Devices and methods for a rotating LIDAR platform with a shared transmit/receive path

id="REI-00001" date="20220104"

CROSS REFERENCE

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id="REI-00002" date="20220104"

CROSS-REFERENCE

id="REI-00002"

TO RELATED

id="REI-00003" date="20220104"

APPLICATION

id="REI-00003"

id="REI-00004" date="20220104"

APPLICATIONS

id="REI-00004"

The present applicationNOTICE: More than one reissue application has been filed for the reissue of U.S. Pat. No. 9,285,464 B2. The reissue applications are U.S. Reissue patent application Ser. No. 16/890,789 (the present application), filed on Jun. 2, 2020, which is a continuation reissue application of U.S. Reissue patent application Ser. No. 15/919,479, filed on Mar. 13, 2018, now U.S. Reissue Pat. No. 48,042 E, issued Jun. 9, 2020, which is a reissue application of U.S. patent application Ser. No. 14/462,075, filed on Aug. 18, 2014, now U.S. Pat. No. 9,285,464 B2, issued Mar. 15, 2016, which is a continuation of U.S. patent application Ser. No. 13/971,606, filed on Aug. 20, 2013, which application isnow U.S. Pat. No. 8,836,922, issued Sep. 16, 2014, all of which are herein incorporated herein by reference as if fully set forth in this description.

BACKGROUND

Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.

Vehicles can be configured to operate in an autonomous mode in which the vehicle navigates through an environment with little or no input from a driver. Such autonomous vehicles can include one or more sensors that are configured to detect information about the environment in which the vehicle operates.

One such sensor is a light detection and ranging (LIDAR) device. A LIDAR can estimates distance to environmental features while scanning through a scene to assemble a “point cloud” indicative of reflective surfaces in the environment. Individual points in the point cloud can be determined by transmitting a laser pulse and detecting a returning pulse, if any, reflected from an object in the environment, and determining the distance to the object according to the time delay between the transmitted pulse and the reception of the reflected pulse. A laser, or set of lasers, can be rapidly and repeatedly scanned across a scene to provide continuous real-time information on distances to reflective objects in the scene. Combining the measured distances and the orientation of the laser(s) while measuring each distance allows for associating a three-dimensional position with each returning pulse. In this way, a three-dimensional map of points indicative of locations of reflective features in the environment can be generated for the entire scanning zone.

SUMMARY

In one example, a light detection and ranging (LIDAR) device is provided that includes a housing configured to rotate about an axis. The housing has an interior space that includes a transmit block, a receive block, and a shared space. The transmit block has an exit aperture and the receive block has an entrance aperture. The LIDAR device also includes a plurality of light sources in the transmit block. The plurality of light sources is configured to emit a plurality of light beams that enter the shared space through the exit aperture and traverse the shared space via a transmit path. The light beams include light having wavelengths in a wavelength range. The LIDAR device also includes a plurality of detectors in the receive block. The plurality of detectors is configured to detect light having wavelengths in the wavelength range. The LIDAR device also includes a lens mounted to the housing. The lens is configured to (i) receive the light beams via the transmit path, (ii) collimate the light beams for transmission into an environment of the LIDAR device, (iii) collect light that includes light from one or more of the collimated light beams reflected by one or more objects in the environment of the LIDAR device, and (iv) focus the collected light onto the detectors via a receive path that extends through the shared space and the entrance aperture of the receive block.

In another example, a method is provided that involves rotating a housing of a light detection and ranging (LIDAR) device about an axis. The housing has an interior space that includes a transmit block, a receive block, and a shared space. The transmit block has an exit aperture and the receive block has an entrance aperture. The method further involves emitting a plurality of light beams by a plurality of light sources in the transmit block. The plurality of light beams enter the shared space via a transmit path. The light beams include light having wavelengths in a wavelength range. The method further involves receiving the light beams at a lens mounted to the housing along the transmit path. The method further involves collimating, by the lens, the light beams for transmission into an environment of the LIDAR device. The method further involves collecting, by the lens, light from one or more of the collimated light beams reflected by one or more objects in the environment of the LIDAR device. The method further involves focusing, by the lens, the collected light onto a plurality of detectors in the receive block via a receive path that extends through the shared space and the entrance aperture of the receive block. The method further involves detecting, by the plurality of detectors in the receive block, light from the focused light having wavelengths in the wavelength range.

These as well as other aspects, advantages, and alternatives, will become apparent to those of ordinary skill in the art by reading the following detailed description, with reference where appropriate to the accompanying figures.

BRIEF DESCRIPTION OF THE FIGURES

<figref idref="DRAWINGS">FIG. 1</figref> is a block diagram of an example LIDAR device.

<figref idref="DRAWINGS">FIG. 2</figref> is a cross-section view of an example LIDAR device.

<figref idref="DRAWINGS">FIG. 3A</figref> is a perspective view of an example LIDAR device fitted with various components, in accordance with at least some embodiments described herein

<figref idref="DRAWINGS">FIG. 3B</figref> is a perspective view of the example LIDAR device shown in <figref idref="DRAWINGS">FIG. 3A</figref> with the various components removed to illustrate interior space of the housing.

<figref idref="DRAWINGS">FIG. 4</figref> illustrates an example transmit block, in accordance with at least some embodiments described herein.

<figref idref="DRAWINGS">FIG. 5A</figref> is a view of an example light source, in accordance with an example embodiment.

<figref idref="DRAWINGS">FIG. 5B</figref> is a view of the light source of <figref idref="DRAWINGS">FIG. 5A</figref> in combination with a cylindrical lens, in accordance with an example embodiment.

<figref idref="DRAWINGS">FIG. 5C</figref> is another view of the light source and cylindrical lens combination of <figref idref="DRAWINGS">FIG. 5B</figref>, in accordance with an example embodiment.

<figref idref="DRAWINGS">FIG. 6A</figref> illustrates an example receive block, in accordance with at least some embodiments described herein.

<figref idref="DRAWINGS">FIG. 6B</figref> illustrates a side view of three detectors included in the receive block of <figref idref="DRAWINGS">FIG. 6A</figref>.

<figref idref="DRAWINGS">FIG. 7A</figref> illustrates an example lens with an aspheric surface and a toroidal surface, in accordance with at least some embodiments described herein.

<figref idref="DRAWINGS">FIG. 7B</figref> illustrates a cross-section view of the example lens <b>750</b> shown in <figref idref="DRAWINGS">FIG. 7A</figref>.

<figref idref="DRAWINGS">FIG. 8A</figref> illustrates an example LIDAR device mounted on a vehicle, in accordance with at least some embodiments described herein.

<figref idref="DRAWINGS">FIG. 8B</figref> illustrates a scenario where the LIDAR device shown in <figref idref="DRAWINGS">FIG. 8A</figref> is scanning an environment that includes one or more objects, in accordance with at least some embodiments described herein.

<figref idref="DRAWINGS">FIG. 9</figref> is a flowchart of a method, in accordance with at least some embodiments described herein.

DETAILED DESCRIPTION

The following detailed description describes various features and functions of the disclosed systems, devices and methods with reference to the accompanying figures. In the figures, similar symbols identify similar components, unless context dictates otherwise. The illustrative system, device and method embodiments described herein are not meant to be limiting. It may be readily understood by those skilled in the art that certain aspects of the disclosed systems, devices and methods can be arranged and combined in a wide variety of different configurations, all of which are contemplated herein.

A light detection and ranging (LIDAR) device may transmit light pulses originating from a plurality of light sources and may receive reflected light pulses that are then detected by a plurality of detectors. Within examples described herein, a LIDAR device is provided that includes a transmit/receive lens that both collimates the light from the plurality of light sources and focuses the reflected light onto the plurality of detectors. By using a transmit/receive lens that performs both of these functions, instead of a transmit lens for collimating and a receive lens for focusing, advantages with respect to size, cost, and/or complexity can be provided.

The LIDAR device comprises a housing that is configured to rotate about an axis. In some examples, the axis is substantially vertical. The housing may have an interior space that includes various components such as a transmit block that includes the plurality of light sources, a receive block that includes the plurality of detectors, a shared space where emitted light traverses from the transmit block to the transmit/receive lens and reflected light traverses from the transmit/receive lens to the receive block, and the transmit/receive lens that collimates the emitted light and focuses the reflected light. By rotating the housing that includes the various components, in some examples, a three-dimensional map of a 360-degree field of view of an environment of the LIDAR device can be determined without frequent recalibration of the arrangement of the various components.

