DE102017125686A1 - Optical scanner - Google Patents

Abstract

The invention relates to an optical scanner having at least one transmitting element and at least one panoramic receiving unit and a control and evaluation unit for evaluating the light transit time of light beams from the transmitting element via an object to the receiving element, wherein a plurality of transmitting elements are arranged in a common housing, the light beams fan-shaped in different angular directions through a convex surface on an outside of the housing can send out. The optical scanner according to the invention is characterized in that the fan-shaped receiving beams can be received with a panoramic receiving unit over an angle up to 360 °.

Description

The present invention relates to an optical scanner according to the preamble of claim 1.

A generic optical scanner has the following components: at least one transmitting element and at least one panoramic receiving unit and a control and evaluation unit for evaluating the light transit time of light beams from the transmitting element via an object to the receiving element, wherein a plurality of transmitting elements are arranged in a common housing, the light beams in different angular directions can fan out through a convex surface on an outside of the housing.

EP 2 237 063 B1 and EP 2 237 064 B1 disclose optical scanner with a rotating device on which a light source, a detector and parts of the evaluation unit are arranged. The rotating device serves to rotate a beam direction of the transmitted light pulses about an axis of rotation oriented transverse to the beam direction. The light pulses reflected by objects in the monitoring area are detected with the aid of the detector. The evaluation unit is used to control the light source, to evaluate the detected by the detector light pulses and to determine an object distance due to a measured transit time of the light pulses.

Because of the rotation of the transmitted light beam and because as a rule lasers are used as light sources, such devices are also referred to as laser scanners, laser radar or two-dimensional laser measuring devices. Sensors of this type have been used mainly in the industry for a variety of different tasks.

Generic devices are used for navigating, for example, forklifts, this often with the aid of reflectors or absorbers, which are attached to defined locations in the environment. In principle, however, it is also possible to navigate without reflectors, with the respective circumstances of the surroundings also being read into the evaluation unit in a learning phase.

Further applications exist for tasks in the field of obstacle detection, the protection of buildings, in the protection of persons, the volume measurement of objects, in principle therefore in all problems in which it is about the detection of object contours in any way.

Sensors of the type described are basically known and differ essentially with regard to the range, the scan area and the measured value processing used in each case.

For the optical scanners of in EP 2 237 063 B1 and EP 2 237 064 B1 a rotating measuring head with transmitted light source and detector is used to rotate the transmission beam in the measuring plane.

In EP 2 910 970 B1 a laser scanner with a variety of transmitters and receivers, and optical components without moving parts is disclosed.

As an object of the invention can be considered to provide a simple and inexpensive sensor that does not require mechanical moving parts, is not subject to mechanical wear and has a long life.

These objects are achieved according to the invention by the optical scanner having the features of patent claim 1. Advantageous embodiments of the method according to the invention are specified in subclaims.

According to the invention, the optical scanner of the type specified above is further developed in that the fan-shaped receiving beams can be received by a panoramic receiving unit over an angle of up to 360 °.

As a core idea of the invention can be considered, in contrast to the prior art to provide an optical sensor according to the transit time principle in which a technically simple means with as small a number of components, a scan range of up to 360 ° is made possible.

Thereafter, the invention provides that the optical scanner includes at least one transmitting element and at least one panoramic receiving unit and a control and evaluation unit for evaluating the light transit time of light beams from the transmitting element via an object to the receiver.

A particularly preferred variant of the optical scanner according to the invention is characterized in that the panoramic receiving unit uses rotationally symmetrical reflecting surfaces and / or lenses and / or diaphragms for guiding the light.

A further particularly preferred variant of the optical scanner according to the invention is characterized in that the panoramic receiving unit contains a catadioptric optical system.

Another particularly preferred variant of the optical scanner according to the invention is characterized in that the reflection in the catadioptric optics is produced by total reflection.

Another particularly preferred variant of the optical scanner according to the invention is characterized in that the transmitting elements are arranged in a full circle.

Another particularly preferred variant of the optical scanner according to the invention is characterized in that the transmitting elements are arranged on a flexible printed circuit board.

Another particularly preferred variant of the optical scanner according to the invention is characterized in that the transmitting elements are arranged in a matrix with at least two rows.

