JPH0935627A - Electron source board, its manufacture, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability of mutually and electrically connecting parts and realize a high quality picture image, by equipping complementary insulation layers for preventing element electrodes standing opposite to each other from electrically contacting with one of scan-side wiring and signal-side wiring. SOLUTION: The numerals 10, 11 denoting element electrodes, 12 a first wiring layer, 13 a second wiring layer, these wiring layers 12, 13 constitute simple matrix wiring structured in the X-direction and in the Y-direction on an insulating substrate 1. Complementary insulation layers 14 are formed to run across and cover one end side of element electrodes 10, 11 and the first wiring layer 12, preventing the first wiring layer 12 and the element electrode 11 from contacting with the second wiring layer 13. Interlayer insulation layers 15, which are formed between respective element electrodes and cover partly the complementary insulation layers 14, separate electrically the first wiring layer 12 and the second wiring layer 13 from each other in the direction normal to a surface of the insulating substrate 1. The numeral 16 denotes a thin film for forming an electron emitting part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron source substrate and an image forming apparatus such as a display device which is an application thereof.
In particular, the present invention relates to an electron source substrate having a large number of surface conduction electron-emitting devices, an image forming apparatus such as a display device incorporating the same, and a manufacturing method thereof.

[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. The cold cathode electron source includes a field emission type (hereinafter, referred to as FE), a metal / insulating layer / metal type (hereinafter, referred to as MIM), a surface conduction type electron emission element, and the like.

As an example of the FE type, WPDyke & WWDol
an, “Field emission”, Advancein Electron Physici
s, 8, 89 (1956) or CASpindt, “Physical Proper
ties of thin-film field emission cathodes with mol
ybdenium ", J. Appl. Phys., 47, 5248 (1976).

As an example of the MIM type, CAMead, “The
tunnel-emission amplifier, J. Appl. Phys., 32, 646
(1961) is known.

As an example of the surface conduction electron-emitting device, M.
I. Elinson, Radio Eng. Electron Phys., 10, (1965)]
Etc.

The surface conduction electron-emitting device utilizes a phenomenon in which electron emission occurs when a current is passed through a thin film having a small area formed on a substrate in parallel with the film surface. Examples of the surface conduction electron-emitting device include a device using a SnO ₂ thin film by Elinson et al., And a device using an Au thin film [G.
Dittmer: “Thin Solid Films”, 9, 317 (1972)], In ₂
O ₃ / SnO ₂ thin film [M.Hartwell and CG
Fonstad: “IEEE Trans. ED Conf.”, 519 (1975)], a carbon thin film [Hisashi Araki et al .: Vacuum, Vol. 26, No. 1, page 22 (1983)] and the like are reported.

As a typical device structure of these surface conduction electron-emitting devices, the device structure of M. Hartwell described above is shown in FIG.
Shown in 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 and the like, and the electron emitting portion 3 is formed by an energization process called forming described later. The element electrode spacing L1 in the figure is 0.5 to 1.0 mm,
W 'is set at 0.1 mm. Further, since the position and shape of the electron emitting portion 3 are unknown, they are shown as a schematic diagram.

Conventionally, in these surface conduction electron-emitting devices, the electron-emitting portion forming thin film 2 is formed before electron emission.
In general, the electron-emitting portion 3 was formed by previously performing an energization process called forming. 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, and the conductive thin film is locally destroyed or deformed. Alternatively, it is to form the electron emitting portion 3 which is made to have a high electrical resistance by being altered. 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 is referred to as a thin film 4 including an electron emitting portion.

In the surface-conduction type electron-emitting device which has been subjected to the forming treatment, a voltage is applied to the thin film 4 including the above-mentioned electron-emitting portion, and a current is caused to flow along the surface of the device, so that the electron-emitting portion 3 causes the electrons to be emitted. Is to be released.

Furthermore, a step called "activation" is usually introduced after the forming step is completed. The purpose of this 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.

Since the surface conduction electron-emitting device described above has a simple structure and is easy to manufacture, it has an advantage that a large number of devices can be arrayed over a large area. Therefore, various applications that can make full use of this feature are being researched. For example, a charged beam source, a display device such as an image forming device, or the like can be used.

[0012]

However, in order to increase the area of an image forming apparatus by arranging a large number of surface conduction electron-emitting devices as described above, there are the following problems. When processing an electrode or a wiring pattern in the manufacturing process of the surface conduction electron-emitting device, a metal thin film of the electrode and the wiring material is formed on the substrate, and the pattern is processed using ordinary photolithography and etching techniques. Electrodes and wiring patterns are formed. However, for example, when an electron-emitting device is manufactured on a large-sized substrate of 40 cm square or more by photolithography and etching techniques, a large-scale manufacturing facility including a vapor deposition apparatus, an exposure apparatus, an etching apparatus, etc. is required, which is enormous. In addition to the large cost, it is difficult to increase the size of the manufacturing apparatus itself when the size of the substrate is increased, which causes a problem in terms of the manufacturing method or cost. In addition, the increase in the number of electrodes due to the large area,
There is a problem that the number of steps increases, the number of processes increases, defects such as disconnection and short circuit are likely to occur, and the yield decreases, because of increase in wiring and complication. In view of such a conventional problem, the present invention is an inexpensive method for manufacturing an electron source substrate and an image forming apparatus in which a plurality of surface conduction electron-emitting devices are installed.
By reducing the number of steps and simplifying the configuration of the electrode and wiring parts, the reliability of mutual electrical connection parts can be improved, and high-quality images can be realized by a higher-density pixel array. An object of the present invention is to provide an electron source substrate on which a plurality of type electron-emitting devices are installed, a manufacturing method thereof, and an image forming apparatus.

