TWI894021B - Optical distance measuring device - Google Patents

Abstract

An optical distance measuring device is installed on a top of a vehicle running on a road. The optical distance measuring device includes an array light source. The array light source has a field of view in a direction perpendicular to the road surface, and includes a plurality of light sources which includes a plurality of near-measuring light sources and a plurality of far-measuring light sources. The field of view includes the first field of view and the second field of view, the first field of view is an angle range in which a reference optical axis of the optical distance measuring device rotates toward the road surface greater than or equal to 6.5 degrees, and the first field of view is provided only by the near-measuring light sources of the light sources in the array light source. Such that, the present invention can prevent ghosting and improve the comfort and safety of autonomous vehicles.

Description

Optical ranging device

The present invention relates to an optical ranging device, and in particular to an optical ranging device for use in vehicles.

A LiDAR (Light Detection and Ranging) system uses optical ranging technology. It measures distance and three-dimensional objects by emitting a light beam and measuring the time of flight (TOF) between the emission and the return of the reflected light. This technology accurately creates three-dimensional images of the environment or objects and is widely used in vehicles. For example, LiDAR is used in autonomous vehicles to perceive their environment. Generally speaking, to ensure sufficient reaction time to unexpected situations while driving at high speeds, optical ranging devices are often required to be able to observe objects approximately 200 to 300 meters away (or even further). LiDAR systems are also being developed with this in mind to enhance their range-finding capabilities.

FIG1 is a schematic diagram of an optical ranging device 100. As shown in FIG1 , optical ranging device 100 includes a transmitting module 110 and a detecting module 120. Transmitting module 110 may be an array of light sources, such as a plurality of light sources 110A, 110B, 110C, and 110D arranged in an array. Detecting module 120 may be an array of detectors corresponding to the light sources, such as a plurality of detectors 120A, 120B, 120C, and 120D arranged in an array. Typically, each detector corresponds to a light source to form a detection channel. For example, the detection light LA emitted by the light source 110A is collimated and shaped by the first lens group 130, and then emitted from the optical ranging device 100 through the rotating mirror 140. The detection light LA is partially scattered by the object 2, forming an echo light RA. After returning to the optical ranging device 100, the echo light RA is filtered and shaped by the second lens group (not shown) before being received by the detector 120A. The optical ranging device 100 can then use the flight time of the detection light LA and the echo light RA to calculate the distance between the object 2 and the optical ranging device 100. Since the optical ranging device 100 in FIG1 utilizes the rotation of the rotating mirror 140 to scan the detection light LA across the field of view (FOV), it is also called a scanning ranging device.

However, due to the need for system miniaturization, the layout space for the array-like arrangement of light sources 110A, 110B, 110C, 110D and detectors 120A, 120B, 120C, 120D becomes very limited. Therefore, isolating the signals between the light sources is crucial; otherwise, cross-talk can easily occur between detection channels. For example, if one detection channel receives an echo signal from another detection channel's field of view, the echo signal will appear in the detection results (e.g., a point cloud image) at the original object's location. This phenomenon is known as "ghosting."

More specifically, as shown in the simplified schematic diagram of the optical ranging device 100 in Figure 2, when light emitted by light source 110C scans the road surface 4, the light is easily reflected, diffused, and/or scattered by the road surface 4, and then reflected back to the detection module 120 by an object 2 near the road surface 4 (e.g., a pyramid or construction sign). Because the light has been reflected multiple times at different angles, the return light may be received by a non-intended detector 120D. As a result, the optical ranging device 100 will determine that there is an object in the detection channel formed by light source 110D and detector 120D, resulting in an erroneous obstacle signal, which is the aforementioned ghost image. For another example, when a vehicle is driving on a city road, the road conditions are relatively complex and changeable. If a highly reflective object suddenly appears at a close distance (for example, the license plate or signboard of a vehicle that quickly cuts into the lane at the intersection ahead) or the diffuse reflection of light produced by 4 pairs of lights on the road surface, this echoed light can easily be misjudged and cause ghosts (noise) in the point cloud image. In the context of autonomous driving, close-range noise will cause the vehicle to stop frequently, causing discomfort to passengers and not conducive to the system's determination of real objects on the road ahead, which is harmful to road safety.

Chinese Patent No. CN118235061A (hereinafter referred to as CN061) discloses a ranging LiDAR system that combines two different ranging modules: a scanning LiDAR module and a non-scanning LiDAR module. CN061 uses these two modules for ranging at different viewing angles. For example, the non-scanning LiDAR module can detect objects approximately 5 meters from the vehicle, while the scanning LiDAR module can sense objects 200 meters away. However, for the vehicle control system, this combined use imposes a computational burden. This is because each ranging module has its own coordinate system, and the vehicle also has a coordinate system for driving direction. Therefore, the vehicle control system needs to calibrate, calibrate, convert, and combine these various coordinate systems to integrate road condition information for driver behavior assessment. In other words, the CN061's dual-module ranging method imposes a computational burden on the vehicle control system and increases the possibility of misjudgment. Furthermore, the CN061 uses a non-scanning ranging module to determine the presence of objects on the road at close range, which still does not solve the ghosting problem previously mentioned with scanning LiDAR modules.

The main purpose of the present invention is to provide an optical ranging device that can prevent ghosting and improve the comfort and safety of autonomous vehicles.

