JP2000251635A - Electron emission element and its manufacture, electron source, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of an electron emission element, in particular, a surface conduction type electron emission element, capable of realizing high luminance by means of a good electron emission characteristic and the increase in electron emission current and to provide an electron source and image formation device using it. SOLUTION: This electron emission element comprises a pair of opposed element electrodes 2, 3 formed on an insulating substrate 1, and a conductive thin film 4 having an electron emission part 5 formed between are pair of the element electrodes 2, 3. In this case, a layer formed between the insulating substrate 1 and the electron emission part 5 contains a metal oxide, and at least a part of the metal oxide is formed of a material which at least partially contains a material capable of being easily reduced by a reductive material, such as carbon. When the metal oxide is a single constituent oxide, the absolute value of standard production free energy per mol of the single constituent oxide is smaller than that of silica(SiO2) at the same temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold-cathode type electron-emitting device, a method for manufacturing the same, an electron source using the electron-emitting device, and an image forming apparatus using the electron source.

[0002]

2. Description of the Related Art Conventionally, electron-emitting devices are roughly classified into two types: a hot cathode electron-emitting device and a cold cathode electron-emitting device.
Kinds are 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”), and a surface conduction type electron-emitting device. WPDyke is an example of FE type
& WWDolan, “Field emission”, Advance in Electron
Physics, 8, 89 (1956) or CASpindt, “" Physical P
roperties of thin-film field emission cathodes wit
hmollybdenium cones ", J. Appl. Phys., 47, 5248 (1976).

As an example of the MIM type, CAMead, “Operati
on of Tunnel-Emission Devices ", J. Apply.Phys., 32, 64
6 (1961) and the like are known.

As an example of a surface conduction electron-emitting device, see MIElinson, Radio Eng. Electron Phys., 10, 129.
0, (1965) and the like.

[0005] The surface conduction electron-emitting device utilizes a phenomenon in which an electron is emitted when a current flows in a small-area thin film formed on a substrate in parallel with the film surface. Examples of the surface conduction electron-emitting device include a device using an SnO ₂ thin film by Elinson et al. And a device using an Au thin film.
[G. Ditmmer, Thin Solid Films, 9,317 (1972)], In ₂ O
₃ / SnO ₂ thin film [M. Hartwell and CGFons
ted, IEEE Trans. ED Conf., 519 (1975)], using a carbon thin film [Hisashi Araki et al .: Vacuum, Vol. 26, No. 1, 22]
1983).

As a typical example of these surface conduction electron-emitting devices, the above-mentioned M.S. Figure 1 shows the device configuration of Hartwell
FIG. In FIG. 1, reference numeral 1 denotes an insulating substrate. Reference numeral 4 denotes a conductive thin film, which has an H-shaped pattern,
The electron-emitting portion 5 is formed by a metal oxide thin film or the like formed by sputtering, and an energization process called energization forming described later. Note that the element electrode interval L in the figure is 0.
5-1 mm and W are set to 0.1 mm.

Conventionally, in these surface-conduction electron-emitting devices, the electron-emitting portion 5 is subjected to an energization process called energization forming before the electron emission.
It was common to form That is, the energization forming is to apply a DC voltage or a very slowly increasing voltage, for example, about 1 V / min, to both ends of the conductive thin film 4 and to energize the conductive thin film 4 to locally destroy, deform or alter the conductive thin film 4, The purpose is to form the electron-emitting portion 5 in a state of high resistance. In the electron emitting portion 5, a crack is generated in a part of the conductive thin film 4, and electrons are emitted from the vicinity of the crack. The surface conduction type electron-emitting device that has been subjected to the energization forming treatment causes the electron-emitting portion 5 to emit electrons by applying a voltage to the conductive thin film 4 and flowing a current to the electron-emitting device.

[0008]

With respect to the electron-emitting device, more stable electron emission characteristics and improved electron emission efficiency are provided so that an image forming apparatus using the electron-emitting device can stably provide a bright display image. Requested. The efficiency here is determined by the current flowing between the two electrodes when a voltage is applied to a pair of device electrodes of the surface conduction electron-emitting device (hereinafter, referred to as the current).
It is called “element current”. ) And the current emitted in a vacuum (hereinafter referred to as “electron emission current”). In order to improve the efficiency, electron emission with a small device current and a large emission current is considered. Devices are desired.

Here, if the electron emission characteristics that can be controlled stably and the efficiency are improved, for example, in an image forming apparatus using an image forming member formed with a phosphor, a high current image with low current and high quality can be formed. A device such as a flat television can be realized. Further, as the current is reduced, the cost of the driving circuit and the like constituting the image forming apparatus can be reduced.

However, the above-mentioned M.P. In the Hartwell electron-emitting device, satisfactory electron-emitting characteristics and electron-emitting efficiencies have not always been obtained. The fact is that it is extremely difficult to provide

Therefore, the electron-emitting device used for the above-mentioned application, particularly, the surface-conduction electron-emitting device has good electron-emitting characteristics with respect to a practically applied voltage, and exhibits such characteristics over a long period of time. It needs to be kept.

As a result of detailed studies, the present applicants have found that the maximum value of the device current of an electron-emitting device, especially a surface conduction electron-emitting device, is determined by the contact between the region where the electron-emitting portion is formed and the insulating substrate. The glass material (substrate material), which varies depending on the material of the region to be formed and contains a large proportion of an oxide material having a large free energy of formation per mole of oxide, such as alumina (Al ₂ O ₃ ), is used for the electron emission portion. In the case of the underlayer, the maximum value of the device current of the surface conduction electron-emitting device is low,
As a result, it was found that the luminance was reduced due to the small amount of electron emission.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides an electron-emitting device that achieves good electron emission characteristics and high brightness by increasing an electron emission current, particularly, a structure of a surface conduction electron-emitting device, and an electron source using the same. An image forming apparatus is provided.

[0014]

Means for Solving the Problems The present invention has been made by intensive studies in order to solve the above-mentioned problems, and has the following configuration.

That is, the electron-emitting device of the present invention comprises a pair of opposing device electrodes formed on an insulating substrate, and a conductive thin film having an electron-emitting portion formed between the pair of device electrodes. An electron-emitting device, wherein a layer formed between the insulating substrate and the electron-emitting portion contains a metal oxide, and at least a part of the metal oxide is easily reduced by a reducing material such as carbon. And a material containing at least a part of the material.

