WO2023137564A1

WO2023137564A1 - Beam steering system with a configurable beam deflection element

Info

Publication number: WO2023137564A1
Application number: PCT/CA2023/050076
Authority: WO
Inventors: Alexander Greiner; Siegwart Bogatscher; Nico Heussner; Andreas HÖLLDORFER
Original assignee: Leddartech Inc.
Priority date: 2022-01-24
Filing date: 2023-01-24
Publication date: 2023-07-27

Abstract

An apparatus for use in a light detection and ranging (LIDAR) system is provided. The apparatus comprises a transmitting stage configured to generate a light beam; a beam steering element configured to selectively provide a plurality of interaction modes each of which corresponds to a respective beam divergence of a deflected light beam. The beam steering element includes a deflector configured to receive the light beam and to produce the deflected light beam. The deflector includes a plurality of surfaces and is configured to be rotatable with respect to a pivot such that a respective one of the plurality of interaction modes is selectively enabled by positioning a selective surface of the plurality of surfaces to receive the light beam and to reflect the deflected light beam at a corresponding beam divergence. Because the deflector is rotatable to receive incident lights, various divergences the LIDAR system could be achieved.

Description

BEAM STEERING SYSTEM WITH A CONFIGURABLE BEAM DEFLECTION ELEMENT

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims the benefit of U.S. Provisional Application Serial No. 63/302,433, filed on January 24, 2022, hereby incorporated by reference herein.

FIELD OF THE INVENTION

[0002] The invention relates to beam steering system for deflecting a light beam, either visible light or non-visible light. The beam steering system has a moveable beam deflection element configured to acquire a selectable interaction mode with the incident light beam. The invention also relates to a method for steering a light beam and to a method for dynamically controlling the interaction mode between the incident light beam and the beam deflection element. The beam steering system can be used in a light detection and ranging (LIDAR), with a camera or other environment imaging devices.

BACKGROUND OF THE INVENTION

[0003] Beam steering systems, used on the emitter side or on the receiver side of a LIDAR use beam deflection elements to deflect the light beam, either the emitted beam or the received beam. In the case of the emitter side, the beam deflection element is controlled to deflect the beam according to a pattern, which can be predetermined or random, such as to scan a Field of View (FOV).

[0004] A mirror is an example of a beam deflection element. To enable the beam to be steered, the mirror can be mounted on a Micro-Electro-Mechanical system (MEMS) which imparts to the mirror a scanning motion. For example, the MEMS can be configured such as to cause the mirror to oscillate according to a certain frequency that will produce a scanning motion of the incident light beam in the FOV. [0005] A disadvantage of such beam deflection element is the static nature of the interaction between the mirror and the light beam. In this instance, the interaction is a reflection of the light beam on the mirror surface, determined by the physical properties of the mirror surface. That interaction, however, is the same and does not change depending on the operational requirements of the beam steering system. While the reflection of the incident light beam may generate a reflected light beam of suitable attributes for a certain range of operational conditions of the beam steering system, those attributes may not be suitable for all operational conditions.

SUMMARY OF THE INVENTION

[0006] As embodied and broadly described herein, the invention provides a beam steering system comprising a steerable beam deflector configured to deflect an incident light beam, the beam deflector being configured to acquire a selectable interaction mode with the incident beam among a plurality of interaction modes, the steerable beam deflector being configured such as to impart to the deflected beam a property in dependence of the selected mode of interaction. The beam steering system further includes a steerable beam deflector controller configured to dynamically select an interaction mode of the beam deflector among the plurality of interaction modes and output a control signal conveying the selected interaction mode, the beam deflector being responsive to the control signal to acquire the selected interaction mode.

[0007] In a first example of implementation, the property of the deflected light beam is the angle of divergence of the deflected light beam, wherein in a first mode of interaction the angle of divergence is narrower than the angle of divergence in a second mode of interaction.

[0008] In a second example of implementation, the property of the deflected light beam is the wavelength composition of the light beam, wherein in a first mode of interaction the deflected light beam includes wavelengths that are filtered out in a second mode of interaction.

[0009] According to a third aspect, an apparatus for use in a light detection and ranging (LIDAR) system is provided. The apparatus comprises: a transmitting stage configured to generate a light beam; a beam steering element configured to selectively provide a plurality of interaction modes each of which corresponds to a respective beam divergence of a deflected light beam. The beam steering element includes: a deflector configured to receive the light beam and to produce the deflected light beam, wherein the deflector includes a plurality of surfaces and is configured to be rotatable with respect to a pivot such that a respective one of the plurality of interaction modes is selectively enabled by positioning a selective surface of the plurality of surfaces to receive the light beam and to reflect the deflected light beam at a corresponding beam divergence.

[0010] In some specific implementations, the selective surface of the plurality of surfaces includes a mirror, which is configured to reflect the deflected light beam at the corresponding beam divergence that is identical to that of the light beam generated by the transmitter.

[0011] In some specific implementations, the selective surface of the plurality of surfaces includes a convex surface, which is configured to reflect the deflected light beam at the corresponding beam divergence that is greater than that of the light beam generated by the transmitter.