[0013]

In order to solve the above problems, the present invention provides an electron-emitting device having device electrodes facing each other at a position where a scanning side wiring and a signal side wiring are orthogonal to each other, and the wiring is provided. One set or a plurality of sets are sequentially selected, and a plurality of electron-emitting devices that are energized to the electron-emitting devices are arranged on the substrate. To provide an electron source substrate characterized by comprising a complementary insulating layer for preventing electrical contact between a device electrode and one of the wirings, wherein the complementary insulating layer has at least one end side of both device electrodes facing each other, and The electron-emitting device is formed so as to cover one of the wirings, and the electron-emitting device is formed by subjecting the electron-emitting-device forming thin film to an energization process. Comprising a surface conduction electron-emitting device.

According to the present invention, in the above-mentioned method for manufacturing an electron source substrate, one insulating layer of the interlayer insulating layer separating the scanning side wiring and the signal side wiring and the complementary insulating layer is replaced with the other insulating layer. The method for manufacturing an electron source substrate is characterized in that the electron source substrate is formed after the formation of.

Further, the present invention is the above-mentioned method for manufacturing an electron source substrate, characterized in that a thick film printing method is used for forming wirings, insulating layers, or electrodes.

Further, the present invention has at least the above-mentioned electron source substrate and a pixel made of a phosphor which emits visible light upon irradiation with an electron beam and is arranged so as to face each electron-emitting device of the electron source substrate. The image forming apparatus.

Furthermore, the present invention is an image forming apparatus characterized by incorporating the above-mentioned electron source substrate.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, in a wiring structure of a simple matrix structure having a scanning side wiring and a signal side wiring, by providing a complementary insulating layer for preventing the wiring from coming into contact with electrodes, 1 ． The insulation between the scanning side wiring and the signal side wiring and the reliability of the device electrodes and contacts are improved. 2. The tolerance for misalignment of the upper wiring (scanning side or signal side) with respect to the interlayer insulating layer is expanded. 3. Since the short circuit between the device electrodes due to the upper wiring (scanning side or signal side) can be reduced, the high-density electron-emitting devices can be arranged.

With the above effects, it is possible to reduce the manufacturing cost by improving reliability and yield, and it becomes possible to display a high-definition image when applied to an image forming apparatus.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a typical configuration example of the electron source substrate of the present invention. Further, FIG. 12 shows an example of a flow chart of the manufacturing process of the electron source substrate of the present invention. In the figure, 10 and 11 are element electrodes, 12 is a first wiring layer, 13 is a second wiring layer, and these wiring layers 12 and 13 form a simple matrix configuration on the insulating substrate 1 in the X and Y directions. The wiring is configured. Reference numeral 14 denotes a complementary insulating layer, which is formed so as to cover one end sides of the device electrodes 10 and 11 and the first wiring layer 12 so as to cover the first wiring layer 12, the device electrode 11 and the second wiring layer 13. Prevents contact with. Reference numeral 15 is an interlayer insulating layer formed between the device electrodes 10 so as to partially cover the complementary insulating layer 14, and electrically connects the first wiring layer 12 and the second wiring layer 13 in a direction perpendicular to the substrate surface. Separated. Reference numeral 16 is a thin film for forming an electron emitting portion.

A method of manufacturing the electron-emitting device and the electron source substrate will be described below with reference to the process chart of FIG.

First, the device electrodes 10 and 11 are formed on the previously washed insulating substrate 1 (FIG. 12A). These electrodes 10 and 11 are provided in order to improve ohmic contact between a thin film including an electron emitting portion described later and the wiring layers 12 and 13. Usually, the thin film including the electron-emitting portion is a film that is significantly thinner than the conductor layers 12 and 13 for wiring, and therefore is provided in order to avoid problems such as "wetting property" and "step-holding property". Is. When the conductor layer for wiring is formed of a thin film by, for example, a sputtering method, it is not always necessary to provide and it can be formed at the same time as the wiring conductor.

As a method of forming the electrodes 10 and 11, a method using a vacuum system such as a vacuum vapor deposition method, a sputtering method, a plasma CVD method, or a thick film paste in which a solvent is mixed with a metal component and a glass component is printed and fired. There is a thick film printing method that is formed by such a method. As a method for maximizing the effect of the present invention, there is a thick film printing method which does not require a photolithography process, and the use of this method can shorten the process most. However, it is desirable that the electrode near the electron emitting portion has a small film thickness. Therefore, as the paste used when using the thick film printing method, it is preferable to use a so-called MOD paste composed of an organometallic compound. Of course, other film formation methods may be used, and the constituent materials are not particularly limited as long as they are electrically conductive materials. Further, in the case of constituting the simplest process of the present invention, an electrode in the vicinity of the electron emitting portion, and an electrode for connection with an external circuit (not shown)
It is possible to form the parts and at the same time. Also in this case, it is easy to use the thick film printing method, but of course, the film may be formed by the sputtering method or the like and the pattern may be formed by the photolithography method.

Next, the first wiring layer 12 is formed (FIG. 12).
(B)). As the method for forming the wiring layer, the same forming method as the method for forming the electrode in the vicinity of the electron-emitting portion can be applied. It can be reduced, which is advantageous. Therefore, it is advantageous to use the thick film printing method. Of course, thin film wiring can be applied, but it takes a long time to increase the film thickness.

