CN222321835U - Circuit board assembly, transmitter device and lidar - Google Patents
Circuit board assembly, transmitter device and lidar Download PDFInfo
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- CN222321835U CN222321835U CN202422443780.9U CN202422443780U CN222321835U CN 222321835 U CN222321835 U CN 222321835U CN 202422443780 U CN202422443780 U CN 202422443780U CN 222321835 U CN222321835 U CN 222321835U
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- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims abstract description 52
- 239000012790 adhesive layer Substances 0.000 claims abstract description 47
- 239000004020 conductor Substances 0.000 claims description 30
- 229910052751 metal Inorganic materials 0.000 claims description 23
- 239000002184 metal Substances 0.000 claims description 23
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 22
- 229910052802 copper Inorganic materials 0.000 claims description 22
- 239000010949 copper Substances 0.000 claims description 22
- 239000010410 layer Substances 0.000 claims description 11
- 239000000463 material Substances 0.000 claims description 11
- 229910052782 aluminium Inorganic materials 0.000 claims description 10
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 10
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 4
- 229910052709 silver Inorganic materials 0.000 claims description 4
- 239000004332 silver Substances 0.000 claims description 4
- 230000003071 parasitic effect Effects 0.000 abstract description 32
- 239000010931 gold Substances 0.000 abstract description 14
- 229910052737 gold Inorganic materials 0.000 abstract description 14
- 230000000694 effects Effects 0.000 description 14
- 239000000758 substrate Substances 0.000 description 14
- 238000000034 method Methods 0.000 description 9
- 230000008569 process Effects 0.000 description 9
- 238000005476 soldering Methods 0.000 description 8
- 239000000919 ceramic Substances 0.000 description 7
- 230000017525 heat dissipation Effects 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- 229910000679 solder Inorganic materials 0.000 description 7
- 238000013461 design Methods 0.000 description 5
- 239000003990 capacitor Substances 0.000 description 4
- 241000218202 Coptis Species 0.000 description 3
- 235000002991 Coptis groenlandica Nutrition 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
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- 238000004891 communication Methods 0.000 description 1
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
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- Semiconductor Lasers (AREA)
Abstract
The utility model relates to a circuit board assembly, a transmitting end device and a laser radar, wherein the circuit board assembly comprises a circuit board and a plurality of anode connecting pieces, the circuit board comprises a board body and a cathode guide block, the board body is provided with a mounting hole, the cathode guide block is filled in the mounting hole and is electrically connected with the board body, a chip, an adhesive layer is arranged between the cathode guide block and the chip to fixedly arrange the chip on the cathode guide block and electrically connect the chip with the cathode guide block, and the anode connecting pieces are respectively electrically connected with the chip and the circuit board. The cathode of the circuit board component does not use gold wires, so that the number of the gold wires can be reduced, and the parasitic inductance can be reduced.
Description
Technical Field
The utility model relates to the technical field of laser radars, in particular to a circuit board assembly, a transmitting end device and a laser radar.
Background
Along with the development of the laser radar technology, a laser radar product transmitting end module gradually develops to a high-power, high-current and narrow-pulse laser (Vcsel), so that when a circuit board scheme of the laser radar product is designed, the problems of heat dissipation and electric performance such as laser narrow pulse and waveform are required to be solved.
In the bonding scheme of the currently marketed laser radar popular hollowed-out embedded ceramic substrate, as shown in fig. 1, the scheme bonds a circuit board A1 to an aluminum-based substrate A2 through a conductive adhesive layer A7, bonds a ceramic substrate A3 to the aluminum-based substrate A2 through a conductive adhesive layer A8, bonds a narrow pulse laser A4 to the ceramic substrate A3 through the conductive adhesive layer A7, and conducts an anode and a cathode of the narrow pulse laser with the circuit board A1 respectively by utilizing an anode gold wire A5 and a cathode gold wire A6.
This scheme can cause the problem of bonding gold thread's length overlength and the too big problem of internal resistance and parasitic inductance that the gold thread brought, because the parasitic inductance that uses the gold thread is great, driving voltage needs doubly to increase for partial laser promotes to 100V from 50V's driving voltage, thereby make the design degree of difficulty of circuit board scheme increase, design wiring and interval also increase to some extent, lead to the promotion of manufacturing cost and product size, the laser pulse waveform has been influenced and certain pressure drop has been produced, cause the laser radar transmitting end to give out light unevenly, power reduces, range finding precision reduces, lead to laser radar's performance to drop.
