JP2000251660A - Manufacture of electron source and manufacture of image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron source, wherein each electron emission element has a uniform electron emission characteristic by forming uniform electron emission parts throughout almost all the electron emission elements, when current-carrying forming is performed to a conductive film of each of the electron emission elements in forming the multiple electron emission elements on a substrate having a large area. SOLUTION: When current-carrying forming is performed, an inactive gas such as He and N2 is first introduced so that the pressure inside a vacuum chamber 133 is kept constant. Next, an electron source substrate 71 is heated, and a voltage is applied to element electrodes on the electron source substrate 71. While the pressure inside vacuum chamber 133 is kept constant, a reductive or coagulating gas such as H2 is introduced.

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 source and a method of manufacturing an image forming apparatus having the electron source, and more particularly to an electron source having a surface conduction electron-emitting device. .

[0002]

2. Description of the Related Art Conventionally, two types of electron-emitting devices using a thermionic electron-emitting device and a cold-cathode electron-emitting device have been known. The cold cathode electron-emitting devices include a field emission type (hereinafter, referred to as “FE type”), a metal / insulating layer / metal type (hereinafter, referred to as “MIM type”), a surface conduction electron-emitting device, and the like. Examples of surface conduction electron-emitting devices include MI Elinson, Recio Eng. Electron Phys., 10,
1290, (1965). Surface-conduction electron-emitting devices consist of a small-area thin film formed on a substrate,
This utilizes the phenomenon that electron emission occurs when a current flows in parallel to the film surface. JP-A-7-235255 discloses a surface conduction electron-emitting device using a metal thin film such as Pd.

This surface conduction electron-emitting device is composed of a pair of device electrodes formed on a substrate 1 so as to face each other, and a conductive film made of a metal oxide thin film such as Pd formed between the device electrodes. The conductive film is locally destroyed, deformed, or altered by an energization process called energization forming, which will be described later, to form an electron emission portion in an electrically high resistance state.

Further, in order to improve the electron emission characteristics, a process called “activation” is performed as described later, and a film (carbon film) made of carbon / carbon compound is formed in and near the electron emission portion. There are cases. This step can be performed by applying a pulse voltage to the device in an atmosphere containing an organic substance and depositing carbon / carbon compound around the electron-emitting portion.

The above-mentioned surface conduction electron-emitting device has an advantage that a large number of devices over a large area can be arrayed because the structure is simple and the production is easy. Therefore, various applications that make use of this feature are being studied. For example, a charged beam source, a display device, and the like can be given. As an example in which a large number of surface conduction electron-emitting devices are arranged and formed, as will be described later, surface conduction electron-emitting devices are arranged in parallel, and both ends of each device are connected by wiring (also referred to as common wiring). An electron source in which a large number of such rows are arranged (for example, JP-A-64-31332, JP-A-1-228)
3749, 2-257552, etc.).

In recent years, in image forming apparatuses such as display apparatuses, flat panel display apparatuses using liquid crystals have been widely used in place of CRTs. However, since they are not self-luminous, they must have a backlight. Therefore, development of a self-luminous display device has been desired. An example of the self-luminous display device is an image forming device, which is a display device in which an electron source having a large number of surface conduction electron-emitting devices and a phosphor that emits visible light by electrons emitted from the electron source are combined. (Eg, US Pat. No. 5,066,883).

[0007]

In the forming step of forming the electron-emitting portion, a voltage is applied to the conductive film, and then the conductive film is mixed with a reducing gas such as hydrogen or a cohesive gas into the atmosphere. Done.

The conductive film is a film made of a thin film of a metal oxide such as Pd. The energization forming, which will be described later, is performed by locally destructing, deforming, or altering the conductive film by thermally aggregating it, thereby forming an electron emitting portion in the conductive film in an electrically high-resistance state. is there.

In the energization forming, an energization and heat generation action in which a current flows and heat is generated by applying a voltage to the conductive film;
The metal oxide constituting the conductive film is reduced by the reducing gas,
The effect of improving electrical conductivity by being reduced to metal is synergistically occurring.

A reducing gas such as hydrogen also has a coagulation effect, and the effect becomes more pronounced as the temperature increases.

Accordingly, since reduction / aggregation of the conductive film is accelerated by increasing the temperature of the substrate on which the conductive film is formed, the substrate temperature is raised to such an extent that the conductive film is not reduced / agglomerated. In this state, energization forming can be performed. This makes it possible to reduce the voltage value applied at the time of energization forming, to reduce the width of the destruction region of the electron emission portion formed by the forming, and to favorably perform the subsequent activation step of forming an electron source. be able to.

Further, the reduction reaction of the conductive film is affected by the atmosphere in which the energization forming is performed. For example, when a gas component such as water or oxygen is contained in the atmosphere, or when such a gas component is adsorbed on the surface of the conductive film, the reduction reaction by the reducing gas is hindered, and it takes time for the energization forming. This has such an effect. In order to prevent this effect, the substrate has been kept in a vacuum atmosphere before forming. Heating the substrate during energization forming is also effective in effectively removing gas components adsorbed on the substrate surface.

Further, forming is performed after forming an envelope in which a substrate and a face plate are joined with a frame material interposed therebetween. In the case of a flat panel display device, a large-area substrate is formed by reducing the thickness. Since it is sandwiched between thin support frames, it is difficult to remove the adsorbed gas components inside, and it is difficult to maintain the uniformity of the reducing gas introduced at the time of forming. There has been a problem that the form tends to vary.

Therefore, when forming is performed in a vacuum chamber, the substrate is generally placed on a heating stage such as a hot plate in order to heat the substrate, and the substrate is subjected to heat conduction between the heating stage and the substrate. Heated by radiation.

In the energization forming, since the reducing gas is introduced from a state where the substrate is heated in a vacuum atmosphere, the vacuum pressure is increased. At this time, since a large difference occurs in heat conduction between the substrate and a heating stage for heating the substrate, the temperature of the substrate increases during the energization forming.

In particular, when the substrate has a large area having a matrix wiring and a correspondingly large number of element electrodes and conductive films, the temperature rise value during the energization forming differs depending on the location on the substrate surface. In addition, there is a problem that a non-uniform distribution is generated in a temperature at which a crack is generated by forming, so that uniform forming cannot be performed.

Accordingly, an object of the present invention is to form a large number of electron-emitting devices on a large-area substrate and to form a uniform film over almost all of the electron-emitting devices when conducting forming the conductive film of each electron-emitting device. Method of manufacturing an electron source capable of realizing an electron source having uniform electron emission characteristics by forming a uniform electron emission portion, and forming an image having uniform luminance characteristics provided with the electron source An object of the present invention is to provide a method for manufacturing a device.

[0018]

According to a method of manufacturing an electron source of the present invention, a method of manufacturing an electron source in which a plurality of electron-emitting devices having a conductive film between a pair of electrodes are formed on a substrate is performed. A manufacturing method for performing a forming process for forming an electron-emitting portion on a conductive film, wherein a step of introducing an inert gas to a predetermined pressure in a vacuum device and a step of heating the substrate in the vacuum device And a step of applying a voltage between the electrodes to perform the forming treatment, and a step of mixing a reducing or aggregating gas with the inert gas while keeping the pressure in the vacuum device constant. .

In one embodiment of the method for producing an electron source according to the present invention, the reducing gas is hydrogen.

In one embodiment of the method for manufacturing an electron source according to the present invention, the inert gas is helium or nitrogen.

In one embodiment of the method of manufacturing an electron source according to the present invention, the pressure in the vacuum device is 1 Torr or more.

According to a method of manufacturing an image forming apparatus of the present invention, an electron source is manufactured by the manufacturing method, and an image forming member for forming an image by an electron beam emitted from the electron source is manufactured. I do.

[0023]

When an energization forming is performed on the electron-emitting device which is a component of the electron source, first, the electroconductive film is subjected to an energization process to form an electron-emitting portion, and then the conductive film is reduced or agglomerated. Aggregation treatment is performed in the vicinity of the electron-emitting portion in an atmosphere containing a promoting gas. That is, the temperature of the conductive film rises due to the current (film current) flowing through the conductive film that is energized,
The film whose temperature has risen reacts with a gas that promotes reduction and aggregation, and the reduction further increases the current, causing aggregation in a portion of the conductive film and causing a local structural change to form an electron emission portion. Is done.

