Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
  • G03B11/00—Filters or other obturators specially adapted for photographic purposes
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
  • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
  • G02B1/14—Protective coatings, e.g. hard coatings
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/0006—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means to keep optical surfaces clean, e.g. by preventing or removing dirt, stains, contamination, condensation
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B3/00—Simple or compound lenses
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
  • G03B17/00—Details of cameras or camera bodies; Accessories therefor
  • G03B17/02—Bodies
  • G03B17/08—Waterproof bodies or housings

Definitions

• the present invention relates to an optical system for a vehicle comprising a camera. It finds a particular but non-limiting application in motor vehicles.
• an optical system for a vehicle comprises: - a camera configured to acquire images of the external environment of said vehicle, - a protective glass configured to be placed facing said camera, said protective glass comprising an external face facing the exterior of said vehicle and an internal face facing said camera.
• the protective glass is configured to hide the camera so that it is not visible from outside the vehicle.
• a disadvantage of this state of the art is that the protective glass affects the performance of the camera due to the curved shape of the protective glass and/or its semi-transparency or opacity.
• the present invention aims to propose an optical system for a vehicle comprising a camera which makes it possible to resolve the mentioned drawback.
• the invention proposes an optical system for a vehicle comprising: - a camera configured to acquire images of the external environment of said vehicle, - a protective glass configured to be placed facing said camera, said protective glass comprising an external face facing the exterior of said vehicle, and an internal face facing said camera, characterized in that said internal face of said protective glass has a local radius of curvature R2 defined so that the protective glass has a focal length which tends towards infinity.
• said optical system may also include one or more additional characteristics taken alone or in all technically possible combinations, among the following.
• said camera is an RGB or infrared camera.
• said external face has a set of local radii of curvature R1.
• said internal face has a set of local radii of curvature R2.
• a protective glass for a vehicle configured to be placed facing a camera on board said vehicle, said protective glass comprising an external face facing the exterior of said vehicle, and an internal face facing said camera, characterized in that said internal face of said protective glass has a local radius of curvature R2 defined so that said protective glass has a focal length which tends towards infinity.
• the protective glass may also include one or more additional characteristics taken alone or in all technically possible combinations, among the following.
• said external face has a set of local radii of curvature R1.
• said internal face has a set of local radii of curvature R2.
• FIG. 1 illustrates an optical system for a vehicle comprising a camera and a protective glass arranged facing said camera, said protective glass comprising an external face and an internal face, according to a non-limiting embodiment of the invention
• FIG. 1 illustrates an optical transfer function curve of a camera of a prior art optical system with protective glass.
• the vehicle 2 is a motor vehicle.
• motor vehicle we mean any type of motorized vehicle. This embodiment is taken as a non-limiting example in the remainder of the description. In the remainder of the description, the vehicle 2 is thus otherwise called motor vehicle 2.
• the motor vehicle 2 comprises said optical system 1.
• the optical system 1 comprises: - a camera 10 configured to acquire images I1 of the external environment of said motor vehicle 2, the acquisition of the images I1 taking place in the image focus f' of the optical system 100 of the camera 10, - a protective glass 11 configured to be placed facing said camera 10.
• the optical system 1 is integrated into: - a logo, - a rotating logo, - a rear-view mirror, - a third brake light, otherwise called in English CHSML (“Center High Mounted Stop Lamp”), - in the trunk bar, - in the front grille of the motor vehicle 2, - at the rear of the motor vehicle 2.
• CHSML Center High Mounted Stop Lamp
• the protective glass 11 is part of the logo or pivoting logo.
• the camera 10 is an RGB camera or an infrared camera. In a non-limiting embodiment, the camera 10 is a FishEye TM camera.
• the camera 10 is used to: - parking assistance functions, functions called in English “rear view” or “surround view” (with a range of 0 to 30 meters in a non-limiting example), - a rearview mirror function (range of approximately 80 to 200 meters in a non-limiting example).
• the protective glass 11 is configured to hide the camera 10 from the outside of the motor vehicle 2 but also makes it possible to define a form of style particular to an automobile manufacturer. In non-limiting embodiments, it is semi-transparent or opaque or transparent.
• the protective glass 11 has a focus F and a focal length f and a field of vision FOV (illustrated on the ).
