OPTICAL SCANNER

Abstract

The invention relates to an optical scanner for detecting objects in a monitoring area, comprising a two-dimensional scanner, a light transmitter for emitting a pulsed beam of light into the monitoring area, a detector for detecting light pulses reflected from an object in the monitoring area, and a continuously rotatable rotating mirror for pivoting the direction of transmission of the beam of light over a polar angle, a continuously rotatable rotor on which at least the light transmitter, the detector, and the rotating mirror are arranged for pivoting the direction of transmission of the beam of light over an azimuthal angle, a stator relative to which the rotor is rotatable about an axis of rotation, and a control and evaluation unit.The optical scanner is characterized by the fact that an optical separation device is arranged between the light transmitter and the detector to suppress optical crosstalk from the light transmitter to the detector, and by a device for contactless transmission of data and energy between the rotor and the stator.

Description

[0001] The invention relates to an optical scanner according to the preamble of claim 1.

[0002] A generic optical scanner based on the time-of-flight principle for detecting objects in a monitored area comprises, firstly, a two-dimensional scanner with a light source for emitting a pulsed beam of light into the monitored area, a detector for detecting light pulses reflected back from an object in the monitored area, and a continuously rotatable mirror for pivoting the direction of the transmitted light beam across a polar angle. Furthermore, the generic optical scanner includes a continuously rotatable rotor on which at least the light source, the detector, and the mirror are arranged for pivoting the direction of the transmitted light beam across an azimuthal angle, as well as a stator relative to which the rotor is rotatable about an axis of rotation.Furthermore, the generic optical scanner has a control and evaluation unit which is set up to control the light transmitter, to evaluate light pulses detected by the detector and to determine an object distance of the object relative to the optical scanner based on the travel time of light pulses detected at a certain orientation of the transmitted light beam, wherein the orientation is given by the respective set polar angle and azimuthal angle.

[0003] Numerous technical solutions exist for optical object detection in three-dimensional (3D) space through the implementation of swiveling two-dimensional (2D) measurement systems. Such systems utilize existing 2D sensors, including light section sensors, camera sensors, or 2D laser scanners, mounted on a motion unit. Continuous 2D measurement by the sensor system, combined with the linear or rotational displacement of the measurement unit, enables partial 3D object measurement, i.e., scanning of the observation space. These systems are also known as swivel sensors. Depending on the design, these systems offer varying performance in terms of range, angle, and spatial resolution. A common feature of all these systems is the significant complexity involved in the appropriate integration of one or more motor units, data and power supply, the sensors, and the evaluation systems.

[0004] One object of the invention can be seen as being to design and constructively connect the units necessary for 3D measurement in a suitable manner, resulting in a small and compact size and thus a cost-effective solution.

[0005] This problem is solved by the optical scanner with the features of claim 1.

[0006] The optical scanner of the type described above is further developed according to the invention in that an optical separation device is arranged between the light transmitter and the detector to suppress optical crosstalk from the light transmitter to the detector, and is further characterized by a device for contactless transmission of data and energy between the rotor and the stator.

[0007] Preferred embodiments of the optical scanner according to the invention are explained below, particularly in connection with the dependent claims and the figures.

[0008] Optical scanners are devices used to scan or probe objects and / or a spatial area. Such scanners and methods for their operation are known, for example, from WO 2012 / 163515 A1. Optical scanners that scan space in a plane are referred to as two-dimensional (2D).

[0009] The term time-of-flight principle refers to methods for operating optical scanners in which, using the speed of light in the relevant medium, usually air, a distance to a detected object is determined by measuring the time of flight of the transmitted light, in particular transmitted light pulses, from the optical sensor to the object and back to the detector.

[0010] In principle, the scanner according to the invention can detect any objects in a monitoring area that reflect the transmitted light strongly enough, which generally does not pose a practical limitation.

[0011] The monitoring area is defined as the area of ​​space in which objects can be detected. The size of the monitoring area is limited, in particular, by the power of the light transmitter, i.e., by the energy of the light pulses, and by the performance of the detector.

[0012] Semiconductor light sources, especially semiconductor lasers, are typically used as light emitters, particularly in the infrared range. Light emitters in the visible and ultraviolet ranges can also be used. A suitable transmitting optic can be advantageous for generating a collimated beam of light.

