JPH10241550A - Electron source formation substrate, electron source, image forming device and their manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the adverse effect of the diffusion of sodium into a conductive film composed of an electron emission element by setting the sodium content of at least a surface layer region for arranging the electron emission element to be smaller than those of the other regions in a substrate containing sodium for arranging the electron emission element. SOLUTION: An Na removed layer, an Na captured layer or the stacked layer structure of both or a surface treated layer 6 such as a desulfurized layer are formed in the surface of a blue glass substrate 1, and then element electrodes 2 and 3 are formed. A conductive film 4 is formed to cover the element electrodes 2 and 3 and the surface of the surface-treated layer 6. Then, an electron emission part 5 is constructed to have a changed structure where the conductive film 4 is locally broken, deformed or transformed by conductive forming. Thus, variance in the characteristics of the electron emission element or the deterioration of characteristics is suppressed, and the electron emission element is formed by using the blue glass substrate 1 excellent in machining such as joining and advantageous in costs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron-emitting device having a pair of device electrodes provided to face each other, and a conductive film connected to the pair of device electrodes and having an electron-emitting portion in a part thereof. The present invention relates to an electron source having a plurality of substrates arranged on one or more substrates, a method of manufacturing the same, an image forming apparatus and a method of manufacturing the same using the electron source, and a substrate for forming an electron source used for forming the electron source.

[0002]

2. Description of the Related Art Heretofore, two types of electron-emitting devices, a thermionic electron-emitting device and a cold cathode electron-emitting device, are known. The cold cathode electron emitting 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 emitting device, and the like. As an example of the FE type, W. P. Dyke &
W. W. Dolan, "Field emissio
n ", Advance in Electron Phy
sics, 8, 89 (1956) or C.I. A. Sp
indt, “PHYSICAL Properties
of thin-film field emiss
ion cathodes with mollybde
num cones ", J. Appl. Phys., 4
7, 5248 (1976) and the like are known.

As an example of the MIM type, C.I. A. Mead,
“Operation of Tunnel-Emis
site Devices, ”J. Apply. Phys.
s. , 32, 646 (1961).

Examples of the surface conduction electron-emitting device type include:
M. I. Elinson, Recio Eng. Ele
ctron Phys. , 10, 1290, (196
5) and the like.

[0005] The surface conduction electron-emitting device utilizes a phenomenon in which an electron is emitted when a current flows in a small-area thin film formed on a substrate in parallel with the film surface. Examples of the surface conduction electron-emitting device include a device using a SnO ₂ thin film by Ellison and the like and a device using an Au thin film [G. Dittmer: “Thin Solid Fi
lme "9,317 (1972)], In 2 O 3 / SnO
₂ Thin film [M. Hartwell and
C. G. FIG. Fonstad: "IEEE Trans. E
D Conf. 519 (1975)], using a carbon film [Hisashi Araki et al .: Vacuum, Vol. 26, No. 1, 2
2 (1983)].

[0006] Regarding the further improvement of the surface conduction electron-emitting device, many proposals have been made by the present applicant.

FIGS. 20A and 20B schematically show a typical configuration of the above-mentioned surface conduction electron-emitting device. FIG. 209A is a plan view, and B is a cross-sectional view. Reference numeral 1 denotes a base, reference numerals 2 and 3 denote a pair of element electrodes provided on the base so as to face each other, and reference numeral 4 denotes a conductive film connected to the above-mentioned element electrodes 2 and 3, and a part thereof has an electron emission portion. Conventionally, the formation of the electron emitting portion is performed by using the conductive film 4.
In general, it is formed by an energization process called energization forming. That is, the energization forming means that a voltage is applied between the pair of element electrodes 2 and 3 to which the conductive film 4 is connected to flow a current through the conductive film, and the conductive film is locally destroyed, deformed, or deformed. The purpose is to form the electron-emitting portion 5 that has been altered and is in an electrically high-resistance state.
In the electron emitting portion 5, a crack is generated in a part of the conductive film 4, and electrons are emitted from the vicinity of the crack. The voltage applied during the energization forming process may be a DC voltage or a voltage that rises slowly, but it is preferable to repeatedly apply a pulse voltage in order to obtain good electron emission characteristics. Various methods such as a method of maintaining the peak value of the pulse voltage constant or a method of gradually increasing the pulse voltage may be employed depending on conditions.

[0008] In order to form an electron-emitting portion so as to exhibit preferable electron-emitting characteristics by the energization forming process, the conductive film is desirably formed of conductive fine particles. The method for forming a conductive film composed of the conductive fine particles as described above is not particularly limited, but after applying a solution containing an organic metal compound to form a film of the organic metal compound, and then heating the film. Process,
A method of forming a conductive film comprising fine particles of a metal and / or a metal compound may be used. According to this method, a large-sized vacuum device is not required unlike the gas deposition method, and thus it is desirable from the viewpoint of reduction in production cost. In addition, when a method of applying a vapor solution to only a portion where a film is formed using an ink jet device is used, there is no need to provide another step for patterning a conductive film, and the same advantage is obtained.

As a material of the conductive film, fine particles of PdO formed by heat-treating an organic compound of Pd in the air can be exemplified. This heat treatment is 300
It is typically performed at about 400 ° C. for about ten minutes. Pd
O has appropriate conductivity, and can form an electron-emitting portion by the above-described energization forming process successfully.
Further, PdO can be relatively easily reduced to Pd by heating it in a vacuum or exposing it to a reducing gas. After the formation of the electron-emitting portion by the energization forming process is completed, PdO is reduced to Pd
By doing so, the resistance value of the conductive film can be reduced by about two digits. Once the electron-emitting portion is formed, lowering the resistance of the conductive film may be preferable for the characteristics of the device, and in such a case, the above-described method can be used.

An electron source constituted by arranging a plurality of electron-emitting devices having the above-mentioned configuration on a substrate and an image forming apparatus using the same are also shown in the above description. In order to use the electron source while holding it in an envelope whose inside is kept in a vacuum, it is necessary to join the electron source with the envelope and other members. This joining is generally performed by heating and fusing with frit glass. The heating temperature at this time is typically about 400 to 500 ° C.,
The time varies depending on the size of the envelope, but 10 minutes to 1
Time is typical.

As the material of the envelope, it is preferable to use soda-lime glass from the viewpoint that bonding with frit glass is easy and reliable. Blue sheet glass is also preferable in that it is relatively inexpensive. As the material of the base, it is necessary to match the thermal expansion coefficient with the envelope,
Similarly, it is desirable to use soda-lime glass from the viewpoint of the reliability of joining the base itself to the envelope.

[0012]

However, when the blue plate glass is used as the base as described above, the following problems may occur.

That is, the soda lime glass contains a large amount of an alkali metal element, particularly Na, as a component as Na ₂ O. Since the Na element is easily diffused by heat, if it is exposed to a high temperature in the process, Na may diffuse into various members formed on the soda lime glass, in particular, into a conductive film, and may change its characteristics.

As described above, when a metal oxide fine particle film is formed by heat-treating an organometallic compound, it is kept at a temperature of, for example, 300 to 400 ° C. for about ten minutes. At this time, Na in the substrate may diffuse into the conductive film.

In the case where the conductive film is made of a conductive metal oxide such as PdO, a reduction treatment may be performed after the formation of the electron-emitting portion by the forming treatment as described above to reduce the electric resistance. However, if a large amount of Na is present in the PdO film, the speed of the reduction reaction may be reduced.
Since the extent to which the reaction rate is slowed changes sensitively according to the amount of Na, it becomes difficult to uniformly uniform the characteristics of many electron-emitting devices. According to preliminary studies, the Na content is 1000 p.m. at the mole ratio of the metal element in the PdO film.
p. m. In the following cases, it was confirmed that the reduction in the reduction rate was not so significant, but that the reduction time began to increase sharply beyond this point. FIG. 21 shows that H ₂ : 2% -N
₂ : Changes in electrical resistance of the conductive film when exposed to a 98% mixed gas and reduced.

The content of Na in the conductive film is set to 1000 p. p. m. In order to make the following, by preliminary examination, all the metal elements (hereinafter, for convenience, when the components of the substrate are described, Na, K, Ca, In addition to Mg and the like, Si and P are also called "metal elements."
a is 2 at. %.
The above-mentioned content of Na on the substrate surface is a value obtained from a secondary ion mass spectrometry (SIMS) measurement by a method described later, and is an amount up to a depth of about 5 nm from the surface.

In addition, the influence on the reduction treatment may be affected not only by Na but also by S contained in the substrate. The mechanism by which S affects the reduction treatment is not well understood, but the following mechanism may be considered. When S enters PdO, PdS is formed, and remains almost unreduced by the reduction treatment. But,
The amount of S contained in the substrate is insignificant, and this alone cannot explain the effect on the reduction reaction. Isn't PdS that is hard to be reduced formed on the surface of the PdO fine particles that form the conductive film, which prevents the progress of the reduction reaction?

In any case, if S is contained in the substrate, even a small amount thereof may have some influence, and it is desirable to reduce S near the surface of the substrate as much as possible. It is desirable that the temperature be below the detection limit by simple measurement. Specifically, it is a comparatively simple and quantitative X-ray photoelectron spectroscopy in ordinary measurement, and the detection limit is 0.1 at. % (This value is a ratio to all atoms in a region up to a depth of 5 nm).

In any case, if the reduction is different for each device, the voltage applied to the electron-emitting portion of each device is different when electrons are emitted, which is also a factor of the variation in the electron emission characteristics. Becomes Also, the reduction is incomplete,
When the resistance value of the conductive film is high, the value of the emission current may decrease.

When a substrate of an electron source, a member of an envelope, and the like are fused and joined using frit glass, the substrate is further exposed to a high temperature, so that the amount of Na (and S) diffused into the conductive film. Will increase significantly, and the situation will become even more serious.

However, it is necessary to avoid using a material other than blue plate glass such as quartz for the substrate, because the material itself is expensive and processing such as bonding becomes difficult.

One of the methods used for this purpose is to apply SiN (Japanese Patent Laid-Open No. 8-16200) on the surface of a blue glass substrate.
1) Alternatively, an SiO ₂ film is formed by a method such as sputtering. However, in this method, stress is generated between the soda lime glass substrate and the SiN or SiO ₂ film, and if the SiN or SiO ₂ is too thick, it is peeled off. Therefore, the thickness is limited. When the time is long, a sufficient effect cannot be obtained. Further, a sputtering apparatus is required for forming a film, and a considerably large apparatus is required for the size of the substrate, which causes an increase in manufacturing cost.

Therefore, regardless of such a method, the above N
There is a need for a method of avoiding the adverse effects of diffusion of a and S into a conductive film or the like.

[0024]

The configuration of the present invention made to solve the above problem will be described below.

According to the present invention, there is provided a substrate having an electron-emitting device disposed on a surface thereof, wherein the substrate is a substrate containing sodium, and at least a side of the substrate on which the electron-emitting device is disposed. The concentration of sodium in the surface region is
A substrate characterized by being smaller than the other region, comprising: a substrate; and an electron source having an electron-emitting device disposed on the surface of the substrate, wherein the substrate comprises a substrate containing sodium. Wherein the concentration of sodium in at least the surface region of the substrate on the side where the electron-emitting devices are arranged is smaller than that of the other region, wherein the substrate and the substrate An image forming apparatus comprising: an electron source having an electron emission element disposed on a surface; and an image forming member that forms an image by irradiating electrons from the electron source. An image forming apparatus, comprising: a substrate; and an electron-emitting device having an electron-emitting device disposed on a surface of the substrate. The element is placed Wherein the concentration of the sodium in the surface region on the side is smaller than in the other region, the method comprising the step of forming the electron-emitting device on the surface of the substrate, A method for manufacturing an image forming apparatus, comprising: an electron source having a substrate and an electron-emitting device disposed on a surface of the substrate; and an image forming member that forms an image by irradiating electrons from the electron source, An image forming apparatus, wherein the electron source is manufactured by the method of the present invention.

