KR100717762B1 - Light emitting device and liquid crystal display with the light emitting device as backlight unit - Google Patents

Abstract

The present invention provides a light emitting device that emits light using field emission characteristics and a liquid crystal display using the light emitting device as a backlight unit. The light emitting device according to the present invention includes a vacuum container including a first substrate, a second substrate, and a sealing member, and first and second electrodes formed along a direction crossing each other while maintaining insulation on the first substrate. And electron emission parts electrically connected to the first electrodes. Each of the first electrodes includes a voltage applying part located at one edge of the first substrate, a first line part extending from the voltage applying part toward the opposite edge of the first substrate, and parallel to the first line part. A first line portion region and a second line portion region, which include a second line portion extending from the line portion toward the voltage applying portion, intersect with one second electrode, form one pixel.

Electron emission part, cathode electrode, gate electrode, insulating layer, fluorescent layer, anode electrode, voltage drop

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 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 cutaway perspective view illustrating an effective area of a light emitting device according to an exemplary embodiment of the present invention.

3 is a partial plan view of an electron emission unit of a light emitting device according to an embodiment of the present invention.

4 is a plan view schematically illustrating a first substrate and first electrodes of a light emitting device according to an exemplary embodiment of the present invention.

5 is a plan view illustrating a first electrode of a light emitting device according to a second exemplary embodiment of the present invention.

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

7 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, has the advantage of low power consumption, large size, and does not require a complicated optical member.

In spite of the above advantages, since the voltage drop occurs due to the internal resistance of the stripe type electrode in the conventional field emission type backlight unit, the amount of emission current is nonuniform along the length direction of the electrode. Therefore, the conventional field emission type backlight unit has a disadvantage in that the luminance is changed along the longitudinal direction of the electrode and thus the luminance uniformity is reduced in the entire light emitting surface.

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 in that it is difficult to meet the image quality improvement required for the liquid crystal display device since the entire light emitting surface is driven to display a constant luminance when the liquid crystal display device is driven.

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 provide a light emitting device capable of improving the luminance uniformity of a light emitting surface and a liquid crystal display using the light emitting device as a backlight unit.

It is another object of the present invention to divide a light emitting surface into a plurality of regions and to emit light of different intensities for each divided region, and a liquid crystal capable of increasing the dynamic contrast ratio of a screen by using the light emitting apparatus as a backlight unit. It is to provide a display 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 and second electrodes formed along a direction intersecting with each other while maintaining insulation on the first substrate; Electron emission parts electrically connected to each other, a fluorescent layer formed on one surface of the second substrate, and an anode electrode located on one surface of the fluorescent layer, wherein each of the first electrodes is positioned at one edge of the first substrate. An application portion, a first line portion extending from the voltage application portion toward the opposite edge of the first substrate, and a second line portion parallel to the first line portion and extending from the first line portion toward the voltage application portion, Provided is a light emitting device in which a first line portion region and a second line portion region intersecting one second electrode form one pixel.

The first electrode may further include a third line portion extending from the second line portion toward the opposite edge of the first substrate.

The second electrodes may be positioned above the first electrodes with an insulating layer interposed therebetween, wherein the second electrodes and the insulating layer form openings at intersections of the first electrodes and the second electrodes, respectively. The electron emission part may be positioned on the first electrode inward.

The electron emission part includes at least one of a carbonaceous material and a nanometer size material.

The first substrate and the second 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 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 comprising a liquid crystal panel assembly for forming a plurality of pixels along the row direction and a column direction, and a light emitting device 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 Provide a display device. The light emitting device includes a vacuum container including a first substrate, a second substrate, and a sealing member, first and second electrodes formed along a direction intersecting each other while maintaining insulation on the first substrate; Electron emission parts electrically connected to the first electrodes, a fluorescent layer formed on one surface of the second substrate, and an anode electrode located on one surface of the fluorescent layer. Each of the first electrodes includes a voltage applying part positioned at one edge of the first substrate, a first line part extending from the voltage applying part toward the opposite edge of the first substrate, and parallel to the first line part. A first line portion region and a second line portion region, which include a second line portion extending from the first line portion toward the voltage applying portion, intersect one second electrode, form one pixel. The light emitting device emits light of different intensity for each pixel by the first electrodes and the second electrodes.

