Printed circuit board, communications device, and manufacturing method

A printed circuit board includes a connector insertion area including many rows of crimping holes, each row of crimping holes includes at least two pairs of signal crimping holes (SCHs), and each pair of SCHs includes two SCHs. In a row arrangement direction of the crimping holes, at least one ground crimping hole (GCH) is arranged on either side of each pair of SCHs. A depth of the GCH is greater than or equal to a depth of the SCH, the GCH includes a main hole and a shielding component on at least one side of the main hole, a part of a side wall of the main hole is a part of a side wall of the shielding component, and a sum of lengths of the main hole and the shielding component in a first direction is greater than a length of the SCHs in the first direction.

TECHNICAL FIELD

Embodiments of this application relate to the field of circuit board technologies, and in particular, to a printed circuit board and a communications device.

BACKGROUND

A printed circuit board (PCB) is an important electronic component in an electronic device, and is a carrier for electrical connections between electronic parts and components. For example, a plurality of printed circuit boards connected to each other generally need to be disposed in a communications device. In a common manner of connecting a plurality of printed circuit boards, as shown inFIG.1, one printed circuit board is used as a backplane10, and the remaining printed circuit boards each are used as a daughter board30. The backplane10and the daughter board30are connected through a connector20.

Either of the backplane10and the daughter board30is provided with signal crimping holes and ground crimping holes that are connected to the connector20. Signal crimping pins in the connector20are inserted into the signal crimping holes, and ground crimping pins are inserted into the ground crimping holes. The backplane10and the daughter board30may be connected through the connector20. A manner of arranging the signal crimping holes and the ground crimping holes on the backplane10or the daughter board30is shown inFIG.2. Ground crimping holes50are on two sides of each pair of signal crimping holes40. When a signal is transmitted between the backplane10and the daughter board30through the connector20, an electromagnetic field between two adjacent pairs of signal crimping holes40is shielded by the ground crimping holes50, to reduce signal crosstalk between the two adjacent pairs of signal crimping holes40.

However, as a signal channel rate and density of the communications device continuously increase, the two adjacent pairs of signal crimping holes40keep approaching. Consequently, it is difficult to achieve an ideal electromagnetic shielding effect by using the foregoing ground crimping holes50, and severe signal crosstalk still exists between the two adjacent pairs of signal crimping holes40.

SUMMARY

Embodiments of this application provide a printed circuit board and a communications device, to reduce signal crosstalk between two adjacent pairs of signal crimping holes.

A first aspect of embodiments of this application provides a printed circuit board, including a connector insertion area. A plurality of rows of crimping holes are arranged in the connector insertion area, each row of crimping holes includes at least two pairs of signal crimping holes arranged at intervals, and each pair of signal crimping holes includes two signal crimping holes. In a row arrangement direction of the crimping holes, at least one ground crimping hole is arranged on either side of each pair of signal crimping holes. A depth of the ground crimping hole is greater than or equal to a depth of the signal crimping hole, the ground crimping hole includes a main hole and a shielding component on at least one side of the main hole, a part of a side wall of the main hole is a part of a side wall of the shielding component, a sum of lengths of the main hole and the shielding component in a first direction is greater than a length of the signal crimping hole in the first direction, and the first direction is a direction that is in a same plane as the row arrangement direction of the crimping holes and that is perpendicular to the row arrangement direction of the crimping holes.

In the printed circuit board provided in the first aspect of embodiments of this application, the ground crimping hole is arranged on either side of each pair of signal crimping holes, the ground crimping hole includes the main hole and the shielding component, and the part of the side wall of the main hole is the part of the side wall of the shielding component, so that an effective shielding area of the ground crimping hole includes at least the main hole and the shielding component, and the sum of the lengths of the main hole and the shielding component in the first direction is greater than the length of the signal crimping hole in the first direction. This significantly increases an effective shielding range of the ground crimping hole, compared with a related design in which a ground crimping hole includes only one main hole. Therefore, when signal crimping pins of a connector are inserted into two adjacent pairs of signal crimping holes and there is a signal, an electromagnetic field between the two adjacent pairs of signal crimping holes can be shielded by the ground crimping hole, and a shape of the electromagnetic field and line distribution of the electromagnetic field can also be changed, so that signal crosstalk between the two adjacent pairs of signal crimping holes can be reduced.

In a possible implementation, a first metal plating layer is disposed on an internal surface of the main hole. This design can enable conducting layers in the printed circuit board to be electrically connected, to improve a ground effect, and can further enhance a shielding effect by using the first metal plating layer and the shielding component that are in contact.

In a possible implementation, the shielding component includes an auxiliary hole arranged in the printed circuit board, the part of the side wall of the main hole is a first part of a side wall of the auxiliary hole, and a second metal plating layer is disposed on an internal surface of a part of the side wall of the auxiliary hole other than the first part of the side wall of the auxiliary hole.

This design can further improve a shielding effect and reduce signal crosstalk between two adjacent pairs of signal crimping holes by using the second metal plating layer.

In a possible implementation, the auxiliary hole is filled with resin or green oil. This design can ensure that a surface of the printed circuit board keeps flat, and can also enhance strength of the side wall of the auxiliary hole and improve durability of the ground crimping hole by using the resin or green oil filled into the auxiliary hole.

In a possible implementation, the auxiliary hole is a crescent-shaped hole, a circular hole, an elliptical hole, a strip-shaped hole, or a runway-shaped hole.

In a possible implementation, the shielding component includes a plurality of first metal layers and a plurality of second metal layers that are alternately stacked. The first metal layer is an area of each conducting layer that is located in the connector insertion area in the printed circuit board, and the second metal layer is formed by an area of each dielectric layer in the connector insertion area in the printed circuit board through a displacement reaction. The area of each conducting layer corresponds to the area of each dielectric layer in a thickness direction of the printed circuit board.

