KR20060028928A - Back light unit and lcd driving method using thereof - Google Patents

Abstract

The backlight unit of the present invention includes an optical sheet and a diffusion plate; A lamp divided into a plurality of " '" shapes disposed in the surface direction on the lower side of the diffusion plate; Characterized in that it comprises a reflecting plate and a case configured on the lower side of the lamp.

In addition, the backlight unit of the present invention includes an optical sheet and a diffusion plate; Lamps coated with electrodes on an inner outer side of a plurality of external electrode fluorescent lamps (EEFLs) disposed below the diffuser plate in a plane direction of the diffuser plate; Characterized in that it comprises a reflecting plate and a case configured on the lower side of the lamp.

In addition, the present invention provides a liquid crystal panel for displaying an image; A backlight unit according to any one of claims 1 to 6, which supplies light to the liquid crystal panel; A liquid crystal display comprising: dividing the lamps included in the backlight unit into a plurality of regions and dividing the lamps in a dimming manner to which an adaptive brightness intensifier (AI) is applied. It is a device driving method.

Backlit, split, large screen, electrode structure, AI

Description

BACK LIGHT UNIT AND LCD DRIVING METHOD USING THEREOF}

1 shows a backlight with a conventional two divided " U " shaped lamp;

2 is a perspective view showing the structure of a backlight unit of a first embodiment of the present invention;

FIG. 3 is an enlarged view of a region A shown in FIG. 2; FIG.

4 is a perspective view showing the structure of a backlight unit of a second embodiment of the present invention;

FIG. 5 is an enlarged view of a region B shown in FIG. 4; FIG.

<Description of Symbols for Main Parts of Drawings>

100: lamp 130: lamp holder

110: external electrode fluorescent lamp 140: electrode

150: low pressure internal electrode 151: high pressure internal electrode

152: high voltage external electrode 200: diffusion plate

210: optical sheet 240: reflector

300: case 500: liquid crystal panel

The present invention relates to a backlight unit, and more particularly, to a backlight unit structure and a method of driving a liquid crystal display device having the same.

Recently, liquid crystal display devices, which are one of the flat panel display devices that are continuously attracting attention, are liquid.

A device that changes the optical anisotropy by applying an electric field to a liquid crystal that combines the liquidity and optical properties of the crystal.It has a low power consumption, a small volume, a large size, and a high definition compared to a conventional cathode ray tube. have.

In general, since most 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 for illuminating the liquid crystal panel, that is, a backlight unit, is necessarily required. Such a backlight unit is classified into an edge type and a direct light type according to the location where the lamp unit is installed.

The edge type is a lamp is installed on the side of the light guide plate for guiding the light, the lamp unit is a lamp that emits light, a lamp holder that is inserted at both ends of the lamp to protect the lamp, and wraps the outer peripheral surface of the lamp 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 type 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, a long durability life, and is advantageous for thinning of the liquid crystal display device.

On the other hand, the direct type has been mainly developed as the liquid crystal display is large screen, and a plurality of lamps are arranged in a row on the lower surface of the diffusion plate to direct light directly to the front of the liquid crystal display panel. Such a direct type 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 type.

Recently, as the size of LCD screens increases, the demand for high brightness backlight units, which have been split, is increasing.As a part of implementing the above, multiple lamps are disposed below the display screen or one lamp is bent. The research and development of the direct type backlight unit is continuing.

The fluorescent lamps used in the liquid crystal display are classified according to the positions of the electrodes. The cold cathode fluorescent lamps (CCFLs) and the hot cathode fluorescent lamps (HCFLs) in which the electrodes are located inside the fluorescent lamps are classified. There is an external electrode fluorescent lamp (EEFL) with an electrode outside. Common fluorescent lamps are hot cathode fluorescent lamps, and the backlight units used in laptops and monitors use cold cathode fluorescent lamps with low heat and long life.

1 is a view showing a backlight unit having a conventional two-part "U" shaped lamp.

As shown in FIG. 1, the conventional lamp 1 is a cold cathode fluorescent lamp, is manufactured in a “U” shape, has a phosphor coated on an inner wall thereof, and has an electrode that is electrically conductive at both ends thereof. Not shown) is formed.

In addition, both electrodes (not shown) of the light emitting lamp 1 are connected to a lamp connector 3 that transmits power for driving the lamp and is connected to the driving circuit. At this time, both electrodes (not shown) of one lamp 1 are adjacent to each other, and are tied to one lamp connector 3 connected thereto. Such a plurality of lamps 1 are inserted into the backlight unit for the liquid crystal display device to emit light.

Although not shown, the plurality of “U” shaped lamps 1 may be mounted in the backlight unit, and the plurality of lamps 1 may be fixed in the backlight unit through the support of the lower surface of the backlight unit, and light may be transmitted. It is composed of transparent supports so that it can be done.

