Lidar sensor for detecting an object

Abstract

Lidar sensor for comprehensively detecting an object in the environment • at least one transmitting unit (102, 102a, 102b, 204, 204a, 204b) for emitting electromagnetic radiation (105, 105a, 105b), • at least one receiving unit (103, 103a, 103b, 204, 204a, 204b) for receiving electromagnetic radiation (106, 106a, 106b) reflected from the object, • at least one refractive element which is at least partially transparent to electromagnetic radiation (105, 105a, 105b, 106, 106a, 106b), • a rotating unit (101) comprising at least one refractive element, at least one transmitting unit (102, 102a, 102b, 204, 204a, 204b) and at least one receiving unit (103, 103a, 103b, 204, 204a, 204b), characterized in that • the at least one refractive element comprises at least one optical lens (107, 107a, 107b) and a beam splitter (201, 201a, 201b, 1201) for splitting the electromagnetic radiation (105, 105a, 105b, 106, 106a, 106b), wherein two focal planes (109, 109-1, 109-2, 109a-1, 109a-2, 109b-1, 109b-2) are present, and that • that at least one transmitting unit (102, 102a, 102b, 204, 204a, 204b) and at least one receiving unit (103, 103a, 103b, 204, 204a, 204b) are positioned in at least one focal plane (109, 109-1, 109-2, 109a-1, 109a-2, 109b-1, 109b-2) of at least one refractive element, and that • the lidar sensor comprises at least two receiver units (103a, 103b, 204a, 204b), wherein • a receiving unit (103a, 204a) is positioned in a first focal plane (109a-1, 109b-2) and wherein • the other receiving unit (103b, 204b) is positioned in a second focal plane (109b-1, 109a-2) aligned parallel to the first focal plane (109a-1, 109b-2), and wherein • the two receiving units are arranged offset from each other by a predetermined distance (402) along the orientation of the focal planes (109-1, 109-2, 109a-1, 109a-2, 109b-1, 109b-2).

Description

[0001] The present invention relates to a lidar sensor for detecting an object in the environment and a method for detecting an object with a lidar sensor according to the preamble of the independently formulated claims. State of the art

[0002] LiDAR (light detection and ranging) sensors are known from the prior art, enabling the detection of objects in the vicinity of the LiDAR sensor. In this system, a transmitter emits radiation into the environment, which is reflected or backscattered by objects and received by a receiver of the LiDAR sensor. Rotating LiDAR sensors, so-called macroscanners, are known in which the optical axes of the transmitter and receiver are parallel at a certain distance. In such macroscanners, a deflection unit, for example, in the form of a mirror or a mirror system, can be arranged in a rotating configuration. Macroscanners are also known in which the transmitter and receiver are located on a single rotating unit. These macroscanners have a relatively large footprint and, in particular, a relatively large height.

[0003] A lidar component is known from WO15026471. The component comprises a housing designed to rotate about an axis. The housing has an interior containing a transmitting unit, a receiving unit, and a common area. Within the common area, the transmitting unit has an exit aperture, and the receiving unit has an input aperture. The component further includes a plurality of light sources. These are configured to emit a plurality of light beams, which enter the common area through the exit aperture and travel through the common area via a transmission path. The light beams have wavelengths within a specific wavelength range. The component also includes a plurality of detectors in the receiving unit. These detectors are configured to detect light with wavelengths within a specific wavelength range.The component also includes an optical lens attached to the housing. The optical lens is designed to receive light rays via a transmission path and collimate them for transmission into the vicinity of the lidar component. The collimated light rays are reflected by one or more objects in the vicinity of the lidar component, and the reflected light is collected by the optical lens. The optical lens focuses the collected light onto the detectors via a receive path that extends through the common area and the receive aperture of the receiver unit.

[0004] Document DE 10 2011 076 493 A1 discloses a measuring device for measuring the distance between a reference mark and a target object, consisting of a beam source, a detector, a beam shaping system, an optical carrier and a printed circuit board, wherein during adjustment the components arranged in the optical carrier are adjustable in the direction of their optical axes and the component arranged on the printed circuit board is adjustable in a plane perpendicular to the optical axis.

[0005] Document DE 10 2014 107 353 A1 discloses an optoelectronic sensor for detecting objects in a monitoring area, which enables data transmission between a movable scanning unit and a base unit by means of a light guide arranged on a front window.

[0006] Document DE 20 2015 101 912 U1 discloses an optoelectronic sensor for detecting objects in a monitoring area with at least two different light emitters that generate emitted light spots with different beam geometries and / or polarization properties.

[0007] Document US 2004 / 0233460 A1 discloses a laser measuring device that directs multiple laser beams with different properties to an object via a common optical path and uses them to detect various object properties.

[0008] Document US 2014 / 0034817 A1 describes a device for object detection in which light beams from multiple light sources are bundled and used to scan an area by means of a deflection unit. Disclosure of the invention

[0009] The present invention relates to a lidar sensor for detecting an object in the environment. The lidar sensor comprises at least one transmitter for emitting electromagnetic radiation and at least one receiver for receiving electromagnetic radiation reflected by the object. The lidar sensor further comprises at least one refractive element, which is at least partially transparent to the electromagnetic radiation, and a rotating unit, which contains at least the at least one refractive element, the at least one transmitter, and the at least one receiver.

[0010] According to the invention, the at least one refractive element comprises at least one optical lens and a beam splitter for splitting the electromagnetic radiation, wherein two focal planes are provided. The at least one transmitting unit and the at least one receiving unit are positioned in at least one focal plane of at least one refractive element.

[0011] The at least one optical lens, as part of the refractive element, has only one focal plane. Because the beam splitter is also part of the refractive element, the refractive element has a total of two focal planes. For example, the lidar sensor can comprise a refractive element consisting of a beam splitter and one optical lens. The lidar sensor can also comprise a refractive element consisting of a beam splitter and two optical lenses. Furthermore, the lidar sensor can comprise two refractive elements. Each of the two refractive elements can consist of a beam splitter and one optical lens. Finally, each of the two refractive elements can consist of a beam splitter and two optical lenses.One of the two refractive elements can be formed from a beam splitter and an optical lens, and the other of the two refractive elements can be formed from a beam splitter and two optical lenses.

