Eye-Safe Long-Range Solid-State LIDAR System

Abstract

A solid-state LIDAR system includes a plurality of lasers, each of which generates a beam with a FOV when excited. A plurality of detectors are located in the optical paths of the beams generated by the plurality of lasers. The FOV of at least one of the plurality of beams generated by the plurality of lasers overlaps with the FOVs of at least two of the plurality of detectors. The controller is configured to generate a bias signal at a plurality of laser control outputs, the bias signal exciting a selected group of the plurality of lasers in a predetermined time sequence, and is configured to detect a predetermined sequence of detector signals generated by the plurality of detectors.

Description

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

[0002] Cross - Reference to Related Applications

[0003] This application is a non - provisional application of U.S. Provisional Patent Application No. 62 / 859,349, titled "Eye - Safe Long - Range Solid - State LIDAR System", filed on Jun. 10, 2019. The entire content of U.S. Provisional Patent Application 62 / 859,349 is incorporated herein by reference. Background of the Invention

[0004] Autonomous, self - driving, and semi - autonomous vehicles use a combination of different sensors and technologies, such as radar, image - recognition cameras, and sonar, to detect and locate surrounding objects. These sensors enable many improvements in driver safety, including collision warning, automatic emergency braking, lane - departure warning, lane - keeping assist, adaptive cruise control, and autonomous driving. Among these sensor technologies, Light Detection and Ranging (LIDAR) systems play a key role in enabling real - time, high - resolution 3D mapping of the surrounding environment.

[0005] Currently, most commercially available LIDAR systems for autonomous vehicles utilize a small number of lasers, combined with some method of mechanically scanning the environment. There is a strong desire for future autonomous vehicles to utilize solid - state semiconductor - based LIDAR systems with high reliability and a wide environmental operating range. Brief Description of the Drawings

[0006] According to preferred and exemplary embodiments, the present teachings, together with their further advantages, are described more specifically in the following detailed description in conjunction with the accompanying drawings. Those skilled in the art will understand that the drawings described below are for illustrative purposes only. The drawings are not necessarily to scale; rather, the emphasis is generally on illustrating the principles of the present teachings. The drawings are not intended to limit the scope of the applicant's teachings in any way.

[0007] Figure 1A A schematic diagram of a known solid - state LIDAR system is shown.

[0008] Figure 1B Shows Figure 1A a two - dimensional projection of the system Field of View (FOV) of the LIDAR system.

[0009] Figure 2A Shows a two - dimensional projection of the LIDAR system FOV of an embodiment of a LIDAR system according to the present teachings.

[0010] Figure 2BShows a detector for a single laser in a two-dimensional projection of the LIDAR system FOV corresponding to an embodiment of a LIDAR system according to the present teachings.

[0011] Figure 2C Shows a two-dimensional projection of the LIDAR system FOV of an embodiment of a LIDAR system according to the present teachings having detector groupings corresponding to the FOV of a single laser providing a particular resolution.

[0012] Figure 3 Shows a perspective view of a schematic diagram of the structure of a known bottom-emitting vertical-cavity surface-emitting laser (VCSEL) used in some embodiments of the LIDAR transmitter of the present teachings.

[0013] Figure 4A Shows a schematic diagram of a 2D monolithic VCSEL array having 256 individual laser emitters, where each emitter corresponds to a single large aperture that can be used in some embodiments of the LIDAR transmitter of the present teachings.

[0014] Figure 4B Shows a schematic diagram of a 2D monolithic VCSEL array having 256 individual laser emitters, where each emitter has nine sub-apertures that can be used in some embodiments of the LIDAR transmitter of the present teachings.

[0015] Figure 5 Shows a graph of an example of the maximum permissible exposure (MPE) in J / cm 2 units calculated based on the IEC-60825 standard at a wavelength of 905 nm.

[0016] Figure 6 Shows a graph of the optical power of a VCSEL laser versus the duty cycle under pulsed conditions.

[0017] Figure 7 Shows a flowchart of an embodiment of a method of operating a LIDAR system capable of pulse averaging, taking into account eye safety and thermal constraints on the duty cycle of individual lasers.

[0018] Figure 8 Shows a two-dimensional projection of the system field of view (FOV) of a LIDAR system configuration for an embodiment in which a row of a detector array is used to obtain multiple measurements while the scene is quasi-static.

[0019] Figure 9 Shows an embodiment of a portion of a LIDAR system of the present teachings, where the transmitter is configured using four VCSEL array components including optics and arranged on a common substrate. Detailed implementation manners

[0020] The present teachings will now be described in more detail with reference to exemplary embodiments of the present teachings as shown in the accompanying drawings. Although the present teachings are described in conjunction with various embodiments and examples, the present teachings are not intended to be limited to these embodiments. On the contrary, as will be understood by those skilled in the art, the present teachings cover various alternatives, modifications, and equivalents. Those skilled in the art who obtain the teachings herein will recognize additional embodiments, modifications, and embodiments within the scope of the present disclosure described herein, as well as other fields of use.

[0021] The phrase "one embodiment" or "an embodiment" as used in the specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present teachings. The phrase "in one embodiment" appearing in various places in the specification does not necessarily all refer to the same embodiment.

[0022] It should be understood that the various steps of the methods of the present teachings can be performed in any order and / or simultaneously, as long as the present teachings remain operable. In addition, it should be understood that the devices and methods of the present teachings can include any number or all of the described embodiments, as long as the present teachings remain operable.

[0023] The present teachings relate to light detection and ranging (LIDAR), which is a remote sensing method that uses lasers to measure the distance (range) to an object. Autonomous vehicles utilize LIDAR systems to generate highly accurate 3D maps of the surrounding environment with high resolution. The systems and methods described herein are intended to provide a solid-state, pulsed time-of-flight (TOF) LIDAR system with a high level of reliability, while also maintaining a long measurement range and low cost.

[0024] The systems and methods described herein for providing a solid-state pulsed TOF LIDAR can also be configured to maintain Class 1 eye safety. A Class 1 eye safety rating means that the system is safe under all normal operating conditions. To maintain Class 1 eye safety, the laser energy or laser optical power cannot exceed the maximum allowable exposure (MPE) level defined by US and international safety standards. However, the measurement range of a LIDAR system strongly depends on the maximum emitted optical pulse energy or power level. Therefore, it is desirable for automotive LIDAR systems to operate as close as possible to the Class 1 MPE limit intentionally.