In addition, the interval between the lamps 1 can be kept constant, it may be provided with a guide portion (5) to facilitate the insertion and removal to the backlight unit.

One of the plurality of lamps 1 is provided with a DC / AC inverter for converting the DC voltage provided from the AC adapter or the battery into an AC voltage having a constant frequency and voltage level suitable for the lamp (1). The terminal of the inverter is integrated with the high voltage side and the low voltage side. When the connector 3 is connected to a terminal of such an inverter, an alternating current flows through the lamp 1 to cause the lamp 1 to emit light.

In order to increase the dynamic contrast ratio required for a large screen liquid crystal display, a dimming method that divides a screen into several areas and applies an adaptive bright intensity (AI) is required. The lamp can only be divided into up / down or left / right two divisions, which is not suitable for expressing a thrilling and smooth image in a large screen liquid crystal display.

SUMMARY OF THE INVENTION An object of the present invention is to provide a backlight unit capable of dividing into a plurality of regions suitable for a large liquid crystal display in a liquid crystal display.

The present invention provides an optical sheet and a diffusion plate; A lamp divided into a plurality of " '&quot; shapes disposed in the surface direction on the lower side of the diffusion plate; It is a backlight unit characterized in that it comprises a reflecting plate and a case which is configured under the lamp.

The present invention also provides an optical sheet and a diffusion plate; Lamps coated with electrodes on an inner outer side of a plurality of external electrode fluorescent lamps (EEFLs) disposed below the diffuser plate in a plane direction of the diffuser plate; It is a backlight unit characterized in that it comprises a reflecting plate and a case which is configured under the lamp.

In addition, the present invention provides a liquid crystal panel for displaying an image; A backlight unit according to any one of claims 1 to 6, which supplies light to the liquid crystal panel; A liquid crystal display comprising: dividing the lamps included in the backlight unit into a plurality of regions and dividing the lamps in a dimming manner to which an adaptive brightness intensifier (AI) is applied. It is a device driving method.

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

<First Embodiment>

FIG. 2 is a perspective view showing the structure of the backlight unit according to the first embodiment of the present invention, and FIG. 3 is an enlarged view of region A shown in FIG.

As shown in FIG. 2, the backlight unit according to the first exemplary embodiment of the present invention includes a liquid crystal panel 500 for displaying an image by controlling light transmitted therethrough, and light at regular intervals below the liquid crystal panel 500. It consists of an optical sheet 210 for condensing the light to increase the brightness, and a diffuser plate 200 for scattering the light on the lower side of the optical sheet 210 to irradiate the front of the optical sheet 210 with uniform light.

Here, the optical sheet 210 and the diffusion plate 200 are stacked.

And the lower side of the diffusion plate 200 is composed of a plurality of divided lamps 100 for emitting light, the light is directed to the front of the lower side of the divided lamps 100 to the front to the loss of light The reflection plate 240 is configured to increase the light efficiency by reducing the light, and a case 300 for supporting the components is configured under the reflection plate 240.

It can be seen that the lamp 100, which is a core component of the backlight unit for the liquid crystal display device, is disposed in a plurality of divided "c" shapes corresponding to the entire light incident surface of the diffuser plate 200. That is, a plurality of lamps having a length corresponding to the light incident surface of the diffuser plate 200 are not disposed, but a plurality of “c” shaped divided lamps 100 are formed in blocks of the diffuser plate 200. Placed in the plane direction has a structure so that the light is uniformly irradiated on the entire light incident surface of the diffusion plate 200.

As such, unlike the conventional lamp arrangement, the present invention is a structure in which a plurality of "c" shaped lamps 100 are arranged in the plane direction of the diffusion plate 200 in units of blocks. In the connecting portion between the divided lamp 100 for interconnection between the 100, as shown in Figure 3, the lamp holder 130 for the connection of the divided lamp 100 is further disposed.

That is, in the related art, since the "U" shaped lamp is disposed in a double division, the lamp holders are disposed at both ends of the lamps to fix the lamps, thereby fixing the lamps, but the backlight unit for the liquid crystal display device according to the present invention is fixed. The lamp holder 130 in the is disposed at the left or right end of the divided lamp 100 in the middle of the backlight serves to fix the divided lamp 100, as well as the divided lamp 100 as described above It is also arranged in the connection portion between) to connect the divided lamp 100.

In addition, one end of the divided lamp 100 is bent, the divided lamp 100 is formed in a "c" shape as a whole (see Figure 2), the bent portion is an "L" shape (See FIG. 3).

Looking at the shape of the bent portion in more detail, as described above, when the plurality of divided lamps 100 are arranged in the plane direction of the diffusion plate 200, each of the connection between the divided lamps 100 The electrode portion 140, which is the non-light emitting portion of the divided lamp 100, is positioned. Therefore, light does not occur in the central portion, which is a connection portion between the divided lamps 100, on which the electrode portion 140, which is the non-light emitting portion, is located. This results in dark areas.

