FR2891430A1 - Lighting and/or signaling device e.g. side marker light, for motor vehicle, has six diodes of which three diodes emit detection light beam reflected by obstacle and other three diodes detect reflected light beam - Google Patents

Abstract

The device has light emitting diodes (D1 - D6) that are provided as light sources and performing a light signaling function when the device is activated in a signaling mode. The diodes (D1 - D3) operate as a light beam emission unit and the diodes (D4 - D6) operate as a light beam reception unit, in a detection mode of the device. The diodes (D1 - D3) emit a detection light beam which is reflected by an obstacle in the form of a reflected detection light beam. The diodes (D4 - D6) operate as optic sensor and detect the reflected light beam, for delivering a measurement signal (SM).

Description

Light-emitting diode lighting and / or signaling device

  The invention relates generally to lighting and / or signaling devices intended to be mounted in motor vehicles. More particularly, the invention relates to lighting and / or signaling devices for a motor vehicle, incorporating a detection function and comprising at least one light-emitting diode (LED) as a light source.

  On-board active safety systems in motor vehicles are the subject of much research by automobile manufacturers and suppliers. In particular, driver assistance systems incorporating safety and comfort functions are currently undergoing major developments that result in a significant increase in onboard electronics in vehicles.

  On-board electronic systems are now able to provide a number of essential safety functions such as pre-crash (English pre-crash) and include obstacle detection and blind spot monitoring. Perimeter protection and parking assistance are also features of great interest.

  A major disadvantage of these prior art systems is the number and variety of sensors that are required as information-gathering means. Indeed, on the one hand, the understanding of the road scenes is a complex problem related to the variety of situations encountered and, on the other hand, these systems are not entitled to error and are therefore subject to a requirement of extreme reliability. This results in a proliferation of sensors of different types each having advantages and disadvantages.

  The sensors generally used by these systems are devices such as radar, laser range finder, video camera or ultrasonic sensor.

  Radar and laser rangefinders are expensive solutions and are also active sources of electromagnetic pollution sometimes not compatible with current regulatory constraints.

  Video cameras require detection algorithms that pose a number of problems, particularly in terms of speed of computation and robustness, related to the need for real-time detection of obstacles and a near-zero tolerance of false alarms.

  According to a first aspect, the present invention provides a lighting and / or signaling device for a motor vehicle, incorporating a detection function and comprising at least a first light-emitting diode as a light source. According to the invention, said first light-emitting diode, in addition to a light beam emission function required to provide the illumination and / or signaling provided by the device, also fulfills a function of optical detection of light beams.

  It will be noted here that the invention is based on the principle of the reversibility of LEDs. Indeed, any Led diode, usually dedicated to the emission of a light beam, is also able to function as an optical detector in a band close to its spectral range. Although the performance obtained for a detection operation is lower than that which can generally be provided by a dedicated optoelectronic sensor, the tests carried out by the inventive entity show that these performances are, however, sufficient for a large number of applications in the automotive field.

  The current powerful increase in the integration of light-emitting diodes in headlamps and traffic lights is an important advantage for the present invention. Indeed, thanks to the invention, it becomes possible to have a low cost of a large number of sensors operating on the entire periphery of the vehicle, given the presence of lighting / signaling devices both in the front and at the rear only on the sides (repeaters, for example) of the vehicle.

  The invention can be implemented in any lighting and / or signaling device using Led diode type light sources. In the devices according to the invention, in addition to their conventional use as light sources for lighting and signaling functions, the LED diodes can also be used in actual detection applications, such as the detection of light sources. external to the vehicle, or in more sophisticated applications, such as obstacle detection, requiring the emission of a light beam and the reception of a reflected light beam.

  Since a diode can not, of course, operate simultaneously in transmission mode and reception mode, it is provided according to the invention to allow the reception mode only during periods of inactivity of the Led diode, relatively to its main function of emission, or during brief time intervals, imperceptible to the human eye, during periods when it is activated in emission. The rise times of the LEDs used in the lighting and the automobile signaling are sufficiently low (less than 10 ns) to allow switching operation with such short time intervals.

