JP2002216614A - Electron source substrate and its manufacturing method and image generator using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a wiring metal from degradation and variation in an electron emission characteristic of its electron emission device due to its diffu sion into a conductive thin film without contacting to the conductive thin film. SOLUTION: The image generator is provided with an electron emission device 11 containing a pair of electrodes 2/3 located via a sodium diffusion control layer 9 and wires 6/7 respectively-connected with the electrodes 2/3 on its basic substance 1. At least part of the component for these electrodes 2/3 is made of a noble metallic element having its own standard single electrode potential lower than that of the component forming the wires 6/7, while the wires 6/7 are composed of either any one of metals such as Ag, Cu, Au or any alloy containing any one of these metals. Additionally the conductive thin film 4 containing an electron emitting section 5 is composed of either Pd, PdO, or a mixture of these elements.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron source substrate using an electron-emitting device, a method for manufacturing the same, 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 number of cold cathode electron-emitting devices are formed and an anode substrate provided with a transparent electrode and a phosphor are parallelly opposed 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,
Devices using a field emission type electron-emitting device are described in, for example, I.
Brodie, "Advanced technology"
gy: flat cold-cathode CRT
s ", Information Display, 1
/ 89, 17 (1989).

A device using a surface conduction electron-emitting device is disclosed, for example, in US Pat. No. 5,066,883. A flat-type electron beam display panel is a widely used cathode ray tube (cathode ray tube).
tube (CRT) display device, a lighter weight, and a larger screen can be achieved, and other flat display devices such as a flat display panel using a liquid crystal, a plasma display, and an electroluminescent display. It is possible to provide a higher-luminance, higher-quality image than a panel.

In particular, surface conduction electron-emitting devices have a simple structure and are easy to manufacture, and a large number of devices over a large area can be manufactured without going through a complicated manufacturing process utilizing photolithography as in a field emission electron-emitting device. There is an advantage that an electron source substrate in which elements are arranged and formed can be manufactured.

FIGS. 10 and 11 show Japanese Patent Application Laid-Open No. 6-34263.
6 shows an example of an electron source substrate using a surface conduction electron-emitting device disclosed in Japanese Patent Application Laid-Open No. 6-206. FIG.
Shows a plan view of a part of the electron source. Here, 7 is an upper wiring, 6 is a lower wiring, 101 is a surface conduction electron-emitting device, 8
Is an interlayer insulating layer. FIG. 10 is a perspective view of the surface conduction electron-emitting device 101 of FIG. In FIG. 11, 1 is a substrate, 2 and 3 are electrodes, 4 is a conductive thin film having an electron emitting portion, 5 is an electron emitting portion, and electrodes 2 and 3 are shown.
Are connected to the corresponding lower wiring 6 and upper wiring 7, respectively.
The lower wiring 6 and the upper wiring 7 are electrically insulated by the interlayer insulating layer 8.

Here, a predetermined voltage as a scanning signal and information is sequentially applied to the upper wiring 7 and the lower wiring 6 arranged in a matrix, respectively, thereby selecting a predetermined electron-emitting device 101 located at the intersection of the matrix. Can be driven.

[0007] The electron source substrates arranged in such 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. 8-180797 discloses a manufacturing method for forming a wiring and an interlayer insulating layer applicable to an electron source substrate by a screen printing method. For other members, for example, Japanese Patent Application Laid-Open No. 9-17333 discloses a manufacturing method in which electrodes are formed by an offset printing method or the like, and a manufacturing method in which a conductive thin film is formed by an inkjet method is disclosed. JP-A-9-6
No. 9,334, for example. By using these printing techniques, a large-area electron source substrate can be easily manufactured.

Next, the surface conduction electron-emitting device will be described. The surface conduction electron-emitting device utilizes a phenomenon in which electron emission occurs when a current flows in a small-area conductive thin film formed on a substrate in parallel with the film surface. As a conventional surface conduction electron-emitting device, a device using a SnO ₂ thin film [M. I. Elinson, RadioEn
g. Electron Phys. , 10,1290
(1965)], [G. Dittmer: “Thin
Solid Films ", 9, 317 (197
2)], an In ₂ O ₃ / SnO ₂ thin film [M. H
artwell and C.I. G. FIG. Fonstad:
"IEEE Trans. ED Conf.", 51
9 (1975)], using a carbon thin film [Hisashi Araki]
Others: Vacuum, Vol. 26, No. 1, p. 22, p. 22 (1983)], and the like.
Japanese Patent Application No. 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, it is general that the electron-emitting portion 5 is formed on the conductive thin film 4 by an energization treatment called forming or the like. The forming is a process of applying a voltage to both ends of the conductive thin film 4 to form a crack (gap) in a part of the conductive thin film 4.

Further, as disclosed in, for example, Japanese Patent Application Laid-Open No. 7-235255, a process called an activation process is performed on the element after forming, so that better electron emission can be obtained. The activation step can be performed by applying a voltage to the device in an atmosphere containing a carbon compound-based gas, similarly to the forming treatment.
By this treatment, a film composed of carbon and / or a carbon compound is deposited on the device from the carbon compound present in the atmosphere, and the device current _If and the emission current _Ie are significantly increased.

The 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, a large area image forming apparatus, for example, a large screen flat panel display is manufactured by manufacturing a large number of surface conduction electron-emitting devices on a large area substrate using a printing technique. Can be realized.