Next, the first wiring layer 12 which is a feature of the present invention
A complementary insulating layer 14 for separating the second wiring layer 13 and the second wiring layer 13 in a direction parallel to the substrate surface is formed (FIG. 12).
(C)). As a forming method, the same forming method as the forming method of the electron emitting portion vicinity electrode can be applied, but the thick film printing method is preferable in order to maximize the effects of the present invention. By providing this insulating layer 14, the interlayer insulating layer 15 and the second
Even if the wiring layer 13 is slightly misaligned, contact between the second wiring layer 13 and the device electrodes 10 and 11 and between the second wiring layer 13 and the first wiring layer 12 is prevented.

Conventionally, the device electrode 10 and the second wiring layer 13 were electrically connected through a contact hole or opening provided in the interlayer insulating layer, but the interlayer insulating layer was formed by a thick film printing method. However, there is a problem in that the contact hole or the opening is easily crushed due to the declining insulation pace, and it is difficult to obtain a sufficient contact. However, by providing the complementary insulating layer 14 for separating the first wiring layer 12 and the second wiring layer 13 which are the features of the present invention in the direction parallel to the substrate surface, The degree of freedom in the shape of the interlayer insulating layer 15 for making contact with the device electrode 10 can be increased. For example, the contact between the second wiring layer 13 and the element electrode 10 can be ensured by forming the inter-layer insulating layer 15 so as not to exist above the element electrode 10 as shown in FIG. In addition, due to the presence of the complementary insulating layer 14 for separating the first wiring layer and the second wiring layer in the direction parallel to the substrate surface, which is a feature of the present invention, the short circuit in the Y direction of the device is prevented. Can be prevented.

Next, the first wiring layer 12 and the second wiring layer 1
An interlayer insulating layer 15 is formed to separate 3 in the direction perpendicular to the substrate surface (FIG. 12D). In FIG. 2, as an example, the interlayer insulating layer 15 is formed after forming the complementary insulating layer 14 for separating the first wiring layer and the second wiring layer in the direction parallel to the substrate surface. Of course, the complementary insulating layer 14 for separating the first wiring layer and the second wiring layer in the direction parallel to the substrate surface may be formed after forming the insulating layer 15 first. As a forming method, the same forming method as that for the first wiring layer can be applied.

Next, the second wiring layer 13 is formed on the interlayer insulating layer 15 (FIG. 12E). The second wiring layer is connected to the device electrode 10 at the notched discontinuous portion on the device electrode 10 of the interlayer insulating layer 15. As a forming method, the same forming method as that for the first wiring layer can be applied.

Finally, the electron emission portion forming thin film 16 is formed to complete the element (one element) for the electron emitting element (FIG. 12 (f)). As the film forming method and the electron emitting portion (surface conduction electron-emitting device) forming method, a conventional method can be applied as it is (described later).

Although one element has been described in the present description,
By forming a plurality of these at the same time, the structure of the electron source substrate having a simple matrix structure is completed.

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

The features of the structure and manufacturing method of the surface conduction electron-emitting device according to the present invention are as follows. (1) The thin film for forming an electron emission portion before energization treatment called forming is a thin film made of fine particles formed by dispersing a fine particle dispersion, or a thin film made of fine particles formed by heating and burning an organic metal or the like. , Basically composed of fine particles. (2) The thin film including the electron emitting portion after energization processing called forming is basically composed of fine particles together with the electron emitting portion and the thin film including the electron emitting portion.

5 (a) and 5 (b) are a plan view and a sectional view, respectively, showing the construction of a basic surface conduction electron-emitting device according to the present invention. The basic structure of the device according to the present invention will be described with reference to FIG. 5. In the electron source substrate and the image forming apparatus of the present invention, as will be described later, a large number of the surface conduction electron-emitting devices are formed on the same substrate. It is formed together with the wiring electrode.

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

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

As a material for the device electrodes 5 and 6 which face each other, a general conductor is used, for example, Ni, Cr, Au, M.
In, a printed conductor composed of a metal or an alloy of o, W, Pt, Ti, Al, Cu, Pd or the like, a metal or a metal oxide of Pd, Ag, Au, RuO ₂ , Pd-Ag or the like, and glass or the like, In ₂ Examples include transparent conductors such as O ₃ —SnO ₂ and semiconductor materials such as polysilicon. Element electrode spacing L1
Is a few angstroms to several hundreds of micrometers, and is a photolithography technology that is the basis of the manufacturing method of the device electrodes, that is, the performance of the exposure machine and the etching method, the voltage applied between the device electrodes and the electric field strength capable of emitting electrons. Etc., but is preferably several micrometers to several tens of micrometers. Element electrode length W1,
The film thickness d of the device electrodes 5 and 6 is appropriately designed from the viewpoints of the resistance value of the electrodes, the connection with X and Y wirings described later, the placement of a large number of arranged electron sources, and the like. , Several micrometers to several hundreds of micrometers, and the film thickness d of the device electrodes 5, 6 is several hundreds of angstroms to several thousand angstroms.

