Control unit for a darkening device with variable light transmission for a vehicle window, darkening system for a vehicle window, method for darkening a vehicle window and computer program product for darkening a vehicle window

Abstract

Control unit (10) for a darkening device (20) with variable light transmission for a vehicle window (1) comprising: • a first interface (11) to a first imaging sensor (2), which, when used in an interior (3) of a vehicle (4), is arranged for: ◯ detecting darkened areas in the interior (3) of the vehicle (4), wherein the darkened areas in the interior (3) are generated by the action of a light source (S1, S2) on a side of the darkening device (20) facing away from the interior (3) and by predefined darkened areas of the darkening device (20), and ◯ detecting the face of a vehicle occupant; • a processing unit (12) for evaluating data from the first imaging sensor (2) in order to: ◯ calculate a position of the light source (S1, S2) depending on the darkened areas in the interior (3), ◯ calculate the position of the eyes (A) of the vehicle occupant depending on the face.• to calculate, depending on the position of the light source (S1, S2) and the position of the vehicle occupant's eyes (A), areas of the blackout device (20) to be darkened so that the vehicle occupant's view is unobstructed by the light source (S1, S2), and • to determine a signal for controlling the areas to be darkened, and • a second interface (13) to the blackout device (20) to control the blackout device (20) with the signal.

Description

[0001] The invention relates to a control unit for a darkening device with variable light transmission for a vehicle window. Furthermore, the invention relates to a darkening system for a vehicle window. The invention also relates to a method for darkening a vehicle window. Finally, the invention relates to a computer program for darkening a vehicle window.

[0002] Electrochromic glass is known from the prior art for partially or completely darkening vehicle windows to prevent an external light source from interfering with a driver's vision while driving. For example, US patent 4,892,394 discloses an electronic sunshade. However, this sunshade must be controlled manually or using a complex electronic compass.

[0003] This is where the invention comes in. The invention is based on the objective of providing a simple control system for darkening devices for vehicle windows, taking into account, in particular, light sources other than sunlight.

[0004] The control unit according to the invention solves the problem by controlling a darkening device with variable light transmission for a vehicle window. The control unit comprises a first interface to a first imaging sensor. The first imaging sensor is arranged in the interior of a vehicle. The first imaging sensor detects darkened areas in the vehicle interior. The darkened areas in the interior are created by the action of a light source on a side of the darkening device facing away from the interior and by predefined darkened areas of the darkening device. The first imaging sensor also detects the face of a vehicle occupant. The control unit further comprises a processing unit. The processing unit evaluates data from the first imaging sensor. The processing unit calculates the position of the light source based on the darkened areas in the interior.The processing unit further calculates the position of the vehicle occupant's eyes based on their facial features. The processing unit also calculates, based on the position of the light source and the position of the vehicle occupant's eyes, the areas of the blackout device that need to be darkened so that the vehicle occupant's vision is not obstructed by the light source. The processing unit also generates a signal to control the areas to be darkened. The control unit further includes a second interface. This second interface is an interface to the blackout device, enabling it to be controlled with the signal. The invention thus advantageously enables the automatic detection of a light source that dazzles a vehicle occupant or otherwise obstructs their vision, and the automatic control of a blackout device to prevent glare.This can prevent traffic accidents caused by dimming headlights. This increases driving safety.

[0005] A control unit prepares sensor data as input signals, processes them using a computing unit, such as a processor, and provides logic and / or power levels as control signals. Actuators are controlled and regulated using these control signals. The control unit is connected to the first imaging sensor and, according to one aspect of the invention, to the second imaging sensor via the first and third interfaces. The first and / or third interfaces are, for example, each a component. Data exchange occurs via wired or wireless technology, such as radio technology. The control unit is preferably integrated into the vehicle's electrical system. In particular, the control unit is an electronic control unit that controls several devices of a vehicle system, i.e., a vehicle domain.In this context, the control unit is called a domain electronic control unit, abbreviated domain ECU. Preferably, the control unit is an ADAS / AD domain ECU, that is, a control unit for assisted or autonomous driving.

