KR20040096186A - Back light unit and liquid crystal display device by using the same - Google Patents

Abstract

PURPOSE: A back light unit and an LCD(Liquid Crystal Display) using the back light unit are provided to control peak luminance separately from average luminance. CONSTITUTION: A back light unit includes a lamp array(41), an electrode controller(42), and a power supply(43). The lamp array includes lamps and a diffusion plate. The lamps are composed of a plurality of light emitting diodes or organic light emitting diodes. The electrode controller consists of a column electrode controller(42a) and a row electrode controller(42b) for controlling partial luminance of the lamps. The power supply provides power voltage or/and common voltage to the lamp array. The lamps are constructed in a manner that the light emitting diodes or organic light emitting diodes are arranged in column and row directions in a tiled form.

Description

BACK LIGHT UNIT AND LIQUID CRYSTAL DISPLAY DEVICE BY USING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit, and more particularly, to a backlight unit capable of improving peak luminance and a liquid crystal display using the same.

As the information society develops, the demand for display devices is increasing in various forms, and in recent years, liquid crystal display devices (LCDs), plasma display panels (PDPs), electro luminescent displays (ELDs), and vacuum fluorescent (VFD) Various flat panel display devices such as displays have been studied, and some of them are already used as display devices in various devices.

Among them, LCD is the most widely used as the substitute for CRT (Cathode Ray Tube) for mobile image display because of its excellent image quality, light weight, thinness, and low power consumption. In addition to the use of the present invention has been developed a variety of monitors, such as television and computer for receiving and displaying broadcast signals.

Such a liquid crystal display may be classified into a liquid crystal display panel displaying a video signal, a driving circuit for applying a driving signal to the liquid crystal display panel from the outside, and a backlight unit serving as a light source to the liquid crystal display panel.

Although not shown in the drawing, the liquid crystal display panel is a display device in which liquid crystal is injected between two transparent substrates (glass substrates) bonded to each other with a predetermined space, and a plurality of liquid crystal display panels arranged at regular intervals on one of the two transparent substrates. A plurality of gate lines, a plurality of data lines arranged at regular intervals in a direction perpendicular to the gate line, a plurality of pixel electrodes formed in each pixel region in a matrix form defined by the gate lines and the data lines, In accordance with the signal of the gate line, a plurality of thin film transistors for applying the signal of the data line to each pixel electrode is formed at a portion where the gate line and the data line cross each other. A color filter layer, a common electrode, and a black matrix layer are formed on the remaining substrates.

Therefore, when the turn-on signal is sequentially applied to the gate line, an image is displayed because the data signal is applied to the pixel electrode of the corresponding line.

The driving principle of the liquid crystal display device uses the optical anisotropy and polarization property of the liquid crystal. Since the liquid crystal is thin and long in structure, the liquid crystal has directivity in the arrangement of molecules, and the direction of the molecular arrangement can be controlled by artificially applying an electric field to the liquid crystal.

Accordingly, when the molecular arrangement direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and light is refracted in the molecular arrangement direction of the liquid crystal due to optical anisotropy to express image information.

Currently, active matrix LCDs (AM-LCDs) in which a thin film transistor, which is a switching element, and pixel electrodes connected to the thin film transistor are arranged in a matrix manner, are attracting the most attention due to their excellent resolution and ability to implement video.

Among the liquid crystal display devices, the passive light emitting liquid crystal display device has a back light unit used as a light source behind the liquid crystal display panel, and a CCFL (Cold Cathode Fluorescent Lamp) used as a light source of the backlight unit is In terms of its properties, luminance and lifetime are inversely related. That is, when driving at a high current to increase the brightness, the life is reduced, while to increase the life, it is difficult to achieve high luminance because it must be driven at a low current.

In practice, however, in most cases, high brightness and long life are required simultaneously.

To meet these demands, while driving a screen with a certain brightness in a screen state of a general liquid crystal display device, when driving a screen where a high brightness is required, a high current is temporarily applied to a backlight lamp to temporarily It is applying technology to widen the active area.

