KR102305912B1 - Flexible printed circuit board manufacturing method - Google Patents

Abstract

The present invention discloses= a flexible printed circuit board manufacturing method for attaching a magnetic field shielding sheet to a flexible printed circuit board formed as a result of the sequential execution of copper foil laminate preparation, through hole forming, copper plating, circuit pattern forming, coverlay film temporary bonding, surface treatment, and post-processing steps. The method includes: (a) a step of preparing a magnetic field shielding sheet; (b) a step of performing non-destructive testing on the magnetic field shielding sheet to determine whether or not a magnetic field in a set reference range is shielded; and (c) a step of integrally attaching a magnetic field shielding sheet determined as normal in the (b) step to one surface of the flexible printed circuit board. According to the present invention, a component-tested magnetic field shielding sheet is attached to a manufactured flexible printed circuit board, non-destructive total inspection (inductance measurement) is performed on the magnetic field shielding sheet before the magnetic field shielding sheet attachment, and thus abnormal product attachment can be excluded, a stable quality can be ensured, and manufacturing costs can be reduced.

Description

Flexible printed circuit board manufacturing method

The present invention relates to a method for manufacturing a flexible printed circuit board in which the product is completed through a process of attaching a magnetic shielding sheet to the manufactured flexible printed circuit board after the primary manufacturing is completed, and a flexible printed circuit manufactured by the method It's about the board.

Electronic components developed as electronic products become smaller and lighter in weight, have excellent workability, strong heat and chemical resistance, heat resistance, and high durability against repeated bending, high-density wiring, no wiring errors, and easy assembly. The reality is that good and reliable flexible printed circuit boards (FPCBs) are widely applied. Specifically, these FPCBs are core parts of all electronic products, including cameras, computers and peripherals, HAND PHONE, VIDEO & AUDIO devices, and CAMCORDER. It is widely used in PRINTER, DVD, TFT LCD, satellite equipment, military equipment, and medical equipment.

On the other hand, electromagnetic waves refer to electric/magnetic wavelengths including electric fields, magnetic fields, and water pulse waves generated by electric or electronic products used in various places around us. In particular, electromagnetic waves generated from high-frequency electronic devices may cause malfunctions due to electromagnetic interference with nearby electronic devices.

Accordingly, as a film for shielding electromagnetic waves emitted from various electronic devices, an electromagnetic wave shielding film is essentially used in various fields. In particular, due to electromagnetic wave emission between components in various electronic products, wavelength interference may occur, which may cause malfunction or failure of electronic products.

As an example of various fields in which the electromagnetic wave shielding film is used, there is a smart device such as a tablet PC in which a user can freely take notes on a display screen using a smart pen.

The tablet PC includes a flexible printed circuit board and an electromagnetic wave shielding film attached to the back thereof. Conventionally, a combination of such a flexible printed circuit board and an electromagnetic wave shielding film was manufactured through the following process.

Specifically, in the prior art: 1. Preparation of copper clad laminate -> 2. Formation of through-holes -> 3. Conducting copper plating -> 4. Formation of circuit pattern through exposure/development/etching -> 5. Outer surface of copper clad laminate on which circuit pattern is formed Temporary bonding of electromagnetic wave shielding film and coverlay film to -> 6. Fully attach using hot press -> 7. Surface treatment such as washing and gold plating -> 8. Circuit inspection and outer processing A combination of a flexible printed circuit board and an electromagnetic wave shielding film was manufactured through the post-process sequentially.

That is, in the prior art, in order to attach the electromagnetic shielding film, the attachment of the electromagnetic shielding film and the coverlay film was glued to the outer surface of the copper clad laminate and completely attached by providing high temperature/high pressure through a hot press. There is a problem.

As such, when the electromagnetic shielding film attachment process is located in the middle of the entire manufacturing process of the flexible printed circuit board, there is a risk that the electromagnetic shielding film must be operated in the B-stage state in step 5. If a process defect occurs in the processes 6 to 8. above, there is a problem in that the cost burden for the loss of the electromagnetic wave shielding film is large.

In addition, since the electromagnetic wave shielding film in the semi-cured state, B-stage state, is in an unoriented state as shown in FIG. 1, it must go through a hot press process to realize the final performance. There is a disadvantage that orientation must proceed.