In the method of manufacturing an electron source according to the present invention, when heating the conductive film, an inert gas is introduced into the vacuum apparatus so as to have a predetermined pressure, and an energization forming is performed. While maintaining the pressure constant, a reducing or aggregating gas is introduced by a predetermined partial pressure. Here, since the thermal conductivity of the inert gas is close to that of the reducing or aggregating gas, there is almost no difference in the thermal conductivity between the substrate heating means and the substrate, and the temperature unevenness in the position on the substrate surface. Is suppressed. Therefore, even if the conductive films of a large number of electron-emitting devices formed on the substrate are provided at any positions on the surface of the substrate, forming can be performed on each of the devices in substantially the same manner.
As described above, according to the present invention, it is possible to realize uniform forming of the electron-emitting devices and form a uniform electron-emitting portion over all the electron-emitting devices. This is effective when energization forming is performed on the substrate.

By manufacturing an image forming apparatus using such an electron source, an image forming apparatus having uniform luminance characteristics is realized.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing an electron source and a method for manufacturing an image forming apparatus according to the present invention will be described. This will be described in detail with reference to the drawings.

As the electron-emitting device used in the image forming apparatus of the present embodiment, for example, the device disclosed in Japanese Patent Application Laid-Open No. 7-235255 can be used. The basic structure of the electron-emitting device is roughly classified into two types: a planar type and a vertical type. Hereinafter, only the basic configuration of the planar element will be outlined.

FIGS. 1A and 1B are schematic views showing the configuration of a planar surface conduction electron-emitting device used in the present embodiment. FIGS. 1A and 1B are a plan view and a cross-sectional view, respectively. In FIG. 1, 1 is a substrate, 2 and 3 are device electrodes, 4 is a conductive film, and 4 is 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, a glass substrate in which blue plate glass is laminated with SiO ₂ formed by sputtering or the like, ceramics such as alumina, and a Si substrate. Can be used.

The materials of the opposing device electrodes 2 and 3 are as follows.
General conductor materials can be used. The element electrode interval L, the element electrode length W, the shape of the conductive film 4, and the like are designed in consideration of the applied form and the like. Note that, in addition to the configuration shown in FIG. 1, a configuration in which a conductive film 4 and opposing element electrodes 2 and 3 are laminated on the substrate 1 in this order can be adopted.

As the conductive film 4, a fine particle film composed of fine particles is preferably used in order to obtain good electron emission characteristics. The film thickness is appropriately set in consideration of the step coverage for the device electrodes 2 and 3, the resistance value between the device electrodes 2 and 3, a forming condition described later, and the like.
It is preferably in the range of several times 0.1 nm to several hundred nm, and more preferably in the range of 1 nm to 50 nm. The resistance value is such that Rs is 10 ² to 10 ⁷ Ω / □. Note that Rs & is an amount that appears when the resistance R of a thin film having a thickness t, a width w, and a length l is R = Rs (l / w). In the present embodiment, 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 a process of forming a crack in the conductive film to form a high resistance state. Is what you do. The material constituting the conductive film 4 is Pd, Pt, Ag, Au, T
i, In, Cu, Cr, Fe, Zn, Sn, Ta, metals such as _{W, PdO, SnO 2, In 2} O 3, PbO, Sb
It is appropriately selected from oxides such as ₂ O ₃ . 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 in which the fine particles are individually dispersed or arranged or in a state in which the fine particles are adjacent to each other or overlapped (some fine particles are gathered, Including the case where an island-like structure is formed as a whole.) The particle size of the fine particles is
In the range from several times 0.1 nm to several hundred nm, preferably 1
nm to 20 nm.

The electron-emitting portion 5 is constituted by a high-resistance crack formed in a part of the conductive film 4 and depends on the thickness, film quality, material, and a method such as energization forming which will be described later. It will be. Inside the electron emission unit 5,
In some cases, conductive fine particles having a particle size ranging from several times 0.1 nm to several tens nm are present. The conductive fine particles contain some or all of the elements of the material constituting the conductive film 4. The electron emitting portion 5 and the conductive film 4 near the electron emitting portion 5 can also contain carbon and a carbon compound.

Hereinafter, an example of a method for manufacturing an electron-emitting device will be described with reference to FIGS. 2 to 5
, The same parts as those shown in FIG. 1 are denoted by the same reference numerals.

1) The substrate 1 is sufficiently washed with a detergent, pure water, an organic solvent, or the like, and after the element electrode material is deposited by a vacuum deposition method, a sputtering method, or the like, the substrate 1 is deposited on the substrate 1 using, for example, a photolithography technique. Then, device electrodes 2 and 3 are formed (FIG. 2A).

2) An organic metal solution is applied to the substrate 1 on which the device electrodes 2 and 3 are formed to form an organic metal thin film. As the organic metal solution, a solution of an organic metal compound containing the metal of the material of the conductive film 4 as a main element can be used. The organic metal thin film is heated and baked, and patterned by lift-off, etching, or the like to form a conductive film 4 (FIG. 2).
(B)). Here, the method of applying the organic metal solution has been described, but the method of forming the conductive film 4 is not limited to this, and the vacuum deposition method, the sputtering method, the chemical vapor deposition method, the dispersion coating method, A dipping method, a spinner method, or the like can also be used.

3) Subsequently, a forming step is performed to form an electron-emitting portion (FIG. 2C). Specifically, first, the substrate 1 on which the element electrodes 2 and 3 and the conductive film 4 are formed is set in a vacuum device.

Next, after the inside of the vacuum device is sufficiently evacuated by the exhaust device, an inert gas such as nitrogen is supplied. On this occasion,
The pressure in the vacuum device is adjusted to a desired value by the gas flow rate and the exhaust flow rate of the exhaust device of the vacuum pump.

Next, the substrate is heated to increase the temperature, and power is applied between the element electrodes 2 and 3 using a power supply (not shown).

Then, a gas for promoting the reduction and aggregation of the material of the conductive film 4 is introduced into the vacuum container, and the conductive film 4 is locally destroyed, deformed or deteriorated, and the structure is changed to a portion where the structure is changed. Is formed.

When introducing a gas that promotes reduction and coagulation, the flow rate of the inert gas is reduced or the exhaust flow rate of the vacuum pump is increased in order to minimize the pressure fluctuation in the vacuum apparatus due to the introduction. .

In this embodiment, as described above, the conductive film 4 is heated to a temperature equal to or higher than room temperature, and the electric conduction process is performed in an atmosphere containing a gas that promotes reduction or aggregation of the conductive film 4. Thus, at the same time as forming the electron-emitting portion 5,
Aggregation processing is performed in the vicinity of the electron emission portion. The temperature of the conductive film 4 rises due to the current (membrane current) flowing through the conductive film 4 that has been energized, and the temperature-raised film reacts with a gas that promotes reduction and aggregation, and further reduces the current to further increase the current. Then, a part of the conductive film 4 is aggregated to cause a local structural change to form an electron emission portion.

In the present embodiment, the temperature at which the substrate 1 on which the conductive film 4 is formed is heated and held is appropriately determined depending on the material of the conductive film 4. The agglomeration reaction becomes excessive and a preferable electron-emitting portion is not formed, or the agglomeration proceeds in the entire conductive film, and the agglomerated particles do not come into contact with each other, resulting in a loss of conduction as a whole. The upper limit of the holding temperature is preferably 100 ° C. or less, for example, when the material of the conductive film is PdO fine particles. Next, an example of the voltage waveform of the energization forming is shown in FIG.

The voltage waveform is preferably a pulse waveform. For this purpose, there is a method shown in FIG. 3 in which a pulse having a constant pulse height is applied continuously. T1 and T2 in FIG. 3 are the pulse width and pulse interval of the voltage waveform. Normal,
T1 is set in the range of 1 μsec to 10 msec, and T2 is set in the range of 10 μsec to 10 msec. The peak value of the triangular wave (peak voltage at the time of energization forming) is appropriately selected according to the electron emission element form.

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.

When the conductive film 4 is made of a metal oxide, a reducing gas such as H ₂ , CO, CH ₄ or the like can be used as the gas for promoting the reduction and aggregation of the material of the conductive film 4. . The reason is considered to be that aggregation occurs when the metal oxide is reduced into a metal. On the other hand, when the conductive film 4 was made of a metal, the aggregation promotion by CO or CH ₄ was not seen, but when H ₂ was used, the aggregation promoting effect was seen.

