Lighting system comprising a light module capable of emitting a pixelated light beam

Abstract

The invention relates to a method for controlling a light source comprising a plurality of light elements, a predefined set of light elements of the matrix light source being capable of projecting a light beam onto a regulatory point associated with a minimum intensity threshold. If a command for activating or deactivating a light function verifies (701) activation conditions of the predefined set, the method comprises activating (703) groups of light elements included in the predefined set of light elements, so as to project a light beam onto the regulatory point at a light intensity greater than the minimum light intensity threshold. Each group of light elements comprises adjacent light elements in the predefined set, and in which the groups are separated by deactivated light elements. FIG. 7

Description

Title of the invention: Lighting system comprising a light module capable of emitting a pixelated light beam

[0001] The present invention relates to the field of automotive lighting. More specifically, the invention relates to a motor vehicle lighting system provided with a light module capable of emitting a pixelated light beam.

[0002] Most states, countries or regions define regulations that a motor vehicle must comply with in order to be able to circulate. In particular, there are regulations requiring that the lighting emitted by a front headlight of a motor vehicle meets certain constraints, under certain conditions. This is particularly the case for low beam lighting, also called LB, for “Low Beam” in English, which, in most regulations, must be achieved by a low beam having a higher cut-off, delimiting an illuminated area from an area not illuminated by this lighting, and having, at certain points, a luminous intensity greater than a given minimum threshold and at other points, a luminous intensity lower than a given maximum threshold.

[0003] In order to assess the compliance of a projector with a regulation, the light beams emitted by this projector are projected onto a screen provided with an orthonormal reference mark and a photometric grid consisting of regulatory points placed on this screen and defining maximum or minimum thresholds of luminous intensity. The respective values ​​of luminous intensity of the beams at the regulatory points associated with maximum and minimum thresholds make it possible to verify whether the light beam complies with the regulation. When several beams are superimposed at the same point, it is the sum of the luminous intensities of the beams at this point which must respect the minimum or maximum threshold.

[0004] Some of these regulatory points associated with maximum thresholds are positioned above the horizontal axis of the reference mark, in order to ensure that the dipped beam does not dazzle drivers of other vehicles on the road. Such regulatory points are called glare points.

[0005] These regulations may also define, for other regulatory points located above the cut-off, minimum light intensity values. This is particularly the case for points called gantry points, which correspond to locations of traffic signs which must be illuminated.

[0006] However, these gantry points pose several problems. Their respective locations are close to the glare points located above the cutoff. It is therefore necessary to be able to delimit, in the light beam, associated zones at the gantry points, whose light intensities are higher than the minimum thresholds associated with the gantry points, and areas associated with glare points, whose light intensities are lower than the maximum thresholds of these glare points, the gantry point areas and the glare point areas possibly being close.

[0007] The headlights are also capable of projecting a high beam, in addition to the dipped beam, and activatable on command, also called HB, for “High Beam” in English, and the majority of which is located above the cut-off of the dipped beam. The high beam allows powerful illumination of the vehicle's surroundings, above the dipped beam. When the high beam is activated, the thresholds associated respectively with the gantry points and the glare points do not have to be respected: these regulatory points only apply when the high beam is deactivated.

[0008] It is now possible to produce a high beam by creating tunnels in the high beam, thanks to an adaptive lighting function, called ADB, for “Adaptive Drive Beam”, based on the detection of positions of other vehicles facing the vehicle in which the lighting system is integrated. The high beam is thus segmented, and it is possible to turn off a segment, thus forming a tunnel in which other vehicles traveling on the road are not dazzled.

[0009] Specific regulations may apply to such tunnels. For example, regulations may impose a maximum threshold of light intensity in the entire tunnel, or in specific regulatory points of the tunnel, when the main beam is activated. Such a maximum threshold also applies to the sum of the light intensities from the lighting beams (main beam and dipped beam), but also to the signaling beams (position beam, or PL, for “Position Lighting” in English).

[0010] However, in certain regulations, in the United States in particular, if a gantry point is located in a high beam tunnel, both the regulations specific to the tunnel (maximum threshold of light intensity in regulatory points of the tunnel) and those linked to the gantry points must be respected so that the lighting beams are compliant. Such a situation is even more restrictive than the aforementioned situation of proximity of the gantry points and the glare points when the high beam is deactivated.

[0011] As a result, great precision in the spatial delimitation of the zones in the lighting beams, but also in the definition of the value of the light intensity in these zones, is required to obtain light beams that comply with all regulations.

[0012] In order to address these problems, it is known to use a lighting module, complementary to a lighting module LB projecting the dipped beam and a lighting module HB projecting the main beam ADB, comprising a light source with selectively activatable light elements, to allow the production of a pixelated beam in addition to the ADB beam and the dipped beam. Such a source is called a matrix source and each light element of the matrix source can form an elementary light beam forming a pixel of the pixelated beam.

[0013] Beyond the fact that this type of light module allows advanced lighting functions to be performed, for example anti-glare, floor writing or reception scenarios, it also allows the light intensity to be controlled in precisely delimited areas. It is thus theoretically possible to delimit an emission zone comprising a gantry point and an emission zone comprising a glare point, or to delimit an emission zone comprising a gantry point precisely in an ADB tunnel.

