CN211909274U

CN211909274U - Multilayer printed circuit board

Info

Publication number: CN211909274U
Application number: CN202020406214.XU
Authority: CN
Inventors: 刘维丽; 张海滨
Original assignee: Foshan Feixi Robot Technology Co ltd
Current assignee: Foshan Feixi Robot Technology Co ltd
Priority date: 2020-03-26
Filing date: 2020-03-26
Publication date: 2020-11-10
Anticipated expiration: 2030-03-26

Abstract

The utility model relates to a multilayer printed circuit board, which comprises a first board surface, a second board surface, a third board surface and a fourth board surface which are arranged in sequence, wherein, the first board surface and the second board surface are respectively provided with a wire layer, and the first board surface is communicated with the second board surface through a first guide hole; the fourth face and the first face are communicated through the second guide hole, and the third face and the fourth face are flat copper faces except the position corresponding to the second guide hole. The multilayer printed circuit board comprises a plurality of layers of core boards which are sequentially stacked, in order to better realize the function of a product, metal wiring and components are arranged on the top core board, and the bottom core board is a flat copper plate except the joint with the top core board, so that the bottom layer can be flatly laid on the metal plate, and the connection stability of the circuit board and the metal plate is ensured; the design ensures that the contact part of the circuit board and the metal piece has no any trace or via hole and only has a complete GND plane, thereby eliminating the possibility of short circuit.

Description

Multilayer printed circuit board

Technical Field

The utility model relates to an electronic components field especially relates to a multilayer printed circuit board.

Background

The robot joint is provided with a magnetic encoder, and the magnetic encoder is used for detecting the rotation position information of the robot joint. According to the sampling principle of a magnetic encoder, in order to effectively acquire position information, the magnetic sensor and a magnetic disk need to be kept at a horizontal and reasonable distance as much as possible, so that the magnetic sensor can obtain a strong magnetic field intensity in the rotation process of the following motor.

In actual installation, a circuit board connected with a magnetic encoder needs to be fixed on a horizontal metal plate, however, because a plurality of necessary guide holes and wires exist on the contact surface of the circuit board and the metal plate, when the fixing hole position of the circuit board is tightly fixed with the metal plate, the possibility that a guide hole signal is communicated with the metal plate exists, so that a short circuit phenomenon is generated between the circuit board and the metal plate, and the stability of a product is further influenced.

SUMMERY OF THE UTILITY MODEL

Accordingly, a multilayer printed circuit board is provided to solve the problem that a short circuit is easily generated after a circuit board of a magnetic encoder is fixed to a metal plate.

A multilayer printed circuit board comprises a first board surface, a second board surface, a third board surface and a fourth board surface which are sequentially arranged, wherein the first board surface and the second board surface are respectively provided with a wire layer, and the first board surface is communicated with the second board surface through a first guide hole; the fourth board surface is communicated with the first board surface through a second guide hole, and the third board surface and the fourth board surface are flat copper surfaces except the position corresponding to the second guide hole.

The first core plate is formed by the first plate surface and the second plate surface, and the second core plate is formed by the third plate surface and the fourth plate surface; the first core board, the insulating interlayer and the second core board are sequentially stacked.

The second plate surface and the third plate surface form an intermediate core plate; the first plate surface, the first partition plate, the middle core plate, the second partition plate and the fourth plate surface are sequentially stacked.

Further, the first separator and the second separator include a prepreg.

Further, a connector port for connecting an external device is provided on the fourth board surface.

Further, the connector port is disposed at a position corresponding to the second guide hole.

Furthermore, grounding ends are arranged on the third board surface and the fourth board surface.

Further, the ground terminal is disposed at a position corresponding to the third plate surface and the fourth plate surface.

Further, the first guide hole and/or the second guide hole include a resin filler therein.

Further, still include the solder resist, the solder resist sets up first face and/or on the fourth face, solder resist thickness is between 15um-30 um.

The multilayer printed circuit board comprises a plurality of layers of core boards which are sequentially stacked, wherein the top of each core board is communicated with a magnetic encoder, and the bottom of each core board is arranged on a metal plate; the design ensures that the contact part of the circuit board and the metal piece has no any trace or via hole and only has a complete GND plane, thereby eliminating the possibility of short circuit. The multilayer printed circuit board provided by the application has the advantages of simple structure and easiness in processing, can effectively solve the insulating property between the circuit board and the metal plate, and can also greatly improve the smoothness between the magnetic sensor and the magnetic disk.

Various specific structures of the present application, as well as the functions and effects thereof, will be described in further detail below with reference to the accompanying drawings.

Drawings

FIG. 1 is a schematic view of an assembly of a multi-layer printed circuit board according to a first embodiment of the present application;

FIG. 2 is a schematic view of a multi-layer printed circuit board according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of a multilayer printed circuit board according to a second embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be further clearly and completely described below with reference to the accompanying drawings, but it should be noted that the following embodiments are only some preferred embodiments in the present application, and do not refer to all embodiments covered by the technical solutions of the present application.