These gases include H ₂ , CO, CH
A mixed gas of ₄ and an inert gas may be used. In addition, as the inert gas, a gas which does not easily react with the members constituting the electron source substrate, such as a conductive film, can be selected. Specifically, for example, a rare gas such as nitrogen, argon, helium, or xenon is used.

4) The element after the forming is subjected to a process called an activation step. 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 repeating application of a pulse in an atmosphere containing an organic substance, similarly to the energization forming. 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 accordingly set as appropriate.

By this treatment, carbon or a carbon compound is deposited on the element from the organic substance existing in the atmosphere to the electron-emitting portion formed on the conductive film, and the element current If and the emission current Ie are significantly changed. I will be.

Here, the carbon and the carbon compound include, for example, graphite (so-called HOPG, PG, and GC. HOPG has an almost complete crystal structure of graphite;
G indicates that the crystal grain is about 200 ° and the crystal structure is slightly disordered, and GC indicates that the crystal grain is about 20 ° and the disorder of the crystal structure is further increased. ) And amorphous carbon (refer to amorphous carbon and a mixture of amorphous carbon and the microcrystals of graphite), and the thickness thereof is preferably in the range of 50 nm or less.
It is more preferable to set the range to 0 nm or less.

[0050] A suitable device that can be used in the present embodiment.
Alkanes, alkenes, and alkyne fats
Aromatic hydrocarbons, aromatic hydrocarbons, alcohols, alcohols
Dehydes, ketones, amines, phenol, carbo
And organic acids such as sulfonic acid.
Physically, C such as methane, ethane, and propane_nH_{2n + 2}so
Represented saturated hydrocarbon, ethylene, propylene, acetyl
C such as ren_nH_2n, C _nH_2nAnd C_nH_2n-2Composition formulas such as
Unsaturated hydrocarbon, benzene, methanol, d
Tanol, formaldehyde, acetaldehyde, ace
Ton, methyl ethyl ketone, methylamine, ethylami
Phenol, formic acid, acetic acid, propionic acid, etc.
Wear.

In the present embodiment, these organic substances may be used alone or, if necessary, may be used as a mixture. Further, these organic substances may be used after being diluted with another gas which is not an organic substance. Examples of the type of gas that can be used as the diluting gas include an inert gas such as nitrogen, argon, and xenon.

In the present embodiment, as a method of applying a voltage in the activation step, conditions such as a time change of a voltage value, a direction of the voltage application, a waveform, and the like can be considered. The time change of the voltage value can be performed by a method of increasing the voltage value with time or a method of performing the change with a fixed voltage.

As shown in FIG. 4, the voltage may be applied only in the same direction as the driving (forward direction) (FIG. 4 (a)), or alternately in the forward and reverse directions. (FIG. 4B). It is preferable to apply the voltage alternately because it is considered that the carbon film is formed symmetrically with respect to the crack. Although the example of a rectangular wave is used in FIG. 4 for the waveform, a sine wave, a triangular wave, a sawtooth wave
Any arbitrary waveform can be used.

The end of the activation step is determined as appropriate while measuring the device current If and the emission current Ie.

5) The electron-emitting device obtained through such a step is preferably subjected to a stabilization step. This step is a step of exhausting the organic substance in the vacuum vessel. It is preferable to use a device that does not use oil as a vacuum exhaust device that exhausts the vacuum container so that oil generated from the device does not affect the characteristics of the element. Specifically, a vacuum exhaust device such as a sorption pump and an ion pump can be used. The partial pressure of the organic component in the vacuum vessel is 1.3 × 1 at which the above-mentioned carbon and carbon compounds are not newly deposited.
It is preferably 0 ^-6 Pa or less, more preferably 1.3 × 10 ^-8 Pa or less.

Further, when the inside of the vacuum vessel is evacuated, it is preferable to heat the entire vacuum vessel so that the organic substance molecules adsorbed on the inner wall of the vacuum vessel and the electron-emitting device can be easily evacuated. The heating conditions at this time are desirably 80 to 250 ° C., preferably 150 ° C. or more, and it is desirable to perform the treatment for as long as possible. This is performed under conditions appropriately selected according to various conditions such as the above.

The pressure in the vacuum vessel needs to be as low as possible, preferably 1 × 10 ⁻⁵ Pa or less, and more preferably 3 × 10 ⁻⁵ Pa.
^-6 Pa or less is particularly preferable. 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, the pressure itself may be reduced. Can maintain a sufficiently stable characteristic even if the value slightly increases. By adopting such a vacuum atmosphere, the deposition of new carbon or a carbon compound can be suppressed, and H ₂ O, O _2, etc. adsorbed on a vacuum vessel or a substrate can be removed. The current Ie is stabilized.

The basic characteristics of the electron-emitting device to which the present invention obtained through the above-described steps can be applied will be described with reference to FIGS. FIG. 5 is a schematic view showing an example of a vacuum processing apparatus, and this vacuum processing apparatus also has a function as a measurement evaluation apparatus. In FIG. 5, the same parts as those shown in FIG. 1 are denoted by the same reference numerals as those shown in FIG. In FIG. 5, 55 is a vacuum vessel, and 56 is an exhaust pump. An electron-emitting device is provided in the vacuum vessel 55.

That is, reference numeral 51 denotes a device voltage Vf applied to the electron-emitting device.
Is a power supply for applying a voltage, 50 is an ammeter for measuring an element current If flowing through the conductive film 4 between the element electrodes 2 and 3,
Reference numeral 54 denotes an anode electrode for capturing an emission current Ie emitted from the electron emission portion of the device. Reference numeral 53 denotes a high-voltage power supply for applying a voltage to the anode electrode 54, and reference numeral 52 denotes an ammeter for measuring an emission current Ie emitted from the electron emission portion 5 of the device. As an example, the measurement can be performed with the voltage of the anode electrode in the range of 1 kV to 10 kV and the distance H between the anode electrode and the electron-emitting device in the range of 2 mm to 8 mm. In the vacuum vessel 55, devices necessary for measurement in a vacuum atmosphere such as a vacuum gauge (not shown) are provided so that measurement and evaluation can be performed in a desired vacuum atmosphere. The exhaust pump 56 is composed of a normal high vacuum device system including a turbo pump and a rotary pump, and an ultra high 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 by a heater (not shown). Therefore, by using this vacuum processing apparatus, the steps after the energization forming described above can also be performed.

FIG. 6 shows emission current Ie, device current If, and device voltage V measured using the vacuum processing apparatus shown in FIG.
FIG. 4 is a characteristic diagram schematically showing a relationship with f. In FIG. 6, since the emission current Ie is significantly smaller than the element current If, it is shown in arbitrary units. The vertical and horizontal axes are linear scales.

As is clear from FIG. 6, the electron-emitting device used in this embodiment has three characteristic properties with respect to the emission current Ie. That is, (i) the element is at a certain voltage (see FIG.
When an element voltage equal to or higher than Vth) is applied, the emission current Ie sharply increases, whereas when the element voltage is equal to or lower than the threshold voltage Vth, 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. (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 54 is:
It depends on the time for applying the element voltage Vf. That is, the amount of charge captured by the anode electrode 54 can be controlled by the time during which the device voltage Vf is applied.

As will be understood from the above description, the electron-emitting device used in the present invention can easily control the electron emission characteristics according to the input signal. Using this property, an electron source composed of a plurality of electron-emitting devices,
It can be applied to various fields such as an image forming apparatus. In FIG. 6, 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). These characteristics can be controlled by controlling the aforementioned steps.

The image forming apparatus of this embodiment can form an image by irradiating an electron source having a plurality of electron-emitting devices thus obtained arranged on a substrate and irradiating an electron beam from the electron source. It is configured in combination with an image forming member.

Regarding the arrangement of the electron-emitting devices, a plurality of electron-emitting devices are arranged in a matrix in the X and Y directions, and one of the electrodes of the plurality of electron-emitting devices arranged in the same row is connected to the wiring in the X direction. And the other of the electrodes of the plurality of electron-emitting devices arranged in the same column is commonly connected to the wiring in the Y direction. This is a so-called simple matrix arrangement.

