Lighting device for motor vehicles and method for controlling such a lighting device

Abstract

The invention relates to a lighting device (1) comprising: - a main laser source (11A) having an emission spectrum predominantly between 500 nm and 578 nm and at least one additional laser source (11B, 11C) producing an emission spectrum different from that of the first laser source (11A) and - a control unit (15) configured to modify the light power emitted by the main and additional laser sources when the ambient brightness is above a predetermined threshold, so that the final total light power is less than or equal to the initial total light power, the sum of the final additional light powers is less than the sum of the initial additional light powers, and the final main light power is greater than the initial main light power.The invention also relates to a method for controlling the lighting device, as well as a vehicle comprising the lighting device. Figure to be published with the abstract: Fig. 1.

Description

Title of the invention: Lighting device for a motor vehicle and method for controlling such a lighting device

[0001] The technical context of the present invention is that of motor vehicle equipment. More particularly, the invention relates to a lighting device for a motor vehicle and a method for controlling such a lighting device. The invention also relates to a motor vehicle comprising such a lighting device, the lighting device being able to be controlled by such a control method.

[0002] In the state of the art, the use of techniques for projecting light information onto a support acting as a projection surface is known. The information is then projected by a lighting device comprising one or more light sources which project an image onto the support.In this case, a known disadvantage lies in the lack of contrast between the image projected onto the support and the natural illumination of the support itself, due to its illumination by light sources - natural or artificial - other than those which allow the formation of the projected image. For example, in the case of daytime use, the illumination due to incident sunlight may be much higher than that due to the light source(s) allowing the formation of the projected image, which leads to insufficient contrast to be able to display and / or see the projected image comfortably.

[0003] Indeed, it is considered that a contrast is sufficient to allow comfortable reading of the light information thus projected if the illumination received by the projection support and coming from the light source(s) generating said light information is at least equal to one and a half times the illumination of said support coming from other light sources, such as in particular from sunlight or one or more other sources of artificial illumination.

[0004] It is known to use laser sources for projection applications in a motor vehicle interior or outside the motor vehicle, in the vicinity of said motor vehicle. A known disadvantage of using such laser sources lies in the fact that direct observation of the laser source is dangerous and induces a significant ocular risk for passengers of the motor vehicle or for persons located in the direct vicinity. For this reason, many national laws restrict the use of such laser sources by limiting the light powers emitted. More particularly, the laser sources authorized for such uses are limited to those of classes 1 or 2.

[0005] A known drawback then lies in the fact that the luminous power available by such classes of laser sources does not allow sufficient contrasts and / or illumination to be obtained, depending on the applications and lighting conditions considered.

[0006] The object of the present invention is to propose a lighting device making it possible to respond at least to a large extent to the preceding problems and to further lead to other advantages.

[0007] Another object of the invention is to improve the projection of an image inside a motor vehicle or outside said motor vehicle using a light device comprising a light emission assembly comprising several laser sources.

[0008] Another aim of the invention is to improve the contrast and / or the illumination provided by the light emitting assembly without increasing the ocular risk.

[0009] According to a first aspect of the invention, at least one of the aforementioned objectives is achieved with a lighting device for a motor vehicle intended to project an image, the lighting device comprising: - a light emission assembly comprising a main laser source, configured to generate a main light beam having a main light power and an emission spectrum predominantly between 500 nm and 578 nm and at least one additional laser source, each additional laser source being configured to generate an additional light beam having an additional light power and an emission spectrum different from that of the main laser source, said main laser source and said at least one additional laser source being selectively controllable and the light emission assembly being configured to emit a total light power resulting from the sum of the main and additional light powers; - a brightness sensor capable of measuring ambient brightness; - a control unit configured to, when the measured ambient brightness is greater than a predetermined ambient brightness threshold, modify an initial total light power emitted by the light emitting assembly and formed by the sum of an initial main light power emitted by the main laser source and one or more initial additional light powers emitted by each of the additional laser sources, into a final total light power emitted by the light emitting assembly and formed by the sum of a final main light power emitted by the main laser source and one or more final additional light powers emitted by each of the additional laser sources; the final total luminous power being less than or equal to the initial total luminous power, the sum of the final additional light powers of the additional laser sources being less than the sum of the initial additional light powers of the additional laser sources, and the final main light power of the main laser source being greater than the initial main light power of said main laser source.

[0010] In the context of the present invention, the light emission assembly comprises several light sources: the main laser source and one or more additional laser sources. The light emission assembly is of class II or lower. For example, each laser source is a class II or lower laser source. Each laser source - main or additional - is preferably of the monochromatic source type, that is to say characterized by an emission spectrum sufficiently narrow to cover mainly the wavelengths relating to a single color.

[0011] Preferably, the main laser source is configured to emit an emission spectrum predominantly between 500 nm and 578 nm, i.e. a median wavelength of the emission spectrum of the main laser source and / or the wavelength corresponding to the maximum light power emitted by the main laser source is located between 500 nm and 578 nm. The main laser source therefore emits green light.

[0012] In a first case, the light emission assembly may comprise a single additional laser source. It is then understood that in this case, the initial total light power is formed by the sum of the initial main light power and the initial additional light power emitted by the additional laser source. Similarly, the final total light power is formed by the sum of the final main light power and the final additional light power emitted by the additional laser source. It is also understood that the sum of the final additional light powers of the additional laser sources then corresponds to the final additional light power of the additional laser source and the sum of the initial additional light powers then corresponds to the initial additional light power of the additional laser source.Thus, it will be understood that the characteristic according to which "the sum of the final additional light powers of the additional laser sources is less than the sum of the initial additional light powers of the additional laser sources" means that the final additional light power of the additional laser source is less than the initial additional light power of the additional laser source.

