Chip zinc oxide piezoresistor

Abstract

The utility model discloses a surface-mounted zinc oxide varistor which comprises a voltage-sensitive ceramic chip, surface electrodes and side electrodes positioned on the upper side and the lower side or the lower side of the surface electrodes are arranged on bosses at the two ends of the voltage-sensitive ceramic chip along the length direction, and the side electrodes are used for adhering and positioning solder paste during reflow soldering, can be horizontally laid on a PCB (Printed Circuit Board) and are prevented from rolling. According to the utility model, the bosses at the two ends of the pressure-sensitive ceramic chip increase the distance between the side electrodes and different side surface electrodes to exceed the shortest distance between the two surface electrodes, so that the problems of short distance and pressure-sensitive voltage drop caused by the side electrodes are avoided; and the pressure-sensitive ceramic chip is provided with a boss height interval when being welded on the PCB so as to prevent solder paste from polluting the ceramic body at the lower side edge.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of pressure sensitive resistance, more particularly to a patch zinc oxide pressure sensitive resistor. BACKGROUND

[0002] At present, most of the lighting devices adopt LED lamp beads, which have relatively poor resistance to surge impact in the circuit and need to be surge protected; due to the conductivity of the heat dissipation aluminum substrate, plug-in components are not suitable, and the surge protection varistors currently in use all adopt patch packaging, which is convenient for mass production of LED lamp heads.

[0003] However, in the prior art, Chinese patents CN202211338129.4, CN201610472205.9, CN201510955379.6 and CN201010580937.2 disclose a multilayer varistor and a manufacturing method thereof, which adopts a multilayer ceramic capacitor process, uses a flow casting machine to flow cast, prints an internal electrode, isostatic pressed, laminated and cut, pre-applies glue, atmosphere sintering, electrode connection, nickel plating and tin plating processes, on the one hand, the production equipment investment is large, and the equipment requirement is high, on the other hand, due to the thickness limitation between layers, it is suitable for voltage protection of 5V-100V rated voltage, and finally, when a surge impact occurs, due to the multilayer structure, uneven heat can easily cause crack failure;

[0004] For example, Chinese patent CN202010966184.2 discloses a traditional plug-in assembly, coating flattening treatment and horizontal patching scheme; Chinese patent CN201820356800.0 discloses a matrix type varistor patch packaging scheme, and Chinese patent CN201711165632.3 discloses an embedded varistor flat patch packaging scheme, all of which use traditional varistor chips, and after welding through leads or frames, the surface electrode is parallel to the PCB board, and flat packaging is achieved SMD patching, but the structure is relatively complex, the consistency of the lead processing size is poor, the production control is difficult, and the chip flat packaging occupies more PCB board area;

[0005] For example, Chinese patent CN201822145675.1 discloses a series structure varistor patch scheme, which adopts a two-varistor series connection method, but the distance between the two varistors is small, which is easy to cause air breakdown, thereby limiting the application of the product.

[0006] Therefore, it is an urgent problem for those skilled in the art to provide a patch zinc oxide varistor. Utility model content

[0007] Therefore, the utility model provides a patch zinc oxide varistor, which has the advantages of simple structure, small size, good heat dissipation, good lightning pulse resistance, and low production cost.

[0008] To achieve the above object, the utility model discloses the following technical scheme:

[0009] A patch zinc oxide pressure resistor, including pressure sensitive porcelain piece, the pressure sensitive porcelain piece is equipped with the surface electrode and the side electrode on the boss of both ends along the length direction upper and lower sides or lower side of surface electrode.

[0010] By adopting the above technical scheme, the utility model has the beneficial effects:

[0011] 1) the distance of side electrode and different side surface electrode is increased to the boss of both ends of pressure sensitive porcelain piece, and the shortest distance between two surface electrodes is exceeded, so that the problem of short distance and pressure sensitive voltage drop caused by side electrode is avoided;

[0012] 2) the pressure sensitive porcelain piece has boss height interval when being welded on the PCB board, so that the pollution of tin paste to the lower side porcelain body is avoided;

[0013] 3) the side electrode is used for tin paste adhesion positioning when reflow soldering, and can lie on the PCB board, and rolling is prevented.

