KR20080049540A - Back light structure and liquid crystal display device thereby - Google Patents

Abstract

A backlight structure and an LCD(Liquid Crystal Display) using the same are provided to prevent reduction of an actual image implementation range of the LCD caused when a width of a balance PCB exceeds a bezel portion due to high pressure pattern or component space added on the balance PCB. Balance PCBs(Printed Circuit Boards)(110a,110b) are installed in both sides on a lower cover(100). In the balance PCB, lamp sockets(110a1,110b1) for arranging and fixing lamps(120) are formed. A reflection plate(113) is fastened with an upper side of the balance PCB and the lower cover. In the reflection plate, at least one through hole(113a) corresponding to the lamp socket is formed in both sides. An LC panel(150) is installed in the front of the lamp. The lamp is a cathode cold fluorescent lamp.

Description

BACK LIGHT STRUCTURE AND LIQUID CRYSTAL DISPLAY DEVICE THEREBY}

1 is a cross-sectional view showing the configuration of a liquid crystal display device according to the prior art.

FIG. 2 shows a balance PCB on the lower cover shown in FIG. 1 and an inverter PCB interworking with it

3 is an exploded perspective view showing the configuration of a liquid crystal display according to the present invention.

4 is a perspective view according to another embodiment of the lampholder of FIG.

5 is a perspective view according to another embodiment of the reflecting plate according to the present invention;

Explanation of symbols on the main parts of the drawings

110a, 110b: Balance PCB 110a1, 110b1: Lamp socket

110a2, 110b2: ballast capacitor 113: reflector

The present invention relates to a backlight structure and a liquid crystal display device using the same. More specifically, in a direct type backlight device using a CCFL (Cathode Cold Fluorescent Lamp), a balance PCB in which a plurality of holes are formed on both sides of a string, that is, a reflector plate formed in series, is located on both sides of a lower cover. By connecting through the lampholder on the Balance Printed Circuit Board, it is intended to prevent the reduction of the image implementation range due to the inevitable addition of the area of the Balance PCB.

BACKGROUND ART In general, liquid crystal display devices have tended to be gradually widened due to their light weight, thinness, and low power consumption. According to this trend, LCDs are used for office automation equipment and audio / video equipment. On the other hand, the LCD is controlled to transmit the light beam in accordance with the image signal applied to the control switches arranged in a matrix form to display a desired image on the screen.

However, such an LCD receives light from the backlight device for reasons other than the self-luminous display device. Of course, a cold cathode tube (CFL) is used as a light source for providing the light. CCFL is a light source tube using the cold cathode emission phenomenon, which is an electron emission caused by a strong electric field applied to the cathode surface, it is easy to low heat generation, high brightness, long life, full color (color). The liquid crystal display using the CCFL is to use a direct type backlight device using a plurality of CCFLs in accordance with the trend of larger size.

Here, when the direct backlight device drives a plurality of CCFLs in parallel using one transformer, some of the plurality of CCFLs are driven by the discharge characteristics of the CCFLs. Specifically, the CCFL has an infinite resistance value before being discharged, whereas the CCFL has a small resistance value due to the plasma of the conductor generated inside the glass tube after the discharge. Accordingly, when the CCFL is discharged, the resistance value decreases from the initial stage, thereby increasing the amount of current. Therefore, when a plurality of CCFLs are connected in parallel, the current flows toward the CCFL having a small resistance value after the initial discharge, so that some of the plurality of CCFLs are driven and the others are not driven.

As part of solving the problem, by attaching a capacitor of the same capacity, that is, a ballast capacitor to the positive electrodes of a plurality of CCFLs to form the same equivalent circuit as the External Electrode Fluorescent Lamp (EEFL) A lamp driving device of a liquid crystal display device capable of driving a plurality of CCFLs in parallel using a transformer has been proposed. Here, the EEFL is turned on by applying an alternating current waveform to the external electrode, that is, the discharge occurs in the discharge space inside the glass tube by an electric field caused by a high frequency voltage applied to the pair of external electrodes, and the ultraviolet rays generated by the discharge. The phosphor coated on the inner circumferential surface of the glass tube emits light to generate visible light.

Next, the related contents will be described in more detail with reference to the accompanying drawings. 1 is a cross-sectional view showing the configuration of a direct type liquid crystal display device according to the prior art. As can be seen in the drawing, first, on the lower cover 41, a reflecting plate 42 for reflecting light from the plurality of lamps 48 which are light sources to the front is attached, and the plurality of CCFLs are fastened thereon. Balanced PCBs 49a and 49b) are provided at both sides, and inverter PCBs 50a and 50b for applying an alternating current waveform to the PCBs 49a and 49b are connected to each other. do. The diffuser plate 43 and other optical complementary functions 44 are loaded to uniformly disperse the light reflected from the lamps 48 through the reflector plate 42 to the front surface.

