WO2018185394A1

WO2018185394A1 - Oled-based signalling device for a vehicle with three-dimensional effect

Info

Publication number: WO2018185394A1
Application number: PCT/FR2018/050646
Authority: WO
Inventors: Nathalie Larribeau; Whilk Marcelino GONCALVES; Christophe Le Dall
Original assignee: Psa Automobiles Sa
Priority date: 2017-04-06
Filing date: 2018-03-16
Publication date: 2018-10-11
Also published as: FR3065054A1; FR3065054B1

Abstract

The present invention concerns a light signalling device comprising a first optical element (10) provided with a reflective surface, a second optical element (20) provided with a semi-reflective surface and arranged opposite and separated from the first optical element (10) so as to define between them a cavity (2), a light source (10) arranged so as to emit light rays penetrating into said cavity (2), a portion of these light rays being successively reflected by one and by the other of said optical elements (10, 20) in such a way as to generate a repetitive optical depth effect; the one of the optical elements and the light source consisting of an OLED (10) comprising, interposed between two electrodes (12, 14), one (14) of which constitutes the reflective or semi-reflective surface, a structured organic layer in a main central transparent non-electroluminescent zone (13A) and in a peripheral electroluminescent zone (13B).

Description

Title of the invention

OLED-based signaling device for a three-dimensional vehicle Field of the invention

The present invention relates generally to light signaling devices for a motor vehicle.

It aims a signaling device, including a position light located at the rear or the front of a vehicle, which is capable of generating a three-dimensional depth effect.

Background of the invention

In particular, such a device comprising a housing comprising a support on which are disposed peripherally a series of light-emitting diodes so as to form a general shape of a rectangle is known from the European application EP 1 916471 A1. The device also comprises a semi-reflective flat screen located above the support.

A reflector having a reflective convex outer surface is disposed between the support and the screen, this reflector comprising a series of orifices arranged in line with the light-emitting diodes along their main illumination axis.

The screen and the reflector form a cavity delimited essentially by the reflective outer surface of the reflector and by the inner surface of the screen.

The light rays emitted by the electroluminescent diodes that pass through the orifices penetrate into the cavity and meet the inner surface of the screen.

Part of the rays striking the screen is transmitted to the space to be illuminated and forms a first image. The other part of these other light rays is reflected by the screen towards the convex outer surface of the reflector. These rays are then reflected by the reflector towards the screen. These will then be, partly transmitted by the screen to the space to be illuminated by forming a second image and for part reflected again by the screen to the convex outer surface of the reflector, and so on so as to form a multitude of images whose light intensity gradually decreases.

Due to the curved nature of the reflector, the light rays reflected by the reflector are gradually shifted towards the center of the cavity, so that the generated images produce a series of concentric light rectangles giving a repetitive optical effect of depth.

However, the superposition of the support carrying the light-emitting diodes, the reflector and the screen induces a relatively large size of the device which complicates its integration with another structure, such as a front or rear optical unit of a motor vehicle. Object and summary of the invention

The present invention therefore aims to compact this type of three-dimensional effect signaling device.

It proposes for this purpose a signaling device for a motor vehicle capable of illuminating a space, said device comprising a first optical element having a reflecting surface, a second optical element having a semi-reflecting surface and arranged facing and remote from said first optical element so as to define between them a cavity, a light source arranged to emit light rays penetrating into said cavity, a portion of these light rays being successively reflected by one and the other of said optical elements so as to generate a repetitive optical effect of depth;

characterized in that one of said optical elements and said light source are constituted by an organic light-emitting diode (OLED) comprising, interposed between two electrodes, one of which constitutes said reflecting surface or said semi-reflecting surface, an organic layer structured in a non-electroluminescent transparent central main area and a light emitting peripheral area. The use of an OLED to replace both the light source (with its support) and one of the two optical elements (the semi-reflective screen or the reflector) makes it possible to improve very clearly the compactness of the signaling device according to the invention compared to existing devices and thus to facilitate its implementation in a motor vehicle

In addition, the many possibilities offered by the OLED, in particular in terms of shape, flexibility and selection of light areas, allow to obtain much more advanced light effects and in particular dynamic type.

