JP2000090819A - Electron emitting element, electron source, image forming device, and manufacture of electron emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron emitting characteristic equal to that to be obtained in an activating process and capable of preventing the unevenness of emission between elements by forming a film of the organic material on a board, and providing a conductive thin film and electrodes for applying the voltage to the conductive thin film on the organic material film, and thereafter, forming the conductive thin film with an electron emitting part. SOLUTION: An organic material film 6 is formed on a board 1. As a material for the organic material film 6, thermosetting resin is desirable, and furfuryl alcohol, furan resin, phenol resin, polyimide resin or the like is used. In this case, polyimide resin is desirable on points of film forming property and heat resistance. In the activating process, a processing for controlling and leading the gas at the optimal gas pressure is eliminated, and the organic material film 6 is provided between a conductive thin film 4 as an electron emitting part 5, electrodes 2, 3 for applying voltage and the board 1 so as to improve the electron emitting characteristic. Namely, a stabilized characteristic capable of preventing the leakage of the element current and restricting the unevenness can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electron-emitting device, an electron source having a plurality of the electron-emitting devices, an image forming apparatus having the electron source, and a method of manufacturing the electron-emitting device.

[0002]

2. Description of the Related Art Conventionally, two types of electron emitting devices, a thermionic electron source and a cold cathode electron source, are known. Field emission type (hereinafter referred to as FE type) cold metal electron sources, metal / insulating layer /
There are a metal type (hereinafter, referred to as an MIM type) and a surface conduction electron-emitting device.

[0003] As an example of the FE type, a report by Dyke et al.
(WPDyke and WWDolan. “Field emission”, Advavce
in Electron Physics, 8, 89 (1956)), Spin
dt report (CASpindt, “Physical Properties of thin-f
ilm field emission cathodes with molybdenium cone
s ", J. Appl. Phys., 47, 5248 (1976)).

As an example of the MIM type, a report by Mead (CAM
ead, J. Appl. Phys., 32, 646 (1961)) are known.

As an example of a surface conduction electron-emitting device, a report by Elinson (MI Elinson RadioEng. Electron Phy
s., 10 (1965)).

[0006] The surface conduction electron-emitting device utilizes the phenomenon that electron emission occurs when a current flows through a small-area thin film formed on a substrate in parallel with the film surface. As the surface conduction electron-emitting device, those using the SnO ₂ thin film described in the above-mentioned report of Elinson, those using the Au thin film (G. Dittmer, Thin Solid Films, 9,317 (1972)),
In ₂ O ₃ / Sn ₂ O thin film (M. Hartwell and
CGFonstad, IEEE Trans. ED Conf., 519 (1975)), using a carbon thin film (Araki et al., Vacuum, Vol. 26, No. 1,
22 (1983)) and the like.

FIG. 9 shows a configuration of the above-mentioned Hartwell device as a typical device configuration of these surface conduction electron-emitting devices. In FIG. 1, reference numeral 1 denotes a substrate.
Reference numeral 4 denotes a conductive thin film, which is formed of a metal oxide thin film or the like formed by sputtering in an H-shaped pattern, and the electron emitting portion 5 is formed by an energization process called energization forming described later. The distance L between device electrodes in the figure is 0.5 mm to 1 m.
m and W 'are set at 0.1 mm. Since the position and shape of the electron-emitting portion 5 are unknown, they are shown as a schematic diagram.

Conventionally, in these surface conduction electron-emitting devices, the electron-emitting portion 5 is subjected to an energization process called energization forming in advance 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. And forming the electron-emitting portion 5 in an electrically high-resistance state.

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 process is configured to apply a voltage to the conductive thin film 4 and cause a current to flow through the device, thereby causing the electron-emitting portion 5 to emit electrons.

The above-mentioned surface conduction electron-emitting device has an advantage that a large number of devices can be arranged in a large area because of its simple structure and easy manufacture. Therefore, various applications that make use of the characteristics are being studied. For example,
Display devices such as a charged beam source and an image display device are exemplified.

[0011]

SUMMARY OF THE INVENTION In the above-mentioned surface-conduction electron-emitting device, the present invention has good and stable device characteristics by improving the manufacturing process and device structure of the surface-conduction electron-emitting device. A method of making a surface conduction electron-emitting device was proposed.

In a conventional method of manufacturing a surface conduction electron-emitting device, a device formed with a pair of electrodes and a conductive thin film is placed in a vacuum atmosphere, subjected to a forming step, and then subjected to a vacuum atmosphere. Then, a gas having at least one kind of element common to the new deposit is introduced into the electron-emitting portion, and a pulse voltage appropriately selected for several minutes to several tens minutes is applied (activation step). This was effective in improving the characteristics of the device. In this step, the characteristics of the electron-emitting device, that is, the electron emission current Ie, are significantly increased and improved with respect to the voltage while maintaining the threshold value.

However, the above-mentioned activation step has the following problems.