[0012] In some specific implementations, the selective surface of the plurality of surfaces includes a concave surface, which is configured to reflect the deflected light beam at the corresponding beam divergence that is less than that of the light beam generated by the transmitter.

[0013] In some specific implementations, the deflector further comprises a filter that is placed on the selective surface of the plurality of surfaces.

[0014] In some specific implementations, the filter is a bandpass filter configured to filter out bands that fall outside a filter band of the bandpass filter from the deflected light beam.

[0015] In some specific implementations, the selective surface of the plurality of surfaces is a mirror, and the filter is placed on the mirror.

[0016] In some specific implementations, the deflector further comprises a grating that is placed on the selective surface of the plurality of surfaces, the grating being configured to increase the respective beam divergence of the deflected light beam.

[0017] In some specific implementations, the selective surface of the plurality of surfaces is a mirror, and the grating is placed on the mirror. [0018] In some specific implementations, a cardinality of the plurality of surfaces is 2.

[0019] In some specific implementations, a cardinality of the plurality of surfaces is 8.

[0020] In some specific implementations, the apparatus further comprises a beam deflector controller configured to control rotation of the deflector to position the selective surface of the plurality of surfaces to receive the light beam based on an operational profile.

[0021] In some specific implementations, the apparatus further comprises a path planning controller configured to provide an index of the operational profile to the beam deflector controller to control the rotation of the deflector.

[0022] In some specific implementations, the operational profile defines a desired resolution, and the deflector is configured to rotate with respect to the pivot such that the selective surface of the plurality of surfaces is configured to be positioned to reflect the deflected light beam at the corresponding beam divergence that corresponds to the desired resolution.

[0023] In some specific implementations, the operational profile defines a scanning range where objects of interest reside at a distance from the LIDAR system, and the deflector is configured to rotate with respect to the pivot such that the selective surface of the plurality of surfaces is configured to be positioned to reflect the deflected light beam at the corresponding beam divergence that corresponds to the scanning range.

[0024] In some specific implementations, the operational profile defines a desired reflection, and the deflector is configured to rotate with respect to the pivot such that the selective surface of the plurality of surfaces is configured to be positioned to reflect the deflected light beam at the corresponding beam divergence that corresponds to the desired reflection.

[0025] In some specific implementations, the apparatus further comprises collimating optics coupled to the transmitting stage, the collimating optics being configured to focus the light beam.

[0026] In some specific implementations, the light beam is highly polarized. [0027] In some specific implementations, the apparatus further comprises a receiving stage configured to sense light returns, and a beam splitter configured to separate the light beam from the light returns.

[0028] In some specific implementations, the apparatus further comprises a stepper motor for driving rotation of the deflector.

[0029] According to a fourth aspect, a computer-implemented method of configuring an apparatus that is used in a light detection and ranging (LIDAR) system is provided. The apparatus comprises a beam steering element. The method comprises: deriving a desired operational profile of the LIDAR system, wherein the desired operational profile defines an interaction mode of the beam steering element; and controlling a surface of a deflector of the beam steering element to be positioned to receive a light beam such that the interaction mode of the beam steering element is enabled to generate a deflected light beam at a desired beam divergence that is indicated in the desired operational profile.

[0030] In some specific implementations, the method further comprises: receiving an operational condition request that specifies the desired operational profile of the LIDAR system; consulting a library that maps a plurality of operational profiles to respective sets of operational settings of the LIDAR system; and obtaining a set of operational settings that corresponds to the desired operational profile.

[0031] In some specific implementations, controlling a surface of a deflector of the beam steering element to be positioned to receive a light beam comprising: based on the obtained set of operational settings that correspond to the interaction mode, rotating the deflector to enable the surface of the deflector to be positioned to receive the light beam such that the interaction mode is activated.

[0032] In some specific implementations, the desired operational profile includes an operational profile for identifying objects of interest in an area part of a scene.

[0033] In some specific implementations, the desired operational profile includes an operational profile for long-range scanning a distance from the LIDAR system where objects of interest reside. [0034] In some specific implementations, the desired operational profile includes an operational profile for short-range scanning a distance from the LIDAR system where objects of interest reside.

[0035] In some specific implementations, the desired operational profile includes an operational profile for scanning objects that generates a desired reflection.

[0036] In some specific implementations, the desired operational profile includes a desired resolution and a subset of tiles in a field of view (FOV) in a desired area.

[0037] In some specific implementations, the operational condition request is received by: determining that the LIDAR system is used in an autonomous or semi-autonomous automotive mode; implementing path planning to issue that operational condition request that enable the autonomous or semi-autonomous automotive mode.

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a block diagram illustrating components of a LIDAR apparatus using a beamsteering system.

[0039] Figure 2 is a more detailed block diagram of the receiving and transmitting stages of the LIDAR apparatus shown in Figure 1.

[0040] Figure 3 is an arrangement which is a variant of the arrangement shown in Figure 2.

[0041] Figure 4A is a diagram of the first steering stage of the LIDAR apparatus shown in Figure 1, set in a first mode of interaction with the incident light beam.

[0042] Figure 4B is a diagram of the first steering stage of the LIDAR apparatus shown in Figure 1, set in a second mode of interaction with the incident light beam. [0043] Figure 4C is a diagram of the first steering stage of the LIDAR apparatus shown in Figure 1, set in a third mode of interaction with the incident light beam.