[0014]

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

As described above, when a wiring is formed by a method such as screen printing using an Ag paste or the like as the wiring material, if the heat treatment process is repeated, the wiring is transferred to the electrode or the interface between the substrate and the electrode to form the substrate. Diffusion in the direction parallel to the surface may occur.

Due to such diffusion, the wiring material may come into contact with the conductive thin film. Here, when a heat treatment is further performed or an electric field for driving is applied, the wiring metal and the conductive thin film are mixed by migration due to the heat or the electric field, and the electron emission element maintains the original electron emission characteristics. Becomes difficult, causing deterioration and fluctuation of characteristics.
Therefore, it is necessary to suppress the diffusion of the wiring metal into the conductive thin film as much as possible.

An object of the present invention is to solve the above-mentioned technical problem, to suppress the contact of the wiring metal with the conductive thin film, and as a result, the electron emission of the electron-emitting device due to the diffusion of the wiring metal into the conductive thin film. An object of the present invention is to provide a high-performance electron source substrate in which deterioration and fluctuation of characteristics are suppressed, and a method of manufacturing the same. Another object of the present invention is to provide a large-screen flat-type image forming apparatus capable of holding a good image for a long time by using such an electron source substrate.

[0018]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, that is, the deterioration of the characteristics of the electron-emitting device due to the diffusion of the wiring metal into the conductive thin film. This is a configuration of

That is, a first aspect of the present invention is an electron source substrate having, on a substrate, an electron-emitting device having a pair of electrodes, and a wiring connected to the electrodes, wherein the electrodes are composed of constituent elements Wherein at least a part of the noble metal element is made of a noble metal element, and the standard monopolar potential of the noble metal element is lower than that of the element constituting the wiring.

A first feature of the present invention is that the wiring is made of any one of a metal of Ag, Cu, and Au, and an alloy containing any of these metals. "The wiring is at least a part of the constituent elements of Ag", and "the electrode is made of at least one element selected from Ru, Rh and Os at a portion in contact with the wiring". May be included. The second aspect of the present invention is
An electron source substrate including, on a base, an electron-emitting device having a pair of electrodes and a wiring connected to the electrodes, wherein the wiring is any one of Ag, Cu, and Au, or An electron source substrate comprising: an alloy containing any one of the metals; and the electrode includes one or more elements selected from Ru, Rh, and Os. The first or second electron source substrate according to the present invention may be configured such that “the base is made of silica at a portion in contact with at least one of the electrode and the wiring”; "A conductive film having an electron-emitting portion in a part thereof";"the conductive thin film having an electron-emitting portion is made of any of Pd, PdO, and a mixture thereof"; Is a surface conduction electron-emitting device "," the plurality of electron-emitting devices are arranged and emits electrons in response to an input signal ", and" the plurality of electron-emitting devices are arranged in parallel and individually "Having a plurality of rows of electron-emitting devices having both ends connected to the wiring, and having a modulating means for applying a modulation signal to the electron-emitting devices." X "A pair of electrodes of the electron-emitting device were connected to the direction wiring and n number of Y-direction wirings, and the electron-emitting devices were arranged in a matrix";"the base was made of non-alkali glass"; Forming a sodium diffusion control layer on the surface of the base, and disposing the electron-emitting device and the wiring on the sodium diffusion control layer. "

According to a third aspect of the present invention, there is provided a method for manufacturing an electron source substrate, wherein the wiring is formed by printing a metal paste and heating and baking. In this case, the method may include a step of performing an activation process on the electron-emitting device in an atmosphere containing the carbon compound, and a step of discharging a residue of the carbon compound introduced during the activation process. .

A fourth aspect of the present invention is an image forming apparatus for forming an image based on an input signal, and is an image forming apparatus comprising at least an image forming member and any one of the above-mentioned electron source substrates. According to another aspect of the invention, there is provided an image forming apparatus in which an electron source substrate and a substrate having an image forming member are arranged to face each other, wherein the electron source substrate is any one of the above electron source substrates. It may be.

The present invention is effective when a wiring is formed by printing as an electron source substrate. Since the wiring metal is hardly diffused into the conductive thin film, deterioration of the electron emission characteristics can be effectively prevented.

[0024]

Embodiments of 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 an electron source substrate according to an embodiment of the present invention, and shows only a part of the electron source substrate. FIG.
2 is an enlarged bird's-eye view of one electron-emitting device of the electron source substrate shown in FIG. FIG. 3 is a diagram showing A in FIG.
It is -A 'sectional drawing. In the electron source substrate 61 shown in FIGS. 1, 2 and 3, reference numeral 1 denotes a base, reference numerals 2 and 3 denote electrodes, reference numeral 4 denotes a conductive thin film, reference numeral 5 denotes an electron emitting portion, and reference numerals 6 and 7 denote electrodes 2 and 2, respectively.
The wiring connected to 3, 8 is an interlayer insulating layer for electrically insulating the wiring 6 and the wiring 7, and 9 is a sodium diffusion suppressing layer. Reference numeral 11 denotes an electron-emitting device. The electron-emitting device 11 of the embodiment shown here includes a pair of electrodes 2 and 3, a conductive thin film 4, an electron-emitting portion 5, and the like on the base 1 via the sodium diffusion suppressing layer 9. . However, this sodium diffusion suppressing layer is not always necessary. That is, the present invention is satisfied even in a mode in which electron-emitting devices and wirings are directly arranged on the substrate 1. The wiring 6,
Reference numeral 7 denotes a Y-direction wiring in the light of the coordinates in FIG.
The wiring may be called an X-direction wiring, or may be called a lower wiring or an upper wiring, respectively, depending on the positional relationship with the interlayer insulating layer 8.

