KR100749424B1 - Light emission device and liquid crystal display with the light emission device as backlight unit - Google Patents

Abstract

A light emission device and a liquid crystal display with a light emission device as a backlight unit are provided to obtain uniform luminance by forming an electron beam diffusion part of low height around an electron emission unit. A vacuum vessel is formed with a first substrate(12), a second substrate, and a sealing member. A plurality of first electrodes(22) are formed along a cross direction on the first substrate. A plurality of second electrodes(26) are formed across the first electrodes. An insulating layer(24) is formed between the first electrodes and the second electrodes. A plurality of electron emission units(28) are formed on the first electrodes in an opening(261) which is formed at the second electrodes and the insulating layer. A phosphor layer is formed on one side of the second substrate. An anode electrode is formed on one side of the phosphor layer. The second electrode includes a main electrode part for maintaining a first height(h1) from the first electrode in an intersectional area with the first electrode, and an electron beam diffusion part for maintaining a second height(h2) from the second height from the first electrode. A light emission device satisfies the following condition t<h2<=2t where h2 is the second height and t is the thickness of the electron emission unit.

Description

LIGHT EMISSION DEVICE AND LIQUID CRYSTAL DISPLAY WITH THE LIGHT EMISSION DEVICE AS BACKLIGHT UNIT}

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

2 is a partially exploded perspective view illustrating an effective area of a light emitting device according to an embodiment of the present invention.

3 is a partially enlarged view of FIG. 2.

4 is an enlarged cross-sectional view partially showing an electron emission unit in the field emission backlight unit according to the related art.

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 feature of changing the amount of light transmission for each pixel by using dielectric anisotropy of a liquid crystal whose twist angle changes according to an applied voltage.

Such a liquid crystal display basically includes a liquid crystal panel assembly and a backlight unit that provides light to the liquid crystal panel assembly, and the liquid crystal panel assembly receives light emitted from the backlight unit and transmits or blocks the light by the action of the liquid crystal layer. By implementing a predetermined image.

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

However, in the CCFL method, since the light generated by the CCFL passes through a plurality of optical members, considerable light loss occurs, and power consumption is high because the light must be emitted at a high intensity 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 constitute a backlight unit by being combined with optical members such as a reflective sheet, a light guide plate, a diffusion sheet, a diffusion plate, and a prism sheet. 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 an electron emission characteristic by an electric field has been proposed as a backlight unit to replace the CCFL method and the LED method. The field emission type backlight unit is a surface light source that has low power consumption, is advantageous for large size, and does not require a plurality of optical members.

In spite of the above advantages, in the conventional field emission type backlight unit, when the electrons are emitted from the electron emission part to emit the fluorescent layer, the initial divergence angle of the electron beam is not large, so only the region corresponding to the electron emission parts of the fluorescent layer is high. A phenomenon of emitting light with luminance is shown. Therefore, the conventional field emission type backlight unit has a disadvantage in that luminance uniformity is reduced because the entire emission surface does not emit light with uniform luminance.

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 light emitting surface emits light with a constant brightness when driving the liquid crystal display.

For example, when the liquid crystal panel assembly displays an arbitrary screen including a high brightness portion and a low brightness portion according to an image signal, the backlight unit provides light of different intensities to the high brightness portion and the low brightness portion. If so, it is possible to realize 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 expand an initial divergence angle of an electron beam to increase luminance uniformity of a light emitting surface, and a liquid crystal display using the light emitting device as a backlight unit. To provide.

Another object of the present invention is to provide a light emitting device capable of dividing a light emitting surface 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 a 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,

A vacuum container composed of a first substrate, a second substrate, and a sealing member, first electrodes formed in one direction of the first substrate on the first substrate, and an insulating layer interposed therebetween. Second electrodes formed along the direction crossing the first electrode, electron emission parts formed on the first electrodes inside the openings formed in the second electrode and the insulating layer, and a fluorescent layer formed on one surface of the second substrate. And a main electrode portion including an anode electrode located on one surface of the fluorescent layer, the second electrode maintaining a first height h1 from the first electrode at an intersection region with the first electrode, and respective electron emission. A light emitting device including an electron beam diffusion part positioned to surround the part and maintaining a second height h2 lower than the first height h1 from the first electrode is provided.