According to the foregoing design, the shielding component includes a part of the printed circuit board, in other words, the shielding component and the printed circuit board are in an integrated structure, so that overall strength of the printed circuit board can be ensured.

In a possible implementation, the ground crimping hole includes two shielding components, and the two shielding components are on two sides of the main hole in the first direction.

In a possible implementation, the ground crimping hole includes at least three shielding components, and the at least three shielding components are arranged at equal intervals around the main hole.

In a possible implementation, a main hole plate is disposed on the periphery of the main hole, and an auxiliary hole plate is disposed on the periphery of the shielding component. This design can increase a ground area of the printed circuit board and improve a ground effect of the printed circuit board by using the main hole plate and the auxiliary hole plate.

In a possible implementation, in two adjacent rows of crimping holes, in the first direction, any pair of signal crimping holes in a current row and any pair of signal crimping holes in a next row are staggered, and a ground crimping hole in the current row and a ground crimping hole in the next row are staggered.

The foregoing design can increase a distance between two adjacent up-down rows of signal crimping holes, to reduce signal crosstalk between two adjacent up-down pairs of signal crimping holes in the two adjacent rows, and can further change a shape and distribution of an electromagnetic field between the two adjacent up-down pairs of signal crimping holes in the two adjacent rows, to reduce signal crosstalk between the two adjacent up-down pairs of signal crimping holes in the two adjacent rows.

A second aspect of embodiments of this application provides another printed circuit board, including a connector insertion area. A plurality of rows of crimping holes are arranged in the connector insertion area, each row of crimping holes includes at least two pairs of signal crimping holes arranged at intervals, and each pair of signal crimping holes includes two signal crimping holes. In a row arrangement direction of the crimping holes, at least one ground crimping hole is arranged on either side of each pair of signal crimping holes. A depth of the ground crimping hole is greater than or equal to a depth of the signal crimping hole, the ground crimping hole includes a main part and an auxiliary part connected to the main part, a third metal plating layer is disposed on an internal surface of the auxiliary part, a sum of lengths of the main part and the auxiliary part in a first direction is greater than a length of the signal crimping hole in the first direction, and the first direction is a direction that is in a same plane as the row arrangement direction of the crimping holes and that is perpendicular to the row arrangement direction of the crimping holes.

In the printed circuit board provided in the second aspect of embodiments of this application, the ground crimping hole is arranged on either side of each pair of signal crimping holes, the ground crimping hole includes the main part and the auxiliary part connected to the main part, and the third metal plating layer is disposed on the internal surface of the auxiliary part, so that an effective shielding area of the ground crimping hole includes at least the main part and the third metal plating layer, and the sum of the lengths of the main part and the auxiliary part in the first direction is greater than the length of the signal crimping hole in the first direction. This significantly increases an effective shielding range of the ground crimping hole, compared with a related design in which a ground crimping hole includes only one main hole. Therefore, when signal crimping pins of a connector are inserted into two adjacent pairs of signal crimping holes and there is a signal, an electromagnetic field between the two adjacent pairs of signal crimping holes can be shielded by the foregoing ground crimping hole, and a shape of the electromagnetic field and line distribution of the electromagnetic field can also be changed, so that signal crosstalk between the two adjacent pairs of signal crimping holes can be reduced.

In a possible implementation, a fourth metal plating layer is disposed on an internal surface of the main part, and the fourth metal plating layer is connected to the third metal plating layer. This design can improve an effect of shielding a signal between the two adjacent pairs of signal crimping holes by the main part, and can further improve a ground effect by connecting conducting layers in the printed circuit board.

In a possible implementation, a cross section of the ground crimping hole is peanut-shaped or dumbbell-shaped by using a surface parallel to the printed circuit board as a cross section.

In a possible implementation, a hole plate is disposed on the periphery of the ground crimping hole. This design can increase a ground area of the printed circuit board and improve a ground effect of the printed circuit board by using the hole plate disposed on the periphery of the ground crimping hole.

A third aspect of embodiments of this application provides a communications device, including the printed circuit board provided in the foregoing embodiments and a connector that fits with the printed circuit board. A signal crimping pin in the connector is inserted into a signal crimping hole of the printed circuit board, and a ground crimping pin in the connector is inserted into a ground crimping hole.

The communications device includes the printed circuit board according to the first aspect and the second aspect. Therefore, the communications device also has advantages of the printed circuit board. Details are not described herein again.

DESCRIPTION OF REFERENCE NUMERALS

DESCRIPTION OF EMBODIMENTS

To make the foregoing objectives, features, and advantages of embodiments of this application clearer, the following clearly and describes the technical solutions of embodiments of this application with reference to the accompanying drawings in embodiments of this application. It is clear that the described embodiments are merely some but not all the embodiments of this application. All other embodiments obtained by persons of ordinary skill in the art according to embodiments of this application without creative efforts shall fall within the protection scope of this application.

A printed circuit board provided in embodiments of this application may be a single-layer board, or may be a multi-layer board. For example, as shown inFIG.3, a printed circuit board1is a multi-layer board, and includes a plurality of conducting layers11and a plurality of dielectric layers12, and the plurality of conducting layers11and the plurality of dielectric layers12are alternately stacked. The conducting layer11is generally made of copper foil, and is used to form a line in the printed circuit board. The dielectric layer12is generally made of resin, glass fiber, or the like, and is used to electrically isolate two adjacent conducting layers11.