[0006] An interface is a component between at least two functional units where logical quantities, such as data, or physical quantities, such as electrical signals, are exchanged, either unidirectionally or bidirectionally. This exchange can be analog or digital and can be wired or wireless. For example, an interface could be a wired interface or a WLAN interface.

[0007] A blackout device serves as protection against external light sources, for example, as sun protection or as protection against the low beams of oncoming traffic. Furthermore, the blackout device provides privacy. Due to its adjustable light transmission, the blackout device can be set to transparent, translucent, or opaque, for example, by applying an electrical voltage. The blackout device is, for example, designed as a film that can be attached to the inside of the vehicle window. For instance, the blackout device can be retrofitted to the vehicle window with adhesive. Alternatively, the blackout device is already integrated into the vehicle window. The blackout device is typically arranged flush with the inside of the vehicle window. This minimizes reflections trapped between the individual layers.

[0008] The blackout device comprises areas that can be controlled individually and independently of other areas of the blackout device. This allows, for example, the darkening of areas illuminated by the light of an oncoming vehicle. The blackout device can thus be adapted to the specific points of light impact. Preferably, the blackout device comprises grid-shaped areas that can be controlled individually and independently of one another. According to one aspect of the invention, the degree of blackout of the blackout device depends on the signal strength. With a relatively weak signal, the respective areas are only slightly dimmed; with a relatively strong signal, the respective areas are completely darkened so that no light passes through them.

[0009] The darkened areas in the interior are created by shadows cast by the darkened areas of the blackout device, for example, shadows cast on the seat surface or floor in the interior.

[0010] Vehicles are land vehicles, watercraft, and / or aircraft. Vehicle windows are panes that allow a vehicle occupant to see out of the vehicle and protect them from wind, precipitation, and airborne particles. Vehicle windows are made of materials such as glass or plastic.

[0011] An imaging sensor is a sensor that generates an image using an imaging technique. For example, an image sensor in a camera, a pixel sensor in a lidar or radar system, or an ultrasonic sensor is an imaging sensor. Intrinsic and extrinsic parameters of the imaging system are used to calculate the position of the light source and the position of the vehicle occupant's eyes. The first imaging sensor is preferably an imaging sensor in a camera for interior monitoring, such as a 2D or 3D camera. The camera is, for example, an infrared camera. With an infrared camera, eyes are detected as bright points.

[0012] A vehicle occupant is a driver, a passenger, or any other person inside the vehicle.

[0013] The light source is light from oncoming traffic, particularly during night driving, or the sun. According to a further aspect of the invention, a threshold value for the intensity of the light from the light source is defined, above which the darkening device is activated.

[0014] Electronic circuits with logic components are examples of a processing unit. A processor is another example. The processing unit provides the computing power to process the data from the imaging sensor, along with the darkened areas in the vehicle interior and the position of the vehicle occupant's eyes, in real time. For example, the processing unit might include a multi-processor core with multiple CPUs and / or GPUs. The position of the light source is calculated, for instance, using projective transformations of the darkened areas in the vehicle interior. For example, three predefined areas of the blackout device are dimmed, and the resulting darkened areas in the interior due to the effect of the light source are measured. Based on these darkened areas, the position of the light source can be determined using a projective transformation.

[0015] According to one aspect of the invention, the control unit includes a third interface to a second imaging sensor. When used, the second imaging sensor is located on the exterior of the vehicle. The second imaging sensor detects the light source. The processing unit is configured to evaluate the data from the first imaging sensor to calculate the position of the vehicle occupant's eyes. The processing unit is further configured to evaluate the data from the second imaging sensor to calculate the position of the light source. The processing unit thus processes the image obtained from the second imaging sensor to define a brightness intensity and to locate the light source. By processing the image from the first imaging sensor, the processing unit defines the position of the vehicle occupant's eyes.Depending on the brightness intensity and the position of the vehicle occupant's eyes—that is, their gaze direction or view—the processing unit determines whether the occupant's view is obstructed by the light source, i.e., whether they are being blinded. Furthermore, the processing unit determines the trajectories of the light rays from the light source and defines the areas of the blinding device that must be darkened to prevent the vehicle occupant from being disturbed by the light source.