Here, t represents the thickness of an electron emission part.

The main electrode portion and the electron beam diffusion portion may be connected through an inclined portion in which the height of the first electrode gradually decreases from the main electrode portion toward the electron beam diffusion portion.

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

The first substrate and the second substrate are positioned at intervals of 5 to 20 mm, and the light emitting device may further include an anode voltage applying unit configured to apply an anode voltage of 10 to 15 kV to the anode electrode.

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

A liquid crystal panel assembly for forming a plurality of pixels in a row direction and a column direction, and a backlight unit for providing light to the liquid crystal panel assembly and forming a smaller number of pixels in the row direction and the column direction than the liquid crystal panel assembly, A vacuum container including a first substrate, a second substrate, and a sealing member, first electrodes formed along one direction of the first substrate on the first substrate, and first electrodes with an insulating layer interposed therebetween Second electrodes formed along a direction intersecting the first electrode at an upper portion, electron emission parts formed on the first electrodes inside an opening formed in the second electrode and the insulating layer, and formed on one surface of the second substrate A main electrode portion including a fluorescent layer, and an anode electrode positioned on one surface of the fluorescent layer, wherein the second electrode maintains a first height h1 from the first electrode in a region crossing the first electrode; I'm Position so as to surround it with respect to the emitting region, and provides a liquid crystal display device satisfying the beam spread to, and including a condition of maintaining the low second height (h2) than the first height (h1) from the first electrode.

Here, t represents the thickness of an electron emission part.

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

1 is a partial cross-sectional view of a light emitting device according to an embodiment of the present invention, and FIG. 2 is a partially exploded perspective view showing an effective area of a light emitting device according to an embodiment of the present invention.

1 and 2, the light emitting device 10 according to the present exemplary embodiment includes a first substrate 12 and a second substrate 14 that are disposed to face each other in parallel at predetermined intervals. Sealing members 16 are disposed on the edges of the first substrate 12 and the second substrate 14 to bond the two substrates, and the inner space is evacuated with a vacuum of approximately 10 ⁻⁶ Torr so that the first substrate 12 The second substrate 14 and the sealing member 16 constitute a vacuum container.

The first substrate 12 and the second substrate 14 may be divided into an effective region contributing to the actual visible light emission and an ineffective region surrounding the effective region. The effective area of the first substrate 12 is provided with an electron emission unit 16 for electron emission, and the effective area of the second substrate 14 is provided with a light emission unit 18 for visible light emission.

The electron emission unit 18 includes first electrodes 22 formed in a stripe pattern along one direction of the first substrate 12 and the first electrodes 22 with an insulating layer 24 interposed therebetween. Second electrodes 26 are formed in a stripe pattern along a direction crossing the first electrode 22 from the upper portion, and electron emission parts 28 electrically connected to the first electrodes 22.

The first electrode 22 becomes a cathode electrode for supplying current to the electron emission section 28, and the second electrode 26 forms an electric field around the electron emission section 28 due to the voltage difference from the cathode electrode. It becomes a gate electrode which induces electron emission.

Among the first electrode 22 and the second electrode 26, an electrode mainly located along the row direction of the light emitting device 10 functions as a scan electrode, and an electrode located along the column direction of the light emitting device 10 is data. Function as an electrode. In the drawing, the first electrodes 22 are positioned along the column direction (y-axis direction in the drawing) of the light emitting device 10, and the second electrodes 26 are positioned in the row direction (x-axis of the drawing) of the light emitting device 10. Direction) is shown.

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

The electron emission unit 28 may be formed of materials emitting electrons when an electric field is applied, such as a carbon-based material or a nanometer-sized material. The electron emission unit 28 may include, for example, a material selected from the group consisting of carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, fullerenes (C ₆₀ ), silicon nanowires, and combinations thereof. Screen printing, direct growth, chemical vapor deposition or sputtering may be applied to the preparation method.