In the above-described electron-emitting device, when the metal oxide is a single-component oxide, silica (SiO) having a standard free energy of formation per mole of the single-component oxide of the same temperature is used. It is characterized in that its absolute value is smaller than the value of the standard free energy of formation per mole of ₂ ).

In the electron-emitting device, when the metal oxide is a composite oxide (base material + metal oxide), the value of the standard free energy of formation per mole of the composite oxide is the same. At temperature, one of the base materials
It is characterized in that its absolute value is smaller than the value of the standard free energy of formation per mole.

In the above-described electron-emitting device, the metal oxide may be an alkali metal (group 1A), an alkaline earth metal (group 2A), a group 6A, a group 7A, a group 8, a group 1B, a group 2B and a group consisting of Sn, It is characterized in that it is a single-component oxide of Pb, Sb, Bi, P or a composite oxide in which at least a part of the metal oxide is contained in a base material such as silica.

In the above-mentioned electron-emitting device, the material of the metal oxide is Cs ₂ O, K ₂ O, Na ₂ O, Cu
₂ O, BaO, CaO, MgO, SrO, PbO, Ni
O, SnO, CoO, Cr ₂ O ₃ , In ₂ O ₃ , Fe ₂
It is a single oxide of O ₃ , WO ₂ , or MnO ₂ or a composite oxide with silica (SiO ₂ ).

In the above-mentioned electron-emitting device, the base material is silica (SiO ₂ ), alumina (Al
₂ O ₃ ) and magnesia (MgO).

Further, in the above-mentioned electron-emitting device, the electron-emitting device is a surface conduction electron-emitting device.

According to another aspect of the present invention, there is provided an electron source for emitting electrons in response to an input signal, wherein a plurality of the above-mentioned electron-emitting devices are arranged on the insulating substrate.

In the above-mentioned electron source, a plurality of electron-emitting devices are arranged in parallel on the insulating substrate, and a plurality of rows of the electron-emitting devices having both ends of each of the electron-emitting devices connected to wiring are provided. And a modulating means for modulating the input signal.

In the above-mentioned electron source, a pair of element electrodes of the electron-emitting device are provided on m electrically isolated X-directional wirings and n electrically connected Y-directional wirings disposed on the insulating substrate. Wherein a plurality of the electron-emitting devices connected to are connected.

An image forming apparatus for forming an image based on an input signal, comprising at least an image forming member provided with a fluorescent film facing the insulating substrate, and the electron source. Features.

According to the present invention, there is provided an electron-emitting device comprising: a pair of opposing element electrodes formed on an insulating substrate; and a conductive thin film having an electron-emitting portion formed between the pair of element electrodes. In a manufacturing method, a layer containing a metal oxide is formed between the insulating substrate and the electron-emitting portion, and a material contained in at least a part of the metal oxide is reduced by a reducing material such as carbon. It is characterized by that.

In the above method for manufacturing an electron-emitting device, when the metal oxide is a single-component oxide, the value of the standard free energy of formation per mole of the single-component oxide is the same as that of the same temperature. When the absolute value is smaller than the value of the standard free energy of formation per mole of silica (SiO ₂ ), or when the metal oxide is a composite oxide (base material + metal oxide), the composite oxide The value of the standard free energy of formation per mole of the product is
It is characterized in that its absolute value is smaller than the value of the standard free energy of formation per mole of the base material.

According to the surface conduction electron-emitting device of the present invention, an electron-emitting device capable of maintaining stable electron emission characteristics for a long time can be realized.

Further, according to the image forming apparatus of the present invention, it is possible to form a stable and good image for a long time.

Hereinafter, the present invention will be described.

According to the study by the present applicant using various oxides for the underlying substrate, the underlying substrate for increasing the device current If and the electron emission current Ie is Cs ₂ O, K ₂ O, Na
₂ O, Cu ₂ O, BaO, CaO, MgO, SrO, P
bO, NiO, SnO, CoO, Cr 2 O 3, In 2 O
₃ , a single oxide of Fe ₂ O ₃ , WO ₂ , MnO ₂ or a composite oxide with silica (SiO ₂ ).

As shown in the following formula, it was found that these materials are materials whose reduction easily proceeds by metal oxide (M _x O _y ) carbon (C).

M _x O _y + yC ≧ xM + yCO Further examination by the Applicant shows that when these materials are compared at a certain temperature, the change in standard free energy of formation of the reaction in the above reaction is silica (Si)
It was found that a device having a smaller change in the standard free energy of formation of the reaction of O ₂ ) and a smaller absolute value of the change had a higher device current. This indicates that the process of obtaining the device current (called activation) involves the ease of reduction of the oxide.

In particular, it has been confirmed that the activation step to be described later is the deposition of carbon or a carbon compound. At this time, the reduction reaction between the oxide of the substrate and carbon as shown in the above reaction formula simultaneously proceeds. It is thought that it is. It is expected that the device current can be increased by using an oxide material in which the form of carbon or the carbon compound formed by the deposition and reduction reaction of carbon or the carbon compound is easily reduced.

These materials may be used as oxides having a single composition. However, in some cases, use of a composite oxide with silica (SiO ₂ ) is more excellent in luminance, life, and stability. .

[0036]

Next, preferred embodiments of the present invention will be described.

The basic structure of the surface conduction electron-emitting device to which the present invention can be applied is roughly classified into two types: a plane type and a vertical type.

(Flat-type surface conduction electron-emitting device)
The flat surface conduction electron-emitting device will be described.

FIG. 1 is a schematic diagram showing the configuration of a flat surface conduction electron-emitting device to which the present invention can be applied.
1A is a plan view, and FIG. 1B is a cross-sectional view.

In FIG. 1, 1 is an insulating substrate, 2 and 3 are device electrodes, 4 is a conductive thin film, 5 is an electron-emitting portion, and 6 is an oxide film.

As the insulating substrate 1, quartz glass, Na
Glass, blue plate glass with reduced impurity content, etc., a glass substrate obtained by laminating SiO ₂ on a blue plate glass by sputtering or the like, ceramics such as alumina, and a Si substrate can be used.

The material of the opposing device electrodes 2 and 3 is as follows.
General conductor materials can be used. This is, for example, Ni, Cr, Au, Mo, W, Pt, Ti, Al, C
metals or alloys such as u, Pd, and Pd, Ag, Au, R
It is appropriately selected from a printed conductor composed of a metal such as uO ₂ or Pd-Ag and a metal oxide and glass, a transparent conductor such as In ₂ O ₃ —SnO ₂ , and a semiconductor conductor material such as polysilicon. be able to.