[0013] In a second case, the light emission assembly may comprise a plurality of additional laser sources. As will be seen later, the different additional laser sources may in particular have different emission spectra.

[0014] In this second case, according to a first possibility, the light power of only a part of the plurality of additional laser sources can be reduced - partially or totally -, the light power of the other additional laser sources remaining unchanged, in order to verify the condition according to which "the sum of the final additional light powers of the additional laser sources is less than the sum of the initial additional light powers of the additional laser sources". For example, if the light emission assembly comprises two additional laser sources, then only the additional light power of one of the additional laser sources can be reduced, while the additional light power of the other additional laser source remains unchanged.

[0015] According to a second possibility, the light powers of each of the additional laser sources can be reduced - partially or totally - in order to verify the condition according to which "the sum of the final additional light powers of the additional laser sources is less than the sum of the initial additional light powers of the additional laser sources". For example, if the light emission assembly comprises two additional laser sources, then the additional light power of each of the additional laser sources is reduced.

[0016] In the context of the present invention, the main laser source and each of said additional laser sources preferably comprise laser diodes. In particular, the main laser source and / or each additional laser source comprises one or more laser diodes in order to generate the light rays corresponding to the expected light power.

[0017] In the context of the present invention, each laser source forming the light emission assembly is selectively controllable, that is to say that each laser source - main and additional(s) - is controllable independently of the other laser source(s) forming the light emission assembly. In particular, each of the laser sources can be activated or deactivated independently of the activation or deactivation of the other laser sources. Thus, the light emission assembly is configured to selectively control an outgoing light flux for each main laser source and each additional laser source, independently of each other.

[0018] In the context of the present invention, the main laser source and the at least one additional laser source each emit light rays according to a respective light power, the main light power for the main laser source and an additional light power for each of the additional laser sources. tional. The total light power emitted by the light emitting assembly is equal to the sum of all the light powers emitted by each laser source, i.e. the sum of the main light power emitted by the main laser source and the additional light power(s) each emitted by each additional laser source.

[0019] In the context of the present invention, the brightness sensor is configured to measure the ambient brightness in the vicinity of a projection surface of the light emitting assembly, i.e. in the vicinity of a projection support on which the image is projected from the light beams generated by the main laser source and / or the at least one additional laser source. By way of non-limiting example, the brightness sensor comprises a photodiode or any photosensitive sensor.

[0020] In the context of the present invention, the control unit is configured to control the light emission assembly, and in particular each of the main and additional laser sources, so as to modulate the main and additional light powers. Thus, the control unit makes it possible to modify the contribution of each of the main and additional laser sources to the light beam formed by the light emission assembly as a function of the ambient brightness measured by the brightness sensor. It will be noted that the light beam formed by the light emission assembly is itself formed by the main and additional light beams. In the context of the present invention, the control unit comprises a microcontroller and / or a printed circuit and / or a microprocessor. Additionally, the control unit also optionally comprises a memory.

[0021] In the context of the present invention, the adjective "initial" refers to a configuration of the emission assembly and / or a configuration of the main laser source and / or of the main light power and / or a configuration of each at least one additional laser source and / or of the additional light power(s) before the ambient brightness is greater than the predetermined ambient brightness threshold, that is to say, before the emission assembly is controlled by the control unit, or in other words, before modification of the light powers emitted by one and / or the other of the main and additional laser sources making up the emission assembly.

[0022] Conversely, the adjective “final” is used to describe a configuration of the emission assembly and / or a configuration of the main laser source and / or of the main light power and / or a configuration of each at least one additional laser source and / or of the additional light power(s) once the ambient brightness is greater than the predetermined ambient brightness threshold, i.e., after the emission assembly has been controlled by the control unit, or in other words, after modification of the light powers emitted by one and / or the other of the main and additional laser sources making up the emission assembly.

[0023] The image projected by the light device may in particular be a light pattern projecting light information. For example, the projected image may contain information on driving for the driver.

[0024] The lighting device according to the first aspect of the invention solves the technical problem in that it improves the light contrast of the image projected by the lighting device onto a projection support located inside a motor vehicle or outside said motor vehicle, without increasing the ocular risk. Indeed, the main laser source has an emission spectrum predominantly between 500 nm and 578 nm, corresponding to an emission spectrum in the green, and the eye is more sensitive to these wavelengths than to other wavelengths in the visible spectrum. Thus, when the ambient brightness is greater than the predetermined ambient brightness threshold, the control unit makes it possible to increase the main light power emitted by the main laser source and to reduce the additional light power(s) emitted by the additional laser source(s).The final total light beam emitted by the light emitting assembly and formed by the combination of the final main light beam and the final additional light beam(s) then has a spectrum comprising a greater proportion of wavelengths between 500 nm and 578 nm than the initial total beam. As the human eye is more sensitive to these wavelengths than those emitted by the additional laser source(s), the perception of the image formed by the emitting assembly is improved.

[0025] In addition, the final total light power is less than or equal to the initial light power. This means that the change in the main and additional light powers is made without increasing the total light power. The reduction in the additional light power(s) compensates for the increase in the main light power. Since the total light power is not increased, the ocular risk is not increased.

[0026] Thus, thanks to the invention, the projected image will be better perceived by an observer, because the total light beam emitted has a spectrum comprising more wavelengths between 500 nm and 578 nm. In addition, since the total light power does not increase, eye safety is guaranteed. There is therefore better visibility of the projected image, without the eye risk being increased.

[0027] The transmission assembly according to the first aspect of the invention may comprise at least one of the technical characteristics below, these technical characteristics being able to be taken alone or in combination.

[0028] According to an alternative, the light emission assembly comprises several additional laser sources including a first additional laser source having an emission spectrum mainly between 620 nm and 700 nm and a second additional laser source having an emission spectrum mainly between 430 nm and 500 nm.