According to the present invention, there is provided an electron emitting device having one or a plurality of electron-emitting devices on a substrate, each of which comprises a pair of opposing device electrodes and a conductive film connected to the device electrodes and including an electron-emitting portion. The present invention relates to an electron source, an image forming apparatus using the same, and a method for manufacturing the same, particularly having a feature in the base of the electron source. That is, the main body of the substrate is made of a glass containing Na suitable for processing such as bonding, for example, a so-called “blue sheet glass”, and there are many kinds of compositions thereof. The above-mentioned blue sheet glass is generally composed of SiO ₂ : 69-7
5%, Na ₂ O: 10 to 17%, and K ₂ O, Ca
It contains O, MgO and the like.

The configuration of the electron source and the image forming apparatus according to the present invention is characterized in that at least the surface of the substrate on which the electron-emitting devices are provided, the region where the electron-emitting devices are provided has a Na concentration. Has a distribution in the depth direction, and the Na concentration on the surface is lower than the Na concentration in a region where the Na concentration inside the substrate is constant.

Next, the features of the manufacturing method for realizing the above-mentioned electron source and image forming apparatus of the present invention will be described. In the first embodiment of the present invention, the substrate used for the production has, in the initial state, a region having a reduced Na content (de-Na-treated layer) on its surface. The ratio of Na to metal element is 2a
t. % Or less.

The necessary thickness d of this layer is determined as a function of the heat treatment temperature T (K) and the heat treatment time t (sec.) To which the substrate is exposed in the process of forming the electron source or the image forming apparatus. Even if the content of Na at the interface between the Na removal layer on the substrate surface and the conductive film increases due to diffusion of 2 at. %.

Although this can be obtained by experiments, an approximate value can be estimated from a one-dimensional diffusion model. That is, the concentration of Na in the base body is C ₈ , the concentration of Na at the interface between the Na removal treatment layer and the conductive film is C,
The thickness of the treatment layer is d, the diffusion coefficient of Na in the Na removal layer is D, and Na is substantially not present in the Na removal layer, and the vicinity of the interface between the base body and the Na removal layer is Simplified assuming that the Na concentration in is unchanged, the following relationship holds: C / Cs = erfc [d / {2 (Dt) ^1/2 }] (1) Here, erfc (x) is a complementary error function (er
error function), and an error function (err function) er
f (x) has a relationship of erfc (x) = 1−erf (x) (2). The error function erf (x) is

[0031]

(Equation 1) Is defined by When the concentration is not so high, the above diffusion coefficient D is represented by D = D ₀ exp [−Ea / kT] (4) regardless of the concentration. D ₀ is a constant, Ea is the activation energy, k
Is the Boltzmann constant (（1.38 × 10 ^23. The diffusion coefficient in SiO ₂ is 1.0 × 10 ⁻²¹ at room temperature.
(Cm ^{2 /} sec.) At 450 ° C. (723 K) 6.1
A value of about × 10 ⁻⁹ (cm ² / sec) was obtained, from which Ea = 1.7 × 10 ⁻¹⁹ (J) and D ₀ = 1.
It is required to be about 1 × 10 ⁻¹ (cm ² / sec.). These are used to remove Na which can withstand the heat treatment process.
The thickness of the treatment layer can be estimated.

Actually, when Na diffuses from the base body into the Na-removed layer, the amount of Na at the interface decreases. Therefore, even if the thickness can be expected to be slightly smaller than the thickness obtained from the above model, There is also.

As described above, N on the surface of the Na-removed layer is
a is 2 at. % Or less, it is necessary to decrease to about 1/10 to 1/15 compared to the inside of the substrate. According to the above-mentioned formula (1), the above-mentioned (Dt) It can be seen that it is sufficient to be about 2.4 times ^1/2 .

For example, if the step of heat-treating an organometallic compound to form a conductive film is a heat treatment at 350 ° C. for 10 minutes, the diffusion coefficient is D = 2.9 from the above activation energy value. × 10 ⁻¹⁰ (cm ² / sec.), And a thickness of about 10 μm is required. Further, a high-temperature treatment is necessary for joining the base and the member of the envelope. For example, when heat treatment is performed at 450 ° C. for 10 minutes, about 50 ° C.
A thickness of μm is required.

The conditions for the Na-removed layer are set by the above-described formulas in consideration of the conditions for forming the electron source and the image forming apparatus of the present invention. There are various compositions of blue sheet glass that can be used as a substrate, but the ratio of Na to all metal elements, that is, Cs in the formula (1) is 20 at. %. The value shown above as the coefficient D _{0 in} equation (4) is for a densely formed SiO ₂ , which may be larger in an actual substrate, and is at most twice the above value. About. The heating temperature when the conductive film is formed by thermal decomposition of the organometallic compound needs to be higher than the decomposition temperature of the organometallic compound. P as conductive film
When d or PdO or a mixture of both is used, 250 ° C. or higher is required for the organic Pd compound to decompose into metal Pd, depending on the type of the compound. Further, although depending on the atmosphere at the time of heating, it is necessary to further raise the temperature in order for Pd to be oxidized to PdO. The time required for this process is about 5 to 20 minutes. Under the above conditions, the thickness of the Na removal layer required to cope with the heat treatment for forming the conductive film is in the range of 1 to 40 μm depending on the conditions.

When various members are joined to form an image forming apparatus using the electron source of the present invention, when frit glass is used for joining, a temperature of 400 to 500 ° C.
Is performed. The time required for the treatment is about 10 to 20 minutes. In consideration of this condition, the thickness of the Na-removed layer required from the formula (1) is 20 to 140 μm. Of course, if a thicker treatment layer is formed, the problem caused by Na can be dealt with. However, if this layer is too thick, it may have some adverse effect. It is desirable that the thickness be as small as possible.
In addition, for the joining of the members of the image forming apparatus, frit glass that can be joined by a heat treatment at a temperature lower than the above-described temperature may be used. In that case, the thickness of the Na removal layer may be smaller. The value is not limited to the above value.

The above-mentioned Na removal layer is effective if it is located at the portion where the conductive film of the electron-emitting device is to be formed. The effect of suppressing the change in the characteristics of the material can be expected. On the other hand, in the part to be joined with the member of the envelope, the composition containing Na ₂ O has a better adhesiveness to the frit glass as in the case of the base body. Is more preferred. As described above, in order not to provide the Na removal layer in a part, the Na removal processing may be performed by covering the part with a mask or the like.

As a method of removing Na, taking advantage of the fact that Na easily moves in the glass, by precipitating it as a sulfate on the surface of the substrate, Na ions near the surface are taken out to the outside, and this is extracted with water or the like. A washing method is preferably used. As a method of precipitating it as a sulfate on the surface of the substrate, a method of maintaining the temperature at a high temperature in an atmosphere containing sulfur dioxide SO ₂ , a method of placing ammonium ammonium on the surface of the substrate and maintaining the temperature at a high temperature can be used.

The precipitated sodium sulfate can be washed with water. After the washing, water is contained on the surface of the Na-removed layer, so that it is desirable to perform a drying step. At this time, if the temperature is too high, Na inside the substrate diffuses again into the Na-removed layer, so that an appropriate temperature is set, for example, about 120 ° C.

A feature of the second embodiment of the present invention resides in that a Na trapping layer is formed on the surface of the base made of the above-mentioned soda lime glass. The Na capture layer is a layer made of a material that suppresses the diffusion of Na ions.
Glass containing iO ₂ as a main component and containing about 3 to 10% of phosphorus (P), or glass obtained by replacing Na in blue plate glass with K is exemplified. By providing a layer of such a material, it is possible to prevent Na in the blue plate glass from entering a member such as the conductive film of the electron-emitting device and changing its characteristics. Specific examples of the method for forming the Na capture layer include a thin film deposition method such as a chemical vapor deposition (CVD) method, and a method in which a soda lime glass is immersed in a molten potassium salt to perform ion exchange between Na and K. .

As compared with the method of the first embodiment, N
Since the diffusion rate of a is slow, the effect can be expected even if the Na capture layer is relatively thin.

As in the case of the first embodiment, the joining member with the member of the envelope or the like does not form a Na trapping layer, and the frit glass and the soda-lime glass are in direct contact with each other. Is preferred.

Note that the first embodiment and the second embodiment can be used in combination.

The distribution of the Na concentration in the depth direction in the region where the electron-emitting device is formed on the electron source and the substrate of the image forming apparatus formed by the above-described method is, for example, secondary ion mass spectroscopy (SIMA). Can be measured using FIG. 21 schematically shows the result.

The Na concentration profile of the layer having a low Na concentration, ie, the Na-depleted layer and the Na trapping layer formed on the above-described substrate was completed as an electron source or an image forming apparatus using the same through the above-described heat treatment. At that point, it is not the original.

The curve c in FIG. 21 indicates the above-mentioned Na removal layer.
5 shows a Na concentration profile immediately after a Na capture layer is formed. In the electron source or the image forming apparatus formed by the method of the present invention, the above Na concentration changes as shown by a curve a. In other words, the value is constant inside the substrate, which coincides with the value of the glass before the above-described layer having a reduced Na concentration is provided, and the value is smaller near the surface of the substrate than the value inside. Further, the depth at which the Na concentration reaches the value inside the substrate depends on the thickness d of the initially formed low-Na concentration layer.
Almost matched. In the figure, this depth is indicated by d '.

On the other hand, when the layer having a low Na concentration was not provided, or when the thickness was insufficient for the heat treatment conditions during the production, as shown by the curve b,
It was found that the Na concentration on the substrate surface was higher than the internal value. This is because N
This is probably because a diffused and segregated near the surface. In the curve a, the Na concentration slightly increases near the surface, and in the curve b, the Na concentration slightly decreases. However, this is not essential due to contamination and the effect of cleaning during measurement. . Therefore, the measurement was performed by regarding the value of the peak slightly below the surface that was not affected by contamination or the like as indicated by Csa or Csb as the Na concentration on the surface.

When the concentration of Na on the surface of the substrate is lower than that on the inside, there is some effect for suppressing the adverse effect of Na, but the concentration near the surface indicates that the ratio of Na to the total metal elements is If it is less than 2%, a remarkable effect is expected.

A third embodiment of the present invention is to provide a desulfurization treatment layer on the basic surface. Slightly in some cases, S may be contained in the blue plate glass, and when S enters the conductive film, the speed of the reduction treatment may be slow or the treatment may be incomplete. It should be noted that S is not generated only from the substrate, but is caused by various factors during the process.
Contamination may occur. For this reason, desulfurization treatment may be performed at each stage of the process as needed, but it is necessary to treat S in the substrate first. In some cases, S is removed simultaneously by the above-described Na removal treatment. In this case, the effect of the desulfurization treatment is obtained simultaneously with the effect of the Na removal treatment. However, in some cases, a further effect may be obtained by separately performing desulfurization treatment. The S concentration of the desulfurization treatment layer is 0.1
at. % Or less, and the thickness is desirably 0.01 μm or more. In addition, the adverse effect of S is caused by the fact that the substrate
It may occur even if it is not a blue plate glass containing much a,
The effect of this treatment is not limited to the case of soda lime glass.

[0050]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electron-emitting device to which the present invention is applied and a method for manufacturing the same will be described. Figures 1A and 1B
1 schematically shows the structure of the electron-emitting device of the present invention. FIG. 1A
Is a plan view and FIG. 1B is a sectional view. 1 is a main body of a base made of soda lime glass, 2 and 3 are device electrodes, 4 is a conductive film, 5
Denotes an electron emission portion. 6 is a Na removal layer, a Na capture layer,
Alternatively, it shows a laminated structure of both, or a desulfurization treatment layer.