As the base 1, soda lime glass, which is generally called blue plate glass, is preferably used because it is inexpensive. However, sodium contained in soda lime glass is partially replaced with potassium to increase the strain point. Strain point glass can be used. When a substrate containing sodium such as the above-mentioned soda lime glass is used, it is preferable to use the above-mentioned sodium diffusion suppressing layer 9 because sodium may adversely affect the electron-emitting device. Alternatively, an alkali-free glass substrate used for a liquid crystal panel or the like can be used. In this case, the sodium diffusion suppressing layer 9 need not be formed. The electron source substrate 61 and the image forming apparatus using the same according to the present embodiment are subjected to several heat treatments during the manufacturing process. The material of the base 1 may be selected according to the setting of the heat treatment temperature at this time and the allowable value of the distortion of the substrate at the heat treatment temperature.

The sodium diffusion suppressing layer 9 has a role of suppressing the diffusion of sodium from the substrate 1 to the electron-emitting device 11 and a role of making it difficult to transmit heat generated when a current flows through the electron-emitting device 11 to the substrate 1. Can be. As the sodium diffusion suppressing layer 9, for example, a coating layer containing silica as a main component can be preferably used. Here, silica means SiO ₂ , SiO, or a mixture thereof. Above all, an SiO ₂ layer or a layer made of phosphorus-doped silica glass (PSG) containing several wt% of phosphorus is more preferably used as a sodium diffusion suppressing layer.
These sodium diffusion suppressing layers have a thickness of 500 nm.
The above formation is preferable because diffusion of sodium can be effectively stopped.

As the material of the opposed electrodes 2 and 3, it is preferable to use a material which has stable conductivity even after a heat treatment step and does not cause thermal diffusion of the metal constituting the wirings 6 and 7.
That is, it is preferable to use a metal that prevents the metal constituting the wirings 6 and 7 from being ionized and diffused without losing conductivity even in the heat treatment step in the atmosphere. Therefore, the electrodes 2 and 3 are
A material is used in which some or all of the constituent metals are made of a noble metal element and the standard monopolar potential of the noble metal element is lower than that of the elements forming the wirings 6 and 7. For example, when a part or all of the constituent elements of the wirings 6 and 7 are Ag, Ru, Rh,
Alternatively, a metal or alloy composed of one or more elements selected from Os is preferably used. The electrodes 2, 3
May be a laminated structure composed of a plurality of layers. In this case, R
What is necessary is just to make it the metal or alloy which consists of one or more types of elements selected from u, Rh, or Os. Note that the thickness of the electrodes 2 and 3 is preferably about several tens of nm, since it has sufficient conductivity and the step coverage of the conductive thin film 4 is good.

Since the thermal stability of the conductive thin film 4 is an important parameter that governs the life of the electron emission characteristics, it is desirable to use a material having a higher melting point as the material of the conductive thin film 4. However, usually, the higher the melting point of the conductive thin film 4 is, the more difficult it is to carry out the energization forming, which will be described later. Further, the resulting electron-emitting portion 5 may have a problem that the applied voltage (threshold voltage) at which electrons can be emitted increases. Therefore, as the material of the conductive thin film 4, it is preferable to select a material having a moderately high melting point and capable of forming a good electron-emitting portion 5 with a relatively low forming power.

Under the above-mentioned conditions, PdO can easily form a thin film by baking an organic palladium compound in the air, and since it is a semiconductor, it has relatively low electric conductivity and low power required for forming. At the time of formation or thereafter, it can be easily reduced to metal palladium, so that the film resistance can be reduced. Therefore, it can be used as a material suitable for the conductive thin film 4. The film thickness depends on the step coverage for the electrodes 2 and 3 and the electrodes 2 and 3
The resistance is set in consideration of the resistance value between them, forming conditions described later, and the like.

The electron emitting portion 5 includes a gap (crack) formed on a part of the conductive thin film 4. This gap depends on the manufacturing method such as the thickness of the conductive thin film 4 and the energization processing conditions described later.

Further, a film (carbon film) made of carbon and / or a carbon compound is disposed in the electron emitting portion 5 through an activation step described later.

The wirings 6 and 7 are for supplying power to a plurality of electron-emitting devices 11 as shown in FIG. The m X-direction wirings 7 are DX1, DX2,..., DXm, n
, DYn, DY2,..., DYn
The material, the film thickness, the wiring width, and the like are set so that a substantially uniform voltage is supplied to each of the electron-emitting devices 11. An interlayer insulating layer 8 is provided between the m X-directional wirings 7 and the n Y-directional wirings 6 and electrically separated to form a matrix wiring (where m and n are:
Both are positive integers).

The wirings 6 and 7 are preferably made of a metal having stable conductivity even after a heat treatment process, but in particular, a printing method capable of forming a large-area substrate at low cost is preferably used. A metal film obtained by forming a pattern by screen printing using a metal paste and heat-treating is suitable for forming a wiring having a large resistance of several microns or more and a small resistance over a large area. Therefore, a paste of Ag, Cu, or Au from which a printable metal paste can be obtained relatively inexpensively is used for the metal paste. Then, Ag, Cu, or Au obtained by heat-treating it is preferably used as a wiring material. Further, a mixture of these metal pastes or the like may be used.

