WO2023057485A1

WO2023057485A1 - Sensor unit and vehicle

Info

Publication number: WO2023057485A1
Application number: PCT/EP2022/077642
Authority: WO
Inventors: Donald Peyrot
Original assignee: Valeo Schalter Und Sensoren Gmbh
Priority date: 2021-10-08
Filing date: 2022-10-05
Publication date: 2023-04-13
Also published as: DE102021126105A1

Abstract

There is provided a sensor unit (2) for a vehicle (1), comprising: an optical sensor (7); and an optical element (13) arranged in front of the optical sensor (7), the optical element (13) comprising a convex surface (20, 20') facing away from the optical sensor (7) and a concave surface (21) facing towards the optical sensor (7), wherein the convex surface (20, 20') has a longer radius (R, R') of curvature than the concave surface (21); wherein the convex surface (20, 20') has a shape which is non-rotationally symmetric about an axis (A) intersecting the optical element (13) and the optical sensor (7).

Description

SENSOR UNIT AND VEHICLE

The present invention relates to a sensor unit for a vehicle and to a vehicle comprising such a sensor unit.

Optical sensors are widely used in the automotive industry for monitoring the external environment of the vehicle. Such optical sensors typically include cameras or lidars.

It is desirable to have optical sensors with a wide horizontal field-of-view (FOV), ideally up to 180° or more. In order to achieve a high field-of-view, it is known to use optical sensors together with a fisheye lens. Such designs allow a field-of-view of, for example, larger than 200°. It has been found that such designs also have a wide vertical field-of-view. This results in the optical sensor collecting invaluable information since, under normal circumstances, there is no obvious reason to monitor the sky or the road directly under the vehicle.

US 2018/0249126 A1 discloses a vehicle indicia assembly including a vehicle indicia element configured to be mounted to a vehicle. The vehicle indicia element comprises a light transmitting portion. A vehicle camera comprising a fisheye lens is positioned at the vehicle indicia element so that the vehicle camera views through the light-transmitting portion and is operable to capture image data.

US 2018/0335622 A1 discloses a device for an optical sensor for a motor vehicle. The device includes a housing accommodating the optical sensor. The housing further includes an optical element fastened thereto. The optical element has at least one planar surface that is configured to be placed in the field-of-view of the optical sensor. The optical sensor may comprise a fisheye.

It is one object of the present invention to provide an improved sensor unit. According to a first aspect, a sensor unit comprising an optical sensor and an optical element is provided. The optical element is arranged in front of the optical sensor, the optical sensor comprising a convex surface facing away from the optical sensor and a concave surface facing towards the optical sensor, wherein the convex surface has a longer radius of curvature than the concave surface. The convex surface has a shape which is non-rotationally symmetric about an axis intersecting the optical element and the optical sensor.

By having the convex surface with a shape which is non-rotationally symmetric about an axis intersecting the optical element and the optical sensor, an image can be projected onto the optical sensor corresponding to a variable field-of-view. For example, the vertical field-of- view may, thereby, have a different angle (or width) than the horizontal field-of-view. More generally speaking, using a convex surface having the above-defined shape, the field-of-view can be adjusted or provided in accordance with information needs in any direction. For example, said axis may intersect a light-sensitive element (in particular chip) of the optical sensor at right angles.

The sensor unit may be particularly suitable to be used in a vehicle. Examples of the vehicle may include motor vehicles, such as a motorcycle, car, truck or bus; railed vehicles, such as a train or tram; watercraft, such as ships or boats; an amphibious vehicle, such as a screw- propelled vehicle or a hovercraft; an aircraft, such as an airplane or a helicopter; or spacecraft. Examples of the vehicle also may include a robot, such as an industrial robot, an autonomously moving robot, and the like.

An "optical sensor" is a sensor configured to output an electrical signal depending on light (visible or invisible) received by the sensor.

According to an embodiment, the convex surface comprises a portion of a cylinder surface.