Another object of the present invention is to provide an optical ranging device having multiple linearly arranged light sources. Detection within a specific field of view utilizes only the near-field light source to avoid signal interference caused by high-energy light from the far-field light source being reflected/scattered by nearby high-reflectivity objects and easily misreceived by other detection channels.

Another object of the present invention is to provide an optical ranging device suitable for use in urban self-driving vehicles to avoid abnormal driving behavior caused by ghost signals caused by high-reflectivity objects at close range, while also complying with regulatory requirements.

To achieve the aforementioned objectives, the present invention provides an optical ranging device, mounted on the roof of a vehicle traveling on a road, comprising an array of light sources. The array of light sources has a field of view perpendicular to the road surface and includes a plurality of light sources, including a plurality of near-field light sources and a plurality of far-field light sources. The field of view includes a first field of view and a second field of view, wherein the first field of view is a field of view obtained by rotating a reference optical axis of the optical ranging device toward the road surface by a factor greater than or equal to 1. The first zone field of view is provided only by the near detection light sources of the light sources in the array of light sources.

In some embodiments, the first field of view is a rotation of the reference optical axis of the optical ranging device toward the road surface greater than or equal to Angle range.

In some embodiments, the light sources are arranged in the order of light source 1, light source 2, light source 3 to light source x in a direction perpendicular or non-parallel to the road surface. The light source farthest from the top of the vehicle is light source 1, and the light source closest to the top of the vehicle is light source x. The field of view of light source n among the light sources covers , wherein x is a positive integer greater than 1, n is a positive integer greater than 1 and less than or equal to x, and the light sources from No. n to No. x in the light sources are proximity light sources. Preferably, the light sources from No. 1 to No. Light source No. 1 is a telemetry light source, or a combination of a telemetry light source and a near-field light source. Preferably, light sources No. 1, No. 2, No. 3 through No. x provide multiple single line light sources for scanning the field of view. These multiple single line light sources are reflected by a rotating mirror and used to scan the field of view in a direction parallel to the road surface.

In some embodiments, the near-field light source and the far-field light source provide multiple single line light sources for scanning in the field of view. The multiple single line light sources are reflected by a rotating mirror and used to scan the field of view in a direction parallel to the road surface.

In some embodiments, the near-detection light sources and the far-detection light sources are arranged in an aligned or staggered linear array.

In some embodiments, the wavelength of the near-field light source and/or the far-field light source is 905 nm, 940 nm, or 1550 nm.

In some embodiments, the array light source includes a first light source array module and a second light source array module that are separated.

In some embodiments, the first light source array module and the second light source array module each have M1 light sources and M2 light sources, wherein the M1 light sources emit M1 and the M2 light sources emit M2 light signals, wherein the M1 light signals form S1 split light signals after passing through a split light component, and the M2 light signals form S2 split light signals after passing through the split light component, wherein S1 is greater than M2. When M1 and S2 are greater than M2, the S1 split light signal and the S2 split light signal are sequentially No. 1 detection light, No. 2 detection light, No. 3 detection light, to No. x detection light in the direction perpendicular or non-parallel to the road surface. The No. 1 detection light is farthest from the top of the vehicle, and the No. x detection light is closest to the top of the vehicle. The field of view of the No. n detection light among the multiple detection lights covers , wherein x is a positive integer greater than 1, n is a positive integer greater than 1 and less than or equal to x, and the light source that emits the nth detection light to the xth detection light among the M1 and M2 light sources is the proximity light source. Preferably, the M1 light source and the M2 light source that emits the 1st detection light to the The light source of the detection light is a range-finding light source, or a combination of a range-finding light source and a near-finding light source. Preferably, light sources No. 1, No. 2, No. 3, through No. x provide multiple single line light sources for scanning the field of view. These multiple single line light sources are reflected by a rotating mirror and used to scan the field of view in a direction parallel to the road surface.

The effectiveness of the present invention lies in that it can prevent ghost images and improve the comfort and safety of autonomous vehicles.

The following is a more detailed description of the implementation of the present invention with reference to the drawings and component symbols, so that those skilled in the art can implement the invention accordingly after studying this specification.

FIG3 illustrates one or more exemplary optical ranging devices 1 according to the present invention, mounted or included on the roof of a vehicle 3. Vehicle 3 can be any vehicle that meets the definitions of the Society of Automotive Engineers (SAE) as a non-automated vehicle, a partially automated (driver-assisted) vehicle, a conditionally automated vehicle, a highly automated vehicle, or a fully automated vehicle. For example, a partially automated vehicle can perform some driving functions without a human driver operating the steering wheel or pedals, such as lane keeping and/or lane changing, and automatic emergency braking. Alternatively, a fully automated vehicle can operate autonomously under all circumstances.

LiDAR is often a sensing device mounted on the aforementioned vehicle 3 for sensing the distance and/or position of objects ahead. In one embodiment, as shown in FIG3 , vehicle 3 may include an optical ranging device 1 mounted at the highest point of the vehicle (e.g., on the roof), which is a LiDAR system. For example, the LiDAR system mounted on the roof performs 360-degree scanning or any other angle scanning. Unless otherwise specified, scanning herein refers to the LiDAR system emitting one or more light beams in one or more directions (e.g., horizontal and/or vertical directions) to scan objects within the field of view (FOV). This article primarily addresses the signal interference issues encountered by scanning LiDARs, not scanning LiDARs. For example, flash LiDARs are not the architecture addressed in this article's solution.