FIG. 2 schematically shows another example of the structure of the electron-emitting device to which the present invention is applied. 21 is a step forming member,
The electron emission portion 5 is formed on the side surface of the step forming member. As the material of the step forming member, a material having sufficiently small contents of Na and S, such as a SiO ₂ film formed by a sputtering method, is used.

As a material for the device electrodes 2 and 3, a general conductor material can be used. This is, for example, Ni, C
metals or alloys such as r, Au, Mo, W, Pt, Ti, Al, Cu, Pd and Pd, Ag, Au, RuO ₂ , Pd −
The material can be appropriately selected from a printed conductor made of a metal such as Ag or a metal oxide and glass, a transparent conductor such as In ₂ O ₃ —SnO ₂ , and a semiconductor conductor material such as polysilicon.

The element electrode interval L, the element electrode length W, the shape of the conductive film 4 and the like are designed in consideration of the applied form and the like. The element electrode interval L is preferably in the range of several hundred nm to several hundred μm, more preferably several μm.
To several tens of μm.

The length W of the device electrode can be in the range of several μm to several hundred μm in consideration of the resistance value of the electrode and the electron emission characteristics. The film thickness of the device electrodes 2 and 3 can be in the range of several tens nm to several μm.

In addition to the structure shown in FIGS. 1 and 2, the conductive film 4 and the opposing element electrodes 2 and 3 are arranged in this order on the surface treatment layer 6 of the substrate 1 (or on the step forming member 21). A stacked configuration can also be used.

As the conductive film 4, it is preferable to use a fine particle film composed of fine particles in order to obtain good electron emission characteristics. The film thickness is appropriately set in consideration of the step coverage for the device electrodes 2 and 3, the resistance value between the device electrodes 2 and 3, a forming condition described later, and the like.
It is preferably in the range of several times 0.1 nm to several hundred nm, more preferably in the range of 1 nm to 50 nm. The resistance value is such that Rs is 10 ² to 10 ⁷ Ω / □. Rs is the resistance R measured in the length direction of a thin film having a thickness t, a width w, and a length of 1, and R = Rs (1 /
Assuming that the resistivity of the thin film is ρ in the amount that appears when w), Rs = ρ / t. In the specification of the present application, the forming process will be described by taking an energizing process as an example, but the forming process is not limited to this, and includes a process of forming a crack in a film to form a high resistance state. It is.

The material constituting the conductive film 4 is Pd, P
t, Ru, Ag, Au, Ti, In, Cu, Cr, F
metals such as e, Zn, Sn, Ta, W, Pd, PdO, S
It is appropriately selected from oxides such as nO ₂ , In ₂ O ₃ , PbO, and Sb ₂ O ₃ .

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

There are various methods for manufacturing the above-mentioned electron-emitting device, one example of which is schematically shown in FIG.

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

1) After the surface treatment layer 6 is formed on the surface of the base 1 made of soda lime glass, it is sufficiently washed with a detergent, pure water, an organic solvent or the like, and the device electrode is formed by a vacuum evaporation method, a sputtering method or the like. After depositing the material, the device electrodes 2 and 3 are formed using, for example, a photolithography technique. Alternatively, an appropriate printing material is arranged in a predetermined shape by offset printing or screen printing, and heat treatment is performed to form element electrodes 2 and 3. (FIG. 3 (a)).

2) Surface treatment layer 6 provided with device electrodes 2 and 3
An organic metal solution is applied thereon to form an organic metal thin film. As the organic metal solution, a solution of an organic metal compound containing the main metal element constituting the conductive film 4 as a main element can be used. The organic metal thin film is heated and baked, and is patterned by lift-off, etching, or the like to form a conductive film 4 (FIG. 3B). Here, the method of applying the organometallic solution has been described, but the method of forming the conductive film 4 is not limited to this, and a vacuum deposition method, a sputtering method, a chemical vapor deposition method, a dispersion coating method, A dipping method, a spinner method, or the like can also be used.

3) Subsequently, a forming step is performed.
As an example of a method of the forming step, a method by an energization process will be described. When current is applied between the device electrodes 2 and 3 using a power supply (not shown), an electron-emitting portion 5 having a changed structure is formed at the portion of the conductive film 4 (FIG. 3C). According to the energization forming, a portion of the conductive film 4 where a structure such as destruction, deformation or alteration is locally changed is formed.
This portion constitutes the electron emission section 5. FIG. 4 shows an example of the voltage waveform of the energization forming.

The voltage waveform is preferably a pulse waveform. This includes the method shown in FIG. 4A in which a pulse having a constant pulse peak value is applied continuously and the method shown in FIG. 4B in which a voltage pulse is applied while increasing the pulse peak value.

T1 and T2 in FIG. 4A are the pulse width and pulse interval of the voltage waveform. Normally, T1 is 1 μsec.
-10 msec. , T2 is 10 μsec. ~ 10ms
ec. Is set in the range. The peak value of the triangular wave (peak voltage at the time of energization forming) is appropriately selected according to the electron emission element form. Under such conditions, for example, a voltage is applied for several seconds to several tens minutes. The pulse waveform is not limited to a triangular wave, and a desired waveform such as a short waveform can be adopted.

T1 and T2 in FIG. 4B can be the same as those shown in FIG. 4A. The peak value of the triangular wave (peak voltage during energization forming) is, for example, 0.1
It can be increased by about V steps.

The completion of the energization forming process can be detected by locally destroying the conductive film 4 during the pulse interval T2, applying a voltage approximately equal to the deformation, and measuring the current. For example, an element current flowing by applying a voltage of about 0.1 V is measured, and a resistance value is obtained. When a resistance of IMΩ or more is indicated, the energization forming is terminated.

4) It is preferable to perform a process called an activation step on the element after the forming. The activation step means that the element current If and the emission current Ie are
This is a process that changes significantly.

The activation step can be performed, for example, by repeating the application of a pulse in an atmosphere containing a gas of an organic substance, similarly to the energization forming. This atmosphere can be formed by using an organic gas remaining in the atmosphere when the inside of the vacuum vessel is evacuated using, for example, an oil diffusion pump or a rotary pump, or is sufficiently evacuated once by an ion pump or the like. It can also be obtained by introducing a gas of an appropriate organic substance into a vacuum. The preferable gas pressure of the organic material at this time varies depending on the above-described application form, the shape of the vacuum vessel, the type of the organic material, and the like, and is appropriately set according to the case. Suitable organic materials include organic acids such as aliphatic hydrocarbons of alkane, alkene, and alkyne, aromatic hydrocarbons, alcohols, aldehydes, ketones, amines, phenols, carboxylic acids, sulfonic acids, and the like. Specifically, saturated hydrocarbons represented by C _n H _{2n + 2} such as methane, ethane and propane, unsaturated hydrocarbons represented by a composition formula such as C _n H _2n such as ethylene and propylene, benzene , Toluene, methanol, ethanol, harmaldehyde, acetaldehyde, acetone, methyl ethyl ketone, methylamine, phenol, formic acid, acetic acid, propionic acid and the like, or a mixture thereof. By this treatment, carbon or a carbon compound is deposited on the device from organic substances existing in the atmosphere, and the device current If and the emission current Ie change remarkably.

The termination of the activation step is appropriately determined while measuring the device current If and the emission current Ie. The pulse width, pulse interval, pulse crest value, and the like are set as appropriate.

The carbon and the carbon compound include, for example, graphite (HOPG, PG and GC containing HO,
PG refers to a crystal structure of almost perfect graphite, PG refers to a crystal grain of about 20 nm and has a slightly disordered crystal structure, and GC refers to a crystal grain of about 2 nm and has a further disordered crystal structure. ), Amorphous carbon (refers to amorphous carbon and a mixture of amorphous carbon and the microcrystals of graphite), and has a film pressure of 5
The range is preferably 0 nm or less, more preferably 30 nm or less.

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

In the activation step, when an oil diffusion pump or a rotary pump is used as an exhaust device and an organic gas derived from an oil component generated from the oil diffusion pump or the rotary pump is used, the partial pressure of this component must be kept as low as possible. . The partial pressure of the organic component in the vacuum chamber is preferably 1.3 × 10 ^-6 Pa or less at a partial pressure of carbon and carbon compounds described above do not substantially newly deposited, more is 1.3 × 10 ^-6 Pa or less Particularly preferred.
Further, when the inside of the vacuum vessel is evacuated, it is preferable to heat the entire vacuum vessel so that the organic material molecules adsorbed on the inner wall of the vacuum vessel and the electron-emitting device can be easily evacuated. The heating condition at this time is desirably 80 to 250 ° C., preferably 150 ° C. or higher, and it is desirable to perform the treatment for as long as possible. However, the present invention is not particularly limited to this condition, and the size and shape of the vacuum vessel,
This is performed under conditions appropriately selected according to various conditions such as the configuration of the electron-emitting device. The pressure in the vacuum vessel needs to be as low as possible, preferably 1 × 10 ⁻⁶ Pa or less, and more preferably 1.3 × 10 ⁻⁶ Pa
× 10 ⁻⁶ Pa or less is particularly preferred.

It is preferable that the atmosphere at the time of driving after the stabilization step is performed is the same as that at the end of the stabilization treatment, but the present invention is not limited to this. Even if the degree of vacuum itself is slightly reduced, sufficiently stable characteristics can be maintained.

By adopting such a vacuum atmosphere, the deposition of new carbon or carbon compound can be suppressed.
Further, H ₂ O, O ₂ , and the like adsorbed on a vacuum vessel, a substrate, and the like can be removed, and as a result, the element current If and the emission current Ie are stabilized.

The basic characteristics of the electron-emitting device to which the present invention can be applied obtained through the above-described steps will be described with reference to FIGS.

FIG. 5 is a schematic view showing an example of a vacuum cormorant processing apparatus. This vacuum processing apparatus also has a function as a measuring and evaluating apparatus. In FIG. 5 as well, the same parts as those shown in FIG. In FIG. 5, 55 is a vacuum vessel, and 56 is an exhaust device. An electron-emitting device is provided in the vacuum vessel 55. 51 is a power supply for applying a device voltage Vf to the electron-emitting device, 50 is an ammeter for measuring a device current If flowing through the conductive film 4 between the device electrodes 2 and 3, and 54 is an electron-emitting portion of the device. This is an anode electrode for capturing the emission current Ie emitted from the anode. Reference numeral 53 denotes a high-voltage power supply for applying a voltage to the anode electrode 54, and reference numeral 52 denotes an ammeter for measuring an emission current Ie emitted from the electron emission section 5 of the device. As an example, the voltage of the anode electrode is set to 1 kV to
The measurement can be performed with the range of 10 kV and the distance H between the anode electrode and the electron-emitting device in the range of 2 mm to 8 mm.

The vacuum vessel 55 is provided with equipment necessary for measurement in a vacuum atmosphere by a vacuum gauge (not shown) so that measurement and evaluation can be performed in a desired vacuum atmosphere. The exhaust pump 56 is composed of a normal high vacuum device system including a turbo pump and a rotary pump, and an ultra high vacuum device system including an ion pump and the like. The entire vacuum processing provided with the electron source substrate shown here can be heated by a heater (not shown). Therefore, by using this vacuum processing apparatus, the steps after the energization forming described above can also be performed.

FIG. 6 shows emission current Ie, element current If, and element current V measured using the vacuum processing apparatus shown in FIG.
It is the figure which showed the relationship of f typically. In FIG.
Since the emission current Ie is significantly smaller than the element current If, it is shown in arbitrary units. The vertical and horizontal axes are linear scales.