In addition, the proportion of the electromagnetic shielding film in the manufacturing cost of the flexible printed circuit board to which the electromagnetic shielding film is attached is about 30 to 40% or more. As a result, the cost burden is unavoidable.

In addition, since the orientation performance of the electromagnetic wave shielding film in the B-stage state is not implemented, it is not possible to conduct component inspection in a non-destructive manner for the performance test (permeability measurement) of the electromagnetic wave shielding film, and among many electromagnetic wave shielding films, We had no choice but to select samples and proceed in a destructive method, and as described above, even if defects do not occur in the 6. ~ 8. process, in the end, regarding the occurrence of performance deviation of the electromagnetic shielding film, the flexible printed circuit board and the attachment of the electromagnetic shielding film There is an economic loss problem that all sieves must be treated as defective.

Republic of Korea Patent Publication No. 10-2015-0083018 (published on July 16, 2015)

The present invention has been devised to solve the above-mentioned problems of the prior art. After the first production of the flexible printed circuit board is completed, the magnetic field shielding sheet is attached to the manufactured flexible printed circuit board, but the non-destructive magnetic field shielding sheet is attached. An object of the present invention is to provide a method for manufacturing a flexible printed circuit board that can secure stable quality and reduce manufacturing cost by attaching a normal product by performing a complete performance test, and a flexible printed circuit board manufactured by the method.

According to an aspect of the present invention, (a) a copper clad laminate preparation step, a through-hole forming step, a copper plating step, a circuit pattern forming step, a coverlay film temporary welding step, a surface treatment step, and a post-process step are sequentially performed to perform a flexible printed circuit forming a substrate; and (b) performing a performance test of the magnetic field shielding sheet and integrally attaching the magnetic field shielding sheet determined to be normal to one surface of the flexible printed circuit board.

The step (b) comprises the steps of: (b1) preparing a magnetic field shielding sheet; and (b2) determining whether to shield the magnetic field of the set reference range by non-destructive testing of the magnetic field shielding sheet.

The flexible printed circuit board may be a substrate for a digitizer.

In step (b), a pressure sensitive adhesive layer is provided on a magnetic field shielding sheet in a C-stage state with a binder attached to one surface, and the flexible printed circuit board and the flexible printed circuit board can be attached to each other through quick press or laminating. have.

The pressure-sensitive adhesive layer may be a thermosetting acrylic pressure-sensitive adhesive layer.

In step (b2), the magnetic field shielding sheet may be in a C-stage state in which a binder is attached to one surface, or in a state in which the binder is not attached.

In the step (b2), the inductance of the magnetic field shielding sheet is measured to determine whether there is a defect, and a non-destructive total inspection can be performed.

In the step (b2), the inductance of the magnetic shielding sheet is measured and defective through the magnetic shielding sheet non-destructive tester, and the magnetic shielding sheet non-destructive tester includes a tester body having a shielding sheet seating part on which the magnetic shielding sheet is seated; a shielding sheet fixing cover provided to cover the magnetic field shielding sheet seated on the shielding sheet seating part; and an inductance measurement and detection unit provided on the shielding sheet fixing cover to measure the inductance of the shielding sheet.

The shielding sheet fixing cover is provided rotatably with respect to the tester body, and the magnetic field shielding sheet non-destructive tester is provided on the tester body so as to be in contact with the shielding sheet fixing cover to detect the rotational state of the shielding sheet fixing cover rotation detection unit; and a control unit that transmits a driving signal to the inductance measurement and detection unit when a touch signal through the rotation sensing unit is sensed.

A communication hole may be provided in the shielding sheet fixing cover to communicate with the inductance measurement and detection unit.

The shielding sheet seating part may be made of a material capable of blocking electromagnetic noise from being transmitted from a lower side of the shielding sheet seating part to a magnetic field shielding sheet seated on an upper surface of the shielding sheet seating part.

The shielding sheet seating part may be made of an aluminum material.

The magnetic shielding sheet non-destructive tester, the shielding sheet fixing cover is rotatably coupled to reciprocate the shielding sheet fixing cover along the width or longitudinal direction of the magnetic shielding sheet seated in the shielding sheet seating portion reciprocating moving part ; a rotation detecting unit provided on the tester body to be in contact with the magnetic field shielding sheet to detect a rotational state of the shielding sheet fixing cover; and a control unit that transmits a driving signal to the inductance measurement and detection unit when a contact signal is detected through the rotation detection unit, wherein the control unit is configured to: A driving signal may be transmitted to the reciprocating unit.