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. Further, a thick glass layer obtained by printing a glass paste is used. In the configuration shown in FIG. 1, that is, the configuration of the matrix arrangement, a scanning signal applying unit (not shown) for applying a scanning signal for selecting a row of the electron-emitting devices 11 arranged in the X direction is provided to the X-direction wiring 7. The Y-direction wiring 6 is connected to a modulation signal generator (not shown) for modulating each column of the electron-emitting devices 11 arranged in the Y-direction according to an input signal. The driving voltage applied to each electron-emitting device 11 is supplied as a difference voltage between a scanning signal and a modulation signal applied to the device, and individual devices can be selected and driven independently using a simple matrix wiring. It can be.

On the other hand, in addition to the above, each of a large number of electron-emitting devices 11 arranged in parallel is connected at both ends, and a large number of rows of the electron-emitting devices 11 are arranged. There is a ladder-like arrangement in which electrons from the electron-emitting device 11 are controlled and driven by a control electrode disposed above the element 11, but the present invention is not particularly limited by these arrangements.

As described above, in the present embodiment, the wirings 6 and 7 are connected to the electrodes 2 and 3. Here, electrodes 2,
For 3, a material is selected in which some or all of the constituent elements are made of a noble metal element, and the standard monopolar potential of the noble metal element is lower than the elements forming the wirings 6 and 7. When the electrodes 2 and 3 are formed of Pt or a noble metal such as Au and the wires 6 and 7 are made of Ag, the metal constituting the wires 6 and 7, that is, the electrode 2 made of the above-mentioned noble metal is Ag. 3 and the phenomenon of diffusion into the conductive film 4. The exact mechanism of this spread is not clear,
It is considered that the metal forming the wirings 6 and 7 diffuses once into the metal forming the electrodes 2 and 3 and then diffuses into the conductive film 4 via the electrodes 2 and 3. Note that the standard monopolar potentials of Pt and Au are higher than Ag. On the other hand, electrodes 2, 3
Is formed of a noble metal of Ru, Rh, or Os, and the wirings 6, 7 are made of Ag, the wiring metal hardly diffuses into the electrodes 2, 3, and the interface diffusion hardly occurs. This is because the standard monopolar potential of the noble metal of Ru, Rh, or Os is smaller than that of Ag, and it is to effectively suppress the ionization of Ag and diffusion into the electrodes 2 and 3. is there.

As described above, when the metal forming the wirings 6 and 7 is diffused, the metal may eventually reach the conductive thin film 4 and further reach the electron emitting portion 5. Here, when an electric field for driving the electron-emitting device 11 is applied,
Since the metal constituting the wirings 6 and 7 and the conductive thin film 4 may be mixed and alloyed or the quality of the film may be changed due to migration due to an electric field or heat during driving, the electron emission element 11 emits the original electron. It becomes difficult to maintain the characteristics, which may cause deterioration or fluctuation of the characteristics. Therefore, as in the present embodiment, the standard monopolar potential of the noble metal element in the electrodes 2 and 3 is set lower than that of the elements forming the wirings 6 and 7, so that the metal forming the wirings 6 and 7 can be reduced. Can be effectively suppressed from being ionized and diffused into the electrodes 2 and 3, and stable electron emission characteristics can be maintained for a long time.

Now, various methods can be considered as a method of manufacturing the electron source substrate according to the embodiment of the present invention. Here, one example is shown in FIG.

Hereinafter, the manufacturing method will be described step by step with reference to FIG.
A description will be given based on FIGS. 2, 3, and 4.

(1) After sufficiently washing the substrate 1 with a detergent, pure water and an organic solvent, a sodium diffusion suppressing layer 9 is formed by a sputtering method or the like (FIG. 4A). Here, since a sodium-containing substrate was used as the substrate 1,
Although the sodium diffusion suppressing layer 9 is formed, the sodium diffusion suppressing layer 9 is not always required.

(2) Subsequently, after the above-mentioned electrode material of the present invention is deposited on the substrate 1 by a vacuum deposition method, a sputtering method, or the like, the electrodes 2 and 3 are formed by photolithography (FIG. b)). The electrodes 2 and 3 are formed as follows.
It can also be formed using a printing technique such as offset printing.

(3) On the substrate 1 on which the electrodes 2 and 3 are formed,
A conductive paste pattern is formed by a screen printing method, and the conductive paste pattern is baked to form a lower wiring 6 made of metal (FIG. 4C). As the conductive paste, a paste containing a conductive material made of any one of Ag, Cu, and Au and an alloy containing any one of these metals was used.

(4) Further, an interlayer insulating layer 8 is formed at a desired position on the lower wiring 6, that is, at a position crossing the upper wiring 7 to be formed in a subsequent step (FIG. 4D). 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. The interlayer insulating layer 8
If it is desired to increase the film thickness in order to provide sufficient insulation, the above printing and baking can be repeated a desired number of times.

(5) Subsequently, the upper wiring 7 is formed so as to cross on the interlayer insulating layer 8 formed on the lower wiring 6 (FIG. 4E). The upper wiring 7 can also be formed by forming a conductive paste pattern from the same material as the lower wiring 6 and firing the conductive paste pattern.

(6) The electrode 2 provided on the base 1
A film of an organometallic compound is formed by applying and drying a solution of an organometallic compound between the substrate and the electrode 3. Thereafter, the organometallic compound film is heated and baked, and is patterned by lift-off, etching, or the like to form a conductive thin film 4 (FIG. 4F). 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.

(7) Subsequently, a voltage application process called forming is performed between the electrodes 2 and 3, that is, between the wirings 6 and 7, and a gap is formed in a part of the conductive thin film 4.

