An eye-safe long-range LIDAR system using actuators

Abstract

The LIDAR system includes a plurality of lasers generating optical beams having a FOV. A plurality of detectors are positioned where the FOV of at least one of the plurality of optical beams generated by the plurality of lasers overlaps the FOV of at least two of the plurality of detectors. A lens system collimates and projects the optical beams generated by the plurality of lasers. An actuator is coupled to at least one of the plurality of lasers and the lens system and causes relative movement between the plurality of lasers and the lens system in a direction orthogonal to an optical axis of the lens system to cause relative movement between the FOV of the optical beams generated by the plurality of lasers and the FOV of the detector.

Description

[Background technology]

[0001] The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described in the present application in any way.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This application is a non-provisional adaptation of U.S. Provisional Patent Application No. 62 / 854,782, entitled "Eye-Safe Long-Range LIDAR System Using Actuator," filed May 30, 2019. The entire contents of U.S. Provisional Patent Application No. 62 / 854,782 are incorporated herein by reference.

[0003] introduction Autonomous, self-driving, and semi-autonomous vehicles use a combination of different sensors and technologies, such as radar, image recognition cameras, and sonar, for detection and location of surrounding objects. These sensors enable numerous improvements in driver safety, including collision warning, automatic emergency braking, lane departure warning, lane keeping assist, adaptive cruise control, and piloted driving. Among these sensor technologies, Light Detection and Ranging (LIDAR) systems play a key role, enabling real-time, high-resolution 3D mapping of the surrounding environment. For LIDAR systems to be widely deployed in large quantities, they need to be both low-cost and reliable, and physically small.

[0004] As LIDAR systems become more widely available and market prices fall, they will also begin to be deployed in many other applications, such as security surveillance, industrial robots, and drones. The application requirements for these other applications, and within the autonomous vehicle space itself, are widely varying. The maximum range, angular resolution, and frame rate required for an autonomous car capable of navigating at high speeds may substantially exceed the requirements for an industrial robot moving inside a building. In such cases, the cost and performance of the LIDAR system are optimized to provide the best match with the application specifications. Summary of the Invention [Means for solving the problem]

[0005] The present teachings relate to Light Detection and Ranging (LIDAR), a remote sensing method that uses laser light to measure distance (range) to objects. Autonomous vehicles use LIDAR systems to generate highly accurate 3D maps of the surrounding environment with high resolution. The systems and methods described herein are directed to providing a pulsed time-of-flight (TOF) LIDAR system with a high level of reliability while also maintaining a long measurement range and low cost. One aspect of the present teachings focuses on optimizing the entire LIDAR system with respect to cost, while still providing excellent reliability and performance in a small physical size.

[0006] The systems and methods described herein providing pulsed TOF LIDAR are also configured to maintain Class 1 eye safety. A Class 1 eye safety rating means that the system is safe under all conditions of normal use. To maintain Class 1 eye safety, the laser light energy or laser light power cannot exceed the Maximum Permissible Exposure (MPE) level as defined by U.S. and international safety standards. However, the measurement range of the LIDAR system is highly dependent on the maximum transmitted light pulse energy or power level. Therefore, it is desirable for automotive LIDAR systems to purposefully operate as close to the Class 1 MPE limit as feasible.

[0007] Given that all LIDAR systems operating at the same wavelength will be subject to the same MPE limit, further improvement in range for one LIDAR system versus another operating at a power level near the MPE power limit must occur by innovating aspects of the optical system. One aspect of the present teachings is a LIDAR system that uses a highly collimated laser beam in which all of the energy is delivered within a small FOV. Such a configuration provides a relatively long measurement range compared to a system in which the same amount of laser light is distributed over a wider FOV. That is, the use of a highly collimated laser beam in combination with a receiver design that allows measurement over a similarly small field of view (FOV) results in a desirable ratio of reflected signal power to background light level that improves ranging capabilities.

[0008] One type of known LIDAR system is the so-called flash LIDAR system, which employs an emission source that emits laser light over a wide FOV. Some flash LIDAR systems are also solid-state with no moving parts, while others use a mirror that scans in one direction, illuminating a "line" that incrementally sweeps the entire field of view. Solid-state flash LIDAR systems with no moving parts must illuminate the entire scene with a single illumination event. However, for LIDAR systems operating at the MPE limit of Class 1 eye safety, the wide FOV illuminated by a solid-state flash LIDAR significantly limits the measurement range compared to systems in which the light from the emission source is highly collimated.

[0009] It should be understood that a measurement or measurement point in a LIDAR system is produced by processing a specific detected signal produced by a specific illumination at a target range. The TOF is calculated based on this specific detected signal. The specific detected signal for the measurement point can be generated by a single detector or multiple detectors depending on how the system is controlled as described further herein. The specific detected signal for the measurement point can also be generated by a single laser or multiple lasers depending on how the system is controlled.

[0010] Some pulsed TOF LIDAR systems according to the present teachings use collimated transmitter laser beams with optical power / energy at or just below the MPE limit for Class 1 eye safety, providing significant range increase compared to conventional flash LIDAR systems. In addition, some pulsed TOF LIDAR systems according to the present teachings use pulse averaging and / or pulse histogramming of multiple laser pulses to improve the signal-to-noise ratio (SNR), which further improves ranging. These LIDAR systems employ very high single pulse frame rates, well above 60 Hz and even up to several kHz, allowing for multiple pulse averaging.

[0011] One important performance goal of automotive LIDAR systems is the angular resolution of the optical system. High angular resolution is required for automotive LIDAR systems in order to be able to clearly define distinct objects in space and / or perform object identification through image analysis. Currently, automotive LIDAR systems require angular resolution that is less than about 0.2°. These systems would benefit from even higher resolution, if achievable.

[0012] Furthermore, there should not be any "gaps" in the footprint between measurement points, especially at long distances. To illustrate why there should not be such gaps, consider a practical use case of a 200 meter range. An angle of 0.2° at 200 meters corresponds to a lateral distance of 0.7 meters. Since a typical person is approximately 0.15 meters wide, if the resolution is 0.2° and the collimated laser beam diameter at 200 meters is less than 0.7 meters, the LIDAR system may be considered as potentially missing the presence of a person completely at a range of 200 meters.

