KR102486920B1 - Method for manufacturing protection device for open mode - Google Patents

Abstract

A manufacturing method of an open mode protection device is provided. A method of manufacturing an open-mode protection device according to an embodiment of the present invention is a method of manufacturing an open-mode protection device connected in parallel to a constant current source and a load composed of LEDs, wherein electrodes are formed on both sides of a large-area PPTC (polymeric positive temperature coefficient coefficient). ) forming slits on the substrate at regular intervals; mounting protective devices for bypassing overvoltage or overcurrent on electrodes with slits therebetween at regular intervals; molding with a molding member to cover the upper side of the large-area PPTC substrate and the protection element; and cutting the molded large-area PPTC substrate into unit elements including one protection element.

Description

Manufacturing method of open mode protection device {Method for manufacturing protection device for open mode}

The present invention relates to a method for manufacturing an open-mode protection device, and more particularly, to a method for manufacturing an open-mode protection device capable of simultaneously implementing a function of suppressing abnormal overheating and a high breakdown voltage of the protection device.

Recently, lighting devices using LEDs, which have high power efficiency and are easy to control, are becoming common. In particular, its use is rapidly increasing in fields such as backlights of display devices, various lamps of automobiles, and smart lighting using dimming.

These LED lights are provided with a constant current type lighting circuit that provides a constant current to a load made of LEDs. Here, a protection device is provided to protect a circuit when ESD (ElectroStatic Discharge), EOS (Electrical over stress), or surge flows between the constant current source and the load.

In such a constant current type electronic device, when one of the LEDs is damaged by an electric shock and the load is in an open state, all the current of the constant current source flows to the protection device, and at this time, the protection device continuously rises and overheats. If excessive, it may ignite and cause a fire.

Therefore, there is an urgent need to develop a technology capable of suppressing overheating of the protection device according to the open mode of the load together with the ESD, EOS, or surge protection function for the LED load.

In addition, these protection devices require various withstand voltages depending on the application to which they are applied, and in particular, the development of protection devices having high withstand voltages is required.

KR 1005199 B (2010.12.24 Enrollment)

The present invention has been devised in consideration of the above points, and open-mode protection capable of simultaneously realizing a function of suppressing abnormal overheating of the protection device according to the open-mode operation of the load and a high withstand voltage to withstand high pressure by dividing and arranging the PPTC device. Its purpose is to provide a method for manufacturing a device.

In order to solve the above problems, the present invention provides a method of manufacturing an open mode protection device connected in parallel to a constant current source and a load including LEDs. The method of manufacturing the open mode protection device includes forming slits at regular intervals in a large-area polymeric positive temperature coefficient (PPTC) substrate having electrodes formed on both sides thereof; mounting protection devices for bypassing overvoltage or overcurrent on the electrodes with the slit therebetween at regular intervals; molding with a molding member to cover the upper side of the large-area PPTC substrate and the protection element; and cutting the molded large-area PPTC substrate into unit elements including one protection element.

According to a preferred embodiment of the present invention, the molding may fill the slit with the molding member.

In this case, the molding member may be made of epoxy.

In addition, in the molding, the epoxy sheet may be pressed and heat-sealed on the upper side of the large-area PPTC substrate.

In addition, the manufacturing method of the open mode protection device may further include plating an electrode on a lower surface of the large-area PPTC substrate after the molding.

At this time, in the plating step, the lower surface electrode of the large-area PPTC substrate may be plated with one of Ag, Pt, Sn, Cr, Al, Zn, and Au.

In addition, the double-sided electrodes of the large-area PPTC substrate may be formed by Ni or Cu plating.

In the forming of the slits, the size of the predetermined interval may be determined according to the cutting accuracy of the cutting.

In addition, the protection device may be any one of a varistor, a suppressor, a gas discharge tube (GDT), and a diode.

In addition, in the mounting step, the protection device may be mounted on the large-area PPTC board through an SMT soldering process.

In addition, the large-area PPTC substrate may be formed of a polymer layer in which a conductive filler is dispersed.

In this case, the conductive filler may be made of a carbon black material.

According to the present invention, by forming a slit in a large-area PPTC substrate and mounting the protection device with the slit therebetween, the function of suppressing abnormal overheating of the protection device and a high breakdown voltage can be implemented at the same time, so that the temperature or current of the protection device increases. While suppressing and thus preventing damage to the protection element itself due to abnormal overheating, it is not necessary to increase the thickness of the material to increase the withstand voltage, so thinning can be realized.

