JPH09326241A - Image forming device and manufacture therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain degradation of an electron emitting characteristic, further improve its service life, and prevent a characteristic change by sealing gas of an organic substance having average staying time shorter than a driving period in a vessel of an image forming device. SOLUTION: An image forming device is arranged in a vacuum vessel 47 composed of a face plate 46, a support frame 42 and a rear plate 41. Electron emitting elements 34 are arranged in a plurality on a base board 31 fixed to the rear plate 41, and a fluorescent screen 44 and a metal back 45 or the like are formed on an inside surface of a glass substrate 43 of the face plate 46. The rear plate 41 and the face plate 46 are joined to the support frame 42 by using frit glass or the like having a low melting point. X directional wiring 32 and Y directional wiring 33 are connected to a pair of element electrodes of a surface transmission electron emitting element. Gas of an organic substance whose partial pressure is not less than 1×10<-6> Pa is sealed in the vacuum vessel 47, and its whole pressure is not more than 1×10<-3> Pa.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using an electron source in which electron-emitting devices are integrated and arranged.

[0002]

BACKGROUND ART A CRT has been widely used as an image forming apparatus that displays an image using an electron beam.
On the other hand, in recent years, flat panel display devices using liquid crystal have been
Although it has become widespread in place of RT, it is not self-luminous and therefore has a problem that it must have a backlight. Therefore, development of a self-luminous display device has been desired. As a self-luminous display device, a plasma display has recently been commercialized, but the principle of light emission is different from the conventional CRT, and it is said that it is slightly inferior to the CRT in terms of image contrast and good coloring. The current situation is that no If a plurality of electron-emitting devices are arranged to form an electron source and this electron source is used in a flat panel image forming apparatus, it is expected that light emission of the same quality as that of a CRT can be obtained, and many researches and developments have been conducted.

For example, the applicant has proposed several proposals regarding an electron source in which a large number of surface conduction electron-emitting devices, which are a kind of cold cathode electron-emitting devices, are arranged on a substrate, and an image forming apparatus using the same. Is going.

Conventionally, two types of electron-emitting devices have been known, which are roughly classified into a thermoelectron-emitting device and a cold cathode electron-emitting device. The cold cathode electron emission device includes a field emission type (hereinafter referred to as “FE type”), a metal / insulating layer / metal type (hereinafter referred to as “MIM type”), a surface conduction type electron emission device, and the like. As an example of FE type, WP Dyke & W.
W. Dolan, "Field emission", Advance in Electoron P
hysics, 8, 89 (1956), or CASpindt, "PHYSICAL
Properties of thin-film field emission cathodes w
ith molybdenium cones ", J. Appl. Phys., 47, 5248
(1976) and the like are known.

As an example of the MIM type, CA Mead,
"Operation of Tunnel-Emission Devices", J. Apply.
Phys., 32, 646 (1961) and the like are known.

Further, as an example of the surface conduction electron-emitting device type, MI Elinson, Recio Eng. Electron Phys., 10,
1290, (1965), etc.

Further, the surface conduction electron-emitting device utilizes a phenomenon in which electron emission occurs when a current is passed through a thin film having a small area formed on a substrate in parallel with the film surface. As the surface conduction electron-emitting device, one using a SnO ₂ thin film by Erinson et al., One using an Au thin film [G. Dittmer: "Thin Solid Films", 9, 317 (19
72], In ₂ O ₃ / SnO ₂ , by thin film [M. Hartwe
ll and CG Fonstad: "IEEE Trans. ED Conf." 519
(1975)], by a carbon thin film [Hiraki Araki et al .: Vacuum,
Vol. 26, No. 1, p. 22 (1983)] and the like are reported.

[0008]

The present applicant has reported an element having a structure as schematically shown in FIGS. 2A and 2B as a surface conduction electron-emitting device.
For example, in Japanese Patent Laid-Open No. 7-235255, the structure and manufacturing method of the surface conduction electron-emitting device and the image forming apparatus using the same are described in detail, and therefore will be briefly described below.

In FIGS. 2A and 2B, 1 is a substrate,
Reference numerals 2 and 3 are a pair of device electrodes, and 4 is a conductive film, and an electron emitting portion 5 is formed on a part thereof. As a method of forming the electron emitting portion 5, a voltage is applied between the pair of device electrodes 2 and 3 to deform, alter or destroy a part of the conductive film 4 to have high resistance. There is a method of performing the above, which is referred to as "energization forming process". In order to form the electron emitting portion 5 having good electron emitting characteristics by this method, it is preferable that the conductive film 4 is made of conductive fine particles. As the material, for example, P
Examples thereof include dO fine particles. The voltage applied in the energization forming process is preferably a pulse voltage, as shown in FIG.
Either a method of applying a pulse having a constant crest value as shown in FIG. 17A or a method of applying a pulse having a gradually increasing crest value as shown in FIG. 17B can be applied.

In addition, by a process called activation process,
It is also reported that a coating film containing carbon as a main component is deposited on the electron-emitting portion 5 and its vicinity, thereby increasing the electron emission amount. This treatment is performed by repeatedly and continuously applying an appropriate pulse voltage to the electron-emitting device described above in an atmosphere containing a gas of an organic substance.

The coating containing carbon as the main component is
For example, graphite (including so-called HOPG, PG, and GC, HOPG is a crystal structure of almost perfect graphite, PG is a crystal grain with a crystal grain size of about 20 nm and the crystal structure is somewhat disordered, and GC is a crystal grain with a crystal grain size of about 2 nm. It means that the structure is further disordered), amorphous carbon (amorphous carbon, and a mixture of amorphous carbon and fine crystals of graphite).

FIG. 2C is a schematic diagram showing the structure around the electron-emitting portion 5 more concretely. The method of depositing the coating differs depending on the method of applying the pulse voltage and the like. When the polarity of the pulse is only in one direction, the coating 6 containing carbon as the main component is mainly used as shown in the figure. The cracks (deformed and destroyed parts) formed by the forming process are deposited on the high potential side. In FIG. 2C, the element electrode 3 side is the high potential side. Electron emission occurs from the crack and its vicinity. Further, by performing the activation treatment while reversing the polarity of the pulse, it is possible to form the deposited film substantially evenly on both sides of the crack in the electron emitting portion.

Further, after this, it is desirable to perform a process called stabilization process. This is because the molecules of the organic substance used in the activation process are the substrate of the electron-emitting device,
In the process of removing what remains after being adsorbed on the inner wall of the vacuum container of the image forming apparatus, it is possible to prevent the above-mentioned carbon-based coating film from further depositing and stabilize the characteristics. is there. Specifically, for example, while heating the inside of the vacuum device in which the electron-emitting devices are arranged, exhaust is performed by an ultra-high vacuum exhaust device including, for example, a scroll pump and an ion pump. As a result, the organic substance is removed, and the deposition of the coating film containing carbon as a main component does not proceed, and as a result, the electron emission characteristics are stabilized.

As a problem when the stabilization process is not performed, the following points are mentioned in the application by the present applicant, Japanese Patent Application Laid-Open No. 7-235275. (1) When the electron-emitting device is left without being driven and then driven again, the electrical characteristic (current-voltage characteristic) of the electron-emitting device changes, and the emission current emitted from the device temporarily increases. (2) When the pulse width of the voltage applied to the element is changed,
The emission current changes, and it is difficult to control the electron emission amount by the pulse width. (3) When the voltage applied to the element is changed, the electric characteristics of the element are changed and the emission current is changed accordingly. (4) Due to the above problems, when it is used in the image forming apparatus, the brightness and color of the image change.

In the above-mentioned publication, these problems are caused by "the amount of organic molecules in the vacuum atmosphere around the surface of the electron-emitting device and around the device varies", and "the partial pressure of the organic molecules is minimized. By reducing the amount, stable electron emission characteristics can be obtained without fluctuations in emission current and device current. " Specifically, the partial pressure of the organic substance in the vacuum device is 1.3 × 10 ⁻⁶ Pa (1 × 10
^-8 Torr) or less is preferable, and further 1.3 × 10 ^-8
It is disclosed that Pa (1 × 10 ⁻¹⁰ Torr) or less is particularly preferable.

The pressure in the vacuum device is 1.3 × 10 ^-4.
It is stated that Pa or less, preferably 1.3 × 10 ⁻⁵ Pa or less, particularly preferably 1.3 × 10 ⁻⁶ Pa or less is desirable.

