Inductor row beneficial to AOI detection

Abstract

The inductance bar comprises a magnet, a plurality of external terminals and a plurality of coils wrapped in the magnet, the two wire ends of each coil are connected with the two external terminals respectively, each external terminal extends out of the magnet, the magnet comprises a first surface and a second surface which are connected, and the first surface and the second surface are connected with each other. The external terminal extends out of the magnet through the second surface and extends along the second surface to be attached to the first surface, the magnet is provided with a concave area on the first surface, the joint of the concave area and the second surface protrudes outwards to form an inclined plane, and the external terminal is attached to the inclined plane. On the basis, the bottom of the magnet is equivalently designed to be of a sunken structure, so that the bottom of the side electrode protrudes outwards, the upper part of the side electrode inclines inwards, after SMT mounting is executed, soldering tin is exposed out of the side electrode of each external terminal, soldering tin images can be collected during AOI detection, and whether the welding quality is qualified or not is judged according to the soldering tin images; therefore, the SMT quality can be effectively monitored.

Description

Technical Field

[0001] The present application relates to the technical field of electromagnetic components, and in particular to an inductor bank that is convenient for AOI (Automated Optical Inspection) inspection. Background Art

[0002] With the rapid development of technology, there are more and more electronic devices and their size is getting smaller and smaller. Therefore, more and more electronic components need to be accommodated in the same space. In order to meet this demand, the current industry will make corresponding scientific and reasonable adjustments to the wiring of PCB (Printed Circuit Board), and then put forward relevant requirements for inductor integration, so inductor banks have been developed. The so-called inductor bank refers to multiple coils arranged side by side in a magnetic body. The inductor bank adopts SMT (Surface Mount Technology) to be mounted on a circuit board such as PCB. The high-quality solder joints obtained based on this SMT are the guarantee of the performance and reliability of electronic products. Currently, AOI technology is widely used to check whether there are defects in solder joints. The principle is to use optical technology to obtain images of the detection position and analyze them. To achieve this, the detection position must be unobstructed. However, in the traditional inductor array design, the bend of the external terminal has a rounded transition so that it is bent into two parts. One part serves as a chip electrode for SMT mounting on the circuit board, and the other part serves as a side electrode and is attached to the side of the magnet. The bend of the electrode has a rounded transition, so that a gap is formed between the bend and the surface of the circuit board. When soldering the chip electrode, the solder needs to fill the gap first, which easily causes the solder to not be exposed or to be rarely exposed on the side electrode. When using AOI technology, it is difficult to capture the solder image in the direction parallel to the side electrode, resulting in detection failure, thereby giving a result of unqualified welding quality, affecting the effective monitoring of SMT quality. Utility Model Content

[0003] In view of this, the present application provides an inductor bank that is convenient for AOI inspection, which can improve the problem that the bending parts of the external terminals of the existing inductor bank easily affect the AOI results and the effective monitoring of SMT quality.

[0004] The present application provides an inductor bank that facilitates AOI inspection, comprising a magnet, a plurality of external terminals, and a plurality of coils wrapped within the magnet, wherein two wire ends of each coil are respectively connected to two of the external terminals, and each of the external terminals extends outside the magnet;

[0005] The magnet includes a first surface and a second surface connected to each other, the external terminal extends out of the magnet through the second surface, and extends along the second surface to be in contact with the first surface, the magnet is provided with a recessed area on the first surface, the junction of the recessed area and the second surface is convex to form an inclined surface, and the external terminal is in contact with the inclined surface.

[0006] Optionally, the second surface is the bottom surface of the magnet, and the first surface includes a first side surface and a second side surface of the magnet that are oppositely arranged.

[0007] Optionally, at least a portion of the external terminal that is in contact with the inclined surface protrudes from the first surface, or is flush with the first surface.

[0008] Optionally, the angle between the inclined surface and the second surface is α, and satisfies: 40°≤α<90°.

[0009] Optionally, the external terminal includes an end portion and a root portion that are arranged opposite to each other along its own extension direction, the root portion is adjacent to the second surface, and the end portion is located in the recessed area and is attached to the inclined surface.

[0010] Optionally, the external terminal includes an end portion and a root portion that are oppositely arranged along its own extension direction, the root portion is adjacent to the second surface, and the end portion is located in the recessed area;

[0011] The end portion is not in contact with the inclined surface and the maximum distance between the two is d1, the minimum distance between the root portion and the bottom of the recessed area is d2, and d1 <d2。

[0012] Optionally, the end of the external terminal extends to the bottom of the recessed area.

[0013] Optionally, the external terminal affixed to the inclined surface is higher than the lowest point of the coil.