The element electrode interval L, the element electrode length W, the shape of the conductive thin film 4 and the like are designed in consideration of the applied form and the like. The device electrode interval L can be preferably in the range of several thousand angstroms to several hundred micrometers, and more preferably, several micrometers to several tens of micrometers in consideration of the voltage applied between the device electrodes. In the range.

The length W of the device electrode can be set in a range from several micrometers to several hundred macrometers in consideration of the resistance value and the electron emission characteristics of the electrode. The film thickness d of the device electrodes 2 and 3 can be in the range of several hundred angstroms to several micrometers.

The oxide film 6, the opposing device electrodes 2, 3 and the conductive thin film 4 are formed on the insulating substrate 1 in the order shown in FIG. The conductive thin film 4, the oxide electrodes 6, the opposing device electrodes 2, 3, and the oxide film 6 are arranged in this order.
A configuration in which the opposing element electrodes 2 and 3 are laminated in this order may be employed.

As the conductive thin 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 step coverage for the device electrodes 2 and 3, a resistance value between the device electrodes 2 and 3, a forming condition described later, and the like. Generally, the thermal stability of the conductive thin film 4 is an important parameter that governs the lifetime of the electron emission characteristics, and it is desirable to use a material having a higher melting point as the material of the conductive thin film 4. However, in general, the higher the melting point of the conductive thin film 4 is, the more difficult it is to carry out energization forming, which will be described later. Further, the resulting electron-emitting portion may have a problem that the applied voltage (threshold voltage) at which electrons can be emitted increases.

In the present invention, the material of the conductive thin film 4 is not particularly required to be a material having a high melting point, and a material and a form capable of forming a good electron emitting portion with a relatively low forming power are selected. Can be.

Examples of materials satisfying the above conditions include Ni,
Preferably, a conductive material such as Au, PdO, Pd, or Pt is formed to have a film thickness having an Rs (sheet resistance) of 10 ² to 10 ⁷ Ω / □. Note that sheet resistance R
s is a resistance R of a thin film having a thickness t, a width w, and a length 1;
R = (Rs (l / w)). The film thickness exhibiting the above-mentioned resistance value is in the range of about 5 nm to 50 nm, and in this thickness range, the thin film of each material has the form of a fine particle film. 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 structure is formed as a whole). The particle size of the fine particles is 0. In the range of several nm to several hundred nm, preferably 1n
m to 20 nm.

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

Small particles are sometimes referred to as "fine particles", and smaller ones are sometimes referred to as "ultra fine particles". It is widely practiced to call a “cluster” smaller than “ultrafine particles” and having a few hundred atoms or less.

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.

For example, "Experimental Physics Course 14, Surfaces and Particles" (edited by Yoshio Kinoshita, published by Kyoritsu Shuppan, September 1, 1986) describes as follows.

In the present description, "fine particles have a diameter of about 2 to 3 μm to about 10 nm, and especially ultrafine particles have a particle diameter of about 10 nm to 2 to 3 nm.
It means up to about 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 22-26)
The definition of "ultra-fine particles" in the New Technology Development Corporation's "Hayashi and Ultra-fine Particle Project" was as follows, with the lower limit of the particle size being smaller.

In the “Ultra Fine Particle Project” of the Creative Science and Technology Promotion System (1981 to 1986), particles having a particle size (diameter) in the range of about 1 to 100 nm are referred to as “ultra fine particles”. I decided to call. Then, one ultrafine particle is an aggregate of about 100 to 108 atoms. 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, Mita Publishing)
(1988, page 2, lines 1 to 4) "A particle smaller than an ultrafine particle, that is, a single particle composed of several to several hundred atoms is usually called a cluster." (Id., Page 2, lines 12 to 13) Eye) Based on the general term as described above, "fine particles" in this specification are an aggregate of a large number of atoms and molecules, and the lower limit of the particle diameter is 0.1. Several nm to 1 nm
The upper limit and the upper limit refer to those of about several μm.

Among the materials of the conductive thin film 4 exemplified above, PdO can be easily formed into a thin film by sintering an organic Pd compound in the air, and since it is a semiconductor, PdO has relatively low electric conductivity. Range sheet resistance R
that the process margin of the film thickness for obtaining s is large, and that the metal Pd can be easily reduced after forming the electron-emitting portion, so that the film resistance is reduced and the heat resistance is increased.
It is a suitable material from the above. However, the effects of the present invention are not limited to PdO, and are not limited to the materials exemplified above.

Next, the electron-emitting portion 5 is constituted by a high-resistance crack formed in a part of the conductive thin film 4, and the film thickness, film quality, material and method of energization forming and the like to be described later. And so on. The inside of the electron emitting section 5 has a diameter of 0.1 mm. In some cases, conductive fine particles having a particle size ranging from several nm to several tens nm are present. The conductive fine particles contain some or all of the elements of the material constituting the conductive thin film 4. The electron emitting portion 5 and the conductive thin film 4 in the vicinity thereof contain carbon and a carbon compound after an activation step described later. It is known that the role of carbon and the carbon compound functions as a part of the conductive thin film 4 and governs the electron emission characteristics as a material constituting the electron emission portion 5, but details are not clear. .

As described above, the oxide film 6 is not limited to the oxide of a single metal element, but may be a composite oxide containing a plurality of metal elements.

For example, K ₂ O, Na ₂ O and Cs ₂ O are
Since the value of the standard free energy of formation is smaller than the absolute value of the free energy of formation of silica in the range of an absolute temperature of 700 K to 2000 K, the value of the standard free energy of formation is larger than that of the oxide used as a material for forming the electron-emitting portion. It can be easily reduced with materials such as C, Si, Al, Ti, Zr. In particular, C (carbon) does not form a solid oxide at the reaction interface because the oxidation product accompanying the reaction is CO gas. As a result, not only can the interfacial reaction be sustained, but also because carbon hardly dissolves metals and oxides, reduction products are immediately deposited on the surface, making it extremely ideal as a material for forming an electron-emitting portion. Special note as material.

The above K used for the oxide film 6
Many materials, such as ₂ O, Na ₂ O, and Cs ₂ O, whose standard free energy of formation is smaller than the absolute value of the free energy of formation of silica, often react with atmospheric moisture and have deliquescence. In many cases, it is difficult to use a single composition. Therefore, when these materials are used, it is more preferable to use them in a configuration of a mixed oxide film (base material + metal oxide). As a desirable base material at this time, silica (Si
O ₂ ), alumina (Al ₂ O ₃ ), magnesia (Mg
O) and the like.

