JP2000243231A - Electron source substrate and image forming device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate of high performance by arranging a plurality of electron emission elements respectively composed of a pair of elemental electrodes formed on a glass base and a conductive thin film having a clearance portion, and specifying a content of sodium in the glass base below a predetermined value. SOLUTION: A surface conductive electron emission element is formed by a base 1, the element electrodes 2, 3, a conductive thin film and an electron emission portion 5. As the base 1, the glass of low content of impurity such as sodium and the like, the blue plate glass, the ceramics of alumina and the like, and the like can be used, preferably a glass base of below 2% of sodium content is preferably used. A laminate, manufactured by laminating SiO2 onto the base through sputtering method and the like may be used. As the glass base, a non-alkali glass substantially not including alkali metallic element, the glass of low content of alkali metallic element, and the glass containing many alkali elements, but having low content of sodium, and including potasium, rubidium, cesium and the like can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electron source substrate using an electron-emitting device, and an image forming apparatus using the electron source substrate.

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus using an electron-emitting device, an electron source substrate on which a large number of cold cathode electron-emitting devices are formed and an anode substrate provided with a transparent electrode and a phosphor are opposed in parallel to each other. 2. Description of the Related Art A flat-type electron beam display panel that has been exhausted is known. In such an image forming apparatus, the one using a field emission type electron emitting element is, for example,
[I. Brodie, "Advanced Techn
ology: flat cold-cathode C
RTs ", Information Display,
1/89, 17 (1989)]. Further, a device using a surface conduction electron-emitting device is described in, for example, U.S. Pat. S. P. No. 5,066,883 and the like. A flat-type electron beam display panel is a cathode ray tube (C) widely used at present.
(RT) It is possible to achieve a reduction in weight and screen size as compared with a display device, and it is also possible to achieve a flat display panel using liquid crystal, a plasma display, an electroluminescent display, and other flat display panels. Thus, a higher-luminance, higher-quality image can be provided. In particular, the surface conduction electron-emitting device has a simple structure and is easy to manufacture,
There is an advantage that an electron source substrate in which a large number of devices are arranged and formed over a large area can be manufactured without going through a complicated manufacturing process utilizing photolithography technology like a field emission type electron emitting device. FIG. 14 and FIG.
This shows an example of an electron source substrate using a surface conduction electron-emitting device disclosed in Japanese Patent No. 42636. FIG. 14 shows a plan view of a part of the electron source. Here, 7 is an upper wiring, 6 a lower wiring, 81 surface conduction electron-emitting devices, and 8 is an interlayer insulating layer. FIG. 15 is a perspective view of the surface conduction electron-emitting device 81 of FIG. In FIG. 15, 91 is a substrate, 2 and 3 are device electrodes, 4 is a conductive thin film having an electron emitting portion, 5 is an electron emitting portion,
The device electrodes 2 and 3 are respectively connected to a lower wiring 6 and an upper wiring 7, and the lower wiring 6 and the upper wiring 7 are electrically insulated by an interlayer insulating layer 8. Here, predetermined voltages are sequentially applied to the upper wiring 7 and the lower wiring 6 arranged in a matrix as a scanning signal and an information signal, respectively, to selectively drive a predetermined electron-emitting device located at the intersection of the matrix. it can.

[0003] Such an electron source substrate arranged in a matrix can be manufactured by using a relatively simple photolithography technique. However, when a larger substrate is formed, it is preferable to use a printing technique. In particular, as for the upper wiring to which a scanning signal is applied, since the amount of current flowing through the wiring increases as the number of elements connected to one line increases, a voltage drop occurs due to wiring resistance. Preferably, the resistance is as low as possible.
Japanese Patent Application Laid-Open No. 08-180797 discloses a manufacturing method in which wirings and interlayer insulating layers are formed by a screen printing method. Regarding other members, for example, Japanese Patent Application Laid-Open No. 09-17333 discloses a manufacturing method of forming element electrodes by an offset printing method or the like, and a manufacturing method of forming an electroconductive thin film by an inkjet method. Is disclosed in JP-A-09-69334 and the like. By using these printing techniques, a large-area electron source substrate can be easily manufactured.

Next, a surface conduction electron-emitting device will be described. The surface conduction electron-emitting device utilizes a phenomenon in which an electron is emitted by passing a current through a small-area conductive thin film formed on a substrate in parallel with the film surface. As the surface conduction electron-emitting device, a device using a SnO ₂ thin film [M. I. Elinson, RadioEn
g. Electron Phys. , 10, 1290,
(1965)], an Au thin film [G. Ditmm
er, Thin Solid Films, 9, 31
7 (1972)] and In ₂ O ₃ / S as shown in FIG.
nO ₂ thin film [M. Hartwell and
C. G. FIG. Fonsted, IEEE Trans.
ED Conf. , 519 (1975)], using carbon thin film [Hisashi Araki et al .: Vacuum, Vol. 26, No. 1, 2
2 (1983)] and the like. For example, Japanese Patent Application Laid-Open No. 02-56822 discloses a surface conduction electron-emitting device using a metal fine particle film of palladium oxide or the like.

In manufacturing a surface conduction electron-emitting device, an electron-emitting portion is generally formed on a conductive thin film by an energization process called forming. Forming is a process of applying a direct current voltage or a very slowly increasing voltage, for example, about 1 V / min, to both ends of a conductive thin film and energizing the conductive thin film to locally destroy, deform or alter the conductive thin film, thereby forming a gap. is there. After the forming process, a voltage is applied to the conductive thin film,
By passing a current through the element, electrons are emitted from the vicinity of the gap. At this time, a portion from which electrons are emitted is called an electron emitting portion.

Further, as disclosed in, for example, Japanese Patent Application Laid-Open No. 7-235255, a process called an activation process is performed on an element after forming, so that better electron emission can be obtained. The activation step can be performed by repeatedly applying a pulse voltage to the element in an atmosphere containing a gas of an organic substance, similarly to the forming treatment. From the organic substance present in the atmosphere, carbon or a carbon compound can be obtained. The element current If and the emission current Ie are remarkably increased.

A surface conduction electron-emitting device manufactured through such a process has sufficient electron emission characteristics as an electron source applicable to an image forming apparatus such as a flat panel display.

Therefore, as described above, by manufacturing a large-area electron source substrate composed of surface conduction electron-emitting devices by using a printing technique, a large-area image forming apparatus, for example, a large-screen flat panel display is manufactured. Can be realized.

[0009]

However, when an electron-emitting device having a sufficient amount of electron emission, a sufficient life, and stability is formed on a large-area electron source substrate, there are the following problems.