[0013] Semiconductor detectors, such as CCD, CMOS and / or SPAD detectors, are generally used as detectors.

[0014] A pulsed light beam is a light beam that emits light not continuously, but in individual pulses. These pulses can range from a few nanoseconds (ns) to a few microseconds (µs). The number of pulses emitted per second depends heavily on the specific application and the light source used. Typically, the pulse repetition rate ranges from a few kilohertz (kHz) to several megahertz (MHz).

[0015] Backscattered light pulses are those light pulses that are reflected or scattered back from an object in the monitored area.

[0016] A rotating mirror is a mirror that can rotate around an axis of rotation. Such a mirror is described as continuously rotatable if this rotation is possible continuously in the same direction, in contrast to rotating mirrors that can only be pivoted through a specific angular range.

[0017] The rotor is a mechanical device that rotates continuously relative to the stator, i.e., continuously in the same direction. The stator is the mechanical device that remains stationary relative to its immediate surroundings during the intended operation of the optical sensor. Motors are provided to drive both the rotor and the rotating mirror. The rotor and the rotating mirror can each rotate at speeds between 10 Hz and 100 Hz. Regarding the technology of arranging the transmitter and detector on a rotor, reference is made to the prior art described above and the references therein.

[0018] The terms polar angle and azimuthal angle refer specifically to the rotor's axis of rotation. The polar angle is the angle relative to this axis. The azimuthal angle is the angle of deflection relative to an axis perpendicular to the rotor's axis of rotation, for example, relative to the x-axis. The polar angle and the azimuthal angle uniquely define an orientation in space relative to the axis of rotation (spherical coordinates).

[0019] The control and evaluation unit may preferably have at least one programmable logic component, for example a microcontroller or an FPGA, or be formed by such a component.

[0020] The present invention combines three essential concepts. First, a two-dimensional scanner, known as such, is arranged on a rotor. Furthermore, the two-dimensional scanner is provided with an optical isolation device to prevent interference from the light source affecting the received signal measured by the detector. Finally, the invention includes means for the contactless transmission of both data and energy between the rotor and the stator.

[0021] The invention is based first on the understanding that laser pulse time-of-flight sensors (LiDAR), which achieve the highest spatial resolution in distance and angle with very small light spots, offer the highest precision and reliability for object detection. Secondly, the invention is based on the understanding that transmitter, receiver, optics, and evaluation modules can be combined into a small, compact measuring system.

[0022] A key advantage of the invention is that an optical sensor with a small and compact design can be implemented cost-effectively, while simultaneously offering very good and reliable measurement performance over a large range.

[0023] The rotor's axis of rotation is preferably perpendicular to the axis of rotation of the rotating mirror. This allows the polar angle and the azimuthal angle to be varied independently of each other.

[0024] Preferably, the direction of the transmitted light arriving at the rotating mirror in the transmitting beam path is perpendicular to the axis of rotation of the rotating mirror or perpendicular to a projection of the axis of rotation of the rotating mirror into a plane in which the direction of the transmitted light arriving at the rotating mirror in the transmitting beam path lies. Such arrangements are preferred with regard to achieving the largest possible polar angle, because shadowing by the transmitter can be reduced.

[0025] In order to assign the measurement data collected at a specific time to the respective orientation of the transmitting beam in space, it may be preferred that the control and evaluation unit is also equipped to control the rotating mirror and / or the rotor and / or to read out a momentary rotational position of the rotating mirror and / or the rotor.

[0026] Parts of the control and evaluation unit can be located on the rotor, and other parts of the evaluation unit can be located on the stator. It is particularly advantageous for those parts of the control and evaluation unit that perform the actual determination of the transit time—i.e., controlling the light transmitter and determining the reception time with any necessary corrections and compensations—to be located near the two-dimensional optical scanner, and especially preferably on the rotor, in particular on a circuit board that acts as an optical separator.

[0027] The optical separation device can have at least one partition that is opaque to the transmitted light or be formed by such a partition.

[0028] The partition, the light transmitter, the detector and the rotating mirror are preferably arranged relative to each other in such a way that light reflected from an object in the monitored area cannot reach the detector via the rotating mirror.

[0029] The axis of rotation of the rotor can preferably lie in one of the planar extension directions of the partition.