A further particularly preferred variant of the optical scanner according to the invention is characterized in that at least one transmitting element is arranged per angular degree.

A further particularly preferred variant of the optical scanner according to the invention is characterized in that the transmitting elements are arranged on at least two circles of different diameters and / or not equidistant to the angle.

Another particularly preferred variant of the optical scanner according to the invention is characterized in that the transmitting elements are arranged on an at least partially rigid part-circular, circular section-shaped, circular, partially cylindrical, cylindrical, partially spherical, spherical section-shaped or spherical plastic carrier with integrated circuit boards.

A further particularly preferred variant of the optical scanner according to the invention is characterized in that at least one lens and / or one microlens is arranged in front of each transmitting element.

Another particularly preferred variant of the optical scanner according to the invention is characterized in that the lenses or microlenses form a lens system.

A further particularly preferred variant of the optical scanner according to the invention is characterized in that the control and evaluation unit has a logic module, in particular of the CPLD (Complex Programmable Logic Device) or FPGA (Field Programmable Gate Array) type.

Preferably, a plurality of transmitters are arranged on a circle or pitch circle in a row in a common housing, wherein the light beams are fan-shaped in different angular directions and / or received. The distances of the transmitted light beams increase with increasing distance from the optical scanner and the distances of the received light beams become smaller with decreasing distance to the optical scanner.

In a particularly preferred embodiment, the optical axes of the emitted light beams intersect in a common origin, for example a point-like origin within the optical scanner.

In a further embodiment of the invention, the transmitters can also be arranged on different circles or partial circles, so that a smaller distance is possible between the optical axes of the transmitters and the angle between the transmit beams becomes lower, which leads to a higher angular resolution of the optical scanner , The circles or pitch circles on which the transmitters are located are preferably arranged concentrically.

The transmitters are preferably arranged on a circle or pitch circle such that their optical axes extend at equidistant angles. An embodiment in which the optical axes of the transmitters are not arranged equidistant in terms of angle makes it possible to adjust the angular resolution of the optical scanner in regions.

Perpendicular to the optical axes of the transmitter runs through this origin an imaginary axis that defines the scanning plane. This axis is preferably almost perpendicular to the detector of the panoramic receiving unit. The panoramic receiving unit is preferably arranged symmetrically about this axis.

The panoramic receiver unit includes at least one optic that allows up to 360 ° viewing angle and a receiver. For a viewing angle of 360 ° omnidirectional mirrors can be used. Other optical components such as lenses and apertures can be added as needed. Preferably, catadioptric systems are used for the receiving optics. These systems direct the light through reflection and refraction to the receiver. The reflection can also be achieved by total reflection at appropriately shaped interfaces. Such systems are known and described for example in Ryad Benosman, Sing Bing Kang "Panoramic Vision", ISBN 0-387-95111-3.

A windscreen of the optical scanner forms the housing closure. The windshield preferably has a convex surface on the outside of the housing. The transmitted light rays are emitted fan-shaped diverging. According to the invention, the light beams are fan-shaped in different angular directions, whereby a surveillance area can be easily examined as to whether or not objects are present in the surveillance area and at which location, ie at which distance the objects are present. Furthermore, the objects can be measured, or an environmental contour and its change can be detected. Due to the fan-shaped emission of the light beams, or the fan-shaped receiving the surveillance area is monitored within a fan-shaped plane.

The panoramic receiving unit is located in a plane below or above the level of the transmitter. The fan-shaped incident light is directed from the panoramic receiver to the receiver. As a receiver, photodiodes, in particular PIN or avalanche diodes come into question. The receiver can also be constructed as a matrix of individual receivers.

The optical scanner can be manufactured with high accuracy, since the transmitting elements are firmly fixed and the light rays enter directly without moving parts in the monitoring area. In the production of the optical scanner, the angular accuracy of the angular directions of the transmitting elements can be checked and adjusted. This ensures that each optical scanner meets a certain required angular accuracy.

The optical scanner according to the invention is therefore simple and inexpensive. Since the optical scanner does not require any mechanically moving parts, it has no mechanical wear and has a long service life. For example, a required service life of, for example, about 20 years can be met with the optical scanner according to the invention.