In this publication, the method of activation treatment is 10 ^-2 to 10 ^-3 Pa (10 ^-4 to 10 ^-5 To).
A method of applying a pulse voltage to a device in a vacuum of about rr) to deposit carbon or a carbon compound from an organic substance existing in the vacuum is disclosed. The electrical characteristics of the element subjected to such activation treatment show a characteristic that the element current If monotonously increases with respect to the element voltage Vf (MI characteristic) depending on the process, measurement conditions, etc., and voltage control. In some cases, it may exhibit negative resistance (VCNR characteristic). When the VCNR characteristic is exhibited, the characteristic changes depending on the measurement condition.
That is, the measurement result differs depending on the sweep speed of the element voltage during measurement, the standing time before measurement, the maximum value of the voltage applied during measurement, and the like. For example, when the sweep speed is fast, the measured characteristic itself is MI. It may be a characteristic. Also in this case, when the sweep speed is slowed down and the measurement is performed again, the VCNR characteristic is again exhibited. In any case, the emission current Ie shows MI characteristics, but the characteristics themselves change depending on the measurement conditions and are not stable.

By performing the stabilizing process and satisfying the above conditions, the relation between the element voltage and the element current is within the operating voltage range, that is, in the range where the voltage exceeding the maximum voltage applied in the normal operation is not applied. A monotonically increasing characteristic (MI characteristic) that is uniquely determined, that is, does not depend on the measurement conditions as described above, and at the same time, the relationship between the device voltage and the emission current is also uniquely determined, and the above problems are solved.

As described above, in order to stabilize the electron emission characteristics of the electron-emitting device, a stabilizing process is performed to remove the organic material, which is the source of the carbon-based film, from the periphery of the device. ing.

However, in this state, if the coating film containing carbon as the main component is lost for some reason, the original organic substance has been removed from the surroundings, and therefore cannot be recovered. When the electron-emitting device is driven for a long time, the coating film containing carbon as a main component is gradually lost,
In some cases, the electron emission characteristics deteriorated. Possible causes of the loss of the coating film are electric field evaporation due to the electric field applied to the electron emission portion 5, evaporation due to Joule heat generated by the flow of device current, etching due to ion bombardment, and the like. The present invention has been made in view of the above problems, and a main object thereof is to provide an image forming apparatus that suppresses deterioration of electron emission characteristics and further improves the life thereof.

Further, according to the present invention, in particular, an image is formed by using an electron source in which one or a plurality of electron-emitting devices having a coating film containing carbon as a main component are provided in the vicinity of the above-mentioned electron-emitting portion. It is also an object of the present invention to surely suppress deterioration of electron emission characteristics to realize further improvement of life and to prevent fluctuation of characteristics.

[0022]

Means for Solving the Problems The present invention, which achieves the above object, is, namely, a pair of element electrodes facing each other on a substrate, a conductive film connected to the pair of element electrodes, and a part of the conductive film. And an electron beam emitted from the electron source, the electron source having an electron emitting portion formed on the electron emitting portion, and an electron emitting element having a coating film containing carbon or a carbon compound as a main component in the vicinity of the electron emitting portion. An image forming member that forms an image by irradiation of, in an image forming apparatus including a vacuum container,
An organic substance gas is sealed in the vacuum container, the partial pressure of the organic substance gas is 1 × 10 ⁻⁶ Pa or more, and the total pressure in the vacuum container containing the organic substance is 1 × 10 ^{−. It is 3} Pa or less, and the average residence time of the organic substance molecules is shorter than the driving cycle of the electron source.

The partial pressure of the organic substance gas is 1 ×.
It is 10 ⁻⁴ Pa or more. Further, hydrogen gas is enclosed together with the gas of the organic substance in the vacuum container. The above organic substances are CH ₄ (methane), C ₂ H ₄ (ethylene), C ₂
It is characterized by being either H ₂ (acetylene) or C ₄ H ₂ (butadiene).

Further, the substrate has a pair of opposing element electrodes, a conductive film connected to the pair of element electrodes, and an electron-emitting portion formed on a part of the conductive film. An electron source including an electron-emitting device having an electron-emitting portion and a coating film containing carbon or a carbon compound as a main component in the vicinity thereof, and an image-forming member for forming an image by irradiation with an electron beam emitted from the electron source. A method of manufacturing an image forming apparatus which is enclosed in a vacuum container, wherein a forming step of forming the electron emitting portion, a gas of an organic substance is introduced into the vacuum container, and a pulse voltage is applied to the electron emitting element. An activation step of applying and depositing a coating film containing carbon or a carbon compound as a main component on the electron emission portion and its vicinity; and a stabilization step of removing an organic substance in the vacuum container after the activation step is completed, Electron emission device Organic substances having a short mean residence time than the dynamic period, or a mixed gas of the organic substance and hydrogen gas, characterized in that it has a gas introduction step of introducing into the vacuum chamber.

In the method of manufacturing the image forming apparatus, in the stabilizing step, the partial pressure of the organic substance having an average residence time longer than the driving cycle of the device is less than 1.0 × 10 ⁻⁶ Pa. To do. Also, in the stabilization step,
It is characterized in that the pressure in the vacuum container is set to less than 1.0 × 10 ⁻⁶ Pa. Furthermore, the organic substance introduced into the vacuum container in the activation step is the same substance as the organic substance introduced in the gas introduction step. Organic substances having an average residence time shorter than the driving cycle of the electron-emitting device are CH ₄ (methane), C ₂ H ₄
(Ethylene), C ₂ H ₂ (acetylene), or C ₄ H ₂ (butadiene).

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION In order to prevent the above-described deterioration of the characteristics of the electron-emitting device, in order to cause a new deposition commensurate with the loss of the above-mentioned carbon-based coating, the organic material from which it is based It is conceivable to introduce the above into the vacuum container of the image forming apparatus, but if the organic substance remains around the electron-emitting device as described above, various disadvantages will appear in the electron-emitting characteristics. Therefore, the present invention can replenish a film containing carbon as a main component, which is lost by driving, suppress deterioration of electron emission characteristics, and further improve life without causing such inconvenient characteristics. It was done by finding a way to do it. The present invention will be described in detail below.

The inventor of the present invention uses the inside of a vacuum container of an image forming apparatus (which cannot be said to be a “vacuum container” in the strict sense because a gas is enclosed in the container, but is hereinafter referred to as a “vacuum container” for convenience). It has been found that the object can be achieved by sufficiently removing the organic substance remaining in the above, and then filling the gas of the organic substance having a short average residence time in a vacuum container.

Further, when a gas in which hydrogen gas is mixed with the gas of the organic substance having the above short average residence time is used, there is an effect such that the generation of leak current can be effectively prevented,
I found it even better.

Here, the average residence time is an average time from when the molecule is once adsorbed to the inner wall of the vacuum container or the surface of the substrate to when it is desorbed. This is affected by conditions such as the mass of the molecule and the presence or absence of polarization, and strictly speaking depends on the adsorbing partner. The adsorption of gas molecules on the solid surface includes physical adsorption and chemical adsorption, but the main focus here is physical adsorption. The adsorption energy of chemisorption is extremely large, and gas molecules once chemisorbed are not easily desorbed, and such a gas that is likely to be adsorbed is not suitable as a gas to be sealed in a vacuum container in the present invention. . When the adsorption energy of physical adsorption is U, the average residence time τ is

[0030]

[Equation 1] Given by Here, k is Boltzmann's constant and T is temperature. τ ₀ is an amount called “frequency factor” and the like, which is 10 ⁻¹³ sec. Has a value of the degree.

Calorific value E when 1 mol of gas molecule is adsorbed
Is called heat of adsorption, and the above-mentioned adsorption energy is E =
There is a relationship of N _a U. Here, N _a is Avogadro's number. Strictly speaking, the heat of adsorption of gas molecules, that is, the adsorption energy U, is not completely unique because it depends on the partner to be adsorbed, but it is usually slightly larger than the heat of vaporization, and for some gases, The maximum value that can be taken is estimated.