Figure 4A schematically illustrates the structure of an optical ranging device 1 according to an embodiment of the present invention. Figure 4B schematically illustrates another embodiment of a transmitting module 30 according to an embodiment of the present invention. As shown in Figure 4A, the first embodiment of the present invention provides an optical ranging device 1 comprising a housing 10, a window 20, a transmitting module 30, a rotating mirror 40, a detection module 50, a first lens assembly 60, a reflective mirror 70, and a second lens assembly 80. The housing 10 and the window 20 are assembled to form a space for accommodating the aforementioned modules. The optical ranging device 1 according to an embodiment of the present invention can be, for example, a forward-facing laser radar. As shown in the figure, the window 20 faces forward (e.g., in the direction of a vehicle's travel), and detection light LA is directed outward from the window 20 for scanning detection. The emission module 30 includes an array of light sources, for example, a plurality of light sources arranged in an array. An exemplary light source array may be: For simplicity, Figure 4A shows only four light sources 31A, 31B, 31C, and 31D. In this embodiment, an array arrangement means that light sources 31A, 31B, 31C, and 31D are arranged substantially along a direction Z (also known as the vertical direction or Z-axis) perpendicular to the ground. In other words, the number "1" in the aforementioned array formula represents the light sources arranged in a row in direction Z, forming linear light sources. When light sources 31A, 31B, 31C, and 31D in Figure 4A emit a single linear light signal, they can scan an object in direction Z. It is worth noting that the aforementioned light sources 31A, 31B, 31C, and 31D can be arranged in a staggered manner (as shown in FIG4B ). Such a staggered arrangement is also considered a linear arrangement in this article because the left-right staggered distance between the light sources 31A, 31B, 31C, and 31D is negligible with respect to the speed of light. In other words, for the detection module 50, regardless of whether the position of the light source 31B is aligned with the light sources 31A, 31B, 31C, and 31D (as shown in FIG4A ) or staggered by a certain distance (as shown in FIG4B ), the light emitted by the light sources 31A, 31B, 31C, and 31D can be considered to be aligned with each other on the Z axis. For example, a linear array can be considered to be arranged in a linear array if the length of one dimension is much greater than the length of another dimension, such as greater than or equal to 3, 5, or 10 times. For example, in FIG4B , the length of the emission module 30 in the Z axis direction is greater than or equal to 3, 5, or 10 times the length of the emission module 30 in the X axis direction.

The detection module 50 includes an array of detectors (not shown), which are configured in a manner corresponding to the array of light sources, such as the arrangement of the detectors, the proximity distance, the sensing angle, etc. The configuration of the detection module 50 in this article can be arranged using any known technology and will not be further described in this article.

As shown in Figure 4A , light sources 31A, 31B, 31C, and 31D output optical signals, which are adjusted (e.g., shaped or collimated) by a first lens assembly 60 and then emitted through a rotating mirror 40 through a window 20 toward the exterior of the optical distance-measuring device 1 to form detection light LA. In this embodiment, rotating mirror 40 is connected to a driver, such as a motor, for continuous rotation. In Figure 4A , rotating mirror 40 is depicted as rotating in a horizontal plane (i.e., the plane defined by the X-axis and the Y-axis, which is substantially parallel to the ground). In Figure 4A , rotating mirror 40 also schematically rotates clockwise along axis 41, as indicated by the arrow. This causes detection light LA to scan across the XY plane, thereby detecting objects within the horizontal field of view (relative to the vertical field of view). It is understood that the LiDAR system shown in FIG4A utilizes a linear array light emitting module 30 arranged along the column direction (Z axis) to achieve vertical field of view scanning, and then utilizes a rotating mirror 40 to achieve horizontal field of view scanning through one-dimensional lateral rotation, thereby scanning the space in front of the vehicle 3. Each vertical and horizontal scanning detection of the detection light LA produces a detection result, such as a frame of a point cloud image. This frame of point cloud image can cover a total field of view of the horizontal and vertical fields of view. However, the present invention primarily focuses on the vertical field of view.

Referring to Figure 4A, the detection light LA is reflected and diffused by an object (not shown) to form an echo light RA. The echo light RA enters the optical ranging device 1 through the window 20, and is received by the detection module 50 after being acted upon (e.g., shaped or focused) by the rotating mirror 40, the reflecting mirror 70, and the second lens group 80. It can be understood that Figure 4A exemplarily depicts the detection channel formed by the light source 31B and its corresponding detector. In other words, a plurality of light sources and a plurality of detectors can correspond to form a plurality of detection channels, each detection channel can correspond to a different field of view, and the field of view of the detection channel of the embodiment of the present invention can be explained using a light source. For example, the vertical field of view of the optical ranging device 1 of the present invention is , the horizontal direction of the installation height of the optical distance measuring device 1 of the present invention is (i.e. the horizontal direction L shown in FIG3 ), the angle tilted counterclockwise upward is negative, and the angle tilted clockwise downward is positive. Assuming that the vertical angular resolution of each light source in the embodiment of the present invention is The light source 31A at the highest position in the light source array emits light which is shaped by the lens (group) and then emission, so the light beam of light source 31A corresponds to The vertical field of view; the light beam of the second highest position light source 31B in the light source array corresponds to Vertical field of view, and so on It is worth noting that regardless of whether light sources 31A, 31B, 31C, and 31D are aligned (as in Figure 4A) or staggered (as in Figure 4B), the vertical field of view of each light source in direction Z (e.g., the vertical direction or Z-axis) can meet the aforementioned requirements. Furthermore, each vertical field of view can be overlapping or non-overlapping, which allows for a slight divergence angle of the detection light LA.