[0014] However, in practice, inaccuracies during the assembly of the light modules as well as due to adjustment tolerances, require margins to be provided in the emission zone including the gantry point, which amounts to enlarging the emission zone illuminating the gantry point and delimited in the beam. However, the enlargement of the delimited emission zone can lead to a significant increase in the light intensity, due to a greater number of light elements dedicated to the emission zone, and the fact that the light intensities of the light elements overlap in practice. The light intensity can thus be high, including outside the gantry points, which can cause incompatibility with the regulations relating to glare points, when the main beam function is deactivated, or with the regulations applied to ADB tunnels in segmented main beams.

[0015] There is thus a need to ensure sufficient illumination for a regulatory point, in particular a gantry point above the cut-off of a dipped beam, while avoiding dazzling other points in the vicinity of the regulatory point, in particular when the gantry point is in a tunnel of a segmented main beam ADB.

[0016] The present invention improves the situation.

[0017] A first aspect of the invention relates to a method for controlling a matrix light source of a lighting module, the matrix light source comprising a plurality of individually controllable light elements, in which a predefined set of light elements of the matrix light source is capable of projecting a light beam into an emission zone comprising a regulatory point associated with a minimum threshold of light intensity, the method including: - upon receipt of a command to activate or deactivate at least one lighting function, verification that the command satisfies at least one condition for activating lighting elements of the predefined set; - if the command satisfies each activation condition among said at least one activation condition, activation of groups of light elements included in the predefined set of light elements, so as to project a light beam onto the regulatory point at a light intensity greater than the minimum light intensity thresholds.

[0018] Each group of light elements comprises adjacent light elements in the predefined set, and the groups are separated by deactivated light elements.

[0019] Thus, it is made possible to illuminate the emission zone comprising the regulatory point with a predefined set of light elements of a matrix light source, which makes it possible to control the shape of the light beam with a precision dependent on the resolution of the source. Activating separate groups of light elements not only makes it possible to control the precision associated with the light intensity projected onto the regulatory point, while also controlling the spatial dimension of the beam emitted by the predefined set. Homogeneity is ensured within the beam emitted by the predefined set due to a blur intrinsic to each light element of the source. A margin is further ensured, which makes it possible to ensure compliance with the regulatory point without requiring excessive precision when installing the lighting module in a motor vehicle headlight.

[0020] According to embodiments, the regulatory point may be a gantry point, and, when the predefined assembly projects the light beam onto a screen, the regulatory point may be included in a pixel of the projected beam lying vertically between 1° and 3°, in particular between 1.5° and 2.5°.

[0021] The invention is particularly advantageous in the context of illuminating a gantry point, insofar as this regulatory point is located above a cut-off of a dipped beam, and therefore requires significant precision in order not to dazzle other road users.

[0022] Additionally, the lighting module comprising the matrix light source may be a first lighting module of a lighting system further comprising a second lighting module capable of projecting an adaptive segmented high beam, and the at least one activation condition may comprise the following activation conditions: - the command is an adaptive segmented high beam activation command, indicating a deactivation of at least one segment of the high beam segmented; - the at least one deactivated segment of the segmented high beam defines a tunnel of absence of light emission including the regulatory point.

[0023] The invention is particularly advantageous for illuminating a gantry point located in a tunnel of a segmented road beam of the ADB type, in particular in order to meet regulatory constraints in certain countries. Indeed, in an ADB tunnel, the regulatory gantry point associated with the minimum threshold of light intensity may be close to another regulatory point associated with a maximum threshold of light intensity, and precise control of the light beam illuminating the gantry point as well as its light intensity is thus required.

[0024] According to embodiments, the set of light elements can be predefined so that, when the light beam of the predefined set is projected onto a screen, the emission zone can extend horizontally between a first horizontal position and a second horizontal position, a first difference between the first horizontal position and the regulatory point being less than 1° and / or a second difference between the second horizontal position and the regulatory point being less than 1°.

[0025] Thus, the emission zone is both of restricted size so as to make the illumination of the regulatory point compatible with other nearby regulatory points, but of sufficient size so as not to require excessively restrictive precision during the installation and calibration of the light module in a vehicle headlight.

[0026] According to embodiments, the light elements of the matrix light source may be arranged in rows and columns, and each group of light elements may comprise M light elements, M being an integer less than or equal to 50, in particular less than 20, and preferably less than 15.

[0027] By composing several small groups, separated by extinguished light elements, it is possible to take advantage of the blur intrinsic to each light element to compose a homogeneous light beam illuminating the regulatory point.

[0028] According to a first embodiment, the light elements of the matrix light source may be arranged in rows and columns, and each group of light elements may comprise N rows of light elements from the predefined set, N being between 1 and 3, two groups one above the other being separated by at least one row of deactivated light elements and by at most four rows of deactivated light elements.

[0029] The first embodiment provides an acceptable visual rendering, with blurred horizontal bands that are of little disturbance to the driver of the vehicle.

[0030] According to a second embodiment, the groups of activated light elements can be arranged in a checkerboard pattern within the predefined set, and each group can include fewer than 10 light elements, including fewer than 5 light elements.

[0031] The second embodiment makes it possible to precisely define the light intensity in the emission zone comprising the regulatory point.

[0032] According to a third embodiment, the light elements of the matrix light source can be arranged in rows and columns, and each group of light elements can comprise N diagonals of light elements from the predefined set, N being between 1 and 3, two consecutive groups being separated by at least two diagonals of deactivated light elements and by at most three diagonals of deactivated light elements.

[0033] The third embodiment also allows a visual rendering acceptable to the driver of the vehicle in which the lighting module is integrated.

[0034] According to embodiments, the light elements of the matrix light source may be of submillimeter dimensions and are epitaxially grown directly on a common substrate.

