Inductor
By optimizing the coverage area ratio and structure of the external electrode, the problem of excessively large area between the external and internal electrodes was solved, achieving high-performance inductor at high frequencies.
Patent Information
- Application Number
- CN202422909697.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-27
- Publication Date
- 2025-11-14
- Estimated Expiration
- 2034-11-27
AI Technical Summary
The large area between the external and internal electrodes of existing multilayer chip inductors leads to increased parasitic capacitance at high frequencies, affecting the product's Q value and SRF value.
The design incorporates an uneven coverage area for the outer electrodes, with the first coverage area being smaller than the second coverage area. This reduces the area directly opposite the outer electrodes to the inner coil of the main body. By adjusting the coverage ratio and area proportion of the outer electrodes, the electrode structure is optimized to reduce the generation of parasitic capacitance.
This effectively reduces the generation of parasitic capacitance at high frequencies, ensuring that the Q value and SRF value of the product do not decrease, and improving the high-frequency characteristics of the inductor.
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Figure CN223552372U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of electronic components technology, and in particular to an inductor. Background Technology
[0002] The fabrication method of multilayer chip inductors mainly includes the following steps: printing coils on ferrite or ceramic bodies; stacking multiple coil layers; pressing and sealing the coil layers; sintering the stack of coil layers; and finally coating the two ends of the sintered stack with external electrodes to form a multilayer chip inductor.
[0003] In related technologies, the external electrodes are coated on the end face of the inductor, as well as the side and main surfaces connected to it. Typically, the coating width of the external electrodes on the side and main surfaces is consistent and generally quite wide. Therefore, the area between the external and internal electrodes in these technologies is relatively large, which can affect the high-frequency characteristics of the product. For example, in multilayer inductors, parasitic capacitance increases at high frequencies, leading to a relative decrease in Q value (quality factor) and SRF value (self-resonant frequency). Summary of the Invention
[0004] To solve at least one of the above-mentioned technical problems, this application provides an inductor, and the technical solution adopted is as follows.
[0005] This application provides an inductor, comprising: a body having a coil formed therein, the coil extending along the height direction of the body, the body having a first main surface and a second main surface disposed opposite to each other along its height direction; and external electrodes having the external electrodes respectively disposed at both ends of the body along its length direction, the external electrodes being connected to the coil, the external electrodes covering a portion of the first main surface to form a first covering area, the external electrodes covering a portion of the second main surface to form a second covering area, the first covering area of the external electrodes being smaller than the second covering area.
[0006] In some embodiments of this application, the length of the first covering area is c1, the length of the second covering area is c2, and the c1 / c2 ratio of the external electrode is 50%~100%.
[0007] In some embodiments of this application, the width of the first coverage area is a, the width of the second coverage area is b, and the width b of the external electrode is greater than or equal to a.
[0008] In some embodiments of this application, the a / b ratio of the external electrode is 5% to 90%.
[0009] In some embodiments of this application, the length of the first main surface is d, and the a / d ratio is 0.5% to 34%.
[0010] In some embodiments of this application, the a / d ratio is 0.5% to 10%.
[0011] In some embodiments of this application, the body has a first side surface and a second side surface disposed opposite to each other along its width direction, the outer electrode covers a portion of the first side surface to form a third covering area, the outer electrode covers a portion of the second side surface to form a fourth covering area, and the second covering area is at least greater than the smaller of the third covering area and the fourth covering area.
[0012] In some embodiments of this application, the first coverage area is greater than or equal to the third coverage area, and the first coverage area is greater than or equal to the fourth coverage area.
[0013] In some embodiments of this application, the width of the third coverage area and the width of the fourth coverage area are both equal to the width of the first coverage area.
[0014] In some embodiments of this application, the main body is provided with a plurality of stacked conductor patterns, an insulating layer is provided between each pair of adjacent conductor patterns, and a conductor through hole is formed on the insulating layer. The plurality of conductor patterns are connected through the conductor through hole to form the coil.
