Manufacture of electron emission element, electron source and image forming device

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a method for manufacturing an electron emitting element, an electron source, a display element, and an image forming apparatus, and more particularly to the manufacturing method using an inkjet method.

【0002】

[Conventional technology]

Conventionally, there are roughly two types of electron emitting elements, a thermoelectron emitting element and a cold cathode electron emitting element. The cold cathode electron emitting element includes a field emission type (hereinafter referred to as "FE type"), a metal / insulating layer / metal type (hereinafter referred to as "MIM type"), and a surface conduction type electron emitting element.

【0003】

Examples of FE type electron emitting elements are WPDyke & W.W.Dolan, Field emission, Advance in Electron Physics, 8,89 (1956) or CASpindt, PHYSICAL Properties of thin-film field emission cathodes with molybdenumcones, J. Those disclosed in .Appl.Phys., 47,5248 (1976), etc. are known.

【0004】

As an example of the MIM type electron emitting device, those disclosed in CAMead, Operation of Tunnel-Emission Devices, J. Apply.Phys., 32,646 (1961)] and the like are known.

【0005】

The surface-conduction electron emitting element utilizes a phenomenon in which electrons are emitted by passing an electric current through a thin film having a small area formed on a substrate in parallel with the film surface. An example of this surface-conduction electron emitting element is SnO.₂ Thin film [MIElinson, Radio Eng. Electron Pys., 10,1290 (1965)], Au thin film [G.Dittmer: ThinSolid Films, 9,317 (1972)], In₂ O₃ / SnO₂Using a thin film [M. Hartwell and CGFonstad, IEEE Trans.ED Conf., 519 (1975)] and using a carbon thin film [Hisashi Araki et al .: Vacuum, Vol. 26, No. 1, 22 pages (1983)] etc. have been reported.

【0006】

As a typical example of these surface-conduction electron emitting devices, the device configuration of the above-mentioned M. Hartwell is schematically shown in FIG. In the figure, 1 is a substrate made of an insulating substrate or the like. Reference numeral 4 denotes a conductive film, which is composed of a metal oxide thin film or the like formed by sputtering in an H-shaped pattern, and an electron emitting portion 5 is formed by an energization process called energization forming described later. The element electrode spacing L in the figure is set to 0.5 mm to 1 mm, and W'is set to 0.1 mm.

【0007】

In addition to the above examples, the applicant has reported a surface-conduction electron-emitting device having a pair of element electrodes and a conductive film bonded to the element electrodes and formed separately from the element electrodes on a substrate. Has been done. The structure is described in, for example, Japanese Patent Application Laid-Open No. 7-235255. FIG. 19 schematically shows the configuration. It has been reported that the conductive film 4 is preferably made of conductive fine particles in order to form a preferable electron emitting portion 5, and for example, a fine particle film of palladium oxide PdO is preferably used.

【0008】

Conventionally, in these surface-conduction electron emitting elements, it has been common to form an electron emitting portion 5 on a conductive film 4 by an energizing treatment called energizing forming in advance before emitting electrons. That is, energization forming means that a DC voltage, a very slow rising voltage (for example, about 1 V / min) or a pulse voltage is applied to both ends of the conductive film 4 to energize and locally destroy, deform or alter the conductive film. At the very least, it is to form the electron emitting part 5 which is in a state of high electrical resistance. In the electron emitting section 5, a crack is generated in a part of the conductive film 4, and electrons are emitted from the vicinity of the crack. The surface-conduction electron emitting element subjected to the energization forming treatment applies a voltage to the conductive film 4 and causes an electric current to flow through the element to emit electrons from the electron emitting unit 5 described above.

【0009】

However, according to this method, it is difficult to sufficiently control in which part of the conductive film and in what shape the electron emitting portion is formed, and when a large number of elements are produced, electron emission is performed. The position where the part is formed varies from element to element, and it may not be possible to do the same, or the electron emitting part may meander between both electrodes. Such variations in the position and shape of the electron emission section are also reflected in the electron emission characteristics of the element, and the emission current Ie and the electron emission efficiency η (the ratio of the emission current Ie to the current If flowing through the element, that is, η = Ie / If) may be different for each element.

【0010】

When a large number of electron emitting elements are arranged on a substrate and used, for example, when an image forming apparatus is configured by this, even if a video signal is input so as to have uniform brightness, the emission current is emitted for each electron emitting element. The Ie will be different, which causes uneven brightness of the image, which is a serious problem.

【0011】

Further, as the meandering width of the electron emitting portion increases, the diameter of the electron beam increases accordingly, and the size of the bright spot on the fluorescence film of the image forming apparatus also increases. Therefore, when the pixel pitch is narrowed in order to display a high-definition image, a part of the electron beam is irradiated to the adjacent pixels, and there is a concern that the quality of the image is deteriorated.

【0012】

In order to avoid such inconvenience, the applicant has proposed several methods. For example, in Japanese Patent Application Laid-Open No. 1-112633, the conductive film is formed of two types of conductors having different melting points, and an electron emitting portion is formed along a line in which the two types of conductors are in contact with each other. An example of controlling the position of the electron emitting part is described. In Japanese Patent Application Laid-Open No. 2-247940, a step forming member is provided so that a step is formed at a position where an electron emitting portion is to be formed, a conductive film is formed across the step forming member, and the above is performed by energization forming treatment. A method of forming an electron emitting portion along a step is described. Further, Japanese Patent Application Laid-Open No. 8-96699 describes a method in which the thickness of one element electrode is increased and an electron emitting portion is formed along the edge of the element electrode. Further, in the application of Japanese Patent Application No. 7-325279, the composition of a part of the conductive film is changed by a method such as locally irradiating a laser beam or the like to form a part having a large resistance value. A method of forming an electron emitting portion in this portion by energization forming is described.

【0013】

As described above, in the step of forming the electron emitting portion by the energization forming process, several methods have been devised to control the position and shape of the electron emitting portion to some extent. However, in the above method, a laser beam is used or a member such as a protrusion is formed in order to make the shape, composition, etc. of the conductive film at the position where the electron emitting portion should be formed different from that of other conductive films. For example, the technique of microfabrication is used, or the steep shape of the edge of the element electrode formed by the same technique of microfabrication is used.

【0014】

[Problems to be Solved by the Invention]

The present invention has been made in view of the above-mentioned problems in the conventional example, and an object of the present invention is a method for manufacturing an electron emitting element having a simple process and low cost, and a method for manufacturing an electron source and an image forming apparatus using the same. Is to provide. Another object of the present invention is to provide an electron emitting element having excellent mass productivity and an improved yield, an electron source using the electron emitting element, and a method for manufacturing an image forming apparatus. Another object of the present invention is to provide an electron emitting element having improved uniformity of electron emitting characteristics, an electron source using the electron emitting element, and a method for manufacturing an image forming apparatus. Another object of the present invention is to provide an electron emitting element capable of controlling the formation position of an electron emitting portion, an electron source using the electron emitting element, and a method for manufacturing an image forming apparatus.

【0015】

[Means for solving problems]

In order to solve the above problems, in the present invention, a pair of opposing element electrodes formed on the substrate, a conductive film connected to both of the element electrodes, and a part of the conductive film are formed. In the method for manufacturing an electron emitting element having an electron emitting portion, the manufacturing method (1) applies an ink containing a substance as a raw material of a material forming the conductive film to a predetermined position as droplets by an inkjet device. (2) The applied droplets are dried and / or fired to form a conductive film, and (3) a voltage is applied between the pair of element electrodes to form the conductive film. It has a step of forming an electron emitting part by passing an electric current, and the conductive film formed by the above steps (1) and (2) has an electron emitting part due to the generation of Joule heat by the step (3). It is characterized in that steps (1) and (2) are performed so as to have a latent image in which is easily formed.

【0016】

As the inkjet device, a so-called bubble jet type inkjet device that discharges the liquid by applying heat to the liquid can be used.

【0017】

The method for manufacturing an electron source of the present invention includes a pair of opposing element electrodes, a conductive film connected to both of the element electrodes, and an electron emission portion formed in a part of the conductive film. A method for manufacturing an electron source having a plurality of elements arranged on a substrate and having wirings connected to these electron emitting elements is characterized in that the electron emitting element is manufactured by the method described above. ..

【0018】

Further, in the method for manufacturing an image forming apparatus of the present invention, a pair of opposing element electrodes, a conductive film connected to both of the element electrodes, and an electron emitting portion formed in a part of the conductive film are formed. An image is produced by arranging a plurality of electron emitting elements having the same on a substrate and emitting light by irradiating an electron source having a wiring connected to these electron emitting elements and electrons emitted from the electron source. A method of manufacturing an image forming apparatus in which an image forming member to be displayed is enclosed in a vacuum vessel is characterized in that the electron source is manufactured by the method described above.

【0019】

[Action]

The present invention attempts to control the formation position of the electron emitting portion by utilizing the merits described later of the inkjet method. That is, when manufacturing a product using an electron emitting element, it is natural that it is preferable for cost reduction and the like to be able to manufacture the product without using a technique such as microfabrication. For example, as a method of forming a conductive film, instead of a method of patterning by a microfabrication technique such as photolithography after forming a film, a solution containing a precursor of the material of the conductive film is applied to a substrate by an inkjet device. A method of drying, heat-treating, etc. after the application is conceivable. At this time, if microfabrication is used to control the position of the electron emitting part as in the above-mentioned method, it should be manufactured using an inkjet device. The advantage of is lost. Further, the element electrode and the wiring can be formed by printing or by using an inkjet device similar to the above, but the edge of the electrode formed by this is the same as when the metal thin film is microfabricated. It is difficult to form a steep shape, and it is difficult to apply a method that utilizes the effect of steep edges.

【0020】

As described above, the conventionally devised method of controlling the position of the electron emitting unit is not always suitable for use in combination with the method of manufacturing an electron emitting element using an inkjet device.

【0021】

Therefore, there has been a demand for a method for controlling the position of an electron emitting part, which is suitable for use in combination with a method for manufacturing a conductive film, an electrode, and a wiring by an inkjet device, printing, or the like.

【0022】

In the method of manufacturing an electron emitting element using an inkjet device, when a large number of electron emitting elements are arranged and used on a large-area substrate, the process and the manufacturing device are different from the method of patterning using a photolithography technique or the like. It is simpler and its merits are extremely large, and from this point of view, the above requirements are strong.

【0023】

The present invention has been made based on the above findings, and in the present invention, when a conductive film is formed by applying a raw material as droplets using an inkjet device, an electron emitting unit is subjected to the above-mentioned field forming treatment. It forms a "latent image" in which is easily formed, and controls the position where the electron emitting portion is formed.

【0024】

The droplets applied onto the substrate usually form a substantially circular conductive film. This circular conductive film or a film such as a metal compound that is a precursor thereof is hereinafter referred to as "dot". One dot may be formed by applying one droplet, or may be formed by repeatedly applying a plurality of droplets to the same place.

【0025】

FIGS. 22A and 22B schematically show the configuration of the head 91 of the inkjet device. The figure shows the configuration of a bubble jet (BJ) head among inkjet devices. FIG. 22A shows a single droplet ejection port 94, and FIG. 22B shows a plurality of ejection ports arranged in parallel. Is.

【0026】

The heater 92 heats the raw material solution of the conductive film in the solution flow path 93 to generate bubbles instantaneously, so that the solution is made into droplets of about several ng to several tens of ng from the discharge port 94 in a predetermined amount. Is discharged. Instead of this, a piezo jet method may be used in which the solution is discharged by utilizing the deformation of the piezo element due to the piezoelectric effect.

