WO2019020532A1

WO2019020532A1 - Lidar device and method with improved deflecting device

Info

Publication number: WO2019020532A1
Application number: PCT/EP2018/069823
Authority: WO
Inventors: Axel Buettner; Jan MERTENS; Annette Frederiksen
Original assignee: Robert Bosch Gmbh
Priority date: 2017-07-27
Filing date: 2018-07-20
Publication date: 2019-01-31
Also published as: DE102017212926A1

Abstract

The invention relates to a LIDAR device for scanning a scanning area with a statically arranged laser for producing at least one beam, comprising a deflecting device that can be rotated along an axis of rotation, for deflecting the at least one produced beam into the scanning area, and a receiving optical element for receiving and deflecting the at least one beam reflected by an object onto a detector, the deflecting device comprising an optical waveguide with at least two parallel glass fibres, the at least two parallel glass fibres being arranged such that they are staggered in relation to each other on an output side of the optical waveguide. The invention further relates to a method for operating a LIDAR device.

Description

Description title

LIDAR device and method with an improved deflection device

The invention relates to a LIDAR device for scanning a

Scanning area and a method for operating such a LIDAR device.

State of the art

In LIDAR (light detection and ranging) devices, in particular, a distance between the LIDAR device and an object is determined. For this purpose, a beam is generated by a laser and emitted into a scanning region. By means of a deflection device, the beam can be deflected distributed over the scanning area. The reflected beam on an object can then be received by a receiving optical system and directed to a detector. For this purpose, different concepts are pursued. In addition to the so-called

"Microscanners" are also used as "macroscanners". rotating

Macroscanners may be constructed such that the laser and the detector are statically arranged. The deflection device consists here of a pivotable mirror which deflects the generated beam into the scanning region. In this case, the deflection unit also directs the rays reflected by an object onto the detector. As a result, no energy and data transmission to the rotating parts is needed. From DE 10 201 1 107 594, such a LIDAR device is known which uses a rotating mirror for deflecting the generated beams. In these concepts, however, is the horizontal

Field of View, so that 360 ° coverage can only be realized with multiple optical elements, resulting in a complex setup and adjustment, and the resolution in the vertical direction is limited by the number of discrete lasers. Disclosure of the invention

The object underlying the invention can be seen to suggest a LIDAR device and a method for scanning as large a scanning as possible with reduced complexity.

This object is achieved by means of the subject matter of the independent claims. Advantageous embodiments of the invention are the subject of each dependent subclaims.

According to one aspect of the invention, a LIDAR device for scanning a scan area is proposed. The LIDAR device comprises a statically arranged laser for producing at least one steel, a deflection device rotatable along an axis of rotation for deflecting the at least one generated beam into the scanning region and one

Receiving optics for receiving and deflecting the at least one beam reflected at an object on a detector. According to the invention, the deflection device has an optical waveguide with at least two parallel glass fibers, wherein the at least two parallel glass fibers are arranged offset from one another at an exit side of the optical waveguide.

By using an optical waveguide as a deflector or as part of the deflector in the transmit path of the generated beam, the complexity of a LIDAR device can be reduced. The optical waveguide here consists of at least two glass fibers that can guide or deflect the beam generated. The at least two glass fibers can be one

Have shell and arranged side by side or bundled. The glass fibers may for example consist of a plastic or a glass and alternatively have no sheath. The respective ones

Glass fibers may be uncoated or at least partially coated. An optical waveguide may comprise one or more glass fibers which form a common core or a plurality of separate cores of the optical waveguide. The respective cores or glass fibers can over a length of the Optical waveguide be arranged constant or have a variable arrangement along the length of the optical waveguide. For example, the glass fibers may be arranged side by side at one entrance side and be spaced apart on an exit side of the optical waveguide and form a so-called "bi-furcated fiber" or "multi-furcated fiber".

Preferably, the respective optical fibers of the optical waveguide can carry light in any form loss. On a side facing the laser, the optical waveguide has an entry side. Here, the generated beam can be coupled into the optical waveguide. Coupling means here that the generated beam transmits as completely as possible into the glass fibers of the optical waveguide. Preferably, the generated beam is simultaneously in the

By coupling the at least one beam is divided into at least two partial beams, which can be guided in each case by a glass fiber at least two glass fibers of the optical waveguide. The

Optical waveguides can be bent, for example, at a 90 ° angle and be positioned in a rotating housing or in the rotatable deflection device. Thus, the generated beam split into at least two sub-beams may be directed to one side toward the scanning area. On the exit side of the optical waveguide, the partial beams leading glass fibers are arranged vertically one above the other, so that the at least two partial beams can vertically decouple from each other from the optical waveguide. By the

