KR20050066585A - Field emission display device - Google Patents

Abstract

The present invention relates to a field emission display device capable of focusing electrons emitted from an emitter to suppress color bleeding, and to increase screen luminance by increasing an amount of electron emission, comprising: first and second substrates; Gate electrodes formed on the first substrate; Cathode electrodes formed over the gate electrodes with an insulating layer interposed therebetween; Opposing electrodes electrically connected to the respective gate electrodes and disposed on the insulating layer at predetermined intervals from the cathode electrodes between any of the cathode electrodes; An electron emission source provided on the cathode electrode at an arbitrary distance from each counter electrode, and the electron emission sources provided on the two cathode electrodes adjacent to each other form one counter electrode positioned between the cathode electrodes; A shared field emission display is provided.

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, and more particularly, to a field emission display having an emitter made of a carbon-based material and having a gate electrode for controlling electron emission of the emitter disposed under the cathode. .

In the field of field emission display (FED), an emitter which is an electron emission source through a thick film process such as screen printing using a carbon-based material that emits electrons well under low voltage (approximately 10 to 100V) driving conditions The technology for forming the film is being researched and developed.

According to the technical trends so far, graphite, diamond-like carbon and carbon nanotubes are known as carbon-based materials suitable for emitters, and among them, carbon nanotubes Is expected to be an ideal electron emitting material by emitting electrons well even in a low electric field of about 1 to 10V / µm. Emitters using carbon nanotubes and related arts related to the fabrication of the emitters include US Pat. Nos. 6,359,383 and 6,436,221.

Meanwhile, when the field emission display device has a triode structure having a cathode, a gate, and anode electrodes, the gate electrode 3 is formed on the rear substrate 1 as shown in FIGS. 7 and 8, and the gate electrode After the insulating layer 5 is formed on the insulating layer 5, the cathode electrode 7 and the emitter 9 are disposed on the insulating layer 5, and the anode electrode 13 and the fluorescent light are formed on the front substrate 11. The configuration in which the film 15 is formed is known.

Thus, when a predetermined driving voltage is applied to the cathode electrode 7 and the gate electrode 3, an electric field is formed around the emitter 9 due to the voltage difference between the two electrodes, and electrons are emitted from the emitter 9, The emitted electrons are attracted to the front substrate 11 by the high voltage applied to the anode electrode 13. The electrons collide with the fluorescent film 15 corresponding to the emitter 9 to emit light, thereby performing a predetermined display.

In the above structure, there is no fear that the gate electrode 3 and the cathode electrode 7 are short-circuited during the fabrication process, and the emitter 9 is located at the top of the rear substrate 1 so that a thick film process such as screen printing can be easily applied. In addition, the manufacturing process is relatively simple, which is advantageous in manufacturing a large area display device.

However, in the above-described structure, since there are no members for assisting the electron beam focusing around the emitter 9, electrons are emitted radially from the emitter 9 when the display device is driven so that the emitter 9 is moved up and down and left and right. A beam spreading phenomenon in which the electron beam spreads in all directions occurs.

Therefore, in the conventional field emission display, as shown in FIG. 8, the electron beam emitted from one emitter 9 is not only the fluorescent film 15 corresponding to the emitter 9 but also the fluorescent film of the neighboring pixels. Reaching 15 'and emitting light causes color bleeding, and screen quality is degraded due to electron beam dispersion.

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 capable of focusing electrons emitted from an emitter, suppressing color blurring, and increasing screen brightness to improve screen quality. It is.

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

First and second substrates disposed at random intervals, gate electrodes formed on the first substrate, cathode electrodes formed on the gate electrodes with an insulating layer interposed therebetween, and the respective gate electrodes. Opposing electrodes disposed on the insulating layer at predetermined intervals between the cathode electrodes and connected to any of the cathode electrodes, an electron emission source provided on the cathode electrode at random intervals with each of the opposing electrodes, and the second electrode; An anode electrode formed on the substrate and fluorescent films positioned on one surface of the anode electrode, and electron emission sources provided on two neighboring cathode electrodes share one opposite electrode positioned between the cathode electrodes; It provides a field emission display device.

The cathode electrodes include first and second cathode electrodes disposed adjacent to each other, and an opposite electrode positioned between the first and second cathode electrodes extends toward the center of the first and second cathode electrodes, respectively. The electron emission source is disposed towards the extension at any distance from the extension.

At least two extension parts may be provided with respect to the first and second cathode electrodes. In this case, an electron emission source may be provided corresponding to the number of extension parts, and each electron emission source may be extended at an interval from the extension part. Placed towards wealth.