In addition, by filling the molding member in the slit of the large-area PPTC substrate, the present invention can improve the deterioration of strength due to the slit and at the same time improve the bonding force between the PPTC substrate and the protection element in the unit device, thereby improving product reliability. can make it

In addition, the present invention forms a slit on a large-area PPTC substrate to mount the protection element, so that mass production is possible and the size of the product can be easily adjusted, thereby providing flexibility in standardization.

In addition, the present invention can improve manufacturing efficiency by mounting a conventional protection device on a large-area PPTC substrate, thereby facilitating the design and arrangement of a large-area PPTC substrate according to the use of an existing product.

1 is a flowchart of a method of manufacturing an open mode protection device according to an embodiment of the present invention;
2 is a perspective view showing a state in which slits are formed in a large-area substrate;
3 and 4 are perspective and cross-sectional views showing a state in which a thin protection device is mounted;
5 is a perspective view showing a state before molding by an epoxy sheet;
6 and 7 are perspective and cross-sectional views showing a molded state by pressing and heat-sealing the epoxy sheet;
8 and 9 are perspective and cross-sectional views showing positions where the molded large-area substrate is cut;
10 is a cross-sectional view of a unit device manufactured by a method of manufacturing an open mode protection device according to an embodiment of the present invention;
FIG. 11 is an equivalent circuit diagram of the open mode protection device of FIG. 10 .

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. This invention may be embodied in many different forms and is not limited to the embodiments set forth herein. In order to clearly describe the present invention in the drawings, parts irrelevant to the description are omitted, and the same reference numerals are added to the same or similar components throughout the specification.

As shown in FIG. 1, the method 10 of manufacturing an open mode protection device according to an embodiment of the present invention includes forming a slit on a substrate (S101), mounting a protection device (S102), and epoxy molding. (S103), and cutting into unit elements (S105).

Here, the open mode protection device manufactured by the manufacturing method 10 includes a constant current source and a load by being connected in parallel to a constant current source and a load composed of LEDs and bypassing ESD, EOS or surge current flowing from the outside to the ground. This is to protect the circuit that

First, as shown in FIG. 2 , slits 116 are formed at regular intervals on a large-area polymeric positive temperature coefficient (PPTC) substrate 110a having electrodes 112 and 114 formed on both sides (step S101).

At this time, the slits 116 may be formed at regular intervals corresponding to the space required to cut the large-area PPTC substrate 110a into unit devices. That is, the size of the interval for arranging the slits 116 may be determined according to the precision of the cutting in the cutting step (S105), for example, the precision of the cutting mechanism.

Here, the electrodes 112 and 114 formed on both sides of the large-area PPTC substrate 110a may be prepared in advance. For example, the double-sided electrodes 112 and 114 may be formed in advance by Ni or Cu plating. At this time, in order to improve the adhesiveness of the Cu surface, any one of Fe, Ni, Cr and Ag may be additionally plated.

In addition, in the large-area PPTC substrate 110a, a base layer between the electrodes 112 and 114 may be made of a PPTC material. For example, the base layer may be formed of a polymer layer in which a conductive filler is dispersed. In this case, the conductive filler may be made of a carbon black material.

Here, the withstand voltage of the PPTC element formed by the large-area PPTC substrate 110a increases according to its thickness. That is, the withstand voltage of the PPTC element increases as the distance between the top electrode 112 and the bottom electrode 114 increases. Therefore, in order to apply the PPTC element to the backlight (BLU) of a display device such as a TV that requires a high withstand voltage, the gap between the top electrode 112 and the bottom electrode 114 must be large, but this is resulting in an increase in overall thickness.

Therefore, in the open mode protection device manufacturing method 10 according to an embodiment of the present invention, in order to realize thinning without increasing the thickness of the open mode protection device, the PPTC devices are spaced apart on the same plane and arranged on a large-area PPTC substrate. A slit 116 may be formed in 110a. That is, in the finally calculated unit element, since a pair of PPTC elements are arranged on the same plane, an increase in thickness is suppressed, and at the same time, since they are electrically arranged in series on both sides around the protective element, two Since the PPTC elements are arranged in series, it is possible to increase the breakdown voltage as a result.

