Optical scanner

Abstract

Optical scanner based on the time-of-flight principle for detecting objects in a surveillance area (80) with a transmitter (10) for emitting light pulses (12) and a transmission beam path (14) for guiding the light pulses (12) into the monitoring area (80), wherein, for emitting the light pulses (12) in different directions into the monitoring area (80), optical components of the transmission beam path (14) are arranged on a rotor (50), and wherein at least a portion of an optical axis of the transmission beam path (14) is collinear with a rotation axis (52) of the rotor (50), and the light pulses (12) are emitted transversely to the rotation axis (52), with a receiver (30) for detecting light pulses (32) reflected by an object (82) in the monitoring area (80) and a receiving beam path (34) for guiding the reflected light pulses (32) to the receiver (30), wherein optical components of the receiving beam path (34) are arranged on the rotor (50) for receiving light pulses (32) from different directions from the monitoring area (80), and wherein at least a portion of an optical axis of the receiving beam path (34) is collinear with a rotation axis (52) of the rotor (50), with a control and evaluation unit (90) for controlling the transmitter (10) and for evaluating the light pulses (32) detected by the receiver (30) and for determining a distance (d) of the object (82) on the basis of a travel time (t) of the light pulses, characterized by that for receiving the light pulses (32), in particular from a direction of the monitoring area (80), at least two entrance lenses (36, 38) are arranged on the rotor (50) and that there is only one exit lens (22) whose optical axis (23) runs between the optical axes (35, 37) of the entrance lenses (36, 38).

Description

[0001] The present invention relates to an optical scanner based on the time-of-flight principle according to the preamble of claim 1.

[0002] A generic optical scanner based on the time-of-flight principle for detecting objects in a surveillance area has the following components: a transmitter for emitting light pulses and a transmission beam path for guiding the light pulses into the surveillance area, wherein optical components of the transmission beam path are arranged on a rotor for emitting the light pulses in different directions into the surveillance area, and wherein at least a portion of an optical axis of the transmission beam path is collinear with a rotation axis of the rotor and the light pulses are emitted transversely to the rotation axis, a receiver for detecting light pulses reflected by an object in the surveillance area and a reception beam path for guiding the reflected light pulses to the receiver,wherein optical components of the receiving beam path are arranged on the rotor for receiving light pulses from different directions from the monitoring area, and wherein at least a portion of an optical axis of the receiving beam path is collinear with a rotation axis of the rotor, and a control and evaluation unit for controlling the transmitter and for evaluating the light pulses detected by the receiver and for determining a distance of the object based on a travel time of the light pulses.

[0003] Such scanners are known in many designs and for many applications. In the generally known method of determining distance by time-of-flight measurement, a light pulse's emission time t1 and a light pulse's reception time t2 are measured, reflected by an object in the monitoring area.

[0004] The difference t2-t1 of these times, the running time, provides with the speed of light c in the respective medium (usually air) over d = c(t2-t1) / 2 the distance d of the object from the scanner.

[0005] Such optical sensors, which use a time-of-flight measurement to determine a distance, are also called TOF sensors (TOF = Time Of Flight).

[0006] Securing swing doors with a TOF-based dynamic scanner is well known. According to the data sheet, these devices have a range of several meters and incorporate an IR laser and rotating mirror. Such devices can achieve high-resolution optical monitoring even at the primary and secondary closing edges.

[0007] However, the following are considered disadvantages of these devices: the presence of moving parts with wear-prone relative movement (such as the rotating mirrors with bearings), the comparatively small scanning range, the relatively small receiving surfaces of the receivers, and the resulting use of expensive components such as APDs (Avalanche Photodiodes) and wear-prone bearings. The arrangement of the mirror, as well as the transmitter and receiver, limits the total scanning range of state-of-the-art devices to approximately 100° to 120°. In the peripheral areas, the resulting receiving surface is very small due to the geometry of the beam path on the mirror, necessitating the use of expensive components in the receiver.

[0008] A fundamental objective of these scanners is to increase the signal-to-noise ratio. While significant improvements can be achieved by using lasers as light transmitters, limitations arise due to eye safety requirements.

[0009] WO2018 / 054512A1 discloses a LIDAR sensor with a rotor and a stator, wherein a transmitting optics and a receiving optics are arranged on the rotor and a radiation source and a light receiver are arranged on the stator on the rotation axis.

