Circuit board assembly, transmitting terminal device and laser radar

Abstract

The utility model relates to a circuit board assembly, a transmitting terminal device and a laser radar, the circuit board assembly comprises a circuit board, the circuit board comprises a board body and a cathode guide block, the board body is provided with a mounting hole, and the cathode guide block is filled in the mounting hole and is electrically connected with the board body; a chip; the bonding layer is arranged between the cathode guide block and the chip, so that the chip is fixedly arranged on the cathode guide block, and the chip is electrically connected with the cathode guide block; and a plurality of anode connecting pieces, wherein the anode connecting pieces are respectively and electrically connected with the chip and the circuit board. The cathode of the circuit board assembly does not use gold threads, so that the number of the gold threads can be reduced, and the generation of parasitic inductance can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of laser radar, in particular to a circuit board component, a transmitting end device and a laser radar. Background Art

[0002] With the development of LiDAR technology, the transmitter modules of LiDAR products are gradually moving towards high-power, high-current, narrow-pulse lasers (Vcsel). Therefore, when designing circuit board solutions for LiDAR products, it is necessary to focus on solving problems such as heat dissipation and electrical properties such as narrow laser pulses and waveforms.

[0003] Currently, the popular bonding solution for laser radars on the market is hollow embedded ceramic substrates, such as Figure 1 As shown, in this scheme, the circuit board A1 is bonded to the aluminum-based substrate A2 through a conductive adhesive layer A7, and the ceramic substrate A3 is bonded to the aluminum-based substrate A2 through a thermal conductive adhesive layer A8. The narrow pulse laser A4 is bonded to the ceramic substrate A3 through a conductive adhesive layer A7, and the anode and cathode of the narrow pulse laser are connected to the circuit board A1 respectively by using an anode gold wire A5 and a cathode gold wire A6.

[0004] This solution will cause the bonding gold wire to be too long and the internal resistance and parasitic inductance caused by the gold wire to be too large. Due to the large parasitic inductance of the gold wire, the driving voltage needs to be increased exponentially, causing the driving voltage of some lasers to be increased from 50V to 100V, which makes the design of the circuit board solution more difficult, and the design routing and spacing are also increased, resulting in an increase in production costs and product size, affecting the laser pulse waveform and producing a certain voltage drop, causing uneven light emission at the laser radar transmitter, reduced power, and reduced ranging accuracy, resulting in a decrease in the performance of the laser radar. Utility Model Content

[0005] Based on this, it is necessary to provide a circuit board assembly, a transmitting end device and a laser radar to address the problem of excessive parasitic inductance of the gold wire of existing laser radar products.

[0006] A circuit board assembly, comprising:

[0007] A circuit board, the circuit board comprising a board body and a cathode guide block, the board body having a mounting hole, the cathode guide block filling the mounting hole and being electrically connected to the board body;

[0008] A chip, wherein the chip is fixedly mounted on the cathode guide block and the chip is electrically connected to the cathode guide block; and

[0009] At least one anode connector, wherein the anode connector is electrically connected to the chip and the circuit board respectively.

[0010] In one embodiment, the circuit board assembly satisfies the relationship: 10≤L1 / D≤70;

[0011] Wherein, L1 is the length of the anode connector, and 0.255≤L1≤5mm; D is the width of the anode connector, and 0.01mm≤D≤0.1mm.

[0012] In one of the embodiments, the circuit board assembly further includes an adhesive layer, and the adhesive layer is arranged between the cathode guide block and the chip to fix the chip to the cathode guide block and electrically connect the chip to the cathode guide block.

[0013] In one embodiment, the circuit board assembly satisfies the relationship: 15≤S / d≤1800;

[0014] Wherein, S is the contact area between the adhesive layer and the chip, and 0.1cm 2 ≤S≤5.5cm 2 ; d is the thickness of the adhesive layer.

[0015] In one embodiment, the circuit board assembly satisfies the relationship: 1.5×10 3 ≤S / (R×d)≤5.5×10 7 ;

[0016] Wherein, S is the contact area between the adhesive layer and the chip, and 0.1cm 2 ≤S≤5.5cm 2 ; R is the resistance of the adhesive layer, and 10 -6 ≤R≤10 -4 Ω·cm; d is the thickness of the adhesive layer, and 10μm≤d≤80um.

