KR20110042994A - Flexible printed circuits board and display device using the same - Google Patents

Abstract

PURPOSE: A flexible printed circuit board and display device including the same are provided to prevent crack which generates around a bonding area by the generation of gap difference in case of attaching a flexible printed circuit board to a panel. CONSTITUTION: A flexible printed circuit board is mounted in a mounting area. A bonding area includes a plurality of substrate pads. A bonding area(BDA1, DBA2) includes a plurality of substrate pad groups and is located in the outside of the mounting area. A non-bonding area is located in both sides of the bonding area.

Description

Flexible Printed Circuits Board and Display Device using the same

The present invention relates to a flexible printed circuit board and a display device using the same.

With the development of information technology, the market for a display device, which is a connection medium between a user and information, is growing. Accordingly, the use of display devices such as organic light emitting display (OLED), liquid crystal display (LCD), plasma display panel (PDP), and the like is increasing.

Such a display device is used for various purposes in a computer field such as a notebook (note book) or an industrial field such as a mobile phone in a home appliance field such as a television (TV) or a video.

Some of the aforementioned display devices, for example, an organic light emitting display device or a liquid crystal display device, are driven by a driver that drives a plurality of subpixels arranged in a matrix form. The driver includes a timing driver, a scan driver, a data driver, and the like. The timing driver receives system signals such as the vertical sync signal Vsync, the horizontal sync signal Hsync, and the data signal DATA from the outside, generates various drive signals in response thereto, and supplies them to the scan driver and the data driver. . The timing driver, the scan driver, and the data driver are integrated on one chip or divided into one or more chips according to the size of the panel of the display device and formed on the panel or the flexible circuit board.

In the display device as described above, a flexible circuit board connected to an external circuit board is used to directly receive a system signal or various driving signals according to the size of the panel. The flexible circuit board is attached to the panel by an anisotropic conductive film (ACF). However, in the case of the conventional flexible circuit board, there is a crack problem such as cracking or cracking around the bonding area due to a step difference from the panel due to its structural characteristics, and thus improvement thereof is required.

The present invention for solving the above problems of the background art, a flexible circuit board and a display using the same that can prevent the crack (Crack) problem, such as cracks or cracks around the bonding area due to the step difference when attached to the panel To provide a device.

The present invention as a means for solving the above problems, the mounting area in which the element is mounted; At least two bonding areas disposed on an outer side of the mounting area, each bonding area including a plurality of substrate pad groups; And a non-bonding region disposed on both outer edges of at least one of the bonding regions and formed to be thicker than the thickness of the layers constituting the bonding region.

The layers included in the non-bonding region may further include at least one layer than the layers included in the bonding region.

The bonding region includes a base film layer, an adhesive layer located on one surface of the base film layer, and a metal layer located on one surface of the adhesive layer, and the non-bonding area includes a dummy metal layer and a dummy metal layer formed of the same material as the base film layer, the adhesive layer, and the metal layer. It may include a protective layer located on one surface.

The dummy metal layer may be connected to a wiring to which a low potential voltage is supplied.

Located in the non-bonding region may include an alignment mark formed on both ends of the substrate pad group.

In another aspect, the present invention, a display panel; A plurality of panel pad groups formed on the display panel; And a mounting area in which the device is mounted, a bonding area having at least two parts disposed on the outside of the mounting area, having a plurality of pad groups, and a thickness of the layers constituting the bonding area, located at both outer sides of at least one of the bonding areas. A display device including a flexible circuit board including a thicker non-bonding region is provided.

The layers included in the non-bonding region may further include at least one layer than the layers included in the bonding region.

The bonding region includes a base film layer, an adhesive layer located on one surface of the base film layer, and a metal layer located on one surface of the adhesive layer, and the non-bonding area includes a dummy metal layer and a dummy metal layer formed of the same material as the base film layer, the adhesive layer, and the metal layer. It may include a protective layer located on one surface.

The dummy metal layer may be connected to a wiring to which a low potential voltage is supplied.

Located in the non-bonding region may include an alignment mark formed on both ends of the substrate pad group.

The present invention provides a flexible circuit board that can prevent cracking problems such as cracking or cracking around the bonding area by removing the step between the bonding area and the non-bonding area around the bonding area to attach to the panel. It is effective to provide a display device. In addition, the present invention has the effect of providing a flexible circuit board and a display device using the same that can enhance the EMI shielding function.

