CN217766830U

CN217766830U - Laser emitting module and laser radar device

Info

Publication number: CN217766830U
Application number: CN202221701412.4U
Authority: CN
Inventors: 贺一鸣; 刘佳尧; 张乃川; 石拓
Original assignee: Zvision Technologies Co Ltd
Current assignee: Zvision Technologies Co Ltd
Priority date: 2022-07-04
Filing date: 2022-07-04
Publication date: 2022-11-08
Anticipated expiration: 2032-07-04

Abstract

The present disclosure relates to a laser emission module and a laser radar apparatus. A laser emitting module is provided. The laser emission module comprises a laser module and an emission bracket. The laser module comprises a Laser Diode (LD) chip and a driving circuit board. The LD chip is configured to emit a detection laser in response to an electric drive signal. The driving circuit board is configured to supply an electric driving signal to the LD chip. The emission support supports the LD chip and the driving circuit board of the laser module. The heat generated by the LD chip is conducted through the emission mount. The driving circuit board is placed to deviate from a heat conduction path from the LD chip to the emission mount.

Description

Laser emission module and laser radar device

Technical Field

The present disclosure relates to the field of laser sensing, and more particularly, to a laser transmitter module and a laser radar apparatus having the same.

Background

The laser sensing means that the characteristics of high directionality, high monochromaticity, high brightness and the like of laser are utilized to realize remote measurement. The measurement object sensed by the laser generally includes length, distance, vibration, speed, orientation, substance concentration, and the like. With the rapid development of automatic driving technology, a laser sensor, namely a laser radar device, also called a laser detection and ranging (LiDAR or LADAR) device, is receiving more and more attention. The laser radar apparatus measures information of a position, a speed, and the like of a target object by emitting a probe laser beam toward the target object and receiving a beam reflected/scattered back from the target object.

The laser emitting module of the lidar device is a crucial component. The light emitting efficiency of the laser emitting module and parameters such as the power and the divergence angle of the emitted light directly determine the performance of the laser radar device, such as the ranging precision and the ranging range. When designing a laser emitting module of a laser radar, compatibility of parameters such as optical efficiency, structural positioning realizability, heat dissipation, driving signal paths and the like needs to be considered at the same time. The reasonable design of the transmitting module can greatly improve the performance and efficiency of the laser radar.

SUMMERY OF THE UTILITY MODEL

The present disclosure provides a laser emission module and a laser radar apparatus. The laser emission module can improve the heat dissipation effect, improve the stability of light beams and reduce the assembly difficulty.

One aspect of the present disclosure relates to a laser emission module. The laser emission module comprises a laser module and an emission support. The laser module comprises a Laser Diode (LD) chip and a driving circuit board. The LD chip is configured to emit a detection laser in response to an electric drive signal. The driving circuit board is configured to supply an electric driving signal to the LD chip. The emission support supports the LD chip and the driving circuit board of the laser module. The heat generated by the LD chip is conducted through the emission mount. The driving circuit board is placed to deviate from a heat conduction path from the LD chip to the emission mount.

In some embodiments, the laser emitting module further comprises a rigid thermally conductive substrate. The LD chip is fixed to a first side of the rigid thermally conductive substrate. A second side of the rigid thermally conductive substrate opposite the first side is secured to the emitter support. The driving circuit board is placed to deviate from a heat conduction path from the LD chip to the emission mount via the rigid heat conduction substrate.

In some embodiments, the rigid thermally conductive substrate is at least one of a ceramic substrate, an aluminum nitride substrate, or an aluminum oxide substrate.

In some embodiments, the rigid thermally conductive substrate is substantially insulating.

In some embodiments, the LD chip receives the electrical drive signal from the drive circuit board via an electrically conductive trace on the rigid thermally conductive substrate.

In some embodiments, the LD chip and the driving circuit board are positioned on the same side of the emission cradle.

In some embodiments, the driving circuit board and the LD chip are distributed at a distance in a plane parallel to the same side.

In some embodiments, the emissive support is made of a metallic material.

In some embodiments, the driving circuit board may include a resin material.

In some embodiments, the driving circuit board is electrically connected to the LD chip by wire bonding to supply an electric driving signal to the LD chip.

In some embodiments, the laser emission module further includes beam shaping optics configured to beam-shape the probe laser emitted by the LD chip. The emission support also supports beam shaping optics.

Another aspect of the disclosure relates to a lidar apparatus. The lidar device comprises a laser transmit module, a scanner, a laser receive module and a controller as described hereinbefore. The scanner is configured to direct the detection laser light from the laser emission module to scan the target object. The laser receiving module is configured to detect detection laser light reflected by the target object to output an electrical detection signal. The controller is configured to communicatively couple and control the laser emitting module, the scanner, and the laser receiving module.

Drawings

The above and other objects and advantages of the present disclosure will be further described with reference to the accompanying drawings in conjunction with the specific embodiments. In the drawings, the same or corresponding technical features or components will be denoted by the same or corresponding reference numerals.

Fig. 1 shows a typical structure diagram of a prior art laser emission module;

FIGS. 2A and 2B are schematic diagrams showing two typical structures of a prior art laser module;

fig. 3 shows a schematic structural diagram of a laser emission module according to an embodiment of the present disclosure;

fig. 4 shows a schematic structural diagram of a laser emission module according to an embodiment of the present disclosure;

FIG. 5 illustrates one exemplary implementation of a laser emitting module forming an electrical connection structure for transmitting an electrical drive signal in accordance with an embodiment of the present disclosure;

FIGS. 6A and 6B show perspective and top views, respectively, of one non-limiting example structure in which a laser emission module further includes beam shaping optics, according to embodiments of the present disclosure;

fig. 7 shows a flow chart of a method for manufacturing a laser emitting module according to an embodiment of the present disclosure; and

fig. 8 shows a schematic structural diagram of a lidar apparatus according to an embodiment of the disclosure.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and therefore are only used as examples, and the protection scope of the present invention is not limited thereby. The words and phrases used in the following description are used only to provide a clear and consistent understanding of the disclosure. In addition, descriptions of well-known structures, functions, and configurations may be omitted for clarity and conciseness.

