JPH0950760A - Electron source base plate, image forming device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device, which can obtain the image of high quality with the arrangement of picture elements at a high density, by using an electron source base plate, in which the generation of short-circuiting of an element electrode is prevented at the time of wiring to improve the reliability of an electrical connection part. SOLUTION: Element electrodes 11, 12 are formed on a board, which is previously washed, by printing or the like. The wiring 13 of a first layer is formed by the thick film printing, and furthermore, a layer-to-layer insulating film 14 of the first layer is formed so as to cross the wiring 13. A layer-to-layer insulating film 15 of a second layer 15 is formed on the layer-to-layer insulating film 14 of the first layer so as to secure the insulating performance. The wiring 16 of a second layer is formed in an area between two ladder-shaped Y-directional patterns of the layer-to-layer insulating film 14 of the first layer through the layer-to-layer insulating film 15 of the second layer. Furthermore, connection of an element electrode 11 and the wiring 16 thereof is performed at the same time with the forming of the wiring 16 of the second layer. Finally, a film 17 of an electron emitting part is formed, and an electron emitting element for electron source is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron source and its application to an image forming apparatus such as a display device.

[0002]

2. Description of the Related Art Conventionally, two types of electron emitting devices, a thermionic electron source and a cold cathode electron source, are known. Cold cathode electron sources include field emission type (hereinafter referred to as FE), metal / insulating layer / metal type (hereinafter referred to as MIM), and surface conduction type electron emitting devices.

An example of the FE type is reported by Dyke et al. (W.
P. Dyke and WW Dolan, "Field emission", Advance
in Electron Physics, 8, 89 (1956)), S
Report of pindt (CA Spindt, "Physical Properties of
thin-film field emission cathodes with molybdeniu
m cones ", J. Appl. Phys., 47, 5248 (1976)) and the like are known.

As an example of the MIM type, a report by Mead (C.
A. Mead, "The tunnel-emission amplifier", J. Appl.
Phys., 32, 646 (1961)) and the like are known.

As an example of the surface conduction electron-emitting device, a report by Elinson (MI Elinson, Radio Eng. Electron
Phys., 10 (1965)).

[0006] The surface conduction electron-emitting device utilizes the phenomenon that electron emission occurs when a current flows through a small-area thin film formed on a substrate in parallel with the film surface.

As the surface conduction electron-emitting device, one using the SnO ₂ thin film described in the above-mentioned Erinson report, one using an Au thin film (G. Dittmer, "Thin Solid Fil") is used.
ms ", 9,317 (1972)), In ₂ O ₃ / SnO ₂ thin film (M. Hartwell and CG Fonstad," IEEE Trans. ED
Conf. ", 519 (1975)), carbon thin films (Araki et al., Vacuum, Vol. 26, No. 1, p. 22 (1983)) and the like.

FIG. 5 shows the structure of the Hartwell device described above as a typical device structure of these surface conduction electron-emitting devices. In the figure, 1 is a substrate. Reference numeral 2 denotes a thin film for forming an electron emitting portion, which is made of an H-shaped metal oxide thin film formed by sputtering or the like, and the electron emitting portion 3 is formed by an energization process called energization forming described later. The element electrode spacing L1 in the figure is
0.5-1.0 mm, W'is set to 0.1 mm. Since the position and shape of the electron emitting portion 3 are unknown, it is shown as a schematic diagram.

Conventionally, in these surface conduction electron-emitting devices, it is general that the electron-emitting portion forming thin film 2 is formed with the electron-emitting portion 3 in advance by an energization process called forming before the electron emission. It was That is, the energization forming means that a direct current voltage or a very slow rising voltage, for example, about 1 V / min is applied to both ends of the electron emission portion forming thin film 2 to energize the thin film 2 to locally break, deform or deform the conductive thin film. This is to form the electron-emitting portion 3 which has been altered so as to have an electrically high resistance state. In the electron emitting portion 3, a crack is generated in a part of the electron emitting portion forming thin film 2, and electrons are emitted from the vicinity of the crack. Hereinafter, the thin film for forming an electron emitting portion including the electron emitting portion generated by forming will be referred to as a thin film including an electron emitting portion (4 in the figure). The surface conduction electron-emitting device that has been subjected to the forming treatment,
A voltage is applied to the thin film 4 including the electron emitting portion described above, and a current is caused to flow on the surface of the device, so that electrons are emitted from the electron emitting portion 3 described above.

Furthermore, a step called "activation" is usually introduced after the forming step is completed. The purpose is to increase the amount of electron emission by continuously applying a constant voltage to the surface conduction electron-emitting device whose resistance has been increased by forming for a constant time.

The surface conduction electron-emitting device described above has an advantage that a large number of it can be arrayed over a large area because it has a simple structure and is easy to manufacture. Therefore, various applications have been studied to make full use of this feature. For example,
Examples of applications include a charged beam source and a display device such as an image forming device.

A screen printing method may be used to form the wiring and the insulating film. This is a method in which a conductive paste or an insulating paste is directly pattern-printed through a screen and then baked to form an electrode wiring pattern or an insulating film. The patterning by this printing method can be applied to a large area substrate. The processing time per substrate is shorter than that of the photolithography technique, and the cost can be reduced.

[0013]

However, there are the following problems in increasing the area of the surface conduction electron-emitting device as described above as an image forming apparatus.

Since the printing pattern is easily deformed due to the fluidity and transferability of the resist ink, the conductive paste and the insulating paste by using the above printing method, the dimensional accuracy of the pattern is low. Therefore, in some cases, a short circuit with the device electrode occurs due to the positional deviation or sagging of the second layer wiring pattern. Further, for this reason, a defect may occur in the image forming apparatus.

Therefore, the present invention has been made to solve the above-mentioned problems, and an object thereof is to reduce a short circuit with an element electrode at the time of forming a wiring in the formation of an electron source substrate, thereby reducing electric power consumption. It is intended to improve the reliability of the electronically connected portion so that an image forming apparatus using the electron source substrate can obtain a high-quality image by a higher-density pixel array.