[0017] In one embodiment, the anode connector is a gold wire, and two ends of the gold wire are electrically connected to the chip and the board respectively.

[0018] In one of the embodiments, the thickness of the cathode guide block is equal to the thickness of the plate body, so that the upper surface of the cathode guide block is flush with the upper surface of the plate body.

[0019] In one of the embodiments, the thickness of the cathode guide block is smaller than the thickness of the plate body.

[0020] In one embodiment, the circuit board assembly satisfies the relationship: 0.8≤d1 / d2≤1.2, wherein d1 is the difference between the thickness of the cathode guide block and the thickness of the board body, and d2 is the sum of the thickness of the chip and the adhesive layer.

[0021] In one embodiment, the difference d1 between the thickness of the cathode guide block and the thickness of the plate body ranges from 200 μm to 300 μm, or the sum d2 of the thickness of the chip and the adhesive layer ranges from 200 μm to 300 μm.

[0022] In one embodiment, the thickness of the cathode guide block is smaller than the thickness of the board body, the upper surface of the chip is flush with the upper surface of the board body, and the anode connector is a metal conductor, and both ends of the metal conductor are respectively welded to the circuit board and the chip.

[0023] In one embodiment, the width D1 of the metal conductor is equal to the diameter of the pad of the chip.

[0024] In one embodiment, the thickness d of the adhesive layer satisfies the relationship 10 μm≤d≤80 μm.

[0025] In one of the embodiments, at least one wire is embedded in the board body, and the board body is provided with a plurality of via holes around the mounting hole, and the via holes are used to allow the wire to pass through so as to electrically connect the cathode guide block with other circuit elements fixed to the board body.

[0026] In one embodiment, the cathode guide block is made of one or a combination of copper, aluminum and silver.

[0027] In one embodiment, the chip is a VSCEL chip or a CMOS chip.

[0028] In one embodiment, the number of the anode connectors is between 10 and 300.

[0029] A transmitting end device, comprising:

[0030] A circuit board assembly as described in any one of the above; and

[0031] The circuit element is fixed on the circuit board assembly and electrically connected to the circuit board assembly.

[0032] A laser radar, comprising:

[0033] A transmitting end device as described in any one of the above; and

[0034] The radar body, the transmitting end device is installed on the radar body.

[0035] The above-mentioned circuit board assembly uses the cathode guide block as the substrate of the chip, and can remove the aluminum-based substrate required by the traditional chip, thereby greatly reducing the overall size of the circuit board assembly and realizing the miniaturization of the laser radar. The chip is bonded to the cathode guide block through the bonding layer, so that the cathode of the chip does not use gold wire, thereby reducing the number of gold wires in the circuit board assembly, reducing the generation of parasitic inductance, and enabling the circuit board assembly to have good heat dissipation performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of the structure and dimensions of a circuit board assembly for a bonding solution of a hollow embedded ceramic substrate of a laser radar in the prior art;

[0037] Figure 2 A schematic diagram of the structure of a circuit board assembly provided for the first example of the present application;

[0038] Figure 3 A schematic top view of a circuit board assembly according to the first example of the present application is shown;

[0039] Figure 4 A schematic diagram of the structure of a circuit board assembly provided for a second example of the present application;

[0040] Figure 5 A schematic diagram showing the welding of gold wires of a circuit board assembly according to the second example of the present application is shown;

[0041] Figure 6 A schematic diagram of the structure of a circuit board assembly provided for a third example of the present application;

[0042] Figure 7 A schematic top view of a circuit board assembly according to the third example of the present application is shown;

[0043] Figure 8 A schematic diagram of welding metal conductors of a circuit board assembly according to the third example of the present application is shown.

[0044] Figure numerals: 10, circuit board; 11, board body; 111, mounting hole; 112, wire; 113, via; 114, solder strip; 12, cathode guide block; 13, circuit element; 20, chip; 21, solder pad; 30, adhesive layer; 41, gold wire; 42, metal conductor; 43, gold wire ball. DETAILED DESCRIPTION

[0045] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0046] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0047] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0048] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0050] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0051] Based on the problem of excessive parasitic inductance of gold wires in existing laser radar products, the present application provides a circuit board assembly. The cathode of the circuit board assembly does not use gold wires, which can reduce the number of gold wires and thus reduce the generation of parasitic inductance.

