KR20030080992A - Field emission display device - Google Patents

Abstract

PURPOSE: A field emission display is provided to achieve improved color purity of screen by preventing a neighboring effect, while obtaining a high contrast. CONSTITUTION: A field emission display comprises a front substrate(2) and a rear substrate(4) opposed each other; a gate electrode(6) formed into a line pattern on the rear substrate; an insulating layer(8) formed on the rear substrate in such a manner that the insulating layer covers the gate electrode; a cathode electrode(10) formed on the insulating layer into a line pattern crossing the gate electrode, and which has a through hole(12) formed in each pixel area crossing the gate electrode; a carbon based plane electron source disposed on the cathode electrode adjacent to one side of the through hole; an anode electrode(16) formed on the front substrate opposed to the rear substrate; and a phosphor film(18) formed at the surface of the anode electrode.

Description

Field emission display device {FIELD EMISSION DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field emission display device, and more particularly, to a field emission display device having a plane electron source made of a carbon-based material, a cathode on a rear substrate, and a gate electrode disposed under the plane electron source.

Field emission displays, which use cold cathodes as electron emission sources to implement images, have recently been fabricated by thick film processes such as screen printing using carbon-based materials that emit electrons at low voltage (approximately, 10 to 15 V). Technology for forming an electron source, that is, an emitter, is being researched and developed.

When the field emission display device has a triode structure having a cathode, an anode, and a gate electrode, a known field emission display device sequentially forms a cathode electrode, an insulating layer, and a gate electrode on a rear substrate, and forms a gate electrode. A hole is formed in the insulating layer to expose the cathode, and the emitter is formed on the exposed surface of the cathode and the anode and the fluorescent film are disposed on the front substrate.

However, in the above-described structure, it is technically very difficult to form a plane electron source using a thick film process. This is because when screen-printing a carbon-based material to the surface of the cathode electrode exposed by the hole, the carbon-based material is formed across the cathode electrode and the gate electrode to cause a short between the two electrodes.

Accordingly, the present applicant has proposed a field emission display device in which a gate electrode is arranged under an insulating layer between a cathode electrode and a surface electron source in Korean Laid-Open Patent Publication No. 2001-58675. In the above structure, there is no possibility that the cathode electrode and the gate electrode are short-circuited during the manufacturing process, and there is an advantage that a surface electron source can be easily formed on the cathode electrode.

However, in the above structure, when the distance between the cathode electrodes is more than a certain distance (for example, 1/3 or more of the pitch of the gate electrode), the data voltage applied to the neighboring gate electrode as well as the data voltage applied to the corresponding gate electrode is specified. A neighboring effect phenomenon occurs in which the electric field strength around the surface electron source is changed.

The navering effect phenomenon is based on a specific surface electron source constituting a pixel, and when a data voltage is applied to a gate electrode of a neighboring pixel, the electric field of the pixel is relatively strengthened to increase the emission current, and the gate of the neighboring pixel is increased. If no data voltage is applied to the electrode, it means that the electric field of the pixel is weakened and the emission current decreases.

Therefore, when a data voltage is applied to a specific gate electrode, not only the surface electron source corresponding to the gate electrode but also the surface electron source of the neighboring pixel further emits an electric field. When the screen is bright when displaying a white image on the screen, displaying a specific color causes unbalance in luminance, in which a dark color appears.

The above problem is reduced as the distance between the cathode electrodes is reduced. Experimentally, when the pitch of the gate electrode is 320 μm, the naver effect disappears when the distance between the cathode electrodes is about 20 μm. .

However, if the distance between the cathode electrodes is too close, since the data voltage applied to the gate electrode is blocked by the adjacent cathode electrode does not affect the increase of the electric field of the surface electron source, it is impossible to control the field emission by the gate electrode A problem arises in that the matrix driving becomes impossible.

In addition, the above-described field emission display device forms a surface electron source at one edge of the cathode electrode, and an electric field induced from the gate electrode surrounds the surface electron source to generate a field emission. In general, the cathode electrode has a wide width in consideration of conductivity. As such, the electric field causing the field emission has a strong influence only on the edge of the plane electron source.

