Circuit board

Abstract

The invention belongs to the technical field of electrical equipment, and discloses a circuit board which is characterized in that the circuit board comprises circuit layers serving as electromagnetic coils and insulating layers, the insulating layers comprise core board insulating layers, the circuit layers and the insulating layers are alternately stacked from inside to outside from the core board insulating layers, and magnet yoke layers made of magnetic conductive materials are embedded in the insulating layers; the insulating layer between two adjacent circuit layers is provided with a via hole, and the magnet yoke layer avoids at the via hole. The magnetic yoke layer with high magnetic flux is embedded in the insulating layer to guide a magnetic field, so that the technical effects of saving space and enhancing driving force are achieved; and the magnet yoke layer adopts an avoidance design at the conducting hole to ensure that the magnet yoke layer is not connected with the conducting circuit of the circuit board, so that the circuit resistance is not increased, and the driving force of the original coil is not weakened due to the introduction of the magnetic conductive material.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical equipment, and in particular to a circuit board. Background Art

[0002] OIS motors, short for Optical Image Stabilization Motors, are primarily used in camera modules in smartphones, cameras, and other devices. By adjusting the position of the lens or image sensor, OIS motors compensate for image blur caused by hand shake or device movement, improving the stability and clarity of photos and videos.

[0003] Common OIS motors can refer to the structure disclosed in the patent application number CN201710203714.6, including a housing, an upper gasket, an upper spring, an OIS coil group, electronic components, a magnet, a magnet frame, a lower spring and a carrier. The housing and the carrier are matched together in an upper and lower manner, and other components are arranged inside the housing and the carrier. The carrier is usually a rectangular structure, and the OIS coil group is fixed on the periphery of the carrier, and various electronic components are also installed on the carrier. The OIS motor drives the lens or sensor module to move slightly to offset the jitter through the interaction between the electromagnetic coil (OIS coil group) and the permanent magnet (magnet). The independent coil is matched with the yoke structure, which takes up a large space.

[0004] In order to meet the ultra-small size requirements of voice coil motors for electronic devices with cameras such as smartphones, the applicant proposed an improved structure in the Chinese invention application "An OIS motor coil assembly and preparation method" with application number CN202211331530.5 in 2022. A circuit board printed with a flat coil is used to replace the traditional structure in which the coil is sleeved on a carrier, and the OIS coil group is directly embedded in the PCB through a circuit printing process to reduce additional components.

[0005] However, although the coil structure has been upgraded to a flat type to save space, in order to meet the needs of different products, it is still necessary to provide a solution that can further enhance the motor driving force, thereby making improvements in many aspects such as saving space, enhancing driving force, and ensuring signal integrity. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to propose a circuit board that saves space and enhances driving force in response to the above technical status quo.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is: a circuit board, characterized in that it includes a circuit layer and an insulation layer serving as an electromagnetic coil, the insulation layer includes a core board insulation layer, the circuit layer and the insulation layer are alternately stacked from the inside to the outside starting from the core board insulation layer, and a yoke layer made of magnetic conductive material is embedded in the insulation layer; a conductive hole is opened in the insulation layer between two adjacent circuit layers, and the yoke layer is avoided at the conductive hole.

[0008] Compared to existing technologies, this invention offers the advantage of embedding the OIS coil directly into the PCB as a circuit, using the circuit layer as the electromagnetic coil. This results in a more compact overall structural layout. Furthermore, a high-magnetic yoke layer is embedded within the insulating layer to guide the magnetic field, saving space while enhancing driving force. This improves the performance of the OIS motor and enables faster and more precise lens position adjustment during optical image stabilization. Furthermore, the yoke layer employs a clearance design at the vias to prevent it from connecting to the conductive traces of the circuit board, thereby preventing increased circuit resistance and the weakening of the original coil's driving force due to the introduction of the magnetic material.

[0009] In order to further enhance the driving force, preferably, the insulation layer includes a core plate insulation layer, an interlayer insulation layer and an outer insulation layer, a yoke layer is embedded inside the core plate insulation layer and the interlayer insulation layer, and a yoke layer is pressed, coated or bonded on the surface of the outer insulation layer.