First, the simple matrix arrangement will be described in detail below. In FIG. 7, 71 is an electron source substrate, and 72 is X
The direction wiring 73 is a Y-direction wiring. 74 is an electron-emitting device, and 75 is a connection. Note that the electron emitting element 74 may be of the above-mentioned flat type or vertical type.

The X-direction wiring includes m X-direction wirings 72, Dx
1, Dx2,…, Dxm. These can be made of a conductive metal or the like formed using a vacuum deposition method, a printing method, a sputtering method, or the like. The material, thickness and width of the wiring are appropriately designed. The Y-direction wiring 73 includes n wirings Dy1, Dy2,..., Dyn, and is formed in the same manner as the X-direction wiring 72. These m X-direction wires 72 and n Y-direction wires 7
3, an interlayer insulating layer (not shown) is provided.
Both are electrically separated (m and n are both positive integers).

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 71 on which the X-directional wiring 72 is formed. Materials and manufacturing methods are set as appropriate. The X-direction wiring 72 and the Y-direction wiring 73 are led out as external terminals. A pair of electrodes (not shown) constituting the electron-emitting device 74 are electrically connected to the m X-directional wires 72 and the n Y-directional wires 73 by a connection 75 made of a conductive metal or the like.

The material forming the X-direction wiring 72 and the Y-direction wiring 73, the material forming the connection 75, and the material forming the pair of element electrodes may have the same or some of the same constituent elements. Each may be different. These materials are appropriately selected, for example, from the above-described materials for the device electrodes. When the material forming the element electrode is the same as the wiring material, the wiring connected to the element electrode can also be called an element electrode.

As described above, the electron-emitting device obtained by the manufacturing method according to the present embodiment will be described with reference to (i) to (ii).
There is the characteristic of i). That is, when the electron emission from the electron-emitting device is equal to or higher than the threshold voltage, it can be controlled by the peak value and the width of the pulse voltage applied between the opposing device electrodes. On the other hand, when the voltage is equal to or lower than 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 element, an electron emission element can be selected and the amount of electron emission can be controlled according to an input signal.

For example, a scanning signal applying means (not shown) for applying a scanning signal for selecting a row of the electron-emitting devices 74 arranged in the Y direction is connected to the Y-direction wiring 73.
On the other hand, a modulation signal generating means (not shown) for modulating each column of the electron-emitting devices 74 arranged in the X direction according to an input signal is connected to the X-direction wiring 72. 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 a 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. FIG. 8 is a schematic view showing an example of a display panel of the image forming apparatus, and FIG. 9 is a schematic view of a fluorescent film used in the image forming apparatus of FIG. FIG.
FIG. 2 is a block diagram illustrating an example of a drive circuit for performing display according to an NTSC television signal.

8, reference numeral 71 denotes an electron source substrate on which a plurality of electron-emitting devices are arranged; 81, a rear plate on which the electron source substrate 71 is fixed; 86, a fluorescent film 84 on the inner surface of a glass substrate 83;
And a face plate on which a metal back 85 and the like are formed. Reference numeral 82 denotes a support frame to which a rear plate 81 and a face plate 86 are joined by using low melting point frit glass or the like. Reference numeral 74 corresponds to the electron-emitting portion in FIG. Reference numerals 72 and 73 denote an X-direction wiring and a Y-direction wiring connected to a pair of device electrodes of the electron-emitting device.

The envelope 88 includes the face-plate 86, the support frame 82, and the rear plate 81 as described above. Since the rear plate 81 is provided mainly for the purpose of reinforcing the strength of the substrate 71, if the substrate 71 itself has sufficient strength, the separate rear plate 81 can be unnecessary. That is, the support frame 82 is directly sealed to the substrate 71, and the envelope 8 is formed by the face plate 86, the support frame 82 and the substrate 71.
8 may be configured.

On the other hand, by providing a support (not shown) called a spacer between the face plate 86 and the rear plate 81, an envelope 88 having sufficient strength against atmospheric pressure may be formed. it can.

FIG. 9 is a schematic diagram showing a fluorescent film. The fluorescent film 84 can be composed of only a phosphor in the case of monochrome. In the case of a color fluorescent film, it can be composed of a black conductive material 91 called a black stripe or a black matrix and a fluorescent material 92 depending on the arrangement of the fluorescent materials. The purpose of providing the black stripes and the black matrix is to make the color separation between the phosphors 92 of the necessary three primary color phosphors black in the case of color display so that color mixing and the like become inconspicuous. An object of the present invention is to suppress a decrease in contrast due to light 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 phosphor on the glass substrate 93 can employ a precipitation method, a printing method, or the like irrespective of monochrome or color. Usually, a metal back 85 is provided on the inner surface side of the fluorescent film 84. The purpose of providing the metal back is to convert the light emitted from the phosphor toward the inner surface into the face plate 86.
Improving the brightness by specular reflection to the side,
The purpose is to function as an electrode for applying an electron beam acceleration voltage, and to protect the phosphor from damage due to collision of negative ions generated in the envelope. The metal back can be manufactured by performing a smoothing process (usually called “filming”) on the inner surface of the fluorescent film after manufacturing the fluorescent film, and then depositing Al using vacuum evaporation or the like.

The face plate 86 further has a fluorescent film 8
A transparent electrode (not shown) may be provided on the outer surface side of the fluorescent film 84 in order to increase the conductivity of the phosphor film 84. When performing the above-described sealing, in the case of color, it is necessary to make each color phosphor correspond to the electron-emitting device, and sufficient alignment is indispensable.

An example of a method for manufacturing the image forming apparatus shown in FIG. 8 will be described below. FIG. 19 is a schematic diagram showing an outline of an apparatus used in this step. A heating stage 17 for heating the electron source substrate 71 is provided in the vacuum chamber 181.
1, and the electron source substrate 71 is held on this heating stage. The surface temperature of the heating stage 171 can be maintained at a constant temperature by measuring the surface temperature by a temperature detecting means (not shown) such as a thermocouple and adjusting the power supplied to the heating stage based on the value. .

The X-direction wiring and the Y-direction wiring formed on the electron source substrate 71 are respectively m and n contact pins 174 and 175 (m in the illustrated example) at the end of the electron source substrate.
Only two out of xn lines are shown. The same applies hereinafter. ), Electrical connection is made from each contact pin, and conductive metal wires 189, 190 (only two of m × n wires are shown in the illustrated example; the same applies hereinafter) and current introduction terminals 187, 1 from each contact pin.
Via 88, it is taken out of the vacuum chamber.

The vacuum chamber 181 has a pressure gauge 173
In addition, a gas introduction line 182 for introducing an inert gas, a reducing gas, and a cohesive gas necessary for forming into a vacuum chamber is provided. The other end of the gas introduction line 182 is connected to each gas supply source (for example, a compressed gas cylinder or the like), and a mass flow controller or the like is provided in the gas introduction line in order to introduce a certain amount of gas into the vacuum chamber. Are provided.

An exhaust device 186 for exhausting the gas inside the vacuum chamber 181 is connected via a valve 185 whose conductance can be changed, and the exhaust gas flow rate is controlled by controlling the opening degree of the valve. Can be changed.

As described above, by controlling the flow rate of the gas introduction and the flow rate of the gas exhaust, the pressure in the vacuum chamber and the concentration of the reducing and aggregating gas contained in the gas in the vacuum chamber are controlled. Is possible.

In the forming, the electron source substrate 71 is held on a heating stage in a vacuum chamber 181, and an inert gas such as nitrogen is introduced into the vacuum chamber 181. At this time, the flow rate of the gas exhausted from the vacuum chamber 181 and the amount of the gas introduced into the vacuum chamber 181 are controlled so that the pressure in the vacuum chamber becomes substantially constant. In this state, the heating stage 171 is heated to heat the electron source substrate 71.

Next, the contact pins 174 and 175 in the vacuum chamber 181 are connected to the X-direction wiring on the electron source substrate and to the Y-direction.
The contact is made at the end of the directional wiring, and the electrical connection is taken out of the vacuum chamber via a conductive metal wire or the like. They are,
It is connected to a power supply (not shown) outside the vacuum chamber by a cable (not shown), and can apply a voltage from the power supply to the wiring on the electron source substrate 71 in the vacuum chamber 181.