Disclosure of utility model
Based on this, it is necessary to provide a circuit board assembly, a transmitting end device and a lidar aiming at the problem of excessive parasitic inductance of gold wires of the existing lidar products.
A circuit board assembly, comprising:
the circuit board comprises a board body and a cathode guide block, wherein 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 fixedly arranged on the cathode guide block and electrically connected with the cathode guide block, and
And at least one anode connecting piece, wherein the anode connecting piece is electrically connected with the chip and the circuit board respectively.
In one embodiment, the circuit board assembly satisfies the relationship 10.ltoreq.L1/D.ltoreq.70;
Wherein L1 is the length of the anode connecting piece, L1 is more than or equal to 0.255 and less than or equal to 5mm, D is the width of the anode connecting piece, and D is more than or equal to 0.01mm and less than or equal to 0.1mm.
In one embodiment, the circuit board assembly further includes an adhesive layer disposed between the cathode guide block and the chip to secure the chip to the cathode guide block and electrically connect the chip to the cathode guide block.
In one embodiment, the circuit board assembly satisfies the relationship 15.ltoreq.S/d.ltoreq.1800;
Wherein S is the contact area between the bonding layer and the chip, and 0.1cm 2≤S≤5.5cm2, and d is the thickness of the bonding layer.
In one embodiment, the circuit board assembly satisfies the relationship 1.5X10 3≤S/(R×d)≤5.5×107;
Wherein S is the contact area between the bonding layer and the chip, and is 0.1cm 2≤S≤5.5cm2, R is the resistance of the bonding layer, and is 10 -6≤R≤10-4 Ω & cm, d is the thickness of the bonding layer, and d is more than or equal to 10 μm and less than or equal to 80 μm.
In one embodiment, the anode connecting piece is a gold wire, and two ends of the gold wire are respectively and electrically connected to the chip and the plate body.
In one embodiment, the thickness of the cathode guide block is equal to the thickness of the plate body such that the upper surface of the cathode guide block is flush with the upper surface of the plate body.
In one embodiment, the thickness of the cathode guide block is less than the thickness of the plate body.
In one embodiment, the circuit board assembly satisfies the relation of 0.8.ltoreq.d1/d2.ltoreq.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 thicknesses of the chip and the adhesive layer.
In one embodiment, the difference d1 between the thickness of the cathode guide and the thickness of the plate body is in the range of 200 μm to 300 μm, or the sum d2 of the thicknesses of the chip and the adhesive layer is in the range of 200 μm to 300 μm.
In one embodiment, the thickness of the cathode guide block is smaller than that of the plate body, the upper surface of the chip is flush with the upper surface of the plate body, the anode connecting piece is a metal conductor, and two ends of the metal conductor are welded to the circuit board and the chip respectively.
In one embodiment, the width D1 of the metal conductor is equal to the diameter of the bond pad of the chip.
In one embodiment, the thickness d of the adhesive layer satisfies the relationship 10 μm.ltoreq.d.ltoreq.80 μm.
In one embodiment, at least one wire is embedded in the board body, a plurality of through holes are formed in the periphery of the mounting hole in the board body, and the through holes are used for enabling the wire to pass through so as to electrically connect the cathode guide block with other circuit elements fixedly arranged on the board body.
In one embodiment, the material of the cathode guide block is one or a combination of copper, aluminum and silver.
In one embodiment, the chip is a VSCEL chip or a CMOS chip.
In one embodiment, the number of anode connectors is between 10 and 300.
A transmitting end apparatus comprising:
a circuit board assembly as claimed in any one of the preceding claims, and
The circuit element is fixedly arranged on the circuit board assembly and is electrically connected with the circuit board assembly.
A lidar, comprising:
A transmitting end unit as claimed in any one of the preceding claims, and
And the transmitting end device is arranged on the radar main body.
The circuit board assembly uses the cathode guide block as the substrate of the chip, and an aluminum-based substrate required by the traditional chip can be removed, so that the overall size of the circuit board assembly can be greatly reduced, and the miniaturization of the laser radar is realized. The chip is adhered to the cathode guide block through the adhesive layer, so that gold wires are not used for the cathode of the chip, the number of gold wires of the circuit board assembly is reduced, parasitic inductance is reduced, and the circuit board assembly has good heat radiation performance.
