KR20080018718A - Liquid crystal display - Google Patents

Abstract

A liquid crystal display device is provided to form a ground layer at a flexible printed circuit board to reduce electromagnetic wave interference. A liquid crystal panel(133) displays images. A first printed circuit board(136) is connected to one side of the liquid crystal panel by a TCP(Tape Carrier Package). A flexible printed circuit film includes a base film, a wiring pattern having a plurality of signal lines formed on the base film, an insulator passivation film formed on the wiring pattern, and a ground layer formed on the insulator passivation film and electrically connected to a ground line of the wiring pattern. A second printed circuit board(137) is connected to the first printed circuit board by the flexible printed circuit film. A bottom chassis(170) contains the liquid crystal panel. A conductive tape is attached to the flexible printed circuit film and a lower container at the same time, and is electrically connected to the ground layer of the flexible printed circuit film.

Description

Liquid crystal display

1 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 2 is a rear perspective view of the liquid crystal display of FIG. 1.

3 is a cross-sectional view taken along the line III-III ′ after the liquid crystal display of FIG. 2 is assembled.

FIG. 4 is an enlarged view of portion A of the liquid crystal display of FIG. 1.

5 is a cross-sectional view taken along the line VV ′ of the flexible printed circuit film of FIG. 4.

(Explanation of symbols for the main parts of the drawing)

100: liquid crystal display device 130: liquid crystal panel assembly

133: liquid crystal panel 136: first printed circuit board

137: second printed circuit board 140: flexible printed circuit film

141: base film 142: wiring pattern

145: ground layer 147: insulating protective film

150: backlight assembly 160: mold frame

170: bottom chassis 180: top chassis

190: shield case 200: conductive tape

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device capable of reducing electromagnetic interference characteristics.

In recent years, liquid crystal displays have been in the spotlight as display means.

The liquid crystal display device includes a liquid crystal panel including two display panels and a liquid crystal layer injected between the display panels, and displays information by using light modulation by a change in optical characteristics of the liquid crystal.

In such a liquid crystal display device, a printed circuit board (PCB) is electrically connected to a liquid crystal panel by a tape carrier package (TCP), and electrical signals generated from the printed circuit board are transferred through the TPC. It is provided by the panel.

In recent years, as the size of the liquid crystal display device increases, the printed circuit board is separated into a data printed circuit board and a control printed circuit board, respectively. Here, the data printed circuit board is connected by the liquid crystal panel and the TPC, and the control printed circuit board is connected through the data printed circuit board and the flexible printed circuit film.

Here, the flexible printed circuit film has many lines formed in a very narrow width for the electrical connection between the data printed circuit board and the control printed circuit board. In addition, since the driving elements mounted on the data printed circuit board and the control printed circuit board are operated by high frequency, they are the source of electromagnetic interference (Electromagnetic Interference) or electrostatic discharge (ESD). In addition, the electromagnetic waves not only interfere with electrical signals transmitted to the liquid crystal panel, but also are emitted to the outside of the liquid crystal display to cause malfunction of other peripheral devices.

Therefore, a method for reducing the interference characteristics caused by electromagnetic waves is required.

An object of the present invention is to provide a liquid crystal display device that can reduce the interference of electromagnetic waves.

The technical problem of the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a liquid crystal display device including: a liquid crystal panel displaying an image; a first printed circuit board connected to one side of the liquid crystal panel by TCP; A flexible printed circuit comprising a film, a wiring pattern having a plurality of signal lines formed on the base film, an insulating protective film formed on the wiring pattern, and a ground layer formed on the insulating protective film and electrically connected to the ground wiring of the wiring pattern. The flexible printed circuit film is simultaneously attached to the film, the second printed circuit board connected by the first printed circuit board and the flexible printed circuit film, the bottom chassis which houses the liquid crystal panel, the flexible printed circuit film and the lower housing. And a conductive tape electrically connected with the ground layer of the substrate.

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Examples of the liquid crystal display used in the present invention include a portable multimedia player (PMP), a personal digital assistant (PDA), a portable digital player (DVD) player, a mobile phone, a notebook computer, and a digital TV. For convenience of explanation, the liquid crystal display of the present invention will be described using a TV. However, the present invention is not limited thereto and may be applied to various liquid crystal display devices.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention, FIG. 2 is a rear perspective view of the liquid crystal display of FIG. 1, and FIG. 3 is III-III after the liquid crystal display of FIG. 2 is assembled. It is a cross-sectional view cut in line.