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, and T1 is 1 μs.
ec to 10 msec, T2 is 10 μsec to 100 ms
ec, the peak value of the triangular wave (peak voltage at the time of forming) is appropriately selected.

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 μsec to 10 msec.
c, T2 is set to 10 μsec to 100 msec, and the peak value of the triangular wave (the peak voltage at the time of forming) is increased by, for example, about 0.1 V steps. The forming process is performed at a voltage that does not locally break or deform the conductive thin film 4 during the forming pulse.
The device current is measured by inserting a pulse voltage of about 1 V, and the process ends when the current decreases below a predetermined value.

(8) Next, an activation process is performed on the electron-emitting device 11 for which the forming has been completed to form an electron-emitting portion 5 (FIG. 4G). The activation process is performed under an atmosphere containing a carbon compound, as in the above-described forming process.
This atmosphere is obtained by applying a voltage. The atmosphere is obtained by disposing the electron source substrate 61 in a vacuum vessel and introducing an appropriate carbon compound. When the vacuum envelope 69 (see FIG. 6) is formed using the electron source substrate 61 as in an image forming apparatus described later, the vacuum envelope 6 is used.
An activation treatment can be performed in 9 by introducing a carbon compound.

Organic substances are preferred as suitable carbon compounds.
In addition, as organic substances, alkanes, alkenes,
Alkyne fatty hydrocarbons, aromatic hydrocarbons, alcohols
Aldehydes, ketones, amines, nitriles
, Phenols, carboxyls, organic acids such as sulfonic acids, etc.
Specific examples include methane, ethane, and methane.
C such as Lopin_nH_{2n + 2}A saturated hydrocarbon represented by the formula
C _nH_2nUnsaturation represented by a composition formula such as
Japanese hydrocarbon, benzene, toluene, methanol, etano
, Formaldehyde, acetaldehyde, aceto
, Methyl ethyl ketone, methylamine, ethylamine
, Phenol, benzonitrile, acetonitrile, ants
Acids, acetic acid, propionic acid and the like can be used.

By this treatment, the organic substances existing in the atmosphere
A film made of carbon and / or carbon compound from a substance
(Carbon film) is deposited on the electron-emitting device 11,
Style I _f, Emission current I_eChanges significantly.
The end of the activation step is determined by the device current I_fAnd / or release
Output current I_eThe measurement is performed as appropriate while measuring. Note that the pulse width,
The pulse interval, pulse crest value, and the like are set as appropriate.

The carbon and carbon compound include, for example, graphite (including so-called HOPG, PG, and GC;
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. ), Amorphous carbon (refers to amorphous carbon and a mixture of amorphous carbon and the microcrystals of graphite).

(9) On the electron source substrate thus manufactured,
Preferably, the treatment is performed in a stabilization step. This step is
This is a step of exhausting residues of organic substances introduced during the activation process. The pressure in the vacuum vessel is 1.3 to 4.0 × 10
^-5 Pa or less, more preferably 1.3 × 10 ^-6 Pa 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 pumping device such as a sorption pump or an ion pump can be used. Further, when evacuating the inside of the vacuum vessel, 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 condition at this time is desirably 80 to 250 ° C., preferably 150 ° C. or more, and it is desirable to perform the heating for as long as possible. However, it is not particularly limited to this condition, and the size and shape of the vacuum vessel and the configuration of the electron source substrate This is performed under conditions appropriately selected according to various conditions such as the above.

It is preferable that the atmosphere during the driving after the stabilization step is performed is the same as the atmosphere after the above stabilization processing, but the present invention is not limited to this. However, even if the pressure itself slightly increases, sufficiently stable characteristics can be maintained.

By employing such a vacuum atmosphere, the deposition of new carbon or a carbon compound can be suppressed.
As a result, the element current _If and the emission current _Ie are stabilized.

The above is the manufacturing process of the electron source substrate according to the present invention. An example in which an image forming apparatus is formed by using the electron source substrate will be described below with reference to FIGS. FIG.
Is a basic configuration diagram of an image forming member of the image forming apparatus, and FIG. 7 is a diagram illustrating a fluorescent film.

In FIG. 6, reference numeral 61 denotes an electron source substrate on which a plurality of electron-emitting devices 11 are arranged; 62, a rear plate on which the electron source substrate 61 is fixed; 67, a glass substrate (rear plate substrate) 64; This is a face plate including a phosphor film 65 and a metal back 66. 63 is a support frame. The support frame 63 includes a rear plate 62,
The face plate 67 is connected using frit glass or the like. Reference numeral 69 denotes a vacuum envelope, for example, in a temperature range of 400 to 500 ° C.
By baking for more than a minute, it is configured by sealing.

The vacuum envelope 69 includes the face plate 67, the support frame 63, and the rear plate 62 as described above. The rear plate 62 is provided mainly for the purpose of reinforcing the strength of the electron source substrate 61. Therefore, if the electron source substrate 61 itself has sufficient strength, the separate rear plate 62 is unnecessary, and the support frame 63 is directly sealed to the electron source substrate 61, and the face plate 67, the support frame 63, and the The source container 61 may constitute the vacuum envelope 69.