[0010] DE102016010102A1 describes an optical sensor with a rotor and a stator, wherein a receiver is arranged on the stator on the rotation axis and at least one laser is present on the rotor as a radiation source.

[0011] It can be considered that an object of the invention is to provide a scanner of the above-mentioned type with increased sensitivity.

[0012] This object is achieved by the optical scanner having the features of claim 1.

[0013] Preferred embodiments of the optical scanner according to the invention are explained below, in particular in connection with the dependent claims and the figures.

[0014] The optical scanner of the type specified above is further developed according to the invention in that at least two entrance lenses are arranged on the rotor for receiving the light pulses from a direction of the monitoring area.

[0015] In principle, the objects to be detected can be of any type, as long as they re-radiate the incoming light pulses toward the scanner with sufficient intensity, i.e., they backscatter or reflect them. For applications involving doors and gates, the objects to be detected can also include people.

[0016] The term "surveillance zone" refers to the spatial area in which objects can generally be detected. This zone is limited by the intensity of the emitted light pulses on the one hand and the reflected light pulses on the other.

[0017] In principle, any radiation source capable of generating the required light pulses with the desired intensity, spectral composition, and temporal structuring can be used as a transmitter. Light-emitting diodes or laser diodes, such as VCSELs, are particularly preferred, especially in the visible or infrared spectral range.

[0018] In principle, known components can be used as receivers that can detect the reflected light pulses with sufficient sensitivity. Photodiodes are preferred. If necessary, color filters can be installed upstream to suppress stray light.

[0019] The transmit beam path for guiding the light pulses into the monitored area and the receive beam path for guiding the reflected light pulses to the receiver can be formed by beam-guiding components, such as lenses, prisms and mirrors.

[0020] The term “different directions” essentially refers to different azimuthal directions with respect to the rotation axis.

[0021] The emission of the light pulses transverse to the rotation axis includes in particular the emission of the light pulses perpendicular to the rotation axis.

[0022] For the mechanics of the rotor, basically known components such as ball bearings, needle bearings, roller bearings, and magnetic drives can be used.

[0023] Microcontrollers or comparable intelligent and programmable components can be used as control and evaluation units, in particular programmable ones.

[0024] The invention provides a particularly powerful optical scanner with a potentially large scanning range, which is also cost-effective to manufacture compared to the prior art. A particular advantage of the optical scanner according to the invention is that, in principle, inexpensive photodiodes can also be used as receivers and LEDs as light sources. The disadvantages of the prior art described above are thus significantly reduced.

[0025] The optical sensor according to the invention can be advantageously used for securing and monitoring the closing edges, in particular main closing edges and secondary closing edges, of swing doors in order to avoid or prevent impact on the door leaf and pinching or crushing of body parts, in particular fingers, when opening or closing the door.

[0026] Furthermore, the optical sensor according to the invention can be advantageously used for securing objects, for example house walls, as well as for the navigation of vehicles.

[0027] With the optical sensor according to the invention, scanning ranges of up to 270° can be easily achieved. This also allows the sensor's application areas to be expanded. In particular, the optical scanner according to the invention can also be used in a security sensor, and navigation applications are also possible.

[0028] 2 In principle, there is no need for a separate transmitting or exit lens, particularly if a laser diode is used as the light source. In order to emit emitted light pulses with a smaller divergence into the monitored area, it may be expedient, however, to arrange one or more exit lenses on the rotor to emit the light pulses into the monitored area. The exit lenses can be arranged one above the other in the direction of the rotation axis or laterally next to each other, in particular directly adjacent to each other. The optical axes of the exit lenses can run parallel to each other. The optical axis of one exit lens or of all exit lenses can intersect the rotation axis or be skew to the rotation axis.In a preferred variant, two exit lenses with mutually parallel optical axes are present, wherein the direction of the rotation axis can correspond to the normal direction of the surface formed by the optical axes.

[0029] Two lines are skew if they do not intersect and are not parallel. Skew lines are also called crossing lines.

[0030] The entrance lenses can also be arranged on the rotor one above the other in the direction of the rotation axis or laterally next to each other, in particular directly adjacent to each other. The optical axes of the entrance lenses can run parallel to each other. The optical axis of one entrance lens or of all entrance lenses can intersect the rotation axis or be skewed to the rotation axis. In a preferred variant, two entrance lenses with mutually parallel optical axes are present, wherein the direction of the rotation axis can correspond to the normal direction of the surface formed by the optical axes.