[0052] For details, please refer to Figures 2 to 8 The circuit board assembly may include a circuit board 10, a chip 20 and a plurality of anode connectors. The circuit board 10 includes a board body 11, a cathode guide block 12 and a circuit element 13. The board body 11 has a mounting hole 111. The cathode guide block 12 is filled in the mounting hole 111 and is electrically connected to the board body 11. The chip 20 is fixed to the cathode guide block 12 and is electrically connected to the cathode guide block 12. The anode connectors are electrically connected to the chip 20 and the circuit board 10, respectively.

[0053] It is understandable that the circuit board assembly uses the cathode guide block 12 as the substrate of the chip 20, and the aluminum-based substrate required by the traditional chip 20 can be removed, thereby greatly reducing the overall size of the circuit board assembly and realizing the miniaturization of the laser radar. The chip 20 is bonded to the cathode guide block 12 through the bonding layer 30, so that the cathode of the chip 20 does not use the gold wire 41, thereby reducing the number of gold wires 41 of the circuit board assembly, reducing the generation of parasitic inductance, and enabling the circuit board assembly to have good heat dissipation performance.

[0054] More specifically, in some of the embodiments, the circuit board assembly satisfies the relationship: 10≤L1 / D≤70; wherein L1 is the length of the anode connector, and 0.255≤L1≤5mm; D is the width of the anode connector, and 0.01mm≤D≤0.1mm.

[0055] The parasitic inductance of a single anode connector can be calculated by the relationship L=K×L1 / D, where K is a proportionality factor of the parasitic inductance, K=0.001 to 0.008.

[0056] According to the above relationship, it can be concluded that the parasitic inductance is related to the length and width of the anode connector. By controlling the length and width of the anode connector, the generation of parasitic inductance can be effectively reduced. The shorter the length of the anode connector and the longer the width, the smaller the parasitic inductance. The longer the length of the anode connector and the shorter the width, the larger the parasitic inductance. Preferably, the circuit board assembly further satisfies the relationship: 10≤L1 / D≤50, and the length of the anode connector further satisfies: 0.255≤L1≤1.25mm, which has a better effect in the preferred case.

[0057] Furthermore, in one of the embodiments, the circuit board assembly also includes an adhesive layer 30 , which has good electrical conductivity and thermal conductivity, and can fix the chip 20 on the cathode guide block 12 and electrically connect the chip 20 to the cathode guide block 12 .

[0058] Preferably, in one embodiment, the circuit board assembly satisfies the relationship: 15≤S / d≤1800; wherein S is the contact area between the adhesive layer 30 and the chip 20, and 0.1 cm 2 ≤S≤5.5cm 2 As a preference, S further satisfies the relationship: 0.1 cm 2 ≤S≤0.25cm 2 It has a better technical effect; d is the thickness of the adhesive layer 30. The circuit board assembly satisfies the above relationship so that the adhesive layer 30 can have both good electrical conductivity and thermal conductivity, and while ensuring the formation of an electrical circuit, it can also transfer the heat of the chip 20, thereby achieving a heat dissipation effect.

[0059] As a preference, the application field of the circuit board assembly of the present application is not limited. Specifically, the range of the best effect varies according to the application field of the circuit board assembly. As an example, when the circuit board assembly is applied in the field of laser radar, the circuit board assembly is 15≤S / d≤300, 0.1cm 2 ≤S≤0.9cm 2 The best effect is achieved within the range of 40≤S / d≤180, 0.3cm2 ≤S≤0.5cm 2 The best effect is achieved within the range of 420≤S / d≤1800, 3cm 2 ≤S≤5.5cm 2 The best effect is achieved within the range of 320≤S / d≤1300, 2cm 2 ≤S≤4cm 2 The best effect is achieved within the range.