As is clear from FIG. 6, the electron-emitting device to which the present invention can be applied has three characteristic properties with respect to the emission current Ie. That is, (i) this element has a certain voltage (called a threshold, V
th) or more, the emission current Ie suddenly increases
Increases, while the emission current I is lower than the threshold voltage Vth.
e is hardly detected. That is, it is a nonlinear element having a clear threshold voltage Vth with respect to the emission current Ie. (Ii) Since the emission current Ie depends monotonically on the device voltage Vf, the emission current Ie can be controlled by the device voltage Vf. (Iii) The emission charge captured by the anode electrode 54 is:
It depends on the time for applying the element voltage Vf. That is, the amount of charge captured by the anode electrode 54 can be controlled by the time during which the device voltage Vf is applied.

As will be understood from the above description, the electron-emitting device to which the present invention can be applied can easily control the electron-emitting property according to the input signal. By utilizing this property, it is possible to apply the present invention to various fields such as an electron source and an image forming apparatus configured by arranging a plurality of electron emissions.

In FIG. 6, an example in which the element current If monotonically increases with respect to the element voltage Vf (hereinafter referred to as "MI characteristic") is shown by a solid line. The element current If is equal to the element voltage Vf
May exhibit a voltage control type negative resistance characteristic (hereinafter, referred to as “VCNR characteristic”) in some cases (not shown). These characteristics can be controlled by controlling the aforementioned steps.

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

Various arrangements of the electron-emitting devices can be employed. As an example, a large number of electron-emitting devices arranged in parallel are connected at both ends, a large number of rows of electron-emitting devices are arranged (referred to as a row direction), and in a direction orthogonal to the wiring (referred to as a column direction), There is a ladder-type arrangement in which electrons from the electron-emitting device are controlled and driven by a control electrode (also called a grid) disposed above the electron-emitting device. Apart from this, a plurality of electron-emitting devices are arranged in a matrix in the X and Y directions, and one of the electrodes of the plurality of electron-emitting devices arranged in the same row is commonly connected to a wiring in the X direction. One example is one in which the other of the electrodes of a plurality of electron-emitting devices arranged in the same column is commonly connected to a wiring in the Y direction. This is a so-called simple matrix arrangement. First, the simple matrix arrangement will be described in detail below.

The electron-emitting device to which the present invention can be applied has characteristics (i) to (iii) as described above. That is, when the electron emission from the electron-emitting device is equal to or higher than the threshold voltage, it can be controlled by the peak value and the width of the pulse voltage applied between the opposing device electrodes. On the other hand, when the voltage is equal to or lower than the threshold voltage, it is hardly emitted. According to this characteristic, even when a large number of electron-emitting devices are arranged, if a pulse-like voltage is appropriately applied to each device, the electron-emitting device is selected according to an input signal to control the amount of electron emission. it can.

Hereinafter, based on this principle, an electron source substrate obtained by arranging a plurality of electron-emitting devices to which the present invention can be applied will be described with reference to FIG. In FIG. 7, reference numeral 71 denotes a substrate on which the above-mentioned surface treatment layer is provided in advance.
72 is an X-direction wiring, and 73 is a Y-direction wiring. 74 is an electron-emitting device, and 75 is a connection line.

The m X-direction wires 72 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. The Y-direction wiring 73 includes Dy1, Dy2,. . . , Dyn
And formed in the same manner as the X-direction wiring 72. An interlayer insulating layer (not shown) is provided between the m X-directional wirings 72 and the n Y-directional wirings 73 to electrically separate them (m and n are: Both are positive integers).

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, it is formed in a desired shape on the entire surface or a part of the substrate 71 on which the X-directional wiring 72 is formed. The material and manufacturing method are appropriately set. The X-direction wiring 72 and the Y-direction wiring 73 are respectively drawn out as external terminals.

A pair of electrodes (not shown) forming the emission terminal 74 are composed of m X-directional wirings 72 and n Y-directional wirings 73.
And a connection 76 made of a conductive metal or the like.

The material forming the wiring 72 and the wiring 73, the material forming the connection 75, and the material forming the pair of element electrodes may be partially or entirely the same or different. Good. These materials are appropriately selected, for example, from the above-described materials for the device electrodes. When the material forming the element electrode is the same as the wiring material, the wiring connected to the element electrode can also be called an element electrode.

A scanning signal applying means (not shown) for applying a scanning signal for selecting a row of the emitting elements 74 arranged in the X direction is connected to the X direction wiring 72. On the other hand, a modulation signal generating means (not shown) for modulating each column of the emission elements 74 arranged in the Y direction according to an input signal is connected to the Y direction wiring 73. 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.

An image forming apparatus constituted by using the electron sources having such a simple matrix arrangement will be described with reference to FIGS. 8, 9 and 10. FIG. FIG. 8 is a schematic view showing an example of the image forming apparatus of the image forming apparatus, and FIG. 9 is a schematic view of a fluorescent film used in the image forming apparatus of FIG. FIG.
FIG. 2 is a block diagram showing an example of a drive circuit for performing display according to an NTSC television signal.

In FIG. 8, reference numeral 71 denotes an electron source substrate on which a plurality of electron-emitting devices are arranged; 81, a rear plate on which the electron source substrate 71 is fixed; 86, a fluorescent film 84 on the inner surface of a glass substrate 83;
And a face plate on which a metal back 86 and the like are formed. Reference numeral 82 denotes a support frame to which a rear plate 81 and a face plate 86 are joined by using low melting point frit glass or the like.

Reference numeral 74 corresponds to the electron-emitting portion in FIG. Reference numerals 72 and 73 denote an X-direction wiring and a Y-direction wiring connected to a pair of device electrodes of the electron-emitting device.

The envelope 88 includes the face plate 86, the support frame 82, and the rear plate 81, as described above. Since the rear plate 81 is provided mainly for the purpose of reinforcing the strength of the substrate 71, if the substrate 71 itself has sufficient strength, the separate rear plate 81 can be unnecessary. That is, the support frame 82 is directly sealed to the substrate 71,
The envelope 88 may be constituted by the face plate 86, the support frame 82, and the substrate 71. On the other hand, face plate 8
6. By installing a support (not shown) called a spacer between the rear plates 81, the envelope 88 having sufficient strength against atmospheric pressure can be formed.

FIG. 9 is a schematic diagram showing a fluorescent film. The fluorescent film 84 can be composed of only a phosphor in the case of monochrome. In the case of a color fluorescent film, it can be composed of a black conductive material 91 called a black stripe or a black matrix and a fluorescent material 92 depending on the arrangement of the fluorescent materials. The purpose of providing the black stripes and the black matrix is to make the color mixing 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,
In suppressing a decrease in contrast due to reflection of external light. 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 83 can employ a precipitation method, a printing method, or the like irrespective of monochrome or color. Usually, a metal back 85 is provided on the inner surface side of the fluorescent film 84. The purpose of providing a metal back is
The light emitted from the phosphor toward the inner surface is converted into a face plate 8.
Improve brightness by specular reflection to the 6 side, act as an electrode for applying electron beam acceleration voltage, protect phosphor from damage due to collision of negative ions generated in the envelope, etc. It is. The metal back can be manufactured by performing a smoothing process (usually called “filming”) on the surface side without the fluorescent film after manufacturing the fluorescent film, and then depositing Al using vacuum evaporation or the like.

The face plate 86 further has the fluorescent film 8
A transparent electrode (not shown) may be provided on the outer surface side of the fluorescent film 84 in order to increase the conductivity of the phosphor film 84.

When performing the above-mentioned sealing, in the case of color, it is necessary to react the phosphors of each color with electron-emitting electrons.
Sufficient alignment is essential.

An example of a method for manufacturing the image forming apparatus shown in FIG. 8 will be described below.

FIG. 13 is a schematic diagram showing an outline of an apparatus used in this step. The image forming apparatus 131 includes an exhaust pipe 132
Is connected to a vacuum chamber 133 via a gate valve 134, and further connected to an exhaust device 135 via a gate valve 134. The vacuum chamber 133 is provided with a pressure gauge 136, a quadrupole mass analyzer 137, and the like for measuring the internal pressure and the partial pressure of each component in the atmosphere. Since it is difficult to directly measure the pressure inside the envelope 88 of the image display device 131, the processing conditions are controlled by measuring the pressure inside the vacuum chamber 133 and the like.

The vacuum chamber 133 is connected to a gas introduction line 138 for introducing a necessary gas into the vacuum chamber to control the atmosphere. An introduction substance source 140 is connected to the other end of the gas introduction line 138, and the introduction substance is stored in an ampoule or a cylinder. In the middle of the gas introduction line, there is provided an introduction control means 139 for controlling the rate at which the introduced substance is introduced. As the introduction amount control means, specifically, a valve such as a slow leak valve capable of controlling the flow rate to be released, a mass flow controller, or the like can be used according to the type of the substance to be introduced.

The inside of the envelope 88 is evacuated by the apparatus shown in FIG. 13 to perform forming. At this time, for example, as shown in FIG. 14, the Y-direction wiring 73 is connected to the common electrode 141,
The element connected to one of the X-direction wirings 72 is connected to the power supply 14.
2, the forming can be performed by applying the voltage pulse at the same time. Conditions such as the shape of the pulse and the determination of the end of the processing may be selected according to the above-described method for forming the individual elements. In addition, by sequentially applying (scrolling) a pulse with a phase shifted to a plurality of X-direction wirings, it is possible to form elements connected to the plurality of X-direction wirings collectively. 1 in the figure
Reference numeral 43 denotes a current measuring resistor, and 144 denotes a current measuring oscilloscope.

After the forming is completed, an activation step is performed.
After exhausting the inside of the envelope 88 sufficiently, the organic substance is introduced from the gas introduction line 188. Alternatively, as described in the method of activating the individual element, first, the gas is evacuated by an oil diffusion pump or a rotary pump, and the organic substance remaining in the vacuum atmosphere may be used. In addition, substances other than organic substances may be introduced as necessary. By applying a voltage to each electron-emitting device in an atmosphere containing an organic substance formed in this manner, carbon or a carbon compound, or a mixture of both, is deposited on the electron-emitting portion, and the amount of emitted electrons is drastic. Is similar to the case of the individual element. At this time, the voltage may be applied by applying the same voltage pulse to the elements connected to one direction wiring by the same connection as in the above-described forming.

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

Next, an example of the configuration of a drive circuit for performing a television display based on an NTSC television number in an image forming apparatus configured using an electron source having a simple matrix arrangement will be described with reference to FIG. I do. 10, reference numeral 101 denotes an image forming apparatus; 102, a scanning circuit;
Is a control circuit, and 104 is a shift register. 105 is a line memory, 106 is a synchronization signal separation circuit, 107 is a modulation signal generator, and Vx and Va are DC voltage sources.

The image forming apparatus 101 includes terminals Dox1 to Doxm, terminals Doy1 to Doyn, and a high voltage terminal H.
It is connected to an external electric circuit via v. Terminal Dox
Scan signals for sequentially driving electron sources provided in the image forming apparatus, that is, electron emission element groups arranged in a matrix of M rows and N columns, one by one (N elements) are provided in 1 to Doxm. Is applied.

To the terminals Dy1 to Dyn, a modulation signal for controlling the output electron beam of each of the electron-emitting devices in one row selected by the scanning signal is applied. The high-voltage terminal Hv is supplied with a DC voltage of, for example, 10 kV from a DC voltage source Va. The DC voltage is applied to apply sufficient energy to the electron beam emitted from the electron-emitting device to excite the phosphor. Acceleration voltage.

Next, the scanning circuit 102 will be described. This circuit includes M switching elements inside (in the drawing, S1 to Sm are schematically shown). Each switching element selects either the output voltage of the DC voltage source Vx or 0 V (ground level), and is electrically connected to the terminals Dx1 to Dxm of the image forming apparatus 101. Each of the switching elements S1 to Sm operates based on the control signal Tscan output from the control circuit 103, and can be configured by combining switching elements such as FETs, for example.