[0044] Figure 5 is a diagram of the first steering stage according to a variant.

[0045] Figure 6 is a block diagram of a controller of the LIDAR apparatus shown in Figure 1, allowing to selectively set the interaction mode of the light beam deflection element.

[0046] Figure 7 is an illustration depicting a field of view of the LIDAR apparatus of Figure 1 divided onto selectable tiles.

[0047] Figure 8 is a flowchart of a process implemented by the controller shown in Figure 6.

[0048] Figure 9 illustrates a look up table which maps a respective sequence of tiles to a corresponding operational setting.

DESCRIPTION OF AN EXAMPLE OF IMPLEMENTATION

[0049] With reference to Figure 1, a LIDAR apparatus 10 is shown which creates a point cloud depicting the scene or environment 26. The LIDAR apparatus includes a transmitting stage 14, which includes a light source to illuminate the scene 26. Objects in the scene 26 will reflect or back scatter the projected light. The light returns are sensed by the receiving stage 12, where they are converted into electrical signals. The light returns convey distance information from objects in the scene 26 which can be measured on the basis of Time Of Flight (TOF) and Frequency- Modulated Continuous-Wave (FMCW), among others. A controller 68 shown in Figure 6 converts the electrical signals into a point cloud which is a set of data points in space that represent a 3D shape of the scene. Typically, but not always, each data point has a set of X, Y and Z coordinates. [0050] The LIDAR apparatus 10 has a beam-steering system 28, which is also referred to as “beam-steering engine”. The beam-steering engine 28 can include a single or multiple beamsteering stages. When used on a vehicle, the LIDAR apparatus 10 can be placed either at the back or front of a host vehicle to create a representation of the environment in which the vehicle travels. The vehicle can be a terrestrial vehicle, an aerial vehicle or a maritime vehicle. In the example shown, the beam-steering engine 28 has two beam-steering stages 20 and 22, respectively. Each beam-steering stage is designed to deflect the light beam by a certain angle. The angular deflections produced at each stage add up (or subtract) to produce an outgoing beam that is directed at the scene 26. By altering the deflection angles at the beam-steering stages 20 and 22, it is possible to impart to the outgoing beam a scanning motion and thus scan the scene in a larger FOV.

[0051] Generally speaking, multiple beam-steering stages are useful because they can increase the overall angular beam deflection range at the output of the LIDAR apparatus 10.

[0052] The beam-steering stages 20, 22 can operate on the basis the same or different beamsteering technologies. For example, the first beam-steering stage 20 includes a moveable lightbeam deflection element, which will be described further below. The deflection element is designed to deflect, such as by reflection or diffraction the incoming beam and by changing the position or orientation of the deflection element the properties of the outgoing beam change, such as the angle of propagation of the beam. In a specific example, the deflection element can be a Micro-Electro-Mechanical System (MEMS) using a moveable mirror to deflect the incoming beam and produce a scanning pattern of light. The moveable mirror disclosed herein means that the mirror is rotatable with respect to a pivot such that the first beam-steering stage could achieve a scanning motion. The MEMS mirror is controlled by a scanning mechanism that imparts to the mirror a cyclical movement producing a repeating scan of the outgoing beam. The scan can walk the beam in the horizontal direction, the vertical direction or have a hybrid pattern, such as for example a raster pattern. Typically, the movement of a MEMS mirror is a continuous movement over a predetermined angular steering range such as to produce a continuous displacement of the beam into the scene. [0053] In a specific example, the second beam-steering stage 22 is a solid-state beam-steering stage using optical elements to selectively impart to the light beam a propagation direction that defines a non-zero angle with relation to the direction of incidence of the incoming beam. In this example, the beam steering stage 22 operates such that the beam is steered without any mechanical motion of the optical component performing the beam steering. In a specific example of implementation, the second stage 22 uses a static grating with a director pattern that interacts with the incoming light to diffract the light in a direction of propagation that is determined by the director pattern properties.

[0054] With specific reference now to Figure 2 the transmitting and the receiving stages 12 and 14 will be described in greater detail. The transmitting stage 14 has a laser source 30 that can operate in the 900 nm range or alternatively in the 1500 nm range. In another example, the laser source 30 can be configured to generate visible light, such as through interaction (not shown in the drawings) with material, such as phosphor, that receives the laser light and generates, in response to the laser excitation, a light output over a broader and visible wavelength range.

[0055] The outgoing laser beam is focused by collimating optics 32 toward an optical path that is shared by the transmitting stage 14 and the receiving stage 12, including a beam splitter 38 which separates the outgoing beam from the optical returns. In the case of the incoming beam received from the collimating optics 32, the laser light is highly polarized such that most of the energy is reflected by the beam splitter, which can be a polarization beam splitter toward the beam-steering engine 28 over the optical path 16. As to reflected or back-scattered light collected from the scene 26 and which is transmitted through the steering engine 28, the light is transmitted back over the optical path toward the beam splitter 38. However, since this light has lost a significant degree of polarization, the bulk of the energy is transmitted through the beam splitter 38 toward the receiving stage 12.