Therefore, compared with the conventional triode structure, the structure has a relatively low intensity of the electric field formed around the surface electron source and a narrow field emission region, thereby increasing driving voltage and power consumption required for electron emission. In addition, since the field emission region is narrow, the amount of electron emission is small, and the lifetime of the surface electron source is low.

On the other hand, in the field emission display, the brightness of the screen is proportional to the amount of electron emission and the voltage applied to the anode, and considering the lifespan characteristics of the field emission display, the amount of electron emission per unit area is limited to a certain level or less due to the limitation of the phosphor material. Therefore, when the high voltage is applied to the anode electrode, the brightness characteristic of the screen is improved.

However, in the existing structure in which the surface electron source and the anode electrode face each other over a large area, when a high voltage is applied to the anode electrode, an electric field between the cathode electrode and the anode electrode increases, and the possibility of arcing increases. As a result, a problem arises in that the surface electron source is damaged or deteriorated by arcing, thereby lowering the uniformity of light emission 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 field emission display device which prevents a navering effect phenomenon by blocking an electric field change of each pixel due to a data voltage applied to a gate electrode of a neighboring pixel. To provide.

Another object of the present invention is to provide a field emission display device capable of increasing the amount of electron emission by extending the field emission area to lower the driving voltage of the display device and increasing the intensity of the electric field applied to the surface electron source.

It is still another object of the present invention to provide a field emission display device capable of improving the brightness of a screen by applying a high voltage to the anode electrode while reducing the possibility of arcing occurring between the cathode electrode and the anode electrode.

1 and 2 are partially exploded perspective and partial cross-sectional views of a field emission display device according to a first embodiment of the present invention, respectively.

3 is a partial plan view of a rear substrate of a field emission display device according to a second embodiment of the present invention;

4 and 5 are partially exploded perspective and partial cross-sectional views of a field emission display device according to a third embodiment of the present invention, respectively.

6 is a partial cross-sectional view of a rear substrate for explaining another configuration example of the emitter.

7 and 8 are partial plan views of a rear substrate and a cross-sectional view taken along line I-I of FIG. 7 of the field emission display device according to the fourth embodiment of the present invention, respectively.

9 and 10 are partial plan views and a cross-sectional view taken along line II-II of FIG. 9 of the field emission display device according to the fifth embodiment of the present invention, respectively.

11 and 12 are partial plan views of a rear substrate and a cross-sectional view taken along line III-III of FIG. 11, respectively, of the field emission display device according to the sixth exemplary embodiment.

FIG. 13 is a graph showing the characteristics of the anode current Ia according to the cathode-gate voltage difference Vcg.

14 is a schematic diagram showing an equipotential line distribution around an emitter in a field emission display according to the related art.

15 and 16 are schematic diagrams showing an equipotential line distribution around an emitter in the configuration of the fourth and fifth embodiments of the present invention, respectively.

FIG. 17 is a graph illustrating measurement of field strength applied to an emitter in a field emission display device according to the related art and a field emission display device according to fourth and fifth embodiments of the present invention; FIG.

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

A gate electrode formed in a line pattern on one surface of the rear substrate, an insulating layer formed on the front surface of the rear substrate while covering the gate electrodes, and a line pattern vertically intersecting with the gate electrode on the insulating layer and crossing the gate electrode. A cathode electrode forming a through portion in each pixel region, a carbon-based electron source located on a cathode electrode adjacent to one side of the through portion, an anode formed on one surface of the front substrate facing the rear substrate, and an anode A field emission display device including a fluorescent film positioned on an electrode surface is provided.

The cathode electrode may form a main through portion and an auxiliary through portion in the pixel area side by side along the longitudinal direction of the cathode electrode. In this case, the surface electron source may have a cathode adjacent to one side of the main through portion facing the auxiliary through portion. It is located on the electrode.

The cathode electrode may form a counter electrode inside the through part, and the counter electrode is electrically connected to the gate electrode by contacting the gate electrode through the through hole of the insulating layer. At this time, the counter electrode is kept at a constant distance from the cathode in the through part to prevent the short with the cathode.

