JP2002313221A - Manufacturing method of electron emitting element, electron source, display element, imaging device, and etchant for platinum material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten and stabilize the time for etching a platinum material, when manufacturing an electron emitting element, and to stabilize the quality of the electron emitting element. SOLUTION: For the manufacturing method of the electron emitting element composed of a process of partially applying liquid drop of a metal compound solution containing electron emitting material between electrodes facing each other, a process of burning, a process of etching, and a process of forming an electron-emitting part after going through a process of electricity conduction treatment, aqua regia in which, at least one kind of metal ion chosen from sodium, potassium, lithium, cesium, or rubidium is dissolved, is used as an etchant in the etching process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an electron-emitting device used as an electron source in an electron beam generator, an image forming apparatus, and the like, and an electron source, a display device, and a method of manufacturing an image forming apparatus using the same. Things. More specifically, the present invention relates to a method for manufacturing an electron-emitting device manufactured by using an inkjet method, and a method for manufacturing an electron source, a display device, and an image forming apparatus using the same. Further, the present invention relates to an etching solution for a platinum material such as a platinum electron-emitting film and a platinum electrode used in the manufacturing process of the electron-emitting device, the electron source, the display device, and the image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, two types of electron-emitting devices using a thermionic electron source and a cold cathode electron source have been known. Examples of the cold cathode electron source include a surface conduction electron-emitting device (hereinafter abbreviated as SCE).

[0003] The SCE type utilizes a phenomenon in which an electron is emitted when a current flows through a small-area thin film formed on a substrate in parallel with the film surface. This surface conduction electron-emitting device is a device using an In ₂ O ₃ / SnO ₂ thin film [M. Hartwellland C.I. G. FIG. Fonst
ad: "IEEE Trans. ED Conf."
519 (1975)]. As a typical example of these surface conduction electron-emitting devices, the aforementioned M.I. FIG. 14 schematically shows an element configuration of the Hartwell. In the figure, reference numeral 5 denotes an insulating substrate. Reference numeral 6 denotes a thin film for forming an electron emitting portion, which is formed of a metal oxide thin film or the like formed by sputtering in an H-shaped pattern, and the electron emitting portion 7 is formed by an energization process called energization forming described later. Reference numeral 8 denotes a thin film including an electron-emitting portion. In the drawing, the element electrode interval L1 is 0.5 mm to 1 mm, and the electrode width W is
It is set at 0.1 mm.

Conventionally, in these surface conduction electron-emitting devices, the electron-emitting portion 7 is generally formed by subjecting the thin film 6 for forming an electron-emitting portion to an energization process called forming before performing electron emission. It was a target. That is, forming refers to an electron emission in which a voltage is applied to both ends of the thin film 6 for forming an electron emission portion, the thin film for forming an electron emission portion is locally broken, deformed or deteriorated, and a high resistance state is obtained. That is, the part 7 is formed. In the electron emitting portion 7, a crack is generated in a part of the thin film 6 for forming the electron emitting portion, and the electron is emitted from the vicinity of the crack. Hereinafter, the thin film 6 for forming an electron emitting portion including an electron emitting portion formed by forming is referred to as a thin film 8 including an electron emitting portion. The surface-conduction electron-emitting device that has been subjected to the forming process is configured to apply a voltage to the thin film 8 including the above-described electron-emitting portion and to cause a current to flow through the device, thereby causing the electron-emitting portion 7 to emit electrons. .

[0005] However, these conventional surface conduction electron-emitting devices have various problems in practical use, but the present inventors have intensively studied various improvements as described later, and have found various problems in practical use. Has been solved. Of these conventional techniques, a method often employed is, for example, as disclosed in Japanese Patent Application Laid-Open No. 1-200532, in a method of manufacturing an electron-emitting device, for forming a metal or metal oxide for forming treatment. It is known that a thin film of an organometallic compound is formed between element electrodes and subjected to a heat treatment called baking in order to obtain a thin film for forming an electron emission portion of fine particles of a substance.

In this heat treatment, a thin film of fine particles of a metal or a metal oxide is generated by thermally decomposing an organometallic compound in the air.

In the case where the electron emission film and the metal electrodes on both sides of the electron emission portion are made of platinum, aqua regia has been conventionally used as an etching solution in photolithography.

[0008]

However, the conventional methods for manufacturing the above-described thin film for forming an electron-emitting portion and the surface-conduction type electron-emitting device have the following problems.

In the method of manufacturing this thin film by the bubble jet method, the pressure of the manufacturing atmosphere is normal pressure and the temperature is normal temperature. When using the bubble jet method as the inkjet method, the heater temperature may be instantaneous,
It can be hundreds of degrees. For this reason, depending on the type of the material for forming the electron emission film, the material is thermally decomposed on the heater, and there are inherent problems such as deterioration in ejection, an increase in thickness variation, and an increase in electron emission amount.

In the case where the electron-emitting film and the metal electrodes on both sides of the electron-emitting portion are made of platinum, aqua regia, which has been conventionally used for etching in photolithography, takes a long time to etch, There is a problem in the manufacturing process that is unstable.

An object of the present invention is to improve such disadvantages of the prior art, and in particular, to improve aqua regia used as an etching solution for a platinum electrode for an electron-emitting device,
An object of the present invention is to provide a method of manufacturing a highly reliable electron-emitting device by improving an etching process. Another object of the present invention is to provide a method for manufacturing an electron-emitting device for manufacturing an electron-emitting film by a bubble jet method, which solves the above-mentioned problems caused by manufacturing conditions at normal temperature and normal pressure. It is still another object of the present invention to provide a method of manufacturing the electron-emitting device, the electron source, the display device, and the image forming apparatus, which is manufactured using the manufacturing method, with less variation.

[0012]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that platinum used as an element electrode or an electron emitting film of an electron emitting element is added to an aqua regia by adding alkali metal ions. By doing so, the inventors have found that the etching rate can be improved or the concentration of the etching solution can be reduced, and the present invention has been completed.
Further, in the method of manufacturing an electron emission film by a bubble jet method, (1) a condition in which the pressure of the manufacturing atmosphere is lower than normal pressure, or (2) a condition in which the temperature of the manufacturing atmosphere is lower than normal temperature. By using one or both of them, the above-mentioned problems such as the deterioration of the ejection from the nozzle, the variation in the thickness of the formed electron-emitting film, and the variation in the electron emission amount of the electron-emitting device are solved. I found that I can do it.

That is, in the method of manufacturing an electron-emitting device according to the present invention, a step of partially applying a droplet of a metal compound solution containing an electron-emitting material between opposing electrodes;
In a method of manufacturing an electron-emitting device having an etching step and a step of forming an electron-emitting portion through a step of conducting electricity, an etchant used in the etching step is selected from sodium, potassium, lithium, cesium, and rubidium in aqua regia. It is characterized by containing at least one kind of metal ion.

By using a solution containing alkali metal ions in aqua regia as an etching solution for a platinum material such as a platinum electrode or a platinum electron-emitting portion, the required etching time can be reduced, and the required etching time can be stabilized. The quality of the member using the platinum material can be stabilized.

In the present invention, the production atmosphere is preferably under reduced pressure and / or cooling. In an SCE having an electron-emitting portion between opposing electrodes, when a bubble jet method is used as a method for manufacturing an electron-emitting film of the electron-emitting portion, a method for reducing the manufacturing atmosphere or a method for cooling the manufacturing atmosphere includes: By using one or both of them, it is possible to reduce the thermal decomposition of the material for the electron emission film on the heater of the bubble jet and produce a good electron emission film.

The present invention also includes a method for manufacturing an electron source, a display element and an image forming apparatus, and further includes an etching solution for a platinum electrode used in a process for manufacturing an electron-emitting device.

The method for manufacturing an electron source according to the present invention is a method for manufacturing an electron source comprising an electron-emitting device and a means for applying a voltage to the device. It is characterized by being manufactured by a method.

A method for manufacturing a display element according to the present invention is directed to a display comprising an electron emitting element, an electron source having a means for applying a voltage to the element, and a luminous body which emits light by receiving electrons emitted from the element. A method for manufacturing a device, wherein the electron-emitting device is manufactured by the method for manufacturing an electron-emitting device according to the present invention.

According to the method of manufacturing an image forming apparatus of the present invention, there is provided an electron source including an electron-emitting device and a means for applying a voltage to the device, a luminous body that receives light emitted from the device and emits light, And a drive circuit for controlling a voltage applied to the element based on the method. 9. The method according to claim 1, wherein the electron-emitting device is manufactured by the method for manufacturing an electron-emitting device according to the present invention. Is what you do.

