Protection unit and detection assembly for a motor vehicle

Abstract

The invention relates to a protection unit (1) for an apparatus (21) and to a detection assembly (2) associating the apparatus (21) emitting or capturing radiation (23) through a region of interest of an optical surface (10) of the protection unit (1). The protection unit (1) further comprises at least one wave transducer (13) configured to generate an acoustic wave on or in the optical surface (10) in order to clean the optical region of interest (12). According to the invention, the protection unit (1) further comprises an openwork surface (30) located facing the optical surface (10), the openwork surface (30) comprising a solid portion (31) and at least one opening (32) through which the radiation (23) emitted and / or captured by the apparatus (21) can pass.

Description

protection unit and detection assembly for motor vehicle

[0001] The technical context of the present invention is that of sensors and in particular devices for cleaning an optical surface through which said sensors carry out their measurements. More particularly, the invention relates to a protection unit making it possible to carry out such cleaning, to a detection assembly comprising such a protection unit and to a motor vehicle.

[0002] In general, the present invention relates to a protection unit implementing a wave transducer for cleaning bodies in contact with the optical surface, by means of ultrasonic waves. By "cleaning", it is understood here that the wave transducer is configured to remove the bodies which were present in contact with the optical surface so that, following the cleaning operation, the optical surface is free of said bodies.

[0003] The present invention finds applications in many fields. By way of non-limiting example, one objective sought by the present invention is to overcome the effects linked to the accumulation of bodies on an optical surface, such as in particular drops of rain, frost or snow.

[0004] In order to rid a surface of these bodies, when they are in the liquid state and present in the form of drops on the optical surface, it is known to rotate said drops in order to be able to evacuate them from the surface. A known disadvantage of this technique lies in the fact that it is not suitable for surfaces whose area is greater than a few square centimeters.

[0005] We also know the implementation of an electric field to control the hydrophobicity of a surface, as described for example in KR 2018 0086173 A1. This technique, known by the acronym EWOD meaning "Electro Wetting On Devices" in English and translatable as "Electrowetting device on dielectric", consists of applying a potential difference between two electrodes, so as to electrically polarize the surface from which we wish to make the liquid drops disappear and with the aim of modifying its wetting properties. By controlling the location of the polarization, the drop can then be moved.A known disadvantage of this technique is that it can only be implemented with specific materials and requires particularly precise positioning of the electrodes over the entire surface where we want to control the wetting properties, making its industrialization, mass production and integration into products intended for the automotive industry, for example, complex and even expensive.

[0006] Furthermore, we are also familiar with the use of a windshield wiper on a motor vehicle windshield. This proven technique, however, has the disadvantage of disrupting the driver's field of vision. In addition, successive wiper strokes spread the greasy particles deposited on the surface of the windshield. In addition, it is necessary to regularly renew the wiper pads, which wear out during use. Finally, this technique is not, or is difficult to use, for cleaning sensors used on motor vehicles, such as lidars, proximity sensors, or cameras.

[0007] For cleaning windshields or sensors used on motor vehicles, such as, for example, lidars, proximity sensors or cameras, cleaning methods are finally known for removing liquid accumulating on an optical surface of the sensor via generation and propagation of ultrasonic waves in or on the optical surface. In particular, document WO 2012 / 095643 A1 is known, which describes a method for removing raindrops by ultrasonic vaporization. The amplitude and frequency of vibration are chosen so that the raindrops falling on the windshield are vaporized as soon as they enter a vibratory zone of the windshield surface.However, in order to obtain vaporization of a drop of liquid, a puddle or a film, the powers required to set the vibrating zone into vibration are high, which limits their practical implementation, particularly for the development of autonomous devices. It is also well known that vaporization requires energies greater than those required to move drops on a support.

[0008] The techniques presented above all have disadvantages linked to their integration on more compact surfaces or located near small surfaces, or located behind openwork surfaces and making both their access and their cleaning more difficult.

[0009] The object of the present invention is to provide a novel protection unit in order to address at least largely the above problems and to further lead to other advantages.

[0010] Another object of the invention is to facilitate the cleaning of an optical surface located behind an openwork surface.

