KR20080052918A - Backlight assemlby and flat display device including the same - Google Patents

Abstract

A backlight assembly and a flat panel display having the same are provided to prevent the bias of current in the case of adopting a parallel driving method by using a hybrid lamp of which one side is formed of a heat cathode electrode and the other side is formed of an external electrode. A backlight assembly comprises hybrid lamps(760), an inverter, a frame mode side(780), and a diffusion plate(740). A heat cathode electrode is formed at the one end of each hybrid lamp, and an external electrode is formed at the other end. The inverter supplies driving voltage to the hybrid lamps. The frame mode side fixes the hybrid lamps. The diffusion plate diffuses the light provided from the hybrid lamps.

Description

BACKLIGHT ASSEMLBY AND FLAT DISPLAY DEVICE INCLUDING THE SAME}

1 is a schematic perspective view of a hybrid lamp according to an embodiment of the present invention.

2 is an exploded perspective view of a backlight assembly according to an exemplary embodiment of the present invention.

3 is an exploded perspective view of a flat panel display device having a backlight assembly according to an exemplary embodiment of the present invention.

The present invention relates to a backlight assembly and a flat panel display device having the same.

With the recent rapid development of semiconductor technology, the demand for liquid crystal display devices having improved performance while being smaller and lighter is exploding.

Recently, liquid crystal displays (LCDs), which have been in the spotlight, have advantages such as miniaturization, light weight, and low power consumption, and as an alternative means to overcome the disadvantages of the conventional cathode ray tube (CRT). It has been attracting attention and is currently used in almost all information processing equipment that requires a display device.

In general, a liquid crystal display device applies a voltage to a specific molecular array of a liquid crystal to convert it into another molecular array, and visually changes optical properties such as birefringence, photoreactivity, dichroism, and light scattering characteristics of the liquid crystal cell emitted by the molecular array. It is a light-receiving display device which converts into a change and displays information using the modulation of the light by a liquid crystal cell.

Since the liquid crystal display is a light receiving display device, a backlight assembly for supplying light is required to display an image. The backlight assembly includes a light source that emits light. Typically, the backlight assembly uses an inverter to convert power supplied from the outside into a constant voltage and then apply the light to the light source.

Light sources include EL (Electro Luminescence), Light Emitting Diode (LED), Hot Cathode Fluorescent Lamp (HCFL), Cold Cathode Fluorescent Lamp (CCFL), External Electrode Use an fluorescent lamp (External Electrode Fluorescent Lamp, EEFL).

Among them, the hot cathode fluorescent lamp is a light source that can maximize the range of brightness by heating the filament in the electrode to emit hot electrons, thereby improving video quality and realizing high contrast ratio.

However, a separate driving method of driving the individual cathodes using a separate transformer for each lamp is currently used mainly, which leads to an increase in the cost of the inverter, thereby weakening the price competitiveness of the hot cathode fluorescent lamp.

In order to overcome such a problem, a parallel driving scheme has recently been used. The parallel driving method is to drive a plurality of lamps simultaneously with a single transformer. In this case, the number of inverter components can be reduced, thereby greatly reducing the cost.

However, when the hot cathode fluorescent lamps are driven in parallel, there may be a slight difference in the lighting start time due to the deviation between the individual lamps, and there is a possibility of overcurrent due to current draw to the lamp which is turned on even in the minute time difference.

The technical problem of the present invention is to provide a backlight assembly and a flat panel display device including the same, in which current pull does not occur even when the parallel driving method is used.

In order to solve this problem, the present invention proposes a hybrid lamp in which a hot cathode electrode is formed on one side and an external electrode is formed on the other side.

In the backlight assembly according to the exemplary embodiment of the present invention, a hybrid lamp having a hot cathode electrode formed at one end thereof and an external electrode formed at the other end thereof, an inverter applying a driving voltage to the hybrid lamp, and a frame fixing the hybrid lamp Mold side, a diffuser plate for diffusing light provided from the hybrid lamp.

A flat panel display device according to an embodiment of the present invention includes a flat panel display panel for displaying an image, a backlight assembly for supplying light to the flat panel display panel, an optical film unit positioned between the flat panel display panel and the backlight assembly, the backlight assembly The light source of is a hot cathode electrode formed at one end, and an external electrode formed at the other end.