For example, "Practical Vacuum Technology Guide (Technolo
gy of Vacuum) "(edited by the committee for editing practical vacuum technology
Published by Industrial Technology Service Center Co., Ltd., 1990, 11
The value of the adsorption heat is illustrated in Table 1.1 of the month 26) p60, when fix the value of the adsorption ^{_{energy, CH 4: 3.47 × 10 -20}} ( unit Joule _{(J)), C 2 H} 4 : 5.55 × 10 ⁻²⁰ , C ₂ H ₂ : 6.25 × 10 ⁻²⁰ . When the value of the average residence time τ at an absolute temperature of 300 K is calculated by the above formula (1), CH ₄ : 4.35 × 10 ⁻¹⁰ sec. , C ₂ H ₄ : 6.60 × 10 ⁻⁸ sec. , C ₂ H ₂ : 3.57 × 10 ⁻⁷ sec. The values of and are obtained.

For a gas molecule having a large value of the average residence time τ, this value can be relatively easily experimentally obtained. The apparatus used for the measurement is one in which two vacuum vessels 141 and 142 are connected by a thin tube 144 having a length 1 and an inner radius r, as shown in FIG. 15, and a gate valve 143 is provided on one side. . A gas to be measured is put into the vacuum container 141, and the pressure is set to p ₀ . However, as will be described later, when the gate valve 143 is opened and the gas flows through the pipe 144, the pressure should not be so high as to give a viscous flow.
The inside of the vacuum container 142 is evacuated so that the pressure is sufficiently lower than p ₀ . A pressure gauge 145 is attached to the vacuum container 142 so that the internal pressure can be measured. When the gate valve 143 is opened, the pressure p inside the vacuum container 142 becomes
It increases with time. In the state where the pressure inside the vacuum container 141 does not change largely from p ₀ , the change in the pressure p gradually approaches the straight line indicated by the broken line with time as shown in FIG. If the value of the point where this straight line cuts the time axis is t = L, approximately,

[0034]

[Equation 2] It can be expressed as. Where β is the "roughness coefficient",
With a tube having a smooth inner surface, it can be set to approximately 1. s is the adsorption probability, which indicates the probability that molecules that collide with the inner wall of the tube will be adsorbed without being elastically scattered. However, in the case of molecules with a large average residence time τ, most molecules are adsorbed. Therefore, it may be regarded as 1.
Therefore, by measuring the change in the pressure of the vacuum container 142, it is possible to estimate the approximate value of the average residence time τ. For this measurement method, see Goro Tominaga et al. "Measurement of average residence time of oil molecules by unsteady flow method (I)"("
A Measurement of Mean Absorption Time of Oil Molec
ules by the Non-StationaryFlow Method (Part I) ”)
Vacuum, Vol.6, p320-328, 1963.

The cause of the phenomenon described above is as follows:
Although not surely understood, it may be understood to some extent by the following picture.

The carbon-based coating film deposited on the electron-emitting portion 5 plays an important role in electron emission. That is, as schematically shown in FIG. 2C, by depositing a coating film containing carbon as a main component around the crack formed in the conductive film 4, a fissure is formed by the deposit 6. To be done. It is believed that this crack needs to be somewhat narrow in order to produce good electron emission.

When the electron-emitting device is driven in this portion,
A strong electric field is applied or a current flows to generate Joule heat, whereby the coating film containing carbon as a main component is evaporated and gradually lost.

Also, the gas molecules remaining in the vacuum chamber are ionized by colliding with the electrons emitted from the electron-emitting device, whereby the above-mentioned carbon-based coating film is sputtered. The coating film is lost, and these effects spread the cracks described above and reduce the electron emission amount. On the other hand, the organic substance molecules enclosed in the vacuum container are adsorbed, and the energy accompanying the electron emission is applied to the vicinity of the electron emission portion 5, whereby the deposition of the film containing carbon as a main component proceeds, The release amount increases.

If both of the above processes occur at the same time and the two are balanced, the coating film containing carbon as the main component will not be lost, deterioration will not occur, and stable characteristics will be obtained. It is most preferable that the two are perfectly balanced and the characteristics do not change at all at all, but even if there is some change, it may be within a range that causes no practical problem. Creating such a situation may seem to restore the state before the stabilization treatment, but by using an organic substance with a short average residence time τ, the characteristics obtained by the stabilization treatment can be maintained. can do.

The influence of the average stay time τ is estimated to be as follows.

As described above, the change in the electrical characteristics of the electron-emitting device is related to the change in the coating film containing carbon as the main component formed around the electron-emitting portion 4, but not only that. It is considered that the state of the organic substance molecules adsorbed in the vicinity of the electron emission portion 5 is also affected even if the film is not formed. That is, by adsorbing the organic substance molecules in the vicinity of the electron emitting portion 5, the crack width of the electron emitting portion 5 is effectively narrowed further, and in some cases a partial current flow path is formed, so that the device The current If becomes large.

When the electron-emitting device is driven by applying a pulse voltage, a part of the adsorbed organic molecules are desorbed due to an electric field or Joule heat when the pulse is applied (at this time, the organic molecules are desorbed). Other parts of the substance molecule, there is also a part that changes to a coating film containing carbon as the main component). On the other hand, during the pause period of the pulse, organic molecules fly from the surrounding gas phase and are adsorbed. It can be considered that this balance determines the electrical characteristics.

Consider a case where the pulse voltage is applied at regular intervals and the pulse application is temporarily stopped when the element exhibits constant electrical characteristics. When the average residence time of the organic molecules is longer than the above pulse interval, the adsorption amount of the organic substance molecules increases while the pulse application is stopped, and when the pulse application is restarted next, the device current If is increased. Increase temporarily. The emission current Ie is also affected and changes. In an actual image forming apparatus, a pixel becomes dark for a certain period,
When it becomes brighter next time, it becomes different from the normal brightness, which is not preferable. On the other hand, if the average residence time τ of the organic substance molecules is shorter than the pulse interval, the adsorption amount of the organic substance molecules reaches equilibrium when the pulses are applied at regular intervals, and the pulse application interval is further extended. However, since the adsorption amount of the organic substance molecules does not change, such a phenomenon does not occur, which is preferable for the image forming apparatus.

It is considered that the phenomenon that the emission current changes depending on the pulse width of the driving pulse and the reason that the rest time of the pulse also changes depending on the change of the pulse width.
Therefore, it is likely that the present invention solves this problem by the same operation as described above.

The pulse interval is the driving cycle of the element in an actual device. Therefore, the average residence time of organic substances τ
Must be shorter than the driving cycle.

It is considered that the electrical characteristics change depending on the drive pulse voltage, mainly because the amount of organic substance molecules adsorbed in the vicinity of the electron emission portion changes depending on the drive pulse voltage. For example, considering a process in which organic substance molecules are separated by an electric field, when the adsorption amount of organic substance molecules is increased and the effective width of the crack is narrowed, the electric field acting on the organic substance molecules is increased and the separation due to the electric field is increased. Will increase. The characteristics of the device temporarily settle when the amount of detachment is balanced with the amount of adsorption. Next, when the crest value of the pulse voltage is reduced, the amount of desorption due to the electric field decreases, so the amount of adsorption of organic substance molecules increases until the width of the crack becomes narrower,
Eventually they will balance. Not only desorption due to an electric field but also desorption due to Joule heat can be considered in the same manner. On the other hand, in the case of an organic substance molecule having a short average residence time τ, in an atmosphere having a partial pressure of the organic substance of the present invention, the adsorption amount itself is relatively small due to the short average residence time, and the adsorption amount is somewhat small. Even if it changes, it is considered that the electrical characteristics are not seriously affected.

In any case, by selecting the organic substance to be sealed by paying attention to the average residence time τ, the relation between the device current If and the device voltage Vf can be determined by measuring the device while the organic substance is present in the atmosphere. The MI characteristic that the element current If is uniquely determined with respect to the element voltage Vf, which does not depend on the sweep speed of the voltage or the maximum value of the voltage applied during measurement (however, the range that does not exceed the voltage applied during normal driving). The above problems, the temporary increase of the emission current immediately after the drive is stopped, the dependence of the emission current on the pulse width, the change in the electrical characteristics due to the pulse voltage, and the driving It was found that it is possible to suppress the deterioration of the electron emission amount.