[0011] Another object of the invention is to enable such cleaning while camouflaging the wave transducer and making it less visible.

[0012] According to a first aspect of the invention, at least one of the aforementioned objectives is achieved with a unit for protecting an optical surface intended to be associated with an apparatus configured to capture and / or emit radiation through a region of optical interest of the optical surface, the protection unit comprising:

[0013] - the optical surface;

[0014] - an openwork surface integral with the optical surface and placed opposite said optical surface, the openwork surface comprising a solid part and at least one opening made in the solid part;

[0015] - at least one wave transducer mechanically coupled to the optical surface and configured to generate a wave propagating through the optical surface and towards and / or in the region of optical interest, the waves generated by the at least one wave transducer are of the ultrasonic wave type.

[0016] In the context of the present invention, the protection unit makes it possible to protect a device intended to be located behind the optical surface in order to prevent dust, raindrops or any particle from reaching the device and hindering its proper functioning. In the context of the invention, the protection unit can be implemented with any device of a motor vehicle, and take any form.

[0017] In the context of the present invention, the openwork surface is a mechanical part placed in front of the optical surface, relative to a mean direction of propagation of the waves emitted and / or received by the device with which the protection unit is intended to collaborate. The openwork surface may be formed of one or more parts. The openwork surface is integral with the protection unit, so that there is no mobility between the openwork surface and the optical surface. By way of non-limiting examples, the openwork surface may be a grille, a radiator grille, a sheet metal part having at least one opening, a bumper part having at least one opening. According to a particularly advantageous embodiment, the openwork surface comprises a logo of the motor vehicle on which the protection unit according to the first aspect of the invention is intended to be mounted.

[0018] In the context of the present invention, the logo takes the form of a punch or a badge whose shapes and dimensions are representative of a motor vehicle brand or a motor vehicle model. In the context of the invention, the logo is preferably of the type of a logo embedded on a front face of a motor vehicle, and in particular at the level of a grille of the front face.

[0019] Thus, the protection unit according to the first aspect of the invention makes it possible to optimally combine the logo of a motor vehicle and the presence of devices located behind said logo, the protection unit thus making it possible to propose a particularly advantageous configuration for the at least one wave transducer in order to allow optimal operation.

[0020] In the context of the present invention, the solid parts of the openwork surface form opaque parts in particular to the radiation emitted and / or captured by the device intended to be located behind. The solid parts are for example parts formed of material, while the at least one opening of the openwork surface forms a part free of material.

[0021] By way of non-limiting example, the openwork surface may be formed from any material, and in particular from a metallic or plastic material.

[0022] In the context of the present invention, the at least one wave transducer is of the type of an electronic chip configured to be able to generate the waves in question. By way of non-limiting example, the at least one wave transducer is of the type of an electromechanical comb whose electrical polarization makes it possible to generate the waves, so that they propagate in or on the optical surface, in the direction of and / or in the region of optical interest.

[0023] The waves generated by the at least one wave transducer advantageously have a fundamental frequency of between 0.1 MHz and 1000 MHz, preferably between 15 MHz and 30 MHz, for example equal to 20 MHz. Additionally or alternatively, the waves generated by the at least one wave transducer advantageously have a surface amplitude – or deformation amplitude – of between 1 nanometer and 500 nanometers.

[0024] In the context of the present invention, the waves generated by the at least one wave transducer are of the ultrasonic wave type. More particularly, the waves thus generated are of the type:

[0025] – an ultrasonic surface wave, i.e. of the Rayleigh wave type, when the optical surface has a thickness greater than the wavelength of the ultrasonic surface wave. Such a surface wave propagates on the surface of the optical surface. A Rayleigh wave is preferred because a maximum proportion of the wave energy is concentrated on the face of the optical surface on which it propagates, and can be transmitted to a body, for example a raindrop, resting on the optical surface. In this case, the surface wave propagates on the optical surface with which the at least one transducer is acoustically coupled, or even preferentially on which it is fixed;

[0026] – of an ultrasonic core wave – or Lamb wave, when the optical surface has a thickness less than the wavelength of the ultrasonic core wave. Such a core wave propagates through the optical surface and makes it possible to “vibrate” the entire optical surface thus crossed by the core wave, that is to say the two optical faces located opposite each other and forming the optical surface.