Further, in the etching solution for a platinum material of the present invention, the etching solution for dissolving platinum used in the manufacturing process of the electron-emitting device contains sodium, potassium, lithium and aqua regia.
It contains at least one metal ion selected from cesium and rubidium.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing an electron emission film according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view illustrating a method for manufacturing an electron emission film of the present invention. FIG.
1A and 1B are a schematic plan view and a cross-sectional view illustrating a configuration of a surface conduction electron-emitting device to which the present invention can be applied. FIG. 3 is a process chart showing an example of the method for manufacturing an electron-emitting device of the present invention.

The manufacturing method of the present invention will be described below with reference to the drawings. 1) After sufficiently washing the insulating substrate 5 with a detergent, pure water, and an organic solvent, an element electrode material is deposited by a vacuum evaporation method, a sputtering method, or the like, and then, on the surface of the insulating substrate 5 by a photolithography technique. The device electrodes 9 and 10 are formed (see FIG. 3A).

At this time, when platinum is used as an electrode material, an aqua regia added with at least one of sodium, potassium, lithium, cesium, and rubidium ions is used as an etching solution for photolithography. In the case where the electron-emitting portion is made of platinum in the subsequent steps, if there is an etching step, aqua regia containing alkali metal ions is also used. By using this etching solution, the etching rate can be improved, and etching can be performed efficiently with aqua regia that is thinner than in the past.

2) The thin film 6 for forming an electron emitting portion is formed between the device electrode 9 and the device electrode 10 provided on the insulating substrate 5. The formation method uses an organic metal compound or an inorganic metal compound as a raw material, and is manufactured by a bubble jet method. At this time, one or both of a method of reducing the production atmosphere of the bubble jet method and a method of cooling the production atmosphere of the bubble jet method are used. Thus, a thin film is formed, and thereafter, a heat treatment is performed. During the heat treatment, the reduced pressure or the cooled state may be maintained, or one or both of them may be released. By this heat treatment, the thin film is formed into a metal fine particle film or a metal oxide fine particle film, and is patterned by lift-off, etching, or the like.
Is formed (FIG. 3B).

As described above, in the method of manufacturing an electron-emitting device according to the present invention, it is preferable that the droplet applying means is of a bubble jet type. The bubble jet method referred to in the present invention is one type of an ink jet method. There are two types of ink jet systems, one is a bubble jet system and the other is a piezo jet system. The former is a technique in which a heating resistor is heated and foamed to eject a droplet from a nozzle. The latter is a technique in which droplets are ejected by the contraction pressure of a piezo element provided in a nozzle. In the bubble jet method, a liquid such as ink is ejected by using thermal energy, and therefore, there is a heat acting section for applying heat to the liquid. The present invention is mainly effective in the bubble jet method. Preferably, the electron-emitting device is a surface conduction electron-emitting device. Further, it is preferable that the pressure and temperature of the manufacturing atmosphere of the electron-emitting device are lower than normal pressure and / or lower than normal temperature, respectively.

Next, the step of forming the electron-emitting-portion-forming thin film 6 according to the present invention will be described. The metal contained in the organometallic compound or the inorganic metal compound used in the present invention includes Pd, Pt, Ru, Ag, Au, Ti, In,
Cu, Cr, Fe, Zn, Sn, Ta, W, Pb, and the like are used because the electron emission characteristics of the obtained electron emission element are preferable.

As the organometallic compound, an organic acid salt or a cluster thereof, an organic ammine complex, or the like is preferably used from the viewpoint that a good thin film for forming an electron emitting portion can be obtained.

As the inorganic metal compound, halogen compounds of the above metals, nitrates, nitrites, hydrochlorides, amine complexes and the like are preferably used from the viewpoint that a good thin film for forming an electron emitting portion can be obtained.

The organometallic compound or inorganic metal compound selected as described above is dissolved or dispersed in water.

A thin film is formed by applying a droplet of such a raw material solution between the electrodes 9 and 10 by a bubble jet method. In this case, as shown in FIG. The production apparatus 1 is installed in a coolable room 4 provided with a decompression device 2 and a cooling device 3.

For the degree of pressure reduction in the production atmosphere, suitable conditions are selected in consideration of the boiling point of the solvent of the raw material and the thermal decomposition temperature of the raw material. The degree of pressure reduction in the present invention is preferably in the range of less than 1 atmosphere to 0.1 atmosphere.

Similarly, the degree of cooling of the production atmosphere is selected in consideration of the boiling point of the solvent of the raw material, the thermal decomposition temperature of the raw material, the discharge amount of the bubble jet, the discharge interval, and the like. The degree of cooling in the present invention is from 20 ° C. to 1 degree.
C. is preferred.

The principle of lowering the bubble generation temperature by using such a manufacturing apparatus is based on the fact that the boiling point is a function of the atmospheric pressure according to the Clausius-Clapeyron law. However, in the bubble jet method, after being discharged by one bubble, if the temperature drops to a certain extent or more, and the bubble disappears or becomes extremely small, the suction amount of the liquid necessary for the subsequent foaming decreases, The amount of liquid discharged is reduced. In other words, in the present method, the effect is often insufficient only by the reduced pressure, and after the raw material liquid is discharged by one bubble, it is preferable to cool down in order to eliminate the bubble or shrink the bubble very small. Often effective. The principle of this is that, as described above, the volume of the gas and the vapor pressure of the liquid are functions of the temperature, and the lower the temperature, the smaller the volume and the vapor pressure.

The chamber 4 thus decompressed and cooled in this way
Then, after the injection, heat treatment is performed next. Atmospheric conditions during this heat treatment may be either those in which depressurization or cooling is continued, or one or both of them are released.
However, when only cooling is continued, it is better to have a mechanism for removing vaporous pyrolysis products. This exclusion mechanism includes:
There are cooling traps and ventilation mechanisms. In such an atmosphere,
A low-temperature heating (100 ° C. or lower) is performed to form a metal compound thin film. Next, high-temperature heating (150 ° C.) is performed to volatilize and remove moisture. Thereafter, in order to convert the metal compound or metal into an oxide, heat treatment is performed at a higher temperature (300 ° C., 10 minutes or more).

In the case where a material made of platinum is used for the electron-emitting portion and the electrodes, an aqua regia is diluted twice with water, and sodium chloride, potassium chloride, sodium nitrate and potassium nitrate are used as an etching solution for etching the material. And the like, to which 1% by weight to 10% by weight, preferably 2% by weight to 3% by weight of a water-soluble salt of an alkali metal such as an alkali metal is added. It is considered that the principle of this addition effect is that chloroplatinate is more soluble in water than chloroplatinate. When the addition amount is less than 1% by weight, the effect is small, and even if added over 10% by weight, the effect is not further improved. The use of this etchant shortens the required etching time. Also,
Since the life of the solution is prolonged, the difference in the etching time between the new solution and the old solution in mass production is reduced, and the quality of the material is stabilized.

3) Subsequently, an energization process called forming is performed. When power is applied between the device electrodes 9 and 10 using a power supply (not shown), an electron emitting portion 7 having a changed structure is formed at the portion of the thin film 6 for forming an electron emitting portion.
(C)). According to the energization forming, a portion where the structure such as the destruction, deformation or alteration of the thin film 6 for forming the electron emission portion is locally changed is formed. This portion constitutes the electron emission section 7. FIG. 5 shows an example of the voltage waveform of the energization forming.

The voltage waveform is preferably a pulse waveform. FIG.
T1 and T2 in are the pulse width and pulse interval of the voltage waveform. Normally T1 is 1 microsecond to 10 milliseconds, T2
Is set in the range of 10 microseconds to 100 milliseconds. 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. Under such conditions, for example, a voltage is applied for several seconds to several tens minutes. The pulse waveform is not limited to a triangular wave, and a desired waveform such as a rectangular wave can be adopted.

The end of the energization forming process is to locally destroy the thin film 6 for forming an electron emission portion during the pulse interval T2.
By applying a voltage that does not cause deformation, the current can be measured and detected. For example, the element current flowing when a voltage of about 0.1 V is applied is measured, and the resistance value is calculated. When the resistance value indicates 1 M ohm or more, the energization forming is terminated.

4) It is preferable to perform a process called an activation step on the device after the forming. The activation step is a step in which the element current If and the emission current Ie are significantly changed by this step.