A thin film 4 including an electron emitting portion formed between the device electrodes 5 and 6 facing each other and on the device electrodes 5 and 6.
Includes the electron emitting portion 3, but is not limited to the case shown in FIG. 5B and may not be formed on the device electrodes 5 and 6. In other words, it may not be installed on the insulating substrate 1 on the electron emission portion forming thin film 2 and the opposing device electrodes 5 and 6 which will be described later. That is, not only in the case shown in FIG. 5B, but also in the case where the device electrodes 5 and 6 are laminated in this order on the insulating substrate 1. In addition, the entire space between the opposing device electrodes 5 and 6 may function as an electron emitting portion depending on the manufacturing method. The film thickness of the thin film 4 including the electron emitting portion is several thousand angstroms rather than several angstroms. This film thickness is the device electrode 5,6
Step coverage, electron emission part 3 and device electrode 5,
The resistance value between 6 and the particle size of the conductive fine particles of the electron emission portion 3,
It is appropriately set according to the energization processing conditions and the like described later. The resistance value shows a sheet resistance value of 10 ³ to 10 ⁷ ohm / □. Pd, Pt, Ru, Ag, Au, T will be given as specific examples of the material forming the thin film 4 including the electron emitting portion.
i, In, Cu, Cr, Fe, Zn, Sn, Ta, W,
Metals such as Pb, PdO, SnO ₂ , In ₂ O ₃ , Pb
O, Sb ₂ O _{3 and} other oxides, HfB ₂ , ZrB ₂ , La
Borides such as B ₆ , CeB ₆ , YB ₄ and GdB ₄ , Ti
Examples thereof include carbides such as C, ZrC, HfC, TaC, SiC and WC, nitrides such as TiN, ZrN and HfN, semiconductors such as Si and Ge, and carbon.

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 a state where the fine particles are individually dispersed and arranged but also in a state where the fine particles are adjacent to each other or overlap each other (islands). The particle size of the fine particles is several angstroms to several thousand angstroms, preferably 10 angstroms to 200 angstroms.

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. In addition, the cracks may contain conductive fine particles having a particle diameter of several angstroms to several hundred angstroms. 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 contain carbon and 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.
Shown in Reference numeral 2 is a thin film for forming an electron emitting portion, and examples thereof include a fine particle film.

Hereinafter, the manufacturing method will be described step by step with reference to FIGS. (1) After the insulating substrate 1 is thoroughly washed with a detergent, pure water and an organic solvent, a device electrode material is deposited by a vacuum deposition method, a sputtering method or the like, and then a device electrode is formed on the surface of the insulating substrate 1 by a photolithography technique. 5 and 6 are formed (Fig. 6)
(A)). (2) The organic metal thin film is formed by applying the organic metal solution on the insulating substrate on which the element electrodes 5 and 6 are formed between the element electrodes 5 and 6 provided on the insulating substrate 1 and leaving it to stand. Form. The organic metal solution means Pd, Ru,
Ag, Au, Ti, In, Cu, Cr, Fe, Zn, S
It is a solution of an organic compound containing a metal such as n, Ta, W, or Pb as a main element. After that, the organometallic thin film is heat-fired and patterned by lift-off, etching, etc.
The thin film 2 for forming the electron emitting portion is formed (FIG. 6B).

Although the organic metal coating method has been described here, the present invention is not limited to this, and a vacuum vapor deposition method, a sputtering method, a chemical vapor deposition method, a dispersion coating method, a depping method, a spinner method or the like can be used. It may be formed. (3) Subsequently, an energization process called forming is performed. In the energization forming, energization is performed by applying a voltage between the device electrodes 5 and 6 by a power source (not shown), and the thin film 2 for forming the electron-emitting portion is locally destroyed, deformed or altered to form a portion having a changed structure. It is what makes me.
The part where the structure is locally changed is called an electron emitting part 3 (FIG. 6C). As described above, the electron emitting portion 3
Applicants have observed that is composed of conductive fine particles.

Next, FIG. 7 shows an example of the voltage waveform of the forming process.

A pulse waveform is particularly preferable as the voltage waveform, and a voltage pulse having a constant pulse peak value is continuously applied (FIG. 7A) and a voltage pulse is applied while increasing the pulse peak value ( 7 (b)). First,
A case where the pulse peak value is a constant voltage (FIG. 7A) will be described.

In FIG. 7A, T1 and T2 are the pulse width and pulse interval of the voltage waveform. T1 is 1 microsecond to 10 milliseconds, T2 is 10 microseconds to 100 milliseconds, and the peak value of the triangular wave is set. The (peak voltage during energization forming) is appropriately selected according to the form of the surface conduction electron-emitting device, and is applied for several seconds to several tens of minutes under an appropriate vacuum atmosphere, for example, in a vacuum atmosphere of about 10 ⁻⁵ torr. 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. The peak value, pulse width, pulse interval, etc. are not limited to the above values,
It is possible to select a desired value such that the electron emitting portion is well formed.

T1 and T2 in FIG. 7B are shown in FIG.
As in (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 this case, in the energization forming process, the device current is measured during the pulse interval T2 while applying a voltage that does not locally destroy or deform the electron emission portion forming thin film 2, for example, a voltage of about 0.1V. The resistance value is obtained, and the energization forming is terminated when the resistance value is, for example, 1 M ohm 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, a vacuum degree of about 10 ⁻⁴ to 10 ⁻⁵ torr,
Similar to energization forming, it is a process of repeatedly applying a voltage pulse with a constant pulse peak value.Carbon or a carbon compound derived from an organic substance existing in a vacuum is deposited on a thin film for forming an electron emission portion, and the device current This is a process of remarkably changing If and emission current Ie. The activation process ends while the device current If and the emission current Ie are being measured, for example, when the emission current Ie is saturated. Further, it is preferable that the applied voltage pulse is an operation drive voltage.

