TWI244749B - Over-current protection device and method for manufacturing its solder-resisting side - Google Patents

Abstract

The present invention discloses a method for manufacturing solder-resisting side of an over-current protection device, comprising the steps of providing a plate containing a plurality of current detection devices, forming grooves along opposite sides of the current detection devices of the plate, and then covering the plate with a screen printing steel plate on which openings are defined in correspondence to the grooves to allow printed solder-resisting substance to flow into the grooves to form uniform solder-resisting sides of the over-current protection device.

Description

1244749 IX. Description of the invention: [Technical field to which the invention belongs] θ The present invention relates to an overcurrent protection element and a method for manufacturing the same, and in particular, to an overcurrent protection element and a method for manufacturing an insulating side thereof. [Previous technology] ik aims at the wide application of uranium portable electronic products (such as mobile phones, notebook computers, mobile phones and personal digital assistants, etc.), in order to prevent the occurrence of electrical circuits (〇Ver_current) or excessive The use of over-temperature over-current protection devices is becoming more and more common. The purpose is not only to protect components from damage, but more importantly to protect the core circuits or batteries of electronic products from sudden improper power. · For example, the power supply has a sudden surge (wqe), which causes permanent damage to the components. The overcurrent protection element mainly includes a current sensing element, and the current sensing element usually includes a current sensing layer using a positive temperature coefficient polymer as a material, and thus is also referred to as a positive temperature coefficient polymer. siHve

Temperature Coefflcient (PPTC) element. The resistance value of this pPTc element is quite sensitive to the response to temperature changes. When the PPTC device is in normal use, its resistance can be kept very low, so that the circuit can operate normally. However, if the over-current or over-temperature phenomenon occurs and the temperature rises to a critical temperature, the resistance value will instantly jump to a high-resistance state (for example, more than 1040hm), and the excess current is reversely suppressed to achieve Purpose of protecting circuit components. Due to its current sensing and high polymer properties, this ppTC device has both overcurrent and overtemperature protection.

S8208 DOC 1244749 One of the known structures of the overcurrent protection element 10 is shown in Figure 丨, which includes a current sensing layer η, two internal electrode layers 12, two insulating layers 13, two = solder paint layers μ, and two external electrode layers.丨 5. The two internal electrode layers i 2 are disposed above and below the current sensing layer η to form a current sensing element 16 similar to a sandwich structure. Since the current sensing layer n includes a conductive pPTc material, the electric current sensing element 16 may also be referred to as a PPTC element. The insulating layer 13 is respectively disposed on the current sensing element 16 and on the surface of τ for heat conduction and insulation. The solder resist lacquer layer M and the external electrode layer 15 are provided on the surface of the insulating layer 13 and are used as solder resist and adhesion when soldering to an external circuit board, respectively. The side of the overcurrent protection element ii) has a semi-cylindrical conductive hole 17 for conducting the upper and lower external electrode layers 15 and the internal electrode layers 12 ', which can be electroplated or coated with a conductive paste for electrical conduction. 2. The overcurrent protection element 10 is covered with a solder resist paint layer on top and bottom of the overcurrent protection element _ in order to ensure 5 '' on both sides of it also need to respect and do not shun 'to cover the protective material, called the insulation side Side 'in order to isolate the side of the overcurrent protection element 10 from the adverse effects of the outside world, especially the oxidation caused by the infiltration of external water vapor and oxygen molecules, resulting in the reliability of the overcurrent protection ㈣1G becoming worse, While reducing its product life time. The conventional manufacturing method of the insulating side is to immerse the overcurrent protection ㈣10 in a solder resist. 'In order to expose the solder resist part, a masklng step must be added in the manufacturing process to make it unnecessary. Part is covered. Moreover, the immersed conventional technology uses a solder resist to cover the insulating side. Because the covering process requires appropriate process conditions to control the uniformity of the solder resist, the manufacturing method of the insulating side becomes more complicated. And

