KR20080037182A - Liquid crystal display device - Google Patents

Abstract

An LCD(Liquid Crystal Display) device is provided to separate a balance PCB for adjusting a lamp tube current from an inverter PCB and arrange the balance PCB in the inside of a lower cover, thereby reducing the production cost of a PCB and making the PCB small. An LCD device comprises an LCD panel, a plurality of lamps(190), a lower cover(150), at least one balance PCB(Printed Circuit Board)(120a,120b), and an inverter PCB. The plurality of lamps supply light sources to the LCD panel. The plurality of lamps are arrange at regular intervals on the lower cover. The at least one balance PCB has a power connector(170a,170b) for supplying power to the plural lamps in the inside of the lower cover. The inverter PCB is arranged in the rear of the lower cover to supply power to the balance PCB.

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY DEVICE}

1 is a view in which the inverter PCB is fastened to the bottom cover bottom of the liquid crystal display according to the prior art.

FIG. 2 is an enlarged view of a region A of FIG. 1. FIG.

3 is a bottom view of a lower cover of the liquid crystal display device in which the balance PCB of the inverter is separated according to the present invention;

4 is a view showing a state in which the balance PCB of the inverter is mounted on the inner side of the lower cover of the liquid crystal display according to the present invention.

5 is a view showing the structure of a balance PCB of the liquid crystal display according to the present invention.

FIG. 6 is an enlarged view of region B of FIG. 5.

7A and 7B illustrate a state in which a lamp is fastened to a lamp connector integrally formed on a balance PCB of the liquid crystal display according to the present invention.

8 is a view showing a state in which the master PCB, the slave PCB and the balance PCB is connected in the liquid crystal display according to the present invention.

* Description of the symbols for the main parts of the drawings *

110: cable 120a: first balance PCB

120b: second balance PCB 130: master inverter PCB

140: slave inverter PCB 150: lower cover

142a: first balance part 142b: second balance part

170a: first power connector 170b: second power connector

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device which can reduce manufacturing size while reducing the size of an inverter by arranging a balanced printed circuit board (PCB) inside the lower cover to control tube current deviation of a lamp. .

CRT (Cathode Ray Tube), one of the commonly used display devices, is mainly used for monitors such as TVs, measuring devices, and information terminal devices.However, due to the weight and size of the CRT itself, Could not respond actively to demands.

Therefore, in the trend of miniaturization and weight reduction of various electronic products, CRT has a certain limit in weight and size, and is expected to replace the liquid crystal display (LCD) and gas discharge using electro-optic effects. Plasma Display Panel (PDP) and Electro Luminescence Display (ELD) using the electroluminescent effect, and the like, among them, researches on liquid crystal displays are being actively conducted.

In order to replace the CRT, a liquid crystal display device having advantages such as small size, light weight, and low power consumption has been actively developed, and recently, the monitor of a laptop computer has been developed enough to perform a role as a flat panel display device. In addition, the demand for liquid crystal display devices continues to increase as they are used in monitors and large information display devices of desktop computers.

Since most of the liquid crystal display devices are light-receiving devices that display an image by controlling the amount of light coming from the outside, a separate light source for irradiating light to the LCD panel, that is, a backlight unit is required. .

The backlight unit used as the light source of the liquid crystal display device is a method of arranging a cylindrical light emitting lamp, and is divided into an edge method and a direct method.

In the double-edge method, the lamp unit is installed on the side of the light guide plate for guiding the light, and the lamp unit covers a lamp emitting light, a lamp holder inserted at both ends of the lamp to protect the lamp, and an outer circumferential surface of the lamp, and one side It is provided with a lamp reflector plate fitted to the side of the light guide plate to reflect the light emitted from the lamp toward the light guide plate.

As such, the edge method in which the lamp unit is installed on the side of the light guide plate is mainly applied to a liquid crystal display device having a relatively small size, such as a monitor of a laptop computer and a desktop computer, and has good light uniformity and a long durability life. It is advantageous to thin the liquid crystal display device.

On the other hand, the direct type method has been developed mainly as the size of the liquid crystal display device has increased to 20 inches or more. will be.

