KR20190000507A - Method for manufacturing shielding sheet and shielding sheet manufactured by the method - Google Patents

Abstract

Presented are a method for manufacturing a shielding sheet to prevent deformation due to heat by directly forming a shielding layer of a mesh structure on a surface of a transparent base material through paste printing, and a shielding sheet manufactured thereby. The method forms a paste print layer on one surface of a base material with a transparent material through a paste printing process, sinters the paste print layer, and forms a shielding layer on one surface of the base material by etching the sintered paste print layer. The shielding layer is formed of a mesh pattern having a central portion formed with a plurality of holes, and an outer peripheral portion forms the shielding layer formed of a plate-shaped ground pattern.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for manufacturing a shielding sheet, and a shielding sheet produced by the method. BACKGROUND ART < RTI ID = 0.0 >

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shielding sheet disposed in a microwave oven door, and more particularly, to a shielding sheet manufacturing method for shielding electromagnetic waves generated during driving of a microwave oven from being emitted to the outside, and a shielding sheet manufactured thereby.

A microwave oven is a device that heats food using microwaves. That is, the microwave oven radiates a microwave to heat the food placed inside the cooking chamber.

Generally, a microwave oven is formed in a rectangular parallelepiped shape having an open side on one side, and includes a body formed in the cooking chamber and a door coupled to an open side of the body.

At this time, the door includes a door frame formed of a press-formed metal material and electrically connected to the main body so as to have high electrical conductivity, and a window for shielding electromagnetic waves while confirming the internal state of the cooking chamber.

At this time, the window is composed of a heat-resistant tempered glass and an electromagnetic wave shielding film.

The heat-resistant tempered glass is formed of a heat-resistant transparent material which can withstand the internal state of the cooking chamber and resist heat generated when the food is heated. For example, a Conv. Microwave oven including a heater may be made of a material having heat resistance of about 250 degrees or more.

The electromagnetic wave shielding film is a member for blocking the microwave from flowing out to the outside, and is formed of a thin metal plate. At this time, the electromagnetic wave shielding film is composed of a metal thin plate having a mesh structure in which a plurality of holes are formed because it is impossible to confirm the internal state of the cooking chamber when it is formed of a thin metal plate.

The electromagnetic wave shielding film is fixed through a door frame or a separate structure. That is, when the electromagnetic shielding film is attached to the heat resistant tempered glass through the adhesive, it is fixed through the door frame or the separate structure because it is detached from the heat resistant tempered glass by the heat generated in the cooking chamber when the food is heated.

However, since the conventional electromagnetic wave shielding film is not bonded to the heat resistant tempered glass, there is a problem that deformation such as lifting is caused by heat generated in the cooking chamber.

In addition, the conventional electromagnetic wave shielding film has a problem in that visibility is lowered because the excited portion is scratched or burnt by heat generated in the cooking chamber.

Korean Patent Publication No. 10-2013-0095363 (name: door for microwave oven)

Disclosure of Invention Technical Problem [8] The present invention has been proposed in order to solve the problems of the prior art described above, and it is an object of the present invention to provide a shielding sheet manufacturing method in which a shielding layer of a mesh structure is directly formed on a surface of a transparent substrate, It is an object of the present invention to provide a shielding sheet.

According to another aspect of the present invention, there is provided a method of manufacturing a shielding sheet, comprising: preparing a transparent base substrate; forming a paste printing layer on one side of the base substrate through a paste printing process; And forming a shielding layer on one surface of the base substrate by etching the paste printing layer. In the step of forming the shielding layer, the center portion is formed of a mesh pattern having a plurality of holes, Thereby forming a shielding layer formed of a ground pattern.

In preparing the base substrate, a transparent substrate selected from a PEN (polyethylene naphthalate) film, a PET (polyethylene terephthalate) film, a PI (polyimide) film, a PC (polycarbonate) film, a PSS Base substrate.

In the step of forming the paste printing layer, one paste selected from silver (Ag), ferrite, amorphous and permalloy may be printed to directly form the paste printing layer on one side of the base substrate.

In the sintering step, the paste printing layer can be sintered by applying heat of 520 DEG C or less.

A method of manufacturing a shielding sheet according to another embodiment of the present invention may further include laminating another base substrate on one side of the base substrate, and the shielding layer may be interposed between the base substrate and another base substrate.