First, referring to FIG. 1, the liquid crystal display 100 largely includes a liquid crystal panel assembly 130, a backlight assembly 150, a bottom chassis 170, a top chassis 180, a shield case 190, and the like. It is configured by.

The liquid crystal panel assembly 130 includes a liquid crystal panel 133, TPCs 134 and 135, first and second printed circuit boards 137, a flexible printed circuit film 140, and the like.

The liquid crystal panel 133 displays an image and includes a first display panel 131, a second display panel 132, and a liquid crystal layer (not shown) interposed between the two display panels 131 and 132. The first display panel 131 may include a plurality of gate lines having a predetermined interval and extending in the first direction, and data lines, gate lines, and data lines extending in the second direction so as to intersect the gate line and arranged at regular intervals. In the defined pixel region, a thin film transistor is formed to be switched by a signal of a pixel electrode and a gate line formed in a matrix to transfer a signal of a data line to each pixel electrode.

In addition, the second display panel 132 is formed with a light blocking pattern for blocking light in portions other than the pixel area, an RGB color filter pattern for expressing color colors, and a common electrode for implementing an image.

The first display panel 131 and the second display panel 132 are bonded to each other by being kept at regular intervals by a spacer or the like, wherein the liquid crystal layer having optical anisotropy is formed between the first display panel 131 and the second display panel 132. Is formed.

The first printed circuit board 136 is electrically connected to one side of the liquid crystal panel 133 by TPCs 134 and 135. Here, a driving IC for driving the liquid crystal panel 133 is mounted in the center portion of the TPCs 134 and 135.

The TPCs 134 and 135 are connected to gate lines of the first display panel 131 and connected to data lines of the gate TPC 134 and the first display panel 131 to provide driving and control signals. It may be configured to include a data PC 135 for providing a signal. In this case, the data PC 135 is electrically connected to the first printed circuit board 136, and the first printed circuit board 136 also includes a plurality of electronic components that generate driving and control signals of the liquid crystal panel 133. May be mounted.

The second printed circuit board 137 is positioned adjacent to the first printed circuit board 136 and electrically connected to the first printed circuit board 136 by the flexible printed circuit film 140. In addition, similar to the first printed circuit board 136, the second printed circuit board 137 includes a plurality of electronic components that generate driving and control signals of the liquid crystal panel 133. Therefore, the driving and control signals of the liquid crystal panel 133 generated in the second printed circuit board 137 are provided to the first printed circuit board 136 through the flexible printed circuit film 140, and the liquid crystal panel 133 The driving and control signals of are provided to the liquid crystal panel 133 through a data PC connected to the first printed circuit board 136.

Here, the plurality of electronic components mounted on the first and second printed circuit boards 136 and 137 are mostly operated by high frequency signals, which causes electromagnetic waves (Electro Magnetic Interference). In order to solve this problem, a method of grounding the first and second printed circuit boards 136 and 137 to a storage container, for example, the top / bottom chassis 170 or the like, may be used.

The flexible printed circuit film 140 electrically connects the first printed circuit board 136 and the second printed circuit board 137. The flexible printed circuit film 140 is formed by forming a conductor pattern on a film having flexibility and insulation, for example, a base film having a polyimide material. The flexible printed circuit film 140 may include a plurality of signal lines capable of transmitting electrical signals. A wiring pattern configured to constitute a predetermined circuit, a connection pad connected to the outside, and the like. In addition, the flexible printed circuit film 140 may include a predetermined ground layer to reduce electromagnetic interference.

Hereinafter, the flexible printed circuit film will be described in detail with reference to FIGS. 4 and 5.

4 is an enlarged view of a portion A of the liquid crystal display of FIG. 1, and FIG. 5 is a cross-sectional view taken along the line VV ′ of the flexible printed circuit film of FIG. 4.

First, referring to FIG. 4, the flexible printed circuit film 140 is formed by forming a conductor pattern on one surface of a film having flexibility and insulation, for example, a base film 141 having a polyimide material. A wiring pattern 142 constituting a predetermined circuit with a plurality of signal lines capable of transmitting a signal, and connecting portions 143 and 144 formed at one end and the other end of the base film 141 around the wiring pattern 142, respectively. It consists of a structure comprising a.