The activation step can be performed, for example, by repeatedly applying a pulse in an atmosphere containing an organic substance gas, similarly to the energization forming. This atmosphere can be formed by using an organic gas remaining in the atmosphere when the inside of the vacuum vessel is evacuated using, for example, an oil diffusion pump or a rotary pump, or a vacuum once sufficiently evacuated by an ion pump or the like. It can also be obtained by introducing a gas of an appropriate organic substance therein. The preferable gas pressure of the organic substance at this time varies depending on the above-described application form, the shape of the vacuum vessel, the type of the organic substance, and the like, and is appropriately set according to the case.

Suitable organic substances include organic acids such as aliphatic hydrocarbons of alkane, alkene and alkyne, aromatic hydrocarbons, alcohols, aldehydes, ketones, amines, phenols, carboxylic acids, sulfonic acids and the like. Specific examples thereof include unsaturated hydrocarbons represented by C _n H _{2n + 2} such as methane, ethane and propane, and unsaturated hydrocarbons represented by a composition formula such as C _n H _2n such as ethylene and propylene. Hydrocarbon, benzene, toluene, methanol, ethanol, formaldehyde, acetaldehyde, acetone, methyl ethyl ketone, methylamine, ethylamine, phenol, formic acid, acetic acid, propionic acid and the like can be used. By this treatment, carbon or a carbon compound is deposited on the device from the organic substance existing in the atmosphere, and the device current If and the emission current Ie are significantly changed.

The end of the activation step is determined as appropriate while measuring the device current If and the emission current Ie. The pulse width, pulse interval, pulse crest value, and the like are set as appropriate.

Carbon and carbon compounds include graphite (so-called highly oriented pyrolytic carbon HOPG, pyrolytic carbon P).
G, amorphous carbon GC) and amorphous carbon (refer to amorphous carbon and a mixture of amorphous carbon and the above-mentioned graphite microcrystals), and its film thickness is preferably in the range of 500 ° or less, 300Å
More preferably, it is in the following range. HOPG has almost perfect crystal structure of graphite, and PG has 20 crystal grains.
At about 0 °, the crystal structure is slightly disturbed, and GC indicates that the crystal grains are about 20 °, and the disorder of the crystal structure is further increased.

5) The electron-emitting device obtained through the above steps is preferably subjected to a stabilization step. This step is a step of exhausting the organic substance in the vacuum container. It is preferable to use a vacuum exhaust device that does not use oil so that the oil generated from the device does not affect the characteristics of the element. Specifically, a vacuum exhaust device such as a sorption pump or an ion pump can be used.

In the above-mentioned activation step, oil expansion as an exhaust device is performed.
Using a dispersing pump or a rotary pump
When organic gas derived from oil components is used,
It is necessary to keep the partial pressure as low as possible. Yes inside vacuum container
The partial pressure of the components is almost the same as that of the above carbon and carbon compounds.
1 × 10 with partial pressure that does not accumulate on^-8Torr or less is preferred
And 1 × 10^-TenTorr or less is particularly preferred
No. When evacuating the vacuum vessel further,
The body is heated and adsorbed on the inner wall of the vacuum vessel and the electron-emitting device.
It is preferable to easily exhaust the organic substance molecules. this
The heating condition at this time is preferably 80 to 200 ° C for 5 hours or more.
However, the present invention is not limited to this condition.
Suitable for various conditions such as size, shape, configuration of electron-emitting device, etc.
This is performed under conditions that are appropriately selected. The pressure inside the vacuum vessel is as low as possible
It is necessary to lower, 1-3 × 10 ^-7Torr or less
Preferably, 1 × 10^-8Torr or less is particularly preferred
No.

The atmosphere at the time of driving after performing the stabilization step is preferably the same as the atmosphere at the end of the stabilization treatment, but is not limited to this. If the organic substance is sufficiently removed, Even if the degree of vacuum itself is slightly reduced, sufficiently stable characteristics can be maintained.

By adopting such a vacuum atmosphere, the deposition of new carbon or carbon compound can be suppressed.
As a result, the element current If and the emission current Ie are stabilized.

Hereinafter, a surface conduction electron-emitting device to which the present invention can be applied will be described in detail with reference to the drawings.

The basic structure of a surface conduction electron-emitting device to which the present invention can be applied is roughly classified into two types: a planar type and a vertical type.
There are two configurations. First, the surface conduction electron-emitting device will be described. FIG. 2 is a schematic view showing a configuration of a surface conduction electron-emitting device to which the present invention can be applied. FIG. 2A is a plan view, and FIG. 2B is a cross-sectional view.

In FIG. 2, 5 is a substrate, 9 and 10 are device electrodes, 6 is a thin film for forming an electron emitting portion, 7 is an electron emitting portion, 8
Is a thin film including an electron emitting portion. Examples of the substrate 1 include quartz glass, glass with a reduced content of impurities such as Na, blue plate glass, and Si formed on blue plate glass by sputtering or the like.
A glass substrate on which O ₂ is laminated, a ceramic such as alumina, a Si substrate, or the like can be used.

As a material for the element electrodes 9 and 10 facing each other, a general conductor material can be used. This includes, for example, Ni, Cr, Au, Mo, W, Pt, Ti, Al,
Metals or alloys such as Cu and Pd and Pd, Ag, Au, R
It can be appropriately selected from a printed conductor composed of a metal or a metal oxide such as uO ₂ or Pd-Ag and glass, a transparent conductor such as In ₂ O ₃ —SnO ₂ and a semiconductor material such as polysilicon. it can. Of these materials, platinum is preferably used in the present invention.

The element electrode interval L1, the element electrode length W1, and the shape of the thin film 6 for forming the electron emission portion are designed in consideration of the applied form and the like. The element electrode interval L1 can be preferably in the range of several thousand Angstroms to several hundred micrometers, and more preferably several micrometer to several tens micrometer in consideration of the voltage applied between the element electrodes. Range.

The element electrode length W1 can be set in a range from several micrometers to several hundred micrometers in consideration of the resistance value of the electrode and the electron emission characteristics. Device electrode 2,
The thickness d of 3 can be in the range of hundreds of angstroms to several micrometers.

It should be noted that not only the structure shown in FIG.
On top of this, the electron-emitting-portion-forming thin film 6, the opposing device electrode 9,
It is also possible to adopt a configuration in which the layers are stacked in the order of 10.

It is preferable to use a fine particle film composed of fine particles for the electron emitting portion forming thin film 6 in order to obtain good electron emission characteristics. It is appropriately set in consideration of the resistance between the device electrodes 9 and 10 and the energizing forming conditions described later, but is usually preferably in the range of several Å to several thousand Å, more preferably 10 ° to 500 °. Should be within the range. The resistance value of Rs is 10 ² to 10 ⁷ ohm / □. Rs is a resistance R of a thin film having a thickness t, a width w, and a length l.
Appears as R = Rs (l / w). In the present specification, the forming process will be described by taking an energizing process as an example, but the forming process is not limited to this, and includes any process that causes a crack in a film to form a high resistance state. Things.

The fine particle film described here is a film in which a plurality of fine particles are aggregated, and has a fine structure in a state where the fine particles are dispersed and arranged here, or in a state where the fine particles are adjacent to each other or overlap each other (when some fine particles are mixed). To form an island-like structure as a whole). The particle size of the microparticles ranges from a few Angstroms to several thousand Angstroms, preferably from 10 ° to 200 °.

In the present specification, the term “fine particles” is frequently used, and its meaning will be described.

Small particles are called "fine particles", and smaller ones are called "ultra fine particles". It is widely known that a particle having a size smaller than the "ultra-fine particles" and having a number of atoms of about several hundreds or less is referred to as a "cluster".

However, each boundary is not strict, and changes depending on what kind of property is focused on. Further, “fine particles” and “ultrafine particles” may be collectively referred to as “fine particles”, and the description in this specification is in line with this.

"Experimental Physics Course 14 Surface and Fine Particles"
(Edited by Kinoshita Yoshio, Kyoritsu Shuppan published September 1, 1986)
Then, it is described as follows. "When we say fine particles in this paper, the diameter is about 2-3 μm to 10n.
m, and especially when it is referred to as ultrafine particles, the particle size is 10
It means from about nm to about 2 to 3 nm. It is not exactly strict because both are collectively written as fine particles, but it is a rough guide. When the number of atoms constituting a particle is two to several tens to several hundreds, it is called a cluster. "(Page 195, lines 22 to 26)

In addition, the definition of “ultrafine particles” in the “Hayashi / Ultrafine Particle Project” of the New Technology Development Corporation has the following lower limit of the particle size, and is as follows.

