JPH1116523A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device in which no leak current is carried in the part of a sealant even when a high voltage is applied to an anode electrode by enclosing an anode drawing electrode in the sealant position with an insulating material so as not to make contact directly with the sealant. SOLUTION: An anode drawing electrode 21 is enclosed by a glass tube 20 so as not to make contact directly with a sealant 7 welded to an anode substrate 1 or a cathode substrate 2. The connection of the anode drawing electrode 21 to an anode electrode 15 is performed, for example, by nipping the tip of the anode drawing electrode 21 by the anode substrate 1 and the glass tube 20, and this nipping force is caused by the atmospheric pressure. Although an anode voltage of, for example, 2-5 kV is applied to the anode drawing electrode 21, no leak current is carried in the part of the sealant 7 since this electrode 21 does not make contact with the sealant 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device having a field emission cathode, and more particularly to a display device for applying a high voltage to an anode electrode.

[0002]

2. Description of the Related Art FIG. 9 shows an example of a sectional view of a display device having a conventional field emission cathode. The display device shown in FIG. 9 is a full-color display device. For example, a large number of striped anode electrodes 106 are formed on the inner surface of the anode substrate 101. Phosphors for emitting R, G, and B light are sequentially deposited on the anode electrode 106. An FEC array 105 composed of a number of field emission cathodes (FECs) is provided on the cathode substrate 102.
Are formed. Electrons are field-emitted from the FEC array 105, and the emitted electrons are captured by the anode electrode 106, so that the phosphor adhered to the captured anode electrode 106 emits light. You.

[0003] Here, the field emission will be briefly described. The applied voltage on the surface of a metal or semiconductor is 10 ⁹ [V /
m], the electrons pass through the barrier due to the tunnel effect, and the electrons are emitted in a vacuum even at room temperature. This is called field emission, and a cathode that emits electrons based on such a principle is called a field emission cathode or a field emission element.

In recent years, it has become possible to manufacture a surface emission type field emission cathode composed of a field emission cathode of a micron size by making full use of semiconductor fine processing technology. A large number of field emission cathodes are formed on a substrate. The FEC array described above can be used as an electron supply unit that constitutes a flat display device or various electronic devices by irradiating electrons emitted from each emitter to a phosphor screen. As an example of such a field emission cathode, a field emission cathode called a Spindt type (hereinafter, referred to as a Spindt type).
"FEC") is known.

Returning to FIG. 9, the control of the electrons emitted from the cathode substrate 102 is generally performed in the FEC array 105, and the electrons emitted from the FEC array 105 are separated from each other by the support 104 at a predetermined interval. It flies toward the opposed anode substrate 101. In order to enable such an operation, a space formed between the anode substrate 101 and the cathode substrate 102 has a vacuum atmosphere. In order to maintain a vacuum atmosphere, the peripheral portions of the anode substrate 101 and the cathode substrate 102 are sealed with a sealing material 103.

The interval t between the anode substrate 101 and the cathode substrate 102 is, for example, several hundred μm. In this case, an anode voltage of several hundred V is applied to the anode electrode 106. The anode electrode 106 is connected to a display control device located outside the display device by an anode extraction electrode (not shown), and an anode voltage is applied at a predetermined timing by the display control device. Further, the cathode electrode and the gate electrode in the FEC array 105 are also connected to a display control device located outside the display device by a cathode extraction electrode or a gate extraction electrode (not shown), and the display control device controls the cathode voltage or the gate voltage at a predetermined timing. Has been applied.

[0007]

By the way, as a phosphor to be attached to the anode electrode 106, a phosphor having high luminous efficiency for a low voltage of several hundred volts has not been developed at present. Therefore, as a phosphor for high voltage of several thousand V,
Since a phosphor having good luminance characteristics is present, it is conceivable to apply a high voltage of several thousands V to the anode electrode as one of means for making a display device with high luminance. In this case, the anode voltage is applied to the anode electrode by the anode extraction electrode extracted through the sealing material.

