Beam shaping of ultra-small vertical-cavity surface-emitting laser (VCSEL) arrays

Abstract

A laser array includes a plurality of laser diodes disposed on the surface of an intrinsic substrate and electrically connected to each other. Respective laser diodes on the surface of the intrinsic substrate have different orientations relative to each other. The respective laser diodes are configured to provide coherent light emission in different directions, and the laser array is configured to emit an incoherent output beam comprising the coherent light emission from the respective laser diodes. The output beam may include incoherent light having a non-uniform intensity distribution over the field of view of the laser array. Related devices and fabrication methods are also discussed.

Description

[0001] This application is a divisional application of the Chinese national application (application number: 201880036100.6, date of entry into the Chinese national phase: November 29, 2019) corresponding to the international application PCT / US2018 / 027298 entitled “Beam shaping of ultra-small vertical cavity surface emitting laser (VCSEL) arrays” filed on April 12, 2018.

[0002] Priority requirements

[0003] This application claims priority to U.S. Provisional Patent Application No. 62 / 484,701, filed April 12, 2017, entitled “LIGHT DETECTION AND RANGING (LIDAR) DEVICES AND METHODS OF FABRICATING THE SAME,” and U.S. Provisional Patent Application No. 62 / 613,985, filed January 5, 2018, entitled “ULTRA-SMALLVERTICAL CAVITY SURFACE EMITTING LASER (VCSEL) AND ARRAYS INCORPORATING THESAME,” the disclosure of which is incorporated herein by reference. Technical Field

[0004] This invention relates to semiconductor-based lasers, related devices, and operating methods. Background Technology

[0005] Many emerging technologies, such as the Internet of Things (IoT) and autonomous navigation, can involve detecting and measuring distances to objects in three-dimensional (3D) space. For example, autonomous vehicles may require 3D detection and recognition for basic operations and to meet safety requirements. Indoor navigation may also require 3D detection and recognition, for example, through industrial or household robots or toys.

[0006] In some cases, light-based 3D measurement can outperform radar (low angular accuracy, bulky) or ultrasound (very low accuracy). For example, a light-based 3D sensor system can include detectors (such as photodiodes or cameras) and light-emitting devices (such as light-emitting diodes (LEDs) or laser diodes) as light sources that typically emit light outside the visible wavelength range. Vertical-cavity surface-emitting lasers (VCSELs) are one type of light-emitting device that can be used in light-based sensors to measure distance and velocity in 3D space. VCSEL arrays can allow for power scaling and can provide very short pulses at high power densities. Summary of the Invention

[0007] Some embodiments described herein relate to laser diodes and arrays including laser diodes, such as VCSELs or other surface-emitting laser diodes or edge-emitting laser diodes or other semiconductor lasers.

[0008] In some embodiments, the laser diode may be a surface-emitting laser diode. The laser diode includes a semiconductor structure comprising an n-type layer, an active region (which may include at least one quantum well layer), and a p-type layer. One of the n-type and p-type layers includes a laser aperture thereon, which defines an optical axis oriented perpendicular to the surface of the active region between the n-type and p-type layers. The laser diode also includes a first contact and a second contact electrically connected to the n-type and p-type layers, respectively. The first contact and / or the second contact is smaller than the laser aperture in at least one dimension.

[0009] In some embodiments, the laser diode may be an edge-emitting laser diode. The laser diode includes an n-type layer, an active region, a p-type layer, and a first contact and a second contact electrically connected to the n-type layer and the p-type layer, respectively. A laser aperture defines an optical axis oriented parallel to the surface of the active region between the n-type and p-type layers. The laser diode also includes the first contact and the second contact electrically connected to the n-type layer and the p-type layer, respectively. The first contact and / or the second contact may be smaller than the laser aperture in at least one dimension.

[0010] In some embodiments, a method is provided for manufacturing a laser diode such as a VCSEL or other surface-emitting laser diode or edge-emitting laser diode. The method may include: fabricating an array of discrete laser diodes using, for example, micro-transfer, electrostatic bonding, or other mass transfer techniques.

[0011] In some embodiments, an array of discrete laser diodes (also referred to herein as a laser diode array or laser array) is provided. The laser diode array may include surface-emitting laser diodes and / or edge-emitting laser diodes electrically connected in parallel and / or in series via thin-film interconnects on an intrinsically rigid and / or flexible substrate. The laser diode array may also include one or more driving transistors and / or other types / materials of devices (e.g., power capacitors, etc.) integrated within the array.

[0012] According to some embodiments, a laser array includes a plurality of laser diodes disposed on the surface of an intrinsic substrate and electrically connected to each other. Respective laser diodes among the plurality of laser diodes have different orientations relative to each other. The respective laser diodes are configured to provide coherent light emission in different directions, and the laser array is configured to emit an output beam comprising the coherent light emission from the respective laser diodes.

[0013] In some embodiments, the output beam may include incoherent light having a non-uniform intensity distribution over the field of view of the laser array. For example, the field of view may be about 80 degrees to about 180 degrees in some embodiments, or greater than about 150 degrees in others. In some embodiments, the laser array may be a LiDAR array.

[0014] In some embodiments, the non-intrinsic substrate may have curvature that provides different orientations for the respective laser diodes.

[0015] In some embodiments, the intrinsic substrate may include a flexible substrate bent to define curvature.

[0016] In some embodiments, the non-uniform intensity distribution is controllable in response to a control signal for changing the curvature of the flexible substrate and / or in response to the power supplied to the respective laser diode, for example, by selective addressing of the respective laser diode.

[0017] In some embodiments, the flexible substrate may be supported by at least one central axis element configured to move in one or more directions in response to the control signal, wherein the movement of the at least one central axis element changes the curvature of the flexible substrate.

[0018] In some embodiments, the surface may be the back side of the extrinsic substrate, wherein a corresponding laser diode may be arranged to provide coherent light emission through the extrinsic substrate, and the extrinsic substrate may be formed of a material that is transparent to the coherent light emission and configured to at least partially collimate the coherent light emission.

[0019] In some embodiments, corresponding features on the surface of the non-intrinsic substrate provide different orientations for at least one of the corresponding laser diodes. In some embodiments, the corresponding features may include uneven height features and / or recesses, the dimensions and spacing of which are configured to provide different orientations for the corresponding laser diodes. In some embodiments, the corresponding features may include corresponding patterned surfaces of the non-intrinsic substrate.

[0020] In some embodiments, the laser array can be configured to emit the output beam without refractive optical elements on the plurality of laser diodes.

[0021] In some embodiments, the lens array may be attached to an intrinsic substrate. The lens array may be configured to increase the divergence of the output beam in at least one dimension.

[0022] In some embodiments, the surface of the non-intrinsic substrate opposite the laser diode may define a lens array.

[0023] In some embodiments, the lens array may be formed of a flexible material having curvature corresponding to an intrinsic substrate and / or to different orientations of the respective laser diodes.

[0024] In some embodiments, the lens array may include: a primary lens array configured to increase the divergence of the output beam in a first direction; and an auxiliary lens array arranged to receive the output beam from the primary lens array and increase the divergence of the output beam in a second direction. For example, the first direction may correspond to the azimuth angle of the output beam, and the second direction may correspond to the elevation angle of the output beam.

[0025] In some embodiments, the lens array may include at least one of the following: a Fresnel lens, a plurality of shaping microlenses, or a plurality of spherical lenses.

[0026] In some embodiments, a respective spherical lens of the plurality of spherical lenses may be suspended above a respective subset of the plurality of laser diodes. The optical axis of the respective spherical lens may be offset relative to the optical axis defined by a respective laser aperture of a respective subset of the plurality of laser diodes.

[0027] In some embodiments, a subset of the plurality of laser diodes may define a column of the laser array, and the lens array may include cylindrical lenses aligned with the column.

[0028] In some embodiments, the corresponding laser diode may include residual wiring portions and / or gap features on its periphery.

[0029] In some embodiments, the spacing between adjacent laser diodes in a plurality of laser diodes may be less than about 500 micrometers, less than about 200 micrometers, less than about 150 micrometers, less than about 100 micrometers, or less than about 50 micrometers, but greater than about 30 micrometers, greater than about 20 micrometers, or greater than about 10 micrometers.

[0030] In some embodiments, a subset of the plurality of laser diodes may be electrically connected in series (or, anode to cathode, such that the anode of at least one laser diode of the subset of the plurality of laser diodes is connected to the cathode of an adjacent laser diode of the subset, or vice versa) on an intrinsic substrate.

[0031] In some embodiments, the corresponding laser diode may be a surface-emitting laser, and the corresponding laser aperture of the surface-emitting laser may define optical axes oriented in different directions. The corresponding electrical contact with the surface-emitting laser may be smaller than its corresponding laser aperture in at least one dimension orthogonal to the optical axis.

[0032] According to some embodiments, a method of manufacturing a laser array includes setting a plurality of laser diodes disposed on the surface of an intrinsic substrate and electrically connected to each other. Respective laser diodes among the plurality of laser diodes have different orientations relative to each other. The respective laser diodes are configured to provide coherent light emission in different directions, and the laser array is configured to emit an output beam comprising the coherent light emission from the respective laser diodes. In some embodiments, a micro-transfer process can be used to set the respective laser diodes on the surface of the intrinsic substrate.

[0033] Other devices, apparatuses, and / or methods according to some embodiments will become apparent to those skilled in the art after reviewing the following figures and detailed descriptions. In addition to any and all combinations of the embodiments described above, all such additional embodiments are contemplated and included within the scope of this invention and protected by the appended claims. Attached Figure Description

[0034] Figure 1 This is a diagram illustrating an exemplary light-based 3D sensor system according to some embodiments described herein.

[0035] Figure 2A This is a plan view of an example laser diode with reduced anode and cathode contact sizes according to some embodiments described herein.

[0036] Figure 2B yes Figure 2A A cross-sectional view of a laser diode.

[0037] Figure 2C This is a perspective view showing an example laser diode according to some embodiments described herein, compared to a conventional VCSEL chip.

[0038] Figure 3A This is a perspective view showing a distributed emitter array including laser diodes according to some embodiments described herein.

[0039] Figure 3B This is a perspective view showing a distributed emitter array including laser diodes on a curved substrate according to some embodiments described herein.

[0040] Figures 4A to 4F This is a perspective view illustrating an example manufacturing process of a laser diode according to some embodiments described herein.

[0041] Figures 4A' to 4G' This is a cross-sectional view illustrating an example manufacturing process for a laser diode according to some embodiments described herein.

[0042] Figures 5A to 5C These are images of VCSEL arrays assembled according to some embodiments described herein.

[0043] Figures 5D to 5E This is an enlarged image showing the residual tie portion and gap features of a VCSEL according to some embodiments described herein.

[0044] Figure 6A This is a perspective view illustrating an example emitter array comprising heterogeneous integration of distributed laser diodes and distributed drive transistors according to some embodiments described herein.

[0045] Figure 6B It shows Figure 6A A schematic diagram of the equivalent circuit of a distributed transmitter array.

[0046] Figure 6C It is along Figure 6A A cross-sectional view of the distributed transmitter array taken from line 6C-6C'.

[0047] Figure 6D It shows Figure 6A A schematic diagram of an alternative equivalent circuit for a distributed transmitter array.

[0048] Figure 7A This is a perspective view showing an example LIDAR device according to some embodiments described herein.

[0049] Figure 7B It shows Figure 7A An exploded view of example components of a LiDAR device.

[0050] Figure 7C This is a perspective view showing another example LIDAR device according to some embodiments described herein.

[0051] Figure 8 This is a block diagram illustrating an example system architecture of a LIDAR device according to some embodiments described herein.

[0052] Figure 9 This is a cross-sectional view showing an example laser diode array according to other embodiments described herein.

[0053] Figure 10A This is a perspective view showing a distributed emitter array including laser diodes on a curved substrate according to some embodiments described herein.

[0054] Figure 10BThis is a graph illustrating an example angular power distribution output from a distributed emitter array according to some embodiments described herein, wherein the distributed emitter array includes laser diodes on a curved substrate.

[0055] Figure 10C This illustrates the provision of some embodiments according to those described herein. Figure 10B Angular power distribution output Figure 10A A graphical representation of the example curvature of the substrate of a distributed emitter array.

[0056] Figure 10D This is a graph illustrating an example angular power distribution output from a distributed emitter array according to other embodiments described herein, wherein the distributed emitter array includes laser diodes on a curved substrate.

[0057] Figure 11A , Figure 11B and Figure 11C This is a cross-sectional view of an example distributed transmitter array including a shaping microlens array according to some embodiments described herein, the shaping microlens array being configured for high aspect ratio beam shaping.

[0058] Figure 12A and Figure 12B This is a cross-sectional view of an example distributed transmitter array including a self-aligned spherical lens array according to some embodiments described herein, wherein the self-aligned spherical lens array is configured for wide field-of-view beam shaping.

[0059] Figure 13A and Figure 13B This is a cross-sectional view of an example distributed transmitter array including an offset spherical lens array for beam shaping, according to some embodiments described herein. Figure 13C This is a perspective view showing this example distributed transmitter array.

[0060] Figure 14A , Figure 14B and Figure 14C This is a cross-sectional view of an example distributed emitter array including a lens array according to some embodiments described herein, wherein the lens array has a primary lens element and an auxiliary lens element configured for multi-directional beam shaping.