In particular, the cylinder surface has an axis of rotational symmetry. For example, the cylinder surface may comprise one or more axes of rotational symmetry. In particular, the cylinder surface may comprise exactly one axes of rotational symmetry. Advantageously, a cylinder surface having, for example, exactly one axis of rotational symmetry is configured to provide a large horizontal field-of-view and a small vertical field-of-view. At the same time, this kind of cylinder surface is easy to manufacture.

A "cylinder surface" herein refers to a surface generated by moving a curve in a first plane along a straight line to a second plane, the straight line being arranged outside said first plane. The lines connecting the curve in the first and second plane form the cylinder surface.

According to another embodiment, the convex surface may comprise a portion of an ellipsoid surface. For example, the optical element is shaped as a portion of an ellipsoid comprising on its outside the portion of the ellipsoid surface. In other words the convex surface may be aspherical. In an additional embodiment, also the concave surface may comprise a portion of an ellipsoid surface (or in other words may also be aspherical).

According to a further embodiment, the optical element is shaped as a cylindrical portion comprising on its outside the portion of the cylinder surface.

This is to say that the optical element as a whole is shaped as a portion of a cylinder. In particular, said cylinder portion corresponds to a portion of a hollow cylinder. In this manner, an optical element with the above-defined concave and convex surfaces is easily obtained.

According to a further embodiment, the cylindrical portion corresponds to a cut-off cut in the lengthwise direction from a hollow cylinder, wherein the cut intersects the cylinder sidewall twice. "Lengthwise direction" refers to the axial direction of the hollow cylinder. This is in some embodiments the axis around which the hollow cylinder is rotationally symmetric. An optical element with this shape can be easily manufactured, for example by casting, injection-molding or extrusion.

According to a further embodiment, the optical element is a protective cover.

Thus, the optical element has a dual function: In addition to its optical characteristics, the optical element protects the optical sensor. For example, it prevents external mechanical forces from acting on the optical sensor, and/or it may prevent dust, dirt and other undesirable materials from reaching the optical sensor.

According to a further embodiment, the optical element is configured to be mounted to the outside of a vehicle body.

For example, the optical element may comprise engaging and/or receiving elements, such as hooks, clips, receptables and the like, in order to be fastened to the outside of the vehicle body.

According to a further embodiment, the optical element is made of a transparent material.

For example, the optical element may be made of glass or plastics. "Transparent" is to say that the optical element allows light to pass through from the external environment, in particular around a vehicle, to the optical sensor.

According to a further embodiment, the optical element is a lens.

According to a further embodiment, the optical sensor comprises a lens, an image plane of the sensor unit being arranged behind the lens. Advantageously, in this embodiment, the optical element can be designed to shape the light impinging on the (outside) convex surface, and then passing therethrough and leaving the optical element through the (inside) concave surface in any suitable way. That is, there may be no image plane arranged directly behind the optical element. Rather, the optical sensor itself comprises a lens transforming the light coming from the optical element, such as to regain the original image.

According to a further embodiment, the optical sensor comprises a housing and/or chip, the lens being connected to or integrally formed with the housing and/or chip.

The optical sensor thus forms, together with the lens, a unit. This unit may be separate and/or spaced apart from the optical element. In particular, the chip comprises a light-sensitive element, generating an electrical signal depending on light impinging on the chip.

According to a further embodiment, the optical sensor is a camera or lidar.

In particular, the optical sensor comprises, for example, a CCD (charge coupled device) or CMOS (complementary metal oxide semiconductor) chip (in the case of a camera). "Lidar" refers to a method where distances are determined based on a laser signal sent out and a reflected signal received by the optical sensor.

According to a further embodiment, the sensor unit has a field-of-view larger than 120°, preferably larger than 150°, and even more preferably larger than 180°.

The sensor unit is configured to, when mounted on a vehicle, provide said field-of-view in the horizontal direction. The field-of-view in the vertical direction will thus be smaller than the field-of-view in the vertical direction.

According to a second aspect, a vehicle comprising the sensor unit as described above is provided. According to an embodiment, the axis about which the shape is non-rotationally symmetrical is orientated horizontally.

The horizontal direction corresponds to the typical viewing direction of cameras or lidars in the automotive field. "Horizontal" presently also includes deviations from exactly horizontal of up to 10, 20 or 30 degrees, for example.