[0014] Optionally, two wire ends of each coil extend toward the second surface.

[0015] Optionally, the inductor bank further includes at least one electromagnetic partition, and a single electromagnetic partition is disposed between any two adjacent coils to isolate electromagnetic interference between the two adjacent coils.

[0016] As described above, in the inductor array of the present application, the portion of the external terminal that is bonded to the inclined surface can be used as a side electrode, and the portion of the external terminal corresponding to the second surface can be used as a patch electrode. The magnet is provided with a recessed area in the portion corresponding to the side electrode and the patch electrode, which is equivalent to adopting an inward-recessed structural design, which can make the bottom of the side electrode convex and the upper part inward-inclined. Therefore, when the patch electrode is welded to the circuit board to perform SMT mounting, the solder used for welding will produce a tin creep phenomenon, that is, the solder will overflow toward the side electrode and adhere to the outer surface of the side electrode. Therefore, the finally solidified solder will be exposed to the side electrodes of each external terminal. When using AOI technology, the solder image can be collected in the vertical direction, and this can be used to judge whether the welding quality is qualified, thereby realizing effective monitoring of SMT quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 and Figure 2 3D diagrams of the structure of a highly integrated inductor bank according to an embodiment of the present application from two perspectives;

[0018] Figure 3 yes Figure 1 A cross-sectional view of the highly integrated inductor array along the AA direction is shown;

[0019] Figure 4 yes Figure 3 The structure of the area selected by the dashed line is shown as an enlarged view;

[0020] Figure 5 yes Figure 1 The relative structural diagram of the coil and electromagnetic partition of the highly integrated inductor array is shown.

[0021] First direction x, second direction y, third direction z;

[0022] Magnet 1, first surface 10a, second surface 10b;

[0023] First outer surface 101, second outer surface 102, third outer surface 103, fourth outer surface 104, fifth outer surface 105, sixth outer surface 106, recessed area 11, inclined surface 111;

[0024] Coil 2, accommodating area 20;

[0025] External terminal 3, patch electrode 31, side electrode 32, root 321, end 322;

[0026] Electromagnetic partition 4. DETAILED DESCRIPTION

[0027] In the inductor array of the present application, the portion of the external terminal that is bonded to the inclined surface can be used as a side electrode, and the portion of the external terminal corresponding to the second surface can be used as a patch electrode. The magnet is provided with a recessed area in the portion corresponding to the side electrode and the patch electrode, which is equivalent to adopting a recessed structural design. The bottom of the side electrode is convex and the upper part is inwardly inclined. After SMT mounting is performed on the patch electrode, the solder will be exposed to the side electrodes of each external terminal, which is conducive to AOI detection.

[0028] The specific forms of the parameters such as the shape, quantity, and size of the magnets, coils, and external terminals can be determined according to the actual application and the required adaptability of the configuration, and this application does not limit them.

[0029] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly described below in conjunction with specific embodiments and corresponding drawings. Obviously, the embodiments described below are only some of the embodiments of this application, not all of them. Unless there is a conflict, the following embodiments and their technical features can be combined with each other and also belong to the technical solutions of this application.

[0030] Please also refer to Figures 1 to 5 An inductor bank (hereinafter referred to as "inductor bank") facilitating AOI inspection according to one embodiment of the present application includes a magnet 1, at least two coils 2, at least two external terminals 3, and at least one electromagnetic barrier 4. The figure illustrates and describes four coils 2, eight external terminals 3, and three electromagnetic barriers 4 as an example, but it should be understood that this does not limit the scope of protection.

[0031] For ease of description and understanding, in conjunction with the placement orientation shown in the figure, the length direction of the inductor array will be referred to as the first direction x, the height direction as the second direction y, and the width direction as the third direction z. The first direction x, the second direction y, and the third direction z are perpendicular to each other and can be regarded as the three coordinate axes of a three-dimensional rectangular coordinate system. It should be understood that the term "perpendicular" throughout this application does not require that the angle between the two must be 90°, but rather allows for a deviation of, for example, ±10°. That is, the term "perpendicular" can be understood as meaning that the angle between any two directions is 80° to 100°. Similarly, the term "parallel" throughout this application does not require that the angle between the two must be 0° or 180°, but rather allows for a deviation of, for example, ±10°. That is, the term "parallel" can be understood as meaning that the angle between any two directions is 0° to 10° or 170° to 190°.

[0032] All coils 2 are arranged in sequence along the first direction x. The structures of the coils 2 may be completely the same or different. This article takes the same coils 2 as an example for demonstration and description.