It should be noted that when an element is referred to as being "fixed" to another element in the description of the present application, it may 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.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the design of a robot joint, rotational position information of the robot joint is detected by a magnetic encoder. The technical problem that this application will be solved is to the problem that produces the short circuit easily after the circuit board of magnetic encoder is fixed with the metal sheet, consequently, can adopt the mode of pasting the insulating film at the one side of circuit board and metal sheet contact, improves insulating nature between the two. However, due to the requirement of the accuracy of the magnetic encoder, the flatness of the adhesive film is extremely high, and the operability is poor in practical situations. On the basis of the conception, the multilayer printed circuit board is provided, on one hand, the insulativity between the metal plate and the circuit board can be ensured, and on the other hand, the stability of the magnetic encoder can be ensured.

Fig. 1 is a schematic view of an assembly of a multilayer printed circuit board according to a first embodiment of the present application, including a metal plate 1, a multilayer printed circuit board 2, a magnetic encoder 3, and a motor encoder ring 4, in general, the magnetic encoder 3 is disposed on the multilayer printed circuit board 2, the multilayer printed circuit board 2 is disposed on the metal plate 1, and the multilayer printed circuit board 2 and the metal plate 1 need to be tightly attached to each other, so as to ensure stability of operation of the entire system. One side of the multilayer printed circuit board 2 needs to be connected with the magnetic encoder 3, and the other side needs to be tightly combined with the metal plate 1, but the short circuit problem can not be generated, so the specific structure of the multilayer printed circuit board 2 provided by the application is shown in fig. 2 and 3.

Fig. 2 is a schematic diagram of a structure of a multilayer printed circuit board according to a first embodiment of the present invention, in which the multilayer printed circuit board 2 includes a first core board 21, a second core board 22, and an intermediate layer 25, the intermediate layer 25 is disposed between the first core board 21 and the second core board 22, and the intermediate layer 25 includes an insulating board. In the first embodiment, the intermediate layer 25 includes three insulating plates formed on top of each other, which increases the height of the multilayer printed circuit board 2 by providing different numbers of intermediate layers 25 according to actual installation requirements, but it is not meant that the number of intermediate layers 25 is limited to the number shown in fig. 2. Meanwhile, the middle layer 25 can be an insulating plate, but if a non-insulating plate is matched according to actual needs, the application also allows, and a designer can select a proper combination according to actual needs.

The first core plate 21 includes a first plate surface 211 and a second plate surface 212, optionally, the first core plate 21 is a core plate, the first plate surface 211 and the second plate surface 212 respectively form front and back surfaces of the first core plate 21, the first plate surface 211 and the second plate surface 212 are obtained by processing (for example, etching) the two surfaces of the first core plate 21, and the first plate surface 211 and the second plate surface 212 are communicated with each other through the first guide hole 23. The first plate surface 211 and the second plate surface 212 are provided with lead layers (not shown) for communicating with the magnetic encoder 3. Specifically, the magnetic encoder 3 is disposed on the first board 211, the first board 211 is used for placing components and wires, the second board 212 is also used for wires, and meanwhile, a partial area of the second board 212 can be used as a reference plane for differential signals of the first board 211. It should be noted that the first via 23 may include a plurality of vias, which are respectively connected to the traces on the first board 211 and the second board 212.

The second core board 22 shown in the first embodiment includes a third board surface 221 and a fourth board surface 222, and similar to the first core board 21, optionally, the second core board 22 is a core board, the third board surface 221 and the fourth board surface 222 form the front and back surfaces of the second core board 22, and the third board surface 221 and the fourth board surface 222 are obtained by processing (e.g., etching) the two surfaces of the second core board 22, but no trace or via is provided on the place where the second core board 22 is combined with the metal plate 1, so that a short circuit situation is not generated after the second core board 22 is combined with the metal plate 1. Referring to fig. 2, the multilayer printed circuit board 2 provided by the present application sequentially includes, from top to bottom, a first core board 21, an insulating interlayer 25, and a second core board 22, where the layers are arranged in parallel, and optionally, the rest of the second core board 22 except the position where the second core board is communicated with the first core board 21 is a flat copper surface, so that the flatness of the joint surface can be ensured after the multilayer printed circuit board 2 is combined with the metal plate 1.

Further, the second core 22 is provided with a ground terminal (not shown) and/or a connector port (not shown), and the ground terminal may be provided at a corresponding position of the third board surface 221 and the fourth board surface 222, for example, at the same vertical position shown in fig. 2. A connector port is disposed on the fourth panel 222 for mounting an external component, such as a connector. Except for the connector and the necessary small amount of wires, the rest of the second core board 22 is a large flat grounding copper sheet, and the third board surface 221 and the fourth board surface 222 are only subjected to single-point grounding treatment at the GND pins of the connector, so that the third board surface 221 and the fourth board surface 222 have a good shielding effect on signals of the second board surface 212.