On the other hand, for example, TiO, ZrO, Al ₂ O ₃
Materials with extremely large standard free energy of formation such as
When used as an oxide having a single composition, the above-mentioned C, Si,
It cannot be easily reduced with Al or the like. For example, Al ₂ O ₃
In order to reduce with carbon C, an absolute temperature of about 2000K is required, and it is not practical to raise the temperature of the reaction interface to this temperature.

For the purpose of improving the device current of the electron source, which is the object of the present invention, alkali metals (group 1A) and alkaline earth metals (2
A group), 6A group, 7A group, 8 group, 1B group, 2B group and S
A single composition oxide of n, Pb, Sb, Bi, and P or the above-mentioned oxide is desirable.

These oxides are generally formed on the substrate 1 by using a vacuum deposition method such as sputtering, but a simpler method is to use an alkoxide compound or a spin coat material. There is a method of producing an oxide by firing.

(Vertical type surface conduction electron-emitting device)
The vertical surface conduction electron-emitting device will be described.

FIG. 2 is a schematic view 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. 2, the same portions as those shown in FIG. 1 are denoted by the same reference numerals as those shown in FIG. 1, and duplicate description will be omitted. In the figure, reference numeral 21 denotes a step forming portion of an insulating material. Further, the substrate 1, the device electrodes 2 and 3, the conductive thin film 4, the electron-emitting portion 5, and the oxide film 6 can be made of the same material as in the case of the above-mentioned flat surface conduction electron-emitting device. The step forming section 21 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 21 corresponds to the device electrode interval L of the above-mentioned flat surface conduction electron-emitting device, and can be in the range of several hundred nm to several tens μm. The film thickness of the step forming portion 21 is set in consideration of the manufacturing method of the step forming portion 21 and the voltage applied between the element electrodes, and is preferably in the range of several tens nm to several μm.

Further, the conductive thin film 4 comprises the device electrodes 2 and 3
After the formation of the step forming portion 21, it is laminated on the device electrodes 2 and 3. Although the electron emitting portion 5 is formed in the step forming portion 21 in FIG. 2, the shape and the position are not limited to this depending on the forming conditions, forming conditions and the like.

There are various methods for manufacturing the above-mentioned surface conduction electron-emitting device. One example is schematically shown in FIG.

Hereinafter, an example of the manufacturing method will be described with reference to FIGS. In FIG. 3 as well, the same parts as those shown in FIG. 1 are denoted by the same reference numerals as those shown in FIG. 1, and redundant description is omitted.

(1) The insulating substrate 1 is sufficiently washed with a detergent, pure water, an organic solvent, and the like, and an oxide film 6 is formed on the substrate 1 by a sputter deposition method (FIG. 3A). . The formed oxide film 6 contains a metal oxide as a main component and may partially contain a carbonate or a hydroxide. However, when carbonates and hydroxides are heated, they generally turn into oxides, and the final melting point (or sublimation point) is determined by the state of the oxides, so that there is no particular problem. Also,
The method of forming the oxide thin film 6 is not limited to the sputter deposition method, and may be formed by an alkoxide-based coating material such as another vacuum deposition method, an electron beam deposition method, or a CVD method.

(2) Appropriate patterning is performed by photolithography, the device electrodes 2 and 3 are formed by vapor deposition, and an organic metal solution is applied to the substrate 1 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, patterned by lift-off, etching, etc.,
A conductive thin film 4 is formed (FIG. 3B). Here, the method of applying the organometallic solution has been described.
The method for forming is not limited to this, and a vacuum deposition method, a sputtering method, a chemical vapor deposition method, a dispersion coating method, a dipping method, a spinner method, or the like can also be used.

(3) Subsequently, a forming step is performed.
As an example of the method of the forming step, a method by an energization forming process will be described. When current is applied between the device electrodes 2 and 3 using a power supply (not shown), an electron emitting portion 5 having a changed structure is formed at the portion of the conductive thin film 4 (FIG. 3C). According to the energization forming, a portion where the structure such as destruction, deformation or alteration is locally formed in the conductive thin film 4 is formed. This portion constitutes the electron emission section 5. Further, when the oxide film 6 is formed before the energization forming, the oxide film 6 may also locally cause structural changes such as destruction, deformation or alteration at the same time.

FIG. 4 shows an example of a voltage waveform applied to the element electrodes 2 and 3 during energization forming.

The voltage waveform is preferably a pulse waveform. For this, a method of applying a waveform voltage shown in FIG.
There is a method of applying the voltage pulse shown in FIG. 4B in which the voltage pulse is applied while increasing the pulse peak value.

T1 and T2 in FIG. 4A are the pulse width and pulse interval of the voltage waveform. Usually, T1 is set in the range of 1 microsecond to 10 milliseconds, and T2 is set in the range of 10 microseconds to 100 milliseconds. The peak value of the triangular wave (peak voltage at the time of 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.

T1 and T2 in FIG.
It can be similar to that shown in FIG. The peak value of the triangular wave (peak voltage during energization forming) can be increased, for example, by about 0.1 V steps.

The end of the energization forming process can be detected by applying a voltage that does not locally destroy or deform the conductive thin film 2 during the pulse interval T2, and measuring the current. For example, an element current flowing by applying a voltage of about 0.1 V is measured, and a resistance value is obtained. When the resistance value indicates 1 MΩ or more, the energization forming is terminated.

(4) It is preferable to perform a process called an activation process on the device after the forming process. 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 the 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 once sufficiently evacuated by an ion pump or the like. It can also be obtained by introducing a gas of an appropriate organic substance into a vacuum. 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. Suitable organic substances include alkane, alkene, alkyne aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, aldehydes, ketones, amines, nitriles, phenols, carboxylic acids, and organic acids such as sulfonic acids. And specifically, C _n H such as methane, ethane, and propane.
Saturated hydrocarbon represented by _{2n + 2,} ethylene, propylene C _n H _2n such unsaturated hydrocarbon represented by composition formula such as benzene, toluene, methanol, ethanol, formaldehyde, acetaldehyde, acetone, methyl ethyl ketone, methyl amine , Ethylamine, phenol, benzonitrile, acetonitrile, formic acid, acetic acid, propionic acid and the like. 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 termination of the activation step is appropriately determined 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.

