KR20130018027A - Rigid fpcb and smt using the same - Google Patents

Abstract

PURPOSE: A rigid FPCB AND a SMT using the same are provided to stably perform the SMT process by using a dummy part for supporting the flexible region of a circuit board. CONSTITUTION: A base substrate is loaded. The base substrate includes a dummy part(125) for supporting an opening area. Parts are mounted on the base substrate. A cutting process is performed on an outer frame(220) and a connection part(a) of a substrate part. The substrate part has a rigid part(123) and a flexible part(127).

Description

Rigid circuit board and component mounting method using same {RIGID FPCB AND SMT USING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible circuit board, and in particular, a rigid printed circuit board (Rigid-) combining the advantages of a flexible printed circuit board (FPCB) and a rigid and reliable RIGID PCB. flexible printed circuit board) and a method for installing a component using the same.

In accordance with the thinner and higher integration of flat panel display devices such as liquid crystal display devices, the RIGID PCB and the flexible PCB on which the driving circuit of a conventional flat panel display device are mounted are wire bonded or TAB. The technology of electrically connecting through Tape Automated Bonding method has a limit in securing minimum margin between parts.

In order to overcome these limitations, a rigid-flexible printed circuit board having a structure in which rigid and flexible circuit boards are interconnected and interconnected to a flat panel display device is integrated. The application method is proposed. In particular, the above-mentioned flexible printed circuit board is advantageous for high integration of mounting elements and minimum margins due to high functionality of flat panel display devices such as liquid crystal display devices, which can eliminate unnecessary space by using connectors, thereby reducing thickness and size. It is suitable for the driving circuit of flat panel display device.

1 is a view schematically showing a structure of a conventional flexible circuit board.

As shown, the conventional flexible circuit board 20 is divided into a rigid portion 21 corresponding to the rigid substrate and a flexible portion 27 corresponding to the flexible substrate. A plurality of components 24 such as an IC are surface mounted on the 21, and the flexible portion 27 protruding from the rigid portion 21 is electrically connected to the wirings and terminals in the rigid portion 21. Thereafter, it is electrically connected to an external device such as an external substrate or a liquid crystal panel.

However, there is a problem in performing the SMT process using the flexible circuit board having the above-described structure.

First, the flexible part of the flexible circuit board has a flexible characteristic, and thus, parts that are distorted or uncontacted between terminals often occur due to shaking in the component mounting step.

In addition, when the substrate is exposed to high heat during the heat treatment process, the substrate is struck by the flexible loading, and thus, the substrate is distorted at the original mounting position during the TAB process.

In order to solve the above-described problem, as shown in FIG. 2 during the Surface Mount Technology (SMT) process, a separate carrier jig 70 for supporting the substrate 20 is provided, and the jig ( A method of loading the substrate 20 on the 70) and performing the SMT process has been proposed. However, there is a limit to the number of substrates 20 that can be mounted on one jig 70, and the steps of loading the substrate 20 onto the jig 70, transferring the substrate, and the substrate on the jig 70. The process of taking out (20) is added, and the number of people performing work is required for each process, which causes a decrease in productivity.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to solve a problem of deterioration in productivity during an SMT process according to the flexible characteristics of the flexible region of the flexible circuit board.

In order to achieve the above object, a component mounting method using a flexible circuit board according to a preferred embodiment of the present invention is divided into a buried region and an opening region, the base substrate on which a dummy portion for supporting the opening region is disposed Loading; Mounting at least one component on the base substrate; Cutting the connection part of the outer frame including the dummy part and the substrate part by machining or laser processing; And taking out the substrate part from the outer frame.

The mounting of at least one component on the base substrate may include applying a cream solder to one surface of the base substrate; Mounting at least one component in the area where the cream solder is applied; And electrically connecting the component and the flexible circuit board by pressing and heating.

The buried region is characterized in that at least one circuit pattern is formed.

The buried region is a rigid (RIGID) portion of the flexible circuit board.

The opening region may be a flexible portion of the flexible circuit board.

Prior to loading the base substrate, preparing the base substrate; Forming a first substrate layer on one surface of the base substrate; And forming a second substrate layer facing the first substrate layer on the other surface of the base substrate and having a dummy portion.

In order to achieve the above object, a flexible circuit board according to a preferred embodiment of the present invention, the substrate portion divided into a buried region and an opening region; An outer frame bordering the substrate; And a connection part connecting the substrate part and the outer frame, wherein at least one surface of the opening region has a dummy part directly connected to the outer frame.

