the vehicle. Here, we mean that the outline of the substrate has the same general shape as that of the screen, but not necessarily the same dimensions. Furthermore, this is understood at a rotation around an axis parallel to the X axis.

The substrate 14 comprises a main portion 20 and tabs 22.

The main portion 20 gives the substrate 14 its general appearance. It has, for example, a general polygonal shape, such as rectangular. For example, it is formed by the entire substrate with the exception of the tabs 22 described below. However, in certain embodiments, the substrate may comprise regions other than the main portion and the tabs, and which extend for example from the outer edge of the main portion and away from the main portion. These regions are for example intended for receiving connectors or for fixing the substrate to the rest of the device 2.

Note that in this configuration, the contour C corresponds to the contour of the main portion, ignoring these extension regions.

Advantageously, the main portion 20 is flexible. More specifically, it is adapted to deform elastically, in particular under the effect of a bending force, such as a bending tending to bring its longitudinal ends closer to each other and applied normally to one face of the substrate .

This allows in particular the main portion and the substrate in general to be curved, in particular with a view to arranging the main portion of the substrate substantially parallel to the closing glass 6 and/or to the rear wall of the housing 4 when the device 2 is curved.

The tabs 22 are in the form of material tongues. They extend from the main portion. More specifically, they each extend from an internal edge of the main portion. In other words, they do not extend from an external edge of the substrate 14, that is to say from the edge facing outwards of the substrate 14.

These tabs are for example formed by cutting the substrate, which initially has a solid surface.

In practice, these tabs 22 are connected to the main portion 20 by a connection edge 22B (dotted on certain tabs of the Figure 2 ), and their other edges are free, that is to say disjointed from the substrate 14. The connection edge 22B is for example integral with the main portion.

Advantageously, the tongues have a general polygonal shape, such as rectangular, all or part of the angles of which are optionally rounded. The connection edge 22B corresponds to at least one side of this polygon, the other sides forming free edges.

Advantageously, they have substantially identical dimensions, at least for part of them. Note that for reasons of bulk or shape of the substrate, the end tabs can be made to have dimensions or even a shape different from those of the tabs which are not proximal relative to the ends of the substrate.

The tongues 22 are substantially flat. Furthermore, advantageously, they are arranged to remain substantially flat in the event of elastic bending of the main portion.

There Figure 3 illustrates the geometric configuration of the tabs in such a flexed configuration. In this configuration, the tongues extend substantially in a plane locally tangent to the main portion.

The tongues are advantageously made from the same material as the rest of the substrate 14. Their flatness, particularly in the flexed configuration of the main portion, has the effect of limiting the transmission of bending forces exerted on the main portion to the components arranged on the tabs and/or the welds making said components integral with the surface of said tabs, and results in maintaining their planar configuration while the main portion flexes.

The substrate 14 comprises for example a plurality of tabs 22 arranged consecutively along the substrate. They are for example thus arranged in an aligned manner along a longitudinal direction of the substrate.

For example, they have the same spatial orientation. For example, as illustrated in Figure 2 , their connection edge 22B forms a longitudinal end of the proximal tongues relative to the same end of the substrate, the opposite edge being turned towards the tongue 22 coming afterwards in the direction of travel of the substrate from this end towards the other end.

Preferably, the connection edge 22B of the tabs is substantially parallel to the axis of local curvature of the substrate. In this way, the tabs are only slightly or not mechanically constrained by the bending force of the substrate 14.

Note that the substrate can include a line of tabs as illustrated in Figure 2 , or else a plurality of lines of tongues extending parallel to each other and offset from each other transversely to this longitudinal direction.

The substrate is for example made from an epoxy resin composite reinforced, typically with glass fibers. For example, it is made from a material commonly called PCB FR-4 (PCB being the English acronym for Printed Circuit Board).

It advantageously has a thickness of between 0.3 mm and 1.6 mm. This configuration, combined with the presence of openings (the contour of the tabs) made in the surface of the substrate, makes it possible to promote the flexibility of the substrate and makes it possible to dispense with expensive materials commonly used to form flexible substrates.

As described below, the photoemissive elements are arranged on a given face 24 of the substrate. Advantageously, this face 24 is adapted to reflect at least part of the light coming from the elements 16 and reaching them.

