A double L-shaped pin ceramic capacitor and a manufacturing method thereof

Abstract

A double-L type pin ceramic capacitor and a preparation method thereof, the double-L type pin ceramic capacitor comprises two supports arranged oppositely, one or more ceramic chips arranged between the two supports, and two first solder layers respectively arranged between the end of the one or more ceramic chips and the opposite support, the support comprises two frames arranged symmetrically and a second solder layer arranged between the two frames, the frame comprises a frame body, a plurality of L type pins arranged at intervals on the bottom of the frame body, a plurality of support plates arranged between adjacent two L type pins, and a plurality of exhaust holes arranged uniformly on the frame body; by limiting the structure of the ceramic capacitor, the two frames arranged symmetrically are welded to each other as the support through the solder, so that the welding area of the prepared support and the PCB board is doubled, the welding strength of the prepared ceramic capacitor is improved, and the bonding strength of the ceramic capacitor and the PCB board is better.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of ceramic capacitor preparation, and particularly relates to a double-L type pin ceramic capacitor and a preparation method thereof. BACKGROUND

[0002] With the rapid and continuous development of science and technology, the demand for small size, large capacity and large power capacitors is increasing in fields such as power supply, industry, automobile, military and aerospace. The traditional chip ceramic capacitor is difficult to meet the demand of large capacity, so the way of parallel assembly of multiple ceramic capacitors is used to realize the demand of large capacity of capacitors.

[0003] In harsh environments such as aerospace, more reliable components are needed. The characteristic of ceramic chip is that it can resist pressure but not tension. The single chip is directly welded on the PCB board, which is easy to be affected by the bending stress of the board. Therefore, the lead and the chip are welded together, and the bending stress of the board will act on the lead, and will not affect the ceramic chip, thereby solving the problem of bending stress of the board. However, the existing L-shaped pin structure has insufficient strength, small contact area with the PCB board, and cannot adapt to higher strength vibration test, which greatly limits its application occasions and needs to be further improved. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art and provide a double-L type pin ceramic capacitor with high welding strength and good vibration resistance. Another purpose is to provide a method for preparing the above ceramic capacitor.

[0005] The application adopts the following technical solutions:

[0006] A double-L type pin ceramic capacitor comprises two brackets arranged oppositely, one or more ceramic chips arranged between the two brackets, and two first solder layers arranged between the end of the one or more ceramic chips and the opposite bracket, respectively.

[0007] The frame comprises a frame body, a plurality of L-shaped pins arranged at intervals at the bottom of the frame body, a plurality of support plates arranged between adjacent two L-shaped pins, and a plurality of exhaust holes arranged uniformly on the frame body. The plurality of L-shaped pins of the two frames are arranged in a stack at the lower end of the bracket.

[0008] Further, a space is formed between the adjacent two L-shaped pins, and the support plate is arranged in the space.

[0009] Further, the double-L type pin comprises a vertical segment connected with the frame body and a horizontal segment arranged perpendicularly to the vertical segment, the support plate is arranged higher than the horizontal segment, and the horizontal segment is arranged in the same direction as the support segment.

[0010] A preparation method of a double L-shaped pin ceramic capacitor comprises the following steps:

[0011] In step one, a frame is placed in a frame welding jig with the L-shaped pin downward, then a second solder is coated on the opposite surface of the frame, and then another frame is placed to be attached with the second solder and with the L-shaped pin upward; the frame welding jig is assembled and sent into a reflow soldering furnace for soldering to obtain the support;

[0012] In step two, the soldered support is placed in a finished product welding jig, a first solder is coated on the opposite surface of the support and another support, then one or more ceramic chips are stacked according to the requirement, then the first solder is coated on the end of the stacked one or more ceramic chips, and then another support is placed; the finished product welding jig is assembled with the L-shaped pins of the supports upward, and then sent into a reflow soldering furnace for soldering to obtain the double L-shaped pin ceramic capacitor.

[0013] Further, in step one, the temperature of the reflow soldering is 290-310 DEG C; in step two, the temperature of the reflow soldering is 250-270 DEG C.

[0014] Further, the frame welding jig comprises a base, a pressing block arranged on the base, and a positioning mechanism arranged between the base and the pressing block, the base is provided with a soldering groove for mounting the frame, and the opposite surface of the pressing block and the base is formed with a positioning part which can be embedded in the soldering groove and abut against the frame.

[0015] Further, the positioning mechanism comprises two positioning columns which are oppositely arranged on the base and extend upward, and two positioning holes which are arranged on the pressing block and can be embedded by the two positioning columns respectively.