[0012] The advantage of the invention lies in the fact that the installation volume and / or height of the lidar sensor can be reduced compared to known solutions from the prior art. It is possible to reduce the diameter of the rotating unit. Furthermore, certain optical elements can be omitted. For example, separate optical lenses may not be necessary for the transmit and receive beam paths. It is also possible to use the same optical lens for both the transmit and receive beam paths. The rotation of the rotating unit enables measurements over an angular range of up to 360°. Measurements over an angular range smaller than 360° are also possible.

[0013] The optical lens, as part of the refractive element, can be transparent to electromagnetic radiation. Furthermore, the optical lens can refractively affect electromagnetic radiation. Refraction can occur when electromagnetic radiation passes through the optical lens. The beam splitter can be transparent to some parts of the electromagnetic radiation and reflective to others. The beam splitter can divide the radiation in a defined ratio. This ratio can depend on the design and / or materials of the beam splitter, as well as the physical properties of the electromagnetic radiation.

[0014] An object according to the invention can have an interface at which electromagnetic radiation can be reflected. The electromagnetic radiation can also be scattered at a scattering center of the object. An object according to the invention can be mobile or immobile. An object can, for example, be a living being or an inanimate obstacle in the environment. An object can, for example, be a road user, a vehicle, and / or a traffic control device. An object can also, for example, be an atom, a dust particle, or a water droplet in the environment.

[0015] The detection of an object within the meaning of the invention can be understood as the detection of the object's distance from the lidar sensor. The object's motion characteristics can also be detected. The object's position, orientation, velocity, acceleration, direction of movement, size, and physical properties can all be determined. Inferences can be drawn about the object's material, reflectivity, and whether it is wet or if water is present on its surface.It is possible to determine whether an object is iced over. It is possible to determine whether there is ice on the surface of an object.

[0016] In an advantageous embodiment of the invention, the beam splitter is designed to split the electromagnetic radiation in a polarization-selective and / or wavelength-selective manner. The advantage of this embodiment is that it allows conclusions to be drawn about the physical properties of the object from which the electromagnetic radiation was reflected. For example, the polarization conservation properties of the measured objects can be determined.

[0017] In a further advantageous embodiment of the invention, it is provided that further wavelength-selective and / or polarization-selective and / or polarization-modifying components are provided in a beam path of the transmitting unit and / or the receiving unit. One or more wavelength-selective filter elements may be present in the lidar sensor. One or more polarization-selective filter elements may be present in the lidar sensor. One or more bandpass filters may be present in the transmitting unit of the lidar sensor. One or more bandpass filters may be present in the receiving unit of the lidar sensor. One or more polarization filters may be present in the transmitting unit of the lidar sensor. One or more polarization filters may be present in the receiving unit of the lidar sensor.Such components can enable the lidar sensor to emit electromagnetic radiation of a predetermined wavelength into the environment. They can also enable the lidar sensor to emit electromagnetic radiation of a predetermined polarization into the environment. Furthermore, they can preferably ensure that electromagnetic radiation of a predetermined wavelength reaches the lidar sensor's receiver. This ensures that electromagnetic radiation reflected from the surrounding object reaches the lidar sensor's receiver. Interfering background radiation with a different wavelength and / or polarization does not reach the lidar sensor's receiver, or only reaches it in a significantly attenuated form.In this way, the signal-to-noise ratio can be improved. Polarization-changing components can be, for example, delay plates. These are also called λ / n plates. When electromagnetic radiation passes through such components, the polarization and phase of the radiation can be changed. For example, λ / 4 plates are known to convert linearly polarized electromagnetic radiation into circularly or elliptically polarized electromagnetic radiation. λ / 4 plates can also convert circularly polarized electromagnetic radiation into linearly polarized electromagnetic radiation. λ / 2 plates can rotate the polarization direction of linearly polarized electromagnetic radiation by a selectable angle.

[0018] In a further advantageous embodiment of the invention, the beam splitter is formed by a polarization-selective and / or wavelength-selective holographic element. The advantage of this embodiment is that the installation volume and / or height of the lidar sensor can be reduced even further. In holographic optical elements, the splitting of the electromagnetic radiation and the deflection of one portion of the electromagnetic radiation are achieved by diffraction at a volume grating. Volume gratings are films that are exposed, for example, by interference lithography. Through the exposure and / or the subsequent development process, the volume gratings can acquire various optical functionalities. One optical functionality can be polarization selectivity. Another optical functionality can be wavelength selectivity.The holographic optical elements can also be manufactured using cost-effective printing processes. The need for holographic multiplexing to manufacture the holographic optical elements can be avoided. The holographic optical elements can exhibit high diffraction efficiencies. The size of a lidar sensor can be reduced by using thin films. The size of a lidar sensor can be reduced by using malleable films. The height of a lidar sensor can be reduced by using thin films. The height of a lidar sensor can be reduced by using malleable films. The holographic optical elements can transmit electromagnetic radiation. The holographic optical elements can reflect electromagnetic radiation. They can be manufactured specifically for certain angles of incidence and reflection.They can be manufactured specifically for certain diffraction angles. This enables new lidar sensor designs. The holographic optical elements can also have other optical functionalities. In addition to their filtering functions, they can, for example, focus electromagnetic radiation onto a detector in the receiver unit. Or they can modify the beam shape of the electromagnetic radiation.

[0019] In a further advantageous embodiment of the invention, the at least one transmitting unit is designed to emit electromagnetic radiation of a selective wavelength range and / or a selective polarization direction. The advantage of this embodiment is that objects in the environment can be detected with greater accuracy. The wavelength of the emitted electromagnetic radiation can be selected such that, under known environmental conditions, such as a specific atmospheric attenuation, the most accurate measurement results possible are achieved. Different wavelengths can also offer specific advantages and / or disadvantages with regard to the reflectivities of different objects. By selectively choosing the wavelength of the emitted electromagnetic radiation, the most accurate measurement results possible can again be obtained.

[0020] In a further advantageous embodiment of the invention, the lidar sensor comprises at least two transmitting units. The wavelength range and / or polarization direction of the emitted electromagnetic radiation of the first transmitting unit differs from the wavelength range and / or polarization direction of the emitted electromagnetic radiation of the second transmitting unit. The advantage of this embodiment is that two different wavelengths can be measured simultaneously. A further advantage of this embodiment is that two different polarization directions can be measured. An object that has already been detected can be measured a second time by a second measurement with a different wavelength. The first measurement can thereby be verified.