[0030] In principle, the partition can be a separate component. Particularly small designs of the optical scanner according to the invention can be achieved if the partition is implemented as a circuit board. Further components can then be arranged on this circuit board.

[0031] In a particularly preferred embodiment, the partition, especially the circuit board, extends essentially perpendicular to the stator and, in particular, almost to the inner housing wall. This enables particularly good optical separation between the transmitter and receiver sides. If the upper housing part has at least a partial spherical shape, the partition can accordingly have a circular outer contour at its upper edge in this area. A gap between the inner housing wall and the partition can then, for example, have a width on the order of 1 mm.

[0032] A drive, in particular an electric motor, is provided to drive the rotating mirror. Particularly small designs of the optical scanner according to the invention can be realized if a motor integrated into the optical separation device is provided to drive the rotating mirror.

[0033] Preferably, at least one coil of the motor can be formed on the circuit board. Such motors can be implemented in a very small form factor and are also referred to as circuit board motors.

[0034] The device for contactless energy and data transmission can advantageously include a data light barrier. To provide the functionality of the optical scanner according to the invention, it is sufficient if data can be transmitted from the two-dimensional optical scanner on the rotor to the stator. In advantageous embodiments of the optical scanner according to the invention, the data light barrier is configured for bidirectional data transmission. This means, for example, that settings of the two-dimensional scanner can be changed via the data light barrier. For bidirectional data transmission with a data light barrier, it can be provided, for example, that data is transmitted from the rotor to the stator using light of a first wavelength, and data is transmitted from the stator to the rotor using light of a second wavelength, which differs from the first wavelength.

[0035] In an alternative design, contactless data transmission is achieved unidirectionally or bidirectionally using microwaves, particularly polarized microwaves. Microwaves can achieve transmission rates of 100 Mbit / s and more.

[0036] The rotor can advantageously be connected to the stator via a hollow shaft, wherein, in particular, a transmission path of one or more data light barriers runs within the hollow shaft. The optical hollow shaft can be designed such that optically separate channels for optical data transmission can be installed within it. At least one optical fiber, for example, a fiber optic cable, can be provided within the hollow shaft for optical data transmission.

[0037] In principle, it would also be possible to optically transfer energy from the stator to the rotor. However, in preferred embodiments of the optical scanner according to the invention, the energy transfer takes place inductively, i.e., the device for contactless data and energy transmission has a transformer section between the rotor and the stator.

[0038] In principle, it is sufficient for the rotating mirror to have a single reflective surface. In advantageous embodiments of the scanner according to the invention, the rotating mirror is implemented as a double mirror or a polygon mirror. For example, the rotating mirror can be a three-sided polygon mirror. A four-sided polygon mirror is particularly preferred as the rotating mirror.

[0039] In a further particularly preferred embodiment, the rotating mirror is arranged relative to the light source such that, in at least one rotational position of the rotating mirror, the direction of transmission of the transmitted light beam from the light source is tangential to a mirror surface of the rotating mirror. This measure minimizes shadowing caused by the mirror itself, thus enabling a large polar angle to be achieved.

[0040] To direct the light reflected from the monitored area as effectively as possible to the detector, a light-collecting optical system can be positioned upstream of the detector. Particularly preferred configurations are characterized by the inclusion of a rotating mirror in the detection beam path upstream of the detector. This rotating mirror can, in principle, be of the same type as the rotating mirror in the transmitting beam path. For example, a four-sided polygonal mirror can also be used as the rotating mirror in the detection beam path. Advantageously, the rotating mirror in the detection beam path can be driven by the same drive mechanism as the rotating mirror in the transmitting beam path.

[0041] In a further particularly preferred embodiment, the rotating mirror in the detection beam path is arranged relative to the detector such that, at least in one rotational position of the rotating mirror in the detection beam path, one direction of the beam of reflected light coming from the monitored area is tangential to a mirror surface of the rotating mirror in the detection beam path. This feature again serves to avoid shadowing and to achieve the largest possible polar angle.