In addition, in the case of the liquid crystal display device, the amount of current used varies depending on the image displayed on the screen. For example, in the normally white mode, in which liquid crystal molecules are rearranged in the direction of an electric field with the application of a voltage to block incident light, the panel consumes more power as the number of bright pixels on the screen increases. As the number of dark pixels increases, the power consumption of the panel tends to increase as the number of dark pixels increases, and a method of controlling the current value of the lamp associated with the panel according to the power consumed by the panel is mainly used. .

The application of this technique requires the implementation of additional circuitry such as detecting the current consumed by the panel and modifying it to fit the variable range of the luminance control signal of the inverter driving the backlight.

The installation of such a backlight unit is inefficient in terms of thickness, weight and power consumption, and much research is still conducted.

Hereinafter, a backlight unit according to the related art will be described with reference to the accompanying drawings.

1 is a perspective view of a light guide plate type monitor for a backlight unit according to the prior art, Figure 2 is a perspective view of a direct backlight unit according to another conventional technology.

The backlight unit used as a light source of the liquid crystal display device is a method of arranging a cylindrical light emitting lamp, and is divided into a light guide plate method and a direct type method.

First, a backlight unit for a monitor manufactured according to a conventional light guide plate method (edge method) will be described.

The backlight unit for a monitor according to the prior art, as shown in FIG. 1, guides the lamp 10 as a light source for emitting light and the light emitted from the lamp 10 to be reflected to the LCD panel 14. A light guide plate 11, a diffusion sheet 12 for diffusing light emitted from the light guide plate 11 at a predetermined angle, and a prism sheet for collecting and diffusing the diffused light to the LCD panel 14 13, the LCD panel 14 formed on the top of the prism sheet 13, a fixing mechanism (not shown) formed on the lower part of the light guide plate 11, and light transmitted to the fixing mechanism. It is composed of a reflecting plate 16 which reflects the panel 14 to minimize the loss of light.

In addition to the above configuration, the lamp reflector 18 surrounding the outside of the lamp 10 except for the light incident surface of the light guide plate 11 to reduce the loss of the light emitted from the lamp 10 emitted to the light incident surface of the light guide plate 11. And a lamp holder 17 formed at both ends of the lamp 10 to fix the lamp 10 at 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 unit according to the light guide plate method (edge method) can be applied to a notebook PC in addition to the monitor for placing the lamps on both sides of the light guide plate, and when applied to the notebook PC, the lamp is disposed only on one side of the light guide plate.

The light guide plate method is to install a light emitting lamp on the outside of the light guide plate and to distribute the light to the entire surface by using the light guide plate, the light emitting lamp is installed on the side of the light guide plate, there is a problem that the brightness is low because the light must pass through the light guide plate. . In addition, high optical design and processing technology for the light guide plate is required for uniform distribution of light intensity.

Next, a direct backlight unit manufactured according to another conventional technique will be described.

The conventional direct backlight unit 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 as shown in FIG. Light scattering means 5a, 5b, 5c disposed between 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 As illustrated in FIG. 1, the grooves are fitted in grooves formed on both surfaces of the outer case 3.

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

That is, a power lead wire 9 connected to one electrode of the light emitting lamp and a power lead wire 9a connected to the other electrode are connected to one connector (not shown), and one of the voltage lead wires 9 and 9a is an outer case. It is bent to the bottom of (3) and connected to the connector.

However, such a direct backlight according to the related art has a connector connected to a power supply lead of a light emitting lamp and connected to a driving circuit. Since the connector is individually required for each light emitting lamp, wiring is complicated and for the purpose of reducing the thickness of the backlight. By bending the power lead wire and connecting the connector, not only the work efficiency is reduced, but also a separate work is required for this, which increases the process time and the productivity.

In addition, in order to connect the electrode and the connector, a hole penetrating the outer case must be drilled and both electrodes of the light emitting lamp must be inserted into the hole so that both electrodes of the light emitting lamp are exposed to the outside of the outer case. Falling and maintenance of the luminous lamp is difficult.

In addition, the direct backlight unit arranges a light emitting lamp on a flat surface, and since the shape of the light emitting lamp appears on the liquid crystal panel, the distance between the lamp and the liquid crystal panel should be maintained, and the light scattering means is provided for the uniform distribution of light. There is a limit to thinning because it must be arranged.