When a substrate made of, for example, quartz is used as an electron source substrate for an image forming apparatus having a large area of several tens of inches, it is used for other than the electron source substrate in order to make the thermal expansion coefficients of members used in the image forming apparatus uniform. It is necessary to use quartz also for the glass member, and as a result, the cost increases and the glass member is not suitable for mass production. In addition, it is necessary to select a special process such as no practical frit glass for sealing quartz. Therefore, on the assumption that the cost is reduced, it is preferable to use an alkali-containing glass such as soda lime glass (blue plate glass). However,
In the surface conduction electron-emitting device, since the electron-emitting portion is formed in contact with the substrate surface, a heat process at the time of forming the device or heat when driving the device is transmitted to the surface of the alkali-containing glass, and the alkali metal Among them, precipitation of sodium metal or sodium compound is particularly likely to occur. When sodium is deposited near the element, a part of the element is contained in the conductive thin film, thereby changing the electrical properties of the conductive thin film. It causes fluctuation and deterioration of characteristics.

It is also conceivable to provide a coating layer on the surface of the soda lime glass substrate to prevent the precipitation of sodium. However, if the sodium content in the substrate is high, sodium is reduced due to the difference in concentration between the coating layer and the glass substrate. There was a risk of diffusion into the coat layer.

An object of the present invention is to solve the above-mentioned problems, that is, the deposition of sodium metal or a sodium compound from a soda lime glass substrate changes the electrical properties of a conductive thin film, thereby destabilizing an element forming process such as a forming step. The purpose of the present invention is to provide a high-performance electron source substrate, which is capable of maintaining a good image for a long time. It is an object to provide an area image forming apparatus.

[0013]

That is, an electron source substrate according to the present invention comprises an electron-emitting device comprising a glass substrate and a conductive thin film having a pair of device electrodes and a gap formed on the glass substrate. A plurality of electron source substrates, wherein the glass substrate has a sodium content of 2% or less.

Further, as the conductive thin film having the gap, a thin film containing Pd or PdO or a mixture thereof as a main component is preferably used, and the sodium content of the conductive thin film is set to 0.1% or less. It is desirable.

Further, as the above-mentioned electron-emitting device, a surface conduction electron-emitting device is preferably used, and in the above-mentioned electron-emitting portion, one having carbon or a carbon compound or a deposit containing these as a main component is preferable. Can be used.

Further, the present invention provides an electron source substrate for arranging a plurality of the above-mentioned electron-emitting devices on a substrate and emitting electrons in response to an input signal, and arranging a plurality of the electron-emitting devices on the substrate in parallel. A plurality of rows of electron-emitting devices having both ends of each element connected to a metal wiring, and furthermore, an electron source substrate having a modulating means, and m X electrically insulated from each other on the substrate.
The present invention is preferably applied to an electron source substrate in which a plurality of electron-emitting devices in which a pair of device electrodes of the electron-emitting device are connected to a directional metal wiring and n Y-direction metal wires.

Further, the present invention also includes an image forming apparatus formed of an image forming member and the above-mentioned electron source substrate, which forms an image based on an input signal.

According to the present invention, by using a substrate having a low sodium content as an electron source substrate, it is possible to suppress the precipitation of sodium metal or a sodium compound and prevent sodium from being mixed into the conductive thin film of the electron-emitting device. So you can
Instability in the forming and activation process is reduced,
A stable and reproducible electron source substrate can be manufactured. Further, since further precipitation of sodium due to heat generation during driving of the electron-emitting device can be prevented, stable and good electron-emitting characteristics can be obtained for a long time.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Explanation of Electron Emitting Element) Before describing the electron source substrate of the present invention, general structures and characteristics of individual electron emitting elements that can be used for the electron source substrate of the present invention will be described. This will be described with reference to FIGS.

FIGS. 8A and 8B are a plan view and a sectional view, respectively, showing the structure of a basic surface conduction electron-emitting device. In FIG. 8, 1 is a base, 2 and 3 are device electrodes, 4 is a conductive thin film, and 5 is a gap.

The element electrode interval L, the element electrode length W, the shape of the conductive thin film 4 and the like are appropriately designed depending on the application form of the element. For example, in a display device such as a television, a pixel size corresponding to a screen size is used. In particular, a high-definition television requires a small pixel size and high definition. Therefore, in order to obtain a sufficient luminance even when the size of the electron-emitting device is limited, it is designed so that a sufficient emission current is obtained.

The element electrode interval L is from several tens nm to several hundred μm.
Yes, photolithography technology that is the basis of the method for manufacturing device electrodes, that is, the performance of the exposure machine and the etching method,
In addition, although it is set by the voltage applied between the device electrodes, it is preferably several μm to several tens μm.

The element electrode length W and the film thickness d of the element electrodes 2 and 3 are appropriately designed based on the resistance of the electrodes, the connection with the XY wiring, and the arrangement of a large number of electron sources.
Usually, the length W of the device electrodes 2 and 3 is from several μm to several hundred μm.
The thickness d of the device electrodes 2 and 3 is several nm or several μm.

Various methods are conceivable as a method of manufacturing the electron-emitting device, one example of which is shown in FIG. Hereinafter, a method of manufacturing the electron-emitting device will be sequentially described with reference to FIGS.

1) After sufficiently washing the substrate 1 with a detergent, pure water and an organic solvent, depositing the device electrode material by a vacuum deposition method, a sputtering method or the like, and forming the device electrodes 2 and 3 by photolithography (FIG. 1). 9 (a)).

2) An organic metal film is formed between the element electrode 2 and the element electrode 3 provided on the base 1 by applying and drying an organic metal solution. Thereafter, the organic metal film is heated and baked, and is patterned by lift-off, etching, or the like to form the conductive thin film 4 (FIG. 9).
(B)).

3) Subsequently, when a later-described forming process is performed by applying a pulse-like voltage or a rising voltage between the element electrodes 2 and 3 by a power supply (not shown), the structure of the conductive thin film 4 is The changed gap 5 is formed (FIG. 9C). By this energization process, electrons are emitted from the vicinity of the gap 5 formed in the conductive thin film 4. Electrical processing after the forming processing is performed in the measurement and evaluation apparatus shown in FIG. The measurement evaluation device will be described below.

The general basic characteristics of the electron-emitting device applicable to the present invention will be described with reference to FIGS.

FIG. 11 shows a typical example of the emission current Ie, the device current If, and the device voltage Vf measured by the measurement / evaluation apparatus shown in FIG. Since the emission current Ie is significantly smaller than the element current If, FIG. 11 is shown in arbitrary units, and each of them is a linear scale. FIG.
As is clear from FIG. 1, the electron-emitting device of this example has three properties with respect to the emission current Ie.

First, in the device of this embodiment, when a device voltage higher than a certain voltage (called a threshold voltage, Vth in FIG. 5) is applied, the emission current Ie sharply increases, while the threshold voltage Vth Below, the emission current Ie is hardly detected.
That is, a clear threshold voltage V for the emission current Ie
This is a non-linear element having th.

Second, since the emission current Ie depends on the device voltage Vf, the emission current Ie can be controlled by the device voltage Vf.

Thirdly, the amount of charge discharged by the anode electrode 34 depends on the time during which the device voltage Vf is applied. That is, the amount of charge captured by the anode electrode 34 can be controlled by the time during which the device voltage Vf is applied.