【0027】

Reference numeral 95 denotes a solution supply pipe, which is connected to a solution tank (not shown) to continuously supply the solution into the head 91.

【0028】

Specifically, some methods as described below are proposed. First, in order to form a conductive film, when a plurality of dots are applied in the direction connecting a pair of element electrodes, a relatively thick portion and a relatively thin portion are formed, and the film thickness is formed. This is a method of using a relatively thin portion of the above as a latent image for forming an electron emitting portion.

【0029】

This latent image portion may be located at one of the element electrodes as shown in FIGS. 1 and 2, or may be located at the center of the element electrode gap as shown in FIG.

【0030】

As a method of forming a relatively thin portion and a relatively thick portion, a method of controlling the number of times the droplets are overlapped when the droplets are formed in the same place by an inkjet device, or a method of controlling the concentration. A method of applying different droplets to each position can be adopted.

【0031】

In this case, the ratio of the film thickness of the dots forming the thick portion to the film thickness of the dots forming the thin portion is preferably 2 or more.

【0032】

In addition, as described above, when droplets are applied in layers at the same position in order to adjust the film thickness of the dots, or dots having the same properties such as 4-1 dots in Fig. 2A or 4-2 dots are used. When forming the droplets, droplets may be continuously applied, but when forming dots having different properties, for example, after applying the droplets for forming the dots 4-1 in FIG. 1A, this is applied. It is necessary to add droplets for forming 4-2 dots after drying or further heating and firing. This is because if droplets of dots with different properties are partially overlapped with the previous droplets before the previously applied droplets are dried, the two will be mixed in the state of a solution, which is the purpose. This is because the formation of the latent image to be performed may not be achieved. This also applies to the other methods described below.

【0033】

The second is to utilize the difference in current density (during the forming process) caused by the shape of the dots. That is, as shown in FIG. 4, the center of the dot is formed not near the center of the element electrode gap but toward one element electrode, and the conductive film is wide at the edge of one element electrode and the other element. It should be narrow at the electrode edge. In this way, in the vicinity of the electrode edge having the narrower width, the current density becomes the highest during the forming process, and the electron emitting portion is likely to be formed. The distribution of the film thickness of the conductive film cannot be unequivocally determined because it changes depending on the conditions, but if appropriate conditions are selected, the thickness can be made thicker in the central portion of the dot and thinner in the peripheral portion. In this case, the effect of the position control of the electron emitting portion by the above method can be further ensured.

【0034】

In order to ensure that the electron emitting part is formed on one element electrode, the width of the conductive film at both element electrode edges is (w).₁ / w₂ ) 2 (W₁ , W₂ It was found by preliminary examination that each of the above should satisfy the relationship (width of the conductive film at the edge portion of the element electrodes 2 and 3).

【0035】

When a plurality of dots are partially overlapped in the direction perpendicular to the direction connecting the pair of element electrodes, the width of the conductive film as a whole is not so different at both edges, but the dots. Since the film thickness of the conductive film differs due to the difference in the way of overlapping, the same effect occurs.

【0036】

The third method is a method in which a part of the conductive film has a higher resistivity than the other parts, and a part having a relatively high resistivity is used as a latent image.

【0037】

For this purpose, a method of applying a metal that is hard to be oxidized and a raw material for forming a metal that is easily oxidized as droplets to form a metal and a metal oxide portion, respectively, even if the raw materials of the same metal are heat. A method in which raw materials having different decomposition temperatures are applied as droplets, the thermal decomposition process is appropriately adjusted to form metal and its oxide parts, respectively, a reducing agent is partially placed, and a part of the conductive film is formed. A method in which a portion without a reducing agent is used as a metal oxide, or two types of droplets forming different types of metal films are added to a metal to form dots, and an alloy is formed at the overlapping portion of both dots. (For example, a film of Ni and Cr is formed, and the alloyed part becomes a dichrome alloy and has a high resistance. ) Etc. can be used.

【0038】

In the above, Pd and Pt can be exemplified as a combination of a metal that is difficult to oxidize and a metal that is easily oxidized.

【0039】

In addition, raw materials containing the same metal but having different thermal decomposition temperatures include, for example, metal compounds having a relatively low thermal decomposition temperature, palladium acetate-bis (N-butylethanolamine), palladium acetate-di (N-butylethanolamine), and the like. Select one of palladium-bis acetate (N, N-diethylethanolamine) and palladium-bis acetate (N, N-dimethylethanolamine) to select a metal compound with a relatively high thermal decomposition temperature. Any one of amine, palladium acetate-monobutanolamine, and palladium acetate-monopropanolamine may be selected.

【0040】

As the reducing substance, carbon fine particles, platinum carbon fine particles, and the like can be used. These reducing substances can be arranged by applying a dispersion liquid of fine particles of the reducing substance to a predetermined position as droplets by an inkjet device.

【0041】

In the following, the part where the electron emission part is easily formed by the energization forming process by reducing the film thickness or width of the conductive film is called "structural latent image", and the part where the resistivity is increased is also increased. The part where is easily formed is called a "composition latent image".

【0042】

It is conceivable to form a latent image similar to the latent image by the above method by patterning by a conventional microfabrication technique, but in comparison with this, the method of the present invention using an inkjet device is a process or a manufacturing device. In addition to being simple, it also has the following advantages.

【0043】

That is, according to the present invention, as shown in the first and third methods described above, a method of forming a conductive film by varying the thickness of dots or by applying droplets of different materials is used. When it is realized by patterning by fine processing, a conductive film or a part of the film of the raw material thereof is once formed and patterned, and then a lift-off mask is formed on the conductive film or a mask for lift-off is formed on the film. It is necessary to etch in order to pattern the film, but in order to do this, only the film formed on top of the initial film and the adhesion strength between the initial film and the substrate must be strong to some extent. Conditions such as selective etching must be satisfied. For this reason, there are restrictions on the materials that can be applied. On the other hand, in the present invention using the inkjet device, since patterning by microfabrication is not performed, there are no restrictions due to the above-mentioned conditions, and the degree of freedom in material selection is large. That is, it is a manufacturing method applicable to various combinations of conductive film materials.

【0044】

Subsequently, an example of an electron emitting device to which the manufacturing method of the present invention can be applied will be described with reference to FIGS. 1 to 6. FIG. 1 is a schematic plan view and a cross-sectional view showing the configuration of a surface-conduction electron emitting element to which the present invention can be applied. In FIG. 1, 1 is a substrate, 2 and 3 are element electrodes, 4 is a conductive film, and 5 is an electron emitting part.

【0045】

As the substrate 1, SiO formed on quartz glass, glass having a reduced impurity content such as Na, blue plate glass, and blue plate glass by a sputtering method or the like.₂ Ceramics such as alumina, Si substrate and the like can be used.

【0046】

As the material of the element electrodes 2 and 3 facing each other, a general conductor material can be used. This is, for example, a metal or alloy such as Ni, Cr, Au, Mo, W, Pt, Ti, Al, Cu, Pd or Pd, Ag, Au, RuO.₂, Pd-Ag and other metals or printed conductors composed of metal oxides and glass, In₂O₃ -SnO₂It can be appropriately selected from transparent conductors such as, and semiconductor materials such as polysilicon.

【0047】

The element electrode spacing L, the element electrode length W, and the like are designed in consideration of the applied form and the like. The element electrode spacing L can preferably be in the range of several hundred nm to several hundred μm, and more preferably in the range of several μm to several tens of μm.

【0048】

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

【0049】

In addition to the configuration shown in FIG. 1, a configuration in which the conductive film 4 and the opposing element electrodes 2 and 3 are laminated in this order on the substrate 1 is also possible.

【0050】

For the conductive film 4, it is preferable to use a fine particle film composed of fine particles in order to obtain good electron emission characteristics. The film thickness is appropriately set in consideration of step coverage to the element electrodes 2 and 3, the resistance value between the element electrodes 2 and 3, the energization forming condition described later, and the like, but is usually from several hundred pm to several hundred nm. The range is preferably in the range of 50 nm rather than 1 nm. When a structural latent image is formed by utilizing the difference in film thickness as described above, the film thickness of that portion needs to be thinner than that of other portions, and may be thinner than the above range. The resistance value of the conductive film is R_S Is 10² From 10⁷ It is the value of Ω / . R_S Is the resistance R of a thin film with a thickness of t, a width of w and a length of l, R = R_S The amount that appears when expressed as (l / w), and if the resistivity of the film is a constant value ρ regardless of location, then R_S It can be expressed as = ρ / t.

【0051】

In addition, in the method other than the method described as the second specific example of the present invention, the R of the latent image portion is used._S Must be larger than the others (which may be the case in the second embodiment above), and the R in this part_S The value of may be greater than or equal to the above upper limit.

【0052】

The materials constituting the conductive film 4 are metals such as Pd, Pt, Ru, Ag, Au, Ti, In, Cu, Cr, Fe, Zn, Sn, Ta, W, Pb, PdO, SnO.₂ , In₂ O₃ , PbO, Sb₂ O₃ Etc. are appropriately selected from metal oxides and the like.

【0053】

The fine particle film described here is a film in which a plurality of fine particles are aggregated, and the fine structure thereof is a state in which the fine particles are individually dispersed or arranged, or a state in which the fine particles are adjacent to each other or overlap each other (some fine particles are aggregated, and the fine particles are assembled. (Including the case where an island-like structure is formed as a whole). The particle size of the fine particles is in the range of several hundred pm to several hundred nm, preferably in the range of 1 nm to 20 nm.

【0054】

Since the term "fine particles" is frequently used in the present specification, its meaning will be described. Small particles are called "fine particles", and smaller particles are called "ultrafine particles". It is widely practiced to refer to "clusters" that are smaller than "ultrafine particles" and have a number of atoms of several hundred or less. However, each boundary is not strict and changes depending on what kind of property is focused on when classifying. Further, "fine particles" and "ultrafine particles" may be collectively referred to as "fine particles", and the description in this specification is in line with this.

【0055】

"Experimental Physics Course 14 Surfaces and Fine Particles" (edited by Koreo Kinoshita, published by Kyoritsu Shuppan, September 1, 1986) states as follows. "In this paper, when we say fine particles, the diameter is about 2 to 3 μm to 10 nm, and when we say ultrafine particles, we mean the particle size is about 10 nm to 2 to 3 nm. It is not a strict one because it is simply written as fine particles, but it is a rough guide. When the number of atoms that make up a particle is about 2 to several tens to several hundreds, it is called a cluster "(page 195). Lines 22-26).

【0056】

In addition, the definition of "ultrafine particles" in the "Hayashi / Ultrafine Particles Project" of the New Technology Development Corporation had a smaller lower limit of particle size, as follows.

【0057】

"In the" Ultra Fine Particle Project "(1981-1986) of the Creative Science and Technology Promotion System, particles with a particle size (diameter) in the range of about 1 to 100 nm are called" ultra fine particles ". Then one ultrafine particle is about 100 ~ 10⁸ It is an aggregate of about 10 atoms. On an atomic scale, ultrafine particles are large to large particles. ("Ultrafine Particles-Creative Science and Technology-" Hayashi Main Tax, Ryoji Ueda, Akira Tasaki ed .; Mita Publishing 1988, page 2, lines 1 to 4) "Even smaller than ultrafine particles, that is, several to several hundred atoms A single particle composed of is usually called a cluster "(ibid., P. 2, lines 12-13).