The flat panel display may be a liquid crystal display panel.

Then, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a part of a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the other part being "right over" but also another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

1 is a schematic perspective view of a hybrid lamp according to an embodiment of the present invention.

As shown in FIG. 1, a hybrid lamp includes a glass tube 766 which is a body of a lamp, a hot cathode electrode 764 formed at one end of the glass tube 766, and an external electrode formed at the other end. 765 and a power lead wire 761 for supplying power to the hot cathode electrode 764 and the external electrode 765.

The hot cathode electrode 764 is disposed inside one end of the glass tube 766 as an internal electrode, and is composed of a lead wire 762 and a filament 763.

The external electrode 765 is formed outside of the other end of the glass tube 766. The external electrode 765 is formed of a material having electrical conductivity. The external electrode 765 may be formed by dipping the glass tube 766 in the molten electrically conductive material, or may be formed of a metal or metal alloy having electrical conductivity having a socket shape corresponding to the end shape of the glass tube 766. Can be.

When the external electrode 765 is formed in a socket shape, a conductive adhesive such as silver paste is used to fix the external electrode 765 to the end of the glass tube 766.

The glass tube 766 is filled with an inert gas including mercury (Hg). Power for driving the lamp is transmitted to the lead wire 762 through the power lead wire 761, and a current is supplied from the lead wire 762 to the filament 763.

The filament 763 to which the current is supplied is heated to emit hot electrons, and the hot electrons collide with inert gases including mercury to discharge the inert gas. Since the filament 763 is heated to emit hot electrons, it is preferable to use an ultra high temperature heat resistant metal such as tungsten or molybdenum.

Current flows to the external electrode 765 by hot electrons emitted from the filament 763. At this time, when the glass tube in which the external electrode 765 is formed forms a capacitor between the external electrode 765 and the inside of the glass tube to drive a plurality of hybrid lamps in parallel, a different balance board is used. Without the board, the current of the hybrid lamp can be prevented from being directed to the specific hybrid lamp.

2 is an exploded perspective view of a backlight assembly according to an embodiment of the present invention, which shows a backlight assembly in which hybrid lamps are arranged side by side. The structure of the backlight assembly shown in FIG. 2 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the present invention can also be applied to backlight assemblies having other structures.

The backlight assembly according to the embodiment of the present invention is made by combining the optical sheet 720, the diffusion plate 740, the hybrid lamp 760 and the frame mold side (780), hybrid lamp 760 Diffuse the light emitted from) to make it uniform and emit it in the upper direction. The bottom chassis 750 located at the bottom of the backlight assembly accommodates internal components including the hybrid lamp 760 and the frame mold side 780, and the mold frame 710 located at the top thereof includes the bottom chassis (bottom chassis) 750 is fixedly coupled.

The plurality of hybrid lamps 760 for supplying light are arranged to be fixedly spaced apart from the bottom chassis 750 by a predetermined distance, and the reflective sheet 790 is installed on the bottom surface of the bottom chassis 750 to provide a hybrid lamp ( Reflect light emitted from 760.

A light source holder (not shown) is installed at an end of the hybrid lamp 760 to fix and support the hybrid lamp 760. Covered with frame mold side 780 to secure the light source holder (not shown) again.

Light emitted from the plurality of hybrid lamps 760 is evenly spread through the diffusion plate 740. This makes it possible to distribute the light more uniformly. The brightness of the light is improved through the optical sheet 720 positioned on the diffuser plate 740 to supply the light. Accordingly, it is possible to supply light with uniformity and improved brightness.

An inverter (not shown) for applying a driving voltage to the hybrid lamp 760 is installed on the bottom of the bottom chassis 750, and is protected by covering it with a shield case (not shown). The hybrid lamp 760 is connected to the inverter through a wire (not shown) connected to the hybrid lamp 760, and the inverter applies a driving voltage to the hybrid lamp 760.

3 is an exploded perspective view of a flat panel display device having a backlight assembly according to an exemplary embodiment of the present invention, and shows a state in which a liquid crystal display panel is coupled to the backlight assembly.

Although the liquid crystal display panel is shown as an example of a flat panel display panel in FIG. 3, this is merely to illustrate the present invention and the present invention is not limited thereto. Accordingly, other types of light receiving flat panel display panels may be used. In FIG. 3, the liquid crystal display panel 500 disposed on the backlight assembly 700 is assembled with the backlight assembly 700 while covering the liquid crystal display panel 500 with the top chassis 600 to manufacture the flat panel display device.