[0025] Assuming that all LIDAR systems operating at the same wavelength will be subject to the same MPE limit, further range improvements of one LIDAR system relative to another LIDAR system operating at a power level near the MPE power limit must be achieved through various aspects of an innovative optical system. One aspect of this teaching is that a LIDAR system using a highly collimated laser beam where all the energy is emitted into a small FOV can provide a relatively long measurement range compared to a system where the same amount of laser light is dispersed over a wider FOV. That is, the combination of a highly collimated laser beam with a receiver design that allows measurements over a similar small field of view (FOV) will result in a desired ratio of reflected signal power to background light level, which improves the ranging ability.

[0026] A known solid-state 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 solid-state. A flash LIDAR system can illuminate an entire scene with a single illumination event. However, for a LIDAR system operating at the Class 1 eye-safe MPE limit, the wide FOV illuminated by the flash LIDAR significantly limits the measurement range compared to a system where the light from the emission source is highly collimated.

[0027] The pulsed TOF LIDAR system of this teaching uses a collimated transmitter laser beam with an optical power / energy equal to or slightly below the MPE limit for Class 1 eye safety to provide a significant range increase compared to conventional flash LIDAR systems. Additionally, the pulsed TOF LIDAR system of this teaching uses pulse averaging and / or pulse histogramming of multiple laser pulses to improve the signal-to-noise ratio (SNR), which further improves the range. These LIDAR systems employ a very high single-pulse frame rate, far above 100 Hz.

[0028] Figure 1A A schematic diagram of a known solid-state LIDAR system 100 is shown. Figure 1A The system shown does not employ a flash emitter that illuminates the entire system field of view at once. The laser array 102 generates various beam patterns. When the emitter is activated by a control pulse, the beam is emitted from that emitter in the array 102. Sometimes one or more emitters are activated according to a specific sequence. The beams from the lasers in the laser array 102 propagate through a common transmitter optic 104, which projects the beams onto a target 106 at a target plane 110. In this particular example, the target 106 is an automobile 106, but it should be understood that the target can be any object.

[0029] A portion of the light from the incident beam is reflected by the target 106. These portions of the reflected 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 without moving parts. The detector array 114 typically has a smaller number of individual detector elements than the individual lasers of the emitter array 102.

[0030] The measurement resolution of the LIDAR system 100 is not determined by the size of the detector elements in the detector array 114, but by the number of lasers in the emitter array 102 and the collimation of the individual beams. In other words, the resolution is limited by the field of view of each beam. A processor (not shown) in the LIDAR system 100 performs time-of-flight (TOF) measurements that determine the distance to the target 106 based on the beams emitted by the laser array 102 detected at the detector array 114.

[0031] One feature of a LIDAR system according to the present teachings is that the individual lasers and / or groups of lasers in the emitter array 102 can be controlled individually. Each individual emitter in the emitter array can emit independently, where the beam emitted by each laser emitter corresponds to a three-dimensional (3D) projection angle directed at only a portion of the overall system field of view. An example of such a LIDAR system is described in U.S. Patent Publication No. 2017 / 0307736A1, which is assigned to the present assignee. The entire contents of U.S. Patent Publication No. 2017 / 0307736A1 are incorporated herein by reference.

[0032] Another feature of a LIDAR system according to the present teachings is that the detectors and / or groups of detectors in the detector array 114 can also be controlled individually. This independent control of the individual lasers and / or groups of lasers in the emitter array 102 and of the detectors and / or groups of detectors in the detector array 114 provides various desirable operating characteristics, including control of the system field of view, light power levels, and scan patterns.

[0033] Figure 1B A two-dimensional projection of the system field of view 150 of the LIDAR system is shown. Referring Figure 1A to Figure 1A and Figure 1B , the field of view of a single detector in the detector array is represented by the small square 152. The circle 154 shows the illuminated measurement point associated with a single emitter in the emitter laser array 102. Figure 1A A single 3D measurement point in the overall field of view of the LIDAR system is shown as a particular black circle 158, which corresponds to a particular individual laser in the laser array. In Figure 1BIt can also be seen that the measurement point falls within a single detector, where the field of view of the single detector in the detector array 114 has been shown in square 156, which has a hatch pattern for identification. This figure shows that the 3D resolution of some embodiments of the LIDAR system is determined by the number of lasers, because each laser corresponds to a specific angular projection angle, which results in the size of circle 154 at the target range and the relative sizes of circle 154 and square 152 representing the field of view of the individual detector elements.

[0034] Accordingly, by controlling a specific single laser or group of lasers in the transmitter array and / or controlling a single detector or group of detectors in the receiving array, a desired field of view can be established. Different relative fields of view for individual or grouped transmitters and / or individual or grouped detectors can be used to establish various system fields of view. The field of view can be established to produce a specific performance metric and / or combination of performance metrics. These performance metrics include, for example, improved signal-to-noise ratio, longer range or controlled range, eye-safe operating power level, and smaller or larger controllable resolution. Importantly, these performance metrics can be modified during operation to optimize LIDAR system performance.

[0035] The LIDAR system according to this teaching uses an array drive control system that is capable of providing selective control of a specific laser device in the laser device array to illuminate a target according to a desired pattern. Moreover, the LIDAR system according to this teaching can use a detector array that generates detector signals that can be independently processed. Thus, the LIDAR system according to this teaching is characterized by the ability to provide various operating capabilities from the LIDAR system specifically using electronic, non-mechanical, and / or non-moving components, including a fixed array of transmitters and a fixed array of detectors, where shared transmit and receive optics are used to project transmit and receive beams. This LIDAR system configuration can result in a flexible system that is compact in size, reliable in operation, and relatively low in cost.

[0036] The LIDAR system according to this teaching also utilizes a laser array, transmitter optics, receiver optics, and detector array as described in connection with Figure 1A the known systems shown. However, these elements in this teaching are selected and configured such that the two-dimensional projection of the system field of view is different. A feature of this teaching is that the elements are configured such that the field of view of a single transmitter is larger than the field of view of a single detector. Figure 2A An embodiment of the two-dimensional projection of the LIDAR system field of view 200 of an embodiment of the LIDAR system according to this teaching is shown. The system that produces Figure 2A the two-dimensional projection of the LIDAR system field of view 200 shown is one having, for example, as described in connection with Figure 1Aand Figure 1B The projection LIDAR system of the laser array and the emission optics as described for the LIDAR system. However, these elements are spaced apart and arranged to produce the LIDAR system FOV 200 as shown. Specifically, the laser array and the associated emission optics are configured to produce a beam array having a circular FOV of a specific size represented by 16 circles 202 as shown. Various embodiments produce laser beam FOVs of various shapes according to the emitter and the projection optics.