According to preferred features of the device, taken alone or in combination:

said first optical element and said light source are constituted by said OLED, said second optical element being constituted by a semi-reflecting screen interposed between said OLED and said space to be illuminated;

said screen is substantially plane while said OLED is bulged outwards so that its external face facing said screen and said space to be illuminated is convex;

said OLED is substantially flat while said screen is bulged inwardly so that its inner face facing said OLED and opposite said space to be illuminated is convex;

said screen has, opposite the electroluminescent peripheral zone of said OLED, a non-reflecting transparent zone so that a portion of the light rays emitted by said OLED is transmitted directly towards said space to be illuminated without encountering said semi-reflecting surface;

said first optical element is constituted by a reflector, and in that said second optical element and said light source are constituted by said OLED interposed between said reflector and said space to be illuminated;

said reflector is substantially plane while said OLED is curved inwardly so that its inner face facing said reflector and opposite said space to be illuminated is convex; said OLED is of flexible type and in that it furthermore comprises electromechanical means capable of cooperating with at least a portion of said OLED in order to modulate its shape and generate luminous animations; and or

a first edge of said OLED is fixed while said electromechanical means comprise an actuator comprising a piston movably mounted to slide in a liner and whose free end protruding from said liner is coupled to a second edge of said OLED, opposite said first fixed edge.

The invention also aims, in a second aspect, an optical signaling unit comprising such a light device.

Brief description of the drawings

The description of the invention will now be continued by the detailed description of an exemplary embodiment, given below by way of illustration but without limitation, with reference to the appended drawings, in which:

- Figure 1 is a schematic representation in vertical longitudinal section of a light device according to a first embodiment of the invention;

FIG. 2 represents an elevational view of the device of FIG. 1 when it is under tension, illustrating the illuminated appearance of this device and the three-dimensional optical effect;

FIG. 3 is a schematic representation in vertical longitudinal section of a light device according to a second embodiment of the invention; and

- Figure 4 is a schematic representation in vertical longitudinal section of a light device according to a third embodiment of the invention. Detailed description of an embodiment

FIG. 1 represents a signaling light device 1 according to a first embodiment of the invention, mounted in a lateral housing provided at the front or at the rear of an unillustrated vehicle.

The device 1 is arranged so as to emit a signaling light beam towards a space to be illuminated situated above this device according to the orientation of this FIG. 1 and corresponding in practice to a generally horizontal direction towards the front or towards the rear of the vehicle depending on its location.

This light device 1 comprises an organic light-emitting diode (OLED for "Organic Light Emitting Diode" in English) and a semi-reflecting screen 20 housed in a housing 30 provided with mechanical fastening means and unrepresented electrical connection means allowing to ensure its coupling to another structure of the vehicle such as a front or rear optical signaling unit for a motor vehicle.

OLED 10, flexible type (FOLED for "Flexible Organic Light Emitting Diode" in English) consists of the superposition of the following different layers:

a flexible transparent substrate 11 oriented towards the screen 20 and the area to be illuminated, this substrate being advantageously made of a plastic such as polyethylene terephthalate (PET) or glass and intended to ensure the mechanical stability of the OLED;

a first transparent electrode layer forming the anode 12 and composed of indium-tin oxide (ITO);

an organic layer structured in the present case into a non-active (i.e. non-electroluminescent) transparent central core area 13A and an active peripheral zone (i.e. electroluminescent) 13B; and

- A second electrode layer forming the cathode 14 and whose upper surface in the orientation of Figure 1 or more precisely that facing the organic layer is reflective. The active peripheral zone 13B of the organic layer, which here has a substantially rectangular shape, is conventionally constituted by the superposition of thin organic sub-layers typically comprising a Hole Transport Layer (HTL). an emitting sublayer (EL for "Emission Layer" in English) containing a dye and an electronically conductive sub-layer (ETL for "Electron Transport Layer" in English). By applying a suitable electrical voltage, electrons and holes are injected into the EL layer from the cathode and the anode. The electrons and holes drift toward each other and combine in this EL layer to form excitons whose disintegration provides the excitation energy of the dye molecule causing its electroluminescence. The color of the light emitted depends on the energy difference between the excited state and the base state and can therefore be modified using other dye molecules.