The buried region is a rigid (RIGID) portion of the flexible circuit board.

The opening region may be a flexible portion of the flexible circuit board.

According to a preferred embodiment of the present invention, when manufacturing the flexible circuit board for component mounting, further comprising a dummy portion for supporting the flexible region of the circuit board, it is possible to proceed more stably SMT process without the addition of a support member and cost have. Therefore, it is possible to minimize defects of the flexible circuit board and increase productivity of the board.

1 is a view schematically showing a structure of a conventional flexible circuit board.
FIG. 2 is a diagram illustrating an example of a carrier jig used in an SMT process of a conventional flexible circuit board.
3 illustrates a flexible circuit board according to an embodiment of the present invention.
4 is a cross-sectional view taken along the line IV-IV 'of the flexible circuit board shown in FIG.
5 is a flowchart illustrating a method of mounting a component on a flexible circuit board according to an exemplary embodiment of the present invention.
FIG. 6 is a flowchart illustrating an SMT process of mounting a component using a substrate frame manufactured through the manufacturing process of FIG. 5.
7 is an exploded perspective view illustrating a structure of a liquid crystal display including a flexible circuit board according to an exemplary embodiment of the present invention.

Hereinafter, a flexible circuit board and a component mounting method using the same according to a preferred embodiment of the present invention with reference to the drawings. The drawings referred to in the following description are not intended to limit the shapes and positions of the components to the illustrated forms, and in particular, the drawings may be partially configured to assist in understanding the structure and shapes of the flexible circuit board which is a technical feature of the present invention. The scale of an element is exaggerated or reduced.

3 illustrates a flexible circuit board according to an embodiment of the present invention. As shown, the flexible circuit board 200 of the present invention consists of a substrate portion 120 that substantially constitutes the flexible circuit board, and an outer frame 220 that is removed after taking out the substrate portion 120.

The flexible circuit board 200 is configured to form a plurality of substrates 120 in one frame, and when the SMT process is completed, the substrate 120 that becomes a circuit board substantially performs a mechanical cutting process. Taken out through, the outer frame 220 is discarded. Therefore, the normal circuit pattern is not formed in the outer frame 220.

The above-described substrate part 120 is divided into a rigid part 123 and a flexible part 127. As the rigid part 123, a circuit pattern is patterned on a predetermined hard insulating layer. The interior of the rigid portion 123 overlaps with the flexible portion 127 to fill a portion thereof. The rigid part 123 may be formed in such a manner that a plurality of rigid insulating layers having different circuit patterns formed therebetween with an insulating layer interposed therebetween, and are electrically connected to each other through via holes or the like.

The above-described substrate unit 120 is locally connected to the outer frame 220 bordering it outward, and connecting portion connecting the substrate unit 120 and the outer frame 220 for easy extraction after the SMT process. (a) is formed narrow so that the width | variety may be easy to cut | disconnect.

In addition, the base substrate protrudes a predetermined length toward one side of the rigid portion 123. This protrusion is defined as an opening area as the flexible portion 127 of the flexible circuit board. The flexible part 127 has a circuit pattern patterned on a predetermined flexible insulating film, and forms a base substrate of a flexible circuit board so that the rigid part 123 is stacked on both sides.

Here, the rigid parts 123 stacked on both sides of the base substrate may extend from one surface and overlap the flexible part 127. That is, the rigid part 123 is electrically connected between the patterned circuit patterns formed on the front and rear surfaces in one region of the base substrate with respect to the base substrate, and a part of the rigid part 123 is up to the flexible part 127. It extends and forms the one surface of the flexible part 127.

The above-described extension area is a dummy part 125, which is generally formed at the same time as the rigid part 123 opposite to the surface on which the component is mounted, and the flexible part 127 is moved or flipped due to pressure during the SMT process. This prevents parts from being mounted more stably. The dummy part 125 remains in the outer frame 220 at the time of taking out the substrate part 120, so that the dummy part 125 no longer remains in the taken out flexible circuit board.

According to the above-described structure, the flexible circuit board of the present invention has a dummy part, which is an extension region of the rigid part, is further formed on the rear side of the flexible part of the flexible property, so that the flexible part is supported during the SMT process, so that a separate support such as a carrier jig is supported. The member can be omitted and the component can be mounted on the substrate stably. Hereinafter, the internal structure of the substrate will be described through the cross section of the flexible circuit board according to the embodiment of the present invention with reference to the drawings.