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 area of the first electrode 22 and the second electrode 26 corresponds to one pixel area of the light emitting device 10, or two or more crossing areas are one pixel area of the light emitting device 10. It can correspond to. In the second case, two or more first electrodes 22 and / or two or more second electrodes 26 positioned in one pixel area are electrically connected to each other to receive the same driving voltage.

3 is a partially enlarged view of FIG. 2.

1 to 3, in the present exemplary embodiment, the second electrode 26 maintains a first height h1 from the first electrode 22 in a region crossing the first electrode 22. 261 and an electron beam diffuser 262 positioned to surround each electron emitter 28 and maintaining a second height h2 smaller than the first height h1 from the first electrode 22. )

For the above-described configuration, the insulating layer 24 is formed to have a thickness of h1 under the main electrode portion 261 and a thickness of h2 under the electron beam diffusion portion 262. In addition, the main electrode portion 261 and the electron beam diffusion portion 262 of the second electrode 26 gradually decrease the height of the first electrode 22 from the main electrode portion 261 toward the electron beam diffusion portion 262. Can be connected via the inclined portion 263 to.

At this time, the height h2 of the electron beam diffusion part 262 with respect to the first electrode 22 is formed to satisfy the following condition.

Here, t represents the thickness of the electron emission part 28.

As the second electrode 26 forms the electron beam diffuser 262 that satisfies the above-described mathematical condition around the electron emitter 28, the first electrode 22 and the second electrode 26, in particular, When an electric field is formed around the electron emitter 28 due to the voltage difference between the first electrode 22 and the electron beam diffuser 262, and electrons are emitted therefrom, the height of the electron beam diffuser 262 is reduced. Initial divergence angle is enlarged.

In the above equation, when the height h2 of the electron beam diffusion part 262 with respect to the first electrode 22 is smaller than the thickness t of the electron emission part 28, the second electrode 26 turns on / off the electron emission. If the height h2 of the electron beam diffusion portion 262 with respect to the first electrode 22 exceeds 2 times the thickness t of the electron emission portion 28, it is large to enlarge the initial divergence angle of the electron beam. It becomes difficult to achieve the effect.

Next, the light emitting unit 20 includes a fluorescent layer 30 and an anode electrode 32 positioned on one surface of the fluorescent layer 30.

The fluorescent layer 30 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 in the entire effective area of the second substrate 14 or may be divided and positioned in a predetermined pattern so that one white fluorescent layer is positioned in each pixel area. The red, green, and blue fluorescent layers are divided and positioned in a predetermined pattern in one pixel area. In the drawing, a case where the white fluorescent layer is positioned in the entire effective region of the second substrate 14 is illustrated.

The anode electrode 32 may be formed of a metal film such as aluminum covering the surface of the fluorescent layer 30. The anode electrode 32 is an acceleration electrode for attracting an electron beam to maintain the fluorescent layer 30 in a high potential state by applying a high voltage and radiate toward the first substrate 12 of visible light emitted from the fluorescent layer 30. Visible light is reflected toward the second substrate 14 to increase the luminance of the light emitting surface.

In addition, spacers (not shown) are disposed between the first substrate 12 and the second substrate 14 to support the compressive force applied to the vacuum container and to keep the distance between the two substrates constant.

The light emitting device 10 having the above-described configuration applies a predetermined driving voltage to the first electrodes 22 and the second electrodes 26 from the outside of the vacuum container, and the direct current amount of thousands of volts or more to the anode electrode 32. Drive by applying voltage.

Then, in the pixels where the voltage difference between the first electrode 22 and the second electrode 26 is greater than or equal to the threshold, an electric field is formed around the electron emission unit 28 to emit electrons therefrom, and the emitted electrons are attracted to the anode voltage to correspond. It emits light by colliding with a portion of the fluorescent layer 30. The emission intensity of the fluorescent layer 30 for each pixel corresponds to the electron beam emission amount of the corresponding pixel.

In the above-described driving process, the light emitting device 10 according to the present embodiment enlarges the initial divergence angle of the electrons by forming the electron beam diffusion part 262 around the electron emission part 28, and as a result, uniform luminance of the entire emission surface. By emitting light, the luminance uniformity of the light emitting surface can be increased.