The carbon and the carbon compound include, for example, graphite (HOPG, PG, GC,
PG is an almost perfect graphite crystal structure, PG is a crystal grain having a crystal grain size of about 20 nm and slightly disordered, and GC is a crystal grain having a grain size of about 2 nm and disordered crystal structure is further increased.) Crystalline carbon (refers to amorphous carbon and a mixture of amorphous carbon and the microcrystals of graphite), and has a film thickness of 50
nm or less, and more preferably 30 nm or less.

(5) The electron-emitting device obtained through such a step is preferably subjected to a stabilization step. This stabilization step is a step of exhausting organic substances in the vacuum vessel. The pressure in the vacuum vessel is preferably 1 to 3 × 10 ⁻⁷ Torr or less, and more preferably 1 × 10 ⁻⁸ Torr or less. 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 and an ion pump can be used. Further, when evacuating the inside of the vacuum vessel, the entire vacuum vessel is heated, and the inner wall of the vacuum vessel,
It is preferable that the organic substance molecules adsorbed on the electron-emitting device be easily exhausted. The heating condition at this time is 80 to 200 ° C.
5 hours or more is desirable, but the conditions are not particularly limited, and the conditions are appropriately selected depending on various conditions such as the size and shape of the vacuum vessel and the configuration of the electron-emitting device.

The atmosphere at the time of driving after the stabilization step is preferably the same as the atmosphere at the end of the stabilization treatment, but is not limited to this, as long as the organic substance is sufficiently removed. Even though 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.

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. 5 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. Also 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, 1 is a substrate constituting an electron-emitting device, 2 and 3 are device electrodes, 4 is a conductive thin film, 5 is an electron-emitting portion, and 6 is an oxide film. Reference numeral 51 denotes a power supply for applying a device voltage Vf to the electron-emitting device, and reference numeral 50 denotes a device current If flowing through the conductive thin film 4 between the device electrodes 2 and 3.
Is an anode electrode for capturing the 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 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 m.
Measurements can be made in the range of m to 8 mm.

The vacuum container 55 is provided with equipment necessary for measurement in a vacuum atmosphere such as a vacuum gauge (not shown).
The measurement and evaluation can be performed in a desired vacuum atmosphere. The exhaust pump 56 is composed of a normal high vacuum system such as a turbo pump and a rotary pump, and an ultrahigh vacuum system such as an ion pump.
The entire vacuum processing apparatus provided with the electron source substrate shown here can be heated to 200 ° C. by a heater (not shown).

FIG. 6 shows emission current Ie, device current If, and device voltage V measured using the vacuum processing apparatus shown in FIG.
It is the figure which showed the relationship of f typically. In FIG.
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 apparent from FIG. 6, the surface conduction electron-emitting device to which the present invention can be applied has three characteristic properties with respect to the emission current Ie.

That is, (i) the emission current Ie of the present device increases sharply when a device voltage higher than a certain voltage (referred to as a threshold voltage) is applied, whereas when the device voltage is lower than the threshold voltage Vth, the emission current Ie hardly increases. Not detected. That is, the emission current I
This is a non-linear element having a clear threshold voltage Vth for e.

(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 depends on the time during which the device voltage Vf is applied. 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 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. 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 is equal to the element voltage Vf.
May exhibit a voltage control type negative resistance characteristic (hereinafter, referred to as “VCNR characteristic”) in some cases (not shown). These properties can be controlled by controlling the steps described above.

FIG. 7 shows a time change of the emission current Ie when the device is driven for a long time at a constant device voltage Vf applied between the device electrodes. In the figure, the solid line indicates the electron-emitting device according to the present invention, and the broken line indicates the oxide film 6.
Is a device for comparison without forming the same. The half emission time of the emission current Ie at the time of manufacture is presented for reference.

According to the present invention, the oxide film 6 formed between the substrate 1 and the electron-emitting portion 5 makes it possible to produce an electron source capable of extracting a high electron-emitting current. An extremely high-brightness electron-emitting device can be formed.

As described above, since the electron-emitting device according to the present invention has stable and high-luminance electron emission characteristics for a long time, it can be expected to be applied to various fields.

(Application Example of Electron-Emitting Element) An application example of an electron-emitting element to which the present invention can be applied will be described below. By arranging a plurality of surface conduction electron-emitting devices to which the present invention can be applied 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 employed.

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 (column direction). There is a ladder arrangement in which electrons from the electron-emitting devices are controlled and driven by control electrodes (also called grids) arranged above the electron-emitting devices. Separately, 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 commonly connected to a wiring in the X direction. One example is one in which the other of the electrodes of a plurality of electron-emitting devices arranged in the same column 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 the characteristics (i) to (iii) as described above. That is, when the electron emission from the surface conduction 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, a surface conduction electron-emitting device can be selected and the amount of electron emission can be controlled according to an input signal.

(Electron Source) 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. In FIG.
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-directional wirings 82 are DX ₁ , D
X ₂ ,. . Consists DX _m, a vacuum evaporation method, printing method, it can be composed of a formed conductive metal or the like by sputtering or the like. The material, thickness, and width of the wiring are appropriately designed. The Y-direction wiring 83 includes DY ₁ , DY ₂ ,. . It is composed of _n wirings DY _n and is formed in the same manner as the X-directional wiring 82. These m X-directional wirings 82 and n Y-directional wirings 8
3, an interlayer insulating layer (not shown) is provided.
Both are electrically separated (m and n are both positive integers).

An 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 manufacturing 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 to each other by a connection 85 made of a conductive metal or the like with m X-direction wires 82 and n Y-direction wires 83. 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 partially or entirely the same or different from each other. Good. 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.

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 is connected to the X-direction wiring 82. 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.

(Image Forming Apparatus) An image forming apparatus constructed using such an electron source having a simple matrix arrangement will be described with reference to FIGS. 9, 10 and 11. FIG. FIG.
Is a schematic diagram showing 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. 11 is a block diagram illustrating an example of a drive circuit for performing display in accordance with 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 as an adhesive. Reference numeral 98 denotes an envelope, for example, 400 to 5 in the atmosphere or in nitrogen.
Baking is performed for 10 minutes or more in a temperature range of 00 ° C. to form a seal.

Reference numeral 84 corresponds to the electron-emitting portion 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 is composed of 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 9 is sealed by the face plate 96, the support frame 92 and the substrate 81.
8 may be configured. On the other hand, by installing a support (not shown) called a spacer between the face plate 96 and the rear plate 91, an envelope 98 having sufficient strength against atmospheric pressure can be formed.