[0027] Thus, the protection unit according to the invention makes it possible to effectively clean the optical surface by means of wave propagation in said optical surface, such that a body, such as for example a raindrop, in contact with the optical surface, is set in motion by the wave generated by each at least one wave transducer, with or without the aid of an external force, such as for example gravity or an aerodynamic force.

[0028] In the context of the present invention, the optical surface may be of any type and fulfill any function with respect to one or more devices intended to emit or capture radiation passing through said optical surface and placed opposite said optical surface. By way of non-limiting example, the optical surface may be an optical lens making up the device(s) through which the radiation passes or a protective surface positioned opposite the optical lens(es) of the device(s). Generally speaking, the optical surface is formed of a material which allows the propagation of ultrasonic waves emitted by the wave transducer, whether they are surface or core waves. By way of non-limiting example, and according to a preferred embodiment of the invention, the optical surface is formed of glass in order to promote the propagation of such waves.Additionally, the optical surface, or at least the region of optical interest, is formed from a material transparent to the radiation emitted or captured by the device intended to be associated with the protection unit according to the first aspect of the invention. In particular, the radiation emitted or captured by the device propagates in the optical surface, or at least in its region of optical interest, by transmission and / or refraction and / or diffusion, so that a majority of the radiation arriving from a first side of the optical surface – or at least its region of optical interest – emerges from the other side of the optical surface, at a second side of the optical surface – or at least its region of optical interest.

[0029] In the context of the present invention, the region of optical interest corresponds to a part of the optical surface located opposite the apparatus intended to be associated with the protection unit and said optical surface. The region of optical interest corresponds to the part of the optical surface at which the radiation emitted or captured by the apparatus passes through the optical surface.

[0030] In the context of the present invention, the apparatus intended to be associated with the optical surface of the protection unit is configured to capture and / or emit radiation. For this purpose, it comprises a sensor and / or an emitter of the radiation. The radiation is for example of the type of electromagnetic radiation, a spectrum of which has wavelengths which may be located in the visible and / or invisible spectrum. By way of non-limiting example, the apparatus is preferably chosen from an optical remote sensing apparatus, such as for example a lidar, a photographic apparatus, a camera, a radar, an infrared sensor and an ultrasonic rangefinder.

[0031] In particular, in the context of the present invention, the integration of such a device behind the logo is particularly cramped and narrow. Furthermore, the presence of the at least one opening in the openwork surface tends to cause an accumulation of particles at the optical surface located opposite said at least one opening, subsequently making the operation of the device intended to be located behind more difficult and less optimal.

[0032] Thus, the protection unit in accordance with the first aspect of the invention makes it possible to facilitate the proper functioning of the apparatus with which it is intended to be associated, since the region of optical interest of the optical surface through which the radiation captured or emitted by said apparatus is cleaned by the wave transducer. This advantageous configuration thus makes it possible to reduce interference between bodies which would have been present on the optical surface, at the level of the optical regions of interest, and the radiation passing through said optical regions of interest.

[0033] The protection unit in accordance with the first aspect of the invention advantageously comprises at least one of the improvements below, the technical characteristics forming these improvements being able to be taken alone or in combination:

[0034] - the at least one wave transducer is located opposite the solid part of the openwork surface. This advantageous configuration makes it possible to mask the at least one wave transducer behind the solid part of the openwork surface. It also makes it possible to avoid cluttering parts of the optical surface located opposite the at least one opening of the openwork surface, preferably reserved for future alignment with the device with which the protection unit is intended to collaborate. More particularly, the alignment between the at least one wave transducer and the solid part of the openwork surface is observed relative to an axis perpendicular to the optical surface located opposite;

[0035] – the at least one wave transducer is fixed securely to the optical surface by any means, and in particular by gluing;