A counter electrode may be positioned between the cathode electrodes, and a main counter electrode may be positioned between the cathode electrodes and an auxiliary counter electrode may be positioned inside the through part.

In this case, the surface electron source is located on the counter electrode or on the cathode electrode between the main counter electrode and the through portion. In addition, the cathode electrode has a short width portion and a long width portion on both sides of the penetrating portion in the longitudinal direction of the gate electrode, the short width portion is disposed opposite the counter electrode or the main counter electrode, and the surface electron source is positioned on the short width portion.

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

1 and 2 are partially exploded perspective and partial cross-sectional views of a field emission display device according to a first embodiment of the present invention, respectively.

As shown, the field emission display device includes a front substrate 2 and a rear substrate 4 which are arranged at random intervals to have an internal space, and the rear substrate 4 emits electrons by forming an electric field. The configuration, and the front substrate 2 is provided with a configuration for implementing a predetermined image by the former.

More specifically, the rear substrate 4 has a gate electrode 6 formed in a line pattern along the X-axis direction of the drawing, and covers the gate electrodes 6 and the insulating layer 8 on the front surface of the rear substrate 4. Is formed, and a plurality of cathode electrodes 10 are formed on the insulating layer 8 in a line pattern along the Y-axis direction of the drawing to vertically cross the gate electrode 6.

In the cathode electrode 10, a through portion 12 is formed at an intersection point of the gate electrode 6, that is, each pixel region to expose the insulating layer 8. A surface electron source, that is, an emitter 14, made of a carbonaceous material is positioned on the adjacent cathode electrode 10.

The penetrating portion 12 may be formed in other shapes in addition to the illustrated rectangle, and the emitter 14 may be adjacent to any one of four sides of the penetrating portion 12 in particular parallel to the gate electrode 6. It is preferable to form the line pattern parallel to the gate electrode 6 on the cathode electrode 10.

Here, the emitter 14 is made of a carbon-based material including carbon nanotubes, graphite, diamond like carbon (DLC), C ₆₀ (fullerene), and the like. The material may be prepared in paste form, and then screen printed onto the cathode electrode 10 to form the emitter 14.

The front substrate 2 includes a transparent anode electrode 16 to which a high voltage (approximately 1 to 5 kV) required for electron acceleration is applied, and a fluorescent film 18 excited by electrons to emit visible light. 2 and the back substrate 4 maintain a constant cell gap by the plurality of spacers 20 while keeping the interior in a vacuum state.

According to the above-described configuration, when a predetermined direct current or alternating voltage is applied between the cathode electrode 10 and the gate electrode 6, and a high voltage is applied to the anode electrode 16, the cathode electrode 10 and the gate electrode 6 are applied. An electric field is formed around the emitter 14 due to the difference in voltage, and electrons are emitted from the emitter 14, and the emitted electrons reach the corresponding fluorescent film 18 by the anode voltage. ) To emit light.

In this case, since the through part 12 exposing the insulating layer 8 is formed inside the cathode electrode 10 by excluding the conductive material constituting the cathode electrode 10, it is induced by the gate electrode 6. An electric field is easily formed through the insulating layer 8 over a larger area around the emitter 14. Therefore, the through part 12 lowers the emission start voltage and the driving voltage, and serves to enlarge the field emission region.

In addition, since the emitter 14 is positioned inside the cathode electrode 10 instead of the edge of the cathode electrode 10, the conductive material constituting the cathode electrode 10 is the cathode electrode 10 or the neighboring pixel of the neighboring pixel. It serves to block the penetration of the electric field into the emitter 14 by the voltage applied to the gate electrode (6).

Therefore, the neighboring effect phenomenon in which the electric field intensity around the specific emitter 14 is changed by the voltage applied to the gate electrode 6 of the neighboring pixel is reduced. As a result, the color purity is reduced by suppressing light emission of the adjacent pixel. Improve the brightness imbalance.

In the second embodiment, the field emission display device according to the present invention has a main through portion 22 along the longitudinal direction of the cathode electrode 10 in each pixel region of the cathode electrode 10, as shown in FIG. Provides a configuration in which the auxiliary through portion 24 is formed, and the emitter 14 is formed on the cathode electrode 10 adjacent to one side of the main through portion 22 opposite the auxiliary through portion 24. .