Further, as the panel becomes larger, the area of the light exit surface of the backlight unit also increases. When the direct backlight unit is enlarged, the light exit surface is not flat unless the light scattering means secures a sufficient thickness. For this reason, the thickness of the light scattering means must be sufficiently secured.

As such, the light guide plate method and the direct type method have the above-mentioned disadvantages, and therefore, in the liquid crystal display device where brightness is more important than the screen thickness, the direct type backlight unit is mainly used. In the liquid crystal display device in which thickness is important, a light guide plate type backlight unit is mainly used.

In addition to the above problems, the backlight unit should be able to be used in a stable state of the mechanical structure capable of realizing appropriate brightness for various liquid crystal panel sizes.

However, in the future of the LCD TV era, the CRT has an average luminance of 150 to 200 nit and a peak luminance of 1200 to 1600 nit, so that the peak luminance can be adjusted separately from the average luminance, whereas the backlight unit used in the conventional LCD TV is continuously. A method of increasing only the average luminance is used.

As a result, the backlight unit used in the conventional LCD TV has problems such as glare caused by an increase in average brightness, increased power consumption, and deteriorated liquid crystal panel due to heat generation.

The present invention has been made to solve the above problems, and in particular, an object of the present invention is to provide a backlight unit that can adjust the peak brightness separately from the average brightness and a liquid crystal display device using the same.

1 is a perspective view of a backlight unit according to the prior art

2 is a perspective view of a backlight unit according to another conventional technology

3 is a block diagram of a liquid crystal display device using a backlight unit according to an embodiment of the present invention.

4 is an overall plan view of a signal sensing unit and a backlight unit for each region according to an exemplary embodiment of the present invention.

5 is a structural sectional view of a unit lamp of the backlight unit;

6 is a cross-sectional view illustrating an electrical connection relationship between lamps in region 'A' of FIG.

Explanation of symbols on the main parts of the drawings

30: liquid crystal panel 31: timing controller

32: signal sensing unit for each region 33: video signal output unit

40: backlight unit 41: (O) LED array unit

42: electrode control unit 42a: column electrode control unit

42b: row electrode control unit 43: power supply unit

44 panel 50 lamp

51 terminal for external electrode 52 first electrode layer

53: (O) LED layer 53a: first conductive layer

53b: light emitting layer 53c: second conductive layer

54 second electrode layer 55 diffuser plate

56: protective layer

The backlight unit of the present invention for achieving the above object is a lamp array comprising a plurality of lamps of a plurality of LED (Light Emitting Diode) or OLED (Organic Light Emitting Diode) having a diffusion plate, and the partial And an electrode control unit including a column electrode control unit and a row electrode control unit for controlling brightness, and a power supply unit for outputting a power voltage and / or a common voltage to the electrode control unit and the lamp array unit.

The lamp is characterized in that the LED (Light Emitting Diode) or the OLED (Organic Light Emitting Diode) is arranged in a plurality of tiles having a tiled (tiled type) in the column and row direction.

The unit lamp of the lamp array unit may include a terminal for soldering external electrodes attached to one region of the panel, a first electrode layer in contact with the terminal for external electrodes, and white light on the first electrode layer (O) An LED layer, a second electrode layer formed on the (O) LED layer, a diffusion plate formed on the second electrode layer, and the first electrode layer and the (O) LED layer so that a part of the terminal for the external electrode is exposed. And a protective layer surrounding the second electrode layer and the diffusion plate.

The first electrode layer is characterized in that composed of aluminum (Al) or silver (Ag).

The second electrode layer may be formed of indium tin oxide (ITO), tin oxide (TO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), or transparent conductive oxide (TCO). Characterized in that composed of a transparent conductor such as.

The (O) LED layer is characterized by being composed of n-type and p-type first and second conductive layers having different conductivity, and a light emitting layer formed therebetween.

The light emitting layer is composed of InGaN, InGaP, or InGaAs when the LED layer is formed, and is composed of a polymer and a low molecular EL (Electroluminescent) when the OLED layer is formed.