The direct method is mainly used for a large screen liquid crystal display device requiring high luminance because the light utilization efficiency is higher than that of the edge method.

1 is a view in which the inverter PCB is fastened to the bottom cover bottom of the liquid crystal display according to the prior art.

As shown in FIG. 1, a master inverter PCB 30 for supplying power to the lamps on a rear surface of the lower cover 50 in which a liquid crystal display panel, an optical sheet, and a plurality of lamps (not shown) are disposed on a front surface thereof. And a slave inverter PCB 40 are arranged.

As described above, the master inverter PCB 30 and the slave inverter PCB 40 respectively supply high-voltage voltages having different phases to the lamps. EEFL (External Electrode Fluorescent Lamp) and CCFL (Cold Cathode Fluorescent Lamp).

Both electrodes of the lamps are connected in parallel to a power terminal for receiving a voltage from the master inverter PCB 30 and a power terminal for receiving a voltage from the slave inverter PCB 40 at predetermined intervals.

The gating synchronization signal from the main controller is received between the master inverter PCB 30 and the slave inverter PCB 40 to synchronize the voltage generated by the master inverter PCB 30 with the voltage generated by the slave inverter PCB 40. Therefore, a cable 45 for synchronizing voltages is connected between the master inverter PCB 30 and the slave inverter PCB 40.

In addition, the balance PCB 20 for mounting a constant tube current flowing through the lamp is mounted together on the master inverter PCB 30 or the slave inverter PCB 40.

FIG. 2 is an enlarged view of the region A of FIG. 1, and as shown, a balance PCB 20 formed on the master inverter PCB 30 in an area outside the lower cover 50 where the master inverter PCB 30 is located. And lamp terminals (not shown) inside the lower cover 50 are electrically connected by the cable 44 and the connector 41.

Connectors 41 are arranged at predetermined intervals on the balance PCB 20 formed on the master inverter PCB 30, and each of the connectors 41 is disposed inside the lower cover 50 through the cable 44. Electrical connection with the connected lamp connector (not shown).

Although not shown in the figure, 42, which is not described, is a balance section 42 for adjusting lamp tube current. The balance part 42 is a transformer or a capacitor formed of a coil.

The conventional liquid crystal display device having the above structure has the following problems.

First, the main controller and the inverter protection circuit is further mounted on the master inverter PCB 30, there is a problem that the size of the inverter PCB is very large when forming the balance PCB 20 for controlling the lamp tube current together. .

As such, when the inverter PCB is enlarged, the manufacturing cost increases, and there is a limit in miniaturizing the liquid crystal display.

Second, the balance part 42 formed on the balance PCB 20 is composed of a thin coil or a capacitor, which is easily broken by an external shock.

Third, when too many components are mounted on the inverter PCB, a lot of heat is generated, thereby reducing the reliability of the mounted device. In addition, PCB warpage may occur frequently due to the increase in size of the inverter PCB.

The present invention is to provide a liquid crystal display device that can realize a miniaturization while reducing the PCB manufacturing cost by separating the balance PCB for controlling the lamp tube current from the inverter PCB, and by placing the separated balance PCB inside the lower cover. have.

In order to achieve the above object, the liquid crystal display device according to the present invention,

A liquid crystal display panel;

A plurality of lamps supplying a light source to the liquid crystal display panel;

A lower cover in which the plurality of lamps are arranged at predetermined intervals;

At least one balance PCB provided with a power connector to supply power to the plurality of lamps inside the lower cover; And

And an inverter PCB disposed on a rear surface of the lower cover to supply power to the balance PCB.

According to the present invention, the balance PCB for controlling the lamp tube current is separated from the inverter PCB, and the separated balance PCB is disposed inside the lower cover, thereby reducing the PCB manufacturing cost and miniaturization.

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

3 is a diagram illustrating a bottom cover of a liquid crystal display device in which a balance PCB of an inverter is separated according to the present invention, and FIG. 4 is a view illustrating a balance PCB of the inverter mounted on an inner side of a lower cover of an LCD device according to the present invention. It is a figure which shows a state.