[0037] Figure 2A The LIDAR system FOV 200 shown is produced by a 4×4 (16) laser array. The divergence / collimation of the lasers has been selected such that each beam has only enough overlap so that there are no "gaps" in the field of view. That is, the circles 202 overlap and form a 4×4 array. The detector array provides an array of square FOVs of a specific size represented by 256 squares 204. A single detector region represented by a square 204 is sometimes referred to as a pixel. It can be seen that there are 16×16 (256) detectors that actually continuously cover the entire array. It should be understood that the number of lasers and detectors and the specific size and shape of the FOVs of the emitter and detector elements are chosen to illustrate the features of this teaching and do not necessarily represent an actual system.

[0038] In Figure 2A an embodiment of the LIDAR system, the number of detectors (256) exceeds the number of lasers (16). This embodiment represents an important use case of the LIDAR system according to this teaching, where the FOV of the laser emitter represented by the circles 202 covers the FOVs of multiple detectors represented by the squares 204.

[0039] A variety of detector technologies are used to construct 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 (SPA) can be used. The detector size not only sets the resolution by setting the FOV of individual detectors, but also relates to the speed and detection sensitivity of each device. Two-dimensional arrays of prior art detectors for LIDAR have approached the resolution of VGA cameras and are expected to follow a trend similar to CMOS camera technology of increasing pixel density. Thus, over time, it is desirable to achieve increasingly smaller sizes of the detector FOV represented by square 204. For example, an APD array with 264,000 pixels (688(H)×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] Figure 2B A detector indicating a single laser in a two-dimensional projection of a system FOV corresponding to an embodiment of a LIDAR system 250 according to the present teachings. Similar to Figure 2A the LIDAR system FOV 200 shown in, the single laser FOV is represented by circle 202, and the single detector is represented by square 204. The laser of interest is excited by a controller to illuminate the FOV represented by a particular circle 252. The controller generates a bias signal that excites the desired one or more lasers at the desired time. The detector FOV that overlaps at least some portion of the laser beam FOV represented by circle 252 is within the shaded region 254 in the system FOV. In this particular configuration, for a single laser beam FOV 252, a detector region 254 including 32 individual detector FOVs is achieved. Each detector FOV in the detector region 254 has a FOV associated with the small square 204. Note that in various embodiments, the detector region 254 is not necessarily square or rectangular. The shape of region 254 depends on the detector shape and the laser beam profile, either of which can be any shape (circular, square, or other shape).

[0041] The controller selects a group of one or more detectors in region 254 that fall within the laser beam FOV 252 of the selected laser. Signals from the selected group of detectors are detected simultaneously, and the detected signals are provided to the controller and then processed to generate a single measurement pulse. For long-range operation, including operation at the longest specified range of a LIDAR system, the number of pixels (i.e., individual detectors) used to generate the measurement pulse can be selected to maximize the SNR at the expense of resolution. For example, the optimal SNR can correspond to the measurement result obtained by summing or combining in some way the received signals from all detectors in the highlighted region 254 in Figure 2B That is, multiple consecutive detectors that fall within the FOV 252 of the selected laser can be selected. In some embodiments, only those detectors that are fully illuminated by the light in the FOV 252 of the laser are selected. In this way, the noise from detectors that are not fully illuminated does not accumulate. Alternatively, a smaller subset of detectors can be selected. For example, in some configurations in accordance with the present teachings, the power from the laser is not uniformly distributed across the beam profile. In these configurations, a subset of detectors that matches the profile of the beam can be used, thus selecting detectors that receive higher-intensity incident light.

[0042] At certain ranges, instead of combining pixel signals to maximize the SNR for the longest measurement range, it may be desirable to produce a higher-resolution image. For example, at close ranges, each pixel or a smaller set of pixels can be measured individually to provide a higher-resolution image of the scene. In these embodiments, multiple detectors that provide a detector FOV of a particular size or shape are selected to facilitate generating a particular measurement pulse with a particular resolution at the target range.

[0043] Figure 2C A two-dimensional projection of the LIDAR system FOV 270 of an embodiment of a LIDAR system in accordance with the present teachings is shown, the LIDAR system having detectors grouped for a single laser FOV 286 that provide a particular resolution. With Figure 2ASimilarly, the FOV of a single laser is represented by circle 202, and a single detector representing a single pixel in this configuration is represented by square 204. In this embodiment, each of the seven groups 272, 274, 276, 278, 280, 282, 284 of four pixels is used for the FOV of a single laser beam represented by circle 286. The seven groups 272, 274, 276, 278, 280, 282, 284 of four pixels can each be individually selected to contribute to a particular measurement pulse. Each measurement pulse will result in a resolution based on the size of the particular group 272, 274, 276, 278, 280, 282, 284. Thus, in this case, seven measurement results can be obtained within the illumination FOV (circle 286), each having a resolution less than the illumination laser spot FOV (circle 286). Thus, by selecting the particular number and shape of detectors, various resolutions can be provided. For example, using only two pixels arranged vertically, rather than the four pixels as shown in the groups 272, 274, 276, 278, 280, 282, 284, will result in the same resolution in the vertical dimension and half the resolution in the horizontal dimension. Similarly, using only two pixels arranged horizontally rather than four pixels will result in the same resolution in the horizontal dimension as the groups 272, 274, 276, 278, 280, 282, 284 and half the resolution in the vertical dimension. The various groupings described are merely examples. The detectors are selected to provide group sizes and shapes to provide the desired resolution for a particular measurement result. Figure 2C Using only two pixels arranged vertically, rather than the four pixels as shown in the groups 272, 274, 276, 278, 280, 282, 284, will result in the same resolution in the vertical dimension and half the resolution in the horizontal dimension. Similarly, using only two pixels arranged horizontally rather than four pixels will result in the same resolution in the horizontal dimension as the groups 272, 274, 276, 278, 280, 282, 284 and half the resolution in the vertical dimension. The various groupings described are merely examples. The detectors are selected to provide group sizes and shapes to provide the desired resolution for a particular measurement result.

[0044] Figure 3 A perspective view showing a schematic diagram of the structure of a known bottom-emitting vertical cavity surface emitting laser (VCSEL) 300 used in some embodiments of the LIDAR transmitter of the present teachings is shown. The area of the emission aperture 302 of the VCSEL 300 generally ranges from a diameter of a few microns for operation at mW power to a diameter of 100 microns or greater for operation at 100 mW and greater CW power. The VCSEL 300 is fabricated on a substrate 304, which can be, for example, GaAs or a variety of other semiconductor materials.