[0013] Reliability is also an important aspect of LIDAR systems designed for autonomous vehicles. The operating environment is particularly challenging for automotive LIDAR systems. LIDAR sensor failure can result in a collision and can also disrupt vehicle operation. LIDAR systems that do not have moving parts are generally more reliable compared to LIDAR systems that use rotating parts or large scanning mirrors. Moving parts are subject to mechanical wear and have a limited lifespan. The LIDAR system of the present teachings preferentially uses "frictionless" mechanisms that include motion but are not subject to wear to the same extent as motors or other large scanning mirrors. The present invention provides, for example, the following items. (Item 1) 1. A light detection and ranging (LIDAR) system, comprising: a) a plurality of lasers, each of the plurality of lasers, when energized, generating an optical beam having a field of view (FOV); b) a plurality of detectors formed in an array and positioned in optical paths of optical beams generated by the plurality of lasers, wherein an FOV of at least one of the plurality of optical beams generated by the plurality of lasers overlaps an FOV of at least two of the plurality of detectors; c) a lens system positioned in an optical path of the optical beams generated by the plurality of lasers in front of the plurality of optical detectors, the lens system collimating and projecting the optical beams generated by the plurality of lasers; d) an actuator coupled to at least one of the plurality of lasers and the lens system, the actuator causing relative movement between the plurality of lasers and the lens system in a direction perpendicular to an optical axis of the lens system to cause relative movement between the FOV of the optical beams generated by the plurality of lasers and the FOV of the detector; A LIDAR system equipped with (Item 2) 2. The LIDAR system of claim 1, wherein at least some of the plurality of lasers are vertical cavity surface emitting lasers. (Item 3) 2. The LIDAR system of claim 1, wherein at least some of the plurality of lasers comprise two-dimensional monolithic vertical cavity surface emitting lasers. (Item 4) 2. The LIDAR system of claim 1, wherein the multiple lasers are configured to maintain class 1 eye safety within the FOV of each of the multiple lasers. (Item 5) 2. The LIDAR system of claim 1, wherein at least some of the plurality of lasers are configured to be energized using a matrix addressable controller. (Item 6) 2. The LIDAR system of claim 1, wherein at least some of the plurality of detectors comprise single photon avalanche diode (SPAD) detectors. (Item 7) 2. The LIDAR system of claim 1, wherein at least some of the plurality of detectors comprise silicon photomultiplier (SiPM) detectors. (Item 8) Item 2. The LIDAR system of item 1, wherein the actuator comprises a flexure-based actuator. (Item 9) 2. The LIDAR system of claim 1, wherein the actuator comprises a voice coil. (Item 10) 2. The LIDAR system of claim 1, wherein the actuator comprises a piezoelectric translator. (Item 11) Item 2. The LIDAR system of item 1, wherein the actuator comprises a shape memory translator. (Item 12) 2. The LIDAR system of claim 1, wherein the actuator is configured to cause relative motion between the lasers and the lens system such that the optical beams move in a two-dimensional pattern. (Item 13) Item 13. The LIDAR system of item 12, wherein the two-dimensional pattern includes a rectangular pattern. (Item 14) 2. The LIDAR system of claim 1, wherein the actuator is configured such that relative movement between the FOV of the optical beams generated by the multiple lasers and the FOV of the detector changes the angular resolution of the LIDAR system. (Item 15) 2. The LIDAR system of claim 1, wherein the actuator is configured such that relative motion between the FOV of the optical beams generated by the multiple lasers and the FOV of the detector is selected such that overlapping FOVs of the optical beams generated by the multiple lasers cover an entire LIDAR system FOV. (Item 16) 2. The LIDAR system of claim 1, wherein the actuator is configured such that relative motion between the FOV of the optical beams generated by the multiple lasers and the FOV of the detector is substantially zero during the period when laser pulses are being transmitted. (Item 17) 2. The LIDAR system of claim 1, further comprising a controller having a plurality of outputs electrically connected to inputs of at least some of the plurality of lasers, the controller selecting a particular laser within the plurality of lasers to be energized. (Item 18) 20. The LIDAR system of claim 17, wherein the controller further comprises a plurality of inputs electrically connected to a plurality of outputs of at least some of the plurality of detectors, the controller being configured to select a particular detector to be monitored. (Item 19) 1. A method for light detection and ranging (LIDAR), comprising: a) energizing selected ones of a plurality of lasers such that each selected one of the lasers generates an optical beam having a field of view (FOV); b) collimating the optical beams generated by the selected ones of the plurality of lasers with a lens system and projecting them onto a plurality of detectors, wherein an FOV of at least one of the plurality of optical beams generated by the plurality of lasers overlaps an FOV of at least two of the plurality of detectors; c) moving the lasers relative to the lens system, thereby causing relative motion between the FOV of the optical beams generated by the lasers and the FOV of the detectors; d) monitoring a selected one of the plurality of detectors within an FOV of at least one of the plurality of optical beams generated by the selected one of the plurality of lasers; A method comprising: (Item 20) 20. The method of claim 19, wherein energizing selected ones of the plurality of lasers includes firing a pattern of lasers such that a predetermined optical power level is not exceeded within any individual optical beam FOV. (Item 21) 20. The method of claim 19, wherein energizing selected ones of the plurality of lasers includes firing a pattern of lasers such that class 1 eye safety limits are not exceeded within any individual optical beam FOV. (Item 22) 20. The method of claim 19, wherein energizing selected ones of the plurality of lasers includes firing a pattern of lasers such that a predetermined optical power level is not exceeded within any overlapping optical beam FOV. (Item 23) 20. The method of claim 19, wherein energizing selected ones of the plurality of lasers includes firing a pattern of lasers such that class 1 eye safety limits are not exceeded within any overlapping optical beam FOV. (Item 24) 20. The method of claim 19, wherein the relative motion between the plurality of lasers and the lens system is in a direction perpendicular to an optical axis of the lens system. (Item 25) 20. The method of claim 19, wherein the relative motion is about half the physical distance between emitters of at least some of the plurality of lasers. (Item 26) 20. The method of claim 19, wherein relative motion between the multiple lasers and the lens system does not occur during the time that laser pulses are transmitted. [Brief description of the drawings]

[0014] In accordance with preferred exemplary embodiments, the present teachings, together with further advantages thereof, are more particularly described in the following detailed description taken in conjunction with the accompanying drawings. Those skilled in the art will appreciate that the drawings described below are for illustrative purposes only. The drawings are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present teachings. The drawings are not intended to limit the scope of the applicant's teachings in any way.

[0015] [Figure 1A] FIG. 1A illustrates a schematic diagram of a known solid-state LIDAR system.

[0016] [Figure 1B] FIG. 1B illustrates a two-dimensional projection of the system field of view (FOV) of the LIDAR system of FIG. 1A.

[0017] [Figure 2A] FIG. 2A illustrates a schematic diagram of a 2D monolithic VCSEL array with 256 separate laser emitters, each emitter corresponding to a single large aperture that can be used in some embodiments of the LIDAR emitter of the present teachings.

[0018] [Figure 2B] FIG. 2B illustrates a schematic diagram of a 2D monolithic VCSEL array with 256 separate laser emitters, each emitter having 9 subapertures that can be used in a LIDAR emitter according to the present teachings.

