KR20070041032A - Printed circuit board and liquid crystal display including the same - Google Patents

Abstract

Provided are a printed circuit board and a liquid crystal display including the same capable of reducing manufacturing costs by reducing the number of components to be mounted. The printed circuit board includes an insulating substrate, a circuit pattern for forming a predetermined circuit on the insulating substrate, and a plurality of first pads electrically connected to the circuit pattern. And a second pad group having a first pad group to be mounted and a plurality of second pads electrically connected to a circuit pattern, and shorted between the second pads.

Printed circuit board, liquid crystal display, pad

Description

Printed circuit board and liquid crystal display including the same

1 is a partial perspective view of a liquid crystal panel assembly having a printed circuit board according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view of the printed circuit board of FIG. 1.

3 is an exploded perspective view of a liquid crystal display device in which the liquid crystal panel assembly of FIG. 1 is used.

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

100: liquid crystal panel assembly 10: liquid crystal panel

11: first display panel 13: second display panel

15: gate line 16: data line

20: gate TC 25: gate drive IC

30: data TC 35: data drive IC

40: printed circuit board 41: insulated substrate

43: circuit pattern 44: short wiring pattern

45: first pad group 47: second pad group

45a, 45b: first pad 47a, 47b: second pad

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board and a liquid crystal display including the same, and more particularly, to a printed circuit board having a reduced number of components to be mounted and a liquid crystal display including the same.

As the information society develops, the demand for display devices is changing in various forms, and in recent years, liquid crystal displays, organic luminescent displays, and plasma display panels have been developed. Various flat panel displays have been developed and used in various fields.

Among the flat panel display devices which are most widely used, a liquid crystal display device having excellent image quality, light weight, thinness, and low power consumption may be used. The liquid crystal display includes a liquid crystal panel including two display panels on which electrodes are formed and a liquid crystal layer interposed therebetween, and applies a voltage to the electrodes to rearrange the liquid crystal molecules of the liquid crystal layer to determine the amount of light transmitted. It is a display device to adjust. Since the liquid crystal display is a non-light emitting device, it cannot be used where there is no light. In order to compensate for these disadvantages and to enable use even in the dark, a backlight assembly for irradiating uniform light to the liquid crystal panel is mounted.

In addition, a printed circuit board is provided outside the liquid crystal panel to generate various control signals, data signals, and the like for controlling the image displayed on the liquid crystal panel by an electrical signal. The printed circuit board is electrically connected with the liquid crystal panel by, for example, a tape carrier package.

Various electronic components are mounted on the printed circuit board for driving and controlling the liquid crystal panel. In addition, a resistor having a value of 0 ohms is mounted at a portion where the pattern may be shorted. This is to speed up the process when the specification changes according to the development evaluation of the printed circuit board or the customer's request, and the number is usually about 10-20.

However, as the resistor having a value of 0 ohm is mounted, the number of components increases, and thus, a manufacturing cost increases.

It is an object of the present invention to provide a printed circuit board with a reduced number of components to be mounted.

Another object of the present invention is to provide a liquid crystal display device including the printed circuit board.

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

A printed circuit board according to an embodiment of the present invention for achieving the above technical problem, an insulating substrate, a circuit pattern for forming a predetermined circuit on the insulating substrate, and a plurality of first pads electrically connected to the circuit pattern A first pad group opened between the first pads to mount various electronic components, and a plurality of second pads electrically connected to the circuit pattern, and a second pad group shorted between the second pads. It includes.

The liquid crystal display according to the exemplary embodiment of the present invention for achieving the another technical problem includes such a printed circuit board.

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. 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 a partial perspective view of a liquid crystal panel assembly having a printed circuit board according to an embodiment of the present invention, and FIG. 2 is a partially enlarged view of the printed circuit board of FIG. 1.

As shown in FIG. 1 and FIG. 2, the printed circuit board 40 is electrically connected to the liquid crystal panel 10 by Tape Carrier Package (TCP) 20, 30.

In addition, the liquid crystal panel 10 displays an image, and includes a first display panel 11 including a thin film transistor and a pixel electrode, a second display panel 13 including a color filter and a common electrode, and two display panels 11. 13) a liquid crystal layer (not shown) formed between.