[0031] In principle, there is considerable freedom regarding the exact location of the components on or at the rotor. Relatively flat designs of the scanner according to the invention can be achieved if the entrance lenses and at least one exit lens are arranged on the same side of the rotor relative to a direction defined by the rotation axis.

[0032] According to the invention, only one exit lens is present, whose optical axis runs between the optical axes of the entrance lenses. This results in a space-saving arrangement.

[0033] Particularly preferred embodiments of the scanner according to the invention are characterized in that the transmitter is arranged stationary relative to a housing of the scanner, such that the light pulses are emitted in the direction of the rotation axis and in the direction of the rotor.

[0034] In this context, it is also advantageous if the receiver is arranged stationary relative to the housing of the scanner, such that the light pulses are received from the direction of the rotation axis and the direction of the rotor.

[0035] Due to the stationary arrangement of transmitter and receiver, they can be connected to the control and evaluation unit easily and reliably.

[0036] To guide the reflected light pulses towards the receiver, a mirror can advantageously be mounted on the rotor on the rotation axis.

[0037] Furthermore, at least one mirror can advantageously be mounted on the rotor on the rotation axis to deflect the light pulses emitted by the transmitter in the direction of the transmission beam path.

[0038] To minimize the adjustment effort for the optical components, beam paths with longer focal lengths are preferred over shorter ones. For this purpose, it can be advantageous to fold the beam paths, i.e., to guide the light pulses via mirrors.

[0039] A particularly preferred embodiment in this context is characterized in that the entrance lenses are arranged on a periphery of the rotor and that at least one mirror is present on the rotor radially opposite the entrance lenses, with which the reflected light pulses are guided in the direction of the receiver.

[0040] This basic idea is used in a further embodiment for the transmission beam path, in which the exit lenses are arranged on a periphery of the rotor and at least one mirror is present on the rotor radially opposite the exit lenses, with which the light pulses coming from the transmitter are guided in the direction of the exit lenses.

[0041] All mirrors described here can be flat mirrors or concave mirrors, for example parabolic mirrors.

[0042] Particularly long focal lengths in the receiving beam path are possible in a particularly preferred embodiment in which the reflected light pulses are guided downstream of the entrance lenses via at least one further mirror and the mirror on the rotation axis of the rotor to the receiver.

[0043] Particularly long focal lengths in the transmission beam path can be achieved if the light pulses emitted by the transmitter are guided to the exit lens or exit lenses via the mirror on the rotation axis and at least one other mirror on the rotor.

[0044] Further features and advantages of the present invention are explained below with reference to the accompanying figures, in which: Fig. 1: an example of a scanner in a longitudinal section; Fig. 2: a cross-sectional view of the scanner from Fig. 1; Fig. 3: in a longitudinal sectional view, an embodiment of a scanner according to the invention; Fig. 4: in a longitudinal sectional view, an embodiment of a scanner according to the invention; and Fig. 5: a cross-sectional view of the scanner from Fig. 4.

[0045] Identical and equivalent components are generally identified with the same reference numerals in all figures.

[0046] A first example of a scanner 100 is described with reference to the Fig. 1 and Fig. 2 explained. Fig. 1 shows a longitudinal sectional view along a rotation axis 52 and Fig. 2 a cross-sectional view perpendicular to the rotation axis 52 of the scanner 100.

[0047] The optical scanner 100 represents a sandwich system with a Fig. 1 transmitter system located above and a receiver system located below. Between them is a bearing and drive unit for a rotor 50. The transmitter and receiver sides are separated to prevent optical crosstalk. On each side of the rotor 50, two lenses, namely exit lenses 16, 18 and entrance lenses 36, 38, are mounted side by side to avoid the space for the central rotation axis 52.

[0048] The optical scanner 100 comprises the following essential components: a transmitter 10 for emitting light pulses 12 into the monitoring area 80, a receiver 30 for detecting light pulses 32 reflected by an object 82 in the monitoring area 80, and a control and evaluation unit 90 for controlling the transmitter 10 and evaluating the light pulses 32 detected by the receiver 30 and for determining a distance d of the object 82 from the scanner 100 based on a travel time t of the light pulses. The transmitter 10 can, in particular, be a light-emitting diode.

