KR20060000976A - Back light unit of liquid crystal display device - Google Patents

Abstract

The backlight unit of the liquid crystal display according to the present invention comprises: a plurality of unit surface emitting lamps each positioned in a lamp cell area divided into a matrix; An outer case fixing and supporting the unit surface emitting lamps; It characterized in that it comprises a plurality of electrodes drawn out of the outer case to drive the local / light-emitting unit light emitting lamp.

According to the present invention, the unit surface light emitting lamp is arranged in a matrix form under the liquid crystal panel, and each electrode for local / dividing driving the unit surface light emitting lamp is drawn out to the outside, thereby simplifying the backlight split driving. Image quality is improved by performing, and there is an advantage that the repair of each lamp is easy.

Description

Back light unit of liquid crystal display device

1 is a perspective view of a conventional edge type backlight.

2 is a perspective view of a conventional direct backlight.

3 is a perspective view briefly showing a structure of a backlight unit according to an embodiment of the present invention.

4 is a perspective view briefly showing a structure of a backlight unit according to another embodiment of the present invention.

5 is a perspective view briefly showing a structure of a backlight unit according to another embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

30: outer case 32: lamp cell

34 unit light emitting lamp 36 negative electrode

38 positive electrode

The present invention relates to a backlight unit of a liquid crystal display device, and more particularly, to a direct type backlight unit in which a unit surface light emitting lamp is provided in a matrix form.

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 light weight 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 Panels (PDPs) and Electro Luminescence Displays (ELDs) using electroluminescent effects are used. Among them, research on liquid crystal displays is being actively conducted.

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

Since most of the liquid crystal display devices are light-receiving devices that display images by controlling the amount of light coming from the outside, a separate light source, that is, a back light, for irradiating light to the LCD panel is necessary.

In general, a backlight used as a light source of a liquid crystal display device is a method of arranging a cylindrical light emitting lamp, and is classified 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.

The edge method in which the lamp unit is installed on the side of the light guide plate is mainly applied to a relatively small liquid crystal display device such as a monitor of a laptop computer and a desktop computer.

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, and a plurality of lamps are arranged in a row on the lower surface of the diffuser plate to direct light directly to the front of the LCD panel. 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.

However, the liquid crystal display device adopting the direct method is used as a large monitor or a television, so it takes longer to use than a laptop computer and the number of lamps is larger, so the liquid crystal of the direct method is lower than the edge type liquid crystal display device. It is more likely that a lamp that will not turn on will appear due to the failure and life of the lamp in the display.

In addition, in the edge method in which the lamp units are installed on both side surfaces of the light guide plate, due to the life and failure of the lamp, for example, when only one lamp is not turned on, only the brightness on the screen is lowered.                         

However, in the direct method, since a plurality of lamps are installed at the bottom of the screen, for example, due to the life and failure of the lamp, if one lamp does not light up, the part where the lamp is not lit becomes significantly darker than the other part. The part that does not appear immediately on the screen.

For this reason, since the lamp is frequently replaced in the direct type liquid crystal display device, the direct type liquid crystal display device should have an easy structure for disassembling and assembling the lamp unit.

As described above, the backlight arrayed in an edge method and a direct method using a cylindrical light emitting lamp has a problem in that light efficiency is lowered due to decomposition and assembly of the light emitting lamp and heat generation of the light emitting lamp itself.

Hereinafter, a conventional backlight will be described with reference to the accompanying drawings.

1 is a perspective view of a conventional edge type backlight, Figure 2 is a perspective view of a conventional direct type backlight.

First, the conventional edge-type backlight can be used for a monitor and a notebook PC. Hereinafter, the backlight for the monitor will be described.