[0036] - the at least one wave transducer is intended to be electrically connected to an electrical device via at least one electrical wire connected to the at least one wave transducer, the at least one electrical wire extending opposite the solid part. The electrical device to which the at least one wave transducer is intended to be electrically connected is for example of the type of an electrical energy source or of a control unit of the at least one transducer. Thus, in the context of the present invention, the at least one electrical wire connecting the at least one wave transducer to the electrical device is of the type of an electrical power supply wire used to polarize the at least one wave transducer and / or a control wire transmitting an electrical signal used to control an operation of the at least one wave transducer. The at least one electrical wire preferably extends along and against the optical surface.In the context of the invention, the at least one electrical wire always extends – for its part located opposite the openwork surface – opposite the solid part of the openwork surface in order to prevent said at least one electrical wire from being made visible. More particularly, the alignment between the at least one electrical wire and the solid part of the openwork surface is observed relative to an axis perpendicular to the optical surface located opposite;

[0037] - in the context of the invention, the at least one electric wire may be of the type of an electric cable comprising one or more electric wires braided together and / or arranged inside an insulating sheath. Alternatively, each at least one electric wire may comprise a conductive element housed in an insulating sheath;

[0038] - the at least one electrical wire is securely attached to the optical surface. This advantageous configuration makes it possible to prevent the at least one electrical wire from moving during use of the protection unit according to the first aspect of the invention, or even from breaking or being damaged during this use. In the context of the present invention, the at least one electrical wire may be securely attached to the optical surface by any means;

[0039] – preferably, the at least one electrical wire is bonded to the optical surface. In the context of the invention, the at least one electrical wire may be bonded to the optical surface along the entire length of said at least one electrical wire. Alternatively, the at least one electrical wire may be bonded to the optical surface in a non-continuous manner, or even only at its terminations;

[0040] – according to a first embodiment, the at least one wave transducer is located on the side of a first face of the optical surface – called the inner face – intended to be located on the side of the device with which the protection unit is intended to collaborate, opposite a second face of said optical surface – called the outer face – located opposite the openwork surface, the waves generated by the at least one wave transducer being of the core wave type. In other words, the at least one device and the at least one wave transducers are located on the same side of the optical surface, relative to a direction of propagation of the radiation emitted by the at least one device. This advantageous configuration thus makes it possible to place the at least one transducer on the side of the at least one device, depending on the available space.Also, the at least one wave transducer is advantageously configured to generate core or Lamb waves in the direction of and / or in the region of optical interest and through the optical surface, in order to reach the face of the optical surface which is subjected to the projection of raindrops and / or particles and which therefore needs to be cleaned, on the side of the openwork surface;

[0041] – in the first embodiment, a wavelength of the wave generated by the at least one wave transducer is greater than or equal to twice a thickness of the optical surface taken at the level of the optical region of interest. This advantageous configuration makes it possible to better dimension both the thickness of the optical surface and the wavelength of the waves generated by the at least one transducer, for optimal operation and optimal cleaning of the optical surface located opposite the openwork surface;

[0042] – according to a second embodiment, the at least one wave transducer is located on the side of an outer face of the optical surface, located opposite the openwork surface, the waves generated by the at least one wave transducer being of the Rayleigh wave type. In other words, the apparatus and the at least one wave transducer are located on either side of the optical surface, relative to a direction of propagation of the radiation emitted by the at least one apparatus. This advantageous configuration thus makes it possible to place the at least one transducer on the side of the optical surface subjected to the projection of raindrops and / or particles and which therefore needs to be cleaned. Thus, in this first configuration, the at least one wave transducer is advantageously configured to generate surface waves in the direction of and / or in the region of optical interest;

[0043] – in this second embodiment, a wavelength of the wave generated by the at least one wave transducer is less than or equal to one fifth of a thickness of the optical surface taken at the level of the optical region of interest. This advantageous configuration makes it possible to better dimension both the thickness of the optical surface and the wavelength of the waves generated by the at least one transducer, for optimal operation and optimal cleaning of the optical surface located opposite the openwork surface;

[0044] - the protection unit comprises a non-zero clearance between the optical surface and the openwork surface, so that the at least one wave transducer is not mechanically coupled with the openwork surface. In other words, the openwork surface is located at a distance from the at least one wave transducer, in order to allow mechanical decoupling between the at least one wave transducer and the openwork surface. This configuration thus makes it possible to avoid any interference between the at least one transducer and the openwork surface, and to promote the propagation of the waves generated by the at least one wave transducer in the optical surface;

