Laser light source, light emitting unit and laser radar

Abstract

Embodiments of the present invention provide a laser light source, a light emitting unit, and a laser radar. The light emitting unit for the laser radar comprises a first light emitting area and a second light emitting area. The first and second light emitting areas are of different sizes and form a common light channel, respectively, for detecting targets at different distances. Embodiments of the present invention reduce the transmission power of the light emitting unit.

Description

Technical Field

[0001] The present invention relates to the field of laser radar, and in particular to a laser light source, a light emitting unit and a laser radar. Background Art

[0002] Light Detection and Ranging (LIDAR) plays an important role in autonomous driving, including roadside detection, obstacle recognition, and real-time localization and mapping (SLAM).

[0003] Specifically, a LIDAR system consists of a laser transmitting system and a light receiving system. The laser transmitting system includes a light emitting unit that generates a light pulse. This light pulse is incident on a target, reflects, and produces an echo beam. This echo beam is ultimately received by the light receiving system. The receiving system accurately measures the propagation time of the incident light pulse from emission to reflection. Because light pulses travel at the known speed of light, the propagation time can be converted into a distance measurement.

[0004] LiDAR can accurately measure a target's position (distance and angle), motion (speed, vibration, and posture), and shape, enabling it to detect, identify, distinguish, and track targets. Due to its advantages of fast measurement speed, high accuracy, and long range, LiDAR is widely used in unmanned vehicles.

[0005] However, the light emitting unit of the laser radar in the disclosed technology has the problem of high emission power. Summary of the Invention

[0006] The problem solved by the present invention is to provide a laser light source, a light emitting unit and a laser radar to reduce the light emission power.

[0007] The technical solution of the present invention provides a laser light source, which includes: at least two light-emitting areas, and the relative sizes of the at least two light-emitting areas are different.

[0008] Optionally, the at least two light-emitting areas share an enable signal and are driven to emit light at the same time.

[0009] Optionally, the at least two light-emitting areas emit lasers with different powers or intensities.

[0010] Optionally, each of the light-emitting regions includes one or more vertical cavity surface emitting lasers.

[0011] Optionally, in one of the light emitting areas, a plurality of vertical cavity surface emitting lasers are arranged in a circle.

[0012] Optionally, in one of the light emitting areas, a plurality of vertical cavity surface emitting lasers are arranged in a rectangle.

[0013] The technical solution of the present invention also provides a light emitting unit for a laser radar, which also includes a light receiving unit; it is characterized in that the light emitting unit includes: a first light-emitting area; a second light-emitting area; the first light-emitting area and the second light-emitting area are different in relative size, and the first light-emitting area and the second light-emitting area form the same light-emitting channel to detect targets at different distances respectively.

[0014] Optionally, the second light-emitting area is farther away from the light receiving unit of the laser radar than the first light-emitting area.

[0015] Optionally, the first light-emitting area is a circular light-emitting area.

[0016] Optionally, the second light-emitting area is a rectangular light-emitting area.

[0017] Optionally, the circular light-emitting area includes a plurality of vertical cavity surface emitting lasers, and the plurality of vertical cavity surface emitting lasers are arranged in a honeycomb array in the circular light-emitting area.

[0018] Optionally, the second light emitting area includes one or more vertical cavity surface emitting lasers, and the multiple vertical cavity surface emitting lasers are arranged in a matrix or alternating manner.

[0019] Optionally, the diameter of the circular light-emitting area is in the range of 200 microns to 300 microns.

[0020] Optionally, the light emitting unit includes a first end close to the light receiving unit and a second end away from the light receiving unit, the first end to the second end is a first direction, the light emitting unit includes a light emitting surface, and the direction perpendicular to the first direction within the light emitting surface is a second direction; the size of the second light emitting area along the second direction is smaller than the size of the first light emitting area in the second direction.

[0021] Optionally, a size of the second light emitting area in the first direction is within a range of 50 micrometers to 100 micrometers, and a size of the second direction is within a range of 50 micrometers to 100 micrometers.

[0022] Optionally, the light emitted by the circular light-emitting area is reflected by an object at the farthest target detection distance of the laser radar, and the light spot formed on the receiving unit falls into the receiving unit, and the size of the light spot is not larger than the size of the receiving unit.

[0023] Optionally, a center distance between the first light-emitting area and the second light-emitting area is within a range of 150 micrometers to 200 micrometers.

[0024] Correspondingly, the technical solution of the present invention also provides a laser radar, including: a light emitting unit for providing transmitted light; and at least one light receiving unit, corresponding to the light emitting unit, for detecting an echo beam formed after the transmitted light passes through a target object.

[0025] Optionally, the light receiving unit includes a photosensitive surface, and the photosensitive surface is a circular surface.

[0026] Optionally, the light receiving unit is a silicon photomultiplier tube or a single photon avalanche diode array.

[0027] Optionally, the light receiving unit is configured such that the center of the circular surface coincides with the center of a light spot formed when the light beam emitted by the first light-emitting area is reflected by a target object at the farthest target detection distance of the laser radar, and the size of the photosensitive surface is not smaller than the size of the light spot.

