Patent Description:
In a known vehicle, one or more sensors for detecting a position of the sun relative to the vehicle are provided for operating a dimmable wind shield to prevent glare. Light-intensity sensors are known for controlling an HVAC system in response to radiative energy supplied by the light.

The known sensors are commonly arranged at or near the wind shield or side windows, depending on the intended function. In particular for preventing glare, the known sensor is arranged at the wind shield to accurately determine a direction of the excessive-light source, usually the sun, relative to the eyes of the driver. Moreover, only a part of the surroundings in front of the vehicle needs to be in a field of detection as a sun position rearward of the vehicle will never blind the driver.

For HVAC control, the position of the sensor is less critical and may be provided at many positions without requiring high positional and orientational accuracy. In a known embodiment, the sensors are configured to determine a main direction from which any light is mainly incident to be able to differentiate in air cooling and heating in different HVAC zones in the vehicle. Also in such embodiment, high accuracy is not required.

In recent years, vehicles have been provided with more and more sensors. In particular, autonomous driving capabilities have been introduced, requiring highly accurate and reliable sensor systems. Many of such sensor systems use electromagnetic radiation, either in a visible part of the electromagnetic spectrum or in an invisible part, like infrared or UV. Such sensor system may be sensitive to an excessive amount of exterior light, like sun light. Further, such sensor systems are not limited in their field of detection and thus may be configured to detect an external condition in any direction relative to the vehicle.

It is desirable to provide a roof assembly and a sensor system for use therein for detecting an intensity and direction of incident light suitable for multiple purposes, including for detecting potential interference of an excessive amount of exterior light with autonomous driving sensors.

A roof assembly for a vehicle comprising a roof mountable sensor system in accordance with the preamble of the main claim is known from <CIT>.

In a first aspect, a roof assembly in accordance with the main claim is provided. The sensor system of the roof assembly is configured to be mounted on a roof of a vehicle and the sensor system comprises a sensor unit. The sensor unit comprises an omnidirectional incident-light detector for detecting an incident-light intensity and an associated light-source position relative to the vehicle.

At the roof level, an incident-light sensor system is enabled to have a larger, omnidirectional field of detection. As a result, an output of the sensor system may be used for many different purposes, including but not limited to controlling a dimmable wind shield, controlling an HVAC system or adapting an output of another sensor system like an autonomous driving sensor.

As used herein, an omnidirectional field of detection is intended to refer to about a half sphere around the sensor unit. The sensor unit is thus configured to detect any position of at least the sun relative to the vehicle on the roof of which the sensor unit may be mounted. Depending on vehicle shape and vehicle dimensions and depending on sensor unit configuration and sensor unit design, the field of detection may a bit more or a bit less than a half sphere. Essentially, the sensor unit is configured to have a field of detection all around the vehicle.

Many incident-light detection systems are known in the prior art, including omnidirectional sensor units. A person skilled in the art is considered to be able to select a suitable sensor unit within the scope of the present invention. The selection may take into account vehicle design aspects, functional aspects and properties, including accuracy and reliability, weatherability, cost-effectiveness and many other considerations.

Aforementioned other sensor system may be integrated with the above-described sensor system. So, in an embodiment of the roof assembly, the sensor system comprises a first sensor unit and a second sensor unit. The first sensor unit comprises the omnidirectional incident-light detector and the second sensor unit is configured to detect an exterior condition, wherein an output of the second sensor unit is compensated for incident light as detected by the first sensor unit. For example, the second sensor unit may comprise a camera and in response to an output of the first sensor unit optical settings of the camera may be adapted such that glare by the incident light does not interfere with the autonomous driving function. Instead of adapting optical settings, a digital image obtained from such camera may be digitally processed to reduce any glare or overexposure-related artefacts. If no such compensation is available, e.g. for another type of sensor, the output of the first sensor unit can otherwise be used to ignore the output of the second sensor unit, if it is determined that an excessive amount of exterior light might affect reliability or accuracy of the output of the second sensor unit.

In an embodiment of the roof assembly, the sensor unit comprises a first light-sensitive subunit and a second light-sensitive subunit. The first and the second light-sensitive subunits are spaced apart and in different orientations such to be configured to detect incident light from different light-source positions. The sensor unit as used in the roof assembly may be embodied as a single unit or may be embodied in a number of subunits. For example, a subunit may be arranged at two or more edges or corners of a vehicle roof, wherein each subunit is oriented to have a dedicated field of detection to detect light incident from a predetermined part of the combined field of detection. Combining outputs from the number of subunits provides the sensor unit output corresponding to an omnidirectional field of detection.