[0033] In one example, the coil 2 can be formed by winding a wire (such as a copper enameled wire, or a strip conductor, or a long sheet conductor) around a accommodating area 20 in circles. The accommodating area 20 can be regarded as a cavity where the inner turn of the coil 2 is located, and can be the area to which the axis extends during winding. The thickness of each coil 2 (i.e., the length along the second direction y, also known as the "height") can be defined by the diameter of the wire (or the width of the conductor) and the number of turns. For the coil 2 in a standing state, the two ends of the wire or conductor serve as the two wire ends of the coil 2 that are arranged opposite to each other along the third direction z. The two wire ends are both located below the coil 2 and are arranged opposite to each other on the left and right.

[0034] The two external terminals 3 are connected to two opposite wire ends of the coil 2 respectively.

[0035] A single electromagnetic partition 4 is provided between any two adjacent coils 2 to isolate the electromagnetic interference between the two adjacent coils 2. The material of the electromagnetic partition 4 is adaptable and is not limited by this application. Figure 5 The circle shown can of course also be a polygon of other shapes to adapt to the coil 2 with a circular cross section as a whole.

[0036] The minimum distance between two adjacent coils 2 (i.e., along the first direction x) can be slightly larger than the thickness of a single electromagnetic partition 4, that is, the opposite sides of each electromagnetic partition 4 are not in contact with the two adjacent coils 2, but are provided with a "magnetic wall" formed by magnetic material. Here, while the opposite sides of each electromagnetic partition 4 are tightly fitted with the two adjacent coils 2, the magnetic material of the magnet 1 also extends between the electromagnetic partition 4 and the adjacent coil 2, thereby forming a closed magnetic circuit for a single inductor.

[0037] All electromagnetic baffles 4 are arranged in parallel, and the first direction x is perpendicular to these electromagnetic baffles 4. Along the first direction x, the orthographic projections of the accommodating areas 20 of these coils 2 can overlap. In this way, all coils 2 and all electromagnetic baffles 4 of the present application can be arranged more closely.

[0038] The magnet 1 is an integrally formed structural member, for example, formed by injection molding and curing of an adaptable flowable magnetic material. All coils 2 and all electromagnetic partitions 4 are enclosed within the magnet 1, and the magnet 1 extends into and fills the accommodation area 20 of each coil 2. The magnet 1 also extends into the gaps between the wires (or conductors) of each coil 2, thereby ensuring close contact between the magnet 1 and each coil 2, completely enclosing and enclosing each coil 2.

[0039] Each external terminal 3 extends beyond the magnet 1. Specifically, the magnet 1 includes a first surface 10a and a second surface 10b connected thereto. For any external terminal 3, the external terminal 3 extends beyond the magnet 1 via the second surface 10b and extends along the second surface 10b until it is aligned with the first surface 10a. The magnet 1 is provided with a recessed area 11 on the first surface 10a. The junction of the recessed area 11 and the second surface 10b is convex to form an inclined surface 111, and the external terminal 3 is aligned toward the inclined surface 111.

[0040] It should be noted that the first surface 10a and the second surface 10b refer to two connected surfaces of the magnet 1. The specific forms of the first surface 10a and the second surface 10b are adaptable to the specific shape of the magnet 1 in actual scenarios.

[0041] by Figure 1 and Figure 2 Taking the structural shape shown as an example, the magnet 1 includes six outer surfaces, namely: a first outer surface 101, a second outer surface 102, a third outer surface 103 and a fourth outer surface 104 connected end to end, and a fifth outer surface 105 and a sixth outer surface 106 arranged opposite to each other. Among them, the second outer surface 102 and the fourth outer surface 104 are arranged opposite to each other along the second direction y, the first outer surface 101 and the third outer surface 103 are arranged opposite to each other along the third direction z, the fifth outer surface 105 and the sixth outer surface 106 are arranged opposite to each other along the first direction x, the first outer surface 101, the second outer surface 102, the third outer surface 103 and the fourth outer surface 104 are connected between the fifth outer surface 105 and the sixth outer surface 106, that is, the fourth outer surface 104 can be regarded as the upper surface of the magnet 1, the second outer surface 102 can be regarded as the lower surface of the magnet 1, the first outer surface 101 can be regarded as the left side of the magnet 1, or called "first side 101", the third outer surface 103 can be regarded as the right side of the magnet 1, or called "second side 103", the fifth outer surface 105 can be regarded as the front surface of the magnet 1, and the sixth outer surface 106 can be regarded as the back surface of the magnet 1.