[0028] Optionally, it also includes: a first optical component located downstream of the optical path of the light emitting unit, which shapes the light emitted by the light emitting unit before emitting it; and a second optical component located upstream of the optical path of the light receiving unit, which converges the echo light beam to the light receiving unit.

[0029] Optionally, the emitted light from the first light-emitting area and the second light-emitting area is shaped into a beam of light through the first optical component and emitted.

[0030] Optionally, it further includes: an aperture stop located between the second optical component and the light receiving unit and at the focal plane of the second optical component.

[0031] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0032] The light emitting unit of the embodiment of the present invention includes: a first light-emitting area, and a second light-emitting area is provided on the side of the first light-emitting area away from the light receiving unit, which is used to provide emitted light for supplementary measurement of the short-range blind area of the laser radar of the first light-emitting area, and the first light-emitting area and the second light-emitting area form the same light-emitting channel. The embodiment of the present invention adds the second light-emitting area on the side of the first light-emitting area located in the same light-emitting channel away from the light receiving unit, so that the light source of the light generating unit becomes a long light source, thereby achieving short-range blind spot compensation for the first light-emitting area. On the one hand, it reduces the blind spot of the laser radar; on the other hand, compared with the solution of compensating for the blind spot by increasing the power of the light-emitting unit, the embodiment of the present invention reduces the light emission power.

[0033] In the optional solution, the photosensitive surface of the laser radar is a circular surface, which matches the shape of the light spot formed by the echo light spot on the light receiving unit, so that more light spot energy can fall into the photosensitive surface, thereby increasing the amount of echo signal received by the light receiving unit, thereby enhancing the far-field detection capability; in addition, because the embodiment of the present invention can make a larger area of light spot detected by the photosensitive surface, it fully utilizes the light energy of the emitted light for detection, thereby reducing the emission power of the light emitting unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the laser radar optical path;

[0035] Figure 2 This is another schematic diagram of the laser radar optical path

[0036] Figure 3 is a schematic diagram of the optical path of a light emitting unit according to an embodiment of the present invention;

[0037] Figure 4 is a top view of a light emitting unit according to a first embodiment of the present invention;

[0038] Figure 5 is a top view of another light emitting unit according to an embodiment of the present invention;

[0039] Figure 6 yes Figure 3 Schematic diagram of the principle of blind spot filling in the second luminous area;

[0040] Figure 7a-7c yes Figure 3 Schematic diagram of light spots formed by light emitted by a light emitting unit passing through targets at different distances. DETAILED DESCRIPTION

[0041] As mentioned in the background technology, laser radar has the problem of high transmission power. Figure 1 Schematic diagram of the laser radar optical path, analyzing the reasons for the high laser radar transmission power.

[0042] The light emitting unit 1 includes multiple lasers for providing emission light directed toward the target S1 (or S2). The emission light is shaped by the first optical component 3 and reaches the target S1 (or S2). Thereafter, the emission light is reflected by the target S1 (or S2) to form an echo beam. The echo beam is converged onto the light receiving unit 2 through the second optical component 4 and detected by the light receiving unit 2, thereby achieving distance detection of the target S1 (or S2). Existing lidars that use SiPM or SPAD arrays as light receiving units have extremely high sensitivity. A single photon can trigger the avalanche of the SPAD unit. In addition, based on considerations of improving the signal-to-noise ratio, the photosensitive surface size of the light receiving unit 2 is relatively small. The light receiving unit is placed within the range of the light spot formed by the echo beam, and receives part of the light spot energy to obtain an echo signal for photoelectric conversion and distance measurement.

[0043] Figure 1 The circular dotted box in the middle shows a schematic diagram of the light spot 5 (or 5') formed by the echo light beam on the light receiving unit 2 and the photosensitive surface 6 of the light receiving unit 2. The light spot 5 (or 5') formed by the target S1 (or S2) is larger than the area of the photosensitive surface 6, and a part of the light spot 5 (or 5') is detected by the photosensitive surface 6, so that the target S1 (or S2) can be detected. However, a part of the light spot 5 (or 5') is outside the range of the photosensitive surface 6 and cannot be detected by the photosensitive surface 6. This solution is usually used for short-range laser radars, but for medium and long-range laser radars, Figure 1 The laser radar shown does not fully utilize the emitted light of the laser for distance detection. The light spot formed by the reflection of the target in the medium and long distance range is small in size and low in energy. Detecting only a small part of the light spot energy cannot obtain sufficient effective information.

[0044] In addition, there are blind spots when LiDAR is performing close-range detection. Figure 1 In the optical path diagram, the light emitting unit 1 and the light receiving unit 2 in the laser radar are arranged in the same direction, and the transmitting end and the receiving end each have optical components to form a paraxial optical path. The paraxial optical path can achieve the isolation and non-interference of light emission and reception. However, the paraxial optical path has a near-far effect, that is, when the distance to the target object changes, the light spot of the echo light beam on the photosensitive surface will move. Figure 1 As shown, a distant target S1 forms a light spot 5 on the light receiving unit 2, while a relatively close target S2 forms a light spot 5' on the light receiving unit 2. In other words, as the distance to the target decreases, the light spot moves away from the light emitting unit 1. When the target distance decreases to a critical distance, the light spot moves beyond the photosensitive surface 6 of the light receiving unit 2, making it undetectable by the LiDAR. This means that the LiDAR cannot detect targets within the critical distance, resulting in a blind spot.

