Laser scanner

Abstract

The present invention relates to a laser scanner (1), comprising a housing (23), a laser emitter (11) including an emission aperture (S) for emitting a light beam (12), a laser receiver (16) for receiving the light beam (15), and a beam deflection device in the form of a mirror cone (2), the cone axis of the mirror cone forming its axis of rotation (2'), each of the individual cone sides of the mirror cone forming a mirror surface (7 - 10), wherein the laser emitter (11) and the laser receiver (16) each point towards the mirror cone parallel to the axis of rotation (2') of the mirror cone (2), the laser receiver (16) comprising at least one converging lens (20) arranged downstream of the mirror cone (2) in the received light beam path, and in the region of the converging lens (20) overlapping with the mirror surfaces (7 - 10), the converging lens, viewed in the direction of the axis of rotation (2'), is at least twice as large in area comparison as the largest mirror surface among all the mirror surfaces (7 - 10) viewed in the direction of the axis of rotation (2').

Description

Field of the Invention

[0001] The present invention relates to a laser scanner, comprising a housing, a laser emitter, a laser receiver and a beam deflection device. The laser emitter comprises an emission aperture for emitting an emission beam. The laser receiver comprises a reception aperture for receiving the emission beam reflected by the environment as a reception beam. The beam deflection device is located in the beam path of the emission beam and the reception beam in the form of a mirror cone mounted on a rotatable shaft. Wherein the cone axis of the mirror cone forms the rotation axis, and each of the cone sides of the mirror cone inclined to the rotation axis forms a mirror surface, and wherein the laser emitter and the laser receiver each point to the mirror cone substantially parallel to the rotation axis of the mirror cone. Background Art

[0002] For example, such a laser scanner is known from EP2622364A1 or EP3182159A1. The emission beam pointing axially parallel to the rotating mirror cone is periodically pivoted by the mirror cone within the scanning angle range, and the received beam reflected by the environment is received back in the same way, i.e., the mirror surface currently used for emission is simultaneously used to deflect the received beam received from the same direction to the laser receiver.

[0003] According to the prior art (e.g., EP2293013A1), the circular reception aperture of the laser receiver is smaller than the inscribed circle of the "active" mirror surface viewed along the direction of the rotation axis. The corresponding active mirror surface of the laser scanner is such a mirror surface through which the emission beam is deflected in its scanning direction, because the reflected received beam is also received from this direction and is returned to the receiver by the active mirror surface. When the mirror surface rotates, the reception aperture circle crosses the edge between two mirror surfaces, with the result that the reception aperture circle is continuously cut, or the portion of the reception circle aperture located on the active mirror surface is continuously reduced, which leads to a periodic, angle-dependent sensitivity drop of the laser scanner.

[0004] CN 207020306U shows a laser scanner, which includes a housing, a laser transmitter including an emission aperture for emitting an emission beam, a laser receiver for receiving the emission beam reflected by the environment as a reception beam, and a beam deflection device. The beam deflection device is located in the beam paths of the emission and reception beams in the form of a mirror cone mounted on a rotatable shaft. Wherein the cone axis of the mirror cone forms the rotation axis, and each of the respective cone sides of the mirror cone inclined to the rotation axis forms a mirror surface. The laser transmitter and the laser receiver each point to the mirror cone substantially parallel to the rotation axis of the mirror cone, and the laser receiver has at least one converging lens, which is arranged downstream of the mirror cone in the reception beam path. Even if it is determined in this document that the converging lens of the reception aperture is slightly larger than the mirror surface, the same cutting effect as that of the laser scanner of EP2293013A1 occurs during the rotation of the mirror cone, and thus the same periodic sensitivity drop occurs. Summary of the Invention

[0005] The object of the present invention is to create a laser scanner with improved reception sensitivity and thus a wider range.

[0006] This object is achieved by a laser scanner, which includes a housing, a laser transmitter including an emission aperture for emitting an emission beam, a laser receiver for receiving the emission beam reflected by the environment as a reception beam, and a beam deflection device located in the beam paths of the emission beam and the reception beam in the form of a mirror cone mounted on a rotatable shaft. Wherein the cone axis of the mirror cone forms the rotation axis, wherein each of the respective cone sides of the mirror cone inclined to the rotation axis forms a mirror surface, wherein the laser transmitter and the laser receiver each point to the mirror cone substantially parallel to the rotation axis of the mirror cone, wherein the laser receiver has at least one converging lens, the at least one converging lens is arranged downstream of the mirror cone in the reception beam path, and wherein in the region of the converging lens overlapping with the mirror surface, the converging lens observed in the direction of the rotation axis is at least twice as large in area comparison as the largest mirror surface among all the mirror surfaces observed in the direction of the rotation axis.