FIG. 10 is a schematic diagram showing a part of the fluorescent film 94. The fluorescent film 94 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 101 called a black stripe or a black matrix and a fluorescent material 102 depending on the arrangement of the fluorescent materials. 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 the case of color display, 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 95 is provided on the inner surface side of the fluorescent film 94. The purpose of providing the metal back 95 is to improve the brightness by mirror-reflecting the light emitted from the phosphor toward the inner surface side to the face plate 96 side, and to act as an electrode for applying an electron beam acceleration voltage. And protecting the phosphor from damage caused by the 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 96 is further provided with the 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. In this case, the metal back 95 may not be provided.

When sealing the envelope 98, in the case of color, the phosphors of each color must 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.

[0118] The envelope 98, 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 an organic substance having 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 because the getter arranged at a predetermined position (not shown) in the envelope 98 is heated by heating using resistance heating or high-frequency heating immediately before or after the envelope 98 is sealed. This is a process for forming a deposited film. A getter typically contains Ba as a principal component, the adsorption effect of the vapor deposition film, for example, 1 × 10 ^-5
Alternatively, a degree of vacuum of 1 × 10 ⁻⁷ Torr is maintained. Here, steps after the forming process of the surface conduction electron-emitting device can be appropriately set.

(Display Panel Driving Circuit) Next, a display panel constructed using electron sources arranged in a simple matrix has N
A configuration example of a driver circuit for performing television display based on a TSC television signal is described with reference to FIG. In FIG. 11, 111 is an image display panel,
112 is a scanning circuit, 113 is a control circuit, and 114 is a shift register. 115 is a line memory, 116 is a synchronizing signal separation circuit, 117 is a modulation signal generator, Vx and Va
Is a DC voltage source.

The display panel 111 has terminals Dox1 to Dox1
oxm, terminals Doy1 to Doyn, and high voltage terminal Hv
Connected to an external electric circuit via Terminal Dox1
Scanning for sequentially driving 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 at a time (N elements). A signal is applied.

To the terminals Dy1 to Dyn, a modulation signal for controlling an output electron beam of each element of one row of surface conduction electron-emitting devices selected by the scanning signal is applied. 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 inside (in the drawing, S1 to Sm are schematically shown). Each switching element is connected to the output voltage of the DC voltage source Vx or 0
[V] (ground level) is selected and electrically connected to the terminals Dx1 to Dxm of the display panel 111. Each of the switching elements S1 to Sm operates based on the 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 (electron emission threshold voltage) of the surface conduction electron-emitting device, and the driving voltage applied to the unscanned device is an 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 Tm to each unit based on the synchronization signal Tsync sent from the synchronization signal separation circuit 116.
ry 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 shown 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. (That is, 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 output from the shift register 114 as N parallel signals Id1 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 and input to the modulation signal generator 117.

Modulated signal generator 117 outputs image data I '.
The signal source is a signal source for appropriately driving and modulating each of the surface conduction electron-emitting devices in accordance with each of d1 to I'dn, and its output signal is supplied to the surface conduction electron-emitting device in the display panel 111 through terminals Doy1 to Doyn. Applied to the emitting element.

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, but when a voltage higher than 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. Also, the pulse width Pw
, It is possible to control the total amount of charges of the output electron beam. Therefore, a voltage modulation method, a pulse width modulation method, or the like can be adopted as a method of modulating the electron-emitting device according to the input signal. 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 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 type is used, it is necessary to convert the output signal DATA of the synchronizing signal separating circuit 116 into a digital signal. For this purpose, an A / D converter may be provided at the output of the synchronizing signal separating circuit 116. In connection with this, the line memory 11
Depending on whether the output signal of 5 is a digital signal or an analog signal,
The circuit used for modulation signal generator 117 is slightly different. 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 comparator for comparing the output value of the counter with the output value of the memory. (Comparator) is used. If necessary, an amplifier for voltage-amplifying 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, an amplification circuit using, for example, an operational amplifier can be used as the modulation signal generator 117, 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 (VCO) can be employed, and an amplifier for amplifying the voltage up to the drive voltage of the surface conduction electron-emitting device can be added as necessary.

In the image display device to which the present invention can be applied, which has such a configuration, by applying a voltage to each electron-emitting device via the external terminals Dox1 to Doxm and Doy1 to Doyn, the electron-emitting device can emit electrons. 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. The input signal is described in the NTSC system. However, the input signal is not limited to this. In addition to the PAL and SECAM systems, a TV signal including a larger number of scanning lines (for example, the MUSE system and the like) High-definition TV).

The image forming apparatus of the present invention can be 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. Can be used.

[0137]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to specific examples, but the present invention is not limited to these examples, and each element within a range in which the object of the present invention is achieved. This also includes those in which substitutions or design changes have been made.

[Embodiment 1] The basic structure of a surface conduction electron-emitting device according to the present invention is the same as the plan view and cross-sectional view of FIGS. 1 (a) and 1 (b).

The method for manufacturing the surface conduction electron-emitting device according to the present invention is basically the same as that shown in FIG. Hereinafter, FIG.
With reference to FIG. 3, the basic configuration and manufacturing method of the device according to the present invention will be described.

In FIG. 1, 1 is a substrate, 2 and 3 are device electrodes, 4 is a conductive thin film, 5 is an electron emitting portion, and 6 is an oxide film.

Hereinafter, the manufacturing method will be described in order with reference to FIG. 1 and FIG.

(Step-a) S
Using a cesium oxide coating material manufactured by YMETRIX,
Dip coating was performed at a lifting speed of 200 mm / min. After drying this substrate at 120 ° C. for 30 minutes,
Pre-baking was performed at 470 ° C. for 30 minutes, and main baking was performed at 550 ° C. for 60 minutes to form an oxide film 6 having a thickness of about 800 °.

(Step-b) On a substrate 1 on which a 0.5 μm thick silicon oxide film was formed by sputtering,
A pattern to be a gap L between the device electrodes 2 and 3 and a desired device electrode is formed by a photoresist (RD-2000N-41).
Hitachi Chemical Co., Ltd.), and 5 nm thick Ti and 100 nm thick Ni were sequentially deposited by a vacuum evaporation method. The photoresist pattern is dissolved with an organic solvent, the Ni / Ti deposited film is lifted off, and the device electrode interval L
Was 3 micrometers, and device electrodes 2 and 3 having a width W of the device electrode of 300 micrometers were formed.