In some embodiments, the number of light sources 31A, 31B, 31C, 31D and detectors forming a detection channel is not limited. Preferably, light sources 31A, 31B, 31C, 31D and a corresponding number of detectors form a detection channel. When the light sources and detectors belonging to the same detection channel are activated and operating, the detection channel is in operation, thereby enabling detection of an object.

In some embodiments, the emission module 30 may be a vertical cavity surface emitting laser (VCSEL) or an edge emitting laser (EEL). Applying a driving current to the emission module 30 drives the laser to emit the detection light LA.

In some embodiments, the detection module 50 may be an avalanche photodiode (APD) or a silicon photomultiplier (SiPM). By applying a bias voltage (V _bias ) to the detector of the APD or SiPM, the detection module 50 is activated to detect the echo light RA.

It should be noted that the rotating mirror 40, the first lens assembly 60, the reflective mirror 70, and the second lens assembly 80 of the first embodiment of the present invention can all be selected from known optical components and will not be described in detail here. In addition, appropriate optical lens assemblies can be added to the optical path as needed and are not limited to this embodiment. The optical path depicted in FIG4A is merely an example and is not actually limited to the optical path structure of the optical ranging device 1 of the present invention.

Returning to Figure 3, it shows a schematic diagram of an optical ranging device 1 according to an embodiment of the present invention mounted on the roof of a vehicle 3. This embodiment of the present invention provides a scanning LiDAR system with an array light source. This array light source offers angular selectivity to address the aforementioned ghosting issue. As shown in Figure 3, the vertical total field of view 90 of the optical ranging device 1 can be substantially divided into a first field of view (low-angle field of view) 91 and a second field of view (forward detection field of view) 92. The first field of view (low-angle field of view) 91 is solely provided by the near-field detection light source. As countries around the world increasingly prioritize the use of autonomous vehicles, numerous regulations related to autonomous driving have recently been announced. The present invention also complies with the regulations/rules of the mainstream autonomous vehicle market to produce the optical ranging device 1 of the present invention, thereby simultaneously meeting regulatory requirements and resolving technical signal interference issues.

Specifically, the optical ranging device 1 of the present embodiment is mounted on the roof of a vehicle 3 traveling on a road 4. According to vehicle database statistics, the average height of vehicles ranges from 1.2 to 1.98 meters. The height H of vehicle 3 in the present embodiment is calculated based on the average value of 1.58 meters. Furthermore, based on US testing of Automatic Emergency Braking (AEB) systems, the time to collision (TTC) for vehicle 3 is set at 5 seconds. This means that while driving, vehicle 3 must not collide with the vehicle in front (including objects, pedestrians, etc.) within 5 seconds. The present embodiment calculates the minimum forward detection distance D of the optical ranging device 1 according to the aforementioned collision time. That is, when the vehicle 3 is moving at a constant speed, the optical ranging device 1 can continuously sense objects within the minimum forward detection distance D, preventing the vehicle 3 from colliding. According to the distance formula for constant velocity motion: ; As for the self-driving system, it is relatively difficult to drive in the city compared to the highway. Its complexity and uncertainty are much higher than that on the highway. For example, there is no separation between people and vehicles, unclear lanes, a variety of traffic lights, accidents ahead, illegal parking and blocking the road, etc. Therefore, the embodiment of the present invention is mainly set up for self-driving in the city, that is, the speed is not high (for example, 10km/hr), but the objects ahead must be monitored at all times. In summary, the minimum forward detection distance of the embodiment of the present invention is Calculated , and then use trigonometric functions to deduce the tilt angle , that is, from FIG4A, from the horizontal plane of the optical distance measuring device 1 of the present invention (i.e., the horizontal plane drawn in FIG4A The reference optical axis L) rotates toward the road surface 4 by an angle greater than or equal to (The direction of rotation is already explained here, so the positive and negative signs are not marked to avoid confusion) The range is the first field of view 91 (i.e., the low-angle field of view), and the array light source includes a plurality of near-field light sources and a plurality of far-field light sources. The first field of view 91 is provided solely by the near-field light sources in the array light source. This prevents ghosting and improves the comfort and safety of the autonomous vehicle 3.