[0016] According to another aspect of the invention, several first and second imaging sensors are provided to increase the accuracy in the localization of the light source and the eyes of the vehicle occupant.

[0017] The darkening system according to the invention for a vehicle window comprises a darkening device with variable light transmission. The darkening system further comprises at least one first imaging sensor. The first imaging sensor can be arranged in the interior of a vehicle. The darkening system also comprises a control unit according to the invention. The darkening system is integrated into the vehicle or can be retrofitted.

[0018] According to another aspect of the invention, the blackout system comprises a second imaging sensor. The second imaging sensor can be arranged on the outside of the vehicle.

[0019] According to another aspect of the invention, the blackout device is congruent with the vehicle window. The blackout device can be attached to the vehicle window or is integrated into the vehicle window.

[0020] According to another aspect of the invention, the darkening device comprises an electrochromic or thermochromic material or individually controllable liquid crystal cells.

[0021] Electrochromic materials change their light transmission depending on an applied DC voltage. Thermochromic materials change their light transmission depending on the temperature.

[0022] A liquid crystal, abbreviated LC, is an anisotropic fluid, meaning it exhibits different propagation speeds in different directions depending on the polarization of incident light. Due to this anisotropy, liquid crystals influence the polarization direction of light waves. A wave is polarized if its displacement has a specific orientation relative to its propagation speed. A wave is linearly polarized if its displacement only follows a direction perpendicular to its propagation direction. In a circularly polarized wave, the polarization direction follows a circle. All polarization directions occur alternately in a circularly polarized wave.

[0023] A liquid crystal cell comprises a liquid crystal and means for applying an electrical voltage to control atoms or molecules of the liquid crystal. The electrical voltage can result from an electric or a magnetic field. The field can be a static or an alternating field. Atoms or molecules of liquid crystals typically have a rod- or disk-shaped form. A liquid crystal cell comprises, for example, two plates, the structure of each plate surface having a preferred orientation. For example, the liquid crystal cell comprises two plates, each provided with parallel grooves, the directions of the grooves in the plates being rotated by 90° relative to each other. Preferably, both plates are transparent. Particularly preferably, both plates are made of glass. The plates include connecting leads for applying an electrical voltage to the plates.For example, the outer surfaces of the glass plates are each coated with an electrode layer with connecting leads for controlling the liquid crystal cell. The liquid crystal is arranged between the glass plates.

[0024] The liquid crystal preferably comprises a nematic compound. A nematic compound has the property that, when a field is applied, its components align themselves in the direction of the field. This arrangement corresponds to a parallel-plate capacitor whose dielectric is the liquid crystal cell. Due to the 90° rotation of the groove directions in the glass plates, the atoms or molecules of the liquid crystal arrange themselves helically. This helical structure can also be induced by the addition of cholesteric compounds. Cholesteric compounds exhibit a nematic order with a continuously rotating preferred orientation. The liquid crystal cell is arranged between two polarizing filters, also rotated by 90°. A transmission axis of the first polarizing filter runs parallel to the direction of the grooves in the first glass plate.One transmission axis of the second polarizing filter runs parallel to the direction of the grooves on the second glass plate. The first polarizing filter thus corresponds to a polarizer. The second polarizing filter thus corresponds to an analyzer. When no voltage is applied, incident light is rotated by 90° and passes through the liquid crystal. When a voltage is applied, the atoms or molecules of the liquid crystal align themselves perpendicular to the electrode surfaces. Incident light passes through the liquid crystal without rotation. Due to the 90° rotation of the polarizing filters, incident light is absorbed. This example of a liquid crystal cell corresponds to the light control cell disclosed in CH 532 261.

[0025] The liquid crystal cells are advantageously designed to be so large that a single liquid crystal cell or a group of five adjacent liquid crystal cells corresponds to the image-side size of the sun.

[0026] According to another aspect of the invention, the darkening system is used for a windshield, rear window, side window, the lens of an exterior and / or interior mirror and / or a roof window.

