Silk-screen printing equipment of high-voltage MLCC capacitor, capacitor and preparation method of capacitor

Abstract

The invention discloses screen printing equipment of a high-voltage MLCC capacitor, the capacitor and a preparation method of the capacitor, and relates to the field of screen printing equipment of the capacitor, the capacitor and the preparation method of the capacitor, the screen printing equipment comprises a printing screen, and the printing screen comprises an alignment marking piece which is set to adjust and confirm a printing position; the cutting marking piece is used for indicating the position where the printed ceramic film needs to be cut into single MLCC units; the electrode pattern area is set to be capable of printing an inner electrode pattern consistent with the electrode slurry on the ceramic thin film when the electrode slurry is brushed; wherein the electrode pattern area comprises a first area and a second area. According to the printing equipment, the printing screen of the printing equipment is arranged to comprise the first area and the second area which are different in pattern, the creepage distance between the end electrode and the inner electrode is increased while the consistency is guaranteed, and the purpose of reducing the risks of electric field distortion and peak discharge is achieved.

Description

Technical Field

[0001] The present invention relates to the field of screen printing equipment for capacitors, capacitors and preparation methods thereof, and in particular to screen printing equipment for high-voltage MLCC capacitors, capacitors and preparation methods thereof. Background Art

[0002] In the production process of MLCC capacitors (multilayer ceramic capacitors), screen printing equipment plays a key role. It determines the accuracy of the electrode pattern and the product quality. Through screen printing technology, the inner electrodes can be accurately printed between the ceramic layers of the MLCC capacitor to form a conductive path for the capacitor.

[0003] The high-voltage MLCC capacitors currently on the market generally have several identical capacitors connected in series, and the printed screen is composed of multiple identical electrode patterns. The advantage of this approach is that it uses a screen printing device with high alignment accuracy and simple operation. The disadvantage is that the length of the inner electrode at the two end electrode wrapping positions can only be 1 / 2 of the length of the middle suspended inner electrode (see Figure 1 ), and cannot extend to areas beyond the wrapping position. Since the edge of the terminal electrode is the junction of two materials and has an irregular shape, the electric field is distorted here, which is prone to spike discharge. The shorter the creepage distance between the terminal electrode wrapping part and the opposite inner electrode, the higher the risk of discharge.

[0004] Another approach is to use two different electrode patterns to superimpose, although it can increase the creepage distance between the terminal electrode and the inner electrode (see Figure 2 ), but the current screen printing equipment on the market can usually only print a single pattern at a time, which leads to low production efficiency. Furthermore, when the internal structure of the capacitor requires two or more different patterns to be superimposed, since the two patterns are printed using different screen equipment, the errors that may occur during multiple positioning and printing processes make it difficult to ensure the dimensional consistency between different patterns, which in turn affects the electrical performance of the capacitor and the product qualification rate.

[0005] In view of this, this application is filed. Summary of the invention

[0006] The object of the present invention is to provide a screen printing device for MLCC capacitors, a capacitor and a preparation method thereof, by setting the printing screen of the printing device to include a first area and a second area with two different graphics, so as to solve the problem in the prior art that exactly the same electrode pattern cannot extend to the area outside the wrapping position and it is difficult to ensure consistency when printing different graphics using different screen devices.

[0007] First, an embodiment of the present invention provides a screen printing device for an MLCC capacitor, including a printing screen, wherein the printing screen includes:

[0008] A registration mark, which is set to adjust and confirm the printing position;

[0009] Cutting markers to indicate where the ceramic film needs to be cut into individual MLCC units after printing;

[0010] The electrode pattern area is configured to print an inner electrode pattern consistent with the pattern on the ceramic film when the electrode slurry is applied;

[0011] The electrode pattern area includes a first area and a second area, and the pattern of the first area is different from the pattern of the second area.

[0012] Furthermore, the first area and the second area are arranged adjacent to each other in a transverse direction, the first area includes five transversely arranged patterns, and the lengths of the two patterns on the left side and the right side are respectively b, and the lengths of the three middle patterns are respectively a;

[0013] The second region includes four transversely arranged patterns, and the lengths of the four transversely arranged patterns in the second region are respectively a;

[0014] The b is greater than a, and the b is greater than the wrapping width of the terminal electrode.