The carbon or carbon compound is graphite (both single and polycrystalline) or amorphous carbon (a mixture of amorphous carbon and polycrystalline graphite), and its film thickness is It is preferably 500 angstroms or less, more preferably 300 angstroms or less.

It is preferable that the electron-emitting device thus produced is driven and operated in an atmosphere having a vacuum degree higher than the vacuum degree in the forming step and the activation step. In addition, it is desirable to operate and drive after heating at 80 ° C. to 150 ° C. in an atmosphere of higher vacuum degree. The degree of vacuum higher than the degree of vacuum formed by the forming step or activation is, for example, a degree of vacuum of about 10 ⁻⁶ or more, more preferably an ultra-high vacuum system, in which carbon or a carbon compound is newly added to the electron-emitting portion. The degree of vacuum is such that it is hardly deposited on the forming thin film. By doing so, the device current If and the emission current Ie can be stabilized.

Next, the basic characteristics of the electron-emitting device according to the present invention produced by the above device structure and manufacturing method will be described with reference to FIGS. 8 and 9.

FIG. 8 is a schematic block diagram of a measurement / evaluation apparatus for measuring the electron emission characteristics of the element having the structure shown in FIG. In FIG. 8, 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 source 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 an 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 3 of the device, 93 is a high-voltage power supply for applying a voltage to the anode electrode 94, and 92 is emission emitted from the electron emission portion 3 of the device An ammeter for measuring the current Ie. To measure the device current If and the emission current Ie of the electron-emitting device, a power source 91 and an ammeter 90 are connected to the device electrodes 5 and 6, and a power source 9 is provided above the electron-emitting device.
An anode electrode 94 that connects 3 and the ammeter 92 is arranged. Further, the 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 device can be measured and evaluated under a desired vacuum. The voltage of the anode electrode can be measured in the range of 1 to 10 kV, and the distance H between the anode electrode and the electron-emitting device can be measured in the range of 3 to 8 mm.

FIG. 9 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. 9 is shown in arbitrary units, and the emission current Ie is approximately 10 times the device current If.
It is about 1/00. As is clear from FIG. 9, this electron-emitting device has three characteristics with respect to the emission current Ie.

First, when an element voltage higher than a certain voltage (called a threshold voltage, Vth in FIG. 9) is applied to this element, the emission current Ie rapidly increases. On the other hand, below 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. In addition, FIG. 9 shows an example of the characteristic (M1) in which the element current If monotonously increases with respect to the element voltage Vf. However, in addition to this, the element current If has a negative voltage control type with respect to the element voltage Vf. It may also exhibit resistance (VCNR) characteristics. Also in this case, the electron-emitting device has the above-mentioned three characteristics. The surface conduction electron-emitting device in which the conductive fine particles are dispersed in advance can be configured by partially modifying the basic manufacturing method of the basic device configuration of the present invention.

Next, the electron source substrate 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 in parallel on the substrate. The arrangement method of the surface conduction electron-emitting devices includes a ladder-type arrangement (hereinafter referred to as a ladder-type arrangement electron source substrate) in which the surface conduction electron-emitting devices are arranged in parallel and both ends of each element are connected by wiring. A simple matrix arrangement (hereinafter referred to as a matrix-type arrangement electron source substrate) in which an X-direction wiring and a Y-direction wiring are connected to a pair of device electrodes of a surface conduction electron-emitting device can be mentioned. An image forming apparatus having a ladder-type arranged electron source substrate requires a control electrode (grid electrode) which is an electrode for controlling the flight of electrons from the electron-emitting device.

The configuration 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, 1
14 is a surface conduction electron-emitting device, and 115 is a wire connection.
In the figure, the insulating substrate 111 is the above-mentioned glass or the like, and the size and the thickness of the insulating substrate 111 depend on the number of surface-conduction type electron-emitting devices and the design shape of each device, and when the electron source is used. When configuring a part of the container, it is appropriately set depending on the conditions for maintaining the container in vacuum.

The m X-direction wirings 112 are Dx1 and Dx.
2, ..., Dxm, a desired patterned conductive metal or the like on the insulating substrate 111, and a material such that a substantially uniform voltage is supplied to a large number of surface conduction elements. , Film thickness, wiring width, etc. are set. The Y-direction wiring 113 is composed of n wirings Dy1, Dy2, ..., Dyn. Like the X-direction wiring 112, the Y-direction wiring 113 is composed of a desired patterned conductive metal or the like, and has a large number of surface conduction electrons. The material, film thickness, wiring width, etc. are set so that a substantially uniform voltage is supplied to the emitting element. An interlayer insulating layer (not shown) is provided between the m number of X-direction wirings 112 and the n number of Y-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 SiO ₂ or the like, and is formed in a desired shape on the entire surface or a part of the insulating substrate 111 on which the X-direction wiring 112 is formed. In particular, the X-direction wiring 112 and the Y-direction wiring 113 are formed. The film thickness, material, and manufacturing method are appropriately set so as to withstand the potential difference at the intersection. The X-direction wiring 112 and the Y-direction wiring 113 are drawn out as external terminals. Although an example has been described in which the n Y-direction wirings 113 are provided on the m X-direction wirings 112 via the interlayer insulating layer, the m Y-direction wirings 113 are provided on the n Y-direction wirings 113. The wiring 112 may be provided via an interlayer insulating layer.