[0045] The n-type distributed Bragg reflector (DBR) layer 306 is located on the substrate. The active region 308 is constructed on the n-type DBR layer 306, and then holes 310 can be formed in the oxide material. Then, a p-type DBR layer 312 is grown on the active region. Generally, the p-type DBR layer 312 is highly reflective, while the n-type DBR layer 306 is partially reflective, resulting in light output 314 from the bottom, substrate side of the layer structure. In the device shown, the active region 308, the oxide holes 310, and the p-type DBR layer 312 form a mesa structure. The top contact 316 and the bottom contact 318 are used to supply current to the active region to generate output light. The oxide holes 310 provide current confinement for the active region 308. The top contact 316 is p-type, and the bottom contact 318 is n-type.

[0046] An emission hole 302 is formed in the bottom contact 318 to allow the output light 314 to emit from the bottom, substrate side of the bottom-emitting VCSEL 300. Note that Figure 3 only one emission hole 302 is shown because Figure 3 only one emitter of a multi-emitter VCSEL array is shown. This type of VCSEL can be a stand-alone single emitter or can be part of a multi-emitter VCSEL that can be fabricated as a one-dimensional or two-dimensional array on the substrate 304. The VCSEL contacts 316, 318 can be individually addressed and / or can be electrically connected together in various configurations to address groups of VCSELs with a common electrical input signal. One feature of the present teachings is a system and method for controlling the excitation of one or more VCSEL 300 devices in an array using an appropriate drive signal for a particular LIDAR system application.

[0047] Various embodiments of the present teachings use various known VCSEL laser devices, including top-emitting VCSELs, bottom-emitting VCSELs, and various types of high-power VCSELs.

[0048] 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, and the 2D VCSEL array is assembled from a set of 1D stripes or even from multiple individual die.

[0049] One feature of LIDAR systems in accordance with the present teachings is that they can provide a controllable field of view for various laser arrays. Some embodiments use VCSEL arrays. In some embodiments, the VCSELs are top-emitting VCSELs. In other embodiments, the VCSELs are bottom-emitting VCSELs. A single VCSEL can have a single large emission aperture, or a single VCSEL can be formed by two or more sub-apertures within a larger effective emission aperture. A group of sub-apertures forming a larger effective emission area is sometimes referred to as a cluster. The sub-apertures in a cluster can be electrically connected in parallel such that they are electronically activated by a single control signal.

[0050] Figure 4A A schematic illustration of a 2D monolithic VCSEL array 400 with 256 individual laser emitters 402 used in some embodiments of a LIDAR transmitter in accordance with the present teachings is shown, where each emitter 402 corresponds to a single large aperture. Each laser emitter has an emission aperture with a diameter of a 404. The emission from each individual laser emitter 402 substantially fills the entire emission aperture diameter a 404. Thus, each laser emitter produces a laser beam with an initial diameter “a” 404 that is equal to the diameter of the emission aperture. The laser emitters are uniformly spaced apart with a pitch dx 406 in the horizontal direction and a pitch dy 408 in the vertical direction. The total size of the array measured from the centers of the outermost lasers is a distance Dx 410 in the horizontal direction and a distance Dy 412 in the vertical direction. The actual chip size will be slightly larger than the dimensions Dx 410 and Dy 412. In various embodiments, the emitters can produce beams with various shapes. For example, elliptical, square, rectangular, and various exotic shapes can be achieved.

[0051] Figure 4BFIG. 0 shows a schematic diagram of a 2D monolithic VCSEL array 450 with 256 individual laser emitters 452 that can be used in some embodiments of the LIDAR emitter of the present teachings, where each laser emitter 452 has nine sub-apertures 454. Emission from each individual laser emitter 452 results in emission from all nine sub-apertures 454. In the case where one or more of the nine sub-apertures 454 do not emit light due to manufacturing anomalies or device failures, the emitter 452 still operates and produces a beam, although at a lower output power. The output beam will correspond to the pattern of the sub-apertures 454, and the sub-apertures 454 can be arranged in various shapes. In the illustrated structure, the output beam is nominally square, corresponding to the shape of the emitter 452 in a 3×3 square array of nine sub-apertures 454. The laser emitters 452 are uniformly spaced apart in the horizontal direction by a pitch dx 456 and in the vertical direction by a pitch dy 458. The total size of the array measured from the center of the outermost lasers is a distance Dx 560 in the horizontal direction and a distance Dy 462 in the vertical direction. The actual chip size will be slightly larger than the distance Dx 460 and the distance Dy 462. Various array patterns (including regular and irregular arrays) are possible. Figure 4A - Figure 4B The VCSELs of Figure 4A - Figure 4B include regions of the VCSEL chip that do not emit light, such as regions 414, 464.

[0052] Some embodiments of the present teachings utilize a bottom-emitting high-power VCSEL array with a single large aperture per laser, and are configured as a regularly spaced rectangular array, such as Figure 4A the configuration shown. Other embodiments of the present teachings utilize a top-emitting or bottom-emitting high-power VCSEL array that has a total emission area that includes sub-apertures. However, those skilled in the art will understand that the present teachings are not limited to any single configuration of top and bottom-emitting VCSELs, associated emission windows, or array spacing or shape.

[0053] One feature of the LIDAR systems of the present teachings is that the emitters may not all emit light at the same wavelength. The wafer production process for producing VCSELs typically results in each wafer having a center wavelength, and the distribution of wavelengths across the wafer is within a few nanometers of the center value. Thus, LIDAR systems that use multiple wavelengths will typically use multiple individual die, each having a specific wavelength, and then arrange these die with an optical system to produce the desired far-field projection pattern. Two common types of far-field projection patterns are side-by-side and interleaved. In a side-by-side far-field projection pattern, the FOV is divided into regions of different wavelengths that are adjacent to each other, where only the edges overlap, while in an interleaved pattern, most of the FOV contains more than two wavelengths.

[0054] Using a 2D VCSEL array as a building block of the LIDAR system of the present teachings establishes a transmitter platform that allows for a transmitter of small physical size. For example, a typical 2D array with 256 high-power independent laser transmitters can be fabricated on a monolithic chip having dimensions of approximately 4 mm × 4 mm. The monolithic 2D laser array is then used in conjunction with emission optics selected to keep the physical size as small as possible. For example, some embodiments use a microlens array having dimensions similar to that of the monolithic chip. Other embodiments use a shared lens having a diameter, for example, of less than 20 mm. Still other embodiments use diffractive optics having a maximum dimension of, for example, 20 mm in diameter.