The steps up to now are usually the configuration of the backlight device 40, and then the main support is fastened to maintain the balance of the overall force of the liquid crystal display device, although not separately shown in the drawing. Of course, the main support forms a predetermined pattern in consideration of the liquid crystal panel 20 loaded upward.

The liquid crystal panel 20 mounted on the main support 30 above is a crystal formed by many unit processes. In other words, this is an array substrate 20a in which a thin film transistor as a switching element is arranged for each unit pixel, a color filter substrate 20b having a color filter corresponding thereto, and a liquid crystal injected between two substrates. It is configured to include.

Although not shown separately in the drawing, the upper cover surrounds the outer edge of the liquid crystal panel 20 and the side of the main support, and is fastened to the lower cover 41 through a separate fastening method.

FIG. 2 shows the balance PCBs 49a and 49b on the lower cover 41 as shown in FIG. 1 and the inverter PCBs 50a and 50b linked thereto. Here, the inverter PCBs 50a and 50b change the drive power of the lamp supplied from the outside into an AC waveform, and convert the AC waveform into a high voltage AC waveform again. In addition, a plurality of capacitor patterns 49a1 and 49b1 are formed on the balance PCBs 49a and 49b, so that the amount of current flowing into each tube of each of the plurality of CCFLs 48 is the same and at the same time the inverter PCBs 50a and 50b. By limiting the AC waveform supplied from the ()) serves to limit the current supplied to the plurality of CCFLs (48).

However, in the case of such a balance PCB (49a, 49b), the electrode portion of the lamp may be, for example, 1500Vrms or more, in consideration of this raises the problem of placing the balance component. Therefore, if the safety standard additionally forms high voltage patterns and components, or additionally mounts components such as inductors for more stable lamp driving, the area of the balance PCBs 49a and 49b will inevitably increase. In the module process of the liquid crystal display, the bezel portion, which is the outer edge of the screen, increases, resulting in a reduction in the range of image implementation on the screen.

Therefore, in order to improve the problem, the present invention places the reflector on the upper side of the balance PCB provided on both sides of the lower cover so that the image on the screen is not limited by the bezel size due to the area of the balance PCB provided on the lower cover. It is an object of the present invention to provide a liquid crystal display device which is intended to utilize a wide range of implementations.

And the above and the achievement of the object can be further embodied by the present invention. That is, the liquid crystal display according to the present invention includes a lower cover; A balanced printed circuit board provided on both sides of the lower cover and having lamp sockets arranged and fixed thereto; A reflection plate fastened to an upper side of the balance circuit board and having at least one through hole corresponding to the lamp socket on both sides; Characterized in that it comprises a liquid crystal panel provided to the front of the lamp.

In addition, the backlight structure of the liquid crystal display according to the present invention includes a lower cover; A balance printed circuit board provided on both sides of the lower cover; A lamp socket arranged and fixed on the balance printed circuit board; A reflecting plate fastened on the balance printing substrate and having at least one through hole corresponding to the lamp socket on both sides; It is formed on the lamp socket characterized in that it comprises a fixing means for fixing the reflecting plate.

Then, with reference to the drawings with respect to the above configuration will be described in detail. 3 is an exploded perspective view showing the configuration of a liquid crystal display device according to the present invention. First, as shown in FIG. 3, ballast capacitors 110a2 and 110b2 formed in a pattern to provide a stable current by receiving an alternating current from outside from both sides on the lower cover 100 made of aluminum (Al) or the like, Balance PCBs 110a and 110b are provided with lamp sockets 110a1 and 110b1 for arranging and fixing a plurality of lamps 120 while having conductivity so that the ballast current can stably flow into the lamp 120. Will be fixed.

Then, in order to penetrate the lamp sockets 110a1 and 110b1 positioned at both sides, holes 113a are formed in portions corresponding to the lamp sockets 110a1 and 110b1, respectively. Reflecting plate 113 is attached by penetrating through the plate. Substantially, the reflecting plate 113 is formed at a predetermined distance from the upper side of the balance PCBs 110a and 110b in which the pattern capacitors 110a2 and 110b2 are formed. It is preferable to be fixed over both side grooves 110a1 'of the lampholders 110a1 and 110b1.

Therefore, the distance between the lamp 120 fastened to the lamp sockets 110a1 and 110b1 and the reflector 113 positioned on the rear surface of the lamp 120 may be maintained within a range of about 5 mm. In other words, when the distance between the lamp 120 and the reflector 113 exceeds 5 mm, it may affect the optical sheet (not shown) fastened to the upper side and cause wrinkles due to heat, while the lamp 120 Is in close contact with the reflector plate 113, it may affect the high-voltage pattern on the balance PCB (110a, 110b) located below. Therefore, the above range is only a consideration for the optimal design of the present invention and will not necessarily be limited thereto.

