Printed circuit board and electronic device

Abstract

The utility model relates to the technical field of circuit boards, and discloses a printed circuit board and an electronic device with the printed circuit board. The circuit board comprises a substrate and a circuit pattern printed on the substrate, and an acute included angle is formed between the whole circuit pattern and a glass fiber bundle of a dielectric layer of the substrate. According to the printed circuit board provided by the embodiment of the utility model, by rotating the circuit pattern, an acute included angle is formed between most of the wires in the circuit pattern and the glass fiber bundles of the dielectric layer, so that most of the wires in the circuit pattern can uniformly pass through the windows between the glass fiber bundles; and the delay inequality between the wires caused by the glass fiber effect is reduced, so that the delay inequality in the differential pair of the differential wire is reduced, and the performance of the circuit is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit boards, and particularly relates to a printed circuit board and an electronic device. Background Art

[0002] When electromagnetic signals or optical signals are transmitted through a transmission medium, there will be a time delay. The time delay (TD) = transmission length (L) / propagation speed (VPCB), where the propagation speed (VPCB) = speed of light in vacuum / effective dielectric constant. From this, it can be seen that the time delay of signals in the transmission medium is affected by the dielectric constant of the dielectric layer of the circuit board. The dielectric layer of the substrate of the existing PCB circuit board is mostly made by filling the windows between the glass fiber bundles in the glass fiber cloth with resin. The dielectric constant (Er) on the glass fiber bundle is greater than the dielectric constant at the window between the glass fiber bundles, that is, there is a glass fiber effect. The glass fiber effect will cause the signal transmission time delays on the traces close to the glass fiber bundle and the traces passing through the windows between the glass fiber bundles to be inconsistent. As Figure 1 shown, it may cause a large differential pair internal delay difference in the differential lines on the circuit board, affecting the performance of the circuit. Summary of the Utility Model

[0003] In order to overcome the deficiencies of the prior art, the purpose of the utility model is to provide a printed circuit board that can reduce the influence of the glass fiber effect on the differential pair internal time delay difference in the circuit.

[0004] To solve the above problems, the technical solution adopted by the utility model is as follows: A printed circuit board includes a substrate and a circuit pattern printed on the substrate. The whole of the circuit pattern has an acute angle with the glass fiber bundles of the dielectric layer of the substrate.

[0005] Compared with the prior art, the beneficial effect of the utility model is that by rotating the circuit pattern at a certain angle, most of the traces in the circuit pattern can evenly pass through the glass fiber bundles and the windows between the glass fiber bundles in the dielectric layer of the substrate, thereby reducing the difference in dielectric constants between the resin filled between the glass fiber bundles and the windows, which causes a large time delay difference between the circuit traces. Thus, the differential pair internal time delay difference of the differential lines can be controlled within a suitable range, avoiding the influence of the differential pair internal time delay difference on the circuit performance.

[0006] For the above-mentioned printed circuit board, the angle between the whole of the circuit pattern and the glass fiber bundles of the dielectric layer of the substrate is greater than or equal to 5 degrees.

[0007] For the above-mentioned printed circuit board, the angle between the whole of the circuit pattern and the glass fiber bundles of the dielectric layer of the substrate is less than or equal to 8 degrees.

[0008] An electronic device, characterized in that it includes the above-mentioned printed circuit board.

[0009] The present utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. Description of the Drawings

[0010] Figure 1 It is an enlarged structural schematic diagram of the dielectric layer of an existing printed circuit board;

[0011] Figure 2 It is an enlarged structural schematic diagram of the dielectric layer of the printed circuit board according to the embodiment of the present utility model;

[0012] Figure 3 It is a structural schematic diagram of a printed circuit board panel according to the embodiment of the present utility model;

[0013] Figure 4 It is a structural schematic diagram of a printed circuit board panel for testing the intra-pair delay in a differential pair at different rotation angles;

[0014] Figure 5 It is a curve graph of the experimental results of the intra-pair delay in a differential pair at different rotation angles. Specific Embodiments

[0015] The embodiments of the present utility model will be described in detail below. Referring to Figure 2 , the embodiments of the present utility model provide a printed circuit board, including a substrate and a circuit pattern printed on the substrate, wherein the whole of the circuit pattern forms an acute angle with the glass fiber bundles of the dielectric layer of the substrate. In the printed circuit board according to the embodiment of the present utility model, since the circuit pattern forms an angle with the glass fiber bundles of the dielectric layer, most of the traces in the circuit pattern will also form an angle with the glass fiber bundles, so that most of the traces in the circuit pattern can evenly pass through the window between the peeling fiber bundles and the glass fiber bundles, thereby avoiding different signal delays between the traces close to the glass fiber bundles and the traces passing through the window. The printed circuit board according to the embodiment of the present utility model can reduce the intra-pair delay difference of the differential lines in the circuit pattern, thereby improving the synchronization degree of the signals in the differential lines, reducing the differential loss, and avoiding the influence of the glass fiber effect on the circuit performance.