Laser emission modules generally have three types of application scenarios: laser communication, laser sensing, and laser machining. In the field of laser communication, the power of a light source is lower than that of other two application scenes, the heat dissipation problem is not obvious, and the requirements on positioning and aligning of laser beams are not high because the power of the light source is not required to be used for accurate measurement. In the field of laser processing, the power of a light source is higher than that of other two application scenes, and the heat dissipation requirement is higher, but the requirements on positioning and aligning of laser beams are also not high, so that the heat dissipation requirement can be generally met by additionally arranging a heat dissipation structure. However, in the field of laser sensing, the light source heat dissipation needs to be considered, and the problems of light beam positioning and alignment need to be considered. It is therefore necessary to design a laser emitting module that is capable of and suitable for use in laser sensing applications. A typical structure of the conventional laser transmitter module and the corresponding problems will be described with reference to fig. 1 and 2A to 2B.

Fig. 1 shows a typical structure diagram of a laser transmitter module of the prior art. The laser emitting module 100 includes a laser module 101 and an optical device 103 in sequence along a traveling direction of an optical path (i.e., an optical axis direction of a laser beam emitted by a laser). The laser module 101 emits a detection laser beam, which is optically processed by one or more optical devices 103 and then emitted. The laser module 101 and the optics 103 are both directly or indirectly fixed to the emission support 102. Alignment of the laser module 101 with the optics 103 is critical to enable the optics 103 to perform precise optical processing of the laser beam emitted by the laser module 101 as desired. Since the laser module 101 and the optical device 103 are both mounted on the emitting bracket 102, a change in the relative position of any one of the laser module 101 and the optical device 103 with respect to the emitting bracket 102 will affect the alignment effect, and thus cause a change in the shape, position or power of the light beam finally emitted by the laser emitting module 100. If the laser transmitter module 100 is used in a laser radar, the accuracy and range of the measurement may be affected. Compared with the optical device 103 which is usually a passive device, the laser module 101 as an active device has an operation condition which is easier to change, and thus a relative position change with respect to the emission support 102 is easier to occur. It is therefore desirable that the laser module 101 provide stable structural support for a Laser Diode (LD) chip as a light emitting element therein, and ensure that the LD chip can still maintain stable position under different working conditions, thereby ensuring stability of the emitted light beam.

The laser module needs to provide an electric driving signal for the LD chip to cause light emission, and thus further includes a driving circuit board providing the electric driving signal. In addition, the LD chip generates heat as a high power device, and therefore, the laser module needs to provide heat conduction for the LD chip.

The laser module 101 generally has two typical implementation structures, which are shown in fig. 2A and fig. 2B, respectively. In both configurations, the LD chip is mounted directly or indirectly on the driving circuit board, and then both are mounted as a whole on the emission stand. In fig. 2A, the laser module includes a three-layer structure including an LD chip 201, a ceramic substrate 204, and a driving circuit board 202 in this order in a direction from being far from an emission mount 203 to being close to the emission mount 203 (from top to bottom in the drawing). In fig. 2B, the laser module includes a two-layer structure, i.e., no ceramic substrate 204 is disposed between the LD chip 201 and the driving circuit board 202. In fig. 2A and 2B, the driving circuit board 202 supplies an electric driving signal 205 to the LD chip.

The structure of the existing laser module has the following problems:

(1) The heat dissipation path is long and the thermal resistance is large. No matter the two-layer structure or the three-layer structure, because the LD chip is always arranged on the driving circuit board, the heat from the LD chip must pass through the driving circuit board and can finally reach the emission support. The driving circuit board becomes a bottleneck in a heat dissipation path. This is because the longitudinal thermal conductivity of the drive circuit board tends to be very low, causing a large amount of heat to accumulate on the drive circuit board. This will eventually cause the temperature of the LD chip to be too high, which may affect the normal operation of the LD chip and even cause failure.

(2) The structure is complex and the structural stability is poor. No matter the structure is a two-layer structure or a three-layer structure, because the driving circuit board is inserted between the LD chip and the emitting bracket, the volume change of the driving circuit board during temperature change finally affects the relative positions of the LD chip and the emitting bracket, and further affects the alignment of the LD chip and the optical device arranged on the emitting bracket. The resulting optical path variations will ultimately affect beam shape, position and power.

(3) The laser module with the two-layer structure has stress risk. As shown in fig. 2B, since there is no ceramic substrate between the LD chip and the driving circuit board, the expansion or contraction of the driving circuit board in the horizontal direction (parallel to the mounting surfaces of the driving circuit board and the emission bracket) may be transmitted to the LD chip through the wires connected to the LD chip for transmitting the electric driving signal 205, resulting in different stresses to which the LD chip is subjected at different temperatures, thereby causing a change in the far-field divergence angle of the laser beam emitted by the LD chip, and further causing a change in the shape, position, and power of the finally output beam.

To overcome at least one of the above drawbacks, the present disclosure proposes laser emission modules having different structures. In the laser emission module, the driving circuit board for supplying the LD chip with the electric driving signal is deviated from, i.e., is no longer disposed on, the heat conduction path from the LD chip to the emission mount. Thus, the driving circuit board is no longer a heat dissipation bottleneck. Meanwhile, the problem that the laser beam is influenced due to the fact that the laser beam is influenced by stress change of the LD chip caused by the fact that the relative position of the LD chip and the emission support is finally influenced by the fact that the driving circuit board is subjected to volume change due to heat accumulation and horizontal deformation of the driving circuit board is eliminated or relieved. The laser emission module according to the present disclosure may be particularly applicable to the field of laser sensing.