[0019] [Figure 3A] FIG. 3A illustrates a two-dimensional projection of a LIDAR system FOV for operation of an embodiment of a LIDAR system according to the present teachings, which results in gaps between the beams when the divergence of the 16 laser emitter beams is imaged onto a detector array.

[0020] [Figure 3B]FIG. 3B illustrates a two-dimensional projection of the LIDAR system FOV for a LIDAR system in which the divergence of the individual laser emitter beams is identical to that shown in FIG. 3A, but the number of laser emitters is increased to 64 to eliminate any gaps between the beams when imaged onto the detector array.

[0021] [Figure 4] FIG. 4 illustrates a schematic diagram of one embodiment of an emitter of the present teachings in which each laser emitter in the array corresponds to a particular projection angle.

[0022] [Diagram 5] FIG. 5 illustrates a two-dimensional projection of the LIDAR system FOV of an embodiment of a LIDAR system according to the present teachings in which the divergence of the individual laser emitter beams is the same as the system described in connection with FIG. 3A and relative motion between the lens system and the laser array is used to scan in the pattern as shown.

[0023] [Figure 6A] FIG. 6A illustrates one embodiment of a LIDAR system according to the present teachings that uses two physically separate emitters.

[0024] [Figure 6B] FIG. 6B illustrates a two-dimensional projection of the LIDAR system FOV of an embodiment of the LIDAR system of FIG. 6A at one relative position of the lens systems and array in the two transmitters.

[0025] [Figure 6C] FIG. 6C illustrates a two-dimensional projection of the LIDAR system FOV of an embodiment of the LIDAR system of FIG. 6A at another relative position of the lens system and the array in the two transmitters.

[0026] [Figure 7]FIG. 7 illustrates a two-dimensional projection of a LIDAR system FOV for one embodiment of a LIDAR system in accordance with the present teachings, in which the laser beam is nominally rectangular in shape and the FOV of a single pixel in the detector array is smaller than the laser beam.

[0027] [Figure 8] FIG. 8 illustrates an embodiment of a LIDAR system emitter according to the present teachings in which relative motion of a microlens array is used to change the projection angle of a laser beam. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The present teachings will now be described in more detail with reference to exemplary embodiments thereof as illustrated in the accompanying drawings. While the present teachings will be described in conjunction with various embodiments and examples, it is not intended that the present teachings be limited to such embodiments. Rather, the present teachings encompass various alternatives, modifications, and equivalents as will be understood by those skilled in the art. Those skilled in the art with access to the teachings herein will recognize additional implementations, modifications, and embodiments that are within the scope of the present disclosure as described herein, as well as other fields of use.

[0029] References herein to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present teachings. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment.

[0030] It should be understood that the individual steps of the methods of the present teachings can be performed in any order and / or simultaneously so long as the present teachings remain operable. Further, it should be understood that the apparatus and methods of the present teachings can include any number or all of the described embodiments so long as the present teachings remain operable.

[0031] FIG. 1A illustrates a schematic diagram of a known solid-state LIDAR system. The system illustrated in FIG. 1A does not employ a flash emitter that illuminates the entire system field of view all at once. A laser array 102 generates optical beams in various patterns. The optical beams are emitted from emitters in the array 102 when the emitters are activated by control pulses. One or more emitters can be activated according to a particular sequence. The optical beams from the lasers in the laser array 102 propagate through a generic emitter optics 104 that projects the optical beams onto a target 106 at a target plane 110. The target 106 in this particular example is an automobile 106, but it should be understood that the target can be any object.

[0032] A portion of the light from the incident optical beam is reflected by the target 106. These portions of the reflected optical beam share the receiver optics 112. The detector array 114 receives the reflected light projected by the receiver optics 112. In various embodiments, the detector array 114 is solid state with no moving parts. The detector array 114 typically has fewer individual detector elements than the transmitter array 102 has individual lasers.

[0033] The measurement resolution of the LIDAR system 100 is not determined by the size of the detector elements in the detector array 114, but instead by the number of lasers in the emitter array 102 and the collimation of the individual optical beams. In other words, the resolution is limited by the field of view of each optical beam. A processor (not shown) in the LIDAR system 100 performs a time-of-flight (TOF) measurement that determines the distance of the target 106 from the optical beams emitted by the laser array 102 detected at the detector array 114.

[0034] One feature of the LIDAR system according to the present teachings is that individual lasers and / or groups of lasers in the emitter array 102 can be individually controlled. Each individual emitter in the emitter array can be fired independently, with each laser emitter emitting an optical beam corresponding to a three-dimensional (3D) projection angle that subtends only a portion of the total system field of view. An example of such a LIDAR system is described in commonly assigned U.S. Patent Publication No. 2017 / 0307736 A1. The entire contents of U.S. Patent Publication No. 2017 / 0307736 A1 are incorporated herein by reference.

[0035] Another feature of the LIDAR system according to the present teachings is that the detectors and / or groups of detectors in the detector array 114 may also be individually controlled. This independent control of the individual lasers and / or groups of lasers in the emitter array 102 and the detectors and / or groups of detectors in the detector array 114 provides a variety of desirable operating characteristics, including control of the system field of view, optical output levels, and scan patterns.

[0036] FIG. 1B illustrates a two-dimensional projection of the system field of view 150 of the LIDAR system of FIG. 1A. Referring to both FIG. 1A and FIG. 1B, the field of view of an individual detector in the detector array is represented by a small square 152. The illuminated measurement point resulting from the detected signal associated with an individual emitter in the emitter laser array 102 is illustrated by a circle 154. A single 3D measurement point in the total field of view of the LIDAR system of FIG. 1A is shown as a specific dark circle 158 corresponding to a specific individual laser in the laser array. It can further be seen in FIG. 1B that this measurement point belongs to an individual detector, and the field of view of that individual detector in the detector array 114 is shown with a square 156 having a cross-hatched pattern for identification. This figure illustrates that the 3D resolution of some embodiments of the LIDAR system is determined by the number of lasers, since each laser corresponds to a specific angular projection angle that results in the size of the circle 154 at the target range, and the relative size of the circle 154 and the square 152 representing the field of view of the individual detector element.

[0037] Thus, by controlling specific individual lasers or groups of lasers in the emitter array and / or individual lasers or groups of lasers of the detectors in the receive array, a desired field of view can be established. Various system fields of view can be established using different relative fields of view for individual emitters or groups of emitters and / or individual detectors or groups of detectors. Fields of view can be established to yield specific performance metrics and / or combinations thereof. These performance metrics include, for example, improved signal-to-noise ratio, longer or controlled range, eye-safe operating power levels, and lower or higher controllable resolution. Importantly, these performance metrics can be modified during operation to optimize LIDAR system performance.

