Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
  • H05B45/30—Driver circuits
  • H05B45/37—Converter circuits
  • H05B45/3725—Switched mode power supply [SMPS]
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
  • H05B45/10—Controlling the intensity of the light
  • H05B45/14—Controlling the intensity of the light using electrical feedback from LEDs or from LED modules
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
  • H05B45/10—Controlling the intensity of the light
  • H05B45/18—Controlling the intensity of the light using temperature feedback
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
  • H05B45/40—Details of LED load circuits
  • H05B45/44—Details of LED load circuits with an active control inside an LED matrix
  • H05B45/48—Details of LED load circuits with an active control inside an LED matrix having LEDs organised in strings and incorporating parallel shunting devices

Definitions

• TITLE LIGHTING SYSTEM INCLUDING A PIXELIZED LIGHT SOURCE AND A
• the invention relates to the field of automotive lighting. More specifically, the invention relates to a motor vehicle lighting system incorporating a pixelated light source.
• lighting systems comprising sufficient selectively controllable elementary light sources, to allow the realization of pixelated light functions, for example containing at least 500 pixels, each pixel being formed by an elementary light beam emitted by one of the elementary light sources.
• This type of lighting system allows the motor vehicle to perform, for example, anti-glare road-type lighting functions, in which certain pixels of the high beam are extinguished or attenuated to form a dark zone at the level of a target object at do not dazzle, such as a followed or passed vehicle.
• monolithic pixelated light-emitting diodes comprising a plurality of elementary light emitters each forming one of the elementary light sources.
• Each of the elementary emitters is supplied by a controlled current source dedicated to this emitter and which makes it possible to activate or not the emission of a pixel.
• All of the controlled current sources are integrated into a single integrated circuit, for example placed under the elementary emitters. Due to the use of controlled current sources, this type of system has several drawbacks, namely: to introduce significant electrical power losses at the integrated circuit level, to increase the reaction time of the pixelated light-emitting diode and to increase the silicon surface required, and therefore the cost, of the integrated circuit.
• this type of lighting system forms an open loop system and, as such, is unstable and therefore unreliable.
• the characteristics of the monolithic pixelated light-emitting diode such as for example the threshold voltage of the elementary emitters, can vary, in particular as a function of the temperature.
• the electric power supplied by the power converter is not regulated, a loss of luminous flux at the output of the pixelated light source can be observed or else a thermal runaway.
• the pixelated light source may be distant from the power converter and therefore require a particularly long connection beam, which introduces impedance losses which therefore weaken the stability of the system.
• the invention relates to a lighting system for a motor vehicle, comprising: a. a pixelated light source having a plurality of selectively activatable elementary light sources, the activation of each elementary light source being exclusively controlled by a switch dedicated to this elementary light source; b. a power converter arranged to supply electric power to the pixelated light source; vs. a controller arranged to control the electric voltage supplied by the power converter and to control the switches controlling the activation of the elementary light sources.
• the invention is characterized in that the lighting system comprises an electric current sensor arranged to measure the electric current supplied by the power converter to the pixelated light source and to transmit information relating to this measured current to the controller.
• the controller has information relating to the intensity of the electric current supplied by the power converter to the pixelated light source. Therefore, this information can be used by the controller to regulate the electrical power at the output of the converter, whether it is to stabilize this electrical power with respect to the need for the pixelated light source, including in the event of strong variations in temperature. the ambient temperature at the level of this light source, or whether this is to compensate for impedance losses at the level of a connection beam between the power converter and the light source.
• pixelated light source any light source comprising a plurality of elementary light sources, each optionally being associated with an electro-optical element and being capable of being activated and selectively controlled to emit a beam.
• elementary luminous whose luminous intensity is controllable.
• the pixelated light source may comprise a monolithic pixelated light emitting diode comprising a plurality of elementary light emitters, each of the elementary emitters of the monolithic pixelated light emitting diode forming one of the elementary light sources.
• the plurality of elementary light emitters can be stacked on an integrated circuit in which said switches are integrated.
