The present application claims the benefit of priority to Chinese Patent Application No. 202211360853.7, filed Oct. 31, 2022, and Chinese Patent Application No. 202310269943.3, filed Mar. 15, 2023, both of which are hereby incorporated by reference in their entireties.
This application relates to the technical field of laser ranging technology, and in particular, to a laser emission module and a laser ranging device, an emission packaging module, an emission module, and a Light Detection and Ranging (LiDAR).
The laser rangefinder is a radar system that uses lasers to detect the position, speed, and other characteristics of a target object. Its working principle is to first emit a laser for detection towards the target object, then receive the echo laser reflected back from the target object. After processing the received echo laser signal, information about the target object, such as distance, direction, height, speed, attitude, and even shape parameters, can be obtained.
In the related technology, a laser rangefinder typically uses a laser emission circuit 100 to emit a laser. As shown in
How to reduce the assembly size of a laser emission circuit 100 has become a problem that needs to be solved by technicians in this field.
The Vertical-Cavity Surface-Emitting Laser (VCSEL) is a type of semiconductor, which emits laser vertically from its top surface and plays a significant role in areas such as laser ranging and space laser communication. The traditional packaging or assembly method for a VCSEL is to directly use the Chips on Board (COB) process on the product's Printed Circuit Board (PCB). The COB process refers to the technique of adhering bare chips to the interconnect substrate using conductive or non-conductive adhesive. However, the COB process generally requires a large number of wire bonds, and for many VCSEL emission modules, densely packed bonding pads are needed, which is difficult to achieve a dense spacing of about 50 um in the manufacturing process. At the same time, excessive wire bonding can also reduce the overall manufacturing efficiency, and if a VCSEL is scrapped, it will lead to the scrapping of the entire product's PCB.
Embodiment of this application provides a laser emission module and a laser ranging device.
In the first aspect, an embodiment of this application provides a laser emission module; the laser emission module includes: an emission substrate, comprises a first board surface; a light emitting chip, assembled on the first board surface, internally integrates a laser array; the laser array comprises m*n lasers, where m and n are respectively the number of rows and the number of columns of lasers comprised in the laser array, both m and n are positive integers, and at least one of m and n is greater than 1; in the laser array, anodes of the lasers located in the same row are electrically connected and lead out to a common anode end, cathodes of the lasers located in the same column are electrically connected and lead out to a common cathode end; at least one anode drive chip, assembled on the emission substrate, internally integrates m anode drive circuits; the m anode drive circuits are respectively electrically connected to the m common anode ends in a one-to-one correspondence; at least one cathode drive chip, assembled on the emission substrate, internally integrates n cathode drive circuits; the n cathode drive circuits are electrically connected to the n common cathode ends in a one-to-one correspondence.
In an embodiment, the laser emission module further comprises a package protective cover and a light transmission cover plate; the package protective cover is located on the emission substrate, forming a containment space with the emission substrate, the containment space is used to accommodate the elements assembled on the emission substrate; wherein the package protective cover corresponding to the light emitting chip, has a light transmitting opening, the light transmission cover plate is placed over the light transmitting opening, which is used for the laser emitted by the light emitting chip to out of the laser emission module.
In an embodiment, the laser emission module is packaged using Ball Grid Array (BGA) technology, Land Grid Array (LGA) technology, or Quad Flat No-leads (QFN) packaging technology.
In a second aspect, embodiment of this application provides a laser ranging device, which includes the laser emission module described in any of the above items.
The laser emission module 300 provided in this application achieves chip integration of the anode drive circuit 131 and the cathode drive circuit 140 and assembles the integrated anode drive chip 330 and cathode drive chip 340 onto the emission substrate 350. This can reduce the area occupied by the anode drive circuit 131 and the cathode drive circuit 140 on the emission substrate 350, and thus, by reducing the area of the emission substrate 350, the size of the laser emission module 300 can be reduced, facilitating the miniaturization design of the laser ranging device.
This application also provides an emission packaging module, emission module, and LiDAR, which can reduce the difficulty of packaging multiple VCSELs onto a circuit board and improve reliability.
In the third aspect, this application provides an emission packaging module, include:
In an embodiment, the drive module includes at least one first high-side drive chip and at least one first low-side drive chip.
In an embodiment, the first high-side drive chip and the first low-side drive chip drive at least one group of vertical cavity surface emitting lasers to emit light by selecting at least one group from the at least two groups of vertical cavity surface emitting lasers.
In an embodiment, the at least two groups of vertical cavity surface emitting lasers are an array of vertical cavity surface emitting lasers.
In an embodiment, the drive module also includes a second high-side drive chip, the first high-side drive chip and the second high-side drive chip are respectively located on the two sides opposite to the vertical cavity surface emitting laser array and are used to drive different groups of vertical cavity surface emitting lasers in the vertical cavity surface emitting laser array.
In an embodiment, the at least two groups of vertical cavity surface emitting lasers are an array of vertical cavity surface emitting lasers.
The drive module also includes a second low-side drive chip, the first low-side drive chip and the second low-side drive chip are respectively located on the two sides opposite to the vertical cavity surface emitting laser array, and are used to drive different groups of vertical cavity surface emitting lasers in the vertical cavity surface emitting laser array.
In an embodiment, the at least one capacitor also includes at least one bootstrap capacitor, used for opening or maintaining the drive state of the first high-side drive chip.
In an embodiment, the at least one capacitor also includes at least one decoupling capacitor corresponding to the first high-side drive chip and/or the first low-side drive chip, the first high-side drive chip and/or the first low-side drive chip are connected to the ground through the corresponding decoupling capacitor.
In an embodiment, the pins of the first high-side driver chip and/or the first low-side driver chip are arranged adjacent to their corresponding decoupling capacitors.
In an embodiment, the energy storage capacitor is arranged adjacent to the at least two sets of vertical cavity surface emitting lasers.
In an embodiment, the at least two sets of vertical cavity surface emitting lasers are mounted to the substrate through COB (Chip On Board) technology, and are wire bonded to the solder pads on the substrate.
In an embodiment, the drive module is pre-packaged into a ball grid array packaging form through a chip-level packaging process.
In an embodiment, the drive module is mounted to the substrate via COB technology and is wire-bonded to the pads on the substrate; or the drive module is mounted to the substrate through an inverted chip process.
In an embodiment, the at least one capacitor is mounted to the substrate using surface mounting technology.
In an embodiment, the light transmissible cover plate includes a cover plate area, and a light window area located on the light path of the emitted lasers from the at least two groups of vertical cavity surface emitting lasers.
In an embodiment, the thermal expansion coefficient of the cover plate area is in a range of [12×10−6/deg, 15×10−6/deg], and the thermal expansion coefficient of the substrate is in a range of [10×10−6/deg, 12×10−6/deg].
In an embodiment, the cover plate area is attached to the substrate by a first adhesive, and is attached to the light window area by a second adhesive.
In an embodiment, the first adhesive is a single-component thermosetting epoxy resin, and the second adhesive is a single-component thermosetting silicone rubber.
In an embodiment, an inert gas is filled in the airtight space.
In an embodiment, the substrate is a BT resin-based copper clad board; and/or, the area where the substrate contacts with at least two groups of vertical cavity surface emitting lasers is filled with a metal.
In a fourth aspect, this application discloses an emission module, which includes the aforementioned emission packaging module and a circuit board; a power supply and charging circuit are also set up on the circuit board; the circuit board is electrically connected to the emission packaging module.
In a fifth aspect, this application provides a LiDAR which comprises any one of the aforementioned emission packaging module.
In an embodiment, the LiDAR is a solid-state LiDAR.