According to another aspect of the present invention, there is provided a method of manufacturing a shielding sheet, comprising: preparing a transparent base substrate; forming a first paste printing layer on one side of the base substrate through a paste printing process; A step of sintering the first paste printing layer, a step of etching the first paste printing layer to form a mesh pattern at the center of one surface of the base substrate, a step of forming a second paste printing layer on one surface of the base substrate through a paste printing process And sintering the second paste printing layer to form a ground pattern on the outer periphery of the base substrate. At this time, the mesh pattern and the ground pattern may be formed to have different thicknesses.

A shielding sheet manufacturing method according to another embodiment of the present invention further includes laminating another base substrate on one side of the base substrate, wherein the shielding layer including the mesh pattern and the ground pattern is sandwiched between the base substrate and the other base substrate .

In order to achieve the above object, a shielding sheet according to an embodiment of the present invention includes a base material of a transparent material and a shielding layer formed directly on one surface of the base material, and the shielding layer includes a mesh pattern formed at the center of the base material, And a ground pattern formed on an outer peripheral portion of the printed circuit board.

At this time, the mesh pattern is formed with a transparency of 40% or more and an aperture ratio of 60% or more, and the mesh pattern and the ground pattern may be formed to have different thicknesses.

The base substrate may be a transparent substrate selected from the group consisting of PEN (Polyethylene Naphthalate) film, PET (Polyethylene Terephthalate) film, PI (Polyimide) film, PC (Polycarbonate) film, PSS (Poly styrene sulfonate) film and tempered glass.

A shielding sheet according to an embodiment of the present invention may further include another base substrate laminated on one surface of the base substrate, and a shielding layer may be interposed between the base substrate and another base substrate.

According to the present invention, a shielding sheet manufacturing method and a shielding sheet manufactured by this method can form a shielding layer integrally through a paste printing process on a base material of a transparent material, Can be prevented.

In addition, the shielding sheet manufacturing method and the shielding sheet manufactured by this method have the effect of preventing lifting of the shielding layer due to heat generated in the cooking chamber of the microwave oven by interposing the shielding layer between the base materials of transparent material .

In addition, the shielding sheet manufacturing method and the shielding sheet manufactured by the method can prevent the floating of the shielding layer, thereby solving the problem of the conventional electromagnetic shielding sheet in which the excited portion is scratched or burned and the visibility is lowered.

1 and 2 are views for explaining a method of manufacturing a shielding sheet according to a first embodiment of the present invention.
3 and 4 are views for explaining the step of forming the shielding layer of FIG. 1;
5 and 6 are views for explaining a method of manufacturing a shielding sheet according to a second embodiment of the present invention.
7 to 9 are views for explaining a method of manufacturing a shielding sheet according to a third embodiment of the present invention.
10 and 11 are views for explaining a method of manufacturing a shielding sheet according to a fourth embodiment of the present invention.
12 and 13 are views for explaining a shielding sheet according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to facilitate a person skilled in the art to easily carry out the technical idea of the present invention. . In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Referring to FIGS. 1 and 2, a method of manufacturing a shielding sheet according to a first embodiment of the present invention includes preparing a base substrate 100 (S110), forming a paste printing layer 200 (S130) And forming a shield layer 300 (S170).

In the step of preparing the base material 100 (S110), a base material 100 made of a transparent material is prepared for securing the visibility of the microwave oven. For example, in the step of preparing the base substrate 100 (S110), a selected one of PEN (Polyethylene Naphthalate) film, PET (Polyethylene Terephthalate) film, PI (Polyimide) film, PC (Polycarbonate) film and PSS Is prepared as the base substrate 100 as an example.

In the step of preparing the base material 100 (S110), the heat-resistant tempered glass of the microwave oven may be used. That is, in the step of preparing the base substrate 100 (S110), a heat-resistant tempered glass to be mounted on the door of the microwave oven may be prepared as the base substrate 100.

It should be noted that in the step of preparing the base substrate 100 (S110), any material capable of penetrating into the cooking cavity of the microwave oven other than the above-described materials can be modified.

In the step of forming the paste print layer 200 (S 130), paste is printed on one side of the base substrate 100 through the paste printing process to form the paste print layer 200. Here, in the step of forming the paste print layer 200 (S130), a silver paste is printed on one surface of the base substrate 100 to form a paste printed layer 200 having a thickness of about 5 m or more .

The paste printing layer 200 may be formed by printing a metal paste such as copper (Cu) on one surface of the base substrate 100 in the step of forming the paste printing layer 200 (S130).