In some examples, the housing may include radio frequency (RF) and optical shielding between the transmit block and the receive block. For example, the housing can be formed from and/or coated by a metal, metallic ink, or metallic foam to provide the RF shielding. Metals used for shielding can include, for example, copper or nickel.

The plurality of light sources included in the transmit block can include, for example, laser diodes. In one example, the light sources emit light with wavelengths of approximately 905 nm. In some examples, a transmit path through which the transmit/receive lens receives the light emitted by the light sources may include a reflective element, such as a mirror or prism. By including the reflective element, the transmit path can be folded to provide a smaller size of the transmit block and, hence, a smaller housing of the LIDAR device. Additionally, the transmit path includes an exit aperture of the transmit block through which the emitted light enters the shared space and traverses to the transmit/receive lens.

In some examples, each light source of the plurality of light sources includes a respective lens, such as a cylindrical or acylindrical lens. The light source may emit an uncollimated light beam that diverges more in a first direction than in a second direction. In these examples, the light source's respective lens may pre-collimate the uncollimated light beam in the first direction to provide a partially collimated light beam, thereby reducing the divergence in the first direction. In some examples, the partially collimated light beam diverges less in the first direction than in the second direction. The transmit/receive lens receives the partially collimated light beams from the one or more light sources via an exit aperture of the transmit block and the transmit/receive lens collimates the partially collimated light beams to provide collimated light beams that are transmitted into the environment of the LIDAR device. In this example, the light emitted by the light sources may have a greater divergence in the second direction than in the first direction, and the exit aperture can accommodate vertical and horizontal extents of the beams of light from the light sources.

The housing mounts the transmit/receive lens through which light from the plurality of light sources can exit the housing, and reflected light can enter the housing to reach the receive block. The transmit/receive lens can have an optical power that is sufficient to collimate the light emitted by the plurality of light sources and to focus the reflected light onto the plurality of detectors in the receive block. In one example, the transmit/receive lens has a surface with an aspheric shape that is at the outside of the housing, a surface with a toroidal shape that is inside the housing, and a focal length of approximately 120 mm.

The plurality of detectors included in the receive block can include, for example, avalanche photodiodes in a sealed environment that is filled with an inert gas, such as nitrogen. The receive block can include an entrance aperture through which focused light from the transmit/receive lens traverses towards the detectors. In some examples, the entrance aperture can include a filtering window that passes light having wavelengths within the wavelength range emitted by the plurality of light sources and attenuates light having other wavelengths.

The collimated light transmitted from the LIDAR device into the environment may reflect from one or more objects in the environment to provide object-reflected light. The transmit/receive lens may collect the object-reflected light and focus the object-reflected light through a focusing path (“receive path”) onto the plurality of detectors. In some examples, the receive path may include a reflective surface that directs the focused light to the plurality of detectors. Additionally or alternatively, the reflective surface can fold the focused light towards the receive block and thus provide space savings for the shared space and the housing of the LIDAR device.

In some examples, the reflective surface may define a wall that includes the exit aperture between the transmit block and the shared space. In this case, the exit aperture of the transmit block corresponds to a transparent and/or non-reflective portion of the reflective surface. The transparent portion can be a hole or cut-away portion of the reflective surface. Alternatively, the reflective surface can be formed by forming a layer of reflective material on a transparent substrate (e.g., glass) and the transparent portion can be a portion of the substrate that is not coated with the reflective material. Thus, the shared space can be used for both the transmit path and the receive path. In some examples, the transmit path at least partially overlaps the receive path in the shared space.

The vertical and horizontal extents of the exit aperture are sufficient to accommodate the beam widths of the emitted light beams from the light sources. However, the non-reflective nature of the exit aperture prevents a portion of the collected and focused light in the receive path from reflecting, at the reflective surface, towards the detectors in the receive block. Thus, reducing the beam widths of the emitted light beams from the transmit blocks is desirable to minimize the size of the exit aperture and reduce the lost portion of the collected light. In some examples noted above, the reduction of the beam widths traversing through the exit aperture can be achieved by partially collimating the emitted light beams by including a respective lens, such as a cylindrical or acylindrical lens, adjacent to each light source.

Additionally or alternatively, to reduce the beam widths of the emitted light beams, in some examples, the transmit/receive lens can be configured to define a focal surface that has a substantial curvature in a vertical plane and/or a horizontal plane. For example, the transmit/receive lens can be configured to have the aspheric surface and the toroidal surface described above that provides the curved focal surface along the vertical plane and/or the horizontal plane. In this configuration, the light sources in the transmit block can be arranged along the transmit/receive lens' curved focal surface in the transmit block, and the detectors in the receive block can be arranged on the transmit/receive lens' curved focal surface in the receive block. Thus, the emitted light beams from the light sources arranged along the curved focal surface can converge into the exit aperture having a smaller size than an aperture for light beams that are substantially parallel and/or diverging.

To facilitate such curved arrangement of the light sources, in some examples, the light sources can be mounted on a curved edge of one or more vertically-oriented printed circuit boards (PCBs), such that the curved edge of the PCB substantially matches the curvature of the focal surface in the vertical plane of the PCB. In this example, the one or more PCBs can be mounted in the transmit block along a horizontal curvature that substantially matches the curvature of the focal surface in the horizontal plane of the one or more PCBs. For example, the transmit block can include four PCBs, with each PCB mounting sixteen light sources, so as to provide 64 light sources along the curved focal plane of the transmit/receive lens in the transmit block. In this example, the 64 light sources are arranged in a pattern substantially corresponding to the curved focal surface defined by the transmit/receive lens such that the emitted light beams converge towards the exit aperture of the transmit block.

For the receive block, in some examples, the plurality of detectors can be disposed on a flexible PCB that is mounted to the receive block to conform with the shape of the transmit/receive lens' focal surface. For example, the flexible PCB may be held between two clamping pieces that have surfaces corresponding to the shape of the focal surface. Additionally, in this example, each of the plurality of detectors can be arranged on the flexible PCB so as to receive focused light from the transmit/receive lens that corresponds to a respective light source of the plurality of light sources. In this example, the detectors can be arranged in a pattern substantially corresponding to the curved focal surface of the transmit/receive lens in the receive block. Thus, in this example, the transmit/receive lens can be configured to focus onto each detector of the plurality of detectors a respective portion of the collected light that comprises light from the detector's corresponding light source.

Some embodiments of the present disclosure therefore provide systems and methods for a LIDAR device that uses a shared transmit/receive lens. In some examples, such LIDAR device can include the shared lens configured to provide a curved focal plane for transmitting light sources and receiving detectors such that light from the light sources passes through a small exit aperture included in a reflective surface that reflects collected light towards the detectors.

<figref idref="DRAWINGS">FIG. 1</figref> is a block diagram of an example LIDAR device <b>100</b>. The LIDAR device <b>100</b> comprises a housing <b>110</b> that houses an arrangement of various components included in the LIDAR device <b>100</b> such as a transmit block <b>120</b>, a receive block <b>130</b>, a shared space <b>140</b>, and a lens <b>150</b>. The LIDAR device <b>100</b> includes the arrangement of the various components that provide emitted light beams <b>102</b> from the transmit block <b>120</b> that are collimated by the lens <b>150</b> and transmitted to an environment of the LIDAR device <b>100</b> as collimated light beams <b>104</b>, and collect reflected light <b>106</b> from one or more objects in the environment of the LIDAR device <b>100</b> by the lens <b>150</b> for focusing towards the receive block <b>130</b> as focused light <b>108</b>. The reflected light <b>106</b> comprises light from the collimated light beams <b>104</b> that was reflected by the one or more objects in the environment of the LIDAR device <b>100</b>. The emitted light beams <b>102</b> and the focused light <b>108</b> traverse in the shared space <b>140</b> also included in the housing <b>110</b>. In some examples, the emitted light beams <b>102</b> are propagating in a transmit path through the shared space <b>140</b> and the focused light <b>108</b> are propagating in a receive path through the shared space <b>140</b>. In some examples, the transmit path at least partially overlaps the receive path in the shared space <b>140</b>. The LIDAR device <b>100</b> can determine an aspect of the one or more objects (e.g., location, shape, etc.) in the environment of the LIDAR device <b>100</b> by processing the focused light <b>108</b> received by the receive block <b>130</b>. For example, the LIDAR device <b>100</b> can compare a time when pulses included in the emitted light beams <b>102</b> were emitted by the transmit block <b>120</b> with a time when corresponding pulses included in the focused light <b>108</b> were received by the receive block <b>130</b> and determine the distance between the one or more objects and the LIDAR device <b>100</b> based on the comparison.