FIG5 shows the relationship between the emitting module 30 and the aforementioned field of view of the first embodiment of the present invention. As shown in FIG5 , the emitting module 30 has light sources 31A, 31B, 31C, and 31D. The field of view of each light source 31A, 31B, 31C, and 31D is , the total viewing angle on the Z axis is As shown in FIG5 , the center of the light source 31B corresponds to The reference optical axis L, so from the perspective of field of view, the total field of view of the lower half of the field of view of light source 31B and the field of view of light source 31C will cover The field of view (i.e. ), and according to the calculation above, greater than or equal to Field of view (in The reference optical axis L rotates clockwise) is only responsible for the proximity light source, so the light source 31D must be a proximity light source, and its responsible field of view range (i.e. ) is equivalent to the first area of the field of view 91 shown in FIG3 ; and the light sources 31A, 31B, and 31C can be telescopic light sources, or a combination of a telescopic light source and a near-field light source, and the field of view range (i.e. ) is equivalent to the second field of view 92 shown in FIG3. In this embodiment, the angle Range (in The angle of the reference optical axis L rotating clockwise) is covered by the light source 31D (i.e., the proximity light source), but the field of view of this angle is not the focus of the present invention. It is worth noting that the field of view referred to herein refers to the angle covered by the detection light LA passing through the optical device (such as the first lens group 60, the rotating mirror 40, etc., but not limited to this) and finally emitted through the window 20. For the sake of simplicity, Figure 5 only depicts the light source and the first lens group 60. In another embodiment, other proximity light sources can be included to cover a larger low-angle field of view, for example, more proximity light sources can be arranged below the light source 31D to cover Field of view (in Similarly, other telescopic light sources may be included to cover a larger forward detection field of view, for example, more telescopic light sources may be arranged above the light source 31D to cover the forward detection field of view. Field of view (in (angle of counterclockwise rotation of the reference optical axis L).

In this embodiment, the maximum ranging range of the near-field light source is less than approximately 100m, such as 90m, 70m, 50m, 25m, 10m, 5m, etc.; the minimum ranging range of the far-field light source is greater than approximately 200m, such as 230m, 250m, 260m, 300m, 350m, 400m, etc., and the difference in ranging can be mainly controlled by the current applied to the aforementioned light-emitting chip. In one embodiment, chips with different luminous powers can be used to distinguish between near-field and far-field light sources. Taking a vertical cavity surface emitting laser (VCSEL) light source as an example, the average optical power per aperture of the near-field light source (under nanosecond (ns) pulse conditions) is less than 10mW, such as 0.1mW, 0.5mW, 1mW, 5mW, etc., while the average optical power per aperture of the far-field light source (under nanosecond (ns) pulse conditions) is greater than 10mW, such as 15mW, 20mW, 30mW, 50mW, 100mW, etc. In another embodiment, taking a vertical cavity surface emitting laser array (VCSEL) array light source as an example, the peak power of the near-field light source (under 10 kHz/10 nanosecond (ns) short pulse test conditions) is less than 100 W, such as 8 W, 10 W, 20 mW, 50 W, etc., while the peak power of the far-field light source (under 10 kHz/10 nanosecond (ns) short pulse test conditions) is greater than 100 W, such as 110 W, 120 W, 150 W, 200 W, 1000 W, etc. As previously mentioned, since the low-angle field of view (i.e., the first zone field of view 91) is detected by the proximity light source, the detection light LA emitted toward the ground is a low-energy beam. This can reduce the probability of the echo reflected by highly reflective objects being mistakenly received by the detectors in other detection channels, thereby reducing the ghosting problem caused by the aforementioned misreceived signals.

In this embodiment, the emission module 30 further includes a control module (not shown), such as a Field Programmable Gate Array (FPGA), a Microcontroller Unit (MCU), a System on Chip (SoC), or an Application-Specific Integrated Circuit (ASIC), which can be used to control the light sources 31A, 31B, 31C, and 31D to emit light. This article proposes a solution to the interference caused by linear light sources. Therefore, the control module essentially controls the aforementioned light sources 31A, 31B, 31C, and 31D to emit light "simultaneously." For example, at a first time point, the control module emits a first pulse, causing all four light sources (i.e., all light sources) to emit light simultaneously, performing a first scan. Then, at a second time point, the control module emits a second pulse, causing all four light sources (i.e., all light sources) to emit light simultaneously, performing a second scan. Multiple scans of objects in front of the vehicle are performed in this manner. As those skilled in the art will understand, the control module driving light sources 31A, 31B, 31C, and 31D to emit light in a timed sequence is also considered to be "simultaneous" illumination because the interval between illumination sequences is typically quite short, such as a few microseconds or even less, and is negligible. For example, at a first time point, the control module emits a first pulse causing light sources 31A and 31C to emit light simultaneously, and at a second time point, emits a second pulse causing light sources 31B and 31D to emit light. Since the interval between the first and second time points is negligible, the first scan is still considered to be performed by light signals emitted "simultaneously" by light sources 31A, 31B, 31C, and 31D. Subsequently, the above steps are repeated to perform the second and third scans. That is, the near-field light source responsible for the low-angle field of view and the light source outside the low-angle field of view (such as the far-field light source) of the embodiment of the present invention emit a single linear light and repeat it multiple times to perform the scanning operation.

In one embodiment, the light source of each emission module 30 is activated by a drive signal provided by a control module. The drive signal may be generated by a drive circuit within the control module. For example, the drive signal may include one or more pulse signals, such as a periodic pulse signal. The emission signal of the light source may also include one or more pulsed light signals. Generally, the drive signal may include the following exemplary characteristics: wavelength, pulse width, number of pulses, pulse peak value, and pulse interval.