  According to a particular characteristic of the invention, the device also comprises first electronic control means for controlling, during at least a first time interval, an operation of said first light-emitting diode in light beam emission for lighting and / or signaling and, during at least a second time interval, an operation of said first light emitting diode in optical detection of light beams; and electronic detection means connected to said first light emitting diode for receiving a measurement signal produced thereby in response to receiving a light beam during said second time interval and outputting detection information resulting from a processing of said light-emitting diode measurement signal.

  Preferably, said electronic control means comprise first switching means controlled during said second time interval for disconnecting a first power supply from said first light emitting diode; and second switching means controlled during said second time interval for connecting said electronic sense means to said first light emitting diode.

  In addition, said electronic detection means typically comprise amplification means and / or filtering means and / or demodulation means and / or threshold detection means.

  According to a particular embodiment suitable for obstacle detection, the device according to the invention also comprises at least one second light-emitting diode as a light source which also fulfills, in addition to a light beam emission function required to ensure the illumination and / or signaling provided by the device, a function for transmitting a detection light beam, at least a portion of which is capable of being reflected by an obstacle and detected by a said first light-emitting diode that fulfills said optical detection function of light beams.

  According to another characteristic, the device according to the invention also comprises second electronic control means for controlling, during said first time interval, an operation of said second light-emitting diode in light beam emission for lighting and / or signaling and, during said second time interval, an operation of said second light emitting diode in transmission of said detection light beam. Preferably, said second electronic control means comprise third switching means controlled during said second time interval for connecting said second light-emitting diode to a second power supply.

  Without limitation, the lighting device and / or signaling according to the invention may be in the form of a position light, a direction indicator, an interior lighting device, a projector or fog lamp , a stop light, a raised brake light, a reversing light, a rear lantern light, a repeater, an optical hubcap or a front headlamp.

  In another aspect, the present invention provides a detection system for a motor vehicle. According to the invention, the system comprises at least one optical beam detection function provided by at least one light-emitting diode included in a lighting device and / or signaling said motor vehicle, said light-emitting diode filling on the one hand, a light beam emission function required to provide illumination and / or signaling provided by said device and, on the other hand, said optical beam detection function.

  According to a particular embodiment, the system comprises at least two lighting and / or signaling devices as briefly described above and means for managing and controlling predetermined detection and perimetry functions, said management and control means controlling said at least two devices so as to perform each of said predetermined detection and perimetry functions with one or more electroluminescent diodes included in said at least two devices.

  The invention also relates to a motor vehicle comprising at least one lighting and / or signaling device as briefly described above.

  In a lighting and / or signaling device according to the invention, the light emission of a Led diode or a set of LED diodes may be continuous (in the case for example of a stop light), discontinuous ( in the case for example of a direction indicator) or pulse width modulated (PWM) or in pulse form, according to the command provided by the electronics. Thus, for example, in a device according to the invention comprising an obstacle detection function by taking into account a reflected light pulse, one or more LEDs can be driven in such a way as to emit a light pulse of maximum intensity for a short time, for example 1 ps, that is to say, for a period so short that this pulse remains imperceptible to the human eye. According to one embodiment of the invention, to receive the light pulse reflected by a nearby obstacle, there is provided in the device a detection chain which is connected at the input, for the adequate duration, to one or more LEDs Led which during this time are placed in receive mode to provide a measurement signal representative of the reflected light pulse.

  The detection applications, strictly speaking, can be implemented in the devices according to the invention comprising at least one Led diode. These applications include, for example, but not limited to: day / night detection and detection of the presence of public lighting lamps (100 Hz or 120 Hz), for example for a control of the lighting functions in urban mode (Town Lighting in English), automatic lighting / modulation of lighting functions or detection of functions actuated by other drivers in the periphery of the vehicle (for example, the operation of a direction indicator); - The detection of the luminous flux emitted or reflected by a previous vehicle for example for pre-collision or control of the alternator-starter function (function called Stop &Go); - The detection of the luminous flux of vehicles arriving in the opposite direction, for example for pre-collision purposes (for example, by detecting an abnormal increase in luminous flux with respect to speed); and detection of automatic recognition of direction indicators of other vehicles.

