JP2015050455A - Printed circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed circuit board that allows preventing a component to be protected from static electricity by using potential difference formed between two spark gaps having different materials provided between a ground pattern and the component to be protected.SOLUTION: A printed circuit board according to the present invention includes a ground pattern, a component to be protected, and spark gaps interposed between the ground pattern and the component to be protected. The spark gaps are composed of a first metal pattern coupled to the ground pattern and a second metal pattern formed to spaced apart from the first metal pattern with a predetermined distance, so that static electricity due to potential difference can be induced to the ground, thereby protecting an electrostatic-sensitive component.

Description

  The present invention relates to a printed circuit board including a spark gap formed on a surface of a substrate for inducing static electricity to ground and grounding.

  As electronic devices become lighter, thinner and smaller, the density of small mobile devices and other electronic products is increasing. The spacing between components is narrow and the wiring density is high. Phenomena occur and can cause serious problems.

  In particular, microwave RF (radio frequency) devices have a very low tolerance for ESD impact. In fact, small ESD pulses can damage sensitive RF devices and other components.

  Since some RF devices require resistance to much larger ESD discharges, this is a drawback in circuit configuration and involves many limitations.

  Many RF devices are also very sensitive to parallel capacitance due to their operating frequency. Such sensitivity to parallel capacitance may further require the requirement that the ESD protection circuit must have very low capacitance.

  Therefore, the printed circuit board is provided with an electrostatic protection element that can block the static electricity in advance or discharge it to a specific position in order to protect a portion (component, pattern, via, etc.) that is vulnerable to static electricity. Electrostatic protection elements are typically used in telephone lines, power lines, and antenna feed lines to protect buildings and / or circuits connected thereto from lightning and other ESD incidents.

  However, in view of the trend of electronic devices to be lighter, thinner, and smaller, the mounting of electrostatic protection elements has the problem of causing spatial constraints in circuit pattern design and micro-element mounting, resulting in countering the trend of the times. It was.

Korean Published Patent No. 2006-0002238

  The present invention has been derived in order to solve the above-mentioned drawbacks and problems mentioned in the conventional printed circuit board, and includes two sparks of different materials provided between a ground pattern and an electrostatic protection body. It is an object of the present invention to provide a printed circuit board capable of protecting a protector from static electricity by utilizing a potential difference formed in a gap.

  The object of the present invention can be achieved by providing a printed circuit board including a ground pattern, a protector, and a spark gap interposed between the ground pattern and the protector.

  At this time, the spark gap may include a first metal pattern and a second metal pattern provided to face the first metal pattern.

  In addition, the first metal pattern and the second metal pattern may be spaced apart.

  In addition, protrusions may be formed on one side or both sides of the first metal pattern and the second metal pattern facing each other.

  In addition, the protrusions are gradually narrowed in a triangular shape, and the portions facing each other can have pointed tips.

  In addition, a protrusion may be formed on a side surface of the second metal pattern.

  The first metal pattern and the second metal pattern may be made of different metals.

  The first metal pattern may be provided in the ground pattern.

  The second metal pattern may be formed apart from the outer peripheral surface of the protector, and an insulating material may be formed between the second metal pattern and the outer peripheral surface of the protector.

  The first metal pattern may be made of copper (Cu), and the second metal pattern may be made of silver (Ag).

  The spark gap may include a first metal pattern provided in the ground pattern.

  The first metal pattern and the protector may be formed apart from each other, and an insulating material may be formed between the first metal pattern and the protector.

  In addition, the first metal pattern may have a protrusion toward the protector.

  As described above, the printed circuit board according to the present invention includes the first metal pattern connected to the ground pattern and the second metal pattern formed apart from the first metal pattern, and static electricity is grounded. It is possible to prevent the static electricity from being induced or induced by the protective body, and this has the advantage that the parts vulnerable to the static electricity can be protected.

  In addition, according to the present invention, a spark gap can be formed on the printed circuit board, which facilitates production and eliminates the need for attaching another antistatic element. There is an advantage that convenience is improved.