[0015] The embodiments of this application have at least the following beneficial effects: the coil extends along the height direction of the body, and the first main surface and the second main surface are disposed opposite to each other along the height direction of the body, so the first main surface and the second main surface are respectively disposed opposite to the coil. The first covering area of the external electrode is smaller than the second covering area, thereby relatively reducing the area of the external electrode facing the coil in the body, reducing the generation of parasitic capacitance at high frequencies, and ensuring that the Q value (quality factor) and SRF value (self-resonant frequency) of the product do not decrease. Attached Figure Description
[0016] The aspects and advantages described and / or added to the embodiments of this application will become apparent and readily understood in conjunction with the following drawings. It should be noted that the embodiments illustrated in the following drawings are exemplary and are used only to explain this application, and should not be construed as limiting this application.
[0017] Figure 1 This is a schematic diagram of the structure of an inductor provided in an embodiment of this application;
[0018] Figure 2 This is another structural schematic diagram of the inductor provided in an embodiment of this application;
[0019] Figure 3 A schematic diagram of the structure of the main body when the first and second main surfaces are protruding, as provided in an embodiment of this application;
[0020] Figure 4Another structural schematic diagram of the main body provided in the embodiments of this application;
[0021] Figure 5 Another structural schematic diagram of the main body provided in the embodiments of this application;
[0022] Figure 6 A cross-sectional view of the main body provided in the embodiments of this application;
[0023] Figure 7 A schematic diagram of the structure of the main body when the first and second side surfaces are protruding, as provided in an embodiment of this application;
[0024] Figure 8 A schematic diagram of the structure of the main body when the first end surface and the second end surface are protruding, as provided in an embodiment of this application;
[0025] Figure 9 This is a schematic diagram of the structure of an electrode raw material tape with a conductor pattern provided in an embodiment of this application;
[0026] Figure 10 Another schematic diagram of an electrode raw material tape with a conductor pattern provided in an embodiment of this application;
[0027] Figure 11 A cross-sectional view of an inductor provided in an embodiment of this application;
[0028] Figure 12 for Figure 11 Enlarged view of section E in the middle.
[0029] Reference numerals: Body 100, First main surface 110, Second main surface 120, Bottom electrode 121, First side surface 130, Second side surface 140, First end surface 150, Second end surface 160, Electrode raw material tape 170, Conductor pattern 171, Lead-in electrode 172, Lead-out electrode 173, Outer electrode 200, First covering area 211, Second covering area 212, Third covering area 213, Outer electrode body 221, Nickel layer 222, Tin layer 223. Detailed Implementation
[0030] The following is combined Figures 1 to 12 The embodiments of this application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.
[0031] In the description of this application, it should be understood that the use of terms such as "center," "middle," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" to indicate orientation or positional relationships is based on the orientation or positional relationships shown in the accompanying drawings and is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.
[0032] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0033] In this embodiment, the X-axis direction in the accompanying drawings is the length direction of the main body 100; the Y-axis direction is the width direction of the main body 100; and the Z-axis direction is the height direction of the main body 100.
[0034] See Figure 1 This application provides an inductor that can reduce the area of the external electrode facing the coil in the body 100, reduce the generation of parasitic capacitance at high frequencies, and ensure that the Q value (quality factor) and SRF value (self-resonant frequency) of the product are not reduced.
[0035] For example, the inductor includes a body 100 and an external electrode, and a coil is formed within the body 100, extending along the height direction of the body 100. See [link to relevant documentation]. Figure 2 and Figure 3 The main body 100 has a first main surface 110 and a second main surface 120 disposed opposite to each other along its height direction; external electrodes are respectively disposed at both ends of the main body 100 along its length direction, the external electrodes are connected to the coil, the external electrodes cover the first main surface 110 to form a first covering area 211, the external electrodes cover the second main surface 120 to form a second covering area 212, and the first covering area 211 of the external electrodes is smaller than the second covering area 212.
[0036] It is understood that the coil extends along the height direction of the main body 100, and the first main surface 110 and the second main surface 120 are arranged opposite each other along the height direction of the main body 100. Therefore, the first main surface 110 and the second main surface 120 are respectively arranged opposite to the coil. The first covering area 211 of the external electrode is smaller than the second covering area 212, which can relatively reduce the area of the external electrode facing the coil in the main body 100, reduce the generation of parasitic capacitance at high frequencies, and ensure that the Q value (quality factor) and SRF value (self-resonant frequency) of the product do not decrease.