[0060] Preferably, in one embodiment, the circuit board assembly satisfies the relationship: 1.5×10 3 ≤S / (R×d)≤5.5×10 7 Wherein, S is the area of ​​the adhesive layer 30, and 0.1cm 2 ≤S≤5.5cm 2 ; R is the resistance of the adhesive layer 30, and 10 -6 ≤R≤10 -4 Ω·cm; d is the thickness of the adhesive layer 30, and 10μm≤d≤80um. By controlling the area and thickness of the adhesive layer 30, the adhesive layer 30 can have good electrical conductivity and thermal conductivity, and while ensuring the formation of an electrical circuit, the heat of the chip 20 can be transferred out, thereby achieving a heat dissipation effect. As a preferred embodiment, the circuit board assembly further satisfies the relationship: 2×10 3 ≤S / (R×d)≤8×10 6 , with more technical effects.

[0061] More preferably, the application field of the circuit board assembly of the present application is not limited. Specifically, the range of the best effect varies according to the application field of the circuit board assembly. As an example, when the circuit board assembly is applied in the field of laser radar, the circuit board assembly is within 1.5×10 3 ≤S / (R×d)≤9×10 8 The best effect is achieved within the range of 4.3×10 3 ≤S / (R×d)≤5.18×10 8 The best effect is achieved within the range of 4.4×10 6 ≤S / (R×d)≤5.3×10 9 The best effect is achieved within the range of 3.2×10 6 ≤S / (R×d)≤4×10 9 The best effect is achieved within the range.

[0062] It is worth noting that the circuit board assembly also satisfies the relationship M=k×S / (R×d), where k is the electrothermal performance proportionality coefficient, k=10^(-9); M is the electrothermal performance of the adhesive layer 30, and 0.3≤M≤2.

[0063] Optionally, in some embodiments, the circuit board assembly can embed the cathode guide block 12 into the mounting hole 111 of the circuit board 10 by one-time processing. The cathode guide block 12 can fill the mounting hole 111 of the circuit board 10 or half fill the mounting hole 111 of the circuit board 10, and the anode connector can be a gold wire 41 or a metal conductor 42 or other conductor connector. When the anode uses the gold wire 41, the gold wire 41 can be welded to the soldering strip 114 of the circuit board 10 and the soldering pad 21 of the chip 20 by using a bonding gold wire process. When the anode uses the metal conductor 42, the metal conductor 42 can be welded to the soldering strip 114 of the circuit board 10 and the soldering pad 21 of the chip 20 by using a carrier tape automatic welding process.

[0064] It is worth noting that the width D of the anode connector may be the diameter of the gold wire 41 or the width of the metal conductor 42 on the pad 21 of the chip 20 .

[0065] Alternatively, if Figure 2 and Figure 3 As shown, in one embodiment, the anode connector is a gold wire 41, and the two ends of the gold wire 41 are electrically connected to the chip 20 and the board body 11 respectively. The cathode guide block 12 fills the circuit board 10. The thickness of the cathode guide block 12 is equal to the thickness of the board body 11, so that the upper surface of the cathode guide block 12 is flush with the upper surface of the board body 11. That is, the cathode guide block 12 fills the mounting hole 111 of the circuit board 10. With such a configuration, the production process of the circuit board assembly is simpler and the production efficiency is higher.

[0066] Alternatively, if Figure 4 As shown, in one embodiment, the anode connector is a gold wire 41, and the two ends of the gold wire 41 are electrically connected to the chip 20 and the board 11 respectively. The thickness of the cathode guide block 12 is less than the thickness of the board 11. That is, the cathode guide block 12 half fills the mounting hole 111 of the circuit board 10. In this way, the value of d1 is controlled during the process of filling the cathode guide block 12, and the value of d2 is controlled during the process of plating the glue layer, and the values ​​of d1 and d2 are kept close, so that the length of the gold wire 41 can be minimized, thereby reducing the generation of parasitic inductance.

[0067] Preferably, in one of the embodiments, the circuit board assembly satisfies the relationship: 0.8≤d1 / d2≤1.2, wherein d1 is the difference between the thickness of the cathode guide block 12 and the thickness of the board body 11 , and d2 is the sum of the thickness of the chip 20 and the adhesive layer 30 .

[0068] More preferably, in one embodiment, the difference d1 between the thickness of the cathode guide block 12 and the thickness of the plate body 11 is in the range of 200 μm to 300 μm, or the sum d2 of the thickness of the chip 20 and the bonding layer 30 is in the range of 200 μm to 300 μm. This arrangement can minimize the length of the gold wire 41 and further reduce the generation of parasitic inductance.