According to the method for manufacturing the flexible printed circuit board of the present invention described above and the flexible printed circuit board manufactured by the method, the magnetic field shielding sheet that has been inspected for parts is attached to the manufactured flexible printed circuit board before the attachment process with the magnetic field shielding sheet. Since only normal products can be attached to the shielding sheet through non-destructive inspection (inductance measurement), it is possible to secure stable quality and reduce manufacturing costs.

In addition, when attaching a magnetic field shielding sheet after manufacturing a flexible printed circuit board, by attaching a fully cured C-stage magnetic field shielding sheet, there is no need to perform a hot press process for mutual attachment and quick press or Since it can be directly attached through laminating, the process time can be significantly shortened and the loss of the magnetic field shielding sheet due to process defects can be reduced.

In addition, the magnetic shielding sheet in the C-stage state can perform a non-destructive total performance test by itself. By selecting defective products through inductance measurement before attaching the magnetic shielding sheet, the occurrence of defects in flexible printed circuit boards due to defective parts is significantly reduced. can be reduced

1 is a view showing an electromagnetic wave shielding film in a B-stage (B stage) state;
2 is a flowchart sequentially illustrating a method for manufacturing a flexible printed circuit board according to an embodiment of the present invention;
3 is a view showing a magnetic field shielding sheet in a C-stage (C stage) state;
4 to 6 are perspective views showing a magnetic shielding sheet non-destructive tester for non-destructive performance test of a magnetic shielding sheet in a method for manufacturing a flexible printed circuit board according to an embodiment of the present invention;
7 is a cross-sectional view showing a state in which a performance test of a magnetic field shielding sheet is performed through a magnetic field shielding sheet non-aggression tester in a method for manufacturing a flexible printed circuit board according to an embodiment of the present invention;
8 and 9 are diagrams showing another example of a magnetic shielding sheet non-destructive tester for non-destructive performance test of a magnetic shielding sheet in a method for manufacturing a flexible printed circuit board according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and the scope of the invention to those of ordinary skill in the art will be completely It is provided to inform you. In the drawings, like reference numerals refer to like elements.

The method for manufacturing a flexible printed circuit board according to a preferred embodiment of the present invention is a method of attaching a magnetic field shielding sheet to a flexible printed circuit board formed through a plurality of steps sequentially. After attaching the magnetic shielding sheet, it is possible to secure stable quality and reduce manufacturing costs because only normal products can be attached to the magnetic shielding sheet through non-destructive total inspection before the attachment process between the flexible printed circuit board and the magnetic shielding sheet.

Hereinafter, the present invention will be described in detail with reference to Examples.

As shown in FIG. 2 , the method for manufacturing a flexible printed circuit board according to an embodiment of the present invention includes a copper clad laminate preparation step (S101), a through-hole forming step (S102), a copper plating step (S103), and a circuit pattern forming step (S104). ), the coverlay film temporary bonding step (S105), the surface treatment step (S106), and the post-processing step (S107) are sequentially performed to attach the magnetic field shielding sheet to the formed flexible printed circuit board.

The above-described steps for manufacturing the flexible printed circuit board will be briefly described as follows.

A copper clad laminate in which a copper clad layer is formed on a polyimide resin is prepared (S101), and the copper clad laminate is cut to fit a desired size. Thereafter, a through hole is formed in the cut copper clad laminate through CNC machining or laser machining (S102). Thereafter, copper plating is performed so that one surface of the copper clad laminate is electrically conductive (S103). Next, a photosensitive dry film is laminated and laminated on one surface of the copper clad laminate, and then sequentially exposed, developed, and etched to form a circuit pattern (S104).

Next, after laser processing to remove unnecessary parts, a coverlay film for circuit protection is temporarily bonded to the outer surface of the copper clad laminate on which the circuit pattern is formed (S105), and then these are laminated using the heat and pressure of a hot press. . Thereafter, after surface treatment such as washing and gold plating (S106), the flexible printed circuit board is completed through post-processes such as circuit inspection and outer processing (S107) (S100).