[0037] For example, the main body 100 is rectangular, the upper surface of the main body 100 is the first main surface 110 of the main body 100, and the lower surface of the main body 100 is the second main surface 120 of the main body 100. Optionally, a bottom electrode 121 is provided on the second main surface 120 (see...). Figure 11 and Figure 12 ).
[0038] Alternatively, in some embodiments, see Figure 4 and Figure 5 The length of the first covering area 211 is c1, the length of the second covering area 212 is c2, and the c1 / c2 ratio of the external electrode is 50%~100%.
[0039] Alternatively, in some embodiments, see Figure 4 and Figure 5 The width of the first coverage area 211 is a, the width of the second coverage area 212 is b, and the width of the external electrode is greater than or equal to a.
[0040] Optionally, in some embodiments, the a / b ratio of the external electrode is 5% to 90%.
[0041] Optionally, the a / b ratio of the external electrode is 50% to 70%.
[0042] It should be noted that if the a / b ratio is less than 5%, the solderability and bonding strength of the end-coated outer electrode will be affected, and it is prone to deterioration; if the a / b ratio is greater than 90%, the area directly opposite the end-coated outer electrode and the internal coil will increase, and the electrical performance will deteriorate.
[0043] Alternatively, in some embodiments, see Figure 5 and Figure 6 The length of the first main surface 110 is d, and the a / d ratio is 0.5%~34%.
[0044] Understandably, an a / d ratio of 0.5% to 34% can ensure weldability while reducing the area of the external electrode facing the internal coil, thereby reducing the generation of parasitic capacitance at high frequencies and reducing the impact on Q value and SRF value.
[0045] Optionally, the a / d ratio can be 0.5% to 10%.
[0046] Alternatively, in some embodiments, see Figure 2 and Figure 7 The main body 100 has a first side surface 130 and a second side surface 140 disposed opposite to each other along its width direction. The outer electrode covers the first side surface 130 to form a third covering area 213, and the outer electrode covers the second side surface 140 to form a fourth covering area (not shown in the figure). The second covering area 212 is at least larger than the smaller of the third covering area 213 and the fourth covering area.
[0047] Optionally, in some embodiments, the first coverage area 211 is greater than or equal to the third coverage area 213, and the first coverage area 211 is greater than or equal to the fourth coverage area.
[0048] In other words, the first coverage area 211 is A1, the third coverage area 213 is A3, and the ratio of A3 / A1 is 0~100%; the fourth coverage area is A4, and the ratio of A4 / A1 is 0~100%.
[0049] Since the second coverage area 212 is larger than the first coverage area 211, the second coverage area 212 is larger than the third coverage area 213, and also larger than the fourth coverage area.
[0050] Optionally, in some embodiments, the width of the third coverage area 213 and the width of the fourth coverage area are both equal to the width of the first coverage area 211.
[0051] Optionally, see Figure 2 and Figure 8 The main body 100 has a first end surface 150 and a second end surface 160 disposed opposite to each other along its length direction, and two external electrodes at both ends of the main body 100 respectively cover the entire first end surface 150 and the entire second end surface 160.
[0052] It is understood that in the embodiments of this application, welding can be performed on the second main surface 120, the first end surface 150 and the second end surface 160, which can reduce the area of the external electrode while ensuring weldability.
[0053] Optionally, in some embodiments, the inductor is a multilayer chip inductor.
[0054] For example, the main body 100 is provided with a plurality of stacked conductor patterns 171, an insulating layer is provided between each pair of adjacent conductor patterns 171, and conductor through holes are provided on the insulating layer. The plurality of conductor patterns 171 are connected through the conductor through holes to form a coil.
[0055] Optionally, see Figure 6Multiple stacked conductor patterns 171 are arranged sequentially along the height direction of the main body 100. The conductor pattern 171 at the top layer is the lead-in electrode 172, and the conductor pattern 171 at the bottom layer is the lead-out electrode 173. The lead-in electrode 172 and the lead-out electrode 173 are respectively used to connect with the external electrodes at both ends of the main body 100, so that the two external electrodes are respectively connected to the coil.