[0035] Such a so-called monolithic matrix source can comprise a very large number of light elements thus ensuring high resolution, which makes it possible to improve the precision associated with the illumination of the emission zone comprising the regulatory point.

[0036] A second aspect of the invention relates to a computer program comprising instructions for implementing the method according to the first aspect of the invention, when these instructions are executed by a processor.

[0037] A third aspect of the invention relates to a control module for a lighting module comprising a matrix light source comprising a plurality of individually controllable light elements, the control module comprising a memory storing positions of a predefined set of light elements of the matrix light source capable of projecting a light beam in an emission zone comprising a regulatory point associated with a minimum light intensity threshold, the control module comprising a processor configured to: - upon receipt, via a first interface, of a command to activate or deactivate at least one lighting function, verify that the command satisfies at least one condition for activating lighting elements of the predefined set; - if the command satisfies each activation condition among said at least one activation condition, transmitting a control signal to the lighting module to command an activation of groups of light elements included in the predefined set of light elements, so as to project a light beam onto the regulatory point at a light intensity greater than the minimum intensity threshold bright. Each group of light elements comprises adjacent light elements in the predefined set, and in which the groups are separated by deactivated light elements

[0038] A fourth aspect of the invention relates to a lighting system for a motor vehicle, comprising a control module according to the third aspect of the invention and a lighting module comprising a matrix light source comprising a plurality of individually controllable light elements.

[0039] According to embodiments, the lighting system may further comprise at least one other lighting module, capable of projecting a dipped beam of light to perform a dipped beam function and / or capable of projecting a main beam of light to perform a main beam function.

[0040] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings in which:

[0041] [Fig-1] illustrates a lighting system of a motor vehicle according to modes of realization of the invention;

[0042] [Fig.2] illustrates light beams produced by a lighting system according to embodiments of the invention;

[0043] [Fig.3] illustrates a part of the light beams produced by a lighting system according to embodiments of the invention;

[0044] [Fig.4] is a matrix light source according to embodiments of the invention;

[0045] [Fig.5a] is a predefined set of light elements of a matrix light source of a lighting module, in a configuration according to a first example;

[0046] [Fig.5b] is a predefined set of light elements of a matrix light source of a lighting module, in a configuration according to a second example;

[0047] [Fig.6a] is a predefined set of light elements of a matrix light source of a lighting module, according to a first embodiment of the invention;

[0048] [Fig.6b] is a predefined set of light elements of a matrix light source of a lighting module, according to a second embodiment of the invention;

[0049] [Fig.6c] is a predefined set of light elements of a matrix light source of a lighting module, according to a third embodiment of the invention; [Fig.7] is a diagram illustrating the steps of a method of controlling a matrix light source of a lighting module, according to embodiments of the invention;

[0050] [Fig.8] illustrates the structure of a control module of a lighting module comprising a matrix light source, according to embodiments of the invention.

[0051] The description focuses on the features that distinguish the lighting device from those known in the state of the art.

[0052] [Fig.l] shows a lighting system 100 for a motor vehicle according to embodiments of the invention.

[0053] The lighting system comprises two front projectors 110, one being arranged in a right part of the vehicle and the other being arranged in a left part of the vehicle, capable of projecting one or more beams in front of the vehicle in order to perform one or more lighting functions, described below.

[0054] A single projector 110 is shown, for the sake of simplification, in [Fig.l].

[0055] The projector 110 comprises at least two lighting modules according to the invention: a first lighting module 120 capable of projecting a pixelated beam 140 and a second lighting module 130 capable of projecting a dipped beam 160 and a high beam 150.

[0056] The second lighting module 130 is capable of performing the following lighting functions: - a low beam function, also called LB for “Low Beam” in English; and / or - a high beam function, also called HB for “High Beam” in English. The high beam function according to the invention is an adaptive segmented function, or ADB, for “Adaptive Drive Beam” in English, and presented below.

[0057] As a variant to that shown in [Fig.l], separate lighting modules can be provided for the LB function and for the HB function: the second module 130 is then dedicated to the LB function only, and a third module, not shown, is capable of performing the HB function.

[0058] The lighting system 100 comprises a central control module 101 of the vehicle, also called “body controller” in English, capable of receiving data from different sensor systems of the vehicle, such as the speed of the vehicle, the presence of other vehicles in the environment of the vehicle, associated with the positions of the other vehicles in space, relative to the vehicle, the presence of pedestrians, traffic signs. The central control module 101 can further receive map data indicating a road system in connection with a current position of the motor vehicle and road infrastructure elements. The central control module 101 can further receive instructions from the driver of the vehicle, such as instructions for activating or deactivating the high beam for example, or a command for activating or deactivating the dipped beam.

[0059] The central control module 101 is thus able to transmit commands for activating or deactivating a given lighting function, which may include parameters of the lighting function when the lighting function is to be activated. The parameters may in particular indicate a position of another vehicle for controlling the ADB function, for example. The commands for activating or deactivating the lighting function are transmitted to a control module 111.

[0060] The projector 110 in fact comprises the control module 111, also called “driver”, capable of determining control signals for the lighting modules 120 and 130, the control signals making it possible to carry out the lighting function (and its parameters) controlled by the central control module 101.

[0061] A first control signal may be transmitted to the first module 120 and a second control signal may be transmitted to the second module 130.

[0062] The second control signal can: - activate or deactivate the crossover function performed by the second module 130; - activating or deactivating the HB function, in particular activating or deactivating the ADB function by selectively activating certain segments of the high beam 150, as described below.

