Scanning Laser Device and Method Having Non-Uniform Optical Expansion and Pulse Energy Variation

Abstract

The embodiments described herein provide systems and methods that can improve the performance of a scanning laser device (100). Specifically, the systems and methods utilize a non-uniform variation in optical expansion combined with a variation in the energy level of the laser light pulses to provide an improved effective range across a scan area. In general, the improved effective range varies across a scan field (114), with some areas of the scan field having a relatively long effective range and other areas of the scan field having a relatively short effective range. This varying range across the scan field is facilitated by the expansion optics (108) providing a non-uniform variation in the optical expansion of the laser light pulses with respect to position along a first axis of the scan field, and a light source controller that varies the energy level of the laser light pulses depending on the position along the first axis of the scan field.

Description

Background Art

[0001] Scanning laser devices have been developed and implemented for a wide variety of applications including object detection. For example, optical detection and ranging (LiDAR) systems have been developed to generate 3D maps of surfaces, where the 3D maps describe variations in depth on the surface. Such object detection and depth mapping are used in various applications including detection of objects and motion, navigation, and control. For example, such LiDAR devices are used for navigation and control of autonomous vehicles including autonomous devices used in transportation and manufacturing.

[0002] One problem in some LiDAR systems is the need to balance effective range and power consumption. For example, some LiDAR systems require a relatively long effective range but also need to reduce overall power consumption. Additionally, in some LiDAR systems, different effective ranges are required over different areas, and again, there is a need to reduce overall power consumption. Therefore, improved systems and methods for detection in LiDAR systems and other scanning laser devices are still needed.

Brief Description of the Drawings

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Mode for Carrying Out the Invention

[0021] The embodiments described in this specification provide a system and method that can promote an improved effective range while reducing power consumption in a scanning laser device. Specifically, the system and method utilize non-uniform variations in optical expansion combined with fluctuations in the energy level of laser light pulses to provide an improved effective range across the scanning area while reducing overall power consumption.

[0022] Generally, the improved effective range varies across the scanning field of view, with a relatively long effective range in some areas of the scanning field of view and a relatively short effective range in other areas of the scanning field of view. This variable range across the scanning field of view is facilitated by an expansion optical system that provides non-uniform variation in the optical expansion of the laser light pulse with respect to the position along the first axis of the scanning field of view, and a light source controller that varies the energy level of the laser light pulse in accordance with the position along the first axis of the scanning field of view. Together, the expansion optical system and the light source controller provide this improved effective range while reducing overall power consumption. In a particular embodiment, this improved effective range includes a range that varies across the scanning field of view, including a longer effective range in the central area of the scanning field of view and a shorter effective range in one or more side areas of the scanning field of view. As will be described in more detail below, this variable range can provide improved functionality in some scanning laser device applications.

[0023] Referring now to FIG. 1, a schematic diagram of a scanning laser device 100 is shown. In one embodiment, the scanning laser device 100 is a light detection and ranging (LiDAR) system used for object detection and / or 3D map generation. The scanning laser device 100 includes a light source controller 101, a laser light source 102, an optical assembly 104, and a detector 106. The optical assembly 104 includes various optical elements for laser scanning, including an expansion optical system 108 and a scanning optical system 110. During operation, the laser light source 102 generates pulses of laser light that are scanned by the optical assembly 104 in a pattern 112 of scan lines within the scanning field of view 114.

[0024] The detector 106 is configured to receive reflections of the laser light pulses from objects within the scanning field of view 114. The received reflections of the laser light pulses can then be used to detect these objects within the scanning field of view 114. For example, time-of-flight (TOF) measurements of the received reflections can be used to generate a three-dimensional point cloud that describes the depth of the surface at each point, and thus can be used to generate a depth map of the object surface.

[0025] In the example of FIG. 1, the pattern 112 of the scanning lines within the scanning field 114 includes a raster pattern. However, this is only an example, and in other embodiments, other patterns of the scanning lines used may be generated. To facilitate the generation of the pattern 112, a drive circuit for controlling the movement of the scanning optical system 110 may be implemented. This example will be described in more detail below.

[0026] According to the embodiments described herein, the expansion optical system 108 is configured to provide a non-uniform variation in the optical expansion of the laser light pulse with respect to positions along a first axis within the scanning field 114. The light source controller 101 is configured to vary the energy level of the laser light pulse in accordance with the position along the first axis of the scanning field 114.

[0027] Generally, the non-uniform variation in the optical expansion provided by the expansion optical system 108 combined with the variation in the energy level of the laser light pulse provided by the light source controller 101 provides an improved effective range across the scanning area while reducing overall power consumption. Specifically, in one embodiment, the expansion optical system 108 and the light source controller 101 provide an improved effective range that varies across the scanning field 114, providing a longer effective range in the central area of the scanning field 114 and a shorter effective range in the edge area of the scanning field 114.

[0028] As will be described in more detail below, the expansion optical system 108 implements a non-uniform optical expansion. Generally, this non-uniform optical expansion includes a non-uniform change in the exit pointing angle from the expansion optical system 108. Further, this non-uniform optical expansion may also include non-uniform changes in the beam width and beam divergence of the laser light pulse exiting the expansion optical system 108. Detailed examples of such optical expansions and the expansion optical systems used to implement them will be described in more detail below.

[0029] One problem associated with non-uniform optical expansion is the effect of the optical expansion on the range of the scanning laser device 100. For example, an increase in optical expansion typically increases the change in the emission pointing angle, decreases the beam width, and increases the beam divergence. Thus, non-uniform optical expansion results in a non-uniform decrease in the beam width and a non-uniform increase in the beam divergence. This decrease in the beam width can reduce the effective range of the scanning laser device 100 by reducing the effective size of the receiving aperture of the detector 106. Similarly, the increase in beam divergence can reduce the effective range of the scanning laser device by increasing the relative amount of noise received by the detector 106. Thus, in either case, non-uniform variations in optical expansion can cause non-uniform changes in the effective range of the scanning laser device 100.

[0030] As described above, the light source controller 101 is configured to vary the energy level of the laser light pulses in accordance with the position along the first axis of the scanning field of view 114. The variation in the energy level of the laser light pulses is performed to provide a desired effective range of the sensor while at least partially compensating for the effects of non-uniform optical expansion provided by the expansion optics. For example, in one embodiment, the light source controller 101 is configured to vary the energy in a manner proportional to the non-uniform variation in optical expansion. Thus, laser light pulses that undergo a greater optical expansion are generated at a greater energy level. As will be described in more detail below, this increase in the energy level compensates for the decrease in the effective range that would otherwise occur due to the increase in the amount of optical expansion. Further, by varying the energy level of the laser light pulses in this manner, the overall power consumption of the scanning laser device 100 can be reduced while providing the desired effective range.

[0031] In general, the non-uniform variation of the optical expansion provided by the expansion optical system 108 in combination with the variation of the energy level of the laser light pulse provided by the light source controller 101 provides an improved effective range across the scanning area while reducing overall power consumption. Further, in some embodiments, the scanning laser device 100 is implemented to provide an improved effective range that varies across the scanning field of view 114. Thus, the scanning laser device 100 can be implemented to have different effective ranges in different areas of the scanning field of view 114. These different effective ranges are facilitated by varying the energy level of the laser light pulse by a technique that adjusts both the energy level of the desired effective range and the amount of optical expansion in that area of the scanning field of view 114.

[0032] As a specific example, the expansion optical system 108 and the light source controller 101 are implemented to facilitate a longer effective range in the central area of the scanning field of view 114 and a shorter effective range in the edge area of the scanning field of view 114. Also in this case, when implementing such different effective ranges, the laser light source controller 101 varies the energy level of the laser light pulse to provide these different ranges while compensating for the reduction in the effective range that would result from the variation in the amount of optical expansion. A detailed example of such an embodiment will be described in more detail below.

[0033] The laser light source controller 101 can use various techniques and devices to vary the energy level of the laser light pulse. For example, the laser light controller 101 can be implemented to dynamically change the pulse duration of the laser light pulse. As another example, the laser light controller 101 can be implemented to dynamically change the pulse amplitude of the laser light pulse. As another example, the laser light controller 101 can be implemented to dynamically change the current used to drive the laser. As another example, the laser light controller 101 can be implemented to dynamically change the number of lasers used to generate the pulses. As another example, the laser light controller 101 can be implemented to dynamically change the number of pulses at each scanning point. Also, various combinations of these techniques can be used.

[0034] In some embodiments, the laser light source controller 101 can be implemented as part of a pulse generation circuit. A detailed example of such a pulse generation circuit will be described in more detail below.

[0035] In one embodiment, the non-uniform variation of the optical expansion provided by the expansion optical system 108 includes a non-linear optical expansion rate with respect to the position along the first axis within the scanning field of view. For example, in one more specific embodiment, the non-uniform variation of the optical expansion includes a larger optical expansion with respect to the position of the laser light pulse in the first side region along the first axis as compared to a smaller optical expansion with respect to the position of the laser light pulse in the central region along the first axis between the first side region and the second side region. A detailed example of the non-uniform and non-linear optical expansion rate will be described in more detail below.

[0036] As described above, the extended optical system 108 can be configured to provide a non-uniform variation in the optical expansion of the laser light pulse with respect to the position along the first axis of the scanning field of view 114, and the light source controller 101 is correspondingly configured to vary the energy level of the laser light pulse in response to the position along the first axis of the scanning field of view 114. In some embodiments, the scanning field of view 114 includes a second axis perpendicular to the first axis, and the light source controller 101 is further configured to vary the energy level of the laser light pulse along the second axis within the scanning field of view 114. In other embodiments, the light source controller 101 is further configured to further vary the energy level of the laser light pulse with respect to the positions along the first and second axes in response to road parameters. In other embodiments, the light source controller 101 is configured to vary the energy level of the laser light pulse with respect to the position along the second axis to limit the height of the scanning field of view 114. Detailed examples of these embodiments will be described in more detail below.

[0037] In some embodiments, in addition to the detector 106, the scanning laser device 100 is implemented to include one or more additional detectors. For example, a second detector can be implemented to receive the reflection of the IR laser light pulse of the laser light pulse from within the scanning field of view passing through the optical assembly 104.

[0038] The scanning laser device 100 may also include other elements. For example, the scanning laser device 100 can also include a time-of-flight (TOF) circuit that responds to the detector 106 to measure the distance to an object at a depth measurement point within the scanning field of view.

