KR100830991B1 - Light emitting device and liquid crystal display with the light emitting device as back light unit - Google Patents

Abstract

The present invention provides a light emitting device having an improved structure and a liquid crystal display using the light emitting device as a backlight unit in order to suppress heat generation of the light emitting device and thus thermal deformation of the liquid crystal panel assembly. The light emitting device according to the present invention includes a front substrate and a rear substrate which are disposed to face each other and constitute a vacuum container, first electrodes formed on one surface of the front substrate, and a first upper portion of the first electrodes with an insulating layer therebetween. Second electrodes formed along a direction crossing the electrodes, electron emission parts electrically connected to any one of the first electrodes and the second electrodes, a light reflecting film formed on one surface of the rear substrate; And a fluorescent layer formed on the light reflecting film. In this case, the first electrodes, the second electrodes, and the insulating layer are formed of a transparent material.

Electron emission part, cathode electrode, gate electrode, fluorescent layer, light reflecting film, anode electrode, liquid crystal panel assembly

Description

Light emitting device and liquid crystal display using the light emitting device as a backlight unit {LIGHT EMITTING DEVICE AND LIQUID CRYSTAL DISPLAY WITH THE LIGHT EMITTING DEVICE AS BACK LIGHT UNIT}

1 is a cross-sectional view of a light emitting device according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view of the front substrate and the electron emission unit shown in FIG.

FIG. 3 is an enlarged perspective view of the front substrate and the electron emission unit shown in order to explain a modification of the electron emission unit, and is shown in an upside down direction.

4 is a partially enlarged cross-sectional view of the rear substrate and the light emitting unit, which are shown for explaining a modification of the light emitting unit.

5 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.

6 is a block diagram of a configuration for driving a liquid crystal display according to an exemplary embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a light emitting device that emits light using an electron emission characteristic by an electric field, and a liquid crystal display device using the light emitting device as a backlight unit.

Recently, a liquid crystal display, which is one type of flat panel display, has been widely used in place of the cathode ray tube. The liquid crystal display has a characteristic of changing the amount of light transmission for each pixel using the dielectric anisotropy of the liquid crystal whose twist angle changes according to the applied voltage.

Such a liquid crystal display basically includes a liquid crystal panel assembly and a backlight unit for providing light to the liquid crystal panel assembly, and the liquid crystal panel assembly receives light emitted from the backlight unit and transmits the light by the action of the liquid crystal layer. Or a predetermined image is implemented by blocking.

The backlight unit may be classified according to the type of light source, and one of them is known as a cold cathode fluorescent lamp (CCFL). Since the CCFL is a linear light source, the light generated by the CCFL is evenly distributed toward the liquid crystal panel assembly through the optical members such as the diffusion sheet and the diffusion plate and the prism sheet.

However, in the CCFL method, since the light generated by the CCFL passes through the optical member, considerable light loss occurs, and power consumption is high because the light must be emitted at a high intensity from the CCFL in consideration of the light loss. In addition, the CCFL method is difficult to apply to a large display device of 30 inches or more because it is difficult to large area structure.

As a conventional backlight unit, a light emitting diode (LED) method is known. A plurality of LEDs are usually provided as a point light source, and are combined with optical members such as a reflective sheet, a light guide plate, a diffusion sheet, a diffusion plate, and a prism sheet to constitute a backlight unit. This LED method has the advantages of fast response speed and excellent color reproducibility, but has a disadvantage of high price and large thickness.

Accordingly, recently, a field emission type backlight unit that emits light using electron emission characteristics by an electric field has been proposed as a backlight unit to replace the CCFL method and the LED method. The field emission type back light unit is a surface light source, has the advantage of low power consumption, large size, and does not require a complicated optical member.

A typical field emission backlight unit includes a vacuum container including a front substrate, a rear substrate, and a sealing member, cathode electrodes and electron emission portions provided on one surface of the rear substrate, a fluorescent layer provided on one surface of the front substrate, An anode electrode. The electron emission unit emits electrons by an electric field formed by the voltage difference between the cathode electrode and the anode electrode, and the emitted electrons collide with the fluorescent layer of the corresponding portion to emit light.