The above characteristics are as schematically shown in FIG. 21, and the element current If has a threshold value V'th with respect to the element voltage Vf, and when the element voltage Vf is V'th or less. I
f is substantially 0, and increases monotonically with Vf at V'th and above. This characteristic is uniquely determined in the range where the applied voltage during measurement does not exceed the voltage applied during driving. At this time, the emission current Ie also exhibits a monotonically increasing characteristic having the threshold value Vth, and this characteristic is also uniquely determined. Since the magnitudes of the device current If and the emission current Ie are very different, they are shown in arbitrary units. Both are linear scales. The partial pressure of the organic substance to be enclosed is
If it is too small, the effect of depositing a carbon-based coating becomes insufficient. On the other hand, including organic substance gas,
If the total pressure of the gas in the vacuum container is too large, discharge may occur inside the container, so there is an upper limit. As a result of the examination,
The partial pressure of the organic substance gas needs to be 1 × 10 ⁻⁶ Pa or more. Further, the pressure for generating no discharge depends on the structure of the device and the kind of gas, but it is possible to form a preferable image in the structure of an actual flat image forming device such as the embodiment described later. It was found that the upper limit of the total pressure in the container should be about 1 × 10 ⁻³ Pa so that no discharge occurs when an anode voltage of several kV is applied.

When the stabilization treatment is insufficient and an organic substance having a long average residence time τ remains, a new organic substance gas having a short average residence time τ is charged, the above-mentioned problem is solved. It is natural that it is not done. Therefore, it is indispensable to the present invention to remove the organic substances sufficiently by the stabilization treatment. The organic substance having a long average residence time τ includes not only a substance introduced during the activation treatment but also a substance unintentionally adsorbed inside the vacuum container and a substance diffused from the exhaust device. Therefore, the stabilization process must be strictly performed in consideration of these.

By the stabilization treatment, the partial pressure of the organic substance having a long average residence time τ is within the range described in JP-A-7-235275, that is, a partial pressure of 1.3 × 10 ⁻⁶ Pa or less. I have to hold back. Also, the atmosphere in the vacuum container of the finally manufactured image forming apparatus should satisfy the same condition regarding the partial pressure of the organic substance having a long average residence time τ.

The effect of mixing hydrogen gas at the same time as the organic substance gas in the vacuum vessel is considered as follows. Hydrogen radicals are thought to have the function of etching the carbon-based coating formed in the electron emission region, but organic substances such as methane originally contain hydrogen atoms in their molecules, and When the bond is broken, hydrogen radicals are generated, which etches the film. In particular, due to insufficient polymerization of molecules, a portion having low stability is swiftly etched. As a result, a portion of the coating film containing carbon as a main component that does not contribute much to electron emission and serves as a path of the leakage current (the portion has a small energy provided by driving the element, so that the carbonization proceeds too much. However, since it is likely to be etched), it is expected to be removed preferentially to improve the electron emission efficiency.

For example, in the case of methane, the molecular formula is CH ₄ , and if one of the hydrogen bonds is broken and a hydrogen radical is generated, the amount of C and H radicals becomes 1: 1. However, not all methane molecules actually release hydrogen radicals like this, and this is just a simplified argument. In addition to methane, for example, ethane, ethylene, acetylene, etc., the number of carbon atoms per molecule is larger than that of methane, and the number of carbon atoms is larger than the number of hydrogen radicals generated, which is expected to reduce the above-described etching effect. Mixing hydrogen gas increases the number of hydrogen radicals relative to the number of carbon atoms contained in the organic substance,
This is intended to increase the etching effect.
However, when the bond of one hydrogen molecule is broken, two hydrogen radicals are generated, but since the bond of hydrogen molecule H ₂ is strong, the bond is hard to break, and the ratio of generating hydrogen radical will be lower than that of an organic substance. Therefore, the amount of introduced hydrogen does not directly increase the amount of hydrogen radicals, but it is necessary to introduce a certain amount of hydrogen for the effect to appear. The present invention will be described in more detail below with reference to preferred embodiments.

An electron-emitting device used in the present invention, for example, a surface conduction electron-emitting device, is schematically shown in FIGS. 2A, 2B and 2C, and this electron-emitting device is mounted on a substrate. Formed in large numbers and used as an electron source.

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

First, a method of manufacturing an image forming apparatus using an electron source having a simple matrix arrangement will be described. FIG. 3 schematically shows the structure of an electron source having a simple matrix arrangement. FIG.
In the figure, 31 is a substrate, 32 is an X-direction wiring, and 33 is a Y-direction wiring. Reference numeral 34 is a surface conduction electron-emitting device, and 35 is a wire connection.

The m X-direction wirings 32 are Dx1 and 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. Y
The directional wiring 33 is composed of n wirings Dy1, Dy2, ..., Dyn, and is formed similarly to the X-directional wiring 32. An interlayer insulating layer (not shown) is provided between the m number of X-direction wirings 32 and the n number of Y-direction wirings 33 to electrically separate the two (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 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 31 on which the X-direction wiring 32 is formed, and particularly, in order to withstand the potential difference at the intersection of the X-direction wiring 32 and the Y-direction wiring 33, the film thickness, The material and manufacturing method are set appropriately. The X-direction wiring 32 and the Y-direction wiring 33 are drawn out as external terminals.

A pair of electrodes (not shown) forming the surface conduction electron-emitting device 34 are electrically connected by m X-direction wirings 32, n Y-direction wirings 33 and a connection 35 made of a conductive metal or the like. Has been done.

The material forming the wiring 32 and the wiring 33, the material forming the connection 35, 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 the row of the surface conduction electron-emitting devices 34 arranged in the X direction is connected to the X-direction wiring 32. On the other hand, a modulation signal generating means (not shown) for modulating each column of the surface conduction electron-emitting devices 34 arranged in the Y direction according to an input signal is connected to the Y-direction wiring 33. 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.

An image forming apparatus constructed by using an electron source having such a simple matrix arrangement will be described with reference to FIGS. 4, 5, and 6. 4 is a schematic diagram showing an example of a display panel of the image forming apparatus, and FIG. 5 is a schematic diagram of a fluorescent film used in the image forming apparatus of FIG.

In FIG. 4, 31 is a substrate on which a plurality of electron-emitting devices 34 are arranged, 41 is a rear plate on which the substrate 31 is fixed, 46 is a face on which a fluorescent film 44, a metal back 45 and the like are formed on the inner surface of a glass substrate 43. It is a plate. Four
Reference numeral 2 denotes a support frame. The rear plate 41 and the face plate 46 are joined to the support frame 42 by using frit glass having a low melting point. Reference numerals 32 and 33 denote an X-direction wiring and a Y-direction wiring connected to a pair of device electrodes of the surface conduction electron-emitting device.

The vacuum container 47 is composed of the face plate 46, the support frame 42, and the rear plate 41 as described above. Since the rear plate 41 is provided mainly for the purpose of reinforcing the strength of the substrate 31, if the substrate 31 itself has sufficient strength, the separate rear plate 41 can be omitted. That is, the support frame 42 may be directly sealed to the substrate 31, and the face plate 46, the support frame 42, and the substrate 31 may constitute the vacuum container 47. On the other hand, face plate 4
6. A vacuum container 47 having sufficient strength against atmospheric pressure can also be formed by installing a support body (not shown) called a spacer between the rear plate 41.

FIG. 5 is a schematic diagram showing a fluorescent film. In the case of monochrome, the fluorescent film 44 can be composed of only a fluorescent material. In the case of a color fluorescent film, it can be composed of a black conductive material 51 called a black stripe (A) or a black matrix (b) and a fluorescent material 52 depending on the arrangement of the fluorescent materials. In the case of color display, the purpose of providing the black stripes and the black matrix is to make the color mixture or the like inconspicuous by blackening the separately-applied portions between the phosphors 52 of the three primary color phosphors, and to prevent the external appearance of the phosphor film 44. This is to suppress the 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 of applying the phosphor to the glass substrate 53, a precipitation method, a printing method or the like can be adopted regardless of monochrome or color. A metal back 45 is usually provided on the inner surface side of the fluorescent film 44. The purpose of providing the metal back 45 is to improve the brightness by specularly reflecting the light toward the inner surface side of the light emission of the phosphor toward the face plate 46 side, and to act as an electrode for applying an electron beam acceleration voltage. , Protecting the phosphor from damage due to collision of negative ions generated in the vacuum container. The metal back 45, after forming the fluorescent film, smoothes the inner surface of the fluorescent film (normally called “filming”).
And then depositing Al using vacuum deposition or the like.

The face plate 46 is further provided with a fluorescent film 4
In order to improve the conductivity of No. 4, a transparent electrode may be provided on the outer surface side of the fluorescent film 44.