[0038] The LIDAR system according to the present teachings uses an array drive control system capable of providing selective control of specific laser devices in an array of laser devices to illuminate a target according to a desired pattern. The LIDAR system according to the present teachings can also use an array of detectors that generate detector signals that can be processed independently. As a result, a feature of the LIDAR system according to the present teachings is the ability to provide various operational capabilities from a LIDAR system that exclusively involves electrical and non-mechanical and / or non-moving parts including a fixed array of emitters and a fixed array of detectors with both transmit and receive optical beams projected using shared transmit and receive optics. Such a LIDAR system configuration can also result in a flexible system that is small in size, reliable in operation, and relatively low cost.

[0039] One feature of the LIDAR systems of the present teachings is that they rely on laser arrays to generate optical beams and detector arrays to receive a portion of the light from these optical beams reflected from the target. Thus, they benefit from many of the characteristics of solid-state components in that they are relatively small in size, reliable in operation, and low in cost. Various detector technologies can be used to build detector arrays for LIDAR systems according to the present teachings. For example, single photon avalanche diode detector (SPAD) arrays, avalanche photodetector (APD) arrays, and silicon photomultiplier arrays (SPAs) can be used. The detector size not only sets the resolution by setting the FOV of a single detector, but is also related to the speed and detection sensitivity of each device. State-of-the-art two-dimensional arrays of detectors for LIDAR are already approaching the resolution of VGA cameras and are expected to follow a trend of increasing pixel density similar to that seen in CMOS camera technology. Thus, it is expected that increasingly smaller sizes of detector FOVs, represented by square 204, will be realized over time. For example, an APD array with 264,000 pixels (688(H) x 384(V)) was recently reported in “A 250m Direct Time-of-Flight Ranging System Based on a Synthesis of Sub-Ranging Images and a Vertical Avalanche Photo-Diodes (VAPD) CMOS Image Sensor”, Sensors 2018, 18, 3642.

[0040] Various types of laser arrays can also be used in the LIDAR system according to the present teachings. One example of a laser array is made from vertical cavity surface emitting laser (VCSEL) laser devices. This can include top-emitting VCSELs, bottom-emitting VCSELs, and various types of high power VCSELs. These VCSEL devices can be standalone single emitters or can be part of multiple emitter VCSELs that can be fabricated on a substrate as one or two dimensional arrays. The VCSEL contacts that are energized to generate an optical beam from a particular laser can be individually addressed or energized and / or can be electrically connected together in various configurations to energize a group of VCSELs with a common electrical input signal. One feature of the LIDAR system of the present teachings is a system and method for controlling the energization of one or more VCSEL devices in the array with an appropriate drive signal for the particular LIDAR system application. In some embodiments, the VCSEL array is monolithic and the lasers all share a common substrate. Various common substrate types can be used. For example, the common substrate can be a semiconductor material. The common substrate can also include a ceramic material. In some embodiments, the VCSEL array is a 2D VCSEL array, which is fabricated from a group of one-dimensional (1D) bars, or even from a number of individual dies.

[0041] One feature of the LIDAR system according to the present teachings is that the LIDAR system can provide a controllable field of view for various laser arrays. Some embodiments use a VCSEL array. In some embodiments, the VCSEL is a top-emitting VCSEL. In other embodiments, the VCSEL is a bottom-emitting VCSEL. An individual VCSEL may have a single large emission aperture, or may be formed from two or more subapertures within a larger effective emission diameter. A group of subapertures that form a larger effective emission area is sometimes referred to as a cluster. The subapertures within a cluster can be electrically connected in parallel such that they are electronically activated by a single control signal.

[0042] 2A illustrates a schematic diagram of a 2D monolithic VCSEL array 200 having 256 separate laser emitters 202, each emitter 202 corresponding to a single large aperture used in some embodiments of the LIDAR emitter of the present teachings. Each laser emitter has an emission aperture of diameter a 204. The emission from each single laser emitter 202 substantially fills the entire emission aperture diameter a 204. Thus, each laser emitter generates a laser beam having an initial diameter a equal to the diameter of the emission aperture. The laser emitters are spaced apart at intervals d x 206 and are uniformly spaced horizontally at intervals d y The lasers are uniformly spaced vertically at 208. The overall size of the array as measured from the center of the outermost lasers is spaced horizontally by a distance D x 210, vertically at distance D y 212. The actual chip size is dimension D x 210 and D y 212. In various embodiments, the emitters can produce optical beams having various shapes. For example, elliptical, square, rectangular, and various irregular shapes can be realized. Between the emitters 202 are regions 214, which are gaps that do not have an emitter and therefore do not provide illumination.

[0043] FIG. 2B illustrates a schematic diagram of a 2D monolithic VCSEL array 250 having 256 separate laser emitters 252, each laser emitter 252 having nine subapertures 254, that can be utilized in some embodiments of the LIDAR emitter of the present teachings. Emission from each single laser emitter 252 results in emission from all nine subapertures 254. If one or more of the nine subapertures 254 cannot emit light due to a fabrication anomaly or device failure, the emitter 252 still functions and generates an optical beam, albeit at a lower output power. The output optical beam corresponds to the pattern of the subapertures 254, which can be arranged in a variety of shapes. In the configuration shown, the output beam is nominally square in shape, corresponding to the emitter 252 shape of a 3×3 square array of nine subapertures 254. The laser emitters 252 are spaced apart at intervals d x 256 evenly spaced horizontally, with interval d y The lasers are uniformly spaced vertically at 258. The overall size of the array, measured from the center of the outermost lasers, is spaced horizontally by a distance D x 260, vertically at distance D y 262. The actual chip size is the distance D x 260 and distance D y 214, 264. A variety of array patterns are possible, including regular and irregular arrays. The VCSEL of Figures 2A-B includes areas of the VCSEL die, e.g., regions 214, 264, from which light is not emitted.

[0044] Some embodiments of the present teachings utilize bottom-emitting high-power arrays of VCSELs arranged in regularly spaced rectangular arrays with a single large aperture per laser, such as in the configuration shown in Figure 2A. Other embodiments of the LIDAR system of the present teachings utilize top-emitting or bottom-emitting high-power arrays of VCSELs with an overall light-emitting area comprising subapertures. However, those skilled in the art will understand that the present teachings are not limited to any single configuration of top-emitting and bottom-emitting VCSELs associated with the light-emitting aperture or array spacing or shape.

[0045] One feature of the LIDAR system of the present teachings is that the emitters may not all emit light at the same wavelength. Thus, various emitters in the array can produce light having different wavelengths than other emitters. For example, emitters in one column or row may emit one wavelength, and emitters in alternating columns or rows may emit different wavelengths. A variety of wavelength patterns can be used.