In summary, the light sources in the transmitting module 30 of the optical ranging device 1 of the first embodiment of the present invention can be arranged as follows: the light sources are arranged in the direction substantially perpendicular or non-parallel to the road surface 4 in the order of light source No. 1 (such as light source 31A), light source No. 2 (such as light source 31B), light source No. 3 (such as light source 31C) to light source No. x (not shown in the figure, but it should be understood as the light source arranged below light source 31D), and the light source No. 1 (such as light source 31A) is farthest from the top of the vehicle 3, and the light source No. x is closest to the top of the vehicle 3 (according to the schematic diagram drawn in Figure 5, x=4). The field of view of light source No. n among these light sources covers The angle between the nth light source and the xth light source is the proximity light source. That is to say, in Figure 5, the field of view of the 4th light source covers The angle of , therefore, the fourth light source is a near light source (in this embodiment, ); In addition, light sources No. 1 to No. 3 may be telescopic light sources, or a combination of telescopic light sources and near-field light sources. In another embodiment, In the case of seven light sources, light sources No. 4 to No. 7 are near-field light sources; similarly, light sources No. 1 to No. 3 can be far-field light sources, or a combination of far-field and near-field light sources.

Figure 6A illustrates an optical ranging device 1 according to a second embodiment of the present invention, primarily illustrating the relationship between the transmitting module 30A and the aforementioned field of view. Figure 6B is an enlarged schematic diagram of region A of Figure 6A. In this embodiment, the transmitting module 30 includes a first light source array module 32 and a second light source array module 33 that are physically separated. Each module includes four light sources 321A, 321B, 321C, and 321D, and 331A, 331B, 331C, and 331D arranged in a linear array. The first and second light source array modules 32 and 33 are considered separated from each other, both in terms of their optical paths and physical circuit layouts (e.g., whether they are disposed on different PCBs). The first lens assembly 60 includes a first collimating lens 61 corresponding to the first light source array module 32 , a second collimating lens 62 corresponding to the second light source array module 33 , a reflecting mirror 63 , and a beam splitter assembly 64 . Specifically, the four light beams emitted by the first light source array module 32 are conditioned (e.g., shaped or collimated) by the first collimating lens 61 before being output to the spectrometer assembly 64. Furthermore, the four light beams emitted by the second light source array module 33 are conditioned (e.g., shaped or collimated) by the second collimating lens 62 before being output to the spectrometer assembly 64 via the reflector 63. The spectrometer assembly 64 then splits the eight light beams emitted by the first and second light source array modules 32 and 33 into ninety-six detection light beams LA1-LA96. In short, the optical signal emitted by one light source is split into twelve light signals by the spectrometer assembly 64. For example, LA1-LA12 are emitted by light source 321A. Similarly, LA13-LA24 are emitted by light source 321B. In this embodiment, the light splitting component 64 can be a lens assembly, such as a diffractive optical element (DOE) or an optical waveguide element, or the light splitting component 64 can be an optical fiber, such as a fiber optic splitter. As mentioned above, the detection lights LA1-LA96 are emitted substantially "simultaneously."

In this embodiment, the transmitting module 30A can cover the vertical field of view The vertical angular resolution is , that is, the detection light LA1 corresponds to Vertical field of view, detection light LA2 corresponds to Vertical field of view, and so on. Based on this, as shown in FIG6A and FIG6B, this embodiment can calculate the detection light LA74 corresponding to Vertical field of view (in The reference optical axis L is rotated clockwise), and according to the above, it is greater than or equal to 6.5 Field of view (in The angle of reference optical axis L rotating clockwise) is only responsible for the proximity light source. Since the detection light LA74 is emitted by the light source 331B on the second light source array module 33 and is a beam generated after the light is split, the light source 331B should be the proximity light source. Similarly, the light source 331A on the second light source array module 33 should also be the proximity light source (because the light source 331A is responsible for a larger angle of view). In short, the light sources 331A and 331B on the second light source array module 33 are proximity light sources, and Vertical field of view (in The reference optical axis L is rotated clockwise by an angle) and is defined as the aforementioned first field of view 91, which is only responsible for the proximity light source. The first field of view 91 corresponds to the detection range of the detection lights LA74 to LA96. On the other hand, the light sources 321A, 321B, 321C, and 321D of the first light source array module 32 or the other two light sources 331C and 331D of the second light source array module 33 can be telemetry light sources or a combination of a telemetry light source and a proximity light source, which are responsible for the second field of view 92, corresponding to the detection range of the detection lights LA74 to LA96 of this embodiment. The vertical field of view is equivalent to the second zone field of view 92 shown in FIG3.

Those skilled in the art will appreciate that the detection light emitted by the emission module 30 of the second embodiment of the present invention can be combined with other optical elements of the first embodiment to perform detection scanning of the horizontal field of view and the vertical field of view, which will not be elaborated herein.

In summary, the light sources of the emission module 30 of the second embodiment of the present invention can be arranged as follows: the first light source array module 32 and the second light source array module 33 each have M1 light sources and M2 light sources. The M1 light sources emit M1 light signals, and the M2 light sources emit M2 light signals. The M1 light signals pass through the light splitting component 64 to form S1 split light signals, and the M2 light signals pass through the light splitting component 64 to form S2 split light signals, where S1 is greater than M1, and S2 is greater than M2. Referring to FIG. 6A , , The S1 and S2 spectroscopic signals are sequentially No. 1 detection light, No. 2 detection light, No. 3 detection light to No. x detection light in the direction perpendicular or non-parallel to the road surface. The No. 1 detection light is the farthest from the top of the vehicle, and the No. x detection light is the closest to the top of the vehicle. The field of view of the No. n detection light among the multiple detection lights covers According to Figures 6A and 6B, , , so light source 331A and light source 331B are proximity light sources, which emit detection light No. 74 to detection light No. 96. Light sources 321A, 321B, 321C, 321D and light sources 331C, 331D can be telemetry light sources or a combination of telemetry light sources and proximity light sources, which emit detection light No. 1 to detection light No. 73. In another embodiment, , so there is only one light source (such as light source 331A in FIG6A ) as a proximity light source.