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. An example of a method of manufacturing the image forming apparatus shown in FIG. 4 will be described below.

FIG. 6 is a schematic view showing the outline of the apparatus used in this step. The image forming apparatus 61 is connected to a vacuum chamber 63 via an exhaust pipe 62, and is further connected to an exhaust apparatus 65 via a gate valve 64. A pressure gauge 66, a quadrupole mass spectrometer (Q-mass) 67, and the like are attached to the vacuum chamber 63 in order to measure the internal pressure and the partial pressure of each component in the atmosphere. Since it is difficult to directly measure the pressure inside the vacuum container 47 of the image display device 61, the pressure inside the vacuum chamber 63 is measured to control the processing conditions.

A gas introduction line 68 is connected to the vacuum chamber 63 in order to introduce a necessary gas into the vacuum chamber to control the atmosphere. An introduction substance source 610 is connected to the other end of the gas introduction line 68, and the introduction substance is stored in an ampoule, a cylinder or the like. In the middle of the gas introduction line, an introduction control means 69 for controlling the rate of introducing the introduction substance is provided. As the introduction amount control means 69, specifically, a valve capable of controlling the flow rate to be escaped such as a slow leak valve,
A mass flow controller or the like can be used depending on the type of introduced substance.

The inside of the vacuum container 47 is evacuated and forming is performed by the apparatus shown in FIG. At this time, for example, as shown in FIG. 7, the Y-direction wiring 33 is connected to the common electrode 71, and X
Forming can be performed by simultaneously applying voltage pulses to the element connected to one of the directional wirings 32 by the power supply 72.

Further, by sequentially applying (scrolling) the phase-shifted pulses to the plurality of X-direction wirings, it is possible to collectively form the elements connected to the plurality of X-direction wirings. In the figure, 73 is a resistance for current measurement, and 74 is an oscilloscope for current measurement. With these, the applied current / voltage waveform can be observed.

After the forming is completed, an activation process is performed.
As shown in FIG. 6, the organic substance is introduced from the gas introduction line 68 into the vacuum container 47 after being sufficiently evacuated. As the organic substance used in this step, a substance having a too long average residence time is inappropriate. As will be described later, in the stabilization step, the organic substance must be sufficiently removed, but if the average residence time τ is too long, it will be extremely difficult to remove. Examples of organic substances that can be preferably used include, for example, methane, ethane, ethylene, acetylene,
Examples thereof include propylene, butadiene, n-hexane, benzene, nitrobenzene, toluene, o-xylene, benzonitrile, chloroethylene, trichloroethylene, methanol, ethanol, isopropanol, ethylene glycol and acetone. Of these, if the same organic substance as that introduced in the gas introduction step described later is used, there is no concern that this will remain at the end and have an adverse effect, and since the average residence time τ is short, it is removed from the vacuum container. It is also preferable because it is relatively easy. In addition, substances other than organic substances may be introduced as needed.

By applying a voltage to each electron-emitting device in the atmosphere thus formed containing an organic substance, a film containing carbon as a main component is deposited on the electron-emitting portion, and the electron emission amount is reduced. Drastic rise. As a voltage application method at this time, a voltage pulse may be simultaneously applied to the elements connected to one directional wiring by the same connection as in the case of forming.

After the activation process, the stabilization process is performed as in the case of the individual device. Heat the vacuum vessel 47 to 8
While maintaining the temperature at 0 to 250 ° C., gas is exhausted through an exhaust pipe 62 by an oil-free exhaust device 65 such as an ion pump or a sorption pump to create an atmosphere with a sufficiently small amount of organic substances. In this step, if the organic substance having a long average residence time τ remains without being sufficiently exhausted, it causes the instability of the characteristics of the electron-emitting device as described above, and the object of the present invention cannot be achieved. Therefore, it is necessary to make the partial pressure of the organic substance less than 1.0 × 10 ⁻⁶ Pa.

Also, water is used for msec. Since it has a relatively long average residence time τ of the order, it may take time to exhaust sufficiently. Water is often the main component of the residual gas in the vicinity of 10 ⁻³ to 10 ⁻⁶ Pa while exhausting the inside of the vacuum container to reduce the pressure. When it is attempted to introduce an organic substance gas or a mixed gas of an organic substance and hydrogen to a desired pressure in the gas introduction step described later with such residual gas remaining, it is possible to appropriately control the introduction amount. It gets harder. Therefore, in this process, the above average stay time τ
Of not only long partial pressure of the organic substance, the pressure itself of the vacuum chamber 1.0 × 10 ^- it is more desirable to sufficiently exhaust to be less than ⁶ Pa.

Thereafter, a gas introducing step of introducing a gas of an appropriate organic substance or a mixed gas of an organic substance and hydrogen is performed, and the exhaust pipe is heated by a burner to be melted and sealed. A getter process may be performed to maintain the atmosphere after the vacuum container 47 is sealed. This getter process is performed by heating using resistance heating, high frequency heating, or the like immediately before or after sealing the vacuum vessel 47.
In this process, a getter placed at a predetermined position (not shown) in 7 is heated to form a vapor deposition film. Getter is usually B
The main component is a and the like, and the adsorbing action of the deposited film removes water, oxygen, and the like released from the wall surface of the vacuum container after sealing and maintains the atmosphere in the vacuum container 47.

Next, a ladder type electron source and an image forming apparatus will be described with reference to FIGS. 8 and 9.

FIG. 8 is a schematic diagram showing an example of a ladder-type electron source. In FIG. 8, 81 is a substrate and 82 is an electron-emitting device. 83 and Dx1 to Dx10 are common wirings for connecting the electron-emitting devices 82. A plurality of electron-emitting devices 82 are arranged in parallel in the X direction on the substrate 81 (this is called a device row). A plurality of the element rows are arranged to constitute an electron source. By applying a drive voltage between the common wires of each element row, each element row can be driven independently. That is, a voltage equal to or higher than the electron emission threshold is applied to an element row that wants to emit an electron beam, and a voltage equal to or lower than the electron emission threshold is applied to an element row that does not emit an electron beam. Common wiring Dx2 to Dx9 between each element row
Is, for example, Dx2 and Dx3 have the same wiring, and Dx1, Dx
It is also possible to drive x4 individually.

FIG. 9 is a schematic view showing an example of a panel structure in an image forming apparatus provided with a ladder-type electron source. The rear plate, face plate, etc. are the same as those in FIG. In FIG. 9, 91 is a grid electrode, 92 is a hole for passing electrons, and 93 is Dox1, Dox.
2,. . . An external terminal made of Doxm. 94
Is G1, G connected to the grid electrode 91
2,. . . . A terminal outside the container made of Gn, and 95 is a substrate. In FIG. 9, the same parts as those shown in FIGS. 4 and 8 are designated by the same reference numerals as those shown in these figures. The major difference between the image forming apparatus shown here and the image forming apparatus having the simple matrix arrangement shown in FIG.
1 and whether or not the grid electrode 91 is provided between the face plate 46.

In FIG. 9, a grid electrode 91 is provided between the substrate 81 and the face plate 46. The grid electrode 91 is for modulating the electron beam emitted from the surface conduction electron-emitting device, and the electron beam is applied to the stripe-shaped electrode provided orthogonally to the device rows in the ladder type arrangement. 1 for each element to pass
Circular openings 92 are provided one by one. The shape and installation position of the grid are not limited to those shown in FIG. For example, a large number of passage openings may be provided in a mesh shape as openings, and a grid may be provided around or near the surface conduction electron-emitting device.

The terminal 93 outside the container and the terminal 94 outside the grid container are electrically connected to a control circuit (not shown).

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

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 and 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.

Normal television (NTSC, PAL
The driving frequency in () is 30 Hz corresponding to the driving cycle of the vertical synchronizing signal of about 33 msec, and the driving frequency in the computer terminal is about 60 Hz corresponding to the driving cycle of about 16.7 msec. In the case of expressing the luminance gradation by the modulation by the pulse width and the modulation by the pulse peak value, the organic substance gas in the vacuum container may have an average stay period shorter than each driving cycle as described above. , Effective for displays for televisions and computer terminals.

It is also possible to express the brightness gradation by modulating the number of times that a pulse voltage having a constant pulse peak value and a constant short pulse width is applied within a constant time.
In this case, the drive cycle is, for example, μsec. The average residence time of methane, ethylene, and acetylene is sufficiently short as described above, although it may be extremely short, but the present invention can be realized even in such a case.