[0049] A transmit beam path 14 is provided for guiding the light pulses 12 into the monitored area 80. A receive beam path 34 is provided for guiding the reflected light pulses 32 to the receiver 30. Optical components of the transmit beam path 14 are arranged on a rotor 50 to emit the light pulses 12 in different directions into the monitored area 80. Correspondingly, optical components of the receive beam path 34 are arranged on the rotor 50 to receive reflected light pulses 32 from different directions from the monitored area 80.

[0050] At least a portion of an optical axis of the transmit beam path 14 is collinear with the rotation axis 52 of the rotor 50. The light pulses 12 are emitted into the monitoring area 80 transversely to the rotation axis 52, namely perpendicular to the rotation axis 52 in the illustrated embodiment. According to the invention, a portion of an optical axis of the receive beam path 34 is also collinear with a rotation axis 52 of the rotor 50.

[0051] Finally, to receive the light pulses 32 from a direction of the monitoring area 80, two entrance lenses 36, 38 are arranged on the rotor 50, wherein the entrance lens 38 is in the Fig. 1 and Fig. 2 is not visible. The entrance lens 38 is located in Fig. 1 just behind the entrance lens 36.

[0052] In the Fig. 1 and Fig. In the scanner 100 shown in Figure 2, two exit lenses 16, 18 are arranged laterally adjacent to each other on the rotor 50 for emitting the light pulses 12 in a direction of the monitoring area 80. The optical axes of the exit lenses 16, 18 are parallel to each other and each skewed to the rotation axis 52, which is perpendicular to the plane formed by the optical axes of the exit lenses 16, 18. The exit lens 18 is located in Fig. 1 behind the exit lens 16.

[0053] The entrance lenses 36, 38 are also arranged laterally adjacent to one another on the rotor 50. The optical axes of the entrance lenses 36, 38 are also parallel to one another and each skews to the rotation axis 52. The optical axes of the entrance lenses 36, 38 also run parallel to the optical axes of the exit lenses 16, 18.

[0054] As from Fig. 1, the exit lenses 16, 18 on the one hand and the entrance lenses 36, 38 on the other hand are arranged on opposite sides of the rotor 50 with respect to the direction given by the rotation axis 52.

[0055] The components of the scanner 100 according to the invention are accommodated in a housing 60 with a front panel 62 that is transparent to the light pulses 12 and the reflected light pulses 32.

[0056] The transmitter 10, for example a light-emitting diode or a laser diode, is arranged stationary relative to the housing 60, such that the light pulses 12 are directed in the direction of the rotation axis 52, in Fig. 1 downwards and in the direction of the rotor 50. To deflect the light pulses 12 emitted by the transmitter 10 in the direction of the transmission beam path 14, a mirror 24 is mounted on the rotor 50 on the rotation axis 52.

[0057] The receiver 30 is also arranged stationary relative to the housing 60, such that the light pulses 32 are received from the direction of the rotation axis 52 and the direction of the rotor 50. To guide the reflected light pulses 32 toward the receiver 30, a mirror 44 is mounted on the rotor 50 on the rotation axis 52.

[0058] The entrance lenses 36, 38 are, as can be seen Fig. 1, arranged on a periphery of the rotor 50 and radially opposite the entrance lenses 36, 38, there are mirrors 39, 41 on the rotor 50, with which the reflected light pulses 32 are guided in the direction of the receiver 30. The mirror 41 is in the Fig. 1 and Fig. 2 not shown, it is located in Fig. 1 relative to the paper plane behind the mirror 39.

[0059] As continues from Fig. 1, the exit lenses 16, 18 are also arranged on a periphery of the rotor 50 and radially opposite the exit lenses 16, 18 there are mirrors 19, 21 on the rotor 50, with which the light pulses 12 coming from the transmitter 10 are guided in the direction of the exit lenses 16, 18.

