KR20210109342A - Mounting structure for surface mounted shield device - Google Patents

Abstract

Disclosed is a shield device having good mountability and excellent electromagnetic wave shielding effect. The shield device comprises: a box-shaped metal body integrally formed by a press with a closed upper portion and an open lower portion; a first thermoelectric element in a gel state that is self-adhesive to a lower surface of an upper wall of a body corresponding to a heating source and has spreadability by external force; and a second thermoelectric element that adheres to an upper surface of the upper wall of the body. The shield device is reel-taped so that a lower end of a sidewall of the main body is soldered to a circuit plate by a vacuum pickup and a corresponding place. Then, the first thermoelectric element by the place is in contact with the heating source by the spreadability and maintains contact with the heating source after soldering.

Description

Mounting structure for surface mounted shield device

The present invention relates to a mounting structure of a shielding device, and more particularly, to a technology capable of efficiently shielding electromagnetic waves generated from a heat source and rapidly transferring heat generated from the heat source for cooling.

As electronic devices and information communication devices are miniaturized and integrated, they are greatly affected by heat, static electricity, and electromagnetic waves. For example, as an electronic component mounted on a circuit board, a microprocessor has a faster processing speed, and a memory semiconductor has an increased density as its capacity increases, thereby generating a lot of heat and electromagnetic waves.

A metal shield can is used for electromagnetic wave shielding and heat transfer of electronic components or electronic component modules mounted on a printed circuit board.

According to the above patent, the shield frame and the shield cover must be separately supplied and combined, but the thermoelectric element applied to the shield cover may not contact the heat source due to assembly tolerances.

In addition, the mold cost and manufacturing cost of each of the shield frame and the shield cover are added, a separate assembly process is required, and a separate device for combining them with a uniform force is required, which may result in additional investment costs.

In addition, since the shield frame and the shield cover are mechanically coupled and made of a metal material, a mechanical gap is inevitably formed at the interface between them, resulting in easy inflow or outflow of electromagnetic waves. In frequency, this disadvantage can be greatly emphasized.

Accordingly, it is an object of the present invention to provide a mounting structure of a shield device capable of ensuring reliable contact between a thermoelectric element and a heat source.

Another object of the present invention is to provide a mounting structure of a shielding device that is suitable for mass production and easily provides reliable quality economically.

Another object of the present invention is to provide a mounting structure of a shielding device capable of rapidly transferring heat generated from a heat source while providing excellent shielding of electromagnetic waves generated from the heat source for cooling.

According to one aspect of the present invention, there is provided a mounting structure of a shield device for shielding electromagnetic waves by enclosing a heat source mounted on a circuit board and transferring heat generated from the heat source to a metal case, wherein the shield device is integrally formed to a box-shaped metal body with a closed upper portion and an open lower portion; a first thermoelectric element in a gel state that is self-adhesive to a lower surface of an upper wall of the body corresponding to the heat source; and a second thermoelectric element adhered to the upper surface of the upper wall of the main body, wherein the shield device is packaged in a carrier, and the shield device is vacuum picked up and placed on the solder cream formed on the conductive pattern of the circuit board, The first thermoelectric element comes into contact with the surface of the heat source and spreads by pressing force by the place, and after the place, when the shield device is reflow soldered, a soldering part including the lower end of the side wall of the main body is formed with the solder cream and ripple Mounting of a shield device, characterized in that the first thermoelectric element maintains a state in which the first thermoelectric element is in contact with the surface of the heat source and spreads by pulling the soldering part downward by a solidifying force while the solder cream is cooled and hardened. achieved by the structure.

Preferably, during the placement, all of the soldering parts positioned to correspond to the solder cream maintain contact with the solder cream, and all of the soldering parts positioned to correspond to the solder cream are soldered to the solder cream.

Preferably, the first thermoelectric element may be a cured thermally conductive silicone rubber.