Drawings
FIG. 1 is a schematic view of the structure and dimensions of a circuit board assembly of a bonding scheme of a hollowed-out embedded ceramic substrate of a laser radar in the prior art;
Fig. 2 is a schematic structural view of a circuit board assembly according to a first example of the present application;
fig. 3 shows a schematic top view of a circuit board assembly according to the first example of the application described above;
Fig. 4 is a schematic structural view of a circuit board assembly according to a second example of the present application;
Fig. 5 shows a schematic diagram of soldering of gold wires of the above-described second example of the circuit board assembly according to the present application;
fig. 6 is a schematic structural view of a circuit board assembly according to a third example of the present application;
Fig. 7 shows a schematic top view of a circuit board assembly according to the above third example of the application;
fig. 8 shows a schematic soldering view of a metal conductor of the above-described third example of the circuit board assembly according to the present application.
Reference numerals 10, circuit board, 11, board body, 111, mounting hole, 112, wire, 113, via hole, 114, solder strip, 12, cathode guide block, 13, circuit element, 20, chip, 21, bonding pad, 30, adhesive layer, 41, gold wire, 42, metal conductor, 43, gold wire ball.
Detailed Description
In order that the above objects, features and advantages of the utility model will be readily understood, a more particular description of the utility model will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present utility model. The present utility model may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the utility model, whereby the utility model is not limited to the specific embodiments disclosed below.
In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present utility model.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present utility model, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the present utility model, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed, mechanically connected, electrically connected, directly connected, indirectly connected through an intervening medium, or in communication between two elements or in an interaction relationship between two elements, unless otherwise explicitly specified. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.
In the present utility model, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.
It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.
Based on the problem that the parasitic inductance of gold wires of the existing laser radar products is overlarge, the application provides a circuit board assembly. The cathode of the circuit board component does not use gold wires, so that the number of the gold wires can be reduced, and the parasitic inductance can be reduced.
Specifically, referring to fig. 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 electrically connected to the board body 11, the chip 20 is fixedly arranged on the cathode guide block 12, and the chip 20 is electrically connected to the cathode guide block 12. The anode connection is electrically connected to the chip 20 and the circuit board 10, respectively.
It will be appreciated that the circuit board assembly utilizes the cathode guide block 12 as a substrate for the chip 20, and the aluminum-based substrate required for the conventional chip 20 can be removed, so that the overall size of the circuit board assembly can be greatly reduced, and the laser radar can be miniaturized. The chip 20 is adhered to the cathode guide block 12 by the adhesive layer 30, so that the gold wires 41 are not used for the cathode of the chip 20, the number of the gold wires 41 of the circuit board assembly is reduced, the generation of parasitic inductance is reduced, and the circuit board assembly has good heat dissipation performance.
More specifically, in some embodiments, the circuit board assembly satisfies the relationship 10.ltoreq.L1/D.ltoreq.70, where L1 is the length of the anode connection and 0.255.ltoreq.L1.ltoreq.5 mm, D is the width of the anode connection and 0.01 mm.ltoreq.D.ltoreq.0.1 mm.
The parasitic inductance of a single anode connection can be calculated by the relationship l=kxl1/D, where K is the proportionality coefficient of the parasitic inductance, k=0.001 to 0.008.
According to the above relation, the parasitic inductance is related to the length and width of the anode connector, and by controlling the length and width of the anode connector, the parasitic inductance can be effectively reduced, and the shorter the length of the anode connector, the longer the width, the smaller the parasitic inductance, and the longer the length of the anode connector, the shorter the width, and the larger the parasitic inductance. Preferably, the circuit board assembly further satisfies the relation of L1/D less than or equal to 10 and less than or equal to 50, and the length of the anode connecting piece further satisfies L1 less than or equal to 0.255 and less than or equal to 1.25mm, and preferably has better effect.
Further, in one embodiment, the circuit board assembly further includes an adhesive layer 30, the adhesive layer 30 having good electrical and thermal conductivity, and being capable of fixing the chip 20 to the cathode lead 12 and electrically connecting the chip 20 to the cathode lead 12.