[0061] Figure 14D and Figure 14E This is a graph illustrating the effect of an optical diffuser film on beam shaping of a distributed emitter array according to some embodiments described herein.

[0062] Figure 15A , Figure 15B , Figure 15C , Figure 15E and Figure 15F This is a cross-sectional view of an example distributed emitter array including tilted laser diodes for lensless beam shaping, according to some embodiments described herein. Figure 15D This is a plan view showing this example distributed transmitter array. Detailed Implementation

[0063] The embodiments described herein may stem from the understanding that, in emerging technologies, more compact optical emitter arrays may be advantageous. For example, such as Figure 1 As shown, using a pulsed light-emitting device array 120 as a light source, a light-based 3D sensor system 100 (e.g., a light detection and ranging (LIDAR) system) can use a time-of-flight (TOF) based measurement circuit 110 and a 3D image reconstruction circuit 150 based on signals received from an optical detector circuit 130 and associated optics 140. The time-of-flight measurement circuit 110 determines the distance d to the target T (where d = ((speed of light (c) / 2) x ToF)) by measuring the round-trip time (“Time of Flight”; ToF) of the laser pulse 109 reflected by the target T. The 3D image reconstruction circuit 150 can use the distance d to create an accurate 3D map of the surrounding environment. Some advantages of the LIDAR system can include long range; high accuracy; excellent object detection and recognition; high resolution; high sampling density 3D point clouds; and effectiveness under various lighting and / or weather conditions. Applications of the LIDAR system can include ADAS (Advanced Driver Assistance Systems), autonomous vehicles, UAVs (Unmanned Aerial Vehicles), industrial automation, robotics, biometrics, modeling, augmented and virtual reality, 3D mapping, and security. Figure 1 The example illustrates a flash LIDAR system in which the pulsed light-emitting device array 120 emits light over a relatively large area for a short time to acquire an image, compared to some conventional scanning LIDAR techniques (which generate image frames via raster scanning). However, it should be understood that the light-emitting device array 120 described herein can also be used in scanning LIDAR implementations.

[0064] Still referencing Figure 1 The light-emitting device array 120 may include multiple electrically connected surface-emitting laser diodes, such as VCSELs, and can be operated using strong single pulses with low duty cycles or using pulse trains (which typically have wavelengths outside the visible spectrum). Due to its sensitivity to background light and the signal attenuation with distance, a target T at a distance d, where the distance d is up to about 100 meters or longer, can be detected using laser power of a few watts.

[0065] However, some conventional VCSELs can have sizes defined from approximately 150 micrometers (μm) to approximately 200 μm (e.g., length, width, and / or diameter), which can impose size and / or density limitations on sensor systems that include discrete VCSEL arrays. This relatively large VCSEL size may require compatibility with conventional pick-and-place machines and necessitates sufficient contact surface area for wire bonding pads to provide electrical connection to the VCSEL. For example, some conventional solder ball or wire bonding techniques may require lengths exceeding approximately 30 μm just for bonding pads, while the tips used to pull the wire bond may have precision on the order of tens of micrometers.

[0066] Some embodiments described herein provide light-emitting devices such as surface-emitting laser diodes (e.g., VCSELs) with reduced dimensions (e.g., length and / or width of about 30 micrometers (μm) or less) without compromising device performance (e.g., power output). For example, the diameter of the aperture (the active region where lasing occurs) of a VCSEL die can be from about 10 μm to about 20 μm. By reducing or eliminating wasted (non-active) areas and by reserving a combined chip length of a few micrometers (e.g., from about 4 μm to about 6 μm or less) for the anode and cathode contacts, the die length can be reduced to the aperture diameter plus a few micrometers. This can reduce the dimensions (e.g., length and / or width) by about 10 times or more (e.g., a die length of about 15 μm to about 20 μm compared to some conventional VCELs with die lengths of about 150 μm to about 200 μm). In some embodiments, these reduced die sizes can allow the fabrication of emitter arrays comprising a higher density (e.g., thousands) of VCSELs or other laser diodes.

[0067] Figure 2A and Figure 2B This illustrates plan and cross-sectional views of an example surface-emitting light-emitting device (shown as a vertical-cavity surface-emitting laser diode (VCSEL) chip or die 200, also referred to herein as VCSEL 200) according to some embodiments described herein, the VCSEL 200 including an anode contact 211 and a cathode contact 212 smaller than a laser aperture 210 in at least one dimension. Figure 2A and Figure 2B As shown, the VCSEL 200 includes an active region 205 with one or more quantum wells 203 to generate and emit coherent light 209. The optical cavity axis 208 of the VCSEL 200 is oriented along the current direction (rather than perpendicular to the current as in some conventional laser diodes), thereby defining a vertical cavity with a length along the current direction. The cavity length of the active region 205 can be short compared to the lateral dimension of the active region 205, such that the radiation 209 exits from the surface of the cavity rather than from its edges.

[0068] Active region 205 may be sandwiched between distributed Bragg reflector (DBR) mirror layers (also referred to herein as Bragg reflector layers or Bragg mirrors) 201 and 202, which are disposed on lateral conduction layer (LCL) 206. In some embodiments, LCL 206 may allow for improved electrical and / or optical properties (compared to direct contact reflector layer 401). In some embodiments, a printed interface 215 may be provided on the surface of LCL layer 206, including an adhesive layer that improves adhesion to the underlying layer or substrate. The adhesive layer may be optically transparent for one or more wavelength ranges and / or may be refractively matched to provide the desired optical performance. Reflector layers 201 and 202 at the cavity ends may be made of alternating high-refractive-index layers and low-refractive-index layers. For example, reflector layers 201 and 202 may include alternating layers of thickness d1 and d2 with refractive indices n1 and n2, such that n1d1 + n2d2 = λ / 2, to provide wavelength-selective reflectivity at the emission wavelength λ. This vertical configuration increases compatibility with semiconductor manufacturing equipment. For example, since the VCSEL emits light 209 perpendicular to the active region 205, thousands of VCSELs can be processed simultaneously, for example, by using standard semiconductor wafer processing steps to define the emission area and electrical terminals of the corresponding VCSEL on a single wafer.

[0069] Although this document primarily refers to VCSEL structures, it should be understood that the embodiments described herein are not limited to VCSELs, and laser diode 200 may include other types of laser diodes configured to emit light 209 along optical axis 208, wherein optical axis 208 is oriented perpendicular to the substrate or other surface on which device 200 is disposed. It should also be understood that although this document primarily refers to surface-emitting laser structures, the laser diodes and laser diode arrays described herein are not limited to these and may include, for example... Figure 9 The diagram includes an edge-emitting laser structure configured to emit light along an optical axis oriented parallel to the substrate or other surfaces on which the same device is disposed.

[0070] VCSEL 200 can be formed of a material selected to provide light emission within a desired wavelength range, which may be outside the visible spectrum. For example, in some embodiments, VCSEL 200 may be a gallium arsenide (GaAs) based structure. In a specific embodiment, active region 205 may include one or more GaAs-based layers (e.g., alternating InGaAs / GaAs quantum wells and blocking layers), and Bragg mirrors 201 and 202 may include GaAs and aluminum gallium arsenide (AlGaAs)... x Ga(1-x) (As). For example, the lower Bragg mirror 201 may be an n-type structure comprising alternating layers of n-AlAs / GaAs, while the upper Bragg mirror 202 may be a p-type structure comprising alternating layers of p-AlGaAs / GaAs. Although the reference to GaAs-based VCSELs has been described by way of example, it should be understood that the materials and / or material composition of layers 201, 202, and / or 205 may be adjusted and / or otherwise selected to provide light emission at a desired wavelength, for example, by using emission materials with shorter wavelengths (e.g., GaN-based) and / or longer wavelengths (e.g., InP-based).

[0071] exist Figure 2A and Figure 2B In the example, the VCSEL 200 includes a laser aperture 210 with a size of approximately 12 μm (shown as diameter D), and a first conductive contact terminal and a second conductive contact terminal (shown as anode contact 211 and cathode contact 212, also referred to herein as the first contact and the second contact). A first conductive film interconnect 213 is disposed on the first contact 211, and a second conductive film interconnect 213 is disposed on the second contact 212 to provide electrical connection with the VCSEL 200. Figure 2B A cross-section of the anode contact 211 and cathode contact 212 having conductive film interconnects 213 thereon is shown more clearly. The first contact 211 and the second contact 212 can provide contact to semiconductor regions of opposite conductivity types (P-type and N-type, respectively). Therefore, the embodiments described herein are configured to transfer electrical energy to VCSEL contacts 211 and 212 via thin-film interconnects 213 instead of using wire bonding, strips, cables, or leads, wherein the thin-film interconnects 213 can be formed by patterning conductive films. The interconnects 213 can be formed after the VCSEL 200 is disposed on a target substrate (e.g., an intrinsic substrate different from the source substrate on which the VCSEL 200 is formed), for example using conventional photolithography techniques, and can be configured to have low resistance. Thus, the material used for the conductive film interconnects 213 can include aluminum or aluminum alloys, gold, copper, or other metals formed to a thickness of about 200 nm to about 500 nm.

[0072] like Figure 2A As shown, the first conductive contact 211 and the second conductive contact 212 are smaller than the aperture 210 in one or more dimensions. In some embodiments, allowing the size of each of the contacts 211, 212 to be from about 2 μm to about 3 μm can significantly reduce the overall size of the VCSEL die 200. For example, for the anode and cathode contacts, each with a length of 2 μm, the dimension L can be reduced to about 16 μm (2 μm anode length + 12 μm aperture + 2 μm cathode length; all measured along dimension L), thereby providing a 16x16 μm. 2The die. As another example, for the anode and cathode contacts, each with a length of 3 μm, the dimension L can be reduced to approximately 18 μm (3 μm anode + 12 μm aperture + 3 μm cathode), thus providing an 18x18 μm die. 2 The die size L can also be reduced or slightly increased for smaller or larger orifice sizes D (e.g., 10 μm) or larger orifice sizes D (e.g., 20 μm). More generally, the VCSEL die 200 according to the embodiments herein can achieve a contact area to orifice area ratio of about 0.05 to 30, about 0.1 to 20, about 1 to 10, or about 1 to 3, wherein the contact area refers to the surface area of ​​the electrical contacts 211 and / or 212 located on or adjacent to the orifice 210 on the surface S. Moreover, although the contacts 211, 212 and interconnects 213 are shown in specific locations relative to the orifice 210, it should be understood that the embodiments described herein are not limited thereto, and the contacts 211, 212 and interconnects 213 can be disposed in other areas of the VCSEL die 200 (e.g., at corners, etc.).

[0073] The VCSEL 200 according to some embodiments described herein can be configured to emit light at a power greater than about 100 milliwatts (mW) over a wide pulse width of about 1–10 nanoseconds (ns), which may be useful for LIDAR applications. In some embodiments, for example due to reduced capacitance (and a corresponding reduction in the RLC time constant) compared to some conventional VCSELs, a peak power output greater than 1 watt with a 1 ns pulse width at a 10000:1 duty cycle can be obtained from a single VCSEL element 200. Combined with a range greater than about 200 meters (m) (based on the extremely high power emitter and increased detector sensitivity), the VCSEL 200 described herein can therefore allow for a long laser lifetime (based on low laser operating temperature at high pulse power).

[0074] Figure 2C This is a plan view of a VCSEL chip 200 according to some embodiments described herein, compared to a conventional VCSEL chip 10. (See attached diagram.) Figure 2C As shown, a conventional VCSEL chip 10 can have a length L of approximately 200 μm, providing sufficient area for the active region 5 and the top wire bonding pad 11, which can be used as an n-type or p-type contact. In contrast, the VCSEL chip 200 described herein according to some embodiments can have a length L of approximately 20 μm or less. Because electrical connections to smaller contacts 211, 212 are established via thin-film metallization interconnects 213, the VCSEL chip 200 described herein according to some embodiments does not require bonding pads, allowing the optical aperture 210 to occupy a large portion of the entire surface area of ​​the light-emitting surface S.

[0075] Therefore, the size of the VCSEL chip 200 according to some embodiments of the present invention can be 1 / 100th the size of some conventional VCSEL chip 10, thereby allowing for an increase of up to one hundred times in power per unit area of ​​the emitter surface S and a reduction in capacitance, which can significantly reduce the RLC time constant associated with the driving fast pulses in these devices. This exponential reduction in size allows the fabrication of VCSEL arrays comprising thousands of closely spaced VCSELs 200, some of which are electrically connected in series (or, anode to cathode) on a rigid or flexible substrate, which is impossible for some conventional closely spaced VCSELs fabricated on a shared electrical substrate. For example, as described in more detail below, multiple dies 200 according to some embodiments described herein can be assembled and electrically connected within the footprint of a conventional VCSEL chip 10. In some applications, this reduction in size and elimination of bonding pads can allow for reductions in cost, device capacitance, and / or device thermal output (up to one hundred times) compared to some conventional VCSEL arrays.