The counter electrode may be disposed between each row of cathode electrodes, wherein an electron emission source is disposed at both edges of the cathode electrode.

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

First and second substrates, gate electrodes formed on the first substrate, cathode electrodes formed on the gate electrodes with an insulating layer therebetween, and arbitrary cathode electrodes electrically connected to the respective gate electrodes. Opposing electrodes formed on the insulating layer at regular intervals from the cathode electrode therebetween, at least one pair of extensions extending from the opposing electrode toward the center of two neighboring cathode electrodes, and extending at any interval from the extension portion; These cathode electrodes include electron emission sources disposed toward the negative electrode, an anode electrode formed on the second substrate, and fluorescent films positioned on one surface of the anode electrode, and electron emission sources provided on two neighboring cathode electrodes. One opposing electrode positioned between them, and the electron beam emission trajectories of these electron emission sources are made in opposite directions System provides an emission display.

The counter electrode may be located between these cathode electrodes for every two rows of cathode electrodes or between the cathode electrodes of every row. The extension part has a shape extending sequentially from the opposite electrode along the width direction of the cathode electrode and the longitudinal direction of the cathode electrode.

The electron emission source is made of any one or combination of carbon nanotubes, graphite, diamond-like carbon, C ₆₀ (fulleren).

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

1 is a partial plan view of a first substrate of a field emission display device according to a first exemplary embodiment of the present invention, and FIGS. 2 and 3 are cross-sectional views of the field emission display device viewed from the direction AA and BB of FIG. 1, respectively. to be.

Referring to the drawings, the field emission display device includes a first substrate 2 and a second substrate 4 which are disposed to face each other at arbitrary intervals and constitute a vacuum container. The first substrate 2 is provided with a configuration for emitting electrons by forming an electric field, and the second substrate 4 is provided with a configuration for emitting visible light by the electrons to implement a predetermined image.

More specifically, the gate electrodes 6 are formed in a stripe pattern along one direction (Y direction in the drawing) on the first substrate 2, and cover the gate electrodes 6 on the entire inner surface of the first substrate 2. The insulating layer 8 is located. On the insulating layer 8, cathode electrodes 10 are formed along a direction crossing the gate electrode 6 (X direction in the drawing), and an emitter 12, which is an electron emission source, is formed at one edge of the cathode electrode 10. Located.

The counter electrode 14 is positioned between the cathode electrodes 10 in every two rows of the cathode electrodes 10, and the emitter 12 is disposed at one edge of the cathode electrode 10 on which the counter electrodes 14 are positioned. Is placed. Thus, two emitters 12 provided on two cathode electrodes 10 adjacent to each other share one counter electrode 14. The opposite electrode 14 is in contact with and electrically connected to the gate electrode 6 through a via hole 8a formed in the insulating layer 8, and between the cathode electrodes 10. ) And at regular intervals.

For convenience of description, when the two cathode electrodes 10 shown in FIG. 1 are referred to as the first and second cathode electrodes 10a and 10b, the counter electrode 14 is referred to as the first and second cathode electrodes 10a and 10b. A pair of extensions 16 are formed, respectively, extending toward the center of the crankcase. The extended portion 16 is preferably sequentially formed along the width direction of the cathode electrode 10 and the length direction of the cathode electrode 10 from the opposite electrode 14 to have a “??” shape. In addition, the first and second cathode electrodes 10a and 10b form a protrusion 18 positioned between the counter electrode 14 and the extension 16, and one side of the protrusion 18 facing the extension 16. Emitter 12 is located at the edge.

As a result, when a predetermined driving voltage is applied to the first cathode electrode 10a and the gate electrode 6 in the center of the three gate electrodes 6 shown in FIG. 1, the two electrodes are separated by the voltage difference between the two electrodes. An electric field is formed around the emitter 12 disposed in the intersection area, and electrons are emitted from one edge of the emitter 12 facing the extension electrode 16 of the counter electrode 14 (see dotted arrow in FIG. 1). .

Thus, two emitters 12 sharing one opposing electrode 14 selectively emit electrons according to a driving signal applied to the cathode electrode 10, and electron beams emitted from the two emitters 12. The trajectory is in a direction opposite to each other (see FIG. 2), and an intersection region of the cathode electrode 10 and the gate electrode 6 is defined as one unit pixel region (see C dotted line in FIG. 1).

In the present invention, the emitter 12 is made of any one or combination of carbonaceous materials, such as carbon nanotubes, graphite, diamond-like carbon, C ₆₀ (fulleren).