[0008] However, although the sealing material is mainly composed of glass, it has a characteristic that its insulation resistance is low due to a composition mixed therein to reduce the melting point. Then, when a high voltage is applied to the anode extraction electrode drawn out through the sealing material, the leakage current flows through the sealing material between the cathode electrode or the gate electrode drawn out through the sealing material. This causes a problem that the display device may not function properly.

Further, in order to apply a high voltage between the anode electrode and the cathode electrode, it is necessary to increase the distance between the anode electrode and the cathode electrode. Then, since the divergence angle of the electrons emitted from the cathode electrode is set to about 30 degrees, the electrons reach the anode electrode in a state where the electrons are diffused. There is a problem that light emission may occur.

Accordingly, an object of the present invention is to provide a display device in which a leakage current does not flow in a sealing material portion even when a high voltage is applied to an anode electrode.
Still another object of the present invention is to provide a display device in which electrons reaching the anode electrode are not diffused even when a high voltage is applied to the anode electrode.

[0011]

In order to achieve the above object, a display device of the present invention comprises a cathode substrate on which a field emission cathode for emitting electrons in a field is formed, and an electron emitted from the cathode substrate. An anode substrate on which an anode electrode on which a phosphor to be captured is formed is disposed; and the anode substrate and the cathode substrate are arranged so that a distance between the anode substrate and the cathode substrate is a predetermined distance. A supporting member, a sealing material for sealing peripheral edges of the anode substrate and the cathode substrate so that a space formed by the anode substrate and the cathode substrate maintains a vacuum atmosphere, and a sealing material interposed therebetween. An anode extraction electrode connected to the anode electrode, which is extracted from a space formed by the anode substrate and the cathode substrate. The anode extraction electrode at the position of the sealing material is covered with an insulating material so as not to directly contact the sealing material.

In the above display device, a focusing electrode made of a metal plate is provided on the insulating thin film formed on the field emission cathode. Furthermore,
The insulating material surrounding the anode extraction electrode is glass.

According to the present invention, since the anode extraction electrode does not directly come into contact with the sealing material having poor insulation properties, even if a high voltage is applied to the anode electrode via the anode extraction electrode, the sealing material is not used. The leakage current can be prevented from flowing in the portion. Therefore, a phosphor having good emission characteristics can be used, and a display device with high luminance can be obtained. Further, since the focusing electrode is provided, even if the distance between the anode electrode and the cathode electrode is increased, the spread of the electrons emitted from the cathode electrode can be suppressed. Therefore, a high-definition display device capable of preventing leakage light emission can be provided.

[0014]

FIG. 1 is a sectional view showing the structure of a display device according to an embodiment of the present invention. FIG. 1 is a view showing a part of a cross section of a display device according to the present invention. A transparent anode substrate 1 made of, for example, glass and an insulating cathode substrate 2 made of, for example, glass are separated by a predetermined distance. And are arranged facing each other. The inner surface of the anode substrate 1 has R
A large number of anode electrodes 15 on which (red), G (green), and B (blue) phosphors are sequentially applied are formed.
One pixel is formed by one set of G and B. A large number of field emission cathode (FEC) arrays 6 are formed on the inner surface of the cathode substrate 2. Note that the FEC array 6 is formed so as to face the anode electrode 15 on which each phosphor is adhered.

A focusing electrode 5 is provided on the FEC array 6 via an insulating layer so as to focus an electron beam emitted from the FEC array 6. Furthermore, since the space formed by the anode substrate 1 and the cathode substrate 2 is a vacuum atmosphere, the anode substrate 1
A large number of columns 4 are provided between the anode substrate 1 and the cathode substrate 2 so that the anode substrate 1 and the cathode substrate 2 maintain a predetermined distance over the entire surface against atmospheric pressure. The support 4 is made by cutting a glass fiber material having a diameter of 75 μm, for example, into a length of about 1.2 mm, and is provided for each of pixels of R, G, and B, for example. The distance between the anode substrate 1 and the cathode substrate 2 is, for example, approximately 1.2 mm.