[0042] The optical scanner can have a housing in which the rotor and stator are located. The housing can advantageously include a dome-shaped housing section made of a material transparent to the transmitted light. To ensure that the dome-shaped housing section does not restrict the achievable solid angle, the opening angle of the dome-shaped housing section is selected to be at least as large as the solid angle achievable for the transmitted beam when the two-dimensional scanner and the rotor interact. For example, if the polar angle deviation is π / 2 (corresponding to 90°), the opening angle of the dome-shaped housing section is selected to be large enough that transmitted light can exit into the monitoring area and light reflected from a detected object can enter the monitoring area within a solid angle of at least 2π. The dome-shaped housing section can preferably have the form of a partial spherical shell with constant thickness.This achieves the advantage that the travel time of the transmitted and received light through the dome-shaped housing section is essentially independent of the orientation of the transmitted light beam (polar angle, azimuth angle). Furthermore, reflections of the transmitted and received light can be minimized. When it is stated here that the housing section partially has the shape of a spherical shell or a partial spherical shell, this means that the housing section has the shape of a spherical shell in the area where transmitted light can exit the housing and received light can enter it.

[0043] Further advantages and features of the invention are explained below in connection with the accompanying figures. These show: Fig. 1: a front view of a first embodiment of an optical scanner according to the invention; Fig. 2: A view from the rear of the optical scanner Fig. 1; Fig. 3: A top view of the optical scanner Fig. 1; Fig. 4: a first partial view of a second embodiment of an optical scanner according to the invention; Fig. 5: a second partial view of the optical scanner from Fig. 4; Fig. 6: a partial view of an embodiment of an optical scanner according to the invention to illustrate the relative arrangement of the light source and the rotating mirror in the transmitting beam path; and Fig. 7: a partial view of an embodiment of an optical scanner according to the invention to illustrate the relative arrangement of the detector and a rotating mirror in the detection beam path.

[0044] Identical and equivalent components are generally marked with the same reference symbols in the figures.

[0045] A first embodiment of an optical scanner 100 according to the invention is described with reference to the Fig. 1 to 3 explained. Fig. Figure 1 shows a schematic front view of the optical scanner 100 according to the invention, which operates according to the time-of-flight principle and is intended to detect objects in a monitoring area 70 and to measure distances to these objects. An object A is in the Fig. 1 and Fig. 2 schematically represented. Fig. Figure 2 shows a rear view of the optical scanner 100 and Fig. Figure 3 shows a top view of the optical scanner 100.

[0046] The optical scanner 100 initially comprises a two-dimensional scanner 40 with a light transmitter 15 for emitting a pulsed transmitting light beam 12 into the monitoring area 70, a detector 50 for detecting light pulses 14 reflected back from the object A in the monitoring area 70, and a continuously rotatable rotating mirror 41 for pivoting the transmitting light beam 12 by a polar angle Θ. The plane that the two-dimensional scanner 40 scans lies in the drawing plane of the Fig. 1 and Fig. 2. In the illustrated embodiment, a motor is provided to drive the rotating mirror 41, which is located in the Fig. 1 and Fig. 2 is not shown.

[0047] Furthermore, the optical scanner 100 according to the invention has a continuously rotatable rotor 20 on which at least the light emitter 15, the detector 50, and the rotating mirror 41 are arranged for pivoting the direction of transmission of the transmitted light beam 12 over an azimuthal angle φ. A stator 10 is also provided, relative to which the rotor 20 is rotatable about an axis of rotation 21. A drive is provided for driving the rotor 20, which is not shown in the figures. During intended use of the optical scanner 100, the stator is at rest relative to at least its immediate surroundings and is, for example, mounted on a surface. In the illustrated embodiment, the axis of rotation 21 of the rotor 20 is perpendicular to the axis of rotation 22 of the rotating mirror 41.

[0048] One direction of rotation of the rotor 20 is in the Fig. 1 to 3 are each schematically indicated by a curved arrow φ.

[0049] The polar angle Θ is, as can be seen from the Fig. 1 and Fig. As can be seen in Figure 2, the angle that the beam direction makes relative to the axis of rotation 21 of the rotor 20 is the azimuthal angle φ. The azimuthal angle φ is the angle that a projection of the beam direction into a plane perpendicular to the axis of rotation 21 makes relative to an axis in that plane. If, as is usual, a coordinate system is chosen such that the axis of rotation 21 lies on the z-axis, the azimuthal angle φ can, for example, be measured against the x-axis.

