The scope of the present invention is that of light projectors and, more particularly, the headlamps for motor vehicles.
Motor vehicle headlamps generally comprise at least one light source adapted to generate a light beam and means for controlling the shape of the light beam in order to adapt the latter to the circumstances of driving.
A projector may include two light sources, namely:
- a first light source which is intended to generate a first light beam corresponding to a low beam, the first light beam being lowered (that is to say not raised to the maximum with respect to the road) so as not to dazzle drivers traveling in the opposite direction (the vehicle equipped with said projector), said first light source by implementing a so-called short code; and

- a second source of light which is intended to generate a second light beam corresponding to a high beam, the second light beam being raised (relative to the low beam) to illuminate the road, this second light source implementing of a so-called drive.

Generally, the projector further comprises at least one electric leveling configured to act on a moving means, to cause the beam generated by a light source in a nominal position, for example in a so-called position code for the first source of said light. To this end, the range adjustment receives a control signal generated in the usual manner by a suitable control unit.

Regulation prohibits a range adjustment of this type, which is intended for a function code, to move the light beam towards a dazzling position.

However, in case of failure of correction, or for errors or loss of the control signal, the risk of glare turned out.

Moreover, the light sources include, but increasingly, LED type LED ( "Light Emitting Diode" in English). Such light emitting diodes are highly advantageous, but they have a reduced power.

The present invention aims to provide a motor vehicle light projector which allows to provide additional illumination and is particularly suitable for a light source provided with light emitting diodes while avoiding glare in case of failure.

To this end, according to the invention, said headlight for a motor vehicle, of the type comprising at least:

- a light source configured to generate a light beam; and

- moving means suitable for moving the light beam and to bring it at least in said nominal position,

is remarkable that comprises:

- an electric control can be controlled, said corrector being configured to act on the moving means at least in order to raise the light beam generated by the light source with respect to the nominal position and bring it into a said raised position, the corrector being controlled in accordance with a received electrical control signal;

- a sensing element implementing a detection function and configured to detect at least a loss of said control signal (in the raised position); and

- a control element implementing a protection function and configured to control the correction so that it causes the light beam (the raised position) in a lowered position known, which is more lowered than the raised position in the event of detecting loss of the control signal, without changing the behavior of the correction in case of short circuit on the control signal.

Preferably, the nominal position of the light beam corresponds to a so-called short code, and the raised position of the light beam corresponds to an assist position to a so-called drive, by implementing a so-called code statement.

Thus, thanks to the invention, the light beam can be raised with the correction and thus help the illumination of the road, preferably when the projector is to generate a high beam, by implementing a function code statement. This function code statement provides additional illumination to the road function, using said light beam nominally used for code function.

In addition, thanks to the sensing and control elements, one is able to prevent a potential glare problem with such code reading function in case of failure (loss of control signal), lowering in this if the light beam in a lowered position preventing dazzling drivers in oncoming, which avoids any risk of glare during such a failure.

In addition, according to the invention, while providing the security, it does not change much for the behavior of the correction in case of short circuit on the control signal.

To do this, the sensing element is also configured for detecting a short circuit on the control signal, and the control element is also configured to control the checker to freeze the position of the light beam at the position it has at the time of detection, in case of detection of a short circuit on the control signal, that is to say, a disconnection or breakage of the control wire

(Sending the control command in electrical form) which makes contact with a mass or a power supply.

The projector as described above, is suitable for any type of light source. However, in a preferred embodiment, the projector light source comprises at least one and preferably a plurality of light emitting diodes. The present invention makes it possible, in this case, to compensate, for the raised position, the low power light emitting diodes.

In the context of the present invention, the detection function implemented by the sensing element and the protection function (or corrective control) implemented by the control element may be realized by software ( "software" in English), for example as a data processing program and control signal generator which is integrated into an electronic card that is, for example, mounted in the corrector.

However, in a preferred embodiment of the invention, these functions are performed by hardware ( "Hardware" in English).

For this purpose, advantageously, said corrector comprises a control element ( "Driver IC" in English) provided with a functional input at low impedance and a high impedance monitoring input, and it is part of a electrical circuit comprising, in addition, arranged decoy resistance so as to provide on the monitoring input information causing the corrector to reduce the light beam in the lowered position.

Advantageously, the resistance to spoofing is arranged between the input of the control signal in the electrical circuit and a supply voltage point, so as to act on the input of high impedance of the electric control monitoring, connected to the input of the control signal.

Moreover, in a particular embodiment, the projector is configured to receive said electrical control signal from a control unit.

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 showing the main elements of a particular embodiment of a headlight according to the invention; and

- Figure 2 is a block diagram of a portion of an electrical circuit provided with a hardware-based correction.

The present invention applies to a motor vehicle headlight, configured to generate a light beam.

As shown very diagrammatically in Figure 1, the projector

1 includes at least a light source 2 which is intended to generate a light beam F corresponding firstly to a low beam. When used as a low beam, the light beam F is not raised to the maximum with respect to the road to avoid dazzling drivers traveling in opposite directions, and is brought into a position P0 in the usual operation, called nominal position, the direction of illumination is illustrated by a dashed arrow in Figure 1. In this case, the light source 2 implements the usual way, a so-called short code.

