protection module and detection assembly for motor vehicles

Abstract

The invention relates to a protective unit for a device (21) and a detection assembly (2) associating the device (21) emitting or receiving radiation through an optical region of interest (12) of an optical surface (10) of the protective unit (1). The protective unit (1) further comprises at least one wave (W) transducer (13) configured to generate an acoustic wave (W) on or within the optical surface (10) in order to clean the optical region of interest (12). According to the invention, the protective unit (1) comprises at least one curved zone (123) located in an intermediate position between the transducer (13) and the optical region of interest (12) and having a radius of curvature greater than or equal to a wavelength of the wave (W) generated by the transducer (13). Figure to be published with the abbreviation: Fig. 1

Description

Title of the invention: protection module and detection assembly for a 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 allowing such cleaning to be carried out as well as 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 transducer for cleaning bodies in contact with the optical surface, by means of ultrasonic waves. By "cleaning", it is understood here that the 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 remove 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] The implementation of an electric field to control the hydrophobicity of a surface is also known, as described for example in KR 2018 0086173 AL 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 the liquid drops are to be removed 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, the use of a windshield wiper on a windshield of a motor vehicle is also known. This proven technique, however, has the disadvantage of disturbing a field of vision accessible to the driver. In addition, the successive passes of the windshield wiper lead to spreading the greasy particles deposited on the surface of the windshield. In addition, it is necessary to regularly renew the wiper linings which wear out during use. Finally, this technique is not or is difficult to use for cleaning sensors implemented on motor vehicles, such as, for example, lidars, proximity sensors or cameras.

[0007] For cleaning windshields or sensors implemented on motor vehicles, such as for example lidars, proximity sensors or cameras, cleaning methods are finally known for removing a 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 surface of the windshield.However, in order to obtain vaporization of a drop of liquid, a puddle or a film, the powers required to set the vibratory 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 drawbacks linked to their integration on more compact surfaces and / or with more complex and more irregular geometries than flat surfaces.

[0009] The object of the present invention is to propose a new protection unit in order to respond at least to a large extent to the preceding problems and to further lead to other advantages.

[0010] Another object of the invention is to be able to place the wave transducer further away from the region of optical interest to be cleaned on the optical surface.

[0011] Another aim of the invention is to limit, or even prevent, the wave transducer from disturbing the sensors associated with the optical surface.

[0012] Another aim of the invention is to allow the association of such wave transducers with optical surfaces having a more complex geometry.

[0013] 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:

[0014] - the optical surface;

[0015] - at least one wave transducer mechanically coupled to the optical surface and configured to generate a wave propagating through the optical surface and toward the region of optical interest;

[0016] Advantageously, the optical surface of the protection unit according to the invention comprises at least one curved zone situated in an intermediate position between the at least one transducer and the region of optical interest of the optical surface, relative to the propagation of the wave generated by the at least one transducer, the curved zone having a radius of curvature greater than or equal to a wavelength of the wave generated by the at least one transducer.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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 exclusively of the ultrasonic surface wave type, i.e. of the Rayleigh wave type. Such a surface wave propagates on the surface of the optical surface. A Rayleigh wave is preferred because a maximum proportion of the energy of the wave 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.

[0021] 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.

[0022] 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 apparatus 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 apparatus 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 from 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 from its region of optical interest.

[0023] 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.

[0024] In the context of the present invention, the curved area of ​​the optical surface is a portion of the optical surface located between the at least one wave transducer and the optical region of interest to which the waves generated by said at least one wave transducer are transported. The curved area thus forms a passage area for the ultrasonic surface waves. The curved area thus has a non-planar area. The curved area thus forms a concave or convex surface qualified by one or more non-infinite radii of curvature. Such curved areas are often an obstacle to the propagation of the surface waves generated by the at least one transducer. Thus, an essential contribution of the invention consists of qualifying and controlling the geometry of such curved zones in order to make them compatible with the use of wave transducers and thus allow a greater diversity of shapes and dimensions for the protection units.