[0056] Optionally, see Figure 9 and Figure 10 Conductor patterns 171 are printed on the surface of electrode raw material tape 170, and each pair of adjacent conductor patterns 171 can form a double-rounded loop. Optionally, Figure 9 and Figure 10 The conductor pattern 171 is stacked alternately to form a coil.
[0057] Of course, the conductor pattern 171 can also be other shapes, and no specific restrictions are imposed here.
[0058] Optionally, see Figure 11 and Figure 12 The external electrode includes an external electrode body 221 and a nickel layer 222 and a tin layer 223 sequentially covering the outer layer of the external electrode body 221. Optionally, the external electrode body 221 is made of a sintered metal body. Optionally, the sintered metal body may include a silver component, that is, the sintered metal body may be a silver sintered body, and a nickel layer 222 and a tin layer 223 are sequentially plated on the sintered metal body; Optionally, the areas of the nickel layer 222 and the tin layer 223 on the second main surface 120 are both the same as the area of the bottom electrode 121.
[0059] Alternatively, the conductor pattern 171 may also be made of a sintered metal body. Optionally, the sintered metal body may include a silver component.
[0060] Optionally, the insulating layer may include a ferrite sintered body or a ceramic sintered body. Optionally, a SiO2-Al2O3 based ceramic sintered body may be used.
[0061] This application also provides a method for manufacturing a multilayer chip inductor, including the following steps.
[0062] Step S100: Create a stacked body.
[0063] A multilayer electrode raw material tape 170 is stacked to obtain a laminate; wherein, a conductor pattern 171 is printed on the surface of each layer of electrode raw material tape 170, the conductor pattern 171 on the top layer of electrode raw material tape 170 is made into an input electrode 172, and the conductor pattern 171 on the bottom layer of electrode raw material tape 170 is made into an output electrode 173.
[0064] A bottom electrode 121 is printed on the electrode raw material tape 170. The electrode raw material tape 170 with the bottom electrode 121 printed is stacked on the bottom of the outermost layer of the stack to form the second main surface 120 of the main body 100. The bottom electrode 121 forms the bottom electrode 121 of the second main surface 120, thereby forming a complete green stack.
[0065] Through holes are made in the electrode raw material tape 170 between the introduced electrode 172 and each conductor pattern 171, and electrode slurry is filled into the through holes so that the introduced electrode 172 and the multiple conductor patterns 171 inside are interconnected.
[0066] Step S200: Sintering the laminate.
[0067] The laminate obtained in step S100 is sintered to obtain the main body 100. The sintering temperature range is 850℃~900℃. The sintering atmosphere is air, and the sintering time ranges from 30min to 60min.
[0068] Step S300: Fabricate the external electrode.
[0069] External electrode bodies 221 are coated at both ends of the main body 100 using an end-coating process and then sintered. Optionally, the external electrode bodies 221 can be silver. Subsequently, a nickel layer 222 and a tin layer 223 are sequentially applied to the outer layer of the external electrode bodies 221 to form a complete external electrode, thereby obtaining a multilayer chip inductor.
[0070] In other words, the external electrode includes an external electrode body 221 and a nickel layer 222 and a tin layer 223 sequentially covering the outer layer of the external electrode body 221. Optionally, when the external electrode body 221 is end-coated, the length and width of the external electrode body 221 on the first main surface 110 and the second main surface 120 of the main body 100 are equal, that is, the area is also equal. After the tin layer 223 and the nickel layer 222 are covered on the outer layer of the external electrode body 221, since the tin layer 223 and the nickel layer 222 on the second main surface 120 fully cover the bottom electrode 121, the width a of the first coverage area 211 on the first main surface 110 will be smaller than the width b of the second coverage area 212 on the second main surface 120.
[0071] Since the bottom electrode 121 on the second main surface 120 needs to be co-fired with the green body of the laminate, the sintering temperature is high and the time is long. Therefore, one or more of the following components such as SiO2, Al2O3, and TiO2 can be added to the electrode slurry of the bottom electrode 121 to improve the bonding force between the bottom electrode 121 and the green body of the laminate.
[0072] The present application will be further described in detail below through some embodiments and performance tests.