[0021] In a further advantageous embodiment of the invention, the at least one receiving unit is designed to receive electromagnetic radiation of a specific wavelength range and / or a specific polarization direction. This can be achieved by including corresponding wavelength-selective components in the receiving unit. A wavelength-selective component can, for example, be a bandpass filter. Alternatively, at least one detector can be wavelength-selective as part of the receiving unit. The detector can have varying sensitivities to different wavelengths. The advantage of this embodiment is that objects in the environment can be detected with greater accuracy. A wavelength range can be selected that yields the most accurate measurement results under known environmental conditions, such as a specific atmospheric attenuation.Different wavelengths can offer specific advantages and / or disadvantages regarding the reflectivity of different objects. By selectively choosing the wavelength of the received electromagnetic radiation, it is possible to control which objects are detected. This, in turn, allows for the most accurate measurement results possible.

[0022] In a further advantageous embodiment of the invention, the lidar sensor comprises at least two receiving units. The wavelength range and / or polarization direction of the electromagnetic radiation received by the first receiving unit differs from the wavelength range and / or polarization direction of the electromagnetic radiation received by the second receiving unit. The advantage of this embodiment is that two different wavelengths can be measured simultaneously. A further advantage of this embodiment is that two different polarization directions can be measured simultaneously. An object that has already been detected can be measured a second time by a second measurement with a different wavelength.This allows the first measurement to be verified.

[0023] The wavelength range and / or the polarization direction of the emitted and received electromagnetic radiation can be matched. This is advantageously done in such a way that the receiving unit is sensitive to the wavelength range and / or the polarization direction of the emitted electromagnetic radiation.

[0024] In a further advantageous embodiment of the invention, the at least one transmitting unit is a laser. It can preferably be a one-dimensional laser bar or a two-dimensional laser matrix. A one-dimensional laser bar can consist of several laser diodes or transmitting lasers arranged in a linear arrangement, i.e., a row. In the two-dimensional laser matrix, several laser diodes are arranged in a matrix, i.e., in a two-dimensional arrangement. Furthermore, the at least one receiving unit is a linear detector array or a two-dimensional detector array. It can have several detection channels arranged in a linear arrangement, i.e., a row. Alternatively, the several detection channels can be arranged in a matrix, i.e., in a two-dimensional arrangement. The receiving unit is sensitive to electromagnetic radiation.The advantage of this design is that the use of laser bars or laser matrices and a linear or two-dimensional detector array enables optical resolution in an additional axis. The lidar sensor can include a one-dimensional laser bar and a linear detector array. The lidar sensor can include a one-dimensional laser bar and a two-dimensional detector array. The lidar sensor can include a two-dimensional laser matrix and a linear detector array. The lidar sensor can include a two-dimensional laser matrix and a two-dimensional detector array.

[0025] The optical resolution of the lidar sensor along the axis perpendicular to the rotational axis of the rotating unit can be achieved by rotating the unit itself. The optical resolution along the other axis can be achieved, for example, by aligning a laser bar and a linear detector array parallel to the rotational axis of the rotating unit. This allows the electromagnetic radiation to be emitted and received perpendicular to the rotational axis of the rotating unit. The individual laser diodes of the laser bar or laser matrix can be activated simultaneously or at different times. This allows for the creation of discretely adjustable beam angles. Simultaneously, the corresponding detection channel of a detector array or detector matrix for each laser diode can be activated.It is also possible to control the laser diodes and detection channels in such a way that measurements can be taken simultaneously from several angles.

[0026] In a further advantageous embodiment of the invention, the lidar sensor comprises at least two receiver units. One receiver unit is positioned in a first focal plane, and the other receiver unit is positioned in a second focal plane aligned parallel to the first. The two receiver units are arranged offset from each other by a predetermined distance along the orientation of the focal planes. The advantage of this embodiment is that the angular resolution of the lidar sensor can be doubled along one axis.

[0027] The invention also claims a method for controlling a lidar sensor for detecting an object in the environment. The lidar sensor comprises at least one transmitter unit for emitting electromagnetic radiation and at least one receiver unit for receiving electromagnetic radiation reflected from the object. The lidar sensor further comprises at least one refractive element, which is at least partially transparent to the electromagnetic radiation, and a rotating unit containing at least the at least one refractive element, the at least one transmitter unit, and the at least one receiver unit. The at least one refractive element further comprises at least one optical lens and a beam splitter for splitting the electromagnetic radiation, wherein two focal planes are provided.The at least one transmitting unit and the at least one receiving unit are positioned in at least one focal plane of at least one refractive element.

[0028] The control of the lidar sensor according to the invention can include the step of emitting electromagnetic radiation into the environment. By controlling the rotating unit, the electromagnetic radiation can be emitted into the environment in different directions or at different angles. By controlling different transmitting lasers of the transmitting unit, the electromagnetic radiation can be emitted into the environment in different directions or at different angles. The control of the lidar sensor can further include the step of receiving electromagnetic radiation from the environment. By controlling the rotating unit, electromagnetic radiation incident on the lidar sensor from different directions or at different angles can be selectively received by the receiving unit.By controlling different detection channels of the receiver unit, electromagnetic radiation incident on the lidar sensor from different directions or at different angles can be selectively received by the receiver unit. Controlling the lidar sensor can include a step to control at least one wavelength-selective component. Controlling the lidar sensor can include a step to control at least one polarization-selective component. Controlling the lidar sensor can include a step to control at least one polarization-changing component. For example, a polarization-selective component in the form of a liquid crystal retarder unit can be present in the lidar sensor. This can be controlled such that electromagnetic radiation of a predetermined polarization is reflected.This can also be controlled in such a way that electromagnetic radiation of a predetermined polarization is transmitted.