However, in the conventional field emission type backlight unit, since a light emitting unit having a large amount of heat is provided on the front substrate facing the liquid crystal panel assembly, cooling is not easy. As a result, there is a high possibility that the backlight unit is damaged or the liquid crystal panel assembly is deformed due to heat generation, and the luminous efficiency is lowered as the fluorescent layer is exposed to high temperature for a long time.

As such, the conventional backlight unit has its own problems depending on the type of light source. In addition, the conventional backlight unit has a problem that it is difficult to meet the image quality improvement required for the liquid crystal display because the entire screen is always turned on at a constant brightness when driving the liquid crystal display.

For example, when the liquid crystal panel assembly displays an arbitrary screen including a bright portion and a dark portion according to an image signal, the backlight unit applies light of different intensities to the region displaying the bright portion and the region displaying the dark portion. If it is provided, it is possible to display a screen having excellent dynamic contrast.

However, the above-described backlight unit cannot implement the above functions, and thus the conventional liquid crystal display has a limitation in increasing the dynamic contrast ratio of the screen.

Accordingly, an object of the present invention is to solve the above problems, and an object of the present invention is to provide a light emitting device capable of quickly dissipating heat generated during driving to the outside to suppress breakage due to heat generation and thermal deformation of a liquid crystal panel assembly. There is provided a liquid crystal display device using a light emitting device as a backlight unit.

Another object of the present invention is to provide a light emitting device capable of dividing a screen into a plurality of regions and independently controlling the light intensity of each divided region, and a liquid crystal display capable of increasing the dynamic contrast ratio of the screen by using the light emitting apparatus as a backlight unit. To provide a device.

In order to achieve the above object, the present invention,

The front substrate and the rear substrate which are disposed to face each other and constitute a vacuum container, the first electrodes formed on one surface of the front substrate, and the direction intersecting the first electrodes on the first electrodes with an insulating layer therebetween. The second electrodes formed along with each other, electron emission parts electrically connected to any one of the first electrodes and the second electrodes, a light reflecting film formed on one surface of the rear substrate, and a fluorescence formed on the light reflecting film. A light emitting device comprising a layer, wherein the first electrodes, the second electrodes, and the insulating layer are formed of a transparent material.

The first and second electrodes may be formed of any one of indium tin oxide (ITO) and indium zinc oxide (IZO), and may further include an opaque auxiliary electrode formed of a metal.

The electron emission unit may include at least one of a carbonaceous material and a nanometer size material.

The light reflecting film may be formed to a thickness of 0.5 to 3㎛, and may be connected to the anode lead portion located outside the vacuum container to function as an anode electrode.

On the other hand, the light emitting unit may further include a transparent anode electrode positioned between the light reflecting film and the fluorescent layer.

The front substrate and the rear substrate may be positioned at intervals of 5 to 20 mm, and the light emitting device may further include an anode voltage applying unit for applying a DC voltage of 10 kV or more to the light reflecting layer or the anode electrode.

In addition, the present invention, in order to achieve the above object,

A liquid crystal display device including a light emitting device having the above-described configuration and a liquid crystal panel assembly positioned in front of the light emitting device to receive light emitted from the light emitting device to display an image.

The liquid crystal panel assembly forms a plurality of pixels along the row direction and the column direction, and the light emitting device forms a smaller number of pixels than the liquid crystal panel assembly along the row direction and the column direction.

The liquid crystal panel assembly forms M pixels in a row direction and N pixels in a column direction, where M and N may be set to an integer of 240 or more.

The light emitting device forms M 'pixels in a row direction and N' pixels in a column direction, where M 'and N' may be set to any integer of 2 to 99.

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

1 is a cross-sectional view of a light emitting device according to an exemplary embodiment of the present invention, and FIG. 2 is an enlarged perspective view of the front substrate and the electron emission unit illustrated in FIG.