Further, as shown in FIG.
The voltage can be applied to all of the elements in the electron source substrate by sequentially applying (scrolling) a pulse having a phase shifted to the Y-direction wiring 73 by using only the two in common. In the drawing, reference numeral 143 denotes a current measuring resistor, and 144 denotes a current measuring oscilloscope. At this time, conditions such as the shape of the pulse and the determination of the end of the processing may be selected according to the above-described method for forming the individual elements.

Finally, a reducing and coagulating gas is introduced into the vacuum chamber. During the introduction of the gas, the amount of the inert gas may be reduced or the flow rate of the exhaust gas from the vacuum chamber may be increased according to the amount of the reducing and coagulating gas introduced so that the pressure in the vacuum chamber does not fluctuate. it can.

Under these circumstances, in each conductive film formed on the electron source substrate, the temperature rises due to an applied current (film current), and the film whose temperature has risen promotes reduction and aggregation. By reacting with the gas and reducing it, the current further increases, and eventually a part of the conductive film 4 aggregates, causing a local structural change, forming an electron emission portion, and completing the forming. I do.

In the present embodiment, the energization forming is preferably performed in the following procedure. (1) The pressure in the vacuum chamber is kept constant by introducing an inert gas. (2) Heat the electron source substrate. (3) Apply a voltage to the device electrodes on the electron source substrate. (4) While keeping the pressure in the vacuum chamber constant,
A reducing or aggregating gas is introduced.

The following are the reasons why this procedure is preferable. In the heating of the electron source substrate in (2), the electron source substrate is heated by heat conduction from a heating stage or the like. Therefore, even if the electron source substrate is heated to a desired temperature by the heating stage, the inert gas is thereafter discharged. When introduced, the thermal conductivity between the electron source substrate and the heating stage changes, and the temperature of the electron source substrate changes. Therefore, it takes a long time until the temperature becomes stable again at the desired temperature. In particular, heating in an inert gas has better thermal conductivity than heating in a vacuum, so that the heating time is shorter. Therefore, it is preferable to perform (2) after (1).

The metal oxide constituting the conductive film is (4)
Is reduced to a metal film only by exposure to an atmosphere of a cohesive gas. In forming, a voltage is simultaneously applied to a large number of conductive films on an electron source substrate via a common wiring, so when the conductive film is a metal film having a small electric resistance, a current flowing through the wiring becomes extremely large. I will. Flowing a large current through the wiring may cause disconnection or the like due to evaporation of the wiring material. In addition, power supply equipment for flowing a large current is required, and the cost of the apparatus is increased. Therefore, in complete forming, it is necessary to apply a voltage in the process of reducing the conductive film to a metal film, and therefore it is preferable to perform (4) after (3).

The restrictions on the order of (1), (2), and (3) are not so clear, but from the viewpoint of avoiding unnecessary long-time voltage application to the element, (3) is added after (2). )
Is preferably performed.

In the present embodiment, when reducing and introducing a cohesive gas by energization forming, the pressure fluctuation in the chamber is small, so that there is little change in the heat conduction between the heating stage and the electron source substrate, Is easy to maintain even during the energization forming. Therefore, even for the electron-emitting devices formed at various positions in the substrate surface, uniform energization forming conditions can be maintained, so that the uniformity of the shape of the obtained electron-emitting portion can be improved. .

By using the electron source substrate thus obtained for an image forming apparatus, an image forming apparatus having excellent luminance uniformity can be obtained.

Further, since the forming is performed in the chamber, the conductance of the gas can be designed relatively freely as compared with the conventional case where the envelope is formed and then formed therein. Can be easily performed. Therefore, the gas atmosphere at the time of forming can be manufactured stably and quickly.

In this embodiment, since the partial pressure ratio of the reducing and aggregating gas changes at the time of forming, the change in the thermal conductivity at the time of forming is smaller as the thermal conductivity of the reducing and aggregating gas and the inert gas is closer. This is preferable because the temperature distribution of the electron source substrate is easily maintained. For example, when hydrogen (thermal conductivity: 0.17 Wm ^-2 K ^-2 ) is used as a reducing and coagulating gas, helium (thermal conductivity: 0.14 Wm ^-2 K) is used as a gas having a thermal conductivity close to this. ^-2 ) is preferably used.

Even when using a gas other than those described above, hydrogen (heat conductivity: 0.17
When Wm ^-2 K ^-2 ) is used, the partial pressure ratio of the reducing and coagulating gas during forming is 10% with respect to the inert gas.
The following is preferred. The difference in thermal conductivity is about one order of magnitude, the difference from the thermal conductivity in an atmosphere of 100% inert gas does not substantially occur, and the substrate temperature distribution during forming hardly changes.

The partial pressure of the reducing and aggregating gas varies depending on the type of the gas.
Torr or more is preferable. If it is 10 mTorr or more, the reduction rate of the conductive film becomes a desired value, and the time required for forming does not take much time. From this, it is preferable that the pressure at the time of forming be 1 Torr or more.

The electron source substrate on which the forming has been completed is fixed on a rear plate, and is joined together with a face plate, a support frame and the like using low-melting frit glass or the like to form the envelope 88 described above. The obtained envelope 8
8 is provided with an exhaust pipe 132, and the following steps can be performed by the vacuum exhaust device having the configuration shown in FIG.

In FIG. 13, the envelope 88 is connected to a vacuum chamber 133 via an exhaust pipe 132, and further connected to an exhaust device 135 via a gate valve. The vacuum chamber 133 is provided with a pressure gauge 136, a quadrupole mass analyzer 137, and the like for measuring the internal pressure and the partial pressure of each component in the atmosphere. Since it is difficult to directly measure the pressure inside the envelope 88 of the image display device 131, the processing conditions are controlled by measuring the pressure inside the vacuum chamber 133 and the like. In the vacuum chamber 133, further necessary gas is supplied to the vacuum chamber 1
A gas introduction line 138 is connected to introduce the gas into the inside 33 and control the atmosphere. This gas introduction line 138
The other end is connected to an introduction substance source 140, and the introduction substance is stored in an ampoule, a cylinder or the like. In the middle of the gas introduction line, there is provided an introduction control means 139 for controlling the rate at which the introduced substance is introduced.
As the introduction amount control means, specifically, a valve such as a slow leak valve capable of controlling the flow rate to be released, a mass flow controller, or the like can be used according to the type of the substance to be introduced. After the inside of the envelope 88 is evacuated by the apparatus shown in FIG. 13, an organic substance is introduced from the gas introduction line 138.

By applying a voltage to each electron-emitting device in the atmosphere containing the organic substance formed in this way, carbon or a carbon compound, or a mixture of both, is deposited on the electron-emitting portion, and the amount of electron emission is reduced. The drastic rise is similar to the case of the individual element.

After completion of the activation step, it is preferable to perform a stabilization step as in the case of forming an individual element. While the envelope 88 is heated and maintained at 80 to 250 ° C., the gas is exhausted through an exhaust pipe 132 by an exhaust device 135 that does not use oil, such as an ion pump and a sorption pump.
After the atmosphere is made sufficiently low in organic substances, the exhaust pipe is heated with a burner to dissolve and seal off. In order to maintain the pressure after the envelope 88 is sealed, a getter process may be performed. This is because the getter disposed at a predetermined position (not shown) in the envelope 88 is heated by heating using resistance heating, high-frequency heating, or the like immediately before or after the envelope 88 is sealed. This is a process for forming a deposited film. The getter is usually composed mainly of Ba or the like, and maintains the atmosphere in the envelope 88 by the adsorption action of the deposited film.

Next, an example of the configuration of a drive circuit for performing television display based on an NTSC television signal on a display panel configured using electron sources in a simple matrix arrangement will be described with reference to FIG. . In FIG. 10, 1
01 is an image display panel, 102 is a scanning circuit, 103
Is a control circuit, and 104 is a shift register. 105 is a line memory, 106 is a synchronization signal separation circuit, 107 is a modulation signal generator, and VX and Va are DC voltage sources. The display panel 101 includes terminals Dox1 to Doxm, terminals Doy1 to Doy1.
yn and a high-voltage terminal Hv to connect to an external electric circuit. Terminals Doy1 to Doyn are provided with scanning signals for sequentially driving electron sources provided in the display panel, that is, electron emission element groups arranged in a matrix of M rows and N columns, one row at a time (M elements). Is applied.

