Lens for an optical sensor system and method for producing same

Abstract

The invention relates to a lens (10) for an optical sensor system (20), which is intended for arrangement in an optical path of the sensor system (20), wherein the lens (10) has a chamfer (12) in at least one edge region, wherein the optical properties of the optical path depend on the chamfer (12). The invention also relates to an array of lenses (10), an optical sensor system (20) and a method for producing a lens (10) for an optical sensor system (20).

Description

[0001] LENS FOR AN OPTICAL SENSOR SYSTEM AND METHOD FOR MANUFACTURING THE SAME

[0002] Technical area

[0003] The application relates to a lens and an array of lenses for optical sensor systems, in particular lidar systems, as well as a method for producing such a lens.

[0004] background

[0005] Modern vehicles (cars, vans, trucks, motorcycles, etc.) are equipped with a multitude of sensor systems whose data is used to inform the driver and / or provide data to driver assistance systems. These sensor systems record the vehicle's surroundings, including other road users. Based on the recorded data, a model of the vehicle's environment can be created, and changes in this environment can be responded to.

[0006] Sensor systems are constantly being developed for various functions, e.g., for the acquisition of environmental information in the near and far range of vehicles, such as passenger cars or commercial vehicles. Sensor systems can also be used for driver assistance systems, especially assistance systems for autonomous or semi-autonomous vehicle control. They can be used, in particular, to detect obstacles and / or other road users in the front, rear, or blind spot area of ​​a vehicle. Sensor systems can be based on various sensor principles, such as radar, ultrasound, and optics.

[0007] An important optical sensor principle for environmental detection, e.g. of vehicles, is LIDAR technology (Light Detection and Ranging). A LIDAR system has an optical transmitter and an optical receiver. The transmitter can emit an optical signal in the form of light, which can be continuous or pulsed. Furthermore, the optical transmission signal can be modulated. In a LIDAR system, light in the form of laser beams in the ultraviolet, visible, or infrared range can be used. The receiver can receive the light after it has been reflected from an object in the vicinity of the LIDAR system. The received optical signal can be evaluated using the transmitted optical signal, e.g., using a time-of-flight method, and the spatial position and distance of the object from which the reflection occurred can be determined.In this context, reflection or reflected light is understood to mean any light that is thrown back and is intended to include, in particular, light that is thrown back by scattering or absorption-emission.

[0008] EP2943820B1 describes a method for manufacturing an array of optical lenses. The array is produced from a preform by milling a groove between the lenses into the preform to reduce crosstalk between the lenses.

[0009] Overview

[0010] A lens for an optical sensor system is provided for arrangement in an optical path of the sensor system. The lens, which is designed as an optical lens, has a chamfer in at least one edge region. The optical properties of the optical path depend on the chamfer of the lens. The chamfer is, in particular, arranged in the edge region or edge regions of the lens in such a way that the properties of the light propagating along the optical path are influenced by the chamfer of the lens. In particular, the chamfer is designed to improve the optical quality of the light propagating along the optical path.

[0011] The optical sensor system may, for example, comprise a lidar system with an optical transmitter, an optical receiver, and a computing device. The optical sensor system may be intended for use in a vehicle.

[0012] An optical lens is an optical element made of an optically transparent material, such as glass or optical plastic. An optical lens can have a curved shape. The lens converges and / or disperses light rays through refraction and / or reflection. It can be used to focus, diverge, and / or correct light. The shape of the lens can be convex or concave, or both, e.g., one on either side. The ability of the lens to affect light rays can also depend on its curvature and refractive index.

[0013] The bevel is designed to influence the lens's ability to focus and / or scatter light. In particular, the bevel can be designed to improve the lens's ability to focus and / or scatter light. The bevel can also be designed, for example, to reduce optical artifacts of the lens. Optical artifacts include unwanted effects or disturbances that can occur in optical systems and affect the quality or accuracy of images from the optical system and / or measurements performed by the optical system. The bevel also influences, in particular, optical artifacts that are at least partly caused by the lens. An optical artifact can, for example, be optical crosstalk, also known as blooming.

[0014] In one embodiment, the lens is intended for placement in a reception path of the sensor system. The reception path of the light in an optical sensor system is the optical path along which the light is received. An optical reception device of the sensor system comprises at least part of the reception path. The lens can be configured to change the optical properties of the light L.