To implement a connection between printed circuit boards, as shown inFIG.4, a connector insertion area2is generally disposed on the printed circuit board1, and a location of the connector insertion area2in the printed circuit board1is not limited. For example, the connector insertion area2may be in a four-corner area of the printed circuit board1, or may be in a center area. A plurality of rows of crimping holes are arranged in the connector insertion area2, each row of crimping holes includes at least two pairs of signal crimping holes40arranged at intervals, and each pair of signal crimping holes40includes two signal crimping holes40. For example, in an embodiment shown inFIG.4, three rows of crimping holes are arranged in the connector insertion area2, each row of crimping holes includes two pairs of signal crimping holes40, and each pair of signal crimping holes may be used to transmit a differential signal.

In a same row of crimping holes, at least one ground crimping hole50is arranged on either side of each pair of signal crimping holes40. Alternatively, in a same row of crimping holes, a ground crimping hole50is arranged between any two adjacent pairs of signal crimping holes40, so that the two adjacent pairs of signal crimping holes40are separated by the ground crimping hole50. The ground crimping hole50matches a ground crimping pin of a connector, so that the ground crimping pin in the connector is inserted into the ground crimping hole50. In addition, an electromagnetic field between the two pairs of signal crimping holes40on two sides of the ground crimping hole50may be shielded by the ground crimping hole50, to reduce signal crosstalk between the two adjacent pairs of signal crimping holes40.

It should be noted that the signal crimping hole40may penetrate the printed circuit board1in a thickness direction of the printed circuit board1, in other words, the signal crimping hole40is a through-hole, and a depth of the signal crimping hole40is the same as a thickness of the printed circuit board1. However, no limitation is imposed thereto. Alternatively, the signal crimping hole40may not penetrate the printed circuit board1in a thickness direction of the printed circuit board1, in other words, the signal crimping hole40is a blind hole, and a depth of the signal crimping hole40is less than a thickness of the printed circuit board1. Similarly, the ground crimping hole50may penetrate the printed circuit board1in the thickness direction of the printed circuit board1, or may not penetrate the printed circuit board1, and it only needs to ensure that a depth of the ground crimping hole50is greater than or equal to the depth of the signal crimping hole40, to shield the electromagnetic field between the two adjacent pairs of signal crimping holes40. For example, as shown inFIG.5, in the thickness direction of the printed circuit board1, both the signal crimping hole40and the ground crimping hole50penetrate the printed circuit board1, in other words, both the depth of the ground crimping hole50and the depth of the signal crimping hole40are equal to the thickness of the printed circuit board1.

To reduce the signal crosstalk between the two adjacent pairs of signal crimping holes40, there are a plurality of forms of ground crimping holes50. The following provides descriptions by using an example with reference to the accompanying drawings of this specification.

FIG.6is a diagram of arranging signal crimping holes and ground crimping holes in a connector insertion area according to Embodiment 1 of this application.FIG.7is a section view of a ground crimping hole inFIG.6. In this embodiment, a plurality of rows of crimping holes are arranged in the connector insertion area2, each row of crimping holes includes at least two pairs of signal crimping holes40arranged at intervals, and each pair of signal crimping holes40includes two signal crimping holes. In a same row of crimping holes, at least one ground crimping hole50is arranged on either side of each pair of signal crimping holes40. The ground crimping hole50includes a main hole51and at least one shielding component, a part of a side wall of the main hole51is a part of a side wall of the shielding component50a, a sum of lengths of the main hole51and the shielding component50ain a first direction is greater than a length of the signal crimping hole40in the first direction, and the first direction is a direction that is in a same plane as a row arrangement direction of the crimping holes and that is perpendicular to the row arrangement direction of the crimping holes. For example, in the embodiment shown inFIG.6, the row arrangement direction of the crimping holes is a transverse direction inFIG.6, and the first direction B is a longitudinal direction inFIG.6. In addition, the first direction B and the row arrangement direction of the crimping holes are in the same plane.

In this embodiment, the main hole51may penetrate the printed circuit board1in the thickness direction of the printed circuit board1, or may not penetrate the printed circuit board1, and it only needs to ensure that a depth of the main hole51is greater than or equal to the depth of the signal crimping hole40. A shape of the main hole51is the same as or similar to a shape of a ground crimping pin in a connector. For example, the shape of the ground crimping pin is generally circular, elliptical, or oblate. Correspondingly, the main hole51may be a circular hole, an elliptical hole, or an oblate hole. In this embodiment, the main hole51is a circular hole. A design of a circular main hole implements simple manufacturing, low costs, and high precision of limiting a location of the ground crimping pin. The main hole51is used to fit with the ground crimping pin in the connector. In addition, when the ground crimping pin in the connector is inserted into the main hole51, a part of a side surface of the ground crimping pin is in close contact with a part of a side surface of the shielding part50a, so that there is no gap between the ground crimping pin and the shielding part, to prevent a signal between the main hole51and the shielding component50a.

In a possible implementation, as shown inFIG.7, a first metal plating layer52is disposed on an internal surface of the main hole51, and the first metal plating layer52may be formed through electroplating, evaporation deposition, sputtering, chemical plating, or vapor deposition. In this embodiment, the first metal plating layer is formed through electroplating. The first metal plating layer52may be made of a metal material such as copper, aluminum, or silver or another alloy material. In this embodiment, the first metal plating layer52is a copper plating layer. The first metal plating layer52is disposed on the internal surface of the main hole51, so that all conducting layers in the printed circuit board1can be electrically connected. After the ground crimping pin in the connector is inserted into the main hole51, the side surface of the ground crimping pin may be simultaneously in contact with all the conducting layers, to improve a ground effect. In addition, an area that is of the first metal plating layer52and that corresponds to the shielding component50ais attached to the shielding component50a, so that there is no gap between the first metal plating layer52and the shielding component50a, to prevent a signal between the first metal plating layer52and the shielding component50a.