[0007] Different from the known solutions, it is no longer the reception aperture that "adapts" to the mirror surface, but on the contrary, the mirror surface adapts to the reception aperture. According to the present invention, since the reception aperture is larger than the mirror surface, it is first used entirely around the central position of the emission beam on at least the effective mirror surface.

[0008] When the mirror cone is configured with a plurality of cone sides having different inclinations, in particular for emitting the emission beam in a plurality of scanning sectors separated from each other, the mirror surface can have different sizes when viewed in the direction of the axis of rotation. For this purpose, the receiving aperture viewed in the direction of the axis of rotation is larger than the largest mirror surface among all the mirror surfaces viewed in the direction of the axis of rotation, so as to achieve the above effect in all scanning sectors.

[0009] According to the invention, in the region of the converging lens that overlaps with the mirror surface, the converging lens viewed in the direction of the axis of rotation is at least twice as large in area comparison as the largest mirror surface among all the mirror surfaces viewed in the direction of the axis of rotation. As a result, this achieves that, even when the emission beam has a small diameter, the mirror surface is located within the receiving aperture when viewed in the direction of the axis of rotation over its entire movement path on which it is struck by the emission beam, that is, its emission aperture is smaller compared to the corresponding active mirror surface. In this way, the entire active mirror surface is used to receive the received beam during the entire deflection movement of the emission beam, and thus, the reception sensitivity of the laser scanner is optimized.

[0010] According to a preferred feature of the invention, on the other hand, the receiving aperture is not designed to be too large so that it unnecessarily receives light components from non-active mirror surfaces. Therefore, in the region where the converging lens overlaps with the mirror surface, when viewed in the direction of the axis of rotation, the converging lens is preferably approximately twice as large in area comparison as the largest mirror surface among all the mirror surfaces viewed in the direction of the axis of rotation. This optimizes the reception sensitivity and maximally suppresses parasitic reflections.

[0011] This is particularly advantageous when the converging lens is formed by a converging lens that is approximately circular when viewed in the direction of the axis of rotation and whose optical axis lies on the axis of rotation, and a diaphragm provided upstream of the converging lens. This results in a very simple symmetric design, in which, when viewed in the direction of the axis of rotation, the converging lens with a large diameter is located substantially equally on the mirror cone, while the diaphragm is used to mask the parasitic reflections of the non-active mirror surfaces. When the mirror cone has four mirror surfaces, for example, when viewed in the direction of the axis of rotation, the diaphragm preferably has a semi-circular shape so as to mask two non-active mirror surfaces.

[0012] As an alternative, instead of using a diaphragm for a circular converging lens, a converging lens that is approximately fan-shaped when viewed in the direction of the axis of rotation and whose optical axis lies on the axis of rotation can also be used, in particular a semi-circular converging lens for a mirror cone including four mirror surfaces.

[0013] The laser receiver preferably includes a receiving element which is arranged, particularly preferably in the form of a photomultiplier or an avalanche photodiode, at the focal point of a converging lens. This design ensures high receiving sensitivity while providing a large aperture of the laser receiver.

[0014] The laser transmitter can be located directly in the receiving beam path between the mirror cone and the laser receiver, for example when it is a very small semiconductor laser that only slightly covers the receiving aperture. However, preferably, the laser transmitter includes a deflecting mirror located in the receiving beam path between the mirror cone and the laser receiver, and a laser pointing at the deflecting mirror and located outside the receiving beam path, so as to shield the receiving aperture as little as possible.

[0015] According to another preferred feature of the present invention, the laser transmitter points at the edge region of the bottom side of the mirror cone. In this way, the available movement path of the active mirror surface is increased, that is, its rotation angle around the rotation axis of the mirror cone. Due to the limited, non-point-like emission aperture of the laser transmitter, the emission beam can only be used within the angular range of the rotational movement on which the emission beam of the active mirror surface is fully or substantially fully located, because otherwise adjacent mirror surfaces will also be hit, and the emission beam will thus be deflected in different, unwanted directions. By moving the emission beam to the edge region of the active mirror surface, its available rotation angle range is maximized to emit the emission beam.

[0016] Therefore, the diameter of the emission aperture of the laser transmitter at the level of a mirror surface is preferably less than one quarter, and particularly preferably less than one eighth, of the circumferential range of the mirror surface in the above-mentioned edge region.