[0029] In an advantageous embodiment of the invention, a method for controlling a lidar sensor is provided, wherein the lidar sensor comprises at least two receiving units. The wavelength range and / or the polarization direction of the electromagnetic radiation received by the first receiving unit differs from the wavelength range and / or the polarization direction of the electromagnetic radiation received by the second receiving unit. The electromagnetic radiation is received such that electromagnetic radiation reflected by an object within a certain angular range is received in one step by one receiving unit and in another step by the other receiving unit.The advantage of this design is that an object located within the angular range of the lidar sensor can be detected by both receivers. Detection of an object by the first receiver can be verified by detection of the same object by the second receiver.

[0030] In an advantageous embodiment of the invention, a method for controlling a lidar sensor is provided, in which the electromagnetic radiation is received by the at least one receiving unit in a randomly determined temporal sequence at each angle of the angular range. Alternatively or additionally, the electromagnetic radiation can be emitted by operating the transmitting lasers of the transmitting unit in a randomly determined temporal sequence. The advantage of this embodiment is that random scan patterns can be realized. For example, the individual transmitting lasers of a transmitting unit can be controlled randomly. The control of the rotating unit can also be carried out in such a way as to realize random scan patterns.In a lidar sensor with two receivers, the rotating unit, as well as the first and second receivers, can be controlled such that the electromagnetic radiation is received alternately by the first and second receivers in a random sequence. An object within a certain angular range of the environment can be detected by the first receiver within a randomly determined number of measurement steps. Subsequently, the rotating unit can be controlled so that the same object within the same angular range of the environment is detected by the second receiver within a randomly determined number of measurement steps. The scan pattern can be made very flexible and unpredictable by randomly switching back and forth between the first and second receivers.Detecting ghost objects, for example those emitted by lasers located outside the lidar sensor, is significantly hampered. Varying the pulse rate at which the lidar sensor emits its electromagnetic radiation can further hinder or even prevent the detection of electromagnetic radiation from sources outside the lidar sensor. Drawings

[0031] An embodiment of the present invention will now be explained in more detail with reference to the accompanying drawings. The drawings show: Fig. 1 Lidar sensor with rotating unit, transmitter unit, receiver unit and an optical lens; Fig. 2 Lidar sensors with beam splitter as part of the refractive element; Fig. 3 possible spatial arrangements of the transmitting unit and the receiving unit; Fig. 4 further possibilities for the spatial arrangement of transmitting units and receiving units; Fig. 5 lidar sensors with beam splitter as part of the refractive element, as well as two receiver units and two transmitter units; Fig. 6 lidar sensors with beam splitter as part of the refractive element, two receiver units, two transmitter units and one liquid crystal retarder unit; Fig. 7 Methods for controlling a lidar sensor with two transmitting units and two receiving units; Fig. 8 Lidar sensor with beam splitter as part of the refractive element and two spatially separated transmitting units and receiving units each; Fig. 9 Lidar sensor with beam splitter as part of the refractive element, a transmitter unit and two spatially separated receiver units; Fig. 10 Lidar sensor with two refractive elements, each comprising an optical lens and a beam splitter; Fig. 11. Possibility of capturing the near range using a lidar sensor; Fig. 12 Lidar sensor with a holographic optical element as a beam splitter.

[0032] Fig. Figure 1 shows an example of the structure of a lidar sensor. This comprises a rotating unit 101 on which a transmitter 102, a receiver 103, and an optical lens 107 are located. The transmitter 102 and the receiver 103 are both located in the focal plane 109 of the optical lens 107. The transmitter 102 emits electromagnetic radiation 105. The electromagnetic radiation 105 passes through the optical lens 107 into the vicinity of the lidar sensor. In the vicinity, electromagnetic radiation 105 can be reflected by an object and subsequently received by the lidar sensor as electromagnetic radiation 106. The electromagnetic radiation 106 is then transmitted by the optical lens 107 and focused onto the focal plane 109 of the optical lens 107.The beam path of the emitted electromagnetic radiation 105 and the beam path of the received electromagnetic radiation 106 are positioned one above the other, i.e., coaxially arranged on a common optical axis. It may happen that the receiver 103 is only able to receive electromagnetic radiation 106, which was previously reflected by an object in the near range of the lidar sensor, in such a way that precise detection of the object can be achieved. The near range of the lidar sensor is, for example, the area extending up to a distance of 100 times the focal length of the optical lens 107 around the lidar sensor. With a focal length of the optical lens 107 of, for example, 2 cm, objects up to a distance of 2 m from the lidar sensor are within its near range.The difficulty in detecting an object at close range may be due to interference from the receiving unit 103 caused by portions of the electromagnetic radiation 105 emitted by the transmitting unit 102. To nevertheless detect objects in the vicinity of the lidar sensor, the lidar sensor may include a second receiving unit 104. The receiving unit 104 may be configured as a short-range detector or a short-range detector array. It may extract a portion of the received electromagnetic radiation 106.

[0033] Fig. Figure 2 shows an example of a lidar sensor on a rotating unit 101, in which the refractive element comprises an optical lens 107 and a beam splitter 201 for splitting the electromagnetic radiation. The beam splitter 201 provides two focal planes 109-1 and 109-2. The transmitting unit and the receiving unit are positioned in these two focal planes.

[0034] There are various possibilities for the spatial arrangement of the at least one transmitter unit 102 and the at least one receiver unit 103 in the lidar sensor. For example, the at least one transmitter unit 102 and the at least one receiver unit 103 can be positioned spatially separated from each other. The transmitter unit 102 can, for instance, be configured as a linear laser bar or a two-dimensional laser matrix, each composed of several laser diodes 102-1 to 102-x, where x denotes the number of laser diodes. The receiver unit 103 can, for example, be configured as a linear detector array or a two-dimensional detector matrix, each composed of several detection channels 103-1 to 103-y, where y denotes the number of detection channels. The spatial arrangement can also be such that a linear laser bar 102 and a linear detector array 103 have contacting interfaces.This creates a combination 204 of a transmitting unit 102 and a receiving unit 103, as shown in . Fig. Figure 3A shows another possible spatial arrangement of the at least one transmitting unit 102 and the at least one receiving unit 103. The laser diodes 102-1 to 102-x of the transmitting unit 102 and the detection channels 103-1 to 103-y of the receiving unit 103 are arranged together in a linear array. Such a combination 204 of a transmitting unit 102 and a receiving unit 103 is shown in Figure 3A. Fig. 3B shown.