[0014] Further, the surface electrode and the side electrode are arranged on the boss by printing, rolling or transfer printing.

[0015] Further, the length of the pressure sensitive porcelain piece is 3-8mm.

[0016] The beneficial effects of the above further technical scheme are that the fixed length is convenient for PCB pad layout.

[0017] Further, the boss is provided with a metal sheet or a metal sleeve or a metal ring.

[0018] The beneficial effects of the above further technical scheme are that the current can be balanced when surge impact, the elasticity of pad connection can be increased, and it is suitable for high temperature difference environment.

[0019] Further, the main body of the pressure sensitive porcelain piece is coated with an insulating layer.

[0020] Further, the protruding height of the boss is 0.1-1mm. DRAWINGS

[0021] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the drawings needed to be used in the embodiment or the prior art description will be briefly introduced below, and obviously, the drawings in the following description are only the embodiments of the utility model, and those skilled in the art can obtain other drawings according to the provided drawings without creating creative labor.

[0022] Figure 1 Figure is a front view of a patch zinc oxide varistor of Example 1;

[0023] Figure 2 Figure is a top view of a patch zinc oxide varistor of Example 1;

[0024] Figure 3 Figure is a side view of a patch zinc oxide varistor of Example 1;

[0025] Figure 4 Figure is a front view of a patch zinc oxide varistor of Example 2;

[0026] Figure 5 Figure is a top view of a patch zinc oxide varistor of Example 2;

[0027] Figure 6 Figure is a side view of a patch zinc oxide varistor of Example 2;

[0028] Figure 7 Figure is a front view of a patch zinc oxide varistor of Example 3;

[0029] Figure 8 Figure is a top view of a patch zinc oxide varistor of Example 3;

[0030] Figure 9 Figure is a side view of a patch zinc oxide varistor of Example 3. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0032] Example 1:

[0033] As Figures 1-3The utility model discloses a kind of patch zinc oxide varistors, including pressure-sensitive porcelain piece 1, pressure-sensitive porcelain piece 1 overall is similar to cuboid, it is beneficial to suction nozzle suction and prevent rolling when patch, pressure-sensitive porcelain piece 1 length is 3-8mm, fixed length, it is convenient for PCB board 2 welding point layout, in the embodiment, PCB board 2 protective circuit lead spacing commonly used is 3mm, 5mm, considering printing tin point size, then pressure-sensitive porcelain piece 1 length exceeds the center distance of welding point, can be set to 3.5, 5.5mm, so as to facilitate tin paste point adhesion, pressure-sensitive porcelain piece 1 both ends boss along length direction are equipped with surface electrode 3 and the side electrode 4 located in the upper and lower sides of surface electrode 3, in the embodiment, boss cross section is similar to isosceles trapezoidal shape, boss outside is chamfered, boss protruding height is 0.1-1mm, surface electrode 3 minimum face projection area is between 1.5-30mm 2 Wherein side electrode 4 is used for tin paste adhesion positioning when reflow soldering, can lie on PCB board 2, prevent rolling.The utility model pressure-sensitive porcelain piece 1 both ends boss increase the distance of side electrode 4 and different side surface electrode 3, to exceed the shortest distance between two surface electrodes 3, avoid side electrode 4 to cause distance short, varistor voltage drop problem, and pressure-sensitive porcelain piece 1 has boss height interval when being welded on PCB board 2, to avoid tin paste pollution to downside edge porcelain body.

[0034] In order to further optimize the technical scheme of the utility model, a metal sheet or a metal sleeve or a metal ring is arranged on the boss, which can balance the current during surge impact, increase the elasticity of the welding point connection, and be suitable for high-temperature difference environments.