For example, for this purpose, this side is white.

Advantageously or in parallel, this face 24 is also configured to diffuse at least part of the light coming from the elements 16 and reaching it.

For example, for this purpose, it has suitable roughness.

Note that the substrate is advantageously made in a single piece of the same material, as opposed to a configuration of portions of different materials connected to each other and forming a heterogeneous substrate. Formulated differently, the main portion extends from one end to the other of the substrate and is formed of a single portion made of a given material, the tabs being made integrally with this portion.

The photoemissive elements 16 are each configured to emit light when supplied with electrical energy appropriately. These elements 16 form the light emission core of module 10.

Advantageously, these elements 16 are semiconductor photoemissive elements adapted to generate photons by electroluminescence. Advantageously, each element 16 of at least part of the elements 16 that the module 10 comprises is formed from a light-emitting diode.

For example, all of them are. Here we mean “formed from” that the light-emitting structure that the element 16 comprises is a light-emitting diode, sometimes called an LED chip.

In practice, in the context of the invention, at least part of the photoemissive elements 16 comprises a diode and a housing 26 within which the corresponding diode is arranged. 26 boxes are sometimes called "packages", which comes from English and can be translated as box. The diodes themselves are sometimes called LED chips, and form the photoemissive structure of the photoemissive element.

The arrangement of the diode within the housing is chosen to obtain a main direction of emission of the corresponding diode which is chosen at the given orientation of the associated housing 26. This main direction corresponds to the direction in which the element 16 considered emits maximum light intensity.

The photoemissive elements 12 are arranged on the substrate. As indicated previously, they are arranged on the same face 24 of the substrate. This face 24 faces the screen 18 and the closing glass 6.

For this purpose, the boxes 26 are fixed on the face 24.

In the context of the invention, the photoemissive elements are advantageously arranged on the tabs 22 of the substrate.

They are advantageously arranged in one or more lines. These lines are advantageously each parallel to a longitudinal direction of the substrate (which can be curved depending on the configuration of the substrate 14 considered).

In the example of the Figures, the elements 16 are thus arranged in two parallel lines.

Advantageously, the distance separating two consecutive elements 16 along the substrate is substantially constant.

Advantageously, for at least part of the elements 16, each element 16 is associated with at least one element 16 located substantially at the same location along the substrate. In other words, the corresponding photoemissive elements are also arranged in columns each comprising at least two elements 16. Each column is advantageously substantially perpendicular to the longitudinal direction at least locally.

Advantageously, the distance separating two adjacent elements within a given column is substantially constant within the column, and preferably is the same for all the columns defined by the arrangement.

Note that optionally, the distance separating two consecutive elements within a row is the same as that separating two consecutive elements within a column.

The distance separating two consecutive elements 16 within a row and/or a column is for example between the distance which separates the substrate from the screen, and 40% of this value.

In the context of the invention, for at least part of the elements 16, the elements 16 are configured to present a main direction of emission angularly offset from the direction normal to the substrate at the level of the zone of the substrate carrying the element 16 considered. In other words, this direction does not correspond to the local normal to the substrate.

For example, the elements 16 are configured to emit light in a preferred main direction angularly between a plane parallel to a local plane tangential to the corresponding zone of the substrate and the local normal to the substrate.

Advantageously, the corresponding elements 16 are configured to emit light in a preferred direction included in a plane substantially parallel to the local plane tangential to the zone of the corresponding substrate. In other words, as illustrated in Figure 3 , the photoemissive elements are configured so that this direction is parallel to the tab 22 on which they are located.

The corresponding elements 16 are light-emitting diodes known by the English name “Side-LED”, which can be translated as “side LED”.

In practice, the desired main direction is obtained by arranging the diode within the corresponding housing 26 appropriately.

Note that these configurations can be combined, the module 10 comprising elements 16 emitting parallel to the local tangential plane to the substrate considered and/or others emitting angularly between the plane parallel to the local tangential plane and the normal to the zone considered.

Furthermore, in addition to the photoemissive elements having a main direction of emission such as above, the module 10 can comprise photoemissive elements whose main direction corresponds substantially to the local normal to the substrate.

