Patent Application
20220026198
Modem vehicles are often equipped with sensors designed to detect objects and landscape features around the vehicle in real-time to enable technologies such as lane change assistance, collision avoidance, and autonomous driving. A commonly used sensor is a light detection and ranging (LiDAR) system.
A LiDAR system may include a light source, also referred to as a transmission module, and a light detection system, also referred to as a receiver module, to estimate distances to environmental features (e.g., pedestrians, vehicles, structures, plants, etc.). The transmission module may include a laser module and an optical lens assembly. The laser module may include a circuit board mounted laser configured to emit a laser beam that is optically aligned with the optical lens assembly. The emitted laser beam is used to illuminate a target and the LiDAR system measures the time it takes for the transmitted laser beam to arrive at the target and then return to the receiver module. In some LiDAR systems, the laser beam may be steered across a region of interest according to a scanning pattern to generate a “point cloud” that includes a collection of data points corresponding to target points in the region of interest. The data points in the point cloud may be dynamically and continuously updated, and may be used to estimate, for example, a distance, dimension, and location of an object relative to the LiDAR system, often with very high fidelity (e.g., within about 5 cm) due to the precision of the optical alignment of the components.
In embodiments, a method of optically aligning a laser module with an optical lens assembly coupled to a chassis in a LiDAR system may include movably coupling a first alignment block to the chassis with a first screw fixedly coupled to the chassis. The method may further include, applying a first portion of adhesive on the first alignment block and the first screw, applying a second portion of adhesive on the first alignment block and the laser module. The method may further include, applying a non-solid gap filler between the laser module and the chassis, orienting the laser module relative to the optical lens assembly, with the non-solid gap filler between the chassis and the laser module, to an optically aligned orientation wherein a path of a laser beam emitted from the laser module is oriented with an optical path in the optical lens assembly. The method may further include, curing the non-solid gap filler between the chassis and the laser module, curing the first portion of adhesive in order to fixedly couple the first alignment block to the first screw and the chassis, and curing the second portion of adhesive, after curing the first portion of adhesive, with the laser module in the optically aligned orientation, in order to fixedly couple the laser module to the first alignment block and the chassis in the optically aligned orientation.
In embodiments, the first alignment block may be movably coupled to the chassis so that the first alignment block is translatable relative to the chassis. The method may further include translating relative to the chassis after coupling the first alignment block to the chassis and prior to curing the first portion of adhesive. In embodiments, the first alignment block may include a rectangular prism body defining a first elongated slot and a second elongated slot. In embodiments, movably coupling the first alignment block to the chassis with the first screw may include positioning the first screw within the first elongated slot. In embodiments, the method may include securing the first alignment block to the chassis with a second screw positioned within the second elongated slot. In embodiments, the first and second elongated slots and the first and second screws may be configured to allow the first alignment block to translate in a single degree of freedom relative to the chassis. In embodiments, the method may include translating the first alignment block relative to the first and second screws after coupling the first alignment block to the chassis and prior to curing the first portion of adhesive.
In embodiments, the first and second screws may be shoulder screws each comprising a threaded end, an unthreaded central portion, and a head. The first and second elongated slots may each define a depth, a length and a width less than the length. The unthreaded central portions of each of the first and the second screws may define a first diameter corresponding to the width of the first and second elongated slots. The heads of each of the first and second screws may define a second diameter greater than the first diameter and greater than the widths of the first and second elongated slots.
In embodiments, the heads of each of the first and second screws may include a textured side wall surface, and applying the first portion of adhesive on the first alignment block and the first screw may include applying the first portion on the textured side wall surface of the first screw. In embodiments, the first alignment block may define a recess between the first elongated slot and the second elongated slot, and applying the first portion of adhesive on the first alignment block and the first screw may include applying the first portion in the recess. In embodiments, the first alignment block may define a top surface and a recessed surface offset from the top surface, the heads of the first and second screws may project away from the top surface of the secured first alignment block, applying the second portion of adhesive on the first alignment block and the laser module may include applying the second portion of adhesive onto the recessed surface.
In embodiments, the laser module may include, a second chassis, a circuit board fixedly coupled to the second chassis, and a laser fixedly coupled to the circuit board. Applying the non-solid gap filler between the laser module and the chassis may include applying the non-solid gap filler between the second chassis and the chassis.