[0039] In other embodiments, the scanning laser device 100 may also include a virtual protection housing circuit that emits a first IR laser light pulse with a first pulse energy for detecting an object within a short range for a plurality of depth measurement points, and in response to determining that no object exists within the short range, emits at least one second IR laser light pulse having a total second energy level for detecting an object within a long range from the laser light source, where the first energy level is lower than the total second energy level. A specific example of such a virtual protection housing circuit will be described below.

[0040] Referring now to FIG. 2, a more detailed embodiment of the optical assembly 204 is shown. The optical assembly 204 includes optical elements used to scan laser beam pulses across a scanning field of view. The optical assembly 204 is an example of a type of optical assembly that can be used in a LiDAR or other scanning laser device (e.g., scanning laser device 100) according to the embodiments described herein. The optical elements shown in FIG. 2 include beam shaping optics 208, first scanning mirror(s) 210, an expanding optical system 212, and second scanning mirror(s) 214, but this is merely a non-limiting example. Again, during operation of the scanning laser device, the laser light source generates a laser light pulse, and the laser light pulse is scanned along a scanning trajectory (e.g., pattern 112) across a scanning field of view (e.g., scanning field of view 114) by the optical assembly 204.

[0041] For example, the laser light source can include one or more infrared (IR) lasers implemented to generate IR laser light pulses. In one specific example, pulses from multiple IR laser light sources are combined and shaped by the beam shaping optics 208. The beam shaping optics 208 can include any optical system for changing the beam shape of the laser light pulse. For example, the beam shaping optics 208 can include optical elements for changing the beam shape, changing the beam collimation, combining multiple beams, and opening the beam(s).

[0042] The output of the beam shaping optical system 208 is sent to the first scanning mirror 210. Generally, the first scanning mirror 210 provides one axis of motion (e.g., horizontal), and the second scanning mirror 214 provides another, typically orthogonal axis of motion (e.g., vertical). Thus, the first scanning mirror 210 scans the laser beam pulse in one direction (e.g., horizontally), and the second scanning mirror 214 scans in the other direction (e.g., vertically). Further, in a typical implementation of such an embodiment, the first scanning mirror 210 operates to provide a scanning motion at a certain speed (e.g., a relatively slow scanning speed), and the second scanning mirror 214 operates to provide a motion at a different speed (e.g., a relatively fast scanning speed). Together, this causes the laser light pulse to be scanned in a scanning trajectory pattern (e.g., pattern 112). Further, it should be noted that the labels "vertical" and "horizontal" as used herein are somewhat arbitrary, as the horizontal and vertical axes effectively switch when the scanning laser device is rotated 90 degrees.

[0043] The output of the first scanning mirror 210 is sent to the beam expansion optical system 212. Generally, the beam expansion optical system 212 is implemented to expand the scanning field of view in one or more directions. For example, the beam expansion optical system 212 can be implemented to provide angular expansion along the axis of motion of the first scanning mirror 210. Thus, in an example where the first scanning mirror 210 provides a relatively slow speed scan along the horizontal axis, the beam expansion optical system 212 can be implemented to increase the scan angle along the horizontal direction. As a specific example, the first scanning mirror 210 can be implemented to provide a scan angle of 40 degrees in the horizontal direction, and the beam expansion optical system 212 can be implemented to expand the scan angle to 110 degrees, thus expanding the resulting scan trajectory and the size of the scanning field of view.

[0044] To provide this expansion, the expansion optical system 212 can be implemented using one or more lenses, and the one or more lenses are configured to together provide a desired angular expansion. In one specific example, the expansion optical system 212 is implemented with three separate lenses. A detailed description of such an embodiment will be described in more detail below.

[0045] The output of the expansion optical system 212 is sent to the second scanning mirror 214. Also in this case, the first scanning mirror 210 provides one axis of movement (e.g., horizontal), and the second scanning mirror 214 provides another, typically orthogonal axis of movement (e.g., vertical). Also, the first scanning mirror 210 and the second scanning mirror 214 operate at different scanning speeds. In one particular embodiment, the second scanning mirror 214 provides a high-speed scan in the vertical direction, and the first scanning mirror 210 provides a low-speed scan in the horizontal direction.

[0046] Thus, during operation, the optical assembly 204 receives laser light pulses and operates to scan those laser light pulses in a scanning trajectory pattern within the scanning field of view.

[0047] Referring now to FIG. 3A, a representation of the optical expansion in the scanning field of view is shown in graph 300. Specifically, graph 300 shows the expansion of the emission pointing angle as a function of the scanning angle along a first axis, and the first axis also corresponds to the first axis within the resulting scanning field of view. This expansion of the emission angle is an example of the type of optical expansion that can be provided by the expansion optical system of a scanning laser device (e.g., the expansion optical system 108 of FIG. 1, the expansion optical system 212 of FIG. 2). The optical expansion shown in graph 300 is non-uniform with respect to the first axis, and more specifically, results in a non-linear optical expansion with respect to the axis within the scanning field of view. This non-uniform and non-linear optical expansion results in a higher rate of variation of the optical expansion in the side regions of the scanning field of view along the first axis as compared to a lower rate of variation of the optical expansion in the central region.

[0048] In other words, graph 300 shows an optical expansion in which there is a greater change in optical expansion with respect to the position of the laser light pulse along the first axis in the first and second side regions, as compared to the lower change in optical expansion in the central region between the side regions. This is shown by the fact that the slope of the function curve gradually becomes steeper as the distance from the center increases.

[0049] In an exemplary embodiment, the non-linear optical expansion shown in graph 300 can be represented by a higher-order mathematical function (e.g., quadratic and higher-order polynomial functions, etc.). Such a function can be implemented in a scanning laser device and can be used to determine the energy level of the laser light pulse as a function of the scanning angle of the laser light pulse along the first axis. Note that the function curve representing the optical expansion in FIG. 3A is merely an example implementation, and it should be noted that the expansion optical system can be implemented with other types of non-linear and non-uniform expansions.

[0050] Referring now to FIG. 3B, graph 350 shows an exemplary scanning trajectory 352. Scanning trajectory 352 is an example of a type of scanning trajectory that can be generated using a scanning laser device that includes an expansion optical system that provides non-uniform optical expansion with respect to the first axis (e.g., expansion optical system 108 of FIG. 1, expansion optical system 212 of FIG. 2). More specifically, scanning trajectory 352 is an example of a type of trajectory that can be generated with an optical expansion as shown in graph 300 of FIG. 3A. Thus, this scanning trajectory 352 shows the result of a non-uniform and non-linear optical expansion in which a higher expansion variability of the emission angle is created in the side regions of the scanning field along the first axis, as compared to the lower expansion variability of the emission angle that occurs in the central region.

[0051] The scanning trajectory 352 is generated by the movement of one or more scanning mirrors, which provide deflection of the laser light pulses along a first axis and a second axis, and the non-uniform expansion is provided by one or more expansion optical systems. In the illustrated example, the scanning movement along the first axis is a relatively slow movement, and the scanning movement along the second axis is a relatively fast movement. Also, in this example, the movement along the first axis is horizontal, and the movement along the second axis is vertical (note that the labels "vertical" and "horizontal" are somewhat arbitrary since rotating the scanning laser device by 90 degrees will switch the horizontal and vertical axes).

[0052] Finally, note that the scanning trajectory 352 is only an example of a trajectory that may result from non-uniform variations in optical expansion, and many other implementations are possible.

[0053] As described above, variations in optical expansion as shown in FIGS. 3A and 3B can result in variations in the effective range of a scanning laser detector. Specifically, variations in optical expansion can result in variations in beam width and beam divergence, which can result in variations in the effective range of the scanning laser device. Thus, according to the embodiments described herein, a light source controller (e.g., light source controller 101) is configured to provide a desired effective range of the sensor by varying the energy level of the laser light pulses to at least partially compensate for the effects of non-uniform optical expansion provided by the expansion optical system.

[0054] Referring now to FIG. 3C, a diagram of laser light pulse - energy - level adjustment is shown in graph 370. Specifically, graph 370 shows the energy level adjustment as a function of the scanning angle along a first axis, which also corresponds to the first axis within the resulting scanning field of view. It should be noted that the illustrated energy level adjustment can be considered as an increased rate of energy level from a low - power state or a decreased rate of energy level from a high - power state.

[0055] Also in this case, in one embodiment, the light source controller (e.g., light source controller 101) is configured to vary the energy in a manner proportional to the non-uniform variation of the optical expansion. Accordingly, laser light pulses that undergo a greater optical expansion are generated at a greater energy level, and vice versa. This increase in energy level compensates for the decrease in effective range that would otherwise occur due to an increase in the amount of optical expansion. It should be noted that the energy level adjustment shown in graph 370 is non-uniform with respect to the first axis. Specifically, graph 370 shows an embodiment in which there is a greater change in energy level with respect to the position of the laser light pulse along the first axis in the first side region and the second side region, as compared to a smaller change in energy level in the central region between the side regions. Also in this case, such a variation in the laser light pulse energy level can compensate for the effects of the optical expansion shown in FIGS. 3A and 3B and provide the desired effective range for the detector and the scanning laser device.

[0056] As described above, in some embodiments, the scanning laser device (e.g., scanning laser device 100) is implemented to provide an improved effective range that varies across the scanning field of view and has different effective ranges in different areas of the scanning field of view. In these embodiments, these different effective ranges are facilitated by varying the energy level of the laser light pulse in a manner that adjusts both the energy level of the desired effective range within the area of the scanning field of view and the amount of optical expansion within that area of the scanning field of view.

[0057] Referring now to FIG. 4A, a schematic diagram of a scanning laser device 400 is shown. Specifically, FIG. 4A shows a scanning laser device 400 implemented with three different exemplary scanning fields of view 402, 404, and 406, and the three different scanning fields of view 402, 404, and 406 each have different effective ranges and different angular fields of view. As an example, these different effective ranges can be provided by implementing the scanning laser device 400 to operate in different modes at different times during operation, and each of the different modes has a different range and / or a different angular field of view. For example, the scanning laser device 400 can be implemented to alternately switch between different range modes or otherwise switch in response to various factors. In other embodiments described in more detail below, the scanning laser device 400 can be implemented to provide these different ranges between different portions of the same scanning trajectory.