Preferably, in one embodiment, the circuit board assembly satisfies the relation 15.ltoreq.S/d.ltoreq.1800, where S is the contact area between the adhesive layer 30 and the chip 20, and 0.1cm 2≤S≤5.5cm2, preferably, S further satisfies the relation 0.1cm 2≤S≤0.25cm2, and d is the thickness of the adhesive layer 30. The circuit board assembly satisfies the above relation, so that the adhesive layer 30 can have good electrical conductivity and thermal conductivity, and can transfer heat of the chip 20 while ensuring formation of an electrical circuit, thereby achieving a heat dissipation effect.
Preferably, the application field of the circuit board assembly is not limited, and the range of the optimal effect is different according to the different application fields of the circuit board assembly, and when the circuit board assembly is applied to the laser radar field, the circuit board assembly has the optimal effect in the range of 15-300S/d and 0.1cm 2≤S≤0.9cm2, when the circuit board assembly is applied to the camera module field, the circuit board assembly has the optimal effect in the range of 40-180S/d and 0.3cm 2≤S≤0.5cm2, when the circuit board assembly is applied to the car light field, the circuit board assembly has the optimal effect in the range of 420-1800S/d and 3cm 2≤S≤5.5cm2, and when the circuit board assembly is applied to the head-up display field, the circuit board assembly has the optimal effect in the range of 320-1300S/d and 2cm 2≤S≤4cm2.
Preferably, in one embodiment, the circuit board assembly satisfies the relationship 1.5X10 3≤S/(R×d)≤5.5×107, where S is the area of the adhesive layer 30 and 0.1cm 2≤S≤5.5cm2, R is the resistance of the adhesive layer 30 and 10 -6≤R≤10-4 Ω cm, and d is the thickness of the adhesive layer 30 and 10 μm d is 80 μm. By controlling the area and thickness of the adhesive layer 30, the adhesive layer 30 can be made to have good electrical conductivity and thermal conductivity, and heat of the chip 20 can be transferred out while ensuring formation of an electrical circuit, thereby achieving a heat dissipation effect. Preferably, the circuit board assembly further satisfies the relation of 2×10 3≤S/(R×d)≤8×106, and has more technical effects.
More preferably, the application field of the circuit board assembly of the present application is not limited, and the range of the optimal effect is different according to the application field of the circuit board assembly, and as an example, the circuit board assembly has the optimal effect in the range of 1.5×10 3≤S/(R×d)≤9×108 when the circuit board assembly is applied to the laser radar field, the circuit board assembly has the optimal effect in the range of 4.3×10 3≤S/(R×d)≤5.18×108 when the circuit board assembly is applied to the camera module field, the circuit board assembly has the optimal effect in the range of 4.4×10 6≤S/(R×d)≤5.3×109 when the circuit board assembly is applied to the car light field, and the circuit board assembly has the optimal effect in the range of 3.2×10 6≤S/(R×d)≤4×109 when the circuit board assembly is applied to the head-up display field.
It is noted that the circuit board assembly also satisfies the relationship M=k×S/(R×d), where k is the coefficient of proportionality of electrothermal performance, k=10++9, M is the electrothermal performance of the adhesive layer 30, and M is 0.3.ltoreq.M.ltoreq.2.
Alternatively, in some embodiments, the circuit board assembly may have the cathode guide block 12 embedded in the mounting hole 111 of the circuit board 10 by a one-time molding process. The cathode guide 12 may 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 connection member may be a gold wire 41 or other conductor connection member such as a metal conductor 42. When the gold wire 41 is used as the anode, the gold wire 41 may be soldered to the solder tape 114 of the circuit board 10 and the pad 21 of the chip 20 by using a bonding gold wire process, and when the metal conductor 42 is used as the anode, the metal conductor 42 may be soldered to the solder tape 114 of the circuit board 10 and the pad 21 of the chip 20 by using a carrier tape automatic soldering process.
It is noted that the width D of the anode connection may be the diameter of the gold wire 41 or the width of the metal conductor 42 on the bonding pad 21 of the chip 20.
Alternatively, as shown in fig. 2 and 3, in one embodiment, the anode connector is a gold wire 41, and two ends of the gold wire 41 are electrically connected to the chip 20 and the board 11, respectively. The cathode guide 12 fills the circuit board 10. The thickness of the cathode guide 12 is equal to the thickness of the board body 11 so that the upper surface of the cathode guide 12 is flush with the upper surface of the board body 11. I.e. the cathode guide 12 fills the mounting hole 111 of the circuit board 10. By the arrangement, the production process of the circuit board assembly is simpler, and the production efficiency is higher.