[0016] Referring to Figure 3 , in actual production, since the glass fiber bundles in the dielectric layer usually intersect along the horizontal and vertical directions of the circuit board to form a glass fiber network, in the process of panel production, only the circuit pattern to be produced needs to be rotated by a certain angle relative to the substrate, so that the traces in the circuit pattern form an angle with the horizontal or vertical glass fiber bundles.

[0017] Referring to Figure 4, in order to test the differences at different rotation angles, the circuit patterns of multiple commonly used differential lines are rotated by different angles and then assembled on a large board for production to ensure production in the same batch during the production process and avoid the influence of environmental differences between different batches on the test results. The differential lines designed with three winding methods are in the same single board, ensuring that the materials, laminations, and reference layers are exactly the same. The test results are as Figure 5 shown. It can be seen from Figure 5 that for the differential lines rotated by 5 degrees, 10 degrees, and 15 degrees compared to the non-rotated differential lines, the differential loss decreases for signals at different frequencies. Moreover, the larger the rotation angle, the greater the reduction in differential loss and the smaller the intra-pair delay difference. Among them, between 5 degrees and 8 degrees of rotation, the loss is reduced by about 10%. When rotated by 15 degrees, the loss is reduced by about 15%. Thus, it can be known that when not rotated, the intra-pair delay difference of the differential lines is on average within 20 ps. As long as the rotation angle of the circuit pattern is greater than or equal to 5 degrees, the overall circuit pattern can have an angle of 5 degrees with the glass fiber bundle, and the intra-pair delay difference can be controlled within 1 ps.

[0018] Since in the production process of the circuit board, in order to improve production efficiency, the production method of assembling boards is mostly adopted, the rotation angle of the circuit pattern should not be too large. If the rotation angle of the circuit pattern is too large, it may reduce the number of products on the large board and affect the utilization rate of the assembled board, thereby increasing the production cost of the product. Therefore, it is advisable to control the rotation angle of the circuit pattern within 5 - 8 degrees. This can control the intra-pair delay within 1 ps while still ensuring the utilization rate of the assembled board and not increasing the production cost.

[0019] The electronic device of the embodiment of the present invention includes the above-mentioned printed circuit board, which can control the differential loss caused by the glass fiber effect, improve the circuit performance, and thus improve the product performance.

[0020] It should be noted that in the description of the present utility model, if there is any reference to the orientation description, such as the orientation or positional relationship indicated by up, down, front, back, left, right, etc., it is all based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed or operated in a specific orientation, and should not be construed as a limitation to the present utility model.

[0021] In the description of the present utility model, the meaning of several is one or more, and the meaning of multiple is two or more. Understandings such as greater than, less than, exceeding, etc. do not include the present number, and understandings such as above, below, within, etc. include the present number. If there is a description of the first or the second, etc., it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0022] In the description of the present utility model, unless otherwise clearly defined, terms such as "arrangement", "installation", "connection", etc. shall be understood in a broad sense, and those skilled in the relevant technical field can reasonably determine the specific meanings of the above terms in the present utility model in combination with the specific content of the technical solution.

[0023] The above-mentioned embodiments are only the preferred embodiments of the present utility model, and cannot be used to limit the scope of protection of the present utility model. Any non-substantial changes and substitutions made by those skilled in the art on the basis of the present utility model fall within the scope of protection required by the present utility model.

Claims

1. A printed circuit board, characterized in that, It includes a substrate and a circuit pattern printed on the substrate, and there is an acute angle between the whole of the circuit pattern and the glass fiber bundle of the dielectric layer of the substrate.

2. The printed circuit board according to claim 1, characterized in that, The angle between the whole of the circuit pattern and the glass fiber bundle of the dielectric layer of the substrate is greater than or equal to 5 degrees.

3. The printed circuit board according to claim 2, wherein The angle between the whole of the circuit pattern and the glass fiber bundle of the dielectric layer of the substrate is less than or equal to 8 degrees.

4. An electronic device, characterized in that, It includes a printed circuit board according to any one of claims 1 to 3.

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