The housing <b>110</b> included in the LIDAR device <b>100</b> can provide a platform for mounting the various components included in the LIDAR device <b>100</b>. The housing <b>110</b> can be formed from any material capable of supporting the various components of the LIDAR device <b>100</b> included in an interior space of the housing <b>110</b>. For example, the housing <b>110</b> may be formed from a structural material such as plastic or metal.

In some examples, the housing <b>110</b> can be configured for optical shielding to reduce ambient light and/or unintentional transmission of the emitted light beams <b>102</b> from the transmit block <b>120</b> to the receive block <b>130</b>. Optical shielding from ambient light of the environment of the LIDAR device <b>100</b> can be achieved by forming and/or coating the outer surface of the housing <b>110</b> with a material that blocks the ambient light from the environment. Additionally, inner surfaces of the housing <b>110</b> can include and/or be coated with the material described above to optically isolate the transmit block <b>120</b> from the receive block <b>130</b> to prevent the receive block <b>130</b> from receiving the emitted light beams <b>102</b> before the emitted light beams <b>102</b> reach the lens <b>150</b>.

In some examples, the housing <b>110</b> can be configured for electromagnetic shielding to reduce electromagnetic noise (e.g., Radio Frequency (RF) Noise, etc.) from ambient environment of the LIDAR device <b>110</b> and/or electromagnetic noise between the transmit block <b>120</b> and the receive block <b>130</b>. Electromagnetic shielding can improve quality of the emitted light beams <b>102</b> emitted by the transmit block <b>120</b> and reduce noise in signals received and/or provided by the receive block <b>130</b>. Electromagnetic shielding can be achieved by forming and/or coating the housing <b>110</b> with a material that absorbs electromagnetic radiation such as a metal, metallic ink, metallic foam, carbon foam, or any other material configured to absorb electromagnetic radiation. Metals that can be used for the electromagnetic shielding can include for example, copper or nickel.

In some examples, the housing <b>110</b> can be configured to have a substantially cylindrical shape and to rotate about an axis of the LIDAR device <b>100</b>. For example, the housing <b>110</b> can have the substantially cylindrical shape with a diameter of approximately <b>10</b> centimeters. In some examples, the axis is substantially vertical. By rotating the housing <b>110</b> that includes the various components, in some examples, a three-dimensional map of a 360 degree view of the environment of the LIDAR device <b>100</b> can be determined without frequent recalibration of the arrangement of the various components of the LIDAR device <b>100</b>. Additionally or alternatively, the LIDAR device <b>100</b> can be configured to tilt the axis of rotation of the housing <b>110</b> to control the field of view of the LIDAR device <b>100</b>.

Although not illustrated in <figref idref="DRAWINGS">FIG. 1</figref>, the LIDAR device <b>100</b> can optionally include a mounting structure for the housing <b>110</b>. The mounting structure can include a motor or other means for rotating the housing <b>110</b> about the axis of the LIDAR device <b>100</b>. Alternatively, the mounting structure can be included in a device and/or system other than the LIDAR device <b>100</b>.

In some examples, the various components of the LIDAR device <b>100</b> such as the transmit block <b>120</b>, receive block <b>130</b>, and the lens <b>150</b> can be removably mounted to the housing <b>110</b> in predetermined positions to reduce burden of calibrating the arrangement of each component and/or subcomponents included in each component. Thus, the housing <b>110</b> provides the platform for the various components of the LIDAR device <b>100</b> for ease of assembly, maintenance, calibration, and manufacture of the LIDAR device <b>100</b>.

The transmit block <b>120</b> includes a plurality of light sources <b>122</b> that can be configured to emit the plurality of emitted light beams <b>102</b> via an exit aperture <b>124</b>. In some examples, each of the plurality of emitted light beams <b>102</b> corresponds to one of the plurality of light sources <b>122</b>. The transmit block <b>120</b> can optionally include a mirror <b>126</b> along the transmit path of the emitted light beams <b>102</b> between the light sources <b>122</b> and the exit aperture <b>124</b>.

The light sources <b>122</b> can include laser diodes, light emitting diodes (LED), vertical cavity surface emitting lasers (VCSEL), organic light emitting diodes (OLED), polymer light emitting diodes (PLED), light emitting polymers (LEP), liquid crystal displays (LCD), microelectromechanical systems (MEMS), or any other device configured to selectively transmit, reflect, and/or emit light to provide the plurality of emitted light beams <b>102</b>. In some examples, the light sources <b>122</b> can be configured to emit the emitted light beams <b>102</b> in a wavelength range that can be detected by detectors <b>132</b> included in the receive block <b>130</b>. The wavelength range could, for example, be in the ultraviolet, visible, and/or infrared portions of the electromagnetic spectrum. In some examples, the wavelength range can be a narrow wavelength range, such as provided by lasers. In one example, the wavelength range includes wavelengths that are approximately 905 nm. Additionally, the light sources <b>122</b> can be configured to emit the emitted light beams <b>102</b> in the form of pulses. In some examples, the plurality of light sources <b>122</b> can be disposed on one or more substrates (e.g., printed circuit boards (PCB), flexible PCBs, etc.) and arranged to emit the plurality of light beams <b>102</b> towards the exit aperture <b>124</b>.

In some examples, the plurality of light sources <b>122</b> can be configured to emit uncollimated light beams included in the emitted light beams <b>102</b>. For example, the emitted light beams <b>102</b> can diverge in one or more directions along the transmit path due to the uncollimated light beams emitted by the plurality of light sources <b>122</b>. In some examples, vertical and horizontal extents of the emitted light beams <b>102</b> at any position along the transmit path can be based on an extent of the divergence of the uncollimated light beams emitted by the plurality of light sources <b>122</b>.

The exit aperture <b>124</b> arranged along the transmit path of the emitted light beams <b>102</b> can be configured to accommodate the vertical and horizontal extents of the plurality of light beams <b>102</b> emitted by the plurality of light sources <b>122</b> at the exit aperture <b>124</b>. It is noted that the block diagram shown in <figref idref="DRAWINGS">FIG. 1</figref> is described in connection with functional modules for convenience in description. However, the functional modules in the block diagram of <figref idref="DRAWINGS">FIG. 1</figref> can be physically implemented in other locations. For example, although illustrated that the exit aperture <b>124</b> is included in the transmit block <b>120</b>, the exit aperture <b>124</b> can be physically included in both the transmit block <b>120</b> and the shared space <b>140</b>. For example, the transmit block <b>120</b> and the shared space <b>140</b> can be separated by a wall that includes the exit aperture <b>124</b>. In this case, the exit aperture <b>124</b> can correspond to a transparent portion of the wall. In one example, the transparent portion can be a hole or cut-away portion of the wall. In another example, the wall can be formed from a transparent substrate (e.g., glass) coated with a non-transparent material, and the exit aperture <b>124</b> can be a portion of the substrate that is not coated with the non-transparent material.

In some examples of the LIDAR device <b>100</b>, it may be desirable to minimize size of the exit aperture <b>124</b> while accommodating the vertical and horizontal extents of the plurality of light beams <b>102</b>. For example, minimizing the size of the exit aperture <b>124</b> can improve the optical shielding of the light sources <b>122</b> described above in the functions of the housing <b>110</b>. Additionally or alternatively, the wall separating the transmit block <b>120</b> and the shared space <b>140</b> can be arranged along the receive path of the focused light <b>108</b>, and thus, the exit aperture <b>124</b> can be minimized to allow a larger portion of the focused light <b>108</b> to reach the wall. For example, the wall can be coated with a reflective material (e.g., reflective surface <b>142</b> in shared space <b>140</b>) and the receive path can include reflecting the focused light <b>108</b> by the reflective material towards the receive block <b>130</b>. In this case, minimizing the size of the exit aperture <b>124</b> can allow a larger portion of the focused light <b>108</b> to reflect off the reflective material that the wall is coated with.