[0010] Preferably, the magnetic material is a soft ferrite or a hard ferrite. The general chemical formula of ferrite is MO·Fe2O3, where M is a divalent metal ion (such as Mn 2+ 、Zn 2+ 、Ni 2+ 、Ba 2+ 、Sr 2+ Typical soft ferrites include manganese zinc ferrite (MnZn), with a chemical formula of Mn. 0.5 Zn 0.5 Fe2O4, and nickel-zinc ferrite (NiZn), etc., are suitable for use in:

[0011] a) High-frequency transformer: switching power supply, wireless charger;

[0012] b) Inductor: filtering and energy storage element;

[0013] c) Anti-electromagnetic interference (EMI): magnetic beads, common mode choke;

[0014] d) Microwave devices: isolators, circulators (using the gyromagnetic effect).

[0015] Typical hard ferrites include barium ferrite (BaFe 12 O 19), Strontium ferrite (SrFe 12 O 19 ), etc., suitable for application in:

[0016] a) Motors and generators: automobile starting motors, power tools;

[0017] b) Speakers and sensors: core materials of magnetic circuit system;

[0018] c) Magnetic separation technology: magnetic adsorption in industrial wastewater treatment;

[0019] d) Emerging fields: 5G communication high-frequency components, new energy vehicle motors, and magnetic resonance imaging (MRI) equipment.

[0020] Preferably, the magnetic conductive material is block ferrite, and the block ferrite forms the first magnetic yoke layer;

[0021] The first magnetic yoke layer is embedded in the core plate insulating layer and the interlayer insulating layer, and is pressed against the surface of the outer insulating layer.

[0022] Preferably, the magnetic conductive material is powdered ferrite, which is mixed into the insulating material to form the second yoke layer;

[0023] The second yoke layer is embedded in the core insulating layer and the interlayer insulating layer and is disposed on the surface of the outer insulating layer.

[0024] Preferably, the magnetic conductive material is powdered ferrite;

[0025] The powdered ferrite is coated or PVD-sprayed in the core plate insulation layer, the interlayer insulation layer, and the surface of the outer insulation layer to form a third yoke layer.

[0026] Preferably, the magnetic conductive material is a sheet or film ferrite, and the sheet or film ferrite forms the fourth yoke layer;

[0027] The fourth yoke layer is pressed and embedded in the core plate insulation layer and the interlayer insulation layer, and is arranged on the surface of the outer insulation layer.

[0028] Preferably, the magnetic conductive material is rod-shaped ferrite, and the rod-shaped ferrite forms the fifth yoke layer;

[0029] The fifth magnetic yoke layer is vertically or laterally embedded in the core plate insulating layer and the interlayer insulating layer.

[0030] When the circuit board is used for an OIS motor, preferably, the thickness of the yoke layer is in the range of 20-50 μm.

[0031] When the circuit board is used for high-power wireless charging, the thickness of the yoke layer ranges from 100 to 200 μm. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic cross-sectional view of Example 1 of the present invention;

[0033] Figure 2 Schematic cross-sectional view of the core board insulation layer and inner circuit layer of Example 1 of the present invention;

[0034] Figure 3 For Figure 2 Corresponding plan diagram;

[0035] Figure 4 This is a schematic structural diagram of Example 2 of the present invention;

[0036] Figure 5 This is a schematic structural diagram of Example 3 of the present invention;

[0037] Figure 6 This is a schematic structural diagram of Example 4 of the present invention;

[0038] Figure 7 This is a schematic structural diagram of Example 5 of the present invention;

[0039] Figure 8 This is a structural diagram of Example 6 of the present invention. DETAILED DESCRIPTION

[0040] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0041] Example 1

[0042] like Figures 1 to 3 FIG. 1 is a preferred embodiment of a circuit board of the present invention.

[0043] The structure of the circuit board of this embodiment includes a circuit layer 10 and an insulation layer 20. The circuit layer 10 prints a coil circuit as an electromagnetic coil to replace the traditional winding coil. The insulation layer 20 can be divided into a core board insulation layer 21, an interlayer insulation layer 22 and an outer insulation layer 23. The circuit layer 10 and the insulation layer 20 are alternately stacked from the inside to the outside starting from the core board insulation layer 21. The specific stacking order of this embodiment is as follows: Figure 1 As shown, the core board insulation layer 21 is located in the middle of the circuit board. An inner circuit layer 11 is provided on the upper and lower surfaces of the core board insulation layer 21. An interlayer insulation layer 22 is provided outside each inner circuit layer 11. An outer circuit layer 12 is provided outside each interlayer insulation layer 22. An outer insulation layer 23 is provided outside each outer circuit layer 12. The core board insulation layer 21 and the interlayer insulation layer 22 are made of epoxy glue, and the outer insulation layer 23 is made of ink.