[0058] In the example of FIG. 4A, there are three range modes, namely a short range mode, a medium range mode, and a long range mode. The short range mode provides a scanning field of view 406 having an effective range of 60 meters and a scanning field of view angle of 110 degrees. The medium range mode provides a scanning field of view 404 having an effective range of 120 meters and a scanning field of view angle of 50 degrees. Finally, the long range mode provides a scanning field of view 402 having an effective range of 200 meters and a scanning field of view angle of 25 degrees. Of course, these are merely examples and other implementations are possible.

[0059] In the scanning laser device 400, to implement these different range modes, the light source controller (e.g., the laser light controller 101) varies the energy level of the laser light pulse while compensating for the optical expansion of the expansion optical system (e.g., the expansion optical system 108) to achieve the desired range. The three different angular ranges of the scanning fields of view 402, 404, and 406 can be achieved for these three modes by dynamically changing the angular range of the mirror deflection. In other embodiments, the angular range of the mirror deflection can be maintained constant, and the angular ranges of the scanning fields of view 402, 404, and 406 are changed by selectively not transmitting the laser light pulse when the mirror is outside the desired angular range of the desired scanning field of view at the desired angle. In either case, the scanning laser device 400 can provide the desired effective range and the desired angular range of the scanning field of view for each different operating mode.

[0060] Referring now to FIG. 4B, a representation of the laser light pulse - energy - level adjustment is shown in graph 408. Graph 408 shows the laser light pulse - energy - levels for three range modes, namely, the long - range mode, the medium - range mode, and the short - range mode. These modes correspond to the exemplary scanning fields of view 402, 404, and 406 shown in FIG. 4A. Thus, in the long - range mode, the scanning laser device 400 operates to have a range of 200 meters with a relatively narrow 25 - degree field of view. In the medium - range mode, the scanning laser device 400 operates to have a range of 120 meters and a 50 - degree field of view. In the short - range mode, the scanning laser device 400 operates to have a range of 60 meters and a relatively wide 110 - degree field of view. Thus, the energy level of the laser light pulse is adjusted to provide these desired ranges, taking into account also the non - uniform optical expansion provided by the expansion optical system.

[0061] Graph 408 shows the energy level adjustment for three different modes as a function of the scanning angle along a first axis, where the first axis also corresponds to the first axis within the resulting scanning field of view. In this case, the light source controller (e.g., light source controller 101) is configured to provide a relatively constant high energy level for the long range mode since the relatively narrow field of view limits the optical expansion of these pulses. In this example, the energy level of the laser light pulses is 100% or near 100% of the maximum pulse energy.

[0062] However, for the medium range mode and the short range mode, the light source controller is configured to vary the energy in a manner proportional to the non-uniform variation of the optical expansion over the angular range covered by that mode. This enables achieving the desired range for both modes while compensating for the effects of non-uniform optical expansion.

[0063] In both cases, the energy level of the laser light pulses is 100% or near 100% of the maximum pulse energy at the outer edge of the scanning field of view for that mode, but the energy level rapidly decreases towards the center of the scanning field of view. Specifically, in this example, in the medium range mode, the energy level drops to about 65% of the maximum pulse energy at the center of the scanning field of view, and in the short range mode, the energy level drops to about 33% of the maximum pulse energy. It should be noted that the energy level adjustment also, in this case, is proportional to the optical expansion within the angular range covered by the mode. Thus, in both the short mode and the medium mode, the energy level has a higher rate of change in the side regions where the optical expansion also has a higher rate of change compared to the central region.

[0064] The examples of FIGS. 4A and 4B illustrate an implementation of a scanning laser device 400 that has distinct modes with different effective ranges and scanning fields of view 402, 404, and 406 at different angles. Again, in such an embodiment, the scanning laser device 400 can be implemented to switch modes in various patterns and / or based on various factors. In these examples, each mode had a relatively constant range across its respective scanning field of view. However, in other embodiments, the scanning laser device 400 can instead be implemented to provide these different ranges between different portions of the same scanning frame, effectively providing dynamic range shaping across the scanning field of view. To facilitate this, the scanning laser device 400 can be implemented to vary the effective range at various points within each scanning trajectory or scanning frame. Thus, at these points within the scanning trajectory, the effective range can be increased or decreased to dynamically achieve the desired range across the scanning field of view.

[0065] Referring now to FIG. 4C, a schematic diagram of a scanning laser device 400 with dynamic range shaping is shown. Specifically, FIG. 4C shows a scanning laser device 400 implemented to provide a scanning field of view 410 with three different effective ranges across different angular regions of the scanning field of view 410. Again, such dynamic range shaping can be achieved by implementing the scanning laser device 400 to adjust the pulse energy at different points within the scanning trajectory.

[0066] Specifically, in the example of FIG. 4C, the scanning field of view 410 has a range of 60 meters and has a short-range region 412 corresponding to an extended output angle of 25 degrees to 55 degrees, and -25 degrees to -55 degrees. The scanning field of view 410 similarly has a range of 120 meters and has a mid-range region 414 corresponding to an extended output angle of 12.5 degrees to 25 degrees, and -12.5 degrees to -25 degrees. Finally, the scanning field of view 410 has a range of 200 meters and has a long-range region 416 corresponding to an extended angle of 0 degrees to 12.5 degrees, and 0 degrees to -12.5 degrees. Thus, the scanning laser device 400 provides three different ranges across each scanning trajectory or scanning frame.

[0067] Note that the example of FIG. 4C can be considered as an overlap of the three range modes shown in FIG. 4A. Specifically, this example also provides a "long range area" (e.g., a central area having a range of 200 meters), a "medium range area" (e.g., an intermediate area having a range of 120 meters), and a "short range area" (e.g., an outer area having a range of 60 meters) over each scanning trajectory.

[0068] The scanning laser device 400 can achieve this dynamic range shaping by varying the pulse energy to change the effective range at 25, 12.5 - 12.5, and -25 degrees, while compensating for the effect of the non-uniform optical expansion provided by the expansion optical system by varying the pulse energy. Thus, to implement the scanning laser device 400 to have these different ranges, the light source controller (e.g., the laser light controller 101) varies the energy level of the laser light pulses to compensate for the optical expansion of the expansion optical system (e.g., the expansion optical system 108) and the different desired ranges at various points on the scanning trajectory. Thereby, while significantly reducing the amount of power used compared to a scanning laser device that uses only maximum power pulses, the desired range is achieved in various areas.

[0069] Referring now to FIG. 4D, a representation of the laser light pulse energy level is shown in graph 418. Graph 418 shows the laser light pulse energy level as a function of the scanning angle of the first axis required to achieve three different ranges of the scanning field 410 shown in FIG. 4C, and the first axis also corresponds to the first axis of the resulting scanning field. Also in this case, in this example, the scanning field 410 includes a region having three different ranges, namely, a long range region, a medium range region, and a short range region. Thus, across each scanning trajectory, the laser light energy varies to provide a range of 200 meters across the long range region, a range of 120 meters across the medium range region, and a range of 60 meters across the short range region. Further, the energy level of the laser light pulse is adjusted across the scanning field to compensate for the non-uniform optical expansion provided by the expansion optics within the scanning laser device. Thus, in areas of greater optical expansion, more energy is provided to compensate for the effect of that expansion on the effective range.

[0070] In this case, the light source controller (e.g., light source controller 101) is configured to provide a relatively constant high energy level for the long range region since the relatively narrow field of view limits the optical expansion of these pulses. Thus, the laser light pulse energy level is 100% or near 100% of the maximum pulse energy across the entire long range region.

[0071] However, in the case of the medium range region and the short range region, the light source controller is configured to vary the energy in a manner proportional to the non-uniform variation of the optical expansion across those regions. This makes it possible to achieve the desired range for both the medium range region and the short range region while compensating for the non-uniform optical expansion caused by the expansion optics for these scanning angles.

[0072] It should be noted that the energy level of the laser light pulse is 100% or close to the maximum pulse energy at the outer edge of the region for both the medium-range region and the short-range region, but the energy level rapidly decreases towards the central scanning angle. Therefore, the energy level adjustment is also proportional to the optical expansion within these medium-range and short-range regions in this case. In other words, in both the short-range region and the medium-range region, the energy level has a higher rate of change at the outer angles, which also have a higher rate of change in optical expansion compared to the central scanning angle.

[0073] Graph 418 shows the energy level adjustment that provides the desired range in the long-range region, medium-range region, and short-range region while compensating for the effects of non-uniform optical expansion. It should be noted that this technique also reduces the overall power consumption compared to a system that simply uses the maximum energy level pulse across the entire scanning field. Therefore, this technology can also provide significant power savings for the scanning laser device.

[0074] The scanning laser device 400 shown in FIG. 4C provides a scanning field 410 with three different effective ranges, but this is merely one implementation example, and other implementation examples are also possible. Referring to FIG. 4E here, another schematic diagram of the scanning laser device 400 with dynamic range shaping is shown. Specifically, FIG. 4E shows the scanning laser device 400 implemented to provide a scanning field 420 with five different effective ranges across different angular regions of the scanning field 420. Also in this case, such dynamic range shaping can be achieved by implementing the scanning laser device 400 to adjust the pulse energy at different points within the scanning trajectory so as to provide the desired range and compensate for the optical expansion.

[0075] Referring now to FIG. 4F, another schematic view of a scanning laser device 400 having dynamic range shaping is shown. Specifically, FIG. 4F shows a scanning laser device 400 implemented to provide a scanning field of view 430 having 10 different effective ranges over different angular regions of the scanning field of view 430. Also in this case, such dynamic range shaping can be achieved by implementing the scanning laser device 400 to adjust the pulse energy at different points within the scanning trajectory so as to provide the desired range and compensate for optical expansion.

[0076] Referring now to FIG. 4G, another schematic view of a scanning laser device 400 having dynamic range shaping is shown. Specifically, FIG. 4G shows a scanning laser device 400 implemented to provide an asymmetric scanning field of view 440. In this embodiment, the scanning field of view 440 has 5 different effective ranges in each half of the scanning field of view 440. It should be noted that the angular range and range of each of the different regions can be different. Also in this case, such dynamic range shaping can be achieved by implementing the scanning laser device 400 to adjust the pulse energy at different points within the scanning trajectory so as to provide the desired range and compensate for optical expansion. Referring now to FIG. 4H, another schematic view of a scanning laser device 400 having dynamic range shaping is shown. Specifically, FIG. 4F shows a scanning laser device 400 implemented to provide an asymmetric scanning field of view 450 having different regions with different effective ranges on only one side of the scanning field of view 450. In this embodiment, the scanning field of view 440 has 5 different effective ranges in each half of the scanning field of view 440. Also in this case, such dynamic range shaping can be achieved by implementing the scanning laser device 400 to adjust the pulse energy at different points within the scanning trajectory so as to provide the desired range and compensate for optical expansion.