In the “Ultrafine Particle Project” of the Promotion System for Creative Science and Technology (1981-1986), a particle having a particle size (diameter) in the range of about 1 to 100 nm is called “ultrafine particle”. Then, one ultrafine particle is about 100-
It comes to 10 ^{eight-position} of atoms aggregate of. Ultra-fine particles are large to giant particles on an atomic scale. ("Ultra Fine Particles-Creative Science and Technology-" Hayashi Tax, Ryoji Ueda, Akira Tazaki
Ed., Mita Publishing, 1988, page 2, lines 1 to 4) "A particle smaller than ultrafine particles, that is, a single particle composed of several to several hundred atoms is usually called a cluster." Lines 12-13).

[0063] Based on the general notation as described above,
In this specification, the term "fine particles" refers to an aggregate of a large number of atoms and molecules, and the lower limit of the particle diameter is about several Angstroms to about 10 Angstroms, and the upper limit is about several microns.

The electron emitting portion 7 is formed of the thin film 6 for forming the electron emitting portion.
Is formed by a high-resistance crack formed in a part of the thin film, and depends on the thickness, the film quality, the material of the thin film 6 for forming the electron emission portion, the method such as the energization forming described later, and the like. In some cases, conductive fine particles having a particle size in the range of several angstroms to several hundred angstroms are present inside the electron emission portion 7. The conductive fine particles contain some or all of the elements of the material constituting the conductive thin film 4. The electron emitting portion 7 and the electron emitting portion forming thin film 6 near the electron emitting portion 7 can also contain carbon and a carbon compound.

Next, a vertical surface conduction electron-emitting device will be described. FIG. 4 is a schematic diagram showing an example of a vertical surface conduction electron-emitting device to which the surface conduction electron-emitting device of the present invention can be applied.

In FIG. 4, the same parts as those shown in FIG. 2 are denoted by the same reference numerals. 41 is a step forming part. The substrate 5, the device electrodes 9 and 10, the electron-emitting-portion-forming thin film 6, and the electron-emitting portion 7 can be made of the same material as in the case of the above-mentioned flat surface conduction electron-emitting device. The step forming portion 41 can be made of an insulating material such as SiO ₂ formed by a vacuum evaporation method, a printing method, a sputtering method, or the like. The film thickness of the step forming portion 41 corresponds to the device electrode interval L1 of the above-mentioned flat surface conduction electron-emitting device, and can be in the range of several thousand angstroms to several tens of micrometers. This film thickness is set in consideration of the manufacturing method of the step forming portion and the voltage applied between the device electrodes, but is preferably in the range of several hundred angstroms to several micrometers.

After the formation of the step electrodes 41 and the device electrodes 9 and 10, the thin film 6 for forming the electron emission portions is removed.
It is laminated on. In FIG. 3, the electron emission section 7 is
Although formed in the step forming portion 31, the shape and position are not limited to these depending on the forming conditions, forming conditions and the like.

The basic characteristics of the electron-emitting device to which the present invention can be applied obtained through the above-described steps will be described with reference to FIGS.

FIG. 6 is a schematic view showing an example of a vacuum processing apparatus. This vacuum processing apparatus also has a function as a measurement and evaluation apparatus. 6, the same parts as those shown in FIG. 2 are denoted by the same reference numerals as those shown in FIG. In FIG. 6, reference numeral 65 denotes a vacuum vessel, and 66 denotes an exhaust pump. An electron-emitting device is provided in the vacuum vessel 65. That is, 5 is a substrate constituting the electron-emitting device, 9 and 10 are device electrodes, 7 is an electron-emitting portion, and 8 is a thin film including the electron-emitting portion. Reference numeral 61 denotes a power supply for applying a device voltage Vf to the electron-emitting device, and 60 denotes a device electrode 9.
Device current I flowing through the thin film 8 including the electron emission portion between −10
An ammeter 64 for measuring f is an anode electrode for capturing an emission current Ie emitted from the electron emission portion of the device. 63 is a high-voltage power supply for applying a voltage to the anode electrode 64, and 62 is an ammeter for measuring the emission current Ie emitted from the electron emission section 5 of the device. As an example, the voltage of the anode electrode is in the range of 1 kV to 10 kV, and the distance H between the anode electrode and the electron-emitting device is 2 mm to
Measurements can be made over a range of 8 mm.

In the vacuum vessel 65, devices necessary for measurement in a vacuum atmosphere such as a vacuum gauge (not shown) are provided.
Measurement and evaluation can be performed in a desired vacuum atmosphere. The exhaust pump 66 is composed of a normal high vacuum device system including a turbo pump and a rotary pump, and an ultrahigh vacuum device system including an ion pump and the like.
The entire vacuum processing apparatus provided with the electron source substrate shown here can be heated up to 200 degrees by a heater (not shown).
Therefore, when this vacuum processing apparatus is used, the steps after the above-described energization forming can also be performed.

FIG. 7 shows emission current Ie, device current If and device voltage Vf measured using the vacuum processing apparatus shown in FIG.
FIG. 5 is a diagram schematically showing the relationship of FIG. In FIG. 7, since the emission current Ie is significantly smaller than the device current If,
Shown in arbitrary units. Note that both the vertical and horizontal axes are linear scales.

As is apparent from FIG. 7, the surface conduction electron-emitting device to which the present invention can be applied has three characteristic characteristics with respect to the emission current Ie. That is, (i) this element has a certain voltage (referred to as threshold voltage, Vth in FIG. 7)
When the above element voltage is applied, the emission current Ie sharply increases, while the emission current Ie is hardly detected below the threshold voltage Vth. That is, it is a nonlinear element having a clear threshold voltage Vth with respect to the emission current Ie.
(Ii) Since the emission current Ie depends monotonically on the device voltage Vf, the emission current Ie can be controlled by the device voltage Vf.
(Iii) The emission charge captured by the anode electrode 64 is:
It depends on the time for applying the element voltage Vf. That is, the amount of charge captured by the anode electrode 64 can be controlled by the time during which the device voltage Vf is applied.

As understood from the above description, the surface conduction electron-emitting device to which the present invention can be applied can easily control the electron emission characteristics according to the input signal.
By utilizing this property, it is possible to apply to various fields such as an electron source and an image forming apparatus having a plurality of electron-emitting devices.

In FIG. 7, an example in which the element current If monotonically increases with respect to the element voltage Vf (hereinafter referred to as "MI characteristic") is shown by a solid line. The element current If may exhibit a voltage-controlled negative resistance characteristic (hereinafter, referred to as “VCNR characteristic”) with respect to the element voltage Vf (not shown). Further, these characteristics can be controlled by controlling the above-described steps.

Hereinafter, application examples of the electron-emitting device to which the present invention can be applied will be described. By arranging a plurality of surface conduction electron-emitting devices to which the present invention is applicable on a substrate, for example, an electron source or an image forming apparatus can be configured.

Various arrangements of the electron-emitting devices can be adopted. As an example, each of a large number of electron-emitting devices arranged in parallel is connected at both ends, a large number of rows of electron-emitting devices are arranged (referred to as a row direction), and a direction perpendicular to the wiring (referred to as a column direction). There is a ladder-like arrangement in which electrons from the electron-emitting devices are controlled and driven by control electrodes (also referred to as grids) disposed above the electron-emitting devices. Separately, a plurality of electron-emitting devices are arranged in rows and columns in the X and Y directions, and one of the electrodes of the plurality of electron-emitting devices arranged in the same row is commonly connected to a wiring in the X direction, and the same. One example is one in which the other of the electrodes of the plurality of electron-emitting devices arranged in a row is commonly connected to a wiring in the Y direction. This is a so-called simple matrix arrangement.

First, the simple matrix arrangement will be described in detail below. The surface conduction electron-emitting device to which the present invention can be applied has characteristics (i) to (iii) as described above. That is, when the electrons emitted from the surface conduction electron-emitting device are equal to or higher than the threshold voltage, they can be controlled by the peak value and the width of the pulse-like voltage applied between the opposing device electrodes. on the other hand,
Below the threshold voltage, it is hardly emitted. According to this characteristic, even when a large number of electron-emitting devices are arranged, if a pulse-like voltage is appropriately applied to each of the devices, a surface-conduction electron-emitting device is selected according to an input signal to emit electrons. You can control the amount.

Hereinafter, based on this principle, an electron source substrate obtained by disposing a plurality of electron-emitting devices to which the present invention can be applied will be described with reference to FIG. 8, 81 is an electron source substrate, 82 is an X-direction wiring, and 83 is a Y-direction wiring.
84 is a surface conduction electron-emitting device, and 85 is a connection.
The surface conduction electron-emitting device 84 may be of the above-mentioned flat type or vertical type.