To minimize the size of the exit aperture <b>124</b>, in some examples, the divergence of the emitted light beams <b>102</b> can be reduced by partially collimating the uncollimated light beams emitted by the light sources <b>122</b> to minimize the vertical and horizontal extents of the emitted light beams <b>102</b> and thus minimize the size of the exit aperture <b>124</b>. For example, each light source of the plurality of light sources <b>122</b> can include a cylindrical lens arranged adjacent to the light source. The light source may emit a corresponding uncollimated light beam that diverges more in a first direction than in a second direction. The cylindrical lens may pre-collimate the uncollimated light beam in the first direction to provide a partially collimated light beam, thereby reducing the divergence in the first direction. In some examples, the partially collimated light beam diverges less in the first direction than in the second direction. Similarly, uncollimated light beams from other light sources of the plurality of light sources <b>122</b> can have a reduced beam width in the first direction and thus the emitted light beams <b>102</b> can have a smaller divergence due to the partially collimated light beams. In this example, at least one of the vertical and horizontal extents of the exit aperture <b>124</b> can be reduced due to partially collimating the light beams <b>102</b>.

Additionally or alternatively, to minimize the size of the exit aperture <b>124</b>, in some examples, the light sources <b>122</b> can be arranged along a substantially curved surface defined by the transmit block <b>120</b>. The curved surface can be configured such that the emitted light beams <b>102</b> converge towards the exit aperture <b>124</b>, and thus the vertical and horizontal extents of the emitted light beams <b>102</b> at the exit aperture <b>124</b> can be reduced due to the arrangement of the light sources <b>122</b> along the curved surface of the transmit block <b>120</b>. In some examples, the curved surface of the transmit block <b>120</b> can include a curvature along the first direction of divergence of the emitted light beams <b>102</b> and a curvature along the second direction of divergence of the emitted light beams <b>102</b>, such that the plurality of light beams <b>102</b> converge towards a central area in front of the plurality of light sources <b>122</b> along the transmit path.

To facilitate such curved arrangement of the light sources <b>122</b>, in some examples, the light sources <b>122</b> can be disposed on a flexible substrate (e.g., flexible PCB) having a curvature along one or more directions. For example, the curved flexible substrate can be curved along the first direction of divergence of the emitted light beams <b>102</b> and the second direction of divergence of the emitted light beams <b>102</b>. Additionally or alternatively, to facilitate such curved arrangement of the light sources <b>122</b>, in some examples, the light sources <b>122</b> can be disposed on a curved edge of one or more vertically-oriented printed circuit boards (PCBs), such that the curved edge of the PCB substantially matches the curvature of the first direction (e.g., the vertical plane of the PCB). In this example, the one or more PCBs can be mounted in the transmit block <b>120</b> along a horizontal curvature that substantially matches the curvature of the second direction (e.g., the horizontal plane of the one or more PCBs). For example, the transmit block <b>120</b> can include four PCBs, with each PCB mounting sixteen light sources, so as to provide 64 light sources along the curved surface of the transmit block <b>120</b>. In this example, the 64 light sources are arranged in a pattern such that the emitted light beams <b>102</b> converge towards the exit aperture <b>124</b> of the transmit block <b>120</b>.

The transmit block <b>120</b> can optionally include the mirror <b>126</b> along the transmit path of the emitted light beams <b>102</b> between the light sources <b>122</b> and the exit aperture <b>124</b>. By including the mirror <b>126</b> in the transmit block <b>120</b>, the transmit path of the emitted light beams <b>102</b> can be folded to provide a smaller size of the transmit block <b>120</b> and the housing <b>110</b> of the LIDAR device <b>100</b> than a size of another transmit block where the transmit path that is not folded.

The receive block <b>130</b> includes a plurality of detectors <b>132</b> that can be configured to receive the focused light <b>108</b> via an entrance aperture <b>134</b>. In some examples, each of the plurality of detectors <b>132</b> is configured and arranged to receive a portion of the focused light <b>108</b> corresponding to a light beam emitted by a corresponding light source of the plurality of light sources <b>122</b> and reflected of the one or more objects in the environment of the LIDAR device <b>100</b>. The receive block <b>130</b> can optionally include the detectors <b>132</b> in a sealed environment having an inert gas <b>136</b>.

The detectors <b>132</b> may comprise photodiodes, avalanche photodiodes, phototransistors, cameras, active pixel sensors (APS), charge coupled devices (CCD), cryogenic detectors, or any other sensor of light configured to receive focused light <b>108</b> having wavelengths in the wavelength range of the emitted light beams <b>102</b>.

To facilitate receiving, by each of the detectors <b>132</b>, the portion of the focused light <b>108</b> from the corresponding light source of the plurality of light sources <b>122</b>, the detectors <b>132</b> can be disposed on one or more substrates and arranged accordingly. For example, the light sources <b>122</b> can be arranged along a curved surface of the transmit block <b>120</b>, and the detectors <b>132</b> can also be arranged along a curved surface of the receive block <b>130</b>. The curved surface of the receive block <b>130</b> can similarly be curved along one or more axes of the curved surface of the receive block <b>130</b>. Thus, each of the detectors <b>132</b> are configured to receive light that was originally emitted by a corresponding light source of the plurality of light sources <b>122</b>.

To provide the curved surface of the receive block <b>130</b>, the detectors <b>132</b> can be disposed on the one or more substrates similarly to the light sources <b>122</b> disposed in the transmit block <b>120</b>. For example, the detectors <b>132</b> can be disposed on a flexible substrate (e.g., flexible PCB) and arranged along the curved surface of the flexible substrate to each receive focused light originating from a corresponding light source of the light sources <b>122</b>. In this example, the flexible substrate may be held between two clamping pieces that have surfaces corresponding to the shape of the curved surface of the receive block <b>130</b>. Thus, in this example, assembly of the receive block <b>130</b> can be simplified by sliding the flexible substrate onto the receive block <b>130</b> and using the two clamping pieces to hold it at the correct curvature.

The focused light <b>108</b> traversing along the receive path can be received by the detectors <b>132</b> via the entrance aperture <b>134</b>. In some examples, the entrance aperture <b>134</b> can include a filtering window that passes light having wavelengths within the wavelength range emitted by the plurality of light sources <b>122</b> and attenuates light having other wavelengths. In this example, the detectors <b>132</b> receive the focused light <b>108</b> substantially comprising light having the wavelengths within the wavelength range.

In some examples, the plurality of detectors <b>132</b> included in the receive block <b>130</b> can include, for example, avalanche photodiodes in a sealed environment that is filled with the inert gas <b>136</b>. The inert gas <b>136</b> may comprise, for example, nitrogen.

The shared space <b>140</b> includes the transmit path for the emitted light beams <b>102</b> from the transmit block <b>120</b> to the lens <b>150</b>, and includes the receive path for the focused light <b>108</b> from the lens <b>150</b> to the receive block <b>130</b>. In some examples, the transmit path at least partially overlaps with the receive path in the shared space <b>140</b>. By including the transmit path and the receive path in the shared space <b>140</b>, advantages with respect to size, cost, and/or complexity of assembly, manufacture, and/or maintenance of the LIDAR device <b>100</b> can be provided.

In some examples, the shared space <b>140</b> can include a reflective surface <b>142</b>. The reflective surface <b>142</b> can be arranged along the receive path and configured to reflect the focused light <b>108</b> towards the entrance aperture <b>134</b> and onto the detectors <b>132</b>. The reflective surface <b>142</b> may comprise a prism, mirror or any other optical element configured to reflect the focused light <b>108</b> towards the entrance aperture <b>134</b> in the receive block <b>130</b>. In some examples where a wall separates the shared space <b>140</b> from the transmit block <b>120</b>. In these examples, the wall may comprise a transparent substrate (e.g., glass) and the reflective surface <b>142</b> may comprise a reflective coating on the wall with an uncoated portion for the exit aperture <b>124</b>.