The shielding component50ais on the periphery of the main hole51, and may be on one side, two sides, or around the main hole51, or the shielding component50ais disposed on one side, two sides, or around the main hole51. For example, in the embodiment shown inFIG.7, one shielding component50ais disposed on either of upper and lower sides of the main hole51in the first direction. The shielding component50aincludes but is not limited to the following several possible structure forms.

In a possible structure form, as shown inFIG.7, the shielding component50aincludes two auxiliary holes54on the upper and lower sides of the main hole51. The two auxiliary holes54may be through-holes penetrating the printed circuit board1, or may be blind holes penetrating a part of the thickness of the printed circuit board1. A part of a side wall of the auxiliary hole54overlaps a part of the side wall of the main hole51between the auxiliary hole54and the main hole51, or the auxiliary hole54and the main hole51share a part of a side wall between the auxiliary hole54and the main hole51, or a part of the side wall of the main hole51is a first part54aof a side wall of the auxiliary hole54, so that there is no gap between the main hole51and the auxiliary hole54, to prevent a signal between the main hole51and the auxiliary hole54.

A second metal plating layer55is disposed on an internal surface of the auxiliary hole54. The second metal plating layer55is on the internal surface of the auxiliary hole54other than the first part54a, in other words, the second metal plating layer55is a semi-closed structure having an opening on a side facing the main hole51. Two ends of the opening of the second metal plating layer55are separately in contact with the first metal plating layer52, so that the second metal plating layer55and a part of the first metal plating layer52at the two ends of the opening of the second metal plating layer55form a closed ring. In other words, the main hole51is a complete hole, and the auxiliary hole54is a non-complete hole. In this specification, a side wall of the main hole51that is a complete hole can form a closed ring, and a side wall of the auxiliary hole54that is a non-complete hole cannot form a closed ring and has a gap or an opening. For example, as shown inFIG.7, a closed circular hole is formed by the side wall of the main hole51, a semi-closed crescent-shaped hole is formed by the side wall of the auxiliary hole54, and a side that is of the auxiliary hole54and that faces the main hole51has an opening. In this way, there is no gap between the first metal plating layer52and the second metal plating layer55, to prevent a signal between the first metal plating layer52and the second metal plating layer55, and reduce signal crosstalk between two adjacent pairs of signal crimping holes40.

The auxiliary hole54may be a crescent-shaped hole, a circular hole, an elliptical hole, a strip-shaped hole, or a runway-shaped hole. In the embodiment shown inFIG.7, the auxiliary hole54is a crescent-shaped hole. In a possible implementation, the auxiliary hole54is filled with resin or green oil. This design can ensure that a surface of the printed circuit board1keeps flat, and can also enhance strength of the side wall of the auxiliary hole54and improve durability of the ground crimping hole50by using the resin or green oil filled into the auxiliary hole54.

A main hole plate53is disposed on the periphery of the main hole51, and an auxiliary hole plate56is disposed on the periphery of the auxiliary hole54. The main hole plate53and the auxiliary hole plate56may be of an integrated structure. Similar to a soldering pad in the printed circuit board1, the main hole plate53is a conducting area around the main hole51, and an area of the main hole plate53is greater than a cross-sectional area of the main hole51, so that a ground area of the main hole51can be increased. Likewise, similar to a soldering pad in the printed circuit board1, the auxiliary hole plate56is a conducting area around the auxiliary hole54, and an area of the auxiliary hole plate56is greater than a cross-sectional area of the auxiliary hole54, so that a ground area of the auxiliary hole54can be increased. The main hole plate53and the auxiliary hole plate56are respectively disposed around the main hole51and the auxiliary hole54, to increase the ground area of the main hole51and the ground area of the auxiliary hole54, and improve a ground effect of the ground crimping hole50.

It may be understood that a form of the ground crimping hole50is not limited to the structure form described in the foregoing embodiment, and another structure form may be used. For example, as shown inFIG.8andFIG.9, the ground crimping hole50includes the main hole51and the auxiliary hole54on either side of the main hole51. The main hole51is a circular hole. The part of the side wall of the main hole51is formed by the part of the side wall of the auxiliary hole54, in other words, the part of the side wall of the main hole51is the part of the side wall of the auxiliary hole54. The first metal plating layer52is disposed on the internal surface of the main hole51, the auxiliary hole54is a runway-shaped hole, the second metal plating layer55is disposed on the internal surface of the auxiliary hole54, and the auxiliary hole54is filled with resin or green oil, to ensure that the surface of the printed circuit board1keeps flat, and can also enhance strength of the side wall of the auxiliary hole54and improve durability of the ground crimping hole50.

In addition, the auxiliary hole54is not limited to being distributed on either side of the main hole51. Alternatively, the auxiliary hole54may be distributed on one side of the main hole51or around the main hole51. For example, as shown inFIG.10, a quantity of auxiliary holes54is greater than or equal to 3. These auxiliary holes54are arranged around the main hole51at equal intervals.

In another possible structure form, the shielding component50aincludes a plurality of first metal layers and a plurality of second metal layers that are alternately stacked. The first metal layer is an area of each conducting layer11that is located in the connector insertion area2in the printed circuit board1, and the second metal layer is formed by an area of each dielectric layer12in the connector insertion area2in the printed circuit board1through a displacement reaction. The area of each conducting layer11corresponds to the area of each dielectric layer12in a thickness direction of the printed circuit board1. The shielding component50amay be manufactured in the following manner.

Before the shielding component50aalternately laminates the conducting layers11and the dielectric layers12to form the printed circuit board1, metal oxidation replacement processing may be performed on some dielectric layers12in the connector insertion area2, so that some dielectric layers12in the connector insertion area2are of a conducting structure, in other words, the second metal layers are formed. Then, the dielectric layers12and the conducting layers11having the second metal layers are alternately stacked to form the printed circuit board1.