[0050] Furthermore, the optical scanner 100 according to the invention has a feature in the Fig. 1 and Fig. Figure 2 schematically depicts a control and evaluation unit 80, which is configured to control the light transmitter 15, to evaluate light pulses 14 detected by the detector 50, and to determine the object distance of object A relative to the optical scanner 100 based on the travel time of light pulses detected at a specific orientation of the transmitted light beam 12. The orientation of the transmitted light beam 12 is determined by the respective set polar angle Θ and azimuthal angle φ. In the illustrated embodiment, the control and evaluation unit 80 is also configured to control the rotating mirror 41 and the rotor 20 and to read out the instantaneous rotational position of the rotating mirror 41 and the rotor 20.

[0051] Furthermore, in the optical scanner 100 according to the invention, an optical isolation device 42 is arranged between the light transmitter 15 and the detector 50 to suppress optical crosstalk from the light transmitter 15 to the detector 50, and finally, a device 60 for contactless transmission of data and energy between the rotor 20 and the stator 10 is provided. The device 60 for contactless transmission of energy and data can include a data light barrier, in particular a bidirectional one. For contactless transmission of energy between the rotor 20 and the stator 10, a transformer section can be formed between the rotor 20 and the stator 10.

[0052] In the illustrated embodiment, the optical separating device 42 has a partition that is opaque to the transmitted light 12. As can be seen from the Fig. As can be seen in Figures 1 to 3, the partition 42, the light transmitter 15, the detector 50 and the rotating mirror 41 are arranged relative to each other in such a way that light 14 reflected from the object A in the monitoring area 70 cannot reach the detector 50 via the rotating mirror 41.

[0053] In the illustrated embodiment, as shown, the process unfolds as follows: Fig. 3 shows a direction of the transmitted light 12 arriving at the rotating mirror 41 in the transmitting beam path perpendicular to the axis of rotation 22 of the rotating mirror 41 or perpendicular to a projection of the axis of rotation 22 of the rotating mirror 41 in a plane in which lies the direction in which the transmitted light 12 hits the rotating mirror 41.

[0054] In the Fig. In the embodiment shown in Figures 1 to 3, the schematically depicted rotating mirror 41 in the transmitting beam path is a double mirror, i.e., a mirror with a reflective front and a reflective back. In the embodiment of Fig. In the detection beam path upstream of detector 50, a rotating mirror 44, which is also a double mirror, is present in steps 1 to 3. This rotating mirror 44 can be fixedly connected to the rotating mirror 41 in the transmitting beam path and can therefore be driven by the same drive as the rotating mirror 41. Instead of the double mirrors, polygon mirrors, for example three- or four-sided polygon mirrors, can also be used for the rotating mirrors 41 and 44.

[0055] A second embodiment of an optical scanner 200 according to the invention is now described with reference to the Fig. 4 and Fig. 5 explained. Fig. Figure 4 shows the arrangement of the components according to the invention and further details of the optical scanner 200. Fig. Figure 5 shows the optical scanner 200 in a standard measurement situation. Only those components that differ from the optical scanner 100 are described here. Fig. Distinguish between 1 and 3.

[0056] The optical scanner 200 features a four-sided polygon mirror 41a as a rotating mirror in the transmitting beam path. A similarly four-sided polygon mirror 44a is arranged in the detection beam path on the same drive shaft as the rotating mirror 41a. The mirrors 41a and 44a can be of the same design.

[0057] The optical separation device 42 in the optical scanner 200 is formed by a circuit board located between the transmitter side with the light emitter 15 and the receiver side with the detector 50. A motor 45, integrated into this circuit board 42 and shown schematically, is provided in the optical scanner 200 to drive the rotating mirrors 41a, 44a. At least one coil of the motor 45 is formed on or within the circuit board 42. The axis of rotation 22 of the rotating mirrors 41a, 44a is perpendicular to the z-direction and thus perpendicular to the axis of rotation of the rotor 20. Parts of the control and evaluation unit 80 are arranged on the circuit board 42. This could, for example, be a preamplifier for the detector 50.

[0058] Further parts of the control and evaluation unit 80 are arranged on the stator 10. Also located on the stator 10 (schematically shown) are a communication interface 81, via which the optical scanner 200 can be connected to a higher-level control system, for example, and a power supply 82.