[0025] 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.

[0026] Generally speaking, according to the invention, the at least one transducer is located in a plane different from the part of the optical surface to be cleaned by the waves generated by said at least one transducer. This advantageous configuration makes it possible to prevent the at least one transducer from disturbing or preventing the operation of the apparatus. In particular, this advantageous configuration makes it easier to locate the at least one wave transducer outside the region of optical interest, and therefore to prevent the at least one transducer from opposing the passage of the radiation emitted or captured by the apparatus through the optical surface taken at the level of its region of optical interest. Furthermore, this advantageous configuration makes it possible to associate the at least one transducer on the optical surface before integration of the protection unit according to the invention in a detection assembly.

[0027] Thus the protection unit according to 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.

[0028] The protection unit according to 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:

[0029] - the radius of curvature of the optical surface is greater than five times the length wavelength of the wave generated by the at least one transducer. Optionally, the radius of curvature of the optical surface is greater than ten times the wavelength of the wave generated by the at least one wave transducer. It is thus possible to use the trans wave conductors in configurations not previously envisaged. This advantageous configuration thus allows the propagation of ultrasonic surface waves from the at least one transducer towards the region of optical interest, through the curved zone;

[0030] - the at least one transducer is configured to generate only waves of surface which propagate on the surface of the optical surface towards the region of optical interest. More particularly, the waves thus generated are of the type of a Rayleigh wave making it possible to concentrate a maximum proportion of the energy of the wave at the level of the face of the optical surface on which it propagates. Consequently, this energy can be transmitted to a body, for example a raindrop, resting on the optical surface in order to detach it from the optical surface;

[0031] - the curved area of ​​the optical surface may comprise one or more segments concave and / or one or more convex segments. Each segment, concave or convex, has a radius of curvature that satisfies the condition mentioned above for the curved area. Each radius of curvature of each segment of the curved area of ​​the optical surface satisfies the condition mentioned above;

[0032] - the curved area can be formed by any part of the optical surface. In particular, it can be formed by any face of the optical surface, on the side of the device with which the protection unit is intended to collaborate or on the side opposite said device, or at an edge of the contact surface;

[0033] - according to a first variant embodiment, the curved zone of the optical surface comprises a single curved segment whose radius of curvature is greater than or equal to the wavelength of the wave generated by the at least one transducer. In this first variant embodiment, the radius of curvature of the single curved segment is preferably greater than five times the wavelength of the wave generated by the at least one transducer;

[0034] - according to a second embodiment, the curved zone of the optical surface comprises a plurality of curved segments, each curved segment having a radius of curvature greater than or equal to the wavelength of the wave generated by the at least one transducer. Advantageously, each curved segment has a radius of curvature greater than five times the Fonde wavelength generated by the at least one transducer;

[0035] - preferably, the optical surface takes the form of a plate. This confi advantageous configuration makes it easier to manufacture and shape, and also facilitates isotropic transmission of radiation through the optical surface. Preferably, the plate forming the optical surface is of constant thickness;

[0036] - the curved zone is located in an intermediate position between the at least one transducer and the region of optical interest, relative to a propagation path on the optical surface and in the direction of the waves generated by the at least one wave transducer. In other words, the optical surface has a geometry such that the implantation of the at least one transducer with respect to the optical surface leads to the waves generated by the at least one transducer passing through the curved zone of the optical surface;

[0037] - according to a first preferred embodiment of the invention, the at least one 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 - called the outer face intended to be located opposite the device relative to the inner face - the curved zone of the optical surface comprising an edge of the plate. Thus, in this advantageous configuration, the surface waves emitted by the at least one transducer, on the side of the inner face, must, in order to reach the region of optical interest at the level of the outer face of the optical surface, pass through the edge of the plate forming said optical surface. It is then appropriate that the edges of the plate delimiting the edge satisfy the conditions required and defined above to allow propagation of the surface waves.In this case, the area of ​​the optical surface comprising the edge and a portion of the proximal optical surface of the edges delimiting said edge forms the curved area within the meaning of the invention. In other words, each edge of the plate forming the optical surface, taken at the edge, is beveled so as to have a radius of curvature greater than or equal to the wavelength of the wave generated by the at least one transducer. Preferably, the radius of curvature of each beveled edge delimiting the edge of the optical surface is greater than five times the wavelength of the wave generated by the at least one transducer; .