First, referring to FIG. 1, the light emitting device 10 according to the present exemplary embodiment includes a front substrate 12 and a rear substrate 14 disposed to face each other in parallel at a predetermined interval. Sealing members 16 are disposed at the edges of the front substrate 12 and the rear substrate 14 to bond the two substrates, and the inner space is evacuated with a vacuum of approximately 10 ^-6 Torr so that the front substrate 12 and the rear substrate are spaced apart. 14 and the sealing member 16 constitute a vacuum container.

The front substrate 12 and the rear substrate 14 have an effective area contributing to the actual visible light emission inside the sealing member 16 and an invalid area surrounding the effective area. The effective area of the front substrate 12 is provided with an electron emission unit 18 for electron emission, and the effective area of the rear substrate 14 is provided with a light emission unit 20 for visible light emission.

The electron emission unit 18 includes first and second electrodes formed along a direction crossing each other, and electron emission portions electrically connected to any one of the first and second electrodes. do. The first electrodes and the second electrodes serve as driving electrodes, and serve as one of the scan electrode and the data electrode according to an application signal.

Referring to FIG. 2, in the present exemplary embodiment, the electron emission unit 18 includes cathodes 22 formed in a stripe pattern along one direction of the front substrate 12 and a cathode with an insulating layer 24 interposed therebetween. Gate electrodes 26 are formed in a stripe pattern along a direction crossing the cathode electrodes 22 on the electrodes 22, and electron emission parts 28 electrically connected to the cathode electrodes 22.

The cathode electrodes 22 and the gate electrodes 26 are formed of a transparent electrode such as indium tin oxide (ITO) or indium zinc oxide (IZO), and the insulating layer 24 is formed of a transparent insulating material. As a result, when visible light is emitted from the light emitting unit 20 provided on the rear substrate 14, the visible light passes through the transparent gate electrodes 26, the insulating layer 24, and the cathode electrodes 22 to transmit the front substrate 12. A liquid crystal panel assembly (not shown) attached to the outside.

In this case, since the transparent electrode such as ITO or IZO has a larger electric resistance than the metal electrode, as shown in FIG. 3, the cathode electrode 22 and the gate electrode 26 are opaque auxiliary electrodes 30 made of metal in some regions. , 32). The auxiliary electrodes 30 and 32 are formed to have a fine width so as not to substantially affect the visible light transmittance of the electron emission unit 18 '.

The gate electrodes 26 may be arranged side by side in the row direction of the front substrate 12, and may function as scan electrodes by receiving a scan driving voltage. The cathode electrodes 22 may be arranged side by side in the column direction of the front substrate 12, and may function as data electrodes by receiving a data driving voltage.

Openings 261 and 241 are formed in the gate electrode 26 and the insulating layer 24 at each crossing region of the cathode electrode 22 and the gate electrode 26 to expose a portion of the surface of the cathode electrode 22. The electron emission part 28 is positioned on the cathode electrode 22 inside the opening 241.

The electron emission unit 28 may be formed of materials emitting electrons when a electric field is applied in a vacuum, such as a carbon-based material or a nanometer (nm) size material. The electron emitter 28 may include, for example, carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, C ₆₀ , silicon nanowires, or mixtures thereof. Chemical vapor deposition or sputtering may be applied.

On the other hand, the electron emission portion may be formed of a tip structure having a pointed tip mainly made of molybdenum (Mo) or silicon (Si).

In the above structure, one intersection region of the cathode electrode 22 and the gate electrode 26 may correspond to one pixel region of the light emitting device 10, or two or more intersection regions may correspond to one pixel region of the light emitting device 10. Can be. In the second case, two or more cathode electrodes 22 and / or two or more gate electrodes 26 corresponding to one pixel area are electrically connected to each other to receive the same driving voltage.

Referring to FIG. 1, the light emitting unit 20 includes a light reflection film 34 formed on the rear substrate 14 and a fluorescent layer 36 formed on the light reflection film 34. The fluorescent layer 36 may be formed of a white fluorescent layer or a combination of red, green, and blue fluorescent layers.