Like the main through part 22, the auxiliary through part 24 exposes the insulating layer 8 by excluding the conductive material constituting the cathode electrode 10, and insulates the electric field of the gate electrode 6. Layer 8 allows for easier formation over a wider area around emitter 14. Therefore, this embodiment has an effect of further lowering the emission start voltage and the driving voltage as compared with the previous embodiment.

In the present exemplary embodiment, the auxiliary through part 24 is set such that the distance d1 between the main through parts 22 located in the neighboring pixels is larger than the distance d2 from the emitter 14 located in the corresponding pixel. The star driving is smoothly performed, and electric field penetration by the voltage applied to the gate electrode 6 of the neighboring pixel is blocked.

4 and 5 are partially exploded perspective views and partial cross-sectional views of a field emission display device according to a third exemplary embodiment of the present invention, respectively. In this embodiment, the length of the cathode electrode 10 in each pixel region of the cathode electrode 10 is shown. The emitter is formed on the cathode electrode 10 adjacent to one side of the main through part 22 which is formed in the main through part 22 and the auxiliary through part 24 along the direction, and which is opposite to the auxiliary through part 24. 14 is formed, and a counter electrode 26 electrically connected to the gate electrode 6 is formed in the main through portion 22.

That is, in the main through part 22, a through hole 8a having a smaller diameter than the main through part 22 and penetrating the insulating layer 8 to expose the gate electrode 6 is formed. A counter electrode 26 made of a conductive material is formed at 8a and electrically connected to the gate electrode 6. Preferably, the counter electrode 26 is formed to have a smaller size than the main penetrating portion 22 to prevent the short from the emitter 14, and maintain a constant distance from the cathode electrode 10.

Therefore, when the counter electrode 26 is applied with a predetermined driving voltage to the gate electrode 6 to form an electric field for electron emission between the emitter 14, the counter electrode 26 itself is also the emitter 14. Forming an electric field for electron emission toward the lowering the driving voltage of the field emission display device.

Meanwhile, in the above-described embodiment, the emitter 14 emitting electrons by forming an electric field may be formed not only on the top surface of the cathode electrode 10 but also on the top surface and the side surface of the cathode electrode 10, and the cathode in FIG. 6. An emitter 14 'formed over the top and sides of the electrode 10 is shown.

FIG. 7 is a partial plan view of a rear substrate of a field emission display device according to a fourth exemplary embodiment of the present invention. FIG. 8 is a cross-sectional view taken along line II of FIG. 7, and the present exemplary embodiment is a cross-sectional view of each pixel region of the cathode electrode 10. A through portion 12 is formed, and a counter electrode 28 electrically connected to the gate electrode 6 is formed between each cathode electrode 10, and the cathode electrode 10 opposite to the counter electrode 28 is formed. It consists of a structure in which the emitter 14 is formed at one edge. The counter electrode 28 is in contact with the gate electrode 6 through the through hole 8a formed in the insulating layer 8 to maintain the same potential as the gate electrode 6.

As the counter electrode 28 and the penetrating portion 12 are positioned at both the left and right sides of the emitter 14, the electric field of the gate electrode 6 is driven by the counter electrode 28 in the driving process. In addition to being provided on one side, it is provided together on the other side of the emitter 14 via the insulating layer 8 exposed by the penetrating portion 12. The present embodiment thus forms an electric field over a larger area around the emitter 14, effectively extending the field emission area.

At this time, the cathode electrode 10 has a rectangular through portion 12 formed therein, and the long width portion 10A along the longitudinal direction of the gate electrode 6 on both sides of the through portion 12 (A in the drawing). And a short width portion 10B (in the drawing, a width of B), the short width portion 10A is disposed opposite the counter electrode 28 of the pixel, and the emitter 14 is placed thereon. It is preferable to form.

This is because as the width of the short width portion 10A decreases, the electric field of the gate electrode 6 has a greater influence on the emitter 14 through the penetrating portion 12, so that the electric field strength applied to the emitter 14 becomes higher. This results in an increase in the amount of electron emission resulting in an increase in screen brightness. On the other hand, since the conductivity of the cathode electrode 10 is lowered by the through part 12, the long width portion 10B is formed to have a larger width than the short width portion 10A to ensure conductivity.