[0060] In the embodiment of the Fig. 1 and Fig. 2, the reflected light pulses 32 are guided downstream from the entrance lenses 36, 38 via the mirrors 39, 41 and the mirror 44 on the rotation axis 52 of the rotor 50 to the receiver 30. In addition, the light pulses 12 emitted by the transmitter 10 are guided via the mirror 24 on the rotation axis 52 and the mirrors 19, 21 on the rotor 50 to the exit lenses 16, 18. In the embodiment of the Fig. 1 and Fig. 2, the receiving beam path 34 comprises the entrance lenses 36, 38 and the mirrors 39, 41, 44 as components. Accordingly, the transmitting beam path 14 comprises the exit lenses 16, 18 and the mirrors 19, 21, 24 as components. Because the light pulses 12, 32 are each deflected by 90°, the mirrors 4, 20, and 44 can also be referred to as 45-degree mirrors.

[0061] The rotor 50 is mounted relative to the stationary parts of the housing 60 by suitable and schematically illustrated bearings 54, 55, for example, ball, needle, or roller bearings. Advantageously, at least two bearings are used to ensure smooth running of the rotor 50. Commercially available components can be used for the bearings, for which other arrangements are also possible.

[0062] The optical scanner 100 operates as follows: The transmitter 10 emits light pulses 12, which are radiated into the monitoring area 80 via the mirrors 19, 21, and 24 and the exit lenses 16, 18. Light pulses are reflected back by an object 82 located in the monitoring area 80. The reflected light pulses 32 enter via the entrance lenses 36, 38 and are guided via the mirrors 39, 41, and 44 to the receiver 30, where they are detected. The scanner 100 measures, in a generally known manner, the time t1 at which a light pulse 12 is emitted and the time t2 at which the corresponding reflected light pulse 32 is detected by the receiver 30. According to d = c(t2-t1) / 2 From these times t1, t2 and the speed of light c, a distance of the object 82 from the scanner 100 is determined.

[0063] The rotor 50 rotates in a direction indicated by the arrow 53. This allows the light pulses 12 to be emitted in different directions, namely different azimuthal directions, into the monitoring area 80, and light pulses 32 reflected from different azimuthal directions from the monitoring area 80 can also be detected. Using a sensor (not shown in the figures) that records the angular position of the rotor 50, an angular coordinate φ for a detected object 82 can be recorded in addition to the distance coordinate d. A zero point for the angular coordinate φ can, for example, be set such that in the Fig. The horizontal line φ = 0 corresponds to the situation shown in Figure 2.

[0064] An essential technical feature of this embodiment of the optical scanner according to the invention is that, on the one hand, the mirror and lens system rotates during measuring operation, and, on the other hand, the transmitter 10 and the receiver 30 remain stationary. The resulting transmitting and receiving area is therefore always the same size for all angular positions of the rotor.

[0065] For the Fig. 3 schematically illustrated embodiment only the differences compared to the embodiment of the Fig. 1 and Fig. 2 explained.

[0066] The main difference of the Fig. 3 schematically illustrated embodiment of a scanner 200 according to the invention in comparison to the embodiment of Fig. 1 and Fig. 2 is that a more intense light source, for example a laser diode, is used as the transmitter 10. This measure can significantly increase the range of the optical scanner 200. Due to the comparatively low beam divergence of the laser diode, a single exit lens 22 is sufficient to guide the light pulses 12, which, in addition, is Fig. 1 and Fig. 2 is smaller. The beam guidance for the light pulses 12 is at Fig. 3 compared to the Fig. 1 and Fig. 2 is simpler in that the transmission pulses from the transmitter 10 are transmitted directly via the mirror 24, not as in the Fig. 1 and Fig. 2, via the further mirrors 19, 21, directly to the exit lens 22.

[0067] The optical axis 23 of the exit lens 22 runs parallel to the optical axes 35, 37 of the entrance lenses 36, 38. In the projection along the rotation axis 52, the optical axis 23 of the exit lens 22 runs between the optical axes 36, 38 of the entrance lenses 36, 38 and intersects the rotation axis 52.

[0068] Because of the slightly smaller exit lenses 22, the structure is Fig. 3 slightly flatter than that of the embodiment of the Fig. 1 and Fig. 2.

[0069] When using laser diodes, Class 1 eye safety requirements must be observed. To reduce the IR pulse power from 75W to an average of 0.25mW, a duty cycle of 1:300,000 is necessary. By rotating the laser and dividing the scan area into approximately 8 segments of 45° each, the duty cycle can be changed to 1:40,000 for a shorter response time or more measurement points, which corresponds to a finer resolution. With a pulse duration of 5ns, a measurement is possible every 200µs. At a rotation speed of 1500rpm (25Hz), a time of 40ms is available for one rotation. This allows 200 measurements per rotation, resulting in a resolution of just under 2° for individual shots without averaging.