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

FIG. 7 is a diagram showing a fluorescent film. Fluorescent film 6
In the case of a monochrome phosphor, a black conductor 71 called a black stripe or a black matrix shown in (a) or (b) depends on the arrangement of the phosphors in the case of a color phosphor film. And phosphor 72
It is composed of The purpose of providing the black stripes or the black matrix is to make the color separation between the respective phosphors 72 of the three primary color phosphors necessary for color display black so that mixed colors and the like are inconspicuous. The object is to suppress a decrease in contrast due to reflection of external light on the film 65. The material of the black stripe is not limited to a commonly used material containing graphite as a main component, as long as it is conductive and has little light transmission and reflection. As a method of applying the phosphor on the glass substrate 64, a precipitation method, a printing method, or the like is used regardless of monochrome or color.

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 acceleration voltage, and using the inside of the vacuum envelope 69. And protection of the phosphor 72 from damage due to the collision of the negative ions generated in the above. The metal back 66 can be manufactured by performing a smoothing process (usually called filming) on the inner surface of the fluorescent film 65 after manufacturing the fluorescent film 65, and then depositing Al using vacuum evaporation or the like. In order to further increase the conductivity of the fluorescent film 65, a fluorescent film 65
May be provided with a transparent electrode (not shown) on the outer surface side. When the above-mentioned sealing is performed, in the case of color, the phosphors of each color must correspond to the electron-emitting devices 11, so that it is necessary to perform sufficient alignment.

After the vacuum envelope 69 is evacuated to about 1.3 × 10 ⁻⁵ Pa through an exhaust pipe (not shown), sealing is performed. In addition, getter processing may be performed to maintain the degree of vacuum after sealing the vacuum envelope 69. this is,
Immediately before or after the sealing of the vacuum envelope 69, a getter disposed at a predetermined position (not shown) in the vacuum envelope 69 is heated by a heating method such as resistance heating or high-frequency heating, This is a process for forming a deposition film. Getter is usually B
a is a main component, and maintains a degree of vacuum of, for example, 1.3 × 10 ⁻³ Pa or 1.3 × 10 ⁻⁵ Pa by the adsorption action of the deposited film.

In the image forming apparatus according to the present embodiment completed as described above, a voltage is applied to each electron-emitting device 11 through external terminals Dox1 to Doxm and external terminals Doy1 to Doyn.
Electrons are emitted and the metal back 6
An image is displayed by applying a high voltage of several kV or more to 6 or a transparent electrode (not shown), accelerating the electron beam, causing the electron beam to collide with the fluorescent film 65, 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. For example, 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 forming apparatus.

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

[0067]

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 structure of an electron source substrate according to this embodiment is the same as that shown in FIGS. 1, 2 and 3. FIG. 4 shows a method of manufacturing the electron source substrate in this embodiment. Hereinafter, a basic configuration and a manufacturing method of the image forming apparatus according to the present embodiment will be described with reference to FIGS. 1, 2, and 4. FIG. FIG. 4 shows one electron-emitting device 11 for simplicity.
Only and the vicinity thereof are shown in an enlarged manner.
This is an example of a manufacturing process of an electron source substrate 61 in which a large number of electron-emitting devices 11 are arranged in a simple matrix.

Step-a A 1.0 μm thick SiO ₂ film is formed as a sodium diffusion control layer 9 on a cleaned blue glass substrate 1 by a sputtering method.

Step-b Next, on the substrate 1 on which the sodium diffusion control layer 9 is formed,
5 nm thick Ti and 50 nm Ru are deposited by sputtering. Thereafter, the patterns of the electrodes 2 and 3 are formed of photoresist, the laminated film in which Ru is formed on Ti other than the patterns of the electrodes 2 and 3 by dry etching is removed, and finally the photoresist pattern is removed. , Electrodes 2 and 3 are formed.

Step-c On the substrate 1 on which the sodium diffusion control layer 9 and the electrodes 2 and 3 are formed, a pattern of the wiring 6 is formed by screen printing using an Ag paste, dried, and baked at 500 ° C. , Ag of a desired shape is formed.

Step-d 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 using a glass paste, drying and baking are repeated again to form an interlayer insulating layer 8 of a desired shape made of glass.

Step-e 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 fired at 500 ° C. Then, an upper wiring 7 of a desired shape made of Ag is formed.

By the above steps, the electrodes 2 and 3 are connected to the wiring 6 and
7, a substrate connected in a matrix can be formed.

Here, along the line indicated by AA ′ in FIG. 2, the electron probe microanalysis (EPM) is performed.
FIG. 8 shows an example of the result of measuring the distribution of Ag elements in the electron source substrate 61 according to the present invention by taking the distance (μm) from the wiring 6 on the horizontal axis by the method A). For comparison, an example of the result of measuring the distribution of the same Ag element when the electrodes 2 and 3 made of Pt having a higher standard monopolar potential than Ag and the wirings 6 and 7 made of Ag are formed is shown below. FIG.
Shown in As can be seen from FIGS. 8 and 9, it is understood that the diffusion of Ag from the wirings 6 and 7 to the electrodes 2 and 3 is suppressed by the present invention.

Step-f Next, a conductive thin film 4 is formed so as to span the gap between the 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. The conductive thin film 4 thus obtained contained PdO as a main component and had a thickness of about 10 nm.

Through the above steps, the sodium diffusion control layer 9, the lower wiring 6, the interlayer insulating layer 8, the upper wiring 7, the electrodes 2, 3 and the conductive thin film 4 are formed on the base 1, and the electron source substrate 61
Was prepared.

Hereinafter, an example in which an image forming apparatus is configured using the electron source substrate according to the present embodiment will be described with reference to FIGS.