[0055] One feature of the LIDAR system of the present teachings is that the spacing and / or divergence of the beams generated by the transmitter can be configured to generate a transmitter FOV having a desired pattern, shape, or other specified characteristics. For example, the beams can be made to overlap or not overlap. The choice of FOV pattern provides control over, for example, range, eye-safe power level, signal-to-noise ratio, and / or resolution, depending on the particular pattern.

[0056] The solid-state LIDAR system of the present teachings complies with Class 1 eye safety limits. Figure 5 A graph 500 showing an example of the Class 1 permitted MPE in J / cm 2 units calculated at a wavelength of 905 nm based on the IEC-60825 standard is shown. It should be understood that this is merely a schematic calculation. The MPE is based on many considerations, and this example is for illustrative purposes. Figure 5 The values shown therein will vary based on the specific details of the exact lasers and optics used. However, from Figure 5 it can be seen that the MPE limit varies with exposure duration. As a result, the length of time the laser is energized will affect how much peak power can be used. The critical time period corresponding to a TOF system is shown in the figure as the highlighted region from 1 microsecond to 3 microseconds. This corresponds respectively to the time it takes for a laser pulse to propagate out to a target at 150 m and 450 m and return. Clearly, a single laser pulse with an MPE-limited optical power is thus limited by the eye-safe exposure duration. A single pulse at the MPE limit can only be emitted once every 5 microseconds because there is little relative motion in such a short time to change the relationship between the laser and the measurement aperture located at a distance of 100 mm as defined by the eye safety standard. In the case of a LIDAR system where pulse averaging is desired, when a single laser operates at the MPE limit of Class 1, this limits the emission rate of a single laser to >5 microseconds.

[0057] One feature of the present teachings is the positioning of one or more emitter arrays, emission optics, reception optics, and detector arrays relative to each other such that the emission pattern of the lasers can be controlled to support multi-pulse averaging and / or provide a histogram of the measurement pulses. In some embodiments, a set of lasers is selected and the set of lasers is excited in sequence. The sequence is then repeated a number of times such that the measurement pulses obtained from each laser can be averaged over the number of repetitions. For example, a sequence such as A-B-C-D-A-B-C-D can be repeated up to N times, where each letter is a particular emitter in a set of four emitters.

[0058] In some embodiments, the sequence is selected such that the optical power from the LIDAR system does not exceed the eye safety limit. In some embodiments, for example, each emitter is excited to produce an optical power at or near the MPE. Thus, if the beams of two or more laser emitters overlap, the MPE may be exceeded. In such cases, the emission sequence of the laser pattern is such that two lasers with overlapping FOVs that would exceed the MPE are not excited simultaneously. For example, this may mean that two lasers with overlapping FOVs are emitted at different points in the sequence. However, lasers with non-overlapping FOVs can be emitted simultaneously.

[0059] The physical architecture (i.e., the specific locations of the laser arrays, emission optics, reception optics, and detector arrays) is configured to support specific performance goals. For example, in some embodiments, the individual lasers in the sequence are physically located in separate arrays. For example, in the above example, the lasers represented as A and C are in one array and the lasers represented as B and D are in different arrays. In some embodiments, the detector array shape and configuration impose constraints on the sequence and / or the repeat value. For example, some detector arrays work best if the sequence measurements are limited to a particular row or column in a set of measurement data. This is because the detector array may not be able to switch or reconfigure detection events quickly enough to support arbitrary geometries.

[0060] One feature of the present teachings is that the physical structure of the LIDAR and the control of these elements can provide control over the maximum range and the accuracy of the range measurements. Figure 6FIG. 600 is shown, which shows an important relationship between the peak optical power and the duty cycle of a laser operating with very short duration pulses, such as in a LIDAR system. FIG. 600 shows the peak optical power of a VCSEL emitter as a function of the pulsed bias current. To maximize range and minimize range ambiguity, the duration of the laser pulses in a pulsed TOF LIDAR system is typically less than 10 nanoseconds. The physical properties of the laser are such that there is no time to dissipate heat during such short duration pulses, so higher optical power is obtained with a lower duty cycle. The typical behavior is shown in FIG. 600, where it can be seen that the linear part of the CW curve can extend further for longer duty cycles. A LIDAR system can operate with a duty cycle <0.1% to obtain the maximum peak power from the laser. For a 10 nanosecond pulse duration, a 0.1% duty cycle would correspond to a 10 microsecond duration between pulses.

[0061] Thus, the laser peak power, pulse duration, and pulse duty cycle are limited based on eye safety and heat dissipation considerations. Range and range ambiguity are another consideration. Clearly, to operate the laser at the maximum possible power, eye safety and pulse duty cycle can impose constraints on the time between pulses, and that time may be longer than desired for the range of the system. For example, a LIDAR system with a maximum range of only 150 meters based on TOF can emit one pulse per microsecond without ambiguity. However, eye safety and duty cycle constraints may limit the laser to emitting only every 5 to 10 microseconds. To be able to average multiple pulses, the pulses should be close in time. If an object is traveling at a relative speed of 50 meters per second, its distance will change by 5 millimeters in 100 microseconds. Therefore, to not blur the target distance and the target itself, the system should complete all pulse averaging where the scene is quasi-stable and the total time between all pulses is on the order of 100 microseconds. Of course, there are interactions between these various constraints. However, it is clear that based on a specific desired performance, a specific physical architecture and control scheme can be combined to achieve that performance.

[0062] The solid-state LIDAR system of the present teachings maximizes the possible measurement rate and achieves pulse averaging by following the Figure 7 flowchart shown. A method is used for forming a group or subset of lasers, where the emission rate of each individual laser is constrained by eye safety and / or pulse duty cycle, but the lasers are emitted sequentially within the group to maintain the overall desired measurement rate. For example, if the desired measurement rate is 1 microsecond and the emission of a single laser is limited to 5 microseconds, a group of 5 lasers (A, B, C, D, E) is formed, and the lasers are emitted in sequence A - B - C - D - E, and the sequence is repeated for the desired number of pulses to be averaged.