The first display panel 11 includes a plurality of gate lines 15 extending in a first direction at regular intervals and a plurality of data extending in a second direction so as to intersect the gate lines 15 and arranged at regular intervals. Line 16 is provided. In addition, the data line 16 is switched by a pixel electrode formed in a matrix form in a predetermined region defined by the gate line 15 and the data line 16 and a signal of the gate line 15, and is connected to the pixel electrode formed in the pixel region. It includes a thin film transistor for transmitting a signal.

The second display panel 13 is provided with a black matrix for blocking light in portions other than the pixel area, a color filter for expressing RGB color color, and a common electrode for implementing an image.

The first display panel 11 and the second display panel 13 are bonded to each other by a sealant, frit glass, or the like in a state where a constant distance is maintained.

In addition, a liquid crystal layer having optical anisotropy is formed between the first display panel 11 and the second display panel 13.

A printed circuit board (PCB) 40 is electrically connected to one side of the liquid crystal panel 10 having such a structure by the TPCs 20 and 30. In addition, driving ICs 25 and 35 for driving the liquid crystal panel 10 are mounted at the centers of the TPCs 20 and 30.

Here, the TPCs 20 and 30 are connected to the gate line 15 of the first display panel 11 to apply the driving and control signals, and the data lines 16 of the first display panel 11. ) And a data PC 30 to which driving and control signals are applied.

2, various electronic components 50 are mounted on the printed circuit board 40 to receive image signals and various control signals from the outside and generate driving and control signals of the liquid crystal panel 10.

The printed circuit board 40 includes a circuit pattern 43, a first pad group 45, and a second pad group 47. The circuit pattern 43 also includes a short wiring pattern 44.

Here, the first and second pad groups 45 and 47 are electrically connected to the circuit pattern 43, and the first pads 45a and 45b on which the electronic components are mounted, and the electronic components are not mounted. Second pads 47a and 47b shorted by the short wiring pattern 44 are included.

Briefly looking at the manufacturing method of the printed circuit board 40 as follows.

First, the copper thin film is extruded on the insulating substrate 41 at a predetermined temperature and pressure to form a desired thickness. At this time, for example, an epoxy resin plate or the like is used as the insulating substrate 41, and the copper thin film is formed to a thickness of approximately 10 to 20 μm.

Next, the copper thin film is patterned through a normal photolithography process to form a predetermined circuit pattern 43, a short wiring pattern 44, a first pad group 45, and a second pad group 47. This forming method uses, for example, a dry film, which is composed of three layers of a cover film, a photoresist film and a mylar film, and the layer which substantially serves as a resist is a photoresist film layer. . A method of forming the circuit pattern 43, the short wiring pattern 44, the first pad group 45, and the second pad group 47 using the dry film will be briefly described as follows.

First, the cover film of the dry film is peeled off and then coated on the insulating substrate 41 on which the copper thin film is formed. This is called lamination. Next, after the circuit pattern 43, the short wiring pattern 44, the first pad group 45 and the second pad group 47 are adhered to the artwork film printed thereon, ultraviolet rays are irradiated. At this time, the black portion on which the circuit pattern 43, the short wiring pattern 44, the first pad group 45, and the second pad group 47 of the artwork film is printed does not pass ultraviolet rays, and other portions thereof. The ultraviolet rays are transmitted to cure the dry film. Subsequently, when the insulating substrate 41 is immersed in the developer, the uncured dry film portion is removed, and the hardened dry film remains to complete the resist pattern. At this time, sodium carbonate or potassium carbonate is used as the developer. Subsequent etching is performed so that the portion where the etching resist pattern is formed is not etched and only the copper foil of the portion remains, and when the etching resist is removed again, the circuit pattern 43, the short wiring pattern 44, and the first The printed circuit board 40 on which the pad group 45 and the second pad group 47 are formed is made. Here, a stripper is used to remove the etching resist, and sodium hydroxide or potassium hydroxide is usually used.

Thus, the solder masking process is performed on the printed circuit board 40 in which the circuit pattern 43, the short wiring pattern 44, the 1st pad group 45, and the 2nd pad group 47 were formed.

Here, solder masking means that when mounting an electronic component on a printed circuit board 40, the surface of the printed circuit board 40 may be exposed to molten lead, which may cause unwanted solder bridges. Surface of the insulating substrate 41 including the circuit pattern 43 and the short wiring pattern 44 except for the parts except the periphery in which the component is to be mounted, that is, the first pad group 45 and the second pad group 47. The process of coating the green film on the surface. The solder masking process may be screen printing or the like.