In the sintering step S150, the paste base layer 100 is heated to a low temperature to sinter the paste printed layer 200. [ That is, in the sintering step (S150), when a PI film or a tempered glass having a high melting point is used as the base material 100, the paste printing layer 200 is sintered through a low-temperature sintering process. At this time, in the sintering step (S150), the paste printing layer 200 formed on the base substrate 100 is sintered by heating the base substrate 100 at a temperature of about 520 deg.

In the sintering step S150, the paste printed layer 200 may be sintered by irradiating the base substrate 100 with light. That is, when the selected one of the PEN film, the PET film, the PC film, and the PSS film having a low melting point is used as the base substrate 100 in the sintering step S150, the paste printing layer 200 is sintered through the light sintering process.

In the sintering step (S150), the paste printing layer (200) can be sintered through a heat sintering process or a light sintering process according to a binder, additives, and the like contained in the paste printing layer (200).

In the step of forming the shielding layer 300 (S170), the sintered paste printing layer 200 is etched to form a shielding layer 300 having a mesh structure in which a plurality of holes 320 are formed. For example, in the step of forming the shielding layer 300 (S170), a photoresist film is laminated on the sintered paste printing layer 200, and then a part of the paste printing layer 200 is etched to form a shielding layer 300 .

3 and 4, in the step of forming the shield layer 300 (S170), the center portion is formed of the mesh pattern 340 having the plurality of holes 320, and the ground pattern 360 having the outer peripheral portion having the predetermined line width. The shielding layer 300 is formed. Here, the central portion means an area not overlapping with the frame of the microwave oven door, and the outer circumferential portion means an area where at least a part overlaps with the frame of the microwave oven door. At this time, the mesh pattern 340 may be formed with a hole 320 having various cross-sectional shapes such as a hexagonal shape, a square shape, and a circular shape.

Since the line width of the mesh pattern 340 constituting the shielding layer 300 and the diameter and density of the holes 320 influence the electromagnetic wave shielding efficiency, the diameters of the holes 320 are minimized or the line width is minimized The mesh pattern 340 needs to be concentrated.

However, when the diameter of the hole 320 is minimized, transparency is lowered, which makes it difficult to use it as a shielding sheet for a microwave oven.

Therefore, it is preferable that the diameter of the hole 320 is minimized or the line width is minimized in a state where the transparency is about 40% or more and the aperture ratio is about 60% or more in the step of forming the shielding layer 300 (S170). At this time, the mesh pattern 340 has a line width of about 100 mu m and the hole 320 is formed to have a diameter of about 400 mu m as an example.

5 and 6, a method of manufacturing a shielding sheet according to a second embodiment of the present invention includes preparing a base substrate 100 (S210), forming a paste printing layer 200 (S230), sintering S250 Forming a shielding layer 300 (S270), and stacking (S290).

In the step of preparing the base material 100, a first base material 120 on which a shielding layer 300 is formed on one surface and a second base material 140 laminated on one surface of the first base material 120 are prepared do.

In the step of preparing the base material 100 (S210), a first base material 120 and a second base material 140 made of a transparent material are prepared for securing the visibility of the microwave oven. For example, in the step of preparing the base material 100 (S210), a selected one of PEN (Polyethylene Naphthalate) film, PET (Polyethylene Terephthalate) film, PI (Polyimide) film, PC (Polycarbonate) film and PSS Is prepared as the first base substrate 120 and the second base substrate 140 as an example. At this time, the first base material 120 and the second base material 140 of the same material are prepared in the step of preparing the base material 100 (S210), or the first base material 120 and the second base material The substrate 140 can be prepared.

In the step of preparing the base material 100 (S210), it may be a heat resistant tempered glass of a microwave oven. That is, in the step of preparing the base material 100 (S210), the tempered glass arranged in the direction of the cooking chamber of the microwave oven is prepared as the first base material 120, (140).

It is to be understood that the base material 100 may be modified into any material capable of penetrating the inside of the cooking chamber of the microwave oven in addition to the above-mentioned materials in the preparing step S210.

In step S230 of forming the paste print layer 200, paste is printed on one side of the first base substrate 120 through the paste printing process to form the paste print layer 200. [ Here, in the step S230 of forming the paste-printed layer 200, silver paste is printed on one surface of the first base substrate 120 to form the paste-printed layer 200 having a thickness of about 5 m or more .

