Laser scanning device

Abstract

The utility model provides a laser scanning device, comprising a tunable laser capable of outputting a laser beam with continuously variable frequency under the control of an electric control signal; the collimating lens is used for shaping and focusing the laser beams output by the tunable laser; and the dispersion optical element is used for deflecting the incident laser beams with different frequencies at different angles in the vertical direction to generate vertical scanning laser beams. The laser scanning device further comprises a diffractive optical element which is used for enabling the vertical scanning laser beam to horizontally deflect. According to the utility model, the pointing direction of the laser beam is changed along with the change of the frequency by utilizing the optical dispersion effect, so that the beam steering without a mechanical moving part is realized. The structure does not need mechanical moving parts, can realize high-frequency light beam scanning, and is suitable for high-resolution vertical scanning. By rotating the dispersion component or adding a diffractive optical component, the surface scanning of the laser beam can be conveniently realized.

Description

Technical Field

[0001] This utility model relates to laser scanning devices, and more particularly to laser scanners implemented using tunable semiconductor lasers and dispersive optical elements. Background Technology

[0002] LiDAR, as an advanced sensor technology, has been widely used in autonomous driving, surveying, robotics, and other fields in recent years. By emitting laser beams and receiving reflected signals, it can accurately perceive the three-dimensional information of the surrounding environment, providing reliable environmental perception capabilities for various application scenarios. The scanning system is a key component of LiDAR's environmental perception capabilities. It emits the laser beam in different directions to cover a larger detection area and determines important performance indicators such as the LiDAR's scanning range, scanning speed, and resolution.

[0003] LiDAR scanning methods are mainly divided into two types: mechanical scanning and solid-state scanning. Mechanical scanning LiDAR uses the rotation or vibration of a mechanical structure to drive a laser emitter or reflector, emitting a laser beam in different directions to scan the surrounding environment. Its advantages include a wide scanning range, mature technology, and relatively low cost. Its disadvantages include complex structure, large size, susceptibility to mechanical wear, and difficulty meeting automotive-grade requirements in the field of autonomous driving. Solid-state scanning LiDAR has no macroscopic moving mechanical parts; it mainly relies on electronic devices to control the direction of the laser beam to achieve the scanning function. Due to its small size, high stability, fast scanning speed, and long lifespan, it has become a major research direction in recent years.

[0004] This invention addresses current market demands by proposing a laser scanning device that utilizes a tunable semiconductor laser and dispersive optical elements to achieve rapid scanning of the laser beam along the vertical axis, thereby enabling two-dimensional planar scanning. It boasts advantages such as simple structure, small size, and stable performance. Utility Model Content

[0005] This utility model proposes a laser scanning device, comprising:

[0006] A tunable laser that can output a laser beam with a continuously variable frequency under the control of an electronic signal;

[0007] A collimating lens is used to shape and focus the laser beam output from a tunable laser.

[0008] A dispersive optical element is used to deflect incident laser beams of different frequencies at different angles in the vertical direction to generate a vertically scanning laser beam.

[0009] The laser scanning device further includes a diffractive optical element for horizontally deflecting the vertical scanning laser beam.

[0010] The tunable laser further includes a miniature DC motor or stepper motor that drives the dispersive and diffractive optical elements to rotate, and a closed-loop feedback control system including an encoder.

[0011] The collimating lens is any one or a combination of several of the following: single-mode optical fiber, convex lens, transverse convex lens, and longitudinal convex lens.

[0012] The dispersive optical element is an optical prism made of quartz glass.

[0013] The diffractive optical element consists of a substrate and micro / nano structures etched on the surface. The transparent substrate is quartz glass, and the micro / nano structures are etched on the substrate surface using photolithography.

[0014] This invention utilizes the optical dispersion effect to change the direction of a laser beam with frequency, thereby achieving beam steering without mechanical moving parts. This structure eliminates the need for moving mechanical components, enabling high-frequency beam scanning and making it suitable for high-resolution vertical scanning. By rotating the dispersion component or adding a diffraction optics component, planar scanning of the laser beam can also be easily achieved. It boasts advantages such as simple structure, small size, and stable performance.

[0015] Other features and advantages of this utility model will become clearer after reading the detailed description of the embodiments of this utility model in conjunction with the accompanying drawings. Attached Figure Description

[0016] To clearly illustrate the technical solution and embodiments of this utility model, the accompanying drawings are briefly described below. It should be noted that the drawings are primarily intended to explain the interconnections, structural features, and advantages of the various components of the device, and are not drawn to scale according to the actual dimensions of the device. Obviously, the drawings only relate to a limited set of embodiments and should not be construed as limiting the present utility model. Those skilled in the art can easily obtain new embodiments through formal variations based on these drawings.

[0017] Figure 1 This is a schematic diagram of a commonly used laser scanning structure;

[0018] Figure 2 This is a schematic diagram of the structure of one embodiment of the present utility model;

[0019] Figure 3 This is the output spectrum of a tunable semiconductor laser in one embodiment of the present invention. Detailed Implementation

[0020] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings.