【0058】

Based on the above general term, "fine particles" in the present specification are aggregates of a large number of atoms and molecules, and the lower limit of the particle size is about several hundred pm to 1 nm and the upper limit is about several μm. I will refer to things.

【0059】

The electron emitting portion 5 is composed of high-resistance cracks formed in a part of the conductive film 4, and depends on the film thickness, film quality, material of the conductive film 4, the energization forming described later, and the like. Conductive fine particles having a particle size in the range of several hundred pm to several tens of nm may depend on the inside of the electron emitting unit 5. The conductive fine particles contain some or all of the elements of the material constituting the conductive film 4. The electron emitting portion 5 and the conductive film 4 in the vicinity thereof may have carbon and carbon compounds. Next, the manufacturing method of the present invention will be specifically described with reference to schematic views (FIGS. 1 to 6) and process explanatory views (FIGS. 20A to 21G) showing an example of the configuration of the electron emitting device.

【0060】

1) After thoroughly cleaning the substrate 1 with detergent, pure water, an organic solvent, etc. (Fig. 20A), element electrodes 2 and 3 are formed (Fig. 20B). As a method for forming the element electrode, a method in which a paste of a conductor material is formed into a desired shape by a printing method and then heat-treated, or a solution such as a metal compound is formed on a substrate so as to have a desired shape by an inkjet method. After being applied to the electrode, the element electrode material is deposited by a method of forming an electrode by changing to a conductive material by heat treatment, a vacuum vapor deposition, a sputtering method, etc., and then an electrode having a predetermined shape is formed by using, for example, photolithography technology. Any method may be used, and the method is appropriately selected according to the purpose of use and the like.

【0061】

2) Subsequently, a substance that is a raw material of the conductive film is applied onto the substrate as droplets by a droplet applying device such as an inkjet device (hereinafter, the material of the droplets is referred to as "ink for forming a conductive film"). .. The ink for forming a conductive film may be in any state as long as it can be applied to a substrate in a desired shape by using a droplet applying device, but fine particles of a conductive material such as the above-mentioned metal are dispersed in water or a solvent. A liquid or a solution of a metal compound (solvent is water, organic solvent, etc.) is used.

【0062】

When the conductive film is made of the above metal, alloy or metal compound, the appropriate range of the metal content of the conductive film forming ink varies depending on the type of metal element, the type of metal compound, etc., but is 0.01 to 5 wt. The% range is desirable. If the content is too low, a large amount of droplets must be applied in order to form a conductive film having a desired thickness, which not only increases the time required for this step but also forms a desired shape. It becomes difficult to do. On the contrary, if the content is too large, the film thickness of the resulting conductive film may become significantly non-uniform, and it becomes difficult to control the electron emission characteristics.

【0063】

First, the method of forming a structural latent image will be described. Figure 1 shows an example in which dots of two types of conductive films with different film thicknesses are formed so that some of them overlap. As a method of making the film thickness different, inks for forming a conductive film having different metal contents are used, and inks having a high metal content are used for thick dots and inks having a low metal content are used for dots having a thin film thickness. There is a method of forming by differently, and a method of forming by making the number of times of applying the droplets different.

【0064】

20C to 21E show an example of the above steps, in which a droplet 96-1 of ink having a high metal content is ejected from the ejection port 94 of the inkjet device and connected to one of the element electrodes 2. (Fig. 20C). Subsequently, this is heated and fired to form dots 4-1 of a thick conductive film (Fig. 20D).

【0065】

Next, droplets 96-2 of ink having a low metal content are applied so as to be connected to the other element electrode 3 (FIG. 21E), and heat-baked to form dots 4-2 of a thin conductive film. (Fig. 21F). Depending on the type of ink, after the first droplet is applied, it is not heat-fired but only dried, and then the second droplet is applied and then heat-fired to form a conductive film. ..

【0066】

Almost the same procedure can be adopted in other methods according to the present invention, which will be described later.

【0067】

In FIG. 1, the film thickness of the dots closer to the element electrode 3 is thin, and this portion becomes a portion where an electron emitting portion is likely to be formed, that is, a structural latent image. Especially in the electrode edge portion, when the ratio of the thickness of the electrode and the conductive film is large, the film thickness may be particularly thin at the joint portion, and an electron emitting portion is likely to be formed adjacent to the electrode edge. May become. FIG. 2 shows a case where a wide conductive film is formed with the same configuration as that of FIG.

【0068】

As a result of a preliminary study on how much difference the thick part and the thin part should have to control the position of the electron emitting part, it is certain that the dot film thickness is more than doubled. It turned out that it can be controlled. Depending on the material and shape of the substrate, element electrode, and conductive film, control may be possible even if the film thickness ratio is less than this, and the above conditions cannot be said to be absolute.

【0069】

FIG. 3 shows a method of forming thin dots near the center of the device electrode gap. It can be formed in the same manner as in the above case.

【0070】

In FIG. 4, the center of the dots of the conductive film is shifted from the center of the element electrode gap to make the width of the conductive film near the edge of the element electrode 3 the narrowest, so that the electron emitting portion is in the vicinity of this portion. This is the case when it is easy to form. Assuming that the radius of the dots is R, the electrode gap is L, and the amount of deviation from the center of the electrode gap at the center of the dots is δL, the width W of the conductive film at the edge positions of the element electrodes 2 and 3 is W.₁ And W₂ Is [0071]

[Number 3]

<img file="JPH1069850A_D0001.tif" />Can be expressed as. Therefore, the condition that the electron emitting part is surely formed near the edge of the element electrode 3, (W₁ / W₂ ) 2 [0072]

[Number 4]

<img file="JPH1069850A_D0002.tif" />Will be. ΔL may be determined so as to satisfy this condition.

【0073】

Further, even when a plurality of dots are partially overlapped in a direction perpendicular to the direction connecting the pair of element electrodes to form a conductive film, the value of δL satisfying the above condition can be determined by the diameter of one dot. Good.

【0074】

Next, a method of forming a composition latent image will be described. As schematically shown in FIG. 5, a plurality of dots are formed in the direction connecting the pair of element electrodes. The dots formed at this time become a portion 4-1 of the conductive film having a relatively low resistance and a portion 4-2 of the conductive film having a relatively high resistance after undergoing a treatment such as firing.

【0075】

There are several ways to make the resistances different, as described above. The first method is to form dots with a conductive film-forming ink containing a compound of a metal that is relatively difficult to oxidize and a metal that is relatively easy to oxidize, and to form a conductive film made of a metal that is relatively difficult to oxidize. This is a method of forming a conductive film portion (4-2) composed of a portion (4-1) and a metal oxide that is relatively easily oxidized. For example, Pt is used as a metal that is relatively difficult to oxidize, and Pd is used as a metal that is relatively easily oxidized, to form a conductive film composed of the metal Pt and the oxidized Pd (PdO). The metal compound may be thermally decomposed by forming dots using an ink for forming a conductive film containing each metal compound and heat-treating in an appropriate oxidizing atmosphere, or in a non-oxidizing atmosphere, respectively. Pd may be oxidized by once converting it into a metal by thermal decomposition and then heat-treating it in an appropriate oxidizing atmosphere.

【0076】

The second method uses a conductive film-forming ink containing metal compounds having the same metal element but different thermal decomposition temperatures, and is heat-treated under appropriate conditions so that one is a metal and the other is a metal. This is a method of using a metal oxide. At this time, if the heat treatment is continued for a long time, both of them become metal oxides, but if the heating conditions are set appropriately, the one having a lower thermal decomposition temperature is made into an oxide, and the other is made into a metal by thermal decomposition. The metal can be obtained by terminating the treatment before the oxidation proceeds.

【0077】

In the third method (the configuration of the element in this case is different from that shown in FIG. 5), the reducing agent is preliminarily placed in a part of the element electrode gap, for example, in the vicinity of both electrodes, by an inkjet device. By forming a conductive film on the conductive film and heat-treating it, a portion having the reducing agent is formed into a metal film and the other portion is formed into a metal oxide film. As a result, the conductive film becomes a metal near the element electrode and a metal oxide near the center, and a composition latent image is formed in the center.

【0078】

The fourth method is to form dots made of different substances as shown in Fig. 6, and to make the overlapping part of the two dots (hereinafter referred to as "intersection") an alloy of both substances. The resistance of this part is made larger than that of the remaining part. In order to obtain a sufficient effect of controlling the position of the electron emitting portion, a combination of materials such that the resistivity of the alloy formed at the intersection is higher than the resistivity of the metal other than the intersection by about an order of magnitude or more. It is desirable to use.

【0079】

3) Subsequently, a forming process is performed to form an electron emitting part. The forming process in the method of the present invention is performed by applying a voltage between a pair of element electrodes and passing an electric current through the conductive film formed in the above step. When a voltage is applied between the element electrodes 2 and 3 using a power source (not shown) and a current is passed through them, an electron emitting portion 5 having a changed structure is formed at a portion of the conductive film 4 where the latent image is formed. According to the energization forming, a portion of the conductive film 4 whose structure has changed such as fracture, deformation or alteration is locally formed. The site constitutes the electron emitting unit 5. FIG. 21G shows a state in which an electron emitting portion is formed in a portion of the conductive film having a thin film thickness, particularly in a portion adjacent to the element electrode 3. Needless to say, the position and structure of the latent image differ depending on each of the above-mentioned methods, and are not limited to those shown in FIG. 20G.

【0080】

Examples of the voltage waveform of the energization forming are shown in FIGS. 7a and 7a and 7b. The voltage waveform is preferably a pulse waveform. There are two methods, one is a method shown in FIG. 7a in which a pulse having a constant pulse peak value is continuously applied, and the other is a method shown in FIG. 7b in which a voltage pulse is applied while increasing the pulse peak value.

【0081】

T1 and T2 in FIG. 7a are the pulse width and pulse interval of the voltage waveform. Normally, T1 is set in the range of 1 μsec to 10 msec, and T2 is set in the range of 10 μsec to 100 msec. The peak value of the triangular wave (peak voltage at the time of energization forming) is appropriately selected according to the form of the electron emitting element. Under such conditions, for example, a voltage is applied for several seconds to several tens of minutes. The pulse waveform is not limited to the triangular wave, and a desired waveform such as a rectangular wave can be adopted.

【0082】

T1 and T2 in FIG. 7b can be similar to those shown in FIG. 7a. The peak value of the triangular wave (peak voltage at the time of energization forming) can be gradually increased by, for example, about 0.1 V step.

【0083】

The end of the energization forming process can be detected by measuring the current by applying a voltage that does not locally destroy or deform the conductive film 4 during the pulse interval T2. For example, the element current flowing by applying a voltage of about 0.1 V is measured, the resistance value is obtained, and when a resistance of, for example, 1 MΩ or more is shown, the energization forming is terminated.

【0084】

4) It is preferable to perform a process called an activation step on the element after forming. The activation step is a step in which the element current If and the emission current Ie are significantly changed by this step.