Alternatively, as shown in fig. 4, in one embodiment, the anode connector is a gold wire 41, and 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 12 is smaller than the thickness of the plate 11. I.e. the cathode guide 12 half fills the mounting hole 111 of the circuit board 10. Thus, the value of d1 is controlled during the process of filling the cathode guide block 12, the value of d2 is controlled during the process of plating the 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.
Preferably, in one embodiment, the circuit board assembly satisfies the relationship 0.8.ltoreq.d1/d2.ltoreq.1.2, where d1 is the difference between the thickness of the cathode guide 12 and the thickness of the board 11, and d2 is the sum of the thicknesses of the chip 20 and the adhesive layer 30.
More preferably, in one of the embodiments, the difference d1 between the thickness of the cathode guide 12 and the thickness of the plate 11 ranges from 200 μm to 300 μm, or the sum d2 of the thicknesses of the chip 20 and the adhesive layer 30 ranges from 200 μm to 300 μm. By this arrangement, the length of the gold wire 41 can be minimized, and the generation of parasitic inductance can be further reduced.
Further, in one embodiment, the thickness d of the adhesive layer 30 is 80 μm or less. By controlling the thickness of the adhesive layer 30, the length of the gold wires 41 can be controlled, and the minimum length of the gold wires 41 can be realized, so that parasitic inductance is minimized.
Alternatively, as shown in fig. 6 and 7, in one embodiment, the thickness of the cathode guide 12 is smaller than the thickness of the board 11, the upper surface of the chip 20 is flush with the upper surface of the board 11, the anode connector is a metal conductor 42, and two ends of the metal conductor 42 are soldered to the circuit board 10 and the chip 20, respectively. I.e. the cathode guide 12 half fills the mounting hole 111 of the circuit board 10. Since the metal conductor 42 can be directly soldered to the solder tape 114 of the circuit board 10 and the solder pad 21 of the chip 20 by a carrier tape automatic soldering process, no solder balls are generated, and thus the width of the metal conductor 42 is not limited by the size of the solder balls, but the width of the metal conductor 42 is generally larger than the diameter of the gold wire 41, so that the thickness of the anode connector can be increased, as known by the parasitic inductance formula l=kxl1/D, where 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, and therefore, the larger the width of the metal conductor 42, the smaller the parasitic inductance, and the further the parasitic inductance can be reduced by the metal conductor 42 structure.
Preferably, as shown in fig. 8, in one embodiment, the width D1 of the metal conductor 42 is equal to the diameter of the bond pad 21 of the die 20. By this arrangement, the width of the metal conductor 42 is maximized, and parasitic inductance can be minimized.
The metal conductor 42 may be a copper conductor, for example.
It should be noted that, when the carrier tape automatic welding process is used, a standardized tape (most often 100 m) can be used, so that the bonding of a plurality of welding spots between the chip of the chip 20 and the lead frame of the circuit board 10 is realized, the bonding speed is high, the production efficiency is high, and the industrial mass production is easier to realize.
Further, as shown in fig. 2, in one embodiment, the board 11 has a plurality of wires 112 embedded therein, the board 11 has a plurality of through holes 113 formed around the mounting hole 111, and the through holes 113 are used for passing the wires 112 to electrically connect the cathode guide block 12 with other circuit elements fixed on the board 11. By providing the plurality of through holes 113 on the circuit board 10, the cathode guide block 12 and the circuit element 13 are conducted by the through holes 113 and the wires 112, so that the electric connection is realized, the volume of the circuit board assembly is reduced, and the electric conductivity and the stability can be improved.
Alternatively, in one embodiment, the material of the cathode guide block 12 is a conductive material having a thermal conductivity greater than 190 mW/(mK). By adopting the arrangement, the heat dissipation capability of the circuit board assembly can be enhanced by utilizing the good heat conductivity of the material of the cathode guide block 12, and the heat dissipation problem of the laser radar can be solved.
Alternatively, in one embodiment, the material of the cathode guide 12 is one or a combination of materials from the group consisting of copper, aluminum, and silver. Copper, aluminum and silver materials have good heat conducting properties and contribute to enhancing the heat dissipation capacity of the circuit board assembly. Wherein the thermal conductivity of the copper material is 398W/(mK), and the thermal conductivity of the aluminum is 238W/(mK). Compared with the main aluminum materials on the market, aluminum oxide Al 2O3 (with the heat conductivity of 25W/(m.K)) and aluminum nitride AlN (with the heat conductivity of 170W/(m.K)) have better heat conducting performance.