1 is a plan view of an embodiment of a printed circuit board according to the present invention. It is an enlarged view of the spark gap of FIG. It is a simulation figure which measures the instantaneous electric potential formed between conductors.

Specific contents for carrying out the invention

  Advantages and features of the present invention, and methods for accomplishing them, will become apparent with reference to the embodiments described in detail below in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and can be embodied in various different forms. The embodiments can be provided to complete the disclosure of the present invention and to fully convey the scope of the invention to those skilled in the art to which the present invention belongs.

  The terminology used herein is for describing the embodiments and is not intended to limit the present invention. In this specification, the singular forms include plural forms unless otherwise specified in the text. As used herein, “comprise” and / or “comprising” refers to a component, stage, operation and / or element referred to is one or more other components, stages, operations and Do not exclude the presence or addition of elements.

  FIG. 1 is a plan view of an embodiment of a printed circuit board according to the present invention, and FIG. 2 is an enlarged view of the spark gap of FIG.

  As shown in FIG. 1, the present invention may include a ground pattern 110, a spark gap 120, and a protector 130.

  The ground pattern 110 may be connected to the ground terminal of the power supply unit and serve as a reference potential for determining whether or not the printed circuit board 100 and elements mounted thereon operate, and is mounted on the printed circuit board 100. The component to be connected to the ground pattern 110 may be a reference current and / or a reference voltage for determining the level of the electrical signal.

  The spark gap 120 may be interposed between the ground pattern 110 and the protector 130 so that the first metal pattern 121 and the second metal pattern 122 face each other, and the first metal pattern 121 is grounded. The first metal pattern 121 may be equipotential with the ground pattern 110.

  Since the first metal pattern 121 is electrically connected to the ground pattern 110 and has the same reference potential as that of the ground pattern 110, the first metal pattern 121 is lower than static electricity formed in conductive patterns or vias that connect various elements and circuits to each other. A potential may be formed.

  The first metal pattern 121 and the second metal pattern 122 may be formed apart from each other by a predetermined distance. When the first metal pattern 121 and the second metal pattern 122 are connected and electrically short-circuited, the protector 130 cannot be protected from static electricity induced from the ground pattern 110, so that a configuration formed at predetermined intervals is appropriate. sell.

  In addition, the first metal pattern 121 and the second metal pattern 122 may be configured to face each other in parallel, and protrusions 123a and 123b may be formed on one or both sides facing each other.

  The protrusions 123a and 123b may gradually narrow in a triangular shape, and the portions facing each other may have sharp tips. That is, the protrusions 123a and 123b may have a sawtooth shape with a plurality of triangular shapes adjacent to each other, or may have a pattern in which the triangular shapes are separated.

  For example, the protrusion 123b is formed only on the surface of the second metal pattern 122 toward the first metal pattern 121, or the protrusion 123a is formed only on the surface of the first metal pattern 121 toward the second metal pattern 122. Alternatively, the protrusions 123a and 123b may be formed on both opposing surfaces of the first metal pattern and the second metal pattern 122. This utilizes the property that the charges formed on the metal surface easily gather at the point where the charges are sharp.

  The first metal pattern 121 is electrically connected to the ground pattern, and an insulating material is interposed between the first metal pattern 121 and the second metal pattern 122. It may be difficult for the static electricity applied instantaneously from 121 to transfer to the second metal pattern 122.

  In addition, static electricity induced toward the second metal pattern 122 can be spark discharged through the first metal pattern 121 connected to the ground pattern 110, and the static electricity is easily generated when moving to the ground pattern and grounding. Can be removed.

  The side surface of the second metal pattern 122 may further include a protrusion 123c. The side surface of the second metal pattern 122 may be spaced apart from the ground pattern 110 with an insulating material interposed therebetween, and has a triangular shape that narrows toward the ground pattern 110 and has a shape having a pointed tip. Static electricity formed on the pattern 122 can be easily induced to the ground pattern 110.