【0085】

The activation step can be performed, for example, by repeating the application of pulses in the same manner as the energization forming in an atmosphere containing a gas of an organic substance. This atmosphere can be formed by using the organic gas remaining in the atmosphere when the inside of the vacuum vessel is exhausted by using, for example, an oil diffusion pump or a rotary pump, and the atmosphere is once sufficiently exhausted by an ion pump or the like. It can also be obtained by introducing a suitable organic gas into the vacuum. The gas pressure of the organic substance at this time is appropriately set depending on the case because it differs depending on the above-mentioned application form, the shape of the vacuum vessel, the type of the organic substance, and the like. Suitable organic substances include aliphatic hydrocarbons such as alkanes, alkenes and alkynes, aromatic hydrocarbons, alcohols, aldehydes, ketones, amines, phenols, carboxylic acids, sulfonic acids and the like. Can be mentioned, specifically, methane, ethane, propane, etc. C_n H_{2n + 2}Saturated hydrocarbons represented by, ethylene, propylene, etc. C_n H_2nUnsaturated hydrocarbons, benzene, toluene, methanol, ethanol, formaldehyde, acetaldehyde, acetone, methyl ethyl ketone, methyl amine, ethyl amine, phenol, formic acid, acetic acid, propionic acid, etc., or mixtures thereof. it can. By this treatment, carbon or a carbon compound is deposited on the device from the organic substance existing in the atmosphere, and the device current If and the emission current Ie change remarkably.

【0086】

The end determination of the activation step is appropriately performed while measuring the element current If and the emission current Ie. The pulse width, pulse interval, pulse peak value, etc. are set as appropriate.

【0087】

Carbon and carbon compounds include, for example, graphite (including so-called HOPG, PG, GC, HOPG has a crystal structure of almost perfect graphite, PG has a crystal grain of about 20 nm and the crystal structure is slightly disordered, and GC has a crystal grain. Is about 20 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 fine crystals of graphite), and the film thickness is 50 nm or less. It is preferably in the range of 30 nm or less, and more preferably in the range of 30 nm or less.

【0088】

5) It is preferable that the electron emitting element obtained through such a step undergoes a stabilizing step. This step is a step of exhausting the organic substance in the vacuum vessel. As the vacuum exhaust device for exhausting the vacuum container, 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. Specific examples thereof include vacuum exhaust devices such as soap pumps and ion pumps.

【0089】

When an oil diffusion pump is used as an exhaust device and an organic gas derived from an oil component generated from the oil diffusion pump is used in the activation step, it is necessary to keep the partial pressure of this component as low as possible. The partial pressure of the organic components in the vacuum vessel is 1 × 10 at the partial pressure at which the above carbon and carbon compounds are hardly newly deposited.^-6Pa or less is preferable, and 1 × 10^-8Pa or less is particularly preferable. Further, when exhausting the inside of the vacuum vessel, it is preferable to heat the entire vacuum vessel to facilitate exhaustion of the organic substance molecules adsorbed on the inner wall of the vacuum vessel and the electron emitting element. The heating conditions at this time are 80 to 250 ° C, preferably 150 ° C or higher, and it is desirable to process for as long as possible, but the treatment is not particularly limited to these conditions, and the size and shape of the vacuum vessel and the electron emitting element It is carried out under the conditions appropriately selected according to various conditions such as the configuration. It is necessary to keep the pressure inside the vacuum vessel as low as possible, 1 to 3 x 10^-5Pa or less is preferable, and 1.3 × 10^-6Pa or less is particularly preferable.

【0090】

The atmosphere at the time of driving after the stabilization step is preferably maintained at the end of the stabilization treatment, but is not limited to this, and if the organic substances are sufficiently removed, the degree of vacuum is high. Even if it is slightly lowered, it can maintain sufficiently stable characteristics.

【0091】

By adopting such a vacuum atmosphere, it is possible to suppress the deposition of new carbon or carbon compounds, and H adsorbed on a vacuum vessel or substrate.₂ O, O₂ As a result, the element current If and the emission current Ie are stable.

【0092】

The basic characteristics of the electron emitting device to which the present invention can be applied obtained through the above steps will be described with reference to FIGS. 8 and 9.

【0093】

FIG. 8 is a schematic view showing an example of a vacuum processing device, and this vacuum processing device also has a function as a measurement evaluation device. Also in FIG. 8, the same parts as those shown in FIGS. 1 to 6 are designated by the same reference numerals as those shown in FIGS. 1 to 6. In FIG. 8, 11 is a vacuum vessel and 12 is an exhaust pump. An electron emitting element is arranged in the vacuum vessel 11. That is, 1 is a substrate constituting an electron emitting element, 2 and 3 are element electrodes, 4 is a conductive film, and 5 is an electron emitting part. 13 is a power supply for applying the element voltage Vf to the electron emitting element, 14 is an ammeter for measuring the element current If flowing through the conductive film 4 between the element electrodes 2 and 3, and 15 is the electron emitting part 5 of the element. It is an anode electrode for capturing the emission current Ie emitted more. 16 is a high-voltage power supply for applying a voltage to the anode electrode 15, and 17 is an ammeter for measuring the emission current Ie emitted from the electron emission section 5 of the element. As an example, the voltage of the anode electrode can be set in the range of 1 kV to 10 kV, and the distance H between the anode electrode and the electron emitting element can be set in the range of 2 mm to 8 mm.

【0094】

The vacuum vessel 11 is provided with equipment necessary for measurement in a vacuum atmosphere, such as a vacuum gauge (not shown), so that measurement and evaluation can be performed in a desired vacuum atmosphere. The exhaust pump 12 is composed of a normal high vacuum device system including a turbo pump and a rotary pump, and an ultra high vacuum device system including an ion pump and the like. The entire vacuum processing apparatus on which the substrate shown here is arranged can be heated by a heater (not shown). Therefore, by using this vacuum processing apparatus, the steps after the above-mentioned energization forming can also be performed.

【0095】

FIG. 9 is a diagram schematically showing the relationship between the emission current Ie, the element current If, and the element voltage Vf measured by using the vacuum processing apparatus shown in FIG. In FIG. 9, since the emission current Ie is significantly smaller than the element current If, it is shown in arbitrary units. Both the vertical and horizontal axes are linear scales.

【0096】

As is clear from FIG. 9, the electron emitting element to which the present invention can be applied has three characteristic characteristics with respect to the emission current Ie.

【0097】

That is, (i) When an element voltage higher than a certain voltage (called a threshold voltage, Vth in FIG. 9) is applied to this device, the emission current Ie increases sharply, while the emission current is less than the threshold voltage Vth. Almost no Ie is detected. That is, it is a non-linear element having a clear threshold voltage Vth with respect to the emission current Ie.

【0098】

(ii) Since the emission current Ie depends on the element voltage Vf for monotonically increasing above the threshold voltage Vth, the emission current Ie can be controlled by the element voltage Vf.

【0099】

(iii) The emitted charge captured by the anode electrode 15 depends on the time when the element voltage Vf is applied. That is, the amount of charge captured by the anode electrode 15 can be controlled by the time when the element voltage Vf is applied.

【0100】

As understood from the above description, the surface-conduction electron emitting element to which the present invention can be applied can easily control the electron emitting characteristics according to the input signal. Utilizing this property, it can be applied to various fields such as an electron source composed by arranging a plurality of electron emitting elements and an image forming apparatus.

【0101】

In FIG. 9, an example in which the element current If monotonically increases with respect to the element voltage Vf (hereinafter referred to as MI characteristic) is shown by a solid line. The element current If may exhibit a voltage-controlled negative resistance characteristic (hereinafter referred to as VCNR characteristic) with respect to the element voltage Vf (not shown). These characteristics can be controlled by controlling the above-mentioned steps.

【0102】

The electron source and the image forming apparatus to which the present invention can be applied are described below. A plurality of electron emitting elements to which the present invention can be applied can be arranged on a substrate to form, for example, an electron source or an image forming apparatus.

【0103】

Various arrangements of electron emitting elements can be adopted. As an example, a large number of electron emitting elements arranged in parallel are individually connected at both ends, a large number of rows of electron emitting elements are arranged (called a row direction), and a direction perpendicular to this wiring (called a column direction). There is a ladder-like arrangement in which electrons from the electron emitting element are controlled and driven by a control electrode (also referred to as a grid) arranged above the electron emitting element. Separately, a plurality of electron emitting elements are arranged in a matrix in the X and Y directions, and one of the electrodes of the plurality of electron emitting elements arranged in the same row is commonly connected to the wiring in the X direction, and the same. An example is one in which the other of the electrodes of a plurality of electron emitting elements arranged in a row is commonly connected to a wiring in the Y direction. Such a thing is a so-called simple matrix arrangement. First, the simple matrix arrangement will be described in detail below.

【0104】

The electron emitting element to which the manufacturing method of the present invention can be applied has the characteristics (i) to (iii) as described above. That is, the emitted electrons from the electron emitting element can be controlled by the peak value and width of the pulsed voltage applied between the electrodes of the opposing elements above the threshold voltage. On the other hand, below the threshold voltage, almost no electrons are emitted. According to this characteristic, even when a large number of electron emitting elements are arranged, if a pulsed voltage is appropriately applied to each element, the electron emitting element is selected and the electron emission amount is controlled according to the input signal. it can.

【0105】

Hereinafter, a substrate obtained by arranging a plurality of electron emitting elements to which the present invention can be applied based on this principle will be described with reference to FIG. In FIG. 10, 21 is a board, 22 is an X-direction wiring, and 23 is a Y-direction wiring. 24 is an electron emitting element and 25 is a connection.

【0106】

The m X-direction wirings 22 are composed of Dx1, Dx2, ...., Dxm, and can be composed of a conductive metal or the like formed by a vacuum deposition method, a printing method, a sputtering method, or the like. The wiring material, film thickness, and width are appropriately set. The Y-direction wiring 23 consists of n wirings of Dy1, Dy2, ...., and Dyn, and is formed in the same manner as the X-direction wiring 22. An interlayer insulating layer (not shown) is provided between these m X-direction wires 22 and n Y-direction wires 23, and both are electrically separated (m and n are both). Positive integer).

【0107】

The interlayer insulating layer (not shown) is a SiO formed by a vacuum deposition method, a printing method, a sputtering method, or the like.₂ Etc. For example, the film thickness and material are formed on the entire surface or a part of the substrate 21 on which the X-direction wiring 22 is formed in a desired shape, and in particular, the film thickness and material can withstand the potential difference at the intersection of the X-direction wiring 22 and the Y-direction wiring 23. , The manufacturing method is set appropriately. The X-direction wiring 22 and the Y-direction wiring 23 are respectively drawn out as external terminals.

【0108】

The pair of electrodes (not shown) constituting the electron emitting element 24 are electrically connected by m X-direction wires 22, n Y-direction wires 23, and a wire 25 made of a conductive metal or the like.

【0109】

The materials that make up the wiring 22 and the wiring 23, the materials that make up the connection 25, the materials that make up the connection 25, and the materials that make up the pair of element electrodes are all the same, even if some or all of the constituent elements are the same. Each may be different. These materials are appropriately selected from, for example, the materials of the device electrodes described above. When the material constituting the element electrode and the wiring material are the same, the wiring connected to the element electrode can also be said to be the element electrode.

【0110】

A scanning signal applying means (not shown) for applying a scanning signal for selecting a row of electron emitting elements 24 arranged in the X direction is connected to the X-direction wiring 22. On the other hand, the Y-direction wiring 23 is connected to a modulation signal generating means (not shown) for modulating each row of the electron emitting elements 24 arranged in the Y direction according to the input signal. The drive voltage applied to each electron emitting element is supplied as a difference voltage between the scanning signal and the modulation signal applied to the element.

【0111】

In the above configuration, individual elements can be selected and independently driven by using simple matrix wiring.

【0112】

An image forming apparatus configured by using an electron source having such a simple matrix arrangement will be described with reference to FIGS. 11, 12, and 14. FIG. 11 is a schematic view showing an example of a display panel of the image forming apparatus, and FIG. 12 is a schematic diagram of a fluorescence film used in the image forming apparatus of FIG. FIG. 14 is a block diagram showing an example of a drive circuit for displaying according to an NTSC type television signal.