Problems 1. In the introduction of the gas accompanying the activation, it is necessary to introduce the gas at an optimum gas pressure. Particularly, depending on the introduced gas, the pressure is low or there is a problem of control. In addition, when the pressure is approximately the same as that in a vacuum atmosphere, the time required for the activation step may fluctuate due to water, oxygen, and the like remaining in the vacuum atmosphere, and the properties of the substances deposited on the electron-emitting portion may be different. Was. This has caused a characteristic variation in an electron source in which a plurality of electron-emitting devices are arranged or in an image forming apparatus.

Problem 2. Conventionally, in an image forming apparatus, an electron source substrate on which a plurality of pairs of electrodes, a conductive thin film and wirings for connecting to the pair of electrodes are formed, and a face plate made of a phosphor or the like are bonded at a high temperature, and a vacuum After forming an enclosure (referred to as a sealing step), a voltage is applied from the wiring to perform steps such as a forming step and an activation step.
The electron emission characteristics and image characteristics were inspected, and the vacuum envelope was sealed. In these series of steps, since the above-mentioned sealing step is performed after assembling the image forming apparatus, if a defect occurs in the electron source substrate for some reason, the entire image forming apparatus itself must be defective. Therefore, the image forming apparatus is expensive. For this reason, it has been desired to manufacture an image forming apparatus by performing a forming and activating process on the electron source substrate, assembling the electron source substrate which is a good product after inspection, and the face plate.

An object of the present invention is to provide a method for manufacturing an electron-emitting device having an electron-emitting characteristic that is equal to or more than that obtained by an activation step and does not vary among devices.

It is another object of the present invention to provide a method for manufacturing an electron-emitting device which can perform a sealing step of an envelope of an image forming apparatus after forming.

[0018]

The present invention for achieving the above-mentioned object has the following constitution.

Conventionally, in the activation step, it has been necessary to control and introduce a gas at an optimum gas pressure. However, the inventor of the present invention has omitted the activation step which has been effective in the conventional device by manufacturing the electron-emitting device according to the present invention, that is, by providing the organic material film under the conductive thin film and the electrode. Further, it has been found that characteristics equal to or higher than the electron emission characteristics of the conventional device can be obtained. According to this manufacturing method, the pressure control of the introduced gas in the activation step, the influence of the gas remaining in the vacuum atmosphere, and the like, which are conventionally required for the element, are reduced, and stable element characteristics can be obtained.

Further, the present invention has a process of manufacturing an electron source substrate and its inspection, a process of manufacturing a face plate, and an inspection thereof, and a process of assembling a vacuum envelope with a face plate having an electron source substrate and an image forming member. According to the method of manufacturing an image forming apparatus, the image forming apparatus can be manufactured at a low cost because the post-process assembly can be performed using only non-defective products in which the electron source and the face plate have been inspected.

Further, since intermediate products generated in the activation step have been removed from the electron source substrate in advance, water, water, and the like are used in the step of sealing and assembling the electron source substrate, the face plate having the phosphor, and the like. Since mainly removal of oxygen and the like is performed, a stable image forming apparatus can be easily manufactured.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a conventional electron-emitting device and an electron-emitting device according to the present invention will be described in detail with reference to the drawings.

FIG. 2 is a schematic view showing one example of a method for manufacturing a conventional electron-emitting device and the electron-emitting device of the present invention.

First, a conventional method for manufacturing an electron-emitting device will be described in detail. As the drawing of the conventional device, the drawing of the Hartwell device of FIG. 9 described above is used. In FIG. 9, 1 is a substrate, 2 and 3 are device electrodes, 4 is a conductive thin film, and 5 is an electron emitting portion. Organic material film 6 in FIG.
Are characteristic constituent members of the present invention.

In the conventional device fabrication, first, device electrodes 2 and 3 are formed on a substrate 1 at a distance of L. Next, droplets composed of a solution containing a metal element are discharged from a droplet applying device (inkjet recording device), and the conductive thin film 4 is formed so as to be in contact with the device electrodes 2 and 3. next,
I. The substrate is heated by a heating device in a vacuum described below to reduce the thin film portion of the conductive thin film 4, for example, by a forming process described later to cause a crack in the conductive thin film,
An electron emitting portion 5 is formed.

II. A crack is generated in the conductive thin film by a forming process described later, an electron emission portion 5 is formed, and the substrate is heated by a heating device in a reducing atmosphere to aggregate the thin portion of the conductive thin film.

As a specific example of the droplet applying device, any device can be used as long as it can form an arbitrary droplet, but in particular, a range of about several tens to several tens of ng. It is preferable to use an ink-jet type device which can be controlled by the above method and can easily form a small amount of droplets of several ng to several tens ng.

The ink-jet type apparatus employs an ink-jet ejecting apparatus using a piezoelectric element or the like, and a method of forming bubbles in a liquid by thermal energy and discharging the liquid as droplets (hereinafter, referred to as a bubble jet method). An ink jet injection device and the like can be mentioned.