[0016]

According to the present invention, a plurality of electron-emitting devices including a pair of device electrodes are provided on a substrate, and a plurality of first-layer wirings and a plurality of second-layer wirings which are orthogonal to each other with an insulating layer interposed therebetween are provided. In a method of manufacturing an electron source substrate arranged at positions where wiring intersects, 1) a step of forming a plurality of element electrode pairs on the substrate, 2) a step of forming a wiring of a first layer, 3) the first layer Connecting the wiring of FIG. 3 and one of the element electrodes (first element electrode) of the element electrode pair, 4) Except for the portion (connecting portion) of the band-shaped insulating layer that intersects with the wiring of the first layer and its vicinity A step of forming an insulating layer having an opening in the central portion thereof at a position where the wiring of the second layer is formed, 5) A wiring of a second layer having a width equal to or smaller than the width of the insulating layer is formed on the strip-shaped insulating layer. Step of forming, 6) the wiring of the second layer and the device electrode (second device) facing the first device electrode. Device electrode), and 7) a step of forming an electron-emitting device based on the device electrode pair, and a method of manufacturing an electron source substrate, and an electron source substrate manufactured by the method. Furthermore, a step of facing the electron source substrate and a substrate having an area where an image is formed and bonding them via a support frame, a step of reducing the pressure between the two substrates, Provided are a method of manufacturing an image forming apparatus including a step of connecting a drive circuit for image formation, and an image forming apparatus manufactured by the method.

[0017]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a typical device structure of an electron source substrate manufactured by the method of the present invention.

FIG. 2 shows the procedure of the method of manufacturing the electron source substrate of the present invention. In FIG. 2, an example is shown in which a total of 9 electron-emitting devices (3 × 3) are formed on a substrate (not shown) together with wiring in a matrix. In the figure, 11 and 12 are a pair of device electrodes, 13 is a first layer wiring, 14 is a first layer interlayer insulating film, 15 is a second layer interlayer insulating film, 16 is a second layer wiring, and 17 is It is a thin film for forming an electron emitting portion.

The method of manufacturing the electron source substrate of the present invention will be described in detail below with reference to FIG.

First, element electrodes are printed and baked on a previously washed substrate to form element electrode pairs consisting of the element electrodes 11 and 12 (FIG. 2A). This electrode is provided to improve the ohmic contact between the electron emission thin film and the wiring. In general, the electron-emitting portion thin film is a film that is extremely thin as compared with the conductor layer for wiring, and thus has "wetness",
This is provided in order to avoid problems such as “step-holding property”. Therefore, when the conductor layer for wiring is formed of a thin film by a sputtering method or the like, the electron emission portion thin film does not necessarily have to be formed separately, but can be formed simultaneously with the wiring conductor.

As a method for forming the electrodes, a method using a vacuum system such as a vacuum vapor deposition method, a sputtering method, a plasma CVD method or the like is formed by printing and firing a thick film paste in which a metal component and a glass component are mixed with a catalyst. There is a thick film printing method.

In the manufacturing method of the present invention, the shortening of the process is most remarkable when the thick film printing method which does not require the photolithography process is used. However, it is desirable that the electrode near the electron emitting portion has a small film thickness. Therefore, when the thick film printing method is used, it is preferable to use an MOD paste containing an organometallic compound as the paste used at that time. Of course, any other film forming method may be used, and the constituent material is not particularly limited as long as it is an electrically conductive material.

Next, the first layer wiring 13 is formed (FIG. 2).
(B)). The wiring can be formed by applying the same method as the formation of the device electrodes 11 and 12, but in the case of wiring, unlike the electrode portion, a thicker film can reduce the electric resistance. Is advantageous. Therefore, it is advantageous to use the thick film printing method. As a matter of course, thin film wiring can be applied, but it is disadvantageous because it takes time to increase the film thickness.

Next, a strip-shaped first layer interlayer insulating film 14 is formed (FIG. 2C). This interlayer insulating film is shown in FIG.
Pattern in the X direction at the intersection with the first layer wiring as described above (because it is necessary to completely cover the first layer wiring at the intersection,
It is a ladder shape composed of two patterns in the Y direction connected to each other at the intersection and the vicinity thereof. The insulating film may be made of a material that can maintain the insulating property. Examples thereof include a SiO ₂ thin film and a film made of a thick film paste containing no metal component.

Next, the second-layer interlayer insulating film 15 is formed on the first-layer interlayer insulating film to ensure insulation (FIG. 2 (d)).

Next, the second layer wiring 16 is formed (see FIG. 2).
(E)). At this time, the wiring 16 is formed in the region between the two ladder-shaped Y-direction patterns of the first interlayer insulating layer 14 with the second interlayer insulating film 15 interposed therebetween. Further, the device electrode 11 and the wiring 16 are connected at the same time when the wiring 16 of the second layer is formed. The formation method is
The same method as that for the wiring of the first layer can be applied. In this way, the second Y-direction pattern of the first-layer insulating film
By providing the wiring of the layer, the insulating layer plays a role of a bank to prevent a short circuit with the element electrode due to a sag when the wiring of the second layer is formed. Further, according to such a method, the second
Since the wiring and the element electrode are connected at the same time when the wiring of the layer is formed, it is not necessary to provide a connection pattern,
The number of steps can be reduced.

Finally, the film 17 of the electron-emitting portion is formed, and the electron-emitting device for the electron source (3 × 3 = 9 in total) is completed (FIG. 2 (f)). As the film forming method and the electron emitting portion (surface conduction electron emitting device) forming method, the conventional method can be applied as it is (described later).

Although only the 9-element portion is shown in this figure,
By forming a plurality of these at the same time, an electron source having a simple matrix structure can be manufactured.

The present invention provides an excellent effect in a simple matrix type image forming apparatus using surface conduction electron-emitting devices among the image forming apparatuses, and an image forming apparatus using a thick film printing method. Which has an excellent effect in the production method of.

The basic structure of the surface conduction electron-emitting device according to the present invention, its manufacturing method and its features (for example, refer to JP-A-2-56822) will be outlined below.