[0045] - a dimension of the clearance, taken in a direction perpendicular to the optical surface, is greater than 100 µm;

[0046] – advantageously, the protection unit comprises a cover covering the at least one wave transducer. The cover thus prevents water and / or bodies from infiltrating into the at least one wave transducer, which would then lead to premature and undesirable malfunction. The cover is fixedly attached to the at least one wave transducer or fixedly attached to the optical surface;

[0047] - the optical surface and the openwork surface are integral with each other. In other words, the optical surface and the openwork surface are held immobile relative to each other;

[0048] - according to a first embodiment variant, the openwork surface is fixedly attached to a support by means of fixing lugs which extend through slots provided in the optical surface. In the context of the invention, the optical surface is located in an intermediate position between the support and the openwork surface, relative to a mean direction of propagation of the radiation emitted and / or captured by the device intended to collaborate with the protection unit. In other words, the support is located on the side of a first face of the optical surface – called the inner face – located on the side of the device with which the protection unit is intended to collaborate, and the openwork surface is then located at a second face of said optical surface – called the outer face – located opposite the openwork surface and opposite the inner face.In other words, the support and the openwork surface are located on either side of the optical surface, relative to a direction of propagation of the radiation emitted by the at least one device;

[0049] – according to a second embodiment variant, the openwork surface is fixed integrally to the optical surface by means of fixing lugs integral with the optical surface. In this embodiment variant, the openwork surface is linked directly to the optical surface, without passing through an intermediate part forming the support in the first embodiment variant described previously;

[0050] - in either of the embodiments, the fixing lugs can take any shape and are configured to allow mechanical coupling with the support or the optical surface to which they are connected;

[0051] - in either of the embodiments, the at least one wave transducer is placed in an intermediate position between the fixing lugs and the region of optical interest. In other words, in a plane formed by the optical surface, the at least one transducer is located between, on the one hand, an area of ​​the optical surface at which the fixing lugs pass or are fixed, and, on the other hand, the region of optical interest. Thus, the waves generated by the at least one wave transducer directly reach the region of optical interest without passing through the area of ​​the optical surface in which the fixing lugs are located. This advantageous configuration makes it possible to guarantee better operation of the at least one wave transducer and, ultimately, better cleaning of the optical surface taken at the region of optical interest.

[0052] According to a second aspect of the invention, a detection assembly is proposed comprising:

[0053] - a protection unit in accordance with the first aspect of the invention or according to any of its improvements;

[0054] - at least one device configured to capture and / or emit radiation through the region of optical interest of the optical surface and through the at least one opening of the openwork surface.

[0055] In the context of the present invention, the at least one device is located opposite the optical surface, at a distance or against the optical surface, so that the radiation emitted or captured by said at least one device passes through the optical region of interest of the optical surface. Thus, the optical surface of the protection unit forms a protection surface for the at least one device.

[0056] Furthermore, in the context of the present invention, the at least one device is located opposite the at least one opening of the perforated surface, so as to allow the passage of the radiation emitted and / or captured by said at least one device through said at least one opening.

[0057] The detection assembly in accordance with the second aspect of the invention advantageously comprises at least one of the improvements below, the technical characteristics forming these improvements being able to be taken alone or in combination:

[0058] - the at least one device is integral with the optical surface. In this embodiment variant, the at least one device and the optical surface are made immobile relative to each other. According to a first embodiment variant, the at least one device is fixed integrally and directly to the optical surface, the at least one device comprising a fixing member collaborating with the optical surface. By way of non-limiting example, the optical surface can be glued to a front part of the at least one device, or the at least one device can be screwed or snapped onto the optical surface. According to a second embodiment variant, the at least one device is fixed integrally to a support to which the optical surface is also fixed integrally. In this second embodiment variant, the optical surface and the at least one device comprise fixing members collaborating with the support, such as for example fixing screws or fixing clips;