FIG. 9 is a partial plan view of a rear substrate of a field emission display device according to a fifth exemplary embodiment of the present invention, and FIG. 10 is a cross-sectional view taken along the line II-II of FIG. 9, and the present embodiment is a pixel of the cathode electrode 10. A through portion 12 is formed in the region, a main counter electrode 30 electrically connected to the gate electrode 6 is formed between each cathode electrode 10, and the gate electrode 6 is formed in the through portion 12. An auxiliary counter electrode 32 electrically connected to the second counter electrode 32 is formed, and an emitter 14 is formed at one edge of the cathode electrode 10 opposite to the main counter electrode 30.

The main counter electrode 30 and the auxiliary counter electrode 32 contact the gate electrode 6 through respective through holes 8a and 8b formed in the insulating layer 8, and preferably, the auxiliary counter electrode 32. The silver is formed to a size smaller than the through part 12 so as to maintain a constant distance from the cathode electrode 10 and the emitter 14 so that a short circuit with the cathode electrode 10 does not occur.

As the main counter electrode 30 and the auxiliary counter electrode 32 are positioned at both left and right sides of the emitter 14, the electric field of the gate electrode 6 is driven through the main counter electrode 30 during the driving process. At the same time as one side of the 14, it is provided together with the other side of the emitter 14 through the auxiliary counter electrode (32). Thus, this embodiment forms a stronger electric field around the emitter 14 over a wider area to expand the field emission region and increase the field strength applied to the emitter 14.

Meanwhile, in the field emission display device according to the present invention, all or part of the emitter 14 is formed between the cathode electrode 10 and the insulating layer 8, that is, under the cathode electrode 10 and formed on the front substrate 2. Reducing the opposing area of anode electrode 16 and emitter 14 prevents direct damage to emitter 14 by arcing. The above configuration will be described with reference to the above-described configuration of the third embodiment.

FIG. 11 is a partial plan view of a rear substrate of a field emission display device according to a sixth embodiment of the present invention, and FIG. 12 is a cross-sectional view taken along line III-III of FIG. 11, wherein the emitter 34 is an insulating layer in this embodiment. (8) In each pixel area, the electrodes are formed in the shape of a rod perpendicular to the cathode electrode 10, and the cathode electrode 10 is formed on the insulating layer 8 while covering all or part of these emitters 34. . In addition, in each pixel area of the cathode electrode 10, a main through part 22 and an auxiliary through part 24 penetrating the cathode electrode 10 are positioned. Preferably, a part of the emitter 34 is disposed in the main through part ( 22) Expose internally.

As such, in the structure in which the cathode electrode 10 covers the emitter 34, even if an arcing phenomenon occurs because an electric field between the cathode electrode 10 and the anode electrode 16 increases due to the high voltage applied to the anode electrode 16. Since a high density arcing current flows to the cathode electrode 10, a higher voltage can be applied to the anode electrode 16 without directly affecting the emitter 34.

According to the experiments of the present inventors, when the distance between the cathode electrode 10 and the anode electrode 16 is 1 mm, a high voltage of approximately 5 kV can be applied to the anode electrode 16, so that the degree of vacuum inside the display device is appropriately maintained. In this case, a high brightness screen can be realized without deterioration of the emitter 34.

As described above, the present invention in which a through portion is formed inside a cathode electrode and an emitter is arranged on a cathode electrode adjacent to one side of the through portion has a first effect to alleviate the variation in electron emission characteristics between emitters of each pixel. It prevents navering effects, and as a result, increases the color purity of the screen and improves the luminance imbalance.

In addition, the above-described structure makes it possible to drive the same polarity by applying a positive scan pulse to the gate electrode and a positive data pulse to the cathode by mitigating the variation in electron emission characteristics between emitters. The inventor tested the electron emission by adjusting the voltage applied to the gate electrode and the cathode as shown in Table 1, and the results are shown in Table 1.