In the surface conduction electron-emitting device according to the present invention, 1) a thin film for forming an electron-emitting portion before energization treatment called forming is a thin film composed of fine particles formed by dispersing a fine particle dispersion, or an organic metal. And the like, which is basically composed of fine particles, such as a thin film made of fine particles formed by heating and baking the above, and 2) a thin film including an electron emission portion after energization treatment called forming includes an electron emission portion and an electron emission portion. The thin film is basically composed of fine particles.

FIGS. 6 (a) and 6 (b) are a plan view and a sectional view, respectively, showing the structure of a basic surface conduction electron-emitting device according to the present invention. The basic structure of the element according to the present invention will be described with reference to FIG. 6. In the electron source and the image forming apparatus of the present invention, as will be described later, a large number of surface conduction electron-emitting devices are provided on the same substrate. It is formed together with the wiring electrode.

In FIG. 6, 1 is an insulating substrate, 5 and 6 are device electrodes, 4 is a thin film including an electron emitting portion, and 3 is an electron emitting portion.

As the insulating substrate 1, quartz glass, Na
Examples thereof include glass having a reduced content of impurities such as glass, soda lime glass, a glass substrate having a soda lime glass laminated with SiO ₂ (insulator layer) formed by a sputtering method, and ceramics such as alumina.

As the material of the device electrodes 5 and 6 which face each other, a general electric conductor is used. For example, Ni, Cr, A
u, Mo, W, Pt, Ti, Al, Cu, Pd, Ag,
Metals such as Ru, Ta, Pb, Zr, Hf, Sb and La,
Or alloys of these metals, as well as Pd, Ag, A
A printed conductor composed of a metal or metal oxide such as u, RuO ₂ , Pd-Ag or the like and glass, In ₂ O ₃ —SnO ₂
And transparent semiconductors and semiconductor materials such as polysilicon.

The element electrode spacing L1 is several Å to several hundreds of μm, and is based on the photolithography technology that is the basis of the method of manufacturing the element electrodes, that is, the performance and etching method of the exposure device, the voltage applied between the element electrodes, and the like. Although it is set depending on the electric field strength capable of emitting electrons, etc., it is preferably several μm to several tens μm. Device electrode length W1, film thickness of device electrodes 5 and 6 d
Is appropriately designed according to the resistance value of the electrode, the connection with X and Y wirings described later, and the layout of a large number of electron sources. Normally, the element electrode length W1 is several μm to several hundred μm. And
The film thickness d of the device electrodes 5 and 6 is several hundred Å to several thousand Å.

The thin film 4 including the electron-emitting portion provided between the opposing element electrode pairs 5 and 6 provided on the insulating substrate 1 and on the element electrode pair 5.6 includes the electron-emitting portion 3, Not only the case shown in FIG. 7 (b), but it may not be provided on the device electrodes 5 and 6. That is, there may be a case where the above-described thin film for forming an electron emission portion and the opposing element electrode pair 5 and 6 are laminated in this order on the insulating substrate 1. In addition, depending on the manufacturing method, the entire space between the opposing device electrode pairs 5 and 6 may function as an electron emitting portion. The film thickness of the thin film 4 including the electron emitting portion is several Å to several thousand Å, and the step coverage to the element electrodes 5 and 6, the resistance value between the electron emitting portion 3 and the element electrodes 5 and 6, and the electron emitting portion. It is appropriately set depending on the particle diameter of the conductive fine particles of No. 3, the energization processing conditions described later, and the like. The resistance value is 10 ³ to 10 ⁷ Ω /
The sheet resistance value of □ is shown.

Materials for forming the thin film 4 including the electron emitting portion include Pd, Pt, Ru, Ag, Au, Ti, In,
Metals such as Cu, Cr, Fe, Zn, Sn, Ta, W and Pb; oxides such as PdO, SnO ₂ , In ₂ O ₃ , PbO and Sb ₂ O ₃ ; HfB ₂ , ZrB ₂ , LaB ₆ , CeB. ₆ , YB
₄ , boride such as GdB ₄ ; TiC, ZrC, HfC, Ta
Carbides such as C, SiC, WC; TiN, ZrN, HfN
And the like; semiconductors such as Si and Ge; carbon and the like.

The fine particle film described here is a film in which a plurality of fine particles are aggregated, and its fine structure is not only in the state where the fine particles are individually dispersed and arranged but also in the state where the fine particles are adjacent to each other or overlap each other (island). (Including the shape), and the particle size of the fine particles is several Å to several thousand Å, preferably 10 Å to 200 Å.

The electron emitting portion 3 is a high resistance crack formed in a part of the thin film 4 including the electron emitting portion, and is formed by energization forming or the like. Also, several Å to several hundred Å in the crack
In some cases, the conductive fine particles having the particle size of The conductive fine particles contain at least a part of the elements that constitute the thin film 4 including the electron emitting portion. Further, the thin film 4 including the electron emitting portion 3 and the electron emitting portion in the vicinity thereof may have carbon or a carbon compound.

Various methods are conceivable as a method of manufacturing the electron-emitting device having the electron-emitting portion 3, one example of which is shown in FIG. Reference numeral 2 is a thin film for forming an electron emitting portion, and for example, a fine particle film can be mentioned.

Hereinafter, the method of manufacturing this element will be described step by step with reference to FIGS. 6 and 7.

1) After the insulating substrate 1 is thoroughly washed with a detergent, pure water and an organic solvent, element electrode materials are deposited by a vacuum deposition method, a sputtering method or the like, and then the surface of the insulating substrate 1 is formed by a photolithography technique. Device electrodes 5 and 6 on top
Is formed (FIG. 7A).

2) An organic metal thin film is formed by applying an organic metal solution between the device electrodes 5 and 6 provided on the insulating substrate 1 and leaving it to stand. The organometallic solution referred to here means Pd, Ru, Ag, Au, Ti, In,
It is a solution of an organic compound whose constituent elements are metals such as Cu, Cr, Fe, Zn, Sn, Ta, W, and Pb. After this,
The organometallic thin film is heat-fired and patterned by lift-off, etching, etc. to form the electron-emitting portion forming thin film 2 (FIG. 7B).

Although the organic metal coating method has been described here, the present invention is not limited to this, and a vacuum deposition method, a sputtering method, a chemical vapor deposition method, a dispersion coating method, a dipping method, a spinner method, or the like is used. It may be done.