[0044] In this embodiment, the circuit board has four circuit layers 10. The number and distribution of coils on the same layer can be customized, and the number of coil turns can be determined through exposure and development processes. This allows the OIS coil to be directly embedded in the PCB as a circuit, resulting in a more compact overall structural layout and reduced space occupied by additional components, thus achieving a space-saving effect. Furthermore, the circuit board can be designed with more or fewer circuit layers 10. When the circuit board has only two circuit layers 10, the insulation layer 20 includes only the core insulation layer 21 and the outer insulation layer 23, and does not include the interlayer insulation layer 22. When the circuit board has four or more circuit layers 10, the insulation layer 20 includes a greater number of interlayer insulation layers 22, while the number of core insulation layers 21 and outer insulation layers 23 remains the same.

[0045] In this embodiment, a yoke layer 3 made of a magnetic conductive material is embedded in the insulating layer 20. The embedded high magnetic flux yoke layer 3 can guide the magnetic field, achieving the technical effect of saving space and enhancing driving force, which helps to improve the performance of the OIS motor. The insulating layer 20 between two adjacent circuit layers 10 is provided with a conductive hole 4, and the yoke layer 3 is avoided at the conductive hole 4. Figure 2 As shown, it is ensured that it will not be connected to the conductive circuit of the circuit board, so the circuit resistance will not be increased, and the driving force of the original coil will not be weakened due to the introduction of magnetic conductive material.

[0046] At the same time, the circuit board of this structure is also applicable to other fields. The yoke layer 3 can be made of various high magnetic flux materials. The magnetic conductive material in this embodiment is soft ferrite or hard ferrite. The chemical formula of ferrite is generally MO·Fe2O3, where M is a divalent metal ion (such as Mn 2+ 、Zn 2+ 、Ni 2+ 、Ba 2+ 、Sr 2+ Typical soft ferrites include manganese zinc ferrite (MnZn), with a chemical formula of Mn. 0.5 Zn 0.5 Fe2O4, and nickel-zinc ferrite (NiZn), etc., are suitable for use in:

[0047] a) High-frequency transformer: switching power supply, wireless charger;

[0048] b) Inductor: filtering and energy storage element;

[0049] c) Anti-electromagnetic interference (EMI): magnetic beads, common mode choke;

[0050] d) Microwave devices: isolators, circulators (using the gyromagnetic effect).

[0051] Typical hard ferrites include barium ferrite (BaFe 12 O 19), Strontium ferrite (SrFe 12 O 19 ), etc., suitable for application in:

[0052] a) Motors and generators: automobile starting motors, power tools;

[0053] b) Speakers and sensors: core materials of magnetic circuit system;

[0054] c) Magnetic separation technology: magnetic adsorption in industrial wastewater treatment;

[0055] d) Emerging fields: 5G communication high-frequency components, new energy vehicle motors, and magnetic resonance imaging (MRI) equipment.

[0056] The magnetic conductive material used in this embodiment is a block of soft magnetic ferrite, which forms the first yoke layer 3a. The first yoke layer 3a is embedded in the core board insulation layer 21, and according to the appearance design of the circuit board product, the first yoke layer 3a is pressed as a reinforcement or bonded through the adhesive layer 6 or a combination of the two methods and arranged on the surface of the outer insulation layer 23. During design and production, any one or more first yoke layers 3a can be set at the above-mentioned positions in the circuit board according to actual needs. The more first yoke layers 3a are set and the closer they are to the permanent magnet, the stronger the driving force they provide. The setting of the yoke layer 3 can be flexibly adjusted based on this principle. The first yoke layer 3a actively opens a window to avoid the position during the embedding stage, and its window dividing line 5 can be referred to. Figure 3 As shown, this avoids additional operations during subsequent processing while ensuring accurate alignment of the yoke layers 3.

[0057] When the circuit board is used for a mobile phone OIS motor, the thickness of the yoke layer 3 is in the range of 20-50 μm.

[0058] In addition, the circuit board of this embodiment can also be used for high-power wireless charging. In this case, the thickness of the yoke layer 3 is in the range of 100-200 μm.

[0059] Example 2

[0060] The structure of this embodiment is as follows Figure 4 As shown, the difference between this embodiment and embodiment 1 is that the first yoke layer 3 a is embedded in the core plate insulation layer 21 and the interlayer insulation layer 22 , and is pressed against the surface of the outer insulation layer 23 .

