Laser radar module

Abstract

A laser radar module includes a laser emitter, a rotatable support, a first reflective surface, a second reflective surface, a photosensor, and a plurality of reflectors. The laser emitter emits a laser beam, and the rotatable support has a first side and a second side opposite to each other. The first reflective surface is disposed on the first side of the rotatable support and is used to reflect the laser beam to the outside. The second reflective surface is disposed on the second side of the rotatable support and is used to reflect the laser beam reflected by an external object. The photosensor is positioned in the path of the laser beam reflected by the second reflective surface. The reflectors sequentially reflect the laser beam emitted by the laser emitter to the first reflective surface.

Description

[Technical Field]

[0001] This invention relates to an optical module, and more particularly to a laser radar module. [Previous Technology]

[0002] LiDAR is a technology that uses laser pulses to measure the distance between an object and a sensor. Its working principle involves emitting laser pulses, measuring the time required for the laser pulses to reflect back from the target object, and combining this with the speed of light to calculate the distance. This data is then converted into a three-dimensional point cloud map, which further generates the shape and spatial distribution of the object.

[0003] The main components of a laser radar include a laser transmitter, a receiver, an optical scanning system, and a processing unit. The laser transmitter generates laser pulses, the receiver receives reflected laser signals, the optical scanning system assists in scanning the environment (usually a rotating mechanism or a multi-line laser system), and the processing unit converts the measured data into useful three-dimensional images or models.

[0004] Mechanical rotating laser radar is a classic and widely used laser radar structure. It operates like a rotating laser light source, constantly scanning the surrounding environment and capturing details in three-dimensional space.

[0005] Mechanical rotating laser radar achieves 360-degree omnidirectional scanning through an internal rotating structure. The laser transmitter emits a laser pulse, which is guided in a specific direction by a reflector (usually a rotating reflector). After the scan is completed, the receiver captures the laser signal reflected back from the target.

[0006] The key component for rotation is usually a high-speed rotating reflector or the entire laser transmitting and receiving module. As the rotation angle changes, the laser beam gradually sweeps across the entire environment, eventually constructing a complete 360-degree point cloud image.

[0007] However, if the entire laser transmitting and receiving module is rotated, the motor load will be too heavy, resulting in higher energy consumption. If a rotating mirror is used, the existing technology places the laser transmitter and sensor on the same side of the rotating mirror. This causes the laser transmission path and the light receiving path to reverse positions when the mirror rotates 180 degrees, leading to positional errors in environmental detection. To solve this problem, a galvanometer can be placed on the optical path, or an algorithm can be used for correction, but these methods increase the cost of the laser radar. [Summary of the Invention]

[0008] The present invention provides a laser radar module that has the advantages of low power consumption, high accuracy and low cost.

[0009] One embodiment of the present invention provides a laser radar module, including a laser emitter, a rotatable support, a first reflective surface, a second reflective surface, a photosensor, and a plurality of reflectors. The laser emitter emits a laser beam, and the rotatable support has a first side and a second side opposite to each other. The first reflective surface is disposed on the first side of the rotatable support, positioned in the path of the laser beam, and is used to reflect the laser beam to the outside. The second reflective surface is disposed on the second side of the rotatable support, positioned in the path of a laser beam reflected by an external object, and is used to reflect the laser beam reflected by the object. The photosensor is positioned in the path of the laser beam reflected by the second reflective surface and is used to sense the laser beam. These reflectors are used to sequentially reflect the laser beam emitted by the laser emitter to the first reflective surface, wherein the laser emitter and the photosensor are located on the same side of the rotatable support. The rotatable support is adapted to rotate and drive the first reflective surface and the second reflective surface to rotate, so that the laser beam reflected by the first reflective surface scans the outside world in different directions, and the second reflective surface receives laser beams from the outside world from different directions.

