JPH09293448A - Electron emitting element, electron source and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron source in which a plurality of electron emitting elements have a uniform electron emitting characteristic by forming an insulating substrate of an activation promoting layer and an activation restraining layer laminated on the promoting layer. SOLUTION: An electron emitting element comprises, on an insulating substrate 10, a pair of element electrodes 4, 5 disposed opposite to each other, and a conductive thin film 6 interposed between the electrodes 4, 5 and provided with an electron emitter 7. The substrate 10 is constituted by laminating, on a base 1, an activation promoting layer 3 having a thermoconductivity lower than that of an activation restraining layer 2 on the restraining layer 2 made of an excellent thermoconductive insulating material. The base 1 is preferably made of quartz glass, glass including a reduced quantity of impurity, ceramics, an Si substrate or the like; the restraining layer 2, of oxides such as aluminum oxide or nitride such as silicon nitride; the promoting layer 3, of SiO2 or glass including mainly SiO2 ; and the thin film 6, a particulate film composed of particles. The emitter 7 is formed of a crack of high resistance generated by energizing a part of the thin film 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron-emitting device, 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, two types of electron-emitting devices are known, which are roughly classified into a thermoelectron-emitting device and a cold cathode electron-emitting device. The cold cathode electron-emitting device includes a field emission type (hereinafter referred to as “FE type”), metal / insulating layer /
There are a metal type (hereinafter referred to as “MIM type”), a surface conduction electron-emitting device, and the like.

[0003] As an example of the FE type, W. P. Dyke &
W. W. Dolan, "Fielddemissio
n ", Advance in Electron Ph
ysics, 8, 89 (1956), or C.I.
A. Spindt, "PHYSICAL Proper
ties of thin-film field e
Mission cathodes with mol
ybdenium cones ”, J. Appl. Ph
ys. , 47, 5248 (1976).

An example of the MIM type is C.I. A. Mea
d, "Operation of Tunnel-Em
"Ission Devices", J.Apply.P
hys. , 32, 646 (1961) and the like are known.

Examples of the surface conduction electron-emitting device type include:
M. I. Elinson, Radio Eng. Ele
ctron Pys. 10, 1290, (1965)
Etc. have been disclosed. The surface conduction electron-emitting device utilizes a phenomenon in which electron emission occurs when a current is applied to a thin film having a small area formed on a substrate in parallel with the film surface. As this surface conduction electron-emitting device,
Using the SnO ₂ thin film by Erinson et al., A
u thin film [G. Dittmer: "Thin
Solid Films ", 9, 317 (197)
2)], an In ₂ O ₃ / SnO ₂ thin film [M. H
artwell and C.I. G. FIG. Fonstad: "
IEEE Trans. ED Conf. "519
(1975)], by a carbon thin film [Hiraki Araki
Others: Vacuum, Vol. 26, No. 1, p. 22 (1983)] and the like are reported.

FIG. 14 schematically shows an example of the structure of the surface conduction electron-emitting device. FIG. 14A is a schematic plan view,
(B) is a typical sectional view. In FIG. 1, reference numeral 1 denotes a substrate. Reference numeral 6 denotes a conductive thin film, and the electron emission portion 7 is formed by an energization process called energization forming described later.

In the surface conduction electron-emitting device, it is general that the electron-emitting portion 7 is formed in advance by conducting a current called a conductive forming process on the conductive thin film 6 before emitting electrons. That is, the energization forming means that a direct current voltage or a very slow rising voltage, for example, about 1 V / min is applied to the conductive thin film 6 or a pulse voltage is applied to locally break the conductive thin film. This is to form the electron-emitting portion 7 which is deformed or altered to have an electrically high resistance state. In the electron emitting portion 7, a structural change such as a crack occurs in a part of the conductive thin film 6, and electrons are emitted from the vicinity of the crack. In order to further increase the amount of emission current, energize in a hydrocarbon-based gas,
Perform activation processing. The surface conduction electron-emitting device that has been subjected to the energization forming process and the activation process is one in which electrons are emitted from the electron-emitting portion 7 by applying a voltage to the conductive thin film 6 and causing a current to flow through the device. .

[0008]

With respect to the electron-emitting device, it is necessary to further improve stable electron-emitting characteristics and efficiency of electron emission so that an image forming apparatus to which the electron-emitting device is applied can stably provide a bright display image. Is requested. The efficiency here is defined as the current flowing between the pair of device electrodes of the surface conduction electron-emitting device (hereinafter,
It is called "element current". ) And the current emitted in a vacuum (hereinafter referred to as "electron emission current"), and an electron-emitting device having a small device current and a large emission current is desired. If stable controllable electron emission characteristics and efficiency are improved, a bright, high-quality image forming apparatus with low current, such as a flat television, can be realized in an image forming apparatus using, for example, a phosphor as an image forming member. . Further, along with the reduction in current, it is possible to reduce the cost of the drive circuit and the like that form the image forming apparatus.

However, the emission current amount of the surface conduction electron-emitting device is rather decreased as the activation time becomes longer as shown in FIG. The individual surface conduction electron-emitting devices have different activation characteristics because the initial emission current is not uniform and the gas pressure during activation is different depending on the location. That is, if the activation is performed for the same time, the efficiency will vary depending on the device. Therefore, when using a plurality of surface conduction electron-emitting devices to configure an electron source or an image forming apparatus,
If the efficiencies of the individual electron-emitting devices are not uniform, there are problems that the amount of electron emission changes depending on the position and uneven brightness occurs.

[Object of the Invention] An object of the present invention is to provide an electron source in which a plurality of electron-emitting devices have uniform electron emission characteristics, and to use the electron source to form an image with uniform brightness and excellent operation stability. To provide a device.

[0011]

As a means for solving the above-mentioned problems, the present invention provides a pair of element electrodes provided on an insulating substrate so as to face each other and provided between the element electrodes. And a conductive thin film having an electron emitting portion, wherein the insulating substrate has an activation suppressing layer and an activation promoting layer formed on the layer. The present invention provides an electron-emitting device characterized by:

Further, the activation suppressing layer is also an electron-emitting device characterized in that it is a good thermal conductive insulator.

Also, the electron-emitting device is characterized in that the activation promoting layer is made of glass.

The insulating substrate is formed by sequentially stacking an activation suppressing layer made of a good thermal conductive insulator and an activation accelerating layer having a lower thermal conductivity than the layer on a substrate. It is also an electron-emitting device characterized by the above.

Also, the electron-emitting device is characterized in that the conductive thin film is an aggregate of fine particles.

The electron-emitting device is also an electron-emitting device characterized in that it is a surface conduction electron-emitting device.

The present invention also provides the above electron-emitting device,
An electron source having at least one row of a plurality of elements arranged in parallel and connected, and wiring for driving each element arranged in a ladder shape. It is a means for solving the problem.