According to a further embodiment, the axis of symmetry is oriented vertically.

Thereby, a large field-of-view may be obtained in the horizontal direction. "Vertical" presently also includes deviations from exactly vertical of up to 10, 20 or 30 degrees, for example.

According to a further embodiment, the vehicle further comprises a vehicle body, wherein the optical element is arranged outside the vehicle body, and the optical sensor is arranged inside the vehicle body.

This is advantageous in that the optical element outside the vehicle body ensures a large field-of-view and, at the same time, the optical sensor is safely arranged inside the vehicle body.

According to a further embodiment, the sensor unit has a horizontal field-of-view and a vertical field-of-view, wherein the horizontal field-of-view is larger than the vertical field-of-view.

This avoids unnecessary data from being collected by the sensor unit.

Features explained above with regard to the first aspect, equally apply to the second aspect, and vice versa. Further possible implementations or alternative solutions of the invention also encompass combinations - that are not explicitly mentioned herein - or features described above or below with regard to the embodiments. The person skilled in the art may also add individual or isolated aspects and features to the most basic form of the invention.

Further embodiments, features and advantages of the present invention will become apparent from the subsequent description and dependent claims, taken in conjunction with the accompanying drawings, in which:

Fig. 1 shows an example of a vehicle in a front view;

Fig. 2 shows a section ll-ll taken from Fig. 1 ;

Fig. 3 shows raytracing through an optical element shown in Fig. 2 in a top view;

Fig. 4 shows raytracing for the optical element of Fig. 3 in a side view;

Fig. 5 shows the section view of Fig. 2 in accordance with a further embodiment;

Fig. 6 shows the section view of Fig. 2 in accordance with an even further embodiment; and

Fig. 7 shows the embodiment of Fig. 6 in a side view.

In the figures, like reference numerals designate like or functionally equivalent elements, unless indicated otherwise.

Fig. 1 shows an embodiment of a vehicle 1 according to an embodiment. According to the embodiment, the vehicle 1 is a passenger car. The vehicle 1 comprises a sensor unit 2 by way of example only, the sensor 2 is shown to be integrated into the nose of the vehicle 1 . However, the sensor unit 2 or multiple sensor units 2 could be integrated into different parts of the vehicle, for example in the vehicle sides or in the vehicle rear, in the vehicle mirrors or in or at any other suitable position.

Fig. 2 shows a section ll-ll taken from Fig. 1 . The section view of Fig. 2 shows a portion of the vehicle body 3. The vehicle body 3 could be made up of metal sheet, plastics or the like. The vehicle body 3 comprises an opening 4 connecting the inside 5 of the vehicle body 3 with the outside or exterior environment 6.

The sensor unit 2, according to the embodiment, comprises an optical sensor 7 which, according to the embodiment of Fig. 2, is a camera. For example, the optical sensor 7 is arranged at least partially inside the opening 4, which is, for example, a through-hole formed inside the vehicle body 3.

The optical sensor 7 may comprise a lens 8, a housing 9 and a light-sensitive element 10. According to the embodiment of Fig. 2, in which the optical sensor 7 is formed as a camera, the light-sensitive element 10 is configured as a CCD or CMOS chip, for example. The lightsensitive element 10 is arranged, for example, inside the housing 9 which is why it is shown in dotted lines. The lens 8 is configured to project light 11 coming from the outside or exterior 6 onto the light-sensitive element 10. In particular, there is an image plane 12 formed behind the lens 8. "Behind" and "in front" herein refers to the light 1 1 passing through respective optical elements.

The lens 8 may be connected or formed integrally with the housing 9 and/or with the lightsensitive element 10. Generally speaking, the light-sensitive element 10 is configured to generate an electrical signal depending on the incoming light 11 .

An optical element 13 is arranged on the exterior side 14 of the vehicle body 3. The optical element 13 may be connected directly to the vehicle body 3, for example by means of clips (not shown), or to an intermediate component connected to the vehicle body 3. In one embodiment (also not shown), the optical element 13 may also be connected to the optical sensor 7, for example to the housing 9 of the optical sensor 7.