[0077] Also note that in each of these embodiments, the scanning laser device 400 can achieve significant power savings compared to a device that simply uses maximum energy-level pulses across the entire scanning field of view. Thus, these various embodiments can also provide significant power savings for the scanning laser device while providing the desired scanning coverage. Note that the various examples of dynamic range shaping shown in FIGS. 4C and 4E-4H are merely examples, and many other implementations with different resulting scanning fields of view are possible.

[0078] Referring now to FIGS. 5A and 5B, one use of a scanning laser device (e.g., scanning laser device 100) is shown. Specifically, FIGS. 5A and 5B show a mobile platform having a scanning LiDAR system according to various embodiments. Automobile 502 is a movable platform equipped with LiDAR system 504. The LiDAR system is implemented using the various embodiments described above. (e.g., scanning laser device 100 of FIG. 1) or any of the scanning laser devices and LiDAR systems described herein. Thus, LiDAR system 504 is implemented using an expansion optical system that provides a non-uniform optical expansion (e.g., expansion optical system 108) and a laser light source controller that varies the energy level in a manner proportional to the non-uniform variation of the optical expansion. Specifically, in this example, LiDAR system 504 is implemented using an expansion optical system that provides this non-uniform optical expansion about the horizontal axis rather than the vertical axis.

[0079] The LiDAR system 504 generates an exemplary scanning field of view where different horizontal regions have different effective ranges. Specifically, as shown in FIGS. 5A and 5B, the LiDAR system 504 can be implemented to selectively facilitate a long-range region 506, a mid-range region 510, and a short-range region 510, each of these regions having a different angular range. Again, this can be achieved by operating the LiDAR system 504 in three different range modes, the three different range modes having different field-of-view angles as shown in FIG. 4A. Alternatively, this can be achieved by operating the LiDAR system 504 to provide dynamic range shaping with different regions having different effective ranges, as shown in FIGS. 4C and 4E - 4H.

[0080] To implement these different ranges in the LiDAR system 504, the light source controller varies the energy level of the laser light pulses to compensate for the optical expansion of the beam expander and the different desired ranges. It should be noted that in some embodiments, significant and / or non-uniform optical expansion is provided only along one axis, and the other axis does not undergo significant optical expansion. In these embodiments, the variation of the pulse energy to compensate for the optical expansion occurs only along one axis with significant optical expansion. In the example of FIGS. 5A and 5B, non-uniform optical expansion is provided only along the horizontal axis. Thus, along the vertical axis, the energy level varies only as necessary to achieve the desired range.

[0081] Referring now to FIGS. 5C and 5D, tables 510, 512, and 514 show how such variations in energy level can be implemented in a scanning laser device using dynamic range shaping. Specifically, table 510 shows how the energy level can be varied along the vertical axis using adjustment factors PV1, PV2, and PV3. These adjustment factors provide a desired range for the corresponding vertical region. Similarly, table 512 shows how the energy level can be varied along the horizontal axis using adjustment factors PH1, PH2, PH3, PH4, and PH5. These adjustment factors provide a desired range for the corresponding horizontal region while compensating for non-uniform expansion of the horizontal axis.

[0082] As a specific example, vertical adjustment can be implemented as follows. PV1 = 1.0, PV2 = 0.60, PV3 = 0.30. Again, these adjustment factors are used for the shape of the dynamic range of the vertical axis and are substantially uniform since they do not provide adjustment for non-uniform optical expansion. Horizontal adjustment can be implemented as follows. PH1 = 1.0, PH2 = 0.75, PH3 = 0.90, PH4 = 0.55, PH5 = 0.80. These adjustment factors are non-uniform, reflecting compensation for both range and non-uniform optical expansion on the horizontal axis.

[0083] Finally, table 514 shows how the energy level can be varied across the entire scan area using combined adjustment factors. Specifically, multiplying the corresponding horizontal and vertical adjustment factors yields combined adjustment factors that can be used to compensate the energy levels for the horizontal and vertical regions.

[0084] It should be noted again that this is only an example of a method in which the horizontal and vertical adjustment factors can be used together to change the pulse energy level. For example, in other embodiments, the horizontal and vertical adjustment factors can be combined using other mathematical combination techniques (using a weighted average of the adjustment factors). In still other embodiments, the energy level can be varied by selecting the higher or lower of the horizontal and vertical adjustment factors.

[0085] Referring now to FIGS. 6 and 7, side and top views of a scanning laser device 600 are shown. In one embodiment, the scanning laser device 600 is a light LiDAR system used for object detection and / or 3D map generation. The scanning laser device 600 includes a laser light source 602 and an optical assembly 604. The optical assembly 604 is an example of a type of optical assembly that can be used in a LiDAR or other scanning laser device (e.g., scanning laser device 100) according to the embodiments described herein. Thus, the optical assembly 604 includes various optical elements used to facilitate scanning. FIGS. 6 and 7 are simplified examples, and it should be noted that they do not show all of the elements or features of a fully implemented scanning laser device or optical assembly.

[0086] The optical assembly 604 shown in FIG. 6 includes beam shaping optics 614, a first prism 616, a first scanning mirror assembly 617, one or more first scanning mirrors 618, an expansion optical system including three expansion lenses 620, 622, 624, a second prism 626, a second scanning mirror assembly 627, and one or more second scanning mirrors 628.

[0087] During operation of the scanning laser device 600, the laser light source 602 generates laser light pulses, which are scanned along a scanning trajectory (e.g., pattern 112) across a scanning field (e.g., scanning field 114) by the optical assembly 604. For example, the laser light source 602 can include one or more infrared (IR) lasers driven by a field effect transistor (FET) to generate IR laser light pulses.

[0088] Generally, pulses from multiple IR laser light sources are first combined and shaped by the beam shaping optics 614 and associated optical elements. The beam shaping optics 614 can include any optics for changing the beam shape of the laser light pulses. For example, the beam shaping optics 614 can include a collimating lens, a polarization combiner, an anamorphic prism pair for improving divergence, and other such elements. In one embodiment, a pick-off beam splitter or prism 603 is implemented within the beam shaping optics 614 to direct the reflection towards a detector (not shown in FIGS. 5 and 6) configured for short-range pulse detection.

[0089] The output of the beam shaping optics 614 is sent to a first prism 616 that raises the beam towards the first scanning mirror 618. In the illustrated embodiment, the first scanning mirror 618 provides a horizontal scanning motion, and the second scanning mirror 628 provides a vertical scanning motion. Further, in this example, the first scanning mirror 618 is driven to provide a scanning motion at a relatively slow scanning speed, and the second scanning mirror 628 is driven to provide a motion at a relatively slow scanning speed. However, these are merely examples, and other implementations are possible. Together, this scanning mirror motion causes the laser light pulses to be scanned along the scanning trajectory pattern (e.g., pattern 112). Again, note that the labels "vertical" and "horizontal" as used herein are somewhat arbitrary since rotating the scanning laser device by 90 degrees effectively switches the horizontal and vertical axes.

[0090] The output of the first scanning mirror 618 is sent to three relay lenses 620, 622, 624 that together provide a relay optical system. Generally, the relay optical system is implemented to provide an expansion of the scanning field of view in the horizontal direction.

[0091] Specifically, in this illustrated example, the three relay lenses 620, 622, 624 are implemented to image the output of the first scanning mirror 618 onto the second scanning mirror 628 while providing a non-uniform expansion in the horizontal direction. As a specific example, the first scanning mirror 618 can be implemented to provide a scanning angle of 40 degrees in the horizontal direction, and the relay lenses 620, 622, 624 can be implemented to provide a non-uniform expansion that expands the scanning angle to 110 degrees.

[0092] As described above, the relay lenses 620, 622, 624 can be implemented to provide a non-uniform horizontal expansion. Generally, a non-uniform expansion is one that provides a non-uniform variation in the optical expansion with respect to the position along the first axis of the IR laser light pulse within the scanning field of view of the relay optical system. For example, the amount of expansion can increase or decrease non-uniformly along the horizontal axis.

[0093] In one specific example, the three relay lenses 620, 622, 624 implement a 4F optical system that images the output of the first scanning mirror 618 onto the second scanning mirror 628. Specifically, the three relay lenses 620, 622, 624 provide a 4F optical system with a magnification that varies according to the angle from the first scanning mirror 618. These three relay lenses 620, 622, 624 consequently result in a non-uniform variation in the optical expansion of the output scanning angle provided by the first scanning mirror 618. The second prism 626 receives the output of the third relay lens 624 and directs the beam onto the second scanning mirror 628.

[0094] Referring now to FIG. 8, a scanning light detection and ranging (LiDAR) system 800 according to various embodiments is shown. LiDAR system 800 is another example of a type of scanning laser device that can be implemented in accordance with the embodiments described herein. The system 800 includes a pulse generation circuit 890, an infrared (IR) laser light source 830, a scanning mirror assembly 814 having one or more scanning mirrors 816, and a mirror drive and control circuit 854. The system 800 also includes a first infrared (IR) detector 842, a first time-of-flight (TOF) measurement circuit 844, a 3D point cloud storage circuit 886, a first comparator 848, and a virtual protection housing circuit 880. The system 800 also includes a second IR detector 1842, a second TOF measurement circuit 1844, and a second comparator 1848. As will be described in more detail below, the second IR detector 1842 can be implemented to provide redundant short-range detection.

[0095] The laser light source 830 can be a laser light source such as a laser diode (s) that can emit laser beam pulses 862. The beam pulse 862 impinges on a scanning mirror assembly 814, which is part of, for example, a microelectromechanical systems (MEMS)-based scanner in some embodiments, and is reflected from the scanning mirror 816 to generate a controlled output beam pulse 134. In some embodiments, optical elements are included in the optical path between the laser light source 830 and the mirror (s) 816. For example, the system 800 may include a collimating lens, a dichroic mirror, an expanding optical system, or any other suitable optical element. Also, as described above, the scanning mirror, the expanding optical system, and other elements can cause a retroreflection of the laser light pulse toward the second IR detector 1842 during operation of the system 800.