[0070] The Fig. 4 and Fig. The embodiment of an optical scanner 300 shown in Figure 5 has similarities to the variant of Fig. 3 to the effect that here too a comparison with, for example, the Fig. 1 and Fig. 2 more intense light source, for example a laser diode, is used and thus also here a single, in comparison to, for example, the Fig. 1 and Fig. 2 smaller exit lens 22 is used. The main difference compared to the embodiment from Fig. 3 is that the exit lens 22 is arranged on the same side of the rotor 50 as the entrance lenses 36, 38 with respect to a direction given by the rotation axis 52. In comparison to the embodiments of Fig. 1 to 3, an even flatter design of the housing 60 can be achieved.

[0071] The overall height of the optical scanner 300 can be significantly reduced because the exit lens 22 is arranged between the two entrance lenses 36, 38. The 45° mirror 25 can advantageously be mirrored on both sides and designed with the tube so that no optical crosstalk occurs. However, the optical scanner 300 requires larger-diameter bearings for mounting on a hollow axle. An even smaller overall height is possible if only one bearing, for example, a roller or needle bearing, is arranged between the transmitter and receiver sides of the rotor 50.

[0072] When using infrared LEDs as light sources, eye safety requirements are easily met. However, the lower pulse power must be compensated for by numerous measurements and averaging. With the sample measurement core, a new measurement can be taken approximately every 4 µs, corresponding to a duty cycle of the LED of 1:1000. With 128 measurements, each measurement point requires 0.5 ms. Thus, in 40 ms, which corresponds to one rotation of the rotor, 50 or 80 measurement points could be scanned, evenly spaced over 360° at intervals of 4.5° each.

[0073] With a measurement range of, for example, 180°, only 40 measurement points could be scanned in 40 ms for one rotation. If the averaging were distributed over two rotations, 80 measurement points could be scanned at intervals of 2.25° each. However, the scanning time would then be 2 x 40 ms = 80 ms. Fast-moving objects can then only be detected more slowly, and the objects (e.g., a person's arm) would have to remain in the monitoring area or detection field longer for detection.

[0074] Reducing the measuring range from 180° to 100° to 120°, which corresponds to 44 to 53 beams for monitoring a door leaf, for example, would not reduce the sampling time of 80ms, since the rotational speed remains constant.

[0075] If necessary, the rotor 50 must be individually balanced with plastic parts.

[0076] If smaller scanning angles are required, the transmitting and receiving elements can also be arranged close to the optical axis, allowing through-hole axes to be used and the bearings to be placed externally. This is not shown in the figures. The shadowing of the optoelectronic components by the axes then limits the scanning angle. However, an arrangement with multiple segments is also possible.

[0077] The present invention provides a novel optical scanner with a potentially large scanning range. A particular advantage of the optical scanner according to the invention is that, in simple configurations, inexpensive photodiodes and also inexpensive light-emitting diodes can be used instead of pulsed laser diodes. This makes the scanner according to the invention more powerful and less expensive than prior art solutions. List of reference symbols 10 channels 12 light pulses 14 Transmission beam path 15 optical axis of exit lens 16 16 Exit lens 17 optical axis of exit lens 18 18 Exit lens 19 mirrors 21 mirrors 22 single exit lens 23 optical axis of single exit lens 22 24 mirrors on rotation axis 52 25 mirrors on rotation axis 52 30 recipients 32 reflected light pulses 34 Receiving beam path 35 optical axis of entrance lens 36 36 entrance lens 37 optical axis of entrance lens 38 38 entrance lens 39 mirrors 41 mirrors 44 mirrors on rotation axis 52 50 rotor 52 Rotation axis of rotor 50 53 Arrow: Direction of rotation 54 warehouses 55 warehouses 60 housings 62 cutting disc 80 surveillance area 82 Object in the surveillance area 80 90 Control and evaluation unit 100 scanners 200 scanners 300 scanners d distance t duration φ angular coordinate