On the Figure 3 , the main directions oriented parallel to the local tangential plane have the references dp3 to dp6 and the associated local normals have references n _loc3 to n _loc6 . The main directions having a configuration simply inclined with respect to the other corresponding normal are referenced dp1 and dp2 (the associated local normals are referenced n _loc1 and n _loc2 ).

In certain configurations, the module 10 only comprises elements 16 having a main direction parallel to the local tangential plane.

Within a given column, for example for two consecutive photoemissive elements, the main directions are or are not substantially parallel to each other.

For example, for certain photoemissive elements, one and/or the other of the two photoemissive elements is pivoted relative to the other along an axis normal to the zone of the substrate carrying the element 16 considered. In this way, their main directions of emission are substantially coplanar but not parallel.

In certain embodiments, they are pivoted towards each other so that their main directions (that is to say here the original half-axis of the element 16 considered) intersect, as illustrated in Figure 2 for the rightmost tab. This makes it possible, for example, to compensate for the possible appearance of darker zones within the device in a region located between the two elements 16.

Alternatively, one and/or the other is pivoted away from the other, as illustrated on the lower substrate.

For example, for this substrate, and in general in particular for substrates oriented other than horizontally, one of the two photoemissive elements has a main direction of emission aligned with the longitudinal direction of the substrate (possibly considered locally at the level of the zone carrying the photoemissive element considered when the substrate does not extend in a rectilinear direction), and the other a main horizontal direction.

The module 10 is for example configured to emit white, or even red or amber, light. Other colors are still possible depending on the intended application.

Note that the module 10 can include elements 16 configured to emit white light, others in amber color and/or others in red color.

The screen 18 is configured to form a surface illuminated from the light emitted by the elements 16. In addition, it is configured to diffuse at least part of the light received from the photoemissive elements and passing through it.

More specifically, together with the substrate 14 and the photoemissive elements, the screen is configured to form a substantially homogeneous illuminated surface. By homogeneous, we mean that the photoemissive elements are not distinguishable to the naked eye within this surface illuminated by an observer whose gaze is directed towards the screen.

In practice, this property results - all things being equal - from the combination of the distribution density of the photoemissive elements on the substrate and the distance between these photoemissive elements and the screen.

Advantageously, for this purpose, for at least part of the photoemissive elements and advantageously for all, the distance between two adjacent photoemissive elements is less than or equal to the distance which separates them from the screen, and advantageously less than 70% of the latter .

We note that homogeneity can be quantified.

For example, by denoting it H, it can be determined from or as a minimum between on the one hand a local uniformity L_U and a global uniformity G_U.

où ROI désigne la surface éclairée formée par l'écran et L_ROI désigne la luminance de la surface éclairée (σ désigne l'écart-type et Moy la moyenne).The overall uniformity is for example determined from the relationship: $$G\_u=100\ast \left(1-\frac{\sigma \left(L_{\mathit{KING}}\right)}{\mathit{Avg}\left(L_{\mathit{KING}}\right)}\right)$$

where ROI designates the illuminated surface formed by the screen and L _ROI designates the luminance of the illuminated surface (σ designates the standard deviation and Avg the mean).

The local uniformity is for example determined as follows. We consider a pixel X of the illuminated surface, the square region of side n (for example n pixels) centered _on a distance n from the point X. The points Xi are for example regularly distributed around X.

, où M et Mi sont les luminances moyennes des pixels de la région centrée sur X, sur le Xi considéré respectivement.We define the local contrast l_c as a function of n according to the relation $L\_\mathrm{vs}\left(\mathrm{not}\right)={\mathit{max}}_{\forall X\in \mathit{KING}}\left({\mathit{max}}_{i=1,\dots ,8}\left(\frac{\left|M-\mathit{Mid}\right|}{\left|M+\mathit{Mid}\right|}\right)\right)$

, where M and Mi are the average luminances of the pixels of the region centered on X, on the Xi considered respectively.

We determine the magnitude MSlocal_contrast as the maximum of the local contrasts l_c(n) for n=2p+1, with p ranging from 1 to 20, and we determine the magnitude L_U according to the relation L_U=100(1-2MSlocal_contrast).

Note that in certain embodiments in which the device 2 comprises two relatively distinct zones, the overall homogeneity is for example determined as a minimum of the respective homogeneities of the two regions.