Further, the electron-emitting device is arranged in the X direction and the Y direction.
One of the electrodes of the plurality of electron-emitting devices arranged in a matrix in the same direction and arranged in the same row is commonly connected to the wiring in the X direction, and the plurality of electron-emitting devices arranged in the same column. The other of the electrodes is also an electron source characterized in that it is commonly connected to a wiring in the Y direction.

The present invention further provides an image forming apparatus characterized in that the electron source and the image forming member are arranged so as to face each other, and an image is formed based on an input signal. It is also a means for solving the problems.

[Operation] According to the present invention, the activation step is formed by forming the activation promoting layer on the activation suppressing layer having good thermal conductivity and forming the electron-emitting device on the activation promoting layer. In the above, since it is possible to suppress the deterioration of the characteristics due to excessive activation and to make the activation uniform, it is possible to form an electron-emitting device having a uniform emission current.

Further, also in the electron source in which a plurality of the electron-emitting devices of the present invention are arranged, the electron-emitting property can be obtained with little variation in the electron-emitting properties depending on the position of the electron-emitting devices.

Further, in the image forming apparatus using the electron source of the present invention, it is possible to obtain an image forming apparatus having less unevenness in brightness, uniform brightness and excellent operation stability.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view showing the structure of a surface conduction electron-emitting device to which the present invention can be applied. FIG. 1 (a) is a schematic plan view and FIG. 1 (b) is a schematic sectional view. is there. In FIG. 1, 1 is a substrate, 2 is an activation suppressing layer formed on the substrate 1, 3 is an activation promoting layer formed on the activation suppressing layer, 4
5 and 5 are device electrodes, 6 is a conductive thin film, and 7 is an electron emitting portion. Further, 10 indicates a substrate on which the activation suppressing layer and the activation promoting layer are formed.

As the substrate 1, quartz glass, glass with a reduced content of impurities such as Na, soda lime glass, ceramics such as alumina, and Si substrate can be used.

As the activation suppressing layer 2, a good heat conductive insulator such as an oxide such as aluminum oxide, tantalum oxide or titanium oxide, or a nitride such as silicon nitride, aluminum nitride or tantalum nitride can be used.

Further, as the activation promoting layer 3, SiO ₂ ,
Glass having SiO ₂ as a main component is preferable. The activation promoting layer should be an electrically insulating material.

Further, the invention is characterized in that an activation promoting layer and an activation suppressing layer having better thermal conductivity than that of the layer are laminated.

Here, the activation step means a step of forming an electron emission state after the forming step, which will be described in detail below. For example, the element is exposed to an element in an atmosphere containing a gas of an organic substance. This can be performed by repeating the application of the pulse voltage.

By this treatment, carbon or a carbon compound is deposited on the device from the organic substance existing in the atmosphere,
The device current If and the emission current Ie change remarkably.

The activation-promoting layer enables activation by its presence, and the activation-suppressing layer does not activate or slows the activation speed by this layer. . It is not clear what kind of physical property determines the phenomenon that it is easy to activate or difficult to activate,
It tends to be difficult to activate in a material having good thermal conductivity and in which heat easily escapes to the substrate.

As a method of forming the activation suppressing layer 2 and the activation promoting layer 3, a usual thin film forming method can be applied. That is, a vacuum deposition method, a sputtering method, a CVD method, a sol-gel method or the like is used.

It is considered that there is no upper limit to the thickness of the activation suppressing layer 2, but if the thickness of the activation promoting layer 3 is too thick, the effect of the lower activation suppressing layer will be hidden, so 0.2. It is desirable that the diameter is less than micron, and preferably 0.1 μm.
The following is good.

The material of the opposing device electrodes 4, 5 is as follows:
General conductor materials can be used. This is, for example, Ni, Cr, Au, Mo, W, Pt, Ti, Al,
Metals or alloys such as Cu and Pd and Pd, Ag, Au and R
Select appropriately from printed conductors composed of metal or metal oxide such as uO ₂ , Pd-Ag and glass, transparent conductors such as In ₂ O ₃ -SnO ₂ and semiconductor conductor materials such as polysilicon. You can

The element electrode spacing L, the element electrode length W, the shape of the conductive thin film 6 and the like are designed in consideration of the applied form and the like.

The element electrode spacing L is preferably in the range of several hundred nm to several hundred μm, and more preferably,
In consideration of the voltage applied between the device electrodes and the like, the range can be set to several μm to several tens μm.

The element electrode length W is the resistance value of the electrode,
In consideration of electron emission characteristics, the thickness can be set in the range of several μm to several hundred μm.

The film thickness d of the device electrode can be in the range of several tens nm to several μm.

For the conductive thin film 6, it is preferable to use a fine particle film composed of fine particles in order to obtain good electron emission characteristics. The film thickness is appropriately set in consideration of the step coverage to the element electrodes 4 and 5, the resistance value between the element electrodes 4 and 5, and the forming conditions described later, etc.
The thickness is preferably in the range of 1 nm to several hundreds of 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 a value that appears when the resistance R measured in the length direction of a thin film having a thickness of t, a width of w, and a length of 1 is R = Rs (l / w).

In the present specification, the forming process will be described by taking an energizing process as an example. However, the forming process is not limited to this, and a structural change such as a crack is generated in the film to cause a high resistance state. Is included.

The materials forming the conductive thin film 6 are Pd and P.
t, Ru, Ag, Au, Ti, In, Cu, Cr, F
e, Zn, Sn, Ta, W, Pb and other metals, PdO, S
oxides such as nO ₂ , In ₂ O ₃ , PbO and Sb ₂ O ₃ ;
HfB ₂ , ZrB ₂ , LaB ₆ , CeB ₆ , YB ₄ , G
borides such as dB ₄ , TiC, ZrC, HfC, TaC,
It is appropriately selected from carbides such as SiC and WC, nitrides such as TiN, ZrN and HfN, semiconductors such as Si and Ge, and carbon.

The fine particle film described here is a film in which a plurality of fine particles are aggregated, and its fine structure has a state in which fine particles are individually dispersed and arranged, or a state in which fine particles are adjacent to each other or overlap each other (some fine particles are It also includes the case where they are aggregated to form an island structure as a whole). The particle size of the fine particles is in the range of 1 nm to several hundred nm, preferably in the range of 1 nm to 20 nm.

The term "fine particles" is frequently used in this specification, and its meaning will be described.

Small particles are called "fine particles", and particles smaller than this are called "ultrafine 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 for classification. 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.

In "Experimental Physics Course 14 Surfaces and Fine Particles" (edited by Yoshio Kinoshita, Kyoritsu Shuppan, published September 1, 1986), the following description is made.