[0061] Example 3

[0062] The structure of this embodiment is as follows Figure 5As shown, the difference between this embodiment and Example 1 is that the magnetic conductive material used in this embodiment is powdered soft magnetic ferrite, which is mixed with the insulating material to form the second yoke layer 3b. The second yoke layer 3b is embedded in the core plate insulating layer 21 and the interlayer insulating layer 22, and is provided on the surface of the outer insulating layer 23.

[0063] Example 4

[0064] The structure of this embodiment is as follows Figure 6 As shown, the difference between this embodiment and embodiment 1 is that the magnetic conductive material used in this embodiment is powdered soft magnetic ferrite, and the powdered ferrite is coated or PVD sprayed in the core plate insulation layer 21, the interlayer insulation layer 22, and the surface of the outer insulation layer 23 to form a third yoke layer 3c.

[0065] Example 5

[0066] The structure of this embodiment is as follows Figure 7 As shown, the difference between this embodiment and embodiment 1 is that the magnetic conductive material used in this embodiment is sheet / film soft magnetic ferrite, and the sheet or film ferrite forms the fourth yoke layer 3d; the fourth yoke layer 3d is pressed and embedded in the core plate insulation layer 21 and the interlayer insulation layer 22, and is arranged on the surface of the outer insulation layer 23.

[0067] Example 6

[0068] The structure of this embodiment is as follows Figure 8 As shown, the difference between this embodiment and embodiment 1 is that the magnetic conductive material used in this embodiment is rod-shaped soft magnetic ferrite, and the rod-shaped ferrite forms the fifth yoke layer 3e; the fifth yoke layer 3e is vertically or horizontally buried in the core plate insulation layer 21 and the interlayer insulation layer 22.

Claims

1. A circuit board, characterized in that: The invention comprises a circuit layer (10) and an insulating layer (20) serving as an electromagnetic coil, wherein the insulating layer (20) comprises a core plate insulating layer (21), the circuit layer (10) and the insulating layer (20) are alternately stacked from the inside to the outside starting from the core plate insulating layer (21), and a yoke layer (3) made of a magnetic conductive material is embedded in the insulating layer (20); a conducting hole (4) is provided in the insulating layer (20) between two adjacent circuit layers (10), and the yoke layer (3) is positioned at the conducting hole (4).

2. The circuit board according to claim 1, wherein: The insulating layer (20) comprises a core insulating layer (21), an interlayer insulating layer (22) and an outer insulating layer (23); a magnetic yoke layer (3) is embedded in the core insulating layer (21) and the interlayer insulating layer (22); and the outer insulating layer (23) is pressed, bonded or coated with the magnetic yoke layer (3).

3. The circuit board according to claim 1, wherein: The magnetic conductive material is soft ferrite or hard ferrite.

4. The circuit board according to claim 1, wherein: The magnetic conductive material is block ferrite, and the block ferrite forms a first magnetic yoke layer (3a); The first magnetic yoke layer (3a) is embedded in the core plate insulation layer (21) and the interlayer insulation layer (22), and is pressed against the surface of the outer insulation layer (23).

5. The circuit board according to claim 1, wherein: The magnetic conductive material is powdered ferrite, which is mixed into the insulating material to form a second magnetic yoke layer (3b); The second yoke layer (3b) is embedded in the core plate insulating layer (21) and the interlayer insulating layer (22), and is arranged on the surface of the outer insulating layer (23).

6. The circuit board according to claim 1, wherein: The magnetic conductive material is powdered ferrite; Powdered ferrite is coated or PVD-sprayed in the core plate insulation layer (21), the interlayer insulation layer (22), and the surface of the outer insulation layer (23) to form a third yoke layer (3c).

7. The circuit board according to claim 1, wherein: The magnetic conductive material is a sheet-shaped or thin-film ferrite, and the sheet-shaped or thin-film ferrite forms a fourth magnetic yoke layer (3d); The fourth yoke layer (3d) is pressed and embedded in the core plate insulation layer (21) and the interlayer insulation layer (22), and is arranged on the surface of the outer insulation layer (23).

8. The circuit board according to claim 1, wherein: The magnetic conductive material is rod-shaped ferrite, and the rod-shaped ferrite forms a fifth magnetic yoke layer (3e); The fifth magnetic yoke layer (3e) is vertically or laterally embedded in the core plate insulating layer (21) and the interlayer insulating layer (22).

9. The circuit board according to claim 1, wherein: The thickness of the yoke layer (3) is in the range of 20-50 μm.

10. The circuit board according to claim 1, wherein: The thickness of the yoke layer (3) is in the range of 100-200 μm.

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