[0096] The scanning mirror drive and control circuit 854 provides one or more drive signals 855 for controlling the angular movement of the scanning mirror(s) 816 such that the output beam pulse 134 traverses the scan path 840 within the scan field 828. During operation, the laser light source 830 generates modulated light pulses in the non-visible spectrum, and the scanning mirror(s) 816 reflect the light pulses as the beam 834 traverses the scan path 840.

[0097] In some embodiments, the scan path 840 is formed by combining a sawtooth component on a horizontal axis and a sine wave component on a vertical axis. In still further embodiments, the horizontal sweep is also a sine wave. The various embodiments of the present invention are not limited by the waveforms used to control the vertical and horizontal sweeps or the resulting scan path pattern. One axis (e.g., the horizontal axis) is the slow scan axis and the other axis is the fast scan axis.

[0098] The scanning mirror(s) 816 is shown as a single mirror scanning in two axes, but this is not a limitation of the present invention. For example, in some embodiments, the mirror(s) 816 is implemented using two separate scanning mirrors, one for the first scan in one axis and the second scan in the second axis.

[0099] In some embodiments, the scanning mirror(s) 816 includes one or more sensors for detecting the angular position or angular range (either or both dimensions) of the mirror deflection. For example, in some embodiments, the scanning mirror assembly 814 includes a piezoresistive sensor that supplies a voltage proportional to the deflection of the mirror on the high-speed scanning axis. Further, in some embodiments, the scanning mirror assembly 814 includes an additional piezoresistive sensor that supplies a voltage proportional to the deflection of the mirror on the low-speed scanning axis. The mirror position information is returned to the mirror drive and control circuit 854 as one or more SYNC signals 815. In these embodiments, the mirror drive and control circuit 854 includes one or more feedback loops for modifying the drive signal in response to the measured angular deflection of the mirror. Further, in some embodiments, the mirror drive and control circuit 854 includes one or more phase-locked loop circuits for estimating the instantaneous angular position of the scanning mirror based on the SYNC signal.

[0100] The mirror drive and control circuit 854 can be implemented using functional circuits such as a Phase Lock Loop (PLL), filter, adder, multiplier, register, processor, memory, etc. Thus, the mirror drive and control circuit 854 can be implemented in hardware, software, or any combination thereof. For example, in some embodiments, the control circuit 854 is implemented in an Application Specific Integrated Circuit (ASIC). Further, in some embodiments, part of the higher-speed data path control is executed in the ASIC and the overall control is programmable by software.

[0101] The system 800 includes two separator IR detectors, a TOF measurement circuit, and a comparator for detecting the IR laser pulse. Specifically, the system 800 includes a first IR detector 842 and a second IR detector 1842. Generally, the first IR detector 842 is implemented to detect reflections from both short-range and long-range pulses, while the second IR detector provides redundant detection of reflections from low-power short-range pulses to enhance eye safety.

[0102] The first IR detector 842 includes one or more photosensitive devices capable of detecting the reflection of an IR laser light pulse. For example, the first IR detector 842 may include one or more PIN photodiodes, a Silicon Photomultiplier (SiPM), an Avalanche Photo Diode (APD), etc. Each point within the field of view irradiated by the IR laser light pulse (referred to herein as a "measurement point") may or may not reflect some amount of the incident light back to the first IR detector 842. When the first IR detector 842 detects a reflection, the IR detector 842 provides a signal 843 to the first TOF measurement circuit 844.

[0103] The first TOF measurement circuit 844 measures the time of flight (TOF) of the IR laser light pulse to determine the distance to an object within the field of view. In some embodiments, the virtual protection housing circuit 880 provides a timing signal (not shown) corresponding to the emission time of a particular IR laser light pulse to the first TOF measurement circuit 844, and the first TOF measurement circuit 844 measures the TOF of the IR laser light pulse by determining the elapsed time between the emission of the pulse and the reception of the reflection of the same pulse.

[0104] The first TOF measurement circuit 844 can be implemented using any suitable circuit. For example, in some embodiments, the first TOF measurement circuit 844 includes an analog integrator that is reset when the IR pulse is emitted and stopped when the reflected pulse is received. The first TOF measurement circuit 844 may also include an analog-to-digital converter for converting the analog integrator output to a digital value corresponding to the time of flight (TOF) of the IR laser pulse, which corresponds to the distance between the system 800 and the object within the field of view where the light pulse was reflected.

[0105] The 3D point cloud memory device 846 receives X and Y data from the mirror drive and control circuit 854 and distance (Z) data on the node 845 from the first TOF measurement circuit 844. For each detected reflection, three sets (X, Y, Z) are written into the 3D point cloud memory device, resulting in a series of 3D points, herein referred to as a "point cloud". Not all X and Y measurement points within the field of view necessarily have corresponding Z measurement values. Thus, the resulting point cloud may be sparse or dense. The amount of data included in the 3D point cloud is not a limitation of the present invention.

[0106] The 3D point cloud memory device 846 can be implemented using any suitable circuit structure. For example, in some embodiments, the 3D point cloud memory device 846 is implemented as a dual-port memory device that can be written to on one port and read from on a second port. In other embodiments, the 3D point cloud memory device 846 is implemented as a data structure within a general-purpose memory device. In further embodiments, the 3D point cloud memory device 846 is implemented in an application-specific integrated circuit (ASIC).

[0107] The first comparator 848 compares the distance data (Z) on the node 845 with a threshold value. If the distance is less than the threshold value, the first comparator 848 asserts a short-range object detection signal as an input to the OR gate 882. The short-range object detection signal proceeds through the OR gate 882 to the VPH circuit 880 to indicate the detection of an object within the "short range", where the "short range" is determined by the value of the threshold on the node 847. For example, if the threshold is set to a value corresponding to a distance of 5 meters and the detected distance is less than that threshold, an object closer than 5 meters is detected and the VPH circuit 880 is notified by the short-range object detection signal on the node 884.

[0108] The threshold value at the node 847 and the corresponding short-range distance can be modified by the VPH circuit 880 based on any criterion. For example, the threshold value may be a function of the IR laser pulse power, pulse duration, pulse density, wavelength, scanner speed, desired laser safety classification, etc. The method by which the threshold value is determined is not a limitation of the present invention.

[0109] The second IR detector 1842, the second TOF measurement circuit 1844, and the second comparator 1848 operate to provide a redundant short-range object detection function. Redundant short-range object detection provides an additional measure of safety. For example, redundancy ensures continued safe operation in the event that one or more of the IR detectors, TOF measurement circuits, or comparators fail.

[0110] It should be noted that the first IR detector 842 and the second IR detector 1842 receive reflected light pulses via different optical paths. Specifically, the first IR detector 842 receives reflected light along a separate path indicated by 835, while the second IR detector 1842 shares at least a portion of the optical path with the emitted light pulse. Specifically, the reflected light from the scanning field of view reflects back through at least some of the mirrors (plural), the extended optical system, and other elements within the optical assembly, and reaches the second IR detector 1842 along path 1835.

[0111] The second TOF measurement circuit 1844 measures the time-of-flight (TOF) of the IR laser light pulse and determines the distance to an object within the field of view in a manner similar to the first TOF measurement circuit 844. Thus, the second TOF measurement circuit 1844 can be implemented using any suitable circuit, similar to the first TOF measurement circuit 844.

[0112] Similarly, the second comparator 1848 compares the distance data (Z) on node 845 with a threshold value. If the distance is less than the threshold value, the second comparator 1848 asserts a short-range object detection signal as an input to the OR gate 882. In this case as well, this short-range object detection signal proceeds through the OR gate 882 to the VPH circuit 880 to indicate the detection of an object within "short range", where "short range" is determined by the value of the threshold on node 1847. For example, if the threshold value is set to a value corresponding to a distance of 5 meters and the detected distance is less than that threshold, an object closer than 5 meters is detected and the VPH circuit 880 is notified by the short-range object detection signal on node 884.

[0113] Also in this case, the threshold value and the corresponding short-range distance at node 1847 can be modified by the VPH circuit 880 based on any criterion. For example, the threshold value may be a function of IR laser pulse power, pulse duration, pulse density, wavelength, scanner speed, desired laser safety classification, etc.

[0114] In some embodiments, both the detection and TOF measurement circuits operate to detect short-range objects, and only one of the detection and TOF measurement circuits operates to measure long-range distances and / or write to the 3D point cloud memory. For example, in the embodiment represented by FIG. 8, the time of flight measured by either TOF measurement circuit 1844 or TOF measurement circuit 1844 may be used to detect short-range objects, but only the time of flight measured by TOF measurement circuit 844 is used to fill the 3D point cloud.

[0115] The VPH circuit 880 operates to manage the emission level accessible by a method that enables the overall operation to maintain eye safety. For example, in some embodiments, the VPH circuit 880 controls which of "short-range pulses" and "long-range pulses" to generate by setting the pulse energy value on node 885. The emitted pulse energy can be controlled by one or more of pulse power, pulse duration, or pulse count.

[0116] The VPH circuit 880 may also control the timing of the pulses emitted via the timing signal on node 857. In some embodiments, for all measurement points within the field of view, the VPH circuit 880 sends a signal to the pulse generation circuit 890 to generate short-range pulses that can detect objects with very high reliability up to a distance sufficient to provide a virtual protection enclosure. As used herein, the term "short-range pulse" refers to a pulse that is considered to be very short-range and eye-safe. For example, in some embodiments, the energy level of the short-range IR laser light pulse may be maintained below the IEC60825.1 Class 1 accessible emissions limit, such that the short-range IR laser light pulse can be emitted at all measurement points without the risk of damaging the human eye.

[0117] If an object is detected within the short-range distance, the corresponding three sets (X, Y, Z) may be written to the 3D point cloud storage device 846, and the system 800 provides a virtual protection enclosure by not emitting any higher energy pulses at that measurement point. However, if no short-range object is detected, the system 800 may emit one or more "long-range pulses" of higher total energy to detect objects beyond the short-range distance. For example, in some embodiments, the system 800 may emit a short-range IR laser light pulse that is considered eye-safe at a distance of 100 millimeters (mm), which has a 50% probability of detecting a 5% reflective target at 36 meters (m) in bright sunlight. This short-range pulse may have a probability of 1 in 10 billion of not detecting a 10% reflective target at a distance of 12 m. Also, for example, the system 800 may emit a long-range pulse that can detect objects at distances up to 200 m while maintaining eye safety beyond a distance of 4 meters. In this example, the system 800 may emit a short-range pulse with a very high probability of detecting objects within 4 meters and then emit a long-range pulse that can detect an object at 200 meters.

