Side camera with IR radiation source for a vehicle

Abstract

The invention relates to a side camera (100) for a vehicle (101), comprising - a housing (1) having a housing interior (R) and a housing opening (O), - a camera (2) and - a protective pane (3), which is provided in the housing opening (O) and which has an interior-side surface (II) facing the housing interior (R) and an exterior-side surface (I) facing away from the housing interior (R). The camera (2) is provided in the housing interior (R) and is oriented towards the protective pane (3) so that the camera can capture images through the protective pane (3), said protective pane (3) being made of transparent glass. The side camera is characterized in that a radiation source (4) for IR radiation (5) in the IR wavelength range of 1.3 µm to 3.5 µm is positioned relative to the protective pane (3) so that the exterior-side surface (I) can be freed of water (6) at least in a heating region (P) by means of the IR radiation (5) of the radiation source (4).

Description

[0001] Side camera with IR radiation source for a vehicle

[0002] The invention relates to a side camera for a vehicle, a vehicle with such a side camera and a method for removing moisture using the side camera.

[0003] Vehicles, particularly passenger cars (PCs), typically have side mirrors in addition to a rearview mirror mounted inside the vehicle, which can be used to observe and monitor rearward traffic. Side mirrors have the disadvantage that they usually protrude significantly on both sides of the vehicle, causing difficulty when parking, increasing aerodynamic drag while driving (which generates wind noise), and reducing the vehicle's fuel efficiency. Furthermore, the structure of the side mirror creates a blind spot that is difficult to control using only the driver's field of vision, and such a blind spot is one of the main causes of traffic accidents.

[0004] To solve these problems, more and more vehicles, especially electric vehicles, are equipped with side cameras instead of side mirrors. A combination of side cameras and side mirrors is also known. Such side cameras typically have a housing with a camera mounted inside, designed to film rear traffic and transmit the recorded images to a display inside the vehicle. To better protect the fragile lens of the side camera, such side cameras typically have a transparent protective screen installed in front of the camera lens in the side camera housing.

[0005] A general challenge when driving is heating vehicle windows to prevent icing or fogging, which impairs visibility. There are numerous solutions for removing moisture from vehicle windows. Typically, vehicle windows are freed of moisture by, for example, blowing heated air onto the window via inlets. This type of heating is summarized under the heating, ventilation, and air conditioning (HVAC) method. Alternatively, vehicle windows also have electrically conductive coatings, particularly silver coatings. The coatings are electrically contacted so that a current can be passed through them. This heats up the coating, which is the basis for the heating effect. For example, see WO2013 / 104438 A1.One problem with electrically conductive coatings is their often high surface resistance, which makes heating inefficient. The coating also reduces the transparency of such windows. Another major disadvantage of these moisture removal solutions is that the heating and subsequent evaporation of the water by convection or conduction requires the temperature of the vehicle window to adjust. The vehicle window must be heated until a suitable temperature is reached to remove fog and frost. This process is time-consuming and energy-inefficient.

[0006] FR960125A shows vehicle windshields with IR radiation sources. If water droplets or frost have deposited on the windshield, they can be irradiated using an IR radiation source, causing any watery films on the windshield to evaporate. In DE102014220652A1, JP2014104841A, and US20110067726A1, the IR radiation source is arranged on a long side of the vehicle windshield, so that the IR radiation is directed into the vehicle windshield and decoupled at the point where the water deposits. The IR radiation heats the water, causing it to evaporate. DE102014006532A1 discloses a device that is attached to an inner side of the windshield in such a way that the emitted rays are emitted at a specific angle to the inner side and are coupled into the windshield via the inner side and guided by it. The radiation emitted by the device corresponds to the resonant frequency of water.

[0007] DE102017210359A1 discloses a method for controlling a heating device for a transparent medium of a means of transport, with which the transparent medium can be quickly and reliably tempered without overheating a camera arranged in or on the means of transport. The heating device can be designed as an IR heating device. The method steps are: providing a camera arranged in or on the means of transport, wherein the camera comprises an IR-sensitive sensor; receiving IR light emitted by the heating device for the transparent medium by the IR-sensitive sensor of the camera; evaluating the IR light received by the IR-sensitive sensor to determine a current temperature of the transparent medium; and reducing the heating power of the heating device if the current temperature of the transparent medium is above a predefined target temperature.

[0008] DE102019206376B4 discloses a window pane with a heating device, wherein the heating device comprises at least one lighting unit for providing infrared light, wherein the at least one lighting unit is arranged on the window pane and is designed to couple the provided infrared light into the window pane via a coupling unit arranged between the window pane and the at least one lighting unit, and the window pane is designed as a light guide for transmitting the coupled-in light by means of internal reflection, wherein an outcoupling region is arranged on the window pane, which has at least one outcoupling deflection structure, which is designed as an optical grating, which is designed to couple the transmitted light, which falls on the outcoupling region, out of the window pane in at least one direction determined by the at least one outcoupling deflection structure.

[0009] US2022030671A1 discloses an exterior trim assembly for a vehicle, comprising a panel made of a thermoplastic material, a heating device with an infrared radiator for emitting infrared rays towards the panel, and a housing structure for accommodating the heating device, wherein the panel is transparent to electromagnetic radiation in at least one of the ranges for radio waves, infrared radiation, visible light, and ultraviolet radiation, the housing structure opens towards the panel with an opening, and the panel extends over the opening of the housing structure.

[0010] From the disadvantages mentioned above, the task can be derived to provide a side camera with a protective screen whose protective screen can be freed from frost and fogging by water in a space-saving, energy-efficient and quick manner.