Further, similarly to the above, each of the opposing device electrodes (not shown) of the surface conduction electron-emitting device 114 has m X-direction wirings 112 of Dx1, Dx2, ... Dxm, Dy1, Dy2, ... Dyn n Ys
It is electrically connected to the direction wiring 113 by a connection 115.

Note that m X-direction wirings 112 and n Y-direction wirings are provided.
Even if some or all of the constituent elements of the directional wiring 113, the connection 115, and the conductive metal of the device electrode are the same,
In addition, they may be different from each other, Ni, Cr, Au, M
a metal or alloy such as o, W, Pt, Ti, Al, Cu, Pd, or a metal such as Pd, Ag, Au, RuO ₂ , Pd-Ag, or a printed conductor composed of metal oxide and glass, It is appropriately selected from a transparent conductor such as In ₂ O ₃ —SnO ₂ and a semiconductor material such as polysilicon. The surface conduction electron-emitting device may be formed on either the insulating substrate 111 or an interlayer insulating layer (not shown).

The X-direction wiring 112 is electrically connected to a scanning signal applying means (not shown) for applying a scanning signal for arbitrarily scanning the row of the surface conduction electron-emitting devices 114 arranged in the X direction. It is connected. On the other hand, Y-direction wiring 1
13 is a surface conduction electron-emitting device 1 arranged in the Y direction.
It is electrically connected to a modulation signal generating means (not shown) for applying a modulation signal for arbitrarily modulating each of the 14 columns.

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. With the above configuration, individual elements can be selected and driven independently using only simple matrix wiring.

Next, an image forming apparatus using the electron source having the simple matrix arrangement created as described above will be described with reference to FIGS. 2 is a basic configuration diagram of the image forming apparatus, and FIG. 3 is a pattern of a fluorescent film which is used in the image forming apparatus and which constitutes a pixel.

In FIG. 2, 31 is an electron source substrate on which an electron-emitting device is formed as described above, 34 is an electron-emitting device, and 35 and 36 are connected to a pair of device electrodes of a surface conduction electron-emitting device. X-direction wiring and Y-direction wiring. 32 is a rear plate to which the electron source substrate 31 is fixed, 4
Reference numeral 0 is a face plate on which the fluorescent film 38 on the inner surface of the glass substrate 37 and the metal back 39 are formed, 33 is a supporting frame, and frit glass or the like is applied to the rear plate 32, the supporting frame 33 and the face plate 40, and the atmosphere The envelope 41 is configured by sealing by firing in air or nitrogen at 400 to 500 ° C. for 10 minutes or more.

The envelope 41 is composed of the face plate 40, the support frame 33, and the rear plate 32 as described above, but since the rear plate 32 is provided mainly for the purpose of reinforcing the strength of the electron source substrate 31, the electron source When the substrate 31 itself has a 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, the electronic substrate 31, and the outside. The envelope 41 may be configured. Furthermore, the face plate 4
It is also possible to form the envelope 41 having sufficient strength against atmospheric pressure by installing an atmospheric pressure resistant support member called a spacer between the rear plate 32 and the rear plate 32.

In FIG. 2, 38 is a fluorescent film. Fluorescent film 38
In the case of monochrome, is composed of only phosphor. In the case of the color fluorescent film 38, as shown in FIG.
3 and a black member 42 called a black stripe or a black matrix that fills the gap. 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 of the black stripe is not limited to the commonly used material containing graphite as a main component, but is not limited to this as long as the material transmits and reflects little light.

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

Further, a metal back 39 is usually provided on the inner surface side 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 that goes toward the inner surface side of the light emission of the phosphor 43 to the face plate 40 side, the electron beam acceleration voltage Is to act as an electrode for applying a voltage, and to protect the phosphor 43 from damage due to collision of negative ions generated in the envelope. The metal back 39 can be formed by forming the fluorescent film 38, smoothing the inner surface of the fluorescent film 38 (usually called filming), and then depositing Al by a vacuum deposition method or the like. The face plate 40 may be provided with a transparent electrode (not shown) on the outer surface side of the fluorescent film 38 in order to further enhance the conductivity of the fluorescent film 38.

When performing the above-mentioned sealing, in the case of color, it is necessary to make sufficient alignment because the phosphors of the respective colors and the electron-emitting devices must correspond to each other.

The envelope 41 is connected to an exhaust pipe (not shown) through the exhaust pipe 10.
Vacuum is set to about ^-7 torr and sealing is performed. Further, a getter process may be performed to maintain the degree of vacuum after the envelope 41 is sealed. This is a method of heating a 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 sealing the envelope 41. Then, it is a process of forming a vapor deposition film. The getter usually has Ba as a main component,
The vacuum of 1 × 10 ^{−5 to} 1 × 10 ⁻⁷ torr is maintained by the adsorption action of the deposited film. The steps after the forming of the surface conduction electron-emitting device are appropriately set.

In the image forming apparatus of the present invention completed as described above, each electron-emitting device has a terminal Dx outside the container.
1 to Dxm and Dy1 to Dyn are applied to cause electrons to be emitted, 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 and exciting and emitting light.

The structure described above is a schematic structure necessary for producing a suitable image forming apparatus used for image display and the like. For example, the detailed parts such as the material of each member are limited to the above contents. Instead, it is appropriately selected to suit the application of the image forming apparatus.

[0076]

Next, embodiments of the present invention will be described.

Example 1 In this example, an electron source substrate having the structure shown in FIG. 1 was prepared, and an image forming apparatus was prepared by using the substrate.