The above object is a method of mounting a shield device that shields electromagnetic waves by enclosing a heat source mounted on a circuit board and transfers heat generated from the heat source to a metal case, wherein the shield device is integrally formed and has an upper portion a box-shaped metal body with an open bottom and closed; a first thermoelectric element in a gel state that is self-adhesive to a lower surface of an upper wall of the body corresponding to the heat source; and a second thermoelectric element adhered to the upper surface of the upper wall of the main body, wherein the mounting method includes: packaging and providing the shielding device in a carrier; vacuum-picking the shielding device from the externally exposed surface of the second thermoelectric element and placing it on the solder cream formed on the conductive pattern of the circuit board; and reflow soldering a soldering part including a lower end of a side wall of the body in contact with the solder cream with the solder cream, wherein when the placing, the first thermoelectric element is in contact with the surface of the heat source and the place spread with a pressing force by the 1 It is achieved by a method of mounting a shield device, characterized in that the thermoelectric element is in contact with the surface of the heat source and maintains a spread state

According to the present invention, since the shield device is integrally formed, it is easy to mount by surface mounting (SMT), and it is reliable in quality and economical, so it is suitable for mass production.

In addition, since the metal body is integrally configured so that the shielding device can shield electromagnetic waves and transfer heat well, it is possible to well shield the electromagnetic waves generated from the internal heat source and transfer heat generated from the heat source to the outside.

In addition, the first thermoelectric element in a gel state having spreadability by external force directly contacts the heating source and the metal body by placing, and then directly contacts the heating source and the metal body even after reflow soldering to release the heat generated from the heating source. It can be well transmitted to the outside through the first thermoelectric element and the metal body.

In addition, the first thermoelectric element provided before the place is a cured thermally conductive silicone rubber in a gel state, and it is easy to maintain the advantages initially provided as it is, and to provide various shapes including thickness.

1(a) and 1(b) are partially exploded perspective and cross-sectional views respectively showing a shielding device applied to the present invention.
2(a) and 2(b) show before and after mounting of the shield device of FIG. 1, respectively.
3(a) and 3(b) show different structures of the first thermoelectric element and the heating source, respectively.

It should be noted that the technical terms used in the present invention are only used to describe specific embodiments, and are not intended to limit the present invention. In addition, the technical terms used in the present invention should be interpreted as meanings generally understood by those of ordinary skill in the art to which the present invention belongs, unless otherwise defined in particular in the present invention, and excessively comprehensive It should not be construed in the meaning of a human being or in an excessively reduced meaning. In addition, when the technical term used in the present invention is an incorrect technical term that does not accurately express the spirit of the present invention, it should be understood by being replaced with a technical term that can be correctly understood by those skilled in the art. In addition, general terms used in the present invention should be interpreted as defined in advance or according to the context before and after, and should not be interpreted in an excessively reduced meaning.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1(a) and 1(b) are partially exploded perspective and cross-sectional views respectively showing the shielding device applied to the present invention, and FIGS. 2(a) and 2(b) are each before and after mounting the shielding device of FIG. indicates.

The shield device 100 is mounted on the circuit board 10 and covers the electronic components or modules 20 and 21 (hereinafter referred to as a heat source) that generate heat to emit heat generated from the heat source 20 and emit electromagnetic waves. used for shielding.

The heat source 20 may be at least one, and in the case of two or more, may have different heights or sizes, but is not limited thereto.

The shield device 100 is integrally formed and has a box-shaped metal body 110 with a closed upper part and an open lower part, self-adhesive to the lower surface of the upper wall 112 of the main body 110, and has spreadability by external force A first thermoelectric element 120 and a second thermoelectric element 120 adhered to the upper surface of the upper wall 112 of the body 110 are configured.

<Main body 110>

The body 110 may have a metal sheet formed by cutting and bending by a press, or may be integrally formed by deep drawing, and may be formed of a metal capable of reflow soldering or a metal capable of reflow soldering. It may consist of plated metal.