[0029] By "a first additional laser source having an emission spectrum predominantly between 620 nm and 700 nm" is meant that a median wavelength of the emission spectrum of the first additional laser source and / or the wavelength corresponding to the maximum light power emitted by the first additional laser source is located between 620 nm and 700 nm. The first additional laser source therefore emits red light.

[0030] By "a second additional laser source having an emission spectrum predominantly between 430 nm and 500 nm" is meant that a median wavelength of the emission spectrum of the second additional laser source and / or the wavelength corresponding to the maximum light power emitted by the second additional laser source is located between 430 nm and 500 nm. The second additional laser source therefore emits blue light.

[0031] Thus, the light emitting assembly makes it possible to emit a light beam comprising red, green and blue components. The light device can thus project a color image. The color of the projected image can also change over time. The color of the projected image can thus be controlled.

[0032] According to an alternative, the lighting device comprises an oscillating mirror configured to oscillate between several positions and to reflect the main light beam emitted by the main laser source and the additional light beams emitted by the additional laser sources in order to form said image.

[0033] According to an alternative, when the initial total light power is changed to the final total light power, the final additional light power of each of the additional laser sources is less than the final main light power.

[0034] According to an alternative, when the initial total light power is modified into the final total light power, the sum of the final additional light powers is less than the final main light power.

[0035] According to an alternative, when the measured ambient brightness is greater than a predetermined ambient brightness threshold, i.e. when the initial total light power is modified into the final total light power, the control unit is configured to turn off each additional laser source.

[0036] According to an alternative, the predetermined ambient brightness threshold corresponds to a luminous power greater than or equal to one third of the total luminous power initial, and less than or equal to the initial total light power.

[0037] According to a second aspect of the invention, a method is proposed for controlling a lighting device for a motor vehicle in accordance with the first aspect of the invention.

[0038] The piloting method according to the second aspect of the invention comprises the following steps: - a step of measuring ambient brightness by the ambient brightness sensor; - a step of comparing the measured ambient brightness with a predetermined ambient brightness threshold; - if the measured ambient brightness is greater than the predetermined ambient brightness threshold, a step of modifying the initial total light power emitted by the light-emitting assembly and formed by the sum of an initial main light power emitted by the main laser source and one or more initial additional light powers emitted by each of the additional laser sources, into a final total light power emitted by the light-emitting assembly and formed by the sum of a final main light power emitted by the main laser source and one or more final additional light powers emitted by each of the additional laser sources, the final total light power being less than or equal to the initial total light power, the sum of the final additional light powers of the additional laser sources being less than the sum of the initial additional light powers of the additional laser sources, and the final main light power of the main laser source being greater than the initial main light power of said main laser source.

[0039] In the context of the present invention, the brightness measurement step is carried out by the brightness sensor of the lighting device according to the first aspect of the invention. As mentioned above, the brightness sensor comprises for example a photodiode or any photosensitive sensor. The ambient brightness is preferably measured near a projection surface of the light-emitting assembly, and preferably near a projection support on which the image formed by the lighting device is projected. Alternatively, the measurement step may take the form of a step of determining the ambient brightness, the determination step comprising a step of reading a brightness value available on an on-board network of the motor vehicle or on a remote server for example.Optionally, the measurement step is a measurement step of an illumination of the projection surface, or a determination step. of illumination of said projection surface.

[0040] In the context of the present invention, the step of comparing the measured brightness with a determined ambient brightness threshold is carried out by a calculation unit, comprising calculation means and / or storage means. By way of non-limiting example, the calculation unit comprises a microprocessor and / or a microcontroller and / or an integrated circuit.

[0041] The control method according to the second aspect of the invention is implemented by the control unit of the lighting device according to the first aspect of the invention. In the context of the present invention, the control unit may comprise a microcontroller and / or a printed circuit and / or a microprocessor. Additionally, the control unit may also comprise a memory. The control unit may comprise the calculation unit.

[0042] The modification step is carried out - at most - at constant light power of the light emitting assembly, so that the final total light power is less than or equal to the initial total light power. In other words, the light powers emitted by all or part of the main laser sources and additional laser source(s) are adjusted in a compensatory manner, so that the sum of the main and additional light powers remains invariant during the implementation of the control method, or so that the final total light power is less than the initial total light power. This advantageous configuration thus makes it possible to increase the contrast of the image projected onto the projection medium without danger to a human eye, due to the preponderance of the green component in the projected image.

[0043] The piloting method according to the second aspect of the invention may comprise at least one of the technical characteristics below, these technical characteristics being able to be taken alone or in combination.

[0044] According to an alternative, during the step of modifying the initial total light power into the final total light power, the final additional light power of each of the additional laser sources is less than the final main light power.

[0045] In other words, the final main light power is greater than each of the light powers of each additional laser source, taken independently of one another. This advantageous configuration makes it possible to make the light power produced by the main laser source greater than each of the light powers produced by the at least one additional laser source. Thus, in this advantageous configuration, the main laser source produces the dominant component of the light emitted by the light-emitting assembly, without however being the majority component in the light emitted by said light-emitting assembly. of non-limiting examples, if the main laser source emits in the green and the emission assembly comprises a first additional laser source emitting in the red and a second additional laser source emitting in the blue, then the modification step comprises a step of regulating the main laser source so as to increase the main light power - in the green - while the first additional laser source emitting in the red and the second additional laser source emitting in the blue are regulated so that their additional light power is reduced. This regulation is done so that the final main light power - corresponding to green - becomes greater than each of the final additional light powers - both in red and in blue, independently of each other;