Alternatively, in one embodiment, the chip 20 includes, but is not limited to, a VSCEL chip or a CMOS chip. The LED light source can also be a SPAD chip, a matrix pixel lamp chip, an LED chip, an LD chip, a DMD chip, an LCOS chip and an MEMS chip, wherein the chips have different functions under different applications, such as not only emitting light beams but also receiving light beams under the application of a laser radar or a vehicle-mounted camera, but also emitting light beams and reflecting light beams under the application of a car lamp or head-up display, and particularly can realize different functions according to different applications.
Optionally, in some embodiments, the number of anode connectors is between 10 and 300. The total parasitic inductance of the circuit board assembly of the present application can be calculated from the number n of anode connections in combination with the relation l=n×k×l1/D.
Further, the application also provides a transmitting end device, which comprises the circuit board assembly and a circuit element, wherein the circuit element 13 is fixedly arranged on the circuit board assembly and is electrically connected with the circuit board assembly. The circuit element 13 may include a circuit element 13 necessary for driving a chip, a capacitor, or the like, and the circuit element 13 may be electrically connected to the cathode lead 12 through the above-mentioned wire 112. The transmitting end device has lower parasitic inductance, lower required driving voltage and lower design difficulty of the whole circuit scheme, and can effectively control the production cost and the product size.
Further, the application also provides a laser radar, which can comprise the transmitting end device and a radar main body, wherein the transmitting end device is arranged on the radar main body. The laser radar can emit uniform signal light by using the emitting end device, can keep stable power and has higher ranging precision.
Further, the circuit board assembly of the present application is further described below in connection with specific examples.
As shown in fig. 2 to 4, in the first example of the present application, the circuit board assembly includes a circuit board 10, a cathode lead 12, a chip 20, an adhesive layer 30, a plurality of anode connectors, and a circuit element 13. The cathode guide 12 is a copper block that fills the mounting hole 111 of the circuit board 10, and the copper block and the circuit board 10 are integrally formed by one-step processing, which can be understood as being formed by filling copper material into the mounting hole 111 of the circuit board 10. The anode connection is a gold wire 41, 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.
The circuit element 13 includes a driving chip and a capacitor, which are connected and conducted by a wire 112 inside the circuit board 10, and the driving chip and the capacitor may be other electronic components that need to be electrically connected, and may be adjusted according to the application.
The circuit board assembly of the first example is also suitable for chips such as cmos camera chips that do not need to have electrical connection on the back of the chip, and only needs to disconnect the conductive wires 112 connected to the capacitor in the circuit board 10, where the adhesive layer 30, such as LOCTITE ABLESTIK ABP 8068TB, may still be used, and the thermal conductivity is 100W/(m·k), and because the conductive metal exists in the adhesive layer 30, the circuit board 10 structure of the present application has better thermal conductivity than the conductive silicone grease, and therefore, has good electrical isolation under the condition of good thermal conductivity.
As shown in fig. 1, in the prior art, the structure of the circuit board assembly of the bonding scheme of the hollow embedded ceramic substrate of the laser radar is shown, in the horizontal direction, the gap between the ceramic substrate and the circuit board in the prior scheme is more than or equal to 0.5mm to prevent collision, but the ceramic substrate is removed, and compared with the prior art, the application does not need an additional backing plate in the vertical direction, so that the thickness of the backing plate can be at least reduced, and the application is more beneficial to the development of miniaturization, light weight and thinning.
In one embodiment of the present application, the clearance between the circuit board 10 and the chip 20 is less than or equal to 0.3mm, which is beneficial to realizing redundancy of glue overflow.
For example, in the cathode aspect, since the present application adopts the adhesive layer 30 to connect the copper block and the chip 20, the width of the adhesive layer 30 is 0.05cm, the length of the adhesive layer 30 is 0.4cm, and l=kxl1/d=0.09 nH according to the parasitic inductance formula.
In the existing bonding gold wire scheme, the width of the bonding gold wire (i.e. the diameter of the gold wire) is 1mil, i.e. the diameter D is 0.025mm, the length L1 of the wire 112 is 1mm, and l=kxl 1/d=0.9949 nH according to the parasitic inductance formula.
Therefore, the application can greatly reduce parasitic inductance.