[0059] The device for contactless data and energy transmission, in the exemplary embodiment of the Fig. 4 and Fig. 5 a schematically represented energy transmission unit 83, which is a transformer section formed between the stator 10 and the rotor 20, and a data transmission unit 84, in particular bidirectional, which, as in the embodiment of the Fig. 1 to 3 are formed as a data light barrier. The planes of the rotor and the stator each extend essentially in the xy-plane. The direction of rotation of the rotor 20 is again represented by a curved arrow φ.

[0060] A hollow shaft (without reference numeral) is formed between the rotor 20 and the stator 10, with the data light barrier running inside this hollow shaft. This ensures trouble-free operation of the data light barrier.

[0061] In the Fig. In the situation shown in section 5, an object A to be detected is located in the monitoring area 70. Light pulses 12 emitted by the light transmitter 15 reach the monitoring area 70 via the polygon mirror 41a and, as shown in Fig. Figure 5 illustrates how, with a suitable rotation of the rotating mirror 41a, the light pulses 14 directed towards object A are focused. Light pulses 14 reflected from object A strike the polygonal mirror 44a and are guided via this mirror to the detector 50. Direct crosstalk from the transmitted light 12 to the receiving side and thus to the detector 50 is prevented by the optical separation device 42 (see Figure 5). Fig. 4, in Fig. (5 not shown) prevents. The control and evaluation unit 80 is designed to determine the travel time of the light pulses and to calculate the distance of object A as a function of the current orientation of the transmitted light beam 12. The orientation of the transmitted light beam is given by the polar angle θ that the transmission direction makes with respect to the z-axis, and by the azimuthal angle that a projection of the transmission direction into the xy-plane makes relative to the x-axis.

[0062] The optical scanner 200 has a housing (not shown in detail) in which the rotor 20 and the stator 10 are located. This housing has a dome-shaped housing section made of a material transparent to the transmitted light 12, which is not shown in the figures. Through the dome-shaped housing section, transmitted light 12 can exit into the monitoring area 70 at a solid angle of at least 2π, and backscattered light 14 from an object A to be detected can penetrate into the interior of the housing from the monitoring area 70 at a solid angle of at least 2π. The dome-shaped housing section has the form of a spherical shell with constant thickness (not shown in the figures). A meridian of this spherical shell is denoted by M, and a latitude, thus a line of points with a constant polar angle θ, is denoted by Fig. 5 marked with the letter B.

[0063] Preferred arrangements of the transmitter 15 relative to the rotating mirror in the transmitting beam path and of the detector 50 relative to the rotating mirror in the detection beam path are described with reference to the Fig. 6 and Fig. 7 explained. Preferably, the rotating mirror 41a is arranged relative to the light source 15 such that a transmission direction of the transmitted light beam 12 emanating from the light source 15 is tangential to a mirror surface 46 of the rotating mirror in at least one rotational position of the rotating mirror 41a.

[0064] The rotating mirror in the detection beam path 44a is preferably arranged relative to the detector 50 such that a direction of the beam of reflected light 14 coming from the monitoring area is tangential to a mirror surface 47 of the rotating mirror in the detection beam path 44a in at least one rotational position of the rotating mirror in the detection beam path 44a.

[0065] Fig. Figure 6 shows a schematic representation of the light source 15 and the rotating mirror 41a. The axis of rotation of the rotating mirror 41a is perpendicular to the plane of the drawing and lies at the center of the cross-section of the rotating mirror 41a, i.e., at the intersection of the two diagonals of the square 41a. The direction of rotation of the rotating mirror 41a is indicated by an arrow θ. In the Fig. In the rotational position of the rotating mirror 41a shown in Figure 6, the direction of transmission of the transmitted light beam 12 emanating from the light source 15 is tangential to a mirror surface 46 of the rotating mirror 41a. This allows the maximum possible angular displacement of the polar angle θ to be achieved.

[0066] Fig. Figure 7 shows a schematic representation of the detector 50 and the rotating mirror 44a in the detection beam path. The axis of rotation of the rotating mirror 44a is perpendicular to the plane of the drawing and lies at the center of the cross-section of the rotating mirror 44a, i.e., at the intersection of the two diagonals of the square 44a. The direction of rotation of the rotating mirror 44a is again indicated by an arrow θ. Fig. In the rotational position of the rotating mirror 44a shown in Figure 7, the direction of the beam of reflected light 14 coming from the monitoring area 70 runs tangentially to a mirror surface 47 of the rotating mirror in the detection beam path 44a.