In embodiment of this application, by locally packaging and integrating at least two groups of VCSELs and their driving modules and energy storage capacitors in the emission module into an emission packaging module, the packaged emission packaging module can be mounted on the circuit board during assembly. Compared with the direct mounting of multiple VCSELs and their driving modules and energy storage capacitors on the circuit board in the existing technology, once a scrapped VCSEL appears, it will cause the entire product's circuit board to be scrapped. Embodiment of this application can better pre-screen the emission packaging module, achieving higher yield control. Embodiment of this application can also reduce the process difficulty. In existing products, it is often required that each VCSEL is precisely aligned and mounted on the circuit board. In this application, by pre-packaging to form an emission packaging module, the difficulty of packaging each VCSEL onto the circuit board can be reduced. In addition, each VCSEL and its energy storage capacitor and driving module are packaged in the emission packaging module, which can reduce the parasitic parameters in the control drive circuit. Moreover, by integrating the key device modules in the emission module and overall packaging, this form can ensure the consistency and stability of multi-channel transmission devices, and the airtight packaging structure ensures the stability of the internal environment, thereby improving the reliability of the core power devices and driving devices and enhancing the overall reliability of the emission module.
To describe the technical solutions in the embodiments of this application more clearly, the following briefly describes the accompanying drawings required for describing the embodiments. Apparently, the accompanying drawings in the following description show merely some embodiments of this application, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.
To make objectives, technical solutions and advantages of the present application clearer, embodiments of the present application are described in further detail below with reference to the drawings. It should be understood that the embodiments described here are only used to explain this application and are not intended to limit this application. It should be noted that when a component is referred to as being “assembled on” or “assembled to” or “set on” or “set at” another component, it can be directly on the other component or indirectly on the other component through other components. When a component is referred to as being “connected to” another component or “connected with” another component, it can be directly connected to the other component or indirectly connected to the other component through other components. It should also be noted that the terms “row”, “column”, etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, are only relative concepts or are referenced to the normal use state of the product, for the purpose of facilitating the description of this application and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application. In addition, the terms “first”, “second”, “third”, “fourth” are only used for descriptive purposes, and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as “first”, “second”, “third”, “fourth” can explicitly or implicitly include one or more of such features.
Furthermore, in the description of this application, unless otherwise specified, “multiple” refers to two or more. “and/or” describes the relationship between associated objects, indicating that there can be three relationships. For example, A and/or B can mean: A exists alone, A and B exist simultaneously, or B exists alone. The character “/” generally indicates that the associated objects before and after are in an “or” relationship. Unless otherwise defined, all technical and scientific terms used in this document have the same meaning as commonly understood by technical person in the field of this application. The terms used in this specification are only for the purpose of describing embodiments, not intended to limit this application. The term “and/or” used in this document includes any and all combinations of one or more related items listed.
Referring to
How to reduce the assembly size of the laser emission circuit 100 has become a problem that needs to be solved in this field. In order to solve the technical problem of using discrete electronic components to assemble the laser emission circuit 100, which leads to a larger assembly size of the laser emission circuit 100, as shown in
Referring to
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Further, m anode drive circuits 131 and n cathode drive circuits 140 are combined to form m*n emission drive channels P1*1˜P1*n, Pm*1˜ Pm*n, where the emission drive channel Px*y includes the xth anode drive circuit 131 and the yth cathode drive circuit 140. The xth anode drive circuit 131 is the anode drive circuit 131 connected to the xth common anode end 311a, and the yth cathode drive circuit 140 is the cathode drive circuit 140 connected to the yth common cathode end 311b. x and y are positive integers, and 11 (the same applies below). m common anode ends 311a and n common cathode ends 311b are combined to form m*n emission drive end combinations G1*1˜G1*n, Gm*1˜Gm*n, where the emission drive end combination Gx*y includes the xth common anode end and the yth common cathode end. The xth common anode end 311a is the common anode end 311a led out from the xth row of lasers 311, and the yth common cathode end 311b is the common cathode end 311b led out from the yth row of lasers 311.
In this embodiment, m*n emission drive channels P1*1˜P1*n, Pm*1˜ Pm*n are sequentially activated according to a preset timing sequence to receive current IL. The electrical energy stored in the anode energy storage component 132 is sequentially applied as a forward bias voltage between the common anode end 311a and the common cathode end 311b included in the m*n emission drive end combinations G1*1˜G1*n, Gm*1˜Gm*n. This in turn sequentially applies a forward bias voltage between the anode and cathode of the m*n lasers 311, driving the m*n lasers 311 to emit light in sequence according to the preset timing sequence, so that the emitted laser light from the m*n lasers 311 scans the detection area. For example, when the emission drive channel Px*y is activated, the emission drive channel Px*y uses the electrical energy stored in the anode energy storage component 132 to apply a forward bias voltage to the laser 311 located at position (x, y), that is, the laser 311 in the xth row and yth column, to drive the laser 311 at position (x, y) to emit light.
In an embodiment, the term “preset timing sequence” refers to the activate order preset by the control part. m*n emission drive channels P1*1˜P1*n, Pm*1˜ Pm*n drive m*n lasers 311 to emit laser light in accordance with the preset timing sequence. This could involve first driving the laser 311 located at the (1, 1) position to emit light after it is activated, then driving the laser 311 located at the (1, 2) position to emit light after it is activated . . . until the laser 311 located at the (1, n) position is driven to emit light after it is activated. Then, the process begins with driving the laser 311 located at the (2, 1) position to emit light after it is activated, then driving the laser 311 located at the (2, 2) position to emit light after it is activated . . . until the laser 311 located at the (2, n) position is driven to emit light after it is activated . . . until the laser 311 located at the (m, n) position is driven to emit light after it is activated.
In an embodiment, the activation of m*n emission drive channels P1*1˜P1*n, Pm*1˜Pm*n includes two stages: an energy conversion stage and an energy release stage. The following will take the emission drive channel Px*y as an example to introduce the two stages during the activation of an emission drive channel.
Energy conversion stage: The xth anode drive circuit 131 included in the emission drive channel Px*y is turned on in the direction of the current towards the xth anode energy storage component 132, and the xth anode drive circuit 131 uses the received current IL to charge the xth anode energy storage component 132; where, the xth anode energy storage component 132 is the anode energy storage component 132 connected to the xth anode drive circuit 131.
Energy release stage: after the energy conversion stage, the yth cathode drive circuit 140 included in the emission drive channel Px*y is turned on in the direction from the xth common cathode end 311b to the ground GND. The xth anode energy storage component 132 uses the stored electrical energy to form a forward bias voltage between the xth common anode end 311a and the yth common cathode end 311b included in the emission drive end combination Gx*y. This forward bias voltage drives the laser 311 located at the xth row and yth column to emit light.
The laser emission module 300 achieves chip integration of the anode drive circuit 131 and the cathode drive circuit 140 and assembles the anode drive chip 330 and the cathode drive chip 340, which are obtained through the chip integration, on the emission substrate 350. This can reduce the area occupied by the anode drive circuit 131 and the cathode drive circuit 140 on the emission substrate 350, and thus, by reducing the area of the emission substrate 350, the size of the laser emission module 300 can be reduced, facilitating the miniaturization design of the laser ranging device.
Further, compared to the related technology that uses m*n discrete lasers 311 to form a laser array LDm*n, the laser emission module 300 provided by embodiments of this application integrates the laser array LDm*n through a light emitting chip 310. This can reduce the area occupied by the laser array LDm*n on the emission substrate 350, facilitating the reduction of the area of the emission substrate 350, and thereby reducing the assembly size of the laser emission module 300.
In an embodiment, the light emitting chip 310 uses a VSCEL (Vertical-Cavity Surface-Emitting Laser) array chip.