[0118] As used herein, the term "long-range pulse" refers to one or more pulses having a higher total energy than short-range pulses. For example, in some embodiments, a single long-range pulse may be emitted, and the single long-range pulse may have a higher energy than a single short-range pulse. In other embodiments, multiple long-range pulses may be emitted, and the total energy of the multiple long-range pulses may be higher than that of a single short-range pulse.

[0119] The virtual protection housing circuit 880 can be implemented using any suitable circuit structure. For example, in some embodiments, the VPH circuit 880 may include one or more finite state machines implemented using digital logic to send a signal to the signal pulse generation circuit 890 to conditionally emit a long-range pulse in response to short-range object detection. Further, in some embodiments, the VPH circuit 880 may include a processor and memory for providing software programmability such as short-range pulse energy, long-range pulse energy, threshold values, etc. The manner in which the VPH circuit 880 is implemented is not a limitation of the present invention.

[0120] Referring now to FIG. 9, short-range pulses and long-range pulses according to various embodiments of the present invention are shown. Short-range pulse 910 and long-range pulse 930 are examples of IR laser light pulses that can be emitted by a LiDAR (system 800) or other scanning laser device (e.g., scanning laser device 100) at each measurement point. For example, the system may emit a short-range pulse 910 and then conditionally emit one or more of the long-range pulses 930 based on whether a short-range object is detected. The vertical axis of the plot in FIG. 9 shows pulse amplitude, and the horizontal axis shows time. Short-range pulse 910 is shown as being emitted at a first time, and the threshold is shown as representing a second time. The difference between the first time and the second time represents a short-range distance. For example, in some embodiments, the threshold is set to approximately 33 nanoseconds (ns) corresponding to a short-range distance of substantially 5 meters. In some embodiments, short-range pulse 910 has an energy level that is considered eye-safe at very short distances. For example, short-range pulse 910 can be eye-safe at 100 mm from the system 800 from which it is emitted.

[0121] In some embodiments, if a short-range object is detected, the system does not emit a long-range pulse for that measurement point, and the detected distance is written into the 3D point cloud. On the other hand, if no short-range object is detected, one or more long-range pulses 930 are emitted in a manner that maintains eye-safe levels for the proximity emissions. For example, short-range pulse 910 may have an energy level that provides a very high probability of detecting an object within a short-range distance, and long-range pulse 920 may have an eye-safe total energy level at and beyond the short-range distance. If no short-range object is detected, the long-range pulse can follow immediately after the threshold time. For example, long-range pulse 920 may be emitted within 100 ns or 133 ns of the threshold time. The time corresponding to the threshold and the emission of the long-range pulse may vary in various embodiments based on the desired short-range distance and processing time and is not a limitation of the present invention.

[0122] In some embodiments, a single long - range pulse 920 is emitted, and in other embodiments, a series of long - range pulses 930 are emitted for each measurement point. The number of long - range pulses emitted at a single measurement point is not a limitation of the present invention. For example, in some embodiments, a single long - range pulse may be emitted, and the single long - range pulse has higher energy than the short - range pulse. Also, for example, in some embodiments, multiple long - range pulses may be emitted, and each long - range pulse may have the same energy level as the short - range pulse, but the total energy of the multiple long - range pulses is greater than the energy of the short - range pulse.

[0123] Any number of pulses at any energy level may be used and may define multiple ranges. For example, the short range may be defined by the energy of a single short - range pulse. Also, for example, the medium range may be defined by multiple pulses each having the same energy as the short - range pulse, and the long range may be defined by one or more long - range pulses having the same or greater energy than the short - range pulse.

[0124] In some embodiments, the short - range pulse is emitted at all measurement points, and in other embodiments, the short - range pulse is not emitted at all measurement points. For example, the short - range pulse may be emitted at the first measurement point. If no short - range object is detected, the long - range pulse may be emitted at one or more subsequent measurement points without first emitting the short - range pulse. This is possible in some embodiments, in part because the measurement points can be defined as being sufficiently close to each other such that if a short - range object does not occupy a measurement point, it is a valid assumption that the short - range object does not occupy several subsequent measurement points either.

[0125] Generally, a measurement point is a point on a scanning trajectory along which a scanning laser device measures distance. For example, in some embodiments, a LiDAR system emits a short-range pulse at each measurement point to detect whether an object is within a short-range distance, and then conditionally emits one or more long-range pulses as described above. Thus, as used herein, the term "measurement point" does not mean to refer to an infinitely small point in space, but rather to refer to a small, finite, continuous portion of a scanning trajectory. Specifically, an IR laser light beam traverses a finite portion of the scanning trajectory during the round-trip transit time of the short-range and long-range pulses at each measurement point. The measurement point area is also a function of the laser spot size (initial size and divergence) at the distance at which it encounters an object. Thus, a "measurement point" encompasses an area, which may be very small, but the size and location of that area can be a function of many factors.

[0126] The embodiments described herein facilitate reliable detection of these short-range pulses. Again, as described above, in some embodiments, the system may emit a short-range pulse 910 and then conditionally emit one or more of the long-range pulses 930 based on whether a short-range object is detected. In such a system, it is desirable to facilitate reliable detection of the short-range pulses and enable consistent emission of long-range pulses to provide long-range object detection. Returning now to FIG. 8, a second IR detector 1842 may be implemented to facilitate reliable detection of these low-energy short-range pulses.

[0127] Accordingly, the second IR detector 1842 can be implemented using a plurality of sensors configured to receive reflections through at least some of the same scanning mirror assembly 814, beam shaping optics, and other optical elements used to scan the laser light pulse into the scanning field of view. Since the same optical assembly is used by the plurality of sensors to receive laser light reflections, the scanning of the laser light pulse directed into the scanning field of view may also be blocked by damage or obstructions that prevent the plurality of sensors from receiving reflections from the short range pulses. Accordingly, the second IR detector 1842 can more reliably detect short range pulses that have collided with an object within the scanning field of view and reflected back towards the detector, and can thus be used to determine that the long range pulse can be safely emitted. Further, the plurality of sensors within the second IR detector 1842 are configured to at least partially cancel the effects of back reflections from within the optical assembly. By canceling the effects of back reflections from within the optical assembly, the sensitivity of the detector can be improved, particularly for the detection of low energy short range reflections of the laser pulse from within the scanning field of view 828.

[0128] Further, according to the embodiments described herein, the pulse generation circuit 890 can be implemented using a laser light controller configured to vary the energy level of the laser light pulse in accordance with the position along the first axis of the scanning field of view 828. The variation of the energy level of the laser light pulse is performed to provide the desired effective range of the sensor while at least partially compensating for the effects of the non-uniform optical expansion provided by the expansion optics. For example, in one embodiment, the light source controller is configured to vary the energy in a manner proportional to the non-uniform variation of the optical expansion. Accordingly, laser light pulses that undergo a greater optical expansion are generated at a greater energy level. Further, the laser light controller can be configured to vary the energy to facilitate different effective ranges in different scan regions of the scanning field of view 828.

[0129] Referring now to FIG. 10, a flow diagram of a method according to various embodiments is shown. In some embodiments, method 1000 or a portion thereof is performed by a scanning laser device (e.g., LiDAR system 800 of FIG. 8). In other embodiments, method 1000 is performed by a series of circuits or electronic systems. Method 1000 is not limited by the particular type of device that performs the method. The various operations in method 1000 may be performed in the presented order or in a different order. Further, in some embodiments, some of the operations listed in FIG. 4 are omitted from method 1000.

[0130] Method 1000 is shown starting at block 1010 where a short-range pulse energy level is set and a short-range pulse is emitted. In some embodiments, this corresponds to setting the pulse energy level to a value that results in eye-safe operation at a particular distance from the LiDAR system. For example, in some embodiments, the virtual protection housing circuit (e.g., virtual protection housing circuit 880 of FIG. 8) may set the short-range pulse energy level such that a detectable emission at 100 mm results in eye-safe operation, and in other embodiments, the pulse energy level may be set such that a detectable emission at a minimum distance greater than 100 mm results in eye-safe operation.

[0131] If a short-range object is detected at 1020, the 3D points (X, Y, Z) can be written to a 3D point cloud storage device such as 3D storage device 846 (FIG. 8). If no short-range object is detected, at 1040, one or more long-range pulses may be transmitted. As described above, short-range object detection can be achieved by detecting the reflection of the short-range pulse, measuring the flight time of the detected reflection, and comparing that flight time to a threshold. The value of the threshold corresponding to the short-range distance can be set to any suitable value.

[0132] At 1030, one or more long-range pulses are emitted. If an object is detected at 440, 3D points (X, Y, Z) may be written to a 3D point cloud storage device (e.g., the 3D storage device 846 of FIG. 8), and the process continues at 460 at the next measurement point. If no object is detected, the process continues at 1060 at the next measurement point without writing 3D points to the point cloud storage device.

[0133] Referring now to FIG. 11, the graph shows the probability of not detecting an object as a function of distance for various embodiments. The probability curve 1110 is a typical curve that can be shifted left or right based on many parameters including pulse energy level, object reflectivity, ambient light, etc. For example, in very bright sunlight, a short-range pulse that is eye-safe at 100 mm may have a 10% probability of not detecting an object with 20% reflectivity at 20 m. -10 This results in an even lower probability of not detecting an object at closer distances. In this same scenario, a long-range pulse that is eye-safe at 5 m provides a very robust virtual protection enclosure.

[0134] In some embodiments, the threshold corresponding to the energy level of the short-range distance and long-range pulse is set to a value where the eye-safe minimum distance of the short-range distance and long-range pulse is equal. In other embodiments, the threshold corresponding to the energy level of the short-range distance and long-range pulse is set to a value where the short-range distance is greater than the eye-safe minimum distance of the long-range pulse.

[0135] Referring now to FIG. 12, one use of a scanning laser device (e.g., scanning laser device 100) is shown. Specifically, FIG. 12 shows a mobile platform having an eye-safe scanning LiDAR system according to various embodiments. Automobile 1210 is a movable platform equipped with an eye-safe LiDAR system 1220. In some embodiments, the eye-safe LiDAR system 1220 is implemented using any of the various embodiments described herein (e.g., LiDAR system 800 of FIG. 8 or LiDAR system 1300 of FIG. 13) or the scanning laser devices described herein.

