Mould pressing multi-core-group ceramic capacitor

Abstract

A mould pressing multi-core-group ceramic capacitor comprises an encapsulation shell, two lead frames oppositely arranged in the encapsulation shell and a ceramic chip supported between the two lead frames, and each lead frame comprises a pin frame extending out of the encapsulation shell and a supporting frame connected with the pin frame, arranged in the encapsulation shell and used for supporting the ceramic chip. The support frame comprises a connection section connected with the pin frame, an extension section which is connected with the connection section and extends downwards, and a support section which is connected with the lower end of the extension section and extends along the direction close to the other lead frame; the ceramic chip is supported on the two supporting sections which are oppositely arranged; by limiting the structure of the lead frame, the whole lead frame is enabled to form a plurality of bends, when a product is welded on a PCB (printed circuit board), board bending stress on the PCB is transmitted to the lead frame and is released through the two bends, and the ceramic chip is not affected, so that the mechanical shock vibration resistance of the whole product is improved, and the service life of the product is prolonged. And the reliability of the product can be greatly improved.

Description

Technical Field

[0001] The utility model belongs to the field of ceramic capacitor preparation, and in particular relates to a molded multi-core group ceramic capacitor. Background Art

[0002] With the rapid and continuous development of science and technology, the demand for small-size, large-capacity, and high-power capacitors in fields such as power supply, industry, automobile, military industry, and aerospace is increasing. However, traditional chip ceramic capacitors are difficult to meet the demand for large capacity. In the use conditions of some special equipment, the voltage requirement must reach 5KV or above; however, for ceramic capacitor chips above 5KV, during direct use or testing, the air on the surface of the capacitor is easily broken down due to the high voltage, resulting in arcing on the surface of the capacitor; and when ceramic capacitors are used in harsh environments such as aerospace, more reliable components are required; the characteristic of ceramic chips is that they are resistant to pressure but not to tension. Single chips are directly welded on PCB boards, which are easily affected by board bending stress, limiting the use of ceramic capacitors; further improvement is needed. Utility Model Content

[0003] The utility model aims to overcome the disadvantages of the prior art and provide a molded multi-core ceramic capacitor.

[0004] The utility model adopts the following technical solutions:

[0005] A molded multi-core ceramic capacitor comprises an encapsulating shell, two lead frames arranged relatively in the encapsulating shell and a ceramic chip supported between the two lead frames, wherein the lead frame comprises a lead frame extending out of the encapsulating shell and a support frame connected to the lead frame and arranged in the encapsulating shell for supporting the ceramic chip, wherein the support frame comprises a connecting section connected to the lead frame, an extending section connected to the connecting section and extending downward, and a supporting section connected to the lower end of the extending section and extending in a direction close to another lead frame; the ceramic chip is supported on the two supporting sections arranged relatively.

[0006] Furthermore, the lead frame includes a positioning section connected to the connecting section, a fitting section connected to the positioning section and extending downwardly to fit on the side of the encapsulating shell, and a lead section arranged at the bottom of the encapsulating shell and connected to the lower end of the fitting section.

[0007] Furthermore, the fitting section and the extending section partially overlap and face each other.

[0008] Furthermore, the width of the support segment is greater than the width of the pin segment.

[0009] Furthermore, the support segment extends above a lead segment of another lead frame.

[0010] Furthermore, the fitting section is arranged inwardly and tilted on the outer side of the encapsulating shell.

[0011] Furthermore, the fitting section is located in the middle of the encapsulating shell.

[0012] Furthermore, a solder layer is provided between the support section and the ceramic chip.

[0013] Furthermore, the ceramic chip includes a chip body and two external electrode layers relatively arranged at both ends of the chip body, the chip body is formed by stacking and firing multiple dielectric layers, the dielectric layer includes a dielectric layer and an internal electrode group printed on the dielectric layer, and the internal electrode group includes a first internal electrode layer and a second internal electrode layer spaced apart from each other.

[0014] Furthermore, the first inner electrode layer includes five first inner electrodes arranged at intervals, and the two first inner electrodes located on the left and right sides are respectively connected to the opposite outer electrode layer; the second inner electrode layer includes four second inner electrodes arranged at intervals, and the two ends of the second inner electrode are respectively opposite to the two adjacent first inner electrodes.