[0046] According to an alternative, during the modification step, the sum of the final additional light powers is less than the final main light power. This advantageous configuration makes it possible to make the light power produced by the main laser source greater than the light power produced by the at least one additional laser source. Thus, in this advantageous configuration, the main laser source produces the dominant component of the light emitted by the light emission assembly, so that the light provided by the main laser source is in the majority in the light generated by the emission assembly. This advantageous configuration makes it possible to amplify the perception of the image formed by the laser source in the case of strong luminosity.By way of non-limiting examples, if the main laser source emits in the green and the emission assembly comprises only one additional laser source - emitting in the red or in the blue - then the modification step comprises a step of regulating the main laser source so as to increase the main light power - in the green - while the additional laser source emitting in the red or in the blue is regulated so that the additional light power is reduced. This regulation is carried out so that the final main light power - corresponding to green - is then greater than the final additional light power - corresponding to red or in blue.On the other hand, if the main laser source emits in the green and the emission assembly comprises a first additional laser source emitting in the red and a second additional laser source emitting in the blue, then the modification step comprises a step of regulating the main laser source so as to increase the main light power - in the green - while the first additional laser source emitting in the red and the second additional laser source emitting in the blue are regulated so that their additional light power is reduced. This regulation is done so that the final main light power - corresponding to green - becomes greater than the sum. final additional light powers - corresponding to red and blue;

[0047] According to an alternative, during the step of modifying the initial total light power into the final total light power, the additional laser sources are switched off. This advantageous configuration makes it possible to produce an image formed exclusively by the light rays generated by the main laser source, in a green spectral range. This configuration is particularly relevant in the case of maximum ambient brightness because it makes it possible to increase the light intensity of the image formed, by increasing the final main light power, but without increasing the total power emitted by the light-emitting assembly, that is to say, without exceeding critical power thresholds for a human eye, since the final additional light powers become zero.Optionally, in the case where the emission assembly comprises two additional laser sources, then it is possible that only one of the two additional laser sources is switched off when the light power of the main laser source is, concomitantly, increased. In the context of the present invention, all combinations of colors and additional sources are provided. Thus, for example, in the case where the light emission assembly comprises only one additional source - emitting light rays in the red or in the blue, then the modification step comprises a step of increasing the main light power emitted by the main laser source - emitting in the green - and a step of switching off the additional laser source; .

[0048] According to an alternative, the predetermined ambient brightness threshold corresponds to a light power greater than or equal to one third of the initial total light power, and less than or equal to the initial total light power. In other words, the predetermined ambient brightness threshold corresponding to the threshold from which the control unit acts on the light emission assembly in order to modify the light powers of the main laser source and / or of the at least one additional laser source is situated at a value between one third of an initial total light power and the initial total light power of the light device according to the invention.In other words, the threshold from which the control unit acts on the light emission assembly in order to modify the light powers of the main laser source and / or of the at least one additional laser source is located for a contrast value between 1:3 and 1:1.

[0049] The control method may optionally comprise several ambient brightness thresholds corresponding to several trigger thresholds of the control unit for regulating the light power of the main laser source and / or of the at least one additional laser source. At each of these trigger thresholds, a rule for controlling the light power of the main laser source and / or of the at least one additional laser source at least one additional laser source is associated, respecting the condition imposed by the modification step. However, for each of these trigger thresholds, the final light powers can be different depending on the desired contrast levels, for example.

[0050] According to an alternative, the predetermined ambient brightness threshold is between 1000 lux and 7000 lux. Preferably, the predetermined ambient brightness threshold is equal to 5000 lux.

[0051] Optionally, the lighting device according to the first aspect of the invention provides several predetermined ambient brightness thresholds and several rules for adjusting the light powers emitted by the main laser source and / or by the at least one additional laser source. By way of non-limiting example, if the ambient brightness is less than a first predetermined ambient brightness threshold - for example equal to 1000 lux - then the light power of the main laser source is between 50% and 65% of the total light power of the light emitting assembly; if the brightness is between the first predetermined ambient brightness threshold and a second predetermined ambient brightness threshold - for example equal to 5000 lux - then the light power of the main laser source is between 65% and 70% of the total light power of the light emitting assembly;if the ambient brightness is between the second predetermined ambient brightness threshold and a third predetermined ambient brightness threshold - for example equal to 7000 lux - then the light power of the main laser source is between 70% and 95% of the total light power of the emission assembly; and if the ambient brightness is greater than the third predetermined ambient brightness threshold, then the light power of the main laser source is between 95% and 100% of the total light power of the light emission assembly; ;

[0052] According to a third aspect of the invention, there is provided a motor vehicle comprising a lighting device according to the first aspect of the invention. In particular, the lighting device according to the first aspect of the invention comprises a control unit configured to implement the steps of the control method according to the second aspect of the invention.

[0053] The motor vehicle according to the third aspect of the invention comprises: - a support for projecting an image, such as all or part of a dashboard and / or an interior panel of a passenger compartment of the motor vehicle, and in particular a side door trim panel or quarter panels, and - a lighting device according to the first aspect of the invention, the lighting device being configured to project the image onto the projection medium.

[0054] Advantageously, the control unit of the light device is configured to implement the steps of the piloting method in accordance with the second aspect of the invention.

[0055] Various embodiments of the invention are provided, integrating according to all of their possible combinations the different optional characteristics set out here.

[0056] Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several exemplary embodiments given for informational and non-limiting purposes with reference to the appended schematic drawings on the other hand, in which:

[0057] [Fig-1] [Fig.l] illustrates a schematic view of a light device in accordance with first aspect of the invention;

[0058] [Fig.2] [Fig.2] is a diagram illustrating the method of controlling the device light illustrated in [Fig.l], and in accordance with the second aspect of the invention;

[0059] [Fig.3] [Fig.3] is a diagram showing the power distribution light from the laser sources of a light-emitting assembly of the light device illustrated in [Fig.l], at three different times.