The liquid crystal display device using the backlight unit configured as described above comprises a sensing unit which receives an image signal from the outside and senses the brightness of each region signal, an upper and lower substrates and a liquid crystal layer filled therebetween; And a backlight unit having the configuration of claim 1 to receive the sensing result of the sensing unit and partially generate peak luminance.

The electrode control unit may further include an over driving circuit (ODC) unit configured to output the sensing result to the sensor unit.

The first important component of the above-mentioned backlight unit is a lamp.

Such lamps are EL (Electroluminescent), Light Emitting Diode (LED), Organic Light Emitting Diode (OLED), Cold Cathode Fluorescence Lamp (CCFL), Hot Cathode Fluorescent Lamp and External Electrode Fluorescent Lamp (EEFL).

Recently, light emitting diodes (LEDs) and OLEDs are in the spotlight as backlight units of liquid crystal displays, and LEDs or OLEDs have a longer life than ELs and cold cathode tubes and operate at 5V DC, and thus do not require a separate inverter. .

Hereinafter, a backlight unit and a liquid crystal display using the same according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

3 is a block diagram of a liquid crystal display device using a backlight unit according to an exemplary embodiment of the present invention, and FIG. 4 is a plan view of the signal sensing unit and the backlight unit according to an exemplary embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a unit lamp of the backlight unit, and FIG. 6 is a cross-sectional view illustrating an electrical connection relationship between the lamp of region 'A' of FIG. 4.

As shown in FIG. 3, a liquid crystal display device using a backlight unit according to an exemplary embodiment of the present invention includes a liquid crystal panel 30, a backlight unit 40, and an area-specific signal sensing unit 32. Reference numerals 31 and 33 are timing controllers and video signal output units, respectively.

Although not shown in the drawing, the liquid crystal panel 30 includes upper and lower glass substrates and a liquid crystal layer filled therebetween.

In this case, the lower glass substrate includes a plurality of gate lines arranged in one direction at a predetermined interval, a plurality of data lines arranged at regular intervals in a direction perpendicular to the gate lines, and the gate lines and the data lines intersect each other. A plurality of pixel electrodes formed in a matrix form in each defined pixel region, and a plurality of thin film transistors (TFTs) which are switched by signals of the gate lines to transfer the signals of the data lines to the pixel electrodes are formed. .

On the upper glass substrate, a black matrix layer is formed to block light except for the pixel region, and R (Red), G (Green), and B (Blue) cells transmit only light of a specific wavelength band and absorb the remaining light. The color filter layer and the common electrode for implementing an image are comprised.

The liquid crystal panel 30 may be configured by a transverse electric field method in which a common electrode is formed on a lower glass substrate.

In addition, although not shown in the drawing, a driving circuit unit for supplying a driving signal and a data signal to the liquid crystal panel 30 is further provided, wherein the driving circuit unit inputs a data signal to each data line of the liquid crystal panel 30. A data driver, a gate driver for applying a gate driving pulse to each gate line of the liquid crystal panel 30, and each display data at a timing suitable for the data driver and gate driver of the liquid crystal panel 30 to reproduce the screen. And a timing controller 31 for formatting and outputting a clock and various control signals.

3 and 4, the backlight unit 40 is positioned on the rear surface of the liquid crystal panel 30 and includes a plurality of light emitting diode (LED) or organic light emitting diode (OLED) lamps 50. A lamp array unit (hereinafter referred to as (O) LED array unit 41), an electrode control unit 42 composed of a column electrode control unit 42a and a row electrode control unit 42b, and the electrode control unit The power supply unit 43 outputs a power voltage or a common voltage to the unit 42 and the (O) LED array unit 41.

In addition, the area-specific signal sensing unit 32 senses the brightness of the image signal for each location so as to generate peak luminance and outputs the brightness to the electrode control unit 42.

Reference numeral 33 is an image signal output unit, and the image signal output unit 33 is an external input signal for inputting image signal data and power voltage for each position to the signal sensing unit 32 and the power unit 43 for each region.

Hereinafter, a backlight unit capable of displaying peak luminance among the components of the liquid crystal display will be described in detail.