[0069] Furthermore, in one embodiment, the thickness d of the adhesive layer 30 is less than or equal to 80 μm. In this way, by controlling the thickness of the adhesive layer 30 , the length of the gold wire 41 can be controlled to minimize the length of the gold wire 41 and minimize the parasitic inductance.

[0070] Alternatively, if Figure 6 and Figure 7 As shown, in one embodiment, the thickness of the cathode guide block 12 is less than the thickness of the board body 11, the upper surface of the chip 20 is flush with the upper surface of the board body 11, and the anode connector is a metal conductor 42, and the two ends of the metal conductor 42 are respectively welded to the circuit board 10 and the chip 20. That is, the cathode guide block 12 half fills the mounting hole 111 of the circuit board 10. Since the metal conductor 42 can be directly soldered to the soldering tape 114 of the circuit board 10 and the soldering pad 21 of the chip 20 through the carrier automatic soldering process, no solder balls will be generated, and thus the width of the metal conductor 42 is not limited by the size of the solder balls. The width of the metal conductor 42 is usually larger than the diameter of the gold wire 41. In this way, the thickness of the anode connector can be increased. According to the parasitic inductance formula L=K×L1 / D, L is the parasitic inductance, K is the proportionality coefficient, D is the width or diameter of the anode connector, and L1 is the length of the anode connector; therefore, the larger the width of the metal conductor 42, the smaller the parasitic inductance, and the metal conductor 42 structure can further reduce the parasitic inductance.

[0071] Preferably, if Figure 8 As shown, in one embodiment, the width D1 of the metal conductor 42 is equal to the diameter of the pad 21 of the chip 20. In this way, the width of the metal conductor 42 is maximized, which can minimize the parasitic inductance.

[0072] Exemplarily, the metal conductor 42 may be a copper conductor.

[0073] It is worth noting that when using the automatic soldering process with the carrier tape, a standardized tape reel (most commonly 100 m) can be used to achieve bonding of multiple solder joints of the chip 20 and the lead frame of the circuit board 10, with fast bonding speed, high production efficiency, and easier industrial-scale production.

[0074] Furthermore, if Figure 2As shown, in one embodiment, a plurality of wires 112 are embedded in the board body 11, and a plurality of via holes 113 are provided around the mounting hole 111 on the board body 11, and the via holes 113 are used to allow the wires 112 to pass through so as to electrically connect the cathode guide block 12 with other circuit elements fixed to the board body 11. In this way, by providing a plurality of via holes 113 on the circuit board 10, the cathode guide block 12 and the circuit element 13 are connected by the via holes 113 and the wires 112 to achieve electrical connection, which is conducive to reducing the volume of the circuit board assembly and can improve electrical conductivity and stability.

[0075] Optionally, in one embodiment, the cathode guide block 12 is made of a conductor material with a thermal conductivity greater than 190 mW / (m·K). In this way, the good thermal conductivity of the cathode guide block 12 can be used to enhance the heat dissipation capacity of the circuit board assembly and solve the heat dissipation problem of the laser radar.

[0076] Optionally, in one of the embodiments, the material of the cathode guide block 12 is one material or a combination of multiple materials selected from copper, aluminum and silver. Copper, aluminum and silver materials have good thermal conductivity, which helps to enhance the heat dissipation capacity of the circuit board assembly. Among them, the thermal conductivity of copper material is 398W / (m·K), and the thermal conductivity of aluminum is 238W / (m·K). Compared with the mainstream aluminum materials on the market, such as aluminum oxide Al2O3 (thermal conductivity is 25W / (m·K)) and aluminum nitride AlN (thermal conductivity is 170W / (m·K)), it has better thermal conductivity.

[0077] Optionally, in one embodiment, the chip 20 includes but is not limited to a VSCEL chip or a CMOS chip. It can also be a SPAD chip, a matrix pixel lamp chip, an LED chip, an LD chip, a DMD chip, an LCOS chip, and a MEMS chip. The chip has different functions in different applications. For example, in the application of laser radar or vehicle camera, it can not only emit light beams but also receive light beams. In the application of vehicle lights or head-up display, it can not only emit light beams but also reflect light beams. Specifically, different functions can be realized according to different applications.