4 is a cross-sectional view taken along the line IV-IV 'of the flexible circuit board shown in FIG.

As illustrated, the substrate portion 120 of the flexible circuit board of the present invention may include a rigid portion 123 including a first substrate layer 122 and a second substrate layer 124 stacked on both sides of the base substrate. The base substrate may include a flexible portion 127 having an opening region in which a portion is embedded into the rigid portion 123 and a portion is exposed to the outside. Here, the rigid part 123 and the flexible part 127 have a form in which one or more insulating plates on which a circuit pattern is patterned are stacked in multiple layers.

Here, the flexible part 127 has a circuit pattern 121 formed on both sides of a film-type flexible circuit board and is formed of a multilayer, and a multilayered first substrate layer 122 having a circuit pattern is stacked on an upper surface thereof. In addition, a plurality of second substrate layers 124 having a circuit pattern on a lower surface of the flexible unit 127 are stacked to face the first substrate layer 122 described above. That is, the first and second substrate layers 122 and 124 are stacked except for the flexible portion 127 around the flexible portion 127 which is a base substrate, and the substrate layers alternate between the insulating layer and the circuit pattern layers. It may be in the form of being stacked.

At this time, a plurality of wirings or terminals 41 formed of copper foil layers are formed on one substrate layer, and a plating layer 42 is formed thereon. Here, the plating layer 42 may be omitted. Moreover, the insulating layer 45 is formed in the upper part, and the copper foil layer or the flexible copper foil laminated board 50 is laminated | stacked. According to the designer's intention, in the case of more laminated structures, the insulating layer may be stacked on top of the stacked structure.

In addition, a dummy part 125 is formed at the same time as the second substrate layer 124 on the lower surface of the flexible part 127. The dummy part 125 is formed at a position overlapping with the protruding flexible part 127 and serves to support the flexible part 127 on the lower surface.

Since the dummy part 125 is formed together with the second substrate layer 124 in the same process, the circuit pattern 121 may be omitted since the dummy part 125 has the same stacked structure but is not an area to which a signal is transmitted.

According to this structure, the flexible part 127 is fixed by the dummy part 125 to prevent the shaking due to vibration in the process progression, the flipping by heating and pressurization, etc., without the carrier jig in the SMT process, thereby making the SMT process more stable. Can be performed.

In addition, the dummy part 125 is left in the outer frame 220 of FIG. 3 when the substrate part 123 is taken out and discarded together. These are cut together at the time of cutting the connecting part (a of FIG. 3) and no separate cutting process is added. Hereinafter, a method of manufacturing a flexible circuit board according to a preferred embodiment of the present invention will be described with reference to the drawings.

5 is a flowchart illustrating a method of manufacturing a flexible circuit board according to an exemplary embodiment of the present invention.

As shown, the method of manufacturing a flexible circuit board according to the present invention includes preparing a base substrate (S300), forming a first substrate layer including a dummy part (S310) and opposing the first substrate layer. In operation S320, a second substrate layer is formed. Here, in steps S310 and S320 in which the first and second substrate layers are formed, the order of the first and second substrate layers may be changed.

In more detail, the preparing of the base substrate (S300) is a step of preparing a flexible film, in which one or more circuit patterns are formed to be a base substrate for lamination of the substrate layer. Here, polyimide (PI) and Teflon (PTEE) may be used as the flexible film.

Next, forming a first substrate layer including a dummy part (S310) is a step of forming a first substrate layer by stacking an insulating layer having at least one circuit pattern embedded under a base substrate having a circuit pattern. The upper part of the base substrate is a part in which components are mounted in the SMT process, and the lower part is a part loaded in the conveyor of the SMT process. Here, the first substrate layer is formed of a first pattern included in the rigid part, the circuit pattern is formed and electrically connected to the base film, and a dummy part extending from the rigid part to support the lower part of the flexible part.

Next, the step (S320) of forming the second substrate layer facing the first substrate layer may include the above-described first material on the first region of the first substrate layer formed in step S310, that is, the base substrate. It is a step of forming the 2nd board | substrate layer which consists of a 2nd area | region which opposes 1 area | region. Here, the first and second regions are portions corresponding to the rigid substrate in the flexible circuit board, and the opening region of the base substrate, that is, the portion where the first and second substrate layers are not formed, is the portion corresponding to the flexible substrate. . Thus, one flexible circuit board having a dummy part is completed. Hereinafter, an SMT process using a flexible circuit board according to a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 6 is a flowchart illustrating an SMT process of mounting a component using a flexible circuit board manufactured by the manufacturing method of FIG. 5.