[0045] Specifically, refer to Figure 2 , there is a target in the close-range blind zone. The image point formed by the signal light reflected from the close-range target through the receiving lens is not on the focal plane of the receiving lens (the position of the light receiving unit in the figure), but behind the focal plane. Figure 2 In the perspective of , the close-range target is above the optical axis of the receiving lens, so the image point formed by it through the receiving lens must be below the optical axis of the receiving lens. Taking these two aspects into consideration, the relative position of the focal point of the reflected light from the close-range target and the light receiving unit is as follows: Figure 2 As shown in the figure, within the close-range blind zone of the LiDAR, the LiDAR light receiving unit cannot receive the target's reflected signal at all.

[0046] The existing technology for the close-range blind spot of the laser radar uses a folding prism or optical fiber to deflect a portion of the light to the close-range blind spot for supplementary measurement, or sets two or more light emitting units in a transmission channel to emit detection light in different directions, so that the target in the blind spot can reflect a portion of the detection light and be received by the light receiving unit. It can be seen that the existing technology requires the installation of additional optical elements for blind spot supplementary measurement, while the present application uses a single laser light source to achieve the detection of targets at different distances. On the basis of reducing the close-range blind spot, it eliminates the need for additional blind spot supplementary optical elements, which can reduce the system complexity of the laser radar, reduce production costs and assembly difficulty.

[0047] To solve the above technical problems, a laser light source according to an embodiment of the present invention includes at least two light-emitting areas, wherein the at least two light-emitting areas have different relative sizes. Here, “different relative sizes” means that the light-emitting areas have different sizes.

[0048] At least two light-emitting areas can emit lasers of different intensities or powers, which is suitable for uneven lighting requirements in a certain area.

[0049] The at least two light-emitting areas share an enable signal and are driven to emit light at the same time, thereby achieving simultaneous control of the light-emitting areas. In other embodiments, the at least two light-emitting areas may also be driven by different enable signals, thereby achieving separate control of the light-emitting areas.

[0050] Furthermore, the light emitting unit for the laser radar provided by the embodiment of the present invention includes: a first light-emitting area, and a second light-emitting area is arranged on the side of the first light-emitting area away from the light receiving unit, for providing emitted light for supplementary measurement of the blind area of the first light-emitting area, and the first light-emitting area and the second light-emitting area form the same light-emitting channel. The embodiment of the present invention adds a second light-emitting area on the side of the first light-emitting area located in the same light-emitting channel away from the light receiving unit, thereby achieving close-range blind spot compensation for the first light-emitting area, which on the one hand increases the detection range of the laser radar; on the other hand, compared with the solution of increasing the power of the light-emitting unit to compensate for the blind spot, the embodiment of the present invention reduces the light emission power; on the other hand, compared with the solution of adding a beam deflecting element to compensate for the blind spot, the embodiment of the present invention simplifies the structure of the laser radar, which can reduce assembly difficulty and production cost.

[0051] In this embodiment, the same light-emitting channel refers to the first and second light-emitting areas of the light-emitting unit sharing an enable signal and being driven to emit light simultaneously. A multi-line laser radar comprises multiple light-emitting channels and multiple corresponding receiving channels, capable of transmitting and receiving multiple laser beams for ranging. Currently, there are 4-line, 8-line, 16-line, 32-line, 64-line, and 128-line multi-line laser radars on the market. The light-emitting unit provided in this embodiment of the present invention comprises a first light-emitting area and a second light-emitting area, which serve as light sources on the same line, i.e., a single light-emitting channel, for target detection.

[0052] refer to Figure 3 , which shows a light path schematic diagram of a light emitting unit according to an embodiment of the present invention.

[0053] The light emitting unit 10 of the embodiment of the present invention is applied to a laser radar for providing emitted light for detecting a target object; the laser radar further includes a light receiving unit 20 corresponding to the light emitting unit 10 for detecting the echo light beam.

[0054] It should also be noted that for the sake of simplicity, Figure 3 Only six light emitting units 10 arranged in two rows and three columns and six corresponding light receiving units 20 arranged in two rows and three columns applied to the laser radar are illustrated, and the present invention should not be limited thereto.

[0055] Figure 3 The laser radar includes: multiple light emitting units 10, a first optical component 11, a second optical component 12, an aperture stop 13 and multiple light receiving units 20, wherein the light receiving units 20 correspond to the light emitting units 10 and are used to detect the echo light beams formed by the emitted light of the corresponding light emitting units 10.

[0056] refer to Figure 4 and Figure 5In this embodiment, the light emitting unit 10 is a planar array light source, including a light emitting surface 101 on which a plurality of light sources are formed.