Further, an anode substrate 1 and a cathode substrate 2
The anode extraction electrode 21 connected to the anode electrode 15 is extracted to the outside at the position of the peripheral edge portion sealing the above. At this time, the anode extraction electrode 21
It is covered by a glass tube 20 described later. Therefore, the anode extraction electrode 21 does not come into direct contact with the sealing material 7 that is welding the glass tube 20 to the anode substrate 1 or the cathode substrate 2. The connection between the anode extraction electrode 21 and the anode electrode 15 is made by, for example, clamping the tip of the anode extraction electrode 21 by the anode substrate 1 and the glass tube 20, and this clamping force is generated by the atmospheric pressure. ing. An anode voltage of, for example, 2 kV to 5 kV is applied to the anode extraction electrode 21, but since the anode extraction electrode 21 is not in contact with the seal member 7, no leakage current flows in the seal member 7. .

FIG. 2 shows a detailed configuration of the cathode substrate 2 in such a display device. FIG. 2 is an enlarged sectional view showing a part of the cathode substrate. As shown in FIG. 2, a large number of FEC arrays 6 are formed on the cathode substrate 2, and the FEC arrays 6 are composed of Spindt-type field emission cathodes. The Spindt-type field emission cathode includes a cathode electrode 8 formed on the cathode substrate 2.
And a thin film of the first insulating layer 12 and a thin film of the gate electrode 13 are sequentially formed on the cathode electrode 8. A conical emitter cone 11 is formed in an opening formed in the gate electrode 13 and the first insulating layer 12, and a tip portion of the emitter cone 11 faces from the opening of the gate electrode 13. Note that a resistance layer may be formed on the cathode electrode 8, and the emitter cone 11 may be formed on the resistance layer. According to this configuration, the emitter cone 11
Electrons can be stably emitted from the substrate.

The field emission cathode (FEC)
Are manufactured by using a microfabrication technique for manufacturing an integrated circuit, and the emitter cone 11 and the gate electrode 1 are formed.
3 can be manufactured with a submicron distance, so that electrons can be emitted from the emitter cone 11 by applying a voltage of only several tens of volts between the emitter cone 11 and the gate electrode 13. Therefore,
As shown in FIG. 1, an anode substrate 1 on which a fluorescent material is applied is disposed above a cathode substrate 2 on which a large number of FECs are formed in an array, and a space between the gate electrode 13 and the emitter cone 11 is provided. When the voltages V _GE and _VA are applied to the anode electrode 15, the fluorescent material on the anode electrode 15 can emit light by the electrons emitted from the emitter cone 11.

Further, in the display device of the present invention, the second insulating layer 14 is formed on the gate electrode 13, and the focusing electrode 5 is provided on the second insulating layer 14. Since the focusing electrode 5 is disposed so as to surround the FEC array 6, when a predetermined level of voltage is applied to the focusing electrode 5, electrons (e ⁻ ) emitted from the FEC array 6 are shown in FIG. Can be focused. The focusing electrode 5 is formed by etching or punching a thin metal plate having a thickness of, for example, 30 μm or more, as described later. Note that the column 4 is erected on the focusing electrode 5.

As described above, in the display device of the present invention, since the distance between the anode electrode 15 and the cathode electrode 8 is about 1.2 mm, the anode voltage is 2 kV to 5 kV.
High voltage. For this reason, as the phosphor adhered to the anode electrode 15, a phosphor for high voltage with good emission characteristics can be used. Therefore,
The brightness of the display device can be improved. Note that even if a high voltage is applied to the anode electrode 15, the anode extraction electrode 21 does not directly contact the sealing material 7, which has poor insulation properties, so that leakage current can be prevented from flowing in that portion. . In addition, since the focusing electrode 15 is provided even if the distance between the anode electrode 15 and the cathode electrode 8 is increased to about 1.2 mm, which is larger than the conventional distance, electrons emitted from the FEC array 6 can be focused. . Accordingly, since the spread of electrons when the electrons reach the anode electrode 15 can be suppressed, the pixel pitch can be reduced, and a high-definition display device can be obtained.