In the case of the present embodiment, the DC voltage source Vx is such that the drive voltage applied to an element that is not scanned based on the characteristics (electron emission threshold voltage) of the electron emission element is equal to or lower than the electron emission threshold voltage. It is set to output a constant voltage such that

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

The synchronizing signal separating circuit 106 is a circuit for separating a synchronizing signal component and a luminance signal component from an NTSC television signal input from the outside, and uses a general frequency separating (filter) circuit or the like. Can be configured. The synchronizing signal separated by the synchronizing signal separating circuit 106 includes a vertical synchronizing signal and a horizontal synchronizing signal, but is shown here as a Tsync signal for convenience of explanation. The luminance signal component of the image separated from the television signal is referred to as a DATA signal for convenience. The DATA signal is input to the shift register 104.

The shift register 104 serially / parallel converts the DATA signal input serially in time series for each line of an image, and operates based on a control signal Tsft sent from the control circuit 103. (Ie, the control signal Tsft is transmitted to the shift register 104
It can be said that it is a shift clock. ). The data of one line of the serial / parallel-converted image (corresponding to the drive data of N electron-emitting devices) is converted into N parallel signals Id1 to Idn as the shift register 1
04.

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

The modulation signal generator 107 outputs the image data I '
The signal source is a signal source for appropriately driving and modulating each of the electron-emitting devices in accordance with each of d1 to I'dn, and its output signal is supplied to the image forming apparatus 1 through terminals Doy1 to Doyn.
01 is applied to the electron-emitting device.

As described above, the electron-emitting device to which the present invention can be applied has the following basic characteristics with respect to the emission current Ie. That is, a clear threshold voltage Vth is required for electron emission.
And electron emission occurs only when a voltage higher than Vth is applied. For a voltage equal to or higher than the electron emission threshold, the emission current also changes according to the change in the voltage applied to the device. From this, when applying a pulsed voltage to this element,
For example, when a voltage lower than the electron emission threshold is applied, electron emission does not occur, but when a voltage higher than the electron emission threshold is applied, an electron beam is output. At this time, the pulse peak value V
By changing m, the intensity of the output electron beam can be controlled. Further, by changing the pulse width Pw, it is possible to control the total amount of charges of the output electron beam.

Therefore, as a method of modulating the electron-emitting device according to the input signal, a voltage modulation method, a pulse width modulation method, or the like can be adopted. When implementing the voltage modulation method, a circuit of a voltage modulation method that generates a voltage pulse of a fixed length and modulates the peak value of the pulse appropriately according to input data is used as the modulation signal generator 107. be able to.

When implementing the pulse width modulation method,
As the modulation signal generator 107, a pulse width modulation type circuit that generates a voltage pulse having a constant peak value and appropriately modulates the width of the voltage pulse according to input data can be used.

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

When the digital signal type is used, it is necessary to convert the output signal DATA of the synchronizing signal separating circuit 106 into a digital signal. For this purpose, an A / D converter may be provided at the output section of the 106. In connection with this, the line memory 10
Depending on whether the output signal of 6 is a digital signal or an analog signal,
The circuit used for the modulation signal generator 107 is slightly different. That is, in the case of the voltage modulation method using a digital signal, for example, a D / A conversion circuit is used as the modulation signal generation signal 107, and an amplification circuit and the like are added as necessary. In the case of the pulse width modulation method, the modulation signal generation signal 107 includes, for example, a high-speed oscillator, a counter for counting the number of waves output from the oscillator, and a comparator for comparing the output value of the counter with the output value of the memory. (Comparator) is used. If necessary, an amplifier for amplifying the pulse width modulated signal output from the comparator to the drive voltage of the electron-emitting device can be added. In the case of the voltage modulation method using an analog signal, for example, an amplification circuit using an operational amplifier or the like can be used as the modulation signal generator 107, and a level shift circuit or the like can be added as necessary. In the case of the pulse width modulation method, for example, a voltage-controlled oscillation circuit (VOC) can be employed, and an amplifier for amplifying the voltage up to the drive voltage of the electron-emitting device can be added as necessary.

In the image display device to which the present invention can be applied, which has such a configuration, by applying a voltage to each of the electron-emitting devices 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 high voltage terminal Hv to the metal back 85 or a transparent electrode (not shown) to accelerate the electron beam. The accelerated electrons collide with the fluorescent film 84 and emit light to form an image.

The configuration of the image forming apparatus described here is an example of an image forming apparatus to which the present invention can be applied, and various modifications can be made based on the technical idea of the present invention. As for the input signal, the NTSC system has been described, but the input signal is not limited to this, and the PAL, SECAM system, etc.
A TV signal composed of a large number of scanning lines (for example,
A high-definition TV system such as the MUSE system can also be adopted.

Next, a ladder-type arrangement of the electron source and the image forming apparatus will be described with reference to FIGS.

FIG. 11 is a schematic diagram showing an example of a ladder-type arrangement of electron sources. In FIG. 11, reference numeral 110 denotes a substrate on which the surface treatment layer is formed, and 111 denotes an electron-emitting device.
112, Dx1 to Dx10 are common wirings for connecting the electron-emitting devices 111. The electron-emitting device 111
Plural pieces are arranged in parallel in the X direction on the substrate 110 (this is called an element row). A plurality of the element rows are arranged to constitute an electron source. By applying a drive voltage between the common wires of each element row, each element row can be driven independently. That is, a voltage equal to or higher than the electron emission threshold is applied to an element 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. As for the common wirings Dx2 to Dx9 between the element rows, for example, Dx2 and Dx3 can be the same wiring.

FIG. 12 is a schematic view showing an example of a panel structure in an image forming apparatus having a ladder-type electron source. 120 is a grid electrode, 121 is a hole for passing electrons, 122 is Dox1, Dox2,. . . Dox
m outside the container. 128, G1, G2,. . . An external terminal 124 made of Gn is an electron source substrate in which the common wiring between the element rows is the same wiring. In FIG. 12, FIG.
1 are denoted by the same reference numerals as those shown in these drawings. A major difference between the image forming apparatus shown here and the image forming apparatus having the simple matrix arrangement shown in FIG. 8 is whether or not the grid electrode 120 is provided between the electron source substrate 110 and the face plate 86.

In FIG. 12, a grid electrode 120 is provided between the substrate 110 and the face plate 86. The grid electrode 120 is for modulating the electron beam emitted from the emission element. In order to allow the electron beam to pass through a stripe-shaped electrode provided orthogonally to the ladder-type arrangement element row, each grid element has Corresponding circular openings 121 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 emission element.

The outer container terminal 122 and the grid outer terminal 123 are electrically connected to a control circuit (not shown).

In the image forming apparatus of 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 each electron beam to the phosphor and display an image one line at a time.

The image forming apparatus of the present invention can be used not only for the above-described television broadcast display apparatus, but also for a video conference system,
Also suitable for display devices such as computers. Furthermore, it can also be used as a component of an optical printer configured using a photosensitive drum or the like.

<Preliminary Study> Formation of a Na removal layer on a blue glass substrate, and N addition to the Na removal layer by heat treatment
The following preliminary study was conducted on the diffusion of a.

In a stream of a mixture of SO ₂ gas and air, a soda lime glass substrate (SiO ₂ : 74%, Na ₂ : 12%, Ca
_{O: 9%, K 2 O} : 3%, MgO: 2%) was heated, then hot water washed, and dried by heating further 120 ° C..

When the glass is kept at a temperature close to the glass transition temperature and the glass is brought into contact with the SO ₂ gas in this manner, Na in the glass reacts with SO ₂ to become Na ₂ SO ₄ and precipitates on the surface. Other components such as K and Ca are also considered to react in the same manner. However, since the diffusion rate of Na ions is high, Na is particularly removed from the glass substrate, and a layer having a reduced amount of Na near the surface of the blue glass substrate (desorption). Na treatment layer) is formed. N
Since a ₂ SO ₄ is water-soluble, it can be removed by washing with warm water. Although some K and Ca sulfates are formed, they are also removed by washing with warm water.

The thickness of the Na removal layer formed by this treatment can be adjusted by appropriately setting the treatment temperature and the treatment time, and the actual measurement of the thickness is performed by the secondary ion mass spectrometry. It was measured by the method (SIMS).

Then, these substrates were subjected to a heat treatment to examine how the concentration of Na on the surface of the Na-removed layer was related to the thickness of the initially formed Na-removed layer. The measurement was performed by SIMS.

The heat treatment is performed at 350 ° C. for 10 minutes.
This is a typical condition for the process of converting an organic Pd compound film into a PdO film. Na ₂ O of blue glass substrate
Is 12% (that is, in the case of the substrate used in the present study), the thickness of the Na-free layer determined from Expression (1) is about 10 μm as described above.

As a result of this study, it was found that the thickness of the Na removal layer was 1
When the thickness exceeds 0 μm, the increase in the Na concentration on the surface due to the heat treatment is substantially negligible. Therefore, if there is a Na removal layer having a thickness of about 2.4 times the value obtained based on the equation (1), that is, the value of (Dt) ^1/2 , diffusion of Na to the surface by the thermal process It was suggested that the adverse effects of

[0138]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.

<Example 1, Comparative Examples 1 and 2> (Step-1) Blue glass substrate (SiO ₂ : 74%, Na ₂
O: 12%, CaO: 9%, K ₂ O: 3%, MgO: 2
%) In a mixed air stream of air and SO ₂ at 550 ° C., followed by washing with hot water and drying to form a Na-free layer on the substrate surface (FIG. 3A). By controlling the treatment time, the thickness of the Na removal layer was reduced to 5 μm (Comparative Example 2),
The thickness was 10 μm (Example 1). Further, for comparison, Na removal
A soda-lime glass substrate was prepared, which was not subjected to any treatment but was washed only with a detergent and hot water (Comparative Example 1). In each of Comparative Examples and Examples, ten devices were prepared, and the reproducibility of characteristics was also examined.

(Step-2) Next, a photoresist layer is formed on the substrate-removed Na-treated layer 6 (on a substrate without the treated layer, on the substrate), and the device electrode is formed on the photoresist layer by photolithography. An opening corresponding to the shape was formed. On top of this, Ti5 nm, Pt
A 100 nm film was formed, the photoresist layer was dissolved and removed with an organic solvent, and device electrodes 2 and 3 were formed by lift-off (FIG. 3B). The gap L between the device electrodes was 50 μm, and the length W of the device electrode was 500 μm.

(Step-3) Next, a conductive film is formed.
First, in order to form a mask for patterning the conductive film, Cr is deposited to a thickness of 50 nm by a vacuum evaporation method, and an opening corresponding to the shape of the conductive film 4 is formed by a photolithography technique. A solution of the monoethanolamine complex was applied using a spinner, dried, and then heated at 350 ° C. for 10 minutes in air to obtain Pd.
A conductive film composed of fine particles containing O as a main component was formed, and then Cr was removed by wet etching, and a conductive film 4 having a desired shape was obtained by lift-off (FIG. 3C). The thickness of the conductive film is about 10 nm, and the width W ′ of the conductive film is 300.
μm. The sheet resistance of the conductive film was 6 × in Example 1.
10 ⁴ Ω / □, Comparative Examples 1 and 2 are about 2 to 5 × 10 ⁴ Ω / □, and when the thickness of the Na removal layer is less than 10 μm, the resistance of the conductive film 4 (PdO fine particle film) decreases. In addition, it was found that the variation of the value became large.

Thereafter, the element is schematically shown in FIG.
It was installed in a vacuum processing device. 55 is a vacuum chamber, 56
Is an exhaust device for exhausting the inside of the vacuum chamber, 50
Is a power supply for applying a voltage between the device electrodes 2 and 3 to flow a current, 50 is an ammeter for detecting a current (device current: If) flowing through the device, and 54 is an electron emitted from the electron-emitting device. , A high-voltage power supply 53 for applying a light voltage to the anode electrode, and a current 52 (emission current: Ie) flowing when electrons emitted from the electron-emitting device are captured by the anode electrode. It is an ammeter for detecting.

