Vehicle lighting module comprising an optical element, and method for dynamically controlling at least one parameter to control the angle of the field of vision of a light beam emitted by such a lighting module

Abstract

The invention relates to a vehicle light module (2), comprising a housing (4) defining a compartment (12) within which are arranged: at least one laser light source (14), an optical element (16) arranged opposite said at least one laser light source (14) and configured to generate a light beam (20) towards an optical output (5) of the housing (4), and a light source control device (18) connected to said at least one laser light source (14).According to the invention, the optical element (16) comprises a microelectromechanical system (22) and a control device (24) for the microelectromechanical system (22), the microelectromechanical system (22) being provided with a scanning mirror (25) arranged opposite said at least one laser light source (14), the control device (24) for the microelectromechanical system (22) being configured to perform dynamic control of at least one parameter for controlling an angle (26) of the field of view of projection of said light beam (20) according to at least two distinct operating modes. FIG. 1.

Description

Title of the invention: Vehicle lighting module comprising an optical element, and method for dynamically controlling at least one parameter for controlling the angle of the field of vision of a light beam emitted by such a lighting module. Technical field

[0001] The present invention relates to the field of lighting, particularly automotive lighting. The invention relates specifically to a vehicle lighting module comprising at least one laser light source and an optical element arranged opposite the laser light source and configured to generate a light beam towards an optical output of a housing in the lighting module. Without limiting the scope of the present invention, the lighting module may be mounted in a lighting or signaling element, and / or in a motor vehicle headlight. The present invention also finds applications in lighting modules intended for interior vehicle lighting (mounted, for example, in the vehicle's overhead console to provide interior lighting for a dashboard or glove compartment).

[0002] The invention also relates to a method of dynamically controlling at least one parameter for controlling an angle of the field of vision of projection of a light beam emitted by such a light module, as well as a use of such a light module. State of the art

[0003] In the field of automotive lighting, light modules mounted in a vehicle's headlight are generally known for projecting an image and / or lighting functions onto the vehicle's dashboard or glove compartment. This type of light module typically comprises a housing defining a compartment within which are arranged: at least one light source, an optical element arranged opposite said at least one light source and configured to generate a light beam towards an optical output of the housing, and a control device for said at least one light source. The light source or sources are typically laser light sources. The optical element is, for example, an assembly of lenses or an assembly of reflectors. This assembly either projects the light emanating from the laser light source directly to a finite distance or collimates this light.

[0004] However, a drawback of these light modules is that they only allow an image and / or light functions to be projected onto the vehicle's dashboard or glove compartment in a single operating mode, which generally corresponds to nighttime operation. This is because the optical element of the light module is optimized for a single field of vision. During the day, the contrast level is reduced, and the field of vision of the light module, which is optimized for nighttime operation with ambient lighting, is therefore no longer suitable for daytime operation. Description of the invention

[0005] The present invention improves the situation.

[0006] An objective of the invention is to provide a vehicle lighting module, allowing a beam of light to be projected onto a vehicle element or onto the ground according to at least two distinct operating modes corresponding to two different fields of vision, and allowing in particular to operate both at night and during the day.

[0007] To this end, a first aspect of the invention relates to a vehicle module, the light module comprising a housing defining a compartment inside which are arranged: at least one laser light source, an optical element arranged opposite said at least one laser light source and configured so as to generate a light beam towards an optical output of the housing, and a light source control device connected to said at least one laser light source.

[0008] According to the invention, the optical element comprises a microelectromechanical system and a control device for the microelectromechanical system, the microelectromechanical system being equipped with a scanning mirror, the scanning mirror being arranged opposite said at least one laser light source and being suitable for generating said light beam towards the optical output of the housing, the control device for the microelectromechanical system being configured to perform dynamic control of at least one parameter for controlling an angle of the field of view of projection of said light beam according to at least two distinct operating modes.

[0009] For the purposes of this invention, "microelectromechanical system" (MEMS) means any microsystem made from semiconductor materials and oscillating in two distinct directions, comprising one or more mechanical elements, and using electricity as an energy source, in order to perform a sensor or actuator function with at least one structure having millimeter dimensions; the function of the system being partly ensured by the shape of this structure.

