A planar coil

Abstract

The utility model relates to the technical field of coil, concretely provides a kind of plane coil, comprising: insulating substrate, structural glue and coil.Wherein, structural glue is set to one surface of insulating substrate, or, opposite two surfaces;Coil is set to the groove of the side surface of structural glue away from the insulating substrate;Wherein, the depth-width ratio of coil is greater than or equal to 2.5:1.The plane coil provided by the utility model can improve the depth-width ratio of plane coil, further can improve the current carrying capacity, inductance and magnetic flux of coil, provides a disruptive solution for miniaturized electronic system.

Description

Technical Field

[0001] This invention relates to the field of coil technology, and in particular to a planar coil. Background Technology

[0002] With the rapid development of electronic devices, people's demand for thinner and lighter electronic devices is increasing. As a core component for achieving device miniaturization, the performance parameters of planar coils directly determine energy conversion efficiency and overall system performance. The aspect ratio of planar coils is the core factor determining their miniaturization and directly affects electrical performance, thermal performance, and mechanical reliability.

[0003] Traditional planar coils have a low aspect ratio, typically 1:2 to 1:1. This low aspect ratio negatively impacts the current-carrying capacity, inductance, and magnetic flux of the planar coil, preventing it from meeting performance requirements. Furthermore, the turn pitch of planar coils is usually greater than or equal to 50 micrometers. This results in fewer turns per unit area on the same size insulating substrate, leading to lower space utilization and making it difficult to exceed 60% space utilization. The reduction in the effective cross-sectional area of ​​the coil directly weakens the current-carrying capacity per unit area. It is worth noting that when the operating current density exceeds 5 A / mm², the temperature rise of traditional structures exhibits a non-linear accelerating trend, severely limiting high-power-density applications. Utility Model Content

[0004] The present invention provides a planar coil that at least solves the problem of low depth-to-width ratio of planar coils, which affects their current carrying capacity.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] This utility model provides a planar coil, comprising: an insulating substrate; a structural adhesive disposed on one surface of the insulating substrate, or on two opposing surfaces; and a coil disposed in a groove on the surface of the structural adhesive away from the insulating substrate; wherein the depth-to-width ratio of the groove is greater than or equal to 2.5:1.

[0007] Preferably, the spacing between adjacent trenches ranges from 5 μm to 50 μm.

[0008] Preferably, the width of the trench ranges from 1 μm to 30 μm, and the depth of the trench ranges from 5 μm to 80 μm.

[0009] Preferably, the depth-to-width ratio of the trench is greater than or equal to 3:1.

[0010] Preferably, the roughness of the inner wall of the trench is less than or equal to 55 nm.

[0011] Preferably, the coil is a coil obtained by filling the groove with conductive paste.

[0012] Preferably, the surface roughness Ra of the coil is less than 0.18 μm, and the surface roughness Rz of the side surface of the coil is less than 1.5 μm.

[0013] Preferably, the thickness of the insulating substrate is in the range of 10 μm to 60 μm; and the thickness of the structural adhesive is in the range of 10 μm to 80 μm.

[0014] Preferably, when structural adhesive is applied to two opposite surfaces of the insulating substrate, the planar coil includes: a through hole and a guide post located within the through hole; wherein the through hole penetrates the insulating substrate and extends into the structural adhesive located on opposite sides of the insulating substrate, and the guide post is used to connect the coil located on opposite sides of the insulating substrate.

[0015] Preferably, the coil is multi-layered, located on the same side or both sides of the insulating substrate, and the multi-layered coils are interconnected.

[0016] Compared with the prior art, the above-mentioned technical solution of this utility model has the following beneficial effects:

[0017] This invention achieves a breakthrough in three-dimensional spatial performance by optimizing the coil cross-sectional morphology, increasing the aspect ratio to over 2.5:1. The improved design effectively increases the conductor cross-sectional area by over 28%, not only raising the current carrying capacity to the safe threshold of 8A / mm², but also bringing three key technological breakthroughs: First, optimized electromagnetic coupling efficiency increases inductance by 40-60% and magnetic flux by over 30%; second, an innovative single-layer high-density layout simplifies the traditional multi-layer stacked structure to a single layer, reducing the overall volume by 45%; third, the use of double-sided three-dimensional wiring technology increases winding density by 2.3 times under the same substrate area, breaking through the 85% space utilization bottleneck. This structural innovation reduces the material cost per unit device by 22%, providing a disruptive solution for miniaturized electronic systems. Attached Figure Description

[0018] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of this utility model. For those skilled in the art, other embodiments can be obtained based on these drawings without any creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a planar coil according to an embodiment of the present invention;

[0020] Figure 2 This is the utility model Figure 1 Sectional view at point AA;

[0021] Figure 3 This is a schematic diagram of the structure of a planar coil according to another embodiment of the present invention.

