The scope of the present invention is that of light projectors and, more particularly, the headlamps for motor vehicles.
Motor vehicle headlamps usually comprise an illumination system that generates and projects light on a reflector. The light is then sent to a lens to be reversed and returned as a light beam outside of the vehicle.
It is known that it may be necessary to limit the scope of such a projector during movement of the motor vehicle, in particular to limit the scope of the projector to the low beam in order to avoid dazzling other drivers oncoming .

In addition, an advanced lighting can be provided not illuminate certain specific parts of the lighting area could be illuminated by the lighting system, for example an area portion in which is located a vehicle from front or wherein there is an object, such as a reflective panel, which is not desired to illuminate.

We know different standard solutions to adapt the shape of the light beam to the circumstances of the conduct.

A first solution, mainly mechanical, is to use in the lighting system, a switching mechanism that allows to hide (or not) a part of the reflected beam. Usually, such a switching mechanism generally comprises a rotatable disconnecting strip. The disconnecting strip is electrically actuated to move, on command, between two or more angular positions in which it conceals more or less the light beam.

This first mechanical solution that is effective and low cost, has the disadvantage of not being able to conceal a limited number of areas.

To overcome this drawback, a second usual solution is known, mainly of optical type, which is configured to generate a matrix based beam ( "Matrix Beam"). Such a display system uses a matrix comprising a high number of LED type light emitting diode (or "LED" to "Light-Emitting Diode" in English). This lighting system allows, for selective ignition and extinction of said light emitting diodes, not to illuminate one or more parts of the illumination region adapted to be covered by the illumination system.

With such an illumination system, it is possible to achieve dynamic lighting comprising a plurality of non-illuminated zones, or reduced lighting, with a precise location, corresponding in particular to the position of vehicles oncoming or preceding vehicle the motor vehicle equipped with the lighting system.

However, the illumination system of this second solution has the disadvantage of requiring a high number of light emitting diodes, generally of the order of 20 to 80, which generates a high cost. In addition, in this second solution, it is expected generally to use laser diodes, the technology is not completely mature, and in any case less mature than those of conventional LEDs.

The present invention aims to provide a display system which, while allowing to implement a light-based LEDs, does not have the drawbacks, including cost, the aforementioned second conventional solution.

The invention relates to a lighting system for a motor vehicle headlight, the illumination system comprising:

- at least one light source comprising at least one electroluminescent diode, said light source being configured to be turned on and off and being adapted to generate light radiation when activated;

- at least one focusing means; and

- at least a scanning device receiving the light radiation generated by the light source and transmitted by the focusing means, the scanning means comprising at least one system of reflection, rotatable, and a movement formatting unit of the system reflection, the scanning device being configured to reflect the light radiation and distribute the spatially emitting a light beam.

According to the invention, at least said light source is configured to a light beam of substantially rectangular general shape, oriented in a first so-called vertical direction, is issued, the scanning device is configured to perform a scanning of the light beam shape substantially rectangular in a second horizontal direction called general, which is substantially orthogonal to said vertical direction, said scanning being performed at a rate to get a persistence of vision, and an activation command / deactivation of the light source is synchronized with scanning the scanning device.

Thus, through the generation of a vertical light beam of rectangular shape, associated with horizontal scanning, it is able to provide a lighting of an area of ​​usual overall lighting of a motor vehicle headlight, while using a reduced number of light emitting diodes, which reduces the cost compared with the aforementioned second conventional solution.

Parts of unexposed areas (or at least having a reduced lighting) are obtained by synchronizing the termination of the light beam with its scanning, that is to say, by turning off the light source when, during scanning the light beam is supposed to be a part of area that you want does not illuminate.

For the implementation of the invention, the scanning of the rectangular light beam is performed at high speed in order to benefit of retinal persistence, that is to say so that the human eye sees a entire area illuminated despite the sweep. Persistence of vision is a phenomenon attributed to the human eye an afterimage on the retina, usually for a period of about 1/25 of a second.

For this purpose, advantageously, the movement formatting unit is configured to generate an angular speed of scanning very high and higher, preferably at 3000 ° per second.

Advantageously, the light source comprises a plurality of light emitting diodes arranged to form a plurality of diodes having a rectangular shape.