  Other applications requiring light beam transmitting / receiving functions such as obstacle detection can be implemented in the devices according to the invention comprising at least two LEDs. These applications concern, in a non-limiting manner, parking assistance and pre-collision, and in particular: The use of a two-LED (or more) LED position light as side proximity detector; The use of a two LED (or more) LED position light as a detector to measure the positioning and length of the slot during a slot; - The use of a repeater (or other peripheral LEDs, such as those possibly installed in side mirrors) as detector for parking assistance, for detecting the proximity of a pedestrian / cyclist, for folding automatic mirrors and others; - The use of the repeater to predispose the vehicle in a so-called wake up mode and turn on the door sills; - The use of direction indicators as side proximity detectors (blind spot) to map the front and / or rear of the vehicle; The use of direction indicators as assist sensors for side parking (in parallel with repeaters); and - The use of two (or more) Led diode interior lights as a non-contact proximity switch for automatic lighting of these interior lights.

  The present invention is also of interest for the following applications: The use of direction indicators for measuring the ignition and performance of all lamps and / or LEDs. In headlamps and taillights, the scattering of light is such that all light sources are detectable. The principle is therefore to control that the output signal of one of the diodes of the direction indicator in standby mode (or the daylight called DRL for Day Running Light in English) changes every time one turn on / off a lamp or other diode. Similarly, it is possible to detect the movement of a turn code (called DBL for Dynamic Bending Light in English) because of the light scattering in the projector, which makes it possible to delete a fault detection sensor which is usually present in DBL devices. Moreover, the permutation in the mode of detection of the LED diodes of the direction indicators and / or the DRL modules (in emission function) makes it possible to obtain a faithful image of the evolution of the output signal of the lamps and led diodes. and correlatively the aging thereof, this information can be made available on a bus (eg CAN / LIN) to which are connected the projectors / lights. In addition, the detection of the return signal by the LED or LEDs operating in optical sensor also allows in a projector to have information on a possible water deposit present on the projector glass, this information being then usable for a control of the projector washer.

  - The use of rear signaling LEDs (Anti-fog, stop light, rear lantern, direction indicator, raised brake light, reversing light and others) of the same function and / or combined in synchronism with devices different on each side, for a detection with triangulation of a rear obstacle, in pre-collision functions at the rear (by detection of an abnormal increase of the luminous flux with respect to the speed), of control of the so-called functions ARS (for Adaptive Rearlighting System) or parking assistance.

  The centralization of the control and the synchronized synchronization of pairs of LED lighting-function diodes located in different lighting and / or signaling devices, in particular in order to draw up a perimetric cartography of the environment of the vehicle, develop information redundancy strategies to make all information reliable in the event of a security function (pre-collision system, blind spot information system, etc.), to generate information and to driver assistance commands (parking assistance, in particular), making available on a bus information that may be used by other users.

  Other aspects and advantages of the present invention will appear more clearly on reading the description of particular embodiments which will follow, this description being given by way of nonlimiting example and with reference to the accompanying drawings, in which: which: Fig.1 is a partial front view of a signaling light according to the invention equipped with six light emitting diodes; Fig.2 is a partial vertical sectional view of the light of Fig.1, in an obstacle detection application; Fig.3 is a functional timing diagram showing first and second time intervals in the operation of the diodes dedicated respectively to the emission of signaling light beams and to the detection; and Fig.4 shows an electronic circuit diagram of the traffic light of Fig.1.

  Referring to Figs.1 to 4, there is now described a first particular embodiment, generally designated 1, a signaling device according to the invention being in the form of a rear lantern light.

  As shown in FIG. 1, in this particular embodiment of the invention, the light 1 comprises six LED diodes arranged in two horizontal rows of three diodes each, namely, D1, D2, D3 and D4, D5, D6. .