[0015] Further, the pattern with a length of b is arranged to extend into the second region adjacent thereto, and its length in the second region is c;

[0016] c is greater than zero, and there is a gap between the pattern with a length of b and the pattern in the second region.

[0017] Furthermore, 80 μm>c>120 μm. By setting the range of c, it can be ensured that during the cutting process, the extended inner electrode portion will be neither too short to form an effective virtual electrode nor too long to affect the normal function of other electrodes or cause unnecessary material waste.

[0018] In order to better solve the above problems, the embodiments of the present invention also provide a capacitor and a method for preparing the same, wherein the capacitor uses the above screen printing device to print the internal electrode. The above screen printing device can achieve high-precision alignment to ensure accurate printing of the internal electrode pattern. Using a single screen printing device can simplify the operation process and improve production efficiency. By optimizing the structure of the screen printing device, such as extending the pattern of the first area to the second area, the problem of poor internal electrode lead-out caused by alignment error can be solved, thereby improving the product qualification rate.

[0019] Specifically, the preparation method of the capacitor includes the following steps:

[0020] S1: Place the ceramic film under the printing screen and use the alignment marker to adjust and confirm the printing position; ensure that the electrode slurry can be accurately printed on the predetermined position of the ceramic film. The alignment marker helps the operator to align the screen and the film to ensure the accuracy and consistency of the printed pattern;

[0021] S2: Print the electrode slurry on the ceramic film according to the pattern of the electrode pattern area through screen printing technology;

[0022] S3: Multiple printed ceramic films are staggered and stacked into a stack, and then laminated into blocks; through the stacking and lamination process, multiple printed ceramic films are fixed together to form the core structure of the MLCC capacitor. The staggered stacking is to ensure that the internal electrodes can be correctly alternately connected.

[0023] S4: Cut the block according to the cutting mark to obtain the inner electrode integral unit, and finally prepare the capacitor green body into MLCC capacitor.

[0024] Preferably, the inner electrode of the inner electrode integral unit described in S4 can extend beyond the end electrode wrapping portion to expand the creepage distance between the inner electrode and the end electrode. Sufficient creepage distance can prevent electrical breakdown and dielectric aging, thereby improving the electrical performance and service life of the capacitor.

[0025] Preferably, the stacking method in S3 includes stacking adjacent ceramic films with a staggered length of a first region or a second region along the X-axis. By staggered stacking, the effective capacitance of the capacitor can be increased because the inner electrodes on each layer of ceramic film are alternately connected to the inner electrodes of the adjacent layer, thereby increasing the interaction between the electrodes.

[0026] Preferably, the internal electrode integral unit includes a dummy electrode, and the existence of the dummy electrode allows the continuity of the internal electrode structure of the capacitor to be ensured through the extended portion of the internal electrode during the cutting process even if there is a slight alignment error.

[0027] Preferably, the capacitor is a high-voltage capacitor, and the stack in S3 includes eight ceramic films, ensuring that the capacitor green body is finally prepared into a high-voltage MLCC capacitor.

[0028] Compared with the prior art, the embodiments of the present invention have the following advantages and beneficial effects:

[0029] 1. The screen printing device for MLCC capacitors provided in an embodiment of the present invention can realize the printing of different graphics in the same screen printing process by setting a first area and a second area of ​​two different graphics on the printing screen, thereby avoiding the positioning error and dimensional consistency problems that may occur when using different screen devices to print different graphics. This structure allows the creepage distance between the end electrode and the inner electrode to increase, thereby reducing the risk of electric field distortion and spike discharge, and improving the reliability and safety of MLCC capacitors. Since the printing of two different graphics can be completed in one printing process, the production efficiency is improved, and the time and cost required for multiple printing and positioning are reduced. The device can meet the requirements of high-capacitance products with multiple layers and thin thickness of each layer, which helps to achieve higher performance MLCC products.