More specifically, according to the line-sequential mode, 100V is applied to the gate electrode, 0V is applied to the unselected gate electrode, and 0V is applied to the gate electrode in an on condition. Was applied and a voltage of 50 V was applied in the off condition.

As a result, it was confirmed that electron emission selectively occurs in the pixel at the point where the gate electrode to which 100V is applied and the cathode electrode to which 0V is applied are generated, and electron emission does not occur in three other cases. The gray scale implementation when the display device is driven may apply a pulse width modulation method.

Cathode electrode OV 50 V Gate electrode 100 V Pixel ON Pixel OFF 0 V Pixel OFF Pixel OFF

FIG. 13 is a graph showing the characteristics of the anode current Ia according to the cathode-gate voltage difference Vcg, where Vt is the threshold voltage at which electron emission starts and pixel display voltage at which Von satisfies the current level required for pixel display. Means. In the graph, the dotted line represents the current-voltage (I-V) curve for each pixel, and the I-V curve in which the solid line reflects the actual driving.

In a typical field emission display device, an electric field formed on a cathode electrode is sensitive to a distance from a neighboring cathode electrode and geometrical shape characteristics of the electrode, and thus emits between pixels under the same voltage conditions due to process tolerances in manufacturing a large area display device. The difference in current becomes relatively large. Accordingly, the anode current Ia according to the cathode-gate voltage Vcg for each pixel shows a deviation as shown.

As a result, in order to alleviate non-uniform display characteristics of each pixel, the threshold voltage Vt should be matched to pixels having excellent characteristics, and the pixel display voltage Von should be matched to pixels having poor characteristics. The drive voltage level should be set to reflect this. In this case, the I-V curve of one pixel becomes experimentally the following condition (1). However, the following condition (2) is satisfied in the solid I-V curve applied to actual driving.

Von = 2 × Vt ------ (1)

Von> 2 × Vt ------ (2)

In the above case, the conventional field emission display device applied a negative scan pulse to the cathode electrode and a positive data pulse to the gate electrode under the following condition (3).

Von = Vscan (scan voltage) + Vdata (data voltage) ------ (3)

In this case, in one or more cases in which at least one of the cathode electrode and the gate electrode is turned off, although the field emission of the pixel should not occur, one or two off conditions are caused by the above-described naming effect phenomenon. Field emission occurs at, which leads to a lower contrast of the screen.

However, the field emission display device according to the present invention uses the gate electrode as the scan electrode, the cathode electrode as the data electrode, and can apply the same polarity to apply a positive pulse to both electrodes. Deterioration of the contrast characteristic can be prevented even in a nonuniform large area display device.

That is, for example, when the pixel display voltage Von is 120V and the threshold voltage Vt is 50V, 120V (120V when selected, 0V when not selected) is applied to the gate electrode and the data is applied to the cathode electrode. When 70 V (0 V in on condition and 70 V in off condition) is applied as the voltage, the OFF state is correctly maintained in all three off conditions in Table 1 described above.

In addition, the present invention extends the field emission region to increase the field strength applied to the emitter as a second effect, and improve the electron emission effect. The above effect is particularly evident in the configuration of the fourth embodiment of the present invention in which the emitter is disposed between the counter electrode and the penetrating portion, and the fifth embodiment of the present invention in which the emitter is disposed between the main counter electrode and the auxiliary counter electrode. Appears.

FIG. 14 is a schematic view showing an equipotential line distribution around an emitter in a field emission display according to the related art without a through part and a counter electrode as a comparative example of the present invention, and FIGS. A schematic diagram showing the equipotential line distribution around the emitter in the configuration of the fourth embodiment and the configuration of the fifth embodiment. At this time, the driving conditions used in the experiment are shown in Table 2 below.

Cathode electrode voltage (V) -100 Gate electrode voltage (V) 60 Anode electrode voltage (V) 600

First, referring to the field emission display of the comparative example, since the equipotential line surrounds the entire cathode electrode 1 and the cathode electrode 1 is wide, the dense portion of the equipotential line that induces electron emission, that is, the field emission region It can be seen that (circled in the drawing) is distributed around the edge of the cathode electrode 1, that is, around the emitter.