[0017] Another advantage of the edge-side illumination of the mirror cone by the laser transmitter relates to the exit window of the housing through which the emission and receiving beams pass. In particular, when the housing includes a window that points at the circumference of the mirror cone and is made of a transparent material for the emission and receiving beams to pass through, the window is divided into at least three parts that are angled relative to each other when viewed in the circumferential direction of the mirror cone, and the length of the central part is preferably at least such that the emission beam deflected by the mirror cone only passes through the central part. In this way, it is possible to prevent the emission beam from being refracted in an uncontrolled or unwanted manner by the curvature of the glass window. Combining the above-mentioned advantageous edge-side illumination of the mirror cone by the laser transmitter, which makes the illumination point of the emission beam on the active mirror surface closer to the glass window located tangentially thereto, the central part can be kept particularly short, which allows for a particularly compact design of the laser scanner.

[0018] In each of these embodiments, the mirror cone can be regular so as to emit the emission beam in the form of a single scanning fan, or, as discussed, at least two cone sides of the mirror cone can have different inclinations so as to emit the emission beam in at least two different scanning fans. Description of the Drawings

[0019] The present invention will be described in more detail below based on exemplary embodiments shown in the drawings. In the drawings:

[0020] Figure 1 A laser scanner without a housing according to the present invention is shown in a schematic perspective view;

[0021] Figure 2 Is shown in block diagram Figure 1 Of the laser scanner, in which the beam path is schematically shown; and

[0022] Figures 3a to 3c A top view of the mirror cone projected in the direction of the axis of rotation of the mirror cone shows the mirror cone and Figure 1 And Figure 2 The housing window of the laser scanner in three different rotational positions of the mirror cone relative to the emission and reception apertures of the laser emitter and the laser receiver in each case. Detailed Description of the Invention

[0023] Figure 1 The laser scanner 1 is schematically shown, which includes a mirror cone 2 mounted on a shaft 3 and rotated by a motor 4. A rotary angle encoder or sensor 5 is flange-mounted to the motor 4 and measures or encodes the current position of the mirror cone 2 and sends its signal to the electronic unit 6( Figure 2 ).

[0024] The mirror cone 2 has the shape of a four-sided cone, and its cone axis 2' is its axis of rotation. The cone sides 7 - 10 inclined relative to the axis of rotation 2' form the mirror surfaces of the mirror cone 2.

[0025] It should be understood that in this specification, the terms "cone shape" or "mirror cone" respectively denote any type of cone having an arbitrary polygonal base, including a right cone as well as an "oblique" cone (the cone axis is not perpendicular to the base), regular and irregular cones, solid or "truncated" cones ("truncated cones of the cone"), and cones cut at their tips and / or bases, such as Figure 1 And 2 The cones shown in, the bases of which are cut in a circular manner to reduce air resistance during rotation.

[0026] The laser emitter 11 points at the mirror cone 2, which, during its rotation, emits the emission beam 12 at the mirror surfaces 7 - 10, in particular at a respective one ("active") mirror surface 7 - 10, such that the emission beam 12 is periodically pivoted through the scanning angle α by the rotational movement of the mirror cone 2 to form the scanning fan 13. When the scanning fan 13, for example the entire laser scanner 1, moves across the surface 14 in a direction R, for example perpendicular to the scanning fan 13, outside the scanning plane, the scanning fan 13 can be used, for example, to scan the surface 14 "row by row".

[0027] The reflection of the emission beam 12 or the scanning fan 13 by the surface 14 is detected by the laser receiver 16, which in turn receives these reflections as the received beam 15 via the mirror cone 2, converts these reflections into electrical signals and feeds the electrical signals to the electronic unit 6 for analysis. For this purpose, the latter activates the laser emitter 11, for example, in a triggering, pulsed, modulated or the like manner as is known in the art.

[0028] The mirror cone 2 observed here is of a specific type, more specifically, at least one of the cone sides 7 - 10 has a different inclination with respect to the axis of rotation 2' compared to the remaining cone sides 7 - 10. Thus, during the rotation of the mirror cone 2, not only is a single scanning fan 13 obtained, but depending on the number of inclinations, two, three or more separate scanning fans 13, 17, etc. are obtained. This type of laser scanner is required for various application purposes, for example for detecting undercuts of the surface 14, for compensation or differential measurement by scanning the same surface 14 twice, etc.