[0011] The object of the present invention is achieved by a side camera according to claim 1, a vehicle with such a side camera according to claim 12, and a method for removing moisture using the side camera according to the invention according to claim 14. Preferred embodiments are evident from the subclaims.

[0012] The invention relates to a side-view camera for a vehicle. The side-view camera comprises a housing with a housing interior and a housing opening, a camera, and a protective screen. The protective screen is arranged in the housing opening and has an interior surface facing the housing interior and an exterior surface facing away from the housing interior. The camera is arranged in the housing interior and directed towards the protective screen. This means that the camera can record images through the protective screen. The camera is therefore arranged in the housing interior in such a way that it can receive visible radiation transmitted through the protective screen. The lens of the camera therefore faces the protective screen. The protective screen is provided to protect the camera located in the housing from moisture and mechanical damage and at the same time enables the camera to record images from outside the side-view camera.

[0013] According to the invention, the side camera comprises a radiation source for IR radiation in the IR wavelength range from 1.3 pm to 3.5, which is arranged in relation to the protective screen in such a way that the outer surface of the protective screen can be freed of water at least in a heating area by means of IR radiation from the radiation source. In other words: the radiation source irradiates the heating area of ​​the protective screen with IR radiation either directly from outside the housing interior or preferably from the housing interior, or alternatively, the radiation source is arranged in relation to the protective screen in such a way that the IR radiation is coupled into the protective screen during operation of the radiation source and is coupled out at the area of ​​the protective screen provided with a watery coating.In the sense of the invention, a mixture of both variants is also possible, i.e. a first radiation source irradiates at least the heating area directly and a second radiation source frees at least the heating area of ​​water by coupling and decoupling.

[0014] The side camera is intended to be a component of a vehicle. For example, the side camera can be mounted on a vehicle instead of a side mirror. However, the side camera can also be designed so that it can be mounted on the vehicle, for example, with a side mirror, in particular on a side mirror. The camera is preferably a video camera.

[0015] The outer surface of the protective screen is the surface exposed to the external environment. "Exposed to the external environment" in the context of the invention means that the surface is directly adjacent to the external environment, allowing moisture contained in the air to condense on the exposed surface of the protective screen. The outer surface can have a functional coating or be coating-free. In other words, the outer surface can be formed by the uncoated surface of the protective screen or by a coating applied to the surface of the protective screen.

[0016] The radiation source is arranged such that at least the heated area of ​​the protective screen is freed of water. The heated area is simultaneously the camera's field of view, i.e., the area of ​​the protective screen through which the camera "looks," i.e., through which the camera records images. Preferably, the radiation source is arranged relative to the protective screen such that at least 50% of the outer surface, preferably at least 70% of the outer surface, in particular the entire outer surface of the protective screen, can be freed of water using the IR radiation.

[0017] The invention is based on the fact that the water molecules of the water deposited on the exposed surface are caused to vibrate by IR radiation, which consequently heats the water. The heating of the water condensed or frozen on the exposed surface occurs largely selectively, since glass panes themselves typically absorb IR radiation much less strongly, and therefore only negligible heating of the protective screen occurs. A resulting advantage is the efficient removal of fog or frost from the side camera window. Heating using HVAC would be very complex, since side cameras are usually mounted on the outside of the vehicle's outer skin. The inventors have also discovered that evaporation using IR radiation can be many times faster than with the HVAC / coating variant.

[0018] The protective pane is preferably a monolithic pane. "Monolithic pane" refers to single glazing, which may, however, be provided with functional coatings such as an IR-reflective coating and / or a LowE coating (emissivity-reducing coating). It is understood that the IR-reflective coating must not be positioned in such a way that it can impede the IR radiation from the radiation source in the direction of the heating area of ​​the protective pane; thus, the coating must not be positioned between the heating area and the radiation source. Such coatings are advantageously applied to the interior-facing surface. The IR-reflective coating can, for example, be positioned on the interior-facing surface of the protective pane if the IR radiation source is positioned in such a way that the IR radiation is coupled into the protective pane.Depending on the coupling variant, a section of the interior surface can be free of the IR-reflective coating, for example the section through which the radiation source couples. Using the coating in this way, water deposits can be removed even more effectively, as the coating reduces coupling into the interior of the housing and instead reflects the radiation into the outside environment. The camera can also be better protected from IR radiation. The protective screen has a circumferential edge with an edge surface, which particularly preferably comprises an upper edge and a lower edge as well as two side edges running in between. The upper edge refers to the edge that points upwards when installed in the side camera. The lower edge refers to the edge that points downwards when installed in the side edge.The protective screen may have any suitable geometric shape and / or curvature. The protective screen preferably has a substantially circular peripheral edge.

[0019] According to the invention, the radiation source is designed such that it can emit IR radiation in the IR wavelength range from 1.3 pm to 3.5 pm. In a first preferred embodiment of the vehicle according to the invention, the radiation source is designed such that it can emit IR radiation in the IR wavelength range from 1.8 pm to 3.4 pm, preferably from 1.9 pm to 3.3 pm, particularly preferably from 1.9 pm to 3.0 pm. Alternatively, the radiation source is designed such that it can emit IR radiation in the IR wavelength range from 1.4 pm to 2 pm, preferably from 1.45 pm to 1.95 pm. In this alternative range, the IR radiation is particularly energy-intensive and thus very suitable for evaporating water. This wavelength range is particularly preferred when the radiation source comprises or consists of an LED, since LEDs with IR radiation in higher wavelength ranges from 2 pm are difficult to manufacture and can therefore be costly.It is not necessary for the emission band of the radiation source to completely cover the specified ranges. However, the emission band should lie (at least partially) within these ranges. The radiation source is expediently connected to a power supply. It is precisely in this preferred wavelength range that the absorption and excitation of water molecules, and thus the resulting heating and evaporation, are particularly high. Advantageously, it has been shown that with glass, the transmission in the wavelength range from 2.9 pm to 3.1 pm is particularly high at over 70%, and especially at approximately 3.0 pm at approximately 85%, so that the energy can be used efficiently for defrosting and evaporating water.

