KR20000040700A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: A liquid crystal display device is provided to reduce the thickness of the liquid crystal display device and to increase light equalization. CONSTITUTION: A liquid crystal display device includes a mold frame(110), a reflection sheet(120), a light conduction plate(122), lamp assemblies(130,140) and optical sheets(124). The lamp assemblies include cold cathode ray lamps(132,142), lamp holders(133,144), a lamp reflection plate, and an inverter. The mold frame(110) includes a container slit(112). The reflection sheet(120) is implemented at the bottom of the container slit. The light conduction plate(122) is formed on the reflection sheet and controls the amount of light. The at least two lamp assemblies(130,140) are implemented on the side of the light conduction plate and emits light. The optical sheets(124) are formed on the light conduction plate and diffuses and concentrates the light guided by the light conduction plate.

Description

LCD Display

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device in which at least two or more lamp assemblies are provided on a side of at least one light guide plate in a large liquid crystal display device to improve reliability of the large liquid crystal display device. .

CRT (Cathode Ray Tube), one of the widely used display devices, is mainly used for monitors such as TVs, measuring devices, information terminal devices, etc., but due to the weight and size of the CRT itself, the miniaturization and weight reduction of electronic products Could not respond actively to the demands of.

In order to replace the CRT, a liquid crystal display device having advantages of small size, light weight, and low power consumption has been actively developed, and recently, it has been developed enough to perform a role as a flat panel display device. In addition, as the monitor and the large information display device of the desktop computer is used, the demand for the liquid crystal display device is continuously increasing.

Since the liquid crystal display is a light receiving device that displays an image by controlling the amount of light coming from the outside, a separate light source, that is, a backlight assembly, for irradiating light to the LCD panel is necessary.

The backlight assembly of a liquid crystal display device used in a laptop computer and a desktop computer includes a mold frame having a large storage space, a reflective plate installed on the base surface of the storage space to reflect light, and a light guide installed on the reflective plate to guide the light. It consists of a light guide plate, an optical sheet installed on the upper part of the light guide plate for diffusing and condensing guided light, and a lamp assembly installed on one side or both sides of a long side of the light guide plate to emit light.

Here, the lamp assembly includes a cold cathode tube lamp for emitting light, a lamp holder inserted at both ends of the cold cathode tube lamp to protect the cold cathode tube lamp, and an outer circumferential surface of the cold cathode tube lamp to reflect light emitted from the cold cathode tube lamp toward the light guide plate. It is composed of a lamp cover, which is the way the lamp assembly is installed on the side of the light guide plate is called an edge type.

On the other hand, the backlight assembly of the large-screen liquid crystal display used in the large information display device is also composed of a mold frame, a reflector, a light guide plate, optical sheets and a lamp assembly as described above, except that a hot cathode tube lamp is used. The configuration also has the same configuration as described above and the lamp assembly is installed in an edge type.

On the other hand, when the lamp is used as a cold cathode tube, the configuration of the backlight assembly of the large-screen liquid crystal display is different. The backlight assembly includes a mold frame in which a storage space is formed, a lamp assembly installed at a base surface of the storage space, and an upper portion of the lamp assembly. And a diffuser plate for diffusing the light emitted from the lamp assembly, and an optical sheet provided on the diffuser plate to collect the diffused light.

Here, the lamp assembly is composed of a lamp holder formed with a plurality of semi-circular grooves in the width direction of the diffuser plate, and cold cathode tube lamps which are mounted on the semi-circular grooves to emit light. The way of installation is called direct type.

The reason why it is not possible to install the lamp assembly in which the cold cathode tube lamp is used in the large liquid crystal display on the side of the light guide plate is due to the problem of gas encapsulation and the warpage of the lamp. This is because the cathode ray tube lamp cannot be made.

However, when the lamp assembly is installed in an edge type in the large-screen liquid crystal display, the heat emitted from the hot cathode tube lamp degrades the performance of the liquid crystal material, consumes a lot of power, and shortens the life of the hot cathode tube lamp, thereby increasing the reliability of the LCD module. There is a problem of this deterioration.

On the other hand, when the lamp assembly is installed directly in the large-screen liquid crystal display device, the thickness of the liquid crystal display device is increased due to the thickness of the lamp holder and the space between the cold cathode tube lamp and the diffusion plate.