[0035] In the Fig. In focal plane 109-1 shown in Figure 2, a transmitting unit 102 or a combination 204a consisting of a transmitting unit 102 and a receiving unit 103 can be positioned. In focal plane 109-2, a receiving unit 103 or a second combination 204b consisting of a transmitting unit 102 and a receiving unit 103 can be positioned. In the example shown, electromagnetic radiation 105 is emitted by the transmitting unit 102 or the combination 204a positioned in focal plane 109-1. For example, the emitted electromagnetic radiation 105 may be linearly polarized. The polarization-selective beam splitter 201 can be almost completely transparent to, for example, vertically linearly polarized electromagnetic radiation, as shown in the example. No energy is lost at the beam splitter 201 as the electromagnetic radiation 105 passes through it.In the example shown, the electromagnetic radiation 105 passes through an optical component 202, which affects the phase of the electromagnetic radiation. This component could, for example, be a λ / 4 plate, which in this example can convert the vertically linearly polarized electromagnetic radiation 105 into, for example, right-circularly polarized electromagnetic radiation 105. Furthermore, the electromagnetic radiation 105 can pass through an optical lens 107. It can also pass through an optical filter 203. In this example, the now, for example, right-circularly polarized electromagnetic radiation 105 is emitted into the vicinity of the lidar sensor. There, it can be scattered and / or reflected by an object. The electromagnetic radiation 106 scattered and / or reflected back by the object can be either polarized, partially polarized, or unpolarized.If the circularly polarized electromagnetic radiation 105 emitted in the example is reflected, for example, by a metallic object, it can undergo a phase shift of half a wavelength and subsequently become left circularly polarized. The backscattered and / or reflected electromagnetic radiation 106 can reach the lidar sensor. It passes, for example, through the optical filter 203 and can be refracted by the optical lens 107. If the electromagnetic radiation 106 passes through a component 202 again on its way to the receiver, the phase of the electromagnetic radiation 106 can be changed. In the example, left circularly polarized electromagnetic radiation 106 can be converted into horizontally linearly polarized electromagnetic radiation 106 by the λ / 4 plate 202. This can then be reflected by the beam splitter 201, which is reflective for horizontally linearly polarized electromagnetic radiation.It can be focused as electromagnetic radiation 106b onto the receiving unit 103 or the combination 204b located in the focal plane 109-2. Accordingly, it can be assumed that signals received by the receiving unit 103 or the combination 204b are caused by reflection from a metallic object. If, on the other hand, the emitted electromagnetic radiation 105 is reflected, for example, from a non-metallic object, the right-hand circular polarization can be reflected by the object as unpolarized light. In this example, the backscattered and / or reflected electromagnetic radiation 106 is not altered by the λ / 4 plate 202 and is subsequently split into two partial beams at the beam splitter 201.Part of the radiation can be focused as radiation 106a onto the combination 204a lying in the focal plane 109-1, and another part as radiation 106b onto the combination 204b lying in the focal plane 109-2.

[0036] In Fig. Figure 4 shows another possible spatial arrangement of a transmitting unit 102 and a receiving unit 103. For example, a lidar sensor can be a combination 204a in a focal plane 109-1 (see Figure 4). Fig. 3) and a combination 204b in a focal plane 109-2 (see Fig. 3) exhibit. The two combinations 204a and 204b can be aligned parallel to the axis of rotation of the rotating unit 101 and offset from each other by a distance 402 in the focal planes 109-1 and 109-2. The distance 402 can, for example, correspond exactly to half a bar pitch. A bar pitch can be understood as the central distance between the laser diodes of a laser bar or a laser matrix. A bar pitch can also be understood as the spatial extent of a laser diode along the axis of a one-dimensional laser bar or along an axis of a two-dimensional laser matrix. In Fig. Figure 4 shows, as an example, the bar pitch 401 of the laser diode 102-1 of the laser bar 102. By offsetting the two combinations 204a and 204b, the angular resolution along an axis parallel to the rotation axis of the rotating unit 101 can be doubled.

[0037] In Fig. Figure 5 shows a lidar sensor mounted on a rotating unit 101 with a beam splitter 201 as part of the refractive element, as well as two receiver units and two transmitter units. The two transmitter units and the two receiver units are each part of the two combinations 204a and 204b. Furthermore, in this embodiment, the lidar sensor has two optical lenses 107a and 107b. The first optical lens 107a can thus form a first refractive element together with the beam splitter 201. The optical lens 107a can refractively affect electromagnetic radiation that is emitted or received along the optical axis 108a of the optical lens 107a. The second optical lens 107b can form a second refractive element together with the beam splitter 201. The optical lens 107b can act refractively on electromagnetic radiation emitted or received along the optical axis 108b of the optical lens 107b.Due to the presence of the beam splitter 201, each of the two refractive elements has two focal planes. The first refractive element forms a first focal plane 109a-1 and a second focal plane 109a-2. The second refractive element forms a first focal plane 109b-1 and a second focal plane 109b-2. Since, in the example shown, the same beam splitter 201 is part of both refractive elements, the focal plane 109a-1 can be identical to the focal plane 109b-2, and vice versa. An optical filter 203a and / or an optical component 202a, which affects the phase of the transmitted electromagnetic radiation, can also be located along the optical axis of the optical lens 107a.Along the optical axis of the optical lens 107b, an optical filter 203b and / or an optical component 202b, which affects the phase of the transmitted electromagnetic radiation, may also be located. The arrangement of the various optical components along the optical axes can correspond to the arrangement shown in . Fig. 2 was shown. Alternatively, the one in Fig. The arrangement shown in section 5 can be selected. Compared to Fig. In version 2, the order of the optical components is different. Furthermore, the components are mounted very compactly. This eliminates many adjustment degrees of freedom through mechanical stops.