Hereinafter, with reference to the accompanying drawings, the specific content for the practice of the present invention will be described.

1 is a plan view of a flexible circuit board according to an embodiment of the present invention, FIG. 2 is a partially enlarged view of the flexible circuit board shown in FIG. 1, and FIGS. 3 and 4 are cross-sectional views of the region shown in FIG. 1. .

As shown in FIGS. 1 to 4, the flexible circuit board according to the exemplary embodiment of the present invention includes mounting areas SMA, bonding areas BDA1 and DBA2, and non-bonding areas NBDA1 and NBDA2.

The mounting area SMA is an area in which the device U is mounted. In the drawings, the device U mounted in the mounting area SMA is only illustrated to facilitate understanding of the description, and the exemplary embodiment is not limited thereto. The mounting area SMA is formed thicker than the layers constituting the bonding areas BDA1 and BDA2. For example, adhesive layers, first metal layers, second metal layers, and protective layers may be disposed on upper and lower surfaces of the mounting area SMA based on the base film layer, but are not limited thereto.

The bonding areas BDA1 and BDA2 are areas attached to the panel and the external substrate. At least two bonding areas BDA1 and BDA2 are disposed on the outside of the mounting area SMA and include a plurality of substrate pad groups SPAD1 and SPAD2, respectively. The first substrate pad group SPAD1 included in the first bonding region BDA1 is attached to the panel, and the second substrate pad group SPAD2 included in the second bonding region BDA2 is attached to the external substrate. . The first substrate pad group SPAD1 included in the first bonding region BDA1 and the second substrate pad group SPAD2 included in the second bonding region BDA2 are each anisotropic conductive film (ACF) or the like. By the panel and the external substrate. At least one of the bonding areas BDA1 and BDA2, for example, the first bonding area BDA1 may include an adhesive layer 182 and an adhesive layer 182 positioned on one surface of the base film layer 181 and the base film layer 181 as shown in FIG. 3. It is composed of a metal layer 184 located on one side of. The other surface of the base film layer 181 included in the first bonding area BDA1 may be protected by the upper passivation layer 183.

The nonbonding regions NBDA1 and NBDA2 are regions in which the anisotropic conductive film ACF is not formed. The non-bonding regions NBDA1 and NBDA2 are formed on at least one of the bonding regions BDA1 and BDA2, for example, at both outer sides of the first bonding region BDA1 and formed thicker than the thicknesses of the layers constituting the first bonding region BDA1. do. That is, the layers included in the non-bonding regions NBDA1 and NBDA2 are formed thicker than the first bonding region BDA1 since at least one layer is further included than the layers included in the first bonding region BDA1. To this end, the non-bonding regions NBDA1 and NBDA2 are formed of the adhesive layer 182 located on one surface of the base film layer 181 and the base film layer 181 and the dummy metal layer located on one surface of the adhesive layer 182 as shown in FIG. 4. 184 and a lower protective layer 185 positioned on one surface of the dummy metal layer 184. Here, the dummy metal layer 184 is formed of the same material as the metal layer 184. The other surface of the base film layer 181 included in the non-bonding regions NBDA1 and NBDA2 may also be protected by the upper protective layer 183. The dummy metal layer 184 included in the non-bonding areas NBDA1 and NBDA2 may have the same area or the same area as that of the non-bonding area NBDA1 and the other non-bonding area NBDA2.

The non-bonding areas NBDA1 and NBDA2 include alignment marks AL1 and AL2 formed at both ends of the first substrate pad group SPAD1. The alignment marks AL1 and AL2 are used to prevent misalignment between the pad group when the flexible circuit board and the panel are bonded to each other. The alignment marks AL1 and AL2 may also be formed on the second substrate pad group SPAD2.

The metal layer 184 included in the first bonding area BDA1 is included in the first substrate pad group SPAD1, which is connected to the signal wires SL. In contrast, the dummy metal layer 184 included in the non-bonding regions NBDA1 and NBDA2 is connected to a power supply line PL to which a low potential voltage, for example, the ground voltage GND is supplied.