[0073] Performance testing mainly includes the following:
[0074] (1) The L value (inductance value) and Q value (quality factor) at 500M frequency were tested using an E4991A impedance analyzer.
[0075] (2) The SRF value (self-resonance frequency) was tested using a network analyzer 5071C.
[0076] Example 1
[0077] This embodiment is a multilayer chip inductor with a metric 0603 size, including a main body 100 and external electrodes. The main body 100 has a multilayer structure formed by stacking multiple conductor patterns 171, and an insulating layer is provided between each pair of adjacent conductor patterns 171. Conductor through holes are formed on the insulating layer, and multiple conductor patterns 171 are connected through the conductor through holes to form a coil.
[0078] The main body 100 has a first main surface 110 and a second main surface 120 disposed opposite to each other along its height direction, a first side surface 130 and a second side surface 140 disposed opposite to each other along its width direction, and a first end surface 150 and a second end surface 160 disposed opposite to each other along its length direction. External electrodes are respectively disposed at both ends of the main body 100 along its length direction, and the external electrodes are connected to the coil.
[0079] Optionally, multiple stacked conductor patterns 171 are arranged sequentially along the height direction of the main body 100. The conductor pattern 171 at the top layer is the lead-in electrode 172, and the conductor pattern 171 at the bottom layer is the lead-out electrode 173. The lead-in electrode 172 and the lead-out electrode 173 are respectively used to connect with the external electrodes at both ends of the main body 100, so that the two external electrodes are respectively connected to the coil.
[0080] Optionally, the external electrode at one end (e.g., the right end) of the main body 100 covers the entire first end surface 150, a portion of the first main surface 110, and a portion of the second main surface 120, while the external electrode at the other end (e.g., the left end) of the main body 100 covers the entire second end surface 160, a portion of the first main surface 110, and a portion of the second main surface 120. Optionally, the external electrode does not cover the first side surface 130 and the second side surface 140.
[0081] Optionally, the external electrodes at both ends of the main body 100 are configured identically. The external electrodes cover the first main surface 110 to form a first covering area 211, and the external electrodes cover the second main surface 120 to form a second covering area 212. The first covering area 211 of the external electrodes is smaller than the second covering area 212.
[0082] Optionally, the length c1 of the first coverage area 211 of the external electrode and the length c2 of the second coverage area 212 are 100%, i.e., the c1 / c2 ratio is 100%; the width a of the first coverage area 211 of the external electrode and the width b of the second coverage area 212 are 50%, i.e., the a / b ratio is 50%. Optionally, the length c1 of the first coverage area 211 is 800 μm, the width a of the first coverage area 211 is 80 μm, the width b of the second coverage area 212 is 160 μm, and the length d of the first main surface 110 is 1600 μm.
[0083] Optionally, the outer electrode body 221 is a silver sintered body, on which a nickel layer 222 and a tin layer 223 are sequentially plated. The area of the nickel layer 222 and the tin layer 223 on the first main surface 110 is the same as the area of the silver sintered body on the first main surface 110, and the area of the nickel layer 222 and the tin layer 223 on the second main surface 120 is the same as the area of the bottom electrode 121. Optionally, the conductor pattern 171 can also be a silver sintered body. Optionally, the insulating layer is made of a SiO2-Al2O3 ceramic sintered body.
[0084] Example 2-12
[0085] The difference between Examples 2-12 and Example 1 lies in the different parameters of the external electrode. Specific parameter settings can be found in Table 1.
[0086] Table 1 Parameter Setting Table
[0087]
[0088] Examples 13-19
[0089] The main difference between Examples 13-19 and Example 1 is that in Examples 13-19, the outer electrode covers the first side surface 130 to form a third covering area 213, and the outer electrode covers the second side surface 140 to form a fourth covering area, and both the third covering area 213 and the fourth covering area are equal to the first covering area 211. Furthermore, the other parameter settings for Examples 13-19 are the same as those for Examples 1-7, and specific parameter settings can be found in Table 1.
[0090] Examples 20-22
[0091] The difference between Examples 20-22 and Example 13 is that the ratio of the third coverage area 213 to the first coverage area 211 is different. For specific parameter settings, please refer to Table 1, the parameter setting table.