Decoupling from the optical waveguide, the generated beam leaves the glass fibers of the optical waveguide according to the orientation of the glass fibers. In this way, depending on the number of partial beams or glass fibers, a larger vertical range can be scanned or a vertical resolution can be increased. On the exit side of the optical waveguide, the individual

Glass fibers at an angle to each other or be spaced from each other. As a result, a vertical resolution or a vertical scanning angle can be set. Alternatively or additionally, the optical waveguide may for example be a so-called "multi-branch-fiber" or a "multi-furcated fiber". In this way, a multiplicity of glass fibers can be arranged one above the other or offset relative to one another on the exit side of the optical waveguide. Alternatively or additionally, the glass fibers can also be arranged horizontally or diagonally next to one another on the outlet side, so that, in addition to a larger vertical scanning region, a horizontal scanning region is faster can be sampled. Alternatively or additionally, by bending a region of the optical waveguide instead of rotating the entire optical waveguide, the optical waveguide can deflect the at least one generated beam along the scanning region.

According to an embodiment of the LIDAR device, the entrance side of the optical waveguide forms the axis of rotation. The laser generates a beam that passes through the axis of rotation. As a result, the structure of the LIDAR device can be simplified and downsized. The generated beam or

Laser beam is as well as the entrance side of the optical waveguide in the axis of rotation, so that the generated beam can be coupled without further technical aids in the optical waveguide. Alternatively, to

Coupling the generated beam in the optical waveguide optics or a lens are used. Thus, the beam can be independent of a

Rotation direction and speed are coupled into the optical waveguide.

According to a further embodiment of the LIDAR device, the glass fibers are arranged bundled on the inlet side of the optical waveguide. Thus, a laser may be stationary or not rotatable positioned and the at least one beam generated a lens or directly into the

Coupling in the optical waveguide. Due to the bundled arrangement of the glass fibers on the inlet side of the optical waveguide, the at least one generated beam can be coupled into all optical fibers simultaneously. In addition, in this case, a cross section of the respective glass fibers on the inlet side of the

Fiber optic reduced or enlarged. Preferably, the

Glass fibers bundled rotationally symmetrically arranged at the inlet side. This allows the at least one beam at any time in a rotating

Fiber optic cables are coupled. The cross section can in this case be varied both by a distributed or bundled arrangement of the respective glass fibers and by a cross section of the respective glass fibers.

According to a further embodiment, the glass fibers each have their own transmitting optics on the exit side of the optical waveguide. The individual or selected glass fibers can be used with a micro-lens directly be printed or equipped on a fiber facet. This can

For example, an image in a far field as a point or line allows. These lenses printed on the fiber facet may have a

Replace transmission optics. A printing of such an objective can be realized, for example, by 2-photon lithography.

According to a further embodiment, the glass fibers on the outlet side of the optical waveguide on a common transmission optics. As a result, a LIDAR device can be of a particularly simple design, since only one common transmission optics is required. As a result, less

Components are necessary, such a LIDAR device can be designed to save space.

According to another embodiment of the LIDAR device is the

Deflection device rotatable along a 360 ° angle. By rotating the deflection device through 360 °, light or the at least one generated beam can be emitted in all directions, so that a horizontal scanning range of 360 ° is made possible. The vertical scanning area or field of view can be defined by the number of optical fibers, their orientation or spacing from one another and in conjunction with the transmitting optics and the detector resolution.

According to a further embodiment, the vertically stacked glass fibers on the exit side of the optical waveguide form a linear laser beam. Preferably, the individual from the

Fiber optics in the scanning decoupled beams are combined by suitable transmission optics to a vertically aligned line so that a divergence of the line defines the vertical scanning angle or field of view. The line can be realized either by expanding at least one beam using optical elements such as cylindrical lenses or by positioning a plurality of optical fibers on top of each other. As a result, a high vertical resolution of the scanning area can be realized on the detector. According to a further embodiment of the LIDAR device, the detector is designed annular and arranged statically around the laser. Here is the

Detector annularly arranged around the laser and optically isolated. Rays reflected or scattered by an object are collected by a receiving optic mounted in the rotating deflector and deflected by a mirror also disposed in the deflector onto the annular detector. The rays thus received are imaged linearly on the detector at a rotational speed of the deflection device. Based on the movement of the deflection device, an active area on the detector can also be controlled in a variable manner without having to move the detector itself. Alternatively, an integration of the optical waveguide in the receiving optics is possible, although a vertical

aligned "blind spot" arises in the detection, but which can be compensated by a rotation of the deflection device

Integration allows a nearly coaxial design of the LIDAR device, which reduces the height of the LIDAR device and optical

Parallax errors can be minimized. The deflection device can thus serve both to guide and deflect at least one generated beam and to receive and deflect at least one reflected beam.

According to a further embodiment, the detector is arranged statically next to the laser or on a side of the device opposite the laser. For example, the detector may be implemented as a 2D array.

