Circuit board

Abstract

The present invention relates to a circuit board, which includes a substrate, a first conductive layer disposed on the first surface of the substrate, and a second conductive layer disposed on the second surface of the substrate. A plurality of first through holes penetrating through its upper surface and lower surface are formed on the first conductive layer. The maximum value of the distance S between any two points on the contour of the cross-section of the first through hole is less than the wavelength λ of the electromagnetic wave incident on the first through hole. The second conductive layer is electrically connected to the first conductive layer. By providing the first conductive layer and the second conductive layer with the first through holes, diffraction occurs when the electromagnetic wave enters the first through hole and reflection occurs when the electromagnetic wave enters the surface of the second conductive layer, thereby realizing multi-directional propagation of the electromagnetic wave.

Description

Technical Field

[0001] The present invention relates to the field of communication technologies, and particularly to a circuit board. Background Art

[0002] Antennas are widely used in fields such as radio communication, television, and broadcasting. As devices for transmitting and receiving electromagnetic waves, antennas play a crucial role in radio communication. Electromagnetic waves have the physical property of propagating in a straight line. To meet the actual needs of communication, it is necessary to transmit or receive electromagnetic waves from all directions. If multi-angle transmitting or receiving antennas are installed at the electromagnetic wave emission source, the volume of the antennas is relatively large, resulting in a complex structure and high cost. Therefore, there is an urgent need to improve and optimize the circuit boards used in existing antennas. Summary of the Invention

[0003] The object of the present invention is to provide a circuit board that can cause electromagnetic waves to diffract and reflect, achieving multi-directional propagation.

[0004] To achieve this purpose, the present invention adopts the following technical solutions:

[0005] A provided circuit board includes a substrate, a first conductive layer provided on the first surface of the substrate, and a second conductive layer provided on the second surface of the substrate. A plurality of first through-holes penetrating through its upper and lower surfaces are formed on the first conductive layer. The maximum value of the distance S between any two points on the contour of the cross-section of the first through-hole is less than the wavelength λ of the electromagnetic wave incident into the first through-hole. The second conductive layer is electrically connected to the first conductive layer.

[0006] Further, the substrate is provided with a second through-hole, and a conductive medium is provided in the second through-hole. The first conductive layer and the second conductive layer are electrically connected through the conductive medium.

[0007] Further, the conductive medium is one or a combination of more than one of copper, nickel, silver, gold, tin, zinc, lead, chromium, molybdenum, graphite, copper paste, solder paste, carbon nanotubes, graphene.

[0008] Further, the first through-hole is any one or a combination of two or more of a round hole, a square hole, an oval hole, and a special-shaped hole.

[0009] Further, the distance between any two points on the contour of the cross-section of the first through-hole is less than one percent of the wavelength λ of the electromagnetic wave.

[0010] Further, the opening ratio of the first conductive layer is 1% - 99%.

[0011] Further, along at least one direction of the substrate, a plurality of the first through-holes are arranged in a trend that the aperture size is larger in the middle and smaller on both sides.

[0012] Further, a plurality of third through holes penetrating the upper and lower surfaces are formed in the substrate, and the third through holes are correspondingly arranged with the first through holes.

[0013] Further, the circuit board further includes an antenna circuit for transmitting and / or receiving electromagnetic waves, and the antenna circuit is arranged on the substrate.

[0014] Further, an insulating layer is provided on one side of the substrate close to the first conductive layer, and the antenna circuit is located between the substrate and the insulating layer.

[0015] Advantages of the present invention compared with the prior art:

[0016] For the circuit board of the present invention, by providing the first conductive layer and the second conductive layer provided with the first through holes, diffraction occurs when the electromagnetic wave enters the first through hole and reflection occurs when the electromagnetic wave enters the surface of the second conductive layer, thereby realizing multi-directional propagation of the electromagnetic wave. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a cross-sectional view of the circuit board according to an embodiment of the present invention.

[0018] Figure 2 is a top view schematic diagram of the circuit board according to an embodiment of the present invention.

[0019] Figure 3 is a top view schematic diagram of the circuit board according to another embodiment of the present invention.

[0020] Figure 4 is a top view schematic diagram of the circuit board according to still another embodiment of the present invention.

[0021] Figure 5 is a cross-sectional view of the circuit board according to an embodiment of the present invention.

[0022] Figure 6 is a cross-sectional view of the circuit board according to another embodiment of the present invention.

[0023] In the figure:

[0024] 1. Substrate; 10. First conductive layer; 101. First through hole; 11. Second conductive layer; 12. Second through hole; 13. Third through hole; 2. Antenna circuit; 3. Insulating layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] In order to make the technical problems solved by the present invention, the technical solutions adopted and the achieved technical effects clearer, the technical solutions of the present invention will be further described below with reference to the drawings and through specific embodiments.