In another embodiment, a car manufacturer may require that the optical ranging device installed on a vehicle be able to detect low objects (such as squatting pedestrians, pets, etc.) within ten meters. To meet this requirement, this embodiment assumes that the optical ranging device 1 of the present invention is irradiated downward from the top of the vehicle 3 to the road surface 4 eight meters in front of the vehicle 3. When the height H of the vehicle 3 is 1.58 meters, according to the definition of the sine of the trigonometric function, it can be calculated that the detection angle of the optical ranging device 1 of the present invention toward the road surface 4 will be greater than or equal to That is to say, in this embodiment, greater than or equal to Field of view (in The reference optical axis L (the angle rotated clockwise) is only responsible for the near-light source, which can solve the aforementioned ghosting problem and at the same time meet the need for detecting low objects at a close distance.

Preferably, the center wavelength of the optical signal emitted by the aforementioned proximity light source or distance light source can be 905nm, 940nm or 1550nm; the half-height width of the optical signal can be 0.1~10nm; the temperature variation coefficient of the wavelength of the optical signal is less than 0.1nm/ , for example 0.07nm/ , 0.045 nm/ Wait; the light signal spot is roughly circular.

Preferably, the second zone field of view 92 is provided by a far light source and/or a near light source. Preferably, the vertical field of view of the embodiment of the present invention is The maximum positive angle of the reference optical axis in the clockwise direction is 、 、 etc.; preferably, the vertical field of view of the embodiment of the present invention is The maximum counterclockwise rotation angle of the reference optical axis can be 、 、 etc.

Therefore, the embodiment of the present invention divides the vertical field of view of a single scanning optical ranging device into a low-angle field of view and a forward detection field of view. The low-angle field of view is only responsible for the proximity light source. By using the low power of the proximity light source, the problem of false echo reception can be greatly reduced. In addition, the embodiment of the present invention further complies with the requirements of autonomous driving regulations, and uses the proximity light source to detect angles greater than or equal to the vehicle's height. Field of view (in From a hardware design perspective, the optical ranging system is designed to comply with autonomous driving regulations while also preventing autonomous vehicles from misjudging signals and causing abnormal driving behavior (such as frequent braking or dangerous emergency braking).

In addition, some publicly available technologies utilize software (or operating methods) to filter out the aforementioned erroneously received interference signals. For example, this involves repeatedly performing the "transmit signal - receive echo" optical ranging step on the same detection channel and comparing the multiple TOF results. If the TOF results are similar, the detection result of that detection channel is considered valid; otherwise, the detection result of that detection channel is discarded. However, as mentioned above, under complex urban road conditions, performing multiple detections and calculation comparisons cannot immediately detect objects ahead, and also places a burden on the vehicle control system.

On the other hand, there is a disclosed technology that proposes a solution for the blind spot of the ranging device. In other words, the solution is to reinforce the area outside the field of view of the ranging device. In contrast, the embodiment of the present invention plans the characteristics of the light source within the field of view of the ranging device, so the two problems to be solved are different concepts. Taking a step back, the blind spot solution mentioned in the disclosed technology mostly adds additional detectors to detect blind spots. Such a solution will also cause the computational burden of the vehicle control system, because different detectors are placed in different positions, have different detection angles, and different signal types. The data obtained by these different detectors must undergo coordinate/signal conversion, calibration, alignment and other operations before they can be combined with each other, and in particular, they must be combined with the data obtained by the different detectors. Consider the issue of interference from each detector's own signal. For example, consider the highly reflective obstacle (such as a construction pyramid) mentioned in the embodiments of the present invention. If one detector determines that the pyramid is at distance A, while another detector, due to signal interference, mistakenly determines that it is at distance B, the vehicle control system must divert resources to determine which detector is correct. This situation poses a potential concern for driver safety.

The above description is only used to explain the preferred embodiments of the present invention and is not intended to limit the present invention in any form. Therefore, any modifications or changes to the present invention made under the same spirit of the invention should still be included in the scope of protection intended by the present invention.

1: Optical ranging device 2: Object 3: Vehicle 4: Road surface 10: Housing 20: Window 30, 30A: Transmitter module 31A, 31B, 31C, 31D: Light source 32: First light source array module 321A, 321B, 321C, 321D: Light source 33: Second light source array module 331A, 331B, 331C, 331D: Light source 40: Rotating mirror 41: Rotating axis 50: Detection module 60: First lens assembly 61: First collimating lens 62: Second collimating lens 63: Reflector 64: Spectral assembly 70: Reflector 80: Second lens group 90: Vertical total field of view 91: First zone field of view 92: Second zone field of view 100: Optical ranging device 110: Transmitter modules 110A, 110B, 110C, 110D: Light source 120: Detection modules 120A, 120B, 120C, 120D: Detector 130: First lens group 140: Rotating mirror D: Front probe distance L: Reference optical axis LA, LA1-LA96: Detection light RA: Echo light : Angle

Figure 1 is a schematic diagram of an optical ranging device. Figure 2 is a simplified schematic diagram of an optical ranging device. Figure 3 is a diagram of one or more exemplary optical ranging devices according to the present invention, mounted on or included on a vehicle roof. Figure 4A is a schematic diagram of the structure of an optical ranging device according to an embodiment of the present invention. Figure 4B is a schematic diagram of another embodiment of a transmitting module according to an embodiment of the present invention. Figure 5 is a diagram illustrating the relationship between the transmitting module according to the first embodiment of the present invention and the aforementioned field of view. Figure 6A is a diagram illustrating the transmitting module according to the second embodiment of the present invention, primarily illustrating the relationship between the transmitting module and the aforementioned field of view. Figure 6B is an enlarged schematic diagram of area A of Figure 6A.