(Step-4) <Forming Step> The inside of the vacuum chamber was evacuated, and the pressure was increased to 1.3 × 10 ⁻⁴ Pa.
Hereinafter, a pulse voltage is repeatedly applied between the element electrodes by the power supply 51. The waveform of the voltage is as shown in FIG. 4B.
c. , Pulse interval T2 = 10 msec. And In addition,
A pulse width of 1 msec. A resistance value between element electrodes was detected by inserting a rectangular wave pulse having a peak value of 0.1 V and measuring a current flowing thereby. When the detected resistance value exceeded 1 MΩ, the application of the pulse voltage was terminated. By this processing, the electron emission unit 5
Was formed (FIG. 3D).

(Step-5) A mixed gas of N ₂ : 98% -H ₂ : 2% is introduced into a vacuum chamber, and the inside pressure is adjusted to 1 atm and maintained for 10 minutes. In order to monitor the reduction, the monitoring element which has been subjected to the same processing as in the elements of Example 1 and Comparative Examples 1 and 2 up to the step-3 is simultaneously installed in a vacuum chamber, whereby the change in the resistance value is reduced. Monitored. Example 1
In the monitoring device of Comparative Example 1, the resistance between the device electrodes started to decrease about 5 minutes after the introduction of the mixed gas, the change in resistance ended in about 8 minutes, and dropped by about two digits from the initial value. The resistance of each of the two monitoring elements decreases slowly,
In 10 minutes, the change in the resistance value was not completed, and particularly in Comparative Example 1, the change in the resistance value did not reach even one digit.

(Step-6) <Activation Step> The inside of the vacuum vessel 55 is evacuated again, and the pressure is once set to 1.3 × 10
^-4 Pa or less, and then acetone vapor was introduced into the vacuum vessel 55, the pressure was set to 2.7 × 10 ^-1 Pa, and the power supply 51
As a result, a pulse having a peak value of 20 V was applied between the device electrodes 2 and 3. As a result of this processing, the element current If detected by the ammeter 50 gradually increased and almost saturated in about 30 minutes.

(Step-7) <Stabilization Step> The entire vacuum vessel 55 is heated to about 150 ° C. by a heater (not shown).
And after 10 hours the pressure is 1.3 × 10 ^-5
Pa.

The power of the heater for heating the vacuum vessel was turned off, and the temperature was returned to room temperature. Then, the electron emission characteristics of the electron-emitting device thus produced were measured. A peak value of 20 is provided between the device electrodes 2 and 3.
V, pulse width 1 msec. , Pulse interval 10 msec.
Is applied, and the potential of the anode electrode 54 is 1 k
V, the distance between the electron-emitting device and the anode electrode was H = 4 mm. For each of the ten elements of Example 1, Comparative Examples 1 and 2,
The measured values of the device electrode If and the emission current Ie were as follows.

[0148]

[Table 1] Further, for the devices of the above Examples and Comparative Examples, the Na content in the conductive film and on the surface of the substrate was measured by SIMS. The ratio of Na to all metal elements in the conductive film is
In the first embodiment, about 800 p. p. m. Comparative Example 2 was about 25
00p. p. m. Comparative Example 1 was about 10,000 p. p.
m. The ratio of Na to all metal elements on the substrate surface was about 1.5 at% in Example 1, about 23 at% in Comparative Example 2, and about 30 at% in Comparative Example 1.

Further, when the profile of the Na concentration in the depth direction was measured by using SIMS, a result was obtained in which the concentration decreased from the inside toward the surface as shown by a curve a in FIG. In Comparative Example 1, a slight increase in the concentration was observed on the surface, and in Comparative Example 2, a remarkable increase in the concentration was observed as shown by a curve b in FIG. Also,
In Example 1, the depth at which the Na concentration represented by d ′ in the drawing became a constant value inside the substrate was about 10 μm, which coincided with the thickness of the Na removal treatment layer formed first.

Example 2 An electron source having a plurality of electron-emitting devices having the same configuration as shown in FIGS. 1A and 1B is arranged on a substrate as schematically shown in FIG. It was created according to the following procedure. The manufacturing procedure will be described with reference to FIGS.

(Step-1) A soda lime glass substrate having the same composition as in Example 1 was kept at 550 ° C. for 8 hours in a mixed gas stream of SO ₂ gas and air, and then washed with hot water and dried. By this treatment, a Na removal layer of about 50 μm was formed.

(Step-2) A 5 nm-thick C layer is formed on the base-removed Na-treated layer (surface treated layer) 6 of the substrate 71 by a vacuum evaporation method.
r, Au having a thickness of 600 nm is sequentially deposited, and a photoresist (AZ1370; manufactured by Hoechst) is formed thereon.
After exposure and development using a photomask, the Au / Cr film was patterned by wet etching, and the photoresist was dissolved and removed to form a lower wiring (X-direction wiring) 72 (FIG. 15A).

(Step-3) An interlayer insulating layer 151 made of SiO _{2 having a} thickness of 1 μm is deposited by a sputtering method (FIG. 15B), and then a photoresist pattern serving as an etching mask is formed, using CF ₄ and H ₂ . A contact hole 152 was formed in the interlayer insulating layer 151 by a reactive ion etching (RIE) method (FIG. 15C).

(Step-4) Photoresist (DR-20)
00N; manufactured by Hitachi Chemical Co., Ltd.), and then a Pt5 film was formed by sputtering.
0 nm was deposited, the photoresist was dissolved and removed, and device electrodes 2 and 3 were formed by lift-off (FIG. 15D). Element electrode spacing L = 2 μm, element electrode width (W in FIG. 1A)
Was set to 300 μm.

(Step-5) Ti having a thickness of 5 nm and a thickness of 50
Au of 0 nm was sequentially deposited by a vacuum evaporation method, and a Y-direction wiring (upper wiring) 73 was formed by the same lift-off as described above (FIG. 15E).

(Step-6) A solution of a Pd-monoethanolamine acetic acid complex was applied using a spinner, dried, and then heat-treated at 850 ° C. for 10 minutes in air to obtain Pd.
A conductive film composed of fine particles containing O as a main component was formed (FIG. 15F), and unnecessary portions were removed by dry etching to form a conductive film 4 having a desired shape (FIG. 15G). The sheet resistance of the conductive film was about 5 × 10 ⁴ Ω / □.

(Step-7) The portions other than the contact hole 152 are covered with a photoresist, and a 5 nm T
i, 500 nm of Au was sequentially deposited, the photoresist was removed, and the unnecessary portion of the deposited film was removed to bury the contact hole (FIG. 15H).

(Step-8) As shown in FIG. 8, the substrate 71 on which the electron source is formed, the rear plate 81, and the face plate 86 (the fluorescent film 84 and the metal back 85 are formed on the inner surface of the glass substrate 83). And the support frame 82 were combined and joined. A high-frequency heating getter (not shown) is disposed in the envelope, and an exhaust pipe for controlling the atmosphere in the envelope (not shown) is attached to the envelope. For joining, apply frit glass to the joint,
The heat treatment was performed at 450 ° C. for 10 minutes in the air. Under this heat treatment condition, the required thickness of the Na removal layer is about 50 μm as estimated from the expression (1), as described above. In this embodiment, a 50 μm-thick Na removal layer is formed, and the effect can be expected.

As shown in FIG. 9A, the phosphor film 84 used in this embodiment is a phosphor film 91 in which phosphors 91 are arranged in a stripe shape. First, a black stripe made of a black member 91 is formed. Phosphor 91 corresponding to three primary colors
Is formed. The material of the black member is usually composed mainly of graphite, and the phosphor is applied by a slurry method.

A metal back 85 is provided on the fluorescent film.
In the present embodiment, Al was formed by vacuum vapor deposition after smoothing the surface of the fluorescent film (usually called “filing”).

In order to improve the conductivity, the fluorescent film 8
In some cases, a transparent electrode is provided between the substrate 4 and the glass substrate 83; however, in this embodiment, no transparent electrode is provided because sufficient conductivity was obtained by the above configuration.

When performing the above-described bonding, it is necessary to exactly correspond the positions of the phosphor and the electron-emitting device of the electron source.
Carefully align.

(Step-9) In the above step, the inside of the envelope 88 constituted by the face plate 86, the rear plate 81 and the support frame 82 is evacuated through an exhaust pipe (not shown) to an exhaust device (oil diffusion pump as a main pump). ), And reduce the pressure to 1.8 × 10 ⁻⁸ Pa or less.
An electron emitting portion was formed by applying a pulse voltage between the device electrodes through the wiring of the electron source in the same manner as in Examples 1 to 3. This processing is performed for each row of elements connected to one X-direction wiring, and when the resistance value per element exceeds 1 MΩ, the processing of that row is terminated and the processing of the next row is started. This was repeated to process all the elements.

(Step-10) H in the envelope_Two: 2%-
N_Two: Introduce 98% mixed gas and leave for 10 minutes
A reduction treatment of the conductive film was performed. Then exhaust the inside of the envelope again
To 1.3 × 10 ^-3After lowering to Pa or less, wave height
Applying a pulse voltage of 20V to each element row sequentially
The activation treatment was repeatedly performed. Oil diffusion port on exhaust system
The use of a pump allows the presence of organic substances in the envelope.
The activation process is performed. Next, the exhaust system is
Switch to pump using magnetic levitation type turbo pump
By continuing to exhaust while heating the entire envelope
Stabilization process and getter treatment by high frequency heating method.
After that, the exhaust pipe was heated, fused and sealed.

(Example 3) [0165] Except that in step-1 of Example 2, a Cr vapor-deposited film was formed on the outer peripheral portion of the substrate, and a Na removal layer was not formed on this portion, the process-7 was carried out. Until then, the same steps as in Example 2 were performed.

Next, an envelope was formed in the same manner as in Step-8, but in this embodiment, the base of the electron source also functions as a rear plate. The joint between the base 71 and the support frame 82 is a portion 161 where no Na removal layer is provided.
Thereafter, Steps 9 to 10 were performed in the same manner as in Example 2. FIG.
FIG. 7 schematically shows the configuration of the image forming apparatus of this embodiment.

(Comparative Example 3) An image forming apparatus was prepared in the same manner as in Example 2, except that only the substrate was washed with a detergent and hot water instead of Step-1 of Example 2.

When the image forming apparatuses of Examples 2 and 3 and Comparative Example 3 were displayed in white on the entire surface and the luminance distribution was observed, it was found that Examples 2 and 3 showed the same level of luminance uniformity. On the other hand, in the device of Comparative Example 3, many portions were dark, and the uniformity was clearly inferior. This is mainly due to the diffusion of Na ions into the conductive film due to the heat treatment at the time of joining the members of the envelope and the like in Comparative Example 3, so that the reaction speed at the time of reducing the conductive film varies. This is probably because the resistance value varied and the electron emission characteristics differed from element to element. After the evaluation, the substrate of the electron source was removed, and the concentration of Na was measured for the interlayer insulating layer and the substrate by SIMS.
As a result, in Examples 2 and 3, Na
The concentration was about 15% as a percentage of the total metal elements, while in Comparative Example 3, it was significantly increased to 37%. Further, the profile of the Na concentration in the depth direction showed the same tendency as that of the curve a in FIG. 21 for the example, and the same tendency as the curve b for the comparative example 3.

Example 4 A soda lime glass substrate having the same composition as that used in Example 1 was washed with a detergent and pure water, and then an ammonium sulfate aqueous solution was spray-coated on the surface of the substrate and dried. Next, a heat treatment was performed at 550 ° C. for 1 hour.

In this treatment, it is considered that Na present as Na ₂ O precipitates as sodium sulfate on the substrate surface by the following reaction, and the concentration of Na ₂ O near the substrate surface decreases.