The white fluorescent layer may be formed on the entire rear substrate 14 or may be divided and positioned in a predetermined pattern such that one white fluorescent layer is positioned in each pixel area. The red, green, and blue fluorescent layers are separated and placed in a predetermined pattern in one pixel area. In the drawing, a case in which a white fluorescent layer is positioned on the entire rear substrate 14 is illustrated.

The light reflection film 34 is made of a metal having excellent light reflectance, and is typically made of an aluminum film. In the present exemplary embodiment, the light reflecting film 34 may be densely formed to have a thickness of about 0.5 μm to 3 μm because electron transmission does not have to be considered, and the light emitting efficiency of the fluorescent layer 36 is increased due to the high light reflectance.

A part of the light reflection film 34 is drawn out of the vacuum container to form the anode lead portion 38, and may be applied as an anode voltage to function as an anode electrode. The anode electrode is an acceleration electrode for drawing an electron beam, and is applied with a high voltage of several to several tens of kilovolts (kV) to maintain the fluorescent layer 36 in a high potential state.

On the other hand, as shown in FIG. 4, the light emitting unit 20 ′ may further form a separate anode electrode 40 between the light reflecting film 34 and the fluorescent layer 36. The anode electrode 40 is formed of a transparent electrode such as ITO or IZO, a part of which is drawn out of the vacuum container to form the anode lead portion 38 '. At this time, the light reflecting film 34 is formed only inside the vacuum container.

Referring back to FIG. 1, spacers 42 are disposed between the front substrate 12 and the rear substrate 14 to support the compressive force applied to the vacuum vessel and to keep the distance between the two substrates constant. Spacers 42 are positioned outside the pixel area between gate electrodes 26. In the drawings, one spacer is shown for convenience.

The light emitting device 10 having the above-described configuration is driven by supplying a predetermined voltage to the cathode electrodes 22, the gate electrodes 26, and the light reflection film 34 from outside the vacuum container.

That is, when the cathode electrode 22 and the gate electrode 26 are applied with a predetermined driving voltage, an electric field is generated around the electron emission part 28 in the pixel region where the voltage difference between the cathode electrode 22 and the gate electrode 26 is greater than or equal to a threshold. Electrons (indicated by e ⁻ in FIG. 1) are emitted from them. The emitted electrons are attracted by the high voltage applied to the light reflecting film 34 and collide with the corresponding fluorescent layer 36 to emit light.

Visible light emitted from the fluorescent layer 36 (indicated by vl in FIG. 1) is transmitted through the transparent gate electrodes 26, the insulating layer 24, the cathode electrodes 22, and the front substrate 12 so that the front substrate ( 12) provided as a liquid crystal panel assembly (not shown) located outside. In this process, the light reflecting film 34 reflects the visible light emitted toward the rear substrate 14 among the visible light emitted from the fluorescent layer 36 toward the front substrate 12 to increase the luminous efficiency of the fluorescent layer 36.

In addition, in the present embodiment, the front substrate 12 and the rear substrate 14 are positioned at intervals of 5 to 20 mm, preferably 10 to 20 mm, and a high voltage of 10 kV or more is applied to the light reflection film 34. Accordingly, the light emitting device 10 according to the present exemplary embodiment may obtain an electron emission amount of 5 mW / cm ² or more per unit area, and may realize luminance of approximately 10,000 cd / m ² or more in the center of the effective area. In FIG. 1, reference numeral 44 denotes an anode voltage applying unit for applying an anode voltage to the anode lead unit 38.

As described above, in the light emitting device 10 of the present exemplary embodiment, the electron emission unit 18 is disposed on the front substrate 12 and the light emission unit 20 is disposed on the rear substrate 14, thereby adjusting the electron beam emission direction and the visible light emission direction. They are set in opposite directions and implement the following effects according to the above-described configuration.