When the characteristics of the surface conduction electron-emitting device described above are used, the electron emission characteristics can be easily controlled in accordance with an input signal. Further, in the electron source substrate of the present invention, since the sodium content of the base 1 is set to 2% or less, each electron-emitting device has stable and high-luminance electron emission characteristics for a long time, and is applicable to various fields. Can be expected.

(Description of Electron Source Substrate) The present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram (plan view) showing an example of the electron source substrate of the present invention, and shows only a part of the electron source substrate. FIG. 2A is an enlarged bird's-eye view of one electron-emitting device of the electron source substrate shown in FIG. FIG. 2B is a cross-sectional view taken along the line AA ′ in FIG.

In FIGS. 1, 2 and 3, 1 is a substrate,
2, 3 are device electrodes, 4 is a conductive thin film, 5 is a gap, 6,
Reference numeral 7 denotes a wiring connected to the device electrodes 2 and 3, respectively, and reference numeral 8 denotes an interlayer insulating layer for electrically insulating the wirings 6 and 7.
The wirings 6 and 7 may be referred to as a Y-direction wiring and an X-direction wiring, respectively, in view of the coordinates in FIG. 1, and may be referred to as a lower wiring and an upper wiring, respectively, depending on the positional relationship with the insulating layer 8.

In the present invention, for example, glass with reduced impurities such as sodium, soda lime glass, ceramics such as alumina, etc. are used as the substrate 1, and preferably, a glass substrate having a low sodium content is used. In addition, Si substrates are formed on these substrates by sputtering or the like.
A laminate in which O ₂ is laminated may be used.

The glass substrate having a low sodium content ratio is a non-alkali glass containing substantially no alkali metal element, a glass having a low alkali metal element content, and containing a large alkali metal element but having a low sodium content ratio.
A glass containing potassium, rubidium, cesium, or the like. Although described in detail later, the sodium content of these glass substrates is 2% or less.

Here, quartz glass is known as a glass having a low sodium content. However, as described above, quartz glass becomes hot due to the high temperature of the glass frit used for sealing when an image display device is manufactured. It is not suitable for a large-area image display device due to high cost.

The materials of the opposing device electrodes 2 and 3 are as follows.
It is preferable to have a stable conductivity even after the subsequent heat treatment step. For example, a metal thin film mainly composed of a noble metal such as Au, Pt, Pd or an alloy thereof is used.

The film thickness of the device electrodes 2 and 3 is preferably about several tens of nm because it has sufficient conductivity and the step coverage of the conductive thin film 4 is good.

When the above-mentioned noble metal thin film is formed on the substrate 1, a sufficient adhesion strength may not be obtained. At this time, a base metal material such as Ti or Cr may be formed as an undercoat in order to increase the adhesion between the device electrodes 2 and 3 and the base 1.

As the conductive thin film 4, a fine particle film composed of fine particles is preferably used in order to obtain good electron emission characteristics.

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

Therefore, the material of the conductive thin film 4 should be selected from those having a moderately high melting point and capable of forming the gap 5 having good electron emission characteristics at a relatively low forming power. Good.

The thickness of the conductive thin film 4 is set in consideration of the step coverage of the device electrodes 2 and 3, the resistance between the device electrodes 2 and 3, a forming condition described later, and the like. In order to obtain electron emission characteristics, several nm
A fine particle film of about several nm to several tens nm composed of about fine particles is preferably used.

Under the above-mentioned conditions, PdO can be easily formed into a thin film by baking an organic palladium compound in the air, has relatively low electric conductivity because it is a semiconductor, has low electric power for forming, Alternatively, the conductive thin film 4 can be easily reduced to metal palladium, so that the film resistance can be reduced.
It can be used as a suitable material.

The durability of the PdO fine particle film is sufficient for use as an electron-emitting device. However, when sodium is mixed in the PdO fine particle film, the electrical characteristics become unstable.

It is not always clear why the above problem occurs when sodium is mixed in the PdO fine particle film. However, when sodium is contained in the film in an amount exceeding 0.1%, the electric resistance is lowered by about one digit at the maximum, and the forming step or the activation step described later becomes extremely unstable. Further, as described above, when the film resistance is reduced by reduction, an extremely long reduction time is required.

When the substrate 1 contains sodium, sodium precipitates on the surface of the substrate in a heating step in a step of forming an electron source substrate described later. If the sodium precipitated on the substrate surface exceeds 0.1% and mixes with the conductive thin film 4, the above-described problem occurs. In some cases, sodium is further precipitated due to heat generated when the element is driven. Also in this case, if sodium exceeds 0.1% in the conductive thin film 4, the electrical characteristics of the conductive thin film 4 fluctuate, causing instability and deterioration.

Therefore, the maximum sodium content that can be contained in the substrate 1 in the present invention is such that the concentration of sodium contained in the conductive thin film 4 is 0.1% even during the forming step, the activation step, and the driving. Limited to no more.

As a preliminary study, a substrate in which the sodium content of the SiO ₂ —Na ₂ O binary glass was changed in various ways was prepared, and after passing through a heating step described later, the amount of sodium mixed in the PdO fine particle film was determined by the secondary ion mass. Analysis (SIMS)
As a result, it was found that the maximum value of the sodium content in the substrate was 2% or less so that the amount of sodium contained in the PdO fine particle film did not exceed 0.1%.
In this specification, when the content is indicated by%, it is indicated by the content measured by the secondary ion mass spectrometry.

The gap 5 is a crack formed in a part of the conductive thin film 4, and electrons are emitted from the vicinity of the gap 5. Inside the gap, conductive fine particles having a particle size of several nm to several tens nm, that is, PdO or P
There may be a case where a large number of fine particles of d metal are present, and this depends on the manufacturing method such as the thickness of the conductive thin film 4 and the energization processing conditions described later. The conductive fine particles are similar to some or all of the elements of the material constituting the conductive thin film 4. Further, a part of the gap 5 and the conductive thin film 4 near the gap 5 have carbon and a carbon compound through an activation step described later. The role of carbon and carbon compounds is presumed to control the electron emission characteristics as a material constituting the electron emission portion.

The wirings 6 and 7 are for supplying power to a plurality of electron-emitting devices as shown in FIG.

The m X-directional wirings 7 are DX1, DX2,.
..DXm, n Y-direction wiring 6 is DY1, DY2,.
The material, the film thickness, the wiring width, and the like are designed so that a substantially uniform voltage is supplied to a large number of electron-emitting devices. These m X-directional wires 7 and n Y wires
Between the directional wirings 7, an interlayer insulating layer 8 is provided and electrically separated to form a matrix wiring (these m and n).
Are both positive integers).

The shape, material, film thickness, and manufacturing method of the interlayer insulating layer 8 can be appropriately set so as to withstand the potential difference at the intersection of the wiring 6 and the wiring 7, but can be formed by a printing method like the wirings 6 and 7. Preferably, a thick film layer of glass obtained by printing a glass paste is used.

In the configuration shown in FIG. 1, that is, in the configuration of the matrix arrangement, a scanning signal (not shown) for applying a scanning signal for selecting a row of the electron-emitting devices arranged in the X direction is applied to the X-direction wiring 7. Means are connected, and the Y-direction wiring 6
Is connected to a modulation signal generating means (not shown) for modulating each column of the electron-emitting devices arranged in the Y direction according to an input signal.