As shown in fig. 4 and 5, in a second example of the present application, the circuit board assembly includes a circuit board 10, a cathode lead 12, a chip 20, an adhesive layer 30, a plurality of anode connectors, and a circuit element 13. The cathode guide 12 is a copper block that half fills the mounting hole 111 of the circuit board 10. The anode connection is a gold wire 41, 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.
In terms of the vertical direction, 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 to the adhesive layer 30 is generally 50 μm and the thickness of the chip 20 is generally 200 μm, and the upper surface of the circuit board 10 and the upper surface of the chip 20 are made flush by designing the thickness of the copper block so that the gold wires 41 have the shortest design length. For example, the thickness of the plate 11 is 1.5mm, the thickness of the adhesive layer 30 is 50 μm, and the thickness of the chip 20 is 200 μm, and then the thickness of the copper block may be 1250 μm. In the actual production process, the circuit board 10 can be manufactured into an integrated circuit board 10 with a concave shape of 250 μm through a boss jig with a boss thickness of 250 μm.
The thickness of the adhesive layer 30 can be controlled by calculating the capacity of the adhesive layer according to the thickness of 50 μm, the capacity can be calculated according to the size of the mounting hole 111 remained after the copper block is filled, and the gap exists between the circuit board 10 and the chip 20, so that the redundancy of the overflow of the adhesive layer can be realized, and the larger the design gap is, the larger the overflow range of the adhesive layer is.
As shown in fig. 6 and 8, in a third example of the present application, the circuit board assembly includes a circuit board 10, a cathode lead 12, a chip 20, an adhesive layer 30, a plurality of anode connectors, and a circuit element 13. The cathode guide 12 is a copper block that half fills the mounting hole 111 of the circuit board 10. The anode connection member is a copper conductor, and the chip 20 and the circuit board 10 are welded and connected through a carrier tape automatic welding process. As shown in the figure, which is a structural diagram of a carrier tape automated soldering process for soldering a single bonding pad 21, the bonding pad 21 of the chip 20 is generally circular with a diameter of 80 μm, the size of a carrier tape automated soldered copper conductor is 1mm long and 0.05mm wide, and the size of the copper conductor after soldering does not exceed 1mm long and 0.05mm wide. As shown in fig. 5, which shows a gold wire 41 soldering structure of the circuit board assembly of the second example, the gold wire 41 has a width (i.e. the diameter of the gold wire) of 2.5 μm, the electrode leads on the surface of the chip are connected with the outer leads of the substrate or the lead frame by using heat, pressure and ultrasonic energy, and then gold wire balls 43 are formed, the size of the gold wire balls 43 is generally 2-3 times the diameter of the gold wire 41, and is 5 μm to 7.5 μm, if the diameter of the gold wire 41 is continuously increased, the size of the gold wire balls 43 exceeds the diameter of the bonding pads 21 of the chip 20, and the spacing between the gold wire balls 43 is too small, so that there is a risk of short circuit.
For example, the width d=0.05 mm of the copper conductor, the length l1=1 mm of the copper conductor, l=k×l1/d=0.75 nH according to the parasitic inductance formula.
In the existing bonding wire scheme, the diameter of the bonding wire is 1mil, namely the radius D is 0.025mm, the length L1 of the wire 112 is 1mm, and l=kxl 1/d=0.9949 nH according to the parasitic inductance formula.
Therefore, the parasitic inductance L of the carrier tape automatic bonding is about 0.75nH, the parasitic inductance L of the gold wire 41 is about 0.9949nH, and about 24.5% decrease is achieved, and actually the width of the bonding pad 21 of the carrier tape automatic bonding can be increased, so as to further reduce the parasitic inductance, and the gold wire 41 is generally difficult to increase due to the limitation of the wire bonding cost and the technology.
Three exemplary specific parameters of the present application are shown in the following table.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the utility model, which are described in detail and are not to be construed as limiting the scope of the utility model. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the utility model, which are all within the scope of the utility model. Accordingly, the scope of protection of the present utility model is to be determined by the appended claims.
Claims (19)
1. A circuit board assembly, comprising:
the circuit board comprises a board body and a cathode guide block, wherein 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 fixedly arranged on the cathode guide block and electrically connected with the cathode guide block, and
And at least one anode connecting piece, wherein the anode connecting piece is electrically connected with the chip and the circuit board respectively.