Fig. 3 shows a schematic structural diagram of a laser emission module 300 according to an embodiment of the present disclosure. The laser emitting module 300 includes a laser module and an emitting bracket 303. The laser module is used for launching detection laser, and the launching support 303 is used for supporting the laser module. Specifically, the laser module may include an LD chip 301 and a driving circuit board 302.

The LD chip 301 is for emitting a detection laser in response to an electric drive signal 305. The LD chip 301 may be various semiconductor laser chips including, but not limited to: edge-emitting lasers (such as fabry-perot (FP) cavity lasers, distributed Feedback (DFB) lasers, etc.) and surface-emitting lasers (such as Vertical Cavity Surface Emitting (VCSEL) lasers, etc.). The detection laser light emitted by the LD chip 301 may be any one of pulsed light, continuous light, or quasi-continuous light. The operating wavelength of the detection laser may be any wavelength of light, including, for example, 650nm to 1150nm, 800nm to 1000nm, 850nm to 950nm, or 1300nm to 1600nm. When applied to a laser radar apparatus, the operating wavelength of the LD chip may be, for example, 905nm and 1550nm. In some embodiments, the LD chip 301 may be without an encapsulation structure. In this case, the LD chip 301 is more likely to affect light emission due to stress of other structures in contact therewith.

The driving circuit board 302 is used for providing an electric driving signal 305 for the LD chip 301. In some embodiments, the driving circuit board 302 may include a resin material. In particular, the driver circuit board 302 may be based on a composite material composed of a dielectric layer and a conductor. Typical examples of the dielectric layer include resin materials, which may include but are not limited to: thermosetting resins such as phenol resin, epoxy resin, polyimide resin, and polytetrafluoroethylene (PTFE or TEFLON). An example of the conductor may include a copper foil. In some embodiments, drive circuit board 302 may be a Printed Circuit Board (PCB) having integrated circuit wiring disposed on a dielectric substrate for generating and transmitting electrical drive signals 305. Due to its material and structural composition, the driver circuit board 302 may have a high coefficient of thermal expansion, particularly in the horizontal direction (i.e., the direction parallel to the plane of the board), but also a low thermal conductivity, particularly in the longitudinal direction (i.e., the direction perpendicular to the plane of the board), which is very low.

The driving circuit board 302 may transmit the electric driving signal 305 to the LD chip 301 through various electrical connection structures such as wire bonding (wire bonding), die bonding (die bonding), and the like. In some embodiments, the LD chip 301 is provided with a positive (P) electrode and a negative (N) electrode, and the driving circuit board 302 is also provided with a P terminal and an N terminal. The P terminal and the N terminal are connected to the P electrode and the N electrode, respectively, by wire bonding. Wire bonding may use a variety of conductor cables including, but not limited to, gold, copper, and aluminum, among others. In other embodiments, both the LD chip 301 and the driving circuit board may be bonded/soldered to the emission mount by die bonding using a conductive adhesive, and the emission mount is a conductive material. The N electrode of the LD chip 301 and the N terminal of the driving circuit board 302 are connected to a conductive emission mount by a conductive adhesive, thereby forming a negative interconnection between the LD chip 302 and the driving circuit board 302. While the P electrode of the LD chip 301 is still connected to the P terminal of the driving circuit board 302 by wire bonding, i.e., positive interconnection is formed.

The emission holder 303 is used to support the LD chip 301 and the driving circuit board 302 of the laser module. The launch cradle 303 may also be used to support any other components of the laser module. The emission stand 303 supporting the LD chip 301/driving circuit board 302 may include a case of direct support and indirect support through other intervening components. The emission support 303 may have any suitable shape capable of supporting the LD chip and the driving circuit board 302. In some embodiments, the emission cradle 303 may at least partially comprise a planar substrate or base. In further or alternative embodiments, the launch pad 303 may include a boss, a slot, or other retaining/aligning structure. In some embodiments, launch cradle 303, or at least a portion thereof, may be part of a housing of a lasing module or even a larger optical device (e.g., a laser sensor or lidar device) that includes a lasing module. The launch pad 303 may be integrally formed or may be formed from one or more sub-pads that are assembled by mechanical connections. For example, the LD chip 301 and the driving circuit board 302 may be respectively disposed on a first sub-mount and a second sub-mount, which are not integrally formed but are fixed together by mechanical connection means such as welding, riveting, snapping, locking, etc., and thus may be regarded as the emission mount 303 as a whole. The emitter support 303 may be made of a metallic material such as aluminum, gold, copper, etc. The heat conductivity of the emission support 303 may be high, for example, higher than the LD chip and the driving circuit board, and thus is suitable as a heat dissipating component. The thermal expansion coefficient of the emission mount 303 is relatively low, and may be lower than the driving circuit board 302, for example, but may be higher than the LD chip 301 in some cases. In addition, the transmitting bracket 303 is stronger in rigidity, and may be higher than the LD chip and the driving circuit board, for example.

Since the emission holder 303 has a high thermal conductivity and is suitable for a heat dissipation member, the LD chip can be placed on one side of the emission holder 303, so that heat generated by the LD chip can be conducted to the emission holder 303 and dissipated. Thereby forming a thermal conduction path 306 from the LD chip 301 to the emission mount 303. In some embodiments, the LD chip 301 may be placed directly on the emission support 303, i.e., without other components in between. It should be noted that the case where the LD chip 301 is directly placed on the emission mount 303 as referred to herein may include the case where the LD chip 301 is connected to the emission mount 303 by a conductive adhesive as described above, and may also include the case where a layer (generally having a small thickness) of a dielectric material is provided between the LD chip 301 and the emission mount 303 in order to improve electromagnetic compatibility. In other words, "directly placing" does not exclude that a thin layer (with respect to the size of the LD chip or the emission support) of material is provided between the LD chip 301 and the emission support 303. In some embodiments, the LD chip 301 may be placed indirectly on the launch support 303 via other intervening components. Other centering components may be any components capable of conducting heat, including various configurations of heat sinks, thermally conductive substrates, and the like. For example, as will be described later in detail in conjunction with fig. 4, the LD chip 301 may be provided on the side of the emission mount via a rigid heat conductive substrate. Whether "directly placed" or "indirectly placed", at least a part (most in many cases) of the heat generated by the LD chip 301 is eventually dissipated via the emission stand 303. Further, the heat conducting path 306 from the LD chip 301 to the emission stand 303 may not terminate at the emission stand 303, but may include an extension line of a wiring from the LD chip to the emission stand 303. This is because, if a heat conducting member is placed on the extension line, the heat conducted to the emission support 303 will continue to be conducted via the heat conducting member, which will also constitute a part of the heat conducting path.