The driving voltage applied to each electron-emitting device is
It is supplied as a difference voltage between the scanning signal and the modulation signal applied to the element, and individual elements can be selected using a simple matrix wiring and can be independently driven.

On the other hand, in addition to the above, each of a large number of electron-emitting devices arranged in parallel is connected at both ends, a large number of rows of electron-emitting devices are arranged, and the electron-emitting devices are arranged in a direction orthogonal to the wiring. There is a ladder-like arrangement in which electrons from the electron-emitting devices are controlled and driven by a control electrode arranged above, but the present invention is not particularly limited by these arrangements.

Now, various methods are conceivable as a method of manufacturing the electron source substrate of the present invention. One example is shown in FIGS. Hereinafter, a method of manufacturing the electron source substrate will be sequentially described with reference to FIGS.

1) After sufficiently cleaning the glass substrate 1 having a sodium content of 2% or less with a detergent, pure water and an organic solvent, the element electrode material is deposited by a vacuum evaporation method, a sputtering method or the like, and the photolithography technique is used. The device electrode 2,
3 is formed (FIG. 3A). The element electrodes 2 and 3 can also be formed by applying a printing technique such as offset printing, applying an organometallic paste, and then firing the paste.

2) On the substrate 1 on which the device electrodes 2 and 3 are formed,
A pattern of a conductive paste is formed by a screen printing method, and the lower wiring 6 made of metal is formed by firing the pattern of the conductive paste (FIG. 3B).

3) Further, an interlayer insulating layer 8 is formed at a desired position of the lower wiring 6, that is, at a position crossing the upper wiring 7 to be formed in a subsequent step (FIG. 3C). The interlayer insulating layer 8 can also be formed by forming a glass paste pattern by a screen printing method and firing the glass paste pattern. When it is desired to increase the film thickness in order to impart sufficient insulating properties to the interlayer insulating layer 8, the printing and baking can be repeated a desired number of times.

4) Subsequently, the upper wiring 7 is formed so as to intersect on the interlayer insulating layer 8 formed on the lower wiring 6 (FIG. 4A). Similarly to the lower wiring 6, the upper wiring 7 can be formed by forming a pattern of a conductive paste and firing the pattern of the conductive paste.

5) Device electrode 2 provided on base 1
A film made of an organic palladium compound is formed by applying and drying a solution of an organic palladium compound between the substrate and the element electrode 3. Thereafter, the organic palladium compound film is heated and baked, and is patterned by lift-off, etching, or the like to form a conductive thin film 4 made of PdO fine particles (FIG. 4B). Note that, here, the description has been made with the application method of the organometallic solution, but the present invention is not limited thereto, and is formed by a vacuum evaporation method, a sputtering method, a CVD method, a dispersion coating method, a dipping method, a spinner method, an inkjet method, or the like. In some cases.

6) Subsequently, when an energizing process called forming is performed between the device electrodes 2 and 3, that is, between the wirings 6 and 7 by applying a pulse-like voltage or a rising voltage from a power supply (not shown), the conductivity becomes higher. A gap 5 having a changed structure is formed at the portion of the conductive thin film 4 (FIG. 4C). This energization treatment locally destroys, deforms, or alters the conductive thin film 4, and emits electrons from the vicinity of the portion where the crack structure is formed.

In the forming process, there are a case where a pulse having a constant pulse peak value is applied and a case where a voltage pulse is applied while increasing the pulse peak value.

First, FIG. 5A shows a voltage waveform when a pulse having a constant pulse height is applied. In FIG. 5A, T1 and T2 are the pulse width and pulse interval of the voltage waveform, T1 is 1 sec to 10 msec, T2 is 10 μsec to 100 msec, and the peak value of the triangular wave (the peak voltage at the time of forming) is appropriately selected. I do.

Next, FIG. 5B shows a voltage waveform when a voltage pulse is applied while increasing the pulse peak value. In FIG. 5B, T1 and T2 are the pulse width and pulse interval of the voltage waveform, and T1 is 1 sec to 10 ms.
ec and T2 are set to 10 μsec to 100 msec, and the peak value (peak voltage at the time of forming) of the triangular wave is increased by, for example, about 0.1 V steps.

In the forming process, a pulse voltage of, for example, about 0.1 V is inserted between the forming pulses so that the conductive thin film 4 is not locally broken or deformed, and the element current is measured. The process ends when the current decreases below a predetermined value.

7) Next, an activation process is appropriately performed on the formed element. The activation process is performed by applying a pulse voltage in the same manner as the above-described forming process in an atmosphere containing an organic substance. Is obtained by introducing In the case where a vacuum envelope is formed using an electron source substrate as in an image forming apparatus described later, the activation process can be performed by introducing an organic substance into the vacuum envelope.

FIG. 12 shows an example of the voltage waveform of the applied voltage in the activation step. In the figure, T1 and T2
Are the pulse width and pulse interval of the voltage waveform, respectively.

Suitable organic substances include alkanes, alkenes, aliphatic hydrocarbons of alkynes, aromatic hydrocarbons, alcohols, aldehydes, ketones, amines, nitriles, phenols, carboxyls, sulfonic acids and the like. can be mentioned organic acids such as, specifically, methane, ethane, saturated hydrocarbon represented by propane C _n H _{2n + 2,} ethylene, expressed by a composition formula such as propylene, etc. C _n H _2n Unsaturated hydrocarbons, benzene, toluene, methanol, ethanol, formaldehyde, acetaldehyde, acetone, methyl ethyl ketone, methylamine, ethylamine, phenol, benzonitrile, acetonitrile, formic acid, acetic acid, propionic acid and the like.

By this treatment, carbon or a carbon compound is deposited on the device from organic substances existing in the atmosphere,
The element current If and the emission current Ie change remarkably. The end of the activation step is determined based on the device currents If and / or
Alternatively, the measurement is appropriately performed while measuring the emission current Ie. The pulse width, pulse interval, pulse crest value, and the like are set as appropriate.

Carbon and carbon compounds include, for example, graphite (including so-called HOPG, PG, GC; H
OPG is a crystal structure of almost perfect graphite, PG is a crystal having a crystal grain of about 20 nm and a slightly disordered crystal structure, GC
Indicates that the crystal grain is about 2 nm and the disorder of the crystal structure is further increased. ) And amorphous carbon (refers to amorphous carbon and a mixture of amorphous carbon and the aforementioned microcrystals of graphite).

8) The electron source substrate thus manufactured is preferably subjected to a stabilization step. This step is a step of exhausting a residue of the organic substance introduced during the activation treatment. The pressure in the vacuum vessel is preferably 1 to 3 × 10 ⁻⁷ Torr or less, and more preferably 1 × 10 ⁻⁸ Torr or less.
It is preferable to use a vacuum exhaust device that does not use oil so that the oil generated from the device does not affect the characteristics of the element. Specifically, a vacuum exhaust device such as a sorption pump or an ion pump can be used. Further, when the inside of the vacuum vessel is evacuated, it is preferable that the entire vacuum vessel is heated so that the organic substance molecules adsorbed on the inner wall of the vacuum vessel and the electron source substrate are easily evacuated. The heating conditions at this time are desirably as long as possible at 80 to 250 ° C., preferably 150 ° C. or more, but are not particularly limited to these conditions. This is performed under conditions appropriately selected according to various conditions.