The main body 110 is formed in a box shape in which the upper part is blocked, the lower part is opened, and the upper wall 112 is closed, and the lower end of the side wall 111 is soldered to the circuit board 10 and fixed, so that an external electromagnetic wave is transmitted to the main body 110 . ) does not flow into the inside and the electromagnetic wave from the heat source 20 does not flow out.

The shape of the body 110 has various shapes such as a rectangle or a polygon, and the height of the body 110 of the present invention is preferably very low compared to the width and length, and may be about 2 mm to 10 mm, but is not limited thereto.

<First thermoelectric element 120>

The first thermoelectric element 120 is adhered to at least a portion of the lower surface of the upper wall 112 of the main body 110 by self-adhesive force, for example, a thermally conductive silicone rubber in a gel state is discharged by a dispensing dispensing device to be self-adhesive. can

The amount, shape, and application position of the first thermoelectric element 120 may be adjusted according to the size, shape, and position of the heat source 20 , the body 110 , and the like.

As an example, the first thermoelectric element 120 is preferably formed on at least 1/3 of the surface area of the lower surface of the upper wall 112 of the body 110 at a position corresponding to the heat source in consideration of spreading, and taking into account the spreading portion Therefore, it is not preferable to form the entire lower surface.

In this embodiment, the first thermoelectric element 120 is applied so that the vertical cross section of the central portion of the upper wall 112 of the main body 110 to have a half-moon shape.

The cross-sectional shape of the first thermoelectric element 120 is not particularly limited, but as shown in FIG. 1(b) , the first thermoelectric element 120 may be coated so that the vertical cross-section has a half-moon shape so that the thickness decreases from the center to the edge.

According to this structure, when the shield device 100 is vacuum picked up and placed on the solder cream of the circuit board 10, that is, when placed, as indicated by the arrow in FIG. 2(b), the first thermoelectric element ( 120) spreads or pushes from the center toward the edge so that it can be spread evenly without generating air bubbles.

The first thermoelectric element 120 is preferably a silicone rubber having self-adhesive force in which thermally conductive powder such as alumina or aluminum nitride or thermally conductive fiber is uniformly mixed, and has a thermal conductivity of 1 W/mK or more and may be electrically insulating.

The first thermoelectric element 120 is a cured thermally conductive silicone rubber that has spreadability due to external force, but is not only less deformed due to heat provided again or external shaking, etc., but also self-adhesive to the lower surface of the upper wall of the body 110 . It can maintain the viscosity and stickiness of the finished state even after soldering.

Here, the thermally conductive silicone rubber may satisfy the temperature condition of reflow soldering provided between 180°C and 260°C.

As described above, the first thermoelectric element 120 may be spread in several directions by an external force applied in the vertical direction due to the spreadability according to the viscosity. Here, one of the external forces is to vacuum the shielding device 100 . The pressing force at the time of placing by pickup may vary depending on the spring strength of the vacuum pickup nozzle or the height at the time of placing. In addition, the other may be a coagulation force provided when the molten solder cream is cooled and hardened during reflow soldering.

According to the present invention, the soldering unit including the lower end of the side wall 111 of the main body 110 and a part of the side wall 111 adjacent to the lower end by vacuum pickup and placing the shield device 100 packaged and supplied to the carrier generates heat. In the process of placing the source 20 on the circuit board 10 on which the source 20 is mounted on the solder cream, the vacuum pick-up nozzle presses the shield device 100 and the first thermoelectric element 120 by the corresponding pressing force causes the heat source 20 to It spreads in contact with the surface.

In addition, reflow soldering is performed after placing, and during reflow soldering, the soldering part is pulled downward by the solidification force when the molten solder cream solidifies while cooling, so that the first thermoelectric element 120 is placed on the surface of the heat source 20. spread and remain in contact.