The driving circuit board 302 is placed to be offset with respect to the heat conduction path 306 from the LD chip 301 to the emission stand 303. "offset" may mean that the thermally conductive via 306 is not routed to the driver circuit board 302, or that the driver circuit board 302 is spaced a distance from the thermally conductive via 306. In some embodiments, the LD chip 301 may be positioned on the same side of the emission support 303 as the driving circuit board 302 (as shown in fig. 3). In other embodiments, the LD chip 301 may be positioned on a different side of the emission stand 303 than the driving circuit board 302. For example, the LD chip 301 may be on the front side of the emission support 303, and the driving circuit board 302 may be on the back side of the emission support 303. In the case where the LD chip 301 and the driving circuit board 302 are located on the same side of the emission support, the LD chip 301 and the driving circuit board 302 are distributed at a distance (denoted by d) in a plane parallel to the same side, that is, the driving circuit board 302 and the LD chip 301 are not in contact.

Compared with the existing laser emission module structure, the heat conduction path from the LD chip to the emission support of the driving circuit board is removed, the heat dissipation path is shortened, and the problem that the driving circuit board is used as a heat dissipation bottleneck is relieved. Therefore, the LD chip can work at a lower temperature, so that the problems of power reduction, divergence angle change, service life shortening and the like caused by high temperature of the LD chip are avoided. Moreover, the driving circuit board is deviated from the heat conducting path, the influence of heat on the driving circuit board is reduced, the driving circuit board will be less likely to fail due to heat accumulation, and the alignment of the LD chip and optical devices possibly mounted on the emission bracket will also be less likely to be affected and temperature-induced stress changes will be less likely to be transmitted to the LD chip to affect the operation of the LD chip, thereby improving the stability of the optical path. In addition, compared with the common method that the LD chip is installed on the driving circuit board and then the driving circuit board is installed on the emission support in the existing laser emission module, the assembly process is simplified and the positioning precision is improved by placing the LD chip on the emission support without the driving circuit board.

In a further embodiment, in order to reduce the influence of stress variations on the LD chip, a rigid heat conducting substrate may be disposed between the emission support and the LD chip. Fig. 4 shows a schematic structural diagram of a laser emission module 400 according to an embodiment of the present disclosure. The laser emission module 400 is provided with a rigid heat conductive substrate 404 between the LD chip 401 and the emission support 403. The rigid thermally conductive substrate 404 may be at least partially a planar plate-like structure including a first side parallel to a mounting plane of the LD chip 401 and the emission mount 403 and a second side opposite to the first side. Specifically, the LD chip 401 is fixed to a first side of the rigid heat conductive substrate 404, and a second side of the rigid heat conductive substrate 404 is fixed to the emission support 403. The characteristics of the LD chip 401, the driving circuit board 402, the emission bracket 403, and the electric driving signal 405 are substantially the same as those of the LD chip 301, the driving circuit board 302, the emission bracket 303, and the electric driving signal 305 in fig. 3, which are not described herein again. The following mainly describes the differences from fig. 3.

On the one hand, the rigid heat conducting substrate 404 has good heat conductivity, and therefore does not affect the heat conduction of the LD chip 401 to the emission mount 403. The rigid heat conducting substrate will constitute a part of the heat conducting path 406, i.e. form a heat conducting path 406 from the LD chip 401 to the emission support 403 via the rigid heat conducting substrate 404. On the other hand, the rigid heat conducting substrate 404 has higher rigidity than the LD chip 401, and can resist the influence of the stress variation of other components caused by the temperature variation on the LD chip.

As in fig. 3, the driver circuit board 402 is also positioned offset from the thermal conduction path 406 in fig. 4. In some embodiments, the footprint (footprint) of the rigid thermally conductive substrate 404 is larger than the footprint of the LD chip 401. The driving circuit board 402 may be disposed on the same side or different side of the emission stand 403 as the LD chip 401. In a case where the driving circuit board 402 is on the same side of the emission support 403 as the LD chip 401 and the footprint of the rigid heat-conductive substrate 404 is larger than that of the LD chip 401, the driving circuit board 402 is spaced apart from the rigid heat-conductive substrate 404 by a distance (denoted as d') in a plane parallel to the same side.

In some embodiments, the rigid thermally conductive substrate 404 is substantially insulating. Providing the insulating rigid heat-conductive substrate 404 between the LD chip 401 and the emission mount 406 can improve electromagnetic compatibility problems such as static electricity, as compared to the case where the LD chip 301 is directly connected to the emission mount by a conductive adhesive or the case where the rigid heat-conductive substrate 404 is made of a conductive material in the laser emission module 300 of fig. 3. The rigid thermally conductive substrate 404 may be at least one of a ceramic substrate, an aluminum nitride substrate, or an aluminum oxide substrate.

In the laser emission module 400, in order for the driving circuit board 402 to be able to supply the electric driving signal 405 to the LD chip 401, various types of electrical connection structures may be formed between the driving circuit board 402 and the LD chip 401 using wire bonding or die bonding. For example, the LD chip 401 may be wire-bonded with the driving circuit board 402 to form a positive electrode interconnection and a negative electrode interconnection as described above in connection with fig. 3. Alternatively, the LD chip 401 may form a negative interconnection to the driving circuit board 402 via the electrically conductive rigid thermally conductive substrate 404 and the emission mount 403 with an electrically conductive adhesive between these devices, and form a positive interconnection to the driving circuit board 402 with wire bonding.