[0010] In the laser radar module of the embodiment of the present invention, a first reflective surface is disposed on a first side of a rotatable support and is used to reflect a laser beam to the outside world, and a second reflective surface is disposed on a second side of the rotatable support and is used to reflect a laser beam reflected by an external object. The rotatable support is adapted to rotate, thereby causing the first and second reflective surfaces to rotate, so that the laser beam reflected by the first reflective surface scans the outside world in different directions, and the second reflective surface receives laser beams from different directions from the outside world. With this configuration, some components (i.e., the rotatable support) in the laser radar module can be rotated, and during the rotation, the optical path of the laser beam emitted to the outside world and the optical path of the laser beam received from the outside world will not be reversed. Therefore, the laser radar module of the embodiment of the present invention can have the advantages of lower power consumption, higher accuracy, and lower cost. Furthermore, in the laser radar module of the embodiments of the present invention, since these reflectors are used to sequentially reflect the laser beam emitted by the laser transmitter to the first reflective surface, the laser transmitter and the photosensitive sensor can be located on the same side of the rotatable support. In this way, a simple circuit connection method can be used to simultaneously power the laser transmitter and the photosensitive sensor without the problem that the circuit needs to cross the rotatable support and make it difficult to power supply.

Implementation Method

[0012] Figure 1A is a perspective view of a laser radar module according to an embodiment of the present invention, Figure 1B is a side view of the laser radar module of Figure 1A, and Figure 1C is a partial perspective view of the laser radar module of Figure 1A from another perspective. Referring to Figures 1A, 1B, and 1C, the laser radar module 100 of this embodiment includes a laser emitter 110, a rotatable support 120, a first reflective surface 130, a second reflective surface 140, a photosensor 150, and a plurality of reflectors 220. The laser emitter 110 is used to emit a laser beam 112, and the rotatable support 120 has a first side S1 and a second side S2 facing each other. The first reflective surface 130 is disposed on the first side S1 of the rotatable support 120, arranged in the path of the laser beam 112, and is used to reflect the laser beam 112 to the outside. The second reflective surface 140 is disposed on the second side S2 of the rotatable support 120, positioned in the path of the laser beam 112 reflected by the external object 50, and is used to reflect the laser beam 112 reflected by the object 50. A photosensor 150 is disposed in the path of the laser beam 112 reflected by the second reflective surface 140, and is used to sense the laser beam 112. These reflectors 220 are used to sequentially reflect the laser beam 112 emitted by the laser emitter 110 to the first reflective surface 130, and the laser emitter 110 and the photosensor 150 are located on the same side of the rotatable support 120. In this embodiment, these reflectors 220 are, for example, mirrors. The rotatable support 120 is adapted to rotate to drive the first reflective surface 130 and the second reflective surface 140 to rotate, so that the laser beam 112 reflected by the first reflective surface 130 scans the outside world in different directions, and the second reflective surface 140 receives the laser beam 112 from the outside world from different directions.

[0013] In this embodiment, the laser radar module 100 forms a time of flight sensor. By calculating the time difference or phase difference between the laser beam 112 emitted by the laser transmitter 110 and the laser beam 112 received by the light sensor 150, the distance of the surrounding objects 50 can be calculated. When the laser beam 112 scans the outside world in different directions, a point cloud map containing the position and distance of each object in the external environment can be obtained to achieve the sensing of the surrounding environment.

[0014] In the laser radar module 100 of this embodiment, the first reflective surface 130 is disposed on the first side S1 of the rotatable support 120 and is used to reflect the laser beam 112 to the outside. The second reflective surface 140 is disposed on the second side S2 of the rotatable support 120 and is used to reflect the laser beam 112 reflected by the external object 50. The rotatable support 120 is adapted to rotate to drive the first reflective surface 130 and the second reflective surface 140 to rotate, so that the laser beam 112 reflected by the first reflective surface 130 scans the outside in different directions, and the second reflective surface 140 receives the laser beam 112 from different directions. With this configuration, some components (i.e., the rotatable support 120) in the laser radar module 100 can rotate without reversing the optical path of the laser beam 112 emitted to the outside and the optical path of the laser beam 112 received from the outside. This eliminates the need for additional costs associated with using galvanometers positioned on the optical path or algorithms for correction. Therefore, the laser radar module 100 of this embodiment combines advantages such as lower power consumption, higher accuracy, and lower cost. In this embodiment, the first reflecting surface 130 can be the reflecting surface of a mirror, and the second reflecting surface 140 can be the reflecting surface of another mirror.