[0022] Figure reference numerals:

[0023] 1. Insulating substrate; 2. Structural adhesive; 3. Coil; 4. Through hole. Detailed Implementation

[0024] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0025] like Figure 1 As shown, in order to improve the aspect ratio and current carrying capacity of the planar coil, one embodiment of this invention provides a planar coil, including: an insulating substrate 1, a structural adhesive 2, and a coil 3.

[0026] like Figure 2 As shown, structural adhesive 2 is disposed on one surface of insulating substrate 1, or on two opposing surfaces. Coil 3 is disposed in a groove on the surface of structural adhesive 2 away from insulating substrate 1; wherein the depth-to-width ratio of the groove is greater than or equal to 2.5:1.

[0027] Specifically, insulating substrate 1 refers to the non-conductive material used to support and isolate the conductive coil layer, and can be selected from high-temperature and high-frequency insulating materials such as polyimide or polyimide-imide.

[0028] Structural adhesive 2 is an adhesive applied to the surface of the insulating substrate 1 for imprinting the coil 3. This adhesive can be rapidly cured by ultraviolet (UV) irradiation, which triggers a chemical reaction.

[0029] Furthermore, the structural adhesive 2 can be an epoxy resin material or an acrylic resin material.

[0030] Furthermore, structural adhesive 2 is typically applied to the surface of insulating substrate 1 and then cured by ultraviolet irradiation.

[0031] Structural adhesive 2 can be cured using a UV lamp with a power of 500mW / cm-1000mW / cm for 30 to 60 seconds.

[0032] This utility model provides a planar coil that, through optimizing the coil's cross-sectional morphology, achieves a breakthrough in three-dimensional spatial performance by increasing the aspect ratio to over 2.5:1. Experimental verification shows that this structural improvement effectively increases the conductor cross-sectional area by over 28%, not only raising the current carrying capacity to the safe threshold of 8A / mm², but also simultaneously bringing three key technological breakthroughs:

[0033] Firstly, by optimizing electromagnetic coupling efficiency, the inductance is increased by 40-60%, and the magnetic flux is enhanced by more than 30%.

[0034] Secondly, by utilizing an innovative single-layer high-density layout scheme, the traditional multi-layer stacked structure is simplified into a single layer, reducing the overall volume by up to 45%.

[0035] Third, by adopting double-sided three-dimensional wiring technology, the winding density is increased by 2.3 times under the same substrate area, and the space utilization rate breaks through the technical bottleneck of 85%.

[0036] This structural innovation reduces the material cost per device by 22%, while breaking through the traditional 20μm line spacing limit and achieving stable processing of 10-15μm precision pitch, providing a disruptive solution for miniaturized electronic systems.

[0037] like Figure 3 As shown, this utility model can also coat both sides of the insulating substrate 1 with structural adhesive according to actual needs, and imprint coils on each structural adhesive to become double-sided coils, thereby further increasing the number of coil turns and improving space utilization, which helps to meet the needs of miniaturization and reduce the production cost of planar coils.

[0038] The grooves are preferably formed by pressing a mold onto the surface of the structural adhesive, or they can be formed by etching. The grooves are used to arrange coils and form coils.

[0039] In other words, the depth-to-width ratio of the groove determines the depth-to-width ratio of the coil. By imprinting the groove, the depth-to-width ratio of the groove can reach 2.5:1 or higher, ensuring that the depth-to-width ratio of the planar coil is greater than or equal to 2.5:1.

[0040] The surface of the mold is provided with a subwavelength anti-adhesion structure, forming a convex mold. The subwavelength anti-adhesion structure comprises multiple nanopillars arranged in an array. The array of nanopillars can be a ring array or a rectangular array.

[0041] The punch can be made of materials such as silicone or metal.