[0067] The present invention provides a novel optical scanner in which transmitter, receiver, optics, and evaluation modules are combined in a small, compact design to form a measuring system.

[0068] By arranging these units on a module with a motor integrated into the module, polygon mirrors are arranged on its common axis, with the receiving and transmitting sides separated by an optical separation, various versions result in an extremely compact, 3D laser scanner of the smallest design with high sensor-reliable performance.

[0069] Beam deflection can preferably be achieved using a four-sided polygon mirror to eliminate dead space scanning and achieve a high sampling rate.

[0070] According to the invention, the self-contained 2D scanner is connected to a rotation system which has contactless systems for data and energy transfer between rotor and stator.

[0071] Energy transfer preferably occurs via inductive systems and data communication via optical links, with data communication preferably being bidirectional to enable communication with the measuring system on the one hand and transmission of the spatial measurement data to the stator on the other. These systems can be implemented in a hollow axis of the rotating unit or arranged as a distributed system on circuit boards of the rotor and the stator.

[0072] The invention enables a freely rotating 360° rotation (azimuth angle) of the measuring system, thus achieving seamless 3D spatial mapping. Existing systems, such as swivel systems and laser scanners with a wired electrical connection between the stator and rotor with sensor head, fail to achieve complete and therefore seamless 360° measurement of the 3D space due to the resulting shadowing. Additionally, existing swivel systems typically only achieve a maximum scan angle of approximately 100°.

[0073] This results in a normalized maximum solid angle of only 0.5π. The monitoring area is therefore limited. In contrast, the invention achieves a nearly complete hemispherical scan of 180°×360°. This corresponds to a normalized solid angle of approximately 2π. In practice, for example, a polar angle range of 172° can be achieved.

[0074] The invention can, for example, be integrated into existing sizes and housings and achieves a size / price / performance ratio that is many times better than existing systems. Reference symbol list 10 Stator 12 transmitting lights 14 light pulses reflected from object A in the monitoring area 70 15 light transmitters 20 Rotor 21 Rotational axis of the rotor 20 22 Rotation axis of the two-dimensional scanner 40 40 two-dimensional optical scanners 41 rotating mirrors 41a Quadruple polygon mirror, rotating mirror 42 optical separation device, circuit board 44 rotating mirrors 44a Quadruple polygon mirror, rotating mirror 45 Rotary drive for mirrors 41a, 44a, circuit board motor 46 Area of ​​the polygon mirror 41a 47 Area of ​​the polygon mirror 44a 50 Detector 60 Device for contactless data and energy transmission 70 Monitoring area 80 Control and evaluation unit, control unit 81 Communication interface 82 Power supply 83 Energy transmission unit, transformer 84 Data transmission unit, data light barrier 100 optical scanners according to the invention 200 optical scanners according to the invention A Object B Latitude, line of points with constant polar angle Θ M Meridian, line of points with constant azimuthal angle φ φ Azimuthal angle Θ Polar angle x x-axis y y-axis z z-axis QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] WO 2012 / 163515 A1

[0008]