[0030] 2. The embodiments of the present invention can adapt to the specific requirements of the internal structure of the MLCC capacitor by designing patterns (b and a) of different lengths, such as increasing the creepage distance between the terminal electrode and the inner electrode, reducing the risk of electric field distortion and spike discharge. The design of b being greater than a ensures the wrapping width of the terminal electrode. At the same time, b is greater than the wrapping width of the terminal electrode, ensuring that the creepage distance between the terminal electrode and the inner electrode is sufficient, thereby improving the reliability of the capacitor, optimizing the electric field distribution inside the capacitor, reducing electric field distortion, and improving the electrical performance and reliability of the capacitor.

[0031] 3. The embodiment of the present invention aims at the problem that in the production process of MLCC capacitors, due to the presence of extremely small alignment errors in the lamination process of the electrode-covered film, this may lead to poor local internal electrode lead-out of some products after cutting, affecting the product qualification rate. An optimized solution is proposed, that is, the pattern with a length of b is not only limited to the first area, but also extends to the adjacent second area, and the length of the extension part is c. This structure ensures that during the cutting process, even if there is a slight alignment error, the continuity of the internal electrode structure of the capacitor can be ensured by the internal electrode of the extension part. There is a gap between the pattern with a length of b and the pattern in the second area, which helps to form virtual electrodes after cutting, that is, those electrode parts that are not directly connected to the external circuit but still have an impact on the performance of the capacitor. The existence of the virtual electrode can act as a buffer. Even if the main electrode is not fully formed due to the alignment error, the virtual electrode can guarantee the performance of the capacitor to a certain extent, reduce the waste caused by the alignment error, and thus improve the product qualification rate.

[0032] In general, the embodiments of the present invention increase the creepage distance between the terminal electrode and the internal electrode while ensuring consistency by setting the printing screen of the printing equipment to include a first area and a second area with two different patterns, thereby achieving the purpose of reducing the risk of electric field distortion and spike discharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0034] Figure 1 This is a diagram of an electrode structure prepared by printing with a screen device in the prior art;

[0035] Figure 2 Schematic diagram of increasing the creepage distance between the terminal electrode and the inner electrode after printing for different screen equipment;

[0036] Figure 3 An electrode structure diagram of a capacitor provided by an embodiment of the present invention;

[0037] Figure 4 A schematic diagram of the structure of a printing screen of a printing screen device provided in an embodiment of the present invention;

[0038] Figure 5 It is a schematic diagram of the printing screen structure of prior art 1;

[0039] Figure 6 It is a schematic diagram of the internal electrode structure of the capacitor in the prior art 1;

[0040] Figure 7 It is a schematic diagram of the printing screen structure of prior art 2, wherein Figure 7 a is one of the graphs, Figure 7 b is another graph;

[0041] Figure 8 It is a schematic diagram of the internal electrode structure of the capacitor in the prior art 2;

[0042] Fig. 9 A schematic diagram of the structure of a printing screen of a printing screen device provided in an embodiment of the present invention;

[0043] Fig.10 A structural diagram of a capacitor with poor electrode lead-out according to an embodiment of the present invention;

[0044] Fig.11 A schematic diagram of a printing screen structure optimization process provided by an embodiment of the present invention;

[0045] Fig.12 A schematic diagram of the structure of an optimized printing screen provided in an embodiment of the present invention;

[0046] Fig.13 A schematic diagram of the optimized inner electrode structure of a capacitor provided in an embodiment of the present invention.

[0047] Description of reference numerals:

[0048] 1-alignment mark point, 2-cutting line, 3-electrode pattern area, 4-first area, 5-second area. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0050] Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] An embodiment of the present invention provides a screen printing device for an MLCC capacitor, which can print two graphics at the same time and ensure size consistency, and integrates improvements in electrode structure, number of dielectric layers and various aspects of structure to better prevent spike discharge between the inner electrode and the terminal electrode of the capacitor.

[0052] For example, Figure 4 As shown, the screen printing equipment for MLCC capacitors mainly consists of three parts: alignment mark point 1 (alignment mark), cutting line 2 (cutting mark) and electrode pattern area 3. By designing the electrode pattern area, MLCC capacitors with different internal electrode structures can be realized.

