Printed Circuit Board

Abstract

The present invention discloses a printed circuit board. The printed circuit board includes: a first conductive layer disposed on one side of the printed circuit board; a second conductive layer disposed on the other side of the printed circuit board; a signal line layer disposed between the first conductive layer and the second conductive layer; a signal hole, at least a part of the inner wall of the signal hole is provided with a signal metal layer, and the signal metal layer is electrically connected to the signal line layer; the signal metal layer is spaced apart from the side of the printed circuit board close to the first conductive layer; wherein, the signal hole is used to insert a signal pin of a connector so that the signal pin contacts the signal metal layer and is electrically connected to the signal line layer. With the above structure, the present invention can reduce the ineffective signal metal layer of the signal hole, reduce the shunt and bifurcation paths in signal transmission, thereby reducing the impedance fluctuation of the signal hole and improving the signal transmission bandwidth and signal transmission quality.

Description

Technical Field

[0001] The present invention is applied to the technical field of printed circuit boards. Background Art

[0002] PCB (Printed Circuit Board), also known as printed circuit board or printed circuit board, is an important electronic component with wide application. It is the support body of electronic components and also the carrier of electrical connection of electronic components.

[0003] When two printed circuit boards are connected and signal transmitted mainly through a backplane connector, the signal hole at the connector plug-in is the necessary place for signal transmission. The structure of the connector plug-in signal hole will affect the signal interconnection between the two circuit boards, and thus affect the bandwidth and quality of signal transmission.

[0004] The signal hole structure of traditional printed circuit boards will lay a large copper sheet around the signal hole as a reference ground. The connector signal hole structured in this way has large impedance fluctuations, poor matching, and low transmission signal bandwidth. In severe cases, it will cause the signal bit error rate at the signal receiving end to increase, resulting in signal restoration errors. Summary of the Invention

[0005] The present invention provides a printed circuit board to solve the problems in the prior art of large impedance fluctuation of signal holes of the printed circuit board and low signal bandwidth.

[0006] To solve the above technical problems, the present invention provides a printed circuit board, comprising: a first conductive layer, arranged on one side of the printed circuit board; a second conductive layer, arranged on the other side of the printed circuit board; a signal line layer, arranged between the first conductive layer and the second conductive layer; a signal hole, wherein at least a portion of the inner wall of the signal hole is provided with a signal metal layer, and the signal metal layer is electrically connected to the signal line layer; the signal metal layer is spaced apart from a side of the printed circuit board close to the first conductive layer; wherein the signal hole is used to insert a signal pin of a connector so that the signal pin contacts the signal metal layer and is electrically connected to the signal line layer.

[0007] The signal metal layer of the signal hole is spaced apart from a side of the printed circuit board close to the second conductive layer.

[0008] The distance between the end of the signal metal layer of the signal hole close to the second conductive layer and the signal line layer is less than 10 mil.

[0009] Among them, the signal line layer includes a surrounding part, a connecting part and a routing part; the surrounding part is arranged around the signal hole; one end of the connecting part is connected to the surrounding part, and the other end of the connecting part is connected to the routing part; one end of the routing part is connected to the connecting part, and the routing part and the projection of other conductive layers of the printed circuit board except the signal line layer on the first plane are overlapped.

[0010] Among them, the width of the connecting member is greater than the width of the wiring member.

[0011] Among them, the projections of the surrounding member and the connecting member on other conductive layers of the printed circuit board except the signal line layer do not overlap.

[0012] Among them, one shielding hole is symmetrically arranged on each side of each signal hole.

[0013] Among them, every two adjacent signal holes form a signal pair; four grounding holes are symmetrically arranged around each signal pair.

[0014] Among them, the center point of each signal pair coincides with the center points of the corresponding four shielding holes; the center point of each signal pair coincides with the center points of the corresponding four grounding holes.

[0015] Among them, a shielding metal layer is provided on the inner wall of the shielding hole, the shielding metal layer penetrates through the printed circuit board and is connected to other conductive layers of the printed circuit board except the signal line layer; a grounding metal layer is provided on the inner wall of the grounding hole, the grounding metal layer penetrates through the printed circuit board and is connected to other conductive layers of the printed circuit board except the signal line layer.

[0016] Among them, the distance between the end of the signal hole close to the first conductive layer and the first conductive layer is greater than or equal to 0.5 millimeters.