In some embodiments, the electrical connection structure between the driving circuit board 402 and the LD chip 401 may be formed with conductive traces on the rigid thermally conductive substrate 404 to transmit the electrical driving signal 405. Fig. 5 illustrates one exemplary implementation of laser transmitter module 400 of fig. 4 forming an electrical connection structure for transmitting electrical drive signal 405. The LD chip 401 is fixed to a rigid heat conductive substrate 404 by die bonding. On the one hand, the LD chip 401 and the rigid heat conductive substrate 404 are soldered/bonded by an electrically conductive bonding agent 405c (such as gold-tin eutectic solder, electrically conductive silver paste, or the like), thereby leading an electrode of one polarity (an N electrode, for example) of the LD chip 401 to the rigid heat conductive substrate 404. A first electrically conductive trace on the rigid thermally conductive substrate 404 extends the N electrode and is connected by wire bond 405d to an N terminal on the drive circuit board 402. On the other hand, the electrode of the other polarity (P electrode oppositely) of the LD chip is led to the rigid heat-conductive substrate 404 by wire bonding 405a, and a second electrically conductive trace on the rigid heat-conductive substrate 404 extends the P electrode and is connected to the P terminal on the drive circuit board 402 by wire bonding 405 b. Thus, the wire bonds 405a, the second conductive traces on the rigid thermally conductive substrate 404, and the wire bonds 405b form a positive interconnection between the LD chip 401 and the driving circuit board 402. The conductive bonding agent 405c for die bonding, the first conductive traces on the rigid heat conductive substrate 404, and the wire bonds 405d constitute negative interconnections between the LD chip 401 and the driving circuit board 402. At least a portion of each of the first and second electrically conductive traces may be located on a surface of the rigid thermally conductive substrate 404. Further, the first and second electrically conductive traces may be located on both sides of the rigid thermally conductive substrate 404 centered on the LD chip, respectively, and the driving circuit board is located around the both sides of the LD chip, so that there is a sufficient spacing distance between the positive and negative interconnections to prevent short circuit, and the wire bonding distance is as short as possible.

Returning to fig. 4, the ld chip 401 and the rigid heat conductive substrate 404, the rigid heat conductive substrate 404 and the emission bracket 403, and the driving circuit board 402 and the emission bracket 403 may be connected by soldering or bonding through various conductive/nonconductive adhesives. For example, the LD chip 401 may be soldered or bonded to the rigid heat conducting substrate 404 using gold-tin eutectic solder, conductive silver paste, or the like. The rigid thermally conductive substrate 404 may be bonded to the emitter support 403 using low temperature solder, electrically conductive silver paste, or the like. The driver circuit board 402 may be bonded to the emission support 403 using various organic glues. In order to improve the alignment accuracy when the respective components are connected, the following means may be adopted: the placement of alignment/positioning marks, the use of high precision placement machines, and/or the placement of positioning structures (e.g., bosses, recesses), etc.

In some embodiments, the laser emission module may further include beam shaping optics for beam shaping the probe laser emitted from the LD chip. In some embodiments, the beam shaping optics may shape the probing laser beam with a certain divergence angle emitted from the LD chip into collimated light or a beam with a certain divergence angle. In further or alternative embodiments, the beam shaping optics may also focus the probe laser beam. Beam shaping optics may include, but are not limited to: focusing and/or collimating optical lens(s); and/or a diaphragm. The beam shaping optics may also be supported by the emission support, as may the LD chip and the driver circuit board of the laser module. Because the LD chip and the beam shaping optical device are both supported by the emission bracket, and the driving circuit board which is easily affected by temperature and has volume change is removed from between the LD chip and the emission bracket, along with the temperature change, the displacements of the LD chip and the beam shaping optical device relative to the emission bracket can be mutually offset, thereby indirectly ensuring the continuous alignment of the LD chip and the beam shaping optical device and improving the stability of an optical path.

Fig. 6A and 6B show perspective and top views, respectively, of one non-limiting example structure in which the laser transmitter module 400 of fig. 4 further includes beam shaping optics. The LD chip 601, the driving circuit board 602, the emission mount 603, and the rigid heat-conductive substrate 604 correspond to the LD chip 301, the driving circuit board 302, the emission mount 303, and the rigid heat-conductive substrate 304 in fig. 4, respectively. In fig. 6A and 6B, an LD chip 601 is disposed on a rigid heat-conductive substrate 604, and a drive circuit board 602 is disposed partially around the rigid heat-conductive substrate 604. The LD chip 601 is an edge-emitting laser whose laser emission direction is parallel to the substrate surface of the laser diode. In the example of fig. 6A and 6B, the beam shaping optics may include two sets of optical lenses 608 and apertures 609. As a non-limiting example, two sets of optical lenses 608 may be used to achieve fast axis collimation and slow axis collimation, respectively; the diaphragm 609 can trim the edge of a light spot of the laser beam to filter stray light. The LD chip 601, the driving circuit board 602, the rigid heat-conductive substrate 604, the optical lens 608, and the stop 609 are all supported by the emission support 603. Since the driving circuit board 602 is no longer located between the LD chip 601 and the emission support 603, the relative position of the LD chip with respect to the emission support 603 will not change due to thermal expansion and contraction, and the displacements experienced by the LD chip 601, the optical lens 608, and the diaphragm 609 can cancel each other out, thereby ensuring the stability of the optical path.

To assist in the alignment of the LD chip with the optics, various positioning/limiting/aligning structures may be provided on the emission support 603. For example, the LD chip 601, the driving circuit board 602, and the rigid heat conductive substrate 604 may be positioned by a groove or a boss on the emission mount 603. The optical lens 608 and the stop 609 may be positioned by a V-shaped retaining groove.