[0053] Prior art 1 uses a screen printing device, in which the electrode pattern area of ​​the printing screen of the technology is a plurality of completely identical patterns, and the length of each pattern is a. Figure 5 The internal structure of the MLCC capacitor produced by the prior art 1 is shown in Figure 6 As shown, where d 1 is the terminal electrode wrapping width, f 1 is the creepage distance.

[0054] Prior art 2 is implemented using two screen printing devices. This technology designs the inner electrodes of two adjacent layers of MLCC capacitors into two patterns, one of which is entirely suspended electrodes with a length of a and no connection with the electrodes at both ends (the pattern does not cross the cutting line). Figure 7 a; another pattern has a pattern length b of the connection between the inner electrode and the two end electrodes, and the length of b is greater than a and greater than the wrapping width of the end electrode, see Figure 7b. The above two graphics are made into two sets of printing screen equipment, and the electrode membranes printed by these two sets of screens are stacked (without misalignment). After cutting, MLCC capacitors with increased electrode creepage spacing can be obtained. The internal electrode structure is as follows Figure 8 As shown, where d 2 is the terminal electrode wrapping width, f 2 is the creepage distance.

[0055] Back to the embodiment of the present invention, its feature is that the internal electrode patterns of two different products are integrated on the same printed screen and produced using the same screen printing equipment, thereby reducing the precision impact caused by switching screens and enabling the internal electrode to extend beyond the end electrode wrapping portion, thereby ensuring that the internal electrode and the end electrode of the product have a longer creepage distance. The printed screen pattern designed to achieve the above purpose is as follows Fig. 9 As shown, number 4 represents the first area and number 5 represents the second area, that is, the printed screen consists of a first area 4 of graphics and a second area 5 of graphics. The first area 4 contains 5 graphics, of which the leftmost and rightmost graphics have a length b and are used as internal electrodes to connect with the end electrodes (close to the cutting line), and the length of the three floating electrodes in the middle is a; the second area 5 contains 4 graphics, all of which are floating electrodes with a length a, and the length of b is greater than a and greater than the wrapping width of the end electrode.

[0056] use Fig. 9 The screen printing device shown in the figure prints the inner electrode. When stacking the films, the adjacent electrode films only need to be offset along the X-axis by the length of a graphic area. In theory, after cutting, the same capacitor inner electrode structure as that of the prior art 2 can be obtained (such as Figure 8 shown).

[0057] However, it was found during the test that due to the extremely small alignment error in the electrode-covered film stacking process, the cutting would cause the local internal electrode lead-out of some products to be poor, affecting the product qualification rate. Fig.10 As shown, point A shows the phenomenon of poor lead-out.

[0058] In order to deal with the above problems, the patented technology has been optimized and adjusted. The length of the pattern adjacent to the cutting line in the first area 4 of the pattern is extended to the second area 5 of the pattern, and the length of the crossing cutting line is c (about 100μm). The inner electrode of this length becomes the virtual electrode of the adjacent capacitor after cutting. In this way, the inner electrode structure of the capacitor of the patented technology is completely unaffected by the stacking film alignment accuracy. See Fig.11 As shown, the improved printing screen pattern of the embodiment of the present invention is shown in Fig.12 shown.

[0059] The inner electrode printed by the screen printing device provided by the embodiment of the present invention is stacked, and the adjacent electrode membranes are offset along the X-axis by the length of a graphic area, and after cutting, the following can be obtained: Fig.13 The internal structure of the capacitor is shown in Figure 1. 3 is the terminal electrode wrapping width, f 3 The capacitor produced by the printing device provided by the embodiment of the present invention has the characteristics of using a single wire mesh device to increase the creepage distance, and adds a virtual electrode, which can ensure that the inner electrode is 100% well led out after cutting without affecting the electrical performance.

[0060] In general, the present invention is an embodiment that integrates multiple product area graphics into the same printing screen, significantly improving production efficiency and ensuring high consistency of size between graphics. This design not only optimizes the electrical performance of the capacitor and improves production efficiency, but also greatly improves the product qualification rate, thereby significantly reducing production costs and enhancing market competitiveness.