As described above, the backlight unit includes an (O) LED array unit 41, an electrode control unit 42, and a power supply unit 43, of which (O) LED array unit 41 is diffused. The lamp 50 includes a plurality of LEDs (Light Emitting Diode) or OLED (Organic Light Emitting Diode) having a plate, and a panel 44 on which the lamp 50 is disposed.

In this case, the lamp 50 includes a plurality of LEDs (Light Emitting Diodes) or OLEDs (Organic Light Emitting Diodes) for supplying light to the liquid crystal panel 30 having a tiled shape in a column and a row direction. .

As shown in FIGS. 4 and 5, the lamps 50 contact the external electrode terminal 51 for soldering attached to one region of the panel 44 and the external electrode terminal 51 to receive a signal. The first electrode layer 52 which transmits and serves as a reflecting plate, the (O) LED layer 53 formed to emit white light on the first electrode layer 52, and the (O) LED layer 53. The second electrode layer 54 formed on the second electrode layer, the diffusion plate 55 formed on the second electrode layer 54, and the first electrode layer 52 and (O) are exposed so that a part of the external electrode terminal 51 is exposed. A protective layer 56 surrounding the LED layer 53, the second electrode layer 54, and the diffusion plate 55 is formed.

At this time, a low voltage Vxn is applied to the first electrode layer 52 through the external electrode terminal 51, and a column voltage Vym is applied to the second electrode layer 54. In this case, the voltages applied to the first and second electrode layers 52 and 54 may be interchanged.

The first electrode layer 52 is made of aluminum (Al) or silver (Ag), and the (O) LED layer 53 includes the first and second conductive layers 53a and 53c and the light emitting layer formed therebetween. 53b), and the second electrode layer 54 provides good contact with the metal to facilitate the flow of electricity.

Transparent conductors such as Indium Tin Oxide (ITO), Tin Oxide (TO), Indium Zinc Oxide (IZO), Indium Tin Zinc Oxide (ITZO) or Transparent Conductive Oxide (TCO) It is composed.

At this time, the first and second conductive layers 53a and 53c constituting the (O) LED layer 53 are composed of any one of n-type and p-type semiconductor layers having different conductivity, and the light emitting layer 53b is an LED. The layer is composed of InGaN, InGaP, or InGaAs, and the OLED layer is composed of a polymer and a low molecular EL (Electroluminescent).

The (O) LED layer 53 configured as described above is driven by diode operation, and electrons are excited and emit light according to the voltage difference applied to the first and second conductive layers 53a and 53c.

In addition, the lamp 50 may not be arranged in a one-to-one correspondence with each pixel area of the liquid crystal panel 30, and may be arbitrarily defined and arranged to have a predetermined area, and the lamp 50 may include first and second electrode layers. The brightness is adjusted by the voltage difference of (52, 54).

The electrode adjusting unit 42 controls the lamps 50 arranged in the column and row directions of the (O) LED array unit 41 to adjust the brightness of the lamp 50. As a control unit for giving the peak brightness, it was composed of a column electrode control unit 42a and a row electrode control unit 42b.

The column electrode controller 42a applies column voltages Vy1 to Vym to the lamps 50 arranged on the first to mth column lines, respectively, and the row electrode controller 42b is arranged on the first to nth lines. The low voltages Vx1 to Vxn are applied to the lamps 50 arranged on the low line, respectively.

The power supply unit 43 outputs a power supply voltage to the column electrode control unit 42a and the row electrode control unit 42b, and simultaneously supplies the column common voltage Vy-com and the low common voltage Vx to the plurality of lamps 50. -com).

Referring to the arrangement of the lamps 50 arranged in the row direction of the backlight unit having the above configuration, as shown in FIG. 6, through the external electrode terminals 51 of the lamps 50 arranged in the row direction, The low common voltage Vx-com and the low voltages Vx1 to Vxn corresponding to the corresponding line are input in parallel to the first electrode layer 52, and the column common voltage Vy-com and corresponding to the second electrode layer 54. Each column voltage Vy1 to Vyn corresponding to the line is input in parallel.

The backlight unit having the above configuration can emit light by distinguishing the average brightness and the peak brightness, which will be described below.