Embodiment 2 of this application provides a printed circuit board1. As shown inFIG.11andFIG.12, the printed circuit board1also includes a connector insertion area2. A plurality of rows of crimping holes are arranged in the connector insertion area2, each row of crimping holes includes at least two pairs of signal crimping holes40arranged at intervals, and each pair of signal crimping holes40includes two signal crimping holes40. In a row arrangement direction of the crimping holes, at least one ground crimping hole50is arranged on either side of each pair of signal crimping holes40. A depth of the ground crimping hole50is greater than or equal to a depth of the signal crimping hole40.

A difference between Embodiment 2 and Embodiment 1 is as follows. The ground crimping hole50includes a main body61and an auxiliary part64connected to the main body61, a third metal plating layer65is disposed on an internal surface of the auxiliary part64, a sum of lengths of the main part61and the auxiliary part64in a first direction B is greater than a length of the signal crimping hole40in the first direction, and the first direction B is a direction that is in a same plane as the row arrangement direction of the crimping holes and that is perpendicular to the row arrangement direction of the crimping holes.

In this embodiment, the ground crimping hole50includes two parts: the main body61and the auxiliary part64. A side wall of the main body61is connected to a side wall of the auxiliary part64, so that the ground crimping hole50is jointly formed by the side wall of the main body61and the side wall of the auxiliary part64. For example, as shown inFIG.12, the main body61includes two first side walls61a, and the two first side walls61aare disposed oppositely, to fit with a ground crimping pin in the connector and limit a location of the ground crimping pin. The auxiliary part64includes one second side wall64a. A semi-circular structure is formed by the second side wall64a. Two ends of the second side wall64aare respectively connected to ends of the two first side walls61a. The two second side walls64aon two sides of the main body61and the two first side walls61aof the main body61jointly form a long-strip-shaped hole. A length of the long-strip-shaped hole in the first direction B is greater than the length of the signal crimping hole40in the first direction.

A third metal plating layer65is disposed on an internal surface of the second side wall64a, in other words, on the internal surface of the auxiliary part64, and the third metal plating layer65may be formed through electroplating, evaporation deposition, sputtering, chemical plating, or vapor deposition. In this embodiment, the third metal plating layer is formed through electroplating. The third metal plating layer65may be made of a metal material such as copper, aluminum, or silver or another alloy material. In this embodiment, the third metal plating layer65is a copper plating layer. When the ground crimping pin in the connector is inserted into the main body61, a part of a side surface of the ground crimping pin may be in contact with the third metal plating layer65, and the ground crimping pin and the third metal plating layer65jointly form a barrier for isolating an electromagnetic field on two sides of the ground crimping hole50, to reduce signal crosstalk between two adjacent pairs of signal crimping holes40

In the printed circuit board provided in Embodiment 2 of this application, the ground crimping hole50is arranged on either side of each pair of signal crimping holes40, the ground crimping hole50includes the main part61and the auxiliary part64connected to the main part61, and the third metal plating layer65is disposed on the internal surface of the auxiliary part64, so that an effective shielding area of the ground crimping hole50includes at least the main part61and the third metal plating layer65, and the sum of the lengths of the main part61and the auxiliary part64in the first direction is greater than the length of the signal crimping hole40in the first direction. This significantly increases an effective shielding range of the ground crimping hole50, compared with a related design in which a ground crimping hole includes only one main hole. Therefore, when the signal crimping pins of the connector are inserted into two adjacent pairs of signal crimping holes40and there is a signal, an electromagnetic field between the two adjacent pairs of signal crimping holes40can be shielded by the foregoing ground crimping hole50, and a shape of the electromagnetic field and line distribution of the electromagnetic field between the two adjacent pairs of signal crimping holes40can also be changed, so that signal crosstalk between the two adjacent pairs of signal crimping holes40can be reduced.

In the foregoing embodiment, disposing the third metal plating layer65on the internal surface of the auxiliary part64may not only improve an effect of shielding the electromagnetic field between the two adjacent pairs of signal crimping holes40, but also improve a ground effect of each conducting layer in the printed circuit board1.

A metal plating layer may be disposed on an internal surface of the main body61, or no metal plating layer may be disposed. In an optional implementation, a fourth metal plating layer62is disposed on the internal surface of the main body61, in other words, on an internal surface of the first side wall61a, and the fourth metal plating layer62is connected to the third metal plating layer65. The fourth metal plating layer62may be formed through electroplating, evaporation deposition, sputtering, chemical plating, or vapor deposition. In this embodiment, the fourth metal plating layer is formed through electroplating. The fourth metal plating layer62may be made of a metal material such as copper, aluminum, or silver or another alloy material. In this embodiment, the fourth metal plating layer62is a copper plating layer.

In the embodiment shown inFIG.12, a cross section of the ground crimping hole50is peanut-shaped by using a surface parallel to the printed circuit board1as a cross section. However, no limitation is imposed thereto. As shown inFIG.13andFIG.14, the cross section of the ground crimping hole50may alternatively be dumbbell-shaped.

A main body hole plate63is disposed on the periphery of the main body61, and an auxiliary part hole plate66is disposed on the periphery of the auxiliary part64. The main body hole plate63and the auxiliary part hole plate66may be of an integrated structure, in other words, a hole plate is disposed on the periphery of the ground crimping hole50. Similar to a soldering pad in the printed circuit board1, the main part hole plate63is a conducting area around the main part61, and an area of the main part hole plate63is greater than a cross-sectional area of the main part61, so that a ground area of the main part61can be increased. Likewise, similar to a soldering pad in the printed circuit board1, the auxiliary part hole plate66is a conducting area around the auxiliary part64, and an area of the auxiliary part hole plate66is greater than a cross-sectional area of the auxiliary part64, so that a ground area of the auxiliary part64can be increased. The main part hole plate63and the auxiliary part hole plate66are respectively disposed around the main part61and the auxiliary part64, to increase the ground area of the main part61and the ground area of the auxiliary part64, and improve a ground effect of the ground crimping hole50.