[0046] The use of 2D VCSEL arrays as building blocks for the LIDAR system of the present teachings establishes an emitter platform that allows for small physical sizes for the emitters. For example, a typical 2D array with 256 high-power individual laser emitters can be fabricated on a monolithic chip with dimensions that are approximately 4 mm x 4 mm. The monolithic 2D laser array is then used with emitter optics that are chosen to keep the physical dimensions as small as possible. For example, some embodiments use microlens arrays with a similar size to the monolithic chip. Other embodiments use shared lenses, for example, with a diameter less than 20 mm. Still other embodiments use diffractive optics, for example, with a maximum dimension of 20 mm diameter.

[0047] One feature of the LIDAR system of the present teachings is that the spacing and / or divergence of the optical beams produced by the emitters can be configured to generate an emitter FOV having a desired pattern, shape, or other defined characteristics. For example, the optical beams can be made to overlap or non-overlapping. Selection of the FOV pattern provides control over distance, eye-safety power level, signal-to-noise ratio, and / or resolution, for example, depending on the particular pattern.

[0048] FIG. 3A illustrates a two-dimensional projection of a LIDAR system FOV 300 for operation of an embodiment of a LIDAR system of the present teachings, in which the divergence of 16 laser emitter beams results in gaps between the beams when imaged onto a detector array. The laser emitter FOV is represented by a circle 302, and the detector element FOV is represented by a square 304. In the embodiment shown in FIG. 3A, an FOV having the size of the circle 302 completely covers the square 304 of the nominally four detector element FOV. This optical configuration may result from a highly collimated optical beam. In contrast, an optical configuration resulting in a larger emitter FOV may be achieved by covering more detector elements and reducing the collimation of the optical beam. In an embodiment with a higher collimation of the laser beam, such as the embodiment described in connection with FIG. 3A, the measurement range is improved. This is especially true for smaller targets that may only be partially covered by the laser beam.

[0049] Consider a numerical example of a collimated laser beam for a LIDAR system with a divergence of 10 mrad. At a range of 100 meters, there may be a beam width of 1 meter. For example, a person is only approximately 0.15 meters wide, so a portion of the 1 meter beam does not reach the person and therefore does not contribute to the reflected signal used for measurement. In such a configuration, it is preferred to generate a beam with a smaller divergence and a smaller beam width. However, as illustrated in FIG. 3A, there is a tradeoff between beam divergence and full field of view coverage. In the projection of the LIDAR system FOV 300 shown in FIG. 3A, 16 laser beams are used. In this optical configuration, significant gaps 306 result in the field of view. FIG. 3B illustrates one possible solution to prevent these gaps.

[0050] FIG. 3B illustrates a two-dimensional projection of a LIDAR system FOV 350 for operation of a LIDAR system in which the divergence of the individual laser emitter beams is the same as in FIG. 3A, but the number of laser emitters is increased to 64 beams to eliminate any gaps between the beams when imaged onto the detector array. The laser emitter FOV is represented by a circle 352 and the detector element FOV is represented by a square 354. In this embodiment, the number of laser emitters is increased from 16 to 64, and the lasers are interleaved in a manner that provides complete coverage of the field of view without gaps. Rather, the beam FOV has an overlap 356. The divergence of the optical beams from each emitter is the same as the embodiment of FIG. 3A. One solution for the implementation of the LIDAR system of FIG. 3B may be to have a one-to-one correspondence between each FOV 352 and the individual lasers in the system, so that in this case, 64 individual lasers may be required. In a practical system, the number of lasers may be increased to several thousand or more, and the cost of those lasers and associated electronics may become a concern.

[0051] FIG. 4 illustrates a schematic diagram of an embodiment of an emitter 400 of the present teachings, in which each laser emitter in the array 402 corresponds to a specific projection angle. A lens system 404 collimates and projects the optical beams generated by the emitters in the array 402. The lens system 404 is movable along an axis of relative motion 406. One feature of the present teachings is that limited relative motion can be provided between the laser emitter(s) and the emitter optics to provide movement of the optical beam within the field of view. This movement allows for an additional degree of freedom of control to provide a desired pattern of optical beam. The primary reason for introducing relative motion between the lens system and the laser array is to reduce the number of individual lasers required, with the tradeoff being the additional cost and complexity of incorporating the limited relative motion / actuation. Depending on the system requirements, there is an optimum or at least advantageous cost, performance, and physical size that balances the number of individual lasers and the amount of relative motion required to cover the complete FOV without any gaps in the measurement field of view.

[0052] The array 402 has a dimension D408 at the emission plane. In one relative position between the lens system 404 and the array 402, an emitter 410 at the center of the array 402 generates an optical beam 412 along a centerline 414. The lens system 404 collimates and projects this beam 412 to a central location 416 at the target range. An outer emitter 418 at the edge of the array 402 having the dimension D408 generates an optical beam 420. The lens system 404 collimates and projects this beam 420 to an outer location 422 at the target range. In some embodiments, the projected angle 424 of the outer beam 420 from the edge emitter 418 relative to the central beam 412 from the central emitter 410 is equal to half the field of view (FOV / 2). A controller 426 has an output electrically connected to the inputs of at least some of the emitters in the laser array 402. The controller can select particular individual lasers or groups of lasers within the plurality of lasers to be energized, thus producing a particular laser FOV with a desired pattern of optical beams.

[0053] FIG. 4 also illustrates the basic operating principle of the LIDAR system 400, which uses relative motion between an array of laser emitters 402 and a lens system 404, which act to both collimate the beam for each laser and project each laser at a unique projection angle. In FIG. 4, the direction of relative motion between the laser array 402 and the lens system 404, which is orthogonal to the optical axis 414 of the lens system 404, is indicated by arrow 406. The projection angle is defined by the distance of each laser from the optical axis. Thus, when the lens system 404 and the array 402 are moved relative to each other, the projection angle of each optical beam generated by a particular laser emitter also changes correspondingly. Thus, one feature of the present teachings is that the relative motion between the lens system 404 and the laser array 402 can be used to change the angular resolution for any application, such as to cover gaps in the LIDAR system FOV. Those skilled in the art will appreciate that the optical configuration shown in FIG. 4 is one particular example of the use of relative motion between a laser emitter or laser array and the projection optics. The principle of relative motion is not limited to any particular lens system. In particular, it should be understood that it is not necessary to move all of the lenses in a lens system to generate a change in projection angle for a particular laser. That is, some or all of the lenses in lens system 404 may move. Also, lens system 404 is not limited to a particular number of lenses.