  The diodes D1 to D6 have similar characteristics and all participate in the signaling light function when the light 1 is activated in a so-called MS signaling mode.

  According to the present invention, the light 1 also operates in a so-called detection mode MD in which a part of the diodes, namely D1, D2 and D3, operate as light beam emission means and another part of the diodes , namely D4, D5 and D6, operate as light beam receiving means.

  With reference to Fig. 2, when the light 1 is operating in the MD detection mode, a FLE light beam is emitted by the diodes D1 to D3 (D1 only is shown in the schematic sectional view of Fig. 2) . The FLE beam is reflected by an obstacle 02 in the form of a reflected light detection beam FLR. The beam FLR is received by the diodes D4 to D6 and these output a measurement signal from which it is possible to determine the presence or absence of an obstacle.

  The operation of the light 1 in the MS signaling mode or in the MD detection mode is managed according to a principle of time division or time division multiplexing.

  As shown in FIG. 3, first time slots ITS are dedicated to the MS signaling mode and second ITD time slots are dedicated to the detection mode MD.

  In the MS signaling mode, during the ITS time intervals, the diodes D1 to D6 are in an illuminated state L or an off state D, depending on whether the signaling function is activated or not.

  In the MD detection mode, according to this particular embodiment of the invention, the ITD time slots typically have a duration of the order of 1 ps. This duration of 1 μs is sufficiently short that the ITD intervals remain imperceptible by the human eye and is compatible with the rise, fall and other times of commercially available LED diodes usable in the automobile.

  As it appears in FIG. 3, during the ITD intervals, the diodes D1 to D3 are activated in the illuminated state L and produce the beam FLE, while the diodes D4 to D6 operate as an optical sensor and detect the beam FLR. In response to the reception of the beam FLR, the diodes D4 to D6 deliver a measurement signal SM which is taken into account during a measurement period DM.

  With particular reference to FIG. 4, an electronic circuit included in the lamp 1 is now described in simplified form.

  As shown in Fig.4, the diodes D1 to D6 are mounted in a series-parallel configuration.

  The diodes D1, D2 and D3 are connected in parallel, having anodes connected at a point P1 and cathodes connected at a point P2.

  The diodes D4, D5 and D6 are also connected in parallel, having anodes connected to the point P2 and cathodes connected to a point P3.

  The point P1 of the circuit is connected through a resistor R3 to first terminals of first and second switches 11 and 12. Second terminals of the switches 11 and 12 respectively receive DC voltages Vcc and Vcc / 2.

  The DC voltage Vcc is applied between the point P3 and the second terminal of the switch I1. The DC voltage Vcc / 2 is applied between the point P2 and the second terminal of the switch 12.

  The circuit also comprises a control module 2 and a detection circuit 3.

  The control module 2 controls in particular the sequencing of the time intervals ITS and ITD through the openings / closures of the switches 11, 12 and a switch 13 included in the detection circuit 3.

  The switch 13 is connected in series between the point P2 and a first input of an amplifier 30, for example, a transimpedance amplifier. A second input of amplifier 30 is connected to point P3. The amplifier 30 outputs the measurement signal SM representative of the light beam FLR detected by the diodes D4 to D6.

  In addition to the switch 13 and the amplifier 30, the detection circuit 3 also comprises a filtering / demodulation module 31 and a threshold capacitor 32.

  The filtering / demodulating module 31 performs a filtering function which determines the frequency band of the signal SM which is taken into consideration. The module 31 can also provide a demodulation function, for example in an embodiment in which the transmitted signal is a signal with a carrier, and / or an additional detection function, for example when the quantity of interest is a peak value of the signal SM .

  The comparator 4 provides a decision function relative to the detection or not of an obstacle. For this purpose, the SM signal, designated SM1 after processing by the module 31, is compared with a detection threshold SD to provide an obstacle detection signal DO.