As shown, the SMT process using the flexible circuit board of the present invention, the step of loading the flexible circuit board (S400), the step of applying a cream solder (cream solder) on the circuit board (S410), Mounting at least one component in the region where the cream solder is applied (S420), electrically connecting the component and the flexible circuit board through pressing and heating (S430), and the substrate portion from the outer frame. Taking out the step (S440).

The step of loading the flexible circuit board (S400) is a step of loading a base substrate divided into a buried region and a dummy part on a stage and then supplying it on a line for bonding. In this step, unlike a conventional SMT process, a separate carrier jig for supporting the base substrate is not used.

A step of applying a cream solder on the circuit board (S410) is a step of applying a cream solder on the mounting position of the component device on the base substrate, that is, the electrode.

Mounting at least one component in the area where the cream solder is applied (S420) is a step of placing the component element in a predetermined position using the SMT equipment. At this time, since the dummy part is formed on the rear surface of the opening area of the base substrate, the component can be mounted without any supporting means for the opening area, that is, the flexible area.

 In the step S430 of electrically connecting the component and the flexible circuit board through pressing and heating, a predetermined amount of heat is applied by using a reflow soldering apparatus to melt the cream solder applied onto the substrate. This is the step. At this time, heating temperature becomes about 220 degreeC.

Taking out the substrate part from the outer frame (S440) is a finishing step of the SMT process, and the base substrate completed up to the reflow soldering process supplied from the shearing equipment is taken out of the outer frame using the cutting equipment and the flexible circuit board Step to complete. In this case, as the cutting method used, a laser cutting method or a cutting method using a cutting machine may be applied, and not only an outer frame, but also a dummy part connected thereto is separated to separate only the part used as the actual rigid substrate. That is, the connection part a shown in FIG. 3 is cut out, and the board | substrate part is taken out.

According to the above-described steps, according to the component mounting method using the flexible substrate of the present invention, it can be seen that the substrate can be manufactured through the same process as in the prior art without a separate jig. Hereinafter, an example of a liquid crystal display device to which a flexible circuit board manufactured according to the technical spirit of the present invention is applied with reference to the drawings.

7 is an exploded perspective view illustrating a structure of a liquid crystal display including a flexible circuit board according to an exemplary embodiment of the present invention.

As shown, the liquid crystal display device including the flexible circuit board of the present invention includes a liquid crystal panel 100 for displaying an image and a backlight unit 150 for providing light thereto, and various mechanical structures 130, 140, 160 are mechanically coupled and modular.

First, the liquid crystal panel 100 is composed of a liquid crystal layer interposed between the first substrate 101 and the second substrate 102 at a predetermined distance and interposed therebetween. Typically, the first substrate 101 is formed to be larger than the second substrate 102, and the flexible circuit board 120 on which the driver IC 115 is mounted is electrically connected to the first substrate 101.

The liquid crystal panel 100 implements an image as various signals are applied from the driver IC 115. On the first substrate 101, a thin film transistor as a switching element, various wirings, and pixel electrodes are formed. The second substrate 102 is a color filter substrate for displaying RGB color, and a color filter, a black matrix BM, and a common electrode facing the pixel electrode are formed. The driver IC 115 may include a gate driver that provides a scan signal for turning on / off the above-described thin film transistor, and a data driver that provides a data signal to the pixel electrode. The liquid crystal panel 100 may be electrically connected to the liquid crystal panel 100 through the flexible region 127 of the flexible circuit board.

The liquid crystal panel 100 will be described in more detail. In the first substrate 101, a plurality of gate wirings and data wirings arranged in one direction to define a plurality of pixel regions are formed, and each pixel region is formed in the first substrate 101. A thin film transistor which is a switching element is formed. In addition, the thin film transistor includes a gate electrode connected to a gate wiring, a semiconductor layer formed by laminating amorphous silicon, etc. on the gate electrode, a source electrode and a drain electrode formed on the semiconductor layer and electrically connected to the data wiring and the pixel electrode. Is done.

The second substrate 102 is a color filter composed of a plurality of sub-color filters that implements red, green, and blue colors, and distinguishes each sub-color filter and transmits light passing through the liquid crystal layer. The blocking black matrix BM and a common electrode facing the pixel electrode of the first substrate 101 are formed. Here, the common electrode may be formed in parallel with the pixel electrode on the first substrate 101 instead of the second substrate 102 in the transverse electric field method according to the driving mode of the liquid crystal panel 100.