Furthermore, it can be determined as a linear combination (or alternatively, as a minimum) of the homogeneity considered along various axes.

Also, in the context of the invention, the homogeneity H is advantageously greater than 85%.

We note that the screen 18 is at least partly transparent to the light of the elements 16.

Several configurations are envisaged to obtain the diffusing effect of screen 18.

In a first configuration, the screen 18 is said to broadcast “into the mass”. In other words, it is made from a diffusing material. This type of material is sometimes called opalescent.

Alternatively, the screen has a surface provided with microstructures 28 intended to diffuse the light from the photoemissive elements. They are advantageously designed to diffuse light by diffraction in transmission.

These microstructures 28 are for example formed in the surface of the external face of the screen, that is to say the face facing the closing glass. They are present over the entire surface of the screen (they are illustrated on only part of the screen 18 in Figure 4 for the sake of clarity).

Advantageously, the microstructures 28 are obtained by injection.

These microstructures are for example in the form of depressions or projections formed in the surface of the face of the screen. They have characteristic dimensions of an order of magnitude between that of the wavelength of the light emitted by the photoemissive elements and a hundred times this order of magnitude.

Advantageously, the microstructures have a diffusion profile having a total width at half height whose opening angle at the top is between 25° and 80° in all directions on either side of the normal to the screen, more preferably between 30° and 60°.

The screen 18 has a general polygonal shape, such as rectangular, its angles being optionally rounded.

The screen is arranged facing the face of the substrate 14 carrying the photoemissive elements 16. It is located away from this face and the photoemissive elements.

The screen is located at a distance from the substrate, for example greater than 20 mm. It is for example between 20 mm and 90 mm.

Advantageously, the screen 18 is curved. Preferably, it has a curve identical to that of the substrate over at least part of its length. In other words, the screen, or more specifically its face carrying the microstructures, is arranged substantially parallel to at least part of the main portion of the substrate (that is to say the large face of the latter turned towards the screen). In this way, for at least part of the elements 16, all the photoemissive elements considered are all located substantially at the same distance from the screen 18.

Note that optionally, as illustrated in Figure 4 , the screen 18 is carried by a diffusion element 30 belonging to the module 10. In addition to the screen 18, this element 30 comprises a fixing portion 32 surrounding the screen over at least part of its periphery. This portion 32 is provided for fixing the element 30 within the volume 8, and optionally within the housing 12, as well as for gripping the element 30.

Note that element 30 can include several screens, as illustrated in Figure 4 . In this Figure, it comprises a first substantially horizontal screen and a second screen 18 ₂ of bent shape extending from the first in an inclined manner relative to the horizontal.

The screen is arranged within the device 2 so as to at least partially close the housing 12 towards the front.

As indicated previously, the screen and the substrate have respective contours whose shapes are advantageously a function of one another. Advantageously, the shape of the contour of the substrate corresponds to that of the contour of the screen in projection on a plane orthogonal to the axis

As such, in certain embodiments, the dimensions of the screen are greater than those of the substrate. In alternative configurations, the screen dimensions are smaller than the screen dimensions.

Optionally, the element 30 is coupled to an envelope 34 with which it cooperates or within which it is arranged, the envelope being arranged in the housing 12 or defining the housing (for example by forming all or part of its wall ). Jointly with element 30 or not, the envelope defines a closed volume in which the photoemissive elements and the substrate are arranged. This volume is configured so that the light from the photoemissive elements does not exit the device 2 without first passing through the screen 18.

Advantageously, the envelope has an internal face adapted to reflect and/or diffuse at least part of the incident light coming from the elements 16.

For example, it is white in color and/or has a surface metallization, and optionally presents a diffusing texturing on all or part of this internal face.

In addition to the components described above, the module 10 advantageously comprises a control assembly 36 ( Figure 2 ) adapted to control at least the switching on and off of the photoemissive elements. Advantageously, it is also configured to control the intensity of the light emitted by the photoemissive elements.

The assembly 36 comprises for example a plurality of control modules respectively coupled to a plurality of photoemissive elements for controlling them. These modules are for example distributed on the substrate, for example on the face of the substrate opposite to that receiving the elements 16.