[0016] Further, the finished product welding jig comprises an upper die base and a lower die base which are oppositely arranged, and a limiting mechanism arranged between the upper die base and the lower die base, the opposite surface of the upper die base and the lower die base is formed with an upper mounting groove which extends upward and is used for mounting the support and the end of the ceramic chip, and the opposite surface of the lower die base and the upper die base is formed with a lower mounting groove which extends downward and is used for mounting the support and the end of the ceramic chip.

[0017] Further, the upper mounting groove comprises a first upper mounting groove and a second upper mounting groove which are arranged in sequence from top to bottom, the length of the second upper mounting groove is greater than that of the first upper mounting groove, the support opposite to the upper die base is arranged in the first upper mounting groove, and the end of the ceramic chip opposite to the upper die base is arranged in the second upper mounting groove.

[0018] Further, the limiting mechanism comprises two limiting columns which are oppositely arranged on the upper die base, and two limiting holes which are arranged on the upper die base and can be embedded by the two limiting columns oppositely.

[0019] From the above description of the present application, compared with the prior art, the beneficial effects of the present application are: by limiting the structure of the ceramic capacitor, the two frames arranged symmetrically are welded to each other by solder as a support, so that the welding area of the prepared support and the PCB board is doubled, the welding strength of the prepared ceramic capacitor is improved, the bonding strength of the ceramic capacitor and the PCB board is better, compared with the single-frame ceramic capacitor, it can withstand higher strength vibration, improve the reliability of the product, and can be applied to high-reliability occasions such as aerospace. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 Structure diagram of ceramic capacitor Figure One ;

[0021] Figure 2 Structure diagram of ceramic capacitor Figure Two ;

[0022] Figure 3 Structure diagram of support Figure One ;

[0023] Figure 4 Structure diagram of support Figure Two ;

[0024] Figure 5 Structure diagram of frame welding jig Figure One ;

[0025] Figure 6 Structure diagram of frame welding jig Figure Two ;

[0026] Figure 7 Structure diagram of frame welding jig Figure Three ;

[0027] Figure 8 Structure diagram of finished product welding jig Figure One ;

[0028] Figure 9 Structure diagram of finished product welding jig Figure Two ;

[0029] Figure 10 Structure diagram of finished product welding jig Figure Three ;

[0030] Figure 11 Structure diagram of finished product welding jig Figure Four ;

[0031] Figure 12 Structure diagram of finished product welding jig Figure Five ;

[0032] Figure 13Fig. 1 is a cross-sectional view of the internal structure of a ceramic chip;

[0033] In the figure, 1 is a bracket, 2 is a ceramic chip, 3 is a first solder layer, 4 is a frame, 5 is a second solder layer, 6 is a frame welding jig, 7 is a finished product welding jig, 21 is a capacitor chip body, 22 is an outer electrode layer, 221 is a first outer electrode, 222 is a second outer electrode, 223 is a third outer electrode, 23 is a dielectric layer, 24 is a first inner electrode layer, 241 is a first long inner electrode, 242 is a first short inner electrode, 25 is a second inner electrode layer, 251 is a second short inner electrode, 252 is a second long inner electrode, 41 is a frame body, 42 is an L-shaped pin, 421 is a vertical section, 422 is a horizontal section, 43 is a support plate, 44 is an exhaust hole, 45 is a space area, 61 is a base, 611 is a welding groove, 62 is a pressing block, 621 is a positioning part, 622 is a heat dissipation hole, 63 is a positioning mechanism, 631 is a positioning column, 632 is a positioning hole, 71 is an upper die holder, 711 is an upper mounting groove, 712 is a first upper mounting groove, 713 is a second upper mounting groove, 72 is a lower die holder, 721 is a lower mounting groove, 722 is a first lower mounting groove, 723 is a second lower mounting groove, 73 is a limiting mechanism, 731 is a limiting column, and 732 is a limiting hole. DETAILED DESCRIPTION

[0034] The application will be further described below through specific embodiments.

[0035] Referring to Figures 1 to 13 As shown in the figure, a double L-shaped pin ceramic capacitor includes two brackets 1 arranged oppositely, one or more ceramic chips 2 arranged between the two brackets 1, and a first solder layer 3 arranged at the end of each ceramic chip 2 and the opposite bracket 1.