The atmosphere at the time of driving after performing the stabilization step is preferably the same as that at the end of the stabilization process, but is not limited to this. If the organic substance is sufficiently removed, Even if the pressure itself increases somewhat, it is possible to maintain sufficiently stable characteristics.

By adopting such a vacuum atmosphere, the deposition of new carbon or carbon compound can be suppressed.
As a result, the element current If and the emission current Ie are stabilized. (Description of Image Forming Apparatus) The above is the manufacturing process of the electron source substrate in the present invention. An example in which the image forming apparatus is configured using the electron source substrate will be described below with reference to FIGS. . FIG. 6 is a basic configuration diagram of the image forming apparatus, and FIG. 7 is a fluorescent film.

In FIG. 6, reference numeral 61 denotes an electron source substrate on which a plurality of electron-emitting devices are arranged; 62, a rear plate on which the electron source substrate 61 is fixed; 67, a fluorescent film 65 on the inner surface of a glass substrate 64;
And a face plate on which a metal back 66 and the like are formed. Reference numeral 63 denotes a support frame. The rear plate 62, the support frame 63, and the face plate 67 are coated with frit glass or the like, and are heated and fired in the air or nitrogen to seal them, thereby forming an envelope 69. I do. Here, it is preferable that the frit glass be used in accordance with the coefficient of thermal expansion of the substrate because peeling, deformation, cracking, and the like of the substrate hardly occur.

The envelope 69 includes the face plate 67, the support frame 63, and the rear plate 62 as described above. However, since the rear plate 62 is provided mainly for reinforcing the strength of the substrate 61, If the substrate itself has sufficient strength, the separate rear plate 62 is unnecessary, and the substrate 6
1, a support frame 63 is directly sealed, and a face plate 67,
The envelope 69 may be constituted by the support frame 63 and the substrate 61.

On the other hand, by providing a support (not shown) called a spacer between the face plate 67 and the rear plate 62, an envelope 69 having sufficient strength against atmospheric pressure can be formed. .

FIG. 7 shows a fluorescent film. The fluorescent film 65 is made of only a phosphor in the case of monochrome, but is a black conductive material called a black stripe or a black matrix depending on the arrangement of the phosphor in the case of a color fluorescent film.
1 and a phosphor 72. Black stripe,
The purpose of providing the black matrix is to make the color separation between the phosphors 72 of the three primary color phosphors required for color display black so that color mixing and the like become inconspicuous, and to reduce external light in the phosphor film 65. It is to suppress a decrease in contrast due to reflection. The material of the black conductive material 71 such as a black stripe is not limited to the commonly used material containing graphite as a main component, as long as it is conductive and has little light transmission and reflection. is not.

The method of applying the phosphor onto the glass substrate 64 is not limited to monochrome or color, but may be a precipitation method, a printing method, or the like.

A metal back 66 is usually provided on the inner side of the fluorescent film 65. The purpose of the metal back 66 is
Improving the brightness by mirror-reflecting the light toward the inner surface side of the light emitted from the phosphor 72 toward the face plate 67, acting as an electrode for applying an electron beam accelerating voltage, This is to protect the phosphor 72 from damage caused by the collision of the generated negative ions. After the fluorescent film 65 is formed, the metal back 66 is subjected to a smoothing process (usually called filming) on the inner surface of the fluorescent film 65.
And then depositing Al using vacuum evaporation or the like.

The face plate 67 is further provided with a fluorescent film 6.
A transparent electrode (not shown) may be provided on the outer surface side of the fluorescent film 65 in order to increase the conductivity of the phosphor 5.

When the above-mentioned sealing is performed, in the case of color, since the phosphors of each color must correspond to the electron-emitting devices, it is necessary to perform sufficient alignment. Envelope 69
Is sealed at a vacuum degree of about 1 × 10 ⁻⁷ Torr through an exhaust pipe (not shown). In addition, the envelope 6
In order to maintain the degree of vacuum after sealing of No. 9, getter processing may be performed. This is because the getter disposed at a predetermined position (not shown) in the envelope 69 is heated by a heating method such as resistance heating or high-frequency heating immediately before or after the envelope 69 is sealed. This is a process for forming a deposited film. The getter is usually composed mainly of Ba or the like, and, for example, 1 × 10 ⁻⁵ or 1 × 1
The vacuum degree of 0 ^-7 Torr is maintained.

In the image display device of the present invention completed as described above, electrons are emitted by applying a voltage to each electron-emitting device through the outer terminals Dox1 to Doxm, Doy1 to Doyn, and the metal back 66 or the metal back 66 or An image is displayed by applying a high voltage of several kV or more to a transparent electrode (not shown), accelerating the electron beam, causing the electron beam to collide with the fluorescent film 65, and exciting and emitting light.

The configuration described above is a schematic configuration necessary for producing a suitable image forming apparatus used for display and the like, and detailed portions such as materials of each member are limited to those described above. Instead, it is appropriately selected so as to be suitable for the use of the image display device.

[0088]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to specific examples, but the present invention is not limited to these examples, and each element within a range in which the object of the present invention is achieved. This also includes those in which substitutions or design changes have been made. (Embodiment 1) The basic configuration of an electron source substrate according to the present embodiment is the same as in FIGS. The method for manufacturing the electron source substrate in this embodiment is shown in FIGS.
Hereinafter, a basic configuration and a manufacturing method of the image forming apparatus according to the present invention will be described with reference to FIGS.

FIGS. 3 and 4 show the manufacturing process in the vicinity of one electron-emitting device in an enlarged manner for the sake of simplicity. In this embodiment, an example of an electron source substrate in which a large number of electron-emitting devices are arranged in a simple matrix is shown. It is.

Step-a Cleaned alkali-free glass (Corning # 173)
7) 5 nm thick Ti and 50 nm thick Pt are sequentially deposited on the substrate 1 by a sputtering method. Thereafter, the pattern of the device electrodes 2 and 3 is formed of photoresist, the Pt / Ti deposited layer other than the pattern of the device electrodes 2 and 3 is removed by dry etching, and finally the photoresist pattern is removed. 2 and 3 are formed (FIG. 3
(A)).

Step-b On the substrate 1 on which the device electrodes 2 and 3 are formed, a pattern of the wiring 6 is formed by screen printing using an Ag paste, dried, baked at 500 ° C., and formed into a desired shape of Ag. Is formed (FIG. 3B).

Step-c Next, a pattern of the interlayer insulating layer 8 is formed by screen printing using a glass paste.
Baking. In order to obtain sufficient insulating properties, printing, drying, and firing of the glass paste are repeated again to form an interlayer insulating layer 8 of glass having a desired shape (FIG. 3).
(C)).