[0076] Figure 3A This is a perspective view illustrating a distributed emitter array 300a including a laser diode (shown as VCSEL 200) according to some embodiments described herein. The array 300a (also referred to herein as a distributed VCSEL array (DVA)) can be assembled on an intrinsic substrate 307a, for example, by micro-transfer, electrostatic bonding, or other mass transfer techniques. As used herein, an intrinsic substrate (also referred to herein as a target substrate) can refer to the substrate on which the laser diode 200 is disposed or placed, which is different from the intrinsic substrate (also referred to herein as a source substrate) on which the laser diode 200 is grown or otherwise formed. The substrate 307a may be rigid in some embodiments, or flexible in others, and / or may be selected to provide improved thermal properties compared to the source substrate. For example, in some embodiments, the intrinsic substrate 307a may be thermally conductive and may also be electrically insulating (or coated with an insulating material such as oxides, nitrides, polymers, etc.). The conductive thin-film interconnect 313 can be formed to electrically connect corresponding contacts of the laser diodes 200 in a series and / or parallel configuration, and can be similar to the interconnect 213 described above. This allows for dynamically adjustable configuration by controlling the operation of a subset of the laser diodes 200 electrically connected by the conductive thin-film interconnect 313. In some embodiments, the array 300a may include wiring 313 between VCSELs 200 that are not connected in parallel (e.g., without a shared or common cathode / anode connection). That is, the conductive thin-film interconnect 313 can provide many variations of series / parallel interconnects, as well as additional circuit elements (e.g., bypasses, fuses, etc.) that impart better yield.

[0077] Conductive thin-film interconnects 313 can be formed during, before, and / or after the parallel process of setting the laser diodes 200 on the substrate 307a. For example, the conductive thin-film interconnects 313 can be formed by patterning conductive films on the substrate 307a using conventional photolithography techniques, such that the laser diodes 200 of the array 300 have no electrical connections that cross the substrate 307a.

[0078] Due to the small size of the laser diodes 200 and the connections provided via conductive thin-film interconnects 313, the spacing or pitch between two adjacent laser diodes 200 is less than about 500 micrometers (μm), or in some embodiments, less than about 200 μm, or less than about 150 μm, or less than about 100 μm, or less than about 50 μm, without a connection to a shared or common cathode / anode. While some monolithic arrays can have laser diode spacing less than about 100 μm, to achieve such close spacing, the laser diodes in such an array can electrically share a cathode / anode and can mechanically share a rigid substrate. In contrast, in some embodiments, laser diode arrays as described herein (e.g., array 300a) can achieve a spacing of less than about 150 μm between an intrinsic substrate (e.g., a rigid or flexible substrate) and adjacent, series-connected laser diodes 200 (without a common anode or cathode connection). Additionally, see the following references... Figures 6A to 6C As described in the examples, some embodiments of this disclosure can be integrated between other types of devices and / or devices formed of different materials (e.g., power capacitors, FETs, etc.) between laser diodes 200 having a spacing of less than 500 μm as described herein.

[0079] Furthermore, in some embodiments, the concentration of laser diodes 200 in each region of array 300a can be different in different parts of array 300a. For example, some LIDAR sensor applications may benefit from higher resolution in the central portion of the array (corresponding to the forward direction of travel), but may not require high resolution in the peripheral regions of the array. Thus, in some embodiments, the concentration of VCSELs 200 in the peripheral portion of array 300a can be less than the concentration of VCSELs 200 in the central portion of array 300a. Figure 3B As shown, this configuration can be used in applications where the substrate is flexible and can be bent or folded into a desired shape.

[0080] Figure 3BThis is a perspective view of a distributed emitter array 300b comprising laser diodes 200 on a curved, intrinsic substrate 307b according to some embodiments described herein. In some embodiments, the substrate 307b is formed of a flexible material that can be bent to provide curved emitting surfaces, such that VCSELs 200 mounted on a central portion 317 of the substrate 307b face forward, while VCSELs 200 mounted on a peripheral portion 317′ of the substrate 307b face an inclined direction. Since the VCSELs 200 emit light in a direction perpendicular to their active regions, the VCSELs 200 mounted on the central portion 317 of the substrate 307b emit light 309 in the forward direction, while the VCSELs 200 mounted on the peripheral portion 317′ of the substrate 307b emit light 309′ in the inclined direction, thereby providing a wide field of view. In some embodiments, each VCSEL can provide narrow field illumination (e.g., coverage of less than about 1 degree), and arrays 300a, 300b can include hundreds or thousands of VCSELs 200 (e.g., an array of 1500 VCSELs, each covering a field of view of about 0.1 degrees, thereby providing a field of view of 150 degrees).

[0081] By changing the curvature of substrate 307b, the field of view can be adjusted or changed as desired within a range from 0 degrees to approximately 180 degrees. The curvature of substrate 307b may or may not be a constant radius, and therefore can be designed or otherwise selected to provide a desired power distribution. For example, substrate 307b may define a cylindrical, non-cylindrical, spherical, or non-spherical curve that provides a desired distribution of relative power amounts to the normal surface. In some embodiments, the curvature of substrate 307b can be dynamically changed by mechanical or electromechanical actuation. For example, a mandrel can be used to form a flexible, intrinsic substrate 307b with a cylindrical or non-cylindrical shape. In some embodiments, the mandrel can also serve as a heat sink. Furthermore, as described above, in some embodiments, the spatial density or concentration of VCSEL 200 in the peripheral portion of array 300b may be less than the spatial density or concentration of VCSEL 200 in the central portion of array 300b. For example, rows or columns of an array 300b of VCSEL 200 can be arranged on an intrinsic substrate 307b with different and / or non-uniform spacing using techniques such as micro-transfer and / or other micro-assembly techniques to provide a desired far-field output light pattern.

[0082] Figure 3A and Figure 3BThe arrays 300a and 300b shown can be scaled based on the desired number or resolution of the laser diodes 200, allowing for long-distance and high pulse power output (kilowatt (kW) level). The spatial density or distribution of the laser diodes 200 on the surfaces of substrates 307a and 307b can be selected to reduce the optical power density, thereby providing long-distance and eye-safety at the desired operating wavelength (e.g., approximately 905 nm for GaAs VCSELs; approximately 1500 nm for InP VCSELs). The desired optical power density can be further achieved by controlling the duty cycle of the signal applied to the VCSEL and / or by changing the curvature of the substrate. Moreover, the spacing or interval between adjacent laser diodes 200 within arrays 300a and 300b can be selected based on the substrate material to provide thermal management and improve heat dissipation during operation. For example, a spacing greater than approximately 100 micrometers (μm) between two adjacent laser diodes 200 can provide thermal advantages, particularly for substrates with limited thermal conductivity. Therefore, the arrays 300a and 300b described herein can provide higher reliability by eliminating wire bonding, providing a fault-tolerant architecture, and / or providing a lower operating temperature. In other embodiments, self-aligned, low-cost beam-shaping micro-optics (e.g., spherical lens arrays) can be integrated on or within the surfaces of arrays 300a and 300b.

[0083] In some embodiments, Figure 3A and Figure 3BThe compact arrays 300a and 300b shown can be fabricated using microtransfer (MTP), electrostatic bonding, and / or other massively parallel chip processing techniques, which allow for the simultaneous assembly and heterogeneous integration of thousands of microdevices on an intrinsic substrate via epitaxial lift-off. For example, arrays of VCSEL 200 can be fabricated using a microtransfer process similar to that described, for example, in U.S. Patent No. 7,972,875, entitled "Optical Systems Fabricated By Printing-Based Assembly," by Rogers et al., the disclosure of which is incorporated herein by reference in its entirety. Alternatively, arrays of VCSEL 200 can be fabricated using electrostatic bonding or gripping transfer techniques similar to those described, for example, in U.S. Patent No. 8,789,573, entitled "Micro device transfer headheater assembly and method of transferring a micro device," by Bibl et al., the disclosure of which is incorporated herein by reference in its entirety. In some embodiments, MTP, electrostatic bonding, and / or other mass transfer techniques can allow for the fabrication of arrays of VCSELs or other laser diodes with smaller inter-device spacing as described herein.

[0084] Figures 4A to 4F as well as Figures 4A' to 4G' This is a perspective view and a cross-sectional view illustrating an example manufacturing process of a laser diode (shown as VCSEL 400) according to some embodiments described herein. In some embodiments, the VCSEL 200 described herein may also use... Figures 4A to 4F One or more processing operations are shown to manufacture it. For example... Figures 4A to 4F as well as Figures 4A' to 4G' As shown, the ultra-small VCSEL 400 described herein according to embodiments can be grown on a source substrate and assembled on an intrinsic target substrate using microtransfer technology. Specifically, in Figure 4A and Figure 4A'In this configuration, a sacrificial layer 408, a lateral conductive layer 406, a first n-type distributed Bragg reflector (DBR) layer 401, an active region 405, and a second p-type DBR layer 402 are sequentially formed on a source wafer or substrate 404. Although the fabrication is illustrated with reference to a single VCSEL 400, it should be understood that multiple VCSELs 400 can be fabricated simultaneously on the source wafer 404 by reducing or minimizing the spacing between adjacent VCSELs 400 to increase or maximize the number of VCSELs that can be fabricated simultaneously on the wafer 404. Furthermore, it should be understood that multiple VCSEL devices can be fabricated on a single die or chiplet released from the substrate 404 used for printing. Moreover, the transfer printing technique described in more detail below allows for the reuse of the source wafer 404 for subsequent fabrication of additional VCSELs.

[0085] In some embodiments, the material composition of layers 406, 401, 405, and 402 can be selected to provide a desired emission wavelength and emission direction (optical axis). For example, in some embodiments, layers 406, 401, 405, and 402 may be based on gallium arsenide (GaAs) or indium phosphide (InP). As shown, a lateral conductive layer 406, an AlGaAs n-type high-reflectivity distributed Bragg reflector (DBR), and an active region 405 are sequentially formed on a source wafer 404. The active region 405 may be formed to include an InAlGaAs strained quantum well designed to provide light emission at the desired wavelength, and subsequently a p-type DBR output mirror 402 is formed. A top contact metallization process is performed to form a p-contact (e.g., an anode contact) 411 on the p-type DBR layer 402. For example, Ti / Pt / Au annular contacts of different sizes may be deposited to form the anode or p-contact 411. A hole 410 may be defined around the periphery of the p-contact 411. In some embodiments, an oxide layer may be disposed between the active region 405 and the p-type DBR layer 402 to define the boundary of the aperture 410. The layout and design of the aperture 410 can be selected to minimize optical loss and current diffusion.

[0086] exist Figure 4B and Figure 4B' In the process, a top mesa etching process is performed to expose the top surface of the active region 405 and the n-type DBR layer 401, and an oxidation process is performed to oxidize the exposed surfaces (including the exposed sidewalls of the active region 405), particularly the lateral defining boundary of the optical aperture 410. Figure 4C and Figure 4C′ In this process, a bottom contact metallization process is performed to expose and form an n-type (e.g., cathode) contact 412 on the surface of the lateral conductive layer 406. It should be understood that in some embodiments, the n-type contact 412 may alternatively be formed on the n-type DBR layer 401 to provide a top-side contact. Figure 4D and Figure 4D'In this process, an isolation process is performed to define a corresponding lateral conduction layer 406, and an anchor material (e.g., a photoresist layer) is deposited and etched to define a photoresist anchor 499 and an entrance for exposing the sacrificial release layer 408 for epitaxial stripping.

[0087] exist Figure 4E and Figure 4E′ In this process, an undercut etching process is performed to remove a portion of the sacrificial release layer 408, causing the anchor 499 to suspend the VCSEL die 400 above the source wafer 404. In some embodiments, Figure 4E and Figure 4E′ After this operation, a micro-transfer printing process can be used, such as... Figure 4F and Figure 4F′ As shown, the micro-transfer process can utilize an elastomer and / or other molding compound 490 to break the anchor 499, bonding the VCSEL die 400 (along with multiple other VCSEL dies 400 on the source wafer 404) to the surface of the molding compound 490, and as... Figure 4G′ As shown, multiple VCSEL dies 400 (already bonded to the surface of the mold) are transferred to the surface of the non-intrinsic target substrate 407 by contacting the surface of the mold on which the die 400 is located. In other embodiments, Figure 4F The operation can be followed by an electrostatic clamp-based transfer process, which uses the attraction of opposite charges to bond the VCSEL die 400 (along with a plurality of other VCSEL dies 400 on the source wafer 404) to the surface of the electrostatic transfer head, while simultaneously transferring the VCSEL die 400 to the intrinsic target substrate. As a result of the disruption of the anchor 499, each VCSEL die 400 may include a broken or fractured tie portion 499t (e.g., a residual portion of the anchor structure 499) protruding from or recessed into the edge or side surface of the die 400 (and / or a corresponding gap feature at the periphery of the die 400), which may be retained when the VCSEL die 400 is transferred to the intrinsic substrate 407.

[0088] The intriguing target substrate can be a rigid or flexible destination substrate for a VCSEL array, or it can be a smaller sandwich or "chiplet" substrate. When the target substrate is a destination substrate for an array, the interconnect process can form a conductive thin film layer on the target substrate, on which assembled VCSEL dies 400 are located, and the conductive thin film layer can be patterned to define thin-film metal interconnects that provide the desired electrical connection between the VCSEL dies 400. The interconnect process can be performed after the VCSEL dies 400 are assembled on the destination substrate, or a pre-patterning process can be performed on the destination substrate before assembling the VCSEL dies 400, so that the electrical connection between the VCSEL dies is achieved during assembly (no interconnect processing is required after the dies 400 are transferred onto the substrate). When the target substrate is a chiplet, the VCSEL dies 400 can be connected in parallel via chiplets. The chiplets including the VCSEL die 400 can then be assembled (by transfer, electrostatic adsorption, or other transfer processes) onto a destination substrate for the array, wherein the destination substrate can be pre-patterned or post-patterned to establish electrical connections between the chiplets. In some embodiments, thin-film metal interconnects may be defined on and / or around broken tie portions protruding from the edge of the die 400.