[0056] This shared optical path configuration has advantages in terms of simplicity and compactness, at the expense of some optical losses. [0057] The returning optical light from the beam splitter 38 is received by an objective 36 which focuses the light on the sensitive surface of an optical receiver 34. The receiver 34 may be one using Avalanche Photo Diodes (APDs). While not shown in the drawings the electrical output of the receiver 34 is directed at the controller that generates the point cloud. The controller also controls the operation of the transmitting stage 14 and the operation of the beam-steering engine 28 such as to synchronize all these components.

[0058] Figure 3 illustrates a variant of the architecture shown in Figure 2, in which the transmitting and the receiving optical paths are separated and independent from each other. In this example, the LIDAR apparatus 10 has a transmitter 26 with a transmitting stage using a dedicated steering engine 28 and a receiver 42 using its own steering engine 28. Physically, both the receiver 42 and the transmitter 26 are placed in a housing side by side, either vertically or horizontally. It is to be noted that the transmitting steering engine and the receiving steering engine are controlled independently from each other. While in most situations their operations would be synchronized it is possible, they are not always synchronized.

[0059] Figure 4A illustrates in greater detail the structure of the first steering stage 20. The first steering stage 20 includes a light-beam deflection element 44 that receives the incident light beam 46 and deflects it to produce a deflected light beam 48 that propagates at an angle relative to the incident light beam. In this example the angle is about 90 degrees. The deflection is produced by the interaction between the incident light beam 46 and the deflection element 44.

[0060] The deflection element 44 is configured to provide multiple interaction modes with the incident light beam to be able to adapt the deflected light beam 48 according to the operational requirements of the LIDAR. The examples of implementation shown in Figures 4A-C achieve the multiple interaction modes by providing the deflection element 44 with multiple interaction surfaces, which are selectively activated depending on the desired interaction mode. For instance, the deflection element 44 has two opposed surfaces 50 and 52, which can be selectively positioned to face the incident light beam 46 and thus interact with the incident light beam 46. The deflection element 44 is mounted on a pivot or swing axis allowing the deflection element to move angularly along the arrow 54, clockwise or counterclockwise. That is, the deflection element 44 is rotatable to enable each of the two opposed surfaces 50 and 52 to be selectively positioned to receive the incident light beam 46. Such arrangement can include a stepper motor for driving the deflection element 44 about the pivot axis allowing to position the deflection element 44 at any selected angular orientation and to move the deflection element back and forth over a selected angular range. Other mechanical systems can also be used, such as combination of stepper motor and MEMS, where the stepper motor positions the deflection element 44 in the desired interaction mode, in other words orient the desired surface of the deflection element 44 toward the light beam 46, while the MEMS arrangement causes the deflection element to oscillate over a certain angular range to provide the beam steering function.

[0061] In a first mode of interaction shown in Figure 4 A, in which the deflection element 44 is rotated such that the surface 50 is oriented towards the incident light beam 50 and thus interacts with it, the surface 50 includes a mirror that reflects the incident light beam 46 and preserves the angle of divergence of the incident light beam 46. In this mode of interaction, the angle of divergence of the deflected light beam 48 is generally similar to the angle of divergence of the incident light beam 46.

[0062] In a second mode of interaction shown in Figure 4B, the deflection element 44 is continuously rotated such that the surface 52 is oriented towards the incident light beam 46 and interacts with the incident light beam 46. This mode of interaction is achieved by operating the stepper motor to turn the deflection element 44 to rotate over 180 degrees and thus expose the surface 52. The surface 52 is provided with a treatment which provides a different interaction with the incident light beam 46, when compared to the mirror 50. The surface treatment on the surface 52 changes the angle of divergence of the incident light beam 46, increasing the angle of divergence to generate a deflected light beam 48 that diverges at an increased rate. An example of a surface treatment includes a surface that is slightly convex to produce the desired beam divergence. Alternatively, by making the surface concave, the opposite effect will be achieved, which is to obtain a converging light beam.

[0063] In a third example of interaction shown in Figure 4C, the surface of the deflection element 44 is provided with a filter to change the wavelength spectrum of the incident light beam 46. For instance, the filter can be a bandpass filter or another filter. In the case of a bandpass filter, wavelengths that fall outside the filter band are strongly attenuated and will thus be removed from the deflected light beam 48. In terms of implementation, the third mode of interaction can be achieved by placing the optical structure implementing the bandpass filter, which preferably is lamellar, over the mirror surface 50 such that incident light 46 makes a first pass through the bandpass filter, is reflected by the mirror and then makes a second pass through the bandpass filter and then exits the beam steering engine 28. It is noted that although the filter is provided with the surface 52 in the example of FIG. 4C, this is illustrative and not intended to be limiting. In other examples, the filter could be provided to the surface 50 as well. In case the deflection element 44 has more than two surfaces, a respective filter could be provided to each surface of the deflection element 44 or placed at any surface of the deflection element 44.

[0064] In a fourth example of interaction, the surface of the deflection element 44 is provided with a grating operating to increase the deflection angle of the light beam as in Figure 4D. It should be appreciated that although the grating operating is provided with the surface 52 in the example of FIG. 4D, this is illustrative and not intended to be limiting. In other examples, the filter could be provided to the surface 50 as well. In case the deflection element 44 has more than two surfaces, a respective grating operating could be provided to each surface of the deflection element 44 or placed at any surface of the deflection element 44.