"In the present specification, the term" fine particles "refers to particles having a diameter of about 2 to 3 µm to about 10 nm, and particularly, the term" fine particles "refers to particles having a 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 from 2 to several tens to several hundreds, it is called a cluster. (Page 195, lines 22-26).

In addition, the definition of "ultrafine particles" in "Hayashi / ultrafine particle project" of the New Technology Development Corporation was as follows, with the lower limit of the particle size being smaller.

In the "Ultrafine particle project" (1981-1986) of the creative science and technology promotion system, particles having a size (diameter) in the range of about 1 to 100 nm are called "ultrafine particles". Then, one ultrafine particle is about 100-
This is an aggregate of about 10 ⁸ atoms. Ultra-fine particles are large to giant particles on an atomic scale. "
("Ultrafine Particles-Creative Science and Technology", Ryuji Hayashi, edited by Ryoji Ueda, Akira Tasaki; Mita Publishing, 1988, page 2, lines 1 to 4) "Even smaller than ultrafine particles, that is, several to several hundred atoms A single particle composed is usually called a cluster "(ibid., Page 2, lines 12-13).

[0050] Based on the general notation as described above,
In the present specification, "fine particles" are aggregates of a large number of atoms and molecules, and the lower limit of the particle size is several times 0.1 nm to 1 nm,
The upper limit shall be about several μm.

The electron-emitting portion 7 is composed of a high-resistance crack or the like formed in a part of the conductive thin film 6, and is suitable for the film thickness, film quality and material of the conductive thin film 6 and a method such as energization forming described later. It depends. In some cases, conductive fine particles having a particle size in the range of several nm to several tens of nm are present inside the electron emission portion 7. The conductive fine particles contain a part or all of the elements of the material forming the conductive thin film 6. The electron emitting portion 7 and the conductive thin film 6 in the vicinity thereof may contain carbon and a carbon compound.

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

An example of the manufacturing method will be described below with reference to FIGS. Also in FIG. 11, FIG.
The same parts as those shown in FIG. 2 are given the same reference numerals as those shown in FIG.

1) The substrate 1 is thoroughly washed with a detergent, pure water, an organic solvent and the like, and the activation suppressing layer 2 and the activation accelerating layer 3 are deposited on the surface thereof by a vacuum vapor deposition method, a sputtering method or the like. Next, after depositing a device electrode material by a vacuum evaporation method, a sputtering method or the like, the device electrodes 4, 5 are formed on the substrate by using, for example, a photolithography technique (FIG. 11).
(A)).

2) An organic metal solution is applied to the substrate provided with the device electrodes 4 and 5 to form an organic metal thin film.

As the organic metal solution, it is possible to use a solution of an organic metal compound whose main element is the metal of the material of the conductive film 6 described above. The organic metal thin film is heat-fired and patterned by lift-off, etching or the like to form the conductive thin film 6 (FIG. 11B).

Although the method of applying the organic metal solution has been described here, the method of forming the conductive thin film 6 is not limited to this, and a vacuum deposition method, a sputtering method, a chemical vapor deposition method, a dispersion method, or the like. A coating method, a dipping method, a spinner method, etc. can also be used.

3) Subsequently, a forming process is performed.
As an example of a method of the forming step, a method by an energization process will be described. When electricity is applied between the device electrodes 4 and 5 by using a power source (not shown), an electron emitting portion 7 having a changed structure is formed at a portion of the conductive thin film 6.

According to the energization forming, a site having a structural change such as breakage, deformation or alteration is locally formed in the conductive thin film 6. This portion constitutes the electron emitting portion 7.

FIG. 3 shows an example of the voltage waveform of energization forming. The voltage waveform is preferably a pulse waveform. For this, the method shown in FIG. 3 (a) in which a pulse having a constant pulse peak value is continuously applied, and the method shown in FIG. 3 (b) in which a voltage pulse is applied while increasing the pulse peak value are shown. There is a technique.

T1 and T2 in FIG. 3A 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 during energization forming) is appropriately selected according to the form of the surface conduction electron-emitting device. Under such conditions, for example, a voltage is applied for several seconds to several tens minutes. The pulse waveform is not limited to a triangular wave, and a desired waveform such as a rectangular wave can be adopted.

T1 and T2 in FIG. 3B are the same as those 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 break or deform the conductive thin film 2 during the pulse interval T2 and measure the current. For example, the device current flowing by applying a voltage of about 0.1 V is measured, the resistance value is obtained, and when the resistance is 1 MΩ or more, the energization forming is terminated.

4) After the forming, the element is subjected to a process called an activation process. The activation process is a process in which the device current If and the emission current Ie are significantly changed by this process.

The activation step can be carried out, for example, by repeating the application of the pulse in the atmosphere containing the gas of the organic substance, similarly to the energization forming. This atmosphere can be formed by using an organic gas remaining in the atmosphere when the inside of the vacuum vessel is evacuated using, for example, an oil diffusion pump or a rotary pump, or is sufficiently evacuated once 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 appropriately set according to the case. Suitable organic materials include
Alkanes, alkenes, aliphatic hydrocarbons of alkynes, aromatic hydrocarbons, alcohols, aldehydes, ketones, amines, phenols, carboxyls, organic acids such as sulfonic acids and the like can be mentioned. Is methane,
Saturated hydrocarbons represented by C _n H _{2n + 2} such as ethane and propane, unsaturated hydrocarbons represented by a composition formula such as C _n H _2n such as ethylene and propylene, benzene, toluene, methanol, ethanol, formaldehyde and acetaldehyde , Acetone, methyl ethyl ketone, methylamine, ethylamine, phenol, formic acid, acetic acid, propionic acid and the like can be used. By this treatment, carbon or a carbon compound is deposited on the device from the organic substance existing in the atmosphere, and the device current If and the emission current Ie are significantly changed.

The termination of the activation process 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 are, for example, graphite (so-called HOPG, PG and GC, HO,
PG is an almost perfect crystal structure of graphite, PG is a crystal grain with a grain size of about 20 nm and the crystal structure is slightly disordered, GC
Indicates that the crystal grain becomes about 2 nm and the disorder of the crystal structure is further increased. ), Amorphous carbon (referring to amorphous carbon and a mixture of amorphous carbon and fine crystals of graphite), and its film thickness is
The range is preferably 50 nm or less, and more preferably 30 nm or less.