As shown in
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As shown in
Further, the surface 331 of the anode drive chip 330 is also equipped with a charging bonding point (not shown in the figure), which is electrically connected to the other end of the m anode drive circuits 131 integrated in the anode drive chip 330, for receiving current IL. The surface 341 of the cathode drive chip 340 is also equipped with a grounding bonding point (not shown in the figure), which is electrically connected to the other end of the n cathode drive circuits 140 integrated in the cathode drive chip 340, for grounding to GND.
Compared to the related technology, when assembling an anode drive circuit 131 and a cathode drive circuit 140 on a circuit board using discrete electronic components, each discrete electronic component needs to be first bound to the soldering points on the circuit board, and then to be electrically connected through the soldering points on the circuit board. This results in a large number of soldering points on the circuit board, and a larger circuit board area. The laser emission module 300 provided in embodiments of this application integrates the anode drive circuit 131 and the cathode drive circuit 140 into a chip, and then electrically connects to other electronic devices through bonding wires, reducing the number of soldering points on the emission substrate 350. This can reduce the area of the emission substrate 350, thereby reducing the assembly size of the laser emission module 300.
The laser emission module 300 provided in embodiment of this application is directly connected by bonding wires between the anode drive chip 330 and the anode energy storage component 132, as well as between the anode energy storage component 132 and the light emitting chip 310. This facilitates the shortening of the circuit length from the anode drive circuit 131 to the anode energy storage component 132 and from the anode energy storage component 132 to the common anode end 311a, reduce the link impedance, thereby reducing energy loss on the circuit and improving the light emitting power and light emitting efficiency.
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The m1 anode energy storage components 132 corresponding to the first anode drive chip 331 are arranged between the first anode drive chip 331 and the first side edge 4113a and are bonded and connected to the m1 anode drive bonding points 331a on the first anode drive chip 331 through m1 first bonding wires 151, to achieve a one-to-one electrical connection between the m1 anode energy storage components 132 and the m1 anode drive circuits 131. The m1 anode energy storage components 132 corresponding to the first anode drive chip 331 are also bonded and connected to the m1 common anode end bonding points 411a set on the first side edge 4113a through m1 second bonding wires 152, to achieve one-to-one electrical connection between the m1 anode energy storage components 132 and the m1 anode drive circuits 131. The m2 anode energy storage components 132 corresponding to the second anode drive chip 332 are arranged between the second anode drive chip 332 and the second side edge 4113b and are bonded and connected to the m2 anode drive bonding points 331a on the second anode drive chip 332 through m2 first bonding wires 151, to achieve one-to-one electrical connection between the m2 anode energy storage components 132 and the m2 anode drive circuits 131. The m2 anode energy storage components 132 corresponding to the second anode drive chip 332 are also bonded and connected to the m2 common anode end bonding points 411a located on the second side edge 4113b of the light emitting chip 310 through m2 second bonding wires 152, to achieve a one-to-one electrical connection between the m2 anode energy storage components 132 and the m2 anode drive circuits 131.
Further, the first anode drive chip 331 and the second anode drive chip 332 are symmetrically assembled on both sides of the light emitting chip 310 along the row direction A-A. In an embodiment, m1=m2=m/2, which facilitates the mass production of the anode drive chip 330 and also facilitates the assembly of the laser emission module 300.
As shown in
The n1 cathode drive bonding points 341a set on the surface 3411 of the first cathode drive chip 341 are bonded and connected to the n1 common cathode end bonding points 411b located on the third side edge 4133c through n1 third bonding wires 153, to achieve a one-to-one electrical connection between the n1 cathode drive circuits 140 and the n1 common cathode ends 311b. The n2 cathode drive bonding points 341a set on the surface 3421 of the second cathode drive chip 342 are respectively bonded and connected to the n2 common cathode end bonding points 411b located on the fourth side edge 4133d through n2 third bonding wires 153, to achieve a one-to-one electrical connection between the n2 cathode drive circuits 140 and the n2 common cathode ends 311b.
Further, the first cathode drive chip 341 and the second cathode drive chip 342 are symmetrically arranged on both sides of the light emitting chip 310 along the column direction B-B. In an embodiment, n1=n2=n/2, which facilitates the mass production of the cathode drive chip 340, and also facilitates the assembly of the laser emission module 300.
In an embodiment, the laser emission module 100 completes the integration of m anode drive circuits by adopting independently set first anode drive chip 331 and second anode drive chip 332. This can avoid integrating all anode drive circuits 131 on the same chip, which on one hand, would increase the processing difficulty and lead to a cost increase. On the other hand, it would also cause the emission substrate 350 to require a larger size in the layout direction of the anode drive chip, such as column direction B-B, thereby leading to an increase in the size of the emission substrate 350. When a larger anode drive chip is placed on the side of the light emitting chip 310, it not only leads to longer lines between each anode drive bonding point 331a and the corresponding common anode end bonding point 4122a, but also easily causes the anode drive bonding point 331a near the edge position to be much farther from the corresponding common anode end bonding point 411a than the anode drive bonding point 331a in the middle position. This in turn leads to a large difference in line lengths between different position anode drive bonding points 331a and their corresponding common anode terminals 311a, with the lines to the edge position anode drive bonding points 331a being longer. On one hand, the longer the line, the greater the corresponding link impedance, and accordingly, the energy loss when the current is transmitted on the line will also increase. This leads to a decrease in the light emitting power of the laser 311 corresponding to the common anode end bonding point 411a connected to the anode drive bonding point 331a at the edge position. On the other hand, the longer the line, the longer the time for the current to be transmitted on the line, which leads to a slower response speed of the laser 311 corresponding to the common anode end bonding point 411a connected to the anode drive bonding point 331a at the edge position.
In an embodiment, the laser emission module 100 completes the integration of n anode drive circuits by adopting independently set first cathode drive chip 341 and second cathode drive chip 342. This can avoid integrating all cathode drive circuits 140 on the same chip, which increases the difficulty of processing and lead to cost increase, and it would also cause the emission substrate 350 to require larger dimensions in the direction of laying out the cathode drive chips, such as the row direction A-A, thereby leading to an increase in the size of the emission substrate 350. When a larger-sized cathode drive chip is placed on the side of the light emitting chip 310, it not only causes the lines between each cathode drive bonding point 341a and the corresponding common cathode end bonding point 411b to be longer, but also causes the distance between the cathode drive bonding point 341a near the edge and the corresponding common cathode end bonding point 411b to be much greater than the distance between the cathode drive bonding point 341a in the middle and the corresponding common cathode end bonding point 411b. This in turn leads to a large difference in line lengths between different positions of the cathode drive bonding point 341a and the corresponding common cathode end bonding point 411b. The line from the cathode drive bonding point 341a at the edge to the corresponding common cathode end bonding point 411b is longer, and correspondingly, the link impedance is larger, which then leads to an increase in energy loss on the line, reducing the luminous power and efficiency of the laser 311.
The difference in line length between the anode drive bonding points 331a located at different positions and the corresponding common anode end bonding points 411a is relatively large, which will cause inconsistency in the luminous power and response speed of the lasers 311 corresponding to the common anode end bonding points 411a connected by the anode drive bonding points 331a at different positions. This affects the luminous uniformity of the laser emission module 300, and in turn affects the ranging performance of the laser ranging device.
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Further, the second pad 132a and the third pad 132b corresponding to each anode energy storage component 132 are arranged in the row direction A-A with the first pad 331b corresponding to the anode drive bonding point 331a and the fourth pad 411c corresponding to the common anode end bonding point 411a.
In an embodiment, the anode energy storage component 132 uses a storage capacitor. In another embodiment, the anode energy storage component 132 uses a ceramic capacitor.