[0038] The two in Fig. The five combinations 204a and 204b shown can include laser diodes such that the wavelength of the electromagnetic radiation 105 emitted by the laser diodes of combination 204a differs from the wavelength of the electromagnetic radiation 105 emitted by the laser diodes of combination 204b. The optical filters 203a and 203b can each have a bandpass filter suitable for the different wavelengths. The detection channels of combinations 204a and 204b can be sensitive to both wavelengths of the received electromagnetic radiation 106. The detection channels of combinations 204a and 204b can each be sensitive to one of the two wavelengths of the received electromagnetic radiation 106. It is possible that the two combinations 204a and 204b have different sensitivities to the two wavelengths of the received electromagnetic radiation 106.With such a lidar sensor, measurements using electromagnetic radiation of two wavelengths can be performed simultaneously. These secondary measurements allow the presence of a detected object to be verified by measuring electromagnetic radiation of a second wavelength. Using electromagnetic radiation of different wavelengths can offer specific advantages and / or disadvantages, depending on the wavelength, for example, regarding atmospheric attenuation and / or the reflectivity of objects. Therefore, by using electromagnetic radiation of different wavelengths, more objects can be detected, potentially with higher accuracy.

[0039] The in Fig. The embodiment of a lidar sensor shown in 6 corresponds to the one in Fig. In the embodiment shown in Figure 5, the combination 204b is replaced by a receiving unit 103. Furthermore, a liquid crystal retarder unit 601 can be provided between the beam splitter 201 and the combination 204a. The liquid crystal retarder unit 601 can be controlled such that it affects the polarization of the electromagnetic radiation 105 emitted by the combination 204a. The polarization of the emitted electromagnetic radiation 105 can be adjusted so that it is transmitted by a polarization-selective beam splitter 201 and emitted into the environment along the optical axis 108a of the optical lens 107a. Alternatively, the polarization of the emitted electromagnetic radiation 105 can be adjusted so that it is reflected by the polarization-selective beam splitter 201 and emitted into the environment along the optical axis 108b of the optical lens 107b.

[0040] The previously mentioned possibility that an object located within an angular range in the vicinity of the lidar sensor can be detected by both the one and the other receiving unit is in Fig. 7 is described in more detail. The method shown there uses, for example, a lidar sensor as in Fig. 5 or Fig. 6. The lidar sensor can have two transmitting units, either as two transmitting units 102a and 102b or as part of two combinations 204a and 204b. The lidar sensor can also have two receiving units, either as two receiving units 103a and 103b or as part of two combinations 204a and 204b. For the sake of simplicity, in Fig. Figure 7 shows only one combination 204a and one combination 204b. In the illustrated embodiment, the lidar sensor can detect an angular range 701, which can be defined on one side by the limit 703 and on the other side by the limit 704. The angular range can be defined as shown in Fig. Figure 7 shows a range of 120°. However, the angular range can also be any other angle between 0° and 360°. The angular range can also be 360°. The detection of the angular range 701 can be achieved by controlling the rotating unit 101 such that electromagnetic radiation is emitted within the angular range 701. The lidar sensor can also receive electromagnetic radiation from the angular range 701. In the illustrated embodiment, in a first step, for example, electromagnetic radiation 105a of a first wavelength can be transmitted from a combination 204a by the beam splitter 201 and emitted along the optical axis 108a of the optical lens 107a. This step is illustrated in Figure 7. Fig. 7A. In the environment, electromagnetic radiation can be reflected by an object and subsequently received by the lidar sensor. Depending on the polarization and / or wavelengths, the electromagnetic radiation can be received, for example, by combination 204a or 204b. Subsequently, the rotating unit 101 can be controlled, for example, to rotate in the direction 702. The rotation can be such that, in the next step, electromagnetic radiation 105b of a second wavelength can be transmitted from the beam splitter 201 by combination 204b and emitted along the optical axis 108b of the optical lens 107b. In the environment, electromagnetic radiation can be reflected by an object and subsequently received by the lidar sensor. Depending on the polarization and / or wavelengths, the electromagnetic radiation can be received, for example, by combination 204a or 204b.

[0041] The emission of electromagnetic radiation in the second step can take place in the same direction or at the same angle within the angular range 701 as in the first step. In the exemplary embodiment, this would mean that the emitted electromagnetic radiation 105a or 105b is emitted parallel to the boundary 703 of the angular range 701 in both steps. Alternatively, the electromagnetic radiation 105b emitted in the second step can also be emitted as in Fig. 7B is shown at a different angle or in a different direction 705 within the angular range 701. The control of the rotating unit 101 can also be carried out such that the electromagnetic radiation is emitted and / or received in a randomly determined temporal sequence at each angle of the angular range. Alternatively or additionally, the individual transmitting lasers of each transmitting unit 102a and / or 102b can be operated in a randomly determined temporal sequence.

[0042] Fig. Figure 8 shows another embodiment of a lidar sensor. Similar to the one in Fig. 5 or Fig. As shown in Figure 6, the lidar sensor has a beam splitter 201, which is part of two refractive elements. In the exemplary embodiment of the Fig. Figure 8 of the lidar sensor comprises spatially separated transmitting units 102a and 102b and receiving units 103a and 103b. This spatial separation of the transmitting units 102a and 102b from the receiving units 103a and 103b prevents electromagnetic interference of the receiving units 103a and 103b caused by emitted electromagnetic radiation 105 from the transmitting units 102a and 102b. In this embodiment, the spatial separation can be achieved by having the beam splitter 201 have a larger spatial extent than the optical lenses 107a and 107b. Fig. Figure 8A shows how, for example, the electromagnetic radiation 105a can be emitted into the environment by the transmitting unit 102a. The received electromagnetic radiation 106a can, for example, be reflected at the beam splitter 201 and reach the receiving unit 103a. Fig. Figure 8B shows, for example, how electromagnetic radiation 105b can be emitted into the environment by the transmitting unit 102b. The received electromagnetic radiation 106b can, for example, be reflected at the beam splitter 201 and reach the receiving unit 103b. Both the emitted electromagnetic radiation 105a and 105b, as well as the received electromagnetic radiation 106a and 106b, can each have different wavelengths and / or polarizations.