The first and second substrates 101 and 102 configured as described above are joined to face each other by a sealant formed on the outer side of the image display area to form the liquid crystal panel 100. A first polarizing plate and a second polarizing plate are attached to the second substrates 101 and 102, respectively, to polarize light incident and output to the liquid crystal panel 100 to implement an image.

The driver IC 115 is mounted in the rigid region 123 of the flexible circuit board in an SMT manner, and at least one end of the flexible region 127 protruding in one direction is the lower substrate 101 of the liquid crystal panel 100. Is electrically connected). The flexible region 127 of the flexible circuit board can be folded as a flexible material, and the rigid region 120 is folded and assembled in the rear direction of the liquid crystal panel 100 during modularization.

The backlight unit 150 is composed of the LED lamp 151 and the lamp substrate 152 to which the LED lamp 151 is bonded, which are disposed on one side of the lower side of the liquid crystal panel 100 and emit light. An LED array, a light guide plate 155 disposed under the liquid crystal panel 100 to guide light emitted from the LED lamp 151 to the liquid crystal panel 100, and a liquid crystal panel 100 and a light guide plate 155. The optical sheet 157 is formed of one or more diffusion sheets and prism sheets provided therebetween to diffuse and collect light guided by the light guide plate 155.

Although the drawing shows an example in which the LED lamp 151 is disposed on one side surface of the light guide plate 155 as the light metering backlight unit, the shape is disposed on both side surfaces of the light guide plate 155 or the light guide plate 115 is omitted. The direct type backlight unit in which the lamp 151 is disposed on the rear surface of the liquid crystal panel 100 may also be applied.

The liquid crystal panel 100 and the backlight unit 150 described above are seated on an upper portion of each corner portion of the guide panel 130, and the backlight unit 150 is formed on the rear surface of the liquid crystal panel 100 inside the guide panel 130. Is placed in the direction.

The guide panel 130 is a synthetic resin structure having a rectangular frame shape, in which the liquid crystal panel 100 is seated and borders the backlight unit 150.

The top case 140 has a structure covering the non-display area where an image is not implemented on the front surface of the liquid crystal panel 100 by bordering each corner at the upper portion of the liquid crystal panel 100, the guide panel 130, and a cover bottom to be described later. 160 is mechanically fastened.

The cover bottom 160 mounts the liquid crystal panel 100 and the backlight unit 150 therein and is coupled to the top case 140 from the front to modularize the liquid crystal display. Although not shown, the cover bottom 160 may be fastened using a separate coupling member such as a screw to maintain the coupling rigidity with the top case 140.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

120: substrate portion 123: rigid portion
125: dummy part 127: flexible part
200: flexible circuit board 220: outer frame

Claims (9)

Loading a base substrate partitioned into a buried region and an opening region, the base substrate having a dummy portion supporting the opening region on one surface;
Mounting at least one component on the base substrate;
Cutting the connection part of the outer frame including the dummy part and the substrate part by machining or laser processing; And
Taking out the substrate part from the outer frame
Component mounting method using a flexible circuit board comprising a. The method of claim 1,
Mounting at least one component on the base substrate,
Applying a cream solder to one surface of the base substrate;
Mounting at least one component in the area where the cream solder is applied; And
Electrically connecting the component and the flexible circuit board by pressing and heating
Component mounting method using a flexible circuit board, characterized in that consisting of. The method of claim 1,
The buried region is a component mounting method using a flexible circuit board, characterized in that at least one circuit pattern is formed. The method of claim 1,
The buried region is a rigid circuit board manufacturing method, characterized in that the rigid (RIGID) portion of the flexible circuit board. The method of claim 1,
And the opening region is a flexible portion of the flexible circuit board. The method of claim 1,
Before loading the base substrate,
Preparing the base substrate;
Forming a first substrate layer on one surface of the base substrate; And
Forming a second substrate layer on the other surface of the base substrate opposite the first substrate layer and having the dummy part;
Component mounting method using a flexible circuit board further comprising a. A substrate portion partitioned into a buried region and an opening region;
An outer frame bordering the substrate; And
It includes a connecting portion for connecting the substrate and the outer frame,
At least one surface of the opening region, the flexible circuit board, characterized in that the dummy portion is connected directly to the outer frame. The method of claim 7, wherein
And the buried region is a rigid (RIGID) portion of the flexible circuit board. The method of claim 7, wherein
And the opening region is a flexible portion of the flexible circuit board.

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