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 partial cutaway 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 internal space is evacuated to a vacuum of approximately 10 ⁻⁶ Torr to form the first substrate 12. And 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 18 for electron emission, and the effective area of the second substrate 14 is provided with a light emission unit 20 for visible light emission.

The electron emission unit 18 may be formed on the first electrodes 22 formed in a stripe pattern along one direction of the first substrate 12 and on the first electrodes 22 with the insulating layer 24 therebetween. Electrons electrically connected to the second electrodes 26 formed in a stripe pattern along a direction crossing the first electrode 22 and to any one of the first electrodes 22 and the second electrodes 26. Discharge portions 28.

When the electron emission portion 28 is formed on the first electrode 22, the first electrode 22 becomes a cathode electrode for supplying current to the electron emission portion 28, and the second electrode 26 is a cathode electrode. An electric field is formed by the voltage difference between and the gate electrode is used to induce electron emission. On the contrary, when the electron emission part 28 is formed in the 2nd electrode 26, the 2nd electrode 26 will be a cathode and the 1st electrode 22 will be a gate electrode.

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 provided. It functions as a data electrode.

In the drawing, the electron emission unit 28 is formed on the first electrode 22, 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 electrode The case where the fields 26 are located along the row direction (x-axis direction of the figure) of the light emitting device 10 is shown. The position of the electron emitter 28 and the arrangement directions of the first electrodes 22 and the second electrodes 26 are not limited to the above-described example and may be variously modified.

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

3 is a partial plan view of an electron emission unit of a light emitting device according to an exemplary embodiment of the present invention, and FIG. 4 is a plan view schematically showing a first substrate and first electrodes.

Referring to FIGS. 3 and 4, in this embodiment, the first electrodes 22, which contact the electron emitters 28 and function as cathodes, are moved out of the vacuum vessel at one edge of the first substrate 12. Parallel to the exposed voltage applying unit 221, the first line unit 222 extending from the voltage applying unit 221 toward the opposite side edge of the first substrate 12, and the first line unit 222. And a second line part 223 extending from the first line part 222 toward the voltage applying part 221.

The driving voltage applied to the voltage applying unit 221 is transmitted to the second line unit 223 via the first line unit 222 and along the length direction (x-axis direction of the drawing) of the second electrode 26. A portion of the first line portion 222 and a portion of the second line portion 223 positioned side by side together with the second electrode 26 form one pixel area. In FIG. 4, the pixel area where the first electrode 22 and the second electrode 26 cross each other is illustrated by a broken line.

In the structure of the first electrode 22, the voltage drop occurs as the distance from the voltage applying unit 221 increases. In the region close to the voltage applying unit 221, the voltage and the first line part 222 having the lowest voltage drop are the lowest. The second line part 223 having the largest dropping degree forms one pixel, and the first line part 222 and the second line part having the intermediate voltage drop in the region far from the voltage applying part 221. 223 forms one pixel.

Therefore, in the above-described structure of the first electrode 22, the amount of emission current in all pixels positioned along the length direction (y-axis direction of the drawing) of the first electrode 22 regardless of the distance from the voltage applying unit 221. The same effect can be obtained.

1 and 2, the light emitting unit 20 includes a fluorescent layer 30 and an anode electrode 32 disposed 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 a direct current amount of thousands of volts 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. It hits the fluorescent layer 30 to emit light. 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 exemplary embodiment includes a first line part 222 and a second line part 223, and the first line part 222 and the first line part 222. As one pixel is formed by the second line unit 223, the luminance may be uniformly emitted on the emission surface in the pixels positioned along the length direction of the first electrode 22 to achieve uniform luminance.

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 a plan view illustrating a first electrode of a light emitting device according to a second exemplary embodiment of the present invention.