[0092] Comparative Examples 1-5
[0093] The difference between Comparative Examples 1-5 and Example 1 is that the parameters of the external electrode are set differently. For specific parameter settings, please refer to Table 1.
[0094] The fabrication methods of the inductors in Examples 1-22 and Comparative Examples 1-5 can be found in steps S100-S300 above. Optionally, the sintering temperature in step S200 can be 900°C, the sintering atmosphere can be air, and the sintering time can be 45 min.
[0095] Optionally, the electrode paste of the bottom electrode 121 may include 65 wt% silver, 1 wt% SiO2, 15 wt% TiO2, 3 wt% resin, 0.1 wt% dispersant, and 15.9 wt% solvent. Optionally, the resin is ethyl cellulose, the dispersant is polyvinyl alcohol, and the solvent is terpineol.
[0096] Table 2 Test Results
[0097]
[0098] Please refer to Table 2 for the test results of Examples 1-22 and Comparative Examples 1-5.
[0099] Based on the test results of Examples 1-22 and Comparative Examples 1-5 above, it can be seen that when the ratio of the width a of the first coverage area 211 to the width b of the second coverage area 212 is 50%, Q and SRF are recorded as Q1 and SRF1, respectively; when the ratio of the width a of the first coverage area 211 to the width b of the second coverage area 212 is 100%, Q and SRF are recorded as Q2 and SRF2, respectively; Q1 is significantly larger than Q2, and SRF1 is also significantly larger than SRF2, and as a / b increases, Q and SRF gradually deteriorate.
[0100] Other configurations and operations of the inductors according to the embodiments of this application are known to those skilled in the art and will not be described in detail here.
[0101] It should be noted that the appendix Figure 3 , 7 The grid in 8 serves to highlight the information.
[0102] In the description of this specification, the use of terms such as "an embodiment," "some examples," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples" indicates that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in the embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0103] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.
[0104] In the description of this application, the presence of a comma ("、") in the patent title indicates an "and" relationship, not an "or" relationship. For example, if the patent title is "A type A, B type", it means that the content claimed in this application is: a technical solution with the subject matter title A and a technical solution with the subject matter title B.
Claims
1. An inductor, characterized in that, include: A main body having a coil formed therein, the coil extending along the height direction of the main body, the main body having a first main surface and a second main surface disposed opposite to each other along its height direction; The outer electrode is provided at both ends of the main body along its length direction. The outer electrode is connected to the coil. The outer electrode covers a portion of the first main surface to form a first covering area. The outer electrode covers a portion of the second main surface to form a second covering area. The first covering area of the outer electrode is smaller than the second covering area.
2. The inductor according to claim 1, characterized in that: The length of the first coverage area is c1, the length of the second coverage area is c2, and the c1 / c2 ratio of the external electrode is 50% to 100%.
3. The inductor according to claim 1, characterized in that: The width of the first coverage area is a, the width of the second coverage area is b, and the width b of the external electrode is greater than or equal to a.
4. The inductor according to claim 3, characterized in that: The a / b ratio of the external electrode is 5% to 90%.
5. The inductor according to claim 4, characterized in that: The length of the first main surface is d, and the a / d ratio is 0.5% to 34%.
6. The inductor according to claim 5, characterized in that: The a / d ratio is 0.5% to 10%.
7. The inductor according to claim 1, characterized in that: The main body has a first side surface and a second side surface disposed opposite to each other along its width direction. The outer electrode covers a portion of the first side surface to form a third covering area, and the outer electrode covers a portion of the second side surface to form a fourth covering area. The second covering area is at least larger than the smaller of the third covering area and the fourth covering area.
8. The inductor according to claim 7, characterized in that: The first coverage area is greater than or equal to the third coverage area, and the first coverage area is greater than or equal to the fourth coverage area.
9. The inductor according to claim 8, characterized in that: The width of the third coverage area and the width of the fourth coverage area are both equal to the width of the first coverage area.
10. The inductor according to claim 1, characterized in that: The main body has multiple stacked conductor patterns, and an insulating layer is provided between each pair of adjacent conductor patterns. Conductor through holes are formed on the insulating layer, and the multiple conductor patterns are connected through the conductor through holes to form the coil.