In addition, since the cold cathode tube lamp is installed in the lower portion of the diffusion plate, the portion corresponding to the cold cathode tube lamp in the LCD panel is bright and the portion where the cold cathode tube lamp is not installed is relatively dark, so that the uniformity of light is reduced.

Accordingly, an object of the present invention has been devised in view of the above problems, to reduce the thickness of the large-screen liquid crystal display device and to improve light uniformity.

Another object of the present invention is to prolong the life of the lamp used as a light source of the lamp assembly, to suppress heat dissipation, and to reduce power consumption.

Still other objects of the present invention will become more apparent from the following detailed description and the accompanying drawings.

1 is an exploded perspective view showing a large screen liquid crystal display device according to the present invention;

2 is a perspective view illustrating a state in which two lamp assemblies are installed in a mold frame;

3 is a perspective view showing a lamp and a lamp holder according to the present invention.

4 is a view schematically showing a state in which the lamp assemblies according to the first embodiment of the present invention are installed on both side surfaces of the light guide plate,

5 is a view schematically showing a state in which the lamp assemblies according to the second embodiment of the present invention are installed on both side surfaces of the light guide plate.

6 is a plan view showing a diffuse reflection portion of the light guide plate according to the present invention;

7 and 8 are cross-sectional views schematically showing the structure of a lamp assembly according to a third embodiment of the present invention.

In order to achieve the above object, the present invention is provided with two or more lamp assemblies in series on at least one side of the light guide plate, the length of the lamp assemblies is shorter than the side length of the light guide plate on which the lamp assemblies are to be installed.

For example, the lamp assemblies may be installed on two opposite sides of the light guide plate, and the lamp assembly may be disposed at first ends of opposite sides of the light guide plate, and at opposite ends of the light guide plate. It consists of a second lamp assembly which is installed spaced apart from the first lamp assembly a predetermined interval.

Preferably, the length of the first lamp assembly and the length of the second lamp assembly are formed equal to each other.

Preferably, the length of the first lamp assembly and the length of the second lamp assembly are formed differently, and the second lamp assemblies are installed on each side of the light guide plate so as to face the first lamp assemblies installed on each side of the light guide plate opposite to each other. do.

Hereinafter, the liquid crystal display according to the present invention will be described with reference to FIGS. 1 to 8.

The basic concept of the present invention is to provide at least one lamp assembly shorter than the side length of the light guide plate to at least one side of the light guide plate in order to equalize the length of the lamp assembly using the cold cathode tube lamp as the light source and the side length of the light guide plate. will be.

As shown in FIG. 1, the large screen liquid crystal display device 100 is formed on a mold frame 110 having a predetermined size of a receiving groove 112 along an edge thereof, and installed on a base surface of the receiving groove 112. Reflecting sheet 120 and reflecting the light guide plate 122 is installed on the upper surface of the reflective sheet 120 to guide the light in the upper direction, and installed on the upper surface of the light guide plate 122 to diffuse the guided light Optical sheets 124 for condensing, two or more lamp assemblies 130 and 140 installed in series on the side of the at least one light guide plate 122 to emit light, and on the lower surface of the mold frame 110. The bottom chassis 150 is installed to support each member stacked in the receiving groove 112, and an LCD panel (not shown) installed on the optical sheets 124 to display information.

Here, in the large-screen liquid crystal display 100 shown in FIG. 1, two lamp assemblies 130 and 140 are installed on both side surfaces of the light guide plate 122 in the width direction, which is illustrated in the large-screen liquid crystal display 100. This is to increase the luminance and prevent the dark portion from occurring in many parts. Hereinafter, only a case in which two lamp assemblies, that is, the first lamp assembly 130 and the second lamp assembly 140 are installed on each of both side surfaces of the light guide plate 122 will be described.

As shown in FIG. 1 or 2, the first and second lamp assemblies 130 and 140 have hot electrodes 131 and 141 formed at one end thereof and cold electrodes 133 and 143 formed at the other end thereof. The cold cathode tube lamps 132 and 142 which are formed to emit light, the lamp holders 134 and 144 which are fitted at both ends of the cold cathode tube lamps 132 and 142 to protect the cold cathode tube lamps 132 and 142, and cold Lamp reflectors 136 and 146 which surround the cathode tube lamps 132 and 142 and face the light guide plate 122 and are fitted to the light guide plate 122, and hot and cold electrodes of the cold cathode tube lamps 132 and 142. And wires 138 and 148 connected to 131 and 141 and 133 and 143 to apply a high voltage to the cold cathode lamps 132 and 142.