[0010] Thanks to such a configuration of the optical element, which comprises a microelectromechanical system equipped with a scanning mirror and a control device for the microelectromechanical system, the light module according to the invention can project a beam of light onto a vehicle component or onto the ground in at least two distinct operating modes corresponding to two different fields of vision. This allows the field of vision of the optical element to be dynamically adapted according to ambient lighting conditions. Typically, in nighttime conditions, the projection field of vision of the light module is increased and the illuminance level reduced, while in daytime conditions, the projection field of vision of the light module is reduced (by reducing the oscillation angle of the scanning mirror) and the illuminance level increased so that the projected image and / or light features are clearly visible.To achieve this, the scanning mirror operates at maximum oscillation amplitude during the night, while during the day it operates at a reduced oscillation amplitude. This is because a microelectromechanical system operates with limited power (due to user eye safety and the maximum power level of the laser light source). Consequently, with the field of view of the light module used in nighttime conditions (i.e., without dynamic modification) and with the maximum power level of the laser light source, the beam projection area is invisible during the day. Using a microelectromechanical system equipped with a scanning mirror coupled to a microelectromechanical system control device allows for dynamic control of the mirror's oscillation angle, thus resolving this issue.

[0011] According to one embodiment of the invention, the control device of the microelectromechanical system is configured to perform dynamic control of an oscillation control voltage of the scanning mirror, for said control of the angle of the field of vision of projection of said light beam according to at least two distinct operating modes.

[0012] According to another embodiment of the invention, the control device of the microelectromechanical system is connected to the light source control device, the control device of the microelectromechanical system being configured to send to the light source control device instructions for switching the laser light source on and off in a manner synchronized with one or more scanning positions of the scanning mirror, for said control of the angle of the field of view of the projection of said light beam according to at least two distinct operating modes. This makes it possible to send more light to the center of the projection area of ​​the light beam than to the sides thereof (because the scanning speed of the scanning mirror is lower on the (sides rather than the center), and therefore to send more optical power to the center while still ensuring the user's eye safety. Indeed, the potential transit time of light in the user's eye is longer at the edges of the projection, thus increasing the risk of eye injury. A maximum level of optical flux must therefore be considered. This level is lower than at the center of the beam's projection area, where the transit time of light in the user's eye is shorter.

[0013] According to one embodiment of the invention, the light module further comprises an ambient light or light contrast sensor connected to the control device of the microelectromechanical system. This allows the parameter for controlling the angle of the projection field of the light beam to be automatically adjusted according to the level of ambient light or light contrast detected. The ambient light or light contrast sensor can, in particular, be arranged on the vehicle so as to detect a background haze of sky and / or sun.

[0014] According to one embodiment of the invention, the scanning mirror is a recurrent scanning mirror or a Lissajous figure scanning mirror.

[0015] Another object of the invention relates to a vehicle lighting and / or signaling element, in particular for a motor vehicle, comprising a light module according to the invention.

[0016] Here, "vehicle" means any type of vehicle such as a motor vehicle, a moped, a motorcycle, a warehouse storage robot, or any other machine capable of carrying at least one passenger or intended for the transport of persons or objects.

[0017] Another object of the invention relates to a vehicle projector comprising a light module or a lighting and / or signaling element according to the invention.

[0018] Another object of the invention relates to a method for dynamically controlling at least one parameter for controlling an angle of the field of vision of projection of a light beam emitted by a vehicle light module, the light module comprising a housing defining a compartment inside which are arranged: at least one laser light source, an optical element arranged opposite said at least one laser light source and configured so as to generate said light beam towards an optical output of the housing, and a light source control device connected to said at least one laser light source.

[0019] According to the invention, the optical element comprises a microelectromechanical system and a control device for the microelectromechanical system, the microelectromechanical system being equipped with a scanning mirror, the scanning mirror being arranged opposite said at least one laser light source and being adapted to generate said light beam towards the optical output of the housing, and the method is implemented by the control device of the microelectromechanical system and comprises a first phase during which the control of said at least one parameter is carried out according to a first mode of operation for a control of a first angle value of the field of vision of projection of the light beam; and a second phase during which the control of said at least one parameter is carried out according to a second mode of operation, distinct from the first mode of operation, for a control of a second angle value of the field of vision of projection of the light beam, the second angle value of the field of vision of projection being distinct from the first angle value.