[0042] Furthermore, the period of the nanopillar array is preferably 100nm-200nm, and the depth is preferably 20nm-50nm, so as to facilitate the imprinting of the structural adhesive 2 to obtain the groove.

[0043] Further optimization was achieved using a nanopillar array with a period of 200 nm and a depth of 50 nm.

[0044] Furthermore, the arrangement of the grooves is usually based on the shape required by the planar coil, and can be spiral, serpentine, symmetrical differential, or polymorphic.

[0045] Furthermore, the cross-section of the trench can be rectangular or inverted trapezoidal. When the cross-section of the trench is inverted trapezoidal, the width range of the trench refers to the minimum width range of the trapezoid.

[0046] Furthermore, the sidewalls of the groove can be vertical or inclined, and can be straight or curved, depending on the processing requirements and environment to meet different needs.

[0047] The roughness of the inner wall of the trench in this embodiment of the invention is less than or equal to 55 nm, and preferably 50 nm. The trench roughness in this embodiment of the invention is even lower, approaching the flatness of a mirror, thereby significantly reducing the skin effect loss of high-frequency signals.

[0048] Furthermore, the coil is a coil obtained by processing conductive paste, and the coil 3 can be arranged on the structural adhesive 2 in the following manner.

[0049] First, a groove is formed on the side of the structural adhesive 2 away from the insulating substrate 1 and then cured; wherein the depth-to-width ratio of the groove is greater than or equal to 2.5:1; the elastic modulus of the cured groove is greater than or equal to 2 GPa. The groove can be formed by embossing or etching.

[0050] Next, conductive paste is filled into the trench, and the conductive paste is processed to obtain a coil, thus realizing the coil layout.

[0051] The coil processed by the above method, after undergoing low-temperature plasma densification treatment, can achieve a surface roughness Ra < 0.18 μm, preferably Ra < 0.15 μm. The side roughness Rz of the coil is Rz < 1.5 μm, preferably Rz < 1 μm.

[0052] The coil obtained by this embodiment has lower roughness, which can significantly improve the coil's electrical performance, mechanical performance, reliability, and integration process compatibility.

[0053] like Figure 1As shown, the trench is further arranged concentrically with the insulating substrate 1, and a substrate hole is provided at the center of the insulating substrate 1, with the trench surrounding the outside of the substrate hole.

[0054] The planar coil provided by this invention can be applied to wireless charging technology or camera image stabilization technology, and is especially suitable for high-value-added fields such as medical electronics and 5G communication. By placing the planar coil in a camera module, it can provide wireless power supply, electromagnetic shielding, or sensing functions.

[0055] Furthermore, the aspect ratio of coil 3 is preferably 2.5:1, 3:1, or 3.5:1.

[0056] Furthermore, the aspect ratio of the coil is preferably greater than or equal to 3:1.

[0057] Optionally, the spacing between adjacent trenches ranges from 5 μm to 50 μm, preferably 5 μm, 10 μm, 15 μm, 20 μm, 30 μm, 40 μm or 50 μm.

[0058] Furthermore, the spacing between adjacent trenches is preferably in the range of 8 μm to 30 μm, and more preferably 8 μm, 12 μm, 14 μm, 16 μm, 18 μm, 22 μm, 24 μm, 25 μm or 28 μm.

[0059] Preferably, the cross-section of the coil 3 is rectangular. The width of the coil 3 ranges from 8 μm to 25 μm, and the thickness of the coil 3 ranges from 18 μm to 75 μm.

[0060] Furthermore, the width of coil 3 can preferably be 8μm, 10μm, 20μm or 25μm. The thickness of coil 3 can preferably be 18μm, 20μm, 24μm, 30μm, 40μm, 50μm, 60μm, 70μm or 75μm.

[0061] Optionally, the width of coil 3 ranges from 5 μm to 30 μm; the thickness of coil 3 ranges from 10 μm to 80 μm.

[0062] Specifically, the width of coil 3 can be further preferably 5μm, 12μm, 15μm, 20μm, 25μm or 30μm.

[0063] The thickness of coil 3 can be further preferably 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm or 80μm.

[0064] Furthermore, in a preferred but non-limiting embodiment of this invention, the width of the coil is 8 μm to 28 μm, and the depth of the coil is 20 μm to 75 μm.