[0015] In this embodiment, the laser emitter 110 emits a laser beam 112 in a horizontal direction D1 away from the photosensor 150. A first reflector 220a among these reflectors 220 is used to reflect the laser beam 112 from the laser emitter 110 in a vertical direction D2 to the first side S1. A second reflector 220b and a third reflector 220c among these reflectors 220 sequentially reflect the laser beam 112 from the first reflector 220a to the first reflecting surface 130. In the laser radar module 100 of this embodiment, since these reflectors 220 are used to sequentially reflect the laser beam 112 emitted by the laser emitter 110 to the first reflective surface 130, the laser emitter 110 and the photosensor 150 can be located on the same side of the rotatable support 120 (for example, both located on the second side S2). In this way, a simple circuit connection method can be used to simultaneously power the laser emitter 110 and the photosensor 150 without the problem that the circuit needs to cross the rotatable support 120 and is difficult to power.

[0016] Figure 2A shows the diffuser in Figures 1A and 1B dispersing the laser beam into a surface light source, and Figure 2B shows the diffuser in Figures 1A and 1B dispersing the laser beam into a linear light source. Referring to Figures 1A, 1B, 2A, and 2B, in this embodiment, the laser radar module 100 includes a diffuser 160 disposed in the path of the laser beam 112, located between the laser emitter 110 and the first reflector 220a closest to the laser emitter 110 among these reflectors 220, and used to disperse the laser beam 112 into a surface light source 112' (as shown in Figure 2A) or a linear light source 112" (as shown in Figure 2B). In this embodiment, the laser emitter 110 is, for example, a laser diode, and the photosensor 150 is, for example, an image sensor, which may have multiple pixels arranged in a one-dimensional or two-dimensional array.

[0017] Referring again to Figures 1A to 1C, in this embodiment, the laser radar module 100 includes a plurality of magnets 170, a substrate 180, and a plurality of coils 190. The magnets 170 are arranged around a rotatable support 120. The substrate 180 has an opening 182 for accommodating one end of the rotatable support 120 and the magnets 170. The coils 190 are disposed at the edge of the opening 182, and the coils 190 are adapted to be energized to generate a magnetic force on the magnets 170, thereby causing the rotatable support 120 to rotate.

[0018] In this embodiment, the first reflective surface 130 and the second reflective surface 140 are tilted relative to the substrate 180 in two opposite directions at an angle greater than 35 degrees and less than 55 degrees. For example, in one embodiment, the first reflective surface 130 and the second reflective surface 140 are tilted relative to the substrate 180 in two opposite directions at 45 degrees. In this embodiment, the included angle θ1 between the first reflective surface 130 and the second reflective surface 140 is greater than 0 degrees and less than 180 degrees. In one embodiment, the included angle θ1 between the first reflective surface 130 and the second reflective surface 140 is greater than 70 degrees and less than 110 degrees. For example, when the first reflective surface 130 and the second reflective surface 140 are tilted relative to the substrate 180 in two opposite directions at 45 degrees, the included angle θ1 between the first reflective surface 130 and the second reflective surface 140 is equal to 90 degrees.

[0019] In this embodiment, the laser radar module 100 includes a base 270, wherein both the light sensor 150 and the laser emitter 110 are disposed on the base 270. The light sensor 150 is located between the base 270 and the second reflective surface 140, and the second reflective surface 140 is located between the light sensor 150 and the first reflective surface 130. In addition, the rotatable support 120 can rotate 360 ​​degrees around the axis A1 (as shown in FIG. 1B), wherein the extension direction of the axis A1 can be from the light sensor 150 toward the first reflective surface 130.

[0020] In this embodiment, the laser radar module 100 includes a first optical element 250 and a second optical element 260. The first optical element 250 is disposed in the path of the laser beam 112 and is located between the laser emitter 110 and one of the reflectors 220 closest to the laser emitter 110 (such as the first reflector 220a) to collimate the laser beam 112. The second optical element 260 is disposed in the path of the laser beam 112 and is located between the second reflective surface 140 and the photosensor 150 to converge the laser beam 112 from the external object 50 onto the photosensor 150. In this embodiment, the first optical element 250 and the second optical element 260 may each be a lens, for example, and may include at least one lens.

[0021] In this embodiment, the laser radar module includes a top cover 210, and at least a portion of the reflectors 220 (e.g., second reflector 220b and third reflector 220c) are disposed on the top cover 210. In this embodiment, the laser radar module 100 may include an annular side cover 280, connecting the top cover 210 and the base 270, and surrounding the laser emitter 110, the rotatable support 120, the first reflective surface 130, the second reflective surface 140, the photosensor 150, and these reflectors 220. The annular side cover 280 may be made of a material that can be penetrated by the laser beam 112. In one embodiment, the wavelength of the laser beam 112 is, for example, 905 nanometers or 940 nanometers.