To the terminals Dx1 to Dxm, a modulation signal for controlling the output electron beam of each of the electron-emitting devices in one row selected by the scanning signal is applied. The high-voltage terminal Hv is supplied with a DC voltage of, for example, 10 kV from a DC voltage source Va, which is used to apply sufficient energy to an electron beam emitted from the electron-emitting device to excite the phosphor. Acceleration voltage.

The scanning circuit 102 will be described. The circuit includes n switching elements inside (in the figure, S1 to Sn are schematically shown). Each switching element selects either the output voltage of the DC voltage source VX or 0 V (ground level) and is electrically connected to the terminals Dy1 to Dyn of the display panel 101. Each of the switching elements S1 to Sn is a control circuit 1
The circuit operates based on the control signal Tscan output from the switching element 03 and can be configured by combining switching elements such as FETs.

In the case of this example, the DC voltage source VX determines that the drive voltage applied to the unscanned element is equal to or lower than the electron emission threshold voltage based on the characteristics of the electron emission element (electron emission threshold voltage). It is set to output such a constant voltage.

The control circuit 103 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. This control circuit 103
Based on the synchronizing signal Tsync sent from the synchronizing signal separation circuit 106, each control signal of Tscan, Tsft and Tmry is generated for each unit.

The synchronizing signal separating circuit 106 is a circuit for separating a synchronizing signal component and a luminance signal component from an NTSC television signal input from the outside. Can be configured. The synchronizing signal separated by the synchronizing signal separating circuit 106 includes a vertical synchronizing signal and a horizontal synchronizing signal.
This is shown as a Tsync signal. The luminance signal component of the image separated from the television signal is represented as a DATA signal for convenience. The
The DATA signal is input to the shift register 104.

The shift register 104 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 103. (That is, the control signal Tsft can be said to be a shift clock of the shift register 104). Cereal/
The data of one line of the parallel-converted image (corresponding to the drive data of the M electron-emitting devices) is output from the shift register 104 as M parallel signals of Id1 to Idm.

The line memory 105 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 Idm as appropriate according to a control signal Tmry sent from the control circuit 103. The stored contents are output as I'd1 to I'dm, and the modulated signal generator 10
7 is input.

The modulation signal generator 107 outputs the image data I'd1
To a signal source for appropriately driving and modulating each of the electron-emitting devices according to each of I′dm to I′dm, and the output signal is a terminal
The voltage is applied to the electron-emitting devices in the display panel 101 through Dox1 to Doxm. 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 V 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, but when a voltage higher than the electron emission threshold is applied, an electron beam is output. At this time, the pulse peak value V
By changing m, the intensity of the output electron beam can be controlled. In addition, it is possible to control the total amount of charges of the output electron beam by changing the pulse width Pw.

Therefore, as a method of modulating the electron-emitting device according to 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 107. be able to.

In implementing the pulse width modulation method,
As the modulation signal generator 107, 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 104 and the line memory 10
5 can be either 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 system is used, it is necessary to convert the output signal DATA of the synchronizing signal separation circuit 106 into a digital signal. For this purpose, an A / D converter may be provided at the output of the synchronization signal separation circuit 106. In connection with this, the line memory 105
The circuit used for the modulation signal generator 107 is slightly different 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 107, and an amplification circuit and the like are added as necessary. In the case of the pulse width modulation method, the modulation signal generator 107 includes, for example, a high-speed oscillator, a counter for counting the number of waves output from the oscillator, and a comparator for comparing the output value of the counter with the output value of the memory. (Comparator) is used. If necessary, an amplifier for amplifying the pulse width modulated signal output from the comparator to the drive voltage of the electron-emitting device can be added.

In the case of the voltage modulation method using an analog signal, an amplification circuit using, for example, an operational amplifier can be used as the modulation signal generator 107, and a level shift circuit and the like can be added as necessary. In the case of the pulse width modulation method, for example, a voltage-controlled oscillation circuit (VOC) can be employed, and an amplifier for amplifying the voltage up to the drive voltage of the electron-emitting device can be added as necessary.

In the image display device of the present invention which can take such a configuration, each of the electron-emitting devices is provided with an external terminal Dox1.
When a voltage is applied through Doxm and Doy1 to Doyn, electron emission occurs. A high voltage is applied to the metal back 85 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 84 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. For input signals, NTSC
Although the input signal is described above, the input signal is not limited to this. For example, a PAL or SECAM method or a TV signal including a larger number of scanning lines (for example, a high-definition TV signal such as the MUSE method) is used. Can also be adopted.

FIG. 11 is a schematic view showing an example of a ladder type electron source. In FIG. 11, reference numeral 110 denotes an electron source substrate, and 111 denotes an electron-emitting device. 112, Dx1 to Dx10
Is a common wiring for connecting the electron-emitting devices 111. A plurality of the electron-emitting devices 111 are arranged on the substrate 110 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 wires 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, and a voltage equal to or lower than the electron emission threshold is applied to an element row that does not emit an electron beam. Common wiring between each element row
For Dx2 to Dx9, for example, Dx2 and Dx3 can be made the same wiring.

FIG. 12 is a schematic diagram showing an example of a panel structure in an image forming apparatus provided with a ladder-type electron source. Reference numeral 120 denotes a grid electrode, 121 denotes a hole for passing electrons, and 122 denotes an external terminal made of Dox1, Dox2,. 123 is connected to the grid electrode 120
.. Gn, outside terminals of the container, and 124 is an electron source substrate in which the common wiring between the element rows is the same wiring. FIG.
In FIG. 2, the same portions as those shown in FIGS. 8 and 11 are denoted by the same reference numerals as those shown in these drawings.
The major difference between the image forming apparatus shown here and the image forming apparatus having the simple matrix arrangement shown in FIG. 8 is that the grid electrode 12 is disposed between the electron source substrate 110 and the face plate 86.
0 or not.

In FIG. 12, a grid electrode 120 is provided between the substrate 110 and the face plate 86. The grid electrode 120 modulates the electron beam emitted from the electron-emitting device, and allows the electron beam to pass through a stripe-shaped electrode provided orthogonal to the ladder-shaped element row. Therefore, one for each element
A circular opening 121 is provided for each piece. 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 emission element.

The outer container terminal 122 and the grid outer terminal 123 are electrically connected to a control circuit (not shown). In the image forming apparatus of the present embodiment, a modulation signal for one line of an image is simultaneously applied to the grid electrode columns in synchronization with sequentially driving (scanning) the element rows one by one. This allows
By controlling the irradiation of each electron beam to the phosphor, an image can be displayed line by line.

The image forming apparatus of the present embodiment can be used as a display device for a television broadcast, a display device such as a video conference system or a computer, or an image forming device as an optical printer using a photosensitive drum or the like. Can also be used.

[0124]

The present invention will be described in more detail with reference to the following examples. Embodiment 1 In this embodiment, an image forming apparatus used for display and the like will be described. FIG. 8 is a basic configuration diagram of the image forming apparatus, and FIG. 9 is a fluorescent film. FIG. 15 is a plan view of a part of the electron source. FIG. 16 is a sectional view taken along the line AA ′ in the figure. However, the same reference numerals in FIGS. 15 and 16 indicate the same components. Here, 71 is a substrate, 72 is an X-direction wiring (also referred to as a lower wiring) corresponding to Doxm in FIG.
Is a Y-direction wiring (also referred to as an upper wiring) corresponding to Doyn in FIG. 8, 4 is a thin film including an electron emitting portion, 2 and 3 are device electrodes,
151 is an interlayer insulating layer; 152 is an element electrode 2 and a lower wiring 72;
And a contact hole for electrical connection.

In the electron source of this embodiment, 3
00 and 100 electron-emitting devices are formed on the Y-direction wiring. Next, a method of manufacturing an electron source will be described with reference to FIGS.
The process will be specifically described with reference to FIG.

Step a 5 nm thick Cr and 600 nm thick Au were deposited by vacuum evaporation on a substrate 71 in which a 0.5 μm thick silicon oxide film was formed on a soda lime glass (2.8 mm thick) by sputtering.
Are sequentially laminated, a photoresist (manufactured by AZ1370 Hoechst) is spin-coated with a spinner, baked, and then a photomask image is exposed and developed to form a resist pattern of the lower wiring 72, and an Au / Cr deposited film is formed. The lower wiring 72 having a desired shape is formed by wet etching (FIG. 17A).