The conductive thin film 4 is particularly preferably a fine particle film composed of fine particles in order to obtain good electron emission characteristics.
It is appropriately set depending on the resistance value between the element electrodes 2 and 3 and the energization forming conditions described later, and is preferably several n.
m to several hundred nm, particularly preferably 1 nm to 50 nm.

The sheet resistance value is 10 ³ to 10 ⁷ Ω /
□.

The material constituting the conductive thin film 4 is Pd, P
t, Ru, Ag, Au, Ti, In, Cu, Cr, F
e, metal such as Zn, Sn, Ta, W, Pb, PdO, S
Oxides such as nO ₂ , In ₂ O ₃ , and Sb ₂ O ₃ are exemplified.

The fine particle film described here is a film in which a plurality of fine particles are gathered, and has a fine structure not only in a state where the fine particles are individually dispersed and arranged, but also in a state where the fine particles are adjacent to each other or overlap each other (an island). The particle diameter of the fine particles is several nm to several hundred nm, preferably 1 nm to 20 nm.

Examples of the solution on which the droplets are based include a solution in which the above-described structural material of the conductive thin film 4 is dissolved in water, a solvent, or the like, and an organometallic solution. It is necessary.

As a material of the device electrodes 2 and 3, a general conductive material is used, for example, Ni, Cr, Au,
Metals or alloys such as Mo, W, Pt, Ti, Al, Cu, Pd, and Pd, Ag, Au, Ru, O ₂ , P
It is appropriately selected from a printed conductor composed of a metal such as d-Ag or a metal oxide and glass, a transparent conductor such as In ₂ O ₃ —SnO ₂ and a semiconductor material such as polysilicon.

The element electrode interval L is preferably several tens nm to
It is several hundred μm. Further, it is desirable that the voltage applied between the device electrodes is low, and it is required to manufacture the device with good reproducibility. Therefore, the preferable device electrode interval is several μm to several tens μm.

The element electrode length W 'is several μm to several hundred μm from the viewpoint of the resistance value of the electrode and the electron emission characteristics, and the film thickness d of the element electrodes 2 and 3 is several tens nm to several μm. Is preferred.

The electron-emitting portion 5 is a high-resistance crack formed in a part of the conductive thin film 4 and is formed by energization forming or the like. In addition, conductive fine particles having a particle size of several nm to several tens nm may be included in the crack. The conductive fine particles contain at least a part of the elements constituting the conductive thin film 4. Further, the electron emitting portion 5 and the conductive thin film 4 in the vicinity thereof may include carbon and a carbon compound.

The electron emitting portion 5 is formed by performing an energization process called energization forming of the element on which the conductive thin film 4 and the element electrodes 2 and 3 are formed. In the energization forming, an electric current is applied between the element electrodes 2 and 3 by a power supply (not shown) to locally destroy, deform or alter the conductive thin film 4, thereby forming a portion having a changed structure. The site where the structure is locally changed is referred to as an electron emitting portion 5. FIG. 3 shows an example of the voltage waveform of the energization forming.

The voltage waveform is particularly preferably in a pulse shape. A voltage pulse having a constant pulse peak value is continuously applied (FIG. 3A), and a voltage pulse is applied while increasing the pulse peak value ( FIG. 3B). First,
The case where the pulse crest value is a constant voltage (FIG. 3A) will be described.

In FIG. 3, T1 and T2 are the pulse width and pulse interval of the voltage waveform, and T1 is 1 μsec to 10 m.
The second and T2 are set to 10 μsec to 100 msec, and the peak value of the triangular wave (peak voltage of the energization forming) is appropriately selected according to the form of the surface conduction electron-emitting device, and an appropriate pressure, for example, 1 × 10 ⁻⁷ Pa It is applied for several seconds to several tens of minutes under an atmosphere of a moderate pressure. Note that the waveform applied between the electrodes of the element need not be limited to a triangular wave, and a desired waveform such as a rectangular wave may be used.

T1 and T2 in FIG. 3 (b) are the same as those in FIG. 3 (a), and the peak value of the triangular wave (the peak voltage of the energization forming) is increased by, for example, about 0.1 V / step, and the Apply under a vacuum atmosphere.

In the energization forming process in this case, during the pulse interval T2, a voltage that does not locally destroy or deform the conductive thin film 4 is applied, the current is measured and detected, and the energization forming is terminated. .

The above forming step and the subsequent steps are performed in a measurement and evaluation system as shown in FIG. This measurement evaluation system will be described.

In FIG. 4, the same reference numerals as those in FIG. 9 denote the same members. Reference numeral 71 denotes a power supply for applying a device voltage Vf to the device; 70, an ammeter for measuring a device current If flowing through the conductive thin film 4 between the device electrodes 2 and 3; An anode electrode for capturing the emission current Ie to be emitted; 73, a high-voltage power supply for applying a voltage to the anode electrode 74; 72, an ammeter for measuring the emission current Ie emitted from the electron emission section 5; Is a vacuum device, and 76 is an exhaust pump.