In the step S230 of forming the paste print layer 200, a metal paste such as copper (Cu) may be printed on one side of the first base substrate 120 to form the paste print layer 200. [

In the sintering step (S250), the paste base layer (120) is heated to a low temperature to sinter the paste printed layer (200). That is, in the sintering step S250, when the PI base film 120 is used as a PI film or a tempered glass having a high melting point, the paste printing layer 200 is sintered through a low temperature sintering process. At this time, the paste printing layer 200 formed on the first base substrate 120 is sintered by heating the first base substrate 120 at a temperature of about 520 ° C in the sintering step (S250).

In the sintering step S250, the paste printing layer 200 may be sintered by irradiating the first base substrate 120 with light. That is, when the selected one of the PEN film, the PET film, the PC film, and the PSS film having a low melting point is used as the first base substrate 120 in the sintering step S250, the paste printing layer 200 is sintered do.

In the sintering step S250, the paste printing layer 200 can be sintered through a heat sintering process or a light sintering process according to a binder, an additive, and the like contained in the paste printing layer 200.

In the step S270 of forming the shielding layer 300, the sintered paste printing layer 200 is etched to form a shielding layer 300 having a mesh structure in which a plurality of holes 320 are formed. For example, in the step of forming the shielding layer 300 (S270), a photoresist film is laminated on the sintered paste printing layer 200, and a part of the paste printing layer 200 is etched to form a shielding layer 300 .

In the step of forming the shielding layer 300 (S270), the center portion is formed of the mesh pattern 340 having the plurality of holes 320, and the outer circumferential portion forms the shielding layer 300 formed of the ground pattern 360 having the predetermined line width As an example. Here, the central portion means an area not overlapping with the frame of the microwave oven door, and the outer circumferential portion means an area where at least a part overlaps with the frame of the microwave oven door.

Since the line width of the mesh pattern 340 constituting the shielding layer 300 and the diameter and density of the holes 320 influence the electromagnetic wave shielding efficiency, the diameters of the holes 320 are minimized or the line width is minimized The mesh pattern 340 needs to be concentrated.

However, when the diameter of the hole 320 is minimized, transparency is lowered, which makes it difficult to use it as a shielding sheet for a microwave oven.

Therefore, it is preferable that the diameter of the hole 320 is minimized or the line width is minimized in a state where the transparency is about 40% or more and the aperture ratio is about 60% or more in the step of forming the shielding layer 300 (S270). At this time, the mesh pattern 340 has a line width of about 100 mu m and the hole 320 is formed to have a diameter of about 400 mu m as an example. Here, the mesh pattern 340 may form holes 320 having various shapes such as a honeycomb shape, a square shape, a circular shape, and the like.

In the step of stacking (S290), the second base substrate 140 is laminated on the first base substrate 120. That is, in the step of stacking (S290), the second base substrate 140 is laminated on one surface of the first base substrate 120 on which the shielding layer 300 is formed.

Accordingly, the shielding sheet can prevent lifting of the shielding layer 300 due to heat generated in the cooking chamber of the microwave oven by interposing the shielding layer 300 between the two base substrates 100, The electromagnetic wave shielding sheet according to the present invention can solve the problem of the conventional electromagnetic wave shielding sheet which is deteriorated in visibility.

7 and 8, a method of manufacturing a shielding sheet according to a third embodiment of the present invention includes a transparent substrate preparation step S310, a first paste printing layer formation step S320, a first sintering step S330, forming a mesh pattern 340, forming a second paste print layer 240, and performing a second sintering process S360.

In the step of preparing the base material 100 (S310), a base material 100 made of a transparent material is prepared for securing the visibility of the microwave oven. For example, in the step of preparing the base material 100, a polyethylene naphthalate (PET) film, a polyethylene terephthalate (PET) film, a polyimide film, a polycarbonate film, a poly styrene sulfonate (PSS) And a selected one of the glasses is prepared as the base substrate 100. [ It should be understood that any modification capable of penetrating the inside of the cooking chamber of the microwave oven can be carried out.

In the first paste printing layer 220 forming step S320, the paste is printed on one side of the base substrate 100 through the paste printing process to form the first paste printing layer 220. [ In the first paste printing layer 220 forming step S320, silver paste is printed on one side of the base substrate 100 to form a first paste printing layer 220 having a thickness of about 5 m or more As an example.

In the first paste printing layer 220 forming step S320, a metal paste such as copper (Cu) may be printed on one side of the base substrate 100 to form the first paste printing layer 220.