In Embodiment 1, when the ground crimping hole50is designed as shown inFIG.7, the ground crimping hole50may be manufactured by using the following preparation method.

Step1: Etch each conducting layer in the connector insertion area2in the printed circuit board to form a main hole plate and an auxiliary hole plate.

Further, before the printed circuit board1is manufactured, each conducting layer that forms the printed circuit board may be etched to form a main hole plate53and an auxiliary hole plate56in an area at each conducting layer that corresponds to the connector insertion area2. The main hole plate53and the auxiliary hole plate56may be formed in one etching process, or may be formed respectively in two etching processes. Then, the conducting layers and dielectric layers having the main hole plate53and the auxiliary hole plate56are alternately laminated to form the printed circuit board1having the main hole plate53and the auxiliary hole plate56.

Step2: Drill the two auxiliary holes54in the printed circuit board having the main hole plate53and the auxiliary hole plate56with a drill bit. For example, the two auxiliary holes54are drilled with a drill bit of 16 mil at a spacing of 24 mil. The auxiliary hole plate56is disposed on the periphery of the auxiliary hole54. Alternatively, drilling is performed in an area of the auxiliary hole plate56with a drill bit, to form the two auxiliary holes54in the auxiliary hole plate56.

Step3: Perform copper plating on an internal surface of the auxiliary hole54, to form the second metal plating layer55, where an annular through-hole is formed by the second metal plating layer55in the auxiliary hole54.

Further, the second metal plating layer55may be formed on the internal surface of the auxiliary hole54through evaporation deposition, sputtering, electroplating, chemical plating, or vapor deposition, and the second metal plating layer55covers the internal surface of the auxiliary hole54.

Step4: Fill the annular through-hole formed by the second metal plating layer55with resin or green oil.

Filling the annular through-hole formed by the second metal plating layer with resin or green oil can ensure that a surface of the printed circuit board keeps flat, and can also help subsequently form a main hole51and form a first metal plating layer52in the main hole51.

Step5: Perform drilling in the center of the two auxiliary holes54to form the main hole51. Further, the main hole51is formed by performing drilling at a symmetrical center of the two auxiliary holes54, for example, by performing drilling with a drill bit of 18 mil. A center of the main hole51is the symmetrical center of the two auxiliary holes54. Side walls on upper and lower sides of the main hole51are formed in the two auxiliary holes54, in other words, the side walls of the upper and lower sides of the main hole51are respectively parts of side walls of the auxiliary holes54on the upper and lower sides of the main hole51.

Step6: Perform copper plating in the main hole51to form the first metal plating layer52. Further, the first metal plating layer52may be formed on the internal surface of the main hole51through evaporation deposition, sputtering, electroplating, chemical plating, or vapor deposition, and the first metal plating layer52covers the internal surface of the main hole51. In addition, a through-hole into which the ground crimping pin of the connector is inserted is formed by the first metal plating layer in the main hole51.

According to the foregoing preparation method, the main hole51and the two auxiliary holes54may be formed through several times (for example, three times) of drilling. In a case in which an area of the connector insertion area2in the printed circuit board1is relatively small, reducing a quantity of times of drilling can reduce process difficulty, and can reduce influence on overall strength of the printed circuit board1, so that the printed circuit board1has better strength.

It may be understood that, in the embodiment shown inFIG.7, the drill bit may be replaced with a milling cutter, and the main hole51and the auxiliary holes54may be machined in the printed circuit board by using the milling cutter. In addition, in the foregoing process of manufacturing the ground crimping hole50, the second metal plating layer may not be formed in the auxiliary hole54first. Instead, film coating may be performed in the main hole51and the auxiliary hole54to obtain the first metal plating layer and the second metal plating layer once after the auxiliary hole54and the main hole51are formed. The structure of the ground crimping hole50shown inFIG.12may be manufactured in this manner.

In Embodiment 1, when the ground crimping hole50is designed as shown inFIG.9, the ground crimping hole50may be manufactured by using the following preparation method.

Step1: Etch each conducting layer in the connector insertion area in the printed circuit board to form a main hole plate and an auxiliary hole plate.

Further, before the printed circuit board1is manufactured, each conducting layer11that forms the printed circuit board1may be etched to form a main hole plate53and an auxiliary hole plate56in an area at each conducting layer11that corresponds to the connector insertion area2. The main hole plate53and the auxiliary hole plate56may be formed in one etching process, or may be formed respectively in two etching processes. Then, the conducting layers11and dielectric layers12having the main hole plate53and the auxiliary hole plate56are alternately laminated to form the printed circuit board1having the main hole plate53and the auxiliary hole plate56.

Step2: Drill the two auxiliary holes in the printed circuit board having the main hole plate and the auxiliary hole plate with a drill bit.

For example, drilling is performed with a drill bit of 12 mil. A specific method may be first drilling a hole with a diameter of 12 mil in the connector insertion area2, and then keeping the drill bit rotated and moving the drill bit in a direction perpendicular to the first direction. The drill bit moves for a distance of, for example, 10 mil. In a process of moving the drill bit, a runway-shaped auxiliary hole54is formed, and then the other auxiliary hole54is formed in the connector insertion area2. A spacing distance between the other auxiliary hole54and the formed auxiliary hole54may be 26 mil. Because structure shapes of the two auxiliary holes54are the same, details are not described again.