In an embodiment of the roof assembly, the sensor unit is arranged at a highest location of the roof, when mounted on the vehicle. At the highest location of the roof, it may be expected that a maximum size of the field of detection is obtainable as a minimum number of objects may interfere in the field of detection.

In an embodiment, the transparent panel comprises a first section and a second section. The transparent panel comprises an omnidirectional sensor unit at the roof, the sensor unit is enabled to not only control a (locally) dimmable front wind shield, but is also enabled to control any dimmable side windows and a dimmable roof window.

In an embodiment, at a location where light passes through the transparent panel to the sensor unit, the transparent panel is provided with predetermined optical properties for adapting incident light rays to the sensor unit. The transparent panel may be shaped like a lens, or the like, or may be provided with any optical elements, like a lens, a Fresnel lens or a reflective element. Such shape or elements may be arranged at the interior surface or at the exterior surface, depending on the function. Such an optical system may assist in shaping the exterior light to be suitably projected on a light-sensitive element, e.g. a photo-detector that based on incident light changes its electrical properties, like its resistance or its output voltage or current.

In an embodiment, the sensor unit is moveably arranged and the sensor system comprises a control unit, wherein the control unit is configured to move the sensor unit. To increase a field of detection or to increase detection accuracy, for example, the sensor unit may be partially or completely moveable. The movement may be provided to adjust an orientation of the sensor unit. So, in a particular embodiment, the sensor unit may detect a strong light source and may then be moved to be oriented towards such light source in order to more accurately determine a light intensity, a position of the light source and may be even a size of the light source, for example. It is apparent to those skilled in the art that such a moveably arranged sensor unit may also be employed at any other position in the vehicle, other than the position at the roof.

Other embodiments may combine aspects of the above-mentioned embodiments.

In an aspect, a roof assembly for a vehicle is provided. The roof assembly comprises the roof mountable sensor system as above described. In a particular embodiment thereof, the roof assembly may comprise a moveable panel or closure member that may be selectively arranged over a roof opening. Additionally or alternatively, the roof assembly may comprise the transparent panel to allow ambient, exterior light like sun light to enter the passenger compartment of the vehicle.

In a particular embodiment, the sensor unit is mounted at the interior surface of the moveably arranged transparent panel and an output of the sensor unit is compensated for change in orientation of the sensor unit, when moved with the transparent pane. A moveably arranged closure member, comprising the transparent panel and the sensor unit, when moving to uncover or cover the roof opening in the vehicle roof, may slightly change its orientation relative to the remainder of the vehicle. Such change in orientation may significantly affect the output of the sensor unit due to a different angle of incidence of the exterior light. The change in orientation may be predetermined and the output may be compensated or corrected based on such predetermined change in orientation relative to the remainder of the vehicle. Optionally, the change in orientation may be determined in situ using a sensor like a gyroscopic sensor, for example, and the output of the sensor unit may then be corrected or compensated based on such detected change in orientation.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating embodiments of the invention, are given by way of illustration only, since various changes and modifications within the scope of the invention as defined in the appended claims will become apparent to those skilled in the art from this detailed description with reference to the appended schematical drawings, in which:.

The first and second roof openings 3a, 3b are provided in a frame <NUM> of the open roof assembly, having a middle beam <NUM> of the frame <NUM> between the openings 3a, 3b.

The second roof opening 3b is arranged under the fixed panel 2b such that light may enter a vehicle interior passenger compartment through the fixed panel 2b, presuming that the fixed panel 2b is a glass panel or a similarly transparent panel, for example made of a plastic material or any other suitable material. The second roof opening 3b with a transparent or translucent fixed panel 2b is optional and may be omitted in another embodiment of the open roof assembly.

<FIG> further illustrates a drive assembly having a first guide assembly 6a, a second guide assembly 6b, a first drive cable <NUM> and a second drive cable <NUM>. The first and second guide assemblies 6a, 6b are arranged on respective side ends SE of the moveable panel 2a and may each comprise a guide and a mechanism. The guide is coupled to the frame <NUM>, while the mechanism comprises moveable parts and is slideably moveable in the guide. The first and the second drive cables <NUM>, <NUM> are provided between the mechanisms of the respective guide assemblies 6a, 6b and an electric motor <NUM>.