[0020] In a further optimized first embodiment, the emission bands of the radiation source lie exclusively in the IR wavelength range from 1.3 pm to 3.5 pm, particularly preferably in the IR wavelength range from 1.8 pm to 3.4 pm, very particularly preferably in the IR wavelength range from 1.9 pm to 3.3 pm and in particular in the IR wavelength range from 1.9 pm to 3.0 pm. This allows the radiation source to be made more compact, which lowers material costs and reduces the complexity of the structure. By limiting the wavelength range to the most effective wavelength for evaporation, energy efficiency can also be improved. Alternatively, the emission bands of the radiation source lie exclusively in the IR wavelength range from 1.4 pm to 2 pm, preferably from 1.45 pm to 1.95 pm. The removal of frost and moisture is particularly effective in this range.

[0021] The radiation source preferably comprises an LED, OLED, a laser, and / or a laser diode. The radiation source preferably comprises an LED, which can also be referred to as an "IR radiation-emitting diode." Furthermore, the radiation source can comprise laser diodes or lasers, which have the advantage of being particularly powerful and efficient. In addition to the aforementioned radiation sources for generating IR radiation, the radiation source can also comprise a housing in which the radiation sources for generating IR radiation are arranged. Alternatively, the radiation source can consist of an LED, OLED, a laser, and / or a laser diode.

[0022] In a particularly preferred embodiment of the invention, the radiation source comprises or consists of an Er:YAG diode. The Er:YAG diode has a wavelength of approximately 2960 nm. This wavelength corresponds to the wavelength range in which water molecules exhibit the highest absorption coefficient. Other examples are InAs / GaSb and Er3+-doped sesquioxide diodes.

[0023] In a particularly preferred embodiment of the invention, the radiation source is a fiber-bulk hybrid laser. The laser preferably comprises the laser medium Cr:ZnSe / S. The laser is dimmable, for example, preferably within a range of 1.9 pm to 3.0 pm, so that the wavelength or a wavelength range of the emitted IR radiation can be selected as needed.

[0024] The radiation source(s) can be strip-shaped or spot-shaped, for example. Other geometric shapes are also possible. Several individual radiation sources can also be arranged next to each other, spaced apart, or in a strip-shaped configuration (close to each other). In other words, if several spot-shaped LEDs are arranged next to each other, a multi-part, strip-shaped radiation source can be formed. This allows the number and intensity of the radiation sources to be flexibly adapted to the requirements for heating the protective screen, for example, with regard to the spatial and geometric conditions and the energy required for efficient heating.In the event that the radiation source directly irradiates the outer surface of the protective screen, at least in the heating area, a scattering element, preferably an optical concave lens (also called a diverging lens), a microlens array, or a holographic lens, is preferably arranged between the radiation source and the outer surface of the protective screen. The scattering element serves to scatter the IR radiation. Parallel incident IR rays are refracted by the scattering element in such a way that the IR rays are scattered in space. The radiation source is therefore preferably aligned such that the IR radiation emitted by it is scattered by the scattering element, whereby, for example, the IR radiation from a laser can irradiate a larger area of ​​a surface of the protective screen.

[0025] According to the invention, the protective pane is made of transparent glass, in particular soda-lime glass, which is common for window panes. In principle, however, the protective pane can also be made of other types of glass (e.g. borosilicate glass, quartz glass, aluminosilicate glass). In particular, the protective pane is a glass pane with an iron oxide content of a maximum of 1 wt.%, preferably a maximum of 0.5 wt.%, particularly preferably a maximum of 0.1 wt.%. The thickness of the pane can vary widely. Preferably, panes with a thickness in the range of 0.8 mm to 5 mm, preferably 1.4 mm to 2.5 mm, for example those with the standard thicknesses of 1.6 mm or 2.1 mm, are used. The protective pane can be partially toughened, tempered, or not. If the protective pane is to be toughened, this can be thermal or chemical.

[0026] The protective screen can have any three-dimensional shape. Preferably, the protective screen has no shadow zones, allowing it to be efficiently coated by cathode sputtering. The protective screen is preferably flat or slightly or strongly curved in one or more directions of space.

[0027] The housing may, for example, comprise metal, carbon fiber and / or plastic.

[0028] The side camera is intended to be part of a vehicle and the camera in the side camera is intended to film the traffic behind. Alternatively or additionally, the camera can also be intended to film the traffic to the side or the traffic in front. According to the invention, the protective screen is at least transparent enough that the camera can receive images through it and at the same time is transparent enough for IR radiation that the IR radiation emitted by the radiation source can be guided through the protective screen or, in the case of direct irradiation of the protective screen, the IR radiation can at least be sufficiently transmitted through the protective screen to reach the outer surface. The protective screen preferably has a light transmittance for visible light (according to ISO 9050:2003) of at least 50%, preferably of at least 70%, in particular of at least 90%."Visible light" refers to light with a wavelength of 380 nm to 780 nm. The protective screen preferably has a transmittance for IR radiation (at least in the wavelength range from 1.3 pm to 3.5 pm) of at least 30%, preferably at least 50%, in particular at least 70%. With regard to the determination of the light transmittance according to ISO 9050:2003 (see point 3.3 of the standard), the relative spectral distribution of illuminant D65 (see, for example, ISO 11664-2:2007) and / or the relative spectral distribution of illuminant A (see, for example, ISO 11664-2:2007) can be used for the determination. In other words, the described light transmittance ranges apply to the determination using illuminant A and / or illuminant D65. The IR transmittance of the protective screen can be determined by spectrophotometric tests according to ISO 9050.