[0020] According to one embodiment of the invention, the first phase consists of controlling a first oscillation control voltage of the scanning mirror, and the second phase consists of controlling a second oscillation control voltage of the scanning mirror, the second control voltage being distinct from the first control voltage.

[0021] According to another embodiment of the invention, the control device of the microelectromechanical system is connected to the light source control device, and the first phase consists of sending to the light source control device a first series of control instructions to turn on or off the laser light source in a manner synchronized with one or more scanning position(s) of the scanning mirror, and the second phase consists of sending to the light source control device a second series of control instructions to turn on or off the laser light source in a manner synchronized with one or more scanning position(s) of the scanning mirror, the second series of control instructions being distinct from the first series of control instructions.

[0022] According to one embodiment of the invention, the light module further comprises an ambient brightness or light contrast detector connected to the control device of the electromechanical microsystem, and the first phase of the method is implemented following a detection, by said detector, of a first level of ambient brightness or light contrast, and a sending to the control device of the electromechanical microsystem, by said detector, of a first corresponding detection signal, and the second phase of the method is implemented following a detection, by said detector, of a second level of ambient brightness or light contrast, distinct from the first level of ambient brightness or light contrast, and a sending to the control device of the electromechanical microsystem, by said detector, of a second corresponding detection signal, distinct from the first detection signal.

[0023] According to one embodiment of the invention, each of the first and second angle values ​​of the field of vision of the projected light beam is greater than a threshold angle value substantially equal to 4 degrees. Such a threshold angle value is a normative value corresponding to the minimum degree of perception of a human eye pupil, which more precisely corresponds to the angular dimension of a dilated pupil with a diameter of 7 mm at a distance of 100 mm. Before this distance, the eye cannot focus, and therefore the ocular risk does not need to be assessed.

[0024] Another object of the invention relates to the use of a light module according to the invention to perform a photometric function of lighting and / or signaling and / or interior lighting of a vehicle.

[0025] According to a preferred embodiment of the invention, the function is an interior lighting function for a dashboard or glove compartment of a vehicle. Brief description of the drawings

[0026] Other features and advantages of the invention will become apparent from an examination of the detailed description below, and the accompanying drawings in which:

[0027] [Fig-1] is a schematic representation of a light module according to a mode of realization of the invention;

[0028] [Fig.2] is a schematic representation of the light module of [Fig.1], in a first operating mode of the light module; and

[0029] [Fig.3] is a schematic representation of the light module of [Fig.1], in a second operating mode of the light module.

[0030] In this document, unless otherwise specified, the terms "horizontal," "vertical" or "transverse," "lower," "upper," "above," "below," "top," "bottom," and "side" are defined with respect to the orientation of the light module 2 according to the invention, intended to be mounted in a vehicle lighting and / or signaling element. In particular, in this application, the term "vertical" designates an orientation perpendicular to the horizon, while the term "horizontal" designates an orientation parallel to the horizon. Detailed description

[0031] Figures 1 to 3 represent a vehicle light module 2 according to the invention. The light module 2 is typically integrated into a vehicle lighting and / or signaling element or into a vehicle headlight, the latter elements not being shown in the figures for clarity. According to a preferred embodiment of the invention, the light module 2 is intended for interior vehicle lighting and is, for example, mounted in the overhead light in order to provide interior lighting for the dashboard or glove compartment of the vehicle.

[0032] The light module 2 includes a housing 4 preferably hermetically sealed and equipped with an optical output 5. Preferably, as illustrated in [Fig.1], the light module 2 also includes an ambient light or light contrast detector 6.

[0033] The housing 4 is conventionally closed by an optic (not shown in the figures), arranged at the optical output 5 of the housing 4. The optic is typically a transparent protective window. The housing 4 defines a compartment 12 within which are arranged at least one laser light source 14, an optical element 16, and a light source control device 18.

[0034] In the particular embodiment illustrated in [Fig.1], the light module 2 comprises a single laser light source 14. In an alternative not shown, the light module 2 may, for example, comprise three laser light sources: a first red laser light source, a second green laser light source and a third blue laser light source, whose light beams are combined into a single collimated laser beam.