[0065] The width of the coil is further preferably 8μm, 12μm, 14μm, 18μm, 22μm, 26μm or 28μm. The thickness of the coil is further preferably 25μm, 35μm, 45μm, 55μm, 65μm or 75μm.

[0066] In a preferred but non-limiting embodiment of the present invention, the spacing between two adjacent turns of coil 3 is preferably 8μm to 18μm, and more preferably 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm or 18μm.

[0067] Furthermore, the surface of the insulating substrate 1 is roughened to a roughness of 0.5μm-3.5μm, and more preferably 1μm-3μm, which can enhance the adhesion of the structural adhesive 2.

[0068] More preferably, the thickness of the insulating substrate 1 ranges from 10 μm to 60 μm; and the thickness of the structural adhesive 2 ranges from 10 μm to 80 μm.

[0069] Furthermore, in this embodiment of the invention, the thickness of the insulating substrate 1 is preferably 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm or 60μm.

[0070] The thickness of structural adhesive 2 is preferably 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm or 80μm.

[0071] In a preferred but non-limiting embodiment of the present invention, when the structural adhesive 2 is disposed on two opposite surfaces of the insulating substrate 1, the planar coil further includes: a through hole 4 and a guide post located within the through hole 4.

[0072] The through-hole 4 penetrates the insulating substrate 1 and extends into the structural adhesive 2 located on opposite sides of the insulating substrate 1. The guide post is used to connect the coils located on opposite sides of the insulating substrate.

[0073] Furthermore, a through hole 4 can be obtained by drilling a hole in the planar coil using laser drilling.

[0074] Through hole 4 is a straight circular hole, and the diameter of through hole 4 ranges from 50μm to 100μm.

[0075] Furthermore, the through hole 4 can also penetrate the entire planar coil, including: insulating substrate 1, structural adhesive 2 located on opposite sides of the insulating substrate 1, and coil 3.

[0076] Furthermore, the diameter of the through hole 4 is preferably 50 μm, 80 μm or 100 μm.

[0077] In a particular preferred embodiment, the diameter of the through hole is 50 μm to 100 μm, the aspect ratio of the coil is 3:1, the line width is 10 μm, and the line spacing is 20 μm.

[0078] In this approach, the current-carrying capacity and inductance of the planar coil are further improved.

[0079] In another specific preferred embodiment, the diameter of the through hole is 80 μm, the aspect ratio of the coil is 3:1, the line width is 15 μm, and the line spacing is 30 μm.

[0080] In another specific preferred embodiment, the diameter of the through hole is 120 μm, the aspect ratio of the coil is 3:1, the line width is 10 μm, and the line spacing is 20 μm.

[0081] Furthermore, the coil can be configured with multiple layers, with the multiple coils located on the same side or both sides of the insulating substrate, and the multiple coils being interconnected.

[0082] Specifically, by creating a groove on the structural adhesive, a coil layer can be obtained.

[0083] When multiple coils are located on the same side of an insulating substrate, a multi-layer planar coil can be obtained by setting multiple layers of structural adhesive on the same side of the insulating substrate, creating grooves on each layer of structural adhesive, and connecting the upper and lower coil layers by setting through holes and guide posts. Preferably, the coil can have 4 or 5 layers.

[0084] When multiple coils are placed on both sides of an insulating substrate, structural adhesive is evenly distributed on both sides of the insulating substrate. Grooves are set on each layer of structural adhesive, and the coils of the upper and lower layers are connected by through holes and guide posts to obtain a multi-layer planar coil. The number of coil layers on both sides of the insulating substrate can be adjusted according to the actual situation. For example, one layer of coil can be set on one side of the insulating substrate, and three layers of coil can be set on the other side of the insulating substrate.

[0085] More preferably, the coil has two layers, one on each side of the insulating substrate, and each layer of the coil has 4 turns.

[0086] The planar coil provided by this utility model exhibits multi-dimensional innovative advantages in voice coil motor applications, mainly including the following aspects:

[0087] (1) In terms of power efficiency, since the coil depth-to-width ratio and density of the present invention embodiment are higher, the coil unit can generate stronger electromagnetic driving force, significantly improving the motion control accuracy and response speed of the lens assembly, and providing more agile focusing performance for the high-definition imaging system. The double-density coil layout, combined with the optimized energy transfer path, achieves more efficient electromagnetic conversion efficiency in a limited space.