[0059] - according to a first embodiment, the at least one wave transducer is located on a first side of the optical surface opposite a second side at which the at least one device is located. In other words, the at least one device and the at least one wave transducers are located on either side of the optical surface, relative to a direction of propagation of the radiation emitted by the at least one device. This advantageous configuration thus makes it possible to place the at least one transducer on the side of the optical surface subjected to the projection of raindrops and / or particles and which therefore needs to be cleaned. Thus, in this first configuration, the at least one wave transducer is advantageously configured to generate surface waves in the direction of and / or in the region of optical interest;

[0060] - according to a second embodiment, the at least one transducer and the at least one device are located on the same side of the optical surface. In other words, the at least one device and the at least one wave transducers are located on the same side of the optical surface, relative to a direction of propagation of the radiation emitted by the at least one device. This advantageous configuration thus makes it possible to place the at least one transducer on the side of the at least one device, depending on the available space. Also, in this second configuration, the at least one wave transducer is advantageously configured to generate core waves in the direction of and / or in the region of optical interest and through the optical surface, in order to reach the face of the optical surface which is subjected to the projection of raindrops and / or particles and which therefore needs to be cleaned.

[0061] According to a third aspect of the invention, there is provided a motor vehicle comprising a detection assembly in accordance with the second aspect of the invention or according to any of its improvements.

[0062] Various embodiments of the invention are provided, incorporating, in all their possible combinations, the various optional features set out herein.

[0063] Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several examples of embodiment given for informational and non-limiting purposes with reference to the attached schematic drawings on the other hand, in which:

[0064] illustrates a schematic electrical profile view of a first exemplary embodiment of a detection assembly according to the second aspect of the invention and comprising a protection unit according to the first aspect of the invention;

[0065] illustrates a schematic electrical profile view of a second exemplary embodiment of a detection assembly according to the second aspect of the invention and comprising a protection unit according to the first aspect of the invention;

[0066] illustrates a schematic electrical front view of a third exemplary embodiment of a detection assembly according to the second aspect of the invention and comprising a protection unit according to the first aspect of the invention;

[0067] illustrates a schematic electrical front view of a fourth exemplary embodiment of a detection assembly according to the second aspect of the invention and comprising a protection unit according to the first aspect of the invention.

[0068] 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.

[0069] In particular, all the variants and embodiments described can be combined with each other if there is no technical obstacle to this combination.

[0070] In the figures, elements common to several figures retain the same reference.

[0071] With reference to FIGURES 1 to 4, the invention relates to a protection unit 1 of an optical surface 10 intended to be associated with an apparatus 21 configured to capture and / or emit radiation 23 through a region of optical interest 12 of the optical surface 10, the protection unit 1 comprising:

[0072] - the optical surface 10;

[0073] - an openwork surface 30 integral with the optical surface 10 and placed opposite said optical surface 10, the openwork surface 30 comprising a solid part 31 and at least one opening 32 formed in the solid part 31;

[0074] - at least one W wave transducer 13 mechanically coupled to the optical surface 10 and configured to generate a W wave propagating through the optical surface 10 and towards and / or in the optical region of interest 12.

[0075] The openwork surface 30 is a mechanical part placed in front of the optical surface 10, relative to a mean direction of propagation of the waves W emitted and / or received by the device 21 with which the protection unit 1 is intended to collaborate. The openwork surface 30 can be formed of one or more parts. The openwork surface 30 is integral with the protection unit 1, so that there is no mobility between the openwork surface 30 and the optical surface 10. As visible in FIGURES 3 and 4, the openwork surface 30 comprises a logo of the motor vehicle with which the protection unit 1 is mechanically coupled.

[0076] The solid parts 31 of the openwork surface 30 form parts opaque to the radiation 23 emitted and / or captured by the device 21 intended to be located behind the optical surface 10. The solid parts 31 are for example parts formed of material, while the at least one opening 32 of the openwork surface 30 forms a part free of material.

[0077] As can be seen in FIGURES 1 and 2, there is a non-zero clearance between the optical surface 10 and the openwork surface 30, such that the W wave transducer 13 is not mechanically coupled with the openwork surface 30. In other words, the openwork surface 30 is located at a distance from the W wave transducer 13, in order to allow mechanical decoupling between the W wave transducer 13 and the openwork surface 30.

[0078] In the embodiment illustrated in the, the openwork surface 30 is fixed integrally to the optical surface 10 by means of fixing lugs 16 integral with the optical surface 10.