[0035] The optical element 16 is arranged opposite the laser light source 14 and configured to generate a light beam 20 towards the optical output 5 of the housing 4. The optical element 16 comprises an electromechanical microsystem 22 and a control device 24 for the electromechanical microsystem 22. Preferably, as illustrated in [Fig. 1], the control device 24 for the electromechanical microsystem 22 is connected to the light source control device 18. The control device 24 for the electromechanical microsystem 22 is also connected to the ambient light or light contrast detector 6.

[0036] The electromechanical microsystem 22 is equipped with a scanning mirror 25 arranged opposite the laser light source 14 and is adapted to generate the light beam 20 towards the optical output 5 of the housing 4. The scanning mirror 25 oscillates at a predetermined frequency, such a frequency being, for example, substantially equal to 20 kHz, although this value is not limiting within the scope of the present invention. The scanning mirror 25 is, for example, a recurrent scanning mirror (also called a raster scan mirror), or a Lissajous scan mirror, although this is not limiting within the scope of the present invention. A recurrent scanning mirror oscillates about a single axis and descends about another axis at a relatively moderate speed. A Lissajous scan mirror oscillates about two axes.The scanning speed of the scanning mirror 25 is chosen to allow retinal persistence of the projected image for a human eye.

[0037] The control device 24 of the electromechanical microsystem 22 is configured to perform dynamic control of at least one parameter for controlling an angle 26 of the field of vision of the projection of the light beam 20 according to at least two distinct operating modes. Angle 26 is a solid angle. More specifically, according to a first embodiment of the invention, the control device 24 for the electromechanical microsystem 22 is configured to perform dynamic control of an oscillation control voltage for the scanning mirror 25, for controlling angle 26 of the projection field of view of the light beam 20 in at least two distinct operating modes. The dynamic control of the oscillation control voltage of the scanning mirror 25 allows control, by the control device 24, of the amplitude of the scan performed by the scanning mirror 25. According to this first embodiment of the invention, the parameter dynamically controlled for controlling angle 26 of the projection field of view of the light beam 20 is therefore the oscillation control voltage of the scanning mirror 25.

[0038] According to a second embodiment of the invention, distinct from the first embodiment and illustrated in [Fig. 1] (in which the control device 24 of the electromechanical microsystem 22 is connected to the light source control device 18), the control device 24 is configured to send to the light source control device 18 instructions to switch on and off the laser light source 14 in a manner synchronized with one or more scanning position(s) of the scanning mirror 25, for controlling the angle 26 of the field of vision of projection of the light beam 20 according to at least two distinct operating modes.More specifically, the laser light source 14 is controlled to switch off when the scanning mirror 25 reaches the edges of the scanning area. This overcomes the limitations imposed by user eye safety and allows for an increase in luminance and illuminance level (optical power) when the scanning mirror 25 reaches the center of the scanning area. According to this second embodiment of the invention, the dynamically controlled parameters for controlling the angle 26 of the projection field of the light beam 20 are therefore the switching on and off of the laser light source 14, synchronized with the scanning position(s) of the scanning mirror 25.

[0039] The light source control device 18 is connected to the laser light source 14.

[0040] The method for dynamically controlling at least one parameter for controlling the angle 26 of the field of vision of the projection of the light beam 20 according to the invention will now be described with reference to Figures 2 and 3. The method is implemented by the control device 24 of the electromechanical microsystem 22.

[0041] The method comprises a first phase, illustrated for example in [Fig. 2], during which the parameter control is carried out according to a first mode operating procedure for controlling a first angle value of the projection field of view of the light beam 20. When the light module 2 includes an ambient light or light contrast sensor 6, as in the illustrative example in [Fig. 1], the first phase of the method may be preceded by a detection step, by the ambient light or light contrast sensor 6, of a first level of ambient light or light contrast, and by a step of sending a corresponding first detection signal to the control device 24 of the electromechanical microsystem 22, via the sensor 6. The control device 24 of the light module 2 then has a conversion table between ambient light or light contrast levels on the one hand, and angle values ​​of the projection field of view of the light beam 20 on the other.

[0042] According to the first embodiment of the invention, the first phase of the process consists of a control, by the control device 24, of a first oscillation control voltage of the scanning mirror 25. According to the second embodiment of the invention, the first phase of the process consists of a sending to the light source control device 18, by the control device 24, of a first series of instructions to switch on or off the laser light source 14 in a manner synchronized with one or more scanning position(s) of the scanning mirror 25.