In embodiments including the reflective surface <b>142</b>, the reflective surface <b>142</b> can reduce size of the shared space <b>140</b> by folding the receive path similarly to the mirror <b>126</b> in the transmit block <b>120</b>. Additionally or alternatively, in some examples, the reflective surface <b>142</b> can direct the focused light <b>103</b> to the receive block <b>130</b> further providing flexibility to the placement of the receive block <b>130</b> in the housing <b>110</b>. For example, varying the tilt of the reflective surface <b>142</b> can cause the focused light <b>108</b> to be reflected to various portions of the interior space of the housing <b>110</b>, and thus the receive block <b>130</b> can be placed in a corresponding position in the housing <b>110</b>. Additionally or alternatively, in this example, the LIDAR device <b>100</b> can be calibrated by varying the tilt of the reflective surface <b>142</b>.

The lens <b>150</b> mounted to the housing <b>110</b> can have an optical power to both collimate the emitted light beams <b>102</b> from the light sources <b>122</b> in the transmit block <b>120</b>, and focus the reflected light <b>106</b> from the one or more objects in the environment of the LIDAR device <b>100</b> onto the detectors <b>132</b> in the receive block <b>130</b>. In one example, the lens <b>150</b> has a focal length of approximately 120 mm. By using the same lens <b>150</b> to perform both of these functions, instead of a transmit lens for collimating and a receive lens for focusing, advantages with respect to size, cost, and/or complexity can be provided. In some examples, collimating the emitted light beams <b>102</b> to provide the collimated light beams <b>104</b> allows determining the distance travelled by the collimated light beams <b>104</b> to the one or more objects in the environment of the LIDAR device <b>100</b>.

In an example scenario, the emitted light beams <b>102</b> from the light sources <b>122</b> traversing along the transmit path can be collimated by the lens <b>150</b> to provide the collimated light beams <b>104</b> to the environment of the LIDAR device <b>100</b>. The collimated light beams <b>104</b> may then reflect off the one or more objects in the environment of the LIDAR device <b>100</b> and return to the lens <b>150</b> as the reflected light <b>106</b>. The lens <b>150</b> may then collect and focus the reflected light <b>106</b> as the focused light <b>108</b> onto the detectors <b>132</b> included in the receive block <b>130</b>. In some examples, aspects of the one or more objects in the environment of the LIDAR device <b>100</b> can be determined by comparing the emitted light beams <b>102</b> with the focused light beams <b>108</b>. The aspects can include, for example, distance, shape, color, and/or material of the one or more objects. Additionally, in some examples, rotating the housing <b>110</b>, a three dimensional map of the surroundings of the LIDAR device <b>100</b> can be determined.

In some examples where the plurality of light sources <b>122</b> are arranged along the curved surface of the transmit block <b>120</b>, the lens <b>150</b> can be configured to have a focal surface corresponding to the curved surface of the transmit block <b>120</b>. For example, the lens <b>150</b> can include an aspheric surface outside the housing <b>110</b> and a toroidal surface inside the housing <b>110</b> facing the shared space <b>140</b>. In this example, the shape of the lens <b>150</b> allows the lens <b>150</b> to both collimate the emitted light beams <b>102</b> and focus the reflected light <b>106</b>. Additionally, in this example, the shape of the lens <b>150</b> allows the lens <b>150</b> to have the focal surface corresponding to the curved surface of the transmit block <b>120</b>. In some examples, the focal surface provided by the lens <b>150</b> substantially matches the curved shape of the transmit block <b>120</b>. Additionally, in some examples, the detectors <b>132</b> can be arranged similarly in the curved shape of the receive block <b>130</b> to receive the focused light <b>108</b> along the curved focal surface provided by the lens <b>150</b>. Thus, in some examples, the curved surface of the receive block <b>130</b> may also substantially match the curved focal surface provided by the lens <b>150</b>.

<figref idref="DRAWINGS">FIG. 2</figref> is a cross-section view of an example LIDAR device <b>200</b>. In this example, the LIDAR device <b>200</b> includes a housing <b>210</b> that houses a transmit block <b>220</b>, a receive block <b>230</b>, a shared space <b>240</b>, and a lens <b>250</b>. For purposes of illustration, <figref idref="DRAWINGS">FIG. 2</figref> shows an x-y-z axis, in which the z-axis is in a substantially vertical direction and the x-axis and y-axis define a substantially horizontal plane.

The structure, function, and operation of various components included in the LIDAR device <b>200</b> are similar to corresponding components included in the LIDAR device <b>100</b> described in <figref idref="DRAWINGS">FIG. 1</figref>. For example, the housing <b>210</b>, the transmit block <b>220</b>, the receive block <b>230</b>, the shared space <b>240</b>, and the lens <b>250</b> are similar, respectively, to the housing <b>110</b>, the transmit block <b>120</b>, the receive block <b>130</b>, and the shared space <b>140</b> described in <figref idref="DRAWINGS">FIG. 1</figref>.

The transmit block <b>220</b> includes a plurality of light sources <b>222</b>a-c arranged along a curved focal surface <b>228</b> defined by the lens <b>250</b>. The plurality of light sources <b>222</b>a-c can be configured to emit, respectively, the plurality of light beams <b>202</b>a-c having wavelengths within a wavelength range. For example, the plurality of light sources <b>222</b>a-c may comprise laser diodes that emit the plurality of light beams <b>202</b>a-c having the wavelengths within the wavelength range. The plurality of light beams <b>202</b>a-c are reflected by mirror <b>224</b> through an exit aperture <b>226</b> into the shared space <b>240</b> and towards the lens <b>250</b>. The structure, function, and operation of the plurality of light sources <b>222</b>a-c, the mirror <b>224</b>, and the exit aperture <b>226</b> can be similar, respectively, to the plurality of light sources <b>122</b>, the mirror <b>124</b>, and the exit aperture <b>226</b> discussed in the description of the LIDAR device <b>100</b> of <figref idref="DRAWINGS">FIG. 1</figref>.

Although <figref idref="DRAWINGS">FIG. 2</figref> shows that the curved focal surface <b>228</b> is curved in the x-y plane (horizontal plane), additionally or alternatively, the plurality of light sources <b>222</b>a-c may be arranged along a focal surface that is curved in a vertical plane. For example, the curved focal surface <b>228</b> can have a curvature in a vertical plane, and the plurality of light sources <b>222</b>a-c can include additional light sources arranged vertically along the curved focal surface <b>228</b> and configured to emit light beams directed at the mirror <b>224</b> and reflected through the exit aperture <b>226</b>.

Due to the arrangement of the plurality of light sources <b>222</b>a-c along the curved focal surface <b>228</b>, the plurality of light beams <b>202</b>a-c, in some examples, may converge towards the exit aperture <b>226</b>. Thus, in these examples, the exit aperture <b>226</b> may be minimally sized while being capable of accommodating vertical and horizontal extents of the plurality of light beams <b>202</b>a-c. Additionally, in some examples, the curved focal surface <b>228</b> can be defined by the lens <b>250</b>. For example, the curved focal surface <b>228</b> may correspond to a focal surface of the lens <b>250</b> due to shape and composition of the lens <b>250</b>. In this example, the plurality of light sources <b>222</b>a-c can be arranged along the focal surface defined by the lens <b>250</b> at the transmit block.

The plurality of light beams <b>202</b>a-c propagate in a transmit path that extends through the transmit block <b>220</b>, the exit aperture <b>226</b>, and the shared space <b>240</b> towards the lens <b>250</b>. The lens <b>250</b> collimates the plurality of light beams <b>202</b>a-c to provide collimated light beams <b>204</b>a-c into an environment of the LIDAR device <b>200</b>. The collimated light beams <b>204</b>a-c correspond, respectively, to the plurality of light beams <b>202</b>a-c. In some examples, the collimated light beams <b>204</b>a-c reflect off one or more objects in the environment of the LIDAR device <b>200</b> as reflected light <b>206</b>. The reflected light <b>206</b> may be focused by the lens <b>250</b> into the shared space <b>240</b> as focused light <b>208</b> traveling along a receive path that extends through the shared space <b>240</b> onto the receive block <b>230</b>. For example, the focused light <b>208</b> may be reflected by the reflective surface <b>242</b> as focused light <b>208</b>a-c propagating towards the receive block <b>230</b>.