[0042] In this example, the first surface 10a includes a first outer surface 101 and a third outer surface 103, i.e., the first side surface 101 and the second side surface 103 of the magnet 1 which are arranged opposite to each other; correspondingly, the second surface 10b is the second outer surface 102, i.e., the bottom surface of the magnet 1.

[0043] The two wire ends of each coil 2 can extend toward the second outer surface 102. For the two external terminals 3 connected to the same coil 2, one external terminal 3 extends out of the magnet 1 through the second outer surface 102 and extends through the second outer surface 102 to mate with the first outer surface 101, and the other external terminal 3 extends out of the magnet 1 through the second outer surface 102 and extends through the second outer surface 102 to mate with the third outer surface 103. Figures 1 to 5 In the illustrated scenario, the two external terminals 3 extend out of the magnet 1 and then fit with the second outer surface 102 , and extend to the first outer surface 101 and then fit with the first outer surface 101 .

[0044] Here, the portion of the single external terminal 3 located on the second outer surface 102 can be used as a patch electrode 31 for SMT mounting on a circuit board such as a PCB, and the portion of the single external terminal 3 located on the first outer surface 101 (or on the third outer surface 103) can be used as a side electrode 32.

[0045] The magnet 1 may be provided with a recessed area 11 on the first outer surface 101 and the third outer surface 103. The junction of the recessed area 11 and the second outer surface 102 is convex to form an inclined surface 111, and the external terminal 3 is attached to the inclined surface 111. It can be seen that the bottom of the magnet 1 is equivalent to a recessed structural design. Please continue to refer to Figures 1 to 4 As shown, the bottom of the side electrode 32 can be made to bulge outward and the upper part inward. Therefore, when the patch electrode 31 is soldered to the circuit board to perform SMT mounting, the solder used for soldering will produce a tin creep phenomenon, that is, the solder will overflow toward the side electrode 32 and adhere to the outer surface of the side electrode 32. Therefore, the solder after final solidification will be exposed to the side electrode 32 of each external terminal. When using AOI technology, the solder image can be collected along the vertical direction y, and this can be used to determine whether the welding quality is qualified, thereby realizing effective monitoring of SMT quality.

[0046] exist Figures 1 to 4 In the example shown, for any external terminal 3, the external terminal 3 includes a root portion 321 and an end portion 322 that are arranged opposite each other along the external terminal's extension direction. This can be considered as a side electrode 32 comprising the root portion 321 and the end portion 322. The root portion 321 is adjacent to the second surface 10b and connected to the patch electrode 31, while the end portion 322 is located within the recessed area 11 and abuts against the inclined surface 111. The end portion 322 of the external terminal 3 can extend to the bottom of the recessed area 11, where the bottom of the recessed area 11 refers to the location where the recessed area 11 has its greatest depth.

[0047] In other examples, the end portion 322 may not be in contact with the inclined surface 111, and the maximum distance between the two (along the first direction x) is d1. The minimum distance between the root portion 321 and the bottommost part of the recessed area 11 (along the first direction x) is d2, and d1 < d2. That is to say, the end portion 322 may protrude outward, but after protruding outward, it does not exceed the corresponding root portion 321. In this case, when using the AOI technology, the solder image of the root portion 321 can be collected at least along the vertical direction y.

[0048] In one example, at least a part of the external connection terminal 3 that is in contact with the inclined surface 111, that is, the side electrode 32, protrudes outward from the first surface 10a. That is, at least a part of the side electrode 32 of the left external connection terminal 3 protrudes outward from the first outer surface 101 of the magnet 1, and at least a part of the side electrode 32 of the right external connection terminal 3 protrudes outward from the third outer surface 103 of the magnet 1. In other examples, for any external connection terminal 3, at least a part of its side electrode may be flush with the first surface 10a.

[0049] Optionally, the included angle between the inclined surface 111 and the second surface 10b is α, and it satisfies: 40° ≤ α < 90°. That is, this included angle α is an acute angle. The acute angle design is beneficial to the contact between the side electrode 32 and the inclined surface 111, and is also beneficial to collecting the solder image during AOI detection.

[0050] In addition, in the second direction y, the side electrodes 32 of each external connection terminal 3 can be higher than the lowest part of the coil 2. That is, the end portion 322 of the side electrode 32 can be higher than the lowest part of the coil X, so that the side electrodes 32 of each external connection terminal 3 have sufficient length, which is beneficial to improving the contact effect between the side electrode 32 and the corresponding inclined surface 111, and avoiding the side electrode 32 from warping outward and blocking the solder image in the opposite direction of the second direction y.