[0017] The beneficial effects of the present invention are as follows: Different from the prior art, in the printed circuit board of the present invention, a signal metal layer is at least partially provided on the inner wall of the signal hole, and the signal metal layer is electrically connected to the signal line layer, while the signal metal layer is spaced from the side of the printed circuit board close to the first conductive layer. Therefore, when the printed circuit board is connected to the signal pins of the connector, the signal metal layer of the signal hole can contact the thicker middle part of the signal pin to achieve electrical connection and signal transmission, and at the same time, the length of the signal metal layer of the signal hole can be shortened to avoid the occurrence of shunt and bifurcation of the redundant signal metal layer, which affects the impedance, thereby reducing the fluctuation of the via impedance and improving the signal transmission bandwidth and signal transmission quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic structural diagram of an embodiment of the printed circuit board of the present invention;

[0019] Figure 2 is Figure 1 a top view structural diagram of the printed circuit board in the embodiment;

[0020] Figure 3 is Figure 1 a front view structural diagram of the printed circuit board in the embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, then such directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If this specific posture changes, then the directional indications will also change accordingly.

[0023] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, then such descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0024] Please refer to Figures 1-3 , Figure 1 which is a schematic structural diagram of an embodiment of a printed circuit board of the present invention. Figure 2 is Figure 1 a top view structural diagram of the printed circuit board in the embodiment, Figure 3 is Figure 1 a front view structural diagram of the printed circuit board in the embodiment.

[0025] The printed circuit board 100 of this embodiment at least includes a first conductive layer 101, a second conductive layer 102, a signal line layer 104, and a signal hole 103.

[0026] The first conductive layer 101 is disposed on one side of the printed circuit board 100, and the second conductive layer 102 is disposed on the other side of the printed circuit board 100, that is, the first conductive layer 101 and the second conductive layer 102 are respectively disposed on opposite sides of the printed circuit board 100. And the signal line layer 104 is disposed between the first conductive layer 101 and the second conductive layer 102.

[0027] At least a part of the inner wall of the signal hole 103 is provided with a signal metal layer (not marked in the figure), and the signal metal layer is electrically connected to the signal line layer 104; the signal metal layer and the side of the printed circuit board 100 close to the first conductive layer 101 are spaced apart; wherein, the signal hole 103 is used to insert the signal pin of the connector, so that the signal pin contacts the signal metal layer and is electrically connected to the signal line layer 104, thereby realizing signal transmission between the connector and the signal line layer 104 through the signal hole 103.

[0028] At least a part of the inner wall of the signal hole 103 is metallized, and the middle of the hole is hollowed out for inserting the signal pin of the connector.

[0029] The printed circuit board 100 of this embodiment can be applied to all products using connectors for connection, including communication backplanes, servers, and common circuit boards, etc.

[0030] In a specific application scenario, the signal hole 103 can extend to the first conductive layer 101 of the printed circuit board 100, but the signal metal layer of the signal hole 103 does not extend along with the inner wall of the signal hole 103, so that the signal metal layer of the signal hole 103 is spaced apart from the first conductive layer 101 of the printed circuit board 100. Since the shape of the signal pin of the connector is thick in the middle and thin at both ends, when the signal pin of the connector is inserted into the signal hole 103, only the thicker middle part of the signal pin abuts against the signal metal layer of the signal hole 103, thereby realizing electrical connection and signal transmission, and its thinner ends do not realize the function of electrical connection with the signal hole 103. Therefore, when the signal metal layer of the signal hole 103 is spaced apart from the first conductive layer 101 of the printed circuit board 100, it can not only ensure that the thicker middle part of the signal pin contacts the signal metal layer of the signal hole 103 to realize electrical connection and signal transmission, but also reduce the ineffective setting that the signal metal layer at the end close to the first conductive layer 101 cannot contact the thinner end of the signal pin, thereby reducing the occurrence of shunt and bifurcation of the signal metal layer and affecting the impedance.

[0031] In another specific application scenario, the signal hole 103 and its signal metal layer are both spaced apart from the first conductive layer 101 of the printed circuit board 100, and the signal hole 103 can be arranged at the bottom of the groove on the printed circuit board 100, so that the signal pin passes through the groove and is inserted into the signal hole 103 for abutting, thereby enabling the signal pin to contact the signal metal layer of the signal hole 103 to realize electrical connection and signal transmission, and at the same time, the length of the signal metal layer of the signal hole 103 can be shortened to avoid the occurrence of shunt and bifurcation of the redundant signal metal layer and affecting the impedance.