Step3: Perform copper plating on an internal surface of the auxiliary hole, to form the second metal plating layer, where an annular through-hole is formed by the second metal plating layer in the auxiliary hole. Further, the second metal plating layer55may be formed on the internal surface of the auxiliary hole54through evaporation deposition, sputtering, electroplating, chemical plating, or vapor deposition, and the second metal plating layer55covers the internal surface of the auxiliary hole54.

Step4: Fill the annular through-hole formed by the second metal plating layer with resin or green oil.

Filling the annular through-hole formed by the first second plating layer55with resin or green oil can ensure that a surface of the printed circuit board keeps flat, and can also help subsequently form a main hole51and form a complete first metal plating layer52in the main hole51.

Step5: Perform drilling in the center of the two auxiliary holes to form the main hole. Further, the main hole51is formed by performing drilling at a symmetrical center of the two auxiliary holes54, for example, by performing drilling with a drill bit of 16 mil. A center of the main hole51is the symmetrical center of the two auxiliary holes54. Side walls on upper and lower sides of the main hole51are formed in the two auxiliary holes54, in other words, the side walls of the upper and lower sides of the main hole51are respectively parts of side walls of the auxiliary holes54on the upper and lower sides of the main hole51.

Step6: Perform copper plating in the main hole51to form the first metal plating layer. Further, the first metal plating layer52may be formed on the internal surface of the main hole51through evaporation deposition, sputtering, electroplating, chemical plating, or vapor deposition, and the first metal plating layer52covers the internal surface of the main hole51. In addition, a through-hole into which the ground crimping pin of the connector is inserted is formed by the first metal plating layer in the main hole51.

It may be understood that, in the embodiment shown inFIG.9, the drill bit may be replaced with a milling cutter, and the main hole51and the auxiliary holes54may be machined in the printed circuit board by using the milling cutter. In this case, side walls between the main hole51and the auxiliary holes54are connected. In addition, in the foregoing process of manufacturing the ground crimping hole50, the second metal plating layer may not be formed in the auxiliary hole54first. Instead, electroplating may be performed in the main hole51and the auxiliary hole54to obtain the first metal plating layer and the second metal plating layer once after the auxiliary hole54and the main hole51are formed. The ground crimping hole50shown inFIG.14may be manufactured in this manner.

It should be noted that, when metal plating layers are formed in the main hole51and the auxiliary hole54, or when metal plating layers are formed in the main part61and the auxiliary part64, an optional metal plating manner is, when the main hole51and the auxiliary hole54or when the main part61and the auxiliary part64are blind holes that do not penetrate the printed circuit board, forming the metal plating layers in the blind holes, and another optional metal plating manner is, when the main hole51and the auxiliary hole54or when the main part61and the auxiliary part64are through-holes that penetrate the printed circuit board, forming the metal plating layers in the through-holes. Forming a metal plating layer in a through-hole generally includes covering the entire internal surface of the through-hole with the metal plating layer and covering the internal surface of the through-hole with the metal plating layer within a specified depth. When the internal surface of the through-hole is covered with the metal plating layer within the specified depth, the entire internal surface of the through-hole is generally covered with the metal plating layer, and then a redundant metal plating layer in the through-hole is removed through backdrilling. For example, the printed circuit board includes15conducting layers, and when the first to the eighth conducting layers need to be connected, a through-hole that penetrates the printed circuit board is usually drilled on the printed circuit board1first, and then metal plating layers are formed on an internal surface of the through-hole. The metal plating layers cover the first to the fifteenth conducting layers in the through-hole, but actually only need to cover the first to the eighth conducting layers in the through-hole, and the metal plating layers at the ninth to the fifteenth conducting layers are not connected by lines. This part of redundant metal plating layers will affect signal integrity and may cause resonance problems. In this case, the part of metal plating layers may be drilled off on the back of the printed circuit board1, in other words, the part of metal plating layers may be removed through backdrilling.

Signal crosstalk between two adjacent pairs of signal crimping holes40generally includes NEXT and FEXT. The NEXT means that, after one pair of signal crimping holes40transmits a signal, the signal is received at a signal input end (near end) of the other pair of signal crimping holes40. This is referred to as the NEXT. The FEXT means that, after one pair of signal crimping holes40transmits a signal, the signal is received at a signal output end (far end) of the other pair of signal crimping holes40. This is referred to as the FEXT. A signal crosstalk reduction effect may be obtained below through simulation analysis by using the foregoing embodiment.

In a conventional design of the ground crimping hole50, the ground crimping hole50between the two adjacent pairs of signal crimping holes40has only one main hole.

When signals in one pair of signal crimping holes40are disturbed signals, signals in other three pairs of signal crimping holes40adjacent to the pair of signal crimping holes40are scrambled signals. For example, as shown inFIG.15, the first pair of signal crimping holes from the left in the third row are disturbed signals and are represented by DIFF1, and for three pairs of signal crimping holes (including two pairs of signal crimping holes in the second row and the second pair of signal crimping holes from the left in the same row (the third row)) adjacent to the first pair of signal crimping holes, NEXT is represented by DIFF3, DIFF5, and DIFF7, and FEXT is represented by DIFF4, DIFF6, and DIFF8respectively. DIFF3and DIFF4, DIFF5and DIFF6, and DIFF7and DIFF8are near ends and far ends of the three pairs of signal crimping holes40respectively.FIG.15shows only near ends DIFF3, DIFF5, and DIFF7due to a limited viewing angle, and does not show far ends DIFF4, DIFF6, and DIFF8(on the other side of the printed circuit board, and obscured by the printed circuit board).