【0113】

In FIG. 11, 21 is a substrate on which a plurality of electron emitting elements are arranged, 31 is a rear plate on which the substrate 21 is fixed, and 36 is a face plate in which a fluorescence film 34, a metal back 35, etc. are formed on the inner surface of a glass substrate 33. .. Reference numeral 32 denotes a support frame, and the rear plate 31 and the face plate 36 are joined to the support frame 32 by using frit glass having a low melting point or the like.

【0114】

24 corresponds to the electron emitting part 5 in FIG. Reference numerals 22 and 23 are X-direction wiring and Y-direction wiring connected to a pair of element electrodes of the electron emitting element.

【0115】

The outer enclosure 37 is composed of a face plate 36, a support frame 32, and a rear plate 31, and is sealed and configured by firing in the air or nitrogen in a temperature range of 400 to 500 degrees for 10 minutes or more. Will be done. Since the rear plate 31 is provided mainly for the purpose of reinforcing the strength of the substrate 21, if the substrate 21 itself has sufficient strength, the separate rear plate 31 can be omitted. That is, the support frame 32 may be directly sealed to the substrate 21, and the enclosure 37 may be composed of the face plate 36, the support frame 32, and the substrate 21. On the other hand, by installing a support (not shown) called a spacer between the face plate 36 and the rear plate 31, it is possible to construct an enclosure 37 having sufficient strength against atmospheric pressure.

【0116】

FIG. 12 is a schematic view showing a fluorescence film. In the case of monochrome, the fluorescent film 34 can be composed only of a fluorescent body. In the case of a color fluorescent film, it can be composed of a black conductive material 41 called a black stripe (Fig. 12A) or a black matrix (Fig. 12B) and a fluorescent body 42 depending on the arrangement of the fluorescent bodies. The purpose of providing the black stripe or black matrix is to make the color mixing etc. inconspicuous by blackening the painted part between each of the required three primary color fluorescent bodies 42 in the case of color display, and to make the light film inconspicuous. The purpose is to suppress the decrease in contrast due to the reflection of external light in 34. As the material of the black stripe or the black matrix, in addition to the commonly used material containing graphite as a main component, a material having conductivity and less light transmission and reflection can be used.

【0117】

As a method of applying the phosphor to the glass substrate 33, a precipitation method, a printing method or the like can be adopted regardless of monochrome or color. A metal back 35 is usually provided on the inner surface side of the fluorescence film 34. The purpose of providing the metal back is to improve the brightness by specularly reflecting the light on the inner surface side of the emission of the fluorescent body toward the face plate 36 side, and to act as an electrode for applying the electron beam acceleration voltage. , Protecting the phosphor from damage caused by the collision of negative ions generated in the enclosure. The metal back can be produced by smoothing the inner surface of the fluorescent film (usually called "filming") after producing the fluorescent film, and then depositing A1 by vacuum vapor deposition or the like.

【0118】

The face plate 36 may be provided with a transparent electrode (not shown) on the outer surface side of the fluorescence film 34 in order to further enhance the conductivity of the fluorescence film 34.

【0119】

In the case of color, it is necessary to make each color phosphor and the electron emitting element correspond to each other when performing the above-mentioned sealing, and sufficient alignment is indispensable.

【0120】

An example of the manufacturing method of the image forming apparatus shown in FIG. 11 will be described below. FIG. 13 is a schematic view showing an outline of the apparatus used in this step. The image forming apparatus 51 is connected to the vacuum chamber 53 via the exhaust pipe 52, and further connected to the exhaust device 55 via the gate valve 54. The vacuum chamber 53 is equipped with a pressure gauge 56, a quadrupole mass spectrometer 57, and the like in order to measure the internal pressure and the partial pressure of each component in the atmosphere. Since it is difficult to directly measure the pressure inside the enclosure 37 of the image display device 51, the pressure inside the vacuum chamber 53 is measured to control the processing conditions.

【0121】

A gas introduction line 58 is connected to the vacuum chamber 53 in order to further introduce necessary gas into the vacuum chamber to control the atmosphere. An introduction substance source 60 is connected to the other end of the gas introduction line 58, and the introduction substance is stored in an ampoule, a cylinder, or the like. In the middle of the gas introduction line, an introduction amount control means 59 for controlling the rate at which the introduced substance is introduced is provided. Specifically, as the introduction amount control means 59, a valve capable of controlling the escape flow rate such as a slow leak valve, a mass flow controller, or the like can be used depending on the type of the introduced substance.

【0122】

The inside of the outer enclosure 37 is exhausted by the device shown in FIG. 13 to perform forming. At this time, for example, as shown in FIG. 14, the Y-direction wiring 23 is connected to the common electrode 61, and a voltage pulse is simultaneously applied to the element 24 connected to one of the X-direction wirings 22 by the power supply 62. , Forming can be performed. Conditions such as the shape of the pulse and the determination of the end of processing may be selected according to the method described above for forming individual elements. It is also possible to collectively form elements connected to a plurality of X-direction wirings by sequentially applying (scrolling) pulses that are out of phase to the plurality of X-direction wirings. In FIG. 14, 63 shows a resistor for current measurement, and 64 shows an oscilloscope for current measurement.

【0123】

After the forming is completed, the activation step is performed. After sufficiently exhausting the inside of the outer enclosure 37, organic substances are introduced from the gas introduction line 58. Alternatively, as a method for activating the individual element, as described above, the organic substance that remains in the vacuum atmosphere by first exhausting with an oil diffusion pump or a rotary pump may be used. In addition, substances other than organic substances may be introduced as needed. By applying a voltage to each electron emitting element in the atmosphere containing the organic substance thus formed, carbon or a carbon compound, or a mixture of both, is deposited on the electron emitting part, and the amount of electron emission is drastically reduced. The rise is the same as in the case of individual elements. The voltage application method at this time may be to apply simultaneous voltage pulses to the elements connected to one directional wiring by the same connection as in the case of the above forming.

【0124】

After the activation step is completed, it is preferable to carry out the stabilization step as in the case of the individual device.

【0125】

After heating the outer enclosure 37 and holding it at 80 to 250 ° C, exhausting it through the exhaust pipe 52 by an exhaust device 55 that does not use oil such as an ion pump or soap pump to create an atmosphere with sufficiently little organic substances. , Heat the exhaust pipe with a burner to melt it and seal it. Gettering can also be performed to maintain the pressure of the enclosure 37 after sealing. This is to heat a getter (not shown) arranged at a predetermined position in the enclosure 37 by heating using resistance heating or high frequency heating immediately before or after sealing the enclosure 37. This is a process for forming a vapor-deposited film. The getter usually contains Ba or the like as a main component, and maintains the atmosphere inside the enclosure 37 by the adsorption action of the vapor deposition film.

【0126】

Next, a configuration example of a drive circuit for displaying a television based on an NTSC television signal on an image forming apparatus configured by using an electron source arranged in a simple matrix will be described with reference to FIG. In FIG. 15, 71 is an image forming apparatus, 72 is a scanning circuit, 73 is a control circuit, and 74 is a shift register. 75 is a line memory, 76 is a synchronous signal separation circuit, 77 is a modulation signal generator, and Vx and Va are DC voltage sources.

【0127】

The image forming apparatus 71 is connected to an external electric circuit via terminals Dox1 to Doxm, terminals Doy1 to Doyn, and a high-voltage terminal Hv. The terminals Dox1 to Doxm are scans for sequentially driving an electron source provided in the image forming apparatus, that is, a group of electron emitting elements matrix-wired in a matrix of M rows and N columns, one row at a time (N elements). A signal is applied.

【0128】

A modulation signal for controlling the output electron beam of each element of the one-line electron emitting element selected by the scanning signal is applied to the terminals Dy1 to Dyn. A DC voltage of, for example, 10 kV is supplied to the high-voltage terminal Hv from the DC voltage source Va, because the electron beam emitted from the electron emitting element is provided with sufficient energy to excite the phosphor. Acceleration voltage.

【0129】

The scanning circuit 72 will be described. The circuit is equipped with M switching elements inside (schematically shown by S1 to Sm in the figure). Each switching element selects either the output voltage of the DC voltage source Vx or 0V (ground level), and is electrically connected to the terminals Dx1 to Dxm of the image forming apparatus 71. Each of the switching elements S1 to Sm operates based on the control signal Tscan output by the control circuit 73, and can be configured by combining switching elements such as FETs, for example.

【0130】

In the case of this example, the DC voltage source Vx is such that the drive voltage applied to the unscanned element is less than the electron emission threshold voltage based on the characteristics of the electron emission element (electron emission threshold voltage). It is set to output a constant voltage.

【0131】

The control circuit 73 has a function of matching the operation of each part so that an appropriate display is performed based on an image signal input from the outside. The control circuit 73 generates Tscan, Tsft, and Tmry control signals for each unit based on the synchronization signal Tsync sent from the synchronization signal separation circuit 76.

【0132】

The synchronous signal separation circuit 76 is a circuit for separating a synchronous signal component and a luminance signal component from an NTSC type television signal input from the outside, and can be configured by using a general frequency separation (filter) circuit or the like. The synchronization signal separated by the synchronization signal separation circuit 76 consists of a vertical synchronization signal and a horizontal synchronization signal, which are shown here as Tsync signals for convenience of explanation. The luminance signal component of the image separated from the television signal is represented as a DATA signal for convenience. The DATA signal is input to the shift register 74.

【0133】

The shift register 74 is for serial / parallel conversion of the DATA signal serially input in time series for each line of the image, and operates based on the control signal Tsft sent from the control circuit 73. (That is, the control signal Tsft can be said to be the shift clock of the shift register 74). The serial / parallel-converted image data for one line (corresponding to the drive data for the electron emitting element N element) is output from the shift register 74 as N parallel signals of Id1 to Idn.

【0134】

The line memory 75 is a storage device for storing data for one image line only for a required time, and appropriately stores the contents of Id1 to Idn according to the control signal Tmry sent from the control circuit 73. The stored contents are output as I'd1 to I'dn and input to the modulation signal generator 77.

【0135】

The modulation signal generator 77 is a signal source for appropriately driving and modulating each of the electron emitting elements according to each of the image data I'd1 to I'dn, and the output signal thereof is an image through terminals Doy1 to Doyn. It is applied to the electron emitting element in the forming device 71.

【0136】

As described above, the electron emitting element to which the present invention can be applied has the following basic characteristics with respect to the emission current Ie. That is, there is a clear threshold voltage Vth for electron emission, and electron emission occurs only when a voltage equal to or higher than Vth is applied. For a voltage equal to or higher than the electron emission threshold, the emission current also changes according to the change in the voltage applied to the device. From this, when a pulsed voltage is applied to this element, for example, when a voltage lower than the electron emission threshold is applied, no electron emission occurs, but when a voltage equal to or higher than the electron emission threshold is applied. Outputs an electron beam. At that time, it is possible to control the intensity of the output electron beam by changing the peak value Vm of the pulse. In addition, it is possible to control the total amount of charge of the output electron beam by changing the pulse width Pw.

【0137】

Therefore, as a method of modulating the electron emitting element according to the input signal, a voltage modulation method, a pulse width modulation method, or the like can be adopted. When implementing the voltage modulation method, a voltage modulation type circuit that generates a voltage pulse of a certain length and appropriately modulates the peak value of the pulse according to the input data is used as the modulation signal generator 77. be able to.