The lens <b>250</b> may be capable of both collimating the plurality of light beams <b>202</b>a-c and focusing the reflected light <b>206</b> along the receive path <b>208</b> towards the receive block <b>230</b> due to shape and composition of the lens <b>250</b>. For example, the lens <b>250</b> can have an aspheric surface <b>252</b> facing outside of the housing <b>210</b> and a toroidal surface <b>254</b> facing the shared space <b>240</b>. By using the same lens <b>250</b> to perform both of these functions, instead of a transmit lens for collimating and a receive lens for focusing, advantages with respect to size, cost, and/or complexity can be provided.

The exit aperture <b>226</b> is included in a wall <b>244</b> that separates the transmit block <b>220</b> from the shared space <b>240</b>. In some examples, the wall <b>244</b> can be formed from a transparent material (e.g., glass) that is coated with a reflective material <b>242</b>. In this example, the exit aperture <b>226</b> may correspond to the portion of the wall <b>244</b> that is not coated by the reflective material <b>242</b>. Additionally or alternatively, the exit aperture <b>226</b> may comprise a hole or cut-away in the wall <b>244</b>.

The focused light <b>208</b> is reflected by the reflective surface <b>242</b> and directed towards an entrance aperture <b>234</b> of the receive block <b>230</b>. In some examples, the entrance aperture <b>234</b> may comprise a filtering window configured to allow wavelengths in the wavelength range of the plurality of light beams <b>202</b>a-c emitted by the plurality of light sources <b>222</b>a-c and attenuate other wavelengths. The focused light <b>208</b>a-c reflected by the reflective surface <b>242</b> from the focused light <b>208</b> propagates, respectively, onto a plurality of detectors <b>232</b>a-c. The structure, function, and operation of the entrance aperture <b>234</b> and the plurality of detectors <b>232</b>a-c is similar, respectively, to the entrance aperture <b>134</b> and the plurality of detectors <b>132</b> included in the LIDAR device <b>100</b> described in <figref idref="DRAWINGS">FIG. 1</figref>.

The plurality of detectors <b>232</b>a-c can be arranged along a curved focal surface <b>238</b> of the receive block <b>230</b>. Although <figref idref="DRAWINGS">FIG. 2</figref> shows that the curved focal surface <b>238</b> is curved along the x-y plane (horizontal plane), additionally or alternatively, the curved focal surface <b>238</b> can be curved in a vertical plane. The curvature of the focal surface <b>238</b> is also defined by the lens <b>250</b>. For example, the curved focal surface <b>238</b> may correspond to a focal surface of the light projected by the lens <b>250</b> along the receive path at the receive block <b>230</b>.

Each of the focused light <b>208</b>a-c corresponds, respectively, to the emitted light beams <b>202</b>a-c and is directed onto, respectively, the plurality of detectors <b>232</b>a-c. For example, the detector <b>232</b>a is configured and arranged to received focused light <b>208</b>a that corresponds to collimated light beam <b>204</b>a reflected of the one or more objects in the environment of the LIDAR device <b>200</b>. In this example, the collimated light beam <b>204</b>a corresponds to the light beam <b>202</b>a emitted by the light source <b>222</b>a. Thus, the detector <b>232</b>a receives light that was emitted by the light source <b>222</b>a, the detector <b>232</b>b receives light that was emitted by the light source <b>222</b>b, and the detector <b>232</b>c receives light that was emitted by the light source <b>222</b>c.

By comparing the received light <b>208</b>a-c with the emitted light beams <b>202</b>a-c, at least one aspect of the one or more object in the environment of the LIDAR device <b>200</b> may be determined. For example, by comparing a time when the plurality of light beams <b>202</b>a-c were emitted by the plurality of light sources <b>222</b>a-c and a time when the plurality of detectors <b>232</b>a-c received the focused light <b>208</b>a-c, a distance between the LIDAR device <b>200</b> and the one or more object in the environment of the LIDAR device <b>200</b> may be determined. In some examples, other aspects such as shape, color, material, etc. may also be determined.

In some examples, the LIDAR device <b>200</b> may be rotated about an axis to determine a three-dimensional map of the surroundings of the LIDAR device <b>200</b>. For example, the LIDAR device <b>200</b> may be rotated about a substantially vertical axis as illustrated by arrow <b>290</b>. Although illustrated that the LIDAR device <b>200</b> is rotated counter clock-wise about the axis as illustrated by the arrow <b>290</b>, additionally or alternatively, the LIDAR device <b>200</b> may be rotated in the clockwise direction. In some examples, the LIDAR device <b>200</b> may be rotated 360 degrees about the axis. In other examples, the LIDAR device <b>200</b> may be rotated back and forth along a portion of the 360 degree view of the LIDAR device <b>200</b>. For example, the LIDAR device <b>200</b> may be mounted on a platform that wobbles back and forth about the axis without making a complete rotation.

<figref idref="DRAWINGS">FIG. 3A</figref> is a perspective view of an example LIDAR device <b>300</b> fitted with various components, in accordance with at least some embodiments described herein. <figref idref="DRAWINGS">FIG. 3B</figref> is a perspective view of the example LIDAR device <b>300</b> shown in <figref idref="DRAWINGS">FIG. 3A</figref> with the various components removed to illustrate interior space of the housing <b>310</b>. The structure, function, and operation of the LIDAR device <b>300</b> is similar to the LIDAR devices <b>100</b> and <b>200</b> described, respectively, in <figref idref="DRAWINGS">FIGS. 1 and 2</figref>. For example, the LIDAR device <b>300</b> includes a housing <b>310</b> that houses a transmit block <b>320</b>, a receive block <b>330</b>, and a lens <b>350</b> that are similar, respectively, to the housing <b>110</b>, the transmit block <b>120</b>, the receive block <b>130</b>, and the lens <b>150</b> described in <figref idref="DRAWINGS">FIG. 1</figref>. Additionally, collimated light beams <b>304</b> propagate from the lens <b>350</b> toward an environment of the LIDAR device <b>300</b> and reflect of one or more objects in the environment as reflected light <b>306</b>, similarly to the collimated light beams <b>104</b> and reflected light <b>106</b> described in <figref idref="DRAWINGS">FIG. 1</figref>.

The LIDAR device <b>300</b> can be mounted on a mounting structure <b>360</b> and rotated about an axis to provide a 360 degree view of the environment surrounding the LIDAR device <b>300</b>. In some examples, the mounting structure <b>360</b> may comprise a movable platform that may tilt in one or more directions to change the axis of rotation of the LIDAR device <b>300</b>.

As illustrated in <figref idref="DRAWINGS">FIG. 3B</figref>, the various components of the LIDAR device <b>300</b> can be removably mounted to the housing <b>310</b>. For example, the transmit block <b>320</b> may comprise one or more printed circuit boards (PCBs) that are fitted in the portion of the housing <b>310</b> where the transmit block <b>320</b> can be mounted. Additionally, the receive block <b>330</b> may comprise a plurality of detectors <b>332</b> mounted to a flexible substrate and can be removably mounted to the housing <b>310</b> as a block that includes the plurality of detectors. Similarly, the lens <b>350</b> can be mounted to another side of the housing <b>310</b>.

A plurality of light beams <b>302</b> can be transmitted by the transmit block <b>320</b> into the shared space <b>340</b> and towards the lens <b>350</b> to be collimated into the collimated light beams <b>304</b>. Similarly, the received light <b>306</b> can be focused by the lens <b>350</b> and directed through the shared space <b>340</b> onto the receive block <b>330</b>.

<figref idref="DRAWINGS">FIG. 4</figref> illustrates an example transmit block <b>420</b>, in accordance with at least some embodiments described herein. Transmit block <b>420</b> can correspond to the transmit blocks <b>120</b>, <b>220</b>, and <b>320</b> described in <figref idref="DRAWINGS">FIGS. 1-3</figref>. For example, the transmit block <b>420</b> includes a plurality of light sources <b>422</b>a-c similar to the plurality of light sources <b>222</b>a-c included in the transmit block <b>220</b> of <figref idref="DRAWINGS">FIG. 2</figref>. Additionally, the light sources <b>422</b>a-c are arranged along a focal surface <b>428</b>, which is curved in a vertical plane. The light sources <b>422</b>a-c are configured to emit a plurality of light beams <b>402</b>a-c that converge and propagate through an exit aperture <b>426</b> in a wall <b>444</b>.