The drive cables <NUM>, <NUM> couple the electric motor <NUM> to the mechanisms of the respective guide assemblies 6a, 6b such that upon operating the electric motor <NUM>, the mechanisms start to move. In particular, a core of the drive cable <NUM>, <NUM> is moved by the electric motor <NUM> such to push or pull on the mechanisms of the respective guides 6a, 6b. Such a drive assembly is well known in the art and is therefore not further elucidated herein. Still, any other suitable drive assembly may be employed as well without departing from the scope of the present invention. Moreover, in a particular embodiment, an electric motor may be operatively arranged between the respective guides and the respective mechanisms of the guide assemblies 6a, 6b and, in such embodiment, a drive assembly may be omitted completely.

In the illustrated embodiment, the electric motor <NUM> is mounted near or below the front end FE of the moveable panel 2a at a recess <NUM>. In another embodiment, the electric motor <NUM> may be positioned at any other suitable position or location. For example, the electric motor <NUM> may be arranged near or below the rear end RE of the moveable panel 2a or below the fixed panel 2b.

A control module <NUM> is schematically illustrated and is operatively coupled to the electric motor <NUM>. The control module <NUM> may be any kind of processing module, either a software controlled processing module or a dedicated processing module, like an ASIC, which are both well known to those skilled in the art. The control module <NUM> may be a stand-alone control module or it may be operatively connected to another control module, like a multipurpose, generic vehicle control module. In yet another embodiment, the control module <NUM> may be embedded in or be part of such a generic vehicle control module. Essentially, the control module <NUM> may be embodied by any control module suitable for, capable of and configured for performing operation of the electric motor <NUM> and thus the moveable roof assembly.

<FIG> shows an exemplary vehicle <NUM> comprising a roof panel, which may or may not be transparent, and an optional front header panel <NUM>. The roof panel <NUM> is provided with a sensor system <NUM>. The sensor system <NUM> is mounted on the vehicle roof and is configured to detect an intensity of exterior light and a direction of a light source, in particular in case the light source generates an excessive amount of light that may blind a driver or another sensor system, for example.

<FIG> shows the vehicle <NUM> comprising the sensor system <NUM> in an X-Z plane. The sensor system <NUM> has a field of detection DF, i.e. a field from which exterior light, like sun light, may be detected. The field of detection DF is essentially limited by the shape of the vehicle <NUM>. By mounting the sensor system <NUM> at the vehicle roof, it is enabled to have a large field of detection DF. Thus, the field of detection DF has a shape of a half circle in the X-Z plane.

By providing an omnidirectional sensor system <NUM>, it is enabled to detect a position of a light source at substantially any angle relative to the vehicle <NUM> as illustrated. Rays of light R1, R2, R3 under different angles of incidence in the X-Z plane are detectable by the sensor system <NUM>.

<FIG> shows the vehicle <NUM> comprising the sensor system <NUM> in an X-Y plane. The sensor system <NUM> has the field of detection DF, which corresponds to a full circle in the X-Y plane, enabling to detect rays of light R4 from any angle of incidence in the X-Y plane. Combined with the half circle field of detection DF in the X-Z plane as illustrated in <FIG>, the field of detection DF is formed as a half sphere. Of course, in particular in the X-Z plane, the exact positioning of the sensor system <NUM> and the shape of the vehicle <NUM> and any objects mounted thereon determines whether the field of detection DF is a complete half sphere or is a little more or a little less than a half sphere.

<FIG> shows an embodiment of the sensor system <NUM> mounted on and integrated in the roof of a vehicle comprising a roof panel <NUM> and in particular a transparent panel <NUM>. The transparent panel <NUM> comprises a first section <NUM> and a second section <NUM>.

The first section <NUM> is transparent and exterior light is enabled to pass through the transparent panel <NUM> into a passenger compartment of the vehicle.

The second section <NUM> is covered, usually but not necessarily at an interior side of the transparent roof panel <NUM>. Exterior light is blocked and cannot pass through the second section <NUM> to reach the passenger compartment. For example, an obscuration band formed with a coating, or the like, may be arranged on the roof panel <NUM> in the second section <NUM>. Alternatively or additionally, a headliner may be mounted at the interior side of the transparent roof panel <NUM>. In any case, a passenger in the passenger compartment cannot look through the second section <NUM> to the surroundings or sky. It may be preferred to mount the sensor system <NUM> in such a section, preventing a view on the sensor system <NUM>. In the embodiment of <FIG>, the sensor system <NUM> is indeed mounted in the second section <NUM>.