[0079] In the embodiment illustrated in the, the openwork surface 30 is fixedly attached to a support 17 by means of fixing lugs 16 which extend through slots provided in the optical surface 10. Thus, the support 17 is located on the side of a first face 11A of the optical surface 10 – called the inner face – located on the side of the device 21 with which the protection unit 1 is intended to collaborate, and the openwork surface 30 is then located at the level of a second face 11B of said optical surface 10 – called the outer face – located opposite the openwork surface 30 and opposite the inner face. In other words, the support 17 and the openwork surface 30 are located on either side of the optical surface 10, relative to a direction of propagation of the radiation 23 emitted by the device 21.

[0080] In order not to hinder the propagation of the W waves on or through the optical surface 10, and as visible in FIGURES 1 to 3, the W wave transducer 13 is placed in an intermediate position between the fixing lugs 16 and the region of optical interest 12. In other words, at the level of the second face 11B of the optical surface 10, the transducer 13 is located between, on the one hand, an area of ​​the optical surface 10 at which the fixing lugs 16 pass or are fixed, and, on the other hand, a region of optical interest 12 formed by the region of the optical surface 10 at which the radiation 23 emitted and / or captured by the apparatus 21 is transmitted through said optical surface 10.

[0081] In the embodiments illustrated in FIGURES 1 to 4, a detection assembly 2 is also described comprising:

[0082] - a protection unit 1;

[0083] - at least one device 21 configured to capture and / or emit radiation 23 through the optical region of interest 12 of the optical surface 10 and through the at least one opening 32 of the openwork surface 30.

[0084] Thus, as visible in FIGURES 3 and 4, each device 21 collaborating with the protection unit 1 and its optical surface 10 is located opposite the at least one opening 32 of the openwork surface 30, in order to be able to effectively capture and / or emit the radiation 23 simultaneously through the optical surface 10 and the openwork surface 30.

[0085] Each device 21 is located opposite the optical surface 10, at a distance or against the optical surface 10, so that the radiation 23 emitted or captured by said at least one device 21 passes through the optical region of interest 12 of the optical surface 10.

[0086] Each device 21 is secured to the optical surface 10, so that each device 21 and the optical surface 10 are made immobile relative to each other.

[0087] In the example illustrated in the, the device 21 is fixed securely and directly to the optical surface 10, for example by gluing, screwing or snapping.

[0088] In the example illustrated in the, the device 21 is fixedly attached to a support 17 to which the optical surface 10 is also fixedly attached.

[0089] The transducer(s) 13 associated with the optical surface 10 are acoustically coupled to said optical surface 10 – and preferably mechanically coupled to it – in order to be able to generate W waves which propagate on the second face 11B of the optical surface 10 – in particular when the W wave transducer 13 is located on or on the side of the second face 11B – or through the optical surface 10, in particular when the W wave transducer 13 is located on or on the side of the first face 11A of the optical surface 10.

[0090] In the example illustrated in the, the W wave transducer 13 is located opposite the solid part 31 of the openwork surface 30 in order to hide it behind the solid part 31 of the openwork surface 30. In this exemplary embodiment, an electric wire 14 connected to each W wave transducer 13 extends opposite the solid part 31 of the openwork surface 30 in order not to be visible when looking at the openwork surface 30 from the front, as in the. Thus, the electric wire 14 extends towards a lateral edge of the optical surface 10 behind and opposite the solid part 31 of the openwork surface 30.

[0091] In the example illustrated in the, the W wave transducer 13 is misaligned relative to the openwork surface 30 and / or relative to its solid part 31. More particularly, in this exemplary embodiment, the W wave transducer 13 is located above the openwork surface 30. In this exemplary embodiment, an electric wire 14 connected to each W wave transducer 13 extends in a direction opposite to the openwork surface 30 and / or towards a lateral edge of the optical surface 10.

[0092] Each W wave transducer 13 is securely fixed to the optical surface 10 by any means, and in particular by gluing.

[0093] Each electrical wire 14 is fixed securely to the optical surface 10 by any means, and in particular by gluing.