The m X-direction wirings 82 are Dx1, Dx2,
... It is made of Dxm and can be made of a conductive metal or the like formed by a vacuum deposition method, a printing method, a sputtering method, or the like. The material, thickness, and width of the wiring are appropriately set. Y
The direction wiring 83 is composed of n wirings Dy1, Dy2,... Dyn, and is formed similarly to the X-direction wiring 82. An interlayer insulating layer (not shown) is provided between the m X-directional wirings 82 and the n Y-directional wirings 83 to electrically separate them (m and n are both Positive integer).

The interlayer insulating layer (not shown) is made of SiO ₂ or the like formed by using a vacuum deposition method, a printing method, a sputtering method, or the like. For example, it is formed in a desired shape on the entire surface or a part of the substrate 81 on which the X-directional wiring 82 is formed. The material and the production method are appropriately set. The X-direction wiring 82 and the Y-direction wiring 83 are led out as external terminals.

A pair of electrodes (not shown) constituting the surface conduction electron-emitting device 84 are electrically connected by m X-directional wirings 82, n Y-directional wirings 83, and a connection 85 made of a conductive metal or the like. It is connected.

The material forming the wiring 82 and the wiring 83, the material forming the connection 85, and the material forming the pair of element electrodes may be the same or different in some or all of the constituent elements. Good. These materials are appropriately selected, for example, from the above-described materials for the device electrodes. When the material forming the element electrode and the wiring material are the same, the wiring connected to the element electrode can also be called an element electrode.

The X-direction wiring 82 is connected to a scanning signal applying means (not shown) for applying a scanning signal for selecting a row of the surface conduction electron-emitting devices 84 arranged in the X direction. On the other hand, a modulation signal generating means (not shown) for modulating each column of the surface conduction electron-emitting devices 84 arranged in the Y direction according to an input signal is connected to the Y-direction wiring 83. The driving voltage applied to each electron-emitting device is supplied as a difference voltage between a scanning signal and a modulation signal applied to the device.

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

An image forming apparatus configured using such an electron source having a simple matrix arrangement will be described with reference to FIGS. 9, 10 and 11. FIG. 9 is a schematic diagram illustrating an example of a display panel of the image forming apparatus, and FIG. 10 is a schematic diagram of a fluorescent film used in the image forming apparatus of FIG. FIG.
FIG. 1 is a block diagram showing an example of a drive circuit for performing display according to an NTSC television signal.

In FIG. 9, reference numeral 81 denotes an electron source substrate on which a plurality of electron-emitting devices are arranged; 91, a rear plate on which the electron source substrate 81 is fixed; 96, a fluorescent film 94 on the inner surface of a glass substrate 93;
And a face plate on which a metal back 95 and the like are formed. Reference numeral 92 denotes a support frame, and a rear plate 91 and a face plate 96 are connected to the support frame 92 using frit glass or the like. Reference numeral 98 denotes an envelope, which is sealed by firing in air or nitrogen at a temperature range of 400 to 500 ° C. for 10 minutes or more.

Reference numeral 84 corresponds to the electron emission section 7 in FIG. Reference numerals 82 and 83 denote an X-direction wiring and a Y-direction wiring connected to a pair of device electrodes of the surface conduction electron-emitting device.

The envelope 98 comprises the face plate 96, the support frame 92, and the rear plate 91 as described above.
Since the rear plate 91 is provided mainly for the purpose of reinforcing the strength of the substrate 81, if the substrate 81 itself has sufficient strength, the separate rear plate 91 can be unnecessary. That is, the support frame 92 is directly sealed to the substrate 81, and the envelope 98
May be configured. On the other hand, by providing a support (not shown) called a spacer between the face plate 96 and the rear plate 91, the envelope 88 having sufficient strength against atmospheric pressure can be formed.

FIG. 10 is a schematic diagram showing a fluorescent film. The fluorescent film can be composed of only the phosphor 102 in the case of monochrome. In the case of a color fluorescent film, a black conductive material 101 called a black stripe or a black matrix and a fluorescent material 102 depending on the arrangement of the fluorescent materials are used.
And can be composed of The purpose of providing the black stripes and the black matrix is to make the mixed portions inconspicuous by making the painted portions between the phosphors 102 of the necessary three primary color phosphors black in color display, and to reduce the external light in the phosphor film. It is to suppress a decrease in contrast due to reflection. As a material for the black stripe, a material which is conductive and has little light transmission and reflection can be used in addition to a commonly used material mainly containing graphite.

The method of applying the fluorescent substance to the glass substrate 93 can employ a precipitation method, a printing method, or the like irrespective of monochrome or color. Usually, a metal back 9 is provided on the inner surface side of the fluorescent film 94.
5 are provided. The purpose of providing the metal back is to improve the brightness by mirror-reflecting the light toward the inner surface side of the phosphor emission toward the face plate 96 side, to act as an electrode for applying an electron beam acceleration voltage, The purpose is to protect the phosphor from damage due to collision of negative ions generated in the envelope. The metal back is
After the formation of the fluorescent film, the inner surface of the fluorescent film may be smoothed (usually called "filming"), and then aluminum may be deposited by vacuum evaporation or the like.

The face plate 96 is further provided with a fluorescent film 9.
A transparent electrode (not shown) may be provided on the outer surface side of the fluorescent film 94 in order to increase the conductivity of No. 4.

When performing the above-described sealing, in the case of color, it is necessary to make the phosphors of each color correspond to the electron-emitting devices, and sufficient alignment is indispensable.

The image forming apparatus shown in FIG. 9 is manufactured, for example, as follows.

[0094] The envelope 88, similar to the aforementioned stabilization step, while being heated appropriately, ion pump, by an exhaust device not using oil, such as a sorption pump evacuated through an exhaust pipe (not shown), 10 ^-7 After the atmosphere is made sufficiently low in the organic substance with a degree of vacuum of about Torr, sealing is performed. In order to maintain the degree of vacuum after sealing the envelope 98, a getter process may be performed. This is the envelope 98
Immediately before or after sealing, a getter disposed at a predetermined position (not shown) in the envelope 98 is heated by heating using resistance heating, high-frequency heating, or the like to form a deposition film. Processing. The getter is usually composed mainly of Ba or the like.
The vacuum degree of 0 ^-5 or 1 × 10 ^-7 Torr is maintained. Here, steps after the forming process of the surface conduction electron-emitting device can be appropriately set.

Next, an example of the configuration of a driving circuit for performing television display based on NTSC television signals on a display panel configured using electron sources in a simple matrix arrangement will be described with reference to FIG. . 11, reference numeral 111 denotes an image display panel; 112, a scanning circuit;
3 is a control circuit, and 114 is a shift register. 115
Is a line memory, 116 is a synchronization signal separation circuit, 117 is a modulation signal generator, and Vx and Va are DC voltage sources.

The display panel 111 is connected to an external electric circuit via terminals Dox1 to Doxm, terminals Doy1 to Doyn, and a high voltage terminal Hv. Terminal Do
x1 to Doxm are used to sequentially drive electron sources provided in the display panel, that is, a group of surface conduction electron-emitting devices arranged in a matrix of M rows and N columns, one row (N elements) at a time. A scanning signal is applied.

A modulation signal for controlling the output electron beam of each of the surface conduction electron-emitting devices in one row selected by the scanning signal is applied to the terminals Dy1 to Dyn. The high voltage terminal Hv is supplied with a DC voltage of, for example, 10 K [V] from a DC voltage source Va, which is sufficient to excite the phosphor into an electron beam emitted from the surface conduction electron-emitting device. It is an accelerating voltage for applying energy.

The scanning circuit 112 will be described. This circuit includes M switching elements (schematically indicated by S1 to Sm in the figure). Each switching element selects either the output voltage of the DC voltage source Vx or 0 [V] (ground level),
It is electrically connected to terminals Dx1 to Dxm of the display panel 111. Each of the switching elements S1 to Sm is
It operates based on a control signal Tscan output from the control circuit 113, and can be configured by combining switching elements such as FETs, for example.

In the case of the present embodiment, the DC voltage source Vx is based on the characteristics of the surface conduction type electron-emitting device (electron emission threshold voltage), and the driving voltage applied to the unscanned device is the electron emission threshold. It is set to output a constant voltage that is equal to or lower than the value voltage.