First, the image signal output unit 33 applies an image signal and a power supply voltage input from the outside to the signal sensing unit 32 and the power unit 43 for each region.

Thereafter, the power supply unit 43 outputs the column common voltage Vy-com and the low common voltage Vx-com to the lamps 50 arranged in the column and row directions so that the backlight unit displays the average brightness. do.

After sensing the brightness of the image signal for each region through the region-specific signal sensing unit 32 in addition to the average luminance, if a specific region is detected to be brighter than the average, the sensing result is applied to the electrode controller 42 and the electrode controller In (42), a column and a low voltage corresponding to the sensed level are respectively output to a specific region corresponding to the sensed result. As a result, the specific region sensed is brighter than the other region having the average brightness, resulting in peak luminance.

The peak luminance region brighter than the average luminance may be output by adjusting its level.

In the configuration of FIG. 4 described above, instead of outputting the column common voltage Vy-com and the low common voltage Vx-com from the power supply unit 43, the ODC in the electrode control unit 42 is over driving. The circuit unit may be further configured, and the area-specific signal sensing unit 32 may be configured to output the sensing result to the ODC unit.

According to the above configuration, only a specific region may be brightened by additionally inputting a voltage to the row and column lines of the region sensed to be brighter than the average level by the OCD.

The present invention can be applied to all kinds of equipment (TV, notebook, etc.) using the liquid crystal display device, and the scanning back light method is also easy to adopt, and is not limited to the above embodiment. It includes various forms that can be easily derived by those skilled in the art.

The backlight unit of the present invention and the liquid crystal display device using the same have the following effects.

By partially controlling the brightness of the backlight unit by external signal control, the peak brightness may be displayed in a specific region to be distinguished from the average brightness.

As a result, conventional problems such as glare caused by increasing the average brightness as a whole, increased power consumption, and deteriorated liquid crystal panel due to heat generation can be prevented, and the image quality of the liquid crystal display device can be compensated. Can be.

Claims (9)

A lamp array unit including a plurality of lamps of a light emitting diode (LED) or an organic light emitting diode (OLED) having a diffusion plate, An electrode controller comprising a column electrode controller and a row electrode controller for controlling partial brightness of the lamps; And a power supply unit configured to output a power voltage and / or a common voltage to the electrode control unit and the lamp array unit. The method of claim 1, The lamp is a backlight unit, characterized in that the LED (Organic Light Emitting Diode) or the OLED (Organic Light Emitting Diode) is arranged in a plurality of tiles having a tiled (tiled type) in the column and row direction. The method of claim 1, The unit lamp of the lamp array unit includes a terminal for soldering external electrodes attached to one region of the panel; A first electrode layer in contact with the external electrode terminal; An (O) LED layer formed on the first electrode layer to emit white light; A second electrode layer formed on the (O) LED layer; A diffusion plate formed on the second electrode layer, And a protective layer surrounding the first electrode layer, the (O) LED layer, the second electrode layer, and the diffusion plate so that a part of the external electrode terminal is exposed. The method of claim 3, wherein The first electrode layer is a backlight unit, characterized in that composed of aluminum (Al) or silver (Ag). The method of claim 3, wherein The second electrode layer may be formed of indium tin oxide (ITO), tin oxide (TO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), or transparent conductive oxide (TCO). Back light unit, characterized in that consisting of a transparent conductor such as. The method of claim 3, wherein And said (O) LED layer comprises n-type and p-type first and second conductive layers having different conductivity, and a light emitting layer formed therebetween. The method of claim 6, The light emitting layer is composed of InGaN, InGaP, or InGaAs when the LED layer is configured, and when the OLED layer is composed of a polymer, a low molecular EL (Electroluminescent). Sensing unit for receiving the image signal from the outside to sense the brightness of the signal for each area, A liquid crystal panel comprising upper and lower substrates and a liquid crystal layer filled therebetween; And a backlight unit having the configuration of claim 1 so as to receive the sensing result of the sensing unit and partially generate peak luminances. The method of claim 8, The electrode control unit may further include an over driving circuit (ODC) unit, and the sensing unit may be configured to output a sensing result to the ODC unit. .