[0078] Optionally, in some embodiments, the number of the anode connectors is between 10 and 300. According to the number n of the anode connectors, combined with the relationship L=n×K×L1 / D, the total parasitic inductance of the circuit board assembly of the present application can be calculated.

[0079] Furthermore, the present application also provides a transmitter device, which includes a circuit board assembly and a circuit element as described above, and the circuit element 13 is fixed to the circuit board assembly and electrically connected to the circuit board assembly. The circuit element 13 may include a driving chip, a capacitor and other circuit elements 13 necessary for a laser radar, and the circuit element 13 may be electrically connected to the cathode guide block 12 through the above-mentioned wire 112. The transmitter device has a lower parasitic inductance, a lower required driving voltage, and a lower overall circuit design difficulty, which can effectively control production costs and product size.

[0080] Furthermore, the present application also provides a laser radar, which may include the above-mentioned transmitting end device and a radar body, and the transmitting end device is installed on the radar body. The laser radar uses the above-mentioned transmitting end device to emit uniform signal light, maintain stable power, and has high ranging accuracy.

[0081] Furthermore, the circuit board assembly of the present application is further introduced below in conjunction with specific examples.

[0082] As shown in the figure, Figures 2 to 4 As shown, in the first example of the present application, the circuit board assembly includes a circuit board 10, a cathode guide block 12, a chip 20, an adhesive layer 30, a plurality of anode connectors and a circuit element 13. The cathode guide block 12 is a copper block, which fills the mounting hole 111 of the circuit board 10. The copper block and the circuit board 10 are integrally formed in one process, which can be understood as being formed by filling the mounting hole 111 of the circuit board 10 with copper material. The anode connector is a gold wire 41, and the anode of the chip 20 is connected to the circuit board through the gold wire 41, and the cathode of the chip 20 is connected to the copper block through the adhesive layer 30.

[0083] The circuit element 13 includes a driving chip and a capacitor. The copper block, the driving chip and the capacitor are connected and conducted through the wire 112 inside the circuit board 10. The driving chip and the capacitor can also be other electronic components that require electrical connection and can be adjusted according to the application.

[0084] The circuit board assembly of the first example is also applicable to chips that do not require electrical connections on the back, such as COMS camera chips. It is only necessary to disconnect the wire 112 connected to the capacitor in the circuit board 10. At this time, the adhesive layer 30 such as LOCTITE ABLESTIK ABP 8068TB can still be used, and the thermal conductivity is 100W / (m·K). Due to the presence of conductive metal in the adhesive layer 30, it has better thermal conductivity than thermal grease. Therefore, the circuit board 10 structure of the present application has good thermal conductivity and good electrical isolation.

[0085] like Figure 1The figure shows the structure of the circuit board assembly of the bonding scheme of the hollow embedded ceramic substrate of the laser radar in the prior art. In the horizontal direction, the gap between the ceramic substrate and the circuit board in the original scheme is greater than or equal to 0.5 mm to prevent collision. The ceramic substrate is removed in the present application. Compared with the prior art, the present application does not require an additional pad in the vertical direction, so the thickness can at least reduce the thickness of the pad, which is more conducive to the development of miniaturization and thinness.

[0086] In one of the embodiments of the present application, the gap between the circuit board 10 and the chip 20 is less than or equal to 0.3 mm, which is conducive to achieving redundancy for glue overflow.

[0087] For example, in terms of the cathode, since the present application uses an adhesive layer 30 to connect the copper block and the chip 20, the width of the adhesive layer 30 is 0.05 cm, and the length of the adhesive layer 30 is 0.4 cm. According to the parasitic inductance formula, L=K×L1 / D=0.09nH.

[0088] In the existing bonding gold wire solution, the width of the bonding gold wire (ie, the diameter of the gold wire) is 1 mil, that is, the diameter D is 0.025 mm, and the length L1 of the wire 112 is 1 mm. According to the parasitic inductance formula, L=K×L1 / D=0.9949nH.

[0089] Therefore, the present application can significantly reduce parasitic inductance.