The control circuit 113 has a function of matching the operation of each unit so that appropriate display is performed based on an image signal input from the outside. The control circuit 113 transmits Tscan, Tsft, and T to each unit based on the synchronization signal Tsync sent from the synchronization signal separation circuit 116.
mry control signals are generated.

The synchronizing signal separating circuit 116 is a circuit for separating a synchronizing signal component and a luminance signal component from an NTSC television signal input from the outside, and uses a general frequency separating (filter) circuit or the like. Can be configured. The synchronizing signal separated by the synchronizing signal separating circuit 116 includes a vertical synchronizing signal and a horizontal synchronizing signal, but is illustrated here as a Tsync signal for convenience of explanation. The luminance signal component of the image separated from the television signal is referred to as a DATA signal for convenience. The DATA signal is input to the shift register 114.

The shift register 114 is for serially / parallel converting the DATA signal input serially in time series for each line of an image, and is based on a control signal Tsft sent from the control circuit 113. (Ie, the control signal Tsft can be said to be a shift clock of the shift register 114).
The data for one line of the serial / parallel-converted image (corresponding to drive data for N electron-emitting devices) is Id
It is output from the shift register 114 as N parallel signals of 1 to Idn.

The line memory 115 is a storage device for storing data for one line of an image for a required time only, and stores the contents of Id1 to Idn as appropriate according to a control signal Tmry sent from the control circuit 113. The stored contents are output as I'd1 to I'dn,
The signal is input to the modulation signal generator 117.

The modulation signal generator 117 is a signal source for appropriately driving and modulating each of the surface-driven electron-emitting devices in accordance with each of the image data I'd1 to I'dn. Is applied to the surface conduction electron-emitting devices in the display panel 111 through the terminals Doy1 to Doyn.

As described above, the electron-emitting device to which the present invention can be applied has the following basic characteristics with respect to the emission current Ie. That is, a clear threshold voltage Vth is required for electron emission.
And electron emission occurs only when a voltage higher than Vth is applied. For a voltage equal to or higher than the electron emission threshold, the emission current also changes according to the change in the voltage applied to the device. From this, when applying a pulsed voltage to this element,
For example, when a voltage lower than the electron emission threshold is applied, electron emission does not occur. However, when a voltage at the electron emission threshold is applied, an electron beam is output. At this time, the intensity of the output electron beam can be controlled by changing the pulse peak value Vm. Further, by changing the pulse width Pw, it is possible to control the total amount of charges of the output electron beam.

Therefore, as a method of modulating the electron-emitting device in accordance with the input signal, a voltage modulation method, a pulse width modulation method, or the like can be adopted. When implementing the voltage modulation method, a circuit of a voltage modulation method that generates a voltage pulse of a fixed length and modulates the peak value of the pulse appropriately according to input data is used as the modulation signal generator 117. be able to.

When implementing the pulse width modulation method,
As the modulation signal generator 117, a pulse width modulation type circuit that generates a voltage pulse having a constant peak value and appropriately modulates the width of the voltage pulse according to input data can be used.

The shift register 114 and the line memory 11
5 can be a digital signal type or an analog signal type. This is because the serial / parallel conversion and storage of the image signal may be performed at a predetermined speed.

When the digital signal type is used, it is necessary to convert the output signal DATA of the synchronizing signal separating circuit 116 into a digital signal. This can be achieved by providing an A / D converter at the output of the synchronizing signal separating circuit 116. In connection with this, the line memory 115
The circuit used for the modulation signal generator 117 differs slightly depending on whether the output signal is a digital signal or an analog signal. That is, in the case of the voltage modulation method using a digital signal, for example, a D / A conversion circuit is used as the modulation signal generator 117, and an amplification circuit and the like are added as necessary. In the case of the pulse width modulation method, the modulation signal generator 117 includes, for example, a high-speed oscillator, a counter for counting the number of waves output from the oscillator, and a comparison for comparing the output value of the counter with the output value of the memory. Use a circuit that combines a device (comparator). If necessary, an amplifier for amplifying the voltage of the pulse width modulated signal output from the comparator to the drive voltage of the surface conduction electron-emitting device can be added.

In the case of the voltage modulation method using an analog signal, for example, an amplification circuit using an operational amplifier or the like can be used as the modulation signal generator 117, and a level shift circuit or the like can be added as necessary. In the case of the pulse width modulation method, for example, a voltage-controlled oscillation circuit (VCO) can be adopted, and an amplifier for amplifying the voltage up to the drive voltage of the surface conduction electron-emitting device can be added if necessary.

In the image display apparatus to which the present invention can be applied in such a configuration, the external terminals Dox1 to Doxm, Doy1 to Doy are provided to each electron-emitting device.
By applying a voltage through n, electron emission occurs. A high voltage is applied to the metal back 95 or a transparent electrode (not shown) via the high voltage terminal Hv to accelerate the electron beam. The accelerated electrons collide with the fluorescent film 94 and emit light to form an image.

The configuration of the image forming apparatus described here is an example of an image forming apparatus to which the present invention can be applied, and various modifications can be made based on the technical idea of the present invention. Although the NTSC system has been used as the input signal, the input signal is not limited to the NTSC system. In addition to the PAL and SECAM systems, a TV signal including a larger number of scanning lines (for example, the MUSE system, etc.) High-definition TV).

Next, the ladder-shaped arrangement of the electron source and the image forming apparatus will be described with reference to FIGS.

FIG. 12 is a schematic view showing an example of a ladder-type electron source. In FIG. 12, reference numeral 120 denotes an electron source substrate, and 121 denotes an electron-emitting device. 122 (Dx1-D
x10) is a common wiring for connecting the electron-emitting devices 121. The electron-emitting device 121 is provided on the substrate 120.
A plurality are arranged in parallel in the X direction (this is called an element row). A plurality of the element rows are arranged to constitute an electron source. By applying a drive voltage between the common lines of each element row, each element row can be driven independently. That is,
A voltage equal to or higher than the electron emission threshold is applied to an element row that wants to emit an electron beam.
A voltage lower than the electron emission threshold is applied. For the common wirings Dx2 to Dx9 between the element rows, for example, Dx2 and Dx3 may be the same wiring.

FIG. 13 is a schematic diagram showing an example of a panel structure in an image forming apparatus having a ladder-type electron source. 130 is a grid electrode, 131 is a hole through which electrons pass, 132 is Dox1, Dox2,.
xm. Reference numeral 133 denotes an external terminal composed of G1, G2,... Gn connected to the grid electrode 130, and reference numeral 134 denotes an electron source substrate in which the common wiring between the element rows is the same. In FIG. 13, FIGS.
Are given the same reference numerals as those shown in these figures. The major difference between the image forming apparatus shown here and the image forming apparatus having the simple matrix arrangement shown in FIG.
Is provided with the grid electrode 130 between them.

In FIG. 13, a grid electrode 130 is provided between the substrate 120 and the face plate 96. The grid electrode 130 is for modulating the electron beam emitted from the surface conduction electron-emitting device,
In order to allow an electron beam to pass through stripe-shaped electrodes provided orthogonally to the ladder-shaped element rows, one circular opening 131 is provided for each element. The shape and installation position of the grid are not limited to those shown in FIG. For example, a large number of passage openings may be provided in a mesh shape as openings, and a grid may be provided around or near the surface conduction electron-emitting device.

The outer container terminal 132 and the grid outer terminal 133 are electrically connected to a control circuit (not shown).

In the image forming apparatus of this embodiment, a modulation signal for one line of an image is simultaneously applied to the grid electrode rows in synchronization with sequentially driving (scanning) the element rows one by one. This makes it possible to control the irradiation of each electron beam to the phosphor and display an image one line at a time.

The image forming apparatus of the present invention is used not only as a display device for a television broadcast, a display device such as a video conference system or a computer, but also as an image forming device as an optical printer using a photosensitive drum or the like. You can also.

[0120]

EXAMPLES Examples of the present invention will be described below.
The present invention is not limited to the following examples. Implementation
Example 1 A quartz substrate was used as the insulating layer substrate 5, and after sufficiently washing with an organic solvent, device electrodes 9 and 10 were formed on the surface of the substrate 5 (FIG. 3A). Pt metal was used as a material for this electrode. The electrode interval L1 is 2 μm,
The length of the electrode (in the depth direction of the paper) was 500 μm, and its thickness was 1000 °. As the platinum etching solution, a solution prepared by diluting aqua regia with water and adding 2% by weight of sodium chloride was used. The time required for etching was 70 seconds.