4 is an enlarged cross-sectional view partially showing an electron emission unit in the field emission backlight unit according to the related art.

Referring to FIG. 4, in the field emission type backlight unit of the comparative example, the insulating layer 11 is formed to have a uniform thickness over the entire first substrate 13, and the second electrode 15 is also formed from the first electrode 17. Keep it at a uniform height. In this structure, even when the size of the second electrode opening 151 is the same as that of the light emitting device of this embodiment, the height of the second electrode 15 with respect to the electron emitting portion 19 is larger than that of the light emitting device of this embodiment. It can be seen that the divergence angle is small.

Meanwhile, in the above-described embodiment, the first substrate 12 and the second substrate 14 may be positioned at a larger interval, for example, 5 to 20 mm, than the conventional field emission backlight unit. The anode electrode 32 may be provided with a high voltage of about 10 kV or more, preferably about 10 to 15 kV, through an anode voltage applying unit (not shown). The light emitting device 10 according to the present exemplary embodiment may implement a maximum luminance of about 10,000 cd / m ² or more in the center of the effective region through the above-described configuration.

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 40 according to the present exemplary embodiment includes a liquid crystal panel assembly 42 having arbitrary pixels in a row direction and a column direction, and is positioned behind the liquid crystal panel assembly 42 to provide a liquid crystal panel assembly ( 42 to a light emitting device 10 that provides light. Hereinafter, for convenience, the light emitting device 10 will be referred to as a 'backlight unit'. As the liquid crystal panel assembly 42, all known liquid crystal panel assemblies may be applied.

The backlight unit 10 may implement uniform luminance on the entire light emitting surface by the above-described second electrode shape. Therefore, an optical member such as a diffusion plate or a diffusion sheet may be omitted between the liquid crystal panel assembly 42 and the backlight unit 10, and the configuration of the liquid crystal display 40 may be simplified.

The row direction may be defined as one direction of the liquid crystal display 40, for example, a horizontal direction (x-axis direction in the drawing) of the screen implemented by the liquid crystal panel assembly 42, and the column direction may be defined as the liquid crystal display 40. ) May be defined as a vertical direction (y-axis direction of the drawing) of the screen implemented by the liquid crystal panel assembly 42.

In the present exemplary embodiment, the backlight unit 10 forms a smaller number of pixels than the liquid crystal panel assembly 42 along the row direction and the column direction so that one pixel of the backlight unit 10 has two or more liquid crystal panel assemblies 42. To correspond to the pixels.

When the number of pixels of the liquid crystal panel assembly 42 in the row direction and the number of pixels of the liquid crystal panel assembly 42 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 backlight unit 10 in the row direction and the number of pixels of the backlight unit 10 in the column direction are M 'and N', respectively, M 'and N' are any integer of 2 to 99. Can be defined as

The backlight unit 10 is a kind of self-luminous display panel having a resolution of M '× N', and the light emission intensity is independently controlled for each pixel to provide light of appropriate intensity to the liquid crystal panel assembly pixels corresponding to each pixel.

In this case, 2, which is the minimum value of M 'and N', is the minimum basic condition that the backlight unit 10 of the present exemplary embodiment may be the display panel. In addition, if the resolution of the backlight unit 10 exceeds 99 × 99, the driving of the backlight unit may be complicated and a cost increase for manufacturing a driving circuit may be caused. Therefore, 99, which is the maximum value of M 'and N', is the backlight unit 10. It can be said that the value considering the functionality and ease of manufacture.

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

Referring to FIG. 6, the driving unit of the liquid crystal display includes a first scan driver 102 and a first data driver 104 connected to the liquid crystal panel assembly 42, and a gray voltage generator connected to the first data driver 104. 106, a second scan driver 114 and a second data driver 112 connected to the display unit 116 of the backlight unit 10, a backlight unit controller 110 that controls the backlight unit 10, and And a signal controller 108 including a backlight unit controller 110 and controlling the liquid crystal panel assembly 42.