The liquid crystal display panel assembly 400 may include a liquid crystal display panel 500, a chip on film (COF) 430 and 440 connected thereto, and a printed circuit board 410 and 420. Include. The printed circuit boards 410 and 420 may be accommodated in the side surface of the top chassis 600.

The liquid crystal display panel 500 includes a thin film transistor substrate 510 including a plurality of thin film transistors, a color filter substrate 530 disposed on the thin film transistor substrate 510, and a liquid crystal injected between the substrates. Not shown). Polarizers are attached to the upper portion of the color filter substrate 530 and the lower portion of the thin film transistor substrate 510 to polarize light passing through the liquid crystal display panel 500.

The thin film transistor substrate 510 is a transparent glass substrate on which a matrix thin film transistor is formed, a data line is connected to a source terminal, and a gate line is connected to a gate terminal. In the drain terminal, a pixel electrode made of transparent indium tin oxide (ITO) is formed as a conductive material.

When electrical signals are input from the printed circuit boards 410 and 420 to the gate lines and the data lines of the liquid crystal display panel 500 described above, electrical signals are input to the gate terminal and the source terminal of the thin film transistor. According to the input of the signal, the thin film transistor is turned on or off so that an electrical signal necessary for pixel formation is output to the drain terminal.

On the other hand, the color filter substrate 530 is disposed on the thin film transistor substrate 510. The color filter substrate 530 is a substrate in which RGB (red, green, blue) pixels, which are color pixels in which a predetermined color is expressed as light passes, are formed by a thin film process, and a common electrode made of ITO is coated on the entire surface thereof. When power is applied to the gate terminal and the source terminal of the thin film transistor and the thin film transistor is turned on, an electric field is formed between the pixel electrode and the common electrode of the color filter substrate. By the electric field, the arrangement angle of the liquid crystal injected between the thin film transistor substrate 510 and the color filter substrate 530 is changed, and the light transmittance is changed according to the changed arrangement angle to obtain a desired pixel.

The printed circuit boards 410 and 420 for receiving image signals from the outside of the liquid crystal display panel 500 and applying driving signals to the gate lines and the data lines, respectively, are each chip mounted films attached to the liquid crystal display panel 500. And (430, 440). In order to drive the flat panel display, the gate side printed circuit board 410 transmits a gate driving signal, and the data side printed circuit board 420 transmits a data driving signal. That is, the gate driving signal and the data driving signal are applied to the gate line and the data line of the liquid crystal display panel 500 through the chip mounting films 430 and 440 on which the integrated circuit chips 431 and 441 are mounted. A control board (not shown) is installed on the back of the backlight assembly 700. The control board is connected to the data side printed circuit board 420 to convert an analog data signal into a digital data signal and then supplies the same to the liquid crystal display panel 500.

The top chassis may be formed on the liquid crystal display panel assembly 400 to prevent the liquid crystal display panel assembly 400 from being separated from the backlight assembly 700 while bending the chip mounting films 430 and 440 to the side of the backlight assembly 700. 600). Although not shown in FIG. 3, a front case and a rear case are positioned at an upper portion of the top chassis 600 and a lower portion of the bottom chassis 750, respectively, to form a flat panel display device by combining them.

Although the preferred embodiments of the present invention have been described in detail above, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Accordingly, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

As in the present invention, when one side is formed of a hot cathode and the other side is formed of an external electrode, the hybrid lamp has a capacitor on its own to prevent the current from flowing in parallel operation without additional components. can do.

Claims (3)

A hybrid lamp having a hot cathode electrode formed at one end thereof and an external electrode formed at the other end thereof; An inverter for applying a driving voltage to the hybrid lamp; A frame mold side for fixing the hybrid lamp, And a diffuser plate for diffusing the light provided by the hybrid lamp. Flat panel display panel for displaying images, A backlight assembly supplying light to the flat panel display panel; An optical film unit disposed between the flat panel display panel and the backlight assembly; And a light source of the backlight assembly is a hybrid lamp having a hot cathode electrode formed at one end thereof and an external electrode formed at the other end thereof. In claim 2, The flat panel display panel is a liquid crystal display panel.

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