Advantageously, the control assembly is configured for the implementation of a light sequence during which all or part of the elements 16 is sequentially and/or simultaneously turned on and/or off.

For example, this sequence is implemented in response to the detection of an event occurring at the vehicle level, such as the ignition of the vehicle, the opening of a door that it includes or the actuation of 'a direction change indication command.

The operation of device 2 will now be described with reference to the Figures.

During operation of the device, the photoemissive elements 16 are controlled to emit by the control assembly 36 via the electrical energy conveyed by the substrate 14. In response, these emit light with maximum intensity according to their main direction of emission. This light is then diffused by the screen 18, after possible reflections on the envelope 34 and/or the face 24 of the substrate. Due to the orientation of their respective emission directions, satisfaction of the requirements in terms of spatial distribution of light intensity of the device 2 is facilitated.

Optionally, at a given moment, the control assembly 36 implements a light sequence, for example in response to an event detected at the vehicle level, or to a failure of one or other of the photoemissive elements of the system.

The invention has several advantages.

First of all, it makes it possible to obtain a spatial distribution of light intensity of the device 2 within which certain directions normal to the screen do not form local intensity maxima by default, and this in a simple manner. . This is particularly advantageous in the curved configuration of the device 2.

In addition, the presence of the tabs 22 ensures good flatness of the interface of the photoemissive elements with the substrate and promotes the holding of the device 2 over time by minimizing the stresses induced at the level of the fixings of the photoemissive elements or even of the structure itself. these elements.

Furthermore, the light rendering obtained is homogeneous, that is to say that the photoemissive elements are not discernible, or at least difficult to discern, as emission units within the light rendering obtained.

In a particular embodiment, the module 10 comprises, in addition to the above elements, at least one optical shaping element interposed between at least one photoemissive element and the screen. Each optical shaping element is configured to deflect at least a portion of the light from the corresponding photoemissive elements.

However, preferentially, the volume delimited between the substrate and the screen (and which extends from one to the other) is devoid of optical element other than the gas filling this volume and the elements 16. This is that is to say that this volume is devoid of any element emitting light or deflecting light other than the elements 16 themselves and this gas (which is for example air), such as for example deflection optics or light guiding elements. In particular, in these embodiments, the module 10 is devoid of primary optics associated with the elements 16, such optics being presented for example in the form of a resin arranged in contact with the elements 16 and the substrate and interposed between the screen and the substrate, or even any optical light deflection element, such as a lens or an intermediate screen between the screen 18 and the elements 16. In practice, the photoemissive elements are in contact with this gas filling the volume between the screen and the substrate.

We further note that preferably, the elements 16 are devoid of a sub-component aimed at directing the maximum light intensity emitted by each of them in a direction different from that in which they would emit it in the absence of this component. . For example, certain known LED type photoemissive elements include an optical lens type device mounted integrally with the housing, components of this type having an impact on the optical behavior of the element considered resulting in a deviation in the maximum light intensity emitted by the elements 16. Advantageously therefore, the elements 16 of the device 2 according to the invention are devoid of such components: for financial reasons, it will in fact be preferable to optimize the spatial distribution of light intensities of the device by optimizing the arrangement of the elements 16 on the substrate, as well as the control of these elements 16, rather than by costly adding an optical device in or on the structure of said elements 16 itself.

Note, however, that this does not exclude the presence of a protective material within the elements 16, in particular within the housing, this material being presented for example in the form of a layer deposited on the LED chip within of the corresponding box. Such layers are for example made from silicone or epoxy resin.

Claims (21)

1. Light-emitting module, in particular for a motor vehicle, the light-emitting module comprising:

   - a substrate (14) comprising a curved main section (20),

   - light-emitting elements (16) arranged on a face (24) of the substrate and configured to generate light rays,

   - a curved screen (18) arranged facing said face of the substrate and away from said face, an area of the screen being suitable for being illuminated by the light rays emitted by the light-emitting elements, the screen having scattering properties with respect to the light emitted by the light-emitting elements,

   each light-emitting element being arranged on the substrate in a given zone, each light-emitting element furthermore being arranged to emit the corresponding light rays in a main emission direction (dp1, ..., dp6) that is angularly offset from a local direction (n_loc1, ..., n_loc6) that is normal to the substrate in said given zone.