[0057] Specifically, the light source on the light emitting surface 101 is a vertical-cavity surface-emitting laser (VCSEL), which is a laser that can emit laser light in a direction perpendicular to a substrate.

[0058] A VCSEL laser comprises a substrate (or baseplate) (e.g., a GaAs substrate), a resonant cavity located on the substrate, the resonant cavity comprising a bottom Bragg reflector, an active region, and a top Bragg reflector, all located sequentially on the substrate, and a light exit window above the resonant cavity. Specifically, the active region can be a quantum well, which generates photons when loaded with current. The photons oscillate in the resonant cavity to form laser light, which is then emitted through the light exit window.

[0059] In this embodiment, the VCSEL laser can emit laser light with wavelengths of 905 nm, 940 nm, etc. These wavelengths are outside the visible light wavelength range, thus preventing the influence of visible light on target detection.

[0060] The multiple VCSEL lasers of the light emitting unit 10 are arranged in an array pattern to form a first light emitting area 1011 for emitting emission light F for detecting the target object S.

[0061] It should be noted that, on the one hand, the light spot formed by the reflected light F from targets beyond the maximum target detection range cannot be detected; on the other hand, due to the near-far effect of the laser radar, the first light-emitting area 1011 cannot achieve close-range detection, resulting in a blind spot. Therefore, the emitted light provided by the first light-emitting area 1011 can detect targets within a detection range. Distances smaller than this detection range are defined as the blind spot of the first light-emitting area 1011.

[0062] It should be noted that the multiple VCSEL lasers located in the first light-emitting area 1011 have their emission light from adjacent lasers passing through the target object, forming echo beams that intersect on the photosensitive surface 102, forming a light spot of a certain area (not shown) on the photosensitive surface 102. The shape of the photosensitive surface 102 matches the shape of the first light-emitting area 1011.

[0063] exist Figure 4 In the embodiment shown, the first light-emitting area 1011 is a circular light-emitting area. Accordingly, the emitted light F emitted by the entire first light-emitting area 1011 is a circular light beam.

[0064] exist Figure 5In the embodiment shown, the first light emitting area 1011 may also be rectangular.

[0065] Specifically, the multiple VCSEL lasers in the first light-emitting area 1011 are arranged in a honeycomb array. This arrangement effectively utilizes the area of the first light-emitting area 1011, arranging more lasers; it also ensures that the light emitted from the first light-emitting area 1011 has good uniformity. In other embodiments, the multiple VCSEL lasers in the first light-emitting area can also be arranged in other ways, such as a matrix arrangement.

[0066] It should be noted that if the size of the first light-emitting area 1011 is too large, the spot size of the emitted light beam will also be larger, and the required optical components and light receiving unit 20 will also be increased accordingly, increasing the size and weight of the LIDAR system. In addition, the power of the emitted light beam will be too high, which may cause eye safety issues. If the size of the first light-emitting area 1011 is too small, the number of lasers in the first light-emitting area 1011 will also be small, and the emitted light power will be low, which will affect the detection range of the LIDAR. Accordingly, in this embodiment, the diameter of the circular first light-emitting area 1011 is within the range of 200 microns to 300 microns.

[0067] In this embodiment of the present invention, the first luminous area 1011 is configured such that light emitted from the circular luminous area is reflected by an object at the farthest target detection distance of the laser radar, forming a light spot on the receiving unit that falls within the receiving unit, and the size of the light spot is no larger than the size of the receiving unit. This allows full utilization of the emitted light F for detection, improves light utilization, and reduces light transmission power.

[0068] The light emitting unit of the embodiment of the present invention also includes a second light emitting area 1012, which is located on the side of the first light emitting area 1011 away from the light receiving unit 20, and is used to provide emitted light for supplementary measurement of the blind area of the first light emitting area 1011 (supplementary measurement of the blind area can be simply referred to as blind filling).

[0069] Combined with reference Figure 6 The light emitting unit 10 is configured to be close to the light receiving unit 20 as a first end A1, and away from the light receiving unit 20 as a second end A2. The first end A1 to the second end A2 is a first direction X. The light emitting surface 101 includes the second light emitting area 1012 on the side away from the light receiving unit 20 in the first direction X.

[0070] The second light emitting area 1012 includes one or more vertical cavity surface emitting lasers, and the light emitted by the second light emitting area 1012 is used to perform supplementary detection on a close-range target located in a blind area of the first light emitting area.

[0071] The following reference Figure 6The optical path diagram shown illustrates the principle of the second light-emitting area 1012 performing supplementary measurement on the blind area.

[0072] like Figure 6 As shown, the emitted light F1 of the first light-emitting area 1011 forms an echo beam B1 through the close-range target object S2. The echo beam B1 cannot fall into the photosensitive surface, that is, it exceeds the detection range of the light receiving unit 20. Therefore, the close-range target object S2 cannot be detected by the light receiving unit of the laser radar, and enters the detection blind spot of the laser radar.