[0060] Of course, the features, variants and different embodiments of the invention may be combined with each other, in various combinations, provided that they are not incompatible or mutually exclusive. In particular, variants of the invention may be imagined comprising only a selection of features described below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art.

[0061] In particular, all the variants and all the embodiments described can be combined with each other if nothing prevents this combination from a technical point of view.

[0062] In the figures, the elements common to several figures retain the same reference.

[0063] [Fig.l] illustrates a lighting device 1 for a motor vehicle intended to project an image onto a support. The lighting device 1 comprises a light emission assembly 14, a brightness sensor 16 and a control unit 15.

[0064] The light emission assembly 14 comprises a main laser source 1 IA, configured to generate a main light beam having a main light power and an emission spectrum predominantly between 500 nm and 578 nm. The main laser source 1 IA therefore emits green light.

[0065] The light emitting assembly 14 also comprises at least one additional laser source, each additional laser source being configured to generate an additional light beam having an additional light power and a emission spectrum different from that of the main laser source 1 IA. In the example illustrated, the light emission assembly 14 comprises a first additional laser source 1 IB and a second additional laser source 1 IC. It is understood that the light emission assembly 14 could alternatively comprise a single additional laser source or more than two additional laser sources, without departing from the scope of the invention.

[0066] The main laser source 11A, and the first and second additional laser sources 11B, 11C have emission spectra that are different from each other, and different from that of the main laser source 11A. For example, the first additional laser source 11B may have an emission spectrum that is predominantly between 620 nm and 700 nm and the second additional laser source 11C may have an emission spectrum that is predominantly between 430 nm and 500 nm. The first additional laser source therefore emits a red light, while the second additional laser source emits a blue color. It is understood that the additional laser sources. It is understood that the additional laser sources could have different emission spectra without departing from the scope of the invention.

[0067] The main laser source 11A and the additional laser sources 11B, 11C can be selectively controlled, in particular by the control unit 15. In particular, each of the main laser sources 11A, and additional laser sources 11B, 11C can be activated or deactivated independently of the activation or deactivation of the other main laser sources 11A, and additional laser sources 11B, 11C.

[0068] The main laser source 11A is configured to generate a main light beam 10A, the first additional laser source 11B is configured to generate a first additional light beam 10B and the second additional laser source 11C is configured to generate a second additional light beam 10C.

[0069] In [Fig.l], each laser source 11A, 11B, 11C of the light emission assembly 14 is associated with collimation optics in order to shape and orient the light rays emitted by the laser sources 11A, 11b, 11C. In particular, the emission assembly 14 comprises: - a first collimation optic 12A associated with the main laser source 11A and making it possible to collimate the main light beam 10A emitted by the main laser source 11A; - a second collimation optic 12B associated with the first additional laser source 1B and making it possible to collimate the first additional light beam 10B emitted by the first additional laser source 1B; - a third 12C collimation optic associated with the second additional laser source 1 IC and allowing the second additional light beam to be collimated 10C emitted by the second additional laser source 1 IC.

[0070] The lighting device 1 also comprises an oscillating mirror 13. Once collimated, the main light beams 10A, and additional 10B, 10C are sent towards the oscillating mirror 13. The main light beam 10A and the first additional light beam 10B are returned towards the oscillating mirror 13 after reflection on a semi-reflecting plate, while the second additional light beam 10C is sent towards the oscillating mirror 13 through the semi-reflecting plates. The use of the semi-reflecting plates makes it possible to make the lighting device compact. It is understood that another arrangement of the main laser sources 11A and additional 11B, 11C could be possible, as long as the main light beams 10A and additional 10B, 10C are returned towards the oscillating mirror 13.

[0071] The oscillating mirror 13 is configured to oscillate between several positions and to reflect the main light beam 10A emitted by the main laser source 11A and the additional light beams 10B, 10C emitted by the additional laser sources 11B, 11C in order to form the projected image.

[0072] The oscillating mirror 13 comprises a mechanical device for oscillating the oscillating mirror 13, in order to orient the main light beams 10A and additional light beams 10B, 10C incident. The oscillating mirror 13 can oscillate along a fast axis and a slow axis, extending perpendicular to the fast axis. The fast axis of the oscillating mirror 13 corresponds to the axis around which the oscillating mirror 13 is in resonance and oscillates. The slow axis is linked to a mechanical detachment of the oscillating mirror 13. The oscillating mirror 13 is thus configured to take a plurality of different angular orientations and to pass from one to the other of these angular orientations at very high frequency. The oscillating mirror 13 is for example a MEMS device - an English acronym for "Microelectromechanical System" meaning microelectromechanical system - making it possible to orient each of the incident light beams according to a plurality of angular orientations over time.For each position of the oscillating mirror 13, the main light beam 10A and additional light beam(s) 10B, 10C are returned in a given direction and form a primary image. The image projected by the light device 1 inside the vehicle or outside the vehicle is then formed by the superposition of all the primary images formed. Indeed, due to the retinal persistence of the observer, the latter does not distinguish the primary images, but perceives the image resulting from the superposition of the primary images.

[0073] The projection support onto which the image formed by the light device 1 is projected may be located inside or outside the motor vehicle in which the light device is arranged. In the case where it is located outside the motor vehicle, it may for example be formed by a bodywork element of the vehicle or by the road on which the vehicle is traveling, and in particular by a ground surface located near the motor vehicle, that is to say for example within a radius of 10 meters around said motor vehicle. In the case where it is located inside the vehicle, it may for example be formed by all or part of a dashboard, and / or an interior panel of a passenger compartment of the motor vehicle, and in particular side door trim panels or quarter panels.

[0074] The invention also relates to a motor vehicle comprising the image projection support such as all or part of a dashboard and / or an interior panel of a passenger compartment of the motor vehicle, and in particular a side door trim panel or quarter panels, and the lighting device 1, the lighting device being configured to project the image onto the projection support. The control unit 15 of the lighting device 1 can then be configured to implement the steps of the control method which will be described below.