[0088] (2) In terms of spatial adaptability, this utility model provides a double-sided coil obtained by imprinting coils on two opposing surfaces of structural adhesive, which significantly reduces the three-dimensional dimension of the coil assembly and breaks through the thickness limitations of traditional stacked designs. The precisely arranged micro-circuits enable the utilization of planar space to reach a new level, providing key technical support for the realization of thinner designs in terminal devices.

[0089] (3) In terms of thermal management, the planar coil in this embodiment can effectively improve the uniformity of current distribution. Combined with the innovative heat conduction path design, it can significantly reduce the temperature rise effect under high load. The optimized cross-sectional shape effectively suppresses energy loss in high-frequency applications and ensures the stable performance of the system under complex operating conditions.

[0090] (4) In terms of anti-interference characteristics, the precision-formed coil can optimize the electromagnetic field and effectively reduce signal crosstalk between adjacent lines. The symmetrical electromagnetic structure, combined with the innovative insulation system, significantly improves the uniformity and controllability of the magnetic field distribution, providing a more accurate correction basis for the optical image stabilization system.

[0091] (5) In terms of manufacturing process, this invention, by setting an imprinting groove and pouring conductive paste inside the imprinting groove, forms a more mature continuous coil molding technology, which can break through the limitations of traditional processes and realize the batch precision replication of complex microstructures. The one-piece molding manufacturing process greatly improves product consistency and reduces assembly errors of traditional multi-layer structures. The modular design concept supports rapid customized development, significantly shortens the product iteration cycle, and provides a more competitive solution for the consumer electronics industry.

[0092] The two implementation methods described above better meet the requirements of thick copper and narrow spacing, and while increasing the number of coil turns per unit area, they can ensure good coil performance and obtain good current carrying capacity and inductance.

[0093] The term "embodiment" in this specification refers to a specific feature, structure, or characteristic described in connection with an embodiment that may be included in at least one embodiment of this invention. The appearance of this phrase in various places in the specification does not necessarily imply the same embodiment, nor does it imply independence or alternativeity from other embodiments. The various embodiments in this specification are described in a related manner, with reference to each other for similar or identical parts. In particular, for apparatus, device, and system embodiments, since they are substantially similar to method embodiments, the description is relatively simple, and relevant details are referred to in the description of the method embodiments.

[0094] The above-described embodiments are merely illustrative of several implementations of this invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of protection. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of this invention, and these modifications and improvements all fall within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the appended claims.

Claims

1. A planar coil, characterized in that, include: Insulating substrate; Structural adhesive is applied to one surface of the insulating substrate, or to two opposing surfaces; A coil is disposed in a groove on the surface of the structural adhesive away from the insulating substrate; wherein the depth-to-width ratio of the groove is greater than or equal to 2.5:

1.

2. The planar coil according to claim 1, characterized in that, The spacing between adjacent trenches ranges from 5 μm to 50 μm.

3. The planar coil according to claim 1, characterized in that, The width of the trench ranges from 1 μm to 30 μm, and the depth of the trench ranges from 5 μm to 80 μm.

4. The planar coil according to claim 1, characterized in that, The depth-to-width ratio of the trench is greater than or equal to 3:

1.

5. The planar coil according to claim 1, characterized in that, The roughness of the inner wall of the trench is less than or equal to 55 nm.

6. The planar coil according to claim 1, characterized in that, The coil is obtained by filling the groove with conductive paste.

7. The planar coil according to claim 1, characterized in that, The surface roughness Ra of the coil is less than 0.18 μm, and the surface roughness Rz of the side surface of the coil is less than 1.5 μm.

8. The planar coil according to claim 1, characterized in that, The thickness of the insulating substrate ranges from 10 μm to 60 μm; the thickness of the structural adhesive ranges from 10 μm to 80 μm.

9. The planar coil according to any one of claims 1 to 8, characterized in that, When structural adhesive is applied to two opposite surfaces of the insulating substrate, the planar coil includes: a through hole and a guide post located within the through hole; The through hole penetrates the insulating substrate and extends into the structural adhesive located on opposite sides of the insulating substrate. The guide post is used to connect the coils located on opposite sides of the insulating substrate.

10. The planar coil according to any one of claims 1 to 8, characterized in that, The coil is multi-layered, located on the same side or both sides of the insulating substrate, and the multi-layered coils are interconnected.

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