【0138】

When implementing the pulse width modulation method, the modulation signal generator 77 is a pulse width modulation method that generates a voltage pulse with a constant peak value and appropriately modulates the width of the voltage pulse according to the input data. A circuit can be used.

【0139】

The shift register 74 and the line memory 75 can be either a digital signal type or an analog signal type. This is because the serial / parallel conversion and storage of the image signal may be performed at a predetermined speed.

【0140】

When the digital signal type is used, it is necessary to convert the output signal DATA of the synchronous signal separation circuit 76 into a digital signal, but this may be done by providing an A / D converter in the output section of the circuit 76. In this regard, the circuit used for the modulation signal generator 77 is slightly different depending on whether the output signal of the line memory 75 is a digital signal or an analog signal. That is, in the case of the voltage modulation method using a digital signal, for example, a D / A conversion circuit is used for the modulation signal generator 77, and an amplifier circuit or the like is added as needed. In the case of the pulse width modulation method, the modulation signal generator 77 includes, for example, a high-speed oscillator, a comparator that counts the number of waves output by the oscillator, and a comparison that compares the output value of the comparator with the output value of the memory. A circuit that combines a device (comparator) is used. If necessary, an amplifier for amplifying the pulse width-modulated modulated signal output by the comparator to the drive voltage of the electron emitting element can be added.

【0141】

In the case of the voltage modulation method using an analog signal, an amplifier circuit using, for example, an operational amplifier can be adopted for the modulation signal generator 77, and a level shift circuit or the like can be added as needed. In the case of the pulse width modulation method, for example, a voltage controlled oscillator circuit (VCO) can be adopted, and an amplifier for amplifying the voltage up to the drive voltage of the electron emitting element can be added as needed.

【0142】

In an image display device to which the present invention can be applied having such a configuration, electron emission occurs by applying a voltage to each electron emitting element via the terminals Dox1 to Doxm and Doy1 to Doyn outside the container. A high voltage is applied to the metal back 35 or the transparent electrode (not shown) via the high voltage terminal Hv to accelerate the electron beam. The accelerated electrons collide with the fluorescence film 34 and emit light to form an image.

【0143】

The configuration of the image forming apparatus described here is an example of the image forming apparatus to which the present invention can be applied, and various modifications can be made based on the technical idea of the present invention. Regarding the input signal, the NTSC system is mentioned, but the input signal is not limited to this, and the TV signal consisting of a larger number of scanning lines (for example, the MUSE system) other than the PAL and SECAM systems, etc. High-definition TV) system can also be adopted.

【0144】

Next, the electron source and the image forming apparatus in the ladder type arrangement will be described with reference to FIGS. 16 and 17.

【0145】

FIG. 16 is a schematic diagram showing an example of an electron source in a ladder-type arrangement. In FIG. 16, 21 is a substrate and 81 is an electron emitting element. 82 and Dx1 to Dx10 are common wiring for connecting the electron emitting element 81. A plurality of electron emitting elements 81 are arranged in parallel on the substrate 21 in the X direction (this is called an element row). A plurality of these element rows are arranged to form an electron source. By applying a drive voltage between the common wirings of each element row, each element row can be driven independently. That is, a voltage equal to or higher than the electron emission threshold is applied to the element row in which the electron beam is desired to be emitted, and a voltage lower than the electron emission threshold is applied to the element row in which the electron beam is not emitted. For the common wiring Dx2 to Dx9 between the element rows, for example, Dx2 and Dx3 can be the same wiring.

【0146】

FIG. 17 is a schematic view showing an example of a panel structure in an image forming apparatus provided with an electron source in a ladder type arrangement. 83 is a grid electrode, 84 is a hole for electrons to pass through, and 85 is an outer container terminal consisting of Dxo1, Dxo2, ...., Dxom. Reference numeral 86 is an outer container terminal composed of G1, G2, ...., Gn connected to the grid electrode 83. The major difference between the image forming apparatus shown here and the image forming apparatus having a simple matrix arrangement shown in FIG. 11 is whether or not the grid electrode 83 is provided between the substrate 21 and the face plate 36.

【0147】

In FIG. 17, a grid electrode 83 is provided between the substrate 21 and the face plate 36. The grid electrode 83 is for modulating the electron beam emitted from the electron emitting element, and allows the electron beam to pass through a striped electrode provided orthogonal to the element row of the ladder type arrangement, so that each element is used. A circular opening 84 is provided one by one corresponding to the above. The shape and installation position of the grid are not limited to those shown in FIG. For example, a large number of passage ports may be provided as openings in a mesh shape, and a grid may be provided around or in the vicinity of the electron emitting element.

【0148】

The outer container terminal 85 and the outer grid terminal 86 are electrically connected to a control circuit (not shown).

【0149】

In the image forming apparatus of this example, the modulation signals for one line of the image are simultaneously applied to the grid electrode rows in synchronization with the sequential driving (scanning) of the element rows one by one. As a result, it is possible to control the irradiation of each electron beam to the phosphor and display the image line by line.

【0150】

The image forming apparatus of the present invention can be used not only as a display device for television broadcasting, a display device for a video conferencing system, a computer, etc., but also as an image forming apparatus as an optical printer configured by using a photosensitive drum or the like. it can.

【0151】

[Example]

Hereinafter, the present invention will be described based on examples. Example 1 The configuration of the electron emitting device formed by this embodiment is the same as that schematically shown in FIG. The process of this embodiment will be described below.

【0152】

The conductive film forming ink used in this example is Ink A; Palladium acetate monoethanolamine (PAME) dissolved in water to a metal concentration of 2 wt.% Ink B; Ink A diluted 3-fold with water Prior to creating the actual electron source, the ejection conditions of the inkjet device are adjusted. That is, each of the above two types of ink is filled in an inkjet device using a piezoelectric element. Further, the same quartz as that used as a substrate for an electron source is prepared in the following step, and the above ink is discharged onto the quartz to form dots, and then heat treatment is performed at 300 ° C. for 10 minutes in the atmosphere. The thickness and diameter of the dots formed by this are measured, and the ejection conditions are such that the film thickness of the dots formed by ink A is 30 nm, the film thickness of the dots formed by ink B is 10 nm, and the diameter of the dots is approximately 20 μm. Was set.

【0153】

Process-1 After the quartz substrate was sufficiently washed and dried, a plurality of element electrode pairs and a matrix-like wiring bonded to the plurality of element electrode pairs were formed on the substrate by vacuum film formation and photolithography techniques. The element electrode was composed of Ni having a thickness of about 100 nm, the element electrode gap L was 20 μm, and the element electrode length W was 100 μm.

【0154】

Process-2 Inkjet A dots are formed by an inkjet device. These are the dots corresponding to the conductive film 4-1 in FIG. 1A. The position of the inkjet device is controlled so that the center of the dot is 5 μm from the edge of the element electrode 2 toward the element electrode 3. The dots are formed at the relevant positions of all element electrode pairs on the quartz substrate.

【0155】

Process-3 Dots of ink B are formed in the same manner. The center of the dot was set at a position of 5 μm from the edge of the element electrode 3 toward the element electrode 2. The center spacing of both dots is 10 μm.

【0156】

Process-4 Subsequently, heat treatment is performed at 300 ° C. for 10 minutes in the atmosphere. As a result, the conductive film 4 made of PdO fine particles is formed.

【0157】

Process-5 Subsequently, a forming treatment was performed to form an electron emitting portion. The pulse waveform used in this process is a triangular wave pulse in which the peak value gradually increases, as shown in FIG. 7B. All the wiring in the column direction was connected to the ground, and the pulse voltage was applied to one of the wirings in the row direction to form an electron emitting part. When the forming of all the elements in each row was completed, the same processing was performed on another row to form electron emitting parts for all the elements.

【0158】

When the electron source was observed with a scanning electron microscope (STM), it was found that in each of the elements, an electron emitting portion was formed near the element electrode edge of the dot having the thinner film thickness.

【0159】

Process-6 The electron source in which the electron emitting portion was formed was combined with members such as a face plate, a rear plate, and a support frame to form an image forming apparatus as shown in FIG. Subsequently, the electron emitting device was activated. After exhausting the inside of the outer peripheral device with a vacuum exhaust device through an exhaust pipe (not shown), acetone is introduced to reduce the pressure to 1.3 × 10.^-1Adjust so that it becomes Pa. A square wave pulse with a peak value of 16 V and a pulse width of 100 μsec is applied from the drive circuit to the row direction wiring of the electron source via the external terminal. The timing of applying the pulse to each row direction wiring was slightly shifted, and the drive circuit was set so that the pulse was repeatedly applied at a cycle of 60 Hz for the entire electron source. The pulse was applied for 30 minutes, then stopped, and the inside of the enclosure was exhausted again.

【0160】

Process-7 When the exhaust was continued while keeping the entire enclosure at about 200 ° C, the pressure was 2.7 x 10 after 10 hours.^-5It became Pa. After slowly cooling the outer enclosure while continuing to exhaust, the exhaust pipe was welded and sealed by heating with a burner. After that, a getter (not shown) installed in advance in the enclosure was heated by a high frequency to perform getter treatment.

【0161】

A voltage of 5 kV is applied to the metal back of the image forming apparatus created in this way through a high-voltage terminal, and electrons are emitted from each electron emitting element of the electron source by a simple matrix drive, and the value of the emission current Ie of each element. Was measured. The variation width of Ie of each element was 12%.

【0162】

Comparative example 1 An electron source was prepared in the same manner as in Example 1 except that the dots in step 3 were formed by ink A, and the shape of the electron emitting part was observed by SEM. In the case of this example, it was observed that the electron emitting part meandered to a width of about half of the electrode gap. In addition, an image forming apparatus was similarly prepared using this, and the electron emission characteristics were measured. As a result, the variation width of Ie of each element was 16%.

【0163】

Example 2 In this embodiment, elements having basically the same configuration as those in FIGS. 3A and 3B are created. However, the electrode gap is 140 μm, five dots with a diameter of 50 μm are arranged in the direction connecting the pair of element electrodes, and three dots are arranged in the direction perpendicular to the dots. Of these, the three dots in the center of the electrode gap are formed by ink B, and the other dots are formed by ink A. The dots of ink A were formed so that the center of the dot in contact with the element electrode was 10 μm away from the edge of the element electrode, and the center of the adjacent dot was further 25 μm away. The dots formed by ink B were formed in the center of the electrode gap. The centers were formed so as to be 25 μm apart from each other in the direction perpendicular to the direction of connecting the pair of element electrodes.

【0164】

When the result of the electron emission part by forming was observed by SEM, it was found that the meandering range of the electron emission part was formed in the width of 20 μm in the center of the electrode gap, that is, in the dots formed by the ink B. It was.

【0165】

Further, when the electron emission characteristics were measured by configuring the image forming apparatus in the same manner as in Example 1, the variation of the emission current Ie of each element was 12%.

【0166】

Comparative example 2 An image forming apparatus was created in the same manner as in Example 2 above, except that all the dots were composed of ink A. It was found from the observation by SEM that the meandering width of the electron emitting part is about half of the device electrode gap. Moreover, as a result of measuring the electron emission characteristics, the variation width of the emission current Ie was 18%.

【0167】

The size of the bright spots of the image forming apparatus of Example 2 and Comparative Example 2 was measured. In Example 2, it was about 150 μm, whereas in Comparative Example 2, it was about 200 μm. The difference of 50 μm between the two is considered to correspond to the meandering width of the formed electron emitting part.