Meanwhile, in the first paste print layer 220 forming step S320, the first paste print layer 220 may be formed only in a central portion of the one surface of the base substrate 100 that is not overlapped with the frame of the microwave oven door .

In the first sintering step (S330), the base substrate (100) is heated to a low temperature to sinter the first paste printing layer (220). That is, in the first sintering step (S330), when the PI film or the tempered glass having a high melting point is used as the base substrate 100, the first paste printing layer 220 is sintered through the low temperature sintering process. In this case, the first paste printing layer 220 formed on the base substrate 100 is sintered by heating the base substrate 100 at a temperature of about 520 ° C in the first sintering step (S330).

In the first sintering step S330, the first paste printing layer 220 may be sintered by irradiating light to the base substrate 100. [ That is, in the first sintering step (S330), if a selected one of the PEN film, the PET film, the PC film, and the PSS film having a low melting point is used as the base substrate 100, the first paste printing layer 220, Lt; / RTI >

In the first sintering step (S330), the first paste print layer 220 may be sintered through a thermal sintering process or a light sintering process according to a binder, an additive, and the like contained in the first paste print layer 220.

In the mesh pattern formation step S340, the sintered first paste layer 220 is etched to form a mesh pattern 340 having a plurality of holes 320 formed thereon. For example, in the step of forming the mesh pattern 340 (S340), a photoresist film is laminated on the sintered first paste printing layer 220, and a part of the first paste printing layer 220 is etched to form a mesh pattern 340 ).

At this time, since the line width of the mesh pattern 340, the diameter of the hole 320, the density, and the like affects the electromagnetic wave shielding efficiency, the diameter of the hole 320 is minimized or the line width is minimized, There is a need.

However, when the diameter of the hole 320 is minimized, transparency is lowered, which makes it difficult to use it as a shielding sheet for a microwave oven.

Therefore, it is preferable that the diameter of the hole 320 is minimized or the line width is minimized in a state where the transparency is about 40% or more and the aperture ratio is about 60% or more in the step of forming the mesh pattern 340 (S340). At this time, the mesh pattern 340 has a line width of about 100 mu m and the hole 320 is formed to have a diameter of about 400 mu m as an example. Here, the mesh pattern 340 may form holes 320 having various shapes such as a honeycomb shape, a square shape, a circular shape, and the like.

8, the mesh pattern 340 is formed only in the central portion of the base sheet through steps S320 through S340. However, the present invention is not limited thereto. For example, as shown in FIG. 9, (Not shown).

In the second paste print layer 240 forming step S350, the paste is printed on one side of the base substrate 100 through the paste printing process to form the second paste print layer 240. [ Here, in the second paste print layer 240 formation step (S350), a paste of the same material as the first paste print layer 220 can be printed. Here, the second paste print layer 240 is one selected from among metal pastes such as silver (Ag) paste and copper (Cu) paste.

Meanwhile, in the second paste print layer 240 forming step S350, a second paste print layer 240 is formed on an outer circumferential portion of the one surface of the base substrate 100 that is at least partially overlapped with the frame of the microwave oven door .

In the second sintering step (S360), the base substrate (100) is heated to a low temperature to sinter the second paste printed layer (240). That is, in the second sintering step (S360), when a PI film or a tempered glass having a high melting point is used as the base substrate 100, the second paste printed layer 240 is sintered through the low temperature sintering process. At this time, in the second sintering step (S360), the base substrate 100 is heated to a temperature of about 520 ° C to sinter the second paste printed layer 240 formed on the base substrate 100.

In the second sintering step S360, the second paste printing layer 240 may be sintered by irradiating the base substrate 100 with light. That is, in the second sintering step (S360), if a selected one of the PEN film, the PET film, the PC film, and the PSS film having a low melting point is used as the base substrate 100, the second paste printing layer 240, Lt; / RTI >

In the second sintering step (S360), the second paste printing layer 240 may be sintered through a thermal sintering process or a light sintering process according to a binder, additives, and the like contained in the second paste printing layer 240.

Here, the second paste printing layer 240 is sintered through a second sintering step (S360) to form a ground pattern 360. [

In the method of fabricating a shielding sheet according to the third embodiment of the present invention, the mesh pattern 340 is formed through steps S320 to S340, and the ground pattern 360 is formed through steps S350 and S360 to form the mesh pattern 340 And the ground pattern 360 can be formed with different thicknesses and materials (i.e., paste types).