3 and 4, a master inverter PCB 130 and a slave inverter PCB 140 are disposed on the bottom of the lower cover 150, respectively, and two PCBs are disposed. It is connected by a cable 110 to synchronize the supply voltage. The master inverter PCB 130 may further include a transformer and a controller for applying current to the lamps 190 disposed inside the lower cover 150.

In addition, a balance PCB may be disposed in the region of the master inverter PCB 130 or the slave inverter PCB 140 to adjust the tube current flowing through each of the lamps 190. In the present invention, a case where the first balance PCB 120a and the second balance PCB 120b are disposed in the master inverter PCB 130 and the slave inverter PCB 140 will be described. However, the same applies to the case where the balance PCB is disposed only in one of the region of the master inverter PCB 130 or the slave inverter PCB 140.

When the first balance PCB 120a and the second balance PCB 120b are disposed on both sides of the lamps 190 as in the present invention, the first and second balance PCBs 120a and 120b are respectively master master inverters. Separately manufactured from the PCB 130 and the slave inverter PCB 140, and then disposed on the inner surface of the lower cover 150, each lamp 190 is disposed.

Lamps used in the present invention are EEFL (External Electrode Fluorescent Lamp) having an external electrode or CCFL (Cold Cathode Fluorescent Lamp) having an internal electrode.

Therefore, as shown in FIG. 4, the first balance PCB 120a and the second balance PCB 120b are disposed at both sides of the lamps 190. Also, in the present invention, first and second power connectors 170a and 170b are formed on the first and second balance PCBs 120a and 120b to be coupled to both electrodes of the lamps 190. . That is, in the present invention, the first and second power connectors 170a and 170b for supplying power to the lamps 190 are integrally formed on the first and second balance PCBs 120a and 120b.

In addition, the first balance parts 142a for adjusting the lamp 190 tube current are arranged at predetermined intervals on the first balance PCB 120a, and the lamp 190 tube current is adjusted on the second balance PCB 120b. The second balance parts 142b are arranged at predetermined intervals.

The first and second balance units 142a and 142b may be formed of a transformer or a capacitor each configured of a coil.

That is, in the present invention, the master inverter PCB 130 and the slave inverter PCB 140 are disposed on the bottom cover 150 of the liquid crystal display, respectively, and the first and second balance PCBs for controlling the tube current of the lamps 190. 120a and 120b are disposed inside the lower cover 150. Therefore, the size of the master inverter PCB 130 and the slave inverter PCB 140 can be manufactured much smaller than before.

Although not illustrated in the drawings, when the balance PCBs 120a and 120b are separated and manufactured as in the present invention, the master inverter PCB 130 and the slave inverter PCB 140 may be integrally formed on one PCB. In this case, only one inverter PCB is disposed on one side of the lower cover 150 so that the structure of the inverter can be greatly simplified, and a cable for synchronizing the master inverter PCB 130 and the slave inverter PCB 140 is not formed. There is no need to save parts.

5 is a diagram illustrating a structure of a balance PCB of the liquid crystal display according to the present invention, and FIG. 6 is an enlarged view of region B of FIG. 5.

5 and 6, a plurality of first balance parts 142a are arranged on the first balance PCB 120a at regular intervals, and each of the first balance parts 142a is provided with an electrode of a lamp. And a first power connector 170a which is directly fastened to each other. In the drawing, two first power connectors 170a are disposed on both sides of the first balance unit 142a, but the number of power connectors varies depending on the number of lamps and the configuration of the balance unit. Can be changed.

In addition, the first balance part 142a is formed of a coil wound transformer, but it is not fixed but may be variously applied as long as it is an element capable of controlling lamp tube current. For example, the capacitor may be disposed to correspond 1: 1 with the lamp to adjust the lamp tube current.

The first power connector 170a has a groove formed to fasten and fix an electrode formed at one edge of the lamp. Each of the first power connectors 170a is electrically connected to the first balance part 142a, so that the current supplied to the first balance PCB 120a is primarily controlled by the first balance part 142a. Next, each lamp is applied to each lamp through the first power connector 170a.

Therefore, the uniform current adjusted by the first balance unit 142a is applied to each of the lamps.