On the other hand, in the configuration of the fourth and fifth embodiments of the present invention, the equipotential lines are densely enclosed by the cathode electrode 10, and the field emission region is expanded, and the equipotential lines are densely distributed around the emitter 14. can confirm. Further, in the configuration of the fifth embodiment, the auxiliary counter electrode 32 pushes the equipotential lines toward the cathode electrode 10 to induce a better electron emission effect.

FIG. 17 is a graph illustrating measurement of electric field strength applied to an emitter in a field emission display device (comparative example) according to the related art and a field emission display device according to fourth and fifth embodiments of the present invention. In the graph, the horizontal axis is the electric field measurement position, and the electric field at the position was measured at 0.2 μm intervals toward the inside of the cathode electrode based on the emitter tip.

In the above graphs, Example 1 and Example 3 are cases in which the width of the short width portion (10A in FIG. 8) is 50 µm and 20 µm in the configuration of the fourth embodiment of the present invention, respectively. 4 shows the case where the width | variety of the short width part (10A in FIG. 10) is 50 micrometers and 20 micrometers in the structure of 5th Example of this invention, respectively. At this time, the width of the cathode electrode was 250 µm in both Comparative Examples and Examples 1-4.

As shown, it can be seen that Examples 1 to 4 form stronger electric fields in the entire measurement area as compared with the field emission display of Comparative Example. Compared with Examples 1 to 4, the smaller the width of the cathode electrode 10 in contact with the emitter 14, that is, the width of the small portion 10A where the emitter 14 is located, the stronger the electric field is formed. When the widths of the narrow portions 10A are the same, the structure of the fifth embodiment in which the auxiliary counter electrode 32 is formed in the penetrating portion 12 is the fourth embodiment in which the auxiliary counter electrode is not formed in the penetrating portion 12. It forms an electric field stronger than the example structure.

The following Table 3 summarizes the results of the above experiments, and the length of the field emission region is obtained by calculating the length of the region representing the electric field above the off field, which is proportional to the width of the field emission region. , The average electric field is the sum of the electric fields divided by the length of the field emission region, where k in the unit is the proportional constant.

Length of field emission area (μm) Average electric field (kV / µm) Field emission current (A) Comparative example 1.6 11.843 127.17 Example 1 2.2 (137.5%) 12.260 (103.5%) 184.14 (144.8%) Example 2 2.4 (150.0%) 12.857 (108.6%) 220.35 (173.3%) Example 3 3.0 (187.5%) 12.791 (108.0%) 270.55 (212.7%) Example 4 3.2 (200.0%) 12.812 (108.2%) 289.26 (227.5%)

(* The numerical values in parentheses in the above table indicate the ratios of the results of each example to the comparative example, assuming that the result of the comparative example is 100.)

As shown in the above table, it can be seen that in the case of Examples 1 to 4, the field emission region is expanded, and the intensity of the average electric field and the field emission current are higher than those of the comparative example. In particular, in Example 4, in which the main counter electrode and the auxiliary counter electrode were formed at the same time and the width of the narrow portion where the emitter is located was set to 20 µm, the average electric field was 108.2% and the field emission current was higher than that of the comparative example. 227.5% improved results.

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.

As described above, according to the present invention, the color purity of the screen is improved and the luminance imbalance is improved by preventing the navering effect phenomenon in which the electric field intensity around the specific emitter is changed by the voltage applied to the gate electrode of the neighboring pixel. In addition, since the same polarity driving that applies (+) scan pulse and (+) data pulse to the gate electrode and the cathode electrode is possible, high contrast can be realized when manufacturing a large area display device. In addition, a strong electric field can be formed around the emitter over a wider area, increasing the field emission current to improve the brightness of the screen.