【0168】

Example 3 The device produced by the method of this embodiment has almost the same configuration as that of the first embodiment. A conductive film was formed by using ink B for all dots, applying droplets to the same spot three times for thick dots and once for thin dots. Except for the above, the same steps as in Example 1 were carried out. The same results as in Example 1 were obtained in both the observation by SEM and the measurement of the electron emitting element characteristics.

【0169】

Examples 4 and 5 An image forming apparatus was produced by the same steps as in Examples 1 and 2 except that a bubble jet printer head (product name: BC-01, manufactured by Canon Inc.) was used as the inkjet apparatus. Each had the same shape of the electron emitting part as that prepared in Examples 1 and 2, and the same electron emitting characteristics were obtained.

【0170】

Example 6 After forming the element electrodes and wiring on the quartz substrate in the same manner as in Example 1, dots made of the above ink A were formed one by one. In this embodiment, the ejection conditions were adjusted so that the element electrode gap was 20 μm and the dot diameter was 40 μm.

【0171】

In order to ensure that the electron emitting part is formed near one of the element electrodes by preliminary examination, the ratio of the width of the conductive film at the position where the dots of the conductive film are in contact with the element electrode (W).₁ / W₂ Since it was known that () should be 2 or more, the dots were formed so that the center of the dots was shifted 7.5 μm from the center of the electrode gap toward the element electrode 2. Geometrically under this condition (W₁ / W₂ ) 2.05, which satisfies the above conditions. If the amount of deviation is smaller than this, the certainty of controlling the position of the electron emitting portion gradually decreases. On the other hand, if the amount of deviation becomes larger than this, W₂ Is rapidly reduced, and the length of the electron emitting portion is also shortened accordingly, which leads to a decrease in the amount of electron emission. Therefore, it is not preferable to unnecessarily increase the amount of deviation.

【0172】

As in Example 1, when the shape of the electron emitting portion was observed by SEM after the forming treatment, the electron emitting portion was formed near the edge of the element electrode 3 in all the electron emitting elements as intended. When the electron emission characteristics were measured, the variation width of the emission current Ie was 10%.

【0173】

Comparative example 3 An image forming apparatus was created in the same manner as in Example 6 except that the center of the dots of the conductive film was set to the center of the element electrode gap. It was observed that the electron emitting part meandered greatly in the electrode gap. In the measurement of electron emission characteristics, the variation width of the emission current Ie was 14%.

【0174】

Example 7 This example is similar to that of Example 6, but the element electrode gap is 30 μm, the dot diameter is 60 μm, and the dot center is shifted by 11 μm from the center of the element electrode gap to the element electrode 2 side. Further, five dots were formed by shifting the dots by 30 μm in a direction orthogonal to the direction connecting the pair of element electrodes. In the conductive thin film formed in this way, the dots are overlapped on the side closer to the element electrode 2, so that there is no big difference in the width of the conductive film near the edges of both element electrodes as a whole, but the conductivity is conductive. The film thickness of the sex film has a difference corresponding to the deviation from the center of the device electrode gap.

【0175】

As a result of observation by SEM after forming, it was confirmed that an electron emission part was formed near the edge of the element electrode 3 as intended as in Example 6, and an image forming apparatus was formed to measure the electron emission characteristics. As a result, the variation width of the emission current Ie was 8%.

【0176】

Example 8 The electron emitting element formed by the method of this embodiment has the configuration schematically shown in FIGS. 5A and 5B. In this embodiment, the following two types of conductive film forming inks are used as the material for the droplets. Ink C; Tetraammine Platinum (II) nitrate dissolved in water so that the metal concentration is 2 wt.% Ink D; same as Ink A [0177]

Process-1 Element electrodes 2 and 3 made of Pt were produced by offset printing on the cleaned quartz substrate. The ink used is Pt registered paste. After forming the shape of the electrode with the paste, it was dried at about 70 ° C. and fired in the air at about 580 ° C. to form the element electrode. The thickness of the element electrode is about 100 nm, and the element electrode gap is 30 μm. However, each element is configured independently and does not have matrix wiring.

【0178】

Process-2 The printer head of the bubble jet printer (product name: BC-01, manufactured by Canon Inc.) was filled with the above two types of ink and applied onto the substrate. Then, at 300 ° C in the air for 10 minutes. By performing the heat treatment of, dots 4-1 and 4-2 composed of Pt and PdO were formed.

【0179】

Process-3 An electron emitting element is set in a vacuum device having the same configuration as schematically shown in Fig. 8, and the inside of the vacuum chamber is exhausted so that the pressure is 1.3 × 10.^-4The Pa was set, and the same pulse voltage as in Example 1 was applied to perform the forming process.

【0180】

Process-4 Subsequently, acetone was introduced into the vacuum device from a gas introduction line (not shown), and the pressure was 1.3 × 10.^-1Let's say Pa. A square wave pulse with a peak value of 18 V, a pulse width of 100 μsec, and a pulse interval of 10 msec was applied between the element electrodes to perform activation treatment. After 30 minutes, when the increase in the element current tended to saturate, the application of the pulse voltage was stopped, and the inside of the vacuum device was exhausted again.

【0181】

Process-5 When the vacuum device was kept at about 200 ° C by the heater and the exhaust was continued, the pressure was 2.7 × 10 in 10 hours.^-5It became Pa. The heater was turned off and the vacuum device was slowly cooled.

【0182】

The electron emission characteristics of the above device were measured. The pulse voltage applied to the device is a square wave pulse with a peak value of 16V. The gap between the device and the anode electrode was 4 mm, and the anode voltage was 1 kV.

【0183】

When all the elements on the substrate were measured in the same manner, the variation of the emission current Ie was 7%. When the above-mentioned element was observed by SEM after the measurement was completed, it was found that an electron emitting portion was formed near the edge of the element electrode 3 in any of the elements.

【0184】

Comparative example 4 An element was produced by the same process as in Example 8 except that only the above ink D was used. As a result of performing the measurement in the same manner, the variation of the emission current Ie was 14%. In addition, when the electron emission part was observed by SEM after the measurement was completed, it was found that the electron emission part was meandering greatly as in the case of Comparative Example 1.

【0185】

Example 9 In this embodiment, the above ink D and Ink E; Palladium acetate-bis (N-butylethanolamine) (PADBE) 1.28 g dissolved in 12 g of water (metal concentration 2 wt.%) Was used as a raw material for droplets for dot formation. When the state of thermal decomposition of both during heat treatment in the atmosphere was investigated in advance, PAME decomposed into metal at around 170 ° C, PdO began to be generated at 280 ° C, and PADBE decomposed into metal at around 145 ° C. It started to grow and became almost PdO at 255 ° C.

【0186】

Originally, the temperature at which the metal Pd changes to PdO should not depend on the starting material, but the above difference occurred when the Pd compound changed to metal Pd faster, and the subsequent heat treatment time It is thought that this is because there was a difference in the reaction rate until it changed to PdO due to the substantial increase in length and the difference in microscopic morphology when it became metal Pd.

【0187】

Multiple pairs of element electrodes made of Au were formed on a thoroughly washed and dried quartz substrate. The device electrode gap was set to 20 μm. Using the above ink, dots 4-1 with ink E and dots 4-2 with ink D were formed between the element electrodes in the same manner as in Example 8, and heat treatment was performed at 270 ° C for 10 minutes to form the conductive film 4. .. However, in this embodiment, all the dots are formed so that the four dots are shifted from each other in the direction perpendicular to the direction connecting the pair of element electrodes so that the adjacent dots partially overlap each other. The plan view has a structure similar to that of FIG. 2A described above.

【0188】

Subsequently, the forming treatment and the activation treatment were carried out by the same method as in Example 8. However, the pressure of acetone during the activation process is 1 × 10.^-2Pa, and the peak value of the applied pulse was boosted from 0V to 14V at 5V / min and then fixed at 14V. After continuing to exhaust for 10 hours while keeping the vacuum device at about 200 ° C, the heater was turned off and the mixture was slowly cooled.

【0189】

When the electron emission characteristics were measured in the same manner as in Example 8, almost the same measurement results as in Example 8 were obtained. As a result of observing the morphology of the device by SEM after the measurement was completed, it was found that an electron emitting portion was formed near the edge of the device electrode 3 as in Example 8.

【0190】

Example 10 In this embodiment, the above ink D and Ink F; Palladium acetate-di (N-butylethanolamine) (PABE) 0.84 g dissolved in 12 g of water Was used. Heat treatment experiments in the atmosphere confirmed that PABE decomposed into metallic Pd at 145 ° C and changed to almost PdO at 245 ° C.

【0191】

The configuration of the element created in this embodiment is similar to that shown in FIG. 3A in the plane, in which the dots in the center row are formed by ink F and the other dots are formed by ink D. Each dot is formed using an inkjet device in the same manner as in Example 8, and after heat treatment at 260 ° C. for 10 minutes in the air, forming treatment and activation treatment are performed in the same manner as in Example 8, and then a vacuum device is used. By exhausting while heating, a high vacuum was realized and the electron emission characteristics were measured. As a result, almost the same result as in Example 8 was obtained.

【0192】

After the measurement was completed, the morphology was observed by SEM, and it was found that an electron emitting part was formed in the center of the conductive film.

【0193】

Example 11 The electron emitting element produced in this embodiment has the same configuration as that in Example 9. In this example, Ink G; Palladium acetate-monobutanolamine (PAMB) dissolved in water, metal concentration 2 wt.% Ink H; Palladium acetate-bis (N, N-diethylethanolamine) (PADEE) dissolved in water, metal concentration 2 wt.% Was used. When the characteristics of thermal decomposition were investigated, PAMB decomposed into metallic Pd at around 180 ° C and changed to PdO at 260 ° C. PADEE decomposed into metallic Pd at 140 ° C and changed to PdO at 230 ° C.

【0194】

The device was prepared in the same manner as in Example 9, and the heat treatment for forming the conductive film was performed in the air at 240 ° C. for 10 minutes. The forming treatment, the activation treatment, and the exhaust in the vacuum apparatus were performed in the same manner as in Example 9, and the electron emission characteristics were measured.

【0195】

The result of the measurement was almost the same as that of Example 9. The results of morphological observation by SEM were also the same as in Example 9.

【0196】

Example 12 The configuration of the element produced by the method of this embodiment is the same as that of the tenth embodiment. The conductive film forming ink used in this example is Ink I; Palladium acetate-monopropanolamine (PAMP) dissolved in water, metal concentration 2 wt.% Ink J; Palladium acetate-bis (N, N-dimethylethanolamine) (PADME) dissolved in water, metal concentration 2 wt.% Is.

【0197】

When the characteristics of thermal decomposition were investigated, PAMP decomposed into metallic Pd at around 180 ° C and changed to PdO at 270 ° C. PADME decomposed into metallic Pd at 120 ° C and changed to PdO at 230 ° C.

【0198】

The device was prepared in the same manner as in Example 10, and the heat treatment for forming the conductive film was performed in the air at 240 ° C. for 10 minutes. In the same manner as in Example 9, the forming treatment, the activation treatment, and the exhaust in the vacuum apparatus were performed, and the electron emission characteristics were measured.

【0199】

The result of the measurement was almost the same as that of Example 9. The results of morphological observation by SEM were also the same as in Example 9.

【0200】

Example 13 A pattern of element electrodes is formed by offset printing using platinum resinate paste as ink on a sufficiently washed quartz substrate, dried at 70 ° C, and then fired at about 580 ° C to form an element electrode consisting of Pt. Was formed in multiple pairs.