[0015] In one embodiment, the lens is designed to guide light to a receiving sensor of the sensor system. The lens is arranged in the receiving path upstream of the receiving sensor of the receiving device. The light thus passes through the lens before reaching the receiving sensor. The lens can be configured to modify the optical properties of the light L such that it is guided, in particular focused, to the receiving sensor. This can improve the light yield when receiving the light.

[0016] The receiving device includes the receiving sensor for receiving the light. The receiving sensor converts the received light into an electrical received signal. For this purpose, the receiving sensor can include, for example, photosensitive elements, such as photosensitive semiconductor elements such as photodiodes. Image data from the optical sensor system can then be determined from the received signal.

[0017] In one embodiment, the receiving sensor has an array of pixels. In this embodiment, the lens is configured to direct the light onto the array of pixels. For example, the lens can direct individual partial beams of light onto individual pixels of the array. The beam direction can depend on the spatial direction from which the light hits the lens.

[0018] The field of pixels, also called a pixel array or pixel matrix, has at least two pixels for receiving the light. The pixel matrix can also have more than two pixels. Using the pixels, the receiving sensor converts the received light into the electrical received signal. For this purpose, the respective pixel can, for example, have at least one photosensitive element. Each pixel can, for example, receive the light from a particular spatial direction and convert it into a respective electrical received signal. The image data can then be determined from the received signals of the respective pixels.

[0019] In one embodiment, the lens is intended for arrangement in a lens array. The arrangement and / or design of the bevel reduces optical crosstalk with other lenses in the array. The lens array comprises an array of multiple lenses, which may be identical or different. The lens array can, for example, provide for the arrangement of the lenses as a matrix.

[0020] The lens can be designed to guide light to one or more pixels. It can be provided that a respective lens of the array guides light to a respective pixel of the pixel array of the receiving sensor. The light guidance can depend on the spatial direction from which the light is received. The bevel is attached to at least one of the lenses of the lens array in such a way that less light from this lens optically crosses over to other, particularly neighboring, lenses of the array.

[0021] The lens can be configured to guide light to a plurality of pixels. A respective optical channel can be provided for guiding light to each pixel of the plurality of pixels, with the respective optical channel depending on the direction of incidence of the light. An optical channel can, for example, correspond to a partial beam of light. Different optical channels can be guided by the lens in different directions.

[0022] For example, a respective lens can direct light to multiple pixels in the pixel array of the receiving sensor. For example, the lens can direct individual partial beams of light to pixels in the pixel array via individual optical channels. The beam direction can depend on the spatial direction from which the light hits the lens.

[0023] For example, it can be provided that a respective lens of the array directs light to several respective pixels of the pixel array of the receiving sensor. For example, a respective lens of the array can direct respective partial beams of light to pixels of the array. The beam direction can depend on the spatial direction from which the light hits the lens.

[0024] Mixed forms are also possible within a lens array. The lens array can include lenses that direct light to one pixel, and the array can include lenses that direct light to multiple pixels.

[0025] In one embodiment of the lens, the arrangement and / or design of the chamfer reduces optical crosstalk between the pixels of the receiving sensor. Optical crosstalk between the pixels of the receiving sensor is an undesirable effect that affects the quality of images from the optical sensor system and / or the accuracy of measurements made by the optical sensor system. With optical crosstalk, also called blooming, received light in the receiving sensor and thus in the image data can bleed into neighboring pixels. The chamfer is applied to the lens or lenses of the lens array in such a way that optical crosstalk between pixels of the receiving sensor is reduced. By applying the chamfer to the lens or lenses, the optical quality of the receive path can be improved.

[0026] In embodiments, the lens or lenses of the lens array can be made of glass and / or an optical plastic. Glass has a high temperature resistance, while plastic offers weight advantages. The lens or lenses can be formed in one piece. This can ensure easy manufacture and handling. The chamfer can be arranged in at least one peripheral region of the lens. The chamfer of the lens has a beveled edge and / or a rounded surface located in at least one edge region of the lens. If the lens has a largely round shape, the chamfer can, for example, extend along the circumference of the lens and, for example, have the shape of a bevel.

[0027] In embodiments of the lens, the bevel is arranged in at least one edge region facing the light on the optical path. This arrangement of the bevel has been shown to have a positive effect on the optical efficiency of the lens.