Step-d The pattern of the upper wiring 7 is formed by screen printing using an Ag paste so as to intersect the lower wiring 6 at the portion where the interlayer insulating layer 8 is formed, dried, and baked at 500 ° C. Then, an upper wiring 7 of a desired shape made of Ag is formed (FIG. 4A).

By the above steps a to d, the device electrodes 2, 3
Are connected in a matrix by the wirings 6 and 7 to form a substrate.

Step-e Next, the conductive thin film 4 is formed so as to extend between the gaps between the device electrodes 2 and 3. The conductive thin film 4 is formed by applying an organic palladium solution to a desired position by an inkjet method, and performing a heating and baking treatment at 350 ° C. for 30 minutes (FIG. 4).
(B)). Thus, a conductive thin film 4 composed of fine particles containing PdO as a main component and having a thickness of about 10 nm is obtained.

Through the above steps a to e, the lower wiring 6, the interlayer insulating layer 8, the upper wiring 7, the device electrodes 2, 3 and the conductive thin film 4 were formed on the base 1, and an electron source substrate was manufactured.

Hereinafter, using the electron source substrate of this embodiment,
An example of the configuration of the image forming apparatus will be described with reference to FIGS. After fixing the electron source substrate 61 manufactured as described above on the rear plate 62, the
A face plate 67 (formed by forming a fluorescent film 65 and a metal back 66 on the inner surface of a glass substrate 64) is disposed above a support frame 63, and
7. A frit glass was applied to the joint between the support frame 63 and the rear plate 62 and sealed by baking at 380 ° C. for 30 minutes in the air. Also, the electron source substrate 6 on the rear plate 62
1 was also fixed with frit glass.

The phosphor film 65 is made of only a phosphor in the case of monochrome, but in this embodiment, the phosphor is formed in a stripe shape, a black stripe is formed first, and each color phosphor is applied to the gap. Then, a fluorescent film 65 was manufactured. As the material for the black stripe, a material mainly containing graphite, which is generally used, was used. A slurry method was used to apply the phosphor to the glass substrate 64.

A metal back 66 is usually provided on the inner side of the fluorescent film 65. Metal back is the fluorescent film 65
After the fabrication, the inner surface of the fluorescent film 65 was subjected to a smoothing process (usually called filming), and then the Al film was fabricated by vacuum evaporation.

The face plate 67 is further provided with a fluorescent film 6.
In some cases, a transparent electrode (not shown) is provided on the outer surface side of the fluorescent film 65 in order to increase the conductivity of the phosphor layer 5. However, in this embodiment, since the metal back 66 alone provided sufficient conductivity, Omitted. At the time of performing the above-mentioned sealing, in the case of color, since the phosphors of each color must correspond to the electron-emitting devices, sufficient alignment was performed.

The atmosphere in the glass container completed as described above is exhausted by a vacuum pump through an exhaust pipe (not shown), and after reaching a sufficient degree of vacuum, external terminals Dox1 to Doxm and Doy1 to Doyn. A voltage was applied to the device electrodes 2 and 3 through the process to form the conductive thin film 4. The voltage waveform of the forming process is the same as that shown in FIG.

In this embodiment, T1 is 1 msec, and T2 is 1
The process was performed at 0 msec in a vacuum atmosphere of about 1 × 10 ⁻⁵ Torr.

Thereafter, the whole glass container was heated at 200 ° C. for 2 hours while evacuating with a vacuum pump. At this time, the conductive thin film 4 containing PdO as a main component was thermally reduced to become a film containing Pd as a main component.

Next, the exhaust was continued until the pressure in the panel reached the level of 10 ^-8 Torr, and then the organic substance was injected into the panel from the exhaust pipe of the panel so that the total pressure became 1 × 10 ^-6 Torr. Introduced and maintained. Outer container terminal Dox1 to Do
A pulse voltage having a peak value of 15 V was applied between the device electrodes 2 and 3 through xm and Doy1 to Doyn to perform an activation process.

In this manner, the forming and the activating processes were performed to form the gaps 5 as shown in FIG.
Next, the gas was evacuated to a pressure of about 10 ^-6 Torr, and an exhaust pipe (not shown) was welded by heating with a gas burner to seal the envelope 69.

Finally, in order to maintain the pressure after sealing, a getter treatment was performed by a high-frequency heating method.

In the image display device of the present invention completed as described above, each of the electron-emitting devices has a terminal Dox1 outside the container.
A scanning signal and a modulation signal are applied from signal generation means (not shown) through Doxm, Doy1 to Doyn, respectively, to emit electrons, and a voltage of 5 kV or more is applied to a metal back 66 or a transparent electrode (not shown) through a high voltage terminal 68. An image was displayed by applying a high voltage, accelerating the electron beam, colliding the electron beam with the fluorescent film 65, and exciting and emitting light.

The image display device of this example was able to display a good image stably over a long period of time at a luminance (about 150 fL) sufficiently satisfactory for a television.

(Embodiment 2) The basic structure of an electron source substrate according to this embodiment is the same as that of the first embodiment. Each content of each element contained in the form of steps -a-cleaned potassium glass (hereinafter _{oxides, SiO 2: 69%, Al} 2 O
_{3: 1%, K 2 O} : 18%, MgO: 4%, CaO: 8
%) On the substrate 1, 5 nm thick Ti,
Pt having a thickness of 50 nm is sequentially deposited. Thereafter, the patterns of the device electrodes 2 and 3 are formed of photoresist, the Pt / Ti deposited layer other than the pattern of the device electrodes 2 and 3 is removed by dry etching, and finally the photoresist pattern is removed. 2 and 3 are formed.

Step-b On the substrate 1 on which the device electrodes 2 and 3 are formed, a pattern of the wiring 6 is formed using an Ag paste by screen printing, dried, baked at 500 ° C., and formed into a desired shape of Ag. Is formed.

Step-c Next, a pattern of the interlayer insulating layer 8 is formed by screen printing using a glass paste.
Baking. In order to obtain sufficient insulating properties, printing, drying, and firing of the glass paste are repeated again to form the interlayer insulating layer 8 of glass having a desired shape.

Step-d The pattern of the upper wiring 7 is formed by screen printing using an Ag paste so as to intersect with the lower wiring 6 at the portion where the interlayer insulating layer 8 is formed, dried, and fired at 500 ° C. Then, an upper wiring 7 of a desired shape made of Ag is formed. Through the above steps, a substrate in which the element electrodes 2 and 3 are connected in a matrix by the wirings 6 and 7 can be formed.

Step-e Next, a conductive thin film 4 is formed so as to extend between the gaps between the device electrodes 2 and 3. The conductive thin film 4 is formed by applying an organic palladium solution to a desired position by an inkjet method, and performing a heating and baking treatment at 350 ° C. for 30 minutes. Thus, it is composed of fine particles containing PdO as a main component, and has a film thickness of about 1
A conductive thin film 4 having a thickness of 0 nm is obtained. Through the above steps, the lower wiring 6, the interlayer insulating layer 8, the upper wiring 7, the device electrodes 2, 3 and the conductive thin film 4 were formed on the base 1, and an electron source substrate was manufactured.