To do this, the projector 1 comprises a moving means 3, for example of optical type, adapted to move the light beam F in particular to bring it at least in said nominal position P0. The moving means 3 moves the light beam F by modifying its angular position, as shown by a double arrow E in Figure 1,

for varying the direction of illumination, downwardly or upwardly relative to the vertical shown by an arrow V.

In the present description, the terms top and bottom are defined with respect to the vertical direction, whose direction is shown by arrow V.

The projector 1 comprises, moreover, a corrector 4 range, of the electrical type. This corrector 4 of reduced cost, is configured to act in the usual manner, as schematically illustrated by a link 5 in phantom, the moving means 3 (via a management command for example), to at least be able to raise the beam light F generated by the light source 2 relative to the nominal position PO and bringing it into a said raised position P1 position.

To this end, the corrector 4 is controlled in accordance with an electric control signal, received via an electrical connection 6 to a control unit 7. The control unit 7 is, for example, installed in the vehicle interior with the projector 1 and is actuatable by the vehicle driver.

The nominal position PO of the light beam F corresponds to a so-called short code, and the raised position P1 of the light beam F corresponds to an assist position to a so-called drive, to which is thus implementing a function known as code statement.

Furthermore, the projector 1 further comprises:

- a sensing element 8 implementing a detection function and configured to detect at least a loss of said control signal generated by the control unit 7, when the implementation of the code reading function; and

- a control member 9 which is, for example, connected to the sensor element 8 (as shown by a Naisonl O), which implements a protection function (or corrective control), and which is configured to control the corrector 4 so that it causes the light beam F (via the moving means 3) in said lowered position P2 position, upon detection of a loss of the control signal by the control member 8 at the implementation of the code reading function. This lowered position P2 is lowered (vertically) than the raised position P1, that is to say, the light beam is emitted in a direction which is less high relative to the vertical V, and is set to prevent a glare , including drivers of vehicles traveling in the opposite direction to the vehicle equipped with said projector 1.

In addition, the control member 9 is configured not to change the behavior of the corrector 4 in case of short circuit on the control signal.

Thus, the light beam F can be raised using the corrector 4 (via the moving means 3) and thereby assist in the illumination of the road, preferably when the projector is to generate a high beam, by setting implement a so-called statement code. This code reading function and provides additional illumination to the beam to implement the road function.

In addition, thanks to the sensing and control elements, one is able to prevent a potential glare problem with such code reading function in case of failure (loss of control signal), lowering in this if the light beam F to bring it to the lowered position P2 (glare), which avoids any risk of glare during such a failure.

The projector 1 as described above, and enables regulatory compliance of a function code statement without creating glare situation.

In addition, while providing this security is not provided however altering the behavior of the corrector 4 in case of short circuit on the control signal, in a usual operation (for which the code reading function is not enabled).

To do this :

- the sensor element 8 is also configured for detecting a short circuit on the control signal; and

- the control member 9 is configured to control the equalizer 4 so that it freezes the light beam position F to the position it had at the time of detection (sensing element 8) of a short -Circuit on the control signal out survey code position. Such a short circuit corresponding to a disconnection or breakage of the wire (or control link 6) which transmits the control command in electrical form. In this case, the wire will be put in contact with a mass or optionally with a power supply (e.g. 12V).

Therefore, the projector 1 is thus configured to implement the following actions:

- fold the light beam F to a lowered position P2 in the event of loss of the control signal;

- freeze the corrector 4 in case of short circuit at a potential of 0V on the control signal (disconnection of the control wire from getting in touch with a weight); and

- freeze the corrector 4 in case of short-circuit to a power potential on the control signal (disconnection of the control wire from getting in touch with a power supply (e.g. 12V)).

In the example of Figure 1, the sensor element 8 and the control member 9 are incorporated in the corrector 4.

The projector 1 as described above, is suitable for any type of light source 2. However, in a preferred embodiment, the light source 2 comprises at least one and preferably a plurality of LEDs 1 1. The present invention thus makes it possible in particular to overcome, by the raised position P1, the low power light emitting diodes 1 January.

In the context of the present invention, the implementation detection function by the detection element 8 and the protection function setting

implemented by the control member 9 may be realized by software ( "software" in English), for example as a data processing program and generating control signals. Such a program may, for example, be integrated into a circuit board which is mounted in the corrector 4.

However, in a preferred embodiment of the invention, these functions are performed by hardware ( "Hardware" in English).

In this preferred embodiment, shown partially and schematically in Figure 2, the electric control 4 comprises a drive member 12 provided with a functional input 13 at low impedance and a monitoring input 14 at high impedance. The inlet 13 is the functional input acting on the basic performance of the steering adjuster. This control element 12 is part of an electrical circuit 15.