As shown in FIG. 1, the monitor backlight includes a lamp 10 as a light source for emitting light and a light guide plate 11 for guiding and reflecting the light emitted from the lamp 10 to the LCD panel 14. A diffusion sheet 12 for diffusing the light emitted from the upper portion of the light guide plate 11 at a predetermined angle, a prism sheet 13 for condensing the diffused light and transferring the light to the LCD panel 14; The LCD panel unit 14 formed on the top of the prism sheet 13, the fixing unit (not shown) formed on the lower portion of the light guide plate 11, and the light transmitted to the fixing unit. It is composed of a reflecting plate 16 to reflect the light to minimize the loss of light.

In addition to the above configuration, in order to reduce the loss of the outgoing light of the lamp 10 exiting the light guide plate 11, the light reflection plate 18 surrounding the outside of the lamp 10 except for the light entrance surface of the light guide plate 11 and In addition, a lamp holder 17 formed at both ends of the lamp 10 is further provided to fix the lamp 10 to a predetermined position and prevent excessive entry of the light guide plate 11 into the lamp 10 area. In the above, a plurality of diffusion sheets 12 may be formed as necessary.

The backlight for the monitor manufactured by the edge method is to arrange the lamps on both sides of the light guide plate. As described above, the backlight according to the edge method can be applied to the notebook PC in addition to the monitor. In this case, the lamp is placed only on one side of the light guide plate. Let's do it.

Next, as shown in FIG. 2, the conventional direct backlight includes a plurality of light emitting lamps 1, an outer case 3 for fixing and supporting the light emitting lamps 1, and the light emitting lamps 1. Light scattering means 5a, 5b, 5c disposed between the liquid crystal panels (not shown).

The light scattering means (5a, 5b, 5c) is to prevent the shape of the light emitting lamp from appearing on the display surface of the liquid crystal panel and to provide a light source having an overall uniform brightness distribution, in order to enhance the light scattering effect A plurality of diffusion sheets, diffusion plates, and the like are disposed between the cells.

The inner surface of the outer case 3 is disposed with a reflector 7 so that the light emitted from the light emitting lamp 1 can be concentrated to the display unit of the liquid crystal panel, which is to maximize the utilization efficiency of the light.

The light emitting lamp 1 is a Cold Cathode Fluorescent Lamp (CCFL), and electrodes are disposed at both ends of a tube to emit light when power is applied to the electrodes, and both ends of the light emitting lamp 1 are discharged. 2 is fitted in the grooves formed on both sides of the outer case 3.

Power lead wires 9 and 9a for transmitting power for driving the lamp are connected to both electrodes of the light emitting lamp, and the power lead wires 9 and 9a are connected to a separate connector and connected to the driving circuit. Therefore, a separate connector is required for each light emitting lamp 1.

That is, the power lead wire 9 connected to one electrode of the light emitting lamp and the power lead wire 9a connected to the other electrode are connected to one connector, and one of the power lead wires 9 and 9a is connected to the outer case 3. Bends down to connect with the connector.

On the other hand, the light emitting lamp may be configured by using an EEFL (External Electrode Fluorescent Lamp) having electrodes on both ends of the tube instead of the Cold Cathode Fluorescent Lamp (CCFL).

However, the backlight unit of the conventional lamp structure has a disadvantage in that it is impossible to cope with it when it wants to display high luminance partially.                         

Of course, in the case of the direct type backlight unit, it is possible to partially control the brightness by sequentially lighting each lamp, but there is a problem in that the partial peak brightness using this is problematic because the horizontal or vertical axis in which the lamps are located are all brightened.

According to the present invention, the unit surface light emitting lamps are arranged in a matrix form under the liquid crystal panel, and each electrode for local / dividing driving of the unit surface light emitting lamps is drawn out to the outside. It is an object of the present invention to provide a backlight unit of a liquid crystal display device which is improved and facilitates repair of each lamp.

In order to achieve the above object, a backlight unit of a liquid crystal display according to the present invention includes: a plurality of unit surface light emitting lamps each positioned in a lamp cell area divided into a matrix; An outer case fixing and supporting the unit surface emitting lamps; It characterized in that it comprises a plurality of electrodes drawn out of the outer case to drive the local / light-emitting unit light emitting lamp.