Thereafter, an image forming apparatus was constructed using the electron source substrate of the present embodiment in the same manner as in the first embodiment. Even in the image display apparatus of the present embodiment, the luminance was satisfactory with a satisfactory luminance for a television. Images could be displayed stably for a long time.

(Embodiment 3) The basic structure of an electron source substrate according to the present embodiment is the same as in Embodiments 1 and 2. Each content of each element contained in the form of steps -a cleaned cesium glass (hereinafter _{oxides, SiO 2: 70%, Al} 2 O
_{3: 1%, Cs 2 O} : 15%, MgO: 4%, CaO:
10%) A 5 nm-thick T
i, Pt having a thickness of 50 nm is sequentially deposited. Thereafter, the patterns of the device electrodes 2 and 3 are formed of photoresist, the Pt / Ti deposited layer other than the pattern of the device electrodes 2 and 3 is removed by dry etching, and finally the photoresist pattern is removed. 2 and 3 are formed.

Step-b On the substrate 1 on which the device electrodes 2 and 3 are formed, a pattern of the wiring 6 is formed using an Ag paste by screen printing, dried, baked at 500 ° C., and formed into a desired shape of Ag. Is formed.

Step-c Next, a pattern of the interlayer insulating layer 8 is formed by screen printing using a glass paste.
Baking. In order to obtain sufficient insulating properties, printing, drying, and firing of the glass paste are repeated again to form the interlayer insulating layer 8 of glass having a desired shape.

Step-d The pattern of the upper wiring 7 is formed by screen printing using an Ag paste so as to intersect with the lower wiring 6 at the portion where the interlayer insulating layer 8 is formed, dried, and fired at 500 ° C. Then, an upper wiring 7 of a desired shape made of Ag is formed. Through the above steps, a substrate in which the element electrodes 2 and 3 are connected in a matrix by the wirings 6 and 7 can be formed.

Step-e Next, the conductive thin film 4 is formed so as to extend between the gaps between the device electrodes 2 and 3. The conductive thin film 4 is formed by applying an organic palladium solution to a desired position by an inkjet method, and performing a heating and baking treatment at 350 ° C. for 30 minutes. Thus, it is composed of fine particles mainly composed of PdO, and has a film thickness of about 1
A conductive thin film 4 having a thickness of 0 nm is obtained.

Through the above steps, the lower wiring 6, the interlayer insulating layer 8, the upper wiring 7, the device electrodes 2, 3 and the conductive thin film 4 were formed on the base 1, and an electron source substrate was manufactured.

Thereafter, as in Embodiments 1 and 2, an image forming apparatus was constructed using the electron source substrate of this embodiment. Even in the image display apparatus of this embodiment, the luminance was sufficiently high for a television. A good image could be stably displayed for a long time.

Example 4 In this example, the same steps as in Example 2 were performed except that a glass substrate in which the alkali metal in the substrate was changed from 18% potassium to 2% sodium and 16% potassium. It is a thing. Steps -a to e A cleaned sodium / potassium-containing glass (where the content of each element contained in the following oxide form is SiO ₂ :
_{69%, Al 2 O 3:} 1%, Na 2 O: 2%, K 2 O:
(16%, MgO: 4%, CaO: 8%) The same process as in Example 3 was performed using the base 1, and the wiring 6, the interlayer insulating layer 8, the upper wiring 7, the element electrodes 2, 3 were formed on the base 1. Then, a conductive thin film 4 was formed to produce an electron source substrate.

After sealing was performed in the same manner as in Example 1, the atmosphere in the completed glass container was evacuated by a vacuum pump through an exhaust pipe (not shown), and after reaching a sufficient degree of vacuum, the container was evacuated. External terminals Dox1 to Doxm and Doy1 to Doy
With n, a voltage was applied to the device electrodes 2 and 3 to form the conductive thin film 4. At this time, there was some variation in the voltage value at which the forming occurred, but this was not a problematic level.

Thereafter, the entire glass container was heated at 200 ° C. for 2 hours while evacuating with a vacuum pump.
Since the conductive thin film 4 containing dO as a main component was not sufficiently thermally reduced, heating was further performed for 8 hours. As a result, the thermal reduction proceeded to form a film containing Pd as a main component.

Next, the exhaust was continued until the pressure in the panel reached the order of 10 ⁻⁸ Torr, and then the organic substance was injected into the panel from the exhaust pipe of the panel so that the total pressure became 1 × 10 ⁻⁶ Torr. Introduced and maintained. Outer container terminal Dox1 to Do
A pulse voltage having a peak value of 15 V was applied between the device electrodes 2 and 3 through xm and Doy1 to Doyn to perform an activation process.

Thus, the gap 5 was formed by performing the forming and activating processes.

After that, as in Embodiments 1 to 3, an image forming apparatus was constructed using the electron source substrate of this embodiment, and the image display apparatus of this embodiment also had a luminance which was sufficiently satisfactory as a television. A good image could be stably displayed for a long time.

Comparative Example 1 In this comparative example, the same steps as in Example 4 were performed except that a glass substrate in which the alkali metal in the substrate was changed from 18% potassium to 3% sodium and 15% potassium was used. It is a thing.

Steps a to e: Cleaned sodium / potassium-containing glass (content of each element contained in the following oxide form is SiO ₂ :
_{69%, Al 2 O 3:} 1%, Na 2 O: 3%, K 2 O:
(15%, MgO: 4%, CaO: 8%) Using the base 1, the same process as in Example 4 was performed, and the wiring 6, the interlayer insulating layer 8, the upper wiring 7, the element electrodes 2, 3 and the conductive layers were formed on the base 1. The conductive thin film 4 was formed, and an electron source substrate was manufactured.

After sealing was performed in the same manner as in Example 1, the atmosphere in the completed glass container was evacuated with a vacuum pump through an exhaust pipe (not shown). External terminals Dox1 to Doxm and Doy1 to Doy
With n, a voltage was applied to the device electrodes 2 and 3 to form the conductive thin film 4. At this time, there was considerable variation in the voltage value at which forming occurred, and some elements could not be formed.

Thereafter, the entire glass container was heated at 200 ° C. for 10 hours while evacuating with a vacuum pump.
The conductive thin film 4 mainly composed of PdO was not sufficiently thermally reduced.

Next, the exhaust was continued until the pressure in the panel reached the order of 10 ^-8 Torr, and then the organic substance was injected into the panel from the exhaust pipe of the panel so that the total pressure became 1 × 10 ^-6 Torr. Introduced and maintained. Outer container terminal Dox1 to Do
xm and the element electrodes 2 and 3 through Doy1 to Doyn.
In the meantime, a pulse voltage of a peak value of 15 V was applied to perform an activation process. In this way, the gap 5 was formed by performing the forming and the activation processing.

Thereafter, an image forming apparatus was constructed using the electron source substrate of the present embodiment in the same manner as in Examples 1 to 4. The image display apparatus of this comparative example had a somewhat dark impression and had many variations. This resulted in a rough image.