[0089] Because VCSEL 400 is produced via epitaxial lift-off, it is separated from the substrate. Furthermore, due to the use of thin-film interconnects, VCSEL 400 can be thinner than some conventional VCSELs that remain attached to their intrinsic substrate, for example… Figure 2C VCSEL 10. For example, VCSEL 400 can have a thickness t of about 1 micrometer (μm) to about 20 μm (e.g., the combined thickness of a semiconductor stack including layers 406, 401, 405 and 402).

[0090] Figures 5A to 5C These are images of a VCSEL array 500 according to some embodiments described herein, assembled using a micro-transfer process. Specifically, Figure 5A A VCSEL array 500 with approximately 11,000 lasers is shown, assembled on an intrinsic substrate 507, with the VCSEL spacing between adjacent VCSELs 200 being approximately 200 micrometers (μm) or less. Figure 5B Inserted images and Figure 5CThe image shows an enlarged view of a portion of an array 500 comprising approximately 350 lasers and 9 lasers, respectively, according to some embodiments described herein. Due to the reduced size of the VCSELs described herein, in some embodiments, the inter-VCSEL spacing between adjacent VCSELs 200 may be less than approximately 150 μm, or less than approximately 100 μm, or less than approximately 50 μm on the source substrate. In some embodiments, the array 500 may be 5 square millimeters (mm²). 2 (or smaller) occupies 100 or more VCSELs within a space or area.

[0091] Figures 5D to 5E This is an enlarged image showing the fracture lines and gap characteristics of a VCSEL structure according to some embodiments described herein. Figure 5D and Figure 5E As shown, the transferred VCSEL 510 (e.g., one of the VCSEL 200s in a VCSEL 200) or other laser diodes as described herein may include one or more broken tie portions 499t and / or gap features 599 on its periphery. The gap features 599 may be patterned or otherwise positioned along the periphery of the VCSEL 510 to partially define the tie 499 and an area for preferential fracture of the tie 499. Figures 5D to 5E In the embodiments described herein, the broken tie portion 499 and the gap feature 599 are shown as existing along the periphery of the transverse conductive layer (LCL) 506; however, it should be understood that the broken tie portion 499 and / or the gap feature 599 may exist in or along the periphery of any layer disposed on an intrinsic substrate by the transfer process described herein, such as in... Figures 4A to 4F and Figures 4A' to 4G' In the example, epitaxial growth layers 406, 405, 401, and 402 are formed in the active region 405 on the source wafer or substrate 404. Thus, in some embodiments, the material and thickness of the broken tie portion 499t can correspond to the material and thickness of the LCL layer 506 (or other layers associated with the active region). In other embodiments, to shorten the etching process, the periphery or edge portion of the LCL 506 can be partially etched, so the gap pattern 599 of the tie feature 499t can be thinner than the LCL 506 (or other layers associated with the active region). During a "pick-up" operation (e.g., Figure 4G′As shown, the breakage of the tie 499 can occur within the resist layer 4991 itself, and the material and thickness of the broken tie portion 499t can correspond to the material and thickness of the resist layer 4991. The broken tie portion 499t can interact with the printing adhesive or epoxy resin and remains on the fully treated device even after resist development and / or resist removal processes. More generally, some laser diode structures according to embodiments described herein may include at least one of a broken tie portion 499t or a gap pattern or feature 599 located in the region near the tie 499 along the periphery or edge of the laser diode structure.

[0092] Therefore, some embodiments described herein can use MTP to print or integrate hundreds or thousands of VCSELs or other surface-emitting laser diodes into a space-saving light-emitting array. MTP can be advantageous by allowing simultaneous manipulation and wafer-level assembly of thousands of laser diode devices. In some embodiments, each laser diode can have an aperture size as small as about 1-10 μm, thereby reducing the size (and cost) of the laser incorporating such a VCSEL array by up to 100 times. To achieve different performance characteristics, such as modified near-field and far-field patterns, other embodiments may include substrates with aperture sizes even smaller than 1 μm. To achieve higher power output per VCSEL device, other embodiments may use larger apertures, such as about 10 to 100 μm. Moreover, MTP allows the reuse of source wafers (e.g., GaAs or InP) after the transfer process to grow new devices, further reducing manufacturing costs (in some cases, by up to 50%). MTP also allows for the direct heterogeneous integration and interconnection of laser diodes and / or driving transistors (as discussed below) from different material systems (e.g., GaAs or InP lasers) on a silicon integrated circuit (IC). Furthermore, source wafers can be used and reused cost-effectively to fabricate laser diodes (e.g., InP-based VCSELs) that provide high power and eye safety while reducing environmental noise. Thus, MTP can be used in some embodiments to reduce emitter costs and allows for the fabrication of high-power, high-resolution distributed VCSEL arrays (DVAs) comprising hundreds or thousands of VCSELs.

[0093] Furthermore, when disposed on a flexible or curved substrate, the embodiments described herein can provide a wide field of view (FoV) of up to 180 degrees. In some embodiments, the optical power distributed through the DVA can be configured for eye safety and efficient heat dissipation. In some embodiments, low-cost, self-aligned, beam-shaping micro-optics can be integrated within a curved DVA.

[0094] Figure 6AThis is a perspective view illustrating an example emitter array 600 comprising a heterogeneous integration of distributed surface-emitting laser diodes (shown as VCSEL 200) and distributed drive transistors 610 according to some embodiments described herein. As used herein, distributed circuit elements can refer to laser diodes, drive transistors, and / or other circuit elements assembled at various desired locations throughout the laser diode array, and such an array of distributed circuit elements is referred to herein as a distributed array. For example, integrating distributed high-power drive transistors in a distributed VCSEL array may be advantageous for LIDAR applications. Figure 6B It shows Figure 6A A schematic diagram of the equivalent circuit of the distributed transmitter array 600, and Figure 6C It is along Figure 6A A cross-sectional view of the distributed transmitter array 600 taken from line 6C-6C′.

[0095] like Figures 6A to 6C As shown, array 600 (also referred to herein as DVA) can be assembled on an intrinsic substrate 607, for example, by microtransfer or other techniques. Substrate 607 may be rigid in some embodiments or flexible in others. Array 600 also includes integrated driver transistors 610, which are assembled adjacent to one or more VCSELs 200 on substrate 607. In some embodiments, driver 610 and laser diode 200 may include different semiconductor materials and / or techniques with incompatible fabrication processes. For example, driver transistor 610 may be assembled on substrate 607 using a microtransfer (MTP) process. In some embodiments, an array comprising hundreds or thousands of driver transistors 610 may be provided. Conductive thin-film interconnects 613 may be formed to electrically connect the corresponding contacts of driver transistors 610 and laser diode 200 in a series and / or parallel configuration. The spacing between the driving transistor 610 and the adjacent laser diode 200 can be less than about 2 mm, less than about 1 mm, less than about 500 micrometers, less than about 150 micrometers (μm), or in some embodiments, less than about 100 μm or less than about 50 μm, which can provide reduced parasitic impedance between them (e.g., up to 100 times smaller than if the driving transistor 610 were located outside the chip or substrate).

[0096] In some embodiments, array 600 may include wiring 613 between VCSELs 200 that are not connected in parallel (e.g., without a common cathode / anode). Interconnect designs that do not simply connect all elements of the array in parallel (e.g., without a common anode or cathode connection) can offer the advantage of reducing the array's current requirements, which can reduce inductor losses and increase switching speed. Various interconnect designs also provide for other devices (e.g., switches, gates, FETs, capacitors, etc.) embedded or integrated within the electrically interconnected array, as well as fault-tolerant structures (e.g., fuses, bypass circuits, etc.) implemented in array fabrication, thus providing yield advantages. For example, as... Figure 6B As shown, array 600 includes a plurality of VCSEL strings 200 electrically connected in series (or, anode to cathode) to define columns (or other subsets or subarrays) of array 600. Array 600 also includes an array of driving transistors 610, wherein each driving transistor 610 is electrically connected in series to a corresponding string of VCSELs 200 that are connected in series (or anode to cathode).

[0097] The laser diode 200 and the driving transistor 610 can be patterned on the substrate 607 using, for example, conventional photolithography techniques, followed by the formation of conductive thin-film interconnects 613 in parallel processes. Thus, the driving transistor 610 and the laser diode 200 of the array 600 have no lead bonding and / or electrical connections through the substrate 607. Due to the small size of the laser diode 200 and the driving transistor 610 and the precision of the assembly techniques described herein, the spacing between adjacent laser diodes 200 and / or driving transistors 610 can be less than about 150 micrometers (μm), or in some embodiments, less than about 100 μm or less than about 50 μm. Therefore, integrating the drive transistor 610 close to the VCSEL 200 on the substrate 607 (e.g., at a distance of less than about 2 mm, less than about 1 mm, less than about 500 micrometers, less than about 150 micrometers (μm) from the nearest VCSEL 200, or in some embodiments, less than about 100 μm, or less than about 50 μm) can shorten the electrical connection 613 between components, thereby reducing parasitic resistance, inductance, and capacitance, and allowing for faster switching response.

[0098] exist Figures 6A to 6CIn the example, the drive transistors 610 are arranged in an array such that each drive transistor 610 is connected in series with a column (or other subset) of VCSELs 200 (or connected anode to cathode), thereby allowing individual control of each column / string of VCSELs 200. However, it should be understood that the embodiments described herein are not limited to this connection configuration. Instead, integrating the drive transistors 610 close to the VCSELs 200 can also allow for more flexible wiring configurations (e.g., series and / or parallel), which can be used to control current and / or improve or maximize performance. For example, fewer or more drive transistors 610 (e.g., drivers for controlling rows and columns of series-connected VCSELs 200) can be provided for better control of the respective VCSELs or groups of VCSELs and / or output power. Another example, compared to some conventional designs (which can be on the order of about 1 to 10 nanoseconds (ns) or longer), is the addition of capacitors or similar electrical storage devices near the elements of the array for faster pulse generation (e.g., on the order of sub-nanoseconds (ns)). Similarly, although shown as a planar array 600, the substrate 607 may be flexible in some embodiments; therefore, similar to Figure 3B The array 300b can be bent to provide the desired curvature of the array 600.

[0099] As discussed similarly to reference arrays 300a and 300b above, array 600 can be scaled based on the desired number or resolution of laser diodes 200, thereby allowing for long-distance and high pulse power output (kilowatt (kW) level). The distribution of laser diodes 200 on the surface of substrate 607 can be selected and / or the operation of the laser diodes can be dynamically adjusted or otherwise controlled (via transistor 610) to reduce optical power density, thereby providing eye safety at long distances and desired operating wavelengths (e.g., approximately 905 nm for GaAs VCSELs and approximately 1500 nm for InP VCSELs). Moreover, the spacing between elements 200 and / or 610 can be selected to provide thermal management and improve heat dissipation during operation. Thus, array 600 described herein can provide improved reliability by eliminating wire bonding, providing a fault-tolerant architecture, and / or providing lower operating temperatures. In other embodiments, see references below. Figures 12A to 12B The discussed possibility is that self-aligned, low-cost beam-shaping micro-optics (e.g., a spherical lens array) can be integrated on or within the surface of array 607.

[0100] Figure 6D It shows Figure 6A A schematic diagram of the equivalent circuit of a distributed transmitter array 600, where transmitter 200 is individually addressable. Figure 6DAs shown, array 600 includes a plurality of VCSEL strings 200 electrically connected in series (or anode-to-cathode) to define columns or other subsets or subarrays of array 600. Array 600 also includes an array of drive transistors 610, wherein each drive transistor 610 is electrically connected in series to a corresponding string of series-connected VCSELs 200. The drive transistors 610 may be individually addressable via a column signal COLUMN. In some embodiments, drive transistors 610 may be individually activated (e.g., biased to conduct), thereby changing the power supplied to the corresponding string of series-connected VCSELs 200. In some embodiments, drive transistors 610 may operate in a linear mode to change the resistance of drive transistors 610 and correspondingly change the current applied to the string of series-connected (or anode-to-cathode connected) VCSELs 200.

[0101] Rows of array 600 can also be individually addressable. For example, array 600 can utilize bypass circuitry to individually select one row from multiple rows of strings of series-connected VCSELs 200. In some embodiments, a corresponding bypass transistor 628 can be used to select a specific VCSEL within the VCSELs 200. For example, to select a specific VCSEL 200 at a particular row and column, a drive transistor 610 for the string containing the specific VCSEL 200 can be activated to provide current flowing through the string, and the bypass transistor 628 associated with the specific VCSEL 200 can be turned off (e.g., biased to be non-conductive) so that current flowing through the string can flow through that VCSEL 200. In some embodiments, the bypass transistor 628 can operate in a linear mode to provide variable resistance along the bypass path. Variable resistance can allow control of the amount of current flowing through the VCSELs 200.

[0102] Figure 6D The circuit embodiments described herein are merely examples of how transmitter array 600 can be configured for both feasible and column-addressable configurations. However, the embodiments described herein are not limited to this particular arrangement. Those skilled in the art will recognize that other possible circuit arrangements are also possible to realize active matrices of devices that can be selectively addressed by row or column, for example, directing a larger proportion of pulse energy to a subset of the VCSEL to modify the far-field pattern of the emitted output beam so that a larger amount of power is received only in certain directions. Such circuit arrangements can be used instead of Figure 6D The circuit layout is provided without departing from the scope of the embodiments described herein.