[0061] During the specific operation, you can choose a screen of suitable material as the printing basis, and then use high-precision platemaking technology to accurately produce patterns including alignment marks, cutting lines and electrode patterns on the screen. Finally, the finished printing screen is quality checked to ensure graphic accuracy and screen integrity.

[0062] The printing device provided in the embodiment of the present invention is used to prepare an MLCC capacitor. For example, the MLCC capacitor contains eight high-voltage capacitors connected in series (such as Figure 3 Specific operation methods include:

[0063] (1) Place the ceramic film under the printing screen and align it;

[0064] (2) Using screen printing technology, the electrode slurry is accurately printed on the ceramic film according to the electrode pattern;

[0065] (3) using the cutting line area to accurately cut the printed ceramic film to form a laminate;

[0066] (4) The stacking machine automatically stacks the stacked bodies according to the recognition point pattern to complete the initial assembly of the capacitor.

[0067] This operation method utilizes the printing device provided by the embodiment of the present invention, and has broad application prospects in the field of electronic component manufacturing. As the performance requirements of electronic products for capacitors continue to increase, the high-precision and high-efficiency production characteristics of the embodiment of the present invention will make it a preferred solution in the industry. At the same time, the preparation method and use method of the device are simple and easy to implement, which is conducive to the rapid promotion and application of technology.

[0068] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A screen printing device for MLCC capacitors, comprising a printing screen, characterized in that: The printing screen comprises: Registration mark, set to adjust and confirm the printing position; Cutting markers to indicate where the ceramic film needs to be cut into individual MLCC units after printing; The electrode pattern area is configured to print an inner electrode pattern consistent with the pattern on the ceramic film when the electrode slurry is applied; The electrode pattern area includes a first area and a second area, and the pattern of the first area is different from the pattern of the second area.

2. The screen printing device for MLCC capacitors according to claim 1, characterized in that: The first area and the second area are arranged adjacent to each other in a transverse direction, the first area includes five transversely arranged patterns, the lengths of the two patterns on the left side and the right side are respectively b, and the lengths of the three patterns in the middle are respectively a; The second region includes four transversely arranged patterns, and the lengths of the four transversely arranged patterns in the second region are respectively a; The b is greater than a, and the b is greater than the wrapping width of the terminal electrode.

3. The screen printing device for MLCC capacitors according to claim 2, characterized in that: The pattern with a length of b is arranged to extend into the second region adjacent thereto, and its length in the second region is c; c is greater than zero, and there is a gap between the pattern with a length of b and the pattern in the second region.

4. The screen printing device for MLCC capacitors according to claim 3, characterized in that: 80μm>c>120μm.

5. A capacitor, characterized in that: The capacitor uses the screen printing device described in any one of claims 1 to 4 to print internal electrodes.

6. A method for preparing a capacitor as claimed in claim 5, characterized in that: The following steps are involved: S1: Place the ceramic film under the printing screen and use the alignment marker to adjust and confirm the printing position; S2: Print the electrode slurry on the ceramic film according to the pattern of the electrode pattern area through screen printing technology; S3: stacking the printed ceramic films into a stacked body in an offset manner, and then laminating them into a block; S4: Cut the block according to the cutting mark to obtain the inner electrode integral unit, and finally prepare the capacitor green body into MLCC capacitor.

7. The method for preparing a capacitor according to claim 6, characterized in that: The inner electrode of the inner electrode integral unit described in S4 can extend beyond the end electrode wrapping portion to expand the creepage distance between the inner electrode and the end electrode.

8. The method for preparing a capacitor according to claim 6, characterized in that: The stacking method in S3 includes stacking adjacent ceramic films by displacing them along the X-axis by a length of a first region or a second region.

9. The method for preparing a capacitor according to claim 7, characterized in that: The inner electrode integral unit includes a dummy electrode.

10. The method for preparing a capacitor according to claim 6, characterized in that: This capacitor is a high voltage capacitor, and the stack in S3 includes eight ceramic films.

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