Droplets were applied to the device electrodes 9 and 10 by a bubble jet method. That is, a 0.1% by weight aqueous solution of palladium acetate was used as a raw material for the electron emission film, and was injected from a nozzle by a valve jet method.

The manufacturing apparatus used here is entirely depressurized and cooled. The pressure was 0.5 atm and the temperature was 2 ° C. This lowers the boiling point of water by about 20 ° C. The heater temperature of the bubble jet was set to about 20 ° C. lower than the conventional temperature by electric adjustment. As a result, the amount of pyrolysis was reduced as compared with the conventional case. Further, the discharge amount and the discharge speed were satisfactory.

Next, the pressure reducing device and the cooler of the manufacturing apparatus were stopped, the airtight chamber was opened, and the pressure was returned to normal pressure and normal temperature. Next, low-temperature heating (100 ° C. or lower) was performed to generate a metal fine particle film and a low-temperature volatile substance. Next, heating was performed in air at 200 ° C. for 20 minutes to volatilize and remove low-temperature volatile substances, thereby forming metal fine particle films. Further, heating was performed at 300 ° C. for 10 minutes.

The amount of palladium in the formed film was determined by plasma emission spectroscopy.
It was 7.0 μg / cm ² . The thickness was measured by an atomic force microscope and found to be 105 °, an increase of about 5% as compared with Comparative Example 1 described later. The variation in the film thickness was about 9/10 as compared with Comparative Example 1. Next, an electric current was applied to produce an electron emission film. Table 1 shows the obtained results.

[0125] The manufacturing process of Example 2 Example 2 will be described with reference to FIG. Using an aqueous solution of palladium acetate as a raw material for forming an electron emission film, a thin film 6 made of palladium oxide fine particles (average particle size: 58 °) was formed on the insulating layer substrate 5 in the same manner as in Example 1. Here, the length (in the depth direction of the paper) of the fine particle film 6 was set to 300 μm, and it was disposed almost at the center of the electrodes 9 and 10 (FIG. 3B).

Next, a voltage was applied between the electrode 9 and the electrode 10, and the fine particle film 6 was subjected to an energization process (forming process) to form an electron emission region 7 (FIG. 3C).
FIG. 5 shows a voltage waveform of the forming process.

In FIG. 5, T1 and T2 are the pulse width and pulse interval of the voltage waveform. In this embodiment, T1 is 1.0 millisecond and T2 is 10 milliseconds. The forming process was performed in a vacuum atmosphere of about 1 × 10 ⁻⁸ Torr.

In the above process, 500 similar devices were manufactured, and the electron emission characteristics were measured using the evaluation apparatus shown in FIG. FIG. 6 shows a schematic configuration diagram of the measurement evaluation apparatus. FIG.
, 5 is an insulating substrate, 9 and 10 are device electrodes, 8
Denotes a thin film including an electron emitting portion, and 7 denotes an electron emitting portion. 61
Is a power supply for applying a voltage to the element, and 60 is an element current I
an ammeter for measuring f; 64, an anode electrode for measuring an emission current Ie generated from the element; 63, a high-voltage power supply for applying a voltage to the anode electrode 64; 62, for measuring the emission current. It is an ammeter. Here, the element current is a current amount measured by the ammeter 60, and the emission current is a current amount measured by the ammeter 62.

In measuring the device current and emission current of the electron-emitting device, a power source 62 and an ammeter 60 are connected to the device electrodes 9 and 10, and a power source 63 and an ammeter 62 are connected above the electron-emitting device. The connected anode electrode 64 is arranged.

The electron-emitting device and the anode 6
Numeral 4 is installed in a vacuum device, and the vacuum device is provided with equipment necessary for a vacuum device such as an exhaust pump (not shown) and a vacuum gauge, and can perform measurement and evaluation of the element under a desired vacuum. It has become so.

In this embodiment, the distance between the anode and the electron-emitting device is 4 mm, and the potential of the anode is 1K.
V, the degree of vacuum in the vacuum device when measuring the electron emission characteristics is
It was set to 0 ^-7 torr.

Using the above-described measurement and evaluation apparatus, a device voltage is applied between the electrodes 9 and 10 of the electron-emitting device.
The device current If and emission current Ie flowing at that time were measured. In this device, the emission current Ie rapidly increases from a device voltage of about 8 V, and when the device voltage is 14 V, the device current If becomes 2.
2 mA, the emission current Ie was 1.1 μA, and the electron emission efficiency η = Ie / If (%) was 0.05.

Example 3 In this example, an image forming apparatus was manufactured using the electron-emitting devices manufactured in the same manner as in Example 2. 9 and 10
This will be described below with reference to FIG.

After fixing the substrate 81 on which the electron-emitting device was fabricated as in Example 2 on the rear plate 91, the face plate 96 (the fluorescent film 94 and the metal The back plate 95 is formed via a support frame 92, and frit glass is applied to a joint between the face plate 96, the support frame 92, and the rear plate 91. Sealing was performed by baking at 500 to 500 ° C. for 10 minutes or more (FIG. 7). The fixing of the substrate 81 to the rear plate 91 was also performed using frit glass. In FIG. 9, reference numeral 84 denotes an electron-emitting portion, and reference numerals 82 and 83 denote device electrodes in the X and Y directions, respectively. The number of elements at this time was 16 rows and 16 columns, that is, 256 elements.

As described above, the outer casing 98 is constituted by the face plate 96, the support frame 92, and the rear plate 91. However, since the rear plate 97 is provided mainly for the purpose of reinforcing the strength of the board 81, the board 81 itself is not provided. In this case, a separate rear plate 91 is unnecessary, and the support frame 92 is directly sealed on the substrate 81 to form the face plate 9.
6, the outer frame 98 may be composed of the support frame 92 and the substrate 81. The fluorescent film 94 is made of only a phosphor in the case of monochrome, but is composed of a black conductive material 101 called a black stripe or a black matrix and a phosphor 102 depending on the arrangement of the phosphor in the case of a color fluorescent film. (FIG. 10). The purpose of providing the black stripes and the black matrix is to make the mixed portions of the three primary color phosphors necessary for color display less inconspicuous by making the coating portion between the respective phosphors 102 black, and The purpose is to suppress a decrease in contrast due to external light reflection. In the present embodiment, the fluorescent material adopted a stripe shape, a black stripe was formed first, and the fluorescent material of each color was applied to the gap between the black stripes. As the material for the black stripe, a material mainly containing graphite, which is generally used, is used. However, the material is not limited to this as long as it is conductive and has little light transmission and reflection.

As a method of applying a phosphor onto the glass substrate 93, a precipitation method or a printing method is used in the case of monochrome, but in the present embodiment, which is a color method, a slurry method is used.
Even in the case of color printing, the same coating film can be obtained by using the printing method.

Further, the light to the inner surface of the fluorescent film 94 is specularly reflected toward the face plate 96 to improve the brightness, to function as an electrode for applying an electron beam accelerating voltage, Acts as a protective film of the phosphor from the damage caused by the collision of the negative ions generated in the above.

The metal back 95 was manufactured by performing a smoothing process (usually called filtering) on the inner surface of the fluorescent film after the fluorescent film was manufactured, and then performing vacuum deposition of aluminum. The face plate 96 may be provided with a transparent electrode (not shown) on the outer surface side of the fluorescent film 94 in order to further increase the conductivity of the fluorescent film 94, but in this embodiment, only the metal back 95 is sufficient. Omitted because conductivity was obtained. When the above-mentioned sealing was performed, in the case of color, sufficient alignment was performed because each color phosphor and the electron-emitting device had to correspond.

As described above, the atmosphere in the completed glass container is evacuated by a vacuum pump through an exhaust pipe (not shown), and after reaching a sufficient degree of vacuum, the external terminals Dx1 to Dx16 and Dx1 to Dx1 to Dx1 to Dx16. The device electrode 8 through Dx16
A voltage was applied between 2 and 83, and the above-described forming was performed to form an electron-emitting portion 84, thereby producing an electron-emitting device.

Finally, the exhaust pipe (not shown) was welded by heating with a gas burner at a degree of vacuum of about 10 ^-6 Torr, and the outer package was sealed.

Finally, in order to maintain the degree of vacuum after sealing,
Getter processing was performed. This is a process of heating a getter disposed at a predetermined position (not shown) in an image display device by a heating method such as resistance heating or high-frequency heating immediately before or after sealing to form a vapor-deposited film. It is. The getter usually contains Ba or the like as a main component, and maintains the degree of vacuum by the adsorption action of the deposited film.