[0073] In this embodiment, the light-emitting surface 101 further includes a second light-emitting area 1012 on a side away from the light-receiving unit 20 in the first direction X, which is equivalent to extending the entire light-emitting area of the light-emitting unit 10 along the first direction X, thereby forming a light spot extending along the first direction X. In this way, even if the light spot of the first light-emitting area 1011, which is primarily used for distance detection, has moved outside the photosensitive surface, the light F2 emitted by the second light-emitting area 1012 can still be detected by the light-receiving unit 20 after passing through the close-range target S2 to form an echo beam B2, thereby obtaining distance information of the close-range target S2 and realizing detection of the close-range target S2.

[0074] Please continue to refer to Figure 3-Figure 4 In this embodiment, the first light-emitting area 1011 is a circular light-emitting area, and the second light-emitting area 1012 is a rectangular light-emitting area.

[0075] The first direction X is from the first end A1 to the second end A2 , and the direction perpendicular to the first direction X on the light emitting surface 201 is the second direction Y.

[0076] Multiple vertical cavity surface emitting lasers (VCSELs) are arranged in a matrix within the rectangular second light-emitting area 1012. This rectangular second light-emitting area 1012 extends in the first direction X, providing blind spots. Furthermore, it allows for the arrangement of lasers in columns along the second direction Y, ensuring uniform light emission.

[0077] Here, the matrix arrangement includes a one-dimensional matrix (ie, linear array) arrangement and a multi-dimensional matrix (ie, area array) arrangement.

[0078] It should be noted that, in other embodiments, the second light emitting area 1012 may also be in other shapes, such as an ellipse or a trapezoid, etc. In addition, the multiple lasers located in the second light emitting area may also be arranged in an alternating manner or in a honeycomb array.

[0079] It should also be noted that in this embodiment, the second light-emitting area 1012 includes multiple lasers. In fact, the second light-emitting area 1012 can play a blind spot filling role as long as there is a laser. In other embodiments, only one laser can be set in the second light-emitting area 1012.

[0080] The following reference Figure 7a-7c Shown Figure 3 The position relationship diagram of the light spot formed by the light emitting unit and the photosensitive surface illustrates the working principle of the light emitting unit. Specifically, Figure 7a 、 Figure 7b 、 Figure 7c The light spots produced by long-distance targets, medium-distance targets, and close-distance targets are respectively illustrated.

[0081] It should be noted that in actual application, the position of the light receiving unit 20 remains unchanged, and the position of the corresponding photosensitive surface also remains unchanged. Figure 7a-7c When the target object moves from far to near, the light spot 103 generated by the target object will move in a direction away from the light emitting unit 10 .

[0082] like Figure 7a As shown, the first light-emitting area 1011 and the second light-emitting area 1012 are shaped to form a beam of light, and the light spot 203 generated by reflection from the target intersects. In this embodiment, the first light-emitting area 1011 is circular, and the circular light spot formed is located within the photosensitive surface 202, which is used for detecting distant targets. The second light-emitting area 1012 is rectangular, and the rectangular light spot formed by reflection from a distant target (e.g., any distance within 60-100 meters) is located outside the photosensitive surface 202.

[0083] like Figure 7b As shown, as the distance to the target object decreases, the light spot 203 formed by the circular first light-emitting area 1011 and the rectangular second light-emitting area 1012 moves toward a direction away from the light emitting unit 10, wherein a portion of the circular light spot generated by the circular first light-emitting area 1011 moves out of the photosensitive surface 202, and the circular light spot located within the photosensitive surface 202 still has sufficient light intensity to be detected by the photosensitive surface 202. In addition, a portion of the light spot 203 formed by the rectangular second light-emitting area 1012 is also detected within the photosensitive surface 202, thereby facilitating the detection of medium-distance targets (for example, in the range of 0.3 to 30m).

[0084] like Figure 7cAs the distance to the target object further decreases, the light spot 203 also moves further away from the light emitting unit 10 accordingly, wherein the light spot 203 formed by the circular first light-emitting area 1011 completely moves out of the photosensitive surface 202, while the rectangular light spot formed by the rectangular second light-emitting area 1012 is located within the photosensitive surface 202, which is used to detect close-range targets (for example, less than 0.3m) located in the blind spot, thereby compensating for the close-range area that cannot be detected by the emitted light of the first light-emitting area 1011, thereby achieving the purpose of filling the blind spot at close range.

[0085] It should be noted that the values here are only examples. LiDARs using devices with different parameters have different ranging capabilities, and their possible definitions of long, medium and short distances are different.

[0086] The following reference Figure 4 shown Figure 3 The top view of the light emitting unit 10 is further described.

[0087] like Figure 4 As shown, in the light emitting unit of the embodiment of the present invention, the size of the second light-emitting area 1012 along the second direction Y is smaller than the size of the first light-emitting area 1011 in the second direction Y. Specifically, the length of the rectangular second light-emitting area 1012 along the Y direction is smaller than the diameter of the circular first light-emitting area 1011.