88208.DOC 1244749 Thickness of insulation side. In addition, the conventional system is only equivalent to the overcurrent protection element half of the full-surface seven-phase type, and the medium α ^ also limits its application. [Summary of the Invention] * In order to have the above-mentioned disadvantages, the present invention provides a simplified punching method. Screen printing is performed by brushing the side insulation material in a panel including a plurality of peach-covered sensing elements. The invention discloses a method for manufacturing an insulating side of an overcurrent protection element; the steps are to provide a panel including a plurality of current sensing elements. A plurality of current sensing elements are arranged in an array, and-trenches are provided between adjacent columns. Next, a screen-printed steel plate is covered on the panel, and the position of the printed steel plate relative to the groove is-corresponding to the opening. After that, the ^ I 'material on the screen-printed steel sheet' flows the brushed insulation material into the groove ... and makes the insulation material formed on the side of the current sensing element opposite to the groove 'to form a uniform hook. Overcurrent protection element on the insulation side. 3 The difference compared with the conventional technique is that the present invention particularly applies screen printing to brush the insulating material on the panel, and uniformly brushes the insulating material through the opening grooves of the panel and covers the current sensing elements. The insulation side can be achieved, and the thickness of the insulation side can be effectively controlled. Further advantages can be seen in the following embodiments, which are elastic to electrodes other than the overcurrent protection element. [Embodiment] FIG. 2 illustrates a king diagram of a manufacturing method of an insulating side of the overcurrent protection element of the present invention. First, a panel including a plurality of current sensing elements is provided.

88208.DOC 1244749 (plate), the 忒 current sensing element is a half-button of an overcurrent protection element that is nearly completed, and includes at least one pPTc element, a plurality of insulating layers, and two external electrode layers. The PPTC device includes a current-sensing interlayer with a conductive positive temperature coefficient polymer and two internal electrode layers stacked on the upper and lower surfaces of the current-sensing interlayer. The plurality of insulating layers are respectively stacked on the upper and lower surfaces of each of the PPTC elements. The two external electrode layers are respectively stacked on two ends of the outer surface of the plurality of insulating layers to form two ends of the electrodes, and the upper and lower external electrode layers of the two ends of the current sensing element are electrically conductive with a conductive object Connected. The conductive object can be a metal foil as a side electrode at both ends, or a conductive hole. The motor sensing element is electrically connected to the PPTC element through the external electrode layer, and is welded to a pad of an external circuit board to form a semi-finished product of an electrically conducting overcurrent protection element. Opening grooves are formed on the two insulating sides of each current sensing element of the panel to make insulating sides. In the next step, a screen-printed steel plate is covered above the panel. The screen-printed steel plate has all holes in the groove to expose the insulated sides of each current sensing element, but the screen-printed steel plate must be held Conductive metal parts, such as external electrode layers. After that, the insulating material is printed on the opening groove of the screen-printed steel plate, so that the insulating material flows into the groove. Because the design of the opening width of the groove must consider the insulating material used and the tools used for printing, the purpose is to uniformly print an insulating side. Therefore, the present invention does not limit the position, geometry, and size of the opening groove], nor does it limit the insulating materials used, and the tools and methods used during printing. Fig. 3 does not show the panel 30 including a plurality of current sensing elements and the corresponding screen-printed steel plate 35. The panel 30 includes a plurality of electric cells arranged in a matrix manner.

88208.DOC 1244749 Flu detection element 32 and a plurality of grooves 3 丨. The plurality of trenches 3 丨 divide the plurality of current sensing elements 32 arranged in the matrix into a plurality of rows, and the insulating sides of each of the electrical sensing elements 32 face the trenches 3 丨. The common side edge 3 4 of the adjacent current sensing elements 32 includes a circular hole 3 3, and the inner edge of the circular hole 3 3 has a plating layer for electrically conducting the upper and lower outer electrode layers. The screen-printed steel plate 3 5 has a plurality of openings 3 6 corresponding to the groove clear 31. After the panel 30 has completed the manufacturing process of the insulating side of FIG. 2, the manufacturing personnel can share the side w as a cutting line and cut the panel 30 into a plurality of overcurrent protection elements. The two sides of the two outer electrodes of the overcurrent protection element each have a semi-cylindrical conductive hole. The semi-cylindrical conductive hole is cut in half by a circular hole 33. The present invention does not limit the size and position of the diameter of the circular hole 33, and its different implementation modes are as described in the following embodiments. Referring to FIG. 3, the insulating material flows into the plurality of grooves 31 through a plurality of corresponding openings 36 of the screen-printed steel plate 35, and the solder-proof material is evenly covered with the insulation of each overcurrent protection element through an appropriate screen printing process Side. In addition to the fast production speed, the thickness of the insulating side can also be effectively controlled. 4 (a) and 4 (b) show different embodiments of the above-mentioned circular hole 33. Fig. 4 (a) is a semi-cylindrical conductive hole 44, and its embodiment is directly cut from Fig. 3 through a cutting line. The overcurrent protection element 40 includes two external electrode layers 41, two insulating layers 42, two insulating sides 43, and two semi-cylindrical conductive holes 44. The two insulating sides 43 are obtained according to the manufacturing process shown in FIG. 2 of the present invention. 4 (b) is a full-cylindrical conductive hole 4 5. The method of applying it is to move the circular hole on the cutting line of FIG. 3 to the inside of the outer electrode layer, so the circular hole plating material after cutting will not be exposed.