Comparative Example 2 In this comparative example, the same steps as in Examples 1 to 4 were performed, except that a soda-lime glass substrate (17% sodium) was used as the substrate 1. Processes -a to e Cleaned soda lime glass (content of each element contained in the following oxide form is SiO ₂ : 70%, Al
₂ O ₃ : 1%, Na ₂ O: 17%, MgO: 4%, Ca
O: 8%) The same process as in Examples 1 to 4 is performed using the base 1, and the lower wiring 6, the interlayer insulating layer 8, the upper wiring 7, the device electrodes 2 and 3, and the conductive thin film 4 are formed on the base 1. Was formed to produce an electron source substrate.

After sealing was performed in the same manner as in Example 1, the atmosphere in the completed glass container was evacuated by a vacuum pump through an exhaust pipe (not shown), and after reaching a sufficient degree of vacuum, the container was evacuated. External terminals Dox1 to Doxm and Doy1 to Doy
With n, a voltage was applied to the device electrodes 2 and 3 to form the conductive thin film 4. At this time, there was considerable variation in the voltage value at which forming occurred, and there were many elements that could not be formed.

Thereafter, the entire glass container was heated at 200 ° C. for 10 hours while evacuating with a vacuum pump.
The conductive thin film 4 mainly composed of PdO was not sufficiently thermally reduced.

Next, after exhausting was continued until the pressure in the panel reached the level of 10 ^-8 Torr, an organic substance was injected into the panel from the exhaust pipe of the panel so that the total pressure became 1 × 10 ^-6 Torr. Introduced and maintained. Outer container terminal Dox1 to Do
A pulse voltage having a peak value of 15 V was applied between the device electrodes 2 and 3 through xm and Doy1 to Doyn to perform an activation process. At this time, a large variation in the finally obtained current value was observed.

As described above, the gap 5 was formed by performing the forming and activation processes.

Thereafter, an image forming apparatus was constructed using the electron source substrate of the present embodiment in the same manner as in Examples 1 to 4, and the image display apparatus of this comparative example was very difficult to see because of the large variations. It became an image.

[0140]

As described above, according to the present invention, a high-performance electron source substrate can be realized by forming an electron source substrate using a substrate having a low sodium content. Further, a flat screen image forming apparatus having a large screen capable of holding a good image for a long time, for example, a color flat television can be realized by using the apparatus.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of an electron source substrate of the present invention.

2A is a bird's-eye view of the vicinity of an electron-emitting device of the electron source substrate of the present invention, and FIG. 2B is a cross-sectional view of the vicinity of the electron-emitting device of the electron source substrate of the present invention.

FIG. 3 is a view for explaining a basic method of manufacturing an electron source substrate according to the present invention.

FIG. 4 is a diagram for explaining a basic method for manufacturing an electron source substrate according to the present invention.

FIG. 5 is a diagram showing an example of a voltage waveform in a forming process according to the present invention.

FIG. 6 is a diagram illustrating a basic configuration of an image forming apparatus according to the present invention.

FIG. 7 is a diagram illustrating a fluorescent film used in the image forming apparatus of FIG. 6;

FIG. 8 is a diagram showing a configuration of a basic surface conduction electron-emitting device.

FIG. 9 is a view for explaining a basic method of manufacturing the surface conduction electron-emitting device.

FIG. 10 is a diagram of a measurement and evaluation device used for evaluating characteristics of a surface conduction electron-emitting device.

FIG. 11 is a diagram showing a typical example of a relationship among an emission current, an element current, and an element voltage of a surface conduction electron-emitting device.

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

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

FIG. 14 is a plan view showing a configuration of a conventional electron source substrate.

FIG. 15 is a bird's-eye view showing a configuration of a conventional electron source substrate.

[Explanation of symbols]

1: substrate, 2, 3: device electrode, 4: conductive thin film, 5: electron emitting portion, 6, 7: wiring, 8: interlayer insulating layer, 30: device flowing through conductive thin film between device electrodes 2, 3 Ammeter for measuring current If, 31: element voltage Vf applied to electron-emitting device
32: an ammeter for measuring the emission current Ie emitted from the electron emission portion of the device, 33:
A high-voltage power supply for applying a voltage to the anode electrode 34;
4: anode electrode, 61: electron source substrate, 62: rear plate, 63: outer frame, 64: face plate substrate, 6
5: fluorescent film, 66: metal back, 67: face plate, 68: high voltage terminal, 69: vacuum envelope, 71: black conductor, 72: phosphor, 81: electron emitting element, 91: substrate.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuya Miyazaki, 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Tomoko Maruyama 3-30-2 Shimomaruko, Ota-ku, Tokyo 4G059 AA08 AC11 DA03 5C031 DD09 DD17 5C036 EF01 EF06 EF09 EG02 EG12 EH26

Claims (13)

[Claims] An electron source substrate comprising a substrate and a plurality of electron-emitting devices each comprising a pair of device electrodes and a conductive thin film having a gap, wherein the substrate has a sodium content of 2% or less. An electron source substrate, comprising: 2. The electron source substrate according to claim 1, wherein said substrate is a glass substrate. 3. The electron source substrate according to claim 1, wherein the conductive thin film mainly contains Pd, PdO, or a mixture thereof. 4. The electron source substrate according to claim 1, wherein said conductive thin film has a sodium content of 0.1% or less. 5. The method according to claim 1, wherein the glass substrate is alkali-free glass containing substantially no alkali metal element, glass having a low alkali metal element content, or glass containing a large amount of alkali metal element and having a low sodium content. The electron source substrate according to claim 2, wherein: 6. The electron source substrate according to claim 2, wherein the glass substrate is a glass not containing quartz glass. 7. The electron source substrate according to claim 6, wherein the glass containing a large amount of an alkali metal element and having a low sodium content contains potassium, rubidium, or cesium. 8. The electron source substrate according to claim 1, wherein said electron-emitting device is a surface conduction electron-emitting device. 9. The electron source substrate according to claim 1, wherein the electron emission portion has carbon, a carbon compound, or a deposit containing carbon or a carbon compound as a main component. 10. An electron according to claim 1, wherein device electrodes at both ends of each of said electron-emitting devices are connected to a metal wiring, and electrons are emitted in accordance with an input signal. Source substrate. 11. The device according to claim 10, further comprising a plurality of rows of the electron-emitting devices in which a plurality of the electron-emitting devices are arranged in parallel, and further comprising a modulating means for modulating the input signal. Electron source substrate. 12. A pair of element electrodes of said electron-emitting device are connected to said X-direction metal wiring and said X-direction metal wiring at each intersection of said m X-direction metal wirings and said n Y-direction metal wirings electrically insulated from each other. 12. The electron source substrate according to claim 11, wherein the electron-emitting devices are connected to the Y-direction metal wiring and the electron-emitting devices are arranged in a matrix. 13. An apparatus for forming an image based on an input signal, wherein the apparatus comprises at least an image forming member and the electron source substrate according to any one of claims 1 to 12. Forming equipment.