[0032] With the above structure, in the printed circuit board of this embodiment, a signal metal layer is provided at least partially on the inner wall of the signal hole, and the signal metal layer is electrically connected to the signal line layer. The signal metal layer is spaced from the side of the printed circuit board close to the first conductive layer. Thus, when the printed circuit board is connected to the signal pins of the connector, the signal metal layer of the signal hole can contact the thicker middle part of the signal pins to achieve electrical connection and signal transmission. At the same time, the length of the signal metal layer of the signal hole can be shortened, avoiding the situation where the redundant signal metal layer causes shunt and bifurcation, which affects the impedance. Furthermore, the fluctuation of the via impedance can be reduced, and the signal transmission bandwidth and signal transmission quality can be improved.

[0033] In other embodiments, the signal metal layer of the signal hole 103 is spaced from the side of the printed circuit board 100 close to the second conductive layer 102. During the connection process between the printed circuit board 100 and the signal pins of the connector, the signal is transmitted to the signal pins of the connector through the signal line layer 104 and the signal metal layer of the signal hole 103. Therefore, when the signal metal layer of the signal hole 103 is spaced from the side of the printed circuit board 100 close to the second conductive layer 102, it can further reduce the shunt and bifurcation caused by the redundant signal metal layer, reduce the impedance fluctuation of the signal hole 103, reduce signal reflection, and improve the signal transmission bandwidth.

[0034] In a specific application scenario, the way that the signal metal layer of the signal hole 103 is spaced from the second conductive layer 102 is similar to the way that the signal metal layer of the signal hole 103 is spaced from the first conductive layer 101 in the foregoing embodiment. Please refer to the previous text and details will not be repeated here.

[0035] In other embodiments, the distance between the end of the signal metal layer of the signal hole 103 close to the second conductive layer 102 and the signal line layer 104 is less than 10 mil. That is, the distance that the signal metal layer of the signal hole 103 protrudes in the direction close to the second conductive layer 102 from the signal line layer 104 is less than 10 mil. For example, the protruding distance is 0 mil, 1 mil, 3 mil, 5 mil, 6 mil, 8 mil or 10 mil, etc. The smaller the protruding distance, the better the performance of reducing the shunt and bifurcation caused by the redundant signal metal layer.

[0036] In other embodiments, the signal line layer 104 includes a surrounding member 1041, a connecting member 1042, and a routing member 1043. Among them, the surrounding member 1041 is arranged around the corresponding signal hole 103 and is connected to the signal metal layer of the signal hole 103. One end of the connecting member 1042 is connected to the surrounding member 1041, and the other end of the connecting member 10�2 is connected to the routing member 1043; one end of the routing member 1043 is connected to the connecting member 1042, and the other end of the routing member 1043 is used for routing signal transmission.

[0037] Among them, the number of the surrounding members 1041, the connecting members 1042, and the routing members 1043 in the signal line layer 104 corresponds to the number of the signal holes 103. When the number of the signal holes 103 is multiple, there is a set of the surrounding members 1041, the connecting members 1042, and the routing members 1043 in the signal line layer 104 respectively connected to the corresponding signal holes 103 until all the signal holes 103 are connected, so as to perform signal routing.

[0038] The surrounding member 1041 is surrounded and connected to the signal metal layer of the signal hole 103, which can improve the connection quality effect between the surrounding member 1041 and the signal hole 103, improve the signal transmission effect, and reduce the occurrence of signal transmission affected by poor contact.

[0039] Among them, the routing member 1043 is overlapped and arranged with the projection of other conductive layers of the printed circuit board 100 except the signal line layer 104 on the first plane.

[0040] In other embodiments, the surrounding member 1041 and the connecting member 1042 of the signal line layer 104 are not overlapped and arranged with the projection of other conductive layers of the printed circuit board 100 except the signal line layer 104 on the first plane. Among them, the first plane is parallel to the signal line layer 104 and other conductive layers of the printed circuit board 100.

[0041] That is to say, the signal line layer 104 is spaced from other conductive layers in the printed circuit board 100, and the surrounding member 1041 and the connecting member 1042 of the signal line layer 104 are not overlapped and arranged with the projection of other conductive layers of the printed circuit board 100 except the signal line layer 104 on the first plane.

[0042] Among them, in addition to the first conductive layer 101, the second conductive layer 102, and the signal line layer 104, the conductive layers of the printed circuit board 100 may further include at least one third conductive layer 107. The third conductive layer 107 is arranged between the first conductive layer 101 and the second conductive layer 102 to realize the circuit function of the printed circuit board 100. Specifically, the number of the third conductive layers 107 can be set based on actual needs, such as 3 layers, 5 layers, or 8 layers, etc., which is not limited herein.