In one or more embodiments, the LD chip 601 and the rigid thermally conductive substrate 604 are fixed to the boss of the emission mount 603. As described above, the fixing may be performed by bonding means such as low-temperature solder or conductive silver paste. In the fixing process, the edge of the rigid heat conducting substrate 604 can be matched with the side edge of the boss, so that the position and the angle of the LD chip 601 on the rigid heat conducting substrate 604 relative to the emission support 603 are ensured, and the direction and the angle of the light-emitting optical axis of the LD chip are further ensured. After the LD chip 601 and the rigid heat conducting substrate 604 are fixed, wire bonding between the LD chip 601 and the driving circuit board 602 is performed, as described above with reference to fig. 3 and 4. The height and position of the bumps can be controlled to reduce the wire bonding length required for wire bonding between the LD chip 601 (and the rigid heat-conducting substrate 604) and the driving circuit board 602, thereby reducing the influence of the wire bonding length on the pulse width of the light source of the LD chip. The height of the boss may be designed such that: after the rigid heat-conductive substrate 604 is fixed to the boss of the emission bracket 603, the rigid heat-conductive substrate 604 conforms in height to the upper surface of the driving circuit board 602. Thus, the wire bond length in the vertical direction is substantially eliminated, and the wire bond substantially spans the rigid heat-conducting substrate 604 and the driving circuit board 602 only in the horizontal direction. After the routing length in the vertical direction is reduced, the routing length in the horizontal direction can be further reduced. The driver board 602 may be positioned on the launch support 603 by a number of pins on the launch support 603. When the launch bracket 603 is machined, form and position tolerances between the first side surface and the second side surface, perpendicular to each other, of the pin and the boss for fixing the driving circuit board 602 are managed. For example, the boss may be rectangular in shape, with the first and second sides being the long and wide sides of the rectangle. Furthermore, a groove can be reserved at the position of the driving circuit board 602 corresponding to the rigid heat-conducting substrate 604 and the LD chip 601, and a gap between the groove and the boss can be calculated and analyzed to avoid size interference between the driving circuit board 602 and the boss under the condition of an actual material extreme value, so that the correspondence between the driving circuit board and the routing positions of the rigid heat-conducting substrate 604 and the LD chip 601 is ensured, the routing length is reduced, and the influence of the routing length on the light source pulse width of the LD chip is reduced.

Although fig. 6A and 6B illustrate the alignment of an edge-emitting laser type laser module with optics, one of ordinary skill in the art will recognize that the techniques of the present disclosure may also be applied to a surface-emitting laser type laser module. It is only necessary here to have the first part of the transmitter holder supporting the laser module orthogonal to the second part of the transmitter holder supporting the beam shaping optics, then the laser beam emitted in a surface emitting manner from the LD chip in the laser module will exit orthogonal to the first part of the transmitter holder so that it is parallel to the second part of the transmitter holder and to the individual optics supported on the second part, so that alignment is still possible. In the laser emission module, the driving circuit board deviates from a heat conduction path from the surface-emitting type LD chip to the first part of the emission support by applying the technology of the present disclosure, so that the heat dissipation effect can be still improved, and the working stability of the LD chip can be improved.

Fig. 7 shows a flow diagram of a method 700 for manufacturing a laser emitting module according to an embodiment of the present disclosure. The method 700 may be used to manufacture the laser emitting module 300, the laser emitting module 400, and any other laser emitting module according to embodiments of the present disclosure as previously described. Fig. 7 mainly relates to the flow steps of the method, and for specific features of each component involved in the method 700, reference may be made to the description above with reference to fig. 3 to 6, which are not repeated herein.

In step 702, an LD chip for emitting a detection laser in response to an electric drive signal is fixed to an emission mount. Fixing the LD chip to the emission stand may include placing the LD chip directly on the emission stand, or may also include placing the LD chip indirectly on the emission stand via other intervening components. The LD chip may be fixed to the emission mount by means of soldering or bonding or the like by various conductive/nonconductive adhesives. The conductive bonding agent may include, for example, gold-tin eutectic solder, conductive silver paste, or the like. The non-conductive bonding agent may be, for example, an organic glue. In order to help the LD chip be accurately positioned at a proper position on the emission support to facilitate subsequent alignment with other optical devices, alignment/positioning marks or positioning mechanisms (e.g., bosses, grooves, etc.) may also be provided on the emission support. The LD chip may be mounted to the emission mount using a high precision mounter.

In step 704, a driving circuit board that generates an electric driving signal for the LD chip is fixed to the emission mount, and the driving circuit board is placed to be offset with respect to a heat conduction path through which heat generated by the LD chip is conducted from the LD chip to the emission mount. Securing the driver circuit board to the launch pad may include placing the driver circuit board directly on the launch pad, or may include placing the driver circuit board indirectly on the launch pad via other intervening components. The driver circuit board may be fixed to the emission cradle by soldering or bonding or the like by various conductive/nonconductive adhesives. The conductive bonding agent may include, for example, gold-tin eutectic solder, conductive silver paste, or the like. The non-conductive bonding agent may be, for example, an organic glue. To assist in accurately positioning the driver circuit board in the proper location on the launch support to facilitate subsequent alignment with other optical devices, the launch support may also be provided with alignment/positioning marks or positioning mechanisms (e.g., bosses, recesses, etc.). The driver circuit board may be mounted to the emitter support using a high precision placement machine. In some embodiments, the driving circuit board may be disposed on the same side of the emission support as the LD chip. At this time, the LD chip may be distributed at a distance from the driving circuit board in a plane parallel to the same side, that is, the driving circuit board is not in contact with the LD chip.