Next, nickel / gold (Ni / Au) plating is performed on portions of the first pads 45a and 45b and the second pads 47a and 47b of the first pad group 45 and the second pad group 47. This is because the contact between the electronic component 50 and the first and second pads 45a, 45b, 47a, 47b when the electronic components are mounted on the first pads 45a, 45b and the second pads 47a, 47b. At this time, the thickness of the nickel layer is about 2.5㎛, the thickness of the gold layer is formed to about 0.5 ~ 1.5㎛.

Finally, a silk screen process is performed to distinguish each electronic component, an electrode mark, and a part name mark, and the printed circuit board 40 is completed through a cleaning and inspection process.

The printed circuit board 40 completed by the above-described process includes a circuit pattern 43, a short wiring pattern 44, a first pad group 45, a second pad group 47, and the like. At this time, the first pad group 45 and the second pad group 47 are substantially composed of first pads 45a and 45b on which electronic components are mounted and second pads 47a and 47b on which electronic components are not mounted. do.

The circuit pattern 43 includes a short wiring pattern 44 for shorting the second pads 47a and 47b. The circuit pattern 43 and the short wiring pattern 44 form a predetermined circuit by patterning a copper thin film formed on the insulating substrate 41, and perform solder masking to prevent a short circuit in which solder flows during the soldering process. A protective layer is prevented.

The protective layer is formed by screen printing using a solder resist, and the insulating substrate on which the circuit pattern 43 and the short wiring pattern 44 except for the first pad group 45 and the second pad group 47 are formed is formed. It is formed on the surface of 41.

In addition, the circuit pattern 43 may be formed inside the insulating substrate 41. In this case, the printed circuit board 40 may be formed by stacking the insulating substrate 41 on which the circuit patterns 43 are formed.

The first pad group 45 and the second pad group 47 are electrically connected to the circuit pattern 43, and include the first pads 45a and 45b and the second pads 47a and 47b.

The first pads 45a and 45b include a plurality of pads electrically connected to the circuit pattern 43, and various electronic components 50 required for driving the liquid crystal panel 10 are mounted. In addition, the first pads 45a and 45b are spaced apart from each other and are open. The separation distances of the first pads 45a and 45b are changed according to the size of the electronic component 50 to be mounted.

Like the first pads 45a and 45b, the second pads 47a and 47b are formed of a plurality of pads electrically connected to the circuit pattern 43. However, the electronic component 50 is not mounted on the second pads 47a and 47b, and the second pads 47a and 47b are shorted by the short wiring pattern 44.

The second pads 47a and 47b apply a predetermined signal during the test of the printed circuit board 40 or serve to connect circuit parts having different functions configured in the printed circuit board 40. For example, when the printed circuit board 40 is completed, the first pads 45a and 45b have various electronic components 50 mounted thereon and perform operations of the respective portions by the circuit pattern 43. However, the second pads 47a and 47b are in a state in which the electronic component 50 is not mounted and is only shorted by the short wiring pattern 44. At this time, in order to apply a predetermined signal for the test of the printed circuit board 40, the shorted second pads 47a and 47b are opened to each terminal, that is, to each pad portion of the second pads 47a and 47b. Apply a signal. As a method of opening between the second pads 47a and 47b, a method of cutting and opening the short wiring pattern 44 in which the second pads 47a and 47b are shorted is used.

In addition, the first and second pads 45a, 45b, 47a, and 47b are nickel / gold plated as described above to improve contact with the electronic component 50, and a plurality of pads on the printed circuit board 40 are provided. Is formed.

3 is an exploded perspective view of a liquid crystal display device in which the liquid crystal panel assembly of FIG. 1 is used.

Referring to FIG. 3, the liquid crystal display device 300 includes a liquid crystal panel assembly 100 and a backlight assembly 200.

The liquid crystal panel assembly 100 includes a liquid crystal panel 10, TPCs 20 and 30, a printed circuit board 40, and the like, and detailed descriptions of the respective components are described above with reference to FIGS. 1 and 2. same.

The backlight assembly 200 that provides light to the liquid crystal panel 10 is positioned below the liquid crystal panel assembly 100.

The backlight assembly 200 includes an upper receiving container 240, an optical sheet 220, a lamp unit 210, a reflecting plate 230, a lower receiving container 250, and the like.

The lamp unit 210 may include a lamp 215 and a lamp holder 217, wherein the lamp 215 may include a cold cathode fluorescent lamp (CCFL) and an external electrode fluorescent lamp (CFL). EEFL) and Light Emitting Diode (LED) are used. In the present embodiment, the external electrode fluorescent lamp 215 has been described as an example, but the present invention is not limited thereto, and all known lamps may be used.