Since the laser scanner requires no moving parts, which may be exposed to accelerations, for example when used in vehicles, the optical scanner according to the invention is almost insensitive to vibration and shock loads and can therefore be used without problems in moving objects such as vehicles, especially industrial trucks and driverless transport systems.

The fact that the optical scanner manages without moving parts, the optical scanner can also be made very compact.

For the transmitting elements z. For example, VCSEL laser diodes or power LEDs can be used. The transmission light or transmission signal may be pulsed, whose light transit time is evaluated.

The transmit light or transmit signal can also be modulated, for example, in order then to determine its phase position relative to the received reflex signal and to calculate therefrom the distance of the object.

In a preferred embodiment, the transmitting elements are arranged equidistantly along the pitch circle. This ensures a uniform resolution of the laser scanner for the detection of objects. Depending on the desired resolving power of the laser scanner, the transmitting elements can be arranged at equidistant or angular intervals equidistantly.

In a development of the invention, the transmitting elements are arranged in a matrix with at least two rows. As a result, the previously fan-shaped monitored in a plane monitoring area is extended in a further dimension, so that according to the embodiment of the invention, a part-cylindrical monitoring area can be monitored. This structure can be extended to increase the surveillance area.

In a particular embodiment, the transmitting elements are arranged in a full circle. As a result, an annular or a hollow cylindrical monitoring area can be realized. Advantageously, this realizes a protective field with an angular extent of 360 °. The light beams are emitted in an angular range of 360 ° from the transmitting elements and received in an angular range of 360 ° from the panoramic receiving unit.

For example, a single line element with transmitters is arranged in a 360 ° full circle. In this case, the substrate of the line elements is made so thin that the line element can adapt to a curvature of the full circle.

In a further development of the invention, the transmitting elements are arranged on a flexible printed circuit board. As a result, the optical scanner can be produced very inexpensively. The flexible circuit board is equipped in a first step with the transmitting elements. Subsequently, the flexible printed circuit board is mounted on a pitch circle cylinder or a cylinder, so that the transmitting elements are arranged in a circle-shaped or part-circular manner.

In a further development of the invention, the transmitting elements are arranged on a rigid partially or completely part-circular, circular section-shaped, circular, partially cylindrical, cylindrical, part-spherical, spherical section-shaped and / or spherical plastic carrier with integrated circuit boards. The rigid plastic carrier is a three-dimensional rigid printed circuit board, which is equipped directly with the transmitting elements or the receiving elements. For example, the plastic carrier can be produced as a highly integrated MID part (Molded Interconnected Device or injection-molded circuit carrier). Molded interconnect devices, MID for short, are electronic components in which metallic interconnects are integrated on and inside injection-molded plastic substrates.

In a further development of the invention, at least one transmitting element is arranged per angular degree. As a result, at least one distance measurement is available per degree of angle. If more than one transmit element is used, the resolution is further increased. For example, with a pixel width of 15 μm and a cylinder radius of 20 mm, an angular resolution of 0.43 ° can be achieved.

In a further development of the invention, at least one lens or microlens is arranged in front of each transmitting element. By the microlens emanating from the transmitting element light beam is appropriately focused, whereby a light beam diameter can be influenced and the light beam can be energetically concentrated.

The lenses or microlenses may be refractive or diffractive lenses. Preferably, the optical axes of the lenses or microlenses have a common origin, or a common punctiform origin in the housing of the optical scanner.

In a further development of the invention, the lenses or microlenses form a lens system. The lens system consists for example of a plurality of successively arranged lenses, which are either assigned to a single transmitting element, or it can also be provided according to the embodiment of the invention that a lens system is arranged as a system optics in front of several transmitting elements.

The transmission elements are controlled by the control and evaluation unit. In particular, this may be a logic module, in particular of the CPLD (Complex Programmable Logic Device) or FPGA (Field Programmable Gate Array) type. The control and evaluation unit can also be formed by a DSP (Digital Signal Processor).

The control of the transmission elements can be segmented and / or sequential. By simultaneously controlling several transmitters in a transmitter group, the monitoring range and the resolution can be specified. For an overview measurement, it may be useful to interconnect several transmitters in a first measurement and to increase the angular resolution in the subsequent measurements by activating individual transmitters.

The receiver is evaluated synchronously with each controlled transmission element or transmitter group.