The electron-emitting device, the anode electrode 74 and the like are installed in a vacuum device 75. The vacuum device 75 is provided with necessary equipment such as a vacuum gauge (not shown) and operates under a desired pressure. Can be measured and evaluated. Further, the entire vacuum device 75 and the substrate 1 of the electron-emitting device are provided.
Can be heated by a heater.

Next, a conventional activation step will be described.

Next, it is desirable to perform a process called an activation process on the device on which the energization forming has been completed.

The activation step is, for example, 10 ^-6 to 10 ^-7
This is a process of repeatedly applying a voltage pulse having a constant pulse peak value at a pressure of about Pa, similar to the energization forming, and deposits carbon and a carbon compound caused by an organic substance existing in a vacuum atmosphere on a conductive thin film. This is a process for significantly changing the device current If and the emission current Ie. The activation process ends while measuring the device current If and the emission current Ie, for example, when the emission current Ie is saturated.
Further, it is preferable that the voltage pulse to be applied is performed by an operation drive voltage.

Here, carbon and carbon compound are defined as
It is graphite (refers to both single crystal and polycrystal) and amorphous carbon (refers to a mixture of amorphous carbon and polycrystal graphite), and its film thickness is preferably 50 nm or less, more preferably 30 nm or less.

The above is the description of the activation step according to the conventional example.

The electron-emitting device thus manufactured is preferably operated and driven in an atmosphere at a pressure lower than the pressure in the energization forming step and the activation step. Also,
It is desirable to drive the device after heating at 80 ° C. to 150 ° C. in a lower pressure atmosphere.

The atmosphere under a pressure lower than the pressure in the energization forming step and the activation step is, for example, about 1
It is under a pressure of 0 ^-7 Pa or more, more preferably an ultrahigh vacuum system, under a pressure at which carbon and carbon compounds hardly newly deposit on the conductive thin film. This makes it possible to stabilize the device current If and the emission current Ie.

The basic characteristics of the surface conduction electron-emitting device thus manufactured will be described below.

The basic characteristics of the surface conduction electron-emitting device described below are as follows. In the measurement and evaluation system shown in FIG. 4, the voltage of the anode electrode 74 is 1 kV to 10 kV, and the distance H between the anode electrode 74 and the surface conduction electron-emitting device is 2 ８8 mm based on measurements made.

Next, FIG. 5 shows a typical example of the relationship between the device current If and the emission current Ie and the device voltage Vf.
In the figure, the emission current Ie is shown in arbitrary units because it is much smaller than the device current If.

As is clear from FIG. 5, the surface conduction electron-emitting device suddenly receives a device current If () when a device voltage Vf exceeding a certain voltage (referred to as “threshold voltage”; Vth in FIG. 5) is applied. The emission current Ie (thick solid line in FIG. 5) rapidly increases in the same manner. On the other hand, below the threshold voltage Vth, the element current If and the emission current Ie are hardly detected. That is, the element current I
fth and clear threshold voltage Vth for emission current Ie
Is a non-linear element having

In the surface conduction type electron-emitting device having the conductive thin film remaining in the electron-emitting portion of the conductive thin film 4, the device current If (thin solid line in FIG. 5) is detected below the threshold voltage Vth. , An invalid element current If (hereinafter referred to as a leak current) flows. The generation of the leak current is caused by the device electrodes 2, 3
And the effective value of the device voltage Vf applied to the electron-emitting portion 5 is significantly reduced, and as a result, the characteristics of the emission current Ie are also reduced.

The remaining portion of the conductive thin film 4 varies depending on the applied voltage value of the energizing process, the conductivity of the conductive thin film 4, the thickness of the conductive thin film 4, and the like. As a result, it has been clarified that the conductive thin film 4 having a thickness of 25% or less of the thickest thickness of the conductive thin film 4 may be formed as a residue of the conductive thin film 4 as a residue of the energization processing.

Next, features of the device according to the present invention and a method of manufacturing the same will be described.

In the conventional example, optimization of the gas pressure at the time of introduction of the gas accompanying the activation, fluctuation of the activation process time due to the influence of water, oxygen, etc., at the same pressure as in a vacuum atmosphere, electron emission There was a problem such as property variation of the material deposited in the part. However, according to the present invention, the use of a moldable organic material instead of a gas and the provision of the element electrode and the conductive film serving as the electron-emitting portion under the conductive film facilitates an increase in the area and a variation in characteristics. . Also, by using a printing method, a spin coating method, or the like for the base film made of the organic material, the process can be simplified and the yield can be improved.