• the elementary light sources can be arranged so that each elementary light beam forms a pixel and so that all the pixels form a pixelated light beam, for example comprising 500 pixels of dimensions between 0.05 ° and 0.3 °, distributed over a plurality of rows and columns, for example 20 rows and 25 columns.
• the lighting system does not have a controlled current source associated with each of the elementary light sources.
• the electric current sensor is connected between the power converter and the pixelated light source.
• the electric current sensor comprises a Hall effect sensor.
• the current sensor comprises a magnetoresistor, for example a tunnel effect magnetoresistance (also called TMR sensor, standing for Tunnel MagnetoResistor).
• TMR sensor tunnel effect magnetoresistance
• TMR sensor standing for Tunnel MagnetoResistor
• the controller is arranged to modify the value of the electric voltage supplied by the power converter as a function of said information relating to the measured current transmitted by the electric current sensor. For example, if the measured electric current has an intensity lower than a predetermined threshold value, the controller can be arranged to request an increase in the voltage supplied at the output of the power converter, for example to guarantee a luminous flux emitted by the light source pixelated that is of constant intensity. In another example, if the measured electric current has an intensity greater than a predetermined threshold value, the controller can be arranged to request a decrease in the voltage supplied at the output of the power converter, for example to prevent thermal runaway of the source. pixelated light.
• the lighting system may include a temperature sensor arranged to measure the ambient temperature in the vicinity of the pixelated light source and a memory in which are stored the emission characteristics of the pixelated light source, in particular the threshold voltages of each of the elementary light sources.
• the controller is arranged to modify the value of the electric voltage supplied by the power converter as a function of said information relating to the measured current transmitted by the electric current sensor, the ambient temperature measured by the temperature sensor and the emission characteristics of the pixelated light source stored in the memory.
• the controller is arranged to receive an instruction to transmit a pixelated light beam desired by the pixelated light source and to determine a necessary electrical power setpoint to be supplied by the power converter to the light source pixelated for emitting said desired pixelated light beam.
• the controller can be arranged to modify the value of the electric voltage supplied by the power converter as a function of said information relating to the measured current transmitted by the electric current sensor so that the electric power supplied by the power converter is substantially identical to the determined necessary electrical power setpoint.
• the controller can be arranged to receive an instruction to transmit a desired pixelated light beam in the form of a digital image representing a projection of said desired pixelated light beam, each point of the digital image representing in particular the luminous intensity of the pixelated light beam in a point in space.
• the controller is arranged to determine an electrical power setpoint necessary to be supplied by the power converter to the pixelated light source so that the light intensity of the pixelated light beam, and in particular of each of the pixels, matches that of the digital image.
• the controller can be arranged to control the pixelated light source so that each light source emits a pixel corresponding to one or more points of the digital image.
• the controller and the power converter are arranged on a first printed circuit board, and the pixelated light source and the electric current sensor are arranged on a second printed circuit board .
• the first printed circuit board and the second printed circuit board are connected to each other by a connection harness.
• the controller is arranged to determine, from the information relating to the measured current transmitted by the electric current sensor, a loss of impedance in the connection harness.
• the controller is designed to modify the value of the electric voltage supplied by the power converter so as to compensate for said loss of impedance in the connection harness determined by the controller.
• FIG. 1 shows a lighting system according to one embodiment of the invention.
• FIG. 1 a lighting system 1 of a motor vehicle according to one embodiment of the invention.
• This lighting system 1 comprises a pixelated light source 2 capable of emitting a pixelated light beam.
• the pixelated light source 2 is a monolithic pixelated light-emitting diode comprising a plurality of elementary light emitters 21 stacked on an integrated circuit in which a plurality of switches 22 are integrated, each switch 22 controlling the activation. or the deactivation of one of the elementary light emitters 21 to which it is thus dedicated.
• Each of the light emitting elements 21 forms an elementary light source which can be activated and controlled selectively and exclusively by means of the switches 22 to emit an elementary light beam the light intensity of which is controllable and thus forming a pixel of the pixelated light beam.
• the lighting system 1, and in particular the light source 2 does not have a controlled current source associated with each of the elementary light emitters 21.
• the pixelated light source 2 can be part of a light module of the lighting system and thus be associated with an optical element making it possible to shape the elementary light beams.