According to the invention, however, a separate control unit and a separate evaluation unit can also be provided for the transmitting elements and for the receiving elements, which are connected to one another via an interface.

• 1 eine schematische Ansicht eines optischen Scanners mit Sendeelementen und Panorama-Empfangseinheit;
• 2 der optische Scanner aus 1 in einer schematischen Seitenansicht;
• 3 Ausführungsbeispiele von omnidirektionalen Spiegeln, die in der Panorama-Empfangseinheit eingesetzt werden können;
• 4 Ausführungsform einer Panorama-Empfangseinheit mit katadioptrischer Empfangsoptik;
• 5 Ausführungsform einer Panorama-Empfangseinheit mit katadioptrischer Empfangsoptik und Empfangslinse;
• 6 schematische Darstellung der Anordnung der Sendeelemente für einen 360°-Scanbereich;
• 7 schematische Darstellung der Anordnung der Sendeelemente für einen 180°-Scanbereich;
• 8 schematische Darstellung der Anordnung der Sendeelemente für einen 360°-Scanbereich, bei dem die Sendelemente kreisförmig gebogen angeordnet sind;
• 9 schematische Darstellung von mehreren, übereinanderliegenden Reihen von Sendeelementen;

The invention will be explained below with regard to further advantages and features with reference to the accompanying figures with reference to embodiments. It shows:

• 1 a schematic view of an optical scanner with transmitting elements and panoramic receiving unit;
• 2 the optical scanner off 1 in a schematic side view;
• 3 Embodiments of omnidirectional mirrors that can be used in the panoramic receiving unit;
• 4 Embodiment of a panoramic receiving unit with catadioptric receiving optics;
• 5 Embodiment of a panoramic receiving unit with catadioptric receiving optics and receiving lens;
• 6 schematic representation of the arrangement of the transmitting elements for a 360 ° scan range;
• 7 schematic representation of the arrangement of the transmitting elements for a 180 ° scanning range;
• 8th schematic representation of the arrangement of the transmitting elements for a 360 ° scan range, in which the transmitting elements are arranged curved in a circle;
• 9 schematic representation of several, superimposed rows of transmitting elements;

In the following figures, identical parts are provided with identical reference numerals.

1 and 2 show schematically the optical scanner according to the invention 1 with at least one transmitting element 2 and at least a panoramic reception unit 10 and receiver 4 and a control and evaluation unit 6 for evaluating the light transit time of the light or of light rays 30 from the transmitting element 2 about an object 32 to the panoramic reception unit 10 and receiver 4 , wherein a plurality of transmitting elements 2 circular section or part-circular in a row in a common housing 8th are arranged, wherein the light is emitted fan-shaped and / or received in different angular directions, wherein the distances of the emitted light beams of the transmitting elements increase with increasing distance to the optical scanner and / or the distances of the received light beams of the panoramic receiving unit 12 Reduce with decreasing distance to the optical scanner.

3 shows examples of omnidirectional mirrors 18 in the panoramic reception unit 10 can be used. In addition to the omnidirectional mirror, lenses and apertures can be used to relay the received light to the receiver.

4 and 5 each show a catadioptric receiving optics. This type of receiving optics consists of a lens with mirrored surfaces. The object 32 reflected light is redirected by this optics to the receiver. To form the receiving light, an aperture 14 and / or lens 16 be used.

6 shows schematically the arrangement of the transmitting elements 2 for a scan area of 360 °. These are arranged in a circle-shaped or part-circular manner in a circle. In front of the transmitting elements 2 are lenses 24 arranged a lens system 28 form. The lenses 24 are according to 6 provided for example for each 8 transmitting elements. The lenses 24 are formed and arranged such that the light beams 30 the transmitting elements 2 fan-shaped with even angular intervals are emitted. But they can also be lenses 24 for every natural number of transmit elements 2 be provided. So, for example, before each transmitting element 2 a lens 24 or a lens system 28 to be ordered. It can also be provided that in front of one, in particular even number of transmitting elements 2 , a lens 24 or a lens system 28 is arranged.

The control and evaluation unit 6 is with all transmitting elements 2 connected and is capable of all transmission elements 2 driving. The transmission elements 2 can be controlled for example via a bus system. It can also be provided that the transmitting elements 2 form a shift register structure.