[0029] “Transparent” in the sense of the invention means a light transmission (according to ISO 9050:2003) for visible light of at least 50%, preferably at least 60% and particularly preferably at least 70%.

[0030] In a second preferred embodiment of the invention, which can also be combined with the first embodiment, in addition to the camera, at least one radiation source is also arranged in the housing of the side camera. The radiation source is arranged in the housing in such a way that it can irradiate the interior surface of the protective screen, at least in the heating area. During operation, the radiation source irradiates the protective screen, so that at least a portion of the IR radiation emitted by the radiation source is transmitted through the protective screen and exits at least in the heating area of ​​the exterior surface of the protective screen. The “at least partial transmission through the protective screen” means that at least significant portions of the IR radiation are transmitted through the protective screen, so that the exterior surface of the protective screen in the heating area can be freed of water deposits and / or frost.Direct irradiation has the significant advantage that the heated area can be effectively cleared of water without requiring a complex structure from the radiation source to the protective screen. Due to the less complex structure, the radiation source may also require more space, for example, due to a powerful radiation source. The radiation source can also be positioned in such a way that it can also clear the camera lens of water deposits in addition to the protective screen.

[0031] In a third embodiment, which is an alternative to the second embodiment, the radiation source is arranged relative to the protective pane in such a way that the IR radiation emitted by the radiation source can be at least partially coupled into the protective pane and spreads by total internal reflection at least in the heating area of ​​the protective pane. The term "at least partial coupling" means that at least significant portions of the IR radiation are coupled into the protective pane, so that the outer surface of the protective pane in the heating area can be freed of water deposits and / or frost. It is understood that 100% coupling of IR radiation without radiation losses is never possible. At the same time, the partial coupling of IR radiation does not mean an unavoidable and negligible coupling portion of the IR radiation, which can occur, for example, with direct irradiation, as described in the second embodiment.The coupled IR radiation is coupled out into the adhering water on the outer surface due to the lower refractive index of water compared to the protective screen. The IR radiation is absorbed and the water molecules in ice crystals and water droplets are excited by the IR radiation, causing the ice to melt and the water to evaporate. Energy loss through convection is advantageously largely eliminated.

[0032] The IR radiation can, for example, be coupled in via an edge surface of the protective pane. For this purpose, the radiation source can be arranged in a recess in the protective pane. This recess in the protective pane is preferably a hole, i.e. a feedthrough, which extends between the interior and exterior surfaces of the protective pane. Alternatively, the recess can also be a depression in the manner of a blind bore (blind-like depression), which extends from the interior or exterior surface into the pane without, however, reaching the opposite surface, which would result in a feedthrough. The radiation source is arranged in the recess in such a way that it can couple the IR radiation into the pane via the edge surface of the recess. The recess can be created in the pane, for example, by mechanical drilling or laser processing.The recess is preferably round, but can in principle have any desired shape, for example, even a polygonal shape. This refers to the base area of ​​the recess in the plane of the at least one surface of the disc over which the recess is introduced into the disc. The recess has the overall shape of a cylinder, preferably a vertical cylinder. The cylinder is preferably a circular cylinder (circular base area), but can also have any other base area, for example, an elliptical base area (elliptical cylinder) or a polygonal base area (prism).

[0033] The recess, whether in the form of a feedthrough or a depression, is delimited by a circumferential edge surface which extends between the interior surface and the exterior surface of the protective screen. In the case of a feedthrough, this is the only delimiting surface of the recess. In the case of a bag-like depression, there is a further delimiting surface which faces the surface of the protective screen to which the depression does not extend and which, as it were, forms the bottom of the blind bore. The radiation source is arranged on a section of the edge surface of the recess in the protective screen, preferably attached, in particular glued, or arranged in a holder fastened to the recess. The IR radiation is then coupled into the protective screen via the edge surface of the recess and, due to the lower refractive index of water, selectively in the case of icing ordecoupled from the interior of the protective screen at points where moisture has condensed.

[0034] Alternatively, the radiation source can be arranged on at least a portion of the peripheral edge surface of the pane. The radiation source is, for example, assigned to at least one side edge surface or attached to two opposite side edge surfaces and / or to the upper and / or lower edge of the protective pane, for example, glued or arranged in a mount attached to the pane. Preferably, the radiation source is arranged along the entire peripheral edge surface of the protective pane, for example, in a band.

[0035] As an alternative to being arranged in a recess in the pane or on a section of the circumferential edge, the radiation source can also be arranged on the interior surface of the protective pane. In this variant, an IR mirror layer, i.e. a reflective coating for the infrared range, is applied to the exterior surface of the protective pane, which, when viewed through the protective pane, overlaps the radiation source. The radiation source is arranged such that, during operation, it irradiates the protective pane via the interior surface. For this purpose, the radiation source is preferably attached to the interior surface of the protective pane, for example, adhered with an optically clear adhesive (OCA).The IR radiation enters the protective pane via the interior surface, is transmitted through it, exits the exterior surface of the protective pane, and is then reflected by the IR reflective layer at an angle suitable for coupling into the protective pane. This reduces the complexity of the glazing, as the radiation source does not have to be arranged on the edge surfaces of the pane, in particular not in a recess in the pane. An optically clear adhesive is preferably a material that contains or is made from polyacrylate compounds (e.g., polyacrylate or polymethylacrylate) or silicone. By "clear" in the sense of the invention, we mean that the adhesive is transparent. The position of the radiation source and the IR reflective layer can also be reversed, i.e., the radiation source can be arranged on the exterior surface and the IR reflective layer on the interior surface of the protective pane.