[0088] Because the light source in second luminous area 1012 is used to fill in the blind spots of close-range targets in the laser radar's blind spot, and compared to distant targets, the light emitted by a light source of the same size forms a larger light spot after reflection from a close-range target. Therefore, a smaller size of second luminous area 1012 can form a light spot that can be detected by the photosensitive surface. This can improve the long-range ranging capability of the laser radar and reduce the close-range blind spot, resulting in a laser radar with excellent ranging performance within the target detection range.

[0089] In this embodiment, a second light emitting area 1012 of a smaller size can be provided, thereby reducing the number of lasers in the light emitting unit 10 and further reducing the laser emission power.

[0090] In addition, if Figure 4 As shown, in this embodiment, a bonding point 1013 is provided on both sides of the second light-emitting area 1012 along the second direction Y, for loading an electrical signal to excite the first light-emitting area 1011 and the second light-emitting area 1012 to emit light.

[0091] In this embodiment, the size of the second light-emitting area 1012 along the second direction Y is smaller than the size of the first light-emitting area 1011 in the second direction Y. Therefore, the second light-emitting area 1012 has non-light-emitting regions on both sides of the second direction Y where no lasers are formed. The bonding points 1013 are formed in these non-light-emitting regions, fully utilizing the area of the light-emitting unit 10 and improving the structural compactness of the light-emitting unit 10.

[0092] It should be noted that if the size of the second light-emitting area 1012 is too small, the blind spot compensation effect is not ideal; if the size of the second light-emitting area 1012 is too large, the number of lasers is easily increased, resulting in waste of optical power. In this embodiment, the size of the second light-emitting area 1012 in the first direction X is within the range of 50 microns to 100 microns, and the size in the second direction Y is within the range of 50 microns to 100 microns.

[0093] In this embodiment, the emitted light from the first light-emitting area 1011 and the second light-emitting area 1012 is formed into a beam of light and then emitted. After being reflected by the target object, the light spots formed on the photosensitive surface 202 intersect, thereby ensuring that the light spot formed by the light emitting unit 21 is detected as a whole by the corresponding light receiving unit 20, thereby ensuring the effective detection of the light spot by the light receiving device.

[0094] It should be noted that when detecting a target that is closer, the size of the light spot formed by the reflection becomes larger. Therefore, in actual applications, for a target at the farthest target detection distance, the light spots generated by the first light-emitting area 1011 and the second light-emitting area 1012 can intersect. When detecting a target at a closer distance, the corresponding light spots will have more overlapping areas because of their larger size.

[0095] Specifically, the spacing between the first light-emitting area 1011 and the second light-emitting area 1012 can be set to ensure that the light spots of the two light-emitting areas intersect. It should be noted that if the spacing between the first light-emitting area 1011 and the second light-emitting area 1012 is too large, it is easy for the light spots generated by the two light-emitting areas to not intersect. If the spacing between the first light-emitting area 1011 and the second light-emitting area 1012 is too small, it is easy for the light spots to have too much overlapping areas, resulting in waste of light energy. In this embodiment, the center-to-center spacing between the first light-emitting area 1011 and the second light-emitting area 1012 is within the range of 150 microns to 200 microns.

[0096] In order to solve the technical problem, the embodiment of the present invention further provides a laser radar, such as Figure 3 As shown, the laser radar includes: a light emitting unit of an embodiment of the present invention, used to provide emitted light F; the emitted light F is reflected by the laser radar target S to form an echo beam B, and the laser radar also includes: at least one light receiving unit 20, corresponding to the light emitting unit 10, used to detect the emitted light F corresponding to the light emitting unit 10.

[0097] The light receiving unit 20 includes a photosensitive surface 102 for detecting the echo beam B. The light receiving unit 20 includes a photosensitive surface, using Figure 4 In the light emitting unit 10 , the photosensitive surface 102 is a circular surface.

[0098] Combined with reference Figure 3 and Figure 4 The photosensitive surface 102 of the laser radar is a circular surface, which matches the shape of the light spot formed by the echo light spot on the light receiving unit 20, so that more light spot energy can fall into the photosensitive surface 102, thereby increasing the amount of echo signal received by the light receiving unit 20, thereby enhancing the far-field detection capability; in addition, because the embodiment of the present invention can make more light spot energy be detected by the photosensitive surface 102, it fully utilizes the light energy of the emitted light for detection, which can reduce the emission power of the light emitting unit.

[0099] like Figure 3-Figure 4 As shown, in this embodiment, the first light-emitting area 1011 is a circular light-emitting area, and the photosensitive surface 102 is a circular surface. The shapes of the first light-emitting area 1011 and the photosensitive surface 102 match, so that the light spot 103 can match the shape of the photosensitive surface 102, thereby increasing the probability of the light spot 103 being detected by the photosensitive surface 102, so that almost all the energy of the light spot 103 is received by the photosensitive surface 102, thereby improving the utilization rate of light energy and enhancing the quality of long-distance signals.

[0100] In this embodiment, the light receiving unit 20 sets the size of the photosensitive surface 102 to be no less than the size of the light spot formed by the reflection of the target object at the farthest target detection distance of the laser radar.