[0038] - according to a second preferred embodiment of the invention, complementary or alternative to the first preferred embodiment of the invention, the optical surface comprises (i) a first part comprising the region of optical interest, and (ii) a second part situated in the extension of the first part, relative to the region of optical interest, the second part being oriented at a non-zero angle with respect to the first part, a radius of curvature between the first part and the second part being greater than or equal to the wavelength of the wave generated by the at least one transducer, the at least one transducer being integral with the second part.In this preferred embodiment of the invention, the first part of the optical surface is intended to be located opposite the apparatus intended to be associated with the protection unit according to the first aspect of the invention, while the second part of the optical surface is a functional zone of protection of the apparatus located outside a cone of emission or reception of the radiation respectively emitted or captured by the apparatus. The second part of the optical surface is the part on which the at least one transducer is. mechanically coupled in order to be able to generate the surface waves on the optical surface. This advantageous configuration thus makes it possible to easily place the at least one transducer outside the optical region of interest and to prevent any interference between the at least one wave transducer and the apparatus. In this second preferred embodiment of the invention, the curved zone is formed by the interface between the first part and the second part of the optical surface. Thus, the interface between the first part and the second part of the optical surface is not formed by a simple edge, but by a rounded area having a rounded area whose radius of curvature satisfies the required conditions described above. Preferably, in this second preferred embodiment of the invention, the radius of curvature of the curved area is greater than five times the wavelength of the wave generated by the at least one transducer;

[0039] - an angle between the first part and the second part is preferably a obtuse angle;

[0040] - the plate forming the optical surface has a thickness greater than or equal to 1 mm, taken at its smallest dimension.

[0041] According to a second aspect of the invention, there is proposed a detection assembly comprising:

[0042] - a protection unit according to the first aspect of the invention or according to one of any of its improvements;

[0043] - at least one device configured to capture and / or emit radiation through the region of optical interest of the optical surface.

[0044] 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.

[0045] 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:

[0046] - in the second preferred embodiment of the invention, the at least one apparatus is located opposite the first part of the optical surface;

[0047] - the at least one device is secured to the optical surface. In this variant of embodiment, the at least one device and the optical surface are made immobile relative to each other. According to a first variant embodiment, 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 may be glued to a front part of the at least one device. 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 securely attached to a support to which the optical surface is also securely attached. In this second embodiment variant, the optical surface and the at least one device comprise fastening members collaborating with the support, such as for example fastening screws or fastening clips;

[0048] - 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 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 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 the optical region of interest;

[0049] - 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 transducer 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 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.

[0050] 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.

[0051] Various embodiments of the invention are provided, integrating according to all of their possible combinations the different optional characteristics set out here.

[0052] 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 appended schematic drawings on the other hand, in which:

[0053] [Fig.l] illustrates a schematic front view of a detection assembly in accordance with second aspect of the invention and comprising a protection module in accordance with the first aspect of the invention;

[0054] [Fig.2] illustrates a schematic profile view of a first exemplary embodiment of a detection assembly in accordance with the second aspect of the invention and comprising a protection module in accordance with the first aspect of the invention;

[0055] [Fig.3] illustrates a schematic profile view of a second exemplary embodiment of a detection assembly in accordance with the second aspect of the invention and comprising a protection module in accordance with the first aspect of the invention;

[0056] [Fig.4] illustrates a schematic profile view of a third exemplary embodiment of a detection assembly in accordance with the second aspect of the invention and comprising a protection module in accordance with the first aspect of the invention;

[0057] [Fig.5] illustrates a schematic profile view of a fourth exemplary embodiment of a detection assembly in accordance with the second aspect of the invention and comprising a protection module in accordance with the first aspect of the invention.