The present invention attaches a magnetic field shielding sheet (Magnetic Metal Powder (MMP)) to one side (opposite side of the side on which the circuit pattern is formed) of the completed flexible printed circuit board.

In an embodiment of the present invention, the flexible printed circuit board to which the magnetic field shielding sheet is attached is applied as a substrate for a digitizer.

Digitizer means an input device used to input design drawings or figures in digital format to a computer or mobile smart device by reading coordinates, which are analog data of the input source, and the user uses an input tool (pen, etc.) for coordinate recognition. to input the X and Y positions. That is, in the embodiment of the present invention, the flexible printed circuit board may input/transmit the position of X, Y two-dimensional coordinates.

The magnetic shielding sheet can induce more accurate recognition of X, Y coordinates through electromagnetic induction between the input tool and the flexible printed circuit board by applying an electromagnetic interference (EMI) absorber to absorb external noise.

Hereinafter, a process of attaching the magnetic shielding sheet will be described in detail with reference to FIG. 2 .

First, a magnetic field shielding sheet is prepared (S200). Here, the magnetic shielding sheet is prepared through a separate cutting so as to have a size corresponding to the outer size of the flexible printed circuit board completed through the various processes described above.

Next, it is determined whether the magnetic field shielding sheet is non-destructive to shield the magnetic field of the set reference range (S300).

Specifically, in step S300, the inductance (Ls) of the magnetic shielding sheet is measured to determine whether there is a defect, and a non-destructive method is performed to determine the defect.

In order to check whether the magnetic field shielding sheet is normally shielded, it is possible to check the magnetic permeability as an MMP performance factor. It determines whether it is normal or defective in a non-destructive way by measuring the inductance of

Ls: inductance, n: number of turns, φ: magnetic flux, I: current, B: magnetic flux density, S: area,

μ ₀ : vacuum permeability, H: magnetic field strength

In other words, in step S300, when the inductance value is within the set range, it is determined as a normal product, and when it is out of the set range, it is determined as defective, and the set range can be variably changed by the user.

As described above, in the present invention, only normal products are attached through non-destructive total inspection of the magnetic field shielding sheet before the actual attachment process between the flexible printed circuit board and the magnetic field shielding sheet, and products with reduced performance coefficient (permeability) can be filtered, so the digitizer flexibility It is possible to secure stable quality of printed circuit boards and reduce manufacturing costs.

On the other hand, in step S300, the inductance of the magnetic shielding sheet is measured and defective through the magnetic shielding sheet non-destructive tester 100 to be described later, and in this case, the magnetic shielding sheet is a C-stage with a binder attached to one side. state or may be applied in a state in which the binder is not attached.

If the magnetic field shielding sheet in step S300 does not include a binder, the binder attachment process may be additionally performed before step S400 to be described below is performed.

The magnetic field shielding sheet in the C-stage state means that the binder is fully oriented and fully cured as shown in FIG. 3, and due to such complete orientation/curing, non-destructive total inspection through inductance measurement is possible. . In addition, since the magnetic field shielding sheet of this C-stage is in a state in which the metal powder is completely oriented, there is an advantage that it does not need to go through a separate orientation process as well as a separate curing process (eg, a hot press process). .

Next, the magnetic field shielding sheet determined as normal in step S300 is integrally attached to one surface of the flexible printed circuit board to complete the digitizer flexible printed circuit board (S400).

In step S400, a pressure sensitive adhesive layer is prepared on a magnetic field shielding sheet in a C-stage state with a binder attached to one side, and the flexible printed circuit board and the flexible printed circuit board are attached to each other through quick press or laminating.

The pressure-sensitive adhesive layer is composed of only a pressure-sensitive adhesive without an intermediate base layer, and in an embodiment of the present invention, the pressure-sensitive adhesive layer is of a thermosetting type, and thus has an advantage in that it is significantly superior in heat resistance than the room temperature pressure-sensitive adhesive.

In an embodiment of the present invention, the pressure-sensitive adhesive layer is applied as a thermosetting acrylic pressure-sensitive adhesive layer. Thermosetting acrylic pressure-sensitive adhesives have superior properties in terms of adhesion to MMP and operating temperature compared to general thermosetting adhesives. On the other hand, thermosetting acrylic pressure-sensitive adhesives have MMP adhesion of 1,800 to 2,000 gf/inch and operating temperature of room temperature to 180 degrees, so they can exhibit excellent advantages when applied to the MMP attachment process.