That is, since the mesh pattern 340 can provide visibility of the microwave oven by providing a transparency and an aperture ratio equal to or more than a certain level, it is necessary to realize a fine line width (for example, about 100 μm) .

At this time, since the mesh pattern 340 must maintain a resistance higher than a certain level while realizing the fine line width, the mesh pattern 340 must be maintained at a certain thickness.

On the other hand, since the ground pattern 360 is formed in a plate shape, resistance higher than a certain level can be maintained and there is no restriction on the thickness unlike the mesh pattern 340.

Accordingly, even if the ground pattern 360 is formed to have a thickness smaller than that of the mesh pattern 340, the shielding performance is not greatly affected.

Therefore, the mesh pattern 340 and the ground pattern 360 may be formed of different materials and different thicknesses.

10 and 11, a method of manufacturing a shielding sheet according to a fourth embodiment of the present invention includes a transparent substrate preparation step S410, a first paste printing layer formation step S420, A second sintering step S460 and a laminating step S470 may be included in the formation of the mesh pattern 340, the formation of the mesh pattern 340, the formation of the mesh pattern 340,

In the step of preparing the base substrate 100, a first base substrate 120 on which a shielding layer 300 is formed on one surface and a second base substrate 140 laminated on one surface of the first base substrate 120 are prepared do.

In the step of preparing the base material 100 (S410), a first base material 120 and a second base material 140 made of a transparent material are prepared for securing the visibility of the microwave oven. For example, in the step of preparing the base substrate 100 (S410), a selected one of PEN (Polyethylene Naphthalate) film, PET (Polyethylene Terephthalate) film, PI (Polyimide) film, PC (Polycarbonate) film and PSS Is prepared as the first base substrate 120 and the second base substrate 140 as an example. At this time, the first base material 120 and the second base material 140 of the same material are prepared in the step of preparing the base material 100 (S410), or the first base material 120 and the second base material The substrate 140 can be prepared.

In the step of preparing the base substrate 100 (S410), it may be a heat resistant tempered glass of a microwave oven. That is, in the step of preparing the base material 100 (S410), tempered glass arranged in the direction of the cooking chamber of the microwave oven is prepared as the first base material 120, (140).

It is to be understood that the base material 100 may be modified into any material capable of penetrating the inside of the cooking chamber of the microwave oven in addition to the above-described material in the step of preparing the base material 100 (S410).

In the first paste print layer forming step S420, a paste is printed on one surface of the first base substrate 120 through a paste printing process to form a first paste print layer 220. [ In the first paste printing layer 220 forming step S420, silver paste is printed on one surface of the first base substrate 120 to form a first paste printing layer 220 having a thickness of about 5 m or more As an example.

The first paste print layer 220 may be formed by printing a metal paste such as copper (Cu) on one surface of the first base substrate 120 in the first paste print layer formation step S420.

On the other hand, in the first paste printing layer formation step S420, the first paste printing layer 220 is formed only on a central portion of the one surface of the first base substrate 120 that is not overlapped with the frame of the microwave oven door It is possible.

In the first sintering step (S430), the base substrate (100) is heated to a low temperature to sinter the first paste printing layer (220). That is, in the first sintering step (S430), when a PI film or a tempered glass having a high melting point is used as the base material 100, the first paste printing layer 220 is sintered through a low-temperature sintering process. At this time, in the first sintering step (S430), the base substrate 100 is heated to a temperature of about 520 ° C to sinter the first paste print layer 220 formed on the base substrate 100.

In the first sintering step (S430), the first paste printing layer 220 may be sintered by irradiating the base substrate 100 with light. That is, in the first sintering step (S430), when a selected one of the PEN film, the PET film, the PC film, and the PSS film having a low melting point is used as the base substrate 100, the first paste printing layer 220, Lt; / RTI >

In the first sintering step (S430), the first paste printing layer 220 may be sintered through a heat sintering process or a light sintering process according to a binder, an additive, and the like contained in the first paste printing layer 220.

In the mesh pattern formation step S440, the sintered first paste printing layer 220 is etched to form a mesh pattern 340 having a plurality of holes 320 formed therein. For example, in the step of forming the mesh pattern 340 (S440), a photoresist film is laminated on the sintered first paste print layer 220, and then a part of the first paste print layer 220 is etched to form a mesh pattern 340 ).

At this time, since the line width of the mesh pattern 340, the diameter of the hole 320, the density, and the like affects the electromagnetic wave shielding efficiency, the diameter of the hole 320 is minimized or the line width is minimized, There is a need.