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Further, the second anode energy storage component pad 1322 corresponding to each anode energy storage component 132 is arranged along the row direction A-A with the first pad 331b corresponding to the anode drive bonding point 331a, and the fourth pad 411c corresponding to the common anode end bonding point 411a.
In an embodiment, the anode energy storage component 132 uses a storage capacitor. In another embodiment, the anode energy storage component 132 uses a silicon capacitor.
The laser emission module 300 provided in this embodiment directly bonds and connects the second anode energy storage component pad 1322 on the anode energy storage component 132 with the anode drive chip 330 and the light emitting chip 310, eliminating the need for a first anode energy storage component pad on the emission substrate 350 for electrical connections between the anode energy storage component 132 and the anode drive chip 330, as well as between the anode energy storage component 132 and the light emitting chip 310. This can further reduce the number of solder joints on the emission substrate 350 and reduce the area of the emission substrate 350, thereby further reducing the assembly size of the laser emission module 300.
Further, in an embodiment, respective sums of the lengths of each of the first bonding wire 151 and each of the second bonding wires 152 connected to each of the m anode energy storage components 132 are equal. Specifically, the sum of the lengths of the first bonding wire 151 and the second bonding wire 152 connected to the first anode energy storage component 132 is equal to the sum of the lengths of the first bonding wire 151 and the second bonding wire 152 connected to the second anode energy storage component 132, and so on, up to the mth anode energy storage component 132. This facilitates the control of the consistency of the line lengths between each anode drive circuit 131 and the common anode end 311a, and correspondingly, the link impedance is consistent, which in turn helps to ensure the uniformity of the light emission of the m*n lasers 311.
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Further, the wire lengths of the third bonding wires 153 connected between the n cathode drive bonding points 341a and then common cathode end bonding points 411b are equal. Specifically, the wire length of the third bonding wire 151 set between the sixth solder pad 341b on the first cathode drive bonding point 341a and the seventh solder pad 411d set between the first common cathode end bonding point 411b, and the wire length of the third bonding wire 151 set between the sixth solder pad 341b on the second cathode drive bonding point 341a and the seventh solder pad 411d set between the second common cathode end bonding point 411b, up to the wire length of the third bonding wire 151 set between the sixth solder pad 341b on the mth cathode drive bonding point 341a and the seventh solder pad 411d set between the mth common cathode end bonding point 411b, are all equal. This facilitates the control of the line lengths between each cathode drive circuit 140 and the common cathode end 311b to be consistent, and correspondingly, the link impedance is consistent, which is beneficial to ensure the uniformity of the light emission of the m*n lasers 311.
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The laser emission module 300 encapsulates the devices assembled on the emission substrate 350 through a protective cover 360 and seals the light transmitting opening through a light transmitting cover plate 370. This can reduce the impact of external water vapor, volatile substances, dust, liquid, solder particles, etc. on the light emitting chip 310, anode drive chip 330, anode energy storage component 132, and cathode drive chip 340.
In an embodiment, the laser emission module 100 is packaged using Ball Grid Array (BGA) technology (as shown in
In an embodiment, as shown in
In an embodiment, the emission substrate 350 is a printed circuit board, which provides electrical connections, protection, support, heat dissipation, assembly, and other functions for the chip, in order to achieve the goal of multi-pinning, reducing the volume of the packaged product, reducing the product volume, improving electrical performance and heat dissipation, and achieving ultra-high density or multi-chip modularization.
Further, the emission substrate 350 may be a heat-conductive substrate, which facilitates the dissipation of heat from the devices assembled on the emission substrate 350, thereby avoiding heat accumulation. Here, “heat-conductive substrate” may be a plate material with a good thermal conductivity coefficient. In an embodiment, the heat-conductive substrate uses a ceramic substrate.
In an embodiment, in order to facilitate the chip integration of an anode drive circuit 131 and a cathode drive circuit 140. The elements included in the anode drive circuit 131 are all silicon-based elements. The elements included in the cathode drive circuit 140 are also all silicon-based elements.
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In an embodiment, when a laser 311 at position (x, y) needs to emit light, in the xth anode drive circuit 131 corresponding to the laser 311 at position (x, y), the anode addressing switch element Q1 is turned on, the anode reverse bias switch element Q3 is turned off, and the anode unidirectional conduction element Q2 is in a forward conduction state; the current IL charges the anode energy storage component 132 through the anode addressing switch element Q1 and the anode unidirectional conduction element Q2; the yth cathode drive circuit 140 corresponding to the laser 311 at position (x, y) is turned on, and the anode energy storage component 132, laser 311, and cathode drive circuit 140 form an energy release circuit and use the electrical energy stored in the anode energy storage component 132 to drive the laser 311 at position (x, y) to emit light. When the laser 311 at position (x, y) no longer needs to emit light, in the xth anode drive circuit 131 corresponding to the laser 311 at position (x, y), the anode addressing switch element Q1 is turned off, the anode reverse bias switch element Q3 is turned on, and the anode unidirectional conduction element Q2 is in a reverse bias state; the current IL stops charging the anode energy storage component 132. At this time, the anode unidirectional conduction element Q2 is in a reverse bias state, so that the laser 311 that no longer needs to emit light will not be interfered by the electrical signals of other lasers, thereby improving the isolation between the anode drive circuits 131.
In an embodiment, the anode address switch element Q1 includes a first NMOS tube; the anode unidirectional conduction element Q2 includes a second NMOS tube; the anode reverse bias switch element Q3 includes a third NMOS tube. The source of the second NMOS tube is connected to the source of the first NMOS tube and the drain of the third NMOS tube. The drain of the second NMOS tube is connected to one end of the anode energy storage component 132. The source of the third NMOS tube is grounded to GND. The gate of the first NMOS tube and the gate of the second NMOS tube are connected and receive the anode addressing signal TX_HS_EN_x. The gate of the third NMOS tube receives the inverted anode addressing signal TX_HS_EN_L_x, that is, TX_HS_EN_L_x is out of phase with TX_HS_EN_x.
In an embodiment, when TX_HS_EN_x is at a high level, the first NMOS transistor and the second NMOS transistor are turned on, and the current IL charges the anode energy storage component 132 through the turned-on first NMOS transistor and the second NMOS transistor. When TX_HS_EN_x is at a low level, TX_HS_EN_L_x is at a high level, the third NMOS transistor is turned on and the second NMOS transistor is in a reverse bias state.
In an embodiment, the cathode selection drive circuit 140 includes a cathode selection switch element Q4; the cathode selection switch element Q4 includes a fourth NMOS tube; the drain of the fourth NMOS tube is electrically connected to the corresponding common cathode terminal 311b, the source of the fourth NMOS tube is grounded, and the gate of the fourth NMOS tube receives the cathode selection signal TX_LS_EN_1.
In an embodiment, when the anode selection signal TX_HS_EN_x becomes high level, and the cathode selection signal TX_LS_EN_y becomes high level, the laser 311 at position (x, y) emits light.
The anode selection switch element Q1, the anode unidirectional conduction component Q2, and the anode reverse bias switch element Q3 all adopt silicon-based elements, in order to carry out chip integration processing of the m-channel anode drive circuit 131 on a silicon substrate, to obtain an anode drive chip 330. The cathode selection switch element Q4 adopts a silicon-based element, in order to carry out chip integration processing of the m-channel anode drive circuit 131 on a silicon substrate, to obtain a cathode drive chip 340.
In an embodiment, the current IL is a high-frequency and high-power current. To realize the rapid unidirectional conduction response to the high-frequency, high-power current IL, as shown in
On the second aspect, an embodiment of this application also provides a laser ranging device. The laser ranging device includes a laser emission module 100 according to any of the aforementioned implementation methods, which emits a laser through the laser emission module 100.