Hereinafter, the present invention will be described in more detail based on more specific examples.

[0087]

【Example】

[Embodiment 1] This embodiment is an example of an electron source in which a large number of surface conduction electron-emitting devices are arranged in a simple matrix.

A plan view of a part of the electron source is shown in FIG.
A sectional view taken along the line AA in the figure is shown in FIG. 11, and a manufacturing procedure is shown in FIGS. Here, 1 is a substrate, 102 is an X-direction wiring, 103 is a Y-direction wiring (also referred to as upper wiring),
2, 3 are device electrodes, 4 is a thin film including an electron emitting portion, 104
Is an interlayer insulating layer, and 105 is a contact hole for electrically connecting the device electrode 2 and the lower wiring 102.

Next, the manufacturing method will be concretely described in the order of steps with reference to FIG. In addition, each process (A)-(H)
Corresponds to A to (D) in FIG. 12 and (E) to (H) in FIG.

(Step A) On a substrate 1 in which a 0.5 μm-thick silicon oxide film was formed on a cleaned soda-lime glass by a sputtering method, Cr having a thickness of 5 nm and Au having a thickness of 600 nm were formed by a vacuum deposition method. Then, the photoresist (A
(Z1370, Hoechst) is spin-coated with a spinner, baked, and then exposed and developed with a photomask image,
The lower wiring 102 was formed, and the Au / Cr deposited film was wet-etched to form the lower wiring 102 having a desired shape.

(Step B) Next, an interlayer insulating layer 104 made of a silicon oxide film having a thickness of 1.0 μm was deposited by the RF sputtering method.

(Step C) A photoresist pattern for forming the contact hole 105 is formed in the silicon oxide film deposited in the step B, and the interlayer insulating layer 1 is used as a mask.
04 was etched to form a contact hole 105. The etching is performed by RIE (Reac) using CF ₄ and H ₂ gas.
tive Ion Etching) method.

(Step D) After that, a pattern to be the device electrodes 2 and 3 and the gap G between the device electrodes is formed with a photoresist (RD-2000N-41, manufactured by Hitachi Chemical Co., Ltd.), and a thickness of 5 nm is formed by a vacuum deposition method. Ti, thickness 100
nm of Ni was sequentially deposited. The photoresist pattern was dissolved in an organic solvent and the Ni / Ti deposited film was lifted off to form device electrodes 2 and 3 having a device electrode interval of 3 μm and a width of 300 μm.

(Process E) Upper wiring 1 on device electrodes 2 and 3
After forming the 03 photoresist pattern, the thickness is 5 nm.
Ti and Au having a thickness of 500 nm were sequentially deposited by vacuum evaporation, and unnecessary portions were removed by lift-off to form the upper wiring 103 having a desired shape.

(Step F) Next, the Cr film 1 having a film thickness of 30 nm is formed.
06 was deposited by vacuum evaporation, patterned so as to have an opening in the shape of the conductive film 4, and a Pd amine complex solution (ccp4230) was spin-coated thereon by a spinner, and heated and baked at 300 ° C. for 12 minutes. Apply Pd
A conductive film 107 made of O particles was formed. The thickness of this film was 70 nm.

(Step G) The Cr film 106 was wet-etched using an etchant and removed together with unnecessary portions of the conductive film 107 made of PdO fine particles to form the conductive film 4 having a desired shape. Resistance value is Rs = 4 × 10 ⁴ Ω
It was about / □.

(Process H) A resist pattern is formed on portions other than the contact hole 104, and the thickness of the resist pattern is reduced to 5 by vacuum evaporation.
nm Ti and Au 500 nm thick were sequentially deposited. Unnecessary portions were removed by lift-off to bury the contact holes.

An image forming apparatus was constructed by using the electron source thus created. As shown in FIG. 4, after the substrate 31 is fixed on the rear plate 41, the face plate 46 (the fluorescent film 44 and the metal back 45 are formed on the inner surface of the glass substrate 43 is formed 5 mm above the substrate 31. )
Was placed via the support frame 42, and frit glass was applied to the joint portion of the face plate 46, the support frame 42, and the rear plate 41, and baked at 400 ° C. for 10 minutes in the air to seal them. The frit glass was also used to fix the substrate 31 to the rear plate 41. The distance between the substrate 31 and the face plate 41 was 5 mm.

In the case of monochrome, the fluorescent film 44 is composed of only the fluorescent material, but 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. The fluorescent film 44 was prepared. As the material for the black stripe, a material mainly containing graphite, which is generally used, was used. A slurry method was used to apply the phosphor to the glass substrate 43.

A metal back 45 is provided on the inner surface side of the fluorescent film 44. The metal back 45 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.

On the face plate 46, the fluorescent film 4 is further provided.
A transparent electrode may be provided on the outer surface side of the fluorescent film 44 in order to enhance the conductivity of No. 4, but in the present embodiment, the metal back 45 alone provided sufficient conductivity, so it was omitted.

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.

The image forming apparatus formed as described above is connected to a vacuum apparatus as shown in FIG. 6 and is evacuated to a pressure of about 10 ⁻⁴ Pa. Then, as shown in FIG. The wiring 33 is connected to the common electrode 71, and a forming process is performed for each line in the X direction. The pulse voltage used for this processing has a pulse width of 1 msec. , Pulse interval 10mse
c. This is a triangular wave pulse whose pulse peak value gradually increases.

After performing the forming process for all the lines, the activation process is performed. The activation process was performed by introducing n-hexane into the vacuum vessel to adjust the pressure to 2.7 × 10 ⁻² Pa and applying a pulse voltage as in the forming process. However, the pulse peak value was a constant value of 15V.

After completion of the activation step, stabilization treatment was performed.
FIG. 14 is a schematic cross-sectional view in which a portion of the image display device 61 of FIG. 6 is separately installed for enlarged display or stabilization processing. The rear plate 41, the substrate 31, the electron-emitting device 34, the glass substrate 43, the fluorescent film 44, An image forming apparatus including a metal back 45, a face plate 46, and a support frame 42, a heater 131 is provided in the vertical direction of the image forming apparatus, and an exhaust pipe 132 is pre-drilled in the support frame 42. As schematically shown in FIG. 14, the vacuum vessel was sandwiched between the heaters 131 and heated and evacuated, and the pressure was lowered to 1 × 10 ⁻⁸ Pa.

A quadrupole mass (Q-
mass) analyzer was connected and the residual gas was examined.
-Hexane was not observed, confirming that it was sufficiently removed from the vacuum vessel. Then, a gas introduction process is performed. Methane was introduced into the vacuum vessel to adjust the pressure to 2 × 10 ⁻⁴ Pa. Wiring is omitted in FIG. 14 to simplify the drawing.

After that, after confirming that the display function works normally and the characteristics are stable, the exhaust pipe 132 is heated by a gas burner to be welded, sealed, and a getter (not shown) is applied by high-frequency heating. A getter process was performed by heating.

[Comparative Example 1] By the same steps as in Example 1, the activation process was performed, and then the vacuum vessel was evacuated to perform the stabilization process, and then the exhaust pipe was introduced without introducing methane. A getter (not shown) was heated by high-frequency heating to perform getter treatment.

Comparative Example 2 The same steps as in Example 1 were performed until the activation step, after which the vacuum vessel was evacuated for stabilization treatment, and then ethylene glycol was used instead of methane in the gas introduction step. (HOCH ₂ CH ₂ OH) was introduced.

As described above, the average residence time τ of methane is at most nsec. While it is considered to be a value of the order, the average residence time τ of ethylene glycol measured by the method described above is several tens of msec. Or more

The screens of Example 1 and Comparative Examples 1 and 2 were made to emit light at a drive frequency of 60 Hz. Therefore, the driving cycle is 16.7 msec. The mean residence time τ of methane is much shorter than this, and that of ethylene glycol is a little longer. The potential of the metal back was set to 1 kV and the emission current value was measured.

FIG. 18 schematically shows the measurement results of Example 1 and Comparative Example 2, in which the change in emission current was measured when the application of the pulse voltage was interrupted for 10 seconds and then the application was restarted. It is a thing. Comparative example 2 shown in FIG.
However, the value of Ie increases immediately after the reappearance of the pulse application and returns to the original value with the passage of time, whereas in Example 1 shown in (b) in the figure, the influence of the interruption of the pulse application is not seen. . This is because the average residence time of ethylene glycol is longer than the normal pulse interval as described above, so that the adsorption progresses while the pulse is stopped and a large emission current is generated after the pulse application is restarted. .