3) Subsequently, energization processing called forming is performed. The energization forming is performed by energizing the device electrodes 5 and 6 with a power source (not shown) to form the electron emission portion forming thin film 2
Is locally destroyed, deformed or altered to form a site with a changed structure. The part where the structure is locally changed is called an electron emitting part 3 (FIG. 7C).
As described above, the present inventor has observed that the electron emitting portion 3 is composed of conductive fine particles.

Next, 1 of the voltage waveform of the forming process is performed.
An example is shown in FIG.

The voltage waveform is preferably a pulse shape, and the voltage pulse having a constant pulse peak value is continuously applied (FIG. 8A) and the voltage pulse is applied while increasing the pulse peak value (FIG. 8A). 8 (b)). First,
A case where the pulse crest value is a constant voltage (FIG. 8A) will be described.

In FIG. 8A, T1 and T2 are the pulse width and pulse interval of the voltage waveform, and T1 is 1 μsec to 10 μs.
Millisecond, T2 is set to 10 μsec to 100 msec, the peak value of the triangular wave (peak voltage during energization forming) is appropriately selected according to the form of the surface conduction electron-emitting device, and a suitable vacuum degree, for example, 1 × 10. ^In a vacuum atmosphere of about ^-5 Torr,
Apply for several seconds to several tens of minutes. The waveform applied between the electrodes of the element is not limited to the triangular wave, and a desired waveform such as a rectangular wave may be used. Further, the crest value, the pulse width, the pulse interval, etc. are not limited to the above values, and a desired value can be selected as long as the electron emitting portion is formed well.

T1 and T2 in FIG.
Similar to the case of (a), the peak value of the triangular wave (peak voltage during energization forming) is increased by, for example, about 0.1 V step and applied in an appropriate vacuum atmosphere.

In the energization forming process in this case, the device current is set to a voltage that does not locally break or deform the electron emission portion forming thin film 2 during the pulse interval T2, for example, a voltage of about 0.1V. The resistance value is measured, and the energization forming is completed when the resistance value is, for example, 1 MΩ or more.

Next, it is desirable to perform a process called an activation process on the element for which the energization forming has been completed.

The activation step is, for example, 10 ^-4 to 10 ^-5.
Similar to the energization forming, it is a process of repeatedly applying a voltage pulse having a constant pulse peak value at a vacuum degree of about Torr. Carbon or a carbon compound derived from an organic substance existing in a vacuum is deposited on a thin film to form an element. This is a process of remarkably changing the current If and the emission current Ie. In the activation process, while measuring the device current If and the emission current Ie, for example,
The process ends when the emission current Ie is saturated. Further, it is preferable that the applied voltage pulse is an operation drive voltage.

Here, carbon or carbon compound means graphite (refers to both single crystal and polycrystal) and amorphous carbon (refers to a mixture of amorphous carbon and polycrystal graphite). Film thickness is 50
It is preferably 0 Å or less, more preferably 300 Å or less.

The electron-emitting device thus manufactured is preferably operated and driven in an atmosphere having a vacuum degree higher than the vacuum degree in the energization forming step and the activation step. Also, in an atmosphere with a higher degree of vacuum, 80 ° C to 150 ° C
It is desirable to drive after heating.

The vacuum degree higher than the vacuum degree obtained by the energization forming process and the activation treatment means, for example, about 10 ⁻⁶ Tor.
The degree of vacuum is equal to or higher than r, more preferably an ultrahigh vacuum system, and the degree of vacuum is such that new carbon or carbon compound is hardly deposited on the conductive thin film. By doing this,
It is possible to stabilize the device current If and the emission current Ie.

Next, the basic characteristics of the electron-emitting device according to the present invention produced by the above-described device structure and manufacturing method will be described with reference to FIGS. 9 and 10.

FIG. 9 is a schematic block diagram of a measurement / evaluation apparatus for measuring electron emission characteristics of an element having the structure shown in FIG. In FIG. 9, 1 is an insulating substrate, 5 and 6 are device electrodes, 4 is a thin film including an electron emitting portion, and 3 is an electron emitting portion. Further, 91 is a power supply for applying a device voltage Vf to the device, 90 is an ammeter for measuring a device current If flowing through the thin film 4 including the electron emitting portion between the device electrodes 5 and 6, and
94 is an anode electrode for capturing the emission current Ie emitted from the electron emission portion of the device, and 93 is an anode electrode 94.
A high voltage power supply for applying a voltage to the device, and an ammeter 92 for measuring an emission current Ie emitted from the electron emitting portion 3 of the device. To measure the device current If and the emission current Ie of the electron-emitting device, a power supply 91 and an ammeter 90 are connected to the device electrodes 5 and 6, and a high-voltage power supply 93 and an ammeter 92 are connected above the electron-emitting device. The connected anode electrode 94 is arranged. Further, the present electron-emitting device and the anode electrode 94 are arranged in a vacuum device, and the vacuum device is equipped with equipment necessary for the vacuum device such as an exhaust pump and a vacuum gauge. The measurement and evaluation of can be performed. The voltage of the anode electrode was 1 to 10 kV, and the distance H between the anode electrode and the electron-emitting device was 3 to 8 mm.

FIG. 10 shows a typical example of the relationship between the emission current Ie and the device current If and the device voltage Vf measured by the measurement / evaluation apparatus shown in FIG. Note that FIG. 10 is shown in arbitrary units, and the emission current Ie is about 1 of the device current If.
It is about 1/000. As is clear from the figure, this electron-emitting device has three characteristics with respect to the emission current Ie.

First, in this device, when a device voltage higher than a certain voltage (called threshold voltage, Vth in FIG. 10) is applied, the emission current Ie rapidly increases. On the other hand, at a voltage lower than the threshold voltage, the emission current Ie is hardly detected.
That is, it is a non-linear element having a clear threshold voltage Vth with respect to the emission current Ie.

Secondly, since the emission current Ie depends on the element voltage Vf, the emission current Ie can be controlled by the element voltage Vf.