In addition, the insulating protection film 147 is formed on the wiring pattern 142, and the insulating protection film 147 further includes a ground layer 145 electrically connected to the ground wire of the wiring pattern 142.

The wiring pattern 142 may generally use a metal material such as copper foil (Cu) or aluminum (Al), and preferably, may be formed by plating tin, gold, nickel, or solder on the surface of the copper foil. The wiring pattern 142 may be formed to a thickness of about 5 ~ 20㎛.

Here, the copper foil, which is an example of the wiring pattern 142, may be formed by casting, laminating, electroplating, and the like. Here, casting is a method of spraying a liquid base film on a rolled copper foil to perform thermal curing, and laminating is a method of placing a rolled copper foil on a base film and thermocompressing it. In addition, electroplating is a method of forming a copper foil by depositing a copper seed layer on the base film and putting the base film in an electrolyte in which copper is melted and flowing electricity. Here, the wiring patterned on the copper foil may be formed to configure a predetermined circuit by selectively etching the copper foil by performing a photo / etching process on the copper foil.

An insulating passivation layer 147 may be formed on the wiring pattern 142. The insulating protective film 147 is formed to protect the wiring pattern 142 from external impact or corrosive material. For example, a solder resist may be used as the insulating protective film 147.

The connecting portions 143 and 144 formed at both ends of the base film 141 are portions for electrically connecting with the outside. The connection parts 143 and 144 may be formed on the other surface of the base film 141 on which the wiring pattern 142 is formed, and formed on one end of the base film 141 to form the first printed circuit board 136. And a second connection pad 143 formed at the other end of the first connection pad 144 and the base film 141 to be connected to the second printed circuit board 137. Here, the first and second connection pads 143 and 144 and the first and second printed circuit boards 136 and 137 may be, for example, a connector 138, soldering or anisotropic conductive film. Film; ACF) or the like. The flexible printed circuit film 140 according to the present exemplary embodiment uses a connection method using a soldering method with the pads 136a of the first printed circuit board 136, and with the pads 137a of the second printed circuit board 137. The connection method using the connector 138 is demonstrated to an example.

The ground layer 145 is formed on the top surface of the insulating protective film 147. The ground layer 145 may be electrically connected to the ground wire of the wiring pattern 142, and the connecting portions 143 and 144 formed at both ends of the base film 141, that is, the first connection pad 144 and the second connection may be formed. It may be formed over the entire surface of the insulating protective film 147 except for the pad 143.

Referring to FIG. 5, as described above, the flexible printed circuit film 140 may include a base film 141, a wiring pattern 142, an insulating protective film 147, and a ground layer 145. The ground layer 145 may be formed on the top surface of the insulating protective layer 147. The ground layer 145 may be formed by the same process as the wiring pattern 142, for example, a laminating method.

In addition, the ground layer 145 may be electrically connected to the ground wire of the wiring pattern 142, where a part of the insulating protection layer 147 is partially removed, for example, a via is formed on the insulating protection layer 147. The ground layer 145 and the ground line of the wiring pattern 142 may be in contact with each other (B of FIG. 5). As a result, the ground area of the flexible printed circuit film 140 may be increased to reduce electromagnetic interference by grounding electromagnetic waves emitted to the outside through the wiring pattern 142 through the ground layer 145.

Referring back to FIGS. 1 to 3, the above-described first and second printed circuit boards 136 and 137 and the flexible printed circuit film 140 connecting them to each other may be bent and disposed at the rear surface of the bottom chassis 170. Can be.

2 and 3, the first printed circuit board 136 may be coupled / fixed to one side wall of the bottom chassis 170, and the second printed circuit board 137 may be located at the bottom chassis 170. Can be positioned on the back of the coupling / fixed.

In addition, the flexible printed circuit film 140 is connected to the first printed circuit board 136 and is bent to the rear surface of the bottom chassis 170 along one side wall of the bottom chassis 170 so as to be connected to the second printed circuit board 137. Can be connected. In this case, the ground layer 145 of the flexible printed circuit film 140 may be exposed to the outside by being positioned on the outer surface of the bent flexible printed circuit film 140, that is, the outer surface facing the bottom chassis 170.