[0036] When using an IR mirror coating, the IR radiation from the radiation source is (at least partially) reflected back toward the protective screen by the IR mirror coating, where the IR radiation is coupled into the protective screen using the principle of total internal reflection. This helps distribute the IR radiation within the protective screen and transfer it to the areas to be heated, i.e., the icy or moist heating area of ​​the protective screen.

[0037] IR mirror layers are known per se and can be formed, for example, as a silver-containing coating or as a layer of an electrically conductive oxide (transparent conductive oxide, TCO), such as indium tin oxide (ITO). Alternatively, the IR mirror layer can also be arranged on the pane in the form of a coated thermoplastic film, for example made of polyethylene terephthalate (PET). The IR mirror layer is preferably a prism film, which can additionally be coated with an IR-reflecting coating based on an electrically conductive oxide. In particular, the IR mirror layer is a microprism film, which can additionally be coated with an IR-reflecting coating based on an electrically conductive oxide.The inclined surfaces of the prism film cause the IR rays to be reflected at a particularly advantageous angle by the IR mirror layer, so that they hit the screen at an angle of incidence at which a particularly high proportion of the IR radiation can be coupled in. Alternatively, the outer surface of the protective screen, in the area covering the radiation source, can be surface-treated so that the surface of the protective screen in this area has inclined surfaces that are particularly well-suited for coupling in the IR radiation. The thus treated surface of the protective screen is preferably additionally provided with an IR-reflective coating.

[0038] Alternatively, the radiation source can be applied to the outside surface or the inside surface of the protective screen using an optically clear adhesive in the shape of an oblique wedge. The radiation source is preferably applied in the edge region of the protective screen. For the purposes of the invention, "oblique wedge" refers to a wedge shape having two substantially triangular side surfaces, two base surfaces, and one base surface. The base surfaces and the base surface can have any shape conceivable in this context, for example, substantially rectangular, triangular, or round, preferably substantially rectangular. The triangular side surfaces are not rectangular, so that the two base surfaces are different sizes.The base surface is the smallest of the surfaces of the inclined wedge and is arranged at an angle greater than 90° to one of the base surfaces and at an angle less than 90° to the other base surface. In this embodiment, the optically clear adhesive is applied to the protective screen such that the base surface is at an angle of less than 90° to the base surface of the wedge, which is in contact with the surface of the protective screen. The radiation source is arranged such that the IR radiation is first transmitted through the optically clear adhesive before subsequently penetrating the screen, with the IR radiation being at least partially coupled into the protective screen by utilizing the effect of total internal reflection. The radiation source is arranged such that, during operation, it irradiates the base surface of the optically clear adhesive, with the emitted IR radiation preferably impinging on the optically clear adhesive perpendicular to the base surface.This base surface of the optically clear adhesive preferably has an angle to the surface of the protective pane that is suitable for coupling IR radiation into the pane. The optically clear adhesive preferably has a refractive index that differs by less than 0.1, preferably less than 0.05, from the refractive index of the protective pane. As a result, the IR radiation is refracted less strongly at the interface between the optically clear adhesive and the pane. Nevertheless, any existing radiation refraction between the optically clear adhesive and the pane can be taken into account when selecting the angle of the base surface to the surface of the protective pane. In the context of the present invention, refractive indices are generally given based on a wavelength of 1500 nm. Methods for determining refractive indices are known to those skilled in the art.The refractive indices specified in the context of the invention can be determined, for example, by ellipsometry, using commercially available ellipsometers. Unless otherwise stated, the specification of layer thicknesses refers to the geometric thickness of a layer.

[0039] In a fourth embodiment of the invention, which can be combined with the first to third embodiments, the side camera also comprises a moisture detector, for example an IR sensor, for detecting water on the outer surface of the protective pane, and a control unit. The moisture detector is preferably configured such that it sends a signal to the control unit when water is present on the heating area of ​​the outer surface of the protective pane that is irradiated by the radiation source during operation. If the radiation source irradiates an area of ​​the protective pane that extends beyond the heating area, the moisture detector can be configured analogously to also check this area beyond the heating area for water deposits, i.e. to send a signal to the control unit when water is present on the area irradiated by the radiation source.The control unit is configured to electronically control the radiation source, at least upon receipt of the signal, so that the radiation source emits IR radiation according to the invention and thus removes at least moisture in the heating area of ​​the protective screen. This offers the advantage that the radiation source is only active when water is also deposited on the protective screen, which can significantly reduce the energy consumption of the radiation source. The moisture detector is preferably attached to the protective screen or the housing of the side camera so that it can effectively detect condensed water or frost on the outer surface of the protective screen.

[0040] The first embodiment can be combined with the second or third embodiment. Furthermore, the invention also encompasses the combination of the first embodiment with the second and fourth embodiments, as well as the combination of the first embodiment with the third and fourth embodiments.

[0041] Furthermore, the invention extends to a vehicle comprising at least one side camera according to the invention, preferably at least two side cameras according to the invention, in particular exactly two side cameras according to the invention. The side cameras can be used as a replacement for the vehicle's side mirrors; however, it is also possible to use the side cameras in addition to a side mirror on the vehicle. For example, it is conceivable that the vehicle's side camera(s) are each mounted on a side mirror.

[0042] In a preferred embodiment, the side camera is mounted outside the vehicle interior on the vehicle's outer skin. This has the advantage that the camera can better film traffic. The "outer skin of the vehicle" refers to the primary visible surfaces of a vehicle, such as the doors and tailgates, as well as the roof, fenders, hood, bumper, and side panels.