However, when the diameter of the hole 320 is minimized, transparency is lowered, which makes it difficult to use it as a shielding sheet for a microwave oven.

Therefore, it is preferable that the diameter of the hole 320 is minimized or the line width is minimized in a state where the transparency is about 40% or more and the opening ratio is about 60% or more in the step of forming the mesh pattern 340 (S440). At this time, the mesh pattern 340 has a line width of about 100 mu m and the hole 320 is formed to have a diameter of about 400 mu m as an example. Here, the mesh pattern 340 may form holes 320 having various shapes such as a honeycomb shape, a square shape, a circular shape, and the like.

In the second paste print layer 240 forming step S450, the paste is printed on one side of the first base substrate 120 through the paste printing process to form the second paste print layer 240. [ Here, in the second paste print layer 240 formation step (S450), a paste of the same material as that of the first paste print layer 220 can be printed. Here, the second paste print layer 240 is one selected from among metal pastes such as silver (Ag) paste and copper (Cu) paste.

On the other hand, in the step of forming the second paste print layer 240 (S450), a second paste print layer 240 is formed on the outer circumferential portion, which is a region where at least a portion of the one surface of the first base substrate 120 overlaps with the frame of the microwave oven door .

In the second sintering step (S460), the base substrate (100) is heated to a low temperature to sinter the second paste printed layer (240). That is, in the second sintering step (S460), when the PI film or the tempered glass having a high melting point is used as the base substrate 100, the second paste printed layer 240 is sintered through the low temperature sintering process. At this time, in the second sintering step (S460), the base substrate 100 is heated to a temperature of about 520 ° C to sinter the second paste printing layer 240 formed on the base substrate 100.

In the second sintering step S460, the second paste printing layer 240 may be sintered by irradiating the base substrate 100 with light. That is, in the second sintering step (S460), if a selected one of the PEN film, the PET film, the PC film, and the PSS film having a low melting point is used as the base substrate 100, the second paste printing layer 240, Lt; / RTI >

In the second sintering step S460, the second paste printing layer 240 may be sintered through a thermal sintering process or a light sintering process according to a binder, additives, and the like contained in the second paste printing layer 240. [

Here, the second paste printing layer 240 is sintered through a second sintering step (S460) to form a ground pattern 360.

In the step of stacking (S470), the second base substrate 140 is laminated on the first base substrate 120. That is, in the stacking step S470, the second base material 140 is laminated on one surface of the first base material 120 on which the mesh pattern 340 and the ground pattern 360 are formed.

Accordingly, the shielding sheet can prevent lifting of the mesh pattern 340 due to heat generated in the cooking chamber of the microwave oven by interposing the mesh pattern 340 between the two base substrates 100, The electromagnetic wave shielding sheet according to the present invention can solve the problem of the conventional electromagnetic wave shielding sheet which is deteriorated in visibility.

Referring to FIG. 12, a shielding sheet according to an embodiment of the present invention includes a transparent base substrate 100.

The base substrate 100 is formed of a transparent material for ensuring the visibility of the microwave oven. Here, the base substrate 100 is one selected from a PEN (polyethylene naphthalate) film, a PET (polyethylene terephthalate) film, a PI (polyimide) film, a PC (polycarbonate) film and a PSS (poly styrene sulfonate) film.

A shielding layer 300 is formed on one side of the base substrate 100. The shielding layer 300 is directly formed on one surface of the base substrate 100 by paste printing and sintering. At this time, since the shielding layer 300 is directly formed on one surface of the base substrate 100 through the paste printing process, no separate adhesive layer is interposed between the base substrate 100 and the shielding layer 300.

The shielding layer 300 can be divided into a central portion which is an area not overlapping the frame of the microwave oven door and an outer peripheral portion which is a region overlapping the frame of the microwave oven door. At this time, the central portion of the shielding layer 300 is formed of a mesh pattern 340 having a plurality of holes 320, and the outer periphery thereof is formed of a plate-like ground pattern 360. The mesh pattern 340 and the ground pattern 360 may have different thicknesses and different thicknesses. The mesh pattern 340 may have a hole 320 having various cross-sectional shapes such as a hexagonal, Can be formed.

Since the line width of the mesh pattern 340 constituting the shielding layer 300 and the diameter and density of the holes 320 influence the electromagnetic wave shielding efficiency, the diameters of the holes 320 are minimized or the line width is minimized The mesh pattern 340 needs to be concentrated.