[0101] Specifically, the echo beam B is projected onto the photosensitive surface 102 of the light receiving unit 20 to form a light spot. The photosensitive surface 102 converts the optical signal of the light spot into an electrical signal, and then processes and calculates the electrical signal to detect the distance of the target object.

[0102] In the laser radar of the embodiment of the present invention, the light receiving unit 20 and the light emitting unit 10 are configured in coordination with each other to ensure that the photosensitive surface 102 is no smaller than the aforementioned spot size. It should be noted that the maximum target detection distance is a parameter of the laser radar and one of its design specifications. Here, the position and area of the photosensitive surface 102 of the light receiving unit 20 are set based on the target at the maximum target detection distance. This ensures that the return beam from the target at the maximum target detection distance forms a spot within the photosensitive surface 102.

[0103] like Figure 7a-7cAs shown, the light receiving unit 20 can be set as follows: the center of the circular surface coincides with the center of the light spot formed by the light beam emitted by the first light-emitting area 1011 and reflected by the target object at the farthest target detection distance of the laser radar, and the size of the photosensitive surface is not less than the size of the light spot.

[0104] In an embodiment of the present invention, the light receiving unit is configured so that almost all of the light spots formed by the reflection of the target object at the farthest target detection distance of the laser radar fall within the photosensitive surface. In this way, when the laser radar detects a long-distance target, the light spot falls within the photosensitive surface, thereby increasing the amount of echo signal received by the light receiving unit and enhancing the far-field detection capability; when detecting a medium-distance target, most of the light spots are located within the photosensitive surface and can be detected; when detecting a close-range target, part of the light spots can also be located within the photosensitive surface to achieve close-range detection. Therefore, the embodiment of the present invention makes full use of the light energy of the emitted light for detection, thereby improving the long-distance ranging capability of the laser radar and reducing the transmission power of the light emitting unit.

[0105] In this embodiment, the light spot formed by the reflection of the target object at the farthest target detection distance is used as a reference to set the position and size of the photosensitive surface 102 in the light receiving unit 20. By setting the centers of the two to coincide, it can be ensured that the photosensitive surface 102 can effectively detect the light spot, and can fully utilize the emitted light of the first light-emitting area 1011 for distance detection.

[0106] In this embodiment, the size of the photosensitive surface 102 is not smaller than the size of the light spot, so that the light spot can be located within the photosensitive surface 102 to improve the utilization rate of light energy, thereby improving the distance measurement capability on the one hand and reducing the light emission power on the other hand.

[0107] In an embodiment of the present invention, the light receiving unit 20 is a silicon photomultiplier (SiPM) or a single photon avalanche diode (SPAD) array, both of which are planar arrays and are photodetectors with extremely high sensitivity. Compared with traditional avalanche photodiodes, they can reduce the photosensitive surface area required for lidar detection, thereby reducing the size of the light receiving unit, which is conducive to the development needs of miniaturization of lidar.

[0108] like Figure 3 As shown, the laser radar further includes: a first optical component 11, located downstream of the optical path of the light emitting unit 10, for shaping the emitted light F of the light emitting unit 10 and projecting it onto the target object S.

[0109] In this embodiment, the emitted light F of the first light emitting area 1011 and the second light emitting area 1012 is shaped by the first optical component 11 to form a beam of light, so that the two light spots formed by the echo beams overlap (i.e. Figures 7a-7c There is no gap between the circular spot and the rectangular spot to reduce missed detection of targets in close range areas.

[0110] Specifically, the first optical component 11 may include optical elements such as a lens and a collimator.

[0111] Continue to refer Figure 3 In this embodiment, the laser radar also includes: a second optical component 12, located upstream of the optical path of the light receiving unit 20, for converging the echo light beam B to the light receiving unit 20, thereby increasing the light intensity of the echo light beam B, which is beneficial to increasing the maximum detection distance of the laser radar and improving the quality of long-distance detection.

[0112] The laser radar of this embodiment further includes: an aperture stop 13 , which is located between the second optical component 12 and the light receiving unit 20 and at the focal plane of the second optical component 12 .

[0113] It should be noted that, usually, the surface array of the light receiving unit 20 is also located at the focal plane position of the second optical component 12. The aperture stop 13 of this embodiment is used to limit the echo light beam B and filter out stray light so that the light spot generated by the echo light beam B is located within the range of the photosensitive surface 102.

[0114] In this embodiment, an aperture stop 13 is provided. The aperture's aperture restricts the light beam, creating a circular spot. By designing both the photosensitive surface 102 and the first luminous area 1011 to be circular, more light can pass through the aperture stop 13, thereby improving light utilization and avoiding wasted light energy. The circular shape of the first luminous area 1011 facilitates shaping of the emitted light beam, reduces its divergence angle, and increases the echo signal power, thereby enhancing the long-range ranging capability of the LIDAR.