[0075] The brightness sensor 16 is capable of measuring ambient brightness in the motor vehicle or outside said motor vehicle, in the vicinity thereof. In particular, the brightness sensor 16 is capable of measuring ambient brightness in the vicinity of the projection support.

[0076] The light emitting assembly 14 emits a total light power resulting from the sum of the main and additional light powers. In the illustrated example, the total light power results from the sum of the main light power emitted by the main laser source 11A, the first additional light power emitted by the first additional laser source 11B, and the second additional light power emitted by the second additional laser source 11C.

[0077] The control unit 15 is electrically connected to the brightness sensor 16 and to the light emission assembly 14, so as to be able to control the main laser source 11A and the additional laser sources 11B, 11C as a function of the measured ambient brightness.

[0078] In particular, one control unit 15 is configured to, when the measured ambient brightness is greater than a predetermined ambient brightness threshold, modify an initial total light power emitted by the light emitting assembly 14 into a final total light power emitted by the light emitting assembly.

[0079] The initial total light power emitted by the light emitting assembly is formed by the sum of an initial main light power emitted by the main laser source 11A and the initial additional light powers emitted by the first and second additional laser sources 11B, 11C. The power final total light output emitted by the light emitting assembly is formed by the sum of a final main light power emitted by the main laser source 11A and the final additional light powers, emitted by each of the additional laser sources 11B, 11C.

[0080] When the control unit modifies the initial total light power, the initial light powers of the main laser source 11A and / or of the first and second additional laser sources 11b, 11C are modified so that: - the final total luminous power is less than or equal to the initial total luminous power, - the sum of the final additional light powers of the first and second additional laser sources 11B, 11C is less than the sum of the initial additional light powers of the first and second additional laser sources 11B, 11C, and - the final main light power of the main laser source 11A is greater than the initial main light power of said main laser source 11A.

[0081] It will also be seen subsequently that the control unit 15 can possibly modify the initial light powers of the main laser source 11A and / or of the first and second additional laser sources 11b, 11C so that the final additional light power of each of the additional laser sources is less than the final main light power; or even so that the sum of the final additional light powers is less than the final main light power.

[0082] Furthermore, when the measured ambient brightness is greater than a predetermined ambient brightness threshold, i.e. when the initial total light power is changed to the final total light power, the control unit 15 may possibly switch off all of the additional laser sources 11B, 11C.

[0083] [Fig. 2] illustrates the method of controlling the lighting device of [Fig. 1], in accordance with the second aspect of the invention. In particular, the control unit 15 is configured to implement the control method.

[0084] The control method comprises a step 20 of measuring the ambient brightness Lamb by the ambient brightness sensor 16.

[0085] The control method also comprises a step 21 of comparing the measured ambient brightness Lamb with a predetermined ambient brightness threshold L ambjS. The predetermined ambient brightness threshold LambjS may correspond to a light power greater than or equal to one third of the initial total light power, and less than or equal to the initial total light power.

[0086] The predetermined ambient brightness threshold is for example between 1000 lux and 7000 lux. Preferably, the brightness threshold may be equal to 5000 lux. If the measured ambient brightness Lamb is greater than the predetermined ambient brightness threshold Lamb>s, a step 25 of modifying the initial total luminous power Ptoti emitted by the light emitting assembly 14 into a final total luminous power Ptotf emitted by the light emitting assembly 14.

[0087] This modification of the initial total light power is done by modifying the light powers of the laser sources 11A, 11B, 11C of the light emission assembly 14. This modification is carried out by respecting the following conditions on the light powers emitted by the main laser sources 11A and additional laser sources 11B, 11C: - the final total luminous power PTotf, remains less than or equal to the initial total luminous power PToti, and - the sum of the final additional light powers PAlf, PA2f of the additional laser sources 1 IB, 1 IC is less than the sum of the initial additional light powers PAli, PA2i of the additional laser sources 11B, 11C and - the final main light power PPalf is greater than the initial main light power PPali.

[0088] In other words, the control unit 15 controls the light emission assembly 14 - and in particular the main laser source 11A and / or the additional laser sources 11B, 11C - so as to modify an initial total light power PToti emitted by the light emission assembly 14 and formed by the sum of the initial main light power PPali emitted by the main laser source 11A and the initial additional light powers PAli, PA2i emitted by each of the additional laser sources 11B, 11C into a final total light power PTotf, emitted by the light emission assembly 14 and formed by the sum of the final main light power PPalf emitted by the main laser source 11A and the final additional light powers PAlf, PA2f emitted by each of the additional laser sources 11B, 11C.

[0089] Furthermore, during the modification step 25, the total light power generated by the light emitting assembly 14, measured at the output S of the light device 1, remains at most constant. In other words, the light power of the final total light beam generated by the light emitting assembly 14 and taken at the output S of the light device 1 remains invariant or decreases when the method is implemented. Indeed, the light powers emitted by all or part of the laser sources 11A, 11B, HC - and in particular that of the main laser source 11A and / or those of the additional laser sources 11B, 11C - are adjusted in a compensatory manner, so that the total sum of the light powers remains invariant or decreases with the implementation of the control method 2.

[0090] In particular, the control unit 15 is configured to control a luminous flux produced by the light emitting assembly 14 so that, when the brightness measured by the brightness sensor 16 exceeds the predetermined ambient brightness threshold Lamb>s, the luminous flux generated by the main laser source 11A becomes greater in the total luminous flux generated by the light emitting assembly 14, without the total luminous flux being increased. The control unit 15 thus makes it possible to increase the main luminous power emitted by the main laser source and to reduce the additional luminous power(s) emitted by the additional laser source(s) in the total luminous power emitted, without the total power emitted being increased. The final total luminous beam emitted then has a spectrum comprising a greater proportion of wavelengths between 500 nm and 578 nm than the initial total beam.As the human eye is more sensitive to these wavelengths than those emitted by the additional laser source(s), the perception of the image formed by the emission assembly is improved.