[0026] As Figure 1As shown in the figure, a circuit board provided by the present invention includes a substrate 1, a first conductive layer 10 disposed on the first surface of the substrate 1, and a second conductive layer 11 disposed on the second surface of the substrate 1. A plurality of first through holes 101 penetrating through its upper and lower surfaces are formed on the first conductive layer 10. The maximum value of the distance S between any two points on the contour of the cross-section of the first through hole 101 is less than the wavelength λ of the electromagnetic wave incident on the first through hole 101. The second conductive layer 11 is electrically connected to the first conductive layer 10. It can be understood that the wavelength λ of the electromagnetic wave used in communication is generally between 0.1 mm and 1 m. The electromagnetic wave has the characteristic of straight-line propagation, resulting in a relatively narrow signal propagation range. By providing the first conductive layer 10 with the first through holes 101 and the second conductive layer 11, when the electromagnetic wave enters the first through hole 101, diffraction occurs, and when the electromagnetic wave enters the surface of the second conductive layer 11, reflection occurs. After diffraction and / or reflection, the propagation direction of the electromagnetic wave changes, thereby realizing the multi-directional propagation of the electromagnetic wave.

[0027] It should be noted that the distance S between any two points on the contour of the cross-section of the first through hole 101 is the straight-line distance between any two points on the hole contour line of the cross-section of the first through hole 101.

[0028] In this embodiment, the first surface is the upper surface of the substrate 1, and the second surface is the lower surface of the substrate 1. The second conductive layer 11 is used for grounding and reflecting electromagnetic waves. The second conductive layer 11 is electrically connected to the first conductive layer 10, which can improve the lightning protection ability and anti-interference ability of the circuit board. The side of the second conductive layer 11 close to the first conductive layer 10 is the reflection surface. When the electromagnetic wave enters the first conductive layer 10, the electromagnetic wave passes through the first through hole 101 and diffraction occurs, and the propagation direction spreads disorderly around the hole. The diffracted electromagnetic wave passes through the substrate 1 and enters the second conductive layer 11, and reflection occurs on its reflection surface, changing the propagation direction and propagating towards the first conductive layer 10 side. The reflected electromagnetic wave enters the first through hole 101 again and diffraction occurs, and the propagation direction spreads disorderly around the hole, expanding the propagation range of the electromagnetic wave.

[0029] Specifically, the materials of the first conductive layer 10 and the second conductive layer 11 need to have electrical conductivity and electromagnetic shielding properties. The materials of the first conductive layer 10 and the second conductive layer 11 are one or a combination of copper, nickel, silver, gold, tin, zinc, lead, chromium, molybdenum, or conductive rubber materials, or other conductive materials. In this embodiment, the first conductive layer 10 and the second conductive layer 11 are metal layers, preferably copper foils.

[0030] Specifically, the substrate 1 is provided with a second through hole 12, and a conductive medium is arranged in the second through hole 12. The first conductive layer 10 and the second conductive layer 11 are electrically connected through the conductive medium. It can be understood that the function of the conductive medium is to conduct the first conductive layer 10 and the second conductive layer 11. Therefore, the material of the conductive medium and the connection form between the conductive medium and the first conductive layer 10 and the second conductive layer 11 can be flexibly selected according to the actual situation.

[0031] Specifically, the conductive medium is one or a combination of more than one of copper, nickel, silver, gold, tin, zinc, lead, chromium, molybdenum, graphite, copper paste, solder paste, carbon nanotubes, graphene. The conductive medium can be arranged along the inner wall of the second through hole 12, or can be filled in the second through hole 12. For example, solder paste is filled to connect the solder paste in the hole with the first conductive layer 10 and the second conductive layer 11. In this embodiment, the conductive medium is a copper foil, and the copper foil is arranged on the inner wall of the second through hole 12. The copper foil has a light weight, which is beneficial to reducing the overall weight of the circuit board. At the same time, the two ends of the second through hole 12 can respectively abut against the first conductive layer 10 and the second conductive layer 11, and the electrical connection between the first conductive layer 10 and the second conductive layer 11 is realized through the conductive medium; holes corresponding to the second through hole 12 can also be respectively opened on the first conductive layer 10 and the second conductive layer 11, and the electrical connection between the first conductive layer 10 and the second conductive layer 11 is realized through the conductive medium.

[0032] Specifically, a plurality of second through holes 12 are provided, and the plurality of second through holes 12 are spaced apart and distributed on the circumference of the substrate 1. Arranging a plurality of second through holes 12 can increase the connection area between the conductive medium and the first conductive layer 10 and the second conductive layer 11 respectively, and improve the reliability of the connection between the first conductive layer 10 and the second conductive layer 11.