Thirdly, the amount of charge trapped in the anode electrode 94 can be controlled by the time for which the device voltage Vf is applied.

Since the electron-emitting device according to the present invention has the above characteristics, it is expected to be applied to the other surface.
Further, FIG. 10 shows an example of the (M1) characteristic that the element current If monotonously increases with respect to the element voltage Vf.
In some cases, the device current If exhibits a voltage control type negative resistance (VCNR) characteristic with respect to the device voltage Vf. Also in this case, the electron-emitting device has the above-mentioned three characteristics. A surface conduction electron-emitting device having conductive fine particles dispersed therein can be manufactured by partially modifying the basic manufacturing method of the basic device structure of the present invention.

Next, the electron source and the image forming apparatus of the present invention will be described.

The electron source substrate used in the image forming apparatus is formed by arranging a plurality of surface conduction electron-emitting devices on the substrate. The surface conduction electron-emitting devices are arranged in a ladder-type arrangement in which the surface conduction electron-emitting devices are arranged in parallel and each end of each device is connected by wiring, or a pair of surface-conduction electron-emitting device electrodes. X direction wiring, Y respectively
A simple matrix arrangement in which directional wirings are connected (hereinafter referred to as a matrix-type arrangement electron source substrate) can be mentioned. The present invention relates to a matrix-type arrangement electron source substrate.

The structure of the electron source substrate constructed based on this principle will be described below with reference to FIG. 111 is an insulating substrate, 112 is X-direction wiring, 113 is Y-direction wiring,
114 is a surface conduction electron-emitting device, and 115 is a connection. In the figure, the insulating substrate 111 is the above-mentioned glass or the like, and the size and thickness of the insulating substrate 111 are the number of surface conduction electron-emitting devices and the design shape of each device, and the container when the electron source is used. Part of the
It is appropriately set depending on the conditions for holding the container in vacuum. The m X-direction wirings 112 are Dx1, Dx2.
..Dxm, which is made of a conductive metal or the like patterned in a predetermined shape on the insulating substrate 111, and is made of a material and a film so that a substantially uniform voltage is supplied to a large number of surface conduction electron-emitting devices. Thickness, wiring width, etc. are set. The Y-direction wiring 113 is composed of n wirings Dy1, Dy2, ... Dyn, and is made of a conductive metal or the like patterned into a predetermined shape like the X-direction wiring 112, and has a large number of surface conduction electron-emitting devices. The material, the film thickness, the wiring width, and the like are set so that a substantially uniform voltage is supplied to.

These m X-direction wirings 112 and n Y-wirings
An interlayer insulating layer (not shown) is provided between the direction wirings 113 and electrically separated to form a matrix wiring.
Note that both m and n are positive integers. The interlayer insulating layer (not shown) is a layer made of SiO _2, etc.
12 is formed on the entire surface or a part of the insulating substrate 111 having a predetermined shape, and the film thickness, material, and manufacturing method are appropriately selected so as to withstand the potential difference at the intersection of the X-direction wiring 112 and the Y-direction wiring 113. Is set. The X-direction wiring 112 and the Y-direction wiring 113 are drawn out as external terminals.

Here, an example in which n Y-direction wirings 113 are provided on m X-direction wirings 112 via an interlayer insulating layer has been described. Alternatively, m X-direction wirings 112 can be installed via an interlayer insulating layer.

Further, in the same manner as described above, the opposing device electrodes (not shown) of the surface conduction electron-emitting device 114 are Dx.
1, Dx2 ... Dxm m X-direction wirings 112, D
It is electrically connected to n Y-direction wirings 113 of y1, Dy2 ... Dyn by a connection 115.

Incidentally, m X-direction wirings 112 and n Y-direction wirings are provided.
The directional wiring 113, the connection 115, and the conductive metal of the device electrode may have some or all of the constituent elements that are the same or different, and Ni, Cr, Au, Mo, W, Pt, and T may be used.
Metals such as i, Al, Cu and Pd or alloys thereof; P
A printed conductor composed of a metal or metal oxide such as d, Ag, Au, RuO ₂ , Pd-Ag and glass; In ₂
It is appropriately selected from transparent conductors such as O ₃ —SnO ₂ and semiconductor materials such as polysilicon. The surface conduction electron-emitting device may be formed either on the insulating substrate 111 or on an interlayer insulating layer (not shown).

Further, a scanning signal generating means (not shown) for applying a scanning signal for arbitrarily scanning a row of the surface conduction electron-emitting devices 114 arranged in the X direction is electrically connected to the X-direction wiring 112. Connected to each other. On the other hand, a modulation signal generating means (not shown) for electrically applying a modulation signal for arbitrarily modulating each row of the surface conduction electron-emitting devices 114 arranged in the Y direction to the Y-direction wiring 113. It is connected.

Further, the drive voltage applied to each surface conduction electron-emitting device is supplied as a difference voltage between the scanning signal and the modulation signal applied to the device. In the above structure, individual elements can be selected and driven independently with simple matrix wiring.

Next, regarding the image forming apparatus using the electron source of the simple matrix arrangement manufactured as described above,
This will be described with reference to FIGS. 3 is a basic configuration diagram of the image forming apparatus, and FIG. 4 is a pattern of a fluorescent film used in the image forming apparatus.

In FIG. 3, 31 is an electron source substrate in which the electron-emitting device is formed on the substrate as described above, 34 is an electron-emitting device, and 35 and 36 are a pair of device electrodes of the surface conduction electron-emitting device. X-direction wiring and b-direction wiring connected to 32 is a rear plate to which the electron source substrate 31 is fixed, 40 is a fluorescent film 38 on the inner surface of the glass substrate 37.
And a face plate on which a metal back 39 and the like are formed,
Reference numeral 33 denotes a support frame, which is coated with frit glass or the like on the rear plate 32, the support frame 33, and the face plate 40, and is sealed and sealed by baking at 400 to 500 ° C. for 10 minutes or more in the air or nitrogen. The container 41 is configured.