For this purpose, the detector may be arranged parallel to the laser. About a receiving optics, which has a mirror and on the rotatable

Ablenkvorrichtung is arranged, reflected rays along a limited scanning range can be directed to the detector. Alternatively, the detector may be disposed in the axis of rotation and positioned on a side of the LIDAR device opposite the laser. Thereby, the reflected beams can be received and detected unrestrictedly along a horizontal 360 ° scanning range. According to a further embodiment, the detector is in the

Deflecting arranged. As an alternative to a stationary embodiment of a detector, the detector can be rotatably arranged or integrated in the deflection device. In this case, the detector can be constructed technically simpler, since a line detector is already sufficient. The received beams are imaged on the line detector, so that an optimal use of the available detection pixels can be ensured.

According to another aspect of the invention, there is provided a method of operating a LI DAR device. Here, at least one beam of one

Laser generated and coupled into a deflector. The at least one beam is deflected by the deflection device and along a

Scanned angle emitted. For this purpose, the at least one generated beam is coupled into a deflected device arranged in the optical waveguide with at least two glass fibers for deflecting. On an exit side of the

Optical waveguide, the at least one generated beam can be coupled out of the at least two glass fibers as at least two offset partial beams. The deflection device in this case has an optical waveguide with at least two

Glass fibers on. The beams can be coupled into the respective glass fibers, which can form a common core or separate cores of the optical waveguide. The glass fibers guide the coupled beams over a defined angular range and thus deflect at least one generated beam. At an exit side of the optical waveguide, the at least one coupled beam can leave the optical waveguide. The optical waveguide is also rotatable as part of the deflection device and can thus deflect the at least one generated beam along a scanning region. Preferably, an entry region of the optical waveguide is positioned in an axis of rotation of the deflection device. The laser is in this case arranged such that a generated beam also extends through the axis of rotation and can be coupled into the optical waveguide. In this case, the optical waveguide with the at least two glass fibers as one or more cores of the optical waveguide fulfills the function of a beam splitter which can receive, guide and divide at least one generated beam. At the exit side of the Optical waveguide, the respective glass fibers can be spaced from each other and / or angularly offset from each other. As a result, several partial beams are generated, which are used for vertical or horizontal scanning of

Scanning area can be used. Thus, a vertical resolution of a LIDAR device can be increased or a larger vertical range can be scanned without additional control effort.

The following are based on highly simplified schematic

Representations preferred embodiments of the invention explained in more detail. Show here

Fig. 1a is a schematic representation of an optical waveguide of a

Deflection device according to a first embodiment,

Fig. 1 b is a schematic representation of the optical waveguide a

Deflection device according to a second embodiment,

2 shows a schematic representation of a transmission optical system of the optical waveguide of a deflection device according to a third exemplary embodiment, FIG. 3 shows a schematic illustration of a LIDAR device according to a first exemplary embodiment,

Fig. 4 is a schematic representation of a LIDAR device according to a second embodiment and

Fig. 5 is a schematic representation of a LIDAR device according to a third embodiment.

In the figures, the same constructive elements each have the same reference numerals.

FIGS. 1 a and 1 b each show optical waveguides 1. The optical waveguides 1 are arranged in a deflecting device shown in FIG. 3 and numbered. The optical waveguides 1 have an entrance side 2 for coupling in of rays and an exit side 4 for decoupling of rays. According to a first exemplary embodiment, the optical waveguide 1 has two glass fibers 6 and is a so-called "bifurcated fiber." The glass fibers 6 each form a core of the optical waveguide 1. The glass fibers 6 are arranged bundled on the inlet side 2. On the outlet side 4 are the Glass fibers 6 from each other spaced and have an angle to each other. Thus, a coupled into the optical waveguide 1 beam can be divided by the two glass fibers 6 into two sub-beams and fanned out at a decoupling. In contrast to the first exemplary embodiment, the optical waveguide 1 according to the second exemplary embodiment has a large number of glass fibers 6.

In this case, the optical waveguide 1 is designed in the form of a so-called "multi-branch fiber".

FIG. 2 shows a glass fiber 6 of an optical waveguide 1. Here, the outlet side 4 of the optical waveguide 1 is shown enlarged. On a

Glasfaserfacette is printed on a transmission optics 8, which can focus or expand a beam at a decoupling. Each optical fiber 6 may each have such a transmission optical system 6. FIG. 3 shows a schematic representation of a LIDAR device 10 according to a first exemplary embodiment. The LIDAR device 10 has a laser 12 which generates a beam 14. The generated beam 14 is coupled on the inlet side 2 in the optical waveguide 1. The optical waveguide 1 is positioned in the rotatable deflection device 16 and has a bend of 90 °. The deflection device 16 can by not shown actuators or