[0058] 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.

[0059] 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.

[0060] In the figures, the elements common to several figures retain the same reference.

[0061] With reference to FIGURES 1 to 5, 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:

[0062] - the optical surface 10;

[0063] - at least one W wave transducer 13 mechanically coupled to the optical surface 10 and configured to generate a wave W propagating through the optical surface 10 and towards the region of optical interest 12. Each transducer 13 is connected to at least one electrical wire 14 which extends from a connection face 131 - preferably opposite the region of optical interest 12 - and towards an edge of the optical surface 10;

[0064] - at least one curved zone 123 located in an intermediate position between the at at least one transducer 13 and the region of optical interest 12 of the optical surface 10, relative to the Fonde propagation W generated by the at least one transducer 13, the curved zone 123 having a radius of curvature greater than or equal to a wavelength of the wave W generated by the at least one transducer 13.

[0065] In the context of the invention, the at least one electrical wire 14 may be of the type of an electrical cable comprising one or more electrical wires braided together and / or arranged inside an insulating sheath. Alternatively, each at least one electrical wire 14 may comprise a conductive element housed in an insulating sheath.

[0066] Furthermore, FIGURES 1 to 5 also illustrate the integration of such a protection unit 1 into a detection assembly 2 comprising:

[0067] - the protection unit 1 as described previously; and

[0068] - at least one device 21 configured to capture and / or emit radiation 23 at through the optical region of interest 12 of the optical surface 10.

[0069] The optical region of interest 12 corresponds to a part of the optical surface 10 located opposite the device 21 and at the level of which the radiation 23 emitted or captured by the device 21 passes through the optical surface 10.

[0070] The curved zone 123 of the optical surface 10 is a part of the optical surface 10 located between the W wave transducer 13 and the optical region of interest 12 towards which the W waves generated by the W wave transducer 13 are transported. The curved zone 123 thus forms a passage zone for the surface ultrasonic W waves generated by the W wave transducer 13.

[0071] The curved zone 123 thus has a non-planar zone. The curved zone 123 thus forms a concave or convex surface qualified by one or more non-infinite radii of curvature.

[0072] In all the embodiments illustrated in the FIGURES, the transducer 13 is located in a plane different from the part of the optical surface 10 to be cleaned by the waves W generated by said at least one transducer 13. In other words, the transducer 13 is always fixed integrally to a second part 121 of the optical surface 10 which is located in the extension of a first part 122 of the optical surface 10 comprising the optical region of interest 12, so that the second part 121 is not coplanar with the first part 122. Conversely, the second part 121 is connected to the first part 122 through the curved zone 123.

[0073] In other words, the transducer 13 is fixed integrally to a first face 11A or to a second face 11B of the optical surface 10, taken at the level of the second part 121 of said optical surface 10, so that the face 11A, 11B at the level of which the transducer 13 is fixed is located in a different plane from the second face 11B of the optical surface 10 taken at the level of the optical region of interest 12.

[0074] This advantageous configuration makes it possible to prevent the at least one transducer 13 from disturbing or preventing the operation of the device 21.

[0075] In order to ensure good cleaning, it is then necessary to dimension the curved zone 123 carefully.

[0076] The radius of curvature of the optical surface 10 is greater than five times the wavelength of the wave W generated by the transducer 13, or even greater than ten times the wavelength of the wave W in order to allow the propagation of the ultrasonic surface waves W from the at least one transducer 13 towards the optical region of interest 12, through the curved zone 123.