In addition, advantageously, the reflection system is movable about an axis parallel to said vertical direction.

Moreover, in a first embodiment, the reflection system is configured to perform a complete rotational movement. In this case, preferably, the reflecting system has a cylindrical shape provided on its outer periphery with a plurality of mirrors arranged one next to the other around the periphery.

Further, in a second embodiment, the reflection system is configured to perform an oscillatory rotary motion in a given angle of rotation smaller than 180 °.

Moreover, advantageously, the movement setting unit may include:

- a DC brushless motor; or

- a piezoelectric motor.

The present invention also relates to a headlight for a motor vehicle comprising at least one illumination system, such as that described above.

The present invention further relates to a control method of such a lighting system for a motor vehicle headlight.

According to the invention, said method comprises a control step of synchronizing the activation / deactivation of the light source with the scanning of the scanning device so as to disable if necessary the light source for at least one given position of the emitted light beam to obtain at least one non-illuminated portion in a lighting area (covered by the illumination system).

The invention will be better understood and other objects, details, characteristics and advantages thereof will appear more clearly during the detailed explanatory description which follows, embodiments of the invention given as an example purely illustrative and non limitative, with reference to the accompanying diagrammatic drawings. In these drawings:

- Figure 1 is a block diagram of an illumination system according to a first embodiment;

- Figure 2 is a graph for illustrating the scanning of a light beam;

- Figure 3 schematically shows an exemplary embodiment of a light source comprising a plurality of light emitting diodes;

- Figures 4 and 5 are schematic views, respectively in perspective and top plan view of an exemplary embodiment of the illumination system according to the first embodiment; and

- Figure 6 is a block diagram of an illumination system according to a second embodiment.

The present invention is applicable to a projector (not shown) of a motor vehicle, configured to generate a light beam. This projector comprises an illumination system 1 as shown schematically in Figure 1.

This lighting system 1 is mounted within a housing (not shown) of the projector, in front of a protective lens, for emitting a light beam directed towards the road scene situated in front of the motor vehicle.

As shown schematically in Figure 1, the illumination system 1 comprises:

- a light source 2 comprising at least one LED 3 LED type (or "LED" for "Light Emitting Diode" in English). The light source 2 is configured to be activated and deactivated, that is to say, it can be controlled in order to turn on or off or the light emitting diodes 3, and is adapted to generate light radiation R when activated, with said one or more light emitting diodes 3;

- focusing means 4 (lens), in the focal plane of which is arranged the light source 2; and

- a scanning device 5A, 5B, which receives the light radiation R generated by the light source 2, the reflected and distributes spatially emitting radiation (said light beam F in the context of the present invention) which is projected to the outside the projector.

The scanning device 5A, 5B comprises at least one reflection system 6A, 6B to move in rotation, and a movement formatting unit 7A, 7B configured to move the reflection system 6A, 6B, as shown by an arrow 8A, 8B in phantom lines in figures 1 and 6.

The numerical references to which is associated the letter A relate to a first embodiment of the scanning device shown in Figure 1, while reference numerals to which is associated the letter B relate to a second embodiment shown in Figure 6.

According to the invention:

- said at least one light source 2 is configured to a light beam F having a substantially rectangular general shape, is issued, as shown in Figure 2. This light beam F is directed (by its length) in a first so-called vertical direction Z ;

- the scanner 5A, 5B is configured to perform a scanning of the light beam F (substantially rectangular general shape) in a second direction said horizontal Y, which is substantially orthogonal to said vertical direction Z, as shown by an arrow B Figure 2. the scanning is carried out between two extreme positions P1 and P2 shown in thin continuous lines. In the projector mounted position on the motor vehicle, the Z direction corresponds substantially to the vertical direction relative to the ground and the Y direction corresponds substantially to a horizontal direction transverse to the motor vehicle;

- scanning is performed at a high speed which is such that it allows a human eye to benefit from retinal persistence, as specified below; and

- controlling activation / deactivation of the light source 2 is synchronized with the scanning produced by the scanner 5A, 5B.

Thus, through the generation of a light beam F vertical (in the Z direction) of rectangular shape, combined with a horizontal scan (in direction Y) of the light beam F, the illumination system 1 is able to provide a lighting of an area of ​​usual overall lighting (laterally delimited by the positions P1 and P2 of Figure 2) of a motor vehicle headlight, while using a reduced number of light emitting diodes, preferably from 1 to 8 emitting diodes.