The first embodiment will be described with reference to FIG. FIG. 12 is a process diagram illustrating the creation process.

First, the device electrodes 10 and 11 are formed on a washed substrate (here, a soda lime glass substrate is used). In this example, the thick film printing method was used as the film forming method. The thick film paste material used here is
In the MOD paste, the metal component is Au. The printing method was a screen printing method. 20 after printing at 110 ℃
After drying for a minute, the main calcination was performed. Firing temperature is 580
At ° C, the peak retention time is about 8 minutes. The film thickness after printing and firing was 0.3 μm.

At the same time, a lead electrode (not shown) for connection with an external drive circuit is formed at the same time. This shortens the process by one process.

Next, the first wiring layer 12 is formed. In this example, the thick film screen printing method was used. As the paste material, Noritake NP-4028A was used.

Next, the first wiring layer 12 and the second wiring layer 1
A complementary insulating layer 14 for separating 3 in the direction parallel to the substrate surface was formed using a thick film screen printing method.
The complementary insulating layer 14 covers one end side of the device electrodes 10 and 11, and further covers the first wiring layer 12 in a crossing manner. The paste is a mixture of PbO as a main component and a glass binder, the firing temperature is 580 ° C., and the peak holding time is 8 minutes.

Next, an interlayer insulating layer 15 for separating the first wiring layer and the second wiring layer in the direction perpendicular to the substrate surface was formed by using the thick film screen printing method. The insulating layer 15 is formed between the device electrodes 10 and a part of the insulating layer 15 is provided between the device electrodes 1.
It was on the 0 side. The paste is a mixture of PbO and a glass binder, and the firing temperature is 5
The temperature was 80 ° C. and the peak retention time was 8 minutes. Printing and firing were repeated twice to ensure sufficient insulation.

Finally, the second wiring layer 13 was formed in the same manner as the first wiring layer. The second wiring layer is the insulating layer 15
The element electrode 10 is connected through the discontinuous portion formed in the. A thick film screen printing method was used as a forming method, and the film was formed in the same manner as described above.

Thus, the matrix wiring portion is completed. Of course, the paste material, printing method, etc. are not limited to those described here.

After the wiring was completed, a thin film 16 for forming an electron emitting portion was formed. First, organopalladium (C) is formed on the device electrodes 10 and 11 to the electron emission portion formed by the above-described printing method.
CP4230 and Okuno Seiyaku Co., Ltd. were spin-coated by a spinner, and then heat-treated at 300 ° C. for 10 minutes to form a thin film 16 for forming an electron-emitting portion made of Pd. The electron emission forming thin film 16 thus formed is composed of fine particles containing Pd as a main element and has a film thickness of 10 nm.
The sheet resistance value was 5 × 10E4 Ω / □. 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 a state in which fine particles are individually dispersed and arranged but also in a state in which fine particles are adjacent to each other or overlap each other (also in an island shape. (Including), and the particle size thereof means the size of fine particles whose particle shape can be recognized in the above state.

By patterning this palladium film using the photolithography method, the manufacturing process of the element before forming is completed.

Next, an example in which an image forming apparatus is configured by using the electron source substrate created as described above will be described with reference to FIGS. 2 and 3.

After fixing the electron source substrate 31 on which a large number of surface conduction electron-emitting devices are formed on the rear plate 32, the face plate 40 (the fluorescent film 38 and the metal on the inner surface of the glass substrate 37 is placed 5 mm above the substrate 31. (Where the back 39 is formed) is disposed via the support frame 33, frit glass is applied to the joint portion of the face plate 40, the support frame 33, and the rear plate 32, and the temperature is 400 ° C. or more in the atmosphere or the nitrogen atmosphere. It was sealed by baking at 500 ° C. for 10 minutes (see FIG. 2). The substrate 31 was also fixed to the rear plate 32 with frit glass.

In FIG. 2, 34 is an electron-emitting device and 3
Reference numerals 5 and 36 denote wirings in the X direction and the Y direction, respectively.

In the case of monochrome, the fluorescent film 38 is made of only a fluorescent material. In this embodiment, the fluorescent material has a stripe shape (see FIG. 3), and the black stripe 42 is first formed.
Was formed, and each of the phosphors 43 was applied to the gap portion to form the phosphor film 38. As the material of 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 the slurry method.

A metal back 39 is usually provided on the inner surface side of the fluorescent film 38. The metal back was produced by performing a smoothing treatment (usually called filming) on the inner surface of the fluorescent film after producing the fluorescent film, and then vacuum-depositing Al.

The face plate 40 may be provided with a transparent electrode (not shown) on the outer surface side of the fluorescent film 38 in order to further enhance the conductivity of the fluorescent film 38, but in this embodiment, only a metal back is used. It was omitted because sufficient conductivity was obtained.

At the time of performing the above-mentioned sealing, in the case of color, the phosphors of the respective colors must correspond to the electron-emitting devices, so that sufficient alignment was 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, electrons are transferred through the external terminals Dx1 to Dxm and Dy1 to Dyn. A voltage was applied between the device electrodes of the emitting device 34, and the electron emitting unit forming thin film 2 was energized (forming process) to form the electron emitting unit 3. FIG. 7 shows the voltage waveform of the forming process.

In FIG. 7, 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 performed for 60 seconds in a vacuum atmosphere of about 1 × 10 ⁻⁶ torr.