An anode electrode 20 is formed on one surface of the second substrate 4 opposite to the first substrate 2, and red, green, and blue fluorescent films 22 and black are formed on one surface of the anode electrode 20. A fluorescent screen 26 consisting of a film 24 is formed. The anode electrode 20 is made of a transparent electrode such as indium tin oxide (ITO). On the other hand, the surface of the fluorescent screen 26 may be a metal film (not shown) to increase the brightness of the screen by the metal back (metal back) effect, in which case the transparent electrode is omitted and the metal film to function as an anode electrode Can be.

The field emission display device configured as described above is driven by supplying a predetermined voltage to the gate electrode 6, the cathode electrode 10, and the anode electrode 20 from the outside. For example, the gate electrode 6 has several to several tens of times. The positive voltage of the volts is applied to the cathode electrode 10 with the negative voltage of several to several tens of volts, and the anode electrode 20 with the hundredth to several thousand volts of the positive voltage.

As a result, an electric field is formed around the emitter 12 due to the voltage difference between the gate electrode 6 and the cathode electrode 10, and electrons are emitted from the edge of the emitter 12 facing the extension 16. The electrons are attracted by the high voltage applied to the anode electrode 20 to the second substrate 4 and collide with the fluorescent film 22 of the corresponding unit pixel to emit a predetermined image.

In this case, the field emission display according to the present exemplary embodiment has the structure in which the emitter 12 is surrounded by three directions by the cathode electrode 10 to which the negative voltage is applied, thereby suppressing electron beam spreading. Has

That is, referring to FIG. 1, since the emitter 12 of one unit pixel has a structure in which left and right sides are surrounded by the cathode electrode 10, the emitter 12 of one unit pixel is disposed at the negative potential of the cathode electrode 10 when the electron beam is emitted. This suppresses the beam spreading and has the effect of focusing the electron beam in the X direction of the drawing (in FIG. 1, the focusing force of the electron beam by the cathode electrode is shown by the solid arrow). Also, referring to FIG. 2, since the cathode electrode 10 is positioned along the electron beam emission direction with respect to the emitter 12 of one unit pixel, the beam is discharged by the negative potential of the cathode electrode 10 when the electron beam is emitted. Spreading is suppressed to have the effect of focusing the electron beam in the Y direction of the drawing (in FIG. 2, the focusing force of the electron beam by the cathode electrode is shown by a solid arrow).

Therefore, in the field emission display according to the present exemplary embodiment, electrons emitted from the emitter 12 of a specific unit pixel reach the fluorescent film 22 of the unit pixel intact, thereby preventing color bleeding and increasing color purity. The advantage of being concentrated in the fluorescent film 22 and increasing the screen brightness is expected.

In addition, in the present exemplary embodiment, since two cathode electrodes 10a and 10b share one counter electrode 14, an area occupied by the counter electrode 14 on the first substrate 2 may be reduced. Therefore, the width of the cathode electrode 10 can be wider than that of the conventional field emission display device. As a result, the current flow of the cathode electrode 10 can be improved to suppress the voltage drop of the cathode electrode 10. It is expected.

4 is a partial plan view of a first substrate of a field emission display device according to a second embodiment of the present invention.

Referring to the drawings, the present embodiment is based on the structure of the first embodiment described above, and the counter electrode 14 forms a plurality of, for example, two extension portions 28 toward the center of the first cathode electrode 10a. A plurality of, for example, two extension portions 28 are formed toward the center of the second cathode electrode 10b. In addition, the first cathode electrode 10a forms two protrusions 30 between the counter electrode 14 and the extension parts 28, and emitters are formed at one edge of the protrusion part 30 facing the extension part 28. 12) is arranged. The configuration of the protrusions 30 and emitters 12 described above is equally applied to the second cathode electrode 10b.

As a result, in the present exemplary embodiment, a plurality of emitters 12 are positioned in one unit pixel region C, for example, two emitters 12, and are positioned in one unit pixel by using a voltage difference between the cathode electrode 10 and the gate electrode 6. When the electrons are emitted from the emitter 12, the electrons are emitted from the two emitters 12 at the same time. Therefore, an advantage of increasing the electron emission amount and increasing the screen brightness is expected.

FIG. 5 is a partial plan view of a first substrate of a field emission display device according to a third exemplary embodiment of the present invention, and FIG. 6 is a cross-sectional view illustrating an assembled state of the field emission display device viewed from the D-D direction of FIG. 5.

Referring to the drawings, the present embodiment is based on the structure of the first embodiment described above, and the opposite electrodes 14 are disposed between the cathode electrodes 10 for every cathode electrode 10 in each row. The cathode electrode 10 forms emitters 12 at both edges of the counter electrode 14, each emitter 12 having an extension 16 extending from the counter electrode 14; It is arranged to face this extension 16 at any interval.