In a conventional example, an image forming apparatus conventionally includes an electron source substrate on which a plurality of pairs of electrodes, a conductive thin film, wirings and the like connected to the pair of electrodes are formed, a phosphor and the like. After bonding with the face plate at high temperature to form a vacuum envelope (referred to as a sealing process), a voltage is applied from the wiring, and a process such as a forming process and an activation process is performed. Was inspected and the vacuum envelope was sealed. In these series of steps,
Since the above-described sealing step is performed after assembling the image forming apparatus, if a defect occurs in the electron source substrate for any reason, the entire image forming apparatus itself must be a defective product. Had to be expensive. However, according to the present invention, in the electron source substrate,
Since it is possible to inspect the element characteristics of the electron-emitting device and then assemble only a good product with the face plate to manufacture an image forming apparatus, the yield can be improved and the image forming apparatus can be made inexpensive.

Hereinafter, the fabrication of the device according to the present invention will be described in detail.

FIG. 1 is a view showing one example of a surface conduction electron-emitting device manufactured by the manufacturing method of the present invention. FIG.
In the drawings, 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 organic material film, which is a characteristic constituent member of the present invention.

First, an organic material film 6 (FIG. 1), which is a characteristic step of the present invention, is formed on the substrate 1 in forming the device. As a material of the organic material film 6, a thermosetting resin is preferable, and examples thereof include furfuryl alcohol, a furan resin, a phenol resin, and a polyamide resin. From the viewpoint of film forming properties and heat resistance, a polyimide resin is more preferable. Is suitable. Therefore, in the activation step shown in the above conventional example,
It was necessary to control and introduce gas with the optimal gas pressure,
According to the present invention, by providing an organic material film between a conductive film serving as an electron emission portion and an electrode for applying a voltage, and a substrate, it is possible to obtain electron emission characteristics equal to or higher than conventional ones. Become.

As the film forming method, there are various types, and it is not particularly limited. However, from the viewpoints of production stability, cost, and the like, more preferable is a film forming method by a printing method and a spin coating method. .

On the organic material film thus formed, an element electrode 2 was formed.
And 3 are formed at a distance of L. The subsequent steps are the same as in the conventional example up to the formation (forming) of the electron-emitting portion. Then placed in a vacuum processing apparatus shown substrate that ended up forming step in FIG. 4, 10 ^-6 to 1
Under a pressure of about 0 ^-7 Pa, a voltage pulse is repeatedly applied while increasing the voltage pulse, and the cracks formed in the conductive thin film are further deepened into the organic material film to significantly increase the element current If and the emission current Ie. Change. This step is completed, for example, when the emission current Ie is saturated, while measuring the device current If and the emission current Ie, as in the case of the activation in the conventional example.

The forming step can be regarded as a step of supplying electric energy or thermal energy or both to the organic material film.

The cell thus prepared is subjected to the same processing as in the above-mentioned conventional example, and the characteristics of the device current If, emission current Ie, etc. are evaluated.

[0069]

The present invention will be described in more detail with reference to the following examples.

[Embodiment 1] The structure of a surface conduction electron-emitting device according to this embodiment is the same as that shown in FIG. 1A is a plan view, and FIG. 1B is a schematic sectional view.

Hereinafter, a method for manufacturing the surface conduction electron-emitting device according to the present embodiment will be described in detail.

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 organic material thin film.

FIG. 2 is a diagram showing the manufacturing steps of the example and the comparative example. Hereinafter, the present invention will be specifically described with reference to FIG. 2 showing a procedure of a manufacturing method.

A surface conduction electron-emitting device as Comparative Example 1 was also prepared.

The substrate on which the surface conduction electron-emitting device of the present invention is formed is referred to as an A substrate, and the substrate on which the surface conduction electron-emitting device of the comparative example is formed is referred to as a B substrate.

It should be noted that an element having the same shape is provided on the substrate.
Individually formed.

First, the steps of the substrate A of the present invention will be described.

(Step 1): (Step of coating organic material film) An organic material film 6 (FIG. 1), which is a characteristic step of the present invention, is formed. After using a quartz substrate as the substrate 1 and washing it sufficiently with an organic solvent, a polyamic acid synthesized from a polymerization reaction of pyromellitic anhydride and bis (4-aminophenyl) ether is placed on the substrate 1. The polyimide film was applied by spin coating and baked at 350 ° C. to form a polyimide film having a thickness of 50 nm.

[0079]

Embedded image (Step 2): (Element electrode forming step) Next, this substrate is
t is used as a device electrode material, and the device electrodes 2 and 3 are formed by a sputtering method.
On each, 30 nm was deposited.

(Step 3): (Conductive thin film forming step) The device electrodes 2 and 3 formed on the polyimide film 6 on the substrate 1
Between the organic palladium solution (CCP423 manufactured by Okuno Pharmaceutical Co., Ltd.)
0) was formed by applying a solution for forming the conductive thin film 4 between the element electrodes 2 and 3 in the form of liquid droplets using an ink jet ejecting apparatus using a piezoelectric element as a liquid droplet applying apparatus.