[0036] The bracket 1 includes two frames 4 arranged symmetrically and a second solder layer 5 arranged between the two frames 4, wherein the melting point of the second solder layer 5 is higher than that of the first solder layer 3, so that the second solder layer 5 will not melt during secondary reflow soldering, thereby avoiding the risk of the bracket 1 being scattered. Specifically, the second solder layer 5 uses a tin-lead alloy solder with a composition of Sn10Pb90, and the melting point of the solder after welding is 287℃; the first solder layer 3 uses a tin-antimony alloy solder with a composition of Sn90Sb10, and the melting point of the solder after welding is 240℃.

[0037] The frame 4 comprises a frame body 41, a plurality of L-shaped pins 42 arranged at the bottom of the frame body 41, a plurality of support plates 43 arranged between adjacent two L-shaped pins 42, and a plurality of exhaust holes 44 arranged on the frame body 41. The plurality of L-shaped pins 42 of the two frames 4 are symmetrically arranged at the lower end of the support 1. By arranging the plurality of exhaust holes 44 on the frame body 41, not only heat can be dissipated during the welding process of the support 1, but also the flux evaporated in the solder can be discharged through the exhaust holes 44, so that the second solder layer 5 is more dense. Specifically, the two L-shaped pins 42 form a space 45 therebetween, and the support plate 43 is arranged in the space 45. Further, the double L-shaped pin 42 comprises a vertical section 421 connected with the frame body 41 and a horizontal section 422 arranged perpendicularly to the vertical section 421. The support plate 43 is arranged in the same direction as the horizontal section 422 and is arranged higher than the horizontal section 422.

[0038] The ceramic chip 2 comprises a capacitor chip body 21 and two outer electrode layers 22 arranged opposite to the two ends of the capacitor chip body 21. The capacitor chip body 21 is formed by stacking and firing a plurality of dielectric layers. The dielectric layer comprises a dielectric layer 23 and an inner electrode group printed on the dielectric layer 23. The inner electrode group comprises a plurality of first inner electrode layers 24 and second inner electrode layers 25 arranged alternately. Specifically, the first inner electrode layer 24 comprises a first long inner electrode 241 and a first short inner electrode 242 arranged alternately. The second inner electrode layer 25 comprises a second short inner electrode 251 and a second long inner electrode 252 arranged alternately. The first long inner electrode 241 and the second long inner electrode 252 are arranged alternately. Further, the material of the dielectric layer 23 is barium titanate ceramic, and the material of the inner electrode group is palladium silver metal.

[0039] The outer electrode layer 22 comprises a first outer electrode 221, a second outer electrode 222 and a third outer electrode 223 arranged from inside to outside. The first outer electrode on the left side is connected with the second short inner electrode 251, and the first outer electrode on the right side is connected with the first short inner electrode 242.

[0040] A preparation method of a double L-shaped pin ceramic capacitor, comprising the following steps:

[0041] Step one, first place a frame 4 in the frame welding jig 6, so that the L-shaped pin 42 is arranged downward, then coat the second solder on the opposite surface of the other frame, then place the other frame, which is combined with the second solder, and arrange the L-shaped pin upward; then assemble the frame welding jig 5, and send it into the reflow soldering furnace to perform welding at 290-310℃, to obtain the support 1.

[0042] Step two, put the welded bracket 1 into the finished product welding fixture 7, and coat the first solder on the opposite side of the bracket 1 and another bracket, then stack one or more ceramic chips 2 as required, then coat the first solder on the end of the stacked one or more ceramic chips 2, and place another bracket; Assemble the finished product welding fixture 7, with the multiple L-shaped pins 42 of the bracket facing up, and send it into the reflow soldering furnace for welding at 250-270°C to obtain the double L-shaped pin ceramic capacitor.

[0043] Wherein, the frame welding fixture 6 comprises a base 61, a pressing block 62 arranged on the base 61, and a positioning mechanism 63 arranged between the base 61 and the pressing block 62, specifically, the base 61 is provided with a welding groove 611 for mounting the frame 4; the opposite surface of the pressing block 62 and the base 61 is formed with a positioning portion 621 which can be embedded in the welding groove 611 and abut against the frame 4; the positioning mechanism 63 comprises two positioning columns 631 arranged oppositely on the base 61 and extending upward, and two positioning holes 632 arranged on the pressing block 62 and capable of embedding the two positioning columns 631 respectively; further, the pressing block 62 is provided with a heat dissipation hole 622 extending inward from the top surface thereof and opposite to the welding groove 611, which not only can dissipate heat, but also can allow the flux evaporated from the solder to be discharged through the heat dissipation hole 622; when welding the frame 4, first place a frame 4 in the welding groove 611, then coat the second solder and stack another frame to make it adhere to the second solder; then, through the cooperation of the positioning columns 631 and the positioning holes 632, the positioning portion 621 on the pressing block 62 is embedded in the welding groove 611 and abuts against the frame above to press the two frames 4 tightly; after reflow soldering, stable connection between the two frames 4 is ensured.