The optical element 13 is, for example, made of a transparent material, which is, for example, a transparent plastic material or glass. The optical element 13 may be formed as a lens.

The optical element 13 covers the optical sensor 7. In particular, the optical element 13 covers the lens 8. In one embodiment, the optical element 13 covers completely the opening 4, thus preventing dust and other pollutants from ingressing and potentially damaging or mitigating the functionality of the optical sensor 7. The optical element 13 may also be referred to, according to an embodiment, as a protective cover. As such, it prevents mechanical forces from the outside or exterior 6 to act on the optical sensor 7.

The optical element 13 has, in the horizontal direction H, a fisheye shape which will be explained in more detail referring to Figs. 3 and 4 hereinafter.

Fig. 3 shows raytracing for light rays 15, 16, 17 for light rays 15, 16, 17 (forming part of the incoming light 11 ). Therein, Fig. 3 shows the optical element 13 of Fig. 2 in a top view. Fig. 4 shows more raytracing for the optical element 13, said element being shown in a slightly perspective side view. Therein, additional rays 18 and 19 are illustrated. In Figs. 3 and 4, the rays which have passed through the optical element 13 are indicated by

The optical element 13 has a convex surface 20 (see Fig. 3) facing away from the optical element 7 (see Fig. 2). The optical element 13 also comprises a concave surface 21 (see Fig. 3) facing towards the optical element 7 (see Fig. 2). The convex surface 20 has a radius R (of which only the tip is shown). Similarly, the concave surface 21 also has a radius r (of which again only a tip is shown). The radius R is longer than the radius r. The radii R, r both lie in the horizontal plane PH. The horizontal plane corresponds to the plane defined by the vehicle's longways and sideways direction. At least the convex surface 20 has a shape which is non-rotationally symmetric about an axis A (see Fig. 2 and 3). The axis A intersects the optical element 20 and the optical sensor 7. In particular, the axis A may intersect the light-sensitive element or chip 10, for example at right angles. According to the embodiment, the convex surface 20 comprises a portion 22 (see Fig. 4) of a cylinder surface having, foe example, a single axis of rotational symmetry 23 (see Fig. 4). The portion 22 is formed by shifting a first line 24 parallel by a (straight) distance 25, thus obtaining a second line 26. All straight lines 25 connecting the lines 24, 26 form the portion 22.

According to the example of Figs. 3 and 4, the concave surface 21 is also a portion of a cylinder surface having an axis of rotational symmetry (not shown). Thus, the optical element 13, altogether, is shaped as a cylindrical portion comprising on its outside the convex surface 20 and on its inside the concave surface 21 . For example, the cylindrical portion 27 is geometrically speaking obtained by a cut-off cut in a lengthwise direction L from a hollow cylinder 28 (the hollow cylinder 28 is shown in dotted lines), wherein the cut intersects the cylinder sidewall twice. The points of intersection are designated by reference numerals 29 and 30. The lengthwise direction L corresponds to the vertical direction V in which the distance 25 (vector) is orientated.

According to a further embodiment, which is not shown in detail in Fig. 4, the optical element 13 has a convex surface 20' being formed not straight in the vertical direction V, but having a radius of curvature R' in the vertical plane Pv larger than that of the curvatures R. The convex surface 20' may correspond to an ellipsoidal surface. The optical element 13 may be formed as a portion of an ellipsoid.

Both embodiments (concave surface 20, 20') provide for the presently desired effect. This effect is illustrated by the raytracings of Figs. 3 and 4. In the horizontal plane PH (Fig. 3), the optical element 13 provides for a large field-of-view of, for example, 180° as indicated by the angle a. On the other hand, in the vertical plane Pv (Fig. 4), the field-of-view is limited to an angle of, for example, 60°, as indicated by the angle in Fig. 4.

Fig. 5 illustrates the embodiment of Fig. 2. However, in this embodiment, the optical sensor 7 is arranged fully inside the vehicle body 3. As can be seen in both Figs. 2 and 5, the optical sensor 7 is spaced apart from the optical element 13, the distance in Fig. 5 being larger than in Fig. 2.