[0043] Then the signal line layer 104 is spaced from the first conductive layer 101, the second conductive layer 102, and the third conductive layer 107 in the printed circuit board 100, and the surrounding member 1041 and the connecting member 1042 of the signal line layer 104 are not overlapped and arranged with the projection of the first conductive layer 101, the second conductive layer 102, and the third conductive layer 107 on the first plane.

[0044] In other embodiments, the width of the connecting member 1042 of the signal line layer 104 is greater than the width of the trace member 1043. Among them, since the projection of the connecting member 1042 on the first plane does not overlap with other conductive layers of the printed circuit board 100 except the signal line layer 104, while the projection of the trace member 1043 on the first plane overlaps with other conductive layers of the printed circuit board 100 except the signal line layer 104, other conductive layers of the printed circuit board 100 except the signal line layer 104 will affect the impedance of the trace member 1043. Therefore, by setting the width of the connecting member 1042 to be greater than the width of the trace member 1043, the impedance between the connecting member 1042 and the trace member 1043 can be balanced, so that the impedance of the connecting member 1042 and the trace member 1043 is the same, and the signal transmission quality of the entire signal line layer 104 is improved.

[0045] In other embodiments, one shielding hole 106 is symmetrically arranged on each side of each signal hole 103. Among them, the axes of the signal hole 103 and the corresponding two shielding holes 106 are coplanar. In actual setting, the error between the axes of the signal hole 103 and the two shielding holes 106 on both sides can be up to 10 mil at most. Among them, when the axes of the signal hole 103 and the two shielding holes 106 are coplanar, the shielding effect of the shielding hole 106 on the signal hole 103 is better.

[0046] In other embodiments, every two adjacent signal holes 103 form a signal pair 1031, and four grounding holes 105 are symmetrically arranged around each signal pair 1031. There is at least one signal pair 1031 arranged in the printed circuit board 100, specifically, it can be 2 groups, 5 groups, 15 groups or 30 groups, etc., and it can be specifically set based on actual requirements and is not limited here.

[0047] Among them, the four grounding holes 105 are symmetrically arranged around each signal pair 1031, which can enhance the overall grounding effect of the signal holes and effectively shorten the signal return path.

[0048] In other embodiments, the center point of each signal pair 1031 coincides with the center points of the corresponding four shielding holes 106, and the center point of each signal pair 1031 coincides with the center points of the corresponding four grounding holes 105. Such a design is beneficial to the shielding between the signal hole 103 and other surrounding signals, avoiding mutual interference between signals. At the same time, it enhances the overall grounding effect of the signal hole 103, effectively shortens the signal return path, and is beneficial to improving the transmission bandwidth of the signal passing through the signal hole. The number of various holes shown in the schematic diagram of this embodiment is only for illustration based on one signal pair 1031, and does not limit the number of various holes. In other embodiments, the printed circuit board may include n signal pairs, 2n signal holes, 4n shielding holes and 4n grounding holes, where n is a positive integer.

[0049] In other embodiments, a shielding metal layer (not shown in the figure) is provided on the inner wall of the shielding hole 106. The shielding hole 106 and the shielding metal layer penetrate through the printed circuit board 100 and are connected to all other conductive layers in the printed circuit board 100 except the signal line layer 104. The shielding hole 106 is a complete through-hole, extending from the first conductive layer 101 to the second conductive layer 102, with the hole wall metallized. The middle of the hole can be hollowed out or filled with copper plugs.

[0050] A grounding metal layer (not shown in the figure) is provided on the inner wall of the grounding hole 105. The grounding hole 105 and the grounding metal layer penetrate through the printed circuit board 100 and are connected to all other conductive layers in the printed circuit board 100 except the signal line layer 104. The grounding hole 105 is a complete through-hole, extending from the first conductive layer 101 to the second conductive layer 102, with the hole wall metallized and the middle of the hole hollowed out.

[0051] In other embodiments, the distance between one end of the signal hole 103 close to the first conductive layer 101 and the first conductive layer 101 is greater than or equal to 0.5 mm. The distance between one end of the signal hole 103 close to the first conductive layer 101 and the first conductive layer 101 can be 0.5 mm, 0.8 mm, 1.0 mm, 2.0 mm, 3.0 mm, etc., and can be specifically set based on the structure of the signal pins of the connector.