[0043] The camera is therefore preferably a video camera that takes pictures and transmits them to an on-board computer (wirelessly or via cable). The on-board computer can, for example, display the images recorded by the camera on a display in the vehicle interior, giving the driver an overview of the traffic (behind). This makes it easier to avoid blind spots and, depending on the position of the display, the driver hardly or not at all needs to take their eyes off the road. The images recorded by the camera can also be saved on the on-board computer or another data storage unit if necessary, which can be particularly helpful in investigating traffic accidents. Preferably, however, the images are transmitted to the display in the vehicle interior and shown there, at least in real time.

[0044] The vehicle can be, for example, a passenger car, a truck, a motor vehicle, a tractor, or a bus. The vehicle is preferably a passenger car. The vehicle can be equipped with an internal combustion engine, comprising, for example, a gasoline engine or a diesel engine, an electric drive comprising a fuel cell and / or a rechargeable battery, or a hybrid drive. Hybrid drives and electric drives are particularly suitable because the radiation source is electrically operated. Such drive types must be energy-efficient; otherwise, the range of the vehicle is significantly reduced, thus making the advantages of the vehicle according to the invention particularly clear.

[0045] The invention also extends to a method for removing moisture using the side camera according to the invention. "Moisture" in the context of the invention refers to water in a liquid or frozen state. The method comprises the following steps in the order mentioned:

[0046] (A) Activation of the radiation source and

[0047] (B) Emitting IR radiation from the radiation source so that at least the outer surface of the protective pane in the heating area is freed of water by means of the IR radiation.

[0048] In a preferred embodiment of the method according to the invention, the radiation source is activated at least upon detection of water on the heating region of the outside surface by a moisture detector. Method step B is then carried out. The vehicle preferably comprises a moisture detector and a control unit according to the fourth embodiment of the invention, such that upon detection of water by the moisture detector, a signal is sent to the control unit and the control unit controls the radiation source such that it is activated according to the method and then step B of the method is carried out. Particularly preferably, step B of the method according to the invention is ended and the radiation source deactivated when the moisture detector no longer detects any water on the outside surface, at least in the heating region.The radiation source therefore only irradiates the protective screen when the moisture detector detects water. In addition to or independently of this embodiment, the process can also be started and stopped manually, for example, by a vehicle occupant.

[0049] The various embodiments of the invention can be implemented individually or in any combination. In particular, the aforementioned features can be used not only in the specified combinations, but also in other combinations or on their own, unless they are explicitly described and described as alternatives to one another, without departing from the scope of the present invention.

[0050] The invention is explained in more detail below using exemplary embodiments, with reference to the accompanying figures. They show, in simplified form and not to scale:

[0051] Figure 1 A shows the rear of an embodiment of a vehicle according to the invention with an embodiment of a side camera according to the invention,

[0052] Figure 1B Top view of a vehicle door of the vehicle from Figure 1A, Figure 1C Side camera from Figure 1A in top view of the protective screen,

[0053] Figure 1 D Cross-sectional view of the side camera from Figure 1 C,

[0054] Figure 2A alternative design of a side camera in plan view of the side camera,

[0055] Figure 2B Cross-sectional view of the side camera from Figure 2A,

[0056] Figures 3-5 show further alternative designs of the side camera in cross-sectional views and

[0057] Figure 6 shows an absorption spectrum of water (liquid state).

[0058] Figures 1A, 1B, 1C and 1D each show different aspects of an embodiment of the vehicle 101 according to the invention and of the side camera 100 according to the invention. Figure 1A shows the rear of the vehicle 101 with a view of the trunk and rear window. The vehicle 101 is a passenger car of the sedan type, whereby the invention is not restricted to specific types and types of vehicles. Figure 1B shows a vehicle door of the vehicle 101 in a plan view and the side camera 100 in a side view with a view of the housing 1. Figure 1C shows the side camera 100 of the vehicle 101 in an enlarged view and in a plan view of the protective window 3 of the side camera 100. Figure 1D shows a cross-sectional view of the side camera 100 without the housing 1, whereby the cross section is indicated in Figure 1C by a section line (XX').

[0059] In addition to a first side camera 100, the vehicle 101 also includes a second side camera 100, which is attached to the opposite vehicle door. The side cameras 100 are constructed identically, so it is sufficient to describe the side cameras 100 using the side camera 100 on the right vehicle door (on the right, looking at the rear of the vehicle 101, see Figure 1A). Only the side camera 100 shown in Figures 1B, 1C, and 1D will be described below.

[0060] The side camera 100, as shown in Figures 1B, 1C and 1D, comprises a housing 1, for example made of plastic and / or metal. The housing 1 of the side camera 100 has an opening O into which a protective screen 3 is inserted. The protective screen 3 thus separates a housing interior R from the external environment U. The protective screen 3 is, for example, a soda-lime glass pane with a thickness of 1 mm. A camera 2, for example a video camera, is arranged centrally in the housing interior R, the camera lens of which is directed onto the interior-side surface II of the protective screen 3. The camera 2 is thus suitably arranged in the housing 1 to film the traffic in the external environment U. The area of ​​the protective screen 3 through which the camera 2 films the traffic (camera field of view) is indicated by the heating area P in Figure 1D.The visible light passes through this heating area P, which is received by the lens of the camera 2 and which is converted into virtual images (a film).