[0103] Figure 7A This is a perspective view showing a LIDAR device 700a including a surface-emitting laser diode (e.g., VCSEL200) according to an embodiment described herein. Figure 7A It is shown proportionally relative to a pencil. Figure 7C This is a perspective view showing an alternative LIDAR device 700c according to an embodiment described herein. Specifically, Figure 7A and Figure 7C Solid-state flashing LiDAR devices 700a and 700c based on distributed vertical-cavity surface-emitting laser (VCSEL) arrays are shown. A reference curved array 720 (e.g., Figure 3B The curved array 300b) illustrates LIDAR devices 700a and 700c, but it should be understood that LIDAR devices 700a and 700c are not limiting and can be implemented alternatively. Figure 3A Array 300a, Figures 6A to 6C The array 600, and / or other arrays of laser diodes 200 providing the features described herein. Such features of devices 700a, 700c may include, but are not limited to, a wide field of view (in certain embodiments, about θ = 120° in the horizontal direction and φ = 10° in the vertical direction, or wider); long distance (in some cases, greater than about 200 m); compact size with high resolution (in certain embodiments, about 0.1° horizontal and vertical) defined by a reduced size (in certain embodiments, about 110 x 40 x 40 mm); high power (in certain embodiments, about 10,000 W peak, pulsed); and eye safety (in certain embodiments, the dispersed optical power may support eye-safe, high-power, 905 nm (e.g., GaAs) and / or about 1500 nm (e.g., InP) emitters).

[0104] Figure 7B It shows Figure 7A An exploded view of the components of the LIDAR device 700a is shown in diagram 700b. Figure 7B As shown, the device housing or enclosure 701 includes a connector 702 for electrical connection to a power source and / or other external devices. The enclosure 701 is configured to accommodate a light emitter array 720, a photodetector array 730, electronic circuitry 760, detector optics 740 (which may include one or more lenses and / or optical filters), and a lens holder 770. A transparent cover 780 is provided to protect the emitter array 720 and detector optics 740, and in some embodiments may include beam shaping and / or filtering optics.

[0105] The optical emitter array 720 can be a pulsed laser array, such as any of the VCSEL arrays 300a, 300b, and 600 described herein. Thus, the optical emitter array 720 can include a large number (e.g., hundreds or even thousands) of distributed, ultra-small laser diodes 200, collectively configured to provide extremely high levels of power (by leveraging the benefits of a large number of ultra-small devices). Using a large number of small devices rather than a small number of large devices allows for the integration of extremely fast, low-power, and low-temperature operating devices into an optimal configuration (along with other devices, such as transistors, capacitors, etc.) to provide performance not easily obtained with a small number of large laser devices. As described herein, the laser diodes 200 can be simultaneously transferred onto an intrinsically curved or flexible substrate. Beam-shaping optics configured to project high aspect ratio illumination from the optical emitter array 720 onto a target plane can also be disposed on or near the optical emitter array 720.

[0106] The photodetector array 730 may include one or more optical detector devices, such as pin, pinFET, linear avalanche photodiode (APD), silicon photomultiplier tube (SPM), and / or single-photon avalanche diode (SPAD) devices, which are formed of material or otherwise configured to detect light emitted by the light emitter array 720. The photodetector array 730 may include a sufficient number of optical detector devices to achieve the desired sensitivity, fill factor, and resolution. In some embodiments, the photodetector array 730 may be fabricated using a microtransfer process as described herein. Detector optics 740 may be configured to collect high aspect ratio echoes and focus a target image onto the focal plane of the photodetector array 730, and may be held on or near the photodetector array 730 by a lens holder 770.

[0107] Electronic circuitry 760 integrates the above components and other components to provide multiple returned LiDAR point cloud data sets for data analysis. More specifically, electronic circuitry 760 is configured to control the operation of light emitter array 720 and photodetector array 730 to output filtered, high-quality data, such as 3D point cloud data, to one or more external devices via connector 702. External devices can be configured to analyze data provided by LiDAR devices 700a, 700c using proprietary and / or open-source 3D point cloud ecosystems and object classification libraries. For example, such external devices may include those configured for applications including, but not limited to, autonomous vehicles, ADAS, UAVs, industrial automation, robotics, biometrics, modeling, augmented and virtual reality, 3D mapping, and / or security.

[0108] Figure 8 This illustrates some embodiments of a device described herein for use such as Figures 7A to 7CBlock diagram of an example system 800 of LIDAR devices 700a, 700b, and 700c. Figure 8 As shown, system 800 integrates multiple electrically coupled integrated circuit elements to provide the LIDAR device functionality described herein. Specifically, system 800 includes a processor 805 coupled to a memory device 810, an illumination circuit 820, and a detection circuit 830. The memory device 810 stores computer-readable program code therein, which, when executed by the processor, operates the illumination circuit 820 and the detection circuit 830 to collect, process, and output data, such as 3D point cloud data, indicating one or more targets in the operating environment. System 800 may also include a thermistor 842 and associated temperature compensation circuitry 843, as well as power management circuitry 841 configured to regulate the voltage or power supplied to system 800.

[0109] The illumination circuit 820 includes an array of discrete surface-emitting laser diodes 200, a driving transistor 610, and associated circuit elements 611 electrically connected in any of a variety of configurations. In some embodiments, the illumination circuit 820 may be a laser array comprising multiple rows and / or columns of VCSELs 200, such as any of the VCSEL arrays 300a, 300b, and 600 described herein. The processor 805 may control the operation of the illumination circuit 820 to emit light pulses 809 via modulation and timing circuitry 815 to generate pulsed light output 809. Beam shaping and / or focusing optics (e.g., Figures 11A to 14C The lens array shown may also be included in or near the array of laser diodes 200 to shape and / or guide the optical pulses 809.

[0110] Detection circuitry 830 may include a Time-of-Flight (ToF) detector 851 coupled to a Time-of-Flight (ToF) controller 852. The ToF detector 851 may include one or more optical detector devices, such as an array of discrete pins, pin-FETs, linear avalanche photodiodes (APDs), silicon photomultiplier tubes (SPMs), and / or single-photon avalanche diodes (SPADs). The ToF controller 852 may determine the distance to a target by measuring the round-trip time (“time of flight”) of a laser pulse 809′ reflected by the target and received by the ToF detector 851. In some embodiments, the reflected laser pulse 809′ may be filtered by an optical filter 840, such as a bandpass filter, before being detected by the ToF detector 851. The output of detection block 830 may be processed to suppress ambient light before being provided to processor 805, which may perform further processing and / or filtering (identifying filter 817 via a signal processor, and may provide filtered output data (e.g., 3D point cloud data)) for data analysis. Data analysis may include frame filtering and / or image processing. In some embodiments, data analysis may be performed by external devices (e.g., autonomous vehicle intelligent systems).

[0111] Figure 9 This is a cross-sectional view illustrating an example laser diode array 900 including an edge-emitting laser diode 910 according to other embodiments described herein. Figure 9 As shown, the laser diode 910 includes an active region 905 (which may include one or more quantum wells) to generate and emit coherent light 909. The active region 905 is disposed between a p-type layer 901 and an n-type layer 902, and has contacts 912 and 911 thereon, respectively. A diffraction grating layer may be included to provide feedback for lasing. The optical cavity axis of the laser diode 910 is oriented perpendicular to the direction of the current, thereby defining an edge-emitting device such that radiation 909 is emitted from the edge of the device 910 rather than from its top surface. The device 910 can be assembled on an intrinsic substrate 907 by, for example, micro-transfer, electrostatic bonding, or other mass transfer techniques. A corresponding mirror element (shown as a micro-steering mirror 913) can also be assembled on the substrate 907 (e.g., by micro-transfer, electrostatic bonding, or other mass transfer techniques) and oriented relative to the optical cavity axis of the laser diode 910 disposed adjacent thereto, such that radiation 909 from the laser diode 910 is reflected and ultimately emitted in a direction perpendicular to the substrate 907.

[0112] The substrate 907 may be rigid in some embodiments or flexible in others, and the conductive thin-film interconnects may be formed in series and / or parallel configurations electrically connected to corresponding contacts of the laser diode 910, with spacing similar to that described herein with reference to arrays 300a, 300b, and / or 600. Similarly, as referenced above... Figures 6A to 6C As described in the examples, array 900 may include other types of devices and / or devices formed of different materials (e.g., power capacitors, FETs, microlens arrays, etc.), which are integrated with laser diode 910 on substrate 907 at the spacing described herein.

[0113] Other embodiments described herein relate to emitter arrays including beam-shaping structures that can be configured to output arbitrary distributions of light intensity as a function of the field of view using light from a plurality of discrete laser diodes in the array. In some embodiments, the respective laser diodes of the array are arranged on the surface of an intrinsic substrate with different relative orientations, such that coherent light emission from the respective laser diodes is output in different directions (e.g., corresponding to azimuth or elevation) based on the different orientations. The beam-shaping structures according to the embodiments described herein can produce incoherent output light. That is, while the respective light emission from the respective laser diodes is coherent, the output light beam from the array comprises a combination or superposition of corresponding emission that can be incoherent, because the phase of the light emission from one laser diode can be independent of the phase of the light emission from another laser diode. For example, the embodiments described herein may include widening the horizontal and / or vertical field of view, and / or providing local maxima or minima of intensity in a particular direction. In some embodiments, the respective laser diodes can be arranged on an intrinsic substrate with different relative orientations using a micro-transfer process (or other micro-assembly process). Conversely, laser diodes on intrinsic substrates can be defined relative to each other with a fixed or uniform orientation.

[0114] As described herein, some advantages of the incoherent superposition of the emission from the respective laser diodes may include the absence or lack of speckle patterns that could be caused by interference from the monochromatic light emission from the respective laser diodes in the array. Some LiDAR application detection schemes may include incoherent / direct energy detection (which can measure amplitude changes in reflected light) or coherent detection (which can measure Doppler shifts or phase changes in reflected light). Although the main reference is made in which the laser diodes are implemented as surface-emitting laser diodes (e.g., Figures 2A to 2C Embodiments of VCSEL 200 have been described, but it should be understood that, for example... Figures 10A to 15EAs shown, in addition to or in place of the VCSEL 200 shown in the distributed VCSEL array 300 having a beam shaping structure according to the embodiments described herein, edge-emitting laser diodes (e.g., Figure 9 (Edge-emitting laser diode 910 and mirror structure 913).

[0115] Figure 10A This is a perspective view illustrating a distributed emitter array 1000 comprising laser diodes (shown as VCSEL 200) on a curved substrate 1007 according to some embodiments described herein. The curvature of the substrate 1007 provides different orientations for the respective VCSELs 200 of the array 1000 relative to each other, such that their respective laser apertures, optical axes ( Figure 2B In the example, 210 and 208) and coherent light emission are directed in different directions to provide an incoherent output beam 1009. Examples of such methods can be used. Figure 3B The curvature is achieved using a flexible substrate 307b. Some example materials for substrate 1007 may include (but are not limited to) willow glass, thin zirconia (ZrO2) ceramic, thin alumina (Al2O3) ceramic, silicon (Si), metals (aluminum, copper, etc.), and / or plastics / acrylates, wherein said substrate 1007 has sufficient properties to meet reference requirements. Figures 10A to 10D The properties described are curvature or other deformations.

[0116] like Figure 10A As shown, the curvature of substrate 1007 can be controlled according to the embodiments described herein, such that output beam 1009 provides a desired uniform or non-uniform angular power distribution, also referred to herein as intensity distribution (energy per unit area) or photon flux distribution (photons per unit area). The curvature of substrate 1007 may or may not be a constant radius, and can therefore be designed or otherwise selected to provide a desired angular power distribution. For example, substrate 1007 may define a cylindrical, non-cylindrical, spherical, or non-spherical curve on its normal surface to provide a relative power distribution of output beam 1009. Figure 10B The diagram illustrates an example non-uniform angular power distribution 1003 of a beam 1009 that can be output from array 1000. Although the reference azimuth angle θ is... Figure 10B The description is provided, but it should be understood that, depending on the curvature axis of the substrate 1007, the non-uniform angular power distribution 1003 can correspond to the azimuth or elevation angle.

[0117] In order to determine the desired photon flux distribution (e.g., Figure 1The curvature corresponding to the angular power distribution 1003 shown in 0B can define line segments between control points. The line segments can have lengths proportional to the relative power at angles orthogonal to them. The spline can be determined by control point fitting or otherwise defines the profile 1004, for example... Figure 10C As shown in the figure. The defined profile 1004 can define non-spherical or non-cylindrical curves, such as... Figure 10B As shown, its normal surface provides a desired relative power distribution 1003. Thus, the flexible substrate 1007 can be bent or deformed based on the defined profile 1004, for example, as... Figure 10A As shown in the figure. In addition, the VCSEL 200 can be arranged on the intrinsic substrate 1007 with different and / or non-uniform spacing to help provide the desired far-field output light pattern 1009.