Referring to FIG. 5, in the present exemplary embodiment, the first electrode 22 ′ may have a voltage applying unit 221 formed at one edge of the first substrate and an edge of the opposite side of the first substrate from the voltage applying unit 221. A first line portion 222 extending toward the second line portion 222 parallel to the first line portion 222 and extending from the first line portion 222 toward the voltage applying portion 221; The third line part 224 is formed in parallel with the second line part 223 and extends from the second line part 223 toward the opposite side edge of the first substrate.

The driving voltage applied to the voltage applying unit 221 is transmitted to the third line unit 224 via the first line unit 222 and the second line unit 223, and the length of the second electrode (not shown). A portion of the first line portion 222, a portion of the second line portion 223, and a portion of the third line portion 224 positioned side by side along the direction (the x-axis direction of the drawing) may be disposed together with the second electrode. In the figure).

In the above-described structure of the first electrode 22 ', the voltages of the first line part 222, the second line part 223, and the third line part 224, which have different degrees of voltage drop, form one pixel. Irrespective of the distance from the applying unit 221, the amount of emission current can be obtained in all pixels positioned along the length direction (y-axis direction of the drawing) of the first electrode 22 '.

6 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. 6, 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 form a liquid crystal panel assembly ( 42 to a light emitting device 10 that provides light. Any known liquid crystal panel assembly may be applied to the liquid crystal panel assembly 42, 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 42 and the light emitting device 10 as necessary.

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 particular, in the present embodiment, the light emitting device 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 light emitting device 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 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

The light emitting device 10 is a self-emission 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 corresponding liquid crystal panel assembly 42 pixels. In this case, 2, which is the minimum value of M 'and N', is a minimum condition for the light emitting device 10 to form a self-luminous display panel, and when M 'and N' are greater than 99, the pixel of the light emitting device 10 Excessive numbers may make manufacturing and driving of the light emitting device 10 difficult, resulting in an increase in manufacturing cost.

7 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. 7, the liquid crystal display of the present exemplary embodiment includes a liquid crystal panel assembly 42, a first scan driver 102 and a first data driver 104 connected to the liquid crystal panel assembly 42, and a first data driver. A gray voltage generator 106 connected to the 104, a light emitting device 10, and a signal controller 108 for controlling the gray voltage generator 106 are included.

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 may include a plurality of first gate lines S ₁ -S _n transmitting a first scan signal and a plurality of first data lines transferring 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.

A switching element (Q) is a three-terminal element such as thin film transistors included in liquid crystal panel assembly 42, a lower substrate (not shown), the control terminal is connected to the first gate line (S _i), the input terminal Is connected to the first data 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 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 is connected to the first scan lines S ₁ -S _n of the liquid crystal panel assembly 42 to form a first scan signal formed by a combination of a switch on voltage Von and a switch off voltage Voff. Is applied to the first scan lines S ₁ -S _n .

The first data driver 104 is connected to the first data lines D ₁ -D _m of the liquid crystal panel assembly 42 and selects a gray voltage from the gray voltage generator 106 and uses the first data as a data signal. Apply to lines D ₁ -D _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 first data driver 104 divides the reference gray voltages to provide total gray levels. A gray voltage is generated and a data signal is selected from among them.

The signal controller 108 controls the first scan driver 102 and the first data driver 104 and includes a light emitting device controller 110 for controlling the light emitting device 10. The light emitting device controller 110 controls the second scan driver 114 and the second data driver 112 of the light emitting device 10. The signal controller receives the input image signals R, G, and 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 light emitting device 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 second scan lines S ′ ₁ -S ′ _p correspond to electrodes positioned along the row direction of the light emitting device 10, and the second data lines C ₁ -C _q correspond to the column directions of the light emitting devices. Corresponding to the electrodes positioned along.

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 light emitting device 10 to emit light. 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 light emitting device 10 includes a plurality of first pixels PX. In response to the light emission.

Specifically, the signal controller 108 emits light using the input image signals R, G, and B for the plurality of first pixels PX corresponding to one second pixel EPX of the light emitting device 10. The highest gray level among the plurality of first pixels PX corresponding to one second pixel EPX of the device 10 is detected and transmitted to the light emitting device controller 110. The light emitting device controller 110 calculates a gray level of the second pixel EPX of the light emitting device 10 corresponding to the detected gray level, converts it into digital data, and transmits the gray level to the second data driver 112.