Next, as shown in FIG. 3, protection elements 120 for bypassing overvoltage or overcurrent are mounted on the top electrode 112 with the slit 116 therebetween at regular intervals (step S102). Here, the protection device 120 may be disposed so that the slit 116 is located at a substantially central portion from the lower portion of the protection device 120 (see FIG. 4 ).

At this time, the protection device 120 may be mounted on the upper surface electrode 112 of the large-area PPTC substrate 110a through the SMT soldering process. That is, the protection device 120 may be connected to the top electrode 112 of the large-area PPTC substrate 110a through solder.

Here, the protection elements 120 may be spaced apart from each other at regular intervals to secure a space required for cutting the large-area PPTC substrate 110a into unit elements, similar to the spacing at which the slits 116 are arranged. That is, it is possible to determine the size of the interval for disposing the protection device 120 according to the precision of the cutting mechanism.

In this way, by forming the slit 116 on the large-area PPTC substrate 110a and mounting the protection device 120, mass production is possible and the interval at which the slit 116 is formed or the protection device 120 is disposed Since the size of the product can be easily adjusted according to the size, it can flexibly cope with various standards.

Here, the protection device 120 may be a pre-manufactured single component. As an example, the protection device 120 may be any one of a varistor, a suppressor, a gas discharge tube (GDT), and a diode, but is not particularly limited thereto, and may bypass overvoltage or overcurrent. may contain elements.

Through this, since a conventional single component is mounted on a pair of large-area PPTC substrates 110a, the manufacturing process can be simplified, and PPTC elements can be easily designed and arranged according to existing products, thereby increasing manufacturing efficiency. can improve

Meanwhile, the protection element 120 may include a varistor material layer. That is, the body of the protection element 120 may be made of a varistor material.

As another example, the body 120a of the protection device 120 may be made of a small body. Here, the body includes at least one of ZnO, BaTiO ₃ , and SrTiO ₃ , and Pr, Bi, Ni, Mn, Cr, Co, Sb, Nd, Si, Ca, La, Mg, Al, Ti Sn, Nb, and At least one of Y may be included as a dopant.

Next, molding is performed with a molding member so as to cover the upper side of the large-area PPTC substrate 110a and the protection element 120 (step S103). In this case, the molding member may be made of epoxy.

For example, as shown in FIG. 5, an epoxy sheet 130a is disposed on the upper side of the large area PPTC substrate 110a on which the protection device 120 is mounted, and heat-sealed while pressing it toward the large area PPTC substrate 110a. can

Through this, the molding member 130' melted by heat can be molded so as to completely cover the upper side of the large-area PPTC substrate 110a and the protection element 120 (see FIG. 6).

At this time, the slit 116, which is a space between the large-area PPTC substrates 110a at the lower side of the protection element 120, may be filled with the molding member 130' melted by the heat (see FIG. 7).

That is, the molding member 130' melted by the heat flows from the upper side of the large-area PPTC substrate 110a to the slit 116 disposed between the protection elements 120, and the lower side of the plurality of protection elements 120. It spreads throughout the slit 116 where it is placed. Accordingly, in the unit device, the space 102 between the pair of PPTC substrates 110 may be filled with a molding member (see FIG. 10).

Through this, in the open mode protection device 100, the strength between the pair of PPTC substrates 110 spaced apart from each other by the space portion 102 corresponding to the slit 116 can be supplemented.

That is, since the pair of PPTC substrates 110 are spaced apart from each other by the slit 116, bonding strength between the PPTC substrates 110 or between the protective element 120 may be weakened, and thus the pair of PPTC substrates 110 may be weakened. By filling the space portion 102 corresponding to the slit 116 disposed between the PPTC substrates 110 with a molding member, bonding strength may be improved.

Furthermore, by preventing exposure of the protection device 120 between the pair of large-area PPTC substrates 110a, the protection device 120 can be safely protected from external force.

Here, it has been described that the large-area PPTC substrate 110a and the protection element 120 are molded by pressurizing and heat-sealing the epoxy sheet 130a, but it is not limited thereto and it is revealed that molding can be performed with various molding members and molding methods. put

Next, the molded large-area PPTC substrate 110a is cut into unit elements including one protection element 120 (step S105).

As shown in FIGS. 8 and 9 , the molded large-area PPTC substrate 110a may be cut along a lengthwise transmission line (a) and a widthwise cutting line (b) corresponding to the size of a unit device.

Through this, the open mode protection device 100, which is a unit device as shown in FIG. 10, can be completed.