• the light source 2 comprises 500 elementary light emitters 21 distributed in a matrix over a plurality of rows and columns, for example 20 rows and 25 columns, each emitter being able to emit, for example in association with an optical device. not shown, a pixel of dimensions included in 0.05 ° and 0.2 °.
• the lighting system 2 can also include other light sources or modules, pixelated or not.
• the lighting system 1 comprises a power converter 3, for example of the DC / DC type, arranged to provide, from an electrical power Pe received from an energy source of the motor vehicle such as a battery, an electric power Ps to the pixelated light source 2.
• the lighting system 1 comprises in in addition to a controller 4 arranged to control on the one hand the pixelated light source 2, and more specifically each of the switches 22, and on the other hand the power converter 3. More precisely, the controller 4 is arranged to control and / or modify the value of the electric voltage Vs supplied by the power converter 3.
• the lighting system 1 comprises an electric current sensor 5 arranged to measure the electric current Is supplied by the converter 3 to the pixelated light source 2 and to transmit information relating to this measured current Is to the controller 4.
• This electric current sensor 5 comprises a Hall effect sensor mounted between the power converter 3 and the pixelated light source 2.
• the controller 4 and the power converter 3 are arranged on a first printed circuit board, and the pixelated light source 2 and the electric current sensor 5 are arranged on a second printed circuit board , the first printed circuit board and the second printed circuit board being connected to each other by a connection harness 6, through which passes the electric power Ps supplied by the converter 3.
• the controller 4 is arranged to receive an emission instruction Im of a pixelated light beam desired by the pixelated light source 2, in the form of a digital image representing a projection of said light beam pixelated desired, each point of the digital image representing in particular the light intensity of the pixelated light beam in a point in space.
• the controller 4 thus determines an electrical power setpoint necessary to be supplied by the power converter B to the pixelated light source 2 for the emission of said desired pixelated light beam, for example so that the light intensity of the light beam pixelated, and in particular of each of the pixels, corresponds to that of the digital image Im.
• the controller 4 transmits an activation instruction based on the digital image Im to the switches 22 of the pixelated light source 2 in order to control the activation or deactivation of each of the elementary light emitters 21, so that the all the pixels emitted by these elementary emitters 21 form a pixelated light beam corresponding to the digital image Im.
• the controller 4 is arranged to modify the value of the electric voltage Vs supplied by the power converter 3 as a function of said information relating to the measured current Is transmitted by the electric current sensor 5, in particular so as to regulate the power electrical power Ps supplied by the converter 3 in accordance with the power setpoint determined by the controller 4.
• the controller 4 if the measured electric current Is has an intensity lower than a predetermined threshold value, the controller 4 requires an increase in the voltage Vs supplied at the output of the power converter 3, so as to guarantee a luminous flux emitted by the pixelated light source 2 which is of constant intensity.
• the controller 4 requires a decrease in the voltage Vs supplied at the output of the power converter 3, for example to prevent thermal runaway of the source. pixelated light 2.
• the controller 4 can determine, from the information relating to the measured current Is, a loss of impedance in the connection harness 6 and can thus modify the value of the electric voltage Vs supplied by the converter of power 3 so as to compensate for this loss of impedance in the connection harness 6.
• the invention cannot be limited to the embodiments specifically described in this document, and extends in particular to all equivalent means and to any technically operative combination of these means.
• it is possible to provide other modes of exploitation of the information relating to the measured current transmitted by the current sensor for example by integrating at the level of the controller a memory containing a map of the characteristics of the pixelated light source as well as 'a temperature sensor in the vicinity of the pixelated light source.

Landscapes

• Lighting Device Outwards From Vehicle And Optical Signal (AREA)
• Circuit Arrangement For Electric Light Sources In General (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=69158099

Family Applications (1)

Country Status (7)

Family Cites Families (22)

• 2019
  • 2019-10-15 FR FR1911433A patent/FR3101931B1/fr active Active
• 2020
  • 2020-10-14 WO PCT/EP2020/078974 patent/WO2021074259A1/fr unknown
  • 2020-10-14 US US17/765,049 patent/US11877366B2/en active Active
  • 2020-10-14 JP JP2022522728A patent/JP7402324B2/ja active Active
  • 2020-10-14 KR KR1020227012421A patent/KR20220062387A/ko not_active Application Discontinuation
  • 2020-10-14 CN CN202080072329.2A patent/CN114586472A/zh active Pending
  • 2020-10-14 EP EP20788834.8A patent/EP4046465A1/de active Pending

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