Here, the cold cathode tube lamps 132 and 142 having lengths corresponding to the long side lengths of the light guide plate 122 may not be manufactured due to gas encapsulation problems and warpage of the cold cathode tube lamps 132 and 142. Alternatively, as shown in FIG. 5, the first lamp assembly 130 and the second lamp assembly 140 are formed in one pair and installed on one side and the other side in the width direction of the light guide plate 122.

That is, the first lamp assembly 130 and the second lamp assembly 140 are installed to be spaced apart from each other by a predetermined distance on one side of the light guide plate, and the first lamp assembly 130 and the second lamp assembly on the other side of the light guide plate. Since the 140 140 are spaced apart from each other by a predetermined interval, four lamp assemblies are installed in one light guide plate 122.

Accordingly, when the lamp assembly is separated into the first and second lamp assemblies 130 and 140, the lamp assembly using the cold cathode tube lamp may also be installed on the long side of the light guide plate 122 to reduce the size of the large liquid crystal display. have.

According to the first exemplary embodiment of the present invention, the first lamp assembly 130 and the second lamp assembly 140 are manufactured to have the same length, and as shown in FIG. 4, the central portions of both side surfaces of the light guide plate 122 in the width direction are formed. As a reference, the first lamp assemblies 130 may be installed on the left side of the light guide plate 122, and the second lamp assemblies 140 may be spaced apart from the first lamp assemblies 130 by a predetermined distance. It is installed on the right side respectively.

As such, when the first lamp assembly 130 and the second lamp assembly 140 have the same length, the respective members constituting the first and second lamp assemblies 130 and 140 may be used in common. There is this.

Meanwhile, according to the second embodiment of the present invention, the length of the first lamp assembly 130 and the length of the second lamp assembly 140 are different from each other. Preferably, the length of the first lamp assembly 130 is 1/2 of the length of the second lamp assembly 140.

The arrangement of the first lamp assembly 130 and the second lamp assembly 140 having different lengths on one side of the long side of the light guide plate 122 is based on the center of the light guide plate 122 as shown in FIGS. 1 and 5. The short first lamp assembly 130 is installed on the left side of the light guide plate 122, and the long second lamp assembly 140 is spaced apart from the first lamp assembly 130 by a predetermined distance from the light guide plate 122. The light guide plate 122 is installed on the right side of the center.

In addition, the arrangement of the first lamp assembly 130 and the second lamp assembly 140 on the other long side of the light guide plate 122 may include the first and second lamp assemblies 130 installed on one side of the long side of the light guide plate 122. 140 is installed to face each other, in order to prevent the separation space 135 between the first lamp assembly 130 and the second assembly 140 from appearing darker than other portions.

That is, on the other side of the long side of the light guide plate 122, the second lamp assembly 140 having a long length relative to the center of the light guide plate 122 is installed on the left side of the light guide plate 122, and the short first lamp assembly ( The 130 is spaced apart from the second lamp assembly 140 by a predetermined distance and is installed on the right side of the light guide plate 122 with respect to the center of the light guide plate 122.

As such, the second lamp assembly 140 and the second lamp assembly 140 may be disposed on the other side of the light guide plate 122 so as to face each other with the first and second lamp assemblies 130 and 140 arranged on one side of the light guide plate 122 in the width direction. When the first lamp assembly 130 is arranged, light emitted from each of the second lamp assemblies 140 may also be transmitted to the separation space 135 between the first lamp assembly 130 and the second lamp assembly 140. It is possible to minimize the phenomenon that the interface between the first lamp assembly 130 and the second lamp assembly 140 is darker than other portions.

In addition, the present invention provides a lamp holder 134 of the first and second lamp assembly (130, 140) in order to minimize the generation of the dark portion at the boundary between the first lamp assembly 130 and the second lamp assembly (140). The lower ends of the lamp holders 134 and 144 installed on the inner side of the light guide plate 122, that is, the side facing the first lamp assembly 130 or the second lamp assembly 140, as shown in FIG. 3. Handle or pick corners.