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

When an oil diffusion pump or a rotary pump is used as an exhaust device in the activation step and an organic gas derived from an oil component generated from the oil diffusion pump is used, it is necessary to suppress the partial pressure of this component as low as possible. . The partial pressure of the organic component in the vacuum container is preferably 1 × 10 ⁻⁵ Pa or less, and more preferably 1 × 10 ⁻⁷ Pa or less, in ^{terms of the} partial pressure at which the above-mentioned carbon and carbon compound are not newly deposited. When further evacuating the inside of the vacuum vessel, heat the entire vacuum vessel,
It is preferable to easily exhaust the organic substance molecules adsorbed on the inner wall of the vacuum container or the electron-emitting device. The heating condition at this time is preferably 80 to 400 ° C. and the treatment is preferably performed for as long as possible, but the heating condition is not particularly limited to this condition, and may be changed depending on various conditions such as the size and shape of the vacuum container and the configuration of the electron-emitting device. Perform according to the selected conditions. The pressure in the vacuum container is required to be as low as possible, preferably 1 × 10 ⁻⁵ Pa or less, and more preferably 1 × 10 ⁻⁶ Pa or less.

The atmosphere at the time of driving after carrying out the stabilizing step is preferably maintained at the atmosphere at the end of the stabilizing treatment, but it is not limited to this, and if the organic substance is sufficiently removed. Even if the degree of vacuum itself is slightly lowered, it is possible to maintain sufficiently stable characteristics.

By adopting such a vacuum atmosphere, the deposition of new carbon or carbon compound can be suppressed,
As a result, the device current If and the emission current Ie are stabilized.
The basic characteristics of the electron-emitting device to which the present invention is applicable obtained through the above steps will be described with reference to FIGS. 4 and 5. FIG. 4 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. 4, the same parts as those shown in FIG. 1 are denoted by the same reference numerals as those shown in FIG. In FIG. 4, reference numeral 45 denotes a vacuum vessel, and reference numeral 46 denotes an exhaust pump. An electron-emitting device is arranged in the vacuum container 45. That is, 1 is a substrate that constitutes an electron-emitting device, 4 and 5 are device electrodes, 6 is a conductive thin film, and 7 is an electron-emitting portion. 41 is a power source for applying a device voltage Vf to the electron-emitting device, 40 is an ammeter for measuring a device current If flowing through the conductive thin film 6 between the device electrodes 4, 5, and 4
Reference numeral 4 denotes an anode electrode for capturing an emission current Ie emitted from the electron emission portion of the device. 43 is a high voltage power supply for applying a voltage to the anode electrode 44, and 42 is an ammeter for measuring the emission current Ie emitted from the electron emission portion 7 of the device. As an example, the voltage of the anode electrode is set to 1
The measurement can be performed with the range of 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 container 45, equipment necessary for measurement in a vacuum atmosphere such as a vacuum gauge (not shown) is provided.
The measurement and evaluation can be performed in a desired vacuum atmosphere. The exhaust pump 46 is composed of a normal high vacuum system including a turbo pump and a rotary pump, and an ultrahigh vacuum system including an ion pump. The entire vacuum processing apparatus equipped with the electron source substrate shown here is
It can be heated by a heater (not shown). Therefore, by using this vacuum processing apparatus, the steps after the above-described energization forming can be performed.

FIG. 5 shows the emission current Ie, the device current If, and the 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. Incidentally. Both the vertical and horizontal axes are linear scales.

As is clear from FIG. 5, the surface conduction electron-emitting device to which the present invention is applied has three characteristic properties regarding the emission current Ie.

That is, (i) in this device, when a device voltage higher than a certain voltage (called a threshold voltage, Vth in FIG. 5) is applied, the emission current Ie rapidly increases, while the threshold voltage Vth is increased. In the following, the emission current Ie is hardly detected.
That is, a clear threshold voltage Vt with respect to the emission current Ie
It is a non-linear element having h. (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 44 is
It depends on the time for applying the element voltage Vf. That is, the amount of charge captured by the anode electrode 44 can be controlled by the time during which the device voltage Vf is applied.

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

Application examples of the electron-emitting device of the present invention will be described below. A plurality of surface conduction electron-emitting devices to which the present invention is applied are arranged on a substrate, for example, an electron source or
An image forming apparatus can be configured.

Various arrangements of electron-emitting devices can be adopted. As an example, as shown in FIG. 6, a large number of electron-emitting devices arranged in parallel are individually connected at both ends, and a large number of rows of the electron-emitting devices are arranged (referred to as a row direction). (Hereinafter referred to as “direction”), a control electrode (also referred to as a grid) arranged above the electron-emitting device controls the electrons from the electron-emitting device in a ladder-like arrangement. Separately from this, the electron-emitting device is arranged in the X direction and the Y
Electrodes of a plurality of electron-emitting devices arranged in the same row, one of the electrodes of a plurality of electron-emitting devices arranged in the same row being commonly connected to the wiring in the X direction. One of them is commonly connected to the wiring in the Y direction.
This is a so-called simple matrix arrangement.

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, the electrons emitted from the surface conduction electron-emitting device are
Above the threshold voltage, it can be controlled by the peak value and the width of the pulse voltage applied between the opposing element 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 pulsed voltage is appropriately applied to each device, a surface conduction electron-emitting device is selected according to an input signal to emit electrons. You can control the quantity.

Based on this principle, an electron source substrate obtained by arranging a plurality of electron-emitting devices to which the present invention can be applied will be described below with reference to FIG. In FIG. 7, reference numeral 71 denotes an electron source substrate, 72 denotes an X-direction wiring, and 73 denotes a Y-direction wiring.
74 is a surface conduction electron-emitting device, and 75 is a connection.

The m X-direction wirings 72 are Dx1 and Dx.
2 ,. . It is made of Dxm and can be made of a conductive metal or the like formed by a vacuum deposition method, a printing method, a sputtering method, or the like. The wiring material, film thickness, and width are appropriately designed.

The Y-direction wiring 73 is composed of Dy1, Dy2. . D
It is composed of n wirings of yn and is formed similarly to the X-direction wiring 72. An interlayer insulating layer (not shown) is provided between the m X-directional wirings 72 and the n Y-directional wirings 73 to electrically separate them (m and n are both Positive integer).

The interlayer insulating layer (not shown) is composed of SiO ₂ or the like formed by a vacuum vapor 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-direction wiring 72 is formed, and particularly, in order to withstand the potential difference at the intersection of the X-direction wiring 72 and the Y-direction wiring 73, the film thickness, The material and manufacturing method are appropriately set. The X-direction wiring 72 and the Y-direction wiring 73 are respectively drawn out as external terminals.

A pair of electrodes (not shown) forming the surface conduction electron-emitting device 74 are electrically connected to each other by m X-direction wirings 72, n Y-direction wirings 73, and a connection 75 made of a conductive metal or the like. It is connected.

The material forming the wiring 72 and the wiring 73, the material forming the connection 75, and the material forming the pair of element electrodes may be the same or different in some or all of the constituent elements. Good. These materials are appropriately selected, for example, from the above-described materials for the device electrodes. When the material forming the element electrode 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 74 arranged in the X direction is connected to the X-direction wiring 72. On the other hand, the Y-direction wiring 73 is connected to a modulation signal generating means (not shown) for modulating each column of the surface conduction electron-emitting devices 74 arranged in the Y direction according to an input signal.
The driving voltage applied to each electron-emitting device is supplied as a difference voltage between the scanning signal and the modulation signal applied to the device.