The envelope 41 is composed of the face plate 40, the support frame 33, and the rear plate 32 as described above, but the rear plate 32 is provided mainly for the purpose of reinforcing the strength of the electron source substrate 31. If the electron source substrate 31 itself has sufficient strength, the separate rear plate 32 is not necessary, and the support frame 33 is directly sealed to the electron source substrate 31, and the face plate 40, the support frame 33, and the electron source. The substrate 41 may constitute the envelope 41. Furthermore, by providing an atmospheric pressure resistant support member called a spacer between the face plate 40 and the rear plate 32, the envelope 41 having sufficient strength against atmospheric pressure can be obtained.

In FIG. 3, 38 is a fluorescent film. Fluorescent film 38
In the case of monochrome, only the phosphor is used, but in the case of the color phosphor film 38, as shown in FIG. 4, a black member 42 and a phosphor 43 called a black stripe or a black matrix depending on the arrangement of the phosphor 43. Composed of and. In the case of color display, the purpose of providing the black stripes and the black matrix is to make the mixed portions between the respective phosphors 43 of the three primary color phosphors black so as to make the color mixture inconspicuous, and in the phosphor film 38. This is to suppress a decrease in contrast due to reflection of external light. The material for the black stripes is not limited to the commonly used material containing graphite as a main component, but is not limited to this material as long as the material transmits and reflects light little.

As a method for applying the phosphor 43 to the glass substrate 37, a precipitation method or a printing method is used regardless of whether it is monochrome or color.

A metal back 39 is usually provided on the inner surface of the fluorescent film 38. The purpose of the metal back 39 is
Preventing the electrons emitted to the phosphor 43 from being charged, improving the brightness by specularly reflecting the light toward the inner surface side of the light emission of the phosphor 43 to the face plate 40 side, and the electron beam accelerating voltage Is to act as an electrode for applying the, and to protect the phosphor 43 from damage due to collision of negative ions generated in the envelope. The metal back 39 is subjected to a smoothing process on the inner surface of the fluorescent film 38 after the fluorescent film 38 is formed (normally called filming).
And then depositing Al by vacuum vapor deposition or the like. The face plate 40 further has a fluorescent film 3
A transparent electrode (not shown) may be provided on the outer surface side of the fluorescent film 38 in order to enhance the conductivity of the fluorescent film 38.

At the time of performing the above-mentioned sealing, in the case of a color, it is necessary to sufficiently align the phosphors of the respective colors with the electron-emitting devices.

The envelope 41 is connected through an exhaust pipe (not shown) to
^The degree of vacuum is set to about ^-7 Torr, and sealing is performed. In addition, a getter process may be performed in order to maintain the degree of vacuum after the envelope 41 is sealed. This is done by heating the getter placed at a predetermined position (not shown) in the envelope 41 by a heating method such as resistance heating or high frequency heating immediately before or after the envelope 41 is sealed. , A process of forming a vapor deposition film. The getter usually has Ba as a main component,
Due to the adsorption action of the deposited film, for example, 1 × 10 ⁻⁵ to 1 ×
The vacuum degree of 10 ⁻⁷ Torr is maintained. In addition,
The steps after the forming of the surface conduction electron-emitting device are appropriately set.

In the image forming apparatus of the present invention manufactured as described above, each electron-emitting device has a terminal D outside the container.
Electrons are emitted by applying a voltage through x1 to Dxm and Dy1 to Dyn, and a high voltage of several kV or more is applied to the metal back 39 or the transparent electrode (not shown) through the high voltage terminal Hv to accelerate the electron beam, An image can be displayed by colliding with the fluorescent film 38 to excite and emit light.

The configuration described above is a schematic configuration necessary for producing a suitable image forming apparatus used for image display and the like, and the detailed parts such as the material of each member are not limited to the above contents. Instead, it is appropriately selected to suit the application of the image forming apparatus.

According to the present invention, it is possible to provide an image forming apparatus suitable for not only a display device for television broadcasting but also a display device such as a video conference system and a computer. Furthermore, the electron source of the present invention can be used as an image forming apparatus as an optical printer including a photosensitive drum or the like.

[0085]

EXAMPLES Examples of the present invention will be described below.

Example 1 In this example, production of an electron source substrate having a structure as shown in FIG. 1 and an image forming apparatus using the same will be described with reference to FIG. As shown in FIG. 2, in this example, the electron-emitting devices were formed on the substrate (not shown) in a matrix of 3 × 3 in total, including 3 × 3.

First, a cleaned glass substrate (here,
Soda lime glass substrate is used), and a pair of device electrodes 1
1 and 12 were formed. In this example, a thick film printing method was used as a film forming method. The thick film paste material used here is MOD paste, and the metal component is Au.

The printing method is a screen printing method. After printing, it was dried at 70 ° C. for 10 minutes and then subjected to main firing. The firing temperature is 550 ° C. and the peak holding time is about 8 minutes. The pattern after printing and firing is 350 x 150 μm,
The thickness was about 0.3 μm (FIG. 2 (a)).

Next, the wiring 13 of the first layer is connected and formed on one side of the device electrode 12. Here, as a method of forming the first layer wiring 13, a thick film screen printing method is used. The thick film paste material used was Ag paste, and the metal part was Ag.
It is. After screen printing with a predetermined pattern,
Drying at 110 ° C. for 20 minutes, baking at 550 ° C. for a peak holding time of 15 minutes, width 100 μm, thickness 12 μm
m first-layer wiring 13 was formed (FIG. 2B).

Next, a first layer interlayer insulating film 14 was formed. The interlayer insulating film 14 has a ladder shape including both patterns in the X direction and the Y direction. In this embodiment, it is formed by using the thick film screen printing method. Paste material is PdO
Is a paste containing a glass binder as a main component. The firing temperature is 550 ° C and the peak holding time is about 15
Minutes. When a binder was screen-printed in a predetermined pattern and then baked, the pattern width after baking was a ladder shape with two patterns of 500 μm in the X direction and 60 μm in the Y direction, and the thickness was about 15 μm. It was a layer. At that time, formation was performed so that the X-direction pattern of the first-layer interlayer insulating film 14 was located on the first-layer wiring 13 (FIG. 2C).