In the light emitting device 10 of the present embodiment, since the light emitting unit 20 having a large amount of heat is provided on the rear substrate 14, cooling of the light emitting device 10 can be facilitated, and as a result, The heat can be quickly released to the outside to prevent breakage of the light emitting device 10 due to heat. In addition, thermal deformation of the liquid crystal panel assembly due to heat generation of the light emitting device 10 can be effectively suppressed, and the light emitting efficiency of the fluorescent layer 36 can be maintained high by lowering the temperature of the fluorescent layer 36.

In the conventional light emitting device in which the light emitting unit is provided on the front substrate, the fluorescent layer temperature is approximately 70 ° C. during driving, but in the light emitting device 10 according to the present embodiment, the fluorescent layer 36 is approximately 40 ° C. during driving. Confirmed.

5 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment in which the light emitting device having the above-described configuration is used as a backlight unit.

Referring to FIG. 5, the liquid crystal display device 50 according to the present exemplary embodiment includes a liquid crystal panel assembly 52 having arbitrary pixels in a row direction and a column direction, and is positioned behind the liquid crystal panel assembly 52 so that the liquid crystal panel assembly ( 52, a light emitting device 10 that provides light. Any known liquid crystal panel assembly may be applied to the liquid crystal panel assembly 52, and the light emitting device 10 of the above-described embodiment functions as a backlight unit.

An optical member (not shown) such as a diffusion plate or a diffusion sheet may be disposed between the liquid crystal panel assembly 52 and the light emitting device 10 as necessary.

The row direction may be defined as one direction of the liquid crystal display 50, for example, a horizontal direction of a screen implemented by the liquid crystal display 50, and the column direction may be another direction of the liquid crystal display 50. As a result, the LCD may be defined in a vertical direction of the screen implemented by the liquid crystal display device 50.

In particular, in the present embodiment, the light emitting device 10 forms a smaller number of pixels than the liquid crystal panel assembly 52 along the row direction and the column direction so that one pixel of the light emitting device 10 has two or more liquid crystal panel assemblies 52. To correspond to the pixels.

That is, when the number of pixels of the liquid crystal panel assembly 52 in the row direction and the number of pixels of the liquid crystal panel assembly 52 in the column direction are M and N, respectively, M and N may be defined as an integer of 240 or more. If the number of pixels of the light emitting device 10 in the row direction and the number of pixels of the light emitting device 10 in the column direction are M 'and N', respectively, M 'and N' are any integer of 2 to 99. Can be defined as

By the above-described configuration, the light emitting device 10 provides light of different intensities to the pixel group of the liquid crystal panel assembly 52 corresponding to each pixel, thereby improving the dynamic contrast of the screen.

6 is a block diagram of a configuration for driving a liquid crystal display device.

Referring to FIG. 6, the liquid crystal display of the present embodiment is connected to the liquid crystal panel assembly 52, the gate driver 102 and the data driver 104 connected to the liquid crystal panel assembly 52, and the data driver 104. And a gray voltage generator 106, a light emitting device 10, and a signal controller 108 for controlling them.

The liquid crystal panel assembly 52 includes a plurality of signal lines G ₁ -G _n , D ₁ -D _m as viewed in an equivalent circuit, and a plurality of pixels PX connected to the signal lines and arranged in a substantially matrix form. ). The signal lines G ₁ -G _n and D ₁ -D _m are a plurality of gate lines G ₁ -G _n for transmitting a gate signal (also called a “scan signal”), and a plurality of data lines for transmitting a data signal. (D ₁ -D _m ).

Each pixel PX, for example, the i-th (i = 1,2, ... n) gate line G _i and the j-th (j = 1,2, ... m) data line D _j The pixel 54 connected to includes a switching element Q connected to the signal lines G _i and D _j , a liquid crystal capacitor Clc, and a storage capacitor Cst connected thereto. Holding capacitor Cst can be omitted as needed.

A switching element (Q) is a three-terminal element such as thin film transistors included in liquid crystal panel assembly 52, a lower substrate (not shown), the control terminal is connected to a gate line (G _i), an input terminal is data It is connected to the line D _j , and the output terminal is connected to the liquid crystal capacitor Clc and the storage capacitor Cst.