[0015] From the above description of the utility model, it can be seen that compared with the prior art, the beneficial effect of the utility model is: the present application limits the structure of the lead frame so that the entire lead frame is formed with multiple bends. When the product is welded on the PCB board, the board bending stress on the PCB board is transferred to the lead frame and released through these two bends without affecting the ceramic chip, thereby increasing the ability of the entire product to resist mechanical shock and vibration, which can greatly improve the reliability of the product and can be applied to more complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The structure of the utility model is shown in FIG. Figure 1 ;

[0017] Figure 2 The structure of the utility model is shown in FIG. Figure 2 ;

[0018] Figure 3 Schematic diagram of the lead frame structure Figure 1 ;

[0019] Figure 4 Schematic diagram of the lead frame structure Figure 2 ;

[0020] Figure 5 It is a structural cross-sectional view of a ceramic chip;

[0021] Figure 6 is the equivalent circuit diagram of a ceramic capacitor;

[0022] In the figure, 1-encapsulating shell, 2-lead frame, 3-ceramic chip, 21-lead rack, 211-positioning section, 212-fitting section, 213-lead section, 22-support frame, 221-connecting section, 222-extension section, 223-support section, 23-solder layer, 31-chip body, 311-dielectric layer, 312-inner electrode group, 313-first inner electrode, 314-second inner electrode, 32-outer electrode layer. DETAILED DESCRIPTION

[0023] The present invention is further described below through specific implementation methods.

[0024] Reference Figures 1 to 6 As shown, a molded multi-core ceramic capacitor comprises an encapsulating shell 1 , two lead frames 2 arranged oppositely in the encapsulating shell 1 , and a ceramic chip 3 supported between the two lead frames 2 .

[0025] The encapsulating shell 1 is made of epoxy resin material. Specifically, the epoxy resin material is a polymerization product of epichlorohydrin and bisphenol A. It has extremely excellent dielectric properties, mechanical properties, bonding properties, and corrosion resistance, and has small curing shrinkage and linear expansion coefficient, good dimensional stability, and good process performance. The encapsulation form of the ceramic chip 3 using the encapsulating shell 1 strengthens the structural strength of the entire product, improves the product's ability to resist mechanical shock and vibration, and has stronger reliability and can be used in more complex environments. In addition, by encapsulating with epoxy resin material, a vacuum state can be achieved in the cavity, and the ceramic chip 3 is isolated from the air, thereby increasing the insulation performance of the product and preventing the occurrence of arcing.

[0026] The lead frame 2 includes a lead frame 21 extending outward from the encapsulating shell 1 and a support frame 22 connected to the lead frame 21 and arranged in the encapsulating shell 1 for supporting the ceramic chip 3. Specifically, the support frame 22 includes a connecting section 221 connected to the lead frame 21, an extending section 222 connected to the connecting section 221 and extending downward, and a supporting section 223 connected to the lower end of the extending section 222 and extending in a direction close to another lead frame. The ceramic chip 3 is supported on two supporting sections 223 arranged opposite to each other. Furthermore, a solder layer 23 is arranged between the supporting section 223 and the bottom of the ceramic chip 3, wherein the solder layer 23 uses high-temperature solder, and the composition of the high-temperature solder is Sn. 10 Pb 90 The high temperature solder has a melting point of 287°C after welding, which can prevent the risk of the lead frame 2 and the ceramic chip 3 falling apart during customer use.

[0027] The lead frame 21 includes a positioning section 211 connected to the connecting section 221, a bonding section 212 connected to the positioning section 211 and extending downward to be bonded to the side of the encapsulating shell 1, and a pin section 213 arranged at the bottom of the encapsulating shell 1 and connected to the lower end of the bonding section 212; specifically, the bonding section 212 and the extension section 222 partially overlap and face each other, and the bonding section 212 is located in the middle of the side of the encapsulating shell 1, and the positional relationship between the bonding section 212 and the extension section 222 is limited to facilitate the molding of the bonding section 212 and the pin section 213 during the preparation process, thereby reducing the occurrence of breakage of the lead frame 21; in addition, the support section 223 extends to the upper end of the pin section of another lead frame, so that the width of the support section 223 is greater than the width of the pin section 213. After welding the ceramic chip 3, the overall appearance is more beautiful, and the high-temperature solder has a better tin-climbing effect. At the same time, the structural strength is better, which can better support the ceramic chip 3, reduce the ESR of the lead frame 2, and facilitate the current flow. According to the formula of thermal power calculation formula P=I 2 R, the internal resistance becomes smaller, which can reduce internal heat, improve the thermal stability of the product, and ensure the quality of the product; further, the fitting section 212 is arranged inwardly on the outer side of the encapsulation shell 1, so that during molding, the encapsulation material is not likely to fail to fully encapsulate the ceramic chip and collapse the edge.