Next, a second-layer interlayer insulating film 15 was formed. Usually, the insulating layer is printed and fired twice in order to ensure insulation between the upper and lower layers. This is because the film formed by the thick film paste is usually a porous film. Therefore, after printing and firing once, printing is performed again to print and fire the second film so as to fill the porous state of the first film. This ensures the insulation. In the present embodiment, the second-layer interlayer insulating film 15 is formed only in the vicinity of the intersection of the first-layer wiring 13 requiring insulation and the second-layer wiring formed later. The forming method and the paste material were the same as those of the first layer interlayer insulating film 14, and the thick film screen printing method and the glass paste method were used. The firing temperature was 550 ° C., and the peak holding time was about 15 minutes. The pattern after screen printing and firing on a predetermined pattern had a size of 500 × 500 μm and a thickness of about 15 μm. The total thickness of the insulating layer at the intersection is about 30.
μm (FIG. 2 (d)).

Next, the second layer wiring 16 was formed. At this time, the wiring 16 is formed by forming the first interlayer insulating layer 14
Between the two ladder-shaped patterns in the Y direction via the second-layer interlayer insulating film 15 formed at the intersection of the first-layer wiring 13 and the second-layer wiring 16. Furthermore, the device electrode 11 and the wiring 16 were connected at the same time when the wiring 16 of the second layer was formed. As a forming method, a thick film screen printing method was used. The thick film paste material used is Ag paste and the metal part is Ag. After screen printing with a predetermined pattern and drying at 110 ° C for 20 minutes,
Width of 30 after baking at 550 ° C for a peak holding time of 15 minutes
A second layer wiring 16 having a thickness of 0 μm and a thickness of 10 μm was obtained (FIG. 2).
(E)).

After the completion of the matrix wiring, the electron emitting portion was formed. First, organopalladium (CCP4230; manufactured by Okuno Chemical Industries Co., Ltd.) was spin-coated on the upper layers of the device electrodes 11 and 12 for energizing the electron emission portions by the spinner by spin coating, and then at 10 ° C. at 10 ° C. The heat treatment for 1 minute was performed to form an electron emission portion forming thin film 17 made of Pd. The electron emission portion forming thin film 1 thus formed
7 is composed of fine particles containing Pd as a main element,
The film thickness was 10 nm, and the sheet resistance value was 5 × 10 ⁴ Ω / □. The fine particle film described here is a film in which a plurality of fine particles are aggregated, and the fine structure thereof is not only a state in which the fine particles are individually dispersed and arranged but also a state in which the fine particles are adjacent to each other or overlap each other (including an island shape). The membrane of
The particle diameter means the diameter of fine particles whose particle shape can be recognized in the above state.

By patterning this palladium film using the photolithography method, the element manufacturing process before forming was completed (FIG. 2 (f)).

When the electron source substrate manufactured as described above was manufactured, a short circuit with the device electrode due to sagging when forming the wiring of the second layer did not occur.

Example 2 In this example, the electron source manufactured in Example 1 was used to obtain an image forming apparatus. This will be described with reference to FIGS. 3, 4 and 8.

As shown in FIG. 3, the electron source substrate 31 having a large number of surface conduction electron-emitting devices is mounted on the rear plate 3.
After being fixed on the substrate 2, the face plate 40 (which is formed by forming the fluorescent film 38 and the metal back 39 on the inner surface of the glass substrate 37) is supported by the support frame 33 5 mm above the substrate 31.
The frit glass is applied to the joint portion of the face plate 40, the support frame 33, and the rear plate 32.
It was sealed by baking at 50 ° C. for 10 minutes (see FIG. 3). The substrate 31 was also fixed to the rear plate 32 with frit glass.

In FIG. 3, 34 is an electron-emitting device and 35
And 36 are wirings in the X and Y directions, respectively.

In the case of monochrome, the fluorescent film 38 is composed of only the fluorescent material, but in this embodiment, the fluorescent material adopts a stripe shape (see FIG. 4), and a black stripe is formed first, and each of the gaps is formed. A phosphor was applied to form a phosphor film 38. As the material for the black stripe, a material which is commonly used and whose main component is graphite was used.

The method of applying the phosphor to the glass substrate 37 was a slurry method.

A metal back 39 is usually provided on the inner surface side of the fluorescent film 38. In this example, the metal back performs a smoothing process (usually called filming) on the inner surface of the fluorescent film after the fluorescent film is produced, and then,
It was produced by vacuum deposition of Al.

The face plate 40 is further provided with a fluorescent film 3
A transparent electrode (not shown) may be provided on the outer surface side of the fluorescent film 38 in order to enhance the conductivity of No. 8, but in this embodiment, it was omitted because sufficient conductivity was obtained only by the metal back.

When performing the above-mentioned sealing, in the case of color, the phosphors of the respective colors have to correspond to the electron-emitting devices, so that sufficient alignment is performed.

The atmosphere in the glass container completed as described above is exhausted by a vacuum pump through an exhaust pipe (not shown), and after reaching a sufficient degree of vacuum, the external terminals Dx1 to Dxm
And Dy1 to Dyn, a voltage is applied between the device electrodes of the electron-emitting device 34, and the electron-emitting region forming thin film 2 is energized (forming process) to form the electron-emitting region 3. FIG. 8 shows the voltage waveform of the forming process.

In FIG. 8, T1 and T2 are the pulse width and pulse interval of the voltage waveform. In this embodiment, T1 is 1 millisecond,
T2 was 10 milliseconds, the peak value of the triangular wave (peak voltage during forming) was 14 V, and the forming treatment was carried out for 60 seconds in a vacuum atmosphere of about 1 × 10 ⁻⁶ Torr.

In the electron emitting portion 3 thus produced, fine particles containing palladium as a main component were dispersed and arranged, and the average particle diameter of the fine particles was 30Å.

Next, the exhaust pipe (not shown) is welded by heating with a gas burner at a vacuum degree of about 1 × 10 ^-6 Torr,
The envelope was sealed.

Finally, to maintain the degree of vacuum after sealing,
Getter processing was performed. The getter treatment is a heating method such as resistance heating or high-frequency heating immediately before or after sealing, and heats a getter arranged at a predetermined position (not shown) in the image forming apparatus to form a vapor deposition film. Is a process for forming. The getter usually has Ba as a main component, and due to the adsorption action of the deposited film, for example, 1 × 10 ⁻⁵ to
The vacuum degree of 1 × 10 ⁻⁷ Torr is maintained.