[0043] In Fig. Figure 9 shows another embodiment of a lidar sensor. This sensor has a beam splitter 201 as part of a refractive element. It also has a transmitter 102 and two receivers 103a and 103b, which are spatially separated from the transmitter 102 and from each other. This spatial separation can again be advantageous in preventing electromagnetic interference with the receivers 103a and 103b. In this embodiment, the transmitter 102 is polarized in the direction indicated by the double arrow. The electromagnetic radiation 105 emitted by the transmitter 102 is reflected by the polarization-selective beam splitter 201 and emitted into the environment. Depending on the physical properties of an object in the environment from which the electromagnetic radiation is reflected, the polarization of the electromagnetic radiation can change as a result of the reflection.The receiving unit 103a can be configured to receive electromagnetic radiation 106a, which, upon striking the receiving unit 103a, is polarized in a direction indicated by the double arrow. In the exemplary embodiment, this polarization differs from that of the electromagnetic radiation 105 emitted by the transmitting unit 102. Electromagnetic radiation 106b, which, upon striking the receiving unit 103b, is polarized in a direction indicated by the double arrow positioned there, can be received by this receiving unit 103b. With such a lidar sensor, an object located within a certain angular range in the vicinity of the lidar sensor can be detected by both the receiving unit 103a and the receiving unit 103b. Here, too, a first measurement can be verified by a second measurement.

[0044] In Fig. Figure 10 shows another embodiment of a lidar sensor. This sensor has two refractive elements, each comprising an optical lens 107a or 107b and a beam splitter 201a or 201b, respectively. The transmitting unit 102a can emit electromagnetic radiation 105a, the polarization of which can differ from the polarization of the electromagnetic radiation 105b emitted by the transmitting unit 102b. Furthermore, the lidar sensor has two transmitting units 102a and 102b and two receiving units 103a and 103b, which are spatially separated from the transmitting units 102a and 102b, as well as from each other. This spatial separation can again be advantageous in order to avoid electromagnetic interference with the receiving units 103a and 103b.With such a lidar sensor, an object located within an angular range in the vicinity of the lidar sensor can be detected by both the one receiving unit 103a and the other receiving unit 103b.

[0045] Fig. Figure 11 shows another possibility for detecting the near range using a lidar sensor. Electromagnetic interference from a transmitter 102 positioned close to a receiver 103 is possible. This can be achieved by utilizing so-called self-mixing interference in the transmitter 102. The transmitter 102 can be configured as a surface emitter (VCSEL, vertical-cavity surface-emitting laser).

[0046] Fig. Figure 12 shows an embodiment of a lidar sensor with a holographic optical element 1201 as a beam splitter. As described in the other embodiments, the lidar sensor has a rotating unit 101. A receiver unit 102 is located on this unit and is positioned in one focal plane 109-1 of the refractive element. A receiver unit 103 is positioned in a second focal plane 109-2. Alternatively, combinations 204a and / or 204b of a transmitter unit and a receiver unit can be positioned in one and / or both focal planes. In this embodiment, the refractive element is formed from an optical lens 107 with a holographic optical element 1201. An angle 1202 is formed between the surface of the holographic optical element 1201 and the optical axis 108 of the optical lens 107. The holographic optical element 1201 can be polarization-selective.It can be composed of a stack of transmissive holographic optical elements for a first polarization and a reflection holographic optical element for a second polarization. Alternatively, anisotopic holographic materials can also be used to form the holographic optical element 1201. In this case, it is possible that only a defined polarization of the electromagnetic radiation is diffracted at the holographic optical structure at any given time. The lidar sensor can include an optical component 202 that affects the phase of the transmitted electromagnetic radiation. The effect of the individual optical elements on the emitted electromagnetic radiation 105 and the received electromagnetic radiation 106 corresponds to the effects of the optical elements described in the previous embodiments.It is also possible that the positions of the transmitting unit 102 and the receiving unit 103 are reversed. The receiving unit 102 can also be positioned in the second focal plane 109-2, with the receiving unit 103 then positioned in the focal plane 109-1. This can be advantageous if the diffraction efficiency of the holographic optical element 1201 is not 100%. In this case, the electromagnetic radiation 105 emitted by the transmitting unit 102 is not 100% diffracted by the holographic optical element 1201 and emitted into the environment. This loss can be compensated for by a higher power output of the transmitting unit 102. In this example, the lower diffraction efficiency would not have a negative effect on the receiving path, but rather a positive one. The received electromagnetic radiation 106 can be efficiently transmitted through the holographic optical element 1201.

[0047] In Fig. Figure 12A shows an embodiment in which the transmitter unit 102 is positioned on the optical axis 108 of the optical lens 107. This can be described as an inline geometry. Since holographic optical elements can be represented with different angles of incidence and reflection, other designs can also be implemented. For example, the transmitter unit 102 is shown in the Fig. In the embodiment shown in Figure 12B, the optical lens 107 is not positioned on the optical axis 108, but rather offset from it on the focal plane 109-1. This can be described as an off-axis design. The angle 1202 of the Fig. The embodiment shown in 12B differs from the angle 1202 of the one shown in Fig.The embodiment shown in Figure 12A is shown. Additionally, the position of the receiver unit 103 can also be selected differently. The optical lens 107 can be optional in the illustrated embodiments. Its function can also be taken over by the polarization-selective holographic optical element 1201. For this purpose, the holographic optical element 1201 itself can have a focusing function. The holographic optical element 1201 can also have wavelength selectivity. This allows it to also have a filter function and, depending on the exact design of the lidar sensor or the measurement application, replace the optical filter 203.