As a result, in the present exemplary embodiment, two emitters 12 are disposed at both edges of the unit pixel region C for each unit pixel region C. As shown in FIG. 6, one unit pixel region is driven. In doing so, two emitters 12 emit electrons toward the center of the unit pixel region. As a result, the present embodiment is expected to suppress the electron beam spreading and increase the electron beam emission amount as in the above-described embodiments, as well as increase the emission fidelity by emitting electrons toward the center of the fluorescent film 22.

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.

For example, a grid substrate in the form of a mesh for electron beam focusing may be mounted between the first substrate and the second substrate, in which case lower spacers are disposed between the first substrate and the grid substrate, and the second substrate and the grid substrate The upper spacers may be disposed between the first and second spacers to maintain a constant distance between the first and second substrates and the grid substrate.

As described above, according to the present exemplary embodiment, the color reproducibility is improved by suppressing electron beam spreading in the horizontal and vertical directions of the display device while maintaining the distance between the cathode electrodes or the cathode electrode and the counter electrode to such an extent that no process defect occurs. In addition, the width of the cathode electrode can be wider than that of the conventional field emission display device, thereby improving the current flow of the cathode electrode. In the above-described second and third embodiments, the electron beam emission amount is effectively increased to increase the screen brightness. The height is effective.

1 is a partial plan view of a first substrate of a field emission display device according to a first embodiment of the present invention.

2 and 3 are cross-sectional views illustrating an assembled state of the field emission display device viewed in the A-A direction and the B-B direction of FIG. 1, respectively.

4 is a partial plan view of a first substrate of a field emission display device according to a second embodiment of the present invention.

5 is a partial plan view of a first substrate of a field emission display according to a third exemplary embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating an assembled state of the field emission display device viewed from the direction D-D of FIG. 5.

7 is a partially exploded perspective view of a field emission display according to the related art.

8 is a partial cross-sectional view showing the assembled state of FIG.

Claims (12)

First and second substrates opposed to each other at arbitrary intervals; Gate electrodes formed on the first substrate; Cathode electrodes formed on the gate electrodes with an insulating layer interposed therebetween; Opposing electrodes electrically connected to the respective gate electrodes, the counter electrodes being disposed on the insulating layer at predetermined intervals from the cathode electrodes between arbitrary cathode electrodes; An electron emission source provided on the cathode electrode at a predetermined distance from each of the counter electrodes; An anode formed on the second substrate; And Comprising a fluorescent film located on any one surface of the anode, And the electron emission sources provided at the two adjacent cathode electrodes share one opposite electrode positioned between the cathode electrodes. The method of claim 1, An electric field including first and second cathode electrodes in which the cathode electrodes are disposed adjacent to each other, and an opposite electrode positioned between the first and second cathode electrodes extends toward a center of the first and second cathode electrodes, respectively; Emission indicator. The method of claim 2, And the electron emission source is disposed toward the extension at a predetermined distance from the extension. The method of claim 2, And at least two extension parts with respect to the first and second cathode electrodes. The method of claim 4, wherein And an electron emission source corresponding to the number of the expansion units, wherein each electron emission source is disposed toward the expansion unit at a predetermined distance from the expansion unit. The method of claim 1, And a counter electrode disposed between the cathode electrodes in each row. The method of claim 6, And the electron emission source is disposed at both edges of the cathode electrode. First and second substrates opposed to each other at arbitrary intervals; Gate electrodes formed on the first substrate; Cathode electrodes formed on the gate electrodes with an insulating layer interposed therebetween; Opposing electrodes electrically connected to the respective gate electrodes and formed on the insulating layer at predetermined intervals from the cathode electrodes between arbitrary cathode electrodes; At least one pair of extensions extending from the opposite electrode toward the center of two neighboring cathode electrodes; An electron emission source disposed toward the extension at an interval from the extension; An anode formed on the second substrate; And Comprising a fluorescent film located on any one surface of the anode, The electron emission sources provided in the two neighboring cathode electrodes share one opposite electrode positioned between the cathode electrodes, and the electron beam emission trajectories of the electron emission sources are in opposite directions. The method of claim 8, And a counter electrode disposed between the cathode electrodes every two rows of cathode electrodes. The method of claim 8, And a counter electrode disposed between the cathode electrodes in each row. The method of claim 8, And the extension portion extends from the opposite electrode in a sequential direction along the width direction of the cathode electrode and the longitudinal direction of the cathode electrode. The method according to claim 1 or 8, And the electron emission source is one of carbon nanotubes, graphite, diamond-like carbon, C ₆₀ (fulleren), or a combination thereof.