(Step-c) The mask of the conductive thin film 4 of the electron-emitting device according to this step is a mask having an inter-electrode electrode gap L and an opening in the vicinity thereof. Meter Cr film is deposited and patterned by vacuum evaporation, and organic Pd (c
cp4230 (Okuno Pharmaceutical Co., Ltd.) was spin-coated with a spinner and heated and baked at 300 ° C. for 12 minutes. The conductive thin film 4 made of fine particles of palladium Pd as the main element thus formed has a thickness of 1%.
The sheet resistance was 0 × 10 nm and the sheet resistance was 2 × 10 ⁴ Ω / □. The fine particle film described here is, as described above, a film in which a plurality of fine particles are gathered, and as a fine structure, not only a state in which the fine particles are individually dispersed and arranged, but also the fine particles are adjacent to each other or overlap each other. A film in a state (including an island shape) is referred to, and the particle size refers to a diameter of a fine particle whose particle shape can be recognized in the state.

(Step-d) The Cr film and the fired conductive thin film 4 were etched with an acid etchant to form a desired pattern.

Through the above steps, the oxide layer 6, the device electrodes 2, 3 and the conductive thin film 4 were formed on the substrate 1.

(Step-e) Next, the device was set in the measurement and evaluation apparatus, evacuated by a vacuum pump, and after reaching a degree of vacuum of 2 × 10 ⁻⁵ Torr, a device for applying the device voltage Vf to the device was not used. A voltage was applied between the element electrodes 2 and 3 of the element from the power supply shown in the figure to perform energization forming. The voltage waveform of the energization forming process is that shown in FIG.

In the figure, T1 and T2 are the pulse width and pulse interval of the voltage waveform. In this embodiment, T1 is 1 millisecond, T1
2 was set to 10 milliseconds, and the peak value (peak voltage at the time of forming) of the rectangular wave was increased in steps of 0.1 V to perform the forming process. During the forming process, a resistance measurement pulse was inserted at T2 at a voltage of 0.1 V, and the resistance was measured. The forming process was terminated when the value measured by the resistance measurement pulse became about 1 M ohm or more, and at the same time, the application of the voltage to the element was terminated.

Thereafter, the device was kept in an ultra high vacuum of 1.0 × 10 ⁻⁹ Torr.

(Step-f) Subsequently, the tolunitrile sealed in an ampoule was introduced into a vacuum through a slow leak valve to maintain 1.0 × 10 ⁻⁶ Torr. Next, the element subjected to the forming process was subjected to an activation process with a peak value ± Vph of 14 V and an application period T1 and a period T2 with the waveform shown in FIG.

As described above, the activation process is performed as shown in FIG.
A pulse voltage was applied between the device electrodes while measuring the device current If and the emission current Ie at this time. Efficiency η (Ie × 100 / If)
(%) Reached a maximum in about 30 minutes, so the energization was stopped, the slow leak valve was closed, and the activation process was terminated.

(Step-g) Thus, the electron-emitting portion 5 is formed
And fabricated an electron-emitting device, and evaluated the electron-emitting characteristics (FIG. 7).
Valued. Note that the distance between the anode electrode and the electron-emitting device is
4 mm, anode electrode potential 1000 V, electron emission characteristics
The degree of vacuum in the vacuum device during the measurement of ^-8With Torr
Then, an element voltage of 14 V is applied between the electrodes 2 and 3 of the element.
Was. The device on which the oxide film 6 of the present embodiment is formed is shown in FIG.
As shown, the oxide film 6 used for comparison was not formed.
Compared with the device, the electron emission current Ie is clearly
They also have large initial values and high-brightness electron emission characteristics.
As shown in FIG. 7, the emission current Ie of the comparative device is reduced by half.
Also in the driving time, the emission current Ie of the device of this embodiment is
The value was larger and the degradation rate was smaller than before.

Further, as the material of the conductive thin film 4, the above P
Uses sputtered films of Pd, Ni, Pt, and Au in addition to dO
And the above-described Cs as the oxide thin film 6_TwoO, K
_TwoO, Na _TwoUsing a thin film of O oxide formed by CVD
The same effect can be obtained by various combinations
Was.

[Embodiment 2] In this embodiment, the basic structure of a surface conduction electron-emitting device according to the present invention is shown in FIG.
(A) and (b) are the same as the plan view and the sectional view. In order to use an unstable oxide film as the oxide film 6, the following device was devised.

(Step-a) First, a barium oxide coating material and a silicon oxide coating material manufactured by SYMETRIX were mixed, and the composition was appropriately adjusted so that the component ratio of the fired silicon oxide was 50% or more. . Using the above solution on a cleaned blue plate glass, a pulling speed of 200 mm / mi
n, dip coating was performed. This substrate is
After drying at 30 ° C. for 30 minutes, pre-baking was performed at 470 ° C. for 30 minutes, and main firing was performed at 550 ° C. for 60 minutes to form an oxide layer 6 having a thickness of about 80 nm.

From (Step-b) to (Step-g), the same steps as in Example 1 were performed.

Further, as the material of the conductive thin film 4, the above P
In addition to dO, a sputtered film of Pd, Ni, Pt, Au was used.
Various combinations using thin films formed by sputter deposition or CVD of oxides of CeO and MgO can also be used.
Similar effects were obtained.

As described above, also in this embodiment, stable electron emission characteristics were obtained for a long time.

[Embodiment 3] In this embodiment, an example of a display device configured to display image information provided from various image information sources such as television broadcasting will be described. Display was performed on the image forming apparatus shown in FIG. 9 using the drive circuit shown in FIG. 11 in accordance with an NTSC television signal.

In the present display device, the depth of the display device can be reduced particularly because the display panel using the surface conduction electron-emitting device as the electron beam source can be easily made thin. In addition, since the display panel using the surface conduction electron-emitting device as the electron beam source can be easily enlarged in size, has high brightness, and has excellent viewing angle characteristics, the present display device is full of presence and powerful. Image with good visibility,
It is possible to display.

The display device of this example was able to display a television image according to the NTSC television signal in a favorable state for a long time and stably.

[0162]

As described above, according to the surface conduction electron-emitting device of the present invention, an electron-emitting device capable of extracting a high electron-emitting current can be provided.

Furthermore, in an electron source that emits electrons in response to an input signal, a plurality of the above-described electron-emitting devices are arranged on a substrate to constitute an electron source. Have a plurality of rows of electron-emitting devices connected to the wiring, and further have an arrangement method having a modulating means, or a substrate having m X-directional wirings and n wirings electrically insulated from each other. By providing an electron source in which a plurality of electron-emitting devices in which a pair of device electrodes of the electron-emitting device are connected to the Y-direction wiring are arranged, each electron-emitting device has good electron emission characteristics. An electron source that can be held over time can be provided.