The electron source substrate 61 manufactured as described above
Is fixed on the rear plate 62, and a face plate 67 (glass substrate 64) is placed 5 mm above the electron source substrate 61.
Is formed with a fluorescent film 65 and a metal back 66 formed on the inner surface of the support plate 63 via a support frame 63, and frit glass is applied to a joint between the face plate 67, the support frame 63, and the rear plate 62. At 400 ° C in air
The joint was fixed by baking for 0 minutes. The fixing of the electron source substrate 61 to the rear plate 62 was also performed using frit glass.

The fluorescent film 65 is composed of only the fluorescent material 72 in the case of monochrome, but in this embodiment, the fluorescent material 72 adopts a stripe shape, a black stripe of the black conductor 71 is formed first, and the gap portion is formed. Apply each color phosphor to
The fluorescent film 65 was produced. As a 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. After the fluorescent film 65 is formed, the metal back 66 performs a smoothing process (usually called filming) on the inner surface of the fluorescent film 65, and then forms an Al film.
Was produced by vacuum evaporation. Face plate 67
In order to further increase the conductivity of the fluorescent film 65,
In some cases, a transparent electrode (not shown) is provided on the outer surface side of 5, but in this embodiment, it was omitted because only the metal back 66 provided sufficient conductivity. At the time of performing the above-described sealing, in the case of color, the phosphors of each color and the electron-emitting device 11 must correspond to each other, so that 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 external terminals A voltage is applied between the electrodes 2 and 3 through the terminals Doy1 to Doyn, and the conductive thin film 4
Was formed. The voltage waveform of the forming process is the same as that shown in FIG. In this embodiment, the pulse width T1 of the voltage waveform is 1 msec and the pulse interval T2
Was set to 10 msec, and forming was performed in a vacuum atmosphere of about 1.3 × 10 ⁻³ Pa.

Next, when the pressure in the panel-shaped glass container is 1.
After evacuation was continued until the pressure reached 3 × 10 ⁻⁶ Pa, the total pressure was 1.3 × 10 ⁻⁴ Pa from the exhaust pipe of the panel-shaped glass container.
An organic substance was introduced into and maintained in the panel-shaped glass container such that External terminals Dox1 to Doxm;
Electrodes 2 through external terminals Doy1 to Doyn
During the period 3, a pulse voltage having a peak value of 15 V was applied to perform an activation process.

As described above, the forming process and the activating process were performed to form the electron-emitting portions 5 of the respective electron-emitting devices 11.

Next, the gas was evacuated to a pressure of about 1.3 × 10 ⁻⁴ Pa, and an exhaust pipe (not shown) was welded by heating with a gas burner, and the glass container was sealed as a vacuum envelope 69. . Finally, gettering was performed by a high-frequency heating method in order to maintain the pressure after sealing.

In the image forming apparatus according to the present embodiment completed as described above, each of the electron-emitting devices 11 has an outer container terminal Dox1 to Doxm and an outer container terminal Doy1.
Through Doyn, by applying a scanning signal and a modulation signal from signal generation means (not shown), respectively.
Electrons are emitted and the metal back 6
6, or a high voltage of 5 kV or more is applied to a transparent electrode (not shown) to accelerate the electron beam and collide it with the fluorescent film 65;
An image was displayed by excitation and light emission.

The image forming apparatus according to the present embodiment 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 configuration of an electron source substrate 61 according to this embodiment is the same as that of Embodiment 1.

Step-a A 1.0 μm-thick phosphorus-doped silica glass (PSG) film is formed as a sodium diffusion control layer 9 on the cleaned blue glass substrate 1 by a CVD method.

Step-b Next, on the substrate 1 on which the sodium diffusion control layer 9 was formed,
Ti having a thickness of 5 nm is deposited by sputtering, followed by Rh having a thickness of 50 nm. Thereafter, the patterns of the electrodes 2 and 3 are formed of photoresist, the laminated film in which Rh is formed on Ti other than the patterns of the electrodes 2 and 3 is removed by dry etching, and finally the photoresist pattern is removed. , Electrodes 2 and 3 are formed.

Step-c On the substrate 1 on which the sodium diffusion control layer 9 and the electrodes 2 and 3 are formed, a pattern of the wiring 6 is formed using an Ag paste by screen printing, dried, and fired at 500 ° C. Then, a wiring 6 having a desired shape made of Ag is formed.

Step-d 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 using a glass paste, drying and baking are repeated again to form an interlayer insulating layer 8 of a desired shape made of glass.

Step-e 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.

By the above steps, the electrodes 2 and 3 are connected to the wiring 6 and
7, the electron source substrates 61 connected in a matrix were formed.

Here, along the line AA ′ in FIG.
Electron probe microanalysis (EPMA)
The distribution of Ag element was measured by the method of FIG.
The results similar to those shown in FIG. 4 are obtained, and it is understood that the diffusion of Ag from the wirings 6 and 7 to the electrodes 2 and 3 is suppressed by the present embodiment.

Step-f Next, a conductive thin film 4 is formed so as to span the gap between the 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. The conductive thin film 4 thus obtained contained PdO as a main component and had a thickness of about 10 nm.

Through the above steps, the sodium diffusion control layer 9, the lower wiring 6, the interlayer insulating layer 8, the upper wiring 7, the electrodes 2, 3 and the conductive thin film 4 are formed on the base 1, and the electron source substrate 61 is manufactured. did.

After that, similarly to the first embodiment, when the image forming apparatus is configured by using the electron source substrate 61 according to the present embodiment, the image forming apparatus according to the present embodiment also has a luminance (which can be sufficiently satisfied as a television). At about 150 fL), a good image could be stably displayed for a long time.