【0201】

Subsequently, the inkjet device was filled with a 1 wt.% Water dispersion of carbon fine particles Furness Black (HAF, average particle size 30 nm) (containing 0.1 wt.% Of a surfactant to improve dispersibility). This droplet was applied between the element electrodes. At this time, the carbon fine particle dispersion liquid was slightly sucked into the element electrodes formed by firing the paste, and the carbon fine particles gathered in the vicinity of both element electrodes. Then it was dried at 100 ° C for 10 minutes.

【0202】

to this Ink K; Water 70 wt.%, IPA (isopropanol) + ethylene glycol + PVA (polyvinyl alcohol) 30 wt.% Was mixed with palladium monoethanolamine acetate (PAME) to a metal concentration of 1 wt.%. thing Is applied to the substrate by an inkjet device and fired at 300 ° C for 10 minutes. At this time, in the vicinity of the device electrode where the carbon fine particles are present, Pd is not oxidized due to the reducing property of carbon and remains as a metal. On the other hand, since carbon fine particles are not sufficiently present near the center of the element electrode, Pd is oxidized and PdO becomes the main component. The portion composed of PdO near the center has a higher resistance than the portion composed of the surrounding metal Pd, and becomes a composition latent image.

【0203】

This element was subjected to a forming treatment and an activation treatment in the same manner as in Example 8, and the vacuum apparatus was exhausted while being heated to obtain a high vacuum. When the electron emission characteristics of this device were measured, the variation of the emission current Ie for each element was 6%. As a result of morphological observation by SEM, the electron emitting part was formed in the center of the device electrode, and the meandering width was small.

【0204】

Example 14 An electron emitting element was produced in the same manner as in Example 13 except that a blue plate glass substrate was used as the substrate and platinum carbon fine particles were used instead of the carbon fine particles. The platinum carbon fine particles used were those obtained by adsorbing platinum chloride on carbon fine particles having an average particle size of 30 nm, drying the particles, and reducing the particles at 700 ° C. for 4 hours.

【0205】

Subsequently, in the same manner as in Example 13, droplets of ink K are applied and fired to form a conductive thin film having the same composition latent image as in the above-mentioned Example, and the forming treatment and the activation treatment are also performed in the same manner. I did.

【0206】

The characteristics of this device were that the emission current Ie had a variation width of 5%, and the SEM observation results were almost the same as in Example 13.

【0207】

Example 15 In this embodiment, a quartz substrate was used, and an Au element electrode was formed by a photolithography technique.

【0208】

As an ink for forming a conductive film Ink L; Nickel (II) acetate dissolved in water so that the metal concentration is 2 wt.% Ink M; Chromium (III) acetate dissolved in water so that the metal concentration is 2 wt.% It was used.

【0209】

Process-1 An element having a configuration as schematically shown in Fig. 6A.B was manufactured. Ink L forms dot 4-1 and ink M forms dot 4-2. The droplet ejection conditions were controlled so that the dot 4-1 had a metal Ni film thickness of 40 nm and the dot 4-2 had a Cr film thickness of 10 nm.

【0210】

Process-2 Ar98% -H₂ Heat treatment is performed at 400 ° C for 10 minutes in a 2% mixed gas stream, and each of the above dots is decomposed into a metal film. After this, the temperature is raised to 500 ° C., held for 1 hour, and then slowly cooled. This is to form an alloy of Ni and Cr at the intersection of the two dots.

【0211】

Process-3 In the same manner as in Example 8, forming treatment and activation treatment were performed, and the inside of the vacuum device was made into a high vacuum by exhausting while holding the vacuum device at 200 ° C.

【0212】

After that, as a result of measuring the electron emission characteristics in the same manner as in Example 8, the variation of the emission current Ie was 11%. When the observation was performed by SEM after the measurement was completed, it was observed that the electron emitting part was formed at the intersection of both dots and the meandering width was narrowed.

【0213】

This is because the alloy of Ni80% -Cr20% is a typical composition of nichrome alloy and has a resistivity about two orders of magnitude higher than that of Ni, Cr alone. It seems that the electron emitting part fits in this region because heat is generated. Further, the metal Cr has a bcc crystal structure and Ni has a fcc crystal structure, but since the alloy having the above composition has a structure close to Ni, the interface between the alloy region and the Cr region is mechanical. It seems to be vulnerable to. Therefore, when the electron emitting portion is formed by the forming treatment, the effect that this portion triggers the formation of the electron emitting portion may contribute.

【0214】

[Effect of the invention]

As described above, even when the conductive film of the electron emitting element is formed by using the inkjet device by the method of the present invention, the conductive film is formed so as to have a structural latent image or a composition latent image. When forming an electron emitting part in the forming step following this, the position can be controlled as needed, such as near the center of the element electrode gap or near one of the element electrodes, and the meandering width can be reduced. Can be done. As a result, the uniformity of the electron emission characteristics can be improved, and the size of the bright spot on the fluorescent film can be reduced even when the element electrode gap is wide, so that a high-definition image can be displayed. It is possible to produce a suitable image forming apparatus, and further, it is possible to manufacture an image forming apparatus having low brightness unevenness and high image quality.

【0215】

Further, by using the inkjet device, it is possible to realize a manufacturing method having a wider degree of freedom in selecting the material used for forming the conductive film than the conventional method using a latent image.

【0216】

For example, when an attempt is made to form a configuration similar to that of Example 1 by a patterning method that does not use inkjet, the thinner film is formed and patterned, and then the thinner film that has already formed a patterning mask for the thicker film It must be formed on top of the film, coated with an organometallic solution, fired, and patterned by lift-off. Since it is necessary to form a patterning mask on the thinner film, the thinner film formed first needs to have a certain degree of adhesion to the substrate. When the material of the conductive film is an oxide such as PdO as in Example 1, there is a certain degree of adhesion to the glass substrate, which is possible, and the metal Pd is used as the material. In some cases, it can be patterned in the state of PdO and finally reduced to metal Pd. However, when Pt is used as a conductive film, it is extremely difficult to oxidize Pt, and the above-mentioned method cannot be adopted. The inkjet method can be easily realized by using an appropriate organic compound of Pt.

【0217】

Further, in the case of the configuration as in Example 15, the alloying of the intersection can be performed at a relatively low temperature because both dots overlap in the state of the metal compound, and alloying occurs during thermal decomposition. It appears to be. When this is attempted by two times of film formation and patterning as described above, for example, a patterned NiO film is first formed, a Cr film is formed therein, NiO is reduced to Ni, and then the intersection is formed. Must be alloyed. In this case, since Ni and Cr overlap in a metallic state, they do not alloy unless the atoms are sufficiently diffused from each other. For this purpose, it is necessary to process at a high temperature for a long time, which is difficult considering the heat resistance of a glass substrate or the like.

【0218】

In consideration of such circumstances, it will be understood that the use of the inkjet method has an advantage in realizing the improvement of the forming process while freely selecting the material of the conductive film.

[Simple explanation of drawings]

[Figure 1]

It is a schematic diagram which shows the 1st example of the structure of the element to which this invention is applied.

[Figure 2]

It is a schematic diagram which shows the 2nd example of the structure of the element to which this invention is applied.

[Fig. 3]

It is a schematic diagram which shows the 3rd example of the structure of the element to which this invention is applied.

[Fig. 4]

It is a schematic diagram which shows the 4th example of the structure of the element to which this invention is applied.

[Fig. 5]

It is a schematic diagram which shows the 5th example of the structure of the element to which this invention is applied.

[Fig. 6]

It is a schematic diagram which shows the sixth example of the structure of the element to which this invention is applied.

[Fig. 7]

It is a figure for demonstrating the waveform of the pulse voltage used in the forming process of this invention.

[Fig. 8]

It is a schematic diagram which shows the structure of the apparatus which measures the electron emission characteristic of the electron emission element manufactured by the method of this invention.

[Fig. 9]

It is a figure for demonstrating the characteristic of the electron emitting element manufactured by the method of this invention.

[Fig. 10]

It is a schematic diagram which shows the 1st example of the structure of the electron source to which this invention is applied.

[Fig. 11]

It is a schematic diagram which shows the structure of the image forming apparatus using the electron source shown in FIG.

[Fig. 12]

A and B are schematic views showing the configuration of a fluorescent film used in an image forming apparatus.

[Fig. 13]

It is a schematic diagram which shows the structure of the vacuum apparatus used when creating the image forming apparatus by the method of this invention.

[Fig. 14]

It is a schematic diagram which shows the connection method of the power source at the time of performing the forming process with respect to the electron source shown in FIG.

[Fig. 15]

It is a block diagram which shows the structure of the apparatus for displaying the image by the NTSC signal by the image forming apparatus created by this invention.

[Fig. 16]

It is a schematic diagram which shows the 2nd example of the structure of the electron source to which this invention is applied.

[Fig. 17]

It is a schematic diagram which shows the structure of the image forming apparatus using the electron source shown in FIG.

[Fig. 18]

It is a schematic diagram which shows an example of the structure of the conventional electron emission element.

[Fig. 19]

It is a schematic diagram which shows another example of the structure of the conventional electron emission element.

[Fig. 20]

It is a schematic diagram which shows an example of the process of the method of forming an electron emitting element by the method of this invention.

[Fig. 21]

It is a schematic diagram which shows an example of the process of the method of forming an electron emitting element by the method of this invention.

[Fig. 22]

It is a schematic diagram which shows the structure of the head of a bubble jet.

[Explanation of symbols]

1: Substrate, 2,3: Element electrode, 4: Conductive film, 4-1,4-2,4-3: Dots constituting the conductive film 4, 5: Electron emitting part, 11: Vacuum container, 12 : Exhaust pump, 13: Power supply for applying element voltage Vf to electron emitting element, 14: Current meter for measuring element current If flowing through conductive film 4 between element electrodes 2 and 3, 15: Element An anode electrode for capturing the emission current Ie emitted from the electron emission section 5, 16: a high-voltage power source for applying a voltage to the anode electrode 15, 17: emission current Ie emitted from the electron emission section 5 of the element. Current meter for measurement, 21: board, 22: X direction wiring, 23: Y direction wiring, 24: electron emitting element, 25: connection, 31: rear plate, 32: support frame, 33: glass substrate, 34: Fluorescent film, 35: Metal back, 36: Face plate, 37: Enclosure, 41: Black conductive material, 42: Fluorescent body, 51: Image forming device, 52: Exhaust pipe, 53: Vacuum chamber, 54: Gate valve, 55: Exhaust device, 56: Pressure gauge, 57: Quadrupole mass analyzer, 58: Gas introduction line, 59: Introduction amount control means, 60: Introduction material source, 61: Common electrode, 62: Power supply, 63: Conductor for current measurement, 64: Octograph, 71: Image forming device, 72: Scan circuit, 73: Control circuit, 74: Shift register, 75: Line memory, 76: Synchronous signal separation circuit, 77: Modulation signal generator , Vx, Va: DC voltage source, 81: Electron emitting element, 82, Dx1 ~ Dx10: Common wiring, 83: Grid electrode, 84: Electron transmission hole, 85, Dxo1, Dxo2, ...., Dxom: Common wiring Outer container terminal, 86: Grid electrode Outer container terminal, 91: Inkjet head, 92: Heater, 93: Solution flow path, 94: Discharge port, 95: Solution supply tube, 96-1,96-2: Ink droplets , Hv: High pressure terminal.