This phenomenon is such that, when an image is actually displayed, after a certain pixel continues to be in a black state and the image changes, and the fluorescent film emits light, it becomes brighter than desired brightness. Corresponding and undesirable.

After that, in the above image forming apparatus, X
One row in the direction was selected and the pulse was applied only to this row, and the following measurement was performed.

Pulse interval 16.7 msec. , Peak value 1
5V rectangular wave pulse is applied and pulse width is 2 to 8 mse
c. And the emission current value was observed. Example 1
In contrast, a constant emission current value was observed regardless of the pulse width, whereas in Comparative Example 2, it was observed that the emission current value decreased as the pulse width increased.

Next, the pulse interval is 16.7 msec. , Pulse width 30 μsec. The Vf-If characteristic was measured by applying a triangular wave pulse of and measuring the emission current. After measuring the peak value as 15 V, the peak value was changed to 10 V and the measurement was performed again. In the image forming apparatus of Example 1, no difference was found in both measurements, but in Comparative Example 2, the element current and the emission current gradually increased for a while after the measurement of the peak value 10 V was started, and the electrical It was observed that the characteristics changed.

Next, Vf was applied to the same element row as above with a sweep time of 10 seconds, varying from 0V to 15V, and the electrical characteristics were measured. For the device of Example 1, the same results as measured with the above triangular wave pulse, ie, FIG.
The MI characteristics as shown in (3) were obtained regardless of the difference in the measurement conditions. In the device of Comparative Example 2, the above-mentioned VCNR characteristic was observed for the If-Vf voltage identification.

[Example 2] and [Comparative Example 3] By the same steps as in Example 1, 1 × 10 ⁻⁶ Pa to 1 × 10 ⁻³ Pa shown in a to d of FIG. The image forming apparatus was prepared as Comparative Example 3 in which the partial pressure of methane introduced was less than 2 × 10 ⁻⁷ Pa and 5 × 10 ⁻³ Pa or more.

[Comparative Example 4] By the same steps as in Example 1, the partial pressure of methane to be introduced was set to 1 x 10 ^-3 Pa, helium gas was further introduced, and the total pressure in the vacuum vessel was set to 5 x. The pressure was set to 10 ⁻³ Pa.

The samples prepared in Examples 2, Comparative Examples 3 and 4 were measured for emission current Ie in the same manner as in Example 1 and the values obtained 1 hour after the start of measurement were compared, as shown in FIG. It was As a result, the preferable methane pressure is 1 × 10 ⁻⁶ Pa.
It was found that the range was up to 1 × 10 ⁻³ Pa.

FIG. 1 shows the changes over time in the value of the emission current Ie for Examples 1 and 2 and Comparative Examples 1 and 3.
The methane partial pressure is a: 1 × 10 ^-3 Pa, b: 1 × 10 ^-4 P
a, c: 1 × 10 ⁻⁵ Pa, d: 1 × 10 ⁻⁶ Pa, e: 2
× 10 ⁻⁷ Pa, f is without methane. Of these, a ~
d is measured by Example 2, e is measured by Comparative Example 3, and f is measured by the image forming apparatus manufactured by Comparative Example 1.

On the other hand, in Comparative Example 3, the methane pressure was set to 5 ×.
10 ^-3 Pa and the device, and the devices methane and helium gas is introduced total pressure 5 × 10 ^-3 Comparative Example 4 in which the Pa, the middle of raising the potential of the metal back for measurement, 1 kV Before reaching, the discharge occurred and it became impossible to display images. Other devices were operated by raising the anode potential to 5 kV as a trial, but no discharge occurred.

From the above results, as shown in FIG. 19, when the pressure of methane falls below 10 ^-6 Pa, the emission current Ie deteriorates rapidly, and therefore, the pressure of methane needs to be 10 ^-6 Pa or more. I understand. Also, the pressure of methane is 10 ^-4 P
It is particularly preferable that the value of a or more and 1 × 10 ⁻³ Pa or less causes almost no deterioration.

However, if the total pressure exceeds 1 × 10 ⁻³ Pa, discharge occurs and the anode voltage cannot be sufficiently increased, which is not preferable.

[Example 3] and [Comparative Example 5] The same steps as those in Example 1 were carried out. Without distinguishing between Example 3 and Comparative Example 5, instead of introducing methane, methane and hydrogen The pressure in the container was set to 1 × 10 ⁻⁴ Pa by introducing the mixed gas. The ratio of methane in the mixed gas of methane and hydrogen was varied in the range of 0.2 to 50% (molar ratio). From this result, the methane ratio is in the range of 1 to 50% (molar ratio) as Example 3, and the methane ratio is in the range of 0.2 to 1% (molar ratio) as Comparative Example 5.

The emission current value was measured in the same manner as in Example 1. When the values 1 hour after the start of measurement were compared, the results were as shown in FIG. 20 (100% is the value of Example 2). It can be seen from FIG. 20 that the emission current Ie sharply decreases when the methane ratio is less than 1%.

In the case where 1% or more of methane is contained,
That is, the partial pressure of methane is 1 × 10 ^-6When Pa or more
The emission current Ie does not decrease so much, but
5%, that is, the partial pressure of methane is 5 × 10^-Below 7 Pa
The deterioration became noticeable.

In this example, the ratio of methane was 50%.
(That is, the partial pressure of methane is 5 × 10 ⁻⁵ Pa) and the measurement result of Example 2 where the introduction pressure of methane is 5 × 10 ⁻⁵ Pa are compared. Comparing the electron emission efficiency, that is, the ratio of the emission current Ie to the device current If, [Ie / If], it is 0.10% in the second embodiment, but 0.12% in the third embodiment. It was It is speculated that in Example 2, the introduction of the organic substance gas into the vacuum container of the image forming apparatus formed a slight current path that did not contribute to electron emission. Example 3
Then, by introducing the hydrogen gas, the amount of hydrogen radicals in the atmosphere increases, and the etching action thereby increases, so that the path of the current that does not contribute to electron emission decreases,
It may have increased the electron emission efficiency.

[Example 4] and [Comparative Example 6] An image forming apparatus was used in the same manner as in Example 1, Example 2 and Comparative Example 3 except that ethylene C ₂ H ₄ having a double bond was used instead of methane. It was created. In Example 4, the partial pressure of ethylene was in the range of 1 × 10 ⁻⁶ Pa to 1 × 10 ⁻³ Pa, and in Comparative Example 6, the partial pressure of ethylene to be introduced was 2 × 10 6 as in Comparative Example 3. An image forming apparatus having a pressure of less than ^-7 Pa and a pressure of 5 × 10 ^-3 Pa or more was prepared.

As described above, the average residence time of ethylene is at most several tens of n to 100 nsec. It seems to be about 60
Driving cycle 16.7 msec. Much shorter than

When the same measurement was carried out, almost the same result was obtained. As in the case of methane, the effect was recognized when the partial pressure of ethylene was in the range of 1 × 10 ⁻⁶ Pa to 1 × 10 ⁻³ Pa. It was found that 1 × 10 ⁻⁴ Pa or more is particularly preferable.

[Example 5] The same procedure as in Example 1 was carried out except that acetylene C ₂ H ₂ having a triple bond was enclosed in 5 x 10 ^-5 Pa instead of methane. The average residence time τ of acetylene is at most several hundreds nsec. ~ 1μ
sec. It seems that the driving cycle is 16.7 msec. When driven at 60 Hz. Much shorter than

The result of the measurement had the effect of suppressing the deterioration as in the case of Example 1.

Example 6 A film was prepared in the same manner as in Example 1 except that C ₄ H ₂ having a triple bond was enclosed in place of methane. An attempt was made to measure the average residence time τ by the method described above, but the value of L was too small to effectively measure the value. This is because the value of the average stay time τ is msec. It seems that it is smaller than the order, so that the driving cycle when driving at 60 Hz is 16.7 msec. It was clear that it was shorter than.

The result of the measurement had the effect of suppressing the deterioration as in the case of Example 1.

[Example 7] In the activation step of Example 1, methane was introduced instead of n-hexane.
The pressure during this activation was 1300 Pa. As in Example 1, a pulse voltage having a peak value of 15V was applied.