[0090] like Figure 4 and Figure 5 As shown, in the second example of the present application, the circuit board assembly includes a circuit board 10, a cathode guide block 12, a chip 20, an adhesive layer 30, a plurality of anode connectors, and a circuit element 13. The cathode guide block 12 is a copper block, which half fills the mounting hole 111 of the circuit board 10. The anode connector is a gold wire 41, and the anode of the chip 20 is connected to the circuit board through the gold wire 41, and the cathode of the chip 20 is connected to the copper block through the adhesive layer 30.

[0091] In terms of verticality, the second example reduces the thickness of the chip 20 and the thickness of the adhesive layer 30 compared to the first example, wherein the thickness of the adhesive layer 30 is generally 50 μm, and the thickness of the chip 20 is generally 200 μm. By designing the thickness of the copper block, the upper surface of the circuit board 10 and the upper surface of the chip 20 are flush, so that the gold wire 41 has the shortest design length. For example, if the thickness of the board 11 is 1.5 mm, the thickness of the adhesive layer 30 is 50 μm, and the thickness of the chip 20 is 200 μm, then the thickness of the copper block can be designed to be 1250 μm. In the actual production process, the circuit board 10 can be made into an integrated circuit board 10 with a concave depth of 250 μm by using a boss fixture with a boss thickness of 250 μm.

[0092] The thickness of the adhesive layer 30 can be controlled by calculating the capacity of the adhesive layer based on a thickness of 50 μm. The capacity can be calculated based on the size of the mounting hole 111 remaining after filling the copper block. In addition, in the present application, there is a gap between the circuit board 10 and the chip 20, which can be used to achieve redundancy for adhesive layer overflow. The larger the design gap, the larger the range of adhesive layer overflow.

[0093] like Figure 6 and Figure 8 As shown, in the third example of the present application, the circuit board assembly includes a circuit board 10, a cathode guide block 12, a chip 20, an adhesive layer 30, a plurality of anode connectors and a circuit element 13. The cathode guide block 12 is a copper block, which half fills the mounting hole 111 of the circuit board 10. The anode connector is a copper conductor, which is welded to connect the chip 20 and the circuit board 10 by an automatic carrier welding process. As shown in the figure is a structural diagram of a single pad 21 welded by an automatic carrier welding process. The pad 21 of the chip 20 is generally a circle with a diameter of 80μm. The size of the copper conductor automatically welded by the carrier is 1mm long and 0.05mm wide. After welding, the size of the copper conductor does not exceed 1mm long and 0.05mm wide. And as Figure 5 The figure shows the gold wire 41 welding structure of the circuit board assembly of the second example. The width of the gold wire 41 (i.e., the diameter of the gold wire) is 2.5μm. The electrode leads on the surface of the chip are connected to the outer leads of the substrate or the lead frame by using heat, pressure, and ultrasonic energy to form a gold wire ball 43. Generally, the size of the gold wire ball 43 is 2-3 times the diameter of the gold wire 41, which is 5μm to 7.5μm. If the diameter of the gold wire 41 continues to increase, the size of the gold wire ball 43 will exceed the diameter of the pad 21 of the chip 20, resulting in the spacing between the gold wire balls 43 being too small and there is a risk of short circuit.

[0094] For example, the width of the copper conductor is D = 0.05 mm, and the length of the copper conductor is L1 = 1 mm. According to the parasitic inductance formula, L = K × L1 / D = 0.75 nH.

[0095] In the existing bonding gold wire solution, the diameter of the bonding gold wire is 1 mil, that is, the radius D is 0.025 mm, and the length L1 of the wire 112 is 1 mm. According to the parasitic inductance formula, L=K×L1 / D=0.9949nH.

[0096] Therefore, the parasitic inductance L of the automatic soldering with carrier tape is about 0.75nH, and the parasitic inductance L of the gold wire 41 is about 0.9949nH, which is reduced by about 24.5%. In fact, the width of the pad 21 of the automatic soldering with carrier tape can still be increased, thereby further reducing the parasitic inductance, while the gold wire 41 is usually difficult to increase due to the wire bonding cost and technical limitations.

[0097] The specific parameters of three examples of this application are shown in the following table.

[0098]

[0099] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0100] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A circuit board assembly, characterized in that: include: A circuit board, the circuit board comprising a board body and a cathode guide block, the board body having a mounting hole, the cathode guide block filling the mounting hole and being electrically connected to the board body; A chip, wherein the chip is fixedly mounted on the cathode guide block and the chip is electrically connected to the cathode guide block; as well as At least one anode connector, wherein the anode connector is electrically connected to the chip and the circuit board respectively.