The liquid crystal panel assembly 42 includes a plurality of signal lines S ₁ -S _n , D ₁ -D _m , and a plurality of first pixels PX connected to the signal lines and arranged in an approximately matrix form in an equivalent circuit. It includes. The signal lines S ₁ -S _n and D ₁ -D _m are a plurality of first scan lines S ₁ -S _n which transmit a first scan signal, and a plurality of first data lines which transfer a first data signal. (D ₁ -D _m ).

Each of the pixels (PX), for instance the i-th (i = 1,2, ... n) first scan line (S _i) and the j-th (j = 1,2, ... m) the first data line the pixel 44 is connected to the (D _j) comprises a switching element (Q) and the liquid crystal capacitors (Clc) and a storage capacitor (Cst) connected thereto is connected to the signal line (S _i, D _j). Holding capacitor Cst can be omitted as needed.

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

The first scan driver 102 applies a first scan signal, which is a combination of a switch-on voltage Von and a switch-off voltage Voff, to the first scan lines S ₁ -S _n . The first data driver 104 selects a gray voltage from the gray voltage generator 106 and applies the gray voltage to the first data line D ₁ -D _m as a data signal.

The signal controller 108 controls the first scan driver 102 and the first data driver 104, and the backlight unit controller 110 controls the second scan driver 114 and the second data driver of the backlight unit 10. Control 112. 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 first pixel PX, and the luminance is a predetermined number, for example, 1024 (= 2 ¹⁰ ), 256 (= 2 ⁸ ), or It has 64 (= 2 ⁶ ) 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 properly processes the input image signals R, G, and B based on the input image signals R, G, and B and the input control signal, according to operating conditions of the liquid crystal panel assembly 42. After generating the scan driver control signal CONT1 and the first data driver control signal CONT2, etc., the first scan driver control signal CONT1 is sent to the first scan driver 102, and the first data driver control signal ( CONT2) and the processed video signal DAT are sent to the first data driver 104.

The display unit 116 of the backlight unit 10 includes a plurality of second pixels EPX, and each of the second pixels EPX includes one second scan line S ′ ₁ -S ′ _p and one agent. 2 is connected to the data lines C ₁ -C _q . Each second pixel EPX emits light according to a voltage difference applied to the second scan line S ′ ₁ -S ′ _p and the second data line C ₁ -C _q .

The signal controller 108 uses the input image signals R, G, and B for the plurality of first pixels PX corresponding to one second pixel EPX of the backlight unit 10, and the backlight unit 10. Generates a light emission control signal. The emission control signal includes a second data driver control signal CD, an emission signal CLS, and a second scan driver control signal CS. According to the second data driver control signal CD, the light emission signal CLS, and the second scan driver control signal CS, each of the second pixels EPX of the backlight unit 10 includes a plurality of first pixels PX. In response to the light emission.

In detail, the signal controller 108 may receive an input image signal corresponding to a plurality of first pixels PX (hereinafter, referred to as a “first pixel group”) corresponding to one second pixel EPX of the backlight unit. The highest gray level among the first pixels PX of the first pixel group is detected using R, G, and B, and transmitted to the backlight unit controller 110. The backlight unit controller 110 calculates the grayscale required to emit the second pixel EPX according to the detected grayscale, converts the grayscale to digital data, and transmits the grayscale to the second data driver 112.

In the present exemplary embodiment, the light emission signal CLS includes 6-bit or more digital data for gray scale representation of the second pixel EPX. The second data driver control signal CD allows each second pixel EPX to emit light in synchronization with the first pixel group corresponding to the second pixel EPX. That is, the second pixel EPX is synchronized to emit light with a predetermined gray scale in accordance with the display of the image in the first pixel group corresponding to one second pixel EPX.

The second data driver 112 generates a second data signal according to the second data driver control signal CD and the light emission signal CLS and applies the second data signal to each second data line C ₁ -C _q .

In addition, the backlight unit controller 110 generates the second scan driver control signal CS of the backlight unit 10 using the horizontal synchronization signal Hsync. The second scan driver 114 generates a second scan signal according to the second scan driver control signal CS, and transmits the second scan signal to the second scan lines S ′ ₁ -S ′ _p . While the switch-on voltage Von is applied to the first pixel group corresponding to the second pixel EPX of the backlight unit 10, the second scan line S ′ ₁ -S 'of the second pixel EPX. _p ) is applied with a second scan signal.