[0118] In some embodiments, the curvature of the substrate 1007b can be dynamically changed by mechanical or electromechanical actuation. For example, as Figure 10A As shown, one or more controllable central axes 1050 can be configured to move along the substrate 1007 in one or more motion planes in response to a control signal from a control circuit, such that the placement of the central axis 1050 is configured to deform the substrate 1007 to provide a desired curvature. In some embodiments, the central axis 1050 can be used based on Figure 10C The contour 1004 dynamically bends the flexible substrate 1007 to increase or decrease its curvature, thereby defining the desired aperture shape and Figure 10B The non-uniform angular power distribution 1003 (e.g., more photons output forward than at the edges). Deformation of the substrate 1007 can be dynamically performed in response to changing environmental conditions, allowing for alteration of the field of view covered by light emission from the array 1000. In some embodiments, the central axis 1050 can also serve as a heat sink. Furthermore, as described above, in some embodiments, the spatial density or concentration of VCSELs 200 at the peripheral portion of the array 1000 can be less than that at the central portion of the array 1000.

[0119] refer to Figures 10A to 10C The curvature of the array substrate 1007 shown and described can be based on the desired operating distance and / or direction to provide an output beam 1009 with a larger power distribution in a particular direction or angle, such that greater intensity can provide a larger operating distance. In some embodiments, it may be desirable for a larger operating distance to be straight forward (e.g., corresponding to the forward direction of travel), and the array 1000 may be deformable such that more laser diodes are oriented in the forward direction to provide an output beam 1009 with a larger photon flux distribution in the forward direction compared to directions around the forward travel direction.

[0120] However, in other embodiments described herein, such as... Figure 10D As shown in the diagram, it may be desirable to provide an output beam 1009 with greater intensity to the periphery of array 1000 (e.g., towards the left or right side of array 1000 rather than the center). For example, in some applications, one or more dedicated sensors / sensor arrays may be used for the forward travel direction (e.g., for long-range sensing along a road, where the road may correspond to contour 1006), and array 1000 may be an additional sensor array configured to provide higher resolution in one or more directions around the forward travel direction. Thus, array 1000 can be configured to... Figure 10D The contours 1008a or 1008b shown are bent, which provides a greater angular power distribution to the output beam 1009 in the direction surrounding the straight forward / forward direction of the array 1000. The curvature of the control substrate 1007 in a single dimension (shown as the "horizontal" direction) has been described to provide an angular power distribution that varies over a field of view of up to 180 degrees or more. Figures 10A to 10D Examples of embodiments described herein. However, it should be understood that the curvature control in the embodiments described herein is not limited to a single dimension, and thus some embodiments may include mechanical and / or electromechanical actuators configured to deform the substrate 1007 in multiple dimensions (e.g., in the horizontal or vertical direction), thereby affecting the azimuth (horizontal divergence) and elevation (vertical divergence) of the output beam 1009. Furthermore, in some embodiments, an array of driving transistors (e.g., Figures 6A to 6C The driver transistor 610 can be assembled on the substrate 1007 and is used to dynamically adjust or otherwise control the operating and / or emitter power of corresponding VCSEL 200s or subsets of VCSEL 200s in different regions of the array 1000, to control the angular power distribution individually or in combination with control of the curvature of the substrate 1007. The driver transistor 610 can also be used to sequentially activate columns and / or rows of VCSEL 200s to provide electron beam scanning over the angular power distribution defined by the curvature of the substrate 1007. Furthermore, references herein can be made to... Figures 11A to 14C The described lens arrays 1103a to 1103c, 1203, 1303e, 1403a to 1403c and any of them Figures 15A to 15F The tilted laser diode arrangement is used to control the curvature of the substrate 1107.

[0121] Figure 11A , Figure 11B and Figure 11CThis is a cross-sectional view showing an example distributed emitter array having integrated optical elements 1100a, 1100b, and 1100c, including a shaping microlens array, according to some embodiments described herein, the shaping microlens array being configured for high aspect ratio beam shaping. Figures 11A to 11C As shown, arrays 1100a, 1100b, and 1100c include optical elements in the form of microlens arrays 1103a, 1103b, and 1103c; a plurality of laser diodes (shown as VCSEL 200) assembled in series and electrically connected to define respective rows and / or columns of VCSEL array 300; and conductive interconnects 1113 defining electrical connections between VCSEL 200. VCSEL 200 can be assembled on an intrinsic substrate 1107 (in...) using micro-transfer, electrostatic bonding, or other mass transfer techniques. Figure 11A and Figure 11C (in the middle) or on the surface of the microlens array 1103b (on Figure 11B (in Chinese). For example, microtransfer can achieve VCSEL spacing of less than about 150 micrometers (μm), or in some embodiments, less than about 100 μm or less than about 50 μm, thereby increasing the active region fill factor compared to some conventional VCSEL arrays.

[0122] The substrate 1107 may be rigid or flexible. Some example materials for the substrate 1107 may include (but are not limited to) willow glass, thin zirconia (ZrO2) ceramic, thin alumina (Al2O3) ceramic, silicon (Si), metals (aluminum, copper, etc.) and / or plastics / acrylates, wherein the substrate 1107 has properties sufficient to satisfy the curvature or other deformations described herein.

[0123] The microlens arrays 1103a and 1103c include gaps or interfaces 1180 in the respective emission paths 1190 between the respective lens element 1103e (also referred to herein as microlenses) and the corresponding VCSELs in the VCSEL 200, wherein the corresponding VCSELs in the VCSEL 200 are aligned with the respective lens element 1103e. The interface 1180 may be defined by one or more spacer structures 1106 that attach or otherwise integrate the microlens arrays 1103a and 1103c to the surface of the substrate 1107 and separate the microlens arrays 1103a and 1103c from the surface of the substrate 1107 based on the focal length of the microlens 1103e. In some embodiments, the spacer structures 1106 may be formed of a transparent material such as silicone and may be implemented as spaced-apart spacer structures 1106 defining respective air gaps between them, or as a continuous layer of transparent material filling the space between the VCSEL 200 and the microlens arrays 1103a and 1103c. In some embodiments, the small lens arrays 1103a and 1103c may be formed from glass lens elements or silicone lens elements on glass.

[0124] The light 1109 output from the corresponding VCSEL 200 can be collected by microlenses 1103e of the microlens arrays 1103a and 1103c, resulting in the generation of multiple collimated beams. Collimation can be achieved using microlens arrays 1103a and 1103b with the same spacing as the VCSEL array 300 (i.e., one microlens 1103e for each VCSEL 200). The curvature of the substrate 1107 and / or the microlens arrays 1103a and 1103c can be referenced as above. Figures 10A to 10D As discussed, it is determined and used to provide output light from the array at various angles for the emission of non-collimated beams (e.g., for horizontal and / or vertical divergence). In some embodiments, lens element 1103e may be defined in the surface of small lens arrays 1103a, 1103b, 1103c by molding, casting, embossing and / or etching processes.

[0125] Figure 11BAn example distributed emitter array 1100b according to other embodiments described herein is shown, wherein the VCSEL 200 is directly integrated on the surface of the microlens array 1103b, such that there are no gaps or air interfaces between the respective emission paths 1190 between the respective lens elements 1103e, thereby providing a monolithic microlens / emitter array structure. The thickness of the microlens array 1103b can be selected to effectively serve as a spacing structure throughout the microlens array 1103b to position the VCSEL 200 at or near the focal length of the individual microlenses 1103e. In this way, the surface of the microlens array 1103b serves as an intrinsic substrate. In some embodiments, the microlens array 1103b may be formed of glass lens elements on a silicone layer, or may be formed of silicone alone (e.g., molded silicone), or of a layer of gradient exponential material (providing different refractive indices by varying the loading ratio of high refractive index nanoparticles). That is, the microlens array 1103b can provide an intrinsic substrate for the VCSEL 200.

[0126] Figure 11A and Figure 11B Example microlens arrays 1103a and 1103b are shown, which include plano-convex (PCX) lenses similar to microlens element 1103e, which can provide collimated light output. However, in cases such as Figure 11C In some embodiments shown, the shape of the microlens 1103e can vary independently of each other in one or more directions, such that the output beam 1109 from the lens array 1103c is non-collimated. For example, with reference to the XY plane defined by the surface of the substrate 1107, the shape of the microlens 1103e at the end of the array 1103c can differ in the X direction from that of the microlenses 1103e between them, to provide an output light 1109 with a far-field pattern having a different shape along the x direction (which may correspond to horizontal divergence). Figure 11C The translational symmetry design of the microlens 1103e shown can be used to propagate the output light 1109 in one direction (e.g., the X direction) without affecting propagation in another direction (e.g., the Y direction). However, it should be understood that in order to provide output light 1109 with different shapes along the X-axis and / or Y-axis, the shape of the microlens 1103e can also vary in the Y-direction. More generally, to achieve the desired far-field pattern, the lens prescription can vary on the array 1103c according to the microlens 1103e. The microlens arrays 1103a, 1103b, and 1103c can be formed of flexible lens material, such that the microlens arrays 1103a, 1103b, and 1103c can also be bent or deformed to provide the desired curvature profile, as referenced above. Figures 10A to 10DThe discussion focuses on enabling the output light 1109 from arrays 1100a and 1100b to provide the desired angular power distribution.

[0127] Despite being designed as a single-level design Figures 11A to 11C As described herein, in some embodiments, arrays 1100a, 1100b, and 1100c may include multi-level optical devices, wherein the arrays of optical devices 1103a, 1103b, and 1103c shown are integrated with the array of main optical devices (such as...). Figures 12A to 12B The spherical lens shown is aligned and configured to receive light 1109 from the array of main optics. Such a multi-stage design can provide greater flexibility and performance, for example, by using a first-stage optics in a multi-stage optics setup to provide horizontal divergence of the output light emission and using a next-stage optics setup to provide vertical divergence of the output light emission, or vice versa.

[0128] Figure 12A and Figure 12B This is a cross-sectional view illustrating example distributed emitter arrays 1200a and 1200b with integrated optics including a self-aligned spherical lens array 1203, according to some embodiments described herein, wherein the self-aligned spherical lens array is configured for wide field-of-view beam shaping. Optical alignment of the spherical lenses with a VCSEL can typically utilize active alignment, whereby the spherical lenses can be moved in x, y, and z space while monitoring the far-field pattern for optimal coupling. This alignment process can be slow and expensive, especially for larger VCSEL arrays, which may require tens / hundreds / thousands of spherical lenses to collimate each laser beam emitted by the array.

[0129] Some embodiments described herein can use self-alignment methods to achieve optical alignment between the spherical lens and the VCSEL, for example, using alignment features (e.g., features defined by photolithography) to allow the corresponding spherical lens element 1203e to self-align in x, y, and z space. For example, as Figure 12A and Figure 12BAs shown, arrays 1200a and 1200b include optical elements in the form of: a spherical lens array 1203, a plurality of laser diodes (shown as VCSEL 200) assembled in series and electrically connected to define rows and / or columns of respective plurality of laser diodes (shown as VCSEL 200), and conductive interconnects 1213 defining electrical connections between VCSEL 200. VCSEL 200 can be assembled on intrinsic substrates 1207a and 1207b by micro-transfer, electrostatic bonding, or other mass transfer techniques. Substrates 1207a and 1207b can be rigid or flexible and can be formed from willow glass, thin zirconia (ZrO2) ceramic, thin alumina (Al2O3) ceramic, silicon (Si), metals (aluminum, copper, etc.), and / or plastics / acrylates.

[0130] exist Figure 12B In this embodiment, VCSEL 200 is formed on the back side of substrate 1207b, which is made of a material transparent to the wavelength range of light 1209 emitted by VCSEL 200. Substrate 1207b may have thickness and / or refractive properties that affect the optical path of light output from VCSEL 200, such that lens array 1203 is positioned at a desired focal length. Advantages of this configuration 1200b (also referred to herein as back illumination or bottom illumination) may include protecting VCSEL 200 from or isolating it from processing conditions (e.g., temperature, chemicals, etc.) used in the manufacture of optics 1203. The thickness of substrate 1207b may also contribute to the collimation of light output 1209, for example, because the optical path through the opposing surface of substrate 1207b can provide additional refraction before entering lens element 1203e. In other embodiments, the substrate 1207b may have sufficient thickness and / or refractive properties to provide collimation of the light output 1209 without the need for other lens elements 1203e (i.e., the lens array 1203 is not required).

[0131] exist Figure 12A and Figure 12B In this embodiment, the non-intrinsic substrates 1207a and 1207b also include alignment features 1206a and 1206b on their surfaces. The spacing between the alignment feature pairs 1206a and 1206b can be adjusted and configured to suspend the respective spherical lens elements 1203e above the respective VCSEL 200, such that the respective optical axis of each spherical lens element 1202e is aligned with the optical axis defined by the laser aperture of the underlying VCSEL 200.

[0132] In some embodiments, the spherical lens elements 1203e may each have a corresponding diameter of about 250 μm or less to be compatible with the size of the VCSEL-based VCSEL array 300 described herein. To achieve precise alignment between such small spherical lens elements 1203 and the optical axis of the VCSEL 200 described herein, in some embodiments, alignment features 1206a and 1206b may be defined by photolithography. For example, alignment features 1206a and 1206b may be formed from a dry film resist layer that is photolithographically patterned to define apertures therein, wherein the apertures are sized and shaped to align the optical axis of the spherical lens elements 1203e of a predetermined radius with the optical axis defined by the corresponding apertures of the VCSEL 200. However, it should be understood that some applications (e.g., flash LIDAR) can tolerate the absence or imperfection of optical axis alignment of the individual lenses 1203e / VCSEL 200 in the hundreds or thousands of lenses 1203e / VCSEL 200 in arrays 1200a and 1200b, and that other materials can be used to define the alignment features 1206a and 1206b.