In the above structure, individual elements can be selected and driven independently by using simple matrix wiring. 8 and 9 show an image forming apparatus configured by using an electron source having such a simple matrix arrangement.
Also, description will be made with reference to FIG. 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.
Reference numeral 0 is a block diagram showing an example of a drive circuit for displaying according to an NTSC television signal.

In FIG. 8, 71 is an electron source substrate on which a plurality of electron-emitting devices are arranged, 81 is a rear plate on which the electron source substrate 71 is fixed, and 86 is 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. The rear plate 81 and the face plate 86 are connected to the support frame 82 by using frit glass or the like. Reference numeral 88 denotes an envelope, which is sealed and formed by firing in the temperature range of 400 to 500 ° C. for 10 minutes or more in the atmosphere or nitrogen.

Reference numeral 74 corresponds to the electron-emitting device in FIG. Reference numerals 72 and 73 are 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 88 is composed of 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, the face plate 86,
By installing a support body (not shown) called a spacer between the rear plates 81, it is possible to configure the envelope 88 having sufficient strength against atmospheric pressure.

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 mixed portions inconspicuous by making the painted portions between the phosphors 92 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 the material of the black stripe, in addition to a commonly used material containing graphite as a main component, a material having conductivity and having little light transmission and reflection can be used.

As a method for applying the phosphor to the glass substrate 83, a precipitation method, a printing method or the like can be adopted regardless 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 a metal back is
The light emitted from the phosphor toward the inner surface is converted into a face plate 8.
Improve brightness by specular reflection to the 6 side, act as an electrode for applying electron beam acceleration voltage, protect phosphor from damage due to collision of negative ions generated in the envelope, etc. It is. In the metal back, after the phosphor film is produced, the inner surface of the phosphor film is smoothed (usually called “filming”),
Thereafter, it can be manufactured by depositing Al using vacuum evaporation or the like.

The face plate 86 is further provided with 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-mentioned sealing, in the case of color, it is necessary to associate each color phosphor with the electron-emitting device.
Sufficient alignment is essential.

The image forming apparatus shown in FIG. 8 is manufactured, for example, as follows. The envelope 88 is exhausted through an exhaust pipe (not shown) by an exhaust device that does not use oil, such as an ion pump, a sorption pump, a turbo pump, and a cryopump, while appropriately heating, similarly to the stabilization process described above. The atmosphere is filled with a sufficiently small amount of organic substance having a vacuum degree of about 10 ⁻⁵ Pa, and then sealing is performed. A getter process can be performed to maintain the degree of vacuum after the envelope 88 is sealed. This is because a predetermined position (not shown) in the envelope 88 is obtained by heating using resistance heating or high frequency heating immediately before or after the envelope 88 is sealed.
This is a process of heating the getter arranged in the above to form a vapor deposition film. The getter usually has Ba or the like as a main component, and is, for example, 1 × 10 ⁻⁵ or 1 × due to the adsorption action of the deposited film.
The vacuum degree of 10 ⁻⁶ Pa is maintained. Here, steps after the forming process of the surface conduction electron-emitting device can be appropriately set.

Next, an example of the configuration of a drive circuit for performing television display based on NTSC television signals on a display panel configured using electron sources in a simple matrix arrangement will be described with reference to FIG. . In FIG.
101 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 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 the electron sources provided in the display panel, that is, the surface conduction electron-emitting device groups matrix-wired in a matrix of M rows and N columns row by row (N elements). A signal is applied.

A modulation signal for controlling the output electron beam of each element of the surface conduction electron-emitting devices of one row selected by the scanning signal is applied to the terminals Doy1 to Doyn. The high voltage terminal Hv is supplied with a DC voltage of, for example, 10 k [V] from the DC voltage source Va, which is sufficient to excite the phosphor into the electron beam emitted from the surface conduction electron-emitting device. It is an accelerating voltage for applying energy.

The scanning circuit 102 will be described. This circuit includes M switching elements inside (in the drawing, S1 to Sm are schematically shown). Each switching element selects either the output voltage of the DC voltage source Vx or 0 [V] (ground level),
It is electrically connected to terminals Dox1 to Doxm of the display panel 101. Each of the switching elements S1 to Sm operates based on the control signal Tscan output from the control circuit 103, and can be configured by combining switching elements such as FETs.

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

The control circuit 103 has a function of matching the operation of each unit so that an appropriate display is performed based on an image signal input from the outside. The control circuit 103 generates control signals Tscan, Tsft, and Tmry for each unit based on the synchronization signal Tsync sent from the synchronization signal separation circuit 106.

The sync signal separation circuit 106 is a circuit for separating a sync signal component and a luminance signal component from an NTSC television signal input from the outside, and uses a general frequency separation (filter) circuit or the like. Can be configured. The synchronizing signal separated by the synchronizing signal separating circuit 106 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 104.

The shift register 104 is for serial / parallel conversion of the DATA signal serially input in time series for each line of the image, and is based on the control signal Tsft sent from the control circuit 103. The control signal Tsft can be said to be the shift clock of the shift register 104. The serial / parallel converted image data for one line (corresponding to drive data for N electron emission elements) is output from the shift register 104 as N parallel signals Id1 to Idn.

The line memory 105 is a storage device for storing data for one line of an image for a required time, and stores the contents of Id1 to Idn as appropriate according to a control signal Tmry sent from the control circuit 103. The stored contents are output as I′d1 to I′dn and input to the modulation signal generator 107.

The modulation signal generator 107 outputs the image data I ′.
It is a signal source for appropriately driving and modulating each of the surface conduction electron-emitting devices according to each of d1 to I'dn, and the output signal is a surface conduction electron in the display panel 101 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 value, 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, no electron emission occurs even if a voltage below the electron emission threshold is applied, but an electron beam is output when a voltage above the electron emission threshold is applied. At this time, the pulse peak value V
By changing m, the intensity of the output electron beam can be controlled. Further, by changing the pulse width Pw, it is possible to control the total amount of charges of the output electron beam.

Therefore, as a method of modulating the electron-emitting device 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.

To implement the pulse width modulation method,
As the modulation signal generator 107, it is possible to use a circuit of a pulse width modulation system that generates a voltage pulse having a constant crest value and appropriately modulates the width of the voltage pulse according to input data.

The shift register 104 and the line memory 10
5 can be a digital signal type or an analog signal type. This is because the serial / parallel conversion and storage of the image signal may be performed at a predetermined speed.