• the protective glass 11 also has a thickness d.
• the protective glass 11 comprises an external face 11.1 placed facing the exterior of the motor vehicle 2 and an internal face 11.2 placed facing the camera 10.
• the external face 11.1 is convex while the internal face 11.2 is concave or vice versa. In another non-limiting embodiment, the external face 11.1 is convex as well as the internal face 11.2, or the external face 11.1 is concave as well as the internal face 11.2.
• the protective glass 11 is made of PC (polycarbonate).
• the PC provides a robust external face, which does not break unlike PMMA (poly-methyl methacrylate).
• the protective glass 11 is made of PMMA.
• the external face 11.1 Due to the style shape of the protective glass 11, its external face 11.1 has a set of local radii of curvature R1 which are defined by the style shape.
• the internal face 11.2 has a set of local radii of curvature R2 adapted to the different local radii of curvature R1 of the external face 11.1.
• the focal length f of the protective glass 11 is as large as possible. This makes it possible to obtain an optically neutral protective glass 11.
• the focal length f thus tends towards infinity to avoid deflecting the light rays L1 coming from the outside onto the camera 10. Indeed, if the light rays L1 are deflected, this distorts the images I1 acquired by the camera 10 which results in less sharp I1 images.
• focal length f is as follows:
• the protective glass 11 includes the following characteristics: - n the refractive index of light equal to 1.58 for a protective glass 11 in polycarbonate, - the thickness d is 2.5mm (millimeters), - at the bottom of the protective glass 11, the external local radius of curvature R1 is equal to 150mm, - at the center of the protective glass 11, the external local radius of curvature R1 is equal to 177mm, and - at the top of the protective glass 11, the external local radius of curvature R1 is equal to 195mm.
• the internal local radius of curvature R2 is equal to 149.08mm
• the internal local radius of curvature R2 is equal to 176.08mm
• the internal local radius of curvature R2 is equal to 194.08mm.
• the drawing (b) of the illustrates a protective glass 11 with a focal length f whose internal face 11.2 includes a local radius of curvature R2 R1-(n-1)d/n.
• the focal length f is greater than the focal length f 0 .
• the field of vision FOV of the protective glass 11 is less than the field of vision FOV0 of the protective glass 31 of the prior art, which implies that the light rays L1 are less deviated and therefore they converge further towards the focus F.
• Figures 3 to 5 respectively illustrate optical transfer function curves, otherwise called FTO curves: - a camera 10 without protective glass, - a camera 10 arranged facing the protective glass 11 defined with an internal radius of curvature R2 adapted to have a focal length f which tends towards infinity, - a camera 10 placed opposite a protective glass 31 of the prior art defined with an unsuitable radius of curvature R2.
• the curves correspond to different angles of incidence (between 0° and 97°) of the light rays L1 which arrive on the optical system 100 of the camera 10.
• optical transfer function curves of the serve as a reference.
• An optical transfer function curve makes it possible to evaluate the ability of elements of an optical system such as a camera with or without protective glass to restore contrast depending on the fineness of the details of a target object; that is, its ability to transmit the spatial frequencies of the target object. It is used to evaluate the quality of the optical system 100. It thus makes it possible to evaluate the capacity of a protective glass 11 not to degrade the performance of the camera 10 compared to a camera 10 without protective glass or with a protective glass 31 of the prior art.
• the protective glass 11 of the optical system 1 makes it possible to obtain the same performance for the camera 10 which is placed opposite it as a camera 10 which has no protective glass.
• the protective glass 11 does not obstruct the camera 10.
• the invention described has in particular the following advantages: - it makes it possible to integrate a camera 10 behind a protective glass 11 without reducing the performance of the camera 10, - it makes it possible to keep the style given to the protective glass 11 by the car manufacturer because it does not modify its external face 11.1, - it makes it possible to obtain an optically neutral protective glass 11 by locally adapting the internal face 11.2 of the protective glass 11, - it is simple to implement.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Studio Devices (AREA)
• Lenses (AREA)
• Camera Bodies And Camera Details Or Accessories (AREA)
• Time Recorders, Dirve Recorders, Access Control (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=82943085

Family Applications (1)

Country Status (6)

Families Citing this family (1)

Family Cites Families (4)

• 2022
  • 2022-06-17 FR FR2205928A patent/FR3137614A1/fr active Pending
• 2023
  • 2023-06-06 US US18/875,236 patent/US20250370166A1/en active Pending
  • 2023-06-06 EP EP23731205.3A patent/EP4540657A1/de active Pending
  • 2023-06-06 JP JP2024573760A patent/JP2025519724A/ja active Pending
  • 2023-06-06 WO PCT/EP2023/065053 patent/WO2023241990A1/fr not_active Ceased
  • 2023-06-06 CN CN202380047557.8A patent/CN119384632A/zh active Pending

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