7A and 7B illustrate a state in which a lamp is fastened to a lamp connector integrally formed on a balance PCB of the liquid crystal display according to the present invention.

7A and 7B, lamps 190 are fastened on the first balance PCB 120a under the liquid crystal display panel 250.

The master inverter PCB 130 is disposed on the bottom of the lower cover 150, and a first balance PCB having the first power connector 170a and the first balance part 142a mounted therein. 120a) is arranged.

Therefore, the lamps 190 are fastened to and disposed on a plurality of first power connectors 170a formed at a predetermined interval on the first balance PCB 120a. Although not clearly shown in the drawings, the master inverter PCB 130 supplies power to the first power connector 170a of the first balance PCB 120a via a cable.

In addition, although not shown in the drawings, the second balanced PCB region has the same fastening structure as that of the first balanced PCB 120a region.

A diffusion plate 210 is disposed on the lamps 190 to diffuse light, and a liquid crystal display panel 250 is disposed on the diffusion plate 210. The liquid crystal display panel 250 has a structure in which a lower substrate having a switching element and an upper substrate having R, G, and B color filter layers are bonded to each other with a liquid crystal layer interposed therebetween.

8 is a view illustrating a state in which a master PCB, a slave PCB, and a balance PCB are connected in the liquid crystal display according to the present invention.

As shown in FIG. 8, the master inverter PCB 130 and the slave inverter PCB 140 are disposed on the rear surface of the liquid crystal display lower cover 150, and between the master inverter PCB 130 and the slave inverter PCB 140. The cable 110 for synchronizing the voltage to be supplied is connected.

In addition, the master inverter PCB 130 is formed with a power cable 220a and a power outlet 220b to apply power to a power connector (not shown) formed on the first balance PCB disposed inside the lower cover 150. It is. Similarly, the slave inverter PCB 140 is formed with a power cable 220a and a power outlet 220b to apply power to a power connector (not shown) formed on a second balance PCB disposed inside the lower cover 150. It is.

Therefore, the voltage generated by the master inverter PCB 130 and the slave inverter PCB 140 is transferred to the power cable 220a and the power outlet 220b, and the transferred voltage is a balance PCB disposed inside the lower cover 150. Is supplied. The balance PCB adjusts the lamp tube current deviation in a balance part composed of a transformer or a capacitor, and then supplies it to a power connector so that the lamp is finally powered.

As described in detail above, the present invention has the effect of reducing the PCB manufacturing cost and miniaturization by separating the balance PCB for controlling the lamp tube current from the inverter PCB, and by placing the separated balance PCB inside the lower cover have.

The present invention is not limited to the above-described embodiments, and various changes can be made by those skilled in the art without departing from the gist of the present invention as claimed in the following claims.

Claims (9)

A liquid crystal display panel; A plurality of lamps supplying a light source to the liquid crystal display panel; A lower cover in which the plurality of lamps are arranged at predetermined intervals; At least one balance PCB provided with a power connector to supply power to the plurality of lamps inside the lower cover; And And an inverter PCB disposed on a rear surface of the lower cover to supply power to the balance PCB. The liquid crystal display of claim 1, wherein the balance PCB further comprises a balance unit for adjusting tube current of each of the plurality of lamps. The liquid crystal display device according to claim 2, wherein the balance part is a transformer or a capacitor. The liquid crystal display of claim 1, wherein the balance PCB is disposed on both sides of the plurality of lamps. The liquid crystal display of claim 1, wherein the power connector formed on the balance PCB is formed to correspond to each of a plurality of lamps. The liquid crystal display of claim 1, wherein the inverter PCB is electrically connected to the balance PCB, a power cable, and a power outlet. 7. The liquid crystal display of claim 6, wherein the inverter PCB penetrates the lower cover inward from the rear surface and is electrically connected by a power cable and a power outlet. The liquid crystal display of claim 1, wherein the inverter PCB is an inverter PCB in which a master inverter PCB and a slave inverter PCB are integrally formed. The liquid crystal display device of claim 1, further comprising a diffusion plate disposed between the liquid crystal display panel and the plurality of lamps.

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