[0028] The field of lenses contains one or more of the lenses described.

[0029] The optical sensor system for environmental detection includes the optical receiving device with the receiving sensor and one or more of the described lenses in the optical path, in particular in the optical receiving path. The optical sensor system can, in particular, comprise a lidar system.

[0030] In a method for manufacturing an optical lens for an optical sensor system, the lens is intended for placement in an optical path of the sensor system. In the method, a chamfer is applied to at least one edge region of the lens in such a way that it influences the optical properties of the optical path. The chamfer can be applied to the lens, for example, by milling.

[0031] In particular, the chamfer can be applied in such a way that optical crosstalk between lenses of a lens array is reduced. Alternatively or additionally, the chamfer can be applied in such a way that optical crosstalk between optical channels of the lens is reduced. For example, if the lens has multiple optical channels, it can guide partial beams of light in different directions—e.g., depending on the direction of incidence—the chamfer can be applied in such a way that optical crosstalk between these optical channels of the lens is reduced. List of chamfers

[0032] In the following, embodiments of this application are further explained and described with reference to the figures.

[0033] Fig. 1 schematically shows a lens without and with bevel,

[0034] Fig. 2 Magnifications of a peripheral area of ​​the lens,

[0035] Fig. 3 schematically shows an array of lenses and an array of pixels,

[0036] Fig. 4 shows a schematic of a vehicle with an optical sensor system.

[0037] The same reference numerals are used throughout the figures to refer to identical or similar elements. Representations in the figures may not be to scale.

[0038] Flower description

[0039] Figure 1 schematically shows a lens 8 without a bevel and a lens 10 with a bevel 12. The bevel 12 can be applied to the lens 8, for example, by milling in the edge regions. Milling then creates the bevel 12, which is formed as flat planes in the edge regions of the lens 10. The bevel 12 is designed to change the optical properties of the lens. In particular, the optical dispersion of the lens 10 is reduced. The bevel 12 can optionally also be applied to only one or more edge regions of the lens 10. This allows the optical properties of the lens 10 to be further fine-tuned.

[0040] In particular, the bevel 12 can be attached to the lens 8 in such a way that the direction from which the light is to be influenced by the lens 10 is taken into account. For example, the bevel can then be arranged on the side of the lens 10 from which the light is incident.

[0041] If the lens 10 has a round shape, which can, for example, be substantially rotationally symmetrical to an optical axis of the lens 10, the chamfer 12 can, for example, extend along the circumference of the lens 10. Optionally, only parts of the circumference can be provided with the chamfer 12. In this case, it can then be provided to change the optical properties of the lens 10 only in certain directions. For example, the optical properties of the lens 10 can be changed with respect to planes in space that extend along the optical axis of the lens 10 and are intersected by the chamfer 12.

[0042] Figure 2 shows enlarged views of an edge region of lens 8 and lens 10. Figures 2 a) and b) show exemplary edge regions of lens 8. The edge regions exhibit elevations. In Figure 2 c), a flat surface has been created in the edge region, e.g., by milling. The milled area can be approximately in the range of a few hundred pm.

[0043] Figure 3 schematically shows an array 16 of lenses 10 and an array 14 of pixels Px. The array 16 of lenses 10 is located, for example, in an optical reception path of a reception device 24 of an optical sensor system 20. Light L is incident on the optical reception path. The light L is guided via the array 16 of lenses 10 onto the array 14 of pixels Px of an optical reception sensor. By means of the pixels Px of the optical reception sensor, the incident light is converted into an electrical sensor signal, which can be further processed. The reception signal of the optical sensor system 20 can be determined from the electrical sensor signal and can then be further processed, for example, in a computing device 28 of the optical sensor system 20.

[0044] The optical sensor system 20 can be designed, for example, as a lidar system with a transmitting device 22 and a receiving device 24. In other embodiments, the optical sensor system 20 can also be designed, for example, as a camera system without an optical transmitting device 22.

[0045] By using the described lenses 10 in the field 16, the light can be directed to the field 14 of pixels Px with good optical quality and minimal optical artifacts. In the example shown, for example, a respective lens 10 can direct a respective partial beam of light L to a respective pixel Px. The direction of the guidance through the respective lens 10 can depend on the direction from which the light L is incident. Each of the lenses 10 of the field 16 can therefore be adapted to guide light L, which is incident from a specific solid angle, to a specific pixel Px. The chamfer 12 attached to the lenses 10 allows the light L to be guided with great precision and minimal optical artifacts.