[0027] The method according to the invention darkens a vehicle window. Darkened areas in the interior of a vehicle are detected. Furthermore, the face of a vehicle occupant is detected. Based on the darkened areas in the interior, the position of a light source shining on the side of a darkening device facing away from the interior is calculated. Based on the face, the position of the vehicle occupant's eyes is calculated. Based on the position of the light source and the position of the vehicle occupant's eyes, areas of the darkening device are calculated that are to be darkened so that the vehicle occupant's view is not obstructed by the light source. Finally, a signal for controlling the areas to be darkened is determined. The darkening device is controlled by this signal.To carry out the method, a control unit or a darkening system according to the invention is used. The method is preferably carried out in an endless loop. That is, after a first pass, when the areas to be darkened are darkened, the brightness distribution on the vehicle windshield is determined again, either with the first imaging sensor by darkening predefined areas of the darkening device and detecting the darkened areas in the interior, or with the image from the second imaging sensor. This advantageously takes into account any change in the position of the light source due to the movement of the vehicle.

[0028] According to another aspect of the invention, the method is computer-implemented.

[0029] The computer program product according to the invention darkens a vehicle window. The computer program product comprises commands. The commands cause a control unit or a darkening system according to the invention to execute a method according to the invention when the program is running on the control unit.

[0030] The invention is explained by way of example in the following figures. They show: Fig. 1 an embodiment of a vehicle window without a darkening device according to the invention, Fig. 2 an embodiment of the vehicle window made of Fig. 1 with a darkening device according to the invention, Fig. 3 an embodiment of a blackout system according to the invention, Fig. 4 an embodiment of a control unit according to the invention, Fig. 5 an embodiment of a method according to the invention and Fig. 6 another embodiment of a method according to the invention.

[0031] In the figures, identical reference symbols denote identical or at least similar reference parts. For clarity, only the reference symbols relevant to the respective figure are given in each figure.

[0032] Fig. Figure 1 shows the view of a vehicle occupant through a vehicle window 1 a vehicle 4 The vehicle occupant is, for example, the driver. The vehicle window 1 is a front or windshield. The vehicle 4 For example, a car. 4 A foreign vehicle is approaching. The low beam headlights of the foreign vehicle are on. The low beam headlights are light sources. S1 The light from the light sources S1 hits the vehicle window 1 Without a blackout device according to the invention 20The vehicle occupant is affected by the light sources S1 blinded.

[0033] Fig. Figure 2 shows the view of the vehicle occupant through the vehicle window. 1 with attached blackout device 20 . Regarding the blackout device 20 The areas that are darkened are precisely those on which the light from the light sources falls. S1 This ensures that the vehicle occupant is not blinded.

[0034] Fig. Figure 3 shows a blackout system 30 The blackout system 30 The blackout device includes 20 Furthermore, the blackout system includes 30 a first imaging sensor 2 The first imaging sensor 2 This is, for example, an imaging sensor of an interior camera. Using images from the first imaging sensor. 2 calculates a unit of calculation 12 a control unit 10 Position of eyes Aof the vehicle occupant. The blackout system also includes, for example, a second imaging sensor. 5 The second imaging sensor 5 For example, an outdoor camera. Using images from the second imaging sensor. 5 The processing unit calculates the position of the light sources. S1 or a position of a light source S2 , for example the sun.

[0035] The control unit 10 is in Fig. 4 shown. The control unit 10 includes a first interface 11 to the first imaging sensor 2 The control unit 10 It also includes a third interface 14 to the second imaging sensor 5 The control unit 10 It also includes the computing unit 12 The processing unit calculates a signal for the targeted control of the blackout device. 20 The control unit 10includes a second interface 13 . Via the second interface 13 For example, grid cells 21 the blackout device 20 targeted.

[0036] Alternatively, only the first imaging sensor is available. 2 intended, from whose recordings the position of the light sources could be determined S1 or S2 calculated without relying on a second imaging sensor 5 to be dependent. However, the second imaging sensor 5 the accuracy of the blackout system 30 increased.