[0061] In addition to the camera 2, a radiation source 4 for IR radiation 5 in the wavelength range from 1.3 pm to 3.5 pm is also arranged in the housing interior R. The radiation source 4 is, for example, a fiber-bulk hybrid laser. The radiation source 4 is arranged such that it irradiates the interior-side surface II in the heating region P of the protective screen 3 directly with IR radiation 5 in the wavelength range from 1.3 pm to 3.5 pm. A scattering element 7 is arranged between the protective screen 3 and the radiation source 4, such that the IR radiation 5 from the radiation source 4 is scattered by the scattering element 7 before it appears on the protective screen 3. The scattering element 7 is, for example, an optical concave lens. However, the radiation source 4 can also be arranged and designed such that it can irradiate other areas of the protective screen 3.The IR radiation 5 transmits through the protective pane 3 in the heating area P and exits again on the outer surface I. The irradiation 5 can effectively remove the aqueous coating 6 on the protective pane 3 in the heating area P.

[0062] Reference is now made to Figures 2A, 2B and Figures 3 to 5. The variants of the side camera 100 shown in Figures 2A and 2B as well as Figures 3 to 5 essentially correspond to the variant from Figures 1A to 1D, so that only the differences are discussed here and otherwise reference is made to the description of Figures 1A to 1D.

[0063] Figure 2A shows the side camera 100 in an enlarged view and in a plan view of the protective screen 3 of the side camera 100. Figure 2B shows a cross-sectional view of the side camera 100 without the housing 1, wherein the cross section in Figure 2A is indicated by a section line (YY').

[0064] The variant of the side camera 100 shown in Figures 2A and 2B differs from that of Figures 1B to 1C in that the radiation source 4 is arranged along the entire circumferential side edge S of the protective screen 3. The radiation source 4 is arranged relative to the protective screen 3 such that the IR radiation 5 is coupled into the protective screen 3 via the edge surface of the side edge S. A scattering element 7, as in the variant from Figures 1B to 1D, can therefore be dispensed with here. The protective screen 3 guides the IR radiation 5 using the effect of total internal reflection until the radiation 5 strikes a spot fogged with water 6. Due to the different refractive indices between the protective screen 3 and the water 6, the IR radiation 5 couples out into the water 6, causing it to heat up and evaporate.Due to the band-like distribution of the radiation source 4 around the entire circumferential side edge S of the protective pane 3, the coupled IR radiation 5 has a high intensity over the entire surface of the protective pane 3.

[0065] The side camera 100 also includes a moisture detector 9, which is attached to the camera 2 in the housing interior R. However, the moisture detector 9 can also be arranged at a different location on the side camera 100, for example, outside the housing interior R, exposed to the external environment U. The moisture detector 9 is, for example, an IR sensor and is connected to a control unit (not shown). The moisture detector 9 detects watery coating and / or frost 6 in the heating area P of the protective pane 3. As soon as the detector 9 detects water 6, it transmits a signal to the control unit, which then controls the radiation source 4, so that the radiation source 4 couples IR radiation 5 into the protective pane 3. Other embodiments of the side camera 100 can also be equipped with a moisture detector 9 as described here.In particular, the embodiments of Figures 1A to 1D and Figures 3 to 5 preferably also comprise a moisture detector 9 and a control unit connected thereto.

[0066] The side camera 100 of Figure 3 differs from the design of Figures 2A and 2B in that the radiation source 4 couples the IR radiation 5 not via the circumferential side edge S, but via an inner edge surface of a recess A in the protective screen 3. The recess A is designed in the form of a blind bore, although a feedthrough is also possible. The radiation source 4 is arranged in the recess A and radiates the IR radiation 5 via the edge surface of the recess A in the direction of the heating area P. The advantage here is that the distance between the heating area P and the radiation source 4 is shorter, which means that the density of the IR radiation 5 can be lower, and the radiation source 4 can therefore be less powerful. In Figure 4, the IR radiation 5 of the radiation source 4 is coupled in via an IR mirror layer 8, which is arranged on the outer surface I of the protective screen 3 outside the heating area P.For this purpose, the radiation source 4 is applied, preferably glued, to the interior-side surface II of the protective pane 3 opposite the IR reflective layer 8. The IR radiation 5 from the radiation source 4 enters the protective pane 3 via the interior-side surface II and is transmitted through it. It exits at the exterior surface I in the area of ​​the IR reflective layer 8 and is reflected back to the protective pane 3 by the IR reflective layer 8 at an angle suitable for coupling. The IR radiation 5 is then guided through the protective pane 3 until it strikes a point provided with a water coating 6, where it is coupled out. The protective pane 3 is mechanically processed in the area of ​​the IR reflective layer 8, for example by sandblasting, so that this area has inclined surfaces compared to the interior-side surface II of the protective pane 3.This inclination allows the IR radiation 5 to be reflected at an angle that is particularly advantageous for coupling. Alternatively, instead of these inclined surfaces, a microprismatic film could be used, which is applied to the outer surface I and whose inclined surfaces are provided with an IR mirror layer 8 on the surface facing away from the protective screen 3. The IR mirror layer 8 is, for example, a single-layer or multi-layer silver layer.