[0065] Once the deflection element is set in the desired mode of interaction, by operating the stepper motor or any other positioning arrangement, the beam deflection element is subjected to cyclical motion such as to repeatedly walk the deflected light beam through the FOV 26. The range of angular motion of the deflection element can vary depending on the desired FOV. The range of motion can be fixed for each mode of interaction or can vary from one mode of interaction to another. Also, the range of angular motion can dynamically change within a given mode of interaction.

[0066] Figure 5 illustrates a variant in which the deflection element has n surfaces corresponding to n different interaction modes. [0067] The control of the LIDAR apparatus 10 in general and the operation of the various steering stages in particular is controlled by a controller 68. A block diagram of the controller 68 is shown in Figure 6. The controller has a processing engine 70 which includes one or more CPUs executing software in the form of machine instructions encoded on a non-transitory machine-readable medium. The instructions define the overall functionality of the processing engine 70.

[0068] The controller 68 has an input interface 72 that receives inputs from external entities. These inputs are in the form of signals which the processing engine 70 processes and generates outputs via the output interface 74. The outputs would typically be control signals to drive components of the LIDAR apparatus 10. Also, the output interface 74 outputs the point cloud sensed by the LIDAR apparatus 10 and which is the 3D representation of the scene.

[0069] A library stores multiple LIDAR operational profiles 78. A LIDAR operational profile 78 is a configuration setting that conveys a number of parameters of the LIDAR apparatus 10 that can be varied to tailor the operation of the LIDAR apparatus 10 to a range of different operational conditions. In a first example, the LIDAR apparatus 10 can be adjusted such as to focus the sensing in one area of the scene at the expense of other areas of the scene. This would be the case in instances where objects of interest are identified in some portion of the scene, and it would be desirable to focus the LIDAR apparatus in that area to get a more complete scan on the objects of interest. In such case, the surface 50 of the deflector 44 may be positioned to receive the incident light beams to achieve a more complete scan on the objects of interest in a specific area of the scene. In other examples, a concave surface of the deflector 44 may be positioned to receive the incident light beams. In a second example, the LIDAR operational profile 78 specifies settings configuring the scanning beam for a longer-range scanning where objects of interest reside at a longer distance from the LIDAR apparatus 10. For example, the longer-range scanning defines a scanning of a distance no less than 100 meters. In that case, the less divergence of the deflected beam is desired. Thus, the surface 50 with a mirror or a concave surface may be positioned to receive the incident light beams to reduce the divergence of the deflected beam. In a third example, the LIDAR operational profile 78 specifies settings configuring the scanning beam for a shorter- range scanning where objects of interest reside at a shorter distance from the LIDAR apparatus 10, and/or for objects that generate strong reflections, such as road signs. The shorter-range scanning defines scanning of a distance less than 100 meters. In that case, the more divergence of the deflected beam is desired. Thus, the convex surface 52 of the deflector may be positioned to receive the incident light beams to increase the divergence of the deflected beam such that eye safety is improved in the shorter-range scanning. In the case where the objects generate strong reflection, positioning the convex surface 52 to receive the incident light beams and to deflect to the objects may help to increase the divergence of the deflected beam and improve the eye safety significantly. In some cases, in order to maximize the divergence, the grating element may be attached to the convex surface 52 to receive the incident light beam. Thus, the divergence of the reflected light beam may be further increased.

[0070] It should be appreciated that the shorter-range scanning and longer-range scanning are relative terms. In this example, a distance of scanning less than 100 meters is defined as shorter- range scanning. In other examples, a distance of scanning less than a pre-configured value may be defined as shorter-rang scanning while a distance of scanning greater than or equal to the preconfigured value may be defined as longer-rang scanning.

[0071] In a specific mode of implementation, the LIDAR operational profile 78 conveys the following controllable parameters of the LIDAR apparatus 10:

1. Intensity of the light beam generated by the laser source 30. For example, the profile can specify a setting among N possible power settings (N is an integer no less than 1).