In some embodiments, anode drive chip 330 is a chip that is packaged and cathode drive chip 340 is a chip that is packaged. The laser emission module 100 provided by this embodiment, through the packaging treatment of the anode drive chip 330 and the cathode drive chip 340, can provide further protection for the anode drive chip 330 and the cathode drive chip 340.
In an embodiment, the anode drive chip 330 is packaged using Ball Grid Array (BGA) technology, and the bottom of the anode drive chip 330 is equipped with m anode driving solder points; the m anode driving solder points are electrically connected to the m anode drive circuits 131 integrated inside the anode drive chip 330 in a one-to-one correspondence; the m anode driving solder points are soldered on the emission substrate 350, and are electrically connected to the m anode drive solder pads 354 set on the emission substrate 350 in a one-to-one correspondence (as shown in
Further, in some embodiments, as shown in
As shown in
In an embodiment, the cathode drive chip 340 is packaged using Ball Grid Array (BGA) technology, and the bottom of the cathode drive chip 340 is equipped with n cathode drive solder points (not shown); the n cathode drive solder points are electrically connected to the n cathode drive circuits 140 integrated inside the cathode drive chip 340 in a one-to-one correspondence; the n cathode drive solder points are soldered on the emission substrate 350, and are electrically connected to the n cathode drive solder pads 355 set on the emission substrate 350 in a one-to-one correspondence (as shown in
In an embodiment, the anode drive chip 330 and the cathode drive chip 340 are packaged using Ball Grid Array (BGA) technology. At this time, m anode driving solder points are located at the bottom of the anode drive chip 330 and n cathode drive solder joints are located at the bottom of the cathode drive chip 340. In an embodiment, the anode drive chip 330 and the cathode drive chip 340 may be packaged using Land Grid Array (LGA) or Quad Flat No-leads (QFN) packaging technology.
In an embodiment, when the anode drive chip 330 and the cathode drive chip 340 are packaged using Quad Flat No-leads (QFN) packaging technology, m anode drive solder points are located on the bottom surface of the anode drive chip 330. n cathode drive solder points are located on the bottom surface of the cathode drive chip 340. When the anode drive chip 330 and the cathode drive chip 340 are packaged using Land Grid Array (LGA) packaging technology, m anode drive solder points are located on the side surface of the anode drive chip 330, n cathode drive solder points are located on the side surface of the cathode drive chip 340.
As shown in
In an embodiment, both the third anode drive chip 333 and the fourth anode drive chip 334 are bare chips. The third anode drive chip 333 internally integrates m3 anode drive circuits, and m3 anode drive bonding points (not shown) are set on the surface of the third anode drive chip 333, which are electrically connected to the m3 anode drive circuits correspondingly. The m3 anode energy storage components 132 corresponding to the third anode drive chip 333 are assembled on the first board surface 351 and are bonded to the m3 anode drive bonding points on the third anode drive chip 333 through m3 first bonding wires (not shown), thereby achieving corresponding electrical connections with the m3 anode drive circuits. The m3 anode energy storage components 132 corresponding to the third anode drive chip 333 are also bonded to the m3 common anode end bonding points through m3 second bonding wires, to achieve corresponding electrical connections with the m3 common anode ends.
The fourth anode drive chip 334 integrates m4 anode drive circuits internally, and m4 anode drive bonding points (not shown) are set on the surface of the fourth anode drive chip 334, which are electrically connected to the m4 anode drive circuits correspondingly. The m4 anode energy storage components 132 corresponding to the fourth anode drive chip 334 are assembled on the second board surface 352 and are bonded to the m4 anode drive bonding points on the fourth anode drive chip 334 through m4 first bonding wires (not shown), thereby achieving corresponding electrical connections with the m4 anode drive circuits. The m4 anode energy storage components 132 corresponding to the fourth anode drive chip 334 are bonded to the m4 common anode end bonding points through m4 second bonding wires, to achieve corresponding electrical connections with the m4 common anode ends, wherein m3 and m4 are positive integers, and m3+m4=m, m3≥1, m4≥1.
The third cathode drive chip 343 internally integrates n3 cathode drive circuits, and the surface of the third cathode drive chip 343 is equipped with n3 cathode drive bonding points (not shown), which are electrically connected to the n3 cathode drive circuits in a one-to-one correspondence; the n3 cathode drive bonding points are bonded and connected to the n3 common cathode end bonding points through n3 third bonding wires, thereby realizing the one-to-one electrical connection between the n3 cathode drive circuits and the n3 common cathode ends 311b. The fourth cathode drive chip 344 internally integrates n4 cathode drive circuits, and the surface of the fourth cathode drive chip 344 is equipped with n4 cathode drive bonding points (not shown in the figure), which are electrically connected to the n4 cathode drive circuits in a one-to-one correspondence; the n4 cathode drive bonding points are bonded and connected to the n4 common cathode end bonding points through n4 fourth bonding wires, thereby realizing the one-to-one electrical connection between the n4 cathode drive circuits and the n4 common cathode ends, wherein n3 and n4 are both positive integers, and n3+n4=n, n3≥1, n4≥1.
In an embodiment, the second bonding wire includes a single-sided second bonding wire and a double-sided second bonding wire. The number of single-sided second bonding wires is m3. The m3 single-sided second bonding wires are located on the side of the emission substrate 350 close to the first board surface 351, used for realizing the bonding connection of m3 anode energy storage components 132 corresponding to the third anode drive chip 333 set on the first board surface 351 with m3 common anode end bonding points. The number of double-sided second bonding wires is m4. One end of the m4 double-sided second bonding wires is bonded to m4 anode energy storage components 132 corresponding to the fourth anode drive chip 334 set on the second board surface 352, and the other end passes through the emission substrate 350 and is bonded to the m3 common anode end bonding points.
In an embodiment, the double-sided second bonding wire includes a first sub-bonding wire and a second sub-bonding wire; one end of the first sub-bonding wire is bonded to the corresponding anode energy storage component, and the other end is bound to the first solder point (not shown) on the second board surface 352 of the emission substrate 350; one end of the second sub-bonding wire is bonded to the corresponding common anode end bonding point, and the other end is bound to the second solder point (not shown) on the first board surface 351 of the emission substrate 350. The first solder point and the second solder point are electrically connected through the circuit inside the emission substrate 350, so as to realize the electrical connection between the first sub-bonding wire and the second sub-bonding wire, and further to realize the electrical connection between the anode energy storage component 132 corresponding to the fourth anode drive chip 334 and the corresponding common anode end bonding point.
In an embodiment, the third bonding wire includes a single-sided third bonding wire and a double-sided third bonding wire. The number of single-sided third bonding wires is n3. The n3 single-sided third bonding wires are located on the side of the emission substrate 350 close to the first board surface 351, used to achieve the bonding connection between the n3 cathode drive bonding points corresponding to the third cathode drive chip 343 set on the first board surface 351 and the n3 common cathode end bonding points. The number of double-sided third bonding wires is n4. One end of the n4 double-sided third bonding wires is bonded to the n4 cathode drive bonding points corresponding to the fourth cathode drive chip 334 set on the second board surface 352, and the other end passes through the emission substrate 350 and is bonded to the n4 common cathode end bonding points.
In an embodiment, the double-sided third bonding wire includes a third sub-bonding wire and a fourth sub-bonding wire; one end of the third sub-bonding wire is bonded to the corresponding cathode drive bonding point, and the other end is bound to the third solder point (not shown) on the second board surface 352 of the emission substrate 350; one end of the fourth sub-bonding wire is bonded to the corresponding common cathode end bonding point, and the other end is bound to the fourth solder point (not shown) on the first board surface 351 of the emission substrate 350. The third solder point and the fourth solder point are electrically connected through the internal circuit of the emission substrate 350, to achieve the electrical connection of the third sub-bonding wire and the fourth sub-bonding wire, and to further realize the electrical connection of the cathode drive bonding point on the fourth cathode drive chip 344 with the corresponding common cathode end bonding point.