[0063] The first control signal is a digital image producing a portion of the controlled light function(s), in a frame whose dimensions and resolution correspond to those of an emission zone of the pixelated beam 140, represented in [Fig. 2] described below, in addition to the dipped beam 160 and / or the main beam 150 produced by the second lighting module 130.

[0064] The second lighting module 130 comprises a first control unit 131.1 capable of controlling a first light source 132.1 for producing the high beam 150 and a second control unit 131.2 capable of controlling a second light source 132.2 for producing the dipped beam 160. The first control unit 131.1 can activate or deactivate the first light source 132.1 as a function of the second instruction received, and preferably selectively control light elements of the first light source 132.1 to control the activation or deactivation of each segment of the segmented high beam 150. The second control unit 131.2 can activate or deactivate the second light source 132.2 as a function of the second instruction received from the control module 111.

[0065] The second lighting module 130 further comprises a projection optic 133 capable of projecting the light beams emitted from the first and second light sources 132.1 and 132.2 to produce the dipped beam 160 and the beam of road 150. No restriction is attached to the projection optics 133 which may comprise any combination of optical elements such as mirrors and / or optical lenses. The optical elements dedicated to the formation of the road beam 150 and the optical elements dedicated to the formation of the dipped beam 160 may be distinct.

[0066] The first lighting module 120 comprises a control unit 121 capable of controlling a matrix light source 122 comprising a plurality of light elements, for example electroluminescent. Each light element of the matrix source 122 is individually controllable by the control unit 121, that is to say that the control unit can activate or deactivate a light element independently of the control of the other light elements of the matrix source 122.

[0067] According to the invention, the matrix light source 122 may be of the monolithic type. A so-called "monolithic" source may have a particularly high density of light elements, which makes it particularly interesting for a plurality of applications. A monolithic source involves a plurality of electroluminescent semiconductor elements of submillimeter dimensions, epitaxially grown directly on a common substrate, the substrate generally being formed of silicon. Unlike sources comprising conventional LED matrices, in which each elementary light element is an electronic component produced individually and mounted on a substrate such as a printed circuit, PCB, a monolithic source is to be considered as a single electronic component, during the production of which several pads of electroluminescent semiconductor junctions are generated on a common substrate, in the form of a matrix.This production technique allows for the production of electroluminescent areas, each acting as an elementary luminous element, very close to each other. The gaps between the luminous elements can have submillimeter dimensions. An advantage of this production technique is the high level of pixel density that can result on a single substrate.

[0068] The individual light elements can be individually controlled by the control unit 121 capable of receiving from the control module 111 the first control signal in the form of a digital image. The individual control can comprise the control of the electrical power supplied to the individual light element, by pulse width modulation, or PWM, for “Pulse Width Modulation” in English. The control unit 121 can for example be an integrated circuit of the ASIC type, for “Application Specific Integrated Circuit” in English, which has the advantage of great compactness, and which can be integrated into the monolithic light source.

[0069] The digital image forming the first control signal can thus indicate, for each light element of the matrix source 122, a light intensity value to be achieved by the light element, from which the control unit 121 can determine a duty cycle value to be applied for controlling the PWM power supply of the light element. Alternatively, the digital image directly indicates a duty cycle value to be applied for each light element of the matrix source 122, for execution by the control unit 121.

[0070] The first lighting module 120 further comprises a projection optic 123 capable of producing the pixelated beam 140 from the light beam emitted by the matrix light source 122. No restriction is attached to the projection optic 123 which can comprise any combination of optical elements such as mirrors and / or optical lenses.

[0071] [Fig. 2] shows respective projections of the pixelated beam 140, the high beam 150 and the dipped beam 160, on a screen provided with an orthonormal reference frame and positioned 25 meters from the projector 110. In this reference frame, the coordinates correspond to horizontal and vertical angles measured from the origin of the reference frame. The positive abscissas correspond to the half-plane located to the right of the vertical axis VV, the negative abscissas correspond to the half-plane located to the left of the vertical axis VV, the positive ordinates correspond to the half-plane located above the horizontal axis HH and the negative ordinates correspond to the half-plane located below the horizontal axis HH.

[0072] No restriction is attached to the shape of the projections of the light beams 140, 150 and 160, [Fig.2] being given for illustrative purposes.

[0073] As explained above, the first light source 132.1 may be controlled so as to selectively activate or deactivate segments 151.1 to 151.8 of the high beam 150. For example, when another vehicle is detected at a position corresponding to one of the segments 151.1 to 151.8, the segment may be deactivated so as to maintain the high beam HB function without dazzling the driver of the other vehicle. The segment to be deactivated may be determined by the control module 111, which may indicate the segment to be deactivated to the first control unit 131.1 in the second control signal transmitted to the second lighting module 130. The deactivated segment thus forms a tunnel between two activated segments of the high beam 150.

[0074] As shown in [Fig.2], the pixelated beam 140 is capable of contributing to both the LB function, in particular to perform a cut-off along the HH axis in addition to the dipped beam 160, in a well-known manner. In addition, the pixelated beam partially overlaps with the main beam 150 and can thus contribute to the HB function, in particular to the ADB function.