[0077] The curved zone 123 can be formed by any part of the optical surface 10. In particular, depending on the configurations, the curved zone 123 comprises a part of the first face 11A of the optical surface 10 and / or a part of the second face 11B of the optical surface 10.

[0078] Furthermore, the curved zone 123 of the optical surface 10 may comprise one or more concave segments 120 and / or one or more convex segments 120. In order to allow good propagation of the surface waves W through each segment 120 forming the curved zone 123, each segment 120, concave or convex, has a radius of curvature which satisfies the condition mentioned previously for the curved zone 123.

[0079] In the embodiments illustrated in FIGURES 2, 3 and 5, the curved zone 123 of the optical surface 10 comprises a single curved segment 120 whose radius of curvature is greater than or equal to the wavelength of the wave W generated by the transducer 13. More particularly:

[0080] - in the embodiment illustrated in [Fig.2], the second part 121 of the optical surface 10 to which the transducer 13 is attached extends perpendicular to the first portion 122 of the optical surface 10, towards the apparatus 21. Thus, the optical surface 10 takes the form of a folded plate - the fold forming the curved zone 123. In this exemplary embodiment, the transducer 13 is located behind the region of optical interest 12, at a lateral or upper edge of the apparatus 21. Thus, the waves W generated by the transducer 13 reach the region of optical interest 12 - at the second face 11B of the optical surface 10 - by passing through the fold of the optical surface 10 forming the single segment 120 of the curved zone 123;

[0081] - in the embodiment illustrated in [Fig.3], the optical surface 10 takes the form of a flat plate which extends exclusively in front of the apparatus 21. The second part 121 of the optical surface 10 to which the transducer 13 is attached thus extends in the extension and in a coplanar manner with the first part 122 of the optical surface 10, beyond a lateral or upper edge of the apparatus 21. In this exemplary embodiment, the transducer 13 is fixed integrally to the first face 1 IA of the optical surface 10, the one located opposite the device 21. To reach the optical region of interest 12 - at the level of the second face 1 IB of the optical surface 10 - the waves W generated by the transducer 13 pass through a slice of the optical surface 10, formed by a peripheral edge of said optical surface 10. In order to allow this propagation, and in accordance with the present invention, the peripheral edge of the optical surface 10 is shaped in order to form the curved zone 123: the rear of the plate is curved, so as to form the single segment 120 of the curved zone 123;

[0082] - in the embodiment illustrated in [Fig.5], the second part 121 of the optical surface 10 to which the transducer 13 is attached extends inclined to the first portion 122 of the optical surface 10, towards the apparatus 21. Thus, the optical surface 10 takes the form of a folded plate - the fold forming the curved zone 123. In this exemplary embodiment, the transducer 13 is located behind the region of optical interest 12, at a lateral or upper edge of the apparatus 21. Thus, the waves W generated by the transducer 13 reach the region of optical interest 12 - at the second face 11B of the optical surface 10 - by passing through the fold of the optical surface 10 forming the single segment 120 of the curved zone 123.

[0083] Alternatively, the curved zone 123 may also comprise several segments 120. Thus, in the embodiment illustrated in [Fig. 4], the second part 121 of the optical surface 10 to which the transducer 13 is attached extends inclined relative to the first part 122 of the optical surface 10, in the direction of the apparatus 21. Furthermore, the transducer 13 is fixed integrally to the first face 1 IA of the optical surface 10, the one located on the side of the apparatus 21. Thus, to reach the optical region of interest 12 - at the level of the second face 1 IB of the optical surface 10 - the waves W generated by the transducer 13 pass through a slice of the optical surface 10, formed by a peripheral edge of said optical surface 10.In order to allow this propagation, and in accordance with the present invention, the peripheral edge of the optical surface 10 is shaped in order to form a first segment 120 of the curved zone 123: the rear of the plate is curved, so as to form the single segment 120 of the curved zone 123. Further on, the W waves generated by the transducer 13 reach the fold of the optical surface 10 distinguishing on the one hand the first part 122 of the optical surface 10, from its second part 121 on the other hand. In order to allow the propagation of the W waves through the fold, said fold has a radius of curvature which satisfies the conditions imposed by the invention. The fold forms a second segment 120 of the curved zone 123. In general, the example illustrated in [Fig. 4] is a combination of the embodiments illustrated respectively in FIGURES 3 and 5. .