[0029] For example, when the laser emitter 11 is a very small semiconductor laser, the laser emitter 11 can be directly located in the beam path of the received beam 15 between the mirror cone 2 and the laser receiver 16. However, in the example shown, the laser emitter 11 consists of a larger laser 18 located outside the received beam path and a small deflecting mirror 19, which is located in the received beam path between the mirror cone 2 and the laser receiver 16 and directs the laser beam 12 emitted from the laser 18 in a direction approximately parallel to the axis of rotation 2' towards the mirror cone 2.

[0030] In principle, the laser receiver 16 can be of any type known in the art, such as a large - format photosensitive element, a CCD chip, etc. In the example shown, the laser receiver 16 includes (at least) one converging lens 20 and a receiving element 21 arranged downstream in the received beam path and located at the focal point of the converging lens 20. The receiving element 21 is highly sensitive, for example a photomultiplier or an avalanche photodiode.

[0031] In the receiving optical path, a diaphragm 22 (here: semi-circular) is provided upstream of the converging lens 20, the function of which will be described in more detail below. The optical axis of the converging lens 20 coincides with the axis of rotation 2' of the mirror cone 2. The size of the converging lens 20 in combination with the diaphragm 22 (i.e., subtracting the part of the converging lens 20 obscured by the diaphragm 22), and the size of the corresponding active mirror surfaces 7 - 10, i.e., the smaller of the two sizes, determine the receiving aperture of the laser receiver 16. Instead of the combination of the converging lens 20 and the upstream diaphragm 22, the converging lens 20 can also simply be cut, i.e., the part of the converging lens 20 defined above by the diaphragm 22 can be "excised", whereby the converging lens 20 has a sector-shaped or (here) semi-circular shape.

[0032] As Figure 2 shown, the emitted beam 12 is, for example, a pulsed laser beam having a plurality of individual emitted pulses, which are emitted at the corresponding emitted pulse times t S,n , deflected by the mirror cone 2, reflected by the corresponding points U n of the surface 14, and received in the laser receiver 16 after being deflected back by the mirror cone 2 at the corresponding received times t E,n . Based on the pulse propagation time ΔT n = t E,n - t S,n , the

[0033] D n = c·ΔT n / 2 = c·(t S,n - t E,n ) / 2, (1)

[0034] where

[0035] t S,n ... is the emission time of the emitted laser pulse Sn,

[0036] t E,n ... is the reception time of the received laser pulse En, and

[0037] c......... is the speed of light The target distance D of the laser scanner 1 in the corresponding emission direction relative to the environmental target U n . n .

[0038] Figure 2 Is shown in a two-dimensional schematic simplified manner Figure 1The laser scanner 1 is installed in the housing 23. To allow the emission and reception beams 12, 15 to pass through, the housing 23 includes a window 24 made of a transparent material such as plastic or glass. The window 24 can be, for example, a large planar glass plate or have the shape of a cylindrical part and extend over the scanning angle α when viewed in the circumferential direction U( Figure 3b ) of the mirror cone 2. Since on the one hand the planar glass window 24 has to be very large to record the scanning angle α of the emission beam 12 and the reception beam 15, and on the other hand the production of a cylindrically curved glass window is complex, as shown in the figure, the glass window 14 is assembled from a plurality of planar parts 25, 26, 27 that are angled with respect to each other, for example, by bonding with an adhesive.

[0039] Figures 3a-3c Shows three rotational positions of the "active" mirror surface relative to the impact surface or emission aperture S (thick line shading) of the laser emitter 11 and the reception aperture E (dot-filled) of the laser receiver 16. The "active" mirror surface is the mirror surface 7 - 10 that is struck by the emission beam 12, here the mirror surface 7 (thin line shading). More specifically:

[0040] - In Figure 3a , the angular position of the active mirror surface 7 in which the emission aperture S has just passed through the edge 28 between the mirror surface 10 and the active mirror surface 7 and thus is completely located on the active mirror surface 7;

[0041] - In Figure 3b , the central position in which the active mirror surface 7 has been rotated such that the emission aperture S viewed in the circumferential direction is located at the center of the active mirror surface 7; and

[0042] - In Figure 3c , a position in which the emission aperture S has just still completely been located on the active mirror surface 7, that is, just before the emission aperture S passes through the edge 29 between the active mirror surface 7 and the adjacent mirror surface 8, thus making it "active".