[0022] Figure 3 is a partial perspective view of a laser radar module according to another embodiment of the present invention. Referring to Figure 3, the laser radar module of this embodiment is similar to the laser radar module 100 of Figure 1B, and the main differences between the two are as follows. In the laser radar module 100 of Figure 1B, the laser emitter 110 and the photosensor 150 are respectively disposed on two different circuit boards 310 and 320, and the circuit boards 310 and 320 are electrically connected to each other. In one embodiment, the circuit boards 310 and 320 are perpendicular to each other. However, in the laser radar module of this embodiment, the laser emitter 110 and the photosensor 150 are disposed on the same circuit board 310d. The laser emitter 110 emits a laser beam 112 toward the first side S1. The reflectors 220 disposed on the first side S1 sequentially reflect the laser beam 112 toward the first reflective surface 130. For example, the laser beam 112 is sequentially reflected toward the first reflective surface 130 by the first reflector 220h and the second reflector 220i.

[0023] Figure 4 is a partial perspective view of a laser radar module according to another embodiment of the present invention. Referring to Figure 4, the laser radar module of this embodiment is similar to the laser radar module of Figure 3, and the main differences between the two are as follows. In the laser radar module of this embodiment, the reflectors 220 include a first reflector 220d and a second reflector 220e disposed on the second side S2, and a third reflector 220f and a fourth reflector 220g disposed on the first side S1. The laser beam 112 emitted by the laser emitter 110 is sequentially directed toward the first reflector 220d (e.g., directed toward the first reflector 220d in the vertical direction D2) on the first side S1, reflected by the first reflector 220d in the horizontal direction D1 to the second reflector 220e, reflected by the second reflector 220e to the third reflector 220f (e.g., reflected toward the third reflector 220f in the vertical direction D2, reflected by the third reflector 220f to the fourth reflector 220g, and reflected by the fourth reflector 220g to the first reflecting surface 130).

[0024] Figure 5 is a partial perspective view of a laser radar module according to another embodiment of the present invention. Referring to Figure 5, the laser radar module of this embodiment is similar to the laser radar module of Figure 3, and the main differences between the two are as follows. In the laser radar module of this embodiment, the diffuser 160 is disposed on the optical path of the laser beam 112 and is located between the second reflector 220i near the first reflective surface 130 and the first reflective surface 130. In this embodiment, the diffuser 160 is disposed near the first reflective surface 130; however, as shown in Figure 6, in another embodiment, the diffuser 160 may also be disposed near the second reflector 220i.

[0025] In summary, in the laser radar module of the embodiments of the present invention, a first reflecting surface is disposed on a first side of a rotatable support and is used to reflect a laser beam to the outside world, and a second reflecting surface is disposed on a second side of the rotatable support and is used to reflect a laser beam reflected by an external object. The rotatable support is adapted to rotate, thereby causing the first and second reflecting surfaces to rotate, so that the laser beam reflected by the first reflecting surface scans the outside world in different directions, and the second reflecting surface receives laser beams from different directions from the outside world. With this configuration, some components (i.e., the rotatable support) in the laser radar module can rotate, and during the rotation, the optical path of the laser beam emitted to the outside world and the optical path of the laser beam received from the outside world will not be reversed. Therefore, the laser radar module of the embodiments of the present invention can have the advantages of lower power consumption, higher accuracy, and lower cost. Furthermore, in the laser radar module of the embodiments of the present invention, since these reflectors are used to sequentially reflect the laser beam emitted by the laser transmitter to the first reflective surface, the laser transmitter and the photosensitive sensor can be located on the same side of the rotatable support. In this way, a simple circuit connection method can be used to simultaneously power the laser transmitter and the photosensitive sensor without the problem that the circuit needs to cross the rotatable support and make it difficult to power supply. [Simplified Explanation of the Diagram]

[0011] Figure 1A is a perspective view of a laser radar module according to an embodiment of the present invention. Figure 1B is a side view of the laser radar module of Figure 1A. Figure 1C is a partial perspective view of the laser radar module of Figure 1A from another perspective. Figure 2A shows the diffuser in Figures 1A and 1B dispersing the laser beam into a surface light source. Figure 2B shows the diffuser in Figures 1A and 1B dispersing the laser beam into a linear light source. Figure 3 is a partial perspective view of a laser radar module according to another embodiment of the present invention. Figure 4 is a partial perspective view of a laser radar module according to yet another embodiment of the present invention. Figure 5 is a partial perspective view of a laser radar module according to yet another embodiment of the present invention. Figure 6 is a partial perspective view of a laser radar module according to yet another embodiment of the present invention.