Claims (22)

Front and rear substrates disposed to face each other at random intervals; A gate electrode formed in a line pattern on one surface of a rear substrate facing the front substrate; An insulating layer formed on an entire surface of a rear substrate while covering the gate electrodes; A cathode electrode formed in a line pattern perpendicular to the gate electrode on the insulating layer, and forming a through portion in each pixel region crossing the gate electrode; A carbon-based electron source positioned on a cathode electrode adjacent to one side of the through part; An anode formed on one surface of the front substrate facing the rear substrate; And And a fluorescent film on the surface of the anode. The method of claim 1, And at least one material selected from the group consisting of carbon nanotubes, graphite, diamond-like carbon, and C ₆₀ (fullerene). The method of claim 1, Wherein the through portion is formed in a quadrangle, and the surface electron source is positioned on a cathode electrode adjacent to the side of one of the four sides of the through portion parallel to the gate electrode. The method of claim 1, And a cathode and a cathode formed in the pixel area in parallel with each other in the pixel area along the length of the cathode electrode. The method of claim 4, wherein And the surface electron source is positioned on a cathode electrode adjacent to either side of the main through portion facing the auxiliary through portion. The method of claim 4, wherein And a distance between the auxiliary through part and the main through part positioned in the neighboring pixel is greater than the distance between the main through part located in the same pixel and the surface electron source. The method of claim 1, A counter electrode is formed in the through portion of the cathode electrode, and the counter electrode is in contact with the gate electrode through the through hole of the insulating layer and electrically connected to the gate electrode. The method of claim 7, wherein And a counter electrode positioned at a constant distance from the cathode in the through part. The method of claim 1, The cathode electrode forms a main through portion and an auxiliary through portion in parallel in the longitudinal direction of the cathode in each pixel area, forms a counter electrode inside the main through portion, and the counter electrode passes through the through hole of the insulating layer. And a field emission display in electrical contact with the gate electrode. The method of claim 9, And a counter electrode positioned at a constant distance from the cathode in the main through portion. The method of claim 1, And a counter electrode disposed between the cathode electrodes, the counter electrode being in contact with the gate electrode through a through hole of the insulating layer and electrically connected to the gate electrode. The method of claim 11, And the surface electron source is on a cathode electrode between the counter electrode and the through part. The method of claim 11, And the cathode electrode has a short width portion and a long width portion on both sides of the through portion along a length direction of the gate electrode, the short width portion is disposed opposite the counter electrode, and the surface electron source is positioned on the short width portion. The method of claim 1, A main counter electrode is formed between the cathode electrodes, an auxiliary counter electrode is formed inside the through portion of the cathode electrode, and the main counter electrode and the auxiliary counter electrode are in contact with the gate electrode through the through hole of the insulating layer, respectively. Field emission indicator connected to the The method of claim 14, And the surface electron source is on a cathode electrode between the main counter electrode and the auxiliary counter electrode. The method of claim 14, And the cathode electrode has a short width portion and a long width portion on both sides of the through portion along a length direction of the gate electrode, the short width portion is disposed opposite the main counter electrode, and the surface electron source is positioned on the short width portion. The method of claim 1, And the surface electron source is formed over the top and side surfaces of the cathode electrode. The method of claim 1, And the cathode electrode is formed on the insulating layer, and the cathode electrode is formed on the surface electron source while covering all or part of the surface electron source. Front and rear substrates disposed to face each other at random intervals; A gate electrode formed in a line pattern on one surface of a rear substrate facing the front substrate; An insulating layer formed on an entire surface of a rear substrate while covering the gate electrodes; A cathode electrode formed in a line pattern perpendicular to the gate electrode on the insulating layer, and forming a through portion in each pixel region crossing the gate electrode; A counter electrode electrically connected to the gate electrode through a through hole from which a portion of the insulating layer is removed, and positioned between the cathode electrode; A carbon interface electron source positioned on the cathode electrode between the through portion and the counter electrode; An anode formed on one surface of the front substrate facing the rear substrate; And And a fluorescent film on the surface of the anode. The method of claim 19, And the cathode electrode has a short width portion and a long width portion on both sides of the through portion along a length direction of the gate electrode, the short width portion is disposed opposite the counter electrode, and the surface electron source is positioned on the short width portion. The method of claim 19, A sub counter electrode is formed in the through portion of the cathode electrode, and the sub counter electrode is in contact with the gate electrode through the through hole of the insulating layer and electrically connected to the gate electrode. A driving method of the field emission display device according to claim 1, Sequentially applying positive scan pulses to the gate electrodes; And applying a positive data pulse to a cathode electrode crossing the gate electrode selected by the scan voltage.