Accordingly, the divided lamps are formed in an “L” shape to bend the electrode parts 140, which are the non-light-emitting parts of the divided lamps 100, and fixedly connected to the lamp holder 130, thereby not emitting light of the electrode parts 140. The dark area by the site is removed and light is uniformly distributed on the diffusion plate 200. In addition, the shape of the bent portion is not limited to the "L" shape, it will be apparent to those skilled in the art that various modifications are possible.

In addition, the lamp holder 130 is preferably made of a transparent material, that is, transparent plastic so that the light reflected on the reflecting plate 240 can pass.

The reflector 240 is formed by coating a material having a good reflectance such as silver, titanium, and polymer on a material having good thermal conductivity such as aluminum. The case 300 is made of a material having good thermal conductivity such as aluminum.

In the direct type backlight unit configured as described above, since the shape of the divided lamp 100 appears in the liquid crystal panel 500, a constant distance must be maintained between the divided lamp 100 and the liquid crystal panel 500. Therefore, an optical space is formed between the divided lamp 100 and the liquid crystal panel 500.

The optical sheet 210 and the diffusion plate 200 are stacked in the optical space so that light can smoothly reach the liquid crystal panel 500.

Accordingly, the backlight unit of the liquid crystal display according to the first exemplary embodiment of the present invention is a direct type backlight unit having a structure in which a plurality of “c” shaped lamps 100 are provided in block units.

That is, the backlight unit according to the first embodiment of the present invention uses dimming by applying an adaptive brightness intensifier (AI) for dividing and driving a screen into a plurality of areas for realizing a dynamic image of a large screen of a liquid crystal display. It is a backlight unit that can divide the block unit of the screen suitable for the method.

The dimming method uses a dimming circuit that can adjust the brightness of the lamp, and the backlight inverter for the liquid crystal display uses analog dimming and burst dimming functions to control the brightness of the lamp. Doing.

Burst dimming circuits usually carry a burst dimming frequency of 200 Hz at the switching frequency of the main switch of 100 Hz, and adjust the on-duty of the burst dimming frequency to determine the on / off period of the main switch. Therefore, the switching is intermittent to control the brightness of the lamp.

The analog dimming circuit adjusts the brightness of the lamp by varying only the reference voltage of the error amplifier when feeding back the current flowing through the lamp in the form of voltage.

However, when the burst dimming circuit and the analog dimming circuit are used independently of each other, the brightness of the lamp cannot be dimmed completely from 0 to 100%. Therefore, the burst dimming function and the analog dimming function are generally used in parallel.

By adopting such a dimming method, a first embodiment of the present invention proposes a liquid crystal display driving method for dividing and driving the lamps in a dimming method to which AI is applied by using a backlight unit including a divided lamp.

That is, the first embodiment of the present invention divides the screen into a plurality of areas by using the backlight unit and the backlight unit which can divide the screen unit into blocks for realizing a dynamic image of the large screen of the liquid crystal display device. The present invention provides a dimming method having an adaptive brightness intensifier (AI).

Second Embodiment

4 is a perspective view illustrating a structure of a backlight unit according to a second exemplary embodiment of the present invention, and FIG. 5 is an enlarged view of region B shown in FIG. 4.

Since the structure of the backlight unit of the second embodiment of the present invention is the same as the first embodiment described above except for the lamp, the description thereof will be omitted.

As shown in FIG. 4, the lamp 110 of the backlight unit according to the second embodiment of the present invention includes an external electrode fluorescent lamp (EEFL) of the conventional direct type lamp structure on the surface of the diffusion plate 200. It is a structure arranged in the direction.

The lamp 110 of the backlight unit is electrically connected to the external electrode 152 formed at both ends of the conventional fluorescent lamp by inserting it into a wire terminal (not shown). As a result, the voltage applied to the wires causes the lamp 110 to emit light due to the voltage difference between the external electrodes 152 formed at both ends of the lamp 110.

However, an internal electrode for electrically conducting the lamp 110 to the position of the lamp holder 130 of the first embodiment (see Fig. 2) in order to provide an AI applicable multi-division lamp suitable for a large dynamic image. 150 and 151 were formed (see FIG. 4).

The internal electrodes 150 and 151 are positioned between the external electrodes 152 located at the outer side of the lamp 110, and are mainly composed of a low pressure internal electrode 150 and a high pressure internal electrode 151.

In addition, the external electrodes 152 and the internal electrodes 150 and 151 may have high voltages from the left side to prevent the divided lamps 110b from emitting light so that the luminance between the divided lamps 110a and 110b is not constant. The external electrode 152 and the low pressure internal electrode 150, the low pressure internal electrode 150 and the high pressure internal electrode 151, the high pressure internal electrode 151 and the low pressure internal electrode 150, and the low pressure inside The electrode 150 and the high pressure external electrode 152 are arranged in this order.