[0094] In the embodiment illustrated in FIGURES 1 and 2, the W wave transducer 13 is located at the second face 11B of the optical surface 10, opposite the first face 11A of said optical surface 10 and at which the apparatus 21 is located. This configuration thus makes it possible to clean the second face 11B located opposite the openwork surface 30 more effectively.

[0095] In summary, the invention relates to a protection unit 1 of an apparatus 21 and a detection assembly 2 associating the apparatus 21 emitting or capturing radiation 23 through a region of interest of an optical surface 10 of the protection unit 1. The protection unit 1 further comprises at least one W wave transducer 13 configured to generate an acoustic W wave on or in the optical surface 10 in order to clean the optical region of interest 12. According to the invention, the protection unit 1 further comprises an openwork surface 30 located opposite the optical surface 10, the openwork surface 30 comprising a solid part 31 and at least one opening 32 through which the radiation 23 emitted and / or captured by the apparatus 21 can pass.

[0096] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention. In particular, the different characteristics, forms, variants and embodiments of the invention can be associated with each other in various combinations insofar as they are not incompatible or mutually exclusive. In particular, all the variants and embodiments described above can be combined with each other.

Claims

Protection unit (1) of an optical surface (10) intended to be associated with an apparatus (21) configured to capture and / or emit radiation (23) through a region of optical interest (12) of the optical surface (10), the protection unit (1) comprising: - the optical surface (10); - an openwork surface (30) integral with the optical surface (10) and placed opposite said optical surface (10), the openwork surface (30) comprising a solid part (31) and at least one opening (32) formed in the solid part (31); - at least one wave transducer (13) (W) mechanically coupled to the optical surface (10) and configured to generate a wave (W) propagating through the optical surface (10) and in the direction of and / or in the region of optical interest (12), the waves generated (W) by the at least one wave transducer (13) (W) are of the type of ultrasonic wave. Protective unit (1) according to the preceding claim, in which the perforated surface (30) is a grille, a radiator grille, a sheet metal part having at least one opening (32) or a bumper part having at least one opening (32). Protection unit (1) according to the preceding claim 1 or 2, in which the at least one transducer (13) of waves (W) is located opposite the solid part (31) of the perforated surface (30). Protection unit (1) according to any one of claims 1 to 3, in which the at least one transducer (13) of waves (W) is located on the side of a first face (11A) of the optical surface (10) – called the inner face – intended to be located on the side of the device (21) with which the protection unit (1) is intended to collaborate, opposite a second face (11B) of said optical surface (10) – called the outer face – located opposite the openwork surface (30), the waves (W) generated by the at least one transducer (13) of waves (W) being of the type of a core wave (W). Protection unit (1) according to the preceding claim, in which a wavelength of the wave (W) generated by the at least one transducer (13) of waves (W) is greater than or equal to twice a thickness of the optical surface (10) taken at the level of the optical region of interest (12). Protection unit (1) according to any one of claims 1 to 3, in which the at least one transducer (13) of waves (W) is located on the side of an outer face of the optical surface (10), located opposite the openwork surface (30), the waves (W) generated by the at least one transducer (13) of waves (W) being of the type of a Rayleigh wave (W). Protection unit (1) according to the preceding claim, in which a wavelength of the wave (W) generated by the at least one transducer (13) of waves (W) is less than or equal to one fifth of a thickness of the optical surface (10) taken at the level of the optical region of interest (12). Protective unit (1) according to any one of claims 1 to 7, in which the perforated surface (30) is fixedly fixed to a support (17) by means of fixing lugs (16) which extend through slots provided in the optical surface (10). Protective unit (1) according to any one of claims 1 to 7, in which the perforated surface (30) is fixed integrally to the optical surface (10) by means of fixing lugs (16) integral with the optical surface (10). Protection unit (1) according to any one of claims 8 or 9, wherein the at least one transducer (13) of waves (W) is placed in an intermediate position between the fixing lugs (16) and the region of optical interest (12). Detection assembly (2) comprising:- a protection unit (1) according to any one of the preceding claims;- at least one device (21) configured to capture and / or emit radiation (23) through the optical region of interest (12) of the optical surface (10) and through the at least one opening (32) of the perforated surface (30).

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