[0035] The production method of the utility model comprises the following steps:

[0036] 1) configure powder: configure low-gradient zinc oxide powder; in the embodiment, prepare gradient G=140V / mm powder; take ZnO, Bi2O3, Co3O4, Sb2O3, MnCO3, Ni2O3, B2O3, CuO, Al2O3 powder, and the molar percentage of each component is: 90-95.5%: 4-5.8%: 0.2-0.3%: 0.2-0.4%: 0.2-0.4%: 0.35-0.45%: 0.05-0.2%: 0.010-0.03%: 0.005%-0.01%; grind Bi2O3, Co3O4, Sb2O3, MnCO3, Ni2O3, B2O3, CuO, Al2O3 powder, grind the mixture after grinding, and grind the mixture after grinding and ZnO, spray drying after adding glue to prepare zinc oxide pressure-sensitive porcelain powder;

[0037] 2) pressing green body: using a mold with a pre-prepared convex to press a cuboid green body piece; in this embodiment, the mold with a pre-prepared convex has a size of 4.2x2.9, R0.1mm, and the pressed green body piece has a thickness of 2.9mm, and the pressing piece density E is 3.4g / cm 3 ;

[0038] 3) glue removal and sintering: pre-removing glue of the green body piece and then sintering to form the pressure-sensitive porcelain piece 1; in this embodiment, pre-removing glue for 3 hours at 560° in a muffle furnace, and then sintering for 4.5 hours at 1185° to obtain the pressure-sensitive porcelain piece 1 with a size of 2.5x2.5x3.5mm;

[0039] 4) making the surface electrode 3 and the side electrode 4: taking 80% silver paste, respectively transferring 2.0x2.5 electrodes on the outer surfaces of the two convexes of the pressure-sensitive porcelain piece 1 to form the surface electrode 3 with a length and width of 2.0x2.0 and the side electrode 4 with a length and width of 2.0x0.25; after drying, burning silver in a silver burning furnace to form the surface electrode 3 on the convex body and the side electrode 4 on the convex R angle side.

[0040] Measuring the three parameters of the sample before and after the surge impact, as shown in the following table:

[0041] Series 4.7 ohms, surge pulse 1KV / 500A+AC220V, 0, 90, 180, 270° 4 phases each ±5 times.

[0042]

[0043] Embodiment 2:

[0044] As Figures 4-6 shown, the utility model discloses a kind of patch zinc oxide varistor, and the difference from embodiment 1 is that insulating layer 5 is coated on the main body of pressure-sensitive porcelain piece 1.

[0045] The production method of the utility model, and the difference from embodiment 1 is that: step 3) glue removal and sintering are pre-removed glue for 3 hours at 560° in a muffle furnace, and then sintering for 4.5 hours at 1125°;After step 4), product is positioned after shaking plate, and epoxy resin is coated, and insulating layer 5 is formed after solidification.

[0046] Measuring the three parameters of the sample before and after the impact, as shown in the following table:

[0047] Series 4.7 ohms, surge pulse 1KV / 500A+AC220V, 0, 90, 180, 270° 4 phases each ±5 times.

[0048]

[0049]

[0050] Embodiment 3:

[0051] As shown in Figures 7-9 The utility model discloses a kind of patch zinc oxide pressure sensitive resistors, and the difference from embodiment 1 is that: the two ends boss of pressure sensitive porcelain piece 1 along length direction are equipped with surface electrode 3 and the side electrode 4 located in the lower side of surface electrode 3, i.e. pressure sensitive porcelain piece 1 top plane is flat, only in bottom plane has similar trapezoidal recess, boss cross section is similar to isosceles trapezoidal shape.

[0052] Each embodiment in the specification is described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between each embodiment can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the method part.

[0053] The above description of the disclosed embodiments enables those skilled in the art to implement or use the utility model. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the utility model. Therefore, the utility model will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A patch zinc oxide varistor comprising a varistor ceramic, characterized in that The piezoelectric ceramic sheet is provided with a surface electrode and a side electrode on the upper side or lower side of the surface electrode on the boss at the two ends of the length direction.

2. The patch zinc oxide varistor of claim 1, wherein, The piezoelectric ceramic sheet has a length of 3-8 mm.

3. The patch ZnO varistor of claim 1, wherein, The boss is provided with a metal sheet or a metal sleeve or a metal ring.

4. The patch ZnO varistor of claim 1, wherein, The piezoelectric ceramic sheet is coated with an insulating layer on the main body.

5. The patch ZnO varistor of claim 1, wherein, The boss has a protruding height of 0.1-1 mm.

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