Claims

[1] Optical scanner based on the time-of-flight principle for detecting objects in a surveillance area (80) with a transmitter (10) for emitting light pulses (12) and a transmission beam path (14) for guiding the light pulses (12) into the monitoring area (80), wherein, for emitting the light pulses (12) in different directions into the monitoring area (80), optical components of the transmission beam path (14) are arranged on a rotor (50), and wherein at least a portion of an optical axis of the transmission beam path (14) is collinear with a rotation axis (52) of the rotor (50), and the light pulses (12) are emitted transversely to the rotation axis (52), with a receiver (30) for detecting light pulses (32) reflected by an object (82) in the monitoring area (80) and a receiving beam path (34) for guiding the reflected light pulses (32) to the receiver (30), wherein optical components of the receiving beam path (34) are arranged on the rotor (50) for receiving light pulses (32) from different directions from the monitoring area (80), and wherein at least a portion of an optical axis of the receiving beam path (34) is collinear with a rotation axis (52) of the rotor (50), with a control and evaluation unit (90) for controlling the transmitter (10) and for evaluating the light pulses (32) detected by the receiver (30) and for determining a distance (d) of the object (82) on the basis of a travel time (t) of the light pulses, characterized by , that for receiving the light pulses (32), in particular from a direction of the monitoring area (80), at least two entrance lenses (36, 38) are arranged on the rotor (50) and that there is only one exit lens (22) whose optical axis (23) runs between the optical axes (35, 37) of the entrance lenses (36, 38). [2] Scanner according to claim 1, characterized by that a plurality of exit lenses (16, 18) are arranged on the rotor (50) for emitting the light pulses (12) in a direction of the monitoring area (80). [3] Scanner according to claim 1 or 2, characterized by that the entrance lenses (36, 38) are arranged laterally, in particular immediately adjacent, next to one another on the rotor (50). [4] Scanner according to one of claims 1 or 2, characterized by that the entrance lenses on the rotor are arranged one above the other in the direction of the axis of rotation, in particular directly adjacent to one another. [5] Scanner according to one of claims 1 to 4, characterized by that the entrance lenses (36, 38) and an exit lens (16, 18) are arranged on the same side of the rotor (50) with respect to a direction given by the axis of rotation (52). [6] Scanner according to one of claims 1 to 5, characterized bythat the transmitter (10) is arranged at rest relative to a housing (60) of the scanner (100) in such a way that the light pulses (12) are emitted in the direction of the rotation axis (52) and in the direction of the rotor (50). [7] Scanner according to one of claims 1 to 6, characterized by that the receiver (30) is arranged stationary relative to the housing (60) of the scanner (100) such that the light pulses (32) are received from the direction of the rotation axis (52) and the direction of the rotor (50). [8] Scanner according to one of claims 1 to 7, characterized by that the entrance lenses (36, 38) are arranged on a periphery of the rotor (50) and that at least one mirror (39, 41) is present on the rotor (50) radially opposite the entrance lenses (36, 38), with which mirror or mirrors the reflected light pulses (32) are guided in the direction of the receiver (30). [9] Scanner according to one of claims 1 to 8, characterized bythat the exit lenses (16, 18) are arranged on a periphery of the rotor (50) and that at least one mirror (19, 21) is present on the rotor (50) radially opposite the exit lenses (16, 18), with which mirror or mirrors the light pulses (12) coming from the transmitter (10) are guided in the direction of the exit lenses (16, 18). [10] Scanner according to one of claims 1 to 9, characterized by that a mirror (44) is mounted on the rotor (50) on the rotation axis (52) for guiding the reflected light pulses (32) in the direction of the receiver (30). [11] Scanner according to one of claims 1 to 10, characterized by that at least one mirror (24) is mounted on the rotor (50) on the rotation axis (52) for deflecting the light pulses (12) emitted by the transmitter (10) in the direction of the transmission beam path (14). [12] Scanner according to claims 8 and 10, characterized bythat the reflected light pulses (32) are guided downstream of the entrance lenses (36, 38) via at least one further mirror (39, 41) and the mirror (44) on the rotation axis (52) of the rotor (50) to the receiver (30). [13] Scanner according to claims 9 and 11, characterized by that the light pulses (12) emitted by the transmitter (10) are guided to the exit lens (22) via the mirror (24) on the rotation axis (52) and at least one further mirror (19, 21) on the rotor (50).

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