As a result, the first thermoelectric element 120 of the shielding device 100 may maintain a spread state in contact with the surface of the heat source 20 .

<Second thermoelectric element 130>

In the shielding device 100 , the second thermoelectric element 130 is preferably adhered to the upper surface of the upper wall 112 of the main body 110 to a predetermined thickness.

The second thermoelectric element 130, for example, has elasticity and has no or very little self-adhesive force on the upper surface and can be vacuum picked up/placed, and has self-adhesive force only on the lower surface of the upper surface of the upper wall 112 of the body 110. It can be self-adhesive.

The second thermoelectric element 130 may cover all or more than 2/3 of the upper surface of the upper wall of the main body 110 based on the center.

The second thermoelectric element 130 is formed by, for example, printing and curing a liquid thermally conductive silicone rubber corresponding to a reflow soldering temperature on a metal sheet, or a cured cured product having elasticity on the upper surface of the upper wall 112 of the main body 110 . It can be formed by adhering a thermally conductive silicone rubber sheet by self-adhesive force.

In addition, the second thermoelectric element 130 may include a thermal diffusion sheet or a graphite sheet capable of withstanding the heat provided during reflow soldering in addition to the thermally conductive silicone rubber sheet.

The first thermoelectric element 120 and the second thermoelectric element 130 have a thermal conductivity of 1 W/mK or more and may be electrically insulating, and the first thermoelectric element 120 has a lower viscosity and spreadability than the second thermoelectric element 130 . can be good

Hereinafter, a process of mounting the shield device 100 will be described.

The shield device 100 is packaged in a carrier and vacuum picked up by a vacuum pick-up tool, and placed on the solder cream 14 on the solder land 12 of the circuit board 10 on which the heat source 20 is mounted.

Here, the carrier may be a reel carrier in a reel state or a tray in a bulk state.

At this time, by pressing the shielding device 100 so that the soldering part at the bottom of the sidewall of the main body 110 is buried in the solder cream 14, the influence of wind when the first thermoelectric element 120 is reflow soldered can be minimized. have.

In this process, the first thermoelectric element 120 indicated by a dotted line in FIG. 2( b ) is deformed while spreading while in contact with the surface of the heating source 20 by the pressing force by the pick-up tool.

After being placed, the first thermoelectric element 120 may contact and cover at least 1/2 of the entire or center of the upper surface of the heat source 20 .

Thereafter, when reflow soldering is performed, the soldering portion at the bottom of the sidewall 111 of the main body 110 is soldered by solder cream, and the molten solder cream is cooled and hardened, and the soldering portion is pulled downward by the coagulation force.

As a result, the first thermoelectric element 120 can spread over the surface of the heat source 20 and maintain a contact state, and all the soldering parts positioned corresponding to the solder cream 14 are soldered with the solder cream 14 to the main body. By preventing a gap from being formed between the 110 and the circuit board 10, electromagnetic wave shielding can be reliably performed.

According to the above embodiment, since the main body is composed of a single body and there is no assembly tolerance compared to the conventional shield device in which the shield frame and the shield cover must be separately supplied and combined, the first thermoelectric device is mounted in the process of mounting the shield device. The device can stably contact the heat source and reliably maintain contact even after mounting.

In addition, since the main body is composed of a single body, a separate assembly process is unnecessary, a separate device for assembling is not required, and there is no mechanical gap, so that electromagnetic waves are excellently shielded.

3(a) and 3(b) show different structures of the first thermoelectric element and the heating source, respectively.

In FIG. 3A , as a structure including two heat sources 20 and 21 and one first thermoelectric element 120 , the first thermoelectric element 120 spreads according to the amount applied to the heat source 23 . ) may spread only on the upper surface or flow down to the side to spread to a portion of the side surface of the heat source 23 .