[0115] It should be noted that, in this embodiment, the circular light spot formed by the circular first light-emitting area 1011 matches the shape of the aperture stop 13, so a smaller aperture stop can be used (for example, compared with the rectangular light-emitting area, the aperture stop is equivalent to the diagonal of the rectangle, so there is a larger gap between the inner diameter of the aperture stop and the edge of the rectangular light spot), thereby improving the accuracy of the light.

[0116] In other embodiments, the laser radar may not be provided with the aperture stop, and the light spot can be made to fall into the photosensitive surface by configuring the relative relationship between the light emitting unit and the light receiving unit.

[0117] It should also be noted that in other embodiments, the first light-emitting area may also be a regular polygon (e.g., a pentagon, a hexagon, etc.) or an ellipse. Accordingly, the photosensitive surface may also be of other shapes, and the photosensitive surface may not match the shape of the first light-emitting area. For example, the first light-emitting area may be a regular hexagonal light-emitting area, and the photosensitive surface may be a circular surface; or the first light-emitting area may be an elliptical light-emitting area, and the photosensitive surface may be an elliptical surface.

[0118] It should be noted that in the above embodiment, the laser radar includes multiple light emitting units and corresponding multiple light receiving units. In other embodiments, there may be only one light emitting unit and a corresponding light receiving unit.

[0119] In the laser radar of the embodiment of the present invention, the light emitting unit and the light receiving unit are configured with each other, so that the laser radar has a relatively small transmitting power and can also achieve long-distance detection.

[0120] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined by the claims. Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined by the claims.

Claims

1. A light emitting unit for laser radar, characterized in that: The light emitting unit includes: a first light emitting area and a second light emitting area, wherein the size of the second light emitting area is smaller than that of the first light emitting area; the first light emitting area and the second light emitting area form a same light emitting channel; The light emitting unit includes a first end close to the light receiving unit of the laser radar and a second end away from the light receiving unit, and the second light emitting area is farther away from the first end than the first light emitting area; The light emitted by the second light-emitting area is suitable for supplementing the detection blind area of the laser radar corresponding to the first light-emitting area.

2. The light emitting unit according to claim 1, wherein The first light-emitting area is a circular light-emitting area.

3. The light emitting unit according to claim 1, wherein The second light-emitting area is a rectangular light-emitting area.

4. The light emitting unit according to claim 2, wherein: The circular light-emitting area includes a plurality of vertical cavity surface emitting lasers, and the plurality of vertical cavity surface emitting lasers are arranged in a honeycomb array in the circular light-emitting area.

5. The light emitting unit according to claim 3, wherein: The second light emitting area includes one or more vertical cavity surface emitting lasers, and the plurality of vertical cavity surface emitting lasers are arranged in a matrix or alternating manner.

6. The light emitting unit according to claim 2, wherein: The diameter of the circular light-emitting area is in the range of 200 micrometers to 300 micrometers.

7. The light emitting unit according to claim 1, wherein The direction from the first end to the second end is a first direction, the light emitting unit includes a light emitting surface, and a direction within the light emitting surface that is perpendicular to the first direction is a second direction; A size of the second light-emitting area along the second direction is smaller than a size of the first light-emitting area along the second direction.

8. The light emitting unit according to claim 7, wherein: The second light emitting area has a size in the first direction ranging from 50 micrometers to 100 micrometers, and a size in the second direction ranging from 50 micrometers to 100 micrometers.

9. The light emitting unit according to claim 2, wherein: The light emitted by the circular light-emitting area is reflected by the target object at the farthest target detection distance of the laser radar, and the light spot formed on the receiving unit falls into the receiving unit, and the size of the light spot is not larger than the size of the receiving unit.

10. The light emitting unit according to claim 1, wherein The center distance between the first light emitting area and the second light emitting area is within a range of 150 micrometers to 200 micrometers.

11. A laser radar, characterized in that: include: The light emitting unit according to any one of claims 1 to 10, configured to provide emitted light; as well as At least one light receiving unit, corresponding to the light emitting unit, is used to detect an echo light beam formed after the emitted light passes through the target object.

12. The laser radar according to claim 11, wherein The light receiving unit includes a photosensitive surface, and the photosensitive surface is a circular surface.

13. The laser radar according to claim 11, wherein The light receiving unit is a silicon photomultiplier tube or a single photon avalanche diode array.

14. The laser radar according to claim 12, wherein: The light receiving unit is configured such that the center of the circular surface coincides with the center of a light spot formed by the light beam emitted by the first light-emitting area and reflected by a target object at the farthest target detection distance of the laser radar, and the size of the photosensitive surface is not smaller than the size of the light spot.

15. The laser radar according to claim 11, wherein Also includes: A first optical component is located downstream of the optical path of the light emitting unit and shapes the light emitted by the light emitting unit before emitting it; The second optical component is located upstream of the optical path of the light receiving unit and converges the echo light beam to the light receiving unit.

16. The laser radar according to claim 15, wherein: The light emitted from the first light-emitting area and the second light-emitting area is shaped into a beam of light through the first optical component and emitted.

17. The laser radar according to claim 15, wherein Also includes: An aperture stop is located between the second optical component and the light receiving unit and at a focal plane of the second optical component.

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