As an illustration, the control element 12 ( "IC Driver" in English) can be of conventional type and TLE 4206-2G it has two pins (both) affecting the control signal:

- a pin (or input) 13 as functional low impedance; and

- a pin (or input) monitoring 14 high impedance

The electrical control circuit 15 comprises, in particular, a R1 reference resistor connected to the functional input 13 and a resistor R2 connected to the monitoring input 14.

Moreover, on the part of the electrical circuit 15 shown in Figure 2, there is also shown:

- an inlet 16 of the control signal, related for example to the connection 6 of Fig 1;

- a power supply voltage VA, which is linked, via a diode 17 to a power supply input 18 of the control element 12; and

-an output 19 of the control element 12, the value (control command) provided at the output 19 is transmitted via a link 20.

The electrical circuit 15 further comprises a resistor R3 decoy. This resistor R3 decoy is arranged to provide on the monitoring input 14 information causing the corrector 4 to lower the light beam F in the lowered position P2.

Resistance decoy R3 is arranged between the input 16 of the control signal in the electric circuit 15 and a point 21 of supply voltage, so as to act on the monitoring input 14 high impedance electrical corrector 4, which is connected to the input 16 of the control signal.

Such an arrangement of the resistor R3 decoy used to modify the behavior of the monitoring pin 14 without changing the behavior of the functional pin 13.

The value of the resistor R3 decoy is determined in a standard manner, so as to:

- fold the beam to a predetermined position in case of loss of the control signal;

- freezing the correction during a short-circuit at a potential of 0V on the control signal, in case of disconnection of the control wire from getting in touch with a ground;

- freezing the correction during a short circuit to a power potential on the control signal, in case of disconnection of the control wire from getting in touch with a supply voltage + VA (12V for example).

The projector 1 including the electric circuit 15, as described above, and allow, from a corrector 4 comprising a control element 12 of the type "Driver" performing the solidification of the corrector 4 in case of incident beam (loss of the control signal, short circuit of the control signal with a ground and a power or e.g. de12V) according to regulations, to operate the steering member 12 so as to obtain a folding of the light beam in case loss of the control signal in the case of the addition of a code reading function.

More specifically, the aforementioned characteristics and in particular the addition of resistor R3 decoy used to modify the electrical circuit 15 so that it passes from a first mode of conventional control to a second control mode according to the invention. The first mode of conventional control is not to generate motion of the power incident on the vehicle, such as loss of the control signal, a short circuit between the control signal and the power source and a short -Circuit between the control signal and ground. The second control mode of the invention, it is to lower the beam in the case of a control signal loss without changing the behavior (no lifting beam) in case of short circuit between the control signal and the power source and short-circuit between the control signal and ground.

The preferred embodiment described above in reference to Figure 2, in particular the following advantages:

- it is only type materials (resistance decoy R3, pilot member 12, ...);

- it requires no software for its implementation;

- it does not affect the basic functionality as the functional input 13 is low impedance; and

- it has no impact on other regulatory issues.

CLAIMS
1. Headlight for a motor vehicle, said headlight (1) comprising at least:
- a light source (2) configured to generate a light beam (F);
- a moyen de deplacement (3) apte to the reden faisceau lumineux (F) and the amener au moins dans une position say nominal (PO); and

- a corrector (4) power can be controlled, said corrector (4) being configured to act on the moving means (3) in order at least to increase the light beam (F) generated by the light source (2) relative to the nominal position (PO) and bring it into a said raised position (P1), the corrector (4) being controlled as a function of an electrical control signal received,

characterized in that it further comprises:

- a sensing element (8) implementing a function of detecting and configured to detect at least a loss of said control signal; and

- a control element (9) implementing a protection function and configured to control the equalizer (4) so ​​that it causes the light beam (F) from the raised position (P1) in said lowered position (P2) which is more lowered than the raised position (P1) in case of detecting a loss of the control signal,

the sensing element (8) also being configured for detecting a short circuit on the control signal, and the control element (9) also being configured to control the equalizer (4) so ​​that it fixes the position of the light beam (F) to the position it had at the time of detection, in case of detection of a short circuit on the control signal.

2. A projector according to claim 1,

characterized in that the nominal position (P0) of the light beam (F) corresponds to a so-called short code, and the raised position (P1) of the light beam (F) corresponding to an assist position to a so-called drive .

3. Headlight according to one of the preceding claims,

characterized in that the light source (2) comprises at least one light emitting diode (1 1).

4. Headlamp according to any one of the preceding claims, characterized in that said corrector (4) comprises a control element

(12) provided with a functional input (13) under a low impedance and a monitoring input (14) at high impedance, and in that it is part of an electric circuit (15) further comprising, decoy resistance (R3) arranged to provide on the monitoring input (14) causing the correction information (4) lowering the light beam in the lowered position (P2).

5. A projector according to Claim 4,

characterized in that the decoy resistance (R3) is arranged between the inlet (16) of the control signal in the electrical circuit (15) and a feed voltage point (21), so as to act on the monitoring input (14) at high impedance corrector (4) electrically connected to the input (16) of the control signal.

6. A projector according to any preceding claim, characterized in that it is configured to receive said electrical control signal from a control unit (7).