Although the plurality of light sources <b>422</b>a-c can be arranged along a focal surface <b>428</b> that is curved in a vertical plane, additionally or alternatively, the plurality of light sources <b>422</b>a-c can be arranged along a focal surface that is curved in a horizontal plane or a focal surface that is curved both vertically and horizontally. For example, the plurality of light sources <b>422</b>a-c can be arranged in a curved three dimensional grid pattern. For example, the transmit block <b>420</b> may comprise a plurality of printed circuit board (PCB) vertically mounted such that a column of light sources such as the plurality of light sources <b>422</b>a-c are along the vertical axis of each PCB and each of the plurality of PCBs can be arranged adjacent to other vertically mounted PCBs along a horizontally curved plane to provide the three dimensional grid pattern.

As shown in <figref idref="DRAWINGS">FIG. 4</figref>, the light beams <b>402</b>a-c converge towards the exit aperture <b>426</b> which allows the size of the exit aperture <b>426</b> to be minimized while accommodating vertical and horizontal extents of the light beams <b>402</b>a-c similarly to the exit aperture <b>226</b> described in <figref idref="DRAWINGS">FIG. 2</figref>.

As noted above in the description of <figref idref="DRAWINGS">FIG. 1</figref>, the light from light sources <b>122</b> could be partially collimated to fit through the exit aperture <b>124</b>. <figref idref="DRAWINGS">FIGS. 5A, 5B, and 5C</figref> illustrate an example of how such partial collimation could be achieved. In this example, a light source <b>500</b> is made up of a laser diode <b>502</b> and a cylindrical lens <b>504</b>. As shown in <figref idref="DRAWINGS">FIG. 5A</figref>, laser diode <b>502</b> has an aperture <b>506</b> with a shorter dimension corresponding to a fast axis <b>508</b> and a longer dimension corresponding to a slow axis <b>510</b>. <figref idref="DRAWINGS">FIGS. 5B and 5C</figref> show an uncollimated laser beam <b>512</b> being emitted from laser diode <b>502</b>. Laser beam <b>512</b> diverges in two directions, one direction defined by fast axis <b>508</b> and another, generally orthogonal direction defined by slow axis <b>510</b>. <figref idref="DRAWINGS">FIG. 5B</figref> shows the divergence of laser beam <b>512</b> along fast axis <b>508</b>, whereas <figref idref="DRAWINGS">FIG. 5C</figref> shows the divergence of laser beam <b>512</b> along slow axis <b>510</b>. Laser beam <b>512</b> diverges more quickly along fast axis <b>508</b> than along slow axis <b>510</b>.

In one specific example, laser diode <b>502</b> is an Osram SPL DL90_3 nanostack pulsed laser diode that emits pulses of light with a range of wavelengths from about 896 nm to about 910 nm (a nominal wavelength of 905 nm). In this specific example, the aperture has a shorter dimension of about 10 microns, corresponding to its fast axis, and a longer dimension of about 200 microns, corresponding to its slow axis. The divergence of the laser beam in this specific example is about 25 degrees along the fast axis and about 11 degrees along the slow axis. It is to be understood that this specific example is illustrative only. Laser diode <b>502</b> could have a different configuration, different aperture sizes, different beam divergences, and/or emit different wavelengths.

As shown in <figref idref="DRAWINGS">FIGS. 5B and 5C</figref>, cylindrical lens <b>504</b> may be positioned in front of aperture <b>506</b> with its cylinder axis <b>514</b> generally parallel to slow axis <b>510</b> and perpendicular to fast axis <b>508</b>. In this arrangement, cylindrical lens <b>504</b> can pre-collimate laser beam <b>512</b> along fast axis <b>508</b>, resulting in partially collimated laser beam <b>516</b>. In some examples, this pre-collimation may reduce the divergence along fast axis <b>508</b> to about one degree or less. Nonetheless, laser beam <b>516</b> is only partially collimated because the divergence along slow axis <b>510</b> may be largely unchanged by cylindrical lens <b>504</b>. Thus, whereas uncollimated laser beam <b>512</b> emitted by laser diode has a higher divergence along fast axis <b>508</b> than along slow axis <b>510</b>, partially collimated laser beam <b>516</b> provided by cylindrical lens <b>504</b> may have a higher divergence along slow axis <b>510</b> than along fast axis <b>508</b>. Further, the divergences along slow axis <b>510</b> in uncollimated laser beam <b>512</b> and in partially collimated laser beam <b>516</b> may be substantially equal.

In one example, cylindrical lens <b>504</b> is a microrod lens with a diameter of about 600 microns that is placed about 250 microns in front of aperture <b>506</b>. The material of the microrod lens could be, for example, fused silica or a borosilicate crown glass, such as Schott BK7. Alternatively, the microrod lens could be a molded plastic cylinder or acylinder. Cylindrical lens <b>504</b> could also be used to provide magnification along fast axis <b>508</b>. For example, if the dimensions of aperture <b>506</b> are 10 microns by 200 microns, as previously described, and cylindrical lens <b>504</b> is a microrod lens as described above, then cylindrical lens <b>504</b> may magnify the shorter dimension (corresponding to fast axis <b>508</b>) by about 20 times. This magnification effectively stretches out the shorter dimension of aperture <b>506</b> to about the same as the longer dimension. As a result, when light from laser beam <b>516</b> is focused, for example, focused onto a detector, the focused spot could have a substantially square shape instead of the rectangular slit shape of aperture <b>506</b>.

<figref idref="DRAWINGS">FIG. 6A</figref> illustrates an example receive block <b>630</b>, in accordance with at least some embodiments described herein. <figref idref="DRAWINGS">FIG. 6B</figref> illustrates a side view of three detectors <b>632</b>a-c included in the receive block <b>630</b> of <figref idref="DRAWINGS">FIG. 6A</figref>. Receive block <b>630</b> can correspond to the receive blocks <b>130</b>, <b>230</b>, and <b>330</b> described in <figref idref="DRAWINGS">FIGS. 1-3</figref>. For example, the receive block <b>630</b> includes a plurality of detectors <b>632</b>a-c arranged along a curved surface <b>638</b> defined by a lens <b>650</b> similarly to the receive block <b>230</b>, the detectors <b>232</b> and the curved plane <b>238</b> described in <figref idref="DRAWINGS">FIG. 2</figref>. Focused light <b>608</b>a-c from lens <b>650</b> propagates along a receive path that includes a reflective surface <b>642</b> onto the detectors <b>632</b>a-c similar, respectively, to the focused light <b>208</b>a-c, the lens <b>250</b>, the reflective surface <b>242</b>, and the detectors <b>232</b>a-c described in <figref idref="DRAWINGS">FIG. 2</figref>.

The receive block <b>630</b> comprises a flexible substrate <b>680</b> on which the plurality of detectors <b>632</b>a-c are arranged along the curved surface <b>638</b>. The flexible substrate <b>680</b> conforms to the curved surface <b>638</b> by being mounted to a receive block housing <b>690</b> having the curved surface <b>638</b>. As illustrated in <figref idref="DRAWINGS">FIG. 6</figref>, the curved surface <b>638</b> includes the arrangement of the detectors <b>632</b>a-c curved along a vertical and horizontal axis of the receive block <b>630</b>.

<figref idref="DRAWINGS">FIGS. 7A and 7B</figref> illustrate an example lens <b>750</b> with an aspheric surface <b>752</b> and a toroidal surface <b>754</b>, in accordance with at least some embodiments described herein. <figref idref="DRAWINGS">FIG. 7B</figref> illustrates a cross-section view of the example lens <b>750</b> shown in <figref idref="DRAWINGS">FIG. 7A</figref>. The lens <b>750</b> can correspond to lens <b>150</b>, <b>250</b>, and <b>350</b> included in <figref idref="DRAWINGS">FIGS. 1-3</figref>. For example, the lens <b>750</b> can be configured to both collimate light incident on the toroidal surface <b>754</b> from a light source into collimated light propagating out of the aspheric surface <b>752</b>, and focus reflected light entering from the aspheric surface <b>752</b> onto a detector. The structure of the lens <b>750</b> including the aspheric surface <b>752</b> and the toroidal surface <b>754</b> allows the lens <b>750</b> to perform both functions of collimating and focusing described in the example above.