[0091] In particular, when the brightness condition is verified, the control unit 15 can control the light emission assembly 14 so that the final additional light power PAlf, PA2f of each of the additional laser sources 11B, 11C is less than the final main light power PPalf.

[0092] In other words, the main light power generated by the main laser source 11A is made greater than each of the additional light powers generated by the additional laser sources 11B, 11C. In other words, the main light power generated by the main laser source 11A is greater than the first additional light power generated by the first additional laser source 11B and the main light power generated by the main laser source 11A is greater than the second additional light power generated by the second additional laser source 11C. The spectrum of the final total light beam then comprises more wavelengths between 500 nm and 578 nm, i.e. in the green, than in other parts of the visible spectrum. The projected image is thus more visible.

[0093] In a particular example, the control unit 15 can control the light emission assembly 14 so that the sum of the final additional light powers PAlf, PA2f is less than the final main light power PPalf.

[0094] In other words, the main light power generated by the main laser source 11A is greater than the sum of the first additional light power generated by the first additional laser source 11B and the second additional light power generated by the second additional laser source. 1 IC. The spectrum of the final total light beam then includes even more wavelengths between 500 nm and 578 nm, i.e. in the green range. In fact, more than half of the light rays forming the final total light beam come from the main laser source 11 A.

[0095] It is also possible for the control unit 15 to control the light emission assembly 14 so that the additional laser sources 11B, 11C are switched off. The light beam generated by the light emission assembly 14 is then exclusively composed of the light rays emitted by the main laser source 11A. The spectrum of the final total light beam then comprises even more wavelengths between 500 nm and 578 nm. Indeed, the final total light beam is only formed by the emission of the main light beam 10A coming from the main laser source 11A. The projected image is then green, and therefore more visible to the eye. Its contrast is therefore improved.

[0096] [Fig. 3] represents several examples A, B, C of repair of light powers of the laser sources 11 A, 11B, 11C, the examples being considered at different times, or illustrating different possible operating alternatives.

[0097] For each of the examples A, B, C, it is possible to observe in order, from left to right, the second additional light power PA2 emitted by the second additional laser source 1 IC, the main light power PPal emitted by the main laser source 1 IA, then the first additional light power PA1 emitted by the first additional light source 1 IB. It is recalled that, in the exemplary embodiments illustrated in [Fig. 3], the main laser source 1 IA is a source emitting green light, the first additional laser source 1 IB is a source emitting red light and the second additional laser source 1 IC is a source emitting blue light.

[0098] The first distribution example A illustrates the light powers emitted by the laser sources 11A, 11B, 11C in the initial state, that is to say before the control method has been applied.

[0099] It can be seen that the light emitting assembly 14 emits an initial total light power Ptoti of 300 mW resulting from the sum of the second initial additional light power PA2i emitted by the second additional laser source 1 IC, amounting to 150 mW, the initial main light power PPali emitted by the main laser source 1 IA amounting to 90 mW and the first initial additional light power PAli emitted by the first additional laser source 1 IB amounting to 60 mW. This initial total light power Ptoti is perceived by the eye as corresponding to an initial total light power of 3000 lux.

[0100] When the ambient brightness Lamb captured by the brightness sensor 16 is greater than the predetermined ambient brightness threshold Lamb,s, the control unit 15 modifies the distribution of the light beams emitted by the laser sources 11 A, 1 IB, 1 IC of the light emission assembly 14, and in particular the distribution of the light powers of the light beams.

[0101] Examples B and C illustrate power distributions of the light beams emitted by the laser sources 1 IA, 1 IB, 1 IC once the control unit has modified the light powers of the laser sources 11A, 11B, 11C, i.e. in the final state. This final state also corresponds to the state of the light device once the control method has been executed.

[0102] Example B illustrates a first example of modification of the distribution of the light beams, and of distribution of the light powers of the laser sources 11 A, 1 IB, 1 IC in the final state. In this example, the second additional light power PA2 and the first additional light power PA1 are reduced so that the second final additional light power PA2f is less than the second initial additional light power PA2i and the first final additional light power PAlf is less than the first initial additional light power PAli. It can be observed that the second additional light power PA2 goes from 150 mW to 110 mW, and that the first additional light power PA1 goes from 60 mW to 40 mW.

[0103] At the same time, the main light power PPal is increased, so that the final main light power PPalf is greater than the initial main light power PPali. It can be observed that the main light power PPal increases from 90 mW to 150 mW.

[0104] However, the total light power Ptot emitted remains constant. Indeed, the sum of all the light powers emitted by the laser sources 11 A, 1 IB, 1 IC remains equal to 300 mW. Only the total light power, corresponding to the power perceived by an observer, increases. It goes from 3000 lux to 4275 lux. Indeed, as the eye is more sensitive to green light and the quantity of green light has increased proportionally in the final beam, the total light power perceptible by the eye increases.

[0105] It is therefore understood that for the same energy power emitted by the light emission assembly 14, the light power perceptible by an observer increases.

[0106] It can be noted that in this example, the second final additional light power PA2f and the first final additional light power PAlf are both lower than the final main light power PPalf.

[0107] It can also be noted that the sum of the second final additional light power PA2f and the first final additional light power PAlf is equal to the final main light power PPalf.

[0108] In this example B, the second additional light power PA2 and the first additional light power PA1 have been reduced simultaneously. It is understood that it would be possible to reduce only one of these two powers, and to keep the other power constant, for example. However, the more the additional light powers decrease, the more it is possible to increase the main light power and thus make the projected image visible.