After the activation step, the inside of the vacuum vessel was evacuated and the pressure was reduced to 1 × 10 ^-8 Pa or less as in Example 1. In this example, lowering the pressure to 1 × 10 ⁻⁶ Pa or less could be achieved in a relatively short time compared to the case where the activation step was performed using n-hexane. After this, a gas introduction step was performed. The gas introduced was methane, and the pressure was the same as that shown in Examples 1 and 2.

When the change of the emission current Ie due to driving was measured under the same conditions as in Examples 1 and 2, almost the same result was obtained.

[0139]

As described above, by enclosing a gas of an organic substance having an average residence time shorter than a driving cycle in a container of an image forming apparatus, deterioration of electron emission characteristics can be suppressed and an image can be formed. A characteristic preferable for use as a forming device, that is, an MI characteristic that is uniquely determined as described above with respect to the element voltage Vf for both the element current If and the emission current Ie,
Could be maintained. The partial pressure of organic substances is 1 × 10
^-6 Pa or more, particularly preferably 1 x 10 ^-4 Pa or more, and the total pressure in the vacuum container is 1 x 10 ^-3 Pa or less. Further, by enclosing hydrogen together with the gas of the organic substance, the electron emission characteristics are improved, which is more preferable.

[Brief description of drawings]

FIG. 1 is a diagram showing the effect of the present invention, showing changes over time in the amount of emission current for an example and a comparative example relating to the image forming apparatus of the present invention.

FIG. 2 is a schematic diagram for explaining a basic configuration of an electron-emitting device used in the present invention.

FIG. 3 is a schematic diagram showing an example (matrix wiring) of a wiring method in an electron source used in the present invention.

FIG. 4 is a schematic view (perspective view) showing an example of a configuration of an image forming apparatus of the present invention using an electron source of matrix wiring.

FIG. 5 is a schematic diagram showing a configuration of a fluorescent film used in the image forming apparatus of the present invention.

FIG. 6 is a schematic view showing an example of an apparatus for performing an activation step in the manufacturing process of the image forming apparatus of the present invention.

FIG. 7 is a schematic view showing wiring for a forming step of an electron source which is matrix-wired in the manufacturing process of the image forming apparatus of the present invention.

FIG. 8 is a schematic view showing another example of wiring (ladder type wiring) in the electron source used in the present invention.

FIG. 9 is a schematic view (perspective view) showing an example of the configuration of an image forming apparatus of the present invention using a ladder-type wiring electron source.

FIG. 10 is a schematic plan view showing a partial structure of an electron source of matrix wiring.

11 is a schematic view showing a structure of a cross section taken along line AA in FIG.

FIG. 12 is a schematic view for explaining the manufacturing process of the electron source of the matrix wiring used in the present invention.

FIG. 13 is a schematic diagram for explaining the manufacturing process of the electron source of the matrix wiring used in the present invention.

FIG. 14 is a schematic view showing an apparatus for stabilizing the gift forming apparatus of the present invention.

FIG. 15 is a schematic diagram showing a configuration of an apparatus for measuring an average staying time.

FIG. 16 is a diagram for explaining a method of stopping the average staying time based on the results obtained by the apparatus of FIG.

FIG. 17 is a view for explaining the waveform of the pulse voltage used in the forming step in the manufacturing process of the gift forming device of the present invention.

FIG. 18 shows the difference in emission current change between the image forming apparatus of the example of the present invention and the apparatus of the comparative example when the drive pulse application is interrupted and then reunited to explain the effect of the present invention. It is a schematic diagram.

FIG. 19 is a diagram showing the effect of the present invention, showing the relationship between the pressure of methane and the emission current value in the image forming apparatuses of the examples and the comparative examples of the present invention.

FIG. 20 shows a system between the ratio of methane in the mixed gas and the emission current value in the image forming apparatus of the embodiment and the comparative example of the present invention in which the mixed gas of hydrogen and methane is sealed, and shows the effect of the present invention. It is a figure.

FIG. 21 is a schematic diagram showing the relationship among the element voltage, the element current, and the emission current of the electron-emitting device that constitutes the image forming apparatus of the present invention.

[Explanation of symbols]

 1 Substrate 2, 3 Element Electrode 4 Conductive Film 5 Electron Emission Section 6 Deposit 31 Substrate 32 X Direction Wiring 33 Y Direction Wiring 34 Surface Conduction Electron Emission Element 35 Connection 41 Rear Plate 42 Support Frame 43 Glass Substrate 44 Fluorescent Film 45 Metal back 46 Face plate 47 Vacuum container 51 Black conductive material 52 Phosphor 61 Image forming device 62 Exhaust pipe 63 Vacuum chamber 64 Gate valve 65 Exhaust device 66 Pressure gauge 67 Quadrupole mass analyzer 68 Gas introduction line 69 Introduction control means 71 Common Electrode 81 Substrate 82 Electron Emitting Element 83 Common Wiring 91 Grid Electrode 92 Void 93 Outer Container Terminal 94 Outer Container Terminal 95 Substrate 102 X Direction Wiring 103 Y Direction Wiring 104 Interlayer Insulation Layer 105 Contact Hole 106 Cr Film 107 Conductive Film 131 Heater 132 exhaust 141,142 vacuum vessel 143 gate valve 144 thin tube 145 pressure gauge 610 introduced substance source

Claims (9)

[Claims] 1. A pair of device electrodes facing each other on a substrate,
It has a conductive film connected to the pair of device electrodes and an electron emitting portion formed in a part of the conductive film, and further has carbon or a carbon compound as a main component in the electron emitting portion and its vicinity. An image forming apparatus in which an electron source including an electron-emitting device having a coating and an image forming member that forms an image by irradiation of an electron beam emitted from the electron source are included in a vacuum container, Is filled with a gas of an organic substance, the partial pressure of the gas of the organic substance is 1 × 10 ⁻⁶ Pa or more, and the total pressure in the vacuum container containing the organic substance is 1 × 10 ⁻³ Pa or less. And an average residence time of the molecules of the organic substance is shorter than a driving cycle of the electron source. 2. The partial pressure of the gas of the organic substance is 1 × 10.
The image forming apparatus according to claim 1, wherein the image forming apparatus has a ^{pressure of −4} Pa or more. 3. The image forming apparatus according to claim 1, wherein the vacuum container is filled with hydrogen gas together with the gas of the organic substance. 4. The organic substance is CH ₄ (methane), C ₂ H
The image forming apparatus according to claim 1, wherein the image forming apparatus is any one of ₄ (ethylene), C ₂ H ₂ (acetylene), and C ₄ H ₂ (butadiene). 5. A pair of device electrodes facing each other on a substrate,
It has a conductive film connected to the pair of device electrodes and an electron emitting portion formed in a part of the conductive film, and further contains carbon or a carbon compound as a main component in the electron emitting portion and its vicinity. A method of manufacturing an image forming apparatus, comprising: an electron source including an electron-emitting device having a coating; and an image forming member that forms an image by irradiation of an electron beam emitted from the electron source, in a vacuum container. A forming step of forming the electron emitting portion, introducing a gas of an organic substance into the vacuum container, applying a pulse voltage to the electron emitting device, and mainly applying carbon or a carbon compound to the electron emitting portion and its vicinity. An activation step of depositing a coating film as a component, a stabilization step of removing the organic substance in the vacuum container after the activation step, an organic substance having an average residence time shorter than the driving period of the electron-emitting device, or And a gas introduction step of introducing a mixed gas of the organic substance and hydrogen gas into a vacuum container. 6. The partial pressure of the organic material having an average residence time longer than the driving cycle of the device in the stabilizing step is 1.
The method for manufacturing an image forming apparatus according to claim 5, wherein the pressure is less than 0 × 10 ⁻⁶ Pa. 7. The vacuum container in the stabilizing step
Pressure is 1.0 × 10 ^-6To be less than Pa
The method according to claim 5, wherein the image forming apparatus is manufactured. 8. The organic material introduced into the vacuum container in the activation step is the same as the organic material introduced in the gas introduction step.
8. The method for manufacturing an image forming apparatus according to any one of 7 to 7. 9. The organic substance having an average residence time shorter than the driving cycle of the electron-emitting device is CH ₄ (methane), C ₂ H.
9. The method of manufacturing an image forming apparatus according to claim 5, wherein the method is any one of ₄ (ethylene), C ₂ H ₂ (acetylene), and C ₄ H ₂ (butadiene).