2. Area of the scene that is to be scanned. This setting can be characterized in numerous ways. One possibility is to define a window in the overall field of view in which the light beam is to be directed. In a specific example, the field of view (FOV) can be divided in a plurality of virtual tiles and the setting can specify which tile or set of tiles are to be scanned. Figure 7 illustrates an example of a field of view (FOV) divided in tiles, the arrangement being such that there are four rows of eight tiles each, for a total of thirty -two tiles. The setting can specify a subset of tiles that are to be scanned. For instance, the setting may convey the coordinates of the selected sub-set of tiles, such that the optical beam excursions will be restricted to the requested sub-set of tiles. In the example shown, the highlighted set of four tiles is stated in the profile and the optical beam will be controlled such that it scans the area defined by the four tiles only. Note, the set of tiles do not need to be contiguous. Once the definition of the tiles is provided to the controller 68, the logic of the controller can determine the operational setting of the steering engine in order to obtain the desired beam scan. The desired mode of interaction between the light beam and the deflection element. Note, the desired mode of interaction may be implied when specifying a certain ranging property of the LIDAR, such as ranging distance. For longer ranging distances, the mode of interaction where the beam divergence is kept to a minimum, is implicit. For shorter ranging distances, a different mode of interaction, where the degree of beam divergence is greater, is implied. The desired mode of interaction mode means which surface of the deflection element is desired to be positioned to receive the incident light to achieve a desired divergence. The LIDAR operational profile 78 can specify more or less resolution in certain areas, whether in the X and Y plane or in the X, Y and Z space and let the controller 68 determine the actual LIDAR apparatus 10 settings to achieve the desired resolution in the desired area. Assuming the field of view (FOV) is characterized as a series of tiles, the setting can provide an indication of the subset of tiles and the degree of resolution that is desired. The controller 68 would automatically set the various parameters of the LIDAR apparatus 10 such as the beam intensity and steering engine operation parameters, among others. Since the resolution parameter is function of the beam divergence, a specified resolution of the LIDAR would also imply a particular mode of interaction between the light beam and the deflection element. That is to say, a higher resolution would imply using a mode of interaction where the light beam divergence is kept to a minimum, while a lower resolution would imply using a mode of interaction where a greater light beam divergence is acceptable. A resolution is a system characteristic that is used to evaluate how many pixels or details are mapped on an object per foot or meter. In some examples, a higher resolution defines a 1 -milliradian (mrad) resolution whereas a lower resolution defines a 5-mrad resolution. A higher resolution corresponds to a finer “grid” in the X-Y plane at a specific distance. Thus, higher resolution would provide more details of objects whereas lower resolution would provide less details of objects. In the case of the higher resolution, the divergence of the deflected light beam may be minimized by positioning the flat surface 50 or positioning a concave surface to receive the incident light beam. In the case of the lower resolution, the divergence of the deflected light beam may be maximized by positioning the convex surface 52 to receive the incident light beam. In some examples, in order to further reduce the divergence, a grating element may be stacked on the convex surface 52 of the deflector 44, based on a specific lower resolution. It should be appreciated that the higher resolution and lower resolution are relative terms. Although an example 1- mrad resolution is illustrated as higher resolution and an example 5-mrad resolution is illustrated as lower resolution, this is only illustrative and is not intended to be limiting. In other examples, different respective suitable values may be set for the higher resolutions and lower resolutions.

[0072] In a specific example of implementation, the input 78 may therefore only convey an index in the library of operational profiles such that the controller 68, upon receipt of the index can identify the requested profile, read the settings in that profile and adjust the operation of the LIDAR apparatus 10 accordingly, including the interaction mode of the deflection element among other properties of the beam steering engine 28. The controller 68 switches between profiles as requested, as the index changes. The index can be supplied by a path planning controller, when the LIDAR apparatus 10 is used in autonomous or semi-autonomous automotive applications. That is to say, the planning path controller determines which LIDAR operational mode is best suited for path planning purposes and issues a request to that effect, which is the index in the library of profiles. That is, based on a specific path planning purpose and corresponding LIDAR operational mode, operational parameters included in an operational condition request may be set to implement the autonomous or semi-autonomous automotive applications. For example, a short- range scanning is needed to scan pedestrians in pedestrian crossings in autonomous automotive applications. In that case, the convex surface 52 of the deflector 44, such as shown in FIG. 4B, may be positioned to receive the incident light beams to increase the divergence of the deflected beam such that eye safety is improved in the shorter-range scanning. Alternatively, a grating element may be placed on the convex surface 52 of the deflector 44 to further increase the divergence of the deflect light beam.

[0073] The LIDAR receiving stage output 80 also feeds into the controller 68 which reads the output of the APDs 34, applies algorithms to detect distances for various points in the scene and generates a point cloud, which is a 3D representation of the scene. Optionally, the controller 68 can perform detection in the point cloud to identify features associated with objects. The detected objects and the point cloud are output at 88 through the output interface 74. The point cloud is output as a succession of data frames.

[0074] The output interface 74 releases the point cloud at 88 and optionally detected objects information. In addition, it releases control signals 82 to control the laser source 30 at the LIDAR transmitting stage 14 and control signals 86 to operate the beam steering engine 28. The control signals are derived from the operational settings. More specifically, the control signals 86 to operate the beam steering engine 28 include:

1. Selection of the interaction mode among the range of interaction modes that the beam steering engine 28 provides,

2. Control of the oscillatory motion of the deflection element once the interaction mode has been selected. The oscillatory control of the deflection element includes the frequency of the oscillation, the angular range of the oscillation motion (scan angle) and the direction of the median of the scan angle,

[0075] Figure 8 is a flowchart of the operation of the controller 68. The process starts at 90. At step 92 the controller 68 reads the requested LIDAR operational profile from the library.