In addition, in FIG. 3(b) , as a structure including two heat sources 20 and two first thermoelectric elements 120 and 121 corresponding thereto, the first thermoelectric elements 120 and 121 correspond to each other. Although formed smaller than the heating source 20 , it may be wider depending on the amount to be applied and may spread to a portion of the top and side surfaces of the heating source 20 .

In FIGS. 3A and 3B , the dotted line shows a shape in which the first thermoelectric elements 120 and 121 are initially applied to the lower surface of the upper wall 112 of the main body 110 .

Since the main body 110 is in contact with a metal case for cooling through the second thermoelectric element 130 , the heat generated from the heat generating source 20 is the first thermoelectric element 120 - main body 110 - The second thermoelectric element 130 - can be rapidly discharged through the metal case.

In particular, since the second thermoelectric element 130 preferably has elasticity, it is closely attached to the metal case to further improve heat transfer.

As described above, since the mounting structure of the shield device of the present invention does not use a separate medium for heat transfer or electromagnetic wave shielding, heat and electromagnetic waves generated from the heat source 20 of the circuit board can be efficiently and economically transmitted and shielded. There is an advantage that you can.

Those of ordinary skill in the art to which the present invention pertains may modify and modify the above-described contents without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: shield device
110: body
111: side wall
112: upper wall
120: first thermoelectric element
130: second thermoelectric element

Claims (4)

A mounting structure of a shielding device that surrounds a heat source mounted on a circuit board to shield electromagnetic waves, and transfers heat generated from the heat source to a metal case,
The shield device is
a box-shaped metal body formed integrally with the upper part blocked and the lower part open;
a first thermoelectric element in a gel state that is self-adhesive to a lower surface of an upper wall of the body corresponding to the heat source; and
Consists of a second thermoelectric element that is adhered to the upper surface of the upper wall of the main body,
When the shield device is packaged in a carrier and the shield device is vacuum picked up and placed on the solder cream formed on the conductive pattern of the circuit board, the first thermoelectric element comes into contact with the surface of the heat source and is formed by the place. spread under pressure,
After the placement, if the shield device is reflow soldered, the soldering part including the lower end of the side wall of the main body is reflow soldered with the solder cream, and the soldering cream is cooled and hardened while holding the soldering part downward by the coagulation force. The mounting structure of the shield device, characterized in that by pulling the first thermoelectric element in contact with the surface of the heat source and maintaining a spread state. In claim 1,
When placing, the soldering portion positioned to correspond to the solder cream maintains contact with the solder cream,
The mounting structure of the shield device, characterized in that all the soldering portions positioned corresponding to the solder cream are soldered to the solder cream. In claim 1,
The mounting structure of the shield device, characterized in that the first thermoelectric element is a cured thermally conductive silicone rubber. A method of mounting a shielding device for shielding electromagnetic waves by wrapping a heating source mounted on a circuit board and transferring heat generated from the heating source to a metal case, the method comprising:
The shield device is
a box-shaped metal body formed integrally with the upper part blocked and the lower part open;
a first thermoelectric element in a gel state that is self-adhesive to a lower surface of an upper wall of the body corresponding to the heat source; and
Consists of a second thermoelectric element that is adhered to the upper surface of the upper wall of the main body,
The mounting method is
packaging and providing the shielding device in a carrier;
vacuum-picking the shielding device from the externally exposed surface of the second thermoelectric element and placing it on the solder cream formed on the conductive pattern of the circuit board; and
Reflow soldering the soldering part including the lower end of the side wall of the main body in contact with the solder cream with the solder cream,
At the time of the place, the first thermoelectric element contacts the surface of the heat source and spreads by pressing force by the place,
During the soldering, the soldering part including the lower end of the side wall of the main body is reflow soldered with the solder cream, and as the solder cream is cooled and hardened, the soldering part is pulled downward by the coagulation force to cause the first thermoelectric element to generate the heat. A method of mounting a shield device, characterized in that it maintains a spread state in contact with the surface of the source.

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