[0033] As Figure 2 shown, the first through hole 101 is any one or a combination of two or more of a round hole, a square hole, an oval hole, and a special-shaped hole. It can be understood that the first through hole 101 can be flexibly selected according to the processing difficulty, as long as it satisfies that the electromagnetic wave diffracts after entering the first through hole 101. In this embodiment, the maximum value of the distance S between any two points on the contour of the cross section of the first through hole 101 is less than the wavelength λ of the radio wave. For example, when the first through hole 101 is a round hole, the maximum value of the distance S between any two points is the diameter of the first through hole 101; when the first through hole 101 is a rectangular hole, the maximum value of the distance S between any two points is the diagonal distance of the first through hole 101; when the first through hole 101 is a combination of a round hole and a rectangular hole, the maximum value of the distance S between any two points is the larger of the diameter of the round hole and the diagonal distance of the rectangular hole.

[0034] As a preferred solution, the first through hole 101 in this embodiment is a round hole. The round hole is easy to process, and the hole wall is smooth, and it is not easy to damage the first conductive layer 10 during processing.

[0035] Specifically, the distance between any two points on the contour of the cross-section of the first through-hole 101 is less than one percent of the wavelength λ of the electromagnetic wave. It can be understood that the aperture of the first through-hole 101 is less than the wavelength λ of the electromagnetic wave, which can ensure that diffraction occurs when the electromagnetic wave is incident on the first through-hole 101. Of course, in other embodiments, a suitable size range of the first through-hole 101 can also be selected according to the actual use environment.

[0036] Specifically, the aperture ratio of the first conductive layer 10 is 1% to 99%. It can be understood that the aperture ratio is the ratio of the total cross-sectional area of a plurality of first through-holes 101 on the first conductive layer 10 to the area of the first conductive layer 10. To achieve multi-directional propagation of electromagnetic waves, it is necessary to ensure that a large number of electromagnetic waves pass through the first through-holes 101 and diffraction occurs. If the total area of the first through-holes 101 is too large, the remaining amount of the first conductive layer 10 is small, which is likely to cause the first conductive layer 10 to crack and be damaged. If the total area of the first through-holes 101 is too small, the diffracted electromagnetic waves are not sufficient to achieve multi-directional coverage. Therefore, in actual applications, the area ratio of the first through-holes 101 can be reasonably designed according to the application scenario of the circuit board.

[0037] As Figure 3 shown, along at least one direction of the substrate 1, a plurality of first through-holes 101 are arranged in a trend that the aperture size is larger in the middle and smaller on both sides. It can be understood that the aperture size of the first through-hole 101 refers to the maximum value of the distance S between any two points on the contour of the cross-section of the first through-hole 101. In this embodiment, the first through-hole 101 is preferably a circular hole, so the size of the first through-hole 101 in this embodiment is the diameter of the circular hole. That is, the diameter of the first through-hole 101 at the middle position and the diameter of the first through-hole 101 at both sides are arranged in a trend of decreasing from large to small. Different sizes of the first through-holes 101 make the intensity of the diffracted electromagnetic waves uneven when the electromagnetic wave is incident on the first through-holes 101, and the propagation directions of the electromagnetic waves passing through the first through-holes 101 are different, making the propagation direction of the electromagnetic waves more dispersed. In this embodiment, the size of the first through-hole 101 is larger in the middle and smaller on both sides along the length direction of the substrate 1, so that the diffraction of the electromagnetic waves on both sides is stronger than that at the middle position, and the intensity and propagation range of the electromagnetic waves in the peripheral area of the circuit board can be selectively enhanced.

[0038] In another embodiment, as Figure 4 shown, along the first direction and the second direction of the substrate 1 respectively, a plurality of first through-holes 101 are arranged in a trend that the aperture size is larger in the middle and smaller on both sides, and the first direction is perpendicular to the second direction. It can be understood that the aperture size of the first through-hole 101 is larger in the middle and smaller on both sides along two mutually perpendicular directions, which can make the intensity distribution of the diffracted electromagnetic waves form a similar circle, and the intensity and propagation range of the electromagnetic waves in the peripheral area of the circuit board can be selectively enhanced.

[0039] As shown Figure 5 in FIG. 3, a plurality of third through holes 13 penetrating the upper and lower surfaces are formed in the substrate 1, and the third through holes 13 are correspondingly arranged with the first through holes 101. It can be understood that by forming the third through holes 13 in the substrate 1, the medium between the first conductive layer 10 and the second conductive layer 11 is the substrate layer and air, and their refractive indexes are different, so that when the electromagnetic wave passes through the substrate 1, refraction occurs, further changing the propagation direction.