In some examples, the lens <b>750</b> defines a focal surface of the light propagating through the lens <b>750</b> due to the aspheric surface <b>752</b> and the toroidal surface <b>754</b>. In these examples, the light sources providing the light entering the toroidal surface <b>754</b> can be arranged along the defined focal surface, and the detectors receiving the light focused from the light entering the aspheric surface <b>752</b> can also be arranged along the defined focal surface.

By using the lens <b>750</b> that performs both of these functions (collimating transmitted light and focusing received light), instead of a transmit lens for collimating and a receive lens for focusing, advantages with respect to size, cost, and/or complexity can be provided.

<figref idref="DRAWINGS">FIG. 8A</figref> illustrates an example LIDAR device <b>810</b> mounted on a vehicle <b>800</b>, in accordance with at least some embodiments described herein. <figref idref="DRAWINGS">FIG. 8A</figref> shows a Right Side View, Front View, Back View, and Top View of the vehicle <b>800</b>. Although vehicle <b>800</b> is illustrated in <figref idref="DRAWINGS">FIG. 8</figref> as a car, other examples are possible. For instance, the vehicle <b>800</b> could represent a truck, a van, a semi-trailer truck, a motorcycle, a golf cart, an off-road vehicle, or a farm vehicle, among other examples.

The structure, function, and operation of the LIDAR device <b>810</b> shown in <figref idref="DRAWINGS">FIG. 8A</figref> is similar to the example LIDAR devices <b>100</b>, <b>200</b>, and <b>300</b> shown in <figref idref="DRAWINGS">FIGS. 1-3</figref>. For example, the LIDAR device <b>810</b> can be configured to rotate about an axis and determine a three-dimensional map of a surrounding environment of the LIDAR device <b>810</b>. To facilitate the rotation, the LIDAR device <b>810</b> can be mounted on a platform <b>802</b>. In some examples, the platform <b>802</b> may comprise a movable mount that allows the vehicle <b>800</b> to control the axis of rotation of the LIDAR device <b>810</b>.

While the LIDAR device <b>810</b> is shown to be mounted in a particular location on the vehicle <b>800</b>, in some examples, the LIDAR device <b>810</b> may be mounted elsewhere on the vehicle <b>800</b>. For example, the LIDAR device <b>810</b> may be mounted anywhere on top of the vehicle <b>800</b>, on a side of the vehicle <b>800</b>, under the vehicle <b>800</b>, on a hood of the vehicle <b>800</b>, and/or on a trunk of the vehicle <b>800</b>.

The LIDAR device <b>810</b> includes a lens <b>812</b> through which collimated light is transmitted from the LIDAR device <b>810</b> to the surrounding environment of the LIDAR device <b>810</b>, similarly to the lens <b>150</b>, <b>250</b>, and <b>350</b> described in <figref idref="DRAWINGS">FIGS. 1-3</figref>. Similarly, the lens <b>812</b> can also be configured to receive reflected light from the surrounding environment of the LIDAR device <b>810</b> that were reflected off one or more objects in the surrounding environment.

<figref idref="DRAWINGS">FIG. 8B</figref> illustrates a scenario where the LIDAR device <b>810</b> shown in <figref idref="DRAWINGS">FIG. 8A</figref> and scanning an environment <b>830</b> that includes one or more objects, in accordance with at least some embodiments described herein. In this example scenario, vehicle <b>800</b> can be traveling on a road <b>822</b> in the environment <b>830</b>. By rotating the LIDAR device <b>810</b> about the axis defined by the platform <b>802</b>, the LIDAR device <b>810</b> may be able to determine aspects of objects in the surrounding environment <b>830</b>, such as lane lines <b>824</b>a-b, other vehicles <b>826</b>a-c, and/or street sign <b>828</b>. Thus, the LIDAR device <b>810</b> can provide the vehicle <b>800</b> with information about the objects in the surrounding environment <b>830</b>, including distance, shape, color, and/or material type of the objects.

<figref idref="DRAWINGS">FIG. 9</figref> is a flowchart of a method <b>900</b> of operating a LIDAR device, in accordance with at least some embodiments described herein. Method <b>900</b> shown in <figref idref="DRAWINGS">FIG. 9</figref> presents an embodiment of a method that could be used with the LIDAR devices <b>100</b>, <b>200</b>, and <b>300</b>, for example. Method <b>900</b> may include one or more operations, functions, or actions as illustrated by one or more of blocks <b>902</b>-<b>912</b>. Although the blocks are illustrated in a sequential order, these blocks may in some instances be performed in parallel, and/or in a different order than those described herein. Also, the various blocks may be combined into fewer blocks, divided into additional blocks, and/or removed based upon the desired implementation.

In addition, for the method <b>900</b> and other processes and methods disclosed herein, the flowchart shows functionality and operation of one possible implementation of present embodiments. In this regard, each block may represent a module, a segment, or a portion of a manufacturing or operation process.

At block <b>902</b>, the method <b>900</b> includes rotating a housing of a light detection and ranging (LIDAR) device about an axis, wherein the housing has an interior space that includes a transmit block, a receive block, and a shared space, wherein the transmit block has an exit aperture, and wherein the receive block has an entrance aperture.

At block <b>904</b>, the method <b>900</b> includes emitting, by a plurality of light sources in the transmit block, a plurality of light beams that enter the shared space via a transmit path, the light beams comprising light having wavelengths in a wavelength range.

At block <b>906</b>, the method <b>900</b> includes receiving the light beams at a lens mounted to the housing along the transmit path.

At block <b>908</b>, the method <b>900</b> includes collimating, by the lens, the light beams for transmission into an environment of the LIDAR device.

At block <b>910</b>, the method <b>900</b> includes focusing, by the lens, the collected light onto a plurality of detectors in the receive block via a receive path that extends through the shared space and the entrance aperture of the receive block.

At block <b>912</b>, the method <b>900</b> includes detecting, by the plurality of detectors in the receive block, light from the focused light having wavelengths in the wavelength range.

For example, a LIDAR device such as the LIDAR device <b>200</b> can be rotated about an axis (block <b>902</b>). A transmit block, such as the transmit block <b>220</b>, can include a plurality of light sources that emit light beams having wavelengths in a wavelength range, through an exit aperture and a shared space to a lens (block <b>904</b>). The light beams can be received by the lens (block <b>906</b>) and collimated for transmission to an environment of the LIDAR device (block <b>908</b>). The collimated light may then reflect off one or more objects in the environment of the LIDAR device and return as reflected light collected by the lens. The lens may then focus the collected light onto a plurality of detectors in the receive block via a receive path that extends through the shared space and an entrance aperture of the receive block (block <b>910</b>). The plurality of detectors in the receive block may then detect light from the focused light having wavelengths in the wavelength range of the emitted light beams from the light sources (block <b>912</b>).

Within examples, devices and operation methods described include a LIDAR device rotated about an axis and configured to transmit collimated light and focus reflected light. The collimation and focusing can be performed by a shared lens. By using a shared lens that performs both of these functions, instead of a transmit lens for collimating and a receive lens for focusing, advantages with respect to size, cost, and/or complexity can be provided. Additionally, in some examples, the shared lens can define a curved focal surface. In these examples, the light sources emitting light through the shared lens and the detectors receiving light focused by the shared lens can be arranged along the curved focal surface defined by the shared lens.

It should be understood that arrangements described herein are for purposes of example only. As such, those skilled in the art will appreciate that other arrangements and other elements (e.g. machines, interfaces, functions, orders, and groupings of functions, etc.) can be used instead, and some elements may be omitted altogether according to the desired results. Further, many of the elements that are described are functional entities that may be implemented as discrete or distributed components or in conjunction with other components, in any suitable combination and location, or other structural elements described as independent structures may be combined.

While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims, along with the full scope of equivalents to which such claims are entitled. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.