[0063] Figure 7 FIG. 700 is a flow chart of a method for operating a LIDAR system that implements pulse averaging taking into account eye safety and thermal constraints on the duty cycle of individual lasers. In a first step 702, the system is initialized. This initialization can include, for example, using preset information and / or test measurement results to help configure the control scheme. Control scheme configuration includes, for example, determining constraints on laser power, pulse duration duty cycle, individual laser and detector positions, detector sensitivity, crosstalk, and / or beam profile. This information is then used to inform subsequent steps of the method. Once the system is initialized, in step two 704, the laser emission pattern and emission rate are determined. In some embodiments, a sequence of detection events (detector position, detection duration, and duty cycle) and a measurement method (averaging repetition time, etc.) are established. In Figure 7 an embodiment, in step three 706, the system selects a group of lasers from the overall list of lasers that meet the desired constraints on the emission rate of individual lasers. In step four 708, the detector event sequence is also determined and / or a specific number of pulses to be averaged is established.

[0064] The system then proceeds to fire each laser within the group individually and receive and store the return signal for the desired maximum range until all lasers within the group have been fired once. Specifically, in step five 710, each laser from the selected group is fired in the selected sequence, and the detection events from each laser firing are recorded. In step six 712, the controller determines whether the number of pulses to be averaged has been reached. If not, the system returns to step five 710. The firing sequence is repeated until it is determined in step six 712 that the desired number of pulses to be averaged has been reached. The recorded data from each firing can be averaged or stored as a sequence histogram. In step seven 714, signal processing is performed in a processor that calculates the TOF based on the average value and / or histogram of the data from each individual laser. In step eight 716, the processor determines and stores and / or reports 3D point data in the form of TOF, amplitude, and error. In step nine 718, the system decides whether to continue back to step three 706 and move to a new group or end. If not continuing, the method ends in step ten 720. Completion of all lasers in the emission list represents completion of a full frame.

[0065] This is only one possible flow chart and is presented only as an example. Additional operational flows are also possible. For example, in some systems, the data from each pulse can not only be recorded but also transmitted externally, and / or intermediate TOF information can be calculated according to system requirements. Instead of simple pulse averaging or histogramming of the data, error processing, pulse coding, and / or more complex digital signal processing are possible.

[0066] Figure 8 shows additional illustrations of the process outlined in Figure 7 . In particular, Figure 8 shows a two-dimensional projection of the system field of view (FOV) 800 of a LIDAR system configuration for one embodiment, where a one-row detector array is used to obtain multiple measurements while the scene is quasi-static. In this embodiment, there are five lasers that overlap to cover all ten detectors. There are five corresponding laser FOVs 802, 802’, 802’’, 802’’’, and 802’’’’. There are ten detector FOVs 804, 804’, 804’’, 804’’’, 804’’’’, 804’’’’’, 804’’’’’’, 804’’’’’’’, 804’’’’’’’’, and 804’’’’’’’’’.

[0067] This configuration utilizes the emission sequence of the lasers denoted by the letters (A, B, C, D, E). Thus, the laser that generates FOV 802 emits, then the laser that generates FOV 802’ emits, then the laser that generates FOV 802’’ emits, then the laser that generates FOV 802’’’ emits, then the laser that generates FOV 802’’’’ emits. In each case, the FOV of one laser irradiates the FOVs of two detectors within the corresponding row. In other words, in one example, FOV 802 irradiates detector FOVs 804, 804’. To meet eye safety and / or thermal constraints, a specific sequence for emitting these lasers may be required, e.g., A then C, then E, then B, then D. The sequence A-C-E-B-D is then repeated to obtain multiple measurements for averaging or histogramming to improve the SNR. Note that in this sequence, no set of detectors is adjacent to the previous set of detectors, which means there are gaps in the FOVs of the corresponding lasers. For example, the detectors labeled A that generate detector FOVs 804, 804’ are not adjacent to the detectors labeled C that generate detector FOVs 804’’’, 804’’’’. This may be beneficial for eye safety by ensuring no FOV overlap between the emitted laser beams.

[0068] In some specific embodiments, the duration during which measurements are obtained is on the order of 100 microseconds, such that the scene is quasi-static and no object in the scene can move more than a few millimeters in position. Figure 8 The other detector rows in the LIDAR system in Figure 8 will operate in a similar manner to measure the entire field of view. The embodiments in

[0069] Figure 9 An embodiment showing a portion of the LIDAR system 900 of the present teachings is presented, where the transmitter 902 is configured using four VCSEL array components 904, 906, 908, 910 that include optics and are arranged on a common substrate 912. The four VCSEL array components 904, 906, 908, 910, each including corresponding optics, are arranged in a square pattern on the common substrate 912. In this embodiment, each VCSEL in the VCSEL array components 904, 906, 908, 910 has 32 individually addressable lasers. The VCSEL array components 904, 906, 908, 910 are labeled as Component 1, 904, Component 2, 906, Component 3, 908, and Component 4, 910. The individual beams of the individual lasers in the VCSEL arrays associated with each VCSEL array component 904, 906, 908, 910 are projected into the far field such that they are interleaved in a set pattern determined by the pitch of the elements in the array, by the pitch of the VCSEL arrays, and by the projection optics.

[0070] The laser beam pattern in the far field 914 shows how the beams from the individual lasers in the various arrays appear. This pattern in the far field 914 is the pattern of the laser beam FOV as described herein. The FOV of the lasers from Component 1, 904 is represented by 1 as shown by the square 916 in the FOV. The FOV of the lasers from Component 2, 906 is represented by 2 as shown by the square 918 in the FOV. The FOV of the lasers from Component 3, 908 is represented by 3 as shown by the square 920 in the FOV. The FOV of the lasers from Component 4, 910 is represented by 4 as shown by the square 922 in the FOV. Although the FOV is illustrated as a square, its shape can be based on various shapes such as the transmitter shape and the projection optics.

[0071] In various embodiments, the laser beam patterns from each array can be arranged in a variety of patterns. In an embodiment of the LIDAR system 900, the FOVs 916, 922 of the laser arrays (1, 4) 904, 910 overlap in free space, the FOVs 918, 920 of the laser arrays (2, 3) 906, 908 also overlap, and the two sets of patterns (1, 4) 924 and (2, 3) 926 are arranged side by side. The illustration of the LIDAR system 900 is not to scale and does not show all components, but is intended to illustrate the concept of the generation of the laser FOV patterns at the target range. Thus, the far-field pattern 914 at a particular target plane is not drawn to scale and will vary as a function of distance. In operation, each individual laser in each array component 904, 906, 908, 910 can be independently emitted as described herein. In various embodiments, the emission rate can be determined by meeting the desired eye safety threshold and / or thermal considerations.