[0067] The radiation source 4 of the embodiment from Figure 5 is also applied to the interior-side surface II of the protective pane 3 outside the heating region P. The radiation source 4 is fixed to the protective pane 3, for example, by means of an angling device 10, which essentially consists of an optically clear acrylate-based adhesive or is filled with such an adhesive. The device 10 essentially forms an oblique wedge, the base surface of which is arranged at a 90° angle to the emission surface of the radiation source 4. The base surface of the device is arranged at an angle of less than 90° to the interior-side surface II of the protective pane 3, which is suitable for coupling IR radiation 5 into the protective pane 3.This means that the IR radiation 5 emitted by the radiation source 4 is first transmitted through the optically clear adhesive and then strikes the interior-side surface II of the protective screen 3 at an angle suitable for coupling. The IR radiation 5 is then guided through the protective screen 3 until it strikes a point covered with water 6, where it is coupled out. The advantage of this variant is its uncomplicated effort, which simplifies the retrofitting of existing side-view camera systems and also makes subsequent repair of such systems easier. Figure 6 shows an absorption spectrum of water in the liquid state. The diagram shows that water molecules, for example, have a particularly high absorption coefficient at a wavelength of approximately 3 pm.In a preferred embodiment of the side camera, a radiation source in the IR wavelength range from A = 2.5 pm to A = 3.3, particularly preferably from A = 2.9 to A = 3.1 pm, is therefore used for the protective screen, since in this preferred wavelength range the absorption and excitation of the water molecules and thus the resulting heating and evaporation is particularly high.

[0068] List of reference symbols

[0069] 1 housing

[0070] 2 cameras

[0071] 3 protective screen

[0072] 4 Radiation source for IR radiation 5

[0073] 5 IR radiation

[0074] 6 Water

[0075] 7 Dispersal element

[0076] 8 IR mirror layer

[0077] 9 Moisture detector

[0078] 10 Device for angling

[0079] 100 side camera

[0080] 101 vehicle

[0081] A Recess in the protective screen 3

[0082] O Opening in the housing 1

[0083] P Heating area

[0084] S circumferential side edge of the protective screen 3

[0085] R Housing interior

[0086] U External environment

[0087] I outer surface of the protective screen 3

[0088] 11 interior surface of the protective screen 3

[0089] X— X' section line through the side camera 100 of Figure 1C

[0090] YY' section line through the side camera 100 of Figure 2A

Claims

Patent claims 1. A side-facing camera (100) for a vehicle (101), comprising a housing (1) with a housing interior (R) and a housing opening (O), a camera (2), and a protective screen (3) which is arranged in the housing opening (O) and which has an interior surface (II) facing the housing interior (R) and an exterior surface (I) facing away from the housing interior (R), wherein the camera (2) is arranged in the housing interior (R) and is directed towards the protective screen (3) so that it can record images through the protective screen (3), wherein the protective screen (3) is made of transparent glass, characterized in that a radiation source (4) for IR radiation (5) in the IR wavelength range from 1.3 pm to 3.5 pm is arranged relative to the protective screen (3) in such a way that the exterior surface (I) can be freed of water (6) at least in a heating region (P) by means of IR radiation (5) from the radiation source (4).

2. Side camera (100) according to claim 1, wherein the radiation source (4) comprises at least one LED and / or a laser.

3. Side camera (100) according to claim 1 or 2, wherein the radiation source (4) comprises at least one fiber-bulk hybrid laser, preferably with the laser medium Cr:ZnSe / S.

4. Side camera (100) according to one of claims 1 to 3, wherein the radiation source (4) can emit IR radiation (5) in the IR wavelength range from 1.8 pm to 3.4 pm, preferably from 1.9 pm to 3 pm.

5. Side camera (100) according to one of claims 1 to 4, wherein the radiation source (4) is arranged in the housing interior (R) such that it irradiates the interior-side surface (II) of the protective screen (3) during operation at least in the heating region (P).

6. Side camera (100) according to claim 5, wherein at least one scattering element (7) for scattering the IR radiation (5) is arranged between the radiation source (4) and the protective screen (3).

7. Side camera (100) according to one of claims 1 to 4, wherein the radiation source (4) is arranged relative to the protective screen (3) in such a way that the IR radiation (5) emitted by the radiation source (4) is at least partially coupled into the protective screen (3).

8. Side camera (100) according to claim 7, wherein the radiation source (4) couples in the IR radiation (5) via an edge surface of the protective screen (3), wherein the edge surface is part of a side edge (S) surrounding the protective screen (3) or part of an inner edge which is formed by a recess (A) made in the protective screen (3).

9. Side camera (100) according to claim 7, wherein an IR mirror layer (8), preferably in the form of a prism film, is arranged on a surface (1, 11) of the protective screen (3), and wherein the radiation source (4) is arranged relative to the IR mirror layer (8) in such a way that the IR radiation (5) emitted by the radiation source (4) is coupled into the protective screen (3) by means of reflection at the IR mirror layer (8).

10. Side camera (100) according to one of claims 1 to 9, wherein the protective pane (3) is a single-glazed pane made of soda-lime glass, borosilicate glass, quartz glass or aluminosilicate glass.

11. Side camera (100) according to one of claims 1 to 10, further comprising a moisture detector (9) and a control unit, wherein the moisture detector (9) is arranged such that it sends a signal to the control unit when water (6) is located on the heating area (P) of the outer surface (I) of the protective screen (3), wherein the control unit is configured such that, at least upon receipt of the signal, it electronically controls the radiation source (4) so ​​that the radiation source (4) switches into operation.

12. Vehicle (101) comprising a side camera (100) according to one of claims 1 to 11.

13. The vehicle (101) according to claim 12, wherein the side camera (100) is mounted outside the vehicle interior on the outer skin of the vehicle (101).

14. A method for removing moisture using a side camera (100) according to any one of claims 1 to 11, comprising the steps of: (A) Activation of the radiation source (4) and (B) Emitting IR radiation (5) from the radiation source (4) so ​​that at least the outer surface (I) of the protective screen (3) in the heating area (P) is heated by means of the IR Radiation (5) is freed from water (6).

15. The method according to claim 14, wherein the method steps (A) and (B) are carried out as a result of the detection of water (6) on the heating area (P) by a moisture detector (9) and the radiation source (4) is deactivated and thus the method is terminated when the moisture detector (9) does not detect any water (6) on the outside surface (I).

Images