As shown in FIGS. 4 and 5, the external electrode 152 and the internal electrodes 150 and 151 are positioned around the lamp holder 130 at the position of the lamp holder 130 of the first embodiment (see FIG. 2). It was formed by coating the electrode along.

That is, in the related art, since the "U" shaped lamp is disposed in a double division, electrodes are disposed only at both ends of the lamp to supply power to the lamp, thereby providing power to the lamp, but according to the present invention. The electrodes 150, 151, and 152 of the backlight unit are disposed inside and outside the lamp 110 to supply power to the lamp 110.

That is, by forming an electrode (150, 151) by coating the electrode around the inner tube of the conventional external electrode fluorescent lamp (EEFL), it is possible to divide the screen multiple, resulting in a reduced lamp Due to the length (110a, 110b), the driving voltage is lowered, it is possible to increase the brightness.

That is, the backlight unit according to the second embodiment of the present invention uses dimming by applying an adaptive brightness intensifier (AI) for dividing and driving a screen into a plurality of areas for realizing a dynamic image of a large screen of a liquid crystal display. It is a backlight unit that can divide the block unit of the screen suitable for the method.

The dimming method uses a dimming circuit that can adjust the brightness of the lamp, and the backlight inverter for the liquid crystal display uses analog dimming and burst dimming functions to control the brightness of the lamp. Doing.

Burst dimming circuits usually carry a burst dimming frequency of 200 Hz at the switching frequency of the main switch of 100 Hz, and adjust the on-duty of the burst dimming frequency to determine the on / off period of the main switch. Therefore, the switching is intermittent to control the brightness of the lamp.

The analog dimming circuit adjusts the brightness of the lamp by varying only the reference voltage of the error amplifier when feeding back the current flowing through the lamp in the form of voltage.

However, when the burst dimming circuit and the analog dimming circuit are used independently of each other, the brightness of the lamp cannot be dimmed completely from 0 to 100%. Therefore, the burst dimming function and the analog dimming function are generally used in parallel.

By adopting such a dimming method, a second embodiment of the present invention proposes a liquid crystal display device driving method for dividing and driving the lamps in a dimming method to which AI is applied by using a backlight unit including a divided lamp.

That is, the second embodiment of the present invention divides the screen into a plurality of areas by using the backlight unit and the backlight unit which can divide the screen unit into blocks for realizing a dynamic image of the large screen of the liquid crystal display device. The present invention provides a dimming method having an adaptive brightness intensifier (AI).

In addition, the backlight unit according to the second embodiment of the present invention forms an internal electrode by coating the electrode around the inner tube of the conventional external electrode fluorescent lamp, thereby enabling a plurality of screen division, resulting in a reduced lamp length. Due to the low driving voltage, it is possible to increase the brightness.

The present invention provides a backlight unit capable of dividing a block unit of a screen and an AI (Adaptive brightness Intensifier) for driving a screen divided into a plurality of areas using the backlight unit for realizing a dynamic image of a large screen of a liquid crystal display device. By providing a dimming method having a), it is effective to realize a dynamic image of a large screen liquid crystal display.

In addition, the backlight unit of the present invention forms an internal electrode by coating the electrode around the inner tube of the conventional external electrode fluorescent lamp, so that it is possible to divide a plurality of screens, and as a result, the driving voltage is lowered due to the reduced lamp length This has the effect of increasing the luminance.

In addition, the present invention is not limited to the 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 (7)

An optical sheet and a diffusion plate; A lamp divided into a plurality of " '&quot; shapes disposed in the surface direction on the lower side of the diffusion plate; And a reflecting plate and a case formed under the lamp. The method of claim 1, And a lamp holder further disposed at a connection portion between the lamps. The method of claim 2, The lamp holder is a backlight unit, characterized in that the plastic or metal of a transparent material. The method of claim 1 The reflector is a backlight unit, characterized in that the coating by using any one of silver (silver), titanium (Titanium) or a polymer (Polymer) on a heat conductor such as aluminum. An optical sheet and a diffusion plate; Lamps coated with electrodes on an inner outer side of a plurality of external electrode fluorescent lamps (EEFLs) disposed below the diffuser plate in a plane direction of the diffuser plate; And a reflecting plate and a case formed under the lamp. The method of claim 5, wherein The electrode coated on the inner outside of the external electrode fluorescent lamp includes a high pressure electrode and a low pressure electrode. A liquid crystal panel displaying an image; A backlight unit according to any one of claims 1 to 6, which supplies light to the liquid crystal panel; In the liquid crystal display device comprising: And dividing the lamps included in the backlight unit into a plurality of regions, and dividing the lamps by dimming using an adaptive brightness intensifier (AI).

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