When the digital signal type is used, it is necessary to convert the output signal DATA of the sync signal separation circuit 106 into a digital signal, which may be provided with an A / D converter at the output portion of 106. In connection with this, the line memory 10
Depending on whether the output signal of 5 is a digital signal or an analog signal,
The circuit used for modulation signal generator 107 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 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. A circuit that combines (comparators) is used. If necessary, an amplifier for amplifying the voltage of the pulse width modulated signal output from the comparator to the drive voltage of the surface conduction electron-emitting device can be added.

In the case of the voltage modulation method using an analog signal, the modulation signal generator 107 may be an amplifier circuit using an operational amplifier, for example, and a level shift circuit or the like may be added if necessary. In the case of the pulse width modulation method, for example, a voltage controlled oscillation circuit (VCO) can be adopted, and an amplifier for voltage amplification up to the drive voltage of the surface conduction electron-emitting device can be added if necessary.

In the image display device to which the present invention is applicable, which has the above-mentioned structure, the electron emission element is formed by applying a voltage to each electron-emitting device through the external terminals Dox1 to Doxm and Doy1 to Doyn. 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 the 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. As for the input signal, the NTSC system is mentioned, but the input signal is not limited to this, and other than the PAL, SECAM system, etc., a TV signal (eg, MUSE system, etc.) composed of a large number of scanning lines is used. High-definition TV) system can also be adopted.

The image forming apparatus of the present invention can be used not only as a display apparatus for television broadcasting, a display apparatus such as a TV conference system or a computer, but also as an image forming apparatus as an optical printer constituted by using a photosensitive drum or the like. Can be used.

[0115]

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 device used in this embodiment has a structure similar to that shown in FIG. 1, and is formed by arranging 48 devices in one row on one substrate. The manufacturing process of the electron-emitting device will be described with reference to FIG.

Step-a As an activation suppressing layer 2, a thickness of 2 is provided on the cleaned soda lime glass.
After forming an aluminum oxide film having a thickness of μm by the sputtering method, a silicon oxide film was formed as the activation promoting layer 3 by the sputtering method. Three types of substrates (samples a, b, and c) in which the thickness of the silicon oxide film was 0.1 μm, 0.05 μm, and 0.01 μm were prepared.

Step-b A mask pattern of photoresist (RD-2000N-41; manufactured by Hitachi Chemical Co., Ltd.) having openings corresponding to the electrode pattern is formed on the substrate, and the thickness thereof is 5 nm by a vacuum evaporation method.
Ti and Pt having a thickness of 100 nm are sequentially laminated. Dissolve the photoresist in an organic solvent, lift off the Pt / Ti film,
The device electrodes 4 and 5 were formed. The interval L between the device electrodes is 3μ
m, and the electrode width W is 300 μm (FIG. 11A).

Step-c A Cr film having a thickness of 100 nm is formed on the above-mentioned device by a vacuum deposition method, an opening corresponding to the pattern of the conductive thin film is formed by a photolithography technique, and a Cr mask for forming the conductive thin film is formed. To form.

An organic Pd solution (ccp4230; manufactured by Okuno Seiyaku Co., Ltd.) was applied to this using a spinner, and baked at 300 ° C. for 10 minutes in the atmosphere to form a fine particle film 6 containing PdO as a main component. The thickness of this film was 10 nm.

Step-d The Cr mask is removed by wet etching, and the PdO fine particle film is lifted off to obtain the conductive thin film 6 having a desired shape. The resistance value of the conductive thin film is Rs = 2 × 10
It was ⁴ Ω / □ (Fig. 11 (b)).

Step-e The substrate 10 was placed in the vacuum container 45 of the apparatus schematically shown in FIG. 4, and the vacuum container was evacuated by the exhaust device 46 to adjust the pressure to 1.3 × 10 ⁻³ Pa. The device used at this time is a so-called high vacuum exhaust device including a turbo pump and a rotary pump. In addition to this, the exhaust device 46 is provided with an ion pump for ultra-high vacuum, and can be used by appropriately switching.

A pulse voltage was applied to each element from the driving power source 41 to perform a forming process to form an electron emitting portion. The waveform of the pulse voltage at this time is a triangular wave pulse whose peak value gradually increases as shown in FIG. 3B, and the pulse width is T1 = 1 msec. , The pulse interval is T2 = 10 mse
c. And Further, during the forming process, a 0.1 V resistance measurement pulse was inserted within the pause time of the forming pulse, and the forming process was terminated when the resistance value exceeded 1 MΩ.

The peak value of the pulse at the end is 5.0 to 5.
It was 1V. The pressure inside the vacuum container at this time is 2.
It was 7 × 10 ⁻⁴ Pa.

Step-f Subsequently, an activation step was performed. The inside of the vacuum container 45 was once evacuated to about 10 ⁻⁶ Pa by an ion pump, and then the gas generator 47 and the flow rate adjusting valve 48 were controlled to introduce acetone to a pressure of 2.7 × 10 ⁻¹ Pa. It was adjusted so that At this time, at the same time, the drive circuit of the exhaust device was controlled to throttle the gate valve to adjust the exhaust speed.

The pulse applied to the element is a rectangular wave pulse having polarities alternately opposite to each other, and the pulse width is the same for both polarities. T1 = 1 msec. , The pulse interval is T2 = 10 msec. Therefore, one cycle is 20m
sec. The frequency was 50 Hz. Pulse peak value Va
ct is initially 10 V and 0.2 V / min. It was controlled so as to rise to 18 V and reach 18 V.

Samples a, b, having different activation promoting layer thicknesses
The relationship between the activation time of c and the efficiency is as shown in FIG. 12, and when the activation promoting layer is thick, the efficiency tends to decrease when activated for a long time.

Step-g Finally, stabilization was carried out at 250 ° C. for 12 hours in a vacuum of 10 ⁻⁵ Pa.

Thereafter, a 16 V triangular wave pulse is applied,
The electron emission characteristics were measured. The pressure in the vacuum container is 1.
3 × 10 ⁻⁶ Pa, the distance between the anode electrode and the electron-emitting device was 4 mm, and the potential difference was 1 kV. The variation in the emission current of the 48 electron-emitting devices is 10% for the samples a, b, and c.
It was 4% and 7%.

(Comparative Example) The same electron-emitting device as that of Example 1 was manufactured except that the aluminum oxide and silicon oxide films were not formed on the blue glass substrate. In this case, the variation in the emission current of the 48 devices was 16%.

Example 2 Forty-eight surface conduction electron-emitting devices were produced in the same manner as in Example 1 except that tantalum oxide was deposited as the activation suppressing layer by vacuum vapor deposition. The thickness of the activation promoting layer is 0.15 μm, 0.05 μm, 0.02
μm. The variations in the emission current of the 48 electron-emitting devices were 13%, 5%, and 6%, respectively.