[0072] The wavelengths of the VCEL arrays in the array components 904, 906, 908, 910 are not necessarily the same. In some embodiments, the wavelengths of the lasers in the arrays (1, 4) 904, 910 and (2, 3) 906, 908 can be different wavelengths, thereby producing a side-by-side pattern. This wavelength arrangement may be beneficial in order to minimize the likelihood of optical crosstalk between the two sets of lasers at the receiver (not shown). Alternatively, optionally, the lasers in the arrays (1, 2) 904, 906 can be the same wavelength, while the lasers in the arrays (3, 4) 908, 910 are different wavelengths, thereby producing an interleaved pattern. This wavelength arrangement will allow for a certain level of redundancy and parallel operation across the entire field of view. By arranging the array components 904, 906, 908, 910 in physically separated positions on the substrate 912, there is greater flexibility in meeting Class 1 eye safety while maintaining a high pulse emission rate, since the beams from each array do not overlap in the near field.

[0073] Equivalents

[0074] Although the applicant's teachings are described in connection with various embodiments, the applicant's teachings are not intended to be limited to these embodiments. Instead, as will be understood by those skilled in the art, the applicant's teachings include various alternatives, modifications, and equivalents, which can be made therein without departing from the spirit and scope of the teachings.

Claims

1. A solid-state light detection and ranging LIDAR system, comprising: a) a plurality of lasers, each of the plurality of lasers generating a beam with a field of view (FOV) when excited; b) a plurality of detectors located in the optical paths of the beams generated by the plurality of lasers, each of the plurality of detectors having a detector signal output, wherein the FOV of at least one of the plurality of beams generated by the plurality of lasers is greater than the FOV of at least one of the plurality of detectors and overlaps the FOVs of at least two of the plurality of detectors; and c) a controller having a plurality of laser control outputs and a plurality of detector inputs, each of the plurality of laser control outputs being electrically connected to a bias input of one of the plurality of lasers, and each of the plurality of detector inputs being electrically connected to a detector signal output of one of the plurality of detectors, the controller being configured to generate a bias signal at the plurality of laser control outputs, the bias signal exciting a selected group of the plurality of lasers in a predetermined time sequence, the predetermined time sequence being selected to maintain eye safety conditions, and the controller being configured to detect a predetermined sequence of detector signals generated by the plurality of detectors, the predetermined sequence of detector signals being selected to provide a desired measurement resolution.

2. The solid-state LIDAR system according to claim 1, wherein At least some of the plurality of lasers include vertical cavity surface emitting lasers.

3. The solid-state LIDAR system according to claim 1, wherein, At least some of the plurality of lasers emit lasers of different wavelengths.

4. The solid-state LIDAR system according to claim 1, wherein The plurality of lasers includes a two-dimensional laser array.

5. The solid-state LIDAR system according to claim 4, wherein, One row in the two-dimensional laser array emits a laser of one wavelength when excited by the controller, and another row in the two-dimensional laser array emits a laser of a second wavelength when excited by the controller.

6. The solid-state LIDAR system according to claim 4, wherein, The selected group of the plurality of lasers includes rows of the two-dimensional array.

7. The solid-state LIDAR system according to claim 4, wherein, The selected group of the plurality of lasers includes columns of the two-dimensional array.

8. The solid-state LIDAR system according to claim 1, wherein The plurality of detectors includes a two-dimensional detector array.

9. The solid-state LIDAR system according to claim 8, wherein, The controller is configured to sequentially sample detector signals from one row of the two-dimensional detector array.

10. The solid-state LIDAR system according to claim 8, wherein, The controller is configured to sequentially sample detector signals from one column of the two-dimensional detector array.

11. The solid-state LIDAR system according to claim 1, wherein, The controller is further configured to repeat the generation of the bias signal at the plurality of laser control outputs, the bias signal exciting the selected group of the plurality of lasers multiple times in the predetermined time sequence.

12. The solid-state LIDAR system according to claim 1, wherein, The controller is configured to detect a predetermined sequence of detector signals generated by the plurality of detectors in a sequence repeated multiple times.

13. The solid-state LIDAR system according to claim 1, wherein The controller is configured to generate a bias signal at the plurality of laser control outputs, the bias signal exciting the selected group of the plurality of lasers with different wavelengths in the predetermined time sequence.

14. The solid-state LIDAR system according to claim 1, wherein, The controller is configured to generate a bias signal at the plurality of laser control outputs, the bias signal exciting the selected group of the plurality of lasers to emit light in a predetermined pattern.

15. The solid-state LIDAR system according to claim 14, wherein, The controller is configured to detect a predetermined sequence of detector signals corresponding to the predetermined pattern of light emitted from the plurality of lasers, generated by the plurality of detectors.

16. The solid-state LIDAR system according to claim 1, wherein, The controller is configured to generate a bias signal at the plurality of laser control outputs, the bias signal exciting a selected group of the plurality of lasers to emit light in a predetermined pattern that maintains a Class 1 eye-safe optical power level in the predetermined pattern.

17. The solid-state LIDAR system according to claim 1, wherein, The controller is configured to generate a bias signal at the plurality of laser control outputs, the bias signal exciting a selected group of the plurality of lasers to maintain a predetermined heat dissipation.

18. The solid-state LIDAR system according to claim 1, wherein, The controller is configured to detect a predetermined sequence of detector signals generated by detectors located in an area illuminated by a single laser beam FOV.

19. The solid-state LIDAR system according to claim 18, wherein, The detectors located in the area illuminated by the single laser beam FOV include all detectors illuminated by the single laser beam FOV.

20. The solid-state LIDAR system according to claim 18, wherein, The detectors located in the area illuminated by the single laser beam FOV include a subset of the detectors illuminated by the single laser beam FOV.

21. The solid-state LIDAR system according to claim 20, wherein, The subset of detectors includes detectors that form a shape providing a desired angular resolution for a particular measurement.

22. A method of an optical detection and ranging LIDAR, the method comprising: a) exciting a selected group of a plurality of lasers in a predetermined time sequence to generate a beam having a field of view (FOV), wherein the predetermined time sequence is selected to maintain eye-safe conditions; and b) detecting, with a plurality of detectors in a predetermined time sequence, the beam generated by the selected group of the plurality of lasers, wherein the FOV of the beam generated by the selected group of the plurality of lasers is greater than the FOV of at least one of the plurality of detectors and overlaps the FOVs of at least two of the plurality of detectors, and wherein the number and positions of the plurality of detectors are selected to provide a desired measurement resolution.

23. The method according to claim 22, wherein, The selected group of the plurality of lasers is selected to limit the operating temperature of the plurality of lasers to below a predetermined temperature.

24. The method according to claim 22, wherein, Exciting the selected group of the plurality of lasers includes exciting at least some of the plurality of lasers at different emission wavelengths.