Claims

[1] Optical scanner (100; 200) based on the time-of-flight principle for detecting objects (A) in a monitored area (70) with a two-dimensional scanner (40) comprising a light emitter (15) for emitting a pulsed transmitting light beam (12) into the monitoring area (70), a detector (50) for detecting light pulses (14) reflected from an object (A) in the monitoring area (70), and a continuously rotatable rotating mirror (41; 41a) for pivoting a transmission direction of the transmitting light beam (12) over a polar angle (Θ), with a continuously rotatable rotor (20) on which at least the light emitter (15), the detector (50) and the rotating mirror (41; 41a) are arranged, for pivoting the direction of transmission of the transmitted light beam (12) over an azimuthal angle (φ), with a stator (10) relative to which the rotor (20) is rotatable about an axis of rotation (21), and with a control and evaluation unit (80) which is set up to control the light transmitter (15), to evaluate light pulses (14) detected by the detector (50) and to determine an object distance of the object (A) relative to the optical scanner (100; 200) based on the travel time of light pulses detected at a certain orientation of the transmitted light beam (12), wherein the orientation is given by the respective set polar angle (Θ) and azimuthal angle (φ), characterized by , that an optical separation device (42) is arranged between the light transmitter (15) and the detector (50) to suppress optical crosstalk from the light transmitter (15) to the detector (50), and further characterized by a device (60) for contactless transmission of data and energy between the rotor (20) and the stator (10). [2] Optical scanner according to claim 1, characterized by, that the axis of rotation (21) of the rotor (20) is perpendicular to the axis of rotation (22) of the rotating mirror (41; 41a). [3] Optical scanner according to one of claims 1 or 2, characterized by , that one direction of the transmitted light (12) arriving at the rotating mirror (41; 41a) in the transmitting beam path is perpendicular to the axis of rotation (22) of the rotating mirror (41; 41a). [4] Optical scanner according to any one of claims 1 to 3, characterized by , that the control and evaluation unit (80) is also equipped to control the rotating mirror (41; 41a) and / or the rotor (20) and / or to read out an instantaneous rotational position of the rotating mirror (41; 41a) and / or the rotor (20). [5] Optical scanner according to any one of claims 1 to 4, characterized by , that part of the control and evaluation unit (80) is formed on the rotor (20). [6] Optical scanner according to any one of claims 1 to 5, characterized bythat the optical separation device (42) has at least one partition wall that is impermeable to the transmitted light (12). [7] Optical scanner according to claim 6, characterized by , that the partition (42), the light emitter (15), the detector (50) and the rotating mirror (41; 41a) are arranged relative to each other in such a way that light (14) reflected from an object (A) in the monitoring area (70) cannot reach the detector (50) via the rotating mirror (41; 41a). [8] Optical scanner according to one of claims 6 or 7, characterized by that the partition is implemented using a circuit board. [9] Optical scanner according to any one of claims 1 to 8, characterized by , that a motor (45) integrated into the optical separation device (42) is provided to drive the rotating mirror (41; 41a). [10] Optical scanner according to claims 8 and 9, characterized by , that at least one coil of the motor (45) is formed on the circuit board (42). [11] Optical scanner according to any one of claims 1 to 10, characterized by , that the device (60) for contactless transmission of energy and data has a data light barrier. [12] Optical scanner according to any one of claims 1 to 11, characterized by , that the rotor (20) is connected to the stator (10) via a hollow shaft, wherein in particular a transmission path of one or the data light barrier runs inside the hollow shaft. [13] Optical scanner according to any one of claims 1 to 12, characterized by , that the device (60) for contactless transmission of data and energy has a transformer section between the rotor (20) and the stator (10). [14] Optical scanner according to any one of claims 1 to 13, characterized by , that the rotating mirror (41; 41a) is realized by a polygon mirror. [15] Optical scanner according to claim 14, characterized bythat the polygon mirror is a three-sided or a four-sided polygon mirror. [16] Optical scanner according to any one of claims 1 to 15, characterized by , that the rotating mirror (41; 41a) is arranged relative to the light source (15) in such a way that a direction of transmission of the emitted light beam emanating from the light source (15) is tangential to a mirror surface (46) of the rotating mirror (41; 41a) in at least one rotational position of the rotating mirror (41; 41a). [17] Optical scanner according to any one of claims 1 to 16, characterized by , that a rotating mirror (44; 44a) is present in the detection beam path upstream of the detector (50). [18] Optical scanner according to claim 17, characterized by , that the rotating mirror (44; 44a) in the detection beam path can be driven with the same drive as the rotating mirror (41; 41a) in the transmit beam path. [19] Optical scanner according to one of claims 16 or 18, characterized by, that the rotating mirror (44; 44a) in the detection beam path is arranged relative to the detector (50) such that one direction of the beam of reflected light (14) coming from the monitoring area is tangential to a mirror surface (47) of the rotating mirror (44; 44a) in the detection beam path at least in one rotational position of the rotating mirror (44; 44a). [20] Optical scanner according to any one of claims 1 to 19, further comprising a housing in which the rotor (20) and the stator (10) are housed, wherein the housing has a dome-shaped housing part made of a material transparent to the transmitted light (12). [21] Optical scanner according to claim 20, characterized by , that an opening angle of the dome-shaped housing part is at least as large as the solid angle achievable for the transmitting beam (12) when the two-dimensional scanner and the rotor interact. [22] Optical scanner according to one of claims 20 or 21, characterized by , that the dome-shaped housing part has the shape of a spherical shell with constant thickness.

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