[0075] No restriction is attached to the respective positions of the beams 140, 150 and 160. For example, the pixelated beam 140 can spread in width (left-right direction) between an angle of -25° and an angle of +25°, for example between an angle of -15° and an angle of 9°, the origin being fixed by the VV axis. Thus, the pixelated beam 140 can be offset in the left half-space of the reference frame, as shown in [Fig. 2]. The high beam 150 is shown as strictly above the line HH, for reasons of readability of the figure only. The pixelated beam 140 can spread in height (left-right direction) between an angle of -2° and an angle of +4° relative to the HH axis.The resolution of the projection of the pixelated beam 140 depends on the number of light elements of the matrix source 122, each light element producing an elementary emission zone of the projection of the pixelated beam 140, the elementary emission zone also being called a pixel of the pixelated beam 140.

[0076] According to the invention, the pixelated beam 140 can in particular be controlled to produce regulatory points of a photometric grid, as a function of the light function(s) controlled by the central control module 101.

[0077] As indicated previously, in order to assess the compliance of a projector with a regulation, the light beam projected onto a screen is compared with a photometric grid made up of points placed on this screen and defining maximum and / or minimum thresholds of light intensity.

[0078] [Fig.2] identifies a zone 200 comprising a regulatory photometric grid point, in particular one of the gantry points located above the horizontal axis HH, the zone 200 corresponding both to a part of the emission zone of the high beam 150 and to a part of the emission zone of the pixelated beam 140.

[0079] Note that in addition to allowing the control of the light intensity projected in emission zones comprising regulatory points, the pixelated beam can be controlled to perform other functions: - form a complementary upper cut-off of the dipped beam 160; - form a tunnel corresponding to a deactivated segment in the road beam 150; - display a pictogram and / or a ground marking, in the part of the pixelated beam 140 located under the horizontal axis HH; - add light intensity in certain areas, in addition to the 150 high beam or the 160 low beam.

[0080] [Fig.3] illustrates a portion of the illumination beams 140 and 150 with centering and zooming on the zone 200 of [Fig.2] comprising an emission zone with a regulatory photometric grid point, according to the invention.

[0081] The portion of the illumination beams 140 and 150 projected onto a screen such as re shown in [Fig.3] includes an emission zone 302, including a regulatory point.

[0082] The regulatory point included in the emission zone 302 can be located horizontally between -5° and -3°, for example equal to -4° horizontally, and vertically at a position between +1° and +3°, for example equal to +2° vertically. In this case, the regulatory point is the gantry point defined in the American regulation FMVSS 108 and usually referenced under the name 2U-4L. A minimum threshold is associated with this regulatory point and has a value of 135 candelas.

[0083] The emission zone 302 can thus extend on either side of the regulatory point with a vertical spread (thickness) of less than 1°, in particular less than 0.5°, and a horizontal spread (width) of less than 4°, in particular less than 3°. Such an emission zone tightened around the regulatory point makes it possible to comply with the regulatory constraint set by the regulatory point, in a precise manner, while making it possible to address other regulatory constraints close to the regulatory point. This is particularly the case in the example of the gantry point 2U-4L shown in [Fig. 3], which can be located in an ADB tunnel 301 of the road beam 150, the tunnel being formed by the deactivation of a segment 151.4, between two activated segments 151.3 and 151.5, in order in particular to avoid dazzling another driver located at a localized position in the tunnel 301.

[0084] According to American regulations, a maximum threshold of light intensity is imposed in each ADB tunnel, such as tunnel 301, for example for a point in a regulatory zone 303 which may be close to the emission zone 302, previously described. In the regulatory zone 303, the light intensity must be lower than the upper threshold of light intensity: however, the maximum threshold associated with the regulatory zone 303 may be close to or even lower than the minimum threshold associated with the point included in the emission zone 302, which requires great precision on the light intensity projected in the emission zone 302, so that it does not overflow into the regulatory zone 303.

[0085] In the case of [Fig. 3], the horizontal spread of the emission zone 302 to the left of the gantry point can advantageously be limited to 1°, or be less than 1°, in order to maintain a margin with respect to the regulatory zone 303. Note that in the context of a high-definition monolithic light source, which can form several tens of thousands of pixels, an emission zone with a horizontal spread of 1° has a width of the order of ten pixels. However, more generally, the number of pixels achieving a horizontal spread of 1° depends on the resolution of the matrix source as well as the projection optics.

[0086] In other examples, however, it is preferable to limit the horizontal spread to the right of the gantry point to 1°, or even less than 1°.

[0087] [Fig.4] shows the matrix light source 122 according to embodiments of the invention.

[0088] As indicated previously, the matrix light source 122 comprises a plurality of individually controllable light elements 401, the control being able to be carried out by a PWM power supply in particular, by the control unit 121 described previously. The light elements 401 can be distributed in a matrix, with a given number of columns and a given number of rows. In the example of [Fig. 4], to improve the readability of the figure, the matrix light source 122 comprises 12 rows and 18 columns. However, in practice, the matrix light source 122, in particular when it is of the monolithic type, can comprise several thousand light elements 401, or even several tens of thousands of light elements 401, distributed over several hundred rows and / or several hundred columns.

[0089] A set of light elements 402 comprises the light elements capable of forming elementary light beams, or pixels, composing the first emission zone 302 described previously. The number of light elements 402 thus depends on the vertical spread and the horizontal spread of the emission zone 302. In practice, the set of light elements 402 may comprise a hundred or several hundred light elements 401 whose elementary light beams compose the emission zone 302. The set of light elements 402 is thus predefined, and the coordinates of the light elements of the set 402 in the matrix source 122, may be stored in a memory of the projector 110, in particular in a memory of the control module 111 described previously.

[0090] As indicated previously, it is necessary, in the emission zone 302, or in a part of the emission zone 302, to ensure a light intensity greater than the minimum threshold associated with the gantry point included in the emission zone 302, the minimum threshold possibly being of the order of 130 candelas.