Then, the second pixel EPX emits light corresponding to the gray level of the corresponding first pixel group by the second scan voltage and the second data voltage. In the present embodiment, a voltage according to the gray level is applied to the second data lines C ₁ -C _q of the second pixel EPX, and a constant amount of voltage is applied to the second scan lines S ′ ₁ -S ′ _p . The second pixel EPX emits light due to a voltage difference between two lines.

The liquid crystal display 40 according to the present exemplary embodiment may improve the dynamic contrast of the screen through the above-described process, and may implement more clear image quality.

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 forms an electron beam diffusion portion having a lower height around the electron emission portion, thereby expanding the initial divergence angle of the electron beam, thereby emitting the entire fluorescent layer with uniform luminance. Therefore, the light emitting device according to the present invention can increase the luminance uniformity of the light emitting surface.

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 can reduce the overall power consumption by reducing the power consumption of the backlight unit, 30 inches or more It can be easily manufactured in a large display device.

Claims (9)

A vacuum container composed of a first substrate, a second substrate, and a sealing member; First electrodes formed on the first substrate in one direction of the first substrate; Second electrodes formed along the direction crossing the first electrode on the first electrodes with an insulating layer interposed therebetween; Electron emission parts formed on the first electrodes inside the openings formed in the second electrodes and the insulating layer; A fluorescent layer formed on one surface of the second substrate; And An anode located on one surface of the fluorescent layer, A main electrode portion having a first height h1 from the first electrode at an intersection region with the first electrode, and positioned so as to surround the respective electron emission portions, A light emitting device comprising an electron beam diffusion portion for maintaining a second height h2 lower than one height h1, and satisfying the following conditions.

Here, t represents the thickness of an electron emission part. The method of claim 1, And the main electrode portion and the electron beam diffusion portion are connected through an inclined portion in which the height of the first electrode gradually decreases from the main electrode portion toward the electron beam diffusion portion. The method of claim 1, The light emitting device of claim 1, wherein the electron emission unit comprises at least one of a carbon-based material and a nanometer-sized material. The method according to any one of claims 1 to 3, The first substrate and the second substrate are positioned at intervals of 5 to 20 mm, And an anode voltage applying unit configured to apply an anode voltage of 10 to 15 kV to the anode electrode. A liquid crystal panel assembly forming a plurality of pixels along the row direction and the column direction; And A backlight unit providing light to the liquid crystal panel assembly and forming a smaller number of pixels in the row direction and the column direction than the liquid crystal panel assembly, The backlight unit, A vacuum container composed of a first substrate, a second substrate, and a sealing member; First electrodes formed along one direction of the first substrate on the first substrate, second electrodes formed along an intersecting direction with the first electrode on the first electrodes with an insulating layer interposed therebetween; An electron emission unit including electron emission parts formed on the first electrodes inside the openings formed in the second electrode and the insulating layer; And A light emitting unit including a fluorescent layer formed on one surface of the second substrate and an anode electrode located on one surface of the fluorescent layer, A main electrode portion having a first height h1 from the first electrode at an intersection region with the first electrode, and positioned so as to surround the respective electron emission portions, A liquid crystal display device comprising an electron beam diffusion portion for maintaining a second height h2 lower than one height h1, and satisfying the following conditions.

Here, t represents the thickness of an electron emission part. The method of claim 5, And a number of pixels of the backlight unit in the row direction and a number of pixels of the backlight unit in the column direction is any one of 2 to 99. The method of claim 5, And the main electrode portion and the electron beam diffusion portion are connected through an inclined portion in which the height of the first electrode gradually decreases from the main electrode portion toward the electron beam diffusion portion. The method of claim 5, And the electron emitter comprises at least one of a carbon-based material and a nanometer-sized material. The method according to any one of claims 5 to 8, The first substrate and the second substrate are positioned at intervals of 5 to 20 mm, The backlight unit further comprises an anode voltage applying unit for applying an anode voltage of 10 to 15kV to the anode electrode.

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