[0136] In some embodiments, the energy of the short-range pulse increases when the platform on which the LiDAR system is mounted is in motion. For example, if automobile 1210 has a speed exceeding a threshold value, the energy of the short-range pulse may have a level such that emissions approaching at a minimum distance exceeding 100 mm are at an eye-safe level. In some embodiments, the minimum distance at which approaching emissions are at an eye-safe level can be 1 meter or more. Also, for example, the energy of the short-range pulse may increase with an increase in the platform speed. In some embodiments, the energy of the short-range pulse may gradually increase as the platform accelerates between 2.5 meters per second (m / s) and 25 m / s.

[0137] Increasing the energy level of the short-range pulse can increase the probability of detecting an object within the short range and / or increase the short range at which an object can be detected. FIG. 12 shows an increase in the short range as a result of the increase in the short-range pulse energy.

[0138] In some embodiments, the short-range pulse energy level is set such that the approachable emission is eye-safe at a short distance (e.g., 100 mm or less), and the time threshold is set to a value with a very low probability of not detecting an object. Next, if the speed of the moving platform (e.g., a vehicle) is not faster than the threshold, a short-range pulse is emitted. Instead, if the speed of the moving platform is faster than the threshold, the short-range pulse energy level and the time threshold corresponding to the short-range distance can be increased. In some embodiments, the short-range pulse energy is increased to a level such that the approachable emission is at an eye-safe level at a minimum distance of 1 meter. In other embodiments, the short-range pulse energy is increased to a level such that the approachable emission is at an eye-safe level at a minimum distance greater than or less than 1 meter.

[0139] In some embodiments, the speed of the moving platform can be determined using a speed sensor on the LiDAR system. In other embodiments, the speed information can be obtained from a sensor on the moving platform (e.g., a sensor on a vehicle).

[0140] Referring now to FIG. 13, a scanning light detection and ranging (LiDAR) system 1300 according to various embodiments is shown. The LiDAR system 1300 is another example of a type of scanning laser device that can be implemented in accordance with the embodiments described herein. The LiDAR system 1300 includes a VPH circuit 1384, a pulse generation circuit 1390, a 3D point cloud storage device 1346, an OR gate 1380, and a control circuit 1354. The LiDAR system 1300 also includes a transmission module 1310, a reception module 1330, a TOF and short-range detection circuit 1340, and a TOF and short-range detection circuit 1350.

[0141] The LiDAR system 1300 includes two separate IR detectors for detecting the reflection of IR laser pulses, as well as TOF and short-range detection circuits. Specifically, the receiving module 1330 includes a first IR detector implemented to detect reflections from both short-range pulses and long-range pulses, and the transmitting module 1310 includes a second IR detector that provides redundant detection of reflections from low-power short-range pulses to enhance eye safety.

[0142] The transmitting module 1310 includes an IR laser light source for generating a pulsed laser beam, collimating optics and focusing optics, and one or more scanning mirror assemblies implemented together within an optical assembly for two-dimensionally scanning the pulsed laser beam within the field of view. The transmitting module 1310 also includes an IR laser light detector that shares an optical path with the emitted IR laser light pulse. Exemplary embodiments of the transmitting module are more fully described below with reference to later figures.

[0143] The receiving module 1330 includes an optical device and one or more scanning mirror assemblies for two-dimensionally scanning to direct reflected light from the field of view toward an IR light detector. Exemplary embodiments of the receiving module are more fully described below with reference to later figures.

[0144] The TOF and short-range detection circuits 1340, 1350 include a TOF measurement circuit and a comparator. For example, the TOF and short-range detection circuit 1340 may include a TOF circuit 1844 and a second comparator 1848, and the TOF and short-range detection circuit 1350 may include a TOF measurement circuit 844 and a comparator 848 (FIG. 8).

[0145] As described above with reference to FIG. 8, the control circuit 1354 controls the movement of the scanning mirror in the transmission module 1310. The control circuit 1354 also controls the movement of the scanning mirror in the reception module 1330. During operation, the control circuit 1354 receives mirror position feedback information (not shown) from the transmission module 1310 and also receives mirror position feedback information (not shown) from the reception module 1330. The mirror position feedback information is used to phase-lock the movement of the mirror.

[0146] The control circuit 1354 drives a microelectromechanical (MEMS) assembly having a scanning mirror in the transmission module 1310 using drive signal(s) 1345, and also drives a MEMS assembly having a scanning mirror in the reception module 1330 using drive signal(s) 1347 that move the mirror through an angular range of mirror deflection that defines the size and position of the scanning trajectory 1342 as well as the scanning field of view 1328. Synchronization of the transmit scan and the receive scan enables the receive aperture to accept only photons from that portion of the transmitted field of view where the transmitted energy was transmitted. This results in a significant tolerance to ambient light noise.

[0147] As shown in FIG. 13, two-dimensional scanning is performed in a first dimension (vertical, fast scan direction) and a second dimension (horizontal, slow scan direction). Since the horizontal and vertical axes are switched when the device is rotated 90 degrees, the labels "vertical" and "horizontal" are somewhat arbitrary.

[0148] Also, it should be noted that in the example of FIG. 13, the scanning trajectory 1342 is expanded along the horizontal axis with non-uniform variations in optical expansion. Such expansion can be implemented by using an expansion optical system as described above. For example, the three expansion lenses 620, 622, 624 of FIGS. 6 and 7 can be implemented in the system 1300. In such an implementation, the expansion optical system is implemented in the transmission module 1310 so as to provide non-uniform expansion in the horizontal direction when the laser light is pulsed and scanned within the scanning field 1328. As shown in FIGS. 6 and 7, these three expansion lenses can be implemented between the first scanning mirror 618 and the second scanning mirror 628. Similarly, in such an embodiment, the corresponding optical system (i.e., the scanning mirror and the expansion optical system) is implemented in the reception module 1330 to provide a corresponding non-uniform reduction in the optical expansion for the reception reflection of the laser light pulse from the scanning field 1328.

[0149] Also, as described above, the transmission module 1310 can be implemented using a pulse generation circuit 1390 that includes a laser light controller configured to vary the energy level of the laser light pulse according to the position along the first axis of the scanning field 1328. The variation in the energy level of the laser light pulse is performed to provide a desired effective range of the sensor while at least partially compensating for the effects of the non-uniform optical expansion provided by the expansion optical system. For example, in one embodiment, the light source controller is configured to vary the energy in a manner proportional to the non-uniform variation in optical expansion. Thus, a laser light pulse that undergoes a greater optical expansion is generated at a greater energy level. Further, the laser light controller can be configured to vary the energy to facilitate different effective ranges in different scanning regions of the scanning field 1328.

[0150] Referring now to FIGS. 14 and 15, FIG. 14 shows a side view of the transmission module 1400, and FIG. 15 shows a top view. The transmission module 1400 is an example of a transmission module that can be used in a LiDAR system (e.g., the transmission module 1310 of FIG. 10). The transmission module 1400 includes a laser light source 1410, beam shaping optics 1420, a received energy pickoff device 1460, a mirror 1462, a beam shaping device 1464, an IR detector 1466, a scanner 1428, and output optics 1450.

[0151] In some embodiments, the light source of the laser light source 1410 generates non-visible light such as infrared (IR) light. In these embodiments, the IR detector 1466 detects non-visible light of the same wavelength as the IR detector (FIG. 16 described below) in the receiving module 1600. For example, in some embodiments, the laser light source 1410 may include a laser diode that generates infrared light having a wavelength of substantially 905 nanometers (nm), and the IR detector 1466 detects a reflected light pulse having a wavelength of substantially 905 nm. Also, for example, in some embodiments, the laser light source 1410 may include a laser diode that generates infrared light having a wavelength of substantially 940 nanometers (nm), and the IR detector 1466 detects a reflected light pulse having a wavelength of substantially 940 nm. The wavelength of the light is not a limitation of the present invention. Any visible or non-visible wavelength can be used without departing from the scope of the present invention.

[0152] The laser light source 1410 may include any number or type of emitters suitable for generating a pulsed laser beam. For example, in some embodiments, the laser light source 1410 includes a plurality of laser diodes shown as 1512, 1514, 1516, and 1518 in FIG. 15. The pulsed laser light generated by the laser light source 1410 is combined, collimated, and focused by the beam shaping optics 1420 to generate a pulsed laser beam. For example, the optics 1522, 1524, 1526, 1528 may collimate the laser beam on the fast axis, and the polarization rotator 1523 and the beam combiner 1520 may combine the laser beams, and the optics 1522 may fan out the pulsed laser beam on the slow axis. The beam size and divergence values are not necessarily uniform across various embodiments of the present invention, having higher values in some embodiments and lower values in some embodiments.

[0153] The scanner 1428 receives the pulsed laser beam from the optics 1420 and scans the pulsed beam two-dimensionally. In the embodiments represented by FIGS. 14 and 15, the scanner 1428 includes two separate scanning mirror assemblies 1430, 1440 each including a scanning mirror 1432, 1442, and each scanning mirror scans the beam one-dimensionally. For example, the scanning mirror 1432 scans the pulsed beam in the fast scanning direction, and the scanning mirror 1442 scans the pulsed beam in the slow scanning direction.

[0154] The scanner 1428 is shown as including two scanning mirror assemblies that scan in separate dimensions, but this is not a limitation of the present invention. For example, in some embodiments, the scanner 1428 is implemented using a single biaxial scanning mirror assembly that scans two-dimensionally. In some embodiments, the scanning device uses electromagnetic actuation achieved using a small assembly including an MEMS die and a small subassembly of permanent magnets and an electrical interface, but various embodiments are not limited in this regard.

[0155] The output optical device 1450 operates on the scanning pulse laser beam when the scanning pulse laser beam exits the transmission module. In some embodiments, the output optical device 1450 performs field of view expansion. For example, the scanner 1428 may scan over a maximum angular range of 20 degrees on the fast scanning axis and over a maximum angular range of 40 degrees on the slow scanning axis, and the output optical device 1450 may expand the field of view to 30 degrees on the fast scanning axis and 120 degrees on the slow scanning axis. The relationship between the scanning angle of the scanning mirror and the amount of field of view expansion provided by the output optical device 1450 is not a limitation of the present invention.

