KR101009980B1 - Field Emission Display Device - Google Patents

Abstract

The gap between the grid plate and the anode electrode is set in the range of about 85 to 95% of the cell gap, and the gap between the grid plate and the cathode electrode is minimized so as to minimize beam spreading and prevent light emission. Is provided in the range of approximately 5 to 15% of the cell gap.

Field Emission Display, Cell Gap, Spacing, Beam Spread, Other Light Emitting, Spacer, Focusing, Distance

Description

Field emission display device

1 is a partially enlarged perspective view illustrating an embodiment of a field emission display device according to the present invention.

2 is a partially enlarged cross-sectional view illustrating an embodiment of a field emission display device according to the present invention.

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 which improves display quality of a screen by preventing beam spreading and minimizing color emission by maintaining a distance between electrodes in an appropriate range.

In general, a field emission display (FED) emits electrons from an emitter formed on the cathode electrode by using a quantum mechanical tunneling effect, and emits the emitted electrons by colliding with a fluorescent film formed on the anode electrode. As a flat panel display device for realizing a predetermined image, a triode structure consisting of a cathode electrode, a gate electrode, and an anode electrode is widely used.

In the conventional triode structured field display device, the first substrate and the second substrate are integrally bonded by a sealing material to form a vacuum container, and a plurality of gate electrodes and cathode electrodes are disposed on the first substrate with an insulating layer interposed therebetween. Are arranged in a cross pattern to form a stripe pattern, an emitter for emitting electrons to be connected to the cathode electrode, an anode electrode is formed of a transparent electrode such as an ITO thin film on the second substrate, and on the anode electrode Red (R), green (G), and blue (B) fluorescent films are alternately arranged with a black matrix therebetween.

In the field emission display device configured as described above, when a predetermined driving voltage is applied to the cathode electrode and the gate electrode, and a positive voltage of several hundred to several thousand volts is applied to the anode electrode, the voltage difference between the cathode electrode and the gate electrode is determined by the voltage difference. An electric field is formed around the emitter, whereby electrons are emitted, and the emitted electrons move toward the anode electrode to which a high voltage is applied, and impinge on the corresponding fluorescent film to emit a predetermined image display.

In the conventional field emission display device, a plurality of spacers are mounted between the first substrate and the second substrate to maintain a constant distance between the first substrate and the second substrate in response to the pressure applied to the vacuum container. In order to increase the focusing performance of the electron beam emitted from the emitter, a mesh plate grid plate having a plurality of beam passing holes formed at predetermined intervals is installed.

In the conventional field emission display device, a cell gap, which is a gap between the first substrate and the second substrate (actually, a gap between an anode electrode and a cathode electrode), is formed by setting a cell gap in a range of about 1 to 9 mm. do.                         

However, in the conventional field emission display, an appropriate range for the gap between the electrodes according to the cell gap has not been determined. Accordingly, when the gap between the cathode electrode and the grid plate is narrow, a short circuit occurs and the cathode electrode is damaged, and when the gap is wide, beam spreading at the bottom of the grid plate becomes severe. In addition, when the gap between the anode electrode and the grid plate is narrow, electron emission from the undesired cathode electrode (emitter) occurs due to diode emission, and in the wide case, the beam spreading on the grid plate becomes severe. Causes a problem.

When the beam spreading occurs, it is highly likely that other color emission occurs.

An object of the present invention is to solve the above problems, by setting the distance between the anode electrode and the grid plate and the distance between the cathode electrode and the grid plate of the appropriate range to minimize the beam spreading and prevent other colors emission high-quality screen An object of the present invention is to provide an electroluminescent display device capable of obtaining quality.

In the field emission display proposed by the present invention, the distance between the grid plate and the anode electrode is set in the range of about 85 to 95% of the cell gap, and the distance between the grid plate and the cathode electrode is about 5 to 15% of the cell gap. This is done by setting in the range of.

The cell gap means a gap between the cathode electrode formed on the first substrate and the anode electrode formed on the second substrate and is set at a predetermined interval according to the strength of the voltage applied to the anode electrode.

The intensity of the voltage applied to the anode electrode formed on the second substrate is set to several to several tens of kV, and the cell gap is set to a range of about 1 to 5 mm.

Next, a preferred embodiment of the field emission display device according to the present invention will be described in detail with reference to the drawings.