[0133] The sizes of alignment features 1206a and 1206b can be adjusted to define sufficient gaps between each spherical lens element 1203e and the underlying VCSEL 200 to provide desired collimation of the light 1209 emitted from the underlying VCSEL 200. Different materials can be selected for alignment features 1206a and 1206b, either alone or in combination with additional features for supporting the spherical lenses, based on the size of the desired gaps (and the corresponding heights of alignment features 1206a and 1206b). In some embodiments, a transparent material can fill the gaps between the lens element 1203e and the underlying VCSEL 200 (or similarly, the gaps between the lens arrays 1103a, 1103c and the VCSEL 200). For example, the gaps can be air, silicone, or other materials transparent to the wavelength range of the light 1209 emitted by the VCSEL 200.

[0134] Some of the embodiments described herein may have greater benefits in applications including ultra-large arrays 1200a, 1200b on ultra-small dies, where the spherical lens 1203e has a diameter of less than about 250 μm, for example in LiDAR applications. In some embodiments, microtransfer (MTP) can be used to print the pre-aligned array 1203 of the spherical lens 1203e onto the VCSEL array 300. In other embodiments, BGA technology can be used for pre-alignment, wherein the spherical lens 1203e can be pre-aligned by casting the spherical lens 1203e onto a grid that has been photolithographically generated to define the spherical lens array 1203, and the MTP die can pick up the spherical lens array 1203 from the pre-aligned grid and deposit the spherical lens array 1203 onto the top of the VCSEL array 300 such that the spherical lens 1203e is aligned by alignment features 1206a, 1206b. In some embodiments, to further modify the field of view (e.g., the vertical divergence of the light output 1209), Figure 12A and Figure 12B The spherical lens array 1203 can be used with the lens array above (e.g., Figures 14A to 14C It is used in conjunction with Fresnel lens 1403.

[0135] Figure 13A and Figure 13B This is a cross-sectional view of example distributed emitter arrays having integrated optics 1300a, 1300b, and 1300c, including an array of offset spherical lenses for beam shaping, according to some embodiments described herein. Figure 13C This is a perspective view showing this example distributed transmitter array. (As shown) Figures 13A to 13C As shown, arrays 1300a, 1300b, and 1300c include optical elements in the form of a spherical lens array, a plurality of laser diodes (shown as VCSEL 200) assembled in series and electrically connected to define respective rows and / or columns of VCSEL array 300, and conductive interconnects 1313 defining electrical connections between VCSEL 200. VCSEL 200 can be assembled on intrinsic substrates 1307a, 1307b, and 1307c by micro-transfer, electrostatic bonding, or other mass transfer techniques. Substrates 1307a, 1307b, and 1307c may be rigid in some embodiments or flexible in others.

[0136] like Figures 13A to 13C As shown, each lens element 1303e of the lens array is suspended above a plurality of VCSELs 200, such that the light emission direction from each VCSEL 200 is offset relative to the optical axis of the corresponding lens element 1303e. For example, as in Figure 13A and Figure 13BAs shown in the enlarged cross-sectional view, the extrinsic substrates 1307a and 1307b include alignment features 1306a and 1306b on their surfaces, wherein the spacing between the alignment feature pairs 1306a and 1306b is sized and configured to suspend corresponding spherical lens elements 1303e above the 2x2 subarray of the VCSEL 200, such that the optical axis of each spherical lens element 1303e is misaligned with the corresponding optical axis defined by the laser aperture of the underlying VCSEL 200, and the lens element 1303e diffracts the light emitted from the underlying VCSEL 200 into the non-collimated beam 1309.

[0137] and Figures 12A to 12B Compared to the aligned lens elements, the reference beam 1309 has increased horizontal and vertical divergence. Figures 13A to 13C Examples are illustrated below. In some embodiments, substrates 1307a, 1307b, and 1307c may be bent to provide further horizontal and / or vertical divergence. For example, substrates 1307a, 1307b, and 1307c may (but are not limited to) be formed of willow glass, thin zirconia (ZrO2) ceramic, thin alumina (Al2O3) ceramic, silicon (Si), metals (aluminum, copper, etc.), and / or plastics / acrylates. Figure 13B In one embodiment, the substrate is formed of a material that is transparent to the wavelength range of the light 1309 emitted by the VCSEL 200. The substrate 1307b may have thickness and / or refractive properties that affect the optical path of the light output from the VCSEL 200, such that the lens element 1303e is positioned at the desired focal length.

[0138] exist Figure 13C In the example, array 1300c also includes integrated driver transistors 1310, wherein the integrated driver transistors 1310 are assembled adjacent to one or more VCSEL 200s on substrate 1307c using a microtransfer (MTP) process. For example, array 1300c includes a plurality of 2x2 subarrays of monolithic VCSEL 200s electrically connected in series (or, anode to cathode) to define columns or other subsets of array 1300c. Array 1300c also includes an array of driver transistors 1310, wherein each driver transistor 1310 is electrically connected in series with a corresponding column (or other subset) of the 2x2 subarray of VCSEL 200. Driver transistors 1310 can also be used to sequentially activate columns and / or rows of VCSEL 200 to provide electron beam scanning. Additionally, the integration of the array of driver transistors 1310 with the subarrays of VCSEL 200 can also be similar to... Figures 6A to 6C The array is 600, therefore no further description will be provided.

[0139] In some embodiments, in order to further modify the field of view (e.g., the vertical divergence of the light output 1309), Figures 13A to 13C The spherical lens array can be combined with the lens array above (e.g., Figures 14A to 14C It is used in conjunction with Fresnel lens 1403.

[0140] Figure 14A , Figure 14B and Figure 14C This is a cross-sectional view of an example distributed emitter array having integrated optical elements 1400a, 1400b and 1400c including a lens array, according to some embodiments described herein, wherein the lens array has a primary lens element and / or an auxiliary lens element configured for multi-directional beam shaping. Figure 14A The array 1400a includes a plurality of laser diodes (shown as VCSEL 200) assembled in string and electrically connected to define respective rows and / or columns of the VCSEL array 300, and conductive interconnects 1413 defining electrical connections between the VCSEL 200. The VCSEL 200 can be assembled on an intrinsic substrate 1407 by micro-transfer, electrostatic bonding, or other mass transfer techniques. The substrate 1407 can be rigid or flexible and can be (but is not limited to) formed of willow glass, thin zirconia (ZrO2) ceramic, thin alumina (Al2O3) ceramic, silicon (Si), metals (aluminum, copper, etc.), and / or plastics / acrylates.

[0141] Figure 14A The embodiments include a main lens array 1403a, which includes corresponding lens elements 1403e suspended above corresponding VCSELs 200 by alignment features 1406. The size and spacing of the alignment features 1406 are adjusted and configured to align the corresponding optical axis of each lens element 1403e with the optical axis defined by the laser aperture of the underlying VCSEL 200. In some embodiments, the lens element 1403e may be a spherical lens (e.g., a ball lens), or in some embodiments, a cylindrical lens. The lens elements 1403e of the main lens array 1403a may be configured to increase the azimuth angle (horizontal divergence) of the output beam 1409 from the array 1400a.

[0142] Still referencing Figure 14A Array 1400a also includes an auxiliary array 1404a (shown as Fresnel lenses). The auxiliary lens array 1404a is configured to increase the elevation angle (vertical divergence) of the output beam 1409 while substantially maintaining horizontal beam divergence (e.g., less than 1 degree per column). Figure 14AIn the example, the auxiliary lens array 1404a is implemented as a thin, flexible linear Fresnel lens cap (including corresponding Fresnel microlenses 1404e) to vertically diverge the emitted light from each VCSEL 200 by approximately 15 degrees to approximately 26 degrees, wherein the thin, flexible linear Fresnel lens cap is disposed above the VCSEL array 300 and the primary lens array 1403a thereon. In embodiments where the substrate 1407 is formed of a flexible material, the array 1400a can also be bent to achieve an overall horizontal field of view (FoV) of up to approximately 150 degrees or greater. However, the auxiliary lens element 1404a is not limited to Fresnel lenses; for example, in some embodiments, the auxiliary lens element 1404a can be implemented by a flexible diffuser film.

[0143] Thus, in some embodiments, a corresponding spherical lens 1403e can be used to horizontally collimate the light from each VCSEL 200 to approximately 0.1 degrees per column. In other embodiments, a cylindrical lens element 1403e can be used to collimate the light from each column of the VCSEL 200 in the array 300 to provide approximately 0.1 degrees of horizontal collimation. That is, Figure 14A The array 1400a uses a combination of primary lens elements (e.g., spherical or cylindrical lens 1403e) and secondary lens elements (e.g., Fresnel lens 1404a) to control the horizontal and vertical divergence of the output laser beam 1409 from the respective VCSEL 200.

[0144] Alignment features 1406 for self-aligning the lens element 1403e (whether spherical or cylindrical) can be defined by photolithography, for example, from a dry film resist layer patterned to define holes (for spherical lenses 1403e) or grooves (for cylindrical lenses 1403e). However, in other embodiments, the primary lens array 1403a can be omitted; for example, the secondary lens array 1404a can provide vertical divergence of the output beam 1409, while horizontal divergence is provided by the curvature of the substrate 1407.

[0145] exist Figure 14A In one embodiment, the auxiliary lens array 1404a includes corresponding Fresnel microlenses 1404e, each Fresnel microlens 1404e having an optical axis aligned with the optical axis of the underlying main lens element 1403e and VCSEL 200. Figure 14B An alternative configuration of a distributed transmitter array with integrated optics 1400b is shown, comprising a large-area Fresnel lens array 1404b overlying the entire array 300 of VCSELs 200. That is, each VCSEL 200 is located beneath a different region of a single Fresnel aperture 1404b. Figure 14BIn the example, lens element 1403e is omitted. Thus, the large-area Fresnel lens array 1404b can provide vertical divergence of the output beam 1409, while horizontal divergence is provided by the curvature of the substrate 1407. In some embodiments, lens 1404b can be a flexible (e.g., plastic) Fresnel lens. Moreover, as mentioned above, lens array 1404b is not limited to Fresnel lens arrays and in some embodiments can be implemented using a flexible diffuser film.

[0146] Another embodiment of a distributed transmitter array with integrated optics 1400c is in Figure 14C As shown, in order to achieve the desired far-field pattern of the output beam 1409, multi-layer lens arrays 1403c and 1404c (shown as corresponding large-area Fresnel lenses) are used sequentially. Figure 14C In the example, lens array 1403c is used to influence the angle of laser emission in one dimension (e.g., horizontal divergence in the X direction along the surface of substrate 1407), while lens array 1404c is used to influence the angle of laser emission in another dimension (e.g., vertical divergence in the Y direction along the surface of substrate 1407), and vice versa. That is, arrays 1400a and 1400c include stacked lens array structures, whereby the first lens elements 1403a and 1403c change the far-field pattern of the output beam 1409 in the first dimension, while the second lens elements 1404a and 1404c change the far-field pattern of the output beam 1409 in the first dimension.

[0147] Although the embodiments of reference lens arrays 1403c, 1404a to 1404c and VCSEL 200 stacked on the surface of substrate 1407 are in... Figures 14A to 14C As described herein, it should be understood that in some embodiments, substrate 1407 is transparent to the wavelength range of light emitted from VCSEL 200, and VCSEL 200 can be arranged such that light can be transmitted through a transparent substrate (e.g., Figure 12B and Figure 13B (As shown in the diagram) to reach lens arrays 1403c, 1404a to 1404c.

[0148] It also mainly referenced the array pairs of Fresnel lenses 1404a, 1404b, 1403c, and 1404c. Figure 14A and Figure 14C As initially described, Fresnel lenses 1404a, 1404b, 1403c, and 1404c can be formed of a material with sufficient physical flexibility to be integrated with the flexible substrate 1407, thereby allowing integration similar to that described above. Figures 10A to 10DThe curvature of arrays 1400a, 1400b, and 1400c is adjusted in the manner described herein. However, it should be understood that the embodiments described herein are not limited to this Fresnel lens array, and other flexible optical elements and / or microlenses can be used to influence the far-field pattern of the output beam 1409 by scattering light from the laser diode 200. For example, one or more of the lens arrays 1404a, 1404b, 1403c, and 1404c can be implemented using incoherent micro-optical scattering diffusers, such as those fabricated by Brightview Technologies and Luminit. The embodiments described herein can utilize these and / or other optical elements to modify the far-field pattern of VCSEL arrays, for example, in LiDAR applications.

[0149] and Figure 14E Compared to the absence of such an optical diffuser, in Figure 14D The diagram illustrates how flexible optical diffusers on a VCSEL array provide the output beam to modify the field of view (FOV). The arrangement of these optical diffusers can be similar to... Figures 14A to 14C The arrangement, in which optical diffusers replace the Fresnel lens arrays 1404a, 1404b, 1403c, and 1404c shown. (As...) Figure 14D As shown, the optical diffuser can significantly widen the elevation angle coverage, compared to Figure 14E Compared to the elevation beam profile 1409e shown, the increase in the half-width at half-maximum (FWHM) of the elevation beam profile 1409e' for the output beam 1409 is shown. Also as Figure 14D As shown, the FWHM of the azimuth beam profile 1409a' of the output beam 1409 remains relatively unchanged due to the optical diffuser, as... Figure 14E The azimuth beam profile 1409a in the image is similar to that shown in FWHM.