[0043] Obviously, the laser emitter 11 is directed at the edge region 30 of the mirror cone 2, that is, the radial distance r of its impact point or emission aperture S relative to the axis of rotation 2' is maximized to the extent that the emission aperture S is just still located on the active mirror surface 7 in the radial direction. In addition, the diameter D of the emission aperture S S should be as small as possible relative to the circumferential extent L in the edge region 30 of the active mirror surface 7 U . For example, the diameter D of the emission aperture S S is less than the circumferential extent L in the edge region 30 of the corresponding active mirror surfaces 7 - 10 UOne quarter, especially less than one eighth thereof.

[0044] In order to avoid the emitted beam 12 passing through one of the respective bends between the parts 25 and 26 or 26 and 27 during the scanning movement at the scanning angle α, and being irregularly refracted or deflected there, the length L1 of the central part 26 as observed from the circumferential direction U of the mirror cone 2 is such that the emitted beam 12 deflected by the mirror cone 2 only passes through the central part 26. It should be understood that the length L1 depends on the distance between the mirror cone 2 and the central part 26, the inclination of the mirror surfaces 7 - 10 relative to the axis of rotation 2', and the radial distance r between the impact point of the emitted beam 12 on the mirror cone 2 and the axis of rotation 2'. The closer the glass window 14 is to the mirror cone 2, the farther radially the emitted beam 12 impacts on the mirror cone 2, and the shorter the length L1 of the central part 26 can be, and thus the shorter the glass window 14 as a whole.

[0045] The lengths L2 of the outer parts 25, 27 and their angle β relative to the central part 26 are preferably selected such that the received beam 15 reflected in a diffuse manner (i.e., in a relatively wide manner) by the ambient point U n can still impact on the entire mirror surface 7 on which the emitted beam 12 acts, also on the two outermost end positions of the emitted beam 12 on the acting mirror surface 7, as Figure 3a and 3c shown.

[0046] According to Figures 3a-3c , as observed from the direction of the axis of rotation 2', i.e., in the projection onto a projection plane perpendicular to the axis of rotation 2' (the drawing plane here), the receiving aperture E (filled with dots) of the laser receiver 16 is approximately twice the size of one of the mirror surfaces 7 - 10 (thin - line shaded). When the mirror surfaces 7 - 10 of the mirror cone 2 have different inclinations to produce different scanning fans 13, 17, their sizes are usually different when viewed from the direction of the axis of rotation 2'. In this case, the receiving aperture E of the laser receiver 16 is preferably approximately twice as large as the size of the largest mirror surface as observed in the direction of the axis of rotation 2' among all the mirror surfaces 7 - 10.

[0047] By using such a large receiving aperture E, the laser receiver 16 can Figures 3a to 3c utilize and receive all the received beams 15 received back and deflected from the acting mirror surface, such as the mirror surface 7 here, at each position of the mirror cone 2 shown in Figure 1 shown. This is achieved, for example, by the converging lens 20 shown in Figure 3a and 3cIn the top view, the converging lens substantially overlaps two adjacent mirror surfaces 7 - 10. In this way, it is ensured that even at the two end positions of the emission aperture S on the active mirror surface 7 ( Figure 3a and 3c ), the entire surface area of the active mirror surface 7 can be utilized to receive the received beam 15 without cutting the received beam.

[0048] In principle, the receiving aperture E (viewed along the direction of the rotation axis 2') can also be greater than twice the largest mirror surface, i.e., for example, it can cover the entire mirror cone 2, i.e., the diaphragm 22 can be omitted. However, this does not further increase the receiving sensitivity of the laser scanner 1 because only the received beam 15 that impinges on the corresponding active mirror surface 7 and is incident from the emission direction of the emission beam 12 of interest is the useful beam. For example, by omitting the diaphragm 22, an increase in the receiving aperture E viewed in the direction of the rotation axis 2' exceeds the surface area of the two mirror surfaces 7 - 10, so the receiving sensitivity is no longer increased. Instead, it may cause interference signals acting on the laser receiver 16, for example, when the emission and received beams 12, 15 impinge on the rear non - active mirror surfaces ( Figure 3a mirror surfaces 8, 9 in Figure 3b mirror surface 9 and Figure 3c mirror surfaces 9, 10 in

[0049] On the contrary, the receiving aperture E can also be in the range between one times and two times the surface area of the mirror surfaces 7 - 10 (especially the largest one) viewed along the direction of the rotation axis 2', where the receiving sensitivity of the laser scanner 1 near the Figure 3a and 3c end positions is correspondingly reduced because the receiving aperture E can no longer detect the entire active mirror surface 7 or "partially cuts" this mirror surface. Nevertheless, compared with traditional laser scanners, especially at least near the Figure 3b central position, the receiving sensitivity of the laser scanner 1 is also increased here.