In step 706, an electrical connection structure to the driving circuit board to the LD chip is formed to transmit the electrical driving signal. The electrical connection structure may include wire bonding directly from the driving circuit board to the LD chip. Wire bonding may use a variety of conductor cables including, but not limited to, gold, copper, and aluminum, among others. The electrical connection structure may also include an indirect path where the LD chip and the driving circuit board are both connected to the conductive emitter support in a die-bonding manner. The electrical connection structure may include a positive interconnection and a negative interconnection. The positive and negative interconnections may be implemented using the same or different bonding means (wire bonding, die bonding, or a combination thereof).

In some embodiments, the laser emission module may further include a rigid heat conductive substrate between the LD chip and the emission mount. The rigid thermally conductive substrate may be, for example, the rigid thermally conductive substrate 404 depicted in fig. 4. Accordingly, step 702 may further include: the LD chip is fixed to a first side of the rigid heat conductive substrate, and a second side of the rigid heat conductive substrate opposite to the first side is fixed to the emission mount. The thermally conductive via now includes a path from the LD chip to the emitter support via the rigid thermally conductive substrate. The driver circuit board is still offset relative to the thermally conductive path while the driver circuit board is secured to the launch pad in step 704. Under the condition that the floor area of the rigid heat conduction substrate is larger than that of the LD chip, the driving circuit board is not in contact with the rigid heat conduction substrate and is away from the rigid heat conduction substrate by a certain distance. Accordingly, step 706 specifically includes: a first electrical connection structure is formed from the driving circuit board to the rigid heat conductive substrate, and a second electrical connection structure is formed from the rigid heat conductive substrate to the LD chip. In some embodiments, the first and second electrically conductive traces may be formed on a rigid thermally conductive substrate, and accordingly the first electrical connection structure comprises the first electrically conductive trace and the second electrical connection structure comprises the second electrically conductive trace. The first and second electrically conductive traces may be at least partially on a surface of the rigid thermally conductive substrate. In some embodiments, the first conductive trace may be connected to the P-electrode of the LD chip via a wire bond from the P-terminal of the driving circuit board, thereby forming the first electrical connection structure as a positive electrode interconnection; and may be connected from the N terminal of the driving circuit board to a second conductive trace connected to the N electrode of the LD chip via a wire bond, thereby forming a second electrical connection structure as a negative interconnection.

Fig. 8 shows a laser radar apparatus 800 according to an embodiment of the present disclosure, which employs a laser emitting module according to an embodiment of the present disclosure as a light source. Lidar device 800 may include a laser transmit module 802, a scanner 804, a laser receive module 806, and a controller 808.

The laser emitting module 802 emits a probe laser beam for scanning the target object 120. The laser emission module 802 may be the laser emission module 300, the laser emission module 400, and any other laser emission module according to an embodiment of the present disclosure as previously described. Lidar device 800 may include one or more such lasing modules 802.

The scanner 804 is used to deflect the direction of the probing laser beam from the laser emission module 802 to scan the target object 820, enabling a wider emission field of view or scanning field of view. The scanner 804 may include any number of optical mirrors driven by any number of drivers. For example, the scanner 804 may include a plane mirror, a prism, a mechanical galvanometer, a polarizing grating, an Optical Phased Array (OPA), a micro-electromechanical system (MEMS) galvanometer. For MEMS galvanometers, the mirror surface rotates or translates in one or two dimensions under electrostatic/piezoelectric/electromagnetic actuation. Driven by the driver, the scanner 804 directs the light beam from the laser emission module 802 to various locations within the field of view to effect a scan of the field of view.

After the light beam is reflected from the target object 820, a part of the reflected light returns to the laser radar apparatus 800 and is received by the laser receiving module 806. The laser receiving module 806 receives and detects a portion of the reflected light from the target object 820 and generates a corresponding electrical signal. The laser receive module 806 may include a receive unit and associated receive circuitry. Each receiving circuit may be for processing an output electrical signal of a respective receiving unit. The receiving unit includes various forms of photodetectors or one-or two-dimensional arrays of photodetectors, and accordingly, the receiving circuit may be a circuit or an array of circuits. The photodetector measures the power, phase or time characteristics of the reflected light and generates a corresponding current output. The photodetector may be an avalanche diode (APD), a Single Photon Avalanche Diode (SPAD), a PN type photodiode, or a PIN type photodiode.

The controller 808 is communicatively coupled to one or more of the laser emitting module 802, the scanner 804, and the laser receiving module 806. The controller 808 may control whether and when the laser emission module 802 emits a light beam. The controller 808 may control the scanner 804 to scan the light beam to a specific location. The controller 808 may process and analyze the electrical signals output by the laser receive module 806 to ultimately determine the position, velocity, etc., characteristics of the target object 820. The controller 808 may include an Integrated Circuit (IC), an Application Specific Integrated Circuit (ASIC), a microchip, a microcontroller, a central processing unit, a Graphics Processing Unit (GPU), a Digital Signal Processor (DSP), a Field Programmable Gate Array (FPGA), or other circuitry suitable for executing instructions or implementing logical operations. The instructions executed by the controller 808 may be preloaded into an integrated or separate memory (not shown). The memory may store configuration data or commands for the laser transmit module 802, the scanner 804, or the laser receive module 806. The memory may also store the electric signal output from the laser receiving module 806 or an analysis result based on the output electric signal. The memory may include Random Access Memory (RAM), read Only Memory (ROM), hard disk, optical disk, magnetic disk, flash memory or other volatile or non-volatile memory, etc. The controller 808 may include single or multiple processing circuits. In the case of multiple processing circuits, the processing circuits may have the same or different configurations, and may interact or cooperate electrically, magnetically, optically, acoustically, mechanically, etc.