The inactive central zone 13A is made of different materials of organic or inorganic type.

The transparent substrate 11 is also flexible so as to make the OLED 10 here flexible (FOLED for "Flexible Organic Light Emitting Diode" in English), this flexibility being obtained thanks to that of the plastic substrate such as polyethylene terephthalate (PET), even metal or glass.

As illustrated in FIG. 1, this OLED 10 is also curved outwardly so that its outer surface facing the screen 20 and the space to be illuminated is convex.

A first vertical lateral edge 10A of this OLED 10 is also fixed rigidly to the housing 30 via a support 31.

The light device 1 further comprises an electromechanical actuator 32 housed inside the housing 30 and connected here to a continuous electric motor or stepper not shown.

This actuator 32 comprises a piston 33 slidably mounted in a liner 34 fixed rigidly to this housing 30 and extending in a direction transverse to the vertical side edges

10A, 10B of the OLED 10.

The free end of this piston 33 protruding out of the jacket 34 is coupled to the vertical lateral edge 10B of this OLED 10 located opposite the fixed edge 10A.

The semi-reflecting screen 20, substantially plane, extends perpendicularly to the optical axis X of the OLED 10 above it

(according to the orientation of Figure 1 or more precisely between this OLED

10 and the space to illuminate) and at a distance from the latter.

The screen 20 and the OLED 10 form a cavity 2 delimited essentially by the convex outer surface of the OLED 10 and by the flat internal surface of this screen 20.

Due to the reflectivity of the cathode 14, the light rays emitted by the active peripheral zone 13B of the OLED 10 towards the bottom of the housing 30 (ie opposite the space to be illuminated) are reflected in the direction of its outer surface, so that all the light rays emitted by the active peripheral zone 13B of the OLED 10 penetrate into the cavity 2 in a main direction oriented towards the space to be illuminated.

Almost all of these light rays emitted by the OLED 10 thus come to meet the internal surface of the semi-reflective screen

20.

A portion R1 of the rays R striking this screen 20 is transmitted to the space to be illuminated and forms a first image. The other part R ₂ of these light rays is reflected by the screen 20 towards the OLED 10. A portion of these reflected rays R ₂ passes through the main non-active transparent zone 13A of the organic layer to the cathode 14 where it is reflected towards the screen 20. These light rays striking the screen 20 will then be partly transmitted to the space to be illuminated by forming a second image and partly reflected again by the screen 20 to OLED 10, and so on so as to form a multitude of images whose light intensity gradually decreases. Due to the outwardly bulging nature of the OLED 10, the light rays passing through the non-active transparent main zone 13A of the organic layer and reflected by the cathode 14 are progressively shifted towards the center of the cavity 2, so that generated virtual images form a series of concentric rectangles light, I _2, h situated in planes more and more distant from the observer, giving a three-dimensional optical effect.

In addition, the sliding drive of the piston 33 in one direction or the other makes it possible to vary the stress exerted on the vertical lateral edge 10B in order to modulate its shape and to generate stylistic luminous animations (for example, effects of waves) giving an original visual signature to the luminous device 1.

The displacement of the piston 33 of the actuator 32 is managed by a not shown control module housed in the light device 1 or outside the latter (this module may for example be integrated with the on-board computer of the vehicle and be in a purely software form or in a form that combines a hardware part with integrated circuits with a software part).