Example 3 Forty-eight surface conduction electron-emitting devices were produced in the same manner as in Example 1 except that a silicon nitride film was deposited as the activation suppressing layer by the plasma CVD method. The thickness of the activation promoting layer is 0.2 μm, 0.07 μm,
It is. The variation of the emission current of the electron-emitting device is 14
% And 7%. As described above, the results of Examples 1 to 3 having the activation promoting layer and the activation suppressing layer of the present invention are all higher than the results of the comparative example having no activation promoting layer and the activation suppressing layer. There was little variation in emission current.

Further, in the above-mentioned embodiment, an example in which aluminum oxide, tantalum oxide, or silicon nitride is used as the activation suppressing layer has been described, but as described in the section of the embodiment,
Similarly, with titanium oxide, aluminum nitride or the like, it is possible to form an electron-emitting device with less variation in electron-emitting characteristics than the comparative example.

(Embodiment 4) This embodiment uses an electron source in which a plurality of surface conduction type transmission elements of the present invention are arranged on a substrate and are wired in a matrix as schematically shown in FIG. 7, and the electron source. It is an example in which the present invention is used for manufacturing an image display device.

The process will be described below with reference to the process diagram of FIG.

Step-A A layer having a thickness of 5 is formed on the cleaned soda-lime glass 1 by vacuum vapor deposition.
nm Cr and 600 nm thick Au are sequentially laminated,
A photoresist (AZ1370 manufactured by Hoechst) is spin-coated by a spinner, baked, and then exposed and developed with a photomask image to form a lower wiring pattern, and a Au / Cr deposited film is wet-etched to form a lower wiring of a desired shape. 72
Was formed (FIG. 13 (A)).

Step-B Next, an interlayer insulating layer 121 made of a silicon oxide film having a thickness of 1.0 μm was deposited by RF sputtering (FIG. 13).
(B)).

Step-C On the interlayer insulating layer 121, the aluminum oxide activation suppressing layer 2 and the silicon oxide film activation promoting layer 3 were formed by RF sputtering to have a thickness of 2 μm and 0.05 μm, respectively (FIG. 13C). .

Step-D A photoresist pattern for forming a contact hole 122 is formed in the silicon oxide film and the aluminum oxide film deposited in Steps B and C, and the interlayer insulating layer 121 is etched using this as a mask to etch the contact hole 122. Was formed. The etching is RI using CF ₄ and H ₂ gas.
It was based on the E (Reactive Ion Etching) method (FIG. 13 (D)).

Step-E After that, a pattern to be the device electrodes 4 and 5 and the gap G between the device electrodes is formed into a photoresist (RD-2000N-41).
・ Hitachi Chemical Co., Ltd.), and a thickness of 5 by vacuum evaporation method.
nm of Ti and 100 nm of Ni were sequentially deposited. Dissolve the photoresist pattern in an organic solvent, lift off the Ni / Ti deposited film, element electrode spacing 3 μm, width 300 μ
m element electrodes 4 and 5 were formed (FIG. 13E).

Step-F: A resist pattern is formed on a portion other than the contact hole 122 portion, and Ti having a thickness of 5 nm and a thickness of 500 are formed by vacuum evaporation.
nm of Au was sequentially deposited. Contact holes were buried by removing unnecessary portions by lift-off (FIG. 13F).

Step-G After forming the photoresist pattern of the upper wiring 73 on the device electrodes 4 and 5, Ti having a thickness of 5 nm and Au having a thickness of 500 nm are sequentially deposited by vacuum evaporation, and unnecessary portions are lifted off. Then, the upper wiring 73 having a desired shape was formed (FIG. 13G).

Step-H Next, a Cr film 124 having a thickness of 30 nm is deposited by vacuum evaporation and patterned so as to have an opening in the shape of the conductive thin film 6, and a Pd amine complex solution (ccp423) is formed thereon.
0) was spin-coated with a spinner and heated and baked at 300 ° C. for 12 minutes to form a conductive thin film 123 made of PdO fine particles. The film thickness of this film was 70 nm (FIG. 13 (H)).

Step-I The Cr film 124 was wet-etched using an etchant and removed together with unnecessary portions of the conductive film 123 of PdO fine particles to form the conductive thin film 6 having a desired shape. The resistance value was about Rs = 4 × 10 ⁴ Ω / □ (FIG. 13 (I)). Next, an example in which an image forming apparatus is configured using the electron source thus created will be described with reference to FIG.

Step-I After the electron source substrate 71 is fixed on the rear plate 81, a face plate 86 (a fluorescent film 84 and a metal back 85 are formed on the inner surface of the glass substrate 83 is formed 5 mm above the substrate 71. Is placed via a support frame 82, and frit glass is applied to the joint portion of the face plate 86, the support frame 82 and the rear plate 81, and the frit glass is applied at 400 ° C. for 10 hours in the atmosphere.
It was sealed by baking for a minute. Further, the frit glass was also used to fix the substrate 71 to the rear plate 81. In FIG. 8, 74 is an electron-emitting device, and 72 and 73 are device wirings in the X and Y directions, respectively.

In the case of monochrome, the fluorescent film 84 is composed of only the fluorescent material. In this embodiment, the fluorescent material has a stripe shape, a black stripe is first formed, and the fluorescent material of each color is applied to the gap. A fluorescent film 84 was produced. As a material for the black stripe, a material mainly containing graphite, which is commonly used, was used. Glass substrate 83
A slurry method was used as a method for applying the phosphor to the.

A metal back 85 is usually provided on the inner surface side of the fluorescent film 84. The metal back was manufactured by performing a smoothing process (usually called filming) on the inner surface of the fluorescent film after manufacturing the fluorescent film, and then vacuum-depositing Al.

The face plate 86 is further provided with 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 enhance the conductivity of No. 4, but in this embodiment, it was omitted because sufficient conductivity was obtained only by the metal back.

When performing the above-mentioned sealing, in the case of a color, it is necessary to make the respective color phosphors correspond to the electron-emitting devices, so that sufficient alignment was performed.

Step-J The atmosphere in the glass container completed as described above was evacuated to a vacuum degree of about 10 ^-4 Pa by a vacuum pump through an exhaust pipe (not shown). The Y-direction wirings are commonly connected and the forming process is performed for each line. Forming is Example 1
It was conducted under the conditions adopted in.

Step-K Subsequently, activation processing is performed. The exhaust pipe is connected to an ampoule filled with the activator acetone. Acetone is introduced into the panel, the pressure is adjusted to 1.3 × 10 ⁻¹ Pa, and a 18 V rectangular wave pulse is applied. The pulse width is 100 μsec. , The pulse interval is 20 msec. And

The activation process was executed line by line. The peak value Va is applied to one X-direction wiring connected to the elements in one row.
A rectangular wave pulse of ct = 18V is applied, and the Y-direction wiring is
Similar to step J, the common electrode is connected.