[0054] One feature of the present teachings is that the relative motion of the lens system 404 and the array 402 provides a particular pattern of optical beam FOV that is known to the controller 426. This includes, for example, beam position, beam size, and / or beam overlap. Thus, in some embodiments, the relative motion combined with the control of the pattern of laser firing by the controller 426 can be used to manage the power level of the optical beam at the target range. Specifically, the firing pattern can be used to ensure that a predetermined optical power level is not exceeded in any individual optical beam FOV. In some embodiments, the predetermined power level is the Class 1 eye safety limit. The firing pattern can also be controlled such that a predetermined optical power level is not exceeded in any overlapping optical beam FOV.

[0055] The VCSEL device described in connection with Figures 2A and 2B can be used with a LIDAR system 400 that employs relative motion between an array of laser emitters 402 and a lens system 404. With reference to Figures 2A-2B and 4, if the divergence of the laser is small enough not to result in overlap of the optical beams emitted in the far field, areas of the VCSEL die that do not emit light, e.g., regions 214, 264, can result in gaps in the field of view. Relative motion between the array 402 and lens system 404 described herein can be used to fill those gaps in the field of view.

[0056] 5 illustrates a two-dimensional projection of a LIDAR system FOV 500 of an embodiment of a LIDAR system of the present teachings in which the divergence of the individual laser emitter beams is identical to that for a 2D monolithic VCSEL array with 256 separate laser emitters described in connection with FIG. 2A and relative motion of the lens system and laser array is used to scan in the pattern shown. The emitter FOV pattern in an initial position is shown by a 4×4 array of solid circles 502. The next three positions move the emitter FOV in a square pattern, and the moving square pattern is illustrated by dashed circles. Position 2 is shown as dashed circle 504. Position 3 is shown as dashed circle 504′. Position 4 is shown as dashed circle 504″.

[0057] 4 and 5, the relative motion between the laser array 402 and the lens system 404 traverses a rectangular or square pattern illustrated by arrows 506, 506', 506'', 506''' such that the moving FOV covers the entire LIDAR system FOV using only 16 lasers in a 4x4 array configuration. Note that the relative motion illustrated in this embodiment is required in both the horizontal and vertical directions. The required range of relative motion is equivalent to shifting the laser pattern by half the pitch between any two optical beams generated by the laser emitters. For some embodiments, the actual relative motion required may be approximately half the physical distance between the emitters of the array, which may be several hundred microns.

[0058] Relative motion between the laser array 402 and the lens system 404 can be accomplished through the use of a flexure-based actuator 428. In various embodiments, the actuator 428 comprises various known actuator technologies. For example, actuators are commercially available from several suppliers, including Physik Instrument of Germany. Force to drive the flexure-based actuator can be generated by a variety of electromechanical devices, including piezoelectric motors or voice coil actuators.

[0059] 6A illustrates an embodiment of a LIDAR system 600 of the present teachings that uses two physically separate transmitters 602, 604. Each transmitter 602, 604 includes a VCSEL array 606, 608 with 16 laser emitters. The two transmitters 602, 604 generate optical beams from the laser arrays 606, 608 that are collimated and projected by lens systems 610, 612. The transmitters 602, 604 can generate light at different frequencies. In various embodiments, the lens systems 610, 612 can include one or more lenses and / or other optical elements (not shown). The optical beams from the two transmitters 602, 604 illuminate a target 614 (in this illustration, a car) at a target range 616.

[0060] The light reflected from both emitters 602, 604 is combined at a single receiver 618. The receiver 618 includes a receive optical system 620, which may include one or more lenses in various configurations. The receive optical system 620 may also include other optical elements, such as filters, mirrors, and numerous other optical elements. The receive optical system 620 also includes a detector array 622. The FOVs of both the emitters 602, 604 and the receiver 622 largely overlap.

[0061] Different relative positions of the lens system 610 of the first transmitter 602 and the array 606 in FIG. 6A and different relative positions of the lens system 612 of the second transmitter 604 and the array 608 produce desired controllable positions of the emitter FOV from the two transmitters 602, 604. These controllable positions are produced by actuators 624, 626 that cause relative motion between the arrays 606, 608 and the lens systems 610, 612. In particular, this configuration allows for a combination of changes in the relative motion between the laser arrays 606, 608 and their respective lens systems 610, 612, as described in connection with FIG. 4 and FIG. 5, as well as interleaving of the emitter FOV to provide complete coverage across a desired FOV at one or more target distances. In some embodiments, the interleaved emitter FOVs are generated by optical beams having different wavelengths.

[0062] A controller 628 is connected to the laser arrays 606, 608, the detector array 622, and to the actuators 624, 626. The controller 628 includes outputs that are electrically connected to inputs of the individual lasers and / or groups of lasers in the laser arrays 606, 608 so that the controller can select the particular individual lasers or groups of lasers in the arrays 606, 608 to be energized, thus producing a particular laser FOV having a desired pattern of optical beams. The controller 628 includes outputs that are electrically connected to at least some of the detectors in the detector array 622. Thus, the controller can select the particular detectors to be monitored. The controller 628 also includes a connection to the actuators 624 to control the speed and / or throw and / or direction of the actuators to provide a desired speed and / or displacement and / or direction of relative motion between the arrays 606, 608 and the lens systems 610, 612.

[0063] Figure 6B illustrates a two-dimensional projection of a LIDAR system FOV 630 of an embodiment of the LIDAR system of Figure 6A at one relative position of the lens systems 610, 612 and the laser arrays 606, 608 in the two emitters. With reference to both Figures 6A-6B, this LIDAR system FOV 630 includes an emitter FOV for the first emitter 602 represented by an open circle 632 and an emitter FOV for the second emitter 604 represented by a differently shaded circle 634. In some embodiments, the optical beams that generate the first FOV pattern represented by the open circle 632 are one wavelength and the optical beams that generate the second FOV pattern represented by the shaded circle 634 are a different wavelength.

[0064] The detector FOV in detector array 622 is shown as a square 16x16 grid 636. Also shown is the FOV 638 of the target, which is the automobile 614. The optical beams emitted from the two emitters 602, 604 are interleaved in free space to produce a pattern in the FOV that is an array of circles 632, 634, as shown in Figure 6B.

[0065] Figure 6C illustrates a two-dimensional projection of a LIDAR system FOV 670 of one embodiment of the LIDAR system of Figure 6A at another relative position of the lens systems 610, 612 and the laser arrays 606, 608 within the two emitters 602, 604. Referring to all of Figures 6A-6C, this LIDAR system FOV 670 includes an emitter FOV for one emitter 602 represented by an open circle 672 and an emitter FOV for a second emitter 604 represented by a differently shaded circle 674.