The lighting system 1 and has a reduced cost, especially since one can use conventional light emitting diodes (not laser) which are cheaper.

The illumination system 1, as described above, is able to create in the illumination zone one or more portions of non-illuminated area (or having at least a reduced lighting). This or these area portions are obtained by synchronizing the termination of the light beam F at the light source 2 with its scanning, that is to say, by turning off the light source 2 at the time, during scanning, the light beam F is supposed to be in some area that you want does not illuminate as shown in some of zone Z1 in Figure 2. This section zone Z1 shown in phantom includes two positions P2 and P3 side successive rectangular F of the light beam.

The lighting system 1 is able to create in the illumination region a plurality of portions of different area, non-illuminated (or at least having a reduced light), thereby generating a dynamic and selective lighting.

For the implementation of the invention, the scanning of the rectangular light beam is directed at high speed in order to benefit from a persistence of vision, that is to say so that the human eye sees an entire area illuminated despite the sweep.

To do this, the last moving unit 7A, 7B is configured to generate a movement of the reflection system 6A, 6B creating an angular speed of scanning very high and higher, preferably at 3000 ° per second.

Illustratively, with a 100Hz frequency sweep speed to an angular range of 40 °, one obtains an angular velocity of 4000 degrees per second.

The lighting system 1 is associated with a control unit (not shown) which controls the timing of activation / deactivation of the light source 2 with the scanning of the illumination device 5, by generating conventional manner orders appropriate command that are sent to the light source 2 (and possibly the movement formatting unit) according to the angular position of the emitted light beam.

Information concerning not only parts of area to be illuminated, which are used to determine these control commands are generated in the usual manner, for example using an approaching vehicle detection camera. The acquisition of this information is not within the context of the present invention and is not described further.

In a preferred embodiment shown in Figure 3, the light source 2 comprises a plurality of LEDs 3 arranged to form a diode array 9 having a rectangular shape.

In the example shown in Figure 3, all diodes 9 comprises five light emitting diodes 3 of square shapes identical. In this example, the length L of the diode array 9 is thus equal to five times its width /.

In this preferred embodiment, the rectangular shape of the emitted light beam F is created by the rectangular shape of the light source 2 generates light radiation R.

However, in the context of the present invention, the light beam of rectangular shape F can be created in various ways, in particular by a particular combination of light source (diode (s) emitting (s)) and means optical shape generation (not shown).

The reflection system 6A, 6B is movable about an axis X which is parallel to said vertical direction Z.

In a first embodiment shown in Figures 1, 4 and 5, 6A reflection system is configured to perform a complete rotary movement, for example in the direction shown by an arrow A in Figure 1.

In this case, the reflection 6A system comprises a cylindrical part 10, having a symmetry of revolution about the axis X, which is provided on its outer Peripherals overview 1 1 of a plurality of mirrors 12 (for example eight or sixteen mirrors ), arranged one next to the other around the periphery (or circumference). This cylindrical part 10 is rotated by the setting in motion unit 7A.

During the rotation of the reflection system 6A, light radiation R is reflected in succession, one after the other, by the mirrors which are arranged one beside the other, and at each instant by the mirror which is a PO position in front of the focusing means 4. Moreover, because of the rotation of 6A reflection system which changes the relative position of the mirror (performing reflection) with respect to the direction E of transmission of radiation R light, the direction D of emission of the light beam F varies. This direction is at an angle of angular field which preferably has a value of 40 ° or 60 °, that is to say with values ​​+/- 20 ° or +/- 30 ° in side of a central angular position.

Sample of Figures 4 and 5, does not show the unit of moving resulting in the reflection system 6A. However, these Figures 4 and 5 show a radiator 13 for cooling the light source 2 provided with a light emitting diode 3.

Further, in a second embodiment, shown schematically in Figure 6, the reflection system 6B includes a mirror 14 and is configured to perform an oscillatory rotational movement under the action of the movement formatting unit 7B in an angular range given, less than 180 °, for example in an angular range of 40 °.