  When the light 1 is in signaling mode, during the time slots ITS, the switches 12 and 13 are open, thus ensuring a disconnection of the circuit with respect to the voltage Vcc / 2 and the circuit 3. The LEDs Led D1 to D6 are then fed from the voltage Vcc, according to the command opening / closing of the switch I1 to activate or not the light signaling.

  When the light 1 is in the detection mode, during the ITD time slots, the switch 11 is open, thus ensuring a disconnection of the circuit with respect to the voltage Vcc, and the switches 12 and 13 are closed. The switch 12 being closed, the diodes D1 A D3 are then fed from the voltage Vcc / 2, thus allowing the emission of a light beam FLE to a possible obstacle 02. The closing of the switch 13 connects the amplifier 30 at the terminals of diodes D4 to D6 which then operate as an optical sensor.

  Of course, the present invention is not limited to the details of the embodiments described here by way of example, but instead extends to the various modifications to the scope of the art that will be dictated by the applications contemplated of the invention.

  Thus, for example, a detection and / or perimetry function can be performed in a vehicle with the contribution of one or more LEDs included in one or more lighting devices and / or signaling according to the invention. Management and control means are then provided in the vehicle to control a coordinated operation of LEDs included in different devices. For example, in the case of an obstacle detection, an LED diode included in a first device will emit the detection light beam FLB and the beam FLR reflected by the obstacle will be detected by another LED diode included in a second device .

  The invention can therefore take a multitude of different embodiments of which only some examples are detailed in the present description. The scope of the invention is defined by the

appended claims.

Claims (9)

  1. Lighting and / or signaling device for a motor vehicle, incorporating a detection function and comprising at least a first light-emitting diode (D4, D5, D6) as a light source, characterized in that, in addition to a transmission function light beam required to provide illumination and / or signaling provided by the device, said first light-emitting diode also performs a function of optical detection of light beams.   2. Device according to claim 1, characterized in that it also comprises first electronic control means for controlling, during at least a first time interval (ITS), an operation of said first light emitting diode for transmitting light beams. illumination and / or signaling and, for at least a second time interval (ITD), an operation of said first light-emitting diode in optical detection of light beams; and electronic detection means connected to said first light emitting diode for receiving a measurement signal produced thereby in response to receiving a light beam during said second time interval and outputting a detection information (DO) derived from a processing of said measurement signal.   3. Device according to claim 2, characterized in that said electronic control means comprise first switching means (I1) controlled during said second time interval for disconnecting a first power supply (Vcc) of said first light-emitting diode; and second switching means (13) controlled during said second time interval for connecting said electronic sense means to said first light emitting diode.   4. Device according to claim 2 or 3, characterized in that said electronic detection means comprise amplification means and / or filtering means and / or demodulation means and / or threshold detection means.   5. Device according to any one of claims 1 to 4, characterized in that it also comprises at least a second light-emitting diode (D1, D2, D3) as a light source also filling, in addition to a beam emission function light required to provide illumination and / or signaling provided by the device, a function for emitting a detection light beam (FLE) of which at least one part (FLR) is capable of being reflected by an obstacle (02 ) and detected by a said first light-emitting diode (D4, D5, D6) fulfilling said optical beam detection function.   6. Device according to claim 5, characterized in that it also comprises second electronic control means for controlling, during said first time interval, an operation of said second light-emitting diode in light beam emission for lighting and / or signaling and, during said second time interval, an operation of said second light-emitting diode in transmission of said detection light beam.   7. Device according to claim 6, characterized in that said second electronic control means comprise third switching means (12) controlled during said second time interval for connecting said second light-emitting diode to a second power supply (Vcc / 2) .   8. Device according to any one of claims 1 to 7, characterized in that it is in the form of a position light, a direction indicator, an interior lighting device, a projector or fire fog, a brake light, a raised brake light, a reversing light, a rear lantern light, a repeater, an optical hubcap or a front headlamp.   9. Motor vehicle characterized in that it comprises at least one lighting device and / or signaling for a motor vehicle according to any one of claims 1 to 8.