[0076] At step 100 the controller 68 determines the operational settings of the beam steering engine of the LIDAR apparatus 10 on the basis of the requested operational profile and implements those settings by issuing control signals to the beam steering engine 28. [0077] In a specific mode of operation, the operational settings are determined in part by the active tiles specified in the operational profile 78 of the LIDAR apparatus 10. That is to say, a particular sub-set of tiles is mapped to a corresponding set of operational settings such that the beam steering engine 28 will restrict the light beam motion to the desired (active) tiles only, by controlling the range of oscillatory motion of the deflection element, for example. The correspondence between the active tiles and the operational settings can be encoded in a look-up table. The entry in the table is the combination of active tiles and the table outputs the operational settings. Figure 9 illustrates a look up table 900 which maps a respective sequence of tiles to a corresponding operational setting.

[0078] As shown in Figure 9, the table holds the list of all the possible sequences 902, 904, 906 of active tiles that may exist in a profile. The first column in the table shows three exemplary sequences 902, 904, 906, where each sequence identifies active tiles in the grid of the field of view (FOV) and corresponds to a specific area of the field of view (FOV) to be scanned. For each sequence of active tiles, a set of corresponding operational settings are determined. For example, operational settings #1 corresponds to a pattern 902 with 4 active tiles, operational setting #2 corresponds to a pattern 904 with 12 active tiles as shown in Figure 9, and operational setting #3 corresponds to a pattern 906 with 16 active tiles as shown in Figure 9. In particular, when a particular set of operational settings is determined, such as by an operational profile, the corresponding sequence of tiles of the FOV are set. Furthermore, the particular set of operational settings defines a plurality of operational parameters of the beam steering engine.

[0079] In some examples, a typical set of operational settings to define the operational parameters of the beam steering engine includes:

1. The range of angular motion of the deflection element (scan angle),

2. Scan frequency,

3. The interaction mode of the deflection element,

4. The direction of the median of the scan angle,

5. Intensity of the light beam, among others [0080] Based on the operational parameters indicated by the typical set of operational settings, the controller 68 derives the interaction mode of the deflection element, such as the deflection element 44. The interaction mode indicates which surface of the deflection element 44 is positioned to face the incident light and to receive the incident light.

[0081] Although the present disclosure describes methods and processes with steps in a certain order, one or more steps of the methods and processes may be omitted or altered as appropriate. One or more steps may take place in an order other than that in which they are described, as appropriate.

[0082] In some embodiments, any feature of any embodiment described herein may be used in combination with any feature of any other embodiment described herein.

[0083] Certain additional elements that may be needed for operation of certain embodiments have not been described or illustrated as they are assumed to be within the purview of those of ordinary skill in the art. Moreover, certain embodiments may be free of, may lack and/or may function without any element that is not specifically disclosed herein.

[0084] It will be understood by those of skill in the art that throughout the present specification, the term “a” used before a term encompasses embodiments containing one or more to what the term refers. It will also be understood by those of skill in the art that throughout the present specification, the term “comprising”, which is synonymous with “including,” “containing,” or “characterized by,” is inclusive or open-ended and does not exclude additional, un-recited elements or method steps. As used in the present disclosure, the terms “around”, “about” or “approximately” shall generally mean within the error margin generally accepted in the art. Hence, numerical quantities given herein generally include such error margin such that the terms “around”, “about” or “approximately” can be inferred if not expressly stated.

[0085] In describing embodiments, specific terminology has been resorted to for the sake of description, but this is not intended to be limited to the specific terms so selected, and it is understood that each specific term comprises all equivalents. In case of any discrepancy, inconsistency, or other difference between terms used herein and terms used in any document incorporated by reference herein, meanings of the terms used herein are to prevail and be used.

[0086] Although the present disclosure is described, at least in part, in terms of methods, a person of ordinary skill in the art will understand that the present disclosure is also directed to the various components for performing at least some of the aspects and features of the described methods, be it by way of hardware components, software or any combination of the two. Accordingly, certain technical solutions of the present disclosure may be embodied in the form of a software product. A suitable software product may be stored in a pre-recorded storage device or other similar nonvolatile or non-transitory computer readable medium, for example. The software product includes instructions tangibly stored thereon that enable a processing device (e.g., a microprocessor) to execute examples of the methods disclosed herein.

[0087] The present disclosure may be embodied in other specific forms without departing from the subject matter of the claims. The described example embodiments are to be considered in all respects as being only illustrative and not restrictive. Selected features from one or more of the above-described embodiments may be combined to create alternative embodiments not explicitly described, features suitable for such combinations being understood within the scope of this disclosure.

[0088] Although the systems, devices and processes disclosed and shown herein may comprise a specific number of elements/components, the systems, devices and assemblies could be modified to include additional or fewer of such elements/components. For example, although any of the elements/components disclosed may be referenced as being singular, the embodiments disclosed herein could be modified to include a plurality of such elements/components. The subject matter described herein intends to cover and embrace all suitable changes in technology.

[0089] Although various embodiments of the disclosure have been described and illustrated, it will be apparent to those skilled in the art in light of the present description that numerous modifications and variations can be made. The scope of the invention is defined more particularly in the appended claims.

Claims

CLAIMS:

1. An apparatus for use in a light detection and ranging (LIDAR) system, the apparatus comprising: a transmitting stage configured to generate a light beam; a beam steering element configured to selectively provide a plurality of interaction modes each of which corresponds to a respective beam divergence of a deflected light beam; the beam steering element including: a deflector configured to receive the light beam and to produce the deflected light beam, wherein the deflector includes a plurality of surfaces and is configured to be rotatable with respect to a pivot such that a respective one of the plurality of interaction modes is selectively enabled by positioning a selective surface of the plurality of surfaces to receive the light beam and to reflect the deflected light beam at a corresponding beam divergence.