Further, in the image forming apparatus, since the image forming apparatus is composed of the image forming member and the electron source, and forms an image based on the input signal, the stability of the electron emission characteristics and the life are improved. In an image forming apparatus as an image forming member, a high-quality image forming apparatus, for example, a color flat television can be realized.

[Brief description of the drawings]

FIGS. 1A and 1B are a schematic plan view and a sectional view showing a configuration of a basic surface conduction electron-emitting device suitable for the present invention.

FIG. 2 is a schematic diagram showing a configuration of a basic vertical surface conduction electron-emitting device suitable for the present invention.

FIG. 3 is an example of a method for manufacturing a surface conduction electron-emitting device suitable for the present invention.

FIG. 4 is an example of a voltage waveform of energization forming suitable for the present invention.

FIG. 5 is a schematic configuration diagram of a measurement evaluation device for measuring electron emission characteristics.

FIG. 6 is a typical example of the relationship between the emission current Ie, the device current If, and the device voltage Vf of a surface conduction electron-emitting device suitable for the present invention.

FIG. 7 is a typical example showing a change of an emission current Ie depending on a driving time of a surface conduction electron-emitting device according to the present invention.

FIG. 8 shows an electron source in which the electron-emitting devices of the present invention are arranged in a simple matrix.

FIG. 9 is a schematic configuration diagram of a display panel of the image forming apparatus of the present invention.

FIG. 10 shows a fluorescent film used in the image forming apparatus of the present invention.

FIG. 11 is a block diagram of a driving circuit of an example in which an image forming apparatus performs display according to an NTSC television signal.

FIG. 12 shows an activation pulse shape suitable for the present invention.

FIG. 13 is a plan view of a conventional surface conduction electron-emitting device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Substrate 2, 3 Device electrode 4 Conductive thin film 5 Electron emission part or electron emission part forming material 6 Oxide thin film 21 Step formation part 50 For measuring device current If flowing through a conductive thin film between device electrodes 2 and 3. 51 A power supply for applying the device voltage Vf to the electron-emitting device 52 An ammeter for measuring the emission current Ie emitted from the electron-emitting portion of the device 53 A high-voltage power supply for applying a voltage to the anode 54 54 Anode electrode 55 Vacuum device 56 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 97 High pressure Terminal 98 envelope 101 black conductive material 102 phosphor 111 display panel 112 scanning circuit 11 The control circuit 114 the shift register 115 a line memory 116 synchronizing signal separation circuit 117 modulation signal generator Vx and Va dc voltage sources 151 interlayer insulating layer 152 contact hole 171 Cr film

Claims (13)

[Claims] 1. An electron-emitting device comprising: a pair of opposing element electrodes formed on an insulating substrate; and a conductive thin film having an electron-emitting portion formed between the pair of element electrodes, A material in which a layer formed between an insulating substrate and the electron-emitting portion contains a metal oxide, and at least a part of the metal oxide contains at least a material easily reduced by a reducing material such as carbon. An electron-emitting device characterized by comprising: 2. When the metal oxide is a single-component oxide, the value of the standard free energy of formation per mole of the single-component oxide is per mole of silica (SiO ₂ ) having the same temperature. 2. The electron-emitting device according to claim 1, wherein the absolute value is smaller than the value of the standard free energy of formation. 3. When the metal oxide is a composite oxide (base material + metal oxide), the value of the standard free energy of formation per mole of the composite oxide is equal to that of the base material at the same temperature. 3. The electron-emitting device according to claim 1, wherein the absolute value of the material is smaller than the value of the standard free energy of formation per mole of the material. 4. The method according to claim 1, wherein the metal oxide is an alkali metal (1A).
Group), alkaline earth metal (group 2A), group 6A, group 7A,
Group 8, 1B, 2B and Sn, Pb, Sb, Bi, P
2. The electron-emitting device according to claim 1, wherein at least a part of the metal oxide is a composite oxide contained in a base material such as silica. 3. 5. The electron-emitting device according to claim 4, wherein the material of the metal oxide is Cs ₂ O, K ₂ O, Na
₂ O, Cu ₂ O, BaO, CaO, MgO, SrO, P
bO, NiO, SnO, CoO, Cr 2 O 3, In 2 O
_{3, Fe 2 O 3, WO} 2, the electron-emitting device which is characterized in that any one of a single oxide of MnO ₂ or silica composite oxide of (SiO _2). 6. The electron-emitting device according to claim 3, wherein the base material is silica (SiO ₂ ).
An electron-emitting device comprising one of alumina (Al ₂ O ₃ ) and magnesia (MgO). 7. The electron-emitting device according to claim 1, wherein said electron-emitting device is a surface-conduction electron-emitting device. 8. An electron source which emits electrons in response to an input signal, wherein a plurality of the electron-emitting devices according to claim 1 are arranged on the insulating substrate. source. 9. An electron source according to claim 8, wherein a plurality of electron-emitting devices are arranged in parallel on said insulating substrate, and both ends of each of said electron-emitting devices are connected to a wiring. An electron source, comprising: a plurality of rows of elements; and a modulating means for modulating the input signal. 10. The electron source according to claim 9, wherein the m number of X-direction wirings and the n number of Y-direction wirings electrically insulated from each other are arranged on the insulating substrate. An electron source, wherein a plurality of the electron-emitting devices connected to a pair of device electrodes are arranged. 11. An image forming apparatus for forming an image based on an input signal, wherein the image forming member includes at least a fluorescent film facing the insulating substrate.
An image forming apparatus, comprising: the electron source according to (1). 12. A method for manufacturing an electron-emitting device comprising: a pair of opposing element electrodes formed on an insulating substrate; and a conductive thin film having an electron-emitting portion formed between the pair of element electrodes. Forming a layer containing a metal oxide between the insulating substrate and the electron-emitting portion, wherein a material contained in at least a part of the metal oxide is reduced by a reducing material such as carbon. A method for manufacturing an electron-emitting device. 13. When the metal oxide is a single composition oxide, silica (SiO ₂ ) having a standard free energy of formation per mole of the single composition oxide of the same temperature is used.
If the absolute value is smaller than the value of the standard free energy of formation per mole of the compound, or if the metal oxide is a composite oxide (base material + metal oxide), 13. The electron-emitting device according to claim 12, wherein the value of the standard free energy of formation is smaller than the value of the standard free energy of formation per mole of the base material at the same temperature. Manufacturing method.