2. The circuit board assembly of claim 1, wherein the circuit board assembly satisfies the relationship 10.ltoreq.L1/D.ltoreq.70;
Wherein L1 is the length of the anode connecting piece, L1 is more than or equal to 0.255 and less than or equal to 5mm, D is the width of the anode connecting piece, and D is more than or equal to 0.01mm and less than or equal to 0.1mm.
3. The circuit board assembly of claim 1, further comprising an adhesive layer disposed between the cathode lead and the chip to secure the chip to the cathode lead and electrically connect the chip to the cathode lead.
4. The circuit board assembly of claim 3, wherein the circuit board assembly satisfies the relationship 15.ltoreq.S/d.ltoreq.1800;
Wherein S is the contact area between the bonding layer and the chip, and 0.1cm 2≤S≤5.5cm2, and d is the thickness of the bonding layer.
5. The circuit board assembly of claim 3, wherein the circuit board assembly satisfies the relationship 1.5 x 10 3≤S/(R×d)≤5.5×107;
Wherein S is the contact area between the bonding layer and the chip, and is 0.1cm 2≤S≤5.5cm2, R is the resistance of the bonding layer, and is 10 -6≤R≤10-4 Ω & cm, d is the thickness of the bonding layer, and d is more than or equal to 10 μm and less than or equal to 80 μm.
6. The circuit board assembly of claim 3, wherein the anode connection member is a gold wire, and both ends of the gold wire are electrically connected to the chip and the board body, respectively.
7. The circuit board assembly of claim 6, wherein the thickness of the cathode guide block is equal to the thickness of the board body such that an upper surface of the cathode guide block is flush with an upper surface of the board body.
8. The circuit board assembly of claim 6, wherein the thickness of the cathode guide block is less than the thickness of the board body.
9. The circuit board assembly of claim 8, wherein the circuit board assembly satisfies the relationship 0.8.ltoreq.d1/d2.ltoreq.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 thicknesses of the chip and the adhesive layer.
10. The circuit board assembly of claim 9, wherein a difference d1 between a thickness of the cathode guide block and a thickness of the board body ranges from 200 μm to 300 μm, or a sum d2 of thicknesses of the chip and the adhesive layer ranges from 200 μm to 300 μm.
11. The circuit board assembly of claim 3, wherein the thickness of the cathode guide block is less than the thickness of the board body, the upper surface of the chip is flush with the upper surface of the board body, the anode connecting member is a metal conductor, and both ends of the metal conductor are welded to the circuit board and the chip, respectively.
12. The circuit board assembly of claim 11, wherein the width D1 of the metal conductor is equal to a diameter of a bond pad of the chip.
13. The circuit board assembly according to any one of claims 4 to 12, wherein the thickness d of the adhesive layer satisfies the relation 10 μm +.d +.80 μm.
14. The circuit board assembly of any one of claims 1 to 12, wherein at least one wire is embedded in the board body, the board body being provided with a plurality of vias around the mounting holes for passing the wire therethrough to electrically connect the cathode guide block with other circuit elements secured to the board body.
15. The circuit board assembly of any one of claims 1 to 12, wherein the material of the cathode guide block is one or a combination of materials of copper, aluminum, and silver.
16. The circuit board assembly according to any one of claims 1 to 12, wherein the chip is a VSCEL chip or a CMOS chip.
17. The circuit board assembly according to any one of claims 1 to 12, wherein the number of anode connectors is between 10 and 300.
18. A transmitting-end apparatus, comprising:
the circuit board assembly of any one of claims 1 to 17, and
The circuit element is fixedly arranged on the circuit board assembly and is electrically connected with the circuit board assembly.
19. A laser radar which comprises a laser beam source, characterized by comprising the following steps:
The transmitting end unit according to claim 18, and
And the transmitting end device is arranged on the radar main body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202422443780.9U CN222321835U (en) | 2024-10-10 | 2024-10-10 | Circuit board assembly, transmitter device and lidar |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202422443780.9U CN222321835U (en) | 2024-10-10 | 2024-10-10 | Circuit board assembly, transmitter device and lidar |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN222321835U true CN222321835U (en) | 2025-01-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202422443780.9U Active CN222321835U (en) | 2024-10-10 | 2024-10-10 | Circuit board assembly, transmitter device and lidar |
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| Country | Link |
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| CN (1) | CN222321835U (en) |
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2024
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