   characterized in that

   - the substrate comprises a plurality of tabs (22) extending from the main section in a central region of the substrate, at least one subset of the light-emitting elements (16) being arranged on said tabs (22);

   - each tab is substantially planar; and

   - the tabs lie substantially in a plane that is locally tangent to the main section.
2. Light-emitting module according to Claim 1, wherein, with respect to at least one subset of said light-emitting elements (16), the main emission direction of each light-emitting element of said subset is substantially parallel to a local plane that is tangential to that zone of the substrate which is associated with the light-emitting element in question.
3. Light-emitting module according to Claim 1 or 2, wherein the main section (20) of the substrate and the screen (18) are substantially parallel.
4. Light-emitting module according to any one of the preceding claims, wherein, with respect to at least one subset of the light-emitting elements, the light-emitting elements of said subset are arranged along a longitudinal direction of the substrate, the distances separating two consecutive elements along said direction being substantially identical.
5. Light-emitting module according to any one of the preceding claims, wherein the light-emitting elements are substantially at the same distance from the screen, the distance between two consecutive light-emitting elements being smaller than or equal to the distance separating the light-emitting elements from the screen.
6. Light-emitting module according to Claim 5, wherein the illuminated area of the screen is uniform during operation of the light-emitting module.
7. Light-emitting module according to any one of the preceding claims, wherein the screen and the substrate define therebetween a space extending from the screen to the substrate, said space comprising a gas and the light-emitting elements, said space being devoid of optical elements for deviating the light emitted by the light-emitting elements or elements for guiding the light emitted by the light-emitting elements other than said gas and said light-emitting elements.
8. Light-emitting module according to Claim 7, wherein the light-emitting elements make contact with said gas.
9. Light-emitting module according to any one of the preceding claims, wherein the substrate is made from a reinforced epoxy-resin composite and has a thickness comprised between 0.3 mm and 1.6 mm.
10. Light-emitting module according to any one of the preceding claims, wherein the face (24) of the substrate bearing the light-emitting elements is suitable for reflecting at least some of the light emitted by the light-emitting elements that reaches it.
11. Light-emitting module according to any one of the preceding claims, wherein the face of the substrate bearing the light-emitting elements is suitable for scattering at least some of the light emitted by the light-emitting elements that reaches it.
12. Light-emitting module according to any one of the preceding claims, wherein at least two light-emitting elements (16) are arranged side-by-side along the substrate (14), at least one of said two light-emitting elements being pivoted toward the other or away from the other, so that the respective main emission directions of the two light-emitting elements are coplanar and nonparallel.
13. Light-emitting module according to any one of the preceding claims, furthermore comprising a shaping optic interposed between at least one light-emitting element (16) and the screen (18), the shaping optic being configured to deviate at least some of the light emitted by said at least one light-emitting element.
14. Light-emitting module according to any one of the preceding claims, wherein the screen is made from a material having scattering properties.
15. Light-emitting module according to any one of the preceding claims, wherein the screen has a face comprising microstructures (28) that are suitable for scattering the light emitted by the light-emitting elements.
16. Light-emitting module according to any one of the preceding claims, furthermore comprising a control assembly (36) suitable for controlling at least the turn-on and turn-off of the light-emitting elements.
17. Motor-vehicle lighting and/or signalling device, the lighting and/or signalling device comprising a light-emitting module according to any one of the preceding claims.
18. Lighting and/or signalling device according to Claim 17, the motor vehicle extending along an axis (X), the light-emitting module having a privileged direction (P) of light emission that is substantially parallel to said axis of the motor vehicle and substantially horizontal.
19. Lighting and/or signalling device according to Claim 17, the motor vehicle extending along an axis (X), the outline of the main section (20) of the substrate and the outline of the screen (18) having the same shape in projection on a plane orthogonal to said axis of the vehicle.
20. Lighting and/or signalling device according to any one of Claims 17 to 19, furthermore comprising a casing (4) and a closing outer lens (6) that interact with each other in order to define a cavity (8) that receives all or some of the light-emitting module.
21. Lighting and/or signalling device according to Claim 20, furthermore comprising an accommodating housing (12) produced within the cavity and that accommodates all or some of the light-emitting module, the screen (18) at least partially obturating said housing.

Images