The apparatus may further include light scattering means disposed between the unit surface light emitting lamps and the liquid crystal panel, wherein the unit surface light emitting lamps may be formed in a curved tube in a plurality of lamp cell regions, respectively. A pair of electrodes is characterized in that it is drawn out of the case.

In addition, a plurality of electrodes are disposed on the lateral side and the longitudinal side of the outer case, respectively, and the arranged anode and cathode are characterized in that they are connected to the corresponding unit surface light emitting lamps, respectively.

In addition, the positive electrode and the negative electrode are characterized in that the positive (+) and negative (-) voltage corresponding to half of the voltage required to drive the unit surface light emitting lamp connected thereto is applied simultaneously.

In addition, each electrode provided in the horizontal side is a single electrode line to apply a voltage to the unit surface light emitting lamp connected to the electrode line collectively, each electrode provided in the longitudinal side is individually withdrawn from the corresponding unit surface light emitting lamp And a separate voltage is applied.

Alternatively, a plurality of electrodes are disposed on one side of the outer case, respectively, and the anodes and cathodes are respectively connected to unit surface emitting lamps corresponding thereto, or each of the plurality of anodes on one side of the outer case. And an electrode serving as a cathode, wherein the arranged anode and cathode are connected to a unit surface light emitting lamp corresponding thereto.

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

3 is a perspective view briefly illustrating a structure of a backlight unit according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the direct type backlight unit according to the present invention fixes a plurality of unit surface emitting lamps 34 and respective unit surface emitting lamps 32 positioned in a region of lamp cells 32 divided into a matrix. The outer case 30 for supporting and supporting the plurality of electrodes, the plurality of electrodes drawn out of the outer case 30 to locally / dividing the unit surface emitting lamp 34, and the unit surface emitting lamp 34. Light scattering means (not shown) disposed between the liquid crystal panels (not shown).

The light scattering means is to prevent the shape of the unit surface light emitting lamp 34 from appearing on the display surface of the liquid crystal panel and to provide a light source having a uniform brightness distribution as a whole. A plurality of diffusion sheets, diffusion plates, and the like are disposed therebetween.

In addition, a reflection plate (not shown) is disposed on the inner surface of the outer case 30 so that light generated from each unit surface light emitting lamp 34 can be concentrated to the display unit of the liquid crystal panel, which maximizes light utilization efficiency. To do this.

In the present invention, the unit surface emitting lamps 34 are each provided in a curved form in a plurality of lamp cell 32 regions partitioned in a matrix form as shown, and each one for driving the lamp 34 is provided. The pair of electrodes 36 and 38 are led out of the case.

Here, the unit surface emitting lamp 34 may be implemented as a cold cathode fluorescent lamp (CCFL), in which case the power is supplied to the electrodes 36 and 38 connected to both ends of the curved tube. When it is applied, it emits light.

As shown in FIG. 3, in the present invention, a plurality of electrodes 38 and a cathode 36 are disposed on the lateral and longitudinal sides of the case, respectively. The unit surface light emitting lamp 34 is driven by applying a voltage.

When the voltage required for driving the unit surface emitting lamps 34 is referred to as Vth, the present invention is driven by simultaneously applying 1 / 2Vth of the half of the unit surface emitting lamps 34 at the anode 38 and the cathode 36 at the same time. It features.

That is, in order to drive the unit surface light emitting lamp 34 provided on the upper left side, -1 / 2Vth may be applied to the first electrode on the side and + 1 / 2Vth to the first electrode on the side.

Thus, in the present invention, each unit surface light emitting lamp 34 has both ends of the lamp connected to a predetermined anode 38 and a cathode 36, and to the connected anode 38 and cathode 36. By applying a constant voltage, local / divisional driving is possible for each unit surface light emitting lamp 34.