In embodiments, the non-solid gap filler may not be applied between the first alignment block and the chassis. In embodiments, the first portion of adhesive and the second portion of adhesive may not contact the non-solid gap filler. In embodiments, curing the non-solid gap filler may be performed simultaneously with or after orienting the laser module to the optically aligned orientation. In embodiments, curing the first portion of adhesive may be performed prior to orienting the laser module to the optically aligned orientation.
In embodiments, the method may include securing a second alignment block to the chassis with a third screw fixedly coupled to the chassis, applying a third portion of adhesive on the second alignment block and the third screw, applying a fourth portion of adhesive on the second alignment block and the laser module, wherein the first alignment block may be positioned on a first side of the laser module and the second alignment block is positioned on a second side of the laser module perpendicular to the first side of the laser module, curing the third portion of adhesive in order to fixedly couple the second alignment block to the third screw and the chassis, and curing the fourth portion of adhesive, after curing the third portion of adhesive, with the laser module in the optically aligned orientation, in order to fixedly couple the laser module to the second alignment block and the chassis in the optically aligned orientation.
In embodiments, a transmission module in a LiDAR system may include, a chassis, an optical lens assembly coupled to a chassis, a first alignment block, a first screw fixedly coupled to the chassis and extending through a first elongated slot of the first alignment block, and a laser module. The first screw may be fixedly coupled to the first alignment block with a first portion of adhesive. A second portion of adhesive may be positioned between the laser module and the first alignment block so that the laser module is fixedly coupled to the first alignment block. The first and second portions of adhesive may maintain the laser module in an optically aligned orientation with the optical lens assembly wherein a path of a laser beam emitted from the laser module is oriented with an optical path in the optical lens assembly.
In embodiments, the first screw and the first elongated slot may be configured to allow the first alignment block to translate relative to the chassis prior to an application of the first portion of adhesive. In embodiments, the transmission module may include a second screw fixedly coupled to the chassis and extending through a second elongated slot of the first alignment block. The second screw may be fixedly coupled to the first alignment block with a third portion of adhesive. The first alignment block may include a rectangular prism body defining the first elongated slot and the second elongated slot.
In embodiments, the first and second screws may be shoulder screws each comprising a threaded end, an unthreaded central portion, and a head. The first and second elongated slots each may define a depth, a length and a width less than the length. The unthreaded central portions of each of the first and the second screws may define a first diameter corresponding to the width of the first and second elongated slots. The heads of each of the first and second screws may define a second diameter greater than the first diameter and greater than the widths of the first and second elongated slots.
In embodiments, the heads of each of the first and second screws may include a textured side wall surface, and the first portion of adhesive may be bonded to the first alignment block and the textured side wall surface of the first screw. The first alignment block may include a top surface defining a recess, and the first portion of adhesive may be bonded to the first alignment block within the recess and bonded to the first screw. The first alignment block may define a top surface and a recessed surface offset from the top surface, and the second portion of adhesive may be bonded to the recessed surface and a second chassis of the laser module.
This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification of this disclosure, any or all drawings, and each claim.
The foregoing, together with other features and examples, will be described in more detail below in the following specification, claims, and accompanying drawings.
The features of the various embodiments described above, as well as other features and advantages of certain embodiments of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:
FIG. IA shows a portion of a transmission module of an autonomous vehicle LiDAR assembly including a chassis, a laser module, and alignment blocks, according to certain embodiments;
Throughout the drawings, it should be noted that like reference numbers are typically used to depict the same or similar elements, features, and structures.
Aspects of the present disclosure relate generally to aligning a laser module relative to an optical lens assembly, and securing the laser module in an optically aligned orientation using one or more alignment blocks fixedly coupled to the laser module and fixedly coupled to a chassis to which the optical lens assembly is fixedly coupled. The chassis, laser module, and optical lens assembly may be part of a LiDAR assembly, according to certain embodiments.
In the following description, various examples of laser module optical alignment and securing techniques are described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the embodiments. However, it will be apparent to one skilled in the art that certain embodiments may be practiced or implemented without every detail disclosed. Furthermore, well-known features may be omitted or simplified in order to prevent any obfuscation of the novel features described herein.