[0156] The received energy pickoff device 1460 deflects received light (shown as dotted lines) that shares at least a portion of the transmission optical path with the emitted light pulse (shown as solid lines). The deflected received light is then reflected by the mirror 1462, focused by the optical device 1064, and detected by the IR detector 1466. In some embodiments, the pickoff device 1460 includes a "window" that transmits the pulsed beam generated by the IR laser light source and a reflective outer portion that deflects received energy outside the window. In other embodiments, the pickoff device 1460 is a partial reflector that transmits a portion of the incident light and reflects the remainder. For example, a reflector that transmits 90% of the incident light and reflects 10% of the incident light provides 10% of the light reflected from an object within the field of view to the IR detector 1466. In further embodiments, the pickoff device 1460 may incorporate a polarization beam splitter that transmits the pulsed laser beam (in a first polarization) and picks off received light of a different polarization. This is effective in part due to the fact that reflections are randomly polarized due to Lambertian reflection. In further embodiments, the emitted laser beam and the received energy may be directed to different portions of the scanning mirror, and the pickoff device 1460 may be an offset mirror arranged to reflect one but not the other.

[0157] In this case as well, to facilitate the reliable detection of low-energy short-range pulses, the IR detector 1466 can be implemented using a plurality of sensors configured to receive reflections through at least some of the same optical assemblies used to transmit the laser light pulse into the scanning field of view. Specifically, the IR detector 1466 can be configured to receive the laser light pulse through the same scanning mirrors 1432, 1142, the output optical device 1450, and other optical elements used to transmit the laser light pulse into the scanning field of view. Since the same optical assembly is used by a plurality of sensors to receive the laser light reflection, the scanning of the laser light pulse directed into the scanning field of view may also be blocked by damage or obstructions that prevent the plurality of sensors from receiving reflections from short-range pulses. Thus, the IR detector 1466 can more reliably detect short-range pulses that have collided with an object within the scanning field of view and reflected back towards the detector, and can thus be used to reliably determine when long-range pulses can be safely emitted. Further, the plurality of sensors within the IR detector 1466 are configured to at least partially cancel out the effects of back reflections from within the optical assembly. By canceling out the effects of back reflections from within the optical assembly, the sensitivity of the detector can be improved, particularly for the detection of low-energy short-range reflections of laser pulses from within the scanning field of view.

[0158] Also, as described above, the transmission module 1400 can be implemented using a laser light controller configured to vary the energy level of the laser light pulse in accordance with the position along the first axis of the scanning field of view. The variation of the energy level of the laser light pulse is performed to provide a desired effective range of the sensor while at least partially compensating for the effects of non-uniform optical expansion provided by the expansion optics. For example, in one embodiment, the light source controller is configured to vary the energy in a manner proportional to the non-uniform variation of the optical expansion. Thus, a laser light pulse that undergoes a greater optical expansion is generated at a greater energy level. Further, the laser light controller can be configured to vary the energy to facilitate different effective ranges in different scanning regions of the scanning field of view.

[0159] Referring now to FIGS. 16 and 17, FIG. 16 shows a side view of the receiving module 1600, and FIG. 17 shows a top view. The receiving module 1600 is an example of a receiving module that can be used in a LiDAR system (e.g., the receiving module 1330 of FIG. 13). The receiving module 1600 includes an IR detector 1610, a folding mirror 1612, imaging optics 1620, a band-pass filter 1622, a scanner 1628, and output optics 1650.

[0160] The scanning mirror assemblies 1630 and 1640 are similar or identical to the scanning mirror assemblies 1430 and 1440, and the output optics 1650 are similar or identical to the output optics 1450. The band-pass filter 1422 passes the wavelength of the light generated by the laser light source 1410 and blocks ambient light of other wavelengths. For example, in some embodiments, the laser light source generates light at 905 nm, and the band-pass filter 1622 passes light at 905 nm.

[0161] The imaging optics 1620 image a portion of the field of view onto the IR detector 1610 after reflection by the folding mirror 1612. Since the scanner 1628 is scanned in synchronization with the scanner 1428, the detector 1610 always collects light from the measurement points irradiated by the scanned pulsed beam.

[0162] FIG. 18 is a perspective view of an integrated photonics module according to various embodiments of the present invention. The integrated photonics module 1800 includes both the transmitting module 1400 (FIGS. 14 and 15) and the receiving module 16 (FIGS. 16 and 17). An integrated photonics module 1800 having a rectangular housing in which the transmitting module 1400 and the receiving module 1600 are arranged side by side is shown. In some embodiments, the transmitting module 1400 and the receiving module 1600 are arranged one on top of the other.

[0163] In the foregoing detailed description, reference has been made to the accompanying drawings that illustrate specific embodiments in which the invention may be practiced. These embodiments have been described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that the various embodiments of the invention are different but not necessarily mutually exclusive. For example, the specific features, structures, or characteristics described herein in connection with one embodiment may be implemented within other embodiments without departing from the scope of the invention. Further, it is to be understood that the position or arrangement of the individual elements within each disclosed embodiment may be changed without departing from the scope of the invention. Accordingly, the foregoing detailed description is not to be construed in a limiting sense, and the scope of the invention is defined only by the appended claims construed in accordance with their proper scope, together with the full scope of equivalents to which the claims are entitled. In the drawings, like reference numerals refer to the same or similar functions throughout the several views.

[0164] Although the invention has been described in connection with specific embodiments, it is to be understood that modifications and variations can be used without departing from the scope of the invention as will be readily appreciated by those skilled in the art. Such modifications and variations are considered to be within the scope of the invention and the appended claims.

Claims

Claim 1 a laser light source configured to generate laser light pulses; an optical assembly including an expanding optical system and a beam scanning optical system for scanning the laser light pulses within a scanning field, the expanding optical system providing a non-uniform variation in the optical expansion of the laser light pulses with respect to a position along a first axis within the scanning field; a detector for detecting reflections of the laser light pulses from within the scanning field; a light source controller configured to control the laser light source to vary the energy level of the laser light pulses in proportion to the non-uniform variation in the optical expansion with respect to the position along the first axis within the scanning field; comprising; wherein the scanning optical system includes a horizontal scanning mirror and a vertical scanning mirror, and the expanding optical system includes a first lens, a second lens, and a third lens, and the first lens, the second lens, and the third lens are disposed between the horizontal scanning mirror and the vertical scanning mirror. Claim 2 The apparatus according to claim 1, wherein the non-uniform variation in the optical expansion with respect to a position along the first axis within the scanning field includes a non-linear expansion rate with respect to a position along the first axis within the scanning field. Claim 3 The apparatus according to claim 1, wherein the non-uniform variation in the optical expansion with respect to a position along the first axis within the scanning field includes a greater optical expansion with respect to the position of the laser light pulses in a first side region along the first axis compared to a smaller optical expansion with respect to the position of the laser light pulses in a central region along the first axis between the first side region and a second side region. Claim 4 The apparatus according to claim 1, wherein the non-uniform variation in the optical expansion includes a non-uniform variation in the emission pointing angle and a non-uniform variation in the beam width. Claim 5 The apparatus according to claim 1, wherein the scanning field includes a second axis perpendicular to the first axis, and the light source controller is further configured to vary the energy level of the laser light pulses along the second axis within the scanning field. Claim 6 The apparatus according to claim 5, further configured to further vary the energy level of the laser light pulse with respect to the position along the first axis and the second axis in response to the light source controller providing different effective ranges to different regions of the scanning field of view.

7. The apparatus according to claim 5, wherein the second axis includes a vertical axis, and the light source controller is configured to vary the energy level of the laser light pulse with respect to the position along the second axis so as to provide different effective ranges to different vertical regions.

8. The apparatus according to claim 1, further configured to further vary the energy level of the laser light pulse with respect to the position along the first axis so that different angular regions of the scanning field of view along the first axis have different effective ranges, in order to dynamically shape the effective range.

9. The scanning field of view includes a second axis perpendicular to the first axis, and the light source controller is further configured to further vary the energy level of the laser light pulse with respect to the position along the second axis so that different angular regions of the scanning field of view along the second axis have different effective ranges, in order to dynamically shape the effective range, the apparatus according to claim 8.

10. The apparatus according to claim 1, further configured to further vary the energy level of the laser light pulse with respect to the position along the first axis for each scanning trajectory so that the light source controller dynamically shapes the effective range to generate at least a relatively long-range region, a mid-range region, and a relatively short-range region in the center of the scanning field of view.

11. The apparatus according to claim 1, wherein the apparatus is mounted on a mobile platform.

12. A time-of-flight (TOF) circuit responsive to the detector to determine the distance from the detected reflection to a depth measurement point within the scanning field of view, For a plurality of depth measurement points, a first laser light pulse is emitted to the laser light source at a first energy level to detect an object within a short range, and in response to determining that no object exists within the short range, at least one laser light pulse having a total second energy level is emitted to the laser light source to detect an object within a long range, and a virtual protection housing circuit in which the first energy level is lower than the total second energy level; The apparatus according to claim 1, further comprising.

13. A laser light source configured to generate an infrared (IR) laser light pulse; An optical assembly, the optical assembly including beam shaping optics, an expanding optics, and scanning optics for scanning the IR laser light pulse into a scanning field of view, the scanning field of view including a central region, and a first side region and a second side region on both sides of the central region, the expanding optics providing a non-uniform variation in the optical expansion of the IR laser light pulse with respect to a horizontal position along a horizontal axis within the scanning field of view, the increase in the optical expansion of the IR laser light pulse with respect to the horizontal position being greater in the first side region and the second side region, and the increase in the optical expansion of the IR laser light pulse with respect to the horizontal position being smaller in the central region, an optical assembly; A first IR detector for detecting the reflection of the IR laser light pulse from within the scanning field of view; A time-of-flight (TOF) circuit that measures the distance to an object at a depth measurement point within the scanning field of view in response to the first IR light detector; A light source controller configured to control the laser light source to vary the energy level of the IR laser light pulse according to the horizontal position of the IR laser light pulse along the horizontal axis in a manner proportional to the greater increase in the optical expansion of the IR laser light pulse with respect to the horizontal position in the first side region and the second side region, and the smaller increase in the optical expansion of the IR laser light pulse with respect to the horizontal position in the central region; An apparatus comprising The scanning optical system includes a horizontal scanning mirror and a vertical scanning mirror, and the expansion optical system includes a first lens, a second lens, and a third lens, and the first lens, the second lens, and the third lens are arranged between the horizontal scanning mirror and the vertical scanning mirror, the device.

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