FIG. 3 represents a signaling light device according to a second embodiment of the invention.

In the following and in Figure 3, we kept the same references for the identical elements, while similar elements are given a bonus.

This light device is similar to the device 1 previously described except that the OLED 10 'is substantially flat while the semi-reflective screen 20' is domed inward so that its inner surface facing the OLED 10 'and opposite the space to be illuminated is convex.

The OLED 10 'which has a structure similar to that of OLED 10, is therefore always constituted by the superposition of the following different layers:

a flexible transparent substrate 1 oriented towards the screen 20 'and the zone to be illuminated; a first transparent electrode layer forming the anode 12 ';

an organic layer structured in this case into a non-active transparent central main zone 13A 'and an active peripheral zone 13B'; and

- A second electrode layer forming the cathode 14 'and whose upper surface (in the orientation of Figure 2) or more precisely that facing the organic layer is reflective.

The screen 20 'and the OLED 10' form a cavity 2 'delimited essentially by the substantially flat outer surface of the OLED 10' and by the convex inner surface of this screen 20 '.

This second embodiment makes it possible to obtain substantially the same type of three-dimensional optical effect as that obtained with the first embodiment.

According to non-illustrated embodiments of these first two embodiments, the screen has, opposite the light emitting peripheral area of the OLED, a non-reflective transparent area such that a portion of the light rays emitted by said OLED are transmitted directly to the space to be illuminated without encountering the semi-reflective surface of this screen.

According to other variants of embodiment not shown, the OLED is of rigid type and the device is devoid of electromechanical means such as the actuator 32.

According to still other embodiments not shown, these electromechanical means are of different type and comprise for example an actuator with a piston that can be expanded or compressed by piezoelectric or electrostrictive effect depending on the materials used. The actuator can also be based on other principles such as electromagnetism or the joule effect.

According to still other embodiments not shown, the light device further comprises a second electromechanical actuator coupled to the lower or upper edge of the OLED while the opposite edge is rigidly fixed to the housing. Figure 4 shows a signaling light device 1 "according to a third embodiment.

In the following and in FIG. 4, the same references as in FIG. 3 have been kept for the elements that are identical to the second embodiment, whereas the similar elements are covered with a double premium.

In this embodiment, the rigid OLED 10 "takes the place of the semi-reflective screen 20 ', while a planar reflector 40 replaces the OLED 10'.

The OLED 10 "therefore extends above this reflector 40 in the orientation of FIG. 4 or more precisely between this reflector 40 and the space to be illuminated, and is further curved inwards so that its internal surface facing the reflector 40 and opposite the space to be illuminated is convex.

The upper surface of the reflector 40 in the orientation of Figure 4 or more precisely that facing the OLED 10 "(and the space to be illuminated) is reflective.

The OLED 10 "and the reflector 40 form a cavity 2" delimited essentially by the flat outer surface of the reflector 40 and the convex inner surface of this OLED 10 ".

The OLED 10 "has a structure substantially different from that of the OLEDs 10 and 10 '.

It is thus constituted by the superposition of the following different layers:

a flexible transparent substrate 11 "oriented in the direction of the zone to be illuminated;

a first transparent electrode layer forming the anode 12 "and whose lower surface (in the orientation of FIG. 4) or more precisely that facing towards the organic layer is semi-reflective.

an organic layer structured in this case into a non-active transparent central main zone 13A "and an active peripheral zone 13B"; and a second transparent electrode layer forming the cathode 14 ".

It will be noted in particular that the anode 12 "is now semi-reflective while the cathode 14" becomes transparent.

Due to the semi-reflective nature of the anode 12 ", the light rays emitted by the active peripheral zone 13B" of the OLED 10 "towards the space to be illuminated are partially transmitted towards this space without being reflected by forming a first image while the rest is reflected towards its inner surface.

Most of the light rays emitted by the active peripheral zone 13B "of the OLED 10" thus meet the reflector 40 and are reflected towards the OLED 10 ".