[0150] In other words, although relative to Fresnel-type lens elements that provide vertical divergence... Figures 14A to 14C While this has been described, it should be understood that other types of lens elements may be integrated above the surface of the emitter array 300 to provide vertical beam divergence, either in conjunction with or independently of a lens array configured to provide horizontal beam divergence (e.g., where the curvature of the substrate 1407 provides horizontal beam divergence). More generally, Figures 14A to 14C The embodiments may use any combination of the curvature of the substrate 1407, the primary lens elements 1403a, 1403c, and the secondary lens elements 1404a, 1404b, 1404c to provide horizontal and / or vertical divergence of the output beam 1409.

[0151] Figure 15A , Figure 15B , Figure 15C , Figure 15E and Figure 15F This is a cross-sectional view of portions of example distributed emitter arrays 1500a, 1500b, 1500c, 1500e and 1500f, including tilted laser diodes for lensless beam shaping, according to some embodiments described herein. Figure 15D It shows Figure 15C A plan view of a portion of the array 1500c.

[0152] like Figures 15A to 15E As shown, laser diodes (shown as VCSEL chiplets 200) are assembled on a rigid or flexible intrinsic target substrate 1507 using micro-transfer, electrostatic bonding, or other mass transfer techniques. The VCSEL chiplets 200 can be electrically connected in series to define corresponding rows and / or columns of the emitter array via conductive interconnects to anode contact 211 and cathode contact 212, as shown. Figure 2A and Figure 2B As shown, the anode contact 211 and cathode contact 212 are smaller than their corresponding laser apertures in at least one dimension. Conductive interconnects can be formed by patterning conductive films after the VCSEL chiplet 200 is disposed on the substrate 1507, for example using conventional photolithography techniques instead of combining wire bonds, strips, cables, or leads. In some embodiments, a die with a planar or serrated surface can be used to pick up the VCSEL chiplet 200 from the source substrate or wafer (e.g., in a manner similar to...). Figures 4A to 4F as well as Figures 4A' to 4G' (method); and printing the VCSEL chip 200 on the target substrate 1507.

[0153] Still referencing Figures 15A to 15E The VCSEL chiplet 200 can be oriented differently by one or more physical features 1506a to 1506e on the substrate 1507, such that the optical axis defined by their respective laser apertures 210 has a corresponding tilt angle θ relative to the direction orthogonal to the surface of the substrate 1507. For example... Figure 15E As shown, in some embodiments, the substrate 1507 may include a patterned or structured surface 1506e, such that the VCSEL chiplets 200 are angled to provide a corresponding tilt angle θ deposited on the surface 1506e. Figures 15A to 15D As shown, different heights H A and H BThe track-shaped or strip-shaped features 1506a and 1506b can be deposited on the substrate 1507 and spaced apart by a distance sufficient to angle the VCSEL chiplets 200 to provide a corresponding tilt angle θ when deposited on the substrate. An underfill material (e.g., an adhesive layer) can be disposed between each VCSEL 200 and the underlying substrate features 1506a to 1506e to improve adhesion, electrical contact, and / or, in some embodiments, to pull the VCSEL 200 toward the surface of the non-intrinsic substrate 1507.

[0154] VCSEL chips 200 can be printed such that their corresponding laser apertures 210 point away from the substrate 1507, such as... Figure 15A as well as Figures 15C to 15E As shown, this directs the output beam 1509 away from the substrate 1507. Alternatively, as... Figure 15B As shown, the substrate 1507 may be transparent, and the VCSEL chips 200 may be printed inverted such that their laser apertures 210 point towards the substrate 1507, and that the laser apertures 210 guide light between the strip features 1506a, 1506b to provide an output beam 1509 through the substrate 1509, also referred to herein as bottom illumination. In some embodiments of bottom illumination, the space between the VCSEL chips 200 and the substrate 1507 may be bottom-filled with a transparent material, such as silicone, to provide refractive index matching.

[0155] exist Figures 15A to 15D In this process, VCSEL chiplets 200 are deposited onto substrates with different heights (H). A and H B The rail or strip features on 1506a and 1506b define corresponding tilt angles (θ) relative to the surface of substrate 1507. The spacing (P) and / or height (H) of the strip features 1506a and 1506b can be selected. A and H B The relative difference between the two stripe features 1506a and 1506b is used to change the tilt angle θ for each VCSEL chiplet 200. That is, one or more stripe feature pairs 1506a and 1506b can have different relative heights and / or spacings compared to other stripe feature pairs 1506a and 1506b on the same target substrate 1507. For example, as... Figure 15C and Figure 15DAs shown, a platform feature 1506c may be disposed between at least one of the strip features 1506a and 1506b and the surface of the substrate 1507 to increase the relative height difference between them. In some embodiments, strip features 1506a and 1506b may be elements of equal height, wherein the height difference is provided by strip features 1506b stacked on the platform feature 1506c. The surface of the target substrate 1507 may be patterned or otherwise defined to include a recessed feature 1506d, which may be sized and oriented to accommodate the lower corner of the tilted VCSEL 200. Features 1506a to 1506c may be formed using conductive and / or non-conductive materials with semiconductor processes. For example, strip features 1506a and 1506b may be linear features patterned with metal or photoresist of different thicknesses. In some embodiments, multilayer materials may be used to construct the thickness of strip features 1506a and 1506b. In some embodiments, features 1506a, 1506b, and 1506c can be micro-transfer-printed onto the surface of substrate 1507. Therefore, VCSEL 200s printed or otherwise deposited on these varying height / spacing stripe feature pairs 1506a and 1506b can define an array of discrete VCSEL 200s with varying orientations and emission angles, thereby providing a wider field of view / illumination.

[0156] Although the discussion primarily refers to the tilt orientation to provide a dimensional divergence (e.g., elevation / vertical divergence, while azimuth / horizontal divergence is provided by the curvature of the flexible substrate 1507), it should be understood that features 1506a to 1506e can be oriented at different corresponding angles (rather than in the grid) such that each tilted VCSEL 200 has a horizontal divergence component and a vertical divergence component, both of which can be further amplified by the curvature of the substrate 1507 along the corresponding dimension.

[0157] In addition, although referencing the VCSEL chiplet 200 in Figures 15A to 15E The description is provided, but it should be understood that the tilted emitter structure according to some embodiments described herein can be implemented using an edge-emitting laser diode 910, such as... Figure 15F An example distributed transmitter array 1500f is shown. Figure 15FIn this process, an edge-emitting laser diode 910 is printed or otherwise deposited on a flat portion of the surface of substrate 1507, and a micro-steering mirror structure 913 is printed or otherwise deposited at an angle on strip features 1506a and 1506b, such that the output beam 1509 is reflected to provide a corresponding tilt angle θ; however, it should be understood that one or both of the laser diode 910 and the mirror structure 913 can be deposited on any combination of physical features 1506a to 1506e on substrate 1507 to provide the desired corresponding tilt angle θ.

[0158] The invention has been described above with reference to the accompanying drawings, which illustrate embodiments of the invention. However, the invention should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the thicknesses of the layers and regions are enlarged for clarity. Throughout the drawings, similar reference numerals refer to similar elements.

[0159] It should be understood that when an element is referred to as being "on" another element, "connected" to, or "coupled" to another element, it can be directly connected to or coupled to that other element, or there can be an intermediate element. Conversely, when an element is referred to as being "directly on" another element, "directly connected" to, or "directly coupled" to that other element, there is no intermediate element.

[0160] It should also be understood that although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish elements from one another. For example, a first element may be referred to as a second element without departing from the scope of the invention, and similarly, a second element may be referred to as a first element.

[0161] Furthermore, relative terms such as “down” or “bottom” and “up” or “top” may be used herein to describe the relationship between one element and another shown in the figures. It should be understood that, in addition to the orientations depicted in the figures, the relative terms are intended to cover different orientations of the device. For example, if a device in a figure is flipped, an element described as being “down” to another element will be oriented “up” to that element. Thus, the exemplary term “down” can cover both “down” and “up” orientations, depending on the specific orientation of the figure. Similarly, if a device in a figure is flipped, an element described as being “below” or “under” to another element will be oriented “above” to that element. Thus, the exemplary term “below” or “under” can cover both “up” and “down” orientations.

[0162] The terminology used herein to describe the invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used in the description of the invention and the appended claims are also intended to include the plural forms. It should also be understood that the term “and / or” as used herein refers to and covers any and all possible combinations of one or more of the associated listed items. It should also be understood that the terms “having,” “containing,” “comprising,” and / or “including” as used in this specification indicate the presence of the described features, integrals, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof.

[0163] Embodiments of the invention are described herein with reference to illustrations, which are schematic diagrams of ideal embodiments (and intermediate structures) of the invention. Therefore, variations in the illustrated shapes are expected, for example, due to manufacturing techniques and / or tolerances. Consequently, the areas shown in the figures are schematic in nature, and their shapes are not intended to represent the actual shapes of areas of the device, nor are they intended to limit the scope of the invention.

[0164] Unless otherwise specified, all terms used to disclose embodiments of the present invention, including technical and scientific terms, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and are not necessarily limited to the specific definitions known at the time of the description of the invention. Therefore, these terms may include equivalent terms created after that time. It should also be understood that terms such as those defined in common dictionaries should be interpreted as having the meaning consistent with their meaning in the context of this specification and related art, and should not be interpreted as having an ideal or overly formal meaning, unless expressly defined herein. All publications, patent applications, patents, and other references mentioned herein are incorporated herein by reference in their entirety.

[0165] In conjunction with the foregoing description and accompanying drawings, numerous different embodiments are disclosed herein. It should be understood that a verbatim description and illustration of each combination and sub-combination of these embodiments would be overly redundant and obscure. Therefore, this specification, including the accompanying drawings, will be interpreted as a complete written description of all combinations and sub-combinations of the embodiments of the invention described herein, as well as the ways and processes of making and using them, and will support the claim to any such combination or sub-combination.

[0166] Although the invention has been described herein with reference to various embodiments, it should be understood that further changes and modifications can be made within the scope and spirit of the invention. While specific terminology has been used, it is used in a general and descriptive sense only and not for limiting purposes; the scope of the embodiments of the invention is set forth in the appended claims.

Claims

1. A flash LIDAR device, comprising: An array of corresponding laser diodes, arranged and electrically connected to each other in the flash LIDAR device, provides coherent light emission in different directions, and the flash LIDAR device is configured to emit an output beam comprising coherent light emission from each corresponding laser diode in the electrically connected array of laser diodes. The corresponding phases of the coherent light emission from the respective laser diodes are independent of each other, and the output beam comprises a superposition of coherent light emission from the respective laser diodes, the superposition defining an incoherent output beam from the array of respective laser diodes having a non-uniform intensity distribution in the field of view of the flash LIDAR device.

2. The flash LIDAR device of claim 1, wherein the respective laser diode is disposed on an intrinsic substrate, the intrinsic substrate comprising curvature providing different orientations for the respective laser diode.

3. The flash LIDAR device of claim 2, wherein the intrinsic substrate is a flexible substrate that is bent to define the curvature of the intrinsic substrate.

4. The flash LIDAR device of claim 3, wherein the non-uniform intensity distribution is controllable in response to a control signal for changing the curvature of the flexible substrate and / or in response to the power supplied to the respective laser diodes via selective addressing.

5. The flash LIDAR device of claim 1, wherein the corresponding laser diode is disposed on the back side of an intrinsic substrate, wherein the corresponding laser diode is arranged to provide coherent light emission through the intrinsic substrate, and wherein the intrinsic substrate comprises a material that is transparent to the coherent light emission and configured to collimate the coherent light emission at least partially.

6. The flash LIDAR device of claim 1, wherein corresponding features on the surface of the non-intrinsic substrate provide different orientations of the corresponding laser diodes.

7. The flash LIDAR device of claim 6, wherein the corresponding feature includes uneven height features and / or recesses, the size and spacing of the uneven height features and / or recesses being configured to provide different orientations of the corresponding laser diodes.

8. The flash LIDAR device of claim 7, wherein the corresponding feature includes a corresponding patterned surface of the intrinsic substrate.

9. The flash LIDAR device of claim 1, wherein the flash LIDAR device is configured to emit the output beam without refractive optics.

10. The flash LIDAR device according to claim 1, further comprising: A lens configured to alter the divergence of the output beam in at least one dimension.

11. The flash LIDAR device of claim 10, wherein the lens comprises a flexible material and / or a curvature corresponding to different orientations of the respective laser diode.

12. The flash LIDAR device of claim 10, wherein the lens comprises: A main lens, the main lens being configured to change the divergence of the output beam in a first direction; And an auxiliary lens, which is arranged to receive the output beam from the main lens and change the divergence of the output beam in a second direction.

13. The flash LIDAR device of claim 10, wherein the lens comprises at least one of the following: a Fresnel lens, a plurality of shaping microlenses, an optical diffuser, or a plurality of spherical lenses.

14. The flash LIDAR device of claim 11, wherein the lens comprises a microlens array defining a plurality of micro-optical channels, each micro-optical channel comprising a corresponding micro-optical lens spaced apart from a corresponding laser diode among a plurality of laser diodes.

15. The flash LIDAR device of claim 1, wherein the corresponding laser diode is a vertical cavity surface-emitting laser (VCSEL), wherein the corresponding electrical contact to the VCSEL is smaller than the corresponding laser aperture of the VCSEL in at least one dimension, and wherein the VCSEL does not have a wire bonding pad electrically connected to the corresponding electrical contact.

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