<FIG> show a number of embodiments of an omnidirectional light detecting sensor unit <NUM> for use in the sensor system <NUM>. <FIG> illustrate a first embodiment, wherein the sensor unit <NUM> comprises a number of light-sensitive elements <NUM> arranged in a <NUM> by <NUM> pattern and light-blocking or light-filtering separators <NUM> arranged between the light-sensitive elements <NUM>. The light-sensitive elements <NUM> and the separators <NUM> are arranged in an optional housing <NUM>.

The sensor unit <NUM> may be mounted on a transparent panel, e.g. a glass plate <NUM> having an interior surface <NUM>-i which is directed towards an interior of the vehicle and having an exterior surface <NUM>-e, which is opposite the interior surface <NUM>-i. The exterior surface <NUM>-e does not necessarily form an exterior surface of the vehicle, although it may be preferred to have the exterior surface <NUM>-e forming the exterior surface of the vehicle in order to have a large field of detection.

Due to the separators <NUM>, an amount of light detected by each light-sensitive element <NUM> is dependent on the angle of incidence of the light. For example, a first bundle of light rays B1 will result in a similar amount of light impinging on all light sensitive elements <NUM>, while a second bundle of rays B2, at a different angle of incidence than the first bundle of rays B1, will not only impinge on the light sensitive elements <NUM> but also on the separators <NUM>. As a result, the light-sensitive element <NUM> at a side from which the second bundle of rays B2 is coming will receive significantly more light than the other light-sensitive elements <NUM>. By comparison of an electrical output of each light-sensitive element <NUM>, it is enabled to detect a position of the light source from which the light rays originate and an overall light intensity can be determined.

<FIG> illustrates a second embodiment, wherein the sensor unit <NUM> is arranged in a hole in the transparent panel <NUM>. The sensor unit <NUM> is provided with a curved top surface <NUM> to enable light rays coming from aside to enter the sensor unit <NUM>, thus improving the field of detection.

The curved top surface <NUM> may additionally have a varying thickness to form a lens, for example. Such a lens may be advantageous to further improve sensitivity to light to increase an accuracy or to further increase a field of detection.

<FIG> schematically illustrates a third embodiment, wherein the sensor unit <NUM> is moveably arranged on a hingable support <NUM>. The hingeable support <NUM> may be operatively coupled to a control unit (not shown) for moving the sensor unit <NUM>. For example, based on the light as detected, the sensor unit <NUM> may be moved into an orientation or to a position in which a smaller angle of incidence between a bundle of light rays B2 and the sensor unit <NUM> is achieved. An angle α between the sensor unit <NUM> and a plane of the vehicle roof, for example, is then taken into account to determine a position of a light source from which the bundle of light rays B2 originates.

<FIG> shows another, fourth embodiment, wherein the light-sensitive elements <NUM> are mounted on a curved, dome-like substrate <NUM> and the top surface <NUM> is shaped correspondingly. Thus, the sensitivity to light rays coming from aside is increased, in particular if the top surface <NUM> extends above a level of the vehicle roof. In general, so for all embodiments, it is noted that positioning the sensor unit <NUM> at a highest location of the vehicle roof may be expected to provide the largest field of detection.

The first to fourth embodiments of the sensor unit <NUM> are based on similar concept of detection. The roof mountable sensor system may employ, however, any other detection concept. For example, <FIG> illustrates a transparent panel <NUM> comprising a first transparent sheet <NUM>, a variable transmissivity sheet <NUM> and a light-blocking layer <NUM>, wherein the light-blocking layer <NUM> may be only locally present, e.g. in the second section as illustrated in <FIG>.

The variable transmissivity layer <NUM>, i.e. a dimmable layer, is a well-known kind of layer, that is operable by application of an electrical current to change its transmissivity. The dimmable layer <NUM> may be segmented into smaller area's that are independently operable, so that a transmissivity may be locally reduced, for example to block a direct view of the sun.

A small through hole <NUM> is provided in the light-blocking layer <NUM>. As a result, a relatively small part of light from the first bundle of rays B1 shines through along line B1' or from the second bundle of rays B2 along line B2'. Thus, the hole <NUM> may be projected on a light sensitive array <NUM>, e.g. a CCD or CMOS image sensor. Image processing techniques may then be applied to determine an intensity of the light and a position of the corresponding light source.