[0021] The scanning system is a key component for lidar to achieve environmental perception. Currently, the industry's solution is to use the combination of a laser emission source and an optical scanning structure to emit laser beams in different directions to achieve coverage of the detection area. Figure 1 A schematic diagram of a scanning structure employing a dual MEMS galvanometer scheme is presented. In the diagram, A1 is a laser source, whose emitted laser light is focused and shaped by a collimating lens A2 before entering a micro-electromechanical system (MEMS) mirror A3. A micro-energy source drives the reciprocating deflection angle of the mirror A3, achieving rapid movement of the reflected beam and completing a lateral line scan in a very short time. Then, a second MEMS mirror A4 is placed in the reflected light path of the MEMS mirror A3. A micro-energy source drives the reciprocating deflection angle of the mirror A4, achieving rapid movement of the reflected beam and completing a longitudinal scan of the laser beam, thus ultimately achieving a planar scan of the laser beam. Despite its advantages of small size and low power consumption, the MEMS galvanometer scanning scheme also has disadvantages such as high cost and limited scanning angle.

[0022] This utility model proposes a novel laser beam scanning device, the structural schematic diagram of which is shown below. Figure 2 As shown in the diagram, laser source B1 emits a frequency-tunable laser beam, the frequency of which can be adjusted in real time via a control terminal electrical signal. After being shaped and focused, the laser beam emitted from source B1 is incident on a dispersive optical element B2, such as a prism. According to optical principles, light of different frequencies incident on dispersive optical element B2 will be deflected at different angles, forming multiple vertical scanning lines as shown in the diagram. Laser source B1 is a tunable laser, such as a V-cavity tunable laser or a grating distributed feedback laser (DBR). By adjusting the laser's electrical control parameters, the frequency of the output laser beam can be rapidly switched. Through refraction by dispersive optical element B2, high-frequency beam scanning is achieved in the vertical (fast axis) direction. Figure 3 The spectrum of the 1550nm band output by the tunable laser is given. As can be seen from the figure, the laser can continuously output scanning signals in the 1515nm-1550nm band under the control of the electronic control signal.

[0023] The collimating lens A2 described above is any one or a combination of several of the following: single-mode optical fiber, convex lens, transverse convex lens, and longitudinal convex lens. The dispersive optical element B2 described above is made of quartz glass.

[0024] To achieve planar scanning of the laser beam, this can be accomplished by rotating the dispersive optical element B2, or by rotating a diffractive optical element (DOE). A DOE is an optical element that uses the principle of diffraction to control the direction of a laser beam. Its working principle is to change the phase distribution of the incident light, causing the beam to diffract in a specific direction, thereby achieving beam redirection. The aforementioned rotation is driven by a miniature DC motor or a stepper motor. The selection of the motor needs to consider torque, speed, and accuracy, and a closed-loop control system (such as encoder feedback) is used to ensure the precision of the rotation angle and speed.

[0025] The aforementioned DOE consists of a transparent substrate and micro / nano structures etched on its surface. The transparent substrate is quartz glass, and the micro / nano structures obtained through simulation calculations are etched on its surface using photolithography.

[0026] This invention utilizes the optical dispersion effect to change the direction of a laser beam with frequency, thereby achieving beam steering without mechanical moving parts. This structure eliminates the need for mechanical moving parts, enabling high-frequency beam scanning and making it suitable for high-resolution vertical scanning.

[0027] The description of this utility model is given for illustrative purposes only and is not intended to be exhaustive or to limit the utility model to the disclosed forms. The embodiments were chosen and described to better illustrate the principles and practical applications of the utility model, and to enable those skilled in the art to understand the utility model and design various embodiments with various modifications suitable for a particular purpose. All new embodiments that fall within the basic concept, construction principles, and spirit of this utility model, and are achieved through simple variations, modifications, equivalent substitutions, or improvements, should be included within the scope of protection of this utility model. The scope of this utility model is defined by the appended claims.

Claims

1. A laser scanning device, characterized in that, The laser scanning device includes: A tunable laser that can output a laser beam with a continuously variable frequency under the control of an electronic signal; A collimating lens is used to shape and focus the laser beam output from a tunable laser. A dispersive optical element is used to deflect incident laser beams of different frequencies at different angles in the vertical direction to generate a vertically scanning laser beam.

2. The laser scanning device according to claim 1, characterized in that, The laser scanning device further includes a diffractive optical element for horizontally deflecting the vertical scanning laser beam.

3. The laser scanning device according to claim 1, characterized in that, The tunable laser further includes a miniature DC motor or stepper motor that drives the dispersive and diffractive optical elements to rotate, and a closed-loop feedback control system including an encoder.

4. The laser scanning device according to claim 2, characterized in that, The collimating lens is any one or a combination of several of the following: single-mode optical fiber, convex lens, transverse convex lens, and longitudinal convex lens.

5. The laser scanning device according to claim 3, characterized in that, The dispersive optical element is an optical prism made of quartz glass.

6. The laser scanning apparatus according to any one of claims 2-5, characterized in that, The diffractive optical element consists of a substrate and micro / nano structures etched on the surface. The transparent substrate is quartz glass, and the micro / nano structures are etched on the substrate surface using photolithography.

Images