[0044] The finished product welding jig 7 comprises an upper die holder 71 and a lower die holder 72 arranged oppositely and a limiting mechanism 73 arranged between the upper die holder 71 and the lower die holder 72, wherein the opposite surface of the upper die holder 71 and the lower die holder 72 is formed with an upper mounting groove 711 extending upward for mounting the opposite support and the end of the plurality of ceramic chips; the opposite surface of the lower die holder 72 and the upper die holder 71 is formed with a lower mounting groove 721 extending downward for mounting the opposite support and the end of the ceramic chip; the limiting mechanism 73 comprises two limiting columns 731 arranged oppositely on the upper die holder 71 and two limiting holes 732 arranged on the upper die holder 71 for embedding the opposite limiting columns 731; specifically, the upper mounting groove 711 comprises a first upper mounting groove 712 and a second upper mounting groove 713 arranged in sequence from top to bottom, and the length of the second upper mounting groove 713 is longer than the length of the first upper mounting groove 712, the support opposite to the upper die holder 71 is arranged in the first upper mounting groove 712, and the end of the ceramic chip opposite to the upper die holder 71 is arranged in the second upper mounting groove 713; the lower mounting groove 721 comprises a first lower mounting groove 722 and a second lower mounting groove 723 arranged in sequence from top to bottom, and the length of the first lower mounting groove 722 is longer than the length of the second lower mounting groove 723, the support opposite to the lower die holder 72 is arranged in the second lower mounting groove 723, and the end of the ceramic chip opposite to the lower die holder is arranged in the first lower mounting groove 722; during the finished product welding, first, a support 1 is placed in the second lower mounting groove 721, then the first solder is coated, and according to the requirements, one or more ceramic chips 2 are stacked on the first solder; then the end of the one or more ceramic chips 2 is coated with the first solder, and another support is attached to the coated first solder; then the upper die holder 71 and the lower die holder 72 are pressed tightly through the cooperation of the limiting columns 731 and the limiting holes 732, at the same time, the plurality of L-shaped pins 42 of the support 1 are placed upward, and the support is sent into a reflow soldering furnace for welding at 250-270℃ to obtain a double-L-shaped pin ceramic capacitor; during the reflow soldering, the plurality of L-shaped pins 42 are placed upward to avoid the tin climbing phenomenon in the welding process, prevent the first solder from gathering at the bottom of the support pin after melting, which affects the appearance of the product and reduces the bending resistance of the product.

[0045] A single frame is used as a support, and a ceramic capacitor is prepared by the method defined in the application as a comparative example. Then, a double-L-shaped pin ceramic capacitor prepared by the application and the comparative example are subjected to a vibration finite element simulation test, wherein the experimental conditions and steps are as follows:

[0046] (a) Before the test, the test parameters are set (as shown in Table 1), and the test is carried out under the standard atmospheric conditions of the test. The appearance of the test product is inspected before the test, and the function and performance of the test product are detected. The appearance is inspected and the results are recorded;

[0047] (b) The test product is subjected to a specified 36h vibration test under the specified test conditions. After the vibration function test, the function and performance of the test product are detected and recorded.

[0048] (c) After the end of the test, the appearance inspection and function, performance detection are carried out on the test product under the standard atmospheric conditions of the test, and the appearance inspection result is recorded.

[0049] Specific results, see Table 1 and Table 2.

[0050] Table 1 vibration test spectrum value condition

[0051]

[0052] Table 2 simulation result table

[0053]

[0054]

[0055] From the data in Table 2, after 36h vibration, the root mean square stress of the support and the welding point position of the double L frame structure is 98.25MPa, 10.14MPa respectively, and the root mean square stress of the support and the welding point position of the single L frame structure is 315.2MPa, 56.71MPa respectively. The data of the double L structure is much smaller than that of the single L structure, so the vibration resistance of the double L structure is stronger than that of the single L structure.