[0052] In practical applications, the signal transmission path is successively the connector, the middle part of the signal pins of the connector, the hole wall of the signal hole 103, and the signal line layer 104. By setting the distance between one end of the signal hole 103 close to the first conductive layer 101 and the first conductive layer 101 to be greater than or equal to 0.5 mm, the shunt and bifurcation paths are greatly reduced during signal transmission, the signal reflection is greatly reduced, which is beneficial to improving the impedance of the signal hole 103, reducing the fluctuation of the impedance of the signal hole 103, reducing signal reflection, increasing the signal transmission bandwidth, and facilitating signal interconnection between circuit boards.

[0053] In other embodiments, the printed circuit board 100 further includes an insulating layer (not shown in the figure). The insulating layer is sequentially overlapped and adhered to each conductive layer. The insulating layer is used to support each conductive layer and the signal hole 103 and ensure the stability of each conductive layer and the signal hole 103, thereby forming the printed circuit board 100. The materials of the insulating layer include epoxy resin, polyimide, BT, ABF, ceramic matrix, etc.

[0054] With the above structure, the signal holes of the printed circuit board in this embodiment are at a distance of greater than or equal to 0.5 mm from the first conductive layer. The signal holes pass through the signal line layer and the distance between the signal holes and the signal line layer is ≤ 10 mil, which greatly reduces the shunt and bifurcation paths during signal transmission and greatly reduces signal reflection. This is beneficial to improving the impedance of the signal vias, reducing the fluctuation of the via impedance, reducing signal reflection, and increasing the signal transmission bandwidth, which is beneficial to signal interconnection between circuit boards.

[0055] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0056] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A printed circuit board, characterized in that, The printed circuit board includes: A first conductive layer disposed on one side of the printed circuit board; A second conductive layer disposed on the other side of the printed circuit board; A signal line layer disposed between the first conductive layer and the second conductive layer; the signal line layer includes a surrounding member, a connecting member, and a routing member, one end of the connecting member is connected to the surrounding member, and the other end of the connecting member is connected to the routing member; wherein, the connecting member of the signal line layer and other conductive layers of the printed circuit board except the signal line layer do not overlap in the projection on the first plane; A signal hole, at least a part of the inner wall of the signal hole is provided with a signal metal layer, and the signal metal layer is electrically connected to the signal line layer; the signal metal layer is spaced apart from the side of the printed circuit board close to the first conductive layer; Wherein, the signal hole is used to insert a signal pin of a connector so that the signal pin contacts the signal metal layer and is electrically connected to the signal line layer.

2. The printed circuit board according to claim 1, wherein The signal metal layer of the signal hole is spaced apart from the side of the printed circuit board close to the second conductive layer.

3. The printed circuit board according to claim 2, wherein The distance between the end of the signal metal layer of the signal hole close to the second conductive layer and the signal line layer is less than 10 mil.

4. The printed circuit board according to claim 1, wherein The surrounding member surrounds the signal hole; One end of the routing member is connected to the connecting member, and the routing member overlaps with the projections of other conductive layers of the printed circuit board except the signal line layer on the first plane.

5. The printed circuit board according to claim 4, wherein The width of the connecting member is greater than the width of the routing member.

6. The printed circuit board according to claim 4, wherein The surrounding member does not overlap with the projections of other conductive layers of the printed circuit board except the signal line layer on the first plane.

7. The printed circuit board according to claim 1, wherein One shielding hole is symmetrically provided on each side of each signal hole.

8. The printed circuit board according to claim 7, characterized in that, Every two adjacent signal holes form a signal pair; Four grounding holes are symmetrically provided around each signal pair.

9. The printed circuit board according to claim 8, wherein The center point of each signal pair coincides with the center points of the corresponding four shielding holes; The center point of each signal pair coincides with the center points of the corresponding four grounding holes.

10. The printed circuit board according to claim 8, wherein The inner wall of the shielding hole is provided with a shielding metal layer, and the shielding metal layer penetrates through the printed circuit board and is connected to other conductive layers of the printed circuit board except the signal line layer; The inner wall of the grounding hole is provided with a grounding metal layer, and the grounding metal layer penetrates through the printed circuit board and is connected to other conductive layers of the printed circuit board except the signal line layer.

11. The printed circuit board according to any one of claims 1-10, characterized in that, The distance between the end of the signal hole close to the first conductive layer and the first conductive layer is greater than or equal to 0.5 mm.

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