[0084] Of course, the invention addresses any combination of the embodiments described above.

[0085] According to a preferred embodiment of the invention, but not limiting, the apparatus 21 is of the type of an optical remote sensing apparatus 21, such as for example a lidar, a photographic apparatus 21, a camera, a radar, an infrared sensor and an ultrasonic rangefinder.

[0086] In summary, the invention relates to a protection unit 1 for an optical surface 10 of an apparatus 21 and a detection assembly 2 associating the apparatus 21 emitting or capturing radiation 23 through a region of interest of the 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 comprises at least one curved zone 123 located in an intermediate position between the transducer 13 and the optical region of interest 12 and having a radius of curvature greater than or equal to a wavelength of the W wave generated by the transducer 13.

[0087] 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

1.

2.

3. Claims Protection unit (1) of an optical surface (10) intended to be associated with a device (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); - at least one transducer (13) of waves (W) mechanically coupled to the optical surface (10) and configured to generate a wave (W) of the type of an ultrasonic wave propagating through the optical surface (10) and in the direction of the region of optical interest (12); wherein the optical surface (10) comprises at least one curved zone (123) located in an intermediate position between the at least one transducer (13) and the optical region of interest (12) of the optical surface (10), relative to the propagation of the wave (W) generated by the at least one transducer (13), the curved zone (123) having a radius of curvature greater than or equal to a wavelength of the wave (W) generated by the at least one transducer (13), and the transducer (13) is fixedly attached to a second part (121) of the optical surface (10) which is located in the extension of a first part (122) of the optical surface (10) comprising the optical region of interest (12), so that the second part (121) is connected to the first part (122) through the curved zone (123), and the transducer (13) is fixedly attached to a first face (1 IA) or to a second face (1 IB) of the optical surface (10),taken at the second part (121) of said optical surface (10), so that the face (1 IA, 1 IB) at which the transducer (13) is fixed is located in a different plane from the second face (1 IB) of the optical surface (10) taken at the optical region of interest (12), the angle between the first part and the second part being an obtuse angle., Protection unit (1) according to the preceding claim, in which the radius of curvature is greater than five times the wavelength of the wave (W) generated by the at least one transducer (13). Protection unit (1) according to any one of the preceding claims, wherein the at least one transducer (13) is configured to generate only surface waves (W) which propagate on the surface of the optical surface (10) towards the optical region of interest (12).

4. Protection unit (1) according to any one of claims 1 to 3, in which the curved zone (123) of the optical surface (10) comprises a single curved segment (120) whose radius of curvature is greater than or equal to the wavelength of the wave (W) generated by the at least one transducer (13).

5. Protection unit (1) according to any one of claims 1 to 3, in which the curved zone (123) of the optical surface (10) comprises a plurality of curved segments (120), each curved segment (120) having a radius of curvature greater than or equal to the wavelength of the wave (W) generated by the at least one transducer (13).

6. A protection unit (1) according to any preceding claim, wherein the optical surface (10) takes the form of a plate.

7. Protection unit (1) according to the preceding claim, in which the at least one transducer (13) is located on the side of a first face (11 A) 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 (1 IB) - called the outer face intended to be located opposite the device (21) relative to the inner face - the curved zone (123) of the optical surface (10) comprising an edge of the plate.

8. Detection assembly (2) comprising: - a protection unit (1) according to any one of the preceding claims; - at least one apparatus (21) configured to capture and / or emit radiation (23) through the optical region of interest (12) of the optical surface (10).

9. Motor vehicle comprising a detection assembly (2) according to the preceding claim.

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