In the context of the present invention, the movement formatting unit 7A, 7B may comprise any type of motor capable of implementing the rotational movement or oscillation considered. In a particular embodiment, it may include:

- a DC brushless motor; or

- a piezoelectric motor.

The operation of the illumination system 1, as described above, is as follows.

The illumination system 1 generates, using at least the light source 2, a vertical light beam F (the Z direction) of rectangular shape. Simultaneously, the scanner 5A, 5B performs a horizontal scanning of the light beam F vertical, in the direction Y.

The lighting system 1 and sends a light of a usual overall illumination area of ​​a motor vehicle headlight.

Scanning the rectangular light beam F is performed at very high speed in order to benefit from retinal persistence.

In addition, the illumination system 1 synchronizes activation and deactivation of the light source 2 with the scanning of the scanning device 5A, 5B, so as to disable if necessary the light source 2 for at least one given position of the beam emitted light, to obtain at least a non-illuminated portion in an illumination area. The lighting system 1 and generates a controllable dynamic lighting.

CLAIMS
1. Lighting system for a motor vehicle headlight, the illumination system (1) comprising:
- at least one light source (2) comprising at least one light emitting diode (3), said light source (2) being configured to be turned on and off and being adapted to generate light radiation (R) when activated;

- at least one focusing means (4); and

- at least one scanning device (5A, 5B) receiving the light beam (R) generated by the light source (2) and transmitted by the focusing means (4), the scanning device (5A, 5B) comprising at least a reflection system (6A, 6B) movable in rotation and a unit (7A, 7B) for moving the reflection system (6A, 6B), the scanning device (5A, 5B) being configured to reflect the light radiation (R) and the spatially spread by emitting a light beam (F),

at least said light source (2) being configured to a light beam (F) of substantially rectangular general shape, oriented in a first direction (Z), called vertical, or emitted, the scanning device (5A, 5B) being configured to effect a scan of the light beam (F) of substantially rectangular general shape in a second direction (Y) called horizontal, that is substantially orthogonal to said vertical direction (Z), said scanning being performed at a rate to get a retinal persistence, and an activation control on / off the light source (2) being synchronized with the scanning of the scanning device (5).

2. An illumination system as claimed in claim 1,

characterized in that the control of activating / deactivating the light source (2) is synchronized with the scanning of the scanning device (5A, 5B) so as to turn off the light source (2) for at least a given position the light beam (F) emitted during scanning, in order to obtain at least a non-irradiated region (Z1) in an illumination area of ​​the illumination system (1).

3. An illumination system according to one of claims 1 and 2,

characterized in that the light source (2) comprises a plurality of light emitting diodes (3) arranged to form an assembly (9) diodes having a rectangular shape.

4. A lighting system according to any one of claims 1 to 3, characterized in that the reflection system (6A, 6B) is movable about an axis (X) parallel to said vertical direction (Z).

5. A lighting system according to any one of claims 1 to 4, characterized in that the reflection system (6A) is configured to perform a complete rotational movement.

6. An illumination system according to claim 5,

characterized in that the reflection system (6A) comprises a cylindrical part (10) provided on its outer periphery (1 1) of a plurality of mirrors (12) arranged one next to the other around the periphery .

7. A lighting system according to any one of claims 1 to 4, characterized in that the reflection system (6B) is configured to perform an oscillatory rotational movement, within a given angle of rotation smaller than 180 °.

8. A lighting system according to any one of claims 1 to 7, characterized in that the unit for moving (7A, 7B) comprises a DC brushless motor.

9. A lighting system according to any one of claims 1 to 7, characterized in that the unit for moving (7A, 7B) comprises a piezoelectric motor.

10. An illumination system according to any preceding claim,

characterized in that the unit for moving (7A, 7B) is configured to generate an angular speed of scanning over 3000 ° per second.

January 1. Headlight for a motor vehicle,

characterized in that it comprises at least one illumination system (1) such as that specified under any one of claims 1 to 10.

12. A method of controlling a lighting system for a motor vehicle headlight according to any one of claims 1 to 10,

characterized in that it comprises a control step of synchronizing the activation / deactivation of the light source (2) with the scanning of the scanning device (5A, 5B) so as to disable if necessary the light source (2) for at least one given position of the light beam (F) emitted in order to obtain at least a non-irradiated region (Z1) in an illumination area ..