[0028] The ceramic chip 3 includes a chip body 31 and two outer electrode layers 32 arranged at both ends of the chip body 31. The chip body 31 is formed by stacking and firing a plurality of dielectric layers. The dielectric layer includes a dielectric layer 311 and an inner electrode group 312 printed on the dielectric layer 311. The inner electrode group 312 includes a first inner electrode layer and a second inner electrode layer arranged at intervals from top to bottom. Specifically, the first inner electrode layer includes five first inner electrodes 313 arranged at intervals, and the two first inner electrodes 313 located on the left and right sides are respectively connected to the opposite outer electrode layer 32; the second inner electrode layer includes four second inner electrodes 314 arranged at intervals, and the two ends of the second inner electrode 314 are respectively opposite to the two adjacent first electrodes 313, so that the first inner electrode layer and the second inner electrode layer form 8 small capacitors connected in series, realizing the role of voltage division, so that the withstand voltage of the prepared ceramic capacitor reaches 10,000 volts; further, the outer periphery of the ceramic chip 3 is coated with a three-proof paint, which can increase the cleanliness of the surface of the ceramic chip 3 and improve the insulation performance of the surface of the ceramic chip 3; it can also play a buffering role to prevent the ceramic chip from being damaged due to the high molding pressure during the molding process.

[0029] The preparation process specifically comprises the following steps:

[0030] Step 1: Apply high temperature solder on the support section 223 of the lead frame 2, and stack the ceramic chip 3 at the solder paste position through an SMT placement machine;

[0031] Step 2: Use a jig to assemble and position the ceramic chip 3 and the lead frame 2, and put the positioned products into a 300° C. reflow soldering process for soldering;

[0032] Step 3: Perform ultrasonic cleaning on the welded product to remove excess flux on the product;

[0033] Step 4, coating a layer of conformal coating on the surface of the ceramic chip 3, and then feeding it into a molding device for encapsulation to form an encapsulation shell 1;

[0034] Step five, the molded product is subjected to molding of the lead frame 21, and the molded product is subjected to electroplating, where a layer of tin-lead is electroplated on the lead frame 2 to ensure the solderability of the obtained ceramic capacitor.

[0035] The present application limits the structure of the lead frame 2 so that the entire lead frame 2 is formed with multiple bends. When the product is welded on the PCB board, the board bending stress on the PCB board is transferred to the lead frame 2 and released through these two bends without affecting the ceramic chip, thereby increasing the ability of the entire product to resist mechanical shock and vibration, which can greatly improve the reliability of the product and enable it to be applied in more complex environments.

[0036] The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of implementation of the present invention. That is, equivalent changes and modifications made according to the scope of application of the present invention and the contents of the specification should still fall within the scope covered by the present invention.

Claims

1. A molded multi-core ceramic capacitor, characterized in that: It includes an encapsulating shell, two lead frames relatively arranged in the encapsulating shell and a ceramic chip supported between the two lead frames, the lead frame includes a lead frame extending out of the encapsulating shell and a support frame connected to the lead frame and arranged in the encapsulating shell for supporting the ceramic chip, the support frame includes a connecting section connected to the lead frame, an extending section connected to the connecting section and extending downward, and a supporting section connected to the lower end of the extending section and extending in a direction close to the other lead frame; the ceramic chip is supported on the two supporting sections relatively arranged.

2. The molded multi-core ceramic capacitor according to claim 1, characterized in that: The lead frame includes a positioning section connected to the connecting section, a fitting section connected to the positioning section and extending downward to fit the side of the encapsulating shell, and a lead section arranged at the bottom of the encapsulating shell and connected to the lower end of the fitting section.

3. The molded multi-core ceramic capacitor according to claim 2, characterized in that: The fitting section and the extending section partially overlap and face each other.

4. The molded multi-core ceramic capacitor according to claim 2, characterized in that: The width of the supporting section is greater than the width of the pin section.

5. The molded multi-core ceramic capacitor according to claim 2, characterized in that: The support segment extends above a lead segment of another lead frame.

6. The molded multi-core ceramic capacitor according to claim 2, characterized in that: The fitting section is arranged inwardly and tiltedly on the outer side of the encapsulating shell.

7. The molded multi-core ceramic capacitor according to claim 2, characterized in that: The fitting section is located in the middle of the encapsulating shell.

8. The molded multi-core ceramic capacitor according to claim 1, characterized in that: A solder layer is arranged between the supporting section and the ceramic chip.

9. The molded multi-core ceramic capacitor according to claim 1, characterized in that: The ceramic chip includes a chip body and two outer electrode layers arranged at two ends of the chip body. The chip body is formed by stacking and firing multiple dielectric layers. The dielectric layer includes a dielectric layer and an inner electrode group printed on the dielectric layer. The inner electrode group includes a first inner electrode layer and a second inner electrode layer spaced apart from each other.

10. The molded multi-core ceramic capacitor according to claim 9, characterized in that: The first inner electrode layer includes five first inner electrodes arranged at intervals, and the two first inner electrodes located on the left and right sides are respectively connected to the opposite outer electrode layer; the second inner electrode layer includes four second inner electrodes arranged at intervals, and the two ends of the second inner electrode are respectively opposite to the two adjacent first inner electrodes.

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