Meanwhile, the method 10 of manufacturing an open mode protection device according to an embodiment of the present invention may further include plating electrode pads ( S104 ).

That is, after the molding step (S103), the lower surface electrode 114 of the large-area PPTC substrate 110a may be plated (step S104). At this time, the bottom electrode 114 of the large-area PPTC substrate 110a may be plated with any one of Ag, Pt, Sn, Cr, Al, Zn, and Au.

Through this, the solderability and electrical conductivity of the bottom electrode 114 used as the electrode pad of the unit element can be improved, and the electrode 114 can be protected if it is not easily worn or corroded.

As described above, the open mode protection device 100 manufactured by the open mode protection device manufacturing method 10 of the present invention may include the PPTC substrate 110 , the protection device 120 and the molding part 130 .

The open mode protection device 100 is used in an electronic device having an LED as a load, for example, a backlight (BLU) of a display device such as a TV, various lamps in a car, and smart lighting using dimming to protect a circuit. will be.

At this time, the open mode protection device 100 may be connected in parallel to each of the constant current source and the LED load. Here, the constant current source may supply a constant amount of current to the LED load. The constant current source may be any one of a constant current type power supply and a constant current driver.

In addition, the LED load may be composed of a plurality of LEDs. For example, the LED load is a plurality of LEDs connected in series, a plurality of LEDs connected in series, a plurality of LEDs connected in series connected in parallel, a plurality of LEDs connected in parallel, or a plurality of LEDs connected in parallel. They may be connected in series.

As an example, one side of the open mode protection device 100 may be connected to one side of the constant current source and the LED load, and the other side may be connected to the other side of the constant current source and the LED load. Here, one side of the open mode protection device 100 may be connected to the ground terminal. That is, this ground terminal may be connected to the negative side of the constant current source and the load, and may be connected to a common ground formed on the circuit board of the electronic device.

The PPTC substrates 110 may be formed as a pair and spaced apart from each other at regular intervals. Here, the upper electrode 112 of the PPTC substrate 110 is an internal electrode to be connected to the electrodes 122 and 124 at both ends of the protection element 120, and the lower electrode 114 is connected to the constant current source and load of the electronic device. It is an external electrode for

The PPTC substrate 110 is electrically connected in series to both ends around the protection device 120 and senses the temperature or current of the protection device 120 . At this time, when the load is opened due to damage to any one of the plurality of LEDs to be protected, all the current provided from the constant current source flows to the protection device 120 and the temperature or current of the protection device 120 increases as the PPTC The substrate 110 reduces the current of the protection element 120 .

The protection element 120 bypasses overvoltage or overcurrent by connecting both ends of the electrodes 122 and 124 to the internal electrodes 112 formed on the upper surfaces of each of the pair of PPTC substrates 110 . That is, the protection device 120 may pass overvoltage or overcurrent due to ESD, EOS, or surge flowing through one external electrode 114 to another external electrode 114 connected to the ground.

As a result, the open mode protection device 100 can protect the LED load by bypassing ESD, EOS or surge introduced from the outside to the ground. That is, since the resistance of the PPTC substrate 110 is very small, the open mode protection device 100 substantially functions as a protection device against ESD, EOS, or surge such as a varistor by means of the protection device 120 .

The protection device 120 bypasses a constant current of the constant current source to the ground through the external electrode 114 during the open mode operation of the load made of LEDs.

The molding part 130 may be formed to cover the upper side of the pair of PPTC substrates 110a and the protection element 120 . The molding unit 130 protects the pair of PPTC substrates 110a and the protection device 120 and packages them as a single device.

The molding portion 130 may fill the space portion 102 between the pair of PPTC substrates 110 . That is, the space portion 102 between the pair of PPTC substrates 110 formed as the pair of PPTC substrates 110 are spaced apart may be filled with a molding member.

As shown in FIG. 11, such an open mode protection device 100 may be represented as an equivalent circuit in which a protection device B such as a varistor and a PPTC device P are connected in series. At this time, the PPTC element (P) may be divided and disposed at both ends of the protection element (B).

That is, in the open mode protection device 100, one end of a pair of PPTC elements (P) is connected to a pair of external terminals, and both ends of the protection element (B) are connected to the other end of the pair of PPTC elements (P). By being connected, a pair of PPTC elements (P) and one protection element (P) can be connected in series with respect to the external terminal.