The pulse is changed to a triangular wave every one minute, and If
Measure the -Vf characteristic. The value of If at Vf2 = Vact / 2 = 9V is If (Vf2) ≧ If (Vact)
If it is / 220, the peak value of the square wave pulse for 30 seconds is 1
The voltage is raised to 9 V and then returned to 18 V to continue the activation process.

The device current per device is If (18V)
When ≧ 2 mA, the activation of the row is terminated, the activation processing of the next row is performed, and the same processing is repeated.

Step-L When the activation of all the rows was completed, the valve of the gas introduction device was closed to stop the introduction of acetone, and the entire glass panel was heated to about 200 ° C. and exhausted for 5 hours. By the way, by a simple matrix drive, electrons are emitted, the phosphor film is made to emit light over the entire surface, and after confirming that it operates normally, the exhaust pipe is heat-welded and sealed. After this,
A getter (not shown) installed in the panel by high frequency heating is flashed by high frequency heating.

Through the above steps, an image display device having practically sufficient brightness was manufactured, and the uneven brightness was suppressed to 12% or less.

[0157]

As described above, according to the electron-emitting device of the present invention, it is possible to provide the electron-emitting device having a high electron emission efficiency by suppressing the variation in the electron emission characteristics among the devices due to the variation in the manufacturing process. The effect is obtained.

That is, according to the present invention, the activation promoting layer is formed on the activation suppressing layer, and the electron-emitting device is formed on the activation promoting layer. It is considered that the deterioration of the characteristics is suppressed and the activation progresses to the same extent in any of the devices, so that it is possible to form an electron-emitting device having a uniform emission current.

Further, also in the electron source in which a plurality of the electron-emitting devices of the present invention are arranged, it is possible to obtain an electron source having a uniform electron-emitting characteristic with little variation due to the position of the electron-emitting devices.

Further, in the image forming apparatus using the electron source of the present invention, it is possible to obtain an image forming apparatus with less unevenness in brightness, uniform brightness and excellent operation stability.

[Brief description of drawings]

FIG. 1 is a schematic plan view and a sectional view showing a configuration of a surface conduction electron-emitting device to which the present invention is applied.

FIG. 2 is a diagram showing activation time dependence of an emission current of a surface conduction electron-emitting device.

FIG. 3 is a schematic diagram showing an example of a voltage waveform used in an energization forming process that can be adopted when manufacturing a surface conduction electron-emitting device to which the present invention is applied.

FIG. 4 is a schematic diagram showing an example of a vacuum processing apparatus having a measurement / evaluation function.

FIG. 5 is a graph showing an example of a relationship between an emission current Ie, a device current If, and a device voltage Vf for a surface conduction electron-emitting device to which the present invention is applied.

FIG. 6 is a schematic view showing an example of a ladder-shaped electron source to which the present invention is applied.

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

FIG. 8 is a schematic diagram showing an example of a display panel of an image forming apparatus to which the present invention has been applied.

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

FIG. 10 is a block diagram showing an example of a drive circuit for displaying an image according to an NTSC television signal on the image forming apparatus.

FIG. 11 is a schematic view showing a manufacturing process of a surface conduction electron-emitting device to which the present invention is applied.

FIG. 12 is a diagram showing activation time dependency of emission current of the surface conduction electron-emitting device of Example 1.

FIG. 13 is an explanatory diagram of an electron source manufacturing process of Example 4.

FIG. 14 is a schematic diagram showing a structure of a conventional surface conduction electron-emitting device.

[Explanation of symbols]

1: substrate, 2: activation suppressing layer, 3: activation promoting layer, 4,
5: device electrode, 6: conductive thin film, 7: electron emission part, 1
0: Substrate with activation suppressing layer and activation promoting layer, 40:
Device current If flowing through the conductive thin film 6 between the device electrodes 4 and 5
Ammeter for measuring the voltage, 41: Power supply for applying the element voltage Vf to the electron emitting element, 42: Ammeter for measuring the emission current Ie emitted from the electron emitting portion 5 of the element, 43: Anode High-voltage power supply for applying voltage to the electrode 44, 44: Anode electrode for capturing emission current Ie emitted from the electron emission portion of the device, 45: Vacuum device, 46: Exhaust pump, 71: Electron source substrate, 72: X-direction wiring, 73: Y-direction wiring, 74: Surface conduction electron-emitting device, 75: Connection, 81: Rear plate, 82: Support frame, 83: Glass substrate, 84: Fluorescent film, 85: Metal back, 86: Face plate, 87: High voltage terminal, 8
8: envelope, 91: black conductive material, 92: phosphor, 10
1: display panel, 102: scanning circuit, 103: control circuit, 104: shift register, 105: line memory,
106: synchronization signal separation circuit, 107: modulation signal generator,
Vx and Va: DC voltage source, 121: interlayer insulating film, 1
22: Contact hole, 123: Conductive thin film, 12
4: Cr film

Claims (10)

[Claims] 1. An electron-emitting device having a pair of device electrodes provided to face each other on an insulating substrate, and a conductive thin film having an electron-emitting portion provided between the device electrodes, wherein An electron-emitting device, wherein the insulating substrate has an activation suppressing layer and an activation promoting layer formed on the layer. 2. The electron-emitting device according to claim 1, wherein the activation suppressing layer is a good heat conductive insulator. 3. The activation suppressing layer is a layer containing any one of aluminum oxide, tantalum oxide, titanium oxide, silicon nitride, and aluminum nitride as the good thermal conductive insulator. The electron-emitting device according to claim 2. 4. The electron-emitting device according to claim 1, wherein the activation promoting layer is glass containing SiO ₂ . 5. The insulating substrate is formed by sequentially laminating an activation suppressing layer made of a good thermal conductive insulator and an activation promoting layer having lower thermal conductivity than the layer on a base. The electron-emitting device according to claim 1, wherein 6. The electron-emitting device according to claim 1, wherein the conductive thin film is a fine particle aggregate. 7. The electron-emitting device according to claim 1, wherein the electron-emitting device is a surface conduction electron-emitting device. 8. A device array comprising a plurality of electron-emitting devices according to claim 1 arranged in parallel and connected.
An electron source, which has at least one column and in which wirings for driving each element are arranged in a ladder shape. 9. A plurality of electron-emitting devices according to any one of claims 1 to 7 are arranged in a matrix in the X and Y directions,
One of the electrodes of the electron-emitting devices arranged in the same row is commonly connected to the wiring in the X direction, and the other of the electrodes of the electron-emitting devices arranged in the same column is in the Y direction. An electron source that is commonly connected to wiring. 10. An image forming apparatus, wherein the electron source according to claim 8 and an image forming member are arranged to face each other, and an image is formed based on an input signal.