[0043] The method then comprises a second phase, which follows the first phase and is illustrated for example in [Fig. 3], during which the parameter control is carried out according to a second operating mode, distinct from the first operating mode, for a control of a second angle value of the projection field of vision of the light beam 20. The second value of the angle 26 of the projection field of vision is distinct from the first angle value. When the light module 2 includes an ambient light or light contrast detector 6, as is the case in the illustrative example of [Fig. 3], the parameter control is carried out according to a second operating mode, distinct from the first operating mode, for a control of a second angle value of the projection field of vision of the light beam 20. The second angle value 26 of the projection field of vision is distinct from the first angle value. When the light module 2 includes an ambient light or light contrast detector 6, as is the case in the illustrative example of [Fig. 3], the parameter control is carried out according to a second operating mode, distinct from the first operating mode, for a control of a second angle value of the projection field of vision of the light beam 20.[l], the second phase of the process may be preceded by a detection step, by the ambient brightness or light contrast detector 6, of a second level of ambient brightness or light contrast, distinct from the first level of ambient brightness or light contrast, and by a sending step to the control device 24 of the electromechanical microsystem 22, by the detector 6, of a second corresponding detection signal, distinct from the first detection signal.

[0044] According to the first embodiment of the invention, the second phase of the method consists of controlling, by the control device 24, a second oscillation control voltage of the scanning mirror 25. The second control voltage is separate from the first control voltage. According to the second embodiment of the invention, the second phase of the method consists of sending to the light source control device 18, by the control device 24, a second series of control instructions to turn on or off the laser light source 14 in a manner synchronized with one or more scanning position(s) of the scanning mirror 25. The second series of control instructions is distinct from the first series of control instructions.

[0045] Preferably, each of the first and second angle values ​​of the projection field of view of the light beam 20 is greater than a threshold angle value substantially equal to 4 degrees. In the particular embodiment shown in Figures 2 and 3, the second angle value 26 of the projection field of view of the light beam 20 is less than the first angle value 26 of the projection field of view of the light beam 20, and corresponds, for example, to daytime operation ([Fig. 3]). The first angle value 26 of the projection field of view of the light beam 20 corresponds to nighttime operation ([Fig. 2]). Typical numerical values ​​for these examples in Figures 2 and 3 could, for example, be: for [Fig.[Fig. 2] (night conditions), a first value of angle 26 of 40° x 20°, for a projection area SI of 36cm x 18cm, a luminous flux of 40 lumens and a first illuminance level of 620 lux; for [Fig. 3] (day conditions), a second value of angle 26 of 40° x 4°, for a projection area S2 of 36cm x 3.5cm, a luminous flux of 40 lumens and a second illuminance level of 3200 lux.

[0046] The first and second phases of the process are then implemented alternately as needed.

[0047] The present invention is not limited to the embodiments described above by way of example and extends to other variations. In particular, although the present invention has been described with reference to a light module 2 configured to operate in two distinct modes of operation, it applies equally to any light module configured to operate in three or more modes of operation.

Claims

Demands

1. Vehicle light module (2), the light module (2) comprising a housing (4) defining a housing (12) within which are arranged: at least one laser light source (14), an optical element (16) arranged opposite said at least one laser light source (14) and configured to generate a light beam (20) towards an optical output (5) of the housing (4), and a light source control device (18) connected to said at least one laser light source (14);characterized in that the optical element (16) comprises a microelectromechanical system (22) and a control device (24) for the microelectromechanical system (22), the microelectromechanical system (22) being equipped with a scanning mirror (25), the scanning mirror (25) being arranged opposite said at least one laser light source (14) and being adapted to generate said light beam (20) towards the optical output (5) of the housing (4), the control device (24) for the microelectromechanical system (22) being configured to perform dynamic control of at least one parameter for controlling an angle (26) of the field of vision of projection of said light beam (20) according to at least two distinct operating modes.;

2. Light module (2) according to claim 1, wherein the control device (24) of the microelectromechanical system (22) is configured to perform dynamic control of an oscillation control voltage of the scanning mirror (25), for said control of the angle (26) of the field of vision of projection of said light beam (20) according to at least two distinct modes of operation.