The lamp 215 is an external electrode fluorescent lamp 215 having a rod-shaped lamp tube 213 and external electrodes 211 formed at both ends of the lamp tube 213. In addition, a discharge gas is injected into the lamp tube 213, and the external electrode 211 is formed of a conductive material to surround the outside of the lamp tube 213. The external electrode fluorescent lamp 215 generates light by the lamp driving voltage applied from the outside to the external electrode 211 of the lamp 215.

In addition, the lamps 215 are spaced at a uniform distance and connected in phase in parallel, and are configured in a direct type. Therefore, since light is directly provided on the front surface of the liquid crystal panel 10, the light guide plate (not shown) may be omitted.

The lamp holder 217 is positioned at both ends of the lamp 215 to support and fix the lamp 215. The lamp holder 217 applies a predetermined driving voltage to the external electrode 211 of the lamp 215, and includes a voltage applying means (not shown) for preventing the external electrode 211 from being separated.

Optical sheets 220 are positioned on an upper portion of the lamp unit 210 including the lamp 215 and the lamp holder 217.

The optical sheets 220 serve to diffuse and collect light transmitted from the lamp 215, and may be configured by a plurality of sheets, such as a diffusion sheet and a prism sheet. The diffusion sheet here prevents the light from being partially concentrated by dispersing the light incident from the lamp 215. In addition, the prism sheet has a triangular prism with a regular arrangement on the upper surface, and is generally composed of two sheets, and each prism array is arranged so as to cross at a predetermined angle with each other so that the light diffused from the diffusion sheet is liquid crystal. It serves to condense in a direction perpendicular to the panel 10. Accordingly, the light passing through the prism sheet mostly proceeds vertically, so that the luminance distribution on the protective sheet is uniformly obtained. The protective sheet formed on the prism sheet not only serves to protect the surface of the prism sheet, but also diffuses light in order to uniformize the distribution of light.

In addition, the reflector 230 is positioned under the lamp unit 210.

The reflective plate 230 reflects light leaking to the lower portion of the lamp 215 upwards. The reflective plate 230 may be integrally formed on the bottom surface of the lower receiving container 250.

The upper receiving container 240 and the lower receiving container 250 are fastened to each other to fix and support the respective components of the backlight assembly 200.

In addition, the liquid crystal panel assembly 100 is positioned on an upper surface of the upper storage container 240, and a step (not shown) on which the liquid crystal panel assembly 100 is mounted is formed.

The upper receiving container 240 and the lower receiving container 250 may be coupled through a hook (not shown). For example, a hook is formed along an outer surface of the side wall of the lower receiving container 250, and the hook Hook insertion hole (not shown) corresponding to the may be formed on the side of the upper receiving container (240). Accordingly, as the upper storage container 240 descends from above the lower storage container 250, the hook formed in the lower storage container 250 enters the hook insertion hole formed in the upper storage container 240, thereby lowering the storage container 250. ) And the upper storage container 240 may be fastened. In addition, the combination of the upper receiving container 240 and the lower receiving container 250 may be modified in any known form.

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 printed circuit board and the liquid crystal display including the same, the manufacturing cost can be reduced by reducing the number of components to be mounted.

Claims (8)

Insulating substrate; A circuit pattern for forming a predetermined circuit on the insulating substrate; A first pad group having a plurality of first pads electrically connected to the circuit pattern, the first pad group being opened between the first pads to mount various electronic components; And And a second pad group having a plurality of second pads electrically connected to the circuit pattern, wherein the second pad group is shorted between the second pads. According to claim 1, The second pad is a printed circuit board on which the electronic component is not mounted. According to claim 1, The second pad is shorted by a short wiring pattern, and in the test, the short wiring pattern is cut to open the second pad group. According to claim 1, The printed circuit board of claim 1, further comprising a protective layer formed on a surface of the circuit pattern except for the first pad group and the second pad group. The method of claim 4, wherein The protective layer is a solder resist. The method of claim 4, wherein The protective layer is formed by the screen printing method. According to claim 1, And the first and second pads are plated with nickel / gold. The printed circuit board of claim 1; A liquid crystal panel electrically connected to the printed circuit board and displaying an image; And And a backlight assembly for providing light to the liquid crystal panel.

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