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

Next, at a vacuum degree of about 10 ^-6 torr, an unillustrated exhaust pipe was heated by a gas burner to weld and seal the envelope.

Finally, in order to maintain the degree of vacuum after sealing,
Getter processing was performed. This is a process for forming a vapor deposition film by heating a getter arranged at a predetermined position (not shown) in the image forming apparatus by resistance heating after sealing. The getter was mainly composed of Ba. The vacuum function of, for example, 1 × 10 ⁻⁵ to 1 × 10 ⁻⁷ torr is maintained by the adsorption action of the vapor deposition film.

In the image forming apparatus of the present invention completed as described above, a scanning signal and a modulation signal (not shown) are generated in each surface conduction electron-emitting device through the terminals Dx1 to Dxm and Dy1 to Dyn outside the container. By applying each by means to emit electrons, a high voltage of several kV or more is applied to the metal back 39 through the high voltage terminal Hv, the electron beam is accelerated, collides with the fluorescent film 38, excited, and emits an image. Was displayed.

Further, according to the structure of this embodiment, a large number of surface conduction electron-emitting devices can be easily arranged in an X, Y matrix, which is suitable for the production of a large-screen image forming apparatus.

[0102]

As a result of the realization of the structure and manufacturing method of the present invention, The insulation between the scanning side wiring and the signal side wiring and the reliability of the device electrodes and contacts are improved.

2. The tolerance for misalignment of the upper wiring (scanning side or signal side) with respect to the interlayer insulating layer is expanded.

3. Since the short circuit between the device electrodes due to the upper wiring (scanning side or signal side) can be reduced, it is possible to arrange the electron-emitting devices with high density.

With the above effects, it is possible to reduce the manufacturing cost by improving the reliability and the yield, and it is possible to display a high-definition image when applied to an image forming apparatus.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an electron source substrate formed by X, Y matrix wiring in a first embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view showing a configuration example of an image forming apparatus of the present invention.

3A and 3B are diagrams showing a configuration example of a fluorescent film in the image forming apparatus of the present invention.

FIG. 4 is a configuration diagram showing an example of a surface conduction electron-emitting device.

5A and 5B are schematic configuration diagrams showing an embodiment of a surface conduction electron-emitting device according to the present invention, FIG. 5A being a plan view and FIG. 5B being a side view.

6A, 6B, and 6C are schematic cross-sectional views showing an example of a manufacturing process of the surface conduction electron-emitting device according to the present invention.

7A and 7B are waveform charts each showing an example of a voltage waveform of energization forming of the surface conduction electron-emitting device.

FIG. 8 is a schematic configuration diagram showing a circuit for measuring and evaluating electron emission characteristics of a surface conduction electron-emitting device.

FIG. 9 is a graph showing current-voltage characteristics of the surface conduction electron-emitting device.

FIG. 10 is a schematic explanatory diagram of an electron source substrate configured by simple matrix wiring of a large number of surface conduction electron-emitting devices.

FIG. 11 is a partially cutaway perspective view showing another configuration example of the image forming apparatus of the present invention.

FIG. 12 is a process chart showing an example of a method for manufacturing an electron source substrate of the present invention.

[Explanation on the sign]

DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Thin film for forming an electron emitting portion 3 Electron emitting portion 4 Thin film including an electron emitting portion 5 Element electrode 6 Element electrode 10 Element electrode 11 Element electrode 12 First wiring layer 13 Second wiring layer 14 Complementary insulating layer 15 Interlayer Insulation Layer 16 Electron Emission Portion Forming Thin Film 31 Electron Source Substrate 32 Rear Plate 33 Support Frame 34 Electron Emitting Element 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 device 115 Connection 120 Electron source substrate 121 Surface conduction electron emission Element 130 Grid electrode 131 Holes through which electrons pass 132 ox, Dox2, G1 is connected to the vessel terminals 133 grid electrodes 130 made of · · · Doxm, G
2, ... Gn external terminal made of container 134 Electron source substrate

Claims (7)

[Claims] 1. An electron-emitting device having device electrodes facing each other is arranged at a position orthogonal to a scanning-side wiring and a signal-side wiring, and the electron emission is performed by sequentially selecting one set or a plurality of sets of the wiring. In an electron source substrate of a simple matrix type configured by disposing a plurality of electron-emitting devices that are energized on the substrate, a supplement for preventing electrical contact between the device electrodes and one of the wirings facing each other An electron source substrate comprising an insulating layer. 2. The electron source substrate according to claim 1, wherein the complementary insulating layer is formed so as to cover at least one end side of both device electrodes facing each other and one of the wirings. 3. The electron source substrate according to claim 1, wherein the electron-emitting device is a surface conduction electron-emitting device in which an electron-emitting portion is formed by subjecting a thin film for forming an electron-emitting portion to an energization process. . 4. The method of manufacturing an electron source substrate according to claim 1, wherein either one of an interlayer insulating layer for separating a scanning side wiring and a signal side wiring and the complementary insulating layer is insulated. A method for manufacturing an electron source substrate, wherein the layer is formed after the other insulating layer is formed. 5. The method of manufacturing an electron source substrate according to claim 1, wherein a thick film printing method is used to form wirings, insulating layers, or electrodes. Method. 6. An electron source substrate according to claim 1, and a phosphor that emits visible light upon irradiation with an electron beam that is arranged so as to face each electron-emitting device of the electron source substrate. Image forming apparatus including at least pixels. 7. An image forming apparatus comprising the electron source substrate according to claim 1 incorporated therein.