First, an embodiment of the field emission display device according to the present invention includes the first substrate 20 and the second substrate 22 disposed to face each other at a predetermined interval, as shown in FIGS. The gate electrode 24 and the cathode electrode 26 formed in the pattern which crosses each other on the board | substrate 20 with the insulating layer 25 interposed therebetween, and the cathode electrode 26 of the part which cross | intersects the said gate electrode 24 is carried out. ) An emitter 28 formed on the anode, an anode electrode 32 formed on the second substrate 22, a fluorescent film 34 formed in a predetermined pattern on one surface of the anode electrode 32, and In addition, a black matrix 50 formed between the fluorescent film 34 of the second substrate 22 and a plurality of beam passing holes 42 are disposed between the first substrate 20 and the second substrate 22. ) Includes a grid plate 40 formed by being arranged in a predetermined pattern.

The gate electrode 24 and the cathode electrode 26 are formed in a stripe pattern and arranged in a direction perpendicular to each other. For example, the gate electrode 24 is formed in a stripe pattern along the Y-axis direction of FIG. 1, and the cathode electrode 26 is formed in a stripe pattern along the X-axis direction of FIG. 1.

An insulating layer 25 is formed between the gate electrode 24 and the cathode electrode 26 over the entire area of the first substrate 20.                     

The emitter 28, which is an electron emission source, is formed at one edge of the cathode electrode 26 at each intersection of the gate electrode 24 and the cathode electrode 26.

The emitter 28 is a planar electron source having a uniform thickness, and is formed using a carbon-based material that emits electrons well under low voltage driving conditions of about 10 to 100V.

The carbon-based material forming the emitter 28 is selected from graphite, diamond, diamond like carbon (DLC), carbon nanotube (CNT), C ₆₀ (fulleren), and the like. It can be used individually or in combination of 2 or more types. In particular, carbon nanotubes are known to be ideal electron emission sources because the radius of curvature of the ends is extremely fine, such as several to several tens of nm, and thus emits electrons well even at low electric fields of about 1 to 10 V / μm.

Although the emitter 28 has been described as being formed of a surface electron source using a carbon-based material, the present invention is not limited thereto, and the present invention is not limited thereto, but may be a cone, wedge, or thin film edge. It is also possible to apply emitters of various shapes such as shapes.

In the above description, the gate electrode 24 is formed on the first substrate 20, and the cathode electrode 26 is formed on the first substrate 20 with the insulating layer 25 therebetween. However, the cathode electrode is formed on the first substrate 20. It is also possible to form the gate electrode 24 with the insulating layer 26 formed therebetween. In this case, a hole penetrating the gate electrode 24 and the insulating layer 25 is formed at the intersection of the cathode electrode 26 and the gate electrode 24, and the hole is exposed to the surface of the cathode electrode 26 exposed by the hole. Emitter 28 is formed.

In addition, as shown in FIGS. 1 and 2, the field emission display device according to the present invention has a gate electrode having a predetermined distance from each emitter 28 between the adjacent cathode electrodes 26. It is also possible to form the counter electrode 30 to raise the electric field of 24 over the insulating layer 25.

Since the counter electrode 30 is electrically connected to the gate electrode 24 through a via hole 31 formed in the insulating layer 25, a predetermined driving voltage is applied to the gate electrode 24. To form an electric field for electron emission with the emitter 28, the voltage of the gate electrode 24 is raised around the emitter 28 so that a stronger electric field is applied to the emitter 28 so that the emitter 28 It serves to ensure good electron emission from the rotor 28.

The anode electrode 32 formed on the second substrate 22 is formed of a transparent electrode having excellent light transmittance, such as an ITO thin film.

The fluorescent film 34 formed on the second substrate 22 has a red (R) fluorescent film 34R and a green (G) fluorescent film 34G along the gate electrode 24 direction (the Y-axis direction in FIG. 1). ), And the blue (B) fluorescent film 34B is alternately arranged one after the other at a predetermined interval.

In addition, a black matrix 50 is formed between the respective fluorescent films 34R, 34G, and 34B to improve contrast.

The fluorescent film 34 and the black matrix 50 may be formed in a stripe pattern, may be formed in a matrix pattern, and may be formed in various patterns such as a closed polygon, a circle, an oval, or the like by a pixel unit or a dot unit. It is also possible.