[0066] The detector FOV in the detector array 622 is illustrated as a square 16x16 grid 676. Also shown is the FOV of a target, which is an automobile 678. The optical beams emitted from the two emitters 602, 604 are interleaved in free space to produce a pattern of FOV that is an array of circles 672, 674 shown in FIG. 6C. The relative position of each array 606, 608 in the direction of relative motion 640, 680 with respect to its respective lens system 610, 612 is used to eliminate gaps in the LIDAR system FOV that may otherwise exist if the position is static, i.e., operating only in the position of FIG. 6B or the position illustrated in FIG. 6C. For example, the FOV gap area 642 shown in FIG. 6B is within the covered area 682 shown in FIG. 6C as covered by the FOV of the laser emitter, shown by the circle 684.

[0067] 6A-6C is just one example of how relative motion (controlled relative position) of the lens system and laser array can be used alone or in combination with interleaving and / or the use of different wavelength emitters to produce a desired FOV pattern that provides various performance improvements for the LIDAR system. It should be understood that numerous other combinations of optical free-space interleaving and lens motion exist and / or the use of different optical wavelengths are possible within the scope of the present teachings.

[0068] Most known LIDAR systems use mirrors or motors to scan the FOV with a small number of lasers. The motion is, in some manner, continuous. Continuous motion is accomplished by constantly sweeping the FOV to achieve a desired frame rate. With reference to FIGS. 6A-6C, one aspect of the present teachings is the appropriate selection of the timing of the laser pulses, the frame rate, and the timing and other aspects of the relative motion of the laser array and the lens system. In contrast to known systems, for the LIDAR system illustrated in FIGS. 6A-6C, there is no motion of the lens system, while the laser corresponding to the lens system is pulsed, which allows multiple pulses to be used for averaging / histogramming without significant temporal averaging.

[0069] One example of a method of operation according to the present teachings is as follows. Consider that a LIDAR system operates each laser individually so that the 32 lasers in the laser array 606, 608 of FIG. 6A are not fired at the same time. Also consider that multiple pulses may be used per laser, for example 64 pulses per distance measurement, to generate an average measurement with improved SNR. The time required to scan through each emitter may be 16 lasers x 64 pulses x T, where T is the pulse repetition rate required by the measurement range. For a distance of 200 m, T must be greater than 1.33 μsec. Thus, for this example, the total time to generate a single frame with each emitter is about 1.3 ms. If a frame is generated with each emitter before switching to the next emitter and then back again, an acceptable mode of operation may be to take data with one emitter with its lens system in a steady state while moving the lens system / lens array of the other emitter. And the time required to execute the movement without impacting system performance can be less than 1.3 milliseconds. Flexure-based actuators with hundreds of microns of travel are typically capable of performing such stepwise movements within a few milliseconds, which is within the requirements.

[0070] Note that in practical LIDAR systems, the number of lasers in the array can be much higher, for example 256 as shown in Figures 2A and 2B. Even with fewer averages, such as 16, the time required to obtain a single frame with one emitter is about 5.3 milliseconds. In general, the actuator time is on the order of a few milliseconds. This timing fits a range of LIDAR configurations similar to those described in connection with Figures 6A-6C, depending on the number of lasers per laser array, the number of pulses applied to each laser, the range, and the number of emitters, among other factors.

[0071] 7 illustrates a two-dimensional projection of a LIDAR system FOV 700 of an embodiment of a LIDAR system of the present teachings, where the optical beam FOV 702, 704 is nominally rectangular in shape. The FOV of a single detector pixel is represented by a small square 706 such that the FOV of a single pixel in the detector array is smaller than the laser beam FOV 702, 704. In FIG. 7, the single laser beam FOV 702, 704 is roughly rectangular in shape and when projected onto the detector array, overlaps with tens of pixels in the receiver detector array. In this case, the laser beam can be swept at a rate such that multiple pulses can be obtained with a single pixel without losing a reflected pulse.

[0072] During the movement of the laser beam, the laser optical beam FOV has a start position 708 and a non-overlapping end position 710. For example, pixel 2 712 is located at the rightmost edge of position 1, which is the start position 708 of the beam corresponding to a certain offset between the optical axis of the laser array and the lens system. Pixel 2 712 is at the leftmost edge of position 2, which is the end position 710 of the laser beam. This means that for the majority of the time, pixel 2 receives some reflected light from the laser beam. Even when the laser beam is running, multiple measurements can be taken from this pixel. This allows enough time to obtain the required number of measurements. In this case, the relative movement is typically greater than half the pitch of the laser beam pattern. Pixel 1 716 is located within the start position 708 for the laser FOV 702. The configuration allows certain pixels on the edge, such as pixel 3 714, to be illuminated with more than one laser beam.

[0073] 8 illustrates an embodiment of a LIDAR system emitter 800 of the present teachings in which relative motion of a microlens array 802 is used to vary the projection angle of laser beams 804, 806. An emitter array 808 generates optical beams, such as beams 804, 808, from each laser element 810 in the array 808. For example, in some embodiments, the emitter array 808 is a VCSEL array. Also, in some embodiments, the emitter array 808 is a one-dimensional array, while in other embodiments, the emitter array 808 is a two-dimensional array. In some embodiments, the microlens array 802 is a one-dimensional array, while in other embodiments, the microlens array 802 is a two-dimensional array. The optical beams, such as beams 804, 808, pass through the microlens array 802 and then through additional emitter optics 812 to a target plane 814.

[0074] Relative motion between the microlens array 802 and the emitter array 808 is illustrated by arrow 816. This relative motion is caused by an actuator 817. The relative motion illustrated by arrow 816 is shown as vertical motion in this embodiment, but it should be understood that there can be relative motion in various directions. The direction of relative motion used depends on the desired relative position of the optical beams, e.g., beams 804, 808, at the target plane 814. This relative motion illustrated by arrow 816 can be used to provide a desired FOV of laser FOV to receive FOV as described herein and to meet various performance goals of a LIDAR system that includes a LIDAR emitter 800 that uses a microlens array 802.

[0075] The microlens array 802 has many small lenses 818, with at least one small lens 818 per each laser beam 804, 806 emitted by the corresponding emitter array 808. The dimensions of the small lenses 818 are approximately the same as the pitch of the emitter elements in the emitter array 808. This dimension is typically several hundred microns. In the embodiment illustrated in FIG. 8, the transmitter optics 812 are shown as fixed additional large lenses. The fixed transmitter optics 812 are also used to collimate the laser beams 804, 806, and thus help determine the overall FOV of the transmitter 800. In the configuration shown in this embodiment, only the microlens array 802 is moved to further optimize the speed / response time of the system. Since the microlens array 802 has a small mass, it can be moved quickly. Also, small movements can generate large angular changes.