If the thickness of the non-bonding areas NBDA1 and NBDA2 is formed to be thicker than the thickness of the first bonding area BDA1 as in the embodiment, the flexible circuit board may be attached or attached to the flexible circuit board and the panel using an anisotropic conductive film or the like. Cracks such as cracks or cracks in the non-bonding regions NBDA1 and NBDA2 are prevented. Accordingly, in the embodiment, the dummy metal layer 184 and the lower protective layer 185 are further formed in the non-bonding regions NBDA1 and NBDA2 to remove the step between the non-bonding regions NBDA1 and NBDA2 and the first bonding region BDA1. By doing so, it is possible to eliminate the crack problem of the flexible circuit board.

Hereinafter, a display device using a flexible circuit board according to an exemplary embodiment of the present invention will be described.

5 is a plan view illustrating a display device according to an embodiment of the present invention, FIG. 6 is a plan view of a flexible circuit board according to an embodiment of the present invention, and FIG. 7 is a part of the flexible circuit board shown in FIG. 6. 8 and 9 are sectional views of the region shown in FIG. 7, FIG. 10 is a sectional view of region A1-A2 shown in FIG. 5, and FIG. 11 is a sectional view of region B1-B2 shown in FIG. 5. to be.

5 to 11, the display device according to the exemplary embodiment of the present invention includes a panel 110, a driver 160, and a flexible circuit board 180.

The panel 110 includes a first substrate 110a and a second substrate 110b bonded by the adhesive member 140 formed in the non-display area NA. The display part AA including the subpixels SP arranged in a matrix form is formed on the first substrate 110a. The panel 110 is formed of an organic light emitting display panel including an organic light emitting diode or a liquid crystal display panel including a liquid crystal layer. When the panel 110 is formed of an organic light emitting display panel, the subpixel SP may include a switching transistor, a driving transistor, a capacitor, and an organic light emitting diode. In contrast, when the panel 110 is formed of a liquid crystal display panel, the sub-pixel SP may include a switching transistor, a capacitor, and a liquid crystal layer.

The driving unit 160 is formed on one surface of the first substrate 110a constituting the panel 110. The driver 160 may be mounted on one surface of the first substrate 110a as an integrated circuit (IC) including a timing driver, a scan driver, and a data driver. Alternatively, the driver 160 may be mounted on one surface of the first substrate 110a by one IC including a timing driver and a data driver, and the scan driver may be formed in the non-display area of the first substrate 110a. In contrast, the driver 160 is mounted on one surface of the first substrate 110a as a single IC including a data driver, the scan driver is formed in the non-display area of the first substrate 110a, and the timing driver is a flexible circuit. It may be mounted on the substrate 180.

The flexible circuit board 180 is attached to one surface of the first substrate 110a constituting the panel 110. The flexible circuit board includes mounting areas SMA, bonding areas BDA1 and DBA2, and non-bonding areas NBDA1 and NBDA2.

The mounting area SMA is an area in which the device U is mounted. In the drawings, the device U mounted in the mounting area SMA is only illustrated to facilitate understanding of the description, and the exemplary embodiment is not limited thereto. The mounting area SMA is formed thicker than the layers constituting the bonding areas BDA1 and BDA2. For example, adhesive layers, first metal layers, second metal layers, and protective layers may be disposed on upper and lower surfaces of the mounting area SMA based on the base film layer, but are not limited thereto.

The bonding areas BDA1 and BDA2 are areas attached to the panel 110 and the external substrate. At least two bonding areas BDA1 and BDA2 are disposed on the outside of the mounting area SMA and include a plurality of substrate pad groups SPAD1 and SPAD2, respectively. In the case of the first board pad group SPAD1 included in the first bonding area BDA1, the board is attached to the panel 110, and in the case of the second board pad group SPAD2 included in the second bonding area BDA2, an external board is provided. Is attached to. The first substrate pad group SPAD1 included in the first bonding area BDA1 and the second substrate pad group SPAD2 included in the second bonding area BDA2 are respectively formed by the anisotropic conductive film 170 or the like. It is attached to the substrate. At least one of the bonding areas BDA1 and BDA2, for example, the first bonding area BDA1 may include an adhesive layer 182 and an adhesive layer 182 disposed on one surface of the base film layer 181 and the base film layer 181 as shown in FIG. 8. It is composed of a metal layer 184 located on one side of. The other surface of the base film layer 181 included in the first bonding area BDA1 may be protected by the upper passivation layer 183.