25. The method according to claim 22, wherein Exciting the selected group of the plurality of lasers includes exciting a two-dimensional laser array.

26. The method according to claim 25, wherein Lasers in the first row of the two-dimensional laser array emit laser light of a first wavelength, and lasers in the second row of the two-dimensional laser array emit light of a wavelength different from the first wavelength.

27. The method according to claim 22, wherein, Exciting the selected group of the plurality of lasers includes exciting a subset of the two-dimensional laser array.

28. The method according to claim 22, wherein Exciting the selected group of the plurality of lasers includes exciting a row in the two-dimensional laser array.

29. The method according to claim 22, wherein, Exciting the selected group of the plurality of lasers includes exciting a column in the two-dimensional laser array.

30. The method according to claim 22, wherein The detecting, with a plurality of detectors in a predetermined time sequence, the beam generated by the selected group of the plurality of lasers is repeated a plurality of times.

31. The method according to claim 22, wherein, The exciting, in a predetermined time sequence, the selected group of the plurality of lasers is repeated a plurality of times.

32. The method according to claim 22, wherein Said exciting a selected group of the plurality of lasers in a predetermined time sequence includes exciting the selected group of the plurality of lasers to emit light in a predetermined pattern.

33. The method according to claim 22, wherein Said exciting a selected group of the plurality of lasers in a predetermined time sequence includes exciting the selected group of the plurality of lasers to maintain a predetermined heat dissipation.

34. The method according to claim 22, wherein, Said detecting, with a plurality of detectors, the light beams generated by a selected group of the plurality of lasers in a predetermined time sequence includes detecting a single light beam.

35. The method according to claim 22, wherein, Said detecting, with a plurality of detectors, the light beams generated by a selected group of the plurality of lasers in a predetermined time sequence includes detecting in a region that provides a desired angular resolution for a specific measurement.

36. A solid-state optical detection and ranging LIDAR system, comprising: a) A plurality of lasers, each of the plurality of lasers generating a light beam with a field of view (FOV) when excited; b) A plurality of detectors located in the optical paths of the light beams generated by the plurality of lasers, each of the plurality of detectors having a detector signal output, wherein the FOV of at least one of the plurality of light beams generated by the plurality of lasers is greater than the FOV of at least one of the plurality of detectors and overlaps with the FOVs of at least two of the plurality of detectors; And c) A controller having a plurality of laser control outputs and a plurality of detector inputs, each of the plurality of laser control outputs being electrically connected to a bias input of one of the plurality of lasers, and each of the plurality of detector inputs being electrically connected to a detector signal output of one of the plurality of detectors. The controller is configured to generate a bias signal at the plurality of laser control outputs, the bias signal exciting a selected group of the plurality of lasers in a predetermined time sequence, the predetermined time sequence being selected to maintain a predetermined thermal condition, and the controller is configured to detect a predetermined sequence of detector signals generated by the plurality of detectors, the predetermined sequence of detector signals being selected to provide a desired measurement resolution.

37. The solid-state LIDAR system according to claim 36, wherein, At least some of the plurality of lasers include vertical cavity surface emitting lasers.

38. The solid-state LIDAR system according to claim 36, wherein, At least some of the plurality of lasers emit lasers of different wavelengths.

39. The solid-state LIDAR system according to claim 36, wherein, The plurality of lasers includes a two-dimensional laser array.

40. The solid-state LIDAR system according to claim 39, wherein, When excited by the controller, one row of the two-dimensional laser array emits a laser of one wavelength, and another row of the two-dimensional laser array emits a laser of a different wavelength when excited by the controller.

41. The solid-state LIDAR system according to claim 39, wherein, The selected group of the plurality of lasers includes a row of the two-dimensional array.

42. The solid-state LIDAR system according to claim 39, wherein, The selected group of the plurality of lasers includes a column of the two-dimensional array.

43. The solid-state LIDAR system according to claim 36, wherein, The plurality of detectors includes a two-dimensional detector array.

44. The solid-state LIDAR system according to claim 43, wherein, The controller is configured to sequentially sample detector signals from a row of the two-dimensional detector array.

45. The solid-state LIDAR system according to claim 43, wherein, The controller is configured to sequentially sample detector signals from a column of the two-dimensional detector array.

46. The solid-state LIDAR system according to claim 36, wherein, The controller is further configured to repeat the generation of the bias signal at the plurality of laser control outputs, the bias signal exciting a selected group of the plurality of lasers multiple times in the predetermined time sequence.

47. The solid-state LIDAR system according to claim 36, wherein, The controller is configured to detect a predetermined sequence of detector signals generated by the plurality of detectors in a sequence repeated multiple times.

48. The solid-state LIDAR system according to claim 36, wherein, The controller is configured to generate a bias signal at the plurality of laser control outputs, the bias signal exciting a selected group of the plurality of lasers at different wavelengths in the predetermined time sequence.

49. The solid-state LIDAR system according to claim 36, wherein, The controller is configured to generate a bias signal at the plurality of laser control outputs, the bias signal exciting a selected group of the plurality of lasers to emit light in a predetermined pattern.

50. The solid-state LIDAR system according to claim 49, wherein, The controller is configured to detect a predetermined sequence of detector signals generated by the plurality of detectors corresponding to the specific predetermined pattern of the light emitted from the plurality of lasers.

51. The solid-state LIDAR system according to claim 36, wherein, The controller is configured to generate a bias signal at the plurality of laser control outputs, the bias signal exciting a selected group of the plurality of lasers to emit light in a predetermined pattern, the light maintaining a Class 1 eye-safe optical power level in the pattern.

52. The solid-state LIDAR system according to claim 36, wherein, The controller is configured to generate a bias signal at the plurality of laser control outputs, the bias signal exciting a selected group of the plurality of lasers to maintain eye-safe conditions.

53. The solid-state LIDAR system according to claim 36, wherein, The controller is configured to detect a predetermined sequence of detector signals generated by detectors located in a region illuminated by a single laser beam FOV.

54. The solid-state LIDAR system according to claim 53, wherein, The detectors located in the region illuminated by the single laser beam FOV include all detectors illuminated by the single laser beam FOV.

55. The solid-state LIDAR system according to claim 53, wherein, The detectors located in the region illuminated by the single laser beam FOV include a subset of the detectors illuminated by the single laser beam FOV.

56. The solid-state LIDAR system according to claim 55, wherein, The subset of the detectors includes detectors forming a shape providing a desired angular resolution for a specific measurement.

Images