KR20030050571A - Field emission display - Google Patents

Abstract

PURPOSE: A field emission display device is provided to obtain the desired luminance and image by preventing the distortion of the electric field caused due to the spacer. CONSTITUTION: A field emission display device comprises an upper substrate; a lower substrate opposed to the upper substrate; a spacer(64) interposed between the upper substrate and the lower substrate, and which maintains a vacuum space between the upper and lower substrates; a first electrode(66) interposed between the upper substrate and the spacer; a second electrode(68) interposed between the lower substrate and the spacer; and an insulation film(72) covering the second electrode. The insulation film has a specific resistance of 1 to 10¬15¥Øcm.

Description

Field emission display device {FIELD EMISSION DISPLAY}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a field emission display device, and more particularly, to a field emission display device capable of preventing electron beam distortion caused by a spacer.

Recently, various flat panel displays have been developed to reduce weight and volume, which are disadvantages of cathode ray tubes (CRTs). Such flat panel displays include liquid crystal displays (LCDs), field emission displays (FEDs), plasma display panels (PDPs), and electroluminescence (Electro). -Luminescence (EL). In order to improve the display quality, research and development for increasing the brightness, contrast and color purity of flat panel displays have been actively conducted.

The FED is a display device using light emission of a phosphor similar to a cathode ray tube (CRT). Accordingly, the FED is likely to be implemented as a flat panel display having low power consumption without distortion of the image while maintaining excellent characteristics of the cathode ray tube (CRT).

In general, FED is a triode, like a conventional cathode ray tube (CRT), but quantum mechanical tunnel effect by focusing the high electric field on a sharp cathode, that is, an emitter, without using a hot cathode. A cold cathode that emits electrons is used. The electrons emitted from the emitter are accelerated by the voltage applied between the anode and the cathode and collide with the phosphor film formed on the anode to emit the phosphor.

1 and 2 are a perspective view and a cross-sectional view showing a conventional field emission display device.

Referring to FIGS. 1 and 2, a conventional FED includes a spacer for maintaining a vacuum space between an upper glass substrate 2 and a lower glass substrate 8, and an upper glass substrate 2 and a lower glass substrate 8. 40 and a field emission array 32 formed on the lower glass substrate 8.

The field emission array 32 includes the cathode electrode 10 and the resistive layer 12 formed on the lower glass substrate 8, and the gate insulating layer 14 and the emitter 22 formed on the resistive layer 12. ) And a gate electrode 16 formed on the gate insulating layer 14.

The cathode electrode 10 supplies a current to the emitter 22, and the resistive layer 12 limits the overcurrent applied from the cathode electrode 10 toward the emitter 22, thereby making it uniform to the emitter 22. It serves to supply current.

The gate insulating layer 14 insulates between the cathode electrode 10 and the gate electrode 16. The gate electrode 16 is used as an extraction electrode for drawing electrons. The spacer 40 supports the upper glass substrate 2 and the lower glass substrate 8 so as to maintain a high vacuum state between the upper glass substrate 2 and the lower glass substrate 8.

In order to display an image, a negative (-) cathode voltage is applied to the cathode electrode 10 and a positive (+) anode voltage is applied to the anode electrode 4. The gate voltage of positive polarity (+) is applied to the gate electrode 16. Then, the electron beam 30 emitted from the emitter 22 collides with the red, green, and blue phosphors 6 to excite the phosphors 6. At this time, visible light of any one of red, green, and blue colors is emitted according to the phosphor 6.

Meanwhile, a focusing electrode 20 for focusing the electron beam 30 is formed on the gate electrode 16 as shown in FIG. 3. A focusing insulating layer 18 is formed between the focusing electrode 20 and the gate electrode 16. A negative focus voltage is applied to the focusing electrode 20 to focus the electron beam 30 on the target phosphor 6. The focusing insulating layer 18 insulates the focusing electrode 20 and the gate electrode 16.

Meanwhile, in the conventional FED operating as described above, the spacer 40 is charged by diffusion of the electron beam 30. In other words, the spacer 40 is usually formed of an insulator, and the spacer 40 collided with the electron beam 30 is positively charged because the secondary electron emission coefficient of the insulator is larger than "1". When the spacer 40 is charged, the electric field around the spacer 40 is distorted, so that the desired luminance or image may not be displayed.

In order to prevent such charging of the spacer 40, a method of forming an electrode in the spacer 56 is proposed as shown in FIG. 4.

Referring to FIG. 4, the first electrode 50 is formed between the upper glass substrate 2 and the spacer 56, and the second electrode 52 is formed between the lower glass substrate 8 and the spacer 56. ), And the conductive thin film 54 is formed between the first electrode 50 and the second electrode 52.

The first electrode 50 is electrically connected to the anode electrode 4. Therefore, a high voltage is applied to the first electrode 50 like the anode electrode 4. The ground potential is supplied to the second electrode 52.

For example, when a voltage of 8 Kv is applied to the anode electrode 4, the lower glass substrate 8 is separated from the upper glass substrate 2 in the vacuum space between the upper glass substrate 2 and the lower glass substrate 8 as shown in FIG. 5. Gradually lower voltage is applied. At this time, the same voltage as that of the vacuum space is applied to the spacer 56. Therefore, the spacer 56 and the vacuum space have the same potential, thereby preventing the spacer 56 from being charged.