[0046] Figure 4 schematically shows a vehicle 30, for example a passenger car, with the optical sensor system 20, which may have a lidar system. The optical sensor system 20 is arranged in the front area of ​​the vehicle 30. The surroundings 32 detected by the optical sensor system 20 are located in front of the vehicle 30 in the direction of travel. An object O is schematically shown in the surroundings 32. The lidar system 20 has the transmitting device 22 for emitting the light L. The transmitting device 22 can, in particular, have a light source for emitting laser light. The optical sensor system 20 further has the receiving device 24 for receiving the reflected light L. The receiving device 24 has the receiving sensor with the array of pixels Px for receiving the light L, by means of which light L can be converted into the electrical sensor signal. The transmitted and received light L can be evaluated in a computing device 28, e.g.to detect the object O and / or to determine the distance to the object O. The computing device 28 can also monitor and control the transmission process in the transmission device 22 and the reception process in the reception device 24.

[0047] In the example shown, the surroundings 32 in front of the vehicle 30 can be monitored in the direction of travel. It is also possible to arrange the optical sensor system 20 in other areas of the vehicle 30, for example, in the rear area and / or in the side areas. It is also possible to arrange multiple optical sensor systems 20 on the vehicle 30, in particular in corner areas of the vehicle 30.

[0048] With the lidar system 20, stationary or moving objects O, in particular vehicles, persons, animals, plants, obstacles, road surface irregularities, in particular potholes or stones, road markings, traffic signs, open spaces, in particular parking spaces, precipitation or the like, can be detected in the environment 32.

Claims

CLAIMS 1. Lens (10) for an optical sensor system (20), which is intended for arrangement in an optical path of the sensor system (20), wherein the lens (10) has a chamfer (12) in at least one edge region, wherein the optical properties of the optical path depend on the chamfer (12).

2. Lens according to claim 1, wherein the lens (10) is provided for arrangement in a receiving path of the sensor system (20).

3. Lens according to claim 2, wherein the lens (10) is designed to direct light (L) to a receiving sensor of the sensor system (20).

4. Lens according to claim 3, wherein the lens (10) is configured to direct light (L) to a receiving sensor having an array of pixels (14).

5. Lens according to claim 1, wherein the lens (10) is provided for arrangement in an array of lenses (16), wherein the arrangement and / or formation of the bevel (12) reduces optical crosstalk to further lenses (10) of the array (16).

6. Lens according to claim 5, wherein the lens (10) is provided for guiding light to one or more pixels (Px).

7. Lens according to one of claims 4 to 6, wherein the lens (L) is designed to guide light for a plurality of pixels (Px), wherein a respective optical channel is provided for the light guide for a respective pixel (Px) of the plurality of pixels (Px), wherein the respective optical channel depends on the direction of incidence of the light (L).

8. Lens according to one of claims 4 to 7, wherein the arrangement and / or formation of the bevel (12) reduces optical crosstalk between the pixels (Px).

9. Lens according to one of the preceding claims, wherein the lens (10) is made of glass and / or an optical plastic.

10. Lens according to one of the preceding claims, wherein the lens (10) is formed in one piece.

11. Lens according to one of the preceding claims, wherein the bevel (12) is arranged in at least one peripheral region of the lens.

12. Lens according to one of the preceding claims, wherein the bevel (12) is arranged in at least one edge region which faces the light (L) on the optical path.

13. Array of lenses (14) comprising at least one lens (10) according to one of the preceding claims.

14. Optical sensor system (20) for environmental detection, comprising an optical receiving device (24) with a receiving sensor and a lens (10) according to one of claims 1 to 12 in an optical path.

15. A method for producing a lens (10) for an optical sensor system (20), wherein the lens (10) is provided for arrangement in an optical path of the sensor system (20), wherein in at least one edge region of the lens (10) a chamfer (12) is applied such that it influences the optical properties of the optical path.

16. The method according to claim 15, wherein the bevel (12) is applied so as to reduce optical crosstalk between lenses (10) of an array of lenses (16) and / or between optical channels of the lens (10).

17. The method according to claim 15 or 16, wherein the chamfer (12) is applied by milling.

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