  Since the printed circuit board 100 tends to be light and thin, it may be advantageous to form the first metal pattern 121 and the second metal pattern 122 as close as possible. Since a short circuit may occur due to external environmental factors such as shrinkage and warping, the distance between the two locations is preferably designed to be 0.1 mm or more.

  Meanwhile, according to the present invention, static electricity is induced to the ground pattern 110 using the potential difference formed at both ends of the first metal pattern 121 and the second metal pattern 122, or the static electricity induced in the ground pattern 110 is instantaneously generated. In order not to transfer to the two metal patterns 122, the first metal pattern 121 and the second metal pattern 122 may be made of different metals.

FIG. 3 is a simulation diagram for measuring an instantaneous potential formed between conductors. Referring to this, when the first metal pattern 121 and the second metal pattern 122 are made of the same material (a combination of Cu—Cu, Au—Au, Ag—Ag), the potential difference formed at both ends is 3.054e ^−9. On the other hand, the potential difference formed at both ends in the case of different materials (combination of Cu-Au, Cu-Ag, Au-Ag) is 3.058e- ⁹ (V / m). It can be seen that the potential difference is higher when different materials are selected.

  When static electricity is induced at a high potential location, it can be induced to be released to a low location, and when induced at a low potential location, it can be prevented from moving to a high location.

  That is, even if static electricity is induced in the first metal pattern 121, the potential can not move to the second metal pattern 122, and when static electricity is induced in the second metal pattern 122, it is easier toward the first metal pattern 121. Can be moved to.

  The second metal pattern 122 may be formed apart from the outer peripheral surface of the protector 130. When the second metal pattern 122 is paired with the first metal pattern 121 connected to the ground pattern 110 to form the spark gap 120, a potential difference is formed between both ends. Since the protection body 130 is provided to protect against static electricity, the protection body 130 can be formed apart from the protection body 130 to prevent static electricity from moving.

  In addition, since an insulating material is formed between the second metal pattern 122 and the protector 130, static electricity formed on the second metal pattern 122 can be prevented from moving to the protector 130. The insulating material may be a general solder resist used for the substrate, or may be selected from known materials that exhibit a similar function.

  Meanwhile, the spark gap 120 may include only the first metal pattern 121 provided in the ground pattern 110. In addition, the first metal pattern 121 and the protector 130 may be formed apart from each other, and an insulating material for forming an electrical insulation state is provided between the first metal pattern 121 and the protector 130. Also good.

  Further, the first metal pattern 121 is formed with a protrusion 123a toward the protector 130, so that static electricity induced in the protector 130 can be removed by spark discharge toward the first metal pattern 121 or grounded. It is possible to prevent the static electricity input in the pattern from exceeding the critical value from being induced in the protector 130.

  The copper foil layer present on the printed circuit board 100 can be formed by plating, screen printing, or the like. The copper foil layer is alternately laminated with an insulating material and is composed of a plurality of layers so that photolithography can be performed from the surface coated with the insulating material. Only a specific part can be easily removed by an etching process or the like. Thereby, when the 1st metal pattern 121 or the 2nd metal pattern 122 consists of a copper foil layer, since it is not necessary to add a special process, there exists an advantage in a manufacturing process.

  In addition, when it is desired to form the spark gap 120 using a material other than the copper foil layer, the spark gap 120 can be easily applied by a screen printing method or the like. Not only can it be reduced, but the volume occupied in the substrate can be remarkably reduced, which is preferable in the trend of lighter, thinner and smaller devices.

  On the other hand, in the case where the spark gap 120 is formed of different materials, the potential difference applied to both ends of the first metal pattern 121 and the second metal pattern 122 may be an element to be considered with the highest priority. The rate may be a secondary factor to consider in selecting the material that forms the spark gap 120.

  When the spark gap 120 is formed of different materials, the potential difference does not deviate from the predetermined range regardless of the variety of materials of the first metal pattern 121 and the second metal pattern 122. Since the conductivity and resistivity are different for each metal, the potential difference can be an important indicator in the material selection of the spark gap 120.