In an embodiment of the present invention, the pressure-sensitive adhesive layer, specifically the thermosetting acrylic pressure-sensitive adhesive layer, is of a type applicable to the quick press process, and the quick press converts the thermosetting acrylic pressure-sensitive adhesive layer to a gel state by applying a high temperature, and in this state By applying high pressure, the magnetic field shielding sheet and the flexible printed circuit board can be attached in close contact with each other. In other words, in the case of hot press, the molding process takes about 90 to 120 minutes, but in the case of quick press, it takes about 120 to 280 seconds. have.

According to the embodiment of the present invention described above, after manufacturing the flexible printed circuit board is first completed, the magnetic field shielding sheet that has been inspected for parts is attached. Since only normal products can be attached through inspection, it is possible to secure stable quality and reduce manufacturing costs.

In addition, when attaching a magnetic field shielding sheet after manufacturing a flexible printed circuit board, by attaching a fully cured C-stage magnetic field shielding sheet, there is no need to perform a hot press process for mutual attachment and quick press or Since it can be directly attached through laminating, the process time can be significantly shortened and the loss of the magnetic field shielding sheet due to process defects can be reduced.

In addition, the magnetic shielding sheet in the C-stage state can perform a non-destructive total performance test by itself. By selecting defective products through inductance measurement before attaching the magnetic shielding sheet, the occurrence of defects in flexible printed circuit boards due to defective parts is significantly reduced. can be reduced

Hereinafter, the magnetic shielding sheet non-destructive tester for measuring the inductance of the magnetic shielding sheet in step S300 and determining the defect will be described in detail.

4 to 6, the magnetic field shielding sheet non-destructive tester 100 includes a tester body 110, a shielding sheet fixing cover 120, an inductance measurement detecting unit 130, a rotation detecting unit 140 and a control unit ( not shown).

First, the tester body 110 is provided with a shielding sheet seating portion 111 on its upper portion, and the magnetic shielding sheet 10 is seated on the upper portion of the shielding sheet seating portion 111, and a control unit (not shown) to be described later in its inner space. ), a variety of electronic components are arranged.

Here, the shielding sheet seating part 111 is made of a material capable of blocking electromagnetic noise from the outside, and specifically, a magnetic field shielding sheet seated on the upper surface of the shielding sheet seating part 111 from the lower side of the shielding sheet seating part 111 . (10) is made of a material capable of blocking the transmission of electromagnetic noise. As described above, various electrical components, such as PCBs, sensors, wires, etc. that generate electromagnetic noise to the outside, are disposed inside the tester body 110, that is, below the shielding sheet seating part 111. These noises prevent the magnetic field shielding sheet ( 10), a measurement error occurs through the inductance measurement and detection unit 130, which will be described later.

In the present invention, in order to reduce the occurrence of such an inductance measurement error, the shielding sheet seating part 111 is made of an electromagnetic wave blocking material, specifically, it may be made of an aluminum material.

In addition, as shown in FIG. 4 , a plurality of guides 112 for aligning and disposing the magnetic field shielding sheet 10 to a set position are coupled to the shielding sheet seating part 111 , and the coupling of the guides 112 . A plurality of guide coupling holes 113 are provided in the shielding sheet seating part 111 so that the position can be variably adjusted.

The magnetic field shielding sheet 10 may have various external sizes corresponding to the model of the smart device, and the user may align the magnetic field shielding sheet 10 by adjusting the coupling position of the guide 112 accordingly. .

Next, the shielding sheet fixing cover 120 is provided to partially or completely cover the magnetic field shielding sheet 10 seated on the shielding sheet seating part 111, and the magnetic field shielding sheet 10 seated on the shielding sheet seating part 111. is fixed by pressing toward the shielding sheet seating part 111, for example, in the related drawings, one end portion is rotatably provided through a hinge axis with respect to the inspector body 110, and the upper surface of the magnetic shielding sheet is partially covered. .

Next, the inductance measurement and detection unit 130 is a kind of LCR meter capable of measuring inductance (Inductance, L), capacitance (Capacitance, C) and resistance (Resistance, R), in the embodiment of the present invention, the shielding sheet fixing cover 120 The inductance of the magnetic shielding sheet 10 is measured so as to be rotatably provided at the same time as the fixing cover of the shielding sheet.