Thereafter, the organometallic film was heated at 350 ° C. for 30 minutes.
Heat treatment was performed in the air for minutes. Note that the fine particle film described here is a film in which a plurality of fine particles are aggregated as described above, and has a fine structure not only in a state where the fine particles are individually dispersed and arranged, but also in a state where the fine particles are adjacent to each other or overlap each other. (Island-shaped) film. At this time, the conductive thin film 4
Has a trapezoidal shape with a thickness of 20 nm, and is thicker at the center and gradually thinner toward the periphery.

(Step 4): (Forming Step)
The substrate A was placed in the vacuum processing apparatus shown in FIG.
Under an atmosphere of a pressure of 10 ^-5 Pa) at 140 ° C.
After reducing the conductive thin film, a pulse-like voltage having a pulse width of 1 ms and a pulse interval of 10 ms is applied between the device electrodes 2 and 3 while gradually increasing the pulse peak value, and an energization process called forming is performed. went.

FIG. 4 is a schematic view showing a vacuum processing apparatus, which also has a function as a measurement and evaluation apparatus.

According to the above-described manufacturing method, ten surface conduction electron-emitting devices were prepared and measured by the measurement and evaluation apparatus shown in FIG. 4. As a result, in all the surface conduction electron-emitting devices, the device current If was measured. , And the device current If is 1.6 mA ± 5% in all the devices.
The emission current Ie was 1.45 μA ± 5%, and a surface conduction electron-emitting device having good device characteristics was obtained.

Example 2 Example 1 was repeated except that the polyimide used in Example 1 was replaced with a polyamic acid synthesized from a polymerization reaction of pyromellitic anhydride and p-phenylenediamine shown in the following figure. Similarly, an electron-emitting device was prepared and its characteristics were evaluated.

[0086]

Embedded image As a result, in all the surface conduction electron-emitting devices, there is no leakage current of the device current If, and in all the devices, the device current If is 1.3 mA ± 5% and the emission current Ie
Was 1.25 μA ± 5%, and a surface conduction electron-emitting device having good device characteristics was obtained.

[Comparative Example 1] Next, the steps of substrate B of the present invention will be described.

(Step 1): (Substrate Cleaning Step) A quartz substrate was used as the substrate 1, and this was sufficiently cleaned with an organic solvent.

(Step 2): (Element electrode forming step) Substrate A
Same as step.

(Step 3): (Step of Forming Conductive Thin Film) Same as the step of substrate A.

(Step 4): (Forming Step) Substrate A
Same as step.

(Step 5): (Activation step) Acetone is added to 1
After introducing into the vacuum processing apparatus of FIG. 4 at a pressure of 0 ^-2 Pa, the driving voltage is 15 V, the pulse width is 1 msec, and the pulse interval is 10 msec.
Was applied for 20 minutes.

Next, the vacuum processing apparatus shown in FIG. 4 was evacuated to 10 ⁻⁶ Pa, the substrate B was heated at 230 ° C. for 15 hours, and then returned to room temperature. A device was created.

According to the above-described manufacturing method, 10 surface-conduction electron-emitting devices on the substrate B were measured by the measurement and evaluation apparatus shown in FIG. 4, and it was found that the device current If leaked from the four devices. I understood. The remaining four element currents If
Is 1.5 mA ± 20%, and the emission current Ie is 1.02 μA ±
At 20%, the device characteristics lacked stability.

[Application Example 1] FIG. 6 shows an application example of an image forming apparatus in which element electrodes are arranged in a matrix using the surface conduction electron-emitting device manufactured in Example 1 of the present invention.

In FIG. 6, reference numeral 111 denotes an electron source substrate;
2 is an X-direction wiring, 113 is a Y-direction wiring, 152 is an X-direction wiring scanning circuit, and 153 is a Y-direction wiring control circuit.

Reference numeral 110 denotes a surface conduction electron-emitting device.
145 is a rear plate to which the electron source substrate 111 is fixed,
Reference numeral 144 denotes a face plate in which a fluorescent film 148 and a metal back 149 are formed on the inner surface of a glass substrate 147;
Reference numeral 6 denotes a support frame, and these members constitute an envelope.

The m X-direction wirings 112 are Dx1, Dx
2,..., Dxm, and can be made of a conductive metal or the like formed by a vacuum deposition method, a printing method, a sputtering method, or the like. The material, thickness, and width of the wiring are appropriately designed.
The Y-direction wiring 113 is formed of n of Dy1, Dy2,.
It is formed in the same manner as the X-direction wiring 112. An interlayer insulating layer (not shown) is provided between the m X-directional wirings 112 and the n Y-directional wirings 113 to electrically separate them (m and n are both common). Positive integer).

The interlayer insulating layer (not shown) is made of SiO ₂ or the like formed by a vacuum deposition method, a printing method, a sputtering method, or the like. For example, the substrate 11 on which the X-direction wiring 112 is formed
1 is formed in a desired shape on the entire surface or a part thereof. In particular, the film thickness, material, and manufacturing method are appropriately set so as to withstand the potential difference at the intersection of the X-direction wiring 112 and the Y-direction wiring 113.
The X-direction wiring 112 and the Y-direction wiring 113 are respectively drawn out as external terminals.