[0091] Figures 5a and 5b show two examples of control of the light elements of the predefined set 402.

[0092] According to a first example illustrated in [Fig.5a], a group 501 of light elements forming a limited number of consecutive lines of light elements (3 lines in the first example) are activated within the predefined set 402, that is to say that the light elements of the group 501 are associated with a non-zero duty cycle value, the other light elements of the predefined set 402 being off, therefore associated with a zero duty cycle value.

[0093] The first example makes it possible to ensure a light intensity greater than the minimum threshold of the regulatory point, in a narrow zone around the regulatory point (portal point in particular), in particular narrow vertically. However, in order to to ensure that the regulatory point is well lit by the group 501, it is necessary to carry out a very precise calibration when mounting the first light module 120 in the projector 101. The solution proposed by the first example is therefore not optimal.

[0094] According to a second example, illustrated in [Fig.5b], a group 502 of light elements widened vertically relative to the group 501 can be activated within the emission zone 302. For this purpose, in the second example, the widened group 502 comprises 5 lines of light elements and no longer 3 lines as for the group 501. The advantage of the second example is to require a calibration that is less demanding in terms of precision, since the margin allowed by the vertical thickness of the group 502 is greater. However, even by assigning a non-zero minimum duty cycle value to each of the light elements of the group 502, the light intensity associated with the group 502 is high, which certainly makes it possible to ensure a light intensity greater than the minimum threshold associated with the regulatory point, but which creates a risk of non-compliance if the group 502 illuminates in the regulatory zone 303 described above.Indeed, the elementary lighting beams of the light elements 401 of the group 502 are not completely separate, and partially overlap, due to a lack of intrinsic precision of the light elements of a monolithic matrix source and the resolving power of the optical element 123.

[0095] The present invention, embodiments of which are shown with reference to Figures 6a to 6c, makes it possible to overcome the drawbacks of the first example and the second example of Figures 5a and 5b, as well as the drawbacks of the prior art. To this end, the invention proposes to control the matrix source to activate several groups of light elements in the predefined set 402, each group being separated from the other groups by light elements turned off, or deactivated, by the control. No restriction is attached to the number of groups of elements, which is any integer greater than or equal to 2 according to the invention. Thus, within a group, all the light elements are activated at a non-zero duty cycle value, and the light elements between the groups are turned off (zero duty cycle value).

[0096] Preferably, two consecutive groups are separated by: - a set of N lines of extinguished light elements, N being greater than or equal to 3, preferably equal to 1; or - a set of N columns of extinguished light elements, N being greater than or equal to 3, preferably equal to 1; or - a set of N diagonals of extinguished luminous elements, N being greater than or equal to 3, preferably equal to 1 or 2.

[0097] No restriction is attached to the number of light elements in each group of activated light elements, which is preferably less than 50, preferably less than 20, for example less than 15.

[0098] Due to the intrinsic imprecision of the elementary light beam of each light element, it is possible to obtain a relatively homogeneous intensity within an area comprising the groups of light elements, if the groups of light elements are close enough to each other so that the blurring of the pixels creates continuity between the light beams of the different groups. For example, in the case of the high-definition monolithic light source mentioned above, and for a spatial frequency of one pixel, a modulation transfer function of the matrix source less than 0.1 makes it possible to ensure sufficient blurring for homogeneous illumination of the area by the groups of light elements. The modulation transfer function, also called MTF for “Modulation Transfer Function” in English, is a function which characterizes the quality of an optical system, in particular its capacity to restore contrast.

[0099] It is thus made possible to illuminate a luminous zone as large as that of the group 502, but with fewer activated luminous elements than within the group 502. This allows finer control of the luminous intensity in the regulatory emission zone 302, while being robust to calibration errors when mounting the first lighting module 120 in the projector 110.

[0100] Note that no restriction is attached to the duty cycle values ​​assigned to the activated light elements of the groups thus formed: - within the same group, the cyclical ratios may be identical or may vary; and - the duty cycle values ​​in a first group may be identical to the duty cycle values ​​in a second group. Alternatively, the duty cycle values ​​vary between the different groups formed.

[0101] [Fig.6a] illustrates the control of groups of light elements of the predefined set 402 of light elements of a matrix light source of a lighting module, according to a first embodiment.

[0102] In the first embodiment, the predefined set 402 comprises groups of light elements 601.1, 601.2 and 601.3 whose light elements are activated, each group comprising a line of light elements. All light elements which are not shaded in the figure, and which are therefore outside the three groups, are controlled so as to be switched off. No restriction is attached: - the number of groups of elements each forming a line, three groups being shown for illustration purposes in [Fig.6a]; - the number of light elements in each group forming a line.

[0103] In the first embodiment, each group forming a line is separated from another group by a single line of unlit light elements. Alternatively, each group may be separated from another group by two or three lines of unlit light elements.

[0104] According to the first embodiment, each group may alternatively comprise two consecutive lines of activated light elements.

[0105] According to another variant of the first embodiment, each group can comprise a single column of light elements, or two consecutive columns of light elements, in the predefined set 402.

[0106] [Fig.6b] illustrates the control of groups of light elements of the predefined set 402 of light elements of a matrix light source, according to a second embodiment.

[0107] In the second embodiment, the groups form a checkerboard, i.e., a matrix of light element groups is formed, comprising at least two rows of groups and two columns of groups. In the example of [Fig.6b], the matrix of light element groups comprises two rows of groups and four columns of groups, thus forming eight groups 601.1, 601.2, 601.3, 601.4, 601.5, 601.6, 601.7 and 601.8.