The nonbonding regions NBDA1 and NBDA2 are regions in which the anisotropic conductive film ACF is not formed. The non-bonding regions NBDA1 and NBDA2 are formed on at least one of the bonding regions BDA1 and BDA2, for example, at both outer sides of the first bonding region BDA1 and formed thicker than the thicknesses of the layers constituting the first bonding region BDA1. do. That is, the layers included in the non-bonding regions NBDA1 and NBDA2 are formed thicker than the first bonding region BDA1 since at least one layer is further included than the layers included in the first bonding region BDA1. To this end, the non-bonding regions NBDA1 and NBDA2 are formed of an adhesive layer 182 located on one surface of the base film layer 181 and the base film layer 181 and a dummy metal layer located on one surface of the adhesive layer 182 as shown in FIG. 9. 184 and a lower protective layer 185 positioned on one surface of the dummy metal layer 184. Here, the dummy metal layer 184 is formed of the same material as the metal layer 184. The other surface of the base film layer 181 included in the non-bonding regions NBDA1 and NBDA2 may also be protected by the upper protective layer 183. The dummy metal layer 184 included in the non-bonding areas NBDA1 and NBDA2 may have the same area or the same area as that of the non-bonding area NBDA1 and the other non-bonding area NBDA2.

The non-bonding areas NBDA1 and NBDA2 include alignment marks AL1 and AL2 formed at both ends of the first substrate pad group SPAD1. The alignment marks AL1 and AL2 are used to prevent a misalignment problem between the pad group when the flexible circuit board and the panel are bonded to each other. The alignment marks AL1 and AL2 may also be formed on the second substrate pad group SPAD2.

The metal layer 184 included in the first bonding area BDA1 is included in the first substrate pad group SPAD1, which is connected to the signal wires SL. In contrast, the dummy metal layer 184 included in the non-bonding regions NBDA1 and NBDA2 is connected to a power supply line PL to which a low potential voltage, for example, the ground voltage GND is supplied.

Referring to FIG. 10, in which the flexible circuit board 180 and the panel 110 are attached to each other, the anisotropic conductive film 170 formed in the first bonding region BDA1 is illustrated in the flexible circuit board 180 and the panel 110. Attached). In more detail, anisotropy is positioned between the metal layer 184 constituting the first substrate pad group SPAD1 included in the first bonding region BDA1 and the panel pad group 165 included in the panel 110. It is attached by the conductive film 170. Although not shown, a surface treatment layer may be disposed on the surface of the metal layer 184 constituting the substrate pad group SPAD1 by a surface treatment process.

Referring to FIG. 11 where the flexible circuit board 180 and the panel 110 are attached to each other, the flexible circuit board 180 and the panel 110 may include dummy metal layers included in the non-bonding regions NBDA1 and NBDA2. 184 and the lower passivation layer 185 do not generate a step. In more detail, in the non-bonding regions NBDA1 and NBDA2, the dummy metal layer 184 and the lower protection may correspond to the thicknesses of the metal layer 184 and the anisotropic conductive film 170 positioned in the first bonding region BDA1. Since the layer 185 is located, the step difference between the first bonding area BDA1 and the non-bonding areas NBDA1 and NBDA2 is removed.

If the thickness of the non-bonding regions NBDA1 and NBDA2 is formed to be thicker than the thickness of the first bonding region BDA1, the flexible printed circuit board 180 and the panel 110 may be formed using the anisotropic conductive film 170. Cracks such as cracks or cracks in the non-bonding regions NBDA1 and NBDA2 of the flexible printed circuit board 180 are prevented when or after attaching. Accordingly, in the embodiment, the dummy metal layer 184 and the lower protective layer 185 are further formed in the non-bonding regions NBDA1 and NBDA2 to remove the step between the non-bonding regions NBDA1 and NBDA2 and the first bonding region BDA1. As a result, the crack problem of the flexible printed circuit board 180 can be eliminated.

Hereinafter, referring to Table 1, the test results of the driving state of the conventional structure and the embodiment structure during the driving test after bending the flexible circuit board 180 by the number of times will be described. In the following experimental results, it is considered that the flexible circuit board 180 is bent by 90 degrees in the forward and reverse directions.

In Table 1, the conventional structure is a structure in which the non-bonding regions NBDA1 and NBDA2 include only the base film layer 181, and in the embodiment, the non-bonding regions NBDA1 and NBDA2 include the base film layer 181 and the adhesive layer ( 182), the dummy metal layer 184 and the lower protective layer 185 was included in the experiment.