In the image display device of the present invention completed as described above, each of the electron-emitting devices emits electrons by applying a voltage to the electron-emitting devices through external terminals Dx1 to Dx16 and Dx1 to Dx16. , A high voltage of several kV or more was applied to a metal back 95 or a transparent electrode (not shown) to accelerate the electron beam, collided with the fluorescent film 94, and excited and emitted light to display an image.

The configuration described above is a schematic configuration necessary for manufacturing an image display device. For example, detailed portions such as materials of each member are not limited to those described above. The arrangement form of the emission elements 94 on the substrate 81 may be a form in which a plurality of element rows in which a plurality of electron emission elements are connected between a pair of wiring electrodes are arranged. A control electrode (usually called a grid) for selecting an element that causes the phosphor to emit light is arranged in a direction perpendicular to the direction of the arrow. As described above, the selection is appropriately made so as to be suitable for the use of the image display device.

Comparative Example 1 Pt metal was used as the material of the device electrode. Electrode spacing L
1 is 2 μm, and the length of the electrode (in the depth direction of the paper) is 500
μm, and the thickness was 1000 °. As an etching solution for platinum, aqua regia was diluted twice with water and used without adding sodium chloride. The time required for etching was 90 seconds.

The raw material solution was a 0.1% by weight aqueous solution of palladium acetate in the same manner as in Example 1, and a bubble jet type manufacturing apparatus placed in a room at normal pressure and normal temperature was used.
Sprayed.

Otherwise, 500 electron-emitting devices were manufactured in exactly the same manner as in Example 2. In this case, as a result of quantifying the amount of palladium by plasma emission spectroscopy, Pd was 16.0 μg / cm ² . The film thickness was measured by an atomic force microscope and found to be 100 °. Table 1 shows the obtained results.

[0147]

[Table 1] (Note) The variation in the film thickness is the difference between the average of the first three substrates and the average of the last three substrates when 30 substrates (1 × 1.5 inches) are manufactured.

As is clear from the results of the examples and comparative examples, the method of the present invention makes the production atmosphere of the thin film for forming the electron-emitting portion at a pressure lower than the normal pressure and / or a temperature lower than the normal temperature. A thin film was obtained. In addition, it was possible to reduce the variation in the electron emission characteristics between the obtained electron-emitting devices, thereby obtaining an image forming apparatus with less variation in the element characteristics.

Further, by adding alkali metal ions to the etching solution for the platinum element electrode, the etching time was shortened and stabilized.

[0150]

As described above, according to the present invention,
By using a solution containing at least one metal ion selected from alkali metals in aqua regia as an etching solution for a platinum material such as a platinum electrode or a platinum electron-emitting portion, the required etching time can be reduced, and the required etching time can be reduced. It can be stabilized, and the quality of the member using the platinum material is stabilized. Further, the quality of the thin film and the electron-emitting device formed by applying a droplet over or between the platinum materials is also stabilized.

Further, as a method for producing a thin film for forming an electron-emitting portion, the production atmosphere is set to a pressure lower than normal pressure and / or a temperature lower than normal temperature, so that a decrease in the film thickness of the obtained thin film is suppressed, and device characteristics are reduced. Thus, it is possible to obtain an electron-emitting device, an electron source, a display device, and an image forming apparatus with less variation.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating a method for manufacturing an electron emission film of the present invention.

FIG. 2 is a schematic plan view and a cross-sectional view illustrating a configuration of a surface conduction electron-emitting device to which the present invention can be applied.

FIG. 3 is a process chart showing an example of a method for manufacturing an electron-emitting device of the present invention.

FIG. 4 is a schematic diagram showing a configuration of a vertical surface conduction electron-emitting device to which the present invention can be applied.

FIG. 5 is a schematic diagram showing an example of a voltage waveform in a current forming process that can be employed in manufacturing a surface conduction electron-emitting device to which the present invention can be applied.

FIG. 6 is a schematic diagram illustrating an example of a vacuum process having a measurement evaluation function.

FIG. 7 shows emission current Ie, device current If, and device voltage Vf for a surface conduction electron-emitting device applicable to the present invention.
6 is a graph showing an example of the relationship.

FIG. 8 is a schematic diagram showing an example of an electron source arranged in a simple matrix to which the present invention can be applied.

FIG. 9 is a schematic diagram illustrating an example of a display panel of an image forming apparatus to which the present invention can be applied.

FIG. 10 is a schematic diagram illustrating an example of a fluorescent film.

FIG. 11 is a block diagram showing an example of a driving circuit for performing display on an image forming apparatus in accordance with an NTSC television signal.

FIG. 12 is a schematic view showing an example of an electron source having a ladder arrangement to which the present invention can be applied.

FIG. 13 is a schematic diagram illustrating an example of a display panel of an image forming apparatus to which the present invention can be applied.

FIG. 14 is a schematic view showing an example of a conventional surface conduction electron-emitting device.

[Explanation of symbols]

1: Bubble jet type electron emission film manufacturing apparatus, 2: decompression device, 3: cooling device, 4: airtight chamber, 5: substrate, 6: thin film for forming electron emission portion, 7: electron emission portion, 8: electron emission portion 9, 10: element electrode, 41: step forming portion, 6
0: ammeter for measuring the device current If flowing through the thin film 8 including the electron-emitting portion between the device electrodes 9, 10; 61: power supply for applying the device voltage Vf to the electron-emitting device; 62:
An ammeter for measuring an emission current Ie emitted from the electron emission portion 5 of the device; 63: a high voltage power supply for applying a voltage to the anode electrode 64; 64: an emission current Ie emitted from the electron emission portion of the device An anode electrode for capturing the
65: vacuum device, 66: exhaust pump, 81: electron source substrate, 82: X direction wiring, 83: Y direction wiring, 84: surface conduction electron-emitting device, 85: connection, 91: rear plate, 92: support frame , 93: glass substrate, 94: fluorescent film,
95: metal back, 96: face plate, Hv:
High voltage terminal, 98: envelope, 101: black conductive material, 10
2: phosphor, 111: display panel, 112: scanning circuit,
113: control circuit, 114: shift register, 115:
Line memory, 116: synchronization signal separation circuit, 117: modulation signal generator, Vx and Va: DC voltage source, 120: electron source substrate, 121: electron emission element, 122, Dx1 to Dx
x10: common wiring for wiring the electron-emitting devices 121, 130: grid electrode, 131: holes for passing electrons, 132, Dox1 to Doxm: common wiring 12
2, external terminals 133, G1 to Gn: external terminals connected to the grid electrode 130.

Claims (10)

[Claims] An electron-emitting portion is formed through a step of partially applying a droplet of a metal compound solution containing an electron-emitting material between opposed electrodes, a heating and firing step, an etching step, and a step of conducting electricity. The etching liquid used in the etching step contains at least one metal ion selected from sodium, potassium, lithium, cesium and rubidium in the aqua regia. Manufacturing method. 2. The method for manufacturing an electron-emitting device according to claim 1, wherein a manufacturing atmosphere of the electron-emitting device is reduced and / or cooled. 3. The method according to claim 2, wherein the manufacturing atmosphere is less than 1 atm to 0.1 atm. 4. The method for manufacturing an electron-emitting device according to claim 2, wherein the manufacturing atmosphere is at 20 ° C. to 1 ° C. 5. A liquid jet apparatus according to claim 1, wherein said droplet applying means is of a bubble jet (registered trademark) type.
The method for manufacturing an electron-emitting device according to any one of the above. 6. The method according to claim 1, wherein the electron-emitting device is a surface conduction electron-emitting device. 7. A method for manufacturing an electron source comprising an electron-emitting device and a means for applying a voltage to the device, wherein the electron-emitting device is manufactured by the method according to claim 1. A method for manufacturing an electron source, comprising: 8. A method for manufacturing a display device comprising: an electron-emitting device, an electron source including a voltage applying means for the device, and a luminous body that receives and emits electrons emitted from the device. 7. The electron-emitting device according to claim 1, wherein
A method for manufacturing a display element, wherein the display element is manufactured by the method described in (1). 9. An electron source including an electron-emitting device and a voltage applying means for the device, a luminous body that emits light by receiving electrons emitted from the device, and a voltage applied to the device based on an external signal. 13. A method for manufacturing an image forming apparatus, comprising: a driving circuit for controlling the electron emission device, wherein the electron-emitting device is manufactured by the method according to claim 7. . 10. An etching solution for dissolving platinum used in a manufacturing process of an electron-emitting device, wherein the aqua regia contains at least one metal ion selected from sodium, potassium, lithium, cesium and rubidium. Etchant for platinum materials.