A portion of these reflected rays passes through the main non-active transparent zone 13A "of the organic layer to the semi-reflective anode 12" where it is partly transmitted to the space to be illuminated by forming a second image and partly reflected to the reflector 40, and so on so as to form a multitude of virtual images forming a series of concentric light rectangles located in planes further and further away from the observer.

The device according to the invention 1 may for example be used to ensure alone (or in combination with other complementary light device) the position light function (or lantern) whose light output required by the regulations is low.

Of course, the present invention is not limited to the embodiments described and shown, but encompasses any other embodiment.

Claims

A luminous signaling device for a motor vehicle capable of illuminating a space, said device comprising a first optical element (10; 10 '; 40) having a reflecting surface, a second optical element having a semi-reflecting surface ( 20, 20 ', 10 ") and arranged opposite and at a distance from said first optical element (10; 10'; 40) so as to define therebetween a cavity (2; 2 '; 2"), a light source (10; 10 '; 10 ") arranged to emit light rays penetrating into said cavity (2; 2'; 2"), a portion of these light rays being successively reflected by one and the other of said optical elements; (10, 20; 10 ', 20'; 10 ", 40) so as to generate a repetitive optical effect of depth;

one of said optical elements and said light source being constituted by an organic light-emitting diode (OLED) (10; 10 '; 10 ") comprising interposed between two electrodes (12, 14; 12', 14 '; 12", 14); ") of which one (14; 14 '; 12") constitutes said reflecting surface or said semi-reflecting surface, an organic layer (13A, 13B; 13A', 13B '; 13A ", 13B") structured in a zone main transparent non-electroluminescent center (13A, 13A ', 13A ") and in a light-emitting peripheral area (13B, 13B', 13B"), characterized in that said OLED (10; 10 ') is of flexible type and in that it further comprises electromechanical means (32) adapted to cooperate with at least a portion (10B) of said OLED (10; 10 ') to modulate its shape and generate light animations.

2. Signaling light device according to claim 1, characterized in that said first optical element and said light source are constituted by said OLED (10; 10 '), and in that said second optical element is constituted by a semicircular screen. reflective (20; 20 ') interposed between said OLED (10; 10') and said space to be illuminated.

3. Signaling light device according to claim 2, characterized in that said screen (20) is substantially planar while said OLED (10) is outwardly curved so that its outer face facing said screen (20) and said space to be illuminated is convex.

4. Signaling light device according to claim 2, characterized in that said OLED (10 ') is substantially flat while said screen (20') is domed inwardly so that its inner face facing said OLED (10 ') ') and opposite said space to be illuminated is convex.

5. Illuminated signaling device according to one of claims 2 to 4, characterized in that said screen (20; 20 ') has, opposite the electroluminescent peripheral zone of said OLED (10; 10'), a transparent zone non-reflective so that a portion of the light rays emitted by said OLED (10; 10 ') is transmitted directly to said space to be illuminated without encountering said semi-reflective surface.

6. Signaling light device according to claim 1, characterized in that said first optical element (40) is constituted by a reflector, and in that said second optical element and said light source are constituted by said OLED (10 ") interposed between said reflector (40) and said space to be illuminated.

7. Signaling light device according to claim 6, characterized in that said reflector (40) is substantially plane while said OLED (10 ") is curved inwardly so that its inner face facing said reflector (40) and opposite said space to be illuminated is convex.

8. Signaling light device according to one of claims 1 to 7, characterized in that a first edge (10A) of said OLED (10; 10 ') is fixed, and in that said electromechanical means comprise an actuator ( 32) comprising a piston (33) slidably mounted in a liner (34) and whose free end projecting from said liner (34) is coupled to a second edge (10B) of said OLED (10; 10 '), opposite said first fixed edge (10A).

9. Optical signaling unit of a motor vehicle characterized in that it comprises a light device according to one of claims 1 to 8.