2. The apparatus of claim 1, wherein the selective surface of the plurality of surfaces includes a mirror, which is configured to reflect the deflected light beam at the corresponding beam divergence that is identical to that of the light beam generated by the transmitter.

3. The apparatus of claim 1, wherein the selective surface of the plurality of surfaces includes a convex surface, which is configured to reflect the deflected light beam at the corresponding beam divergence that is greater than that of the light beam generated by the transmitter.

4. The apparatus of claim 1, wherein the selective surface of the plurality of surfaces includes a concave surface, which is configured to reflect the deflected light beam at the corresponding beam divergence that is less than that of the light beam generated by the transmitter.

5. The apparatus of claim 1, wherein the deflector further comprises a filter that is placed on the selective surface of the plurality of surfaces.

6. The apparatus of claim 5, wherein the filter is a bandpass filter configured to filter out bands that fall outside a filter band of the bandpass filter from the deflected light beam. The apparatus of claim 5, wherein the selective surface of the plurality of surfaces is a mirror, and the filter is placed on the mirror. The apparatus of claim 1, wherein the deflector further comprises a grating that is placed on the selective surface of the plurality of surfaces, the grating being configured to increase the respective beam divergence of the deflected light beam. The apparatus of claim 8, wherein the selective surface of the plurality of surfaces is a mirror, and the grating is placed on the mirror. The apparatus of claim 1, wherein a cardinality of the plurality of surfaces is 2. The apparatus of claim 1, wherein a cardinality of the plurality of surfaces is 8. The apparatus of claim 1, further comprising a beam deflector controller configured to control rotation of the deflector to position the selective surface of the plurality of surfaces to receive the light beam based on an operational profile. The apparatus of claim 12, further comprising a path planning controller configured to provide an index of the operational profile to the beam deflector controller to control the rotation of the deflector. The apparatus of claim 13, wherein the operational profile defines a desired resolution, and the deflector is configured to rotate with respect to the pivot such that the selective surface of the plurality of surfaces is configured to be positioned to reflect the deflected light beam at the corresponding beam divergence that corresponds to the desired resolution. The apparatus of claim 13, wherein the operational profile defines a scanning range where objects of interest reside at a distance from the LIDAR system, and the deflector is configured to rotate with respect to the pivot such that the selective surface of the plurality of surfaces is configured to be positioned to reflect the deflected light beam at the corresponding beam divergence that corresponds to the scanning range. The apparatus of claim 13, wherein the operational profile defines a desired reflection, and the deflector is configured to rotate with respect to the pivot such that the selective surface of the plurality of surfaces is configured to be positioned to reflect the deflected light beam at the corresponding beam divergence that corresponds to the desired reflection. The apparatus of claim 1, further comprising collimating optics coupled to the transmitting stage, the collimating optics being configured to focus the light beam. The apparatus of claim 1, wherein the light beam is highly polarized. The apparatus of claim 1, further comprising a receiving stage configured to sense light returns, and a beam splitter configured to separate the light beam from the light returns. The apparatus of claim 1, further comprising a stepper motor for driving rotation of the deflector. A computer-implemented method of configuring an apparatus that is used in a light detection and ranging (LIDAR) system, wherein the apparatus comprises a beam steering element, the method comprising: deriving a desired operational profile of the LIDAR system, wherein the desired operational profile defines an interaction mode of the beam steering element; and controlling a surface of a deflector of the beam steering element to be positioned to receive a light beam such that the interaction mode of the beam steering element is enabled to generate a deflected light beam at a desired beam divergence that is indicated in the desired operational profile. The method of claim 21, further comprising: receiving an operational condition request that specifies the desired operational profile of the LIDAR system; consulting a library that maps a plurality of operational profiles to respective sets of operational settings of the LIDAR system; and obtaining a set of operational settings that corresponds to the desired operational profile. The method of claim 22, wherein controlling a surface of a deflector of the beam steering element to be positioned to receive a light beam comprising: based on the obtained set of operational settings that correspond to the interaction mode, rotating the deflector to enable the surface of the deflector to be positioned to receive the light beam such that the interaction mode is activated. The method of claim 22, wherein the desired operational profile includes an operational profile for identifying objects of interest in an area part of a scene. The method of claim 22, wherein the desired operational profile includes an operational profile for long-range scanning a distance from the LIDAR system where objects of interest reside. The method of claim 22, wherein the desired operational profile includes an operational profile for short-range scanning a distance from the LIDAR system where objects of interest reside. The method of claim 22, wherein the desired operational profile includes an operational profile for scanning objects that generates a desired reflection. The method of claim 22, wherein the desired operational profile includes a desired resolution and a subset of tiles in a field of view (FOV) in a desired area. The method of claim 22, wherein the operational condition request is received by: determining that the LIDAR system is used in an autonomous or semi-autonomous automotive mode; implementing path planning to issue that operational condition request that enable the autonomous or semi-autonomous automotive mode.