Claims

[1] Lidar sensor for detecting an object in the environment comprising • at least one transmitting unit (102, 102a, 102b, 204, 204a, 204b) for emitting electromagnetic radiation (105, 105a, 105b), • at least one receiving unit (103, 103a, 103b, 204, 204a, 204b) for receiving electromagnetic radiation (106, 106a, 106b) reflected from the object, • at least one refractive element which is at least partially transparent to electromagnetic radiation (105, 105a, 105b, 106, 106a, 106b), • a rotating unit (101) containing at least one refractive element, at least one transmitting unit (102, 102a, 102b, 204, 204a, 204b) and at least one receiving unit (103, 103a, 103b, 204, 204a, 204b), characterized by , that • the at least one refractive element comprises at least one optical lens (107, 107a, 107b) and a beam splitter (201, 201a, 201b, 1201) for splitting the electromagnetic radiation (105, 105a, 105b, 106, 106a, 106b), wherein two focal planes (109, 109-1, 109-2, 109a-1, 109a-2, 109b-1, 109b-2) are present, and that • that at least one transmitting unit (102, 102a, 102b, 204, 204a, 204b) and at least one receiving unit (103, 103a, 103b, 204, 204a, 204b) are positioned in at least one focal plane (109, 109-1, 109-2, 109a-1, 109a-2, 109b-1, 109b-2) of at least one refractive element, and that • the lidar sensor comprises at least two receiver units (103a, 103b, 204a, 204b), wherein • a receiving unit (103a, 204a) is positioned in a first focal plane (109a-1, 109b-2) and wherein • the other receiving unit (103b, 204b) is positioned in a second focal plane (109b-1, 109a-2) aligned parallel to the first focal plane (109a-1, 109b-2), and wherein • the two receiving units are arranged offset from each other by a predetermined distance (402) along the orientation of the focal planes (109-1, 109-2, 109a-1, 109a-2, 109b-1, 109b-2). [2] Lidar sensor according to claim 1, characterized by , that the beam splitter (201, 201a, 201b, 1201) splits the electromagnetic radiation (105, 105a, 105b, 106, 106a, 106b) in a polarization-selective and / or wavelength-selective manner. [3] Lidar sensor according to one of claims 1 or 2, characterized by , that in a beam path of the transmitting unit (102, 102a, 102b, 204, 204a, 204b) and / or the receiving unit (103, 103a, 103b, 204, 204a, 204b) further wavelength-selective and / or polarization-selective and / or polarization-changing components (202, 202a, 202b, 203, 203a, 203b, 601) are provided. [4] Lidar sensor according to one of claims 1 to 3, characterized by , that the beam splitter is formed by a polarization-selective and / or wavelength-selective holographic element (1201). [5] Lidar sensor according to any one of claims 1 to 4, characterized by , that the at least one transmitting unit (102, 102a, 102b, 204, 204a, 204b) is designed to emit electromagnetic radiation (105, 105a, 105b) of a selective wavelength range and / or a selective polarization direction. [6] Lidar sensor according to claim 5, characterized by, that the lidar sensor comprises at least two transmitting units (102a, 102b, 204a, 204b) and wherein the wavelength range and / or the polarization direction of the emitted electromagnetic radiation (105a) of the first transmitting unit (102a, 204a) differs from the wavelength range and / or the polarization direction of the emitted electromagnetic radiation (105b) of the second transmitting unit (102b, 204b). [7] Lidar sensor according to any one of claims 1 to 6, characterized by , that the at least one receiving unit (103, 103a, 103b, 204, 204a, 204b) is designed to receive electromagnetic radiation (106, 106a, 106b) of a specific wavelength range and / or a specific polarization direction. [8] Lidar sensor according to claim 7, characterized by, that the lidar sensor comprises at least two receiving units (103a, 103b, 204a, 204b) and wherein the wavelength range and / or polarization direction of the electromagnetic radiation (106a) received by the first receiving unit (103a, 204a) differs from the wavelength range and / or polarization direction of the electromagnetic radiation (106b) received by the second receiving unit (103b, 204b). [9] Lidar sensor according to one of claims 1 to 8, characterized by , that • the at least one transmitting unit (102, 102a, 102b, 204, 204a, 204b) a laser, preferably a laser bar or a laser matrix, and • which at least one receiving unit (103, 103a, 103b, 204, 204a, 204b) is a linear detector array or a 2-dimensional detector array. [10] Method for controlling a lidar sensor to detect an object in the environment, wherein the lidar sensor comprises • at least one transmitting unit (102, 102a, 102b, 204, 204a, 204b) for emitting electromagnetic radiation (105, 105a, 105b), • at least one receiving unit (103, 103a, 103b, 204, 204a, 204b) for receiving electromagnetic radiation (106, 106a, 106b) reflected from the object, • at least one refractive element which is at least partially transparent to electromagnetic radiation (105, 105a, 105b, 106, 106a, 106b), • a rotating unit (101) containing at least one refractive element, at least one transmitting unit (102, 102a, 102b, 204, 204a, 204b) and at least one receiving unit (103, 103a, 103b, 204, 204a, 204b), characterized by , that • the at least one refractive element comprises at least one optical lens (107, 107a, 107b) and a beam splitter (201, 201a, 201b, 1201) for splitting the electromagnetic radiation (105, 105a, 105b, 106, 106a, 106b), wherein two focal planes (109, 109-1, 109-2, 109a-1, 109a-2, 109b-1, 109b-2) are present, and that • that at least one transmitting unit (102, 102a, 102b, 204, 204a, 204b) and at least one receiving unit (103, 103a, 103b, 204, 204a, 204b) are positioned in at least one focal plane (109, 109-1, 109-2, 109a-1, 109a-2, 109b-1, 109b-2) of at least one refractive element, and that • the lidar sensor comprises at least two receiver units (103a, 103b, 204a, 204b), wherein • a receiving unit (103a, 204a) is positioned in a first focal plane (109a-1, 109b-2) and wherein • the other receiving unit (103b, 204b) is positioned in a second focal plane (109b-1, 109a-2) aligned parallel to the first focal plane (109a-1, 109b-2), and wherein • the two receiving units are arranged offset from each other by a predetermined distance (402) along the orientation of the focal planes (109-1, 109-2, 109a-1, 109a-2, 109b-1, 109b-2). [11] Method according to claim 10, characterized by , that • the lidar sensor comprises at least two receiving units (103a, 103b, 204a, 204b) according to claim 8, and that • the reception of the electromagnetic radiation (106a, 106b) is carried out in such a way that electromagnetic radiation (106a, 106b) reflected by an object within an angular range (701) is received in one step by one receiving unit (103a, 204a) and in another step by the other receiving unit (103b, 204b). [12] Method according to claim 10 or 11, characterized by, that • the reception of the electromagnetic radiation (106, 106a, 106b) is such that the electromagnetic radiation (106, 106a, 106b) is received in a randomly determined temporal sequence under each angle (705) of the angular range (701) by the at least one receiving unit (103, 103a, 103b, 204, 204a, 204b) and / or that • the emission of the electromagnetic radiation (105, 105a, 105b) is carried out in such a way that the transmitting lasers (102-1, 102-2, 102-3, 102-4) of the transmitting unit (102, 102a, 102b, 204, 204a, 204b) are operated in a randomly determined temporal sequence.

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