Here, a predetermined conductive tape 200 may be attached to the ground layer of the flexible printed circuit film 140 described above. Specifically, the flexible printed circuit film 140 is bent to the rear surface of the bottom chassis 170 along one side wall of the bottom chassis 170, and the ground layer is located on the outer surface of the flexible printed circuit film 140 to the outside. The exposed conductive tape 200 may be attached to the ground layer. In this case, the conductive tape 200 may be a metal material, for example, an aluminum conductive tape 200.

In addition, the conductive tape 200 may be simultaneously attached to the flexible printed circuit film 140 and the bottom chassis 170. In detail, the conductive tape 200 may extend from the rear surface of the bottom chassis 170 to the flexible printed circuit film 140, that is, the ground layer 145 of the flexible printed circuit film 140 exposed to the outside. In this case, the conductive tape 200 may be in contact with the ground layer 145 of the flexible printed circuit film 140, whereby electromagnetic waves emitted from the flexible printed circuit film 140 may be bottomed through the conductive tape 200. 170 can be grounded.

In addition, the conductive tape 200 may be attached to the flexible printed circuit film 140, the bottom chassis 170, and the top chassis 180 at the same time. Specifically, the top chassis 180 descends from the front surface of the liquid crystal panel 133 to be coupled to the bottom chassis 170, and covers the first printed circuit board 136 coupled / fixed to one side wall of the bottom chassis 170. can do. As described above, the flexible printed circuit film 140 may be exposed to the outside by the ground layer 145 located outside, and the conductive tape 200 may be attached to the exposed flexible printed circuit film 140. have. The conductive tape 200 may cover the ground layer 145 of the flexible printed circuit film 140 from the rear surface of the bottom chassis 170 and extend to one side wall of the top chassis 180. In this case, the conductive tape 200 may be in contact with the ground layer 145 of the flexible printed circuit film 140, whereby the electromagnetic waves emitted from the flexible printed circuit film 140 may pass through the top chassis 180 through the conductive tape 200. ) And the bottom chassis 170 can be grounded.

In addition, the conductive tape 200 may be attached to the flexible printed circuit film 140, the bottom chassis 170, the top chassis 180, and the shield case 190 simultaneously. In more detail, the shield case 190 may be coupled / fixed to the rear surface of the bottom chassis 170 and may cover the second printed circuit board 137 to protect it from the outside. The shield case 190 may be formed, for example, in a rectangular frame shape consisting of sidewalls and a bottom surface, a predetermined open area may be formed on one sidewall, and the flexible printed circuit film 140 may be formed through the open area. ) May be combined with the second printed circuit board 137. In addition, the conductive tape 200 attached to the flexible printed circuit film 140 exposed to the outside covers the shield case 190 and the ground layer 145 of the flexible printed circuit film 140 from the rear surface of the bottom chassis 170. And extends to one side wall of the top chassis 180. Here, the conductive tape 200 preferably covers the open area of the shield case 190. In addition, the conductive tape 200 may be in contact with the ground layer 145 of the flexible printed circuit film 140, whereby the electromagnetic waves emitted from the flexible printed circuit film 140 may pass through the top chassis 180 through the conductive tape 200. ), The bottom chassis 170 and the shield case 190 may be grounded.

The top chassis 180, the bottom chassis 170, and the shield case 190 may be formed of a metal material, and for example, aluminum or an aluminum alloy may be used.

Referring back to FIG. 1, the backlight assembly 150 that provides light to the liquid crystal panel 133 is positioned below the liquid crystal panel assembly 130 having the above-described structure. The backlight assembly 150 may include a light source unit 153, a light guide plate 152, a reflective sheet 154, and optical sheets 151.

The light source unit 153 is disposed on at least one side of the light guide plate 152, and includes a light source and a light source cover covering the light source. The light source may be a line light source such as a Cold Cathode Fluorescent Lamp (CCFL) or a Hot Cathode Fluorescent Lamp (HCFL), and a point light source such as a light emitting diode (LED). It may be.

On the other hand, the light source unit 153 may be disposed on the long side or the short side of the rectangular light guide plate 152, two may be disposed on the neighboring side or the opposite side. In FIG. 1, one light source unit 153 is disposed on a long side of the light guide plate 152 as an example.