As such, when the lower ends of the lamp holders 134 and 144 are processed to have a round shape, for example, light emitted from the cold cathode tube lamps 132 and 142 is discharged from the lamp holder 134 as illustrated in FIG. 3 or 4. Since the light is transmitted to the separation space 135 between the first lamp assembly 130 and the second lamp assembly 140 along the round, the dark portion generated in the separation space 135 may be improved.

Alternatively, as shown in FIG. 6, the first reflecting parts 123 for controlling the amount of light incident from the first and second lamp assemblies 130 and 140 are formed on the lower surface of the light guide plate 122. The diffuse reflection part 123 is densely formed in a portion corresponding to the separation space 135 between the lamp assembly 130 and the second lamp assembly 140 to improve the dark part.

Here, the diffuse reflection parts 123 are formed to be the smallest in the vicinity of the first and second lamp assemblies 130 and 140, and gradually increase in the distance from the first and second lamp assemblies 130 and 140. do. That is, the size of the diffuse reflection parts 123 formed in the central portion of the light guide plate 122 is the largest.

Alternatively, as illustrated in FIG. 4, the hot electrodes 131 and 141 to which the high voltage is applied among the cold cathode tube lamps 132 and 142 of the first and second lamp assemblies 130 and 140 may be disposed inside the light guide plate 122. That is, the first lamp assembly 130 or the second lamp assembly 140 is positioned on the side facing the cold light guide plate 122, the cold electrodes 133, 143 are positioned.

Here, since the hot electrodes 131 and 141 of the cold cathode tube lamps 132 and 142 have higher luminance than the cold electrodes 133 and 143, the space between the first lamp assembly 130 and the second lamp assembly 140 is increased. It can be minimized that the space 135 looks darker than the other portions.

However, when the hot electrodes 131 and 141 of the cold cathode tube lamps 132 and 142 are positioned inside the light guide plate 122 and the cold electrodes 133 and 143 are positioned outside the light guide plate 122, the inverter 160 may be used. Since the light guide plate 122 is installed at the center portion of the light guide plate 122, the components are not mounted in a portion in which the inverter 160 is installed in a driving device (not shown) for driving the liquid crystal display device 100, thereby constraining space.

Accordingly, as shown in FIG. 5, the hot electrodes 131 and 141 of the cold cathode tube lamps 132 and 142 are positioned outside the light guide plate 122, and the cold electrodes 133 and the cold electrodes of the cold cathode tube lamps 132 and 142 are positioned. The inverter 160 may be positioned outside the light guide plate 122 by placing the 143 inside the light guide plate 122.

According to the third embodiment of the present invention, two or more cold cathode tube lamps are provided in each of the first and second lamp assemblies 130 and 140 in order to increase the luminance of the large liquid crystal display device 100.

Taking the first lamp assembly 130 as an example, it will be described in more detail. As shown in FIG. 6, the first cold cathode tube lamp 132a may be parallel to the first cold cathode tube lamp 132a adjacent to the light guide plate 122. The second cold cathode lamp 132b is installed at the rear end.

Alternatively, as shown in FIG. 7, a second cold cathode tube lamp 132b is installed below the first cold cathode tube lamp 132a to be perpendicular to the first cold cathode tube lamp 132a adjacent to the optical sheets 124. do.

Meanwhile, as illustrated in FIG. 1, a short prevention plate 115 is provided on both side walls in the width direction in which the first and second lamp assemblies 130 and 140 are installed among the accommodation grooves 112 of the mold frame 110. Protruding to a length to isolate between the first lamp assembly 130 and the second lamp assembly 140 as shown in FIG.

This is because when the first and second lamp assemblies 130 and 140 are flowed by an impact or vibration applied from the outside of the liquid crystal display device 100, the in / cold electrodes 131 and 133 of the first lamp assembly 130 are moved. ) And the inlet / cold electrodes 141 and 143 of the second lamp assembly 140 are prevented from shorting.

As described above, the present invention provides a lamp assembly using a cold cathode tube lamp as a light source in at least one side of the light guide plate in a large-screen liquid crystal display, and has a lamp assembly shorter in length than the side length of the light guide plate on which the lamp assembly is to be installed. Install at least two to match the length of the side of the light guide plate and the length of the lamp assembly.