A pair of electrodes (not shown) constituting the surface conduction electron-emitting device 110 are electrically connected to m X-directional wires 112 and n Y-directional wires 113 by a connection made of a conductive metal or the like. ing.

The X-directional wiring 112 is connected to an X-directional wiring scanning circuit 152 for applying a scanning signal for selecting a row of the surface conduction electron-emitting devices 110 arranged in the X-direction. On the other hand, a modulation signal generator 157 for modulating each column of the surface conduction electron-emitting devices 110 arranged in the Y direction according to an input signal is connected to the Y-direction wiring 113. 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.

FIG. 7 is a schematic diagram showing the fluorescent film 148. The fluorescent film 148 can be composed of only a phosphor in the case of monochrome. In the case of color fluorescent film,
Depending on the arrangement of the phosphor, a black conductive material 91 called a black stripe or a black matrix or the like and the phosphor 9
2 can be configured. Black stripe,
The purpose of providing a black matrix is to make the color mixture and the like inconspicuous by making the painted portions between the phosphors 92 of the necessary three primary color phosphors black in the case of color display,
The object is to suppress a decrease in contrast due to reflection of external light on the fluorescent film 84. 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 147 can employ a precipitation method, a printing method, or the like irrespective of monochrome or color. Usually, a metal back 149 is provided on the inner surface side of the fluorescent film 148. The purpose of providing the metal back is to improve the brightness by mirror-reflecting the light toward the inner surface side of the emission of the phosphor toward the face plate 144 side, to act as an electrode for applying an electron beam acceleration voltage, The purpose is to protect the phosphor from damage due to collision of negative ions generated in the envelope. The metal back 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 144 may be provided with a transparent electrode (not shown) on the outer surface side of the fluorescent film 148 in order to further enhance the conductivity of the fluorescent film 148.

When performing the above-mentioned sealing, in the case of color, it is necessary to make each color phosphor correspond to the electron-emitting device.
Sufficient alignment is essential.

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. . FIG. 8 is a block diagram of a drive circuit for causing the image forming apparatus in FIG. 6 to display an image based on an NTSC signal. In FIG.
151 is an image display panel, 152 is a scanning circuit, 153 is a control circuit, and 154 is a shift register. 155 is a line memory, 156 is a synchronizing signal separation circuit, 157 is a modulation signal generator, and Vx and Va are DC voltage sources.

The display panel 151 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 the output electron beam of each element of one row of the 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 kV from a DC voltage source Va, which applies sufficient energy to an electron beam emitted from the surface conduction electron-emitting device to excite the phosphor. Is the accelerating voltage for

Next, the scanning circuit 152 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
One of V (ground level) is selected, and is electrically connected to the terminals Dx1 to Dxm of the display panel 151. The switching elements S1 to Sm are connected to the control circuit 1
It operates based on the control signal T _SCAN output by 53 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 uses a driving voltage applied to an element that is not scanned based on the characteristics (electron emission threshold voltage) of the surface conduction type electron emission element. It is set to output a constant voltage that is equal to or lower than the voltage.

The control circuit 153 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 153 generates T _SCAN, T _SFT, and T _MRY control signals for each unit based on the synchronization signal T _SYNC sent from the synchronization signal separation circuit 156.

The synchronizing signal separating circuit 156 is a circuit for separating a synchronizing signal component and a luminance signal component from an NTSC television signal input from the outside. The synchronization signal separated by the synchronization signal separation circuit 156 is composed of a vertical synchronization signal and a horizontal synchronization signal.
_This is shown as a _SYNC signal. 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 154.

The shift register 154 converts the DATA signal input serially in time series into a serial / parallel format for each line of an image. The shift register 154 converts the DATA signal into a control signal T _SFT sent from the control circuit 153. (Ie, the control signal T _SFT is _supplied to the shift register 15
4 shift clocks. ). The data for one line of the serial / parallel-converted image (corresponding to the drive data for N electron-emitting devices) is Id1
The output from the shift register 154 is as N parallel signals of Idn to Idn.

The line memory 155 is a storage device for storing data for one line of an image for a necessary time only, and stores the contents of Id1 to Idn as appropriate according to a control signal T _MRY sent from the control circuit 153. The stored contents are output as I'd1 to I'dn and input to the modulation signal generator 157.

The modulation signal generator 157 outputs the 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 transmitted through the terminals Doy1 to Doyn to the surface conduction electron-emitting device in the display panel 151. 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. However, 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, 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 157. be able to.