In an embodiment, by setting up the third anode drive chip 333 and the fourth anode drive chip 334 respectively on the first board surface 351 and the second board surface 352 of the emission substrate 350, and by assembling the third cathode drive chip 343 and the fourth cathode drive chip 344 respectively on the first board surface 351 and the second board surface 352, integrating all anode drive circuits 131 into a single anode drive chip and integrating all cathode drive circuits 140 into a single cathode drive chip can be avoided. On one hand, this would increase the difficulty of processing, leading to an increase in cost. On the other hand, it would also cause the emission substrate 350 to require larger dimensions in the direction of laying out the anode drive chip, such as the column direction B-B, thereby leading to an increase in the size of the emission substrate 350.
In an embodiment, the light emitting chip 310 is provided with m common anode end bonding points on one side along the row direction A-A; the light emitting chip 310 is provided with n common cathode bonding points on one side along the column direction B-B. As shown in
In an embodiment, the light emitting chip 310 is respectively provided with m1 common anode end bonding points and m2 common anode end bonding points on both sides along the row direction A-A. As shown in
In an embodiment, as shown in
In an embodiment, as shown in
Further, the first sub-anode drive chip 3331 and the second sub-anode drive chip 3332 are symmetrically assembled on both sides of the light emitting chip 310 along the row direction A-A. The third sub-anode drive chip 3341 and the fourth sub-anode drive chip 3342 are also symmetrically assembled on both sides of the light emitting chip 310 along the row direction A-A.
In an embodiment, m31=m32=m3/2, m41=m42=m4/2, which facilitates the mass production of the anode drive chip 330, and also facilitates the assembly of the laser emission module 300.
In an embodiment, the light emitting chip 310 has n1 common cathode bonding points and n2 common cathode bonding points set on both sides along the column direction A-A. As shown in
In an embodiment, as shown in
Further, the first sub-cathode drive chip 3431 and the second sub-cathode drive chip 3432 are symmetrically assembled on both sides of the light emitting chip 310 along the row direction A-A. A third sub-cathode drive chip 3441 and a fourth sub-cathode drive chip 3442 are symmetrically assembled on both sides of the light emitting chip 310 along the row direction A-A.
In an embodiment, n31=n32=n3/2, n41=n42=n4/2, which facilitates the mass production of the anode drive chip 330, and also facilitates the assembly of the laser emission module 300.
In some embodiments, the third anode drive chip 333 and the fourth anode drive chip 334 are packaged chips.
In an embodiment, the third anode drive chip 333 is packaged using Ball Grid Array (BGA) technology, and the bottom of the third anode drive chip 333 is equipped with m3 anode driving solder points; the m3 anode driving solder points are electrically connected to the m3 anode drive circuits integrated within the third anode drive chip 333 in a one-to-one correspondence; the m3 anode driving solder points are soldered onto the first board surface 351 of the emission substrate 350, and are electrically connected to the m3 anode drive solder pads set on the emission substrate 350 in a one-to-one correspondence; the emission substrate 350 also has m3 first anode energy storage component solder pads (not shown), the m3 first anode energy storage component solder pads are electrically connected to the m3 anode energy storage components 132 in a one-to-one correspondence; a fourth solder pad is set on each common anode end bonding point (not shown); the m3 first anode energy storage component solder pads are soldered and connected to the m3 anode drive solder pads through the m3 first printed circuits set on the first board surface 351 of the emission substrate 350 (not shown), to achieve bonding connection with the m3 anode driving solder points, and to further realize the one-to-one electrical connection between the m3 anode energy storage components 132 and the m3 anode drive circuits 131; the m3 first anode energy storage component solder pads are also soldered and connected to the m3 fourth solder pads 411c through the m3 single-sided second bonding wires, to achieve bonding connection with the m3 common anode end bonding points, and thus realize the one-to-one electrical connection between the m3 first anode energy storage components 132 and the m3 common anode terminals 311a.
In an embodiment, the surface of each anode energy storage component 132 is equipped with a second anode energy storage component pad; m3 second anode energy storage component pads are welded and connected to m anode drive pads 354 through m3 first bonding wires, to achieve a bond connection with m anode drive weld points, thereby realizing a one-to-one electrical connection between m3 anode energy storage components 132 and m3 anode drive circuits 131.
In an embodiment, the fourth anode drive chip 334 is packaged using Ball Grid Array (BGA) technology. The bottom of the fourth anode drive chip 334 is equipped with m4 anode driving solder points and the m4 anode driving solder points are electrically connected to the m4 anode drive circuits integrated within the fourth anode drive chip 334 in a one-to-one correspondence. The m4 anode driving solder points are soldered onto the second board surface 352 of the emission substrate 350 and are electrically connected in a one-to-one correspondence with the m4 anode drive solder pads set on the emission substrate 350 (not shown). The emission substrate 350 also has m4 first anode energy storage component solder pads, which are electrically connected in a one-to-one correspondence with the m4 anode energy storage components 132. A fourth solder pad is set on each common anode end bonding point (not shown). The m4 first anode energy storage component solder pads are connected by soldering to the m3 anode drive solder pads through the m4 first printed circuits set on the second board surface 352 of the emission substrate 350 (not shown), to achieve bonding connection with the m4 anode driving solder points, and thus to realize the one-to-one electrical connection of the m4 anode energy storage components 132 with the m4 anode drive circuits. The m4 first anode energy storage component solder pads are also connected by soldering to the m4 fourth solder pads 411c through the m4 double-sided second bonding wires, to achieve bonding connection with the m4 common anode end bonding points, and thus to realize the one-to-one electrical connection of the m4 first anode energy storage components 132 with the m4 common anode terminals 311a.
In an embodiment, the surfaces of m4 anode energy storage components 132 are equipped with a second anode energy storage component pad (not shown). The m4 second anode energy storage component pads are soldered to m4 anode drive pads 354 via m4 first bonding wires, to achieve a bond connection with m4 anode drive solder points, thereby realizing a one-to-one electrical connection between the m4 anode energy storage components 132 and the m4 anode drive circuits 131.
In an embodiment, the third cathode drive chip 343 is packaged using Ball Grid Array (BGA) technology. The bottom surface of the third cathode drive chip 343 is equipped with n3 cathode drive solder points (not shown); the n3 cathode drive solder points are electrically connected to the n3 cathode drive circuits integrated within the third cathode drive chip 343 in a one-to-one correspondence. The n3 cathode drive solder points are soldered onto the first board surface 351 of the emission substrate 350 (not shown) and are electrically connected in a one-to-one correspondence with the n3 cathode drive solder pads set on the first board surface 351 of the emission substrate 350; and a seventh solder pad is set on each common cathode bonding point. The n3 cathode drive solder pads are connected to the n3 seventh solder pads through n3 single-sided third bonding wires, to achieve bonding connection with the n3 common cathode bonding points, thereby realizing the electrical connection of the n3 cathode drive circuits with the n3 common cathodes in a one-to-one correspondence.