[0109] Example C illustrates a second example of modification of the repair of the light beams, and of distribution of the light powers of the laser sources 11 A, 1 IB, 1 IC in the final state. In this example, the second additional laser source 1 IC and the first additional laser source 11A are switched off, so that the second additional light power PA2 and the first additional light power PA1 are both zero.

[0110] At the same time, the main light power PPal is increased, so that the final main light power PPalf is greater than the initial main light power PPali. It can be observed that the main light power PPal increases from 90 mW to 300 mW. Thus, the total light power Ptot remains identical, and all the light power emitted by the light emitting assembly 14 is emitted by the main laser source which emits green light. The light power perceptible by an observer is then increased to its maximum. Indeed, it increases from 3000 lux to 7700 lux.

[0111] Examples B and C have been presented as alternatives for distributing the light powers emitted by the laser sources 11A, 11B, 11C. In other words, starting from the initial state illustrated by example A, it is possible to arrive at the distribution illustrated by example B or by example C. However, it may be noted that examples B and C can constitute two steps in the control method. That is to say, if the ambient brightness is greater than a first predetermined ambient brightness threshold, but less than a second predetermined brightness threshold, then the repair according to example B can be applied, and if the ambient brightness then becomes greater than the second predetermined ambient brightness threshold, then the distribution according to example C can be applied.

Claims

Claims

1. Luminous device (1) for a motor vehicle intended to project an image, the luminous device (1) comprising: - a light emission assembly (14) comprising a main laser source (1 IA), configured to generate a main light beam having a main light power and an emission spectrum predominantly between 500 nm and 578 nm and at least one additional laser source (11B, 1 IC), each additional laser source being configured to generate an additional light beam having an additional light power and an emission spectrum different from that of the main laser source (1 IA), said main laser source (1 IA) and said at least one additional laser source (1 IB, 1 IC) being selectively controllable and the light emission assembly (14) being configured to emit a total light power resulting from the sum of the main and additional light powers; - a brightness sensor (16) capable of measuring ambient brightness; - a control unit (15) configured to, when the measured ambient brightness is greater than a predetermined ambient brightness threshold, modify an initial total light power emitted by the light-emitting assembly (14) and formed by the sum of an initial main light power emitted by the main laser source (1 IA) and one or more initial additional light powers emitted by each of the additional laser sources (1 IB, 1 IC), into a final total light power emitted by the light-emitting assembly and formed by the sum of a final main light power emitted by the main laser source (1 IA) and one or more final additional light powers, emitted by each of the additional laser sources (11B, 1 IC),the final total light power being less than or equal to the initial total light power, the sum of the final additional light powers of the additional laser sources (1 IB, 1 IC) being less than the sum of the initial additional light powers of the additional laser sources (11B, 1 IC), and, the final main light power of the main laser source (1 IA) being greater than the initial main light power of said main laser source (1 IA).

2. Light device (1) according to the preceding claim, in which the light emission assembly (14) comprises several additional laser sources (11B, 11C) including a first additional laser source (11B) having an emission spectrum mainly between 620 nm and 700 nm and a second additional laser source (1 IC) having an emission spectrum mainly between 430 nm and 500 nm.

3. A lighting device (1) according to one of claims 1 or 2, wherein the lighting device (1) comprises an oscillating mirror (13) configured to oscillate between several positions and to reflect the main light beam emitted by the main laser source (1 IA) and the additional light beams emitted by the additional laser sources (1 IB, 1 IC) in order to form said image.

4. Method for controlling (2) a light device for a motor vehicle according to any one of claims 1 to 3, the control method (2) comprising the following steps: - a step of measuring (20) an ambient brightness by the ambient brightness sensor (16); - a step of comparing (21) the measured ambient brightness with a predetermined ambient brightness threshold; - if the measured ambient brightness is greater than the predetermined ambient brightness threshold, a step of modifying (25) the initial total light power emitted by the light emission assembly (14) and formed by the sum of an initial main light power emitted by the main laser source (1 IA) and one or more initial additional light powers emitted by each of the additional laser sources (11B, 1 IC),into a final total light power emitted by the light emitting assembly and formed by the sum of a final main light power emitted by the main laser source (1 IA) and one or more final additional light powers emitted by each of the additional laser sources (11B, 1 IC), the final total light power being less than or equal to the initial total light power, the sum of the final additional light powers of the additional laser sources (1 IB, 1 IC) being less than the sum of, initial additional light powers of the additional laser sources (11B, 11C), and the final main light power of the main laser source (1 IA) being greater than the initial main light power of said main laser source (1 IA).

5. A driving method (2) according to claim 4, wherein, during the step (25) of modifying the initial total light power into the final total light power, the final additional light power of each of the additional laser sources is less than the final main light power.

6. Control method (2) according to claim 5, wherein, during the step (25) of modifying the initial total light power into the final total light power, the sum of the final additional light powers is less than the final main light power.

7. Control method (2) according to one of claims 4 to 6, wherein during the step (25) of modifying the initial total light power into the final total light power, the additional laser sources (11B, 11C) are switched off.

8. Control method (2) according to one of claims 4 to 7, in which the predetermined ambient brightness threshold corresponds to a light power greater than or equal to one third of the initial total light power, and less than or equal to the initial total light power.

9. Motor vehicle (3) comprising: - a support for projecting an image, such as all or part of a dashboard and / or an interior panel of a passenger compartment of the motor vehicle, and in particular a side door trim panel or quarter panels, and - a lighting device (1) according to any one of claims 1 to 3, the lighting device (1) being configured to project the image onto the projection support.

10. Motor vehicle (3) according to the preceding claim, in which the control unit of the lighting device (1) is configured to implement the steps of the control method (2) according to one of claims 4 to 8.

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