[0040] As shown Figure 6 in FIG. 4, the circuit board further includes an antenna circuit 2 for transmitting and / or receiving electromagnetic waves, and the antenna circuit 2 is arranged on the substrate 1. In this embodiment, the first conductive layer 10 provided on the first surface and the second conductive layer 11 provided on the second surface are oppositely arranged and located on both sides of the antenna circuit 2. The electromagnetic wave emitted by the antenna circuit 2 cannot pass through the second conductive layer 11 and is reflected at the reflection surface of the second conductive layer 11. After reflection, the propagation direction of the electromagnetic wave is changed and it enters the first conductive layer 10, so that the electromagnetic wave emitted by the antenna circuit 2 is concentrated and propagated outward from the first through holes 101 of the first conductive layer 10, improving the electromagnetic wave intensity in the corresponding area.

[0041] Specifically, an insulating layer 3 is provided on one side of the substrate 1 close to the first conductive layer 10, and the antenna circuit 2 is located between the substrate 1 and the insulating layer 3. It can be understood that the insulating layer 3 plays a protective role for the antenna circuit 2. In this embodiment, the material of the substrate 1 includes but is not limited to a PI board. The second conductive layer 11 is provided on the substrate 1 by sputtering or electroplating, and the antenna circuit 2 is provided on the side of the substrate 1 away from the second conductive layer 11 by etching. A cover film is further provided on one side of the substrate 1 close to the antenna circuit 2 and is bonded to the insulating layer 3 to play a protective role for the antenna circuit 2.

[0042] The remarkable effect of this embodiment is that: by providing the first conductive layer 10 and the second conductive layer 11 with the first through holes 101 formed in the substrate 1, when the electromagnetic wave enters the first through holes 101, diffraction occurs, and when the electromagnetic wave enters the surface of the second conductive layer 11, reflection occurs, so that the propagation direction diverges, expanding the propagation range of the electromagnetic wave. At the same time, at least along one direction of the substrate 1, the first through holes 101 are arranged in a trend that the size of the hole diameter is larger in the middle and smaller on both sides, so that when the electromagnetic wave diffracts after entering the first through holes 101, the intensity is uneven, and the electromagnetic wave intensity and propagation range in the peripheral area of the circuit board can be selectively enhanced.

[0043] The above content is only a preferred embodiment of the present invention. For those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. The content of this specification should not be construed as a limitation to the present invention.

Claims

1. A circuit board, characterized in that, It includes a substrate (1), a first conductive layer (10) disposed on the first surface of the substrate (1), and a second conductive layer (11) disposed on the second surface of the substrate (1). A plurality of first through-holes (101) penetrating through its upper and lower surfaces are formed on the first conductive layer (10). The maximum value of the distance S between any two points on the contour of the cross-section of the first through-hole (101) is less than the wavelength λ of the electromagnetic wave incident on the first through-hole (101). The second conductive layer (11) is electrically connected to the first conductive layer (10). When the electromagnetic wave is incident on the first through-hole (101), diffraction occurs, and when the electromagnetic wave is incident on the surface of the second conductive layer (11), reflection occurs.

2. The circuit board according to claim 1, characterized in that, The substrate (1) is provided with a second through-hole (12), and a conductive medium is provided in the second through-hole (12). The first conductive layer (10) and the second conductive layer (11) are electrically connected through the conductive medium.

3. The circuit board according to claim 2, characterized in that, The conductive medium is one or a combination of more than one of copper, nickel, silver, gold, tin, zinc, lead, chromium, molybdenum, graphite, copper paste, solder paste, carbon nanotubes, graphene.

4. The circuit board according to claim 1, characterized in that, The first through-hole (101) is any one or a combination of two or more of a round hole, a square hole, an elliptical hole, and a special-shaped hole.

5. The circuit board according to claim 1, characterized in that, The distance between any two points on the contour of the cross-section of the first through-hole (101) is less than one percent of the wavelength λ of the electromagnetic wave.

6. The circuit board according to claim 1, characterized in that, The opening ratio of the first conductive layer (10) is 1% - 99%.

7. The circuit board according to claim 1, characterized in that, Along at least one direction of the substrate (1), a plurality of the first through-holes (101) are arranged in a trend of being larger in the middle and smaller on both sides according to the aperture size.

8. The circuit board according to claim 1, characterized in that, A plurality of third through-holes (13) penetrating through the upper and lower surfaces of the substrate (1) are formed on the substrate (1), and the third through-holes (13) are arranged corresponding to the first through-holes (101).

9. The circuit board according to claim 1, characterized in that, The circuit board further includes an antenna circuit (2) for transmitting and / or receiving electromagnetic waves, and the antenna circuit (2) is disposed on the substrate (1).

10. The circuit board according to claim 9, characterized in that, An insulating layer (3) is provided on one side of the substrate (1) close to the first conductive layer (10), and the antenna circuit (2) is located between the substrate (1) and the insulating layer (3).

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