[0037] Fig. Figure 5 shows the inventive method with only the first imaging sensor. Fig. Figure 6 shows an alternative using the first imaging sensor. 2 and the second imaging sensor 5 Both processes are carried out as an endless loop. Reference symbol list 1 vehicle window 2 first imaging sensor 3 Interior 4 vehicles 5 second imaging sensor 10 Control unit 11 first interface 12 computing units 13 second interface 14 third interface 20 blackout device 21 Grid cell 30 blackout system S1 Light source S2 light source A eye QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 4892394

[0002] CH 532261

[0024]

Claims

[1] Control unit (10) for a darkening device (20) with variable light transmission for a vehicle window (1) comprising • a first interface (11) to a first imaging sensor (2), which is arranged in an interior (3) of a vehicle (4) when used o for detecting darkened areas in the interior (3) of the vehicle (4), wherein the darkened areas in the interior (3) are created by the action of a light source (S1, S2) on a side of the darkening device (20) facing away from the interior (3) and by predefined darkened areas of the darkening device (20), and ◯ to capture the face of a vehicle occupant, • a computing unit (12) for evaluating data from the first imaging sensor (2) to ◯ to calculate a position of the light source (S1, S2) depending on the darkened areas in the interior (3), ◯ to calculate the position of the eyes (A) of the vehicle occupant depending on the face, ◯ Depending on the position of the light source (S1, S2) and the position of the eyes (A) of the vehicle occupant, calculate areas of the darkening device (20) that are to be darkened so that the view of the vehicle occupant is undisturbed due to the light source (S1, S2) and ◯ to determine a signal for controlling the areas to be darkened, and • a second interface (13) to the blackout device (20) to control the blackout device (20) with the signal. [2] Control unit (10) according to claim 1, comprising a third interface (14) to a second imaging sensor (5), which when used on an outside of the vehicle (4) is arranged for detecting the light source (S1, S2), wherein the computing unit (12) is configured • the data from the first imaging sensor (2) to calculate the position of the eyes (A) of the vehicle occupant and • to evaluate the data from the second imaging sensor (5) to calculate the position of the light source (S1, S2). [3] Darkening system (30) for a vehicle window (1) comprising • a blackout device (20) with variable light transmission, • at least one first imaging sensor (2) can be arranged in an interior (3) of a vehicle (4) and • a control unit (10) according to claim 1 or 2. [4] Darkening system (30) according to claim 3 comprising a second imaging sensor (5) arrangable on an outside of the vehicle (4). [5] Blackout system (30) according to claim 3 or 4, wherein the blackout device (20) is congruent with the vehicle window (1) and can be attached to the vehicle window (1) or is integrated into the vehicle window (1). [6] Darkening system (30) according to one of claims 3 to 5, wherein the darkening device (20) comprises an electrochromic or thermochromic material or individually controllable liquid crystal cells. [7] Blackout system (30) according to any one of claims 3 to 6, wherein the blackout system (30) is used for a windshield, rear window, side window, lens of an external and / or internal mirror and / or a roof window. [8] Method for darkening a vehicle window (1) comprising the steps • Detection of darkened areas in the interior (3) of a vehicle (4) • Capturing the face of a vehicle occupant, • Calculating the position of a light source (S1, S2) acting on a side of a blackout device (20) facing away from the interior (3) as a function of the darkened areas in the interior (3), • Calculating the position of the vehicle occupant's eyes (A) depending on the face, • Depending on the position of the light source (S1, S2) and the position of the vehicle occupant's eyes (A), calculate areas of the darkening device (20) that are to be darkened so that the vehicle occupant's view through the light source (S1, S2) is undisturbed, • Determining a signal to control the areas to be darkened and • Controlling the blackout device (20) with the signal, wherein a control unit (10) according to claim 1 or 2 or a blackout system (30) according to one of claims 3 to 7 is used to carry out the method. [9] The method of claim 8, wherein the method is computer-implemented. [10] Computer program product for darkening a vehicle window (1) comprising commands that cause a control unit (10) according to claim 1 or 2 or a darkening system (30) according to any one of claims 3 to 7 to execute a method according to claim 8 or 9 when the program is running on the control unit (10).

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