88208.DOC 1244749 FIG. 5 shows another embodiment of the present invention. In this embodiment, after the above-mentioned side insulation manufacturing process is completed, an outer layer electrode 51 is manufactured. The overcurrent protection element 50 shown in the figure includes two external electrode layers 51, two insulating layers 52, two insulating side edges 53 and two semi-cylindrical conductive holes 54. The manufacturing method of the two external electrode layers 5 丨 can cut the panel 3 of the plurality of overcurrent protection elements shown in FIG. 3 into a plurality of overcurrent protection elements 32 along the cutting line, and then each of the overcurrent protection elements 32 is barrel-plated. The electrical conduction part is electroplated into two external electrode layers. The overcurrent protection element 50 can be applied to a larger-sized circuit board assembly, such as an element having an aspect ratio of 1206, 0805. However, for smaller-sized circuit board assembly, such as 0402 or less, in order to avoid excessive short circuit caused by electrical short circuit, it is still better to use overcurrent protection components 40. This embodiment only uses the overcurrent protection element 50 of the semi-cylindrical conductive hole 54 as an implementation aspect, but the description does not limit the scope of the present invention. For example, the outer electrode layer 51 may have a full surface ( full_face), without any conductive holes in the external electrode layer 51. The technical content and technical features of the present invention have been disclosed as above. However, those skilled in the art may still make various substitutions and modifications based on the teaching and disclosure of the present invention without departing from the spirit of the present invention. Therefore, the protection scope of the present invention should not be limited to those disclosed in the embodiments, but should include various substitutions and modifications that do not depart from the present invention, and should be covered by the following patent application scope. [Brief description of the drawings] FIG. 1 is a schematic diagram of an overcurrent protection element of the conventional art; FIG. 2 is a manufacturing flow chart of the present invention; FIG. 3 is a panel including a plurality of current sensing elements of the present invention and an assembly thereof

88208.DOC -10- 1244749 The schematic diagram of the screen-printed steel sheet; the current protection element Figure 4 (a) is a perspective view of the passing part of the semi-cylindrical conductive hole made in the present invention; Figure 4 (b) is the present invention A perspective view of the component; and a perspective view of another embodiment of the over-current protection element protecting element made of a full cylindrical conductive hole. Figure 5 shows the overcurrent protection of the present invention. [Element symbol description] 10 Overcurrent protection element 12 Internal electrode layer 14 Solder resist paint layer 16 Current sensing element 31 Groove 33 Round hole 3 5 Screen-printed steel plate 40 Overcurrent protection element 42 Thermally conductive insulating layer 44 Semi-cylindrical conductive hole 5 0 Overcurrent protection element 52 Thermally conductive insulating layer 54 Semi-cylindrical conductive hole 11 Current sensing layer 13 Insulating layer 15 External electrode layer 17 Semi-cylindrical conductive hole 32 Over-current protection element 34 Common side 36 Opening 41 External electrode layer 43 Insulation side 45 Full cylindrical conductive hole 51 External electrode layer 53 Insulation side

88208.DOC

Claims (1)

1244749 Ten declared patent scope: 1. An overcurrent protection element, comprising:-a positive temperature coefficient polymer element, including a current sensing loss layer and two internal electrode layers; to J-an insulating layer, provided at the positive temperature coefficient polymerization Surface of the object element · At least one external electrode layer provided on the surface of the insulating layer; at least one conductive hole penetrating the insulating layer and used to electrically connect the internal electrode layer and the external electrode layer; and at least one insulating side The edge is formed on one side of the positive temperature coefficient polymer element. 2. The overcurrent protection element according to the item}, wherein the conductive hole is a semi-cylindrical conductive hole. 3. According to the overcurrent protection element of the request item, the conductive hole in # is a fully conductive hole. 4. A method for manufacturing an insulating side of an overcurrent protection element, comprising the following steps: / a panel, wherein a groove is provided between the plurality and adjacent columns to provide a plurality of current sensing element systems including a plurality of current sensing elements The grooves are arranged in an array; a cover is printed with a corresponding opening at the position of the groove; and a printing-insulating material is printed on the screen-printed steel plate, and the insulating material is formed on the current sensing element. Opposite the side of the groove. 5 · The manufacturing method of over-current protection element according to claim 4 is 1245349, the impedance of the edge material is greater than 10MΩ. 6. The manufacturing method of the insulating side of the overcurrent protection element according to claim 4, further comprising the step of enclosing the two outer φ electrode layers in the surface of the plurality of current sensing elements. 7. The insulation side of the overcurrent protection element according to claim 6, wherein the plating of the external electrode layer is performed by barrel plating. Method, 88208.DOC