In addition, the material of the reflector plate 113 is a film coated with a white polyester film or metal (Ag, Al), etc., the light reflectance of the visible light in the reflector plate 113 is about 90 ~ 97% and the coated film The thicker this is, the higher the reflectance is.

In addition, the lamp sockets 110a1 and 110b1 positioned at both sides of the lamp socket 110 are fastened so that a plurality of lamps 120 are arranged in series. In the case of a large-area LCD TV, about 16 inches on a 32-inch basis for high brightness It is known to arrange two lamps at regular intervals, and about 20 lamps in the case of 40 inches. Subsequently, in order to protect the balance PCBs 110a and 110b including the lampholders 110a1 and 110b1 positioned at both sides, a predetermined fixing member, that is, the side support 130 is loaded.

In addition, a diffuser plate (not shown) and light emitted through the diffuser plate (not shown) for uniformly dispersing the light emitted directly from the lamps 120 and the light reflected through the reflector plate 113 to the front surface of the lamp 120 Optical sheets (not shown) are loaded to have additional properties.

As such, when the loading process to the optical sheet (not shown), that is, the fastening process of the backlight device is finished, the main support 140 is fastened to maintain the balance of the overall force in the liquid crystal display device. Of course, the main support 140 here forms a pattern in consideration of the liquid crystal panel 150 loaded on the front surface.

On the other hand, the liquid crystal panel 150 mounted on the main support 140 is a crystal composed of many unit processes. In other words, the switching element comprises an array substrate in which thin film transistors are arranged for each unit pixel, a color filter substrate on which a color filter representing color is formed, and a liquid crystal injected between the two substrates. .

In addition, the upper cover 160 is fastened to the lower cover 100 while surrounding the four surface edges of the liquid crystal panel 110 and the side surfaces of the main support 140.

However, in such a configuration, when the ballast capacitors 110a2 and 110b2 as shown in FIG. 3 are additionally configured with a high pressure pattern interlocking with each other, the ballast capacitors 110a2 and 110b2 and the high pressure pattern are respectively facing lamps. If the configuration on the balance PCB (110a, 110b) in the inward direction of the socket (110a1, 110b1) can be additional circuit design without regard to the area of the balance PCB (110a, 110b) on the lower cover 140 eventually. There will be.

In addition, in order to fasten the reflecting plate 113 shown in FIG. 3, both grooves 110a1 'of the lamp sockets 110a1 and 110b1 may be formed in any position, and furthermore, the grooves 110a1' are shown in FIG. It may be formed as long as the protrusion 210a as shown. Of course, the forming portion of the projection 210a may be formed of any portion of the lamp socket 210, but it should be clear that at least one should be formed. Through this, it is possible to fix the reflector plates 113 fastened on the upper sides of the balance PCBs 110a and 110b.

In addition, the reflecting plate according to the present invention may be changed as many as the lamp sockets penetrating the reflecting plate are arranged.

For example, FIG. 5 illustrates a shape of a reflecting plate 313 in which a plurality of through holes 313a are formed in series, which is a plurality of lamp sockets 110a1 arranged in series as shown in FIG. In the case where a plurality of 110b1s are arranged in series, the fastening can be facilitated by forming holes 313a in the reflecting plate 313 so as to correspond to each other.

As a result, the liquid crystal display according to the present invention realizes the actual image of the liquid crystal display device caused by the width of the balance PCB exceeding the bezel area due to the high-voltage pattern or the space of the parts added on the balance PCB in accordance with safety standards. This could prevent a reduction in scope.

Claims (10)

Lower cover; A balance printed circuit board provided on both sides of the lower cover and having a lamp socket for arranging and fixing the lamps; A reflection plate fastened to the balance printed circuit board and the lower cover and having at least one through hole corresponding to the lamp socket on both sides; And a liquid crystal panel provided in front of the lamp. The liquid crystal display of claim 1, wherein the lamp is a cathode cold fluorescent lamp. The liquid crystal display device according to claim 1, wherein the lamp socket is provided with a groove for fastening the reflective plate. The liquid crystal display device according to claim 1, wherein the lamp socket is provided with a projection for fastening the reflective plate. The liquid crystal display device according to claim 1, wherein a distance X between the lamp and the reflector is in a range of 0 < Lower cover; A balance printed circuit board provided at both sides of the lower cover; A lamp socket arranged and fixed on the balance printed circuit board; A reflective plate fastened on the balance printed circuit board and the lower cover and having at least one through hole corresponding to the lamp socket on both sides; And a fixing means formed on the lamp socket to fix the reflecting plate. 7. The backlight structure of a liquid crystal display device according to claim 6, wherein the lamp is a cold cathode fluorescent lamp. 7. The backlight structure of claim 6, wherein the fixing means is a groove. 7. The backlight structure of a liquid crystal display device according to claim 6, wherein the fixing means is a projection. 7. The backlight structure of a liquid crystal display device according to claim 6, wherein the distance X between the lamp and the reflector is in the range of 0 <

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