The light guide plate 152 has a rectangular shape and serves to guide light emitted from the light source unit 153 toward the upper side of the backlight assembly 150, that is, the liquid crystal panel 133. The light guide plate 152 may be formed of a material having high refractive index and high transmittance, for example, polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene (PE), or the like.

In addition, a scattering pattern for scattering light is formed on the bottom of the light guide plate 152 to guide light incident from the side surface of the light guide plate 152 to the upper side. The scattering pattern may be formed by applying a scattering material to the bottom surface of the light guide plate 152 and patterning the scattering material, or by applying a predetermined curvature to the bottom surface of the light guide plate 152, but is not limited thereto.

The reflective sheet 154 is disposed under the light guide plate 152. The reflective sheet 154 reflects the light leaked through the bottom of the light guide plate 152 to the lower side of the light guide plate 152 again to the upper side of the light guide plate 152 to increase the brightness of the backlight assembly 150, and Light is uniformly emitted to the upper side of 152).

As the reflective sheet 154, a material having good elasticity, excellent light reflection, and thinness may be used. For example, a polyethylene terephtalate (PET) having a thickness of 0.01 mm to 5 mm may be used, but is not limited thereto. In addition, if necessary, a thin film having good elasticity may be used by coating a reflective film to increase light reflection.

The optical sheets 151 are disposed on the light guide plate 152. The optical sheets 151 allow the light guided by the light guide plate 152 to be uniformly irradiated onto the upper side of the backlight assembly, for example, by selectively stacking optical sheets such as one or more diffusion sheets, prism sheets, or protective sheets. It is done. At this time, only one optical sheet may be disposed, and a plurality of identical optical sheets may be disposed. In addition, the stacking order of the optical sheet may be variously modified in a range of increasing the uniformity of light.

The optical sheets 151 may be formed of a transparent resin such as an acrylic resin, a polyurethane resin, or a silicone resin.

The mold frame 160 has a locking step formed along the sidewall, and serves to support the liquid crystal panel assembly 130 described above, and is received in the bottom chassis 170.

The bottom chassis 170 may have a rectangular shape, and sidewalls are formed along edges of the upper surface to accommodate the above-described backlight assembly 150 and the mold frame 160 in the sidewalls.

The bottom chassis 170 may be coupled to the top chassis 180 through hook coupling (not shown) and / or screw coupling 195. In addition, the combination of the top chassis 180 and the bottom chassis 170 may be modified in various forms.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

As described above, according to the liquid crystal display device according to the present invention, by providing the ground layer in the flexible printed circuit film, it is possible to reduce the interference phenomenon of electromagnetic waves.

Claims (7)

A liquid crystal panel displaying an image; A first printed circuit board connected to one side of the liquid crystal panel by TCP; A base film, a wiring pattern having a plurality of signal lines formed on the base film, an insulating protective film formed on the wiring pattern, and a ground layer formed on the insulating protective film and electrically connected to the ground wiring of the wiring pattern. A flexible printed circuit film comprising; A second printed circuit board connected by the first printed circuit board and the flexible printed circuit film; A bottom chassis accommodating the liquid crystal panel; And And a conductive tape attached to the flexible printed circuit film and the lower receiving container at the same time and electrically connected to the ground layer of the flexible printed circuit film. According to claim 1, And the ground layer is electrically connected to the ground line by partially removing the insulating protective layer. According to claim 1, The flexible printed circuit film further includes connecting portions formed at both ends of the base film and connected to the first and second printed circuit boards, The ground layer is formed on the entire surface of the insulating protective film except for the connection portion. According to claim 1, The ground layer is formed of the same material as the wiring pattern. According to claim 1, The flexible printed circuit film is bent to the rear surface of the bottom chassis along one side wall of the bottom chassis, And the conductive tape extends from the rear surface of the bottom chassis to the flexible printed circuit film. According to claim 1, A top chassis configured to receive the liquid crystal panel in combination with the bottom chassis from a front surface of the liquid crystal panel, And the conductive tape is attached to the top chassis, the bottom chassis, and the ground layer of the flexible printed circuit film simultaneously. The method of claim 6, A shield case coupled to a rear surface of the bottom chassis to cover the second printed circuit board, And the conductive tape is attached to the top chassis, the bottom chassis, the shield case, and the ground layer of the flexible printed circuit film simultaneously.

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