[0050] The increase in the receiving sensitivity of the laser scanner 1 can be used to increase its range, so that remote environmental targets U that only reflect weak received beams 15 can also be measured n .

[0051] The present invention is not limited to the illustrated embodiments, but includes all variations, modifications, and their combinations that fall within the scope of the appended claims.

Claims

1. A laser scanner (1), comprising: a housing (23), a laser emitter (11) including an emission aperture (S) for emitting an emission beam (12), a laser receiver (16) for receiving the emission beam (12) reflected by the environment as a received beam (15), and a beam deflection device, which is located in the beam path of the emission and received beams in the form of a mirror cone (2) mounted on a rotatable shaft (3), wherein the cone axis of the mirror cone forms a rotation axis (2'), and each of the respective cone sides of the mirror cone inclined to the rotation axis (2') forms a mirror surface (7 - 10), the laser emitter (11) and the laser receiver (16) each point at the mirror cone (2) substantially parallel to the rotation axis (2') of the mirror cone (2), and the laser receiver (16) has at least one converging lens (20), which is arranged downstream of the mirror cone (2) in the received beam path, characterized in that in the region where the converging lens (20) overlaps with the mirror surfaces (7 - 10), the converging lens (20) observed in the direction of the rotation axis (2') is at least twice as large in area comparison as the largest mirror surface among all the mirror surfaces (7 - 10) observed in the direction of the rotation axis (2').

2. The laser scanner according to claim 1, characterized in that in the region where the converging lens (20) overlaps with the mirror surfaces (7 - 10), the converging lens (20) observed in the direction of the rotation axis (2') is twice as large in area comparison as the largest mirror surface among all the mirror surfaces (7 - 10) observed in the direction of the rotation axis (2').

3. The laser scanner according to claim 1, characterized in that the converging lens (20) is circular when observed in the direction of the rotation axis (2'), the optical axis of the converging lens lies on the rotation axis (2'), and a diaphragm (22) is arranged upstream of the converging lens (20).

4. The laser scanner according to claim 3, characterized in that the mirror cone (2) has four mirror surfaces (7 - 10), and the diaphragm (22) has a semi - circular shape when observed in the direction of the rotation axis (2').

5. The laser scanner according to claim 1, characterized in that the converging lens (20) is fan - shaped when observed in the direction of the rotation axis (2'), and the optical axis of the converging lens lies on the rotation axis (2').

6. The laser scanner according to claim 5, characterized in that the mirror cone (2) has four mirror surfaces (7 - 10), and the converging lens (20) has a semi - circular shape when observed in the direction of the rotation axis (2').

7. The laser scanner according to any one of claims 3 to 6, characterized in that The laser receiver (16) comprises a receiving element (21) which is arranged in the focal point of the converging lens (20).

8. The laser scanner according to any one of claims 1 to 6, characterized in that the laser transmitter (11) comprises a deflecting mirror (19) in the receiving beam path between the mirror cone (2) and the laser receiver (16), and a laser (18) which is directed at the deflecting mirror (19) and is located outside the receiving beam path.

9. The laser scanner according to any one of claims 1 to 6, characterized in that the laser transmitter (11) is directed at the edge region (30) of the bottom side of the mirror cone (2).

10. The laser scanner according to claim 9, characterized in that The diameter (D S ) of the emission aperture (S) of the laser emitter (11) at the level of a mirror surface (7-10) is less than a quarter of the circumferential extent (L U ) of the mirror surface (7-10) in the edge region (30).

11. The laser scanner according to any one of claims 1 to 6, characterized in that The housing (23) includes a window (24) that points to the circumference of the mirror cone (2) and is made of a transparent material for the transmitted beam and the received beam (12, 15) to pass through. The window is divided into at least three parts (25 - 27) that are angled relative to each other when viewed in the circumferential direction (U) of the mirror cone. The length (L 1 ) is at least such that the transmitted beam (12) deflected by the mirror cone (2) only passes through the central part (26).

12. The laser scanner according to any one of claims 1 to 6, characterized in that at least two mirror surfaces (7 - 10) of the mirror cone (2) have different inclinations.

13. The laser scanner according to claim 7, characterized in that the receiving element is in the form of a photomultiplier or an avalanche photodiode.

14. The laser scanner according to claim 9, characterized in that the diameter of the emission aperture of the laser transmitter at the level of a mirror surface is less than one - eighth of the circumferential extent of the mirror surface in the edge region.

Images