As such, when two or more lamp assemblies are installed in series on at least one light guide plate, the thickness of the large screen liquid crystal display device may be reduced and light uniformity may be improved.

In addition, since a cold cathode tube lamp is used as a light source of the lamp assembly, the lamp assembly may have a long life and have low heat dissipation, thereby improving reliability of the large screen liquid crystal display.

Claims (13)

A mold frame in which a receiving groove is formed; A reflection sheet installed on a bottom surface of the receiving groove to reflect light; A light guide plate disposed on an upper portion of the reflective sheet and having diffuse reflection parts formed on a lower surface of the reflective sheet to control an amount of light; At least two lamp assemblies disposed on at least one side of the light guide plate to emit light; Is installed on top of the light guide plate includes optical sheets for diffusing and condensing the light guided by the light guide plate, The lamp assemblies A cold cathode tube lamp having a hot electrode formed at one end and a cold electrode formed at the other end thereof; Lamp holders inserted at both ends of the cold cathode tube lamp to protect the cold cathode tube lamp; A lamp reflecting plate surrounding the cold cathode tube lamp and having one side opened and fitted to a side surface of the light guide plate; And an inverter electrically connected to the hot electrode and the cold electrode by a wire to apply a voltage to the cold cathode tube lamp, wherein the lamp assemblies have a length shorter than a side length of the light guide plate on which the lamp assemblies are to be installed. Liquid crystal display device. The liquid crystal display device of claim 1, wherein the lamp assemblies are disposed on two side surfaces of the light guide plate facing each other. 3. The lamp assembly of claim 2, wherein the lamp assemblies are A first lamp assembly installed at one end of both side surfaces of the light guide plate facing each other; And a second lamp assembly disposed at opposite ends of opposite sides of the light guide plate to be spaced apart from the first lamp assembly by a predetermined distance. The liquid crystal display of claim 3, wherein the length of the first lamp assembly and the length of the second lamp assembly are the same. 4. The light guide plate of claim 3, wherein the length of the first lamp assembly and the length of the second lamp assembly are different from each other, and face each other of the first lamp assemblies disposed on opposite sides of the light guide plate. And the second lamp assemblies are disposed on opposite sides of the liquid crystal display. 4. The method of claim 3, wherein the first lamp assembly of the lamp holders of the first and second lamp assemblies and the first lamp assembly of the first lamp assembly and the second lamp assembly in order to prevent the dark portion is generated; And one side of the lamp holders installed on the side of the second lamp assembly facing each other. 4. The method of claim 3, wherein the first lamp assembly and the one of the lamp holders of the first and second lamp assembly to prevent the formation of a dark portion at the boundary of the first lamp assembly and the second lamp assembly One side of the lamp holders installed on the side in which the second lamp assembly is facing each other, wherein the liquid crystal display device. The method of claim 3, wherein the diffuse reflection portion is densely formed in a predetermined region of the lower surface of the light guide plate corresponding to the boundary portion in order to prevent the dark portion formed in the boundary portion of the first lamp assembly and the second lamp assembly. Liquid crystal display device characterized in that. The method of claim 3, wherein in order to prevent the dark portion is generated at the boundary between the first lamp assembly and the second lamp assembly, the side of the cold cathode tube lamp facing the first lamp assembly and the second lamp assembly. And hot electrodes on opposite sides of the hot electrodes. The cold cathode tube lamp of claim 3, wherein the first lamp assembly and the second lamp assembly face each other to install the inverter on a side of the light guide plate on which the first and second lamp assemblies are not installed. And placing the hot electrodes on the opposite sides. 4. The liquid crystal display device according to claim 3, wherein at least two cold cathode tube lamps are installed in the first and second lamp assemblies in a horizontal direction with respect to the light guide plate. 4. The liquid crystal display device according to claim 3, wherein at least two cold cathode tube lamps are installed in the first and second lamp assemblies in a direction perpendicular to the light guide plate. The method of claim 1, wherein a short prevention plate protruding to a predetermined length in a predetermined area of the side wall of the side wall of the receiving groove in which the lamp assemblies are installed to prevent the lamp assemblies adjacent to each other from being shorted. Liquid crystal display device.