Claims

1. A laser radar module, comprising: A laser emitter used to emit a laser beam; A rotatable support having a first side and a second side opposite to each other; A first reflective surface is disposed on the first side of the rotatable support, positioned in the path of the laser beam, and used to reflect the laser beam to the outside world; a second reflective surface is disposed on the second side of the rotatable support, positioned in the path of the laser beam reflected by an object in the outside world, and used to reflect the laser beam reflected by the object; a photosensor is disposed in the path of the laser beam reflected by the second reflective surface, and used to sense the laser beam; and a plurality of reflectors are used to sequentially reflect the laser beam emitted by the laser emitter to the first reflective surface, wherein the laser emitter and the photosensor are located on the same side of the rotatable support, wherein the rotatable support is adapted to rotate to drive the first reflective surface and the second reflective surface to rotate, so that the laser beam reflected by the first reflective surface scans the outside world in different directions, and the second reflective surface receives the laser beam from the outside world from different directions. The laser emitter emits a laser beam in a horizontal direction away from the photosensor. A first reflector among the reflectors reflects the laser beam from the laser emitter in a vertical direction to the first side. A second reflector and a third reflector among the reflectors sequentially reflect the laser beam from the first reflector to the first reflective surface.

2. The laser radar module as claimed in claim 1, wherein the laser transmitter and the photosensitive sensor are disposed on the same circuit board, the laser transmitter emits the laser beam toward the first side, and the reflectors disposed on the first side sequentially reflect the laser beam toward the first reflective surface.

3. The laser radar module as claimed in claim 1, wherein the reflectors include a first reflector and a second reflector disposed on the second side, and a third reflector and a fourth reflector disposed on the first side, the laser emitter and the photosensor are disposed on the same circuit board, and the laser beam emitted by the laser emitter is sequentially directed toward the first side toward the first reflector, reflected horizontally by the first reflector to the second reflector, reflected by the second reflector to the third reflector, reflected by the third reflector to the fourth reflector, and reflected by the fourth reflector to the first reflective surface.

4. The laser radar module as claimed in claim 1, comprising a diffuser disposed in the path of the laser beam, located between the laser emitter and a first reflector closest to the laser emitter among the reflectors, or located between a second reflector close to the first reflective surface among the reflectors and the first reflective surface, and for dispersing the laser beam into a surface light source or a linear light source.

5. The laser radar module as described in claim 1, comprising: Multiple magnets are arranged around the rotatable support; A substrate having an opening for accommodating one end of the rotatable support and the magnets; and a plurality of coils disposed at the edge of the opening, wherein the coils are adapted to be energized to generate a magnetic force on the magnets, thereby causing the rotatable support to rotate.

6. The laser radar module as claimed in claim 6, wherein the first reflective surface and the second reflective surface are tilted relative to the substrate in two opposite directions at angles greater than 35 degrees and less than 55 degrees.

7. The laser radar module as described in claim 1, comprising: A first optical element is disposed in the path of the laser beam and located between the laser emitter and one of the reflectors closest to the laser emitter; and a second optical element is disposed in the path of the laser beam and located between the second reflective surface and the photosensor.

8. The laser radar module as claimed in claim 1, wherein the angle between the first reflective surface and the second reflective surface is greater than 0 degrees and less than 180 degrees.

9. The laser radar module as claimed in claim 9, wherein the angle between the first reflective surface and the second reflective surface is greater than 70 degrees and less than 110 degrees.

10. The laser radar module of claim 1, comprising a base, wherein the light sensor and the laser transmitter are both disposed on the base, the light sensor is located between the base and the second reflective surface, and the second reflective surface is located between the light sensor and the first reflective surface.

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