The gray voltage generator 106 generates two sets of gray voltages (or a set of reference gray voltages) related to the transmittance of the pixel PX. One of the two sets has a positive value for the common voltage Vcom, and the other set has a negative value.

A gate driver 102, the gate lines of the liquid crystal panel assembly _{(52) (G 1 -G n} ) and is connected to the gate turn-on voltage (Von) and the gate line Gate a gate signal which is a combination of a turn-off voltage (Voff) (G ₁ -G _n ).

The data driver 104 is connected to the data lines D ₁ -D _m of the liquid crystal panel assembly 52 and selects a gray voltage from the gray voltage generator 106 and uses the data line D ₁ -D as a data signal. _m ). However, when the gray voltage generator 106 provides only a predetermined number of reference gray voltages instead of providing all of the voltages for all grays, the data driver 104 divides the reference gray voltages so that the gray voltages for all grays are divided. Generate and select the data signal from it.

The signal controller 108 controls the gate driver 102, the data driver 104, the light emitting device controller 110, and the like. The signal controller 108 receives an input image signal R, G, B and an input control signal for controlling the display thereof from an external graphic controller (not shown).

The input image signals R, G, and B contain luminance information of each pixel PX, and luminance has a predetermined number, for example, 1024 (= 2 ¹⁰ ), 256 (= 2 ⁸ ), or 64 ( = 2 ⁶ ) There are grays. Examples of the input control signal include a vertical sync signal Vsync, a horizontal sync signal Hsync, a main clock MCLK, and a data enable signal DE.

The signal controller 108 appropriately processes the input image signals R, G, and B based on the input image signals R, G, and B and the input control signals according to the operating conditions of the liquid crystal panel assembly 52, and controls the gate. After generating the signal CONT1 and the data control signal CONT2, the gate control signal CONT1 is sent to the gate driver 102, and the data control signal CONT2 and the processed image signal DAT are transmitted to the data driver Export to 104). In addition, the signal controller 108 transmits the gate control signal CONT1, the data control signal CONT2, and the processed image signal DAT to the light emitting device controller 110.

The light emitting device 10 includes a light emitting device controller 110, a column driver 112, a scan driver 114, and a display unit 116.

The display unit 116 includes a plurality of scan lines S ₁ -S _p for transmitting a scan signal, a plurality of column lines C ₁ -C _q for transferring a column signal, and a plurality of light emitting pixels EPX. . Each of the plurality of light emitting pixels EPX is positioned in a region defined by scan lines S ₁ -S _p and column lines C ₁ -C _q intersecting the scan lines. Scan lines S ₁ -S _p are connected to scan driver 114, and column lines C ₁ -C _q are connected to column driver 112. In addition, the scan driver 114 and the column driver 112 are connected to the light emitting device controller 110 and operate according to a control signal of the light emitting device controller 110.

The plurality of scan lines S ₁ -S _p are scan electrodes of the above-described light emitting device, and the column lines C ₁ -C _q are data electrodes.

The light emitting device controller 110 generates and transmits a scan driver control signal CS that controls the scan driver 114 using the gate control signal CONT1. A column driver control signal CC is generated using the data control signal, and a column signal CLS corresponding to the image signal DAT is generated. The generated column driver control signal CS and the column signal CLS are transmitted to the column driver 112. The light emitting device controller 110 generates luminance information for each pixel of the light emitting device 10 from the image signal DAT of one frame, and generates a column signal CLS according to the generated luminance information.

The scan driver 114 sequentially applies a scan signal having a predetermined pulse to the scan lines S ₁ -S _p based on the received scan driver control signal. The column driver 112 applies a driving voltage corresponding to the color signal to each column line C ₁ -C _q according to the input column driver control signal.

By the above-described configuration, the display unit 116 of the light emitting device 10 receives a driving signal synchronized with the image signal and emits light of an appropriate intensity according to the luminance information for each pixel, which is transmitted to the liquid crystal panel assembly 52. to provide. Each of the light emitting pixels EPX of the light emitting device display unit 116 is preferably driven to display gray scales of 2 to 8 bits.