The following high-level summary is intended to provide a basic understanding of some of the novel innovations depicted in the figures and presented in the corresponding descriptions provided below. Generally, aspects of the invention are directed to implementations of fixedly coupling a laser module to a chassis in an optically aligned orientation with an optical lens assembly coupled to the chassis. For example, a Light Detection and Ranging (LiDAR) assembly of an autonomous vehicle may include a transmission module (TX), or combination transmission and receiving module (TX/RX), including a laser module. The laser module comprises a laser module chassis, a circuit board coupled to the laser module chassis, and a laser coupled to the circuit board, for example a shown in
The present technology relates to the use of alignment blocks and adhesives to fixedly couple the laser module to the chassis of the transmission module in an optically aligned orientation. Specifically, one or more alignment blocks may be movably coupled to the chassis of the transmission module in order to have one or mode degrees of freedom prior to application of adhesive, for example as shown in
The transmission module 100 further comprises an optical lens assembly 104. The laser module 200 is oriented in an optically aligned orientation so that a path of a laser beam emitted from the laser module is oriented with an optical path in the optical lens assembly 104. The precise alignment of the laser module allows for the LiDAR assembly to generate precise measurements.
As will be discussed in greater detail below, the shoulder screws 400 may not directly fixedly couple the alignment blocks 500 to the chassis 101. The shoulder screws 400 may movably couple the alignment blocks to the chassis 101 and therefore allows the alignment blocks to be moved relative to the chassis in at least one degree of freedom, for example translation toward and away from the laser module 200. Not shown in
As shown in FIGS. IA and 1B, the laser module 200 may not be directly coupled to the chassis 101 with mechanical fasteners. As will be discussed in greater detail below, the laser module 200 may be supported above the mounting surface 102 of the chassis 101 with a gap filler, which may be applied as a non-solid gap filler. Not shown in
As shown in
The laser module chassis 201 may define a lens bracket 205 housing a lens through which a laser beam emitted from the laser 204 passes prior to entering the optical lens assembly 104. As shown in
In embodiments, the alignment block 500 may include features for receiving adhesive in order to increase the bond strength of an adhesive bonded to the alignment block 500. In embodiments, for example as shown in
As shown in
With the alignment blocks 500 movably coupled to the chassis 101, a laser module 200 may be positioned adjacent the alignment blocks 500, as shown for example in
To optically align the laser module 200 relative to the optical lens assembly 104, the laser module 200 may be manipulated about one or more of the six degrees of freedom, i.e. xyz translation and xyz rotation, and an output beam from the optical lens assembly 104 may be observed to determine that the laser module 200 is in an optically aligned orientation. In embodiments, an alignment jig may be used to orient the optical lens assembly to a position and maintain the optical lens assembly in the aligned position. Manipulation of the laser module may cause a redistribution of the uncured non-solid gap filler between the laser module chassis 201 and the mounting surface 102 of the chassis 101 so that no air gaps are present after curing in order to maintain the thermal path.
Prior to, or during, the manipulation of the laser module 200 for optical alignment, the alignment blocks 500 may be translated to a position to be directly adjacent to the laser module 200 in the optically aligned orientation. As shown for example in
As shown for example in
Examples of adhesives 702 and 703 to be applied between the shoulder screws 400 and the alignment blocks 500, and between the alignment blocks 500 and the laser module chassis 201 include for example Henkel Loctite Eccobond UV glue or similar adhesives. The curing process for the adhesives may be one or more of UV curing, and thermal curing.
Other variations are within the spirit of the present disclosure. Thus, while the disclosed techniques are susceptible to various modifications and alternative constructions, certain illustrated examples thereof are shown in the drawings and have been described above in detail. It should be understood, however, that there is no intention to limit the disclosure to the specific form or forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions and equivalents falling within the spirit and scope of the disclosure, as defined in the appended claims. For instance, any of the examples, alternative examples, etc., and the concepts thereof may be applied to any other examples described and/or within the spirit and scope of the disclosure.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the disclosed examples (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. The term “connected” is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening. The phrase “based on” should be understood to be open-ended, and not limiting in any way, and is intended to be interpreted or otherwise read as “based at least in part on,” where appropriate. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate examples of the disclosure and does not pose a limitation on the scope of the disclosure unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosure.