Next, the structure of the focusing electrode plate 10 forming the focusing electrode 5 is shown in FIGS. FIG. 3A is a plan view of the focusing electrode plate 10. The focusing electrode plate 10 made of a metal plate has a large number of rectangular holes 10-1 formed by etching or punching. The hole 10-1 is formed so as to be aligned with the FEC array 6 described above. That is, the hole 10-1 is formed in pixel units, and the focusing electrode plate 1 around the hole 10-1 is formed.
With 0, the focusing electrode 5 is formed. An extraction electrode 10-2 for applying a focusing voltage is formed on a side edge of the focusing electrode plate 10.

FIG. 3B is an enlarged view of the portion A shown in FIG. 3A. The hole 10-1 is formed corresponding to the R, G, and B pixels. The width t3 of 10-1 is approximately 60 μm, the horizontal interval t4 between the holes 10-1 is also approximately 60 μm, and the vertical interval t2 between the holes 10-1 is approximately 5
0 μm, and the vertical pitch t5 of the hole 10-1 is approximately 0.3.
1 mm, a trio pitch t1 with R, G, and B as a set,
It is approximately 0.31 mm. This gives 0.28x
0.26 × 0.0 corresponding to a pixel pitch of 0.08 mm
An electron emission range (area of the hole 10-1) of about 6 mm can be obtained. Further, the focusing electrode 5 is indicated by hatching as shown in the figure.

Next, a method of enclosing the anode extraction electrode 21 with the glass tube 20 will be described with reference to FIGS. As shown in FIGS. 4A and 4B, the through hole 2
0-1 formed through-hole 2 in glass tube 20
A wire serving as the anode extraction electrode 21 is inserted into 0-1. Then, the distal end of the wire is bent as shown.
In this state, as shown in FIGS. 5 (a) and 5 (b), the through hole 20-1 is crushed and brought into close contact by performing heat molding on the whole. By forming in this manner, the anode extraction electrode 21 is connected to the glass tube 20.
Will be wrapped. And in this state, it is arrange | positioned at the peripheral part so that the anode board | substrate 1 and the cathode board | substrate 2 may hold. Then, by heating to seal the cathode substrate 2 and the anode substrate 1,
The two substrates 1 and 2 are welded by a sealing material applied to the peripheral portions. This state is shown in FIG. The length of the glass tube 20 is approximately 2.5 mm to 3.0 mm.
Degree.

Next, a manufacturing process flow chart of the display device of the present invention is shown in FIGS.
First, as shown in FIG. 6A, a conductive thin film is formed on one surface of the anode substrate 1, and an anode electrode 15 is formed by patterning the thin film. Further, R, G, and B phosphors are applied to the anode electrode 15. Next, as shown in FIG. 6B, the plurality of columns 4 are erected on one surface of the anode substrate 1. Further, as shown in FIG. 6C, a glass tube 20 in which the sealing material 7 is applied to the periphery of the anode substrate 1 and the anode extraction electrode 21 is inserted substantially in the center is disposed.

On the other hand, an FEC array 6 is formed on one surface of the cathode substrate 2 as shown in FIG. Next, as shown in FIG. 6E, the focusing electrode plate 10 is positioned and temporarily fixed on the FEC array 6. As a result, the focusing electrode 5 is formed on the FEC array 6. Next, the anode substrate 1 and the cathode substrate 2 are aligned and adhered to each other, housed in a heating furnace and heated to seal the anode substrate 1 and the cathode substrate 2 together. The display device thus sealed is shown in FIG.

Next, the display device 1 manufactured as described above is described.
An example of the appearance of 00 is shown in FIGS. FIG.
FIG. 8 is a plan view of the display device 100, and FIG. 8 is a view showing a cross section cut along the line AA. As shown in these figures, a structure for exhaust is provided on the outer surface of the cathode substrate 2. This configuration includes a getter box 24 and an exhaust pipe 25 welded to the getter box 24. Further, a getter 27 is housed in the getter box 24, and the getter box 24 is welded to the cathode substrate 2 by a sealing member 28 at the time of sealing.