About the control and evaluation unit 6 become the transmitting elements 2 For example, driven in such a way that they send out successively short light pulses, their duration from the transmission to the reception via the receiver 4 is measured after this from an object 32 were reflected. This can be done by the control and evaluation unit 6 the distance of objects 32 be determined or evaluated in a surveillance area.

In addition to the light transit time measurement, the optical scanner 1 also work according to the principle of phase measurement.

7 shows for a further embodiment of an optical scanner 1 the arrangement of the transmitting elements 2 for a fan-shaped scanning area or monitoring area of about 180 °.

Here are the transmitting elements 2 circular section or part-circular rows as in 6 shown arranged. In this example, each send element is 2 a lens 24 or a lens system 28 assigned.

8th explicitly shows an arrangement in which the transmitting elements 2 are arranged part-circular, circular-segment-shaped or circular curved, each transmitting element 2 is arranged at a slightly different angle. This realization is possible in particular with a thin substrate.

9 schematically shows a further embodiment of an optical scanner with a fan-shaped scanning or monitoring area. Here are the transmitting elements 2 arranged in circular section or part-circular rows arranged.

As a result, a partially cylindrical scanning area or monitoring area can be realized.

The structure according to 9 can also be realized for any fan-shaped scan areas with angles up to 360 °, so that, for example, a cylindrical scan area or monitoring area is formed.

LIST OF REFERENCE NUMBERS

1

optical scanner

2

transmitting element

4

receiving element

6

Control and evaluation unit

8th

casing

10

Panorama reception unit

12

catadioptric appearance

14

cover

16

lens

18

omnidirectional mirror

20

mirrored surface

24

lens

26

microlens

28

lens system

30

beam of light

32

object

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2237063 B1 [0003, 0008]
• EP 2237064 B1 [0003, 0008]
• EP 2910970 B1 [0009]

Claims (13)

Optical scanner having at least one transmitting element (2) and at least one panoramic receiving unit (10) with at least one receiving element (4) and a control and evaluation unit (6) for evaluating the light transit time of light beams from the transmitting element (2) via an object (32 ) to the receiving element (4), wherein a plurality of transmitting elements (2) in a common housing (8) are arranged, the light beams (30) in different angular directions can fan out through a convex surface on an outer side of the housing, characterized in that the fan-shaped receiving beams can be received with a panoramic receiving unit over an angle up to 360 °. Optical scanner after Claim 1 characterized in that the panoramic receiving unit (10) for guiding the light uses rotationally symmetrical reflecting surfaces and / or lenses and / or diaphragms. Optical scanner after Claim 1 or 2 , characterized in that the panoramic receiving unit (10) contains a catadioptric optics (12). Optical scanner according to one of the preceding claims, characterized in that the reflection in the catadioptric optical system (12) is produced by total reflection. Optical scanner according to one of the preceding claims, characterized in that the transmitting elements (2) are arranged in a full circle. Optical scanner according to one of the preceding claims, characterized in that the transmitting elements (2) are arranged on a flexible printed circuit board. Optical scanner according to one of the preceding claims, characterized in that the transmitting elements (2) are arranged in a matrix with at least two rows. Optical scanner according to one of the preceding claims, characterized in that at least one transmitting element (2) is arranged per angular degree. Optical scanner according to one of the preceding claims, characterized in that the transmitting elements (2) are arranged on at least two circles of different diameters and / or not equidistant from the angle. Optical scanner according to one of the preceding claims, characterized in that the transmitting elements (2) are arranged on an at least partially rigid part-circular, circular section-shaped, circular, partially cylindrical, cylindrical, part-spherical, spherical segment-shaped or spherical plastic carrier with integrated circuit boards. Optical scanner according to one of the preceding claims, characterized in that at least one lens (24) and / or a microlens (26) is arranged in front of each transmitting element (2). Optical scanner according to one of the preceding claims, characterized in that the lenses (24) or microlenses (26) form a lens system (28). Optical scanner according to one of the preceding claims, characterized in that the control and evaluation unit (6) has a logic module, in particular of the type CPLD (Complex Programmable Logic Device) or FPGA (Field Programmable Gate Array).

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