In the embodiment of the present invention, as shown in FIG. 6 to increase the inductance measurement accuracy of the magnetic field shielding sheet 10 , the shielding sheet fixing cover 120 has a communication hole 121 to communicate with the inductance measurement and detection unit 130 . ) is provided. In other words, it is possible to improve the accuracy of measurement by preventing a separate obstacle from being interposed between the portion of the inductance measurement and detection unit 130 that substantially performs inductance measurement and the magnetic field shielding sheet 10 .

Next, the rotation detecting unit 140 is provided on the tester body 110 to be in contact with the shielding sheet fixing cover 120 to detect the rotational state of the shielding sheet fixing cover 120 .

In order to measure the inductance of the magnetic shielding sheet 10, the magnetic shielding sheet 10 is seated on the shielding sheet seating part 111 after the shielding sheet fixing cover 120 is turned upward and then the magnetic shielding sheet 10 is seated, and then the shielding sheet The fixed cover 120 is rotated to the lower side to cover the magnetic field shielding sheet while pressing and fixing it over a certain period, and then measuring the inductance.

The rotation detecting unit 140 is a kind of limit switch, and comes in contact with the lower rotating shielding sheet fixing cover 120 to sense the rotational state. When a contact signal through the rotation detecting unit 140 is sensed, the control unit transmits a driving signal to the inductance measuring and detecting unit 130 so that actual inductance measurement is performed.

The control unit receives the measurement value of the inductance measurement and detection unit 130 and compares it with the reference setting range to determine whether the magnetic field shielding sheet 10 is normal or defective, and as shown in FIGS. 4 to 6 , the tester body 110 ) may be provided with a separate display 114 for displaying these measured values, and LEDs, buzzers, etc. may be provided to visually/auditively guide the result of failure.

On the other hand, through the above-described structure, since the inductance measurement and detection unit 130 is fixed to a specific area with respect to the entire area of the shielding sheet seating part 111, the size (horizontal, vertical) of the magnetic field shielding sheet 10 may increase. In this case, it may be difficult to measure the inductance of the central region of the magnetic shielding sheet and the separated peripheral region. The applicant of the present invention proposes an additional structure as follows in order to compensate for these shortcomings.

8 and 9, the magnetic field shielding sheet non-destructive tester 100 uses the shielding sheet fixing cover 120 in the width or length direction of the magnetic shielding sheet 10 seated on the shielding sheet seating part 111. It further includes a reciprocating unit 150 capable of reciprocating along.

Here, the reciprocating unit 150 includes a motor 151, a ball screw 152, and a moving block 153 capable of reciprocating along the ball screw by driving the motor, and the shielding sheet fixing cover 120 is a moving block. In addition to being coupled to the movable block to be movable at the same time as (153), the hinge is rotatably coupled to the movable block (153). On the other hand, although the reciprocating unit 150 has been described based on the ball screw type in the related drawings and the above description, it is not limited thereto, and various modules for linear reciprocation such as a gear-rack module and an LM guide module are applicable.

The control unit transmits a driving signal to the reciprocating unit 150, that is, the motor, when the measurement completion at the current measurement and detection position is confirmed through the inductance measurement and detection unit 130, and the shielding sheet fixing cover 120 and the inductance measurement and detection unit 130 ) may move laterally along the width or length direction of the magnetic field shielding sheet 10 so that the inductance measurement for another area is made again. In addition, the control unit may receive the set time information through the timer and transmit a periodic driving signal to the reciprocating unit 150 . Here, a plurality of rotation sensing units 140 are provided to correspond to the left and right reciprocation of the shielding sheet fixing cover 120 and the inductance measuring and detecting unit 130 in the main body of the tester to be spaced apart from each other.

In this way, by adopting a structure in which the inductance measurement and detection unit 130 can reciprocate at the same time by the left and right reciprocating movement of the shielding sheet fixing cover 120, even when the size of the magnetic shielding sheet 10 increases, multiple regions of the magnetic shielding sheet Since the inductance measurement can be performed automatically, it is possible to significantly improve the defect detection accuracy of the magnetic shielding sheet.