It is also possible to form a metal thin film layer 36 made of aluminum or the like on the fluorescent films 34R, 34G, 34B and the black matrix 50. The metal thin film layer 36 helps to improve withstand voltage characteristics and brightness.

The first substrate 20 and the second substrate 22 configured as described above are bonded by a sealing material (sealing material) at predetermined intervals in a state where the cathode electrode 26 and the fluorescent film 34 face each other at right angles. The internal spaces formed therebetween are evacuated to maintain a vacuum.

In order to maintain a constant distance between the first substrate 20 and the second substrate 22, the spacers 38 are arranged in a predetermined interval between the first substrate 20 and the second substrate 22. do. The spacer 38 is preferably provided to avoid the position of the pixel and the path of the electron beam.

In addition, the spacer 38 also plays a role of supporting the grid plate 40 installed between the first substrate 20 and the second substrate 22.

One embodiment of the field emission display according to the present invention is a distance between the first substrate 20 and the second substrate 22 held by the spacer 38 as shown in FIGS. 1 and 2. The cell gap G is set to a predetermined range.

The cell gap refers to a gap between the cathode electrode 26 formed on the first substrate 20 and the anode electrode 32 formed on the second substrate 22 and mainly on the anode electrode 32. The spacing is determined by the strength of the applied voltage.                     

Since a voltage of several to several tens of kV is applied to the anode electrode 32 formed on the second substrate 22, the cell gap G is set in a range of approximately 1 to 5 mm. At this time, a voltage of approximately tens of volts is applied to the grid plate 40.

Preferably, a voltage of 4 to 10 kV is applied to the anode electrode 32, and the cell gap G is set in a range of about 1 to 2 mm.

If the cell gap G is set too large as compared with the intensity of the voltage applied to the anode electrode 32, the luminance is lowered since the electron beam does not collide with the fluorescent film so as to accelerate sufficiently. In addition, if the cell gap G is set too small compared with the strength of the voltage applied to the anode electrode 32, the electric field due to the voltage applied to the anode electrode 32 affects the cathode electrode 26 and the emitter 28. Electron beam is emitted from the unwanted emitter 28 and causes light emission, and the voltage applied to the anode electrode 28 is leaked or discharged toward the gate electrode 24 and / or the cathode electrode 26. The risk of damaging the gate electrode 24 and the cathode electrode 26 is greatly increased.

Therefore, for example, when applying a voltage of 4 kV to the anode electrode 32, the cell gap G is set in a range of about 1 to 1.2 mm, and a voltage of 10 kV is applied to the anode electrode 32. In this case, the cell gap G is set in a range of approximately 1.5 to 2 mm.

According to an embodiment of the field emission display device according to the present invention, the distance A between the grid plate 40 and the anode electrode 32 is set in the range of about 85 to 95% of the cell gap G. The gap B between the grid plate 40 and the cathode electrode 26 is set in the range of approximately 5 to 15% of the cell gap G.

When the cell gap G is set in the range of 1 to 5 mm, the distance A between the grid plate 40 and the anode electrode 32 is set in the range of 0.85 to 4.75 mm, preferably 0.9. Set within the range of ˜4.5 mm. The distance B between the grid plate 40 and the cathode electrode 26 is set in the range of 0.05 to 0.75 mm, preferably in the range of 0.1 to 0.5 mm.

When the cell gap G is set within the range of 1 to 2 mm, the distance A between the grid plate 40 and the anode electrode 32 is set within the range of 0.85 to 1.9 mm, and the grid plate ( The distance B between the 40 and the cathode electrode 26 is set in the range of 0.05 to 0.3 mm.

In the above, when the distance A between the grid plate 40 and the anode electrode 32 is too small, electron emission may occur at the emitter 28 which is not desired due to diode emission, which may cause the emission of other colors. high. In addition, when the distance A between the grid plate 40 and the anode electrode 32 is too large, the acceleration force of the electron beam passing through the grid plate 40 is lowered, and the beam spreading at the upper end of the grid plate 40 becomes severe. As the beam spreads on the upper end of the grid plate 40 in this manner, the electron beam collides with an undesired phosphor, and the other color emission and color purity decrease.