As shown in Table 1, the conventional structure is the panel 110 is driven only when the flexible circuit board 180 is bent and released about 10 times, while the structure of the embodiment is about 30 times the flexible circuit board 180 It was confirmed that the panel 110 can be driven in the normal state even when the bent and released.

Meanwhile, in the exemplary embodiment, the dummy metal layer 184 included in the flexible circuit board 180 is connected to the power supply line PL to which the ground voltage GND is supplied.

12 is a graph showing the EMI shielding of the conventional structure compared to the conventional structure.

As shown in FIG. 12, the dummy metal layer 184 is connected to the power supply line PL to which the ground voltage GND is supplied, thereby minimizing the influence of noise generated during signal transmission, thereby reducing EMI. Electro Magnetic Interference) has the effect of increasing the shielding function.

The present invention provides a flexible circuit board that can prevent cracking problems such as cracking or cracking around the bonding area by removing the step between the bonding area and the non-bonding area around the bonding area. It is effective to provide a display device. In addition, the present invention has the effect of providing a flexible circuit board and a display device using the same that can enhance the EMI shielding function.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all aspects. In addition, the scope of the present invention is shown by the claims below, rather than the above detailed description. Also, it is to be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention.

1 is a plan view of a flexible circuit board according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a portion of the flexible circuit board of FIG. 1.

3 and 4 are cross-sectional views of the region shown in FIG. 1.

5 is a plan view illustrating a display device according to an exemplary embodiment of the present invention.

6 is a plan view of a flexible circuit board according to an embodiment of the present invention.

FIG. 7 is an enlarged view of a portion of the flexible circuit board of FIG. 6.

8 and 9 are cross-sectional views of the region shown in FIG.

FIG. 10 is a sectional view of the region A1-A2 shown in FIG. 5; FIG.

FIG. 11 is a sectional view of region B1-B2 shown in FIG. 5; FIG.

Figure 12 is an EMI shield of the embodiment structure compared to the conventional structure.

<Explanation of symbols on main parts of the drawings>

SMA: mounting area BDA1, BDA2: bonding area

NBDA1, NBDA2: non-bonding area SPAD1, SPAD2: substrate pad group

110: panel 160: drive unit

180: flexible circuit board 181: base film layer

182: adhesive layer 184: metal layer and dummy metal layer

183: upper protective layer 185: lower protective layer

Claims (10)

A mounting area in which the device is mounted; At least two bonding areas disposed on an outer side of the mounting area, each bonding area including a plurality of substrate pad groups; And And a non-bonding region positioned on both outer sides of at least one of the bonding regions and formed to be thicker than a thickness of the layers constituting the bonding region. The method of claim 1, Layers included in the non-bonding region, At least one layer is further included than the layers included in the bonding region. The method of claim 1, The bonding region includes a base film layer, an adhesive layer located on one surface of the base film layer, and a metal layer located on one surface of the adhesive layer, The non-bonding region may include a dummy metal layer formed of the same material as the base film layer, the adhesive layer, and the metal layer, and a protective layer on one surface of the dummy metal layer. The method of claim 3, The dummy metal layer, A flexible printed circuit board, characterized in that connected to a wiring to which a low potential voltage is supplied. The method of claim 1, A flexible printed circuit board positioned in the non-bonding region and including alignment marks formed at both ends of the substrate pad group. Display panel; A plurality of panel pad groups formed on the display panel; And A mounting area in which the device is mounted, a bonding area having at least two parts positioned separately from the outside of the mounting area, and having a plurality of pad groups, and layers positioned at both outer peripheries of at least one of the bonding areas and constituting the bonding area; A display device comprising a flexible circuit board including a non-bonding region formed thicker than the thickness of the. The method of claim 6, Layers included in the non-bonding region, And at least one layer more than the layers included in the bonding area. The method of claim 6, The bonding region includes a base film layer, an adhesive layer located on one surface of the base film layer, and a metal layer located on one surface of the adhesive layer, The non-bonding region may include a dummy metal layer formed of the same material as the base film layer, the adhesive layer, and the metal layer, and a protective layer on one surface of the dummy metal layer. The method of claim 8, The dummy metal layer, A display device, characterized in that connected to a wiring to which a low potential voltage is supplied. The method of claim 6, And an alignment mark positioned in the non-bonding region and formed at both ends of the substrate pad group.

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