When implementing the pulse width modulation method,
As the modulation signal generator 157, 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 154 and the line memory 15
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 separation circuit 156 into a digital signal. For this purpose, an A / D converter may be provided at the output section of the 156. In connection with this, the line memory 15
Depending on whether the output signal of 5 is a digital signal or an analog signal,
The circuit used for modulation signal generator 157 is slightly different. That is, in the case of a voltage modulation method using a digital signal, for example, a D / A conversion circuit is used as the modulation signal generator 157, and an amplification circuit and the like are added as necessary. In the case of the pulse width modulation method, the modulation signal generator 157 includes, for example, a high-speed oscillator, a counter for counting the number of waves output from the oscillator, and a comparator for comparing the output value of the counter with the output value of the memory. (Comparator) is used. If necessary, an amplifier for amplifying the 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, an amplification circuit using, for example, an operational amplifier can be used as the modulation signal generator 157, and a level shift circuit and the like can be added as necessary. In the case of the pulse width modulation method, for example, a voltage-controlled oscillation circuit (VOC) can be employed, and an amplifier for amplifying the voltage up to the drive voltage of the surface conduction electron-emitting device can be added as necessary.

In the image display apparatus 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 149 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 148 and emit light to form an image.

The configuration of the image forming apparatus described here is an example of the image forming apparatus, and various modifications can be made based on the technical idea of the present invention. For input signals, NTSC
Although the method has been described, the input signal is not limited to this, and a TV signal (for example, high-definition TV) comprising a larger number of scanning lines than the PAL, SECAM, or the like can be adopted.

The image forming apparatus described here is a display apparatus for a television broadcast, a display apparatus such as a video conference system or a computer, and an image forming apparatus as an optical printer using a photosensitive drum or the like. Etc. can also be used.

The image forming apparatus shown in FIG. 6 including the electron-emitting device 110 manufactured by the manufacturing method shown in the embodiment and the example of the present invention is displayed on the television display based on the NTSC television signal by the driving circuit shown in FIG. And showed good performance without any problem.

[0127]

As described above, according to the method for manufacturing an electron-emitting device of the present invention, an organic material is formed on a substrate,
A conductive thin film serving as an electron-emitting portion is provided on the organic material film, and an electrode for applying a voltage to the conductive thin film is provided. Thereafter, the electron-emitting portion is formed in the conductive thin film to reduce a device current. It is possible to obtain a surface conduction electron-emitting device having good characteristics without leakage current and stable characteristics with little variation.

[Brief description of the drawings]

FIG. 1 is a schematic plan view (a) and a schematic cross-sectional view (b) showing a configuration of a surface conduction electron-emitting device of the present invention.

FIGS. 2A and 2B are a manufacturing process diagram for an electron-emitting device of the present invention and a manufacturing process diagram for a conventional electron-emitting device, respectively.

FIG. 3 is a schematic diagram showing an example of a voltage waveform in energization forming at the time of manufacturing the electron-emitting device of the present invention.

FIG. 4 is a schematic configuration diagram of an example of a vacuum processing apparatus that also has a measurement evaluation device for measuring electron emission characteristics.

FIG. 5 is a diagram showing device current and emission current-device voltage characteristics (1-V characteristics) of a surface conduction electron-emitting device.

FIG. 6 is a partially cutaway perspective view showing an example of an image display device including an electron source having a surface conduction electron-emitting device of the present invention formed on a substrate.

FIG. 7 is a plan view showing a pattern example of a fluorescent film.

FIG. 8 is a schematic diagram illustrating an example of a drive circuit for performing display in an image forming apparatus according to an NTSC television signal.

FIG. 9 is a schematic diagram showing an example of a conventional surface conduction electron-emitting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2, 3 Element electrode 4 Conductive thin film 5 Electron emission part 6 Organic material film 70 Ammeter 71 Power supply 72 Ammeter 73 High voltage power supply 74 Anode electrode 75 Vacuum device 76 Exhaust pump 110 Surface conduction type electron emission element 111 Electron source substrate 112 X-direction wiring 113 Y-direction wiring 144 Face plate 145 Rear plate 146 Support frame 144, 145, 146 Outer peripheral 147 Glass substrate 148 Fluorescent film 149 Metal back 151 Display panel 152 Scanning circuit 153 Control circuit 154 Shift register 155 Line memory 156 Synchronization Signal separation circuit 157 Modulation signal generator Vx, Va DC voltage source

Claims (7)

[Claims] An organic material is formed on a substrate, a conductive thin film serving as an electron emitting portion is provided on the organic material film, and an electrode for applying a voltage to the conductive film is provided. A method for manufacturing an electron-emitting device, comprising: forming an electron-emitting portion on a conductive thin film. 2. The method according to claim 1, wherein the organic material is a thermosetting resin. 3. The method according to claim 1, wherein the organic material is a thermosetting polyimide resin. 4. The method according to claim 1, further comprising the step of supplying electric energy, thermal energy, or both to the organic material.
13. The method for manufacturing an electron-emitting device according to item 10. 5. An electron-emitting device manufactured by the manufacturing method according to claim 1. 6. An electron source comprising a plurality of the electron-emitting devices according to claim 5. 7. An image forming apparatus comprising the electron source according to claim 6.