In addition, when the distance B between the grid plate 40 and the cathode electrode 26 is too small, a short circuit may occur between the cathode electrode 26 and the grid plate 40, which causes the cathode electrode 26. May cause damage. In addition, if the distance B between the grid plate 40 and the cathode electrode 26 is too large, the acceleration force of the electron beam before passing through the grid plate 40 is reduced, resulting in severe beam spreading at the bottom of the grid plate 40. Lose. When the beam spreads at the lower end of the grid plate 40 in this manner, the electron beam passes through another beam passing hole 42 adjacent to the other phosphors to generate other colors and deteriorate color purity.

The cell gap G according to the present invention set in the above range, the gap A between the grid plate 40 and the anode electrode 32, and the gap B between the grid plate 40 and the cathode electrode 26. ) Is a computer simulation of the emission and propagation path of the electron beam, and each value is set in various combinations and repeated experiments are obtained to obtain the most desirable range.

Next, an operation process of the field emission display device according to the present invention configured as described above will be described.

First, a predetermined voltage is applied to the gate electrode 24, the cathode electrode 26, the grid plate 40, and the anode electrode 32 from the outside. At this time, the voltage applied to each electrode is, for example, a positive voltage of several to several tens of volts to the gate electrode 24, a negative voltage of several to several tens of volts to the cathode electrode 26, and a grid plate 40. Positive voltages of several tens to hundreds of volts and anode electrodes 32 are set to positive voltages of several hundreds to thousands of volts.

When a voltage is applied to each electrode as described above, an electric field is formed around the emitter 28 due to the voltage difference between the gate electrode 24 and the cathode electrode 26, and electrons are emitted from the emitter 28. The electrons are led by the positive voltage applied to the grid plate 40 to the second substrate 22 and pass through the beam through hole 42 of the grid plate 40 and then to the anode electrode 32. A predetermined image is realized by being driven by the applied high voltage to emit light by colliding with the fluorescent film 34 of the pixel.

In the above, a preferred embodiment of the field emission display device according to the present invention has been described. However, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims, the detailed description of the invention, and the accompanying drawings. This also belongs to the scope of the present invention.

According to the field emission display device according to the present invention as described above, it is possible to set the cell gap to an appropriate size in accordance with the strength of the voltage applied to the anode electrode, it is possible to prevent the short circuit caused by the electrons emitted While maintaining a sufficient acceleration of the electron beam emitted from the emitter, it is possible to obtain an improvement in luminance, and it is possible to prevent other color emission as the emitted electron beam passes through an adjacent beam passing hole.

In addition, according to the field emission display device according to the present invention, the distance between the grid plate and the anode electrode is properly maintained, so that the beam spreading of the electron beam passing through the beam through hole of the grid plate is reduced, resulting in different light emission by changing the path of the electron beam. And it is possible to minimize the color purity deterioration, and to maintain the acceleration of the electrons and the withstand voltage characteristics between the electrodes.

In addition, according to the field emission display device according to the present invention, since the distance between the grid plate and the cathode electrode is properly maintained, it is possible to prevent a short circuit between the cathode electrode and the grid plate and to prevent the initial electron beam emitted from the emitter. It is possible to reduce the beam spreading phenomena to minimize passing through other beam through holes, resulting in light emission.

Claims (4)

A first substrate and a second substrate facing each other at a predetermined interval; A gate electrode and a cathode electrode formed in a pattern intersecting each other with an insulating layer interposed therebetween on the first substrate; An emitter formed over the cathode electrode of the portion intersecting the gate electrode; An anode electrode formed on the second substrate; A fluorescent film formed on one surface of the anode in a predetermined pattern; And A grid plate installed between the first substrate and the second substrate and formed with a plurality of beam through holes arranged in a predetermined pattern. Including, The interval between the grid plate and the anode electrode is set in the range of 85 to 95% of the cell gap; And a distance between the grid plate and the cathode electrode in a range of 5 to 15% of a cell gap. The method according to claim 1, The cell gap means a gap between a cathode electrode and an anode electrode and is set in the range of 1 to 2 mm according to the intensity of the voltage applied to the anode electrode. The method according to claim 2, And a distance between the grid plate and the anode electrode in a range of 0.85 to 1.9 mm. The method according to claim 2 or 3, And a distance between the grid plate and the cathode electrode in a range of 0.05 to 0.3 mm.

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