The exhaust pipe 25 is connected to the anode substrate 1 and the cathode substrate 2 through an exhaust hole 26 formed in the cathode substrate 2.
And the space formed by the exhaust pipe 2 after sealing.
By evacuating through the space 5, the inside space of the display device 100 is set to a vacuum atmosphere. Further, the getter 27 housed in the getter box 24 is an evaporable getter using a Ba-Al alloy housed in a ring-shaped metal member as a getter material. Then, the ring-shaped portion is induction-heated by a high frequency from the outside, so that Ba is obtained.
-The Al alloy is heated and evaporated, and the getter box 24
Is deposited on the inner wall surface. This deposited film is called a getter mirror because it looks like a mirror.

The getter mirror is formed by evaporating the getter 27 after sealing the exhaust pipe 25, so that the getter mirror can maintain a vacuum atmosphere inside the display device 100.
Further, as shown in the figure, the anode substrate 1 and the cathode substrate 2 may be sealed with a side plate 3 interposed between the peripheral portions of the anode substrate 1 and the cathode substrate 2. The anode extraction electrode 21 and the cathode extraction electrode 22 are also extracted from the periphery of the anode substrate 1 and the cathode substrate 2 by the above-described method.

[0029]

Since the present invention is constructed as described above, the anode lead-out electrode does not directly come into contact with the sealing material having poor insulation properties, so that a high voltage is applied to the anode electrode through the anode lead-out electrode. Even if the voltage is applied, it is possible to prevent the leakage current from flowing in the sealing material. Therefore, a phosphor having good emission characteristics can be used, and a display device with high luminance can be obtained. Further, since the focusing electrode is provided, even if the distance between the anode electrode and the cathode electrode is increased, the spread of the electrons emitted from the cathode electrode can be suppressed. Accordingly, since leakage light emission can be prevented, the pixel pitch can be reduced, and a high-definition display device can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an embodiment of a display device of the present invention.

FIG. 2 is a partially enlarged view of the display device of the present invention shown in FIG.

FIG. 3 is a diagram showing a configuration of a focusing electrode according to the display device of the present invention.

FIG. 4 is a diagram showing a configuration of an anode extraction electrode according to the display device of the present invention.

FIG. 5 is a diagram showing a configuration of an anode extraction electrode according to the display device of the present invention.

FIG. 6 is a diagram showing a manufacturing process flow of the display device of the present invention.

FIG. 7 is a plan view showing the entire configuration of the display device of the present invention.

FIG. 8 is a cross-sectional view showing the entire configuration of the display device of the present invention.

FIG. 9 is a cross-sectional view illustrating a configuration example of a conventional display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode substrate 2 Cathode substrate 4 Post 5 Focusing electrode 6 FEC array 7 Sealing material 8 Cathode electrode 10 Focusing electrode plate 11 Emitter cone 12 First insulating layer 13 Gate electrode 14 Second insulating layer 20 Glass tube 21 Anode extraction electrode 22 Cathode extraction Electrode 100 Display

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihiko Hirata 629 Oshiba, Mobara-shi, Chiba Futaba Electronics Co., Ltd. (72) Inventor Takeshi Tonegawa 629 Oshiba, Mobara-shi, Chiba Futaba Electronics Co., Ltd.

Claims (3)

[Claims] 1. A cathode substrate on which a field emission cathode for field emission of electrons is formed; and a device for capturing electrons emitted from the cathode substrate;
An anode substrate on which an anode electrode on which a phosphor is adhered is formed; and an anode substrate and the cathode substrate are disposed between the anode substrate and the cathode substrate such that a distance between the anode substrate and the cathode substrate is a predetermined interval. A support member, a sealing material for sealing peripheral portions of the anode substrate and the cathode substrate so that a space formed by the anode substrate and the cathode substrate maintains a vacuum atmosphere, An anode extraction electrode that is drawn from a space formed by the anode substrate and the cathode substrate and that is connected to the anode electrode, and at least comprises: A display device, wherein an anode extraction electrode is covered with an insulating material. 2. The display device according to claim 1, wherein a focusing electrode made of a metal plate is disposed on the insulating thin film formed on the field emission cathode. 3. The display device according to claim 1, wherein the insulating material surrounding the anode extraction electrode is made of glass.