The connector can communicate with an external device, so that the multilayer printed circuit board 2 can transmit signals to the external device. The first core plate 21 and the second core plate 22 communicate with each other through the second guide hole 24, specifically, the first plate surface 211 of the first core plate 21 and the fourth plate surface 222 of the second core plate 22 communicate with each other through the second guide hole 24, and the connector port is provided at a position corresponding to the second guide hole 24. The second via 24 may include a plurality of second vias 24, and the second core board 22 and the first core board 21 are electrically connected through the second vias 24, for example, components on the second core board 22 and components on the first core board 21 are communicated, but it should be noted that the position of the second via 24 disposed on the second core board 22 should be avoided from the position where the second core board 22 is attached to the metal plate 1, that is, the position of the second core board 22 except for the position of the second via 24 is a flat copper surface, so as not to affect the bonding with the metal plate 1. Further, in the process of manufacturing the multilayer printed circuit board 2, the hollow portions of the first via 23 and the second via 24 need to be subjected to a hole plugging process, and optionally, the multilayer printed circuit board 2 provided in the present application, the first via 23 and the second via 24 thereon are filled with a resin filler. In addition, solder resist is applied on the top and

bottom layers

21, 22, each layer having a thickness between 15um-30um, optionally 20um, with a tolerance between 5um-10 um. At this time, after the metal plate 1, the multilayer printed circuit board 2 and the magnetic encoder 3 are mounted, the position accuracy of the magnetic encoder 3 in three dimensional directions can be guaranteed to be +/-0.03 mm.

It should be noted that the second core board 22 may also be configured as a one-board structure, that is, only one of the third board 221 and the fourth board 222 is included, and other components, such as a connector, a ground terminal, and the like, are directly connected to the second core board 22. Those skilled in the art can select a suitable product configuration according to practical needs and cost considerations.

Fig. 3 is a schematic structural diagram of a multilayer printed circuit board according to a second embodiment of the present disclosure, where the second embodiment is the same as the first embodiment in terms of the principle of the scheme and the design of the wiring, but the second embodiment is adjusted in the laminated structure of the multilayer printed circuit board 2, and the multilayer printed circuit board 2 according to the second embodiment is easier to process while meeting the performance requirements of the product. Specifically, the multilayer printed circuit board 2 includes a first board surface 261, a second board surface 262, a third board surface 271, and a fourth board surface 272 that are sequentially stacked, where the second board surface 262 and the third board surface 271 constitute an intermediate core board, a first spacer 281 is disposed between the first board surface 261 and the second board surface 262, a second spacer 282 is disposed between the third board surface 271 and the fourth board surface 272, the first spacer 281 and the second spacer 282 are insulating boards, and optionally, the first spacer 281 and the second spacer 282 are semi-curing boards. In the second embodiment, the first spacer 281 includes two insulating plates which are formed on top of each other, and this is to increase the thickness of the multi-layer pcb 2 by providing different numbers of insulating plates according to actual installation requirements, but it is not meant that the first spacer 281 is limited to the number shown in fig. 3. The first plate surface 261 and the second plate surface 262 are communicated through the first guide hole 23, and the first plate surface 261 and the second plate surface 262 are provided with a conductor layer for communicating with the magnetic encoder 3. Meanwhile, the first plate surface 261 and the fourth plate surface 272 communicate with each other through the second guide hole 24. The second partition 282 is similar to the first partition 281 in structure and will not be described in detail. It should be noted that the second embodiment is different from the first embodiment only in the overlapping manner, but the description in the first embodiment can still be referred to in other structures, and therefore, the description is not repeated.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A multilayer printed circuit board is characterized by comprising a first board surface, a second board surface, a third board surface and a fourth board surface which are arranged in sequence, wherein,

the first board surface and the second board surface are respectively provided with a wire layer, and the first board surface is communicated with the second board surface through a first guide hole;

the fourth board surface is communicated with the first board surface through a second guide hole, and the third board surface and the fourth board surface are flat copper surfaces except the position corresponding to the second guide hole.

2. The multilayer printed circuit board according to claim 1, further comprising an insulating interlayer, the first board face and the second board face constituting a first core board, the third board face and the fourth board face constituting a second core board;

the first core board, the insulating interlayer and the second core board are sequentially stacked.

3. The multilayer printed circuit board according to claim 1, further comprising a first partition plate and a second partition plate, the second plate surface and the third plate surface constituting an intermediate core plate;

the first plate surface, the first partition plate, the middle core plate, the second partition plate and the fourth plate surface are sequentially stacked.

4. The multilayer printed circuit board according to claim 3, wherein the first and second separators comprise a prepreg.

5. The multilayer printed circuit board of claim 1, wherein the fourth board surface is provided with a connector port for connecting an external device.

6. The multilayer printed circuit board of claim 5, wherein the connector port is disposed at a location corresponding to the second via.

7. The multilayer printed circuit board according to claim 5, wherein a ground terminal is provided on the third board surface and the fourth board surface.

8. The multilayer printed circuit board of claim 7, wherein the ground terminals are provided at corresponding positions of the third board surface and the fourth board surface.

9. The multilayer printed circuit board according to claim 1, wherein a resin filler is included in the first via hole and/or the second via hole.

10. The multilayer printed circuit board according to claim 1, further comprising a solder resist, the solder resist being provided on the first board surface and/or the fourth board surface, the solder resist having a thickness of between 15um-30 um.