In the foregoing, the present invention has been shown and described in connection with preferred embodiments for illustrating the principles of the present invention, but the present invention is not limited to the construction and operation as shown and described as such. Rather, it will be apparent to those skilled in the art that many changes and modifications can be made to the present invention without departing from the spirit and scope of the appended claims.

10: magnetic shielding sheet 100: magnetic shielding sheet non-destructive tester
110: inspection machine body 111: shielding sheet seating part
112: guide 120: shielding sheet fixed cover
121: communication hole 130: inductance measurement detection unit
140: rotation detection unit 150: reciprocating unit

Claims (14)

(a) forming a flexible printed circuit board by sequentially performing the copper clad laminate preparation step, the through-hole forming step, the copper plating step, the circuit pattern forming step, the coverlay film temporary bonding step, the surface treatment step, and the post-processing step; and
(b) performing a performance test of the magnetic shielding sheet and integrally attaching the magnetic shielding sheet determined to be normal to one surface of the flexible printed circuit board,
Step (b) is,
(b1) preparing a magnetic field shielding sheet; and
(b2) non-destructive testing of the magnetic field shielding sheet to determine whether to shield the magnetic field of the set reference range;
In the step (b2), the inductance of the magnetic shielding sheet is measured and the defect is determined through the magnetic shielding sheet non-destructive tester,
The magnetic shielding sheet non-destructive tester,
a tester body having a shielding sheet seating portion on which the magnetic field shielding sheet is seated;
a shielding sheet fixing cover provided to cover the magnetic field shielding sheet seated on the shielding sheet seating part; and
and an inductance measuring and detecting unit provided on the shielding sheet fixing cover to measure the inductance of the shielding sheet. delete According to claim 1,
The flexible printed circuit board manufacturing method, characterized in that the substrate for a digitizer (digitizer). According to claim 1,
In step (b),
A flexible printed circuit board, characterized in that a pressure sensitive adhesive layer is provided on a magnetic field shielding sheet in a C-stage state having a binder attached to one surface, and the flexible printed circuit board is attached to each other through quick press or laminating. manufacturing method. 5. The method of claim 4,
The pressure-sensitive adhesive layer is a flexible printed circuit board manufacturing method, characterized in that the thermosetting acrylic pressure-sensitive adhesive layer. According to claim 1,
In the step (b2), the magnetic field shielding sheet is in a C-stage state with a binder attached to one surface or a state in which the binder is not attached. According to claim 1,
In the step (b2), the inductance of the magnetic field shielding sheet is measured to determine whether there is a defect, and a non-destructive total inspection is performed. delete According to claim 1,
The shielding sheet fixing cover is provided rotatably with respect to the tester body,
The magnetic shielding sheet non-destructive tester,
a rotation detecting unit provided on the inspection machine body so as to be in contact with the shielding sheet fixing cover to detect a rotational state of the shielding sheet fixing cover; and
The method of manufacturing a flexible printed circuit board according to claim 1, further comprising a control unit for transmitting a driving signal to the inductance measuring and detecting unit when a contact signal through the rotation sensing unit is sensed. According to claim 1,
The method for manufacturing a flexible printed circuit board, characterized in that the shielding sheet fixing cover is provided with a communication hole to communicate with the inductance measurement and detection unit. According to claim 1,
The shielding sheet seating part is made of a material capable of blocking electromagnetic noise from being transmitted from the lower side of the shielding sheet seating part to the magnetic shielding sheet seated on the upper surface of the shielding sheet seating part. 12. The method of claim 11,
The method for manufacturing a flexible printed circuit board, characterized in that the shielding sheet seating portion is made of an aluminum material. According to claim 1,
The magnetic shielding sheet non-destructive tester,
a reciprocating part to which the shielding sheet fixing cover is rotatably coupled so as to reciprocate the shielding sheet fixing cover along the width or length direction of the magnetic shielding sheet seated on the shielding sheet seating part;
a rotation detecting unit provided on the tester body to be in contact with the magnetic field shielding sheet to detect a rotational state of the shielding sheet fixing cover; and
Further comprising a control unit for transmitting a driving signal to the inductance measurement and detection unit when a touch signal is detected through the rotation sensing unit,
wherein the control unit transmits a driving signal to the reciprocating unit when the completion of measurement at the current measurement and detection position is confirmed through the inductance measurement and detection unit. delete

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