As a result, when the liquid crystal panel assembly 52 displays a screen having different brightness for each position, the light emitting device 10 provides strong light to the pixel group of the liquid crystal panel assembly 52 displaying a bright portion, Weak light may be provided to the pixel group of the liquid crystal panel assembly 52 to be displayed. In addition, the light emitting pixels of the light emitting device 10 corresponding to the pixel group of the liquid crystal panel assembly 52 displaying black may be turned off.

As a result, the liquid crystal display 50 of the present exemplary embodiment may improve the dynamic contrast of the screen through the above-described process.

In addition, the liquid crystal display device 50 according to the present embodiment uses a light emitting device 10 having the above-described configuration as a backlight unit, and accordingly, a conventional cold cathode fluorescent lamp (hereinafter referred to as 'CCFL') type and a light emitting diode Compared to the backlight unit of the 'LED' method, the following advantages are obtained.

Since the light emitting device 10 of the present embodiment is a surface light source, it does not require a plurality of optical members used in the CCFL type backlight unit and the LED type backlight unit. Therefore, in the light emitting device 10 of the present embodiment, almost no light loss occurs while passing through the optical member, and the light emitting device 10 does not have to emit light of excessive intensity in consideration of the light loss, thereby achieving excellent efficiency with low power consumption. You can get it.

In addition, the light emitting device 10 of the present embodiment has a lower power consumption than the CCFL type backlight unit, and can reduce the cost by not using the optical member. Is low. In addition, since the light emitting device 10 of the present exemplary embodiment is easily enlarged, the light emitting device 10 may be easily applied to a large liquid crystal display of 30 inches or more.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the range of.

The light emitting device according to the present invention can facilitate the cooling of the light emitting device by disposing the light emitting unit having a large amount of heat generated on the rear substrate. Therefore, damage to the light emitting device due to heat generation and thermal deformation of the liquid crystal panel assembly can be suppressed, and the light emitting efficiency of the fluorescent layer can be increased by reducing the temperature of the fluorescent layer during driving, and the fluorescent layer deterioration can be suppressed.

In addition, the liquid crystal display according to the present invention using the above-described light emitting device as a backlight unit can improve the display quality by increasing the dynamic contrast ratio of the screen, and reduce the total power consumption by reducing the power consumption of the backlight unit. It can be easily manufactured with a large display device of inches or more.

Claims (13)

delete delete delete delete delete delete delete delete delete A liquid crystal panel assembly forming a plurality of pixels along the row direction and the column direction; And A light emitting device positioned behind the liquid crystal panel assembly and providing light to the liquid crystal panel assembly Including; The light emitting device, A front substrate and a rear substrate which are disposed opposite to each other and constitute a vacuum container; First electrodes formed on one surface of the front substrate and including a transparent conductive film and an opaque auxiliary electrode formed on a surface of the transparent conductive film and formed of a metal; An opaque material is formed along a direction crossing the first electrodes on the first electrodes with an insulating layer formed of a transparent insulating material therebetween, and is formed on a surface of the transparent conductive film and the transparent conductive film. Second electrodes including an auxiliary electrode; Electron emission parts electrically connected to any one of the first electrodes and the second electrodes; A light reflection film formed on one surface of the rear substrate; And A fluorescent layer formed on the light reflecting film Including; A liquid crystal in which the light emitting device forms fewer pixels than the liquid crystal panel assembly in the row direction and the column direction, and each pixel of the light emitting device independently emits light corresponding to the gray levels of the corresponding liquid crystal panel assembly pixels Display. delete The method of claim 10, The liquid crystal panel assembly forms M pixels along the row direction and N pixels along the column direction, And M and N are each an integer of 240 or more. The method of claim 12, The light emitting device forms M 'pixels along the row direction and N' pixels along the column direction, And M 'and N' are each an integer of 2 to 99.

Images