(NH ₄ ) ₃ SO ₄ → (NH ₄ ) HSO ₄ + NH ₃ (NH ₄ ) HSO ₄ + Na ₂ O → Na ₂ SO ₄ + NH ₃
+ H ₂ O Then, the substrate was washed with warm water of 80 ° C. for 1 hour and dried. As a result, a layer of about 10 μm of Na removal was formed. Hereinafter, in the same procedure as in step-2 and subsequent steps of Examples 1 to 3,
An electron-emitting device was created. When the electron emission characteristics were measured, the characteristics were almost the same as those in Example 3. When the measurement of the concentration of Na was performed in the same manner, the same tendency as in Example 3 was shown.

(Embodiment 5) This embodiment has a structure schematically shown in FIG. In the drawings, some of the members are omitted for easy understanding of the structure. The manufacturing method will be described with reference to FIG.

(Step-1) Blue sheet glass having the same composition as in Example 1 was washed with a detergent and pure water, and then the MOD paste (D) having the shape of the device electrode 171 was formed by screen printing.
U-2110; manufactured by Noritake Co., Ltd.). The MOD paste contains gold as a metal component.

After printing, drying was performed at 110 ° C. for 20 minutes, and then the MOD paste was baked by a heat treatment apparatus under the conditions of a peak temperature of 580 ° C. and a peak holding time of 8 minutes.
An element electrode 151 of 3 μm was formed. The element electrode spacing is 7
0 μm (FIG. 19A). When firing the MOD paste in this step, SO ₂ gas is generated. Thereby, a Na removal layer is formed on the surface of the blue glass substrate.

(Step-2) Next, a paste material containing silver as a metal component (NP-4028A; Noritake Co., Ltd.)
The pattern of the lower wiring 172 was formed by the screen printing method, and baked under the same conditions as in step 1 to form the lower wiring (FIG. 19B).

(Step-3) Next, using a paste containing PbO as a main component, a pattern of the interlayer insulating layer 173 is printed, and baked under the same conditions as in the step-1.
Was formed (FIG. 19C). The interlayer insulating layer is a device electrode 17.
1 has a notch so that it can be connected to an upper wiring formed in a later step.

(Step-4) In the same manner as in step-2, the upper wiring 174 is formed (FIG. 19D), and the substrate on which the wiring has been formed is washed with warm water. As a result, the sodium sulfate deposited on the substrate surface as a result of Step-1 is removed. Also, dust and the like attached to the surface in other steps are removed at the same time.

(Step-5) Next, Step-6 of Example 2
The conductive film 4 was formed in the same manner as described above (FIG. 19E). Thereafter, an image forming apparatus was formed in the same procedure as in the second embodiment.
When the characteristics were examined, almost the same results as in Example 2 were obtained.

(Example 6) A Cr vapor-deposited film was formed on the outer periphery of the substrate in the same manner as in Example 3, and then simultaneously with Example 4, an ammonium sulfate aqueous solution was spray-coated on the substrate surface and dried. It was kept for 5 hours, and then washed with hot water and dried.

Next, an image forming apparatus was formed in the same procedure as in Example 5, and the characteristics were examined. As a result, almost the same results as in Example 2 were obtained.

(Example 7) An electron source was produced by the same steps as in Example 5. However, when firing the MOD paste, the base pressed the metal mask against the outer peripheral portion so that the SO ₂ gas released from the MOD paste did not touch this portion. The image forming apparatus was assembled in the same manner as in Example 5. When the characteristics were examined, the results were almost the same as those in Examples 2 and 5. For the above Examples 5 to 7, after completion of the evaluation, the result was not more than 2 at% by SIMS, and the profile in the depth direction had the same tendency as the curve a in FIG.

(Example 8) A blue sheet glass substrate having the same composition as in Example 1 was washed with a detergent and pure water, dried, and then subjected to normal pressure CV.
Tetraethyl-orthosilicate (TEOS) using D equipment
Then, a Na capture layer made of glass (PSG) containing about 3 μm of phosphorus was formed using TrMP and Trmethylphosphate (TMP) as source gases. The content of phosphorus can be controlled by changing the mixing ratio of the two kinds of source gases. In this embodiment, the content is set to 3%.

Thereafter, an electron-emitting device was prepared in the same procedure as in Steps 2 to 7 of Example 1. When the characteristics were examined, approximately the same characteristics as in Example 1 were obtained.

[0184] In the above-mentioned Na trapping layer, a bond is generated between Na and P, and the diffusion rate of Na seems to be lower than that in ordinary glass. For this reason, Na of Example 1
It seems that the same effect can be obtained by the Na capture layer which is thinner than the treatment layer. When the concentration of Na was measured by SIMS, the concentration of Na on the surface was 2% or less relative to the total metal elements, and the profile in the depth direction was slightly steep at a position considered to be the boundary between the blue sheet glass and the Na trapping layer. The curve had the same tendency as curve a in FIG.

(Example 9) Na was applied to the surface of a soda lime glass substrate.
A 4 μm-thick Na trapping layer made of glass (potassium-substituted glass) in which a part of K was replaced with K was formed.
An electron-emitting device was formed in the same procedure as in Example 7. The characteristics were almost the same as in Example 1. In the potassium-substituted glass, the diffusion rate of Na decreases due to the so-called alkali mixing effect, and the diffusion coefficient decreases by about one digit. This effect is N
Since the ratio between a and K occurs in a wide range, the ratio between the two elements does not need to be very strict. Therefore, it is expected that the same effect can be obtained if there is a Na capture layer having a thickness of about 1/3 as compared with the Na removal layer of Example 1, but this result is correct. Is shown.

The formation of the Na trapping layer made of the potassium glass was carried out by immersing the same soda lime glass as used in Example 1 in a melt of potassium nitrate dissolved by heating to about 500 ° C. Na in a 3 μm layer from K
Was replaced with

When the Na concentration was measured, it was 5 at% with respect to the premetal element near the surface, and the profile in the depth direction had the same tendency as the curve a in FIG. N
a) The exchange between Na and K in the trapping layer is not completely performed, so that the concentration is slightly higher than that of the other examples of 5 at%, but originally the diffusion rate of Na in the Na trapping layer is slow. The adverse effect on the conductive film may be reduced as in the other embodiments.

Comparative Example 4 An electron-emitting device was manufactured in the same manner as in Example 8, except that the thickness of the Na capture layer made of PSG was changed to 2 μm.

Comparative Example 5 An electron-emitting device was produced in the same manner as in Example 8, except that the thickness of the Na trapping layer made of potassium-substituted glass was changed to 2 μm.

When the same measurement as in Example 1 was performed on the devices of Comparative Examples 4 and 5, the same characteristics as those of Comparative Example 2 were obtained, and the characteristics were inferior to those of Examples 8 and 9. I understood. The measurement results of the profiles of the amount of Na and the Na concentration in the depth direction on the surface of the conductive film and the substrate by SIMS were comparable to those of Comparative Example 2. This is Na
This is probably because the thickness of the trapping layer was not sufficient, and Na entered the conductive film made of PdO, thereby reducing the speed of the reduction treatment.

(Example 10) After cleaning a soda lime glass substrate having the same composition as in Example 1, the same treatment as in Example 9 was performed to form a Na capture layer made of K-substituted glass on the surface. The processing time was adjusted so that the thickness of this layer was 17 μm. Subsequently, an image forming apparatus having electron sources wired in a matrix was formed in the same manner as in Step-2 to Step-10 of Example 2. Observation of the luminance distribution in the same manner as in Example 2 gave almost the same results as in Example 2.
The thickness of the Na trapping layer in this embodiment is the same as that of the second embodiment.
Although it was about 1/3 of the treatment layer, it was in agreement with the expectation that the same effect as that of Example 2 was obtained.

(Example 11) In the same manner as in Step 1 of Comparative Example 2, after forming a Na-free layer having a thickness of about 5 µm,
In the same manner as in Example 8, a 2 μm-thick Na capture layer made of PSG (phosphorus content: 3%) was formed.

Thereafter, an electron-emitting device was formed in the same procedure as in Steps 2 to 7 of Example 1. After examining the characteristics,
Almost the same characteristics as in Example 1 were obtained. Na concentration is Na
It was almost the same as Example 1 except that a slightly steep change was shown at the position considered to be the boundary between the trapping layer and the Na removal layer.

Example 12 After washing a soda lime glass substrate having the same composition as that used in Example 1 with a detergent and pure water, an ammonium sulfate aqueous solution was spray-coated on the surface of the substrate and dried. Then, a heat treatment was performed at 550 ° C. for 1 hour, followed by washing with hot water at 80 ° C. and drying. Next, a Na capture layer made of PSG was formed in the same manner as in Example 8. In this example, the thickness of the Na capture layer was 1 μm, and the phosphorus content was 5%.

Thereafter, an electron-emitting device was formed in the same procedure as in Steps 2 to 7 of Example 1. After examining the characteristics,
Almost the same characteristics as in Example 1 were obtained. Na concentration is Na
It was almost the same as Example 1 except that a slightly steep change was shown at the position considered to be the boundary between the trapping layer and the Na removal layer.

(Example 13) In the same manner as in Step 1 of Example 2, a layer for removing Na is formed on the surface of a soda lime glass substrate. However, the processing time is 1 hour, and the thickness is about 10μ.
m.

Next, a Na capture layer made of PSG was formed in the same manner as in Example 8. The thickness was 1.5 μm and the phosphorus content was 9%.

Thereafter, an electron source of matrix wiring and an image forming apparatus using the same were prepared in the same procedure as in steps -2 to 10 of Example 2.

(Embodiment 14) This embodiment is almost the same in construction and manufacturing method as in Embodiment 13, except that the Na trapping layer 7 is formed on the interlayer insulating layer 131 as shown in FIG. Therefore, after forming the interlayer insulating layer, the Na capture layer was formed.

(Example 15) In the same manner as in Example 5, a mask in which a Cr vapor-deposited film was formed on the periphery of a soda lime glass substrate was used.
Heat treatment at 550 ° C. for 3 hours in a mixed gas stream of SO ₂ gas and air, followed by washing with hot water and drying to a thickness of about 10
A μm-free Na-treated layer was formed. Next, a Na capture layer made of PSG having a phosphorus content of 10% and a thickness of 1.5 μm was formed in the same manner as in Example 13. Next, the Cr deposited film was removed.

Thereafter, an electron source and an image forming apparatus were prepared in the same procedure as in the fifth embodiment.

When the image forming apparatuses of Examples 13 to 15 were evaluated, images equivalent to those of Examples 2 and 5 were obtained. The Na concentration was 2 at% or less with respect to all metal elements on the surface of the substrate, and the profile in the depth direction showed a slight steep change at the position considered to be the boundary between the Na capture layer and the Na removal layer. Showed the same tendency as in Example 2.

Example 16 A 10 μm-thick Na-free layer was formed on the surface of a soda lime glass substrate by a method similar to that used in Example 1, and then a UV-ozone ashing apparatus was used to form a substrate in an oxygen atmosphere. For 3 hours to perform ozone ashing. At this time, it is considered that the line was irradiated and the substrate surface concentration was increased to some extent. Thereafter, washing with hot water and drying were performed, and an electron-emitting device was formed in the same steps as in Example 1.
At this time, in step 5, as in the case of the first embodiment, the change in the resistance of the monitor element was observed. The value was about 80% as compared with Example 1. After forming the device, when the electron emission characteristics were measured under the same conditions as in Example 1, the device current Ie was 2.0 to 2.3.
mA and emission current were 4.0 to 4.5 μA, and the emission current was slightly increased as compared with Example 1. This is probably because the lowering of the resistance value of the conductive film reduced the voltage drop at the resistive film portion and slightly increased the voltage actually applied to the electron-emitting portion.