In the image forming apparatus of the present invention manufactured as described above, scanning signals and modulation signals (not shown) are supplied to the respective surface conduction electron-emitting devices through the terminals Dx1 to Dxm and Dy1 to Dyn outside the container. An electron is emitted by applying each by a generating means, a high voltage of 5 kV is applied to the metal back 39 through the high voltage terminal Hv, the electron beam is accelerated, collides with the fluorescent film 38, and excited and emits an image. Was displayed. As a result, a good quality image without defects was obtained.

A good electrophotographic recording apparatus can be constructed by producing an array of light emitting elements according to the method for producing an electron source substrate shown in the above embodiment and disposing it on a photosensitive drum. did it.

In addition, the same effect can be obtained when the array-shaped light emitting element is formed in the electrophotographic recording device.

[0112]

As is clear from the above description, according to the present invention, it is possible to prevent a short circuit of the element electrode during the formation of the wiring of the electron source substrate, so that when it is used in an image forming apparatus, pixel defects are reduced. Thus, a high quality image can be obtained. Furthermore, according to the method of the present invention, XY is formed on the substrate.
It is easy to arrange a large number of surface conduction electron-emitting devices in a matrix, and an electron source substrate suitable for a large-screen image forming apparatus can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing a typical element structure of an electron source substrate of the present invention.

FIG. 2 is a process drawing showing an example of the manufacturing procedure of the electron source substrate of the present invention.

FIG. 3 is a partially cutaway perspective view showing the configuration of an example of an image forming apparatus of the present invention.

FIG. 4 is a schematic partial view showing a structure of a fluorescent film,
(A) is provided with a black stripe, (b)
[Fig. 3] is a diagram of a device provided with a black matrix.

FIG. 5 is a schematic plan view showing a configuration of an example of a surface conduction electron-emitting device.

6A and 6B are schematic diagrams showing a configuration of an example of a surface conduction electron-emitting device provided in the electron source of the present invention, FIG. 6A being a plan view and FIG. 6B being a sectional view.

7A to 7C are process diagrams showing a procedure for forming the device of FIG.

FIG. 8 is a graph showing a voltage waveform during energization forming when manufacturing a surface conduction electron-emitting device in the electron source of the present invention, where (a) shows a case where the pulse crest value is constant,
(B) is a case where the pulse peak value increases.

FIG. 9 is a schematic configuration diagram of an apparatus for measuring and evaluating electron emission characteristics of a surface conduction electron-emitting device.

FIG. 10 is a diagram showing current-voltage characteristics of a surface conduction electron-emitting device.

FIG. 11 is a schematic view of an electron source substrate formed by simple matrix wiring of a large number of surface conduction electron-emitting devices.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Electron emission part forming thin film 3 Electron emission part 4 Thin film including an electron emission part 5 Element electrode 6 Element electrode 11 Element electrode 12 Element electrode 13 First layer wiring 14 First layer interlayer insulation layer 15th Two-layer interlayer insulating film 16 Second layer wiring 17 Electron emitting portion forming thin film 31 Electron source substrate 32 Rear plate 33 Support frame 34 Electron emitting device 35 X direction wiring 36 Y direction wiring 37 Glass substrate 38 Fluorescent film 39 Metal back 40 Face Plate 41 Envelope 42 Black Member 43 Phosphor 90 Ammeter 91 Power Supply 92 Ammeter 93 High Voltage Power Supply 94 Anode Electrode 111 Insulating Substrate 112 X Direction Wiring 113 Y Direction Wiring 114 Surface Conduction Electron Emitting Element

Claims (10)

[Claims] 1. A plurality of electron-emitting devices including a pair of device electrodes are arranged on a substrate at positions where a plurality of first-layer wirings and a plurality of second-layer wirings intersect each other with an insulating layer interposed therebetween. In the method of manufacturing an electron source substrate, the steps of: 1) forming a plurality of device electrode pairs on the substrate; 2) forming a first layer wiring; 3) forming a wiring of the first layer and the device electrode pair Step of connecting one element electrode (first element electrode), 4) A strip-shaped insulating layer is opened at a portion (coupling portion) intersecting with the wiring of the first layer and a central portion other than the vicinity thereof. Forming an insulating layer at a position where a second layer wiring is formed, 5) forming a second layer wiring having a width equal to or smaller than the width of the insulating layer on the strip-shaped insulating layer, 6) the above A process for connecting the two-layer wiring and an element electrode (second element electrode) facing the first element electrode. (7) A method of manufacturing an electron source substrate, including the step of 7) forming an electron-emitting device based on the device electrode pair. 2. The manufacturing method according to claim 1, further comprising forming an insulating layer on the connecting portion of the insulating layer after forming the band-shaped insulating layer. 3. The manufacturing method according to claim 1, wherein the wiring of the first layer and the first element electrode are connected simultaneously with the formation of the wiring. 4. The manufacturing method according to claim 1, wherein the wiring of the second layer and the second element electrode are connected simultaneously with the formation of the wiring. 5. The strip-shaped insulating layer is formed so that one end of the second element electrode is located in each opening of the strip-shaped insulating layer, and then the wiring of the second layer is formed. The manufacturing method described. 6. A conductive thin film is formed between the pair of elements, and an electron emitting portion is formed on a part of the thin film by an electric current treatment.
The manufacturing method according to claim 1, wherein a surface conduction electron-emitting device is formed as the electron-emitting device. 7. The printing method is used to form each of the layers.
7. The method for manufacturing an electron source substrate according to any one of 6 to 6. 8. An electron source substrate manufactured by the method according to claim 1. 9. A step of making an electron source substrate manufactured by the method according to claim 1 and a substrate having an area where an image is formed face each other, and joining them via a support frame, A method of manufacturing an image forming apparatus, comprising: a step of reducing the pressure between the two substrates; and a step of connecting a drive circuit for image formation to the electron source substrate. 10. An image forming apparatus manufactured by the method according to claim 9.