[0051] In the inductor row of the present application, each coil 2, the adjacent electromagnetic partition 4, the two connected external connection terminals 3, and the magnet 1 used for wrapping form each inductor. Compared with the existing inductor row, the present application uses the integrally formed magnet 1 to replace the magnet for each coil 2, and there is no need to set a separate magnetic housing for each coil 2. In this way, the inductor row has a high integration efficiency, can reduce the volume of the entire inductor row, and at the same time, the magnet 1 is in close contact with each coil 2, and the heat conduction between the coil 2 and the magnet 1 is good. The heat generated by the coil 2 can be quickly dissipated through the surface of the magnet 1, and the heat dissipation is good. In addition, each coil 2 is completely wrapped and enclosed by the magnet 1, so that the magnetic leakage of the entire inductor row can be greatly reduced.

[0052] In one example, the cross-sectional area of ​​the magnet 1 perpendicular to the first direction x (i.e., the area of ​​the yz cross section) is S0, the orthographic projection area of ​​the electromagnetic partition 4 along the first direction x is S1, and the coil area of ​​the coil 2 (i.e., the area of ​​the yz cross section) is S2, and the following conditions are satisfied: 0.5*S2≤S1≤0.9*S0. In this way, the electromagnetic partition 4 can not only effectively isolate electromagnetic interference between two adjacent coils 2, but also reduce the cross-sectional area of ​​the magnet 1, further improving integration efficiency.

[0053] In one example, the magnetic permeability of the electromagnetic partition 4 is μ1, the magnetic permeability of the magnet 1 is μ0, and the following condition is satisfied: μ1<0.5*μ0, so that the electromagnetic partition 4 has a good electromagnetic isolation effect.

[0054] The above descriptions are only some embodiments of the present application and do not limit the patent scope of the present application. For ordinary technicians in this field, any equivalent structural changes made using the contents of this specification and drawings are also included in the patent protection scope of the present application.

[0055] In the description of the embodiments of the present application, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. to indicate the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the technical solutions of the corresponding embodiments, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and should not be understood as a limitation on the present application.

[0056] Although the terms "first," "second," and the like are used herein to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. In addition, the singular forms "a," "an," and "the" are intended to include the plural forms as well. The terms "or" and "and / or" are to be interpreted as inclusive, meaning any one or any combination. Exceptions to this definition occur only when a combination of elements, functions, steps, or operations is inherently mutually exclusive in some manner.

Claims

1. An inductor bank that facilitates AOI inspection, comprising a magnet, a plurality of external terminals, and a plurality of coils enclosed within the magnet, wherein two wire ends of each coil are connected to two of the external terminals, respectively, and each external terminal extends beyond the magnet, characterized in that: The magnet includes a first surface and a second surface connected to each other, the external terminal extends out of the magnet through the second surface, and extends along the second surface to be in contact with the first surface, the magnet is provided with a recessed area on the first surface, the junction of the recessed area and the second surface is convex to form an inclined surface, and the external terminal is in contact with the inclined surface.

2. The inductor bank according to claim 1, characterized in that: The second surface is the bottom surface of the magnet, and the first surface includes a first side surface and a second side surface of the magnet that are oppositely disposed.

3. The inductor bank according to claim 1, characterized in that: At least a portion of the external connection terminal facing the inclined surface protrudes from the first surface or is flush with the first surface.

4. The inductor bank according to any one of claims 1 to 3, characterized in that: The included angle between the inclined surface and the second surface is α, and satisfies: 40°≤α<90°.

5. The inductor bank according to claim 4, characterized in that: The external terminal includes an end portion and a root portion which are arranged opposite to each other along its extension direction. The root portion is adjacent to the second surface, and the end portion is located in the recessed area and is attached to the inclined surface.

6. The inductor bank according to claim 4, characterized in that: The external terminal includes an end portion and a root portion that are oppositely arranged along its own extension direction, the root portion is adjacent to the second surface, and the end portion is located in the recessed area; The end portion is not in contact with the inclined surface and the maximum distance between the two is d1, the minimum distance between the root portion and the bottom of the recessed area is d2, and d1 <d2。 7. The inductor bank according to claim 5 or 6, characterized in that: The end of the external terminal extends to the bottom of the recessed area.

8. The inductor bank according to claim 1, characterized in that: The external terminal attached to the inclined surface is higher than the lowest point of the coil.

9. The inductor bank according to claim 1, characterized in that: Two wire ends of each coil extend toward the second surface.

10. The inductor bank according to claim 1, characterized in that: The inductor bank further includes at least one electromagnetic partition, wherein a single electromagnetic partition is disposed between any two adjacent coils to isolate electromagnetic interference between the two adjacent coils.

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