3. A light module (2) according to claim 1, wherein the control device (24) for the microelectromechanical system (22) is connected to the light source control device (18), the control device (24) for the microelectromechanical system (22) being configured to send to the light source control device (18) instructions for switching on and off the laser light source (14) in a manner synchronized with one or more scanning positions of the scanning mirror (25), for said control of the angle (26) of the field of view of projection of said light beam (20) according to at least two distinct operating modes.

4. Light module (2) according to any one of claims 1 to 3, wherein the light module (2) further comprises an ambient light or light contrast detector (6) connected to the control device (24) of the microelectromechanical system (22).

5. Light module (2) according to any one of claims 1 to 4, wherein the scanning mirror (25) is a recurrent scanning mirror or a Lissajous figure scanning mirror.

6. Vehicle lighting and / or signaling element comprising a light module (2) according to any one of the preceding claims.

7. Vehicle projector comprising a light module (2) according to any one of claims 1 to 5 or a lighting and / or signaling element according to claim 6.

8. Method for dynamically controlling at least one parameter for controlling an angle (26) of the field of vision of projection of a light beam (20) emitted by a vehicle light module (2), the light module (2) comprising a housing (4) defining a housing (12) within which are arranged: at least one laser light source (14), an optical element (16) arranged opposite said at least one laser light source (14) and configured to generate said light beam (20) towards an optical output (5) of the housing (4), and a light source control device (18) connected to said at least one laser light source (14);characterized in that the optical element (16) comprises a microelectromechanical system (22) and a control device (24) for the microelectromechanical system (22), the microelectromechanical system (22) being equipped with a scanning mirror (25), the scanning mirror (25) being arranged opposite said at least one laser light source (14) and being suitable for generating said light beam (20) towards the optical output (5) of the housing (4), and in that the method is implemented by the control device (24) for the microelectromechanical system (22) and comprises a first phase during which the control of said at least one parameter is carried out according to a first mode of operation; for a control of a first angle value of the field of vision of projection of the light beam (20); and a second phase during which the control of said at least one parameter is carried out according to a second mode of operation, distinct from the first mode of operation, for a control of a second angle value of the field of vision of projection of the light beam (20), the second angle value of the field of vision of projection being distinct from the first angle value.

9. A method according to claim 8, wherein the first phase consists of controlling a first oscillation control voltage of the scanning mirror (25), and the second phase consists of controlling a second oscillation control voltage of the scanning mirror (25), the second control voltage being distinct from the first control voltage.

10. A method according to claim 8, wherein the control device (24) of the microelectromechanical system (22) is connected to the light source control device (18), and wherein the first phase consists of sending to the light source control device (18) a first series of control instructions to turn on or off the laser light source (14) in a manner synchronized with one or more scanning position(s) of the scanning mirror (25), and the second phase consists of sending to the light source control device (18) a second series of control instructions to turn on or off the laser light source (14) in a manner synchronized with one or more scanning position(s) of the scanning mirror (25), the second series of control instructions being distinct from the first series of control instructions.

11. A method according to any one of claims 8 to 10, wherein the light module (2) further comprises an ambient light or light contrast sensor (6) connected to the control device (24) of the microelectromechanical system (22), and wherein the first phase of the method is carried out following detection, by said sensor (6), of a first level of ambient light or light contrast, and transmission to the control device (24) of the microelectromechanical system (22), by said sensor (6), of a first corresponding detection signal, and wherein the second phase of the method is carried out following a detection, by said detector (6), of a second level of ambient brightness or light contrast, distinct from the first level of ambient brightness or light contrast, and to a sending to the control device (24) of the microelectromechanical system (22), by said detector (6), of a second corresponding detection signal, distinct from the first detection signal.

12. A method according to any one of claims 8 to 11, wherein each of said first and second angle values ​​of the field of vision of projection of the light beam is greater than a threshold angle value substantially equal to 4 degrees.

13. Use of a light module (1; 12) according to any one of claims 1 to 5 to perform a photometric function of lighting and / or signaling and / or interior lighting of a vehicle.

14. Use of a light module (1; 12) according to claim 13, wherein the function is an interior lighting function for a dashboard or glove box of a vehicle.

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