In an embodiment, the fourth cathode drive chip 344 is packaged using Ball Grid Array (BGA) technology. The bottom surface of the fourth cathode drive chip 344 is equipped with n4 cathode drive solder points (not shown); the n4 cathode drive solder points are electrically connected to the n4 cathode drive circuits integrated within the fourth cathode drive chip 344 in a one-to-one correspondence. The n4 cathode drive solder points are soldered onto the second board surface 352 of the emission substrate 350, and are electrically connected in a one-to-one correspondence with the n4 cathode drive solder pads set on the second board surface 352 of the emission substrate 350 (not shown); and a seventh solder pad is set on each common cathode bonding point. The n4 cathode drive solder pads are connected to the n4 seventh solder pads through n4 double-sided third bonding wires, to achieve bonding connection with the n4 common cathode bonding points, thereby realizing the one-to-one electrical connection between the n4 cathode drive circuits and the n4 common cathode ends.
In some embodiments, as shown in
In an embodiment, the drive module 30104 can selectively drive different groups of VCSELs to emit light beams at different times, where each VCSEL in the same group can be in series or parallel and need to emit light beams simultaneously under the drive of the drive module 30104. In an embodiment, the drive module 30104 includes multiple drive switches, and the conduction and disconnection of different drive switches are selected by setting pulse signals to control different groups of Vertical Cavity Surface Emitting Lasers to emit light beams at different times. In an embodiment, the drive module 30104 can also select different groups of VCSELs to emit light at the same time through the setting of pulse signals, to increase the emission power.
In an embodiment, drive module includes at least a first high-side drive chip and at least a first low-side drive chip. The first high-side drive chip and the first low-side drive chip drive at least one group of Vertical Cavity Surface Emitting Lasers (VCSELs) to emit light by turning on at least one group of the at least two groups of VCSELs. Single-side driving is generally used to drive a group of VCSELs to emit light. In embodiments of this application, dual-side driving is used, that is, a group of VCSELs can only emit light beams when driven by a high-side drive chip and a low-side drive chip. This can improve the flexibility of control and facilitate the selection of VCSELs to be driven to emit light beams from at least two groups of VCSELs when integrated driving is used. The drive module can also only comprise a high-side drive chip or only comprise a low-side drive chip.
There are various ways to connect the VCSEL, driver module, and capacitor in the emission packaging module. An example of one such method is described below in conjunction with
There are various ways to implement the energy conversion circuit and energy release circuit in the transmitter module. In an embodiment, as shown in
In an embodiment, one end of the power supply VCC and the inductor L1 are connected, while the other end of the inductor L1 is separately connected to the source of the drive switch Q1 and the source of the drive switch Q2. The gate of the drive switch Q1 is used to receive the first pulse control signal, and its drain is grounded. The gate of the drive switch Q2 is used to receive the second pulse control signal, and its drain is connected to the anode of the diode switch D1. The cathode of the diode switch D1 is separately connected to the positive plate of the energy storage capacitor C2 and the anode of the VCSEL 31. The cathode of the VCSEL 31 is connected to one pole of the drive switch Q3, the negative plate of the energy storage capacitor C2 is grounded, and among the other two poles of the drive switch Q3, the drain is grounded, and the gate is used to receive the third pulse control signal.
The circuit topology shown in
In some examples, the drive module in the emission packaging module 31022 includes x anode drive modules and y cathode drive modules. The emission packaging module 31022 includes p energy storage capacitors and n groups of VCSELs. The x anode drive modules correspond to the p energy storage capacitors, where p is a positive integer greater than or equal to 1 and less than or equal to n. x is a positive integer less than or equal to p. Each anode drive module corresponds to at least one energy storage capacitor, and each anode drive module corresponds to different energy storage capacitors. The y cathode drive modules correspond to the n groups of VCSELs, where each cathode drive module corresponds to at least one group of VCSELs, and each cathode drive module corresponds to different groups of VCSELs. Here, n is a positive integer greater than 1, and y is a positive integer less than or equal to n. Each anode drive module can include a drive switch Q2 and/or a diode switch D1 as shown in
In an embodiment, the n groups of VCSEL can be used to emit light beams at the same time, or the emission times are staggered, divided into n times to emit light beams in sequence. Before each group of VCSEL in then groups of VCSEL emits a light beam, the anode drive module corresponding to a group of VCSEL of the light beam is used to transfer the energy in the charging circuit to the corresponding energy storage capacitor, and the corresponding cathode drive module is used to release the energy in the corresponding energy storage capacitor to the group of VCSEL, so as to make the group of VCSEL emit a light beam. In an embodiment, the emission module can also include m power supplies and q charging circuits (where m q, and m is an integer greater than or equal to 1), corresponding to the p energy storage capacitors in the emission packaging module, the p energy storage capacitors and the n groups of VCSEL correspond. When m is less than q, in at least part of the power supplies, each power supply corresponds to no less than 2 charging circuits. When q is less than p, in at least part of the charging circuits, each charging circuit corresponds to no less than 2 energy storage capacitors. When p is less than n, in at least part of the energy storage capacitors, each energy storage capacitor corresponds to no less than 2 groups of VCSEL. At least before a group of VCSEL emits a light beam, the power supply corresponding to the group of VCSEL is used to charge energy into the corresponding charging circuit, and the corresponding energy conversion circuit is used to transfer the energy in the corresponding charging circuit to the energy storage capacitor corresponding to the group of VCSEL before the group of VCSEL emits a light beam.
In an embodiment, the voltage values of the m power sources can be equal or unequal. In an embodiment, m groups of power sources can drive different numbers of energy conversion circuits. The power source corresponding to the middle area of the detection field can drive fewer groups of energy release circuits, and the power source corresponding to the edge area of the detection field can drive more groups of potential energy circuits. For example, if the power source in the middle area drives a group of energy release circuits, and the power source in the edge area drives b groups of energy release circuits, then By controlling the voltage values of the m power sources and the number of energy release circuits in the emission array in the detection field corresponding to the m power sources, the detection requirements can be further matched based on the emission module, achieving flexibility in detection.
As shown in
In some embodiments, the at least two groups of VCSELs are VCSEL arrays arranged in a rectangular array, and each group of VCSELs is an element in the VCSEL array; a first high-side drive chip is used to drive at least one row of elements selected in the VCSEL array; a first low-side drive chip is used to drive at least one column of elements selected in the VCSEL array. The group of VCSELs that are simultaneously located in the row selected by the first high-side drive chip and the column selected by the first low-side drive chip will be successfully driven to emit a light beam. In this way, by selecting the VCSELs to be driven through the selection of rows and columns, the flexibility of control can be improved. The at least two groups of VCSELs in the embodiments of this application can also be arranged in arrays of other shapes, such as circular arrays, elliptical arrays, etc. The drive module can also discretely drive different groups of VCSELs. In an embodiment, one group of VCSELs includes at least one VCSEL emitter. In an embodiment, a group of VCSELs can also include multiple VCSEL emitters, such as 2, 3, 8, 9, and the number of VCSEL emitters included in a group of VCSELs in this application is not limited.
In an embodiment, by systematizing at least two sets of VCSELs and their drive modules and energy storage capacitors in the emission module into an emission packaging module through local packaging, the packaged emission packaging module can be mounted on the circuit board during assembly. Compared with directly mounting multiple VCSELs and their driving modules and energy storage capacitors on the circuit board, once a scrapped VCSEL appears, it will cause the entire product's circuit board to be scrapped. This embodiment of the application can better pre-screen the emission packaging modules, achieving higher yield control. This embodiment of the application can also reduce the difficulty of the process. In existing products, it is often required that each VCSEL be precisely aligned and mounted on the circuit board. In this application, by pre-packaging to form an emission packaging module, the difficulty of packaging each VCSEL onto the circuit board can be reduced. In addition, each VCSEL and its energy storage capacitor and driving module are packaged in the emission packaging module, which can reduce the parasitic parameters in the control drive circuit. Moreover, by integrating the key device modules in the emission module and overall packaging, this form can ensure the consistency and stability of multi-channel transmission devices, and the airtight packaging structure ensures the stability of the internal environment, thereby improving the reliability of the core power devices and driving devices, and enhancing the overall reliability of the emission module. Currently, the reliability requirements for automotive devices are very high. Devices are usually subjected to WHTOL tests. The test environment is usually a high temperature and high humidity environment. For unpackaged bare die devices, water molecules or impurities often infiltrate into the edges of the device or relatively weak positions of the protective layer, which can easily cause internal conduction or open circuit failure of the device due to long-term electromigration effects. In some embodiments, after the VCSEL and its driving module and energy storage capacitor are systematized into an emission packaging module through local packaging and then fixed to the circuit board of the emission module, the emission module in this application is more likely to meet the reliability requirements of automotive devices.