[0108] In the second embodiment, each group 601.1-601.8 is separated from the group to its right or left by a single column of unlit light elements. Alternatively, several columns, for example two or three columns, of unlit light elements separate two groups next to each other.

[0109] Similarly, each group 601.1-601.8 is separated from the group above or below it by a single line of unlit light elements. Alternatively, several lines, for example two or three lines, of unlit light elements separate two groups above each other.

[0110] No restriction is attached to the number of light elements in each group. In the example of [Fig.6b], each group comprises four activated light elements, distributed in a square. No restriction is also attached to the distribution of the activated light elements in each group. According to the second embodiment, each group may comprise a single activated light element, and the light elements each forming a group are thus distributed in a checkerboard pattern in at least part of the predetermined set 402.

[0111] [Fig.6c] illustrates the control of groups of light elements of the predefined set 402 of light elements of a matrix light source of a lighting module, according to a third embodiment.

[0112] In the third embodiment, the predefined set 402 comprises groups of light elements 621.1-621.5 whose light elements are activated, each group comprising a diagonal of light elements. Five groups 621.1 to 621.5 are shown in [Fig.6c], as an example. In the third embodiment, the groups may have a number of distinct elements, depending on the position of the group in the set 402. All light elements which are not shaded in the figure, and which are therefore outside the three groups, are controlled so as to be switched off. No restriction is attached: - the number of groups of elements each forming a diagonal, five groups being shown for illustration purposes in [Fig.6c]; - the number of light elements in each group forming a diagonal.

[0113] In the third embodiment, each group forming a diagonal is separated from another group by two diagonals of extinguished light elements. Alternatively, each group may be separated from another group by three or four diagonals of extinguished light elements.

[0114] According to the third embodiment, each group may alternatively comprise two consecutive, or adjacent, diagonals of activated light elements.

[0115] It is thus understood from the embodiments given above that a group of light elements comprises adjacent light elements, each light element of the group being adjacent to at least one other element of the group.

[0116] [Fig.7] is a diagram illustrating the steps of a method for controlling a matrix light source, by the control module 111 described previously, according to embodiments of the invention.

[0117] In a step 700, the control module 100 receives at least one command to activate or deactivate at least one lighting function, the activation or deactivation command possibly comprising one or more parameters. For example, a command to activate the ADB function may be received in step 701, accompanied by a position of another vehicle detected in front of the vehicle in which the lighting system 100 is integrated.

[0118] In a step 701, the control module 100 checks whether the at least one activation or deactivation command received satisfies one or more predefined conditions for activating the groups of light elements of the predefined set 402. For example, in the example described previously, the control module 100 can check the following activation conditions: - that the command is an ADB activation command comprising at least one deactivated segment in the high beam; - that a regulatory point associated with a minimum intensity threshold, such as a gantry point, is associated with a position of said at least one deactivated segment.

[0119] If the activation condition(s) are not satisfied, then the control module 111 executes the activation or deactivation command, in a known manner, at a step 702. For example, the execution of the command according to step 702 can to understand: - sending a first control signal to the first lighting module 120 to perform a function such as the display of a pictogram for example, or to complete a function performed by the second lighting module 130; and / or - sending a second control signal to the second lighting module 120, to activate or deactivate a lighting function, such as the low beam function LB, or the high beam function HB, with optionally the deactivation of a segment (but which does not include a regulatory point).

[0120] On the other hand, if each of the at least one activation condition is satisfied in step 701, then the control module 111 activates, in a step 703, the groups of light elements of the predefined set 402, as described previously, in general or with reference to the three embodiments. The coordinates of the light elements forming the groups can be predefined and stored in a memory of the control module 111, in order to generate the digital image making it possible to activate the groups of light elements of the predefined set. Furthermore, in step 703, the control module 111 can execute the activation or deactivation command. For example, the execution of the command in step 703, can comprise, as for step 701: - sending a first control signal (the digital image) to the first lighting module 120 to perform a function such as displaying a pictogram for example, or to complete a function performed by the second lighting module 130; and / or - sending a second control signal to the second lighting module 120, to activate or deactivate a lighting function, such as the low beam function LB, or the high beam function HB, with optional deactivation according to ADB of a segment (but which does not include a regulatory point).

[0121] [Fig.8] illustrates the structure of a control module, such as the control module 111, of a matrix source 122, according to embodiments of the invention.

[0122] The control module 111 comprises a processor 801 configured to communicate unidirectionally or bidirectionally, via one or more buses or via a direct wired connection, with a memory 802 such as a memory of the “Random Access Memory” type, RAM, or a memory of the “Read Only Memory” type, ROM, or any other type of memory (Flash, EEPROM, etc.). Alternatively, the memory 802 comprises several memories of the aforementioned types.

[0123] The memory 802 is capable of storing, permanently or temporarily, at least some of the data used and / or resulting from the implementation of the steps of the method according to the invention illustrated with reference to [Fig.7].

[0124] In particular, the memory 802 may be capable of storing the pre-condition(s) defined activation times of the groups of light elements of the predefined set, as well as the respective positions of the light elements of the groups in the predefined set, associated with predetermined duty cycle values. Such data can be stored before commissioning of the control module 111, prior to its installation in the headlight 110 of the vehicle.

[0125] The processor 801 is capable of executing instructions, stored in the memory 802, for implementing the steps 700 to 703 described previously. Alternatively, the processor 801 can be replaced by a microcontroller designed and configured to carry out the steps 700 to 703 described previously.