In the illustrated embodiment, the variable transmissivity layer <NUM> is arranged over the through hole <NUM>. Thus, the light intensity as determined at the light sensitive array <NUM> is reduced by the variable transmissivity layer <NUM> depending on the transmissivity state of the variable transmissivity layer <NUM>. In such embodiment, the sensor unit may be operatively coupled to a control unit (not shown) for controlling the variable transmissivity layer <NUM>, wherein the intensity of the light coming into the passenger compartment is accurately controllable using an output of the sensor unit as a feedback signal, representing an accurate measure for the amount of light actually passing through the transparent panel <NUM>. Further, if segmented, the variable transmissivity layer <NUM> may be controlled to have a locally higher or lower transmissivity depending on a detected position of a light source like the sun.

<FIG> illustrates a further embodiment of the roof mountable sensor system, wherein the sensor system comprises a number of sensor subunits. In the illustrated embodiment, the sensor system comprises four sensor subunits <NUM>, <NUM>, <NUM> and <NUM>, each arranged at one of four corners of the transparent panel <NUM>. The subunits <NUM>, <NUM>, <NUM> and <NUM> do not have an omnidirectional field of detection. Instead, the subunits <NUM>, <NUM>, <NUM> and <NUM> have a field of detection DF1, DF2, DF3, DF4, respectively, in the X-Y plane corresponding to only half of such an omnidirectional field of detection. Combining the output of each of the subunits <NUM>, <NUM>, <NUM> and <NUM> provides an omnidirectional detection result.

Moreover, due to a common curvature of the vehicle roof, the arrangement of the subunits <NUM>, <NUM>, <NUM> and <NUM> may be advantageous. The roof usually curves downward towards the sides of the vehicle. As a result, the subunits <NUM>, <NUM>, <NUM> and <NUM> may be tilted such to receive even light rays coming from aside, cf.

<FIG> illustrates further embodiment, wherein an autonomous driving function is provided by mounting of a second sensor system <NUM> on the roof, in this case on the front header panel <NUM>, of the vehicle <NUM>. For example, the second sensor system <NUM> may be a camera system or a LIDAR system and a transmissive panel <NUM> may be arranged at a front side of the second sensor system <NUM>. Such a second sensor system <NUM> may be sensitive to an excessive amount of light or a locally intense light source, like the sun, in its field of detection. The sensor system <NUM> for detecting such light sources as a first sensor system may be arranged in a same housing as the second sensor system <NUM>, for example. The output of the first sensor system <NUM> may then be used to interpret, correct, compensate or ignore an output of the second sensor unit <NUM>.

<FIG> illustrates yet another embodiment, wherein the transparent panel <NUM> is moveably mounted on the roof of the vehicle <NUM>. In this embodiment, the sensor system <NUM> is mounted on the moveably arranged panel <NUM>. When the panel <NUM> is moved to an open position, for example to a tilted position as illustrated, an angle relative to the vehicle is changed. Similarly, an angle of incidence of incident light is changed. In order to compensate for such change, a control unit operatively coupled to or part of the sensor system may correct for the changed orientation and/or position. Such a correction may be based on a predetermined position and orientation or may be based on an output of a specific sensor, e.g. a gyroscopic sensor, mounted with the sensor system <NUM> on the moveably arranged panel <NUM>. As apparent to those skilled in the art, other movements or changes in orientation may be compensated as well.

Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in expectedly any appropriately detailed structure.

Further, the terms and phrases used herein are not intended to be limiting, but rather to provide an understandable description of the invention. The terms "a" or "an", as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language). The term coupled, as used herein, is defined as connected, although not necessarily directly.

Claim 1:
A roof assembly for a vehicle (<NUM>), the roof assembly comprising a roof mountable sensor system (<NUM>) for mounting on a roof (<NUM>) of the vehicle (<NUM>), the sensor system comprising a sensor unit (<NUM>), wherein the sensor unit comprises an omnidirectional incident-light detector that detects an incident-light intensity and a light-source position relative to the vehicle, characterized in that the roof assembly further comprises a moveably arranged panel (<NUM>) comprising a transparent pane, wherein the sensor unit (<NUM>) is mounted at the interior surface of the moveably arranged transparent panel (<NUM>) and wherein an output of the sensor unit (<NUM>) is compensated for change in orientation of the sensor unit, when moved with the moveably arranged transparent panel (<NUM>), by a control unit operatively coupled to, or part of, the sensor system (<NUM>).