Step b Next, an interlayer insulating layer 151 made of a silicon oxide film having a thickness of 1.0 μm is deposited by RF sputtering (FIG. 17).
(B)).

Step c A contact hole 1 was formed in the silicon oxide film deposited in Step b.
A photoresist pattern is formed for forming the first and second interlayer insulating layers 151 using the photoresist pattern as a mask.
A contact hole 152 is formed (FIG. 17C).
Etching is performed using RIE (Rea) using CF ₄ and H ₂ gas.
active ion etching) method.

Step d Thereafter, a pattern to be a gap G between the device electrode 2 and the device electrode 3 is formed by a photoresist (RD-2000N-41).
Formed by Hitachi Chemical Co., Ltd., and 5 nm thick by vacuum evaporation
Of Ti and 100 nm of Ni were sequentially deposited. The photoresist pattern was dissolved with an organic solvent, and the Ni / Ti deposited film was lifted off. The element electrode interval L1 is 5 mm,
Assuming that the width W1 of the device electrode is 300 mm, the device electrodes 2, 3
Was formed (FIG. 17D).

Step e After forming a photoresist pattern of the upper wiring 73 on the element electrode 3, a 5 nm thick Ti and a 500 nm thick A
u was sequentially deposited by vacuum evaporation, and unnecessary portions were removed by lift-off to form upper wires 73 having a desired shape (FIG. 18A).

Step f A Cr film having a thickness of 100 nm is deposited and patterned by vacuum evaporation, and organic Pd (ccp4230 manufactured by Okuno Pharmaceutical Co., Ltd.) is spin-coated thereon by a spinner and heated and baked at 300 ° C. for 10 minutes. Did. The conductive film 4 composed of fine particles of PdO as the main element formed as described above has a thickness of 10 nm and a sheet resistance of 5 × 10 5.
It was ⁴ Ω / □ (FIG. 18 (B)).

Thereafter, the Cr film 153 and the baked conductive film 4 were etched with an acid etchant to form a desired pattern.

Step g A pattern is formed such that a resist is applied to portions other than the contact hole 152, and the thickness is 5 nm by vacuum evaporation.
Of Ti and Au with a thickness of 500 nm were sequentially deposited. Unnecessary portions were removed by lift-off to bury the contact holes 152 (FIG. 18C).

Through the above steps, the lower wiring 72, the interlayer insulating layer 151, the upper wiring 73, the device electrodes 2 and 3, the conductive film 4, and the like were formed on the insulating substrate 71.

Next, the produced electron source substrate was placed in a forming vacuum chamber having the structure shown in FIG.
Inside the vacuum chamber, there was a heating stage 171 with a built-in sheath heater, and the electron source substrate held on the heating stage was held. At both ends of the upper wiring on the electron source substrate, electrical connection is made by contact pins, which are taken out of the vacuum chamber through the cables and the current introduction terminals from the contact pins.

At the end of the lower wiring, an indium sheet is pressed on the wiring to be common. From the indium sheet, it is taken out of the vacuum chamber via a cable and a sealing component as in the case of the upper wiring.

After the inside of the chamber was evacuated to 1 × 10 ^-2 Pa, a nitrogen gas was flown into the chamber at a flow rate of 1 SLM, and simultaneously, the nitrogen gas was evacuated from the chamber to keep the pressure in the chamber at 1330 Pa. The introduction of nitrogen gas into the chamber was controlled by a mass flow controller, while the flow rate of exhaust gas from the chamber was controlled by an exhaust device and a conductance valve for controlling the flow rate.

Next, the temperature of the heating stage was raised, and the temperature of the electron source substrate was kept at 50 ° C. At this time, the temperature distribution in the substrate surface was ± 5 ° C. with respect to 50 ° C.

From a power supply installed outside the chamber,
A rectangular wave with a pulse width of 100 μs is converted to a scroll frequency of 60H.
The voltage was sequentially applied to the upper wiring at z. The voltage value was 10 V. The common lower wiring was grounded to ground.

A mixed gas of hydrogen and nitrogen (2% hydrogen, 98% nitrogen) was introduced into the chamber at 500 sccm, and at the same time, the flow rate of the already introduced nitrogen gas was 500 sccm.
cm.

[0142] When the current was passed through the conductive film for 10 minutes, the value of the current flowing through the conductive film became almost 0, the application of the voltage was stopped, and the forming was completed. It was created. During this time, the temperature distribution in the substrate surface was ± 8 ° C. at the time when the distribution occurred most.

In the electron-emitting portion 5 thus manufactured, fine particles mainly composed of palladium were dispersed and arranged, and the fine particles had an average particle diameter of 3 nm.

Next, an example in which a display device is constructed using the electron source substrate formed as described above is shown in FIG.
This will be described with reference to FIG.

On the electron source substrate 71, the conductive frit paste is applied on the upper wiring 73 corresponding to the connection portion 182 by using a dispenser, and firing is performed in a state where one end of the spacer 160 is disposed thereon. Then, a spacer was set up on the electron source substrate.

Next, after the other end of the spacer 160 is applied by using a dispenser, the face plate 85 is arranged in accordance with a black conductive material (black stripe). 42
The envelope 164 shown in the figure is baked at 0 ° C. for 10 minutes or more.
It was created. 20, reference numeral 74 denotes an electron-emitting device;
Reference numerals 2 and 73 denote wirings in the X and Y directions, respectively.

FIG. 21 is a schematic view of a cross section of the envelope in the X wiring direction. For fixing the spacer 160 to the upper wiring and the face plate 86, a conductive frit paste containing a filler of soda lime glass spheres whose surfaces were plated with Au was used.

At this time, the average particle size of the soda lime sphere was about 8 μm. The conductive layer on the surface of the filler was formed by using an electroless plating method by forming a Ni film of about 0.1 μm as a base and an Au film of about 0.04 μm thereon.
This conductive filler is added to the frit glass powder by 30
%, And a binder was added to prepare a conductive frit paste.

The spacer 160 is made of soda lime glass processed to have a width of 0.6 mm, a length of 75 mm, and a height of 4 mm by an etching method. A semiconductive film 162 made of a nickel oxide film is provided on the spacer 160. .

The nickel oxide film was formed by using a sputtering apparatus and sputtering in an argon / oxygen mixed atmosphere using nickel oxide as a target. Note that the substrate temperature during sputtering was 250 ° C.

The arrangement of the spacers is such that two spacers are arranged side by side on one upper wiring, and spacers are arranged every ten lines, so that
Are arranged so as to be divided into 10 in the upper wiring direction.

As the fluorescent film 93 on the face plate, color phosphors 95, 96, 97 having a black stripe arrangement and composed of a black conductive material 94 and a phosphor 92 were used. First, a black stripe was formed, and phosphors of each color were applied to the gaps, thereby forming a fluorescent film 93. A slurry method was used as a method of applying a phosphor on a glass substrate.

A metal back 85 was provided on the inner surface of the fluorescent film 93. After the fluorescent film is formed, the metal back 85
The phosphor film was manufactured by performing a smoothing process (usually called filming) on the inner surface of the phosphor film, and then vacuum-depositing Al. At the time of performing the above-mentioned sealing, in the case of color, it is necessary to make each color phosphor correspond to the electron-emitting device, so that sufficient alignment was performed.

The envelope 164 completed as described above was connected to a vacuum device evacuated by a magnetically levitated turbomolecular pump via an exhaust pipe (not shown).

Thereafter, the inside of the envelope 164 is 1.3 × 10 ^−4.
The vessel was evacuated to Pa and the envelope was heated at 200 ° C. for 2 hours and cooled to room temperature.

Next, the envelope 164 is passed through a vacuum device.
Benzonitrile in 6.6 × 10 ^-FourTo be Pa
Introduced.

The external terminals Dox1 to Doxm (m = 300) were made common, and Doy1 to Doyn (n = 100) were connected to a power supply (not shown) via a switching box (not shown).

Synchronize the switching box with the power supply,
From the lines Doy1 to Doyn (n = 100), 10 lines are selected at intervals of 10 lines, and a voltage is applied to these 10 lines in a time-division manner, and a voltage is applied between the electrodes 2 and 3 of the corresponding electron-emitting device 74. Was applied to perform an activation step.