Here, each electrode 36 provided at the longitudinal side is a single electrode line, and a voltage is collectively applied to each unit surface light emitting lamp 34 connected to the electrode line, and each electrode 38 provided at the horizontal side is The respective unit surface emitting lamps 34 are individually drawn out and connected to each other, so that respective voltages are applied.

This enables local / divided driving of each unit surface emitting lamp described above.

On the other hand, the unit surface emitting lamp according to the present invention is not limited to the Cold Cathode Fluorescent Lamp (CCFL) described above, in addition to the EEFL (External Electrode Fluorescent Lamp) having electrodes on both ends of the tube (tube) It can also be configured using.

According to the present invention, it is possible to improve local control and peak brightness of the backlight by using a plurality of unit surface emitting lamps.

That is, after arranging the plurality of unit surface emitting lamps in the form of a matrix, an area requiring a brighter or darker image within a frame is detected by analyzing an input image, and a signal for the area is sent to the backlight unit. The image quality can be improved by modulating the unit surface emitting lamp located in the area.

4 is a perspective view briefly illustrating a structure of a backlight unit according to another exemplary embodiment of the present invention.

However, the same reference numerals are used for the same components as the embodiment shown in FIG. 3, and description thereof will be omitted.

Referring to FIG. 4, there is a difference in that all of the lines of the electrode 36 provided in the longitudinal direction are positioned to move laterally in comparison with FIG. 3. The position and operation method of the unit surface light emitting lamp are described in FIG. 3. Same as bar.

As such, by moving and positioning all the electrodes 36 and 38 to one side, the inverter unit for driving the unit surface light emitting lamp 34 can be concentrated in one place. As a result, the rear structure of the liquid crystal display module including the backlight unit can be concentrated. To make things simpler.                     

However, the structure may change the direction of the unit surface emitting lamps corresponding to a specific lamp cell 32 row as shown in FIG. 5 and may form the positions of the electrodes 38 corresponding to each other.

This is to separately drive the inverter that emits the most heat in the liquid crystal display module.

According to the present invention, the unit surface light emitting lamp is arranged in a matrix form under the liquid crystal panel, and each electrode for local / dividing driving the unit surface light emitting lamp is drawn out to the outside, thereby simplifying the backlight split driving. Image quality is improved by performing, and there is an advantage that the repair of each lamp is easy.

Claims (8)

A plurality of unit surface emitting lamps each positioned in a lamp cell area divided into a matrix; An outer case fixing and supporting the unit surface emitting lamps; And a plurality of electrodes drawn out of the outer case to locally / dividingly drive the unit surface light emitting lamp. The method of claim 1, And a light scattering means disposed between the unit surface emitting lamps and the liquid crystal panel. The method of claim 1, The unit surface light emitting lamp is formed of a curved tube in each of a plurality of lamp cell regions, and a pair of electrodes for driving the lamp are led out of the case. The method of claim 1, A plurality of electrodes are disposed on the lateral side and the vertical side of the outer case, respectively, and the arranged anode and cathode are respectively connected to a unit surface light emitting lamp corresponding thereto. unit. The method of claim 4, wherein And a positive (+) and a negative (-) voltage corresponding to half of the voltage required for driving the unit surface emitting lamp connected thereto is simultaneously applied to the anode and the cathode. The method of claim 4, wherein Each electrode provided on the lateral side is a single electrode line to apply a voltage to the unit surface light emitting lamp connected to the electrode line collectively, Each electrode provided as a vertical side is individually drawn from the corresponding unit surface light emitting lamp and a separate voltage is applied to the backlight unit of the liquid crystal display device. The method of claim 1, A plurality of electrodes are disposed on one side of the outer case, respectively, as the anode and the cathode, and the arrayed anode and cathode are respectively connected to a unit surface light emitting lamp corresponding thereto. The method of claim 1, A plurality of electrodes are disposed on one side of the outer case, respectively, as the anode and the cathode, and the arrayed anode and cathode are respectively connected to a unit surface light emitting lamp corresponding thereto.

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