By performing signal crosstalk simulation analysis on the structure shown inFIG.15, NEXT simulation curves of DIFF3, DIFF5, and DIFF7may be separately obtained, as shown inFIG.16, and FEXT simulation curves of DIFF4, DIFF6, and DIFF8may be separately obtained, as shown inFIG.17. According to the NEXT simulation curves shown inFIG.16, it may be learned that NEXT signal strengths are respectively −40.8 decibel (dB)/−47.5 dB/−50.3 dB/@15 gigahertz (GHz). According to the FEXT simulation curves shown inFIG.17, it may be learned that FEXT signal strengths are respectively −33.9 dB/−37.8 dB/−36.0 dB/@15 GHz. For details, refer to Table 1.

When the design solution for the ground crimping hole50shown inFIG.7is used, as shown inFIG.18, similarly, the first pair of signal crimping holes from the left in the third row are disturbed signals and are represented by DIFF1, and for three pairs of signal crimping holes (including two pairs of signal crimping holes in the second row and the second pair of signal crimping holes from the left in the same row (the third row)) adjacent to the first pair of signal crimping holes, NEXT is represented by DIFF3, DIFF5, and DIFF7, and FEXT is represented by DIFF4, DIFF6, and DIFF8respectively. By performing signal crosstalk simulation analysis on the structure shown inFIG.18, NEXT simulation curves of DIFF3, DIFF5, and DIFF7may be separately obtained, as shown inFIG.19, and FEXT simulation curves of DIFF4, DIFF6, and DIFF8may be separately obtained, as shown inFIG.20. According to the NEXT simulation curves shown inFIG.19, it may be learned that NEXT signal strengths are respectively −48.2 dB/−53.3 dB/−59.6 dB/@15 GHz. According to the FEXT simulation curves shown inFIG.20, it may be learned that FEXT signal strengths are respectively −40.2 dB/−45.9 dB/−47.2 dB/@15 GHz. For details, refer to Table 1.

It can be learned from Table 1 that, compared with a conventional solution of designing a ground crimping hole, the solution of designing a ground crimping hole shown inFIG.7can reduce NEXT by about 6 to 9 dB/@15 GHz, and can reduce FEXT by about 6 to 11 dB/@15 GHz. In other words, compared with the conventional solution of designing a ground crimping hole, the solution of designing a ground crimping hole shown inFIG.7significantly reduces signal crosstalk between two adjacent pairs of signal crimping holes40.

When the design solution for the ground crimping hole50shown inFIG.9is used, as shown inFIG.21, similarly, the first pair of signal crimping holes from the left in the third row are disturbed signals and are represented by DIFF1, and for three pairs of signal crimping holes (including two pairs of signal crimping holes in the second row and the second pair of signal crimping holes from the left in the same row (the third row)) adjacent to the first pair of signal crimping holes, NEXT is represented by DIFF3, DIFF5, and DIFF7, and FEXT is represented by DIFF4, DIFF6, and DIFF8respectively. By performing signal crosstalk simulation analysis on the structure shown inFIG.21, NEXT simulation curves of DIFF3, DIFF5, and DIFF7may be separately obtained, as shown inFIG.22, and FEXT simulation curves of DIFF4, DIFF6, and DIFF8may be separately obtained, as shown inFIG.23. According to the NEXT simulation curves shown inFIG.22, it may be learned that NEXT signal strengths are respectively −50.1 dB/−53.7 dB/−60.3 dB/@15 GHz. For details, refer to Table 2. According to the FEXT simulation curves shown inFIG.23, it may be learned that FEXT signal strengths are respectively −42.6 dB/−44.3 dB/−50.5 dB/@15 GHz. For details, refer to Table 2.

It can be learned from Table 2 that, compared with a conventional solution of designing a ground crimping hole, the solution of designing a ground crimping hole shown inFIG.9can reduce NEXT by about 6 to 10 dB/@15 GHz, and can reduce FEXT by about 6.5 to 14.5 dB/@15 GHz. In other words, compared with the conventional solution of designing a ground crimping hole, the solution of designing a ground crimping hole shown inFIG.9significantly reduces signal crosstalk between two adjacent pairs of signal crimping holes40.

To further reduce the signal crosstalk between the two adjacent pairs of signal crimping holes40, on a basis of Embodiment 1 and Embodiment 2, as shown inFIG.6orFIG.11, in two adjacent rows of crimping holes, in the first direction, any pair of signal crimping holes40in a current row and any pair of signal crimping holes40in a next row are staggered, and a ground crimping hole50in the current row and a ground crimping hole50in the next row are staggered. Staggering any pair of signal crimping holes50in the two adjacent upper and lower rows can increase a distance between two adjacent upper and lower pairs of signal crimping holes40in the two adjacent upper and lower rows, and therefore can reduce signal crosstalk between the two adjacent upper and lower pairs of signal crimping holes40in the two adjacent upper and lower rows.

An embodiment of this application further provides a communications device, including the printed circuit board provided in the foregoing embodiments and a connector that fits with the printed circuit board. A signal crimping pin in the connector is inserted into a signal crimping hole of the printed circuit board, and a ground crimping pin in the connector is inserted into a ground crimping hole. Because the communications device uses the printed circuit board described in the foregoing embodiments, the communications device has advantages of the foregoing printed circuit board. For details, refer to the foregoing related descriptions. Details are not described herein again.

In the descriptions of this specification, reference to descriptions of terms “one implementation”, “some implementations”, “example implementations”, “example”, “specific example”, “some examples”, or the like means specific features, structures, materials, or features described with reference to the implementations or examples are included in at least one implementation or example of this application. In this specification, the foregoing example expressions of the terms are not necessarily a same embodiment or example. In addition, the described specific features, structures, materials, or features may be combined in a proper manner in any one or more of the implementations or examples.