2. The circuit board assembly according to claim 1, characterized in that: The circuit board assembly satisfies the relationship: 10≤L1 / D≤70; Wherein, L1 is the length of the anode connector, and 0.255≤L1≤5mm; D is the width of the anode connector, and 0.01mm≤D≤0.1mm.

3. The circuit board assembly according to claim 1, characterized in that: The circuit board assembly further includes an adhesive layer, which is disposed between the cathode guide block and the chip to fix the chip to the cathode guide block and electrically connect the chip to the cathode guide block.

4. The circuit board assembly according to claim 3, characterized in that: The circuit board assembly satisfies the relationship: 15≤S / d≤1800; Wherein, S is the contact area between the adhesive layer and the chip, and 0.1cm 2 ≤S≤5.5cm 2 ; d is the thickness of the adhesive layer.

5. The circuit board assembly according to claim 3, characterized in that: The circuit board assembly satisfies the relationship: 1.5×10 3 ≤S / (R×d)≤5.5×10 7 ; Wherein, S is the contact area between the adhesive layer and the chip, and 0.1cm 2 ≤S≤5.5cm 2 ; R is the resistance of the adhesive layer, and 10 -6 ≤R≤10 -4 Ω·cm; d is the thickness of the adhesive layer, and 10μm≤d≤80um.

6. The circuit board assembly according to claim 3, characterized in that: The anode connecting member is a gold wire, and two ends of the gold wire are electrically connected to the chip and the board body respectively.

7. The circuit board assembly according to claim 6, characterized in that: The thickness of the cathode guide block is equal to the thickness of the plate body, so that the upper surface of the cathode guide block is flush with the upper surface of the plate body.

8. The circuit board assembly according to claim 6, characterized in that: The thickness of the cathode guide block is smaller than the thickness of the plate body.

9. The circuit board assembly according to claim 8, characterized in that: The circuit board assembly satisfies the relationship: 0.8≤d1 / d2≤1.2, wherein d1 is the difference between the thickness of the cathode guide block and the thickness of the board body, and d2 is the sum of the thickness of the chip and the adhesive layer.

10. The circuit board assembly according to claim 9, characterized in that: The difference d1 between the thickness of the cathode guide block and the thickness of the plate body is in the range of 200 μm to 300 μm, or the sum d2 of the thickness of the chip and the adhesive layer is in the range of 200 μm to 300 μm.

11. The circuit board assembly according to claim 3, characterized in that: The thickness of the cathode guide block is smaller than that of the board body, the upper surface of the chip is flush with the upper surface of the board body, and the anode connector is a metal conductor, and both ends of the metal conductor are respectively welded to the circuit board and the chip.

12. The circuit board assembly according to claim 11, characterized in that: The width D1 of the metal conductor is equal to the diameter of the pad of the chip.

13. The circuit board assembly according to any one of claims 4 to 12, characterized in that: The thickness d of the adhesive layer satisfies the relationship 10 μm≤d≤80 μm.

14. The circuit board assembly according to any one of claims 1 to 12, characterized in that: At least one conducting wire is embedded in the board body, and a plurality of via holes are formed on the board body around the mounting hole. The via holes are used to allow the conducting wire to pass through so as to electrically connect the cathode guide block with other circuit elements fixed on the board body.

15. The circuit board assembly according to any one of claims 1 to 12, characterized in that: The cathode guide block is made of one material or a combination of multiple materials selected from the group consisting of copper, aluminum and silver.

16. The circuit board assembly according to any one of claims 1 to 12, characterized in that: The chip is a VSCEL chip or a CMOS chip.

17. The circuit board assembly according to any one of claims 1 to 12, characterized in that: The number of the anode connectors is between 10 and 300.

18. A transmitting end device, characterized in that: include: A circuit board assembly as claimed in any one of claims 1 to 17; and The circuit element is fixed on the circuit board assembly and electrically connected to the circuit board assembly.

19. A laser radar, characterized in that: include: The transmitting end device as claimed in claim 18; and The radar body, the transmitting end device is installed on the radar body.

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