Meanwhile, a plurality of metal bands may be formed between the first electrode 50 and the second electrode 52 instead of the conductive thin film 54. As such, even when the metal strip is formed, it is possible to prevent the spacer 56 from being charged.

However, in the conventional spacer 56, the second electrode 52 forms a triple point where an insulator (spacer), a vacuum (vacuum space), and a metal (second electrode) meet. As such, when the triple point is formed, the electric field is concentrated on the second electrode 52. Accordingly, unwanted electrons are emitted from the second electrode 52 where the electric field is concentrated, and the emitted electrons charge the spacer 56. Accordingly, in the conventional FED, the electric field is distorted, so that the desired luminance or image cannot be displayed.

Accordingly, an object of the present invention is to provide a field emission display device capable of preventing electron beam distortion caused by a spacer.

1 is a perspective view showing a conventional field emission display device.

2 is a cross-sectional view showing a conventional field emission display device.

3 is a cross-sectional view showing a conventional field emission display device in which a focusing electrode is formed.

4 shows a conventional spacer;

5 is a diagram illustrating a voltage applied to a vacuum space when a voltage is applied.

6 to 7 are views showing a spacer according to an embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

2: upper glass substrate 4: anode electrode

6: phosphor 8: lower glass substrate

10 cathode electrode 12 resistive layer

14 gate insulating layer 16 gate electrode

18: focusing insulating layer 20: focusing electrode

22 emitter 30 electron beam

32: field emission array 40, 56, 64: spacer

50, 52, 66, 68: electrode 54, 70: conductive thin film

72: insulating film

In order to achieve the above object, the field emission display device according to the present invention includes an upper substrate, a lower substrate formed to face the upper substrate, a first electrode provided between the upper substrate and the spacer, and a lower substrate and the spacer. A second electrode and an insulating film formed to surround the second electrode.

The resistivity of the insulating film is set to 1 to 10 ¹⁵ Pa.

An anode electrode formed on the upper substrate, and a high voltage supply for supplying a high voltage to the anode electrode.

The high voltage is supplied to the first electrode.

A ground voltage is supplied to the second electrode.

Other objects and features of the present invention in addition to the above objects will become apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 6 to 8.

6 and 7 illustrate a spacer according to an embodiment of the present invention.

6 and 7, the spacer 64 according to the embodiment of the present invention is installed between the upper glass substrate 60 and the lower glass substrate 62 to allow the upper glass substrate 60 and the lower glass substrate 62. Maintain a vacuum space between

An anode electrode, a phosphor, and the like, which are not shown, are formed on the upper glass substrate 60. A cathode electrode, an emitter, and the like are formed on the lower glass substrate 62. Electrodes formed on the upper glass substrate 60 and the lower glass substrate 62 are installed in the same manner as the prior art of the present application.

The spacer 64 according to the embodiment of the present invention is provided between the first electrode 66 installed between the upper glass substrate 60 and the spacer 64, and the lower glass substrate 62 and the spacer 64. A conductive thin film 70 formed of a thin film between the second electrode 68, the first electrode 66, and the second electrode 68, and an insulating film 72 formed to cover the second electrode 68. Equipped. Here, a plurality of metal bands may be formed between the first electrode 66 and the second electrode 68 instead of the conductive thin film 70.

The high voltage applied to the anode electrode 4 is supplied to the first electrode 66. The ground potential is supplied to the second electrode 68. The conductive thin film 70 is induced with a voltage between the high voltage and the base voltage.

For example, when a voltage of 8 Kv is applied to the anode electrode 66, the vacuum space between the upper glass substrate 60 and the lower glass substrate 62 gradually increases from the upper glass substrate 60 to the lower glass substrate 62. Low voltage is applied. At this time, the same voltage as that of the vacuum space is applied to the conductive thin film 70 of the spacer 64. Therefore, the spacer 64 and the vacuum space have the same potential, and thus the spacer 64 is not charged.

In addition, the insulating layer 72 formed to surround the second electrode 68 prevents electrons from being emitted from the second electrode 68. Such an insulating film 68 has a specific resistance of 1 to 10 ¹⁵ dBm. In other words, the insulating film 68 prevents electrons from being emitted from the second electrode 68 to prevent the spacer 64 from being charged. In addition, the power consumption may be reduced by preventing the electrons from being emitted from the second electrode 68.

As described above, the field emission display device according to the present invention can prevent electrons from being emitted from the electrode by an insulating film formed to surround the electrode formed between the spacer and the lower glass substrate. As such, since the electrons are prevented from being emitted from the electrons, the spacers can be prevented from being charged. Therefore, distortion of the electric field caused by the spacer can be prevented, and thus desired luminance and image can be displayed.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (5)

A field emission display device comprising a spacer, Upper substrate, A lower substrate formed to face the upper substrate; A first electrode disposed between the upper substrate and the spacer; A second electrode disposed between the lower substrate and the spacer; And an insulating film formed to surround the second electrode. The method of claim 1, The resistivity of the insulating film is set to 1 to 10 ¹⁵ Ωcm Field emission display device, characterized in that. The method of claim 1, An anode electrode formed on the upper substrate; And a high voltage supply unit for supplying a high voltage to the anode electrode. The method of claim 4, wherein And the high voltage is supplied to the first electrode. The method of claim 1, A field emission display device comprising a ground voltage supplied to the second electrode.