[0126] The control module 111 comprises a first interface 803 capable of communicating with the central control module 101, in particular to receive commands for activating or deactivating at least one light control, with optionally one or more parameters.

[0127] The control module 111 comprises a second interface 804 capable of communicating with the first lighting module 120, in particular for the transmission of the first control signal, which may comprise the duty cycle values ​​of the light elements of the groups of the predefined set 402.

[0128] The control module 111 comprises a third interface 805 capable of communicating with the second lighting module 130 in particular for the transmission of the second control signal described previously.

[0129] The present invention is not limited to the embodiments described above as examples; it extends to other variants.

Claims

Claims

1. A method for controlling a matrix light source (122) of a lighting module (120), the matrix light source comprising a plurality of individually controllable light elements (401), wherein a predefined set (402) of light elements of the matrix light source is capable of projecting a light beam into an emission zone (302) comprising a regulatory point associated with a minimum light intensity threshold, the method comprising: - upon receipt (700) of a command to activate or deactivate at least one light function, verification (701) that the command satisfies at least one condition for activating light elements of the predefined set; - if the command satisfies each activation condition among said at least one activation condition, activation (703) of groups (601.1-601.3; 611.1-611.8; 621.1-621.5) of light elements included in the predefined set of light elements, so as to project a light beam onto the regulatory point at a light intensity greater than the minimum light intensity threshold; wherein each group of light elements comprises adjacent light elements in the predefined set, and wherein the groups are separated by deactivated light elements.

2. Method according to claim 1, in which the regulatory point is a gantry point, and in which, when the predefined assembly (402) projects the light beam onto a screen, the regulatory point is included in a pixel of the projected beam lying vertically between 1° and 3°, in particular between 1.5° and 2.5°.

3. The method of claim 2, wherein the lighting module (120) comprising the matrix light source (122) is a first lighting module of a lighting system further comprising a second lighting module (130) adapted to project an adaptive segmented high beam (150), and wherein the at least one activation condition comprises the following activation conditions: - the command is an activation command of the adaptive segmented high beam, indicating a deactivation of at least one segment (151.2) of the segmented high beam; - the at least one deactivated segment of the segmented high beam defines a tunnel (301) of absence of light emission including the regulatory point.

4. Method according to one of the preceding claims, in which the set (402) of luminous elements is predefined so that, when the light beam of the predefined set is projected onto a screen, the emission zone (302) extends horizontally between a first horizontal position and a second horizontal position, a first deviation between the first horizontal position and the regulatory point being less than 1° and / or a second deviation between the second horizontal position and the regulatory point being less than 1°.

5. Method according to one of claims 1 to 4, wherein the light elements (401) of the matrix light source (122) are arranged in rows and columns, and wherein each group (601.1-601.3; 611.1-611.8; 621.1-621.5) of light elements comprises M light elements, M being an integer less than or equal to 50, in particular less than 20, and preferably less than 15.

6. Method according to one of the preceding claims, wherein the light elements (401) of the matrix light source (122) are arranged in rows and columns, and wherein each group (601.1-601.3) of light elements comprises N rows of light elements from the predefined set, N being between 1 and 3, two groups above each other being separated by at least one row of deactivated light elements and by at most four rows of deactivated light elements.

7. Method according to claim 5, wherein the groups (611.1-611.8) of activated light elements are distributed in a checkerboard pattern in the predefined set (402), and wherein each group comprises less than 10 light elements, in particular less than 5 light elements.

8. Method according to one of claims 1 to 5, wherein the light elements (401) of the matrix light source (122) are arranged in rows and columns, and wherein each group (621.1-621.5) of light elements comprises N diagonals of light elements of the predefined set, N being between 1 and 3, two consecutive groups being separated by at least two diagonals of deactivated light elements and by at most three diagonals of deactivated light elements.

9. Method according to one of the preceding claims, in which the light elements (401) of the matrix light source (122) are of submillimeter dimensions and are epitaxially grown directly on a common substrate.

10. Computer program comprising instructions for implementing the method according to one of the preceding claims, when these instructions are executed by a processor (801).

11. Control module (111) of a lighting module (120) comprising a matrix light source (122) comprising a plurality of individually controllable light elements (401), the control module comprising a memory (802) storing positions of a predefined set (402) of light elements of the matrix light source capable of projecting a light beam in an emission zone (302) comprising a regulatory point associated with a minimum threshold of light intensity, the control module comprising a processor (801) configured to: - upon receipt, via a first interface (803), of a command for activating or deactivating at least one light function, verify that the command satisfies at least one condition for activating light elements of the predefined set;- if the command satisfies each activation condition among said at least one activation condition, transmitting a control signal to the lighting module to command an activation of groups (601.1-601.3; 611.1-611.8; 621.1-621.5) of light elements included in the predefined set of light elements, so as to project a light beam onto the regulatory point at a light intensity greater than the minimum light intensity threshold; wherein each group of light elements comprises adjacent light elements in the predefined set, and wherein the groups are separated by deactivated light elements;

12. Lighting system (100) for a motor vehicle, comprising a control module (111) according to claim 11 and a lighting module (120) comprising a matrix light source comprising a plurality of individually controllable light elements (401).

13. Lighting system (100) according to claim 12, further comprising at least one further lighting module (130), capable of projecting a dipped beam of light (160) to perform a dipped beam function and / or capable of projecting a high beam of light (150) to perform a high beam function.

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