[0076] For example, a microlens array combined with a 2D VCSEL array as described herein may only need to move about 10 microns to achieve a desired change in projection angle. The microlens array 802 may be physically small, typically only slightly larger than the VCSEL array (meaning that its mass may be kept low), especially if it is formed from a plastic material instead of glass. The small mass and small movement required, which may be about 10 microns, reduces the requirements on required acceleration / force and allows for short actuation times. In such an embodiment, the lens array 802 may be displaced about 10 microns in less than about 50 μs, which may provide additional system flexibility in affecting scan patterns and frame rates. A controller 820 connects to the actuators to provide control of the relative motion and to the laser array 808 to control the firing of specific individual lasers or groups of lasers. Equivalent

[0077] While the applicant's teachings are described in conjunction with various embodiments, it is not intended that the applicant's teachings be limited to such embodiments. Rather, the applicant's teachings encompass various alternatives, modifications, and equivalents that may be made therein without departing from the spirit and scope of the present teachings, as will be appreciated by those skilled in the art.

Claims

1. 1. A light detection and ranging (LIDAR) system comprising: a) a plurality of lasers, each of the plurality of lasers, when energized, generating an optical beam having a field of view (FOV); b) a plurality of detectors formed in an array and positioned in optical paths of optical beams generated by the plurality of lasers, wherein a FOV of at least one of the plurality of optical beams generated by the plurality of lasers overlaps a FOV of at least two of the plurality of detectors; c) a lens system positioned in the optical paths of the optical beams generated by the multiple lasers and in front of the multiple detectors, the lens system collimating and projecting the optical beams generated by the multiple lasers, each of the optical beams emanating from the lens system along a projection angle; and d) an actuator coupled to at least one of the lasers and the lens system, the actuator causing relative movement between the lasers and the lens system in a direction perpendicular to an optical axis of the lens system to cause relative movement between the FOV of the optical beams generated by the lasers and the FOV of the detectors, the relative movement causing a corresponding change in the projection angle; and A LIDAR system comprising:

2. 10. The LIDAR system of claim 1 , wherein at least some of the plurality of lasers are vertical cavity surface emitting lasers.

3. 10. The LIDAR system of claim 1 , wherein at least some of the plurality of lasers comprise two-dimensional monolithic vertical cavity surface emitting lasers.

4. 10. The LIDAR system of claim 1, wherein the multiple lasers are configured to maintain class 1 eye safety within a FOV of each of the multiple lasers.

5. 10. The LIDAR system of claim 1 , wherein at least some of the plurality of lasers are configured to be energized with a matrix addressable controller.

6. 10. The LIDAR system of claim 1, wherein at least some of the plurality of detectors comprise single photon avalanche diode (SPAD) detectors.

7. 10. The LIDAR system of claim 1, wherein at least some of the plurality of detectors comprise silicon photomultiplier (SiPM) detectors.

8. 10. The LIDAR system of claim 1, wherein the actuator comprises a flexure-based actuator.

9. 10. The LIDAR system of claim 1 , wherein the actuator comprises a voice coil.

10. 10. The LIDAR system of claim 1 , wherein the actuator comprises a piezoelectric translator.

11. 10. The LIDAR system of claim 1 , wherein the actuator comprises a shape memory translator.

12. 2. The LIDAR system of claim 1, wherein the actuator is configured to cause relative motion between the multiple lasers and the lens system such that the multiple optical beams move in a two-dimensional pattern.

13. The LIDAR system of claim 12 , wherein the two-dimensional pattern comprises a rectangular pattern.

14. 2. The LIDAR system of claim 1, wherein the actuator is configured such that relative motion between the FOV of optical beams generated by the multiple lasers and the FOV of the multiple detectors changes an angular resolution of the LIDAR system.

15. 2. The LIDAR system of claim 1, wherein the actuator is configured such that relative motion between the FOV of optical beams generated by the multiple lasers and the FOV of the multiple detectors is selected such that overlapping FOVs of the optical beams generated by the multiple lasers cover a full LIDAR system FOV.

16. 2. The LIDAR system of claim 1, wherein the actuator is configured such that relative motion between the FOV of optical beams generated by the multiple lasers and the FOV of the multiple detectors is substantially zero during times when laser pulses are transmitted.

17. 10. The LIDAR system of claim 1, further comprising a controller having a plurality of outputs electrically connected to inputs of at least some of the plurality of lasers, the controller selecting a particular laser within the plurality of lasers to be energized.

18. 20. The LIDAR system of claim 17, wherein the controller further comprises a plurality of inputs electrically connected to a plurality of outputs of at least some of the plurality of detectors, the controller configured to select a particular detector to be monitored.

19. 1. A method for light detection and ranging (LIDAR), comprising: a) energizing selected ones of a plurality of lasers such that each selected one of the lasers generates an optical beam having a field of view (FOV); b) using a lens system to collimate and project the optical beams generated by the selected ones of the plurality of lasers onto a plurality of detectors, each of the optical beams emanating from the lens system along a projection angle, and wherein a FOV of at least one of the plurality of optical beams generated by the plurality of lasers overlaps a FOV of at least two of the plurality of detectors; c) moving the lasers relative to the lens system in a direction perpendicular to an optical axis of the lens system, thereby causing relative motion between the FOV of the optical beams generated by the lasers and the FOV of the detectors, the relative motion causing a corresponding change in the projection angle; and d) monitoring selected ones of the plurality of detectors within the FOV of at least one of the plurality of optical beams generated by the selected ones of the plurality of lasers; A method comprising:

20. 20. The method of claim 19, wherein energizing selected ones of the plurality of lasers comprises firing a pattern of lasers such that a predetermined optical power level is not exceeded within any individual optical beam FOV.

21. 20. The method of claim 19, wherein energizing selected ones of the plurality of lasers includes firing a pattern of lasers such that class 1 eye safety limits are not exceeded within any individual optical beam FOV.

22. 20. The method of claim 19, wherein energizing selected ones of the plurality of lasers comprises firing a pattern of lasers such that a predetermined optical power level is not exceeded within any overlapping optical beam FOV.

23. 20. The method of claim 19, wherein energizing selected ones of the plurality of lasers includes firing patterns of lasers such that class 1 eye safety limits are not exceeded within any overlapping optical beam FOV.

24. 20. The method of claim 19, wherein the relative motion between the plurality of lasers and the lens system is in a direction perpendicular to the optical axis of the lens system.

25. 20. The method of claim 19, wherein the relative motion is approximately half the physical distance between emitters of at least some of the multiple lasers.

26. 20. The method of claim 19, wherein no relative motion between the multiple lasers and the lens system occurs during the time that laser pulses are transmitted.

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