In one or more embodiments, lidar device 800 may also include a transmit lens 810. The transmit lens 810 may be used to expand the beam emitted by the laser transmit module 802 and steered by the scanner 804. The emission lens 810 may include a Diffractive Optical Element (DOE) for shaping, separating, or diffusing the light beam. The transmit lens 810 may be present alone or may be integrated into other components (e.g., the scanner 804 or the laser emitting module 802). The position of the emission lens 810 in the emission optical path from the light source to the target object is not limited to that shown in fig. 8, but may be changed to other positions. For example, the emitting lens may be disposed between the laser emitting module 802 and the scanner 804 such that the light beam emitted by the light source 802 is first expanded by the emitting lens and then deflected by the scanner.

In one or more embodiments, lidar device 800 may also include a receive lens 812. The receiving lens 812 is located before the laser receiving module 806 on a receiving path of the emitted light from the target object 820 to the laser receiving module 806. The receive lens 812 may include an imaging system lens such that the focal point of the reflected beam is in front of or behind or just above the detection surface of the photodetector or photodetector array. In some cases, instead of being a separate component, receive lens 812 may also be integrated into laser receive module 806.

In one or more embodiments, lidar device 100 may also include a housing 814 that encloses one or more of the aforementioned components for protection. In some embodiments, the housing 814 is an opaque material, and the housing 814 may be provided with a transparent region or window 816 to allow the transmitted or reflected light beam to pass therethrough. In other embodiments, housing 814 is itself a transparent material, thereby allowing the emitted or reflected light beam to pass through from any location. In some embodiments, the launch cradle in the laser launch module 802 may be part of the housing 814.

Lidar device 800 may include a coaxial optical transceiver system or a non-coaxial optical transceiver system. The coaxial optical transceiver system means that a transmission path from the laser emission module 802 to the target object 820 and a reception path from the target object 820 to the laser reception module 806 are at least partially overlapped. For example, unlike that shown in fig. 8, the reflected beam may reach the laser receiving module 806 after passing back through the scanner 804. The non-coaxial optical transceiving system means that there is no overlapping portion between a transmission path from the laser transmission module 802 to the target object 820 and a reception path from the target object 820 to the laser reception module 806. For example, as shown in FIG. 8, the reflected beam no longer reaches the laser receiving module 806 via the scanner 804.

In the present disclosure, the steps described in the flowcharts include not only the processing performed in time series in the described order but also the processing performed in parallel or individually without necessarily being performed in time series. Further, even in the steps processed in time series, the order may be changed as appropriate.

The terms "center," "upper," "lower," "inner," "outer," and the like in this disclosure indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing embodiments of the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated, and therefore, should not be construed as limiting the embodiments of the present invention.

The terms "comprises," "comprising," or any other variation thereof, in this disclosure are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Furthermore, the technical terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. References to a "first" component do not necessarily require the provision of a "second" component. Furthermore, unless explicitly indicated otherwise, "first" or "second" components do not imply that the referenced components are limited to a particular order.

In the description of the present disclosure, "plurality" means two or more unless specifically limited otherwise. The term "or" means an inclusive "or" rather than an exclusive "or". The term "based on" means "based at least in part on".

In the description of the present disclosure, unless otherwise specifically limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrated; mechanical connection or electrical connection is also possible; either directly or indirectly through intervening media, either internally or in any other relationship. Specific meanings of the above terms in the embodiments of the present invention can be understood by those of ordinary skill in the art according to specific situations.

In the description of the present disclosure, unless otherwise explicitly specified or limited, a first feature "on" or "under" a second feature may be directly contacting the first and second features, or the first and second features may be indirectly contacting each other through intervening media.

Finally, it should be noted that: while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention, and they should be construed as being included in the following claims and description. In particular, the technical features mentioned in the embodiments can be combined in any way as long as there is no structural conflict. It is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A laser transmitter module, comprising:

a laser module comprising:

a Laser Diode (LD) chip configured to emit a detection laser in response to an electric drive signal; and

a driving circuit board configured to provide the electric driving signal to the LD chip; and

an emission support supporting the LD chip and the driving circuit board of the laser module,

wherein heat generated by the LD chip is conducted via the emission mount, and the driving circuit board is placed to deviate from a heat conduction path from the LD chip to the emission mount.

2. The laser emitting module of claim 1, further comprising:

a rigid thermally conductive substrate, wherein the LD chip is fixed to a first side of the rigid thermally conductive substrate, a second side of the rigid thermally conductive substrate opposite the first side is fixed to the emission mount,

wherein the driving circuit board is placed to deviate from a heat conduction path from the LD chip to the emission support via the rigid heat conduction substrate.

3. The laser emitting module of claim 2, wherein the rigid thermally conductive substrate is at least one of a ceramic substrate, an aluminum nitride substrate, or an aluminum oxide substrate.

4. The laser emitting module of claim 2, wherein the rigid thermally conductive substrate is substantially insulating.

5. The laser emitting module of any of claims 2-4, wherein the LD chip receives electrical drive signals from the drive circuit board via electrically conductive traces on the rigid thermally conductive substrate.

6. The laser emitting module of claim 1, wherein the LD chip and the driving circuit board are positioned on a same side of the emitting mount.

7. The laser emitting module of claim 6, wherein the driving circuit board and the LD chip are distributed at a distance in a plane parallel to the same side.

8. The laser emitting module of claim 1, wherein the emitting mount is made of a metallic material.

9. The laser emitting module of claim 1, wherein the driving circuit board comprises a resin material.

10. The laser emitting module of claim 1, wherein the driving circuit board is electrically connected with the LD chip by wire bonding to provide the electric driving signal to the LD chip.

11. The laser emitting module of claim 1, further comprising:

a beam shaping optical device that beam-shapes the detection laser light emitted by the LD chip,

wherein the emission mount further supports the beam shaping optics.

12. A lidar device characterized by comprising:

the laser emitting module according to any one of claims 1-11;

a scanner configured to direct the detection laser light from the laser emission module to scan a target object;

a laser receiving module configured to detect detection laser light reflected by the target object to output an electrical detection signal; and

a controller configured to communicatively couple and control the laser emitting module, the scanner, and the laser receiving module.