1: Optical ranging device

3: Vehicles

4: Road surface

90: Field of view

91: First Zone Field of View

92: Second Zone Field of View

θ: Indentation Angle

L: Reference optical axis

Claims (10)

An optical ranging device is installed on the top of a vehicle traveling on a road. The optical ranging device includes: an array light source having a field of view perpendicular to the road surface and comprising a plurality of light sources, the light sources including a plurality of near-field light sources and a plurality of far-field light sources; wherein the field of view includes a first field of view and a second field of view, the first field of view being a reference optical axis of the optical ranging device rotated toward the road surface by an angle greater than or equal to The first zone field of view is provided only by the near-detection light sources of the light sources in the array of light sources; wherein the near-detection light sources and the far-detection light sources provide multiple single line light sources for scanning in the field of view, and the multiple single line light sources are reflected by a rotating mirror and used to scan the field of view in a direction parallel to the road surface. The optical distance measuring device as claimed in claim 1, wherein the first field of view is the reference optical axis of the optical distance measuring device rotated toward the road surface by a distance greater than or equal to Angle range. The optical ranging device as described in claim 1, wherein the near-field light sources and the far-field light sources are arranged in an aligned or staggered linear array. An optical ranging device as described in claim 1, wherein the wavelength of the near-field light sources and/or the far-field light sources is 905nm, 940nm or 1550nm. The optical ranging device as claimed in claim 1, wherein the light sources are arranged in order of light source No. 1, light source No. 2, light source No. 3 to light source No. x in a direction perpendicular or non-parallel to the road surface, the light source No. 1 being the farthest from the top of the vehicle, the light source No. x being the closest to the top of the vehicle, and the field of view of the light source No. n among the light sources covering , where x is a positive integer greater than 1, n is a positive integer greater than 1 and less than or equal to x, and the light sources No. n to No. x among the light sources are proximity light sources. The optical distance measuring device as claimed in claim 5, wherein the light sources No. 1 to No. The light source is a telemetering light source, or a combination of a telemetering light source and a near metering light source. The optical ranging device as described in claim 1, wherein the array light source includes a first light source array module and a second light source array module that are separated. The optical ranging device as described in claim 7, wherein the first light source array module and the second light source array module each have M1 light sources and M2 light sources, the M1 light sources emit M1 light signals, the M2 light sources emit M2 light signals, the M1 light signals form S1 split light signals after passing through a splitting component, and the M2 light signals form S2 split light signals after passing through the splitting component. , where S1 is greater than M1, S2 is greater than M2, and the S1 split light signal and the S2 split light signal are sequentially No. 1 detection light, No. 2 detection light, No. 3 detection light to No. x detection light in a direction perpendicular or non-parallel to the road surface. The No. 1 detection light is farthest from the top of the vehicle, and the No. x detection light is closest to the top of the vehicle. The field of view of the No. n detection light among the multiple detection lights covers wherein x is a positive integer greater than 1, n is a positive integer greater than 1 and less than or equal to x, and the light source that emits the nth detection light to the xth detection light among the M1 light sources and the M2 light sources is the proximity detection light source. The optical distance measuring device as claimed in claim 8, wherein the M1 light sources and the M2 light sources emit the first detection light to the The light source of the signal detection light is a far-finding light source, or a combination of a far-finding light source and a near-finding light source. An optical ranging device is installed on the top of a vehicle traveling on a road. The optical ranging device includes: an array light source having a field of view perpendicular to the road surface and comprising a plurality of light sources, the light sources including a plurality of near-field light sources and a plurality of far-field light sources; wherein the field of view includes a first field of view and a second field of view, the first field of view being a reference optical axis of the optical ranging device rotated toward the road surface by an angle greater than or equal to The first zone field of view is provided only by the near-field light sources of the light sources in the array light source; wherein the array light source includes a first light source array module and a second light source array module, each of the first light source array module and the second light source array module has M1 light sources and M2 light sources, the M1 light sources emit M1 light signals, the M2 light sources emit M2 light signals, and the M1 light signals form S1 split light signals after passing through a splitting component. , the M2 optical signals form S2 split light signals after passing through the split light assembly, wherein S1 is greater than M1, S2 is greater than M2, and the S1 split light signal and the S2 split light signal are sequentially No. 1 detection light, No. 2 detection light, No. 3 detection light to No. x detection light in a direction perpendicular or non-parallel to the road surface. The No. 1 detection light is farthest from the top of the vehicle, and the No. x detection light is closest to the top of the vehicle. The field of view of the No. n detection light among the multiple detection lights covers wherein x is a positive integer greater than 1, n is a positive integer greater than 1 and less than or equal to x, and the light source that emits the nth detection light to the xth detection light among the M1 light sources and the M2 light sources is the proximity detection light source.