The voltage application conditions in the activation step are as follows: peak value ± 10 V, pulse width 0.1 ms, pulse interval 50.1 m
A rectangular wave (FIG. 4 (b)) having both polarities of seconds was used. Thereafter, the peak value of the square wave was 3.3 mV / ± 10 V to ± 14 V.
The voltage was gradually increased in seconds, and when the voltage reached ± 14 V, the voltage application was terminated. This process was repeated 10 times to activate all the devices.

Thereafter, the benzonitrile in the envelope 164 was evacuated. Finally, as a stabilization step, about 1.33 × 1
After baking at 150 ° C. for 10 hours at a pressure of 0 ⁻⁴ Pa, the exhaust pipe (not shown) was welded by heating with a gas burner, and the envelope 164 was sealed.

In the image forming apparatus of the present invention completed as described above, each electron-emitting device has external terminals Dox1 to Doxm (m = 300) and Doy1 to Doyn (n = 10).
0), a scanning signal and a modulation signal are applied from signal generation means (not shown) to emit electrons, and a high voltage of 6 kV or more is applied to the metal back 9 through the high voltage terminal Hv to accelerate the electron beam. The image was displayed by colliding with the fluorescent film 84 to excite and emit light.

At this time, a pulse voltage was applied from each of the X-direction wiring and the Y-direction wiring, and the variation in the electron emission characteristics (If, Ie) of each electron-emitting device in the image forming apparatus was measured. % And Ie were 8%. Here, the variation is a value obtained by dividing the variance value by the average value of the If and Ie values of each element.

<< Comparative Example 1 >> In the forming of Example 1,
The electron source substrate was heated at a total pressure of 1 × 10 ⁻² Pa without introducing an inert gas.

Next, after the exhaust flow rate of the chamber was set in the same manner as in Example 1, 500 sccm of nitrogen gas and 500 sccm of a mixed gas of hydrogen and nitrogen were introduced into the chamber. The total pressure was 1330 Pa.

Thereafter, the same operation as in Example 1 was performed, and the electron emission characteristics (I) of each electron emission element in the obtained image forming apparatus were obtained.
f, Ie) were measured, the If was 15
% And Ie were 20%.

Example 2 Example 1 was repeated except that helium was used as the inert gas, and a mixed gas of hydrogen and helium (2% hydrogen, 98% helium) was used as the reducing and aggregating gas. When the variation of the electron emission characteristics (If, Ie) of each electron-emitting device in the obtained image forming apparatus was measured, it was 6% for If and 7% for Ie.

[0166]

According to the present invention, when a large number of electron-emitting devices are formed on a large-area substrate, when the conductive film of each of the electron-emitting devices is subjected to energization forming, almost all of the electron-emitting devices are formed. Form a uniform electron emission part,
Each electron-emitting device can realize an electron source having uniform electron emission characteristics.

Further, by using an image forming apparatus having this electron source and an image forming member for forming an image with an electron beam emitted from the electron source, an image forming apparatus having uniform luminance characteristics can be obtained.

In this embodiment and this embodiment, the image display device having a simple matrix arrangement is shown. However, any device may be used as long as electrons from the electron-emitting devices collide with the phosphor. In addition, the electron-emitting device obtained by the manufacturing method of the present invention can be applied to an electron beam (EB) drawing apparatus and a recording apparatus. According to the manufacturing method of the present invention, these devices can be manufactured by simple steps.

[Brief description of the drawings]

FIG. 1 is a schematic plan view and a cross-sectional view illustrating a configuration of a basic electron-emitting device according to the present invention.

FIG. 2 is a process chart showing a method for manufacturing a device electrode of an electron-emitting device according to the present invention.

FIG. 3 is a characteristic diagram illustrating an example of a voltage waveform of energization forming according to the present invention.

FIG. 4 is a characteristic diagram showing an example of a voltage waveform in an activation step according to the present invention.

FIG. 5 is a schematic diagram illustrating an example of a vacuum processing apparatus having a measurement evaluation function.

FIG. 6 is a characteristic diagram showing an example of the relationship between the emission current Ie, the device current If, and the device voltage Vf for the electron-emitting device according to the present invention.

FIG. 7 is a schematic diagram showing an example of an electron source arranged in a simple matrix according to the present invention.

FIG. 8 is a schematic diagram illustrating an example of a display panel of the image forming apparatus of the present invention.

FIG. 9 is a schematic diagram illustrating an example of a fluorescent film.

FIG. 10 is a block diagram illustrating an example of a driving circuit for performing display in the image forming apparatus in accordance with an NTSC television signal.

FIG. 11 is a schematic view showing an example of an electron source having a ladder arrangement according to the present invention.

FIG. 12 is a schematic diagram illustrating an example of a display panel of the image forming apparatus of the present invention.

FIG. 13 is a schematic view of a vacuum evacuation apparatus for performing an activation step.

FIG. 14 is a schematic view showing a connection method for an energization forming step and an activation step.

FIG. 15 is a plan view of the electron sources of Examples 1 and 2 and Comparative Example 1.

FIG. 16 is a cross-sectional view of the electron sources of Examples 1 and 2 and Comparative Example 1.

FIG. 17 is a process chart of the electron sources of Examples 1 and 2 and Comparative Example 1.

FIG. 18 is a process drawing of the electron source of Examples 1 and 2 and Comparative Example 1, following FIG. 17;

FIG. 19 is a schematic diagram of a vacuum exhaust device for performing an energization forming step.

FIG. 20 is a sectional view of an envelope of the image forming apparatus according to the present invention.

FIG. 21 is a schematic diagram illustrating an example of a display panel of the image forming apparatus of the present invention.

[Explanation of symbols]

1: substrate 2, 3: element electrode 4: conductive film 5: electron emitting portion 21: step forming portion 50, 55: ammeter 5
1, 53: Power supply 54: Anode electrode 56: Vacuum device 57: Exhaust pump 71: Electron source substrate 72: X direction wiring 73: Y direction wiring 74: Electron emitting element 75:
Connection 81: Rear plate 82: Support frame 83: Glass substrate 84: Fluorescent film 85: Metal back 86: Face plate 87: High voltage terminal 88: Envelope 91:
Black conductive material 92: Phosphor 93: Glass substrate 95:
Phosphor (R) 96: Phosphor (G) 97: Phosphor (B) 101: Display panel 102: Scanning circuit 10
3: Control circuit, 104: Shift register 105: Line memory 106: Synchronous signal separation circuit 107: Modulation signal generator Vx, Va: DC voltage source 131: Image display device 132: Exhaust pipe 133: Vacuum chamber 1
34: Gate valve 135: Exhaust device 136: Pressure 137: Quadrupole mass spectrometer 138: Gas introduction line 139: Introduced amount control means 140: Introduced material source 14
1: common electrode 142: power supply 143: current measuring resistor 151: interlayer insulating film 152: contact hole 1
60: spacer 161: semiconductive film 162, 16
3: connection part 164: envelope 171: heating stage
172: Q-Mass 173: Pressure gauge 174, 17
5: Contact pin 181: Vacuum chamber 18
2: Gas introduction line 183, 184: Gas introduction control device 185: Conductance adjustment valve 186: Exhaust device 187, 188: Current introduction terminal 189, 190:
Conductive metal wire

Claims (5)

[Claims] When manufacturing an electron source in which a plurality of electron-emitting devices having a conductive film between a pair of electrodes are formed on a substrate, a forming process for forming an electron-emitting portion in the conductive film is performed. In the method of manufacturing an electron source, a step of introducing an inert gas to a predetermined pressure in a vacuum device, a step of heating the substrate in the vacuum device, and a step of applying a voltage between the electrodes to form the substrate A method of manufacturing an electron source, comprising: performing a process; and mixing a reducing or aggregating gas with the inert gas while maintaining a constant pressure in the vacuum device. 2. The method according to claim 1, wherein the reducing gas is hydrogen. 3. The method according to claim 1, wherein the inert gas is helium or nitrogen. 4. The method for manufacturing an electron source according to claim 1, wherein the pressure in the vacuum device is 1 Torr or more. 5. An image forming member which forms an image by an electron beam emitted from the electron source while producing an electron source by the production method according to claim 1. A method for manufacturing an image forming apparatus, comprising: a forming apparatus.