[0056] The application limits the structure of the ceramic capacitor, and the two frames 4 arranged symmetrically are welded to each other as supports 1 by solder, so that the welding area of the prepared support 1 and the PCB board is doubled, the welding strength of the prepared ceramic capacitor is improved, the bonding strength of the ceramic capacitor and the PCB board is better, and compared with the single frame ceramic capacitor, the ceramic capacitor can withstand higher strength vibration, improve the reliability of the product, and can be applied to high reliability occasions such as aerospace.

[0057] The above is only a preferred embodiment of the present application, and therefore cannot limit the scope of the present application, that is, equivalent changes and modifications made according to the scope of the present application and the content of the specification should still be within the scope of the present application.

Claims

1. A method for fabricating a dual L-type lead ceramic capacitor, characterized in that: The dual L-shaped lead ceramic capacitor includes two opposing supports and one or more ceramic chips disposed between the two supports. The supports include two symmetrically arranged frames, and each frame includes a plurality of L-shaped leads spaced apart at its bottom. The preparation method includes the following steps: Step 1: First, place one frame in the frame welding fixture with the L-shaped pins facing down. Then, apply a second solder to the surface opposite the other frame. Next, place the other frame, attach it to the second solder, and set its L-shaped pins upward. Then, assemble the frame welding fixture and send it into the reflow oven for welding to obtain the bracket. Step 2: Place the welded bracket into the finished welding fixture, apply the first solder to the opposite surface of the bracket and another bracket, then stack one or more ceramic chips as required, apply the first solder to the ends of the stacked one or more ceramic chips, and place another bracket; then assemble the finished welding fixture, with the multiple L-shaped pins of the bracket facing upwards, and send it into the reflow oven for welding to obtain the double L-shaped pin ceramic capacitor. The finished product welding fixture includes an upper mold base and a lower mold base arranged opposite to each other and a limiting mechanism disposed between the upper mold base and the lower mold base. The opposing surfaces of the upper mold base and the lower mold base are formed with an upper mounting groove extending upward for mounting a bracket and the ends of multiple ceramic chips. The opposing surfaces of the lower mold base and the upper mold base are formed with a lower mounting groove extending downward for mounting a bracket and the ends of ceramic chips. The upper mounting slot includes a first upper mounting slot and a second upper mounting slot arranged sequentially from top to bottom. The length of the second upper mounting slot is greater than the length of the first upper mounting slot. A bracket opposite to the upper mold base is disposed in the first upper mounting slot, and the ceramic chip end opposite to the upper mold base is disposed in the second upper mounting slot. The limiting mechanism includes two limiting posts disposed opposite to each other on the upper mold base and two limiting holes disposed on the upper mold base for the relative limiting posts to be inserted.

2. The method for preparing a dual L-type lead ceramic capacitor according to claim 1, characterized in that: In step one, the reflow soldering temperature is 290-310℃; in step two, the reflow soldering temperature is 250-270℃.

3. The method for preparing a dual L-type lead ceramic capacitor according to claim 1, characterized in that: The frame welding fixture includes a base, a pressure block disposed on the base, and a positioning mechanism disposed between the base and the pressure block. The base is provided with a welding groove for mounting the frame, and the pressure block and the opposite surface of the base form a positioning part that can be embedded in the welding groove and abut against the frame.

4. The method for preparing a dual L-type lead ceramic capacitor according to claim 3, characterized in that: The positioning mechanism includes two positioning posts that are arranged opposite each other on the base and extend upwards, and two positioning holes that are arranged on the pressure block for the two positioning posts to be inserted into respectively.

5. A dual L-type lead ceramic capacitor, characterized in that: The device is prepared by the method according to any one of claims 1 to 4, comprising two supports disposed opposite to each other, one or more ceramic chips disposed between the two supports, and two first solder layers respectively disposed between the ends of the one or more ceramic chips and the opposing supports. The supports include two symmetrically arranged frames and a second solder layer disposed between the two frames. The frame includes a frame body, a plurality of L-shaped pins spaced apart at the bottom of the frame body, a plurality of support plates disposed between two adjacent L-shaped pins, and a plurality of vent holes evenly arranged on the frame body. The plurality of L-shaped pins of the two frames are stacked at the lower end of the support.

6. A dual L-type lead ceramic capacitor according to claim 5, characterized in that: A clearance area is formed between two adjacent L-shaped pins, and the support plate is disposed in the clearance area.

7. A dual L-type lead ceramic capacitor according to claim 5, characterized in that: The dual L-shaped pins include a vertical section connected to the frame body and a horizontal section arranged perpendicular to the vertical section. The support plate is set higher than the horizontal section, and the horizontal section is set in the same direction as the support section.

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