In the present exemplary embodiment, the light emission signal CLS includes 6-bit or more digital data according to the gray level of the second pixel EPX of the light emitting device 10. The second data driver control signal CD allows each second pixel EPX to emit light in synchronization with a plurality of first pixels PX 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 on the plurality of first pixels PX corresponding to one second pixel EPX.

The second data driver 112 is connected to the second data lines C ₁ -C _q , and generates a second data signal based on the second data driver control signal CD and the emission signal CLS. 2 is applied to the data lines C ₁ -C _q .

In addition, the light emitting device controller 110 generates the second scan driver control signal CS of the light emitting device 10 by using the horizontal synchronization signal Hsync. That is, the second scan driver 114 is connected to the second scan line S ′ ₁ -S ′ _p , generates a second scan signal according to the second scan driver control signal CS, and generates a second scan. Pass on lines S ' _1- S' _p . The second of the second pixel EPX of the light emitting device 10 while the switch-on voltage Von is applied to the plurality of first pixels PX corresponding to the second pixel EPX of the light emitting device 10. The second scan signal is applied to the scan lines S ' _1- S' _p .

Then, while the plurality of first pixels PX are displayed, the second pixel EPX is applied to the second scan line S ′ ₁ -S ′ _p and the second scan voltage and the second data line C _1- . According to the second data voltage applied to C _q ), light is emitted corresponding to the gray levels of the plurality of first pixels PX. 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 by a voltage difference between two lines.

Therefore, the liquid crystal display 40 of the present embodiment can improve the dynamic contrast of the screen through the above-described process, and can realize a clearer picture 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 light emitting device according to the present invention can make the emission current uniform in the pixels positioned along the longitudinal direction of the first electrode by the above-described first electrode configuration. Therefore, the light emitting device according to the present invention can increase the luminance uniformity in the entire 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 (10)

A vacuum container composed of a first substrate, a second substrate, and a sealing member; First and second electrodes on the first substrate, the first and second electrodes being insulated from each other and formed in a direction crossing each other; Electron emission parts electrically connected to the first electrodes; A fluorescent layer formed on one surface of the second substrate; And An anode located on one surface of the fluorescent layer, The first electrode is parallel to the first line portion, a voltage applying portion located at one edge of the first substrate, a first line portion extending from the voltage applying portion toward the opposite edge of the first substrate, A second line portion extending from the first line portion toward the voltage applying portion, Wherein the first line portion region and the second line portion region that intersect the one second electrode form one pixel. The method of claim 1, And a third line portion, wherein the first electrode extends from the second line portion toward the opposite edge of the first substrate. The method according to claim 1 or 2, The second electrodes are positioned on the first electrodes with an insulating layer interposed therebetween, The second electrodes and the insulating layer form openings at respective crossing regions of the first electrodes and the second electrodes, And the electron emission part positioned on the first electrode inside the respective openings. 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 of claim 1, 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 light emitting device 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, The light emitting device, A vacuum container composed of a first substrate, a second substrate, and a sealing member; An electron emission unit including first and second electrodes formed on the first substrate, the first and second electrodes being insulated from each other and intersecting with each other, and electron emission parts electrically connected to the first electrodes; 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, The first electrode is parallel to the first line portion, a voltage applying portion located at one edge of the first substrate, a first line portion extending from the voltage applying portion toward the opposite edge of the first substrate, A second line portion extending from the first line portion toward the voltage applying portion, And the first line portion and the second line portion, which cross the one second electrode, form one pixel. The method of claim 6, An integer of 240 or more pixels in the liquid crystal panel assembly in the row direction and the number of pixels in the liquid crystal panel assembly in the column direction. The method according to claim 6 or 7, And a number of pixels of the light emitting device along the row direction and a number of pixels of the light emitting device along the column direction are any one of 2 to 99. The method of claim 6, And a third line portion, wherein the first electrode extends from the second line portion toward the opposite edge of the first substrate. The method of claim 6, And the electron emitter comprises at least one of a carbon-based material and a nanometer-sized material.

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