  The electrical conductivity of the metal is a constant indicating the magnitude of the current flowing through the conductor, and is represented by the reciprocal of the resistivity (1 / Ω · m). The metal resistivity indicates an electrical resistance ratio of a conductor having a unit cross-sectional area and a unit length.

  Table 1 shows the degree to which the electricity of other metals flows when the conductivity of copper is 100%. The higher the conductivity and the lower the resistivity, the faster the static electricity moves. If such a material is selected as the material of the spark gap 120, the effect of removing static electricity is excellent.

  As can be seen from Table 1, silver not only has higher conductivity and lower resistivity than standard soft copper, but also has the property of not easily corroding. Moreover, since standard soft copper is cheap and there is not much difference between the conductivity of standard soft copper and the conductivity of silver, it is preferable to select standard soft copper as the material of the spark gap 120.

  Therefore, if one of the first metal pattern 121 and the second metal pattern 122 of the spark gap 120 is selected as silver, the other may be made of a copper foil layer.

  At this time, if the first metal pattern 121 is made of copper (Cu) and the second metal pattern 122 is made of silver (Ag), a high potential difference is formed in the second metal pattern 122 by the dissimilar material metal and the conductivity is high. Since the resistivity is low, the static electricity can easily move toward the ground pattern 110 and the static electricity can be prevented from moving toward the protector 130, which is most suitable for the object of the ESD protection of the protector. Become a combination.

  The copper foil layer can be designed by etching the solder resist of the substrate, and the spark gap 120 can be manufactured by selecting the first metal pattern 121 as a copper foil and screen printing the second metal pattern 122 with silver. May have advantages.

  The above detailed description illustrates the invention. Also, the foregoing is merely illustrative of a preferred embodiment of the present invention and the present invention can be used in various different combinations, modifications and environments. Changes or modifications may be made within the scope of the inventive concept disclosed herein, the scope equivalent to the disclosed disclosure, and / or the skill or knowledge of the art. The above-described embodiments are for explaining the best state in practicing the present invention, and are used in other states known in the art in using other inventions such as the present invention. Various modifications required for specific application fields and applications are possible. Accordingly, the above detailed description of the invention is not intended to limit the invention to the disclosed embodiments. Also, the appended claims should be construed to include other implementations.

DESCRIPTION OF SYMBOLS 100 Printed circuit board 110 Ground pattern 120 Spark gap 121 1st metal pattern 122 2nd metal pattern 123a, 123b, 123c Protrusion 130 Protector

Claims (13)

A grounding pattern;
A protector,
A printed circuit board comprising a spark gap interposed between the ground pattern and the protector.   The printed circuit board according to claim 1, wherein the spark gap includes a first metal pattern and a second metal pattern provided so as to face the first metal pattern.   The printed circuit board according to claim 2, wherein the first metal pattern and the second metal pattern are spaced apart from each other.   The printed circuit board according to claim 2, wherein a protrusion is formed on one side or both sides of the first metal pattern and the second metal pattern facing each other.   The printed circuit board according to claim 4, wherein the protrusions are gradually narrowed in a triangular shape, and portions facing each other have pointed tips.   The printed circuit board according to claim 2, wherein a protrusion is formed on a side surface of the second metal pattern.   3. The printed circuit board according to claim 2, wherein the first metal pattern and the second metal pattern are made of different metals.   The printed circuit board according to claim 2, wherein the first metal pattern is provided in the ground pattern.   The said 2nd metal pattern is spaced apart and formed in the outer peripheral surface of the said protector, and the insulating material is formed between the said 2nd metal pattern and the outer peripheral surface of the said protector. Printed circuit board.   The printed circuit board according to claim 2, wherein the first metal pattern is made of copper (Cu) and the second metal pattern is made of silver (Ag).   The printed circuit board according to claim 1, wherein the spark gap is formed of a first metal pattern provided in the ground pattern.   The printed circuit board according to claim 11, wherein the first metal pattern and the protector are formed apart from each other, and an insulating material is formed between the first metal pattern and the protector.   The printed circuit board according to claim 11, wherein a protrusion is formed on the first metal pattern toward the protector.

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