Fig. 6 illustrates an embodiment corresponding to the section of Fig. 2. However, the optical sensor 7 is formed as a lidar. As such, the optical sensor 7 comprises, for example, a transmitter 31 and a receiver 32 as illustrated in a side view taken from Fig. 6 and illustrated in Fig. 7. The transmitter 31 sends out a laser beam (not shown) which is reflected from the measured object (not shown). The reflected beam is received by the receiver 32. Based on the run time, the distance with respect to the measured object is determined.

Although the present invention has been described with reference to specific exemplary embodiments, it may be modified in numerous ways.

List of reference numerals

1 vehicle

2 sensor unit

3 vehicle body

4 opening

5 inside

6 outside

7 optical sensor

8 lens

9 housing

10 light-sensitive element

11 incoming light

12 image plane

13 optical element

14 exterior side

15-19, 15'-19' light rays

20, 20' convex surface

21 concave surface

22 portion

23 axis of symmetry

24 line

25 distance

26 line

27 portion

28 hollow cylinder

29 point of intersection

30 point of intersection

31 transmitter

32 receiver H horizontal direction

L lengthwise direction

PH horizontal plane P_v vertical plane

R, R' radius r radius

V vertical direction a angle/horizontal field-of-view

P angle/vertical field-of-view

Claims

1 . A sensor unit (2) for a vehicle (1 ), comprising: an optical sensor (7); and an optical element (13) arranged in front of the optical sensor (7), the optical element (13) comprising a convex surface (20, 20') facing away from the optical sensor (7) and a concave surface (21 ) facing towards the optical sensor (7), wherein the convex surface (20, 20') has a longer radius (R, R') of curvature than the concave surface (21 ); wherein the convex surface (20, 20') has a shape which is non-rotationally symmetric about an axis (A) intersecting the optical element (13) and the optical sensor (7).

2. The sensor unit of claim 1 , wherein the convex surface (20, 20') comprises a portion (22) of a cylinder surface, preferably having an axis of rotational symmetry (23).

3. The sensor unit of claim 2, wherein the optical element (13) is shaped as a cylindrical portion (27) comprising on its outside the portion (22) of the cylinder surface.

4. The sensor unit of claim 3, wherein the cylindrical portion (27) corresponds to a cut-off cut in the lengthwise direction (L) from a hollow cylinder (28), wherein the cut intersects (29, 30) the cylinder side wall twice.

5. The sensor unit of one of the preceding claims, wherein the convex surface (20, 20') comprises a portion of an ellipsoid surface.

6. The sensor unit of one of the preceding claims, wherein the optical element (13) is a protective cover and/or is configured to be mounted to the outside of a vehicle body (3).

7. The sensor unit of one of the preceding claims, wherein the optical element (13) is made of a transparent material and/or is a lens.

8. The sensor unit of one of the preceding claims, wherein the optical sensor (7) comprises a lens (8), an image plane (12) of the sensor unit (2) being arranged behind the lens

(8).

9. The sensor unit of claim 8, wherein the optical sensor (7) further comprises a housing

(9) and/or chip (10), the lens (8) being connected to or integrally formed with the housing (9) and/or chip (10).

10. The sensor unit of one of the preceding claims, wherein the optical sensor (7) is a camera or lidar.

11 . The sensor unit of one of the preceding claims, having a field-of-view (a) larger than 120 degrees, preferably larger than 150 degrees and even more preferably larger than 180 degrees.

12. The sensor unit of one of the preceding claims, wherein the sensor unit (2) has a horizontal field-of-view (a) and a vertical field-of-view (P), wherein the horizontal field-of-view (a) is larger than the vertical field-of-view (P).

13. A vehicle (1 ) comprising the sensor unit (2) of one of the preceding claims.

14. The vehicle of claim 13, wherein the axis (A) about which the shape is non-rotationally symmetrical is orientated horizontally.

15. The vehicle of claim 13 or 14, wherein the axis of rotational symmetry (23) is oriented vertically.

16. The vehicle of one of claims 13 to 15, further comprising a vehicle body (3), wherein the optical element (13) is arranged outside the vehicle body (3) and the optical sensor (7) is arranged inside the vehicle body (3).