The open mode protection device 100 according to the embodiment of the present invention configured as described above has a low resistance value at a constant temperature of 80° C. to 120° C. That is, the open mode protection device 100 functions as a protection device such as a varistor to bypass static electricity or ESD, EOS, or surge flowing into a load to the ground to protect a circuit.

On the other hand, if the protection element 120 does not have a sufficient protective function against ESD, EOS or surge introduced from the outside, some of the LED loads are damaged by ESD, EOS or surge and the LED load is often in an open state. Occurs.

As such, when a load made of LEDs is opened by ESD, EOS, or surge from the outside, the current and voltage flowing through the open-mode protection device 100 continuously increase, causing the protection device 120 to overheat. That is, since the power source of the load is a constant current source, when the load is open, all of the constant current supplied from the constant current source flows into the open mode protection device 100 . At this time, the actual load of the constant current source is the open mode protection device 100, and in this case, since a constant current source continuously flows into the open mode protection device 100, the voltage rises infinitely.

For example, when a constant current source supplies a current of 400 mA and an LED load consists of 10 LEDs, a voltage of approximately 25 to 30 V is output across both ends of the load, but when the load is in an open state, the actual load is an open mode. As the voltage across both ends of the protection device 100 rises to the supply power level (200 to 300V), the open mode protection device 100, particularly the protection device 120, overheats.

At this time, when the open mode protection device 100 is overheated at a temperature of 150° C. to 200° C., the resistance of the PPTC substrate 110 rapidly increases and the amount of current flowing in the open mode protection device 100 is reduced. By reducing, since the temperature can be reduced by reducing the voltage across both ends of the protection element 120, heat generation can be suppressed. Accordingly, self-damage due to overheating of the protection element 120 can be prevented.

In addition, by suppressing abnormal overheating of the open mode protection device 100, damage to circuit components adjacent to the open mode protection device 100 is prevented, and when adjacent components are made of inflammable materials, for example, from LEDs. When a white sheet is disposed in front of the LED to improve the efficiency of the emitted light, it is possible to prevent a fire caused by ignition of a protection device.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments presented herein, and those skilled in the art who understand the spirit of the present invention may add elements within the scope of the same spirit. However, other embodiments can be easily proposed by means of changes, deletions, additions, etc., but these will also fall within the scope of the present invention.

100: open mode protection device 102: space unit
110a: large area PPTC substrate 110: PPTC substrate
112, 114: electrode 116: slit
120: protection element 122,124: electrode
130,130': molding part 130a: epoxy sheet

Claims (12)

A method of manufacturing an open mode protection device connected in parallel to a load composed of a constant current source and an LED,
forming slits at regular intervals on a large-area polymeric positive temperature coefficient (PPTC) substrate on which electrodes are formed on both sides;
mounting protective devices for bypassing overvoltage or overcurrent on the electrodes with the slit therebetween at regular intervals;
molding with a molding member to cover the upper side of the large-area PPTC substrate and the protection element; and
and cutting the molded large-area PPTC substrate into unit devices including one protection device. According to claim 1,
In the molding, the slit is filled with the molding member. According to claim 1,
The molding member is a method of manufacturing an open mode protection device made of epoxy. According to claim 3,
The molding step is a method of manufacturing an open mode protection device by pressing and heat-sealing an epoxy sheet on the upper side of the large-area PPTC substrate. According to claim 1,
After the molding step, the manufacturing method of the open mode protection device further comprising the step of plating the lower surface electrode of the large-area PPTC substrate. According to claim 5,
The plating step is a method of manufacturing an open mode protection device in which the lower electrode of the large area PPTC substrate is plated with any one of Ag, Pt, Sn, Cr, Al, Zn and Au. According to claim 1,
The method of manufacturing an open mode protection device in which the double-sided electrodes of the large-area PPTC substrate are formed by Ni or Cu plating. According to claim 1,
The forming of the slit determines the size of the predetermined interval according to the cutting precision of the cutting step. According to claim 1,
The method of manufacturing an open mode protection device in which the protection device is any one of a varistor, a suppressor, a gas discharge tube (GDT), and a diode. According to claim 1,
The mounting step is a method of manufacturing an open mode protection device for mounting the protection device on the large area PPTC board through an SMT soldering process. According to claim 1,
The large-area PPTC substrate is a method of manufacturing an open mode protection device made of a polymer layer in which a conductive filler is dispersed. According to claim 11,
The method of manufacturing an open mode protection device in which the conductive filler is made of carbon black material.

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