After the above ozone ashing treatment,
When the content of S was measured by SIMS, it was 0.1 at% or less near the substrate surface, and about 0.0 at% of the surface.
It was found that the content of S was slightly increased in a portion deeper than the 1 μm desulfurized layer. SIMS was also performed on the conductive film, and it was found to be 0.1 at% or less.

In the measurement performed after the end of the evaluation, there was no significant change in this state. The concentration of Na was also evaluated, which was almost the same as in Example 1.

Although the reason why the above-mentioned decrease occurs has not been sufficiently investigated and is not well understood, since S diffuses into the conductive film to form PdS, which is not reduced by the ordinary reduction treatment, the metal is not reduced. It remains without becoming Pd,
It is speculated that this may segregate on the surface of the fine particles forming the conductive film and hinder the progress of the reduction reaction inside the fine particles, thereby slightly increasing the resistance value. It is considered that the diffusion of S in the glass is much slower than that of Na.
By forming a desulfurization treatment layer having a thickness of about m, it is considered that the above effects can be obtained.

(Embodiment 17) After performing the same processes as in Steps 1 to 4 of Embodiment 5, the ultraviolet irradiation treatment was performed for 3 hours in an oxygen atmosphere using the same ultraviolet ozone ashing apparatus as in Embodiment 16. By performing the above, a desulfurization treatment layer was formed. Next, an image forming apparatus was formed in the same procedure as in Example 5, and the same evaluation was performed. The uniformity of the luminance was almost the same as that of Example 5, and the overall luminance was slightly higher than that of Example 5 in response to the slight increase in the emission current as in Example 16. It is estimated that this is because, similarly to the case of Example 16, the resistance value of the conductive film is lower than the case where the desulfurization treatment layer is not provided. When the same evaluation as in Example 16 was performed for the concentrations of S and Na, almost the same results were obtained.

[0208]

As described above, the removal of Na on the surface of the substrate
By forming the treatment layer, the Na trapping layer, and the desulfurization treatment layer, it is possible to suppress the variation in the characteristics of the electron-emitting device due to Na or S and the deterioration of the characteristics, and the processability such as bonding is excellent, and the cost is reduced. Using an advantageous blue plate glass as a base, it has become possible to produce an electron-emitting device, an electron source and an image forming apparatus using the same.

[Brief description of the drawings]

FIG. 1A is a schematic diagram (plan view) showing a configuration of an electron-emitting device according to the present invention. FIG. 1B is a schematic diagram (cross-sectional view) showing a configuration of an electron-emitting device according to the present invention.

FIG. 2 is a schematic diagram (cross-sectional view) showing another configuration of the electron-emitting device according to the present invention.

FIGS. 3A to 3D are schematic diagrams for explaining a manufacturing procedure of the electron-emitting device according to the present invention. FIGS.

4A and 4B are schematic diagrams of pulse voltage waveforms used for manufacturing an electron-emitting device according to the present invention.

FIG. 5 is a schematic diagram showing a configuration of a vacuum processing apparatus (measurement evaluation apparatus).

FIG. 6 shows a device voltage Vf of the electron-emitting device according to the present invention.
And a schematic diagram showing the relationship between the element current If and the emission current Ie.

FIG. 7 is a schematic diagram showing the configuration of an electron source according to the present invention.

FIG. 8 is a schematic diagram illustrating a configuration of an image forming apparatus according to the present invention.

FIG. 9 is a schematic diagram illustrating a configuration of a fluorescent film used in the image forming apparatus of the present invention.

FIG. 10 is a block diagram illustrating an example of a driving circuit.

FIG. 11 is a schematic view showing another configuration of the electron source of the present invention.

FIG. 12 is a schematic diagram illustrating another configuration of the image forming apparatus of the present invention.

FIG. 13 is a schematic diagram illustrating an outline of an apparatus used for manufacturing an image forming apparatus.

FIG. 14 is a schematic diagram showing connection of wiring in a forming step.

FIGS. 15A to 15D are schematic diagrams for explaining a manufacturing procedure of the electron source of the present invention.

FIGS. 16A to 16H are schematic diagrams for explaining a manufacturing procedure of the electron source of the present invention.

FIG. 17 is a schematic diagram showing still another configuration of the image forming apparatus of the present invention.

FIG. 18 is a schematic view showing still another configuration of the electron source of the present invention.

FIG. 19 is a schematic diagram for explaining a manufacturing procedure of the electron source having the configuration of FIG. 18;

20A is a schematic diagram (plan view) showing a configuration of a conventional surface conduction electron-emitting device, and FIG. 20B is a schematic diagram (cross-sectional view) showing a configuration of a conventional surface conduction electron-emitting device.

FIG. 21 shows a change in electric resistance of a conductive film when exposed to a mixed gas and reduced.

FIG. 22 is a schematic diagram showing a difference in a reduction reaction rate of a conductive film due to a difference in Na content.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Base (body of) 2, 3 Element electrode 4 Conductive film 5 Electron emission part 6 Surface treatment layer (Na removal layer, Na capture layer or the laminated structure of both, or desulfurization treatment layer) 21 Step forming member 50 Element Ammeter for measuring current If 51 Power supply for applying voltage to the element 52 Ammeter for measuring emission current Ie 53 High-voltage power supply 54 Anode electrode 55 Vacuum container 56 Exhaust device 71 Substrate 72 X-directional wiring 73 Y Direction wiring 74 Electron emission device 75 Connection 81 Rear plate 82 Support frame 83 Glass substrate (of face plate) 84 Fluorescent film 85 Metal back 86 Face plate 88 Envelope 91 Black conductive material 92 Phosphor 101 Image forming device 102 Scanning circuit 103 Control circuit 104 Shift register 105 Line memory 106 Synchronous signal separation circuit 107 Modulation signal generation circuit 110 Substrate 111 Electron emitting element 112 Common wiring 120 Grid electrode 121 Hole for electron passage 122 Outer container terminal connected to common wiring 123 Outer container terminal connected to grid electrode 131 Image forming device 132 Exhaust pipe 133 Vacuum chamber 134 Gate valve 135 Exhaust device 136 Pressure type 137 Quadrupole mass spectrometer 138 Gas introduction line 139 Introduction control means 140 Introduced material source 141 Common electrode 142 Power supply 143 Current measurement resistance 144 Oscilloscope 151 Interlayer insulating layer 152 Contact hole 161 Part where surface treatment layer is not provided 171 Device electrode 172 Lower wiring 173 Interlayer insulating layer 174 Upper wiring

Claims (34)

[Claims] 1. A substrate on which an electron-emitting device is disposed on a surface thereof, wherein the substrate is a substrate containing sodium, and at least a surface layer region of the substrate on which the electron-emitting device is disposed. Wherein the concentration of said sodium is smaller than that of other regions. 2. The substrate according to claim 1, wherein the surface region has a thickness in a range of 1 μm to 40 μm from a surface on which the electron-emitting devices are arranged. 3. The substrate according to claim 1, wherein a sodium concentration on a surface on which the electron-emitting device is arranged is 2% or less. 4. The substrate according to claim 1, wherein the surface region contains potassium. 5. The substrate according to claim 4, wherein the potassium substitutes for sodium in the substrate. 6. On a surface on which the electron-emitting device is arranged,
The substrate according to claim 1, further comprising a phosphorus-containing layer. 7. The concentration of phosphorus in the phosphorus-containing layer is as follows:
7. The substrate according to claim 6, which is in the range of 3% to 10%. 8. A sulfur-containing substrate, wherein the concentration of sulfur in at least a surface region of the substrate on which the electron-emitting devices are arranged is smaller than in other regions. Item 8. The substrate according to any one of items 1 to 7. 9. The substrate according to claim 8, wherein the concentration of sulfur on the surface on which the electron-emitting devices are arranged is 0.1% or less. 10. The substrate according to claim 1, wherein the electron-emitting device is an electron-emitting device including a conductive film having an electron-emitting portion between electrodes. 11. An electron source having a substrate and an electron-emitting device disposed on a surface of the substrate, wherein the substrate is a substrate containing sodium, and at least the electron-emitting device of the substrate is disposed. An electron source, wherein the concentration of sodium in a surface region on the side to be removed is lower than that in other regions. 12. The electron source according to claim 11, wherein the surface region has a thickness in a range of 1 μm to 40 μm from a surface on which the electron-emitting devices are arranged. 13. The electron source according to claim 11, wherein a sodium concentration on a surface on which the electron-emitting device is arranged is 2% or less. 14. The electron source according to claim 11, wherein said surface layer region contains potassium. 15. The electron source according to claim 14, wherein said potassium substitutes for sodium in said substrate. 16. The electron source according to claim 11, further comprising a phosphorus-containing layer on a surface on which the electron-emitting device is arranged. 17. The electron source according to claim 16, wherein the concentration of phosphorus in the phosphorus-containing layer is in a range of 3% to 10%. 18. A substrate containing sulfur, further comprising:
The electron source according to any one of claims 11 to 17, wherein the sulfur concentration in at least a surface region of the substrate on a side where the electron-emitting device is disposed is smaller than that in another region. 19. The electron source according to claim 18, wherein a sulfur concentration on a surface on which the electron-emitting device is arranged is 0.1% or less. 20. The electron source according to claim 11, wherein said electron-emitting device is an electron-emitting device including a conductive film having an electron-emitting portion between electrodes. 21. An image forming apparatus, comprising: an electron source having a substrate and an electron-emitting device disposed on a surface of the substrate; and an image forming member that forms an image by irradiating electrons from the electron source. An image forming apparatus, wherein the electron source is the electron source according to any one of claims 11 to 20. 22. A method for manufacturing an electron source comprising a substrate and an electron-emitting device disposed on the surface of the substrate, comprising: a sodium-containing surface layer at least on the side where the electron-emitting device is disposed. A method for manufacturing an electron source, comprising: forming the electron-emitting device on the surface of a substrate having a lower sodium concentration than other regions. 23. The method according to claim 23, further comprising the step of reducing the concentration of the sodium in the surface layer region to be lower than that in the other region, and including the step of precipitating sodium in the substrate as sulfate and washing the substrate. Item 23. The method for producing an electron source according to item 22. 24. The method according to claim 22, wherein the surface layer has a thickness in a range of 1 μm to 40 μm from a surface on which the electron-emitting devices are arranged. 25. The sodium concentration of the surface on which the electron-emitting device is arranged is 2% or less.
The method for producing an electron source according to any one of claims 1 to 4. 26. The method according to claim 22, wherein the surface region contains potassium. 27. The method for manufacturing an electron source according to claim 26, wherein said potassium is obtained by substituting sodium of said substrate. 28. The method of manufacturing an electron source according to claim 22, further comprising a phosphorus-containing layer on a surface on which the electron-emitting devices are arranged. 29. The method according to claim 28, wherein the concentration of phosphorus in the phosphorus-containing layer is in a range of 3% to 10%. 30. A substrate further containing sulfur, wherein the concentration of sulfur in at least the surface layer region of the substrate on the side where the electron-emitting devices are arranged is smaller than in other regions. 30. The method for manufacturing an electron source according to any one of 22 to 29. 31. The method for manufacturing an electron source according to claim 30, wherein a sulfur concentration on a surface on which the electron-emitting device is arranged is 0.1% or less. 32. The method of manufacturing an electron source according to claim 22, wherein the electron-emitting device is an electron-emitting device including a conductive film having an electron-emitting portion between electrodes. 33. A method of manufacturing an image forming apparatus, comprising: an electron source having a substrate and an electron-emitting device disposed on the surface of the substrate; and an image forming member that forms an image by irradiating electrons from the electron source. Wherein the electron source is
32. An image forming apparatus manufactured by the method according to any one of 32. 34. The method for manufacturing an image forming apparatus according to claim 33, further comprising a heating step of sealing a container containing the electron source and the image forming member.