[0099]

As described above, according to the present invention,
As a material of the electrode material, at least a part of the constituent elements is composed of a noble metal element, and, compared to the element constituting the wiring, by using a material having a standard single-pole potential lower than that of the noble metal element, the wiring metal is formed in the electrode Since diffusion is difficult, diffusion of wiring metal which causes deterioration of electron emission characteristics can be suppressed, and as a result, an electron source substrate having good characteristics can be obtained. Furthermore, using it, a large screen flat type image forming apparatus capable of holding a good image for a long time, for example,
A color flat TV can be realized.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a schematic configuration of an electron source substrate according to an embodiment of the present invention.

FIG. 2 is a bird's-eye view of an electron-emitting device of an electron source substrate according to an embodiment of the present invention and the vicinity thereof;

FIG. 3 is a cross-sectional view of an electron-emitting device of an electron source substrate according to an embodiment of the present invention and its vicinity.

FIG. 4 is a perspective view for explaining a basic method of manufacturing the electron source substrate according to the embodiment of 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 perspective view illustrating a basic configuration of an image forming apparatus according to the present invention.

FIG. 7 is a plan view illustrating an example of a fluorescent film used in the image forming apparatus of FIG. 6;

FIG. 8 is a diagram for explaining an effect of the present invention in the example.

FIG. 9 is a comparative diagram for explaining the effect of the present invention in an example.

FIG. 10 is a plan view showing a configuration of a conventional electron source substrate.

FIG. 11 is a bird's-eye view showing a configuration of a conventional electron source substrate.

[Explanation of symbols]

1: Base, 2, 3: electrode, 4: conductive thin film, 5: electron emitting portion, 6, 7: wiring, 8: interlayer insulating layer, 9: sodium diffusion control layer, 11: electron emitting element, 61: electron Source board,
62: rear plate, 63: support frame, 64: glass substrate, 65: fluorescent film, 66: metal back, 67: face plate, 68: high voltage terminal, 69: vacuum envelope, 7
1: black conductor, 72: phosphor.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshitaka Arai 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (Reference) 5C031 DD17 DD19 5C036 EE08 EE14 EF01 EF06 EF09 EG12 EH08

Claims (18)

[Claims] 1. An electron source substrate comprising: an electron-emitting device having a pair of electrodes on a substrate; and a wiring connected to the electrodes, wherein the electrodes are configured such that at least a part of constituent elements is a noble metal element. An electron source substrate, wherein the standard monopolar potential of the noble metal element is lower than that of the element constituting the wiring. 2. The wiring according to claim 1, wherein the wiring is made of any one of Ag, Cu, and Au, and an alloy containing any one of these metals.
3. The electron source substrate according to claim 1. 3. The electron source substrate according to claim 1, wherein at least a part of constituent elements of the wiring is Ag. 4. The electrode according to claim 1, wherein the electrode is made of at least one element selected from the group consisting of Ru, Rh, and Os at a portion in contact with the wiring. Electron source substrate. 5. An electron source substrate comprising: an electron-emitting device having a pair of electrodes on a substrate; and a wiring connected to the electrodes, wherein the wiring is any one of Ag, Cu, and Au. Metal,
Alternatively, the electron source substrate includes an alloy including any one of the metals, and the electrode includes at least one element selected from Ru, Rh, and Os. 6. The electron source substrate according to claim 1, wherein a main component of the base is made of silica at a portion in contact with at least one of the electrode and the wiring. 7. The electron source substrate according to claim 1, wherein said electron-emitting device further includes a conductive film having an electron-emitting portion in a part thereof. 8. The electron source substrate according to claim 7, wherein the conductive film is made of one of Pd, PdO, and a mixture thereof. 9. The electron source substrate according to claim 1, wherein said electron-emitting device is a surface conduction electron-emitting device. 10. A plurality of said electron-emitting devices are arranged,
The electron source substrate according to claim 1, wherein electrons are emitted in response to an input signal. 11. A plurality of said electron-emitting devices are arranged in parallel, a plurality of rows of electron-emitting devices having both ends of each electron-emitting device connected to said wiring, and a modulation signal is applied to said electron-emitting device. The electron source substrate according to claim 10, further comprising a modulating unit that performs the modulation. 12. A pair of electrodes of the electron-emitting device are connected to m X-directional wires and n Y-directional wires electrically insulated from each other, and the electron-emitting devices are arranged in a matrix. The electron source substrate according to claim 10, wherein: 13. The electron source substrate according to claim 1, wherein said base is made of non-alkali glass. 14. The device according to claim 1, wherein a sodium diffusion control layer is formed on the surface of the base, and the electron-emitting device and the wiring are arranged on the sodium diffusion control layer.
3. The electron source substrate according to any one of 2. 15. The method of manufacturing an electron source substrate according to claim 1, wherein the wiring is formed by printing a metal paste and heating and baking. Manufacturing method. 16. A method comprising the steps of: activating an electron-emitting device in an atmosphere containing a carbon compound; and discharging a residue of the carbon compound introduced during the activation. The method for manufacturing an electron source substrate according to claim 15, wherein 17. An apparatus for forming an image based on an input signal, comprising at least an image forming member and an image forming member.
5. An image forming apparatus comprising the electron source substrate according to any one of 4. 18. An image forming apparatus in which an electron source substrate and a substrate having an image forming member are arranged to face each other, wherein the electron source substrate is any one of claims 1 to 14. An image forming apparatus, which is a substrate.