Motors are rotated about a rotation axis R. In this case, the optical waveguide 1 is arranged in the deflection device 16 such that the entry side 2 lies in the axis of rotation R. Since the laser 12 is also located in the axis of rotation R, generated beams 14, regardless of rotation of the

Deflection device are coupled into the optical waveguide 1. An objective 18 focuses the generated beam 14 on the bundled glass fibers 6 on the inlet side 2 of the optical waveguide 1. By the bending of the optical waveguide 1 coupled beams follow the shape of the optical waveguide 1 and are also deflected by 90 ° on the exit side 4 of the optical waveguide. 1 decoupled. Since the glass fibers 6 on the exit side 4 are arranged vertically one above the other, the generated beam 14 is split into a plurality of partial beams 20, which are fanned over a vertical scanning area. Thus, a larger vertical scanning area can be exposed. The deflection device 16 also has a receiving optics 22. The reflected at an object 24 partial beams 26 are received by the receiving optics 22 and Reflected via a also positioned in the deflector 16 mirror 28 to a detector 30. In this case, the reflected beams 20 become received beams 32, which are directed onto the detector 30. The detector 30 according to the embodiment is a ring detector, which is arranged around the laser 12 around and is carried out with the laser 12 stationary or immovable.

In the figure 4 is a LIDAR device 10 according to a second

Embodiment shown. In contrast to the first exemplary embodiment, the LIDAR device 10 has a detector 30, which is designed in the form of a 2D array 30. The detector 30 is arranged according to the embodiment on an opposite side of the laser 12. For this purpose, the deflection device 16 to a receiving optics 22 and a mirror 28, which are arranged to deflect the reflected beams 26 of the laser 12 from. The detector 30 is located in the axis of rotation R and may be rotationally symmetrical. Thus, reflected rays 26 and subsequently received rays 32 may be directed to the detector 30. In this case, only the orientation of the received beams 32 on the detector 30 varies since this is located outside of the deflection device 16 and thus stationary.

FIG. 5 illustrates a LIDAR device 10 according to a third exemplary embodiment. Unlike the ones already mentioned

Embodiments, the detector 30 is in or on the rotatable

Deflection device 16 is arranged. Here, the detector 30 is a line detector

30, which detects the received beams 32 in situ and during rotation of the deflection device 16, respectively.

Claims

claims

LIDAR device (10) for scanning a scanning area with a statically arranged laser (12) for producing at least one steel (14), with a deflection device (16) rotatable along an axis of rotation (R) for deflecting the at least one generated beam ( 14) in the scanning region and with a receiving optical system (22) for receiving and deflecting the at least one beam (26) reflected at an object (24) onto a detector (30), characterized in that the deflection device (16) comprises an optical waveguide (16). 1) with at least two parallel glass fibers (6) as at least one core of the optical waveguide (1) and that the

at least two parallel glass fibers (6) on an exit side (4) of the

Optical waveguide (1) are arranged offset from each other.

2. Device according to claim 1, wherein an inlet side (2) of the optical waveguide (1) forms the axis of rotation (R) and the laser (12) generates a beam (14) which passes through the axis of rotation (R).

3. Device according to claim 1 or 2, wherein the glass fiber (6) on the

Entry side (2) of the optical waveguide (1) are arranged bundled.

4. Device according to one of claims 1 to 3, wherein the glass fiber (6) on the outlet side (4) of the optical waveguide (1) each have their own transmitting optics (8).

5. Device according to one of claims 1 to 4, wherein the glass fiber (6) on the outlet side (4) of the optical waveguide (1) have a common transmission optics (8).

6. Device according to one of claims 1 to 5, wherein the deflection device (16) is rotatable along a 360 ° angle.

, Device according to one of claims 1 to 6, wherein the vertically stacked glass fibers (6) on the outlet side (4) of the optical waveguide (1) form a linear beam (20).

, Apparatus according to any one of claims 1 to 7, wherein the detector (30) is annular shaped and statically disposed about the laser (12).

, Device according to one of claims 1 to 8, wherein the detector (30) is arranged statically next to the laser (12) or on a side of the device (10) opposite the laser (12).

Device according to one of claims 1 to 9, wherein the detector (30) in the deflection device (16) is arranged.

A method of operating a LI DAR device (10) according to any one of the preceding claims, wherein

at least one beam (14) is generated by a laser (12) and coupled into a deflection device (16),

the at least one beam (14) is deflected and radiated by the deflection device (16) along a scanning angle, at least one beam (26) reflected by an object (24) is directed by a receiving optical system (22) onto a detector (30),

characterized in that the at least one generated beam (14) is coupled into an optical waveguide (1) arranged in the deflection device (16) with at least two glass fibers (6) for redirecting the generated beam (14) and at an exit side (4) of the Optical waveguide (1) of the at least one generated beam (14) from the at least two glass fibers (6) as at least two mutually offset partial beams (20) is coupled out.