As shown in
In an embodiment, the emission packaging module also includes at least one bootstrap capacitor, used for activating or maintaining the drive state of the first high-side drive chip. For example, as shown in
In an embodiment, the emission packaging module also includes at least one decoupling capacitor corresponding to the at least one high-side drive chip and/or the at least one low-side drive chip. In the emission packaging module, the at least one high-side drive chip and/or at least one low-side drive chip are each connected to the negative pole of the power supply (or ground) through the at least one decoupling capacitor. For example, all high-side drive chips are connected to the negative pole of the power supply (or ground) through a decoupling capacitor, and all low-side drive chips are connected to the negative pole of the power supply (or ground) through another decoupling capacitor; or, all high-side and low-side drive chips are connected to the negative pole of the power supply (or ground) through the same decoupling capacitor; or, each high-side drive chip is connected to the negative pole of the power supply (or ground) through different decoupling capacitors, and, each low-side drive chip is connected to the negative pole of the power supply (or ground) through different decoupling capacitors. As shown in
The operating voltages of a general high-side driver chip and a low-side driver chip are each fixed at a certain voltage value. The power supply is first decoupled by a capacitor before it is supplied to the high-side driver chip and the low-side driver chip. This can prevent parasitic oscillations caused by the positive feedback path formed by the circuit through the power supply VCC, that is, it can prevent the changes in the size of the circuit current from affecting the normal operation of the circuit due to the current fluctuations formed in the power supply circuit. Therefore, it can effectively eliminate the parasitic coupling between circuits to ensure the relative stability of the power supply. Optionally, the pin of at least the first high-side driver chip and/or at least the first low-side driver chip is set adjacent to the corresponding decoupling capacitor.
As shown in
In an embodiment, the drive module may also include a second low-side drive chip 34514, and the first low-side drive chip 34512 is located on the opposite sides of the VCSEL array, respectively used to drive the lasers in different areas of the VCSEL array. For example, as shown in
Compared to an embodiment with a high-side driver chip and a low-side driver chip, examples with two high-side driver chips and/or two low-side driver chips can drive more groups of VCSELs simultaneously, making it convenient to choose the number of VCSELs emitting light beams at the same time according to detection needs, thereby further enhancing the flexibility of detection. The emission packaging module may contain two high-side driver chips and one low-side driver chip. In an embodiment, the two high-side driver chips can drive different groups of VCSELs in different rows, and the one low-side driver chip can drive all groups of VCSELs in all columns. Alternatively, the emission packaging module may contain one high-side driver chip and two low-side driver chips. In an embodiment, the one high-side driver chip can drive all groups of VCSELs in all rows, and the two low-side driver chips can drive different groups of VCSELs in different columns.
In an embodiment, as shown in
As shown in
A low-side driver chip 3565 is respectively set on both the upper and lower sides of the VCSEL array 60. The pins of the low-side driver chip 3565 are arranged on the side of the low-side driver chip 3565 facing away from the VCSEL array 60. The decoupling capacitors 3565 corresponding to the low-side driver chip 3565 are respectively arranged on the side of the low-side driver chip 3565 facing away from the VCSEL array 60 and are set adjacent to the pins of the low-side driver chip 3565.
In
There are various ways to implement the emission packaging module. As shown in
In an embodiment, the at least one capacitor 30105 in the emission packaging module can be mounted to the substrate 30101 using Surface Mounted Technology (SMT). In an embodiment, this at least one capacitor 30105 can be connected to the corresponding VCSEL 103 via a lead 30108.
In an embodiment, the light transmissible cover plate 30102 in the emission packaging module includes a cover plate area 301021, and a light window area 301022 located on the light path of the at least two groups of VCSELs. In an embodiment, the cover plate area 301021 is made of stainless steel or fusible alloy. In an embodiment, the thermal expansion coefficient of the cover plate area 301021 is within [12×10−6/deg, 15×10−6/deg], and the thermal expansion coefficient of the substrate 30101 is within [10×10−6/deg, 12×10−6/deg]. In this way, there is a relatively small thermal mismatch between the materials of the cover plate and the substrate, avoiding the failure of the encapsulation of the emission packaging module.
In an embodiment, the cover plate area 301021 is mounted to the substrate 30101 through a first mounting adhesive, and is mounted to the light window area 301022 through a second mounting adhesive. The first mounting adhesive and the second mounting adhesive can be the same or different. In an embodiment, the first mounting adhesive is a single-component thermosetting epoxy resin, and the second mounting adhesive is a single-component thermosetting silicone rubber.
In an embodiment, the substrate 30101 is a BT resin-based copper clad laminate. In an embodiment, the area where the substrate 30101 contacts with at least two groups of VCSEL 103 is filled with metal. For example, the substrate is designed with copper filled holes corresponding to the VCSEL array area, which can enable the VCSEL area to achieve a higher thermal conductivity.
In an embodiment, the emission packaging module is packaged in the form of a Ball Grid Array (BGA) to facilitate mounting onto a circuit board in the emission module.
In an embodiment, as shown in
In an embodiment, as shown in
There are various methods for the packaging process of an emission packaging module. In an embodiment, the packaging process of the emission packaging module includes a capacitor mounting process, a VCSEL and driver module mounting process, an optical cover mounting process, a BGA ball planting process, and a substrate dicing process.
In an embodiment, the VCSEL mounting process occurs after the capacitor mounting process. In an embodiment, the capacitor mounting process includes baking the encapsulation substrate, mounting the capacitor in the emission packaging module onto the baked substrate via SMT, and cleaning the mounted capacitor and substrate. In an embodiment, the VCSEL and driver module mounting process includes: applying silver paste and chip bonding to the VCSEL, then baking the silver paste to cure it; applying adhesive and chip bonding to the driver chip in the driver module, then baking the silver paste to cure it; packaging the baked and cured VCSEL and driver module separately into a Land Grid Array (LGA), then performing plasma cleaning; after cleaning, performing wire bonding on the packaged VCSEL and driver module, and inspecting after wire bonding.
In an embodiment, the light cover mounting process includes applying adhesive to a light transmissible cover plate and mounting it to the cover plate, followed by curing. Before the BGA ball planting process, in examples where components need to be mounted on the back of the substrate, these components can also be mounted on the back of the substrate using SMT technology. After the BGA ball planting process on the substrate, the substrate is cut.
Embodiment of this application also provides a LiDAR system, which includes an emission packaging module for emitting laser beams. The emission packaging module can be any of the emission packaging modules described above. As shown in
The technical features of the above embodiments can be combined in any way. To keep the description concise, not all possible combinations of these technical features in the above embodiments have been described. However, as long as there is no contradiction in the combination of these technical features, they should be considered within the scope of this specification. The above embodiments only express a few implementation methods of this application, which are relatively specific and detailed, but should not be understood as limiting the scope of the patent application.
Number | Date | Country | Kind |
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202211360853.7 | Oct 2022 | CN | national |
202310269943.3 | Mar 2023 | CN | national |