However, when the diameter of the hole 320 is minimized, transparency is lowered, which makes it difficult to use it as a shielding sheet for a microwave oven.

Accordingly, the center portion of the shielding layer 300 is formed of the mesh pattern 340 having a minimum transparency of about 40% or more and an aperture ratio of about 60% or more and minimizing the diameter of the hole 320 or minimizing the line width desirable. At this time, the mesh pattern 340 has a line width of about 100 mu m and the hole 320 is formed to have a diameter of about 400 mu m as an example.

Accordingly, the shielding sheet integrally forms the shielding layer 300 on the transparent base substrate 100 to prevent lifting of the shielding layer 300 due to heat generated in the cooking chamber of the microwave oven.

In addition, the shielding sheet and the manufacturing method thereof can solve the problem of the conventional electromagnetic shielding sheet in which the shielding layer 300 is prevented from lifting, thereby causing the excited portion to be grilled or burnt to reduce the visibility.

Referring to FIG. 13, the shielding sheet may be formed by stacking another base substrate 100 on one surface of the base substrate 100. That is, the shielding sheet may be formed by stacking two base substrates 100 and sandwiching the shielding layer 300 between the base substrates 100.

That is, the shielding sheet prevents lifting of the shielding layer 300 due to heat generated in the cooking chamber of the microwave oven through the shielding layer 300 between the transparent base base materials 100.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but many variations and modifications may be made without departing from the scope of the present invention. It will be understood that the invention may be practiced.

100: base substrate 120: first base substrate
140: second base substrate 200: paste printing layer
220: first paste printing layer 240: second paste printing layer
300: shielding layer 320: hole
340: Mesh pattern 360: Ground pattern

Claims (13)

Preparing a base material of a transparent material;
Forming a paste printing layer on one side of the base substrate through a paste printing process;
Sintering the paste printing layer; And
And etching the paste printing layer to form a shielding layer on one side of the base substrate,
Wherein the shielding layer is formed in a mesh pattern having a central portion formed with a plurality of holes, and the outer peripheral portion forms a shielding layer having a plate-shaped ground pattern. The method according to claim 1,
In the step of preparing the base substrate, one transparent substrate selected from PEN (polyethylene naphthalate) film, PET (polyethylene terephthalate) film, PI (polyimide) film, PC (polycarbonate) film, PSS Is prepared as a base substrate. The method according to claim 1,
Wherein the paste printing layer is formed by printing one selected from silver (Ag) and copper (Cu) to directly form a paste printing layer on one side of the base substrate. The method according to claim 1,
Wherein the paste printing layer is sintered by one selected from a heat sintering process and a light sintering process. The method according to claim 1,
Further comprising laminating a base substrate on one side of the base substrate,
Wherein the shielding layer is sandwiched between the base substrate and the other base substrate. Preparing a base material of a transparent material;
Forming a first paste printing layer on one side of the base substrate through a paste printing process;
Sintering the first paste printed layer;
Etching the first paste printing layer to form a mesh pattern at a central portion of one surface of the base substrate;
Forming a second paste printing layer on one side of the base substrate through a paste printing process; And
And sintering the second paste printing layer to form a ground pattern on an outer peripheral portion of the base substrate. The method according to claim 6,
Wherein the mesh pattern and the ground pattern have different thicknesses. The method according to claim 6,
Further comprising laminating a base substrate on one side of the base substrate,
Wherein the shielding layer including the mesh pattern and the ground pattern is sandwiched between the base substrate and the other base substrate. A transparent base substrate; And
And a shielding layer formed directly on one surface of the base substrate,
The shielding layer
A mesh pattern formed at a central portion of the base substrate; And
And a ground pattern formed on an outer peripheral portion of the base substrate. 10. The method of claim 9,
Wherein the mesh pattern has a transparency of 40% or more and an aperture ratio of 60% or more. 10. The method of claim 9,
Wherein the mesh pattern and the ground pattern have different thicknesses. 10. The method of claim 9,
Wherein the base substrate is a transparent substrate selected from the group consisting of PEN (Polyethylene Naphthalate) film, PET (Polyethylene Terephthalate) film, PI (Polyimide) film, PC (Polycarbonate) film, PSS (Poly styrene sulfonate) film and tempered glass. 10. The method of claim 9,
Further comprising another base substrate laminated on one surface of the base substrate,
Wherein the shielding layer is sandwiched between the base substrate and the other base substrate.

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